Summarize the types, advantages, disadvantages, and applications of various motors in one article
What is the difference between brushless motors and brushed motors? What is the difference between synchronous motor and asynchronous motor? Are all servo motors AC motors? Are all servo motors synchronous motors? Do stepper motors belong to DC motors or AC motors? Does the servo motor belong to servo motors, etc

DC motor - brushed motor

Even top and bottom students who have studied high school physics know that in order to study the force acting on an electrified conductor in a magnetic field, we have trained our left hand to a broken palm, which is also the principle of DC motors.

All motors are composed of a stator and a rotor. In a DC motor, in order to make the rotor rotate, the direction of the current needs to be constantly changed, otherwise the rotor can only rotate half a turn, just like a bicycle pedal. So DC motors require a commutator.

Broadly speaking, DC motors include brushed motors and brushless motors.

Brushed motor, also known as DC motor or carbon brush motor, commonly refers to a brushed DC motor that uses mechanical commutation. The external magnetic poles do not move, and the internal coils (armature) move. The commutator and rotor coils rotate together, while the brushes and magnets do not move. Therefore, the commutator and brushes rub against each other to complete the switching of current direction.

Disadvantages of brushed motors:

1. The sparks generated by mechanical commutation cause friction between the commutator and the electric brush, electromagnetic interference, high noise, and short lifespan.

2. Poor reliability, frequent failures, and the need for frequent maintenance.

3. Due to the existence of the commutator, the rotor inertia is limited, the maximum speed is restricted, and the dynamic performance is affected.

Since it has so many drawbacks, why is it still widely used? It has high torque, simple structure, easy maintenance (i.e. replacing carbon brushes), and is cheap.

DC motor - brushless motor

Brushless motor, also known as DC variable frequency motor (BLDC) in some fields, uses electronic commutation (Hall sensor), and the coil (armature) does not move and the magnetic poles move. At this time, the permanent magnet can be outside or inside the coil, so there is a distinction between outer rotor brushless motor and inner rotor brushless motor.

The structure of a brushless motor is the same as that of a permanent magnet synchronous motor.

However, a single brushless motor is not a complete power system, and brushless motors must be controlled by a brushless controller, also known as an electric controller, to achieve continuous operation.

The true determinant of its performance is the brushless electronic speed regulator (also known as ESC).

Generally, there are two types of driving currents for brushless motors, one is square wave and the other is sine wave.

The following content is from the understanding of DC brushless and permanent magnet synchronous motors by Zhihu author Pan Yunzhe. Lao Yuge looks good and shares it with everyone:

I have seen too many misunderstandings about brushless DC and permanent magnet synchronous motors. Today, I will conclude this issue in the Chinese world. If anyone disputes in the future about what BLDC and PMSM are and what the difference is, please refer to me directly. Ensure accuracy and correctness.

Brushless DC motor, also known as BLDC motor in English

Permanent magnet synchronous motor, also known as PMSM (Permanent Magnet Synchronous Motor) in English