부산대학교 도서관

Microgrid provides an opportunity for integrating renewable energy sources at distribution side, leading to enhancement in reliability, sustainability and efficiency of the power system. Currently, DC microgrids are becoming popular due to reduction in power conversion stages and simpler control methods. Standalone DC microgrids are prominent in remote areas, spacecraft and shipboard applications. Due to the intermittent nature of renewable energy sources, reliability of supplying power in standalone systems depend on capacity of energy storage. But increasing the storage capacity incurs more cost and maintenance. To overcome this neighbouring microgrids are interconnected. In this work, a novel hierarchical power control strategy using cloud infrastructure that optimally utilizes all the resources in the microgrids is proposed. Each standalone DC microgrid consists of solar PhotoVoltaic (PV) systems, fuel cell, battery, supercapacitor and load. The voltage, current and power of each unit in the microgrid are transmitted to the cloud server. The power mismatch which is the difference between intermittent power from PV and load power is determined and then optimally allocated to battery, fuel cell and supercapacitor. The control strategy also facilitates microgrid clusters as well as plug and play services. Simulation of interconnected microgrid system is carried out using MATLAB/Simulink to verify the proposed control strategy.