Design and optimization of dual excitation linear synchronous motors with internally placed permanent magnets

Dual excitation linear synchronous motors (LSM) with internally placed permanent magnets (PM) were proposed to overcome the shortcomings of electromagnetic excitation linear synchronous motors used in maglev trains,which include limited suspension force and more excitation energy. The structure and feature of this kind of linear motor were introduced. Then the parameters of permanent magnets and electromagnetic windings were analytically calculated,and the stress of secondary was checked. A finite element analysis model of the motor was built,and the distribution of magnetic field was solved. Four important dimensional parameters of the motor secondary were optimized through comparing the no-load suspension force and the no-load leakage coefficient that worked out with finite element method. Compared with an electromagnetic excitation motor and the other dual excitation motor,the proposed linear motor has some advantages,such as bigger suspension force,less excitation energy,better heat-sinking capacity of permanent magnets.