Derivation, Design and Simulation of the Single-Ended Primary-Inductor Converter (SEPIC)
The purpose of the paper is to guide engineering students and ease their transition from the most basic DC-DC converter topologies to more advanced types. The buck, boost and buck-boost converters are the usual suspects in textbooks and engineering classes to introduce students to the basics of power electronics and switch mode power supplies. There is a gap of how detailed such second order DC-DC converters are described and the more advanced fourth order such as the Cuk, Zeta and Single-Ended Primary-Inductor Converter (SEPIC). This paper gives a detailed derivation of the equations governing the SEPIC. An example of sizing of components is presented for a range of input voltages and power levels. Finally the design is verified by a circuit simulation using LTSpice.