This paper proposes a new transformerless buck-boost converter with an extended voltage conversion ratio. This converter has semi-quadratic voltage gain, which provides more gain with lower duty cycles. This converter has a simple structure and easy implementation, which reduces the cost and increases efficiency. The proposed converter operates in continuous conduction mode and provides two operation modes by turning on and off the switches. The suggested converter has continuous input current and low input current ripple, which is important when utilizing renewable energy sources. The calculation of the proposed converter includes ideal and practical voltage gain, current calculations, voltage stresses of the switches and diodes, current stress of the switches, parameter design, efficiency, and a brief analysis of discontinuous conduction mode and boundary conditions. The proposed converter provides efficiency of about 93.1% in boost mode and 92.14% in buck mode at 50 W output power. The suggested converter varies the input voltage from 20 to 48 V in boost mode and changes the input voltage from 20 to 10.4 V in buck mode. Finally, a laboratory prototype has been built to prove and evaluate the simulation results and theoretical analysis of the proposed converter.

中文翻译：

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新型无变压器降压-升压转换器，具有改进的电压增益和连续输入电流

本文提出了一种具有扩展电压转换比的新型无变压器降压-升压转换器。该转换器具有半二次电压增益，可以以更低的占空比提供更大的增益。该变换器结构简单，易于实现，降低了成本，提高了效率。所提出的转换器以连续导通模式工作，并通过打开和关闭开关提供两种工作模式。建议的转换器具有连续输入电流和低输入电流纹波，这在利用可再生能源时非常重要。所提出的转换器的计算包括理想和实际电压增益、电流计算、开关和二极管的电压应力、开关的电流应力、参数设计、效率以及对不连续导通模式和边界条件的简要分析。在 50 W 输出功率下，所提出的转换器在升压模式下提供约 93.1% 的效率，在降压模式下提供约 92.14% 的效率。建议的转换器在升压模式下将输入电压从 20V 更改为 48V，在降压模式下将输入电压从 20V 更改为 10.4V。最后，建立了一个实验室原型来证明和评估所提出的转换器的仿真结果和理论分析。