Most of the domestic metal processing companies that use wire drawing machines are not unfamiliar with frequency converters. This is because they have been widely used in wire drawing machinery long ago, but most of them are configured by foreign brands. The reason for the frequency converter is that the development and marketing of the domestic frequency conversion speed control technology started late, and it lags behind foreign inverter products in a period of time, regardless of the advanced nature of the software control algorithm or the stability of the hardware platform. There is a certain gap.
After more than ten years of development, the domestic inverter industry has made considerable progress in technology and marketing. The products developed by the company can also meet the needs of most industrial sites. In accordance with the application characteristics of wire drawing machinery, INVT series inverter independently developed by Shenzhen Inventronics Co., Ltd. integrates vector control technology (VC, SVC), torque control technology, and V/F control technology. At the same time, the design is convenient. The synchronous control function and the tension control function used in the take-up line completely solve the control requirements of the wire drawing machine, thereby breaking the situation in which the imported brands dominate the world.
Drawing machine technology
Drawing machine, also known as drafting machine. From the product terminal, the drawing machine can be divided into large drawing machine, middle drawing machine, small drawing machine, and micro drawing machine. From the drawing machine internal control mode and mechanical structure, it can be divided into water tank type, pulley type, Straight forward and other major types. For different requirements, different accuracy of the rules of the product, different metal materials, choose different specifications of the drawing machine. For wire and cable manufacturers, the double-frequency-controlled fine-drawing machine is widely used. Relatively speaking, the required control performance is also relatively low. For most wire-line manufacturers, their accuracy requirements and pull-out stability are based on the material properties. High, so more straight-line drawing machines are used. Although the drawing process is different, the work process is basically the same (as shown below):
â— Take-off line: For the entire wire drawing machine, the control of the wire drawing machine is not excessively precise. Most wire drawing machines and pay-off operations are realized through the inverter-driven pay-off rack, but there are also some Dual-frequency control drawing machine, even directly through the wire drawing tension drawing wire drawing machine, to achieve free play;
â— Drawing: Drawing is the most important part of the drawing machine. Different metal materials, different types of silk products and requirements, drawing links are very different, the article will be described in detail behind the water tank type wire drawing machine and straight wire drawing machine specific operation process;
â— Take-up: The working speed of the take-up link determines the production efficiency of the entire wire drawing machine and is the most difficult part of the entire system. In the take-up part, commonly used control technologies include synchronous control and tension control to realize the winding of metal products;
Below, we will introduce the application of our company's products in the drawing machine industry with the example of dual-frequency control water tank type wire drawing machine and multi frequency conversion synchronous control straight wire drawing machine.
1, Jiangsu drawing machine factory pull machine double frequency control
1.1 System main parameters
Process parameters
Motor parameters
Inlet diameter (mm)
1.1
Hosts
3.7KW/6 pole
Outlet diameter (mm)
0.3 to 0.35
Winding
1.5KW/4 pole
1.2 Fine pull machine
Dual frequency control principle
The system is a tower wheel type water tank drawing machine. The tower wheel type water tank drawing machine, through the speed ratio of the tower wheel, gradually stretches the metal wire and allows the wire to slide within the tower wheel. Therefore, the processed metal wire must have good toughness. This wire drawing machine is widely used in the processing of copper wire. The host uses CHE100 open-loop vector inverter (CHE100-004G/5R5P-4) and the rewinding uses CHF100 high-performance V/F control inverter (CHF100-1R5G-4). The two motors use the same operating signal K1, and a switch signal K2 is connected in parallel to the winding operation signal. Because the deceleration time of the main engine is long (30s), the deceleration time of winding is very short (0.1s). It is ensured that when there is a stop command, the winding inverter can still operate normally. The parallel operation signal K2 is controlled by the collector output Y of the host to control an intermediate relay. The electrical schematic is shown in Figure 2:
1.3 Speed ​​Synchronization Control
The main control operation switch K1 controls the host to start and stop. The traction and tension level inverter controls the running speed of the whole system. The potentiometer on the control panel sends the host drawing speed signal. This analog voltage signal (0~10V) is input to the main inverter of the drawing machine through the AI1 port as its frequency setting. , Determine the total speed of the stretcher. At the same time, the running frequency of the drawing main frequency converter is output to the winding inverter (AI2) through the analog quantity (AO), and is used as the wind speed synchronous synchronization given for the winding frequency converter. Note that for the winding frequency converter, the corresponding operating frequency should be equal to the operating frequency when the winding wheel diameter is the maximum. The output frequency of the coil-level inverter follows the change of the operating frequency of the wire-drawing inverter. Considering the mechanical characteristics of the equipment and the certain speed requirements, the host acceleration/deceleration time is set to 30s, and the acceleration/deceleration time of the winding inverter is set to 0.1s.
A tensile pendulum rod is installed between the wire drawing end and the wire drawing end to detect the tension of the output wire. As a tension feedback signal of the wire drawing, the feedback frequency is input to the winding inverter, and the winding frequency inverter uses the internal PID as the feedback amount. After calculations and various compensations, the current synchronization speed (analog AI2 input) of the winding is superimposed, and the output frequency of the inverter is adjusted so as to control the winding motor speed to synchronize with the wire drawing speed of the wire drawing machine, and at the same time, the wire rod is also used. The tension is kept constant.
1.4 Inverter main function parameter setting
1.4.1 Host Inverter (CHE100-004G/5R5P-4)
P0.01:1 terminal command channel;
P0.03:1 AI1 given;
P0.08:30 acceleration time;
P0.09:30 deceleration time;
P6.00:1 is running in progress;
P6.01:3 fault output;
1.4.2 Winding-up Converter (CHF100-1R5G-4)
P0.03:1 External terminal operation
P0.07:0.1 Acceleration time
P0.08:0.1 deceleration time
P3.01:6 PID Control
P3.02: 1 AI2 setting
P3.04: 2 A+B
P5.17:43 AI2 upper limit corresponding setting
P9.01:50 PID given value
P9.03:1 PID is an inverse characteristic
P9.04:10 Proportional Gain
P9.05:1.0 integration time
For other details, refer to "CHE Series Vector Inverter Specifications" and "CHF General Inverter Specifications".
2. Frequency conversion control of a straight drawing machine of a drawing machine factory in Hangzhou
2.1 Brief introduction of straight-type wire drawing machine
In the production and processing of metal products, straight-feed wire drawing machines are the most commonly used manufacturing equipment. Motors and torque motors were commonly used in the past. However, the control flexibility, automation, and energy consumption are traditional. The control methods are increasingly not suited to the development of the industry. With the extensive promotion of control technology and variable frequency speed control technology, variable frequency control began to be used in a large number of in-line wire drawing machines. The system can use PLC to achieve functions such as wire drawing speed, variety setting, closed-loop process control, and fixed-length control.
The in-line drawing machine is a multi-stretching machine that stretches the wire at the same time, and the work efficiency is high. Because the characteristics of stainless steel wire are brittle and do not allow the steel wire to slide in the mold, it is easy to break during the drawing process. Therefore, the wire speed is strictly required to be synchronized at all stages of the mold, so that the motor at all levels Synchronous control performance, speed steady-state accuracy, and the speed of the dynamic response of the motor have higher requirements.
2.2 Description of the control system
A drawing machine factory in Hangzhou, a professional straight-line drawing machine manufacturer. The schematic diagram of simple electrical control is as follows. This system uses five CHV100-015G-4 high-performance vector inverters to achieve the transmission control of the tension part. One CHV100-7R5G-4 high-performance inverter is equipped with a tension control card for winding control. Each arm is equipped with a swing arm in front of it. The position sensor can detect the position of the swing arm to detect the tension of the wire. The signal (0~10V) is used as the PID feedback. All six motors use variable frequency asynchronous motors with mechanical brakes. The logic control of the drawing machine system is relatively complicated, and there are differences in the process, and each cascade is controlled by the PLC. Synchronization control is controlled by the inverter. The working principle is: according to the operator's panel setting and determining the speed of the operation, the analog signal of the speed enters the PLC. After the PLC considers the time of acceleration and deceleration, it outputs it according to a certain slope. Analog signal. The purpose of doing so is mainly to meet the needs of some operations such as inching and threading. The analog voltage signal output from the PLC is simultaneously connected to the AI2 input of all inverters and used as the main reference signal of the frequency. The signal of each swing arm position sensor is connected to the corresponding mode inverter as the feedback signal of PID control. According to the position of the swing arm in the middle, set a given value of PID. This system is a very typical PID control system with feed-forward. It is connected one level at a time. PID is superimposed on the fine adjustment and main reference.
The stable condition of this drawing system depends to a large extent on the speed of PID action, the precision of the speed control of the motor controlled by the inverter, and the response speed of the output torque. In order to improve the steady-state accuracy of the motor running speed, it is also used in many cases. PG vector control technology (infinity's CHV100 series inverter's PG vector control steady-state accuracy up to 1/1000) to adjust the speed of the stretch motor, so the parameters must be set carefully, at low speed, medium speed Speed, speed, and acceleration and deceleration speeds need to be considered.
In addition, the winding part is realized by a special module for tension control of CHV100. The winding speed is provided by the last-level (fifth-order) model-track control inverter, which is used as the linear velocity signal for calculating the diameter of the coil. The tension of the system can be set by the potentiometer. The winding-level inverter adopts torque control. The encoder needs to be installed on the shaft of the winding motor. The encoder is connected to the built-in PG card of CHV100 and used as the acquisition input of the motor speed.
The control principle is as follows:
With the current line speed of the winding (analog AI2 input), the curl diameter of the current winding is calculated.
The calculation equation is as follows: D = (i × N × V) / (π × f)
Where i mechanical transmission ratio N motor pole pair number V linear velocity f current matching frequency
The output torque of the inverter is calculated from the set tension and the roll diameter of the drum (obtained by the roll diameter calculation module).
The calculation equation is: T = (F × D) / (2 × i)
Among them: T inverter output torque F tension setting
D rotary diameter i mechanical transmission ratio
In order to control the output torque of the motor to reach the constant tension F on the wire.
In the special module of tension control for CHV100, the compensation of the moment of inertia has been added, which can well solve the phenomenon of unstable tension caused by overcoming the system inertia during the acceleration and deceleration of the tension control system.
When the entire wire drawing system was started, six frequency converters started at the same time, and the linear speed was gradually adjusted to accelerate the system and eventually reach the required line speed.
2.3 Main parameters of the inverter
2.3.1 wire drawing converter
P0.01 1: terminal command channel
P0.03 6: PID control setting
P0.04 0: Analog AI2 setting
P0.06 2:A+B
P9.00 0: Keyboard given
P9.02 0: Analog channel AI1 feedback
P0.03 Set according to the actual situation
P0.04 set according to the actual situation
P0.05 set according to the actual situation
P0.06 Setting according to actual conditions The sampling period T (P0.07), PID control deviation limit (P0.08), and PID output buffer time (P0.08) are all set according to actual conditions.
2.3.2 winding converter
P0.00 1: With PG vector control
P0.01 1: terminal command channel
P1.08 1: Free Parking
P3.10 PG parameters (number of encoder lines, based on actual conditions)
P5.02 1:S1 terminal function selection: Forward operation
PF.00 1: Tension-free feedback torque control
PF.01 0: Rewind mode
PF.04 maximum tension setting (according to the actual situation)
PF.05 1: Analog AI1 as tension setting
PF.11 mechanical transmission ratio (according to the actual situation)
PF.12 maximum curl diameter
PF.14 Reel diameter
PF.18 0: Calculation of Reel Size by Linear Velocity Method
PF.22 maximum line speed (according to the actual situation)
PF.23 2: Analog AI2 as line speed setting source
PF.33 system inertia compensation coefficient (according to actual conditions)
For details, refer to the "CHV Vector Drive Instruction Manual" and "CHV Tension Control Function Instruction Manual."
to sum up
In the control of the wire drawing machine, the electrical control system composed of Inventronics inverter has a simple structure and clear logic, and the cost is still lower than the original one. Moreover, in terms of drawing process and energy saving, it is a very good solution. . Practice has proved that the above two control schemes can control the water tank type wire drawing machine and the straight type wire drawing machine separately, and can fully meet the technological requirements on the synchronous and constant tension take-up control.
Personal Care,Calf Massage Gun,Smart Neck Massager,Massager Fascia Massage Gun
Shenzhen Unitepin Tech Co.Ltd , https://www.rifnylife.com