JP2014072344A - Smoothing capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a smoothing capacitor which has a favorable structure from a point of view of suppressing surge voltage accompanying switching operation.SOLUTION: An outer surface of a main body part 50a of a smoothing capacitor 50 includes an element arrangement surface S1 integrally formed with a dielectric part 53. The element arrangement surface S1 has a positive electrode side connection electrode P1 electrically connected to a positive electrode terminal 51 and a negative electrode side connection electrode P2 electrically connected to a negative electrode terminal 52 and is configured in a way that switching elements 10 can be arranged in a state that they can be connected to at least either the positive electrode side connection electrode P1 or the negative electrode side connection electrode P2. Inside the body part 50a, an internal conductive layer 70 extending along the element arrangement surface S1 is provided. The internal conductive layer 70 is formed so that a current flow direction viewed in a direction (Z direction) orthogonal to the element arrangement surface S1 has a component of a direction which is directed from the negative electrode terminal 52 to the positive electrode terminal 51 in a reference direction (X direction).

Description

  The present invention relates to a smoothing capacitor that includes a main body portion having a dielectric portion interposed between electrodes, and suppresses fluctuations in DC voltage supplied to a switching element.

  In a semiconductor integrated circuit, it is necessary to prevent malfunctions due to switching noise. For preventing such malfunction, there is a technique described in, for example, JP-A-8-181445 (Patent Document 1). In the description of the background art section, reference numerals in Patent Document 1 are quoted in []. In FIG. 1 of Patent Document 1, an LSI chip [11] is arranged on a printed wiring board [14] via a ceramic multilayer substrate [20], and a capacitor section [20] is placed inside the ceramic multilayer substrate [20]. 23] is described. As a result, as described in paragraphs 0016 to 0017 of the document, it is possible to filter the switching noise by the capacitor unit [23] and prevent the LSI chip [11] from malfunctioning.

  Incidentally, a switching element unit including a switching element may be provided with a smoothing capacitor that suppresses fluctuations in the DC voltage supplied to the switching element. However, the capacitor section [23] described in Patent Document 1 is provided for the purpose of preventing malfunction from occurring in the LSI chip [11]. Patent Document 1 does not describe a smoothing capacitor, and does not describe any technique for suppressing a surge voltage associated with a switching operation when the smoothing capacitor is provided in a switching element unit.

JP-A-8-181445 (paragraphs 0016 to 0017, FIG. 1, etc.)

  Therefore, it is desired to realize a smoothing capacitor having a preferable configuration from the viewpoint of suppressing a surge voltage accompanying a switching operation.

  According to the present invention, there is provided a main body configured to have a dielectric portion interposed between electrodes, and a characteristic configuration of a smoothing capacitor that suppresses fluctuations in DC voltage supplied to a switching element is On the outer surface, an element arrangement surface formed integrally with the dielectric portion and intersects the element arrangement surface at an end of the element arrangement surface on one side in a reference direction set along the element arrangement surface And a second plane that intersects the element arrangement surface at the end of the element arrangement surface on the other side in the reference direction, and a positive electrode terminal is formed on the first plane, A negative electrode terminal is formed on the second plane, and the element arrangement surface includes a positive electrode side connection electrode electrically connected to the positive electrode terminal, and a negative electrode side connection electrode electrically connected to the negative electrode terminal. And having said An internal conductive layer configured to be capable of disposing the switching element in a state of being electrically connected to at least one of the pole-side connection electrode and the negative-electrode-side connection electrode, and extending along the element disposition surface inside the main body portion And the internal conductive layer is formed so that a current flow direction in a direction perpendicular to the element arrangement surface has a component in a direction from the negative electrode terminal toward the positive electrode terminal in the reference direction. There is in point.

  In the present application, regarding the shape of a member, “extends along a certain surface” means that the surface extends as a reference surface, and the extending direction of the member is not limited to a shape parallel to the reference surface, but the whole or a part of the member. The extending direction may be a direction intersecting the reference plane, and includes a shape in which the extending direction of the entire member is within a predetermined range (for example, 5 degrees or less) with respect to the reference plane. It is used as a concept.

  According to the above characteristic configuration, the effective inductance of the positive electrode side connection electrode and the negative electrode side connection electrode constituting the electrical connection path between the switching element and the terminal of the smoothing capacitor is reduced by the current flowing through the internal conductive layer. be able to. That is, when the smoothing capacitor performs the function of suppressing fluctuations in the DC voltage supplied to the switching element arranged on the element arrangement surface, current flows from the positive electrode terminal to the switching element via the positive electrode side connection electrode, Alternatively, a current flows from the switching element to the negative electrode terminal via the negative electrode side connection electrode. Here, the positive electrode terminal and the negative electrode terminal are formed at the end of the element arrangement surface in the reference direction, and the positive electrode side connection electrode and the negative electrode side connection electrode are provided in the element arrangement surface. The direction has a component in the direction from the positive electrode terminal to the negative electrode terminal in the reference direction for both the positive electrode side connection electrode and the negative electrode side connection electrode. On the other hand, the internal conductive layer is formed so that the current flow direction in the direction perpendicular to the element arrangement surface has a component in the direction from the negative terminal to the positive terminal in the reference direction. Therefore, the magnetic field generated by the current flowing through the positive electrode side connection electrode or the magnetic field generated by the current flowing through the negative electrode side connection electrode is weakened or canceled by the magnetic field generated by the current flowing through the internal conductive layer, and the positive electrode side connection electrode or The effective inductance of the negative electrode side connection electrode can be reduced. As a result, the surge voltage (temporary voltage rise) accompanying the switching operation of the switching element can be suppressed.

  Furthermore, according to the above-described characteristic configuration, the switching element can be arranged in a state where the element arrangement surface included in the outer surface of the main body is electrically connected to at least one of the positive electrode side connection electrode and the negative electrode side connection electrode. Therefore, the length of the electrical connection path between the switching element and the terminal of the smoothing capacitor is shorter than when the switching element is arranged separately from the smoothing capacitor because it does not have such an element arrangement surface. Therefore, the inductance of the electrical connection path can be reduced. Also from this point, the surge voltage can be suppressed.

  As mentioned above, according to said characteristic structure, the smoothing capacitor which has a suitable structure from a viewpoint of suppression of a surge voltage is realizable. And according to said characteristic structure, since the internal conductive layer for suppressing a surge voltage is provided in the inside of the main-body part of a smoothing capacitor, when comprising a switching element unit using such a smoothing capacitor The number of parts can be reduced. In addition, by suppressing the surge voltage, it is possible to reduce the power loss that causes the switching element to generate heat, simplify the cooling mechanism required for heat dissipation, and to improve the resistance required for the switching element and peripheral components. Voltage performance can be kept low. That is, it is possible to reduce the size and manufacturing cost of the switching element unit including the smoothing capacitor.

  Here, the internal conductive layer has a portion that overlaps at least one of the positive electrode side connection electrode and the negative electrode side connection electrode when viewed in a direction orthogonal to the element arrangement surface, and the switching on the element arrangement surface. It is preferable that the structure is formed so as to have a portion overlapping with the element arrangement region.

  In the present application, regarding the arrangement of two members, “having overlapping portions when seen in a certain direction” means that when a virtual straight line parallel to the line-of-sight direction is moved in each direction orthogonal to the virtual straight line, It means that a region where the virtual straight line intersects both of the two members exists at least in part.

  According to this configuration, the connection electrode and the internal conductive layer are connected to the connection electrode (one or both of the positive electrode side connection electrode and the negative electrode side connection electrode) having a portion overlapping with the internal conductive layer when viewed in the direction orthogonal to the element arrangement surface. It is easy to increase the effect of reducing the effective inductance of the connection electrode by shortening the distance between the connection electrodes. Further, since the internal conductive layer is formed so as to have a portion that overlaps with the switching element placement region when viewed in the direction orthogonal to the element placement surface, the overlap in the direction parallel to the element placement surface corresponds to the overlap. The size of the smoothing capacitor can be reduced.

  Further, a positive side internal electrode extending from the positive terminal to the negative terminal side in the reference direction and a negative side internal electrode extending from the negative terminal to the positive terminal side in the reference direction are formed in the main body. The positive electrode side internal electrode and the negative electrode side internal electrode are both formed on the side opposite to the element arrangement surface with respect to the internal conductive layer in a direction perpendicular to the element arrangement surface. It is preferable.

  According to this configuration, a conductive member capable of affecting a magnetic field generated by a current flowing through the internal conductive layer is not disposed between the internal conductive layer and the element layout surface in a direction orthogonal to the device layout surface. Therefore, it is easy to effectively reduce the effective inductance of the positive electrode side connection electrode and the negative electrode side connection electrode. Also, with this configuration, the distance between the positive electrode side connection electrode and the internal conductive layer and the distance between the negative electrode side connection electrode and the internal conductive layer are shortened so that the positive electrode side connection electrode and the negative electrode side connection electrode are effective. It becomes easy to increase the effect of reducing the inductance.

  As described above, the positive electrode side internal electrode and the negative electrode side internal electrode are both formed on the side opposite to the element arrangement surface with respect to the internal conductive layer in a direction orthogonal to the element arrangement surface. The end regions on the negative electrode terminal side in the reference direction of the internal conductive layer and the positive electrode side internal electrode are connected to each other, and the positive electrode terminal side end in the reference direction of the internal conductive layer Preferably, the partial region is connected to the positive electrode side connection electrode, and the positive electrode side connection electrode is connected to the positive electrode terminal via the internal conductive layer.

  Alternatively, in the configuration in which both of the positive electrode side internal electrode and the negative electrode side internal electrode are formed on the side opposite to the element arrangement surface with respect to the internal conductive layer in a direction orthogonal to the element arrangement surface, The end regions on the positive electrode terminal side in the reference direction of the internal conductive layer and the negative electrode side internal electrode are connected to each other, and the end region on the negative electrode terminal side in the reference direction of the internal conductive layer is A configuration in which the negative electrode side connection electrode is connected to the negative electrode terminal via the internal conductive layer is also preferable.

  According to these configurations, the internal conductive layer can be formed by effectively using the internal electrode formed inside the main body.

  In the smoothing capacitors having the above-described configurations, it is preferable that the dielectric portion is formed of a ceramic material.

  According to this configuration, it is easy to improve the surge voltage resistance performance of the smoothing capacitor.

It is a perspective view of the switching element unit which concerns on embodiment of this invention. It is the perspective view seen from the direction different from FIG. 1 of the switching element unit which concerns on embodiment of this invention. It is a top view of a switching element unit concerning an embodiment of the present invention. It is IV-IV sectional drawing in FIG. It is VV sectional drawing in FIG. It is a top view of the 1st smoothing capacitor concerning the embodiment of the present invention. It is a schematic diagram which shows the structure of the inverter circuit which concerns on embodiment of this invention. It is sectional drawing of the switching element unit which concerns on other embodiment of this invention. It is a top view of the 1st smoothing capacitor concerning other embodiments of the present invention. It is a top view of the switching element unit which concerns on other embodiment of this invention.

  Embodiments of the present invention will be described with reference to the drawings. Here, a case where the smoothing capacitor according to the present invention is applied to an inverter circuit 91 (see FIG. 7) for controlling the rotating electrical machine 2 will be described as an example. Specifically, in the present embodiment, the smoothing capacitor (first smoothing capacitor 50) is provided in the switching element unit 1 and is arranged in the first smoothing capacitor 50 as shown in FIGS. The switching element 10 constituting the inverter circuit 91 is disposed on the surface S1. That is, in the present embodiment, the switching element 10 arranged on the element arrangement surface S1 of the first smoothing capacitor 50 is an electronic element that constitutes the inverter circuit 91, and the switching element 10 includes a DC power and an AC power. Power conversion between.

  In the following description, unless otherwise specified, “upper” refers to the + Z direction in FIG. 1, and “lower” refers to the −Z direction in FIG. As shown in FIG. 4, the Z direction is a direction orthogonal to the element arrangement surface S1, and the direction from the element arrangement surface S1 toward the switching element 10 arranged on the element arrangement surface S1 is positive. In other words, the + Z direction coincides with the direction of the normal vector that goes outward from the element arrangement surface S1. The X direction is a reference direction set along the element arrangement surface S1, and the direction from the positive electrode terminal 51 to the negative electrode terminal 52 side of the first smoothing capacitor 50 is positive as shown in FIG. The Y direction is a reference orthogonal direction orthogonal to the reference direction (X direction) along the element arrangement surface S1. The direction (positive or negative) in the Y direction is defined such that the X direction, the Y direction, and the Z direction form a right-handed orthogonal coordinate system in order, as shown in FIG. In the present specification, terms relating to the arrangement direction, arrangement position, and the like of each member are used as a concept including a state in which there is a difference due to an error (an error that is acceptable in manufacturing).

1. Schematic Configuration of Switching Element Unit As shown in FIGS. 1 to 3, the switching element unit 1 according to this embodiment includes a switching element 10, a diode element 20, and a first smoothing capacitor 50. As shown in FIG. 7, the switching element 10 and the diode element 20 provided in the switching element unit 1 are electrically connected to each other in series to form a series element unit 30. The switching element unit 1 includes at least one set of the switching element 10 and the diode element 20 (hereinafter referred to as “electronic element set”) forming the series element unit 30. In the present embodiment, as shown in FIG. 3, the switching element unit 1 includes a plurality of electronic element sets, specifically, an electronic element set that forms the first series element unit 30a, and a second series element unit. Two electronic element sets are provided, with the electronic element set forming 30b.

  The first smoothing capacitor 50 is a circuit component that suppresses fluctuations in the DC voltage supplied to the series element unit 30 (that is, smoothes the DC voltage). In the present embodiment, as shown in FIG. 7, the rotating electrical machine drive circuit that drives the rotating electrical machine 2 includes a booster circuit 92 in addition to the inverter circuit 91, and includes a first smoothing capacitor 50 as a smoothing capacitor. Two smoothing capacitors 60 are provided in the rotating electrical machine drive circuit. The booster circuit 92 is a circuit for boosting the DC voltage of the DC power supply 3, and includes two switching elements 10 and a total of two diode elements 20 electrically connected in parallel to the two switching elements 10, And the reactor 82 is comprised. In the reactor 82, energy is intermittently accumulated according to the switching of the switching element 10. The DC power source 3 is constituted by, for example, a battery, a capacitor, and the like. In the present embodiment, the first smoothing capacitor 50 corresponds to the “smoothing capacitor” in the present invention.

  The first smoothing capacitor 50 is electrically connected in parallel to the DC side of the inverter circuit 91 and suppresses fluctuations in the DC voltage supplied to the series element unit 30 constituting the inverter circuit 91. That is, the first smoothing capacitor 50 suppresses fluctuations in the DC voltage supplied to the switching element 10 constituting the series element unit 30. The first smoothing capacitor 50 is electrically connected in parallel with a discharge resistor 81 for discharging the charge stored in the first smoothing capacitor 50 when the power is turned off. The second smoothing capacitor 60 is electrically connected to the DC power supply 3 in parallel and suppresses fluctuations in the DC voltage supplied to the switching element 10 constituting the booster circuit 92. That is, the first smoothing capacitor 50 is a post-boosting smoothing capacitor that smoothes the voltage that has been boosted by the boosting circuit 92, and the second smoothing capacitor 60 is a pre-boosting smoothing that smoothes the voltage before the boosting by the boosting circuit 92. It is a capacitor.

2. Configuration of First Smoothing Capacitor On the outer surface of the capacitor main body 50a, which is the main body of the first smoothing capacitor 50, as shown in FIG. 1 and the like, a planar element arrangement surface S1, a first flat surface S4, and a second flat Plane S5. Here, as shown in FIGS. 4 and 5, the “main part” of the capacitor is a portion having an electrode (in this example, an internal electrode 54) and a dielectric portion 53 interposed between the electrodes, that is, a capacitor. It is a part that demonstrates its function. As shown in FIGS. 3 and 4, the first plane S4 is a plane that intersects the element arrangement plane S1 at the end of the element arrangement plane S1 on the −X direction side, which is one side in the X direction. The plane S5 is a surface that intersects the element arrangement surface S1 at the end of the element arrangement surface S1 on the + X direction side that is the other side in the X direction. The first plane S4 and the second plane S5 are formed to face in opposite directions. Here, “facing directions opposite to each other” for the two surfaces means that the inner product of the normal vectors going outward of the respective surfaces becomes negative, and the first plane S4 and the second plane S5 Including the case where the crossing each other. The element arrangement surface S1 is formed on the upper surface (the surface facing the + Z direction side) that is the outer surface on the upper side of the capacitor main body 50a. In the present embodiment, the capacitor body 50a has a rectangular parallelepiped outer shape, and each of the element arrangement surface S1, the first plane S4, and the second plane S5 is formed in a rectangular shape, and the first plane S4. And each of 2nd plane S5 is formed as a surface orthogonal to element arrangement | positioning surface S1. That is, in the present embodiment, the first plane S4 and the second plane S5 are formed as surfaces that face in opposite directions and are parallel to each other.

  As shown in FIGS. 1 to 3, the element arrangement surface S1 includes a positive electrode side connection electrode P1 and a negative electrode side connection electrode P2, and is electrically connected to at least one of the positive electrode side connection electrode P1 and the negative electrode side connection electrode P2. The switching element 10 can be arranged in a connected state. Each of the positive electrode side connection electrode P <b> 1 and the negative electrode side connection electrode P <b> 2 is an electrode (terminal connection electrode P) that is electrically connected to the terminal of the first smoothing capacitor 50. Specifically, the positive electrode side connection electrode P <b> 1 is an electrode electrically connected to the positive electrode terminal 51, and the negative electrode side connection electrode P <b> 2 is an electrode electrically connected to the negative electrode terminal 52. In the present embodiment, the switching element 10 and the diode element 20 constituting the series element unit 30 are arranged (in other words, mounted) on the element arrangement surface S1 while being electrically connected to the terminal connection electrode P. Yes. That is, in the present embodiment, the element arrangement surface S1 is configured such that the diode element 20 can be arranged in addition to the switching element 10. The switching element 10 and the diode element 20 are arranged (that is, placed) so as to be placed from the upper side with respect to the element arrangement surface S1 or the electrode formed on the element arrangement surface S1. The terminal connection electrode P formed on the element arrangement surface S1, and the inter-element connection electrode P3, the control electrode P4, and the discharge resistance electrode P5 (see FIG. 6) to be described later are made of, for example, a conductor foil (copper foil or the like) It can be a formed electrode. Moreover, such an electrode can be formed on the element arrangement surface S1 by using, for example, a printing technique.

  As described above, the element arrangement surface S1 has the positive electrode side connection electrode P1 electrically connected to the positive electrode terminal 51 as the terminal connection electrode P electrically connected to the terminals 51 and 52 of the first smoothing capacitor 50. And a negative electrode side connection electrode P2 electrically connected to the negative electrode terminal 52 is formed. In the present embodiment, as shown in FIG. 6, the discharge resistor electrode P5 having both a portion electrically connected to the positive electrode terminal 51 and a portion electrically connected to the negative electrode terminal 52 is provided in an element arrangement. It is formed on the surface S1. Each of the positive electrode side connection electrode P1 and the portion of the discharge resistance electrode P5 that is electrically connected to the positive electrode terminal 51 is one of the upper surface of the connection terminal 55 (see FIG. 4) electrically connected to the positive electrode terminal 51. By being formed so as to cover the part, it is electrically connected to the positive electrode terminal 51. In addition, each of the portions that are electrically connected to the negative electrode side connection electrode P2 and the negative electrode terminal 52 of the discharge resistance electrode P5 is formed so as to cover a part of the upper surface of the negative electrode terminal 52, whereby the negative electrode The terminal 52 is electrically connected.

  The positive electrode side connection electrode P1 and the negative electrode side connection electrode P2 are electrodes for electrically connecting the switching element 10 and the diode element 20 to the first smoothing capacitor 50. Therefore, in the present embodiment, a connection portion between the external electrode of the first smoothing capacitor 50 and the inverter circuit 91 side is formed by the upper surface of the connection terminal 55 and the upper surface of the negative electrode terminal 52. Although a detailed description is omitted, the connection portion of the external electrode of the first smoothing capacitor 50 to the DC power supply 3 side is also formed by the outer surface of the positive electrode terminal 51 or the connection terminal 55 or the outer surface of the negative electrode terminal 52. be able to.

  As shown in FIG. 6, in addition to the three electrodes P1, P2, and P5, an inter-element connection electrode P3 and a control electrode P4 are formed on the element arrangement surface S1. These electrodes P3 and P4 are electrodes that are electrically insulated from the terminals 51 and 52 of the first smoothing capacitor 50. Here, “electrically insulated” means electrically insulated on the element arrangement surface S1, and the first smoothing is performed via a circuit element, a wiring member, or the like arranged on the element arrangement surface S1. This is used as a concept including the case of being electrically connected to the terminals 51 and 52 of the capacitor 50.

  As shown in FIG. 6, in the present embodiment, the positive electrode side connection electrode P1 is formed so as to extend from the connection terminal 55 to the negative electrode terminal 52 side in the X direction (that is, the + X direction side) on the element arrangement surface S1. The negative electrode side connection electrode P2 is formed to extend on the element arrangement surface S1 from the negative electrode terminal 52 to the positive electrode terminal 51 side in the X direction (that is, the −X direction side). In the present embodiment, the positive electrode side connection electrode P1 does not have a portion arranged in the X direction between the negative electrode terminal 52 and the negative electrode side connection electrode P2 in the entire Y direction on the element arrangement surface S1. It is configured. Specifically, each of the positive electrode side connection electrode P1 and the negative electrode side connection electrode P2 is formed in a rectangular shape when viewed in the Z direction, and the length of the positive electrode side connection electrode P1 in the X direction and the negative electrode side connection electrode P2 are Each of the lengths in the X direction is set such that the positive electrode side connection electrode P1 and the negative electrode side connection electrode P2 are separated from each other in the X direction. And between the elements which electrically connect the switching element 10 and the diode element 20 constituting the series element unit 30 between the positive electrode side connection electrode P1 and the negative electrode side connection electrode P2 on the element arrangement surface S1 in the X direction. A connection electrode P3 is formed.

  In the present embodiment, the positive electrode side connection electrode P1, the negative electrode side connection electrode P2, and the inter-element connection electrode P3 are formed so as to have overlapping portions when viewed in the X direction, as shown in FIG. That is, three regions, a Y-direction region where the positive electrode side connection electrode P1 is formed, a Y direction region where the negative electrode side connection electrode P2 is formed, and a Y direction region where the inter-element connection electrode P3 is formed. There is a region in the Y direction included in all of the regions, and the inter-element connection electrode P3 is formed so as to be sandwiched from both sides in the X direction by the positive electrode side connection electrode P1 and the negative electrode side connection electrode P2. The inter-element connection electrode P3 is formed in a rectangular shape when viewed in the Z direction. In this example, as shown in FIG. 3, the inter-element connection electrode P <b> 3 is −Y with respect to the rectangular portion in the end region on the + X direction side where the second connection member 62 (described later) is disposed. It has a portion protruding in the direction side. In the present embodiment, a connecting member (not shown) connected to the coil of the rotating electrical machine 2 is connected to the protruding portion.

  The first smoothing capacitor 50 includes a positive terminal 51 that is a positive terminal and a negative terminal 52 that is a negative terminal. These terminals 51 and 52 function as terminals for inputting / outputting DC power to / from the DC power source 3 and the booster circuit 92 as shown in FIG. Also functions as a terminal for output. In the present embodiment, as shown in FIG. 4, the positive electrode terminal 51 uses a conductive material (for example, copper or the like) on the first plane S <b> 4 arranged at the end portion on the −X direction side of the first smoothing capacitor 50. The negative electrode terminal 52 is formed using a conductive material (for example, copper or the like) on the second plane S5 arranged at the end portion on the + X direction side of the first smoothing capacitor 50. In the present embodiment, the negative electrode terminal 52 is formed so as to be exposed on the upper surface of the capacitor body 50a. On the other hand, the upper part of the positive electrode terminal 51 is disposed below the upper surface of the capacitor body 50a, and the positive terminal 51 is not exposed on the upper surface of the capacitor body 50a. In the present embodiment, a connection terminal 55 is formed above the positive electrode terminal 51 in the first plane S4 via a separation part 56, and the connection terminal 55 is exposed on the upper surface of the capacitor body 50a. Is formed. That is, in the present embodiment, the upper surface of the capacitor body 50 a includes a portion formed by the upper end portion of the connection terminal 55 and a portion formed by the upper end portion of the negative electrode terminal 52. Furthermore, in this embodiment, each of the positive electrode terminal 51, the connection terminal 55, and the negative electrode terminal 52 is formed on the side surfaces on the both sides in the Y direction of the capacitor main body 50a (the outer surface on the side side), as shown in FIGS. ) To be exposed.

  In the present embodiment, the first smoothing capacitor 50 is a ceramic capacitor in which a dielectric portion 53 interposed between electrodes is formed of a ceramic material. This ceramic material is composed of, for example, barium titanate, strontium titanate, or alumina. Specifically, as schematically shown in FIGS. 4 and 5, the first smoothing capacitor 50 is a multilayer ceramic capacitor, and the dielectric portion 53 is stacked in the stacking direction (in the vertical direction here) via the internal electrode 54. It has a laminated structure. The internal electrode 54 is configured using one or more kinds of conductive materials (for example, copper or the like), and is formed so as to extend along the element arrangement surface S1. In the present embodiment, the internal electrode 54 is formed so as to extend in parallel to the element arrangement surface S1, and specifically, is a flat plate member parallel to the element arrangement surface S1. Inside the capacitor main body 50 a, as the internal electrodes 54, a positive side internal electrode 54 a electrically connected to the positive terminal 51 and a negative side internal electrode 54 b electrically connected to the negative terminal 52 are formed. The positive side internal electrodes 54a and the negative side internal electrodes 54b are alternately arranged in the stacking direction. The positive side internal electrode 54a is formed so as to extend from the positive terminal 51 to the + X direction side inside the capacitor main body 50a. The negative electrode side internal electrode 54 b is formed so as to extend from the negative electrode terminal 52 to the −X direction side inside the capacitor main body 50 a. That is, both the positive electrode terminal 51 and the negative electrode terminal 52 function as external electrodes, and are formed so as to extend at least over the entire arrangement region of the internal electrode 54 in the stacking direction of the first smoothing capacitor 50. 4 and 5, the number of stacked dielectric parts 53 is shown as “5”, but the actual number of stacked dielectric parts 53 can be set to an arbitrary value. For example, as the first smoothing capacitor 50, one having 100 or more dielectric portions 53 can be used.

  The element arrangement surface S1 formed on the outer surface of the capacitor main body 50a is formed integrally with the dielectric portion 53. Specifically, in the present embodiment, the upper surface of the capacitor main body 50a (specifically, the portion excluding the terminals 55 and 52) is the dielectric portion 53 disposed at the upper end inside the capacitor main body 50a. The lower surface (specifically, the portion excluding the terminals 51 and 52), which is the lower outer surface of the capacitor body 50a, is a dielectric portion disposed at the lower end inside the capacitor body 50a. 53. That is, in the present embodiment, the upper surface (specifically, the portion excluding the terminals 55 and 52 on the upper surface) of the capacitor main body 50a on which the element arrangement surface S1 is formed, and the lower surface (specifically, the upper surface of the capacitor main body 50a). (The portion excluding the terminals 51, 52 on the lower surface) is integrally formed of the same material as the dielectric portion 53. As the first smoothing capacitor 50, one manufactured using various known techniques can be employed. For example, as the first smoothing capacitor 50, a capacitor manufactured by low temperature co-firing using LTCC (Low Temperature Co-fired Ceramics) technology can be adopted. Further, when the dielectric portion 53 is configured using a ceramic material (for example, alumina), the first smoothing capacitor 50 is manufactured using a technique for firing the ceramic material (for example, the LTCC technique described above). Instead, it is also possible to adopt one produced using a technique (aerosol deposition technique) for forming a ceramic film by aerosolizing and spraying ceramic fine particles.

  An internal conductive layer 70 extending along the element arrangement surface S1 is provided inside the capacitor main body 50a. In the present embodiment, as shown in FIGS. 4 and 5, the internal conductive layer 70 is formed to extend in parallel to the element arrangement surface S1, and specifically, a flat plate shape parallel to the element arrangement surface S1. It is made a member. The internal conductive layer 70 is configured using one or a plurality of types of conductive materials (for example, copper). As described above, the internal electrode 54 is also configured using one or more types of conductive materials, and the same type of conductive material includes the conductive material constituting the internal conductive layer 70, and the internal electrode. 54 can be included in both of the conductive materials constituting 54. For example, the composition of the internal conductive layer 70 can be the same as that of the internal electrode 54. When the first smoothing capacitor 50 is manufactured using a technique of firing a ceramic material (for example, the LTCC technique described above), the melting point of the internal conductive layer 70 is the melting point of the dielectric portion 53. By forming the internal conductive layer 70 using a conductive material that is higher than that, the internal conductive layer 70 can be formed simultaneously with the internal electrode 54 when the dielectric portion 53 is formed by firing. It becomes possible.

  As shown in FIGS. 4 and 5, both the positive side internal electrode 54 a and the negative side internal electrode 54 b are on the side opposite to the element placement surface S <b> 1 with respect to the internal conductive layer 70 in the Z direction (that is, the internal conductive layer 70. (Lower side). That is, the internal conductive layer 70 is disposed above any internal electrode 54. Specifically, in the present embodiment, as shown in FIG. 4, the target internal electrode 54c, which is the internal electrode 54 disposed on the uppermost side of the plurality of internal electrodes 54, is configured by the positive-side internal electrode 54a. ing. The end region on the + X direction side of the target internal electrode 54c and the end region on the + X direction side of the internal conductive layer 70 disposed on the upper side of the target internal electrode 54c via the dielectric portion 53 are connected portions. 71 is electrically connected. In the present embodiment, the connection portion 71 is a plate-like member whose plate surface is parallel to a plane orthogonal to the X direction, and the lower end portion of the connection portion 71 is the end portion on the + X direction side of the target internal electrode 54c. And the upper end portion of the connecting portion 71 is connected to the end portion of the internal conductive layer 70 on the + X direction side. The connection portion 71 is configured using one or more types of conductive materials. The composition of the connection portion 71 may be the same as that of the internal conductive layer 70 or the internal electrode 54.

  The end region on the −X direction side of the internal conductive layer 70 is electrically connected to the positive electrode side connection electrode P1. Therefore, the positive electrode side connection electrode P <b> 1 is electrically connected to the positive electrode terminal 51 through the internal conductive layer 70. Specifically, in the present embodiment, as shown in FIG. 4, the connection terminal 55 is formed on the upper side of the positive electrode terminal 51 in the first plane S <b> 4 via the separation portion 56. The end portion of the internal conductive layer 70 on the −X direction side is connected to the connection terminal 55, and the exposed portion of the upper surface of the capacitor body 50a in the connection terminal 55 is connected to the positive electrode side connection electrode P1. ing. In addition, the isolation | separation part 56 is comprised using an electrically insulating material, and the connection terminal 55 is comprised using the electroconductive material. The composition of the connection terminal 55 can be the same as that of the positive electrode terminal 51. Further, the composition of the separation portion 56 can be the same as that of the dielectric portion 53. As shown in FIG. 7, the positive electrode terminal 51 is electrically connected to the positive electrode of the DC power supply 3, and the negative electrode terminal 52 is electrically connected to the negative electrode of the DC power supply 3. Therefore, in the ON state of the upper switching element 10a disposed on the element disposition surface S1 in a state of being electrically connected to the positive electrode side connection electrode P1, the target internal electrode 54c, the connection portion 71, and the internal conductivity are connected from the positive electrode terminal 51. Since the current flows through the positive electrode side connection electrode P1 through the layer 70 and the connection terminal 55 in the order described, the direction of the current flowing through the internal conductive layer 70 has a component in the −X direction as is apparent from FIG. Have. That is, as shown in FIG. 6, the internal conductive layer 70 is formed so that the current flow direction in the Z direction view has a component in the −X direction. In FIG. 6, the direction of current flow in the internal conductive layer 70 is conceptually represented by a dashed white arrow.

  Since the connection terminal 55 electrically connected to the positive electrode terminal 51 is connected to the end region on the −X direction side of the positive electrode side connection electrode P1, the connection terminal 55 is electrically connected to the positive electrode side connection electrode P1. The direction of the current flowing through the positive electrode side connection electrode P1 when the upper switching element 10a arranged on the element arrangement surface S1 is on has a component in the + X direction. That is, as shown in FIG. 6, the positive electrode side connection electrode P <b> 1 is formed so that the current flow direction as viewed in the Z direction has a component on the + X direction side. Further, since the negative electrode terminal 52 is connected to the end region on the + X direction side of the negative electrode side connection electrode P2, the lower stage arranged on the element arrangement surface S1 while being electrically connected to the negative electrode side connection electrode P2. The direction of the current flowing through the negative electrode side connection electrode P2 in the ON state of the side switching element 10b has a component in the + X direction. That is, as shown in FIG. 6, the negative electrode side connection electrode P2 is formed such that the current flow direction in the Z direction view has a component on the + X direction side. In FIG. 6, the direction of current flow in the positive electrode side connection electrode P1 is conceptually represented by a solid white arrow drawn on the positive electrode side connection electrode P1, and the current flow in the negative electrode side connection electrode P2 is shown. The direction is conceptually represented by a solid white arrow drawn overlapping the negative electrode side connection electrode P2.

  As described above, the current flow direction in the internal conductive layer 70 (that is, the direction having the component in the −X direction) is the current flow direction in the positive electrode side connection electrode P1 and the negative electrode side connection electrode P2 (that is, the + X direction direction). (The direction having the component). As a result, the magnetic field generated by the current flowing through the positive electrode side connection electrode P1 and the magnetic field generated by the current flowing through the negative electrode side connection electrode P2 are weakened or canceled by the magnetic field generated by the current flowing through the internal conductive layer 70. It is possible to reduce the effective inductance of the side connection electrode P1 and the negative side connection electrode P2. As a result, the surge voltage accompanying the switching operation of the switching element 10 can be suppressed.

  In the present embodiment, as shown in FIG. 6, the internal conductive layer 70 is formed so that the width of the internal conductive layer 70 in the Y direction is uniform along the X direction. That is, in the present embodiment, the shape of the internal conductive layer 70 as viewed in the Z direction is a rectangular shape. The internal conductive layer 70 is connected to the connection portion 71 and the connection terminal 55 so that the potential difference in the Y direction is negligible compared to the potential difference in the X direction. That is, in the present embodiment, the internal conductive layer 70 is formed such that the direction of current flow in the Z direction view matches the −X direction. Here, “match” means “match” in design. That is, the internal conductive layer 70 is formed according to a design in which the direction of current flow in the Z direction view matches the −X direction. Similarly, in the present embodiment, the positive electrode side connection electrode P1 and the negative electrode side connection electrode P2 are formed such that the current flow direction in the Z direction view matches the + X direction. In other words, the positive electrode side connection electrode P1 and the negative electrode side connection electrode P2 are formed in accordance with a design in which the current flow direction in the Z direction view matches the + X direction. In the present embodiment, the internal conductive layer 70 is further formed to extend in parallel to the element arrangement surface S1 on which the positive electrode side connection electrode P1 and the negative electrode side connection electrode P2 are formed. Therefore, in the present embodiment, the direction of the current flowing through the internal conductive layer 70 is a positional relationship parallel to the direction of the current flowing through the positive electrode side connection electrode P1 and the negative electrode side connection electrode P2, and The flow direction is opposite to the current flow direction in the positive electrode side connection electrode P1 and the negative electrode side connection electrode P2. Thereby, the effect of reducing the effective inductance of the positive electrode side connection electrode P1 and the negative electrode side connection electrode P2 can be enhanced.

  Further, in the present embodiment, as shown in FIG. 6, the internal conductive layer 70 is formed so as to have a portion overlapping with each of the positive electrode side connection electrode P1 and the negative electrode side connection electrode P2 when viewed in the Z direction. Yes. Thereby, the distance between the internal conductive layer 70 and the positive electrode side connection electrode P1 and the distance between the internal conductive layer 70 and the negative electrode side connection electrode P2 are shortened, and the positive electrode side connection electrode P1 and the negative electrode side connection electrode P1. It is possible to enhance the effect of reducing the effective inductance of P2. At this time, since the internal conductive layer 70 is formed inside the capacitor main body 50a, the electrical insulation between the internal conductive layer 70 and the positive electrode side connection electrode P1, the internal conductive layer 70 and the negative electrode side connection, or the like. The electrical insulation between the electrode P2 can be ensured by the dielectric portion 53 between the internal conductive layer 70 and the element arrangement surface S1. In the present embodiment, as shown in FIG. 6, the internal conductive layer 70 is further arranged in the element arrangement surface S1 in the element arrangement surface S1 (switching element arrangement region A) and in the element arrangement surface S1, as viewed in the Z direction. It is formed so as to have a portion overlapping with each of the arrangement region of the diode element 20 (diode element arrangement region B) and the inter-element connection electrode P3.

  In the present embodiment, as shown in FIG. 5, the internal conductive layer 70 is formed so that the width of the internal conductive layer 70 in the Y direction is narrower than the width of the internal electrode 54 in the Y direction. Specifically, in this embodiment, the width in the Y direction of the internal conductive layer 70 matches the width in the Y direction of the positive electrode side connection electrode P1, as shown in FIG. Thus, the effect of reducing the effective inductance is ensured by matching the width in the Y direction of the internal conductive layer 70 with the width in the Y direction of the effective inductance reduction target electrode (in this example, the positive electrode side connection electrode P1). However, the amount of the material constituting the internal conductive layer 70 can be reduced. Note that the width in the Y direction of the internal conductive layer 70 can be matched to the width in the Y direction of the negative electrode side connection electrode P2, which is an electrode for reducing the effective inductance, which is different from the positive electrode side connection electrode P1. In the present embodiment, as shown in FIG. 5, the width of the connecting portion 71 in the Y direction is uniform along the Z direction, and the width of the connecting portion 71 in the Y direction is Y of the internal conductive layer 70. Match the width of the direction.

3. Next, the arrangement configuration of the series element units 30 in the switching element unit 1 will be described. As shown in FIG. 3, in this embodiment, two series element units 30 of a first series element unit 30a and a second series element unit 30b are arranged on the element arrangement surface S1. And as shown in FIG. 7, the serial connection unit 33 of each of these two series element unit 30 is electrically connected, and the series element unit group 40 is comprised.

  As shown in FIG. 7, the series element unit 30 includes a positive electrode side terminal portion 31 connected to the positive electrode side of the DC power source 3 and a negative electrode side terminal portion connected to the negative electrode side (for example, the ground side) of the DC power source 3. 32. In the present embodiment, the positive terminal portion 31 of the series element unit 30 is electrically connected to the positive electrode of the DC power supply 3 via the switching element 10 and the reactor 82 that constitute the booster circuit 92. The boosted DC voltage is supplied to the positive terminal portion 31 of the series element unit 30.

  The series element unit set 40 constituted by the series element units 30 constitutes one arm set (a set of upper and lower arms, in other words, a leg) of the inverter circuit 91 that converts a DC voltage into an AC voltage. . A plurality of series element units 30 constituting the same arm set are provided in the same switching element unit 1. In the present embodiment, two series element units 30 constituting one arm set are provided in the same switching element unit 1 and arranged on the same element arrangement surface S1. That is, in this embodiment, the switching element unit 1 includes one series element unit set 40.

  In this embodiment, as shown in FIG. 7, the rotating electrical machine 2 to which AC voltage is supplied is an AC motor driven by a three-phase AC, and each of the three phases (U phase, V phase, W phase). A total of three corresponding arm groups are electrically connected in parallel to form an inverter circuit 91. That is, in this embodiment, in addition to the switching element unit 1 including the U-phase series element unit set 40U, the switching element unit including the V-phase series element unit set 40V and the switching element unit including the W-phase series element unit set 40W Is used to form an inverter circuit 91. The V-phase series element unit set 40V and the W-phase series element unit set 40W are different from each other in the connection relationship with the rotating electrical machine 2 (specifically, the phase of the coil to be connected is different). Since the configuration is the same as that of the unit set 40U, the illustration of the switching element unit including the V-phase series element unit set 40V and the switching element unit including the W-phase series element unit set 40W is omitted here.

  Thus, in this embodiment, the inverter circuit 91 is formed using three switching element units, and one first smoothing capacitor 50 is electrically connected to each arm set (each series element unit set 40). Connected in parallel. FIG. 7 shows an example in which one first smoothing capacitor 50 is connected to all three arm groups in order to avoid complication. The rotating electrical machine 2 to be controlled by the inverter circuit 91 can be, for example, a rotating electrical machine provided as a driving force source for wheels in an electric vehicle, a hybrid vehicle, or the like. In the specification of the present application, the “rotary electric machine” is used as a concept including a motor (electric motor), a generator (generator), and a motor / generator functioning as both a motor and a generator as necessary.

  As shown in FIG. 7, the positive electrode side terminal portion 31 of the series element unit 30 is electrically connected to the positive electrode side connection electrode P <b> 1 (see FIG. 6), thereby being electrically connected to the positive electrode terminal 51 of the first smoothing capacitor 50. Connected. In the present embodiment, the positive terminal portion 31 is electrically connected to the positive terminal 51 via the connection terminal 55. Further, the negative electrode side terminal portion 32 of the series element unit 30 is electrically connected to the negative electrode terminal 52 of the first smoothing capacitor 50 by being electrically connected to the negative electrode side connection electrode P2 (see FIG. 6). Yes. The intermediate connection portions 33 of a plurality (two in this example) of the series element units 30 constituting the same series element unit set 40 are electrically connected to each other and connected to coils of corresponding phases. ing. Hereinafter, the configuration of the switching element unit 1 for realizing such an electrical connection configuration will be described.

  Both the first series element unit 30a and the second series element unit 30b are configured such that the switching element 10 and the diode element 20 are electrically connected in series with each other. As shown in FIG. The arrangement configuration of the element 10 and the diode element 20 is different between the first series element unit 30a and the second series element unit 30b. Specifically, when the element disposed on the positive electrode side in the series element unit 30 is defined as “positive electrode side element” and the element disposed on the negative electrode side is defined as “negative electrode side element”, the positive electrode of the first series element unit 30a. The side element is the switching element 10, whereas the positive side element of the second series element unit 30 b is the diode element 20. The negative element on the first series element unit 30 a is the diode element 20, whereas the negative element on the second series element unit 30 b is the switching element 10.

  And if the connection part (in other words, connection part of the switching element 10 and the diode element 20) of the positive electrode side element and negative electrode side element which comprise the serial element unit 30 is used as the intermediate | middle connection part 33, it will be 1st serial element unit. The intermediate connection portions 33 of the 30a and the second series element unit 30b are electrically connected to each other. Therefore, the element set of the positive side element of the first series element unit 30a and the positive side element of the second series element unit 30b that are electrically connected in parallel with each other, and the first set that is electrically connected in parallel with each other. It can be said that the element group of the negative electrode side element of the series element unit 30a and the negative electrode side element of the second series element unit 30b is electrically connected to each other in series to form the series element unit set 40. That is, the switching element 10 and the diode element 20 arranged in the upper arm in the inverter circuit shown in FIG. 7 are respectively the upper stage switching element 10a and the upper stage diode element 20a, and the switching element 10 and the diode arranged in the lower arm. Assuming that the elements 20 are a lower-stage switching element 10b and a lower-stage diode element 20b, respectively, the upper-stage switching element 10a and the lower-stage diode element 20b are electrically connected in parallel. The lower switching elements 10b connected in parallel are electrically connected to each other in series to form a series element unit set 40.

  As shown in FIG. 3, in the present embodiment, the upper stage side switching element 10a is arranged on the −Y direction side with respect to the lower stage side diode element 20b, and the lower stage side switching element 10b is −Y than the upper stage side diode element 20a. It is arranged on the direction side. That is, each of the plurality of switching elements 10 included in the same series element unit set 40 is disposed on the same side in the Y direction with respect to the diode elements 20 constituting the same series element unit 30. The plurality of switching elements 10 (in this example, the upper stage switching element 10a and the lower stage switching element 10b) included in the same series element unit set 40 are arranged on the element arrangement surface S1 so as to be aligned in the X direction. In the present embodiment, as shown in FIG. 6, the element arrangement surface S1 is formed in a rectangular shape having a long side and a short side, the X direction is parallel to the extending direction of the long side, and the Y direction is short. It is parallel to the extending direction of the side. The diode element 20 electrically connected in parallel to the switching element 10 is arranged on the element arrangement surface S1 so as to be aligned with the switching element 10 in the Y direction. Specifically, the upper diode element 20a is disposed adjacent to the + Y direction side of the upper switching element 10a, and the lower diode element 20b is adjacent to the + Y direction side of the lower switching element 10b. Are arranged. Here, “adjacently arranged” means that no other circuit element is arranged between the switching element 10 and the diode element 20 in the extending direction (here, the Y direction) of the element arrangement surface S1. In addition, the concept includes both a state in which the separation distance between the switching element 10 and the diode element 20 is zero (that is, a state in which the outer surfaces are in contact with each other) and a state in which the separation distance is greater than zero. It is used as

  As described above, since the upper stage side switching element 10a, the lower stage side switching element 10b, the upper stage side diode element 20a, and the lower stage side diode element 20b are arranged, in this embodiment, as shown in FIG. The switching element 10a is disposed on the −X direction side with respect to the lower stage side diode element 20b, and the upper stage side diode element 20a is disposed on the −X direction side with respect to the lower stage side switching element 10b. That is, in the present embodiment, for each of the first series element unit 30a and the second series element unit 30b, either the switching element 10 or the diode element 20 constituting the series element unit 30 is disposed on the positive electrode side. The element is disposed on the −X direction side (that is, on the positive electrode terminal 51 side in the X direction) than the negative electrode side element disposed on either negative electrode side.

  As shown in FIGS. 4 and 5, the switching element 10 has a pair of main terminals 12 and 13 and a control terminal 11. The main terminals 12 and 13 are terminals electrically connected to a DC voltage supply source (DC power supply 3 in this example). Here, of the pair of main terminals 12 and 13, the high-potential side terminal is the positive-side main terminal 12, and the low-potential side terminal is the negative-side main terminal 13. As shown in FIGS. 5 and 7, in the upper diode element 20a, the cathode terminal 22 is electrically connected to the positive main terminal 12 of the upper switching element 10a, and the negative main terminal 13 of the upper switching element 10a. The anode terminal 21 is electrically connected to the upper switching element 10a in an antiparallel relationship so that the anode terminal 21 is electrically connected to the anode terminal 21. Similarly, the lower diode element 20b is electrically connected to the lower switching element 10b in an antiparallel relationship. That is, the diode element 20 functions as an FWD (Free Wheel Diode). The control terminal 11 is a control terminal for controlling on / off of the switching element 10. When the switching element 10 is in an on state, the positive side main terminal 12 and the negative side main terminal 13 are electrically connected, and the switching element 10 is turned off. In the state, conduction between the positive-side main terminal 12 and the negative-side main terminal 13 is interrupted.

  As shown in FIGS. 4, 5, and 7, the positive main terminal 12 of the upper switching element 10a constitutes the positive terminal 31 of the first series element unit 30a, and the anode of the lower diode element 20b. The terminal 21 constitutes the negative electrode side terminal portion 32 of the first series element unit 30a. Further, the negative main terminal 13 of the lower switching element 10b constitutes the negative terminal part 32 of the second series element unit 30b, and the cathode terminal 22 of the upper diode element 20a is the positive terminal of the second series element unit 30b. The side terminal part 31 is comprised.

  In the present embodiment, as shown in FIG. 7, the switching element 10 is an IGBT (insulated gate bipolar transistor), the positive-side main terminal 12 is configured by a collector terminal, and the negative-side main terminal 13 is configured by an emitter terminal. The control terminal 11 is composed of a gate terminal. The control terminal 11 is electrically connected to a control unit (not shown) via a gate resistor 83 (see FIGS. 3 and 5), and each switching element 10 corresponds to a gate voltage applied to the control terminal 11. Switching control is individually performed. As the switching element 10, a MOSFET (metal oxide semiconductor field effect transistor) or the like can be used.

  As shown in FIG. 5, each of the positive-side main terminal 12 and the negative-side main terminal 13 is separately formed on the outer surfaces facing the opposite sides of the switching element 10 whose outer shape is formed in a rectangular parallelepiped shape. Specifically, the switching element 10 has an outer surface on which the positive-side main terminal 12 is formed and an outer surface on which the negative-side main terminal 13 is formed, and these two outer surfaces are opposite to each other and are mutually opposite. It is formed as a parallel surface. And the switching element 10 is arrange | positioned at the element arrangement | positioning surface S1 so that the outer surface in which the negative electrode side main terminal 13 was formed becomes the 1st opposing arrangement | positioning surface S2 which opposes element arrangement | positioning surface S1. That is, in the state where the switching element 10 is arranged on the element arrangement surface S <b> 1, the positive side main terminal 12 is arranged on the upper surface of the switching element 10, and the negative side main terminal 13 is arranged on the lower surface of the switching element 10. And in this embodiment, the control terminal 11 is arrange | positioned on the outer surface of the switching element 10 in which the negative electrode side main terminal 13 is formed with the said negative electrode side main terminal 13 spaced apart by the insulation distance. That is, in the present embodiment, the main terminals 12 and 13 (specifically, the negative side main terminal 13) are formed on the first opposing arrangement surface S2 of the switching element 10, and further in the present embodiment, the first terminal A control terminal 11 is also formed on the one opposing arrangement surface S2.

  The switching element 10 is arranged on the element arrangement surface S1 so that the first facing arrangement surface S2 and the element arrangement surface S1 are in contact directly or via a bonding member. In addition, the electrode formed in the said element arrangement | positioning surface S1 is contained in the element arrangement | positioning surface S1 in the case of "it contact | abuts with the element arrangement | positioning surface S1 directly or through a joining member. Specifically, as shown in FIGS. 3 to 5, the upper switching element 10 a is arranged so as to be placed on the inter-element connection electrode P <b> 3 through the bonding material 93 from above, and the upper diode element 20 a is also Further, it is arranged so as to be placed on the inter-element connection electrode P3 through the bonding material 93 from above. As shown in FIG. 5, in this example, an anode terminal 21 is formed on the lower surface of the diode element 20, and a cathode terminal 22 is formed on the upper surface of the diode element 20. That is, the diode element 20 is arranged on the element arrangement surface S1 so that the outer surface on which the anode terminal 21 is formed becomes the second opposite arrangement surface S3 facing the element arrangement surface S1, and the second opposite arrangement surface S3. And the element arrangement surface S1 are in contact with each other directly or via a bonding member. The bonding material 93 as the bonding member is made of a conductive material such as solder or conductive paste. As a result, the negative main terminal 13 formed on the lower surface of the upper switching element 10a and the anode terminal 21 formed on the lower surface of the upper diode element 20a are electrically connected to the inter-element connection electrode P3. Is done.

  The lower stage side switching element 10b is arranged so as to be placed on the negative electrode side connection electrode P2 via the bonding material 93 from above, and the lower stage side diode element 20b is also arranged on the negative electrode side connection electrode P2 via the bonding material 93 from above. It is arranged to be placed. Thus, the negative main terminal 13 formed on the lower surface of the lower switching element 10b and the anode terminal 21 formed on the lower surface of the lower diode element 20b are electrically connected to the negative connection electrode P2. Is done. That is, the lower stage side switching element 10b and the lower stage side diode element 20b are arranged on the element arrangement surface S1 in a state of being electrically connected to the negative electrode side connection electrode P2. The negative electrode side connection electrode P2 is electrically connected to the negative electrode terminal 52, and the negative electrode side main terminal 13 of the lower stage side switching element 10b and the anode terminal 21 of the lower stage side diode element 20b are connected to the negative electrode side connection electrode. It is electrically connected to the negative terminal 52 through P2. Thus, the negative electrode side connection electrode P2 includes the negative electrode side terminal portion 32 of the first series element unit 30a constituted by the anode terminal 21 of the lower diode element 20b, and the negative electrode main terminal 13 of the lower switch element 10b. This is an electrode for electrically connecting the negative electrode side terminal portion 32 of the second series element unit 30b constituted by the negative electrode terminal 52 of the first smoothing capacitor 50.

  As shown in FIGS. 1 and 2, the positive main terminal 12 (see FIGS. 4 and 5) formed on the upper surface of the upper switching element 10a and the cathode terminal 22 formed on the upper surface of the upper diode element 20a. Are electrically connected to the positive electrode side connection electrode P1, and the conductive first connection member 61 is disposed. That is, the first connection member 61 electrically connects the positive electrode side connection electrode P1 and the upper stage side switching element 10a, and electrically connects the positive electrode side connection electrode P1 and the upper stage side diode element 20a. Specifically, as shown in FIG. 4, the first connection member 61 includes a first portion 61 a disposed so as to be placed on the positive electrode side connection electrode P <b> 1 from above via the bonding material 93, and the bonding material 93. A second portion 61b disposed on the upper stage side switching element 10a and the upper stage side diode element 20a so as to be placed from above. Thereby, the positive side main terminal 12 of the upper stage side switching element 10a and the cathode terminal 22 of the upper stage side diode element 20a are electrically connected to the positive electrode side connection electrode P1. That is, the upper stage side switching element 10a and the upper stage side diode element 20a are arranged on the element arrangement surface S1 in a state of being electrically connected to the positive electrode side connection electrode P1. The positive electrode side connection electrode P1 is electrically connected to the positive electrode terminal 51, and the positive electrode side main terminal 12 of the upper stage side switching element 10a and the cathode terminal 22 of the upper stage side diode element 20a are connected to the positive electrode side connection electrode. It is electrically connected to the positive terminal 51 through P1. Thus, the positive electrode side connection electrode P1 includes the positive electrode side terminal portion 31 of the first series element unit 30a configured by the positive electrode side main terminal 12 of the upper stage side switching element 10a and the cathode terminal 22 of the upper stage side diode element 20a. This is an electrode for electrically connecting the positive terminal portion 31 of the second series element unit 30b constituted by the positive terminal 51 of the first smoothing capacitor 50.

  As shown in FIGS. 1 and 2, the positive main terminal 12 (see FIG. 4) formed on the upper surface of the lower switching element 10b and the cathode terminal 22 formed on the upper surface of the lower diode element 20b. Is electrically connected to the inter-element connection electrode P3. The conductive second connection member 62 is disposed. That is, the second connection member 62 electrically connects the inter-element connection electrode P3 and the lower-stage switching element 10b, and electrically connects the inter-element connection electrode P3 and the lower-stage diode element 20b. Specifically, as shown in FIG. 4, the second connection member 62 includes a first portion 62 a disposed so as to be placed on the inter-element connection electrode P <b> 3 from above via the bonding material 93, and the bonding material 93. A second portion 62b disposed on the lower stage side switching element 10b and the lower stage side diode element 20b so as to be placed from above. As a result, the positive main terminal 12 of the lower switching element 10b and the cathode terminal 22 of the lower diode element 20b are electrically connected to the inter-element connection electrode P3. As a result, the negative main terminal 13 of the upper switching element 10a and the anode terminal 21 of the upper diode element 20a are connected to the positive main terminal 12 and lower diode of the lower switching element 10b via the inter-element connection electrode P3. It is electrically connected to the cathode terminal 22 of the element 20b. Thus, the inter-element connection electrode P3 is between the switching element 10 and the diode element 20 constituting the series element unit 30 (specifically, between the upper stage side switching element 10a and the lower stage side diode element 20b, and A plurality of series element units constituting the same series element unit set 40 as well as electrodes for electrically connecting the upper stage side diode element 20a and the lower stage side switching element 10b) to form the intermediate connection portion 33. This is an electrode for connecting the 30 intermediate connection portions 33 to each other.

  In the present embodiment, as shown in FIGS. 1 and 4, the first connection member 61 and the second connection member 62 have a flat portion on the upper surface. And although illustration is abbreviate | omitted, the heat sink is arrange | positioned through the insulating member above this flat part. This insulating member has both electrical insulation and thermal conductivity. Accordingly, it is possible to efficiently transfer the heat of the switching element 10 to the heat sink via the connection members 61 and 62 while ensuring electrical insulation between the switching element 10 and the heat sink. Thus, the connection members 61 and 62 have a function as a heat spreader in addition to the function as a connection member (bus bar).

  The control electrode P4 is a control electrode that is electrically connected to the control terminal 11. Specifically, as shown in FIG. 5, the control electrode P4 is disposed below the control terminal 11 and electrically connected to the control terminal 11, and the part is on the −Y direction side. The gate resistor 83 is placed from above so as to electrically connect the two parts. Although not shown, a connection terminal of a flexible printed circuit board is formed in the separated portion, and the control terminal 11 generates a switching control signal (a gate drive signal in this example) via the flexible printed circuit board. Is electrically connected to a control unit (not shown). The flexible printed circuit board is a printed circuit board that is flexible and can be greatly deformed.

  In addition, the discharge resistance electrode P5 is an electrode for disposing a discharge resistance 81 (see FIG. 7) that is electrically connected to the first smoothing capacitor 50 in parallel. Specifically, as shown in FIG. 6, the discharge resistance electrode P5 is electrically connected to the positive electrode terminal 51 and the negative electrode terminal 52, which are two parts separated from each other in the X direction. Connected portions. And as shown in FIG. 1, the discharge resistance 81 is arrange | positioned so that it may mount from an upper side so that these two parts may be electrically connected.

4). Other Embodiments Finally, other embodiments of the smoothing capacitor according to the present invention will be described. Note that the configurations disclosed in the following embodiments can be applied in combination with the configurations disclosed in other embodiments as long as no contradiction arises.

(1) In the above embodiment, the end regions on the + X direction side of the internal conductive layer 70 and the target internal electrode 54c are electrically connected to each other, and the −X direction end of the internal conductive layer 70 The configuration in which the partial region is electrically connected to the positive electrode side connection electrode P1 and the positive electrode side connection electrode P1 is electrically connected to the positive electrode terminal 51 via the internal conductive layer 70 has been described as an example. However, the embodiment of the present invention is not limited to this. For example, as shown in FIGS. 8 and 9, the end regions on the −X direction side of the internal conductive layer 70 and the target internal electrode 54 c are electrically connected via a connection portion 71, An end region on the + X direction side of the conductive layer 70 is electrically connected to the negative electrode side connection electrode P2, and the negative electrode side connection electrode P2 is electrically connected to the negative electrode terminal 52 via the internal conductive layer 70. It is also possible. In this configuration, unlike the above embodiment, the target internal electrode 54c, which is the uppermost internal electrode 54 of the plurality of internal electrodes 54, is not connected to the positive side internal electrode 54a but to the negative side internal electrode 54b. Configure.

  Specifically, in the configuration shown in FIGS. 8 and 9, the positive terminal 51 is formed so as to be exposed on the upper surface of the capacitor body 50a. On the other hand, the upper portion of the negative electrode terminal 52 is disposed below the upper surface of the capacitor body 50a. A connection terminal 55 is formed on the upper side of the negative electrode terminal 52 in the second plane S5 via a separation part 56, and the connection terminal 55 is formed so as to be exposed on the upper surface of the capacitor body 50a. The end of the internal conductive layer 70 on the + X direction side is connected to the connection terminal 55, and the exposed portion of the upper surface of the capacitor body 50a in the connection terminal 55 is connected to the negative electrode side connection electrode P2. Yes. Therefore, in this example, when the lower switching element 10b disposed on the element disposition surface S1 is electrically connected to the negative electrode side connection electrode P2, the connection terminal 55, the internal Since the current flows through the negative electrode terminal 52 through the conductive layer 70, the connection portion 71, and the target internal electrode 54c in the order described, the direction of the current flowing through the internal conductive layer 70 is −X as is apparent from FIG. Has a directional component. That is, also in this example, as shown in FIG. 9, the internal conductive layer 70 is formed such that the current flow direction in the Z direction has a component in the −X direction. In the example shown in FIG. 9, unlike the above embodiment, the internal conductive layer 70 has a width in the Y direction that matches the width in the Y direction of the negative electrode side connection electrode P2 instead of the positive electrode side connection electrode P1. A conductive layer 70 is formed.

(2) In the above embodiment, the configuration in which the switching element unit 1 includes one series element unit set 40 has been described as an example. However, the embodiment of the present invention is not limited to this. That is, the switching element unit 1 can be configured to include a plurality of series element unit sets 40. For example, as illustrated in FIG. 10, the switching element unit 1 may include two series element unit sets 40. In this example, the switching element unit 1 includes a V-phase series element unit set 40V in addition to the U-phase series element unit set 40U. As shown in FIG. 7, the V-phase series element unit set 40 </ b> V is configured in the same manner as the U-phase series element unit set 40 </ b> U except that the phases of coils to be connected to the intermediate connection portion 33 are different. That is, the third series element unit 30c constituting the V-phase series element unit set 40V is configured similarly to the first series element unit 30a constituting the U-phase series element unit set 40U, and the V-phase series element unit set 40V. The fourth series element unit 30d constituting the same is configured in the same manner as the second series element unit 30b constituting the U-phase series element unit set 40U.

  As shown in FIG. 10, the V-phase series element unit set 40V is arranged side by side on the + Y direction side with respect to the U-phase series element unit set 40U. That is, it can be said that the switching element unit 1 according to this example has a configuration in which two switching element units 1 (see FIG. 3) according to the first embodiment are arranged in the Y direction. Therefore, the internal conductive layer 70 is provided separately for each of the U-phase series element unit set 40U and the V-phase series element unit set 40V. The U-phase series element unit set 40U and the V-phase series element unit set are formed by making the shape of the internal conductive layer 70 viewed in the Z direction to be the smallest rectangular shape including both of the two internal conductive layers 70 in FIG. A common internal conductive layer 70 may be provided for 40V. In FIG. 10, portions related to the discharge resistor 81 and the gate resistor 83 are not shown in order to avoid complexity. In this configuration, since one first smoothing capacitor 50 is electrically connected in parallel to two arm sets (two series element unit sets 40), the capacity of the first smoothing capacitor 50 in this example is This is twice that of the first embodiment.

(3) In the above embodiment, the internal conductive layer 70 is described as an example of a configuration in which the internal conductive layer 70 is formed so as to have a portion overlapping with each of the positive electrode side connection electrode P1 and the negative electrode side connection electrode P2 when viewed in the Z direction. did. However, the embodiment of the present invention is not limited to this. That is, the internal conductive layer 70 may be configured to have a portion overlapping with only one of the positive electrode side connection electrode P1 and the negative electrode side connection electrode P2 when viewed in the Z direction. In this case, it is also possible to adopt a configuration in which a plurality of internal conductive layers 70 are provided inside the capacitor main body 50a. For example, as the internal conductive layer 70, a first internal conductive layer formed so as to have a portion overlapping only with the positive electrode side connection electrode P1 of the positive electrode side connection electrode P1 and the negative electrode side connection electrode P2 as viewed in the Z direction; The second internal conductive layer is formed so as to have a portion overlapping only with the negative electrode side connection electrode P2 of the positive electrode side connection electrode P1 and the negative electrode side connection electrode P2 when viewed in the Z direction. be able to. In addition, the internal conductive layer 70 is formed at a position where neither the positive electrode side connection electrode P1 nor the negative electrode side connection electrode P2 has an overlapping portion when viewed in the Z direction, that is, the positive electrode side connection electrode P1 and the negative electrode. It is also possible to adopt a configuration formed at a position different from any of the side connection electrodes P2.

(4) In the above embodiment, the internal conductive layer 70 is formed so as to have a portion overlapping with each of the switching element arrangement region A, the diode element arrangement region B, and the inter-element connection electrode P3 when viewed in the Z direction. The above configuration has been described as an example. However, the embodiment of the present invention is not limited to this. That is, the configuration in which the internal conductive layer 70 is formed at a position that does not overlap with at least one of the switching element arrangement region A, the diode element arrangement region B, and the inter-element connection electrode P3 when viewed in the Z direction. That is, it is also possible to adopt a configuration formed at a position different from at least one of these.

(5) In the above embodiment, the Y-direction width of the internal conductive layer 70 matches the Y-direction width of the terminal connection electrode P (specifically, the positive-side connection electrode P1) whose effective inductance is to be reduced. Was described as an example. However, the embodiment of the present invention is not limited to this. For example, the internal conductive layer 70 may be configured such that the width in the Y direction of the internal conductive layer 70 is larger than the width in the Y direction of the electrode whose effective inductance is to be reduced. In this case, for example, the width of the internal conductive layer 70 in the Y direction can be matched with the width of the internal electrode 54 in the Y direction.

(6) In the above embodiment, the configuration in which the width in the Y direction of the internal conductive layer 70 is uniform along the X direction has been described as an example. However, the embodiment of the present invention is not limited to this. In other words, the internal conductive layer 70 may be configured such that the width in the Y direction of the internal conductive layer 70 varies depending on the position in the X direction. For example, in the example shown in FIG. 6, in the region in the X direction that overlaps the positive electrode side connection electrode P <b> 1 when viewed in the Z direction, the width in the Y direction of the internal conductive layer 70 matches the width in the Y direction of the positive electrode side connection electrode P <b> 1. In the region in the X direction that overlaps with the negative electrode side connection electrode P2 when viewed in the Z direction, the internal conductive layer 70 is formed so that the Y direction width of the internal conductive layer 70 matches the Y direction width of the negative electrode side connection electrode P2. Can be configured.

(7) In the above embodiment, the configuration in which the internal conductive layer 70 is formed so that the current flow direction in the Z direction view matches the −X direction has been described as an example. However, the embodiment of the present invention is not limited to this. That is, the current flow direction in the internal conductive layer 70 may be inclined with respect to the X direction as viewed in the Z direction.

(8) In the above-described embodiment, the configuration in which the internal conductive layer 70 is formed to extend in parallel to the element arrangement surface S1 has been described as an example. However, the embodiment of the present invention is not limited to this. That is, the internal conductive layer 70 may be configured to extend in a direction intersecting the element arrangement surface S1. In this case, the crossing angle is preferably set to, for example, an angle of 5 degrees or less.

(9) In the above embodiment, the connection terminal 55 is formed above the positive electrode terminal 51 in the first plane S4 via the separation part 56, and the connection terminal 55 is exposed on the upper surface of the capacitor body 50a. The configuration formed in the above has been described as an example. However, the embodiment of the present invention is not limited to this. For example, the connection terminal 55 to which the end portion on the −X direction side of the internal conductive layer 70 is connected can be formed to be shifted to the + X direction side with respect to the positive electrode terminal 51. In this case, in addition to the connection terminal 55, the positive electrode terminal 51 can also be configured to be exposed on the upper surface of the capacitor main body 50a. Even in such a configuration, by forming the positive electrode side connection electrode P1 only in the region on the + X direction side of the positive electrode terminal 51 so as not to cover the upper surface of the positive electrode terminal 51, similarly to the above embodiment, The internal conductive layer 70 can be formed such that the current flow direction in the Z direction has a component in the −X direction.

(10) In the above embodiment, the configuration in which the first smoothing capacitor 50 is a ceramic capacitor in which the dielectric portion 53 interposed between the electrodes is formed of a ceramic material has been described as an example. However, the embodiment of the present invention is not limited to this. That is, the dielectric portion 53 of the first smoothing capacitor 50 may be made of a material other than a ceramic material (for example, a synthetic resin).

(11) In the above embodiment, the configuration in which the element arrangement surface S1 is formed of the same material as that of the dielectric portion 53 has been described as an example. However, the embodiment of the present invention is not limited to this. That is, the element arrangement surface S1 may be formed of a material different from that of the dielectric portion 53. In the above-described embodiment, the configuration in which an even number of series element units 30 are arranged on the element arrangement surface S1 has been described as an example. However, an odd number (for example, one, three, etc.) of series element units 30 is an element. It is also possible to adopt a configuration arranged on the arrangement surface S1.

(12) In the above embodiment, the switching element 10 is arranged on the element arrangement surface S1 such that the outer surface on which the negative electrode side main terminal 13 is formed becomes the first opposed arrangement surface S2 that faces the element arrangement surface S1. The above configuration has been described as an example. However, the embodiment of the present invention is not limited to this. That is, the configuration in which the switching element 10 is arranged on the element arrangement surface S1 such that the outer surface on which the positive-side main terminal 12 is formed becomes the first opposing arrangement surface S2 facing the element arrangement surface S1, that is, the switching element It is also possible to adopt a configuration in which the negative side main terminal 13 is arranged on the upper surface of the switching element 10 and the positive side main terminal 12 is arranged on the lower surface of the switching element 10 in a state where 10 is arranged on the element arrangement surface S1. is there. In this case, in the example shown in FIG. 4 according to the above embodiment, the terminal indicated by reference numeral 52 is a positive terminal, and the terminal indicated by reference numeral 51 is a negative terminal. Also, in the example shown in FIG. 8 according to the other embodiment (1), the terminal indicated by reference numeral 52 is a positive electrode terminal, and the terminal indicated by reference numeral 51 is a negative electrode terminal. In these cases, all the three white arrows representing the current flow in FIGS. 6 and 9 are reversed, but the current flow direction in the Z direction in the internal conductive layer 70 is the same as in the above embodiment. In the same manner as the above, a component in a direction from the negative electrode terminal toward the positive electrode terminal in the reference direction X is included.

(13) In the above embodiment, the configuration in which the control terminal 11 is formed on the first facing arrangement surface S2 of the switching element 10 has been described as an example. However, the embodiment of the present invention is not limited to this. That is, it is also possible to adopt a configuration in which the control terminal 11 is formed on the outer surface (for example, the upper surface which is the upper outer surface) other than the first facing surface S2 in the switching element 10. In this case, for example, the control terminal 11 can be electrically connected to the control electrode P4 via a wire member. In this case, the control electrode P4 is not formed on the element arrangement surface S1, and the control unit 11 generates a switching control signal (a gate drive signal in this example) without the element arrangement surface S1 being interposed. It is also possible to adopt a configuration that is electrically connected to (not shown).

(14) In the above embodiment, the diode element 20 electrically connected in parallel to the switching element 10 has been described as an example of a configuration in which the diode element 20 is disposed on the element arrangement surface S1 adjacent to the switching element 10. . However, the embodiment of the present invention is not limited to this. That is, another circuit element may be arranged between the switching element 10 and the diode element 20 that are electrically connected in parallel with each other in the extending direction of the element arrangement surface S1. In addition, the diode element 20 may be arranged on the outer surface (for example, the lower surface) other than the element arrangement surface S1 of the first smoothing capacitor 50, or may be arranged on a member different from the first smoothing capacitor 50. Is possible. That is, the element arrangement surface S <b> 1 can be configured such that only the switching element 10 of the switching element 10 and the diode element 20 can be arranged.

(15) In the above embodiment, the inverter circuit 91 is a DC / AC conversion circuit that converts a DC voltage into a three-phase AC voltage, and the configuration in which the inverter circuit 91 includes six switching elements 10 has been described as an example. However, the embodiment of the present invention is not limited to this. For example, the inverter circuit 91 may be a DC / AC conversion circuit that converts a DC voltage into a single-phase AC voltage, and the inverter circuit 91 may include four switching elements 10.

(16) In the above embodiment, the case where the smoothing capacitor according to the present invention is applied to the inverter circuit 91 (see FIG. 7) for controlling the rotating electrical machine 2 has been described as an example. However, the embodiment of the present invention is not limited to this. That is, the smoothing capacitor according to the present invention can be applied to other circuits such as the booster circuit 92. When applied to the booster circuit 92, for example, an element arrangement surface is formed by the switching element 10 and the diode element 20 constituting the booster circuit 92 on the outer surface of the second smoothing capacitor 60 as the smoothing capacitor according to the present invention. It can be set as the structure formed so that arrangement | positioning of the serial element unit to be performed was possible. Although details are omitted, such a configuration can be configured in the same manner as in the above embodiment, except that the element arrangement surface S1 in the above embodiment is replaced with the element arrangement surface of the second smoothing capacitor 60.

(17) In the above-described embodiment, the rotating electric machine drive circuit that drives the rotating electric machine 2 has been described as an example in which the booster circuit 92 is provided in addition to the inverter circuit 91. However, the embodiment of the present invention is not limited to this. That is, the rotating electrical machine drive circuit that drives the rotating electrical machine 2 may be configured not to include the booster circuit 92.

(18) Regarding other configurations as well, the embodiments disclosed herein are illustrative in all respects, and the embodiments of the present invention are not limited thereto. In other words, configurations that are not described in the claims of the present application can be modified as appropriate without departing from the object of the present invention.

  INDUSTRIAL APPLICABILITY The present invention can be suitably used for a smoothing capacitor that includes a main body portion having a dielectric portion interposed between electrodes and suppresses fluctuations in DC voltage supplied to a switching element.

10: switching element 50: first smoothing capacitor (smoothing capacitor)
50a: Capacitor main body (main body)
51: Positive terminal 52: Negative terminal 53: Dielectric portion 54a: Positive side internal electrode 54b: Negative side internal electrode 70: Internal conductive layer A: Switching element arrangement region (arrangement region)
P1: positive electrode side connection electrode P2: negative electrode side connection electrode S1: element arrangement surface S4: first plane S5: second plane X: reference direction Z: direction orthogonal to the element arrangement surface

Claims (6)

A smoothing capacitor comprising a main body configured to have a dielectric portion interposed between electrodes, and suppressing fluctuations in DC voltage supplied to a switching element,
On the outer surface of the main body portion, the element arrangement surface formed integrally with the dielectric portion, and the element at the end of the element arrangement surface on one side in the reference direction set along the element arrangement surface A first plane intersecting the arrangement plane and a second plane intersecting the element arrangement plane at the end of the element arrangement plane on the other side in the reference direction, and a positive electrode terminal is formed on the first plane. And a negative electrode terminal is formed on the second plane,
The element arrangement surface includes a positive electrode side connection electrode electrically connected to the positive electrode terminal and a negative electrode side connection electrode electrically connected to the negative electrode terminal, and the positive electrode side connection electrode and the negative electrode side. The switching element can be arranged in a state of being electrically connected to at least one of the connection electrodes,
An internal conductive layer extending along the element arrangement surface is provided inside the main body,
The internal conductive layer is a smoothing capacitor formed such that a current flow direction in a direction perpendicular to the element arrangement surface has a component in a direction from the negative terminal toward the positive terminal in the reference direction.   The internal conductive layer has a portion overlapping at least one of the positive electrode side connection electrode and the negative electrode side connection electrode when viewed in a direction orthogonal to the element arrangement surface, and the arrangement of the switching elements on the element arrangement surface The smoothing capacitor according to claim 1, wherein the smoothing capacitor is formed so as to have a portion overlapping with the region. A positive electrode internal electrode extending from the positive electrode terminal toward the negative electrode terminal in the reference direction and a negative electrode internal electrode extending from the negative electrode terminal toward the positive electrode terminal in the reference direction are formed inside the main body. And
The positive electrode side internal electrode and the negative electrode side internal electrode are both formed on the side opposite to the element arrangement surface with respect to the internal conductive layer in a direction orthogonal to the element arrangement surface. The smoothing capacitor described.   The end regions on the negative terminal side in the reference direction of the internal conductive layer and the positive side internal electrode are connected to each other, and the end regions on the positive terminal side in the reference direction of the internal conductive layer The smoothing capacitor according to claim 3, wherein the positive electrode side connection electrode is connected to the positive electrode terminal via the internal conductive layer.   The end regions on the positive terminal side in the reference direction of the internal conductive layer and the negative side internal electrode are connected to each other, and the end region on the negative terminal side in the reference direction of the internal conductive layer The smoothing capacitor according to claim 3, wherein the negative electrode side connection electrode is connected to the negative electrode terminal via the internal conductive layer.   The smoothing capacitor according to claim 1, wherein the dielectric portion is made of a ceramic material.

Images