Note: This content is accessible to all versions of every browser. However, this browser does not seem to support current Web standards, preventing the display of our site's design details.

  

Breaking the Hierarchy: Distributed Control & Economic Optimality in Microgrids

Author(s):

F. Dörfler, J. W. Simpson-Porco, F. Bullo
Conference/Journal:

Abstract:

Modeled after the hierarchical control architecture of power transmission systems, a layering of primary, secondary, and tertiary control has become the standard operation paradigm for microgrids. Despite this superficial similarity, the control objectives in microgrids across these three layers are varied and ambitious, and they must be achieved while allowing for robust plug-and-play operation and maximal flexibility, without hierarchical decision making and time-scale separations. In this work, we explore control strategies for these three layers and illuminate some possibly-unexpected connections and dependencies among them. Building from a first-principle analysis of decentralized primary droop control, we study centralized, decentralized, and distributed architectures for secondary frequency regulation. We find that averaging-based distributed controllers using communication among the generation units offer the best combination of flexibility and performance. We further leverage these results to study constrained AC economic dispatch in a tertiary control layer. Surprisingly, we show that the minimizers of the economic dispatch problem are in one-to-one correspondence with the set of steady-states reachable by droop control. In other words, the adoption of droop control is necessary and sufficient to achieve economic optimization. This equivalence results in simple guidelines to select the droop coefficients, which include the known criteria for power sharing. We illustrate the performance and robustness of our designs through simulations.

Year:

2014
Type of Publication:

(15)Miscellaneous
Supervisor:



File Download:

Request a copy of this publication.
(Uses JavaScript)
% Autogenerated BibTeX entry
@Misc { D_rSim:2014:IFA_4939,
    author={F. D{\"o}rfler and J. W. Simpson-Porco and F. Bullo},
    title={{Breaking the Hierarchy: Distributed Control \& Economic
	  Optimality in Microgrids}},
    month=jan,
    year={2014},
    url={http://control.ee.ethz.ch/index.cgi?page=publications;action=details;id=4939}
}
Permanent link