No. 1058
	State-of-the-art technologies of high-speed drives and bearingless drives
	Investigating R&D Committee on state-of-the-art technologies of high-speed drives and bearingless drives
	Recently, high-speed drives have been developed owing to the improvements in semiconductor power converters, microprocessors, and bearings. If the rotational speed of a drive is increased, the power density of the drive can be improved. Thus, high-speed drive techniques provide small sized high-power motors and generators. Nowadays, many high-speed drives are developed for various applications. For instance, a small blower drive produces output power of 75 kW at 50,000 r/min, and this drive has magnetic bearings for the rotor suspension. Moreover, bearingless drives have been developed actively, which realize magnetic suspension by using the motor flux. In this report, outlines of high-speed drives and magnetic suspension technologies are described. Then, structures and control techniques of high-speed machines, magnetic bearings, and bearingless machines are explained focusing on the recent technology. Finally, applications of high-speed drives, such as compressors and spindles are introduced.
	©2006. The Institute of Electrical Engineers of Japan