Simplified Small-Signal Modeling Method for Non-Isolated High Step-Up Converters

Abstract

This work presents a generalized small-signal modeling methodology for a family of DC–DC converters based on the four-state switching cell with a wide conversion range (WCR-4SSC) operating in continuous conduction mode (CCM). Although the proposed approach is derived from the well-established state-space averaging (SSA) technique, it simplifies the modeling process by representing the six operating stages as an equivalent two-stage solution. The resulting averaged model is defined in terms of an equivalent duty cycle, whose expression depends on the converter operating region (R₁, R₂, or R₃), which is determined by the rated duty cycle. A step-by-step procedure for obtaining the averaged model and its subsequent linearization is presented and applied to a DC–DC Ćuk converter based on the WCR-4SSC, yielding several transfer functions of interest. To validate the proposed methodology, the analytical model is compared with the switched converter. The results show good agreement in both the frequency and time domains, confirming the accuracy of the proposed solution.