Hierarchical Supervisory Control System for PEVs Participating in Frequency Regulation of Smart Grids

This paper proposes a two-level hierarchical supervisory control system for plug-in electric vehicles (PEVs) participating in frequency regulation in microgrids with interconnected areas. At the lower level, decentralized fuzzy logic control systems are designed for individual PEVs which locally adjust the V2G power flow rates from each vehicle to the grid according to the frequency deviation in each area and the vehicle's current state of charge (SOC), while maintaining the SOC level above the driver's requested SOC lower limit. At the grid level, a centralized supervisory control system is used to coordinate the injected power from generating units and PEVs based on the grid demand. Simulation results are presented and analyzed to investigate the performance of the proposed two-level system in a network consisting of three interconnected areas populated with PEVs under load disturbances and wind power fluctuations.