Research on Thrust Fluctuation of Linear Motor with Trapezoidal Halbach Pole

Air core permanent magnet linear synchronous motor (ACPMLSM) with new permanent magnet structure was developed, and its key structural parameters were optimized to solve the problem of thrust and thrust fluctuation. Firstly, A new type of magnetic pole structure with trapezoidal Halbach arrangement is proposed. Then, the equivalent magnetization method is used to establish the mathematical model of the motor. The analytical formulas of motor magnetic field are derived respectively. Analyzed influence of polar-arc coefficient αρ, pole-height coefficient
$\beta$
, air gap height coefficient
$\gamma$
single side width factor of winding
$\chi$
on thrust and thrust fluctuation. Finally, through the trial production of the prototype and the physical experiment of the motor under two working conditions, the effectiveness of the motor designed by the new type of pole array to restrain the thrust fluctuation is verified.