Neutral Voltage Modeling and Its Remediation for Five-Phase PMSMs under Single-Phase Short-Circuit Fault Tolerant Control

Field-oriented control (FOC) still serves as an advanced way to control ac motors for industrial applications, as such, this technique is being expanded to the postfault operation of five-phase permanent magnet synchronous motors ( 5Φ-PMSMs) under phase fault conditions. Previous articles have proved that the motor's neutral voltage (NV) oscillates over the dc-bus midpoint under a single-phase open-circuit fault (OCF), and NV remediation is needed for the successful fault-tolerant FOC. However, regarding the short-circuit faults (SCFs), neither the NV model nor its remediation is elaborated. The NV oscillates severely under SCFs, and it deserves an in-depth understanding for better making use of this faulty drive. To this end, this work establishes an NV model for a general 5Φ-PMSM under the single-phase SCFs, including interturn and ground SCFs, and an NV remedial rule is, therefore, provided to rectify the phase voltage modulation that forms the basis of an inverter-driven system. In addition, the presented rule requires little knowledge of the motor parameters, and it can also be very easy to implement. Finally, the experimental and simulation results confirm the validity of the presented NV model as well as its remedial method.