A Datasheet-Driven Electrothermal Averaged Model of a Diode-MOSFET Switch for Fast Simulations of DC-DC Converters

The design of modern power electronics converters requires accurate electrothermal device models enabling a straightforward parameter estimation and fast, yet accurate, circuit simulations. In this paper, a novel electrothermal averaged model of a diode-MOSFET switch for fast analysis of DC-DC converters is proposed. The model has the form of a SPICE-compatible subcircuit and allows computing in a very short simulation time the DC characteristics of the converter, the waveforms of the terminal voltages and currents of the semiconductor devices, as well as their junction temperatures, both in CCM and DCM.. All the input data required by the parameter estimation procedure can be taken from the datasheets of components. The correctness of the proposed approach is experimentally verified for a buck converter chosen as a case-study. A generally good agreement between measurements and simulations is obtained; as an example, the absolute error in assessing the MOSFET junction temperature does not exceed 12 degrees C within the whole range of switching frequency of the converter, while the commonly used PLECS model considerably underestimates it.