Projects:2015s1-73 Improved Electric Micro-Bus Design for Nepal

Project 73, titled Electric Vehicle Design and formerly known as Improved Electric Micro-Bus Design for Nepal, consists of group member Lukas Matthews, Jia Yi Lim, Michael Thompson, and Jinyi Lu.

Throughout 2015, Project 73 memebers have looked at the various elements that combine to make practical and functional electric vehicles. Initially the team focussed on improving the "Safa Tempo", an existing electric powered, three wheeled, ten-seater electric taxi that currently operates in Kathmandu, Nepal. Investigation into the shortcomings of this existing technology and the possible performance increases that could implemented was conducted in the first half of the year. However, due to a lack of funding and the horrific earthquake that struck Nepal on the 25th April 2015, it was decided that implementation of this project was no longer possible. From there the team contacted Dr Nesimi Ertugrul who offered to supply the team with the necessary funding to successfully convert his 2003 Mazda MX5 into an electric vehicle. With the help of Dr Carsten Marksgraf, the team was able to investigate the best possible modification methods and was able to successfully implement an Infineon HybridKit1 - PinFin as well as a Toyota Prius MG2 motor into the Mazda vehicle. File:Picture1.jpg

Background

This project aims to convert an existing internal combustion engine (ICE) vehicle, 1993 Mazda MX-5 into a fully functional electric vehicle. As a part of the on-going project, focus for this year is to implement a 50kW Infineon HybridKIT1 Pin Fin controller into the car. A vehicle controller drives electric motor by converting battery energy into appropriate forms which corresponds to the driver’s command.

The project is highly motivated by the increasing global concern on vehicle greenhouse emission. ICE vehicles source its energy from combustion of fuels, which produces harmful gas such as carbon dioxide, nitrogen oxide and carbon monoxide. As for electric vehicles, chemical batteries are the source of energy and it does not yield any harmful emissions.

Objectives

Functional inverter with Field Orientated Control (FOC)

Phase current monitoring with the use of current sensors

Data logging via CAN Bus

System integration

A vehicle with running wheels, controlled by a throttle

Controller

A controller is connected to the battery system. Controller converts DC input from battery system into a controlled AC output in order to drive the electric motor.

Torque of an electric motor has to be controlled during normal driving conditions to maintain vehicle speed. This can be done by controlling the rotor’s mechanical speed and phase currents. 𝑇=3/2 𝑝(𝜑∙𝑖_𝑞+(𝐿_𝑑−𝐿_𝑞)∙𝑖_𝑑∙𝑖_𝑞)

FOC is the process of controlling the stator current vector in the (d,q) reference frame, based on Clarke and Park Transform.

CANBus

Various on-board computing devices are usually installed inside an electric vehicle. CAN bus is a serial bus communication used to support real time vehicle data exchange in a closed loop system. Lauterbach JTAG Debugger was initially used for such purpose but it is highly prone to electromagnetic interference (EMI) issues. NI USB 8473-s CAN bus device is used for this project. Receive function was developed to read values from controller such as voltage, current, position, and temperature. Software used for the development is MATTLAB.

Result

Outcomes for this project are:

Controller is installed into the car

FOC is functioning

Field weakening

CAN bus is able to receive and display readings from the controller

Implementation of controller, CAN bus and cooling system hardware into the vehicle.

Future Work

Battery pack upgrade

Battery management system (BMS)

Motor upgrade with regenerative braking

Send function for CAN bus