Design and Analysis of Double-sided Modular Composite Excitation Permanent-magnet Linear Vernier Machine

Conventional double permanent-magnet linear vernier motors eliminate the normal force found in unilateral motors; however, they have low thrust density, large thrust fluctuations, significant vibration, and poor phase-to-phase fault tolerance. Therefore, a new double permanent-magnet linear vernier motor is proposed by combining the modular structure with the composite excitation method. The modulation method of composite excitation can effectively increase the average thrust of the motor and reduce thrust fluctuations, and the modular structure can effectively improve the phase tolerance performance of the motor. First, the topology of the motor is determined, from which an equivalent magnetic network model is derived to analyze the magnetic circuit direction and magnetic field distribution of the motor. Second, the composite excitation mechanism is analyzed and verified using finite element analysis. Third, the main parameters of the motor are analyzed and optimized, and the performance is compared with that of the bilateral modular motor and consequent-pole motor. The findings indicate that the electromagnetic performance of the motor is significantly superior to those of the two aforementioned motors. Finally, the temperature field distribution and vibration characteristics are analyzed and compared. The results show that the proposed motor can suppress the vibration problem of linear magnetic field modulation-type motors to a certain extent. This work serves as a solid foundation for further research and implementation of double-sided modular composite excitation permanent-magnet linear Vernier machines.