Speed estimation and fault detection for PMSM via quasi sliding modes

The paper presents a cascade control scheme for Permanent Magnet Synchronous Motors (PMSMs) based on a novel reduced order state observer which provides accurate speed tracking performance. The asymptotic vanishing of both the observation error and the speed tracking error is proven. The observer design allows a residual signal to be defined, able to detect faults using Park's vector currents. The performance of the proposed solution is evaluated by simulation using the model of a commercial PMSM drive.