Wind Turbine Torque Control During Grid Dips
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Solution Overview
Problem
Wind energy installations with variable rotation speed are vulnerable to grid disturbances, leading to disconnection from the grid during voltage dips, resulting in reduced power availability and potential drive train damage due to oscillations and torque peaks.
Innovation Solution
A control device with a detector for grid dips, a torque transmitter, and an initializer that sets the torque control unit to a specific value, initializing the integrator to zero and varying weighting factors to prevent saturation, allowing the system to maintain control margin and damp oscillations effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the wind energy installation remains connected to the grid during voltage dips, then power availability is maintained, but drive train damage risk increases due to oscillations and torque peaks
Solution Approach 1:
The control device performs preliminary actions by detecting voltage dips early and initializing the torque control unit before the dip ends. The detector identifies the start of voltage dips, and the initializer prepares the torque control unit with appropriate set points in advance, allowing the system to respond proactively rather than reactively to prevent drive train damage while maintaining grid connection
Solution Approach 2:
The control device implements feedback by continuously monitoring grid voltage through the detector and adjusting torque control unit parameters based on real-time voltage conditions. The feedback loop enables the system to adapt torque set points and control margins dynamically, maintaining stability during voltage dips while preventing excessive torque peaks that could damage the drive train
2Speed
If the torque control unit responds dynamically to voltage dip end, then oscillations are amplified causing torque peaks, but slower response allows drive train damage
Solution Approach 1:
The initializer prepares the torque control unit in advance by setting appropriate torque set points before the voltage dip ends. This preliminary action ensures that when voltage returns, the control unit is already configured to damp oscillations rather than amplify them, achieving fast response without torque peaks
Solution Approach 2:
The control device changes control parameters dynamically by adjusting torque set points and control margins based on voltage dip detection. The initializer modifies the torque control unit parameters specifically during voltage dips, changing the system's dynamic characteristics to prevent oscillation amplification while maintaining rapid response capability
3Reliability
If conventional closed-loop control is used, then normal operation is maintained, but saturation occurs during voltage dips reducing control effectiveness
Solution Approach 1:
The control device implements dynamics by making the torque control unit adaptable to different operating conditions. The initializer dynamically adjusts control parameters based on voltage dip detection, allowing the system to transition from conventional closed-loop control to a specialized control mode during voltage dips, preventing saturation and maintaining control effectiveness
Solution Approach 2:
The control device changes parameters by modifying torque set points and control margins during voltage dips. The initializer adjusts these parameters specifically when voltage dips are detected, preventing the torque control unit from saturating and maintaining adequate control margin throughout the voltage dip event
Data Source
AI summary
A wind energy installation control device includes a wind rotor, a generator driven by the wind rotor, a torque control unit configured to control a torque of the generator, and a control system. The control system includes a detector configured to identify a grid dip and an end of the grid dip, a residual torque transmitter configured to provide a set point for a torque of the generator after identification of the grid dip, and an initializer configured to initialize a component of the torque control unit at the set point. Accordingly, upon return of grid power after a grid dip, the vibration behavior of a wind power system can be significantly improved. Overload of a drive train upon return of grid voltage can thus be reduced.