当前位置：文档库 › Hybrid electric vehicles and their challenges_ A review

Hybrid electric vehicles and their challenges_ A review

Hybrid electric vehicles and their challenges:A review

M.A.Hannan a,n,F.A.Azidin a,b,A.Mohamed a

a Department of Electrical,Electronic and Systems Engineering,Universiti Kebangsaan Malaysia,43600Bangi,Selangor,Malaysia

b Universiti Teknikal Malaysia Melaka,Hang Tuah Jaya,76109,Durian Tunggal,Melaka,Malaysia

a r t i c l e i n f o

Article history:

Received23August2012

Accepted26August2013

Available online17September2013

Keywords:

Fuel cell

Battery

Super capacitors

Energy management system

Hybrid electric vehicle

a b s t r a c t

There are numbers of alternative energy resources being studied for hybrid vehicles as preparation to

replace the exhausted supply of petroleum worldwide.The use of fossil fuel in the vehicles is a rising

concern due to its harmful environmental effects.Among other sources battery,fuel cell(FC),super

capacitors(SC)and photovoltaic cell i.e.solar are studied for vehicle https://www.wendangku.net/doc/b715360861.html,binations of these

sources of renewable energies can be applied for hybrid electric vehicle(HEV)for next generation of

transportation.Various aspects and techniques of HEV from energy management system(EMS),power

conditioning and propulsion system are explored in this paper.Other related?elds of HEV such as DC

machine and vehicle system are also included.Various type models and algorithms derived from

simulation and experiment are explained in details.The performances of the various combination of HEV

system are summarized in the table along with relevant references.This paper provides comprehensive

survey of hybrid electric vehicle on their source combination,models,energy management system(EMS)

etc.developed by various researchers.From the rigorous review,it is observed that the existing

technologies more or less can capable to perform HEV well;however,the reliability and the intelligent

systems are still not up to the mark.Accordingly,this review have been lighted many factors,challenges

and problems sustainable next generation hybrid vehicle.

Contents

1.Introduction (136)

2.Hybrid vehicle energy states (137)

2.1.Hybrid electric vehicle energy sources (137)

2.1.1.Battery model (138)

2.1.2.Fuel cell(FC)model (138)

2.1.3.Solar cell energy model (139)

2.2.Hybrid vehicle energy storage (139)

2.2.1.Super capacitors(SC)model (139)

2.2.2.HEV advanced energy storage system (140)

https://www.wendangku.net/doc/b715360861.html,bination of energy source with auxiliary energy storage for HEVs (140)

2.3.Hybrid vehicle energy conversion devices (141)

2.3.1.Power converter (141)

2.3.2.Improved FC control system (141)

3.Hybrid vehicle dynamic model (141)

3.1.Dynamic modeling hybrid system (141)

3.2.Dual clutch transmission(DCT)in PHEV (142)

3.3.Improved power-train for HEV (142)

3.4.Dynamic modeling FC powered scooter (142)

4.Characteristic and types of hybrid vehicle (142)

4.1.Characterization of HEV (142)

4.2.Auto rickshaw (143)

Contents lists available at ScienceDirect

journal homepage:https://www.wendangku.net/doc/b715360861.html,/locate/rser

Renewable and Sustainable Energy Reviews

https://www.wendangku.net/doc/b715360861.html,/10.1016/j.rser.2013.08.097

n Corresponding authors.Tel.:t60389217014.

E-mail address:hannan@https://www.wendangku.net/doc/b715360861.html,m.my(M.A.Hannan).

Renewable and Sustainable Energy Reviews29(2014)135–150

4.3.Plug-in HEV (143)

4.4.REVS based HEV (144)

4.5.Adaptive Neuro Fuzzy Interferences System in unmanned electric aerial vehicle (144)

5.Control and component system of HEV (144)

5.1.Control system (144)

5.1.1.Energy management system for HEV (144)

5.1.2.Control strategy for vehicle applications (144)

5.1.3.Control system for multi-sources energy model (144)

5.2.Applied HEV component model in control system (145)

5.2.1.DC machine (145)

5.2.2.Vehicle system (145)

6.Current challenges and problems (145)

6.1.Energy storage (146)

6.2.Power or energy management system (147)

6.2.1.System stability (147)

6.2.2.Uninterruptible power availability (147)

6.2.3.Dynamic resource allocation (147)

6.2.4.Power quality (147)

6.3.System con?guration and drive train structure (147)

6.4.Power electronics (148)

6.5.Motor generation (148)

7.Conclusion (148)

References (148)

1.Introduction

An emphasis on green technology is greatly demanded of modern cities.The signi?cant growth of today's cities has led to an increased use of transportation,resulting in increased pollution and other serious environmental problems.Gases produced by vehicle should be controlled and proactive measures should be taken to minimize these emissions.The automotive industry has introduced hybrid cars,such as the Honda Insight and the Toyota Prius that minimize the use of combustion engines by integrating them with electric motors[1].Such technology has a positive effect on the environment by reducing gas emission.The greatest challenge in research activities today is developing near zero-emission powered vehicles.Electric vehicles powered by renew-able energies offer a possible solution because they only emit natural byproducts and not exhaust fumes,which improve the air quality in cities and,thus the health of their populations[2].

One potential renewable energy device to power vehicles is the FC.A FC is an electrochemical device that produces DC electrical energy through a chemical reaction[3].It consists of an anode,an anode catalyst layer,an electrolyte,a cathode and a cathode catalyst layer.Multiple FCs are arranged in series or parallel in a stack to produce the desired voltage and current[4].FCs can be used for transportation applications from scooters to tramways,for combined heat and power(CHP)systems and in portable power supplies.In fact,the applications of FCs start at the small scale requiring200W and can reach the level of small power plants requiring500kW[5–7].FC technology uses hydrogen as the main source of energy that produces the electricity needed to drive an electric vehicle.In comparison to an internal combustion engine (ICE)that emits gases such as NO x and CO2,FC emits water as byproduct[8,9].However,the downside to FCs is their slow dynamic properties,and therefore,they require auxiliary sources, such as batteries and SCs[10].Batteries,which have high power density but low energy density have problem in longer charging time which can take from1h to several hours for full charge.On the positive side,batteries supply voltage more consistently than FCs.Batteries that are typically used with FCs,which are lead–acid, Li-ion and Ni–MH batteries[11].In the energy management system for hybrid vehicles,batteries can be charged during regenerative braking and from the residual energy of FCs in low and no load power systems.In this case,batteries are implemented for energy storage and can supply energy continuously depending on the charge and discharge time cycle.Unfortunately,batteries have a limited life cycle that depends on the operating temperature (approximately201C)and on the depth of discharge and the number of discharge cycles.Typically,lead-acid batteries can sustain1000cycles while Li-ion batteries are limited to2000cycles [11].In addition,Li-ion and Ni–MH batteries have a higher energy density and are lighter compared with lead–acid batteries.How-ever,lead–acid batteries have an advantage over other batteries in their cost and fast response to current changes[12].SCs also have the potential for power enhancement in vehicle applications.

SCs are electrochemical capacitors that offer higher power density in comparison with other storage device.They contain an electrical double layer and a separator that separates and holds the electrical charges.The separated charges provide a small amount of potential energy,as low as2–3V[13].The double layer is made of a nano-porous material such as activated carbon that can improve storage density.The capacitance values of SCs can reach3000F.Super capacitors or ultra capacitors have a few advantages over batteries such as a longer lifecycle(500,000 cycles),a very high rate of charge/discharge and low internal resistance,which means minimum heat loss and good reversibility [14].Furthermore,SCs have an ef?ciency cycle of approximately 90%whereas the ef?ciency cycle of a battery is approximately80%. However,SCs are not a source of high energy density.The amount of energy stored per unit weight of SCs is between3and 5W h kgà1,whereas that of a Li-ion battery is approximately 130–140W h kgà1[15].Therefore,the combination of SCs with FCs,which have low power density but high energy density,is a practical alternative to improve the ef?ciency and performance of HEVs.In addition,SCs have a high charging rate,which allows regenerative braking to be used more ef?ciently.As SCs have the potential to function as an energy storage device in the future, many industries are interested in fabricating SCs with new technology and material design.The lab experiment shows that the energy density of SCs can be reach up to300–400W h kgà1, however,future lithium based batteries are projected to achieve densities around400–600W h kgà1[13].The Fig.1shows com-parison between various energy sources and storage in terms of power and energy density.

M.A.Hannan et al./Renewable and Sustainable Energy Reviews29(2014)135–150 136

Another important source of renewable energy for the future is solar cells,also known as photovoltaic (PVs).Solar cells are electronic devices that convert sunlight into electricity [16].The clear advantage of solar cells over conventional fuels is their ability to convert free solar energy from the sun into electricity without generating signi ?cant pollution that might impact the ecology of the planet [17].Solar cells fall into three main categories:single-crystal silicon,which have the highest ef ?ciency of approximately 25%,polycrystalline silicon with 20%ef ?ciency,and amorphous silicon with approximately 10%ef ?ciency [18].Single-crystal silicon is the most expensive to produce followed by polycrystal-line silicon and then amorphous silicon.New solar cell technolo-gies emerging in the market are thin-?lm cells,gallium –arsenide cells and tandem PV cells.These technologies hold the promise of improving the ef ?ciency and versatility of solar cells while keeping production costs low [18].

Hybridization in using renewable energy is necessary because no single source currently matches the capability of fossil fuels in terms of both energy and power density.Simulation and modeling of HEVs has been extensively reported in the literature.Garcia et al.[19]and Barret [20]have discussed a FC-battery integrated with two dc/dc converters for a tramway.The active control system,which was the novelty of this paper,enabled both the FC and the battery to be coupled in the case of acceleration and regenerative braking.Another research paper on heavy load vehicles analyzed FC hybrid locomotives,which provided a reduc-tion in capital cost [21].The combination of batteries and FCs for FC hybrid vehicles was studied by Burnett and Borle [22],who indicated that hybridization minimizes the vehicle weight and fuel necessary as compared with FCs alone.The structure of a hybrid system using a SC and a battery was studied by Camara et al.[23],who linked a SC,to a boost converter with simple parallel topology.The parallel-structured hybrid system yielded a reduc-tion in the weight of the vehicle and required less smoothing inductances of the SC current.The application of a SC in FC hybrid power sources was found to be signi ?cant as it can assist the FC during its time response to instantaneous power demands,fuel starvations and voltage drops through aging effects [24].The behavior of HEV systems and internal combustion vehicles under a reference driving cycle has also been studied by Mierlo et al.[25].An innovative simulation model of FCs,batteries,SCs,?ywheels and engine-generators was developed to describe their function-ality and characteristics in a vehicle system.The Vehicle Simula-tion Program (VSP)software,which is undergoing development,shows high simulation accuracy and allows the evaluation of electric vehicles with complex power management strategies or with a hybrid drive train.

A hybridization system using a battery and SC with a PEMFC power source was found to provide improvements in both energy and power density.This work was veri ?ed by Thounthong et al.

[26]using the following component parameters:PEMFC (500W,50A),SC (292F,30V)and battery (68AH,24V).These researchers proved that the SC manages to balance the energy demand during the load transition period,and this additional storage of energy enhances the quality and ef ?ciency of the power system distribu-tion.Other researchers are interested in the implementation of solar energy,which is usually combined with a battery.Countries including Australia organize the Darwin-Adelaide World Solar Challenge to provide a challenging platform for developers of solar vehicles to showcase their most recent advances [27].These solar car races serve as an impetus to researchers to develop high-ef ?ciency solar –electric power sources coupled to aerodynamic bodies that minimize mechanical and electrical losses during operation.The dif ?culty of using a solar-generated source is that it has non-linear I –V characteristics and,as a consequence,the maximum power delivery to the load needs to be controlled [28,29].This need for maximum power point tracking (MPPT)has encouraged the involvement of many researchers in this area.A new design for a boost converter to improve the ef ?ciency of MPPT has been studied by Khatib and Mohamed [30]and Subiyanto in [31].Further innovative research involving solar-assisted electric auto rickshaw three-wheelers has also been performed [32]using various hybrid drive trains of plug-in,solar,battery and conventional engines.Studies of renewable energy relating to power electronics [33]and controlling PV applications [34]have also been conducted.

One crucial component in developing a HEV is its EMS,whose main tasks are to maximize,control and utilize generated energy to ful ?ll the demanded loads.Thounthong et al.[26,35]have reported on the energy management and control system of FCs,solar cells and SCs.A study of series and parallel plug-in hybrid electric vehicles (PHEVs)with dual clutch transmission was performed by Song et al.[36]and Salisa et al.[37]performed modeling and simulation of an EMS for a PHEV.The vehicle performance was compared with a standard U.S.EPA (Environ-mental Protection agency)drive cycle for highway driving.Bedir and Alouani [38]studied a simple power control strategy for HEVs that controlled the electric motor to provide power in different test situations.The vehicle model was implemented in the ADVISOR vehicle simulator,and preliminary tests indicated a 50%improvement in gas mileage.A study of the EMS of a PEMFC and battery in unmanned aerial vehicle (UAV)electric propulsion was conducted by Karunarathne et al.[39].The EMS evaluates feed-back from the battery,load power and FC parameters and passes this information to the power management system to control the power electronic interface.A fuzzy-based control strategy for hybrid vehicles was developed by Bahar et al.[40]and the EMS for the virtual vehicle design and application was investigated by Ustun et al.[41].

2.Hybrid vehicle energy states

The three categories for state of energy for HEV implementa-tion are energy sources,energy storage and energy conversion device.In the next section,reviews on some of the latest and past technologies implemented are discussed in detail.

2.1.Hybrid electric vehicle energy sources

In following section,three types of renewable energy models applied for the EV are analyzed.They are battery,fuel cell and solar energy

model.

https://www.wendangku.net/doc/b715360861.html,parison between various energy states in terms of power and energy density.

M.A.Hannan et al./Renewable and Sustainable Energy Reviews 29(2014)135–150137

2.1.1.Battery model

Lead acid batteries have been used for over one hundred years in electric vehicles.In 1900,28%of the vehicles in the United States were powered by electricity [42].Batteries are more ef ?cient as they can store and deliver energy.Lead –acid batteries undergo a reversible chemical reaction that can be described as Pb tPbO 2t2H 2SO 422PbSO 4t2H 2O

e1T

The performance of the battery has a large in ?uence on the state of charge (SOC)of the battery,battery capacity,temperature and aging [43].A simple battery model consists of constant resistance in series with an ideal voltage source.This simple model does not take the internal resistance and the SOC of the battery into account.The simple model can be improved by replacing R b with a variable resistance as shown in Fig.2(a).The linear electrical model measures the linear component for self-discharge,R p ,and various overvoltage in terms of the network circuit n m (t ).Although this model has improved accuracy,it does not consider tempera-ture dependency.Another model developed by Salameh et al.[44]is shown in Fig.2(b).This mathematical model is simulated in the BASIC program;it accounts for voltage and current drops and differentiates between internal and overvoltage resistances for charging and discharging.A more realistic dynamic model has been approached by adding two more element blocks into the circuit as shown in Fig.2(c)[44].In this new dynamic battery model,the V oc relies on the actual discharge current I B ,the energy drawn from the battery E cd and the battery temperature T .

A model of Nickel –Cadmium batteries during discharge has been developed by Sperandio et al.[45]and Green [46].The Nickel –Cadmium battery supplier provided the discharge voltage curve with ?xed current at room temperature.From there,data points were extracted to create the voltage curve as a function of time.The Nickel –Cadmium model is derived from the Paatero [47]model,which de ?ned the open circuit voltage as V OC ?a tb ?DOD tec td ?DOD TT

e2T

where T is the battery temperature,DOD is depth of discharge (DOD ?1àSOC)and a ,b ,c and d are ?tted model parameters,refer [47].A polymer Li-ion battery is evolved from lithium-ion bat-teries,with the difference that the electrolyte is composed of a polymeric material instead of an organic solvent [48].These batteries are widely used in portable applications,such as cell phones,PDAs,digital cameras and laptop computers.The storage capacity of a polymer Li-ion battery is in the range of 150–190W h kg à1and the power density ranges from 300to 1500W kg à1,which is 3–4times higher than a lead-acid battery [49].A dynamic battery model that considers the non-linear open-circuit voltage,current,temperature,life-cycle and storage time-dependent capacity to transient response has been proposed by Min Chen and Rincon-Mora [50].All parameters in the proposed model are extracted through the test system model using a polymer-Li-ion type TCL PL 383562battery.A computer was used to assist the test system in implementing a constant current –constant voltage to charge the polymer Li-ion battery and another computer-controlled current was used to discharge the batteries.Zinc –Bromide batteries provide advanced energy storage for vehicular applications.This storage device has high power and energy density of approximately 80–90W h kg à1and 300–600W kg à1,respectively [51].In addition,the life cycle is two to three times higher compared with other conventional batteries [52].Unlike other batteries,its electrode is not involved in a chemical reaction during charging but acts as a medium for the plating of zinc metal.Then,during discharging,the zinc dissolves back into the electrolyte.The electrochemical reaction that takes place in the zinc –bromide battery is during charging and dischar-ging [51,52].

2.1.2.Fuel cell (FC)model

Fuel cell (FC)is built of anode,anode catalyst layer,electrolyte,cathode and cathode catalyst layer [3].They can be arranged in series or parallel.DC electrical energy is produced through chemical reaction between hydrogen,H,and oxygen,O,occurs at the anode and cathode as follows:Anode:H 2-2H tt2e à

e3T

Cathode:1

O 2t2H t-H 2O e4TTheoretically,a single cell can generate 1.23V temperature of 251C at 1atm pressure.

Many empirical models in generating the FC voltage can be obtained from the literature involving the Nernst equation [53,54].According to Uzunoglu and Alam [55],a single cell of a FC generating voltage derived by the Nernst equation is described as

E cell ?E 0tRT

2F ln P H 2?????????P O 2p P H 2O e5T

where E 0is the standard potential of the hydrogen/oxygen reac-tion,R is the universal gas constant,F is Faraday ′s constant,T is

absolute temperature and P H 2and P H 2O are the partial pressures of water and oxygen,respectively,at the cathode.The

output

Fig. 2.(a)Improved battery model.(b)Improved battery model by Salameh.(c)Dynamic battery model.

M.A.Hannan et al./Renewable and Sustainable Energy Reviews 29(2014)135–150

138

voltage is the sum of the Nernst voltage,E cell ,the activation overvoltage,V act due to the “double layer effect ”in the electrical domain and the ohmic overvoltage,V ohm due to membrane resistance as derived as follows [56]:V f c ?E cell tV act tV ohm

e6T

The FC output voltage contains an additional voltage drop,V con due to the reduction in concentration of oxygen/hydrogen in the FC,V con is expressed in [57].

V con ?àB ln 1àJ

J max

e7T

where B (V )is a parametric coef ?cient that rely on the cell and operation state,J is actual current density of the cell (A/cm 2)and J max rated as 500–1500mA/cm 3.The FC output voltage is summar-ized as

V f c ?E cell tV act tV ohm tV con

e8T

In a comprehensive dynamic model,PEMFC current/voltage model is developed in [58].Furthermore,an improved output stack voltage of the PEMFC de ?ned by Chiu et al.[59]refers in [60,61]is as follows

E ?N E 0tRT 2

F ln P H 2P O 2P std

1=2P H 2O 8><>:9>=>;àL 0B @1

A e9T

where N is the number of cells in the stack and L is that voltage

loss,which consists of activation losses,internal current losses,resistive losses and concentration losses.An empirical PEMFC is developed by Kim et al.[62]to ?t the experimental cell potential E against current density.An exponential term was further added to improve the structure of the residual model of the cell potential as in expressed [63]as E ?E 0àiR àb log ei Tàme

e10T

where m and n are constants.A parametric model predicting the performance of a Ballard Mark PEMFC was proposed by Amphlett et al.[64,65].The model of the V stack is formulated as V stack ?E cell tn act tn ohm

e11T

where n act is activation polarization and n ohm is ohmic polarization.

The FC system in vehicle application is normally connected to the power diode to avoid reverse current ?ow to the system in a regenerative situation.Then,the FC system is linked to the dc/dc converter,which maintains a constant load voltage.

2.1.

3.Solar cell energy model

Photovoltaic (PV)or well-known solar cells are semiconductor devices which convert sunray into electrical energy in form of current.These semiconductor devices have similar characteristics to electronics devices such as diodes and transistor [66].The equivalent circuit of solar cell can be matched as a current source in parallel with a diode.The I –V characteristic of solar cell is determined from the Shockley equation which the current source I ,can be formulated as [67]

I ?I L àI 0e qv =KT eTà1h i e12Twhere I L is light generate current,I o initial current,V is the voltage,

k is the Boltzman constant,q is the electron charge and T is the absolute temperature.

Temperature and irradiance are two factors that affect solar cell's capacity.Increasing temperature reduces voltage value of solar cell at about 2.3mV/1C [68],whereas temperature variation of the current has minimum effect and is negligible.Irradiance is de ?ned as sum of power from a radiant source falls per unit area.

It is directly proportional to the short circuit current of a solar cell [69].Therefore,higher radiance will increase the photon ?ux number and thus will generate proportionally higher current.

Solar car park is built to harvest solar energy during midday.Research study by Hannan et al.[70]shows that this system is suitable for light electric vehicle,LEV.For the solar harvesting study case done in Malaysia,below formula is applied:

E solar ?Z t 1

t 2

?0:08t t64:1dt e13T

where E solar is solar energy harvested in one day for 1m 2solar panel,t 1is the harvesting start time and t 2is the harvesting stop time.After 8h,solar energy collected is about 1000–2000W h.From this collected solar energy,ΔE solar ,and the vehicle traction force F te ,the distance that a speci ?c weight of vehicle could travel,D veh ,can be calculated as follows [70]:D veh ?

n ΔE solar

F te

e14T

where n is the electric vehicle ef ?ciency.From the above equation,statistics of distance and the vehicle load values can be presented in a graph as shown in Fig.3.From this graph,it can be seen clearly that only vehicles with weight of less than 300kg are suitable to use solar energy from the solar car park.2.2.Hybrid vehicle energy storage

Energy storage has two important functions –as supplemen-tary source of energy for HEV and as support during regenerative braking.In the following section,review papers on this subject are discussed.

2.2.1.Super capacitors (SC)model

Super capacitors are special capacitors that produce substantial amounts of energy at low voltage.They contain an electrical double layer and a separator that separates and holds the electrical charges.The amount of energy that is stored in a SC can be derived from the energy stored in a capacitor,which can be measured in Coulombs as follows [71].Q SC ?

A ε

V SC ;OC e15T

where V sc,oc is the open circuit voltage of the SC,A is the plate area,d is the distance between plates and εis the permittivity.The open circuit voltage of the SC can be expressed in terms of capacitance C sc and charge q sc as [72]V SC ;OC ?

q SC C SC

e16

Fig.3.Distance traveled against energy used for various vehicle loads.

M.A.Hannan et al./Renewable and Sustainable Energy Reviews 29(2014)135–150139

The capacitance C sc can be varied slightly depending on the internal temperature and current of the SC as described by Rotenberg et al.[73].The charge of the SC is de?ned as

dq SC

?ài SCe17Twhere i sc is the charging current?ow.Positive and negative currents correspond to discharge and charge of the SC,respec-tively.The amount of charge remaining in the SC is de?ned as SOC as follows.

SOC?

V SC;OCàV SC;min

V SC;max SC;min

e18T

where V sc,max and V sc,min are the maximum and minimum open-circuit voltages.The effective output voltage,V SC,out,from the SC is determined by[74]as

V SC;out?V SC;OCài SC R SCe19Twhere R sc is the line resistance and is assumed to be the same during charge and discharge.The motor-consumed power P sc and the current drawn from the SC are as follows.

i SC?

P SC

V SC;out

e20T

The SC energy storage system is designed to aid a battery or FC in the case of high power demand in a hybrid vehicle system. The mathematical modeling of a SC can be related to the basic discharging circuit of capacitor voltage in terms of a resistor and capacitor,RC circuit.The effective discharging voltage is depen-dent on the initial voltage of the capacitor and the time constant RC which can be described as[74]

V SC;outetT?V SC;i eàt=RC

eTe21Twhere V sc,i is the initial voltage of the SC.One unique feature of a SC is that its voltage is directly proportional to the SOC.The amount of energy delivered by the SC is directly proportional to the capacitance and voltage change throughout the discharge as in de?ned[55]

E?1

C SC V2

sc;i

àV2sc;f

e22T

where V sc,f is the?nal voltage of the SC and C SC is capacitor value of SC.

The simple equivalent circuit model of the SC[55]consists of a capacitance C and a series resistance during charging and dischar-ging,represented by ESR or R as shown in Fig.4(a).The parallel resistance,EPR,representing the self-discharging losses has an impact only during the long-term energy storage of a SC.

The equivalent circuit proposed by Zubieta and Bonert[75]has three RC branches as shown in Fig.4(b).These branches have distinct time constants identifying fast current control charges. The parameters are determined by charging the SC from zero to the rated voltage and then observing the terminal voltage during the internal charge distribution for30min.The proposed equiva-lent circuit is designed from repeated measurements using a precisely timed and controlled current source.A study to deter-mine the equivalent circuit equation of an aqueous electrolyte SC was conducted by Yang et al.[76].That model describes the dynamics of the characteristics of the SC during the process of charging and discharging.The circuit model proposed by Yang is shown in Fig.4(c)[76].In contrast to a battery,the aging process of SCs does not rely on the lifecycle stress.The life expectancy of SCs is mostly driven by temperature and cell voltage[77].A number of SCs can be arranged in series and parallel to form a SC module that is capable of providing a certain amount of energy during accel-eration and peak load demand.The SC units that are built in series determine the amount of terminal voltage and the SC units that are connected in parallel determine the value of capacitance. The proper system to combine the SC with the overall load is by implementing a dc/dc converter to raise the voltage to the required voltage load.

2.2.2.HEV advanced energy storage system

Dynamic control using a switch between the battery and SC has been proposed by Lee et al.[78].The task was to improve the cycle life and ef?ciency of the battery in the vehicle.The control algorithm conducts a switch control that relies on the status of the SOC in the battery and the SC.Therefore,the use of the SC is optimized and can improve the life cycle of the battery.The analysis results show that charging and discharging at high current can shorten the battery life[72].Consequently,the system manages to improve it during engine restart,where the SC supports the high current needed to start the engine and during the charge time,low current is allowed to charge the battery.The switch to charge the battery is turned off if the battery SOC reaches70%,and the SC will take over the vehicle power line.This feature is a novelty of this system but still needs to be improved, especially to determine the accuracy of the SOC in the battery and SC.

2.2.

https://www.wendangku.net/doc/b715360861.html,bination of energy source with auxiliary energy storage for HEVs

The combination of a battery and SC in a multi-power system showed a better regulation of the vehicle traction system

dc Fig.4.(a)SC equivalent circuit.(b)SC equivalent circuit proposed by Zubieta.

(c)SC equivalent circuit proposed by Yang.

M.A.Hannan et al./Renewable and Sustainable Energy Reviews29(2014)135–150 140

voltage compared with a battery as a single power source [79].The model consists of a ZEBRA battery as the energy dense source and a SC as the power dense source.In the EMS,the SC has two functions that enhance the power demand and extend the battery life by compensating for the high current of the load [71].The algorithm strategy of the power management system follows three principles:the SC develops the demand current at high accelera-tion,the battery provides current according to the recommended rate and the remaining current is supported by the SC.These vehicle models were simulated with standard urban driving cycles as well as out-of-city or motorways.The analysis results indicate that the control strategies reduce vehicle fuel consumption and the EMS has a strong value for practical application.2.3.Hybrid vehicle energy conversion devices

Energy conversion devices are required to supply uniform voltage to the load.Review literatures on the usage of such devices in HEV are described in detail in following section.

2.3.1.Power converter

A power converter levels the voltage of multi-power sources depending on the rated voltage of the DC machine.A dc/dc converter will work with any motor drive technique like inverters to control the power ?ow in and out depending on the power condition [80].Power converters that are widely used for HEVs are buck,boost and ?uk topologies as shown in Fig.5.

The buck converter used by Castaner and Silvestre [29]is applied to step down the voltage as shown in Fig.5(a).The input voltage,V i ,is controlled by a switch over a period of duty cycle,D C and the average output voltage,V 0can de ?ned as

V 0?

1T Z t on

V i et Tdt ?D C V i e23Twhere T is a constant period and t on is the length of the ON state of the switch.

The boost converter is used to step-up [81]the voltage as shown in Fig.5(b).The inductor,L stores energy from the input voltage when the diode is in reverse bias.Thus,the energy transferred from the input voltage source V i to the output voltage source V 0can be described as V i àV 0?L

di L dt

e24T

where i L is the inductor current.The input and output voltage as a function of the duty cycle,D C ,can be expressed as V 0i ?T of f ?

e25T

The duty cycle,D C ,is given as a fraction of the switching period when switch S 1is closed and switch S 2is open.Goekdere et al.[82]also presented a bi-directional ?uk converter shown in Fig.5(c).The corresponding model is as di L 1dt ?v i àe1àD Tv c

L 1e26Tdi L 2dt ?Dv c àv o

L 2

e27Tdv c dt ?e1àD Ti L 1àDi L 2

e28T

where all components are referred to Fig.5(c)which are L 1and L 2are inductors,C is capacitor,v o is output voltage,v i is input voltage,v c is capacitor voltage,iL 1is current through L 1and iL 2is current through L 2.

Shuai Lu et al.[83–84]introduced a multilevel converter with cascaded cells (MCCC)in large vehicle propulsion.The new multi-level converter was designed so that it can integrate SCs without a DC –DC converter.The proposed topology contained top and bottom diode-clamped inverters.The top inverter,called a bulk inverter,provided the main DC supply.The bottom inverter,known as the conditioning inverter,was linked to the SCs.The proposed topology managed to regulate the SC voltage thoroughly and a DC –DC converter was no longer necessary.

2.3.2.Improved FC control system

The output power controlling the fuel cell to drive an electric motor through a DC/DC converter was studied by Zenith and Skogestad [85]and Zenith et al.[86].That study presents a control system based on switching rules in order to control the output voltage of the converter.A common pulse-width modulation control signal is applied to the system although there are other options such as sliding-mode control.The trajectories of the system are presented in the V C –I L plane depending on external disturbances such as the working voltage,or the voltage obtained by a FC under a rapidly switching current,and the external load current.A proper model system is satis ?ed but an unsatisfactory computational ef ?ciency results from the constant time of evalua-tion and not during the switching algorithm.

3.Hybrid vehicle dynamic model

In this section,a detail review on dynamic model of HEV technology is discussed comprehensively.3.1.Dynamic modeling hybrid system

Dynamic modeling of a FC/SC hybrid system was performed by Uzunoglu and Alam [55]and Onar et al.[87],who found

excellent

Fig.5.(a)A PSPICE model of the dc/dc Buck converter.(b)A PSPICE model of the dc/dc Boost converter.(c)A PSPICE model of the dc/dc ?uk converter.

M.A.Hannan et al./Renewable and Sustainable Energy Reviews 29(2014)135–150141

characteristics of vehicular application during power demand, steady-state and load switching.The SC assisted the FC if the power sharing technique in the control system was optimized.The analysis models were referred to the pro?le data from the urban dynamometer driving schedule(UDDS)of the advanced vehicle simulator(ADVISOR)software.The power sharing system was designed to arrange the FC and SC in parallel.The sources were connected to the switch before loading,and the opening of the switches followed the control algorithm,which was dependent on the power demand and deceleration.A PI controller was embedded to the system to improve the power converter system. The dynamic modeling proposed by Onar et al.[87]used wind/FC/ SC as the hybrid power generation system.The wind turbine supplied the demand load and any excess of energy was feed to an electrolyzer.The function of an electrolyzer is to generate hydro-gen for immediate use by the FC system or for storage[55].The FC system ful?lled any additional load demand.If the FC and wind turbine reached maximum power,the SC was another option for support of any extensive power demand for short periods only. The dynamic simulation model consisted of a wind turbine,an asynchronous induction generator,power factor correction capa-citors,a thyristor-controlled double bridge recti?er,two IGBT inverters,an electrolyzer,a hydrogen storage tank,a dc/dc con-verter,super capacitors,a fuel cell and a two-winding coupling transformer.

3.2.Dual clutch transmission(DCT)in PHEV

A study of an EMS for a PHEV was performed by Song et al.[37]. Instead of using gear reduction for transmissions such as Salisa et al.[38],this PHEV is equipped with a Dual Clutch Transmission (DCT).The dynamic performance of the vehicle,such as its fuel consumption,was analyzed.The control strategies of this system are more complex as it is built-up with a serial/parallel(S/P)HEV and is based on a driving and braking management system[88]. The driving mode is determined through three parameters:the speed of vehicle,the SOC and the throttle.Parallel braking is applied to the braking system.Two driving cycles,NEDC and UDDS,were used for analyzing the simulation result.The S/P PHEV control system needs less fuel consumption compared with the control strategy developed by ADVISOR and PHEV.

3.3.Improved power-train for HEV

A combination of a FC–SC-battery in a new vehicle topology power-train was introduced by Bauman[89]and Bauman and Kazerani[90].This superior topology uses a high power dc/dc converter for a FC in parallel with a low power dc/dc converter connected to the battery followed by anti-parallel switch across the diode.Unlike other topologies that use a similar system but without the anti-parallel switch and other conventional systems with a battery with a bidirectional converter parallel to a dc/dc converter for the FC[91],this advanced topology has many advantages including reduction in cost and mass by using a low-power boost converter,a high-ef?ciency path during charging and discharging of the battery and a SC that provides the majority of the current of the transient power,which prolongs the battery lifetime and offers simple modi?cation to a PHEV.

3.4.Dynamic modeling FC powered scooter

Chao et al.[92]in Taiwan conducted a simulation study of a motor scooter powered by a fuel cell and tested the non-linearity form of the power signal in electronics and electrical machines. Factors such as conduction and switching losses and temperature stress on the semiconductors were simulated[93].The fuel cell scooter simulation included an analysis of the power systems of the scooter,i.e.the battery,electrical and electronic compo-nents,the inverter and the permanent magnet synchronous motor (PMSM)and?eld oriented control(FOC)model.A position encoder can be used to detect the rotor position and then switch the phases to measure the phase current for modeling FOC applications.A hardware test was performed to verify the simula-tion data.For example,mileage simulations predicted that a fully-fueled vehicle has a travel range of80km.In fact,a range of 100.8km was achieved in actual tests.The fuel consumption simulation predicted a rate of1.6g hydrogen/km against1.34g hydrogen/km achieved in actual trials.These studies provide useful information on the design of fuel cell scooters not just when they operate under idealized theoretical conditions but also under realistic test situations.A cost analysis provides further evidence in support of the development of a commercially viable FC scooter[92].As a result,future studies should consider the infrastructure of FC stations.

4.Characteristic and types of hybrid vehicle

The characteristics and classi?cation of a hybrid vehicle along-side with three examples is presented in this section.The three HEV examples are auto-rickshaw,plug-in HEV and REVS-based HEV.At the end of the chapter,the Adaptive Neuro-Fuzzy Inter-ference System will be described.

4.1.Characterization of HEV

A study of the characteristics of a HEV was performed by Lukic et al.[94,95].HEVs have been categorized by their mechanical connections in series,parallel or series/parallel.For a series HEV, the electric motor is responsible for the propulsion power.Mean-while,the engine is used to recharge the battery.For a parallel HEV,both the electric motor and engine support power to the drive train.In a series/parallel HEV,an additional planetary gear set is used.This mechanical device allows energy?ow to the drive train either in series or parallel.Lukic et al.[94]introduced the concept of a hybridization factor,HF,to level the hybridization of a HEV.The classi?cation of HEVs by HF is categorized between HF?0(ICE vehicle)and HF?1(electric vehicle)where HF is expressed as

HF?

P EM

EMtP ICE

e29T

where P EM is the peak power of the electric motor and P ICE is the peak power of the ICE.

In the automobile industry,the manufacturer produces differ-ent types of HEVs to improve vehicle fuel economy and ef?ciency. These types can be classi?ed as follows[94,95]:

Micro-HEV(HF o0.1):Micro-HEVs use limited power of the EM as a combination of starter and alternator to provide a fast start/stop operation and then allowed the ICE to propel the vehicle,which means that the ICE can be stopped when the vehicle is in a standstill condition.As a result,it saves the fuel consumption of the vehicle by approximately10%,especially when traveling in urban city areas.

Mild-HEV(HF o0.25):Mild-HEVs have additional functions that can use the EM to boost the ICE during acceleration and can perform regenerative braking as well.However,the electric machine is not capable of driving the vehicle alone[96].It can save approximately10–20%of fuel consumption.

Power-assisted HEV(0.25o HF o0.5):Power-assisted HEVs can provide substantial electric propulsion to support ICE.For short

M.A.Hannan et al./Renewable and Sustainable Energy Reviews29(2014)135–150 142

distances,the vehicle can be turned into a fully electric system or become a zero-emissions vehicle,ZEV.The propulsion of the vehicle can also be guaranteed by the ICE alone.Fuel economy may be improved up to50%.

Plug-In HEV(HF40.5):A PHEV uses a battery as the storage device.The battery is recharged from a residential power grid.

These types of vehicles are accommodated with an on-board generator and ICE[78].

Vehicle that does not implement ICE such as Hybrid fuel cell vehicle,HFCV or battery EV,BEV(HF?1):BEV or PHEV, are grouped in this category.HFCV is considered as an electric vehicle since FC is a green technology component.On board the vehicle,stored hydrogen can be extracted by a reformer.The electricity gained by the FC will drive the electrical machine and normally be assisted by a SC to improve its low power response.

FC development has been signi?cantly researched but the major obstacles for the commercialization are cost,hydrogen storage and refueling infrastructures.Because oil prices are still affordable,HFCV is not yet a favorable option.

4.2.Auto rickshaw

Three-wheel vehicles(Auto Rickshaws)are a very popular and inexpensive transportation option in many Asian countries. They are mostly used in cities for short-distance traveling,have a capacity of5–7kW and are powered by ICEs.Recently,as a result of green technology concerns,small HEVs have been introduced with a different power system concept where the ICE is integrated with a battery and solar cells.A correlative analysis study of a three-wheeled rickshaw with various drive trains of hybrid con-?gurations has been successfully completed by Mulhall et al.[97] and Mulhall and Emadi[98].Four types of drive trains were studied:(i)drive trains with direct drives,(ii)drive trains with one electric motor,(iii)drive trains in parallel hybrid con?gura-tion,and(iv)drive train–conventional rickshaw with a solar-assisted auxiliary unit.For the electric vehicles,type (i)outperformed type(ii)because it used a direct-drive propulsion system;however,it is expensive.Type(iii)combines a motor and engine and type(iv)is a conventional auto rickshaw[97]. The simulation results indicated that an all-electric rickshaw can achieve acceptable range with a single charge.In addition to the work on the vehicle model,the recharge infrastructure has also been considered[98].The goals of this study were to accomplish ef?cient and effective battery-swap services,maximized usage of renewable sources and the design of a no-grid-interaction infrastructure.

An analysis of the electric propulsion motor for an auto rickshaw was also conducted.Various sizes and speeds of the motor were simulated using the advanced vehicle simulator (ADVISOR)to evaluate vehicle ef?ciency,gradeability and accel-eration[99].A driving cycle test from a real auto rickshaw in India was gathered using GPS data and was implemented in the simulation.Motor power,torque and speed were scaled before simulation.The gear ratio(GR)is set according to the different motor speeds for high motor/controller ef?ciency.An increase in motor size resulted in a slight drop in the motor/controller and vehicle economy and an increase in the maximum acceleration[97]. When the motor speed increased,both the motor/controller ef?ciency and vehicle economy rapidly decreased.An analysis of the relationship between motor size,speed and gradeability revealed an inconsistent trend.When the motor size increased,the top speed showed a slight drop or increase for speci?c rpm motors,while the gradeability tended to increase.The acceleration time increased as the motor size decreased.4.3.Plug-in HEV

Salisa et al.[100]developed a simulation model of an EMS for a Plug-in Hybrid Electric Vehicle(PHEV).The vehicle control strategy components that were required an energy storage system, an electric motor,a power control unit and an ICE.The PHEV simulation models in MATLAB/SIMULINK allowed the analysis of the performance,emissions and fuel economy of the vehicle[37]. The analysis result was veri?ed with the software tool ADVISOR, developed by the U.S.Department of Energy(DOE)and the National Renewable Energy Laboratory(NREL).The PHEV vehicle model was parameterized for an average sedan car that consisted of an energy storage system(ESS),an electrical machine,a combustion engine and transmissions.The driver controller was an integral and derivative(PID)controller that maneuvered the vehicle to the desired vehicle speed[100].The ESS contained a battery P B and a super capacitors bank P SC.The total power of the ESS,P ESS was de?ned as

P ESSetT?P BetTtP SCetTe30TThe battery model designed by Salisa et al.[99]consists of four blocks,where the open voltage of the battery pack is V OCpack and the internal resistance of the battery pack is R pack.The voltage drop V out of the battery is calculated using Kirchoff's law as:

V out?V OCpackàR pack I oute31T

The summarized output battery current I out with relation to the power demand P D can be de?ned as

I out?

V OCpackà

?????????????????????????????????????

OCpack

à4R pack P D

2R pack

e32T

The calculation of the battery residual capacity de?ned in terms of the SOC can be calculated as

SOC?

MAX capacityàAH used

àá

MAX capacity

e33T

where MAX capacity is maximum battery capacity and AH used is amount discharged current from battery.

The calculation of the voltage and output current of the SC model is similar to the battery model.The difference is the value of the total internal resistance of the SC changes during charging and discharging of the SC[77].The fuel economy and emission (FE combined)of the University of Technology Sydney UTS-PHEV were analyzed not only in a drive cycle test,such as HWFET or UDDS and combinations of both drive cycles,but also in a partial charged test(FE PCT)and fully charged test(FE FCT).Weighing city usage at55%and highway usage at45%,the combined fuel economy can be de?ned as

FE combined?

0:55

city

0:45

highway

e34T

The FE PCT test measures the fuel economy and emission of the vehicle when the system is at a low threshold operating level while the FE FCT is performed for the full operating system with the SOC at100%[100].The fuel economy of the FE PCT is measured in terms of the volume of fuel in gallons,V fuel and the distance in miles,D.

FE PCT?

V f uel

e35TThe fuel economy of the FCT is con?gured by

FE FCT?

V f ueltch arg e

E gasoline

e36T

M.A.Hannan et al./Renewable and Sustainable Energy Reviews29(2014)135–150143

where E charge is the electrical recharge energy in kWh and E gasoline is a constant equal to33.44k W h galà1.

The EMS controls the distribution of the power system compo-nents such as mechanical braking,regenerative braking,motor only driving,battery recharging,engine and motor assist and engine only mode depending on the power demand in accelera-tion and deceleration and the SOC level[37].The analysis results indicate that the PHEV simulation meets the target drive cycle of the ADVISOR in terms of vehicle speed,force and output power. In fact,the PHEV simulation have shown better results in the SOC level as it has a better EMS and can capture more regenerative braking energy.

4.4.REVS based HEV

Renewable energy vehicle simulator(REVS)provides visual programming interface to con?gure HEV and PHEV model system and EMS strategy.The model system REVS consists of several components including an electric motor,an ICE,fuzzy control strategies and renewable energy sources that can be simulated in different drive con?gurations.The ICE is simulated by IDEAS.

A model of series and parallel HEVs in REVS has been designed by Ghorbani et al.[101]to analyze the EMS and dynamic response of the system.The vehicle characteristics are derived from the model Toyota Prius[96].The power split device in the ICE supply driving force to propel of the vehicle and a generator,which generates the electricity to charge the battery.A power controller coordinates the EMS strategy by implementing fuzzy logic to compute the power?ow based on the inputs of the accelerator pedal and SOC of the battery[101].For the vehicle to follow the desired velocity,a low pass?lter is implemented together with the fuzzy logic controller.The results of the study indicate that the system model managed to follow the EMS strategy.

4.5.Adaptive Neuro Fuzzy Interferences System in unmanned electric aerial vehicle

Power and energy management systems for a FC and battery driven system,as studied by Karunarathne et al.[39],are designed for electric propulsion systems replacing ICE.The system has three components:the EMS,the power management system(PMS)and the power electronic interface(PEI).The EMS uses strategies that optimize the energy usage whereas the PMS develop policies for the PEI to control the DC/DC converter.The decisions of the EMS are based on the feedback input of the battery SOC and the power load to optimize energy sharing of the sources[87].Command signals executed by the EMS are passed onto the PMS,where a switching plan policy is de?ned.Simultaneously,the EMS is responsible for the control of the FC system to prevent oxygen starvation[35].The PEI consists of a DC/DC converter for the FC and battery,receives signal input from the PMS and boosts up the demanded energy load.The novelty of the study is the introduc-tion of an intelligent power management(IPM)system.The task of the IPM is to decide the operating power of the FC based on a Fuzzy Logic Rule Base System.In the case of nonlinear power characteristics of the hybrid system,an Adaptive Neuro Fuzzy Interferences System(ANFIS)is applied.

5.Control and component system of HEV

The content of following sections will focus to discuss about applicable control system and energy management system for both HEV as well as multi-sources energy model.5.1.Control system

Control system serves to coordinate power?ow from source to load.An optimized control system will improve vehicle ef?ciency, stability and performance.Selected review papers on this subject will be discussed in the next section.

5.1.1.Energy management system for HEV

The objective of the control system in an EMS is to improve the ef?ciency of the vehicle system.Without ef?ciency in the control system,the performance of the hybrid system is at an unsatisfac-tory level because each power source has capacity limitations. Selecting which power source to use or when a combination is necessary requires an intelligent control system[102].A powerful control system is essential for a good energy management system. For example,in order to optimize the FC/SC system[55],a control algorithm was designed that relied on the power demand condi-tion and is summarized as follows[102,103]:

In a low power demand condition,the FC system will generate

power to the load and any excess power will recharge the SC. In a high power demand condition,both the FC and SC will

generate power.

The generating power of the FC must be greater than700W to

avoid FC activation losses.

The release energy from regenerative braking will charge

the SC.

The buck-boost dc/dc power converter is used to provide a

constant load bus voltage.

5.1.2.Control strategy for vehicle applications

Another study of control strategy was conducted by Garcia[19] and Miller et al.[21].They investigated the application of a FC-battery hybrid system for tramways,focusing on the con?guration of a FC-battery powered system for a tramway in Metro Centre in Seville,Spain.The research involved designing an EMS with?xed reference signals for the FC dc/dc boost converter,electrical motor drives and energy dissipation in the braking chopper.The tramway EMS optimized the generated energy system in response to demand.It also managed the operation of the braking chopper when regenerative braking occurred.The EMS was controlled based on three levels of SOC as high(60%–65%),medium (42%–60%)and low(o40%),respectively Fig.6.

5.1.3.Control system for multi-sources energy model

Study on control system for multi-sources energy HEV was conducted by Hannan et al.[103]on a vehicle model is powered by battery,FC and SC.The control algorithm was developed to ful?ll various driving conditions.The logic design for the control algo-rithm is shown in Table1.For validation purposes,simulation

High SOC

Moderate

SOC

Low

Power Demand of Vehicle

Fig.6.EMS′s operation chart on PHEV.

M.A.Hannan et al./Renewable and Sustainable Energy Reviews29(2014)135–150 144

model was tested against the ECE-47drive cycle.Results accumu-lated support the fact that multi-sources vehicle with smart control strategy could be one of the solution for ef ?cient and green vehicle technology for the near future.For reference,simulation results are presented in Figs.7and 8[70].5.2.Applied HEV component model in control system

5.2.1.DC machine

Yang et al.[104]introduced a novel EMS for an electric scooter with an electronic gearshift and regenerative braking.The test scooter was driven directly by a four-phase axial-?ux DC brushless wheel motor.The task was to convert electrical energy into

mechanical energy to drive the vehicle and that of the latter was to manage the multi-sources and restore energy during regenera-tive braking.Faiz and Moayed-Zadeh [105]proposed models for the non-linear behavior of SRMs including:the non-linearity of B/H characteristics in ferromagnetic materials;the ?ux-linkage reliability on rotor position and stator winding current;Electrical input system from one point.Their SRM graphical models are based on Finite Element Model (FEM)analysis that ensures the results and analysis derived from motor designed.MATLAB SIMU-LINK offers a separately excited DC machine block for simulation in the EV system.The mathematical formula for an excited DC machine is described in [105]and depicted in Table 2.

5.2.2.Vehicle system

The physical model of the vehicle system is developed based on applied load during motion.Vehicle dynamic models have been explained in many literature reviews as in [41,42].The character-istics of the vehicle and the parameter coef ?cients that concern the vehicle are changed,depending on the vehicle design and the movement situation.Forces that occur during the movement of the vehicle,including the motor torque and speed,are evaluated.In some vehicle systems,the motor speed and torque are not directly linked to the linear movement of the vehicle but instead through the gear ratio and the radius of the vehicle drive wheel.The simulations model of the vehicle system developed by Williamson et al.[107,108]is tested under the Federal Urban Driving Schedule (FUDS)and High Way Fuel Economy Test (HWFET)drive cycle and their empirical model expresses instan-taneous power generation.An example model of vehicle system that is based on the MATLAB/SIMULINK is presented in the Table 3[106].

Important criteria such as technology,renewable energy source and electrical characteristic from all research studies found in chapter 1–5are summarized and compiled in Table 4.Table 5on the other hand makes comparison of the research methodology including the advantages and disadvantages of each approach.

6.Current challenges and problems

Hybrid electric vehicles are the promising future transport option for the next generation.As the price of crude oil has increased substantially over the past decades,consumers have been forced to seek alternatives energy sources for transportation [108].In contrast to hybrid vehicle with ICE,a BEV and PHEV are more energy ef ?cient and emit near to zero hazardous https://www.wendangku.net/doc/b715360861.html,rge group of researchers have contributed to improve ef ?ciency and performance of PHEV [109].From existing research,these technologies capable to perform HEV well,however,the reliability and the intelligent systems are still not up to the mark.Thus,there are many factors still need to be considered before HEV opened

Table 1

Logic control algorithm for various driving conditions.State Super-capacitor Fuel cell Battery Condition

1000Off operation/regenerative braking 2001BC is high;PD is Low and PO is low 3010BC is low;PD is low and PO is low 4011BC is high;PD is high and PO is low –100–(Not possible)

5101BC is High;PD is Low and PO is High 6110BC is low;PD is low and PO is high 7

11BC is high;PD is high and PO is high

BC ?battery SOC;PD ?power demand;PO ?pedal offset.

020406080100120

-10

Time/s

V e l o c i t y / k m /h

ECE-47

Vehicle speed

Fig.7.Simulation result of vehicle speed against the ECE-47drive cycle.

-10

010

2030

4050Time/s

V e l o c i t y / k m /h

Fig.8.Simulation result of single and multi-sources energy against the ECE-47drive cycle.

Table 2

DC machine/motor parameter.DC machine parameter

Values

Rated voltage,v (?eld and armature)

120V

Armature resistance,R a and inductance,L a 0.4382Ω,0.006763H Field resistance,R f and inductance,L f 84.91Ω,13.39H Field armature mutual inductance,L af 0.7096H

Total inertia,J

0.2053kg m 2Viscous friction coef ?cient,B m 0.007032N m s Coulomb friction torque,T f

5.282N m

M.A.Hannan et al./Renewable and Sustainable Energy Reviews 29(2014)135–150145

full swing in the market as well as number of current challenges are as follows [110]:

Renewable energy sources for vehicle applications have draw-backs in energy and power density.

The cost of these vehicles is still high.

The infrastructure of refueling stations needs to be measured.For a light vehicle,a small storage tank is required.As alter-native,exchange storage tank can be introduced.

A detailed study of hydrogen production for FCs,including delivery and storage tank systems,needs to be conducted.According to the Bossel (2004)[111],study of these works including refueling infrastructure has already done.That will cost trillions of dollars to become reality.

For plug-in BEVs,recharging is time-consuming and,thus,a study of rapid recharging systems is necessary.The development of lithium-ion batteries which have less weight and short recharge time has give positive impact for cars manufacturer in producing BEV and hybrid vehicles.Cars like Chevy Volt,Tesla S and Nissan leaf is the example comes from the new battery technology.

All these issues need to be addressed properly before BEVs and HEVs are ready for the public market.6.1.Energy storage

The main function of the energy storage in EV is to store electric energy during rechargeable and regenerative braking.The most common energy storage devices in EV are battery and SCs [1,2].Batteries typically consist of one third or more vehicle weight and size.They also have low life-cycle that required maintenance in 1–2years.These devices can provide readily electric power/energy in limited capability and then they needed to be recharged again.The United States of Advanced Battery Consortium plays a major role in developing and commercializing

Table 3

Characteristics of the vehicle's dynamic model parameters.

Vehicle model parameter Values Tire radius,r 0.26m Gear ratio,G

Vehicle mass tpassengers 240kg Frontal area,A

1.2m 2Drag coef ?cient,cd 0.75Rolling coef ?cient,u r 0.009

Air-density,d

1.25kg m à3Gravity acceleration,g

9.81m s à2

Table 4

Summaries of the hybrid vehicles parameters and technologies.No.Vehicle

description Research technology

Renewable energy

Operating voltage (V)

Power load

Ef ?ciency (%)

Ref.

1HEV-auto richshaw Proposed four drive train such as direct drive,one electric motor,parallel hybrid con ?guration,and conventional with solar assist.

Solar,battery 485–7kW 77–E 73–M [29,30]2Vehicular application Power sharing FC and SC with control algorithm.PI controller to improve power converter system

FC/SC 18858kW Better ES [44]3PHEV

EMS distribute power system and PID controller for propulsion

Plug-in $30043kW ICE 75kW EM UTS PHEV 4PHEV –FE [36,37]4Hybrid power generation Simulation power generation with electrolyze and hydrogen storage tank.Wind/FC/SC 400110k W Better ES 455PHEV-ICE Vehicle equipped by DCT and control strategies with serial/parallel/(S/P)HEV

Battery 30529kW-EM155kW-EM2 4.98–FE 356FCV

Simulate FC scooter with application of FOC control system.

FC,Battery o 48 3.6kW 43–CS 46

Automotive application Proposed HEV classi ?cation,review energy sources and EV topology connection

FC,SC,battery,?ywheel –

–

[42,43]

8HEV

Battery and SC in multi-power sources

Battery,SC $30032kW Improved ES [54]9HEV,PHEV –ICE Study Renewable Energy Vehicle Simulator (REVS)for HEV and PHEV Battery 40057kW ICE 50kW EM Better –FE [49]10HEV New vehicle topology power train with high power dc/dc converter FC and low dc/dc converter battery

Battery,FC,SC

42540kW 11.14–CS [51,52]11UAV

Design EMS,PMS and PEI with IPM system including Fuzzy logic and ANFIS Battery,FC 242kW Improved ES [39]12Automotive application Output power controlling for electric motor

FC 200410kW 420FC [55,56]13HEV

Dynamic controlled energy storage

Battery,SC 12/42o 6.5kW Better ES [57]14Transport application EMS for hybrid tramway in power distribution and braking operation Battery,FC 6254?120kW Better ES [17]15HEV Multilevel converter integrating SC for vehicle propulsion

Battery,SC 4204250kW Improved ES [92–93]16HEV Solar/hydrogen hybrid power system combining battery/FC for HEV Battery,SC,FC,solar 4215kW Better ES [20]17HEV Investigating FC and SC based on electric bicycle FC,SC

36300W 45FC [87]18HEV EMS in solar car race

Solar,battery 300 3.5kW 91EM [41]19EV EMS in directly-drive vehicle

Battery,SC 48 1.85kW 70

[95]20HEV HEV in virtual test bed environment

Battery,FC,SC

4250450kW Improved ES [91]21HEV

Control strategy in power management with various converter topology Battery,SC $270216kW Better E,ES [21]22Automotive application Study on hybridization of battery/FC/SC Battery,FC,SC

4210kW High ES [6,23,33]23HEV-ICE Control strategy based on Fuzzy logic control Battery 425030kW EM Better ES [40]24

HEV-ICE

Analysis of drive train ef ?ciency

Battery

$300

41kW ICE 75kW EM

Better M,ES

[98,99]

E –electrical,M –mechanical,FE –fuel economy,CS –cost saving,ES –energy saving.

M.A.Hannan et al./Renewable and Sustainable Energy Reviews 29(2014)135–150

146

advanced battery[112].The research seeks to increase the energy and power capability,extend life time,size,weight and cost of the batteries.SCs provide one tenth of electric energy consumed by battery and normally designed for secondary storage or power assistance.The increasing of SCs storage capacity certainly short-ens the recharging time of HEV.Since the voltage of SCs is directly proportional to SOC,an electronic controller is required to com-pensate the wide range of discharge voltage.New technology is required to solve the drawback of both storage devices[35,36].The proper control of the energy storage can be seen for both storage devices as a challenge and opportunity to discover in the power and energy management system.

6.2.Power or energy management system

An optimized integrated system of power and energy manage-ment system is another approach for EV application.The system aims to optimize the performance of the overall vehicle system through coordinate multi-power sources.These are the critical parameters to ensure a high achievement of the power or energy management system[70].

6.2.1.System stability

Automations power system in HEV employs power switching unit,converters which are susceptible to parameters such as temperature,switching-off power electronics and load variation [34].This disturbance from a change power demand,loss of power sources,short circuit and open circuit caused instability of the dynamic power system as all power devices and sources are interconnected[74].In order to maintain system stability,the EMS must be well-designed properly according standard operation of power and distribution system to ensure the system operates at its nominal power.

6.2.2.Uninterruptible power availability

On-board electronics devices of HEV must be consistently supply during operation.For a safety restraint,a backup power source is required in case of a short time primary power source interruption[112].In addition,this backup power source can support power demand during critical power load requirement.6.2.3.Dynamic resource allocation

The peak and power demand load differs depend on situation and condition of the vehicle.PMS and EMS should be able to optimize the available sources on-board and consequently manage them properly to meet requirement load.The task will be more complex when two or more power sources are available on-board. This management system must be followed by intelligent control algorithms that rely on priorities and schedules[112].

6.2.4.Power quality

The power quality in automotive power system guarantees the safety,stability and proper operation of power devices unit and electric loads[74].A high power quality manages to reduce noise and various transient during large current switching.Moreover, inadvertently disconnect from the large load may lead of voltage spike.

Thus,it is important to study these issues in designing power or energy management system to pursue maximum energy ef?ciency,achieve high vehicle performance and maintain low emission level[113].

6.3.System con?guration and drive train structure

Hybrid vehicles have two or more sources of energy in the vehicle.One is the main power source and the other is assist power source.The vehicle propulsion systems in HEV normally designed in series,parallel and series-parallel[106].A series hybrid drive train is not so complex and cheaper compare to the parallel and series-parallel con?guration.However if ICE is used,a series hybrid may suffer some disadvantages such as additional generator,maximum size of traction motor and less ef?cient after twice energy converting.This research study is important for selection in sizing of the HEV depend on cost,power and applica-tion[107].The DC dual-voltage system is the some of the interesting undergoing research develop by the automotive com-panies especially for HEV.This dual-voltage architecture manages to achieve a practical,dependable,low-cost and ef?cient in power distribution.Today,it becomes important challenge for automotive industries.

Table5

Outline methodology and advantages/disadvantages from selected review paper.

Title Methodology Advantages/disadvantages

Solar-assisted electric auto rickshaw three-wheeler New rickshaw design is simulated by using ADVISOR and is linked to

MATLAB/SIMULINK to analyze performance,economy and emission rate.

Adv:zero emissions.Good vehicle ef?ciency and performance

for small size motor.Disadv:a complex drive train design and

high cost of controller.

An EMS for a directly-driven electric scooter Experiment setup with six components including a core FPGA controller.

The NI Labview system record real-time measurement.

Adv:regenerative braking is20%higher and prolonged battery

lifecycle.Disadv:vehicle complexity.

Modeling of a Taiwan FC powered scooter FOC is applied to control power electronics to drive permanent magnet

synchronous motor.Drive control and vehicle characteristics embedded

C-code for DSP is simulated.

Adv:low cost and deliver better performance for vehicle.

Disadv:no regenerative braking system.

Electrical characteristic study of a Hybrid PEMFC and SC Small size PEMFC combined with SC for bicycle is set up.PIC controller is

developed for control system to regulate DC bus voltage and the load.

Adv:SC manages to protect FC during sudden load changing and

this prolong FC lifetime.Disadv:no regenerative braking system.

Modeling and Simulation of an EMS for PHEVs Analyze of power?ow and vehicle size are simulated in MATLAB/

SIMULINK.Results are compared with ADVISOR PHEV.

Adv:EMS mode is effective and show positive fuel ef?ciency.

Modeling and Simulation of a Series Parallel HEV Using REVS All vehicle components are integrated in a model and perform graphical

simulation in MATLAB/SIMULINK.Support by Fuzzy controllers for data

analysis.A complete system is called REVS.

Adv:offers data analysis from new designed HEV or PHEV.

SCs for power assis-tance in Hybrid Power Source with FC Several energy mode operations are introduced.Control management

strategy consists of inner loop controlling structure before being linked to

DC converter

Adv:FC performance improves and SC reduces fuel

consumption.

Modeling and control FC –battery hybrid system EMS controls all electrical components including motor controller.

Adaptive control based on states is designed and the system is simulated in

MATLAB/SIMULINK

Adv:zero emissions.Good vehicle ef?ciency and performance

for small size motor.

M.A.Hannan et al./Renewable and Sustainable Energy Reviews29(2014)135–150147

6.4.Power electronics

Power electronics is the power switching devices which asso-ciated with control system to drive electric motors[31].The requirements of these devices play a major role in HEV to improve drive system ef?ciency in vehicle driving range and fuel economy. In addition,the reliability and affordability of these systems may lead HEV to the market.The task of the system includes con-verters/inverters,control,power switching and integrated to any electronics devices[34].The issues such as switching loses during turn-on and turn-off,switching frequency of PWM operating mode,noise and EMI consideration,durability of the switching devices etc are the technical challenges of power devices.

6.5.Motor generation

Main component of an electric vehicle(EV)is the electric motor itself.The commonly used series wound brushed DC motors,AC motors,brushless DC motors,and permanent magnet motors are not up to the mark due their higher torque,complex speed control mechanism,expensive controllers and narrow rpm band[113]. Thus,for the next generation motor,a high ef?ciency,less complex controller,broader rpm band,a compact and ruggedness of the motor is necessary.In-wheel motor where motor and wheel are together is another option to increase ef?ciency of EV and to reduce cost[114].In addition,the implement of in-wheel motor shows some advantages as mechanical part like vehicle transmis-sion,gear and axle can be neglected.The application of in-wheel motor has been seen in electric scooter and solar car design [41–43].

The world is still depending on the crude oil as energy source for transportation.Each year the demand of fossil fuel is never decline but increase linearly.As we know that crude oil is not last forever and will be shortage in coming years.The fact is the maximum oil production could be decreased within5–10years [1,2]if there is no other new area of crude oil is discovered.This can lead a huge margin between offer and demand that give a great impact in the oil prices.As a result,a renewable energy for vehicle is the alternative power generation near future.

7.Conclusion

Hybrid vehicle systems powered by renewable energies are very important research interest of the researchers.Currently,few projects in the world involved in developing in this technology. The purpose of this review paper is to explain detail about hybrid vehicle technologies and their short comes.At the same time, attract researchers involved in this?eld for?nding new solution. Some related studies that have been discussed are renewable energies technology,energy management system and other related topics.Various form of model and description glance the overall system of HEV rather than to speci?c technology.This will initiate for further advance of HEV technology and creativity. Theoretically,current literature reviews suggested that BEV and PHEV have high potential to be our next generation of transporta-tion.Research shows that EMS supports these hybrid vehicle power systems by managing current?ows and coordinating multi power sources ef?ciently.These improve the performance of hybrid vehicle and utilize conservation of energy.Other study in energy-saving scheme by hybrid vehicle is the used of regenera-tive braking energy by braking chopper and multi-level inverter. Besides of intelligent control system,power electronics converters and electric propulsion which has been explained are the critical components for hybrid vehicle.Finally,mathematical models of HEV that develop by researchers have been successful simulated,are the important tools in investigating of hybrid vehicle perfor-mance.The continuous developing of technology will certainly push HEV for the future transportation.The innovative scienti?c research in reducing the manufacturing cost and the overall system may helps in booming the HEV market.

References

[1]Jorgensen K.Technologies for electric,hybrid and hydrogen vehicles:

electricity from renewable energy sources in transport.Utilities Policy 2008;16:72–9.

[2]Mierlo JV,Maggeto G,Lataire P.Which energy source for road transport in

the future?A comparison of battery,hybrid and fuel cell vehicles Energy Conversion and Management2006;47(17):2748–60.

[3]Basu S.Recent trends in fuel cell science and technology.New Delhi:

Springer;2007.

[4]Erdinc O,Uzunoglu M.Recent trends in PEM fuel cell-powered hybrid

systems:investigation of application areas,design architectures and energy management approaches.Renewable and Sustainable Energy Reviews 2010;14(9):2874–84.

[5]Duerr M,Cruden A,Gair S,McDonald JR.Dynamic model of a lead acid

battery for use in a domestic fuel cell system.Journal of Power Sources 2006;161(2):1400–11.

[6]Brouwer J.On the role of fuel cells and hydrogen in a more sustainable and

renewable.Journal of Current Applied Physics2010;10(2):9–17.

[7]Wee JH.Applications of proton exchange membrane fuel cell systems.

Renewable and Sustainable Energy Reviews2007;11(8):1720–38.

[8]Wee JH.Contribution of fuel cell systems to CO2emission reduction in their

application?elds.Renewable and Sustainable Energy Reviews2010;14

(2):735–44.

[9]Garcia CA,Manzini F,Islas J.Air emissions scenarios from ethanol as a

gasoline oxygenate in Mexico City Metropolitan Area.Renewable and Sustainable Energy Reviews2010;14(9):3032–40.

[10]Rao Z,Wang S.A review of power battery thermal energy management.

Renewable and Sustainable Energy Reviews2011;15(9):4554–71.

[11]Thounthong P,Chunkag V,Sethakul P,Davat B,Hinaje https://www.wendangku.net/doc/b715360861.html,parative study

of fuel-cell vehicle hybridization with battery or supercapacitor storage device.IEEE Transactions on Vehicular Technology2009;58(8):3892–904. [12]Burke AF.Batteries and ultracapacitors for electric,hybrid and fuel cell

vehicles.Proceeding of IEEE2007;95(4):806–20.

[13]Wikipedia.Electric double-layer capacitor.From website:?http://en.wikipe

https://www.wendangku.net/doc/b715360861.html,/wiki/Electric_double-layer_capacitor?;2012.

[14]Burke A.Ultracapacitors:why,how,and where is the technology.Journal of

Power Sources2000;91:37–50.

[15]Farcas C,Petreus D,Ciocan I,Palaghita N.Modeling and simulation of

supercapacitors.Design and technology of electronics packages,(SIITME) Gyula,Hungary;2009.

[16]Markvart T.Solar electricity.West Sussex:John Wiley&Sons;2001.

[17]Barrie JWB,Mecrow C,Jack AG,Atkinson DJ,Freeman AJ.Drive topologies for

solar-powered aircraft.IEEE Transactions on Industrial Electronics2010;57

(1):457–64.

[18]Wikipedia.Silicon.Available from website:?https://www.wendangku.net/doc/b715360861.html,/wiki/

Polycrystalline_silicon_photovoltaics#Forms_of_silicon?;2012.

[19]Garcia P,Fernandez LM,Garcia CA,Jurado F.Energy management system of

fuel-cell-battery hybrid tramway.IEEE Transactions on Industrial Electronics 2010;57:4013–23.

[20]Barret S.Japanese fuel cell rail vehicle in running tests.Fuel Cell Bulletin

2006;12:2–3.

[21]Miller AR,Peters J,Smith BE,Velev OA.Analysis of fuel cell hybrid

locomotives.Journal of Power Sources2006;157:855–61.

[22]Burnett MB,Borle LJ.A power system combining batteries and super-

capacitors in a solar/hydrogen hybrid electric vehicle.In:proceedings of the IEEE vehicle power and propulsion conference;2005.p.709–16. [23]Camara MB,Gualous H,Gustin F,Berthon A,Bakyo B.DC/DC converter

design for supercapacitor and battery power management in hybrid vehicle applications-polynomial control strategy.IEEE Industrial Electronics Society 2010;57:587–97.

[24]Azib T,Bethoux O,Remy G,Marchand C,Berthelot E.An innovative control

strategy of a single converter for hybrid fuel cell/supercapacitor power source.IEEE Transactions on Industrial Electronics2010;57:4024–31. [25]Mierlo JV,P.Vd Bossche,Maggeto G.Models of energy sources for EV and

HEV:fuel cells,batteries,ultracapacitors,?ywheels and engine-generators.

Journal of Power Sources2004;128:76–89.

[26]Thounthong P,Rael S,Davat B.Control strategy of fuel cell/supercapacitors

hybrid power sources for electric vehicle.Journal of Power Sources2006;158

(1):806–14.

[27]Lovatt HC,Ramsden VS,Mecrow BC.Design of an in-wheel motor for a solar-

powered electric vehicle.IEEE Electronics Power Application1998;145

(5):402–8.

[28]Wikipedia.Solar Cell.Available from website:?https://www.wendangku.net/doc/b715360861.html,/wiki/

Solar_cell?;2012.

[29]Castaner L,Silvestre S.Modelling photovoltaic systems using PSpice.New

Jersey:John Wiley&Sons,INC.;2003.

M.A.Hannan et al./Renewable and Sustainable Energy Reviews29(2014)135–150 148

[30]Khatib T,Mohamed A.High ef?cient standalone photovoltaic power system.

Saarbruecken:Lambert Academic Publishing;2010.

[31]Subiyanto Mohamed A,Hannan MA.Photovoltaic maximum power point

tracking controller using a new high performance boost converter.Interna-tional Review of Electrical Engineering2010;5:2535–45.

[32]Mallouh MA,Denman B,Surgenorb B,Peppley BA.Study of fuel cell hybrid

auto rickshaws using realistic urban drive cycles.Jordan Journal of Mechan-ical and Industrial Engineering2010;4(1):225–9.

[33]Arai J,Iba K,Funabashi T,Nakanishi Y,Koyanagi K,Yokoyama R.Power

electronics and its application to renewable energy in Japan.IEEE Circuits and Systems Magazines2008;8(30):69–76.

[34]Hannan MA,Ghani ZA,Mohamed A.An enhanced inverter controller for PV

applications using dSPACE platform.International Journal of Photoenergy 2010;2010:1–10.

[35]Thounthong P,Davat B,Rael S.Drive friendly.IEEE Power and Energy

Magazine2008;6(1):69–76.

[36]Song Z,Guangqiang W,Songlin Z.Study on the energy management strategy

of DCT-based series-parallel PHEV.International conference on computing, control and industrial engineering2010(1):p.25–9.

[37]Salisa AR,Zhang N,Zhu J.Modeling and simulation of an energy manage-

ment system for plug-in hybrid electric vehicles.Power engineering con-ference,AUPEC;2008.p.1–6.

[38]Bedir A,Alouani ATA.Simple power based control strategy for hybrid electric

vehicles.Vehicle power and propulsion conference,VPPC;2009.p.803–07.

[39]Karunarathne L,Economou JT,Knowles K.Adaptive neuro fuzzy inference

system-based intelligent power management strategies for fuel cell/battery driven unmanned electric aerial vehicle.Journal of Aerospace Engineering 2009;224:77–88.

[40]Bahar DM,Cimen MA,Tuncay RN.Developement of control strategy based

on fuzzy logic control for a parallel hybrid vehicle.In:Proceedings of the IEEE electrical and electronics engineering conference;2010.p.342–46. [41]Ustun O,Yilmaz M,Gockce C,Karakaya U,Tuncay RN.Energy management

method for solar race car design and application.In:Proceedings of the IEEE international on electric machines and drives conference IEMDC;2009.

p.804–11.

[42]Wisniewski DT.Solar?air:An open-road challenge.IEEE Potentials;2010

January/February.p.6–9.

[43]Ibrahim H,Ilinca A,Perron J.Energy storage systems—characteristics and

comparisons.Renewable and Sustainable Energy Reviews2008;12(5):1221–50.

[44]Salameh ZM,Casacca MA,Lynch WAA.Mathematical model for lead–acid

batteries.Transactions on Energy Conversion1992;7:93–8.

[45]Sperandio GS,Junior CLN,Adabo GJ.Modeling and simulation of nickel–

cadmium batteries during discharge.Aerospace Conference;2011.p.1–9. [46]Green A.The characteristics of the nickel–cadmium battery for energy

storage.Journal of Power Engineering1999;13(3):117–21.

[47]Paatero J.A mathematical model for?ooded nickel cadmium battery.

Department of Physics,Helsinki University of Technology.1997.

[48]Lithium-ion polymer.Wikipedia.Website from:?https://www.wendangku.net/doc/b715360861.html,/

wiki/Lithium-ion_polymer_battery?;2011.

[49]Wehrey MC.Whats new with electric hybrid vehicle.IEEE Power and Energy

Magazine2004;2:34–9.

[50]Chen M,Rincon-Mora GA.Accurate electrical battery model capable of

predicting runtime and I–V performance.IEEE Transactions on Energy Conversion2006;21:504–11.

[51]Swan DH,Dickinson B,Arikara M,Tomazic GS.Demonstration of a zinc

bromine battery in an electric vehicle.IEEE Aerospace and Electronic Systems Magazine1994;9:20–3.

[52]Manla E,Nasiri A,Rentel CH,Hughes M.Modeling of zinc bromide energy

storage for vehicular applications.IEEE Transactions on Industrial Electronics 2010;57:624–32.

[53]Choe SY,Ahn JW,Lee JG,Baek SH.Dynamic simulator for a PEM fuel cell

system with a PWM DC/DC converter.IEEE Transactions on Energy Conver-sion2008;23:669–80.

[54]Ceraolo M,Miulli C,Pozio A.Modeling static and dynamic behavior of proton

exchange membrane fuel cell on the basis of electrochemical description.

Journal of Power Sources2003;113:131–44.

[55]Uzunoglu M,Alam MS.Dynamic modeling,design and simulation of a PEM

fuel cell/ultra-capacitor hybrid system for vehicular applications.Energy Conversion and Management2007;48(5):1544–53.

[56]Al-Baghdadi MAR.Modelling of proton exchange membrane fuel cell

performance based on semi-empirical equations.Journal of Renewable Energy2005;30:1587–99.

[57]Gao F,Blunier B,Simoes MG,Miraoui A.PEM fuel cell stack modeling for

real-time emulation in hardware-in-the-loop applications.IEEE Transactions on Energy Conversion2011;26:184–94.

[58]Correa JM,Farret FA,Canha LN,Simoes MG.An electrochemical-based fuel-

cell model suitable for electrical engineering automation approach.IEEE Transactions on Industrial Electronics2004;51:1103–12.

[59]Chiu LY,Diong B,Gemmen RS.An improved small-signal model of the

dynamic behavior of PEM fuel cells.IEEE Transactions on Industry Applica-tions2004;40:970–7.

[60]Pasricha S,Keppler M,Shaw SR,Nehrir https://www.wendangku.net/doc/b715360861.html,parison and identi?cation of

static electrical terminal fuel cell models.IEEE Transactions on Energy Conversion2007;22:746–55.

[61]Pasricha S,Shaw SR.A dynamic PEM fuel cell model.IEEE Transactions on

Energy Conversion2010;21:484–90.[62]Kim J,Lee SM,Srinivasan S.Modeling of proton exchange membrane fuel cell

performance with an empirical equation.Journal of Electrochemical Society 1995;142:2670–4.

[63]Sousa R,Gonzalez ER.Mathematical modelling of polymer electrolyte fuel

cell.Journal of Power Sources2005;147:32–45.

[64]Amphlett JC,Mann RF,Peppley BA,Roberge PR,Rodrigues A.A model

predicting trasient response of proton exchange membrane fuel cells.Journal of Power Sources1999;61:183–8.

[65]Amphlett JC,Baumert RM,Mann RF,Peppley BA,Roberge PR,Harris TJ.

Performance modeling of the Ballard Mark IV solid polymer electrolyte fuel cell.II:Empirical model development.Journal of Electrochemistry Society, 142;1–8.

[66]Ribeiro HA,Sommeling PM,Kroon JM,Mendes A,Costa CAV.Dye-sensitized

solar cells:novel concepts,materials,and state-of-the-art performances.

International Journal of Green Energy2009;6:245–56.

[67]Kaygusuz K.Environmental impacts of the solar energy systems.Energy

Source Part A2009;31:1376–86.

[68]Khatib T,Mohamed A,Sopian K,Mahmoud M.Modeling of daily solar energy

on a horizontal surface for?ve main sites in Malaysia.International Journal of Green Energy2011;8:795–819.

[69]Khatib T,Mohamed A,Sopian K,Mahmoud M.Estimating ambient tempera-

ture for Malaysia using generalized regression neural network.International Journal of Green Energy2012;9:195–201.

[70]Hannan MA,Azidin FA,Mohamed A.Multi-sources model and control

algorithm of an energy management system for light electric vehicles.

Energy Conversion and Management2012;53(1):123–30.

[71]Ortuzar M,Moreno J,Dixon J.Ultracapacitor-based auxiliary energy system

for an electric vehicle:implementation and evaluation.IEEE Transactions on Industrial Electronics2007;54(4):2147–55.

[72]Miller JR.Introduction to electrochemical capacitor technology.IEEE Elec-

trical Insulation Magazine2010;26:40–7.

[73]Rotenberg D,Vahidi A,Kolmanovsky I.Ultracapacitor assisted powertrains:

modeling,control,sizing,and the impact on fuel economy.IEEE Transactions on Control Systems Technology2011;19:576–89.

[74]Hannan MA,Mohamed A.PSCAD/EMTDC simulation of uni?ed series-shunt

compensator for power quality improvement.IEEE Transactions on Power Delivery2005;20(2):1650–6.

[75]Zubieta L,Bonert R.Characterization of double-layer capacitors for power

electronics applications.IEEE Transactions on Industrial Applications 2000;36:199–205.

[76]Yang Z,Jianan S,Yicheng Z,Haiquan L.A new equivalent circuit model of

hybrid supercapacitor with aqueous electrolyte,power and energy engineer-ing conference;2011.p.1–4.

[77]Linzen D,Buller S,Karden E,Doncker RW.Analysis and evaluation of

charge-balancing circuits on performance,reliability,and lifetime of super-capacitor systems.IEEE Transactions on Industry Application2005;41: 1135–45.

[78]Lee BH,Shin DH,Song HS,Heo H,Kim HJ.Development of an advanced

hybrid energy storage system for hybrid electric vehicles.Journal of Power Electronics2009;9(1):51–60.

[79]Jarushi A,Scho?eld N.Modelling and analysis of energy source combinations

for electric vehicles.World Electric Vehicle Journal2009;3:1–7.

[80]Kirubakaran A,Jain S,Nema RK.A review on fuel cell technologies and power

electronic interface.Renewable and Sustainable Energy Reviews2009;13

(9):2430–40.

[81]Chakraborty A.Advancements in power electronics and drives in interface

with growing renewable energy resources.Renewable and Sustainable Energy Reviews2011;15(4):1816–27.

[82]Goekdere LU,Benlyazid K,Dougal RA,Santi E,Brice CW.A virtual prototype

for a hybrid electric vehicle.Journal of Mechatronics2002;12:575–93. [83]Lu S,Corzine KA,Ferdowsi MA.Unique ultracapacitor direct integration

scheme in multilevel motor drives for large vehicle propulsion.IEEE Transactions on Vehicular Technology2007;56:1506–15.

[84]Lu S,Corzine KA,Ferdowsi M.A new battery/ultracapacitor energy storage

system design and its motor drive integration for hybrid electric vehicles.

IEEE Transactions on Vehicular Technology2007;56:1516–23.

[85]Zenith F,Skogestad S.Control of fuel cell power output.Journal of Process

Control2007;17(4):333–47.

[86]Zenith F,Seland F,Konstein OE,Borresen B,Tunold R,Skogestad S.Control-

oriented modelling and experimental study of the transient response of a high-temperature polymer fuel cell.Journal of Power Sources 2006;162:215–27.

[87]Onar OC,Uzunoglu M,Alam MS.Dynamic modeling,design and simulation

of a wind/fuel cell/ultra-capacitor-based hybrid power generation system.

Journal of Power Sources2006;161(1):707–22.

[88]Bradley TH,Frank AA.Design,demonstrations and sustainability impact

assessments for plug-in hybrid electric vehicles.Renewable and Sustainable Energy Reviews2009;13(1):115–28.

[89]Baumann J.An analytical optimization method for improved fuel cell-

battery-ultracapacitor powertrain.IEEE Transactions on Vehicular Technol-ogy2009;58(7):3186–97.

[90]Bauman J,Kazerani M.A comparative study of fuel cell-battery,fuel cell-

ultracapacitor,and fuel cell-battery-ultracapacitor vehicles.IEEE Transaction on Vehicular Technology2008;57:760–9.

[91]Mekhilef S,Saidur R,Safari https://www.wendangku.net/doc/b715360861.html,parative study of different fuel cell

technologies.Renewable and Sustainable Energy Reviews2012;16(1):981–9.

M.A.Hannan et al./Renewable and Sustainable Energy Reviews29(2014)135–150149

[92]Chao DC-H,Duijsen PJv,Hwang JJ,Liao C-H.Modelling of a Taiwan fuel cell

powered scooter.In:Proceedings of the international conference on power electronics and drive system;2009.p.913–19.

[93]Hwang JJ.Sustainable transport strategy for promoting zero-emission

electric scooters in Taiwan.Renewable and Sustainable Energy Reviews 2010;14(5):1390–9.

[94]Lukic SM,Cao J,Bansal RC,Rodriguez F,Emadi A.Energy storage systems for

automotive applications.IEEE Transactions on Industrial Electronics2008;55

(6):2258–67.

[95]Lukic SM,Mulhall P,Emadi A.Energy autonomous solar/battery auto

rickshaw.Journal of Asian Electric Vehicles2008;6(2):1135–43.

[96]Chan CC,Bouscayrol A,Chen K.Electric,hybrid,and fuel-cell vehicles:

architectures and modeling.IEEE Transactions on Vehicular Technology 2010;59:589–97.

[97]Mullhall P,Lukic SM,Wirasingha SG,Lee YJ,Emadi A.Solar-assisted electric

auto rickshaw three-wheeler.IEEE Transactions on Vehicular Technology 2010;59:2298–307.

[98]Mulhall P,Emadi https://www.wendangku.net/doc/b715360861.html,prehensive simulations and comparative analysis of

the electric propulsion motor for a solar/battery electric auto rickshaw three-wheeler.In:proceedings of the thirty-?fth annual conference of IEEE on industrial electronics;2009.p.3785–90.

[99]Mahlia TMI,Tohno S,Tezuka T.History and current status of the motor

vehicle energy labeling and its implementation possibilities in Malaysia.

Renewable and Sustainable Energy Reviews2012;16(4):1828–44.

[100]Salisa AR,Zhang N,Zhu https://www.wendangku.net/doc/b715360861.html,parative analysis of fuel economy and emissions between a conventional HEV and the UTS PHEV.IEEE Transactions on Vehicular Technology2011;60:44–54.

[101]Ghorbani R,Bibeau E,Zanetel P,Karlis A.Modelling and simulation of a series parallel hybrid electric vehicle using REVS.In:Proceedings of the IEEE vehicle power and propulsion conference;2008.p.1–6.

[102]Blackwelder MJ,Dougal RA.Power coordination in a fuel cell-battery hybrid power source using commercial power controller circuits.Journal of Power Sources2004;134:139–47.[103]Hannan MA,Azidin FA,Mohamed A.Light vehicle energy management system using multi-power sources.Przeglad Elektrotechiczny(Electrical Review)2012;3:197–204.

[104]Yang YP,Liu JJ,Hu TH.An energy management system for a directly electric scooter.Journal of Energy Conversion and Management2011;52:621–9. [105]Faiz J,Moayed-Zadeh K.Design of switched reluctance machine for starter/ generator of hybrid electric vehicle.Journal of Power System Research 2005;75:153–60.

[106]I.MathWorks.SimPowerSystems.MATLAB;2008.

[107]Williamson SS,Emadi A,Rajashekara https://www.wendangku.net/doc/b715360861.html,prehensive ef?ciency modeling of electric.Traction motor drives for hybrid electric.Vehicle propulsion applications.IEEE Transactions onVehicular Technology2007;56:1561–72. [108]Williamson SS,Lukic SM,Emadi https://www.wendangku.net/doc/b715360861.html,prehensive drive train ef?ciency analysis of hybrid electric and fuel cell vehicles based on motor-controller ef?ciency modeling.IEEE Transactions on Power Electronics2006;21: 730–40.

[109]Atabani AE,Badruddin IA,Mekhilef S,Silitonga AS.A review on global fuel economy standards,labels and technologies in the transportation sector.

Renewable and Sustainable Energy Reviews2011;15(9):4586–610.

[110]Ong HC,Mahlia TMI,Masjuki HH.A review on energy pattern and policy for transportation sector in Malaysia.Renewable and Sustainable Energy Reviews2012;16(1):532–42.

[111]Bossel U.The hydrogen‘illusion’why electrons are a better energy carrier.

Cogeneration and On-Site Power Production Magazine;March–April2004.

p.55–9.

[112]Emadi A,Lee YJ,Rajashekara K.Power electronics and motor drives in electric,hybrid electric,and plug-in hybrid electric vehicles.IEEE Transac-tions on Industrial Electronics2008;55:2237–45.

[113]Emadi A.Handbook of automotive power electronics and motor drives.

Florida:Taylor&Francis Group,CRC Press;2005.

[114]Wang X,Shang J,Luo Z,Tang L,Zhang X,Li J.Reviews of power systems and environmental energy conversion for unmanned underwater vehicles.

Renewable and Sustainable Energy Reviews2012;16(4):1958–70.

M.A.Hannan et al./Renewable and Sustainable Energy Reviews29(2014)135–150 150

Web性能测试方案

Web性能测试方案 1测试目的此处阐述本次性能测试的目的，包括必要性分析与扩展性描述。性能测试最主要的目的是检验当前系统所处的性能水平，验证其性能是否能满足未来应用的需求，并进一步找出系统设计上的瓶颈，以期改善系统性能，达到用户的要求。 2测试范围此处主要描述本次性能测试的技术及业务背景，以及性能测试的特点。编写此方案的目的是为云应用产品提供web性能测试的方法，因此方案内容主要包括测试环境、测试工具、测试策略、测试指标与测试执行等。 2.1测试背景以云采业务为例，要满足用户在互联网集中采购的要求，实际业务中通过云采平台询报价、下单的频率较高，因此云采平台的性能直接决定了业务处理的效率，并能够支撑业务并发的压力。例如：支撑100家企业用户的集中访问，以及业务处理要求。 2.2性能度量指标响应时间（TTLB）即“time to last byte”，指的是从客户端发起的一个请求开始，到客户端接收到从服务器端返回的响应结束，这个过程所耗费的时间，响应时间的单位一般为“秒”或者“毫秒”。响应时间＝网络响应时间+应用程序响应时间。响应时间标准：

事务能力TPS（transaction per second）服务器每秒处理的事务数；一个事务是指一个客户机向服务器发送请求然后服务器做出反应的过程。客户机在发送请求时开始计时，收到服务器响应后结束计时，一次来计算使用的时间和完成的事务个数。它是衡量系统处理能力的重要指标。并发用户数同一时刻与服务器进行交互的在线用户数量。吞吐率（Throughput）单位时间内网络上传输的数据量，也可指单位时间内处理的客户端请求数量，是衡量网络性能的重要指标。吞吐率=吞吐量/传输时间资源利用率这里主要指CPU利用率（CPU utilization），内存占用率。 3测试内容此处对性能测试整体计划进行描述，包括测试内容以及关注的性能指标。Web性能测试内容包含：压力测试、负载测试、前端连接测试。 3.1负载测试负载测试是为了测量Web系统在某一负载级别上的性能，以保证Web系统在需求范围内能正常工作。负载级别可以是某个时刻同时访问Web系统的用户数量，也可以是在线数据处理的数量。例如：Web应用系统能允许多少个用户同时在线？如果超过了这个数量，会出现什么现象？Web应用系统能否处理大

计算机原理试题与答案

全国2004年4月高等教育自学考试计算机原理试题课程代码：02384 第一部分选择题（共25分）一、单项选择题（本大题共25小题，每小题1分，共25分）在每小题列出的四个选项中只有一个选项是符合题目要求的，请将其代码填写在题后的括号内。错选、多选或未选均无分。 1．计算机中一次处理的最大二进制位数即为（） A．位B．字节 C．字长D．代码 2．下列算式中属于逻辑运算的是（） A．1+1=2 B．1-1=0 C．1+1=10 D．1+1=1 3．下图所示的门电路，它的逻辑表达式是（） A．F=CD AB B．F=ABCD C．F=AB+CD D．F=ABCD 4．八进制数中的1位对应于二进制数的（） A．2位B．3位 C．4位D．5位 5．下列叙述正确的是（） A．原码是表示无符号数的编码方法 B．对一个数据的原码的各位取反而且在末位再加1就可以得到这个数据的补码

C．定点数表示的是整数 D．二进制数据表示在计算机中容易实现 6．浮点数0.00100011B×2-1的规格化表示是（） A．0.1000110B×2-11B B．0.0100011B×2-10B C．0.0100011B×20B D．0.1000110B×21B 7．两个定点数作补码加法运算，对相加后最高位出现进位1的处理是（） A．判为溢出B．AC中不保留 C．寄存在AC中D．循环加到末位 8．运算器中通用寄存器的长度一般取（） A．8位B．16位 C．32位D．等于计算机字长 9．目前在大多数微型机上广泛使用宽度为32/64位的高速总线是（） A．ISA B．EISA C．PCI D．VESA 10．某计算机指令的操作码有8个二进位，这种计算机的指令系统中的指令条数至多为（）A．8 B．64 C．128 D．256 11．间接访内指令LDA @Ad的指令周期包含CPU周期至少有（） A．一个B．二个 C．三个D．四个 12．在程序中，可用转移指令实现跳过后续的3条指令继续执行。这种指令的寻址方式是（） A．变址寻址方式B．相对寻址方式

h3c端口镜像配置及实例

1 配置本地端口镜像 2 1.2.1 配置任务简介本地端口镜像的配置需要在同一台设备上进行。首先创建一个本地镜像组，然后为该镜像组配置源端口和目的端口。表1-1 本地端口镜像配置任务简介 ●一个端口只能加入到一个镜像组。 ●源端口不能再被用作本镜像组或其它镜像组的出端口或目的端口。 3 1.2.2 创建本地镜像组表1-2 创建本地镜像组配置源端口目的端口后，本地镜像组才能生效。 4 1.2.3 配置源端口可以在系统视图下为指定镜像组配置一个或多个源端口，也可以在端口视图下将当前端口配置为指定镜像组的源端口，二者的配置效果相同。 1. 在系统视图下配置源端口表1-3 在系统视图下配置源端口

2. 在端口视图下配置源端口表1-4 在端口视图下配置源端口一个镜像组内可以配置多个源端口。 5 1.2.4 配置源CPU 表1-5 配置源CPU 一个镜像组内可以配置多个源CPU。 6 1.2.5 配置目的端口可以在系统视图下为指定镜像组配置目的端口，也可以在端口视图下将当前端口配置为指定镜像组的目的端口，二者的配置效果相同。

1. 在系统视图下配置目的端口表1-6 在系统视图下配置目的端口 2. 在端口视图下配置目的端口表1-7 在端口视图下配置目的端口 ●一个镜像组内只能配置一个目的端口。 ●请不要在目的端口上使能STP、MSTP和RSTP，否则会影响镜像功能的正常使用。 ●目的端口收到的报文包括复制自源端口的报文和来自其它端口的正常转发报文。为了保证数据监测设备只对源端口的报文进行分析，请将目的端口只用于端口镜像，不作其它用途。 ●镜像组的目的端口不能配置为已经接入RRPP环的端口。 7 1.3 配置二层远程端口镜像 8 1.3.1 配置任务简介二层远程端口镜像的配置需要分别在源设备和目的设备上进行。 ●一个端口只能加入到一个镜像组。 ●源端口不能再被用作本镜像组或其它镜像组的出端口或目的端口。 ●如果用户在设备上启用了GVRP（GARP VLAN Registration Protocol，GARP VLAN注册协议）功能，GVRP可能将远程镜像VLAN注册到不希望的端口上，此时在目的端口就会收到很多不必要的报文。有关GVRP的详细介绍，请参见“配置指导/03-接入/GVRP配置”。

品质体系框架图.

品质体系框架图图中各缩写词含义如下： QC：Quality Control 品质控制 QA：Quality Assurance 品质保证 QE：Quality Engineering 品质工程 IQC：Incoming Quality Control 来料品质控制 LQC：Line Quality Control 生产线品质控制 IPQC：In Process Quality Control 制程品质控制 FQC：Final Quality Control 最终品质控制 SQA：Source (Supplier) Quality Assurance 供应商品质控制 DCC：Document Control Center 文控中心 PQA：Process Quality Assurance 制程品质保证 FQA：Final Quality Assurance 最终品质保证 DAS：Defects Analysis System 缺陷分析系统 FA：Failure Analysis 坏品分析 CPI：Continuous Process Improvement 连续工序改善 CS：Customer Service 客户服务 TRAINNING：培训一供应商品质保证（SQA） 1.SQA概念 SQA即供应商品质保证，识通过在供应商处设立专人进行抽样检验，并定期对供应商进行审核、评价而从最源头实施品质保证的一种方法。是以预防为主思想的体现。

2.SQA组织结构 3.主要职责 1）对从来料品质控制（IQC）/生产及其他渠道所获取的信息进行分析、综合，把结果反馈给供应商，并要求改善。 2）耕具派驻检验远提供的品质情报对供应商品质进行跟踪。 3）定期对供应商进行审核，及时发现品质隐患。 4）根据实际不定期给供应商导入先进的品质管理手法及检验手段，推动其品质保证能力的提升。 5）根据公司的生产反馈情况、派驻人员检验结果、对投宿反应速度及态度对供应商进行排序，为公司对供应商的取舍提供依据。 4.供应商品质管理的主要办法 1）派驻检验员把IQC移至供应商，使得及早发现问题，便于供应商及时返工，降低供应商的品质成本，便于本公司快速反应，对本公司的品质保证有利。同时可以根据本公司的实际使用情况及IQC的检验情况，专门严加检查问题项目，针对性强。 2）定期审核通过组织各方面的专家对供应商进行审核，有利于全面把握供应商的综合能力，及时发现薄弱环节并要求改善，从而从体系上保证供货品质定期排序，此结果亦为供应商进行排序提供依据。一般审核项目包含以下几个方面 A．品质。 B．生产支持。 C．技术能力及新产品导入。 D．一般事务. 具体内容请看“供应商调查确认表”. 3）定期排序排序的主要目的是评估供应商的品质及综合能力，以及为是否保留、更换供应商提供决策依据.排序主要依据以下几个方面的内容： A.SQA批通过率：一般要求不低于95%。 B.IQC批合格率：一般要求不低于95%。

天线分集技术的原理

天线分集技术的原理最初，许多设计者可能会担心区域规范的复杂性问题，因为在全世界范围内，不同区域规范也各异。然而，只要多加研究便能了解并符合不同区域的法规，因为在每一个地区，通常都会有一个政府单位负责颁布相关文件，以说明“符合特定目的的发射端相关的规则。无线电通信中更难于理解的部分在于无线电通信链路质量与多种外部因素相关，多种可变因素交织在一起产生了复杂的传输环境，而这种传输环境通常很难解释清楚。然而，掌握基本概念往往有助于理解多变的无线电通信链接品质，一旦理解了这些基本概念，其中许多问题可以通过一种低成本、易实现的被称作天线分集(antenna diversity)的技术来实现。环境因素的考虑影响无线电通信链路持续稳定的首要环境因素是被称为多径/衰落和天线极化/分集的现象。这些现象对于链路质量的影响要么是建设性的要么是破坏性的，这取决于不同的特定环境。可能发生的情况太多了，于是，当我们试着要了解特定的环境条件在某个时间点对无线电通信链接的作用，以及会造成何种链接质量时，这无疑是非常困难的。天线极化/分集这种被称为天线极化的现象是由给定天线的方向属性引起的，虽然有时候把天线极化解释为在某些无线电通信链路质量上的衰减，但是一些无线电通信设计者经常利用这一特性来调整天线，通过限制收发信号在限定的方向范围之内达其所需。这是可行的，因为天线在各个方向上的辐射不均衡，并且利用这一特性能够屏蔽其他（方向）来源的射频噪声。简单的说，天线分为全向和定向两种。全向天线收发信号时，在各个方向的强度相同，而定向天线的收发信号被限定在一个方向范围之内。若要打造高度稳固的链接，首先就要从了解此应用开始。例如：如果一个链路上的信号仅来自于特定的方向，那么选择定向天线获

性能测试流程规范

目录 1前言 (2) 1.1 文档目的 (2) 1.2 适用对象 (2) 2性能测试目的 (2) 3性能测试所处的位置及相关人员 (3) 3.1 性能测试所处的位置及其基本流程 (3) 3.2 性能测试工作内容 (4) 3.3 性能测试涉及的人员角色 (5) 4性能测试实施规范 (5) 4.1 确定性能测试需求 (5) 4.1.1 分析应用系统，剥离出需测试的性能点 (5) 4.1.2 分析需求点制定单元测试用例 (6) 4.1.3 性能测试需求评审 (6) 4.1.4 性能测试需求归档 (6) 4.2 性能测试具体实施规范 (6) 4.2.1 性能测试起始时间 (6) 4.2.2 制定和编写性能测试计划、方案以及测试用例 (7) 4.2.3 测试环境搭建 (7) 4.2.4 验证测试环境 (8) 4.2.5 编写测试用例脚本 (8) 4.2.6 调试测试用例脚本 (8) 4.2.7 预测试 (9) 4.2.8 正式测试 (9) 4.2.9 测试数据分析 (9) 4.2.10 调整系统环境和修改程序 (10) 4.2.11 回归测试 (10) 4.2.12 测试评估报告 (10) 4.2.13 测试分析报告 (10) 5测试脚本和测试用例管理 (11) 6性能测试归档管理 (11) 7性能测试工作总结 (11) 8附录：............................................................................................. 错误！未定义书签。

1前言 1.1 文档目的本文档的目的在于明确性能测试流程规范，以便于相关人员的使用，保证性能测试脚本的可用性和可维护性，提高测试工作的自动化程度，增加测试的可靠性、重用性和客观性。 1.2 适用对象本文档适用于部门内测试组成员、项目相关人员、QA及高级经理阅读。 2性能测试目的性能测试到底能做些什么，能解决哪些问题呢？系统开发人员，维护人员及测试人员在工作中都可能遇到如下的问题 1.硬件选型，我们的系统快上线了，我们应该购置什么样硬件配置的电脑作为服务器呢？ 2.我们的系统刚上线，正处在试运行阶段，用户要求提供符合当初提出性能要求的报告才能验收通过，我们该如何做？ 3.我们的系统已经运行了一段时间，为了保证系统在运行过程中一直能够提供给用户良好的体验（良好的性能），我们该怎么办？ 4.明年这个系统的用户数将会大幅度增加，到时我们的系统是否还能支持这么多的用户访问，是否通过调整软件可以实现，是增加硬件还是软件，哪种方式最有效？ 5.我们的系统存在问题，达不到预期的性能要求，这是什么原因引起的，我们应该进行怎样的调整？ 6.在测试或者系统试点试运行阶段我们的系统一直表现得很好，但产品正式上线后，在用户实际环境下，总是会出现这样那样莫名其妙的问题，例如系统运行一段时间后变慢，某些应用自动退出，出现应用挂死现象，导致用户对我们的产品不满意，这些问题是否能避免，提早发现？ 7.系统即将上线，应该如何部署效果会更好呢？并发性能测试的目的注要体现在三个方面：以真实的业务为依据，选择有代表性的、关键的业务操作设计测试案例，以评价系统的当前性能；当扩展应用程序的功能或者新的应用程序将要被部署时，负载测试会帮助确定系统是否还能够处理期望的用户负载，以预测系统的未来性能；通过模拟成百上千个用户，重复执行和运行测试，可以确认性能瓶颈并优化和调整应用，目的在于寻找到瓶颈问题。

计算机组成原理试题及答案

二、填空题 1 字符信息是符号数据，属于处理（非数值）领域的问题，国际上采用的字符系统是七单位的（ASCII）码。P23 2 按IEEE754标准，一个32位浮点数由符号位S（1位）、阶码E（8位）、尾数M（23位）三个域组成。其中阶码E的值等于指数的真值（e）加上一个固定的偏移值（127）。P17 3 双端口存储器和多模块交叉存储器属于并行存储器结构，其中前者采用（空间）并行技术，后者采用（时间）并行技术。P86 4 衡量总线性能的重要指标是（总线带宽），它定义为总线本身所能达到的最高传输速率，单位是（MB/s）。P185 5 在计算机术语中，将ALU控制器和（）存储器合在一起称为（）。 6 数的真值变成机器码可采用原码表示法，反码表示法，（补码）表示法，（移码）表示法。P19-P21 7 广泛使用的（SRAM）和（DRAM）都是半导体随机读写存储器。前者的速度比后者快，但集成度不如后者高。P67 8 反映主存速度指标的三个术语是存取时间、（存储周期）和（存储器带宽）。P67 9 形成指令地址的方法称为指令寻址，通常是（顺序）寻址，遇到转移指令时（跳跃）寻址。P112 10 CPU从（主存中）取出一条指令并执行这条指令的时间和称为（指令周期）。 11 定点32位字长的字，采用2的补码形式表示时，一个字所能表示

的整数范围是（-2的31次方到2的31次方减1 ）。P20 12 IEEE754标准规定的64位浮点数格式中，符号位为1位，阶码为11位，尾数为52位，则它能表示的最大规格化正数为（+［1+（1-2 ）］×2 ）。 13 浮点加、减法运算的步骤是（0操作处理）、（比较阶码大小并完成对阶）、（尾数进行加或减运算）、（结果规格化并进行舍入处理）、（溢出处理）。P54 14 某计算机字长32位，其存储容量为64MB，若按字编址，它的存储系统的地址线至少需要（14）条。64×1024KB=2048KB(寻址范32围)=2048×8(化为字的形式)=214 15一个组相联映射的Cache，有128块，每组4块，主存共有16384块，每块64个字，则主存地址共（20）位，其中主存字块标记应为（9）位，组地址应为（5）位，Cache地址共（13）位。 16 CPU存取出一条指令并执行该指令的时间叫（指令周期），它通常包含若干个（CPU周期），而后者又包含若干个（时钟周期）。P131 17 计算机系统的层次结构从下至上可分为五级，即微程序设计级（或逻辑电路级）、一般机器级、操作系统级、（汇编语言）级、（高级语言）级。P13 18十进制数在计算机内有两种表示形式：（字符串）形式和（压缩的十进制数串）形式。前者主要用在非数值计算的应用领域，后者用于直接完成十进制数的算术运算。P19 19一个定点数由符号位和数值域两部分组成。按小数点位置不同，

华为交换机端口镜像配置举例

华为交换机端口镜像配置举例配置实例文章出处：https://www.wendangku.net/doc/b715360861.html, 端口镜像是将指定端口的报文复制到镜像目的端口，镜像目的端口会接入数据监测设备，用户利用这些设备分析目的端口接收到的报文，进行网络监控和故障排除。本文介绍一个在华为交换机上通过配置端口镜像实现对数据监测的应用案例，详细的组网结构及配置步骤请查看以下内容。某公司内部通过交换机实现各部门之间的互连，网络环境描述如下： 1）研发部通过端口Ethernet 1/0/1接入Switch C；λ 2）市场部通过端口Ethernet 1/0/2接入Switch C；λ 3）数据监测设备连接在Switch C的Ethernet 1/0/3端口上。λ 网络管理员希望通过数据监测设备对研发部和市场部收发的报文进行监控。使用本地端口镜像功能实现该需求，在Switch C上进行如下配置： 1）端口Ethernet 1/0/1和Ethernet 1/0/2为镜像源端口；λ 2）连接数据监测设备的端口Ethernet 1/0/3为镜像目的端口。λ 配置步骤配置Switch C： # 创建本地镜像组。

system-view [SwitchC] mirroring-group 1 local # 为本地镜像组配置源端口和目的端口。 [SwitchC] mirroring-group 1 mirroring-port Ethernet 1/0/1 Ethernet 1/0/2 both [SwitchC] mirroring-group 1 monitor-port Ethernet 1/0/3 # 显示所有镜像组的配置信息。 [SwitchC] display mirroring-group all mirroring-group 1: type: local status: active mirroring port: Ethernet1/0/1 both Ethernet1/0/2 both monitor port: Ethernet1/0/3 配置完成后，用户就可以在Server上监控部门1和部门2收发的所有报文。相关文章：端口镜像技术简介远程端口镜像配置举例

计算机组成原理参考答案汇总

红色标记为找到了的参考答案，问答题比较全，绿色标记为个人做的，仅供参考！第一章计算机系统概述 1. 目前的计算机中，代码形式是______。 A．指令以二进制形式存放，数据以十进制形式存放 B．指令以十进制形式存放，数据以二进制形式存放 C．指令和数据都以二进制形式存放 D．指令和数据都以十进制形式存放 2. 完整的计算机系统应包括______。 A. 运算器、存储器、控制器 B. 外部设备和主机 C. 主机和实用程序 D. 配套的硬件设备和软件系统 3. 目前我们所说的个人台式商用机属于______。 A.巨型机 B.中型机 C.小型机 D.微型机 4. Intel80486是32位微处理器，Pentium是______位微处理器。Ａ．１６Ｂ．３２Ｃ．４８Ｄ．６４ 5. 下列______属于应用软件。 A. 操作系统 B. 编译系统 C. 连接程序 D.文本处理 6. 目前的计算机，从原理上讲______。 A.指令以二进制形式存放，数据以十进制形式存放 B.指令以十进制形式存放，数据以二进制形式存放 C.指令和数据都以二进制形式存放 D.指令和数据都以十进制形式存放 7. 计算机问世至今，新型机器不断推陈出新，不管怎样更新，依然保有“存储程序”的概念，最早提出这种概念的是______。 A.巴贝奇 B.冯. 诺依曼 C.帕斯卡 D.贝尔 8.通常划分计算机发展时代是以（）为标准 A.所用的电子器件 B.运算速度 C.计算机结构 D.所有语言 9.到目前为止，计算机中所有的信息任以二进制方式表示的理由是（） A.节约原件 B.运算速度快 C.由物理器件的性能决定 D.信息处理方便 10.冯.诺依曼计算机中指令和数据均以二进制形式存放在存储器中，CPU区分它们的依据是（） A.指令操作码的译码结果 B.指令和数据的寻址方式 C.指令周期的不同阶段 D.指令和数据所在的存储单元 11.计算机系统层次结构通常分为微程序机器层、机器语言层、操作系统层、汇编语言机器层和高级语言机器层。层次之间的依存关系为（） A.上下层都无关 B.上一层实现对下一层的功能扩展，而下一层与上一层无关 C.上一层实现对下一层的功能扩展，而下一层是实现上一层的基础

浅析发射分集与接收分集技术

浅析发射分集与接收分集技术 1 概述 1.1 多天线信息论简介近年来,多天线系统(也称为MIMO系统)引起了人们很大的研究兴趣,多天线系统原理如图1所示，它可以增加系统的容量,改进误比特率(BER).然而,获得这些增益的代价是硬件的复杂度提高,无线系统前端复杂度、体积和价格随着天线数目的增加而增加。使用天线选择技术，就可以在获得MIMO系统优势的同时降低成本。图1 MIMO系统原理有两种改进无线通信的方法：分集方法、复用方法。分集方法可以提高通信系统的鲁棒性，利用发送和接收天线之间的多条路径，改善系统的BER。在接收端，这种分集与RAKE接收提供的类似。分集也可以通过使用多根发射天线来得到，但是必须面对发送时带来的相互干扰。这一类主要是空时编码技术。另外一类MIMO技术是空间复用，来自于这样一个事实：在一个具有丰富散射的环境中，接收机可以解析同时从多根天线发送的信号，因此，可以发送并行独立的数据流，使得总的系统容量随着min( , )线性增长，其中

和是接收和发送天线的数目。 1.2 空时处理技术空时处理始终是通信理论界的一个活跃领域。在早期研究中，学者们主要注重空间信号传播特性和信号处理，对空间处理的信息论本质探讨不多。上世纪九十年代中期，由于移动通信爆炸式发展，对于无线链路传输速率提出了越来越高的要求，传统的时频域信号设计很难满足这些需求。工业界的实际需求推动了理论界的深入探索。在MIMO技术的发展，可以将空时编码的研究分为三大方向：空间复用、空间分集与空时预编码技术，如图2所示。图2 MIMO技术的发展

1.3 空间分集研究多天线分集接收是抗衰落的传统技术手段，但对于多天线发送分集，长久以来学术界并没有统一认识。1995年Telatarp[3]首先得到了高斯信道下多天线发送系统的信道容量和差错指数函数。他假定各个通道之间的衰落是相互独立的。几乎同时， Foschini和Gans在[4]得到了在准静态衰落信道条件下的截止信道容量(Outage Capacity)。此处的准静态是指信道衰落在一个长周期内保持不变，而周期之间的衰落相互独立，也称这种信道为块衰落信道(Block Fading)。 Foschini和Gans的工作，以及Telatar的工作是多天线信息论研究的开创性文献。在这些著作中，他们指出，在一定条件下，采用多个天线发送、多个天线接收(MIMO)系统可以成倍提高系统容量，信道容量的增长与天线数目成线性关系 1.4 空时块编码 (STBC) 本文我们主要介绍一类高性能的空时编码方法——空时块编码( STBC: Space Time Block Code)。 STBC编码最先是由Alamouti[1]在1998年引入的，采用了简单的两天线发分集编码的方式。这种STBC编码最大的优势在于，采用简单的最大似然译码准则，可以获得完全的天线增益。 Tarokh[5]进一步将2天线STBC编码推广到多天线形式，提出了通用的正交设计准则。 2 MIMO原理及方案

金蝶ERP性能测试经验分享

ERP性能测试总结分享

1分享 (3) 1.1测试环境搭建 (3) 1.2并发量计算及场景设计 (3) 1.3测试框架搭建 (4) 1.4测试脚本开发/调试 (5) 1.5场景调试/执行 (5) 1.6性能监控分析 (6) 1.7结果报告 (7) 2展望 (8) 2.1业务调研及场景确定 (8) 2.2场景监控与分析 (8)

1分享 1.1 测试环境搭建在我们进行性能测试之前，通常需要搭建一个供测试用的环境，使用这个环境来录制脚本，根据在这个环境下执行测试的结果，得出最终的测试结论。有些时候，测试环境就是生产环境，例如：一个新的项目上线前进行的性能测试，通常就是在未来的生产环境下进行的。在这种情况下，可以排除测试环境与生产环境差异带来影响，测试结果相对比较准确。反之，如果测试环境与生产环境不是同一环境，这个时候，为了保证测试结果的准确性，需要对生产环境进行调研。在搭建测试环境时，尽量保证搭建的测试环境和生成环境保持一致（环境主体框架相同，服务器硬件配置相近，数据库数据相近等）。另外，最好输出一个测试环境搭建方案，召集各方参加评审确认。同时，在测试方案、测试报告中，对测试环境进行必要的阐述。 1.2 并发量计算及场景设计首先，在确定场景及并发量之前，需要对业务进行调研，调研的对象最好是业务部门，也可以通过数据库中心查询数据，进行辅助。场景选取一般包括：登陆场景、操作频繁的核心业务场景、涉及重要信息（如：资金等）业务场景、有提出明确测试需求的业务场景、组合场景等。每个场景的并发量，需要根据业务调研的结果进行计算。可以采用并发量计算公式：C=nL / T 进行计算（其中C是平均的并发用户数，n是平均每天访问用户数，L是一天内用户从登录到退出的平均时间（操作平均时间），T是考察时间长度（一天内多长时间有用户使用系统））。每个场景的思考时间，也可以通过业务调研获得。另外，也可以采用模拟生产业务场景TPS（每秒通过事务数）的方式，来确定场景。相比上一种方式，模拟生产业务场景TPS，能更加准确模拟生产压力。本次ERP性能测试采用的就是这种方式：首先，通过调研确定业务高峰时段，各核心业务TPS量及产生业务单据量。然后，通过调整组合场景中，各单场景的Vusr（虚拟用户数）和Thinktime（思考时间），使每个场景的TPS接近业务调研所得到的TPS量,每个场景相同时间（即高峰时间段长度）通过事务数接近调研业务单据量，从而确定一个，可以模拟生成环境压力的基准场景。最后，通

计算机组成原理试题及答案

《计算机组成原理》试题一、（共30分） 1.(10分) (1)将十进制数+107/128化成二进制数、八进制数和十六进制数（3分） (2)请回答什么是二--十进制编码?什么是有权码、什么是无权码、各举一个你熟悉的有权码和无权码的例子？（7分） 2.已知X=0.1101,Y=-0.0101,用原码一位乘法计算X*Y=?要求写出计算过程。(10分) 3.说明海明码能实现检错纠错的基本原理?为什么能发现并改正一位错、也能发现二位错，校验位和数据位在位数上应满足什么条件？（5分） 4.举例说明运算器中的ALU通常可以提供的至少5种运算功能?运算器中使用多累加器的好处是什么?乘商寄存器的基本功能是什么?(5分) 二、(共30分) 1.在设计指令系统时,通常应从哪4个方面考虑?(每个2分,共8分) 2.简要说明减法指令SUB R3,R2和子程序调用指令的执行步骤(每个4分，共8分) 3.在微程序的控制器中，通常有哪5种得到下一条指令地址的方式。(第个2分，共10分） 4.简要地说明组合逻辑控制器应由哪几个功能部件组成？(4分）三、（共22分） 1.静态存储器和动态存储器器件的特性有哪些主要区别？各自主要应用在什么地方？（7分） 2.CACHE有哪3种基本映象方式，各自的主要特点是什么？衡量高速缓冲存储器（CACHE）性能的最重要的指标是什么？（10分） 3.使用阵列磁盘的目的是什么？阵列磁盘中的RAID0、RAID1、RAID4、RAID5各有什么样的容错能力？（5分）四、（共18分） 1.比较程序控制方式、程序中断方式、直接存储器访问方式，在完成输入/输出操作时的优缺点。（9分） 2.比较针式、喷墨式、激光3类打印机各自的优缺点和主要应用场所。（9分）答案一、（共30分） 1.(10分) (1) (+107/128)10 = (+1101011/10000000)2 = (+0.1101011)2 = (+0.153)8 = (+6B)16 (2) 二-十进制码即8421码，即4个基2码位的权从高到低分别为8、4、2、1，使用基码的0000，0001，0010，……，1001这十种组合分别表示0至9这十个值。4位基二码之间满足二进制的规则，而十进制数位之间则满足十进制规则。１

端口镜像典型配置举例

端口镜像典型配置举例 1.5.1 本地端口镜像配置举例 1. 组网需求某公司内部通过交换机实现各部门之间的互连，网络环境描述如下： ●研发部通过端口GigabitEthernet 1/0/1接入Switch C； ●市场部通过端口GigabitEthernet 1/0/2接入Switch C； ●数据监测设备连接在Switch C的GigabitEthernet 1/0/3端口上。网络管理员希望通过数据监测设备对研发部和市场部收发的报文进行监控。使用本地端口镜像功能实现该需求，在Switch C上进行如下配置： ●端口GigabitEthernet 1/0/1和GigabitEthernet 1/0/2为镜像源端口； ●连接数据监测设备的端口GigabitEthernet 1/0/3为镜像目的端口。 2. 组网图图1-3 配置本地端口镜像组网图 3. 配置步骤配置Switch C： # 创建本地镜像组。

system-view [SwitchC] mirroring-group 1 local # 为本地镜像组配置源端口和目的端口。 [SwitchC] mirroring-group 1 mirroring-port GigabitEthernet 1/0/1 GigabitEthernet 1/0/2 both [SwitchC] mirroring-group 1 monitor-port GigabitEthernet 1/0/3 # 显示所有镜像组的配置信息。 [SwitchC] display mirroring-group all mirroring-group 1: type: local status: active mirroring port: GigabitEthernet1/0/1 both GigabitEthernet1/0/2 both monitor port: GigabitEthernet1/0/3 配置完成后，用户就可以在数据监测设备上监控研发部和市场部收发的所有报文。

计算机原理试题及答案

计算机组成原理试卷A 一、选择题（每小题2分，共30分） 1．下列数中最小的数是______。 A.（100100）2 B.（43）8 C.（110010）BCD D.（25）16 2．计算机经历了从器件角度划分的四代发展历程，但从系统结构上来看，至今绝大多数计算机仍属于______型计算机。 A.实时处理 B.智能化 C.并行 D.冯.诺依曼 3．存储器是计算机系统中的记忆设备，它主要用来______。 A.存放数据 B.存放程序 C.存放微程序 D.存放数据和程序 4．以下四种类型指令中，执行时间最长的是______。 A.RR型指令 B.RS型指令 C.SS型指令 D.程序控制指令 5. 计算机的外围设备是指______。 A.输入/输出设备 B.外存储器 C.远程通信设备 D.除了CPU和内存以外的其它设备 6．堆栈寻址方式中，设A为通用寄存器，SP为堆栈指示器，M SP为SP指示器的栈顶单元，如果操作动作是：（A）→M SP，（SP）-1→SP，那么出栈操作的动作应为______。 A.（M SP）→A，（SP）+1→SP B.（SP）+1→SP，（M SP）→A C.（SP）-1→SP，（M SP）→A D.（M SP）→A，（SP）-1→SP 7．某寄存器中的值有时是地址，因此只有计算机的______才能识别它。 A.译码器 B.判别程序 C.指令 D.时序信号 8. 寄存器间接寻址方式中，操作数处在______。 A.通用寄存器 B.主存单元 C.程序计数器 D.堆栈 9. 假定下列字符码中有奇偶校验位，但没有数据错误，采用偶校验的字符码是______。 A.11001011 B.11010110 C.11000001 D.1100101 10.不是发生中断请求的条件是______。 A.一条指令执行结束 B.一次I/O操作结束 C.机器内部发生故障 D.一次DMA操作结束 11.指令系统中采用不同寻址方式的目的主要是______。 A实现存贮程序和程序控制B缩短指令长度，扩大寻址空间，提高编程灵活性C可以直接访问外存D提供扩展操作码的可能并降低指令译码难度 12.某SRAM芯片，其容量为512×8位，除电源和接地端外，该芯片引出线的最小数目应是______。 A 23 B 25 C 50 D 19 13.算术右移指令执行的操作是______。 A 符号位填0，并顺次右移1位，最低位移至进位标志位；

端口镜像配置

的需要，也迫切需要

例如，模块1中端口1和端口2同属VLAN1，端口3在VLAN2，端口4和5在VLAN2，端口2监听端口1和3、4、5， set span 1/1，1/3-5 1/2 2950/3550/3750 格式如下： #monitor session number source interface mod_number/port_number both #monitor session number destination interface mod_mnumber/port_number //rx-->指明是进端口得流量，tx-->出端口得流量 both 进出得流量 for example: 第一条镜像，将第一模块中的源端口为1-10的镜像到端口12上面； #monitor session 1 source interface 1/1-10 both #monitor session 1 destination interface 1/12 第二条镜像，将第二模块中的源端口为13-20的镜像到端口24上面； #monitor session 2 source interface 2/13-20 both #monitor session 2 destination interface 2/24 当有多条镜像、多个模块时改变其中的参数即可。 Catalyst 2950 3550不支持port monitor C2950#configure terminal C2950(config)# C2950(config)#monitor session 1 source interface fastEthernet 0/2 !--- Interface fa 0/2 is configured as source port. C2950(config)#monitor session 1 destination interface fastEthernet 0/3 !--- Interface fa0/3 is configured as destination port. 4配置命令 1. 指定分析口 feature rovingAnalysis add，或缩写 f r a，例如： Select menu option: feature rovingAn alysis add Select analysis slot: 1?& nbsp; Select analysis port: 2 2. 指定监听口并启动端口监听 feature rovingAnalysis start，或缩写 f r sta，例如： Select menu option: feature rovingAn alysis start Select slot to monitor ?(1-12): 1 Select port to monitor&nb sp;?(1-8): 3

CS架构性能测试

C/S测试通常，客户/ 服务器软件测试发生在三个不同的层次： 1.个体的客户端应用以“ 分离的” 模式被测试——不考虑服务器和底层网络的运行； 2.客户端软件和关联的服务器端应用被一起测试，但网络运行不被明显的考虑； 3.完整的 C/S 体系结构，包括网络运行和性能，被测试。下面的测试方法是 C/S 应用中经常用到的：应用功能测试客户端应用被独立地执行，以揭示在其运行中的错误。服务器测试——测试服务器的协调和数据管理功能，也考虑服务器性能（整体反映时间和数据吞吐量）。数据库测试——测试服务器存储的数据的精确性和完整性，检查客户端应用提交的事务，以保证数据被正确地存储、更新和检索。事务测试——创建一系列的测试以保证每类事务被按照需求处理。测试着重于处理的正确性，也关注性能问题。网络通信测试——这些测试验证网络节点间的通信正常地发生，并且消息传递、事务和相关的网络交通无错的发生。 C/S结构与B/S结构的特点分析为了区别于传统的C/S模式，才特意将其称为B/S模式。认识到这些结构的特征，对于系统的选型而言是很关键的。 1、系统的性能在系统的性能方面，B/S占有优势的是其异地浏览和信息采集的灵活性。任何时间、任何地点、任何系统，只要可以使用浏览器上网，就可以使用B/S系统的终端。不过，采用B/S结构，客户端只能完成浏览、查询、数据输入等简单功能，绝大部分工作由服务器承担，这使得服务器的负担很重。采用C/S结构时，客户端和服务器端都能够处理任务，这虽然对客户机的要求较高，但因此可以减轻服务器的压力。而且，由于客户端使用浏览器，使得网上发布的信息必须是以HTML 格式为主，其它格式文件多半是以附件的形式存放。而HTML格式文件（也就是Web页面）不便于编辑修改，给文件管理带来了许多不便。

计算机原理-答案

《计算机原理》答案一、填空题 1、1024 1024 1024 2、运算器、控制器、存储器、输入设备、输出设备 1、内存储器外存储器 2、打字键区_、功能键区、游标/控制键区__、数字键区_ 3、处理器、文件、存储器、作业、 4、多任务、图形界面 5、您的计算机进入睡眠状态、关闭计算机、重新启动计算机和重新启动计算机并切换到 MS___DOS方式（M）。 6、两 7、三 8、用户的帐号 9、不同性质的概念二、简答题 1、简述计算机的工作原理。计算机仅有硬件，计算机只有运算的可能性，如果计算机进行计算、控制等功能的话，计算机还必须配有必要的软件。所谓软件就是指使用计算机的各种程序。(1)指令和程序的概念指令就是让计算机完成某个操作所发出的指令或命令，即计算机完成某个操作的依据。一条指令通常有两个部分组成，前面是操作码部分，后面是操作数部分。操作码是指该指令要完成的操作，操作数是指参加运算的数或者数所在的单元地址。一台计算机的所有指令的集合，称为该计算机的指令系统。使用者根据解决某一问题的步骤，选用一条条指令进行有许的排列。计算机执行了这一指令序列，便可完成预定的任务。这一指令序列就称为程序。显然，程序中的每一条指令必须是所用计算机的指令系统中的指令，因此指令系统是系统提供给使用者编制程序的基本依据。指令系统反映了计算机的基本功能，不同的计算机其指令系统也不相同。 (2)计算机执行指令的过程计算机执行指令一般分为两个阶段：第一阶段，将要执行的指令从内存取到CPU内；第二阶段，CPU对屈辱的该指令进行分析译码，判断该条指令要完成的操作，然后向各部件发出完成该操作的控制信号，完成该指令的功能。当一条指令执行完后就进入下一条指令的取指操作。一般将第一阶段取指令的操作称为取指周期，将第二阶段称为执行周期。 (3)程序的执行过程程序是一系列指令的有序集合构成，计算机执行程序就是、执行这系列指令。CPU从内存读出一条指令到CPU执行，该指令执行完，再从内存读出下一条指令到CPU内执行。CPU 不断取指令，执行指令，这就是程序的执行过程。 2、计算机有哪些应用领域？目前，电子计算机已经在工业、农业、财贸、经济、国防、科技及社会生活的各个领域中得到极其广泛的应用。归纳起来分以下几个方面。科学计算数据处理自动控制计算机辅助工程人工智能 3、什么是操作系统？操作系统是计算机软件系统的核心和基础，它提供了软件开发和运行的环境。有了操作系统，计算机的各个部件才得以协调工作，得到有效管理。 4、文档是如何创建、关闭和打开的？其内容是如何进行复制、删除和移动的？创建；在WORD窗口中选择文件菜单中的新建，即可新建一个文档关闭：所谓关闭文档，即对当前文档存盘并退出对该文档的处理，只需要在文件菜单中选择关闭命令，或者用鼠标单击文档窗口右上角的关闭按钮。如果关闭文档之前尚未保存文档，则系统会给出提示，询问是否保存对该文档的修改。打开；（1）在WINDOWS的资源管理器中或我的电脑窗口中找到需要打开的WORD文档，然后

沙发性能测试

1. 作用家具性能测试是一种加速使用的疲劳和强度承受能力的测试方法，可以用来评估产品能否达到预期的设计要求。 2.GSA沙发性能测试 2.1 测试方法 GSA性能测试基于循环递增加载模式（图1）。测试开始时先给沙发加一个起始载荷，这个载荷以20次/分的频率循环加力25000/次。循环结束后，载荷增加一定量，然后再循环25000次。当载荷达到所需求的水平，或沙发框架或部件破环时测试才结束。 2.2测度设备 GSA沙发性能测试是在一套特别设计的汽缸-管道支架系统上进行的（如照片所示）。气缸在压缩空气机的推动下，以20次/分的循环频率对被测沙发加载。加载循环次数是由一个可编程逻辑控制器和可重置电子记数系统进行记录的。当沙发框架或部件破坏时，限制开关被激活并停止测试。 2.3主要的测试类型图2所示是沙发的基本框架图，沙发框架可以分成3个部分：坐基框架系统、侧边扶手框架系统和后靠框架系统。根据沙发通常的受力状态，可以进行以下几种测试： 3 测试数据的讨论 3.1垂直坐力测试（seat foundation load test）（图3），在垂直坐力作用下，主要的座位支撑框架部位承受很大的应力，如果其中任何一个部件破坏，整个沙发也就很快破坏了。前横档和后横档破坏的主要原因是其尺寸大小，不过实木横档上有太多交叉纹理和太大太多的节疤刀会引起横档破坏。横档底部的节疤破坏性最大，因为这里所受的拉应力最大，如果支撑框架部件主要是由木榫钉为主要连接件，横档破坏常常起于横档上用于连接座位撑档的榫钉孔处，然后扩大到整个横档截面上。另外在测试中，前横档和前支柱的接头也经常是破坏发生的地方，既有在垂直面的破坏，也有前后方向的破坏。这些破坏的接头大多是由于没有加用涂胶支撑木块来加强连接，而

Hybrid electric vehicles and their challenges_ A review

Web性能测试方案

计算机原理试题与答案

h3c端口镜像配置及实例

品质体系框架图.

天线分集技术的原理

性能测试流程规范

计算机组成原理试题及答案

华为交换机端口镜像配置举例

计算机组成原理参考答案汇总

浅析发射分集与接收分集技术

金蝶ERP性能测试经验分享

计算机组成原理试题及答案

端口镜像典型配置举例

计算机原理 试题及答案

端口镜像配置

CS架构性能测试

计算机原理-答案

沙发性能测试

计算机原理试题及答案