Final Project: Electric Rickshaw modelling
Final Project: Electric Rickshaw Modelling
Aim:
To create a detailed MATLAB model of an electric rickshaw (three-wheel passenger vehicle) as per details.
Objectives:
The vehicle has to be modelled with rear wheels driven by PM brushed type motor.
Efficiency points of motor controller and motor have to be assumed, excel sheet has to be prepared with the assumed data and all input
For any three standard driving cycles show energy consumption, the temperature rise of the motor and controller for 100 km constant speed driving at 45 kmph.
Introduction:
Electric rickshaws 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 fuel rickshaws. They are three-wheelers powered by an electric motor ranging from 650 to 1400 watts. They are mostly manufactured in India and China, only a few other countries manufacture these vehicles. Battery-run rickshaws could be a low-emitter complimentary transport for the low-income people, who suffer most from a lack of transport facility if introduced in a systematic manner according to experts.
E-Rickshaw's have now transitioned from being a market entrant in the automobile segment of the country to evolve as a leading short distance transport solution. The share of E-Rickshaws in India is represented below,
The electrical system used in the Indian version is 48V. Vehicles made in fibber are 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 windshields for drivers' comfort. These rickshaws have a mild Steel tubular chassis, consisting of three wheels with a differential mechanism at the rear wheels.
It consists of a controller unit. They are sold on the basis of voltage supplied and current output, also the number of metal oxide field-effect transistors used. The battery used is mostly a lead-acid battery with a life of 6–12 months.
Model and explanation
The Simulink model of electric rickshaw is uploaded to google drive and the access link to the file is https://drive.google.com/file/d/1wPW3_M2D-FNWOUI5XPb8JpXpWNskEXY2/view?usp=sharing
Drive Cycle: Every vehicle needs a drive cycle so that we can simulate the performance. It will act as a drive input for the iterations. The drive cycle system which was created is given below. It consists of three drive cycle sources. These blocks are connected to a multiport switch so that we can select one of them. Drive cycle source block generates a standard longitudinal drive cycle. The block output is the vehicle's longitudinal speed. UDDS drive cycle is loaded from the workspace. Data of the cycle is stored in an excel sheet and it is loaded to a workspace with the import command. The link for the datasheet and mat lab file is
https://drive.google.com/file/d/1I9m5n3sArlLZ-Q0PijF22lLiPxIdGI7Q/view?usp=sharing
Longitudinal Driver: It is a parametric longitudinal speed tracking controller for generating normalized acceleration and braking commands based on reference and feedback velocities. We have already given the reference velocity as the drive cycle. In this block, we can add any grade values if we want. Acceleration and braking outputs are connected to motor control units.
Motor & Controller: This subsystem drives the shaft according to the input of the driver. The representation of the subsystem is given below.
Here we used a DC motor to power the model. 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 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.
DC motor is controlled by an H bridge block. Conditions for the H bridge block are given below.
The block can be driven by the Controlled Pulse Width Modulator (PWM) Voltage block. We selected the average mode for the PWM block. 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. We kept the Simulation mode parameter value for the Controlled PWM Voltage and H-Bridge blocks the same. 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. The PWM block will keep the output voltage zero when the pulse is low, and equal to the output voltage amplitude parameter when high.
The duty cycle is set by the input value. A controlled current source is given to the modulator so that the power will not be used uncontrollably. The battery is also connected to the DC motor with a monitoring system for the battery.
Temperature sensors are connected to the DC motor and H Bridge for their temperature monitoring. This block measures temperature in a thermal network. Output results like temperature from sensor, soc, and energy consumption from the battery are connected to scope with from goto blocks.
Vehicle
The vehicle body block 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. Connection H is the mechanical translational conserving port associated with the horizontal motion of the vehicle body. The resulting traction motion developed by tires is 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. Connections W and beta are physical signal input ports corresponding to wind speed and road inclination angle, respectively.
Gear input is given to the wheel blocks. We will get the vehicle velocity from the output port and it is given to the longitudinal driver block as feedback velocity. The feedback and reference velocities are connected to a scope block so that we can compare them. Output velocity is also integrated and converted to distance in kilometers by an integrator block. Parameters were concluded in an excel sheet and the link is https://docs.google.com/spreadsheets/d/1qR-8EEOTUwl52ztgQW-vp-tD9a2cT7FL/edit?usp=sharing&ouid=115627123808081772362&rtpof=true&sd=true
Results:
FTP75
WOT
UDDS
Conclusions:
MATLAB model of an electric e-Rickshaw model has been created and simulated successfully for three different drive cycles, and obtained results are observed. From the obtained results, when compared FTP75 drive cycle exhibits the highest distance covered, and it’s the most efficient cycle. State of Charge decreases and temperature increases with respect to the input throttle given.