A Load-variable Noise-source Equivalent Circuit Model for DC-DC Converter Considering Cubic Spline Interpolaion

The black-box models have been proposed to predict electromagnetic interference from power electronic devices owing to their modeling simplicity. During the modeling process, the load value is normally kept fixed so that the device can perform almost linearly since the load variation changes the switching conditions of the power supply and the nonlinear performance occurs. This work examines the accuracy of predicted interference voltages by using a black-box model, a measurement-based 2-port equivalent circuit model for a DC-DC buck converter considering the load effect. Then a numerical fitting tool, cubic spline interpolation is applied to identify the parameters noise-source equivalent circuit without measuring at the same load value. As a result, it is found that the input port noise source predicted by cubic spline interpolation has a good agreement with parameter identification result.