A Closed Loop Phase Shift Control of Isolated Buck Boost Converters for High Voltage Applications

Abstract

A novel isolated buck-boost converter with high gain output voltage controlled by a closed loop phase shift control is proposed here. The phase shift control dynamically changes the converter output voltage with reduced ripple content. Here, a family of semi active rectifiers (SARs) is introduced to act as a secondary rectification circuit, to reduce the voltage stresses on the devices and improves the voltage gain thereby achieving the high conversion efficiency. A transformer with smaller turn’s ratio, MOSFETs and diodes with better switching and conduction performances is employed to achieve the high conversion efficiency. As an example, an isolated full bridge converter is analyzed here. To achieve the IBB conversion phase shift modulation technique to this converter is applied. With this converter the soft switching operation of switches and diodes over a wide voltage range can be achieved. The converter design and modeling is done in MATLAB software. The experimental results and graphs of the proposed converter are represented.