Final Project: Design of an Electric Vehicle
Design of Electric Vehicle
Aim-
A MATLAB model of an electric car which uses a battery and a DC motor. Choose suitable blocks from
the Powertrain block set. Prepare a report about your model including the following.
Objectives-
1. System-level configurations
2. Model parameters
3. Results
4. Conclusion
Motor specification-
Armature inductance - 0.2 H
NO load rated speed - 9000 RPM
Full load rated speed - 8500 RPM
Rated mechanical power - 50 kW
DC supply voltage - 400 V
Tire specification-
Rolling radius - 0.3. m
Rated vertical load - 3000 N
Rated longitudinal force - 3000 N
Vehicle body specification-
Maas - 1200 kg
The number of wheels per axle - 2
gravitational acceleration - 9.81 kg/sec2
Screenshot of Matlab model-
https://photos.app.goo.gl/aQRfobHcYVce5sJf8
Screenshot of the subsystem of the model
https://photos.app.goo.gl/qRqMH9HXbULxLKrT6
https://photos.app.goo.gl/VRddYiuHBALhQawc6
https://photos.app.goo.gl/zWUPMTAgMbd9Q29W6
Theory-
Motor and controller are the main part of any electric vehicle. In the electrical vehicle, we
need the rotation of the vehicle in both the direction so we need to reverse the current for
that we need a converter and also we can use regenerative braking by returning the power
back to the source. While the motor is acting as a generator and feeding back to the source
and rotational energy(mechanical energy) is converted into electric energy so here vehicle
will start getting slow.
The power given to the dc motor is controlled by a converter(h-bridge).
Braking-
1 Electric braking- When we need to apply the brake then we will use the motor which
converts into the generator and which will convert rotational energy into
electric energy and vehicle will get slow.
2 Mechanical brake- Here we will use two plates one is rotating and one is stationary when
we need to apply the brake then we will attach them both so the vehicle starts getting slow
Battery-
It is the main source of energy for any electric vehicle so the quality of the battery is
important so that it can discharge slowly also Its life should be reasonable.
Matlab model Used blocks-
H-bridge(inbuild battery),DC motor,electrical reference,controlled PWM voltage, Voltage
controller, Drive cycle, Longitudinal driver, Constant, solver configuration, current sensor,
Double shoe brake, Tire, ps terminator, Simulink to ps converter, PS to Simulink converter
Simple gear, Integrator and scope
Procedure-
mechanical system-
1 I have connected the soft of the motor to the tire through gear.
2 Double shoe brake is connected with the rotatory part which is mechanical braking.
3 I have taken 4 wheels, two for front and two for back and rear wheel is connected.
4 Rear wheels only connected with soft.
4 Vehicle body is connected with tire by connecting NR to (N) rear wheels and FR front wheels (N), H to H (H is the mechanical connection of the vehicle body with tire for horizontal motion), Theta is the inclination angle of the vehicle, W is the air drag, V is the velocity of the vehicle.
Electrical system -
1 I have used a DC motor which is connected with an H-bridge which is having inbuild battery source that is controlled by a PWM voltage controller connected with the PWM of the H-bridge (giving the signal to turn on or turn off the h-bridge thyristor).
2 PWM voltage controller is connected with a controlled voltage source.
3 Controlled voltage source is connected with longitudinal drive (which helps to attain the particular drive cycle).
4 Longitudinal drive is also connected with H-bridge (brake node) through a controlled voltage source which helps to
convert motor into generator and vehicle start getting slow by losing rotational energy.
5 I have used FTP75 drive cycle and connected with longitudinal driver and longitudinal drive is feedback by the vehicle
velocity so that it should follow the required drive cycle.
6. Brake terminal is used to slow down the speed of the motor by converting it into a generator (by changing the direction of the current).
I have connected a scope with the output speed of the vehicle with the input drive cycle in which we can compare the speed required vs the speed of the vehicle.
I have given runtime as 2474 sec and run the model.
Output-
the graph between output speed vs required drive cycle screenshot-
https://photos.app.goo.gl/BsJghrir3ZTy9ZGVA
Distance vs time graph screenshot-
https://photos.app.goo.gl/CLLs6cEgNrAJpb6u6
As we can see the speed of the vehicle is not exactly following the drive cycle somewhat deviation is there
Here I have used a partial integral controller if I need more precision then I need to use a PID controller
and also as we will increase incline angle and air drag then we need to increase the capacity of the
motor as well. So the weight of the vehicle also affects the capacity of the motor.
conclusion-
As the weight of the vehicle increases then we are required to increase the capacity of the motor as well as
we are required to increase the battery capacity otherwise we will get undesired results.
And for more precision, we need a better controller and feedback signal.