Fast detection of open-switch fault in cascaded H-bridge multilevel converter

Cascaded H-bridge converter has been utilized recently in diffierent high-power applications due to its modular and simple structure. In order to have a balanced operation after a fault occurrence in this converter, it is necessary to detect the switch fault and its location. In this paper, a fast power-switch fault detection method is presented to identify a fault and its location. Only one voltage measurement per phase is required by this method, and the fault detection is faster compared to the existing methods. Moreover, it is suitable for implementation on an FPGA device due to the use of simple math, relational, and state machine blocks. The proposed method is veried by computer simulations and FPGA-based experimental tests.