Fixed-time disturbance observer based adaptive super-twisting sliding mode single-loop control of PMSM drives with variable gains

Aiming at improving the speed control performance of permanent magnet synchronous motors (PMSMs) considering lumped disturbances and overcurrent protection, a novel adaptive super-twisting sliding mode control (ASTSMC) strategy based on fixed-time disturbance observer (FTDO) is proposed in this paper. Firstly, to achieve fast speed tracking and current constraint, the equivalent model considering the q-axial current constraints is established. Secondly, a new adaptive super-twisting sliding mode single-loop controller with variable gains is proposed. The convergence speed is accelerated, and the transient performance is improved. Meanwhile, to improve the robustness against the external disturbances and parameter uncertainties, a fixed-time disturbance observer is firstly applied to estimate the lumped disturbances for the single-loop control of PMSM. Subsequently, based on the Lyapunov theory, the stability of the control system is analyzed, and the convergence time is calculated. Finally, the superiority and effectiveness of the proposed control scheme are verified through a series of comparative experiments.