Enhancing grid-friendliness in PV building clusters via a coordinated control strategy integrating bidirectional electric vehicle charging

The increasing penetration of electric vehicles (EVs) and the large-scale integration of distributed renewables impose significant challenges to the stability of power grids. Enhancing the grid-friendliness of building clusters is critical to supporting the secure and reliable grid operations. Conventional building cluster-level control strategies primarily focus on peak shaving, which lowers the peak demand but fails to address the fluctuations in the power demand profiles. To overcome these limitations, this study proposes a coordinated control strategy integrating bidirectional EV charging to flatten the power demand profiles for a building cluster with PV, batteries and EVs. Unlike existing cluster-level control strategies, the proposed control strategy shifts the control objective from the peak shaving to the power flattening, while integrating the bidirectional EV charging. This strategy jointly optimizes the operations of stationary batteries and bidirectional EV charging, aiming to minimize the peak-to-valley difference (PVD) and the variance (VAR) of the aggregated power demand. A case study involving three buildings is conducted to evaluate its effectiveness against three conventional strategies. Results show that the proposed control strategy (Strategy #4) stands out as the optimal strategy, achieving significant improvements in grid-friendliness at the building cluster level. It achieves a 39% greater reduction in the PVD and a 9% greater reduction in the VAR compared to Strategy #1 (i.e., uncoordinated control with uncontrolled EV charging). It achieves an additional 34% reduction in the PVD and 4% reduction in the VAR compared to Strategy #3 (i.e., coordinated control with uncontrolled EV charging).