Electric and Hybrid Vehicles Design Fundamentals SECOND EDITION Iqbal Husain CRC Press is an imprint of the Taylor & Francis Group, an informa business
2.6.1.1 Contents Preface Acknowledgments Author xv xix xxi 1. Introduction to Alternative Vehicles 1 1.1 Electric Vehicles 3 1.2 Hybrid Electric Vehicles 4 1.3 Electric and Hybrid Vehicle Components 5 1.4 Vehicle Mass and Performance 9 1.5 Electric Motor and Engine Ratings 10 1.6 Electric and Hybrid Vehicle History 12 1.6.1 The Early Years 12 1.6.2 1960s 14 1.6.3 1970s 14 1.6.4 1980s and 1990s 15 1.6.5 Recent EVs and HEVs 17 1.7 Well-to-Wheel Analysis 19 1.8 EV/ICEV Comparison 22 1.8.1 Efficiency Comparison 22 1.8.2 Pollution Comparison 24 1.8.3 Capital and Operating Cost Comparison 25 1.8.4 U.S. Dependence on Foreign Oil 25 1.9 Electric Vehicle Market 26 References 27 Assignment 28 2. Vehicle Mechanics 29 2.1 Roadway Fundamentals 30 2.2 Laws of Motion 32 2.3 Vehicle Kinetics 34 2.4 Dynamics 2.5 Propulsion 2.5.1 Force-Velocity of Vehicle Motion 37 Power 38 Characteristics 38 2.5.2 Maximum Gradability 40 2.6 Velocity and Acceleration 41 2.6.1 Constant FTR, Level Road 41 Velocity Profile 42 2.6.1.2 Distance Traversed 43 2.6.1.3 Tractive Power 44 2.6.1.4 Energy Required 44 2.6.2 Nonconstant FTR, General Acceleration 46 v
vi Contents 2.7 Tire-Road Force Mechanics 49 2.7.1 Slip 50 2.7.2 Traction Force at Tire-Road Interface 51 2.7.3 Force Transmission at Tire-Road Interface 52 2.7.4 Quarter-Car Model 53 2.7.5 Traction Limit and Control 55 2.8 Propulsion System Design 57 Problems 58 References 61 3. Alternative Vehicle Architectures 63 3.1 Electric Vehicles 63 3.2 Hybrid Electric Vehicles 65 3.2.1 Hybrids Based on Architecture 66 3.2.1.1 Series and Parallel Architectures 66 3.2.1.2 Series-Parallel Architecture 69 3.2.1.3 Series-Parallel 2x2 Architecture 70 3.2.2 Hybrids Based on Transmission Assembly 71 3.2.3 Hybrids Based on Degree of Hybridization 73 3.3 Plug-In Hybrid Electric Vehicle 73 3.4 Powertrain Component Sizing 75 3.4.1 EV Powertrain Sizing 76 3.4.1.1 Initial Acceleration 78 3.4.1.2 Rated Vehicle Velocity 79 3.4.1.3 Maximum Velocity 80 3.4.1.4 Maximum Gradability 80 3.4.2 HEV Powertrain Sizing 80 3.4.2.1 Rated Vehicle Velocity 82 3.4.2.2 Initial Acceleration 83 3.4.2.3 Maximum Velocity 84 3.4.2.4 Maximum Gradability 84 3.4.3 HEV Powertrain Sizing Example 84 3.4.3.1 Total Power Required: Initial Acceleration 85 3.4.3.2 IC Engine Power: Cruising Speed 88 3.4.3.3 Maximum Velocity 89 3.4.3.4 Generator Sizing 89 3.4.3.5 Battery Sizing 89 3.5 Mass Analysis and Packaging 90 3.6 Vehicle Simulation 92 3.6.1 Simulation Model 92 3.6.2 Standard Drive Cycles 93 Problems 97 References 98
Contents vii 4 Battery Energy Storage 99 4.1 Batteries in Electric and Hybrid Vehicles 101 4.2 Battery Basics 104 4.2.1 Battery Cell Structure 104 4.2.2 Chemical Reactions 105 4.3 Battery Parameters 110 4.3.1 Battery Capacity 110 4.3.2 Open Circuit Voltage Ill 4.3.3 Terminal Voltage 112 4.3.4 Practical Capacity 112 4.3.5 Discharge Rate 113 4.3.6 State of Charge 114 4.3.7 State of Discharge 115 4.3.8 Depth of Discharge 115 4.3.9 Battery Energy 116 4.3.10 Specific Energy 116 4.3.11 Battery Power 117 Power 118 4.3.12 Specific 4.3.13 Ragone Plots 118 4.4 Electrochemical Cell Fundamentals 119 4.4.1 Thermodynamic Voltage 120 4.4.2 Electrolysis and Faradaic Current 124 4.4.3 Electrode Kinetics 125 4.4.4 Mass Transport 128 4.4.5 Electrical Double Layer 130 4.4.6 Ohmic Resistance 131 4.4.7 Concentration Polarization 131 4.5 Battery Modeling 132 4.5.1 Electric Circuit Models 133 4.5.1.1 Basic Battery Model 134 4.5.1.2 Run-Time Battery Model 137 4.5.1.3 Impedance-Based 4.5.1.4 First Principle Model 138 Model 139 4.5.2 Empirical Models 140 4.5.2.1 Range Prediction with Constant Current 142 Discharge 4.5.2.2 Range Prediction with Power Density Approach 146 4.6 Traction Batteries 148 4.6.1 Lead-Acid Battery 149 4.6.2 Nickel-Cadmium Battery 150 4.6.3 Nickel-Metal-Hydride Battery 151 4.6.4 Li-Ion Battery 152 4.6.5 Li-Polymer Battery 154
viii Contents 4.6.6 Zinc-Air Battery 154 4.6.7 Sodium-Sulfur Battery 155 4.6.8 Sodium-Metal-Chloride Battery 155 4.6.9 Goals for Advanced Batteries 157 4.7 Battery Pack Management 159 4.7.1 Battery Management System 159 4.7.2 SoC Measurement 161 4.7.3 Battery Cell Balancing 162 4.7.4 Battery Charging 164 Problems 165 References 168 5. Alternative Energy Storage 171 5.1 Fuel Cells 172 5.1.1 Fuel Cell Characteristics 173 5.1.2 Fuel Cell Types 175 5.1.2.1 Alkaline Fuel Cell 175 5.1.2.2 Proton Exchange Membrane Fuel Cell 175 5.1.2.3 Direct Methanol Fuel Cell 175 5.1.2.4 Phosphoric Acid Fuel Cell 176 5.1.2.5 Molten Carbonate Fuel Cell 176 5.1.2.6 Solid Oxide Fuel Cell 176 5.1.3 Fuel Cell Model 178 5.1.4 Hydrogen Storage Systems 179 5.1.5 Reformers 180 5.1.6 Fuel Cell Electric Vehicle 181 5.2 Ultracapacitors 183 5.2.1 Symmetrical Ultracapacitors 184 5.2.2 Asymmetrical Ultracapacitors 186 5.2.3 Ultracapacitor Modeling 187 5.3 Compressed Air Storage 189 5.4 Flywheels 191 Problems 193 References 194 6. Electric Machines 197 6.1 Simple Electric Machines 198 6.1.1 Fundamental Machine Phenomena 199 6.1.1.1 Motional Voltage 199 6.1.1.2 Electromagnetic Force 200 6.1.2 DC Simple Machine 200 6.1.2.1 Induced Voltage 201 6.1.2.2 Force and Torque 203 6.1.2.3 DC Machine Back-EMF and Torque 204
Contents ix 6.1.3 Simple Reluctance Machine 206 6.2 DC Machines 207 6.3 Three-Phase AC Machines 213 6.3.1 Sinusoidal Stator Windings 213 6.3.2 Number of Poles 215 6.3.3 Three-Phase Sinusoidal Windings 216 6.3.4 Space Vector Representation 216 6.3.4.1 Interpretation of Space Vectors 221 6.3.4.2 Inverse Relations 221 6.3.4.3 Resultant mmf in a Balanced System 222 6.3.4.4 Mutual Inductance L, and Induced Stator Voltage 224 6.3.5 Types of AC Machines 225 6.4 Induction Machines 226 6.4.1 Per-Phase Equivalent Circuit 227 6.4.2 Simplified Torque Expression 230 6.4.3 Speed Control Methods 233 6.4.4 Regenerative Braking 235 6.5 Permanent Magnet Machines 237 6.5.1 Permanent Magnets 238 6.5.1.1 Ferrites 238 6.5.1.2 Samarium Cobalt 239 6.5.1.3 Neodymium-Iron-Boron 239 6.5.2 PM Synchronous Motors 240 6.5.3 PMSM Models 242 6.5.3.1 Voltage Equations 243 6.5.3.2 Per-Phase Equivalent Circuit 244 6.5.4 PM Brushless DC Motors 246 6.5.4.1 PM BLDC Machine Modeling 246 6.6 Switched Reluctance Machines 249 6.6.1 Advantages and Disadvantages 250 6.6.2 SRM Design/Basics 251 6.6.3 Principle of Operation 253 6.6.3.1 Voltage-Balance Equation 253 6.6.3.2 Energy Conversion 254 6.6.3.3 Torque Production 256 Characteristics 257 6.6.3.4 Torque-Speed Problems 259 References 260 7. Power Electronic Converters 261 7.1 Power Electronic Switches 262 7.1.1 Diode 263 7.1.2 Power BJT 264 7.1.3 Power MOSFET 266
X Contents 7.1A IGBT 266 7.1.5 Bidirectional Switch 266 7.2 DC/DC Converters 267 7.2.1 Non-Isolated DC/DC Converters 268 7.2.1.1 Buck Converter 268 7.2.1.2 Boost Converter 269 7.2.1.3 Buck-Boost Converter 271 7.2.1.4 Fourth-Order DC/DC Converters 272 7.2.1.5 Powertrain Boost Converter 272 7.2.2 Isolated DC/DC Converters 273 7.3 Cell Balancing Converters 278 7.3.1 Passive Balancing Methods 279 7.3.2 Active Balancing Methods 281 7.3.2.1 Individual DC/DC Converter 282 7.3.2.2 Centralized DC/DC Converter 283 7.3.2.3 Current Diverter DC /DC Converter 285 References 286 8. Electric Motor Drives 287 8.1 Electric Drive Components 287 8.2 DC Drives 289 8.2.1 Two-Quadrant Chopper 289 8.2.2 Open Loop Drive 291 8.2.2.1 Steady-State Analysis of Quadrant 1 293 8.2.2.2 Ripple Reduction in i 295 8.2.2.3 Acceleration (CCM) 296 8.2.2.4 Acceleration (DCM) 297 8.2.2.5 Acceleration (Uncontrollable Mode) 298 8.2.2.6 Braking Operation (CCM in Steady State) 299 8.2.2.7 Regenerative Power 302 8.3 Operating Point Analysis 303 8.4 AC Drives 308 8.4.1 Six-Step Operation 309 8.4.1.1 Harmonic Analysis 312 8.4.2 Pulse Width Modulation 313 8.4.2.1 Sinusoidal PWM 314 8.4.2.2 Harmonics in Sinusoidal PWM 316 8.4.2.3 Space Vector PWM 316 8.4.2.4 Generation of SV PWM Switching Signals 319 8.4.3 Current Control Methods 322 8.4.3.1 Hysteresis Current Controller 323 8.4.3.2 Ramp Comparison Controller 324 8.5 SRM Drives 325 8.5.1 SRM Converters 325 8.5.2 SRM Controls 327
Contents xi 8.5.2.1 Control Parameters 327 8.5.2.2 Advance Angle Calculation 328 8.5.2.3 Voltage-Controlled Drive 329 8.5.2.4 Current-Controlled Drive 330 8.5.2.5 Advanced Control Strategies 330 Problems 331 References 335 9. Control of AC Machines 337 9.1 Vector Control of AC Motors 338 9.2 cfy Modeling 340 9.2.1 Rotating Reference Frame 343 9.2.2 Induction Machine dq Model 344 9.2.3 Power and Electromagnetic Torque 346 9.3 Induction Machine Vector Control 348 9.3.1 Rotor Flux-Oriented Vector Control 349 9.3.2 Direct and Indirect Vector Control 352 9.3.2.1 Direct Vector Control 352 9.3.2.2 Indirect Vector Control 354 9.3.2.3 Vector Control Implementation 354 9.4 PM Machine Vector Control 355 9.4.1 Voltage and Torque in Reference Frame 355 9.4.2 Simulation Model 356 9.4.3 Transformation Equations 358 9.4.4 PM Synchronous Motor Drives 358 9.4.4.1 Flux Weakening 360 9.4.4.2 Current and Voltage Controllers 360 Problems 361 References 362 10. Internal Combustion Engines 363 10.1 Internal Combustion Engines 363 10.1.1 Reciprocating Engines 365 10.1.2 Practical and Air-Standard Cycles 367 10.1.2.1 Air-Standard Otto Cycle 368 10.1.2.2 Air-Standard Diesel Cycle 370 10.1.3 Gas Turbine Engines 371 10.2 BMEP and BSFC 373 10.3 Vehicle Fuel Economy 375 10.3.1 Fuel Economy in Hybrids 378 10.4 Emission Control System 379 10.4.1 Generation of Pollutants 380 10.4.2 Effect of Air-Fuel Ratio on Emissions 382 10.4.3 NOT Flow Rate 384 10.4.4 Emission Control Components 388
xii Contents 10.4.4.1 Exhaust Gas Recirculation 388 10.4.4.2 Catalytic Converter 388 10.4.5 Treatment of Diesel Exhaust Emissions 389 10.4.5.1 Diesel Oxidation Catalysts 390 10.4.5.2 Diesel Particulate Filters 390 10.4.5.3 Methods of NO, Reduction 391 Problem 393 References 393 11. Powertrain Components and Brakes 395 11.1 Powertrain Components 396 11.1.1 Electric Vehicle Powertrain 397 11.2 Gears 398 11.2.1 Gear Ratio 400 11.2.2 Torque-Speed Characteristics 403 11.2.3 Planetary Gear Set 406 11.3 Cratches 408 11.4 Differential 408 11.5 Transmission 409 11.5.1 Manual Transmission 410 11.5.2 Automatic Transmission 412 11.5.2.1 Torque Converter 412 11.5.2.2 Automatic Transmission in Hybrids 414 11.5.3 Continuously Variable Transmission 414 11.5.4 ecvt/hev Transmission 415 11.6 Vehicle Brakes 416 11.6.1 Conventional Brake System 416 11.6.2 Electromechanical Brake System 422 Problem 425 References 426 12. Cooling Systems 427 12.1 Climate Control System 427 12.1.1 Vapor-Compression Refrigeration Cycle 428 12.1.2 Vehicle Air-Conditioning System 431 12.2 Powertrain Component-Cooling System 433 References 437 13. Hybrid Vehicle Control Strategy 439 13.1 Vehicle Supervisory Controller 440 13.2 Mode Selection Strategy 441 13.2.1 Mechanical Power-Split Hybrid Modes 444 13.2.1.1 Electric Only (Low Speeds, Reverse, Battery Charging) 445 13.2.1.2 Engine Starting (Low Speeds) 446
Contents xiii 13.2.1.3 Parallel Mode (Heavy Acceleration) 446 13.2.1.4 Power-Split Mode (Cruise, Light Acceleration) 447 13.2.1.5 Engine-Brake Mode (Driver Selectable Mode) 448 13.2.1.6 Regeneration Mode (Vehicle Braking) 449 13.2.2 Series-Parallel 2x2 Hybrid Modes 449 13.2.2.1 Electric-Only (Low Speeds, Reverse, Battery Charging) 450 13.2.2.2 Series Mode (Low Speeds) 450 13.2.2.3 Power-Split Mode (Cruise, Light Acceleration) 450 13.2.2.4 Parallel Mode (Heavy Acceleration) 450 13.3 Modal Control Strategies 451 13.3.1 Series Control 452 13.3.2 Parallel Control 454 13.3.3 Series-Parallel Control 456 13.3.3.1 Mechanical Power-Split IC Engine Control 456 13.3.3.2 Series-Parallel 2x2 Control 458 13.3.4 Energy Storage System Control 460 13.3.5 Regeneration Control 461 Problems 465 References 466 14. Vehicle Communications 469 14.1 OSI Seven-Layer Model 469 14.2 In-Vehicle Communications 471 14.3 Controller Area Network 472 14.3.1 CAN Transfer Protocol 474 14.3.2 CAN Transfer Layer 475 14.3.2.1 Bit Timing 475 14.3.2.2 CAN Message Frames 476 14.3.2.3 Message Arbitration 479 14.3.2.4 Error Detection and Error Signaling 480 14.3.3 CAN Physical Layer 481 14.3.4 CAN Programming 483 References 486 Index 487