Affiliations: [a] School of Automation Science and Electrical Engineering, Beihang University, Beijing 100191, China | [b] Shenzhen Institute of Beihang University, Shenzhen, Guangdong 518000, China
Correspondence:
[*]
Corresponding author: Liang Yan, School of Automation Science and Electrical Engineering, Beihang University, Beijing 100191, China. E-mail:[email protected]
Abstract: Arrangement of permanent magnet (PM) poles and windings influences
the magnetic field and force output of linear machines
significantly. Various designs of PM linear machines have been
proposed by researchers, either putting PM poles inside and coils
outside, or vice versa. However, there is no systematic comparison
of these two types of designs in literatures. The purpose of this
study is to compare the magnetic field and force output of linear
machines with different PM and winding structure topologies. Halbach array can not only produce high flux density, but also has self-shielding effect. So it is employed for the analysis. Tubular structure is used because
it helps to reduce flux leakage and enhance the system output
performance. The magnetic field distribution of tubular linear
motors with internal and external PM poles are formulated with
Bessel functions, and the force output is thus obtained from Lorenz
force law. The analytical models of magnetic field and force output
are then validated with numerical computations. By utilizing the
verified analytical models, design optimization is conducted with
penalty functions for the two machine structures. The magnetic field
and force output performance are then compared. It shows that the
machine structure with internal PM poles helps to generate high
force output. The study in this paper can also be implemented for
the design of rotary machines.
Keywords: Halbach array, linear machine, magnetic field, force output, optimization
