Study on Dynamic Accurate Modelling and Nonlinear Phenomena of A Push-Pull Soft Switched Converter

In soft switched converters, the autonomous characteristic and complex boundary conditions bring forth complex dynamic behaviours different from those in hard switched converters characterized by fixed switched period. These characteristics also make present accurate modelling methods such as stroboscopic mapping modelling designed for fixed switching can´t apply to soft switched systems. This paper proposes a numeric accurate modelling method for soft switched circuits according to those special characteristics. The application for a push pull soft switched converter exemplifies this accurate modelling method. In simulation, a frequency jump phenomena is observed. With the aid of impedance analysis, this paper discovers that the nonlinear phenomena root in the occurrence of multi zero phase angle frequencies with load parameter variation. At last, experiment observations verify these phenomena and this modelling method