CN210683023U - Double-mechanism synchronous operation lifting control system for tower crane - Google Patents

Abstract

A double-mechanism synchronous operation lifting control system for a tower crane comprises a Programmable Logic Controller (PLC) and a control unit LFV-CU; two interchange converters, two braking units, two brake resistance, two inverter motor, encoder PG, two brakers and two absolute value encoders, the control unit takes two power unit drive bi-motors, realizes synchronous operation through vector control and load distribution to through adding the absolute value encoder on the mechanism, realize more accurate closed loop vector control. The adopted load distribution mode can lead the two motors to coordinate the output, and reduce the risk of mechanical vibration.

Description

Double-mechanism synchronous operation lifting control system for tower crane

Technical Field

The utility model belongs to the technical field of construction machinery equipment, a it plays to rise control system to relate to tower crane with double-mechanism synchronous operation.

Background

In the future, with the continuous development and diversification of engineering and building industries, new building forms such as large-scale electrical buildings, bridges and PCs are continuously developed. Large tower cranes are popular. On the premise of ensuring larger lifting capacity, the electrical control system and the form of electric traction need to have new breakthroughs. Therefore, the electric control system develops towards a novel and intelligent direction, and is a new direction for diversified development of the large electric traction tower crane.

Disclosure of Invention

The utility model provides a it plays to rise control system to relate to double-mechanism synchronous operation for tower crane takes two power unit drive bi-motors by the control unit, realizes synchronous operation through vector control and load distribution to through adding the absolute value encoder on the mechanism, realize more accurate closed loop vector control. The adopted load distribution mode can lead the two motors to coordinate the output, and reduce the risk of mechanical vibration.

The utility model adopts the technical scheme as follows:

a double-mechanism synchronous operation lifting control system for a tower crane comprises a Programmable Logic Controller (PLC) and a control unit LFV-CU; the system comprises two alternating-current frequency converters, two braking units, two braking resistors, two variable-frequency motors, two speed encoders, two brakes and two absolute value encoders; the programmable logic controller PLC and the two absolute value encoders are respectively connected with the control unit LFV-CU; the alternating current frequency converter LFV-A is connected with the brake unit BUA and the brake resistor RLA, and a variable frequency motor LM-A of the alternating current frequency converter LFV-A is communicated with the control unit LFV-CU through the brake LFaA. The alternating current frequency converter LFV-B is connected with the brake unit BUB and the brake resistor RLB, and a variable frequency motor LM-B of the alternating current frequency converter LFV-B is communicated with the control unit LFV-CU through the brake LFaB.

The Programmable Logic Controller (PLC) and the frequency converter can detect logic signal input, interlocking signals, operation of the frequency converter, zero speed and faults so as to enable the PLC and the frequency converter to execute corresponding actions;

the Programmable Logic Controller (PLC) realizes logic control through software programming;

two AC frequency converters are provided with speed feedback cards and form a PWM-vector control AC frequency conversion speed regulation system with two variable frequency motors provided with speed encoders, and the speed regulation ratio reaches 1: 100, respectively;

two reel sides of the control unit LFV-CU are respectively provided with an absolute value encoder, and a detection signal of the encoder is directly input into the frequency converter control unit; the mechanism operation is monitored and correspondingly processed through the input/output frequency of the frequency converter, the signal comparison of the motor encoder and the absolute value encoder of the winding drum;

the motor operates in a quadrant I, a quadrant II, a quadrant III and a quadrant IV, and when the motor operates in a speed reduction state, electric energy is released to the brake resistor through the brake unit.

The utility model discloses a system, Variable Frequency Speed Governing (VFSG) range is wide, the precision is high, the response is fast, go up and down steadily, the converter is accelerating with the speed reduction in-process, the rotational speed change of motor is according to the continuous stepless change of slash rule, the mechanical properties of motor is good, especially at low-speed operation process, also can export rated torque, level and smooth acceleration and deceleration and stable operation, make reduction drum and the transmission system in the mechanism not bear the impact force in work, and the frequency conversion speed governing (VFSG) system most component adopts contactless electrical components, can its fault rate of effectual reduction, thereby improve its mechanical life and electric life. A PLC (programmable logic controller) connected with the touch screen through Profinet; PLC and drive division are connected through high-speed Profinet communication, guarantee high ageing, with the help of 1: 1LED channel distribution, can quickly position errors on site, can quickly realize channel and diagnose the same programming debugging platform through programming software, HMI, WebServer and other ways without programming when faults occur, has general programs and strong expansibility,

drawings

Fig. 1 is a schematic structural diagram of the present invention.

In the figure: 1 programmable controller PLC; 2 control unit LFV-CU; 3-1 alternating current frequency converter LFV-A; 3-2 alternating current frequency converter LFV-B; 4-1 braking unit BUA; 4-2 braking unit BUB; 5-1 brake resistor RLA; 5-2 brake resistor RLB; 6-1 variable frequency motor LM-A; 6-2, variable frequency motor LM-B; 7-1 speed encoder PGA; 7-2 speed encoder PGB; 8-1 brake LFaA; 8-2 brake LFaB; 9-1 absolute value encoder PGA 1; 9-2 absolute value encoder PGB 1.

Detailed Description

The following detailed description of the embodiments of the invention refers to the accompanying drawings.

As shown in fig. 1, the system performs self-check after power supply, and the programmable logic controller PLC 1 and the frequency converter can detect signals such as logic signal input (such as a linkage table action command), linkage signal (such as a tower crane safety limit switch and a lifting load limit switch), operation of the frequency converter, zero speed and fault, so that the PLC and the frequency converter execute corresponding actions.

The Programmable Logic Controller (PLC) realizes logic control through software programming;

the two AC frequency converters (the AC frequency converter LFV-A3-1 and the AC frequency converter LFV-B3-2) are provided with a speed feedback card, and form an AC frequency conversion speed regulation system with PWM-vector control with two frequency conversion motors (a frequency conversion motor LM-A6-1 and a frequency conversion motor LM-B6-2) provided with speed encoders (a speed encoder PGA 7-1 and a speed encoder PGB 7-2), and the speed regulation ratio reaches 1: 100, respectively; the starting torque at zero speed can reach 150%, and the speed regulation precision is very high and reaches within +/-0.02%.

In addition, two reel sides of the control unit LFV-CU 2 are respectively provided with an absolute value encoder (absolute value encoder PGA 19-1 and absolute value encoder PGB 19-2), and a detection signal of this encoder is directly input to the inverter control unit. Through the signal comparison of the input/output frequency of the frequency converter, the motor encoder and the absolute value encoder of the winding drum, more accurate control can be realized, and safety faults such as hook slipping, overspeed and the like in the running process of the mechanism can be monitored and correspondingly processed.

The motor runs in a quadrant of one, two, three or four, and when the motor runs in a deceleration state, electric energy is released to the brake resistors (the brake resistor RLA 5-1 and the brake resistor RLB 5-2) through the brake units (the brake unit BUA 4-1 and the brake unit BUB 4-2). The working condition of the motor requires that the brakes (the brake LFaA 8-1 and the brake LFaB 8-2) work frequently, the system software ensures the accurate adjustment of logic control and time parameters, ensures that the frequency converter has enough output current before the motor brake is electrified and released, and cannot slide when the brake is released; meanwhile, after the brake is released, the motor is required to be started at zero speed, and the torque of the motor reaches 150% of a rated value, so that the motor can smoothly lift a heavy object; the software meets the design requirements of various safety devices of the hoisting mechanism, and improves the safety and reliability of the system; the control function of meeting the highest running speed of the motor in sections according to different hanging weights is achieved, and the working efficiency is greatly improved.

In addition, the system is provided with the touch screen, and the current working state of the tower crane, including information such as operating instructions, operating frequency and operating current, can be known at a glance through the touch screen. The micro-speed and fixed-distance operation of the lifting mechanism can be executed through the touch screen. The faults occurring in the system are described in the form of codes and words, so that the judgment and the elimination of the current faults are facilitated for operators and maintenance personnel. The screen can also be used for setting relevant parameters of the system so as to enable the running state of the system to be consistent with the current working condition.

Claims (1)

1. A double-mechanism synchronous operation lifting control system for a tower crane is characterized by comprising a Programmable Logic Controller (PLC) and a control unit LFV-CU; the system comprises two alternating-current frequency converters, two braking units, two braking resistors, two variable-frequency motors, two speed encoders, two brakes and two absolute value encoders;

the programmable logic controller PLC and the two absolute value encoders are respectively connected with the control unit LFV-CU; the alternating current frequency converter LFV-A is connected with the brake unit BUA and the brake resistor RLA, and a variable frequency motor LM-A of the alternating current frequency converter LFV-A is communicated with the control unit LFV-CU through the brake LFaA; the alternating current frequency converter LFV-B is connected with the brake unit BUB and the brake resistor RLB, and a variable frequency motor LM-B of the alternating current frequency converter LFV-B is communicated with the control unit LFV-CU through a brake LFaB;

the Programmable Logic Controller (PLC) and the frequency converter can detect logic signal input, interlocking signals, operation of the frequency converter, zero speed and faults so as to enable the PLC and the frequency converter to execute corresponding actions;

the Programmable Logic Controller (PLC) realizes logic control through software programming;

two AC frequency converters are provided with speed feedback cards and form a PWM-vector control AC frequency conversion speed regulation system with two variable frequency motors provided with speed encoders, and the speed regulation ratio reaches 1: 100, respectively;

two reel sides of the control unit LFV-CU are respectively provided with an absolute value encoder, and a detection signal of the encoder is directly input into the frequency converter control unit; the mechanism operation is monitored and correspondingly processed through the input/output frequency of the frequency converter, the signal comparison of the motor encoder and the absolute value encoder of the winding drum;

the motor operates in a quadrant I, a quadrant II, a quadrant III and a quadrant IV, and when the motor operates in a speed reduction state, electric energy is released to the brake resistor through the brake unit.

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