Active Disturbance Rejection Repetitive Control for Current Harmonic Suppression of PMSM

Current harmonics will deteriorate the performance of permanent magnet synchronous motor drives, and active disturbance rejection control (ADRC) is a promising method to reduce the harmonics. However, determined by the observation and compensation level of extended state observer (ESO), the harmonic suppression ability of the traditional ADRC is limited. To significantly decrease low-frequency current harmonics, this article proposes a novel active disturbance rejection repetitive control scheme used for current loops, in which two improvements for the ESO are presented. One is the introduction of a low-pass filter (LPF) instead of the conventional integrator, and that can enhance the disturbance observation capability. Based on this new LPF-ESO, the other is the increase of a repetitive controller in parallel with the disturbance loop, which can further estimate the periodic disturbances and thus improve the compensation performance at specific periodic frequencies. The parameter design, stability, antidisturbance ability, tracking performance and robustness of the proposed ADRC current loop are analyzed. Compared with the traditional ADRC, the proposed scheme can obviously reduce the current harmonics, moreover, fast dynamic response and strong robustness can be achieved. The simulation and experimental results about a 1.1  KW PMSM are provided to verify the effectiveness of the proposed scheme.