Behavior modeling of magnetizing currents in switch-mode DC-DC converters

This paper describes a new technique to model the behavior of the magnetizing current in a transformer-coupled switch-mode DC-DC converter. The new technique uses a virtual magnetizing winding, together with a virtual magnetizing current source, to account for the effect of the magnetizing inductance on the switching operation of the transformer. By including the effect of the magnetizing current, the behavior model of a switch-mode converter can be made more complete. The model developed is particularly useful for the analysis and low-frequency behavior simulation of complex converters such as actively-clamped converters, where the magnetizing current significantly affects the characteristics of the converter.