EMI Prediction in Power Converters Through CST Field-Circuit Co-Simulation

The high-frequency switching in power converters induces complex electromagnetic interference (EMI), significantly degrading the operational reliability of both the converters and nearby electronic systems. Traditional EMC design methodologies predominantly employ post-hoc remedial approaches. The absence of electromagnetic compatibility (EMC) considerations during initial design phases frequently results in substantial postproduction modifications, incurring significant time and cost penalties. To address these limitations, this paper proposes a fieldcircuit co-simulation approach using CST software for early-stage prediction of converter EMI noise. A comprehensive EMI simulation framework for power electronic converters is developed through detailed modeling of critical components, including inductors, capacitors, transformers, switching devices, diodes, and antennas, enabling precise EMI prediction. Finally, the accuracy of the proposed field-circuit co-simulation EMI modeling approach was validated through comparative analysis between simulation and experimental results, including both conducted and radiated noise measurements, for a cascaded Boost PFC+LLC+Buck converter system. This approach not only enables precise prediction of electromagnetic behavior of power electronic converters in practical operating conditions, but also facilitates EMI-forward design during product development. Additionally, it provides an efficient and convenient solution for post-design EMI mitigation.