Single‐Switch High Step‐Up Quasi‐Z‐Source DC‐DC Converter With Low Switch Voltage Stress

ABSTRACT High step‐up converters are commonly utilized to manage voltage level between the DC‐bus and low voltage input. The properties such as high‐voltage gain, continuous input current and low switch voltage stress are important for proper performance. The method of coupled inductors is applied to the boost topology in the recent papers to extend voltage gain. Although this method can increase voltage gain, the discontinuous input current is the main drawback. The switched capacitor is another scheme used to increase the voltage gain which usually led the converters to suffer from the high component count. In this paper, a high step‐up converter is presented by integration of switched capacitor and coupled inductors with quasi‐z‐source structure to maintain the continuous input current. A switched capacitor along with a pair of coupled inductors are utilized to enhance voltage gain and switch voltage stress. Also, zero current switching for switch at turn‐on and for all diodes at turn‐off reduce reverse recovery problem. A passive clamp circuit is utilized to absorb the leakage inductance energy, and improve voltage gain by placing the clamp capacitor in the charge path of the switched capacitor. Also, the main properties of quasi‐z‐source converter such as common ground between the output and input sides along with continuous input current is maintained. Additionally, these features are realized by proper component count in comparison with other related topologies based on quasi‐z‐source topology. The experimental results are extracted by a prototype circuit implemented at 300 W and 100 kHz to confirm the theoretical results and the proposal converter operation.