MUEV Phase III

By: Kevin Jaris & Nathan Golick

Introduction

• Petroleum is a finite resource.

• Demand for clean energy is driving the increase in the production of electric cars.

• Improvements in regenerative braking techniques will increase the range and efficiency of electric cars.

Regenerative Braking

• Cars generally dissipate kinetic energy via friction braking.

• Regenerative braking recovers a significant amount of the kinetic energy.

• Energy returned to battery.

• Increases range per charge.

Past Work Phase I

• Design a prototype electric vehicle test platform for testing with the following specifications:– Minimum round trip distance of 25 miles– Maximum speed of 40 mph– Operate within temperature range of -10˚F to 100˚F– Acquire and display data from the motor and battery

subsystems– Operate within a curb weight of 800 to 1800 lbs

Past Work Phase II

Modeling • Battery • DC Motor • Controller • Vehicle Dynamics • Loads

– A/C – Lighting – Heat

Verify and Optimize Vehicle Model • Perform data acquisition • Adjust model until desired performance is achieved. • Compare experimental and simulated outputs of

subsystems

Original Project Goals

• Design and simulate power electronics

• Build power electronics

• Test power electronics in lab

• Connect to DC motor/generator

• Create braking profile

• Model in Simulink

• Investigate variable speed drive

Functional Description

• The DC motor/generator produces a back EMF voltage during regenerative braking.

• Back EMF voltage is the input to the boost converter.

• The boost converter output is 43 volts.

• Output voltage charges batteries.

Performance Specifications

• Generate a constant 43 volt output voltage while in regenerative braking mode

• Braking voltages range from about 5 to 35 volts.

• System designed for minimal project construction costs.

System Block Diagram

DC MotorDrive Shaft Coupling

DC Motor/Generator

Current Limited Control

Boost Converter/

Power Electronics

Brake Input

Battery

Field Current Control

Electronics

Boost Converter Basics

Design Process

• Calculate the component values

• Design and simulate the boost converter

• Build boost converter

• Analyzed and compared the results

• Solve problems that arose

Design Equations

2)1(2

)(DD

Io

VoTsL

Vofs

DIoC

)1(

1

DVin

Vo

Vo

PIo motor

Boost Converter Schematic

Low Voltage Input Boost Converter Simulation

Vin

High Voltage Input Boost Converter Simulation

Test Setup

Additional Circuitry

• Safety shut off circuit

• Gate driver circuit

• Snubber circuit

Issues

• MOSFET temperature

• Power supply current limit

• Wire gauge

• IC chips highly vulnerable to static discharge

• Individual to series inductor switch

Output Voltage

Input Current and Drain Voltage

Solutions

• Parallel MOSFETs• Parallel inductors• Thermocouple to monitor temperature• Fan and heat sinks for heat dissipation to

keep case temperature under 90º C• Moved to power lab• Replaced wire with 16 gauge• Testing and replacement of ICs

Final Results

Vin(V) Duty Cycle Vo(V) Io(A)

35 20% 45.5 4.2

32.5 21% 43.2 5.2

30 29% 43.5 5.2

27.5 35% 43.3 5.2

25 42% 43.3 5.2

22.5 50% 43.3 5.2

20 62% 43.6 5.2

17.5 70% 43.5 5.2

Accomplished Goals

• Designed and simulated boost converter/power electronics

• Built power electronics

• Tested power electronics

Future Work

• Complete duty cycle controller

• Attach DC motor/generator

• Test with braking profile

• Model subsystem in Simulink

• Connect regenerative braking system to the MUEV

Questions?

Power Dissipation