Session
Technical Session VI: Small but Mighty
Abstract
Historically, cubesats have used a centralized Electrical Power System (EPS) wherein regulated and unregulated voltages are bused throughout the cubesat eliminating the need for further regulation. Typical EPS designs for larger spacecraft, almost always use a distributed architecture for the EPS. A high voltage, un-regulated or regulated, is distributed to the subsystems. These subsystems regulate the higher voltage to the required lower voltages required by the electronics. This distributed architecture was found to be difficult to scale when the satellite design shrunk from hundreds of kilograms and kilowatts down to handfuls of each. Regulators can be optimized for non-varying loads. The more fluctuation in the load, the greater your inefficiencies become for the specific fixed point regulator. The designer must size the regulator to meet the highest load demand plus margin. This usually means the operating point, for the majority of the load cases, is far down on the efficiency curve. Thus, regulators that are specified at greater than 90% may in reality be operating at less than 60% in many cases. This paper investigates the use of high efficiency point of load converters, commonly available on the commercial market, in a distributed architecture for cubesat implementation.
Presentation Slides
Distributed EPS in a CubeSat Application
Historically, cubesats have used a centralized Electrical Power System (EPS) wherein regulated and unregulated voltages are bused throughout the cubesat eliminating the need for further regulation. Typical EPS designs for larger spacecraft, almost always use a distributed architecture for the EPS. A high voltage, un-regulated or regulated, is distributed to the subsystems. These subsystems regulate the higher voltage to the required lower voltages required by the electronics. This distributed architecture was found to be difficult to scale when the satellite design shrunk from hundreds of kilograms and kilowatts down to handfuls of each. Regulators can be optimized for non-varying loads. The more fluctuation in the load, the greater your inefficiencies become for the specific fixed point regulator. The designer must size the regulator to meet the highest load demand plus margin. This usually means the operating point, for the majority of the load cases, is far down on the efficiency curve. Thus, regulators that are specified at greater than 90% may in reality be operating at less than 60% in many cases. This paper investigates the use of high efficiency point of load converters, commonly available on the commercial market, in a distributed architecture for cubesat implementation.
