Model Predictive-based Fault-tolerant Control for Modular Multilevel Converters Without Redundant Submodules

To improve the operation reliability of modular multilevel converters (MMCs), a fault-tolerant control method based on model predictive control (MPC) for MMC without redundant submodules (SMs) is proposed in this paper. It is sequenced by two steps. First, the AC current was conducted with optimal control. Second, multi-objective optimal control was carried out for circulating current and AC current. The calculation amount of the proposed method is 8 times. MMC can have good static and dynamic performance by the proposed control method not only under the normal condition but also under the faulty condition that the arm is asymmetric. The feasibility and advantages of the proposed method had been validated by the experimental results of a 5-level prototype.