Soft-switching non-isolated high step-up three-level boost converter using single magnetic element

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.Peer ReviewedPostprint (published version

An Interleaved Soft Switched High Step-Up Boost Converter With High Power Density for Renewable Energy Applications

In this article, a novel soft switched interleaved boost structure with a simple auxiliary circuit is proposed which is suitable for stand-alone loads or ac grid applications. In this topology, coupled inductors and switched capacitor cells of parallel modules are merged to obtain high voltage conversion ratio. The converter also has the capability of adding extra switched capacitor cells to attain very high voltage gain. To provide soft-switching condition in the wide range of output power, a new zero-voltage transition auxiliary circuit is employed which is responsible for soft switching of both phases and benefits from low conduction losses, the minimum number of semiconductor elements, and only one auxiliary gate-driver. These merits provide very high efficiency at both full-load and light loads. More importantly, no auxiliary magnetic components are utilized by taking advantage of the leakage inductance of coupled inductors for the resonant network. All semiconductor components operate under soft switching alleviating the reverse recovery problem and switching losses. Besides, the converter benefits from common ground between input and output which simplify voltage feedback. The experimental results of the interleaved converter prototype with 400-V output voltage at 400 W and 100 kHz switching frequency are provided. The full load efficiency of 98% was achieved and the power density was observed 1.9 W/Cm3

Soft‐switching non‐isolated high step‐up three‐level boost converter using single magnetic element

Abstract 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