Wind Power Rotor Control for Series-Compensated Oscillation Damping
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Solution Overview
Problem
Conventional methods for controlling sub-synchronous oscillations in wind power plants with series compensation are complex and ineffective, requiring detection of multiple frequency components and complex controller structures, which are not adaptable to weak power grids with varying series compensation degrees.
Innovation Solution
A method involving a filter to extract dynamic small signals from relevant parameters, using a PID negative feedback controller and power oscillation damping (POD) controller to feedforward control parameters to rotor voltage and current controllers, along with phase and amplitude compensations, to suppress power, sub-synchronous, and rotor current loop oscillations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional methods for suppressing sub-synchronous oscillation are used, then oscillation control is attempted, but the control structure becomes complex and requires detection of multiple frequency components
Solution Approach 1:
The patent extracts only the necessary sub-synchronous frequency components (positive and negative sequence) from the complex multi-frequency spectrum, focusing control effort on the critical oscillation modes rather than attempting to control all frequency components simultaneously. This simplifies the controller structure while maintaining effectiveness.
Solution Approach 2:
The unified controller designed in the patent performs multiple functions: it detects sub-synchronous oscillations, identifies their frequency components, and applies appropriate damping control across different operating conditions and series compensation degrees, replacing the need for multiple specialized controllers.
2Reliability
If conventional methods detect and identify all sub-synchronous voltage and current frequency information, then oscillation control is achieved, but the detection and control complexity increases significantly
Solution Approach 1:
The patent extracts only the critical sub-synchronous frequency components (positive and negative sequence components) from the full spectrum of voltage and current signals, rather than detecting and analyzing all frequency components. This reduces measurement and detection complexity while maintaining control accuracy.
3Adaptability or versatility
If a comprehensive controller for all sub-synchronous oscillations is designed, then all frequency components can be controlled, but the controller structure and parameter design become complex
Solution Approach 1:
The patent designs a unified sub-synchronous oscillation suppression controller that handles both positive and negative sequence components through a single integrated structure, rather than requiring separate controllers for each frequency component. This reduces overall controller complexity while maintaining comprehensive coverage.
4Adaptability or versatility
If conventional control methods are used in weak power grids with different series compensation degrees, then control is attempted, but adaptability to different grid conditions is poor
Solution Approach 1:
The patent implements dynamic adaptation mechanisms that allow the controller parameters and control strategy to automatically adjust based on the actual series compensation degree and grid conditions, rather than using fixed parameters designed for specific compensation levels. This enhances adaptability across different weak grid scenarios.
Data Source
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AI summary
A method, an apparatus, a device and a system for controlling an oscillation damping caused by a series compensation for a wind power plant are provided. The method includes: extracting, a first dynamic small signal from first relevant parameters causing power oscillation, inputting the first dynamic small signal to a PID controller, and feeding an output control parameter from the PID to a rotor voltage controller as a first feedforward term; obtaining, according to second relevant parameters causing sub-synchronous oscillation, a virtual voltage, and feeding into a rotor voltage controller as a second feedforward term; and extracting a third dynamic small signal from third relevant parameters causing the oscillation of a rotor current loop and then performing phase and amplitude compensations on the third dynamic small signal, and feeding the output of the POD controller into the given position of a rotor current controller as a third feedforward term.