Advanced EMI Prediction in Three-Phase Motor Drive Systems: A Unified Approach for CM and DM Noise Modeling

This paper addresses the challenge of Electromagnetic Interference (EMI) modeling and prediction in three-phase inverters, highlighting the importance of accurate modeling to identify system parasitics and noise sources for effective EMI mitigation in AC motor drives. Traditional Frequency-Domain (FD) models have often treated Common Mode (CM) and Differential Mode (DM) noise separately, complicating total noise prediction and mitigation. This has involved either separate models for CM and DM noise, or attempts at combining these models which struggled with accurately representing the system symmetry, noise paths and sources along with the relevant parasitics.We propose a unified modeling approach that integrates CM and DM noise predictions on the inverter DC side within a single framework, aiming to simplify and enhance the accuracy of EMI noise modeling. This approach facilitates a comprehensive understanding of EMI behaviors, particularly on the DC side of three-phase inverters, and addresses the limitations of previous methods by avoiding introduced impedance imbalances and asymmetries or extensive component-wise Time-Domain (TD) modeling. By comparing our model’s predictions with empirical system measurements, we validate its effectiveness and reliability. Our work sets a new benchmark for predictive modeling, offering significant insights for system design, prototyping, and EMI mitigation in modern motor drive systems, ensuring improved performance, reliability, and EMC compliance.