Modeling and Modern Control of Wind Power

An essential reference to the modeling techniques of wind turbine systems for the application of advanced control methods

This book covers the modeling of wind power and application of modern control methods to the wind power control—specifically the models of type 3 and type 4 wind turbines. The modeling aspects will help readers to streamline the wind turbine and wind power plant modeling, and reduce the burden of power system simulations to investigate the impact of wind power on power systems. The use of modern control methods will help technology development, especially from the perspective of manufactures. 

Chapter coverage includes: status of wind power development, grid code requirements for wind power integration; modeling and control of doubly fed induction generator (DFIG) wind turbine generator (WTG); optimal control strategy for load reduction of full scale converter (FSC) WTG; clustering based WTG model linearization; adaptive control of wind turbines for maximum power point tracking (MPPT); distributed model predictive active power control of wind power plants and energy storage systems; model predictive voltage control of wind power plants; control of wind power plant clusters; and fault ride-through capability enhancement of VSC HVDC connected offshore wind power plants. Modeling and Modern Control of Wind Power also features tables, illustrations, case studies, and an appendix showing a selection of typical test systems and the code of adaptive and distributed model predictive control.

• Analyzes the developments in control methods for wind turbines (focusing on type 3 and type 4 wind turbines)
• Provides an overview of the latest changes in grid code requirements for wind power integration
• Reviews the operation characteristics of the FSC and DFIG WTG
• Presents production efficiency improvement of WTG under uncertainties and disturbances with adaptive control
• Deals with model predictive active and reactive power control of wind power plants
• Describes enhanced control of VSC HVDC connected offshore wind power plants

Modeling and Modern Control of Wind Power is ideal for PhD students and researchers studying the field, but is also highly beneficial to engineers and transmission system operators (TSOs), wind turbine manufacturers, and consulting companies.

Edited by

Qiuwei Wu, PhD, is an Associate Professor at the Technical University of Denmark (DTU). His research areas include wind power integration and wind turbine modeling, the standard modeling of wind power, VSC HVDC connection for offshore wind power integration, coordinated control of wind power and energy storage systems.

Yuanzhang Sun, PhD, is a Full Professor at Wuhan University, Hubei Province, China. His research interests are power system stability and control, operational reliability of power systems, smart grid, and renewable energy.

List of Contributors xi

About the CompanionWebsite xiii

1 Status of Wind Power Technologies 1
Haoran Zhao and Qiuwei Wu

1.1 Wind Power Development 1

1.2 Wind Turbine Generator Technology 4

1.2.1 Type 1 4

1.2.2 Type 2 5

1.2.3 Type 3 5

1.2.4 Type 4 6

1.2.5 Comparison 7

1.2.6 Challenges withWind Power Integration 7

1.3 Conclusion 9

References 9

2 Grid Code Requirements for Wind Power Integration 11
Qiuwei Wu

2.1 Introduction 11

2.2 Steady-state Operational Requirements 12

2.2.1 Reactive Power and Power Factor Requirements 12

2.2.2 Continuous Voltage Operating Range 17

2.2.3 Frequency Operating Range and Frequency Response 18

2.2.4 Power Quality 24

2.3 Low-voltage Ride Through Requirement 26

2.3.1 LVRT Requirement in the UK 26

2.3.2 LVRT Requirement in Ireland 29

2.3.3 LVRT Requirement in Germany (Tennet TSO GmbH) 30

2.3.4 LVRT Requirement in Denmark 31

2.3.5 LVRT Requirement in Spain 31

2.3.6 LVRT Requirement in Sweden 32

2.3.7 LVRT Requirement in the USA 33

2.3.8 LVRT Requirement in Quebec and Alberta 34

2.4 Conclusion 36

References 36

3 Control of Doubly-fed Induction Generators for Wind Turbines 37
Guojie Li and Lijun Hang

3.1 Introduction 37

3.2 Principles of Doubly-fed Induction Generator 37

3.3 PQ Control of Doubly-fed Induction Generator 40

3.3.1 Grid-side Converter 41

3.3.2 Rotor-side converter 43

3.4 Direct Torque Control of Doubly-fed Induction Generators 46

3.4.1 Features of Direct Torque Control 47

3.4.2 Application of Direct Torque Control in DFIGs 49

3.4.3 Principle of Direct Torque Control in DFIG 50

3.5 Low-voltage Ride Through of DFIGs 58

3.6 Conclusions 61

References 61

4 Optimal Control Strategies of Wind Turbines for Load Reduction 63
Shuju Hu and Bin Song

4.1 Introduction 63

4.2 The Dynamic Model of aWind Turbine 64

4.2.1 Wind Conditions Model 64

4.2.2 Aerodynamic Model 64

4.2.3 Tower Model 66

4.2.4 DrivetrainModel 66

4.2.5 Electrical Control Model 67

4.2.6 Wind Turbine DynamicModel 67

4.3 Wind Turbine Individual Pitch Control 67

4.3.1 Control Implementation 68

4.3.2 Linearization of theWind Turbine Model 68

4.3.3 Controller Design 71

4.3.4 Simulation Analysis 73

4.4 Drivetrain Torsional Vibration Control 73

4.4.1 LQG Controller Design 73

4.4.2 Simulation Analysis 79

4.5 Conclusion 83

References 83

5 Modeling of Full-scale Converter Wind Turbine Generator 85
Yongning Chi, Chao Liu, Xinshou Tian, Lei Shi, and Haiyan Tang

5.1 Introduction 85

5.2 Operating Characteristics of FSC-WTGs 88

5.3 FSC-WTG Model 89

5.3.1 Shaft Model 89

5.3.2 Generator Model 91

5.3.3 Full-scale Converter Model 94

5.4 Full Scale Converter Control System 96

5.4.1 Control System of Generator-side Converter 97

5.4.2 Grid-side Converter Control System 101

5.5 Grid-connected FSC-WTG Stability Control 107

5.5.1 Transient Voltage Control of Grid-side Converter 108

5.5.2 Additional DC Voltage Coupling Controller 108

5.5.3 Simulations 109

5.6 Conclusion 114

References 114

6 Clustering-based Wind Turbine Generator Model Linearization 117
Haoran Zhao and Qiuwei Wu

6.1 Introduction 117

6.2 Operational Regions of Power-controlledWind Turbines 118

6.3 SimplifiedWind Turbine Model 119

6.3.1 Aerodynamics 119

6.3.2 Drivetrain 120

6.3.3 Generator 120

6.3.4 Tower 121

6.3.5 Pitch Actuator 121

6.4 Clustering-based IdentificationMethod 122

6.5 Discrete-time PWA Modeling ofWind Turbines 123

6.5.1 Identification of Aerodynamic Torque Ta 123

6.5.2 Identification of Generator Torque Tg 123

6.5.3 Identification of Thrust Force Ft 124

6.5.4 Identification of Correction Factor Kc 125

6.5.5 Formulation of A′ d and B′ d 126

6.5.6 Region Construction through Intersection 126

6.5.7 PWA Model of aWind Turbine 126

6.6 Case Study 127

6.6.1 LowWind Speed Case 128

6.6.2 HighWind Speed Case 129

6.7 Conclusion 131

References 131

7 Adaptive Control of Wind Turbines for Maximum Power Point Tracking 133
Haoran Zhao and Qiuwei Wu

7.1 Introduction 133

7.1.1 Hill-climbing Search Control 134

7.1.2 Power Signal Feedback Control 135

7.1.3 Tip-speed Ratio Control 135

7.2 Generator Control System forWECSs 135

7.2.1 Speed Reference Calculation 136

7.2.2 Generator Torque Control 138

7.2.3 Speed Control 139

7.3 Design of óD1 Adaptive Controller 140

7.3.1 Problem Formulation 140

7.3.2 Architecture of the óD1 Adaptive Controller 140

7.3.3 Closed-loop Reference System 142

7.3.4 Design of óD1 Adaptive Controller Parameters 142

7.4 Case Study 144

7.4.1 Wind Speed Estimation 144

7.4.2 MPPT Performance 144

7.5 Conclusion 147

References 148

8 Distributed Model Predictive Active Power Control of Wind Farms 151
Haoran Zhao and Qiuwei Wu

8.1 Introduction 151

8.2 Wind Farm without Energy Storage 152

8.2.1 Wind Farm Control Structure 152

8.2.2 Load Evaluation of theWind Turbine 154

8.2.3 MPC Problem Formulation 154

8.2.4 Standard QP Problem 156

8.2.5 Parallel Generalized Fast Dual Gradient Method 158

8.3 Wind Farm Equipped with Energy Storage 160

8.3.1 Wind Farm Control Structure 160

8.3.2 Modelling of ESS Unit 161

8.3.3 MPC Problem Formulation 162

8.4 Case Study 163

8.4.1 Wind Farm Control based on D-MPC without ESS 163

8.4.2 Wind Farm Control based on D-MPC with ESS 166

8.5 Conclusion 171

References 172

9 Model Predictive Voltage Control ofWind Power Plants 175
Haoran Zhao and Qiuwei Wu

9.1 Introduction 175

9.2 MPC-basedWFVC 176

9.3 Sensitivity Coefficient Calculation 178

9.3.1 Voltage Sensitivity to Reactive Power 178

9.3.2 Voltage Sensitivity to Tap Position 179

9.4 Modeling ofWTGs and SVCs/SVGs 180

9.4.1 WTG Modeling 180

9.4.2 SVC/SVG Modeling 181

9.4.3 General Composite Model 182

9.5 Coordination with OLTC 183

9.6 Formulation of MPC Problem forWFVC 184

9.6.1 Corrective Voltage Control Mode 184

9.6.2 Preventive Voltage Control Mode 186

9.7 Case Study 186

9.7.1 Scenario 1: Normal Operation 187

9.7.2 Scenario 2: Operation with Disturbances 187

9.8 Conclusion 190

References 191

10 Control of Wind Farm Clusters 193
Yan Li, Ningbo Wang, Linjun Wei, and Qiang Zhou

10.1 Introduction 193

10.2 Active Power and Frequency Control of Wind Farm Clusters 194

10.2.1 Active Power Control Mode of Wind Farms 194

10.2.2 Active Power Control Strategy of Wind Farm Cluster 198

10.2.3 AGC of Wind Farm Cluster 200

10.3 Reactive Power and Voltage Control of Wind Farms 200

10.3.1 Impact of Wind Farm on Reactive Power Margin of the System 200

10.3.2 Reactive Voltage Control Measures for Wind Farms 202

10.3.3 Reactive Voltage Control Strategy of Wind Farm Cluster 208

10.3.4 Wind Farm AVC Design Scheme 210

10.4 Conclusion 213

References 213

11 Fault Ride Through Enhancement of VSC-HVDC Connected Offshore Wind Power Plants 215
Ranjan Sharma, Qiuwei Wu, Kim Høj Jensen, Tony Wederberg Rasmussen, and Jacob Østergaard

11.1 Introduction 215

11.2 Modeling and Control of VSC-HVDC-connected Offshore WPPs 216

11.2.1 Modeling of VSC-HVDC-connected WPP with External Grid 217

11.2.2 Modeling of VSC-HVDC-connected WPP 217

11.2.3 Control of WPP-side VSC 220

11.3 Feedforward DC Voltage Control based FRT Technique for VSC-HVDC-connected WPP 222

11.4 Time-domain Simulation of FRT for VSC-HVDC-connected WPPs 223

11.4.1 Test System for Case Studies 224

11.4.2 Case Study 224

11.5 Conclusions 229

References 230

12 Power Oscillation Damping from VSC-HVDC-connected Offshore Wind Power Plants 233
Lorenzo Zeni

12.1 Introduction 233

12.1.1 HVDC Connection of Offshore WPPs 233

12.1.2 Power Oscillation Damping from Power Electronic Sources 234

12.2 Modelling for Simulation 235

12.2.1 HVDC System 235

12.2.2 Wind Power Plant 237

12.2.3 Power System 238

12.3 POD from Power Electronic Sources 238

12.3.1 Study Case 238

12.3.2 POD Controller 241

12.3.3 Practical Considerations for Parameter Tuning 241

12.4 Implementation on VSC-HVDC-connected WPPs 245

12.4.1 Realization of POD Control 245

12.4.2 Demonstration on Study Case 246

12.4.3 Practical Considerations on Limiting Factors 248

12.5 Conclusion 254

Acknowledgement 254

References 254

Index 257

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