Stability and Control of Ad Hoc DC Microgrids

TL;DR

This paper develops stability conditions and decentralized control strategies for ad hoc DC microgrids, enabling reliable, autonomous operation in unplanned, user-assembled electrical networks.

Contribution

It introduces a novel decentralized control scheme and applies nonlinear control techniques to ensure stability and power management in ad hoc microgrids.

Findings

Derived conditions for stable equilibrium points.

Proposed a decentralized power dispatch control scheme.

Validated approach through simulation comparisons.

Abstract

Ad hoc electrical networks are formed by connecting power sources and loads without pre-determining the network topology. These systems are well-suited to addressing the lack of electricity in rural areas because they can be assembled and modified by non-expert users without central oversight. There are two core aspects to ad hoc system design: 1) designing source and load units such that the microgrid formed from the arbitrary interconnection of many units is always stable and 2) developing control strategies to autonomously manage the microgrid (i.e., perform power dispatch and voltage regulation) in a decentralized manner and under large uncertainty. To address these challenges we apply a number of nonlinear control techniques---including Brayton-Moser potential theory and primal-dual dynamics---to obtain conditions under which an ad hoc dc microgrid will have a suitable and asymptotically stable equilibrium point. Further, we propose a new decentralized control scheme that coordinates many sources to achieve a specified power dispatch from each. A simulated comparison to previous research is included.