An Open-Circuit Fault Detection Method Using Wavelet Transform for Cascaded H-Bridge Multilevel Inverter

Fault detection in multilevel converters is an important feature particularly in applications such as electric vehicles where detecting in different situations is very important. However, in electric vehicles, changes in speed and torque will affect the input voltage and current. Therefore it is important to identify the faulty semiconductor in different situations to isolate it from the system. In this paper, a seven-level cascaded H-bridge motor drive is chosen on which the proposed fault detection technique is applied. The proposed technique uses the current signature to detect the faulty module. The feasibility of the proposed method is verified in a seven-level inverter in simulation when motor load is not constant.