Experimental Saliency Modeling of Synchronous Reluctance Motor with Four-Vector Injection

The saliency investigation of synchronous reluctance motor (SynRM) is essential for high-performance control, such as high-frequency-injection (HFI) based sensorless control and maximum torque per ampere (MTPA) control. However, the conventional methods focus on the primary saliency but neglect the secondary saliency that causes the parameter variation of the motor with electrical angles, which leads to degradation of the control performance. This paper proposes an experimental method for modeling the saliency of SynRM, which considers both primary and secondary saliency. The proposed method estimates the incremental inductance and then calculates the flux and apparent inductance based on the estimated incremental inductance. To address the rank-deficient issue of the conventional HFI method in estimating the incremental inductance, a four-vector HFI method is proposed to make the identification full-rank. Compared with the conventional modeling methods, the proposed method can model not only the variation of the inductance and flux parameters with currents but also the parameter variation with electrical angles. The effectiveness of the proposed method is validated on a 3-kW SynRM drive.