A Smart Grid Control Strategy for Improved Power Efficiency

Abstract

Korea has been experiencing power demand supply problems during summer and winter. We aim to solve these problems by mitigating the difference of supply and demand power amount. This thesis presents a smart grid control strategy for improved power effi-ciency using energy storage devices of a microgrid system. The microgrid system is the combination of a photovoltaic (PV) array, loads, and a battery energy storage system (ESS) via a DC bus. The control strategies were defined as multi-modes of operation, in-cluding a rest operation without use of battery, power charging, and power discharging, which enables either a grid connected mode or an islanded mode. A supervisory control regulates power generation of the individual components so as to enable the microgrid sys-tem to operate in the proposed modes of operation. The concept and principle of the mi-crogrid system and its control were described. In the battery converter, state-feedback con-trol is used to discharge power as user wants. Modeling and simulation were based on MATLAB/Simulink. A 100-kW microgrid inverter and its control system were developed. The simulation results were presented to evaluate the dynamic performance of the mi-crogrid system under the proposed modes of operation. ⓒ 2014 DGIST