CN103286418A - Three-phase welder circuit - Google Patents
Three-phase welder circuit Download PDFInfo
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- CN103286418A CN103286418A CN2012100527063A CN201210052706A CN103286418A CN 103286418 A CN103286418 A CN 103286418A CN 2012100527063 A CN2012100527063 A CN 2012100527063A CN 201210052706 A CN201210052706 A CN 201210052706A CN 103286418 A CN103286418 A CN 103286418A
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Abstract
The invention discloses a three-phase welder circuit which comprises a first isolation element, a second isolation element and a third isolation element; a primary circuit of a welder main circuit is connected with the input end of a three-phase power supply; the output end of a secondary circuit is an output end of a welder; a control circuit comprises a control unit and a signal enabling and extracting circuit; the control unit is used for controlling the primary circuit and the secondary circuit through the signal enabling and extracting circuit; the signal output end of a differential detection circuit is connected with the control unit; the input end of the differential detection circuit is connected with that of the three-phase power supply; the first isolation element is connected with the power ground of the control unit and a housing of the welder; the second isolation element is connected with an anode at the output end of the welder and the housing; and the third isolation element is connected with a cathode at the output end of the welder and the housing. According to the three-phase welder circuit, a heavy and high-cost power-frequency transformer is cancelled, the circuit structure is simple, the welder volume is small, the detection precision is high, and the welder cost can be reduced.
Description
[technical field]
The present invention relates to welding equipment, relate in particular to a kind of three-phase welding machine circuit.
[background technology]
The welding machine of existing three-phase input generally adopts the system of no center line, input line voltage is higher, but the shell of welding machine and when requiring actual welding output voltage within the safe voltage scope, therefore the insulating requirements of welding machine is very strict, main high requirement of withstand voltage and the high impedance requirement that embodies between input and output, input and ground, output and the ground.Therefore, detect if want to reach high-precision input voltage, just must resolve the requirement of high input impedance and the high dielectric voltage withstand of insulation system requirement.
Traditional three-phase input welding machine adopts Industrial Frequency Transformer elder generation isolated buck, realizes high withstand voltage and high input impedance, connects low-voltage detection circuit after again, as shown in Figure 1, A, B are any two-phase of three-phase input, a, b is for isolating transformation voltage output afterwards through Industrial Frequency Transformer T1.By operational amplifier U1 and resistance R 1, R2, R3, R4 forms the difference amplification detection circuit.Because Industrial Frequency Transformer has certain impedance and frequency characteristic, under different input voltages, frequency, output loading, Industrial Frequency Transformer has different output accuracies, and is very big to the influence of back low-voltage detection circuit accuracy of detection.The precision of difference amplification detection circuit of power frequency transformation back own is high again, also is difficult to realize the high accuracy of whole detection.
Withstand voltage and impedance specific requirement such as table 1 and table 2 of butt welding machine in the GB:
Table 1 welding machine voltage-withstand test value standard
| Input | Output | PE | |
| Input | —— | —— | —— |
| Output | 5300Vdc | —— | —— |
| PE | 2650Vdc | 1414Vdc | —— |
The requirement of table 2 welding machine insulaion resistance
| Input | Output |
| Input | —— | —— |
| Output | 5M | —— |
| PE | 2.5M | 2.5M |
Signal in traditional three-phase welding machine input-output system shown in Figure 2 enables to form by devices such as optocoupler, transformer, CT, Halls with signal extraction unit, and the former secondary of these devices is that certain withstand voltage restriction is arranged, and is general withstand voltage all about 3500 volts.If it is very low that the front end of low-voltage detection circuit does not adopt Industrial Frequency Transformer T1 isolation transformation will cause comprising the equiva lent impedance of control chip between interior control circuit and three-phase input.And signal enables to exceed one or two order of magnitude with the equiva lent impedance of signal extraction unit than the equiva lent impedance of R1, R4 formation in parallel, causes the withstand voltage very major part of volt more than 5000 to drop on signal and enables on the components and parts with signal extraction unit.Preposition Industrial Frequency Transformer T1 had both solved the problem of withstand voltage of control circuit components and parts, had also solved the requirement of impedance.
In sum, there is following shortcoming in the welding machine of traditional three-phase input:
1. the congenital heaviness of Industrial Frequency Transformer, and have the internal resistance characteristic of can not ignore that changes with change of external conditions makes that to add the congenital accuracy of detection of detection system of low-voltage detection circuit with Industrial Frequency Transformer not high.
2. because accuracy of detection is not high and detection range is limited, can cause the protection point of input voltage under the different operating modes different, be necessary for machine system and stay certain allowance to avoid other device failure of welder system before protection more.
[summary of the invention]
It is little, in light weight that the technical problem to be solved in the present invention provides a kind of volume simple in structure, the three-phase welding machine circuit that voltage and frequency detection accuracy are high.
In order to solve the problems of the technologies described above, the technical solution used in the present invention is, a kind of three-phase welding machine circuit, comprise main circuit, differential detection circuit, control circuit, first isolated component, second isolated component and the 3rd isolated component, main circuit comprises former limit circuit and passes through transformer-coupled secondary circuit with former limit circuit, former limit circuit connects three-phase power input end, and the output of secondary circuit is the output of welding machine; Control circuit comprises that control module and signal enable and signal extracting circuit, and control module enables by signal and signal extracting circuit is controlled former limit circuit and secondary circuit; The signal output part of differential detection circuit connects described control module, the input termination three-phase power input end of differential detection circuit; First isolated component connects the power supply ground of control module and the casing of welding machine, and second isolated component connects negative pole and the casing of welding terminal, and the 3rd isolated component connects positive pole and the casing of welding terminal.
Above-described three-phase welding machine circuit, described isolated component is resistance, the first isolated component resistance R 13 connects the power supply ground of control module and the casing of welding machine, the second isolated component resistance R 14 connects negative pole and the casing of welding terminal, and the 3rd isolated component resistance R 15 connects positive pole and the casing of welding terminal.
Above-described three-phase welding machine circuit, described differential detection circuit comprises first differential amplifier circuit and second differential amplifier circuit, first differential amplifier circuit comprises first amplifier, resistance R 5, R6, R7 and R8, resistance R 5 connects the in-phase input end of first amplifier and first phase line of three-phase power input end, resistance R 6 connects in-phase input end and the described power supply ground of first amplifier, resistance R 7 connects the inverting input of first amplifier and second phase line of three-phase power input end, resistance R 8 connects the inverting input of first amplifier and the output of first amplifier, the described control module of output termination of first amplifier; Second differential amplifier circuit comprises second amplifier, resistance R 9, R10, R11 and R12, resistance R 9 connects the in-phase input end of second amplifier and second phase line of three-phase power input end, resistance R 10 connects in-phase input end and the described power supply ground of second amplifier, resistance R 11 connects the inverting input of second amplifier and the third phase line of three-phase power input end, resistance R 12 connects the inverting input of second amplifier and the output of second amplifier, the described control module of output termination of second amplifier.
Above-described three-phase welding machine circuit, the equivalent resistance after resistance R 14 and resistance R 15 parallel connections is more than or equal to 2.5M ohm.
Above-described three-phase welding machine circuit, the equivalent resistance after resistance R 5, R6, R7 and the R8 parallel connection and resistance R 13 resistance sums are more than or equal to 2.5M ohm.
Above-described three-phase welding machine circuit, the equivalent resistance after resistance R 9, R10, R11 and the R12 parallel connection and resistance R 13 resistance sums are more than or equal to 2.5M ohm.
Above-described three-phase welding machine circuit also meets the following conditions:
5300×(R13+R14//R15)/(R13+R14//R15+R5//R7//R9//R11)＜3500。
Above-described three-phase welding machine circuit, described isolated component can also be electric capacity.
Above-described three-phase welding machine circuit, described isolated component is resistance, the first isolated component resistance R 13 connects the power positive end of control module and the casing of welding machine
Three-phase welding machine circuit of the present invention has been cancelled heavy and expensive Industrial Frequency Transformer, can adopt existing low electricity resistance or electric capacity originally to realize required function, and circuit structure is simple, the welding machine volume is little; The present invention has eliminated the influence of Industrial Frequency Transformer, the accuracy of detection height.For the high-low pressure/frequency protection of input voltage rapid sensitive more, circuitry does not need to keep more margin, can further reduce the welding machine cost.
[description of drawings]
The present invention is further detailed explanation below in conjunction with the drawings and specific embodiments.
Fig. 1 is prior art three-phase welding machine input voltage detection circuit block diagram.
Fig. 2 is prior art three-phase welding machine input-output system circuit block diagram.
Fig. 3 is the three-phase welding machine circuit block diagram of the embodiment of the invention.
Fig. 4 is the equiva lent impedance figure between the embodiment of the invention three-phase welding machine input-output system.
[specific embodiment]
As shown in Figure 3, the three-phase welding machine circuit of the embodiment of the invention comprises main circuit, differential detection circuit and control circuit.A, B, C among Fig. 3 are respectively the three-phase alternating current input, and casing directly links to each other with the earth.
Main circuit comprise former limit circuit and with former limit circuit by transformer-coupled secondary circuit, former limit circuit connects three-phase power input end, the output of secondary circuit is the output of welding machine.
Control circuit comprises that control module and signal enable and signal extracting circuit, and control module enables by signal and signal extracting circuit is controlled former limit circuit and secondary circuit.
The signal output part of differential detection circuit connects control module, the input termination three-phase power input end of differential detection circuit.
(the first isolated component resistance R 13 also can be connected the power positive end of control module and the casing of welding machine for the power supply ground of the first isolated component resistance R, 13 connection control modules and the casing of welding machine, act on identical), the second isolated component resistance R 14 connects negative pole and the casing of welding terminal, the 3rd isolated component resistance R 15 connects positive pole and the casing of welding terminal, because casing directly links to each other with the earth, resistance R 14 and R15 also are equivalent to connect the earth.
Differential detection circuit comprises first differential amplifier circuit and second differential amplifier circuit.
First differential amplifier circuit comprises the first amplifier U1, resistance R 5, R6, R7 and R8, resistance R 5 connects the in-phase input end of the first amplifier U1 and the first phase line A of three-phase power input end, resistance R 6 connects in-phase input end and the power supply ground of the first amplifier U1, resistance R 7 connects the inverting input of the first amplifier U1 and the second phase line B of three-phase power input end, resistance R 8 connects the inverting input of first amplifier and the output of the first amplifier U1, the output termination control module of first amplifier.
Second differential amplifier circuit comprises the second amplifier U2, resistance R 9, R10, R11 and R12, resistance R 9 connects the in-phase input end of the second amplifier U2 and the second phase line B of three-phase power input end, resistance R 10 connects in-phase input end and the power supply ground of the second amplifier U2, resistance R 11 connects the U2 inverting input of second amplifier and the third phase line C of three-phase power input end, resistance R 12 connects the inverting input of second amplifier and the output of the second amplifier U2, the output termination control module of the second amplifier U2.
The equiva lent impedance figure of circuit shown in Figure 3 as shown in Figure 4.Because three-phase input end resistance of no use is connected to big ground, if therefore do not have the R5//R7//R9//R11 constant resistance, welding machine three-phase input end insulation against ground impedance is about about 1000M ohm.Welding machine output main control chip insulation against ground impedance is also about about 1000M ohm.
Because the insulation impedance between welding terminal and the earth must be greater than 2.5M ohm, so the equivalent resistance after resistance R 14 and resistance R 15 parallel connections should be more than or equal to 2.5M ohm.
At R5=R7=R9=R11, under the condition of R6=R8=R10=R12, because the input voltage of three-phase is much larger than testing circuit voltage, resistance R 5 is much larger than resistance R 6, therefore, equivalent resistance between three-phase input end and the earth with after resistance R 5, R6, R7 and R8 are in parallel with resistance R 13 resistance sum equivalences, should be more than or equal to 2.5M ohm.
Equally, the equivalent resistance after resistance R 9, R10, R11 and the R12 parallel connection and resistance R 13 resistance sums are more than or equal to 2.5M ohm.
Because signal enables and signal extracting circuit in the withstand voltage 3500V of having only of components and parts about, the withstand voltage standard of welding terminal is direct current 5300V, so also need also to meet the following conditions:
5300×(R13+R14//R15)/(R13+R14//R15+R5//R7//R9//R11)＜3500。
The isolated component of above embodiment adopts resistive element, and isolated component also can be to adopt electric capacity to realize impedance matching.
The above embodiment of the present invention has following effect:
1. circuit cost is low, and is simple in structure.Can only adopt existing low electricity resistance or electric capacity originally to realize.Need not adopt heavy expensive Industrial Frequency Transformer.
2. voltage and frequency detection accuracy height.For the high-low pressure/frequency protection of input voltage rapid sensitive more, the structure of machine system does not need to keep more margin.
3. the detection range of testing circuit is wide.Avoided the influence of Industrial Frequency Transformer, testing circuit can be realized the gamut linearity, and range of application is enlarged.
Claims (9)
1. three-phase welding machine circuit, comprise main circuit, differential detection circuit and control circuit, main circuit comprise former limit circuit and with former limit circuit by transformer-coupled secondary circuit, former limit circuit connects three-phase power input end, the output of secondary circuit is the output of welding machine; Control circuit comprises that control module and signal enable and signal extracting circuit, and control module enables by signal and signal extracting circuit is controlled former limit circuit and secondary circuit; The signal output part of differential detection circuit connects described control module, it is characterized in that, comprises first isolated component, second isolated component and the 3rd isolated component, the input termination three-phase power input end of differential detection circuit; First isolated component connects the power supply ground of control module and the casing of welding machine, and second isolated component connects negative pole and the casing of welding terminal, and the 3rd isolated component connects positive pole and the casing of welding terminal.
2. three-phase welding machine circuit according to claim 1, it is characterized in that, described isolated component is resistance, the first isolated component resistance R 13 connects the power supply ground of control module and the casing of welding machine, the second isolated component resistance R 14 connects negative pole and the casing of welding terminal, and the 3rd isolated component resistance R 15 connects positive pole and the casing of welding terminal.
3. three-phase welding machine circuit according to claim 2, it is characterized in that, described differential detection circuit comprises first differential amplifier circuit and second differential amplifier circuit, first differential amplifier circuit comprises first amplifier, resistance R 5, R6, R7 and R8, resistance R 5 connects the in-phase input end of first amplifier and first phase line of three-phase power input end, resistance R 6 connects in-phase input end and the described power supply ground of first amplifier, resistance R 7 connects the inverting input of first amplifier and second phase line of three-phase power input end, resistance R 8 connects the inverting input of first amplifier and the output of first amplifier, the described control module of output termination of first amplifier; Second differential amplifier circuit comprises second amplifier, resistance R 9, R10, R11 and R12, resistance R 9 connects the in-phase input end of second amplifier and second phase line of three-phase power input end, resistance R 10 connects in-phase input end and the described power supply ground of second amplifier, resistance R 11 connects the inverting input of second amplifier and the third phase line of three-phase power input end, resistance R 12 connects the inverting input of second amplifier and the output of second amplifier, the described control module of output termination of second amplifier.
4. three-phase welding machine circuit according to claim 2 is characterized in that, the equivalent resistance after resistance R 14 and resistance R 15 parallel connections is more than or equal to 2.5M ohm.
5. three-phase welding machine circuit according to claim 3 is characterized in that, the equivalent resistance after resistance R 5, R6, R7 and the R8 parallel connection and resistance R 13 resistance sums are more than or equal to 2.5M ohm.
6. three-phase welding machine circuit according to claim 3, it is characterized in that, three-phase welding machine circuit according to claim 2 is characterized in that, the equivalent resistance after resistance R 9, R10, R11 and the R12 parallel connection and resistance R 13 resistance sums are more than or equal to 2.5M ohm.
7. three-phase welding machine circuit according to claim 3 is characterized in that, meets the following conditions: 5300 * (R13+R14//R15)/(R13+R14//R15+R5//R7//R9//R11)＜3500.
8. three-phase welding machine circuit according to claim 1 is characterized in that, described isolated component is electric capacity.
9. three-phase welding machine circuit according to claim 1 is characterized in that, described isolated component is resistance, and the first isolated component resistance R 13 connects the power positive end of control module and the casing of welding machine.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201210052706.3A CN103286418B (en) | 2012-03-02 | 2012-03-02 | A kind of Three-phase welder circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201210052706.3A CN103286418B (en) | 2012-03-02 | 2012-03-02 | A kind of Three-phase welder circuit |
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| Publication Number | Publication Date |
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| CN103286418A true CN103286418A (en) | 2013-09-11 |
| CN103286418B CN103286418B (en) | 2016-03-02 |
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| CN201210052706.3A Active CN103286418B (en) | 2012-03-02 | 2012-03-02 | A kind of Three-phase welder circuit |
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5148000A (en) * | 1990-01-04 | 1992-09-15 | Crc-Evans Pipeline International, Inc. | Distributed processing control system for automatic welding operation |
| CN1748923A (en) * | 2004-09-14 | 2006-03-22 | 株式会社三社电机制作所 | Power supply apparatus for welder |
| CN2838834Y (en) * | 2005-06-20 | 2006-11-22 | 北京工业大学 | Feedback signal control circuit for double-silk MAG inverted welding power supply |
| CN101394134A (en) * | 2008-10-15 | 2009-03-25 | 江南大学 | Three-phase digital time division balance large power AC welding power source |
-
2012
- 2012-03-02 CN CN201210052706.3A patent/CN103286418B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5148000A (en) * | 1990-01-04 | 1992-09-15 | Crc-Evans Pipeline International, Inc. | Distributed processing control system for automatic welding operation |
| CN1748923A (en) * | 2004-09-14 | 2006-03-22 | 株式会社三社电机制作所 | Power supply apparatus for welder |
| CN2838834Y (en) * | 2005-06-20 | 2006-11-22 | 北京工业大学 | Feedback signal control circuit for double-silk MAG inverted welding power supply |
| CN101394134A (en) * | 2008-10-15 | 2009-03-25 | 江南大学 | Three-phase digital time division balance large power AC welding power source |
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| CN103286418B (en) | 2016-03-02 |
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