Online Inductance Identification for PMSM Sensorless Control Immune to Position Error

The accuracy of position sensorless control depends largely on the permanent magnet synchronous motor (PMSM) inductance. Meanwhile, the PMSM inductance identification methods require the accurate rotor position. In position sensorless control, there is generally an angle deviation between the observed rotor position and the real rotor position, which will lead to error in PMSM parameters identification. In this paper, a relative rotation axis system and its high-frequency (HF) equivalent impedance model are proposed, in which the PMSM inductance identification and the rotor position error are decoupled. Therefore, by injecting the HF voltage signal, the PMSM inductance in position sensorless control can be accurately identified, which is immune to the rotor position error in position sensorless control. The experimental results show the effectiveness of the proposed PMSM inductance online identification method under different operation conditions.