Optimized Control of the Distributed DC Energy System in a Building Considering Bidirectional EV Charging

Grid-friendly buildings can actively participate in the coordination and interaction of the power grids, primarily by flattening the building demand profile. The increasing penetration of the renewable power generation and the disorderly electric vehicles charging bring new challenges to building energy control. To achieve a flattened building power demand profile, researchers have paid efforts on developing the peak shaving and valley filling strategies. However, the potential of bidirectional electric vehicles charging strategy to enhance the grid friendliness has not been considered. Therefore, this study proposes an optimized control method for a distributed direct current (DC) energy system in buildings that integrates the battery storage system, the photovoltaic, and the electric vehicles. This method considers the bidirectional EV charging strategy, aiming to flatten the building power load curve. Three strategies were evaluated and compared to show the suboptimal performance of the rule-based strategy in relieving grid pressure caused by the building peak-to-valley difference and load curve flatten. Results also demonstrated that the improved performance of the proposed control in terms of peak demand limiting and curve flatten.