Identification of control and management strategies for LV unbalanced microgrids with plugged-in electric vehicles

This paper addresses issues concerning the integration of single-phase charging devices for electric vehicles (EV) in low-voltage microgrids. Fast release energy storage is a key issue for microgrid islanding operation. EV batteries provide an additional storage capacity, which can now be exploited in order to improve MG islanding. Aiming to do so, different control strategies were developed and tested: (1) a local control approach where no communication link is required and (2) a centralized charging control solution. The local control approach is based on the measuring of EV terminal voltage and frequency in order to define the charging or discharging rates of the batteries. The centralized control strategy allows balancing single-phase loads connected to the microgrid by adapting the charging rates of the EV storage devices. Simulation results show that EV batteries can actively contribute for voltage balancing and frequency control during islanding operating conditions.