Leg-Shared Fault-Tolerant Predictive Control of Four-Quadrant Motor Drive Systems

Back-to-back power converters are widely applied in advanced motor drive systems, e.g. permanent magnet synchronous motor (PMSM) drive systems, due to their advantages such as four-quadrant operation capability and good grid-tied power quality. However, semiconductor switches in the converter are fragile, which leads to high potential of operation failure. Therefore, fault-tolerant control techniques become increasingly important for advanced motor drive systems. This work presents a leg-shared fault-tolerant predictive control strategy for a two-level back-to-back power converter fed PMSM drive systems. Different from the existing DC-link shared strategies, the proposed strategy takes the whole converter as a centralized target without linking the faulty leg to the neutral point of DC-link capacitors, avoiding voltage unbalance of the capacitors. Additionally, to reduce calculation burden caused by the centralized prediction control, we divide calculations into two groups based on the shared leg's switching state. Simulation results confirm that the proposed strategy achieves effective fault-tolerant control without DC-link voltage unbalance.