Decentralized Control of a Hybrid AC and DC Ring Bus Microgrid System

摘要

Increasing use of renewable energy resources has created an environment for designing improved electric power distribution networks. Microgrid structures have received increased attention for being able to provide electric power to loads in the vicinity of renewable energy such as solar photovoltaic (PV) and wind turbine systems. Because solar PV and battery storage elements are dc sources, there is increased consideration given to developing hybrid ac and dc microgrid systems. Previous research has focused on simple radial feeder circuits for the interconnection of dc sources through power electronic inverter circuits. However, there are advantages to network or ring-configured buses in order to provide increased reliability in the event of a fault condition. Consequently, there is a need for developing methods for designing power electronic converters that control power flows in ring bus hybrid microgrids. This paper presents a method for modeling and designing a linear quadratic-based optimal decentralized control coordination scheme for power electronic inverter circuits. A detailed example is given for a 4 converter 480 V three-phase ac and 600 V dc microgrid based on the 6 MVA test facility at the National Center for Reliable Power Transmission (ncrept.uark.edu). Simulation results confirm the benefits of the proposed decentralized control method under a variety of solar PV transients.