A Novel Reconfigurable Microgrid Architecture With Renewable Energy Sources and Storage

Abstract

This paper proposes a novel reconfigurable microgrid architecture comprising photovoltaic, wind, microhydro, and fuel cell based renewable energy sources. Transient and extended power backup are provided with ultra-capacitor (UC) and battery storage, respectively. A distinguishing feature of this microgrid is that its various control layers can switch roles during emergency. As renewable energy sources with significantly different dynamic behavior and dissimilar generating capacities are involved, disruptive effects such as voltage dips and fluctuations, frequency variation, and harmonic distortion are likely. This is handled through centralized monitoring in conjunction with hierarchical control. The reliability and sustainability of the resulting complex microgrid architecture is ensured through the proposed reconfigurable control and power network of the microgrid, supported by a hybrid communication layer comprising CAN, RS-485, and MODBUS protocols. The proposed architecture is strengthened by an additional “advisory” layer comprising an advisory controller that supports long-term optimization of microgrid operation under normal conditions and governs interim role assignments to control layers during crisis. All these special features ensure continuity of power with sustained performance or gracefully degraded performance even under various kinds of faults and abnormal events. Design of various controllers, protection, and reconfigurability features with relevant analysis and experimental results are presented.