Hybrid Electric Vehicle System Modeling and Control

Dr. Wei (Kevin) Liu is an Engineering Specialist in the Electric Power & Advanced Systems Department of General Motors with expertise in dynamic system design, performance analysis, modeling and control. He has 14 years of hybrid electric vehicle engineering experience and 15 years of academic experience. Dr. Liu's primary technical interests are dynamic system control, modeling, performance analysis and fault diagnosis. He currently focuses on the energy management strategy, energy storage system modeling and control algorithm development of hybrid vehicle systems at General Motors. He has authored over 30 technical papers and holds eight patents.

Preface xiv

List of Abbreviations xviii

Nomenclature xxii

1 Introduction 1

1.1 Classification of Hybrid Electric Vehicles 2

1.1.1 Micro Hybrid Electric Vehicles 2

1.1.2 Mild Hybrid Electric Vehicles 2

1.1.3 Full Hybrid Electric Vehicles 3

1.1.4 Electric Vehicles 3

1.1.5 Plug-in Hybrid Electric Vehicles 4

1.2 General Architectures of Hybrid Electric Vehicles 4

1.2.1 Series Hybrid 4

1.2.2 Parallel Hybrid 5

1.2.3 Series–Parallel Hybrid 6

1.3 Typical Layouts of the Parallel Hybrid Electric Propulsion System 7

1.4 Hybrid Electric Vehicle System Components 8

1.5 Hybrid Electric Vehicle System Analysis 10

1.5.1 Power Flow of Hybrid Electric Vehicles 10

1.5.2 Fuel Economy Benefits of Hybrid Electric Vehicles 11

1.5.3 Typical Drive Cycles 11

1.5.4 Vehicle Drivability 11

1.5.5 Hybrid Electric Vehicle Fuel Economy and Emissions 13

1.6 Controls of Hybrid Electric Vehicles 13

References 14

2 Basic Components of Hybrid Electric Vehicles 15

2.1 The Prime Mover 15

2.1.1 Gasoline Engines 15

2.1.2 Diesel Engines 17

2.1.3 Fuel Cells 17

2.2 Electric Motor with a DC–DC Converter and a DC–AC Inverter 20

2.3 Energy Storage System 21

2.3.1 Energy Storage System Requirements for Hybrid Electric Vehicles 21

2.3.2 Basic Types of Battery for Hybrid Electric Vehicle System Applications 25

2.3.3 Ultracapacitors for Hybrid Electric Vehicle System Applications 34

2.4 Transmission System in Hybrid Electric Vehicles 35

References 37

3 Hybrid Electric Vehicle System Modeling 38

3.1 Modeling of an Internal Combustion Engine 38

3.1.1 Cranking (Key Start) 39

3.1.2 Engine Off 41

3.1.3 Idle 41

3.1.4 Engine On 41

3.1.5 Engine Fuel Economy and Emissions 44

3.2 Modeling of an Electric Motor 48

3.2.1 Operation in the Propulsion Mode 48

3.2.2 Operation in the Regenerative Mode 49

3.2.3 Operation in Spinning Mode 49

3.3 Modeling of the Battery System 53

3.3.1 Modeling Electrical Behavior 54

3.3.2 SOC Calculation 56

3.3.3 Modeling Thermal Behavior 56

3.4 Modeling of the Transmission System 59

3.4.1 Modeling of the Clutch and Power Split Device 60

3.4.2 Modeling of the Torque Converter 67

3.4.3 Modeling of the Gearbox 69

3.4.4 Modeling of the Transmission Controller 70

3.5 Modeling of a Multi-mode Electrically Variable Transmission 73

3.5.1 Basics of One-mode ECVT 73

3.5.2 Basics of Two-mode ECVT 78

3.6 Lever Analogy as a Tool for ECVT Kinematic Analysis 85

3.6.1 Lever System Diagram Set-up 85

3.6.2 Lever Analogy Diagram for ECVT Kinematic Analysis 87

3.7 Modeling of the Vehicle Body 91

3.8 Modeling of the Final Drive and Wheel 92

3.8.1 Final Drive Model 92

3.8.2 Wheel Model 92

3.9 PID-based Driver Model 94

3.9.1 Principle of PID Control 95

3.9.2 Driver Model 96

References 96

4 Power Electronics and Electric Motor Drives in Hybrid Electric Vehicles 97

4.1 Basic Power Electronic Devices 97

4.1.1 Diodes 98

4.1.2 Thyristors 99

4.1.3 Bipolar Junction Transistors (BJTs) 101

4.1.4 Metal Oxide Semiconductor Field Effect Transistors (MOSFETs) 103

4.1.5 Insulated Gate Bipolar Transistors (IGBTs) 105

4.2 DC–DC Converters 107

4.2.1 Basic Principle of a DC–DC Converter 107

4.2.2 Step-down (Buck) Converter 109

4.2.3 Step-up (Boost) Converter 117

4.2.4 Step-down/up (Buck-boost) Converter 121

4.2.5 DC–DC Converters Applied in Hybrid Electric Vehicle Systems 125

4.3 DC–AC Inverters 129

4.3.1 Basic Concepts of DC–AC Inverters 129

4.3.2 Single-phase DC–AC Inverters 134

4.3.3 Three-phase DC–AC Inverters 137

4.4 Electric Motor Drives 141

4.4.1 BLDC Motor and Control 141

4.4.2 AC Induction Motor and Control 152

4.5 Plug-in Battery Charger Design 162

4.5.1 Basic Configuration of a PHEV/BEV Battery Charger 162

4.5.2 Power Factor and Correcting Techniques 164

4.5.3 Controls of a Plug-in Charger 168

References 168

5 Energy Storage System Modeling and Control 169

5.1 Introduction 169

5.2 Methods of Determining the State of Charge 171

5.2.1 Current-based SOC Determination Method 172

5.2.2 Voltage-based SOC Determination Method 177

5.2.3 Extended Kalman-filter-based SOC Determination Method 183

5.2.4 SOC Determination Method Based on Transient Response Characteristics (TRCs) 186

5.2.5 Fuzzy-logic-based SOC Determination Method 189

5.2.6 Combination of SOCs Estimated Through Different Approaches 191

5.2.7 Further Discussion on SOC Calculations in Hybrid Electric Vehicle Applications 192

5.3 Estimation of Battery Power Availability 196

5.3.1 PNGV HPPC Power Availability Estimation Method 198

5.3.2 Revised PNGV HPPC Power Availability Estimation Method 199

5.3.3 Power Availability Estimation Based on the Electrical Circuit Equivalent Model 200

5.4 Battery Life Prediction 207

5.4.1 Aging Behavior and Mechanism 207

5.4.2 Definition of the State of Life 209

5.4.3 SOL Determination under Storage Conditions 210

5.4.4 SOL Determination under Cycling Conditions 214

5.4.5 Lithium Metal Plating Issue and Symptoms in Li-ion Batteries 223

5.5 Cell Balancing 224

5.5.1 SOC Balancing 224

5.5.2 Hardware Implementation of Balancing 224

5.5.3 Cell-balancing Control Algorithms and Evaluation 227

5.6 Estimation of Cell Core Temperature 236

5.6.1 Introduction 236

5.6.2 Core Temperature Estimation of an Air-cooled, Cylinder-type HEV Battery 237

5.7 Battery System Efficiency 241

References 242

6 Energy Management Strategies for Hybrid Electric Vehicles 243

6.1 Introduction 243

6.2 Rule-based Energy Management Strategy 244

6.3 Fuzzy-logic-based Energy Management Strategy 245

6.3.1 Fuzzy Logic Control 246

6.3.2 Fuzzy-logic-based HEV Energy Management Strategy 253

6.4 Determination of the Optimal ICE Operational Points of Hybrid Electric Vehicles 261

6.4.1 Mathematical Description of the Problem 261

6.4.2 Procedures of Optimal Operational Point Determination 263

6.4.3 Golden Section Searching Method 264

6.4.4 Finding the Optimal Operational Points 265

6.4.5 Example of the Optimal Determination 265

6.4.6 Performance Evaluation 269

6.5 Cost-function-based Optimal Energy Management Strategy 278

6.5.1 Mathematical Description of Cost-function-based Optimal Energy Management 279

6.5.2 An Example of Optimization Implementation 282

6.6 Optimal Energy Management Strategy Incorporated with Cycle Pattern Recognition 282

6.6.1 Driving Cycle/Style Pattern Recognition Algorithm 282

6.6.2 Determination of the Optimal Energy Distribution 285

References 287

7 Other Hybrid Electric Vehicle Control Problems 288

7.1 Basics of Internal Combustion Engine Control 288

7.1.1 SI Engine Control 288

7.1.2 Diesel Engine Control 289

7.2 Engine Torque Fluctuation Dumping Control Through the Electric Motor 289

7.2.1 Sliding Mode Control 293

7.2.2 Engine Torque Fluctuation Dumping Control Based on the Sliding Mode Control Method 296

7.3 High-voltage Bus Spike Control 298

7.3.1 Bang-Bang Control Strategy of Overvoltage Protection 300

7.3.2 PID-based ON/OFF Control Strategy for Overvoltage Protection 301

7.3.3 Fuzzy-logic-based ON/OFF Control Strategy for Overvoltage Protection 301

7.4 Thermal Control of an HEV Battery System 304

7.4.1 Combined PID Feedback with Feedforward Battery Thermal System Control Strategy 306

7.4.2 Optimal Battery Thermal Control Strategy 308

7.5 HEV/EV Traction Motor Control 311

7.5.1 Traction Torque Control 311

7.5.2 Anti-rollback Control 313

7.6 Active Suspension Control in HEV/EV Systems 313

7.6.1 Suspension System Model of a Quarter Car 314

7.6.2 Active Suspension System Control 318

7.7 Adaptive Charge-sustaining Setpoint and Adaptive Recharge SOC Determination for PHEVs 325

7.7.1 Scenarios of Battery Capacity Decay and Discharge Power Capability Degradation 326

7.7.2 Adaptive Recharge SOC Termination Setpoint Control Strategy 326

7.8 Online Tuning Strategy of the SOC Lower Bound in CS Operational Mode 333

7.8.1 PHEV Charge-sustaining Operational Characteristics 333

7.8.2 PHEV Battery CS-operation SOC Lower Bound Online Tuning 335

7.9 PHEV Battery CS-operation Nominal SOC Setpoint Online Tuning 343

7.9.1 PHEV CS-operation Nominal SOC Setpoint Determination at BOL 343

7.9.2 Online Tuning Strategy of PHEV CS-operation Nominal SOC Setpoint 345

References 347

8 Plug-in Charging Characteristics, Algorithm, and Impact on the Power Distribution System 348

8.1 Introduction 348

8.2 Plug-in Hybrid Vehicle Battery System and Charging Characteristics 349

8.2.1 AC-120 Plug-in Charging Characteristics 349

8.2.2 AC-240 Plug-in Charging Characteristics 350

8.2.3 DC Fast-charging Characteristics 353

8.3 Battery Life and Safety Impacts of Plug-in Charging Current and Temperature 355

8.4 Plug-in Charging Control 355

8.4.1 AC Plug-in Charge Control 355

8.4.2 DC Fast-charging Control 358

8.5 Impacts of Plug-in Charging on the Electricity Network 360

8.5.1 Impact on the Distribution System 360

8.5.2 Impact on the Electric Grid 362

8.6 Optimal Plug-in Charging Strategy 364

8.6.1 The Optimal Plug-in Charge Back Point Determination 364

8.6.2 Cost-based Optimal Plug-in Charging Strategy 366

References 372

9 Hybrid Electric Vehicle Vibration, Noise, and Control 373

9.1 Basics of Noise and Vibration 373

9.1.1 Sound Spectra and Velocity 373

9.1.2 Basic Quantities Related to Sound 374

9.1.3 Frequency Analysis Bandwidths 380

9.1.4 Basics of Vibration 382

9.1.5 Basics of Noise and Vibration Control 389

9.2 General Description of Noise, Vibration, and Control in Hybrid Electric Vehicles 391

9.2.1 Engine Start/Stop Vibration, Noise, and Control 392

9.2.2 Electric Motor Noise, Vibration, and Control 400

9.2.3 Power Electronics Noise and Control 405

9.2.4 Battery System Noise, Vibration, and Control 408

References 411

10 Hybrid Electric Vehicle Design and Performance Analysis 412

10.1 Hybrid Electric Vehicle Simulation System 412

10.2 Typical Test Driving Cycles 414

10.2.1 Typical EPA Fuel Economy Test Schedules 414

10.2.2 Typical Supplemental Fuel Economy Test Schedules 418

10.2.3 Other Typical Test Schedules 421

10.3 Sizing Components and Vehicle Performance Analysis 430

10.3.1 Drivability Calculation 431

10.3.2 Preliminary Sizing of the Main Components of a Hybrid Electric Vehicle 433

10.4 Fuel Economy, Emissions, and Electric Mileage Calculation 454

10.4.1 Basics of Fuel Economy and Emissions Calculation 454

10.4.2 EPA Fuel Economy Label Test and Calculation 457

10.4.3 Electrical Energy Consumption and Miles per Gallon Gasoline Equivalent Calculation 463

References 478

Appendix A 480

Appendix B 520

Index 553