Date of Award

2016

Document Type

Open Access Master's Report

Degree Name

Master of Science in Electrical Engineering (MS)

Administrative Home Department

Department of Electrical and Computer Engineering

Advisor 1

Wayne Weaver

Committee Member 1

John Lukowski

Committee Member 2

Lucia Gauchia

Abstract

This project was conducted to analyze (model and simulate) and optimize an electric motor based drive system to propel a typical passenger vehicle in an urban driving environment. Although there are many HEV and EV type systems on the market today, this paper chose the Toyota Prius HEV system as a baseline using a brushless AC motor.

Although a vehicle can be driven many ways, a more standardized Urban Dynamometer Driving Schedule, UDDS, was chosen to simulate real driving conditions. This schedule is determined by the US Environmental Protection Agency, EPA, and is intended to represent the city driving conditions for a typical passenger vehicle in a city environment.

A high level modeling and simulation approach for vehicle and motor drive was taken to focus on motor operation and gear ratios from the electric to the mechanical drive system.

Vehicle battery being the limiting factor in the range of the HEV vehicle, the energy usage of the battery was optimized to ensure lowest energy dissipation, thus gaining the most mileage out of the vehicle.

How to maximize the drive mileage for a given battery size? There are multiple dynamic factors that affect the battery usage and efficiency. Factors such as road conditions, vehicle speed, weather, weight, and aerodynamics are amongst the many that govern battery mileage. Gear ratios and selection also play a crucial role in the loading and efficiency of the motor, thus affecting the battery mileage.

In this project, the gear ratios between the electric motor and the vehicle drive shaft were the focus for this optimization. As part of the overall system model, gears and gear ratios were modeled and simulated to determine their optimum ratios for finding the minimum energy usage point for the battery.

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