In the case of high-end AC asynchronous servo, many drives are high-end frequency converters with encoder feedback closed-loop control. In addition, the structure of the servo motor is different from that of the ordinary motor, and it must meet the requirements of fast response and accurate positioning.
On the basis of the servo control of the DC motor, the PWM method of frequency conversion is used to imitate the control method of Conveyor Pulleys Suppliers the DC motor, which means that the AC servo motor must have the frequency conversion. Frequency conversion is to first rectify the 50, 60HZ AC power of the industrial frequency into DC power, and then through various transistors (IGBT, IGCT, etc.
But the servo closes the current loop speed loop or position loop for control, which is a big difference. Link.) that can control the gate, adjust the carrier frequency and PWM to invert it into an adjustable frequency waveform similar to sine and cosine Due to the adjustable frequency, the speed of the AC motor can be adjusted (n=60f/p, n speed, f frequency, p pole pairs). The so-called servo is to satisfy accurate, precise, and fast positioning.
At present, most of the AC servo motors circulating on the market are permanent magnet synchronous AC servos, but this kind of motor is limited by technology and it is difficult to achieve a large power.The AC servo technology itself is borrowed from and applied the technology of frequency conversion. Synchronous servos of more than ten KW are very expensive, so that they can be used in the field.
Frequency conversion is a necessary internal link of servo control, and there is also frequency conversion in the servo drive (stepless speed regulation is required). As long as it is satisfied, there will be no competition for servo frequency conversion.The basic concept of servo is accurate, precise and fast positioning
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