Modelling, control and performance analysis of a 6 MW wind turbine

Abstract

Rapid growth in wind generation is accompanied with increasingly large wind turbine sizes. While the large rotor size of utility-scale wind turbines can deliver greater economic benefits, the challenges associated with control system development can get significantly amplified with increases in turbine rotor spans. The aim of this paper is to identify and quantify the trade-offs involved with controlling various conflicting control objectives, such as power output maximisation and mitigation of blade and tower loading, in utility-scale wind turbines. In order to do this, first a comprehensive high-fidelity simulation model of a 6 MW wind turbine is developed. This is followed by the development of a series of rule-based, conventional PI and modern LQR controllers. Each of the controllers is designed separately for various control objectives, both independently and as combinations of control objectives. The controllers are validated on high-fidelity wind turbine model under realistic wind and turbulence conditions. A grading scheme is proposed to score the performance of each controller in meeting control objectives when the wind turbine is operated in a range of wind conditions. As a result, the overall performance of various control methods and the computational cost considerations for the control systems development in large utility-scale wind turbines are established.