Electric Rickshaw Modelling

Question :-

Create a detailed MATLAB model of an electric rickshaw (three wheel passenger vehicle) as per details below:

Rear wheels driven by PM brushed type motor

Assume efficiency points of motor controller and motor

Make an excel sheet of all input and assumed data

Results: For any three standard driving cycles show energy consumption, temperature rise of motor and controller for 100 km constant speed driving at 45 kmph.

(Note- The simulink model file should be compulsorily attached)

Answer :-

• This is a simulink model of an electric rickshaw.

• Here main block/component are describe as below.
  
  • Drive Cycle
  • H-Bridge
  • Battery
  • DC Motor
  • Longitudinal Driver

• List of block which is use in electric rickshaw you can see below.

rickshaw

rickshaw/Battery

rickshaw/Constant

rickshaw/Constant1

rickshaw/Constant2

rickshaw/Controlled Current Source

rickshaw/Controlled PWM Voltage

rickshaw/Controlled Voltage Source

rickshaw/Controlled Voltage Source1

rickshaw/Current Sensor

rickshaw/DC Motor

rickshaw/Distance

rickshaw/Divide

rickshaw/Drive Cycle Source1

rickshaw/Drive Cycle Source2

rickshaw/Electrical Reference

rickshaw/Electrical Reference1

rickshaw/From Spreadsheet

rickshaw/H-Bridge

rickshaw/Integrator

rickshaw/Longitudinal Driver

rickshaw/Mechanical Rotational Reference

rickshaw/Multiport Switch

rickshaw/Output

rickshaw/PS-Simulink Converter1

rickshaw/PS-Simulink Converter2

rickshaw/PS-Simulink Converter3

rickshaw/Scope3

rickshaw/Signal Builder

rickshaw/Simulink-PS Converter

rickshaw/Simulink-PS Converter1

rickshaw/Solver Configuration

rickshaw/Temperature Sensor

rickshaw/Temperature Sensor1

rickshaw/Terminator

rickshaw/Thermal Reference

rickshaw/Thermal Reference1

rickshaw/Vehicle

rickshaw/Vehicle/PS Constant

rickshaw/Vehicle/PS Constant1

rickshaw/Vehicle/PS-Simulink Converter1

rickshaw/Vehicle/PS-Simulink Converter2

rickshaw/Vehicle/PS-Simulink Converter3

rickshaw/Vehicle/Rotational Free End

rickshaw/Vehicle/Scope

rickshaw/Vehicle/Simple Gear

rickshaw/Vehicle/Tire (Magic Formula)

rickshaw/Vehicle/Tire (Magic Formula)2

rickshaw/Vehicle/Tire (Magic Formula)3

rickshaw/Vehicle/Vehicle Body

rickshaw/Vehicle/V

rickshaw/Vehicle/Conn6

1.) Drive Cycle :-

• Input Drive Cycle Source
  • FTP75 drive Cycle
  • Signal Builder
  • Wide Open Throttle(WOT)
  • Excel Sheet

• FTP75 drive Cycle input
  • The FTP75 represents a city drive cycle.

• Signal Builder input ---> As per requirement we should drive 28820 sec. for 100km
  • Create and generate interchangeable groups of signals whose waveforms are piecewise linear.

• Wide Open Throttle(WOT)
  • Wide open throttle (WOT) parameters, including initial and nominal reference speed, deceleration start time, and final reference speed.

• This is an Excel Sheet which get from google.

2.) Battery :-

• Battery parameters :- Battery parameters are based on Nominal voltage, Internal resistance, Open-circuit measurement temperature and etc.
• Here I select Infinite for the Battery charge capacity parameter, the block models the battery as a series internal resistance and a constant voltage source.

• Battery charging (SOC) is dependent on these equation.
  • V = Vnom*SOC/(1-beta*(1-SOC))

• PWM (Pulse Width Modulater)
• Controlled PWM Voltage :- Pulse-width modulated voltage source
  • Averaged mode :- the output is constant with value equal to the averaged PWM signal.
  • Frequency of the PWM output signal is 1000Hz.
  • PS input — Specify the duty cycle value directly by using an input physical signal port.

• Value of the input voltage at which the PWM signal has a 0% duty cycle - 0V (default value)
• Value of the input voltage at which the PWM signal has a 100% duty cycle - 5V (default value)

• Amplitude of the PWM signal when the output is high - 5V (default value)

3.) H-Bridge

• H-Bridge parameters with thermal port :-
  • This block represents an H-bridge motor drive. The block can be driven by the Controlled PWM Voltage block in PWM or Averaged mode.In Averaged mode, the PWM port voltage divided by the PWM signal amplitude parameter defines the ratio of the on-time to the PWM period. Using this ratio and assumptions about the load, the block applies an average voltage to the load that achieves the correct average load current. The Simulation mode parameter value must be the same for the Controlled PWM Voltage and H-Bridge blocks.
  • If the REV port voltage is greater than the Reverse threshold voltage, then the output voltage polarity is reversed. If the BRK port voltage is greater than the Braking threshold voltage, then the output terminals are short circuited via one bridge arm in series with the parallel combination of a second bridge arm and a freewheeling diode. Voltages at ports PWM, REV and BRK are defined relative to the REF port.
  • If exposing the power supply connections, the block only supports PWM mode
  • PWM - The H-Bridge block output is a controlled voltage that depends on the input signal at the PWM port. If the input signal has a value greater than the Enable threshold voltage parameter value, the H-Bridge block output is on and has a value equal to the value of the Output voltage amplitude parameter. If it has a value less than the Enable threshold voltage parameter value, the block maintains the load circuit using one of the following three Freewheeling mode options:
    
    • Via one semiconductor switch and one freewheeling diode
    • Via two freewheeling diodes
    • Via two semiconductor switches and one freewheeling diode
  • The first and third options are sometimes referred to as synchronous operation.
  • The signal at the REV port determines the polarity of the output. If the value of the signal at the REV port is less than the value of the Reverse threshold voltage parameter, the output has positive polarity; otherwise, it has negative polarity.
  • Average - This mode has two Load current characteristics options:
    • Smooth
      • The smoothed option assumes that the current is practically continuous due to load inductance.
    • Unsmooth / discontinuous

• Input Thresholds :-
  • Enable threshold voltage :- Threshold above which the voltage at the PWM port must rise to enable the H-Bridge block output.
  • PWM signal amplitude :- The amplitude of the signal at the PWM input
  • Reverse threshold voltage :- When the voltage at the REV port is greater than this threshold, the output polarity becomes negative.
  • Braking threshold voltage :- When the voltage at the BRK port is greater than this threshold, the H-Bridge block output terminals are short-circuited via the following series of devices:
    • One bridge arm
    • One bridge arm in parallel with a conducting freewheeling diode

• Bridge parameters :-
  • Output voltage amplitude: The amplitude of the voltage across the H-Bridge block output ports when the output is on.
  • Total bridge on resistance: The total effective resistance of the two semiconductor switches that connect the load to the two power rails when the voltage at the PWM port is greater than the value of the Enable threshold voltage parameter on the Input Thresholds tab.
  • Freewheeling diode on resistance: The total resistance in the freewheeling diodes that dissipate the current that flows through the motor when the voltage at the PWM port is less than the value of the Enable threshold voltage parameter on the Input Thresholds tab.
  • Measurement temperature: The temperature for which the resistance values on the Bridge Parameters tab are specified.

• Temperature Dependence :-
  • Total bridge on resistance at second measurement temperature: The total effective resistance of the two semiconductor switches that connect the load to the two power rails (as described in the Total bridge on resistance parameter definition), quoted at the Second measurement temperature.
  • Freewheeling diode on resistance at second measurement temperature: The total resistance in the freewheeling diodes that dissipate the current that flows through the motor (as described in the Total bridge on resistance parameter definition), quoted at the Second measurement temperature.
  • Second measurement temperature: The temperature for which for which the resistance values on the Temperature Dependence tab are specified.

• Thermal Port :-
  • Thermal mass : Thermal mass associated with the thermal port H. It represents the energy required to raise the temperature of the thermal port by one degree.
  • Initial temperature:The temperature of the thermal port at the start of simulation.

4.) DC Motor :-

• DC Motor parameters with thermal port :-
  • DC motor model with electrical and torque characteristics and fault modeling
  • This block representing an electrical parameters of DC Motor like field type, model parameters, speed ,voltege, armature inductance and so on.
  • This block represents the electrical and torque characteristics of a DC motor.
  • The block assumes that no electromagnetic energy is lost, and hence the back-emf and torque constants have the same numerical value when in SI units. Motor parameters can either be specified directly, or derived from no-load speed and stall torque. If no information is available on armature inductance, this parameter can be set to some small non-zero value.
  • When a positive current flows from the electrical + to - ports, a positive torque acts from the mechanical C to R ports. Motor torque direction can be changed by altering the sign of the back-emf or torque constants.

• This block representing a mecanical construction of DC Motor.

• Resistance temperature coefficient.
• The temperature for which motor parameters are defined.

• The thermal mass is the energy required to raise the temperature by one degree.
• The temperature of the thermal port at the start of simulation.

5.) Longitudinal Driver

• Longitudinal Driver :- Longitudinal speed - tracking controller
  • Here, I am use PI controller (Proportional-integral control with tracking windup and feed-forward gains.)
  • 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.
  • A parametric longitudinal speed tracking controller for generating normalized acceleration and braking commands based on reference and feedback velocities.
  • Use the external actions to input signals that can disable, hold, or override the closed-loop commands determined by the block. The block uses this priority for the input commands: disable, hold, override.

• This is the inside part of vehicle like
  • Vehicle body
  • Tire
  • Slimple gear (like :- Differential)

• 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. The vehicle can have the same or a different number of wheels on each axle. Optionally include pitch and suspension dynamics or additional variable mass and inertia. The vehicle does not move vertically relative to the ground.
  • Connection H is the mechanical translational conserving port associated with the horizontal motion of the vehicle body. The resulting traction motion developed by tires should be connected to this port. Connections V, NF, and NR are physical signal output ports for vehicle velocity and front and rear normal wheel forces, respectively. Wheel forces are considered positive if acting downwards. Connections W and beta are physical signal input ports corresponding to headwind speed and road inclination angle, respectively. If variable mass is modeled, the physical signal input ports CG and M are exposed. CG accepts a two- element vector representing the x and y distance offsets from vehicle CG to additional load mass CG. M represents the additional mass. If both variable mass and pitch dynamics are included, the physical signal port J accepts the inertia of the additional mass about its own CG.

• In vehicle aerodynamics vehicle drag is main parameter now a day.
• Vehicle drag is depends on these three major parameters :-
  • Frontal area
  • Drag coefficient
  • Air density

• Simple Gear :- Which gives power to rear wheels.
• Here, we consider gear ratio is 5.

• Tire (Magic Formula) :- In this model we have three wheels in which two are driver and another one is driven.
• This is the tire parameters :- Which gives information about tire geometry, applied load and force and other related informations.

• Here, I take rolling radius is 0.3m.

• Here, I take velocity threshold is 0.1m/s.

• Result
  • Drive cycle : Output
  • This is final output scope which indicates input drive cycle(yellow) and output drive cycle(blue).
  • This scope also give difference between both drive cycle.
  • here, both cycle more than 95% similar with each other.

• • DC Motor & H-Bridge : Thermal Output
  • This is thermal output scope of DC Motor & H-Bridge which indicates how much temperature increase during operation.
  • Yellow one is give information about DC Motor temperature and blue is give information about H-Bridge temperature.
  • Motor temperature is gradually increase with time while H-Bridge temperature is constant.

• • Tire - scope
  • It is An electric rickshaw (three wheel passenger vehicle) so here rear wheels are driver wheels and front wheel is driven wheel.
  • Front wheel has push by rear wheel and its run so no power consumed over there and rear axle is driven by motor power and then it goes on rear wheel.