Electromagnetic Performance of Arc-Linear Permanent Magnet Synchronous Motors with Different Slot/Pole Number Combinations

In the design of conventional arc-linear permanent magnet synchronous motors (AL-PMSM), in order to improve the fundamental winding factor, the winding form of the motor is selected as fractional slot concentrated winding with a difference of 1 between the pole numbers and slot numbers. However, this winding form of the motor would be subjected to an unbalanced magnetic pull. To eliminate the influence of the unbalanced magnetic pull and maintain the winding factor, the fractional slot overlapping winding is adopted. Using the unit motor with 9-slot/10-pole, 12-slot/10-pole, and 18-slot/10-pole, three AL-PMSMs are designed while keeping the stator core structure of the three motors unchanged. Slot/pole number combination is changed by changing the winding form and the number of permanent magnets. Finite element analysis is conducted on three AL-PMSMs to compare their air gap flux density, back electromotive force, and electromagnetic torque. Through simulation analysis, the performances of the three motors are found to be similar, but the AL-PMSM composed of 18-slot/10-pole unit motors is most severely affected by local saturation at the end teeth of the stator.