Variable Coupling Coefficient Integrated Inductor for Hybrid Energy Source Systems

Abstract

This paper proposes an innovative integrated inductor technology for hybrid energy source systems (HESS). The proposed inductor uses novel variable coupling coefficient integrated inductor (VCCII) technology to integrate two inductors that are required for a dual boost converter for HESS. VCCII has an integrated structure of two inductors, and enables to control the coupling coefficient between the two inductors depends on the power distribution ratio of two power sources. In a low-power operation, the coupling coefficient between the two inductors is structurally zero, which enables the VCCII technology to control each output of energy sources independently without interference. In high-power operation, the coupling coefficient of the two windings increases by utilizing the non-linear characteristics of a magnetic core. These cou-pling effects peak shaving of the inductor current, which contributes to loss reduction and increase the maximum power capability. A prototype result verifies a 50 % increase of peak power density and a 15% increase of maximum power capability under 20 V / 100 A and 25 V / 40 A inputs and 42 V output HESS. Additionally, the result gives 1.9% efficiency improvement in a double boost converter circuit operating in 100-kHz switching, 810 W output.