A Thorough Analysis for the Impact of the Coupling Coefficient on the Behavior of the Coupled Inductor High Step-Up Converters

In this article, the impact of the coupling coefficient K on the static continuous conduction mode (CCM) dc voltage gain of the basic passive clamp coupled inductor boost converter is investigated. First, an analytical method for the extraction of the accurate static CCM dc voltage gain and all the necessary formulas for the comprehensively description of the operating behavior of the converter is presented. Next, a comparison between the previous methods from which the proposed approximate static CCM dc voltage gain formulas are derived and the proposed one takes place. Subsequently, from the analysis and the plots, it appears that the coupling coefficient creates a dependence on the operation by the output current of the converter, which is more intense as the coupling coefficient decreases. Furthermore, it is concluded that the decrease in the dc voltage gain depends not only on the coupling coefficient K , but also on the turns ratio of the coupled magnetic component. Finally, experimental results based on a 250-W laboratory prototype with four different magnetic components are presented for the evaluation of the theoretical analysis.