Design and modeling of tubular flux-switching permanent magnet linear motor

A novel tubular flux-switching permanent magnet (PM) linear motor is proposed in this paper. It takes the hybrid operating principle of conventional flux switching machines and excitation of permanent magnet poles. It helps to increase the magnetic flux density in air gaps, and improve the force output. The complementary phase is employed to reduce force ripples. Modular design methodology is utilized to improve the system interchangeability. The design concept and working principle are presented. The magnetic field distribution and thrust output are formulated analytically based on equivalent magnetic circuits. Numerical analysis is conducted on the magnetic field and thrust output to validate the operating principle of the proposed tubular flux-switching PM linear motor. It shows that the system can improve the thrust force density compared with conventional flux-switching machines. In addition, the proposed design helps to depress the force ripple and thus benefit the motion control of linear machines.