Electricity and Electronics applications

Energy

## Development of HTS Motors Cooled by Liquid Nitrogen

Keyword: Conception of a new construction of HTS motors, Existence of an active corporation for practical application, Concentration of corporations with high techniques

Organizations Involved

○ Hidehiko Sugimoto, Professor, Graduate School of Engineering, University of Fukui

○ Ishikawajima-Harima Heavy Industries Co., Ltd.

O Taiyo Nippon Sanso Co. O Nakashima Propeller Co., Ltd.

O Hitachi, Ltd.

Sumitomo Electric Industries, Ltd.

Niigata Power Systems Co., Ltd.

Fuji Electric Systems Co., Ltd.

Prof. Sugimoto

【Abstract】Over 20 years are passed from the discovery of the high temperature superconductors (HTS), and the applications are greatly expected to make the electric machine smaller, lighter and more efficient. Under such situation, we devised the liquid nitrogen cooling HTS motor of new structure. And the trial motor was developed by collaborative research. Afterwards, the techniques were transferred to corporations. For practical use, the liquid nitrogen cooling HTS motor with 400kW output at 250rpm for ship propulsion is being developed at present. The motor has been developed in the cooperation since the initial stage, so patent applications are carried out in the same way.

## [Summary of the technology transfer]

## Technological Impact

The current and the loss of HTS wire are strongly influenced by wire temperature and penetrating flux density. Compared to copper wire, HTS wire is inferior in respect of mechanical strength and workability. After this fact was sufficiently understood, a new structure of HTS motors were devised, designed, assembled and tested. The main innovations in techniques of the developed trial machine are summarized as follows: ·Liquid nitrogen coolant, ·HTS armature AC coils, ·High magnetic permeability material to reduce perpendicular penetrating magnetic flux on HTS wires, ·Axial gap structure to simplify the structure of the armature winding cryostat. These techniques are already transferred to the corporation. Besides, the developed techniques for large capacity practical machines such as parallel connection method, current equalization method and AC loss reduction method of HTS wires were transferred too. These techniques are also suitable for rotating machines such as wind power generators.

## ●Market Impact

This kind of HTS motor will be on the market soon. By 2015, there will be a total of 518 machines worth 34.5 billion yen on sale. By 2020, there will be a total of 1310 machines worth 74.3 billion yen on the market. (According to the market research report of HTS machines that issued by ISTEC at February, 2007).

## ● Social Impact

Carbon dioxide can be decreased by 170.1 ton/year from 2015 and 388.5 ton/year from 2020.

## Project Background

By a chance, the research of HTS motor was started and a new construction of liquid nitrogen cooled HTS motor was considered. IHI had the interest for this new idea, and is active for its practical application.

## Funding History

1. From 2004 to 2006, the collaborative research contract.

2. From 2004 to 2006, the enterprise development funds.

## I ntellectual property protection

Pod which stored produced liquid nitrogen cooling HTS motor.

The number of patent applications : JP 19. PCT 3

“Axial gap high temperature

superconducting motor” Japanese Patent Application No.2006-204085, etc.

400kW, 250rpm liquid nitrogen cooling HTS motor under development.

## Turning point in the Project

The key point to make a HTS motor cooled by liquid nitrogen practical is to fully understand the features cooled HTS wire then to find the best structure. Another important thing is to catch the rapidly developing HTS wires characteristics and to apply to the practical application.