Robust design for reducing cogging torque in surface‐mounted permanent magnet synchronous motor considering tolerances of sub‐components

This study deals with a robust design for cogging torque reduction considering the production tolerances of motor sub‐components, which is related to the dimensions of the permanent magnet and stator core shape. A 14‐pole and 12‐slot fractional slot concentrated winding motor is employed as the design model. Prior to a robust design, an initial model was implemented to satisfy the torque demand within some constraints. In the robust design, the main design variables were first selected for the design of experiment (DOE). The interaction effects were investigated using the full factorial design, which is one of the DOE techniques. Next, the direction of design variables to minimise the cogging torque and improve the signal‐to‐noise ratio were confirmed using the Taguchi method. Then, the response surface methodology was implemented based on the result from the Taguchi method to yield an optimum value of the design variables and approximate equivalent polynomial equation. Finally, the normal distribution curve of the cogging torque was simply determined by the equivalent polynomial equation using the Monte‐Carlo method taking production tolerances based on the process capability of the sub‐components into consideration.