Competitive study on reliability of difference voltage levels of NPC multilevel inverters

The issue of reliability in power electronic converters (PECs) has received comparatively less attention by researchers. Among PECs, the multilevel inverter is a favourite choice of industry in the area of medium-voltage and high-power uses. To study the reliability of PECs, first, the failure rates of elements such as diodes, capacitors, and switches are introduced based on a relevant standard. Then, the reliability indices of two converters, 3-level and 5-level neutral point clamped, are calculated and compared. The results of the reliability study indicate an appropriate converter for sensitive application in industry.