Accurate Time-Domain Prediction for Performance Tuning of Active EMI Filters Using CE Source Model for a DAB Converter With SSM

This article proposes a time-domain simulation approach for common-mode (CM) active electromagnetic interference (EMI) filters (AEFs) to enable accurate performance prediction and facilitate robust tuning against performance reduction. Reliable performance prediction is required for effective noise attenuation and practical tuning of EMI filters under the target conducted emission (CE) conditions. Conventional EMI filter analysis is typically based on small-signal frequency-domain simulation. However, for AEFs, this small-signal analysis may not account for the nonlinear behavior of active components, often leading to discrepancies between predicted and measured CE data. To address this limitation, a time-domain simulation approach is adopted. The simulation incorporates the time-domain in-circuit noise source model of a 3.3-kW dual active bridge converter extracted under an operating condition using the two-probe method. In addition, the 3D model of the physical layout in the EMI filter configuration is employed to reduce discrepancies arising from the actual measurement environment. The accuracy of the time-domain performance prediction is verified through comparison with actual CE measurement data. Based on the validated simulation, the nonlinear behavior of active components is analyzed, and performance tuning cases for maintaining linear operation are presented. Furthermore, comparative analyses according to the spread spectrum modulation are conducted, confirming the accuracy and robustness of the proposed time-domain method.