In today's industrial automation, the frequency converter is almost a "necessary magic weapon". Whether you are a novice or a veteran, as long as you are involved in industrial control, inverter parameter setting is always a topic that can not be bypassed. We often jokingly say, know how to play around with the frequency converter, mastered the equipment operation of the "life and death switch". This article will be in-depth analysis of inverter parameter settings, so that you no longer for those "difficult" settings to worry about.
What is a frequency converter? Variable Frequency Drive (VFD) is a power device used to adjust the speed of asynchronous motors. Its working principle is not difficult to understand, by adjusting the power frequency to change the motor speed. Based on the formula n=60f/p(1-s), we can see that the change of frequency is the core. Therefore, most of the parameter settings of the inverter revolve around how to accurately control the frequency and voltage to keep the motor running stably.
Basic parameter settings in detail 一、Control mode Before making any settings, the first thing to be clear is the control mode of the inverter. This may be speed control, torque control, PID control and so on. After selecting the appropriate control mode, it is also necessary to carry out static or dynamic identification according to the required control accuracy to ensure the stability and accuracy of the system.
二、 Minimum operating frequency The minimum operating frequency of the inverter determines the minimum speed of the motor. At low speeds, the heat dissipation performance of the motor is significantly reduced, and prolonged low-speed operation may lead to motor overheating or even burnout. In addition, the current in the cable increases during low-speed operation, which can also cause the cable to heat up. Setting the appropriate minimum operating frequency is the key to protect the motor and cable.
三、Maximum operating frequency Generally, the maximum frequency of the inverter is set to 60Hz, but some devices can reach more than 400Hz. A high frequency means that the motor will run at high speed, which may exceed the rated speed limit of its bearings for an ordinary motor, and it is questionable whether the motor's rotor can withstand this centrifugal force. Understanding and setting the maximum operating frequency correctly can effectively avoid equipment damage.
四、Carrier frequency The carrier frequency determines the switching speed of the inverter. The higher the setting, the greater the high harmonic component, which is closely related to the length of the cable, the motor and the heating of the cable. Appropriate carrier frequency setting can reduce electromagnetic interference and protect the normal operation of the equipment.
五、Motor parameters In the parameters of the frequency converter, the motor power, current, voltage, speed, maximum frequency and other basic parameters need to be accurately entered. These parameters can usually be obtained directly from the nameplate of the motor to ensure accurate input is the first step to avoid operational failure.
六、Frequency hopping Resonance may occur at certain frequency points, especially when the equipment is large; or in the control of the compressor, the compressor must be avoided when the compressor's wheezing point. Therefore, set the frequency hopping parameters to avoid these "dangerous" frequency, can effectively prevent equipment damage.
Synchronised control of multiple inverters When two or more inverters need to work synchronously, the parameter setting is particularly important. The following is a simple setting method:
1. Preparation Prepare two inverters, two wires and a power supply.
2. Wiring Define the two inverters as master and slave respectively. The 485A port of the master is connected to the 485A port of the slave, and the 485B port of the master is connected to the 485B port of the slave. If there is a third inverter, also connect its 485A and 485B ports to the corresponding ports of the master respectively, and so on for more inverters.
3. Parameter Setting Host parameter: only modify F05.00 to 6 (select free protocol communication), and F05.03 to 0 (host address).
Slave parameters: modify F01.00 to 04 (set communication given), F01.15 to 2 (communication start/stop), F05.00 to 06 (free protocol communication), F05.03 to 01 (slave address). If there is a third slave, the parameter settings are the same as for the second slave, but the F05.03 address cannot be repeated.
4. Starting and debugging Start the master and adjust the frequency at will, the frequency of the slave will change synchronously with the master.
The parameter setting of frequency converter is not only related to the normal operation of the equipment, but also directly affects the efficiency and life of the whole system. Master these "magic" like setting skills, you can easily deal with a variety of complex industrial control needs. Quickly collect this inverter parameter settings, let it become your industrial control field of "treasure book" it!
