JP2011044534A - Low-loss high-frequency reactor, transformer, and common mode choke coil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a parallel winding reactor, transformer and common mode choke coil with a winding structure having a low line capacitance and excellent in high-frequency characteristics, reducing eddy current loss originated from a leakage magnetic flux generated from near the gap, permitting the use of inexpensive materials, and reducing the number of manufacturing processes. <P>SOLUTION: The reactor, transformer and common mode choke coil each includes a coil 14 including wire blocks 17 each having a column of a plurality of round wires 8 with an insulating coat which are parallelly aligned in a row. The wire blocks 17 are cylindrically laminated and wound in a direction perpendicular to a magnetic body 10 with respect to the lengthwise direction in which the wire blocks 17 are parallelly aligned in a row. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

      The present invention relates to a reactor element used in a power conversion circuit or the like.

A power conversion device configured by a plurality of power switches and converting DC power into AC power by PWM control is used for an inverter for driving a motor, an uninterruptible power supply, and the like. In most cases, reactors are often used for power conversion devices using semiconductors. In particular, large power reactors are often used for power system power converters. This reactor has a large power loss among power converters, and attention is focused on reducing the loss of the reactor because of energy problems and CO2 reduction problems.
There are also many problems with electromagnetic noise generated by switching. A method for improving switching (Japanese Patent Laid-Open No. 2000-262066) has also been proposed and has attracted attention. In addition, a coil with good high frequency characteristics can be realized by reducing the stray capacitance of the reactor, and this proposal has also been made (Japanese Utility Model Publication No. 6-55212).

The reactor loss can be broadly divided into (1) copper loss, (2) iron loss, and (3) eddy current loss.
The copper loss in (1) is a loss due to the resistance value that varies depending on the amount of current flowing through the copper material and the frequency.
The iron loss in (2) is due to hysteresis loss in the magnetic body and eddy current loss in the core.
The eddy current loss in (3) is a loss caused by the eddy current flowing in the coil or the like due to the leakage flux of the reactor generated from the air gap. The phenomenon of eddy current loss has been known in the past, but there are many unexplained countermeasures.
Further, as for the stray capacitance of the reactor, if it is low stray capacitance, it is difficult to transmit a high frequency. Therefore, when it is configured with a common mode choke, electromagnetic noise is easily reduced. Also, when used as a reactor reactor, it is difficult to transmit high frequency, and therefore electromagnetic noise can be reduced by the reactor. Furthermore, since a reactor with a small stray capacitance is difficult to transmit high frequency, there is little loss during high frequency switching.
The wire used for these is a copper wire coated with an insulation coating, but the flat wire used for edgewise coils has a square cross section and has a problem that the insulation coating cannot be uniformly coated. The method is difficult and expensive, and the reliability is low. The round wire has a round cross section and has no corners, so that the insulation coating can be easily made uniform, so it is inexpensive and has high insulation reliability.

The edgewise reactors of FIGS. 1 and 2 have a large copper cross-sectional area.
As for the copper loss of (1), measures are taken to increase the cross-sectional area of the winding like an edgewise reactor, or to reduce the resistance value by using litz wire due to the skin effect in the case of high frequency.
Regarding the iron loss of (2), the idea to improve the loss by changing the iron (core) shape or increasing the cross-sectional area of the magnetic material has been devised.
As for the eddy current loss of (3), there is an example examined in a bobbin used particularly at a high frequency as described in JP-A-H7-302720.
Since eddy current loss occurs in the vicinity of the air gap, the bobbin that performs winding is formed in a convex shape at the time of bobbin molding in advance, and is devised not to perform winding on this part. However, this is a technology for small reactors that use bobbins. Technology for large reactors that do not use bobbins has not been developed yet.

In the configuration of FIGS. 1 and 2, the eddy current 4 easily flows due to the leakage magnetic flux 3 in the vicinity of the air gap 9.
In this case, since eddy current loss occurs frequently in the coil, the eddy current loss of (3) becomes large.
Since the conventional interlayer coil shown in FIG. 3 can be wound from the lower layer, this method of manufacturing has been conventionally adopted because it is very easy to manufacture especially in the case of a thick wire. However, although there is interlayer contact, the distance between terminals is close and stray capacitance increases, and although the distance between terminals is long in the edgewise coil used in the edgewise reactor of Figure 1, the windings are in surface contact with each other. Therefore, the stray capacitance is slightly large. In this case, the electromagnetic noise increases because the stray capacitance is large. Furthermore, the loss at the time of super-high frequency switching becomes large. Furthermore, when a flat wire is used as the wire, it is more difficult to coat the insulation coating than the insulation of the round wire, and it is necessary to make the insulation coating thicker. Moreover, since the shrinkage between the outside and inside is greatly different, the winding processing speed cannot be increased. In this case, the wire becomes expensive, and the winding processing speed cannot be increased. Further, the reliability of the insulating coating is lowered.

(Claim 1)
A reactor element including a coil having at least one magnetic body and a winding wound around the magnetic body at least once, wherein the winding is made of a round wire having an insulating coating, and the coil A reactor element formed by laminating a plurality of round wire rods constituting a wire block configured by arranging wires in parallel in a line in a cylindrical shape along the magnetic body in a direction perpendicular to the magnetic body It is characterized by being.

(Claim 2)
A reactor element including a coil having at least one magnetic body having two or more legs and a winding wound around each leg of the magnetic body at least once, wherein the winding has an insulation coating The coil has a direction in which the plurality of round wires constituting the wire block configured by arranging the windings in parallel in a line is perpendicular to each leg of the magnetic body. Laminated in a cylindrical shape along the legs of the magnetic body, the winding direction of the coil wound around the other leg is opposite to the winding direction of the coil wound around one leg of the magnetic body. It is a reactor element.

(Claim 3)
A reactor element including a coil having at least one magnetic body and a coil wound around a leg of the magnetic body at least three times, wherein the winding is made of a round wire having an insulating coating, The direction in which the plurality of round wires constituting the wire block configured by arranging the windings in parallel in a row is stacked in a cylinder shape along the legs of the magnetic body in a direction perpendicular to the legs of the magnetic body. In the middle of winding, the plurality of round wires are rearranged in the reverse order with respect to the order in which the plurality of round wires are arranged in the wire block, and then the wire blocks are wound in the vertical direction. It is the reactor element comprised by these.

In such a configuration, a wire block with round wires arranged in parallel is used, so the proposed product improves the loss compared to the eddy current loss in the case of a vertically wound flat wire such as an edgewise reactor. This is because the reactor with this winding structure can reduce the eddy current loss generated from the leakage magnetic flux in the air gap portion.
Further, compared to surface contact using a flat wire, when the main wire block is used, the stray capacitance can be reduced because the windings are in line contact. In particular, since there is less stray capacitance compared to an inter-layer coil, electromagnetic noise can be suppressed when used in a power converter. In addition, when this coil is used in a high-frequency power converter having a large loss due to stray capacitance, the effect of reducing the loss is great.
Since a round wire can be used without using a rectangular wire as the material, the material can be configured at low cost, and the winding processing speed can be increased, so that the cost can be reduced. In particular, compared to edgewise winding, a round wire can be used, so the material can be constructed at a low cost, and since the load on the insulation coating is small, the winding processing speed can be increased, so that it can be made inexpensive as with an interlayer winding coil. .
These effects can be obtained for transformers and common mode chokes, even when used in a reactor. For this reason, a low-cost, low-loss, low-noise product can be manufactured.

Configuration of a conventional edgewise reactor that is the subject of the present invention (one leg) Sectional view of a conventional edgewise reactor that is the subject of the present invention (one leg) Conventional Interlayer Coil Configuration Diagram Subject of the Present Invention Configuration of a conventional edgewise coil that is an object of the present invention Proposed coil configuration diagram in the first embodiment of the present invention Proposed reactor cross-sectional view (one leg) in the first embodiment of the present invention Sectional view of a conventional edgewise reactor subject to the present invention (two legs) Proposed reactor cross-sectional view (two legs) in the second embodiment of the present invention Sectional view of proposed reactor in the third embodiment of the present invention (one leg)

A first embodiment of the present invention will be described with reference to FIGS.

In FIGS. 5 and 6, reference numeral 8 denotes a round wire, 17 denotes a wire block, 6 denotes a winding start terminal 1, 7 denotes a winding end terminal 2, 10 denotes a ferrite core, 14 denotes a coil, and 9 denotes an air gap.
For the air gap, the central magnetic leg of the ferrite core is polished to provide a width, or a plurality of air gaps are provided.
The coil 14 is composed of a wire block 17 formed by arranging a plurality of round wires 8 having an insulating coating in parallel in a row.
The coil starts winding the wire block 17 from the terminal 1, winds a desired number of turns, and forms the terminal 2 at the end of winding.
Attach this coil to the middle leg of the ferrite core.
The present embodiment takes such a form.
The operation of the figure is as follows.
When a high-frequency current is conducted from the terminal 1 to the terminal 2, a leakage magnetic flux 3 in the air gap 9 is generated. In the case where the copper material of the magnetic path of the leakage flux 3 is a conventional rectangular wire edgewise reactor as shown in FIG. 2, the eddy current loop is large and the flow is easy and the loss is large. Therefore, the eddy current loop becomes small. As a result, the eddy current is reduced and the loss is reduced.
The stray capacitance between the terminal 1 and the terminal 2 is a line contact in the case of the round wire of this method compared with the surface contact in the case of the conventional rectangular edgewise coil of FIG. Becomes smaller. In this case, a round wire that is cheaper than a rectangular wire can be used.

A second embodiment of the present invention will be described with reference to FIGS.
5 and 8, reference numeral 10 denotes a cut core of a silicon steel plate, 14 denotes a coil, 6 winding start terminals 1, 7 winding end terminals 2 and 9 correspond to air gaps.
The air gap uses the same air gap material (Nomex, Lumirror, etc.) for the two magnetic legs of the cut core to provide an air gap width.
The coils 1 and 24 of 24 and 25 are constituted by a wire block 17 constituted by arranging a plurality of round wires 8 having an insulating coating in parallel in a line.
Similar to the coil 1 laminated in a cylindrical shape and wound in the counterclockwise direction, the coil 2 is laminated in the cylindrical shape and wound in the clockwise direction.
In the overall configuration, the coil 1 is configured on the first leg 20 of the magnetic material, and the coil 2 is configured on the second leg 21 of the magnetic material.
The present embodiment takes such a form.
The operation of the figure is as follows.
As in the first embodiment, eddy current loss is reduced.
As in the first embodiment, electromagnetic noise can be suppressed.
As in the first embodiment, an inexpensive round wire can be used.

A third embodiment of the present invention will be described with reference to FIG.
5 and 9, 10 corresponds to a ferrite core, 14 corresponds to a coil, and 9 corresponds to an air gap. The configuration of the magnetic body is the same as that of the first embodiment.
The coils 1 and 2 are constituted by a wire block 17 constituted by arranging a plurality of round wires 8 having an insulating coating in parallel in a line.
The coil starts winding the wire block 17 from the terminal 1, winds a desired number of turns, and forms the terminal 2 at the end of winding.
In the coil 1, the magnetic material side portion of the wire block is replaced at the replacement point 15 outside the coil in the coil 2. The overall configuration is the same as in the first embodiment.
The present embodiment takes such a form.
The operation of the figure is as follows.
As in the first embodiment, eddy current loss is reduced.
As in the first embodiment, electromagnetic noise can be suppressed.
As in the first embodiment, an inexpensive round wire can be used.

1 Edgewise coil 3 Leakage magnetic flux 4 Eddy current 5 Insulation coating 6 Terminal 1 (winding start side)
7 Terminal 2 (winding end side)
8 Round wire 9 Air gap 10 Magnetic body 12 Central magnetic leg 14 Coil 15 Replacement point 17 Wire block 20 First leg 21 of magnetic body Second leg 24 of magnetic body First coil 25 Second coil

Claims (7)

A reactor element including a coil having at least one magnetic body and a winding wound around the magnetic body at least once, wherein the winding is made of a round wire having an insulating coating, and the coil is the winding The windings constituting the wire block constituted by arranging the wires in parallel in a line are arranged in a cylindrical shape along the magnetic body in a direction perpendicular to the magnetic body. Reactor element.   A reactor element including at least one magnetic body having two or more legs and a coil having a winding wound around each leg of the magnetic body at least once, wherein the winding has an insulation coating The coil includes a wire block configured by arranging the windings in parallel in a row, and the winding is arranged in a direction perpendicular to the legs of the magnetic body. It is configured such that it is laminated in a cylindrical shape along the leg of the body, and the winding direction of the coil wound around the other leg is reversed with respect to the winding direction of the coil wound around one leg of the magnetic body. Characteristic reactor element.  A reactor element including at least one magnetic body and a coil having a winding wound around a leg of the magnetic body at least three times, wherein the winding is made of a round wire having an insulating coating, The winding arrangement direction of the wire block configured by arranging the windings in parallel in a row is laminated in a cylindrical shape along the legs of the magnetic body in a direction perpendicular to the legs of the magnetic body. In the middle of winding, the plurality of round wire rods are rearranged in the reverse order with respect to the sequence of the plurality of round wire rods of the wire block, and then the wire block is wound in the vertical direction. A reactor element characterized by being configured. (Known explanation)
A transformer constituted by a coil according to claim 1. (Known explanation)
A transformer constituted by a coil according to claim 3. (Known explanation)
A common mode choke constituted by a coil according to claim 1. (Known explanation)
A common mode choke constituted by a coil according to claim 2.