Use of independent pitch controllers to reduce load fluctuations caused by blade icing

A three blade independent pitch control strategy was used to reduce the impact of load fluctuations caused by wind turbine blade icing load. Firstly, a linear time-varying rotor model was set-up and, using a Coleman transformation, converted into a linear time invariant system, achieving decoupling of the system. Secondly, an independent pitch system PID controller was designed. Finally, the case of icing of a single blade was simulated using Bladed. The simulation analysis showed that the independent pitch control strategy is effective in reducing pitch moment and yaw moment fluctuations due to imbalanced blade icing.