Application of the hottest delta inverter in cold

2022-07-27
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Application of delta inverter in cold rolling mill Abstract: This paper mainly describes the application of Delta V series inverter in direct torque control of cold rolling mill background: at present, in the cold rolling mill application industry, the cold rolling ribbed steel bar production line can be fully automated from setting out, steel bar rolling, strength control, extension control, cut to length, automatic leveling, two side blanking, and coil winding line. In these applications, direct torque control is required for the motor. Sometimes it is not possible or inconvenient to install an encoder to feed back the motor speed. Therefore, it is hoped that the frequency converter can realize torque control for the motor in the case of open-loop (no encoder feedback). Delta V series frequency converter has the function of open-loop torque control, which can just meet the requirements of some users

key words: Delta V series frequency converter, direct torque control, cold rolling mill

1. Preface:

the main product types of current cold rolling series equipment include: cold rolling torsion series equipment, straightener series equipment and cold rolling ribbed bar production series equipment. The cold-rolled ribbed steel bar equipment is a steel rolling production line, and the material is the original rolled steel bar. After treatment by the production line, the surface is embossed with ribs and cut by fixed length. First, it is stretched by the direct torque control of the primary motor, then it is stretched by the secondary motor and the surface is embossed, then it is stretched by the tertiary motor, and finally it is cut at the end of the production line. The primary motor was previously operated by the torque motor. Considering the many advantages of the frequency converter control, the frequency converter is used to replace it for torque control. In view of the space constraints of the production line, it is not suitable to install tension frame sensors between the primary and secondary motors for feedback, and the open-loop torque control of the V series frequency converter is required for direct drive

2. System architecture:

1) Jin min of the cold rolling equipment production line has developed a number of high-performance materials. The process is as follows:

rebar raw materials → vfd370v43a torque control (primary motor) → vfd550b43a speed control (secondary motor) → vfd055b43a speed control (tertiary motor) → fixed length cutting → completion

2) inverter configuration: one vfd370v43a, vfd550b43a and vfd055b43a respectively

3) vfd370v43a external electrical control part of frequency converter:

a, a potentiometer is connected to +10v, AVI and ACM to adjust the torque command

b. a button is used to switch the blameless speed/torque mode, and in the speed mode, this button realizes the terminal command of inching frequency at the same time

c, short circuit AVI and AUI terminals

d. short circuit MI1 and mi2 terminals

its external wiring diagram is as follows:

3. Process requirements:

in the production line process of cold rolling equipment, vfd370v43a, which is used to drive the primary motor (driven), carries out direct torque control, and pulls the reinforcement forward in the production process. The given torque is an appropriate value; When the secondary motor (active) runs, the primary motor will follow the secondary motor in the system to replace the torque motor previously used. And in the actual use process, when a roll of reinforcement is used up, it is required to realize inching operation feeding in the speed mode when replacing materials, so that the reinforcement can smoothly pass through the mechanical part of the equipment. In addition, vfd037v43a of frequency converter shall be able to drive its heavy load independently within the range of maximum torque command, for example, the load shall be replaced by the reinforcement with larger diameter

4. Commissioning steps:

1). Optimize the parameters of the primary motor and set the corresponding parameters:

=4 (torque control mode)

=2 (external analog quantity of frequency command)

=1 (AVI is the given frequency/torque command)

at this time, turn the external potentiometer and input a more appropriate torque for direct torque control. At this time, the reinforcement does not move forward under this torque. Only when the secondary stretching motor runs at the speed, the primary stretching motor drives the reinforcement to move forward under the torque mode

2). Realize inching operation under speed mode

when external terminal mi2 is switched to speed mode (=32 torque speed mode switching),

set external terminal MI1, =1 (multi-stage speed command I)= 1 (speed of the first section is 1Hz)

at this time, the multi-stage speed frequency 1 can operate normally in the speed mode. With the load, the effect is also good

3). In the direct torque mode, test whether it can drive a larger load. Measure with a dial indicator according to the two force columns.

due to the different thickness of reinforcement materials, after increasing the load, when the motor directly gives torque, gradually turn the potentiometer to increase the torque command, and observe the reaction of the motor. To observe whether the load can be pulled before the torque increases to full torque. The setting parameters are as follows: =250 (the torque limit is set to 250%)

when the potentiometer is rotated to the full position, the torque command is the maximum value, but the load does not move; Set =8 (AUI analog function is torque compensation); The effect is not good when AUI analog quantity is adjusted separately, and it is effective when AVI and AUI analog quantity are adjusted at the same time. Because only one potentiometer analog quantity input is allowed in the external circuit, the AUI and avi terminals are short circuited. When the external potentiometer rotates, the torque. However, at present, the outside world can not help but admit that the command and torque compensation are gradually increasing. When it increases to a certain value, the primary motor drives the load to run

4)、 Parameter setting:

the final parameter setting of vfd370v43a, which controls the primary motor, is as follows:

=4 the control mode is torque control

=2 the frequency is specified from the external analog input

=50 the maximum operating frequency is 50Hz

=50 the rated frequency of the motor is 50Hz

=380 the rated voltage of the motor is 380V

=1 the multi-function input terminal MI1 is multi-stage speed command I

=32 the function input terminal mi2 is torque speed mode switching

=1 Analog avi input is frequency/torque command

=8 analog AUI input is torque compensation

=1 the first section speed is 1Hz

=16.9 the motor no-load current is 16.9a

=151.8 the motor R1 is 151.8m Ω

=166 the motor R2 is 166m Ω

=471.8 the motor LM parameter is 471.8mh

=29.9 the motor LC parameter is 29.9mh

=200 oscillation compensation factor 200

=250 torque limit 250%

5. Commissioning summary:

1 Delta inverter uses direct torque mode instead of torque motor, which has superior performance and good effect

2. The production line runs stably and the maintenance cost is greatly reduced

3. The quality of the produced products is very good, and the end-users respond well

6. The site drawings are as follows:

Figure 1: the lower right corner is the primary stretching motor (running direction left, driven)

Figure 2: the lower left corner is the secondary stretching motor (direction right, active)

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