Reliability Analysis Considering the PFC Function and Redundancy Effect of the Vienna Converter

Abstract

This paper analyzes the impact of power factor correction (PFC) on the failure rate of a Vienna converter through reliability analysis under conditions where AC-to-DC conversion is possible but the PFC function is not functioning due to a partial failure in the Vienna converter. While reliability analysis for partial failures typically utilizes a Markov model, this paper applies the Fault-tree analysis (FTA) technique to analyze the impact of specific functions on the failure rate. Compared to determining PFC failures as the Vienna converter’s entire failures, reliability is improved by approximately 1.78 times. Furthermore, since Vienna converters are often used in modular configurations, the impact of redundancy on reliability in parallel configurations is analyzed. As redundancy increases from 0% to 50% and 200%, the mean time between failures (MTBF) improves from 1.1 to 2.9 years and 6.5 years, respectively, demonstrating that parallel configurations and module rating margins significantly improve system reliability. The Cost model analysis (CMA) results confirmed that while overall costs increase with increasing redundancy, the incremental cost of Vienna converter per 1% redundancy gradually decreases. This demonstrates that a high-redundancy design can be an effective strategy regarding reliability and cost.