Online cross-coupling and self incremental inductances determination of salient Permanent Magnet Synchronous Machines

The presence of saliency/anisotropy in a Permanent Magnet Synchronous Machine (PMSM) is essential to track the rotor position when using high frequency signal injection based sensorless control. At high frequency d-q incremental inductances become dominant over the d-q normal (chord) inductances. In addition when load is applied to the machine cross-coupling inductance arise since the saliency/anisotropy angle, which is synchronised with the rotor position at no and light load applications, is delayed from the actual rotor position. To estimate accurately the rotor position, cross-coupling and self incremental inductances have to be known at various operating points. In this paper online inductances determination technique based on the Goertzel algorithm is proposed to compensate for the position error. Analytical interpretation and simulation results are shown to validate the proposed technique.