The reliability and lifespan of micro-inverters are two significant features of AC-module photovoltaic systems. One of the most effective methods to enhance the reliability and life duration of micro-inverters is achieved by substituting their electrolytic power decoupling capacitor with the film capacitors. In this study, a new DC/AC inverter based on an isolated singleended primary-inductance converter with an active clamp power decoupling is introduced. The proposed converter has no electrolytic capacitor which results in long lifetime and high reliability. Moreover, the inverter has simple structure and low number of semiconductor switches which improve the efficiency and make it cost effective. The sufficient stepping up ability for output voltage without increasing turns ratio excessively, non-pulsating input current, and appropriate isolation make the proposed micro-inverter a proper choice for grid-connected applications. The converter operating modes are discussed and design considerations are presented. Finally, experimental results of the implemented prototype validate aforementioned features and performance of the proposed micro-inverter.

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Here, a soft switched three-level boost converter with high voltage gain is proposed which is suitable for high step-up applications with wide output power range. In this converter, a ZVT auxiliary circuit is used which provides soft switching in a wide range of output power independent of load variation. Utilizing coupled-inductors with one magnetic core removes extra auxiliary core in the soft switching circuit and provides high voltage gain in conjunction with size reduction. Also, the secondary and tertiary leakage inductances of the coupled-inductors minimize the reverse recovery problem of the output diodes. Due to its three-level structure, it has very low voltage stress over semiconductor elements in comparison to the existing interleaved structures, resulting in using MOSFETs with low on-resistance and thus lower conduction losses and cost. Operating modes as well as analytical analysis of the proposed converter are discussed. Finally, in order to validate the proposed converter performance, experimental results from a 200-W laboratory prototype are presented.How to cite this article: Jazi, H.M., Fekri, M., Keshani, M., et al.: Soft-switching non-isolated high step-up three-level boost converter using single magnetic element.

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