Reduction of torque ripple in brushless DC motors

Author

Hwang, S.M. ; Lieu, D.K.

Author_Institution

Dept. of Mech. Eng., California Univ., Berkeley, CA, USA

Volume

31

Issue

6

fYear

1995

fDate

11/1/1995 12:00:00 AM

Firstpage

3737

Lastpage

3739

Abstract

For permanent magnet (PM) brushless DC motors, torque ripple, is an important origin of vibration, acoustic noise and speed fluctuation. In this paper, the output torque profile of a PM motor with one phase energized is decomposed into the commutation torque, the reluctance torque and the armature reaction according to their source origins. It verifies that the output torque profile is qualitatively equivalent to the BEMF profile for low reluctance motors. This paper discusses the effect of magnet pole shaping and magnet arc length on the output torque and torque ripple. A magnet edge shaping is proposed to design a trapezoidal BEMF motor without torque ripple, with minimal sacrifice of the maximum output torque

Keywords

brushless DC motors; commutation; machine theory; permanent magnet motors; reluctance motors; torque control; PM motor; armature reaction; back electromotive force motor; brushless DC motors; commutation torque; magnet arc length effect; magnet edge shaping; magnet pole shaping effect; output torque profile; permanent magnet motor; reluctance motors; reluctance torque; torque ripple reduction; trapezoidal BEMF motor; Brushless DC motors; Commutation; DC motors; Electromagnetic forces; Fluctuations; Magnetic field measurement; Magnetic flux; Permanent magnet motors; Reluctance motors; Torque;

fLanguage

English

Journal_Title

Magnetics, IEEE Transactions on

Publisher

ieee

ISSN

0018-9464

Type

jour

DOI

10.1109/20.489755

Filename

489755