Electric Powertrain

John G. Hayes, PhD, MSEE, MBA, lectures at University College Cork, Ireland, and specialises in automotive, industrial and renewable energy systems and related power electronics, machines and electromagnetism. He previously worked in Southern California for ten years at General Motors' Hughes Aircraft subsidiary developing EV propulsion and inductive charging systems for the General Motors EV1, the first modern production EV. John's recent focus has been on the development of integrated and holistic EV teaching materials for the engineering student and the automotive professional. G. Abas Goodarzi, PhD, P.E., is the Chief Executive Officer and President of US Hybrid Corporation, Torrance, California, which he founded in 1999. He is also the President of US FuelCell, a company formed with the acquisition by US Hybrid of the United Technologies PEM fuel cell transportation division. He served as Senior Scientist at General Motors' Hughes Aircraft subsidiary, and as Technical Director for the General Motors EV1. He has designed various EV, HEV, and FCEV powertrain systems for light, medium, and heavy-duty, on-road, off-road, and special-purpose vehicles.

• Preface xixAcknowledgments xxiTextbook Structure and Suggested Teaching Curriculum xxiiAbout the Companion Web Site xxivPart 1 Vehicles and Energy Sources 11 Electromobility and the Environment 31.1 A Brief History of the Electric Powertrain 41.1.1 Part I – The Birth of the Electric Car 41.1.2 Part II – The Resurgent Electric Powertrain 51.1.3 Part III – Success at Last for the Electric Powertrain 61.2 Energy Sources for Propulsion and Emissions 101.2.1 Carbon Emissions from Fuels 121.2.2 Greenhouse Gases and Pollutants 131.3 The Advent of Regulations 151.3.1 Regulatory Considerations and Emissions Trends 171.3.2 Heavy-Duty Vehicle Regulations 181.4 Drive Cycles 191.4.1 EPA Drive Cycles 191.5 BEV Fuel Consumption, Range, and mpge 241.6 Carbon Emissions for Conventional and Electric Powertrains 251.6.1 Well-to-Wheel and Cradle-to-Grave Emissions 271.6.2 Emissions due to the Electrical Grid 281.7 An Overview of Conventional, Battery, Hybrid, and Fuel Cell Electric Systems 291.7.1 Conventional IC Engine Vehicle 301.7.2 BEVs 301.7.3 HEVs 311.7.4 FCEV 331.7.5 A Comparison by Efficiency of Conventional, Hybrid, Battery, and Fuel Cell Vehicles 341.7.6 A Case Study Comparison of Conventional, Hybrid, Battery, and Fuel Cell Vehicles 351.8 A Comparison of Automotive and Other Transportation Technologies 36References 37Further Reading 38Problems 38Assignments 392 Vehicle Dynamics 402.1 Vehicle Load Forces 402.1.1 Basic Power, Energy, and Speed Relationships 412.1.2 Aerodynamic Drag 422.1.3 Rolling Resistance 452.1.4 Vehicle Road-Load Coefficients from EPA Coast-Down Testing 462.1.5 Battery Electric Vehicle Range at Constant Speed 492.1.6 Gradability 512.2 Vehicle Acceleration 522.2.1 Regenerative Braking of the Vehicle 542.2.2 Traction Motor Characteristics 542.2.3 Acceleration of the Vehicle 572.3 Simple Drive Cycle for Vehicle Comparisons 60References 62Further Reading 62Problems 62Sample MATLAB Code 63Assignment: Modeling of a BEV 663 Batteries 683.1 Introduction to Batteries 683.1.1 Batteries Types and Battery Packs 683.1.2 Basic Battery Operation 733.1.3 Basic Electrochemistry 743.1.4 Units of Battery Energy Storage 763.1.5 Capacity Rate 773.1.6 Battery Parameters and Comparisons 793.2 Lifetime and Sizing Considerations 813.2.1 Examples of Battery Sizing 843.2.2 Battery Pack Discharge Curves and Aging 863.3 Battery Charging, Protection, and Management Systems 883.3.1 Battery Charging 883.3.2 Battery Failure and Protection 883.3.3 Battery Management System 893.4 Battery Models 903.4.1 A Simple Novel Curve Fit Model for BEV Batteries 923.4.2 Voltage, Current, Resistance, and Efficiency of Battery Pack 953.4.3 A Simple Curve-Fit Model for HEV Batteries 963.4.4 Charging 973.4.5 Determining the Cell/Pack Voltage for a Given Output\Input Power 993.4.6 Cell Energy and Discharge Rate 1003.5 Example: The Fuel Economy of a BEV Vehicle with a Fixed Gear Ratio 102References 105Further Reading 106Problems 106Appendix: A Simplified Curve-Fit Model for BEV Batteries 1084 Fuel Cells 1114.1 Introduction to Fuel Cells 1114.1.1 Fuel Cell Vehicle Emissions and Upstream Emissions 1134.1.2 Hydrogen Safety Factors 1134.2 Basic Operation 1144.2.1 Fuel Cell Model and Cell Voltage 1164.2.2 Power and Efficiency of Fuel Cell and Fuel Cell Power Plant System 1184.2.3 Fuel Cell Characteristic Curves 1194.3 Sizing the Fuel Cell Plant 1204.3.1 Example: Sizing a Fuel Cell 1214.3.2 Toyota Mirai 1214.3.3 Balance of Plant 1214.3.4 Boost DC-DC Converter 1224.4 Fuel Cell Aging 1224.5 Example: Sizing Fuel Cell System for Heavy Goods Tractor–Trailer Combination 1244.6 Example: Fuel Economy of Fuel Cell Electric Vehicle 125References 129Problems 129Assignments 1305 Conventional and Hybrid Powertrains 1315.1 Introduction to HEVs 1315.2 Brake Specific Fuel Consumption 1345.2.1 Example: Energy Consumption, Power Output, Efficiency, and BSFC 1355.3 Comparative Examples of Conventional, Series, and Series-Parallel Hybrid Systems 1385.3.1 Example: Fuel Economy of IC Engine Vehicle with Gasoline or Diesel Engine 1385.3.2 Example: Fuel Economy of Series HEV 1445.3.3 Example: Fuel Economy of Series-Parallel HEV 1465.3.4 Summary of Comparisons 1485.4 The Planetary Gears as a Power-Split Device 1485.4.1 Powertrain of 2004 Toyota Prius 1505.4.2 Example: CVT Operating in Electric Drive Mode (Vehicle Launch and Low Speeds) 1515.4.3 Example: CVT Operating in Full-Power Mode 1535.4.4 Example: CVT Operating in Cruising and Generating Mode 154References 155Problems 155Assignments 156Part 2 Electrical Machines 1596 Introduction to Traction Machines 1616.1 Propulsion Machine Overview 1616.1.1 DC Machines 1626.1.2 AC Machines 1636.1.3 Comparison of Traction Machines 1676.1.4 Case Study – Mars Rover Traction Motor 1696.2 Machine Specifications 1706.2.1 Four-Quadrant Operation 1706.2.2 Rated Parameters 1716.2.3 Rated Torque 1726.2.4 Rated and Base Speeds 1726.2.5 Rated Power 1726.2.6 Peak Operation 1736.2.7 Starting Torque 1736.3 Characteristic Curves of a Machine 1736.3.1 Constant-Torque Mode 1736.3.2 Constant-Power Mode 1746.3.3 Maximum-Speed Mode 1746.3.4 Efficiency Maps 1746.4 Conversion Factors of Machine Units 176References 1777 The Brushed DC Machine 1787.1 DC Machine Structure 1787.2 DC Machine Electrical Equivalent Circuit 1807.3 DC Machine Circuit Equations 1827.3.1 No-Load Spinning Loss 1837.3.2 No-Load Speed 1847.3.3 Maximum Power 1847.3.4 Rated Conditions 1847.4 Power, Losses, and Efficiency in the PM DC Machine 1857.5 Machine Control using Power Electronics 1867.5.1 Example: Motoring using a PM DC Machine 1867.6 Machine Operating as a Motor or Generator in Forward or Reverse Modes 1897.6.1 Example: Generating/Braking using a PM DC Machine 1907.6.2 Example: Motoring in Reverse 1917.7 Saturation and Armature Reaction 1917.7.1 Example: Motoring using PM DC Machine and Machine Saturation 1927.8 Using PM DC Machine for EV Powertrain 1937.8.1 Example: Maximum Speeds using PM DC Machine 1947.9 Using WF DC Machine for EV Powertrain 1957.9.1 Example: Motoring using WF DC Machine 1977.10 Case Study – Mars Rover Traction Machine 1997.11 Thermal Characteristics of Machine 2017.11.1 Example of Steady-State Temperature Rise 2027.11.2 Transient Temperature Rise 2037.11.3 Example of Transient Temperature Rise 203References 204Problems 2048 Induction Machines 2068.1 Stator Windings and the Spinning Magnetic Field 2078.1.1 Stator Magnetic Flux Density 2098.1.2 Space-Vector Current and the Rotating Magnetic Field 2118.2 Induction Machine Rotor Voltage, Current, and Torque 2168.2.1 Rotor Construction 2168.2.2 Induction Machine Theory of Operation 2168.3 Machine Model and Steady-State Operation 2198.3.1 Power in Three-Phase Induction Machine 2228.3.2 Torque in Three-Phase Induction Machine 2238.3.3 Phasor Analysis of Induction Motor 2258.3.4 Machine Operation When Supplied by Current Source 2258.4 Variable-Speed Operation of Induction Machine 2348.4.1 Constant Volts per hertz Operation 2358.4.2 Variable-Speed Operation 2358.5 Machine Test 2408.5.1 DC Resistance Test 2408.5.2 Locked-Rotor Test 2408.5.3 No-Load Test 242References 244Further Reading 244Problems 245Sample MATLAB Code 2469 Surface-Permanent-Magnet AC Machines 2499.1 Basic Operation of SPM Machines 2499.1.1 Back EMF of a Single Coil 2499.1.2 Back EMF of Single Phase 2509.1.3 SPM Machine Equations 2539.2 Per-Phase Analysis of SPM Machine 2559.2.1 Per-Phase Equivalent Circuit Model for SPM Machine 2569.2.2 Phasor Analysis of SPM Machine 2579.2.3 Machine Saturation 2639.2.4 SPM Torque–Speed Characteristics 2649.2.5 High-Speed Operation of SPM Machine above Rated Speed 2669.2.6 Machine Characteristics for Field-Weakened Operation 270References 272Further Reading 273Problems 273MATLAB Code 27410 Interior-Permanent-Magnet AC Machine 27610.1 Machine Structure and Torque Equations 27610.2 d- and q-Axis Inductances 27810.2.1 Example: Estimating the d-axis and q-axis Inductances for 2004 Toyota Prius Motor 28110.3 IPM Machine Test 28110.3.1 No-Load Spin Test 28210.3.2 DC Torque Test 28210.4 Basic Theory and Low-Speed Operation 28610.4.1 Example: Motoring at Rated Condition 28710.4.2 Maximum Torque per Ampere (MTPA) 28910.4.3 Maximum Torque per Volt (MTPV) or Maximum Torque per Flux (MTPF) 28910.5 High-Speed Operation of IPM Machine 28910.5.1 Example: Motoring at High Speed using IPM Machine 28910.6 dq Modeling of Machines 29110.6.1 Constant Current Transformation 29210.6.2 Constant Power Transformation 294References 295Further Reading 295Problems 296Assignments 298Part 3 Power Electronics 29911 DC-DC Converters 30111.1 Introduction 30111.2 Power Conversion – Common and Basic Principles 30411.2.1 The Basic Topologies 30611.2.2 The Half-Bridge Buck-Boost Bidirectional Converter 30711.3 The Buck or Step-Down Converter 30711.3.1 Analysis of Voltage Gain of Buck Converter in CCM 30911.3.2 BCM Operation of Buck Converter 31711.3.3 DCM Operation of Buck Converter 31911.4 The Boost or Step-up Converter 32511.4.1 Analysis of Voltage Gain of Boost Converter in CCM 32611.4.2 BCM Operation of Boost Converter 33011.4.3 DCM Operation of Boost Converter 33211.5 Power Semiconductors 33611.5.1 Power Semiconductor Power Loss 33711.5.2 Total Semiconductor Power Loss and Junction Temperature 34111.6 Passive Components for Power Converters 34211.6.1 Example: Inductor Sizing 34211.6.2 Capacitor Sizing 34311.7 Interleaving 34311.7.1 Example: Two-Phase Interleaved Boost Converter 345References 346Further Reading 346Problems 346Assignments 349Appendix I 349Appendix II: Buck-Boost Converter 349Appendix III: Silicon Carbide Converters and Inverters 35212 Isolated DC-DC Converters 35312.1 Introduction 35312.1.1 Advantages of Isolated Power Converters 35312.1.2 Power Converter Families 35412.2 The Forward Converter 35512.2.1 CCM Currents in Forward Converter 35712.2.2 CCM Voltages in Forward Converter 36212.2.3 Sizing the Transformer 36512.3 The Full-Bridge Converter 36512.3.1 Operation of Hard-Switched Full-Bridge Converter 36712.3.2 CCM Currents in Full-Bridge Converter 37012.3.3 CCM Voltages in the Full-Bridge Converter 37612.4 Resonant Power Conversion 37712.4.1 LCLC Series-Parallel Resonant Converter 37712.4.2 Desirable Converter Characteristics for Inductive Charging 37812.4.3 Fundamental-Mode Analysis and Current-Source Operation 38112.4.4 Simulation 385References 388Further Reading 388Problems 388Assignments 390Appendix I: RMS and Average Values of Ramp and Step Waveforms 390Appendix II: Flyback Converter 39113 Traction Drives and Three-Phase Inverters 39213.1 Three-Phase Inverters 39213.2 Modulation Schemes 39313.2.1 Sinusoidal Modulation 39513.2.2 Sinusoidal Modulation with Third Harmonic Addition 39613.2.3 Overmodulation and Square Wave 39813.3 Sinusoidal Modulation 39813.3.1 Modulation Index m 39913.3.2 Inverter Currents 40113.3.3 Switch, Diode, and Input Average Currents 40113.3.4 Switch, Diode, DC Link, and Input Capacitor RMS Currents 40313.3.5 Example: Inverter Currents 40413.4 Inverter Power Loss 40513.4.1 Conduction Loss of IGBT and Diode 40513.4.2 Switching Loss of IGBT Module 40513.4.3 Total Semiconductor Power Loss and Junction Temperature 40713.4.4 Example: Regenerative Currents 408References 409Further Reading 409Problems 410Assignments 41114 Battery Charging 41214.1 Basic Requirements for Charging System 41214.2 Charger Architectures 41414.3 Grid Voltages, Frequencies, and Wiring 41614.4 Charger Functions 41814.4.1 Real Power, Apparent Power, and Power Factor 41914.5 Charging Standards and Technologies 42214.5.1 SAE J1772 42214.5.2 VDE-AR-E 2623-2-2 42514.5.3 CHAdeMo 42514.5.4 Tesla 42514.5.5 Wireless Charging 42514.6 The Boost Converter for Power Factor Correction 42714.6.1 The Boost PFC Power Stage 42814.6.2 Sizing the Boost Inductor 43014.6.3 Average Currents in the Rectifier 43114.6.4 Switch and Diode Average Currents 43214.6.5 Switch, Diode, and Capacitor RMS Currents 43414.6.6 Power Semiconductors for Charging 434References 438Further Reading 438Problems 439Assignments 44015 Control of the Electric Drive 44115.1 Introduction to Control 44115.1.1 Feedback Controller Design Approach 44215.2 Modeling the Electromechanical System 44315.2.1 The Mechanical System 44315.2.2 The PM DC Machine 44615.2.3 The DC-DC Power Converter 44715.2.4 The PI Controller 44715.3 Designing Torque Loop Compensation 44815.3.1 Example: Determining Compensator Gain Coefficients for Torque Loop 44915.4 Designing Speed Control Loop Compensation 44915.4.1 Example: Determining Compensator Gain Coefficients for Speed Loop 45115.5 Acceleration of Battery Electric Vehicle (BEV) using PM DC Machine 45115.6 Acceleration of BEV using WF DC Machine 452References 455Problems 455Assignment and Sample MATLAB Codes 456Part 4 Electromagnetism 45916 Introduction to Electromagnetism, Ferromagnetism, and Electromechanical Energy Conversion 46116.1 Electromagnetism 46216.1.1 Maxwell’s Equations 46216.2 Ferromagnetism 46716.2.1 Magnetism and Hysteresis 46716.2.2 Hard and Soft Ferromagnetic Materials 47016.3 Self-Inductance 47316.3.1 Basic Inductor Operation 47416.3.2 Inductor Equations 47516.3.3 Reluctance 47816.3.4 Energy Stored in Magnetic Field 48116.3.5 Core Loss 48216.3.6 Copper Loss 48416.3.7 Inductor Sizing using Area Product 48716.3.8 High-Frequency Operation and Skin Depth 48816.4 Hard Ferromagnetic Materials and Permanent Magnets 48916.4.1 Example: Remanent Flux Density 49016.4.2 Example: The Recoil Line 49216.4.3 Example: Air Gap Flux Density due to a Permanent Magnet 49416.4.4 Maximum Energy Product 49416.4.5 Force due to Permanent Magnet 49416.4.6 Electromagnet 49716.5 The Transformer 49816.5.1 Theory of Operation 49816.5.2 Transformer Equivalent Circuit 50016.5.3 Transformer Voltages and Currents 50116.5.4 Sizing the Transformer using the Area-Product (AP) Method 50516.6 The Capacitor 50616.6.1 Sizing Polypropylene High-Voltage Capacitor 50816.7 Electromechanical Energy Conversion 50916.7.1 Ampere’s Force Law 50916.7.2 General Expression for Torque on Current-Carrying Coil 51016.7.3 Torque, Flux Linkage, and Current 51116.7.4 Faraday’s Law of Electromagnetic Induction 51216.7.5 Lenz’s Law and Fleming’s Right Hand Rule 512References 513Further Reading 514Further Viewing 515Problems 515Assignments 518Reference Conversion Table 519Index 521

Hayes and Goodarzi have focused their considerable talent and experience to teaching the inner workings of the electric car. Readers, whether engineers, students, or the interested public will find this book a treasure trove of knowledge on modern automotive technology. In conclusion, what a great book! —John M Miller, J-N-J Miller Design Services PLLC, Longview, Texas, USA I highly recommend 'Electric Powertrain: Energy Systems, Power Electronics and Drives for Hybrid, Electric and Fuel Cell Vehicles' by Dr John G. Hayes and Dr G. Abas Goodarzi. I use this book as my core teaching text on my module Transportation Power and Systems 3, which I teach to third year BEng and MEng Mechanical Engineering undergraduates in Queen's University Belfast. This book captures the fundamentals and in-depth aspects of the key elements of the course I teach including drive cycles, power trains for hybrids, vehicle dynamics, batteries and machines. The worked examples are excellent. The text book is very well laid out with superb well thought-out practical problems at the end of each chapter. This book is very relevant to those who wish to expand their knowledge of hybrid vehicles. It seamlessly integrates the electrical, civil and mechanical disciplines in this growing and multidisciplinary area. This is especially important considering the sustainable direction of land-based transport will take over the next decade as we strive to combat global warming and reduce greenhouse gas emissions. —Dr Aoife Foley, School of Mechanical and Aerospace Engineering, Queen's University Belfast, United Kingdom