New EMI Model With the Same Input Impedances as Converter

Among the already developed electromagnetic interference (EMI) models, there are the three-terminal models based on the estimation of impedances. These models are very interesting. Compared to the other models, they have the advantage of predicting conducted interference generated by the filtered electronic devices. In this paper, in order to contribute to this type of modeling, a new EMI model for power converters is proposed. This model has the same input impedances as the converter, which allows predicting filtered and unfiltered conducted interferences in a more accurate manner. It is based on estimating input impedances of the actual converter, using a new method developed analytically. This method requires only off-line measurements, making the model easy to identify and can be applied even to high-power converters. Experimental illustrations are also included to verify the validity of the proposed model. Comparison between measured and predicted results with and without EMI filter shows that the model provides adequate prediction of the EMI feature for power-switching converters.