A hybrid high-gain bipolar converter for LVDC microgrid with average current mode control

Abstract

The increasing demand for renewable energy accounts for the DC microgrid concept, facilitating the integration of photovoltaic (PV) modules and battery energy systems (BESS) into a common DC bus. In light of this, bipolar DC-DC converters can result in two symmetric DC buses that provide more flexibility. This article presents a hybrid bipolar converter by merging a single-ended primary-inductor converter (SEPIC) and a Cuk converter with a switched-inductor configuration in lieu of the input inductors for gain enhancement. The architecture holds the advantages of both the SEPIC and Cuk converters and has one active switch, resulting in a simple control circuitry. Incorporating the average current mode (ACM) control strategy, the proposed converter is capable of providing a bipolar output, each having a higher voltage gain than the conventional converters. A 510 W prototype, validated in a power hardware-in-the-loop (PHIL) laboratory environment, demonstrated a peak efficiency of 97.14 %, close to the theoretical projection of 99 %. The proposed topology contributes to advancing clean energy technologies by enabling efficient and reliable energy conversion for renewable-based microgrids.