An enhanced equivalent input disturbance approach to current control of PMSM with periodic and aperiodic disturbances.

The current-loop control of a permanent magnet synchronous motor (PMSM) system suffers from periodic and aperiodic disturbances, which result in current ripples and degrade control performance. This paper presents an enhanced equivalent-input-disturbance (EID) approach to reject periodic and aperiodic disturbances in the current loop of a PMSM. Two additional quasi-resonant compensators (QRCs) are integrated into a conventional EID estimator with a low-pass filter (LPF) to handle the disturbances. The configuration of an enhanced EID (EEID)-based control system for PMSM current loop is explained. An analysis in the frequency domain shows the mechanism of the presented method for rejecting periodic and aperiodic disturbances simultaneously. It reveals that the sensitivity reduction of the system for aperiodic disturbances is mainly determined by the bandwidth of the LPF and that for periodic disturbances is determined by the parameters of the QRCs. The stability of the system is analyzed using the Nyquist stability criterion. The design algorithm for system parameters is provided. Compared to the conventional EID approach, the proposed method provides an additional degree of freedom to deal with periodic disturbances. The design of the QRCs is independent of each other, which makes the proposed method flexible and easy to implement. The effectiveness and the superiority of the EEID approach are validated by simulation results of a PMSM system. [ABSTRACT FROM AUTHOR]