Performance analysis of the different combinations of slots and poles of outer-rotor direct-drive permanent magnet motor

Abstract：To achieve the goal of miniaturization and energy saving of the tobot, the high performance direct-drive permanent magnet motor has become the first choice of the robot drive system.The winding factor and the selection principle of the combinations of poles and slots for the concentrated windings of direct-drive permanent magnet motor were analyzed herein.According to the technical requirements of the robot for the motor, the winding factor analysis and the principle of combinations of poles and slots were chosen to select the required combinations of poles and slots, and the harmonic winding coefficients and amplitude values at different combinations of poles and slots were analyzed, and then several combinations of poles and slots with better harmonic coefficients were obtained.With the same structural parameters and materials, the finite element simulation model was established, the air gap magnetic density and the back EMF under no-load state were analyzed, and the performance of electromagnetic torque and its fluctuation as well as efficiency under different load were analyzed, and then, the influence of different combinations of poles and slots on the design and performance of the motor was obtained.The results provided an important reference for the further optimization of the outer-rotor direct-drive permanent magnet motor and the research of the robot direct-drive control system.

Keyword：direct-drive permanent magnet motor;outer-rotor;robot;combination of slot and pole;