As ac servo drive, not only need to implement a wide range, constant torque, speed, and should be able to pass the superior position control device (such as CNC) realize the position control, therefore, no matter general servo or dedicated server is a kind of position control as the main characteristics of the ac motor control system, its speed and torque control in the service position control. As a result, they can be used with CNC, in order to realize the coordinate axis position control requirements, this is one of the things in common.

Ac servo drive demand for speed is higher than inverter, ac spindle driver, and early square wave permanent magnet synchronous Motor based on classical control theory (Brush Less DC Motor - BLDCM Motor, also known as brushless DC Motor) is a special ac servo is rarely used. Therefore, the current general servo or special servo needs to complete the drive manufacturer specially designed sinusoidal Permanent Magnet Synchronous servo Motor (Permanent - all Synchronous Motor, all-digital fuzzy Motor), the second is the common ground.

Current of ac servo drive is adopted digital closed-loop vector control, PWM frequency conversion technology, so the drive of the main circuit adopts "pay has a hand in the topology of the PWM inverter, the use of power electronic devices in the third generation of" composite "device IGBT and the fourth generation device is dominant power integrated circuit of IPM. As a result, they are in control theory and technology, main circuit topology structure, the use of power electronic devices, etc, also, this is the third in common.