ABSTRACT

In this project, two Z-network plus switched-capacitor based DC-DC boost converters (ZSCBC) are proposed. The integration of the Z-network with switched-capacitor is responsible for yielding a high voltage gain and that too at lower duty ratios compared to the conventional quasi Z-source DC-DC converter (QZSC). Since the proposed converters contains Z or impedance-network, the operating duty ratio is less than 0.5 like in QZSC and retains its advantages such as common ground and low voltage stress on Z-network capacitors. Unlike QZSC, the switch and all the diode voltage stresses in the proposed converters is low even at high voltage gains. A detailed steady state analysis is presented to identify the salient features of the proposed Z- network based boost converter and thereafter compared with other Z-source based configurations. Small-signal analysis is established and a single-loop voltage mode controller is designed. A 48 to 250 V, 130 W prototype is built to demonstrate the effectiveness of the ZSCBC. The steady-state and closed-loop response measurements validate the theoretical studies.