What are the advantages of brushless DC motors? There […]
What are the advantages of brushless DC motors?
There are two main types of DC motors, brushed DC motors and brushless DC motors. Especially brushless DC motors are widely used in industrial production and daily life due to their excellent working characteristics. This article introduces the working principle and composition of brushless DC motors. .
A Brief Introduction of Brushless DC Motor
The brushless DC motor (BLDC) replaces the mechanical commutator with an electronic commutator, so the brushless DC motor not only has the characteristics of good speed control performance of the DC motor, but also has the simple structure of the AC motor, no commutation spark, and reliable operation And easy maintenance and other advantages.
The brushless DC motor is mainly composed of a rotor made of permanent magnet materials, a stator with coil windings and a position sensor (optional). It can be seen that it has a lot in common with a DC motor. The structure of the stator and the rotor are similar (the original stator becomes the rotor, and the rotor becomes the stator), and the winding connections are basically the same. However, they have an obvious difference in structure: the brushless DC motor does not have the commutator and brushes in the DC motor, instead it is a position sensor. In this way, the motor structure is relatively simple, reducing the cost of manufacturing and maintenance of the motor, but the brushless DC motor cannot automatically commutate (phase), and the sacrifice is the increase in the cost of the motor controller (such as the same three-phase DC motor, there are The drive bridge of the brushed DC motor needs 4 power tubes, and the drive bridge of the brushless DC motor needs 6 power tubes).
Brushless DC motors have the following characteristics:
1. The brushless DC motor has good external characteristics and can output large torque at low speed, so that it can provide large starting torque;
2. The brushless DC motor has a wide speed range and can run at full power at any speed;
3. The brushless DC motor has high efficiency and strong overload capacity, which makes it have excellent performance in the driving system;
4. The brushless DC motor has a good regenerative braking effect. Because its rotor is made of permanent magnet material, the motor can enter the generator state when braking;
5. The brushless DC motor is small in size and high in power density;
6. The brushless DC motor has no mechanical commutator and adopts a fully enclosed structure, which can prevent dust from entering the motor and has high reliability;
7. The drive control of the brushless DC motor is simpler than that of the asynchronous motor.