Research on a Novel Concentrated-Winding and Unequal Tooth Linear Permanent Magnet Vernier Machine

In this article, a novel concentrated-winding and equal tooth structure linear permanent magnet vernier machine (ET-LPMVM) is developed to facilitate coils embedded in the armature while maintaining performance equivalent to the conventional linear permanent magnet vernier machine (C-LPMVM). The electromagnetic parameters of ET-LPMVM, such as no-load air-gap flux density, no-load back electromotive force (EMF), inductance, and thrust, are compared and analyzed with C-LPMVM. The electromagnetic performance of ET-LPMVM is verified by a semi-analytical method and FEM, and the results of both methods are basically the same. To further enhance the machine’s performance, a novel unequal tooth linear permanent magnet vernier machine (UNET-LPMVM) is proposed based on the ET-LPMVM. The unequal tooth structure is employed to enhance the back EMF and thrust density, and the thrust improvement mechanism of the proposed machine is analyzed by the Maxwell stress tensor (MST) method. Minimum thrust ripple and high thrust are obtained by optimizing the key parameters of the proposed machine. Compared with ET-LPMVM and C-LPMVM, the average thrust of the proposed UNET-LPMVM is 36.43% and 28.73% higher than the ET-LPMVM and C-LPMVM, respectively. Furthermore, the thrust ripple of the proposed machine is reduced from 18.84% to 2.96%. The analysis results show that the proposed UNET-LPMVM has a better flux modulation effect and thrust characteristics.