WO2015087129A1 - Power converter - Google Patents

Power converter Download PDF

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Publication number
WO2015087129A1
WO2015087129A1 PCT/IB2014/002693 IB2014002693W WO2015087129A1 WO 2015087129 A1 WO2015087129 A1 WO 2015087129A1 IB 2014002693 W IB2014002693 W IB 2014002693W WO 2015087129 A1 WO2015087129 A1 WO 2015087129A1
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WO
WIPO (PCT)
Prior art keywords
coils
core
reactor
cooler
power converter
Prior art date
Application number
PCT/IB2014/002693
Other languages
French (fr)
Inventor
Mao NOBUSAKA
Original Assignee
Toyota Jidosha Kabushiki Kaisha
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Toyota Jidosha Kabushiki Kaisha filed Critical Toyota Jidosha Kabushiki Kaisha
Publication of WO2015087129A1 publication Critical patent/WO2015087129A1/en

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Classifications

    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K7/00—Constructional details common to different types of electric apparatus
    • H05K7/20—Modifications to facilitate cooling, ventilating, or heating
    • H05K7/2089—Modifications to facilitate cooling, ventilating, or heating for power electronics, e.g. for inverters for controlling motor
    • H05K7/20927—Liquid coolant without phase change
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/08—Cooling; Ventilating
    • H01F27/10—Liquid cooling
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/24—Magnetic cores
    • H01F27/255—Magnetic cores made from particles
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/40—Structural association with built-in electric component, e.g. fuse
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F37/00—Fixed inductances not covered by group H01F17/00
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L23/00—Details of semiconductor or other solid state devices
    • H01L23/34—Arrangements for cooling, heating, ventilating or temperature compensation ; Temperature sensing arrangements
    • H01L23/40—Mountings or securing means for detachable cooling or heating arrangements ; fixed by friction, plugs or springs
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L23/00—Details of semiconductor or other solid state devices
    • H01L23/34—Arrangements for cooling, heating, ventilating or temperature compensation ; Temperature sensing arrangements
    • H01L23/40—Mountings or securing means for detachable cooling or heating arrangements ; fixed by friction, plugs or springs
    • H01L23/4006—Mountings or securing means for detachable cooling or heating arrangements ; fixed by friction, plugs or springs with bolts or screws
    • H01L23/4012—Mountings or securing means for detachable cooling or heating arrangements ; fixed by friction, plugs or springs with bolts or screws for stacked arrangements of a plurality of semiconductor devices
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L23/00—Details of semiconductor or other solid state devices
    • H01L23/34—Arrangements for cooling, heating, ventilating or temperature compensation ; Temperature sensing arrangements
    • H01L23/46—Arrangements for cooling, heating, ventilating or temperature compensation ; Temperature sensing arrangements involving the transfer of heat by flowing fluids
    • H01L23/473—Arrangements for cooling, heating, ventilating or temperature compensation ; Temperature sensing arrangements involving the transfer of heat by flowing fluids by flowing liquids
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L23/00—Details of semiconductor or other solid state devices
    • H01L23/58—Structural electrical arrangements for semiconductor devices not otherwise provided for, e.g. in combination with batteries
    • H01L23/64—Impedance arrangements
    • H01L23/645—Inductive arrangements
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L25/00—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof
    • H01L25/03—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof all the devices being of a type provided for in the same subgroup of groups H01L27/00 - H01L33/00, or in a single subclass of H10K, H10N, e.g. assemblies of rectifier diodes
    • H01L25/04—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof all the devices being of a type provided for in the same subgroup of groups H01L27/00 - H01L33/00, or in a single subclass of H10K, H10N, e.g. assemblies of rectifier diodes the devices not having separate containers
    • H01L25/065—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof all the devices being of a type provided for in the same subgroup of groups H01L27/00 - H01L33/00, or in a single subclass of H10K, H10N, e.g. assemblies of rectifier diodes the devices not having separate containers the devices being of a type provided for in group H01L27/00
    • H01L25/0652—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof all the devices being of a type provided for in the same subgroup of groups H01L27/00 - H01L33/00, or in a single subclass of H10K, H10N, e.g. assemblies of rectifier diodes the devices not having separate containers the devices being of a type provided for in group H01L27/00 the devices being arranged next and on each other, i.e. mixed assemblies
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L25/00—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof
    • H01L25/03—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof all the devices being of a type provided for in the same subgroup of groups H01L27/00 - H01L33/00, or in a single subclass of H10K, H10N, e.g. assemblies of rectifier diodes
    • H01L25/10—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof all the devices being of a type provided for in the same subgroup of groups H01L27/00 - H01L33/00, or in a single subclass of H10K, H10N, e.g. assemblies of rectifier diodes the devices having separate containers
    • H01L25/11—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof all the devices being of a type provided for in the same subgroup of groups H01L27/00 - H01L33/00, or in a single subclass of H10K, H10N, e.g. assemblies of rectifier diodes the devices having separate containers the devices being of a type provided for in group H01L29/00
    • H01L25/117—Stacked arrangements of devices
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K7/00—Constructional details common to different types of electric apparatus
    • H05K7/14—Mounting supporting structure in casing or on frame or rack
    • H05K7/1422—Printed circuit boards receptacles, e.g. stacked structures, electronic circuit modules or box like frames
    • H05K7/1427—Housings
    • H05K7/1432—Housings specially adapted for power drive units or power converters
    • H05K7/14329—Housings specially adapted for power drive units or power converters specially adapted for the configuration of power bus bars
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/0001—Technical content checked by a classifier
    • H01L2924/0002—Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/10—Details of semiconductor or other solid state devices to be connected
    • H01L2924/11—Device type
    • H01L2924/13—Discrete devices, e.g. 3 terminal devices
    • H01L2924/1304—Transistor
    • H01L2924/1305—Bipolar Junction Transistor [BJT]
    • H01L2924/13055—Insulated gate bipolar transistor [IGBT]

Definitions

  • a technique described in the present specification relates to a power converter in which a reactor is stacked on a laminated unit.
  • the laminated unit is configured such that a plurality of coolers and a plurality of semiconductor modules are laminated.
  • the "reactor” is a passive element using a coil, and is also referred to as an "inductor.”
  • An electric vehicle including a hybrid vehicle is equipped with a power converter that converts output power of a battery into alternating current and supplies it to a drive motor.
  • the power converter may include a voltage converter circuit that boosts a voltage of the battery, as well as an inverter circuit that converts direct current into alternating current.
  • These circuits have many switching elements and a reactor. Since heavy-current flows through such a device group (the switching elements and the reactor), a heat generation amount is also large. On that account, the device group is cooled by a cooler. An exemplary unit that cools such a device group collectively is described in Japanese Patent Application Publication No. 2012-5259 (JP 2012-5259 A).
  • the laminated unit is configured such that a plurality of flat semiconductor modules in each of which a switching element is sealed, and a plurality of flat coolers are laminated. Further, the reactor is attached to an end of the laminated unit so as to make contact with the cooler. That is, the plurality of flat coolers cools the semiconductor modules and the reactor.
  • the laminated unit is able to secure a large contact area between the semiconductor modules or the reactor and the coolers, and achieves high coolability while being compact.
  • the present specification provides a balanced power converter that avoids upsizing of a device and considers both measures to the leakage magnetic flux and cooling performance.
  • a power converter described in the present invention includes a laminated unit and a reactor.
  • the laminated unit is configured such that a plurality of coolers and a plurality of semiconductor modules are laminated.
  • the reactor is stacked on the laminated unit.
  • the reactor includes a plurality of coils, and a core. Coils adjacent to each other are wound in reverse directions to each other and are connected in series. The coils adjacent to each other are arranged side by side in a radial direction of the coils.
  • the core is configured to cover surroundings of the coils and includes window portion through which outer peripheral surface of the coil are exposed. The outer peripheral surface of the coil makes contact with the cooler through the window portion.
  • a balanced power converter that considers downsizing of a device, measures to a leakage magnetic flux, and cooling performance can be achieved.
  • FIG. 1 is a perspective view of a power converter of a first embodiment
  • FIG. 2 is a schematic sectional view taken along a direction of arrows II in FIG. 1;
  • FIG. 3 is a schematic partial sectional view taken along a direction of arrows III in FIG 2;
  • FIG- 4 is a perspective view of a reactor in which coils are formed by edgewise - winding
  • FIG. 5 is a perspective view of a reactor in which coils are formed by flatwise winding
  • FIG. 6 is a perspective view of a power converter of a second embodiment
  • FIG. 7 is a partial sectional view around a reactor of the power converter of the second embodiment when taken along an XY plane;
  • FIG. 8 is a view illustrating a core in gray in FIG. 4.
  • a power converter described, in the present specification includes a laminated unit and a reactor.
  • the laminated unit is configured such that a plurality of flat coolers and a plurality of flat semiconductor modules are laminated alternately.
  • the reactor is stacked adjacent to the cooler of the laminated unit. That is, the reactor is also cooled by the cooler. Note that the plurality of semiconductor modules and the plurality of coolers may be laminated alternately, but some of the semiconductor modules may be laminated successively.
  • the reactor includes a plurality of coils and a core covering surroundings of the coils (inside and outside of the coils). Coils adjacent to each other are wound in reverse directions to each other and connected in series, and further arranged side by side in a radial direction thereof. Note that “the coils are wound in reverse directions to each other” indicates that current flowing directions are opposite to each other when the coils are viewed from a coil axis direction.
  • the core includes window portions, and outer peripheral surfaces of the coils are exposed through the window portions. The exposed outer peripheral surfaces of the coils are opposed to the cooler so as to make contact with the cooler.
  • the main loop is a loop formed from large part of the magnetic fluxes generated from the coils.
  • the window portions are provided in places that avoid the main loop of the magnetic fluxes. That is, outer peripheral surfaces of those parts of the coils which are placed outside the main loop of the magnetic fluxes are exposed through the window portions.
  • the window portions By providing the window portions as such, a leakage magnetic flux can be reduced and a loss of the reactor can be restrained. Further, since the exposed outer peripheral surfaces of the coils make contact with the cooler, the reactor (that is, the coils) is cooled efficiently via the outer peripheral surfaces. Further, since the reactor is stacked on the laminated unit and is cooled off hereby, the power converter is not upsized. Accordingly, it is possible to achieve measures to the leakage magnetic. flux and improvement of cooling performance in a good balance while avoiding upsizing of the device, Note that the exposed outer peripheral surfaces of the coils may make contact with the cooler via a heat dissipation sheet.
  • the reactor be stacked on an end of the laminated unit in its laminating direction.
  • the window portions of the core are provided only on a core side surface opposed to the cooler, so that a leakage magnetic flux is reduced on core side surfaces that do not make contact with the cooler.
  • a loss of the reactor can be reduced. Note that an appearance of the reactor in which surroundings of the coils except the window portions are covered with a resin core is often formed in a rectangular solid.
  • a thickness of that part of the core which is placed outside the coils in a coil axis direction may be thicker than a thickness of that part of the core which is placed outside the coils in a radial direction of the coils. That part of the core which is placed outside the coils in the coil axis direction corresponds to a path of the main loop described above. By thickening that part of the core which corresponds to the path of the main loop, the leakage of the magnetic fluxes is restrained. As a result, the loss of the reactor can be further restrained.
  • the coils may be formed by winding a flat wire in an edgewise manner, or the coils may be formed by winding a flat wire in a flatwise manner.
  • a narrow side surface of the flat wire in each pitch becomes the outer peripheral surface exposed from the window portion of the core. That is, narrow side surfaces of the flat wire in respective pitches are opposed to the cooler.
  • an area of the outer peripheral surface of the coil is increased as the number of turns of winding is larger, so that a heat transfer amount from the coil to the cooler increases.
  • the flat wire in each pitch dissipates heat generated from the coil to the cooler.
  • edges placed on an inner side of the coil and pitches placed on . an outer side of the coil are both cooled generally uniformly.
  • the edgewise winding indicates winding in which a flat wire is wound so that wide surfaces of the flat wire are superimposed on one another toward the coil axis direction. That is, the edgewise winding is winding in which flat surfaces of the flat wire are stacked in the coil axis direction.
  • the coil is formed by winding a flat wire in a flatwise manner
  • an outermost wide surface of the flat wire corresponds to the outer peripheral surface exposed from the window portion of the core. That is, the outermost flat side surface (wide side surface) of the flat wire is opposed to the cooler, so that the heat of the coil is transmitted to the cooler.
  • the cooling efficiency with respect to the coil, namely, the reactor improves.
  • the flatwise winding indicates winding in which a flat wire is wound so that wide surfaces of the flat wire are superimposed on one another such that the wide surfaces face the radial direction of the coil. That is, the flatwise winding is winding in which the wide surfaces of the flat wire are stacked in the radial direction of the coil.
  • FIG. 1 is a perspective view of the power converter 2.
  • the power converter 2 is a device provided in a hybrid vehicle or an electric vehicle so as to boost direct-current power of a battery and to convert it into alternating-current power having a frequency suitable for driving of a drive motor (an induction motor, a PM motor, or the like).
  • the power converter 2 typically includes a voltage converter circuit and an inverter circuit. These circuits use many power semiconductor elements, and these elements are housed in a plurality of flat semiconductor modules 12 dispersedly.
  • Each of the semiconductor modules 12 is obtained by molding one or more power semiconductor elements with resin.
  • the power semiconductor element is typically an IGBT (Insulated Gate Bipolar Transistor).
  • IGBT Insulated Gate Bipolar Transistor
  • FIG. l * four flat semiconductor modules 12 are illustrated, but a reference sign 12 is assigned to only one of them and the reference sign is omitted in terms of the other semiconductor modules.
  • the semiconductor module 12 houses therein a power semiconductor element as such. Further, heavy-current flows through the semiconductor module 12, so its heat generation amount is large.
  • the laminated unit 10 is configured such that a plurality of flat semiconductor modules 12 is laminated alternately with a plurality of flat coolers 11.
  • the laminated unit 10 is housed in a housing 3.
  • a reactor 20 is also stacked on the laminated unit 10 as weir as the semiconductor modules 12.
  • the reactor 20 is stacked on an end of the laminated unit of the semiconductor modules 12 and the coolers 11 so as to make contact with one of the coolers 11.
  • the reactor 20 is an element used for the voltage converter circuit, and heavy-current also flows there through.
  • the reactor 20 has a large heat generation amount, so that cooling by the cooler 11 is necessary.
  • the reactor 20 is configured such that one side surface thereof makes contact with the cooler 11 via an insulating heat dissipation plate 18. The reason for this will be described later.
  • a refrigerant supply pipe 14 ⁇ nd a refrigerant discharge pipe 15 are connected to an outermost cooler 11 among the plurality of coolers 11.
  • a flow path through which refrigerant flows is formed inside the coolers 11, so refrigerant (e.g., LLC (Long Life Coolant)) supplied from the refrigerant supply pipe 14 spreads to all the coolers 11 through the connecting pipe 13 provided on a side closer to the refrigerant supply pipe 14.
  • refrigerant e.g., LLC (Long Life Coolant) supplied from the refrigerant supply pipe 14 spreads to all the coolers 11 through the connecting pipe 13 provided on a side closer to the refrigerant supply pipe 14.
  • the refrigerant passing through each of the coolers 11 cools the semiconductor modules 12 and the reactor 20.
  • the refrigerant that absorbs heat from the semiconductor modules 12 and the like then passes through each of the coolers 11, and then discharged out of the refrigerant discharge pipe 15 through the connecting pipe 13 provided on an opposite side.
  • the laminated unit 10 in order to increase cooling efficiency by the coolers 11, the laminated unit 10 is pressurized in its laminating direction (in an X-axis direction in a coordinate system illustrated in FIG. 1). That is, a leaf spring 5 supported by support pillars 4 of the housing 3 makes pressure contact with one end side of the laminated unit 10 so as to press the other end side (the reactor 20) of the laminated unit 10 against an inner wall of the housing 3, and thus, the laminated unit 10 is held in a sandwiched manner within the housing 3.
  • a degree of adhesion between the semiconductor modules 12 and the coolers 11 and a degree of adhesion between the reactor 20 and the cooler 11 are raised, so heat transfer performance to the coolers 11 improves.
  • downsizing of the power converter 2 is achieved by employing the configuration to cool the semiconductor modules 12 and the reactor 20 by the laminated unit 10.
  • a reference sign 7 indicates a high-capacity smoothing capacitor for use in the inverter circuit and the voltage converter circuit, and the power converter 2 is configured such that the capacitors 7 are also housed in the housing 3.
  • the power converter 2 further includes a control board for controlling the voltage converter 5 circuit and the inverter circuit in addition to these devices, but FIG. 1 does not illustrate the control board and a cover of the housing 3.
  • FIG. 2 is a schematic sectional view of the laminated unit 10.
  • the sectional view schematically illustrates a section of the reactor 20 along a direction of arrows II when the 10 laminated unit 10 is taken along an alternate long and short dash line shown in FIG. 1.
  • FIG. 3 is a schematic partial sectional view of the laminated unit 10.
  • the sectional view schematically illustrates a section of the reactor 20 and a plane of the laminated unit 10 around the reactor 20 along a direction of arrows III when the reactor 20 is taken along an alternate long and short dash line shown in FIG. 2.
  • FIG. 4 is a 15 perspective view of the reactor 20. In order to assist understanding, a case 25 is cut at a center in an up-down direction and a top half thereof is omitted in FIG. 4.
  • the reactor 20 has an appearance formed in a rectangular, solid.
  • the reactor 20 is constituted by two coils 21, 22, a core 24, and the case 25.
  • the coils 21, 22 are winding coils formed by winding a flat wire 23 in an edgewise manner. That is, in the 20 coils 21, 22, the flat wire 23 is wound so that wide side surfaces of the flat wire 23 are stacked so as to face a direction of a coil axis CL (a Z-axis direction in a coordinate system ' illustrated in FIGS. 2 to 4).
  • the coils 21, 22 are wound so as to form a generally square shape when viewed from the direction of the coil axis CL.
  • the coils 21, 22 are wound in reverse directions to each other and arranged side by side in a 25 radial direction thereof so as to be connected in series.
  • the coils 21, 22 are housed in the case 25, and their surroundings are covered with the core 24 except some part thereof.
  • the coils are wound in reverse directions to each other
  • the coil 21 and the coil 22 are made from one flat wire.
  • a reference sign 23s indicates an initial point of the winding
  • a reference sign 23e indicates an end point of the winding.
  • the coil 21 and the coil 22 are both wound clockwise toward a positive direction of the Z-axis. However, when viewed from the initial point 23s toward the end point 23e of the winding, the coil 21 is wound clockwise, and the coil 22 is wound counterclockwise, and thus, they are wound in reverse directions to each other.
  • the direction from the initial point 23s toward the end point 23e of the winding indicates a direction where current flows.
  • the coils are wound in reverse directions to each other indicates that winding directions are reverse to each other in the direction where current flows.
  • the coils 21 and 22 are wound so that respective magnetic fluxes caused in respective coils at the time when current is applied thereto are directed toward reverse directions.
  • the core 24 is obtained by hardening resin mixed with soft magnetic material particles. Powdery resin (resin powder including soft magnetic material particles) before hardening is filled into the case 25, so as to form the core 24 covering generally entire surroundings of the coils 21, 22 (inside and outside of the coils). In other words, the core 24 molds the coils 21, 22 with resin, . In the figure, the core 24 corresponds to a whole internal space of the case 25. However, in order to easily see the coils inside the core 24 and broken lines (broken lines indicating magnetic fluxes) for description, only a contour of the core 24 is illustrated by an alterriate long and two short dashes line. See FIG. 8 in which the core 24 in FIG. 4 is illustrated in gray. FIG.
  • FIG. 8 is the same as FIG. 4 except that the core 24 is illustrated in gray.
  • the core 24 of the present embodiment is formed in a rectangular solid as a whole, and window portions 24b through which outer peripheral surfaces 21a, 22a of the coils 21, 22 are exposed outside are formed on one side surface 24a thereof. See FIG. 8 in particular about the window portions 24b.
  • FIG. 8 it is shown well that the outer peripheral surfaces 21a, 22a of the coils 21, 22 are exposed from the window portions 24b provided in the core 24 in gray. That is, when the core 24 is viewed from a direction of the coil axis CL, the coils 21, 22 are placed on the one side surface 24a of the core 24 in a biased manner.
  • the outer peripheral surfaces 21a, 22a of the coils 21, 22 are not covered with the core 24, but exposed outside the core 24 (see FIGS. 3, 4).
  • the core 24 is filled in the internal space of the case 25, but FIG. 4 shows the coils 21, 22 without the core 24, in order to easily understand the figure.
  • an arrow indicated by a reference sign 24a indicates a side surface parallel to a YZ plane and placed in a positive direction of the X-axis in the figure, among side surfaces of the core 24 of the rectangular solid.
  • outside of rectangular shapes indicative of the window portions 24b is filled with the core 24, and the coils 21, 22 are not visible from outside except parts inside the rectangular shapes indicative of the window portions 24b.
  • a shape of the core 24 in its short direction is formed unsymmetrically when the core 24 is viewed in terms of the coils 21, 22.
  • the one side surface 24a of the core 24 including the window portions 24b may be formed in a step of forming the core 24 by molding, or may be formed by cutting and grinding after the core 24 is formed by molding.
  • those parts of the core 24 which is removed to form the window portions 24b are conveniently referred to as "cut portions.” ; - . .. . . . . . . .
  • the core 24 is set to have a relatively thin (small) wall thickness (ranges T2 and T3 in FIG 3) in those parts of the core 24 which are placed radially outside . the coils 21, 22, except the cut portions.
  • a thermal resistance is small as ' compared with a case where the wall thickness of the core 24 is thick, heat of the core 24 is easily transmitted to the case 25.
  • the core 24 is set to have a thick wall thickness (ranges Tl shown in FIG. 2) in those parts of the core 24 which are placed outside the coils in the direction of the coil axis CL.
  • the case 25 is made of a metal plate in a box shape of a rectangular solid, and is made of a metallic material, such as aluminum, having high heat conductivity.
  • the case 25 has an opening 25a that is opened generally over one side surface.
  • the one side surface 24a of the core 24 is exposed from the opening 25a, and further, the outer peripheral surfaces 21a, 22a of the coils 21, 22 are exposed outside therefrom.
  • the outer peripheral surfaces 21a, 22a are configured such that narrow side surfaces 23a of respective pitches (respective turns) of the flat wire 23 wound in an edgewise manner are stacked in the direction of the coil axis CL. Note that it is necessary to hold the coils 21, .22 at a predetermined position in the case 25.
  • a support portion for holding the coils 21, 22 may be formed within the case 25. This makes it -easy to position the coils 21, 22 -in the case 25. Note that, on a bottom face of the case 25, through holes or notch portions through which the flat wire 23 led out of respective ends of the coils 21, 22 passes are formed, although not illustrated in FIG. 4.
  • the reactor 20 is configured as such.
  • a part of the outer peripheral surface (the one side surface 24a) of the core 24 is exposed from the opening 25a of the case 25, and parts of the outer peripheral surfaces 21a, 22a of the coils 21, 22 are further exposed from the window portions 24b formed on the one side surface 24a.
  • the exposed outer peripheral surfaces 21a, 22a of the coils 21, 22 are opposed to the cooler 11, so the outer peripheral surfaces 21a, 22a of the coils 21, 22 make contact with the cooler 11.
  • the outer peripheral surfaces 21a, 22a make contact with the cooler 11 includes a case where a heat dissipation seat or the like is sandwiched therebetween. The reason is because the heat dissipation seat can be considered as part of the cooler 11.
  • the coils 21, 22 wound in an edgewise manner are employed for the reactor 20. Accordingly, areas of the outer peripheral surfaces 21a, 22a increase as the number of turns of winding is larger. On that account, heat dissipation effect with respect to the cooler 11 increases along with an increase of the number of turns of winding. Further, respective pitches (respective turns) of the stacked flat wire 23 dissipate heat of the coils 21, 22 to the cooler 11, so that the coils 21, 22 dissipate heat generally uniformly regardless of inside or outside of the coils 21, 22.
  • the coils 21, 22 do not function as a sum of individual small reactors, but the coil 21 and the coil 22 function as one large reactor.
  • the core 24 through which the main loop of the magnetic fluxes MF passes has a large wall thickness (the ranges Tl in FIG. 2) in those parts outside the coils along the coil axis CL, so a leakage magnetic flux of the main loop is Teduced.
  • those cut portions of the core 24 which include the window portions 24b formed on the one side surface 24a of the core 24 are provided at positions that avoid the main loop of the magnetic fluxes MF. Accordingly, even in the configuration in which the core 24 is not provided on the one side surface 24a, the main loop of the magnetic fluxes MF is hard to be affected. That is, the magnetic fluxes MF of the main loop do not leak from the one side surface 24a (the, cut portions) of the core 24, or have little leakage magnetic flux.
  • the heat dissipation plate 18 is provided between the cooler 11 and the reactor 20 (see FIG. 3).
  • the heat dissipation plate 18 is a thin insulating plate made of an insulating material having a high thermal conductive characteristic.
  • the outer peripheral surfaces 21a, 22a of the coils 21, 22 make contact with the heat dissipation plate 18 through the window portions 24b, so heat of the coils 21, 22 is transmitted to the cooler 11.
  • the coils 21, 22 are cooled by the cooler 11.
  • the heat dissipation plate 18 can be omitted.
  • the outer peripheral surfaces 21a, 22a of the coils 21, 22 directly make contact with the cooler 11, so heat generated from the coils 21, 22 is directly transmitted to the cooler 11 and cooling efficiency by the cooler 11 can be raised.
  • the power converter 2 of the present embodiment includes: the laminated unit 10 configured such that the plurality of flat coolers 11 and the plurality of flat semiconductor modules 12 are laminated alternately; and the reactor 20 stacked on an end of the laminated unit 10 in the laminating direction so as to be cooled by the cooler 11.
  • the reactor 20 includes: the plurality of coils 21, 22 configured such that the coils 21, 22 adjacent to each other are wound in reverse directions to each other and are connected in series to each other, the coils 21, 22 being arranged side by side in the radial direction; and the core 24 covering surroundings of the coils 21, 22 (inside and outside of the coils).
  • the core 24 includes the window portions 24b through which the outer peripheral surfaces 21a, 22a of the coils 21, 22 are exposed, and the exposed outer " peripheral surfaces 21a, 22a of the coils 21, 22 are opposed to the cooler 11.
  • the outer - peripheral surfaces 21a, 22a of the coils 21, 22 make contact with the cooler 11. Accordingly, when current is flowed through two coils 21, 22 thus connected, the current flows through the coils 21, 22 in reverse directions to each other.
  • magnetic fluxes MF reverse to each other are caused in the coils 21, 22, so as to form one main loop interlinking with the coils 21, 22.
  • the window portions 24b are provided in places that avoid the main loop of the magnetic fluxes MF, so an interlinkage flux due to a leakage magnetic flux is reduced and a loss of the reactor 20 is restrained. Further, since the exposed outer peripheral surfaces 21a, 22a of the coils 21, 22 are opposed to the cooler 11, the outer peripheral surfaces 21a, 22a make contact with the cooler 11 so as to cool the reactor 20 by dissipating heat generated from the coils 21, 22 to the cooler 11.
  • the reactor 20 is stacked on the laminated unit 10 including the coolers 11 and the semiconductor modules 12 and is cooled hereby, so that the power converter 2 is downsized. Accordingly, a balance between a size (avoidance of upsizing) of the power converter 2, a leakage magnetic flux, and cooling performance is increased.
  • those parts of the core 24 which are placed outside the coils in the direction of the coil axis CL have a large wall thickness. This reduces a leakage magnetic flux in the direction of the coil axis CL.
  • winding coils formed by winding the flat wire 23 in an edgewise manner are employed as. the coils 21, 22.
  • winding coils formed by winding a flat wire in a flatwise manner may be employed. That is, in this modified example, a reactor 30 is configured such that surroundings of coils 31, 32 formed by winding a flat wire 33 in a flatwise manner are covered with a core 24 and housed in a case 25, as illustrated in FIG. 5. The flat .wire 33 is wound so that its wide side surfaces are stacked so as to face a radial direction of the coils 31, 32 (a Y-axis direction in a coordinate system shown in FIG. 5).
  • FIG. 5 is a perspective view of the reactor 30.
  • FIG. 5 a top half of the case 25 is cut similarly to FIG. 4, and further, the core 24 is illustrated by a contour indicated by an alternate long and two short dashes line. Note that the same reference sign is assigned to substantially the same component as in the reactor 20, and a description thereof is omitted. Further, similarly to FIG. 4, the coils 31, 32 are illustrated without the core 24, in order to easily understand the figure. Furthermore, outside of rectangular shapes indicative of window portions 24b is filled with resin of the core 24, so that the coils 31, 32 are not visible from outside except parts inside the rectangular shapes indicative of the window portions 24b.
  • the reactor 30 of the modified example is configured such that the coils 31, 32 are wound in reverse directions to each other and are connected in series.
  • the meaning of "winding in reverse directions" is the same as described above.
  • the coils 31, 32 are housed in the case 25, and their surroundings are covered with the core 24 except some part thereof.
  • outer peripheral surfaces 31a, 32a of the coils 31, 32 are exposed outside from the window portions 24b formed on one side surface 24a of the core 24.
  • the exposed outer peripheral surfaces 31a, 32a of the cails 31, 32 are opposed to the cooler 11, so the outer peripheral surfaces
  • the power converter 2 of the above embodiment or its modified example employs a configuration in which the window portions 24b of the core 24 through which the outer peripheral surfaces 21a, 22a (or the outer peripheral surfaces 31a, 32a) of the coils 21, 22 (or the coils 31, 32) are exposed are provided on the one side surface 24a of the core 24, and no window portion 24b is provided on its opposite side. That is, the cut portions are formed only on the one side surface 24a of the core 24, so that the shape of the core 24 in the short direction (the X-axis direction) is formed unsymmetrically. Note that the coils 21, 22 are covered with the core 24 on the other side surfaces except the one side surface 24a of the core 24. Thus, the window portions 24b are provided only on the one side surface 24a opposed to the cooler 11. Since the core 24 is provided on the opposite side, a magnetic flux to leak is reduced.
  • FIG. 6 is a perspective view of the power converter 2a.
  • FIG. 7 is a partial sectional view of the power converter 2a, taken along an XY plane.
  • FIG. 7 is a partial sectional view- around a reactor 40 in the power converter 2a. Since the reactor 40 has the same configuration as the reactor 20 in the first embodiment, the same reference signs as used in the reactor 20 of the first embodiment are used to indicate respective portions in the reactor.
  • the reactor 20 is stacked on the end of the laminated unit 10. That is, only one side surface of the reactor 20 makes contact- with -the cooler 11-.
  • the reactor 40 is stacked so that coolers 11 are placed on both sides of the reactor 40. Since the coolers 11 make contact with both sides of the reactor 40, cooling effect on the reactor 40 further increases.
  • the power converters 2, 2a of the first, second embodiments employ a configuration in which the window portions 24b of the core 24 through which the outer peripheral surfaces 21a, 22a of the coils 21, 22 are exposed are provided on the one side surface 24a of the core 24, and no window portion 24b is provided on its opposite side.
  • the cut portions are formed only on the one side surface 24a of the core 24, so that- the shape of the core 24 in the short direction (the X-axis direction) is formed unsymmetrically.
  • the window portions 24b are provided only on the one side surface 24a opposed to the cooler 11. Since the core 24 is provided on the opposite side, a magnetic flux to leak is reduced.
  • a leakage magnetic flux is reduced as compared with a case where the window portions 24b are formed on both sides of the core 24 in the short direction, so that a loss of the reactor 40 is further restrained. On that account, a loss of the reactor 20 (or the reactor 40) can be further reduced.
  • the coils 21, 22 can be cooled by the coolers 11 from both sides. Hereby, cooling performance is increased more. Note that, in this configuration, when it is necessary to secure electric insulation to the coolers 11, the reactor 40 makes contact with the coolers 11 via heat dissipation plates 18 provided on both sides of the reactor 40.
  • Such a configuration in which the coils are exposed on two parallel-flat surfaces of the reactor and respective side surfaces of the coils make contact with the coolers can be also realized by the reactor of FIG. 5 in which the coils are wound in a flatwise manner.
  • the reactor 20 (or the reactors 30, 40) is constituted by two coils 21, 22 connected in series (or two coils 31, 32 connected in series), but the reactor may be constituted by multiple coils connected in series.
  • the reactor may be constituted by multiple coils connected in series.
  • three or more coils wound in an edgewise manner or flatwise manner are arranged in a radial direction and are positioned so that winding directions of coils adjacent to each other among them are reverse to each other, and then, all the coils are connected in series to each other.
  • a reactor is constituted by the multiple coils connected in series and configured as such.
  • window portions 24b are formed on one side surface 24a of a core 24 so that outer peripheral surfaces of respective coils are exposed from the window portions 24b.
  • the outer peripheral surfaces are opposed to a cooler 11.
  • the outer peripheral surfaces directly or indirectly make contact with the cooler 11, heat generated from the coils is dissipated to the cooler 11 so as to cool the reactor. Accordingly, even with the reactor using such multiple coils connected in series, the reactor is cooled by being stacked on the laminated unit 10 of the coolers 11 and the semiconductor modules 12, so that upsizing of the power converter is avoided. Accordingly, a balance between a size of the power converter, a leakage magnetic flux, and cooling performance is increased.
  • the coils 21, 22 (or the coils 31, 32) constituting the reactor 20 (or the reactors 30, 40) are wound so as to form a generally square shape when viewed from the direction of the coil axis CL.
  • the coils of the reactor may be wound so as to form a generally rectangular shape extending in a longitudinal direction (the Y-axis direction in the coordinate system shown in each figure) of the reactor 20 (or the reactors 30, 40), for example.
  • a length of the reactor in the short direction is shortened, so that the size of the reactor is thinner than the reactors 20, 30, 40.
  • a width of the reactor held by the cooler 11 is shortened and a length of the laminated unit 10 in the longitudinal direction (in - the X-axis direction in the coordinate system in each figure) is shortened, thereby making it possible to further improve downsizing of the power converter.
  • the laminated unit 10 corresponds to an example of a laminated unit.
  • the window portion 24b corresponds to an example of a window portion.
  • the one side surface 24a corresponds to an example of "one core side surface opposed to a cooler.” Further, in a case where the core 24 of the reactor has sufficiently high strength, the metal case 25 may not be provided.

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Abstract

A power converter includes a laminated unit and a reactor. The laminated unit is configured such that a plurality of coolers and a plurality of semiconductor modules are laminated. The reactor is stacked on the laminated unit. The reactor includes a plurality of coils, and a core. Coils adjacent to each other are wound in reverse directions to each other and are connected in series. The coils adjacent to each other are arranged side by side in a radial direction of the coils. The core is configured to cover-surroundings of the coils and includes window portion through which outer peripheral surface of the coil is exposed. The outer peripheral surface of the coils makes contact with the cooler through the window portion.

Description

POWER CONVERTER BACKGROUND OF THE INVENTION 1. Field of the Invention
[0001] A technique described in the present specification relates to a power converter in which a reactor is stacked on a laminated unit. The laminated unit is configured such that a plurality of coolers and a plurality of semiconductor modules are laminated. Note that the "reactor" is a passive element using a coil, and is also referred to as an "inductor."
2. Description of Related Art
[0002] An electric vehicle including a hybrid vehicle is equipped with a power converter that converts output power of a battery into alternating current and supplies it to a drive motor. The power converter may include a voltage converter circuit that boosts a voltage of the battery, as well as an inverter circuit that converts direct current into alternating current. These circuits have many switching elements and a reactor. Since heavy-current flows through such a device group (the switching elements and the reactor), a heat generation amount is also large. On that account, the device group is cooled by a cooler. An exemplary unit that cools such a device group collectively is described in Japanese Patent Application Publication No. 2012-5259 (JP 2012-5259 A). The laminated unit is configured such that a plurality of flat semiconductor modules in each of which a switching element is sealed, and a plurality of flat coolers are laminated. Further, the reactor is attached to an end of the laminated unit so as to make contact with the cooler. That is, the plurality of flat coolers cools the semiconductor modules and the reactor. The laminated unit is able to secure a large contact area between the semiconductor modules or the reactor and the coolers, and achieves high coolability while being compact.
[0003] In the meantime, heat generation of the reactor is caused by a coil. On that account, it is preferable that the coil of the reactor be close to the cooler. However, in JP 2012-5259 A, a core, which is a part of the reactor, is provided between the coil and the cooler. If a thickness of the core between the coil and the cooler is thinned, cooling efficiency with respect to the coil, that is, the reactor improves. However, if the thickness of the core is thinned, a leakage magnetic flux of the coil increases. On the other hand, as the core is thicker, the leakage magnetic flux of the coil decreases. That is, when the core is thickened, a loss of the reactor is reduced, but the power converter upsizes by just that much and cooling performance with respect to the reactor is impaired. In the meantime, if the core between the coil and the cooler is thinned, the cooling performance with respect to the reactor improves, and further, Upsizing of the device is avoided. However, the leakage magnetic flux of the coil increases. The present specification provides a balanced power converter that avoids upsizing of a device and considers both measures to the leakage magnetic flux and cooling performance.
SUMMARY OF THE INVENTION
[0004] A power converter described in the present invention includes a laminated unit and a reactor. The laminated unit is configured such that a plurality of coolers and a plurality of semiconductor modules are laminated. The reactor is stacked on the laminated unit. The reactor includes a plurality of coils, and a core. Coils adjacent to each other are wound in reverse directions to each other and are connected in series. The coils adjacent to each other are arranged side by side in a radial direction of the coils. The core is configured to cover surroundings of the coils and includes window portion through which outer peripheral surface of the coil are exposed. The outer peripheral surface of the coil makes contact with the cooler through the window portion.
[0005] According to the technique described in the present specification, a balanced power converter that considers downsizing of a device, measures to a leakage magnetic flux, and cooling performance can be achieved.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] Features, advantages, and technical and industrial significance of exemplary embodiments of the invention will be described below with reference to the accompanying drawings, in which like numerals denote like elements, and wherein:
FIG. 1 is a perspective view of a power converter of a first embodiment;
FIG. 2 is a schematic sectional view taken along a direction of arrows II in FIG. 1;
FIG. 3 is a schematic partial sectional view taken along a direction of arrows III in FIG 2;
FIG- 4 is a perspective view of a reactor in which coils are formed by edgewise - winding;
FIG. 5 is a perspective view of a reactor in which coils are formed by flatwise winding;
FIG. 6 is a perspective view of a power converter of a second embodiment;
FIG. 7 is a partial sectional view around a reactor of the power converter of the second embodiment when taken along an XY plane; and
FIG. 8 is a view illustrating a core in gray in FIG. 4.
DETAILED DESCRIPTION OF EMBODIMENTS
[00Q7] A power converter described, in the present specification includes a laminated unit and a reactor. The laminated unit is configured such that a plurality of flat coolers and a plurality of flat semiconductor modules are laminated alternately. The reactor is stacked adjacent to the cooler of the laminated unit. That is, the reactor is also cooled by the cooler. Note that the plurality of semiconductor modules and the plurality of coolers may be laminated alternately, but some of the semiconductor modules may be laminated successively.
[0008] The reactor includes a plurality of coils and a core covering surroundings of the coils (inside and outside of the coils). Coils adjacent to each other are wound in reverse directions to each other and connected in series, and further arranged side by side in a radial direction thereof. Note that "the coils are wound in reverse directions to each other" indicates that current flowing directions are opposite to each other when the coils are viewed from a coil axis direction. The core includes window portions, and outer peripheral surfaces of the coils are exposed through the window portions. The exposed outer peripheral surfaces of the coils are opposed to the cooler so as to make contact with the cooler. When current is flowed through a pair of coils wound in reverse directions to each other, the current flows through the coils in reverse directions to each other, so that v magnetic fluxes parallel to each other and reverse to each other are caused inside the coils. Those magnetic fluxes are connected to each other outside the coils in their axis direction, so as to form one main loop interlinking with both coils. The main loop is a loop formed from large part of the magnetic fluxes generated from the coils. The window portions are provided in places that avoid the main loop of the magnetic fluxes. That is, outer peripheral surfaces of those parts of the coils which are placed outside the main loop of the magnetic fluxes are exposed through the window portions. By providing the window portions as such, a leakage magnetic flux can be reduced and a loss of the reactor can be restrained. Further, since the exposed outer peripheral surfaces of the coils make contact with the cooler, the reactor (that is, the coils) is cooled efficiently via the outer peripheral surfaces. Further, since the reactor is stacked on the laminated unit and is cooled off hereby, the power converter is not upsized. Accordingly, it is possible to achieve measures to the leakage magnetic. flux and improvement of cooling performance in a good balance while avoiding upsizing of the device, Note that the exposed outer peripheral surfaces of the coils may make contact with the cooler via a heat dissipation sheet.
[0009] Further, in the power converter described in the present invention, it is preferable that the reactor be stacked on an end of the laminated unit in its laminating direction. At this time, among outer peripheral surfaces of the reactor, only that surface of the reactor which is opposed to the cooler is exposed, and the other surfaces may be covered with resin. Accordingly, the window portions of the core are provided only on a core side surface opposed to the cooler, so that a leakage magnetic flux is reduced on core side surfaces that do not make contact with the cooler. As a result, a loss of the reactor can be reduced. Note that an appearance of the reactor in which surroundings of the coils except the window portions are covered with a resin core is often formed in a rectangular solid. [0010] Further, a thickness of that part of the core which is placed outside the coils in a coil axis direction may be thicker than a thickness of that part of the core which is placed outside the coils in a radial direction of the coils. That part of the core which is placed outside the coils in the coil axis direction corresponds to a path of the main loop described above. By thickening that part of the core which corresponds to the path of the main loop, the leakage of the magnetic fluxes is restrained. As a result, the loss of the reactor can be further restrained.
[0011] The coils may be formed by winding a flat wire in an edgewise manner, or the coils may be formed by winding a flat wire in a flatwise manner. In a case of the coils formed by winding a flat wire in an edgewise manner, a narrow side surface of the flat wire in each pitch (one turn of the coil) becomes the outer peripheral surface exposed from the window portion of the core. That is, narrow side surfaces of the flat wire in respective pitches are opposed to the cooler. On that account, an area of the outer peripheral surface of the coil is increased as the number of turns of winding is larger, so that a heat transfer amount from the coil to the cooler increases. Further, the flat wire in each pitch dissipates heat generated from the coil to the cooler. Accordingly, pitches placed on an inner side of the coil and pitches placed on . an outer side of the coil are both cooled generally uniformly. Note that the edgewise winding indicates winding in which a flat wire is wound so that wide surfaces of the flat wire are superimposed on one another toward the coil axis direction. That is, the edgewise winding is winding in which flat surfaces of the flat wire are stacked in the coil axis direction.
[0012] In a case where the coil is formed by winding a flat wire in a flatwise manner, an outermost wide surface of the flat wire corresponds to the outer peripheral surface exposed from the window portion of the core. That is, the outermost flat side surface (wide side surface) of the flat wire is opposed to the cooler, so that the heat of the coil is transmitted to the cooler. In this case, by employing a wider flat wire, the cooling efficiency with respect to the coil, namely, the reactor improves. Note that the flatwise winding indicates winding in which a flat wire is wound so that wide surfaces of the flat wire are superimposed on one another such that the wide surfaces face the radial direction of the coil. That is, the flatwise winding is winding in which the wide surfaces of the flat wire are stacked in the radial direction of the coil.
[0013] The technique described in the present specification can realize a balanced power converter that considers downsizing of a device, measures to a leakage magnetic flux, and cooling performance. Technical details described in the present specification and further improvements thereof are described below.
[0014] A power converter according to a first embodiment is described with reference to the drawings. First described is an outline of a configuration of a power converter 2, with reference to FIG. 1. FIG. 1 is a perspective view of the power converter 2. The power converter 2 is a device provided in a hybrid vehicle or an electric vehicle so as to boost direct-current power of a battery and to convert it into alternating-current power having a frequency suitable for driving of a drive motor (an induction motor, a PM motor, or the like). In view of this, the power converter 2 typically includes a voltage converter circuit and an inverter circuit. These circuits use many power semiconductor elements, and these elements are housed in a plurality of flat semiconductor modules 12 dispersedly. Each of the semiconductor modules 12 is obtained by molding one or more power semiconductor elements with resin. The power semiconductor element is typically an IGBT (Insulated Gate Bipolar Transistor). In FIG. l,*four flat semiconductor modules 12 are illustrated, but a reference sign 12 is assigned to only one of them and the reference sign is omitted in terms of the other semiconductor modules.
[0015] The semiconductor module 12 houses therein a power semiconductor element as such. Further, heavy-current flows through the semiconductor module 12, so its heat generation amount is large. In view of this, in the power converter 2, the laminated unit 10 is configured such that a plurality of flat semiconductor modules 12 is laminated alternately with a plurality of flat coolers 11. The laminated unit 10 is housed in a housing 3. In the present embodiment, a reactor 20 is also stacked on the laminated unit 10 as weir as the semiconductor modules 12. The reactor 20 is stacked on an end of the laminated unit of the semiconductor modules 12 and the coolers 11 so as to make contact with one of the coolers 11. The reactor 20 is an element used for the voltage converter circuit, and heavy-current also flows there through. On that account, similarly to the semiconductor module 12, the reactor 20 has a large heat generation amount, so that cooling by the cooler 11 is necessary. Note that, in the present embodiment, the reactor 20 is configured such that one side surface thereof makes contact with the cooler 11 via an insulating heat dissipation plate 18. The reason for this will be described later.
[0016] In the laminated unit 10, adjacent coolers 11 are connected to each other via connecting pipe 13. -Further, a refrigerant supply pipe 14^nd a refrigerant discharge pipe 15 are connected to an outermost cooler 11 among the plurality of coolers 11. A flow path through which refrigerant flows is formed inside the coolers 11, so refrigerant (e.g., LLC (Long Life Coolant)) supplied from the refrigerant supply pipe 14 spreads to all the coolers 11 through the connecting pipe 13 provided on a side closer to the refrigerant supply pipe 14. Hereby, the refrigerant passing through each of the coolers 11 cools the semiconductor modules 12 and the reactor 20. The refrigerant that absorbs heat from the semiconductor modules 12 and the like then passes through each of the coolers 11, and then discharged out of the refrigerant discharge pipe 15 through the connecting pipe 13 provided on an opposite side.
[0017] In the present embodiment, in order to increase cooling efficiency by the coolers 11, the laminated unit 10 is pressurized in its laminating direction (in an X-axis direction in a coordinate system illustrated in FIG. 1). That is, a leaf spring 5 supported by support pillars 4 of the housing 3 makes pressure contact with one end side of the laminated unit 10 so as to press the other end side (the reactor 20) of the laminated unit 10 against an inner wall of the housing 3, and thus, the laminated unit 10 is held in a sandwiched manner within the housing 3. Since the laminated unit 10 is pressurized in the laminating direction, a degree of adhesion between the semiconductor modules 12 and the coolers 11 and a degree of adhesion between the reactor 20 and the cooler 11 are raised, so heat transfer performance to the coolers 11 improves. As such, in the present embodiment, downsizing of the power converter 2 is achieved by employing the configuration to cool the semiconductor modules 12 and the reactor 20 by the laminated unit 10. [0018] Note that a reference sign 7 indicates a high-capacity smoothing capacitor for use in the inverter circuit and the voltage converter circuit, and the power converter 2 is configured such that the capacitors 7 are also housed in the housing 3. Note that the power converter 2 further includes a control board for controlling the voltage converter 5 circuit and the inverter circuit in addition to these devices, but FIG. 1 does not illustrate the control board and a cover of the housing 3.
- -— - [0019] Referring now to -FIGS. 2 to 4, the following describes the reactor 20.
FIG. 2 is a schematic sectional view of the laminated unit 10. The sectional view schematically illustrates a section of the reactor 20 along a direction of arrows II when the 10 laminated unit 10 is taken along an alternate long and short dash line shown in FIG. 1.
Further, FIG. 3 is a schematic partial sectional view of the laminated unit 10. The sectional view schematically illustrates a section of the reactor 20 and a plane of the laminated unit 10 around the reactor 20 along a direction of arrows III when the reactor 20 is taken along an alternate long and short dash line shown in FIG. 2. Further, FIG. 4 is a 15 perspective view of the reactor 20. In order to assist understanding, a case 25 is cut at a center in an up-down direction and a top half thereof is omitted in FIG. 4.
[0020] The reactor 20 has an appearance formed in a rectangular, solid. The reactor 20 is constituted by two coils 21, 22, a core 24, and the case 25. The coils 21, 22 are winding coils formed by winding a flat wire 23 in an edgewise manner. That is, in the 20 coils 21, 22, the flat wire 23 is wound so that wide side surfaces of the flat wire 23 are stacked so as to face a direction of a coil axis CL (a Z-axis direction in a coordinate system ' illustrated in FIGS. 2 to 4). The coils 21, 22 are wound so as to form a generally square shape when viewed from the direction of the coil axis CL. In the present embodiment, the coils 21, 22 are wound in reverse directions to each other and arranged side by side in a 25 radial direction thereof so as to be connected in series. The coils 21, 22 are housed in the case 25, and their surroundings are covered with the core 24 except some part thereof.
[0021] Note that "the coils are wound in reverse directions to each other" indicates that current flowing directions are opposite to each other when the coils are viewed from a coil axis direction. This will be described below with reference to FIG. 4. As illustrated in FIG. 4, the coil 21 and the coil 22 are made from one flat wire. A reference sign 23s indicates an initial point of the winding, and a reference sign 23e indicates an end point of the winding. The coil 21 and the coil 22 are both wound clockwise toward a positive direction of the Z-axis. However, when viewed from the initial point 23s toward the end point 23e of the winding, the coil 21 is wound clockwise, and the coil 22 is wound counterclockwise, and thus, they are wound in reverse directions to each other. The direction from the initial point 23s toward the end point 23e of the winding indicates a direction where current flows. Thus, "the coils are wound in reverse directions to each other" indicates that winding directions are reverse to each other in the direction where current flows. In other words, the coils 21 and 22 are wound so that respective magnetic fluxes caused in respective coils at the time when current is applied thereto are directed toward reverse directions.
[0022] The core 24 is obtained by hardening resin mixed with soft magnetic material particles. Powdery resin (resin powder including soft magnetic material particles) before hardening is filled into the case 25, so as to form the core 24 covering generally entire surroundings of the coils 21, 22 (inside and outside of the coils). In other words, the core 24 molds the coils 21, 22 with resin, . In the figure, the core 24 corresponds to a whole internal space of the case 25. However, in order to easily see the coils inside the core 24 and broken lines (broken lines indicating magnetic fluxes) for description, only a contour of the core 24 is illustrated by an alterriate long and two short dashes line. See FIG. 8 in which the core 24 in FIG. 4 is illustrated in gray. FIG. 8 is the same as FIG. 4 except that the core 24 is illustrated in gray. The core 24 of the present embodiment is formed in a rectangular solid as a whole, and window portions 24b through which outer peripheral surfaces 21a, 22a of the coils 21, 22 are exposed outside are formed on one side surface 24a thereof. See FIG. 8 in particular about the window portions 24b. In FIG. 8, it is shown well that the outer peripheral surfaces 21a, 22a of the coils 21, 22 are exposed from the window portions 24b provided in the core 24 in gray. That is, when the core 24 is viewed from a direction of the coil axis CL, the coils 21, 22 are placed on the one side surface 24a of the core 24 in a biased manner. Accordingly, on the one side surface 24a, the outer peripheral surfaces 21a, 22a of the coils 21, 22 are not covered with the core 24, but exposed outside the core 24 (see FIGS. 3, 4). Note that the core 24 is filled in the internal space of the case 25, but FIG. 4 shows the coils 21, 22 without the core 24, in order to easily understand the figure. Further, an arrow indicated by a reference sign 24a indicates a side surface parallel to a YZ plane and placed in a positive direction of the X-axis in the figure, among side surfaces of the core 24 of the rectangular solid. Furthermore^ outside of rectangular shapes indicative of the window portions 24b is filled with the core 24, and the coils 21, 22 are not visible from outside except parts inside the rectangular shapes indicative of the window portions 24b. A shape of the core 24 in its short direction is formed unsymmetrically when the core 24 is viewed in terms of the coils 21, 22. The one side surface 24a of the core 24 including the window portions 24b may be formed in a step of forming the core 24 by molding, or may be formed by cutting and grinding after the core 24 is formed by molding. Hereinafter, those parts of the core 24 which is removed to form the window portions 24b are conveniently referred to as "cut portions." ;- . .. . .. . . . .
[0023] Further, the core 24 is set to have a relatively thin (small) wall thickness (ranges T2 and T3 in FIG 3) in those parts of the core 24 which are placed radially outside . the coils 21, 22, except the cut portions. Hereby, since a thermal resistance is small as ' compared with a case where the wall thickness of the core 24 is thick, heat of the core 24 is easily transmitted to the case 25. On the other hand, the core 24 is set to have a thick wall thickness (ranges Tl shown in FIG. 2) in those parts of the core 24 which are placed outside the coils in the direction of the coil axis CL. By thickening a thickness Tl of the core 24 outside the coils in the direction of the coil axis CL, a leakage magnetic flux in this direction is reduced. When the thicknesses of the core outside the coils are compared with each other, relationships of Tl > T2, Tl > T3 are established.
[0024] The case 25 is made of a metal plate in a box shape of a rectangular solid, and is made of a metallic material, such as aluminum, having high heat conductivity. In the present embodiment, the case 25 has an opening 25a that is opened generally over one side surface. The one side surface 24a of the core 24 is exposed from the opening 25a, and further, the outer peripheral surfaces 21a, 22a of the coils 21, 22 are exposed outside therefrom. The outer peripheral surfaces 21a, 22a are configured such that narrow side surfaces 23a of respective pitches (respective turns) of the flat wire 23 wound in an edgewise manner are stacked in the direction of the coil axis CL. Note that it is necessary to hold the coils 21, .22 at a predetermined position in the case 25. In view of this, a support portion for holding the coils 21, 22 may be formed within the case 25. This makes it -easy to position the coils 21, 22 -in the case 25. Note that, on a bottom face of the case 25, through holes or notch portions through which the flat wire 23 led out of respective ends of the coils 21, 22 passes are formed, although not illustrated in FIG. 4.
[0025] In the present embodiment, the reactor 20 is configured as such. Hereby, a part of the outer peripheral surface (the one side surface 24a) of the core 24 is exposed from the opening 25a of the case 25, and parts of the outer peripheral surfaces 21a, 22a of the coils 21, 22 are further exposed from the window portions 24b formed on the one side surface 24a. On that account, by stacking the reactor 20 on the cooler 11 as described above, the exposed outer peripheral surfaces 21a, 22a of the coils 21, 22 are opposed to the cooler 11, so the outer peripheral surfaces 21a, 22a of the coils 21, 22 make contact with the cooler 11. Note that "the outer peripheral surfaces 21a, 22a make contact with the cooler 11" includes a case where a heat dissipation seat or the like is sandwiched therebetween. The reason is because the heat dissipation seat can be considered as part of the cooler 11.
[0026] Note that, in the present embodiment, the coils 21, 22 wound in an edgewise manner are employed for the reactor 20. Accordingly, areas of the outer peripheral surfaces 21a, 22a increase as the number of turns of winding is larger. On that account, heat dissipation effect with respect to the cooler 11 increases along with an increase of the number of turns of winding. Further, respective pitches (respective turns) of the stacked flat wire 23 dissipate heat of the coils 21, 22 to the cooler 11, so that the coils 21, 22 dissipate heat generally uniformly regardless of inside or outside of the coils 21, 22.
' [0027] Further, since respective winding directions of the coils 21, 22 are reverse to each other, when current is flowed through the coils 21, 22, the current flows through the coil 21, 22 in reverse directions to each other. In view of this, magnetic fluxes MF reverse to each other are caused inside the coils 21 , 22 (see FIG. 3), so as to form one main loop of the magnetic fluxes MF (see FIG. 2). The magnetic fluxes generated from the coils 21, 22 through which the current flows in reverse directions to each other form the main loop that strengthens the magnetic fluxes in the same direction in coils adjacent to each other in-FIG. 2 (in a core central part where the coils 21 and 22 are opposed to each - other). Meanwhile, in FIG. 2, magnetic fluxes generated from those parts of the coils 21, 22 which are placed on a core outer side are weaker than the magnetic fluxes of the main loop.
[0028] Hereby, the coils 21, 22 do not function as a sum of individual small reactors, but the coil 21 and the coil 22 function as one large reactor. The core 24 through which the main loop of the magnetic fluxes MF passes has a large wall thickness (the ranges Tl in FIG. 2) in those parts outside the coils along the coil axis CL, so a leakage magnetic flux of the main loop is Teduced. Further, those cut portions of the core 24 which include the window portions 24b formed on the one side surface 24a of the core 24 are provided at positions that avoid the main loop of the magnetic fluxes MF. Accordingly, even in the configuration in which the core 24 is not provided on the one side surface 24a, the main loop of the magnetic fluxes MF is hard to be affected. That is, the magnetic fluxes MF of the main loop do not leak from the one side surface 24a (the, cut portions) of the core 24, or have little leakage magnetic flux.
[0029] In the present embodiment, in order to secure an electric insulating property to the metal cooler 11, the heat dissipation plate 18 is provided between the cooler 11 and the reactor 20 (see FIG. 3). The heat dissipation plate 18 is a thin insulating plate made of an insulating material having a high thermal conductive characteristic. Hereby, the outer peripheral surfaces 21a, 22a of the coils 21, 22 make contact with the heat dissipation plate 18 through the window portions 24b, so heat of the coils 21, 22 is transmitted to the cooler 11. Thus, the coils 21, 22 are cooled by the cooler 11. Note that, in a case where an electric insulation treatment is performed on a surface of the cooler 11, the heat dissipation plate 18 can be omitted. In this case, the outer peripheral surfaces 21a, 22a of the coils 21, 22 directly make contact with the cooler 11, so heat generated from the coils 21, 22 is directly transmitted to the cooler 11 and cooling efficiency by the cooler 11 can be raised.
[0030] As described above, the power converter 2 of the present embodiment includes: the laminated unit 10 configured such that the plurality of flat coolers 11 and the plurality of flat semiconductor modules 12 are laminated alternately; and the reactor 20 stacked on an end of the laminated unit 10 in the laminating direction so as to be cooled by the cooler 11. The reactor 20 includes: the plurality of coils 21, 22 configured such that the coils 21, 22 adjacent to each other are wound in reverse directions to each other and are connected in series to each other, the coils 21, 22 being arranged side by side in the radial direction; and the core 24 covering surroundings of the coils 21, 22 (inside and outside of the coils). The core 24 includes the window portions 24b through which the outer peripheral surfaces 21a, 22a of the coils 21, 22 are exposed, and the exposed outer " peripheral surfaces 21a, 22a of the coils 21, 22 are opposed to the cooler 11. The outer - peripheral surfaces 21a, 22a of the coils 21, 22 make contact with the cooler 11. Accordingly,, when current is flowed through two coils 21, 22 thus connected, the current flows through the coils 21, 22 in reverse directions to each other. Hereby, magnetic fluxes MF reverse to each other are caused in the coils 21, 22, so as to form one main loop interlinking with the coils 21, 22.
[0031] Accordingly, even if those parts of the outer peripheral surfaces 21a, 22a of the coils 21, 22 which are placed outside the main loop of the magnetic fluxes MF are exposed from the window portions 24b, the window portions 24b are provided in places that avoid the main loop of the magnetic fluxes MF, so an interlinkage flux due to a leakage magnetic flux is reduced and a loss of the reactor 20 is restrained. Further, since the exposed outer peripheral surfaces 21a, 22a of the coils 21, 22 are opposed to the cooler 11, the outer peripheral surfaces 21a, 22a make contact with the cooler 11 so as to cool the reactor 20 by dissipating heat generated from the coils 21, 22 to the cooler 11. Thus, the reactor 20 is stacked on the laminated unit 10 including the coolers 11 and the semiconductor modules 12 and is cooled hereby, so that the power converter 2 is downsized. Accordingly, a balance between a size (avoidance of upsizing) of the power converter 2, a leakage magnetic flux, and cooling performance is increased.
[0032] Further, in the power converter 2 of the present embodiment, that part of the core 24 constituting the reactor 20 which is placed outside the coils 21, 22 in the radial direction has a thin wall thickness (except the side where coil side surfaces are exposed). Hereby, a thermal resistance is reduced as compared with a case where the wall thickness -
Γ
of the core 24 is large. Accordingly, heat of the core 24 is easily transmitted to the case 25 and cooling performance is thus improved. On the other hand, those parts of the core 24 which are placed outside the coils in the direction of the coil axis CL have a large wall thickness. This reduces a leakage magnetic flux in the direction of the coil axis CL.
[0033] In the above embodiment, winding coils formed by winding the flat wire 23 in an edgewise manner are employed as. the coils 21, 22. As a modified example of the present embodiment, winding coils formed by winding a flat wire in a flatwise manner may be employed. That is, in this modified example, a reactor 30 is configured such that surroundings of coils 31, 32 formed by winding a flat wire 33 in a flatwise manner are covered with a core 24 and housed in a case 25, as illustrated in FIG. 5. The flat .wire 33 is wound so that its wide side surfaces are stacked so as to face a radial direction of the coils 31, 32 (a Y-axis direction in a coordinate system shown in FIG. 5). FIG. 5 is a perspective view of the reactor 30. In FIG. 5, a top half of the case 25 is cut similarly to FIG. 4, and further, the core 24 is illustrated by a contour indicated by an alternate long and two short dashes line. Note that the same reference sign is assigned to substantially the same component as in the reactor 20, and a description thereof is omitted. Further, similarly to FIG. 4, the coils 31, 32 are illustrated without the core 24, in order to easily understand the figure. Furthermore, outside of rectangular shapes indicative of window portions 24b is filled with resin of the core 24, so that the coils 31, 32 are not visible from outside except parts inside the rectangular shapes indicative of the window portions 24b.
[0034] Similarly to the reactor 20, the reactor 30 of the modified example is configured such that the coils 31, 32 are wound in reverse directions to each other and are connected in series. The meaning of "winding in reverse directions" is the same as described above. The coils 31, 32 are housed in the case 25, and their surroundings are covered with the core 24 except some part thereof. Even in the reactor 30, outer peripheral surfaces 31a, 32a of the coils 31, 32 are exposed outside from the window portions 24b formed on one side surface 24a of the core 24. On that account, by stacking the reactor 30 on the cooler 11 as described above, the exposed outer peripheral surfaces 31a, 32a of the cails 31, 32 are opposed to the cooler 11, so the outer peripheral surfaces
31a, 32a of the coils 31, 32 make contact with the cooler 11. Note that, since the coil 31, 32 are wound in a flatwise manner, outer peripheral surfaces 33a, which are outermost wide side surfaces of the flat wire 33 thus wound, are exposed from the window portions 24b as the outer peripheral surfaces 31a, 32a. Particularly, in a case where a width of the wide side surfaces of the flat wire 33 is large, an area of the flat wire 33 making contact with the cooler 11 is large. Accordingly, it is possible to efficiently dissipate heat of the coils 31, 32 by dissipating the heat from the outer peripheral surfaces 31a, 32a to the cooler 11.
[0035] The power converter 2 of the above embodiment or its modified example employs a configuration in which the window portions 24b of the core 24 through which the outer peripheral surfaces 21a, 22a (or the outer peripheral surfaces 31a, 32a) of the coils 21, 22 (or the coils 31, 32) are exposed are provided on the one side surface 24a of the core 24, and no window portion 24b is provided on its opposite side. That is, the cut portions are formed only on the one side surface 24a of the core 24, so that the shape of the core 24 in the short direction (the X-axis direction) is formed unsymmetrically. Note that the coils 21, 22 are covered with the core 24 on the other side surfaces except the one side surface 24a of the core 24. Thus, the window portions 24b are provided only on the one side surface 24a opposed to the cooler 11. Since the core 24 is provided on the opposite side, a magnetic flux to leak is reduced.
[0036] Next will be described a power converter 2a of a second embodiment with the use of FIGS. 6, 7. FIG. 6 is a perspective view of the power converter 2a. FIG. 7 is a partial sectional view of the power converter 2a, taken along an XY plane. FIG. 7 is a partial sectional view- around a reactor 40 in the power converter 2a. Since the reactor 40 has the same configuration as the reactor 20 in the first embodiment, the same reference signs as used in the reactor 20 of the first embodiment are used to indicate respective portions in the reactor.
[0037] In the power converter 2 of the first embodiment, the reactor 20 is stacked on the end of the laminated unit 10. That is, only one side surface of the reactor 20 makes contact- with -the cooler 11-. In- -contrast, in the power converter 2a of the second embodiment, the reactor 40 is stacked so that coolers 11 are placed on both sides of the reactor 40. Since the coolers 11 make contact with both sides of the reactor 40, cooling effect on the reactor 40 further increases.
[0038] The power converters 2, 2a of the first, second embodiments employ a configuration in which the window portions 24b of the core 24 through which the outer peripheral surfaces 21a, 22a of the coils 21, 22 are exposed are provided on the one side surface 24a of the core 24, and no window portion 24b is provided on its opposite side. " That is, the cut portions are formed only on the one side surface 24a of the core 24, so that- the shape of the core 24 in the short direction (the X-axis direction) is formed unsymmetrically. Thus, the window portions 24b are provided only on the one side surface 24a opposed to the cooler 11. Since the core 24 is provided on the opposite side, a magnetic flux to leak is reduced. Accordingly, a leakage magnetic flux is reduced as compared with a case where the window portions 24b are formed on both sides of the core 24 in the short direction, so that a loss of the reactor 40 is further restrained. On that account, a loss of the reactor 20 (or the reactor 40) can be further reduced.
[0039] In the meantime, it is also preferable to employ the . following configuration when the coolers 11 are provided on both sides of the reactor 40 as described in the second embodiment. That is, cut portions are formed on both sides of the core 24 in the short direction (the X-axis direction) so that the shape of the core 24 in the short direction is formed symmetrically. In a case where the configuration is employed, side surfaces 23a of the flat wire 23 are exposed from the window portions 24b in terms of those outer peripheral surfaces 21a, 22a of the coils 21, 22 which are placed on both sides of the core 24 in the short direction. Since the outer peripheral surfaces 21a, 22a of the coils 21, 22 are opposed to those coolers 11 on both sides which sandwich the reactor 40, the coils 21, 22 can be cooled by the coolers 11 from both sides. Hereby, cooling performance is increased more. Note that, in this configuration, when it is necessary to secure electric insulation to the coolers 11, the reactor 40 makes contact with the coolers 11 via heat dissipation plates 18 provided on both sides of the reactor 40. Such a configuration in which the coils are exposed on two parallel-flat surfaces of the reactor and respective side surfaces of the coils make contact with the coolers can be also realized by the reactor of FIG. 5 in which the coils are wound in a flatwise manner.
[0040] In the power converter 2 of the above embodiment or its modified example, the reactor 20 (or the reactors 30, 40) is constituted by two coils 21, 22 connected in series (or two coils 31, 32 connected in series), but the reactor may be constituted by multiple coils connected in series. For example, three or more coils wound in an edgewise manner or flatwise manner are arranged in a radial direction and are positioned so that winding directions of coils adjacent to each other among them are reverse to each other, and then, all the coils are connected in series to each other. A reactor is constituted by the multiple coils connected in series and configured as such. Even in such a reactor, window portions 24b are formed on one side surface 24a of a core 24 so that outer peripheral surfaces of respective coils are exposed from the window portions 24b. Hereby, the outer peripheral surfaces are opposed to a cooler 11. When the outer peripheral surfaces directly or indirectly make contact with the cooler 11, heat generated from the coils is dissipated to the cooler 11 so as to cool the reactor. Accordingly, even with the reactor using such multiple coils connected in series, the reactor is cooled by being stacked on the laminated unit 10 of the coolers 11 and the semiconductor modules 12, so that upsizing of the power converter is avoided. Accordingly, a balance between a size of the power converter, a leakage magnetic flux, and cooling performance is increased.
[0041] Further, in the power converter 2 of the above embodiment or its modified example, the coils 21, 22 (or the coils 31, 32) constituting the reactor 20 (or the reactors 30, 40) are wound so as to form a generally square shape when viewed from the direction of the coil axis CL. Alternatively, the coils of the reactor may be wound so as to form a generally rectangular shape extending in a longitudinal direction (the Y-axis direction in the coordinate system shown in each figure) of the reactor 20 (or the reactors 30, 40), for example. Hereby, a length of the reactor in the short direction (in the X-axis direction in the coordinate system shown in each figure) is shortened, so that the size of the reactor is thinner than the reactors 20, 30, 40. Accordingly, a width of the reactor held by the cooler 11 is shortened and a length of the laminated unit 10 in the longitudinal direction (in - the X-axis direction in the coordinate system in each figure) is shortened, thereby making it possible to further improve downsizing of the power converter.
[0042] Below are notes regarding the technique explained in the embodiments.
The laminated unit 10 corresponds to an example of a laminated unit. Further, the window portion 24b corresponds to an example of a window portion. Further, the one side surface 24a corresponds to an example of "one core side surface opposed to a cooler." Further, in a case where the core 24 of the reactor has sufficiently high strength, the metal case 25 may not be provided.
[0043] The specific example of the invention has been explained in detail. However, the example is for illustration only, and does not limit the scope of the claims. The technique described in the scope of the claims includes the foregoing example with various modifications and changes. Technical elements described in the present specification or the drawings exhibit a technical usability solely or in various combinations, and are not limited to combinations as described in the claims as of filing the present application. Further, the technique exemplified in the present specification or the drawings can achieve a plurality of objects at the same time, and has a technical usability by achieving one of those objects.

Claims

CLAIMS:
1. A power converter comprising:
a laminated unit configured such that a plurality of coolers and a plurality of semiconductor modules are laminated; and
a reactor stacked on the laminated unit, the reactor including:
a plurality of coils configured such that coils adjacent to each other are -wound in reverse directions to each other and are connected in series, the coils adjacent to each other being arranged side by side in a radial direction of the coils; and
a core configured to cover surroundings of the coils, the core including a window portion through which outer peripheral surface of the coil is exposed, and the outer peripheral surface of the coil making contact with the cooler through the window portion.
2. The power converter according to claim 1, wherein:
the reactor is stacked on an end of the laminated unit in a laminating direction of the laminated unit; and . . . . ,
the reactor is configured such that surfaces except a surface opposed to the cooler is covered with the core.
3. The power converter according to claim 1 or 2, wherein:
a second thickness of the core is thicker than a first thickness of the core;
the first thickness is a thickness of a part of the core which is placed outside the coils in the radial direction of the coils; and
the second thickness is a thickness of the part of the core which is placed outside the coils in an axis direction of the coils.
4. The power converter according to any one of claims 1 to 3, wherein:
each coli is a wound flat wire that is wound in an edgewise manner; and a narrow side surface of the flat wire in each pitch is exposed through the window portion.
5. The power converter according to any one of claims 1 to 3, wherein:
each coil is a wound flat wire that is wound in a flatwise manner; and
an outermost wide side surface of the flat wire is exposed through the window portion.-
PCT/IB2014/002693 2013-12-11 2014-12-09 Power converter WO2015087129A1 (en)

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