A Negative Imaginary Approach for Distributed Secondary Frequency Consensus Control of Networked AC Microgrids
Arijit Ganguly, Adino Worku Ayele, Parijat Bhowmick, Alexander Lanzon · 2023
This paper proposes a new Secondary Frequency Consensus (SFC) control scheme for inverter-based AC microgrids relying on Negative Imaginary (NI) systems theory. A microgrid consists of many Distributed Generating (DG) units whose dynamics can be modelled by a set of nonlinear differential-algebraic equations. Each DG can be feedback-linearised into a single integrator system, which resembles the simplified frequency dynamics of a microgrid. A network of many such feedback-linearised DG units gives rise to a homogeneous NI multi-agent system (MAS). Interestingly, a single-integrator MAS, owing to be NI, can be conveniently stabilised by a distributed Strictly NI (SNI) controller depending only on the definiteness of the DC gain matrix of the controller. It also successfully achieves the consensus, resulting in frequency synchronisation among all DG units and the main grid. An in-depth Matlab simulation case study was carried out to test the usefulness and performance of the proposed scheme.