Parasitic Effects of Grounding Paths on Common-Mode EMI Filter's Performance in Power Electronics Systems

TLDR

High‑frequency common‑mode EMI noise is hard to suppress, and grounding‑path parasitics significantly degrade filter performance. The study investigates how grounding‑path parasitics affect an EMI filter’s performance in a motor‑drive system. It examines mutual inductance between two grounding paths and validates the analysis with simulations and experiments. Guidelines for grounding CM EMI filters are derived.

Abstract

High-frequency common-mode (CM) electromagnetic-interference (EMI) noise is difficult to suppress in electronics systems. EMI filters are used to suppress CM noise, but their performance is greatly affected by the parasitic effects of the grounding paths. In this paper, the parasitic effects of the grounding paths on an EMI filter's performance are investigated in a motor-drive system. The effects of the mutual inductance between two grounding paths are explored. Guidelines for the grounding of CM EMI filters are derived. Simulations and experiments are finally carried out to verify the theoretical analysis.