Comparison of Si and GaN Power Devices Based SMPS for Satellite Application

Gallium Nitride(GaN) power devices offer benefits like faster switching, lower on-resistance, lower device capacitances as compared to the current silicon(Si) devices. These benefits could be leveraged to reduce the size and weight of GaN based power electronic supplies. This paper aims to evaluate the benefits and challenges of using GaN devices by experimentally comparing Si and GaN based Switch Mode Power Supply(SMPS) for satellite application. Two multi output flyback converter prototypes with Si and GaN switches are developed for the same specifications to observe the direct benefits and challenges of using GaN switches. It is observed that for same efficiency, GaN converter can have upto 10 times the switching frequency as compared to a Si converter. This results in significant reduction in capacitor and inductor size, resulting in a two fold improvement in overall power density. Further, this paper also discusses the issues arising from high frequency switching in presence of circuit parasitics.