Comparative Reliability Analysis for Resonant Converter Operation under Component Ageing

This paper is concerned with reliability analysis in relation to optimal switching of resonant power converters, aimed at minimizing their power loss and operational temperature and thus reducing their lifetime degradation. In most cases, high performance resonant converter control requires a continuous adaptation of the power device switching instances depending on the power input source, load current, or parameter variation in passive components. If the resonant converter is switched before or after the resonant swing ends, more loss is added to the system, with effects in operating temperature rise and reliability deterioration. Even if the switching frequency is adjusted to keep the output voltage constant, it may influence the operational temperature. This article is quantifying this problem with a calculation of the lifetime implication for both cases of Zero Voltage Transition (ZVT) and Zero Current Transition (ZCT) buck converters. A broad range of parameter variation in passive components is considered due to ageing or aggravated stress. A thorough performance (lifetime / reliability) evaluation is achieved through a comparative analysis of results obtained for resonant converters with ideal operation, resonant converters with adjusted timing due to parameter variation, and hard-switched converters without any resonance. Conclusions are formulated in the end. The results reported in the paper should be of high interests to the power electronics community, given that resonant converters are used in a wide range of applications due to their ability to reduce power semiconductor losses.