Design and Implementation of Non-Isolated Switched-Capacitor SEPIC Converters Using Duality Principle

Abstract

If the renewable source is connected to utility, a current source (CS) is required. The conventional converter design is based on a voltage source (VS). A voltage source has a dual relationship with a source, so this paper takes the dual principle as the basis and uses the dual approach to propose converters based on the current source. The duality theory can be used to convert the switched inductor (SI) structure into a switched capacitor (SC) structure, that is convert a step-up voltage topology into a step-up current topology.In this paper, taking the Single Ended Primary Inductive Converter (SEPIC) converter as an example, the conventional voltage source SEPIC converter is converted into a current source SEPIC converter, and then the capacitor is replaced by a step-down switched capacitor structure to form a current source switched capacitor (CSSC) converter. The input current of the proposed topology is Iin=1 A~5 A, and the switching frequency is 100 kHz. Maximum output current Io is 15 A, and the output power is 1125 W. The efficiency can be at least 90.62 %.