Self-Adaptive Fault-Tolerant Control of Three-Phase Series-End Winding Motor Drive

This article proposes a simplified fault-tolerant control (FTC) method for three-phase series-end winding motor drive, which has four bridges to achieve high voltage utilization and increased degrees of control freedom. Seven fault types are analyzed and the corresponding voltage/current derating is calculated. The proposed self-adaptive fault-tolerant strategy applied for the first fault category acts in both healthy and faulty conditions, which avoids the risk of delay and error caused by fault diagnosis, and achieves smooth fault-tolerant transition. Compared with existing FTC methods for the same structure, the proposed control strategy can achieve obviously better voltage utilization. In addition, to further exploit the maximum speed potential in the linear modulation zone, the improved common-mode voltage injection is adopted. The performance of the proposed fault-tolerant method is validated experimentally in an open-end three-phase induction machine system with the open-circuit fault.