Resonant DC-DC converters with bridge rectifier filter circuits are regarded as a type of memristive circuit. However

existing models often neglect the harmonic components of circuit variables and equivalently treat the rectifier-filter circuit as a resistor. Therefore

it is difficult to accurately describe the transient and steady-state responses and memristive characteristics of the hybrid modulation resonant DC-DC converter

which poses challenges for the design of hybrid control strategies and the analysis of its dynamic behavior. Therefore

a memristive circuit dynamic model was proposed based on sigmoid functions for resonant DC-DC converters. Firstly

sigmoid functions were used to smooth the switching signals and establish an accurate model that can uniformly describe the switching networks under different modulation methods. Then

the rectifier bridge was represented equivalently by a controlled-source two-port network

and the memristor model of the rectifier filter circuit was derived. Finally

taking a series resonant DC-DC converter as an example

a memristive circuit dynamic model was established

and simulation and experimental verification were carried out. The results indicate that

compared to other models

the proposed model can describe the dynamic and static characteristics of the resonant DC-DC converter under hybrid modulation more accurately

laying the foundation for the application of continuous system theory to analyze and control.