WO2016208144A1

WO2016208144A1 - Reactor

Info

Publication number: WO2016208144A1
Application number: PCT/JP2016/002826
Authority: WO
Inventors: 朝日　俊行; 小谷　淳一; 寛範長崎; 伸哉松谷; 浩史冨田; 植松　秀典
Original assignee: パナソニックＩｐマネジメント株式会社
Priority date: 2015-06-25
Filing date: 2016-06-13
Publication date: 2016-12-29

Abstract

Provided is a reactor comprising the following: a first coil; a second coil disposed so as to be parallel to the first coil; a connected conductor connected to the first coil and the second coil; a first terminal connected to the first coil; a second terminal connected to the second coil; and a magnetic shielding member disposed between the first coil and the second coil. The first terminal, the first coil, the connected conductor, the second coil and the second terminal are electrically connected in series in this order. The reactor can reduce the increase of the alternating-current resistance when high-frequency current flows to the coil.

Description

Reactor

The present invention relates to a reactor that is a passive element using inductance.

A reactor is known in which a current flows through two coils so as to branch from the input side, and then a current is output from each coil. Furthermore, a reactor in which a coupling coefficient adjusting means for adjusting a coupling coefficient between two coils is arranged between the two coils is known. The coupling coefficient adjusting means is made of a nonmagnetic metal such as aluminum. A configuration is also known in which a magnetic shielding plate is placed and then sealed with a sealing resin as a filler when the coil is housed in a chassis (see Patent Document 1, especially FIG. 2 and FIG. 7). This reactor is obtained by magnetically coupling two coils via a core like a transformer, and is used by adjusting the magnetic coupling coefficient between the two coils.

A reactor having two coils that are directly connected electrically is known. A configuration is also known in which a sensor holder is disposed between the two coils (see Patent Document 2). In this reactor, a sensor holder that holds a sensor for measuring a physical quantity of the reactor is disposed between two coils.

JP 2014-127637 A JP 2014-93375 A

The reactor includes a first coil, a second coil arranged in parallel with the first coil, a connection conductor connected to the first coil and the second coil, a first terminal connected to the first coil, A second terminal connected to the second coil; and a magnetic shielding member disposed between the first coil and the second coil. The first terminal, the first coil, the connection conductor, the second coil, and the second terminal are electrically connected in series in this order.

This reactor can reduce the increase in AC resistance when high-frequency current flows through the coil.

FIG. 1 is an exploded perspective view of a reactor in the first embodiment. FIG. 2 is an overall perspective view of the reactor in the first embodiment. 3 is a cross-sectional view taken along line 3-3 of the reactor shown in FIG. FIG. 4A is a top view of the reactor in the first embodiment. FIG. 4B shows the resistance of the reactor in the first embodiment. FIG. 5 is a diagram showing another magnetic shielding member of the reactor in the first embodiment. FIG. 6 is a diagram showing a magnetic shielding member of still another reactor in the first embodiment. FIG. 7 is a cross-sectional view of the reactor in the second embodiment. FIG. 8 is a perspective view of the reactor in the third embodiment. FIG. 9 is a perspective view of the reactor in the fourth embodiment.

The effect of the proximity effect on the coil is large. In the case of a reactor in which two coils are electrically connected in series and arranged in parallel spatially, it is particularly susceptible to a large loss due to the proximity effect, that is, an increase in resistance. appear. In particular, when the current becomes a high frequency, the influence becomes significant.

Generally, when a conductor is arranged in the vicinity of a coil, an eddy current is generated in the conductor due to a magnetic field from the coil, and the loss of the reactor increases due to the eddy current.

Especially, when the current flowing through the reactor becomes high frequency, even if the influence of the loss due to the eddy current is taken into account, it is possible to suppress the loss as a whole by blocking the magnetic field between the two coils to suppress the proximity effect.

The reactor described in Patent Document 1 has two coils, but is not electrically connected directly.

The reactor sensor holder described in Patent Document 2 only needs to have a size necessary to hold the sensor.

The above Patent Document 1 and Patent Document 2 do not mention an increase in AC resistance when high-frequency AC flows through a reactor in which two coils are electrically connected in series.

∙ AC loss occurs when high-frequency current flows through the reactor. The higher the current, the higher the AC loss. One cause is that the skin effect in the conductor, that is, the high frequency alternating current tends to flow only on the surface of the conductor, thus increasing the resistance. Another cause is that the proximity effect, that is, the magnetism due to the current flowing through a part of the conductor affects the other part of the conductor, thereby causing a bias in the current density distribution and increasing the resistance.

When an alternating current flows through the coil, an eddy current is generated in the metal plate arranged in the vicinity of the coil. Since eddy currents lead to coil losses, metal plates are usually not placed near the coil if possible.

The reactor in the following embodiments has an effect of reducing an increase in AC resistance when a high-frequency current flows through the reactor based on the above.

(Embodiment 1)
FIG. 1 is an exploded perspective view of a reactor 10 in the first embodiment. FIG. 2 is an overall perspective view of the reactor 10. FIG. 3 is a cross-sectional view taken along line 3-3 of reactor 10 shown in FIG. FIG. 4A is a top view of the reactor 10.

The reactor 10 includes a coil 31, a coil 32, a connection conductor 33, a terminal 36, a terminal 37, and a magnetic shielding member 40.

The coil 31, the coil 32, the connection conductor 33, the terminal 36, and the terminal 37 are made of continuous conductors. The continuous conductor may be a single conductor.

The coil 31 and the coil 32 are each made of a conductor wound around winding

axes

31C and 32C. The end 31 A of the coil 31 is connected to the connection conductor 33, and the end 31 B of the coil 31 is connected to the terminal 36. An end 32 A of the coil 32 is connected to the connection conductor 33, and an end 32 B of the coil 32 is connected to the terminal 37. The terminal 36, the coil 31, the connection conductor 33, the coil 32, and the terminal 37 are electrically connected in series in this order. The coil 31 and the coil 32 are arranged in parallel. That is, the

coils

31 and 32 are arranged so that the winding shaft 31C of the coil 31 and the winding shaft 32C of the coil 32 are spatially parallel to each other. In Embodiment 1, as shown to FIG. 4A, the part located in the coil 31 of the winding shaft 31C and the part located in the coil 32 of the winding shaft 32C comprise a pair of opposite side of rectangular PE. The coil 31 and the coil 32 have a cylindrical shape having a circular front shape as shown in FIG. 3, but are not limited to this. You may have the extending polygonal cylinder shape.

The magnetic shielding member 40 is disposed between the coil 31 and the coil 32. The magnetic shielding member 40 is made of a nonmagnetic material. As shown in FIGS. 3 and 4A, when the coil 32 is seen through the coil 31, the outer shape of the magnetic shielding member 40 is located outside the outer shape of the coil 32. On the contrary, when the coil 32 is seen through, the outer shape of the magnetic shielding member 40 is located outside the outer shape of the coil 31. An arbitrary portion of the coil 31 faces an arbitrary portion of the coil 32 through the magnetic shielding member 40. In other words, when the magnetic shielding member 40 is a flat plate, the magnetic shielding member 40 shields between the coil 31 and the coil 32. However, the magnetic shielding member 40 may not completely shield between the coil 31 and the coil 32. Since the magnetic shielding member 40 effectively shields the magnetism generated from the coil 31 and the magnetism generated from the coil 32, an increase in the AC resistance of the reactor 10 due to the proximity effect between the

coils

31 and 32 is reduced. In FIG. 1 to FIG. 4A, when the coil 32 is seen through the coil 32, the outer shape of the magnetic shielding member 40 is positioned outside the outer shape of the coil 32. A part of the outer shape may be at the same position.

The reactor 10 may further include a chassis 20, a filler 50, and a core 60.

The chassis 20 holds the coil 31, the coil 32, and the connection conductor 33 directly or indirectly. For example, the coil 31, the coil 32, and the connection conductor 33 may be held by a holding portion formed in the chassis 20. Or you may hold | maintain the coil 31, the coil 32, and the connection conductor 33 with the separate holding member arrange | positioned at the chassis 20, respectively. The chassis 20 is preferably made of a metal in order to improve the heat dissipation of the reactor 10, and more preferably made of a metal having a good thermal conductivity such as aluminum.

The filler 50 is filled in the chassis 20 and covers the coil 31, the coil 32, and the magnetic shielding member 40. A part of the magnetic shielding member 40 may be exposed from the filler 50. The filler 50 is made of resin. Specifically, the filler 50 is obtained by curing a fluid or semi-fluid resin. The filler 50 is made of, for example, a mixture of silicon resin, epoxy resin, and insulating powder. The filler 50 may contain magnetic powder. The filler 50 has a function of sealing the coil 31 and the coil 32 and the magnetic shielding member 40. 1 and 4A, the filler 50 is not shown.

The core 60 is made of a magnetic material. Although the coil 31 and the coil 32 are spatially arranged in parallel by the core 60, they have electrical characteristics close to the electrical characteristics of the coils arranged spatially in series. The coil 31 and the coil 32 are wound around the core 60. In the figure, the cross section of the core 60 has a quadrangular shape, but may have a circular shape. The cross-sectional shape of the core 60 is preferably matched to the winding shape which is a cross-sectional shape perpendicular to the winding

axes

31C and 32C of the coil 31 and the coil 32. The core 60 may be divided into a core 61 and a core 62 so as to be easily assembled. By dividing the core 60, the coil 31 and the coil 32 are manufactured and then combined with the core 61 and the core 62, thereby obtaining a configuration in which the

coils

31 and 32 are wound around the core 60.

FIG. 4B shows the resistance of the reactor 10 in the first embodiment. In FIG. 4B, the vertical axis represents the resistance of the reactor 10, and the horizontal axis represents the frequency of the voltage applied to the

coils

31 and 32. FIG. 4B shows the resistance R10 of the reactor 10 according to the first embodiment and the resistance R20 of the reactor of the comparative example that does not include the magnetic shielding member 40. In the reactor 10 according to the first embodiment illustrated in FIG. 4B, the

coils

31 and 32 have a rectangular cylindrical shape having a rectangular cross section instead of the cylindrical shape having a circular cross section illustrated in FIG. 1. The reactor of the comparative example has the same configuration as the reactor 10 except that the magnetic shielding member 40 is not provided.

As shown in FIG. 4B, at a frequency of 100 kHz, the resistance R20 of the reactor of the comparative example is 20.7 mΩ, whereas the resistance R10 of the reactor 10 according to the first embodiment is 19.1 mΩ, which is that of the comparative example. It is 7.7% less than the resistance R20 of the reactor. At a frequency of 500 kHz, the resistance R20 of the reactor of the comparative example is 103 mΩ, whereas the resistance R10 of the reactor 10 according to the first embodiment is 94.8 mΩ, which is 8.0 compared to the resistance R20 of the reactor of the comparative example. %decreasing. As shown in FIG. 4B, when the frequency is increased, the resistance R10 of the reactor according to the first embodiment is greatly reduced as compared with the resistance R20 of the reactor of the comparative example.

The temperature of the reactor 10 according to the first embodiment including the magnetic shielding member 40 made of aluminum and the reactor of the comparative example were compared. In the reactor of the comparative example, almost the

entire coils

31 and 32 were 199 ° C. or higher, and particularly the portion on the opposite side of the bottom of the chassis 20 was 210 ° C. or higher. On the other hand, in the reactor 10 according to the first embodiment, almost the

entire coils

31 and 32 were less than 200 ° C., and the portion on the opposite side of the bottom of the chassis 20 was also less than 200 ° C.

Also, the loss of the reactor 10 according to the first embodiment and the reactor of the comparative example were compared. In the reactor 10 according to the first embodiment shown in Table 1, the

coils

31 and 32 have a rectangular cylindrical shape having a rectangular cross section instead of the cylindrical shape having a circular cross section shown in FIG. The reactor of the comparative example has the same configuration as the reactor 10 except that the magnetic shielding member 40 is not provided. Table 1 shows the result of the simulation of the reactor loss when a current having a DC component of 70 A and an AC component having a frequency of 100 kHz and an effective value of 30 A is passed through the reactor.

As shown in Table 1, the reactor 10 according to the first embodiment has a larger shield loss due to the electromagnetic shielding member 40 than the reactor of the comparative example. However, the coil loss due to the

coils

31 and 32 itself is reduced because the influence of the proximity of the

coils

31 and 32 is reduced to reduce the coil AC loss. Therefore, the reactor 10 according to the first embodiment has a smaller loss as a whole than the reactor of the comparative example. In addition, the alternating current resistance value of the simulation result shown in Table 1 does not match the alternating current resistance value shown in FIG. 4B. The reason is that the reactor coil in the simulation shown in Table 1 and the reactor coil from which the result shown in FIG. 4B is obtained have the same basic coil structure, but specific coil values (coil windings). This is because the diameter, the cross-sectional dimension of the coil wire, the number of turns of the coil, etc. are different.

Thus, compared with the reactor of the comparative example, the reactor 10 according to the first embodiment reduces not only the effect of heat conduction by the magnetic shielding member 40 but also the loss by reducing the resistance of the

coils

31 and 32 in the high frequency band. Can be made.

FIG. 5 shows another magnetic shielding member 40A of the reactor 10 in the first embodiment. Although the magnetic shielding member 40 has a flat plate shape as described above, a plurality of holes 41 are formed. Similarly to the magnetic shielding member 40, the magnetic shielding member 40 A in which the plurality of holes 41 are formed can reduce an increase in the AC resistance of the reactor 10. In the magnetic shielding member 40A, the filling material 50 before curing passes through the plurality of holes 41, so that the filling material is separated between the space on the coil 31 side divided by the magnetic shielding member 40 and the space on the coil 32 side. An amount of 50 and density deviation are unlikely to occur.

FIG. 6 partially shows still another magnetic shielding member 40B of the reactor 10 according to the first embodiment. The magnetic shielding member 40 B has a net shape composed of a plurality of vertical lines 42 and a plurality of horizontal lines 43. A region surrounded by the vertical lines 42 adjacent to each other and the horizontal lines 43 adjacent to each other corresponds to the holes 41 of the magnetic shielding member 40A shown in FIG. Both the plurality of vertical lines 42 and the plurality of horizontal lines 43 are made of a nonmagnetic material such as aluminum. The magnetic shielding member 40 B also reduces the increase in AC resistance of the reactor 10. Further, the amount and density of the filler 50 are less likely to be uneven between the space on the coil 31 side separated by the magnetic shielding member 40B and the space on the coil 32 side.

(Embodiment 2)
FIG. 7 is a front cross-sectional view of reactor 10A in the second embodiment. In FIG. 7, the same components as those of the reactor 10 in the first embodiment shown in FIGS. 1 to 6 are denoted by the same reference numerals. Reactor 10A in the second embodiment is different from reactor 10 in the first embodiment in that magnetic shielding member 40 is in contact with chassis 20. When the magnetic shielding member 40 is in contact with the chassis 20, the heat transmitted to the magnetic shielding member 40 is easily transmitted to the chassis 20, and the heat dissipation characteristics of the reactor 10 are improved. Reactor 10A in the second embodiment has the same effect as reactor 10 in the first embodiment.

Note that, in the reactor 10 A according to the second embodiment, it is preferable that the reactor 10 includes the filler 50 and the core 60, similarly to the reactor 10 according to the first embodiment. Furthermore, the magnetic shielding member 40 may be the magnetic shielding member 40A or the magnetic shielding member 40B shown in FIG. 5 or FIG.

(Embodiment 3)
FIG. 8 is a perspective view of reactor 10B in the third embodiment. In FIG. 8, the same components as those of the reactor 10 in the first embodiment shown in FIGS. 1 to 6 are denoted by the same reference numerals. Reactor 10B includes a chassis 20A made of the same material as chassis 20, instead of chassis 20 of reactor 10 in the first embodiment. The chassis 20A has a flat plate shape. Reactor 10B in the third embodiment has the same effect as reactor 10 in the first embodiment.

(Embodiment 4)
FIG. 9 is a perspective view of reactor 10C in the fourth embodiment. In FIG. 9, the same components as those in reactor 10B in the third embodiment shown in FIG. Reactor 10C includes a chassis 20B made of the same material as chassis 20A, instead of chassis 20A of reactor 10B in the third embodiment. The chassis 20B has a shape in which a flat plate and a side plate are combined. Reactor 10B in the third embodiment has the same effect as reactor 10 in the first embodiment.

In addition,

reactors

10B and 10C in the third and fourth embodiments may further include a filler 50 and a core 60 in the same manner as reactor 10 in the first embodiment. Furthermore, the magnetic shielding member 40 may be the magnetic shielding member 40A or the magnetic shielding member 40B shown in FIG. 5 or FIG.

In the

reactors

10B and 10C in the third and fourth embodiments, the magnetic shielding member 40 may be separated from the chassis 20 in the same manner as the reactor 10 in the first embodiment. However, when the magnetic shielding member 40 is brought into contact with the chassis 20 similarly to the reactor 10A in the second embodiment, the heat dissipation characteristics of the

reactors

10B and 10C can be improved.

10, 10A-10C Reactor 20 Chassis 31 Coil (first coil)
31C reel (first reel)
32 coil (second coil)
32C reel (second reel)
33 Connection conductor 36 Terminal (first terminal)
37 terminals (second terminal)
40, 40A, 40B Magnetic shielding member 41 Hole 50 Filler 60 Core 61 Core 62 Core

Claims

A first coil;
A second coil disposed in parallel with the first coil;
A connection conductor connected to the first coil and the second coil;
A first terminal connected to the first coil;
A second terminal connected to the second coil;
A magnetic shielding member disposed between the first coil and the second coil;
With
A reactor in which the first terminal, the first coil, the connection conductor, the second coil, and the second terminal are electrically connected in series in this order.
When the magnetic shielding member is seen through the other from any one of the first coil and the second coil, the outer shape of the magnetic shielding member is the same as or outside of the other outer shape, The reactor according to claim 1.
The reactor according to claim 1, wherein the magnetic shielding member is made of metal and has a plurality of holes.
The reactor according to claim 3, wherein the magnetic shielding member has a net shape.
A chassis that directly or indirectly holds the first coil and the second coil;
The reactor according to any one of claims 1 to 4, wherein the magnetic shielding member is in contact with the chassis.
The first coil is wound around a first winding axis;
The reactor according to any one of claims 1 to 5, wherein the second coil is wound around a second winding axis parallel to the first winding axis.
The first coil and the first coil are arranged such that a portion of the first winding shaft located in the first coil and a portion of the second winding shaft located in the second coil constitute a pair of opposite sides of a rectangle. The reactor according to claim 6, wherein the second coil is disposed.