Fault analysis on conventional parallel inverter systems

Field experiences have demonstrated that semiconductor devices are vulnerable to failures. This paper investigates the fault analysis regarding conventional parallel inverter systems. The stage analysis for the parallel inverter system in case of IGBT short-circuit is analyzed firstly. Then, the current impacting on the inverter system due to the IGBT short-circuit failure of one inverter is discussed. The corresponding peak fault current and fault isolation time are explored. The mathematical expressions for these two issues are derived, which is helpful for the redundancy design of the system. Finally, the experimental results are provided to verify the theoretical analysis.