Research on Harmonic Noise Characteristics of Train Four-Quadrant Converter Using SiC Devices

High frequency devices represented by SiC have the advantages of low switching loss, high switching frequency, and high junction temperature. Consequently, SiC have emerged as the dominant direction for the development of the new generation of traction converter technology. This study specifically examines the harmonic noise characteristics of the four-quadrant converter (4QC), which utilizes SiC devices in trains. Firstly, the influential factors affecting the harmonic characteristics on the grid side of the SiC 4QC are investigated through theoretical derivation. Secondly, the common-mode (CM) conducted interference coupling path of the 4QC is analyzed, and an equivalent circuit for the CM electromagnetic interference (EMI) is constructed. By studying the spectrum of the CM voltage source, the factors influencing the CM EMI in the SiC 4QC are analyzed. Then, an optimal selection method for selecting the switching frequency of the SiC 4QC is proposed, taking into account both the harmonic characteristics on the grid side and the CM EMI characteristics. Finally, a low-power experimental platform is established, and the research content is experimentally verified.