CN101400471A

CN101400471A - Welding equipment

Info

Publication number: CN101400471A
Application number: CNA2007800004405A
Authority: CN
Inventors: 栩野雅充; 梅田亘
Original assignee: Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Holdings Corp
Priority date: 2006-12-12
Filing date: 2007-04-24
Publication date: 2009-04-01
Anticipated expiration: 2027-04-24
Also published as: JP4935679B2; CN101400471B; WO2008072387A1; JPWO2008072387A1

Abstract

Conventional welding equipment has such a problem that when a fuse or a circuit breaker is not provided in the welding equipment, the fuse or circuit breaker in a switchboard for supplying power to the welding equipment must have such a value as can prevent burning of an apparatus in case of short circuit failure of a semiconductor element, and the welding equipment cannot be protected when a fuse or a circuit breaker having a higher value is used. Spreading of failure is achieved through a simple arrangement with low cost by monitoring the voltage of the semiconductor element, and interrupting an input power supply when the voltage applied to the semiconductor element becomes zero or lower than a normal voltage, thereby interrupting input power supply to the welding equipment.

Description

Welder

Technical field

The present invention relates to use the welder of semiconductor element, and be the welder that can detect the fault detect of this semiconductor element.

Background technology

In recent years, worldwide strengthened with respect to the cooperation of the safety of equipment.When semiconductor element such as employed IGCT produces short trouble in welder, be not limited only to the fault of semiconductor element, sometimes also simultaneously structure members such as transformer burnt.

In welder in the past, the guard method when producing short trouble and in the well-known technology, following described technology is arranged as semiconductor element.

For example, in the controller switching equipment that electric power is provided to welder, input power circuit, be provided with fuse, circuit brake.Thereby, when semiconductor element produces short trouble, owing to flow through excessive input current; so fuse blows, perhaps circuit brake tripping operation (trip) prevents to constitute the transformer scaling loss of welder etc. thus; prevent the expansion (for example, with reference to patent documentation 1) of fault.

Fig. 3 represents the general structure of described welder in the past.

In this welder in the past, when input contact maker 101 closures, input power supply (U, V, W) is provided for the elementary winding 121 of three-phase alternating current with main transformer 122.The output voltage of its secondary windings 102a～102f via alternate reactance 104, direct current reactance 105, offers weld load 106 as the welding output current by IGCT 103a～103f rectification.At this moment, in each IGCT 103a～103f, flow through the welding output current is divided into electric currents after 6 parts.

On their control circuit 110 of control, be provided with to prevent to produce and bring the protection fuse 107 of influence for other place when unusual.

Here, when one or more IGCT 103a～103f produced short trouble for a certain reason, the output of the secondary windings 102a～102f of welding transformer was by the some institutes short circuit among the IGCT 103a～103f of fault, thereby flow through excessive electric current.When excessive electric current flow through, the protection that is arranged in the power distribution equipment that is connected on this welder fused with fuse (not shown), perhaps circuit brake (not shown) tripping operation, thereby protection welder.

But; when having connected the fuse bigger, circuit brake than setting; even IGCT 103a～103f produces short trouble, fuse or circuit brake also are failure to actuate sometimes, and secondary windings 102a～102f and the elementary winding 121 of three-phase alternating current with main transformer 122 burnt.

In addition, even thereby be installed in fuse blows protection welder on the distribution box etc., also have replace need the time, owing to being that jumbo fuse is replaced parts than problems such as costlinesses.

Like this, in welder in the past, when not having fuse or circuit brake in the welder, must on distribution box that electric power is provided to welder etc., fuse, circuit brake be set.And then; as this fuse, circuit brake; must specify to have the type that when semiconductor element produces short trouble, can prevent the value of burning of equipment, when use has type more than or equal to the value that can prevent, have the problem that to protect equipment.

In addition, when equipment fuse or circuit brake in welder, the configuration space of welder also increases.And, need fuse or protector, so have the problem that cost also raises by big electric current.

Summary of the invention

The present invention when semiconductor element produces fault, simply and at low cost cuts off the input power supply of welder in order to solve above-mentioned problem, prevents the expansion of fault.

In order to solve above-mentioned problem, welder of the present invention comprises: transformer; Switch portion, the primary side that it is set at transformer is used for transformer is provided or cut off alternating current; Semiconductor element, the primary side that it is set at transformer is used for control welding output; And voltage detection department, it detects the both end voltage of semiconductor element; Wherein,, switch portion is disconnected action, cut off the alternating current of supplying with to transformer when the both end voltage that detects semiconductor element at voltage detection department when transformer provides alternating current is lower or when being zero than common voltage.

In addition, welder of the present invention, wherein: semiconductor element is provided with a plurality of, a plurality of semiconductor elements are connected in parallel, in a plurality of semiconductor elements each is provided with voltage detection department, the both end voltage that detects semiconductor element at least one voltage detection department is lower or when being zero than common voltage, and switch portion is disconnected action, cuts off the alternating current of supplying with to transformer.

In addition, welder of the present invention, wherein: the both end voltage that detects semiconductor element more than the lasting stipulated time at voltage detection department is lower or when being zero than common voltage, and switch portion is disconnected action, cuts off the alternating current of supplying with to transformer.

In addition, welder of the present invention comprises: the 1st relay; The 2nd relay; Capacitive element, itself and the 2nd relay are connected in parallel; And switch element, its testing result based on voltage detection department makes the 2nd relay carry out on-off action; Wherein, by the 1st actuating of relay, the 2nd relay with capacitive element in the suitable regulation of stored energy carry out closed action in holding time; Carry out closed action by the 1st relay and the 2nd relay, switch portion is carried out closed action, provides alternating current to transformer; When the both end voltage that detects semiconductor element at voltage detection department is common voltage, carry out closed action by switch element, even, transformer is kept the supply of alternating current having passed through the closed action of also keeping the 2nd relay after regulation is held time; The both end voltage that detects semiconductor element at voltage detection department is lower or when being zero than common voltage, disconnects action by switch element, disconnects action having passed through regulation back the 2nd relay of holding time, and transformer is cut off the supply of alternating current.

By such structure, welder of the present invention monitors the voltage of semiconductor element, be zero or cut off the input power supply when lower at the voltage of semiconductor element than common voltage, thereby cut off of the supply of input power supply, realize the preventing of expansion of fault thus with simple structure and lower cost to welder.

Description of drawings

Fig. 1 is the figure of schematic configuration of the welder of expression an embodiment of the invention.

Fig. 2 is the figure of structure of control part of input contact maker of the welder of expression an embodiment of the invention.

Fig. 3 is the figure that represents the schematic configuration of welder in the past.

Symbol description

1,101: the input contact maker

10: rise and employ switch

11: transistor (switch element)

11a: base stage

2: welding transformer

2a, 121: elementary winding

2b, 102a, 102b, 102c, 102d, 102e, 102f: secondary windings

3a, 3b, 3c, 3d, 3e, 3f, 103a, 103b, 103c, 103d, 103e, 103f: IGCT

4a, 4b, 4c, 4d, 4e, 4f: the emission side element of photo-coupler

5a, 5b, 5c, 5d, 5e, 5f: the sensitive side element of photo-coupler

6a, 6b, 6c, 6d, 6e:AND element

7: the 1 relays

71: the 1 systems

72: the 2 systems

8: the 2 relays

9: control part

91: electric capacity

92: resistance

The specific embodiment

Fig. 1 is the figure of schematic configuration of the welder of expression an embodiment of the invention.Present embodiment is the example that applies the present invention to most double star rectifier circuit that utilizes IGCT that uses in the welder.

As shown in Figure 1, this double star rectifier circuit comprises the input contact maker 1 and the welding transformer 2 of the input power supply that opens and closes welder, and welding transformer 2 comprises elementary winding 2a and secondary windings 2b.Also comprise as the IGCT 3a～3f that the output of welding transformer 2 is carried out the power semiconductor of rectification, owing to being the double star rectifier circuit structure, so 6 IGCT 3a～3f are connected in parallel.

In addition, or inverse parallel in parallel with IGCT 3a～3f is connected with the emission side element 4a～4f of the photo-coupler that is connected in series with electric current limiting resistance and diode.In addition, arrowed symbol K1～K6 represents the arrow of same-sign is connected each other among Fig. 1.

And then the output of the sensitive side element 5a～5f of photo-coupler is connected via the input of voltage regulator resistor with the AND element 6a～6e that constitutes sequence circuit.The structural table of the control part 9 of the input contact maker 1 of the welder of present embodiment is shown among Fig. 2.In addition, in Fig. 1 and Fig. 2, arrowed symbol m1～m3 represents the arrow of same-sign is connected each other.

This control part 9 comprises the 1st relay 7 and the 2nd relay 8 with normally opened contact and normally-closed contact as shown in Figure 2.The 1st relay 7 is switch the

1st system

71 and 72 these two systems of the 2nd system simultaneously.

In addition, the normally opened contact of the 1st relay 7 is connected with tie point 1a.In addition, the normally opened contact of the 2nd relay 7 is connected with tie point 1b via the coil portion 1c of the input contact maker 1 that is used to make the contact action of importing contact maker 1.In addition, the normally opened contact of the normally opened contact of the 1st relay 7 and the 2nd relay 7 is connected in series.Thereby, the normally opened contact conducting (closing of contact) of normally opened contact and the 2nd relay 7 by the 1st relay 7, when becoming the state that tie point 1a and tie point 1b are coupled together, contact maker 1 becomes closure state thereby electric current flows into coil portion 1c input.That is, become the state that the input power supply is offered welding transformer 2.On the other hand, end (contact disconnection) by the normally opened contact of the 1st relay 7 or the normally opened contact of the 2nd relay 7, when becoming without state that coil portion 1c couples together tie point 1a and tie point 1b, contact maker 1 becomes off-state thereby electric current does not flow into coil portion 1c input.That is, do not become and will import the state that power supply offers welding transformer 2.

As can be seen from Figure 2, employ under the state that switch 10 ends rising, in the coil of the 1st relay 7, do not flow through electric current, the 1st relay 7 be a cut-off state, and is the state that is connected cut-out with tie point 1a and tie point 1b.Therefore, input contact maker 1 becomes off-state.In addition, under this state, in the coil of the 2nd relay 8, flow through predetermined electric current via the normally-closed contact in the 2nd system 72 of the 1st relay 7, the 2nd relay 8 becomes conducting state.

Under this state, rise when employing switch 10 in conducting, coil at the 1st relay 7 flows through predetermined electric current, the 1st relay 7 becomes conducting, the 2nd relay 8 also is conducting, so tie point 1a is connected via the coil portion 1c of the 1st relay the 7, the 2nd relay 8 with input contact maker 1 with tie point 1b.In addition, at this moment, in the 2nd system 72 of the 1st relay 7, normally-closed contact becomes off-state.But the 2nd relay 8 is kept conducting state.Its reason describes in detail in the back.

Like this, tie point 1a and tie point 1b are connected, and become closure state thereby flow through electric current input contact maker 1 in coil portion 1c.Thereby, apply voltage to IGCT 3a～3f via welding transformer 2.IGCT 3a～3f carries out rectification to the voltage that is applied, and DC voltage is offered weld part 20.In addition, between the anode negative electrode of IGCT 3a～3f, be applied with the ac output voltage of welding transformer 2.

Here, when becoming short-circuit condition between the anode negative electrode of some or certain the several fault in IGCT 3a～3f, the IGCT 3a～3f of fault, the IGCT 3a～3f that produces short trouble can not stop and is applied to voltage on the anode.Thereby the IGCT 3a～3f by fault and be connected other IGCT 3a～3f on the secondary windings 2b has constituted short circuit current on the secondary windings 2b of welding transformer 2, flow through super-high-current in IGCT 3a～3f and welding transformer 2.

And then, when this state continuance, can cause the secondary windings 2b and the elementary winding 2a of welding transformer 2 are burnt.In addition, not some IGCT 3a～3f fault, too, flowing through super-high-current during but a plurality of IGCT 3a～3f fault thereby constitute short circuit current.

In order to prevent above-mentioned state, in the welder of present embodiment, be set as the structure of voltage between the anode negative electrode that monitors IGCT 3a～3f.For voltage between the anode negative electrode that monitors IGCT 3a～3f, with the in parallel or antiparallel mode of each IGCT 3a～3f, connect the circuit that is connected in series that emission side element 4a～4f, diode and electric current limiting resistance by photo-coupler constitute.In addition, diode is used to prevent the overvoltage of the emission side element 4a～4f of photo-coupler, and resistance is used to limit electric current.

When welder normally moves, between the anode negative electrode of IGCT 3a～3f, be applied with voltage, so because this voltage, thereby it is luminous to flow through electric current in the emission side element 4a～4f of photo-coupler, and light is passed to the sensitive side element 5a～5f of photo-coupler.Thereby the sensitive side element 5a～5f of photo-coupler becomes conducting, and this signal is via the sequence circuit that is made of AND element 6a～6e, and the lead-out terminal 6f of AND element 6e is made as high state.

The lead-out terminal 6f of this AND element 6e is transfused to the base stage 11a as the transistor 11 of switch element, and transistor 11 is made as conducting state.

Because transistor 11 becomes conducting state, so cross predetermined electric current in the coil relaying afterflow of the 2nd relay 8, the 2nd relay 8 remains conducting state.Therefore, be maintained the state that tie point 1a and tie point 1b are coupled together, contact maker 1 is maintained closure state.

Action when next, the some or a plurality of IGCT 3a among 6 IGCT 3a～3f～3f being produced short trouble describes.

When some the or a plurality of IGCT 3a in IGCT 3a～3f～3f produces short trouble, voltage vanishing or the voltage lower between the anode negative electrode of this IGCT 3a～3f than common voltage.Thereby, being connected and no longer including electric current among the emission side element 4a～4f of the photo-coupler between the anode negative electrode of IGCT 3a～3f and flow through, the sensitive side element 5a～5f of corresponding photo-coupler becomes cut-off state.

Its result, some input terminals of the correspondence among AND element 6a～6e become low state, and the lead-out terminal 6f of AND element 6e also becomes low state.The lead-out terminal 6f of this AND element 6e is connected with the base stage 11a of transistor 11, so transistor 11 becomes cut-off state.

At this moment, rise and to employ switch 10 and become conducting state, so the 1st relay 7 becomes conducting state, the normally-closed contact of the 2nd system 72 of the 1st relay 7 becomes off-state.Therefore, no longer flow through electric current in the coil of the 2nd relay 8, the 2nd relay 8 becomes cut-off state.

Thus, tie point 1a and tie point 1b no longer are connected, and no longer flow through electric current in coil portion 1c, and input contact maker 1 becomes off-state, will supply with the input dump of welder.

In addition, as the 1st relay the 7, the 2nd relay 8 of control part 9, can use semiconductor switch such as electromagnetic contactor or the contact maker equal, bidirectional triode thyristor with it.

Monitor the voltage of IGCT 3a～3f as described above, when the generation short trouble of IGCT 3a～3f, little or vanishing when voltage becomes than operate as normal between the anode negative electrode of IGCT 3a～3f, so by detecting this situation, can be by cutting off the input power supply by input contact maker 1, prevent the expansion of fault of the structure member of welding transformer 2 welders such as grade.

In addition, detect the voltage of each IGCT 3a～3f, because by with this testing result being the sequential circuit of keeping or end (disconnection) that the AND element 6a corresponding with each IGCT 3a～3f～6e of input constitutes conducting (closure) state of importing contact maker 1, so when at least one IGCT 3a～3f produces fault, can be with input contact maker 1 by (disconnection).

In addition, represented when the voltage of the IGCT 3a～3f that is monitored becomes than operate as normal moment little or vanishing will import contact maker 1 by (disconnection) thus will import the example of dump, but also can do like this: thereby when IGCT 3a～3f does not produce the fault operate as normal but descends owing to the voltage of certain reason IGCT 3a～3f such as noise, for the purpose that prevents that flase drop from surveying, state continuance little or vanishing will be imported contact maker 1 by (disconnection) during the stipulated time when the voltage of IGCT 3a～3f becomes than operate as normal, thereby will import dump.

Action when next, the welder that makes present embodiment being started describes.

At this welder prestart, the input power supply is cut off, so do not apply voltage on welding transformer 2, does not also apply voltage on the IGCT 3a～3f that is connected on the secondary windings 2b of welding transformer 2.Therefore, also do not flow through electric current in the emission side element 4a～4f of photo-coupler, erroneous judgement is decided to be IGCT 3a～3f short circuit, and the lead-out terminal 6f of AND element 6e becomes low state, and transistor 11 also becomes cut-off state.

Under this state, rise employ switch 10 by the time, the 1st relay 7 becomes cut-off state, the 2nd relay 8 becomes conducting state.

But, employ switch 10 when this state becomes conducting state rising, the 1st relay 7 becomes conducting state, and the normally-closed contact of the 2nd system 72 of the 1st relay 7 becomes off-state.And then IGCT 3a～3f does not also flow through electric current in this stage, so the lead-out terminal 6f of AND element 6e keeps low state, transistor 11 does not become conducting state yet.Therefore, do not flow through electric current in the coil of the 2nd relay 8, the 2nd relay 8 can not become conducting state.That is, no matter until what time, all input contact maker 1 can not be made as conducting state (closure state).

Therefore, the series circuit that is connected in parallel on the coil of the 2nd relay 8 and is made of electric capacity 91 and resistance 92 forms following structures: even thereby rise and employ that the normally-closed contact that switch 10 becomes the 2nd system 72 of conducting state the 1st relay 7 becomes off-state, the electric current that charges into electric capacity 91 continues to cross at the coil midstream of the 2nd relay 8, the 2nd relay 8 is maintained conducting state in certain time.Like this, become and have a certain time delay till conducting state to the 2 relays 8 become cut-off state from employing switch 10.

That is, at the prestarting holding state of welder, the 2nd relay 8 becomes conducting state.

Thereby, import contact maker 1 for conducting, conducting rises employs switch 10, when the 1st relay 7 becomes conducting state thus, its normally-closed contact becomes disconnection, but the electric current that charges into electric capacity 91 continues to flow in traveling time, and the 2nd relay 8 during this period of time is maintained conducting state.

During this period of time, the 1st relay 7 and the 2nd relay 8 are conducting state simultaneously, and the input terminal 1a and the 1b of control part 9 are connected, and control part 9 becomes conducting state, and input contact maker 1 becomes conducting state (closure).

Like this, become conducting state by input contact maker 1, be applied with voltage between the anode negative electrode of IGCT 3a～3f, by detecting this voltage, the lead-out terminal 6f of AND element 6e becomes high state.This is transfused to the base stage 11a of transistor 11, and transistor 11 becomes conducting state, and the 2nd relay 8 is kept conducting state, and input contact maker 1 also can keep conducting state (closure).

In addition, in the present embodiment, represented to use the example of the circuit of relay as the circuit that makes welder starting, but be not limited thereto, used other parts such as logic IC, transistor circuit also can realize.

In addition, present embodiment is narrated for the double star rectifier circuit that the IGCT by three-phase input constitutes, but also can be applied to other rectification circuit structure and single-phase input rectification circuit, the semiconductor circuit that is made of other control element.

The expansion of the infringement that the present invention can will be caused by the fault of the semiconductor element that is used for welder by low-cost and simple structure prevents trouble before it happens, as the welder that has improved security, industrial extremely useful.

Claims

1. welder, it comprises:

Transformer;

Switch portion, the primary side that it is set at described transformer is used for described transformer is provided or cut off alternating current;

Semiconductor element, the primary side that it is set at described transformer is used for control welding output; With

Voltage detection department, it detects the both end voltage of described semiconductor element;

Wherein, lower or when being zero when detect the both end voltage of described semiconductor element at described voltage detection department when described transformer provides described alternating current than common voltage, described switch portion is disconnected action, cut off the described alternating current of supplying with to described transformer.

2. welder as claimed in claim 1, wherein: described semiconductor element is provided with a plurality of, described a plurality of semiconductor element is connected in parallel, in described a plurality of semiconductor elements each is provided with described voltage detection department, the both end voltage that detects described semiconductor element at least one described voltage detection department is lower or when being zero than common voltage, described switch portion is disconnected action, cut off the described alternating current of supplying with to described transformer.

3. welder as claimed in claim 1, wherein: the both end voltage that detects described semiconductor element more than the lasting stipulated time at described voltage detection department is lower or when being zero than common voltage, described switch portion is disconnected action, cut off the described alternating current of supplying with to described transformer.

4. as any described welder in the claim 1～3, it also comprises:

The 1st relay;

The 2nd relay;

Capacitive element, itself and described the 2nd relay are connected in parallel; With

Switch element, its testing result based on described voltage detection department make described the 2nd relay carry out on-off action;

Wherein, by described the 1st actuating of relay, described the 2nd relay with described capacitive element in the suitable regulation of stored energy carry out closed action in holding time;

Carry out closed action by described the 1st relay and described the 2nd relay, described switch portion is carried out closed action, thereby provides described alternating current to described transformer;

When the both end voltage that detects described semiconductor element at described voltage detection department is common voltage, carry out closed action by described switch element, even, described transformer is kept the supply of described alternating current having passed through the closed action of also keeping described the 2nd relay after described regulation is held time; The both end voltage that detects described semiconductor element at described voltage detection department is lower or when being zero than common voltage, disconnect action by described switch element, disconnect action having passed through described regulation back the 2nd relay of holding time, cut off the described alternating current of supplying with to described transformer.