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

System level configurations

• Block Diagram
  • 
  • It is the diagrammatic representation of the Electric powertrain.
• Model
  • 
  • This model represents the Electric drive train of an Electric Vechicle.

Model parameters

• Drive Cycle
  • 
  • The Drive cycle block consists of n number of drive cycle .
  • The FTP75 Cycle is choosen for our simulation.
  • We acn also use our own drive cycle which can be imported in ".mat, .xls, .xlsx or .txt " file format.
  • It is the reference vehicle speed for our simulation.
  • The output velocity is mentioned in m/sec .
  • The Drive cycle run time is 2474 seconds.
  • Fault tracking
    
    • It is disabled for our simulation.
    • We can detect the error values (i.e The feedback is added to the block) .
    • We can also stop the simulation when the error value exists our range.
• Driver Block
  • It is the subblock which consists of Longitudinal driver block
  • 
  • It has 3 input variables
    • Velref -----> It is drive cycle signal.
    • Velref -----> The actual velocity of the vechicle is given as feedback signal.
    • Grade -----> The grade ability of the vechicle is given by the help of the constant block.
  • It has three Output
    • AccelCmd -----> It is acceleration signal .
    • DecelCmd -----> It is the deacceleration signal .
  • It is the PI controller block where the input velocity is compared with the output velocity.
  • It acts like a driver whose controlling the vechicle .
  • The PI controller tries to achieve the input velocity (refference velocity).
  • 
• Controller Block
  • It is the Subblock which consists of power converters .
  • 
    
    • Simulink-PS Converter
    • Controlled PWM Voltage.
    • H Bridge.
    • Voltage Controlled Source
    • Solver Configuration.
  • Voltage Controlled source
    • The block represents an ideal voltage source that is powerful enough to maintain the specified voltage at its output regardless of the current passing through it.
    • The output voltage is V = Vs, where Vs is the numerical value presented at the physical signal port.
  • Controlled PWM Voltage
    • This block creates the Pulse Width Modulated (PWM) Voltage .
    • The input ports are ref+ and ref-.
    • The output ports are PWM and Ref.
    • By the help of this block we can set the duty cycle .
    • For our simulation PWM switch frequency is 1000 Hz and the average mode is used.
    • 
    • From the Input scaling tab,We can set the input voltage .
    • For our simulation the minimum input voltage is 0 V and the maximum input voltage is 5 V.
    • 
    • From the output voltage tab,We can the set output voltage .
    • For our simulation the minimum output voltage is 0 V and the maximum output voltage is 7 V.
    • The duty cycle is setted in the ratio of boost manner.
    • 
  • H-Bridge
    • This block represents an H-bridge motor drive.
    • The block can be driven by the Controlled PWM Voltage block in PWM or Averaged mode.
    • By the help of H bridge the motor can be run in both forward and reverse motoring operation.
    • The H bridge will control both battery and the motor.
    • It consists of 4 inputs .
      • PWM -----> The output of the Controlled PWM voltage block is connected to it.
      • Ref -------> It is the refference port which is also connected from the Controlled PWM voltage block.
      • Rev -------> The poet stands for reverse motor operation.
      • Brk --------> The port stands for Braking of motor opertion.
      • For the Rev port is connected from the acceleration command from the driver block.
      • For the Brk port is connected from the Deacceleration command from the driver block.
    • It consists of two outputs.
      • + ve ----> is connected for the battery controll.
      • - ve is connected for the motor controll.
    • Simulation and load Assumption
      • 
    • Input Thresholds
      
      • 
    • Bridge Parameters
      • To run the motor 330 V is setted as output voltage.
      • The remaining parameters are setteda s default values.
      • 
  • Solver Configuration
    • Each physical network represented by a connected Simscape block diagram requires solver settings information for simulation.
  • Simulink-PS Converter
    • Converts the Simulink input signal to a Physical Signal.
    • Here the two blocks are used.
    • The Simulink input signal is Acceleration command and deacceleration command.
    • The Physical signal is controlled voltage source.
  • Electrical Rerference
    • The Electrical Reference block represents an electrical ground.
    • Electrical conserving ports of all the blocks that are directly connected to ground must be connected to an Electrical Reference block.
    • A model with electrical elements must contain at least one Electrical Reference block.
• Battery
  • It is the Subblock which consists of
    • Battery.
    • Soc unit.
    • PS Simulink block.
    • Controlled Current Source.
    • Current sensor.
  • 
  • Battery
    • 
    • For our simulation we have used 400 v battery.
    • The dynamics and variables are set as default values.
  • Controlled Current Source
    • It is connected to the Battery.
    • The Controlled Current Source block represents an ideal current source that is powerful enough to maintain the specified current through it regardless of the voltage across the source.
    • The output current is I = Is, where Is is the numerical value presented at the physical signal port.
  • Current Sensor
    • It has 3 ports
      
      • + ve ----->It is connected to the +ve of the H bridge.
      • - ve -----> it is connected to the +ve of the motor.
      • I ----------> It is connected to the Controlled current source.
  • PS-Simulink Converter
    • Converts the input Physical Signal to a Simulink output signal.
    • The Physical siganl is output of the current siganl.
    • The Simulink signal is connected to the scope.
  • SOC
    • 
    • PS-Simulink Converter
      • Converts the input Physical Signal to a Simulink output signal.
      • The Physical siganl is output of the current sensor I.
      • The Simulink signal is connected to the Rate Transition.
    • Rate Transition
      • The Rate Transition block transfers data from the output of a block operating at one rate to the input of a block operating at a different rate.
      • The values are setted as default.
    • Gain
      • 
      • By multiplying with (1/80*3600) we can find the nominal battery capacity of the battery
    • Discrete Time Integrator
      • Use the Discrete-Time Integrator block in place of the Integrator block to create a purely discrete model.
      • It is used to convert the dicrete to integrated signals.
      • The values are setted as default values.
    • Constant
      • Here the 100 represents the battery intial charge percentage.
    • Summer
      • To find the current battery percentage The inital SOC and Discrete Time integrator are subracted .
• DC Motor
  • 
  • For our simulation the DC Permanent magnet motor is used.
  • It has two inpiut and two outports
    • The input ports are Electrical (+Ve & - Ve)
      • The + ve is connected from the - ve of the current sensor.
      • The - ve is connected from the - ve of the voltage sensor.
    • The output ports arer Mechanical (C & R)
      • C is connected to the Mechanical rotational refference.
      • R is conected to the simple gear block in Vechicle body sub block.
    • Mechanical and Faults are setted as default values.
• Vehicle Body
  • 
  • It is the sub block which consists of
    
    • Simple Gear
    • Tire (Magic Formulae) 4
    • Interia
    • Vechicle Body
    • PS-Simulink Converter
    • Gain
    • Zero Order Hold
  • Simple Gear
    • 
    • It has two ports
      • B port
        • It is connected from the R port of the DC motor.
      • F port
        • It is connected to the A port of the Tire
    • The gear ratio is setted as 3.75 for the optimistic value for our simulation.
    • The meshing losses is setted as 0.89 efficiency.
    • The viscous and faults tab are setted as default values.
  • Inertia
    • The block represents an ideal mechanical rotational inertia.
    • 
    • The values are setted as default.
    • It is connected between Simple gear and tire
  • Tire
    • For our simulation we have selected the Tire (magic formulae).
    • 
    • Represents the longitudinal behavior of a highway tire characterized by the tire Magic Formula.
    • The block is built from Tire-Road Interaction (Magic Formula) and Simscape Foundation Library Wheel and Axle blocks.
    • Optionally, the effects of tire inertia, stiffness, and damping can be included.
    • It has four ports
      • N (Normal Force) Port
        • Physical signal input port associated with the normal force acting on the tire.
        • The normal force is positive if it acts downward on the tire, pressing it against the pavement
      • H (Hub) Port
        • Mechanical translational port associated with the wheel hub that transmits the thrust generated by the tire to the remainder of the vehicle.
      • A (Axle) Port
        • Mechanical rotational port associated with the axle that the tire sits on.
      • S (Slip) Port
        • Physical signal output port associated with the relative slip between the tire and road.
    • The 4 tyres are used
      • 2 tyres are connected to the rear axle.
      • 2 tyre are connected to the front axle.
    • The geometry, dynamics , advanced are setteds as default values.
    • Rolling resistance is enabled.
  • Vehicle Body
    • Represents a two-axle vehicle body in longitudinal motion.
    • The block accounts for body mass, aerodynamic drag, road incline, and weight distribution between axles due to acceleration and road profile.
    • 
  • PS-Simulink Converter
    • Converts the input Physical Signal to a Simulink output signal.
    • The Physical siganl is output of the V (velocity experienced by the vechicle).
    • The Simulink signal is connected to the Gain.
  • Gain
    
    • The m/sec is converted to Km/hr by multiplying the 3.6 with it.
  • Zero Hold order
    • The Zero-Order Hold block holds its input for the sample period you specify.
    • If the input is a vector, the block holds all elements of the vector for the same sample period.
    • A setting of -1 means the block inherits the Sample time.
• Distance Travelled
  • 
  • It is the subblock which is used for calculating the distance travelled by the vechicle.
  • By integrating the Velocity of the vechicle and multiplying with 3600 we can find the ditance traveled by the vehicle in Km.
• Result
  • 
  • Reffernce speed Vs Vechice body
    • From the plot we can find there is the difference between the refference speed and the vechicle speed.
    • The refference speed is the duty cycle which runs for 2474 seconds
    • The PI controller tries to achieve the same speed as reference speed.
    • By varrying the gear ratio and the duty cycle we can achieve the vehicle speed close to refferernce speed.
    • During the downfall of the speed we can notice the regenerative braking is applied so the vechicle takes some time to reaches the minimum speed.
  • Current (A)
    • It is the current entering through the armature winding.
    • When the speed is maximum we can see that the motor utilizing the maximum current (positive flow of current)of 250 A.
    • When the regerative braking is applied we can see the motor acts as an generator and supplies the current to the battery (negative flow of current).
    • We regerative current is not same as maximum current due to the battery and powert converters limitations.
  • Battery (%)
    • For the total run time of 2474 seconds the battery state os discharge is 61%.
    • We camn also see that the battery gets charged when the motor operates in regerative mode.
  • Distance
    • 
    • The total distance travelled by the vechicle is 5.141 Km in 2474 seconds.
• Conclusion
  • The EV model is attached as "Project".
  • The simulation is done by the matlab software.
  • The Drive cycle used is FTP75 which has the runtime of 2474 seconds.
  • The working of the model is explined in detailed.
  • From the simulation we can understand the basic working of the EV model with the losses associated with it.