Sensitivity analysis of reliability performance of multi-level converters

In recent years, several multilevel converters have been developed for high power applications. The basic multilevel converter types are: diode clamped, capacitor clamped and cascade. From these basic configurations, numerous configurations have been developed to achieve different performance objectives such as increasing efficiency, reducing number of diodes or switches and increasing system reliability. The wide applications of these converters motivates the development of reliability methods to evaluate the performance of such devices. There are some work were done on estimating power electronic converters reliability indices. However, these indices do not identify the most critical components or parameters for system reliability. This paper defines an index, Performance Degradation Probability (PDP) and evaluates its sensitivity with respect to components parameters such as their availabilities, failure rates and repair times. The method is demonstrated on a generalized five-level converter.