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.

• Preface xiiiNomenclature xvPart 1 Fundamental of Soft-switching 11 Introduction 31.1 Requirement of Three-phase Power Conversions 31.1.1 Three-phase Converters 31.1.2 Switching Frequency vs. Conversion Efficiency and Power Density 51.1.3 Switching Frequency and Impact of Soft-switching Technology 91.2 Concept of Soft-switching Technique 101.2.1 Soft-switching Types 111.2.2 Soft-switching Technique for Three-phase Converters 131.3 Applications of Soft-switching to Three-phase Converters 141.3.1 Renewable Energy and Power Generation 141.3.2 Energy Storage Systems 171.3.3 Distributed FACTS Devices 191.3.4 Uninterruptible Power Supply 191.3.5 Motor Drives 211.3.6 Fast EV Chargers 211.3.7 Power Supply 221.4 The Topics of This Book 22References 232 Basics of Soft-switching Three-phase Converters 272.1 Introduction 272.2 Switching Characteristics of Three-phase Converters 282.2.1 Control of Three-phase Converters 282.2.2 Switching Transient Process and Switching Loss 312.2.3 Diode Turn-off and Reverse Recovery 342.2.4 Stray Inductance on Switching Process 352.2.5 Snubber 382.3 Classification of Soft-switching Three-phase Converters 392.4 DC-side Resonance Converters 402.4.1 Resonant DC-link Converters 402.4.2 Active-clamped Resonant DC-link (ACRDCL) Converter 452.4.3 ZVS-SVM Active-clamping Three-phase Converter 462.4.3.1 Active-clamping DC–DC Converter 462.4.3.2 Active-clamping Three-phase Converter 522.5 AC-side Resonance Converters 542.5.1 Auxiliary Resonant Commutated Pole Converter 552.5.2 Coupled-inductor Zero Voltage-transition (ZVT) Inverter 592.5.3 Zero-current Transition (ZCT) Inverter 622.6 Soft-switching Inverter with TCM Control 622.7 Summary 66References 673 Soft-switching PWM Control for Active Clamped Three-phase Converters 713.1 Introduction 713.2 PWM of Three-phase Converters 723.3 Edge-aligned PWM 763.4 ZVS Active-clamping Converter with Edge-aligned PWM 773.4.1 Stage Analysis 783.4.2 ZVS Conditions 883.4.2.1 The First Resonant Stage 883.4.2.2 The Second Resonant Stage 913.4.2.3 Steady Conditions 933.4.3 Impact of PWM Scheme and Load on ZVS Condition 993.5 Control Diagram of the Converter with EA-PWM 1053.6 ZVS-SVM 1073.6.1 Vector Sequence 1093.6.2 ZVS-SVM Scheme 1113.6.3 Characteristics of the Converter with ZVS-SVM 1133.7 Summary 115References 116Part 2 ZVS-SVM Applied to Three-phase Rectifiers 1194 Three-phase Rectifier with Compound Active-clamping Circuit 1214.1 Introduction 1214.2 Operation Principle of CAC Rectifier 1224.2.1 Space Vector of Three-phase Grid Voltage 1224.2.2 Space Vector Modulation of Three-phase Converter 1244.2.3 Switching Scheme of CAC Rectifier 1264.3 Circuit Analysis 1344.3.1 Operation Stage Analysis 1344.3.2 Resonant Stages Analysis 1384.3.3 Steady State Analysis 1424.3.4 Soft-switching Condition 1444.3.5 Control Technique of Compound Active-clamping Three-phase Rectifier 1454.4 Prototype Design 1474.4.1 Specifications of a 40 kW Rectifier 1474.4.2 Parameter Design 1474.4.3 Experiment Platform and Testing Results 1514.5 Summary 156References 1565 Three-phase Rectifier with Minimum Voltage Active-clamping Circuit 1595.1 Introduction 1595.2 Operation Principle of MVAC Rectifier 1595.2.1 Space Vector Modulation of Three-phase Converter 1595.2.2 Switching Scheme of MVAC Rectifier 1625.3 Circuit Analysis of MVAC Rectifier 1685.3.1 Operation Stage Analysis 1685.3.2 Resonant Stages Analysis 1735.3.3 Steady State Analysis 1775.3.4 Soft-switching Condition 1795.3.5 Control Technique of Minimum Voltage Active-clamping Three-phase Rectifier 1825.4 Prototype Design 1845.4.1 Specifications of a 30 kW Rectifier 1845.4.2 Parameter Design 1845.4.3 Experiment Platform and Testing Results 1875.5 Summary 191References 192Part 3 ZVS-SVM Applied to Three-phase Grid Inverters 1936 Three-phase Grid Inverter with Minimum Voltage Active-clamping Circuit 1956.1 Introduction 1956.2 Operation Principle of MVAC Inverter 1956.2.1 Space Vector of Three-phase Grid Voltage 1956.2.2 Space Vector Modulation of Three-phase Inverter 1976.2.3 Switching Scheme of MVAC Inverter Under Unit Power Factor 2006.2.4 Generalized Space Vector Modulation Method of MVAC Inverter with Arbitrary Output 2066.3 Circuit Analysis 2106.3.1 Operation Stage Analysis 2106.3.2 Resonant Stages Analysis 2146.3.3 Steady-state Analysis 2176.3.4 Soft-switching Condition 2186.3.5 Control Technique of MVAC Inverter 2196.4 Design Prototype 2216.4.1 Specifications of a 30-kW Inverter 2216.4.2 Parameter Design 2226.4.3 Experiment Results 2256.5 Summary 230References 2307 Three-phase Inverter with Compound Active-clamping Circuit 2317.1 Introduction 2317.2 Scheme of ZVS-SVM 2327.2.1 Switch Commutations in Main Bridges of Three-phase Inverter 2327.2.2 Derivation of ZVS-SVM 2337.3 Circuit Analysis 2387.3.1 Operation Stage Analysis 2387.3.2 Resonant Stages Analysis 2437.3.3 Steady-state Analysis 2477.3.4 Soft-switching Condition 2507.3.5 Resonant Time Comparison 2507.4 Implementation of ZVS-SVM 2527.4.1 Regulation of Short Circuit Stage 2527.4.2 Implementation in Digital Controller 2527.4.3 Control Block Diagram with ZVS-SVM 2557.5 Prototype Design 2567.5.1 Specifications of a 30-kW Inverter 2567.5.2 Parameter Design 2567.5.2.1 Requirement of Diode Reverse Recovery Suppression 2567.5.2.2 Requirement of Voltage Stress 2577.5.2.3 Requirement of Reducing Turn-off Loss in Auxiliary Switch 2577.5.2.4 Requirement of Minimum Resonant Capacitance 2587.5.2.5 Requirement of Resonant Time 2587.5.3 Experiment Platform and Testing Results 2597.6 Summary 263References 2638 Loss Analysis and Optimization of a Zero-voltage-switching Inverter 2658.1 Introduction 2658.2 Basic Operation Principle of the CAC ZVS Inverter 2668.2.1 Operation Stage Analysis 2668.2.2 ZVS Condition Derivation 2728.3 Loss and Dimension Models 2768.3.1 Loss Model of IGBT Devices 2768.3.1.1 Conduction Loss of IGBT Devices 2768.3.1.2 Switching Loss of the IGBT Devices 2788.3.2 Loss and Dimension Models of Resonant Inductor 2818.3.3 Loss and Dimension Models of the Filter Inductor 2838.3.4 Dimension Model of Other Components 2848.3.4.1 Clamping Capacitor 2848.3.4.2 Heat Sink 2858.4 Parameters Optimization and Design Methodology 2888.4.1 Objective Function 2888.4.2 Constrained Conditions 2898.4.3 Optimization Design 2908.5 Prototype and Experimental Results 2928.6 Summary 295References 2969 Design of the Resonant Inductor 2979.1 Introduction 2979.2 Fundamental of Inductor 2979.3 Design Methodology 2999.3.1 Cross-section Area of the Core A c 3009.3.2 Window Area A e 3009.3.3 Area-product A p 3009.3.4 Turns of Winding N 3019.3.5 Length of the Air Gap l g 3019.3.6 Winding Loss P dc 3019.3.7 Core Loss P core 3029.3.8 Design Procedure 3039.4 Design Example 3039.4.1 Barrel Winding Discussion 3059.4.1.1 Winding Position Discussion 3069.4.1.2 Winding Thickness Discussion 3109.4.2 Flat Winding Discussion 3119.4.2.1 Different Structures Comparison 3119.4.2.2 Winding Position Discussion 3149.5 Design Verification 3179.5.1 Simulation Verification 3179.5.2 Experimental Verification 3189.6 Summary 320References 320Part 4 Impact of SiC Device on Soft-switching Grid Inverters 32110 Soft-switching SiC Three-phase Grid Inverter 32310.1 Introduction 32310.2 Soft-switching Three-phase Inverter 32410.2.1 SVM Scheme in Hard-switching Inverter 32410.2.2 ZVS-SVM Scheme in Soft-switching Inverter 32610.2.3 Operation Stages and ZVS Condition of Soft-switching Inverter 32610.2.3.1 Operation Stages Analysis 32610.2.3.2 ZVS Condition Derivation 32910.3 Efficiency Comparison of Hard-switching SiC Inverter and Soft-switching SiC Inverter 33410.3.1 Parameters Design of Soft-switching SiC Inverter 33410.3.1.1 AC Filter Inductor 33510.3.1.2 Resonant Parameters 33510.3.1.3 dc Filter Capacitor 33810.3.1.4 Clamping Capacitor 33810.3.1.5 Cores Selection 34110.3.1.6 Switching Loss Measurement 34210.3.2 Comparison of Two SiC Inverters 34410.3.2.1 Loss Distributions 34510.3.2.2 Efficiency Stiffness 34710.3.2.3 Passive Components Volumes 34810.3.3 Experimental Verification 34810.3.3.1 Efficiency Test 34810.3.3.2 Passive Components Volumes Comparison 35010.4 Design of Low Stray Inductance Layout in Soft-switching SiC Inverter 35010.4.1 Oscillation Model 35010.4.2 Design of Low Stray Inductance 7-in-1 SiC Power Module 35310.4.3 7-in-1 SiC Power Module Prototype and Testing Results 35610.4.3.1 Stray Inductance Measurement 35610.4.3.2 Voltage Stress Comparison 35810.5 Design of Low Loss Resonant Inductor in Soft-switching SiC Inverter 35910.5.1 Impact of Distributed Air Gap 35910.5.2 Optimal Flux Density Investigation 36010.5.3 Optimal Winding Foil Thickness Investigation 36010.5.4 Resonant Inductor Prototypes and Loss Measurement 36410.6 Summary 368References 36811 Soft-switching SiC Single-phase Grid Inverter with Active Power Decoupling 37111.1 Introduction 37111.1.1 Modulation Methods for Single-phase Inverter 37111.1.2 APD in Single-phase Grid Inverter 37211.2 Operation Principle 37611.2.1 Topology and Switching Scheme 37611.2.2 Stage Analysis 37911.3 Circuit Analysis 38511.3.1 Resonant Stages Analysis 38511.3.2 Steady-state Analysis 38711.3.3 Soft-switching Condition 38811.3.4 Short Circuit Current 38811.4 Design Prototype 39011.4.1 Rated Parameters of a 1.5-kW Inverter 39011.4.2 Parameter Design 39111.4.3 Experimental Platform and Testing Results 39311.5 Summary 398References 39812 Soft-switching SiC Three-phase Four-wire Back-to-back Converter 40112.1 Introduction 40112.2 Operation Principle 40212.2.1 Commutations Analysis 40312.2.2 Operation Scheme 40312.2.3 Stage Analysis 40512.3 Circuit Analysis 41412.3.1 Resonant Stage Analysis 41412.3.2 Steady State Analysis 41712.3.3 ZVS Condition 42212.4 Design Prototype 42312.4.1 Parameters Design 42312.4.2 Loss Analysis 42712.4.3 Experimental Results 43112.5 Summary 440References 440Appendix 441A.1 Basic of SVM 441A.2 Switching Patterns of SVM 12 446A.3 Switching Patterns of ZVS-SVM 448A.4 Inverter Loss Models 450A.4.1 Loss Model of Hard-switching Three-phase Grid Inverter 450A.4.1.1 Conducting Loss 450A.4.1.2 Switching Loss 453A.4.1.3 AC Filter Inductor Loss and Volume Estimations 454A.4.2 Loss Model of Soft-switching Three-phase Grid Inverter 456A.4.2.1 Loss in Main Switches 456A.4.2.2 Loss in Auxiliary Switch 458A.4.2.3 Loss and Volume of Filter Inductor and Resonant Inductor 459A.5 AC Filter Inductance Calculation 459A.6 DC Filter Capacitance Calculation 462Index 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.

• Preface xiiiNomenclature xvPart 1 Fundamental of Soft-switching 11 Introduction 31.1 Requirement of Three-phase Power Conversions 31.1.1 Three-phase Converters 31.1.2 Switching Frequency vs. Conversion Efficiency and Power Density 51.1.3 Switching Frequency and Impact of Soft-switching Technology 91.2 Concept of Soft-switching Technique 101.2.1 Soft-switching Types 111.2.2 Soft-switching Technique for Three-phase Converters 131.3 Applications of Soft-switching to Three-phase Converters 141.3.1 Renewable Energy and Power Generation 141.3.2 Energy Storage Systems 171.3.3 Distributed FACTS Devices 191.3.4 Uninterruptible Power Supply 191.3.5 Motor Drives 211.3.6 Fast EV Chargers 211.3.7 Power Supply 221.4 The Topics of This Book 22References 232 Basics of Soft-switching Three-phase Converters 272.1 Introduction 272.2 Switching Characteristics of Three-phase Converters 282.2.1 Control of Three-phase Converters 282.2.2 Switching Transient Process and Switching Loss 312.2.3 Diode Turn-off and Reverse Recovery 342.2.4 Stray Inductance on Switching Process 352.2.5 Snubber 382.3 Classification of Soft-switching Three-phase Converters 392.4 DC-side Resonance Converters 402.4.1 Resonant DC-link Converters 402.4.2 Active-clamped Resonant DC-link (ACRDCL) Converter 452.4.3 ZVS-SVM Active-clamping Three-phase Converter 462.4.3.1 Active-clamping DC–DC Converter 462.4.3.2 Active-clamping Three-phase Converter 522.5 AC-side Resonance Converters 542.5.1 Auxiliary Resonant Commutated Pole Converter 552.5.2 Coupled-inductor Zero Voltage-transition (ZVT) Inverter 592.5.3 Zero-current Transition (ZCT) Inverter 622.6 Soft-switching Inverter with TCM Control 622.7 Summary 66References 673 Soft-switching PWM Control for Active Clamped Three-phase Converters 713.1 Introduction 713.2 PWM of Three-phase Converters 723.3 Edge-aligned PWM 763.4 ZVS Active-clamping Converter with Edge-aligned PWM 773.4.1 Stage Analysis 783.4.2 ZVS Conditions 883.4.2.1 The First Resonant Stage 883.4.2.2 The Second Resonant Stage 913.4.2.3 Steady Conditions 933.4.3 Impact of PWM Scheme and Load on ZVS Condition 993.5 Control Diagram of the Converter with EA-PWM 1053.6 ZVS-SVM 1073.6.1 Vector Sequence 1093.6.2 ZVS-SVM Scheme 1113.6.3 Characteristics of the Converter with ZVS-SVM 1133.7 Summary 115References 116Part 2 ZVS-SVM Applied to Three-phase Rectifiers 1194 Three-phase Rectifier with Compound Active-clamping Circuit 1214.1 Introduction 1214.2 Operation Principle of CAC Rectifier 1224.2.1 Space Vector of Three-phase Grid Voltage 1224.2.2 Space Vector Modulation of Three-phase Converter 1244.2.3 Switching Scheme of CAC Rectifier 1264.3 Circuit Analysis 1344.3.1 Operation Stage Analysis 1344.3.2 Resonant Stages Analysis 1384.3.3 Steady State Analysis 1424.3.4 Soft-switching Condition 1444.3.5 Control Technique of Compound Active-clamping Three-phase Rectifier 1454.4 Prototype Design 1474.4.1 Specifications of a 40 kW Rectifier 1474.4.2 Parameter Design 1474.4.3 Experiment Platform and Testing Results 1514.5 Summary 156References 1565 Three-phase Rectifier with Minimum Voltage Active-clamping Circuit 1595.1 Introduction 1595.2 Operation Principle of MVAC Rectifier 1595.2.1 Space Vector Modulation of Three-phase Converter 1595.2.2 Switching Scheme of MVAC Rectifier 1625.3 Circuit Analysis of MVAC Rectifier 1685.3.1 Operation Stage Analysis 1685.3.2 Resonant Stages Analysis 1735.3.3 Steady State Analysis 1775.3.4 Soft-switching Condition 1795.3.5 Control Technique of Minimum Voltage Active-clamping Three-phase Rectifier 1825.4 Prototype Design 1845.4.1 Specifications of a 30 kW Rectifier 1845.4.2 Parameter Design 1845.4.3 Experiment Platform and Testing Results 1875.5 Summary 191References 192Part 3 ZVS-SVM Applied to Three-phase Grid Inverters 1936 Three-phase Grid Inverter with Minimum Voltage Active-clamping Circuit 1956.1 Introduction 1956.2 Operation Principle of MVAC Inverter 1956.2.1 Space Vector of Three-phase Grid Voltage 1956.2.2 Space Vector Modulation of Three-phase Inverter 1976.2.3 Switching Scheme of MVAC Inverter Under Unit Power Factor 2006.2.4 Generalized Space Vector Modulation Method of MVAC Inverter with Arbitrary Output 2066.3 Circuit Analysis 2106.3.1 Operation Stage Analysis 2106.3.2 Resonant Stages Analysis 2146.3.3 Steady-state Analysis 2176.3.4 Soft-switching Condition 2186.3.5 Control Technique of MVAC Inverter 2196.4 Design Prototype 2216.4.1 Specifications of a 30-kW Inverter 2216.4.2 Parameter Design 2226.4.3 Experiment Results 2256.5 Summary 230References 2307 Three-phase Inverter with Compound Active-clamping Circuit 2317.1 Introduction 2317.2 Scheme of ZVS-SVM 2327.2.1 Switch Commutations in Main Bridges of Three-phase Inverter 2327.2.2 Derivation of ZVS-SVM 2337.3 Circuit Analysis 2387.3.1 Operation Stage Analysis 2387.3.2 Resonant Stages Analysis 2437.3.3 Steady-state Analysis 2477.3.4 Soft-switching Condition 2507.3.5 Resonant Time Comparison 2507.4 Implementation of ZVS-SVM 2527.4.1 Regulation of Short Circuit Stage 2527.4.2 Implementation in Digital Controller 2527.4.3 Control Block Diagram with ZVS-SVM 2557.5 Prototype Design 2567.5.1 Specifications of a 30-kW Inverter 2567.5.2 Parameter Design 2567.5.2.1 Requirement of Diode Reverse Recovery Suppression 2567.5.2.2 Requirement of Voltage Stress 2577.5.2.3 Requirement of Reducing Turn-off Loss in Auxiliary Switch 2577.5.2.4 Requirement of Minimum Resonant Capacitance 2587.5.2.5 Requirement of Resonant Time 2587.5.3 Experiment Platform and Testing Results 2597.6 Summary 263References 2638 Loss Analysis and Optimization of a Zero-voltage-switching Inverter 2658.1 Introduction 2658.2 Basic Operation Principle of the CAC ZVS Inverter 2668.2.1 Operation Stage Analysis 2668.2.2 ZVS Condition Derivation 2728.3 Loss and Dimension Models 2768.3.1 Loss Model of IGBT Devices 2768.3.1.1 Conduction Loss of IGBT Devices 2768.3.1.2 Switching Loss of the IGBT Devices 2788.3.2 Loss and Dimension Models of Resonant Inductor 2818.3.3 Loss and Dimension Models of the Filter Inductor 2838.3.4 Dimension Model of Other Components 2848.3.4.1 Clamping Capacitor 2848.3.4.2 Heat Sink 2858.4 Parameters Optimization and Design Methodology 2888.4.1 Objective Function 2888.4.2 Constrained Conditions 2898.4.3 Optimization Design 2908.5 Prototype and Experimental Results 2928.6 Summary 295References 2969 Design of the Resonant Inductor 2979.1 Introduction 2979.2 Fundamental of Inductor 2979.3 Design Methodology 2999.3.1 Cross-section Area of the Core A c 3009.3.2 Window Area A e 3009.3.3 Area-product A p 3009.3.4 Turns of Winding N 3019.3.5 Length of the Air Gap l g 3019.3.6 Winding Loss P dc 3019.3.7 Core Loss P core 3029.3.8 Design Procedure 3039.4 Design Example 3039.4.1 Barrel Winding Discussion 3059.4.1.1 Winding Position Discussion 3069.4.1.2 Winding Thickness Discussion 3109.4.2 Flat Winding Discussion 3119.4.2.1 Different Structures Comparison 3119.4.2.2 Winding Position Discussion 3149.5 Design Verification 3179.5.1 Simulation Verification 3179.5.2 Experimental Verification 3189.6 Summary 320References 320Part 4 Impact of SiC Device on Soft-switching Grid Inverters 32110 Soft-switching SiC Three-phase Grid Inverter 32310.1 Introduction 32310.2 Soft-switching Three-phase Inverter 32410.2.1 SVM Scheme in Hard-switching Inverter 32410.2.2 ZVS-SVM Scheme in Soft-switching Inverter 32610.2.3 Operation Stages and ZVS Condition of Soft-switching Inverter 32610.2.3.1 Operation Stages Analysis 32610.2.3.2 ZVS Condition Derivation 32910.3 Efficiency Comparison of Hard-switching SiC Inverter and Soft-switching SiC Inverter 33410.3.1 Parameters Design of Soft-switching SiC Inverter 33410.3.1.1 AC Filter Inductor 33510.3.1.2 Resonant Parameters 33510.3.1.3 dc Filter Capacitor 33810.3.1.4 Clamping Capacitor 33810.3.1.5 Cores Selection 34110.3.1.6 Switching Loss Measurement 34210.3.2 Comparison of Two SiC Inverters 34410.3.2.1 Loss Distributions 34510.3.2.2 Efficiency Stiffness 34710.3.2.3 Passive Components Volumes 34810.3.3 Experimental Verification 34810.3.3.1 Efficiency Test 34810.3.3.2 Passive Components Volumes Comparison 35010.4 Design of Low Stray Inductance Layout in Soft-switching SiC Inverter 35010.4.1 Oscillation Model 35010.4.2 Design of Low Stray Inductance 7-in-1 SiC Power Module 35310.4.3 7-in-1 SiC Power Module Prototype and Testing Results 35610.4.3.1 Stray Inductance Measurement 35610.4.3.2 Voltage Stress Comparison 35810.5 Design of Low Loss Resonant Inductor in Soft-switching SiC Inverter 35910.5.1 Impact of Distributed Air Gap 35910.5.2 Optimal Flux Density Investigation 36010.5.3 Optimal Winding Foil Thickness Investigation 36010.5.4 Resonant Inductor Prototypes and Loss Measurement 36410.6 Summary 368References 36811 Soft-switching SiC Single-phase Grid Inverter with Active Power Decoupling 37111.1 Introduction 37111.1.1 Modulation Methods for Single-phase Inverter 37111.1.2 APD in Single-phase Grid Inverter 37211.2 Operation Principle 37611.2.1 Topology and Switching Scheme 37611.2.2 Stage Analysis 37911.3 Circuit Analysis 38511.3.1 Resonant Stages Analysis 38511.3.2 Steady-state Analysis 38711.3.3 Soft-switching Condition 38811.3.4 Short Circuit Current 38811.4 Design Prototype 39011.4.1 Rated Parameters of a 1.5-kW Inverter 39011.4.2 Parameter Design 39111.4.3 Experimental Platform and Testing Results 39311.5 Summary 398References 39812 Soft-switching SiC Three-phase Four-wire Back-to-back Converter 40112.1 Introduction 40112.2 Operation Principle 40212.2.1 Commutations Analysis 40312.2.2 Operation Scheme 40312.2.3 Stage Analysis 40512.3 Circuit Analysis 41412.3.1 Resonant Stage Analysis 41412.3.2 Steady State Analysis 41712.3.3 ZVS Condition 42212.4 Design Prototype 42312.4.1 Parameters Design 42312.4.2 Loss Analysis 42712.4.3 Experimental Results 43112.5 Summary 440References 440Appendix 441A.1 Basic of SVM 441A.2 Switching Patterns of SVM 12 446A.3 Switching Patterns of ZVS-SVM 448A.4 Inverter Loss Models 450A.4.1 Loss Model of Hard-switching Three-phase Grid Inverter 450A.4.1.1 Conducting Loss 450A.4.1.2 Switching Loss 453A.4.1.3 AC Filter Inductor Loss and Volume Estimations 454A.4.2 Loss Model of Soft-switching Three-phase Grid Inverter 456A.4.2.1 Loss in Main Switches 456A.4.2.2 Loss in Auxiliary Switch 458A.4.2.3 Loss and Volume of Filter Inductor and Resonant Inductor 459A.5 AC Filter Inductance Calculation 459A.6 DC Filter Capacitance Calculation 462Index 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.

• Preface xiiiNomenclature xvPart 1 Fundamental of Soft-switching 11 Introduction 31.1 Requirement of Three-phase Power Conversions 31.1.1 Three-phase Converters 31.1.2 Switching Frequency vs. Conversion Efficiency and Power Density 51.1.3 Switching Frequency and Impact of Soft-switching Technology 91.2 Concept of Soft-switching Technique 101.2.1 Soft-switching Types 111.2.2 Soft-switching Technique for Three-phase Converters 131.3 Applications of Soft-switching to Three-phase Converters 141.3.1 Renewable Energy and Power Generation 141.3.2 Energy Storage Systems 171.3.3 Distributed FACTS Devices 191.3.4 Uninterruptible Power Supply 191.3.5 Motor Drives 211.3.6 Fast EV Chargers 211.3.7 Power Supply 221.4 The Topics of This Book 22References 232 Basics of Soft-switching Three-phase Converters 272.1 Introduction 272.2 Switching Characteristics of Three-phase Converters 282.2.1 Control of Three-phase Converters 282.2.2 Switching Transient Process and Switching Loss 312.2.3 Diode Turn-off and Reverse Recovery 342.2.4 Stray Inductance on Switching Process 352.2.5 Snubber 382.3 Classification of Soft-switching Three-phase Converters 392.4 DC-side Resonance Converters 402.4.1 Resonant DC-link Converters 402.4.2 Active-clamped Resonant DC-link (ACRDCL) Converter 452.4.3 ZVS-SVM Active-clamping Three-phase Converter 462.4.3.1 Active-clamping DC–DC Converter 462.4.3.2 Active-clamping Three-phase Converter 522.5 AC-side Resonance Converters 542.5.1 Auxiliary Resonant Commutated Pole Converter 552.5.2 Coupled-inductor Zero Voltage-transition (ZVT) Inverter 592.5.3 Zero-current Transition (ZCT) Inverter 622.6 Soft-switching Inverter with TCM Control 622.7 Summary 66References 673 Soft-switching PWM Control for Active Clamped Three-phase Converters 713.1 Introduction 713.2 PWM of Three-phase Converters 723.3 Edge-aligned PWM 763.4 ZVS Active-clamping Converter with Edge-aligned PWM 773.4.1 Stage Analysis 783.4.2 ZVS Conditions 883.4.2.1 The First Resonant Stage 883.4.2.2 The Second Resonant Stage 913.4.2.3 Steady Conditions 933.4.3 Impact of PWM Scheme and Load on ZVS Condition 993.5 Control Diagram of the Converter with EA-PWM 1053.6 ZVS-SVM 1073.6.1 Vector Sequence 1093.6.2 ZVS-SVM Scheme 1113.6.3 Characteristics of the Converter with ZVS-SVM 1133.7 Summary 115References 116Part 2 ZVS-SVM Applied to Three-phase Rectifiers 1194 Three-phase Rectifier with Compound Active-clamping Circuit 1214.1 Introduction 1214.2 Operation Principle of CAC Rectifier 1224.2.1 Space Vector of Three-phase Grid Voltage 1224.2.2 Space Vector Modulation of Three-phase Converter 1244.2.3 Switching Scheme of CAC Rectifier 1264.3 Circuit Analysis 1344.3.1 Operation Stage Analysis 1344.3.2 Resonant Stages Analysis 1384.3.3 Steady State Analysis 1424.3.4 Soft-switching Condition 1444.3.5 Control Technique of Compound Active-clamping Three-phase Rectifier 1454.4 Prototype Design 1474.4.1 Specifications of a 40 kW Rectifier 1474.4.2 Parameter Design 1474.4.3 Experiment Platform and Testing Results 1514.5 Summary 156References 1565 Three-phase Rectifier with Minimum Voltage Active-clamping Circuit 1595.1 Introduction 1595.2 Operation Principle of MVAC Rectifier 1595.2.1 Space Vector Modulation of Three-phase Converter 1595.2.2 Switching Scheme of MVAC Rectifier 1625.3 Circuit Analysis of MVAC Rectifier 1685.3.1 Operation Stage Analysis 1685.3.2 Resonant Stages Analysis 1735.3.3 Steady State Analysis 1775.3.4 Soft-switching Condition 1795.3.5 Control Technique of Minimum Voltage Active-clamping Three-phase Rectifier 1825.4 Prototype Design 1845.4.1 Specifications of a 30 kW Rectifier 1845.4.2 Parameter Design 1845.4.3 Experiment Platform and Testing Results 1875.5 Summary 191References 192Part 3 ZVS-SVM Applied to Three-phase Grid Inverters 1936 Three-phase Grid Inverter with Minimum Voltage Active-clamping Circuit 1956.1 Introduction 1956.2 Operation Principle of MVAC Inverter 1956.2.1 Space Vector of Three-phase Grid Voltage 1956.2.2 Space Vector Modulation of Three-phase Inverter 1976.2.3 Switching Scheme of MVAC Inverter Under Unit Power Factor 2006.2.4 Generalized Space Vector Modulation Method of MVAC Inverter with Arbitrary Output 2066.3 Circuit Analysis 2106.3.1 Operation Stage Analysis 2106.3.2 Resonant Stages Analysis 2146.3.3 Steady-state Analysis 2176.3.4 Soft-switching Condition 2186.3.5 Control Technique of MVAC Inverter 2196.4 Design Prototype 2216.4.1 Specifications of a 30-kW Inverter 2216.4.2 Parameter Design 2226.4.3 Experiment Results 2256.5 Summary 230References 2307 Three-phase Inverter with Compound Active-clamping Circuit 2317.1 Introduction 2317.2 Scheme of ZVS-SVM 2327.2.1 Switch Commutations in Main Bridges of Three-phase Inverter 2327.2.2 Derivation of ZVS-SVM 2337.3 Circuit Analysis 2387.3.1 Operation Stage Analysis 2387.3.2 Resonant Stages Analysis 2437.3.3 Steady-state Analysis 2477.3.4 Soft-switching Condition 2507.3.5 Resonant Time Comparison 2507.4 Implementation of ZVS-SVM 2527.4.1 Regulation of Short Circuit Stage 2527.4.2 Implementation in Digital Controller 2527.4.3 Control Block Diagram with ZVS-SVM 2557.5 Prototype Design 2567.5.1 Specifications of a 30-kW Inverter 2567.5.2 Parameter Design 2567.5.2.1 Requirement of Diode Reverse Recovery Suppression 2567.5.2.2 Requirement of Voltage Stress 2577.5.2.3 Requirement of Reducing Turn-off Loss in Auxiliary Switch 2577.5.2.4 Requirement of Minimum Resonant Capacitance 2587.5.2.5 Requirement of Resonant Time 2587.5.3 Experiment Platform and Testing Results 2597.6 Summary 263References 2638 Loss Analysis and Optimization of a Zero-voltage-switching Inverter 2658.1 Introduction 2658.2 Basic Operation Principle of the CAC ZVS Inverter 2668.2.1 Operation Stage Analysis 2668.2.2 ZVS Condition Derivation 2728.3 Loss and Dimension Models 2768.3.1 Loss Model of IGBT Devices 2768.3.1.1 Conduction Loss of IGBT Devices 2768.3.1.2 Switching Loss of the IGBT Devices 2788.3.2 Loss and Dimension Models of Resonant Inductor 2818.3.3 Loss and Dimension Models of the Filter Inductor 2838.3.4 Dimension Model of Other Components 2848.3.4.1 Clamping Capacitor 2848.3.4.2 Heat Sink 2858.4 Parameters Optimization and Design Methodology 2888.4.1 Objective Function 2888.4.2 Constrained Conditions 2898.4.3 Optimization Design 2908.5 Prototype and Experimental Results 2928.6 Summary 295References 2969 Design of the Resonant Inductor 2979.1 Introduction 2979.2 Fundamental of Inductor 2979.3 Design Methodology 2999.3.1 Cross-section Area of the Core A c 3009.3.2 Window Area A e 3009.3.3 Area-product A p 3009.3.4 Turns of Winding N 3019.3.5 Length of the Air Gap l g 3019.3.6 Winding Loss P dc 3019.3.7 Core Loss P core 3029.3.8 Design Procedure 3039.4 Design Example 3039.4.1 Barrel Winding Discussion 3059.4.1.1 Winding Position Discussion 3069.4.1.2 Winding Thickness Discussion 3109.4.2 Flat Winding Discussion 3119.4.2.1 Different Structures Comparison 3119.4.2.2 Winding Position Discussion 3149.5 Design Verification 3179.5.1 Simulation Verification 3179.5.2 Experimental Verification 3189.6 Summary 320References 320Part 4 Impact of SiC Device on Soft-switching Grid Inverters 32110 Soft-switching SiC Three-phase Grid Inverter 32310.1 Introduction 32310.2 Soft-switching Three-phase Inverter 32410.2.1 SVM Scheme in Hard-switching Inverter 32410.2.2 ZVS-SVM Scheme in Soft-switching Inverter 32610.2.3 Operation Stages and ZVS Condition of Soft-switching Inverter 32610.2.3.1 Operation Stages Analysis 32610.2.3.2 ZVS Condition Derivation 32910.3 Efficiency Comparison of Hard-switching SiC Inverter and Soft-switching SiC Inverter 33410.3.1 Parameters Design of Soft-switching SiC Inverter 33410.3.1.1 AC Filter Inductor 33510.3.1.2 Resonant Parameters 33510.3.1.3 dc Filter Capacitor 33810.3.1.4 Clamping Capacitor 33810.3.1.5 Cores Selection 34110.3.1.6 Switching Loss Measurement 34210.3.2 Comparison of Two SiC Inverters 34410.3.2.1 Loss Distributions 34510.3.2.2 Efficiency Stiffness 34710.3.2.3 Passive Components Volumes 34810.3.3 Experimental Verification 34810.3.3.1 Efficiency Test 34810.3.3.2 Passive Components Volumes Comparison 35010.4 Design of Low Stray Inductance Layout in Soft-switching SiC Inverter 35010.4.1 Oscillation Model 35010.4.2 Design of Low Stray Inductance 7-in-1 SiC Power Module 35310.4.3 7-in-1 SiC Power Module Prototype and Testing Results 35610.4.3.1 Stray Inductance Measurement 35610.4.3.2 Voltage Stress Comparison 35810.5 Design of Low Loss Resonant Inductor in Soft-switching SiC Inverter 35910.5.1 Impact of Distributed Air Gap 35910.5.2 Optimal Flux Density Investigation 36010.5.3 Optimal Winding Foil Thickness Investigation 36010.5.4 Resonant Inductor Prototypes and Loss Measurement 36410.6 Summary 368References 36811 Soft-switching SiC Single-phase Grid Inverter with Active Power Decoupling 37111.1 Introduction 37111.1.1 Modulation Methods for Single-phase Inverter 37111.1.2 APD in Single-phase Grid Inverter 37211.2 Operation Principle 37611.2.1 Topology and Switching Scheme 37611.2.2 Stage Analysis 37911.3 Circuit Analysis 38511.3.1 Resonant Stages Analysis 38511.3.2 Steady-state Analysis 38711.3.3 Soft-switching Condition 38811.3.4 Short Circuit Current 38811.4 Design Prototype 39011.4.1 Rated Parameters of a 1.5-kW Inverter 39011.4.2 Parameter Design 39111.4.3 Experimental Platform and Testing Results 39311.5 Summary 398References 39812 Soft-switching SiC Three-phase Four-wire Back-to-back Converter 40112.1 Introduction 40112.2 Operation Principle 40212.2.1 Commutations Analysis 40312.2.2 Operation Scheme 40312.2.3 Stage Analysis 40512.3 Circuit Analysis 41412.3.1 Resonant Stage Analysis 41412.3.2 Steady State Analysis 41712.3.3 ZVS Condition 42212.4 Design Prototype 42312.4.1 Parameters Design 42312.4.2 Loss Analysis 42712.4.3 Experimental Results 43112.5 Summary 440References 440Appendix 441A.1 Basic of SVM 441A.2 Switching Patterns of SVM 12 446A.3 Switching Patterns of ZVS-SVM 448A.4 Inverter Loss Models 450A.4.1 Loss Model of Hard-switching Three-phase Grid Inverter 450A.4.1.1 Conducting Loss 450A.4.1.2 Switching Loss 453A.4.1.3 AC Filter Inductor Loss and Volume Estimations 454A.4.2 Loss Model of Soft-switching Three-phase Grid Inverter 456A.4.2.1 Loss in Main Switches 456A.4.2.2 Loss in Auxiliary Switch 458A.4.2.3 Loss and Volume of Filter Inductor and Resonant Inductor 459A.5 AC Filter Inductance Calculation 459A.6 DC Filter Capacitance Calculation 462Index 469