MAGNETIC FIELD OF TUBULAR LINEAR MACHINES WITH DUAL HALBACH ARRAY

Permanent magnet (PM) array affects flux field distribution of electromagnetic linear machine significantly. A novel dual Hal-bach array is proposed in this paper to enhance flux density in the air gap, and thus to improve output performance of linear machines. Magnetic field in the three-dimensional (3D) space of a tubular linear machine with dual Halbach array is formulated based on Laplaceʹs and Poissonʹs equations. Numerical result from finite element method is employed to simulate and observe the flux distribution in the machine. A research prototype and a testbed are developed, and experiments are conducted to validate the analytical models. The study is useful for analysis and design optimization of electromagnetic linear machines.