Fault-Tolerant Control of Common Electrical Faults and Sensor Faults in Sensorless PMSM Drives

Conventional sensorless control can hardly estimate the rotor position of faulty drives, which will cause the breakdown of the sensorless permanent-magnet synchronous motor (PMSM) drives in short time. In this article, a fault-tolerant (FT) control scheme is proposed for common electrical faults and sensor faults in the sensorless PMSM drive without using any auxiliary facilities. In the proposed FT control scheme, by simply updating the voltage inputs in the nonlinear flux observer (NFO), the rotor position is accurately estimated in open-phase fault (OPF) and open-switch fault (OSF). With the aid of the estimated rotor position, the current references are optimized by considering the tracking error and torque ripple for OSF and OPF. Besides, a Luenberger observer based on stator voltages model is established to estimate the faulty phase current in current sensor fault (CSF). The FT control for voltage sensor fault (VSF) is realized by compensating the measured DC-link voltage. Experimental verification is conducted to prove the validity of the proposed FT control scheme.