Final Project: Electric Rickshaw modelling
Projetect:- 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.
(Note- The simulink model file should be compulsorily attached)
Answer:-
Aim:- To design Mahindra Treo E-Rickshaw using matlab simulink.
Model Specifications given:-
Calculation of Total force and Power:-
| Vehicle Power Requirement Calculations | |||||
| E-Rickshaw | |||||
| Rolling resistance calculation | |||||
| Kerb weight(kg) | 377 | ||||
| Payload(kg) | 250 | ||||
| Coefficient of rolling resistance | 0.015 | ||||
| Rolling resistance force(N) | 92.26305 | (coefficient of rolling resistance*(kerb weight+payload)*g | |||
| Air Drag Calculation | |||||
| Air Desnsity(kg/m3) | 1.25 | ||||
| Width(m) | 1.765 | ||||
| Height(m) | 1.595 | ||||
| Frontal Area(m2) | 2.815175 | ||||
| Drag Coefficient | 0.33 | ||||
| Speed(kmph) | 55 | Top speed is 55kmph | |||
| Velocity(m/s) | 15.27777778 | ||||
| Air Drag Force(N) | 135.5250986 | (air density*frontal area*drag coefficient*velocity^2) | convert speed from kmph to m/s | ||
| Total power(rolling+air drag) | 3480.096714 | (rolling resistance force+Air drag force)*velocity | |||
| Hill Climbing calculation | |||||
| Angle(degrees) | 10 | ||||
| Angle(radians) | 0.174444444 | ||||
| Speed during hill climbing | 20 | ||||
| Velocity(m/s) | 5.555555556 | ||||
| Force(N) | 1067.551397 | (m*g*sin(angle) | |||
| Hill vlimbing power(kW) | 5.930841094 | (Force*velocity) | |||
| Acceleration Power Calculation | |||||
| final speed from 0 to xkmph) | 20 | ||||
| Velocity(m/s) | 5.555555556 | ||||
| Acceleration time(sec) | 2.3 | 806.3271605 | |||
| Acceleration(m/s2) | 2.415458937 | (a=velocity/acceleration time) | |||
| Acceleration force(N) | 8413.848631 | F=m*a*v | |||
| Acceleration Power(kW) | 806.3271605 | P=(0.5*m*V^2)/acceleration time | |||
| Total Force(N) | 9709.188177 | ||||
| Total Power(W) | 4292.354716 | ||||
| Total Power (kW) | 4.292354716 | ||||
Step 1:- Designing of Vehicle (Load on motor)
Parameter settings:-
1)Vehicle Body:-
Total mass takes(Kerb weight + Paayload)
The Vehicle Body block represents a two-axle vehicle body in longitudinal motion. The vehicle can have the same or a different number of wheels on each axle. For example, two wheels on the front axle and one wheel on the rear axle. The vehicle wheels are assumed identical in size. The vehicle can also have a center of gravity (CG) that is at or below the plane of travel.
The block accounts for body mass, aerodynamic drag, road incline, and weight distribution between axles due to acceleration and road profile. Optionally include pitch and suspension dynamics. The vehicle does not move vertically relative to the ground.
The block has an option to include an externally-defined mass and an externally-defined inertia. The mass, inertia, and center of gravity of the vehicle body can vary over the course of simulation in response to system changes.
2)Tire
1)Tire (Magic Formula)
The Tire (Magic Formula) block models a tire with longitudinal behavior given by the Magic Formula [1], an empirical equation based on four fitting coefficients. The block can model tire dynamics under constant or variable pavement conditions.
The longitudinal direction of the tire is the same as its direction of motion as it rolls on pavement. This block is a structural component based on the Tire road interaction block.
To increase the fidelity of the tire model, you can specify properties such as tire compliance, inertia, and rolling resistance. However, these properties increase the complexity of the tire model and can slow down simulation. Consider ignoring tire compliance and inertia if simulating the model in real time or if preparing the model for hardware-in-the-loop (HIL) simulation.
3)PS Terminator
Use the PS Terminator block to cap physical signal output ports that do not connect to other blocks
4)PS Constant
The PS Constant block generates a physical signal of a constant value. You specify the value and unit of the signal as the Constant parameter.
5)Inertia
The Inertia block represents an ideal mechanical translational inertia that is described with the following equation:
T=Jdωdt
where:
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T is inertia torque.
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J is inertia.
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ω is angular velocity.
-
t is time.
6)Simple Gear
The Simple Gear block represents a gearbox that constrains the connected driveline axes of the base gear, B, and the follower gear, F, to corotate with a fixed ratio that you specify. You choose whether the follower axis rotates in the same or opposite direction as the base axis. If they rotate in the same direction, the angular velocity of the follower, ωF, and the angular velocity of the base, ωB, have the same sign. If they rotate in opposite directions, ωF and ωB have opposite signs. You can easily add and remove backlash, faults, and thermal effects.
Step 2:- DC motor and Converter
1) DC Motor
The DC Motor block represents the electrical and torque characteristics of a DC motor using the following equivalent circuit model:
Parameter Settings:-
2)H-Bridge
The H-Bridge block represents an H-bridge motor driver. The block has the following two Simulation mode options:
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PWM— The H-Bridge block output is a controlled voltage that depends on the input signal at the PWM port. If the input signal has a value greater than the Enable threshold voltage parameter value, the H-Bridge block output is on and has a value equal to the value of the Output voltage amplitude parameter. If it has a value less than the Enable threshold voltage parameter value, the block maintains the load circuit using one of the following three Freewheeling mode options:-
Via one semiconductor switch and one freewheeling diode -
Via two freewheeling diodes -
Via two semiconductor switches and one freewheeling diode
The first and third options are sometimes referred to as synchronous operation.
The signal at the REV port determines the polarity of the output. If the value of the signal at the REV port is less than the value of the Reverse threshold voltage parameter, the output has positive polarity; otherwise, it has negative polarity.
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Averaged— This mode has two Load current characteristics options:-
Smoothed -
Unsmoothed or discontinuous
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You specify the equivalent circuit parameters for this model when you set the Model parameterization parameter to By equivalent circuit parameters. The resistor R corresponds to the resistance you specify in the Armature resistance parameter. The inductor L corresponds to the inductance you specify in the Armature inductance parameter.
Parameter Settings:-
3) Controlled PWM Voltage
The Controlled PWM Voltage block represents a pulse-width modulated (PWM) voltage source. You can model electrical or physical signal input ports by setting the Modeling option parameter to either:
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Electrical input ports— The block calculates the duty cycle based on the reference voltage across its ref+ and ref- ports. This option is the default. -
PS input— Specify the duty cycle value directly by using an input physical signal port.
If you set Modeling option to Electrical input ports, the demanded duty cycle is
100∗Vref−VminVmax−Vmin percent
where:
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Vref is the reference voltage across the ref+ and ref- ports.
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Vmin is the minimum reference voltage.
-
Vmax is the maximum reference voltage.
Parameter Settings:-
4)Controlled Voltage Source
The Controlled Voltage Source block represents an ideal voltage source that is powerful enough to maintain the specified voltage at its output regardless of the current flowing through the source.
The output voltage is V = Vs, where Vs is the numerical value presented at the physical signal port.
The block has one physical signal input port and two electrical conserving ports associated with its electrical terminals.
5)Current Sensor
The Current Sensor block represents an ideal current sensor, that is, a device that converts current measured in any electrical branch into a physical signal proportional to the current.
Use the + and - ports to connect the sensor in series with the other blocks in the branch where you want to measure the current. Port I outputs the measurement result as a physical signal.
6)Solver Configuration
Each physical network represented by a connected Simscape™ block diagram requires solver settings information for simulation. The Solver Configuration block specifies the solver parameters that your model needs before you can begin simulation.
Each topologically distinct Simscape block diagram requires exactly one Solver Configuration block to be connected to it.
7)Electrical Reference
The Electrical Reference block represents an electrical ground. Electrical conserving ports of all the blocks that are directly connected to ground must be connected to an Electrical Reference block. A model with electrical elements must contain at least one Electrical Reference block.
Step3) Longitudinal Driver
The Longitudinal Driver block implements a longitudinal speed-tracking controller. Based on reference and feedback velocities, the block generates normalized acceleration and braking commands that can vary from 0 through 1. You can use the block to model the dynamic response of a driver or to generate the commands necessary to track a longitudinal drive cycle.
Parameter Settings:-
Step4)Drive Cycle
Parameter Settings:-
Step5)Battery SOC
1)Battery
Generally in electric vehicle we are using 48V battery.
Parameters Settings:
Overall System :-
Results and Discussion:-
Reference and Actual Speed:-
The above graph shows the reference speed and actual speed of vehicle. We can see that the vehicle is almost follwoing the reference. The performance can be enhanced by designing the proper controller for the system.
Battery SOC, Current & Voltage and Motor outbut volatge:-
Above graph shows the value of state of charge of battery, Battery current and battery voltage. Also we can see the motor output volatge.
Now repeat the same for WOT drive cycle:-
The following graph shows the reference speed and actual speed. We can observe that the actual speed is almost follwoing the referce. The performance can be enhanced by designing the propwer controller.
Battery SOC, Current Volatge and Motor Volatge:-
Conclusion:-
Here we simulated E rickshaw. The rating of E rickshaw is 48V. We have calculated the power and force requirement. After that we prepared the simulation model as per the rating decided for e Rickshaw. After that we tried to adjust the parameters such that we will get the proper response. We can observe that the actual speed of vehicle is follwing the reference speed. The error can be enhanced by designing the proper controller for the system. Also we have tried to simulate for FTP and WOT drive cycles.