Temperature Dependent Characterization-based Design Optimization of a DC-DC Converter for High-Temperature Applications

This paper demonstrates the design procedure of a wide voltage gain non-inverting buck-boost converter (NIBB) for high temperature (>150°C) application utilizing the bare die Silicon Carbide (SiC) technology. This work evaluates the ability of SiC bare dies for high temperature (>150°C) power electronics. The selection of the passive components in the power stage such as inductor and capacitors are performed by evaluating a temperature dependent characterization of their performance metrices such as permeability, inductance, leakage current and capacitance. To minimize the temperature rise of the SiC MOSFETs under the full load operation, a quantitative design optimization is performed on the inductance value while accounting for switching and conduction losses and checking for full soft-switching constraints to attain the global minima in total power loss at the switches. A 100W converter prototype is fabricated and tested that converts the input side battery voltage levels of 28V, 120V, and 160V to a configurable output voltage from 30V to 48V, used as a standard for space missions. The experimental result shows a peak conversion efficiency of 91.3% at 200°C ambient temperature. The average full load efficiency of 88.2% at maximum ambient operating temperature validates the proposed design optimization procedure and also makes the SiC bare die technology a suitable candidate for this high temperature application.