JP2010171358A - Reactor assembly - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small reactor assembly capable of performing voltage step-up and step-down operation and soft switching, and to provide a method of adjusting the leak inductance of the reactor assembly. <P>SOLUTION: The reactor assembly 1A includes: an annular core 10 having a pair of juxtaposed coil winding parts; an inner coil part 11 having inner coils 11a and 11b; and an outer coil part 12 having outer coils 12a and 12b. The coils 11a and 12a are arranged concentrically in one coil winding part, while the coils 11b and 12b are arranged concentrically in the other coil winding part. One end portion of a winding 11w of the inner coil part 11 is bonded to one end portion of a winding 12w of the outer coil part 12. Since the axial center position of the inner coil 11a and the axial center position of the outer coil 12a are shifted in the axial direction of the coil 11a (12a), predetermined leak inductance can be obtained. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a reactor assembly suitable for components of a power conversion device such as a DC-DC converter mounted on a vehicle such as a hybrid vehicle, and a method for adjusting a leakage inductance of the reactor assembly. In particular, the present invention relates to a reactor assembly that can obtain a desired leakage inductance.

  As a vehicle-mounted component such as a hybrid vehicle or an electric vehicle that uses a motor as a drive source or a power generation source during regeneration, there is a power conversion device that performs a step-up operation or a step-down operation between the motor and the power source. The power converter includes a converter that changes the magnitude of power.

  There is a bidirectional DC-DC converter as an in-vehicle converter (FIG. 6 of Patent Document 1). As a component of this converter, there is a reactor that smoothes a current generated by ON / OFF switching operation of a switching element. As shown in FIG. 8, the reactor L includes an annular core 100 made of a magnetic material, and a coil unit 110 that is formed by winding a winding 111 and has a pair of coils 110a and 110b disposed on the outer periphery of the core 100. A typical structure is shown (FIG. 1 in Patent Document 1). The core 100 includes a pair of coil winding portions (not shown) inserted into the coils 110a and 110b, respectively, and a pair of end cores 100e arranged so as to sandwich the coil winding portions arranged in parallel. . For example, the reactor L is housed in a case (not shown) and sealed with potting resin (FIG. 3 in Patent Document 1), and this case is used by being fixed to a cooling base.

  In recent years, a resonance type DC-DC converter capable of soft switching with less switching loss than conventional converters has been studied (Patent Documents 2 and 3). The converter includes an auxiliary circuit including a resonance reactor and a resonance switching element in addition to the smoothing reactor. Patent Document 3 discloses a configuration including an inductor L1 and an inductor L2, and an inductor Lr having an inductance value smaller than both inductors L1 and L2 (Patent Document 3 FIG. 1). The inductor L1 functions as a smoothing reactor, and soft switching is realized by the inductors L2 and Lr.

JP 2007-116066 JP2003-033013 JP 2007-043852 A

  However, Patent Documents 2 and 3 do not disclose a specific structure of a reactor (inductance, inductor) capable of soft switching. For example, it is conceivable that the smoothing reactor and the resonance reactor are independent members. However, since this configuration requires a space for installing both reactors, it is not preferable for in-vehicle components that require a small installation area and a small size. In addition, switching loss can be reduced by using the inductor Lr as described in Patent Document 3. However, when the inductor Lr is a separate member independent of the smoothing reactor, the reactor assembly including the inductor Lr becomes larger by the inductor Lr.

  In order to reduce the installation area, for example, in the reactor L shown in FIG. 8, a configuration in which the core 100 is shared and used for smoothing and resonance can be considered. For example, another coil is arranged on the end core 100e where the coils 110a and 110b are not arranged, and a resonance reactor is configured by the other coil and the core 100, and the coil unit 110 and the core 100 are used for smoothing. It is possible to construct a reactor. However, in this configuration, not only the other coil protrudes outside the end core 100e but also the other coil is arranged on the end core 100e so as not to contact the coils 110a and 110b. The coil winding portion also needs to be elongated in the axial direction of the coil 110a (110b). Therefore, the length of the coil 110a (110b) in the reactor L in the axial direction is increased, and the other coil also protrudes, thereby increasing the installation area.

In order to reduce the installation area, the inventor does not arrange another coil in the end core 100e, but arranges coils 110a and 110b that function as a smoothing reactor as shown in FIG. A configuration was examined in which the coils 120a and 120b functioning as a resonance reactor were also arranged in the coil winding portions 100c _a and 100c _b . That is, a configuration in which the smoothing coil part 110 and the resonance coil part 120 are arranged so as to be adjacent in the axial direction was examined. In particular, it was examined that leakage inductance generated by providing a gap between the coil portions 110 and 120 is used for the inductor Lr. In this case, the reactor assembly can be made smaller as compared with the case where the inductor Lr is a separate member. However, this configuration has increased leakage inductance. If the leakage inductance is too large, problems such as an increase in the current pulse width may occur when performing soft switching, and soft switching may not be performed properly.

  Therefore, one of the objects of the present invention is to provide a reactor assembly that can be soft-switched while being small. Another object of the present invention is to provide a method for adjusting the leakage inductance from which the reactor assembly is obtained.

  The present invention shares a core in which a coil functioning as a smoothing reactor and a coil functioning as a resonance reactor are shared, and the coils are arranged concentrically on the core, and the axes of the coils The above object is achieved by devising the relative position of the direction.

  Specifically, the reactor assembly of the present invention includes an annular core, and an inner coil portion and an outer coil portion disposed on the outer periphery of the annular core. The annular core includes a pair of coil winding parts arranged in parallel and a pair of end cores arranged so as to sandwich both coil winding parts. The inner coil portion is formed by winding a winding spirally and has an inner coil disposed on the outer periphery of at least one coil winding portion. The outer coil portion is formed by spirally winding a winding different from the winding forming the inner coil portion, and has an outer coil disposed on the outer periphery of at least one coil winding portion. And one outer coil is coaxially arrange | positioned on the outer periphery of one inner coil arrange | positioned at the outer periphery of one coil winding part. When the inner coil portion has a pair of inner coils disposed on the outer periphery of each coil winding portion and the outer coil portion has a pair of outer coils respectively disposed on the outer periphery of each coil winding portion, One outer coil is coaxially disposed on the outer periphery of one inner coil disposed on the outer periphery of the coil winding portion, and the other outer coil is disposed on the outer periphery of the other coil winding portion. The outer coil is arranged coaxially. And the one end part of the coil | winding which comprises said one inner side coil, and the one end part of the coil | winding which comprises said one outer side coil are joined. In addition, the axial center position of the outer coil and the axial center position of the inner coil are shifted in the axial direction.

  The reactor assembly of the present invention is obtained, for example, by the method for adjusting the leakage inductance of the reactor assembly of the present invention. In the method for adjusting the leakage inductance of the reactor assembly according to the present invention, an inner coil formed by winding a winding in a spiral shape is disposed on the outer periphery of an annular core, and the winding is spirally wound around the outer periphery of the inner coil. A rotating outer coil is arranged coaxially with the inner coil. Then, the axial center position of the outer coil and the axial center position of the inner coil are relatively shifted so that a predetermined leakage inductance is obtained.

  According to the reactor assembly of the present invention, for example, the inner coil portion and the core function as a smoothing reactor, and the outer coil portion and the same core function as a resonance reactor. Soft switching can be performed. In particular, according to the reactor assembly of the present invention, the inner coil and the outer coil are concentrically arranged not in the end core but in the coil winding part, so that compared with the case where another coil is arranged in the end core. Thus, the length of the reactor assembly (the axial length of the coil disposed in the coil winding portion) can be shortened. Further, according to the reactor assembly of the present invention, the two coils are concentric rather than a vertically arranged structure in which the inner coil and the outer coil are arranged adjacent to each other in the axial direction with respect to one coil winding portion. Since the stacked structure is stacked, the length of the reactor assembly can be shortened and the installation area can be reduced as compared with the vertical structure.

  In addition, according to the reactor assembly of the present invention, the leakage inductance can be reduced and the outer coil arranged concentrically as compared with the above-described vertical arrangement in which two coil portions are arranged next to each other. Since the center position in the axial direction and the center position in the axial direction of the inner coil are shifted, a leakage inductance corresponding to this shift amount (distance in the axial direction) can be obtained. This leakage inductance can be used for an inductor Lr as described in Patent Document 3, for example. That is, the reactor assembly of the present invention can integrally include the inductor L1 functioning as a smoothing reactor and the inductors L2 and Lr functioning as a resonance reactor. Therefore, the reactor assembly of the present invention has a small installation area and a small size, and also can perform soft switching well. Hereinafter, the present invention will be described in more detail.

  As the shift amount of the center position between the outer coil and the inner coil is smaller, the leakage inductance tends to be smaller. For example, when the coil specifications (winding cross-sectional area, axial length, number of turns, etc.) are constant between the inner and outer coils arranged concentrically, the deviation amount is zero, i.e. both When the axial center positions of the coils are equal, the leakage inductance is the smallest. The deviation amount can be adjusted so that a desired leakage inductance is obtained. However, as the amount of deviation increases, the total axial length of the inner and outer coils arranged concentrically increases, so that the coil winding portion in which these coils are arranged becomes longer, and the reactor assembly Leads to an increase in size. Therefore, if the axial length of one coil of the inner coil and the outer coil is shorter than the axial length of the other coil, the reactor assembly can be downsized even if the shift amount is large. Further, in the inner coil and the outer coil arranged concentrically, the configuration in which the center positions of both coils are relatively shifted may be formed on the outer periphery of the inner coil so that the center position is shifted. It can be easily formed by moving one coil after concentrically arranging both coils. When moving one coil, the center position can be easily shifted by moving the coil having a short axial length. For example, if one coil has fewer turns than the other coil, uses thin windings, or narrows the spacing between adjacent turns that make up the coil, the axial length can be reduced. . If this short coil is an outer coil, it can be easily arranged concentrically or formed on the outer periphery of the inner coil, and the above-mentioned coil can be easily moved.

  In the reactor assembly of the present invention, each winding constituting the inner coil portion and the outer coil portion is preferably provided with an insulating coating layer on the outer periphery of the conductor so that adjacent turns are insulated. Available to: For example, a covered electric wire including a stranded wire conductor obtained by twisting a plurality of strands and an insulating coating layer provided on the outer periphery of the stranded wire conductor can be given. Since the said covered electric wire is generally soft and easy to wind by hand, an outer coil can be easily made to exist in the outer periphery of an inner coil by winding a covered electric wire around the outer periphery of an inner coil, for example. When the insulating coating layer is made of a material having excellent insulating properties, for example, tetrafluoroethylene-hexafluoropropylene copolymer (FEP) resin, polytetrafluoroethylene (PTFE) resin, silicon rubber, etc., it is concentric. It is possible to sufficiently insulate between the inner coil and the outer coil that are disposed on each other. When the winding constituting at least one of the inner coil portion and the outer coil portion is a covered electric wire having excellent insulation properties, sufficient insulation is ensured between the inner coil and the outer coil arranged concentrically. it can.

  Examples of the winding other than the above-described covered electric wire include a covered rectangular wire or a covered round wire including a conductor made of a flat wire or a round wire and an insulating coating layer made of enamel resin or the like on the outer periphery of the conductor. Since the coated round wire is generally soft and can be wound by hand, a coil having a laminated structure (multilayer structure) can be easily formed in the same manner as the above-described coated electric wire, and a coil having a high space factor can be obtained. Since the coated rectangular wire generally has high rigidity, a coil can be formed by winding with a winding machine, and a coil with a particularly high space factor can be obtained. In addition, the coil formed by the covered rectangular wire is not easily deformed and can be easily moved when one coil is shifted after the inner coil and the outer coil are arranged concentrically.

  When the windings constituting both the inner coil portion and the outer coil portion are the above-described covered round wire or covered flat wire, that is, when the coils made of the covered round wire or the covered rectangular wire are arranged concentrically, It is preferable to separately provide an insulating material between the outer coil and the two coils, so that the two coils can be more reliably insulated. For example, insulating paper can be used as the insulating material. Insulating paper is generally thin, and even if it is interposed between the coils, it is difficult to affect the size of the reactor assembly, and the material cost is low and economical. Alternatively, an insulating member such as a cylindrical bobbin formed by molding an insulating resin can be used as the insulating material. In particular, if the positioning portion of the inner coil or the outer coil is formed on this cylindrical bobbin, each coil can be easily disposed at a predetermined position when the inner coil and the outer coil are displaced in the axial direction. Moreover, it is easy to prevent further deviation from a predetermined position.

  When the winding of one coil part is the said covered electric wire among the inner coil part and the outer coil part, and the winding of the other coil part is a covered round wire or a covered flat wire, Since the insulating property is excellent, the insulating material may not be interposed. In this case, since an insulating material is unnecessary, the number of parts can be reduced.

  In at least one of the inner coil portion and the outer coil portion, the coil included in the coil portion can be an edgewise coil obtained by edgewise winding the covered rectangular wire.

  Since the space factor of the coil can be increased by using the covered rectangular wire as described above, the axial length of the coil can be shortened. Therefore, the axial length of the coil winding portion where the coil is disposed can be reduced. The reactor assembly can be reduced in size.

  When a pair of coils is provided in each of the inner coil portion and the outer coil portion, the pair of coils in each coil portion may be formed from separate windings or formed from one continuous winding. A configuration may be adopted. In the former case, one end of each of the windings constituting the pair of coils is joined and connected by welding or the like to form one coil part (hereinafter, this form is called a joined coil), and the latter In this case, one coil part is formed by connecting a pair of coils via a turn-up part formed by folding a part of the winding and a transition part comprising a part of the winding (hereinafter, this form) Is called a continuous coil). Both coil parts may be a joined coil or a continuous coil, one coil part may be a joined coil, and the other coil part may be a continuous coil. For welding, for example, TIG welding, laser welding, resistance welding, or the like can be used. As a method for joining windings other than welding, crimping, cold welding, vibration welding, or the like can be used. The welding can be easily joined and is excellent in workability. In the cold welding, since the winding is not substantially heated at the time of joining, the insulation coating layer on the conductor surface is less likely to be damaged by heating.

  In at least one of the inner coil portion and the outer coil portion, when the pair of coils constituting the coil portion is the edgewise coil and the junction coil, both coils constituting the coil portion are separable. Therefore, it is easy to arrange with respect to the coil of the other coil part, and the assembly workability is excellent. In addition, it is easy to move the coils for relatively shifting the axial center positions of the inner and outer coils. In particular, when both coil portions are joined coils, it is easier to assemble a coil having a laminated structure. In addition, the coated rectangular wire can secure a sufficient contact area during welding and the like, so that it is easy to join and has high joining strength. The connection work for connecting the pair of coils in the coil portion can be performed at any time, but if the laminated coil is assembled and the center position is relatively shifted, the assembly work and the movement of the coil can be performed. Easy to do.

  When at least one of the inner coil portion and the outer coil portion, the pair of coils constituting the coil portion is the edgewise coil and the continuous coil, connection work such as welding is unnecessary.

  Moreover, when the coil | winding which comprises an outer side coil part is the said covering flat wire, an outer side coil can be made into the flatwise coil which wound this covering flat wire flatwise. According to this configuration, the height of the outer coil (size in the direction orthogonal to both the axial direction of the coil and the parallel direction of the pair of coils) and the outer coil are compared with the case where the outer coil is an edgewise coil. The width (the size of the pair of coils in the parallel direction) can be reduced, and the reactor assembly can be further reduced in size. In particular, when the number of turns of the outer coil is small, the axial length of the outer coil is shortened, so that a small reactor assembly can be obtained. In this configuration, the winding forming the inner coil portion can be applied to any of a covered electric wire, a covered flat wire, and a covered round wire.

  In the case where the outer coil portion is used as an element of a resonance reactor, the current flowing through the outer coil portion is relatively small. Therefore, a winding having a small conductor cross-sectional area and a winding having a low conductor conductivity can be used. For example, a conductor made of aluminum or an aluminum alloy can be used as a winding conductor constituting the outer coil portion. Aluminum or an aluminum alloy is lighter in weight, although it has a lower electrical conductivity than copper or a copper alloy, and can contribute to reducing the weight of the reactor assembly.

  Or what consists of a sheet-like wire material by which the insulating material was laminated on the surface of a foil-like conductor as a coil | winding which comprises the said outer side coil part can be utilized. According to this structure, since the thickness of the coil | winding which comprises an outer coil part is thin, the height of an outer coil can be made small and a reactor assembly can be made further small. Examples of the constituent material of the foil-like conductor include copper, copper alloy, aluminum, and aluminum alloy.

  The joining of one end of the winding of the inner coil part and the one end of the winding of the outer coil part is a form in which the conductors are directly joined or terminal members attached to one end of the winding, respectively. Are connected by bolts or the like. For direct joining between the conductors, welding such as TIG welding, laser welding, resistance welding, etc., crimping, cold welding, vibration welding, etc. can be used. In this directly joined form, one terminal member can be used in common with respect to the joined end portions, so that the number of terminal members can be reduced. In particular, when at least one winding of the two coil portions is the covered rectangular wire, that is, when both the coil portions are formed of a covered rectangular wire, or one coil portion is formed of a covered rectangular wire, and the other coil portion is In the case of a covered round wire or a covered electric wire, the contact area can be sufficiently ensured as described above, and the bonding strength can be increased if the form is directly bonded. On the other hand, the welding, pressure bonding, or the like can be used for attaching the terminal member. In the form in which both coil portions are joined via this terminal member, it can be used for any kind of winding.

  The combination of the core, the inner coil portion, and the outer coil portion can be used as a reactor assembly as it is. Furthermore, when it is configured to have a resin coating that covers the outer periphery of the combined body, it is easy to handle the combined body as an integrated object even when it does not have a case. It can be protected from the external environment or mechanically protected.

  The reactor assembly of the present invention can perform soft switching well in addition to the step-up operation and the step-down operation, and is small in size. The method for adjusting the leakage inductance of the reactor assembly of the present invention can form the reactor assembly of the present invention.

FIG. 1 is a schematic perspective view of a reactor assembly according to the first embodiment. FIG. 2 is a schematic explanatory view for explaining the arrangement state of the annular core and the coil constituting the reactor assembly, and FIG. 2 (A) shows that the axial center positions of the inner coil and the outer coil are relatively FIG. 2 (B) shows a reactor assembly that is displaced in the axial center position between the inner coil and the outer coil. Fig. 3 is a schematic cross-sectional view of a winding used in a reactor assembly. Fig. 3 (A) is a covered rectangular wire, Fig. 3 (B) is a covered wire, and Fig. 3 (C) is a covered round wire. Indicates. FIG. 4 is a schematic explanatory view showing a form of a coil portion provided in the reactor assembly, and FIG. 4 (A) is a diagram in which a pair of coils provided in one coil portion are connected via a winding portion. FIG. 4B shows an example of a coil in which a pair of coils included in one coil portion is formed by different windings. FIG. 5 is a schematic perspective view of the reactor assembly shown in Embodiment 4 in which a coated round wire is used for the winding of one coil part, and FIG. 5 (A) is insulated between the inner coil and the outer coil. An example in which paper is interposed, FIG. 5B is an example in which a cylindrical bobbin is interposed between an inner coil and an outer coil. FIG. 6 is an exploded perspective view schematically illustrating a reactor assembly in which a cylindrical bobbin is interposed between an inner coil and an outer coil according to the fourth embodiment. FIG. 7 is a schematic explanatory view of a reactor assembly in which two coil portions are arranged adjacent to each other in the axial direction of the coil. FIG. 8 is a perspective view showing an example of a conventional reactor.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(Embodiment 1: Inner coil-covered rectangular wire, outer coil-covered electric wire)
The reactor assembly 1A according to the first embodiment will be described mainly with reference to FIGS. Hereinafter, the same reference numerals in the drawings indicate the same names. In FIG. 1 and FIG. 5 to be described later, a clearance is provided between the outer peripheral surface of the inner coil and the inner peripheral surface of the outer coil for easy understanding. The Further, in FIG. 2, the connection portion of the end portion of the winding, the rewinding portion, and the end of the winding is omitted.

  The reactor assembly 1A includes an annular core 10 and an inner coil portion 11 and an outer coil portion 12 that are disposed on the outer periphery of the core 10. The inner coil portion 11 includes a pair of inner coils 11a and 11b arranged in parallel, and the outer coil portion 12 includes a pair of outer coils 12a and 12b arranged in parallel. The core 10 and the inner coil unit 11 function as, for example, a smoothing reactor that smoothes a current generated by an ON / OFF switching operation of a switching element included in the converter. The core 10 and the outer coil section 12 function as a resonance reactor used for soft switching in order to reduce the loss of the switching operation. The reactor assembly 1A is characterized by having a core 10 (coil winding portion 10c (FIG. 2 (A))) common to the inner coil portion 11 and the outer coil portion 12, and an outer coil 12a ( 12b) is relatively shifted from the axial center position of the inner coil 11a (11b). Hereinafter, each configuration will be described in more detail.

[Core 10]
The core 10 will be described with reference to FIG. 2 and FIG. The core 10 includes a pair of rectangular parallelepiped coil winding portions 10c _a and 10c _{b in} which each coil pair ((inner coil 11a, outer coil 12a), (inner coil 11b, outer coil 12b)) is disposed, 11a, 11b, 12a, and 12b have a pair of end cores 10e that are not substantially disposed. The core 10 is formed in a closed loop shape (annular shape) with an end core 10e disposed so as to sandwich the coil winding portions 10c _a and 10c _b that are spaced apart in parallel. The core 10 includes a magnetic body portion 10m made of a soft magnetic material containing iron such as iron or steel and a gap material (not shown) made of a nonmagnetic material such as alumina. The coil winding portion 10c is configured by alternately laminating core pieces made of magnetic body portions 10m and gap members. Each core piece can be a soft magnetic powder compact or a laminate of a plurality of electromagnetic steel plates. The gap material is a member disposed in a gap provided between the core pieces for adjusting the inductance (there may be an air gap). The core piece and the gap material are integrally joined with, for example, an adhesive. The number of core pieces divided and the number of gap members can be appropriately selected so that the inner coil portion 11 and the outer coil portion 12 each have a desired inductance.

[Inner coil section 11]
The inner coil portion 11 is formed by winding a single continuous winding 11w (FIG. 1), and includes a pair of inner coils 11a and 11b. The inner coils 11a and 11b are arranged in parallel so that the axial directions of the coils are parallel. As shown in FIG. 3 (A), the winding 11w is a covered rectangular wire having an enamel coating (insulating coating layer) 11i made of polyamideimide on the surface of a conductor 11c made of a copper flat wire. Both coils 11a and 11b are edgewise coils formed by edgewise winding the covered rectangular wire, and are wound back by folding a part of the winding 11w as shown in FIGS. 1 and 4 (A). It is connected via the part 11r. The coils 11a and 11b are arranged in parallel so that the number of turns is equal, the lengths in the axial direction are equal, and the end faces are substantially flush.

  Both end portions 11e (FIGS. 1 and 4A) of the winding 11w are appropriately extended, and terminal members (not shown) are connected to the respective ends, and the outer coil portion 12 is connected to the terminal member on one end side. Is connected to a terminal member (not shown) attached to one end of the winding 12w (FIG. 1). An external device (not shown) such as a power source for supplying power is connected to each of the coil portions 11 and 12 through these terminal members. Welding such as TIG welding, laser welding, or resistance welding can be suitably used to connect the end 11e of the winding 11w that forms the inner coils 11a and 11b and the terminal member.

[Outer coil section 12]
The outer coil portion 12 is formed by winding a single continuous winding 12w like the inner coil portion 11, and includes a pair of outer coils 12a and 12b. The outer coils 12a and 12b are also juxtaposed so that the axial directions of the coils are parallel to each other, and are connected via a crossover (not shown) that connects the outer coils 12a and 12b. The winding 12w is a covered electric wire having an insulation coating layer 12i made of FEP resin on the outer periphery of a stranded wire conductor 12c obtained by twisting a plurality of copper wires 12s as shown in FIG. 3 (B). The coils 12a and 12b are arranged in parallel so that the number of turns is equal, the length in the axial direction is equal, and the end faces are substantially flush. In the example shown in FIG. 1, the number of turns of the outer coil 12a (12b) is less than the number of turns of the inner coil 11a (11b), and the axial length of the outer coil 12a (12b) is smaller than that of the inner coil 11a (11b). It is shorter than the axial length.

  Both end portions 12e (FIG. 1) of the winding 12w are appropriately extended in the same manner as the inner coil portion 11, and the terminal members are connected to each as described above. In particular, the terminal member on one end side of the winding 12w is connected to the terminal member on one end side of the winding 11w constituting the inner coil portion 11 as described above, so that the winding 11w of the inner coil portion 11 One end portion and one end portion of the winding 12w of the outer coil portion 12 are joined via the terminal member.

[Placement of coil relative to core]
And one of the inner coil 11a of the inner coil portion 11, and one of the outer coil 12a of the outer coil portion 12 is disposed on one coil winding portion 10c _a core 10, and the other inner coil 11b of the inner coil portion 11 , the other of the outer coil 12b of the outer coil portion 12 is disposed on the other of the coil winding portion 10c _b of the core 10. In particular, the outer coil 12a (12b) is coaxially disposed on the outer periphery of the inner coil 11a (11b). That is, the inner coil 11a (11b) and the outer coil 12a (12b) are concentrically stacked and arranged.

In this reactor assembly 1A, the axial center position of the inner coil 11a (11b) (indicated by the alternate long and short dash line in FIG. 2) and the axial center position of the outer coil 12a (12b) are the distance in the axial direction. with a shift by l, the coil portion 11, 12 is arranged a coil winding part 10c _a, a 10c _b. In the example shown in FIG. 2 (A), one end face of the outer coil 12a (12b) protrudes from one end face of the inner coil 11a (11b), and in the example shown in FIG. 1, the one end face is aligned. ing.

[Insulator]
When the insulator 14 (FIG. 1) is provided between the core 10 and the inner coil portion 11, the insulation between the core 10 and the inner coils 11a and 11b can be enhanced. The insulator 14 is, for example, a pair of parts that are in contact with cylindrical portions 14b (FIG. 6 to be described later) covering the outer circumferences of the coil winding portions 10c _a and 10c _b and the respective end surfaces of the coils 11a, 11b, 12a, and 12b. And a frame-shaped portion 14f. As shown in FIG. 6, the cylindrical portion 14b can easily cover the outer periphery of the coil winding portion 10c by engaging half-cut cylindrical pieces. Each frame-like portion 14f is a rectangular frame arranged at one end of the cylindrical portion 14b, and a base on which the rewinding portion 11r is placed as one frame-like portion 14f as shown in FIGS. If the structure is provided with a portion, the insulation can be enhanced. Insulator 14 and cylindrical bobbin 14C (described later, FIG. 6) (insulating member) using insulating materials such as polyphenylene sulfide (PPS) resin, polytetrafluoroethylene (PTFE) resin, and liquid crystal polymer (LCP) are used. it can.

[Case or resin coating]
The combination of the core 10, the inner coil portion 11, and the outer coil portion 12 is housed in, for example, an aluminum case (not shown), and further filled with an insulating potting resin (not shown). It can be configured. Using a band-like stay (not shown), etc., fix the end core to the case, or provide a bolt hole in the end core and screw the bolt into this bolt hole to fix the assembly to the case. Also good.

  Or it is good also as a structure which does not store the said assembly in a case, coat | covers with insulating resin, and provides a resin coating part (not shown). For example, epoxy resin, urethane resin, PPS resin, polybutylene terephthalate (PBT) resin, acrylonitrile-butadiene-styrene (ABS) resin, or the like can be used as the constituent resin of the resin coating portion. By omitting the case, the reactor assembly can be further reduced in size. In addition, the heat of the core and the coil is cooled by exposing the surface of the cooling base side when a part of the core and part of the coil, especially the reactor assembly is installed on the cooling base from the resin coating. Easily released to the base, etc., improving heat dissipation. Furthermore, when the case is omitted and the resin coating portion is provided, the end portions of the windings of both coil portions can be drawn out to an arbitrary location, and the degree of freedom in designing the location where the terminal member is connected is increased. Can be bigger.

  In addition, both ends of the windings of both coil parts are exposed from the potting resin or the resin coating part so that the windings can be connected to each other or the terminal member described above can be connected. In this way, by storing the assembly in a case or having a resin coating portion, the core 10, the inner coil portion 11, and the outer coil portion 12 can be protected from the external environment or mechanically protected. , Can make the association easier to handle. These cases and resin coating portions can also be applied to embodiments and modifications described later.

[Assembly of reactor assembly]
Reactor assembly 1A having the above-described configuration can be formed as follows. Hereinafter, FIG. 6 will be referred to as appropriate.

First, the core piece and the gap material are fixed with an adhesive or the like to form the coil winding portions 10c _a and 10c _b, and the cylindrical portion 14b of the insulator 14 is disposed on the outer periphery thereof. Separately, flat wire wound was placed in the coil winding portion 10c _a the coil 11a is tubular portion 14b disposed in the inner coil portion 11 which has been fabricated, the coil 11b, the cylindrical portion 14b is distribution The coil winding portion 10c _b is arranged. Next, one frame-like portion 14f of the insulator 14 and one end core 10e are brought into contact with one end face of the inner coils 11a, 11b, and the other frame of the insulator 14 is brought into contact with the other end face of the inner coils 11a, 11b. 14f and the other end core 10e are brought into contact with each other, and the frame-like portion 14f and the end core 10e are arranged so that the inner coils 11a and 11b are sandwiched between the both end cores 10e, and the end core is formed with an adhesive or the like. 10e and both coil winding parts 10c _a and 10c _b are joined. By this step, a pre-combination of the annular core 10 and the inner coil portion 11 is formed. The rewinding part 11r is placed on the base part of the frame-like part 14f.

  And after winding the covered wire around the outer periphery of the inner coil 11a to form the outer coil 12a, this covered wire is passed to the inner coil 11b side, and the outer coil 12b is wound around the outer periphery of the inner coil 11b by winding the covered wire. Form. The outer coils 12a, 12b are formed at arbitrary positions on the outer periphery of the inner coils 11a, 11b, and then the outer coils 12a, 12b are obtained so as to obtain a predetermined leakage inductance, that is, a predetermined deviation amount l. Is moved in the axial direction to adjust the center position of the outer coils 12a and 12b. The shift amount l may be appropriately selected from the following relational data created in advance. Relevant data can be obtained by, for example, preparing reactor assemblies of various specifications by appropriately combining the inner coil portion and the outer coil portion in which the winding cross-sectional area, the number of turns, the axial length of the coil, etc. are changed. The obtained reactor assembly can be obtained by measuring the leakage inductance when the center positions of the inner coil and the outer coil are relatively shifted, and obtaining the relationship between the shift amount l and the leakage inductance.

  In the inner coils 11a, 11b and the outer coils 12a, 12b whose center positions are relatively shifted, the end 11e of the winding 11w that forms the inner coils 11a, 11b and the end of the winding 12w that forms the outer coils 12a, 12b A terminal member is attached to each of 12e, and one end 11e of winding 11w is connected to one end 12e of winding 12w via a terminal member. Through this step, a combination of the annular core 10, the inner coil portion 11, and the outer coil portion 12 is formed.

Alternatively, an outer coil portion is prepared separately, and outer coils 12a and 12b are arranged in the inner coils 11a and 11b to form concentric coil bodies, and the inner coils 11a and 11b of the concentric coil bodies are respectively formed. The coil winding portions 10c _a and 10c _{b in} which the cylindrical portion 14b of the insulator 14 is disposed may be disposed. And after sandwiching the concentric coil body comprising the coil winding part 10c between the insulator frame-like part 14f and the end core 10e, the outer coils 12a, 12b are shifted, or the outer coils 12a, An assembly can be formed by shifting 12b and sandwiching it between the frame-like portion 14f of the insulator 14 and the end core 10e. In order to prevent the end 11e of the winding 11w that forms the inner coils 11a and 11b from interfering when the outer coil portion 12 is assembled, for example, it extends in the axial direction of the inner coils 11a and 11b, and the inner coils 11a and 11b It is preferable that the end 11e does not protrude from the outer periphery of the turn. Then, after the axial positions of the inner coils 11a and 11b and the outer coils 12a and 12b are relatively shifted, the winding 11w is easily attached so that the terminal member can be easily attached and connected to the outer coil. The end portion 11e may be appropriately bent. Alternatively, when the outer coils 12a and 12b are assembled to the outer peripheries of the inner coils 11a and 11b, the outer coils 12a and 12b may be slightly deformed and assembled, and then the outer coils 12a and 12b may be reshaped.

  The obtained combination is housed in a case and filled with potting resin, or the outer periphery of the combination is covered with a resin coating portion. The reactor assembly 1A is assembled by the above process.

[Test example]
In the outer coil and the inner coil, the leakage inductance when the shift amount l of the center position in the axial direction was changed was obtained by simulation.

  In this test, reactor assembly 1B in a state where the axial center position of inner coil 11a (11b) and the axial center position of outer coil 12a (12b) are aligned as shown in FIG. The amount of deviation l = 0 (mm), and the leakage inductance when the amount of deviation l was changed was obtained. More specifically, both outer coils of the outer coil portion are 10 turns, both inner coils of the inner coil portion are 60 turns, and a current is supplied only to the outer coil portion in a state where a pair of inner coils forming the inner coil portion is short-circuited. Leakage inductance was obtained when 1A was applied. The results are shown in Table 1.

  As shown in Table 1, in the reactor assembly in which the inner coil and the outer coil are arranged concentrically, it can be seen that the leakage inductance can be changed by relatively shifting the axial center position of both coils. That is, it can be seen that a desired leakage inductance can be obtained by adjusting the shift amount l. Therefore, by appropriately shifting the axial center position between the inner coil and the outer coil, it is expected that it is possible to meet the demand to obtain a reactor that satisfies a desired resonance frequency and that is small in size.

[effect]
When the reactor assembly 1A is assembled as a component part of a bidirectional DC-DC converter, the reactor assembly 1A includes the inner coil portion 11, so that the boost operation and the step-down operation can be performed, and the outer coil portion 12 is provided. Since soft switching can be performed in the step-up / step-down operation, a loss associated with the switching operation can be reduced. In addition, the reactor assembly 1A includes an inner coil 11a, 11b of the inner coil portion 11 and an outer coil 12a, 12b of the outer coil portion 12, which are coil winding portions 10c _a , 10c _{b of the} annular core 10. Are arranged concentrically, when the resonance coil is arranged in the end core 10e, or when the resonance reactor and the smoothing reactor are separate members, the vertically arranged structure shown in FIG. Compared to the reactor assembly, it is small.

  In addition, the reactor assembly 1A has a predetermined leakage inductance obtained by relatively shifting the axial center position between the inner coil 11a (11b) and the outer coil 12a (12b). For example, it can be used for the inductor Lr for soft switching. Therefore, the reactor assembly 1A is configured to include the inductor Lr, so that it is smaller than the reactor assembly including the inductor Lr as a separate member and further reduces the loss in soft switching. be able to. In addition, the reactor assembly 1A is a concentric arrangement of at least a part of the inner coil 11a (11b) and the outer coil 12a (12b), so that the reactor assembly having a vertically arranged structure shown in FIG. Compared with the body, the installation area is small, the leakage inductance is small, and soft switching can be performed well.

In addition, in the reactor assembly 1A, since the inner coil portion 11 is formed of a covered rectangular wire, the space factor of the coil can be increased, and thus the axial length of the inner coils 11a and 11b can be shortened. And since the axial length of the outer coil 12a (12b) is shorter than the axial length of the inner coil 11a (11b), one end face of the outer coils 12a, 12b protrudes from the inner coils 11a, 11b. Even in the configuration, the length of the coil winding portions 10c _a and 10c _b (the length in the axial direction of the coil) can be shortened, and the reactor assembly 1A is small. Furthermore, the reactor assembly 1A has excellent insulation properties because the outer coil portion 12 is formed of a covered electric wire, so that sufficient insulation is ensured between the inner coil 11a (11b) and the outer coil 12a (12b). can do. In addition, the reactor assembly 1A can be reduced in size by the amount of the insulating material because no additional insulating material is interposed between the coils 11a, 12a (11b, 12b) arranged concentrically as shown in FIG. The number of parts can be reduced. Further, by using a covered electric wire for the outer coil portion 12, the outer coil can be easily formed on the outer periphery of the inner coil by hand winding or the like.

(Embodiment 2: Inner coil portion and outer coil portion-covered electric wire)
In the reactor assembly 1A of the first embodiment, the configuration in which the winding 11w of the inner coil portion 11 is a covered rectangular wire and the winding 12w of the outer coil portion 12 is a covered electric wire has been described. It is good also considering the coil | winding of both coil parts as a covered electric wire. In this case, since the inner coil and the outer coil arranged concentrically can be sufficiently insulated by the insulating coating layer of the covered electric wire, it is not necessary to interpose an insulating material separately. Moreover, the coil arrange | positioned concentrically by manual winding as mentioned above can be easily formed by utilizing a covered electric wire.

(Embodiment 3: Inner coil part and outer coil part-covered rectangular wire)
Or it is good also considering the coil | winding of both coil parts as a covering rectangular wire. In this case, since a coil having high shape retention is obtained, it is easy to move one coil when moving it in order to shift the axial center position between the inner coil and the outer coil. Moreover, when it is set as an edgewise coil, it is easy to make it a coil with a high space factor. Furthermore, when directly connecting the ends of the windings of both coil portions by welding or the like, a sufficient contact area (typically, a welding area) can be secured, and the connected end portions can be secured. Since one terminal member can be attached in common, the number of terminal members and the attachment process can be reduced. Further, when the amount of current flowing through one coil part (for example, the outer coil part) is relatively small, the cross-sectional area of the winding conductor (in this case, a rectangular wire) that forms this coil part may be small. Therefore, when the width of the covered rectangular wire constituting the outer coil portion is made equal to the width of the covered rectangular wire constituting the inner coil portion, the coated rectangular wire constituting the outer coil portion can be used with a small thickness. . A sufficient contact area can be ensured because the coated rectangular wires constituting each coil portion have the same width.

  When the windings of both coil portions are covered rectangular wires, the end portions of the windings forming the inner coil portion may interfere with each other, and it may be difficult to dispose the outer coil on the outer periphery of the inner coil. Therefore, for example, before assembling the outer coil portion to the inner coil portion, the end portion of the winding forming the inner coil portion may be extended in the axial direction of the inner coil as described above.

Moreover, when the winding of both coil parts is a covered rectangular wire, when both coil parts are continuous coils which have a winding back part, there exists a possibility that it may be difficult to arrange | position an outer coil on the outer periphery of an inner coil. Therefore, for example, the configuration may be such that the winding portion of the outer coil portion is slightly raised outward of the outer coil. Alternatively, when both coil portions are formed by covered rectangular wires, as shown in FIG. 4 (B), at least one coil portion (inner coil portion 11 is shown in FIG. If the inner coils 11a and 11b constituting the coil are joined coils formed by different windings, it is easy to dispose the outer coil on the outer periphery of the inner coil. One end portions 11e _a and 11e _b of the windings 11w of the inner coils 11a and 11b may be appropriately connected by welding or the like. For connection of the end portions 11e _a and 11e _b , a plate material for connection may be used separately. However, if the end portions 11e _a and 11e _b are shaped as close as possible and directly joined, Locations and bonding processes can be reduced. The connecting operation between the inner coils 11a and 11b is facilitated by arranging the outer coils 12a and 12b on the outer circumferences of the inner coils 11a and 11b and appropriately shifting them in the axial direction.

  In Embodiments 1 and 2, at least one of the coil portions may be a joined coil in which each coil constituting the coil portion is formed by a separate winding, as shown in FIG. it can. However, when using a covered electric wire for the winding as in the second embodiment, a terminal member is connected to each end of the winding of each coil included in each coil portion, and the coils in the coil portion are connected to each other. It is good to connect via a terminal member.

  In addition, when the windings of both coil portions are coated rectangular wires, in order to improve the insulation between the inner coil and the outer coil arranged concentrically, insulating paper 14B (FIG. 5 (A) described later) Or an insulating member such as a cylindrical bobbin 14C (FIG. 5B described later) made of an insulating material can be interposed. Since the insulating paper 14B is relatively thin, the thickness of the coils arranged concentrically in the stacking direction is not excessively increased, and a small reactor assembly can be obtained. Further, since the insulating paper 14B is relatively inexpensive, the material cost can be reduced. On the other hand, for the cylindrical bobbin 14C, the same material as the constituent material of the insulator 14 described above can be used, and an appropriate shape and thickness may be selected. Further, if the cylindrical bobbin 14C has a configuration in which divided pieces are combined like the cylindrical portion 14b of the insulator 14 described above (FIG. 6 to be described later), it is easy to arrange the cylindrical bobbin 14C on the outer periphery of the inner coil. In particular, if a coil positioning portion (for example, a protrusion or a groove) of at least one coil portion is provided on the bobbin 14C, the coil can be easily positioned with respect to the bobbin 14C and the coil can be easily arranged. In the first and second embodiments, the insulating paper 14B and the bobbin 14C can be provided.

  In addition, when the winding of the outer coil portion is a covered rectangular wire, each outer coil can be a flatwise coil in which the covered rectangular wire is flatwise wound. In this case, the height of the outer coil (size in the direction orthogonal to both the axial direction of the coil and the parallel direction of the pair of coils) and the width of the outer coil (size in the parallel direction of the pair of coils) are reduced. Therefore, it is possible to contribute to downsizing of the reactor assembly. Also, by making the number of turns smaller than that of the inner coil, the axial length of the outer coil can be reduced, and the coil winding portion is not excessively lengthened, and a small reactor assembly is obtained. Can do.

(Embodiment 4: covered round wire)
Alternatively, as the winding 13w, a coated round wire having an enamel coating (insulating coating layer) 13i on the outer periphery of a conductor 13c made of a copper round wire as shown in FIG. 3 (C) may be used. The coated round wire provides a coil having a higher space factor than the coated electric wire and is softer than the coated electric wire, so that it can be easily wound by hand.

  Instead of the covered rectangular wire constituting the inner coil portion 11 of the first embodiment, a covered round wire may be used, the windings of both the coil portions 11 and 12 may be covered round wires, The coil part may be constituted by a covered rectangular wire or a covered electric wire, and the other coil part may be constituted by a covered round wire. When using only a covered round wire or when using a covered round wire and a covered rectangular wire, that is, when not using a covered electric wire as shown in FIG. 3 (B), the reactor assembly 1C shown in FIG. Insulating paper 14B may be disposed between the inner coils 11a, 11b of the inner coil portion 11 and the outer coils 13a, 13b of the outer coil portion 12C arranged concentrically as shown in FIG. 5 (B), FIG. When the cylindrical bobbin 14C is disposed between the inner coils 11a, 11b of the inner coil portion 11 and the outer coils 13a, 13b of the outer coil portion 12C arranged concentrically as in the reactor assembly 1D shown in FIG. Increases insulation.

(Embodiment 5: Sheet wire)
Alternatively, a sheet-like wire having an insulating coating layer (thickness 0.2 mm, polyimide) on the surface of a copper foil conductor (0.1 mm × 1.0 mm) may be used as the winding. The sheet-like wire has a smaller conductor cross-sectional area and a smaller thickness than the above-described coated rectangular wire or the like. Therefore, by using the sheet-like wire, the height of the reactor assembly (size in the direction orthogonal to the axial direction of the coil) can be reduced, which can contribute to downsizing of the reactor assembly. In particular, when the amount of current flowing through the outer coil portion during use is small, such as when used for a resonance reactor, this sheet-shaped wire can be used as a winding forming the outer coil portion.

(Embodiment 6: Material of winding conductor)
In the above-described embodiment, the conductors 11c, 12c, 13c of the windings 11w, 12w, 13w and the sheet-like wire conductor are made of copper. When used as a reactor for resonance, etc., when the amount of current flowing through the outer coil part is small when in use, the conductor of the winding constituting the outer coil part is made of aluminum or aluminum alloy having a lower conductivity than copper May be used. By using a winding whose conductor is made of aluminum or an alloy thereof, it is possible to contribute to weight reduction of the reactor assembly.

(Embodiment 7: Joining of winding ends)
In the reactor assembly 1A of the first embodiment, the terminal member is attached to each of both ends 11e of the winding 11w of the inner coil portion 11 and both ends 12e of the winding 12w of the outer coil portion 12, that is, a total of four A configuration including a terminal member has been described. The one end portion 11e of the winding 11w of the inner coil portion 11 and the one end portion 12e of the winding 12w of the outer coil portion 12 may be directly joined. For joining, in addition to welding such as TIG welding, laser welding, and resistance welding, crimping, cold welding, vibration welding, and the like can be used. In particular, when at least one of the winding forming the inner coil portion and the winding forming the outer coil portion is a covered rectangular wire, a sufficient contact area can be secured at the time of joining. By directly joining one end portions of the windings of both coil portions, one terminal member can be used in common, the number of terminal members and the number of attachment steps can be reduced, and workability can be improved. . In this case, a total of three terminal members are provided.

(Modification: Coil shape)
In the reactor assembly according to each of the embodiments described above, leakage inductance is increased by increasing the interval between adjacent turns among the turns forming the outer coil than the interval between adjacent turns among the turns forming the inner coil. Can be reduced. Accordingly, various amounts of leakage inductance can be obtained by adjusting the axial displacement amount l and the interval between turns in combination.

  The above-described embodiment can be appropriately changed without departing from the gist of the present invention, and is not limited to the above-described configuration. For example, the shift amount l can be changed as appropriate.

  The reactor assembly of the present invention can be suitably used as a component of a power conversion device such as a bidirectional soft switching DC-DC converter mounted on a vehicle such as a hybrid vehicle, an electric vehicle, or a fuel cell vehicle. The method for adjusting the leakage inductance of the reactor assembly of the present invention can be used for forming the reactor assembly of the present invention.

1A, 1B, 1C, 1D reactor assembly 10 core 10c, 10c _a , 10c _b Coil winding part
10e End core 10m Magnetic part 11 Inner coil part 11w, 12w, 13w Winding
11a, 11b Inner coil 11c, 13c Conductor 11e, 11e _a , 11e _b , 12e End of winding
11r Winding part 11i, 12i, 13i Insulation coating layer 12,12C Outer coil part
12a, 12b, 13a, 13b Outer coil 12s Wire 12c Stranded wire conductor 14 Insulator
14b Tube 14f Frame 14B Insulating paper 14C Bobbin
L Reactor 100 core 100c _a , 100c _b Coil winding part 100e End core
110,120 Coil part 110a, 110b, 120a, 120b Coil 111 winding

Claims (14)

An annular core having a pair of coil winding portions arranged in parallel and a pair of end cores arranged so as to sandwich both coil winding portions;
An inner coil portion having a pair of inner coils, each of which is formed by winding a winding spirally, and is disposed on the outer periphery of each coil winding portion;
An outer coil portion having a pair of outer coils arranged coaxially on the outer circumference of each inner coil, the winding being spirally wound,
One end of the winding constituting the one inner coil and one end of the winding constituting the one outer coil are joined,
The reactor assembly, wherein an axial center position of the outer coil and an axial center position of the inner coil are shifted in the axial direction.   At least one of the winding constituting the inner coil portion and the winding constituting the outer coil portion is a stranded conductor formed by twisting a plurality of strands, and an insulating coating layer provided on the outer periphery of the stranded conductor The reactor assembly according to claim 1, wherein the reactor assembly is a covered electric wire.   One of the winding constituting the inner coil portion and the winding constituting the outer coil portion is the covered electric wire, and the other is provided on a conductor made of a flat wire or a round wire and on the outer periphery of the conductor. 3. The reactor assembly according to claim 2, wherein the reactor assembly is a coated flat wire or a coated round wire including an insulating coating layer. The winding constituting the inner coil portion and the winding constituting the outer coil portion are a covered rectangular wire or a conductor comprising a flat wire or a round wire and an insulating coating layer provided on the outer periphery of the conductor. Covered round wire,
2. The reactor assembly according to claim 1, wherein an insulating material is interposed between the inner coil and the outer coil disposed on the outer periphery thereof. In at least one of the inner coil portion and the outer coil portion, each coil constituting the coil portion is a covered rectangular wire having a conductor made of a rectangular wire and an insulating coating layer provided on the outer periphery of the conductor. Is an edgewise coil that is wound edgewise,
5. The reactor assembly according to any one of claims 1 to 4, wherein the coil portion is formed by welding one end portions of each covered rectangular wire constituting each coil. In at least one of the inner coil portion and the outer coil portion, each coil constituting the coil portion is a covered rectangular wire having a conductor made of a rectangular wire and an insulating coating layer provided on the outer periphery of the conductor. Is an edgewise coil that is wound edgewise,
The coil part is composed of one continuous covered rectangular wire, and both coils constituting the coil part are connected to each other via a winding part formed by folding a part of the covered rectangular wire. The reactor assembly according to any one of claims 1 to 4, wherein:   The reactor according to any one of claims 1 to 6, wherein an axial length of one of the inner coil and the outer coil is shorter than an axial length of the other coil. Aggregation.   8. The reactor assembly according to claim 1, further comprising a resin coating portion that covers an outer periphery of a combination of the core, the inner coil portion, and the outer coil portion.   9. The reactor assembly according to any one of claims 1 to 8, wherein a conductor of the winding wire constituting the outer coil portion is made of aluminum or an aluminum alloy.   2. Each of the outer coils is a flatwise coil obtained by flatwise winding a coated flat wire including a conductor made of a flat wire and an insulating coating layer provided on the outer periphery of the conductor. The reactor assembly according to any one of? 9. In at least one of the inner coil portion and the outer coil portion, each coil constituting the coil portion is a covered rectangular wire having a conductor made of a rectangular wire and an insulating coating layer provided on the outer periphery of the conductor. Winding
11. The reactor assembly according to claim 1, wherein one end portion of the inner coil and one end portion of the outer coil are joined by welding.   10. The reactor assembly according to claim 1, wherein the winding constituting the outer coil portion is a sheet-like wire material in which an insulating material is laminated on a surface of a foil-like conductor. .   13. The reactor assembly according to any one of claims 1 to 12, wherein the reactor assembly is used as a component part of a bidirectional soft switching converter. An inner coil formed by spirally winding the winding is disposed on the outer periphery of the annular core, and an outer coil formed by spirally winding the winding on the outer periphery of the inner coil is disposed coaxially with the inner coil.
A method of adjusting a leakage inductance of a reactor assembly, wherein the axial center position of the outer coil and the axial center position of the inner coil are relatively shifted so that a predetermined leakage inductance is obtained.

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