Abstract
The second-order sliding mode control has strong robustness. Its application has greatly improved the anti-jamming ability of permanent magnet synchronous motor(PMSM) speed control systems. However, the influence of noise is unavoidable due to the introduction of a differentiator in the second-order sliding mode control, and the steady-state performance of the system is poor due to the absence of a q-axis current loop. This paper proposes a second-order sliding mode control method based on singular perturbation, which decouples the PMSM speed control system into two subsystems, the slow subsystem, including the speed variable, adopts second-order sliding mode control, and the fast subsystem, including the current variable of q-axis, adopts linear control. The design of a sliding surface for the slow subsystem avoids the application of the differentiator, which reduces the chattering better. Besides this, the steady-state performance of the system is improved due to the introduction of the feedback current of the q-axis. Experimental results show that the proposed method has strong robustness and can achieve high-precision control.