Reduction of On-Load Torque Ripples in Permanent Magnet Synchronous Machines by Improved Skewing

Skewing is one of the most widely used methods to reduce the torque ripples. However, it was reported that the on-load torque ripple was not always reduced by the conventional skewing, in which the skewing angle is one period of torque ripple. This paper proposes the way of improving the skewing to reduce the torque ripple when the conventional skewing fails. It is found that by optimizing the skewing angle and current phase advance angle together, the improved skewing is able to meet the stringent torque ripple requirement over the whole load range.