A Novel Consequent-Pole Modular-Mover Linear Permanent Magnet Vernier Machine for Thrust Ripple and Cost Reduction

Abstract

Recently, linear permanent magnet vernier machine (LPMVM) is attracting more and more attention due to its high thrust density, high efficiency, and simple structure at low-speed operation, which makes it a preferable solution for direct-drive linear motion applications. In order to further reduce the thrust ripple and the cost of LPMVM, a novel consequent-pole modular-mover LPMVM (CM-LPMVM) is proposed and analyzed in this article. Due to the dual-flux-modulation effect, the proposed CM-LPMVM can exhibit a low thrust ripple (∼3.2% of the average thrust) and high thrust density (∼387 kN/m <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> ) at a low current density of 3 A/mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , as well as reduce nearly half of the PM usage at the same time. The performance improvement of the proposed CM-LPMVM is verified by the comparison to a regular modular-mover LPMVMs, using the finite-element method. Finally, three prototypes are built and tested. The experimental results match well with the analytical data, showing the superiority of the proposed CM-LPMVM.