Final Project: Design of an Electric Vehicle
Aim
Create a MATLAB model of electric car which uses a battery and a DC motor. Choose suitable blocks from Powertrain
blockset.
Objectives:
1. System level configurations
2. Model parameters
3. Results
4. Conclusion
Electric vehicle (EV) is defined as a vehicle that uses an electric motor or a traction motor for propulsion unlikely to an
internal combustion (IC) engine used by conventional vehicles. Electric vehicles use electric power instead of fuels as
conventional vehicles would and because of this difference, electric vehicles do not produce any exhaust gases or
pollution(Zero emission). The power needed for the operation of an EV can come from a variety of sources such as
batteries, generators, or through a collector system.
MATLAB model of electric car which uses lithium ion battery and induction motor. Choose suitable blocks from
Powertrain block set :
To Model and Simulate an electric vehicle with SIMULINK.
Let us consider a model in this report, an electric vehicle with a Induction motor and battery system using the
SIMULINK . In modelling this EV for a drive cycle and to check performance parameters : to measure speed, SOC , and the
current characteristics of its battery system etc.
Components
The main components of modelling an EV are :
Vehicle body
Motor & motor controllers
Power converters
Batteries
Drive cycle
Block Diagram
Model
Vehicle Body
The above Figure represents the Vehicle Body.
Input Ports:
W - Wind Velocity in m/s
beta - Grade angle in radians
Output Ports:
V - Velocity in m/s
NR - Normal force on Rear Axle (N)
NF - Normal Force on Front Axle (N)
Tires
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 Port
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.
Gear
Conserving Ports :
B - port associated with input shaft (motor shaft)
F - port associated with ouput shaft (axle / differential)
Simple Gear Parameters :
Gear ratio and output direction is modified.
Meshing loss is kept constant and gear is having a constant efficiency throughout the simulation.
Viscous losses and faluts are kept at default conditions.
Motor and Power Convertor :
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 which would give the rotational power to the wheels and become the sole power generation source.
The DC Motors terminals are connected as mentioned below,
+ = Electrical signal to the motor Positive Terminal
- = Electrical signal to the motor Negative Terminal
R = Casing of the Motor connected with the Mechanical Rotational Reference Block
C = Rotor Case connected to the Mechanical Rotational reference
The parameter considered are, The Armature inductance is as default, varied the changes in the No-Load Speed @ 8000
rpm, the rated speed @ 5000 rpm, the Rated Load at 50kW, and the Rated DC Supply Voltage @ 300 V. All other
parameters are as default.
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 are connected as follows,
ref+ = Reference Positive connected with the Acceleration Commands from the Driver Model
ref- = Reference Negative connected with the Deceleration Commands from the Driver Model
PWM = PWM connected directly to the H-Block
REF = REF connected directly to the H-Block
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 accordingly to all the operating sources.
The terminals connected are to,
+ = The positive terminal of the operating sources
- = The negative terminal of the operating sources.
Components of battery block is depicted below :
The paramters considered of the battery are -
The battery Nominal Voltage is rated as per 300 Volts,
The internal resistance is as per 0.5 Ohms and others set as default.
Driver Model :
The Driver Model has the 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 in H-Bridge to maintain the speed according to 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
would be 60 seconds.
Outputs :
1.The Velocity Feedback and the Drive Cycle Source :
2. Battery SOC :
