JP2016214012A - Power conversion device - Google Patents

Abstract

Provided is a power conversion device capable of shortening a wiring path between a switching element and a snubber circuit element and reducing a surge voltage. A power conversion device includes a wiring board having a pattern surface on which a wiring pattern is formed. On the wiring substrate 21, the first switching element 10U is joined. The first switching element 10U has one surface 31 having a drain electrode 12 and a source electrode 13 formed at a distance from each other, and the other surface 32 opposite thereto. The first switching element 10 </ b> U is bonded onto the wiring board 21 with one surface 31 facing the pattern surface 23 of the wiring board 21. A snubber circuit element 17 is interposed between the wiring board 21 and the first switching element 10U. The snubber circuit element 17 is electrically connected to the drain electrode 12 and the source electrode 13 between the wiring board 21 and the first switching element 10U. [Selection] Figure 5

Description

  The present invention relates to a power conversion device including a switching element and a snubber circuit element.

  Patent Document 1 discloses a snubber including a series circuit including two switching elements and a series circuit including a snubber capacitor (snubber circuit element) and a snubber resistor (snubber circuit element) connected in parallel to the series circuit of the two switching elements. A power module including a circuit is disclosed. The two switching elements are embedded in the multilayer substrate. One switching element is electrically connected to one conductor disposed on the multilayer substrate via a plurality of via conductors and a plurality of wiring layers formed in the multilayer substrate. The other switching element is electrically connected to other conductors disposed on the multilayer substrate via a plurality of via conductors and a plurality of wiring layers formed in the multilayer substrate. One conductor and the other conductor are connected to a snubber capacitor (snubber circuit element) disposed on the multilayer substrate via a snubber resistor (snubber circuit element) disposed in the multilayer substrate.

  Patent Document 2 discloses a metal substrate and a dielectric substrate that are arranged to face each other, a MOSFET (Metal Oxide Semiconductor Field Effect Transistor) bridge-connected to the metal substrate, and a dielectric so as to face the MOSFET above the MOSFET. An inverter device including a snubber capacitor (snubber circuit element) connected to a body substrate is disclosed. In this inverter device, the snubber capacitor (snubber circuit element) is connected to the MOSFET by a plate-like lead wiring extending from the metal substrate toward the dielectric substrate.

JP 2012-129309 A JP 2011-67045 A

  In a power converter provided with a switching element and a snubber circuit element, there is a problem of a surge voltage generated due to a parasitic inductance existing in a wiring path between the switching element and the snubber circuit element. For example, in the configurations disclosed in Patent Document 1 and Patent Document 2, since the wiring path between the switching element and the snubber circuit element is long, there is a problem that the parasitic inductance increases and the surge voltage increases.

Therefore, in a power converter provided with a switching element and a snubber circuit element, it is desired to reduce parasitic inductance existing between the switching element and the snubber circuit element in order to reduce a surge voltage.
Therefore, an object of the present invention is to provide a power conversion device that can shorten a wiring path between a switching element and a snubber circuit element and reduce a surge voltage.

  According to the first aspect of the present invention, a wiring board (21) having a pattern surface (23) on which a predetermined wiring pattern (22, 28, 29, 30) is formed and a first substrate formed at a distance from each other. In the state which has one surface (31) which has an electrode (12) and a 2nd electrode (13), and the other surface (32) on the other side, and made said one surface oppose the said pattern surface of the said wiring board A switching element (10U, 10V, 10W, 11U, 11V, 11W) bonded on the wiring board and a snubber circuit element (17) electrically connected between the first electrode and the second electrode And the snubber circuit element is disposed so as to be interposed between the wiring board and the switching element. In addition, although the alphanumeric characters in parentheses represent corresponding components in the embodiments described later, the scope of the claims is not intended to be limited to the embodiments. The same applies hereinafter.

  According to this configuration, the snubber circuit element is arranged so as to be interposed between the wiring board and the switching element. As a result, the distance between the switching element and the snubber circuit element is shortened, so that the wiring path between the switching element and the snubber circuit element can be shortened. As a result, since the parasitic inductance existing between the switching element and the snubber circuit element can be reduced, the surge voltage can be reduced.

According to a second aspect of the present invention, the one surface of the switching element has a control electrode (14) to which a signal for controlling a current between the first electrode and the second electrode is input. Item 4. The power conversion device according to Item 1.
According to a third aspect of the present invention, the first conductive member (41) is disposed so as to be interposed between the first electrode and the wiring pattern, and electrically connects the first electrode and the wiring pattern. And a second conductive member (42) disposed so as to be interposed between the second electrode and the wiring pattern and electrically connecting the second electrode and the wiring pattern. The power conversion device according to 1 or 2.

  When the snubber circuit element is interposed between the switching element and the wiring board, the switching element is arranged away from the pattern surface of the wiring board according to the thickness of the snubber circuit element. Therefore, in this configuration, the first conductive member and the second conductive member that electrically connect the first electrode and the second electrode of the switching element and the wiring pattern are interposed between the switching element and the wiring board. Thereby, even if the switching element is arranged apart from the wiring board, the switching element and the wiring pattern can be connected well.

In this configuration, since the first conductive member and the second conductive member are interposed between the wiring board and the switching element, the heat generated in the switching element is transmitted through the first conductive member and the second conductive member. Good transmission to the wiring board side. Thereby, heat dissipation can be improved and the temperature rise of a switching element can be suppressed.
The invention according to claim 4 is the power conversion device according to claim 3, wherein the first conductive member and the second conductive member are formed in a plate shape or a block shape.

  According to a fifth aspect of the present invention, the first conductive member is disposed on one end portion (17a) side of the snubber circuit element at a distance from the snubber circuit element, and the second conductive member is the snubber circuit. The snubber circuit element is disposed on the other end (17b) side of the snubber circuit element at a distance from the element, enters between the one end of the snubber circuit element and the first conductive member, and the first electrode and the snubber A first conductive bonding material (45) for electrically connecting one end of the circuit element and the first conductive member; and the other end of the snubber circuit element and the second conductive member; 5. The power conversion device according to claim 3, further comprising two electrodes, a second conductive bonding material (46) that electrically connects the other end of the snubber circuit element and the second conductive member. 6. .

  In this configuration, the first conductive bonding material and the second conductive bonding material are heated and melted in a state where the switching element is pressed against the wiring board. Part of the melted first conductive bonding material solidifies after entering between the one end portion of the snubber circuit element and the first conductive member by pressing of the switching element. Similarly, part of the melted second conductive bonding material solidifies after entering between the other end of the snubber circuit element and the second conductive member by pressing of the switching element.

  As a result, the first conductive bonding material and the second conductive bonding material can be prevented from solidifying at different thicknesses on the first conductive member and the second conductive member, so that the wiring can be performed in a state where the switching element is inclined. Bonding onto the substrate can be suppressed. That is, the switching element can be bonded onto the wiring board so that one surface of the switching element is parallel to the pattern surface of the wiring board. Moreover, since the adhesion of the switching element to the snubber circuit element, the first conductive member, and the second conductive member can be improved by the first conductive bonding material and the second conductive bonding material, the connection of the switching element to the wiring board Strength can be improved.

  According to a sixth aspect of the present invention, the first conductive member and the second conductive member have opposing surfaces (41a, 42a) facing each other in plan view, and the first conductive member and the second conductive member Concave portions (41b, 42b) recessed in a direction away from the other facing surface are formed on at least one facing surface of the conductive members, and a part of the snubber circuit element is disposed in the recessed portion. The power conversion device according to claim 5.

  According to this configuration, since a part of the snubber circuit element is arranged in the recess formed in at least one of the first conductive member and the second conductive member, the first conductive member and / or the second conductive member is disposed. The facing area between the member and the snubber circuit element can be increased. As a result, it is possible to increase the first conductive bonding material and / or the second conductive bonding material that enter between the recess formed in the first conductive member and / or the second conductive member and the snubber circuit element. The connection strength of the switching element can be further improved.

The invention according to claim 7 includes a plurality of snubber circuit elements, and the thickness of the plurality of snubber circuit elements is the same with respect to a direction perpendicular to the pattern surface of the wiring board, and It is a power converter device as described in any one of Claims 3-6 larger than each thickness of a said 1st conductive member and a said 2nd conductive member.
According to this configuration, the switching element is disposed on the plurality of snubber circuit elements having the same thickness. Thereby, it can suppress joining on a wiring board in the state which the switching element inclined. That is, the switching element can be bonded onto the wiring board so that one surface of the switching element is parallel to the pattern surface of the wiring board.

  The invention according to claim 8 is the first wiring (28) formed on the pattern surface of the wiring board so that the wiring pattern is electrically connected to the first electrode of the switching element. A second wiring (29) formed on the pattern surface of the wiring board at a distance from the first wiring so as to be electrically connected to the second electrode of the switching element, The first wiring and the second wiring have opposing surfaces (28a, 29a) that are opposed to each other in plan view, and at least one of the first wiring and the second wiring faces the other surface. 3. The power conversion according to claim 1, wherein a recessed portion (28 b, 29 b) that is recessed in a direction away from the facing surface is formed, and a part of the snubber circuit element is disposed in the recessed portion. Device.

  9. The power converter according to claim 8, wherein the snubber circuit element is inserted between one end (17a) of the snubber circuit element and the first wiring, and the one end of the snubber circuit element, the first electrode, and the first wiring are connected. The first conductive bonding material (45) to be electrically connected, the other end (17b) of the snubber circuit element, and the second wiring, the other end of the snubber circuit element, the second It is preferable to further include a second conductive bonding material (46) for electrically connecting the electrode and the second wiring.

The invention according to claim 9 includes a plurality of snubber circuit elements, and the thickness of the plurality of snubber circuit elements is the same with respect to a direction perpendicular to the pattern surface of the wiring board, and It is a power converter device of Claim 8 larger than each thickness of the said 1st wiring and the said 2nd wiring.
The invention according to claim 10 further includes a sealing resin (47) formed on the wiring board so as to collectively seal the switching element and the snubber circuit element. It is a power converter device of a statement. According to this configuration, the sealing resin can suppress the switching element and the snubber circuit element from being peeled off from the wiring board or displaced from the wiring board. That is, the connection strength of the switching element and the snubber circuit element to the wiring board can be improved by the sealing resin.

  Invention of Claim 11 is a power converter device as described in any one of Claims 1-10 which further contains the metal film (34) formed in the said other surface of the said switching element. According to this configuration, heat generated in the switching element can be dissipated to the outside through the metal film. Thereby, since heat dissipation can be improved, the temperature rise of a switching element can be suppressed.

  The invention according to claim 12 is the power conversion device according to claim 11, further comprising a radiator (36) connected to the metal film. According to this structure, since the heat dissipation can be further improved by the heat radiator connected to the metal film, the temperature rise of the switching element can be effectively suppressed.

FIG. 1 is a circuit diagram showing an electric circuit of a power converter according to an embodiment of the present invention. FIG. 2 is a perspective view showing the power converter. FIG. 3 is an exploded perspective view showing an element arrangement region in the U-phase arm formation region where the first switching element of the U-phase arm is arranged. FIG. 4 is a bottom view showing a main part of the first switching element. FIG. 5 is a cross-sectional view taken along the line V-V shown in FIG. FIG. 6 is a plan view showing conductive patterns arranged in the element arrangement region. FIG. 7 is a plan view showing the main part of the element arrangement region of the power conversion device according to the modification.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a circuit diagram showing an electric circuit of a power conversion device 1 according to an embodiment of the present invention.
Hereinafter, an example in which the power conversion device 1 is a three-phase inverter circuit that supplies power to the three-phase motor 2 will be described. The power converter 1 is connected to the DC power source 3 via the DC power source 3, the power switch 4, and the power switch 4, and is connected in parallel to the smoothing capacitor 5 that smoothes the DC voltage of the DC power source 3. Inverter unit 6.

The inverter unit 6 converts the DC voltage smoothed by the smoothing capacitor 5 into an AC voltage. The inverter unit 6 includes a U-phase arm 7, a V-phase arm 8, and a W-phase arm 9 corresponding to the U-phase, V-phase, and W-phase of the three-phase motor 2.
U-phase arm 7 is connected in parallel to smoothing capacitor 5 and includes a series circuit of first switching element 10U on the high side and second switching element 11U on the low side. V-phase arm 8 is connected in parallel to U-phase arm 7 and includes a series circuit of first switching element 10V on the high side and second switching element 11V on the low side. W-phase arm 9 is connected in parallel to V-phase arm 8 and includes a series circuit of first switching element 10W on the high side and second switching element 11W on the low side.

  FIG. 1 shows an example in which MOSFETs (Metal Oxide Semiconductor Field Effect Transistors) are employed as the switching elements 10U, 10V, 10W, 11U, 11V, and 11W. That is, each switching element 10U, 10V, 10W, 11U, 11V, 11W includes a drain electrode 12 (first electrode), a source electrode 13 (second electrode), and a gate electrode 14 (control electrode). The series circuit of each switching element 10U, 10V, 10W, 11U, 11V, 11W is connected to the source electrode 13 of the first switching element 10U, 10V, 10W and the drain electrode 12 of the second switching element 11U, 11V, 11W. Is formed. A signal for controlling the current between the drain electrode 12 and the source electrode 13 is input to each gate electrode 14 of each switching element 10U, 10V, 10W, 11U, 11V, 11W.

  A diode 15 is connected in reverse parallel between the drain electrode 12 and the source electrode 13 of each switching element 10U, 10V, 10W, 11U, 11V, 11W. A snubber circuit element 17 constituting a snubber circuit 16 is further connected in parallel between the drain electrode 12 and the source electrode 13 of each switching element 10U, 10V, 10W, 11U, 11V, 11W. That is, the snubber circuit 16 is connected to the diode 15 in parallel. In the present embodiment, an example in which the snubber circuit element 17 is composed of a capacitor is shown. Note that a parallel circuit composed of a plurality of (four in this embodiment) snubber circuit elements 17 is actually connected in parallel to each of the switching elements 10U, 10V, 10W, 11U, 11V, and 11W. FIG. 1 shows only one of the snubber circuit elements 17 for convenience of explanation.

  When the switching elements 10U, 10V, 10W, 11U, 11V, and 11W are turned off, a surge voltage is generated due to the parasitic inductance in the power converter 1, and ringing (noise) is generated. The surge voltage and ringing are suppressed by the snubber circuit element 17 connected in parallel to each switching element 10U, 10V, 10W, 11U, 11V, 11W.

  A connection portion between the first switching element 10 </ b> U and the second switching element 11 </ b> U of the U-phase arm 7 is connected to the U-phase of the three-phase motor 2 via the U-phase wiring 18. A connection portion between the first switching element 10 </ b> V and the second switching element 11 </ b> V of the V-phase arm 8 is connected to the V-phase of the three-phase motor 2 via the V-phase wiring 19. A connection portion between the first switching element 10 </ b> W and the second switching element 11 </ b> W of the W-phase arm 9 is connected to the W-phase of the three-phase motor 2 via the W-phase wiring 20.

FIG. 2 is a perspective view showing the power conversion device 1.
Referring to FIG. 2, power conversion device 1 includes a wiring board 21. The wiring board 21 is, for example, a multilayer wiring board. The multilayer wiring board may have a plurality of insulating layers, a plurality of wiring layers, and vias that electrically connect the wiring layers arranged above and below the insulating layer. A predetermined wiring pattern 22 (see FIG. 3) is formed on the uppermost layer of the multilayer wiring board. Hereinafter, the surface on which the wiring pattern 22 is formed is referred to as a pattern surface 23.

  The wiring board 21 is formed in a rectangular shape that is long in one direction when viewed from the normal direction of the pattern surface 23 (hereinafter simply referred to as “planar view”). On the pattern surface 23 of the wiring board 21, a U-phase arm formation region 24, a V-phase arm formation region 25, and a W-phase arm formation region 26 corresponding to the U-phase, V-phase, and W-phase of the three-phase motor 2 are set. Yes. The U-phase arm formation region 24, the V-phase arm formation region 25, and the W-phase arm formation region 26 have a rectangular shape in plan view, and are arranged in this order along the longitudinal direction of the wiring board 21.

  In U-phase arm formation region 24, first switching element 10U and second switching element 11U of U-phase arm 7 are arranged. In the V-phase arm formation region 25, the first switching element 10V and the second switching element 11V of the V-phase arm 8 are arranged. In the W-phase arm formation region 26, the first switching element 10W and the second switching element 11W of the W-phase arm 9 are arranged.

  That is, each of the arm formation regions 24, 25, and 26 has an element arrangement region in which the first switching elements 10U, 10V, and 10W are arranged and an element arrangement region in which the second switching elements 11U, 11V, and 11W are arranged. doing. The junction form of each switching element 10U, 10V, 10W, 11U, 11V, 11W in each element arrangement region is substantially the same. In the following, a description will be given by taking as an example a bonding form of the first switching element 10U.

FIG. 3 is an exploded perspective view showing an element arrangement region 27 in the U-phase arm formation region 24 in which the first switching element 10U of the U-phase arm 7 is arranged. FIG. 4 is a bottom view showing a main part of the first switching element 10U. FIG. 5 is a cross-sectional view taken along the line VV shown in FIG. In FIG. 4, the arrangement of the snubber circuit element 17 is also shown for the sake of clarity.
Referring to FIG. 3, the wiring pattern 22 includes a drain wiring 28 (first wiring), a source wiring 29 (second wiring), and a gate wiring 30 that are formed with a space therebetween. In the present embodiment, the drain wiring 28, the source wiring 29 and the gate wiring 30 are formed (embedded) in the wiring board 21 so as to be exposed from the pattern surface 23 of the wiring board 21. Each surface of the drain wiring 28, the source wiring 29 and the gate wiring 30 may be flush with the pattern surface 23.

  Referring to FIGS. 3 to 5, first switching element 10 </ b> U has a substantially rectangular parallelepiped shape, and has a drain electrode 12, a source electrode 13, and a gate electrode 14 (not shown) formed at intervals. It has a surface 31, the other surface 32 opposite to the surface 31, and four side surfaces 33 connecting the one surface 31 and the other surface 32. On one surface 31 of the first switching element 10U, the drain electrode 12, the source electrode 13, and the gate electrode 14 (not shown) are formed with a space therebetween.

  Referring to FIG. 4, drain electrode 12 includes a plurality of strip portions 12a extending in a stripe shape in a predetermined direction. Similarly, the source electrode 13 includes a plurality of strip portions 13a extending in a stripe shape in a predetermined direction. The strip portions 12a of the drain electrode 12 and the strip portions 13a of the source electrode 13 are alternately arranged so as to be parallel to each other. The drain electrode 12 and the source electrode 13 may be provided in a comb-teeth shape that meshes with each other on the one surface 31 of the first switching element 10U. Although not shown, the gate electrode 14 is formed on one side along one of the corners or the four side surfaces 33 on the one surface 31 of the first switching element 10U.

  The first switching element 10 </ b> U is bonded onto the wiring board 21 with one surface 31 facing the pattern surface 23 of the wiring board 21. With the first switching element 10U bonded to the wiring substrate 21, the drain electrode 12 is electrically connected to the drain wiring 28, the source electrode 13 is electrically connected to the source wiring 29, and the gate electrode 14 is connected to the gate wiring. 30 is electrically connected. On the other hand, no electrode is formed on the other surface 32 of the first switching element 10U. That is, the first switching element 10 </ b> U is a lateral switching element in which a current path is formed in the lateral direction parallel to the one surface 31 (and the other surface 32) between the drain electrode 12 and the source electrode 13.

  3 and 5, a metal film 34 is formed on the other surface 32 of the first switching element 10U so as to cover the entire region. The metal film 34 may be copper plating, for example. A heat radiator 36 is connected on the metal film 34 via a solder 35. The radiator 36 is a metal plate made of a metal material having a relatively high thermal conductivity such as aluminum, iron, or copper.

  3 to 5, a plurality (four in this embodiment) of snubber circuit elements 17 are provided on the wiring board 21 so as to be interposed between the wiring board 21 and the first switching element 10U. Is arranged. Assuming that the four snubber circuit elements 17 are divided into four regions that are similar to and congruent with the element arrangement region 27 in plan view, one snubber circuit element 17 is provided in each divided region. Arranged to be included. Each snubber circuit element 17 is, for example, a minute chip part made of ceramic having a substantially rectangular parallelepiped shape. Referring to FIG. 5, each snubber circuit element 17 is fixed on the wiring board 21 by, for example, an insulating adhesive 38. The thickness of the plurality of snubber circuit elements 17 is the same in the direction perpendicular to the pattern surface 23 of the wiring board 21.

  Each snubber circuit element 17 is arranged on the wiring board 21 so as to straddle the drain electrode 12 and the source electrode 13 adjacent to each other of the first switching element 10U. Each snubber circuit element 17 has one end 17a electrically connected to the drain electrode 12 of the first switching element 10U and the other end 17b electrically connected to the source electrode 13 of the first switching element 10U. Have. More specifically, each snubber circuit element 17 is electrically connected to the drain electrode 12 via the first terminal electrode 37a provided on the one end 17a side, and is provided on the second end 17b side. It is electrically connected to the source electrode 13 through the terminal electrode 37b. Thereby, a parallel circuit composed of four snubber circuit elements 17 is connected between the drain electrode 12 and the source electrode 13. One end portion 17 a (first terminal electrode 37 a) of each snubber circuit element 17 may be in contact with the drain electrode 12. Further, the other end 17 b (second terminal electrode 37 b) of each snubber circuit element 17 may be in contact with the source electrode 13.

With reference to FIGS. 3 and 5, a conductive pattern 40 is arranged around each snubber circuit element 17. Each conductive pattern 40 includes a first conductive member 41 and a second conductive member 42 that are plate-shaped or block-shaped (plate-shaped in this embodiment).
The first conductive member 41 of each conductive pattern 40 is disposed on the one end 17 a side of the snubber circuit element 17 at a distance from the snubber circuit element 17. The first conductive member 41 is formed in a rectangular shape extending along the drain wiring 28 (drain electrode 12) in plan view. The first conductive member 41 is disposed on the wiring board 21 so as to be interposed between the drain electrode 12 and the drain wiring 28 of the first switching element 10U. More specifically, the first conductive member 41 is bonded onto the drain wiring 28 by, for example, a conductive adhesive 43 such as a metal paste or solder. Each first conductive member 41 is electrically connected to the drain electrode 12 and the drain wiring 28.

  On the other hand, the second conductive member 42 of each conductive pattern 40 is arranged on the other end 17 b side of the snubber circuit element 17 with a space from the snubber circuit element 17. The second conductive member 42 is formed in a rectangular shape extending along the source wiring 29 (source electrode 13) in plan view. The second conductive member 42 is disposed on the wiring substrate 21 so as to be interposed between the source electrode 13 and the source wiring 29 of the first switching element 10U. More specifically, the second conductive member 42 is bonded onto the source wiring 29 by, for example, a conductive adhesive 43 such as a metal paste or solder. Each second conductive member 42 is electrically connected to the source electrode 13 and the source wiring 29.

Regarding the direction perpendicular to the pattern surface 23 of the wiring board 21, the thicknesses of the first conductive member 41 and the second conductive member 42 are both the same and smaller than the thickness of the snubber circuit element 17. That is, the thickness of the plurality of snubber circuit elements 17 is greater than the thickness of each of the first conductive member 41 and the second conductive member 42.
Hereinafter, a specific configuration of the conductive pattern 40 will be described with reference to FIG. FIG. 6 is a plan view showing the conductive pattern 40 arranged in the element arrangement region 27.

  The first conductive member 41 and the second conductive member 42 are arranged to face each other with the snubber circuit element 17 interposed therebetween. The first conductive member 41 has a facing surface 41 a that faces the second conductive member 42, and the second conductive member 42 has a facing surface 42 a that faces the first conductive member 41. A first recess 41 b that is recessed in a direction away from the facing surface 42 a of the second conductive member 42 is formed on the facing surface 41 a of the first conductive member 41. The first recess 41 b is formed in the middle portion in the longitudinal direction of the first conductive member 41. Similarly, a second recess 42 b that is recessed in a direction away from the facing surface 41 a of the first conductive member 41 is formed on the facing surface 42 a of the second conductive member 42. The second recess 42 b is formed in the middle in the longitudinal direction of the second conductive member 42.

  The first concave portion 41b and the second concave portion 42b are formed at positions facing each other, and a snubber circuit element accommodating region 44 having a substantially rectangular shape in plan view is formed by the first concave portion 41b, the second concave portion 42b, and the region therebetween. (Refer to the one-dot chain line in FIG. 6). The snubber circuit element 17 is disposed in the snubber circuit element accommodation region 44. One end portion 17 a of the snubber circuit element 17 is disposed in the first recess 41 b at a distance from the first conductive member 41. That is, the first recess 41 b faces the three side surfaces of the snubber circuit element 17 on the one end 17 a side of the snubber circuit element 17. On the other hand, the other end 17 b of the snubber circuit element 17 is disposed in the second recess 42 b with a space from the second conductive member 42. That is, the second recess 42 b faces the three side surfaces of the snubber circuit element 17 on the other end 17 b side of the snubber circuit element 17.

  Referring again to FIG. 5, the drain electrode 12, the one end portion 17 a of the snubber circuit element 17 and the first conductive member 41 are electrically connected by a first conductive bonding material 45. On the other hand, the source electrode 13, the other end 17 b of the snubber circuit element 17 and the second conductive member 42 are electrically connected by a second conductive bonding material 46. The first conductive bonding material 45 and the second conductive bonding material 46 may be, for example, a resin containing a conductive filler (for example, an epoxy resin), solder, or the like.

  The first conductive bonding material 45 is provided so as to enter between the one end portion 17 a of the snubber circuit element 17 and the first conductive member 41. Further, the first conductive bonding material 45 is provided so as to be interposed between the drain electrode 12 and the first conductive member 41. Although not shown, the first conductive bonding material 45 may be interposed between the one end portion 17 a (first terminal electrode 37 a) of the snubber circuit element 17 and the drain electrode 12.

  On the other hand, the second conductive bonding material 46 is provided so as to enter between the other end portion 17 b of the snubber circuit element 17 and the second conductive member 42. Further, the second conductive bonding material 46 is provided so as to be interposed between the source electrode 13 and the second conductive member 42. Although not shown, the second conductive bonding material 46 may be interposed between the other end 17 b (second terminal electrode 37 b) of the snubber circuit element 17 and the source electrode 13.

  A sealing resin 47 is formed on the wiring substrate 21 so as to collectively seal the first switching element 10U, the snubber circuit element 17 and the conductive pattern 40 (the first conductive member 41 and the second conductive member 42). ing. The sealing resin 47 is, for example, an epoxy resin. The sealing resin 47 is filled between the first switching element 10U and the wiring substrate 21 and is formed so as to cover the entire side surface 33 of the first switching element 10U. The radiator 36 is exposed from the sealing resin 47 in a state where the first switching element 10 </ b> U is sealed with the sealing resin 47. That is, the sealing resin 47 is filled between the wiring board 21 and the radiator 36.

  As described above, in the present embodiment, the snubber circuit element 17 is disposed so as to be interposed between the wiring board 21 and the first switching element 10U. The snubber circuit element 17 includes one end portion 17a electrically connected to the drain electrode 12 of the first switching element 10U and the source electrode 13 of the first switching element 10U between the wiring board 21 and the first switching element 10U. The other end portion 17b is electrically connected to the other end portion 17b.

According to this configuration, since the distance between the first switching element 10U and the snubber circuit element 17 is shortened, the wiring path between the first switching element 10U and the snubber circuit element 17 can be shortened. Thereby, since the parasitic inductance which exists between the 1st switching element 10U and the snubber circuit element 17 can be reduced, a surge voltage can be reduced.
In the present embodiment, the first conductive member 41 that electrically connects the drain electrode 12 and the source electrode 13 of the first switching element 10U and the wiring pattern 22 between the wiring substrate 21 and the first switching element 10U, and A second conductive member 42 is interposed. Thereby, even if the 1st switching element 10U is spaced apart and arrange | positioned from the wiring board 21, the 1st switching element 10U and the wiring pattern 22 can be connected favorably.

  In the present embodiment, since the first conductive member 41 and the second conductive member 42 are interposed between the wiring board 21 and the first switching element 10U, the heat generated in the first switching element 10U is the first. It can be satisfactorily transmitted to the wiring board 21 via the conductive member 41 and the second conductive member 42. Thereby, heat dissipation can be improved and the temperature rise of the 1st switching element 10U can be suppressed.

  In the present embodiment, the first conductive bonding material 45 entering between the one end portion 17 a of the snubber circuit element 17 and the first conductive member 41, the other end portion 17 b of the snubber circuit element 17, and the second conductive member 42. And a second conductive bonding material 46 entering between the two. The first conductive bonding material 45 and the second conductive bonding material 46 are heated and melted in a state where the first switching element 10U is pressed against the wiring board 21. A part of the melted first conductive bonding material 45 enters between the one end portion 17a of the snubber circuit element 17 and the first conductive member 41 by the pressing of the first switching element 10U, and then solidifies. Similarly, a part of the melted second conductive bonding material 46 enters between the other end portion 17b of the snubber circuit element 17 and the second conductive member 42 by the pressing of the first switching element 10U, and then solidifies. .

  Thereby, it is possible to suppress the first conductive bonding material 45 and the second conductive bonding material 46 from solidifying at different thicknesses on the first conductive member 41 and the second conductive member 42. Moreover, according to the present embodiment, the first switching element 10U is disposed on the plurality of snubber circuit elements 17 having the same thickness. Thereby, it can suppress joining on the wiring board 21 in the state in which the 1st switching element 10U inclined. That is, the first switching element 10U can be bonded onto the wiring board 21 so that the one surface 31 (and the other surface 32) of the first switching element 10U is parallel to the pattern surface 23 of the wiring board 21.

  Further, the first conductive bonding material 45 and the second conductive bonding material 46 can improve the adhesion of the first switching element 10U to the snubber circuit element 17, the first conductive member 41, and the second conductive member 42. The connection strength of the first switching element 10U to the wiring board 21 can be improved. In particular, according to the present embodiment, the one end 17a and the other end 17b of the snubber circuit element 17 are placed in the first recess 41b and the second recess 42b formed in the first conductive member 41 and the second conductive member 42, respectively. Is arranged. As a result, the opposing area between the first conductive member 41 and the second conductive member 42 and the snubber circuit element 17 increases, so that the first conductive material that enters between the first concave portion 41b and the second concave portion 42b and the snubber circuit element 17 is obtained. The conductive bonding material 45 and the second conductive bonding material 46 can be increased. As a result, the connection strength of the first switching element 10U can be further improved.

  In the present embodiment, the sealing resin 47 that collectively seals the first switching element 10U, the snubber circuit element 17 and the conductive pattern 40 is formed on the pattern surface 23 of the wiring board 21. According to this configuration, the sealing resin 47 effectively prevents the first switching element 10U, the snubber circuit element 17 and the conductive pattern 40 from being separated from the wiring board 21 or displaced from the wiring board 21. Can be suppressed. That is, the sealing resin 47 can further improve the connection strength of the first switching element 10U, the snubber circuit element 17 and the conductive pattern 40 to the wiring board 21.

  In the present embodiment, a metal film 34 is formed on the other surface 32 of the first switching element 10 </ b> U, and a radiator 36 is connected on the metal film 34. Thereby, the heat generated in the first switching element 10 </ b> U can be dissipated to the outside by the metal film 34 and the radiator 36. As a result, since heat dissipation can be improved, the temperature rise of the first switching element 10U can be effectively suppressed.

  Here, a case where the first switching element 10U is joined in a state of being inclined with respect to the pattern surface 23 of the wiring board 21 will be considered. In this case, there is a possibility that a part of the first switching element 10 </ b> U may be peeled off from the wiring board 21 due to pressing when connecting the radiator 36. On the other hand, according to the present embodiment, as described above, the one surface 31 (and the other surface 32) of the first switching element 10U is parallel to the pattern surface 23 of the wiring board 21. The first switching element 10U can be connected to the wiring board 21. Therefore, the radiator 36 can be connected to the first switching element 10 </ b> U while suppressing the first switching element 10 </ b> U from being separated from the wiring substrate 21.

As mentioned above, although embodiment of this invention was described, this invention can also be implemented with another form.
For example, in the above-described embodiment, the example in which the MOSFET is employed as an example of each switching element 10U, 10V, 10W, 11U, 11V, 11W has been described. However, each of the switching elements 10U, 10V, 10W, 11U, 11V, and 11W may be a bipolar transistor or an IGBT (Insulated Gate Bipolar Transistor) instead of the MOSFET.

  When each of the switching elements 10U, 10V, 10W, 11U, 11V, and 11W is composed of a bipolar transistor, each of the switching elements 10U, 10V, 10W, 11U, 11V, and 11W includes a collector electrode (first electrode) and an emitter electrode (second electrode). Electrode) and base electrode (control electrode). In this case, referring to FIG. 1, each series circuit of U-phase arm 7, V-phase arm 8 and W-phase arm 9 includes an emitter electrode of first switching elements 10U, 10V and 10W, and second switching element 11U, It is formed by connecting 11V and 11W collector electrodes.

  On the other hand, when each switching element 10U, 10V, 10W, 11U, 11V, 11W is made of IGBT, each switching element 10U, 10V, 10W, 11U, 11V, 11W includes a collector electrode (first electrode) and an emitter electrode (first electrode). 2 electrodes) and a gate electrode (control electrode). In this case, referring to FIG. 1, each series circuit of U-phase arm 7, V-phase arm 8 and W-phase arm 9 includes an emitter electrode of first switching elements 10U, 10V and 10W, and second switching element 11U, It is formed by connecting 11V and 11W collector electrodes.

  In the above-described embodiment, the example in which the snubber circuit 16 includes a plurality of snubber circuit elements 17 formed of capacitors has been described. However, the snubber circuit 16 may include one or more snubber circuit elements 17 made of resistors. The snubber circuit 16 may include one or a plurality of series circuits and / or parallel circuits configured by a snubber circuit element 17 made of a capacitor and a snubber circuit element 17 made of a resistor.

In the above-described embodiment, the example in which one conductive pattern 40 including the first conductive member 41 and the second conductive member 42 is arranged around one snubber circuit element 17 has been described. However, a single conductive pattern 40 may be disposed across the periphery of the plurality of snubber circuit elements 17.
In the above-described embodiment, the example in which the drain wiring 28, the source wiring 29, and the gate wiring 30 are formed in the wiring board 21 to be exposed from the pattern surface 23 of the wiring board 21 has been described. In this configuration, the snubber circuit element 17 may be arranged on the wiring board 21 so that the snubber circuit element 17 is directly electrically connected to the drain wiring 28 and the source wiring 29 without providing the conductive pattern 40. Good. In other words, the snubber circuit element 17 may have one end 17 a that is directly electrically connected to the drain wiring 28 and the other end 17 b that is directly electrically connected to the source wiring 29.

  In the above-described embodiment, the drain wiring 28, the source wiring 29, and the gate wiring 30 have a predetermined thickness (for example, a thickness that is about 0.1 mm to 0.2 mm smaller than the thickness of the snubber circuit element 17). It may be formed on the pattern surface 23 of the wiring board 21. In this case, the configuration shown in FIG. 7 may be adopted. FIG. 7 is a plan view showing a main part of the element arrangement region 27 of the power conversion device 51 according to the modification.

  Referring to FIG. 7, power converter 51 does not include conductive pattern 40 (first conductive member 41 and second conductive member 42) unlike the configuration of power converter 1 described above. In the power conversion device 51, the drain wiring 28 and the source wiring 29 include stripe portions formed so as to face each other with the snubber circuit element 17 interposed therebetween. The drain wiring 28 has a facing surface 28 a that faces the source wiring 29, and the source wiring 29 has a facing surface 29 a that faces the drain wiring 28.

  A first recess 28 b that is recessed in a direction away from the facing surface 29 a of the source wiring 29 is formed on the facing surface 28 a of the drain wiring 28. Similarly, a second recess 29 b that is recessed in a direction away from the facing surface 28 a of the drain wiring 28 is formed on the facing surface 29 a of the source wiring 29. The first concave portion 28b and the second concave portion 29b are formed at positions facing each other, and a snubber circuit element accommodating region 52 having a substantially rectangular shape in plan view is formed by the first concave portion 28b, the second concave portion 29b, and the region therebetween. (Refer to the one-dot chain line in FIG. 7).

  The snubber circuit element 17 is disposed in the snubber circuit element accommodation region 52. One end portion 17 a of the snubber circuit element 17 is disposed in the first recess 28 b at a distance from the drain wiring 28. That is, the first recess 28 b faces the three side surfaces of the snubber circuit element 17 on the one end 17 a side of the snubber circuit element 17. On the other hand, the other end 17 b of the snubber circuit element 17 is disposed in the second recess 29 b with a space from the source wiring 29. That is, the second recess 29 b faces the three side surfaces of the snubber circuit element 17 on the other end 17 b side of the snubber circuit element 17.

In the power conversion device 51, the one end portion 17a of the snubber circuit element 17, the drain electrode 12, and the drain wiring 28 are electrically connected by a first conductive bonding material 45 (see FIG. 5). On the other hand, the other end 17b of the snubber circuit element 17, the source electrode 13, and the source wiring 29 are electrically connected by a second conductive bonding material 46 (see FIG. 5).
The first conductive bonding material 45 is provided so as to enter between the one end portion 17 a of the snubber circuit element 17 and the drain wiring 28. Further, the first conductive bonding material 45 is provided so as to be interposed between the drain electrode 12 and the drain wiring 28. The first conductive bonding material 45 may be interposed between the one end portion 17 a (first terminal electrode 37 a) of the snubber circuit element 17 and the drain electrode 12.

  On the other hand, the second conductive bonding material 46 is provided so as to enter between the other end portion 17 b of the snubber circuit element 17 and the second conductive member 42. Further, the second conductive bonding material 46 is provided so as to be interposed between the source electrode 13 and the second conductive member 42. The second conductive bonding material 46 may be interposed between the other end portion 17 b (second terminal electrode 37 b) of the snubber circuit element 17 and the source electrode 13.

  As described above, in this example, the snubber circuit element accommodation region 52 (the first recess 28b and the second recess 29b) formed using the drain wiring 28 and the source wiring 29 provided on the pattern surface 23 of the wiring board 21 is used. A snubber circuit element 17 is arranged. According to this configuration, it is possible to achieve the same effect as the effect described in the above embodiment while realizing a relatively simple configuration.

Further, in the above-described embodiment, at least one facing surface of the drain electrode 12 (band-like portion 12a; see FIG. 4) and the source electrode (band-like portion 13a, see FIG. 4) is separated from the other facing surface. A recessed portion that is recessed may be formed, and a part of the snubber circuit element 17 may be disposed in the recessed portion.
In addition, various design changes can be made within the scope of matters described in the claims.

  DESCRIPTION OF SYMBOLS 1 ... Power converter device, 10U, 10V, 10W ... 1st switching element, 11U, 11V, 11W ... 2nd switching element, 12 ... Drain electrode (1st electrode), 13 ... Source electrode (2nd electrode), 14 ... Gate electrode (control electrode), 17 ... snubber circuit element, 17a ... one end of snubber circuit element, 17b ... other end of snubber circuit element, 21 ... wiring board, 22 ... wiring pattern, 23 ... pattern surface of wiring board, 28 ... Drain wiring (first wiring), 28a ... Drain wiring facing surface, 28b ... Drain wiring first recess (concave), 29 ... Source wiring (second wiring), 28a ... Source wiring facing surface, 28b ... Second concave portion (concave portion) of source wiring, 31... One surface of first switching element, 32... Other surface of first switching element, 34... Metal film, 36. Member 41a ... opposing surface of the first conductive member, 41b ... first recess (concave portion) of the first conductive member, 42 ... second conductive member, 42a ... opposing surface of the second conductive member, 42b ... of the second conductive member 2nd recessed part (recessed part), 45 ... 1st electroconductive joining material, 46 ... 2nd electroconductive joining material, 47 ... Sealing resin, 51 ... Power converter device

Claims (12)

A wiring board having a pattern surface on which a predetermined wiring pattern is formed;
The wiring having one surface having a first electrode and a second electrode formed at a distance from each other and the other surface opposite to the first electrode, and the one surface facing the pattern surface of the wiring board A switching element bonded on the substrate;
A snubber circuit element electrically connected between the first electrode and the second electrode;
The power converter device, wherein the snubber circuit element is disposed so as to be interposed between the wiring board and the switching element.   2. The power conversion device according to claim 1, wherein the one surface of the switching element includes a control electrode to which a signal for controlling a current between the first electrode and the second electrode is input. A first conductive member disposed so as to be interposed between the first electrode and the wiring pattern, and electrically connecting the first electrode and the wiring pattern;
3. The apparatus according to claim 1, further comprising a second conductive member that is disposed so as to be interposed between the second electrode and the wiring pattern and electrically connects the second electrode and the wiring pattern. Power converter.   The power conversion device according to claim 3, wherein the first conductive member and the second conductive member are formed in a plate shape or a block shape. The first conductive member is disposed on one end side of the snubber circuit element with a space from the snubber circuit element, and the second conductive member is spaced apart from the snubber circuit element. Arranged on the end side,
A first conductive bonding material that enters between the one end portion of the snubber circuit element and the first conductive member, and electrically connects the first electrode, the one end portion of the snubber circuit element, and the first conductive member; ,
A second conductive junction that enters between the other end of the snubber circuit element and the second conductive member and electrically connects the second electrode, the other end of the snubber circuit element, and the second conductive member. The power converter according to claim 3 or 4 further including material. The first conductive member and the second conductive member have opposing surfaces that are opposed to each other in plan view, and at least one opposing surface of the first conductive member and the second conductive member A recess that is recessed in a direction away from the facing surface is formed,
The power converter according to claim 5, wherein a part of the snubber circuit element is disposed in the recess. Including a plurality of the snubber circuit elements;
The thickness of the plurality of snubber circuit elements is the same with respect to the direction perpendicular to the pattern surface of the wiring board, and is larger than the thicknesses of the first conductive member and the second conductive member, The power converter device as described in any one of Claims 3-6. The wiring pattern is electrically connected to the first wiring formed on the pattern surface of the wiring board so as to be electrically connected to the first electrode of the switching element, and to the second electrode of the switching element. A second wiring formed on the pattern surface of the wiring board at a distance from the first wiring so as to be connected to the first wiring,
The first wiring and the second wiring have opposing surfaces facing each other in plan view, and are separated from at least one opposing surface of the first wiring and the second wiring from the other opposing surface. A concave portion is formed in the direction of
The power converter according to claim 1 or 2 with which a part of said snubber circuit element is arranged in said crevice. Including a plurality of the snubber circuit elements;
The thickness of the plurality of snubber circuit elements is the same in a direction perpendicular to the pattern surface of the wiring board, and is larger than each thickness of the first wiring and the second wiring. 8. The power conversion device according to 8.   The power converter according to any one of claims 1 to 9, further comprising a sealing resin formed on the wiring board so as to collectively seal the switching element and the snubber circuit element.   The power converter according to any one of claims 1 to 10, further comprising a metal film formed on the other surface of the switching element.   The power conversion device according to claim 11, further comprising a radiator connected to the metal film.

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