Modular Power System: Enabling Scalable Missions for the 1W to 1kW Range

As small satellites are increasingly tasked with more aggressive and responsive missions, the utility of scalable, modular and standardized avionics has become evident. A power system offering standard interfaces, with high efficiency across wide power throughput ranges, and late-stage expandability is clearly advantageous for a wide range of missions, particularly responsive ones. In order to address this need, the University of Toronto Space Flight Laboratory (SFL) has developed a modular power system (MPS) to facilitate missions with power requirements spanning two orders of magnitude. The presented case study on the modular power system consists of various modules responsible for power conversion and load switching. A central backplane enables the various MPS modules, as well as mission specific modules to either draw from or energize distributed power buses and interface to the systems digital communication busses. The MPS is designed to provide “only as much power system as needed", and the ultra-high efficiency of each card makes the system suitable for missions ranging from the 1-10W nanosatellite class (such as SFL's CanX-7) to the 100-500W class microsatellite (such as SFL's NEMO-HD). The first MPS deployment, on the Canadian Space Agency's Mars Exploration Science Rover (MESR), developed by MacDonald Dettwiler and Associates Ltd., was configured to run sustained loads of 1.3 kW. This paper provides a high-level overview of the MPS, how the system can be configured for missions ranging from cubesats to kW-class small spacecraft, and the impact modular avionics have on the rest of the satellite system.