Position Offset Injection based Inductance and PM Flux Linkage Decoupled Estimation of PMSMs Considering Magnetic Saturation

Accurate parameters are crucial to achieve high quality control of permanent magnet synchronous machine (PMSM). This paper presents a multi-parameter estimation approach for permanent magnet flux linkage and inductances estimation of PMSM based on the position offset injection. At first, the estimation models for the permanent magnet flux linkage and inductances are derived from the machine model based on the positive and negative position offset injection. The estimation models are decoupled, in which the inductance and permanent magnet flux linkage estimations are independent from each other and not affected by the winding temperature rise. Moreover, the magnetic saturation is considered to enhance the accuracy of estimation, in which polynomials are employed to model the nonlinear variations of permanent magnet flux linkage and inductances with regard to stator currents. Under various operating conditions, the proposed estimation approach is verified on a test PMSM drive and compared with existing estimation methods.