JP2015015787A - Power conversion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power conversion device that can easily manufacture a positive electrode bus bar and a negative electrode bus bar having narrow pitches of a terminal connection portion, and can prevent a large surge voltage from being applied to a semiconductor element through which a large current passes.SOLUTION: A power conversion device 1 includes: a laminate 10 in which a plurality of semiconductor modules 2 are laminated; a positive electrode bus bar 3; and a negative electrode bus bar 4. The positive electrode bus bar 3 and the negative electrode bus bar 4 are formed of a plurality of bus bar pieces 30 and 40 overlapping each other. The respective bus bar pieces 30 and 40 have substrate portions 31 and 41. The substrate portions 31 and 41 are large-current substrate portions 31a and 41a connected to a large-current semiconductor module 2a, and small-current substrate portions 31b and 41b connected to a small-current semiconductor module 2b. A distance D1 between the large-current substrate portions 31a and 41a in a Z direction is narrower than a distance D2 between the small-current substrate portions 31b and 41b.

Description

  The present invention relates to a semiconductor module incorporating a semiconductor element, and a power conversion device including a positive bus bar and a negative bus bar connected to the semiconductor module.

  For example, as a power conversion device that performs power conversion between DC power and AC power, a device in which a semiconductor module incorporating a semiconductor element and a cooling pipe that cools the semiconductor module are stacked is known (Patent Documents below) 1).

  The semiconductor module includes a main body portion incorporating a semiconductor element, and a positive terminal, a negative terminal, and an AC terminal protruding from the main body portion. A positive electrode bus bar is connected to the positive electrode terminal, and a negative electrode bus bar is connected to the negative electrode terminal. A DC voltage is applied to the positive terminal and the negative terminal through these bus bars. By switching the semiconductor element, a DC voltage applied between the positive terminal and the negative terminal is converted into an AC voltage and output from the AC terminal.

  Each of the positive electrode bus bar and the negative electrode bus bar has a plate-like substrate portion and a plurality of terminal connection portions extending from the substrate portion. This terminal connection portion is connected to the positive terminal or the negative terminal.

JP 2010-115061 A

  However, the power conversion device has a problem that a large surge voltage is easily applied to a specific semiconductor element with the switching operation. In other words, there are semiconductor devices in which a large current flows and a semiconductor device in which a small current flows due to different loads to be connected. A semiconductor element in which a large current I flows is likely to have a large amount of time change dI / dt of the current I when the current is interrupted, compared to a semiconductor element in which a small current flows. The surge voltage V applied to the semiconductor element is the product (LdI / dt) of the time variation dI / dt and the inductance L attached to the circuit. Therefore, a large surge voltage V (= LdI / dt) is likely to be applied to a semiconductor element in which a large current flows and the time change amount dI / dt of the current I has a large value.

  On the other hand, in recent years, it has been desired to reduce the thickness of a semiconductor module or a cooling pipe in order to reduce the size of a power converter. However, when the thickness is reduced, the distance between the semiconductor modules in the stacking direction is narrowed, and thus the pitch of the terminal connection portions needs to be narrowed. Therefore, the problem that it becomes difficult to manufacture a positive electrode bus bar and a negative electrode bus bar arises.

  The present invention has been made in view of such a background, and can easily manufacture a positive electrode bus bar and a negative electrode bus bar having a narrow pitch of terminal connection portions, and a large surge voltage is applied to a semiconductor element through which a large current flows. An object of the present invention is to provide a power conversion device that can suppress the above.

One aspect of the present invention is a stacked body in which a plurality of semiconductor modules in which power terminals protrude from a body portion incorporating a semiconductor element are stacked in a state where each of the power terminals faces in the same direction;
Each of the semiconductor modules is electrically connected, and includes a positive electrode bus bar and a negative electrode bus bar to which a DC voltage is applied between each other,
The positive electrode bus bar and the negative electrode bus bar are composed of a plurality of bus bar pieces superposed on each other, and each of the bus bar pieces has a substrate portion arranged so that a main surface thereof is orthogonal to a protruding direction of the power terminal, A plurality of terminal connecting portions extending from the substrate portion in the width direction perpendicular to both the stacking direction of the laminate and the protruding direction and connected to the power terminals;
The positive electrode bus bar and the negative electrode bus bar are configured by superimposing the respective substrate portions so that the terminal connection portions formed on the same bus bar piece are not adjacent to each other in the stacking direction. ,
The semiconductor module includes a large current semiconductor module in which a current flowing through the semiconductor element is relatively large and a small current semiconductor module in which a current flowing through the semiconductor element is less than that of the large current semiconductor module.
The substrate portion of the plurality of bus bar pieces constituting the positive electrode bus bar and the negative electrode bus bar respectively includes a large current substrate portion in which the terminal connection portion is connected to the large current semiconductor module, and a small current semiconductor module. There is a small current board part connected,
An interval in the protruding direction between the large current substrate portion included in the positive electrode bus bar and the large current substrate portion included in the negative electrode bus bar is included in the small current substrate portion included in the positive electrode bus bar and the negative electrode bus bar. The power converter is characterized by being narrower than the distance between the small current substrate portion and the protruding direction.

Each of the positive electrode bus bar and the negative electrode bus bar of the power conversion device includes a plurality of bus bar pieces. Each bus bar piece has the substrate portion and the terminal connection portion. The positive electrode bus bar and the negative electrode bus bar are configured by overlapping the substrate parts so that the terminal connection parts formed on the same bus bar piece are not adjacent to each other in the stacking direction.
If it does in this way, the positive electrode bus bar and negative electrode bus bar with which the pitch of a terminal-connection part is narrow can be manufactured easily. That is, it is difficult to manufacture a positive electrode bus bar or a negative electrode bus bar with a narrow pitch of terminal connection parts by pressing one metal plate or the like, but a bus bar piece with a wide pitch of terminal connection parts is easy to manufacture. . According to the above power converter, a plurality of bus bar pieces with a wide terminal connection portion pitch can be manufactured, and the bus bar pieces can be combined to reduce the terminal connection portion pitch in the combined state. Therefore, it is possible to easily manufacture a positive electrode bus bar and a negative electrode bus bar having a narrow pitch of terminal connection portions.
Moreover, if it is set as the said structure, the width | variety (length in the said lamination direction) of each terminal connection part can be lengthened. Therefore, the self-inductance of the positive electrode bus bar and the negative electrode bus bar can be reduced.

In addition, the power conversion device can reduce a surge voltage applied to a semiconductor element through which a large current flows. In other words, in the above configuration, since the interval between the large current substrate portion included in the positive electrode bus bar and the large current substrate portion included in the negative electrode bus bar is relatively narrow, the parasitic current between the large current substrate portions is limited. The inductance L can be reduced. A semiconductor element electrically connected to a large current substrate portion, that is, a semiconductor element through which a large current flows, has a large time change amount dI / dt of the current I at the time of current interruption, but reduces the parasitic inductance L attached to the large current substrate portion. Therefore, the surge voltage V (= LdI / dt) does not have to be particularly large.
Moreover, since the space | interval of the said small electric current board part contained in a positive electrode bus bar and the small electric current board part contained in a negative electrode bus bar is relatively wide, the parasitic inductance L attached between these small electric current board parts is large. Prone. However, a semiconductor element electrically connected to the small current substrate portion, that is, a semiconductor element with a small flowing current has a small amount of time change dI / dt of the current I at the time of current interruption, and therefore, a surge voltage V (= LdI) applied to the semiconductor element. / Dt) is not particularly large.

  As described above, according to the present invention, it is possible to easily manufacture a positive electrode bus bar and a negative electrode bus bar with a narrow pitch of terminal connection portions, and to suppress the application of a large surge voltage to a semiconductor element through which a large current flows. A conversion device can be provided.

It is sectional drawing of the power converter device in Example 1, Comprising: II sectional drawing of FIG. The principal part enlarged view of FIG. FIG. 3 is a view taken in the direction of arrow III in FIG. 1. IV-IV sectional drawing of FIG. The principal part enlarged view of FIG. The top view before the bending of one bus-bar piece which comprises a positive electrode bus bar in Example 1. FIG. The top view after bending of the bus-bar piece shown in FIG. The top view before bending of the other bus-bar piece which comprises a positive electrode bus bar in Example 1. FIG. The top view after bending of the bus-bar piece shown in FIG. The top view of the positive electrode bus bar in the state which piled up two bus-bar pieces in Example 1. FIG. The perspective view of the positive electrode bus bar shown in FIG. The top view before the bending of one bus-bar piece which comprises the negative electrode bus bar in Example 1. FIG. The top view after bending of the bus-bar piece shown in FIG. The top view before the bending of the other bus-bar piece which comprises a negative electrode bus bar in Example 1. FIG. The top view after bending of the bus-bar piece shown in FIG. The top view of the negative electrode bus bar in the state which piled up two bus-bar pieces in Example 1. FIG. The perspective view of the negative electrode bus bar shown in FIG. The top view in the state which excluded the positive electrode bus bar and the negative electrode bus bar from the power converter device shown in FIG. The circuit diagram of the power converter device in Example 1. FIG. Sectional drawing of the power converter device in Example 2. FIG. The top view of the positive electrode bus bar in Example 2. FIG. The principal part expanded sectional view of the power converter device in Example 3. FIG. The principal part expanded sectional view of the power converter device in Example 4. FIG.

  The power conversion device can be a vehicle-mounted power conversion device to be mounted on, for example, a hybrid vehicle or an electric vehicle.

Example 1
The Example which concerns on the said power converter device is described using FIGS. As shown in FIGS. 3 and 4, the power conversion device 1 of this example includes a stacked body 10 in which a plurality of semiconductor modules 2 are stacked, a positive bus bar 3, and a negative bus bar 4. The semiconductor module 2 has a main body portion 20 in which a semiconductor element 29 (see FIG. 19) is built. A power terminal 21 protrudes from the main body 20. The semiconductor module 2 is stacked with the power terminals 21 facing in the same direction. The positive electrode bus bar 3 and the negative electrode bus bar 4 are electrically connected to the semiconductor module 2, respectively.

As shown in FIGS. 1 and 3, the positive electrode bus bar 3 includes a plurality of bus bar pieces 30 (30a, 30b) overlapped with each other. Each bus bar piece 30a, 30b has a substrate part 31 (31a, 31b) and a terminal connection part 32. The substrate part 31 is arranged such that its main surface 310 is orthogonal to the protruding direction (Z direction) of the power terminal 21. The terminal connection portion 32 extends from the substrate portion 31 in the width direction (Y direction) perpendicular to both the stacking direction (X direction) and the Z direction of the stacked body 10 and is connected to the power terminal 21.
Similarly, the negative electrode bus bar 4 also includes a plurality of bus bar pieces 40 (40a, 40b). Each bus bar piece 40 a, 40 b has a substrate part 41 (41 a, 41 b) and a terminal connection part 42. The substrate part 41 is arranged such that its main surface 410 is orthogonal to the Z direction. The terminal connection portion 42 extends in the Y direction from the substrate portion 41 and is connected to the power terminal 21.

  As shown in FIG. 3, the positive electrode bus bar 3 is configured by superimposing the respective substrate portions 31 a and 31 b so that the terminal connection portions 32 formed on the same bus bar piece 30 are not adjacent to each other in the X direction. ing. The same applies to the negative electrode bus bar 4.

The semiconductor module 2 includes a large current semiconductor module 2a in which a current flowing in the semiconductor element 29 is relatively large and a small current semiconductor module 2b in which a current flowing in the semiconductor element 29 is smaller than that in the large current semiconductor module 2a.
As shown in FIGS. 3 and 4, a large current substrate in which terminal connection portions 32 and 42 are connected to the large current semiconductor module 2 a is connected to the plurality of substrate portions 31 and 41 that respectively constitute the positive electrode bus bar 3 and the negative electrode bus bar 4. There are portions 31a and 41a and small current substrate portions 31b and 41b connected to the small current semiconductor module 2b.

  As shown in FIGS. 2 and 5, the distance D <b> 1 in the Z direction between the large current substrate portion 31 a included in the positive electrode bus bar 3 and the large current substrate portion 41 a included in the negative electrode bus bar 4 is a small current included in the positive electrode bus bar 3. It is narrower than the distance D2 in the Z direction between the substrate portion 31b and the small current substrate portion 41b included in the negative electrode bus bar 4.

  The power conversion device 1 of this example is a vehicle-mounted power conversion device to be mounted on a vehicle such as an electric vehicle or a hybrid vehicle.

  As shown in FIG. 19, two three-phase AC motors 81 and 82 are connected to the power conversion device 1 of this example. Then, by switching the semiconductor module 2, the DC voltage of the DC power supply 80 is converted into an AC voltage, and the three-phase AC motors 81 and 82 are driven.

  Of the two three-phase AC motors 81 and 82, one three-phase AC motor 81 has high power consumption, and the other three-phase AC motor 82 has low power consumption. One three-phase AC motor 81 is connected to the high-current semiconductor module 2a, and the other three-phase AC motor 82 is connected to the small-current semiconductor module 2b.

On the other hand, as shown in FIG. 1, the power conversion device 1 of this example includes a capacitor 5 for smoothing a DC voltage. The capacitor 5 includes a capacitor element 50 and a sealing member 500 that seals the capacitor element 50. Both end surfaces of the capacitor element 50 in the Z direction are electrode surfaces 53 and 54.
The positive electrode bus bar 3 and the negative electrode bus bar 4 include extended portions 38 and 48 extending in the Z direction from the substrate portions 30 and 40, and capacitor connecting portions 39 and 49 protruding in the Y direction from the extended portions 38 and 48. With. The capacitor connecting portions 39 and 49 are connected to the electrode surfaces 53 and 54 of the capacitor 5.

  As shown in FIGS. 4 and 5, the terminal connection portions 32 and 42 of the bus bars 3 and 4 include projecting portions 33 and 43 that project in the Z direction. The protrusions 33 and 43 are superposed on the power terminal 21 and welded.

  As shown in FIG. 5, in this example, the positive bus bar 3 is formed by overlapping two bus bar pieces 30 (30a, 30b). Similarly, the negative electrode bus bar 4 is formed by overlapping two bus bar pieces 40 (40a, 40b). Of these bus bar pieces 30 and 40, one of the bus bar pieces 30a and 40a has terminal connection portions 32 and 42 connected to the high-current semiconductor module 2a. The other bus bar pieces 30b and 40b have terminal connection portions 32 and 42 connected to the small current semiconductor module 2b.

As shown in FIGS. 1 and 2, the large current substrate portion 31 a and the small current substrate portion 31 b constituting the positive electrode bus bar 3 are overlapped in the Z direction. These substrate portions 31a and 31b are made of metal, and a natural oxide film is formed on the surface thereof. Further, since the large current substrate portion 31a and the small current substrate portion 31b are left with distortions formed during manufacture or stress is applied during assembly, the surfaces thereof are not completely flat surfaces. Therefore, a gap is formed between the two substrate portions 31a and 31b. For these reasons, the two substrate portions 31a and 31b are not electrically connected to each other over the entire surface, but are relatively insulated. For this reason, the large current substrate portion 31a and the small current substrate portion 31b have many portions where current flows separately. The two substrate portions 31a and 31b have different current densities. The large current substrate portion 41a and the small current substrate portion 41b of the negative electrode bus bar 3 have the same structure.
For these reasons, the values of the parasitic inductance L attached to the large current substrate portions 31a and 41a and the parasitic inductance L attached to the small current substrate portions 31b and 41b are different from each other. As shown in FIG. 2, since the interval D1 between the large current substrate portions 31a and 41a is narrow, the parasitic inductance L attached to the large current substrate portions 31a and 41a is small. Moreover, since the space | interval D2 of the small current board parts 31b and 41b is wide, the parasitic inductance L attached to the small current board parts 31b and 41b is large.

  In addition, the two board | substrate parts 31a and 31b which comprise the positive electrode bus bar 3 are fastened with the volt | bolt which is not shown in figure. As a result, the two board portions 31a and 31b are integrated, and the two board portions 31a and 31b are electrically connected at the site where the bolts are fastened. The substrate portions 31a and 31b can be connected to each other by press caulking or welding in addition to bolt fastening. Further, the two substrate portions 41 a and 41 b of the negative electrode bus bar 4 have the same structure as the positive electrode bus bar 3.

  On the other hand, as shown in FIG. 1, a through hole 499 penetrating in the Z direction is formed in the substrate portion 41 of the negative electrode bus bar 4. The power terminal 21 (positive electrode terminal 21 a) of the semiconductor module 2 passes through the through hole 499 and is connected to the positive electrode bus bar 3.

  The power terminal 21 of the semiconductor module 2 includes a positive terminal 21a connected to the positive bus bar 3, a negative terminal 21b connected to the negative bus bar 4, and an AC terminal electrically connected to the three-phase AC motors 81 and 82 (see FIG. 19). 21c. In addition, the semiconductor module 2 has a control terminal 22 protruding from the main body 20. The control terminal 22 is connected to the control circuit board 19. This control circuit board 19 controls the switching operation of the semiconductor module 2.

  As shown in FIG. 18, in this example, the stacked body 10 is configured by alternately stacking the semiconductor modules 2 and the cooling pipes 11. Two cooling pipes 11 adjacent to each other in the X direction are connected by connecting pipes 15 at both ends in the Y direction. In addition, among the plurality of cooling pipes 11, an inlet pipe 12 for introducing the refrigerant 14 and an outlet pipe 13 for leading the refrigerant 14 are connected to the cooling pipe 11 a positioned at one end in the X direction. Yes. When the refrigerant 14 is introduced from the introduction pipe 12, the refrigerant 14 flows through all the cooling pipes 11 through the connecting pipe 15 and is led out from the outlet pipe 13. Thereby, the semiconductor module 2 is configured to be cooled.

  Further, a pressure member 17 (plate spring) is interposed between the laminate 10 and the wall portion 161 of the case 16. The pressing member 17 presses the laminate 10 toward the other wall 162 of the case 16. Thereby, the laminated body 10 is fixed in the case 16 while ensuring a contact pressure between the semiconductor module 2 and the cooling pipe 11.

Next, a method for manufacturing the positive electrode bus bar 3 will be described. First, as shown in FIG. 6, a metal plate is processed to form a member 306 including a plate-like portion 316 and a plurality of comb-like portions 321. Then, the comb-like portion 321 is bent along a predetermined bending line F to form the protruding portion 33 as shown in FIG. Further, the plate-like portion 316 is bent at two places to form the substrate portion 31 (large current substrate portion 31a), the extending portion 38, and the capacitor connecting portion 39. Thereby, one bus-bar piece 30a is manufactured.
Similarly, as shown in FIGS. 8 and 9, another metal plate is processed to produce the other bus bar piece 30b.

  Thereafter, as shown in FIGS. 10 and 11, two terminal connection portions 32a formed on one bus bar piece 30a and two terminal connection portions 32b formed on the other bus bar piece 30b are not adjacent to each other in the X direction. The bus bar pieces 30a and 30b are overlapped. In the overlapped state, a gap S is formed between the terminal connecting portion 32 and the adjacent protruding portion 33. The positive electrode terminal 21a (see FIG. 3) is inserted into the gap S.

Next, a method for manufacturing the negative electrode bus bar 4 will be described. As shown in FIG. 12, first, a metal plate is processed to form a member 405 including a plate-like portion 415 and a plurality of comb-tooth-like portions 420. A through hole 499 is formed in the plate member 415. Then, the comb-shaped portion 420 is bent along a predetermined bending line F to form the protruding portion 43 as shown in FIG. Further, the plate-like portion 415 is bent at two places to form the substrate portion 41 (large current substrate portion 41a), the extending portion 48, and the capacitor connecting portion 49. Thereby, one bus-bar piece 40a is manufactured.
Similarly, as shown in FIGS. 14 and 15, another metal plate is processed to produce the other bus bar piece 40b.

  Thereafter, as shown in FIGS. 16 and 17, two terminal connection portions 42a formed on one bus bar piece 40a and two terminal connection portions 42b formed on the other bus bar piece 40b are not adjacent to each other in the X direction. The bus bar pieces 40a and 40b are overlapped. In the overlapped state, a gap S is formed between the terminal connection portion 42 and the adjacent protrusion 43. In this gap S, the negative electrode terminal 21b (see FIG. 3) is inserted.

The effect of this example will be described. As shown in FIG. 3, in this example, the board portions 31a and 31b are overlapped so that the terminal connection portions 32 formed on the same bus bar piece 30 (30a and 30b) are not adjacent in the X direction. The positive electrode bus bar 3 is configured. The negative electrode bus bar 4 has the same configuration.
In this example, the positive electrode bus bar 3 with a narrow pitch of the terminal connection portions 32 can be easily manufactured. That is, it is difficult to manufacture the positive electrode bus bar 3 with a narrow pitch of the terminal connection portions 32 by pressing one metal plate or the like, but the bus bar piece 30 with a wide pitch of the terminal connection portions 32 is easy to manufacture. is there. In this example, as shown in FIGS. 6 to 11, a plurality of bus bar pieces 30 having a wide pitch between the terminal connection portions 32 are manufactured, and the plurality of bus bar pieces 30 (30a, 30b) are combined and combined. In this state, the pitch of the terminal connection portions 32 can be reduced. Therefore, it is possible to easily manufacture the positive electrode bus bar 3 in which the pitch of the terminal connection portions 32 is narrow. Similarly, in this example, the negative electrode bus bar 4 in which the pitch of the terminal connection portions 42 is narrow can be easily manufactured.
Moreover, if it is set as the said structure, the width | variety (X direction length) of each terminal connection part 32 and 42 can be lengthened. Therefore, the self inductance of the bus bars 3 and 4 can be reduced.

In this example, the surge voltage applied to the semiconductor element 29 included in the large current semiconductor module 2a can be reduced. That is, in this example, as shown in FIG. 2, since the distance D1 between the two large current substrate portions 31a and 41a is narrowed, the parasitic inductance L between the large current substrate portions 31a and 41a is reduced. Can do. The semiconductor element 29 in the large current semiconductor module 2a has a large amount of time change dI / dt of the current I at the time of current interruption, but since the parasitic inductance L attached to the large current substrate portions 31a and 41a is small, the surge voltage V (= LdI / dt) need not be particularly large.
Further, in this example, as shown in FIG. 2, since the distance D2 between the two small current substrate portions 31b and 41b is relatively wide, a parasitic inductance L between the small current substrate portions 31b and 41b is obtained. Tends to grow. However, since the semiconductor element 29 in the small current semiconductor module 2b has a small time variation dI / dt of the current I at the time of current interruption, the surge voltage V (= LdI / dt) applied to the semiconductor element 29 is particularly large. I'm sorry.

  As described above, according to this example, it is possible to easily manufacture a positive electrode bus bar and a negative electrode bus bar with a narrow pitch of terminal connection portions, and to suppress the application of a large surge voltage to a semiconductor element through which a large current flows. A conversion device can be provided.

(Example 2)
In this example, the shape of the bus bars 3 and 4 is changed. As shown in FIG. 20, the power conversion device 1 of this example is configured such that one terminal connection portion 32 included in the positive electrode bus bar 3 is connected to two power terminals 21 adjacent in the X direction. As shown in FIGS. 20 and 21, the terminal connection portion 32 of the positive electrode bus bar 3 includes a protruding portion 33 protruding in the Z direction. The protrusions 33 are respectively formed at both ends of the single protrusion 33 in the X direction. This protrusion 33 is superposed on the power terminal 21 and welded. The negative electrode bus bar 4 has the same structure.

  If it does in this way, even if there are few terminal connection parts 32 and 42, it will become possible to connect to many power terminals 21. FIG. Therefore, the structure of the bus bars 3 and 4 can be simplified, and the manufacturing cost of the bus bars 3 and 4 can be reduced.

  Others are the same as in the first embodiment. Moreover, among the symbols used in the drawings relating to this example, the same symbols as those used in the first embodiment represent the same components as those in the first embodiment unless otherwise indicated.

Example 3
In this example, the structure of the bus bars 3 and 4 is changed. As shown in FIG. 22, in this example, three bus bar pieces 30 (30a to 30c) are overlapped to form the positive electrode bus bar 3. Similarly, the negative electrode bus bar 4 is formed by superimposing three bus bar pieces 40 (40a to 40c).

  As in the first embodiment, the semiconductor module 2 of this example includes a large current semiconductor module 2a and a small current semiconductor module 2b. In addition, the semiconductor module 2 of this example includes a medium current semiconductor module 2c in which the amount of current flowing through the semiconductor element is about the middle between the large current semiconductor module 2a and the small current semiconductor module 2b.

  Similarly to the first embodiment, the substrate portions 31 and 41 of this example include large current substrate portions 31a and 41a connected to the large current semiconductor module 2a and small current substrate portions 31b and 41b connected to the small current semiconductor module 2b. There is. In addition, the substrate portions 31 and 41 of this example include medium current substrate portions 31c and 41c connected to the medium current semiconductor module 2c.

  An interval D1 between the large current substrate portions 31a and 41a in the Z direction is narrower than an interval D2 between the small current substrate portions 31b and 41b. Further, the distance D3 between the medium current substrate portions 31c and 41c in the Z direction is wider than the distance D1 and narrower than the distance D2. That is, D1 <D3 <D2.

  In this way, the parasitic inductance L1 attached to the large current substrate portions 31a and 41a is reduced, and the parasitic inductance L2 attached to the small current substrate portions 31b and 41b is increased. In addition, the parasitic inductance L3 attached to the medium current board portions 31c and 41c is a value approximately in the middle of the two parasitic inductances L1 and L2. Therefore, the surge voltage applied to the three types of semiconductor modules 2 (2a, 2b, 2c) can be equalized.

  Others are the same as in the first embodiment. Moreover, among the symbols used in the drawings relating to this example, the same symbols as those used in the first embodiment represent the same components as those in the first embodiment unless otherwise indicated.

Example 4
In this example, the structure of the bus bars 3 and 4 is changed. As shown in FIG. 23, in this example, three bus bar pieces 30 are overlapped to form the positive electrode bus bar 3. Similarly, the negative electrode bus bar 4 is formed by superimposing three bus bar pieces 40.

  As in the first embodiment, the semiconductor module 2 of this example includes a large current semiconductor module 2a and a small current semiconductor module 2b. The ratio of the number of large current semiconductor modules 2a and small current semiconductor modules 2b is 2: 1.

  Of the three substrate portions 31 constituting the positive electrode bus bar 3, the two substrate portions 31 are large current substrate portions 31a connected to the large current semiconductor module 2a. The remaining one substrate portion 31 is a small current substrate portion 31b connected to the small current semiconductor module 2b. Similarly, of the three substrate portions 41 constituting the negative electrode bus bar 4, two substrate portions 41 are large current substrate portions 41a, and one substrate portion 41 is a small current substrate portion 41b.

  The interval D1 between the large current substrate portions 31a and 41a in the Z direction is equal to each other for the two large current semiconductor modules 2a. Further, the distance D2 between the small current substrate portions 31b and 41b in the Z direction is wider than the distance D1.

  With the above configuration, the number of large current semiconductor modules 2a can be made larger than the number of small current semiconductor modules 2b while reducing the surge voltage applied to the large current semiconductor module 2a. Therefore, the current flowing through the large current semiconductor module 2a can be dispersed, and it is possible to prevent an excessively large current from flowing through each large current semiconductor module 2a.

  Others are the same as in the first embodiment. Moreover, among the symbols used in the drawings relating to this example, the same symbols as those used in the first embodiment represent the same components as those in the first embodiment unless otherwise indicated.

DESCRIPTION OF SYMBOLS 1 Power converter 10 Laminate body 2 Semiconductor module 2a Large current semiconductor module 2b Small current semiconductor module 20 Main part 21 Power terminal 3 Positive electrode bus bar 30a, 30b Bus bar piece 31 Substrate part 31a Large current substrate part 31b Small current substrate part 32 Terminal connection Part 4 Negative bus bar 40a, 40b Bus bar piece 41 Board part 41a High current board part 41b Small current board part 42 Terminal connection part

Claims (3)

A stack in which a plurality of semiconductor modules (2) having power terminals (21) projecting from a main body (20) containing a semiconductor element (29) are stacked with each of the power terminals (21) facing in the same direction. Body (10);
A positive bus bar (3) and a negative electrode bus bar (4), each of which is electrically connected to the semiconductor module (2) and receives a DC voltage between them;
The positive electrode bus bar (3) and the negative electrode bus bar (4) are composed of a plurality of bus bar pieces (30, 40) overlapped with each other, and each of the bus bar pieces (30, 40) has its main surface (310 , 410) are arranged so as to be orthogonal to the protruding direction of the power terminal (21), the stacking direction of the stacked body (10) and the protruding from the substrate section (31, 41). A plurality of terminal connecting portions (32, 42) extending in the width direction orthogonal to both the direction and connected to the power terminal (21),
In the positive electrode bus bar (3) and the negative electrode bus bar (4), the terminal connection portions (32, 42) formed on the same bus bar piece (30, 40) are not adjacent to each other in the stacking direction. As described above, each of the above-mentioned substrate parts (31, 41) is configured to overlap,
The semiconductor module (2) includes a large current semiconductor module (2a) in which a current flowing in the semiconductor element (29) is relatively large, and a current flowing in the semiconductor element (29) from the large current semiconductor module (2a). There is a small current semiconductor module (2b) with low current,
The terminal connection portion (32) is connected to the substrate portion (31, 41) of the plurality of bus bar pieces (30, 40) constituting the positive electrode bus bar (3) and the negative electrode bus bar (4), respectively. There are a large current substrate part (31a, 41a) connected to the large current semiconductor module (2a) and a small current substrate part (31b, 41b) connected to the small current semiconductor module (2b),
The distance (D1) in the protruding direction between the large current substrate portion (31a) included in the positive electrode bus bar (3) and the large current substrate portion (41a) included in the negative electrode bus bar (4) is the positive electrode The distance between the small current substrate part (31b) included in the bus bar (3) and the small current substrate part (41b) included in the negative electrode bus bar (4) is narrower than the distance (D2) in the protruding direction. A power converter (1).   The positive electrode bus bar (3) and the negative electrode bus bar (4) are each formed by combining three bus bar pieces (30, 40), and the positive electrode bus bar (3) and the negative electrode bus bar (4) are respectively provided. Of the three substrate portions (31, 41) included, two of the substrate portions (31, 41) are the large current substrate portions (31a, 41a), and one of the substrate portions (31, 41). 41. The power converter according to claim 1, wherein 41) is the small current substrate portion (31b, 41b).   3. The power conversion according to claim 1, wherein one terminal connection portion (32, 42) is connected to two power terminals (21) adjacent to each other in the stacking direction. Device (1).

Images