Unified Control Scheme based on Model Predictive Control for Hybrid-Energy-Storage-based Microgrids

Abstract

This study proposes unified hierarchical control for power distribution among AC microgrids based on hybrid energy storage. In this study, each microgrid comprises hybrid energy storage (i.e., supercapacitor, battery, and hydrogen) and renewable power generator (i.e., photovoltaic module). The proposed hierarchical control framework ensures that power distribution among microgrids depends on the state of charge of hybrid storage in the given microgrids. The present study proposes an adaptive model predictive control based tertiary layer, which is responsible for the accurate power-sharing among the microgrids based on the individual state of charge of the storages in the given microgrids. The tertiary control layer generates the reference signals for the secondary control layer, where the pulse width modulation of the inverters in the respective microgrids is controlled. The primary control is responsible for the optimum power-sharing within individual microgrids based on the source, load, and state of charge of energy storage devices. The proposed unified hierarchical control for such a system is validated in different operating scenarios using power hardware-in-the-loop experiments. The proposed control scheme is very effective in smooth and controlled power exchange among microgrids during fuel cell operating mode. The proposed scheme also improves the DC bus regulation during transient power imbalances in microgrids.