JP2016018929A - Reactor and direct current voltage converter using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compound type reactor which is high in inductance and difficult to be saturated magnetically, and a direct current voltage converter using the compound type reactor.SOLUTION: A reactor includes: a cylindrical first magnetic core 1; a coil 4 and a coil 5 wound around the first magnetic core 1 in such directions that generated magnetic fluxes are canceled with each other; and a second magnetic core 2 and a magnetic powder kneaded material 3 filling an internal cylindrical part of the first magnetic core 1.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a reactor used in a DC voltage converter.

  A DC voltage conversion technique for performing voltage conversion such as step-up or step-down using the mutual inductance of the reactor is known.

  Patent Document 1 describes a two-phase converter reactor which is a two-phase magnetically coupled reactor including a core, a two-phase converter coil wound around the core, and a plurality of gap plates. The core includes two T-shaped sections each having a substantially T-shaped cross section and two I-shaped sections that are straight leg sections and are constituted by another core material that is another magnetic material, and each T-shaped section. Are opposed to each other, and a central leg portion protruding inward is provided at the central portion of the inner side surface, which is the surface on the opposite side of the substantially linear base portion. A reactor is configured by arranging two end leg elements projecting inwardly provided on both sides in the width direction with respect to the central leg portion of the inner side portion of the T-shaped portion, and a converter coil on the gap plate and the I-shaped portion.

  Patent Document 2 discloses an I-type ferrite core having two parallel surfaces for the purpose of miniaturization, and two U-shaped or C-shaped members of the same shape at both end portions of the two surfaces of the I-type ferrite core. A coil in which two end faces of a core are each composed of a Fe-based alloy dust core connected through a magnetic gap, and a conductive wire is wound around the two Fe-based dust cores in the same direction and the same number of turns. An inductor for use in a two-phase interleaved control power factor correction converter is described.

JP 2012-065453 A JP 2012-204454 A

  According to the configuration of Patent Document 1, since the converter coil is arranged only in a part of the core having a substantially T-shaped cross section and the core including the I-shaped part, the part of the magnetic leg part to be wound is occupied by the magnetic circuit. There is a problem that it is limited and the self-inductance due to the increase in the number of turns cannot be increased.

  According to the configuration of Patent Document 2, there is a problem that leakage magnetic flux generated from each of the windings wound around the two U-type or C-type cores is concentrated on the I-type ferrite core and is likely to be magnetically saturated.

  That is, the conventional reactor does not have the technical idea of increasing the self-inductance by increasing the number of windings, and in many cases, the configuration is such that the winding is arranged with a part of the magnetic circuit as a magnetic leg. For this reason, the number of turns is limited, and the self-inductance value cannot be increased. In addition, if the number of turns is increased by increasing the proportion of the magnetic leg portion in the magnetic circuit, unless the entire magnetic circuit is enlarged, the cross-sectional area of the portion through which the leakage flux passes is reduced, and magnetic saturation is likely to occur. There was a problem that the leakage inductance value was also small.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a reactor in which a leakage inductance value is improved by increasing a self-inductance value and suppressing magnetic saturation, and a DC voltage converter using the reactor.

  In order to solve the above problems, the reactor of the present invention includes a cylindrical first magnetic core and two sets of winding portions wound around the first magnetic core in a direction in which generated magnetic fluxes cancel each other. And a magnetic body through which a part of the magnetic flux generated from the winding portion passes, and the magnetic body is arranged so as to fill an inner cylindrical portion of the first magnetic core formed by applying the winding portion. It is characterized by being.

  Moreover, the reactor of this invention is characterized by the said magnetic body comprising the 2nd magnetic core which consists of a molded object.

  Moreover, the reactor of this invention is characterized by the said magnetic body comprising a magnetic powder kneaded material.

  In the reactor according to the present invention, the first magnetic core is composed of two or more cylindrical bodies.

  Moreover, the reactor of this invention is characterized by the said 1st magnetic core consisting of two or more circumferential direction division bodies.

  Moreover, the DC voltage converter of this invention is characterized by using the said reactor.

  The reactor of the present invention forms a coupling inductor by forming two or more reactors by applying two or more windings to a cylindrical magnetic core and magnetically coupling them to each other.

  The DC voltage converter uses the inductance of the reactor, and it is necessary to generate as much inductance as possible in order to reduce the size required in the market.

  Therefore, the reactor of the present invention uses a cylindrical magnetic core such as a toroidal shape to increase the proportion of the winding portion in the entire magnetic circuit, thereby obtaining a larger inductance.

  Further, the leakage inductance is effectively used by adopting a configuration that is less likely to cause magnetic saturation.

  The reactor of the present invention is magnetically saturated by filling the inner cylindrical portion of the cylindrical magnetic core, that is, the hollow portion formed after winding, with a magnetic material and increasing the cross-sectional area in the direction perpendicular to the cylindrical direction. This eliminates the trade-off between self-inductance and leakage inductance.

The magnetic body that fills the inner cylindrical portion of the wound magnetic core may be, for example, a columnar magnetic core formed in advance or a magnetic powder kneaded material that is filled and cured, but the inner cylindrical portion More preferably, for example, a columnar magnetic core is disposed so as to be substantially fitted, and a magnetic powder kneaded material is filled in the generated gap and cured.
Note that a slight gap may be provided between the cylindrical magnetic core and the windings, between the windings, between the magnetic body and the windings, or the like.

  In the case of mass production, if it is difficult to prepare a high-profile cylindrical magnetic core, a plurality of cylindrical bodies, that is, low-profile cylindrical magnetic cores may be laminated and used as an integral unit.

  Similarly, in order to simplify the winding man-hours in mass production, after preparing a plurality of circumferentially divided bodies, for example, magnetic cores divided in the circumferential direction, such as semi-cylindrical divided cores, These may be integrated so as to form a hollow portion and used as a cylindrical magnetic core.

  ADVANTAGE OF THE INVENTION According to this invention, the reactor which improved the self-inductance value and the leakage inductance value, and a DC voltage converter using the same are obtained.

 Further, according to the present invention, it is possible to obtain a reactor that eliminates the trade-off between self-inductance and mutual inductance, realizes further downsizing and loss improvement, and a DC voltage converter using the reactor.

It is a perspective view which shows 1st Embodiment in the reactor of this invention. It is a partial notch perspective view which shows 2nd Embodiment in the reactor of this invention. It is sectional drawing which shows 3rd Embodiment in the reactor of this invention. It is a circuit diagram which shows 4th Embodiment in the reactor of this invention.

  Hereinafter, embodiments of the present invention will be described in detail.

(First embodiment)
FIG. 1 is a perspective view showing a first embodiment of a reactor according to the present invention.

  The first magnetic core 1 is provided with a winding portion 4 and a winding portion 5, the inner cylinder portion of the first magnetic core 1 is a magnetic body as a second magnetic core 2, and the gap between the inner cylinder portions is also a magnetic body The magnetic powder kneaded material 3 is filled and cured to constitute the reactor 100.

  The first magnetic core 1 is a toroidal core made of a FeNi dust core, and has an outer diameter of 54 mm, an inner diameter of 24 mm, and a height of 27 mm.

  The second magnetic core 2 is a cylindrical core made of FeNi dust core having the same height as the first magnetic core 1 and has an outer diameter of 16 mm and a height of 27 mm.

  The winding part 4 and the winding part 5 are made of φ2 mm copper wires, so that the generated magnetic fluxes cancel each other and occupy 90% of the magnetic circuit formed by the first magnetic core 1. It is wound by 28T.

  The magnetic powder kneaded product 3 uses 6.5% SiFe powder as magnetic powder and an epoxy resin kneaded as a binder, the first magnetic core 1 and the second magnetic core 2, and the winding part 4 and the winding part. The first magnetic core 1 and the second magnetic core 2 are integrated with each other after being filled in the gap 5.

  The self-inductance values due to energization of the winding part 4 and the winding part 5 are each 170 μH, an AC voltage is applied to the end of one winding part, the end of the other winding part is opened, and induction at the open end When the voltage was measured and the coupling coefficient between the winding portions was examined, it was about 0.5. When a direct current of 20 A was applied to each of the winding part 4 and the winding part 5 and the leakage inductance value was examined, it was about 70 μH.

  As described above, as the second magnetic core 2, a core having a shape substantially fitted to the inner cylinder portion after winding of the first magnetic core 1 is used, and the magnetic powder kneaded material 3 is filled in the gap, so that the inner cylinder portion By making the whole as a central magnetic leg portion and increasing the cross-sectional area of the central magnetic leg portion, which is a path for leakage magnetic flux, as much as possible, a reactor that is hard to be magnetically saturated is obtained.

(Second Embodiment)
FIG. 2 is a partially cutaway perspective view showing a second embodiment of the reactor of the present invention.

  This embodiment is the same as the first embodiment except for the configuration of the first magnetic core and the second magnetic core.

  The first magnetic core is formed by laminating a cylindrical core 111 and a cylindrical core 112 so that each inner cylindrical portion is continuous. The cylindrical core 111 and the cylindrical core 112 have a toroidal shape made of a FeNi powder magnetic core and having an outer diameter of 54 mm, an inner diameter of 24 mm, and a height of 27 mm.

  The second magnetic core is configured by stacking the split core 211 and the split core 212 in the height direction. The divided core 211 and the divided core 212 have a cylindrical shape with an outer diameter of 16 mm and a height of 27 mm made of a FeNi powder magnetic core.

  The winding portion 41 and the winding portion 51 are the same as those of the first embodiment, and the magnetic circuit 80 formed by the first magnetic core is formed so that the generated magnetic fluxes cancel each other. Each of them is wound by 26T so as to occupy%.

  The magnetic powder kneaded material 31 is the same as that of the first embodiment, and after being filled in the gap between the first magnetic core and the second magnetic core, and the winding portion 41 and the winding portion 51, it is cured, The first magnetic core and the second magnetic core are integrated.

  In the reactor 101 configured as described above, when the self-inductance value and the leakage inductance value were examined by the same method as in the first embodiment, they were about 330 μH and 140 μH, respectively.

  With the above configuration, the cross-sectional area constituting the magnetic circuit of the first magnetic core can be easily increased in mass production, and the self-inductance value can be increased. Similarly, in mass production, the height of the second magnetic core can be easily adjusted, and a reactor that is less likely to be magnetically saturated can be obtained.

  The cylindrical core 111 and the cylindrical core 112 preferably have the same shape in consideration of mass productivity, but cores having different heights may be used as long as the outer diameter dimension and the inner diameter dimension are equal. Further, in FIG. 2, an example of stacking two cylindrical cores is shown, but two or more cylindrical cores may be stacked to form the first magnetic core.

  The split core 211 and the split core 212 preferably have the same shape in consideration of mass productivity. Moreover, although the thing with the same cross-sectional shape of the direction perpendicular | vertical to a cylinder direction is preferable, as long as it substantially fits in the inner cylinder part after winding, you may use a core of different height. In addition, in FIG. 2, although the lamination example of two division | segmentation cores was shown, you may laminate | stack a single body or two or more division | segmentation cores. Although the split core in the height direction has been illustrated, the split magnetic core may be bundled in the circumferential direction of the inner cylinder portion to constitute the second magnetic core.

(Third embodiment)
FIG. 3 is a cross-sectional view showing a third embodiment of the reactor of the present invention, and shows a cross section in a direction perpendicular to the cylindrical direction.

  The first magnetic core forms a cylindrical body by facing the circumferentially divided core 121 and the circumferentially divided core 122 that are divided into two in the circumferential direction. The circumferentially divided core 121 and the circumferentially divided core 122 have the same shape, and have corners so that the cross-sectional shape of the first magnetic core in the direction perpendicular to the cylindrical direction becomes a square shape.

  A bobbin-equipped winding part 421 and a bobbin-equipped winding part 422, each of which is formed by winding a bobbin in advance, are inserted into the circumferentially-divided core 121 with a corner portion interposed therebetween. Similarly, a bobbin-equipped winding part 521 and a bobbin-equipped winding part 522, each of which is formed by winding a bobbin in advance, are also inserted into the circumferentially divided core 122 with a corner portion interposed therebetween.

  Next, the circumferentially divided core 121 and the circumferentially divided core 122 are integrated so that the respective corners are at diagonal positions, and the resulting inner cylindrical portion has a second magnetic core 22 and an inner Reactor 102 is configured by filling magnetic powder kneaded material 32 as a magnetic material in the gap between the cylindrical portions and curing it.

  The winding end of the bobbin-equipped winding part 421 and the winding start end of the bobbin-equipped winding part 422 are connected by a winding connecting part 61, and the winding end of the bobbin-equipped winding part 521 and the bobbin-attached winding The winding start end of the wire portion 522 is connected by the winding connection portion 62.

  The circumferentially divided core 121 and the circumferentially divided core 122 are made of FeNi powder magnetic cores, and an integrated core having a square cross section has an outer side of 35 mm × 40 mm, an inner side of 20 mm × 25 mm, and a height of 27 mm. is there.

  The second magnetic core 22 is made of a FeNi powder magnetic core, and the outer side is a prismatic core having a size of 15 mm × 20 mm and a height of 27 mm.

  Using a copper wire of φ2 mm, the winding applied to the bobbin-equipped winding part 421 and the bobbin-equipped winding part 422, and the winding applied to the bobbin-equipped winding part 521 and the bobbin-equipped winding part 522 are: The generated magnetic fluxes cancel each other and are wound by 10T so as to occupy 70% of the magnetic circuit.

  The magnetic powder kneaded material 32 is a material obtained by kneading 6.5% SiFe powder as magnetic powder and an epoxy resin as a binder, and filling and curing the gap in the inner cylinder portion.

  By setting it as the said structure, a coil | winding part can be formed simply, without impairing the technical idea of this invention, and the reactor excellent in mass-productivity is obtained.

(Fourth embodiment)
FIG. 4 is a circuit diagram showing a fourth embodiment of the reactor of the present invention, and shows a DC voltage converter using the reactor described in the first embodiment.

  Input terminal portion 71 is connected to one end 431 of winding portion 4 and one end 531 of winding portion 5 in the reactor.

  The other end 432 of the winding part 4 is connected to one end of the first switch part SW1 and the anode of the first diode D1.

  The other end 532 of the winding part 5 is connected to one end of the second switch part SW2 and the anode of the second diode D2.

  The ground potential unit GND is connected to the other end of the first switch unit SW1 and the other end of the second switch unit SW2.

  The output terminal portion 72 is connected to the cathode of the first diode D1 and the cathode of the second diode D2.

  The first switch unit SW1 is repeatedly opened and closed at a constant cycle, and the second switch unit SW2 is repeatedly opened and closed with a phase difference of 180 degrees from the first switch unit SW1.

  A voltage Vin having at least a DC component is input to the input terminal portion 71, and a voltage Vout and a current Iout having at least a DC component are output from the output terminal portion 72.

  The output voltage Vout and current Iout are smoothed by the capacitor C and consumed by the load R.

  As described above, by using the reactor of the present invention, it is possible to obtain a DC voltage converter that realizes further miniaturization and loss improvement.

  In the above-described embodiment, each magnetic core is exemplified by a FeNi dust core. However, a generally used soft magnetic material such as pure iron or a Fe-Si based dust core, or MnZn ferrite is used. Also good. In particular, a dust core using a soft magnetic material having a saturation magnetic flux density of 0.8 T or more is preferable.

  In the above-described embodiment, the toroidal shape or the square-shaped core is exemplified as the first magnetic core, but any shape can be used as long as it becomes a cylindrical core by itself or in combination. it can.

  In the above-described embodiment, a φ2 mm copper wire is used as the winding. However, the material and thickness can be selected as needed as long as the winding is generally used as a winding.

  The ratio of the winding to the magnetic legs of the first magnetic core is large. For example, when the winding is applied to the first magnetic core without a gap, a part of the magnetic flux generated from the winding portion when energized, that is, the leakage magnetic flux is It will not pass through the inner cylinder.

  On the other hand, if the ratio of the windings occupying the magnetic legs of the first magnetic core is reduced, not only the necessary inductance cannot be secured, but also the one winding and the other winding applied to the first magnetic core. The magnetic coupling is reduced, and the effect of suppressing the amplitude of the winding current due to the mutual magnetic coupling cannot be obtained, thereby increasing the AC loss in the magnetic core and the winding.

  Therefore, the effective permeability of the magnetic leg on one winding side is μ1, the cross-sectional area is S1, the effective permeability of the magnetic leg on the other winding side is μ2, the cross-sectional area is S2, and one winding is When the effective permeability of the portion connected to the magnetic body filling the inner cylinder portion is μi and the cross-sectional area is Si from the gap formed between the first winding portion and the other winding portion, Fo = (μ1 · S1 + μ2 · S2) / 2, and Fi = μi · Si, it is desirable that 0.5Fo <Fi <3Fo.

  When the reactor of the present invention is connected to the DC voltage conversion circuit shown in the fourth embodiment, in order to perform the function of step-up or step-down, the average value of the current flowing through the winding portion is Iave and the amplitude is ΔIp− When p, it is desirable to adjust the gap so that 0.3 <ΔIp−p / Iave <0.5.

  In the above-described embodiment, the reactor having one set of winding portions has been illustrated. However, one or more sets of windings have the same shape and an even number so that the flux linkage can be easily canceled by magnetic coupling. May be provided.

  Furthermore, a reactor provided with two winding portions having the same shape is preferable. The coupling coefficient of the winding part is more preferably about 0.5.

  As mentioned above, although the Example of this invention was described, this invention is not limited above, The change and correction of a structure are possible in the range which does not deviate from the summary of this invention. That is, various changes and modifications that can be made by those skilled in the art are also included in the present invention.

DESCRIPTION OF SYMBOLS 1 1st magnetic core 111,112 Cylindrical core 121,122 Circumference division | segmentation core 2,22 2nd magnetic core 211,212 Division | segmentation core 3,31,32 Magnetic powder kneaded material 4,41,5,51 Winding part 421, 422, 521, 522 Winding portion with bobbin 431, 531 One end of winding portion 432, 532 The other end of winding portion
61, 62 Winding connection part 71 Input terminal part 72 Output terminal part 100, 101, 102 Reactor SW1 First switch part SW2 Second switch part D1 First diode D2 Second diode C Capacitor R Load GND Ground potential part

Claims (6)

  A cylindrical first magnetic core, two sets of winding portions wound around the first magnetic core in a direction in which the generated magnetic flux cancels each other, and a part of the magnetic flux generated from the winding portion passes. It is a reactor provided with the magnetic body to perform, Comprising: The said magnetic body is distribute | arranged so that the inner cylinder part of the said 1st magnetic core which gives the said coil | winding part may be satisfy | filled.   The reactor according to claim 1, wherein the magnetic body includes a second magnetic core made of a molded body.   The reactor according to claim 1, wherein the magnetic body comprises a magnetic powder kneaded material.   The reactor according to any one of claims 1 to 3, wherein the first magnetic core includes two or more cylindrical bodies.   The reactor according to claim 1, wherein the first magnetic core includes two or more circumferentially divided bodies.   A direct-current voltage converter comprising the reactor according to any one of claims 1 to 5.

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