Investigation of interior axially magnetized permanent magnet tubular linear machine used for electromagnetic launcher

Due to high winding utilization ratio, high thrust density, zero transverse end effect, and zero unilateral magnetic force, tubular linear machine (TLM) is a very suitable candidate for electromagnetic launcher. In this paper, two kinds of interior axially magnetized permanent magnet TLMs with and without slots are compared and evaluated with finite element method (FEM) from the aspects of magnetic field, thrust characteristic, thrust density, cogging force, and so on. It is shown that the slotted TLM has higher electromagnetic performance and thrust density, which is an important merit for the electromagnetic launcher. Then the slotted TLM is investigated more deeply by FEM. The material selection and structure optimization are researched to improve the electromagnetic performance. The thrust characteristic is much improved after optimization.