NewsNews

Armature reaction of permanent magnet brushless DC motor

Author:qiwo motor Views:Close

2021-03-24 10:34

  In a permanent magnet motor, the air gap magnetic field is produced by the combined action of the permanent magnet magnetomotive force and the armature winding magnetomotive force. The influence of the magnetomotive force generated by the armature current on the air gap magnetic field when the motor is under load is called the armature reaction. In a brushed DC motor, its armature reaction magnetic field is orthogonal to the main pole magnetic field. The armature magnetic field causes the main magnetic pole magnetic field to be distorted. When the motor is in the state of the motor, the magnetic field at the front end of the motor magnetic pole is strengthened, and the magnetic field at the rear end of the magnetic pole weakens, and the weakened and strengthened magnetomotive force is basically equal. Due to the saturation of the magnetic circuit, the total magnetic flux of the main magnetic pole is weakened, and the greater the load, the more saturated the magnetic circuit and the more obvious the demagnetization effect. The armature reaction not only demagnetizes the magnetic field of the main magnetic pole, but also causes the magnetic flux of the main magnetic pole to be distorted, so that the magnetic field at the physical neutral surface of the magnetic pole is no longer zero, which brings disadvantages to the commutation. In the permanent magnet brushless DC motor, after all, its operating mechanism and structure are different from the brushed DC motor. Its armature response is related to the structure and saturation of the magnetic circuit, as well as the armature winding form, conduction mode and Factors such as the size of the state angle are related.

  This article is taken from ------"Permanent Magnet Brushless DC Motor Technology"