Full order dynamic model of SEPIC converter

In this paper a full order dynamic model of the non-isolated and isolated DC-DC SEPIC (single ended primary inductance converter) is presented. The switches (transistor and diode) are substituted by PWM averaged switch model equivalent circuit. The SEPIC converter is used in the cases when the wide range of input voltages has been required. There are two inductors and two capacitors inside the converter circuit. Due to this, its mathematical model is of the fourth order differential equations system. Duty-cycle and transformer turn ratio have impact on the converter dynamics. The derived dynamic model was verified by simulation toolbox Sim PowerSystems.