Phase Current Magnitude Adaptive Fault Tolerant Control of Dual Three-Phase Interior PMSMs Under Open-Phase Fault

For dual three-phase permanent magnet synchronous machines (DT-PMSMs) under open-phase fault (OPF), the remaining healthy phase currents are optimized to achieve fault tolerant control (FTC), and the optimal currents are often unbalanced to ensure control performance. In existing FTCs, once optimal currents are designed, the phase with the largest magnitude is fixed and remains the largest under most conditions. Hence, this phase is always under high loss and thermal stress, which is prone to fault and limits the maximum torque capability. This article presents a phase current magnitude (PCM) adaptive FTC for DT-PMSMs, in which PCM can be adaptively controlled to avoid overheating of phase winding and improve maximum torque capability. Moreover, maximum torque per loss (MTPL) strategy is developed to minimize the total copper loss for a given torque. The FTC with adaptive PCM model is first derived, based on which the MTPL FTC is formulated and computation-efficient optimal solution is derived. Moreover, the control rule is designed to adaptively adjust the PCM, which can ensure the machine to safely delivers a large torque and improves torque capability. The proposed approach is validated on a test machine under various operating conditions.