Wind power is currently responsible for about 1:5% of the world’s electricity use. Because of this high interest in wind energy, it becomes more and more important to increase the efficiency of wind energy conversion systems (WECS) Such a system consists of a rotor to capture the energy in the wind, a gearbox configuration to speed up the rotational speed of the shaft and a generator to convert the mechanical energy into electrical energy. Blade pitch control is used to control the aerodynamic power captured from the wind. By pitching the rotor blades along their longitudinal axis, the aerodynamic efficiency of the rotor is changed. A disadvantage of using blade pitching below rated speed is that less energy is extracted from the wind, decreasing the efficiency of WECS. Power electronics widely used in the wind turbine industry to improve the performance of wind turbines. The biggest disadvantage of power electronics is reliability. Mechanical components show wear & tear and therefore any failures in these components can be predicted, maintenance can be scheduled before failure occurs. Unfortunately power electronics do not show signs of degrading, therefore failures cannot be predicted and these sudden failures are very expensive to repair.