Optimal commutation laws for torque control of synchronous motors

This paper presents a new model for torque generation of synchronous motors and their control based on Fourier coefficients. Since multi-pole motors give rise to high frequency control signals, the dynamics of the current amplifier are no longer negligible. For this case, we present a new commutation strategy which minimizes the torque ripple and the velocity induced change in the torque transfer function. When the amplifier dynamics are negligible, we present a commutation strategy which delivers ripple-free torque and simultaneously minimizes copper losses. The performance of both commutation laws is validated via simulations based on experimental data from a synchronous motor. The approach can be adapted for general brushless motors