A comparison of redundant inverter topologies to improve voltage source inverter reliability

For applications sensitive to reliability, typical voltage-source inverters (VSIs) cannot always meet the reliability requirements. In these cases, some method of redundancy is used to improve system reliability. This paper compares the reliability of two redundant VSI circuit topologies to a typical VSI circuit. The redundant circuits function normally after the failure (open or short) of any single component, including the controller, current and voltage sensors, capacitors, insulated gate bipolar transistors, and power diodes. The parts count method of reliability comparison that is described in MIL-HDBK-217F is used to compare the reliability functions for the three circuit topologies.