Detailed characterization of coupled inductors in interleaved converters regarding the demand for additional filtering

To obtain highest efficiency in electric vehicles and to increase the lifetime of the traction battery, a battery buffer system which consists of a DC/DC converter and electric double layer capacitors can be implemented. To achieve low volume and high efficiency, multiphase interleaved converters are used for the DC/DC converters. The inductors represent a main part concerning the converter volume. Coupled inductors can reduce the volume and increase the efficiency. In case of high coupling, additional filtering is required to reduce the current ripple. There are different options to realize the filtering. In this paper, a characterisation for coupled inductors in a three-phase interleaved converter is presented. The different filter types are introduced and their influence to the system characteristics is analyzed and discussed.