Sensorless Vector Control of PM Synchronous Motors during Single-Phase Open Circuit Faulted Conditions

This paper deals with the study and development of new control solutions of Permanent Magnet Synchronous Motor drives specifically aimed to operate under sensorless vector control even during fault conditions. The phase unbalance produced by an open-phase fault leads to the failure of several sensorless estimation algorithms based on either machine models or high frequency signal injection. Exploiting a recently proposed machine model for three-phase faulted permanent magnet synchronous motor drives, the practical implementation is performed of sensorless vector controls for such drives under asymmetric conditions due to a single-phase open circuit fault. The effects of the magnetic/geometrical asymmetries during the fault are studied and the techniques able to mitigate such effects on the rotor position information are provided. The rotor position estimation is achieved in a wide operating range during the fault as it is confirmed by experimental tests.