Views: 3 Author: Site Editor Publish Time: 2023-05-17 Origin: Site Inquire
A brushless motor is a direct current (DC) electric motor that operates without the mechanical brushes and commutator of a traditional brush motor. It has distinct advantages over a brush motor and is more economical in the long run, although the initial costs are higher. Brushless motors are used in various aspects of trenchless construction.
A brushless motor may be referred to as a BLDC or BL motor. Synonyms include electronically commutated motors (ECMs, EC motors) or synchronous DC motors.
The brushless DC motor consists of a motor body and a driver, and is a typical mechatronic product. A brushless motor refers to a motor without brushes and commutators (or collector rings), also known as a commutator-free motor. As early as the 19th century, when the motor was born, the practical motor produced was a brushless form, that is, an AC squirrel-cage asynchronous motor, which was widely used. However, asynchronous motors have many insurmountable defects, so that the development of motor technology is slow. Transistors were born in the middle of the last century, so brushless DC motors that use transistor commutation circuits instead of brushes and commutators came into being. This new brushless motor, called an electronically commutated DC motor, overcomes the shortcomings of the first generation of brushless motors.
1) Brushed motor When the motor is working, the coil and commutator rotate, the magnetic steel and carbon brush do not rotate, and the alternating change of the coil current direction is completed by the commutator and brush that rotate with the motor.
2) The brushless DC motor consists of a motor body and a driver, and is a typical mechatronic product. Since the brushless DC motor operates in a self-controlled manner, it does not add an additional starting winding to the rotor like a synchronous motor with heavy load under variable frequency speed regulation, nor does it cause oscillation and out of step when the load changes suddenly.
3) The brushed motor is a traditional product with relatively stable performance. The brushless motor is an upgraded product, and its life performance is better than that of the brushed motor. However, its control circuit is relatively complicated, and the aging screening requirements for components are relatively strict.
A brushless motor, that is, a brushless DC motor, is composed of a motor body and a driver, and is a typical mechatronic product. Since the brushless DC motor operates in a self-controlled manner, it does not add a starting winding to the rotor like a synchronous motor with heavy load under variable frequency speed regulation, and does not produce oscillation and out of step when the load changes suddenly. The permanent magnets of brushless DC motors with small and medium capacity are now mostly made of rare earth neodymium iron boron (Nd-Fe-B) materials with high magnetic energy levels. Therefore, the volume of the rare earth permanent magnet brushless motor is reduced by one frame size compared with the three-phase asynchronous motor with the same capacity.
The brushless DC motor uses semiconductor switching devices to realize electronic commutation, that is, electronic switching devices are used to replace traditional contact commutators and brushes. It has the advantages of high reliability, no commutation spark, low mechanical noise, etc. It is widely used in high-end recording sets, video recorders, electronic instruments and automated office equipment.
A brushless DC motor consists of a permanent magnet rotor, a multi-pole winding stator, and a position sensor. According to the change of the rotor position, the position sensor commutates the current of the stator winding in a certain order (that is, detects the position of the rotor magnetic pole relative to the stator winding, and generates a position sensor signal at the determined position, which is processed by the signal conversion circuit To control the power switch circuit, switch the winding current according to a certain logic relationship). The working voltage of the stator winding is provided by the electronic switching circuit controlled by the output of the position sensor.