In this paper, the static and dynamic electromagnetic performance, including the airgap field distribution, the back-emf waveform, the cogging torque, and the torque-speed characteristic and the efficiency, of three alternative Halbach permanent magnet brushless motors, employing anisotropic bonded NdFeB Halbach cylinder with and without rotor back-iron, as well as segmented Halbach cylinder with sintered NdFeB magnets, are compared by finite element analyses and measurements, together with a conventional radially magnetized permanent magnet brushless motor.
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