Abstract
Conventional linear machine consists of only one stator and one mover. In this paper, a slotless permanent magnet (PM) linear motor with multiple tubular movers is proposed to improve the efficiency of stator field. The outer and inner movers can produce independent motions by interacting with the PM stator. It can be used in large systems requiring multiple driven elements to increase space utilization. The employment of tubular structure helps to reduce the flux leakage and improve the system working efficiency. The design concept and operating principle of the proposed linear machine are introduced. The magnetic field distribution is formulated by using Laplace's and Poisson's equations of magnetic vector potential. Numerical computation is also conducted on the flux field. It shows that the derived analytical result fits with finite element analysis (FEA) well. The influence of winding currents on the magnetic field distribution is also considered. The magnetic field distribution in four different working situations is simulated, i.e., nonexistence of working current, power supply for inner mover and outer mover respectively, and energizing both movers simultaneously. It is verified that the winding current does not affect the magnetic field distribution significantly and the multiple movers can achieve linear motions independently.
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