A Fast Open-Circuit Fault Diagnosis Scheme for Modular Multilevel Converters with Model Predictive Control

Fault diagnosis is a crucial way to increase the reliability of modular multilevel converters (MMCs) which consist of a large number of submodules (SMs). This paper proposes a fast fault detection and isolation (FDI) method to identify single open-circuit faults for MMCs with model predictive control (MPC). The proposed FDI method is simply implemented by comparing the applied arm voltage obtained in the former control cycle and the estimated arm voltage calculated by the load and circulating current models. No additional transducer or measurement is required. Experimental results show that an open-circuit fault in the MMC can be accurately detected and isolated in a very short time.