Diagnostic Technique for Inter-turn Faults of PMSMs Based on Search Coils Using High-frequency Negative Sequence Components

This paper investigates inter-turn short circuit faults of the permanent magnet synchronous machine, and presents a fault diagnosis method based on search coils. A new embedded structure of search coils is designed, and the composition of search coil voltage signal is analyzed. Based on the analysis of voltage PWM harmonic variation, a high-frequency negative sequence component method for the diagnosis of inter-turn short circuit faults is proposed and the fault position can be located. In this method, the fault information is converted into the twice switching-frequency signal, which is not only beneficial to the design of the filter, but also can avoid the influence of speed variation. Compared with the traditional control method, this diagnosis strategy is more sensitive to inter-turn short circuit faults and less affected by the load. Finally, the effectiveness of the proposed fault diagnosis strategy is verified by an experimental platform.