1. DC servo motors are divided into brushed motors and brushless motors.

The invention has the advantages of low cost, simple structure, large starting torque, wide speed regulation range, easy control, maintenance, inconvenient maintenance (carbon brush replacement), electromagnetic interference and high environmental requirements. It can be used in general industrial and civil fields and is sensitive to cost.

The brushless motor is small in size, light in weight, large in output, fast in response, fast in speed, small in inertia, stable in rotation and stable in torque. Its electronic commutation mode is flexible, and can use square wave commutation or sine wave commutation, the control is complex, and it is easy to realize intelligence. The motor is maintenance-free, has high efficiency, low operating temperature, low electromagnetic radiation and long life, and is suitable for various environments.

2. The AC servo motor is also a brushless motor, which is divided into synchronous motor and asynchronous motor. At present, synchronous motor is generally used for motion control, and its power range is large, which can achieve high power. The inertia is large, the rotation speed is low, and the rotation speed drops rapidly with the increase of power. It is therefore suitable for smooth operation at low speeds.

3. The rotor in the servo motor is a permanent magnet, which is controlled by the permanent magnet and controlled by the U/V/W three-phase current. The rotor rotates in the magnetic field. The motor has its own encoder to feed back to the driver. For comparison, adjust the angle at which the rotor turns. The accuracy (number of lines) of the encoder is determined by the accuracy of the servo motor.

The functional difference between AC servo motor and brushless DC servo motor:

AC servo is a little better because it is sine wave control and has less torque ripple. DVDC is a trapezoidal wave. But relatively speaking, DC servos are simpler and cheaper.

The main advantages of permanent magnet AC servo motors compared with DC servo motors are:

(1) There are no brushes and commutators, so the work is reliable and the maintenance and maintenance requirements are low.

(2) It is more convenient for stator winding to dissipate heat.

(3) The inertia is small, and it is easy to improve the rapidity of the system.

⑷ It is suitable for high-speed and high-torque working conditions.

⑸ It has smaller volume and weight under the same power.