Analysis and Design of Coupled Inductor for Interleaved Multiphase Three-Level DC-DC Converters
The coupled inductor can reduce large inductor current ripple in the interleaved multiphase three-level converter, while retaining the benefits of interleaving. The design of the coupled inductor is different from conventional two-level converters. This paper analyzes the flux in the coupled inductors of interleaved multiphase three-level DC-DC converters. Based on flux analysis, a design procedure is introduced. A new structure for the coupled inductor is also proposed, in which two types of coupling are utilized, and only one integrated component is needed for the multiphase interleaved three-level converter. To utilize the tape-wound core (an amorphous, nano-crystalline material), a new structure is introduced, which simplifies the structure and reduces cost. A prototype using a nano-crystalline core that could reduce the inductor volume by over 40%, was built and experimentally verified.