DC-DC converters, reducing or decreasing the input voltage at the output, are commonly used in many power electronics application. Generally, all types of converter are derived from Buck or Boost converter topology. Similarly, Single-Ended Primary-Inductor Converter (SEPIC) is composed from buck converter topology, but may reduce or decrease the input voltage. In this paper, SEPIC converter is analyzed and two control methods, PI and One Cycle Control (OCC), have been applied to set the output voltage at desired voltage level with 500 W output power and 20 kHz switching frequency. In order to get better result with OCC, the generalized control structure has been changed and different types of OCC method are presented. The simulation results have been obtained by using Simulink/MATLAB and compared with each other. The results include the dynamic response of the suggested control methods with variation of reference, power at output and input voltages. And, the proposed OCC method has better results from the point of load and reference variation. For input voltage variation PI control method is superior.