Advanced control scheme for an IPM synchronous generator-based gearless variable speed wind turbine

This paper proposes a direct control strategy for an interior permanent magnet (IPM) synchronous generator based variable speed wind turbine. In this scheme, the requirement of the continuous rotor position is eliminated as all the calculations are done in the stator reference frame. This scheme possesses advantages such as lesser parameter dependence and reduced number of controllers compared with traditional indirect vector control scheme. The direct control scheme is simpler and can eliminate some of the drawbacks of traditional indirect vector control scheme. The proposed control scheme is implemented in Matlab/SimPowerSystems and results show that the controller can operate under constant and varying wind speeds. Finally, a sensorless speed estimator is implemented which enables the wind turbine to operate without mechanical speed sensor. Simulation and experimental results for the sensorless speed estimator are presented.