Optimal PEV Charging and Discharging Algorithms to Reduce Operational Cost of Microgrid Using Adaptive Rolling Horizon Framework

This paper presents an optimal operation algorithm for a grid-connected microgrid that incorporates renewable energy sources (RESs), plug-in electric vehicle (PEV) charging/discharging stations, and local loads. The aim of this work is to not only propose a microgrid operating algorithm but also implement it within the microgrid energy management system. The primary objective of the proposed algorithm is to reduce the overall operational cost of the microgrid while minimizing the PEV charging bills simultaneously. To this end, we propose an adaptive PEV power charging/discharging and power exchange (grid exporting/importing) scheduling strategy that accounts for the uncertainty of RES power generation, loads, and electric pricing. To address the dynamic arrival of PEVs, we propose an online optimization scheme using an adaptive rolling horizon framework. The size of the rolling window is adjusted in each time step to adapt to the dynamic nature of the PEV charging period. Additionally, we propose the design of a dynamic pricing model for PEV charging and discharging to achieve power system balance within the microgrid, thereby optimizing operating costs and minimizing PEV charging bills further. Through simulations, we demonstrate the effectiveness of the proposed strategies, which are expected to benefit both the microgrid operators and PEV owners.