An Adaptive Fault-Tolerant Control Without Fault Location of Open-Phase Fault for Dual Three-Phase PMSM Drive System

An adaptive fault-tolerant control (FTC) method without fault localization is proposed for the common open-phase faults (OPFs) in dual three-phase permanent magnet synchronous motor (DTP-PMSM) drive systems. The method eliminates the need for fault localization through fault diagnosis, thus reducing the risk of misdiagnosis. The operational state of the DTP-PMSM under OPF is analyzed and a uniform reference current with fault current angle is established in the dual dq coordinate system. After an OPF occurs, the unified current reference can be directly applied to the drive system without fault localization. The fault current angle is acquired by a phase-locked loop (PLL) and can still be well acquired even under light-load conditions. Compared with the existing PLL-based adaptive fault tolerance scheme, one PLL loop is reduced, which reduces the computational burden. The proposed adaptive FTC scheme does not require adjustment of the control framework, machine model, and transformation matrix before and after the OPF, and the switching between minimum copper loss (ML), maximum torque (MT) output, and healthy operation can be achieved by adjusting the amplitude coefficient of the reference current. The experimental results verify the effectiveness of the proposed FTC scheme.