Fault Phase Location for Interturn Short-Circuit Faults in Symmetrical Six-Phase PMSMs Based on Subspace Current Residual

Fault location can also be called fault isolation, which is an important task of fault diagnosis. This article proposes a fault location method for interturn short-circuit faults (ISCF) in symmetrical six-phase permanent magnet synchronous machines (PMSMs). In six-phase control systems, the six-phase states are usually mapped onto three subspaces by vector space decomposition (VSD) and the behaviors in each subspace are influenced by IS CF. In the fault location methods, the phase angle of short-circuit current is usually estimated by the inverse tangent function. In symmetrical six-phase PMSMs, there are three pairs of opposite phases. However, it is difficult to distinguish the opposite phases based on a high-harmonic signal due to the incomplete output range of inverse tangent function. In this article, a novel fault location method based on the x-axis current residual is proposed to overcome this problem. The proposed method has a high signal-to-noise ratio and does not need any additional sensors or searching coils. Simulation and experimental results show the effectiveness of the proposed method.