JP2020072142A - Reactor, and welding power supply including the reactor - Google Patents

Abstract

To provide: a reactor capable of improving heat dissipation while ensuring insulation between turns in each winding; and a welding power supply including the reactor.SOLUTION: A reactor 105 includes first winding 41 wound spirally, and second winding 42 wound spirally such that each turn is located between turns of the first winding 41. The first winding 41 is a coated wire formed by coating a conductor wire 41a with an insulation sheet 41b. The second winding 42 is a conductor wire that has a portion, where an insulation coating is not formed thereon, in at least part of spirally wound portions, or the second winding 42 comprises a conductor wire on which an insulation coating is formed and at least part of the insulation coating is thinner than the insulation sheet 41b of the first winding 41.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a reactor having a pair of magnetically coupled windings, and a welding power supply device including the reactor.

  For example, in a welding power supply device for AC TIG arc welding, when a half bridge circuit is used for the secondary side inverter circuit, between the positive side output terminal of the secondary side rectifier circuit and the positive side input terminal of the secondary side inverter circuit, The coils are respectively arranged between the negative side output terminal of the secondary side rectifier circuit and the negative side input terminal of the secondary side inverter circuit. These coils suppress the ripple of the direct current output from the secondary side rectifier circuit and smooth the current. In addition, these coils are magnetically coupled, and when the polarity of the secondary side inverter circuit is switched, an induced electromotive force is generated by mutual induction to assist the rising of the current and the arc due to the switching of the polarity. It also has the function of suppressing disconnection. Patent Document 1 discloses a power supply device for an AC arc welder, which includes a reactor in which two coils are magnetically coupled.

  As such a reactor, there is known a reactor in which a winding serving as a coil on the positive electrode side and a winding serving as a coil on the negative electrode side are each wound around a core in a solenoid coil shape (spiral shape). In such a reactor, a conductor wire in which an insulating film is formed is used for each winding so that the turns are not electrically connected to each other.

JP, 2004-96934, A

  However, since each winding is covered with the insulating film, the heat dissipation is poor and the temperature rise of each winding becomes a problem.

  The present invention has been devised under the circumstances described above, and an object thereof is to provide a reactor capable of improving heat dissipation while ensuring insulation between each turn in each winding. And

  The reactor provided by the first aspect of the present invention has a spirally wound first winding and a spiral winding such that each turn is located between each turn of the first winding. And a second winding wound around the first winding, wherein the first winding is a conductor wire having an insulating coating formed thereon, and the second winding is insulated at least at a part of a spirally wound portion. A conductor wire having a part where the coating is not formed, or a conductor wire having an insulating coating, and at least a part of the insulating coating is thinner than the insulating coating of the first winding. And

  In a preferred embodiment of the present invention, the second winding is a bare wire.

  In a preferred embodiment of the present invention, the conductor wire of the first winding and the conductor wire of the second winding have different cross-sectional areas.

  A welding power supply device provided by the second aspect of the present invention is characterized by including the reactor provided by the first aspect of the present invention.

  In a preferred embodiment of the present invention, the average value of the current flowing through the second winding is larger than the average value of the current flowing through the first winding.

  According to the present invention, in the second winding, the insulating coating is not formed on at least a part of the spirally wound portion, or at least the insulating coating is thinner than the insulating coating of the first winding. ing. Therefore, the heat dissipation of the second winding can be improved as compared with the case where the insulating film having the same thickness as the insulating coating of the first winding is formed over the entire surface. Thereby, the heat dissipation of the entire reactor can be improved. Further, the first winding has an insulating film formed thereon, and the first winding and the second winding are spiral so that the turns of the second winding are located between the turns of the first winding. It is wound into a shape, so-called bifilar winding. Therefore, even if there is a portion where the insulating coating is not formed on the second winding, it is possible to secure the insulation between the turns.

It is a block diagram which shows the welding power supply device using the reactor which concerns on 1st Embodiment. It is a front view which shows the reactor which concerns on 1st Embodiment. It is sectional drawing which follows the III-III line of FIG. It is a principal part expanded sectional view which follows the III-III line of FIG. It is a figure for demonstrating the connection method of the reactor which concerns on 1st Embodiment, a rectifier circuit, and an inverter circuit. It is a principal part expanded sectional view which shows the modification of the reactor which concerns on 1st Embodiment.

  Hereinafter, preferred embodiments of the present invention will be specifically described with reference to the accompanying drawings.

  FIG. 1 is a block diagram showing a welding power supply device 100 using the reactor according to the first embodiment, and shows the configuration of the entire welding system.

  The welding system shown in FIG. 1 is an AC TIG arc welding system including a welding power source device 100 and a non-consumable electrode type welding torch B. The welding power source device 100 converts AC power input from the commercial power source D and outputs the AC power from the output terminals a and b. One output terminal a is connected to the workpiece W by a cable. The other output terminal b is connected to the electrode of the welding torch B by a cable. The welding power supply device 100 generates an arc between the tip of the electrode of the welding torch B and the workpiece W to supply electric power. Welding is performed by the heat of the arc.

  The welding power supply device 100 includes a rectifying / smoothing circuit 101, an inverter circuit 102, a transformer 103, a rectifying circuit 104, a reactor 105, an inverter circuit 107, and a control circuit 108.

  The rectifying / smoothing circuit 101 converts AC power input from the commercial power supply D into DC power and outputs the DC power. The inverter circuit 102 converts the DC power input from the rectifying / smoothing circuit 101 into high frequency power and outputs it by switching the switching element by the output control drive signal input from the control circuit 108. The transformer 103 transforms the high-frequency voltage output from the inverter circuit 102 and outputs it to the rectifier circuit 104. The secondary winding of the transformer 103 is provided with a center tap in addition to the two output terminals. The center tap is connected to the output terminal b. The rectifier circuit 104 converts the high frequency power input from the transformer 103 into DC power and outputs it.

  The reactor 105 suppresses the ripple of the direct current output from the rectifier circuit 104, smoothes the current, and outputs the smoothed current to the inverter circuit 107. Further, the reactor 105 assists the rising of the current by generating an induced electromotive force by mutual induction when switching the output polarity of the inverter circuit 107, and suppresses arc breakage due to switching of the polarity. Details of the reactor 105 will be described later.

  The inverter circuit 107 is, for example, a single-phase half-bridge type PWM control inverter, and includes two switching elements Q1 and Q2. The switching element Q1 and the switching element Q2 are connected in series, and the connection point between the switching element Q1 and the switching element Q2 is connected to the output terminal a. The switching drive signal output from the control circuit 108 is input to the switching elements Q1 and Q2. The inverter circuit 107 switches the switching elements Q1 and Q2 by the switching drive signal input from the control circuit 108 so that the potential of the output terminal a is the potential of the positive output terminal of the reactor 105 and the negative output terminal of the reactor 105. Alternates with the potential of. As a result, the inverter circuit 107 has a positive polarity in which the potential of the output terminal a (connected to the workpiece W) is higher than the potential of the output terminal b (connected to the electrode of the welding torch B) and the potential of the output terminal a. Alternate with the reverse polarity which is lower than the potential of the output terminal b. That is, the inverter circuit 107 converts the DC power input from the reactor 105 into AC power and outputs the AC power. Generally, in the case of AC TIG arc welding, the positive polarity period is longer than the reverse polarity period, and for example, about 70% of one cycle is the positive polarity period. The welding power supply device 100 can also be used for DC TIG arc welding. In this case, in the inverter circuit 107, the switching element Q1 is turned on, the switching element Q2 is turned off, and the positive polarity continues.

  The control circuit 108 is a circuit for controlling the welding power supply device 100, and is realized by, for example, a microcomputer. The control circuit 108 generates an output control drive signal for feedback controlling the output current of the welding power supply device 100, and outputs the output control drive signal to the inverter circuit 102. The control circuit 108 also generates a switching drive signal, which is a pulse signal for controlling the switching elements Q1 and Q2, in order to switch the output polarity of the welding power supply device 100, and outputs the switching drive signal to the inverter circuit 107.

  The welding power supply device 100 may include a re-ignition circuit that applies a high voltage between the output terminals a and b when the output polarity is switched, a snubber circuit that absorbs a surge voltage, and the like.

  Next, details of the reactor 105 will be described.

  2 to 5 are diagrams for explaining the configuration of the reactor 105. FIG. 2 is a front view showing the reactor 105. FIG. 3 is a sectional view taken along the line III-III in FIG. FIG. 4 is an enlarged cross-sectional view of the main part taken along the line III-III of FIG. 2, and is an enlarged view of the main part of FIG. FIG. 5 is a diagram for explaining a method of connecting the reactor 105 to the rectifier circuit 104 and the inverter circuit 107.

  The reactor 105 is a reactor having a pair of magnetically coupled windings, and when a direct current flowing through one winding is cut off, mutual induction generates an induced electromotive force in the other winding. This is a circuit for suppressing arc breakage due to polarity switching. The reactor 105 includes a core 1, a fixing member 2, insulating sheets 31 and 32, an insulating member 33, and a winding portion 4. 2 to 4, the direction of the axis of the winding part 4 (the left-right direction in FIG. 2) is the x direction, the direction orthogonal to the x direction, and the up and down direction in the front view (FIG. 2) are the z directions, The direction orthogonal to the x direction and the z direction will be described as the y direction.

  The core 1 is a magnetic member for improving the coupling, and the winding portion 4 is wound around the core 1. As shown in FIG. 2, the core 1 has a rectangular ring shape that is long in the x direction when viewed in the y direction (front view). The core 1 includes a pair of L-shaped core blocks 11 and 12 and a spacer 13 when viewed in the y direction. The core block 11 and the core block 12 are combined so as to be point-symmetrical with each other when viewed in the y direction, and the core 1 as a whole has a ring shape. The configurations of the core blocks 11 and 12 are not limited. The spacer 13 is for forming a magnetic gap having a predetermined width in the core 1, and is interposed between the core block 11 and the core block 12. The spacer 13 is made of a non-magnetic material such as a synthetic resin plate. The material of the spacer 13 is not limited, and any material having a lower magnetic permeability than the core blocks 11 and 12 may be used. The configuration of the core 1 is not limited. The core 1 may be a core having no gap in which the core block 11 and the core block 12 are in contact with each other without using the spacer 13, or may be formed of one member.

  The fixing member 2 is for forming the core 1 by fixing the core blocks 11 and 12. The fixing member 2 includes two covers 21, a fixing plate 22, and a fixture 23. The two covers 21 and the fixing plate 22 sandwich the core block 11 and the core block 12 combined through the spacer 13 between the inner portion of each cover 21 and one surface of the fixing plate 22, It is fixed by the fixture 23. The method of fixing the core blocks 11 and 12 is not limited.

  The insulating sheets 31 and 32 are for insulating the core 1 and the fixing member 2. The insulating sheet 31 is interposed between the core 1 and the fixed plate 22 to insulate the core 1 and the fixed plate 22 from each other. The insulating sheet 32 is interposed between the core 1 and each cover 21, and insulates the core 1 and the cover 21 from each other. The insulating sheets 31 and 32 are made of an insulating material such as insulating paper or a synthetic resin sheet. The insulating member 33 is for insulating the core 1 and the winding portion 4 from each other. The insulating member 33 is interposed between the core 1 and the winding portion 4 to insulate the core 1 from the winding portion 4. The insulating member 33 is a rectangular plate member that is long in the x direction, has a thickness, and is elastic, and is bent at a substantially right angle to form four corner portions of the longitudinal portion 111 of the core block 11 when viewed in the x direction. It is arranged. The insulating member 33 is made of an insulating material such as synthetic resin. It should be noted that the insulating member 33 is not limited to this, as long as it can insulate the core 1 from the winding portion 4. For example, one insulating member 33 may cover the entire circumference of the longitudinal portion 111 of the core block 11 when viewed in the x direction.

  The winding portion 4 is formed in a solenoid coil shape, and is spirally wound around the longitudinal portion 111 of the core 1. The winding unit 4 includes a first winding 41 and a second winding 42. The second winding 42 is, for example, a conductor wire made of aluminum. The second winding 42 is a rectangular wire, and has a long rectangular shape whose cross section has a long side of, for example, 15 mm and a short side of, for example, 2 mm. In addition, each dimension is not limited. The second winding 42 is a bare wire that is not covered with an insulating sheet. On the other hand, the first winding 41 is a covered wire in which a conductor wire 41a, which is a rectangular wire made of aluminum, for example, is covered with an insulating sheet 41b. The cross-sectional dimension of the conductor wire 41 a of the first winding 41 is similar to that of the second winding 42. The material of the first winding wire 41 and the second winding wire 42 (conductor wire 41a) is not limited to aluminum and may be another conductive material such as copper. The insulating sheet 41b may be an insulating material, and may be insulating paper or a synthetic resin sheet. In the present embodiment, the first winding wire 41 is formed by spirally winding an insulating sheet 41b, which is an insulating paper, around the conductor wire 41a. The first winding 41 includes connection terminals 411 and 412 that are not covered with the insulating sheet 41b at both ends. The second winding 42 has connection terminals 421 and 422 at both ends.

  The connection terminal 411 of the first winding wire 41 and the connection terminal 421 of the second winding wire 42 are connected to one end side (left end side in FIG. 2) in the x direction of the winding part 4 and one z direction side (in FIG. 2). It extends from the upper side) to one side in the y direction (the front side in FIG. 2). The connection terminal 412 of the first winding 41 and the connection terminal 422 of the second winding 42 are connected to the other side in the x direction of the winding portion 4 (the right end side in FIG. 2) and the other side in the z direction (see FIG. 2), it extends to one side in the y direction. Further, the connection terminals 411, 412 and the connection terminals 421, 422 are respectively inserted into the cylindrical insulating member 45 for preventing a short circuit due to contact, and only the tip portions are exposed.

  The first winding 41 and the second winding 42 are spirally wound around the longitudinal portion 111 of the core 1 by so-called bifilar winding. That is, the first winding 41 and the second winding 42 are wound together in a single layer on the longitudinal portion 111 in a line in the x direction, and are wound so as to be alternately positioned in the x direction. There is. That is, the turns of the second winding 42 are positioned between the turns of the first winding 41. The first winding 41 and the second winding 42 are wound by so-called edgewise winding. That is, the first winding wire 41 and the second winding wire 42, which are rectangular wires having a rectangular cross section, stand upright with respect to the core 1 (the short side of the cross section is parallel to the x direction, and the long side of the cross section is x). It is wound so that it is orthogonal to the direction.

  As shown in FIG. 5, the connection terminal 421 of the second winding 42 is connected to the positive output terminal of the rectifier circuit 104, and the connection terminal 422 is connected to the positive input terminal of the inverter circuit 107. That is, the second winding 42 functions as a coil on the positive electrode side. On the other hand, the connection terminal 412 of the first winding 41 is connected to the negative output terminal of the rectifier circuit 104, and the connection terminal 411 is connected to the negative input terminal of the inverter circuit 107. That is, the first winding 41 functions as a coil on the negative electrode side. Since the first winding 41 and the second winding 42 are wound in the same direction by bifilar winding, in order to reverse the polarities of the positive side coil and the negative side coil, connection as shown in FIG. It has become.

  Next, the operation and effect of the reactor 105 according to this embodiment will be described.

  According to this embodiment, the first winding 41 is a covered wire in which the conductor wire 41a is covered with the insulating sheet 41b, and the second winding 42 is a bare wire not covered with the insulating sheet. Since the second winding 42 is not covered with the insulating sheet, heat dissipation is improved. The welding power supply device 100 is used for AC TIG arc welding, and since the positive polarity period is longer than the reverse polarity period, the current flows through the first winding 41 during the time when the current flows through the second winding 42. Longer than time. Therefore, the second winding 42 has a larger average value of the current than the first winding 41, and emits more heat. However, since the heat dissipation of the second winding 42 is improved, the temperature rise of the second winding 42 can be suppressed. Therefore, the temperature rise of the second winding 42 can be suppressed without increasing the cross-sectional area of the second winding 42. According to the inventor's experiment, when the second winding 42 is a covered wire similar to the first winding 41, the cross section of the second winding 42 is about 15 mm × 3 mm in order to use the output of 300 A. However, when the second winding 42 is a bare wire as in this embodiment, the cross section can be about 15 mm × 2 mm. That is, according to the present embodiment, the cross-sectional area of the second winding 42 can be reduced, so that the material cost can be suppressed. When the difference between the average values of the currents of the first winding wire 41 and the second winding wire 42 is small, the second winding wire 42 can have a smaller cross-sectional area due to improved heat dissipation. Therefore, the material cost can be suppressed.

  Further, since the first winding wire 41 is a covered wire, even if the first winding wire 41 and the second winding wire 42 are wound by bifilar winding, the conductor wire 41a of the first winding wire 41 and the second winding wire 42 are Can be insulated. The turns of the first winding 41 are located between the turns of the second winding 42. Therefore, the insulation between the turns of the second winding 42 can be secured. Furthermore, since the first winding 41 and the second winding 42 are wound by bifilar winding, the coupling between the first winding 41 and the second winding 42 is improved.

  Further, according to the present embodiment, the first winding 41 and the second winding 42 are wound by so-called edgewise winding. Therefore, heat dissipation can be improved when the rectangular wire is flat-wound and multi-layered, or when the round wire is multi-layered and has the same inductance. Further, the reactor 105 can be downsized.

  In addition, although the case where the first winding 41 is covered with the insulating sheet 41b has been described in the present embodiment, the present invention is not limited to this. The first winding 41 may be a conductor wire coated with synthetic resin or enamel. Further, although the case where the first winding 41 and the second winding 42 are rectangular wires and are wound by so-called edgewise winding has been described in the present embodiment, the present invention is not limited to this. For example, the first winding 41 and the second winding 42 may be wound by flat winding. The first winding 41 and the second winding 42 may be round wires having a circular cross section, or may have a square cross section or other shapes. Even in these cases, since the first winding 41 is a covered wire, the second winding 42 is a bare wire, and the first winding 41 and the second winding 42 are wound by bifilar winding, The heat dissipation of the second winding 42 can be improved while ensuring the insulation between the turns of the second winding 42.

  Further, although the case where the second winding 42 is a bare wire has been described in the present embodiment, the present invention is not limited to this. For example, the second winding 42 may be partially covered with an insulating coating. Even in this case, if the spirally wound portion has a portion not covered with the insulating coating, the heat dissipation of the second winding 42 is improved. Further, as shown in FIG. 6, the second winding 42 may be covered with an insulating coating thinner than the insulating sheet 41b of the first winding 41. In FIG. 6, the second winding 42 is a covered wire in which a conductor wire 42a, which is, for example, a rectangular wire made of aluminum, is covered with an insulating coating 42b thinner than the insulating sheet 41b. Even in this case, the heat dissipation of the second winding 42 is improved as compared with the first winding 41. Further, even if the second winding 42 is covered with an insulating film having the same thickness as the insulating sheet 41b of the first winding 41, if at least a part of the second winding 42 is covered with an insulating film thinner than the insulating sheet 41b, It is the same. In order to further improve the heat radiation of the second winding 42, it is desirable that the entire second winding 42 be a bare wire.

  Further, although the case where the conductor wire 41a of the first winding wire 41 and the second winding wire 42 have the same cross-sectional area has been described in the present embodiment, the present invention is not limited to this. The cross-sectional area of the conductor wire 41a and the cross-sectional area of the second winding 42 may be different. For example, the cross-sectional area of the second winding 42 may be made larger than the cross-sectional area of the conductor wire 41a to reduce the electric resistance and suppress the heat generation from the second winding 42. In this case, since heat generation from the second winding 42 is suppressed and heat radiation from the second winding 42 is improved, the temperature rise of the second winding 42 can be further suppressed.

  Although the case where the core 1 has a rectangular ring shape has been described in the present embodiment, the shape of the core 1 is not limited. The core 1 may have a circular ring shape, that is, a toroidal shape. Further, the core 1 may have, for example, an I type, an E type, or a shape obtained by combining these. The shape of the cross section of the core 1 is not limited to the rectangular shape, and may be, for example, a circular shape. Further, the presence or absence of gaps and the number of gaps are not limited. Furthermore, the reactor 105 may be a coreless type that does not include the core 1. Even in these cases, the heat dissipation of the second winding 42 can be improved while ensuring the insulation between the turns of the second winding 42.

  In the present embodiment, the welding power supply device 100 for TIG arc welding including the reactor 105 has been described, but the reactor 105 can also be used for other welding power supply devices. The reactor 105 can also be used for gas shielded arc welding such as plasma welding, MAG welding, and MIG welding. However, in the case of MAG welding, MIG welding, etc., the period of the reverse polarity is longer than the period of the positive polarity, so the average value of the current is larger on the negative electrode side. Therefore, the second winding 42 is connected to the negative side and the first winding 41 is connected to the positive side. That is, the second winding 42 may be connected to the side on which the average value of the current increases.

  The reactor and the welding power source device according to the present invention are not limited to the above-described embodiments. The specific configuration of each part of the reactor and the welding power source device according to the present invention can be modified in various ways.

100: welding power supply device, 105: reactor, 1: core, 41: first winding, 41a: conductor wire, 41b: insulating sheet, 42: second winding

Claims (5)

A first winding wound in a spiral,
A second winding spirally wound so that each turn is located between each turn of the first winding;
Equipped with
The first winding is composed of a conductor wire having an insulating coating formed thereon,
The second winding is composed of a conductor wire in which at least a part of a spirally wound portion has no insulating coating, or a conductive wire having an insulating coating, and , At least a portion of the insulating coating is thinner than the insulating coating of the first winding,
A reactor characterized by that. The second winding is a bare wire,
The reactor according to claim 1. The conductor wire of the first winding and the conductor wire of the second winding have different cross-sectional areas.
The reactor according to claim 1 or 2. A reactor according to any one of claims 1 to 3, comprising:
Welding power supply device characterized in that. The average value of the current flowing through the second winding is greater than the average value of the current flowing through the first winding,
The welding power source device according to claim 4.

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