Impact of individual pitch control on pitch actuators in megawatt wind turbines

Abstract

Individual pitch control is seen as a promising control technique for load reduction of the rotor blades in megawatt wind turbines. As the rotor blades are getting bigger and bigger, the asymmetric loads due to wind speed variations across the rotor area are increasing, too. Modern wind turbines include individual pitch actuators for every blade and the control effort is also reasonable. This is why a lot of research has been done on individual blade pitch control strategies and their impact on load reduction and further stress of the mechanical components, such as pitch bearings. The present work shows that individual pitch control is able to reduce mechanical fatigue loads, however, it affects the dynamic loads of the pitch motors and might lead to an increased overall stress of their power electronic converters.