Distributed control strategy for secondary frequency regulation with EV demand aggregation and delay compensation in AC unbalanced microgrid

Effective dispatch of ancillary services is a significant challenge for microgrids that incorporate renewable energy (RE), distributed generators (DG), and electric vehicles (EVs), due to uncertainties and communication delays during their operation. The secondary frequency regulation becomes a key task to restore the frequency to the set point through a load control strategy. This paper presents a cost-effective two-stage distributed energy management system (EMS) for microgrid operation to reduce reliance on battery storage systems and diesel generators, prolonging battery life and minimizing the use of expensive and polluting generators for secondary frequency regulation. Communication delays are addressed using an adjusted consensus ADMM algorithm, ensuring convergence. Additionally, a Stackelberg game framework is employed to design pricing at EV charging stations and incentivize customers to participate in secondary frequency control. An adaptive phase switching algorithm for phase switches is also proposed to ensure voltage phase balancing. Simulation results demonstrate an 8.98% reduction in cost deviation across stages, with a $234.46 profit by the EV aggregator during the intraday stage, considering secondary frequency regulation. The proposed approach offers a promising solution for efficient microgrid operation and effective integration of renewable energy and electric vehicles.