The oscillation-instability mechanism of PMSM sensorless control caused by inductance mismatch and the stabilizing method

The model-based sensorless control of permanent magnetic synchronous motor (PMSM) relies on the parameter value. But in practice, the parameter mismatch is inevitable, which degrades the motor performance, even leads to the oscillation-instability. In this paper, by defining and analyzing the "current-interfering term", we theoretically investigate the oscillation-instability mechanism of PMSM sensorless control which is caused by inductance mismatch. Then, in order to avoid the instability problem, a stabilizing method based on current-differential-reconstruction-compensation (CDRC) is proposed. In this method, the "current-interfering term" is reconstructed using combined extended state observer (CSO), and is compensated in current reference value. The simulation results under different conditions demonstrate the correctness of the theoretical analysis and the effectiveness of the stabilizing method. (c) 2022 The Authors. Published by Elsevier Ltd. This is an open access article under theCCBYlicense (http://creativecommons.org/licenses/by/4.0/).