Hydraulically actuated horizontal axis wind turbine pitch control by model free adaptive controller

In the present work a model free fuzzy feedforward PID controller has been developed for pitch control application of the horizontal axis wind turbine through electrohydraulic pitch actuation system. The controller has been designed to achieve maximum power tracking and protect from high wind gusts even with fault in the actuating system. Electrohydraulic pitch actuating system has high power to weigh ratio, self-lubricating property, good controllability etc. as its merit of application. Nonlinear mathematical model of small horizontal axis wind turbine along with proportional valve controlled electrohydraulic pitch actuating system has been developed. The BEM theory has been used to estimate aerodynamic load on the turbine blade and pitch for maximum power capture by the turbine with the variation of the wind speed. The present model has been validated with experimental results. The performance of the proposed fuzzy feedforward PID controller has been investigated with various test signals as well as predicted pitch demand from wind data for maximum power tracking and to save from high wind gusts. The performance index of proposed fuzzy feedforward PID controller has been found as 0.08606, 0.08849 and 0.09809 with normal leakage, high leakage and very high leakage respectively.