JP4001505B2 - DC reactor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a DC reactor.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, some DC reactors provided in industrial electromagnetic equipment such as inverter circuits are configured to apply a bias magnetic field using a permanent magnet. An example of this type of DC reactor is disclosed in Japanese Patent Publication No. 46-37128 (hereinafter referred to as Prior Art 1).
[0003]
In the DC reactor of the prior art 1, a gap (hereinafter referred to as a magnetic gap) is provided between the I-shaped core and the E-shaped core, and a permanent magnet is inserted into the entire magnetic gap. Thus, a bias magnetic field is applied. In the DC reactor of prior art 1, since the coil magnetic flux generated by the coil wound around a part of the E-shaped layer core 10 penetrates the interior of the permanent magnet, the permanent magnet is reduced by the coil magnetic flux. There is a problem that it is easy to magnetize.
[0004]
In view of this, conventionally, there has been proposed a technique for preventing the demagnetization of the permanent magnet by preventing the coil magnetic flux generated by the coil from penetrating through the interior of the permanent magnet.
[0005]
FIG. 9 shows a DC reactor disclosed in Japanese Patent Application Laid-Open No. 8-31649 (hereinafter referred to as Conventional Technology 2) as an example. In the DC reactor of Prior Art 2, a C-shaped iron core 1 and a T-shaped iron core 2 are combined vertically to form a yoke, and a magnetic gap 3 is provided between the C-shaped iron core 1 and the T-shaped iron core 2. It is. In addition, the permanent magnet 4 extends vertically across the magnetic gap 3 and is disposed in close contact with the side surfaces of the C-shaped layer core 1 and the T-shaped layer core 2, and the back yoke 5 is further provided with the permanent magnet 4. It is laminated on the surface.
[0006]
According to the DC reactor of the prior art 2 configured as described above, the coil magnetic flux 7 generated by the coil 6 circulates inside the yoke without penetrating the permanent magnet 4 as a whole. Magnetism can be suppressed.
[0007]
[Problems to be solved by the invention]
However, in the DC reactor of the prior art 2, since the permanent magnet 4 is in close contact with the respective side surfaces of the C-shaped layer core 1 and the T-shaped layer core 2 so as to cover the magnetic gap 3, the number of permanent magnets 4 is reduced. It is not a preferable method for suppressing magnetism. That is, in a portion close to the magnetic gap 3 in the permanent magnet 4, as described in detail below, the decrease in the magnetic characteristics of the permanent magnet 4 due to the temperature rise and the leakage flux of the coil magnetic flux 7 from the magnetic gap 3 are in conflict. As a result, there is a risk of causing significant demagnetization.
[0008]
Here, the decrease in the magnetic characteristics of the permanent magnet 4 due to the temperature rise means that the demagnetization curve, which is a typical magnetic characteristic of the ferrite magnet material or rare earth magnet material constituting the permanent magnet 4, has a negative temperature coefficient. It means a phenomenon in which the magnetic properties decrease with increasing temperature. FIG. 10 exemplifies this phenomenon, and shows a temperature change of a demagnetization curve in NEOMAX (registered trademark) -37H manufactured by Sumitomo Special Metal Co., Ltd., which is an example of a rare earth magnet. Generally, in a permanent magnet having a large energy density and magnetic flux density such as NEOMAX (registered trademark) -37H, as the temperature rises, the holding force Hc and the residual magnetic flux density Br are remarkably reduced. 4 will be in the state which is easy to demagnetize.
[0009]
On the other hand, the leakage magnetic flux of the coil magnetic flux 7 from the magnetic gap 3 acts so that a part of the magnetic flux penetrates the proximity portion of the permanent magnet 4 with the magnetic gap 3 and demagnetizes the proximity portion. In addition, since the eddy current loss is caused in the portion of the permanent magnet 4 adjacent to the magnetic gap 3 and the temperature of the adjacent portion is increased, it becomes a major factor for demagnetizing the adjacent portion.
[0010]
As described above, in the DC reactor according to the related art 2, when the proximity portion of the permanent magnet 4 to the magnetic gap 3 is likely to be demagnetized by the temperature rise, the proximity portion is a leakage flux of the coil magnetic flux 7. This causes the problem of demagnetization.
[0011]
This invention is made | formed in view of the said situation, and it aims at obtaining the direct current | flow reactor which can suppress the demagnetization of the permanent magnet by the leakage flux of a coil magnetic flux.
[0012]
[Means for Solving the Problems]
  To achieve the above object, a DC reactor according to the present invention includes a closed magnetic circuit type main yoke that forms a closed magnetic circuit through a main magnetic gap that is a magnetic gap, and a coil that generates magnetic flux in the closed magnetic circuit And a permanent magnet that applies a bias magnetic field to the magnetic flux generated by the coil, the permanent magnet is disposed in a manner that straddles the main magnetic gap and is separated from the main yoke. And the main magnetic gapAuxiliary yokes are projected from the side surfaces of the main yokes at positions separated from each other in opposite directions,ThroughSaidConnect the permanent magnet to the main yokeA gap of at least half of the main magnetic gap distance is secured between the main yoke and the permanent magnet.It is characterized by that.
[0013]
  According to the present invention, the permanent magnet is disposed in a manner that straddles the main magnetic gap and is separated from the main yoke.A gap of at least half the main magnetic gap distance is secured between the main yoke and the permanent magnet.Therefore, the amount of the leakage flux of the coil magnetic flux leaking from the main magnetic gap and passing through the permanent magnet is reduced, and the temperature rise of the permanent magnet due to the eddy current loss accompanying the leakage magnetic flux is suppressed.
[0014]
  In the DC reactor according to the next invention, in the above invention,Opposition of the auxiliary yoke connected to the magnetic pole faces at both ends of the permanent magnetThe area is smaller than the opposing area of the main magnetic gap.
[0015]
  According to this invention,Opposition of the auxiliary yoke connected to the magnetic pole faces at both ends of the permanent magnetSince the area is smaller than the opposing area of the main magnetic gap, the magnetic resistance of the magnetic path leading to the permanent magnet is larger than the magnetic resistance of the magnetic path leading to the main magnetic gap.
[0016]
  In the DC reactor according to the next invention, in the above invention,The difference between the inner and outer circumferences of the magnetic path length inside the main yoke is different.The main magnetic gap is formed near the corner portion.,in frontThe permanent magnetIn the vicinity of the main magnetic gap, the outer circumference side of the main yoke where the magnetic path length becomes longerIt is characterized by having been arranged in.
[0017]
According to the present invention, since the magnetic path leading to the permanent magnet is larger than the magnetic path leading to the main magnetic gap, the magnetic resistance in the magnetic path leading to the permanent magnet is the magnetic resistance in the magnetic path leading to the main magnetic gap. It becomes larger than the resistance.
[0022]
  The DC reactor according to the next invention is the above-described invention, wherein the gap between the main yoke and the permanent magnet isIncrease or decreaseLetThe aboveConnection area between auxiliary yoke and permanent magnetBy increasing or decreasingThe permanent magnetIncrease or decrease the bias magnetic flux created byIt is characterized by that.
[0023]
  According to this invention, the gap between the main yoke and the permanent magnet is increased.The bias magnetic flux generated by the permanent magnet is increased / decreased by increasing / decreasing the connecting area between the auxiliary yoke and the permanent magnet.
[0024]
The direct current reactor according to the next invention is characterized in that, in the above invention, the main iron is constituted by a laminated iron core, a combination of one or more iron cores using a soft magnetic ferrite bulk iron core, or a continuous molded body. .
[0025]
According to this invention, the primary iron is constituted by a combination of one or more iron cores using a laminated iron core or a soft magnetic ferrite bulk iron core, or a continuous molded body.
[0026]
DETAILED DESCRIPTION OF THE INVENTION
Exemplary embodiments of a DC reactor according to the present invention will be explained below in detail with reference to the accompanying drawings.
[0027]
Embodiment 1 FIG.
1A and 1B show a DC reactor according to the first embodiment. FIG. 1A is a plan view and FIG. 1B is a sectional side view. This DC reactor is provided, for example, in an inverter circuit, and suppresses pulsation of DC current in the inverter circuit.
[0028]
The DC reactor shown in FIG. 1 is a main iron by combining an E-shaped layer core 10 and an I-shaped layer core 11 laminated with soft magnetic thin plates vertically.
[0029]
The E-shaped forming layer core 10 has a structure in which one end of a substantially rectangular parallelepiped central leg 10C, right leg 10R, and left leg 10L that are connected in parallel is orthogonally connected to the center of the rectangular parallelepiped portion and the left and right ends, respectively. Have. On the other hand, the I-shaped layer core 11 has a substantially rectangular parallelepiped shape.
[0030]
Here, since the right leg 10R and the left leg 10L in the E-shaped core iron core 10 are formed shorter than the central leg 10C, the bottom surface of the central leg 10C of the E-shaped core iron core 10 is the I-shaped core iron core 11. If connected, main magnetic gaps G are formed between the right leg 10R and the I-shaped core iron core 11 and between the left leg 10L and the I-shaped core iron core 11, respectively. Thus, this DC reactor constitutes a substantially Japanese-shaped three-legged iron core including the main magnetic gap G provided on the left and right sides of the main yoke in the magnetic circuit.
[0031]
When assembling the main yoke, a nonmagnetic insulating plate is inserted between the mating surfaces of the main magnetic gap G, specifically, the surfaces constituting the main magnetic gap G so as to face each other. G may be held. Further, an anti-vibration material may be inserted between the mating surfaces of the central leg 10C of the E-shaped layer core 10 and the I-shaped layer core 11 to suppress electromagnetic vibration between them.
[0032]
Further, in the DC reactor of FIG. 1, a coil 12 is wound around a central leg 10 </ b> C of the E-shaped layer core 10, while a protruding auxiliary yoke 13 is provided on the E-shaped layer core 10 and the I-shaped layer core 11. , 14 (auxiliary yoke) are provided.
[0033]
The coil 12 generates a coil magnetic flux Φc when a current is passed through the coil 12. The coil 12 is configured such that a current flows in the coil 12 so that the coil magnetic flux Φc in the main yoke opposes a bias magnetic flux Φm by a permanent magnet 15 described later.
[0034]
The protruding auxiliary yokes 13 and 14 are provided on the side surfaces of the right leg 10R and the left leg 10L of the E-shaped layer core 10 constituting the main yoke with the main magnetic gap G interposed between the upper and lower sides, and the I-shaped layer core 11. It is the part which protruded from the side. The protruding auxiliary yokes 13 and 14 can be configured by stacking, for example, soft magnetic thin plates punched integrally with the main yoke. Here, the opposing area As of the protruding auxiliary yokes 13 and 14 facing each other is determined by the right leg 10R and the left leg 10L of the E-shaped layer core 10 constituting the main magnetic gap G and the I-shaped layer core 11. It is configured to be smaller than the facing area Ag.
[0035]
A permanent magnet 15 is disposed between the protruding auxiliary yokes 13 and 14 so as to straddle the main magnetic gap G. The permanent magnet 15 biases the coil magnetic flux Φc generated by the coil 12 and is configured in a flat plate shape. The permanent magnet 15 is inserted between the protruding auxiliary yokes 13 and 14 from the side, and is magnetized in antiparallel to the traveling direction of the coil magnetic flux Φc passing through the main magnetic gap G. In this state, they are connected to the protruding auxiliary yokes 13 and 14, respectively.
[0036]
Here, the permanent magnet 15 is magnetized so that both end faces in the longitudinal direction in the longitudinal section become magnetic pole faces, and when inserted between the protruding auxiliary yokes 13 and 14, The magnetic pole surface is configured to be a contact surface with the protruding auxiliary yokes 13 and 14. In this permanent magnet 15, the length in the longitudinal direction in the longitudinal section is the length Hm in the magnetization direction, and the ratio of the magnetic pole cross-sectional area to the length Hm in the magnetization direction is made small. However, the magnetic pole cross-sectional area of the permanent magnet 15 is set larger than the cross-sectional area assumed to be necessary from the amount of generation of a desired bias magnetic field. When the permanent magnet 15 is inserted between the protruding auxiliary yokes 13, 14, the center line of the main magnetic gap G and the magnetic pole neutral line Cm of the permanent magnet 15, that is, the position where the magnetic pole is inverted coincides. I have to do it.
[0037]
A gap adjusting spacer 16 having a thickness Ls is inserted between the permanent magnet 15 and the main yoke, that is, the E-shaped layer core 10 and the I-shaped layer core 11.
[0038]
The gap adjusting spacer 16 is formed of an insulating plate that is nonmagnetic and has a lower thermal conductivity than iron, and defines a gap between the permanent magnet 15 and the E-shaped layer core 10 and I-shaped layer core 11. To do.
[0039]
Thereby, in the direct current reactor of the first embodiment, the permanent magnet 15 and the E-shaped layer core 10 and the I-shaped layer core 11 are not in close contact with each other, and a magnetic gap (with a separation distance Ls between them) ( Hereinafter, the magnetic gap Gs) is secured. Here, the separation distance Ls of the magnetic gap Gs is preferably set to ½ or more with respect to the separation distance Lg of the main magnetic gap G. That is, if the separation distance Ls of the magnetic gap Gs is smaller than that, it is not preferable because the amount of leakage magnetic flux of the coil magnetic flux Φc described later penetrates the permanent magnet 15 locally increases.
[0040]
In the first embodiment configured as described above, when the coil 12 is excited by a pulsating direct current, as illustrated by a solid line in FIG. 1B, the coil magnetic flux Φc generated by the coil 12 is formed in an E shape. Branching left and right from the central leg 10C of the layered iron core 10, flows through the right leg 10R and the left leg 10L, passes through the main magnetic gap G, passes through the I-shaped layered core 10 and then passes through the I-shaped layered core 10 Return to 10 central legs 10C. On the other hand, the bias magnetic flux Φm produced by the permanent magnet 15 is applied to the right leg 10R and the left leg 10L of the E-shaped layered iron core 10 via the protruding auxiliary yoke 13 as shown by the broken line in FIG. After flowing in, it returns to the permanent magnet 15 through the central leg 10C of the E-shaped layer core 10, the I-shaped layer core 11 and the protruding auxiliary yoke 14.
[0041]
Here, in the first embodiment, the separation distance Lg of the main magnetic gap G <the length Hm in the magnetization direction of the permanent magnet, and the facing area Ag in the main magnetic gap> the protruding auxiliary yokes 13 and 14. It is comprised so that it may become opposing area As. Therefore, in the parallel magnetic path of the magnetic path on the E-shaped layer core 10 and the I-shaped layer core 11 side and the magnetic path on the protruding auxiliary yokes 13 and 14 side, the magnetic field on the protruding auxiliary yokes 13 and 14 side. Since the path has a larger magnetic resistance than the magnetic path on the E-shaped layer core 10 and I-shaped layer core 11 side, it is possible to prevent the coil magnetic flux Φc from bypassing and flowing into the permanent magnet 15. . Moreover, since the projecting auxiliary yokes 13 and 14 are respectively provided at the corner portions at the left and right ends of the I-shaped layer core 11 in which the coil magnetic flux Φc bends at right angles, that is, at the outer circumferential side of the magnetic path. The effect of suppressing the coil magnetic flux Φc from passing through the protruding auxiliary yokes 13 and 14 due to the difference in magnetic resistance due to the difference between the inner and outer circumferences of the magnetic path length is high.
[0042]
As a result, in the central leg 10C of the E-shaped core 10 around which the coil 12 is wound, the coil magnetic flux Φc by the coil 12 and the bias magnetic flux Φm by the permanent magnet 15 flow in opposition, whereas the main magnetic gap The coil magnetic flux Φc and the bias magnetic flux Φm are surely branched at the upper and lower portions across G. Therefore, in the central leg 10C of the E-shaped core iron core 10, the coil magnetic flux Φc by the coil 12 is biased in the reverse direction by the bias magnetic flux Φm by the permanent magnet 15, and the upper and lower sides sandwich the main magnetic gap G. In this portion, the demagnetization effect on the permanent magnet 15 such that the coil magnetic flux Φc passes through the permanent magnet 15 via the protruding auxiliary yokes 13 and 14 can be suppressed.
[0043]
On the other hand, since the magnetic gap Gs is provided between the permanent magnet 15 and the main yoke, that is, the E-shaped layer core 10 and the I-shaped layer core 11, the leakage flux of the coil magnetic flux Φc from the main magnetic gap G. Can pass through the portion of the permanent magnet 15 adjacent to the main magnetic gap G.
[0044]
FIG. 2 exemplifies the result of magnetic field analysis to support this, FIG. 2 (a) shows a model to be subjected to magnetic field analysis, and FIG. 2 (b) shows the analysis result by calculation. In this magnetic field analysis, a non-linear static magnetic field analysis is performed in a ¼ region, taking into account the symmetry of the iron core structure, with a model of a substantially sun-shaped three-legged iron core that does not have the permanent magnet 15. In this analysis, the number of turns of the coil is 9 turns, taking into account the excitation rush current, the energizing current is 420A, which is three times the rated value, the separation distance Lg of the main magnetic gap G is 1.25 mm, and the main yoke is a non-directional electromagnetic It is set as what is comprised with the laminated iron core of steel plate 50A470. Further, in FIG. 2A, the dimensions L1, L2, L3, and L4 of the main yoke are 45 mm, 60 mm, 48 mm, and 11 mm, respectively, and the coil from the main magnetic gap G in the space of the square mesh surrounded by the circles. The leakage magnetic flux density of the magnetic flux is calculated.
[0045]
In FIG. 2B, the horizontal axis of the graph is the distance in the Z direction from the magnetic pole neutral line Cm of the magnet (the magnetic pole neutral line Cm coincides with the center line of the main magnetic gap as described above). Is plotted with the leakage flux density Bx of the X direction component and the leakage flux density Bz of the Z direction component. Here, the leakage magnetic flux density Bx and the leakage magnetic flux density Bz are calculated for three cases of 50 μm, 0.5 mm, and 1 mm using the X-direction distance Lx indicating the distance away from the side surface of the main yoke as a parameter. The results are plotted.
[0046]
From the analysis result shown in FIG. 2B, when the X-direction distance Lx from the side surface of the main yoke is 50 μm, the leakage magnetic flux density Bx and the leakage magnetic flux density Bz in the vicinity of the main magnetic gap G are both large, The value is around 0.7T. On the other hand, when the X-direction distance Lx is 0.5 mm which is a ½ mm or less of the separation distance Lg of the main magnetic gap G, that is, 1.25 mm, the leakage magnetic flux density Bx and leakage in the vicinity of the main magnetic gap The magnetic flux density Bz is reduced to 2/3 or less of the previous value. That is, the leakage magnetic flux from the main magnetic gap G is remarkably reduced by increasing the X-direction distance Lx from the side surface of the main yoke.
[0047]
As a result, in the DC reactor according to the first embodiment, the magnetic gap Gs is provided, and preferably, the separation distance Ls of the magnetic gap Gs is set to be 1/2 or more of the separation distance Lg of the main magnetic gap G. As a result, the leakage flux of the coil flux Φc passing through the portion of the permanent magnet 15 that is close to the main magnetic gap G is significantly reduced. Moreover, the eddy current loss due to the leakage flux of the coil magnetic flux Φc is remarkably reduced in the vicinity of the main magnetic gap G in the permanent magnet 15, and the main magnetic gap G in the permanent magnet 15 is reduced along with the eddy current loss. It is possible to prevent the temperature of the adjacent portion from being raised.
[0048]
Therefore, according to the direct current reactor of the first embodiment, the temperature rise of the permanent magnet 15 in the vicinity of the main magnetic gap G can be suppressed, and the amount of leakage flux of the coil flux Φc passing through the proximity is reduced. Therefore, the demagnetization of the portion near the main magnetic gap G in the permanent magnet 15 can be suppressed. Thereby, according to this Embodiment 1, the demagnetization of the permanent magnet 15 by the leakage magnetic flux of coil magnetic flux (PHI) c can be suppressed.
[0049]
On the other hand, the space between the side surface of the permanent magnet 15 and the side surfaces of the main iron, that is, the E-shaped layer core 10 and the I-shaped layer core 11 is composed of a nonmagnetic insulating plate having a thermal conductivity smaller than that of iron. The gap adjusting spacer 16 or the air layer is filled. As a result, the heat generated in the E-shaped core iron core 10 and the I-shaped core iron core 11 caused by iron loss and the like, and the heat generated in the coil 12 caused by copper loss and the like are mainly matched with the protruding auxiliary yokes 13 and 14. Heat is transferred through the surface, that is, the contact surface. Here, in the DC reactor according to the first embodiment, the permanent magnet 15 magnetized so that both end faces in the longitudinal direction in the longitudinal section become magnetic pole faces is inserted between the protruding auxiliary yokes 13 and 14. The magnetic pole surface is configured to be a butting surface with the protruding auxiliary yokes 13 and 14.
[0050]
Therefore, according to the direct current reactor of the first embodiment, the area of the contact surface can be designed smaller than the case where the side surface of the permanent magnet 15 is used as the contact surface, and heat conduction through the contact surface can be suppressed. For this reason, it becomes possible to suppress the situation where the performance of the permanent magnet 15 deteriorates as the temperature rises. As a result, the LI characteristic of the DC reactor can be maintained as desired as possible. .
[0051]
Furthermore, according to the direct current reactor of the first embodiment, since the ratio of the magnetic pole cross-sectional area to the length Hm in the magnetization direction of the permanent magnet 15 is reduced, the operating point of the permanent magnet 15 is set high. More stable magnet characteristics can be secured against demagnetization factors such as an external magnetic field and a temperature rise of the permanent magnet 15.
[0052]
Furthermore, according to the DC reactor of the first embodiment, the demagnetization performance with respect to the permanent magnet 15 is improved by the above-described configuration, so that it is possible to use an inexpensive permanent magnet material having a small coercive force. As a result, the manufacturing cost of the DC reactor can be reduced.
[0053]
On the other hand, in the DC reactor of the first embodiment, the permanent magnet 15 is inserted between the protruding auxiliary yokes 13 and 14 from the side, and the magnetic pole cross-sectional area of the permanent magnet 15 is set to a desired value. It is larger than the cross-sectional area assumed to be necessary from the amount of generation of the bias magnetic field.
[0054]
As a result, the abutting area Am of the permanent magnet 15 and the protruding auxiliary yokes 13, 14, that is, the connection area can be increased or decreased, and the bias magnetic flux Φm can be increased or decreased at any time regardless of the coil magnetic flux Φc. Therefore, as illustrated in FIG. 3, the operating range of the inductance L of the DC reactor with respect to the exciting current I can be adjusted at any time. For example, when the magnetic gap length Ls is in a relationship of LsB <LsA <LsC, if the magnetic gap length Ls is reduced by changing from LsA to LsB, the LI characteristic is on the high current side, that is, on the horizontal axis. If the magnetic gap length Ls is increased by shifting from the positive direction side to LsA to LsC, the LI characteristics shift to the low current side.
[0055]
Therefore, according to the direct current reactor of the first embodiment, even after the direct current reactor is assembled by changing the abutting area Am between the permanent magnet 15 and the protruding auxiliary yokes 13 and 14, the work error It is possible to obtain a desired LI characteristic by correcting a deviation from the design bias magnetic flux caused by variations in material characteristics. Note that if the magnetic gap length Ls is too narrow, the inductance value at a low current may be reduced, so that it is necessary to make a change within an allowable range.
[0056]
Embodiment 2. FIG.
FIG. 4 is a cross-sectional side view showing a DC reactor according to the second embodiment. In the second embodiment, the C-shaped core iron core 20 and the T-shaped core iron core 21 are combined in the upper and lower directions to form a main yoke, and, as in the first embodiment described above, a substantially sun-shaped three-leg iron core type DC. It constitutes a reactor.
[0057]
The C-shaped layered iron core 20 has a structure in which one ends of a substantially rectangular parallelepiped right leg 20R and a left leg 20L which are in a parallel relationship are orthogonally connected to left and right ends of the rectangular parallelepiped portion. On the other hand, the T-shaped layered iron core 21 has a structure in which a rectangular parallelepiped leg portion 21C is orthogonally connected to the center of the rectangular parallelepiped portion and integrated.
[0058]
In the DC reactor according to the second embodiment, the coil 22 is wound around the leg portion 21 </ b> C of the T-shaped layer core 21, while the main magnetic gap is between the C-shaped layer core 20 and the T-shaped layer core 21. G is provided. Further, in the DC reactor according to the second embodiment, the protruding auxiliary yokes 23 and 24 are provided at portions located above and below the main magnetic gap G in the C-shaped layer core 20 and the T-shaped layer core 21. The permanent magnet 15 is inserted and connected between the protruding auxiliary yokes 23 and 24. Except for these, in the DC reactor of the second embodiment, the assembly configuration and operation are the same as those of the first embodiment described above, so the same reference numerals are given and detailed description is omitted.
[0059]
According to the direct current reactor of the second embodiment, similarly to the first embodiment, the magnetic gap Gs is provided between the permanent magnet 15 and the main yoke, and the separation distance Ls of the magnetic gap Gs is set to the main magnetism. It is set to be 1/2 or more of the separation distance Lg of the gap G. Therefore, the temperature rise due to the eddy current loss in the portion near the main magnetic gap G in the permanent magnet 15 can be suppressed, and the amount of leakage flux of the coil magnetic flux Φc passing through the portion near the main magnetic gap G in the permanent magnet 15. Can be reduced. As a result, it is possible to suppress demagnetization of the portion of the permanent magnet 15 that is close to the main magnetic gap G. Therefore, according to the second embodiment, the permanent magnet 15 is demagnetized by the leakage flux of the coil flux Φc. Can be suppressed.
[0060]
In addition, it is possible to prevent the coil magnetic flux Φc from passing through the permanent magnet 15 via the auxiliary yoke, to maintain the LI characteristic of the DC reactor as desired as much as possible, and to be more stable against demagnetization factors. It is possible to obtain a desired LI characteristic by ensuring a proper magnet characteristic, making it possible to use a cheaper permanent magnet material, or correcting a deviation with respect to a design bias magnetic flux. Same as 1.
[0061]
Embodiment 3 FIG.
FIG. 5 is a cross-sectional side view showing a DC reactor according to the third embodiment. In the third embodiment, the C-shaped layered core 30 and the I-shaped layered core 31 are combined in the vertical direction to form a main yoke, thereby forming a substantially square-shaped two-legged core type DC reactor.
[0062]
The C-shaped forming layer core 30 has a structure in which one end of a substantially rectangular parallelepiped right leg 30R and left leg 30L that are in parallel relation is orthogonally connected to both left and right ends of the rectangular parallelepiped portion. The I-shaped layer core 31 has a rectangular parallelepiped shape.
[0063]
In the DC reactor of the third embodiment, the coil 32 is wound around the I-shaped layer core 31, while the main magnetic gap G is provided between the C-shaped layer core 30 and the I-shaped layer core 31. It is. Further, in the DC reactor according to the third embodiment, the protruding auxiliary yokes 33 and 34 are provided at portions located above and below the main magnetic gap G in the C-shaped layer core 30 and the I-shaped layer core 31. A permanent magnet 15 is inserted and connected between the protruding auxiliary yokes 33 and 34. Except for these, in the DC reactor of the third embodiment, the assembly configuration and operation are the same as those of the first embodiment described above, and therefore the same reference numerals are given and detailed description thereof is omitted.
[0064]
According to the direct current reactor of the third embodiment, similarly to the first embodiment, the magnetic gap Gs is provided between the permanent magnet 15 and the main yoke, and the separation distance Ls of the magnetic gap Gs is set to the main magnetism. It is set to be 1/2 or more of the separation distance Lg of the gap G. Therefore, the temperature rise due to the eddy current loss in the portion near the main magnetic gap G in the permanent magnet 15 can be suppressed, and the amount of leakage flux of the coil magnetic flux Φc passing through the portion near the main magnetic gap G in the permanent magnet 15. Can be reduced. As a result, it is possible to suppress the demagnetization of the portion of the permanent magnet 15 close to the main magnetic gap G. Therefore, according to the third embodiment, the demagnetization of the permanent magnet 15 due to the leakage flux of the coil flux Φc is prevented. Can be suppressed.
[0065]
In addition, it is possible to prevent the coil magnetic flux Φc from passing through the permanent magnet 15 via the auxiliary yoke, to maintain the LI characteristic of the DC reactor as desired as much as possible, and to be more stable against demagnetization factors. It is possible to obtain a desired LI characteristic by ensuring a proper magnet characteristic, making it possible to use a cheaper permanent magnet material, or correcting a deviation with respect to a design bias magnetic flux. Same as 1.
[0066]
In addition to the effects described above, according to the third embodiment, since the mating surface of the main magnetic gap G and the mating surface of the main yoke at the time of assembly can be used together, the mating surface is reduced, Manufacturing costs can be reduced by eliminating the need for a vibration isolator inserted between the mating surfaces of the main yokes.
[0067]
Embodiment 4 FIG.
FIG. 6 is a cross-sectional side view showing a DC reactor according to the fourth embodiment. In the fourth embodiment, the C-shaped layered iron cores 40 and 41 are combined to the left and right to serve as a main yoke, and a substantially square-shaped two-leg iron core type DC reactor is configured.
[0068]
The C-shaped layered cores 40 and 41 are formed by orthogonally connecting one ends of the substantially rectangular parallelepiped right legs 40R and 41R and the left legs 40L and 41L in parallel to the left and right ends (upper and lower in FIG. 6) of the rectangular parallelepiped portion. Have an integrated structure.
[0069]
In the DC reactor of the fourth embodiment, the coils 42 are wound around the C-shaped cores 40 and 41, respectively, while the main magnetic gap G is provided between the C-shaped cores 40 and 41. It is. Further, in the DC reactor according to the fourth embodiment, the protruding auxiliary yokes 43 and 44 are provided at portions located above and below the main magnetic gap G in the C-shaped formation cores 40 and 41, and these protruding shapes A permanent magnet 15 is inserted and connected between the auxiliary yokes 43 and 44. Except for these, in the DC reactor of the fourth embodiment, the assembly configuration and operation are the same as those of the first embodiment described above, and therefore, the same reference numerals are given and detailed description thereof is omitted.
[0070]
According to the direct current reactor of the fourth embodiment, similarly to the first embodiment, the magnetic gap Gs is provided between the permanent magnet 15 and the main yoke, and the separation distance Ls of the magnetic gap Gs is set to the main magnetism. It is set to be 1/2 or more of the separation distance Lg of the gap G. Therefore, the temperature rise due to the eddy current loss in the portion near the main magnetic gap G in the permanent magnet 15 can be suppressed, and the amount of leakage flux of the coil magnetic flux Φc passing through the portion near the main magnetic gap G in the permanent magnet 15. Can be reduced. As a result, it is possible to suppress the demagnetization of the portion of the permanent magnet 15 close to the main magnetic gap G. Therefore, according to the fourth embodiment, the demagnetization of the permanent magnet 15 due to the leakage flux of the coil flux Φc is prevented. Can be suppressed.
[0071]
In addition, it is possible to prevent the coil magnetic flux Φc from passing through the permanent magnet 15 via the auxiliary yoke, to maintain the LI characteristic of the DC reactor as desired as much as possible, and to be more stable against demagnetization factors. It is possible to obtain a desired LI characteristic by ensuring a proper magnet characteristic, making it possible to use a cheaper permanent magnet material, or correcting a deviation with respect to a design bias magnetic flux. Same as 1.
[0072]
In addition to the effects described above, according to the fourth embodiment, as in the third embodiment, the mating surface of the main magnetic gap G and the mating surface of the main yoke during assembly can be used together. In addition to reducing the mating surfaces, it is possible to reduce the manufacturing cost by eliminating the need for vibration-proofing materials inserted between the mating surfaces of the main yoke.
[0073]
Embodiment 5 FIG.
FIG. 7 is a cross-sectional side view showing a DC reactor according to the fifth embodiment. In the fifth embodiment, the E-shaped formation cores 50 and 51 are combined in the upper and lower directions to form a main yoke, thereby forming a substantially day-shaped three-legged core type DC reactor.
[0074]
The E-shaped formation cores 50 and 51 have substantially rectangular parallelepiped center legs 50C and 51C, right legs 50R and 51R, and left legs 50L and 51L, which are parallel to each other, perpendicular to the center of the rectangular parallelepiped portion and the left and right ends, respectively Connected and integrated structure.
[0075]
In the DC reactor according to the fifth embodiment, the coils 52 are wound around the center legs 50C and 51C of the E-shaped layer cores 50 and 51, respectively. A magnetic gap G is provided. Further, in the direct current reactor of the fifth embodiment, the protruding auxiliary yokes 53 and 54 are provided in portions located above and below the main magnetic gap G in the E-shaped formation cores 50 and 51, and these protruding shapes A permanent magnet 15 is inserted and connected between the auxiliary yokes 53 and 54. Except for these, in the DC reactor of the fifth embodiment, the assembly configuration and operation are the same as those of the first embodiment described above, and therefore, the same reference numerals are given and detailed description thereof is omitted.
[0076]
According to the DC reactor of the fifth embodiment, similarly to the first embodiment, the magnetic gap Gs is provided between the permanent magnet 15 and the main yoke, and the separation distance Ls of the magnetic gap Gs is set to the main magnetism. It is set to be 1/2 or more of the separation distance Lg of the gap G. Therefore, the temperature rise due to the eddy current loss in the portion near the main magnetic gap G in the permanent magnet 15 can be suppressed, and the amount of leakage flux of the coil magnetic flux Φc passing through the portion near the main magnetic gap G in the permanent magnet 15. Can be reduced. As a result, it is possible to suppress the demagnetization of the portion of the permanent magnet 15 that is close to the main magnetic gap G. Therefore, according to the fifth embodiment, the permanent magnet 15 is demagnetized by the leakage flux of the coil flux Φc. Can be suppressed.
[0077]
In addition, it is possible to prevent the coil magnetic flux Φc from passing through the permanent magnet 15 via the auxiliary yoke, to maintain the LI characteristic of the DC reactor as desired as much as possible, and to be more stable against demagnetization factors. It is possible to obtain a desired LI characteristic by ensuring a proper magnet characteristic, making it possible to use a cheaper permanent magnet material, or correcting a deviation with respect to a design bias magnetic flux. Same as 1.
[0078]
In the above-described first to fifth embodiments, the example in which the main yoke including the protruding auxiliary yoke is configured by the stratified core is shown. However, even if the bulk iron core is formed by the soft magnetic ferrite having a high specific resistance. Of course, the same effect can be obtained.
[0079]
Embodiment 6 FIG.
FIG. 8 shows a DC reactor according to the sixth embodiment. FIG. 8 (a) is a developed plan view of the main yoke, and FIG. 8 (b) is a sectional side view. In the sixth embodiment, one H-shaped layered iron core 60 is used as a main yoke, and a substantially sun-shaped three-leg iron core type DC reactor is configured.
[0080]
In FIG. 8A, the H-shaped layered iron core 60 has an upper arm portion 60A and a bottom arm portion 60B that are positioned above and below the central leg 60C, and further, the upper arm portion 60A and the bottom arm portion 60B. End portions 60a and 60b are provided at the left and right ends via thin-walled connecting portions 60a 'and 60b', respectively. The H-shaped layered iron core 60 is manufactured as an integral structure.
[0081]
Protruding auxiliary yokes 63 and 64 are provided at the tip portions 60a and 60b, respectively, so as to be in a positional relationship facing each other when the main yoke is assembled. The tip portions 60a and 60b are portions constituting the right leg 60R and the left leg 60L of the H-shaped forming layer core 60 when the main yoke is assembled.
[0082]
In the DC reactor according to the sixth embodiment, after the coil 62 is wound around the central leg 60C of the H-shaped layer core 60, the thin joint portions 60a 'and 60b' are bent inward to form the joint butting surface Ac. The main magnetic gap G is formed by closing so as to overlap, and after the main magnetic gap G is held by the nonmagnetic insulating plate, the permanent magnet 15 is inserted and connected between the protruding auxiliary yokes 63 and 64. After that, a substantially sun-shaped three-leg iron core type DC reactor is formed.
[0083]
In the sixth embodiment, except for the main assembly configuration described above, the operation is the same as that of the fifth embodiment described above, and thus the same reference numerals are given and detailed description thereof is omitted.
[0084]
According to the direct current reactor of the sixth embodiment, similarly to the first embodiment, the magnetic gap Gs is provided between the permanent magnet 15 and the main yoke, and the separation distance Ls of the magnetic gap Gs is set to the main magnetism. It is set to be 1/2 or more of the separation distance Lg of the gap G. Therefore, the temperature rise due to the eddy current loss in the portion near the main magnetic gap G in the permanent magnet 15 can be suppressed, and the amount of leakage flux of the coil magnetic flux Φc passing through the portion near the main magnetic gap G in the permanent magnet 15. Can be reduced. As a result, it is possible to suppress demagnetization of the portion of the permanent magnet 15 that is close to the main magnetic gap G. Therefore, according to the sixth embodiment, the permanent magnet 15 is demagnetized by the leakage flux of the coil flux Φc. Can be suppressed.
[0085]
In addition, it is possible to prevent the coil magnetic flux Φc from passing through the permanent magnet 15 via the auxiliary yoke, to maintain the LI characteristic of the DC reactor as desired as much as possible, and to be more stable against demagnetization factors. It is possible to obtain a desired LI characteristic by ensuring a proper magnet characteristic, making it possible to use a cheaper permanent magnet material, or correcting a deviation with respect to a design bias magnetic flux. Same as 1.
[0086]
In addition to the effects described above, according to the direct current reactor of the sixth embodiment, it is not necessary to provide a butt surface on the center leg 60C of the H-shaped layer core 60 around which the coil 62 is wound. As a result, there is no work gap that occurs, so that the decrease in inductance L of the DC reactor, electromagnetic vibration, and the like due to the work gap can be suppressed.
[0087]
Furthermore, according to the DC reactor of the sixth embodiment, the main yoke is an integral structure through the thin-walled connecting portions 60a ′ and 60b ′, so that the electromagnetic vibration through the joint butting surface Ac is suppressed. can do.
[0088]
【The invention's effect】
  As described above, according to the present invention, the permanent magnet is disposed in a manner that straddles the main magnetic gap and is separated from the main yoke.A gap of at least half of the main magnetic gap distance is secured between the main yoke and the permanent magnet.Therefore, the amount of leakage flux of the coil magnetic flux leaking from the main magnetic gap and passing through the permanent magnet is reduced, and the temperature rise of the permanent magnet due to eddy current loss accompanying the leakage magnetic flux is suppressed. The demagnetization of the permanent magnet due to the leakage flux of the coil magnetic flux can be suppressed.
[0089]
  According to the following invention,Opposition of the auxiliary yoke connected to the magnetic pole faces at both ends of the permanent magnetSince the area is smaller than the opposing area of the main magnetic gap, the reluctance of the magnetic path leading to the permanent magnet is larger than the reluctance of the magnetic path leading to the main magnetic gap. It is possible to prevent the coil magnetic flux from passing through the permanent magnet through the connection surface with the permanent magnet.
[0090]
According to the next invention, since the magnetic path leading to the permanent magnet is larger than the magnetic path leading to the main magnetic gap, the magnetic resistance in the magnetic path leading to the permanent magnet is in the magnetic path leading to the main magnetic gap. It becomes larger than the magnetic resistance. Therefore, it is possible to more reliably suppress the coil magnetic flux from passing through the permanent magnet through the connection surface between the main yoke and the permanent magnet.
[0093]
  According to the next invention, the gap between the main yoke and the permanent magnet isIncrease or decrease the bias magnetic flux generated by the permanent magnet by increasing or decreasing the connection area between the auxiliary yoke and the permanent magnet.Therefore, it is easy to obtain a desired LI characteristic by correcting a deviation with respect to the design bias magnetic flux caused by a work error, variation in material characteristics, and the like.
[0094]
According to the next invention, the main iron is constituted by a laminated iron core, a combination of one or more iron cores using a soft magnetic ferrite bulk iron core, or a continuous molded body.
[Brief description of the drawings]
1A and 1B show a DC reactor according to Embodiment 1 of the present invention, in which FIG. 1A is a plan view and FIG. 1B is a sectional side view.
FIGS. 2A and 2B show the results of magnetic field analysis in the vicinity of the main magnetic gap. FIG. 2A is an explanatory diagram of a model to be subjected to magnetic field analysis, and FIG.
FIG. 3 is an explanatory diagram showing a relationship between a magnetic gap and an LI characteristic in the direct current reactor according to the first embodiment.
FIG. 4 is a cross-sectional side view of a DC reactor according to Embodiment 2 of the present invention.
FIG. 5 is a sectional side view of a DC reactor according to Embodiment 3 of the present invention.
FIG. 6 is a cross-sectional side view of a DC reactor according to Embodiment 4 of the present invention.
FIG. 7 is a cross-sectional side view of a direct current reactor according to a fifth embodiment of the present invention.
8A and 8B show a DC reactor according to Embodiment 6 of the present invention, in which FIG. 8A is a developed plan view of a main yoke, and FIG. 8B is a sectional side view.
FIG. 9 is a cross-sectional side view of a DC reactor according to prior art 2;
FIG. 10 is an explanatory diagram showing a temperature change of a demagnetization curve in a permanent magnet.
[Explanation of symbols]
10 E-shaped core iron core, 10C center leg, 10R right leg, 10L left leg, 11 I-shaped core iron core, 12 coils, 13, 14 Protruding auxiliary yoke, 15 Permanent magnet, 16 Gap adjusting spacer, 20 C Character forming layer iron core, 20R right leg, 20L left leg, 21 T shape layer iron core, 21C leg, 22 coils, 23, 24 Protruding auxiliary yoke, 30 C character forming layer iron core, 30R right leg, 30L left leg 31 I-shaped layer core, 32 coils, 33, 34 Protruding auxiliary yoke, 40, 41 C-shaped layer core, 42 coils, 43, 44 Protruding auxiliary yoke, 50, 51 E-shaped layer core, 50 C , 51C Central leg, 50R, 51R Right leg, 50L, 51L Left leg, 52 Coil, 53, 54 Protruding auxiliary yoke, 60H-shaped layer core, 60A Upper arm, 60B Bottom arm, 60a, 0b Tip, 60a ', 60b' Thin connection, 60C Central leg, 60R Right leg, 60L Left leg, 62 Coil, 63, 64 Protruding auxiliary yoke, Cm Magnetic pole neutral wire, G Main magnetic gap, Gs Magnetism Gap, Φc coil flux, Φm bias flux.

Claims (5)

A closed magnetic circuit type main yoke that forms a closed magnetic circuit through a main magnetic gap that is a magnetic gap, a coil that generates a magnetic flux in the closed magnetic circuit, and a bias magnetic field is applied to the magnetic flux generated by the coil In a direct current reactor including a permanent magnet,
Straddling the main magnetic gap, and then disposing the permanent magnet in a manner to be spaced apart from the main yoke, and each auxiliary on the side surface of the main yoke of a position away in the opposite Direction together from the main magnetic gap position A yoke is protruded, the permanent magnet is connected to the main yoke via the auxiliary yoke, and at least 1/2 of the main magnetic gap distance between the main yoke and the permanent magnet. A direct current reactor characterized by securing a gap. 2. The DC reactor according to claim 1, wherein an opposing area of the auxiliary yoke connected to both end magnetic pole surfaces of the permanent magnet is configured to be smaller than an opposing area of the main magnetic gap.   The main magnetic gap is formed in the vicinity of a corner portion of the main yoke where the inner and outer circumference differences in the magnetic path length inside the main yoke are different, and the permanent magnet is placed in the vicinity of the main magnetic gap and the magnetic path length is long. The DC reactor according to claim 1, wherein the direct current reactor is disposed on an outer peripheral side of the main yoke.   The bias magnetic flux generated by the permanent magnet is increased or decreased by increasing or decreasing a gap between the main yoke and the permanent magnet and increasing or decreasing a connection area between the auxiliary yoke and the permanent magnet. Item 5. The direct current reactor according to items 1 to 3.   The main yoke is constituted by a combination of one or more iron cores using a laminated iron core, or a soft magnetic ferrite bulk iron core, or a continuous molded body, according to any one of claims 1 to 4. DC reactor.

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