Electronic device

Abstract

To provide an electronic device having a magnetic core with reduced iron loss.SOLUTION: The electronic device includes a magnetic core 10 composed of a soft magnetic material, and a bias magnetic field application part 20 for applying a bias magnetic field in a direction perpendicular to the excitation direction of the magnetic core 10. Due to the bias magnetic field of the bias magnetic field application part 20, the excitation direction of the magnetic core 10 becomes the magnetization hard axis direction, the B-H curve changes, and the hysteresis loss becomes zero. In addition, in the electronic device, since the excitation direction of the magnetic core 10 is the magnetization hard axis direction, the domain wall motion of the magnetic core 10 due to an external magnetic field different from the bias magnetic field does not occur, and the eddy current loss caused by the domain wall motion becomes zero.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to an electronic device that includes a magnetic core and a mechanism for applying a bias magnetic field perpendicular to the magnetic excitation direction of the magnetic core. [Background technology]

[0002] In recent years, the development of power semiconductor elements using SiC (silicon carbide), GaN (gallium nitride), etc. has led to the development of high-frequency drive in electronic devices such as power converters. This type of electronic device has a magnetic core made of a soft magnetic material and a coil wound around the magnetic core, and from the perspective of high efficiency in high-frequency drive, low iron loss in the magnetic core is required.

[0003] A magnetic core with reduced iron loss has been proposed, for example, as described in Patent Document 1. The magnetic core described in Patent Document 1 is composed of a soft magnetic material containing at least one magnetic metal selected from Fe (iron), Co (cobalt), and Ni (nickel), and having metal grains with magnetic anisotropy in one direction within oriented flat surfaces, and an intervening phase interposed between the metal grains. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6585011 Summary of the Invention [Problem to be solved by the invention]

[0005] In addition to the above, other methods for reducing iron loss in magnetic cores include, for example, controlling the composition and structure of the magnetic material. However, the control of the composition of the magnetic core and magnetic material described in Patent Document 1 is insufficient in reducing iron loss, and there is still room for improvement.

[0006] In view of the above, an object of the present disclosure is to provide an electronic device in which iron loss in a magnetic core is reduced. [Means for solving the problem]

[0007] According to one aspect of the present disclosure, an electronic device includes a magnetic core (10) made of a soft magnetic material and a bias magnetic field application unit (20) that applies a bias magnetic field in a direction (D1, D3) perpendicular to the excitation direction (De) of the magnetic core.

[0008] In this electronic device, a bias magnetic field is applied perpendicular to the excitation direction of the magnetic core, which causes the excitation direction to coincide with the hard-magnetization axis, changing the BH curve so that the coercive force becomes zero, resulting in zero hysteresis loss.In addition, in this electronic device, because the excitation direction coincides with the hard-magnetization axis, domain wall movement in the magnetic core due to the application of an external magnetic field does not occur, and eddy current loss caused by domain wall movement becomes zero, resulting in low iron loss in the magnetic core.

[0009] The reference symbols in parentheses attached to each component indicate an example of the correspondence between the component and the specific components described in the embodiments described below. [Brief explanation of the drawings]

[0010] [Figure 1] 2 is an exploded perspective view showing a magnetic core and a bias magnetic field application unit of the electronic device according to the first embodiment. FIG. [Figure 2] 4 is an explanatory diagram illustrating the relationship between the excitation direction of the magnetic core and the application direction of a bias magnetic field. FIG. [Figure 3] FIG. 10 is an explanatory diagram of the change in the BH curve of the magnetic core depending on whether or not a bias magnetic field is present. [Figure 4] FIG. 10 is a diagram showing the measurement results of the BH curve of a magnetic core with and without a bias magnetic field. [Figure 5] FIG. 5 is an enlarged view showing an enlarged V region of FIG. [Figure 6] FIG. 10 is a diagram showing the relationship between the excitation frequency and iron loss with and without a bias magnetic field. [Figure 7] FIG. 10 is a diagram showing a modified example of the bias magnetic field application unit in the first embodiment. [Figure 8]FIG. 10 is a perspective view showing a magnetic core and a bias magnetic field application unit according to a second embodiment. [Figure 9] FIG. 11 is a perspective view showing a first modified example of the bias magnetic field application unit in the second embodiment. [Figure 10] 10 is a cross section taken along line XX in FIG. 9, showing the relationship between the excitation direction of the magnetic core and the direction in which a bias magnetic field is applied. FIG. [Figure 11] FIG. 10 is a perspective view showing a second modified example of the bias magnetic field application unit in the second embodiment. [Figure 12] 12 is a cross section taken along line XII-XII in FIG. 11, showing the relationship between the excitation direction of the magnetic core and the direction of application of a bias magnetic field. FIG. [Figure 13] FIG. 11 is a perspective view showing a third modified example of the bias magnetic field application unit in the second embodiment. [Figure 14] 14 is a cross section taken along line XIV-XIV in FIG. 13, showing the relationship between the excitation direction of the magnetic core and the direction of application of a bias magnetic field. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. In the following embodiments, identical or equivalent parts will be denoted by the same reference numerals.

[0012] (First embodiment) An electronic device according to a first embodiment will be described. The electronic device according to the present embodiment is suitable for use in, for example, a power converter that can be driven at an operating frequency in the high frequency band, but is not limited to this application and can also be used for other applications.

[0013] The electronic device of this embodiment includes, for example, as shown in FIG. 1, a magnetic core 10, a bias magnetic field application unit 20 that applies a bias magnetic field to the magnetic core 10 that is different from an external magnetic field not shown, and a coil 30 wound around the magnetic core 10.

[0014] The magnetic core 10 is mainly made of a soft magnetic material and is a cylindrical member, as shown in Fig. 1. The magnetic core 10 has two annular surfaces, designated as the upper surface 10a and the lower surface 10b, on which bias magnetic field application units 20 are attached.

[0015] For ease of explanation, the direction along the axis of the cylindrical shape of magnetic core 10, i.e., the direction connecting upper surface 10a and lower surface 10b, will be referred to as the "thickness direction D1" as shown in FIG. 2. Furthermore, with center C representing the center position of magnetic core 10 as viewed from the thickness direction D1, the circumferential direction and radial direction, whose central axis is a virtual line passing through center C and along thickness direction D1, will be referred to as the "circumferential direction D2" and the "radial direction D3," respectively. Radial direction D3 is a direction extending radially from center C between 0° and 360°, but in FIG. 2, for ease of viewing, one direction of radial direction D3 is indicated by an arrow. Furthermore, in FIG. 1, for ease of viewing, only a portion of coil 30 for exciting magnetic core 10 is shown, and portions of the outer periphery of magnetic core 10 and coil 30 that are not visible due to the angle in FIG. 1 are indicated by dashed lines.

[0016] The magnetic core 10 has an inner circumferential surface 10c, which is the surface of the side surface connecting the upper surface 10a and the lower surface 10b closest to the center in the radial direction D3, and an outer circumferential surface 10d, which is the surface on the outside in the radial direction D3, and a coil 30 is wound around the magnetic core 10 to connect the upper surface 10a, the lower surface 10b, the inner circumferential surface 10c, and the outer circumferential surface 10d. The magnetic core 10 is excited by applying a current to the wound coil 30. The magnetic core 10 has an excitation direction De that is a direction along the center of the winding of the wound coil 30, i.e., a direction along the circumferential direction D2. The magnetic core 10 is also called an iron core, a core, or a magnetic core.

[0017] The magnetic core 10 is made of a soft magnetic material, such as a magnetic metal or magnetic compound containing at least one element selected from Fe, Co, and Ni, or the soft magnetic material coated with an insulating layer or the like. The magnetic core 10 can be, for example, a wound core made by winding a thin ribbon of soft magnetic material, a laminated core made by stacking thin plates of soft magnetic material in one direction, a powder core made by pressure-molding a powder of soft magnetic material, or a sintered core made by sintering a powder of soft magnetic material. The magnetic core 10 can be, for example, a wound NANOMET (registered trademark) ribbon made of an Fe-containing alloy of Fe, Si (silicon), B (boron), P (phosphorus), and Cu (copper), in which α-Fe nanocrystals are densely dispersed. However, the magnetic core 10 is not limited to this.

[0018] In this embodiment, the bias magnetic field application units 20 are magnets, and as shown in FIG. 1, one is attached to each of the upper surface 10a and the lower surface 10b of the magnetic core 10. In this embodiment, as shown in FIG. 2, the bias magnetic field application units 20 apply a bias magnetic field BM perpendicular to the excitation direction De of the magnetic core 10, i.e., along the thickness direction D1. The bias magnetic field application units 20 apply a bias magnetic field BM strong enough to saturate the magnetization of the magnetic core 10 in the direction of application of the bias magnetic field BM, thereby aligning the excitation direction De with the hard axis of magnetization of the magnetic core 10. This changes the BH curve of the magnetic core 10 and suppresses domain wall motion when an external magnetic field is applied to the magnetic core 10 by the coil 30. This reduces hysteresis loss and eddy current loss due to domain wall motion, ultimately reducing iron loss. This will be described in more detail later.

[0019] The bias magnetic field application unit 20 is, for example, a double-sided magnet in which one side in the thickness direction D1 is magnetized as an S pole and the other side is magnetized as an N pole. However, this magnetization state is not limited to this, as long as it generates a bias magnetic field BM along the thickness direction D1. For example, the bias magnetic field application unit 20 may be magnetized in an opposite magnetization state to the S pole and N pole shown in FIG. 1 . Furthermore, the bias magnetic field application unit 20 may be, for example, a single-sided multi-pole magnet in which multiple pairs of N and S poles are magnetized on one side in the thickness direction D1, or a double-sided multi-pole magnet in which multiple poles are magnetized on both sides in the same direction. The bias magnetic field application unit 20 is, for example, an NdFeB magnet, but is not limited thereto and may be other known magnets. As described above, the bias magnetic field application unit 20 is only required to generate a magnetic field strong enough to saturate the magnetization of the magnetic core 10. The material, structure, and magnetization state of the bias magnetic field application unit 20 may be appropriately changed depending on the constituent material and structure of the magnetic core 10. For example, when the bias magnetic field applying unit 20 is a magnet, the surface magnetic flux density of the surface of the magnet facing the magnetic core 10 is B Surface The cross-sectional area of ​​the opposing surface is S Magnet Then, the magnetic flux of the magnet is B Surface ×S Magnet On the other hand, the saturation magnetic flux density of the magnetic core 10 is B S The cross-sectional area of ​​the surface of the magnetic core 10 facing the bias magnetic field application unit 20 (the area of ​​the upper surface 10a or the lower surface 10b in the example of FIG. 1) is S Core In this case, the magnetic flux required to saturate the magnetization of the magnetic core 10 in the direction of application of the bias magnetic field BM is B S ×S Core At this time, the bias magnetic field applying unit 20 is B Surface ×S Magnet >B S ×S Core Furthermore, the magnetic circuit structure of the bias magnetic field application unit 20 may be an open magnetic circuit or a closed magnetic circuit.

[0020] Next, the effect of applying the bias magnetic field BM by the bias magnetic field applying unit 20 will be described.

[0021] For ease of explanation, hereinafter, a configuration having a magnetic core 10 and a coil 30 but not having a bias magnetic field application unit 20 will be referred to as a "configuration without a bias magnetic field," and a configuration having a magnetic core 10, a bias magnetic field application unit 20, and a coil 30 will be referred to as a "configuration with a bias magnetic field."

[0022] In the configuration without a bias magnetic field and the configuration with a bias magnetic field, when an external magnetic field H (unit: A / m) of an AC magnetic field is applied to magnetic core 10 by coil 30, the magnetic flux density B (unit: T) changes in accordance with the strength of external magnetic field H, as shown in Fig. 3, for example. In the configuration without a bias magnetic field, the BH curve of the excitation direction De of magnetic core 10 shows different magnitudes of magnetic flux density B when the strength of external magnetic field H is changed in the positive direction and when it is changed in the negative direction, and forms a hysteresis loop that draws a loop in accordance with the change in external magnetic field H.

[0023] There are two types of iron loss: hysteresis loss and eddy current loss, and hysteresis loss is proportional to the area enclosed by the hysteresis loop in the BH curve and the frequency of the AC magnetic field. In a configuration without a bias magnetic field, the BH curve forms a hysteresis loop as shown in Figure 3, resulting in hysteresis loss. In addition, the external magnetic field H generates eddy currents due to domain wall movement in magnetic core 10, resulting in eddy current loss due to domain wall movement.

[0024] On the other hand, in the configuration with a bias magnetic field, a bias magnetic field BM is applied perpendicular to the excitation direction De of the magnetic core 10. The bias magnetic field BM causes magnetization saturation, so the excitation direction De is aligned with the hard axis of magnetization. As a result, as shown in Figure 3, the coercivity of the BH curve becomes zero, and the change in magnetic flux density B is the same when the strength of the external magnetic field H is changed in the positive direction and when it is changed in the negative direction. Therefore, in the configuration with a bias magnetic field, the area enclosed by the hysteresis loop is zero, i.e., hysteresis loss is zero. Furthermore, in the configuration with a bias magnetic field, the excitation direction De is aligned with the hard axis of magnetization, so no domain wall movement occurs in the magnetic core 10 due to the external magnetic field, and no eddy currents are generated due to domain wall movement. Therefore, in the configuration with a bias magnetic field, hysteresis loss and eddy current loss due to domain wall movement are zero, resulting in low iron loss.

[0025] The inventors prepared a sample with a configuration with a bias magnetic field, using a core wound with a thin ribbon of NANOMET (registered trademark) manufactured by Tohoku Magnet Institute Co., Ltd. as the magnetic core 10 and an NdFeB magnet as the bias magnetic field application unit 20. The configuration with a bias magnetic field has a cylindrical magnetic core 10 wound with a coil 30, and magnetic bias magnetic field application units 20 are attached to the top surface 10a and bottom surface 10b of the magnetic core 10. The inventors also prepared a sample with a configuration without a bias magnetic field, which had the same structure as the configuration with a bias magnetic field except that it did not have the bias magnetic field application unit 20.

[0026] The magnetic properties of both samples with and without a bias magnetic field were evaluated using a BH analyzer (BH1000) manufactured by Denshijiki Kogyo Co., Ltd., and the results shown in Figures 4 and 5 were obtained.

[0027] When an external magnetic field H was applied to the configuration without a bias magnetic field, a BH curve was obtained, depicting a hysteresis loop in which the magnetic flux density B changed in the range of approximately -1 T to 1 T, in the range of -600 A / m to 600 A / m, as shown in Figure 4. As shown in Figure 5, the configuration without a bias magnetic field had a coercive force of approximately 15 A / m, and the area enclosed by the hysteresis loop was larger than that of the configuration with a bias magnetic field.

[0028] On the other hand, as shown in Figures 4 and 5, in the configuration with a bias magnetic field, the change in magnetic flux density B due to the external magnetic field H was smaller than in the configuration without a bias magnetic field, and the magnetic moment at which coercivity = 0 changed due to rotational magnetization, resulting in a BH curve that did not form a loop.

[0029] Furthermore, the relationship between the excitation frequency and iron loss of the above two samples was measured using a BH analyzer (SY-8219) manufactured by Iwasaki Electric Co., Ltd., with an excitation magnetic flux density of 100 mT, and the results shown in Figure 6 were obtained. For the configuration without a bias magnetic field, the iron loss was 71 kW / m at excitation frequencies of 10 kHz, 20 kHz, 50 kHz, and 100 kHz. 3 , 158kW / m 3 , 435kW / m 3 , 968kW / m 3 In contrast, the configuration with a bias magnetic field had iron losses of 36 kW / m at excitation frequencies of 10 kHz, 20 kHz, 50 kHz, and 100 kHz. 3 , 73kW / m 3 , 283kW / m 3 , 847kW / m 3As shown, the configuration with a bias magnetic field had lower iron loss than the configuration without a bias magnetic field at all excitation frequencies. This is thought to be because, in the configuration with a bias magnetic field, the BH curve changes as shown in Figures 4 and 5, the hysteresis loss becomes zero, and the excitation direction De is aligned with the hard-magnetization axis, preventing domain wall motion and eliminating eddy current loss due to domain wall motion. Furthermore, because it is sufficient to apply a bias magnetic field BM that saturates the magnetization in a direction perpendicular to the excitation direction De of magnetic core 10, in principle, there are no restrictions on the soft magnetic material of magnetic core 10, improving the freedom of material selection for magnetic core 10.

[0030] According to this embodiment, an electronic device has a magnetic core 10, a bias magnetic field application unit 20, and a coil 30, and is configured to apply a bias magnetic field BM perpendicular to the excitation direction De of the magnetic core 10 by the coil 30. Application of such a bias magnetic field BM causes the excitation direction De of the magnetic core 10 to coincide with the hard-magnetization axis, changing the BH curve so that the coercivity becomes zero, thereby eliminating hysteresis loss. Furthermore, in this electronic device, because the excitation direction De coincides with the hard-magnetization axis, no domain wall motion occurs in the magnetic core 10 due to the application of an external magnetic field, and eddy current loss caused by domain wall motion becomes zero, thereby achieving the effect of reducing iron loss in the magnetic core 10.

[0031] The electronic device of this embodiment also has the following features. (1) The bias magnetic field applying unit 20 is composed of a magnet. (2) The bias magnetic field applying unit 20 generates a bias magnetic field BM having an intensity that saturates the magnetization of the magnetic core 10 . (3) The magnetization state of the bias magnetic field applying unit 20 is one of double-sided magnetization, double-sided multi-pole magnetization, and single-sided multi-pole magnetization. (4) The magnetic circuit structure of the bias magnetic field applying unit 20 is an open magnetic circuit or a closed magnetic circuit. (5) The magnetic core 10 is made of a soft magnetic material that is a magnetic metal or a magnetic compound containing at least one element selected from Fe, Co, and Ni. (6) The magnetic core 10 is a wound or laminated magnetic core made of a magnetic plate or magnetic strip, or a powder or sintered magnetic core made of magnetic powder.

[0032] (Variation) As shown in FIG. 7, the bias magnetic field application units 20 may be attached to the inner circumferential surface 10c and the outer circumferential surface 10d of the magnetic core 10 instead of the upper surface 10a and the lower surface 10b. In this case, the bias magnetic field application units 20 may each be cylindrical, for example, with a diameter different from that of the magnetic core 10, and magnetized to have pairs of north and south poles along the radial direction D3. The two bias magnetic field application units 20 are magnetized so that the south and north poles are alternately arranged from the outside of the radial direction D3 toward the center C, generating a bias magnetic field BM directed inward in the radial direction D3. In other words, when a bias magnetic field BM is applied to the magnetic core 10 in a direction perpendicular to the excitation direction De, i.e., along the radial direction D3, the excitation direction De is configured to be the hard axis direction.

[0033] This modification also provides an electronic device that achieves the same effects as the first embodiment. While FIG. 7 illustrates an example in which the bias magnetic field application unit 20 is a magnet with one north pole and one south pole magnetized on the inner and outer surfaces in the radial direction D3, this is not limiting. For example, the bias magnetic field application unit 20 may have the south and north poles magnetized in opposite directions in FIG. 7 . Furthermore, the bias magnetic field application unit 20 may be a double-sided or single-sided multipole magnetized magnet with a magnetization direction perpendicular to the inner circumferential surface 10c and the outer circumferential surface 10d, as long as it generates a bias magnetic field BM along the radial direction D3. For clarity, FIG. 7 omits the coil 30 wound around the magnetic core 10. The bias magnetic field application unit 20 is attached to the inner circumferential surface 10c and the outer circumferential surface 10d, for example, so as to sandwich the coil 30 between the magnetic core 10 and the bias magnetic field application unit 20. In this modification, the coil 30 may be wound around the magnetic core 10 and the bias magnetic field application unit 20.

[0034] (Second embodiment) An electronic device according to a second embodiment will now be described.

[0035] The electronic device of this embodiment differs from the first embodiment in that the bias magnetic field application unit 20 is configured with a coil, as shown in Fig. 8, for example. This difference will be mainly described in this embodiment. Note that, for ease of viewing, Fig. 8 omits the coil 30 that is wound around the magnetic core 10 and excites the magnetic core 10. This also applies to Fig. 9 and subsequent figures described below.

[0036] In this embodiment, the bias magnetic field application unit 20 is, for example, a coil having a substantially ring-shaped ring portion 21 and wiring portions 22 extending from one end of the ring portion 21 and the other end on the opposite side, and is disposed so as to surround a portion of the outer circumferential surface 10d of the magnetic core 10. The wiring portion 22 of the bias magnetic field application unit 20 is connected to an external power supply (not shown), and by applying a current, the bias magnetic field application unit 20 generates a bias magnetic field BM in the ring portion 21 along the thickness direction D1 of the magnetic core 10. As a result, similar to the first embodiment, the bias magnetic field BM is applied to the magnetic core 10 by the bias magnetic field application unit 20 configured with a coil along a direction perpendicular to the excitation direction De. As in the first embodiment, a predetermined current is applied to the bias magnetic field application unit 20 so as to generate a bias magnetic field BM of a strength that saturates the magnetization of the magnetic core 10.

[0037] This embodiment also provides an electronic device that can achieve the same effects as the first embodiment.

[0038] (First Modification) The bias magnetic field application unit 20 may be partially disposed inside the magnetic core 10, as shown in FIG. 9 . Specifically, the bias magnetic field application unit 20 includes, for example, a substantially cylindrical portion 23 having a substantially cylindrical shape and a wiring portion 22 extending from the substantially cylindrical portion, with the wiring portion extending from the top surface 10a of the magnetic core 10. Note that in FIG. 9 , the outline of the portion of the substantially cylindrical portion 23 that cannot be seen from the outside is indicated by a dashed line. For example, as shown in FIG. 10 , the bias magnetic field application unit 20 has a substantially cylindrical portion whose height in the thickness direction D1 is approximately the same as that of the magnetic core 10 and is disposed inside the magnetic core 10 in the radial direction D3. As shown in FIG. 10 , the bias magnetic field application unit 20 generates a bias magnetic field BM that rotates around the current in the substantially cylindrical portion by applying a current. In this modification, the bias magnetic field application unit 20 generates a bias magnetic field BM that is perpendicular to the excitation direction De of the substantially cylindrical portion 23, thereby aligning the excitation direction De with the hard axis direction of magnetization of the magnetic core 10.

[0039] This modification also provides an electronic device that can achieve the same effects as the second embodiment.

[0040] (Second Modification) As shown in FIG. 11 , the bias magnetic field application unit 20 may have a ring portion 21 having a substantially ring shape similar to that of the second embodiment, and wiring portions 22 extending from one end and the other end of the ring portion 21, with the ring portion 21 embedded inside the magnetic core 10. Note that in FIG. 11 , dashed lines indicate the portion of the outer periphery of the magnetic core 10 that is not visible at the angle shown in the figure, and the outer periphery of the ring portion 21 that is not directly visible from the outside. In this case, as shown in FIG. 12 , the bias magnetic field application unit 20 generates a bias magnetic field BM that rotates around the ring portion 21 by applying a current. In this modification, the bias magnetic field application unit 20 applies a bias magnetic field BM to the magnetic core 10 along a radial direction D3, with the ring portion 21 being perpendicular to the excitation direction De of the magnetic core 10. Note that Figure 12 shows a representative example in which the bias magnetic field BM generated by the bias magnetic field application unit 20 is configured as a closed magnetic circuit generated only within the magnetic core 10, but this is not limited to this, and the bias magnetic field BM may also be configured as an open magnetic circuit generated outside the magnetic core 10.

[0041] This modification also provides an electronic device that can achieve the same effects as the second embodiment.

[0042] (Third Modification) As shown in FIG. 13 , the bias magnetic field application unit 20 may have an open-ring-shaped, approximately circular portion 24 and wiring portions 22 extending from one end of the approximately circular portion 24 and the other end on the opposite side, with the approximately circular portion 24 embedded inside the magnetic core 10. In FIG. 13 , the outline of the approximately circular portion 24, which cannot be directly seen from the outside, is indicated by a dashed line. In this modification, as shown in FIG. 14 , the approximately circular portion 24 is disposed near the center of the magnetic core 10 in the thickness direction D1, and is exposed on the inner circumferential surface 10 c and the outer circumferential surface 10 d of the magnetic core 10. When a current is applied, the bias magnetic field application unit 20 generates a bias magnetic field BM that rotates around the approximately circular portion 24 and applies the bias magnetic field BM along the radial direction D3 to the magnetic core 10.

[0043] This modification also provides an electronic device that can achieve the same effects as the second embodiment.

[0044] (Other embodiments) Although the present disclosure has been described with reference to the embodiments, it is understood that the present disclosure is not limited to the embodiments or structures. The present disclosure also encompasses various modifications and modifications within the scope of equivalents. In addition, various combinations and forms, as well as other combinations and forms including only one element, more than one, or less than one, are also within the scope and spirit of the present disclosure.

[0045] For example, in the modified example of the second embodiment, a case where a counterclockwise bias magnetic field BM is generated around the axis of the coil due to the current in the bias magnetic field application unit 20 formed as a coil has been described as a representative example, but the present invention is not limited to this. For example, even if the current in the bias magnetic field application unit 20 formed as a coil is reversed to generate a clockwise bias magnetic field BM around the coil, the bias magnetic field BM is applied perpendicular to the excitation direction De of the magnetic core 10. Therefore, when the bias magnetic field application unit 20 is formed as a coil, the direction of the current in the coil is not particularly limited. This is also true for the second embodiment.

[0046] It goes without saying that in each of the above embodiments, the elements constituting the embodiments are not necessarily essential unless they are specifically stated as essential or are clearly considered essential in principle. Furthermore, in each of the above embodiments, when numerical values ​​such as the number, values, amounts, and ranges of the components of the embodiments are mentioned, they are not limited to the specific numbers unless they are specifically stated as essential or are clearly limited to a specific number in principle. Furthermore, in each of the above embodiments, when the shapes, positional relationships, etc. of the components are mentioned, they are not limited to the shapes, positional relationships, etc., unless they are specifically stated or are clearly limited to a specific shape, positional relationship, etc. in principle.

[0047] (Aspects of the present disclosure) The present disclosure described above can be understood from the following viewpoints, for example. [First viewpoint] a magnetic core (10) made of a soft magnetic material; and a bias magnetic field application unit (20) that applies a bias magnetic field in a direction (D1, D3) perpendicular to the excitation direction (De) of the magnetic core. [Second viewpoint] The electronic device according to the first aspect, wherein the bias magnetic field application unit is a magnet. [Third Perspective] The electronic device according to the first or second aspect, wherein the bias magnetic field application section generates the bias magnetic field of an intensity that saturates the magnetization of the magnetic core. [Fourth viewpoint] The electronic device according to the second or third aspect, wherein the magnetization state of the bias magnetic field application unit is one of double-sided magnetization, double-sided multi-pole magnetization, and single-sided multi-pole magnetization. [Fifth viewpoint] The electronic device according to any one of the second to fourth aspects, wherein the magnetic circuit structure of the bias magnetic field application unit is an open magnetic circuit or a closed magnetic circuit. [Sixth viewpoint] The electronic device according to any one of the first to fifth aspects, wherein the soft magnetic material is a magnetic metal or a magnetic compound containing at least one element selected from Fe, Co, and Ni. [Seventh viewpoint] The electronic device according to any one of the first to sixth aspects, wherein the magnetic core is a wound magnetic core or a laminated magnetic core made of a magnetic plate or a magnetic strip. [Eighth viewpoint] The electronic device according to any one of the first to sixth aspects, wherein the magnetic core is a powder magnetic core or a sintered magnetic core made of magnetic powder. [Explanation of symbols]

[0048] 10 magnetic core 20 Bias magnetic field application unit D1 Thickness direction of magnetic core D3 Radial direction of the magnetic core De: Excitation direction of the magnetic core

Claims

1. a magnetic core (10) made of a soft magnetic material; and a bias magnetic field applying unit (20) that applies a bias magnetic field in a direction perpendicular to the excitation direction of the magnetic core.

2. The electronic device according to claim 1 , wherein the bias magnetic field applying unit is a magnet.

3. The electronic device according to claim 2 , wherein the bias magnetic field applying section generates the bias magnetic field having an intensity that saturates the magnetization of the magnetic core.

4. 3. The electronic device according to claim 2, wherein the bias magnetic field applying unit has a magnetized state selected from the group consisting of double-sided magnetization, double-sided multi-pole magnetization, and single-sided multi-pole magnetization.

5. 3. The electronic device according to claim 2, wherein the magnetic circuit structure of the bias magnetic field applying unit is an open magnetic circuit or a closed magnetic circuit.

6. 2. The electronic device according to claim 1, wherein the soft magnetic material is a magnetic metal or a magnetic compound containing at least one element selected from the group consisting of Fe, Co, and Ni.

7. 7. The electronic device according to claim 1, wherein the magnetic core is a wound magnetic core or a laminated magnetic core made of a magnetic plate or a magnetic strip.

8. 7. The electronic device according to claim 1, wherein the magnetic core is a powder magnetic core or a sintered magnetic core made of magnetic powder.

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