A Family of Z-source and Quasi-Z-source DC-DC Converters

This paper presents a family of four-quadrant dc-dc converters with minimal number of switches and passive devices. These converters employ a Z-source or a quasi-Z-source network with two active switches to provide four quadrant operation which means bipolar output voltage and bidirectional current operation. Bipolar output operation can also be realized by using one active switch and a diode. They also own buck and boost characteristics when the duty cycle is changed from zero to one. At 0.5 duty cycle, these converters can output either zero or infinity voltage. Experimental results are given to demonstrate the validity and features of these circuits.