Sneak Circuits of Power Electronic Converters

Bo Zhang South China University of Technology, P. R. China.Dongyuan Qiu South China University of Technology, P. R. China.

• About the Authors xiPreface xiiiAcknowledgments xvii1 Sneak Circuit and Power Electronic Systems 11.1 Reliability of Power Electronic Systems 11.2 Sneak Circuit 21.2.1 Definition of Sneak Circuit 21.2.2 Examples of Sneak Circuits 31.2.3 Basic Causes of Sneak Circuit 91.3 Sneak Circuit Analysis 101.3.1 Definition of Sneak Circuit Analysis 101.3.2 History of Sneak Circuit Analysis 101.3.3 Methods of Sneak Circuit Analysis 111.3.4 Benefits of Sneak Circuit Analysis 121.3.5 Relationship between Sneak Circuit Analysis and other Safety Techniques 131.4 Power Electronic System and Sneak Circuit Analysis 141.5 Arrangement of this Book 15References 15Part I SNEAK CIRCUIT PHENOMENA2 Sneak Circuits of Resonant Switched Capacitor Converters 192.1 Introduction 192.2 Sneak Circuits of Basic RSC Converter 192.2.1 Sneak Circuits of Basic Step-Down RSC Converter 202.2.2 Sneak Circuits of Basic Step-Up RSC Converter 272.2.3 Sneak Circuits of Basic Inverting RSC Converter 342.2.4 Sneak Circuit Performance of Basic RSC Converters 372.3 Sneak Circuits of High-Order RSC Converter 372.3.1 Sneak Circuits of High-Order Step-Down RSC Converter 382.3.2 Sneak Circuits of High-Order Step-Up RSC Converter 472.4 Summary 57References 573 Sneak Circuits of DC-DC Converters 593.1 Introduction 593.2 Buck Converter 593.2.1 CCM of Buck Converter 593.2.2 DCM of Buck Converter 613.2.3 Operating Conditions of Buck Converter 623.3 Boost Converter 633.3.1 CCM of Boost Converter 633.3.2 DCM of Boost Converter 653.3.3 Operating Conditions of Boost Converter 663.4 Buck-Boost Converter 673.4.1 CCM of Buck-Boost Converter 673.4.2 DCM of Buck-Boost Converter 683.4.3 Operating Conditions of Buck-Boost Converter 703.5 Sneak Circuit Conditions of Buck, Boost, and Buck-Boost Converters 713.6 Cúk Converter 713.6.1 Normal Operating Mode of Cúk Converter 713.6.2 Sneak Circuit Phenomena of Cúk Converter 743.6.3 Experimental Verification of Cúk Converter 813.7 Sepic Converter 843.7.1 Normal Operating Mode of Sepic Converter 843.7.2 Sneak Circuit Phenomena of Sepic Converter 893.7.3 Experimental Verification of Sepic Converter 913.8 Zeta Converter 913.8.1 Normal Operating Mode of Zeta Converter 943.8.2 Sneak Circuit Phenomena of Zeta Converter 983.8.3 Experimental Verification of Zeta Converter 1003.9 Sneak Circuit Conditions of Cúk, Sepic, and Zeta Converters 1023.10 Summary 103References 1034 Sneak Circuits of Soft-Switching Converters 1054.1 Introduction 1054.2 Sneak Circuits of Full-Bridge ZVS PWM Converter 1054.2.1 Normal Operating Mode of FB ZVS PWM Converter 1064.2.2 Zero Voltage Switching Conditions of FB ZVS PWM Converter 1124.2.3 Sneak Circuit Phenomena of FB ZVS PWM Converter 1124.2.4 Operating Conditions of FB ZVS PWM Converter 1184.2.5 Experimental Verification of FB ZVS PWM Converter 1194.3 Sneak Circuits of Buck ZVS Multi-Resonant Converter 1224.3.1 Normal Operating Mode of Buck ZVS MR Converter 1234.3.2 Sneak Circuit Phenomenon of Buck ZVS MR Converter 1264.3.3 Simulation Verification of Buck ZVS MR Converter 1284.4 Sneak Circuits of Buck ZVT PWM Converter 1284.4.1 Normal Operating Mode of Buck ZVT PWM Converter 1304.4.2 Sneak Circuit Phenomenon of Buck ZVT PWM Converter 1334.4.3 Simulation Verification of Buck ZVT PWM Converter 1364.5 Summary 137References 1375 Sneak Circuits of other Power Electronic Converters 1395.1 Introduction 1395.2 Sneak Circuits of Z-Source Inverter 1395.2.1 Operating Principles of Z-Source Inverter 1405.2.2 Sneak Circuits of Z-Source Inverter 1445.2.3 Simulation Verification of Z-Source Inverter 1475.3 Sneak Circuits of Synchronous DC-DC Converters 1485.3.1 Equivalent Circuit of Synchronous Buck Converter 1495.3.2 Normal Operating Principle of Synchronous Buck Converter 1505.3.3 Sneak Circuits of Synchronous Buck Converter 1525.3.4 Sneak Circuit Condition of Synchronous Buck Converter 1545.3.5 Simulation Verification of Synchronous Buck Converter 1555.4 Summary 156References 157Part II SNEAK CIRCUIT ANALYSIS METHODS6 Sneak Circuit Path Analysis Method for Power Electronic Converters 1616.1 Introduction 1616.2 Basic Concepts 1616.2.1 Directed Graph 1616.2.2 Adjacency Matrix 1626.2.3 Connection Matrix 1646.2.4 Switching Function and Transfer Matrix 1666.2.5 Switching Network and Switching Boolean Matrix 1676.3 Sneak Circuit Path Analysis Based on Adjacency Matrix 1696.3.1 Directed Graph and Adjacency Matrix of Power Electronic Converter 1696.3.2 Searching Algorithms 1706.3.3 Current Path Search in Power Electronic Converter 1736.3.4 Sneak Circuit Path Judgment in Power Electronic Converter 1746.3.5 Sneak Circuit Path Analysis Software Based on Adjacency Matrix 1746.4 Sneak Circuit Path Analysis Based on Connection Matrix 1786.4.1 Generalized Connection Matrix of Power Electronic Converter 1786.4.2 Identification of False Current Loop 1796.4.3 Example 1816.4.4 Sneak Circuit Loop Analysis Software Based on Connection Matrix 1846.5 Sneak Circuit Path Analysis Based on Switching Boolean Matrix 1846.5.1 Switching Boolean Matrix of Power Electronic Converter 1846.5.2 Invalid Switching Vector Criteria 1906.5.3 Example 1916.5.4 Sneak Circuit Path Analysis Software Based on Switching Boolean Matrix 1946.6 Comparison of Three Sneak Circuit Path Analysis Methods 1966.7 Summary 197References 1977 Sneak Circuit Mode Analysis Method for Power Electronic Converters 1997.1 Introduction 1997.2 Mesh Combination Analytical Method 2007.2.1 Mesh and Connecting Piece 2007.2.2 Basic Graph Algorithms 2007.2.3 Mesh Combination Method 2017.3 Sneak Operating Unit Analytical Method 2047.3.1 Mesh Combination Results of Cúk Converter 2047.3.2 Effective Operating Units of Cúk Converter 2057.3.3 Sneak Operating Units of Cúk Converter 2097.4 Sneak Circuit Operating Mode Analytical Method 2107.4.1 Sneak Circuit Phenomenon of Cúk Converter Caused by Variations of Topology 2117.4.2 Sneak Circuit Phenomenon of Cúk Converter Caused by Changing of Current Direction 2127.5 Results of Sneak Circuit Mode Analysis Method on Cúk Converter 2167.6 Summary 219References 220Part III ELIMINATION AND APPLICATION OF SNEAK CIRCUITS8 Elimination of Sneak Circuits in Power Electronic Converters 2238.1 Introduction 2238.2 Sneak Circuit Elimination for RSC Converters 2248.2.1 Parameter Design Principle 2248.2.2 Topology Improvement Scheme 2258.2.3 Examples 2278.3 Sneak Circuit Elimination for Z-Source Inverter 2308.3.1 Restricted Operating Conditions 2308.3.2 Topology Improvement 2308.4 Sneak Circuit Elimination for Buck ZVT PWM Converter 2338.4.1 Topology Improving Scheme I 2348.4.2 Topology Improving Scheme II 2368.4.3 Simulation Verification 2408.5 Summary 240References 2419 Application of Sneak Circuits in Power Electronic Converters 2439.1 Introduction 2439.2 Improvement of Power Electronic Converter Based on Sneak Circuits 2439.2.1 Operating Principle of Boost ZCT PWM Converter 2439.2.2 Sneak Circuit Paths of Boost ZCT PWM Converter 2479.2.3 The Improved Control Method of Boost ZCT PWM Converter 2489.3 Reconstruction of Power Electronic Converter Based on Sneak Circuits 2529.3.1 Structure of Boost ZCT PWM Converter 2539.3.2 Performance of the Modified Boost ZCT PWM Converter 2539.4 New Functions of Power Electronic Converter Based on Sneak Circuits 2589.4.1 PFC Principle of Cúk Converter 2589.4.2 PFC Implementation of Cúk Converter 2629.5 Fault Analysis of Power Electronic Converter Based on Sneak Circuits 2649.5.1 Adjacency Matrix of Diode-Clamped Three-Level HB Inverter 2659.5.2 Electrical Characteristics of Diode-Clamped Three-Level HB Inverter 2679.5.3 Failure Criterion of Diode-Clamped Three-Level HB Inverter 2689.5.4 Simulation Verification of Diode-Clamped Three-Level HB Inverter 2719.6 Summary 272References 274Index 277