On the Simulation of Conducted Emission of a Flyback Converter using LTSpice

On the example of a commercially available evaluation board of a flyback converter, as used for auxiliary low-voltage supply from high-voltage battery in automotive power trains, this paper demonstrates the impact of the main circuit components on conducted emissions (CE) according CISPR25 up to 30 MHz. The analysis is based on a simplified LTSpice simulation model. Simulated differential-and common-mode emission spectra are compared to measurement. Different modeling approaches for critical circuit components are investigated to outline a least-effort approach for CE simulation.