SWITCHED-CAPACITOR/SWITCHED-INDUCTOR STRUCTURES FOR GETTING TRANSFORMERLESS BIDIRECTIONAL DC–DC PWM CONVERTERS: STEADY STATE AND DYNAMICS

This paper is devoted to expanding sphere of application of the universal Switched-Capacitor/ Switched-Inductor Structures by replacing the diodes with MOSFETs. These structures allow to build a large family of bidirectional converters with an increased/decreased voltage ratio depending on the operating mode. These structures are based on the three diode blocks proposed for decrease the voltage and three diode blocks for increase it. The use of MOSFETs allow to save all the properties of these structures in the diode mode, but also to obtain new possibilities when the transistors operate themselves. At the same time, the step-down structures become increasing, and, conversely, the step-up structures become decreasing. The paper describes the basic structures, describes the Boost / Buck and Buck-Boost bidirectional converters, and shows opportunity of their use in bidirectional Cuk, Sepic and Zeta converters. To analyze the dynamics of such converters having a rather complicated structure, a methodology for replacing them with an equivalent circuit of a conventional converter of the same type, the dynamic characteristics of which are well known, is proposed. An analysis of their work and the results of the experiment are given, which confirm the correctness of the conclusions.