WO2012017616A1

WO2012017616A1 - Reactor

Info

Publication number: WO2012017616A1
Application number: PCT/JP2011/004195
Authority: WO
Inventors: 拓志地道; 松田　哲也
Original assignee: 三菱電機株式会社
Priority date: 2010-08-06
Filing date: 2011-07-26
Publication date: 2012-02-09
Also published as: JPWO2012017616A1; JP5310952B2

Abstract

In order to obtain a reactor that is capable of reducing the eddy-current loss at a winding wire caused by means of the leakage flux from the gap of an iron core, the reactor is provided with: iron cores (11, 12) which have at least one pair of leg portions (14p, 14q) facing one another and which are formed with a gap (13) by means of the pair of leg portions (14p, 14q); and winding wires (1, 2) which are wound around the pair of leg portions (14p, 14q) along the direction in which the pair of leg portions (14p, 14q) extend and which are multiply wound so as to overlap with one another in a direction that is roughly perpendicular to the aforementioned direction in which the pair of leg portions (14p, 14q) extend. In a region surrounding the gap, the innermost turn of the winding wires (1, 2) is constituted by a litz wire (1) in which multiple wires are twisted together, and the outermost turn of the winding wires (1, 2) is constituted by a single wire (2).

Description

Reactor

The present invention relates to a reactor that is connected to a power conversion device or incorporated in a power conversion device.

The reactor is used to connect the power conversion device to a voltage source such as a system power supply or a solar battery. When a voltage type power converter is directly connected to another voltage source, a large current flows due to the potential difference, and the power converter is damaged or an abnormality occurs in the voltage source. Therefore, the voltage type power converter is connected to a voltage source via a reactor. In some cases, the voltage applied to the reactor is adjusted to control the current, and active power and reactive power are exchanged between the power converter and the voltage source.

On the other hand, an increase in hysteresis loss that occurs in the core of the reactor as the frequency of the power converter increases, and when the high-frequency current generated in the power converter flows in the winding of the reactor, the skin where the current density increases on the surface of the winding An increase in copper loss due to the effect may be a problem. In order to solve such problems, there is a winding structure in which a main winding having a small resistance with respect to a fundamental current of a flowing current and an auxiliary winding having a small resistance with respect to a high-frequency current are wound around an iron core in parallel. (For example, refer to Patent Document 1). Further, there is a winding structure in which a single wire and a litz wire are wound around a bobbin or a core such as a transformer or a choke and connected in parallel (see, for example, Patent Document 2).

JP-A-5-243060 (pages 3-4, FIGS. 1 and 3) Japanese Patent Laid-Open No. 2001-297922 (page 2-3, FIGS. 1 and 3)

In a conventional reactor, when a gap is formed in the iron core and a winding structure is also formed around the gap, eddy current loss occurs in the winding due to leakage magnetic flux from the gap, and power loss increases. was there. Then, there is a problem that resistance loss increases when the winding is made thin to reduce eddy current loss.

The present invention has been made to solve the above-described problems, and obtains a reactor that can achieve both a reduction in eddy current loss in a winding and a reduction in winding resistance caused by leakage magnetic flux from a gap in an iron core. It is.

A reactor according to the present invention has at least one pair of legs facing each other, an iron core in which a gap is formed by the pair of legs, and a pair of legs along the extending direction of the pair of legs. And a winding that is wound in multiple layers so as to overlap in a direction substantially perpendicular to the extending direction, and in the region surrounding the gap, the innermost circumference of the winding is a litz in which a number of strands are twisted together It is comprised with a wire | line, and the outermost periphery of a coil | winding is comprised with a single wire.

In this invention, in the region surrounding the gap of the iron core, the innermost circumference of the winding is composed of litz wires in which a number of strands are twisted, and the outermost circumference of the winding is composed of a single wire. It is possible to obtain a reactor that can achieve both a reduction in eddy current loss in a winding caused by leakage magnetic flux and a reduction in winding resistance.

It is a circuit diagram which shows an example of the power converter device to which the reactor in Embodiment 1 of this invention is applied. It is sectional drawing of the reactor in Embodiment 1 of this invention. It is a circuit diagram which shows the coil connection of the reactor shown in FIG. 2 in Embodiment 1 of this invention. It is a figure which shows a mode that the leakage magnetic flux of the reactor shown in FIG. 2 in Embodiment 1 of this invention flows. It is sectional drawing of another reactor in Embodiment 1 of this invention. It is a circuit diagram which shows the coil connection of the reactor shown in FIG. 5 in Embodiment 1 of this invention. It is a figure which shows a mode that the leakage magnetic flux of the reactor shown in FIG. 5 in Embodiment 1 of this invention flows. It is sectional drawing of the reactor in Embodiment 2 of this invention. It is a figure which shows a mode that the leakage magnetic flux of the reactor shown in FIG. 8 in Embodiment 2 of this invention flows. It is sectional drawing of another reactor in Embodiment 2 of this invention. It is sectional drawing of the reactor in Embodiment 3 of this invention. It is a circuit diagram which shows the coil connection of the reactor shown in FIG. 11 in Embodiment 3 of this invention. It is a circuit diagram which shows another coil | winding connection of the reactor shown in FIG. 11 in Embodiment 3 of this invention. It is a circuit diagram which shows an example of the power converter device to which the reactor in Embodiment 3 of this invention is applied. It is sectional drawing of another reactor in Embodiment 3 of this invention. It is a circuit diagram which shows the coil connection of the reactor shown in FIG. 15 in Embodiment 3 of this invention. It is a circuit diagram which shows another coil | winding connection of the reactor shown in FIG. 15 in Embodiment 3 of this invention. It is sectional drawing of the reactor in Embodiment 4 of this invention. It is sectional drawing of another reactor in Embodiment 4 of this invention. It is sectional drawing of the reactor in Embodiment 5 of this invention. FIG. 6 is a cross-sectional view showing an example of a winding arrangement in the first to fifth embodiments of the present invention.

Embodiment 1 FIG.
FIG. 1 is a circuit diagram showing an example of a power converter to which the reactor of the present invention is applied. In FIG. 1, the power conversion apparatus includes a power converter 104, a reactor 103, and a capacitor 102. The power converter 104 is connected to the three-phase system power supply 101 via the reactor 103. The reactor 103 generally uses three single-phase reactors, but a three-phase reactor in which three phases are integrated may be used.

For example, when the power converter 104 is a voltage type power converter and is connected to the three-phase system power supply 101 without passing through the reactor 103, an overcurrent caused by a potential difference between the power converter 104 and the three-phase system power supply 101 As a result, the semiconductor elements constituting the power converter 104 are destroyed or the power system is adversely affected. For this reason, when the power converter 104 is a voltage type, it is essential to connect the reactor 103. When reactor 103 is used, it may be connected in combination with capacitor 102 such as a filter capacitor.

In FIG. 1, the current flowing through the reactor 103 includes a commercial frequency current component of the three-phase system power supply 101 and a current component in a frequency (switching frequency) region in which the semiconductor elements constituting the power converter 104 perform switching. Including. For example, the commercial frequency is a low frequency of 50 Hz or 60 Hz, and the switching frequency is generally a high frequency of 1 kHz or more. The reactor of the present invention is assumed to be used in such an application that both low-frequency component current and high-frequency component current flow, and a power converter that performs DC / AC conversion as shown in FIG. It may be used as a reactor 103 connected to the output terminal 104, or may be used as a reactor connected to an input terminal or an output terminal of a power converter that performs AC / AC conversion, or performs AC / DC conversion. You may use as a reactor connected to the input terminal of a power converter, and you may use as a reactor connected to the input terminal which performs DC / DC conversion, or an output terminal. The power converter may be a two-level converter that outputs a two-level voltage as shown in FIG. 1 or a multi-level converter that outputs a voltage of three or more levels.

Further, a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) may be used as a semiconductor element constituting the power converter 104, or an IGBT (Insulated Gate Bipolar Transistor) or IEGT (Injected Transient Transistor). Other semiconductor elements such as a GCT (Gate Committed Turn-off) thyristor and JFET (Junction Field Effect Transistor) may be used.

As a material of the semiconductor element constituting the power converter 104, silicon can be generally used, but a wide band gap semiconductor material having a wider band gap than silicon, for example, silicon carbide, gallium nitride, diamond, or the like. May be used. In a power converter using a wide band gap semiconductor material, switching loss can be reduced as compared with a power converter using silicon, and the power converter is driven at a high frequency. On the other hand, as power converters are driven at higher frequencies, the hysteresis loss that occurs in the core of the reactor increases, and when the high-frequency current generated by the power converter flows through the reactor windings, the skin effect occurs and copper loss occurs. Increase. That is, by using the wide band gap semiconductor material, the power loss in the power converter is reduced, while the loss in the reactor is increased. Since the reactor of the present invention can reduce the loss when the power converter is driven at a high frequency, even when a wide band gap semiconductor material is used for the power converter, the characteristics of the wide band gap semiconductor material are utilized to reduce the loss. A lossy power conversion device can be obtained.

FIG. 2 is a cross-sectional view of the reactor in the first embodiment of the present invention. FIG. 3 is a circuit diagram showing winding connection of the reactor shown in FIG. In FIG. 2, a reactor 10 is arranged so that two E-shaped iron cores 11 and E-shaped iron cores 12 made of a magnetic material face each other, and a winding 1 and a winding 2 are provided on a central leg 14 provided with a gap 13. It is constructed by being wound (wrapped). Winding 1 and winding 2 are each a single winding among the windings wound in multiple. The center leg 14 is composed of a pair of opposing

leg portions

14p and 14q, and a gap 13 is formed between the pair of

leg portions

14p and 14q. In the embodiment of the present invention, the gap 13 is an air gap, but a material having a low magnetic permeability may be provided in the gap portion. Magnetic materials for

E-shaped iron cores

11 and 12 include silicon steel plates, steel plates with 6.5% silicon content (Super E core), ferrite cores, amorphous cores, dust cores made by mixing iron, aluminum and silicon, and nanocrystals A soft magnetic material such as fine-met core can be used. In addition, although the two iron cores of

E-shaped iron cores

11 and 12 are used, this is to facilitate winding processing, and an iron core in which the

E-shaped iron cores

11 and 12 are integrated may be used. . Furthermore, the shape of the iron core is not limited, and a feature is that a gap is included in the legs of the iron core to be wound.

The winding 1 and the winding 2 are wound around the central leg 14 with the same number of turns C turns along the extending direction of the central leg 14 (a set of

leg portions

14p and 14q). Then, the winding 1 and the winding 2 are wound in a multiple manner so as to overlap in a direction substantially perpendicular to the extending direction. The winding 1 is wound on the inner peripheral side close to the center leg 14. The winding 2 is wound on the outer peripheral side far from the central leg 14. As shown in FIG. 3, the ends of the

windings

1 and 2 are connected in parallel in the winding direction in which the inductances of both the

windings

1 and 2 are not lost, that is, the inductance is not impaired. In FIG. 3, a dot (●) represents the polarity of each winding. The length of the gap 13 and the number of turns C-turn are determined according to a desired inductance value. For example, the gap length is determined to be 3 mm and the number of turns is determined to be 16 turns.

A characteristic point of the present embodiment is that the winding 1 wound on the inner peripheral side close to the center leg 14 is composed of a litz wire obtained by twisting a large number of thin wire elements, and the outer peripheral side thereof. The winding 2 to be wound around is composed of a single wire, and the winding 1 and the winding 2 are wound twice. The wire diameter of the single wire of the winding 2 may be the same as the finished diameter of the litz wire of the winding 1. For example, the winding 1 uses a litz wire obtained by twisting 38 strands having a wire diameter of 0.3 mm and whose outer peripheral surface is insulated. A tetron may be wound around the outer periphery of the litz wire in order to keep the finished cross section circular. In this case, since the finished diameter of the litz wire of the winding 1 is about 2.4 mm, a single wire of 2.4 mm is used for the winding 2. In FIG. 2, since the winding is a double winding, in the region surrounding the gap 13, the innermost circumference of the winding is constituted by a litz wire (winding 1), and the outermost circumference of the winding is a single wire (winding). Line 2). In FIG. 2, in particular, the winding 1 and the winding 2 are composed of a litz wire (winding 1) in the innermost circumference of the winding in all regions surrounding the gap 13 and the central leg 14. The outermost periphery of the wire is composed of a single wire (winding 2).

FIG. 4 is a diagram illustrating a state in which the leakage magnetic flux of the reactor flows, and illustrates the magnetic flux 15 while paying attention to the periphery of the gap 13 in FIG. Since a magnetic material having a high non-permeability with respect to vacuum is used for the iron core portion other than the gap 13, almost all the magnetic flux 15 passes through the iron core (the

leg portions

14p and 14q in FIG. 4). The magnetic flux 15 passing through the iron core tends to cause a current to flow in the iron core in a direction that prevents the magnetic flux 15 according to Lenz's law. However, a laminated structure of thin steel plates whose surroundings are insulated with respect to the magnetic flux passing method as represented by the surface direction, such as silicon steel plates, or fine granular magnetic materials such as dust cores are insulated on the iron core. It is known to use a compacted structure. By adopting such a structure and reducing the area in the direction in which this eddy current tends to flow, eddy current loss is reduced to a negligible range.

On the other hand, as shown in FIG. 4, the magnetic flux in the gap 13 portion does not become linear along the extending direction of the iron core but spreads to the portion where the winding is wound. In a conventional reactor using only a single wire as a winding as in the prior art, when the magnetic flux 15 is linked to the winding, a current flows through the winding in a direction in which the magnetic flux 15 is to be blocked. For example, in the case of a single wire having a wire diameter of 2.4 mm, the eddy current loss due to the leakage magnetic flux is large, and thus eddy current loss cannot be ignored. Therefore, in the present embodiment, a litz wire in which a number of thin strands are twisted is used as the winding 1 that is wound on the inner peripheral side where leakage magnetic flux in the region surrounding the gap 13 is significantly interlinked. In the litz wire, the outer peripheral surface of the strand is insulated. For example, with a litz wire using a strand of 0.3 mm, the eddy current flow area is narrow when the leakage magnetic flux is interlinked, so it is possible to reduce the eddy current loss to a negligible range.

In this way, Litz wire has the advantage of reducing eddy current loss due to leakage magnetic flux, but the space factor, which is the proportion of the conductor in the cross section of the winding, is reduced by a structure in which a number of thin strands are twisted. To do. For this reason, in the commercial frequency region such as 50 Hz or 60 Hz, the winding resistance of the litz wire becomes larger than the winding resistance of the single wire having the same finished diameter, and there is a disadvantage that the resistance loss increases. Therefore, in the present embodiment, a single wire is used as the winding 2 that is wound around the outer peripheral side where there is little leakage magnetic flux in the region surrounding the gap 13, and the winding resistance in the commercial frequency region is reduced.

In the description with reference to FIG. 2 described above, the entire winding is a double winding in which the winding 1 and the winding 2 are wound in a single layer, but multiple windings of three or more windings may be used. FIG. 5 is a cross-sectional view of another reactor according to Embodiment 1 of the present invention. FIG. 6 is a circuit diagram showing winding connection of the reactor shown in FIG. Moreover, FIG. 7 is a figure which shows a mode that the leakage magnetic flux of the reactor shown in FIG. 5 flows. The difference between the reactor 20 shown in FIG. 5 and the reactor 10 shown in FIG. 2 is the configuration of the winding. In FIG. 5, the entire winding is configured by winding n windings having the same number of turns C turns. In this case, the x-fold (x: integer and 1 ≦ x <n) windings (winding 1 to winding j in FIG. 5) wound on the inner peripheral side close to the center leg 14 have a thin wire diameter. The winding of y layers (y = nx) wound around the outer periphery of the litz wire (a winding k to the winding n in FIG. 5) is a single wire. It is configured and wound as a whole in n layers (n = x + y). The diameter of the single wire from winding k to winding n may be the same as the finished diameter of the litz wire from winding 1 to winding j. As shown in FIG. 6, the ends of winding 1 to winding n are connected in parallel in the winding direction that does not impair the inductance. In FIG. 5, in the region surrounding the gap 13, the innermost circumference of the winding is constituted by a litz wire (winding 1), and the outermost circumference of the winding is constituted by a single wire (winding n).

By increasing the number of multiple turns n of the entire winding, the space where the winding in the iron core can be applied can be used effectively, so that the winding resistance can be further reduced. Further, as shown in FIG. 7, if the number of multiple turns x from the winding 1 to the winding j using the litz wire is adjusted according to the spread of the leakage magnetic flux from the gap 13, the winding in the high frequency region The reduction of the eddy current loss in the portion and the reduction of the winding resistance in the low frequency region can both be achieved, and a reactor with a lower loss can be realized.

As described above, a single wire and a litz wire in which a number of strands are twisted together are wound in multiple layers, and the innermost circumference of the entire winding is composed of a litz wire in the region surrounding the gap 13, and the outermost circumference of the entire winding is Since it is constituted by a single wire, it is possible to obtain a reactor that can achieve both a reduction in eddy current loss and a reduction in winding resistance in the winding caused by leakage magnetic flux from the gap 13 of the

iron cores

11 and 12.

Embodiment 2. FIG.
FIG. 8 is a cross-sectional view of the reactor in the second embodiment of the present invention. Moreover, FIG. 9 is a figure which shows a mode that the leakage magnetic flux of the reactor shown in FIG. 8 flows. Similarly to the reactor according to the first embodiment, the reactor according to the present embodiment is used for an application in which both a low-frequency component current and a high-frequency component current flow. In FIG. 8, similarly to the first embodiment, a reactor 30 is arranged so that two E-shaped iron cores 11 and E-shaped iron cores 12 formed of a magnetic material face each other. The winding 1a and the winding 2a are wound (wound). The center leg 14 is composed of a pair of opposing

leg portions

14p and 14q, and a gap 13 is formed between the

leg portions

14p and 14q.

The winding 1a and the winding 2a are wound around the central leg 14 along the extending direction of the central leg 14 with the same number of turns C. The winding 1a uses a litz wire obtained by twisting a number of strands having a thin wire diameter, and the winding 2a uses a single wire having the same diameter as the finished diameter of the litz wire of the winding 1a. The difference from the first embodiment is how to wind the litz wire and the single wire around the iron core. In the first embodiment, the litz wire is disposed on the inner peripheral side close to the central leg 14 and the single wire is disposed on the outer peripheral side in the entire extending direction of the central leg 14, that is, as a configuration of the entire winding. In the present embodiment, at least in the region surrounding the gap, the litz wire is disposed on the inner peripheral side close to the center leg 14 and the single wire is disposed on the outer peripheral side, but in the region other than the region surrounding the gap, There is no such limitation, and the winding 1a and winding 2a of the same line type as in the first embodiment are arranged so as to be replaced in the middle along the extending direction of the central leg 14. That is, in a part of the region surrounding the pair of

leg portions

14p and 14q, the innermost circumference is constituted by a single wire (winding 2a) and the outermost circumference is constituted by a litz wire (winding 1a).

A specific example will be described with reference to FIG. The first turn that is the beginning of winding of the winding 1a and winding 2a is arranged so that the winding 1a is on the outer peripheral side and the winding 2a is on the inner peripheral side. When the number of turns has passed C / 4 turn (four turns in FIG. 8), the winding 1a is switched to the inner peripheral side and the winding 2a is switched to the outer peripheral side. When the number of turns has passed 3C / 4 turns (12 turns in FIG. 8), the winding 1a is switched to the outer peripheral side and the winding 2a is switched to the inner peripheral side. In addition, when C / 4 turn or 3C / 4 turn does not become an integer, replacement may be performed after the number of turns having values near C / 4 or 3C / 4. As in the first embodiment, as shown in FIG. 3, the ends of the winding 1a and the winding 2a are connected in parallel in the winding direction that does not impair the inductance of both the winding 1a and the winding 2a.

In this way, by applying a winding method to replace the single wire and the litz wire, the litz wire (winding 1a), which is a single winding of the double-wound winding, and the central leg 14 are wound. The average distance between the center line 14 c and the center line 14 c between the single line (winding 2 a) that is the other single winding of the windings wound twice and the center line 14 c of the center leg 14. It can be approximately equal to the average distance. For this reason, the inductance of the winding 1a and the inductance of the winding 2a can be made equal. Here, the center line 14c of the central leg 14 corresponds to a line extending in the extending direction of the central leg 14 by connecting the centers of the surfaces of the leg 14p and the leg 14q that face each other. The average distance between the single winding and the center line 14c is obtained by calculating the distance between the winding and the center line 14c for each turn of the single winding and averaging these distances. It is.

When the inductance of the winding 1a and the inductance of the winding 2a are not equal, the voltage drop of the winding 1a and the voltage drop of the winding 2a are equal between the

windings

1a and 2a. A large circulating current will flow. As a result, the copper loss increases. However, such a circulating current can be suppressed by applying a winding method that equalizes the inductance of the winding 1a and the inductance of the winding 2a as in the present embodiment. As shown in FIG. 9, in the region surrounding the gap 13, as in the first embodiment, the winding 1 a using a litz wire is arranged for the winding on the inner peripheral side where the leakage magnetic flux is remarkably linked. Therefore, the eddy current loss in the winding part can also be reduced.

In FIG. 8, the single wire and the litz wire are interchanged twice, but the litz wire (winding 1 a), which is a single winding of the double-wound winding, and the center leg 14 are used. The average distance between the center line 14c and the center line 14c between the single wire (winding 2a), which is another single winding of the multiple windings, and the center line 14c of the center leg 14 If the winding 1a using the litz wire in the region surrounding the gap 13 is substantially equal to the average distance and is arranged on the inner peripheral side close to the central leg 14, the number of times the single wire and the litz wire are replaced, Regardless of, the same effect can be obtained.

In the description with reference to FIG. 8 described above, the entire winding is a double winding, but multiple windings of triple or more may be used. FIG. 10 is a cross-sectional view of another reactor in the second embodiment of the present invention. As shown in FIG. 10, the entire winding of the reactor 40 is composed of n windings of the same number of turns C turns, and as shown in FIG. You may connect in parallel by the winding direction which is not impaired. Even in this case, the average distance between the winding 1a, which is a single winding of the multiple windings, and the center line 14c of the central leg 14 is equal to each single winding other than the winding 1a. Winding is performed so that the average distance between the winding (winding 2a (not shown) to winding na) and the center line 14c of the center leg 14 is substantially equal. Further, in the region surrounding the gap 13, the x-fold winding using the litz wire (winding 1 a to winding ja) is arranged on the inner peripheral side close to the center leg 14 and the y-fold using the single wire is used. The windings (winding ka to winding na) are replaced with x-folding windings (winding 1a to winding ja) using a litz wire. During the replacement, the winding 1a wound around the innermost periphery in the region surrounding the gap 13 is wound around the outermost periphery. The winding na wound around the outermost periphery in the region surrounding the gap 13 is wound around the innermost periphery.

When the number of parallel turns is increased by adjusting the number of multiple turns x in this way, the effect of reducing the eddy current loss due to the leakage magnetic flux from the gap 13 and the effect of suppressing the circulating current due to the difference in inductance are maintained, and the eddy current in the winding portion is maintained. The space for winding can be effectively used while reducing the loss, and the winding resistance can be further reduced.

Embodiment 3 FIG.
FIG. 11 is a cross-sectional view of the reactor in the third embodiment of the present invention. FIG. 12 is a circuit diagram showing winding connection of the reactor shown in FIG. FIG. 13 is a circuit diagram showing another winding connection of the reactor shown in FIG. The second embodiment is different from the first embodiment in that two U-shaped iron cores are arranged so as to face each other to form leg portions having two gaps, and windings are wound around the respective leg portions. The winding method for one leg is the same as in the first embodiment. In the present embodiment, similarly to the first and second embodiments, a reactor used for an application in which both a low-frequency component current and a high-frequency component current flow is assumed.

11, the reactor 50 is arranged so that two U-shaped iron cores 51 and U-shaped iron cores 52 formed of a magnetic material face each other while ensuring

gaps

53a and 53b. A winding A1 and a winding A2 are wound around a first side leg 54a provided with a gap 53a. The first side leg 54a includes a pair of opposing leg portions 54ap and 54aq, and a gap 53a is formed between the leg portions 54ap and 54aq. A winding B1 and a winding B2 are wound around a second side leg 54b provided with a gap 53b. The second leg 54b is composed of a pair of opposing leg portions 54bp and 54bq, and a gap 53b is formed between the leg portions 54bp and 54bq. That is, the windings A1 and A2 and the windings B1 and B2 are wound around the leg portions 54ap and 54aq and the leg portions 54bp and 54bq, which are a plurality of sets of leg portions, respectively.

In the embodiment of the present invention, the

gaps

53a and 53b are air gaps, but a material having a low magnetic permeability may be provided in the gap portions. Magnetic materials for

U-shaped iron cores

51 and 52 include silicon steel plates, steel plates with 6.5% silicon content (Super E core), ferrite cores, amorphous cores, dust cores made by mixing iron, aluminum and silicon, and nanocrystals A soft magnetic material such as fine-met core can be used. The shape of the iron core is not limited and is characterized in that a gap is included in the legs of the iron core to be wound.

In the reactor 50 according to the present embodiment, the windings A1 and A2 are provided on the first side leg 54a and the second side leg 54b is provided in the same manner as the winding method around the reactor 10 shown in the first embodiment. Winding B1, B2 is wound around. Winding A1 and winding A2 are wound with the same number of turns C around the first side leg 54a along the extending direction of the first side leg 54a. The winding A1 is wound on the inner peripheral side close to the first side leg 54a. The winding A2 is wound on the outer peripheral side far from the first side leg 54a. Similarly, the winding B1 and the winding B2 are wound around the first side leg 54b with the same number of turns C along the extending direction of the first side leg 54b. The winding B1 is wound on the inner peripheral side close to the first side leg 54b. The winding B2 is wound on the outer peripheral side far from the first side leg 54b. Each of the windings A1, A2, B1, and B2 is a single winding among the windings wound in multiple. As shown in FIG. 12, the ends of the windings A1, A2, B1, and B2 are connected in parallel in a winding direction that does not impair the inductance of each winding.

As in the first embodiment, the winding A1 wound on the inner peripheral side close to the first side leg 54a is composed of a litz wire obtained by twisting many strands having a thin wire diameter, and on the outer peripheral side thereof. The winding A2 to be wound is composed of a single wire, and the winding A1 and the winding A2 are wound twice. The wire diameter of the single wire of the winding A2 may be the same as the finished diameter of the litz wire of the winding A1. Similarly, the winding B1 wound on the inner peripheral side close to the second side leg 54b is formed of a litz wire obtained by twisting a large number of strands having a thin wire diameter, and is wound around the outer peripheral side. Is composed of a single wire, and windings B1 and B2 are wound twice. The wire diameter of the single wire of the winding B2 may be the same as the finished diameter of the litz wire of the winding B1. In FIG. 11, since the winding is a double winding, in the region surrounding the gap 53a, the innermost circumference of the winding is constituted by a litz wire (winding A1), and the outermost circumference of the winding is a single wire (winding). Line A2), and in the region surrounding the gap 53b, the innermost circumference of the winding is constituted by a litz wire (winding B1), and the outermost circumference of the winding is constituted by a single line (winding B2).

As in the first embodiment, in the region surrounding the

gaps

53a and 53b, by configuring the innermost circumference of the winding with a litz wire, eddy current loss due to leakage magnetic flux can be reduced, and the outermost circumference of the winding is made with a single wire. By configuring, winding resistance in the commercial frequency region can be reduced. In addition to such an effect, in the present embodiment, the number of windings in parallel can be increased, so that the winding resistance can be further reduced.

Further, the windings A1 and A2 wound around the first side leg 54a and the windings B1 and B2 wound around the first side leg 54b are not connected in parallel, as shown in FIG. , B1 and B2 may be connected. That is, each of the windings A1 and A2 and the windings B1 and B2 is wound around each of a plurality of

side legs

54a and 54b (a plurality of sets of leg portions 54ap and 54aq and leg portions 54bp and 54bq). The windings that are rotated and wound around the

respective side legs

54a and 54b (legs of each pair) are connected in parallel in a direction that does not impair the inductance. By connecting the windings A1 and A2 and the windings B1 and B2 in this manner, in the single-phase power converter as shown in FIG. 111 can be connected.

Although FIG. 11 shows the case where the winding is wound twice, the winding may be triple or more. FIG. 15 is a cross-sectional view of another reactor according to Embodiment 3 of the present invention. FIG. 16 is a circuit diagram showing the winding connection of the reactor shown in FIG. FIG. 17 is a circuit diagram showing another winding connection of the reactor shown in FIG. The difference between the reactor 60 shown in FIG. 15 and the reactor 50 shown in FIG. 11 is the configuration of the winding. In FIG. 15, the winding method for the pair of opposing leg portions is the same as in FIG. 5 of the first embodiment. In FIG. 15, the whole winding is configured by winding n turns with the same number of turns C turns. In this case, x-fold (x: integer and 1 ≦ x <n) windings (from winding A1 to winding Aj, winding B1 in FIG. 15) wound on the inner peripheral side close to the

side legs

54a, 54b. To winding Bj) is composed of a litz wire formed by twisting a number of strands having a thin wire diameter, and a y-fold (y = nx) winding (winding in FIG. 15) wound around the outer periphery thereof. The windings Ak to An and windings Bk to Bn) are formed of a single wire, and are wound n times (n = x + y) as a whole. The wire diameter of the single wire from the winding Ak to the winding An and the winding Bk to the winding Bn may be the same as the finished diameter of the litz wire from the winding A1 to the winding Aj and from the winding B1 to the winding Bj. . As shown in FIG. 16, the ends of the windings A1 to Bn are connected in parallel in a winding direction that does not impair the inductance.

Further, the windings A1 to An wound around the first side leg 54a and the windings B1 to Bn wound around the first side leg 54b are not connected in parallel, but are wound as shown in FIG. To An and B1 to Bn may be connected. By connecting the windings in this way, as described above, in the single-phase power converter as shown in FIG. 14, the power converter 114 and the single-phase system power supply 111 are connected by one reactor 113. It is possible.

By increasing the number of multiple turns n of the entire winding, the space in which the winding in the iron core can be applied can be used effectively, so that the winding resistance can be further reduced and the leakage magnetic flux from the

gaps

53a and 53b can be expanded. Accordingly, if the number of multiple turns x from the winding A1 to the winding Aj using the litz wire (from the winding B1 to the winding Bj) is adjusted, the eddy current loss of the winding portion in the high frequency region can be reduced. Moreover, it is possible to achieve both a reduction in winding resistance in the low frequency region and to realize a reactor with lower loss.

Embodiment 4 FIG.
FIG. 18 is a cross-sectional view of the reactor in the fourth embodiment of the present invention. FIG. 19 is a cross-sectional view of another reactor. The second embodiment is different from the second embodiment in that two U-shaped iron cores are arranged so as to face each other to form leg portions having two gaps, and windings are wound around the respective leg portions. The winding method for one leg is the same as in the second embodiment.

18, the reactor 70 is arranged so that two U-shaped iron cores 51 and a U-shaped iron core 52 formed of a magnetic material face each other while ensuring

gaps

53a and 53b. A winding A1a and a winding A2a are wound around the first side leg 54a provided with the gap 53a. The first side leg 54a includes a pair of opposing leg portions 54ap and 54aq, and a gap 53a is formed between the leg portions 54ap and 54aq. A winding B1a and a winding B2a are wound around the second leg 54b provided with the gap 53b. The second leg 54b is composed of a pair of opposing leg portions 54bp and 54bq, and a gap 53b is formed between the leg portions 54bp and 54bq.

The winding A1a and the winding A2a are wound around the first side leg 54a along the extending direction of the first side leg 54a with the same number of turns C. For the winding A1a, a litz wire obtained by twisting many strands having a thin wire diameter is used, and for the winding A2a, a single wire having the same diameter as the finished diameter of the litz wire of the winding A1a is used. In the present embodiment, at least in a region surrounding the gap 53a, a litz wire (winding A1a) is disposed on the inner peripheral side close to the first side leg 54a, and a single wire (winding A2a) is disposed on the outer peripheral side. However, except for the region surrounding the gap, there is no such limitation, and the winding A1a and the winding A2a are arranged so as to be replaced in the middle along the extending direction of the first side leg 54a. The winding B1a and the winding B2a are also wound around the second side leg 54b, similarly to the winding A1a and the winding A2a.

As in the second embodiment, the litz wire (winding) is a single winding of the windings wound twice by applying the winding method to replace the single wire and the litz wire in this way. The average distance between the line A1a) and the center line 54ca of the first side leg 54a is the same as the single wire (winding A2a) that is the other single winding of the windings wound twice. It can be made substantially equal to the average distance between the center line 54ca of the first leg 54a. For this reason, the inductance of the winding A1a and the inductance of the winding A2a can be equalized, and the circulating current between the winding A1a and the winding A2a can be suppressed, thereby preventing an increase in copper loss. be able to. Here, the center line 54ca of the first side leg 54a corresponds to a line extending in the extending direction of the first side leg 54a by connecting the centers of the surfaces of the leg portion 54ap and the leg portion 54aq facing each other. Similarly, the winding B1a and the winding B2a are also wound by replacing the single wire and the litz wire. Further, in the

gaps

53a and 53b, as in the first embodiment, the windings A1a and B1a using the litz wires are arranged on the inner peripheral winding where the leakage magnetic flux is remarkably linked. Eddy current loss at the winding portion can also be reduced. Furthermore, since the number of parallel windings can be increased, the winding resistance can be further reduced.

In FIG. 18, the single wire and the litz wire are switched twice, but the litz wire (winding A1a) that is a single winding of the windings wound twice and the first side leg 54a. The average distance between the center line 54ca and the center line 54ca of the first side leg 54a is a single wire (winding A2a) that is one of the other windings of the multiple windings. If the winding A1a using the litz wire in the region surrounding the gap 53a is disposed on the inner peripheral side close to the first side leg 54a, the number of times the single wire and the litz wire are switched. The same effect can be obtained regardless of the place to be replaced. The same effect can be obtained for the winding B1a and the winding B2a by applying the same winding method.

In the description with reference to FIG. 18 described above, the entire winding is a double winding, but a multiple winding of triple or more may be used. FIG. 19 is a cross-sectional view of another reactor according to Embodiment 4 of the present invention. As shown in FIG. 19, the reactor 80 uses an arbitrary number of multiple turns n per side leg, and as shown in FIG. 16, the ends of the windings 1 to n are arranged in parallel in a winding direction that does not impair the inductance. You may connect. Even in this case, the average distance between the winding A1a, which is a single winding among the multiple windings, and the center line 54ca of the first side leg 54a is equal to each single winding other than the winding A1a. The minute windings (winding A2a (not shown) to winding Ana) are wound so as to be substantially equal to the respective average distances between the center line 54ca of the first side leg 54a. Further, in the region surrounding the gap 53a, a single wire is used so that the x-fold windings using the litz wire (winding A1a to winding Aja) are arranged on the inner peripheral side close to the first side leg 54a. The heavy windings (winding Aka to winding Ana) and the x-folding winding using the litz wire are replaced. The windings B1a to Bna are similarly configured. Thus, when the number of parallel turns is increased by adjusting the number of multiple turns x, the space for winding is maintained while maintaining the effect of reducing the eddy current loss due to the leakage magnetic flux from the gap 53a and the effect of suppressing the circulating current due to the difference in inductance. Effective use is possible, and winding resistance can be reduced.

In this embodiment, the windings are connected in parallel in the winding direction that does not impair the inductance, as shown in FIGS. 12 and 16, as in the third embodiment. Moreover, you may connect as shown in FIG. 13, FIG. 17, and may apply to a single phase power converter device.

Embodiment 5 FIG.
FIG. 20 is a cross-sectional view of the reactor in the fifth embodiment of the present invention. In the first to fourth embodiments, the case where one gap is provided for one leg of the iron core has been described as an example. However, as shown in FIG. 20, a plurality of legs are provided for one leg of the iron core. A gap may be provided. In FIG. 20, a reactor 90 is configured by combining

iron cores

91, 92, 93, 94, and 95 of a block-shaped magnetic material. In the case of FIG. 20, two

gaps

96 and 97 are formed.

As shown in FIG. 20, even when two or

more gaps

96 and 97 are formed, a large number of single wires (windings ka to na) and strands are twisted on the central leg 98 provided with the

gaps

96 and 97. A litz wire (windings 1a to ja) is wound in multiple layers. In the region surrounding the

gaps

96 and 97, the innermost circumference of the entire winding is composed of a litz wire, and the outermost circumference of the entire winding is composed of a single wire, thereby reducing eddy current loss of the winding portion in a high frequency region. In addition, it is possible to achieve both a reduction in winding resistance in a low frequency region and to realize a reactor with lower loss. Further, as shown in FIG. 20, the circulating current can be suppressed by applying a winding method that equalizes the inductances of the windings 1a to na.

In all the embodiments, the winding is illustrated as being directly applied to the iron core. However, the bobbin may be mounted on the iron core after the bobbin is wound. Moreover, in all the embodiments, it is not mentioned that the insulating paper is inserted between the windings. However, in order to ensure the insulation between the windings, the insulating paper is inserted between the windings. May be. However, when the windings are connected in parallel, the overlapping portions of the windings have substantially the same potential, and the winding can be applied on the windings without inserting insulating paper. FIG. 21 is a cross-sectional view showing an example of a winding arrangement. In this case, as shown in FIG. 21A, the second layer winding (WL2) is wound just above the first layer winding (WL1) wound on the first layer, and the second layer winding ( The third layer winding (WL3) may be wound just above WL2), but the second layer winding (WL2) is inserted in the gap between the first layer winding (WL1) as shown in FIG. ) And winding the third layer winding (WL3) in the gap between the second layer winding (WL2), the space factor of the conductor can be increased and the number of parallels can be increased. Can be further reduced.

1 to j, A1 to Aj, B1 to Bj, 1a to ja, A1a to Aja, B1a to Bja winding (Litz wire), 2, k to n, A2, Ak to An, B2, Bk to Bn, 2a, ka-na, A2a, Aka-Ana, B2a, Bka-Bna winding (single wire) 10, 20, 30, 40, 50, 60, 70, 80, 90, 103, 113 reactor, 11, 12

E-shaped core

51, 52 U-shaped iron core, 91, 92, 93, 94, 95 iron core, 13, 53a, 53b, 96, 97 gap, 14, 98 center leg, 14c, 54ca, 54cb center line, 14p, 14q, 54ap, 54 aq, 54 bp, 54 bq leg, 15 magnetic flux, 54 a first side leg, 54 b second side leg, 101, 111 three-phase power supply, 102, 112 capacitor, 104, 11 Power converter.

Claims

An iron core having at least one pair of legs facing each other, the gap being formed by the pair of legs;
A winding wound around the set of leg portions along the extending direction of the set of leg portions and wound in multiple layers so as to overlap in a direction substantially perpendicular to the extending direction;
In the region surrounding the gap, the innermost circumference of the winding is constituted by a litz wire in which a number of strands are twisted, and the outermost circumference of the winding is constituted by a single wire.
The reactor according to claim 1, wherein an outer diameter of the litz wire is substantially equal to an outer diameter of the single wire.
In the winding, the innermost circumference of the winding is constituted by the litz wire and the outermost circumference of the winding is constituted by the single wire in all regions surrounding the gap and the set of leg portions. The reactor of Claim 1 or 2 characterized by these.
In the partial area surrounding the pair of legs, the innermost circumference of the winding is constituted by the single wire, and the outermost circumference of the winding is constituted by the litz wire. The reactor according to claim 1 or 2.
A line obtained by extending the center of the surface facing the set of legs in the extending direction is a center line of the set of legs,
In the winding, the average distance between a single winding of the multiple windings and the center line is equal to the other single winding of the multiple windings. The reactor according to claim 1, wherein the reactor is configured to be substantially equal to an average distance between a winding of the coil and the center line.
The iron core has a plurality of opposing leg portions, and a plurality of gaps are formed by the plurality of leg portions,
The winding is wound around each of the plurality of sets of leg portions and connected in parallel in a winding direction in which the inductance of the winding does not disappear. The reactor according to item 1.
The iron core has a plurality of opposing leg portions, and a plurality of gaps are formed by the plurality of leg portions,
The windings are respectively wound around the plurality of sets of leg portions, and are parallel to each other in the winding direction in which the inductance of the winding does not disappear for each winding wound around the leg portions of the respective sets. The reactor according to any one of claims 1 to 5, wherein the reactor is connected.