Reactor, converter, and power conversion device

Abstract

To provide a reactor capable of reducing influences of leakage magnetic flux upon a sensor.SOLUTION: The present invention relates to a reactor comprising a reactor including a coil and a magnetic core and a sensor for measuring a physical quantity of the reactor. The coil includes a cylindrical winding part and the magnetic core includes: a first end core part and a second end core part; a middle core part; and a first side core part and a second side core part. The middle core part includes a portion disposed inside of the winding part. The first side core part and the second side core part are disposed in parallel outside of the winding part so as to hold the middle core part therebetween. The middle core part, the first side core part and the second side core part connect the first end core part and the second end core part. Relative magnetic permeability of the second end core part is greater than relative magnetic permeability of the first end core part, and the sensor is disposed closer to the second end core part than a centerline between the first end core part and the second end core part.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a reactor, a converter, and a power conversion device. [Background technology]

[0002] A reactor is one of the components of a converter mounted on a vehicle such as a hybrid car. Patent Documents 1 and 2 disclose an on-vehicle reactor.

[0003] Patent Document 1 discloses a reactor including a coil and a magnetic core formed by combining two core pieces. The reactor shown in FIG. 1 and FIG. 2 of Patent Document 1 includes a coil having two windings and a magnetic core having two U-shaped core pieces. This magnetic core is a so-called UU-type core. The UU-type core is configured in a ring shape by combining the U-shaped core pieces so that their end faces face each other. The reactor shown in FIG. 5 and FIG. 6 of Patent Document 1 includes a coil having one winding and a magnetic core having two E-shaped core pieces. This magnetic core is a so-called EE-type core. The EE-type core is configured in a θ-shape by combining the E-shaped core pieces so that their end faces face each other.

[0004] Patent Document 2 discloses a reactor equipped with a sensor that measures a physical quantity of the reactor. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2016-201509 A [Patent Document 2] JP 2016-082043 A Summary of the Invention [Problem to be solved by the invention]

[0006] In order to control the reactor according to its state, various sensors that measure the physical quantities of the reactor may be attached to the reactor, such as a current sensor that measures the current flowing through the coil and a temperature sensor that measures the temperature of the coil and the magnetic core.

[0007] The sensor may be affected by magnetic flux leaking from the magnetic core when the reactor is in operation. The effect of the leakage flux from the magnetic core may cause the sensor's operation to become unstable. In such cases, the measurement accuracy of the sensor may deteriorate. Therefore, when placing a sensor in a reactor, it is desirable to suppress the effect of the leakage flux on the sensor.

[0008] An object of the present disclosure is to provide a reactor capable of reducing the effect of leakage magnetic flux on a sensor. Another object of the present disclosure is to provide a converter including the reactor. Still another object of the present disclosure is to provide a power conversion device including the converter. [Means for solving the problem]

[0009] The reactor of the present disclosure includes: A reactor including a coil and a magnetic core; a sensor for measuring a physical quantity of the reactor, The coil has a cylindrical winding portion, The magnetic core has first and second end core portions, a middle core portion, and first and second side core portions, the middle core portion has a portion disposed inside the winding portion, the first side core portion and the second side core portion are arranged side by side on the outside of the winding portion so as to sandwich the middle core portion, the middle core portion, the first side core portion, and the second side core portion connect between the first end core portion and the second end core portion, the second end core portion has a relative permeability greater than the relative permeability of the first end core portion; The sensor is disposed on the second end core portion side of a center line between the first end core portion and the second end core portion.

[0010] The converter of the present disclosure includes the reactor of the present disclosure.

[0011] The power conversion device of the present disclosure includes the converter of the present disclosure. Effect of the Invention

[0012] The reactor according to the present disclosure can reduce the effect of leakage magnetic flux on a sensor, and the converter and power conversion device according to the present disclosure facilitate accurate measurement of a physical quantity of the reactor by a sensor. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a schematic perspective view showing a reactor according to the first embodiment. [Diagram 2] FIG. 2 is a schematic plan view showing the reactor according to the first embodiment. [Diagram 3] FIG. 3 is a schematic front view of the reactor according to the first embodiment as viewed from the second end core portion side. [Figure 4] FIG. 4 is a schematic plan view showing the reactor according to the second embodiment. [Diagram 5] FIG. 5 is a schematic plan view showing a reactor according to the third embodiment. [Figure 6] FIG. 6 is a schematic diagram showing the power supply system of a hybrid vehicle. [Figure 7] FIG. 7 is a circuit diagram showing an outline of an example of a power conversion device including a converter. [Figure 8] FIG. 8 is a diagram showing measurement points in Analysis Example 1 of Test Example 1. [Figure 9] FIG. 9 is a graph showing the change over time in magnetic flux density obtained in Analysis Example 1 of Test Example 1. [Figure 10] FIG. 10 is a diagram showing measurement points in Analysis Example 2 of Test Example 1. [Figure 11] FIG. 11 is a graph showing the change over time in magnetic flux density obtained in analysis example 2 of test example 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] [Description of the embodiments of the present disclosure] The present inventors have made the following findings after extensive research into the influence of leakage flux on sensors. When the inventors investigated the distribution of leakage flux in a magnetic core, they found that the way in which magnetic flux leaks varies depending on the shape of the magnetic core. When the magnetic core is configured in a θ-shape, as in the above-mentioned EE-type, magnetic flux is likely to leak from the end core portion of the magnetic core that is located outside the coil. On the other hand, when the magnetic core is configured in a ring shape, as in the above-mentioned UU-type, magnetic flux is relatively unlikely to leak. Therefore, particularly when a θ-shaped magnetic core is used, it is necessary to take care to minimize the influence of leakage flux on the sensor.

[0015] In order to prevent the sensor from being affected by leakage magnetic flux, for example, it is possible to move the sensor away from the magnetic core or to use a sensor with a magnetic shield. However, when the sensor is moved away from the magnetic core, there are problems such as inaccurate measurement and limitations on the location where the sensor can be placed. In other words, the degree of freedom in the layout of the sensor is reduced. In addition, sensors with magnetic shields are expensive, which leads to a problem of high costs. It is desirable to reduce the effect of leakage magnetic flux on the sensor by a simple means.

[0016] The present disclosure is based on the above findings. First, embodiments of the present disclosure will be listed and described.

[0017] (1) A reactor according to an embodiment of the present disclosure includes: A reactor including a coil and a magnetic core; a sensor for measuring a physical quantity of the reactor, The coil has a cylindrical winding portion, The magnetic core has first and second end core portions, a middle core portion, and first and second side core portions, the middle core portion has a portion disposed inside the winding portion, the first side core portion and the second side core portion are arranged side by side on the outside of the winding portion so as to sandwich the middle core portion, the middle core portion, the first side core portion, and the second side core portion connect between the first end core portion and the second end core portion, the second end core portion has a relative permeability greater than the relative permeability of the first end core portion; The sensor is disposed on the second end core portion side of a center line between the first end core portion and the second end core portion.

[0018] The reactor of the present disclosure can reduce the effect of leakage magnetic flux on the sensor. In the reactor of the present disclosure, the sensor is arranged on the second end core portion side. Since the relative permeability of the second end core portion is greater than the relative permeability of the first end core portion, the magnetic flux leaking from the second end core portion is less than the magnetic flux leaking from the first end core portion. In the reactor of the present disclosure, since the sensor is arranged on the second end core portion side, the effect of leakage magnetic flux on the sensor is smaller than when the sensor is arranged on the first end core portion side. Therefore, since the sensor is less affected by leakage magnetic flux, it is easy to accurately measure the physical quantity of the reactor.

[0019] (2) As one embodiment of a reactor according to the present disclosure, The first end core portion may have a relative magnetic permeability of 5 or more and 50 or less.

[0020] The smaller the relative permeability of the first end core portion, the more the leakage magnetic flux from the first end core portion increases. In the above embodiment, there is a great advantage in arranging the sensor on the second end core portion side.

[0021] (3) As one embodiment of the reactor described in (2) above, The second end core portion may have a relative magnetic permeability of 100 or more and 500 or less.

[0022] The above embodiment can reduce leakage flux from the second end core portion, thereby suppressing the effect of leakage flux on the sensor.

[0023] (4) As one embodiment of a reactor according to the present disclosure, The distance from the second end core portion to the sensor may be within 50 mm.

[0024] In the above embodiment, the distance between the sensor and the second end core portion is short. In the above embodiment, the sensor can be disposed close to the reactor, which increases the degree of freedom in the layout of the sensor.

[0025] (5) As one embodiment of a reactor according to the present disclosure, The sensor may be disposed at a position where a change in density of magnetic flux leaking from the magnetic core is equal to or smaller than 2.0 mT when the reactor is operated under a first operating condition. The first operating condition is an input voltage of 200V, a boosted voltage of 400V, a switching frequency of 20kHz, and a superimposed current of 100A.

[0026] The greater the change in leakage flux, the more the sensor is affected by it. If the sensor is placed in a position where the change in magnetic flux density of the leakage flux is 2.0 mT or less, the sensor is less susceptible to the effects of the leakage flux.

[0027] (6) As one embodiment of the reactor described in (5) above, Furthermore, the maximum value of the magnetic flux density may be 6.0 mT or less.

[0028] The greater the magnetic flux density of the leakage flux, the more susceptible the sensor is to being affected by the leakage flux. If the sensor is placed in a position where the maximum magnetic flux density of the leakage flux is 6.0 mT or less, the sensor is less susceptible to being affected by the leakage flux.

[0029] (7) As one embodiment of the reactor according to (5) or (6), The sensor may be disposed in a region overlapping with the second end core portion when the reactor is viewed in a plan view.

[0030] The above configuration provides a high degree of freedom in terms of sensor layout.

[0031] (8) As one embodiment of the reactor according to any one of (5) to (7) above, When the reactor is viewed from above, the sensor may be disposed in a region on an extension of the middle core portion.

[0032] The above configuration provides a high degree of freedom in terms of sensor layout.

[0033] (9) As one embodiment of a reactor according to the present disclosure, A circuit board for controlling a current flowing through the coil is provided. the sensor is a current sensor; The current sensor may be provided on the circuit board.

[0034] A circuit board that controls the current flowing through the coil may be installed around the reactor. In the above embodiment, the current flowing through the coil can be measured by a current sensor provided on the circuit board.

[0035] (10) As one embodiment of a reactor according to the present disclosure, the sensor is a temperature sensor; The temperature sensor may be fixed to the second end core portion.

[0036] In the above embodiment, the temperature of the second end core portion can be measured by the temperature sensor.

[0037] (11) As one embodiment of a reactor according to the present disclosure, the first end core portion is formed of a molded body of a composite material in which soft magnetic powder is dispersed in a resin, The second end core portion may be formed of a powder compact of raw material powder containing soft magnetic powder.

[0038] Generally, the relative magnetic permeability of a composite material compact is smaller than that of a powder compact. In the above embodiment, the first end core portion is made of a composite material compact and the second end core portion is made of a powder compact, so that the magnetic core can be configured so that the relative magnetic permeability of the second end core portion is greater than that of the first end core portion.

[0039] (12) A converter according to an embodiment of the present disclosure includes: The reactor according to any one of (1) to (11) above is included.

[0040] Since the converter of the present disclosure includes the reactor of the present disclosure, it is easy to accurately measure the physical quantity of the reactor using a sensor.

[0041] (13) A power conversion device according to an embodiment of the present disclosure includes: The converter includes the converter described in (12) above.

[0042] Since the power conversion device of the present disclosure includes the converter of the present disclosure, it is easy to accurately measure the physical quantity of the reactor using a sensor.

[0043] [Details of the embodiment of the present disclosure] Specific examples of the embodiments of the present disclosure will be described below with reference to the drawings. The same reference numerals in the drawings indicate the same objects. Note that the present invention is not limited to these examples, but is indicated by the claims, and is intended to include all modifications within the meaning and scope of the claims.

[0044] [Embodiment 1] [Reactor] A reactor 1a of the first embodiment will be described with reference to Fig. 1 to Fig. 3. The reactor 1a includes a coil 2 and a magnetic core 3. The coil 2 has a winding portion 20. The magnetic core 3 has a first end core portion 35a and a second end core portion 35b. Furthermore, the reactor 1a includes a sensor 6 (see Figs. 2 and 3).

[0045] One of the features of the reactor 1a of the first embodiment is that it satisfies the following requirements (a) and (b). (a) The relative magnetic permeability of the second end core portion 35b is greater than the relative magnetic permeability of the first end core portion 35a. As shown in FIG. 2(b), the sensor 6 is disposed on the second end core portion 35b side of the center line between the first end core portion 35a and the second end core portion 35b. In the reactor 1a, the sensor 6 is disposed on the second end core portion 35b side, and therefore the influence of leakage magnetic flux on the sensor 6 can be reduced compared to a case in which the sensor 6 is disposed on the first end core portion 35a side. The configuration of the reactor 1a will be described in detail below.

[0046] <Coil> As shown in Figs. 1 and 2, the coil 2 has a cylindrical winding portion 20. The winding portion 20 is a portion where the winding is wound in a spiral shape. A known winding can be used for the winding. The winding is a coated rectangular wire having a conductor wire and an insulating coating that covers the conductor wire. The conductor wire is a rectangular wire made of copper. The insulating coating is made of enamel. In this embodiment, the number of winding portions 20 is one. The number of turns of the winding portion 20 is, for example, 10 turns or more and 60 turns or less, and further 20 turns or more and 50 turns or less. In this embodiment, the coil 2 is an edgewise coil formed by edgewise winding a coated rectangular wire.

[0047] The shape of the winding part 20 is tubular. The shape of the winding part 20 may be a polygonal tube or a cylindrical shape. A polygonal tube refers to a shape in which the contour shape of the end face of the winding part 20 as viewed from the axial direction is polygonal. Examples of polygonal shapes include a quadrilateral shape, a hexagonal shape, and an octagonal shape. A quadrilateral shape includes a rectangular shape. A rectangular shape includes a square shape. A cylindrical shape refers to a shape in which the contour shape of the end face is circular. A circular shape includes not only a perfect circular shape but also an elliptical shape. In this embodiment, the shape of the winding part 20 is a rectangular tube.

[0048] The winding portion 20 has a first end face 22a and a second end face 22b. The first end face 22a is an end face on one side in the axial direction of the winding portion 20. The second end face 22b is an end face on the other side in the axial direction of the winding portion 20.

[0049] The coil 2 has a terminal portion 21. The terminal portion 21 is a portion where the winding is pulled out from both ends of the winding portion 20. The terminal portion 21 has a first terminal portion 21a and a second terminal portion 21b. The first terminal portion 21a is pulled out from one end of the winding portion 20 to the outer periphery of the winding portion 20. The second terminal portion 21b is pulled out from the other end of the winding portion 20 to the outer periphery of the winding portion 20. In the first terminal portion 21a and the second terminal portion 21b, the insulating coating is stripped off to expose the conductor wire. For example, a bus bar (not shown) is connected to the first terminal portion 21a and the second terminal portion 21b. The coil 2 is connected to an external device (not shown) via the bus bar. The external device is a power source that supplies power to the coil 2.

[0050] <Magnetic core> As shown in Figs. 1 and 2, the magnetic core 3 has a middle core portion 31, a side core portion 33, and an end core portion 35. The magnetic core 3 is configured to have a θ shape as a whole in a plan view. In this embodiment, the magnetic core 3 includes a first core 3a and a second core 3b. The magnetic core 3 is configured by combining the first core 3a and the second core 3b. The first core 3a and the second core 3b are combined in the axial direction of the winding portion 20. In Fig. 2, the boundary between the middle core portion 31 and the end core portion 35 and the boundary between the side core portion 33 and the end core portion 35 are indicated by two-dot chain lines. The first core 3a and the second core 3b will be described later.

[0051] In the following description, the direction along the axial direction of the winding portion 20 is defined as the X direction. The direction in which the middle core portion 31 and the side core portion 33 are arranged side by side is defined as the Y direction. The Y direction is perpendicular to the X direction. The direction perpendicular to both the X direction and the Y direction is defined as the Z direction. In the Z direction, the side where the terminal portion 21 of the coil 2 is located is defined as the upper side, and the opposite side is defined as the lower side. The plan view mentioned above refers to the state in which the reactor 1a is viewed from above, i.e., the Z direction.

[0052] The magnetic core 3 has a θ-shaped shape when viewed from the Z direction as shown in Fig. 2. When a current is applied to the coil 2, a θ-shaped closed magnetic circuit is formed in the magnetic core 3. This closed magnetic circuit is a closed magnetic circuit in which magnetic flux generated by the coil 2 passes from the middle core portion 31 through one end core portion 35, each side core portion 33, the other end core portion 35, and returns to the middle core portion 31.

[0053] (End core part) The end core portion 35 is a portion disposed on the outside of the winding portion 20. There are two end core portions 35. The end core portions 35 have a first end core portion 35a and a second end core portion 35b. The first end core portion 35a and the second end core portion 35b are disposed at an interval in the X direction. The first end core portion 35a is located on one side in the X direction. The first end core portion 35a faces the first end face 22a of the winding portion 20. The second end core portion 35b is located on the other side in the X direction. The second end core portion 35b faces the second end face 22b of the winding portion 20.

[0054] The shape of each of the first end core portion 35a and the second end core portion 35b is not particularly limited as long as it is a shape that forms a predetermined magnetic path. In this embodiment, each of the first end core portion 35a and the second end core portion 35b is substantially rectangular parallelepiped in shape.

[0055] (Middle core section) The middle core portion 31 has a portion that is disposed inside the winding portion 20. There is one middle core portion 31. The middle core portion 31 is a portion of the magnetic core 3 that is sandwiched between the first end core portion 35a and the second end core portion 35b. The middle core portion 31 extends along the X direction. The axial direction of the middle core portion 31 coincides with the axial direction of the winding portion 20. In this embodiment, both end portions of the middle core portion 31 protrude from both end faces of the winding portion 20. The protruding portions are also part of the middle core portion 31.

[0056] One end of the middle core portion 31 in the X direction is connected to the first end core portion 35a. The other end of the middle core portion 31 in the X direction is connected to the second end core portion 35b.

[0057] The shape of the middle core portion 31 is not particularly limited as long as it corresponds to the inner shape of the winding portion 20. In this embodiment, the shape of the middle core portion 31 is a substantially rectangular parallelepiped. When viewed from the X direction, the corners of the outer circumferential surface of the middle core portion 31 may be rounded to fit the inner circumferential surface of the winding portion 20.

[0058] The middle core portion 31 may or may not be divided in the X direction. In this embodiment, the middle core portion 31 is divided in the X direction and has a first middle core portion 31a and a second middle core portion 31b. The end face of the first middle core portion 31a and the end face of the second middle core portion 31b face each other in the X direction. The first middle core portion 31a is located on one side in the X direction where the first end core portion 35a is arranged. The one side in the X direction is the upper side of the paper in FIG. 2. The end of the first middle core portion 31a is connected to the first end core portion 35a. The second middle core portion 31b is located on the other side in the X direction where the second end core portion 35b is arranged. The other side in the X direction is the lower side of the paper in FIG. 2. The end of the second middle core portion 31b is connected to the second end core portion 35b.

[0059] The length of each of the first middle core portion 31a and the second middle core portion 31b may be set appropriately. The length here refers to the length along the X direction. In this embodiment, the first middle core portion 31a is longer than the second middle core portion 31b. Unlike the embodiment, the first middle core portion 31a may be shorter than the second middle core portion 31b. The first middle core portion 31a and the second middle core portion 31b may have the same length.

[0060] In this embodiment, the middle core part 31 has a gap part 3g. The gap part 3g is provided between the first middle core part 31a and the second middle core part 31b. The gap part 3g is located inside the winding part 20. By the gap part 3g being located inside the winding part 20, the leakage magnetic flux from the gap part 3g is reduced compared to the case where the gap part 3g is located outside the winding part 20. Therefore, the loss caused by the leakage magnetic flux from the gap part 3g can be reduced. The length of the gap part 3g along the X direction may be appropriately set so as to obtain a predetermined inductance. The length of the gap part 3g is, for example, 0.1 mm or more and 2 mm or less, 0.3 mm or more and 1.5 mm or less, or further 0.5 mm or more and 1 mm or less. The gap part 3g may be an air gap. A non-magnetic material such as resin or ceramics may be arranged in the gap part 3g. Unlike this embodiment, the gap part 3g may not be provided. In this case, the end face of the first middle core portion 31a and the end face of the second middle core portion 31b are in contact with each other, and there is substantially no gap between the first middle core portion 31a and the second middle core portion 31b.

[0061] (Side core part) The side core portion 33 is a portion disposed on the outside of the winding portion 20. The number of side core portions 33 is two. The side core portion 33 has a first side core portion 33a and a second side core portion 33b. The first side core portion 33a and the second side core portion 33b are arranged in parallel to sandwich the middle core portion 31. In other words, the middle core portion 31 is disposed between the first side core portion 33a and the second side core portion 33b. Each of the first side core portion 33a and the second side core portion 33b extends in the X direction. The axial direction of each of the first side core portion 33a and the second side core portion 33b is parallel to the axial direction of the middle core portion 31. The first side core portion 33a and the second side core portion 33b are disposed at an interval in the Y direction. The middle core portion 31, the first side core portion 33a, and the second side core portion 33b connect between the first end core portion 35a and the second end core portion 35b.

[0062] The first side core portion 33a is located on one side in the Y direction. The first side core portion 33a faces a side surface on one side in the Y direction of the outer circumferential surface of the winding portion 20. The one side in the Y direction is the right side of the paper in FIG. 2. An end portion of the first side core portion 33a on one side in the X direction is connected to the first end core portion 35a. An end portion of the first side core portion 33a on the other side in the X direction is connected to the second end core portion 35b.

[0063] The second side core portion 33b is located on the other side in the Y direction. The second side core portion 33b faces the side surface of the outer circumferential surface of the winding portion 20 on the other side in the Y direction. The other side in the Y direction is the left side in FIG. 2. One end of the second side core portion 33b in the X direction is connected to the first end core portion 35a. The other end of the second side core portion 33b in the X direction is connected to the second end core portion 35b.

[0064] Each of the first side core portion 33a and the second side core portion 33b may have a length sufficient to connect the first end core portion 35a and the second end core portion 35b. The shape of each of the first side core portion 33a and the second side core portion 33b is not particularly limited. In this embodiment, the shape of each of the first side core portion 33a and the second side core portion 33b is substantially rectangular parallelepiped. The cross-sectional areas of each of the first side core portion 33a and the second side core portion 33b may be the same or different. In this embodiment, the cross-sectional area of ​​the first side core portion 33a is the same as the cross-sectional area of ​​the second side core portion 33b. In this embodiment, the total cross-sectional area of ​​the first side core portion 33a and the cross-sectional area of ​​the second side core portion 33b is equal to the cross-sectional area of ​​the middle core portion 31. The cross-sectional area here refers to the area of ​​a cross section perpendicular to the X-direction.

[0065] At least one of the first side core portion 33a and the second side core portion 33b may or may not be divided in the X direction. In this embodiment, the first side core portion 33a and the second side core portion 33b are not divided.

[0066] <First core / Second core> The shapes of the first core 3a and the second core 3b can be selected from various combinations. In this embodiment, as shown in Figures 1 and 2, the magnetic core 3 is an ET type that combines an E-shaped first core 3a and a T-shaped second core 3b.

[0067] First Core The first core 3a has, for example, a first end core portion 35a, at least a part of the middle core portion 31, and at least a part of each of the first side core portion 33a and the second side core portion 33b. In this embodiment, as shown in FIG. 2, the first core 3a has the first end core portion 35a, a first middle core portion 31a which is a part of the middle core portion 31, the whole of the first side core portion 33a, and the whole of the second side core portion 33b. The first end core portion 35a, the first middle core portion 31a, the first side core portion 33a, and the second side core portion 33b are integrally molded. Since the first core 3a is an integrally molded body, each core portion constituting the first core 3a is made of the same material. That is, the magnetic properties and mechanical properties of each core portion constituting the first core 3a are substantially the same. The first middle core portion 31a extends in the X direction from a middle portion in the Y direction of the first end core portion 35a toward the second middle core portion 31b. The first side core portion 33a and the second side core portion 33b each extend in the X direction from a Y-direction end portion of the first end core portion 35a toward the second end core portion 35b. The first core 3a has an E-shape when viewed from the Z direction.

[0068] <Second Core> In this embodiment, the second core 3b has a second end core portion 35b and a second middle core portion 31b which is the remaining portion of the middle core portion 31. The second core 3b does not include the first side core portion 33a and the second side core portion 33b. The second end core portion 35b and the second middle core portion 31b are integrally molded. Since the second core 3b is an integrally molded body, each core portion constituting the second core 3b is made of the same material. That is, the magnetic properties and mechanical properties of each core portion constituting the second core 3b are substantially the same. The second middle core portion 31b extends in the X direction from the middle portion of the second end core portion 35b in the Y direction toward the first middle core portion 31a. The shape of the second core 3b is T-shaped when viewed from the Z direction.

[0069] In this embodiment, the magnetic core 3 is composed of two pieces, namely, the first core 3a and the second core 3b. That is, the number of divisions of the magnetic core 3 is two. The number of divisions of the magnetic core 3 and the positions at which the magnetic core 3 is divided are not particularly limited. The magnetic core 3 may be composed of three or more pieces. For example, the first end core portion 35a, the second end core portion 35b, the first middle core portion 31a, the second middle core portion 31b, the first side core portion 33a, and the second side core portion 33b may be individually configured and combined to configure the magnetic core 3. When the magnetic core 3 is composed of the first core 3a and the second core 3b as in this embodiment, the number of core pieces to be combined is only two, so that the magnetic core 3 can be easily assembled.

[0070] (Relationship between the relative permeability of the first end core portion and the relative permeability of the second end core portion) The relative permeability of the second end core portion 35b is greater than that of the first end core portion 35a. That is, the relative permeability of the second core 3b is greater than that of the first core 3a. The relative permeability of each of the first core 3a and the second core 3b may be appropriately set so as to obtain a predetermined inductance while satisfying the above relationship. The relative permeability of the first end core portion 35a is, for example, 5 or more and 50 or less. The relative permeability of the first end core portion 35a may be 10 or more and 45 or less, or further 15 or more and 40 or less. The relative permeability of the second end core portion 35b is, for example, 50 or more and 500 or less. The relative permeability of the second end core portion 35b is preferably 100 or more and 500 or less. The relative permeability of the second end core portion 35b may be 100 or more and 450 or less, or further 150 or more and 400 or less. As long as the relative magnetic permeability of the second end core portion 35b is greater than the relative magnetic permeability of the first end core portion 35a, the relative magnetic permeability of the other core portions is not particularly important.

[0071] The difference between the relative permeability of the second end core portion 35b and the relative permeability of the first end core portion 35a is, for example, not less than 50. In practice, the upper limit of the difference in relative permeability is, for example, about 500. The difference in relative permeability may be 50 or more and 500 or less, or further 100 or more and 400 or less.

[0072] The relative permeability can be determined as follows. A ring-shaped measurement sample is cut out from each of the first end core portion 35a and the second end core portion 35b. Each measurement sample is wound with 300 turns on the primary side and 20 turns on the secondary side. The BH initial magnetization curve is measured in the range of H=0 (Oe) to 100 (Oe), and the maximum value of B / H of this BH initial magnetization curve is determined. This maximum value is the relative permeability. The magnetization curve referred to here is the so-called DC magnetization curve.

[0073] (End core material) The first end core portion 35a and the second end core portion 35b are made of a molded body of a soft magnetic material. Examples of the molded body include a powder compact and a composite material compact. The first end core portion 35a and the second end core portion 35b are made of molded bodies made of different materials. The different materials include not only the case where the materials of the individual components are different in each molded body making up the first end core portion 35a and the second end core portion 35b, but also the case where the materials of the individual components are the same but the contents of the components are different. For example, even if the first end core portion 35a and the second end core portion 35b are made of a powder compact, if at least one of the material and the content of the soft magnetic powder making up the powder compact is different, they are made of different materials. Also, even if the first end core portion 35a and the second end core portion 35b are made of a composite material molded body, if at least one of the material and the content of the soft magnetic powder making up the composite material is different, they are made of different materials.

[0074] The powder compact is formed by compression molding raw material powder containing soft magnetic powder. The powder compact contains a larger amount of soft magnetic powder than the compact of the composite material. Therefore, the powder compact has higher magnetic properties than the compact of the composite material. Examples of the magnetic properties include relative permeability and saturation magnetic flux density. The powder compact may contain a binder resin, a molding aid, and the like. The content of the soft magnetic powder in the powder compact is, for example, 85% by volume or more and 99.99% by volume or less, when the powder compact is taken as 100% by volume.

[0075] The composite material compact is formed by dispersing soft magnetic powder in resin. The composite material compact is obtained by filling a mold with a fluid material in which soft magnetic powder is dispersed in unsolidified resin, and solidifying the resin. The content of the soft magnetic powder in the composite material compact can be easily adjusted. Therefore, the magnetic properties of the composite material compact can be easily adjusted. The content of the soft magnetic powder in the composite material compact is, for example, 20% by volume or more and 80% by volume or less, when the composite material is 100% by volume.

[0076] Examples of the particles constituting the soft magnetic powder include soft magnetic metal particles, coated particles with an insulating coating on the outer periphery of soft magnetic metal particles, and soft magnetic nonmetal particles. Examples of the soft magnetic metal include pure iron and iron-based alloys. Examples of the iron-based alloy include Fe (iron)-Si (silicon) alloys and Fe-Ni (nickel) alloys. Examples of the insulating coating include phosphates. Examples of the soft magnetic nonmetal include ferrites.

[0077] The resin of the composite material molded body may be a thermosetting resin or a thermoplastic resin. Examples of the thermosetting resin include unsaturated polyester resin, epoxy resin, urethane resin, and silicone resin. Examples of the thermoplastic resin include polyphenylene sulfide resin, polytetrafluoroethylene resin, liquid crystal polymer, polyamide resin, polybutylene terephthalate resin, and acrylonitrile-butadiene-styrene resin. Examples of the polyamide resin include nylon 6, nylon 66, and nylon 9T. Other examples of the resin of the composite material molded body include BMC (bulk molding compound), which is a mixture of unsaturated polyester with calcium carbonate and glass fiber, millable silicone rubber, and millable urethane rubber.

[0078] The composite material compact may contain a filler in addition to the soft magnetic powder and the resin. Examples of the filler include ceramic fillers such as alumina and silica. When the composite material compact contains a filler, the heat dissipation properties can be improved. The content of the filler is, for example, 0.2% by volume when the composite material compact is taken as 100% by volume. volume % or more 20 volume % or less, and even 0.3 volume % or more 15 volume % or less, 0.5 volume % or more 10 volume % or less.

[0079] The content of soft magnetic powder in a powder compact or a composite material compact is considered to be equivalent to the area ratio of the soft magnetic powder in the cross section of the compact. The content of soft magnetic powder is determined as follows. The cross section of the compact is observed with a scanning electron microscope (SEM) to obtain an observation image. The magnification of the SEM is, for example, 200 times or more and 500 times or less. Ten or more observation images are obtained. The total area of ​​the observation images is 0.1 cm. 2 That is all. One observation image may be acquired per cross section, or multiple observation images may be acquired per cross section. Each acquired observation image is subjected to image processing to extract the contours of the soft magnetic powder particles. Image processing includes, for example, binarization. The total area of ​​the soft magnetic powder particles in each observation image is calculated, and the area ratio of the soft magnetic powder particles in each observation image is determined. The average value of the area ratios in all observation images is regarded as the soft magnetic powder content.

[0080] In this embodiment, the first core 3a having the first end core portion 35a is a composite material molded body, and the second core 3b having the second end core portion 35b is a powder compact. The first core 3a is made of a composite material molded body, and the second core 3b is made of a powder compact, so that the magnetic properties of the entire magnetic core 3 can be adjusted. In addition, when the first end core portion 35a is made of a composite material molded body, and the second end core portion 35b is made of a powder compact, the relative permeability of each of the first end core portion 35a and the second end core portion 35b is likely to satisfy the above relationship. In this embodiment, the relative permeability of the first end core portion 35a is about 20 to 30, and the relative permeability of the second end core portion 35b is about 150 to 250. The difference between the relative permeability of the second end core portion 35b and the relative permeability of the first end core portion 35a is about 120 to 230.

[0081] <Sensor> The sensor 6 is an element that measures the physical quantities of the reactor 1a. The physical quantities referred to here are various physical quantities that occur in and around the components of the reactor 1a when the reactor 1a is in operation. The components include the coil 2 and the magnetic core 3. Representative physical quantities include current, temperature, and the like.

[0082] Examples of the sensor 6 include a current sensor and a temperature sensor. Examples of the current sensor include a Hall type current sensor using a Hall element, a shunt resistor type current sensor using a shunt resistor, and a magnetoresistive type current sensor using a magnetoresistive element. Examples of the temperature sensor include a thermocouple, a thermistor, and a resistance temperature detector. In this embodiment, the sensor 6 is a current sensor 6a. The current sensor 6a is a Hall type current sensor. The current sensor 6a is provided on a circuit board 60 described later.

[0083] <Circuit Board> As shown in FIG. 2, the reactor 1a includes a circuit board 60 that controls the current flowing through the coil 2. The circuit board 60 includes a current sensor 6a. In this embodiment, as shown in FIG. 3, the circuit board 60 is disposed above the reactor 1a. The circuit board 60 is supported, for example, by a case that houses the reactor 1a. The case is not shown. The circuit board 60 is connected to the terminal portion 21 of the coil 2 via a bus bar (not shown). A current supplied to the coil 2 from a power source (not shown) flows through the circuit board 60. The current sensor 6a measures the current flowing through the coil 2 by measuring the current flowing through the circuit board 60. The current flowing through the coil 2 can also be measured by a current sensor attached to the coil 2.

[0084] (sensor position) When the reactor 1a is viewed from above, the sensor 6 is disposed closer to the second end core portion 35b than the center line between the first end core portion 35a and the second end core portion 35b, as shown in FIG. 2. That is, the sensor 6 is disposed at a position closer to the second end core portion 35b than the first end core portion 35a. The center line between the first end core portion 35a and the second end core portion 35b is a line that bisects the portion between the mutually facing portions of the first end core portion 35a and the second end core portion 35b in the X direction in the plan view. This bisector passes through the center position of the middle core portion 31 in the X direction. The above bisector passes through the center positions of the first side core portion 33a and the second side core portion 33b in the X direction.

[0085] When the reactor 1a is in operation, leakage magnetic flux is generated from the magnetic core 3. The sensor 6 is affected by the leakage magnetic flux from the magnetic core 3. As will be apparent from a test example described later, when the magnetic core 3 has a θ-shaped configuration, there is a lot of leakage magnetic flux from the end core portions 35, particularly the first end core portion 35a, which has a small relative permeability. Therefore, it is preferable to place the sensor close to the second end core portion 35b, which has a large relative permeability.

[0086] The distance Ls from the second end core portion 35b to the sensor 6 is, for example, within 50 mm. The distance Ls is the shortest distance between the second end core portion 35b and the sensor 6. The shortest distance here is the shortest straight-line distance from the surface of the second end core portion 35b to the surface of the sensor 6 in three-dimensional orthogonal coordinates. The distance Ls may be within 45 mm, or even within 40 mm.

[0087] From the viewpoint of reducing the influence of leakage magnetic flux on the sensor 6, it is preferable that the sensor 6 is disposed at a position where the change width ΔB of the magnetic flux density leaking from the magnetic core 3 is 2.0 mT or less. The change width ΔB of the magnetic flux density here is the change width of the magnetic flux density at the position of the sensor 6 when the reactor 1a is operated under the first operating condition. The change width ΔB is the difference between the maximum value and the minimum value of the Z-direction component of the magnetic flux density. The change width ΔB is more preferably 1.9 mT or less. The lower limit of the change width ΔB is, for example, 0.1 mT. The change width ΔB may be 0.1 mT or more and 2.0 mT or less, or further 0.2 mT or more and 1.9 mT or less. The first operating condition is an input voltage of 200 V, a boosted voltage of 400 V, a switching frequency of 20 kHz, and a superimposed current of 100 A.

[0088] Furthermore, the maximum value Bmax of the magnetic flux density is preferably 6.0 mT or less. The maximum value Bmax of the magnetic flux density here is the maximum value of the magnetic flux density at the position of the sensor 6 when the reactor 1a is operated under the first operating condition. The maximum value Bmax is the maximum value of the Z-direction component of the magnetic flux density. The maximum value Bmax is more preferably 5.9 mT or less. The lower limit of the maximum value Bmax is, for example, 0.1 mT. Alternatively, the maximum value Bmax may be 0.1 mT or more and 6.0 mT or less, further 0.1 mT or more and 5.9 mT or less, or 0.2 mT or more and 5.8 mT or less.

[0089] When the reactor 1a is viewed from above, the sensor 6 may be disposed in a region overlapping with the second end core portion 35b. The region overlapping with the second end core portion 35b includes the upper surface of the second end core portion 35b and a space above the upper surface of the second end core portion 35b. The sensor 6 may be disposed on the upper surface of the second end core portion 35b, or may be disposed in an upper space away from the upper surface of the second end core portion 35b. The sensor 6 may also be disposed in a region on an extension line of the middle core portion 31. Disposing in a region on an extension line of the middle core portion 31 means that the sensor 6 is disposed so as to overlap a region sandwiched between both extended edges of the middle core portion 31 when viewed from above. The position of the sensor 6 in the Z direction may be within the range of the dimension of the magnetic core 3 in the Z direction, or may be above the upper surface of the second end core portion 35b.

[0090] <Other> Reactor 1a further includes a resin molded member 4. In Fig. 1, resin molded member 4 is indicated by a two-dot chain line. In Fig. 2 and Fig. 3, resin molded member 4 is omitted.

[0091] (Resin molded parts) The resin molded member 4 covers at least a part of the outer circumferential surface of the magnetic core 3. The resin molded member 4 integrates the combined first core 3a and second core 3b. The resin molded member 4 also integrates the coil 2 and the magnetic core 3. In this embodiment, the resin molded member 4 is also filled between the inner circumferential surface of the winding portion 20 and the middle core portion 31. Therefore, the coil 2 is held in a position relative to the magnetic core 3 by the resin molded member 4. The resin molded member 4 also ensures electrical insulation between the coil 2 and the magnetic core 3. As the resin constituting the resin molded member 4, for example, the same resin as the resin of the above-mentioned composite material molded body can be used. The resin molded member 4 may cover the outer circumferential surface of the winding portion 20. The resin molded member 4 may be formed so that at least one of the upper and lower surfaces of the winding portion 20 is exposed.

[0092] In this embodiment, the resin of the resin molded member 4 passes between the inner circumferential surface of the winding portion 20 and the middle core portion 31 and also fills the gap portion 3g. The gap portion 3g is formed by the resin of the resin molded member 4.

[0093] (holding member) The reactor 1a may further include a retaining member (not shown) as another component. The retaining members are disposed between the first end face 22a of the winding portion 20 and the first end core portion 35a, and between the second end face 22b of the winding portion 20 and the second end core portion 35b. The retaining member determines the relative positions of the coil 2 and the magnetic core 3. The retaining member also ensures electrical insulation between the coil 2 and the magnetic core 3. The retaining member may be made of, for example, the same resin as the resin of the composite material molded body described above.

[0094] [Effects of the First Embodiment] The reactor 1a of the first embodiment can reduce the influence of leakage magnetic flux on the sensor 6. This is because the sensor 6 is disposed on the second end core portion 35b side. In the reactor 1a, the relative permeability of the second end core portion 35b is greater than that of the first end core portion 35a, so the magnetic flux leaking from the second end core portion 35b is less than the magnetic flux leaking from the first end core portion 35a. Therefore, in the reactor 1a, the sensor 6 is disposed on the second end core portion 35b side, so that the influence of leakage magnetic flux on the sensor 6 is smaller than when the sensor 6 is disposed on the first end core portion 35a side. Since the sensor 6 is less susceptible to the influence of leakage magnetic flux, it is easy to accurately measure the physical quantity of the reactor 1a.

[0095] The smaller the relative permeability of the first end core portion 35a, the more leakage magnetic flux from the first end core portion 35a increases. Therefore, when the relative permeability of the first end core portion 35a is 5 or more and 50 or less, there is a great advantage to arranging the sensor 6 on the second end core portion 35b side. Furthermore, when the relative permeability of the second end core portion 35b is 100 or more and 500 or less, the leakage magnetic flux from the second end core portion 35b is reduced. Therefore, the effect of the leakage magnetic flux on the sensor 6 is effectively suppressed.

[0096] When the reactor 1a is operated under the first operating condition, the sensor 6 is arranged at a position where the change width ΔB of the magnetic flux density of the leakage magnetic flux is 2.0 mT or less, so that the sensor 6 is less susceptible to the influence of the leakage magnetic flux. Furthermore, if the sensor 6 is arranged at a position where the maximum value Bmax of the magnetic flux density of the leakage magnetic flux is 6.0 mT or less, the sensor 6 is even less susceptible to the influence of the leakage magnetic flux.

[0097] When the distance Ls from the second end core portion 35b to the sensor 6 is within 50 mm, the sensor 6 can be disposed close to the reactor 1a, thereby increasing the degree of freedom in the layout of the sensor 6.

[0098] The sensor 6 may be disposed in a region overlapping with the second end core portion 35b. When the sensor 6 is disposed in a region overlapping with the second end core portion 35b, the space above the upper surface of the second end core portion 35b can be effectively utilized. Compared with the case where the sensor 6 is disposed in a region not overlapping with the second end core portion 35b, the planar installation space of the reactor 1a including the sensor 6 is smaller. The sensor 6 may be disposed in a region on an extension line of the middle core portion 31. As is clear from a test example described later, the region on this extension line is a region where leakage magnetic flux is more likely to occur than a position shifted in the Y direction from the region on the extension line. However, even if the region on the extension line is on the second end core portion 35b side, the influence of leakage magnetic flux is relatively small. In addition, the sensor 6 can be disposed in a well-balanced position in the Y direction of the reactor 1a.

[0099] [Embodiment 2] A reactor 1b of the second embodiment will be described with reference to Fig. 4. The reactor 1b of the second embodiment differs from the reactor 1a of the first embodiment in that the magnetic core 3 is of an EE type. The following description will focus on the differences from the first embodiment. Configurations similar to those of the first embodiment are given the same reference numerals and descriptions thereof will be omitted. In Fig. 4, the resin molded member 4 described in the first embodiment is omitted.

[0100] <Magnetic core> The magnetic core 3 is configured by combining the first core 3a and the second core 3b in the X direction, similarly to the first embodiment. The magnetic core 3 has a θ-shape when viewed from the Z direction, as shown in FIG.

[0101] In the second embodiment, each of the first side core portion 33a and the second side core portion 33b is divided in the X direction. Each of the first side core portion 33a and the second side core portion 33b has a first portion 331 and a second portion 332. The first portion 331 is located on one side in the X direction. An end of the first portion 331 is connected to the first end core portion 35a. The second portion 332 is located on the other side in the X direction. An end of the second portion 332 is connected to the second end core portion 35b.

[0102] An end face of the first portion 331 and an end face of the second portion 332 are in contact with each other. The lengths of the first portion 331 and the second portion 332 may be set appropriately. The length here refers to the length along the X direction. In FIG. 4, the first portion 331 is longer than the second portion 332. The first portion 331 may be shorter than the second portion 332. The first portion 331 and the second portion 332 may be the same length.

[0103] The first core 3a has a first end core portion 35a, a first middle core portion 31a, and a first portion 331 which is a part of each of the first side core portion 33a and the second side core portion 33b. The first end core portion 35a, the first middle core portion 31a, and the two first portions 331 are integrally molded. Each of the first portions 331 extends in the X direction from both ends of the first end core portion 35a in the Y direction toward the second portion 332. The shape of the first core 3a is E-shaped when viewed from the Z direction.

[0104] The second core 3b has a second end core portion 35b, a second middle core portion 31b, and a second portion 332 which is the remaining portion of each of the first side core portion 33a and the second side core portion 33b. The second end core portion 35b, the second middle core portion 31b, and the two second portions 332 are integrally molded. Each of the second portions 332 extends in the X direction from both ends of the second end core portion 35b in the Y direction toward the first portion 331. The shape of the second core 3b is E-shaped when viewed from the Z direction.

[0105] The relationship between the relative permeability of the first end core portion 35a and the relative permeability of the second end core portion 35b is the same as in embodiment 1. That is, the relative permeability of the second end core portion 35b is greater than the relative permeability of the first end core portion 35a. Also, like embodiment 1, the sensor 6 is disposed on the second end core portion 35b side.

[0106] [Effects of the second embodiment] The reactor 1b of the second embodiment can reduce the effect of leakage magnetic flux on the sensor 6, similarly to the reactor 1a of the first embodiment.

[0107] [Embodiment 3] A reactor 1c of the third embodiment will be described with reference to Fig. 5. The reactor 1c of the third embodiment differs from the reactor 1a of the first embodiment in that the magnetic core 3 is of an EI type. The following description will focus on the differences from the first embodiment. Configurations similar to those of the first embodiment are given the same reference numerals and description thereof will be omitted. In Fig. 5, the resin molded member 4 described in the first embodiment is omitted.

[0108] <Magnetic core> The magnetic core 3 is configured by combining the first core 3a and the second core 3b in the X direction, similarly to the first embodiment. The shape of the magnetic core 3 is a θ shape when viewed from the Z direction, as shown in Fig. 5. In the third embodiment, unlike the first embodiment, the middle core portion 31 is not divided in the X direction.

[0109] The first core 3a has the first end core portion 35a, the whole of the middle core portion 31, the whole of the first side core portion 33a, and the whole of the second side core portion 33b. The first end core portion 35a, the middle core portion 31, the first side core portion 33a, and the second side core portion 33b are integrally molded. The middle core portion 31 extends in the X direction from a middle portion in the Y direction of the first end core portion 35a toward the second end core portion 35b. The end face of the middle core portion 31 may or may not be in contact with the second end core portion 35b. In this embodiment, the end face of the middle core portion 31 is in contact with the second end core portion 35b. When the end face of the middle core portion 31 is not in contact with the second end core portion 35b, a gap portion is formed between the middle core portion 31 and the second end core portion 35b. The shape of the first core 3a is E-shaped when viewed from the Z direction.

[0110] The second core 3b has only the second end core portion 35b. The second core 3b does not include the middle core portion 31, the first side core portion 33a, or the second side core portion 33b. The second core 3b has an I-shape when viewed from the Z direction.

[0111] The relationship between the relative permeability of the first end core portion 35a and the relative permeability of the second end core portion 35b is the same as in embodiment 1. That is, the relative permeability of the second end core portion 35b is greater than the relative permeability of the first end core portion 35a. Also, like embodiment 1, the sensor 6 is disposed on the second end core portion 35b side.

[0112] [Effects of the Third Embodiment] The reactor 1c of the third embodiment can reduce the effect of leakage magnetic flux on the sensor 6, similarly to the reactor 1a of the first embodiment.

[0113] [Variation 1] In the reactors 1a, 1b, and 1c of the above-described first to third embodiments, when a temperature sensor is attached as the sensor 6, the temperature sensor is preferably fixed to the second end core portion 35b of the second core 3b. For example, the temperature sensor may be fixed to the upper surface of the second end core portion 35b. By fixing the temperature sensor to the second end core portion 35b, the influence of leakage magnetic flux on the temperature sensor is reduced compared to when the temperature sensor is fixed to the first end core portion 35a of the first core 3a. When the temperature sensor is fixed to the second end core portion 35b, the temperature of the second end core portion 35b can be measured by the temperature sensor. For example, the temperature sensor may be fixed to the second end core portion 35b by an adhesive, an adhesive tape, solder, or the like.

[0114] [Embodiment 4] [Converter / Power Conversion Device] The reactors of the first to third embodiments can be used for applications that satisfy the following energization conditions. For example, the energization conditions include a maximum DC current of about 100 A to 1000 A, an average voltage of about 100 V to 1000 V, and an operating frequency of about 5 kHz to 100 kHz. The reactors 1a, 1b, and 1c of the first to third embodiments can be used as components of converters mounted on vehicles such as electric vehicles and hybrid vehicles, and as components of power conversion devices equipped with these converters.

[0115] As shown in Fig. 6, a vehicle 1200 such as a hybrid vehicle or an electric vehicle includes a main battery 1210, a power conversion device 1100 connected to the main battery 1210, and a motor 1220 that is driven by power supplied from the main battery 1210 and used for traveling. The motor 1220 is typically a three-phase AC motor that drives wheels 1250 during traveling and functions as a generator during regeneration. In the case of a hybrid vehicle, the vehicle 1200 includes an engine 1300 in addition to the motor 1220. Although Fig. 6 shows an inlet as a charging point for the vehicle 1200, a form including a plug may also be used.

[0116] The power conversion device 1100 includes a converter 1110 connected to a main battery 1210, and an inverter 1120 connected to the converter 1110 and performing mutual conversion between direct current and alternating current. The converter 1110 shown in this example boosts the input voltage of the main battery 1210, which is about 200V to 300V, to about 400V to 700V when the vehicle 1200 is running, and supplies power to the inverter 1120. During regeneration, the converter 1110 lowers the input voltage output from the motor 1220 via the inverter 1120 to a direct current voltage suitable for the main battery 1210, and charges the main battery 1210. The input voltage is a direct current voltage. When the vehicle 1200 is running, the inverter 1120 converts the DC boosted by the converter 1110 into a predetermined AC and supplies it to the motor 1220. During regeneration, the inverter 1120 converts the AC output from the motor 1220 into DC and outputs it to the converter 1110.

[0117] As shown in FIG. 7, the converter 1110 includes a plurality of switching elements 1111, a drive circuit 1112 that controls the operation of the switching elements 1111, and a reactor 1115, and converts the input voltage by repeatedly turning the switching elements 1111 on and off. The conversion of the input voltage means stepping up and down the voltage here. The switching elements 1111 are power devices such as field effect transistors and insulated gate bipolar transistors. The reactor 1115 has a function of smoothing the change when the current increases or decreases due to the switching operation by utilizing the properties of a coil that prevents a change in the current flowing through the circuit. The reactor 1115 includes any of the reactors according to the first to third embodiments. By including any of the reactors according to the first to third embodiments, the physical quantity of the reactor can be easily and accurately measured by a sensor.

[0118] In addition to the converter 1110, the vehicle 1200 includes a power supply converter 1150 connected to the main battery 1210, and an auxiliary power converter 1160 connected to the sub-battery 1230 serving as a power source for the auxiliary devices 1240 and the main battery 1210 to convert the high voltage of the main battery 1210 to a low voltage. The converter 1110 typically performs DC-DC conversion, while the power supply converter 1150 and the auxiliary power converter 1160 perform AC-DC conversion. Some of the power supply converters 1150 perform DC-DC conversion. The reactors of the power supply converter 1150 and the auxiliary power converter 1160 may have the same configuration as the reactors of any of the first to third embodiments, and may be appropriately changed in size, shape, and the like. In addition, the reactors of any of the first to third embodiments may be used as a converter that converts input power and that performs only step-up or step-down.

[0119] [Test Example 1] Regarding the reactor 1a of the first embodiment, the distribution of the magnetic flux density leaking from the magnetic core 3 during operation of the reactor 1a was examined.

[0120] In test example 1, the magnetic flux density distribution on the second end core portion 35b side and the magnetic flux density distribution on the first end core portion 35a side were each analyzed by CAE (Computer Aided Engineering). Analysis example 1 is the analysis of the magnetic flux density distribution on the second end core portion 35b side. Analysis example 2 is the analysis of the magnetic flux density distribution on the first end core portion 35a side. JMAG-Designer19.0 manufactured by JSOL Corporation, which is a commercially available electromagnetic field analysis software, was used to analyze the magnetic flux density distribution. In test example 1, the configuration of the magnetic core 3 was set as follows.

[0121] Relative permeability of first core: 25 Second core relative permeability: 200 Material of the first core: Composite material Second core material: Powder compact

[0122] The reactor 1a was operated under the first operating condition shown below. Input voltage: 200V, Voltage after boost: 400V Switching frequency: 20kHz, Superimposed current: 100A

[0123] (Analysis example 1) With reference to FIG. 8, analysis example 1 of the magnetic flux density distribution on the second end core portion 35b side will be described. In analysis example 1, the Z-direction components of the magnetic flux density at each of the nine measurement points M1 to M9 shown in FIG. 8 were obtained. Here, the position of each measurement point is expressed by three-dimensional coordinates based on a reference point P2 of the second end core portion 35b. The X coordinate of the reference point P2 is located on the boundary between the second end core portion 35b and the middle core portion 31. That is, the X coordinate of the reference point P2 is located on a plane parallel to a plane facing the second end face 22b of the winding portion 20 in the second end core portion 35b. The Y coordinate of the reference point P2 is located on an axis passing through the center of the middle core portion 31. The Z coordinate of the reference point P2 is located on the upper surface of the second end core portion 35b. The three-dimensional coordinates of the reference point P2 of the second core 3b are set as the origin (0,0,0). In the X direction, the direction from the reference point P2 toward the second end core portion 35b is defined as the positive direction of the X coordinate. In the Y direction, the direction from the reference point P2 toward the side core portion 33 is defined as the positive direction of the Y coordinate. In the Z direction, the upward direction from the reference point P2 is defined as the positive direction of the Z coordinate. This upward direction is the direction toward the front of the paper in FIG. 8. The X, Y, and Z coordinates of each measurement point are shown in Table 1. Table 1 also shows the shortest distance Lm from each measurement point to the second end core portion 35b.

[0124] Table 2 shows the maximum magnetic flux density Bmax and the change width ΔB of the magnetic flux density at each measurement point. FIG. 9 shows the time transition of the magnetic flux density at each measurement point. In the graph of FIG. 9, the horizontal axis shows time (s) and the vertical axis shows magnetic flux density (mT). In the graph of FIG. 9, the magnetic flux density value at measurement point M1 is shown by a solid line. The magnetic flux density value at measurement point M2 is shown by a dashed line. The magnetic flux density value at measurement point M3 is shown by a dashed line. The magnetic flux density value at measurement point M4 is shown by a thin solid line. The magnetic flux density value at measurement point M5 is shown by a thin dashed line. The magnetic flux density value at measurement point M6 is shown by a thin dashed line. The magnetic flux density value at measurement point M7 is shown by a thick solid line. The magnetic flux density value at measurement point M8 is shown by a thick dashed line. The magnetic flux density value at measurement point M9 is shown by a thick dashed line.

[0125] [Table 1]

[0126] [Table 2]

[0127] (Analysis example 2) With reference to FIG. 10, a second analysis example of the magnetic flux density distribution on the first end core portion 35a side will be described. In the second analysis example, the Z-direction components of the magnetic flux density at each of the nine measurement points M11 to M19 shown in FIG. 10 were obtained. Here, the position of each measurement point is expressed by three-dimensional coordinates based on a reference point P1 of the first end core portion 35a. The X-coordinate of the reference point P1 is located on the boundary between the first end core portion 35a and the middle core portion 31. That is, the X-coordinate of the reference point P1 is located on a plane parallel to a plane of the first end core portion 35a facing the first end face 22a of the winding portion 20. The Y-coordinate of the reference point P1 is located on an axis passing through the center of the middle core portion 31. The Z-coordinate of the reference point P1 is located on the upper surface of the first end core portion 35a. The three-dimensional coordinates of the reference point P1 of the first core 3a are set as the origin (0,0,0). In the X direction, the direction from the reference point P1 toward the first end core portion 35a is defined as the positive direction of the X coordinate. In the Y direction, the direction from the reference point P1 toward the side core portion 33 is defined as the positive direction of the Y coordinate. In the Z direction, the upward direction from the reference point P1 is defined as the positive direction of the Z coordinate. This upward direction is the direction toward the front of the paper in FIG. 10. The X, Y, and Z coordinates of each measurement point are shown in Table 3. Table 3 also shows the shortest distance Lm from each measurement point to the first end core portion 35a.

[0128] Table 4 shows the maximum magnetic flux density Bmax and the change width ΔB of the magnetic flux density at each measurement point. FIG. 11 shows the time transition of the magnetic flux density at each measurement point. In the graph of FIG. 11, the horizontal axis shows time (s) and the vertical axis shows magnetic flux density (mT). In the graph of FIG. 11, the magnetic flux density value at measurement point M11 is shown by a solid line. The magnetic flux density value at measurement point M12 is shown by a dashed line. The magnetic flux density value at measurement point M13 is shown by a dashed line. The magnetic flux density value at measurement point M14 is shown by a thin solid line. The magnetic flux density value at measurement point M15 is shown by a thin dashed line. The magnetic flux density value at measurement point M16 is shown by a thin dashed line. The magnetic flux density value at measurement point M17 is shown by a thick solid line. The magnetic flux density value at measurement point M18 is shown by a thick dashed line. The value of the magnetic flux density at measurement point M19 is indicated by a thick dashed line.

[0129] [Table 3]

[0130] [Table 4]

[0131] As shown in Table 2 of analysis example 1, the maximum value Bmax at each of the measurement points M1 to M3 is greater than the maximum value Bmax at each of the measurement points M4 to M6. Also, as shown in Table 4 of analysis example 2, the maximum value Bmax at each of the measurement points M11 to M13 is greater than the maximum value Bmax at each of the measurement points M14 to M16. From this result, it can be seen that in both the first end core portion 35a and the second end core portion 35b, the region on the extension line of the middle core portion 31 has more leakage magnetic flux than positions outside the region on the extension line.

[0132] As shown in Table 2 of Analysis Example 1, the maximum value of the maximum value Bmax among all the measurement points from the measurement points M1 to M9 is 5.86 (mT) at the measurement point M2. The maximum value of the change width ΔB among all the measurement points is 1.79 (mT) at the measurement point M2. As shown in Table 4 of Analysis Example 2, the maximum value of the maximum value Bmax among all the measurement points from the measurement points M11 to M19 is 7.72 (mT) at the measurement point M11. The maximum value of the change width ΔB among all the measurement points is 2.41 (mT) at the measurement point M11. Therefore, the maximum value of the maximum value Bmax on the second end core portion 35b side is reduced by about 24% compared to the maximum value of the maximum value Bmax on the first end core portion 35a side. The maximum value of ΔB on the second end core portion 35b side is reduced by about 26% compared to the maximum value of ΔB on the first end core portion 35a side. From this result, it can be seen that when the sensor is arranged on the second end core portion 35b side, the effect of leakage magnetic flux on the sensor can be reduced compared to when the sensor is arranged on the first end core portion 35a side.

[0133] In the analysis example 1, the change width ΔB at all the measurement points is 2.0 mT or less, and the maximum value of the maximum value Bmax is 6.0 mT or less. Therefore, even if the sensor is arranged at a position close to the second end core portion 35b, such as the measurement points M1 and M2, the sensor is not easily affected by the leakage magnetic flux. The sensor can be arranged at a position within 50 mm, particularly within 45 mm, from the second end core portion 35b. When the sensor is arranged on the second end core portion 35b side, the sensor can be arranged close to the reactor 1a, so the layout of the sensor has a high degree of freedom. In contrast, in the analysis example 2, the change width ΔB at the measurement points M11 and M12 is more than 2.0 mT, and the maximum value of the maximum value Bmax is more than 6.0 mT. Therefore, if the sensor is arranged at a position close to the first end core portion 35a, such as the measurement points M11 and M12, the sensor is easily affected by the leakage magnetic flux. There are cases where the sensor cannot be arranged at a position within 50 mm, particularly within 45 mm, from the first end core portion 35a. When the sensor is disposed on the first end core portion 35a side, it may not be possible to dispose the sensor close to the reactor 1a, so the degree of freedom in the layout of the sensor is low.

[0134] [Analysis example 3] The magnetic flux density was obtained when the Z coordinate of measurement point M2 in analysis example 1 was moved upward by +2 mm. The maximum magnetic flux density Bmax and the change in magnetic flux density ΔB when the Z coordinate of measurement point M2 was moved from 0 mm to 16 mm are shown in Table 5. Furthermore, the magnetic flux density was obtained when the Z coordinate of measurement point M11 in analysis example 2 was moved upward by +2 mm. The maximum magnetic flux density Bmax and the change in magnetic flux density ΔB when the Z coordinate of measurement point M11 was moved upward by +2 mm are shown in Table 6.

[0135] [Table 5]

[0136] [Table 6]

[0137] As shown in Tables 5 and 6, in either case, the maximum value Bmax and the variation width ΔB decrease as the amount of movement of the Z coordinate increases.

[0138] [Test Example 2] The leakage magnetic flux density was examined when the reactor 1a of the first embodiment was actually operated. In a second test example, the reactor 1a was actually operated, and the magnetic flux density distribution on the second end core portion 35b side and the magnetic flux density distribution on the first end core portion 35a side were each measured using a gauss meter. The configuration of the magnetic core 3 was the same as that of the first test example.

[0139] In Test Example 2, the Z-direction component of the magnetic flux density was measured at each of the same nine measurement points M1 to M9 as in Analysis Example 1 of Test Example 1. The change width ΔB of the magnetic flux density at each of the measurement points M1 to M9 is shown in Table 7. In addition, the Z-direction component of the magnetic flux density was measured at each of the same nine measurement points M11 to M19 as in Analysis Example 2 of Test Example 1. The change width ΔB of the magnetic flux density at each of the measurement points M11 to M19 is shown in Table 8. [Table 7]

[0140] [Table 8]

[0141] As shown in Tables 7 and 8, even when the reactor 1a is actually operated, it can be seen that the maximum value of ΔB on the second end core portion 35b side is reduced relative to the maximum value of ΔB on the first end core portion 35a side, just as in the analysis results shown in Tables 2 and 4 of Test Example 1. [Explanation of symbols]

[0142] 1a, 1b, 1c reactor 2 Coil 20 Winding section 21 terminal portion, 21a first terminal portion, 21b second terminal portion 22a: first end surface; 22b: second end surface 3. Magnetic core 3a 1st core, 3b 2nd core 31 Middle Core Division 31a first middle core portion, 31b second middle core portion 33 Side core part 33a first side core portion, 33b second side core portion 331 first part, 332 second part 35 End Core Section 35a first end core portion, 35b second end core portion 3g Gap section 4. Resin molded parts 6 sensors, 6a current sensor 60 Circuit Board Ls distance P1, P2 reference point M1, M2, M3, M4, M5, M6, M7, M8, M9 measurement points M11, M12, M13, M14, M15, M16, M17, M18, M19 measurement points 1100 Power conversion device 1110 converter, 1111 switching element, 1112 drive circuit 1115 Reactor, 1120 Inverter 1150 Converter for power supply device, 1160 Converter for auxiliary power supply 1200 vehicles 1210 Main battery, 1220 Motor, 1230 Sub battery 1240 Auxiliary equipment, 1250 Wheels 1300 Engine

Claims

1. A reactor including a coil and a magnetic core; a sensor for measuring a physical quantity of the reactor, The coil has a cylindrical winding portion, The magnetic core has first and second end core portions, a middle core portion, and first and second side core portions, the middle core portion has a portion disposed inside the winding portion, the first side core portion and the second side core portion are arranged side by side on the outside of the winding portion so as to sandwich the middle core portion, the middle core portion, the first side core portion, and the second side core portion connect between the first end core portion and the second end core portion, the second end core portion has a relative permeability greater than the relative permeability of the first end core portion; The sensor is disposed on the second end core portion side with respect to a center line between the first end core portion and the second end core portion. Reactor.

2. The reactor according to claim 1 , wherein the first end core portion has a relative magnetic permeability of 5 or more and 50 or less.

3. The reactor according to claim 2 , wherein the second end core portion has a relative magnetic permeability of 100 or more and 500 or less.

4. The reactor according to claim 1 , wherein a distance from the second end core portion to the sensor is within 50 mm.

5. the sensor is disposed at a position where a change width of a magnetic flux density leaking from the magnetic core is 2.0 mT or less when the reactor is operated under a first operating condition, 5. The reactor according to claim 1, wherein the first operating condition is an input voltage of 200 V, a boosted voltage of 400 V, a switching frequency of 20 kHz, and a superimposed current of 100 A.

6. The reactor according to claim 5 , further comprising a maximum value of the magnetic flux density of 6.0 mT or less.

7. The reactor according to claim 5 or 6, wherein the sensor is disposed in a region overlapping with the second end core portion when the reactor is viewed in a plan view.

8. The reactor according to claim 5 , wherein the sensor is disposed in a region on an extension of the middle core portion when the reactor is viewed from above.

9. A circuit board for controlling a current flowing through the coil is provided. the sensor is a current sensor; The reactor according to claim 1 , wherein the current sensor is provided on the circuit board.

10. the sensor is a temperature sensor; The reactor according to claim 1 , wherein the temperature sensor is fixed to the second end core portion.

11. the first end core portion is formed of a molded body of a composite material in which soft magnetic powder is dispersed in a resin, The reactor according to claim 1 , wherein the second end core portion is formed of a compact made of raw material powder containing soft magnetic powder.

12. A reactor according to any one of claims 1 to 11, converter.

13. A converter comprising: Power conversion equipment.

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