Sliding mode control based on singular perturbation theory for position tracking of permanent magnet stepper motors

In this paper, we propose sliding mode control (SMC) based on singular perturbation theory (SPT) for position tracking of permanent magnet stepper motors (PMSMs). Separate time scale is a characteristic of the singular perturbation method. Therefore, singular perturbation theory can be applied to the position tracking control of PMSMs because the dynamics of PMSMs is separated into slow and fast dynamics. The proposed method consists of torque modulation, commutation scheme, and SMC. Torque modulation was developed to generate the desire currents. For position control, the SMC was proposed only position feedback without any other observer. The simulation results validate the performance of the proposed method.