Final Project: Electric Rickshaw modelling

AIM: To create a detailed MATLA model of an Electric Rickshaw (Three wheel passenger vehicle).

Abstract:

• In this project, we are going to build the MATLAB model of the ELECTRIC RICKSHAW by using a PM brushed type DC motor and a suitable Lithium-lon battery for the motor.
• In this project we also understand the basics information of Electric Rickshaw. In this model we will take three different drive cycle and give the constant speed of 45kmph for 100 km .

Objectives:

• 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.

Methodology:

• The Electric Rickshaw is consists of a battery, motors, gear system and controller then it generates propulsion power.
• To design any vehicle first we have to calculate propulsion power then the motor is selected.
• Operating range, motor rating everything is depend upon the battery capacity that we have selected.

So, the Design flow of the vehicle engineers has to be like the following

AIM: To create a detailed MATLA model of an Electric Rickshaw (Three wheel passenger vehicle).

Abstract:

• In this project, we are going to build the MATLAB model of the ELECTRIC RICKSHAW by using a PM brushed type DC motor and a suitable Lithium-lon battery for the motor.
• In this project we also understand the basics information of Electric Rickshaw. In this model we will take three different drive cycle and give the constant speed of 45kmph for 100 km .

Objectives:

• 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.

Methodology:

• The Electric Rickshaw is consists of a battery, motors, gear system and controller then it generates propulsion power.
• To design any vehicle first we have to calculate propulsion power then the motor is selected.
• Operating range, motor rating everything is depend upon the battery capacity that we have selected.

So, the Design flow of the vehicle engineers has to be like the following:

Introduction:

• Electric E-Rickshaw is also known as electric tuk-tuk, e-rickshaw and auto which are going more popular after 2018 in Indian market.
• This E-rickshaw is best alternative of 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 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 passenger total 5 persons.
• Here basically, e-rickshaw is designed in CREO and MATLAB Simulink.
• In the designed electric rickshaw main blocks are Battery, Drive Cycle, Controller, Dc Motor, Vehicle Body and Transmission System. Drive cycle is the input of human effort that how he is going to drive his actual cycle. We can use drive cycle like FTP75, WOT and by signal builder.

Construction:

• No doubt that battery operated vehicle is robust and strong enough. Also, it is ensured that this vehicle provides all the facility for the comfort of every passenger.
• No doubt there are a hell lot of E-Rickshaw spare parts required for the construction of e-rickshaw.
• Also, the vehicle is crafted with the best quality of metal and fiber glass. Among the other materials, an open frame is used for the construction of these e-rickshaws.
• The rickshaw is no doubt cost-effective because it is battery operated as well as consumes less energy.
• The 3-wheeler E- rickshaw is definitely the best substitute for fuel driven vehicles and efficient when comes to battery power. Also, there is no emission of harmful pollutants from this vehicle so it helps to increase the durability and strengthens the vehicle.
• The materials which are used in constructing the vehicle such as fibreglass help it to make the vehicle more efficient. Also, this vehicle is absolutely perfect to cover the short distance as well as carry small loads.

Specifications of the Electric Rickshaw:

Mass of the vehicle – 600 kg

Vehicle Speed – 7 kmph

Nominal Voltage – 60 v

Rated Capacity – 630 Ah

PWM frequency – 1000 hz

Vertical load – 3000 N

Wheel Radius – 306mm

Frontal area – 1.48 m^2

Drag co-efficient – 0.5

Air density – 1.18 kg/m^3

Rolling resistance – 0.3

Initial SOC – 100%

Simulink Model:

Procedure:

Vehicle Dynamics Subsystem:

• The 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 includes vehicle body, two rear and one front wheel, simple gear.
• The gear output is given to axels of Rear tires, in the circuit it is shown that gear is connected to Rear wheels and front tire is free to rotational motion, thus 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, A-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 the get the distance travelled and state of charge.

Tire:

• Represents the longitudinal behaviour 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.
• Connection A is the mechanical rotational conserving port for the wheel axle. Connection H is the mechanical translational conserving port for the wheel hub through which the thrust developed by the tire is applied to the vehicle. Connection N is a physical signal input port that applies the normal force acting on the tire. The force is considered positive if it acts downwards.
• Connection S is a physical signal output port that reports the tire slip. Optionally expose physical signal port M by setting Parameterize by to Physical signal Magic Formula coefficients. Physical signal port M accepts a four element vector corresponding to the B, C, D, and E Magic Formula coefficients.

Vehicle Body:

• This block basically represents a two-axle vehicle body in longitudinal motion. The block accounts for - body mass, aerodynamic drag, road incline, weight distribution between axles due to acceleration road profile.
• Here, the connection H is the mechanical translational conserving port hub. NF & NR correspond to the output parts for normal reaction forces on front axle and rear axle wheels respectively.
• Connection V represents the actual output translational velocity of the vehicle. beta is the road inclination angle & W corresponds to the headwind speed (headwind - direction opposite to that of vehicle). The gross weight is given to be 600 kg.

Motor and Gear Subsystem:

Gear:

• Represents a fixed-ratio gear or gear box. No inertia or compliance is modelled in this block. You can optionally include gear meshing and viscous bearing losses. Keeping the gear box has a gear ratio of 5 for this model
• Connections B (base) and F (follower) are mechanical rotational conserving ports. Specify the relation between base and follower rotation directions with the Output shaft rotates parameter.
• Optionally include thermal effects and expose thermal conserving port H by right-clicking on the block and selecting Simscape block choices to switch between variants. From this block the gear related variables are changed.
• The output of the gear is given to the wheels. The normal force of the vehicle is also given to the tires as input.
• Tire slip is not considered in the simulation. Tyre generates the force to move the vehicle. This force is given to the vehicle body block. Vehicle speed is the ultimate output of this system.

Dc Motor:

• This block represents the electrical and torque characteristics of a DC motor includes the thermal port to sense 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 Sl 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 flow 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.

Temperature Sensor:

• This block is used to measure the temperature of 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.

Power Controller Subsystem:

Controlled PWM Voltage:

• 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.
• At time zero, the pulse is initialized as high unless the duty cycle is set to zero or the Pulse delay time is greater than zero.
• The Simulation mode can be set to PWM or Averaged. In PWM mode, the output is a PWM signal. In Averaged mode, the output is constant with value equal to the averaged PWM signal. Select Simulation mode as Averaged.

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.

Solver Configuration:

Defines solver setting to use for simulation.

Battery and SOC Subsystem model:

Battery:

• The battery is required to power the controller and motor.
• The controller uses the battery power according to produce the input given by the motor to obtain maximum speed.
• The battery is also used to power every electrical component in the vehicle. The Battery block implements a generic dynamic model that represents most popular types of rechargeable batteries.
• The battery has two stage one is charging and another one is discharging state. The battery is of 630Ah capacity. The Nominal voltage of battery is 60 V.
• Initial SoC is of 100%.

The battery has a positive and negative terminal which is given the current controlled source where the battery consumption is controlled by the motor controller and then it is given to the SOC block.

• SOC is the percentage or level of battery presents after certain travel or consumption of battery charge by the vehicle.
• In the designed vehicle battery charge or SOC is calculated by the giving it to the rate transition and then to gain where 1/(nominal battery capacity) then to a discrete-time integrator and it will get minus from the 1 as it is considered a 100% of battery and it is multiplied with 100 to get percentage of battery.

• BUS Selector:

  • The Bus Selector block outputs the signals you select from the input bus. The block can output the selected elements separately or in a new virtual bus.
  • Here just we have mange the output and connect with different Scope Block.

  PowerGUI:

  • The powergui block allows us to choose one of these methods to solve your circuit:
  • Continuous, which uses a variable-step solver from Simulink.
  • Discretization of the electrical system for a solution at fixed time steps.
  • Continuous or discrete phasor solution.
  • The powergui block also opens tools for steady-state and simulation results analysis and for advanced parameter design.

  Driver Subsystem:

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• This block implements continuous- and discrete-time PID control algorithms and includes advanced features such as anti-windup, external reset, and signal tracking. You can tune the PID gains automatically using the tune button requires Simulink Control Design.

  Drive Cycle:

  • Drive cycle is assumed as the driver's input of a vehicle, it replaced how a driver will drive a vehicle.
  • Here I have used three drive cycles which is used to test the vehicle performances.
  • There are different drive cycles like WOT, FTP75 and through signal builder.

  Drive Cycle FTP75:

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• Generates a standard or specified longitudinal drive cycle.

  WOT:

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• Signal Builder:

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• Simulink Model:

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• • In this model we use three different drive cycles like WOT, FTP75 and through signal builder.
  • The Controller will follow the given drive cycle reference and run the motor in the required rpm.
  • The current flows to DC Motor from the battery through the DC-DC power converter to drive the motor. The required voltage will be controlled in the controller.
  • Then the motor power is transmitted to the wheels of a vehicle through the gear box, and the controller will take the vehicle speed and the speed of the vehicle is as given in drive cycle.

  Results:

  FTP75 Drive Cycle

  By running the vehicle with FTP75 drive cycle for 2474 sec the distance travelled is 17.76 km

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• • The actual Speed is approximately followed the 90% of reference Drive cycle.
  • The Temperature of Motor is 415°C.
  • The Temperature of Controller is≈ 500°C.
  • SOC decreases as 20%.

  WOT Drive Cycle:

  By running the vehicle with WOT Drive Cycle for 60 sec the distance travel by the vehicle is 0.4763

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• • The SoC% of the battery is reduced to 2% of 100 in 30 sec and after that 2% increase in another 30 sec.
  • The battery get charged by by back EMF.
  • The Temperature of Motor is
  • The Temperature of Controller is 298.15C .

  Signal Builder:

  The vehicle is running through signal builder for 200 sec and the distance is travelled is 2.472 km.

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• • The SOC% of the battery is reduced to 3% in 200 sec.
  • The Temperature of Motor is 304.2C.
  • The Temperature of Controller is 298.15C.

  Conclusion:

  In this project we compromised with the temperature of Motor and controller to achieve vehicle speed is near to reference speeds. Since we haven't used any cooling system in the model. In the real time application, the motor temperature is less than 100 C.

  In the real time application, the motor, battery & controller temperature is controlled by air cooling. Hence, the temperature of this components is not increased to this extent.

  And we created a MATLAB model of an Electric Rickshaw (three wheel passenger vehicle) by using Li-ion battery, PM Brushed DC Motor.

  Determined the variations of Temperature of Motor and controller, SoC% and Energy consumed by the by vehicle for all the three Reference Drive cycles (ie.; FTP75, WOT, Signal Builder).