Evaluation of a High-Frequency Reactor with a New Wire Guide for a Toroidal Core

This paper proposes a new high-frequency reactor with a wire guide for small-size toroidal core. In theory, reactor size can be reduced in proportion to switching frequency. However, practically, as the switching frequency is increased, the reactor is affected by the parasitic capacitance existing between the windings and between the winding and the core, and the inductance characteristic of the reactor is deteriorated. As a result, there is a limit to increase the switching frequency. This paper proposes two kinds of wire guides with two-layer winding and three-layer winding to reduce the parasitic capacitance. The effects of the wire arrangement and the material of the guide are also evaluated. With the proposed guides, the parasitic capacitance decreases by 0.73 times and 0.66 times compared with the conventional reactor. Moreover, the linear regions of the impedance which can be regarded as a pure inductance are enlarged.