Principal Investigator: Dr. Yue Zhao
Grid-tied inverters, which are widely used as the interface between the DERs and grids, still need to generate high quality output power and ensure stable operation when connected to the microgrid systems, which represent more complicated grid-side impedance compared to the traditional grids. In this project, a novel output impedance shaping approach is proposed to eliminate the harmonics and improve output power quality of the grid-connected inverters, especially when they connected in the microgrid systems. The stability and power quality requirements are the two major constraints in the output impedance profile design and optimization. The inverter controller can be further designed based on the guidance of the output impedance. In addition, when multiple inverters are working in parallel in the microgrid, the output impedance shaping scheme can provide an additional degree-of-freedom to attenuate the circulating current, as the inverter output impedance could be actively adjusted, such that both the system efficiency and the reliability can be further enhanced.