Thermal-aware design and fault analysis of a DC/DC parallel resonant converter

Abstract

In this paper a 3-D electrothermal (ET) analysis of a DC–DC parallel resonant converter (PRC) for constant current (CC) application is presented. A full 3-D ET simulation approach is proposed at application level to provide a support for the design stage and to analyse possible fault conditions inside the active devices. Simulations and measurements have been performed on a 100W–2A prototype of a PRC-CC circuit with 80kHz nominal switching frequency.In particular, in the reported case study, the analysis has been focused on the full-bridge section of the circuit in order to prove the effect of the soft switching operation, introduced by the resonant technique, and consider the effect of possible fault conditions. To this purpose an unexpected short-circuit condition on a power MOSFET composing the H-bridge is considered, to evaluate the ET circuit behaviour and the time-to-failure of the power section. Considerations are carried out in terms of minimum requirements of protection circuits which must be fulfilled in order to avoid catastrophic system failure.A second power converter, rated for 1.5kW, has been then designed, based on the same circuital topology, and an ET simulation has been performed in order to carry out considerations on the effect of mismatches among the input bridge devices.