Magnetic Field Modeling of Halbach Permanent ...

In this paper the magnetic flux density distribution of a Halbach permanent magnet array for magnetically levitated planar motor is modelled analytically. The analytical first order harmonic model is derived initially from Fourier harmonic waves of magnetic field. Then the real magnetic field of a Halbach permanent magnet array is measured on a Teslameter-centred measurement platform and the measured results are analysed. Next, the key parameter of analytical model is fitted and the analytical model and the measured real magnetic field are compared. The analytical and compared results indicate that the analytical model accords with the measured real magnetic field, in addition, the error root of mean square between the model value and measured value of sinusoidal magnetic flux density distribution is less than 43.554 Gauss, and the relative error to the amplitude of sinusoidal magnetic flux density distributin is less than 5%. The constructed first order harmonic model represents analytically the magnetic flux density distribution of Halbach permanent magnet array and it will facilitate the modelling of electromagnetic force/torqe and the commutation of the magnetically levitated planar motor.