A generalized model predictive fault-tolerant control strategy for hybrid multilevel converter under arbitrary open-circuit failures

This paper investigates the fault-tolerant (FT) operation of the T-type converter using a cascaded H-bridge (T 2 C-HB) topology under open-circuit failures (OCF) occurring in any IGBT switch. The high number of switches in the hybrid multilevel converter (HMC) increases the possibility of switch faults. However, existing FT control methods for HMC primarily focus on local faults, making them ineffective in addressing global faults and thereby limiting overall system reliability. To achieve global FT control, this paper proposes an FT strategy based on model predictive control (FT-MPC), which consists of two stages. In the first stage, the optimal redundant voltage vector position is determined by employing an optimal current tracking strategy. In the second stage, an initialization function is introduced to integrate various types of OCF into a unified framework. By employing weighting factors within the selected redundant voltage vectors, the optimal switching states are determined. The proposed method effectively handles various types of OCF and is applicable to any HMC incorporating cascaded H-bridge modules. Simulation and experimental results validate the feasibility and effectiveness of the proposed method.