High performance control of the permanent magnet synchronous motor using self-tuning resonant controllers

The permanent-magnet synchronous motors (PMSM) have been widely used in high-performance variable speed drives. However, any non-ideal conditions, such as nonsinusoidal distributed rotor permanent magnet flux or the cogging effects, may bring on ripples in the output torque. In this paper, we propose to suppress the torque ripple of the PMSM in the stationary reference frame by using self-tuning multiple-frequency resonant controllers. This kind of controller is usually used to track the non-sinusoidal command and/or reject some kind of higher-order harmonic disturbances in AC current control system. We first present how to design the robust self-tuning resonant controller using pole assignment technique, in which the influence of unit time-delay is compensated. After that, the optimal excitation current waveforms are designed to suppress the torque ripples caused by the back-EMF harmonics. The torque ripples can be completely eliminated up to an arbitrary order. By using the self-tuning multiple-frequency resonant controllers, the regulated currents can perfectly track the optimal excitation currents, and the undesired torque ripple is therefore efficiently suppressed. The experimental results confirm the validity and effectiveness of the proposed method