Impact of Stator Slot Shape on Cogging Torque of BLDC Motor

Abstract

Brushless DC (BLDC) motors have a wide range of applications in these modern days, such as electric vehicles, industrial robots, washing machines, pumps, and blowers. The brushless DC motors have many advantages when compared to induction motors and conventional DC motors, such as better speed control, noiseless operation, high efficiency, less maintenance, and a long life. Along with these benefits, there is one major disadvantage known as cogging, which causes undesirable effects in the motor such as noises and vibrations. BLDC motors have been widely used in automation and industrial applications due to their attractive features. There are certain parameters to be considered while designing a BLDC motor, such as its dimensions, number of windings turns, type of magnetic materials used, required torque, output current, slot-to-depth ratio, efficiency, temperature rise, etc. It is planned to minimize the cogging torque of BLDC motors by modifying the physical structure of the motors using mechanical methods, and the results will be evaluated using finite element analysis software. The results show that stator slot shapes (round, square, and airgap wedge) have cogging torques of 5.20 Nm, 0.4 Nm, and-0.296 Nm, respectively.