How to set the parameters of the inverter to control multiple motors synchronously?

To know how to set the parameters of the frequency converter, you must first understand what the frequency converter is and what it is used for.

The frequency converter is a power supply device used to adjust the speed of asynchronous motors. According to the formula of speed n=60f/p(1-s), the frequency converter is essentially a voltage source with adjustable output frequency, which changes the motor speed by changing the power supply frequency.

While the frequency is changing, in order to avoid flux saturation and motor overheating, the voltage must also be changed, that is, to keep the V/F ratio constant. Therefore, the parameter settings of the inverter are all based on this core.

The inverter has many setting parameters, and each parameter has a certain selection range. During use, it is often encountered that the inverter cannot work normally due to improper setting of individual parameters. Therefore, the relevant parameters must be set correctly.

1. Control method

That is, speed control, torque control, PID control or other methods. After the control method is adopted, static or dynamic identification is generally performed according to the control accuracy.

2. Minimum operating frequency

That is, the minimum speed of the motor. When the motor runs at a low speed, its heat dissipation performance is very poor. If the motor runs at a low speed for a long time, it will cause the motor to burn out. Moreover, at a low speed, the current in the cable will increase, which will also cause the cable to heat up.

3. Maximum operating frequency

The maximum frequency of a general frequency converter is 60Hz, and some even reach 400Hz. The high frequency will make the motor run at high speed. For ordinary motors, their bearings cannot run at a speed exceeding the rated speed for a long time. Whether the motor's rotor can withstand such centrifugal force.

4. Carrier frequency

The higher the carrier frequency is set, the greater the high-order harmonic components are. This is closely related to factors such as cable length, motor heating, cable heating, and inverter heating.

5. Motor parameters

The inverter sets the motor's power, current, voltage, speed, and maximum frequency in the parameters, which can be directly obtained from the motor nameplate.

6. Frequency Hopping

At a certain frequency point, resonance may occur, especially when the entire device is relatively high; when controlling the compressor, the surge point of the compressor should be avoided.

Method for setting parameters of two or more inverters for synchronous control:

first step

Prepare two inverters, two wires, and a power supply.

Step 2

Inverter wiring, define two inverters as the master and slave respectively, connect the 485A port of the master to the 485A port of the slave, and connect the 485B port of the master to the 485B port of the slave. If there is a third inverter, connect the 485A and 485B of the third inverter to the 485A and 485B ports of the master, and so on if there are more.

Step 3

Inverter parameter setting. The host parameter only needs to change F05.00 to 6 to select free protocol communication. F05.03 is changed to 0 for the host address. The slave parameter needs to change F01.00 to 04 to set the communication setting; F01.15 is changed to 2 for communication start and stop, F05.00 is changed to 06 free protocol communication, and F05.03 is changed to 01 slave address. If there is a third slave, the parameters are the same as the second slave, but the F05.03 address cannot be the same as the second slave.

Step 4

Start the master, adjust the frequency at will, and the slave frequency will change with the master.