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
ANS
ELECTRIC CARS:
An Electric car is powered by an Electric Motor rather than a Gasoline Engine.
The Electric Motor gets its power from a controller.
The Controller is powered from an array of rechargeable batteries.
we are Creating a MATLAB model of electric car which uses a battery and a DC motor.
as shown in above block diagram we will make matlab simulink model of electric car first we give drive cycle than a driver we will make two subsystem lastly we will see inputdrive cycle and output velocity of vehicle there should not be much difference in them ans by running this drive cycle we will see state of charge of battery it must drain now we will see the simulink model and discuss each part of it
MATLAB model of electric car which uses a battery and a DC motor
Longitudinal Driver1
The Longitudinal Driver block implements a longitudinal speed-tracking controller. Based on reference and feedback velocities, the block generates normalized acceleration and braking commands that can vary from 0 through 1. You can use the block to model the dynamic response of a driver or to generate the commands necessary to track a longitudinal drive cycle.
Subsystem:
Controlled PWM Voltage block:
The Controlled PWM Voltage block represents a pulse-width modulated (PWM) voltage source.
This block produces PWM signal given as input to the H-bridge.
A controlled voltage source block is used to produce voltage equal to the acceleration command between 0 & 1. This voltage is given as input to the controlled PWM voltage
block.
Under block parameters, simulation mode is set as 'Averaged for fast simulation. Input voltage for 0% duty cycle & 100% duty cycle is set
as 0 & 1, respectively. All other parameters are kept as default.
H-Bridge
The H-Bridge block represents an H-bridge motor driver.
Pwm- The H-Bridge block output is a controlled voltage that depends on the input signal at the PWM port It controls the power input to the motor according to the load requirements by controlling the input voltage to the motor. H-bridge is configured to have its power supply internal.
Simulation mode is configured as 'Averaged to achieve fast simulation. Regenerative braking is also enabled. Output voltage amplitude is set as equal to the rated voltage of the motor, Le.. 300V. All other parameters are kept as default. For braking command, a controlled voltage source block is used to produce voltage equal to the deceleration command from the driver.
DC motor:
https://www.mathworks.com/help/physmod/sps/ug/example-modeling-a-dc-motor.html
This block represents the electrical and torque characteristics of a DC motor. Port connections are made as shown in subsystem 1 Under
block parameters electrical torque tab.
model parameterization is changed to 'By rated load & speed
No-load speed, rated speed, rated load. & rated DC supply voltage is configured with values 8000 rpm, 3100 rpm, 75kW, & 300V respectively, and all other parameters are kept as default.
The rated power of the motor is calculated by considering the forces acting on the vehicle, Le., rolling resistance, aerodynamic drag at top speed and the acceleration power required by the vehicle.
SOC
This subsystern takes current as input and gives the battery SOC % as output. A controlled current source block is used and connected with the battery.
This block drains the battery with the same current drawn by the motor and also recharges during regenerative braking.
This block estimates the battery SOC % using coulomb counting method. It takes current as the input and gives SOC % as output. Initial SOC of the battery is assumed to be
100%. And while calculating the SOC, battery capacity is assumed to be 100 Ah.
BATTERY
Nominal voltage & internal resistance is set to 300V & 0.3 ohms, respectively. All other parameters are kept default.
Solver configuration
f(x) = 0
Solver configuration - it provides solver setting information to model.
CURRENT SENSOR
Ammeter - it measures current and it is connected With motor and h bride in series. It is used to indicate state of charge.
Controlled Voltage Source:
Subsystem2:
Vehicle Body
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. For example, two wheels on the front axle and one wheel on the rear 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.
The block has an option to include an externally-defined mass and an externally-defined inertia. The mass, inertia, and center of gravity of the vehicle body can vary over the course of simulation in response to system changes.
the values applied to the block as shown in below
Tire (Magic Formula)
the tire specifcations are shown as below we choose
Simple Gear
it represents a gear box that constrains the connected driveline axes of the base gear and follower gear, corotate With specified gear ratio.
We use 2 as gear ratio.
Distance travel by vehicle:
Vehicle velocity compaired with the input driving cycle
Result:
conclusion:
we run the electric car model in simulink environment the output velocity of vehicle and and given drive cycle input match so we can say vehicle is running as per our required drive cycle the ans as the vehicle run the battery drains the soc also reduces, the distance travel is 6.124 km