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A Control Method of Variable Arm Crane Using Vector Variable Voltage and Frequency Converter as Power Supply

A technology of variable voltage, variable frequency, and control method, which is applied to cranes, load hanging components, transportation and packaging, etc., and can solve problems such as difficult installation, inaccurate results, and lack of automatic safety control

Inactive Publication Date: 2016-08-24
CHENGDU QIANQIU TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Since all the sensors are installed externally, hardware cost, installation method, and measurement accuracy have brought a series of problems; there are obvious sensor additional hardware costs are high, installation is difficult, and measurement is greatly affected by the installation location and method. Many disadvantages that cause measurement difficulties, inaccurate results and lack of automatic safety control

Method used

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  • A Control Method of Variable Arm Crane Using Vector Variable Voltage and Frequency Converter as Power Supply
  • A Control Method of Variable Arm Crane Using Vector Variable Voltage and Frequency Converter as Power Supply
  • A Control Method of Variable Arm Crane Using Vector Variable Voltage and Frequency Converter as Power Supply

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Experimental program
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Effect test

Embodiment 1

[0137] The crane parameter of present embodiment is as figure 1 figure 2 shown.

[0138] A control method for a variable arm crane using a vector variable voltage variable frequency (VT-VVVF hereinafter the same) frequency converter as a power source, comprising the following steps:

[0139] S1, the hoisting motor vector inverter controls the hoisting motor to start running at the starting frequency fqd;

[0140] S2. After the hoisting motor starts, gradually increase the output frequency of the inverter to the measurement frequency f (principle: ensure no overload and stable hoisting at as low a frequency as possible, f=15Hz in this example); measure the frequency conversion of the hoisting motor VT-VVVF rectifier output DC voltage U d and DC current I d , which corresponds to the DC power

[0141] P d =U d × I d When the fluctuation range is less than 5% within 1 second, measure and record its value P d =U d × I d and the output frequency f, calculate the output ...

Embodiment 2

[0216] The crane parameter of present embodiment is as figure 1 figure 2 shown.

[0217] The control method of the variable arm crane using the vector variable voltage variable frequency frequency converter as the power supply of the present embodiment includes the following steps: the system operating condition parameters of the present embodiment are the same as those of the embodiment 1:

[0218] S1, the hoisting motor vector inverter controls the hoisting motor to run and start at the starting frequency fqd;

[0219] S2: When the rectified output DC power of the inverter fluctuates less than 10% within 2 seconds, then detect and record the rectified output DC power of the vector variable-voltage variable-frequency inverter is 34.57kW, and the output frequency of the vector variable-voltage variable-frequency inverter is f=15Hz.

[0220] Then Tfz=Kdj×Kdx×Kjs×P d / f

[0221] =664.8×0.8075×118.4×34.57 / 15=146485.07N m;

[0222] Known from the above table: Tfz=146485.07N ...

Embodiment 3

[0279] The system operation condition parameter of the present embodiment is the same as embodiment 1: the crane parameter such as figure 1 figure 2 shown.

[0280] The difference between this embodiment and Embodiment 2 is that the slip rate of the hoisting motor adopts the corrected slip rate,

[0281] The rated slip rate S without repair n calculate:

[0282] S n =(n 0 -n N ) / n 0 =(750-722) / 750=0.0373

[0283] Corrected slip: by formula (3-5):

[0284]

[0285] ∴S=0.0373x0.95x(34.57 / 110)x(50 / 15)=0.0373x0.9952=0.03712;

[0286] Using the corrected slip S to calculate the output speed of the hoisting motor is: n N =n 0 -S×n 0 =750-750x0.03712=722.16r / min. During the actual measurement, the hoisting motor rotates at 723r / min. Using the corrected slip rate S is better than using the uncorrected rated slip rate S n The error between calculating the output speed of the lifting motor and the actual measured speed is smaller; it can be concluded that using the fo...

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Abstract

The invention specifically relates to a control method for a force-variable jib crane using a vector voltage-variable frequency-variable frequency converter as a power supply, belonging to the field of crane control. The control method provided by the invention comprises the following steps: indirectly measuring the load torque of a lifted heavy matter through measuring of direct current power and output frequency of the frequency inverter, and using the measured load torque and the rated power of a lifting motor as limited conditions so as to obtain maximum operating frequency of the lifting motor; and determining the operating frequency of the lifting motor by coaction of speed control gears, a crane jib and safe load torque. The control method in the invention enables a crane system to work in a rated torque and a rated power, thereby achieving the dual purposes of ensuring safety and improving efficiency; meanwhile, the lifting load torque of the crane is less than or equal to the safe load torque, so the crane cannot overturn. According to the invention, through measuring of intrinsic parameters of the frequency inverter, the number of sensors in a traditional crane is reduced, measuring accuracy is improved, and system complexity and cost are lowered; thus, the crane system is simpler, more precise and more efficient and has higher reliability.

Description

technical field [0001] The invention belongs to the field of crane control, and in particular relates to a control method of a variable force arm crane using a vector variable voltage variable frequency frequency converter as a power supply. Background technique [0002] With the advancement of technology and the improvement of market requirements, in recent years, more and more frequency conversion technology has been introduced into the crane system. Low cost, high degree of integration and other advantages, has gradually become the most important power source of the crane system. Crane is a kind of mechanical equipment commonly used in modern production. Different use occasions have different use requirements, and cranes that can adapt to these occasions will be designed and manufactured for different use occasions. Some cranes only lift or lower heavy loads. In addition to driving the weight up or down, the other part of the crane will also drive the weight to make a ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B66C13/22B66C23/88
CPCB66C13/22B66C23/88B66C2700/03
Inventor 聂剑王友军税蔚栋高良儒唐莉王毅
Owner CHENGDU QIANQIU TECH
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