Control design for load reduction on wind turbine system

Masteroppgave i mekatronikk MAS500 2011 – Universitetet i Agder, GrimstadThe wind power industry is currently the fastest growing renewable energy sector throughout the world. This requires the technical expertise among engineers and researchers in the wind energy field to find technical solutions which do not slow down this process. Since the technology is being developed at such a rapid rate, the industry is facing many challenging problems, especially among systems and control researchers. To ensure an economically competitive wind power production, the trend is to increase the turbine size while at the same time minimize material usage. These factors result in increasing fatigue loads, which need to be accounted for by a well defined control design. In this work, the basic theories of wind turbines are reviewed firstly before proceeding with modeling, simulation, and controls implementation. What is suggested as a means of load reduction is firstly a Disturbance Accommodating Control (DAC) approach. This is then compared with the well-known Linear Quadratic Gaussian (LQG) controlling method. To improve the robustness of the LQG, an additional Loop Transfer Recovery (LTR) procedure will be implemented and compared with the results from the LQG. The main focus in this work is to use these modern control theories to reduce the torque variations by using speed control with collective blade pitch adjustments. Simulations show that better load reduction can be obtained by the dynamic compensator extracted from the LTR procedure than with a regular LQG regulator