Absolute Inductance Estimation of PMSM Considering High-Frequency Resistance

In this article, a new high-frequency PMSM model is derived in order to obtain accurate absolute inductance and inductance saturation profile. Compared to traditional PMSM models, the proposed high-frequency model includes the components of high-frequency resistance and inductance derivative relative to current. Through this model, the difference between differential and absolute inductances is discussed in detail and the impact of high-frequency resistance on the inductance estimation is analyzed. In the next step, another method is proposed to decouple and eliminate the effect of high-frequency resistance from the composite inductance. It is shown that this approach yields highly precise absolute inductance measurement and remarkably reduces the effect of inductance derivative relative to current. These findings help to evaluate the saturation more accurately which is essential for robust observer and controller design. Finally, the effectiveness of proposed scheme is experimentally verified using SPMSM and IPMSM.