Measurement of AC Loss Characteristics of HTS Sample Coils Under the Conditions Assumed for use in Power Electronics Devices

Abstract

To examine the applicability of superconducting technology to fields of industrial applications such as linear conveyor, transfer, and transport systems, we investigated the AC loss characteristics of HTS sample coils under conditions assumed for use in power electronics devices. Since inverters are used in the drive circuit of power electronics devices in a linear transfer system and so on, the drive current contains harmonic components, and then it is expected that the AC losses increase. In this study, we measured the AC loss characteristics of the HTS sample coil by the liquid nitrogen boil-off method under various conditions in which the amplitude and frequency of the harmonic current were changed. The HTS sample coils were wound by a Bi-2223 tape. The outer diameter of the sample coil is about 60 mm, and the height is about 25 mm. As the result of the measurement, the AC loss increased in proportion to the square of the harmonic current amplitude and increased in proportion to the 1.5th power of the harmonic frequency. Based on the measured results, the increase of AC losses due to the harmonic current component was discussed.