Calculation of DC-DC SEPIC converter by averaging method

This paper illustrates the application of averaging method based on Lagrange theorems for analysis and calculation of SEPIC converter operating in continuous conduction mode of reactive storage elements. It is shown that this method simplifies the calculation of converter by reducing the number of calculations and avoiding cumbersome intermediate transformations. A mathematical model has been developed that reflects the relationship between the parameters of SEPIC converter and the convenient analytical relationships for calculating the constant and pulsating components of converter processes are obtained. Based on them, expressions for calculating the boundaries of continuous conduction modes of reactive storage elements, as well as the maximum currents and voltages in the switching elements and other parameters of SEPIC converter are developed. The obtained analytical relations allow to apply the methods of mathematical analysis of quantitative and qualitative characteristics of processes, which helps to increase the efficiency of converter calculation at the stage of its design.