DC servo motors are divided into brushed and brushless motors. The brushed motor has low cost, simple structure, large starting torque, wide speed range, easy control and maintenance, but it is easy to maintain (replace the carbon brush), it will produce electromagnetic interference, and has certain requirements for the environment. Therefore, it can be used in cost-sensitive general industrial and civil applications. The brushless motor has small size, light weight, large output power, fast response, fast speed, small inertia, stable rotation and stable torque.
DC servo motor is easy to realize intelligent, and its electronic commutation method is flexible, which can be square wave commutation or sine wave commutation. The motor is maintenance-free and has no carbon brush losses. High efficiency, low operating temperature, low noise, very little electromagnetic radiation and long life. It can be used in various environments.
The AC servo motor has good speed control characteristics, can be smoothly controlled in the entire speed range, almost no oscillation, the efficiency is as high as 90%, less heat generation, high speed control, high precision position control (depending on the encoder accuracy), rated Input in the work area, it can achieve constant torque, low inertia, low noise, brushless wear and maintenance-free (suitable for dust-free and explosive environments). AC servo motors are also brushless motors, divided into synchronous motors and asynchronous motors. Currently, synchronous motors are commonly used in motion control. Their power range is large, the power can be large, the inertia is large, the maximum speed is low, and the speed increases with the power. Reduced speed at a uniform speed, suitable for stable operation at low speed.
The disadvantage of AC servo motor is that the control is more complicated, the driver parameters need to be adjusted in the field to determine the PID parameters, and more connections are needed to support its operation.