Investigation of the Effect of Notches Opened on the Stator Shoe on the Cogging Torque by Parametric Analysis in Inner Rotor Single-Phase BLDC Motors

An asymmetric air gap is required for the self-starting capability of BLDC motors; however, this condition causes an increase in cogging torque, which negatively affects motor performance. In this study, a parametric analysis of notches opened on the stator legs was conducted to reduce cogging torque in inner rotor single-phase brushless DC (BLDC) motors. In the finite element analyses performed using Ansys Maxwell 2D software, notches with different positions and geometries were modeled on the stator legs in the air gap region. Within the scope of the parametric studies, the effects of the notches were examined in regions where the air gap is both at its minimum and maximum, and the optimum position was determined to be the region with the minimum air gap. During the production phase, a notched stator was manufactured, and the impact of these notches on the production processes and manufacturability was evaluated. According to the simulation results, the newly created notched stator model achieved approximately a 28.5% reduction in cogging torque.