In this paper, we propose two new methods to decrease the torque ripple for an arc permanent magnet linear synchronous motor (Arc PMLSM), which will be applied on the next generation large telescope. By connecting different phase windings of different stators, the problem of unbalanced three-phase winding was solved. Compared with the primary three-phase winding, there were fewer harmonics in the current. Besides, by changing the angle between two stators, the end cogging force of different stators was counteracted. After these methods were adopted on the optimized Arc PMLSM, the torque ripple was decreased from 3.2% to 0.65%, which can satisfy the requirement of tracking accuracy for telescope.