Stored energy balance for distributed PV-based active generators in an AC microgrid

Abstract

In this paper, a decentralized strategy based on fuzzy logic is proposed for balancing the state of charge of the energy storage units for distributed PV-based active generators. The proposed method, weights the action of conventional droop control loops for privileging the charge of the energy storage unit with the smallest state of charge or force a faster discharge of the energy storage system with the biggest state of charge. The units are self-controlled by using local variables, hence, the microgrid can operate without relying on communication systems. The proposed strategy is completely expandable and can be applied to a several number of power generators interconnected in a microgrid. Frequency and voltage bus signaling is used in order to coordinate the control operation mode between units. Simulation results in a low-voltage, three-phase, islanded AC microgrid show the feasibility of the proposed method and its applicability even for several active generators.