Analysis and Design of Fourth-order Quasi-Z-Source Equivalent DC-DC Boost Converter

A fourth-order quasi-Z-source equivalent DC-DC boost converter (FOEBC) exhibiting the voltage gain conversion ratio identical to Z-source dc-dc boost converter (ZSC) is proposed in this paper. It provides voltage gain identical to ZSC but with smooth source current waveform and thus leads to reduced EMI. On the basis of steady-state analysis, the principle of operation, exchange of energy among various inductive and capacitive elements is explained. Subsequently, design guidelines for inductors and capacitors is established. To highlight the controller design issues, small-signal analysis of the proposed converter is presented. A voltage-mode controller is designed to demonstrate its feasibility both in simulation and experiments. A 42 V to 100 V, 50 W laboratory prototype verifies the converter regulation capability against source and load disturbances. The comparison of proposed converters with other conventional power converters is also described.