Practical Implementation and Efficiency Evaluation of a Phase Shifted Full Bridge DC-DC Converter Using Radiation Hardened GaN FETs for Space Applications

The practical implementation and efficiency evaluation of a Phase Shifted Full Bridge DC-DC converter for space applications using 200 V, 18 A, radiation hardened Gallium Nitride (GaN) Field Effect Transistors (FETs) are presented in this paper. Design considerations for topology selection and auxiliary circuitry resulting from constraints currently encountered in power electronics for space applications are briefly described. In addition, the process followed to design the power stage, as well as the effects of resonant inductance and transformer design on converter performance are presented. Furthermore, a hard-switched Full Bridge DC-DC converter was implemented to study the performance differences with the phase shift modulated converter. Both DC-DC converters deliver 500 W at a 20 V regulated output from a 100 V nominal DC bus. The Phase Shifted Full Bridge DC-DC converter presented in this paper achieves more than 95% peak efficiency at its nominal operating point, with an initial prototype power density of 79 W/inch³ obtained.