Final Project: Electric Rickshaw modelling

Aim: To design an E - Auto Rickshaw Model by using the MATLAB Simulink.

ABSTRACT: In this project, we going to build the MATLAB model of the ELECTRIC RICKHAEW by using a PM brushed type DC motor and a suitable Lithium-Ion battery for the motor. Before that, we will know about what is Electric RICKHAEW, how it's works and the benefits of EV RICKHAE. Then we make an actual EV RICKHAEW model in SIMULINK with suitable blocks from the powertrain block set. My main motto is to check "how my RICKHAEW performs for any three standard driving cycles showing energy consumption, the temperature rise of motor and controller for vehicle cover around 100 km at constant speed driving 45 kmph. Made a comparison with Mahindra e-Rickhaew and my Simulink model.

Objectives:

• 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.

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, controlled, 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 or by using Excel.

Specifications of E-Rickshaw:

• Battery Type Lithium Ion 330 V 75

• Vehicle kerb weight 260 kg & 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 75 Ah

• Initial SOC % 100

• Internal Resistance 5 ohm

Now we will come to the SIMULINK model and subsystems inside it.

Longitudinal Driver:

• This is the block from where all the inputs will be fed to motor and wheels in a vehicle to move.

• It is a parametric longitudinal speed tracking controller for generating normalized Acceleration and Braking commands based on reference and feedback velocities.The VelFdbk port corresponds to the feedback velocity.

• The actual velocity output given by the vehicle body is connected here.

• By comparing the actual (feedback) velocity with the reference velocity, the driver block generates acceleration and braking signals in order to minimise the error between the two concerned velocities.

• Grade corresponds to the grade angle. For this simulation, no inclination is considered and hence, a constant block with value 1 is connected.

• Info gives the output for the bus signal for different block calculations like difference in reference vehicle speed and vehicle speed, etc.

• AccelCmd & DecelCmd correspond to the acceleration and deceleration commands generated respectively and are connected to the corresponding ports of the Controlled PWM Voltage block.

  Here, the selected control type is Pl. Acordingly, the block implements proportional-integral (PI) control with tracking windup and feed-forward gains.

Signal Builder:

• Here we have considered a FTP75 Drive cycle source which can be runned for 2474 sec as mentioned in the block over here

Controller:

• Here we have used H-Bridge which is used for a Motor Drive
• We have also considered hte thermal port in order to maintain ans simulate the vehicle with real time parameters

Necessary parameters that are modelled for 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.

PWM modulator to supply the required power to run the PM DC Motor

Temperature sensor is used to sense the temperature that is being produced while H-Bridge is being operated.

Current sensor is the block that is used to calculate current that is being consumed by the DC motor while running the vehicle.

Motor:

• This block represents the electrical and torque characteristics of a DC motor includes Thermal port to sence 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 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.

Here we have considered the Permanant Magnet DC Motor as given in the requirements.

• TheMotor controller will get input from the longitudinal driver. Its tasks are to control the speed of the motor and drive according to the input of the driver.
• Majorly motor controlledwe designed had two main parts named PWM voltage generator and H-Bridge.
• Input 1 is getting from the accelmd of a longitudinal driver and it is given to a controlled voltage source block where it is input to the controlled PWM voltage.
• Controlled PWM voltage will generate a PWM signal in such a way that H-bridge will generate the required voltage to operate the DC motor for the given driver input.
• PWM voltage block negative reference and REF are grounded and REF of H-bridge respectively.
• H-bridge is a motor controller that has IGBT components aligned in the shape of H and will operate only two at a time respectively to the input of the signal from the PWM block.
• When deceleration occur this Hbridge will give an output from the positive and negative terminals of it.
• These negative & positive terminals are later connected to the DC motor and battery.

Wheels:

• 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.

Vehicle body is the block where all the wheels are connected and necessary parameters fed to the block to run the vehicle

These are the parametric values that are given with respect to the specifications we have considered for the vehicle

This is the Tire(Magical Formula) that is ued as a wheel for the E-Rickshaw

• 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.

This is the rotational Free end which is connected to the front wheel as there in no 4th wheel that can be connected

Here both Right and Left Rear Wheels are connected to a common axle where the simple gear is also connected for transimission of mechanical energy that came from DC Motor.

Simeple gear is used to transmit the power

Here we have fixed the gear ration as 5 for transmission.

Distance Covered:

Here we have integrated the output vehicle speed so that we will get the distance that is travelled by the vehicle during simulation.

Battery:

Here we have considered a Li-ion Battery to fees power to the DC motor.

There are the parameters fed as per the name plate details we have considered.

SOC:

Here we hae used Rate Transition --> Gain --> Discrete Time Integrator --> Gain to calulate the SOC of the battery while we are draining it during simulation

Now we will have a look at the following outputs from the vehicle:

Distance Travelled:

SOC and Current:

Vehicle Speed:

Motor & Controller Temperatures:

Here we can observe that as the vehicle moves forward in a continous acceleration mode with respect to drive cycle the motor and controller temperatures are keeps on increasing.

• Here motor temperature reached to a level of ~360C and controller temperature to ~ 298C
• Max velocity os vehicle is nearly 25kmPH
• SOC of battery reached to ~63%