Byoung-Yull Yang

Rotor Pole Design in Spoke-Type Brushless DC Motor by Response Surface Method

This paper proposes a novel rotor pole shape which consists of a uniform surface and an eccentric surface to make a sinusoidal magnetic flux density in air gap in order to reduce cogging torque, torque ripple, and harmonics of back-electromotive force waveform in spoke-type brushless DC motor. In the process of design and analysis, response surface methodology and the 2-D finite-element method are employed to obtain the rotor geometry and verify the results of the novel rotor pole shape

Novel topology of unequal air gap in a single-phase brushless DC motor

Most single-phase brushless DC (BLDC) motors have unequal air gaps to eliminate the dead point where the developed torque value is zero. These unequal air gaps deteriorate the motor characteristics in cogging torque. Thus in this paper a new topology of the unequal air gaps is proposed to solve this problem. As a result, it is proved by the finite element analysis and experimental results that the proposed air gap topology is very effective in reducing the cogging torque.

Design of Flux Barrier for Reducing Torque Ripple and Cogging Torque in IPM type BLDC motor

This paper proposes a novel designing method of flux barrier in order to reduce cogging torque and torque ripple in the interior permanent magnet type brushless DC motor (IPM type BLDC motor). IPM type BLDC motor is used for high speed and high torque. But IPM type BLDC motor can develop a large cogging torque that may cause noise and vibration. In that sense, this paper suggested that the directions of flux lines generated in the permanent magnet built in the rotor should be sinusoidal waveform distributed within the rotor by such designed flux barriers