Wind Turbine Negative Sequence Current Control
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Solution Overview
Problem
Existing wind turbine systems face challenges in effectively controlling negative sequence currents caused by imbalances in the power grid, which can negatively impact both the power grid and the wind turbine system, and prior solutions do not provide an optimal relationship between voltage and current.
Innovation Solution
A system and method that utilizes a negative sequence regulator programmed in a controller to determine the negative sequence component of electrical conditions, calculate a desired current response, and generate a control command for the power converter to achieve a desired inductive relationship between voltage and current, similar to a directly-connected synchronous machine.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the control system attenuates the negative sequence component of current to reduce equipment duty, then equipment stress is reduced, but the power system connection quality deteriorates
Solution Approach 1:
The patent converts the harmful negative sequence voltage component into a beneficial control signal. By detecting the negative sequence voltage and using it to generate compensating current commands, the system transforms the harmful grid imbalance into a useful control input that achieves both equipment protection and power quality improvement simultaneously
2Stability of the object's composition
If a negative sequence regulator is implemented to achieve desired voltage-current relationship, then grid stability is improved, but device complexity increases
Solution Approach 1:
The negative sequence regulator is integrated into the existing power converter control system, allowing the same control platform to handle both positive sequence (normal operation) and negative sequence (unbalance compensation) functions. This multi-functionality approach achieves grid stability improvement without proportionally increasing device complexity
Solution Approach 2:
The system implements feedback control by continuously monitoring the negative sequence voltage component and adjusting the current injection accordingly. The regulator compares the desired current response with the actual response and generates corrective control commands, achieving stable grid operation through closed-loop control rather than open-loop complexity
Data Source
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AI summary
The present disclosure is directed to a system and method for controlling an electrical power system 200 connected to a power grid 242. The method includes determining, via a negative sequence regulator 302 programmed in a controller 202 of the electrical power system 200, a negative sequence component of at least one electrical condition of the electrical power system 200. Further, the method includes determining a desired current response based on the negative sequence component of the at least one electrical condition of the electrical power system 200. Thus, the method also includes determining a control command for the power converter 210 as a function of the desired current response so as to achieve a desired relationship between a voltage condition in the power grid 242 and the negative sequence component of the electrical condition of the electrical power system 200.