Leakage Inductance Estimation of Toroidal Common-mode Choke from Perspective of Analogy between Reluctances and Capacitances

Abstract

To reduce the volume and weight of differential-mode (DM) inductors, the leakage inductance of a toroidal common-mode (CM) choke is ofen used as partial DM inductance. However, the accurate prediction of the leakage inductance of CM chokes through an analytical model is difficult, making the determination of remaining DM inductance difficult. This paper proposes a modeling method with the analogy between reluctances (or magnetic fields) and capacitances (or capacitive fields). The proposed method is verified by the leakage inductance comparison between the proposed model and simulation results for two CM cores with different turns numbers and wire gauges, and it demonstrated the proposed model can achieve the errors within 15% compared with simulation results for all cases.