PROJECT TITLE :

A Family of Isolated Buck-Boost Converters Based on Semiactive Rectifiers for High-Output Voltage Applications

ABSTRACT:

A scientific technique for developing isolated buck-boost (IBB) converters is proposed in this paper, and single-stage power conversion, soft-switching operation, and high-efficiency performance can be achieved with the proposed family of converters. On the idea of a nonisolated 2-switch buck-boost converter, the proposed IBB converters are generated by replacing the dc buck-cell and boost-cell within the non-IBB converter with the ac buck-cell and boost-cell, respectively. Furthermore, a family of semiactive rectifiers (SARs) is proposed to serve as the secondary rectification circuit for the IBB converters, that helps to increase the converter voltage gain and cut back the voltage stresses on the devices in the rectification circuit. Hence, the potency is improved by employing a transformer with a smaller turns ratio and reduced parasitic parameters, by using low-voltage rating MOSFETs and diodes with better switching and conduction performances. A full-bridge IBB converter is proposed and analyzed well for instance. The section-shift modulation strategy is applied to the complete-bridge IBB converter to realize IBB conversion. Moreover, soft-switching performance of all active switches and diodes will be achieved over a good load and voltage vary by the proposed converter and control strategy. A 380-V-output prototype is fabricated to verify the effectiveness of the proposed family of IBB converters, the SARs, and also the control strategies.