Application of nonlinear control to a HAWT

Wind energy is one of the most promising sources of renewable energy for the UK. Over the last two decades there has been rapid development of the technology, and in the UK several commercial wind farms are in operation with more under construction. The standard commercial design of wind turbine is a horizontal axis grid-connected up-wind machine with a rating of approximately 300 kW. The rotor usually has two or three blades, and in pitch regulated machines the pitch angle of either the full span of the blades or just the outer tips can be varied. The application of a nonlinear controller to a typical two-bladed machine with full-span pitch control is investigated in the present paper. It is known that this particular configuration of wind turbine presents a more demanding control problem than alternative configurations, and the benefits of a more sophisticated control system are therefore expected to be greater in the two-bladed case