Final Project: Electric Rickshaw modelling
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
Theory:
• Electric E-Rickshaw is also known as an electric tuk-tuk, e-rickshaw and auto which are going more popular after 2018 in the Indian market. This E-rickshaw is the best alternative to petrol/CNG auto-rickshaw and human or horse-pulled rickshaws because of their low fuel cost, zero emissions and less human efforts.
• The electrical system used in the Indian version is 48VDC can run 90-100 km/full charge, top speed 25 km/hour and this electric motor power ranging from 650-1400 Watts: the battery takes 8-10 hrs to become fully charged. Basic seating capacity is driver plus 4 passengers total of 5 persons.
The main objective of this project is to obtain speed by the driver, to estimate the temperature of the motor and controller, to estimate the state of charge (SOC) and distance travel by the vehicle. There is a SOC block that will estimate the state of charge of the battery, distance is calculated by speed and time parameter for all the three Drive cycle
vehicles details
# Battery Type Lithium-ion 330 V 75
# Vehicle kerb weight 260 kgs
# Load capacity 340 kgs
# Vehicle speed 7 kmph
# Driving range 140 km (160 Ah)
# No of wheels per axel 2
# Frontal Area 91m
# Drag coefficient 5 Wheel radius 306m
# Vertical load 3000 N
# Nominal Voltage 330 V
# Rated capacity 75Ah
# Initial SOC 100 %
# Internal Resistance 5 ohm
Blocks details used in simulation model of Electric rickshaw:
Controller and motor
DC motor:
This block represents the electrical and torque characteristics of a DC motor includes Thermal port to series the temperature of 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
• Motor parameters can either be specified directly or derived from the 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.
Controlled PWM:
This block creates a Pulse-Width Modulated (PWM) voltage across the PWM and REF ports. The output voltage is zero when the pulse is low and is equal to the Output voltage amplitude parameter when high.
The duty cycle is set by the input value. Right-click the block and select Simscape Block choices to switch between electrical ref/-ref ports and PS input u to specify the input value.
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. In PWM mode, the motor is powered if the PWM port voltage is above the Enable threshold voltage
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 HBridge 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
Temperature sensor:
• Temperature Sensor is used to measure the temperature of the H-Bridge and Motor.
This block measures temperature in a thermal network. There is no heat flow through the sensor. The physical signal port T reports the temperature difference across the sensor.
The measurement is positive when the temperature at port A is greater than the temperature at port B.
Vehicle body:
• Motor will produce the rotational output which will give to the vehicle body and transmission system. The rotational output is taken by the gear system here to maintain the constant speed throughout the transmission without any loss in speed from the motor to tires.
• Below is a diagram that is how it is inside the vehicle body and transmission system and in the main design, it is referred just only as a transmission system. Here I created a Rear-wheel drive transmission system.
• The gear output is given to axels of Rear tires in the circuit it is shown that gear is connected to Rear wheels and the front tire is free to rotational motion, thus the vehicle moves forward. N is the normal force caused by the tires and it is given to the vehicle body normal force port.
• The vehicle body has an H-Hub, S- Tire slip, N-Normal force. As axel connection, wind velocity, inclination angle. The tires hub is connected as a common node to the vehicle body.
• The vehicle body wind velocity is connected to a constant block and the beta-inclination angle is connected to another constant block where we can assign wind velocity and inclination angle as per requirement. Velocity is the output port where we can get at which speed the vehicle is moving. The velocity is taken out to get the distance travelled and state of charge
Tire (magic formula):
Battery:
whole system model:
