Stator Flux Sliding Mode Observer of Permanent Magnet Synchronous Motor Based on Effective Flux

In order to improve the stator flux observation performance of permanent magnet synchronous motor (PMSM) with DIRECT Torque Control (DTC), a stator flux sliding mode observer is proposed based on the concept of effective flux. The stator current and effective flux in the stator stationary coordinate system are taken as state variables to construct the corresponding sliding mode observer. The stator flux is calculated according to the observed effective flux. Experimental results show that the proposed observer can obtain more accurate stator flux observations than the open-loop observer. The proposed observer has strong robust suppression ability to the variation of motor inductance.