Z-Network Plus Switched-Capacitor Boost DC-DC Converter

In this paper, a Z-network plus switched-capacitor based DC-DC boost converter (ZSCBC) is proposed. The integration of the Z-network with a 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 converter contains Z or impedance network, the operating duty ratio is less than 0.5, such as 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 converter are 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. The small-signal analysis is established, and a single-loop voltage-mode controller is designed. A 48-250-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.