Design Considerations for a Gallium Nitride Based Phase Shifted Full Bridge DC-DC Converter for Space Applications

The main design considerations for the practical implementation of a Phase Shifted Full Bridge DC-DC converter with synchronous rectification using recently released radiation hardened Gallium Nitride (GaN) Field Effect Transistors (FETs) for space applications are presented in this paper. A brief survey comparing the benefits of GaN FETs for space power applications against current Silicon power transistor technology is conducted. Also, the main drivers for topology selection, and design considerations to implement the selected topology for space applications resulting from the limited radiation hardened components available today are described in detail. In addition, power loss breakdown from analysis and final design choices are presented. A converter was designed to validate design based on the considerations outlined. The implemented converter operates from a 100 V DC bus and delivers 400 W from a fixed 20 V output at more than 95% efficiency.