Networked Control of Distributed Energy Resources Using an Adaptive Communication Policy

Abstract

This work presents a model-based networked control structure with an adaptive communication policy for managing Distributed Energy Resources (DERs) over a shared, resource-constrained communication network. The central objective is to find a state-dependent strategy for establishing and terminating communication between the supervisor and the DERs in a way that minimizes network resource utilization without jeopardizing the desired stability and performance properties. To this end, a bounded robust Lyapunov-based controller that enforces constrained closed-loop stability in the absence of communication suspension is initially designed for each DER. A dynamic model of each DER is then included within the supervisor to provide estimates of the states of the DER when measurements are not transmitted through the network. To determine when communication between a given DER and the supervisor must be re-established, the evolution of the Lyapunov function is monitored within the DER's stability region such that if it begins to breach a state-dependent stability or performance threshold at any time, the sensor suite is prompted to send its data over the network to update its corresponding model in the supervisor. Communication is then suspended for as long as the Lyapunov function satisfies the specified threshold. The underlying idea is to use the Lyapunov stability constraint for each DER as the basis for adaptively switching on or off the communication with the supervisor. Finally, the results are illustrated through an application to a solid oxide fuel cell example.