Abstract： To solve the problem of power density reduction caused by the increasing of magnetic pole usage in the traditional Halbach permanent magnet array coreless axial flux permanent magnet generator (AFPMG), a novel three-segment Halbach permanent magnet array coreless AFPMG with variable auxiliary magnetic parameters (polar angle and magnetizing angle) was proposed. By the three-dimensional finite element method, the multi-objective optimization design was conducted to determine two parameters of polar angle and magnetizing angle of the auxiliary magnetic pole for the novel three-segment Halbach permanent magnet array, and the best auxiliary magnetic pole parameters were determined. The effects of magnetic pole structures on voltage waveform quality and power density of coreless AFPMG were compared and analyzed. The results show that the voltage distortion rate of the novel generator can be reduced from 2.40% to 0.44%. Compared with the traditional two-stage Halbach permanent magnet array and the traditional three-stage Halbach permanent magnet array coreless AFPMG, the power density of the novel permanent magnet generator can be significantly improved. The usage of permanent magnets in the novel permanent magnet generator is reduced by 16.68%, which in turn reduces the mass of rotor disc and makes it more suitable for stable power generation at low wind speeds.
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