Analysis and Design of 3 kW Axial Flux Permanent Magnet Synchronous Motor for Electric Car

Axial flux topology machines are extremely advantageous when used in electric vehicles. The machine design of this topology presents some challenges, considering that it must meet the vehicle's and tracks prerequisites. This work presents a design methodology for axial flux machines focusing on electrical traction based on the comparison between the analytical and computational resolution by the finite element method. Based on the pre-established resistant torque and power, as well as the rated data of the vehicle, an analytical method is used that allows the determination of the main parameters of a permanent magnets axial flux machine. Then, the principle of magnetic circuit theory was applied to determine the flux densities in the ferromagnetic material of the armature, rotor, permanent magnets and air gap, the latter, as a starting point, is adopted at its maximum value and from this, the flux densities on other parts of the machine are estimated. After flux densities estimation, it is verified that the induction levels achieved are under the saturation induction level in ferromagnetic material, enabling the development of a model in computational simulation software with numerical resolution by the finite element method Ansys Maxwell in magnetostatic regime. Once the simulation was done, the inductions were compared with those obtained by analytical method. It is verified that the absolute errors obtained between the two methods present values less than 10%, resulting in the construction of a 3 kW prototype for installation in a vehicle for educational purposes. The bench tests carried out on the prototype and the test on the track up to the adopted maximum limit speed indicated that the torque results reached the prerequisites of 30 km/h on the track.