An Integration Redundancy Control Strategy for Enhancing the Fault‐Tolerant Performance of Modular Multilevel Converters

Submodule (SM) failure is one of the key factors leading to instability in modular multilevel converter (MMC) systems. To address this challenge and enhance system reliability, redundant configurations have become the core solution. However, existing redundancy strategies cannot simultaneously balance the transient repair speed and steady‐state output accuracy. Hence, a novel fusion redundant control scheme that combines cold‐standby and hot‐standby redundancy strategies is proposed to overcome the challenge of optimizing both transient repair speed and steady‐state output accuracy. First, an MMC structure is proposed, which is equipped with both cold‐standby SMs and hot‐standby SMs and realizes the sharing of cold standby SMs. Then, the casting and switching strategies of the SMs are designed based on this structure. Finally, a bridge arm reference voltage update module is designed to avoid the voltage offset caused by the coordination of the cold‐standby module and the hot standby module. Simulation and experimental results confirm that the proposed method effectively addresses both transient and steady‐state performance issues, facilitates rapid repairs, and ensures precise and reliable operation of the MMC system after a fault event.