Multiple Control Strategies for Distributed Battery Energy Storages in Microgrid DC Fast Charging Stations to Improve Load Voltage Variations, Mutual Power Exchange with the Grid and Islanded Mode Operation

On highways and at the end of distribution feeders, DC fast charging stations (DCFCs) are commonly located. As a result, charging electric vehicles (EVs) at these stations results in a reduction in power quality, including a drop in network voltage. This paper proposes an integrated control system for DCFCs utilizing microgrid (MG) capabilities. The voltage drop problem is addressed using two simultaneous methods in the proposed control systems, including reactive power injection by the MG and reducing the network’s active power consumption by installing distributed battery energy storage (DBES) devices. Furthermore, the control system aims to enhance the performance of the combined MG-DCFC system when operated off-grid. A nonlinear time domain simulation of the proposed control systems is carried out in MATLAB/SIMULINK environment. The results show that the proposed solution can effectively control the integrated MG and DCFC under normal and critical operating conditions, enabling participation in the main power markets and ancillary services.