A modified approach for efficient cogging torque suppression in a flux switching permanent magnet generator used in micro-scale wind turbines

Abstract

In recent years, Flux Switching Permanent Magnet (FSPM) machines have attracted notable attention in direct drive, low speed, and high torque density applications such as wind turbines. However, their relatively high cogging torque has been identified as a significant challenge for such applications primarily because of its effects on both starting and running performance of the wind turbines. The authors, therefore, aim to present a modified approach that can improve the cogging torque issue and eliminate the weaknesses of the previously introduced designs. To reach this goal, first, an operating point is chosen for the studied machine regarding the available small-scale turbines in the market. Then, the potential benefits of combining different cogging torque reduction schemes are investigated thorough the proposed method. This is intended to be done on the rotor teeth without imposing any complications or extra costs. The results show that a simultaneous improvement in the cogging torque and the energy conversion capability of the machine could be achieved through this cost-effective approach. To end with, the sensitivity of the best cases to the expected manufacturing tolerances is investigated. All analyses are performed via two-dimensional finite-element (2D-FE) models, the accuracy of which has been pre-certified through experimental measurement.