JP2008159817A - Reactor and power supply device using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reactor being hard to saturate and being of low loss and low cost. <P>SOLUTION: The reactor 10 has: a toroidal core 11; a first winding 12 wound on the toroidal core 11 in the fixed number of turns; and a second winding 13 wound on the toroidal core 11 in the same number of turns as the first winding 12. The directions of the first to second windings 12 and 13 are set so that a magnetic flux generated in a toroidal core 11 is offset when a current is made to flow through the first and second windings 12 and 13. Since an inductance by a leakage-flux component passing no toroidal core 11 is generated between terminals 12b and 13b for the winding in this case, the small-sized reactor being extremely hard to saturate is provided. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a reactor and a power supply device using the same, and in particular, relates to a reactor winding structure suitable for a large current application, and a power supply device using this reactor.

  In systems such as HEV (Hybrid Electric Vehicle), EV (Electric Vehicle), solar power generation, small wind power generation, and fuel cell power generation, passive components such as DC voltage step-up / down circuits, DC / AC conversion circuits (inverters), filter circuits, etc. A reactor is used as a part. It is required that this reactor does not saturate even when a large current flows, and that there is little loss.

  Patent Document 1 discloses a reactor using a silicon steel plate as a core material. The saturation magnetic flux density of a silicon steel plate is as high as about 2T, and a low noise reactor can be realized, but there is also a problem that loss at high frequencies is large. However, the reactor described in Patent Document 1 uses a core member formed by laminating a band of silicon steel sheets and winding the band in a circular ring shape so that the cross-sectional shape thereof is circular. Is realized.

As the core material of the reactor, an amorphous core, a ferrite core and the like are known in addition to the silicon steel plate. Among these, the amorphous core has a problem that the saturation magnetic flux density is relatively high and the loss at high frequency is small, but it is difficult to process, and vibration is generated by applying high frequency, resulting in a large noise. In addition, the ferrite core has various advantages such as low loss, low noise, low cost, and easy processing, but is not suitable for large current applications because of its low saturation magnetic flux density.
JP 2002-203729 A

  Thus, as a core material of a conventional reactor, a silicon steel plate having a high saturation magnetic flux density and suitable for a large current application is preferably used. However, even if the silicon steel sheet is thinned, there is a problem that loss at high frequencies is large. In addition, silicon steel plates have various disadvantages such as high material costs and difficulty in processing. Therefore, there is a demand for a new reactor that has low loss and low noise and is excellent in cost and processing.

  Accordingly, an object of the present invention is to provide an inexpensive reactor that is hard to be saturated and has a low loss.

  Another object of the present invention is to provide a high-performance power supply device configured using such a reactor.

  The object of the present invention is to provide a core member made of a magnetic material, a first winding wound around the core member, and a second winding wound around the core member and connected to the first winding. And when the current flows through the first and second windings, the first and second windings are oriented so that the magnetic fluxes generated in the core member by the first and second windings cancel each other. Is achieved by a reactor characterized in that is set.

  When a current is passed through the first and second windings, the magnetic fluxes generated in the core member by the first and second windings cancel each other, but a leakage magnetic flux component that does not pass through the core member is generated, and the two terminals Inductance occurs between them. This inductance is equivalent to a coil made through a large air gap, and since it can be considered that the gap is dispersed as a whole, it is possible to realize a small coil that is hardly saturated. Further, since this inductance is hardly affected by the magnetic permeability variation of the core, a reactor having excellent temperature characteristics can be realized.

  In the present invention, the core member is preferably a ferrite core. Since ferrite has a low saturation magnetic flux density, it is not preferable as a core material for large current applications. However, by adopting the above-described winding structure using the first and second windings 12 and 13, the saturation magnetic flux density can be reduced. The problem can be solved and the advantages of ferrite such as low loss, low noise, low cost, and ease of processing can be utilized even in high current applications.

  In the present invention, it is preferable that the first and second windings are made of a single conductor. According to this, the operation | work which connects the ends of the 1st and 2nd windings becomes unnecessary.

  In the present invention, it is preferable that the core member constitutes a substantially closed magnetic circuit. Further, the first winding is concentratedly wound at a predetermined position of the core member, and the second winding is concentratedly wound at a predetermined position of the core member different from the position of the first winding. It is preferable that According to this, formation of the coil | winding to a core member becomes easy and the influence which the leakage magnetic flux of one coil has with respect to the other coil can be suppressed. Note that the term “substantially closed magnetic circuit” means that not only a completely closed magnetic circuit but also a closed magnetic circuit having a gap is allowed.

  The object of the present invention is also characterized by comprising a DC power supply, a switching circuit for switching a DC current supplied from the DC power supply, and the reactor inserted between the DC power supply circuit and the switching circuit. This is also achieved by a power supply.

  Thus, according to the present invention, it is possible to provide an inexpensive reactor that is less likely to be saturated and has low loss.

  Moreover, according to this invention, the high performance power supply device comprised using the reactor which has said characteristic can be provided.

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

  FIG. 1 is a schematic perspective view showing an external structure of a reactor according to a preferred embodiment of the present invention. FIG. 2 is a schematic plan view of the reactor shown in FIG.

  As shown in FIGS. 1 and 2, the reactor 10 includes a toroidal core 11, a first winding 12 wound around the toroidal core 11 with a predetermined number of turns, and a first winding 12 around the toroidal core 11. Are provided with a second winding 13 wound with the same number of turns, and an insulating plate 14 that partitions the first winding 12 and the second winding 13.

  Ferrite is used for the magnetic material of the toroidal core 11. As described above, since ferrite has a low saturation magnetic flux density, it is not preferable as a core material for large current applications. However, by adopting the following winding structure using the first and second windings 12 and 13, the problem of saturation magnetic flux density can be solved, and low loss and low noise can be achieved even in large current applications. It is possible to take advantage of ferrite such as low cost and ease of processing.

The first winding 12 constitutes a _first choke coil L1, and the second winding 13 constitutes a _second choke coil L2. The first winding 12 is concentratedly wound on the left side of the toroidal core 11 and the second winding 13 is concentrated on the right side, and an insulating plate 14 is provided between them. This insulating plate 14 is provided to ensure insulation between the _two coils L ₁ and L ₂ . The first and second windings 12 and 13 are preferably rectangular conductors. This is because the flat conducting wire has a large cross-sectional area and can efficiently wind the winding.

The directions of the first and second windings 12 and 13 are the same, the magnetic flux Φ ₁ generated in the toroidal core 11 when a current flows through the first winding 12, and the current in the second winding 13. Is configured so that the magnetic flux Φ ₂ generated when the current flows through each other cancel each other. Such a configuration is generally called a common mode filter or a line filter.

In this embodiment, one end 12a of the first winding 12 and one end 13a of the second winding 13 is connected, a coil L ₁ and a coil L ₂ is in the series-connected configuration. In other words, this is the same as the configuration in which the two output terminals of the common mode filter are short-circuited. The other ends 12 b and 13 b of the first and second windings are used as input / output terminals of the reactor 10. Note that the first and second windings 12 and 13 may be formed of a single conducting wire. This is because the work of connecting the ends of the first and second windings can be eliminated, and a simple and highly reliable winding structure can be obtained.

When supplying a current to the series circuit of the choke coil _L 1, _{L 2,} the magnetic flux all the magnetic flux produced by the choke coil _L 1, _{L 2} is if flows through the middle toroidal core 11, made with a coil _L 1, _{L 2} is Since they are opposite and equal to each other, they cancel each other. Therefore, when the inductance between the two terminals is measured in such a state, it should be zero.

  However, if the first and second windings 12 and 13 are divided into left and right as shown in the drawing, a magnetic flux component that does not actually pass through the toroidal core (see the broken line in FIG. 2) is generated. Inductance occurs between terminals. Conventionally, this type of inductance is called “leakage inductance” or “parasitic inductance” and is an unintended inductance component. However, the leakage inductance can be regarded as equivalent to a coil made through a large air gap, and thus has the same characteristics as a core with a gap. However, in reality, since it is realized without providing a local gap like a normal core with a gap, it has very excellent characteristics. That is, since it can be considered that the gap is dispersed as a whole, it is possible to realize a small reactor that is hardly saturated. In addition, the air gap effect makes it less susceptible to changes in the magnetic permeability of the core, and the inductance is less dependent on the core characteristics. Therefore, a reactor having excellent temperature characteristics can be realized.

  As described above, according to the reactor 10 of the present embodiment, the magnetic flux generated in the toroidal core 11 when the current flows through the first and second windings 12 and 13 wound around the toroidal core 11 is canceled out. As described above, since the orientations of the first and second windings 12 and 13 are set, inductance due to a leakage magnetic flux component that does not pass through the toroidal core 11 can be generated, and a small size that is very difficult to saturate. A reactor can be realized.

  The shape of the core used for the reactor of the present invention is not limited to the toroidal core, and various shapes can be adopted.

  FIG. 3 is a schematic perspective view showing the external structure of the reactor according to the second embodiment of the present invention. FIG. 4 is a schematic plan view of the reactor shown in FIG.

As shown in FIGS. 3 and 4, the reactor 20 includes a first U-shaped core 21 around which the first winding 12 is wound, and a second around which the second winding is wound. It is configured by combination with the U-shaped core 22. The tips of the U-shaped cores 21 and 22 are connected to each other, thereby forming a closed magnetic circuit without an air gap. The first winding 12 and the second winding 13 are wound around the same linear core portion, and are arranged side by side. The directions of the first and second windings 12 and 13 are the same, and one end 12a of the first winding 12 and one end 13a of the second winding 13 are connected. The other ends 12 b and 13 b of the first and second windings constitute the input / output end of the reactor 20. When the current flows through the first and second windings 12 and 13, the first and second windings 12 and 13 cause the magnetic fluxes Φ ₁ and Φ ₂ generated in the core member to cancel each other out. And the direction of the second winding is set.

  FIG. 5 is a schematic plan view showing the configuration of the reactor according to the third embodiment of the present invention, and shows a modification of the reactor 20 shown in FIGS. 3 and 4.

As shown in FIG. 5, the reactor 30 is different from the reactor 20 described above in that the directions of the first winding 12 and the second winding 13 are opposite to each other. On the other hand, the connection relationship between the first winding 12 and the second winding 13 is also different, and one end 12a of the first winding 12 and the other end 13b of the second winding 13 are connected. The other end 12b of the first winding and the one end 13a of the second winding constitute the input / output end of the reactor 30. Therefore, as a whole, the first and second windings 12 are so arranged that the magnetic fluxes Φ ₁ and Φ ₂ generated in the core member are canceled when a current is passed through the first and second windings 12 and 13. , 13 directions are set.

  Thus, according to the reactor 20 and 30 which concern on 2nd and 3rd embodiment, when an electric current is sent through the 1st and 2nd coil | windings 12 and 13 wound by the core member, in a core member. Since the directions of the first and second windings 12 and 13 are set so that the generated magnetic flux is canceled out, inductance due to a leakage magnetic flux component that does not pass through the core member can be generated and is very saturated. It is possible to realize a small and difficult reactor.

  FIG. 6 is a schematic plan view showing the configuration of the reactor 40 according to the fourth embodiment of the present invention.

  As shown in FIG. 6, the reactor 30 is also configured by a combination of two U-shaped cores 41 and 42, and the first winding 12 and the second winding 13 are linearly opposed to each other. It is characterized by the fact that it is wound around each core part and is placed face to face. The first winding 12 has one connection point of the two U-shaped cores 41 and 42, and the second winding 13 has the other connection point. One end 12a of the first winding 12 and one end 13a of the second winding 13 are connected, and the other ends 12b and 13b of the first and second windings constitute an input / output end of the reactor 20. Yes. When the current flows through the first and second windings 12 and 13, the first and second windings 12 and 13 cause the magnetic fluxes generated in the core member to cancel each other. Winding direction is set.

  As described above, the reactor 40 according to the fourth embodiment also cancels out the magnetic flux generated in the core member when current is passed through the first and second windings 12 and 13 wound around the core member. In addition, since the directions of the first and second windings 12 and 13 are set, it is possible to generate an inductance due to a leakage magnetic flux component that does not pass through the core member, and to realize a small reactor that is not very saturated. be able to.

  FIG. 7 is a circuit diagram showing an example of a power supply device using the reactor according to the present invention.

As shown in FIG. 7, the power supply device 50 has a circuit configuration in which a DC power supply 51, a step-up chopper circuit 52, a PWM inverter 53 as a switching circuit, and a smoothing filter 54 are sequentially connected. The reactors 10 to 40 shown in the above-described embodiments are used as the reactor Lc in the boost chopper circuit 52 and the reactors L _S1 and L _S2 in the smoothing filter 54. As described above, in the power supply device 50 of the present embodiment, a high-performance power supply device is inserted between the DC power supply and the switching circuit because the reactor is not saturated even when a large current is passed and the loss is small. Can be realized.

  The present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the present invention, and these are also included in the scope of the present invention. Needless to say.

  For example, in the above-described embodiment, the reactor is configured using a core without a gap, but may be configured using a core having a gap.

FIG. 1 is a schematic perspective view showing an external structure of a reactor 10 according to a preferred embodiment of the present invention. Also, FIG. 2 is a schematic plan view of reactor 10 shown in FIG. FIG. 3 is a schematic perspective view showing the external structure of the reactor 20 according to the second embodiment of the present invention. 4 is a schematic plan view of the reactor 10 shown in FIG. FIG. 5 is a schematic plan view showing the configuration of the reactor 30 according to the third embodiment of the present invention, and shows a modification of the reactor 20 shown in FIGS. 3 and 4. FIG. 6 is a schematic plan view showing the configuration of the reactor 40 according to the fourth embodiment of the present invention. FIG. 7 is a circuit diagram showing an example of a power supply device using the reactor according to the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Reactor 11 Toroidal core 12 1st coil | winding 12a One end 12b of the 1st coil | winding 13 The other end 13 of the 1st coil | winding 13a 2nd coil | winding 13a End 14 Insulating plate 20 Reactor 21 U-shaped core 22 U-shaped core 30 Reactor 40 Reactor 41 U-shaped core 42 U-shaped core 50 Power supply 51 DC power supply 52 Boost chopper circuit 53 PWM inverter 54 Smoothing filter L ₁ first choke coil L ₂ second choke coil Φ ₁ magnetic flux due to first choke coil ₂ magnetic flux due to second choke coil Lc reactor L _S1 in boost chopper circuit 52 reactor L _S2 in smoothing filter 54 Reactor in smoothing filter 54

Claims (6)

A core member made of a magnetic material;
A first winding wound around the core member;
A second winding wound around the core member and connected to the first winding;
The direction of the first and second windings so that when the current flows through the first and second windings, the magnetic fluxes generated in the core member by the first and second windings cancel each other. The reactor is characterized by being set.   The reactor according to claim 1, wherein the core member is a ferrite core.   The reactor according to claim 1, wherein the first and second windings are made of a single conducting wire.   The reactor according to any one of claims 1 to 3, wherein the core member constitutes a substantially closed magnetic circuit.   The first winding is concentratedly wound at a predetermined position of the core member, and the second winding is concentrated at a predetermined position of the core member different from the position of the first winding. The reactor according to any one of claims 1 to 4, wherein the reactor is wound.   A DC power supply, a switching circuit for switching a DC current supplied from the DC power supply, and the reactor according to any one of claims 1 to 5 inserted between the DC power supply circuit and the switching circuit. A power supply apparatus comprising:

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