Electromagnetic structures of novel modular arc-linear flux switching permanent magnet motor (NMAL-FSPM), modular arc-linear flux switching permanent magnet motor that consists end permanent magnet (UPAL-FSPM) and modular arc-linear flux switching permanent magnet motor that doesn't consist end permanent magnet (UAL-FSPM) are proposed and comparatively researched in this paper by the finite element method (FEM). They are used for scanning system to directly drive objects rotate back and force within a limited angle instead of reduction gearboxes and kinematic mechanisms. Electromagnetic structures of these three kinds of motor are established. Magnetic field of stator end part, balance of back electromotive force (back EMF) and torque performance are researched. Compared with the UPAL-FSPM and the UAL-FSPM, the NMAL-FSPM has best field distribution of stator end part, most balanced back EMF and best torque performance. Based on the structure of the NMAL-FSPM, principle of slot-pole combination that is different from flux-switching permanent magnet motor is established. Then several electromagnetic structures with different slot-pole combination are established based on the principle. Back EMF and torque performance are compared and analyzed. The results show that 12-slots/13-poles exhibits the excellent performance.