Optimal Commutation Laws for Torque Control of Synchronous Motors

Synchronous Motors F. Aghili and M. Buehler J. M. Hollerbach Dept. Mechanical Engineering Dept. Computer Science McGill University University of Utah Montr eal, QC H3A 2A7, Canada Salt Lake City, UT 84112, USA ffarhad,[email protected] [email protected] Abstract This paper presents a new model for torque generation of synchronous motors and their control based on Fourier coe cients. Since multi-pole motors give rise to high frequency control signals, the dynamics of the current ampli er 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 ampli er dynamics are negligible, we present a commutation strategy which delivers ripplefree 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.