Single Point Failure Free Interleaved Synchronous Buck Converter for Microsatellite Electrolysis Propulsion

This article describes the design and implementation of a dc–dc converter used to power a microsatellite on-board electrolyzer. The proposed topology is a four-phase interleaved synchronous buck converter with output current control. The proposed converter is single point failure free (SPFF), so in case of any individual component failure, the functionality of the system is not compromised. SPFF operation is achieved using individual protections in each buck phase, redundant output current control, and redundant clock systems. Besides, analog majority voter circuits are used to select the correct control signal after any failure and to isolate it. Detailed mathematical analysis and circuit design are presented. Furthermore, a 40-W prototype has been implemented to validate the concept. Experimental results presented show the correct performance of the system in every case and its fault tolerant capability. In addition, the ac behavior and stability of the system have been studied and verified under the full range of possible operating conditions. Finally, efficiency measurements are presented.