Fault tolerant reconfiguration system for asymmetric multilevel converters using bi-directional power switches. http://dx.doi.org/10.1109/TIE.2008.2005680

Abstract

Asymmetric multilevel converters can optimise the number of levels by using H bridges scaled in power of three. The shortcoming of this topology is that the H bridges are not interchangeable and then, under certain faulty conditions, the converter cannot operate. A reconfiguration system based on bi-directional electronic valves has been designed for 3-phase cascaded H-bridge inverters. Once a fault is detected in any of the IGBTs of any H-bridge, the control is capable to reconfigure the hardware keeping the higher power bridges in operation. In this way, the faulty phase can continue working at the same voltage level by adjusting its gating signals. Some simulations and experiments with a 27-level inverter, to show the operation of the system under a faulty condition, are displayed.