Improved Quasi-Z-Source High Step-Up DC-DC Converter Based on Voltage-Doubler Topology.

Abstract

The step-up DC-DC converter is widely used for applications such as IoT sensor nodes, energy harvesting, and photovoltaic (PV) systems. In this article, a new topological quasi-Z-source (QZ) high step-up DC-DC converter for the PV system is proposed. The topology of this converter is based on the voltage-doubler circuits. Compared with a conventional quasi-Z-source DC-DC converter, the proposed converter features low voltage ripple at the output, the use of a common ground switch, and low stress on circuit components. The new topology, named a low-side-drive quasi-Z-source boost converter (LQZC), consists of a flying capacitor (CF), the QZ network, two diodes, and a N-channel MOS switch. A 60 W laboratory prototype DC-DC converter achieved 94.9% power efficiency.