Robust current control for PMSMs using sliding mode control with uncertainties estimation

In this paper, a simple and novel sliding mode controller (SMC) with uncertainties estimation is proposed for robust current control in a permanent magnet synchronous motor (PMSM). Based on the Lyapunov stability theorem, estimation laws are derived to estimate uncertainties of a PMSM caused by parametric variations or unmodeled dynamics and the system robustness, as well as stability is guaranteed. On-line estimated uncertainties can be used to eliminate the effect caused by the real uncertainties. Superior control performance can be obtained and a limitation in conventional SMC which is to know the upper bounds of the system uncertainties is not necessary. The proposed control method is very simple and can be effectively implemented. Simulation results are presented to demonstrate the effectiveness of the proposed control algorithm.