A self-adaptive communication-free control scheme of islanded PV-storage microgrids

For the problem that traditional droop control cannot maintain the maximum output power of photovoltaic (PV) units, this work proposes a self-adaptive communication-free control scheme for the islanded PV-storage AC microgrids. The proposed control enables the maximum power point tracking-based output active powers of PVs by adaptively adjusting P-f/Q-V droop coefficients. It also facilitates adaptive allocations of reactive powers based on the available capacities of PVs and storage modules. The key characteristics of the proposed control strategy are summarized as follows: 1) PV units are controlled as voltage sources, which could participate in the voltage/frequency regulation to a certain extent; 2) maximum power utilization of PVs is obtained; 3) adaptive allocations of reactive powers are realized based on the maximum available capacity of PVs and storage modules. Subsequently, the stability analysis of the proposed self-adaptive communication-free control strategy is verified. Finally, the validity of the proposed self-adaptive communication-free control method is validated through simulations conducted using MATLAB/Simulink.