The brushless DC motor is composed of a motor body and a driver, and is a typical mechatronic product. The DC motor has a fast response, a large starting torque, and a rated torque from zero speed to rated speed.
The brushless DC motor is composed of a motor body and a driver, and is a typical mechatronic product. A brushless motor is a motor without a brush and a commutator (or collector ring), also known as a commutatorless motor. As early as the birth of the motor in the 19th century, the practical motor produced was the brushless form, that is, the AC squirrel-cage asynchronous motor, which has been widely used. However, asynchronous motors have many insurmountable defects, resulting in slow development of motor technology. In the middle of the last century, transistors were born, so DC brushless motors using transistor commutation circuits instead of brushes and commutators came into being. This new type of brushless motor is called an electronically commutated DC motor, which overcomes the shortcomings of the first generation of brushless motors.
The stator windings of the motor are mostly made into a three-phase symmetrical star connection, which is very similar to the three-phase asynchronous motor. A magnetized permanent magnet is attached to the rotor of the motor. In order to detect the polarity of the rotor of the motor, a position sensor is mounted in the motor. The driver is composed of power electronics, an integrated circuit, and the like.
DC motors have fast response, large starting torque, and can provide rated torque from zero speed to rated speed. However, the advantages of DC motors are also its shortcomings, because DC motors must produce constant rotation under rated load. For the performance of the moment, the armature magnetic field and the rotor magnetic field must be maintained at 90°, which is achieved by the carbon brush and the commutator.
