关键词: 空心杯电机, 极弧系数, 瓦片型磁钢, 环形磁钢

Abstract: The common structure of permanent magnet for coreless motor was introduced. Aiming at the magnetic flux of permanent magnets, the advantages and disadvantages of six topological structures, such as tile magnet and ring magnet, radial and parallel magnet, yoke or not, were analyzed by finite element simulation. The results show that for the same motor volume, the parallel magnetized ring magnet has the largest average air-gap magnetic density and nearly sinusoidal air-gap magnetic density waveform, which is better than other topologies. When the total volume of the ring magnet and the magnetic yoke is certain, the ring magnet does not need the magnetic yoke, because the increase of the ring magnet is not enough to compensate for the magnetic flux loss caused by the decrease of the magnet volume. These two results provide a basis for the selection of permanent magnets for coreless motors. The calculated polar arc coefficient was also calculated, which could provide reference for the design of coreless motor.

Key words: coreless motor, pole arc coefficient, tile magnet, ring magnet