Study on Influence of Leakage Flux Dependence on Winding Position of Common-mode Choke Coil Using Toroidal Core

An equivalent circuit model of the coils is required to study the performance of the choke. This model must represent both the normal and common modes and the electromagnetic couplings between the windings. In this research, the leakage flux dependence on the winding position were evaluated by using a single-phase common-mode choke coil of nanocrystalline alloy and Mn-Zn cores. As a result, the leakage inductance increased up to twice independent of the frequency with opposing wind-ings position. It was also found from the simulation that the change in leakage inductance is due to the change in leakage flux, which is determined by the size of the core.