Active Pitch Control in Larger Scale Fixed Speed Horizontal Axis Wind Turbine Systems Part II: Non-Linear Controller Design

Abstract

This paper considers non-linear control of fixed speed wind turbines in above rated wind speed, using blade pitch angle control and with special emphasis on differential geometric theory. A non-linear system can be described as a linear system with the co-ordinates transformations in differential geometry theory. Firstly, a non-linear theoretical model of the fixed speed wind turbine was built according to the physical characteristics. Then, the non-linear model was linearised globally with differential geometry transmission and a new linear model was prepared. Finally, a non-linear controller has been designed relying on the linear quadratic optimal algorithm of the new linear system.