Final Project: Design of an Electric Vehicle

PROJECT-

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

SOLUTION = ELECTRICAL VEHICLE DESIGN

electrical vehicle

- The electric vehicle uses battery source and electric motor for its propulsion.

- Electric vehicles have high efficiency compared to ICE. Losses in EV are also less.

- The motors used for propulsion of EV can be any of the below:

1.Permanent magnet synchronous motor

2. Three phase induction motor

3. BLDC motor

4. Switched reluctance motor

BLOCK DIAGRAM OF EV:

simulink model:

block used:

1) drive cycle

drive cycle plot:

2) Longitudinal driver:

specification:

3) controlled voltage source: This block is used to maintain the specified voltage at its output regardless of the current flowinng through source.

4) controlled PWM voltage : Used to create pulse width modulated voltage.

5) H-bridge: Used to change the polarity of voltage applied across DC motor so as to run the motor in forward and reverse direction as per input command.

6) Current sensor block: Used to measure current flowing through H- bridge.

7) DC motor : To convert electrical energy to mechanical energy. In regenrative braking motor the mechanical energy gets converted into electrical energy.

8) vehicle body: The block represents a two axel vehicle body in longitudinal motion. The block accounts for body mass, aerodynamic drag, road incline weight distribution between axel due to acceleration, road profile.

9) tire:

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

Input Port:

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

Output Port:

• S - Slip value relative to tire and surface of contact.

Conserving Ports:

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

specification:

10) simple gear:

Conserving Ports:

• B - port associated with input shaft (motor shaft)
• F - port associated with ouput shaft (axle / differential)

specification:

11) battery

specification

output :

drive cycle & vehicle velocity:

- The vehicle velocity plot is following the drive cycle velocity curve, it means the controller trying to minimize the error in between them.

- There is some difference in drive cycle and vehicle velocity, this is beacause of inertia of vehicle mass.

longitudanal driver acceleration:

battery soc , current & voltage:

conclusion : The model was succesfully ran for simulation under the standard FTP75 drive cycle. The results have been properly analyzed.

Also, learnt quite a lot of interesting things like -

1. how to model an EV and carry out a real time simulation
2. how a motor controller works and what role it plays in the control of the electric motor
3. how to calculate the SOC of the battery
4. different powertrain blocks provided by simulink which can be used to simulate a vehicle model.