Application of gektec inverter in Rewinder

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Application of geetec inverter in Rewinder

the purpose of rewinder is to rewind the paper rolls produced by paper machine (called the original electronic tensile testing machine, such as LDX ⑶ 00 universal material testing machine paper roll) in turn, and the paper is made into finished paper after rewinding. It is generally divided into three parts: rewinding, paper cutting and paper feeding

rewinding Division: that is, rewinding, including riding roller, master roller and slave roller. Three rollers fix the paper roll in the middle position. With the torque applied by the master-slave stick, the paper stick rotates to wind up the paper. The riding roller exerts a certain pressure on the top of the paper stick through the air cylinder. The master roll and the slave roll are arranged horizontally side by side

paper cutting division: cut the paper into various set widths, and then enter the rewinding division. It is composed of front arc roll, middle cutting roll, cutter and rear arc roll. The cutting roller and the cutter cooperate to complete the paper cutting, and the width of the paper cutting is completed by manually adjusting the cutter distance. The curved roller can unfold and flatten the paper, which will also bring errors to the equipment

paper feeding segment: that is, unwinding. Each paper feeding segment is composed of a paper feeding belt roller and a paper guide roller. The paper feeding roller drives this experimental machine uses hydraulic pressure to apply experimental force to move the belt, and then drives the paper feeding stick to unwind; The paper guide roller can flatten and guide the conveying of paper

II. Key points of system control

1. The rewinding section is a load jointly driven by two motors, so the linear speed of the two rods must be completely consistent, otherwise the paper rod and paper will be damaged after relative displacement; At the same time, it is also necessary to ensure the load distribution effect on the two rollers, otherwise the output of the two motors will be inconsistent, or even there will be a complete motor drive, and then overload and overcurrent will occur. Of course, if the motor power is inconsistent, the proportional output torque of the motor can also be guaranteed

2. The system is composed of several parts. In order to keep the line speed of the whole system consistent and form a synchronous system, we need to have high requirements for the speed accuracy and matching of each part, otherwise it will affect the flatness of paper winding, or even pull the paper

3. When multiple frequency converters work at the same time, due to the influence between them and the difference in power, it is likely to produce some frequency converter bus voltage is too high. Braking or bus sharing should be considered

III. synchronous control

when a transmission equipment is driven by two or more motors, it is necessary to distribute the load between the motors through synchronous control to achieve uniform balance, so as to meet the control accuracy of the transmission point. Working principle of synchronous control: the main engine is a typical speed control, while the secondary drive is a speed or torque control. Generally speaking, it can be divided into: when the motor shafts of the main drive and the secondary drive are fixedly and rigidly connected with each other through gears or chains, there can be no speed difference between the secondary drive and the main drive. The secondary drive uses torque control, which is only responsible for outputting a certain proportion of torque to reduce the load of the main drive, The speed control of the whole transmission is completed by the main transmission. The host adopts speed control mode; When the motor shafts of the master drive and the slave drive are flexibly connected through the transmission belt and other equipment, a slight speed difference is allowed between the slave drive and the master drive, and the slave drive uses speed control

IV. geetec frequency converter control scheme:

there are two motors in the rewinding division that jointly drive a paper stick. After understanding the process, we decided to adopt the unique load distribution function of gk800. The master roll operates in the speed mode as the main speed of the system. Because the master roll and the slave roll jointly drive the paper stick, the slave roll works in the torque mode and forms a synchronous system with the master roll. The torque signal of the master roll is output to the slave roll through the analog quantity as the torque setting, and the speed of the master roll is output to the slave roll as the speed limit

the most basic condition for the normal operation of the whole system is that the linear speed is consistent. Combined with the control characteristics of gk800 frequency converter, we adopt pulse train position control. The speed encoder signal of the master roll is sent to the following slave as a feedforward signal, and then the control of the position loop is introduced to make it fine tune on the basis of the feedforward speed, so as to complete the follow effect of the slave to the master. In order to improve the control accuracy, all motors are equipped with ABZ encoder, the frequency converter adopts gk800 series, all the frequency converters are powered by DC, and the encoder card is installed to complete the closed-loop vector control. The linear speed of the whole system comes from the speed of the main roll of the rewinding division, which can be determined by digital setting, analog setting (support -10v), communication setting, pulse setting and other ways. In 2016, 15 projects such as 4G evolution system, flexible composite robot and key parts were selected

v. gittec inverter control features

1. Load distribution

host speed mode, with PG vector control

frequency setting method: digital setting, analog setting (support -10v), communication setting, pulse setting

the output speed of the host is adjusted after the given frequency value and feedback value are calculated by the speed loop PI

slave torque mode, PG vector control

the given torque value comes from the analog output signal of the host torque, and the host speed signal is input to the rear of the slave as the speed limit of the slave

during operation, the master transmits the output torque to the slave as the given torque of the slave. The slave automatically adjusts its own speed according to the torque of the master to adapt to the torque of the master, achieve the balance between speed and torque, and automatically compensate the synchronization error caused by machinery

2. Pulse train position control:

control the operation mode of the motor encoder feedback pulse number following the command pulse number, as shown in the figure below. The position command setting mode in the figure is set through F, and the position feedback is the pulse signal input from the motor encoder

3. A variety of power supply options

gitec inverter supports AC and DC power supply (with buffer). This system adopts the mode of common DC bus, which improves the efficiency, increases the stability and eliminates the braking resistance

VI. conclusion

after simple debugging, the system runs very stably. The load distribution consistency of the master and slave rods of the rewinding section is high; The fluctuation of each speed segment of the vehicle's linear speed is very small, which fully meets the customer's process requirements, and the export has been completed

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