Compatible Phase Current Reconstruction Scheme for Fault-Tolerant Five-Leg Dual-Inverter Fed Open-Winding Permanent Magnet Synchronous Motor

In this article, a novel phase current reconstruction strategy for a five-leg dual-inverter (FL-DI) fed open-winding permanent magnet synchronous motor (OW-PMSM) drive is put forward. Benefiting from the doubling of the power legs, the OW-PMSM drive is endowed with outstanding fault-tolerant ability. When an open-circuit fault occurs, the OW-PMSM automatically turns to the postfault two-phase operation. By reconfiguring the wiring method, the fault-tolerant FL-DI topology is obtained, and the postfault three-phase operation is realized. However, the current flow path changes and measurement vectors become unavailable in postfault operation processes, making the existing current reconstruction schemes unusable. To prevent the system collapse caused by the current reconstruction failure, a novel current reconstruction strategy is proposed, which can be applied in the case of the open-circuit fault in any leg. In addition, the proposed current reconstruction strategy is compatible with the specific zero-sequence current suppression for the FI-DI fed OW-PMSM drive, which ensures better system performance in the postfault operation. The reconstructed current is of high accuracy, where the relative reconstruction error is 7.8% at low load and 5.3% at heavy load. Finally, experimental results are presented to verify the feasibility and effectiveness of the proposed strategy.