High gain inverters are gaining popularity due to their application in renewable energy sources. Impedance source inverters (ISIs) such as Z-source inverter (ZSI) and its derivatives are favored over the two-stage boost-VSI topology because of their higher gain and better EMI immunity. Another ISI, Current-fed Switched Inverter (CFSI), has a similar gain characteristic as ZSI but with lesser components. The major drawback of high gain inverters is that they draw very high input current. Thus, the switching and conduction losses increase in the front stage converter, resulting in reduced efficiency. This paper proposes a modified CFSI topology to achieve Zero Current Switching (ZCS) of the switch connected in the front-end boost stage. The operating principle and modes of operation of the proposed converter are discussed in detail. A flow chart for designing the resonating components of the modified circuit and the impact of parametric variation on the scheme's performance is reported. The theoretical analysis is verified with the help of a laboratory prototype. The efficiency of the modified converter is found to be increased by 2% (at 450 W load) compared to conventional CFSI.

中文翻译：

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一种零电流开关非隔离高增益逆变器的分析与设计

高增益逆变器因其在可再生能源中的应用而越来越受欢迎。阻抗源逆变器 (ISI)，例如 Z 源逆变器 (ZSI) 及其衍生产品，比两级升压 VSI 拓扑更受青睐，因为它们具有更高的增益和更好的 EMI 抗扰度。另一种 ISI，即电流馈电开关逆变器 (CFSI)，具有与 ZSI 相似的增益特性，但组件较少。高增益逆变器的主要缺点是它们吸收非常高的输入电流。因此，前级转换器中的开关和传导损耗增加，导致效率降低。本文提出了一种改进的 CFSI 拓扑，以实现前端升压级中连接的开关的零电流开关 (ZCS)。详细讨论了所提出的转换器的工作原理和工作模式。报告了设计改进电路的谐振元件的流程图以及参数变化对方案性能的影响。理论分析在实验室原型的帮助下得到验证。与传统的 CFSI 相比，改进后的转换器的效率提高了 2%（在 450 W 负载下）。