Coordinated Power Control for Islanded DC Microgrids Based on Bus-Signaling and Fuzzy Logic Control

In an islanded dc microgrid consisting of multiple photovoltaic (PV) generators, energy storage system (ESS) and loads, a coordinated power regulation is critically important to avoid the state-of-charge (SOC) and charging/discharging power of ESS from exceeding their limits while making full use of renewable energy. In this study, a decentralized coordinated power control approach is proposed with considering the limits of maximum charging/discharging power of ESS to achieve power management for islanded dc microgrids. The proposed control strategy is implemented by combining the dc bus voltage signaling with fuzzy logic control and can operate without the need for communication lines. When designing the fuzzy logic controller, in addition to the SOC, the charging/discharging power of ESS is also taken into account to keep both the SOC and power of ESS within the desired ranges. Then, the power limiting controller is designed for PV generators to curtail PV power when bus voltage is high. The fuzzy logic controller changes the bus voltage to make the output power of PV generators decrease or perform the load shedding. Based on the proposed method, the generation-storage-load coordination can be achieved to satisfy different usage scenarios. Finally, the effectiveness of proposed algorithm is verified by the Matlab/Simulink simulation results under different test scenarios.