The present invention relates to a reactor, a passive element utilizing an inductance.
PTL1 discloses a reactor in which the cross-sectional area of a part of a core around which a coil is wound is larger than the cross-sectional area of a part of the core where the coil is not wound for the purpose of providing the reactor with a small size and improving a DC superposition characteristic for a large current flowing to the reactor.
PTL2 discloses a reactor in which the length of a core where a coil is not wound can be changed for the purpose of making inductance adjustable with a simple structure.
PTL3 discloses a reactor in which the ratio of a length of a part of a core around which a coil is wound to the length of a part of the core where the coils not wound is determined for the purpose of balanced installation and facilitating assembly.
PTL1: Japanese Patent Laid-Open Publication No. 2007-243136
PTL2: Japanese Patent Laid-Open Publication No. 11-23826
PTL3: Japanese Patent Laid-Open Publication No. 2009-259971
A reactor includes a core made of magnetic material and a coil wound around a part of the core. The core includes a first core part having both ends opposite to each other, a second core part having both ends opposite to each other, a third core part having both ends opposite to each other, and a fourth core part having both ends opposite to each other. One end of the both ends of the first core part is connected to one end of the both ends of the third core part. Another end of the both ends of the third core part is connected to one end of the both ends of the second core part. Another end of the both ends of the second core part is connected to one end of the both ends of the fourth core part. Another end of the both ends of the fourth core part is connected to another end of the both ends of the first core part. The coil includes a first coil part wound around a part of the first core part, and a second coil part wound around a part of the second core part. The first core part includes a first winding part around which the first coil part is wound, a first region extending from the one end of the both ends of the first core part to the first winding part, and a second region extending from the another end of the both ends of the first core part to the first winding part. The first coil part is not wound around the first region. The first coil part is not wound around the second region. The second core part includes a second winding part around which the second coil part is wound, a third region extending from the one end of the both ends of the second core part to the second winding part, and a fourth region extending from the another end of the both ends of the second core part to the second winding part. The second coil part is not wound around the third region. The second coil part is not wound around the fourth region. The third core part, the first region of the first core part, and the third region of the second core part constitute a first non-winding part. The fourth core part, the second region of the first core part, and the fourth region of the second core part constitute a second non-winding part. A cross-sectional area S1 of the first core part perpendicular to a direction of a magnetic flux passing through the first core part, a cross-sectional area S2 of the second core part perpendicular to a direction of a magnetic flux passing through the second core part, a cross-sectional area S3 of the third core part perpendicular to a direction of a magnetic flux passing through the third core part, a cross-sectional area S4 of the fourth core part perpendicular to a direction of a magnetic flux passing through the fourth core part, a length A1 of the first winding part, a length A2 of the second winding part, a length B1 of the first non-winding part, and a length B2 of the second non-winding part satisfy following relations: A1+A2<B1+B2; S1>S3; S1>S4; S2>S3; and S2>S4.
This reactor reduces influence of heat and has a small size.
Reactor 10 includes core 20 and coil 30.
Core 20 is made of magnetic material. Core 20 includes core part 21, core part 22, core part 23, and core part 24. Core part 21 is connected to core part 23. Core part 23 is connected to core part 22. Core part 22 is connected to core part 24. Core part 24 is connected to core part 21. Core parts 21, 22, 23, and 24 are all made of the magnetic material. Core 20 has a rectangular annular shape. Reactor 10 has a smaller size than a reactor including a core, such as an EI type core, having another shape.
Core part 21 has both ends 21a and 21b opposite to each other. Core part 22 has both ends 22a and 22b opposite to each other. Core part 23 has both ends 23a and 23b opposite to each other. Core part 24 has both ends 24a and 24b opposite to each other. One end 21a of both ends 21a and 21b of core part 21 is connected to one end 23b of both ends 23a and 23b of core part 23. Another end 23b of both ends 23a and 23b of core part 23 is connected to one end 22a of both ends 22a and 22b of core part 22. Another end 22b of both ends 22a and 22b of core part 22 is connected to one end 24a of both ends 24a and 24b of core part 24. Another end 24b of both ends 24a and 24b of core part 24 is connected to another end 21b of both ends 21a and 21b of core part 21.
Coil 30 is made of a conductor. Coil 30 is wound around core 20. Coil 30 includes coil part 31 and coil part 32. Coil part 31 is electrically connected to coil part 32. Coil part 31 is wound around a part of core part 21. Coil part 32 is wound around a part of core part 22. In accordance with Embodiment 1, coil 30 is made of a copper wire having a rectangular cross section, but may not necessarily have such a cross section.
In
As shown in
Core part 21 includes winding part 25 around which coil part 31 is wound, region 61a extending from one end 21a of core part 21 to winding part 25, and region 61b extending from another end 21b of core part 21 to winding part 25. Coil part 31 is not wound around any of regions 61a and 61b. Core part 22 includes winding part 26 around which coil part 32 is wound, region 62a extending from one end 22a of coil part 22 to winding part 26, and region 62b extending from another end 22b of core part 22 to winding part 26. Coil part 32 is not wound around any of regions 62a and 62b. Core part 23, region 61a of core part 21, and region 62a of core part 22 constitute non-winding part 27. Core part 24, region 61b of core part 21, and region 62b of core part 22 constitute non-winding part 28.
Core 20 has an annular shape. In accordance with Embodiment 1, core 20 has a rectangular annular shape. Winding part 26 is located away from winding part 25 along the annular shape. Non-winding part 27 extends from winding part 25 to winding part 26 along the annular shape. Non-winding part 28 extends from winding part 25 to winding part 26 along the annular shape, and is located opposite to non-winding part 27 with respect to winding parts 25 and 26.
Winding part 25 has length A1 in a direction of magnetic flux M3 passing through winding part 25. Winding part 26 has length A2 in a direction of magnetic flux M3 passing through winding part 26. Non-winding part 27 has length B1 along magnetic flux M3 that passes through non-winding part 27. Non-winding part 28 has length B2 along magnetic flux M3 that passes through non-winding part 28. In the embodiment, winding part 25 is located at the center of core part 21 in the length direction, and winding part 26 is at the center of core part 22 in the length direction. Accordingly, the following relations are satisfied.
B
1
=L
3+(L1−A1)/2+(L2−A2)/2
B
2
=L
4+(L1−A1)/2+(L2−A2)/2
Since L1=L2, L3=L4, and A1=A2 in accordance with the embodiment, the following relation is also satisfied.
B
1
=L
3
+L
1
−A
1
=L
4
+L
2
−A
2
=B
2
The rectangular annular shape of core 20 includes a pair of opposite sides 71 and 72, and a pair of opposite sides 73 and 74. Each of core parts 21 to 24 linearly extends to constitute respective one of four sides 71 to 74 of the rectangular annular shape (see
Reactors have been used in electric circuits to which a large current is applied. Upon having a large current flowing in, the reactor generates large heat. When the reactor generates such large heat, the reactor itself or electronic components disposed around the reactor are thermally affected.
Reactors have been demanded to have small sizes according to a demand to electronic components to have small sizes. However, in view of heat generation, a large reactor is preferable due to heat capacity and heat release area. A simple downsizing of the reactor may result in increasing the temperature of the reactor.
In reactor 10 in accordance with Embodiment 1, both of cross-sectional areas S3 and S4 of core parts 23 and 24 in a direction perpendicular to magnetic flux M3 passing core parts 23 and 24 where coil 30 is not wound are smaller than both of cross-sectional areas S1 and S2 of core parts 21 and 22 in a direction perpendicular to magnetic flux M3 passing core parts 21 and 22 around which coil 30 is wound. More specifically, cross-sectional areas S1, S2, S3, and S4 satisfy relations: S1>S3, S1>S4, S2>S3, and S2>S4 in reactor 10. Even if cross-sectional areas S3 and S4 of core parts 23 and 24 where magnetic flux M3 is relatively small are small, an influence of heat generation is small, hence providing the rector with a small size. The reduction of cross-sectional areas S3 and S4 of core parts 23 and 24 less influence on inductance than the reduction of cross-sectional areas S1 and S2 of core parts 21 and 22 where magnetic flux M3 is relatively large. Reactor 10 thus suppresses the decrease of the inductance.
In reactor 10 in accordance with the embodiment, the sum of lengths A1 and A2 of winding parts 25 and 26 is shorter than the sum of lengths B1 and B2 of non-winding parts 27 and 28. In other words, lengths A1, A2, B1, and B2 satisfy a relation: A1+A2<B1+B2. This relation reduces a loss due to insides of coil parts 31 and 32 being close to each other.
Magnetic flux M3 is larger in winding parts 25 and 26 of core 20 that are regions around which coil parts 31 and 32 are wound than other regions. However, in reactor 10, a distance between regions with large dimensional change is small to reduce a dimensional change due to magnetostriction. Accordingly, reactor 10 has less vibration and thus less vibration noise.
With respect to circuitry efficiency, the loss of reactor 10 is preferably less than 420 W. When ratio RAB exceeds 0.9, the coil loss becomes large. When ratio RAB is less than 0.5, the coil loss can be suppressed, but a core loss becomes large. In addition, ratio RAB equal to or smaller than 0.3 allows lengths of the winding parts to be extremely short, and prevents the coil from being wound easily. Accordingly, lengths A1, A2, B1, and B2 preferably satisfy the relation: (B1+B2)×0.5<A1+A2<(B1+B2)×0.9
Cross-sectional areas S1, S2, S3, and S4 of core parts 21, 22, 23, and 24 preferably satisfy the following relations.
S
1×0.6<S3<S1;
S
1×0.6<S4<S1;
S
2×0.6<S3<S2; and
S
2×0.6<S4<S2.
Reactor 10 can have a small size without causing magnetic saturation when cross-sectional areas S1, S2, S3, and S4 satisfy the above relations.
In reactor 10 in accordance with the embodiment, length L3 of core part 23 in a direction of magnetic flux M3 passing through core part 23 and length L4 of core part 24 in a direction of magnetic flux M3 passing through core part 24 where coil 30 is not wound may be shorter than any of length L1 of core part 21 in a direction of magnetic flux M3 and length L2 of core part 22 in a direction of magnetic flux M3 where coil 30 is wound. In other words, reactor 10 may satisfy relations: L1>L3; L1>L4; L2>L3; and L2>L4. The above relations of lengths L1, L2, L3, and L4 provide reactor 10 with a small size.
As shown in
(B1+B2)×0.5<A1+A2<(B1+B2)×0.9.
In reactor 10a in accordance with Embodiment 2, gaps 41, 42, and 43 are provided in core part 21 while gaps 51, 52, and 53 are provided in core part 22.
Gaps 41, 42, and 43 are positioned in winding part 25. Gaps 51, 52, and 53 are positioned in winding part 25.
Gaps 41 to 43 divide winding part 25 in a direction of magnetic flux M3 passing through winding part 25. Gaps 41 to 43 are arranged in a direction of magnetic flux M3 passing through winding part 25. Similarly, gaps 51 to 53 divide winding part 26 in a direction of magnetic flux M3 passing through winding part 26. Gaps 51 to 53 are arranged in a direction of magnetic flux M3 passing through winding part 26.
The gaps provided in winding parts 25 and 26 effectively causes a magnetic field applied to core 20 to be smaller than a magnetic field applied to the gaps, compared to the case of providing a gap in a portion of core 20 outside winding parts 25 and 26. This configuration improves a direct-current (DC) superimposition characteristic while allowing the gaps to have small sizes.
A reactor according to the present invention is effectively applicable to passive elements utilizing an inductance.
Number | Date | Country | Kind |
---|---|---|---|
2015-078179 | Apr 2015 | JP | national |
Filing Document | Filing Date | Country | Kind |
---|---|---|---|
PCT/JP2016/001628 | 3/22/2016 | WO | 00 |