Voltage-Sourced Converters in Power Systems: Modeling, Control, and Applications

VOLTAGE-SOURCED CONVERTERS IN POWER SYSTEMS......Page 5
CONTENTS......Page 9
PREFACE......Page 17
ACKNOWLEDGMENTS......Page 19
ACRONYMS......Page 21
1.2 Power-Electronic Converters and Converter Systems......Page 23
1.3 Applications of Electronic Converters in Power Systems......Page 25
1.4 Power-Electronic Switches......Page 26
1.4.1 Switch Classification......Page 27
1.5.1 Classification Based on Commutation Process......Page 30
1.5.2 Classification Based on Terminal Voltage and Current Waveforms......Page 31
1.7 Basic Configurations......Page 32
1.7.1 Multimodule VSC Systems......Page 33
1.7.2 Multilevel VSC Systems......Page 36
1.8 Scope of the Book......Page 42
PART I FUNDAMENTALS......Page 43
2.2 Converter Structure......Page 45
2.3.1 Pulse-Width Modulation (PWM)......Page 47
2.3.2 Converter Waveforms......Page 48
2.4 Converter Switched Model......Page 49
2.5 Converter Averaged Model......Page 54
2.6.1 Analysis of Nonideal Half-Bridge Converter: Positive AC-Side Current......Page 60
2.6.2 Analysis of Nonideal Converter: Negative AC-Side Current......Page 65
2.6.3 Averaged Model of Nonideal Half-Bridge Converter......Page 67
3.2 AC-Side Control Model of Half-Bridge Converter......Page 70
3.3 Control of Half-Bridge Converter......Page 72
3.4.1 Impact on Start-Up Transient......Page 75
3.4.2 Impact on Dynamic Coupling Between Converter System and AC System......Page 76
3.4.3 Impact on Disturbance Rejection Capability......Page 79
3.5 Sinusoidal Command Following......Page 81
4.1 Introduction......Page 91
4.2.1 Definition of Space Phasor......Page 92
4.2.2 Changing the Amplitude and Phase Angle of a Three-phase Signal......Page 95
4.2.3 Generating a Controllable-Amplitude/Controllable-Frequency Three-Phase Signal......Page 100
4.2.4 Space-Phasor Representation of Harmonics......Page 103
4.3 Space-Phasor Representation of Three-Phase Systems......Page 104
4.3.1 Decoupled Symmetrical Three-Phase Systems......Page 105
4.3.2 Coupled Symmetrical Three-Phase Systems......Page 109
4.4 Power in Three-Wire Three-Phase Systems......Page 110
4.5.1 αβ-Frame Representation of a Space Phasor......Page 113
4.5.2 Realization of Signal Generators/Conditioners in αβ-Frame......Page 116
4.5.3 Formulation of Power in αβ-Frame......Page 117
4.5.4 Control in αβ-Frame......Page 118
4.5.5 Representation of Systems in αβ-Frame......Page 120
4.6.1 dq-Frame Representation of a Space Phasor......Page 123
4.6.3 Control in dq-Frame......Page 127
4.6.4 Representation of Systems in dq-Frame......Page 129
5.2.1 Circuit Structure......Page 137
5.2.2 Principles of Operation......Page 138
5.2.3 Power Loss of Nonideal Two-Level VSC......Page 140
5.3.1 Averaged Model of Two-Level VSC......Page 141
5.3.2 Model of Two-Level VSC in αβ-Frame......Page 143
5.3.3 Model and Control of Two-Level VSC in dq-Frame......Page 146
5.4 Classification of VSC Systems......Page 147
6.1 Introduction......Page 149
6.2.1 Generating Positive AC-Side Voltages......Page 150
6.2.2 Generating Negative AC-Side Voltages......Page 151
6.3 PWM Scheme For Three-Level Half-Bridge NPC......Page 152
6.4.2 Switched DC-Side Terminal Currents......Page 155
6.5.2 Averaged DC-Side Terminal Currents......Page 157
6.6.2 Principles of Operation......Page 158
6.6.3 Midpoint Current......Page 160
6.6.4 Three-Level NPC with Impressed DC-Side Voltages......Page 165
6.7 Three-Level NPC with Capacitive DC-Side Voltage Divider......Page 166
6.7.1 Partial DC-Side Voltage Drift Phenomenon......Page 167
6.7.2 DC-Side Voltage Equalization......Page 168
6.7.3 Derivation of DC-Side Currents......Page 174
6.7.4 Unified Models of Three-Level NPC and Two-Level VSC......Page 175
6.7.5 Impact of DC Capacitors Voltage Ripple on AC-Side Harmonics......Page 177
7.2 Structure of Grid-Imposed Frequency VSC System......Page 182
7.3 Real-/Reactive-Power Controller......Page 183
7.3.1 Current-Mode Versus Voltage-Mode Control......Page 184
7.3.2 Dynamic Model of Real-/Reactive-Power Controller......Page 185
7.3.3 Current-Mode Control of Real-/Reactive-Power Controller......Page 187
7.3.4 Selection of DC-Bus Voltage Level......Page 190
7.3.5 Trade-Offs and Practical Considerations......Page 195
7.3.6 PWM with Third-Harmonic Injection......Page 196
7.4 Real-/Reactive-Power Controller Based on Three-Level NPC......Page 203
7.4.1 Midpoint Current of Three-level NPC Based on Third-Harmonic Injected PWM......Page 210
7.5 Controlled DC-Voltage Power Port......Page 211
7.5.1 Model of Controlled DC-Voltage Power Port......Page 213
7.5.2 DC-Bus Voltage Control in Controlled DC-Voltage Power Port......Page 217
7.5.3 Simplified and Accurate Models......Page 222
8.1 Introduction......Page 226
8.2 Structure of Grid-Imposed Frequency VSC System......Page 227
8.3.1 Current-Mode Versus Voltage-Mode Control......Page 228
8.3.3 Dynamic Model of Real-/Reactive-Power Controller......Page 230
8.3.4 Phase-Locked Loop (PLL)......Page 233
8.3.5 Compensator Design for PLL......Page 235
8.4 Current-Mode Control of Real-/Reactive-Power Controller......Page 239
8.4.1 VSC Current Control......Page 241
8.4.2 Selection of DC-Bus Voltage Level......Page 246
8.4.3 AC-Side Equivalent Circuit......Page 248
8.4.4 PWM with Third-Harmonic Injection......Page 253
8.5 Real-/Reactive-Power Controller Based on Three-Level NPC......Page 254
8.6 Controlled DC-Voltage Power Port......Page 256
8.6.1 Model of Controlled DC-Voltage Power Port......Page 257
8.6.2 Control of Controlled DC-Voltage Power Port......Page 259
8.6.3 Simplified and Accurate Models......Page 264
9.1 Introduction......Page 267
9.2 Structure of Controlled-Frequency VSC System......Page 268
9.3 Model of Controlled-Frequency VSC System......Page 269
9.4 Voltage Control......Page 275
9.4.1 Autonomous Operation......Page 284
10.2 Structure of Variable-Frequency VSC System......Page 292
10.3 Control of Variable-Frequency VSC System......Page 295
10.3.1 Asynchronous Machine......Page 296
10.3.2 Doubly-Fed Asynchronous Machine......Page 310
10.3.3 Permanent-Magnet Synchronous Machine......Page 329
PART II APPLICATIONS......Page 333
11.2 Controlled DC-Voltage Power Port......Page 335
11.3 STATCOM Structure......Page 336
11.4.1 Large-Signal Model of PCC Voltage Dynamics......Page 337
11.4.2 Small-Signal Model of PCC Voltage Dynamics......Page 340
11.4.3 Steady-State Operating Point......Page 342
11.5 Approximate Model of PCC Voltage Dynamics......Page 343
11.6 STATCOM Control......Page 344
11.8 Model Evaluation......Page 346
12.2 HVDC System Structure......Page 356
12.3.1 Grid and Interface Transformer Models......Page 358
12.3.2 Back-to-Back Converter System Model......Page 360
12.4.1 Phase-Locked Loop (PLL)......Page 364
12.4.2 dq-Frame Current-Control Scheme......Page 367
12.4.3 PWM Gating Signal Generator......Page 370
12.4.4 Partial DC-Side Voltage Equalization......Page 371
12.4.5 Power Flow Control......Page 372
12.4.6 DC-Bus Voltage Regulation......Page 373
12.5 HVDC System Performance Under an Asymmetrical Fault......Page 375
12.5.1 PCC Voltage Under an Asymmetrical Fault......Page 376
12.5.2 Performance of PLL Under an Asymmetrical Fault......Page 379
12.5.3 Performance of dq-Frame Current-Control Scheme Under an Asymmetrical Fault......Page 380
12.5.4 Dynamics of DC-Bus Voltage Under an Asymmetrical Fault......Page 382
12.5.5 Generation of Low-Order Harmonics Under an Asymmetrical Fault......Page 387
12.5.6 Steady-State Power-Flow Under an Asymmetrical Fault......Page 391
12.5.7 DC-Bus Voltage Control Under an Asymmetrical Fault......Page 393
13.2.1 Constant-Speed Wind-Power Systems......Page 407
13.2.2 Variable-Speed Wind-Power Systems......Page 408
13.3 Wind Turbine Characteristics......Page 410
13.4 Maximum Power Extraction from A Variable-Speed Wind-Power System......Page 412
13.5.1 Structure of the Doubly-Fed Asynchronous Machine-Based Wind-Power System......Page 415
13.5.2 Machine Torque Control by Variable-Frequency VSC System......Page 417
13.5.3 DC-Bus Voltage Regulation by Controlled DC-Voltage Power Port......Page 419
13.5.4 Compensator Design for Controlled DC-Voltage Power Port......Page 423
A.2 Structure of Symmetrical Three-Phase Machine......Page 435
A.3 Machine Electrical Model......Page 436
A.3.2 Stator Flux Space Phasor......Page 437
A.3.3 Rotor Flux Space Phasor......Page 439
A.4.1 Machine Dynamic Equivalent Circuit......Page 440
A.4.2 Machine Steady-State Equivalent Circuit......Page 442
A.5.1 PMSM Electrical Model......Page 443
A.5.2 PMSM Steady-State Equivalent Circuit......Page 446
B.1.2 Base Values for DC-Side Quantities......Page 448
REFERENCES......Page 453
INDEX......Page 461