Wind Turbine Rotor Speed Control for High Wind Energy Capture
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Solution Overview
Problem
Conventional wind turbines shut down above a certain wind speed, leading to loss of energy capture and grid stability issues due to high turbulence and the time required for recovery, as they are designed to prevent damaging loads but result in inefficient energy production and abrupt power changes.
Innovation Solution
A control system that adjusts the rotor/generator speed set point based on the standard deviation of measured operating parameters to maintain operation below a certain threshold, allowing the turbine to continue running during high wind speeds and turbulence by selecting a set point a predetermined number of standard deviations away from the over speed limit, thereby reducing loading and maintaining energy capture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the wind turbine shuts down above a certain wind speed to prevent damaging loads, then the reliability of the turbine is improved, but the energy capture is reduced
Solution Approach 1:
The invention changes the control parameter from binary shutdown/non-shutdown to continuous active load reduction by adjusting rotor speed. Instead of shutting down the turbine when wind speed exceeds the cut-out threshold, the control system actively reduces the rotor speed setpoint to limit aerodynamic loads while maintaining operation. This transforms the discrete shutdown decision into a continuous parameter adjustment that preserves energy capture while ensuring reliability.
2Reliability
If the wind turbine shuts down during high turbulence, then the turbine is protected from damaging loads, but the grid stability is compromised due to abrupt power changes
Solution Approach 1:
The invention ensures continuous operation of the turbine during high turbulence events by maintaining active load reduction control throughout the event. The rotor speed setpoint is continuously adjusted based on real-time turbulence conditions, ensuring smooth and continuous power output to the grid. This eliminates abrupt shutdowns and subsequent restart delays, maintaining continuous useful action both for turbine protection and grid stability.
Solution Approach 2:
The control system uses feedback from turbulence measurements and power output monitoring to continuously adjust the rotor speed setpoint. When turbulence is detected, the system responds by reducing rotor speed to limit loads, and maintains this adjusted setpoint throughout the turbulence event. This closed-loop feedback control ensures both turbine protection and smooth power delivery to the grid, preventing abrupt changes that would compromise stability.
3Reliability
If the wind turbine uses a conservative cut-out strategy, then the turbine avoids damaging loads, but the time required for recovery to normal power production increases
Solution Approach 1:
The invention replaces the static cut-out strategy with a dynamic active load reduction approach. Instead of shutting down at a fixed wind speed threshold and requiring a cooldown period before restart, the system dynamically adjusts the rotor speed setpoint based on real-time turbulence conditions. When turbulence subsides, the control system can immediately begin increasing the rotor speed setpoint back toward normal operating levels, eliminating the fixed recovery delay and enabling faster return to full power production.
Data Source
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AI summary
An apparatus and method for extending the power-capture region of a wind turbine (100) during certain operating conditions is disclosed. The actual set point of an operational parameter is selected so as to be maintained at a predetermined number of standard deviations away from an operating limit during certain operating conditions. For example, the operational parameter may be a rotor/generator speed and the operating condition may be a mean wind speed that exceeds a predetermined wind speed.