Design of a linear vernier permanent magnet machine with high thrust force density and low thrust force ripple

This paper introduces a novel linear vernier permanent magnet machine (H-LVPMM) with high force density and low force ripple. The permanent magnets (PMs) on secondary uses Halbach array, which can provide a larger flux density in the air gap than that of the conventional surface-mounted PMs configurations, and the primary is composed of three modules, which are separated by two flux barriers. Moreover, the three-phase winding connections and the length of the two flux barriers are specially designed to minimize the cogging force and the ripple force. In order to show the superiority of the H-LVPMM, a conventional linear vernier permanent magnet machine using surface-mounted PMs (S-LVPMM) is built and compared to the proposed machine in terms of back electromotive force (back-EMF), cogging force, average thrust force, thrust force ripple, etc.