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

Abstract

In this paper, 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 post-fault Two-Phase (2-ph) operation. By reconfiguring the wiring method, the fault-tolerant FL-DI topology is obtained, and the post-fault Three-Phase (3-ph) operation is realized. However, the current flow path changes and measurement vectors become unavailable in post-fault 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 (ZSC) suppression for the FI-DI fed OW-PMSM drive, which ensures better system performance in the post-fault 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.