Servo is a closed-loop control system, and the inverter usually works in open-loop control, so the inverter cannot be compared with servo in terms of speed and accuracy.
Frequency conversion is only a part of the servo. The servo is precisely controlled by the closed loop on the basis of frequency conversion to achieve a more ideal effect. Inverter is just a V-F conversion, a device used to control the motor. The servo is a closed-loop system. Simply put, the inverter mainly controls the rotation speed of the motor.
Servo can not only control speed, but also control position and movement amount, force distance and positioning, so as to achieve accuracy and stability without crashing due to frequency conversion.
The servo can not only achieve the above functions, but also generate a closed-loop system to avoid the radiation generated by the inverter.
The inverter will also generate a large amount of heat during the frequency conversion process, resulting in temperature increase and sound, and the servo system will not have such consequences.
Therefore, the effect achieved by the servo system is unmatched by the frequency conversion motor.
In fact, everyone has neglected a problem, that is, the servo motor is a synchronous motor, its rotor speed is the actual speed of the motor, there is no speed difference, and the inverter control object is an asynchronous motor, there is a slip between the actual speed and the rotor speed, so its own motor is not very stable at speed.
The basic concept of servo is accurate, accurate and fast positioning.
Frequency conversion is only a necessary internal link of servo control, and frequency conversion also exists in servo drivers (Stepless speed regulation).
However, the servo controls the current loop speed loop or the position loop, which is a big difference.
In addition, the structure of the servo motor is different from that of the ordinary motor, and it is necessary to meet the requirements of rapid response and accurate positioning.
The cost of synchronous servo is very expensive, so AC asynchronous servo is used when field applications allow it. At this time, many drives are high-end inverters with encoder feedback closed-loop control.
The so-called servo is to meet the requirements of accurate, accurate and fast positioning, so only high-end products often adopt servo systems.