1, servo driver definition:
Servo drive: under the premise of the development of frequency conversion technology, the current ring, speed ring and position ring (the frequency converter does not have the ring) inside the servo drive have carried out more accurate control technology and algorithm than the general frequency conversion, and are much more powerful than the traditional servo in function, and the main point can be accurate position control. The speed and position are controlled by the pulse sequence sent by the upper controller (of course, some servo internal integrated control unit or directly set the position and speed parameters in the servo drive through the bus communication), the algorithm and faster and more accurate calculation and better performance of the electronic devices within the servo drive make it more superior to the frequency converter.
Motor: The material, structure and processing technology of the servo motor is much higher than that of the AC motor driven by the inverter (general AC motor or all kinds of variable frequency motors such as constant torque and constant power), that is to say, when the servo drive output current, voltage and frequency change quickly, the servo motor can produce a response to the action change according to the power change. The response characteristics and anti-overload ability are much higher than the AC motor driven by the inverter, and the serious differences in the motor are also fundamental to the different performance of the two. That is to say, it is not that the inverter can not output the power signal that changes so fast, but that the motor itself can not react, so the corresponding overload setting is made in order to protect the motor when the internal algorithm is set. Of course, even if the output capacity of the inverter is not set, some good performance of the inverter can be directly driven!
2, frequency converter definition:
Simple frequency converter can only adjust the speed of the AC motor, then you can open loop or closed loop depending on the control mode and frequency converter, which is the traditional sense of V/F control mode. A lot of frequency conversion has been established through the mathematical model to convert the stator magnetic field UVW3 phase of the AC motor into two current components that can control the motor speed and torque. Most of the famous brand frequency converters that can control the torque use this way to control the torque. The output of each UVW phase needs to add a Hall effect current detection device. PID regulation of the current loop with closed-loop negative feedback is formed after sampling feedback. ABB's frequency conversion also proposes a direct torque control technology different from this way, please refer to the relevant information for details. In this way, both the speed of the motor can be controlled and the torque of the motor can be controlled, and the control accuracy of the speed is better than that of the v/f control, and the encoder feedback can be added or not, and the control accuracy and response characteristics are much better when added.
Servo drivers and frequency converters have several commonalities:
The technology behind AC servo systems is essentially based on frequency conversion techniques. It is an imitation of DC servo control, which is achieved by using PWM techniques to mimic the control of DC motors. This implies that the conversion of the frequency is an essential element in the AC servo driver. Frequency converters convert the 50/60Hz AC power supply into DC power, and the controllable gates of various transistors (such as IGBT and IGCT) use carrier frequencies and PWM to obtain pulsating waveforms similar to sine and cosine functions. Since the frequency is adjustable, the speed of the AC motor can be regulated as well (n= 60f/p, where n is the speed, f is the frequency, and p is the number of magnetic poles).
Therefore, the use of frequency converters is one of the fundamental commonalities between servo drivers and frequency converters. Both devices enable users to regulate the speed of an AC motor, which is necessary to ensure precise and reliable control. Consequently, the differences between servo drivers and frequency converters lie primarily in the method by which they regulate the motor speed. Servo drivers use feedback control systems to regulate the motor speed and position accurately. Frequency converters rely on PWM to modify the motor's frequency and hence its speed. Nevertheless, both systems depend on the AC motor's ability to operate at various speeds, which is only possible because of the presence of a frequency conversion device.
In conclusion, servo drivers and frequency converters are two fundamental components in modern industrial automation systems. They allow engineers to regulate the speed of AC motors, which is essential for achieving accurate and reliable control. Although these devices differ in their configuration and control mechanisms, they share the same origin, which is the frequency conversion technology.
