A new approach to open-circuit fault diagnosis of MMC sub-module

Abstract

This paper is concerned with the open-circuit fault diagnosis of MMC sub-module. To estimate the arm current accurately in normal and fault cases, a sliding mode observer is designed based on Lyapunov theory. The residual between the estimation and measurement of the arm current will increase rapidly in fault cases, which can facilitate not only the open-circuit fault detection of the arm but also the identification of the fault type. Based on the open-circuit fault analysis of MMC sub-module, the fault feature is defined and calculated for the fault location of sub-module, which can remarkably promote the efficiency of fault diagnosis. To test the performance of the proposed approach, some simulation experiments are carried out and can confirm the effectiveness of the proposed approach for the open-circuit fault diagnosis of MMC sub-module.