Soft-Switching Technology for Three-phase Power Electronics Converters IEEE Press Series on Power and Energy Systems Series

Discover foundational and advanced topics in soft-switching technology, including ZVS three-phase conversion

In Soft-Switching Technology for Three-phase Power Electronics Converters, an expert team of researchers delivers a comprehensive exploration of soft-switching three-phase converters for applications including renewable energy and distribution power systems, AC power sources, UPS, motor drives, battery chargers, and more. The authors begin with an introduction to the fundamentals of the technology, providing the basic knowledge necessary for readers to understand the following articles.

The book goes on to discuss three-phase rectifiers and three-phase grid inverters. It offers prototypes and experiments of each type of technology. Finally, the authors describe the impact of silicon carbide devices on soft-switching three-phase converters, studying the improvement in efficiency and power density created via the introduction of silicon carbide devices.

Throughout, the authors put a special focus on a family of zero-voltage switching (ZVS) three-phase converters and related pulse width modulation (PWM) schemes.

The book also includes:

• A thorough introduction to soft-switching techniques, including the classification of soft-switching for three phase converter topologies, soft-switching types and a generic soft-switching pulse-width-modulation known as Edge-Aligned PWM
• A comprehensive exploration of classical soft-switching three-phase converters, including the switching of power semiconductor devices and DC and AC side resonance
• Practical discussions of ZVS space vector modulation for three-phase converters, including the three-phase converter commutation process
• In-depth examinations of three-phase rectifiers with compound active clamping circuits

Perfect for researchers, scientists, professional engineers, and undergraduate and graduate students studying or working in power electronics, Soft-Switching Technology for Three-phase Power Electronics Converters is also a must-read resource for research and development engineers involved with the design and development of power electronics.

Preface xiii

Nomenclature xv

Part 1 Fundamental of Soft-switching 1

1 Introduction 3

1.1 Requirement of Three-phase Power Conversions 3

1.1.1 Three-phase Converters 3

1.1.2 Switching Frequency vs. Conversion Efficiency and Power Density 5

1.1.3 Switching Frequency and Impact of Soft-switching Technology 9

1.2 Concept of Soft-switching Technique 10

1.2.1 Soft-switching Types 11

1.2.2 Soft-switching Technique for Three-phase Converters 13

1.3 Applications of Soft-switching to Three-phase Converters 14

1.3.1 Renewable Energy and Power Generation 14

1.3.2 Energy Storage Systems 17

1.3.3 Distributed FACTS Devices 19

1.3.4 Uninterruptible Power Supply 19

1.3.5 Motor Drives 21

1.3.6 Fast EV Chargers 21

1.3.7 Power Supply 22

1.4 The Topics of This Book 22

References 23

2 Basics of Soft-switching Three-phase Converters 27

2.1 Introduction 27

2.2 Switching Characteristics of Three-phase Converters 28

2.2.1 Control of Three-phase Converters 28

2.2.2 Switching Transient Process and Switching Loss 31

2.2.3 Diode Turn-off and Reverse Recovery 34

2.2.4 Stray Inductance on Switching Process 35

2.2.5 Snubber 38

2.3 Classification of Soft-switching Three-phase Converters 39

2.4 DC-side Resonance Converters 40

2.4.1 Resonant DC-link Converters 40

2.4.2 Active-clamped Resonant DC-link (ACRDCL) Converter 45

2.4.3 ZVS-SVM Active-clamping Three-phase Converter 46

2.4.3.1 Active-clamping DC–DC Converter 46

2.4.3.2 Active-clamping Three-phase Converter 52

2.5 AC-side Resonance Converters 54

2.5.1 Auxiliary Resonant Commutated Pole Converter 55

2.5.2 Coupled-inductor Zero Voltage-transition (ZVT) Inverter 59

2.5.3 Zero-current Transition (ZCT) Inverter 62

2.6 Soft-switching Inverter with TCM Control 62

2.7 Summary 66

References 67

3 Soft-switching PWM Control for Active Clamped Three-phase Converters 71

3.1 Introduction 71

3.2 PWM of Three-phase Converters 72

3.3 Edge-aligned PWM 76

3.4 ZVS Active-clamping Converter with Edge-aligned PWM 77

3.4.1 Stage Analysis 78

3.4.2 ZVS Conditions 88

3.4.2.1 The First Resonant Stage 88

3.4.2.2 The Second Resonant Stage 91

3.4.2.3 Steady Conditions 93

3.4.3 Impact of PWM Scheme and Load on ZVS Condition 99

3.5 Control Diagram of the Converter with EA-PWM 105

3.6 ZVS-SVM 107

3.6.1 Vector Sequence 109

3.6.2 ZVS-SVM Scheme 111

3.6.3 Characteristics of the Converter with ZVS-SVM 113

3.7 Summary 115

References 116

Part 2 ZVS-SVM Applied to Three-phase Rectifiers 119

4 Three-phase Rectifier with Compound Active-clamping Circuit 121

4.1 Introduction 121

4.2 Operation Principle of CAC Rectifier 122

4.2.1 Space Vector of Three-phase Grid Voltage 122

4.2.2 Space Vector Modulation of Three-phase Converter 124

4.2.3 Switching Scheme of CAC Rectifier 126

4.3 Circuit Analysis 134

4.3.1 Operation Stage Analysis 134

4.3.2 Resonant Stages Analysis 138

4.3.3 Steady State Analysis 142

4.3.4 Soft-switching Condition 144

4.3.5 Control Technique of Compound Active-clamping Three-phase Rectifier 145

4.4 Prototype Design 147

4.4.1 Specifications of a 40 kW Rectifier 147

4.4.2 Parameter Design 147

4.4.3 Experiment Platform and Testing Results 151

4.5 Summary 156

References 156

5 Three-phase Rectifier with Minimum Voltage Active-clamping Circuit 159

5.1 Introduction 159

5.2 Operation Principle of MVAC Rectifier 159

5.2.1 Space Vector Modulation of Three-phase Converter 159

5.2.2 Switching Scheme of MVAC Rectifier 162

5.3 Circuit Analysis of MVAC Rectifier 168

5.3.1 Operation Stage Analysis 168

5.3.2 Resonant Stages Analysis 173

5.3.3 Steady State Analysis 177

5.3.4 Soft-switching Condition 179

5.3.5 Control Technique of Minimum Voltage Active-clamping Three-phase Rectifier 182

5.4 Prototype Design 184

5.4.1 Specifications of a 30 kW Rectifier 184

5.4.2 Parameter Design 184

5.4.3 Experiment Platform and Testing Results 187

5.5 Summary 191

References 192

Part 3 ZVS-SVM Applied to Three-phase Grid Inverters 193

6 Three-phase Grid Inverter with Minimum Voltage Active-clamping Circuit 195

6.1 Introduction 195

6.2 Operation Principle of MVAC Inverter 195

6.2.1 Space Vector of Three-phase Grid Voltage 195

6.2.2 Space Vector Modulation of Three-phase Inverter 197

6.2.3 Switching Scheme of MVAC Inverter Under Unit Power Factor 200

6.2.4 Generalized Space Vector Modulation Method of MVAC Inverter with Arbitrary Output 206

6.3 Circuit Analysis 210

6.3.1 Operation Stage Analysis 210

6.3.2 Resonant Stages Analysis 214

6.3.3 Steady-state Analysis 217

6.3.4 Soft-switching Condition 218

6.3.5 Control Technique of MVAC Inverter 219

6.4 Design Prototype 221

6.4.1 Specifications of a 30-kW Inverter 221

6.4.2 Parameter Design 222

6.4.3 Experiment Results 225

6.5 Summary 230

References 230

7 Three-phase Inverter with Compound Active-clamping Circuit 231

7.1 Introduction 231

7.2 Scheme of ZVS-SVM 232

7.2.1 Switch Commutations in Main Bridges of Three-phase Inverter 232

7.2.2 Derivation of ZVS-SVM 233

7.3 Circuit Analysis 238

7.3.1 Operation Stage Analysis 238

7.3.2 Resonant Stages Analysis 243

7.3.3 Steady-state Analysis 247

7.3.4 Soft-switching Condition 250

7.3.5 Resonant Time Comparison 250

7.4 Implementation of ZVS-SVM 252

7.4.1 Regulation of Short Circuit Stage 252

7.4.2 Implementation in Digital Controller 252

7.4.3 Control Block Diagram with ZVS-SVM 255

7.5 Prototype Design 256

7.5.1 Specifications of a 30-kW Inverter 256

7.5.2 Parameter Design 256

7.5.2.1 Requirement of Diode Reverse Recovery Suppression 256

7.5.2.2 Requirement of Voltage Stress 257

7.5.2.3 Requirement of Reducing Turn-off Loss in Auxiliary Switch 257

7.5.2.4 Requirement of Minimum Resonant Capacitance 258

7.5.2.5 Requirement of Resonant Time 258

7.5.3 Experiment Platform and Testing Results 259

7.6 Summary 263

References 263

8 Loss Analysis and Optimization of a Zero-voltage-switching Inverter 265

8.1 Introduction 265

8.2 Basic Operation Principle of the CAC ZVS Inverter 266

8.2.1 Operation Stage Analysis 266

8.2.2 ZVS Condition Derivation 272

8.3 Loss and Dimension Models 276

8.3.1 Loss Model of IGBT Devices 276

8.3.1.1 Conduction Loss of IGBT Devices 276

8.3.1.2 Switching Loss of the IGBT Devices 278

8.3.2 Loss and Dimension Models of Resonant Inductor 281

8.3.3 Loss and Dimension Models of the Filter Inductor 283

8.3.4 Dimension Model of Other Components 284

8.3.4.1 Clamping Capacitor 284

8.3.4.2 Heat Sink 285

8.4 Parameters Optimization and Design Methodology 288

8.4.1 Objective Function 288

8.4.2 Constrained Conditions 289

8.4.3 Optimization Design 290

8.5 Prototype and Experimental Results 292

8.6 Summary 295

References 296

9 Design of the Resonant Inductor 297

9.1 Introduction 297

9.2 Fundamental of Inductor 297

9.3 Design Methodology 299

9.3.1 Cross-section Area of the Core A c 300

9.3.2 Window Area A e 300

9.3.3 Area-product A p 300

9.3.4 Turns of Winding N 301

9.3.5 Length of the Air Gap l g 301

9.3.6 Winding Loss P dc 301

9.3.7 Core Loss P core 302

9.3.8 Design Procedure 303

9.4 Design Example 303

9.4.1 Barrel Winding Discussion 305

9.4.1.1 Winding Position Discussion 306

9.4.1.2 Winding Thickness Discussion 310

9.4.2 Flat Winding Discussion 311

9.4.2.1 Different Structures Comparison 311

9.4.2.2 Winding Position Discussion 314

9.5 Design Verification 317

9.5.1 Simulation Verification 317

9.5.2 Experimental Verification 318

9.6 Summary 320

References 320

Part 4 Impact of SiC Device on Soft-switching Grid Inverters 321

10 Soft-switching SiC Three-phase Grid Inverter 323

10.1 Introduction 323

10.2 Soft-switching Three-phase Inverter 324

10.2.1 SVM Scheme in Hard-switching Inverter 324

10.2.2 ZVS-SVM Scheme in Soft-switching Inverter 326

10.2.3 Operation Stages and ZVS Condition of Soft-switching Inverter 326

10.2.3.1 Operation Stages Analysis 326

10.2.3.2 ZVS Condition Derivation 329

10.3 Efficiency Comparison of Hard-switching SiC Inverter and Soft-switching SiC Inverter 334

10.3.1 Parameters Design of Soft-switching SiC Inverter 334

10.3.1.1 AC Filter Inductor 335

10.3.1.2 Resonant Parameters 335

10.3.1.3 dc Filter Capacitor 338

10.3.1.4 Clamping Capacitor 338

10.3.1.5 Cores Selection 341

10.3.1.6 Switching Loss Measurement 342

10.3.2 Comparison of Two SiC Inverters 344

10.3.2.1 Loss Distributions 345

10.3.2.2 Efficiency Stiffness 347

10.3.2.3 Passive Components Volumes 348

10.3.3 Experimental Verification 348

10.3.3.1 Efficiency Test 348

10.3.3.2 Passive Components Volumes Comparison 350

10.4 Design of Low Stray Inductance Layout in Soft-switching SiC Inverter 350

10.4.1 Oscillation Model 350

10.4.2 Design of Low Stray Inductance 7-in-1 SiC Power Module 353

10.4.3 7-in-1 SiC Power Module Prototype and Testing Results 356

10.4.3.1 Stray Inductance Measurement 356

10.4.3.2 Voltage Stress Comparison 358

10.5 Design of Low Loss Resonant Inductor in Soft-switching SiC Inverter 359

10.5.1 Impact of Distributed Air Gap 359

10.5.2 Optimal Flux Density Investigation 360

10.5.3 Optimal Winding Foil Thickness Investigation 360

10.5.4 Resonant Inductor Prototypes and Loss Measurement 364

10.6 Summary 368

References 368

11 Soft-switching SiC Single-phase Grid Inverter with Active Power Decoupling 371

11.1 Introduction 371

11.1.1 Modulation Methods for Single-phase Inverter 371

11.1.2 APD in Single-phase Grid Inverter 372

11.2 Operation Principle 376

11.2.1 Topology and Switching Scheme 376

11.2.2 Stage Analysis 379

11.3 Circuit Analysis 385

11.3.1 Resonant Stages Analysis 385

11.3.2 Steady-state Analysis 387

11.3.3 Soft-switching Condition 388

11.3.4 Short Circuit Current 388

11.4 Design Prototype 390

11.4.1 Rated Parameters of a 1.5-kW Inverter 390

11.4.2 Parameter Design 391

11.4.3 Experimental Platform and Testing Results 393

11.5 Summary 398

References 398

12 Soft-switching SiC Three-phase Four-wire Back-to-back Converter 401

12.1 Introduction 401

12.2 Operation Principle 402

12.2.1 Commutations Analysis 403

12.2.2 Operation Scheme 403

12.2.3 Stage Analysis 405

12.3 Circuit Analysis 414

12.3.1 Resonant Stage Analysis 414

12.3.2 Steady State Analysis 417

12.3.3 ZVS Condition 422

12.4 Design Prototype 423

12.4.1 Parameters Design 423

12.4.2 Loss Analysis 427

12.4.3 Experimental Results 431

12.5 Summary 440

References 440

Appendix 441

A.1 Basic of SVM 441

A.2 Switching Patterns of SVM 12 446

A.3 Switching Patterns of ZVS-SVM 448

A.4 Inverter Loss Models 450

A.4.1 Loss Model of Hard-switching Three-phase Grid Inverter 450

A.4.1.1 Conducting Loss 450

A.4.1.2 Switching Loss 453

A.4.1.3 AC Filter Inductor Loss and Volume Estimations 454

A.4.2 Loss Model of Soft-switching Three-phase Grid Inverter 456

A.4.2.1 Loss in Main Switches 456

A.4.2.2 Loss in Auxiliary Switch 458

A.4.2.3 Loss and Volume of Filter Inductor and Resonant Inductor 459

A.5 AC Filter Inductance Calculation 459

A.6 DC Filter Capacitance Calculation 462

Index 469

Dehong Xu, PhD, is Full Professor in College of Electrical Engineering at Zhejiang University.

Rui Li, PhD, is Full Professor in the Department of Electrical Engineering, School of Electronics, Information and Electrical Engineering at Shanghai Jiao Tong University.

Ning He, PhD, is Firmware Design Principal Engineer in Delta Electronics (Shanghai) Co., Ltd.

Jinyi Deng is a PhD student in Power Electronics in the College of Electrical Engineering at Zhejiang University.

Yuying Wu is a PhD student in Power Electronics in the College of Electrical Engineering at Zhejiang University.