Modified ADRC Based on Quasi-Resonant Fixed-Time-Convergent Extended State Observer for PMSM Current Regulation

Robust and smooth current control is very important for permanent magnet synchronous motor (PMSM) drives. However, aperiodic and periodic disturbances generally exist in PMSM system, which reduces the system stability and leads to current harmonics. Conventional active disturbance rejection control (CADRC) can only converge in an infinite domain and cannot effectively deal with current harmonics. Thus, a modified active disturbance rejection control (MADRC) with a quasi-resonant fixed-time-convergent extended state observer (QRFESO) is proposed for PMSM current regulation in this paper. Firstly, the QRFESO is designed based on quasi-resonant technique and fixed-time control theory to suppress the current disturbances. Compared with conventional extended state observer (CESO) of CADRC, the QRFESO has faster convergence speed and stronger robustness, and can effectively estimate current harmonics. Then, the fixed-time convergence property of the QRFESO is proofed by constructing a homogeneous Lyapunov function, and the performance analysis of the proposed method is given utilizing the frequency-sweep scheme. Finally, the feasibility and effectiveness of the proposed method are verified on a PMSM experimental platform.