A Novel Input-Parallel Output-Series SEPIC-Cuk Converter for Bipolar Voltage Balancing

Abstract

This article describes a novel Input-Parallel Output-Series SEPIC-Cuk (IPOSSC) converter formulated for application in low voltage bipolar DC microgrid (BDMG) systems. The proposed bi-directional converter adopts a single input dual output configuration with inherited common ground and employs an interleaved-structure to reduce source current fluctuations when linked to sustainable energy sources (SES) such as solar PV or energy storage elements (ESE) like batteries. The article includes the development of a dynamic model for this proposed circuit and formulates closed-loop controller for precise current and voltage regulation. Additionally, by integrating dispatchable sources like a battery into the source terminals, the IPOSSC can operate in voltage regulation mode to effectively control the bus voltage. Furthermore, the article explores an intriguing approach to counteract voltage unbalance in BDMG systems without relying on an active energy source connected to the source terminal. It harnesses the IPOSSC capabilities as a DC compensator, similar to an active shunt filter or D-STATCOM in AC systems, with the converter only incurring losses and not supplying or consuming power. The article substantiates the efficacy of the IPOSSC converter through simulation results depicting its performance in various operating modes. © 2023 IEEE.