Abstract
Rare-earth magnets, which have high energy product, have been widely used in several industrial applications such as voice coil motors for hard disk drives, MRI for medical devices and motors for electric vehicle. In order to realize a small and high performance device, the magnetic field analysis techniques are required. In this paper, we applied the magnetic field analysis to design the permanent magnet synchronous motors into the rail traction system. In the inverter fed motor drive, the eddy current loss in the permanent magnet increased. We simulated the effect that eddy current was decreased by using a divided permanent magnet. Furthermore, the permanent magnet tends to be demagnetized due to the effect of a demagnetizing field formed at high temperatures. However, according to our analysis, demagnetization does not occur within the range of our design specifications. Also, we performed magnetic field analysis assuming a pulse-type magnetization process and designed an optimal magnetizing coil.
