A High Frequency Multiphase Modular Hybrid Transformerless DC/DC Converter for High-Voltage-Gain High-Current Applications

Abstract

In order to meet the demands of desirable efficiency, transformerless DC/DC equipment with great voltage step-down are inevitable needed. This research offers a unique type of high-frequency, high-voltage-gain DC/DC converter, which comprises a switched capacitor (SC) converter and a buck converter. Thanks to the transformation of a two-stage converter to a single-stage converter, it has a considerable ratio of step-down voltage transformation and a reasonable duty cycle. In addition, it can permit low voltage stress on the switches. The simple control method and easy driving circuit implementation makes it scalable for high-power-level devices. Low cost can be realized as fewer components are needed. Under all operational circumstances, total soft-charging and low equipment voltage stresses are accomplished. Compared to those classic high-voltage-gain converters, the proposed converter exhibits merits of higher efficiency, higher flexibility, lower ripples, and lower costs. A comprehensive analysis is carried out for the converter’s steady-state operations. With a 1 MHz switching frequency, a 900 W prototype of a 20-time converter is constructed, with a peak efficiency of 92.5%. Simulations and experiments verify the effectiveness of the theoretical investigation of the converter’s operation.