A Redundant Power Bus for Distributed Power Management for a Modular Satellite

Paper number

IAC-09.C3.2.8

Author

Prof. Leonardo M. Reyneri, Politecnico di Torino, Italy

Coauthor

Prof. Leonardo M. Reyneri, Politecnico di Torino, Italy

Coauthor

Prof. Dante Del Corso, Politecnico di Torino, Italy

Coauthor

Mr. Stefano Speretta, Politecnico di Torino, Italy

Year

2009

Abstract

The paper presents a novel Power Bus to be used in modular satellites,
namely all those satellites which are built from a number of simple and identical
modules to reduce development, manufacturing, integration and testing costs.

The idea behind the proposed Power Bus is to have power conversion (from solar panels)
and power storage (in Li-Ion batteries) distributed all over several Power Management
modules (the so-called ``tiles'') which contain, each: a solar panel; energy storage
batteries with the corresponding power converters; a programmable power sink.

The proposed Power Bus is such as to allow direct connection of as many modules
as required (to adapt system performance to the requirements), either in parallel 
(to increase current) or in series (to increase voltage) or both,
while allowing a number of power management functions to be handled in a
distributed way. For instance: i) accumulating the power from all solar panels
towards the load(s); ii) accumulating the power to charge one or more distributed
batteries; iii) transferring the unused power towards a user-selectable sink
(usually on the coldest surface); iv) appropriate mixtures of the above; v) other
functions like housekeeping and telemetry.

All the functions are implemented in a distributed way, with very limited
centralized control (sometimes, even no centralized control), where each
subsystem connected to it (namely: the solar panel with its MPPT converter;
the batteries; the load(s); the power sink; the overvoltage protection)
has appropriate characteristics which allow self-controlled
distribution of electrical power and appropriate distributed load balancing.

System stability is guaranteed by the proposed characteristic of each subsystem
in such a way that any number of modules can be connected to the bus without
impairing overall performance and stability.

The performance of the bus depend on the characteristics of each module.
A specific implementation is also addressed where each module has a 15x15cm2
solar panel and two Li-Ion rechargeable batteries, offering 15W continuous
power and about 15Wh storage capability, allowing max 120V, 20A, 2.5kW for the
load.

The proposed Power Bus can easily be made double-redundant to increase system
reliability at a very limited cost.
In addition, the bus is conceived to be tolerant to single faults (with at most
a graceful degradation in case of one or more faults).

Abstract document

IAC-09.C3.2.8.pdf

Manuscript document

IAC-09.C3.2.8.pdf (🔒 authorized access only).

To get the manuscript, please contact IAF Secretariat.