Electric Bicycles: A Guide to Design and Use (IEEE Press Series on Electronics Technology)

204 Pages·2005·14.66 MB·English

by  William C. Morchin

ELECTRIC BICYCLES
IEEE Press
445 Hoes Lane
Piscataway, NJ 08854
IEEE Press Editorial Board
Mohamed E. EI-Hawary, EditorinChief
M. Akay T. G.Croda M. S. Newman
J. B. Anderson R.J. Herrick F.M. B. Periera
R. J. Baker S. V.Kartalopoulos C. Singh
J. E. Brewer M. Montrose G. Zobrist
Kenneth Moore, DirectorofIEEEBook antiInformation Services(BIS)
Catherine Faduska, Senior AcquisitionEditor
ELECTRIC BICYCLES
A Guide to Design and Use
WILLIAM C. MORCHIN
HENRYOMAN
+IEEE
IEEEPRESS
ffiWILEY
~INTERSCIENCE
AJOHN WILEY& SONS, INC., PUBLICATION
Copyright © 2006 by The Institute of Electrical and Electronics Engineers, Inc.
All rights reserved.
Published by John Wiley & Sons, Inc., Hoboken, New Jersey.
Published simultaneously in Canada.
No partofthis publication may be reproduced, stored in a retrieval system, or transmitted in any
form or by any means,electronic, mechanical, photocopying, recording, scanning, or otherwise,
except as permitted under Section 107or 108ofthe 1976 United StatesCopyright Act, without
eitherthe prior written permission ofthe Publisher, or authorization through payment of the
appropriate per-copy feeto the CopyrightClearance Center, Inc., 222 Rosewood Drive, Danvers,
MA 01923, [phone], fax [phone], or on the web at www.copyright.com. Requests
to the Publisherfor permission should be addressed to the Permissions Department, John Wiley &
Sons, Inc., 111 RiverStreet, Hoboken, NJ07030, [phone], fax [phone], or online at
http://www.wiley.comlgo/permission.
Limitof LiabilitylDisclaimerof Warranty: While the publisher and authors have used their best
efforts in preparing this book, they make no representations or warranties with respect to the
accuracy or completeness of the contents ofthis book and specifically disclaim any implied
warranties ofmerchantability or fitness for a particular purpose. No warranty may be created or
extended by sales representatives or written sales materials. The advice and strategies contained
herein may not be suitable for your situation. You should consult with a professional where
appropriate. Neitherthe publisher nor authors shall be liable for any loss ofprofit or any other
commercial damages, inc1udingbut not limited to special, incidental, consequential, or other
damages.
Forgeneral information on our other products and services or for technical support, please contact
ourCustomerCare Department within the United States at [phone], outside the United
States at [phone] or fax [phone].
Wileyalsopublishes itsbooks ina variety of electronic formats. Somecontent that appears in print
may not be available inelectronic formats. For more information about Wiley products, visit our
web site at www.wiley.com.
Library 0/Congress Cataloging-in-Publication Data is available.
ISBN-I3978-0-471-67419-1
ISBN-IO0-471-67419-2 (acid-free paper)
10 9 8 7 6 54 3
CONTENTS
Preface xi
Electric Bicycles-History, Characteristics, and Uses 1
I.I Introduction
1.2 History of Bicycles 2
1.3 History of Electric Bicycles 3
1.4 Some Uses for the Electric-Powered Bicycle 6
1.4.1 Recreation 6
1.4.2 Commuting to Work 6
1.4.3 Delivery ofGoods and Services 7
1.4.4 Police and Army Applications 7
1.4.5 Opening Communication to Remote Areas 7
1.5 Examples of Electric Bicycles 7
1.5.1 Electric Scooters 17
1.6 Future ofElectric Bicycles 19
1.7 Laws and Regulations Goveming Electric Bicycles 20
1.8 Conclusion 21
References 22
2 Fundamentals 01Electric Propulsion 23
2.1 Introduction 23
2.2 Mathematical Model of Bicycle Performance: Power Required 23
2.2.1 Hill Climbing Power 23
2.2.2 Power to Overcome Wind Resistance 24
Coefficient ofDrag of Shapes ofInterest 25
Projected Area of the Bicycle Rider 25
2.2.3 Power to Overcome Rolling Resistance 26
2.2.4 Power for Acceleration 28
2.2.5 Measured Values 30
2.3 Estimating Required Motor Power 30
2.3.1 Determining Propulsion Power 30
2.3.2 Scaling Road Power to Find Required Motor Power 31
2.3.3 Motors Versus Human Muscles for Bicycle Propulsion 33
2.4 Selecting a Battery for Minimum Life-Cycle Cost 35
2.4.1 Battery Life-Cycle Cost 36
2.4.2 Battery Weight and Volume 37
2.5 Unique New Two-Wheeled Vehicles 38
2.5.1 Cheetah-A Superfast Bicycle 38
v
vi
CONTENTS
2.5.2 SegwayScooter 39
References 41
3 Sources 0/Electric Powerfor Bicycles 43
3.1 Introduction 43
3.1.1 Electric Bicycle Battery of 1895 44
3.2 Requirements of Batteries for Powering Electric Bicycles 45
3.2.1 Requirements 46
3.2.2 Battery Selection Uncertainties 46
3.2.3 Measured Energy Comparison in Electric Cars 47
3.3 Characteristics of Batteries Suitable for Electrlc Bicycle Propulsion 48
3.3.1 BatteryCandidates for Electric Bicycle Propulsion 48
ChargeControl of Long-Life Bicycle Batteries 50
Evaluating Energy Storage Alternatives for Bicycle Propulsion 50
Definitionsof Battery Types, Components, and Performance 51
3.3.2 Lead-Acid Battery-Its Limits for Electric Bicycle Propulsion 55
Lead-Acid Batteries: Uses and Performance Limits 56
Electrochemical Activity in Battery Charging and Discharging 57
Lead-Acid Battery Improvements and Limits 59
Adapting Lead- Acid Batteries to Electric Vehicle Propulsion 59
3.3.3 Nickel-Cadmium Batteries 60
Nickel-Cadmium Battery Design 60
Nickel-Cadmium Performance at Low Temperatures 61
Charge-Discharge Cycle Life of a Nickel-Cadmium Battery 61
Reliabilityof Nickel-Cadmium Batteries 62
Nickel Battery Cost 63
3.3.4 Gas Metal and Other Spacecraft Batteries 63
RedoxFlow Battery Stores Energy in Liquids 63
3.3.5 Lithium Ion Batteries Deliver Long Life with Low Weight in
Electric Bicycle Propulsion 64
AlternativeConfigurations of Lithium Ion Batteries 64
LithiumIon Battery Tested in Propelling an Electric Bicycle 65
Testinga Lithium Ion ModPack-Powered Electric Bicycle 67
Estimating Lithium Cell Capacity After 35,000
Charge-Discharge Cycles 67
Futureof Lithium Ion Batteries 68
LightweightLithium Ion Cells in Aluminum Case 69
3.3.6 Zinc, Sodium, and Other Zinc Batteries 70
SodiumSulfur Batteries for 100percent Coulombic Efficiency 70
V.S. Department of Energy's Battery Development for Electric
andHybrid Vehicles 71
3.4 Fuel Cells for Powering Electric Bicycles 71
3.4.1 Fuel Cell Electric-Power-Producing Basics 72
3.4.2 Fuel Cell Performance 74
HighCost of Transporting and Delivering Hydrogen 74
3.4.3 Fuel Cell Power for Electric Bicycles 75
3.5 Best New Electric Power Sources
for Bicycle Propulsion 76
CONTENTS vii
3.5.1 Zinc- Air Fuel Cell Power for Electric Bicycles 76
Zinc-air Cell Electrochemistry 78
Gas-Zinc Battery 79
3.5.2 Lithium Batteries 80
3.5.3 Fuel Cell Power Plant Technology Can Be aPower Source for
Electric Vehicles 81
Cost ofFuel Cell Power Plants 81
3.6 Bicycle Propulsion Power Sources to Watch 81
References 82
4 Battery Charging 85
4.1 History ofBattery-Charging Technology 85
4.2 Basic Functions ofBattery Chargers 86
4.3 Battery Characteristics Pertinent in Charging 86
4.4 Lead-Acid Battery Charging 87
4.5 Charger Design for Long Battery Life 89
4.6 Smart Chargers for New Nickel-Cadmium, Nickel-Metal Hydride, and
Lithium Batteries 89
4.6.1 Problems to Overcome 90
4.6.2 Charging Solutions for Nickel-Cadmium and Nickel-Metal
Hydride Batteries 92
Charging by Means of VoltageDetection 93
Charging by Means of Temperature Control 95
Charging by Means of Charge and Discharge Pulses 96
4.6.3 Charging Solutions for Lithium Batteries 97
Two-Step Charging 97
Three-Step Charging 98
Charging with Pulses and Rest Periods 99
4.7 Smart Batteries for Smart Chargers 100
4.8 Self-Discharge Rate of Nickel and Lithium Cells 102
4.8.1 Applicability of Commercial Fuel Gauges to Electric Bicycles 103
4.9 Recoverable Energy 103
4.10 Solar Panel Battery Chargers 106
References 107
5 Motors and Motor Controllers 109
5.1 Fundamental Principles of Electric Motors 110
5.1.1 Brush-and-Commutator Motor 112
5.1.2 Induction Motors 113
5.1.3 Efficient Permanent Magnet Synchronous Motors 115
5.2 Motor Characteristics for Electric Bicycle Propulsion 118
5.2.1 Torque-Speed Characteristics 118
5.2.2 Motor Output Power 119
5.3 Gear Ratio Determination 122
5.3.1 Mathematical Method for Determining Gear Ratio 122
viii
CONTENTS
5.3.2 Graphical Method for Determining Gear Ratio 123
5.3.3 Using Nameplate Data for Determination ofGear Ratio 126
5.4 Motor Control 127
5.4.1 Brush Motor Control 127
5.4.2 Brushless Motor Control 130
Single-Phase Brushless Motor Control 131
Multiphase Brushless Motor Control 132
Simulation Tools 134
5.4.3 Pedal Torque Used to Control Motor Power 134
References 137
6 The System Design 139
6.1 Introduction 139
6.2 Setting up the Electric Bicycle Systems Design 1.
6.2.1 System Design Project Functions 1.
6.2.2 System Design Cycle 141
Inputs 141
Process 142
Output 144
6.2.3 Importance of Preserving Data During Design Process 144
6.2.4 User-Pertinent Data in System Design Reviews 144
6.2.5 Uses of Systems Engineering Procedure to Evaluate
New Opportunities 145
6.3 Some Examples of Bicycle-SystemTrades 145
6.3.1 Trading System Weightwith Efficiency 145
6.3.2 Comparison of Specific Efficiencies of Electric Vehicles 146
6.3.3 Travel Speed Selection 147
6.3.4 Applying Battery Ragone Plots 147
6.3.5 Using Ultracapacitors to Reduce Battery Size 148
6.4 System Design Example 149
6.4.1 CustomerRequirements 149
6.4.2 Interpret, Prioritize, Identify, and Assign Weighting 150
6.4.3 Define System Requirements 150
6.4.4 Develop System Design 151
Motor Selection Trade Studies 151
Battery Selection Trade Studies 153
6.4.5 Develop Hardware and Software
Requirements Specification 154
Motor Specifications 154
Battery Specifications 157
6.4.6 Develop Detail Design Verification Plans 158
Motor Design VerificationPlan 158
Battery VerificationPlan 158
6.4.7 Subsystem Testing 159
6.4.8 System Integration and Testing 159
6.4.9 System Field Demonstration 160
References 160
ix
CONTENTS
7 Measurement 0/Performance 161
7.1 Measuring Propulsion Power to Detennine Propulsion Efficiency 161
7.1.1 Sources ofError 162
7.1.2 Finding Coefficient of Drag 163
7.2 Measuring Motor Efficiency Includes Measurement ofMotor Power 164
7.2.1 MotorOutput Power and Efficiency 164
7.2.2 Motor Speed Sensing 165
7.2.3 MotorInput Power 166
7.3 Measuring Battery Characteristics 167
7.3.1 Data Gathering 167
Strip Chart Recorders 167
Digital Data 168
References 170
8 Developments to Watch 171
8.1 Bicycle Systems 172
8.1.1 Frame Design, Clothing, and Energy Management 172
Molded Carbon-Fiber-Reinforced Bicycle Frames 172
Comfortable Rain-Resistant Cold-WeatherClothing 172
Energy Management of Power Sources 173
8.1.2 Bicycle Transportation Systems 173
World's Population Growth 173
Private and Public Partnerships 173
City Transportation Systems 174
Highway and Freeway Travel 175
Coming Events: Discoveries in Scientific Research 175
8.2 Energy Sources 175
8.2.1 Batteries 175
Large-Cell Lithium Batteries 175
Nickel-Metal Hydride Batteries 176
Zinc- Air Batteries 176
Other Batteries 176
8.2.2 Fuel Cells 177
Zinc-AirFuel Cell-A Development to Watch 177
8.2.3 Ultracapacitors and Fuel Cells to Replace Batteries 177
8.3 Solar Charging Systems 177
8.3.1 Storing SolarEnergy in Zinc-A Development to Watch 177
8.3.2 Thennovoltaic Cells 178
8.3.3 Integration ofFlexible Solar Cells with Batteries 178
8.4 High-Efficiency Motors 179
8.5 Controllers 179
References 180
Appendix: Table 0/Conversion Factorsfor Units 0/Measure 181
Index 187