Final Project: Electric Rickshaw modelling

AIM :  Design of an Electric Rickshaw using 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 works, and its 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 between Mahindra e-Rickhaew and my Simulink model.

 

OBJECTIVES :

Create a detailed MATLAB model of an electric rickshaw (ththree-wheel passenger vehicle) as per dethe tails below : 

• Rear wheels driven by PM brushed type motor
• Assume the ficiency points othe f motor controller and motor
• Make an excel sheet of all input and assumed data 
• Results: For any three standard driving cycles show energy consumption, the temperature rise of motor and controller for 100 km constant speed driving at 45 mph.

 

METHODOLOGY:

• The electric vehicle consists of a battery, motors, and controller then it generates propulsion power.
• To design any vehicle 1st we have to calculate propulsion power, then the motor is selected.
• Lastly based on the motor rating or operating range and no km/charge we want to depend on everything battery capacity and then battery capacity is selected. So the Design flow of the ehvehiclengineer has to be like the following :

• Identify what amount of propulsion power required.
• What is the best suitable motor for that propulsion power.
• Then type of battery and range of battery according to the range.

 

  

INTRODUCTION :

• Electric E-Rickshais alsoso known as an electric ttuk-tuks e-rickshaw and auto which are going more popular after 2018 the in ItheIndiann market. This E-rickshaw is the best alalternativeftoetrolto/ CNG toauto rickshaws and human orhorse-pulledd rickshaws because of their low fuel cost, zero emissions, and fewer humanefforts.
• The electrical system used in Indian version is 48VDC can run 90– 100 km/full charge, top speed 2of 5 km/hour and this electric motor power ranging from 650-1400 Watts; the battery takes 8–10 hrs to become fully charged. The basic seating capacity is driver plus 4 passenger total 5 persons.
• Here basically, the e-rickshaw is designed in CREO and MATLAB Simulink. In the designed electric rickshaw main blocks the are battery, drive cycle, controlled, DC Motor, Vehicle body, and transmission system driver cycle is the input of human effort that how he is going to drive his actual cycle. We can use cycles cycle like FTP75, WOT or by using Excel.
• The main objective of this project is to obtain speed by the driver, to estimate the temperature of motor and controller, and to estimate the state of charge (SOC) and distatraveledavel by the vehicle. There is a SOC block that will estimate the state of charge of the battery, and distance is calculated by speed and time parameter for all three Drive cyclcycles

 

 

Design and Construction :

• These rickshaws have an M.S. (Mild Steel) tubular chassis, consisting of three wheels with a differential mechanism at the rear wheels. The motor is a brushless DC motor manufactured mostly in India and China. The electrical system used in the Indian version is 48V and in Bangladesh is 60V. The body design from the most popular Chinese version is of very thin iron or aluminum sheets. Vehicles made in fiber are also popular because of their strength and durability, resulting in low maintenance, especially in India.
• The body design is varied from load carriers, passenger vehicles with no roof, to full body with windshield fodrivers'rs comfort. It consists of a controller unit. They are sold based on the voltage supplied and current output, also the number of MOSFET (metal oxide field-effect transistors) used. The battery used is mostly a lead-acid battery with a life of  6–12
  months. Deep cycle batteries designed for electric vehicles are rarely used. The weight of the electric car has also been a recurring design difficulty in them.

 

 

 

General detail of E-Rickshaw -

• Battery Type Lithium Ion 330 V 75 Ah
• Vehiclcurbrb weight 260 kgs
• Load capacity 34kggs
• Vehicle speed 7mphh
• 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

 

 

PROCEDURE :

(1) Vehicle Body Subsystem Model :

• 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 the tires.
• Below is a diagram that is how it is it 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 Reathe r tires, in the circuit it is shown that the gear is connected to the  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 vehbody's body normal force port.
• The vehicle body has an H-Hub, S- Tire slip, N- Normal force, A- axel connection, wind velocity, and inclination angle. The tireires 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 he get the distance traveled and the state of charge.

Vehicle Body Parameters :

• Vehicle body mass, Centre of gravity distance values, and aerodynamic drag variables are modified.
• Pitch dynamics are kept ON with other variable values as default values.

 

Tire :

• 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.

• 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.

 

Gear :

• Represents a fixed-ratio gear gearbox. No inertia or compliance is modeled in this block. You can optionally include gear
  meshing and viscous bearing losses.

• 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. Output shaft rotates in samthe e directional input shaft.
• Base is connected to the Motor shaft and the follower is connected to the Rear wheel derive.

 

Vehicle Body :

• This block basically 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 t to he acceleration road profile.
• Here, the connection H is the mechanical translational conserving port hub. NF & NR correspond to the output ports' normalmral reaction forces on the 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 the vehicle). The gross weight is given to be 600 kg.
• The geometric parameters of the vehicle are given as -

 

 

(2) Motor & Power Converter Subsystem Model (With Temperature Sensor) :

 

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.

 

DC Motor :

• This block represents the electrical and torque characteristics of a DC motorincludings a Thermal port to sence the temperature othe f the 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 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 positiveflowsrent 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.
  

   

  
• 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 controlled we 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 thean  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 its positive and negative terminals of it. These negative & positive terminals are later connected to the DC motor and battery. All these components are the simscape electrical components so they need a connection to the solver configuration block which helps to solve the simulation.

 

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.
• 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.
  
  
•  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 a value equal to the averaged PWM signal. Select Simulation mode as Averaged.

 

Temperature Sensor :

• Temperature Sensor is used to mesure the temperature othe f 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.

 

Solver Configuration :

Defines solver settings to use for simulation.

 

 

(3) 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 represethe nts most popular types of rechargeable batteries.

• The battery has two stage one is charging and another one is discharging state. The battery is of 75Ah capacity.
  The Nominal voltage of the battery is 330 V
  Initial SoC of 100%
  The battery has a series s internal resistance plus a charge-dependent voltage source defined by :
  $V=\frac{Vnom\cdot SoC}{1-\beta \cdot (1-SoC)}$

• where SoC is the state of chargeVenom Vnom is the nominal voltage. Coefficient beta is calculated to satisfy a user-defined data point [AH1,V1].
• The battery has a positive and negative terminal which is given the voltage-controlled source where the battery consumption is controlled by the motor controller and then it is given to the SOC block.

 

Battery State of Charge :

• SoC is the percentage or level of battery present after certain travel or consumption of battery charge by the vehicle.
• In the designed vehicle battery charge or SOC is calculated by 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 perca entage of battery.
• The majority of blocks are simscape blocks where physical to simulink converter is used to convert the physical signal from simscape block to simulink signal.

 

Controlled Current Source :

The Controlled Current Source block converts the Simulink input signal into an equivalent current source. The generated current is driven by the input signal of the block. The positive current direction is shown by the arrow in the block icon.

We can initialize the Controlled Current Source block with a specific AC or DC cuDCwe want to start the simulation in steady state,  a block input must be connected to a signal starting as a sinusoidal or DC waveform corresponding to the initial values.

• Double click controlled current source and from the drop-down menu of measurement select current.
• Signal output will connect with scope by adding the current signal to it.
• (+) terminal will connect with battery (-) terminal.

 

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 hmanageange the output and connect with different Scope Block.

 

PowerGUI :

The powerful 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.

PID CONTROLLER:

block parameter:

(5) Reference Velocity (Drive Cycle) :

 

block parameter:

• 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 are used to test the vehicle's performance. These drive cycles will have high speed, low speed, and braking conditions in it.
• There are different drive cycles like  FTP, UDDS,SIGNAL BU, ILDE, R et c., Here in this model I have used FTP 75, and WOT & Manually prepared in excel Drive Cycle source.

 

 

 simulink model of an electric rickshaw:

 

RESULT:

SCOPE:

           

scope dc motor output for the scpe in 100sec (98.551)

battery output 1 is 297rpm in 100second

battery output2 in 100sec(99.the 572)

sum is connecteed to the scope in 0-100

 

 

Simulink Explanation :

• Initially the current flowflowDC Motor from the battery through the DC-DC power converter to drive the motor. The required voltage will be controlled in the controller. The Controller will follow the given drive cycle reference and run the motor at the required rpm.
• Then the motor power is transmitted to the wheels of a vehicle through the gearbox. and the controller will take the vehicle's speed and compare and controlled.

 

 

CONCLUSION :

• Here I have compromised with the temperature of Motor and controller to achieve vehicle speed year to reference speeds. Since I haven’t used any cooling system in the model. In the realreal-timelication, the motor temperature is less than 100 C.
• In the realreal-timelication, the motor, battery & controller temperature is controlled by air cooling. Hence, the temperature of this components is not increased to this extent.
• Hence, Created a MATLAB model of an Electric Rickshaw (three-wheel passenger vehicle) by using Li-ion battery, and PM Brushed DC Motor.
• Detremined the variations of Temperature of the Motor and controller, SoC% and Energy consumed by the by vehicle for the three Reference Drive cycles (i.e.; FTP, SIGNAL, UDDS, Manually prepared).
• This Battery powered Rickshaw will be the most popular mode of transport in the future.
• final results as been explain in details.