Investigating the grounding of EMI filters in power electronics systems

It is difficult to suppress high-frequency common mode (CM) EMI noise in power electronics systems. CM filters are used to suppress CM noise, but their performance is greatly affected by the effectiveness of their grounding. In this paper, the grounding issues for EMI filters, such as the mutual inductance between two grounding paths are discussed. The paper then discusses and analyzes several grounding approaches. Based on this investigation, guidelines for efficient grounding are proposed. Experiments are then carried out to verify the theoretical analysis.