Voltage-Source Wind Turbine Control for Grid-Stable Power Decoupling
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Solution Overview
Problem
Existing wind power generation technologies face challenges in effectively controlling voltage source wind turbines, particularly in maintaining grid stability and managing the coupling between active and reactive power.
Innovation Solution
A method and apparatus for controlling a voltage source type wind turbine, which involves obtaining active power deviations through PID operations, determining virtual angular frequency and inner potential phases, and using virtual impedance to modulate voltages, thereby controlling the injection voltage at the point of common coupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional control methods are used for voltage source wind turbines, then the control structure is simple, but grid stability deteriorates and coupling between active and reactive power increases
Solution Approach 1:
The control method segments the complex control problem into distinct functional modules: virtual impedance module for decoupling active and reactive power, virtual PSS module for damping oscillations, and coordinated control loops. This modular segmentation allows each module to address specific stability issues independently while working together to achieve overall grid stability.
Solution Approach 2:
The patent introduces virtual impedance and virtual PSS as intermediary control elements that mediate between the wind turbine and the grid. These virtual components act as buffers that decouple the coupling between active and reactive power while providing additional damping, thereby improving grid stability without requiring direct modification of the physical turbine structure.
2Adaptability or versatility
If conventional control is used, then the control implementation is simple, but the coupling between active power and reactive power increases
Solution Approach 1:
The control method dynamically adjusts virtual impedance parameters and virtual PSS parameters based on operating conditions. By changing these control parameters adaptively, the system achieves effective decoupling of active and reactive power while maintaining simplicity in the overall control structure. The parameter changes allow the controller to respond to different grid conditions without increasing structural complexity.
3Reliability
If dynamic voltage control is implemented, then grid stability improves, but the response time for deviation suppression decreases
Solution Approach 1:
The virtual PSS is designed with preliminary action characteristics, where damping signals are generated in advance based on predicted oscillation trends. The control algorithm anticipates potential deviations and applies corrective actions before full deviations occur, thereby maintaining grid stability while reducing the actual response time needed for suppression.
Solution Approach 2:
The control system implements multi-loop feedback mechanisms including voltage feedback, current feedback, and power feedback. These feedback loops continuously monitor system state and adjust control outputs in real-time, enabling rapid deviation suppression. The coordinated feedback from multiple sources allows the system to respond quickly to disturbances while maintaining overall stability.
Data Source
AI summary
The present disclosure provides a control method and control apparatus for a voltage source-type wind turbine. The control method comprises: performing a proportional-integral-derivative operation on a deviation between a DC bus voltage measurement value and DC bus voltage reference value of a wind turbine to obtain an active power deviation; determining a virtual angular frequency deviation on the basis of the active power deviation; determining a virtual internal potential phase on the basis of the virtual angular frequency deviation; obtaining a d-axis virtual impedance output and an q-axis virtual impedance output by means of inputting a grid-connected current in a dq coordinate system to a virtual impedance module; on the basis of the virtual angular frequency deviation, a reactive power setting value and reactive power measurement value of the wind turbine, a rated voltage amplitude of a grid, the d-axis virtual impedance output and the q-axis virtual impedance output, determining a d-axis component and q-axis component of a modulation voltage; and controlling an injection voltage of a grid-connected point of the wind turbine according to the virtual internal potential phase and the d-axis component and q-axis component of the modulation voltage.