Analysis of a new four quadrant switch mode DC-DC converter

Abstract

In this thesis, two separate switch mode converters with voltage lift circuits with two sources and complex gate pulse control has been investigated. To reduce the number of supplies to one and ease the control signals, differential connection of Luo forward and Luo reverse two quadrant choppers have been proposed and investigated. A new topology has emerged out of the research to provide four quadrant operation of a high frequency dc-dc converter having one supply source and easy gate pulse control. This new topology has been developed out of switching dc-dc converters with voltage lift circuits; its operational range is wide at high conversion efficiency, whereas, the present four quadrant switching dc-dc converters’ conversion efficiency decreases around the operation of a particular duty cycle. In previous work two separate switch mode dc-dc converters with voltage lift circuits, one working in two quadrant forward mode and the other working in two quadrant reverse mode have been switched by complex gate pulses to obtain the four quadrant dc-dc operation. Two sources are necessary for such circuit. Combining the two circuits to have single source topology would result in mal-operation due to overlapping switches. In this research differential connection of the load at the output of the two converters fed by same source has been investigated as per claimed of previous work. But the converter did not perform as four quadrant chopper because the reverse Luo converter does not work as it has been claimed. It is found in simulation that these two source converters do not operate as claimed and they cannot be combined in any way to operate in four quadrants as a single power conversion circuit. It was therefore, necessitated separate method to obtain SMPS based Buck-Boost single four quadrant DC-DC converter. The result is a single source topology switched by conventional ON/OFF duty cycle control as used in other high power chopper circuits. The combined topology has been analyzed and studied by spice simulation.