Adaptive Position Estimation Error Suppression Method Based on Limit Cycle Oscillator for Sensorless PMSM Drives

In the flux model–based position sensorless permanent magnet synchronous motor (PMSM) drive system, cross-saturation effect, parameter mismatch, and other factors cause errors in the flux and position estimation. In this article, a novel adaptive position estimation error suppression method based on a limit cycle oscillator (LCO) is proposed for PMSM drives. Based on the estimation error analysis of the hybrid flux model–based sensorless control strategy, by tracking and minimizing the back electromotive force error in the estimated frame, the stator flux rotation trajectory can be corrected adaptively. The LCO-based adaptive algorithm offers a novel approach for the suppression of position estimation offset error and can further suppress the harmonic error by correcting the vector angle of active flux due to its self-excited oscillation function. Furthermore, the stability, the parameter sensitivity, and the parameter tuning are investigated theoretically in detail. The effectiveness of the proposed method is verified by experiments on a 2.2-kW PMSM drive platform.