An Integral Sliding Mode Back-EMF Observer for Position-Sensorless Permanent Magnet Synchronous Motor Drives

The continuous reaching law is generally applied to reduce the chattering in sliding mode observer for position-sensorless permanent magnet synchronous motor (PMSM) drives. However, the robustness is accordingly reduced, and there exists output error problem. To address this problem, this paper proposed an integral sliding mode observer (ISMO). Compared with the conventional observer, it can compensate the estimated back-electromotive force (EMF) error by adding the presented integral term into continuous reaching law. The experimental results show the validity of the proposed ISMO.