Wind Turbine Generator Speed Control for Low Wind Efficiency
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Solution Overview
Problem
Conventional wind turbines operate inefficiently at low wind speeds due to high tip-speed-ratio (TSR), resulting in wasted energy and reduced annual energy production (AEP).
Innovation Solution
A method and system that monitor wind speed and reduce the generator speed limit when wind speeds drop below a threshold, optimizing the tip-speed-ratio by transferring reactive power to a compensation device, thereby increasing power production during low wind conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the wind turbine operates at minimum speed limit during low wind speeds, then the cut-in speed requirement is met, but the tip-speed-ratio becomes excessively high resulting in energy waste and reduced efficiency
Solution Approach 1:
The patent dynamically adjusts the generator speed limit parameter based on wind speed conditions. When wind speed drops below a threshold, the controller reduces the generator speed limit from the normal minimum speed limit to a lower value, thereby optimizing the tip-speed-ratio and reducing energy waste while still meeting operational requirements
2Loss of energy
If the generator speed limit is reduced to optimize TSR during low wind speeds, then energy efficiency improves, but the reactive power requirement from the DFIG increases
Solution Approach 1:
The patent introduces a reactive power compensation device as an intermediary to handle the increased reactive power demand. When the generator speed limit is reduced and reactive power requirement increases, the compensation device supplies the additional reactive power, relieving the burden on the DFIG and enabling the optimized speed operation
3Stress or pressure
If the RSC operates at higher voltage to maintain minimum turbine speed, then the voltage limit imposed by RSC is satisfied, but the operating slip increases reducing overall system efficiency
Solution Approach 1:
The patent implements dynamic control of the generator speed limit based on real-time wind speed measurements. Instead of maintaining a fixed minimum speed limit, the system adaptively adjusts the speed limit to match prevailing wind conditions, thereby optimizing the operating point and improving overall system efficiency while still meeting voltage requirements
Data Source
AI summary
A method for operating a wind turbine power system that supplies real and reactive power to a grid includes operating a generator of the wind turbine power system up to a first speed limit. The method also includes monitoring a wind speed at the wind turbine power system. When the wind speed drops below a predetermined threshold, the method includes reducing the first speed limit of the generator to a reduced speed limit of the generator. Further, the method includes operating the generator at the reduced speed limit for as long as the wind speed remains below the predetermined threshold so as to optimize a tip-speed-ratio of the wind turbine power system during low wind speeds, thereby increasing power production of the wind turbine power system at low wind speeds.