A comprehensive look at DC-DC converters and advanced power converter topologies for all skills levels
As it can be rare for source voltage to meet the requirements of a Direct Current (DC) load, DC-DC converters are essential to access service. DC-DC power converters employ power semiconductor devices (like MOSFETs and IGBTs) as switches and passive elements such as capacitors, inductors, and transformers to alter the voltage provided by a DC source into the necessary DC voltage as is required by a DC load. This source can be a battery, solar panels, fuel cells, or a DC bus voltage fed by rectified AC utility voltage. As the many components of DC-DC converters can be differently arranged into circuit structures called topologies, there are as many possible circuit topologies as there are possible combinations of circuit elements.
Focusing on DC-DC switch-mode power converters ranging from 50 W to 10kW, DC-DC Converter Topologies provides a survey of all converter topology types within this power range. General principles are described for each topology type using a representative converter as an example. Variations that can be found that differ from the example are then examined, with a helpful discussion of comparisons when relevant. A broad range of topics is covered within the book, from simple, low-power converters to complex, high-power converters and everywhere in between.
DC-DC Converter Topologies readers will also find: - A detailed discussion of four key DC-DC converter topologies - Description of isolated two-switch pulse-width modulated (PWM) topologies including push-pull, half-bridge, and interleaved converters - An exploration of high-gain converters such as coupled inductors, voltage multipliers, and switched capacitor converters
This book provides the tools so that a non-expert will be equipped to deal with the vast array of DC-DC converters that presently exist. As such, DC-DC Converter Topologies is a useful reference for electrical engineers, professors, and graduate students studying in the field.
Table of Contents
About the Author xv
Preface xvi
1 Basic Concepts 1
1.1 Linear Voltage Regulators 1
1.2 Switch-Mode Power Supply Fundamentals 3
1.2.1 Buck Converter 3
1.2.2 Boost Converter 5
1.2.3 Buck-Boost Converter 6
1.3 PWM Converters with Voltage Step-Up and Step-Down Capabilities 8
1.3.1 Cuk Converter 8
1.3.2 Single-Ended Primary Inductance Converter (SEPIC) 9
1.3.3 Zeta Converter 10
1.3.4 Comparison Between Converters with Voltage Step-Up and Step-Down Capabilities 10
1.4 Interleaved Converters 12
1.5 Semiconductor Devices 14
1.5.1 Silicon Diodes 14
1.5.2 Silicon MOSFETs 15
1.5.3 Silicon IGBTs 17
1.5.4 Gate Drive Circuits 18
1.5.5 Wide Bandgap Devices 19
1.6 Snubbers 21
1.7 Conclusion 23
References 23
2 Non-isolated Zero-voltage Switching PWM Converters 25
2.1 Basic ZVS Principles for MOSFETS 26
2.2 ZVS-PWM Quasi-Square-Wave DC-DC Converters 28
2.3 ZVS-PWM DC-DC Converters with Auxiliary Circuits 30
2.3.1 Nonresonant Auxiliary Circuits 31
2.3.2 Resonant Auxiliary Circuits 37
2.3.3 Dual Auxiliary Circuits 40
2.4 Miscellaneous Considerations 42
2.4.1 Application-Specific ZVS-PWM Converters 42
2.4.2 ZVS-PWM Techniques in Converters with Wide Bandgap Devices 43
2.5 Conclusion 44
References 45
3 Non-isolated Zero-current Switching PWM Converters 46
3.1 ZCS-PWM Converters with Series-Resonant Auxiliary Circuits 47
3.1.1 ZCS-PWM Converter with Fully Resonant Auxiliary Circuit 48
3.1.2 ZCS-PWM Converter with Modified Resonant Auxiliary Circuit 51
3.1.3 Converter with Hard-Switching Auxiliary Circuit 51
3.2 ZCS-PWM Boost Converters with Conventional PWM Converter Main Switch Current Stress 52
3.2.1 ZCS-PWM Converter with Series Boost Diode 52
3.2.2 ZCS-PWM Converter with Output Resonance 54
3.2.3 ZCT-PWM Converters with Parallel Auxiliary Circuit 55
3.3 ZVSZCS-PWM Boost Converters 57
3.4 Conclusion 60
References 61
4 Basic Isolated Converters 63
4.1 Transformer Models 64
4.2 Flyback Converter 64
4.3 Forward Converter 67
4.4 Variations on the Forward Converter 69
4.4.1 Forward Converter with RCD Snubber 69
4.4.2 Forward Converter with LCDD Snubber 70
4.4.3 Forward Converter with Regenerative Energy Snubber 71
4.5 Basic Two-Switch Isolated Converters 72
4.5.1 Two-Switch Forward Converter 72
4.5.2 Push-Pull Converter 74
4.5.3 Half-Bridge Converter 76
4.6 Full-Bridge Converter 77
4.7 Conclusion 80
Reference 81
5 Secondary-side Implementations in Isolated DC-DC Converters 82
5.1 Synchronous Rectifiers 82
5.2 Current Doublers 90
5.3 Multi-Output Converters 94
5.4 Conclusion 98
References 99
6 Soft-switching Forward and Flyback Converters 102
6.1 Forward Converters with Resonant Reset 103
6.2 Active Clamp Converter 104
6.2.1 Modes of Operation 106
6.2.2 Design Considerations 110
6.2.3 Active Clamp Flyback Converter 114
6.3 Alternatives to the Active Clamp Converter 115
6.3.1 Forward Converters 115
6.3.2 Flyback Converters 117
6.3.3 Converters with Regenerative Energy Snubber 119
6.4 Conclusion 120
References 121
7 The ZVS-PWM Full-bridge Converter 123
7.1 DC-DC PWM Full-Bridge Converter with Basic PWM Control 124
7.2 ZVS-PWM Full-Bridge Converter with Phase-Shift PWM 125
7.3 Issues Related to the Operation of ZVS-PWM PWM Full-Bridge Converter 131
7.3.1 ZVS Operation 131
7.3.2 Duty-Cycle Loss 134
7.3.3 Voltage Ringing 136
7.4 ZVS-PWM PWM Full-Bridge Converter Design Considerations 137
7.5 Light Load Operation and Hybrid PWM 140
7.6 ZVS PWM Full-Bridge Converters with Wide Bandgap Devices 140
7.7 Conclusion 141
References 142
8 Variations on the Conventional Zero-voltage-Switching DC-DC PWM Full-bridge Converter 144
8.1 Modified ZVS-PWM DC-DC Full-Bridge Converter with Saturable Reactors 145
8.1.1 Modified ZVS-PWM-FB Converter with Primary-Side Saturable Reactor 145
8.1.2 Modified ZVS-PWM-FB Converters with Secondary-Side Saturable Reactors 146
8.2 Modified ZVS-PWM-FB Converters with Passive Series Auxiliary Circuits 149
8.3 ZVS-PWM-FB Converters with Passive Parallel Auxiliary Circuits 151
8.4 ZVS-PWM-FB Converters with Passive Parallel Auxiliary Circuits with a Transformer 153
8.4.1 ZVS-PWM-FB Converter with a Passive Auxiliary Series Auxiliary Circuit with a Transformer 153
8.4.2 ZVS-PWM-FB Converters with Passive Parallel Auxiliary Circuits and Reduced Output Current Ripple 156
8.5 ZVS-PWM-FB Converters with Active Auxiliary Circuits 157
8.6 ZVS-PWM-FB Converter with a Single Active Auxiliary Circuit 161
8.7 ZVS-PWM-FB Converters Based on Dual Half-Bridge Converters 164
8.8 ZVS-PWM-FB Converters with Modified Secondary-Side Circuits for ZVS Operation 167
8.9 Conclusion 170
References 172
9 Zero-voltage-zero-current-switching DC-DC Full-bridge PWM Converters 174
9.1 Fundamental ZVZCS-PWM DC-DC Full-Bridge Converter 175
9.2 ZVZCS-PWM DC-DC Full-Bridge Converters with Secondary Auxiliary Circuit 183
9.3 Variations of ZVZCS Converters for Full ZVS or Full ZCS Operation 193
9.3.1 ZVS Converters 193
9.3.2 ZCS Converters 194
9.3.3 ZVS-PWM Converters Based on ZVZCS-PWM Converters with Triangular Primary Current Waveform 195
9.4 Conclusion 198
References 199
10 Isolated Current-fed DC-DC PWM Converters 201
10.1 Basic Current-Fed Push-Pull Converter 203
10.2 Basic Two-Inductor Current-Fed Converter 204
10.3 Modified Two-Inductor Current-Fed Converter with Auxiliary Transformer 207
10.4 Basic Current-Fed Full-Bridge Topology 210
10.5 Current-Fed DC-DC Full-Bridge Converters with Blocking Diodes 212
10.6 Current-Fed DC-DC Full-Bridge Converters without Blocking Diodes 215
10.6.1 ZVS-PWM Active-Clamp Full-Bridge Converter 215
10.6.2 ZCS-PWM Full-Bridge Converter with Parallel Auxiliary Circuit 217
10.7 Conclusion 219
References 220
11 Resonant Converters Part I - Fundamentals 222
11.1 Resonant Power Conversion Fundamentals 223
11.2 Fundamental Resonant DC-DC Converters 228
11.2.1 Resonant Converter Analysis Using First Harmonic Approximation Method 231
11.2.2 Series-Resonant Converter vs Parallel-Resonant Converter 234
11.2.3 Series-Parallel-Resonant Converter 236
11.3 LLC Resonant Converter 238
11.4 Other Resonant DC-DC Converters 241
11.5 Conclusion 245
References 246
12 Resonant Converters Part II - PWM Controlled, Quasi-resonant, and Ultrahigh-frequency Converters 248
12.1 Fixed Frequency Resonant Converters 249
12.1.1 Full-Bridge Resonant Converters Operated with Phase-Shift PWM 249
12.1.2 Resonant Converters Operated with Asymmetrical PWM 252
12.1.3 Adding Variable Resonant Components 257
12.2 Quasi-Resonant Converters 258
12.2.1 Resonant Pulse Converters 264
12.2.2 Fixed-Frequency Quasi-Resonant Converters 265
12.3 Ultrahigh Frequency Converters 266
12.3.1 Multi-Resonant Converters 267
12.3.2 Ultrahigh Frequency Converters Based on Radio-Frequency Amplifier Circuits 268
12.3.3 Ultrahigh Frequency Converters with Air-Core Inductors 269
12.4 Conclusion 270
References 270
13 Three-level DC-DC Converters 273
13.1 Fundamental Three-Level DC-DC PWM Converters 274
13.1.1 Neutral-Point-Clamped Three-Level DC-DC Converter 274
13.1.2 Flying Capacitor Three-Level DC-DC Converter 280
13.1.3 Three-Level DC-DC Converter with Series Blocking Capacitor 286
13.1.4 Comparison of Fundamental Three-Level DC-DC Converter Topologies 291
13.2 Modified Three-Level DC-DC Converters 292
13.2.1 ZVS Three-Level Converters 292
13.2.2 ZVZCS Three-Level Converters 298
13.3 Stacked Converters 302
13.4 Three-Level DC-DC Converters in Applications with Low and Conventional DC Bus Voltage 306
13.5 Conclusion 307
References 308
14 High Gain Converters 311
14.1 Voltage Multiplier Circuits 312
14.1.1 Output Voltage Multiplier Circuits 312
14.1.2 Internal Voltage Multiplier Circuits 316
14.2 Switched Capacitor Converters 318
14.3 Voltage-Lift and Switched Inductor Converters 321
14.4 Cascaded and Quadratic Converters 326
14.5 Converters with Magnetic Coupling 328
14.5.1 Tapped Inductor Converters 328
14.5.2 Coupled Inductor Converters 329
14.5.3 Transformer-Coupled Converters 331
14.6 Multi-Level and Interleaved Converters 331
14.6.1 Multi-Level Converters 332
14.6.2 Interleaved Converters 335
14.7 Hybrid Converters and Converter Selection 336
14.8 Conclusion 340
References 340
15 Three-phase DC-DC Converters 343
15.1 Fundamental Voltage-Fed Three-Phase DC-DC PWM Converter 344
15.1.1 Basic Operating Principles with Symmetrical PWM 344
15.1.2 Operation with Asymmetrical PWM 346
15.1.3 Modified Output Section with Three Output Diodes 347
15.2 Resonant Converters 349
15.2.1 Parallel Resonant Converter Based on the Fundamental Converter 349
15.2.2 Three-Phase Series-Parallel Resonant Converters with Variable and Fixed Switching Frequency Operation 350
15.3 Three-Phase Current-Fed DC-DC PWM Converters 351
15.3.1 Three-Phase ZVS Active Clamp Converter 351
15.3.2 Three-Phase ZCS Converter 353
15.4 Higher-Power Three-Phase DC-DC Converters 355
15.4.1 High-Power Converter with Three Single-Phase PWM Full-Bridges 355
15.4.2 High-Power Converter with Three Single-Phase Resonant Full-Bridges 356
15.5 Three-Switch Three-Phase DC-DC PWM Converters 356
15.5.1 Three-Phase Push-Pull Converter 357
15.5.2 ZVS Active Clamp Converter 359
15.5.3 ZCS Converter with Secondary-Side Resonance 361
15.5.4 Converter with Mini-Flyback Snubber 362
15.6 Miscellaneous Three-Phase Converter Examples 363
15.6.1 Three-Phase DC-DC Multi-Level Converter 363
15.6.2 Three-Phase DC-DC High-Gain Converter 364
15.7 Three-Phase Transformer Implementations 365
15.8 Conclusion 367
References 367
16 Bidirectional and Dual Active Bridge Converters 369
16.1 Basic Non-Isolated Bidirectional Converters 370
16.2 ZVS Operation of the Fundamental Buck-Boost Bidirectional Converter 372
16.2.1 Bidirectional Quasi-Square Wave Converter 372
16.2.2 Four-Switch Buck-Boost Converter 373
16.2.3 Active Auxiliary Circuits 375
16.3 Bidirectional Converter Topologies with Transformer Isolation 377
16.4 Dual Active Bridge Converters 381
16.4.1 Dual Active Bridge Half-Bridge Converter 381
16.4.2 Dual Active Bridge PWM Full-Bridge Converters 383
16.5 Conclusion 387
References 388
17 Miscellaneous DC-DC Converters 391
17.1 Z-Source Converters 392
17.2 Low Voltage Gain Converters for Voltage Regulator Modules 396
17.3 T-Type Converters 401
17.4 Multi-Port Converters 405
17.4.1 Non-Isolated Multi-Input Converters 406
17.4.2 Isolated Multi-Port Converters 408
17.5 Conclusion 412
References 413
Appendix 415
Index 427
