Using the drive train of an gearless wind-energy-converter for active damping of oscillations in rotor blades

By the increasing nominal power of wind energy converters, an optimized management, a higher level of efficiency and reduced costs are needed. In search of suitable generator systems and concepts for wind turbines in the MW class, among others, the permanent-magnet synchronous machine as a generator moves to the focus of current discussions. The Rotor and its blades are able to oscillate due to various dynamic loads a wind energy converter is exposed. In wind energy converters in the Multi MW-class the natural frequencies of the blades have the same range as the naturals of the drive train. Thus blades are no longer isolated from the generator and inverter system to consider in terms of their dynamics, but must be embedded in the overall structure of the energy conversion train. This paper deals with the different types of rotor blade oscillations and its influence to the drive train as well as the possibility to influence the oscillations develop and use a new control strategy for the drive train.