An important difference between the servo drive and the frequency converter is that the frequency conversion can be without an encoder, while the servo must have an encoder for electronic commutation. The following ADTECH servo driver manufacturer's editor will give you a detailed introduction to the specific differences between the two, the specific content is as follows:
1. Common ground between the two: AC servo technology itself is the reference and application of frequency conversion technology, on the basis of the servo control of DC motor through the PWM mode of frequency conversion to imitate the control mode of DC motor, that is to say, AC servo motor must have the link of frequency conversion: Frequency conversion is the alternating current of 50 and 60HZ of power frequency is rectified into direct current first, and then through various kinds of transistors (IGBT, IGCT, etc.) that can control the gate, the inverter is adjusted into a frequency adjustable waveform similar to sine and cosine pulsation electricity through carrier frequency and PWM. Because the frequency is adjustable, the speed of AC motor can be adjusted (n= 60F/P, N speed, F frequency, P pole logarithm)
2. Talk about frequency converter: a simple frequency converter can only regulate the speed of AC motor. In this case, it can be either open or closed loop depending on the control mode and frequency converter, which is the traditional V/F control mode. Many frequency conversion has been through the establishment of mathematical model of ac motor stator magnetic field UVW3 phase into can control the motor speed and torque of the two current component, most of the famous brand can control the torque converter is controlled by such way moment, UVW output of each phase with hall effect current detection device, PID regulation of the current loop formed by closed-loop negative feedback after sampling feedback; ABB frequency conversion and this method is different from direct torque control technology, specific please refer to the relevant information. This can control both the speed of the motor and the torque of the motor, and the speed control accuracy is better than V/F control, encoder feedback can also be added or not, when the control accuracy and response characteristics are much better.
3, talk about servo drives: servo driver in the development of the premise of frequency conversion technology, inside the drive current loop, velocity loop and position loop (inverter without the ring) have been more accurate than general frequency conversion control technology and algorithm of computing, powerful in function than the traditional servo many, the main point can be accurately position control. Through the upper controller sends a pulse sequence to control the speed and position (of course also some internal integration servo control unit directly or through the bus communication way to set the parameters such as position and speed) in the drive, drive internal algorithm and a faster and more accurate calculation and performance more superior electronics is superior in frequency converter.
4. Motor: Servo motor of the material, structure and processing technology is far higher than the frequency inverter ac motor driven (general ac motor or constant torque and constant power and other kinds of variable frequency motor), that is to say, when the driver output current, voltage, the power of the frequency change quickly, the servo motor can vary according to the action of the power supply change response, The response characteristics and anti-overload ability are much higher than that of AC motors driven by frequency converters, and the serious differences in the motor are also the fundamental reason for their different performance. That is to say, it is not that the frequency converter can not output the power signal that changes so fast, but the motor itself can not react, so in the internal algorithm setting of frequency conversion in order to protect the motor to do the corresponding overload setting. Of course, even if the output capacity of the frequency converter is not set, it is limited, and some frequency converters with excellent performance can be directly driven!