Power talk is a novel concept for communication among control units in
MicroGrids (MGs), carried out without a dedicated modem, but by using power
electronics that interface the common bus. The information is transmitted by
modulating the parameters of the primary control, incurring subtle power
deviations that can be detected by other units. In this paper, we develop power
talk communication strategies for DC MG systems with arbitrary number of
control units that carry out all-to-all communication. We investigate two
multiple access strategies: 1) TDMA, where only one unit transmits at a time,
and 2) full duplex, where all units transmit and receive simultaneously. We
introduce the notions of signaling space, where the power talk symbol
constellations are constructed, and detection space, where the demodulation of
the symbols is performed. The proposed communication technique is challenged by
the random changes of the bus parameters due to load variations in the system.
To this end, we employ a solution based on training sequences, which
re-establishes the signaling and detection spaces and thus enables reliable
information exchange. The presented results show that power talk is an
effective solution for reliable communication among units in DC MG systems.Comment: Multiuser extension of the power talk concept. Submitted to IEEE JSA
