Variable frequency resonant controller for load reduction in wind turbines

• Published in: Control engineering practice Vol. 66; pp. 76 - 88
• Main Authors: Castro, Rafael S., Salton, Aurélio T., Flores, Jeferson V., Kinnaert, Michel, Coutinho, Daniel F.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.09.2017
• Subjects: Internal model principle; Periodic disturbance rejection; Resonant controller; Robust control; Wind turbine control; Robust control; Internal model principle; Periodic disturbance rejection; Resonant controller; Wind turbine control
• ISSN: 0967-0661; 1873-6939
• DOI: 10.1016/j.conengprac.2017.06.007

While most loads on wind turbines are originated from wind speed fluctuations, they show a periodic nature with a time-varying frequency proportional to the turbine rotation. This paper exploits this relation and proposes a modified Resonant Controller able to attenuate these frequency-varying periodic disturbances. The resulting controller is designed for both partial and full load wind speed conditions, therefore, it is able to reject periodic loads even when the wind turbine system is subject to changes in the operating rotation speed. Furthermore, a novel piecewise linear representation of the system is presented allowing a systematic design procedure, based on Linear Matrix Inequalities, in order to compute the control parameters. Simulation results in a 2.5MW large scale three-bladed wind turbine illustrate the proposed method, which is able to reduce the root mean value of blade load up to 12 times when compared to a traditional LPV controller. •Proposes a Frequency-Varying Resonant Controller for disturbance rejection.•Ensures power extraction and load reduction for both below/above-rated wind regimes.•A novel linear-piecewise model of the wind turbine is proposed.•LMIs are devised to ensure robust stability and H2 performance.•H∞-norm bound approach to deal with nonperiodic disturbance components.