Empowers engineering professionals and students with the knowledge and skills required to engineer electric vehicle powertrain architectures, energy storage systems, power electronics converters and electric drives.
The modern electric powertrain is relatively new for the automotive industry, and engineers are challenged with designing affordable, efficient and high-performance electric powertrains as the industry undergoes a technological evolution. Co-authored by two electric vehicle (EV) engineers with decades of experience designing and putting into production all of the powertrain technologies presented, this book provides readers with the hands-on knowledge, skills and expertise they need to rise to that challenge.
This four-part practical guide provides a comprehensive review of battery, hybrid and fuel cell EV systems and the associated energy sources, power electronics, machines, and drives. The first part of the book begins with a historical overview of electromobility and the related environmental impacts motivating the development of the electric powertrain. Vehicular requirements for electromechanical propulsion are then presented. Battery electric vehicles (BEV), fuel cell electric vehicles (FCEV), and conventional and hybrid electric vehicles (HEV) are then described, contrasted and compared for vehicle propulsion. The second part of the book features in-depth analysis of the electric powertrain traction machines, with a particular focus on the induction machine and the surface- and interior-permanent magnet ac machines. The brushed dc machine is also considered due to its ease of operation and understanding, and its historical place, especially as the traction machine on NASA’s Mars rovers. The third part of the book features the theory and applications for the propulsion, charging, accessory, and auxiliary power electronics converters. Chapters are presented on isolated and non-isolated dc-dc converters, traction inverters, and battery charging. The fourth part presents the introductory and applied electromagnetism required as a foundation throughout the book.
- Introduces and holistically integrates the key EV powertrain technologies.
- Provides a comprehensive overview of existing and emerging automotive solutions.
- Provides experience-based expertise for vehicular and powertrain system and sub-system level study, design, and optimization.
- Presents many examples of powertrain technologies from leading manufacturers.
- Discusses the dc traction machines of the Mars rovers, the ultimate EVs from NASA.
- Investigates the environmental motivating factors and impacts of electromobility.
- Presents a structured university teaching stream from introductory undergraduate to postgraduate.
- Includes real-world problems and assignments of use to design engineers, researchers, and students alike.
- Features a companion website with numerous references, problems, solutions, and practical assignments.
- Includes introductory material throughout the book for the general scientific reader.
- Contains essential reading for government regulators and policy makers.
Electric Powertrain: Energy Systems, Power Electronics and Drives for Hybrid, Electric and Fuel Cell Vehicles is an important professional resource for practitioners and researchers in the battery, hybrid, and fuel cell EV transportation industry. The book is a structured holistic textbook for the teaching of the fundamental theories and applications of energy sources, power electronics, and electric machines and drives to engineering undergraduate and postgraduate students.
Textbook Structure and Suggested Teaching Curriculum
This is primarily an engineering textbook covering the automotive powertrain, energy storage and energy conversion, power electronics, and electrical machines. A significant additional focus is placed on the engineering design, the energy for transportation, and the related environmental impacts. This textbook is an educational tool for practicing engineers and others, such as transportation policy planners and regulators. The modern automobile is used as the vehicle upon which to base the theory and applications, which makes the book a useful educational reference for our industry colleagues, from chemists to engineers. This material is also written to be of interest to the general reader, who may have little or no interest in the power electronics and machines. Introductory science, mathematics, and an inquiring mind suffice for some chapters. The general reader can read the introduction to each of the chapters and move to the next as soon as the material gets too advanced for him or her.
Part I Vehicles and Energy Sources
Chapter 1 Electromobility and the Environment
Chapter 2 Vehicle Dynamics
Chapter 3 Batteries
Chapter 4 Fuel Cells
Chapter 5 Conventional and Hybrid Powertrains
Part II Electrical Machines
Chapter 6 Introduction to Traction Machines
Chapter 7 The Brushed DC Machine
Chapter 8 Induction Machines
Chapter 9 Surface-permanent-magnet AC Machines
Chapter 10: Interior-permanent-magnet AC Machines
Part III Power Electronics
Chapter 11 DC-DC Converters
Chapter 12 Isolated DC-DC Converters
Chapter 13 Traction Drives and Three-phase Inverters
Chapter 14 Battery Charging
Chapter 15 Control of the Electric Drive
Part IV Basics
Chapter 16 Introduction to Electromagnetism, Ferromagnetism, and Electromechanical Energy Conversion
The first third of the book (Chapters 1 to 6), plus parts of Chapters 14 and 16, can be taught to the general science or engineering student in the second or third year. It covers the introductory automotive material using basic concepts from mechanical, electrical, environmental, and electrochemical engineering. Chapter 14 on electrical charging and Chapter 16 on electromagnetism can also be used as a general introduction to electrical engineering.
The basics of electromagnetism, ferromagnetism and electromechanical energy conversion (Chapter 16) and dc machines (Chapter 7) can be taught to second year (sophomore) engineering students who have completed introductory electrical circuits and physics.
The third year (junior) students typically have covered ac circuit analysis, and so they can cover ac machines, such as the induction machine (Chapter 8) and the surface permanent-magnet ac machine (Chapter 9). As the students typically have studied control theory, they can investigate the control of the speed and torque loops of the motor drive (Chapter 15). Power electronics, featuring non-isolated buck and boost converters (Chapter 11), can also be introduced in the third year.
The final-year (senior) students can then go on to cover the more advanced technologies of the interior-permanent-magnet ac machine (Chapter 10). Isolated power converters (Chapter 12), such as the full-bridge and resonant converters, inverters (Chapter 13), and power-factor-corrected battery chargers (Chapter 14), are covered in the power electronics section. This material can also be covered at the introductory postgraduate level. Various homework, simulation, and research exercises are presented throughout the textbook.
The reader is encouraged to attempt these exercises as part of the learning experience.
Table of Contents
Preface xix
Acknowledgments xxi
Textbook Structure and Suggested Teaching Curriculum xxii
About the Companion Web Site xxiv
Part 1 Vehicles and Energy Sources 1
1 Electromobility and the Environment 3
1.1 A Brief History of the Electric Powertrain 4
1.1.1 Part I – The Birth of the Electric Car 4
1.1.2 Part II – The Resurgent Electric Powertrain 5
1.1.3 Part III – Success at Last for the Electric Powertrain 6
1.2 Energy Sources for Propulsion and Emissions 10
1.2.1 Carbon Emissions from Fuels 12
1.2.2 Greenhouse Gases and Pollutants 13
1.3 The Advent of Regulations 15
1.3.1 Regulatory Considerations and Emissions Trends 17
1.3.2 Heavy-Duty Vehicle Regulations 18
1.4 Drive Cycles 19
1.4.1 EPA Drive Cycles 19
1.5 BEV Fuel Consumption, Range, and mpge 24
1.6 Carbon Emissions for Conventional and Electric Powertrains 25
1.6.1 Well-to-Wheel and Cradle-to-Grave Emissions 27
1.6.2 Emissions due to the Electrical Grid 28
1.7 An Overview of Conventional, Battery, Hybrid, and Fuel Cell Electric Systems 29
1.7.1 Conventional IC Engine Vehicle 30
1.7.2 BEVs 30
1.7.3 HEVs 31
1.7.4 FCEV 33
1.7.5 A Comparison by Efficiency of Conventional, Hybrid, Battery, and Fuel Cell Vehicles 34
1.7.6 A Case Study Comparison of Conventional, Hybrid, Battery, and Fuel Cell Vehicles 35
1.8 A Comparison of Automotive and Other Transportation Technologies 36
References 37
Further Reading 38
Problems 38
Assignments 39
2 Vehicle Dynamics 40
2.1 Vehicle Load Forces 40
2.1.1 Basic Power, Energy, and Speed Relationships 41
2.1.2 Aerodynamic Drag 42
2.1.3 Rolling Resistance 45
2.1.4 Vehicle Road-Load Coefficients from EPA Coast-Down Testing 46
2.1.5 Battery Electric Vehicle Range at Constant Speed 49
2.1.6 Gradability 51
2.2 Vehicle Acceleration 52
2.2.1 Regenerative Braking of the Vehicle 54
2.2.2 Traction Motor Characteristics 54
2.2.3 Acceleration of the Vehicle 57
2.3 Simple Drive Cycle for Vehicle Comparisons 60
References 62
Further Reading 62
Problems 62
Sample MATLAB Code 63
Assignment: Modeling of a BEV 66
3 Batteries 68
3.1 Introduction to Batteries 68
3.1.1 Batteries Types and Battery Packs 68
3.1.2 Basic Battery Operation 73
3.1.3 Basic Electrochemistry 74
3.1.4 Units of Battery Energy Storage 76
3.1.5 Capacity Rate 77
3.1.6 Battery Parameters and Comparisons 79
3.2 Lifetime and Sizing Considerations 81
3.2.1 Examples of Battery Sizing 84
3.2.2 Battery Pack Discharge Curves and Aging 86
3.3 Battery Charging, Protection, and Management Systems 88
3.3.1 Battery Charging 88
3.3.2 Battery Failure and Protection 88
3.3.3 Battery Management System 89
3.4 Battery Models 90
3.4.1 A Simple Novel Curve Fit Model for BEV Batteries 92
3.4.2 Voltage, Current, Resistance, and Efficiency of Battery Pack 95
3.4.3 A Simple Curve-Fit Model for HEV Batteries 96
3.4.4 Charging 97
3.4.5 Determining the Cell/Pack Voltage for a Given Output\Input Power 99
3.4.6 Cell Energy and Discharge Rate 100
3.5 Example: The Fuel Economy of a BEV Vehicle with a Fixed Gear Ratio 102
References 105
Further Reading 106
Problems 106
Appendix: A Simplified Curve-Fit Model for BEV Batteries 108
4 Fuel Cells 111
4.1 Introduction to Fuel Cells 111
4.1.1 Fuel Cell Vehicle Emissions and Upstream Emissions 113
4.1.2 Hydrogen Safety Factors 113
4.2 Basic Operation 114
4.2.1 Fuel Cell Model and Cell Voltage 116
4.2.2 Power and Efficiency of Fuel Cell and Fuel Cell Power Plant System 118
4.2.3 Fuel Cell Characteristic Curves 119
4.3 Sizing the Fuel Cell Plant 120
4.3.1 Example: Sizing a Fuel Cell 121
4.3.2 Toyota Mirai 121
4.3.3 Balance of Plant 121
4.3.4 Boost DC-DC Converter 122
4.4 Fuel Cell Aging 122
4.5 Example: Sizing Fuel Cell System for Heavy Goods Tractor–Trailer Combination 124
4.6 Example: Fuel Economy of Fuel Cell Electric Vehicle 125
References 129
Problems 129
Assignments 130
5 Conventional and Hybrid Powertrains 131
5.1 Introduction to HEVs 131
5.2 Brake Specific Fuel Consumption 134
5.2.1 Example: Energy Consumption, Power Output, Efficiency, and BSFC 135
5.3 Comparative Examples of Conventional, Series, and Series-Parallel Hybrid Systems 138
5.3.1 Example: Fuel Economy of IC Engine Vehicle with Gasoline or Diesel Engine 138
5.3.2 Example: Fuel Economy of Series HEV 144
5.3.3 Example: Fuel Economy of Series-Parallel HEV 146
5.3.4 Summary of Comparisons 148
5.4 The Planetary Gears as a Power-Split Device 148
5.4.1 Powertrain of 2004 Toyota Prius 150
5.4.2 Example: CVT Operating in Electric Drive Mode (Vehicle Launch and Low Speeds) 151
5.4.3 Example: CVT Operating in Full-Power Mode 153
5.4.4 Example: CVT Operating in Cruising and Generating Mode 154
References 155
Problems 155
Assignments 156
Part 2 Electrical Machines 159
6 Introduction to Traction Machines 161
6.1 Propulsion Machine Overview 161
6.1.1 DC Machines 162
6.1.2 AC Machines 163
6.1.3 Comparison of Traction Machines 167
6.1.4 Case Study – Mars Rover Traction Motor 169
6.2 Machine Specifications 170
6.2.1 Four-Quadrant Operation 170
6.2.2 Rated Parameters 171
6.2.3 Rated Torque 172
6.2.4 Rated and Base Speeds 172
6.2.5 Rated Power 172
6.2.6 Peak Operation 173
6.2.7 Starting Torque 173
6.3 Characteristic Curves of a Machine 173
6.3.1 Constant-Torque Mode 173
6.3.2 Constant-Power Mode 174
6.3.3 Maximum-Speed Mode 174
6.3.4 Efficiency Maps 174
6.4 Conversion Factors of Machine Units 176
References 177
7 The Brushed DC Machine 178
7.1 DC Machine Structure 178
7.2 DC Machine Electrical Equivalent Circuit 180
7.3 DC Machine Circuit Equations 182
7.3.1 No-Load Spinning Loss 183
7.3.2 No-Load Speed 184
7.3.3 Maximum Power 184
7.3.4 Rated Conditions 184
7.4 Power, Losses, and Efficiency in the PM DC Machine 185
7.5 Machine Control using Power Electronics 186
7.5.1 Example: Motoring using a PM DC Machine 186
7.6 Machine Operating as a Motor or Generator in Forward or Reverse Modes 189
7.6.1 Example: Generating/Braking using a PM DC Machine 190
7.6.2 Example: Motoring in Reverse 191
7.7 Saturation and Armature Reaction 191
7.7.1 Example: Motoring using PM DC Machine and Machine Saturation 192
7.8 Using PM DC Machine for EV Powertrain 193
7.8.1 Example: Maximum Speeds using PM DC Machine 194
7.9 Using WF DC Machine for EV Powertrain 195
7.9.1 Example: Motoring using WF DC Machine 197
7.10 Case Study – Mars Rover Traction Machine 199
7.11 Thermal Characteristics of Machine 201
7.11.1 Example of Steady-State Temperature Rise 202
7.11.2 Transient Temperature Rise 203
7.11.3 Example of Transient Temperature Rise 203
References 204
Problems 204
8 Induction Machines 206
8.1 Stator Windings and the Spinning Magnetic Field 207
8.1.1 Stator Magnetic Flux Density 209
8.1.2 Space-Vector Current and the Rotating Magnetic Field 211
8.2 Induction Machine Rotor Voltage, Current, and Torque 216
8.2.1 Rotor Construction 216
8.2.2 Induction Machine Theory of Operation 216
8.3 Machine Model and Steady-State Operation 219
8.3.1 Power in Three-Phase Induction Machine 222
8.3.2 Torque in Three-Phase Induction Machine 223
8.3.3 Phasor Analysis of Induction Motor 225
8.3.4 Machine Operation When Supplied by Current Source 225
8.4 Variable-Speed Operation of Induction Machine 234
8.4.1 Constant Volts per hertz Operation 235
8.4.2 Variable-Speed Operation 235
8.5 Machine Test 240
8.5.1 DC Resistance Test 240
8.5.2 Locked-Rotor Test 240
8.5.3 No-Load Test 242
References 244
Further Reading 244
Problems 245
Sample MATLAB Code 246
9 Surface-Permanent-Magnet AC Machines 249
9.1 Basic Operation of SPM Machines 249
9.1.1 Back EMF of a Single Coil 249
9.1.2 Back EMF of Single Phase 250
9.1.3 SPM Machine Equations 253
9.2 Per-Phase Analysis of SPM Machine 255
9.2.1 Per-Phase Equivalent Circuit Model for SPM Machine 256
9.2.2 Phasor Analysis of SPM Machine 257
9.2.3 Machine Saturation 263
9.2.4 SPM Torque–Speed Characteristics 264
9.2.5 High-Speed Operation of SPM Machine above Rated Speed 266
9.2.6 Machine Characteristics for Field-Weakened Operation 270
References 272
Further Reading 273
Problems 273
MATLAB Code 274
10 Interior-Permanent-Magnet AC Machine 276
10.1 Machine Structure and Torque Equations 276
10.2 d- and q-Axis Inductances 278
10.2.1 Example: Estimating the d-axis and q-axis Inductances for 2004 Toyota Prius Motor 281
10.3 IPM Machine Test 281
10.3.1 No-Load Spin Test 282
10.3.2 DC Torque Test 282
10.4 Basic Theory and Low-Speed Operation 286
10.4.1 Example: Motoring at Rated Condition 287
10.4.2 Maximum Torque per Ampere (MTPA) 289
10.4.3 Maximum Torque per Volt (MTPV) or Maximum Torque per Flux (MTPF) 289
10.5 High-Speed Operation of IPM Machine 289
10.5.1 Example: Motoring at High Speed using IPM Machine 289
10.6 dq Modeling of Machines 291
10.6.1 Constant Current Transformation 292
10.6.2 Constant Power Transformation 294
References 295
Further Reading 295
Problems 296
Assignments 298
Part 3 Power Electronics 299
11 DC-DC Converters 301
11.1 Introduction 301
11.2 Power Conversion – Common and Basic Principles 304
11.2.1 The Basic Topologies 306
11.2.2 The Half-Bridge Buck-Boost Bidirectional Converter 307
11.3 The Buck or Step-Down Converter 307
11.3.1 Analysis of Voltage Gain of Buck Converter in CCM 309
11.3.2 BCM Operation of Buck Converter 317
11.3.3 DCM Operation of Buck Converter 319
11.4 The Boost or Step-up Converter 325
11.4.1 Analysis of Voltage Gain of Boost Converter in CCM 326
11.4.2 BCM Operation of Boost Converter 330
11.4.3 DCM Operation of Boost Converter 332
11.5 Power Semiconductors 336
11.5.1 Power Semiconductor Power Loss 337
11.5.2 Total Semiconductor Power Loss and Junction Temperature 341
11.6 Passive Components for Power Converters 342
11.6.1 Example: Inductor Sizing 342
11.6.2 Capacitor Sizing 343
11.7 Interleaving 343
11.7.1 Example: Two-Phase Interleaved Boost Converter 345
References 346
Further Reading 346
Problems 346
Assignments 349
Appendix I 349
Appendix II: Buck-Boost Converter 349
Appendix III: Silicon Carbide Converters and Inverters 352
12 Isolated DC-DC Converters 353
12.1 Introduction 353
12.1.1 Advantages of Isolated Power Converters 353
12.1.2 Power Converter Families 354
12.2 The Forward Converter 355
12.2.1 CCM Currents in Forward Converter 357
12.2.2 CCM Voltages in Forward Converter 362
12.2.3 Sizing the Transformer 365
12.3 The Full-Bridge Converter 365
12.3.1 Operation of Hard-Switched Full-Bridge Converter 367
12.3.2 CCM Currents in Full-Bridge Converter 370
12.3.3 CCM Voltages in the Full-Bridge Converter 376
12.4 Resonant Power Conversion 377
12.4.1 LCLC Series-Parallel Resonant Converter 377
12.4.2 Desirable Converter Characteristics for Inductive Charging 378
12.4.3 Fundamental-Mode Analysis and Current-Source Operation 381
12.4.4 Simulation 385
References 388
Further Reading 388
Problems 388
Assignments 390
Appendix I: RMS and Average Values of Ramp and Step Waveforms 390
Appendix II: Flyback Converter 391
13 Traction Drives and Three-Phase Inverters 392
13.1 Three-Phase Inverters 392
13.2 Modulation Schemes 393
13.2.1 Sinusoidal Modulation 395
13.2.2 Sinusoidal Modulation with Third Harmonic Addition 396
13.2.3 Overmodulation and Square Wave 398
13.3 Sinusoidal Modulation 398
13.3.1 Modulation Index m 399
13.3.2 Inverter Currents 401
13.3.3 Switch, Diode, and Input Average Currents 401
13.3.4 Switch, Diode, DC Link, and Input Capacitor RMS Currents 403
13.3.5 Example: Inverter Currents 404
13.4 Inverter Power Loss 405
13.4.1 Conduction Loss of IGBT and Diode 405
13.4.2 Switching Loss of IGBT Module 405
13.4.3 Total Semiconductor Power Loss and Junction Temperature 407
13.4.4 Example: Regenerative Currents 408
References 409
Further Reading 409
Problems 410
Assignments 411
14 Battery Charging 412
14.1 Basic Requirements for Charging System 412
14.2 Charger Architectures 414
14.3 Grid Voltages, Frequencies, and Wiring 416
14.4 Charger Functions 418
14.4.1 Real Power, Apparent Power, and Power Factor 419
14.5 Charging Standards and Technologies 422
14.5.1 SAE J1772 422
14.5.2 VDE-AR-E 2623-2-2 425
14.5.3 CHAdeMo 425
14.5.4 Tesla 425
14.5.5 Wireless Charging 425
14.6 The Boost Converter for Power Factor Correction 427
14.6.1 The Boost PFC Power Stage 428
14.6.2 Sizing the Boost Inductor 430
14.6.3 Average Currents in the Rectifier 431
14.6.4 Switch and Diode Average Currents 432
14.6.5 Switch, Diode, and Capacitor RMS Currents 434
14.6.6 Power Semiconductors for Charging 434
References 438
Further Reading 438
Problems 439
Assignments 440
15 Control of the Electric Drive 441
15.1 Introduction to Control 441
15.1.1 Feedback Controller Design Approach 442
15.2 Modeling the Electromechanical System 443
15.2.1 The Mechanical System 443
15.2.2 The PM DC Machine 446
15.2.3 The DC-DC Power Converter 447
15.2.4 The PI Controller 447
15.3 Designing Torque Loop Compensation 448
15.3.1 Example: Determining Compensator Gain Coefficients for Torque Loop 449
15.4 Designing Speed Control Loop Compensation 449
15.4.1 Example: Determining Compensator Gain Coefficients for Speed Loop 451
15.5 Acceleration of Battery Electric Vehicle (BEV) using PM DC Machine 451
15.6 Acceleration of BEV using WF DC Machine 452
References 455
Problems 455
Assignment and Sample MATLAB Codes 456
Part 4 Electromagnetism 459
16 Introduction to Electromagnetism, Ferromagnetism, and Electromechanical Energy Conversion 461
16.1 Electromagnetism 462
16.1.1 Maxwell’s Equations 462
16.2 Ferromagnetism 467
16.2.1 Magnetism and Hysteresis 467
16.2.2 Hard and Soft Ferromagnetic Materials 470
16.3 Self-Inductance 473
16.3.1 Basic Inductor Operation 474
16.3.2 Inductor Equations 475
16.3.3 Reluctance 478
16.3.4 Energy Stored in Magnetic Field 481
16.3.5 Core Loss 482
16.3.6 Copper Loss 484
16.3.7 Inductor Sizing using Area Product 487
16.3.8 High-Frequency Operation and Skin Depth 488
16.4 Hard Ferromagnetic Materials and Permanent Magnets 489
16.4.1 Example: Remanent Flux Density 490
16.4.2 Example: The Recoil Line 492
16.4.3 Example: Air Gap Flux Density due to a Permanent Magnet 494
16.4.4 Maximum Energy Product 494
16.4.5 Force due to Permanent Magnet 494
16.4.6 Electromagnet 497
16.5 The Transformer 498
16.5.1 Theory of Operation 498
16.5.2 Transformer Equivalent Circuit 500
16.5.3 Transformer Voltages and Currents 501
16.5.4 Sizing the Transformer using the Area-Product (AP) Method 505
16.6 The Capacitor 506
16.6.1 Sizing Polypropylene High-Voltage Capacitor 508
16.7 Electromechanical Energy Conversion 509
16.7.1 Ampere’s Force Law 509
16.7.2 General Expression for Torque on Current-Carrying Coil 510
16.7.3 Torque, Flux Linkage, and Current 511
16.7.4 Faraday’s Law of Electromagnetic Induction 512
16.7.5 Lenz’s Law and Fleming’s Right Hand Rule 512
References 513
Further Reading 514
Further Viewing 515
Problems 515
Assignments 518
Reference Conversion Table 519
Index 521
