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ISBN: 978-1-118-98858-9

CONTENTS

About the Authors

Preface

Acknowledgments

Acronyms

Symbols

Part I Preliminaries

Chapter 1 Basics of Wind Energy Conversion Systems (WECS)
1. 1.1 Introduction
2. 1.2 Wind Energy Preliminaries
  1. 1.2.1 Installed Wind Power Capacity
  2. 1.2.2 Wind Kinetic Energy to Electric Energy Conversion
  3. 1.2.3 Classification of Wind Energy Technologies
3. 1.3 Major Components of WECS
  1. 1.3.1 Mechanical Components
  2. 1.3.2 Electrical Components
  3. 1.3.3 Mechanical and Electrical Control Systems
4. 1.4 Grid Code Requirements for High-Power WECS
  1. 1.4.1 Fault Ride-Through
  2. 1.4.2 Reactive Power Generation
5. 1.5 WECS Commercial Configurations
  1. 1.5.1 Type 1 WECS Configuration
  2. 1.5.2 Type 2 WECS Configuration
  3. 1.5.3 Type 3 WECS Configuration
  4. 1.5.4 Type 4 WECS Configuration
  5. 1.5.5 Type 5 WECS Configuration
  6. 1.5.6 Comparison of WECS Configurations
6. 1.6 Power Electronics in Wind Energy Systems
7. 1.7 Control of Wind Energy Systems
  1. 1.7.1 TSO/DSO Supervisory Control (Level VI)
  2. 1.7.2 Wind Farm Centralized Control (Level V)
  3. 1.7.3 WT Centralized Control (Level IV)
  4. 1.7.4 Grid Integration and MPPT Control (Level III)
  5. 1.7.5 Power Converter, Wind Generator, and Grid Control (Level I and II)
8. 1.8 Finite Control-Set Model Predictive Control
  1. 1.8.1 Main Features of FCS-MPC
  2. 1.8.2 Challenges of FCS-MPC
9. 1.9 Classical and Model Predictive Control of WECS
  1. 1.9.1 Classical Control of WECS
  2. 1.9.2 Model Predictive Control of WECS
  3. 1.9.3 Comparison of Classical and Model Predictive Control
10. 1.10 Concluding Remarks
11. References
Chapter 2 Review of Generator-Converter Configurations for WECS
1. 2.1 Introduction
2. 2.2 Requirements for Power Converters in MW-WECS
3. 2.3 Overview of Power Converters for WECS
4. 2.4 Back-to-Back Connected Power Converters
  1. 2.4.1 Low-Voltage BTB Converters
  2. 2.4.2 Medium-Voltage BTB Converters
  3. 2.4.3 Comparison of BTB Power Converters
5. 2.5 Passive Generator-side Power Converters
  1. 2.5.1 Low-Voltage PGS Converters
  2. 2.5.2 Medium-Voltage PGS Converters
6. 2.6 Power Converters for Multiphase Generators
  1. 2.6.1 Power Converters for Six-Phase Generators
  2. 2.6.2 Power Converters for Open-Winding Generators
7. 2.7 Power Converters without an Intermediate DC Link
  1. 2.7.1 Low-Voltage Matrix Converters
  2. 2.7.2 Medium-Voltage Matrix Converters
8. 2.8 Concluding Remarks
9. References
Chapter 3 Overview of Digital Control Techniques
1. 3.1 Introduction
2. 3.2 The Past, Present, and Future of Control Platforms
3. 3.3 Reference Frame Theory
  1. 3.3.1 Definition of Natural Frame Space Phasor
  2. 3.3.2 Transformation Between Natural and Stationary Frames
  3. 3.3.3 Transformation Between Natural and Synchronous Frames
  4. 3.3.4 Transformation Between Stationary and Synchronous Frames
4. 3.4 Digital Control of Power Conversion Systems
  1. 3.4.1 Block Diagram of Digital Current Control
  2. 3.4.2 Model of Two-Level VSC for Digital Current Control
5. 3.5 Classical Control Techniques
  1. 3.5.1 Hysteresis Control
  2. 3.5.2 Linear Control
6. 3.6 Advanced Control Techniques
  1. 3.6.1 Sliding Mode Control
  2. 3.6.2 Intelligent Control
7. 3.7 Predictive Control Techniques
  1. 3.7.1 Predictive Control with Modulation
  2. 3.7.2 Predictive Control without Modulation
8. 3.8 Comparison of Digital Control Techniques
9. 3.9 Concluding Remarks
10. References
Chapter 4 Fundamentals of Model Predictive Control
1. 4.1 Introduction
2. 4.2 Sampled-Data Model
3. 4.3 Basics of Model Predictive Control
  1. 4.3.1 Operating Principle
  2. 4.3.2 Design Procedure
  3. 4.3.3 Implementation of Control Scheme
  4. 4.3.4 Stability-Related Issues
4. 4.4 Cost Function Flexibility
  1. 4.4.1 Primary Control Objectives
  2. 4.4.2 Secondary Control Objectives
5. 4.5 Weighting Factor Selection
  1. 4.5.1 Heuristic Selection
  2. 4.5.2 Per-Unit Method
  3. 4.5.3 LookupTable-Based Selection
  4. 4.5.4 Multiobjective Ranking Algorithm
6. 4.6 Delay Compensation Methods
  1. 4.6.1 Estimation +Prediction Approach
  2. 4.6.2 Prediction +Double Prediction Approach
  3. 4.6.3 Prediction +Prediction Approach
  4. 4.6.4 Long Prediction Horizons
7. 4.7 Extrapolation Techniques
  1. 4.7.1 Discrete Signal Generator
  2. 4.7.2 Vector Angle Extrapolation
  3. 4.7.3 Lagrange Extrapolation
8. 4.8 Selection of Sampling Time
9. 4.9 Concluding Remarks
10. References

Part II Modeling of power converters and wind generators

Chapter 5 Modeling of Power Converters for Model Predictive Control
1. 5.1 Introduction
2. 5.2 Objectives for the Modeling of Power Converters
3. 5.3 Notation Employed for the Modeling
4. 5.4 Two-Level Voltage Source Converter
  1. 5.4.1 Power Circuit
  2. 5.4.2 Operating Modes
  3. 5.4.3 Model of Output AC Voltages
  4. 5.4.4 Model of Input DC Branch Currents
5. 5.5 Extensions to 2L-VSC Modeling
  1. 5.5.1 Modeling of Multiphase 2L-VSC
  2. 5.5.2 Modeling of BTB 2L-VSC
6. 5.6 Neutral-Point Clamped Converter
  1. 5.6.1 Power Circuit
  2. 5.6.2 Operating Modes
  3. 5.6.3 Model of Output AC Voltages
  4. 5.6.4 Model of Input DC Branch Currents
7. 5.7 Extensions to NPC Converter Modeling
  1. 5.7.1 Modeling of Multilevel and Multiphase DCC
  2. 5.7.2 Modeling of BTB NPC Converter
8. 5.8 Modeling of Other Power Converters
  1. 5.8.1 Three-Level Flying Capacitor Converter
  2. 5.8.2 Current Source Converter
  3. 5.8.3 Direct Matrix Converter
  4. 5.8.4 Indirect Matrix Converter
9. 5.9 Concluding Remarks
10. References
Chapter 6 Modeling of Wind Generators for Model Predictive Control
1. 6.1 Introduction
2. 6.2 Overview of Wind Generators for Variable-Speed WECS
  1. 6.2.1 Synchronous Generators for WECS
  2. 6.2.2 Induction Generators for WECS
3. 6.3 Objectives for the Dynamic Modeling of Wind Generators
4. 6.4 Notation Employed for the Dynamic Modeling
5. 6.5 Modeling of Permanent Magnet Synchronous Generator
  1. 6.5.1 Stationary Frame Model
  2. 6.5.2 Stator Voltages in Synchronous Frame
  3. 6.5.3 Stator Flux Linkages in Synchronous Frame
  4. 6.5.4 Stator Current Dynamics in Synchronous Frame
  5. 6.5.5 Stator Active and Reactive Power
  6. 6.5.6 Electromagnetic Torque and Rotor Speed
6. 6.6 Simulation of Permanent Magnet Synchronous Generator
7. 6.7 Modeling of Induction Generator
  1. 6.7.1 Space Vector Model
  2. 6.7.2 Modeling in Arbitrary Reference Frame
  3. 6.7.3 Modeling in Synchronous Reference Frame
  4. 6.7.4 Modeling in Stationary Reference Frame
8. 6.8 Simulation of Induction Generator
9. 6.9 Generator Dynamic Models for Predictive Control
10. 6.10 Concluding Remarks
11. References
Chapter 7 Mapping of Continuous-Time Models to Discrete-Time Models
1. 7.1 Introduction
2. 7.2 Model Predictive Control of WECS
3. 7.3 Correlation Between CT and DT Models
  1. 7.3.1 CT and DT State-Space Equations
  2. 7.3.2 CT and DT Transfer Functions
4. 7.4 Overview of Discretization Methods
5. 7.5 Exact Discretization by ZOH Method
6. 7.6 Approximate Discretization Methods
  1. 7.6.1 Forward Euler Approximation
  2. 7.6.2 Backward Euler Approximation
  3. 7.6.3 Approximation by Bilinear Transformation
7. 7.7 Quasi-Exact Discretization Methods
  1. 7.7.1 Matrix Factorization
  2. 7.7.2 Truncated Taylor Series
8. 7.8 Comparison of Discretization Methods
9. 7.9 Offline Calculation of DT Parameters Using MATLAB
10. 7.10 Concluding Remarks
11. References

Part III Control of variable-speed wecs

Chapter 8 Control of Grid-side Converters in WECS
1. 8.1 Introduction
2. 8.2 Configuration of GSCs in Type 3 and 4 WECS
  1. 8.2.1 Single-Stage Power Conversion
  2. 8.2.2 Two-Stage Power Conversion
  3. 8.2.3 Three-Stage Power Conversion
3. 8.3 Design and Control of GSC
  1. 8.3.1 Design of Passive Components
  2. 8.3.2 Design of Reference DC-Bus Voltage
  3. 8.3.3 Definition of Grid Power Factor
  4. 8.3.4 Grid Voltage Orientation
4. 8.4 Modeling of Three-Phase GSC
  1. 8.4.1 Modeling of abc-Frame Grid Currents and Powers
  2. 8.4.2 Modeling of αβ-Frame Grid Currents and Powers
  3. 8.4.3 Modeling of dq-Frame Grid Currents and Powers
  4. 8.4.4 Modeling of VSI Output Voltages
  5. 8.4.5 Modeling of DC Link Capacitors Voltage in NPC Inverter
5. 8.5 Calculation of Reference Grid-side Variables
  1. 8.5.1 Generator-side MPPT
  2. 8.5.2 Grid-side MPPT
6. 8.6 Predictive Current Control of 2L-VSI in dq-Frame
  1. 8.6.1 Design Procedure
  2. 8.6.2 Control Algorithm
  3. 8.6.3 Comparison of the PCC Design with VOC
  4. 8.6.4 Comparison of GSC Performance with Passive Load Case
  5. 8.6.5 Switching Frequency Regulation
7. 8.7 Predictive Current Control of NPC Inverter in αβ-Frame
  1. 8.7.1 Design Procedure
  2. 8.7.2 Control Algorithm
8. 8.8 Predictive Power Control of NPC Inverter with Grid-side MPPT
  1. 8.8.1 Design Procedure
  2. 8.8.2 Control Algorithm
9. 8.9 Real-Time Implementation of MPC Schemes
10. 8.10 Concluding Remarks
11. References
Chapter 9 Control of PMSG WECS with Back-to-Back Connected Converters
1. 9.1 Introduction
2. 9.2 Configuration of PMSG WECS with BTB Converters
  1. 9.2.1 PMSG WECS with LV BTB Converters
  2. 9.2.2 PMSG WECS with MV BTB Converters
  3. 9.2.3 Power Flow in PMSG WECS
3. 9.3 Modeling of Permanent Magnet Synchronous Generator
  1. 9.3.1 Steady-State Models of PMSG
  2. 9.3.2 Continuous-Time Dynamic Models of PMSG
  3. 9.3.3 Discrete-Time Dynamic Models of PMSG
4. 9.4 Control of Permanent Magnet Synchronous Generator
  1. 9.4.1 Zero d-axis Current Control
  2. 9.4.2 Maximum Torque per Ampere Control
5. 9.5 Digital Control of BTB Converter-Based PMSG WECS
  1. 9.5.1 Block Diagram of the Digital Control System
  2. 9.5.2 Control Requirements
  3. 9.5.3 Notation of Variables
  4. 9.5.4 Calculation of Reference Control Variables
6. 9.6 Predictive Current Control of BTB 2L-VSC-Based PMSG WECS
  1. 9.6.1 Generator-side Control Scheme
  2. 9.6.2 Grid-side Control Scheme
  3. 9.6.3 Control Algorithm
7. 9.7 Predictive Current Control of BTB-NPC-Converter-Based PMSG WECS
  1. 9.7.1 Generator-side Control Scheme
  2. 9.7.2 Grid-side Control Scheme
  3. 9.7.3 Control Algorithm
  4. 9.7.4 Extension of PCC to Other Multilevel Converters
8. 9.8 Predictive Torque Control of BTB 2L-VSC-Based PMSG WECS
  1. 9.8.1 Generator-side Control Scheme
  2. 9.8.2 Control Algorithm
  3. 9.8.3 Extension of PTC to BTB NPC Converter
9. 9.9 Other MPC Schemes for PMSG WECS
  1. 9.9.1 Predictive Power Control
  2. 9.9.2 Predictive Speed Control
10. 9.10 Real-Time Implementation of MPC Schemes
11. 9.11 Concluding Remarks
12. References
Chapter 10 Control of PMSG WECS with Passive Generator-side Converters
1. 10.1 Introduction
2. 10.2 Configuration of PMSG WECS with PGS Converters
  1. 10.2.1 PMSG WECS with LV PGS Converters
  2. 10.2.2 PMSG WECS with MV PGS Converters
  3. 10.2.3 Comparison Between BTB and PGS Converters
3. 10.3 Modeling of the Two-Level Boost Converter
  1. 10.3.1 Power Circuit
  2. 10.3.2 Operating Modes
  3. 10.3.3 Continuous-Time Model
  4. 10.3.4 Discrete-Time Model
4. 10.4 Modeling of the Three-Level Boost Converter
  1. 10.4.1 Power Circuit
  2. 10.4.2 Operating Modes
  3. 10.4.3 Continuous-Time Model
  4. 10.4.4 Discrete-Time Model
  5. 10.4.5 Extension of Modeling to Multilevel Boost Converters
5. 10.5 Digital Control of PGS Converter-Based PMSG WECS
  1. 10.5.1 Block Diagram of Digital Control System
  2. 10.5.2 Control Requirements
  3. 10.5.3 Notation of Variables
  4. 10.5.4 Calculation of Reference Control Variables
6. 10.6 Predictive Current Control of 2L-PGS-Converter-Based PMSG WECS
  1. 10.6.1 Generator-side Control Scheme
  2. 10.6.2 Control Algorithm
7. 10.7 Predictive Current Control of 3L-PGS-Converter-Based PMSG WECS
  1. 10.7.1 Generator-side Control Scheme
  2. 10.7.2 Control Algorithm
8. 10.8 Analysis of PMSG WECS Performance with PGS Converters
9. 10.9 Other MPC Schemes for PMSG WECS
  1. 10.9.1 Predictive Power Control
  2. 10.9.2 Predictive Speed Control
10. 10.10 Real-Time Implementation of MPC Schemes
11. 10.11 Concluding Remarks
12. References
Chapter 11 Control of SCIG WECS with Voltage Source Converters
1. 11.1 Introduction
2. 11.2 Configuration of SCIG WECS with BTB Converters
  1. 11.2.1 SCIG WECS with LV BTB Converters
  2. 11.2.2 SCIG WECS with MV BTB Converters
3. 11.3 Modeling of Squirrel-Cage Induction Generator
  1. 11.3.1 Equivalent Circuit of SCIG
  2. 11.3.2 Continuous-Time Dynamic Models of SCIG
  3. 11.3.3 Discrete-Time Dynamic Models of SCIG
4. 11.4 Control of Squirrel-Cage Induction Generator
  1. 11.4.1 Field-Oriented Control
  2. 11.4.2 Direct Torque Control
5. 11.5 Digital Control of BTB Converter-Based SCIG WECS
  1. 11.5.1 Block Diagram of Digital Control System
  2. 11.5.2 Calculation of Reference Control Variables
6. 11.6 Predictive Current Control of BTB 2L-VSC-Based SCIG WECS
  1. 11.6.1 Generator-side Control Scheme
  2. 11.6.2 Grid-side Control Scheme
  3. 11.6.3 Control Algorithm
7. 11.7 Predictive Torque Control of BTB NPC Converter-Based SCIG WECS
  1. 11.7.1 Generator-side Control Scheme
  2. 11.7.2 Grid-side Control Scheme
  3. 11.7.3 Control Algorithm
8. 11.8 Real-Time Implementation of MPC Schemes
9. 11.9 Concluding Remarks
10. References
Chapter 12 Control of DFIG WECS with Voltage Source Converters
1. 12.1 Introduction
2. 12.2 Configuration of DFIG WECS and Power Flow
  1. 12.2.1 Power Conversion Configuration
  2. 12.2.2 Power Flow in DFIG WECS
3. 12.3 Control of Doubly Fed Induction Generator
  1. 12.3.1 Stator Flux-Oriented Control
  2. 12.3.2 Stator Voltage-Oriented Control
4. 12.4 Modeling of Doubly Fed Induction Generator
  1. 12.4.1 Equivalent Circuit of DFIG
  2. 12.4.2 Correlation Between Rotor Currents and Control Requirements
  3. 12.4.3 Continuous-Time Dynamic Models of DFIG
  4. 12.4.4 Discrete-Time Dynamic Models of DFIG
5. 12.5 Digital Control of BTB Converter-Based DFIG WECS
  1. 12.5.1 Block Diagram of Digital Control System
  2. 12.5.2 Calculation of Reference Control Variables
6. 12.6 Indirect Predictive Current Control of DFIG WECS
  1. 12.6.1 Generator-side Control Scheme
  2. 12.6.2 Grid-side Control Scheme
  3. 12.6.3 Control Algorithm
7. 12.7 Direct Predictive Current Control of DFIG WECS
8. 12.8 Concluding Remarks
9. References

Appendix A Turbine and Generator Parameters

A.1 Notation of Generator Variables
A.2 Base Values
A.3 Per-Unit Values
A.4 Wind Turbine Parameters
A.5 Three-Phase Grid Parameters
A.6 Permanent Magnet Synchronous Generator Parameters
A.7 Squirrel-Cage Induction Generator Parameters
A.8 Doubly Fed Induction Generator Parameters

Appendix B Chapter Appendices

B.1 Appendix for Chapter 4
References
B.2 Appendix for Chapter 5

Appendix C MATLAB Demo Projects

Index

List of Tables

Chapter 1

Table 1.1
Table 1.2
Table 1.3
Table 1.4
Table 1.5
Table 1.6

Chapter 2

Table 2.1
Table 2.2

Chapter 3

Table 3.1
Table 3.2

Chapter 4

Table 4.1
Table 4.2
Table 4.3
Table 4.4
Table 4.5
Table 4.6

Chapter 5

Table 5.1
Table 5.2
Table 5.3
Table 5.4
Table 5.5
Table 5.6
Table 5.7
Table 5.8

Chapter 6

Table 6.1

Chapter 7

Table 7.1
Table 7.2
Table 7.3
Table 7.4

Chapter 8

Table 8.1
Table 8.2

Chapter 9

Table 9.1

Chapter 10

Table 10.1
Table 10.2
Table 10.3
Table 10.4
Table 10.5
Table 10.6
Table 10.7
Table 10.8

Chapter 11

Table 11.1

Chapter 12

Table 12.1

List of Illustrations

Preface

Figure 0.1 Organization of parts and chapters in this book.

Chapter 1

Figure 1.1 Global cumulative installed wind power from 1997 to 2014 [2].
Figure 1.2 Global annual installed wind power from 1997 to 2014 [2].
Figure 1.3 Top 10 countries in the cumulative installed wind power by December 2014 [2].
Figure 1.4 Top 10 countries in the new installed wind power from January to December 2014 [2].
Figure 1.5 Block diagram of wind kinetic energy to electric energy conversion system.
Figure 1.6 WT power characteristic curves with respect to wind speed.
Figure 1.7 Major types of prevailing wind energy technologies.
Figure 1.8 Evolution in the commercial WT size (P_T, rated turbine output power; D_T, turbine rotor diameter; H_T, hub height).
Figure 1.9 Aerodynamic power regulation of WTs by different control methods [11].
Figure 1.10 Characteristics of FSWT and VSWT during different wind-speed conditions.
Figure 1.11 Global cumulative installed offshore wind power from 1997 to 2014 [2, 16].
Figure 1.12 Major components of a variable-speed high-power WECS.
Figure 1.13 FRT requirement according to the E.ON regulation [28].
Figure 1.14 Reactive power requirement for grid-connected WECS.
Figure 1.15 Type 1 WECS with fixed-speed (1%) SCIG, three-stage gearbox, soft starter, and reactive power compensator.
Figure 1.16 Type 2 WECS with semi-variable-speed (10%) WRIG, converter-controlled external resistor, three-stage gearbox, soft starter, and reactive power compensator.
Figure 1.17 Type 3 WECS with semi-variable-speed (±30%) DFIG, three-stage gearbox, and partial-scale (30%) power converter.
Figure 1.18 Configuration of Type 4 WECS with full-variable speed (0 – 100%) wind generators, optional gearbox, and full-scale power converter.
Figure 1.19 Configuration of Type 5 WECS with a fixed-speed WRSG, three-stage gearbox, and steed-torque converter.
Figure 1.20 Top 10 WT manufacturers in 2014, along with their priority WECS configurations.
Figure 1.21 Taxonomy of power converters for Type 3 and 4 variable-speed WECS.
Figure 1.22 Block diagram of the overall control scheme for variable-speed WECS [5, 30, 42].
Figure 1.23 Pitch control system for high-power WTs (D-I/O: digital input/output).
Figure 1.24 Analysis of wind energy system without and with pitch control system.
Figure 1.25 Power characteristics and notation of variables for VSWT.
Figure 1.26 MPPT control of variable-speed wind energy systems.
Figure 1.27 Taxonomy of power converter control techniques [48, 49]. (GPC, generalized predictive control; DCC, direct current control; P-DPC, predictive direct power control; M² PC, modulated MPC; VSF-MPC, variable sampling frequency MPC; and S-MPC, switched MPC)
Figure 1.28 Taxonomy of wind generator control techniques [60].
Figure 1.29 Main features of finite control-set model predictive control.
Figure 1.30 Classical zero d-axis current control of 2L-VSR-based PMSG WECS.
Figure 1.31 Predictive current control of 2L-VSR-based PMSG WECS.

Chapter 2

Figure 2.1 Classification of power converters for variable-speed wind energy systems.
Figure 2.2 Classification of power converters with respect to voltage of operation and power flow.
Figure 2.3 Classification of BTB connected power converters for variable-speed WECS.
Figure 2.4 Type 4 WECS with SCIG/SG and full-scale (100%) BTB connected 2L-VSC.
Figure 2.5 Type 3 WECS with DFIG and partial-scale (30%) BTB connected 2L-VSC.
Figure 2.6 Type 4 WECS with two VSCs in parallel for high current/power applications (common DC-link configuration; also applicable for Type 3 WECS).
Figure 2.7 Type 4 WECS with multiple VSCs in parallel for high current/power application (individual DC-link configuration; also applicable for Type 3 WECS).
Figure 2.8 Type 4 WECS with BTB connected NPC converter.
Figure 2.9 Type 4 WECS with BTB connected MMC.
Figure 2.10 Type 4 WECS with BTB connected CSC.
Figure 2.11 Classification of PGS power converters for Type 4 WECS.
Figure 2.12 Type 4 SG WECS with diode bridge rectifier and 2L-VSI.
Figure 2.13 Type 4 SG WECS with diode bridge rectifier, 2L boost converter, and 2L-VSI.
Figure 2.14 Type 4 SG WECS with diode bridge rectifier, 3L boost converter, and NPC inverter.
Figure 2.15 Type 4 SG WECS with diode rectifier, 2L buck converter, and CSI.
Figure 2.16 Classification of power converters for multiphase generator-based Type 4 WECS.
Figure 2.17 Type 4 WECS with a six-phase generator and distributed 2L-VSCs.
Figure 2.18 Configuration of Type 4 WECS with six-phase PMSG/WRSG, parallel 2L-boost converters, and parallel 2L-VSIs.
Figure 2.19 Type 4 WECS with a six-phase generator, cascaded 2L-VSRs on the generator side, and an NPC inverter on the grid side.
Figure 2.20 Block diagram of Type 4 WECS with open winding generator, distributed BTB VSCs, and open winding transformer.
Figure 2.21 Type 4 WECS with open winding generator and cascaded VSCs.
Figure 2.22 Submodule configurations for Figure 2.21: (a) BTB 3L H-bridge, (b) 1ϕ diode bridge rectifier + 2L boost converter + 3L H-bridge, and (c) BTB 3L H-bridge with an intermediate DC/DC conversion stage.
Figure 2.23 Classification of matrix converters for variable-speed WECS.
Figure 2.24 Type 4 WECS with 3ϕ to 3ϕ DMC (also applicable for Type 3 WECS).
Figure 2.25 Block diagram of Type 4 WECS with MMMC.
Figure 2.26 Simplified representation of multi-modular matrix converter.
Figure 2.27 Configuration of single-phase to three-phase matrix converter module.

Chapter 3

Figure 3.1 Type 3/4 WECS with a power converter and digital control system.
Figure 3.2 Evolution in semiconductor devices and associated control platforms.
Figure 3.3 Representation of three-phase variables and corresponding space phasor at
Figure 3.4 Representation of stationary frame variables and corresponding space phasor.
Figure 3.5 Natural (abc) frame voltages and corresponding synchronous (dq) frame voltages.
Figure 3.6 Simplified block diagram of digital control system for a current control of 3ϕ-VSC.
Figure 3.7 Hysteresis current control scheme for regulating three-phase load currents.
Figure 3.8 Operating principle of single-phase hysteresis current control scheme.
Figure 3.9 Linear current control scheme using PI regulator and modulation stage.
Figure 3.10 Simplified representation of closed-loop control scheme for a 2L-VSC.
Figure 3.11 Operating principle of SPWM.
Figure 3.12 Simulation model of SVM for a 2L-VSC [10].
Figure 3.13 Operating principle of SVM for a 2L-VSC.
Figure 3.14 SVM seven-segment switching scheme for all six sectors.
Figure 3.15 Block diagram of SMC with a modulation stage.
Figure 3.16 Block diagram of FLC with a modulation stage.
Figure 3.17 Block diagram of ANN-based load current control scheme.
Figure 3.18 Deadbeat predictive current control with a modulation stage.
Figure 3.19 Block diagram of FCS-MPC for regulating load currents.

Chapter 4

Figure 4.1 Operating principle of MPC (N_p = prediction horizon).
Figure 4.2 Predictive current control (PCC) of three-phase 2L-VSC with passive load.
Figure 4.3 Flowchart for 2L-VSC predictive current control algorithm.
Figure 4.4 Cost function in FCS-MPC with several primary and secondary control objectives.
Figure 4.5 One-sample-ahead FCS-MPC based on the single prediction (P) approach (ideal case).
Figure 4.6 Simulation waveforms for FCS-MPC without and with delay compensation.
Figure 4.7 Delay compensation based on the E+P approach.
Figure 4.8 Delay compensation based on the P+P² approach.
Figure 4.9 Delay compensation based on the P+P approach.
Figure 4.10 Simulation waveforms of FCS-MPC without and with extrapolation.
Figure 4.11 Simulation waveforms of present and future references by a discrete signal generator.
Figure 4.12 Simulation waveforms for present and future references by vector angle extrapolation.
Figure 4.13 Simulation waveforms of FCS-MPC with different sampling times.

Chapter 5

Figure 5.1 Block diagram of the PCC scheme for 2L-VSR-based PMSG WECS.
Figure 5.2 Per-phase 2L-VSC power circuit using: (a) IGBT switches, and (b) generic switches.
Figure 5.3 Per-phase representation of 2L-VSC operating modes.
Figure 5.4 Space vector diagram for a 2L-VSC [2] (x ∊ {a, b, c}).
Figure 5.5 Representation of 2L-VSC DC branch (input) and output currents.
Figure 5.6 Power circuit of BTB 2L-VSC.
Figure 5.7 Per-phase NPC converter power circuit using: (a) semiconductor switches and diodes, and (b) generic switches and diodes.
Figure 5.8 Per-phase representation of operating modes for an NPC converter.
Figure 5.9 Space vector diagram for NPC converter [12, 13].
Figure 5.10 Representation of NPC converter DC branch (input) and output currents.
Figure 5.11 Power circuit of BTB connected NPC converter.
Figure 5.12 Per-phase 3L-FCC power circuit using: (a) IGBT switches and (b) generic switches.
Figure 5.13 Per-phase representation of a CSC power circuit using: (a) SGCT switches, and (b) generic switches, and the DC-link model.
Figure 5.14 Power circuit of DMC using generic switches.
Figure 5.15 Power circuit of IMC using generic switches.

Chapter 6

Figure 6.1 Taxonomy of three-phase SGs for variable-speed WECS.
Figure 6.2 Taxonomy of three-phase IGs for variable-speed WECS.
Figure 6.3 Variable-speed applications employing PMS machine.
Figure 6.4 PMSM stator voltage and current waveforms using motor and generator convention.
Figure 6.5 Representation of PMSM in natural and synchronous reference frames.
Figure 6.6 Correlation between the PMSM reference phase-a rotor flux ψ_ar and θ_r.
Figure 6.7 Representation of the three-phase PMSM with a power converter.
Figure 6.8 Representation of the standard dq-axes equivalent circuits for a PMSM through stator flux derivative terms [17].
Figure 6.9 Representation of simplified dq-axis steady-state circuits for a PMSM (stator current dynamics are ignored).
Figure 6.10 Dynamic model of the permanent magnet synchronous machine.
Figure 6.11 Simulated waveforms for a SPMSG during startup with RC load.
Figure 6.12 Dynamic equivalent circuit of an induction machine in the arbitrary reference frame.
Figure 6.13 Simplified models of an induction machine: (a) stator voltage circuit, (b) magnetizing current circuit, and (c) rotor voltage circuit.
Figure 6.14 Equivalent circuit of an induction machine in the dq frame [20].
Figure 6.15 The equivalent circuit of an induction machine in the αβ reference frame.
Figure 6.16 Dynamic model of an induction machine in the synchronous reference frame.
Figure 6.17 Simulated waveforms for a SCIG with direct grid connection.

Chapter 7

Figure 7.1 Block diagram of a simplified WECS sampled-data model.
Figure 7.2 Block diagram of digital control system for Type 4 PMSG WECS.
Figure 7.3 Taxonomy of discretization methods for digital control realization.
Figure 7.4 Comparison of approximate discretization methods based on sampling instants [14].

Chapter 8

Figure 8.1 Block diagram of Type 3 and 4 WECS with power conversion configuration and primary and secondary control objectives.
Figure 8.2 Configuration and control objectives of Type 3 and 4 WECS with BTB 2L-VSC.
Figure 8.3 Configuration and control objectives of Type 4 WECS with BTB NPC converter.
Figure 8.4 Configuration and control objectives of Type 4 WECS with a 3ϕ diode-bridge rectifier and 2L-VSI/ NPC inverter.
Figure 8.5 Configuration and control objectives of Type 4 WECS with three-phase diode-bridge rectifier, 2L/3L boost converter and 2L-VSI/ NPC inverter.
Figure 8.6 Definition of power flow between grid and DC link, and grid PF.
Figure 8.7 Grid voltage and current vectors in dq and αβ frame. With v_qg = 0, the resultant grid active and reactive powers are defined by
Figure 8.8 Block diagram for grid voltage angle estimation under ideal grid conditions.
Figure 8.9 Block diagram for grid voltage angle estimation under distorted grid conditions.
Figure 8.10 Transformation of grid voltages from the abc-frame to αβ- and dq-frames.
Figure 8.11 Representation of abc-frame GSC: (a) standard model and (b) simplified model.
Figure 8.12 Representation of αβ-frame GSC: (a) standard model and (b) simplified model.
Figure 8.13 Representation of a dq-frame GSC: (a) standard model and (b) simplified model.
Figure 8.14 Power circuit of three-phase grid-connected 2L-VSI.
Figure 8.15 Power circuit of three-phase grid-connected NPC inverter.
Figure 8.16 Simplified representation of GSC with: (a) generator-side MPPT control and (b) grid-side MPPT control.
Figure 8.17 Calculation of reference grid-side control variables with generator-side MPPT control.
Figure 8.18 Calculation of reference grid-side control variables with grid-side MPPT control.
Figure 8.19 Block diagram of the dq-frame PCC scheme for grid-connected 2L-VSI.
Figure 8.20 Flowchart of the PCC algorithm for grid-connected 2L-VSI.
Figure 8.21 Block diagram of decoupled VOC for grid-connected 2L-VSI.
Figure 8.22 Comparison of the % THD versus the f_sw,i with grid-connected and resistive load cases.
Figure 8.23 Study of the variable switching frequency nature of the PCC scheme.
Figure 8.24 Steady-state waveforms for a 2L-VSI with , and .
Figure 8.25 Steady-state waveforms for a 2L-VSI with, and . v_ag:50 V/div, i_ag:20 A/div, i_dg:20 A/div, and i_qg: 20 A/div.
Figure 8.26 Block diagram of the αβ-frame PCC scheme for grid-connected NPC inverter.
Figure 8.27 Flowchart of the PCC algorithm for grid-connected NPC inverter.
Figure 8.28 Dynamic response of the αβ-frame PCC scheme during a step change in active power extraction (wind speed).
Figure 8.29 Dynamic response of the αβ-frame PCC scheme during trapezoidal changes in reactive power reference.
Figure 8.30 Block diagram of the dq-frame PPC scheme for grid-connected NPC inverter.
Figure 8.31 Flowchart of the PPC algorithm for grid-connected NPC inverter.
Figure 8.32 Performance of PPC scheme with dynamic active and reactive power references. v_w, 1.0 m/s/div; i_ag, 20 A/div; P_g, 5.0 kW/div; Q_g, 5.0 kVAR/div; and v_ag, 100 V/div.

Chapter 9

Figure 9.1 Block diagram of PMSG WECS with BTB 2L-VSC.
Figure 9.2 Block diagram of PMSG WECS with BTB NPC converter.
Figure 9.3 Sankey diagram for power flow in BTB-converter-based PMSG WECS.
Figure 9.4 Equivalent steady-state circuits and space vector diagram of PMSM.
Figure 9.5 Block diagram of digital control scheme for BTB-converter-based PMSG WECS.
Figure 9.6 Calculation of reference control variables for ZDC and MTPA control.
Figure 9.7 Reference control variables for SPMSG and IPMSG during startup.
Figure 9.8 Block diagram of the PCC scheme for ZDC control of the SPMSG with 2L-VSR.
Figure 9.9 Flowchart of the PCC algorithm for: (a) PMSG-side 2L-VSR and (b) grid-side 2L-VSI.
Figure 9.10 Graphical representation of the sample-based analysis of 2L-VSR with SPMSG.
Figure 9.11 Steady-state waveforms with the PCC scheme for 2L-VSC-based SPMSG WECS.
Figure 9.12 PCC scheme for the MTPA control of IPMSG with NPC rectifier.
Figure 9.13 Block diagram of the PCC scheme for the grid-connected NPC inverter.
Figure 9.14 Flowchart of the PCC algorithm for: (a) NPC rectifier and (b) NPC inverter.
Figure 9.15 Simulated waveforms with the PCC scheme for IPMSG WECS during startup.
Figure 9.16 Dynamic PCC response of IPMSG WECS during a step change in wind speed.
Figure 9.17 Block diagram of the PTC scheme for the ZDC control of PMSG with 2L-VSR.
Figure 9.18 Flowchart of the PTC algorithm for the 2L-VSR-based PMSG WECS.
Figure 9.19 Dynamic PTC response of SPMSG WECS during the step change in wind speed.
Figure 9.20 SPMSG electromagnetic torque and stator flux step response with the PTC scheme.
Figure 9.21 Block diagram of the 2H-PCC for ZDC/MTPA control of PMSG with 2L-VSR.
Figure 9.22 Flowchart of the 2H-PCC algorithm for the 2L-VSR-based PMSG WECS.

Chapter 10

Figure 10.1 Block diagram of PMSG WECS with diode rectifier, 2L boost converter, and 2L-VSI.
Figure 10.2 PMSG WECS with diode rectifier, 3L boost converter, and NPC inverter.
Figure 10.3 Three-phase PMSG phase voltage, stator current and electromagnetic torque waveforms, and harmonic spectrum under rated operating condition with PGS converters.
Figure 10.4 Representation of a 2L boost converter power circuit: (a) standard configuration and (b) simplified configuration.
Figure 10.5 Representation of operating modes for a 2L boost converter.
Figure 10.6 Representation of a 3L boost converter power circuit: (a) standard configuration and (b) simplified configuration.
Figure 10.7 Representation of operating modes for a 3L boost converter [17, 18].
Figure 10.8 Waveforms for the analysis of operating modes in a 3L boost converter (m is sampling instant number).
Figure 10.9 Block diagram of digital control scheme for PGS-converter-based PMSG WECS.
Figure 10.10 Calculation of reference control variables for PCC, PPC and PSC schemes.
Figure 10.11 Block diagram of the PCC scheme for a 2L boost converter-based PMSG WECS.
Figure 10.12 Flowchart of the PCC algorithm for 2L boost converter-based PMSG WECS.
Figure 10.13 Block diagram of the PCC scheme for a 3L boost converter-based PMSG WECS.
Figure 10.14 Flowchart of the PCC algorithm for a 3L boost converter-based PMSG WECS.
Figure 10.15 Graphical representation of sample-based analysis for a 3L boost converter.
Figure 10.16 Experimental waveforms for DC-link capacitors voltage with predictive controller (I: balanced condition, II: unbalanced condition due to lost of controller, III: recovery period from unbalanced to balanced condition).
Figure 10.17 Steady-state waveforms for a 3L boost converter-based PMSG WECS.
Figure 10.18 Simulated waveforms for a 3L boost converter-based PMSG WECS during step change in wind speed.
Figure 10.19 DC-link perturbation with R_x across C₁: (a) block diagram of test setup and (b) experimental waveforms.
Figure 10.20 Simulation waveforms for switching frequency reduction of grid-side NPC inverter in BTB NPC converter-based PMSG WECS.
Figure 10.21 Simulation waveforms for switching frequency reduction of grid-side NPC inverter in 3L PGS converter-based PMSG WECS.
Figure 10.22 Block diagram of the PCC scheme with P+P delay compensation for 2L boost converter-based PMSG WECS.
Figure 10.23 Flowchart for the PCC algorithm with P+P delay compensation for the 2L boost converter-based PMSG WECS.

Chapter 11

Figure 11.1 Block diagram of SCIG WECS with BTB 2L-VSC.
Figure 11.2 Block diagram of SCIG WECS with BTB NPC converter.
Figure 11.3 Equivalent circuit of an induction machine with 2L/3L MSC and WT.
Figure 11.4 Space vector diagram of SCIG for rotor flux-oriented control.
Figure 11.5 Block diagram of the FOC scheme for 2L-VSR-connected SCIG.
Figure 11.6 Input requirements for ψ_r and θ_e estimation with (a) DFOC and (b) IFOC.
Figure 11.7 Estimation of ψ_r and θ_e with DFOC scheme.
Figure 11.8 Estimation of ψ_r and θ_e with IFOC scheme.
Figure 11.9 Block diagram of the DTC scheme for a 2L-VSR-connected SCIG.
Figure 11.10 Block diagram of digital control scheme for BTB VSC-based SCIG WECS.
Figure 11.11 Calculation of reference control variables for the PCC and PTC schemes.
Figure 11.12 Reference control variables for SCIG during startup condition.
Figure 11.13 Block diagram of IFOC-based PCC scheme for SCIG with 2L-VSR.
Figure 11.14 Flowchart of the PCC algorithm for the (a) 2L-VSR and (b) 2L-VSI.
Figure 11.15 Steady-state waveforms with PCC scheme for 2L-VSC-based SCIG WECS.
Figure 11.16 Simulated waveforms with PCC scheme for SCIG WECS during startup.
Figure 11.17 Block diagram of the PTC scheme for NPC rectifier-based SCIG.
Figure 11.18 Flowchart of (a) PTC algorithm NPC rectifier and (b) PCC algorithm NPC inverter.
Figure 11.19 Simulated waveforms with PTC scheme during step change in wind speed.
Figure 11.20 Block diagram of the 2H PCC scheme for SCIG with 2L-VSR.

Chapter 12

Figure 12.1 Block diagram of DFIG WECS with BTB 2L-VSC.
Figure 12.2 Sankey diagram for power flow in BTB VSC-based DFIG WECS.
Figure 12.3 Estimation of stator flux angle and slip angle with the SFOC scheme.
Figure 12.4 Estimation of stator voltage angle and slip angle with the SVOC scheme.
Figure 12.5 Space vector diagram of DFIG with SVOC in supersynchronous mode [16].
Figure 12.6 Stator voltage angle, rotor position angle and slip angle in subsynchronous mode.
Figure 12.7 Stator voltage angle, rotor position angle and slip angle in supersynchronous mode.
Figure 12.8 Equivalent circuit of DFIG with the RSC and WFCP.
Figure 12.9 Block diagram of the digital control scheme for BTB VSC-based DFIG WECS.
Figure 12.10 Calculation of reference control variables for PCC of DFIG WECS.
Figure 12.11 Block diagram of the indirect PCC scheme for DFIG with RSC.
Figure 12.12 Flowchart of the dq-frame PCC algorithm for: (a) RSC and (b) GSC.
Figure 12.13 Steady-state waveforms for DFIG WECS during subsynchronous mode operation with the indirect PCC scheme (wind speed is 0.7 pu).
Figure 12.14 Steady-state waveforms for DFIG WECS during supersynchronous mode operation with the indirect PCC scheme (wind speed is 1.0 pu).
Figure 12.15 Transient waveforms for DFIG WECS during transition from subsynchronous to supersynchronous mode of operation.
Figure 12.16 Block diagram of the direct PCC scheme for DFIG with RSC.
Figure 12.17 Flowchart of the dq-frame PCC algorithm for: (a) RSC and (b) GSC.
Figure 12.18 Dynamic response of the direct PCC scheme-driven DFIG WECS during a step change in from 0 pu to −0.391 pu.
Figure 12.19 Dynamic response of the direct PCC scheme-driven DFIG WECS during a step change in from 0 pu to 0.391 pu.

ABOUT THE AUTHORS

Venkata Yaramasu was born in Karumanchi, Guntur, India. He received his B.Tech degree in electrical and electronics engineering from Jawaharlal Nehru Technological University, Hyderabad, India, in 2005, an M.E. degree in electrical engineering with specialization in power electronics from S. G. S. Institute of Technology and Science, Indore, India, in 2008, and Ph.D. degreein electrical engineering from Ryerson University, Toronto, Canada, in 2014. During 2014–2015, he worked as a Postdoctoral Research Fellow at the Laboratory for Electric Drive Applications and Research (LEDAR) and Center for Urban Energy (CUE), Ryerson University. He is currently working as an Assistant Professor of Electrical Engineering in the School of Informatics, Computing, and Cyber Systems (SICCS), Northern Arizona University, Flagstaff, Arizona, USA. His research interests include renewable energy, high-power converters, variable-speed drives, electric vehicles, power quality, energy storage, smartgrid, and model predictive control.

Dr. Yaramasu worked closely with Rockwell Automation, Toronto Hydro, Hydro One, Natural Sciences and Engineering Research Council of Canada (NSERC), Wind Energy Strategic Network (WESNet) and Connect Canada, and completed 8 industrial projects in Power Electronics, Electric Drives, and Renewable Energy. He has published more than 50 peer-reviewed technical papers including 22 journal papers. He has produced more than 10 technical reports for the industry.

Dr. Yaramasu received six Best Student Paper Awards and two first prizes in National Level Technical Quiz Competitions during his undergraduate studies in India. He is a recipient of a Second Prize Paper Award from the IEEE Journal of Emerging and Selected Topics in Power Electronics (JESTPE) in 2015. During his Ph.D. studies at Ryerson University, he received Best Poster Awards from the Electrical and Computer Engineering (ECE) Department and Faculty of Engineering and Architectural Science (FEAS) in 2013, Student Research Awards from the Toronto Hydro, Hydro One, and Connect Canada in 2010, 2012, and 2013, Research Excellence Awards from the ECE Department in 2012, 2013, and 2014, a Best Poster Award at the NSERC-WESNet Annual Meeting 2010, and a Best Teaching Assistant Award from the FEAS in 2010.

Bin Wu graduated from Donghua University, Shanghai, China in 1978, and received his M.A.Sc. and Ph.D. degrees in electrical and computer engineering from the University of Toronto, Canada in 1989 and 1993, respectively. After being with Rockwell Automation Canada from 1992 to 1993, he joined Ryerson University, where he is currently a Professor in the Department of Electrical and Computer Engineering and a Senior NSERC/Rockwell Industrial Research Chair (IRC) in Power Electronics and Electric Drives.

Dr. Wu has published more than 350 peer-reviewed technical papers and two Wiley-IEEE Press books, and he holds more than 30 issued and pending patents in power electronics, adjustable-speed drives, and renewable energy systems. Dr. Wu is the founder of the Laboratory for Electric Drive Applications and Research (LEDAR), which has been recognized as the most advanced research facility of its kind in a Canadian university.

Dr. Wu has worked closely with Canadian companies and assisted them in achieving technical and commercial success through research and innovation. He has authored/coauthored more than 200 technical reports. Some of his inventions and patents have been adopted by industry and implemented in the production line, resulting in significant economic benefits.

Dr. Wu received the Gold Medal of the Governor General of Canada in 1993, the Premier’s Research Excellence Award in 2001, the NSERC Synergy Award for Innovation in 2002, the Ryerson Distinguished Scholar Award in 2003, the Ryerson FEAS Research Excellence Award in 2007, the Ryerson YSGS Outstanding Contribution to Graduate Education Award and the Professional Engineers Ontario (PEO) Engineering Excellence Medal in 2014. He is a fellow of Institute of Electrical and Electronics Engineers (IEEE), Engineering Institute of Canada (EIC), and Canadian Academy of Engineering (CAE). Dr. Wu is a Registered Professional Engineer in the Province of Ontario, Canada.

George W. Arnold	Xiaoou Li	Ray Perez
Giancarlo Fortino	Vladimir Lumelsky	Linda Shafer
Dmitry Goldgof	Pui-In Mak	Zidong Wang
Ekram Hossain	Jeffrey Nanzer	MengChu Zhou

MODEL PREDICTIVE
CONTROL OF WIND
ENERGY CONVERSION
SYSTEMS

VENKATA YARAMASU

BIN WU

ABOUT THE AUTHORS

MODEL PREDICTIVECONTROL OF WINDENERGY CONVERSIONSYSTEMS

VENKATA YARAMASU

BIN WU

MODEL PREDICTIVE
CONTROL OF WIND
ENERGY CONVERSION
SYSTEMS