A composite sliding mode control with the first-order differentiator and sliding mode observer for permanent magnet synchronous machine.

This paper proposes a composite sliding mode control (SMC) to optimize the tracking performance and the anti-disturbance performance of permanent magnet synchronous machine (PMSM) speed regulation systems. The differential term in the control law can magnify the measurement noise, resulting in more discontinuity. To filter out the high frequency noise and make the control law smoother, the first-order differentiator (FOD) is employed to estimate the speed error and its derivative. Since the feedforward compensation can improve the robustness of the system, a disturbance observer (DOB) based on the sliding mode observer (SMO) is designed to reinforce the dynamic performance under disturbance variation. Under the effect of the feedforward compensation, chattering can be further weakened by decreasing the switching gain appropriately. Finally, the effectiveness of the proposed methods is confirmed by various experimental results. • Compared to existing nonlinear controllers, the proposed methods are easy to understand and implement. Meanwhile, they possess strong anti-disturbance performance and tracking performance. • The amplification of measurement noise is effectively mitigated through the FOD, leading to a smoother control law. As a result, chattering is significantly attenuated. • The feedforward compensation via the SMO is adopted to improve the anti-disturbance performance, and accordingly, chattering is further reduced by decreasing the switching gain. [ABSTRACT FROM AUTHOR]