Final Project: Design of an Electric Vehicle

LIVE SESSION BATCH (MATLAB TRAIL VERSION)

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:

ANSWER:-

Electric vehicle:-

• Electric vehicle (EV) is defined as a vehicle that uses an elect ric motor or a traction motor for propulsion unlikely to an internal combustion (lC) engine used by conventional vehicles.

• Electric vehicles use electric power instead of fuels as convent on all vehicles would and because of this difference, electricvehicles do not produce any exhaust gases or pollution(Zero emission).

• The power needed forthe operation of an EV can come from a variety of sources such as batteries,generators, or through a collector system.

• MATLAB modelof electric car which uses lithiumion battery and induction motor.Choose suitable blocks from Powertrain block set.

• To Modeland Simulate an electric vehicle with SIMULINK.

• Let us consider a modelinthisreport,an elect ric vehicle with a Induction motor and battery system using the SIMULINK .

• Inmodelling this EV fora drive cycle andtocheck periormance parameters :to measure speed,soc, and the current characteristics of its battery system.

Objectives:-

1. System level configurations

2. Model parameters

3. Results

4. Conclusion

BLOCK DIAGRAM:-

SUBSYSTEMS:-

vehicle body:-

• This subsystem represents the two axle vehicle body in motion.
• It accounts with a body mass, aerodynamic drag, grade,externally defined mass and center of gravity of the vehicle

Input ports:-

• W represents the wind velocity in m/s
• beta - Grade angle in radians.

Output ports:-

• V represents the velocity in m/s
• NR - Normal force on Rear Axle (N)
• NF-vNormal force on front axle(N)

Vehicle Body Parameters:-

• vehicle body mass, centre of gravity distance values and aerodynamic drag variables are modified.
• Pitch dynamics are kept ON with other variable values as default values.

Tires:-

• It is used to model a tire with longitudinal behavior given by equation on four fitting coeffiicients.
• The block can model tire dynamics under constant or variable contact surface conditions.

Input ports:-

• N denotes the Normal force acting on tire , positive when force is acting downwards/towards the contact surface.

Output ports:-

• here S is the output port where s denotes the slip value to tire and surface of contact.

Conserving ports:-

• here H- means hub which transmits the thrust generated by the wheel to the body of the vehicle.
• A- represents axle on which the tires are mounted.

Gear:-

• A simple gear block is used to connect the motor to the rear axle of the vehicles.
• It represents the gearbox which connects the input shaft to the base gear and output from the foller gear.

Conserving ports:-

• Here B represents the port associated with input shaft (motor shaft)
• and F denotes the port associated with output shaft (axle/ differential )

Simple Gear Parameters:-

• Gear ratio is modified and as well as output direction also modified.
• Meshing loss is kept constant, gear is having a constant efficiency throughout the simulation.
• other losses and faults are kept constant.

Motor power Converter:-

• The motor & its control block is as shown ,

H-Bridge:-

• The H bridge helps in controlling the power that is input according to the requirement.
• The output provided are converted voltage as per the controlled parameters.

Dc Motor:-

• This is the Dc motor would give the rotational power to the wheels.
• The Dc motors terminals are connected as mentioned below:
• +ve is electrical signal to the motor positive terminal.

• -ve is motor negative terminal, R- Casing of motor connected to mechanical rotational reference block.
• C- rotor case connected to the mechanical rotational reference.
• The parameters for armature inductance is default varies changes in the no load speed @8000rpm, the rated speed @5000rpm.
• the rated load at 50kw, and the rated DC supply voltage =300V. and remaining are default values are setted.

Controlled PWM voltage:-

• The Controlled PWM Voltage Block helps in keeping the Modulated Pulses as per the required pulses. So that the operations happens smooth and higher variations are not observed.
• The Ports ore connected osfollows,
• ref+ = Reference Positive connected with the Acceleration Commands from the Driver Model
• ref- = Reference Negative connectedwith the Deceleration Commands from the Driver Model
• PWM = PWM connected directly to the H-Block
• REF = REF connected directly to the H-Block ,and other parameters are set as default.

Battery source:-

• The battery is connected as the power source to the model so that the power could be generated and the same power is transmitted to all the operating sources.
• +ve terminal of the operating sources.
• -ve terminal of the operating sources are connected viceversa.

The components of Battery block is depicted below:-

• For Battery the rated 300 volts is considered as nominal voltage.

SOC estimate block:-

• the internal resitance is as per 0.5 ohms and others set as default.

Longitudinal Driver Model:-

• The Driver Modelhasthe Input and Output Ports which are connected to the following,

• Velocity Reference - Drive Cycle

• Velocity Feedback - Distance Calculation

• Grade - Constant 0

• Info - Not Connected

• Acceleration Command - Controlled PWM Source

• Deceleration Command - Brake inH-Bridge to maintain the speed accordingto the Drive cycle.

  Drive cycle:-

• Starting with the Drive cycle,let consider a WOT Drive cycle for the operation of the Cycle in which the test duration on would be 60 seconds.

Model of electric car Using battery and a DC motor

Outputs (Results):-

• The model has been simulated and run the model we can clearly observe the following graph from the scope,

1.The velocity Feedback and the drive cycle source:-

• As we can see that the actual velocity of the vehicle differs from the reference drive cycle velocity.
• This is because the chooses battery capacity and motors are not able to propel the speed upto the required extent.

Distance covered:-

• It may note that since, the reference velocity of drive cycle never becomes negative, by the way the distance travelled is increasing. total distance as 3.8km.

2.Battery soc:-

• As we can observe that the battery at the end of simulation run is nearly at 77%.
• That means battery is not going to drained completely , the vehicle can move some more distance on same drive cycle.

CONCLUSION:-

• As we have plotted the simulink model and plotted the graph with the FTP75 drive cycle.
• The results have properly analysed and mentioned.