Torque ripple suppression of permanent magnet synchronous motors considering total loss reduction

This paper presents a current optimization methodology which achieves torque ripple suppression with the total loss (i.e. copper and iron losses) reduction in permanent magnet synchronous motors (PMSMs). The optimal current command can be easily obtained from a torque equation expressed with an instantaneous current vector and is consequently non-sinusoidal. In general, the current distortion increases not only copper but also iron losses. To minimize the total loss, parameters which have a dependence of the flux linkages is taken into account in the proposed technique. As a result the optimal current command can achieve the smooth torque production with the minimum total loss under conditions in which the iron loss is non-negligible. The effectiveness of the current optimization strategy is verified by performing some simulations and experiments in an interior type PMSM.