In　this　paper,　the　magnetic　density　distribution　of　three-phase　common-mode　inductors　under　different　magnetic　bias　is　obtained　by　finite　element　simulation　of　electromagnetic　field,　and　the　segmental　reluctance　model　of　the　vertical　core　is　established.　The　dynamic　permeability　distribution　of　three-phase　common-mode　choke　is　obtained　by　combining　the　characteristic　curve　of　the　material,　so　as　to　calculate　the　dynamic　inductance　under　different　magnetic　bias.　The　establishment　of　the　model　provides　design　guidance　for　the　optimization　design　of　the　common　mode　choke,　reducing　the　volume　and　improving　the　noise　suppression　ability.　The　simulation　results　agree　well　with　the　experimental　results,　which　shows　that　the　proposed　calculation　method　for　the　dynamic　inductance　of　the　common　mode　choke　is　effective.　　©　2024　IEEE.