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What Are The Components Of A Brushless Motor?
- Dec 26, 2018 -

The brushless motor is composed of a permanent magnet rotor, a multi-pole winding stator, a position sensor, and the like. The position sensing commutates the current of the stator winding in a certain order according to the change of the rotor position (ie, detecting the position of the rotor pole relative to the stator winding, and generating a position sensing signal at the determined position, after being processed by the signal conversion circuit To control the power switch circuit, the winding current is switched according to a certain logic relationship). The operating voltage of the stator windings is provided by an electronic switching circuit controlled by the position sensor output.


The winding form of the brushless motor is only required to have a concentrated winding, a full-length distributed winding, a short-distance distributed winding, and the like. The difference in the form of the winding will affect the back EMF waveform of the motor, which in turn affects the performance of the motor. In general, the full-width concentrated winding can obtain a better trapezoidal back-EMF waveform, and the short-distance winding is beneficial to weaken the torque ripple.


There are three typical forms of rotor construction: surface-adhesive poles, embedded poles, and toroidal poles. The permanent magnet materials are mainly composed of aluminum-nickel-cobalt, ferrite and aluminum-iron-boron. Some new composite magnetic materials are also being gradually applied to brushless motors.


Position sensors commonly used in brushless motors are electromagnetic, photoelectric, and magnetically sensitive. Hall sensor is a kind of magnetic sensitive position sensor. It is small in size, easy to use and low in price. It is widely used in brushless motor control systems. Special integrated circuits can directly convert position signals such as Hall sensors into digital signals, which facilitates the digitization and intelligent realization of brushless motor control.