Modeling of power converters employing the WCR-4SSC

Abstract

This work presents a generalized modeling methodology for the 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). The core of the methodology relies on the state-space averaging (SSA) technique. A key contribution of this research is the simplification of the converter’s six distinct switching stages into an equivalent two-stage model. This simplified model is governed by an equivalent duty cycle (d∗) that is dependent on the converter’s specific operating region (R1, R2, or R3). A step-by-step procedure for deriving the averaged model and its subsequent linearization is established and applied in detail to the WCR-4SSC Cuk converter as a representative example, resulting in the derivation of its complete set of small-signal transfer functions. To validate the proposed methodology, the derived analytical model (implemented in MATLAB) is compared against detailed circuit simulations (PSIM). The results demonstrate excellent agreement in both the frequency domain (Bode plots) and the time domain (transient responses). This confirms the model’s accuracy across different operating points and validates the methodology as a robust and generalized foundation for the analysis and control design of all converters in the WCR-4SSC family.