Phase Current Reconstruction for Y-Type Converter Fed Switched Reluctance Motors Drive With Fault-Tolerant Ability

Fault tolerance and accurate current detection are crucial for the long-term stable operation of switched reluctance motor (SRM) drives, especially under extreme working conditions. In this paper, a novel Y-type converter topology with inherent fault tolerance ability is proposed first. Compared to conventional half-bridge converters, the Y-type converter doubles the phase current flow paths without additional power switches. In this case, switch open-circuit faults can be effectively tolerated by properly adjusting the current flow path, enhancing system reliability. On this basis, a novel current reconstruction strategy using only a single current sensor is also put forward to further ensure accurate current detection ability. In the two-phase current overlap conduction region, the composition of the sampled current varies with the phase current flow path. By sampling twice before and after the current path modification, the phase current can be preciously reconstructed through real-time calculations. Unlike traditional methods that rely on pulse injection, the proposed strategy eliminates the associated voltage penalty and improves accuracy and performance. Finally, experimental validation is conducted using a 750-W 12/8 SRM to confirm the fault tolerance and current reconstruction ability of the proposed scheme.