The primary objective of the master thesis was to calculate and analyse magnetic conditions within the surface mounted permanent magnet electric motors. More precisely, the distribution of magnetic flux density within the air-gap and the resulting physical quantities such as the induced voltage, the electromagnetic torque and the cogging torque were calculated and analysed. The analysis was based on an analytical-numerical model of the surface mounted permanent magnet electric motor. First, the algorithms for calculation of magnetic flux density in the air gap were developed. Second, the complex permeance function for stator slotting is defined and calculated and the relative peremeance of the rotor magnets is added into the algorithm. The developed algorithm enables calculation of radial and tangential components of magnetic flux densities produced by both the rotor permanent magnets and stator current. Based on the resulting magnetic flux densities the algorithm enables the calculation of the induced voltage, electromagnetic and cogging torque. The results obtained with the analytical-numerical model were compared with a finite element based numerical model with linear B-H characteristic of feromagnetic material. A good agreement for the magnetic flux density and the induced voltage was obtained between the two models. However, the electromagnetic and cogging torque differs due to the chosen analytical method. Therefore, the finite element model was improved with the nonlinear B-H characteristic of the feromagnetic material. The new comparison showed a difference only in electromagnetic torques due to magnetic saturation of the motor core. Finally, the applicability of the developed algorithm was tested and demonstrated for different geometries of the surface mounted permanent magnet electric motors.
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