Torque Ripple Minimization of Interior Permanent Magnet Brushless DC Motor Using Rotor Pole Shaping

In this paper effort is made for the torque ripple minimization of a 70 W, 24 Volt, 350 rpm, interior permanent magnet brushless DC (IPM BLDC) motor. The rotor pole shaping along with the pole shifting is analyzed. The results obtained from FE analyses have been discussed. The proper design and geometry of the motor reduces the cogging torque and the proper excitation reduces the mutual torque ripple. The torque ripple minimization using only the stator excitation makes the controller inefficient as well as costlier. Using the methods used in this paper, the torque ripple of the IPM BLDC motor is reduces and also the average torque is improved. In this method concept of magnet shifting is utilized for the torque improvement and rotor saliency is provided to reduce the cogging torque. Detailed analysis and explanation is given in this paper. The wide range of torque control by changing the switching intervals is an additional advantage of this design.