Near-Field Coupling Mitigation of the Noise from High Voltage DC-Link Decoupling Capacitors in Voltage Source Converters

With the adoption of wide-bandgap (WBG) devices, high-voltage DC-link decoupling capacitors in high-density bidirectional converters (HDBCs) are increasingly prone to generating near-field (NF) coupling noise, which can affect surrounding circuits. This NF coupling can negatively impact the stable operation of voltage source converters, leading to issues such as mistriggering of switching devices and electromagnetic interference (EMI) in low-voltage systems. This paper investigates strategies to mitigate NF coupling noise from high-voltage DC-link decoupling capacitors (DCAPs) through a comprehensive workflow combining finite element analysis (FEA) and circuit simulation tools. The study provides design guidelines for optimizing DCAP placement to minimize NF radiation while achieving effective EMI suppression. This research aims to bridge the gap between the application of DCAPs for EMI differential mode (DM) noise control and NF coupling management in highly integrated power converter designs.