Coupling Inductor Fault Detection and Estimation in Three-Phase Adjustable-Speed Drives With Direct Power Control-Based Active Front-End Rectifiers

Coupling inductors are the most commonly utilized filtering option in grid-connected direct power control (DPC)-based active front-end rectifiers integrated into three-phase adjustable-speed drives (ASDs). Inductor faults, e.g., common interturn short circuits, can drive the whole system to failure. In this paper, a novel strategy is proposed for the early detection of incipient faults in the coupling inductors of the aforementioned ASDs. The proposed method enables a fast identification of the defective phase. The strategy also provides an accurate estimation of the inductance value of the coupling inductors that improves the performance of the DPC method. Simulations and experimental tests demonstrate the validity of this detection and estimation strategy.