Advanced Control of Doubly Fed Induction Generator for Wind Power Systems

Covers the fundamental concepts and advanced modelling techniques of Doubly Fed Induction Generators accompanied by analyses and simulation results

Filled with illustrations, problems, models, analyses, case studies, selected simulation and experimental results, Advanced Control of Doubly Fed Induction Generator for Wind Power Systems provides the basic concepts for modelling and controlling of Doubly Fed Induction Generator (DFIG) wind power systems and their power converters. It explores both the challenges and concerns of DFIG under a non-ideal grid and introduces the control strategies and effective operations performance options of DFIG under a non-ideal grid. 

Other topics of this book include thermal analysis of DFIG wind power converters under grid faults; implications of the DFIG test bench; advanced control of DFIG under harmonic distorted grid voltage, including multiple-loop and resonant control; modeling of DFIG and GSC under unbalanced grid voltage; the LFRT of DFIG, including the recurring faults ride through of DFIG; and more. In addition, this resource:

• Explores the challenges and concerns of Doubly Fed Induction Generators (DFIG) under non-ideal grid
• Discusses basic concepts of DFIG wind power system and vector control schemes of DFIG
• Introduces control strategies under a non-ideal grid
• Includes case studies and simulation and experimental results

Advanced Control of Doubly Fed Induction Generator for Wind Power Systems is an ideal book for graduate students studying renewable energy and power electronics as well as for research and development engineers working with wind power converters.

DEHONG XU, PHD, is a Professor in the College of Electrical Engineering of Zhejiang University, China, where he teaches modelling and control of power electronics and renewable systems.

FREDE BLAABJERG, PHD, is a Professor in Power Electronics and Villum Investigator at the Department of Energy Technology, Aalborg University, Denmark, as well as a Visiting Professor at Zhejiang University, China.

WENJIE CHEN received a PhD from the College of Electrical Engineering of Zhejiang University. Now he is a senior engineer in Powertrain Solution Division, BOSCH.

NAN ZHU received a PhD from the College of Electrical Engineering of Zhejiang University. Now he is a senior engineer in the renewable energy division of Huawei.

PREFACE xiii

NOMENCLATURE xv

PART I INTRODUCTION TO WIND POWER GENERATION

CHAPTER 1 INTRODUCTION 3

1.1 Global Wind Power Development 3

1.2 Evolution of Wind Power System 5

1.3 Power Electronics in Wind Turbine Systems 9

1.4 Challenges and Trends in Future Wind Power Technology 11

1.5 The Topics of This Book 18

CHAPTER 2 BASICS OF WIND POWER GENERATION SYSTEM 21

2.1 Introduction 21

2.2 Wind Power Concept 21

2.3 Variable-Speed Wind Turbine 26

2.4 Control of Power Converter 31

2.5 Wind Power Transmission 34

2.6 Summary 41

CHAPTER 3 GRID CODES FOR WIND POWER GENERATION SYSTEMS 43

3.1 Introduction 43

3.2 Grid Code Requirements Under Normal Operation 44

3.3 Grid Code Requirements Under Non-Ideal Grid 51

3.4 Grid Codes for Distributed Wind Power Generation 58

3.5 Summary 62

PART II MODELING AND CONTROL OF DFIG

CHAPTER 4 MODELING OF DFIG WIND POWER SYSTEMS 67

4.1 Introduction 67

4.2 Steady-State Equivalent Circuit of a DFIG 67

4.3 Dynamic Model of a DFIG 74

4.4 Modeling of the Converter 85

4.5 Summary 95

CHAPTER 5 CONTROL OF DFIG POWER CONVERTERS 99

5.1 Introduction 99

5.2 Start-Up Process of the DFIG System 99

5.3 Grid-Side Converter 101

5.4 Rotor-Side Converter in Power-Control Mode 114

5.5 Rotor-Side Converter in Speed-Control Mode 124

5.6 Rotor-Side Converter in Starting Mode 128

5.7 Control-Mode Switching 135

5.8 Summary 136

PART III OPERATION OF DFIG UNDER DISTORTED GRID VOLTAGE

CHAPTER 6 ANALYSIS OF DFIG UNDER DISTORTED GRID VOLTAGE 141

6.1 Introduction 141

6.2 Influence on GSC 142

6.3 Influence on DFIG and RSC 149

6.4 Discussion on Different Controller Parameters 162

6.5 Discussion on Different Power Scales 163

6.6 Summary 164

CHAPTER 7 MULTIPLE-LOOP CONTROL OF DFIG UNDER DISTORTED GRID VOLTAGE 167

7.1 Introduction 167

7.2 GSC Control 168

7.3 DFIG and RSC Control 176

7.4 Influence on the Fundamental Current Loop 188

7.5 Summary 191

CHAPTER 8 RESONANT CONTROL OF DFIG UNDER GRID VOLTAGE HARMONICS DISTORTION 195

8.1 Introduction 195

8.2 Resonant Controller 195

8.3 Stator Current Control Using Resonant Controllers 197

8.4 Influence on Normal Control Loop 215

8.5 Design and Optimization of Current Controller 222

8.6 Summary 233

CHAPTER 9 DFIG UNDER UNBALANCED GRID VOLTAGE 237

9.1 Introduction 237

9.2 RSC and DFIG Under Unbalanced Grid Voltage 237

9.3 GSC Under Unbalanced Grid Voltage 244

9.4 Control Limitations Under Unbalanced Grid Voltage 248

9.5 Summary 256

CHAPTER 10 CONTROL OF DFIG WIND POWER SYSTEM UNDER UNBALANCED GRID VOLTAGE 259

10.1 Introduction 259

10.2 Control Targets 259

10.3 Stator Current Control with Resonant Controller 260

10.4 DC Voltage Fluctuation Control by GSC 266

10.5 Summary 293

PART IV GRID FAULT RIDE-THROUGH OF DFIG

CHAPTER 11 DYNAMIC MODEL OF DFIG UNDER GRID FAULTS 299

11.1 Introduction 299

11.2 Behavior During Voltage Dips 300

11.3 DFIG Behavior During Voltage Recovery 315

11.4 Under Recurring Grid Faults 320

11.5 Summary 339

CONTENTS xi

CHAPTER 12 GRID FAULT RIDE-THROUGH OF DFIG 341

12.1 Introduction 341

12.2 PLL Under Grid Faults 342

12.3 FRT Strategies for DFIG Based on Improved Control 348

12.4 FRT Strategies Based on Hardware Solutions 362

12.5 Recurring Fault Ride Through 369

12.6 Summary 384

CHAPTER 13 THERMAL CONTROL OF POWER CONVERTER IN NORMAL AND ABNORMAL OPERATIONS 387

13.1 Loss Model of Power Converter 387

13.2 Thermal Model of Power Converter 392

13.3 Thermal Loading During Normal Operation 397

13.4 Thermal Loading in Abnormal Operation 401

13.5 Smart Thermal Control by Reactive Power Circulation 408

13.6 Summary 412

PART V DFIG TEST BENCH

CHAPTER 14 DFIG TEST BENCH 417

14.1 Introduction 417

14.2 Scheme of the DFIG Test Bench 417

14.3 The Caged Motor and its Driving Inverter 419

14.4 DFIG Test System 420

14.5 Rotor-Side Crowbar 429

14.6 Grid Emulator 431

14.7 Communications and Up-Level Control 439

14.8 Start-Up and Protection of the System 441

14.9 Summary 448

APPENDIX 449

A.1 Flux Equations in α β Reference Frame 449

A.2 Typical Parameters of a DFIG 451

INDEX 453

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