Design of “EIE” Shape Coupling Inductors and Its Application in Interleaved LLC Resonant Converter

In order to solve the problems of large number of magnetic components and unequal current in interleaved LLC resonant converter, inverse coupling of two-phase resonant inductors is proposed. On the basis of traditional EE” and EI” shape coupling inductors, the “EIE” shape coupling inductors are proposed, which solve the problems of traditional coupling inductors, such as air gap is too concentrated, distribution of magnetic pressure is not uniform, and coupling coefficient is low. In order to verify the current sharing scheme, separate inductors and coupling inductor are made respectively. The experimental prototype of an interleaved LLC resonant converter with 48V input and 1kW/400V output is built. The comparison experiment shows that the current sharing is basically realized when the coupling coefficient is selected at certain value.