Final Project: Electric Rickshaw modelling

AIM:- Create a detailed MATLAB model of an electric rickshaw (three wheel passenger vehicle).

OBJECTIVE:-

• 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.

E- Rikshaw:-

Electric rickshaws (also known as electric tuk-tuks or e-rickshaws or toto or e-tricycles) have been becoming more popular in some cities since 2008 as an alternative to auto rickshaws and pulled rickshaws because of their low fuel cost, and less human effort compared to pulled rickshaws. They are being widely accepted as an alternative to petrol/diesel/CNG auto rickshaws. They are three-wheelers powered by an electric motor ranging from 650 to 1400 Watts. They are mostly manufactured in India and China. Battery-run rickshaws could be a low-emitter complementary transport for the low-income people, who suffer most from a lack of transport facility, if introduced in a systematic manner according to experts.

MODEL:-

subsystems:- power controller, motor & gear, battery pack & SOC, vehicle dynamics subsystem.

MODEL parameters:-

Drive cycle:-

drive cycle is the input by driver to run the vehicle in different situation or conditions, in which speed of vehicle will get high, low or stops. here we have use three different drive cycle to test the E-rikshaw, that are FTP75, WOT, manual spreadsheet. as shown above a constant block is connected, in this the sequence no. we put that perticular drive cycle gets selected.

block use:- multi port switch, constant, drive cycle, from spreadsheet.

multiport switch-

here multiport switch is use as selector, to select only one drive cycle at atime according to the port no. put in constant as shown in model.

drive cycle ftp75-

as per the objective using three standard drive cycle, one of the drive cycle source is FTP75 & the parameter s setting is shown below.

wot drive cycle-

the parameters are set as per the objective, to run vehicle for 100 km with constant 45km/s.

spreadsheet-

below link is for manual drive cycle spreadsheet use in this model.

LINK:- https://docs.google.com/spreadsheets/d/1Xgte3X63b8yOGg5UJtv3mbjUMU7yy0nk/edit?usp=sharing&ouid=100881527095844999457&rtpof=true&sd=true

longitudinal Driver-

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.

as shown above longitudinal block is connected in model, velocity reference is connected to drive cycle as input, output velocity of vehicle generated by vehicle dynamics subsystem is input to driver velocity feedback. acceleration & deacceleration command from driver input to power controller subsystem using simulink ps converter block as shown.

POWER controller subsystem:-

In this subsystem controlled PWM voltage & H-bridge is use as shown, work as DC drive to control the speed of vehicle, the output of H-bridge is +ve & -ve which control the DC motor, we have use thermal port of H-bridge to measure temperature of controller.

block use- controlled pwm voltage, H-bridge, current sensor, controlled voltage source, solver configuration, thermal reference, electrical reference, ps-simulink converter, goto.

H-bridge block-

This block represents an H-bridge motor drive use as DC-DC converter. 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 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.

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 value equal to the averaged PWM signal.

output voltage amplitude is taken as 5v.

thermal reference-

This block represents a reference point in a thermal network where the temperature is equal to absolute zero.

Motor & gearbox subsystem-

block use- DC motor, thermal reference, mechanical rotational reference, thermal reference, goto, ps-simulink converter.

to attach thermal port, click on the block, then click simscape block, then block choice select show thermal port.

DC motor-

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.

Vehicle dynamics subsystems-

block use- vehicle body, tire(magic formula), simple gear, inertia, rotational free end, simulink-ps converter, constant, ps-simulink converter, goto.

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.

simple gear-

Represents a fixed-ratio gear or gear box. 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 setting Friction model to a temperature-dependent setting.

Inertia- The block represents an ideal mechanical rotational inertia.The block has one or two mechanical rotational conserving ports. The difference is purely graphical, as the ports are rigidly linked. The block positive direction is from its port to the reference point. This means that the inertia torque is positive if the inertia is accelerated in the positive direction.

Tire (Magic Formula)-

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.

rolling resistance= 0.2 meter

velocity thresold= 0.1 m/s

Batterypack & SOC system-

Here battery used is lithium ion which is very efficient as compare to others, battery is connected to power controller to give power to motor to run, energy consumption is also been calculated, current per sec & voltage per sec multiply & divide by 3600sec to get Watt hour as shown above.

block use- battery, bus selector, controlled current sourse, powergui, product, integrator, divide, constant, scope, display, ps-simulink converter.

Battery- Implements a generic battery model for most popular battery types. Temperature and aging (due to cycling) effects can be specified for Lithium-Ion battery type.

Bus selecter-

This block accepts a bus as input which can be created from a Bus Creator, Bus Selector or a block that defines its output using a bus object. The left listbox shows the elements in the input bus. Use the Select button to select the output elements. The right listbox shows the selections. Use the Up, Down, or Remove button to reorder the selections. Check 'Output as virtual bus' to output a single bus.

controlled current source-

power consumption(Wh)-

Distance calculator-

output of vehicle dynamics i.e velocity of vehicle is in km/h, to get distance in km we have to divide the velocy by 3600sec, as shown below.

LINK:- https://drive.google.com/file/d/1Zpzdp2cmYvPuaRh5nXg4cf3Ry4DGEHDO/view?usp=sharing

RESULT:-

1) For FTP75 Drive cycle-

• on selecting this drive cycle & run the simulation for 2474 sec, the vehicle will cover 15.78 km as shown, the max. velocity reached was 91km/sec.
• the motor temperature reach to 176 degC at the end.
• the controller temperature reach to 250 degC at 1500sec to 2000sec constant, after that temp. got increase due to sudden changes of duty cycle, which increase the load in power converters switching.
• SOC of becomes zero% at 2338sec, from 1500sec to 2000sec the battery state was 28% charge constant due to constant speed.
• energy cosumption is 22.605 kwh throughout the simulation.

the above result show the drive cycle & the actual setpoint covered by vehicle, we cannot get 100 % same as drive cycle.

Motor temperature-

Controller temperature-

SOC-

2) For WOT Drive cycle-

• In this drive cycle & simulation time is 9000 sec, to run the vehicle for 100 km in 45km/h constant velocity, we can see the result, distance covered is 99.95 km with constant speed of 45 km/h. as we can see the parameter setting of WOT drive cycleafter 100 sec the speed will reach to 45km/sec constant for 8100sec to cover 100 km. [45*(8100-100)/3600sec = 100km]
• the motor temperature reach to 276 degC at 2474 sec.
• the controller temperature reach to 350 degC at 2000sec, after that temp. getting increase linearly due to constant of duty cycle, which increase the load in power converters switching.
• SOC of becomes zero% at 1220sec, from 100sec to 1220sec the battery state gets reducing linearly constant due to constant speed.
• energy cosumption is 23.484 kwh throughout the simulation.

Motor temperature-

controller temperature-

SOC-

3)For spread sheet-

• this drive cycle is for 200sec, so running simulation for 200 sec it cover 1.905km as shown.
• the motor temp. reaching to 42degC at the end.
• controller temp. reach to 71degC at the end.
• SOC is about 83% charge at 200sec.
• energy consumed is 3.701 kwh.

SOC-

Motor temperature-

controller temperature-