Variable Tip-Speed-Ratio Wind Turbine Control
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Solution Overview
Problem
Wind turbines often experience power loss in the variable wind speed region due to torque saturation occurring before maximum rotor speed, leading to suboptimal energy production.
Innovation Solution
A system and method for continuously adjusting the tip-speed-ratio set point of wind turbines to operate along torque constraint boundaries, defining regions of unsaturated and saturated torque ranges, and using sliding-mode control to maximize power output by adjusting the tip-speed-ratio based on torque output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a fixed tip-speed-ratio control is used, then the control system is simple and reliable, but power production is reduced due to torque saturation occurring before maximum rotor speed
Solution Approach 1:
The patent applies dynamics by transitioning from a fixed tip-speed-ratio control to a variable tip-speed-ratio control system. The controller dynamically adjusts the tip-speed-ratio setpoint based on real-time torque measurements, allowing the system to adapt to changing operating conditions and avoid torque saturation, thereby maximizing power production across varying wind speeds.
Solution Approach 2:
The patent changes the control parameter from a fixed tip-speed-ratio to a variable tip-speed-ratio that is continuously adjusted based on torque output. By monitoring torque and modifying the tip-speed-ratio setpoint accordingly, the system optimizes power capture while preventing early torque saturation, directly addressing the productivity improvement.
2Productivity
If the rotor speed is increased to maximize power capture, then energy production improves, but torque saturation occurs earlier reducing efficiency
Solution Approach 1:
The patent implements feedback control by continuously monitoring the torque output of the wind turbine and using this information to adjust the tip-speed-ratio setpoint. This closed-loop feedback mechanism allows the controller to detect approaching torque saturation and adjust operating parameters accordingly, preventing energy loss while maximizing power capture.
Solution Approach 2:
Instead of directly controlling rotor speed to maximize power capture (which causes torque saturation), the patent inverts the approach by controlling the tip-speed-ratio based on torque feedback. This indirect control method allows the system to achieve optimal power capture while avoiding the harmful effect of torque saturation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances power production in the variable wind speed region, increasing annual energy production (AEP) by avoiding early torque saturation and optimizing energy capture.
Implementation Method 1
The rotor blades capture kinetic energy of wind using known airfoil principles
Data Source
Figure 1~2
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AI summary
The present subject matter is directed to a system and method for operating a wind turbine 10 so as to increase power production by utilizing variable tip-speed-ratio control. In one embodiment, the method includes defining a first operating region 309 associated with an unsaturated torque range and a second operating region 310 associated with a saturated torque range. Further, the method includes monitoring a torque output of the wind turbine 10. The method also includes continuously adjusting a tip-speed-ratio set point of the wind turbine 10 so as to operate the wind turbine 10 along a torque constraint boundary 312 of the first and second operating regions 309,310.