Investigation of two Torque Ripple Minimization Techniques of a HESG in a Wind Conversion

Abstract

A new topology for a Wind Conversion System (WCS) based on a Hybrid Excitation Synchronous Generator (HESG) is considered in this paper. This generator is characterized by a robust structure where no brushes or slip rings are required. Moreover, the flux is created by both permanent magnets and DC excitation coils. Thus, it may be adjusted easily, which makes the architecture suitable for a WCS. Unfortunately, the electromagnetic torque ripple is relatively important in this kind of generator. The rippling may propagate to the drive train of the wind turbine and thereby may have a detrimental effect on the WCS lifetime through mechanical vibrations. This work investigates two techniques for reducing the electromagnetic torque ripple. The approaches include the circuit topology and the control strategy. The two methods have been tested by simulation and then, a set of specifications regarding the acceptable inductances and flux harmonics' amplitude is provided.