Thermal-electrical averaging model of resonant converters based on extended describing function method

Owing to limited computational resources and the very large difference between electrical and thermal time constants, simulation for resonantly operated DC-DC converters using physical or ideal switching model is very time-consuming or impossible. In this contribution, a novel thermal-electrical averaging model of resonantly operated DC-DC converters is proposed to reduce the computational burden and time consumption. The thermal-electrical model is based on extended describing function method. All required parameters for the thermal model can be obtained from the datasheets or on the website. The thermal-electrical models are applied in series-parallel resonant converters with LC-type and C-type output filters as examples, and verified by comparison with two standard simulation tools. The thermal-electrical modelling procedure proposed in this contribution can of course also be applied for other types of resonant converters, such as series resonant converter, parallel resonant converter and multi-phase resonant converter.