Novel Isolated Multiport DC Converter with Natural Bipolar Symmetry for Renewable Energy Source Integration to DC Grids

Abstract

Due to their greater reliability, efficiency, and resilience as compared to unipolar dc grid systems, bipolar dc grid systems are swiftly gaining popularity for the integration of renewable energy sources. However, development of multiport converters for bipolar microgrid systems is still progressing slowly in terms of reducing costs or improving power density and compact designs. This paper proposes a multiport isolated dc-dc converter with naturally symmetric bipolar outputs (MIBDC). With respect to the number of input ports, voltage gain, and output symmetry that the proposed converter naturally possesses, it outperforms its few competitors. Additionally, the proposed MIBDC significantly reduces component count and control complexity by employing a fixed transformer with only one primary and secondary winding for any number of inputs. The suggested converter's performance in both open and closed loops is evaluated quantitatively in simulation and experimentally using OPAL-OP5700 RT's hardware-in-the-loop (HIL) platform under various situations.