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Research

Click here for a list of graduation and master's thesis titles.

Research

Here are some of the studies.

High Energy Density of Electric Equipment by Application of Superconductivity

Superconducting wires are used in high magnetic field generation coils (superconducting coils) for MRI and NMR because they have zero resistance when direct current is applied. However, the superconducting coils that have been commercialized so far are coils wound with metallic superconducting wires called low-temperature superconducting wires that use liquid helium as a refrigerant. For this reason, it is necessary to develop a helium-free conduction-cooled high-temperature superconducting coil to meet the worldwide demand for MRI applications. Therefore, we are designing and developing high field coils. Since the current density of superconducting wires is much higher than that of copper wire, its application to power equipment is expected to lead to miniaturization, higher energy density, and higher output. However, since AC loss occurs when the wire is energized, the loss at very low temperatures causes deterioration inefficiency, and coupled with the penalty of needing cooling, the wire has not yet been put to practical use. Therefore, we are developing an accurate measuring device for the AC loss of superconducting wires, and we are researching the evaluation and reduction of AC loss. Furthermore, we use numerical analysis to research next-generation high energy density power devices that skillfully incorporate superconducting technologies.

Non-contact power transfer

In recent years, wireless power transfer technology has begun to be used in the power charging systems of smartphones and electric vehicles. Although non-contact power transfer systems have the advantage of being able to transmit electric power even in spatially distant locations, there are still some issues to be solved, such as higher efficiency and smaller size. However, there are still some problems to be solved, such as high efficiency and small size. We are studying the shape of the coil for high-capacity power transmission.

Magnetic materials

Ferrite, which has excellent properties at high frequencies, is widely used in switching power supplies and other applications. However, there are still some aspects of ferrite's fundamental loss characteristics that have not been clarified. Our aim is to contribute to improving the performance of devices that use ferrite, such as downsizing and low power consumption, by quantitatively clarifying the loss characteristics.

DC-DC converter

With the recent increase in the introduction of direct current devices such as solar power generation, DC power networks, and bi-directional DC/DC converters that can transmit power in both directions are attracting more and more attention. Among them, current resonant converters have the advantage of high efficiency, but there are some conditions that make them impossible to operate. We are researching the improvement of converter performance such as enlargement of operable conditions, improvement of efficiency, and miniaturization.

Titles of graduation and master's theses

2021Graduation Thesis

2021Master's Thesis