Chapter
1.4.4 The Application of New Power Semiconductor Devices
1.4.5 More Advanced Grid Integration Control
1.4.6 Configurations of Wind Power Plants
1.5 The Topics of This Book
2 Basics of Wind Power Generation System
2.2.1 Fixed-Speed Concept
2.2.2 Variable-Speed Concept with Partial Power Converters
2.2.3 Variable-Speed Concept with Full-Scale Power Converters
2.2.4 Hardware Protection Methods
2.3 Variable-Speed Wind Turbine
2.3.3 Overall Control Scheme
2.3.4 Operational Range of Wind Turbine Systems
2.3.5 Wind Turbine Operation Around Cut-In Speed
2.3.6 MPPT Operation of Wind Turbine
2.3.7 Wind Turbine Operation Around Cut-off Speed
2.4 Control of Power Converter
2.4.1 Control of DFIG Power Converter
2.4.2 Control of PMSG Power Converter
2.4.3 Control of SCIG Power Converter
2.5 Wind Power Transmission
2.5.4 Unbalanced Grid Voltage
2.5.5 Grid Harmonic Voltage
3 Grid Codes for Wind Power Generation Systems
3.2 Grid Code Requirements Under Normal Operation
3.2.1 Frequency and Voltage Deviation
3.2.2 Active Power Control
3.2.3 Reactive Power Control
3.2.4 Inertial Control and Power System Stabilizer Function
3.3 Grid Code Requirements Under Non-Ideal Grid
3.3.1 Low Voltage Ride-Through Requirement
3.3.2 High Voltage Ride-Through Requirement
3.3.3 Recurring Fault Ride-Through Requirement
3.3.4 Unbalanced Grid Operation
3.3.5 Harmonic Distortion Requirements
3.4 Grid Codes for Distributed Wind Power Generation
3.4.2 Active and Reactive Power Control
3.4.3 Operation under Grid Faults
PART II Modeling and Control of DFIG
4 Modeling of DFIG Wind Power Systems
4.2 Steady-State Equivalent Circuit of a DFIG
4.2.1 Steady-State Equivalent Circuit of a DFIG
4.3 Dynamic Model of a DFIG
4.4 Modeling of the Converter
4.4.1 Steady-State Equivalent Circuit of the Converter
4.4.2 abc Model with L Filter
4.4.3 dq Model with L Filter
4.4.4 dq Model with LCL Filter
4.4.5 Model of the PWM Modulator
5 Control of DFIG Power Converters
5.2 Start-Up Process of the DFIG System
5.3.2 Grid Synchronization
5.3.4 Simplified Control Model in s-Domain
5.4 Rotor-Side Converter in Power-Control Mode
5.4.3 Control Model in s-Domain
5.4.5 Test Results from a 1.5 MW DFIG WPS
5.5 Rotor-Side Converter in Speed-Control Mode
5.5.1 Control Target [7, 9, 10]
5.5.2 Grid Synchronization
5.5.4 Control Model in s-Domain
5.6 Rotor-Side Converter in Starting Mode
5.6.2 Grid Synchronization
5.6.4 Control Model in s-Domain
5.7 Control-Mode Switching
5.7.1 From Starting Mode to Power-Control or Speed-Control Mode
5.7.2 Between Power-Control Mode and Speed-Control Mode
PART III Operation of DFIG Under Distorted Grid Voltage
6 Analysis of DFIG Under Distorted Grid Voltage
6.2.1 Model of GSC under Distorted Grid Voltage
6.2.2 Influence on Grid Current
6.2.3 Influence on Output Active and Reactive Powers
6.2.4 Influence on the DC-Bus Voltage
6.2.5 Example of a 1.5 MW DFIG WPS
6.3 Influence on DFIG and RSC
6.3.1 Model of DFIG and RSC under Distorted Grid Voltage
6.3.2 Influence on Rotor Current
6.3.3 Influence on Stator Current
6.3.4 Influence on Active and Reactive Powers
6.3.5 Influence on Electromagnetic Torque
6.3.6 Influence on DC-Bus Voltage
6.3.7 Example of a 1.5 MW DFIG WPS
6.4 Discussion on Different Controller Parameters
6.5 Discussion on Different Power Scales
7 Multiple-Loop Control of DFIG Under Distorted Grid Voltage
7.2.3 System Model with Harmonic Suppression Loop
7.3.3 System Model and Control Effect
7.3.5 Simulation and Test Results
7.4 Influence on the Fundamental Current Loop
7.4.1 Influence on the Stability and Dynamic Response
7.4.2 Simulation and Test Results
8 Resonant Control of DFIG Under Grid Voltage Harmonics Distortion
8.2.1 Mathematical Model of a Resonant Controller
8.2.2 Resonant Controller in dq Frames
8.3 Stator Current Control Using Resonant Controllers
8.3.3 Control Model in dq Frame
8.3.5 Experimental Results
8.4 Influence on Normal Control Loop
8.4.2 Stability of the System
8.4.3 Dynamic Performance
8.5 Design and Optimization of Current Controller
8.5.1 Systematic Design Procedure
8.5.2 Phase Compensation Methods for the Resonant Controller
8.5.3 Simulation Results of Phase Compensation
9 DFIG Under Unbalanced Grid Voltage
9.2 RSC and DFIG Under Unbalanced Grid Voltage
9.2.1 Rotor and Stator Currents
9.2.2 Active and Reactive Powers
9.2.3 Electromagnetic Torque
9.2.4 Simulation on the Influence of Grid Voltage Unbalance
9.3 GSC Under Unbalanced Grid Voltage
9.3.2 Active Power of the Generator
9.3.3 DC-Bus Current and Voltage
9.4 Control Limitations Under Unbalanced Grid Voltage
9.4.1 Control Limitations of RSC
9.4.2 Control Limitations of GSC
9.4.3 DC-Bus Capacitor Current and Voltage
10 Control of DFIG Wind Power System Under Unbalanced Grid Voltage
10.3 Stator Current Control With Resonant Controller
10.3.2 Analysis of the Controller
10.3.3 Experiment and Simulation Results
10.4 DC Voltage Fluctuation Control by GSC
10.4.1 Challenges in the Control of GSC
10.4.2 DC Current Calculation
10.4.5 Elimination of Third-Order Harmonic Current Introduced by Capacitor Current Control
10.4.6 Experimental Results
PART IV Grid Fault Ride-Through of DFIG
11 Dynamic Model of DFIG Under Grid Faults
11.2 Behavior During Voltage Dips
11.2.1 Equivalent Circuits of DFIG under Voltage Dips
11.2.2 With Rotor Open Circuit
11.2.3 With Normal Vector Control
11.2.4 With Rotor-Side Crowbar
11.2.5 Non-Instant Voltage Dips
11.3 DFIG Behavior During Voltage Recovery
11.3.1 During Instant Voltage Recovery
11.3.2 Voltage Recovery in Power Systems
11.3.3 During Three-Phase Fault Recovery
11.3.4 During Three-Phase-To-Ground Fault Recovery
11.3.5 During Asymmetrical Fault Recovery
11.4 Under Recurring Grid Faults
11.4.1 During Symmetrical Recurring Fault
11.4.2 Influence of the First Dip Level
11.4.3 Influence of the Grid Fault Angle
11.4.4 Influence of the Durations between Two Faults
11.4.5 Asymmetrical Recurring Faults
11.4.6 Experiments of DFIG under Recurring Grid Faults
12 Grid Fault Ride-Through of DFIG
12.2 PLL Under Grid Faults
12.2.1 SRF-PLL under Grid Faults
12.2.2 SRF-PLL with a Low Pass Filter
12.2.3 SRF-PLL with Negative/Positive-Sequence Separation
12.2.4 Test Results of PLL with Sequence Separation
12.3 FRT Strategies for DFIG Based on Improved Control
12.3.1 Demagnetizing Current Control
12.3.2 Flux Linkage Tracking Control
12.3.3 Feedforward Control
12.4 FRT Strategies Based on Hardware Solutions
12.4.1 Rotor-Side Crowbar
12.4.3 Series Dynamic Breaking Resistor
12.4.4 Dynamic Voltage Restorer
12.5 Recurring Fault Ride Through
12.5.1 Challenge for the Recurring Grid Fault Ride Through
12.5.2 Control Target for Recurring Fault Ride Through
12.5.3 Control Implication
12.5.5 Simulation and Test Results
13 Thermal Control of Power Converter in Normal and Abnormal Operations
13.1 Loss Model of Power Converter
13.1.1 Loss Model of a Power Semiconductor Device
13.1.2 Loss Model of Grid-Side Converter
13.1.3 Loss Model of Rotor-Side Converter
13.2 Thermal Model of Power Converter
13.2.1 Thermal Impedance in Power Module
13.2.2 Junction-Temperature Calculation
13.3 Thermal Loading During Normal Operation
13.3.1 DFIG System in Case Study
13.3.2 Loss Breakdown at Various Loading Conditions
13.3.3 Thermal Profile at Various Loading Conditions
13.4 Thermal Loading in Abnormal Operation
13.4.1 Grid Codes Requirements
13.4.2 Operation Behavior under Voltage Dips
13.4.3 Loss Distribution and Thermal Behavior During LVRT
13.5 Smart Thermal Control by Reactive Power Circulation
13.5.1 Effects of Reactive Power on Current Characteristic
13.5.2 Thermal Performance Improvement by Reactive Power Control
14.2 Scheme of the DFIG Test Bench
14.3 The Caged Motor and its Driving Inverter
14.4.2 Hardware Design of the GSC
14.4.3 Control Design of the GSC
14.4.4 Testing of the GSC
14.4.5 Hardware Design of the RSC
14.4.6 Control Design of the RSC
14.4.7 Testing of the RSC
14.6.1 Demands of the Grid Emulator
14.6.4 Testing of the Grid Emulator
14.6.5 Test Waveforms of Grid Emulator
14.7 Communications and Up-Level Control
14.8 Start-Up and Protection of The System
14.8.1 Start-Up of the System
14.8.2 Shutdown of the System
14.8.3 Overcurrent Protection of the System
14.8.4 Overvoltage Protection of the System
A.1 Flux Equations in 𝜶𝜷 Reference Frame
A.2 Typical Parameters of a DFIG
Advanced Control of Doubly Fed Induction Generator for Wind Power Systems
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