The Methodology of Constructing the Quadratic Converters

This article provides a systematic method to construct types of quadratic converters. A three-terminal, four-element switching cell, consisting of one diode, one switch, one capacitor, and one inductor, is inserted into a separated conventional switching cell to create the quadratic converter. Detailed steps of the proposed method are described. Almost all the known nonisolated quadratic converters with two inductors, two capacitors, two power switches, and two diodes (or one power switch and three diodes) can be redeveloped by this method, but also many new topologies can be proposed. For example, the three-terminal, four-element switching cells can be inserted into SEPIC, CUK, and ZETA converters in different ways to derive different types of quadratic topologies. Furthermore, the proposed method can be extended to generate cubic or $n$ th power converters. Many of these quadratic converters are compared in terms of their dc gain, number of switches and diodes, voltage stress on the switches, character of input current, output polarity, and so on. The selection procedure to determine which quadratic converter might be used for different applications is presented. Finally, to demonstrate the generality of the approach, a new type of quadratic converter is derived and evaluated in both simulation and experiment.