Doubly Fed Induction Machine: Modeling And Control For Wind Energy Generation

This book will be focused on the modeling and control of the DFIM based wind turbines. In the first part of the book, the mathematical description of different basic dynamic models of the DFIM will be carried out. It will be accompanied by a detailed steady-state analysis of the machine. After that, a more sophisticated model of the machine that considers grid disturbances, such as voltage dips and unbalances will be also studied. The second part of the book surveys the most relevant control strategies used for the DFIM when it operates at the wind energy generation application. The control techniques studied, range from standard solutions used by wind turbine manufacturers, to the last developments oriented to improve the behavior of high power wind turbines, as well as control and hardware based solutions to address different faulty scenarios of the grid. In addition, the standalone DFIM generation system will be also analyzed.

GONZALO ABAD, PhD, is an Associate Professor in the Electronics Department at the Mondragon University, where he teaches modeling, control, and power electronics.

JESUS LOPEZ, PhD, is an Assistant Professor in the Electrical and Electronic Engineering Department of the Public University of Navarra, where he teaches subjects related to the electrical drives and the processing of electrical power in wind turbines.

MIGUEL RODRIGUEZ, PhD, is the Power Electronics Systems Manager at Ingeteam Technology, responsible for developing new power electronics for transmission and distribution grid applications.

LUIS MARROYO, PhD, is an Associate Professor in the Electrical and Electronic Engineering Department of the Public University of Navarra, where he teaches courses on electrical machines and power electronics.

GRZEGORZ IWANSKI, PhD, is an Associate Professor in the Institute of Control and Industrial Electronics at the Warsaw University of Technology, where he teaches courses on power electronics drives and conversion systems.

1. Introduction to the Wind Energy Generation Systems.

1.1 Introduction.

1.2 Basic concepts of a fixed speed wind turbine (FSWT).

1.3 Variable Speed Wind Turbines (VSWT).

1.4 Wind energy generation system based on DFIM VSWT.

1.5 Grid Code Requirements.

1.6 Voltage dips and LVRT.

1.7 VSWT based on DFIM manufacturers.

1.8 Introduction to the next chapters.

1.9 References.

2. Back-to-Back Power Electronic Converter.

2.1 Introduction.

2.2 Back to Back Converter based on Two Level VSC Topology.

2.3 Multilevel VSC Topologies.

2.4 Control of Grid Side System.

2.5 Summary.

2.6 References.

3. Steady-State of the Doubly Fed Induction Machine.

3.1 Introduction.

3.2 Equivalent Electric Circuit at Steady-State.

3.3 Operation Modes Attending to the Speed and Power Flows.

3.4 Per Unit Transformation.

3.5 Steady-State Curves: Performance Evaluation.

3.6 Design Requirements for the DFIM in Wind Energy Generation Applications.

3.7 Summary.

3.8 References.

4. Dynamic Modeling of the Doubly Fed Induction Machine.

4.1 Introduction.

4.2 Dynamic Modeling of the DFIM.

4.3 Summary.

4.4 References.

5. Testing of the DFIM.

5.1 Introduction.

5.2 Off-line Estimation of the DFIM Model Parameters.

5.3 Summary.

5.4 References.

6. Analysis of the DFIM under Voltage Dips.

6.1 Introduction.

6.2 Electromagnetic Force Induced in the Rotor.

6.3 Normal Operation.

6.4 Three-phase Voltage Dips.

6.5 Asymmetrical Voltage Dips.

6.6 Influence of the Rotor Currents.

6.7 DFIM equivalent Model during Voltage Dips.

6.8 Summary.

6.9 References.

7. Vector Control Strategies for grid connected DFIM Wind Turbines.

7.1 Introduction.

7.2 Vector Control.

7.3 Small Signal Stability of the vector control.

7.4 Vector Control Behavior under Unbalance Conditions.

7.5 Vector Control Behavior under Voltage Dips.

7.6 Control Solutions for Grid Disturbances.

7.7 Summary.

7.8 References.

8. Direct Control of the Doubly Fed Induction Machine.

8.1 Introduction.

8.2 Direct Torque Control (DTC) of the Doubly Fed Induction Machine.

8.3 Direct Power Control (DPC) of the Doubly Fed Induction Machine.

8.4 Predictive Direct Torque Control (P-DTC) of the Doubly Fed Induction Machine at Constant Switching Frequency.

8.5 Predictive Direct Power Control (P-DPC) of the Doubly Fed Induction Machine at Constant Switching Frequency.

8.6 Multilevel Converter based Predictive Direct Power and Direct Torque Control, of the Doubly Fed Induction Machine at Constant Switching Frequency.

8.7 Control solutions for grid voltage disturbances, based on direct control techniques.

8.8 Summary.

8.9 References.

9. Hardware solutions for LVRT.

9.1 Introduction.

9.2 Grid Codes Related to LVRT.

9.3 Crowbar.

9.4 Braking Chopper.

9.5 Other Protection Techniques.

9.6 Summary.

9.7 References.

10. Complementary Control Issues: Estimator Structures and Start-up of Grid Connected DFIM.

10.1 Introduction.

10.2 Estimator and Observer Structures.

10.3 Start-up of the Doubly Fed Induction Machine based Wind Turbine.

10.4 Summary.

10. References.

11. Stand-alone DFIM based Generation Systems.

11.1 Introduction.

11.2 Mathematical Description of the Stand-alone DFIM System.

11.3 Stator Voltage Control.

11.4 Synchronization before grid connection by superior PLL.

11.5 Summary.

11.6 References.

12. New Trends on Wind Energy Generation.

12.1 Introduction.

12.2 Future challenges on wind energy generation: what must be innovated.

12.3 Technological trends: How can be achieved.

12.4 Summary.

12.5 References.

1. Space Vector Representation.

1.1 Space Vector Notation.

1.2 Transformations to different reference frames.

1.3 Power expressions.

2. Dynamic Modeling of the DFIM Considering the Iron Losses.

1.4 Model.

1.5 dq Model.

1.6 State-Space Representation of αβ Model.

1.7 References.