System Analysis and Design for Multiconverter Electrical Power Systems in Nanosatellites

For low-Earth orbit nanosatellite development, small volume and high reliability are of primary concern. The electrical power system (EPS) is a critical subsystem that generates, stores, and distributes power within the nanosatellite. An EPS is typically made up of multiple power converters that are designed independently and then connected together. However, if the impedance interactions of the power converters are not properly analyzed, the converters can interact adversely in some conditions, leading to instability. Analyses using the impedance interaction factor and the extra element theorem are applied to the EPS. A design procedure and analysis tool, developed in MATLAB, is presented to ensure a robust EPS without converter interaction stability problems. A CubeSat EPS hardware prototype with four buck converters powered by photovoltaic panels is tested to verify the impedance analysis and stable system operation of the nanosatellite EPS.