A high efficiency unidirectional DC/DC converter for integrating distributed resources into DC microgrids

Abstract

This paper presents a novel unidirectional DC/DC converter that can be used to transfer power from distributed resources such as Solar PV or Fuel Cells into a DC microgrid. The converter is based on the LLC topology but designed to operate in a specific region of the gain curve that provides several benefits to integration of renewable energy sources into a constant DC bus. The isolated converter shows very high efficiency, full range of zero current switching, and simple control. The novel topology also has the inherent attribute of balancing the voltage on a bipolar DC bus by automatically shifting the processed power to the pole with the lower voltage.