CN214585937U - Welding current monitor calibrating device - Google Patents
Welding current monitor calibrating device Download PDFInfo
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- CN214585937U CN214585937U CN202120781517.4U CN202120781517U CN214585937U CN 214585937 U CN214585937 U CN 214585937U CN 202120781517 U CN202120781517 U CN 202120781517U CN 214585937 U CN214585937 U CN 214585937U
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Abstract
The utility model discloses a welding current monitor calibrating device, the device includes VFD keyboard, programme-controlled standard signal source, AC/DC voltage power amplification module, DC current power amplification module, BTL AC current power amplification module, hollow coil, AC/DC current transformer and welding current monitor; the output end of the VFD keyboard is connected with a program-controlled standard signal source, the output end of the program-controlled standard signal source is connected with the signal input end of an AC/DC voltage power amplification module, and the output end of the AC/DC voltage power amplification module is connected with a welding current monitor; the output end of the alternating current-direct current voltage power amplification module is also connected with the feedback input end of the alternating current-direct current voltage power amplification module. The utility model discloses can export standard analog signal such as welding voltage, welding current, welding duration fast, promote the efficiency of welding current monitor calibration work.
Description
Technical Field
The utility model relates to a welding current monitor especially relates to a welding current monitor calibrating device.
Background
The welding process technology is widely applied to various industrial fields of industrial production, and the control of main welding parameters such as current, voltage and time is very important to the welding process and the welding quality; in order to ensure the manufacturing quality, welding current monitors are continuously available on the market, and the welding current monitors are widely applied to welding monitoring work in the industrial field and applied to the safe driving and protection navigation for the industrial manufacturing accurate welding technology.
Therefore, the accuracy of the welding flow monitor and the effectiveness of the monitoring index are the premise of effectively ensuring the welding process quality; however, no accurate standard device of the integrated welding current monitor is available in the market at present; especially, the detection and calibration of the number of peaks does not form an effective means for carrying out regular calibration, the conventional method for detecting the number of peaks and time usually adopts a mode of outputting a current signal for a short time by short-circuiting a load coil through a manual short-circuit switch after a certain current is passed so as to lose the current, however, the mode cannot effectively and accurately output the frequency of the current signal, and thus whether the detection of the number of peaks of the welding current monitor is correct cannot be accurately judged.
The welding current monitor mainly uses a Rogowski coil as a main part, and in order to obtain output with a large ampere-turn ratio, a multi-turn hollow coil needs to be wound for detection, so that the effect of realizing the output with the large ampere-turn ratio by small current is achieved. Because the characteristics of the air-core coil are that the alternating current impedance and the direct current impedance are different, the more the number of turns, the larger the phase difference is, and therefore the alternating current and the direct current cannot be completed on one device. Because the number of turns increases and the ac impedance increases, a high ac output voltage is required to obtain a designed current value, and the conventional power amplifier cannot meet the use requirement.
In the past, due to the sampling technology, mutual inductance sampling cannot be achieved in the same way of alternating current and direct current, and therefore two sets of sampling circuits need to be manufactured, so that the current and the voltage can only be calibrated in the calibration of a welding current monitor at present, two sets of devices need to be used for detecting alternating current and direct current respectively, and the number of welding peaks and time cannot be accurately detected and calibrated. Often, a plurality of processes are needed for calibrating one welding flow monitor to carry out detection and calibration for multiple times, so that long calibration time is needed, and the calibration work efficiency is low.
SUMMERY OF THE UTILITY MODEL
An object of the utility model is to overcome prior art not enough, provide a welding current monitor calibrating device, can export standard model signals such as welding voltage, welding current, welding duration fast, promote the efficiency of welding current monitor calibration work.
The purpose of the utility model is realized through the following technical scheme: a welding current monitor calibrating device comprises a VFD keyboard, a program-controlled standard signal source, an AC/DC voltage power amplification module, a DC current power amplification module, a BTL AC current power amplification module, a hollow coil, an AC/DC current transformer and a welding current monitor;
the output end of the VFD keyboard is connected with a program-controlled standard signal source, the output end of the program-controlled standard signal source is connected with the signal input end of an AC/DC voltage power amplification module, and the output end of the AC/DC voltage power amplification module is connected with a welding current monitor; the output end of the AC/DC voltage power amplification module is also connected with the feedback input end of the AC/DC voltage power amplification module;
the signal input end of the direct current power amplification module is connected with the output end of the program control standard signal source through a switch K1, and the output end of the direct current power amplification module is connected with the hollow coil through a switch K3;
the signal input end of the BTL alternating current power amplification module is connected with the output end of the program control standard signal source through a switch K2, and the output end of the BTL alternating current power amplification module is connected with the hollow coil through a switch K4;
the alternating current and direct current transformer is used for detecting the hollow coil, and the output end of the alternating current and direct current transformer is connected to the feedback signal input ends of the direct current power amplification module and the BTL alternating current power amplification module through a change-over switch K5.
The utility model has the advantages that: (1) the utility model can calibrate parameters such as voltage, current, wave peak number and time of the welding current monitor rapidly and accurately, and measure main detection parameters of the welding current monitor rapidly and accurately by the integrated design of the AC/DC power amplifier and the introduction of the standard power source technology, thereby improving the calibration work efficiency; and the measurement technical parameters can be effectively traced and calibrated.
(2) The utility model discloses a digital signal source control is used, and the calibration of welding current monitor crest number and time has been ensured to the cycle number that can accurate output sinusoidal signal.
(3) The utility model discloses a BTL (bridging) power amplifier application technique has obtained the high-voltage output problem of low pressure power supply, because positive negative power supply exports simultaneously because positive negative half cycle enlargies simultaneously, compares only with using positive power supply or negative power supply to compare at the same moment of only power amplifier, has promoted the power utilization efficiency.
Drawings
FIG. 1 is a schematic diagram of the device of the present invention;
FIG. 2 is a schematic diagram of a programmable standard signal source;
FIG. 3 is a schematic diagram of an AC/DC voltage power amplifying module;
FIG. 4 is a schematic diagram of a BTL AC power amplifier module;
fig. 5 is a schematic diagram of a level conversion circuit.
Detailed Description
The technical solution of the present invention is described in further detail below with reference to the accompanying drawings, but the scope of the present invention is not limited to the following description.
As shown in fig. 1, a calibration device for a welding current monitor comprises a VFD keyboard, a programmable standard signal source, an ac/dc voltage power amplification module, a dc current power amplification module, a BTL ac current power amplification module, an air-core coil, an ac/dc current transformer and a welding current monitor;
the output end of the VFD keyboard is connected with a program-controlled standard signal source, the output end of the program-controlled standard signal source is connected with the signal input end of an AC/DC voltage power amplification module, and the output end of the AC/DC voltage power amplification module is connected with a welding current monitor; the output end of the AC/DC voltage power amplification module is also connected with the feedback input end of the AC/DC voltage power amplification module;
the signal input end of the direct current power amplification module is connected with the output end of the program control standard signal source through a switch K1, and the output end of the direct current power amplification module is connected with the hollow coil through a switch K3;
the signal input end of the BTL alternating current power amplification module is connected with the output end of the program control standard signal source through a switch K2, and the output end of the BTL alternating current power amplification module is connected with the hollow coil through a switch K4;
the alternating current and direct current transformer is used for detecting the hollow coil, and the output end of the alternating current and direct current transformer is connected to the feedback signal input ends of the direct current power amplification module and the BTL alternating current power amplification module through a change-over switch K5.
In the embodiment of the application, the VFD keyboard is used for providing a man-machine interaction way, the set parameters are quickly input through the digital keyboard and are automatically transmitted to the program-controlled standard voltage source, and the problem that the backward operation mode of manually adjusting the voltage regulator is solved; the welding current monitor is connected with a Rogowski coil. The change-over switch K5 is a single-pole double-throw switch, the moving end of the change-over switch K5 is connected with the output end of the alternating current and direct current transformer, the first moving end of the change-over switch K5 is connected with the feedback signal input end of the direct current power amplification module, and the second moving end of the change-over switch K5 is connected with the feedback signal input end of the BTL alternating current power amplification module.
As shown in fig. 2, the program-controlled standard signal source includes an ARM micro-controller, a CPLD chip, a first DAC module, a second DAC module, and a crystal oscillator; the output end of the crystal oscillator is respectively connected with the ARM micro-control processor and the CPLD chip and is used for providing a clock reference for the ARM micro-control processor and the CPLD chip; the input end of the ARM micro-control processor is connected with the VFD keyboard, the output end of the ARM micro-control processor is respectively connected with the first DAC module and the second DAC module through the CPLD chip, the output end of the first DAC module is connected with the alternating current-direct current voltage power amplification module, and the output end of the second DAC module is respectively connected with the switch K1 and the switch K2.
The program control standard signal source is used for generating a 50Hz low-distortion periodic sinusoidal signal or a direct-current pulse square wave signal, and the time accuracy is ensured by using a high-precision crystal oscillator with temperature compensation; the second DAC module is used for carrying out DA conversion on the voltage signal, and the second DAC module is used for carrying out DA conversion on the current signal.
As shown in fig. 3, the ac/dc voltage power amplification module includes a first PID adjusting circuit and an ac/dc voltage power amplifier, the signal input terminal of the first PID adjusting circuit is connected to the program-controlled standard signal source, the output terminal of the first PID adjusting circuit is connected to the ac/dc voltage power amplifier, the output terminal of the ac/dc voltage power amplifier is connected to the welding current monitor, and the output terminal of the ac/dc voltage power amplifier is further connected to the feedback input terminal of the first PID adjusting circuit. The module is used for amplifying the power of an alternating current periodic voltage signal or a direct current pulse voltage signal sent by a standard signal source, and then synchronously sending the voltage signal and the current after the power amplification to a welding current monitor to provide a voltage reference signal. The voltage output signal is fed back to the PID input end through the precision resistor to be compared with the standard voltage signal, and automatic correction is carried out.
In an embodiment of the present application, the dc power amplifying module includes a second PID adjusting circuit and a dc power amplifier, an input end of the second PID adjusting circuit is connected to the program control signal source through a switch K1, and a feedback input end of the second PID adjusting circuit is connected to a first moving end of a switch K5; the output end of the second PID regulating circuit is connected with a direct current power amplifier, and the output end of the direct current power amplifier comprises an IH end and an OV end;
the switch K3 includes two sub-switches that are synchronously opened and closed, wherein the IH terminal is connected to the first terminal of the air core coil through the first sub-switch of the switch K3, and the OV terminal is connected to the second terminal of the air core coil through the second sub-switch of the switch K3.
The direct current power amplification module is used for amplifying the power of a direct current pulse current signal sent by a standard signal source, then sending the current signal after power amplification and voltage to the hollow coil synchronously, and obtaining the direct current signal through monitoring of the welding current monitor through the Rogowski coil to display the numerical value. The current output signal flowing through the hollow coil is sampled and fed back by the precision AC/DC current transformer and then sent to the PID input end to be compared with the standard current signal, and then is automatically corrected.
As shown in fig. 4, the BTL ac current power amplification module is configured to perform forward and reverse conversion on an ac periodic signal sent from a standard signal source, send the obtained signals with the same amplitude and the same phase and opposite phase to a forward and reverse power amplifier for power amplification, send the current signal after the forward power amplification and the voltage to the high end of the air-core coil synchronously, send the current signal after the reverse power amplification and the voltage to the low end of the air-core coil synchronously, and obtain an ac current signal through the welding current monitor through the rogowski coil for numerical display. The circuit forms a BTL (bridge type) power amplification driving circuit, obtains the effect of low-voltage power supply and high-voltage output, and solves the problem that the existing power amplifier cannot meet the requirement of high-voltage output. The current output signal flowing through the hollow coil is sampled and fed back by a precision AC/DC current transformer and then is sent to the PID input end to be compared with the standard current signal, and automatic correction is carried out; in an embodiment of the application, the BTL alternating current power amplification module includes a third PID adjustment circuit, a level conversion circuit, a forward power amplifier, a reverse power amplifier, an iH port, and an iL port, and the level conversion circuit includes a forward conversion circuit and a reverse conversion circuit; the input end of the third PID regulating circuit is connected with the program control standard signal source through a switch K2, and the feedback input end of the third PID regulating circuit is connected with the second movable end of the change-over switch K5; the output end of the third PID regulating circuit is respectively connected with the forward conversion circuit and the reverse conversion circuit, the output end of the forward conversion circuit is connected with the iH port through a forward power amplifier, and the output end of the reverse conversion circuit is connected with the iL port through a reverse power amplifier;
as shown in fig. 5, the level conversion circuit is composed of input resistors R1-R5, an operational amplifier, a detection circuit, an automatic gain control AGC circuit, etc., and is transmitted to the conversion circuit for forward and reverse conversion, and the conversion circuit samples the output of the forward conversion operational amplifier and the output of the reverse conversion operational amplifier, and the output of the forward power amplifier and the output of the reverse power amplifier through the signal detection circuit; through the comparison amplifying circuit, the automatic AGC control circuit performs feedback compensation, so that the two paths of signals can still counteract the load influence after being loaded, and the two paths of signals are ensured to have equal amplitude and opposite phases; the obtained signals with the same amplitude and the same phase are respectively sent to a forward power amplifier and a reverse power amplifier for power amplification, and the circuit is the key for ensuring the balanced output of the BTL circuit.
The switch K4 comprises two closed sub-switches which are synchronously opened, an iH port is connected with the first end of the air core coil through one of the sub-switches, and an iL port is connected with the second end of the air core coil through the other sub-switch.
In the embodiment of the application, the alternating current and direct current transformers are adopted by adopting the latest current sampling technology, and alternating current and direct current sampling can be realized by using one set of current transformers, so that the problem that multiple processes of alternating current and direct current are used for carrying out detection and calibration respectively for multiple times is solved, the working efficiency is improved, and the manufacturing cost is reduced; the problem that the temperature drift caused by heating of the resistor during sampling of the conventional resistor is changed to cause electric parameters is solved.
The multi-turn air-core coil technology is adopted, and the effect of obtaining large ampere-turn ratio output by the small current technology is achieved. According to the ampere-turn calculation formula I N and the same ampere-turn requirement, the larger N is, the smaller I can be, and the smaller current is, the less strict working requirement on the power amplifier is, so that the safety and stability of the system can be greatly improved.
The working principle of the utility model is as follows: after a user sets voltage, current, phase, period or time parameters needing to be output and measured through the VFD keyboard, the VFD keyboard transmits the parameters set by the user to the program-controlled standard voltage source; the program control standard signal source generates two-phase standard voltage signals and current signals according to user setting, and the voltage signals are sent to a PID regulating circuit of the AC/DC voltage power amplifier circuit; the PID regulating circuit carries out proportional, integral and differential processing on the standard signal and the standard voltage feedback signal and then transmits the standard signal and the standard voltage feedback signal to the AC/DC voltage power amplifier; and the power amplifier transmits the standard voltage signal amplified by the weak signal to a welding current monitor, and the welding current monitor displays relevant voltage information. The direct current signal is sent to a PID regulating circuit of the direct current power amplifier circuit; the PID regulating circuit carries out proportional, integral and differential processing on the standard signal and the standard current feedback signal and then transmits the standard signal and the standard current feedback signal to the direct current power amplifier; the power amplifier sends the standard current signal amplified by the weak signal to the hollow coil, and the welding current monitor acquires a direct current signal through Rogowski coil monitoring to display the numerical value. The alternating current signal is sent to a PID regulating circuit of the alternating current power amplifier circuit; the PID adjusting circuit carries out proportion, integration and differentiation processing on the standard signal and the standard current feedback signal and then transmits the standard signal and the standard current feedback signal to the BTL alternating current power amplifying module, and a level conversion circuit in the BTL alternating current power amplifying module firstly carries out positive amplification on the signal and simultaneously converts a negative signal with opposite phase and equal amplitude absolute value; specifically, the level conversion circuit samples the output of the operational amplifier and the output of the power amplifier through the signal detection circuit respectively; the automatic AGC control circuit ensures that the two paths of signals can still offset the load influence after being loaded, and ensures that the amplitudes of the two paths of signals are equal and the phases are opposite; then the two signals with equal amplitude and opposite positive and negative directions are respectively sent to a positive power amplifier and a negative power amplifier for power amplification, then the current signal and the voltage after the positive power amplification are synchronously sent to the high end of the hollow coil, the current signal and the voltage after the negative power amplification are synchronously sent to the low end of the hollow coil, and the welding current monitor obtains the set output alternating current signal through Rogowski coil monitoring and displays the value. The staff notes survey voltage amplitude, current amplitude and the cycle number of welding current monitor, compares with the parameter that the user set for through the VFD keyboard, accomplishes welding current monitor's calibration, and the calibration mode is as follows:
equation 1: voltage measurement error = ((measured value-set value) ÷ set value) + correction value
Equation 2: current measurement error = ((measured value-set value) ÷ set value) + correction value
Equation 3: cycle number measurement error = (measured value-set value) ÷ set value
Measured value: the welding current monitor is used for actually measuring the electric parameter result.
Setting value: the user sets the value of the electric parameter to be output through the VFD keyboard.
Correction value: the error correction value after the system tracing calibration is used for compensating the error information of the calibration device, but the correction value is measured in advance and can be regarded as a known quantity in the application; in some embodiments, the correction values may also be ignored directly.
While the foregoing description shows and describes a preferred embodiment of the invention, it is to be understood, as noted above, that the invention is not limited to the forms disclosed herein, but is not intended to be exhaustive or to exclude other embodiments and may be used in various other combinations, modifications, and environments and is capable of changes within the scope of the inventive concept as expressed herein, commensurate with the above teachings, or the skill or knowledge of the relevant art. But that modifications and variations may be effected by those skilled in the art without departing from the spirit and scope of the invention, which is to be limited only by the claims appended hereto.
Claims (7)
1. The utility model provides a welding current monitor calibrating device which characterized in that: the system comprises a VFD keyboard, a program-controlled standard signal source, an AC/DC voltage power amplification module, a DC current power amplification module, a BTL AC current power amplification module, an air-core coil, an AC/DC current transformer and a welding current monitor;
the output end of the VFD keyboard is connected with a program-controlled standard signal source, the output end of the program-controlled standard signal source is connected with the signal input end of an AC/DC voltage power amplification module, and the output end of the AC/DC voltage power amplification module is connected with a welding current monitor; the output end of the AC/DC voltage power amplification module is also connected with the feedback input end of the AC/DC voltage power amplification module;
the signal input end of the direct current power amplification module is connected with the output end of the program control standard signal source through a switch K1, and the output end of the direct current power amplification module is connected with the hollow coil through a switch K3;
the signal input end of the BTL alternating current power amplification module is connected with the output end of the program control standard signal source through a switch K2, and the output end of the BTL alternating current power amplification module is connected with the hollow coil through a switch K4;
the alternating current and direct current transformer is used for detecting the hollow coil, and the output end of the alternating current and direct current transformer is connected to the feedback signal input ends of the direct current power amplification module and the BTL alternating current power amplification module through a change-over switch K5.
2. The welding current monitor calibration device of claim 1, wherein: the welding current monitor is connected with a Rogowski coil.
3. The welding current monitor calibration device of claim 1, wherein: the change-over switch K5 is a single-pole double-throw switch, the moving end of the change-over switch K5 is connected with the output end of the alternating current and direct current transformer, the first moving end of the change-over switch K5 is connected with the feedback signal input end of the direct current power amplification module, and the second moving end of the change-over switch K5 is connected with the feedback signal input end of the BTL alternating current power amplification module.
4. The welding current monitor calibration device of claim 1, wherein: the program control standard signal source comprises an ARM micro control processor, a CPLD chip, a first DAC module, a second DAC module and a crystal oscillator; the output end of the crystal oscillator is respectively connected with the ARM micro-control processor and the CPLD chip and is used for providing a clock reference for the ARM micro-control processor and the CPLD chip; the input end of the ARM micro-control processor is connected with the VFD keyboard, the output end of the ARM micro-control processor is respectively connected with the first DAC module and the second DAC module through the CPLD chip, the output end of the first DAC module is connected with the alternating current-direct current voltage power amplification module, and the output end of the second DAC module is respectively connected with the switch K1 and the switch K2.
5. The welding current monitor calibration device of claim 1, wherein: the AC/DC voltage power amplification module comprises a first PID regulating circuit and an AC/DC voltage power amplifier, the signal input end of the first PID regulating circuit is connected with a program-controlled standard signal source, the output end of the first PID regulating circuit is connected with the AC/DC voltage power amplifier, the output end of the AC/DC voltage power amplifier is connected with the welding current monitor, and the output end of the AC/DC voltage power amplifier is also connected with the feedback input end of the first PID regulating circuit.
6. The welding current monitor calibration device of claim 1, wherein: the direct current power amplification module comprises a second PID regulating circuit and a direct current power amplifier, the input end of the second PID regulating circuit is connected with the program control standard signal source through a switch K1, and the feedback input end of the second PID regulating circuit is connected with the first movable end of a change-over switch K5; the output end of the second PID regulating circuit is connected with a direct current power amplifier, and the output end of the direct current power amplifier comprises an IH end and an OV end;
the switch K3 includes two sub-switches that are synchronously opened and closed, wherein the IH terminal is connected to the first terminal of the air core coil through the first sub-switch of the switch K3, and the OV terminal is connected to the second terminal of the air core coil through the second sub-switch of the switch K3.
7. The welding current monitor calibration device of claim 1, wherein: the BTL alternating current power amplification module comprises a third PID regulating circuit, a level conversion circuit, a forward power amplifier, a reverse power amplifier, an iH port and an iL port, wherein the level conversion circuit comprises a forward conversion circuit and a reverse conversion circuit; the input end of the third PID regulating circuit is connected with the program control standard signal source through a switch K2, and the feedback input end of the third PID regulating circuit is connected with the second movable end of the change-over switch K5; the output end of the third PID regulating circuit is respectively connected with the forward conversion circuit and the reverse conversion circuit, the output end of the forward conversion circuit is connected with the iH port through a forward power amplifier, and the output end of the reverse conversion circuit is connected with the iL port through a reverse power amplifier;
the switch K4 comprises two closed sub-switches which are synchronously opened, an iH port is connected with the first end of the air core coil through one of the sub-switches, and an iL port is connected with the second end of the air core coil through the other sub-switch.
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| CN202120781517.4U CN214585937U (en) | 2021-04-16 | 2021-04-16 | Welding current monitor calibrating device |
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| CN202120781517.4U CN214585937U (en) | 2021-04-16 | 2021-04-16 | Welding current monitor calibrating device |
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