THE ELECTRIC AUTOMOTIVE MOTOR CONTROL SYSTEM

Transcription

1 THE ELECTRIC AUTOMOTIVE MOTOR CONTROL SYSTEM Timothy E. Jackson Project Proposal October 30, 2003 ETec 471, Morton Western Washington University Department of Engineering Technology.

2 INTRODUCTION In today s world the need to research alternative energy for transportation has been pushing the automotive community away from traditional fossil fuels. Paving the way, in this research, is the Vehicle Research Institute (VRI) of Western Washington University. The VRI has designed and is implementing a hybrid electric/natural gas vehicle, Viking 32. I propose to build an electric automotive motor control system (EAMCS). This system will control the electric motor and drive train of Viking 32, see figure 1. The system will be designed to control the speed of the automobile by controlling the motor speed and shifting the two speed manual transmission to emulate the feel of an automatic transmission. This prototype system will be designed specifically for use in the VRI s Viking 32 hybrid vehicle. EAMCS Enclosure Drive Train EAMCS Electric Motor Figure 1. Electric Motor and Drive Train Representation - 1 -

3 DESCRIPTION The EAMCS will use a Motorola MC9S12DP256 microcontroller, via the Adapt9S12DP256B evaluation board, to control an electric motor and a modified two speed manual transmission, see figure 2. The complete system will integrate ten main components into the EAMCS; the microcontroller, throttle sensor, brake sensor, shifter position sensor, motor speed sensor, axle speed sensor, Unique Motions (UQM) inverter, UQM DC motor, a two speed manual transmission, and the DC servo amplifier. The motor speed and direction will be controlled using the data collected from the throttle, brake, and shifter position sensors. The gear selection of the transmission will be determined by the speed of the motor relative to the speed of the axles. The shifting times will be determined from the inputs of the motor speed sensor, throttle position sensor, and axle speed sensor. The shifter actuation will be performed using the DC Servo Amplifier that drives a DC brush type motor. Throttle Sensor Brake Sensor Shifter Position Sensor Adapt9S12DP256 Microcontroller CAN SAEJ1939 UQM INVERTER Motor Controller Motor Speed Sensor Axel Speed Sensor EAMCS DC Servo Amplifier Shift Controller UQM MOTOR AND TRANSMISSION ASSEMBLY Figure 2. Electric Automobile Motor Control System - 2 -

4 The EAMCS will be performing two major tasks for the vehicle, accelerating and decelerating. The acceleration of the car will be accomplished by sending requests to the UQM inverter to increase the speed of the motor while performing a gear shift, from first to second gear, at the appropriate time. The deceleration of the car will be accomplished by a request from the microcontroller, which slows down the motor by regenerating the motion of the car back into electrical energy. This regenerative action can be utilized in two ways. The first is to recharge the batteries, and the second is to be used as a brake, commonly referred to as regenerative braking. The 9S12 microcontroller will communicate to the UQM inverter via a controller area network (CAN) using the SAE J1939 communication standard. The UQM inverter receives command data from the microcontroller while sending back status data about itself and the UQM motor. The command data received from the microcontroller contains requested power, torque/speed, and CAN watchdog commands. The status messages sent out by the UQM inverter contain information about the UQM inverter and UQM motor s electric drive state, electric drive temperatures, and status of the CAN bus. BENEFITS The proposed Electric Automobile Motor Control System will enable Viking32 to be a competitive car for use in the annual Tour De Soul competition. By using the embedded system to control the motor speed and shifting times, the driver of the car will experience a ride much similar to that of a comparable production gasoline car, equipped with an automatic transmission. The use of regenerative - 3 -

5 braking will greatly improve the energy efficiency of the car as well as saving on the mechanical brake wear. COMPARISON The market for an embedded system to control the UQM motor/ inverter combination is very narrow. The Unique Mobility Company has engineering services that can be contracted out for specific applications, but has no advertised price on the rates they charge to build an automobile control system. Critical Specifications This project requires critical hardware for development. This system requires a UQM motor, UQM inverter, and the D.C. servo amplifier. The system also requires two separate power sources to operate, which are a 12 VDC power source and a 300VDC battery. The Adapt9S12DP256B microcontroller will require an aluminum enclosure to ensure protection from physical damage, heat, and noise. PROJECT DEVELOPMENT This project will be developed in both the electronics laboratory in room ET340 and also in the VRI spaces. While the Viking 32 vehicle is being constructed by the VRI team, the UQM inverter and motor will be setup in room ET340 for software development with the Introl-CodeWright integrated development environment and the Noral Debugger. After the car is assembled, the UQM inverter and motor will be mounted in the car for testing. At this point the software development will be continued by using a notebook computer with the Introl-CodeWright integrated development environment and the NOICE - 4 -

6 Debugger. The software for this project will be written in ANSI C using the MicroC/OS-II Preemptive Kernel. DEMONSTRATION The EAMCS will be demonstrated in the laboratory in room ET340. The demonstration will be performed using a static display of the aluminum enclosure with its lid removed to expose the Adapt9S12DP256 along with the accompanying hardware connections and the DC servo motor controller. In addition to the static display various development and action photos will be displayed