Analysis of CM volt-second Influence on CM Inductor Saturation and design for input EMI filters in Three Phase DC-Fed Motor Drive

摘要

Common mode (CM) choke saturation is a practicalproblem in common-mode filter applications. It’s generallybelieved that the leakage inductance of common-mode chokesmakes the core saturated. This paper analyzes two newmechanisms for common-mode choke saturation due tocommon-mode voltage, and these mechanisms are verified inexperiment. Common-mode choke saturation is particularlyimportant for motor drive systems, which have a high commonmodevoltage and comparably higher stray groundingcapacitance. A model is established to describe the relationshipbetween the common-mode voltage and the volume of thecommon-mode magnetic components. According to the analysis,LISNs (line impedance stabilization networks) play animportant role in the design of CM magnetic components.