A Novel Quadratic Buck–Boost Converter With Continuous Input Current and Reduced Voltage Stress on Power Components

Abstract

This study proposes a novel quadratic DC–DC buck–boost converter topology specifically designed for integration with renewable energy sources, such as photovoltaic systems. Owing to its quadratic voltage conversion characteristic, the proposed converter provides enhanced step‐up and step‐down capabilities compared to conventional buck–boost converters, particularly when operating under duty cycle conditions far from 50%. A critical review of existing quadratic buck–boost converter topologies indicates that voltage stress reduction is often achieved only partially, either on the MOSFET or on the diode, while the remaining device is subjected to high voltage stress, especially during boost mode operation at high duty cycles. To overcome these limitations, the proposed topology employs only two auxiliary capacitors to realize quadratic voltage gain while simultaneously maintaining low voltage stress on both the MOSFET and the diode over a wide operating range. This structural feature significantly reduces conduction and switching losses, thereby improving overall efficiency. In addition, the converter delivers a noninverting output voltage with a common ground reference between the input and output, facilitating seamless integration into unipolar systems. The proposed converter also ensures continuous current at both input and output ports, which is particularly advantageous for applications requiring stable power profiles. Notably, the converter achieves a unitary voltage gain at a duty cycle of 0.5 and offers a wide voltage conversion range in both buck and boost operating modes. A comprehensive mathematical analysis of the converter is presented, and the accuracy of the analytical results is validated through experimental studies, demonstrating close agreement between theoretical predictions and measured performance.