Power Talk for Multibus DC MicroGrids: Creating and Optimizing Communication Channels

TL;DR

This paper introduces a power talk communication method for multibus DC MicroGrids, modulating reference voltages to enable data exchange while optimizing system parameters for improved signal quality and power constraints.

Contribution

It proposes a novel power talk framework for multibus DC MicroGrids, modeling communication channels and optimizing virtual resistances to enhance SNR under power constraints.

Findings

Linear approximation of communication channels based on control parameter deviations

Optimized virtual resistances improve received SNR

Power deviations impose constraints on control parameters

Abstract

We study a communication framework for nonlinear multibus DC MicroGrids based on a deliberate modification of the parameters of the primary control and termed power talk. We assess the case in which the information is modulated in the deviations of reference voltages of the primary control loops and show that the outputs of the power talk communication channels can be approximated through linear combinations of the respective inputs. We show that the coefficients of the linear combinations, representing equivalent channel gains, depend on the virtual resistances of the primary control loops, implying that they can be modified such that effective received signal-to-noise ratio (SNR) is increased. On the other hand, we investigate the constraints that power talk incurs on the supplied power deviations. We show that these constraints translate into constraints on the reference voltages and virtual resistances that are imposed on all units in the system. In this regard, we develop an optimization approach to find the set of controllable virtual resistances that maximize SNR under the constraints on the supplied power deviations.