Slotless brushless permanent magnet machines: influence of design parameters

The airgap field distribution, back-EMF waveform, winding inductances, and iron loss are predicted analytically from a 2-D polar co-ordinate model of a slotless brushless permanent magnet machine. The influence of pole number, magnet pole-arc and thickness, and magnetisation on the operational performance is then investigated, and a guide to design optimisation is presented.