A framework for reliability evaluation of electric vehicle charging stations

The focus of this paper is to develop a framework to evaluate and analyze the reliability of the power electronic circuits in electric vehicle chargers, which are expected to be a major component of the utility load in the future. A general infrastructure of electric vehicle charging systems is described and different charging levels are discussed. To illustrate a numerical reliability analysis, two high power dc-dc topologies are selected and the mean time between failures of these converters that are widely used in electric vehicle charging stations are calculated and compared. The impact of each component in the power electronic circuit on overall system reliability is discussed and in particular the sensitivity to temperature, safety factor and capacitor type are studied. These factors have the highest impact on the system reliability. The framework developed in this paper has the potential to serve as a template for reliability evaluation and comparison of future on-board and off-board electric vehicle chargers.