A Novel Measurement Method for DC Superimposition Characteristics of Three-Phase Coupled Inductors with Powder Cores

the objective of this research is to build the measurement method of DC superimposition of multiphase coupled inductors with powder cores. From a perspective of magnetic material, powder cores are usually applied to inductor core in high current applications such as E-mobility due to their attractive features. In addition, multiphase DC/DC converters with coupled inductors can effectively downsize passive components that occupy significant space in power converters. However, when applying coupled inductor with powder cores under the dc current superimposed condition, self-inductance and mutual inductance values of coupled inductors are varied depending on dc current values. Furthermore, measurement methods of the dc superimposition characteristics of multiphase coupled inductor have not been discussed in the relevant literature. Therefore, this paper proposes two measurement methods for DC superimposition characteristics of three-phase coupled inductors with powder cores used in three-phase DC-DC converters. The first method is for three-phase coupled inductors with an asymmetric magnetic core structure, and the values of each self-inductance and mutual inductance can be measured separately. The second method is a simplified measurement method limited to multiphase coupled inductors with symmetric magnetic core structures. DC superimposition characteristics of coupled inductors can be measured with a smaller number of measurements than the first method, and it can be extended to N phase coupled inductors. The verification of the two methods has been evaluated through simulation and experiment.