The effect of stator slot number and pole number on motor performance in double-sided axial flux induction motors for electric vehicles

The aim of this study is to compare the axial flux induction motors (AFIM) used in electric vehicles by analyzing them with finite element method in different poles, number of slots and topologies. According to comparison, the most suitable one is determined as the drive motor for the reference electric vehicle. Output power of propulsion motor of an electric vehicle has been determined by considering different driving conditions. The dimensions and slot sizes of the induction motor that can provide the obtained output power have been calculated analytically. Double Rotor Axial Flux Induction Motors (DR-AFIM) calculations are presented as an example. Double Stator Axial Flux Induction Motors (DS-AFIM) and DR-AFIM topologies of 6-8-10 pole motors were analyzed using 3D models with combinations of 36, 48, 60 stator slot numbers and 52 rotor slot numbers in each motor. Copper is used in the rotor cage. In the stator windings, double-layer full pitch windings are used in each motor. Output powers, stator currents, efficiencies, power factors and current densities of the analyzed motors were compared at the same slip values. According to these comparisons, 8-pole DR-AFIM motors stand out in terms of the reference electric vehicle's ability to provide output power. The core saturations of the selected motor are shown on the quarter model, half axial 3D model of the motor. According to results, it is seen that the motor can be operated efficiently at an output power of nominal 50 kW, peak 75 kW and a rotor speed of 4000 rpm. In this study, AFIM in electric vehicles with double air-gap topologies were compared with different pole numbers and stator slot numbers. Accordingly, the most suitable one was chosen among them. The study will contribute to the researchers in terms of comparison of AFIM both in terms of double gap topologies and different pole and slot numbers.