Discrete-Time Repetitive Control-Based ADRC for Current Loop Disturbances Suppression of PMSM Drives

The current loop is the key to realizing high-precision permanent magnet synchronous motor (PMSM) drives. However, the performance of the current loop is deteriorated by the dc and ac disturbances. To deal with the problem, this article proposes a discrete-time repetitive control-based active disturbance rejection control (ADRC) for the current loop. The discrete-time repetitive controller is embedded in the control law of the ADRC and operates in parallel with the discrete-time extended state observer (DESO), which is the core of the ADRC. The repetitive controller is designed to compensate for the ac disturbance, while the DESO is designed to suppress the dc disturbance. The stability and antidisturbance capability of the studied scheme are analyzed theoretically in the discrete-time domain, which can guide the tuning of control parameters. Compared with the existing ADRC-based PMSM control schemes, the studied scheme can suppress the dc and ac disturbances simultaneously, thereby improving dynamic- and steady-state performance of the current loop. Finally, the effectiveness of the studied scheme is validated on a 4.4-kW PMSM drive platform.