JP3305997B2 - Magnetically biased induction magnet - Google Patents

Magnetically biased induction magnet

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Publication number
JP3305997B2
JP3305997B2 JP33833097A JP33833097A JP3305997B2 JP 3305997 B2 JP3305997 B2 JP 3305997B2 JP 33833097 A JP33833097 A JP 33833097A JP 33833097 A JP33833097 A JP 33833097A JP 3305997 B2 JP3305997 B2 JP 3305997B2
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JP
Japan
Prior art keywords
core
magnetic
bias
foot
circuit
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
JP33833097A
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Japanese (ja)
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JPH11176644A (en
Inventor
賢 齋藤
Original Assignee
賢 齋藤
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Filing date
Publication date
Application filed by 賢 齋藤 filed Critical 賢 齋藤
Priority to JP33833097A priority Critical patent/JP3305997B2/en
Publication of JPH11176644A publication Critical patent/JPH11176644A/en
Application granted granted Critical
Publication of JP3305997B2 publication Critical patent/JP3305997B2/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an induction electromagnetic device such as a transformer or a choke which has a coil wound around the outer periphery of a core made of a magnetic material and to which an alternating current with a superimposed direct current is applied.

[0002]

2. Description of the Related Art In an induction electromagnetic device such as a transformer or a choke that passes an alternating current with a superimposed direct current, the operating point of the alternating current shifts by the magnetic field generated by the direct current component, and the margin to saturation is reduced. Therefore, if the DC component is large, a gap is provided in the magnetic circuit so that the core used is not magnetically saturated, and the magnetic resistance is increased by increasing the distance,
Means for preventing magnetic saturation are common. However, such a method results in increased reluctance for both DC and AC.

Therefore, in order to suppress the deviation due to direct current,
For example, it is known that a permanent magnet is inserted into a gap in such a direction as to cancel a magnetic field generated by a DC component flowing through a coil, and a DC magnetic bias is applied to a magnetic circuit of the core.

Further, by applying a DC magnetic bias of an appropriate magnitude to the magnetic circuit of the core, as shown in FIG. 6, the BH curve of the core due to the application of AC is substantially centered on the magnetization origin of the core. By forming a closed curve surrounding the origin, the iron loss of the induction magnet is reduced from the iron loss IR2 indicated by oblique lines when no magnetic bias is applied to the iron loss IR1 indicated by oblique lines when added. It is also known to improve the efficiency (Japanese Patent Application No. 5-344433).
No.).

[0005]

However, when a permanent magnet is inserted into the gap, the gap length is very short and the cross-sectional area of the gap is large. In some cases, a large demagnetizing field is generated and a sufficient magnetic bias cannot be obtained.
Further, when the induction magnet is driven, demagnetization may occur due to a demagnetizing field applied between the magnetic poles. In addition, when a high-frequency magnetic field is applied to the gap, the magnetic flux passes through the inside of the permanent magnet, so that an eddy current is generated in the magnet, resulting in eddy current loss and a reduction in efficiency. For this reason, when a permanent magnet is inserted into the gap, it can only be used for an induction magnet that handles a relatively low frequency.

On the other hand, in order to prevent demagnetization of the magnet and reduce iron loss, there has been known a magnetically biased induction magnet as shown in FIG. 7 (Japanese Utility Model Application No. 1-153254). In this induction magnet, a coil 52 is wound around one leg of a core 51, and a gap 53 is provided on the other leg corresponding to the outer leg of the EI core. Instead of inserting a magnetic bias, a permanent magnet 54 is attached across the two ends to apply a magnetic bias. However, in this case, the iron loss can be reduced and the efficiency can be improved. However, since the gap 53 is provided in the foot portion apart from the winding portion of the core 51, the magnetic resistance of the foot portion increases, resulting in leakage flux. However, there is a problem that the size of the circuit 56 becomes large and adversely affects peripheral circuits and devices such as an induction failure. In particular, when used in a high-frequency circuit, the effect becomes large.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems and to provide a magnetically biased induction magnet which can improve the efficiency and reduce induction disturbance even when used in a high-frequency circuit. And

[0008]

In order to achieve the above object, a magnetically biased induction magnet according to claim 1 comprises an E-shaped core and an I-shaped core having a middle foot and outer feet on both sides thereof. A core that forms a magnetic circuit, and a coil that is wound around the outer periphery of the middle foot of the E-shaped core and to which an alternating current with a superimposed DC is applied. An induction electromagnetic device having a gap between cores, comprising: a magnetic bias applying means provided on a side surface of a tip of the midfoot portion to apply a magnetic bias to at least a magnetic circuit of the E-shaped core, wherein the core is The magnetic bias applying means
The path area of the magnetic circuit part where the magnetic bias is not applied.
It has a bulge that increases .

According to the above construction, the magnetic bias applying means provided on the side surface of the tip of the middle foot portion is provided at least with the E bias.
Since the magnetic bias is added to the magnetic circuit of the mold core, the added magnetic bias can reduce the core loss of the magnetic circuit of the E-type core, which occupies most of the magnetic circuit of the core, and improve the efficiency. . In addition, since the gap is provided between the tip of the middle foot of the E-shaped core and the I-shaped core, leakage magnetic flux is reduced, and even when used in high frequency circuits, induction troubles to peripheral circuits and equipment are reduced. it can. further,
Magnetic circuit part where magnetic bias is not applied and iron loss does not decrease
The iron passage area of this area has been increased, reducing iron loss in this area
Can be done.

It is preferable that the magnetic bias applying means is a pair of permanent magnets which are respectively bridged between the side surface of the tip of the middle foot portion and the outer foot portions on both sides. According to this configuration, a magnetic bias is applied to the magnetic circuit of the E-shaped core by the permanent magnets bridged between the side surface of the tip of the middle foot and the outer foot, and the magnetic circuit of the E-shaped core is Iron loss can be reduced.

It is preferable that the magnetic bias applying means is a pair of permanent magnets and a yoke bridged between the opposing side surfaces of the midfoot and the I-shaped core. According to this configuration, the permanent magnet and the yoke bridged between the side surface of the tip of the middle foot portion and the I-shaped core cause the magnetic circuit not only in the E-shaped core but also in a part of the magnetic circuit of the I-shaped core. A bias can be added to further reduce iron loss.

The yoke is preferably made of a material having a high saturation magnetic flux density equal to or higher than that of the magnetic material forming the core. As a result, the cross-sectional area of the yoke can be reduced and the magnetic flux can be efficiently passed through the core, so that the size can be reduced and the space can be saved.

[0013]

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a front view of a transformer which is a kind of magnetically biased induction magnet according to the first embodiment of the present invention.

The transformer 1 includes an E-type core 3 and an I-type core 4 having a middle foot portion 6 and outer foot portions 8 on both sides thereof, and includes an EI type core 2 forming a magnetic circuit MC. I have. This magnetic circuit MC is a magnetic circuit MC in the E-type core 3.
1 and a magnetic circuit MC2 in the I-type core 4. Also,
The coil 5 to which the alternating current on which the direct current is superimposed is applied
It is located in rectangular windows 7, 7 surrounded by the middle and outer legs 8, 8 of the mold core 3 and the I-shaped core 4, and is wound around the outer periphery of the middle foot 6.

The transformer 1 has a middle foot portion 6 of the E-shaped core.
A gap 10 is provided between the tip 6a of the core 2 and the I-type core 4 to shift the magnetic saturation of the magnetic circuit MC of the core 2 to the high magnetic field side. The I-shaped core 4 has a shape in which a core-added portion (bulging portion) 4a having a predetermined height is integrally formed and stacked on an upper portion, and the overall height of the I-shaped core 4 is increased. The passage area of the magnetic circuit MC2 of the I-type core 4 is increased.

The E-shaped core 3 is disposed in the transformer 1 so as to be in contact with the left and right sides of the tip 6a of the midfoot 6.
A magnetic bias applying means 12 such as a pair of permanent magnets for applying a magnetic bias to the magnetic circuit MC1 is provided. The permanent magnet 12 is made of, for example, a ferrite magnet.

The permanent magnets 12 are located below the gap 10 and in the upper portions of the windows 7, 7, so that the right and left sides of the tip 6 a of the middle foot 6 and the outer feet 8, 8 on both sides are located. Both ends (N-pole, S-pole) are fixed to the respective side surfaces by, for example, bonding. In this way, the magnetic lines of force created by the permanent magnet 12 emerge from the N pole,
A magnetic bias circuit MB1 that returns to the S pole through the middle foot portion 6 and the outer foot portions 8, 8 of the E-shaped core 3 is formed. The magnetic bias circuit MB1 cancels the magnetic field generated by the DC component flowing through the coil 5, that is, generates a bias magnetic field in the direction opposite to the magnetic field of the magnetic circuit MC, and causes the magnetic circuit MC1 of the E-type core 3 to perform the DC magnetic field. Apply a bias.

In the above configuration, the magnetic circuit MC of the E-type core 3 occupying about 80% of the magnetic circuit MC of the core 2 is provided by the magnetic bias circuit MB1 formed by the permanent magnet 12.
1 is subjected to a DC magnetic bias. With the added DC magnetic bias, the magnetic flux density in the E-shaped core 3 can be reduced, and the iron loss can be reduced to improve the efficiency. With respect to the magnetic circuit MC2 of the I-type core 4 to which no magnetic bias is applied, the overall height of the I-type core 4 is increased by the core addition part 4a to increase the passage area of this part, so that the magnetic flux density decreases. I type core 4
Iron loss is reduced. Therefore, the core loss of the entire core 2 is reduced, which is equivalent to applying a magnetic bias to almost the entire area of the core 2, and the efficiency of the entire transformer can be improved.

Further, since the permanent magnet 12 has an elongated shape with a large distance between magnetic poles, unlike a conventional case where a permanent magnet is inserted into the short gap 10, demagnetization due to a demagnetizing field can be eliminated. . In addition, gap 1
Since 0 is provided between the tip 6a of the middle foot portion of the E-shaped core and the I-shaped core 4, a small amount of magnetic flux passes through the permanent magnet, so that the eddy current loss in the permanent magnet is small. Moreover, since the gap structure between the middle foot portion 6 and the I-shaped core 4 does not change in the EI-type core 2, even when used at a high frequency, leakage flux is small, and induction failure and the like can be reduced.

Next, a second embodiment will be described. FIG.
FIG. 7 shows a front view of a magnetically biased transformer according to the second embodiment. Magnetic bias applying means 1 of this transformer
Reference numeral 6 includes a pair of permanent magnets 12 and a yoke 14 which are respectively bridged between left and right side surfaces of the front end 6a of the middle foot portion 6 facing each other and a bottom surface (a lower surface in FIG. 2) of the I-shaped core 4. .
That is, the rear end (S pole) of the permanent magnet 12 and the front end of the yoke 14 standing upright are fixed, for example, by bonding, and the front end (N pole) of the permanent magnet 12 is fixed to the front end 6 of the midfoot 6.
a, and the rear end of the yoke 14 is fixed to the bottom surface of the I-shaped core 4. In this way, the magnetic lines of force generated by the permanent magnets 12 come out of the N pole, and the E-shaped core 3 has the middle foot 6, the outer foot 8,
A magnetic bias circuit MB2 is formed that returns to the south pole through the part of the I-type core 4 and 8. The magnetic bias circuit MB2 generates a bias magnetic field in the opposite direction to the magnetic field of the magnetic circuit MC to generate one of the magnetic circuit MC1 in the E-type core 3 and the magnetic circuit MC2 in the I-type core 4, as described above. DC bias to the part.

The area A1 at the center of the I-type core 4
Does not receive a magnetic bias. The permanent magnet 12 and the yoke 14 are made of, for example, a ferrite magnet. Preferably, the yoke 14 is formed of a material having a high saturation magnetic flux density, such as iron. In this case, by increasing the magnetic flux density passing through the yoke 14, a necessary amount of magnetic flux can be effectively transmitted with a small amount of material, so that the size can be reduced and the space can be saved.

The I-type core 4 includes a magnetic circuit MC2
Of the non-bias area A1 to which the magnetic bias is not applied by the magnetic bias circuit MB2, the I-type core 4 in which the core addition portion (bulging portion) 4b of a predetermined height is added at the upper center thereof is used. Passage area is increased.

Thus, the magnetic circuit MC1 of the E-type core 3
And a magnetic bias circuit MB2 for applying a bias magnetic field in the opposite direction to a part of the magnetic circuit MC2 of the I-type core 4, so that the region to which a magnetic bias is applied is limited by the amount within the I-type core 4 compared to the first embodiment. As a result, a magnetic bias is applied to about 90% of the magnetic circuit MC of the core 2. With the added DC magnetic bias, iron loss of the magnetic circuit MC of the core 2 can be reduced and efficiency can be improved. In the non-biased area A1 of the I-type core 4 to which no magnetic bias is applied, since the passage area of this portion is increased, the core loss is reduced, and the core loss of the entire core 2 can be reduced. Also, since the gap 10 is provided between the tip 6a of the middle foot of the E-shaped core and the I-shaped core 4,
Leakage magnetic flux is small, and even if it is used for a high-frequency circuit, it is possible to reduce disturbances to the peripheral devices.

It is to be noted that, instead of increasing the height of the I-type core 4 at the central portion, as shown in a plan view of FIG. May be increased. In this case, when the coil 5 is wound around the E-shaped core 3, the E-shaped core 3
The thickness direction t is a dead space, so that the use of the I-type core 24 having a widened central portion has little effect. In order to reduce iron loss, the transformer 1 can be reduced in size without increasing the height. Can be planned. In addition, this I-type core 2
4 is a portion of the E-shaped core 3 facing the middle foot portion is expanded,
Leakage flux can also be reduced.

Next, a third embodiment will be described. FIG.
FIG. 7 shows a front view of a magnetically biased transformer according to the third embodiment. Magnetic bias applying means 1 of this transformer
Numeral 8 includes a pair of permanent magnets 12 and a yoke 15 which are respectively bridged between the left and right side surfaces of the tip 6a of the middle foot portion 6 facing each other and the bottom surface of the I-shaped core 4 (the lower surface in FIG. 3). .
Except that the yoke 15 is formed in an L-shape,
This is the same as the embodiment. In this case, the rear end of the L-shaped yoke 14 fixed to the I-shaped core 4 is close to the vicinity of the area where the I-shaped core 4 faces the midfoot 6 with the gap 10 interposed therebetween. . Therefore, since the magnetic bias circuit MB3 extends longer toward the center of the I-type core 4 as compared with the magnetic bias circuit MB2 in FIG. 2, the region to which the magnetic bias is applied is expanded, that is, the magnetic bias is not applied. The bias-free area A2 at the center of the mold core 4 is narrower than the bias-free area A1 in FIG. 2, and a magnetic bias is applied to about 95% of the magnetic circuit MC of the core 2. However, the fixed portion between the rear end of the yoke 14 and the I-shaped core 4 is located outside the area where the I-shaped core 4 faces the midfoot 6 with the gap 10 interposed therebetween in order to maintain the effect of the gap 10. Is provided.

In the same manner as in the second embodiment, the I-type core 4 is provided with a core addition portion (having a predetermined height) in the non-biased area A2 of the magnetic circuit MC2 to which no magnetic bias is applied by the magnetic bias circuit MB3. Bulge 4c
By using the I-shaped core 4 which is added to the center upper portion, the passage area of this portion is increased. As described above, since the non-biased area A2 is smaller than the non-biased area A1 in FIG. 2, a smaller core addition portion 4c can be used as compared with the second embodiment, and the I-type core 4 can be formed smaller. Can be.

Next, a fourth embodiment will be described. FIG. 5 shows a magnetically biased transformer according to the fourth embodiment. FIG. 5A is a front view showing the transformer, and FIG.
5B is a plan view thereof, and FIG. 5C is a longitudinal sectional view taken along line VV of FIG. As shown in FIG. 5B, the central portion of the I-shaped core 24 of the transformer is widened, and as shown in FIG. 6a and I-shaped core 2
4 is provided with a pair of permanent magnets 32 and a yoke 34 which are respectively bridged between the front and rear side surfaces. That is, unlike the first to third embodiments, the magnetic bias applying means 20 of this embodiment is not provided in the windows 7, 7 (FIG. 5A), and the permanent magnet 32 is It is located below the widened portion (bulging portion) of the I-shaped core 24 and below the gap 10, and its tip is fixed to the front and rear side surfaces of the tip 6 a of the midfoot 6, and the upright yoke 34 is an I-shaped core 2
4 is fixed to the side surface of the widened portion. As shown in FIG. 5A, the magnetic bias applying means 20 causes the magnetic bias circuit M excluding the central portion of the I-type core 24 (FIG.
B4 is formed. The central portion of the I-shaped core 24 to which the magnetic bias is not applied is widened and the passage area of this portion is increased, so that the iron loss is reduced.

As described above, the magnetic bias applying means 20 and the widened portion of the I-type core 24 increase the passage area of the portion to which the magnetic bias is not applied and reduce the core loss of the magnetic circuit MC of the core 42 in the same manner as described above. Can be done.

The present invention can be applied not only to the above high frequency transformer but also to a high frequency choke.

[0031]

According to the present invention, the magnetic bias applying means provided on the side surface of the tip of the middle foot part has at least the E bias.
Since the magnetic bias is added to the magnetic circuit of the mold core, the added magnetic bias can reduce the core loss of the magnetic circuit of the E-type core, which occupies most of the magnetic circuit of the core, and improve the efficiency. . In addition, since the gap is provided between the tip of the middle foot of the E-shaped core and the I-shaped core, leakage magnetic flux is reduced, and even when used in high frequency circuits, induction troubles to peripheral circuits and equipment are reduced. it can. further,
Magnetic circuit part where magnetic bias is not applied and iron loss does not decrease
The iron passage area of this area has been increased, reducing iron loss in this area
Can be done.

[Brief description of the drawings]

FIG. 1 is a front view showing a magnetically biased induction magnet according to a first embodiment of the present invention.

FIG. 2 is a front view showing a magnetically biased induction magnet according to a second embodiment.

FIG. 3 is a front view showing a magnetically biased induction magnet according to a third embodiment.

FIG. 4 is a plan view showing an I-shaped core whose central part is widened.

5A is a front view showing a magnetically biased induction magnet according to a fourth embodiment, FIG. 5B is a plan view thereof,
(C) is a longitudinal side view along the VV line of (a).

FIG. 6 is a characteristic diagram showing a BH curve when a magnetic bias is applied.

FIG. 7 is a front view showing a conventional magnetically biased induction magnet.

[Explanation of symbols]

2 core, 3 core E, 4 core I, 5 coil
6: middle foot, 8: outer foot, 10: gap, 12: magnetic bias applying means (permanent magnet).

────────────────────────────────────────────────── ─── Continued on the front page (58) Field surveyed (Int. Cl. 7 , DB name) H01F 17/00-17/08 H01F 19/00-19/08 H01F 27/24-27/26 H01F 30 / 00-30/16

Claims (1)

(57) [Claims]
1. An E-shape having a middle foot portion and outer foot portions on both sides thereof.
A core comprising a core and an I-shaped core, forming a magnetic circuit
Is wound around the outer periphery of the middle foot of the E-shaped core,
A coil to which a superimposed alternating current is applied;
Induction magnet with a gap between the tip of the part and the I-shaped core
There is provided on the side surface of the tip of the midfoot portion, at least the
A magnetic bias for applying a magnetic bias to the magnetic circuit of the E-shaped core
Comprising a Ass adding means, the I-type core, induction electromagnetic device that is magnetically biased and has a bulging portion to increase the passage area of the magnetic circuit portion not applied with the magnetic bias by the magnetic bias adding means.
JP33833097A 1997-12-09 1997-12-09 Magnetically biased induction magnet Expired - Fee Related JP3305997B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP33833097A JP3305997B2 (en) 1997-12-09 1997-12-09 Magnetically biased induction magnet

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP33833097A JP3305997B2 (en) 1997-12-09 1997-12-09 Magnetically biased induction magnet

Publications (2)

Publication Number Publication Date
JPH11176644A JPH11176644A (en) 1999-07-02
JP3305997B2 true JP3305997B2 (en) 2002-07-24

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
JP33833097A Expired - Fee Related JP3305997B2 (en) 1997-12-09 1997-12-09 Magnetically biased induction magnet

Country Status (1)

Country Link
JP (1) JP3305997B2 (en)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6778056B2 (en) * 2000-08-04 2004-08-17 Nec Tokin Corporation Inductance component having a permanent magnet in the vicinity of a magnetic gap
BRPI0617853A2 (en) * 2005-10-25 2011-08-09 Ematech Inc actuator using electromagnetic force and circuit breaker
JP5434505B2 (en) * 2009-11-16 2014-03-05 Fdk株式会社 inductor
JP5809199B2 (en) * 2012-10-16 2015-11-10 Tdk株式会社 pulse transformer

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