Multi-degree open-phase fault diagnosis and fault-tolerant control of dual three-phase PMSM drives

Abstract

Open-phase faults (OPFs) seriously degrade the reliability of dual three-phase permanent magnet synchronous motor (DTP-PMSM) drives. Existing methods mainly diagnose first faults from healthy operation, while secondary OPFs during fault-tolerant control (FTC) are less addressed. This paper proposes a unified diagnosis and FTC scheme for multi-degree OPFs. Based on vector space decomposition, harmonic-subspace current variation is used for fault detection, and spatial current-vector relationships locate the faulty phase or winding set. The scheme covers single-phase, two-phase, three-phase winding-set, and sequential OPFs during FTC. Experiments verify accurate localization and stable post-fault operation.