Matrix Inductor With DC-Bias Effect Reduction Capability for GaN-Based DC-DC Boost Converter

In this brief, a 400-W Gallium Nitride device based DC-DC boost converter with a four phase matrix inductor is proposed. It is well-known that there is a significant influence of the DC bias on inductor core losses and the simplest solution is to employ multiphase structures. However, the size of the converter will also increase as the number of phases increases. Therefore, in order to achieve both high efficiency and high power density, a matrix inductor is proposed for four phases boost converter. The proposed matrix inductor retains the flux sharing advantages of conventional inductors with E-cores and thus greatly increases the power density and utilization rate, by integrating the inductors through flux cancellation. Therefore, both the size and the core loss are reduced when compared with four conventional inductors. Moreover, since the four phases are operated in parallel, the phase error, which is a critical problem in the interleaved structure, may not affect the proposed converter, removing the current balance issue. Critical operation mode is utilized to achieve zero-voltage switching (ZVS) for all switches. Finally, the proposed four phase DC-DC boost converter and matrix inductor is built and tested to verify its feasibility. The peak and CEC efficiency is tested to be 99.3% and 99.1%, respectively.