Design and Analysis of a Linear Interior Permanent Magnet Vernier Machine

The linear permanent magnet vernier machine (LPMVM) is the combination of the linear permanent magnet machine and vernier machine, which yields high thrust density at low speed and thus is a preferable solution in the direct-drive linear-motional applications [1]. In order to further improve the thrust density of the LPMVM, many new configurations have been proposed in recent years, such as the double-stator spoke-type LPMVM [2], the LPMVM with Halbach permanent magnet (PM) array [3], the LPMVM with consequent-pole and Halbach PM array [4], the linear stator PM vernier machine [5], and so on. It is worth noted that the flux density of the tooth of the LPMVM is even smaller that of the conventional linear PM (CLPM) machines due to the multi-polar and fewerteeth structure. In order to improve the flux density and the thrust of the LPMVM, the linear interior permanent magnet vernier machine (LIPMVM) is proposed in this paper, in which the PMs are inserted into the stator core. Due to the improvement of the flux density and additional reluctance thrust, the average thrust of the proposed LIPMVM is significantly higher that of the conventional linear surface PM vernier machines (LSPMVM).