An Improved Current Prediction Model for PMSM Drives Under Single Open-Phase Fault Considering Floating Motor Neutral

The diagnosis and fault-tolerant control of open-phase faults in permanent magnet synchronous motor (PMSM) drive significantly rely on models describing post-fault behaviors of current and voltage. This paper aims to propose an improved current prediction model that can accurately estimate the post-fault current dynamics under the single open-phase fault. Firstly, in each switching state, the post-fault phase voltages are derived by considering the floating neutral voltage incurred by the back electromagnetic force (back-EMF). Furthermore, by incorporating the derived phase voltages as the activation sources in each switching cycle, the post-fault current prediction model is established. Moreover, the changes of inductances under the open-phase fault are taken into account by establishing the model in the independent phase model. Finally, experimental results validate the derived post-fault phase voltages and the post-fault current prediction model.