A Diagnostic Method for Inter-Turn Short Circuit Faults Based on High Frequency Park Vectors

Stator winding inter-turn short-circuit fault (ITSCF) is one of the most severe faults of permanent magnet (PM) machines, which needs to be detected quickly and reliably. This paper analyzes the Park vector under healthy and faulty conditions and point out that the fault signature can be strengthen when high frequency (HF) conditions. In order to extract the optimal fault characteristic signal, a three-phase symmetrical HF voltage is injected into the drives. Then, the HF Park vector is calculated by extracting three-phase HF current component in real time. Compared to the current Park vector at low frequencies, the fault characteristics exhibited by the current vector at HF are more significantly. The effectiveness and robustness of the proposed detection method is verified under various load and speed conditions via a triple 3-phase PM machine drives.