Final Project: Design of an Electric Vehicle

Create a MATLAB model of electric car which uses a battery and a DC motor. Choose suitable blocks from Powertrain block set. Prepare a report about your model including following:

Objectives:

1. System level configurations

2. Model parameters

3. Results

4. Conclusion

PROJECT: DESIGN OF AN ELECTRIC VEHICLE

Theory:

An electric vehicle(EV) is defined as a vehicle that uses an electric motor or a traction motor for propulsion instead of internal combustion used by conventional vehicles. Electric vehicle use electricity for power instead of fossil fuels like conventional vehicles . So, they do not produce any exhaust gases and pollution. The power needed in the EV come from batteries, generator or any collector system. Batteries fitted in the EV are of high energy densities in order meet the power requirements and range.

The power of a vehicle's electric motor, as in other vehicles, is measured in kilowatts (kW). 100 kW is roughly equal to 134 horsepower but electric motors can deliver their maximum torque over a wide RPM range. This means that the performance of a vehicle with a 100 kW electric motor exceeds that of a vehicle with a 100 kW internal combustion engine, which can only deliver its maximum torque within a limited range of engine speed. Energy is lost during the process of converting the electrical energy to mechanical energy. Approximately 90% of the energy from the battery is converted to mechanical energy, the losses being in the motor and drivetrain.Usually, (DC) electricity is fed into a DC/AC inverter where it is converted to (AC) electricity and this AC electricity is connected to a 3-phase AC motor. For electric trains, and some electric cars, DC motors are often used. In some cases, universal motors are used, and then AC or DC may be employed. In recent production vehicles, various motor types have been implemented; for instance, induction motor within Tesla Motor vehicles and permanent magnet machines in the Nissan Leaf and Chevrolet Bolt.

Most large electric transport systems are powered by stationary sources of electricity that are directly connected to the vehicles through wires. Electric traction allows the use of Regenerative braking, in which the motors are used as brakes and become generators that transform the motion of, usually, a train into electrical power that is then fed back into the lines. This system is particularly advantageous in mountainous operations, as descending vehicles can produce a large portion of the power required for those ascending. This regenerative system is only viable if the system is large enough to utilise the power generated by descending vehicles. In order for EV,s to dominate the automotive industries, Their needs to be more convinient ways for consumers to be able to charge their vehicles. There needs to be several charging stations on highways and this can be supported if most of the houses are solar powered. EV,s cost more than conventional vehicles because of the high cost of batteries and electric components.

HEV's combine an IC engine with an electric propulsion system to produce a hybrid between the two types of vehicles. The purpose of this is to use the power available from the electric power-train to improve the fuel economy of the vehicle so that it does not rely solely on the petrol/diesel for the fuel. This in turn will also improve the overall performance of the HEV. The IC engine can be used to power the electric motor to charge the battery oruse directly in the electric drive motor with acombination of motor and generator in one. HEV's also implement regenerative braking to recharge their batteries . EV's are still a relatively new technology and account for 2-3%of the world wide market. Whereas HEV's represent more of the market with 19% market share on all automobiles. The all time best selling HEV to date is the toyota prius.

In this report , I will be modelling an electric vehicle with a DC motor and battery system using the SIMULINK software. The model will run for a drive-cycle and measure the velocity characteristics, current, and state of charge characteristics of the battery system. The components i need to exist as blocks in the simulink block library.

AIM

To create a MATLAB model of electric car which uses a battery and a DC motor using Power train block set.

OBJECTIVE

To model an electric car in MATLAB using Power train block set and prepare a report including following:

1. System level configurations
2. Model parameters
3. Results
4. Conclusion

DESIGN CALCULATIONS

To model the EV, we have to calculate certain parameters like, Power, Energy, Range, Motor Rating, Battery Capacity etc. For Vehicle dimension data, let’s refer TATA NEXON EV Spec. which is given below.

TATA NEXON EV – Specifications

Power	95kW
Length (mm)	3993
Width (mm)	1811
Height (mm)	1606
Tire Dimension	664.4mm
Kerb Weight (Kg)	1400
Battery Capacity	30.2kWh
Motor Ratings (3phase PMSM)	97.46kW, 245Nm
Range	312km

Table 1: TATA Nexon Specifications

In order to find the motor ratings, Battery capacity, Maximum power, Torque and Energy required by the vehicle, we have to create a model first for the design of Electric vehicle.

To calculate the parameters of the vehicle, let’s first choose the drive cycle.

Drive cycle

The WLTP procedure (world harmonized light-duty vehicles test procedure) is a harmonized standard for determining the levels of pollutants, CO₂ emissions and fuel consumption of traditional and hybrid cars, as well as the range of fully electric vehicles.

The WLTP procedure relies on the new driving cycles (WLTC – Worldwide harmonized Light-duty vehicles Test Cycles) to measure the mean fuel consumption, the CO₂ emissions as well as the emissions of pollutants by passenger cars and light commercial vehicles.

The test procedure WLTP (Worldwide harmonized Light vehicles Test Procedure) contains several driving cycles:

• Class 1 – low power vehicles with PW_r <= 22
• Class 2 – vehicles with 22 < PW_r <= 34
• Class 3 – high-power vehicles with PW_r > 34

Where PW_r [kW/Tonne] is the power-to-weight ratio, defined as the ratio between the rated engine power and kerb weight.

PWr=Pmax/mv

Since we are modeling TATA Nexon EV, Let’s take parameters from Table 1.

Pmax =95kW , Kerb Weight = 1.4 Tonnes

PWr= 95/1.4 = 67.85

Since the vehicle’s PW_r is bigger than 34, we are going to use the WLTC Class 3 driving cycle to calculate the energy consumption.

WLTC Class 3

The WLTP is divided into 4 different sub-parts, each one with a different maximum speed:

• Low, up to 56.5 km/h
• Medium, up to 76.6 km/h
• High, up to 97.4 km/h
• Extra-high, up to 131.3 km/h.

These driving phases simulate urban, suburban, rural and highway scenarios respectively, with an equal division between urban and non-urban paths (52% and 48%).

Figure 1: WLTC Class 3b Driving Cycle

Force Calculation

The forces acting on the vehicle are as follows.

Rolling Resistance = m*g*Cr*cos(alpha) = 1000*9.81*0.02*cos(1)

Aerodynamic drag = 0.5*Cd *Af*Ad*V^2 = 0.5* 0.33*2.34*1.25*V^2

Grade Resistance = m*g*sin(beta) = 1000*9.81*sin(10)

Acceleration resistance = m*a = 1000*(Velocity difference)

Total force = Sum of all the above forces.

Power = Total Force * Velocity

Torque = Power * Wheel radius

Energy = 1/s (Power)

The above calculations can be modeled in Simulink as shown below.

Figure 2: Modeling Forces and calculating Torque, Enegy and Power

Figure 3: Vehicle Model in Simulink

By dividing the last calculated value of the total energy to the total length of the WLTC drive cycle (23.266 km), we get the average energy consumption of the vehicle, 160 Wh/km.

Figure 4: Power Curve of Vehicle

The above plot gives the power required by the vehicle at different speeds of drive cycle. From the plot we can understand that in order to achieve maximum speed of 131km/hr, the motor should be rated with 140kW. But due to size and cost constraint we cannot choose the high rated motor. We should select in such a manner that the motor operated at maximum efficiency during average speed.

Figure 5: Torque Curve

From the above plot, we can understand that the maximum required torque is 222Nm.

Motor Capacity Selection

Form the Torque and power plots we can select the motor required for our Electric Car. As we are modeling TATA Nexon, we can choose BLDC motor with 95.8kW, 279Nm.

The Parameters of Motor from figure 6 can be summarized in the table below.

Rated Power	95.8 kW
Rated Torque	279Nm
Rated voltage	460V
No load Speed	3280rpm
Rated Speed	4000rpm
Armature Inductance	2mH

Table 2: Motor Ratings

Figure 6: Motor Rating

Battery Capacity Calculations [2],[3]

We have calculated the average energy consumption for propulsion E_p as being 160 Wh/km on WLTC drive cycle. On top of the energy needed for propulsion, the high voltage battery must supply the energy for the vehicle’s auxiliary devices E_aux [Wh/km], like: 12 V electrical system, heating, cooling, etc. Also, we have to consider the efficiency of the powertrain η_p during the conversion from electrical energy to mechanical energy.

Eavg=(Ep+Eaux)/ η_p (1)

The prolonged electrical loads (headlights, multimedia, etc.) and intermittent loads (heater, brake lights, wipers, etc.) use on average 430 W of electrical power. The duration of the WLTC cycle is 1800 s (0.5 h), which gives an energy of 215 Wh for the auxiliary loads. If we divide it to the length of the WLTC driving cycle (23.266 km), we get an average energy consumption for the auxiliary loads E_aux of 9.241 Wh/km.

Even if Wh/km is not really energy but factorised energy, since it’s dived per unit of distance (km), for simplicity, we are going to refer to it as average energy.

The direct current (DC) supplied by the battery is converted into alternated current (AC) by the inverter. This conversion is taking place with an associated loss. Also, the electric motor and driveline have some losses which we need to consider. For this exercise we are going to use an average efficiency η_p of 0.9 from the battery to the wheel.

Replacing the values in (1) gives the average energy consumption:

Eavg=(160+9.241)/0.9=188.045 Wh/km

The battery pack will be designed for an average energy consumption of 188.045 Wh/km.

The required battery pack total energy E_bp [Wh] is calculated as the product between the average energy consumption E_avg [Wh/km] and vehicle range D_v [km]. For this example we’ll design the high voltage battery pack for a vehicle range of 250 km.

Ebp=Eavg * Dv=188.045 * 250 = 47,011.25 Wh=47.011 kWh (2)

The following calculations are going to be performed for each cell type. For this example we are going to consider that the battery pack is made up only from several strings connected in parallel.

The number of battery cells connected in series (N_cs) in a string is calculated by dividing the nominal battery pack voltage U_bp [V] to the voltage of each battery cell U_bc [V]. The number of strings must be an integer. Therefore, the result of the calculation is rounded to the higher integer.

Ncs = Ubp * Ubc = 460 / 3.6 = 128 (3)

The energy content of a string E_bs [Wh] is equal with the product between the number of battery cells connected in series N_cs and the energy of a battery cell E_bc [Wh].

Ebs = Ncs * Ebc = 128 * 11.52 = 1474.56Wh (4)

The total number of strings of the battery pack (N_sb) is calculated by dividing the battery pack total energy E_bp [Wh] to the energy content of a string E_bs [Wh]. The number of strings must be an integer. Therefore, the result of the calculation is rounded to the higher integer.

Nsb=Ebp / Ebs = 47011.25 / 1474.56 = 32 (5)

We can now recalculate the battery pack total energy E_bp [Wh] as the product between number of strings N_sb and the energy content of each string E_bs [Wh].

Ebp=Nsb*Ebs = 32*1474.56 = 47185.92 Wh (6)

The battery pack capacity C_bp [Ah] is calculated as the product between the number of strings N_sb and the capacity of the battery cell C_bc [Ah].

Cbp = Nsb*Cbc = 32 * 3.2 = 102.4 Ah (7)

The total number of cells of the battery pack (N_cb) is calculated as the product between the number of strings N_sb and the number of cells in a string N_cs.

Ncb = Nsb*Ncs = 32*128 = 4096 (8)

The Battery Parameters can be summarized in the following table.

Vehicle Range	250 km
Average Energy Consumption	188.045 Wh/km
Nominal voltage of single cell	3.6V
Capacity of single cell	3.2Ah
Energy of a single cell	11.52Wh
No. of cells in a string	128
No. of Strings	32
Total no.of cells	4096
Nominal Battery Voltage	460V
Energy of Battery pack	47.19kWh
Power of battery pack	47.10kW
Battery Current	102.40A
Capacity of Battery pack	102.40Ah

Table 3: Battery Ratings

SIMULINK MODELLING OF COMPLETE ELECTRIC VEHICLE

The Complete model of Electric vehicle in Simulink is as shown below in figure 7.

COMPONENTS:

The main components of the EV are:

• Wheels/tires
• Battery
• Motor/generator
• Motor controllers
• Power converters
• Transmission system

Main simulation diagram:

In the below picture , we have done the simulation of an electric vehicle using various drive cycles by using powertrain blockset available in simulink library.First, there is the inputs where we have connected two different drive cycles which provides the reference for the longitudinal driver which compares the two speed and gives accelerator and braking commands to the motor controller block. battery block and vehicle body blocks are further attached and scopes are used for displaying the working status.

System level configuration:

For modelling the whole vehicle in SIMULINK. we need to model the above emntioned components separately and make them work together>.All the main components are available in the library of SIMULINK blocks. so we add components and configure the parameters to fit the the working requirements of the model.

Vehicle body:

This block contain 6 ports which can be used to model various aspects of the vehicle body. The ports are mentioned below;

• H- This stands for hub and is used to connect the hubs of the wheels to the main body of the vehicle.
• V-Physical signal output port which stands for 'velocity' and is used the output the velocity of the vehicle.
• W- Physical signal input port and allows us to model a wind velocity that acts aginst the vehicle.
• NR- Physical signal output port to connect to connect the rear wheels
• NF- Physical signal output port to connect the front wheels of the vehicle.
• Beta- Physicall signall input port which allows the vehicle to undergo an inclination of hill climbing force.
• Model parameters to set up mass, frontal area amd others.

VEHICLE BODY SUBSYSTEM:

The above blocks are forming a subsystem which serves as a part for the whole vehicle. Four tires are connected, where the right two tires are the rear wheels and the remaining two are the front wheels . they are interconnected to the hub of the vehicle body block. and their respective axles are connected accordingly. We here have connected the rear axle with the gear as we want the model to be a rear wheel drive vehicle. Here the wind velocity port and hill-climbing angle ports are connected to physical constant blocks which is kept as zero.

Tire block parameters:

Here we can also change the geometry , dynamics, rolling resistance other characteristics if we want

Simple gear block parameters:

This block models a gear system with fixed gear ratio with no-inertia effects. However, we can modify the messing of the gear teeth, Here The follower to base teeth ratio has been set to 2 and the output shaft rotates in the same direction as the input shaft.

All these blocks are categorised into a single subsystem which we have names as vehicle body block, which takes the mechanical input from the motor and controller block into the gear and displays the velocity at which the vehicle body moves.

MOTOR AND CONTROLLER SUBSYSTEM:

Components:

• DC Motor
• H-bridge
• Controlled PWM voltage
• Controlled voltage source
• Current sensor

DC-Motor-

For the EV model, I have selected to use a DC motor block because DC motors are easy to model and have a very few parameters to run for a particular application. There are two sides of the block , the mechanical side is on the right and the electrical side is on the left. mechanical side has tow ports C and R, C stands for casing and is the stable part and R is the rotor which produces a torque. The electrical side has a positive and negetive side for the voltages to be applied. If positive voltage is applied to the motor block from the positive to the negetive terminal then a positive torque will act from C to R port. The directio of the torque can be cahnged by changing the sign of the back emf or the torque constant. Here i have connected the c port to the mechanical rotational reference because it will be stationary. The R port is connected to the gear in the vehicle body block.

Here i have choosen to parameterize the block by rated power, rates speed and no-load speed. This lets us modify the parameterssuchas DC supply voltage, rated load. I have kept all values default except for the no-load speed, rated speed and rated load.

H-bridge:

This is a power converter which is needed to provide power of the correct form and magnitude from one component to other. In case of EV,s a power converter is needed to provide a DC voltage from the battery of the EV to the DC motor, so that it can fuction properly at the required parameters.Here i have used an H-bridge motor drive as my power converter. The left side is for controlling the voltage signalsand the right side terminals to provide the controlled voltage to the DC motor the left side ports are:

• PWM- Pulse width modulation
• REF- Reference
• REV- Reverse
• BRL- Brake

The simulation is kept in average mode beacuse PWM mode will take longer durations of simulation. In the section of bridge parameters the output voltage amplitude was modified to 400 volts according to the DC motor.

Controlled Pwm voltage :

Next, i have used a 'controlled PWM voltage' to provide a controlled pulse width modulated voltage to the H-bridge block. The pulses of voltage created by this block are dependent on the duty cycle which is in that ratio of the time that the switch is ON to the time taken for one cycle. The duty cycle formula is given by:- Duty cycle= Ton/Ton +Toff= Ton /Tcyc. where Ton = On time,Tcyc=Time taken for one cycle.

Here all the parameters are set to their default values. I have chosen the averaged simulation mode so that it will feed voltage pulses within quicker simulation times to the H-bridge. The remaining parameters of input scaling and output scaling are unchanged.

Controlled voltage source:

This block provides the necessary voltage that is powerfull enough to maintaion thr voltage at the output regardless of the current that passes through it.In this subsystem @ control voltage blocks ahve been used . One block is used for acceleration and other to provide the voltage for deacceleration.

Electrical reference block is used to create grounding effect for electrical circuits. In my model, we have used it in 2 parts . First to create an electrical ground between Controlled voltage source, controlled PWM voltage, H-bridge blocks. The second is for the battery system which will be modelled afterwards.

Solver configuration block is used to solve any necessary equations in a model. I Have used them in the connection to the REV port of the H-Bridge block.

Battery Subsystem:

Battery: The battery will be the energy store of the EV and will contain the electrical energy in DC form and provide this energy to operate.

Nominal voltage has been set to 600 volts, internal resistance has been set to 0.2 ohms and an infinite charging capacity

Nominal voltage is sufficient for supplying the voltage to DC-motor andH-bridge blocks.

Controlled current source:

This block is a part in the battery sub-system. Similar to voltage source, this block produces an ideal current that is powerfull enough to maintain the specified current regardless of the voltage across it.

Current source:

This current sensor block represents an ideal current sensor and is used to convert the current measured in an electrical circuit to a physical signal that is proportional to the current. It measures the current in the battery circuit and the DC motor. The positive and negetive terminals across which thecurrent sensor is inserted in to the circuit. The third port outputs the physical signal , In my model it sends the signal to te controlled current source.

SOC (state of charge) estimate subsystem:

To measure the state of charge of the battery, a sub-system was created of various blocks. The first block is integrator block used to handle data transfer and integrate the value of the current signal with respect to time and next is the Gain block is used in order to multiplyer divide the signal coming from integrator block. This block will divide the current signal with the ampere ratingof battery which is 140(Ah)*3600(secs in hour) . Assuming the battery is always fully charged I have added the constant block with a value of 1 representing 100%.Next a sum block is used to perform addition and substraction operations athese blocks aremade into a subsystem called SOC estimate. A scope block is used at the junction of the PS-simulink converter block to plot the output signall of the current from the battery.

Block parameters of the gain block:

Speed measurement :

In order to measure tyhe speed. I have modified the scope block to have two input ports where one port takes the output velocity signal from the vehicle sub-system block and other port takes the output signall from the drive cycle to the reference velocity port on the longitudinal driver block. This has been done to compare the two speeds and check weather they overlap and achieve the same speed.

Distance measurement:

Mathematical blocks and scope block is used to measure the distance travelled by the vehicle. First we had to implement the integrator block to integrate the velocity siganal that is output from the velocity sub-system. Dividen block along with constant block having a value of 3600 is used to divide the integrated speed . This will give us the distance travelled in kilometers.

Longitudional driver and drive cycle:

The longitudinal driver block is used for giving normalized acceleration and deacceleration commants to a controller based on two sets of data. The first data is the reference velocity and second data is the feedback velocity.The reference velocity data coming from drive cycle source and is compared to the feedback velocity data coming from the vehicle body. If the reference velocity is greater than the feedback velocity, an acceleration comand will be given as an output to the controlled voltage source. If the reference velocity is lesser than the feedback velocity, a deacceleration command is given as output to anpother controll voltage source. For the output acceleration and deacceleration commands i have used simulink-PS converter block. In this case the input signal; is velocity data and this is logic data which have to be converted to a voltage signal The ports in this block are:

• Velref- This stands for the reference velocity and it is the velocity data provided from a drive cycle source.
• Velfdbl- This stands for feedback velocity and it is coming from the vehicle's body velocity port
• Grade- This port provides a grade or inclination angle on which the vehicle is travelling in degrees.
• Info- This port is for the bus signals which consists of block calculations
• Accelcmd- This port provides the acceleration command to a controlled voltage source
• Deacclcmd- This port provides the deacceleration command to another voltage source.

Drive cycle:

A drive cycle is a data set that contains velocity and time data for the purpose of modelling the motion of a vehicle. It is a plot of the vehicle velocity against the time and it is made to resembl typicall driving conditions that a consumer may experience themselves in. For example here i have used two types of drive cycle data one is the 'newyork bus cycle' and other is the 'artemis motorway of 150kmph'. Drive cycles are used by various testing procedures such as mileage, pollution tests, and acceleration and top speed tests.There are three ways of implementing a drive cycle. One method is to create your own drive cycle with spreedsheet or excelsheet. Another method isuse a signal builder and create siganls according to the user and the method that we used is to implement industry standard drive cycles which are previosly used to test parameters of the vehicle.

Block parameters:

Artemis Motorway 150kmph Drive cycle graph is given as input to the vehicle model-

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Results: I ran the above drive cycle for my EV model and took the outputs given from speed, surrent and SOC scopes. The distance travelled by the vehicle in the drive cycle is also measured using the display block. Before simulation the run time was updated according to the drive cycle time 1068secs.

Speed scope:

From this scope we can see two signals. The blue signal represents the vehicles body speed and the yellow signal is the Artemis drive cycle data . As we can see that the longitudinal driver successfully maintains the drive cycle data , process it and controls the vehicle's speed according to the reference speed. the graph overlaps eachother effectively during acceleration and deacceleration.

Current scope:

This scope shows how current flowing from the battery to the motor varies with the drive cycle.

SOC scope:

The SOC scope shows how the state of the battery varies over the drive cycle time, The batter was modelled to begin with an SOC pf 1 that is 100%. As the simulation starts the charge of the bettery gets decreased and when the vehicle is in braking mode the uplift in the grapf shows that regenerative braking is working to maintain the battery charge. Here we can see that after the whole simulation is over the State of charge percent lies at 75% after 1068 secs.

Figure 19: Battery Parameters

The nominal voltage of the battery is set as 460V which is same as that of motor rated voltage. The battery rating is given as per Table 3 data.

Figure 20: Battery SOC Estimation

In order to determine State Of Charge of the battery, we can use coulomb counting method.

In this method we are subtracting the charge taken from the battery to the initial SOC.

SOC(t) = SOC(t-1) – (I*t) / AH

The above equation can be modelled in simulink as figure 20.

6. Vehicle Model

Figure 21: Vehicle Model

The vehicle model subsystem consists of the following blocks.

1. Vehicle body
2. Tire
3. Gear

• Vehicle Body

Two-axle vehicle with longitudinal dynamics and motion and adjustable mass, geometry, and drag properties.

Library: Simscape / Driveline / Tires & Vehicles

The Vehicle Body block represents a two-axle vehicle body in longitudinal motion. The vehicle can have the same or a different number of wheels on each axle. The vehicle wheels are assumed identical in size. The vehicle can also have a center of gravity (CG) that is at or below the plane of travel.

The block accounts for body mass, aerodynamic drag, road incline, and weight distribution between axles due to acceleration and road profile. Optionally include pitch and suspension dynamics. The vehicle does not move vertically relative to the ground.

Figure 22: Vehicle body

Figure 23: Block Parameters of Vehicle body

The values of Mass, Frontal area, drag coefficient values given in the vehicle body are from table 1, TATA NEXON specifications.

• Tire

Tire with longitudinal behaviour given by Magic Formula coefficients.

Library:

Simscape / Driveline / Tires & Vehicles

The Tire (Magic Formula) block models a tire with longitudinal behaviour given by the Magic Formula, an empirical equation based on four fitting coefficients. The block can model tire dynamics under constant or variable pavement conditions.

Figure 24b: Tire Parameters

I’ve chosen Load dependent magic formula coefficients. The tire inertia and rolling radius values have been taken from Table 1 Tata NEXON Specifications.

• Gear

Simple gear of base and follower wheels with adjustable gear ratio, friction losses, and triggered faults. It can be accessed from the following libaray.

Library: Simscape / Driveline / Gears

The Simple Gear block represents a gearbox that constrains the connected driveline axes of the base gear, B, and the follower gear, F, to co rotate with a fixed ratio that we specify. We can choose whether the follower axis rotates in the same or opposite direction as the base axis. If they rotate in the same direction, the angular velocity of the follower, ωF, and the angular velocity of the base, ωB have the same sign. If they rotate in opposite directions, ωF and ωB have opposite signs.

Figure 25: Gear Parameters

RESULT ANALYSIS

The distance covered by the vehicle can be found from the block given below. By integrating the vehicle velocity we will get the distance covered. The velocity is in km/hr and the integration time is in seconds. So we have to multiply the displacement by a 1/3600 to convert it in to hours. Then the answer we are getting will be distance in km.

Figure 26: Distance Covered by the Vehicle

The distance covered by the vehicle in WLTP Class 3 drive cycle is 23.27km.

Figure 27: Drive cycle and Vehicle speed plot

The above figure shows the drive cycle speed and vehicle speed plot. We can see that vehicle follows drive cycle in all regions. Slight variations in the curve are in the regions of sudden braking. This may be due to the inertia of the tires.

Figure 28: Acceleration and Deceleration plot

The acceleration and brake signals developed by longitudinal driver is shown above.

Figure 29: PWM Signal to the H-Bridge

The PWM signal generated according to control signals given is shown above. The magnitude of the signal varies with required speed. During maximum speed, the magnitude is maximum and during braking, magnitude is zero.

Figure 30: Battery SOC plot

The State Of Charge plot of the battery is given above. From the plot we can understand that during acceleration, battery is discharging and during braking battery is charging due to regenerative braking enabled in H-bridge. By the end of trip, the SOC has reached 82%.

Results: I ran the above drive cycle for my EV model and took the outputs given from speed, surrent and SOC scopes. The distance travelled by the vehicle in the drive cycle is also measured using the display block. Before simulation the run time was updated according to the drive cycle time 1068secs.

From the above image the display block measured the distance as 8.306kms in 1068secs and charge remaining 75%.

Google drive link of model:https://drive.google.com/file/d/1Ob71v6PquTDBgnWgkauNuXjbBDz6Kw1_/view?usp=sharing

Conclusion:

The EV model has been created with necessary block components using the SIMULINK software and the model have been simulated for an industrial drive cycle "Artemis motorway 150kmph" The simulation has produced the results of the velocity of the vehicle, current flowing from the battery and state of charge as well as the distance travelled in the simulation time. The EV model was able to follow the commands given byreference velocities from the drive cycle data. The distance travelled by my EV model was 8.306kms and seems to be appropriate value based on the artemis motorway drive cycle. The soc of the battery was discharged efficiently upto 75% from full charge. This model has also included some features like regenerative braking which was evident in the current scope and state of charge scope. My Ev model has been attacted to this report as an slx file version R2019a.

MATLAB model of electric car has been created and driver, vehicle and motor parameters were analysed. The design consideration for electric has been analysed with equation based simulink model. Motor rating and battery rating have chosen from datasheet based on calculations in the model. We could also analyse the vehicle velocity and SOC of battery plot.

REFERENCES

1. Tom Denton, Automobile Electrical and Electronic Systems, Third edition. Elsevier Butterworth-Heinemann, 2004, page 129.
2. https://x-engineer.org/automotive-engineering/vehicle/electric-vehicles/ev-design-battery-calculation/#:~:text=The%20total%20battery%20pack%20voltage,sum%20of%20their%20individual%20voltage.&text=In%20order%20to%20increase%20the,to%20be%20connected%20in%20parallel
3. https://x-engineer.org/automotive-engineering/vehicle/electric-vehicles/ev-design-energy-consumption/
4. LSK DC motors specifications

ATTACHMENTS

1. Model_EV3 (Simulink model of EV)
2. EV_car_design (Simulink model for car design parameters)