JP6164122B2 - Power converter - Google Patents

Description

  The present invention relates to a power conversion device including a semiconductor module incorporating a semiconductor element and an AC 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 that includes a semiconductor module incorporating a semiconductor element and a plurality of bus bars connected to the semiconductor module is known. The plurality of bus bars include a DC bus bar serving as a current path between a DC power source and the semiconductor element, and an AC bus bar serving as a current path between the semiconductor element and an AC load. This power conversion device is configured to convert the DC power supplied from the DC power source into AC power by turning on and off the semiconductor element, and to drive the AC load with the AC power.

  The semiconductor module includes a main body portion incorporating the semiconductor element and a power terminal protruding from the main body portion. One end of the AC bus bar is welded to the power terminal. The other end of the AC bus bar is electrically connected to the AC load. In addition, a current sensor such as a Hall element is attached to the AC bus bar.

  In recent years, attempts have been made to reduce the thickness of the AC bus bar. When the AC bus bar is formed thin, for example, when the power terminal and the AC bus bar are welded, there is an advantage that the AC bus bar is easily melted by welding heat and the welding operation is facilitated.

JP2012-233741A

  However, since the electrical resistance increases when the AC bus bar is thinned, the resistance heat generated from the AC bus bar tends to increase when the power converter is used. For this reason, it becomes difficult to dispose electronic components such as current sensors that are sensitive to high temperatures in the vicinity of the AC bus bar. When such an electronic component is disposed in the vicinity of the AC bus bar, the temperature increases due to the resistance heat, and the life of the electronic component is likely to be reduced.

  The present invention has been made in view of such a background, and is intended to provide a power conversion device that can easily weld an AC bus bar to a power terminal of a semiconductor module and can arrange electronic components that are vulnerable to high temperatures in the vicinity of the AC bus bar. To do.

One aspect of the present invention is a semiconductor module having a main body portion incorporating a semiconductor element, and a power terminal electrically connected to the semiconductor element and protruding from the main body portion,
A plurality of alternating current bus bars welded to the power terminal and serving as a current path between the semiconductor element and an alternating load;
Each of the AC bus bars connects the first connection part welded to the power terminal, the second connection part for electrical connection to the AC load, the first connection part, and the second connection part. A connecting portion,
At least some of the AC bus bars among the plurality of AC bus bars are formed with a thick part thicker than the first connection part in the connection part ,
A current sensor is provided at a position adjacent to the thick wall portion to measure a current value of a current flowing through each of the AC bus bars by measuring a magnetic field generated around the thick wall portion. To power converter.

In the said power converter device, the said thick part thicker than a 1st connection part is formed in at least one part AC bus bar among several AC bus bars.
Therefore, a part (thick part) having a small electrical resistance can be formed in the AC bus bar while reducing the thickness of the first connection part. Therefore, it is possible to reduce the resistance heat generated from the thick portion when the power converter is used, and it is possible to arrange an electronic component that is vulnerable to high temperatures in the vicinity of the thick portion. In other words, since the thick-walled portion is unlikely to generate large resistance heat, even if an electronic component is placed near the thick-walled portion, the temperature of the electronic component can be prevented from rising due to the resistance heat, and the life of the electronic component can be reduced. It can suppress that it falls.

  Moreover, since the said 1st connection part of an alternating current bus bar is thinner than a thick part, when performing the operation | work which welds a 1st connection part to a power terminal, a 1st connection part is carried out for a short time by welding heat. Can be melted. Therefore, it is possible to more easily perform the welding operation between the first connection portion and the power terminal.

  As described above, according to the present invention, it is possible to provide a power converter capable of easily welding an AC bus bar to a power terminal of a semiconductor module and arranging electronic components that are vulnerable to high temperatures in the vicinity of the AC bus bar.

It is sectional drawing of the power converter device in Example 1, Comprising: II sectional drawing of FIG. II-II sectional drawing of FIG. FIG. 3 is a plan view of an AC bus bar, a core, and a current sensor in Embodiment 1, with a sealing portion omitted. IV-IV sectional drawing of FIG. VV sectional drawing of FIG. The manufacturing method explanatory drawing of the alternating current bus bar in Example 1. FIG. The figure following FIG. VIII-VIII sectional drawing of FIG. IX-IX sectional drawing of FIG. XX sectional drawing of FIG. Explanatory drawing of the process of welding an alternating current bus bar to a power terminal in Example 1. FIG. XII-XII sectional drawing of FIG. The circuit diagram of the power converter device in Example 1. FIG. The manufacturing method explanatory drawing of the alternating current bus bar in Example 2. FIG. XV-XV sectional drawing of FIG. The figure following FIG. XVII-XVII sectional drawing of FIG. The top view of the alternating current bus bar in Example 3. FIG. XIX-XIX sectional drawing of FIG. Explanatory drawing of the manufacturing method of the alternating current bus bar in Example 4. FIG. The figure following FIG. XXII-XXII sectional drawing of FIG. The perspective view of the alternating current bus bar which formed the thick part in Example 5 so that it might be biased to the one side of the connection part in a X direction. The perspective view of the alternating current bus bar which formed the thick part in Example 5 in the center of the connection part in a X direction. The perspective view of the alternating current bus bar which formed the thick part in Example 5 in the center of the connection part in a Y direction. The perspective view of the alternating current bus bar which formed the thick part in Example 5 in the both sides of the connection part in a X direction, respectively. The top view of an alternating current bus bar, a core, and a current sensor in a comparative example. XXVIII-XXVIII sectional drawing of FIG. XXIX-XXIX sectional drawing of FIG.

  The power conversion device can be a vehicle-mounted power conversion device to be mounted on a vehicle such as an electric vehicle or a hybrid vehicle.

Example 1
The Example which concerns on the said power converter device is described using FIGS. As shown in FIGS. 1 and 2, the power conversion device 1 of this example includes a semiconductor module 2 and a plurality of AC bus bars 3 (3a, 3b, 3c). The semiconductor module 2 includes a main body 20 that contains a semiconductor element 21 (see FIG. 13), and a power terminal 22 that is electrically connected to the semiconductor element 21 and protrudes from the main body 20. The AC bus bar 3 is welded to the power terminal 22 (22a). The AC bus bar 3 is a current path between the semiconductor element 21 and the AC load 80 (see FIG. 13).

As shown in FIG. 3, each AC bus bar 3 includes a first connection part 31 welded to the power terminal 22, a second connection part 32 for electrical connection to an AC load 80 (see FIG. 13), and a first It has the connection part 33 which connects the connection part 31 and the 2nd connection part 32. FIG.
As shown in FIG. 2, in some of the AC bus bars 3 a, 3 b among the plurality of AC bus bars 3 a, 3 b, 3 c, a thick portion 34 that is thicker than the first connection portion 31 is formed in the connecting portion 33. Has been.

  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. 1, the power conversion apparatus 1 of this example includes a pair of DC bus bars 11 (a positive bus bar 11p and a negative bus bar 11n) in addition to the AC bus bars 3 (3a, 3b, 3c). A DC voltage of a DC power source 8 (see FIG. 13) is applied to the semiconductor module 2 via the DC bus bar 11. Then, the semiconductor element 21 is turned on / off to convert DC power into three-phase AC power, and this three-phase AC power is supplied to the AC load 80 via the AC bus bar 3.

  As shown in FIG. 2, the thick part 34 is formed in two AC bus bars 3 (3a, 3b) among the three AC bus bars 3 (3a, 3b, 3c). A current sensor 4 for measuring a current value of a current I (see FIG. 3) flowing through each AC bus bar 3 is disposed at a position adjacent to the thick portion 34.

  As shown in FIGS. 3 and 4, the first connection portion 31 of the AC bus bar 3 is formed in a flat plate shape. In this example, as will be described later, the first connecting portion 31 is welded to the power terminal 22 by laser welding. Further, a bolt insertion hole 320 is formed in the second portion 32. A connector (not shown) is overlapped on the second connection portion 32 and a bolt is inserted into the bolt insertion hole 320 so that the second connection portion 32 is fastened to the connector. The AC bus bar 3 is electrically connected to the AC load 80 via this connector.

  As shown in FIGS. 4 and 5, in this example, the thick portion 34 is formed by overlapping the metal plates 38. The current sensor 4 is arranged at a position adjacent to the thick portion 34 in the thickness direction (Z direction) of the AC bus bar 3. In addition, a magnetic collecting core 40 is provided so as to surround the thick portion 34. The core 40 is made of a magnetic material such as ferrite and has an annular shape. A gap G is formed in the core 40. A current sensor 4 is arranged in the gap G.

  The current sensor 4 is formed by a Hall element. When an electric current flows through the AC bus bar 3, a magnetic field is generated around the thick portion 34 due to the electric current. The magnetic field is collected using the core 40 and the current sensor 4 is used to detect the strength of the magnetic field. Thus, the current value of the current I flowing through the AC bus bar 3 is measured. The current sensor 4 includes a sensor main body 48 incorporating a Hall element, and a signal terminal 49 protruding from the sensor main body 48. The signal terminal 49 is connected to a control circuit board 7 described later by a wire (not shown).

  When the AC bus bar 3 is manufactured, first, a metal plate 38 having the shape shown in FIG. 6 is prepared. Then, the metal plate 38 is bent along the planned bending line 380, and the two overlapped portions 340 are overlapped with each other as shown in FIGS. A portion where the two overlapped portions 340 are overlapped becomes the thick portion 34.

  As shown in FIG. 1, the semiconductor module 2 includes a control terminal 23 in addition to the main body 20 and the power terminal 22. The control terminal 23 protrudes from the main body 20. The control circuit board 7 is connected to the control terminal 23. The control circuit board 7 is used to control the switching operation of the semiconductor element 21 (IGBT element: see FIG. 13) in the main body 20.

  As shown in FIG. 1, the power terminal 22 includes a positive terminal 22p and a negative terminal 22n to which a DC voltage is applied, and an AC terminal 22a that outputs AC power. The positive electrode bus bar 11p is welded to the positive electrode terminal 22p, and the negative electrode bus bar 11n is welded to the negative electrode terminal 22n. Further, the AC bus bar 3 described above is welded to the AC terminal 22a. The positive electrode bus bar 11p and the negative electrode bus bar 11n are laser-welded to the power terminal 22 in the same manner as the AC bus bar 3.

As shown in FIGS. 11 and 12, when the AC terminal 22 a and the AC bus bar 3 are welded, first, the front end surface 220 of the AC terminal 22 a is brought into contact with one main surface 310 of the first connection portion 31. Then, the other main surface 311 of the first connection portion 31 is irradiated with the laser beam L. Thereby, the 1st connection part 31 and AC terminal 22a are welded. Similarly, the positive electrode bus bar 11p and the negative electrode bus bar 11n are welded to the positive electrode terminal 22p and the negative electrode terminal 22n using the laser beam L, respectively. A through hole 119 is formed in the positive bus bar 11p. The laser beam L is irradiated to the negative electrode bus bar 11n through the through hole 119.
In this example, the “main surface” means the surface having the largest area among the surfaces of the first connection portion 31.

  As shown in FIGS. 9 and 10, in this example, a stacked body 10 is formed by stacking a plurality of semiconductor modules 2 and a plurality of cooling pipes 6. Two cooling pipes 6 adjacent to each other in the stacking direction (X direction) of the stacked body 10 are connected by a connecting pipe 60. In addition, among the plurality of cooling pipes 6, the end cooling pipe 6 a positioned at one end in the X direction has an introduction pipe 15 for introducing the refrigerant 17 and an outlet pipe 16 for leading out the refrigerant 17. And are connected. When the refrigerant 17 is introduced into the introduction pipe 15, the refrigerant 17 flows through all the cooling pipes 6 through the connecting pipe 60 and is led out from the outlet pipe 16. Thereby, the semiconductor module 2 is configured to be cooled.

  A pressing member 14 (leaf spring) is disposed at a position adjacent to the stacked body 10 in the X direction. Using this pressurizing member 14, the laminate 10 is pressed toward the wall 121 of the case 12. Thereby, the laminated body 10 is fixed in the case 12, and the contact pressure between the cooling pipe 6 and the semiconductor module 2 is secured.

  As shown in FIG. 1, a capacitor 5 is disposed at a position adjacent to the stacked body 10 in the width direction (Y direction) orthogonal to both the X direction and the Z direction. The positive electrode bus bar 11p and the negative electrode bus bar 11n described above are connected to terminals 530 and 540 of the capacitor 5, respectively. The capacitor 5 is used to smooth the DC voltage of the DC power supply 8 (see FIG. 13).

  The capacitor 5 includes a capacitor case 50, a capacitor element 51 disposed in the capacitor case 50, a sealing member 52 that seals the capacitor element 51 in the capacitor case 50, and electrode surfaces 511 of the capacitor element 51. And electrode plates 53 and 54 connected to 512 respectively. Part of the electrode plates 53 and 54 protrudes from the sealing member 52 and serves as the terminals 530 and 540.

The effect of this example will be described. In this example, as shown in FIGS. 2 and 4, at least some of the AC bus bars 3 a and 3 b among the plurality of AC bus bars 3 (3 a, 3 b, 3 c) are provided with thicker portions 34 that are thicker than the first connection portion 31. It is formed.
Therefore, it is possible to form a portion (thick portion 34) having a small electric resistance in the AC bus bar 3 while reducing the thickness of the first connection portion 31. Therefore, it is possible to reduce the resistance heat generated from the thick portion 34 when the power conversion device 1 is used, and it is possible to dispose electronic components sensitive to high temperatures such as the current sensor 4 in the vicinity of the thick portion 34. . That is, since the thick portion 34 is unlikely to generate a large resistance heat, even if an electronic component is disposed in the vicinity of the thick portion 34, the temperature of the electronic component can be prevented from rising due to the resistance heat. It can suppress that a lifetime falls.

  Moreover, since the 1st connection part 31 of the alternating current bus bar 3 is thinner than the thick part 34, when performing the operation | work which welds the 1st connection part 31 to the power terminal 22, a 1st connection is carried out by welding heat. The part 22 can be melted in a short time. Therefore, the welding operation between the first connection portion 31 and the power terminal 22 can be performed more easily.

  As shown in FIGS. 1 and 4, in this example, the current sensor 4 is provided at a position adjacent to the thick portion 34. The current sensor 4 is an electronic component whose life is likely to be particularly shortened at a high temperature. However, in this example, the thick portion 34 having a small resistance heat is formed on the AC bus bar 3, so the vicinity of the thick portion 34 is used. In addition, the temperature sensor 4 can be arranged.

  Moreover, as shown in FIGS. 1-5, in this example, the cyclic | annular core 40 which consists of magnetic bodies is provided so that the thick part 34 may be surrounded. The magnetic characteristics of the core 40 may change as the temperature rises. Therefore, when the temperature of the core 40 rises greatly, the magnetic characteristics may change, and the current measured value by the current sensor 4 may be inaccurate. However, if the core 40 is provided so as to surround the thick portion 34 where the temperature does not easily rise as in this example, the temperature of the core 40 can be prevented from greatly increasing, and the magnetic characteristics of the core 40 change. Defects can be suppressed. Therefore, the current value can be accurately measured by the current sensor 4.

  As shown in FIGS. 27 to 29, the AC bus bar 93 is not formed with a thick portion, and a wide portion 99 having a locally wide width W in the X direction is formed so as to surround the thick portion 99. A core 940 can also be provided. However, in this case, the core 940 is increased in size, and there is a problem that the manufacturing cost of the core 940 is increased. Further, there may be a problem that the core 940 interferes with other parts. However, if the core 40 is provided so as to surround the thick portion 34 formed in the AC bus bar 3 as in this example (see FIG. 5), the core 40 can be prevented from becoming large, and the manufacturing cost of the core 40 can be suppressed. Can be reduced. In addition, it is difficult for the core 40 to interfere with other parts.

In addition, as shown in FIGS. 11 and 12, in this example, the first connection portion 31 and the power terminal 22 are in a state where the power terminal 22 is in contact with one main surface 310 of the first connection portion 31 of the AC bus bar 3. Are laser welded.
Therefore, the welding operation between the power terminal 22 and the first connection portion 31 can be easily performed. That is, if laser welding is performed as described above, it is not necessary to weld the power terminal 22 to a specific position of the main surface 310, and it is possible to weld the power terminal 22 to an arbitrary position within the main surface 310. That is, even when the position of the power terminal 22 is shifted, welding can be performed by irradiating the shifted position with the laser beam L. Therefore, it becomes easy to allow position shift of power terminal 22, and it becomes possible to perform welding work of power terminal 22 and the 1st connection part 31 easily. In this example, as shown in FIG. 9, the semiconductor module 2 and the cooling pipe 6 are laminated to form the laminated body 10, so that the thickness variations of the semiconductor module 2 and the cooling pipe 6 are stacked, and the power in the X direction is increased. The terminal 22 is likely to be displaced. However, if laser welding is performed as in this example, the power terminal 22 and the first connecting portion 31 can be easily welded even if the position of the power terminal 22 is shifted.

  Laser welding is a welding method that can concentrate energy in a narrow range, but the total amount of heat generated is relatively small. For this reason, if the thickness of the first connection portion 31 is large, the first connection portion 31 is difficult to melt, and the welding operation cannot be performed in a short time. Therefore, when performing laser welding, it is necessary to make the thickness of the 1st connection part 31 thin. In the AC bus bar 3 of this example, the portion where the current sensor 4 is arranged can be thick, and the first connection portion 31 for performing laser welding can be thin. Therefore, the AC bus bar 3 of this example can be suitably used when laser welding is performed.

  As described above, according to this example, it is possible to provide a power converter that can easily weld an AC bus bar to a power terminal of a semiconductor module and can arrange an electronic component that is vulnerable to high temperatures in the vicinity of the AC bus bar.

  In this example, of the three AC bus bars 3 (3a, 3b, 3c), the two AC bus bars 3a, 3b are formed with thick portions 34, and the current sensors 4 are connected to the respective thick portions 34. However, the present invention is not limited to this. For example, the thick portion 34 may be formed only in one AC bus bar 3 of the three AC bus bars 3, and the current sensor 4 may be disposed in the thick portion 34. Moreover, the thick part 34 may be formed in all the three AC bus bars 3, and the current sensor 4 may be provided in each thick part 34.

  In this example, a Hall element is used as the current sensor 4, but the present invention is not limited to this. That is, for example, a GMR element (Giant Magneto Resistive element) can be used as the current sensor 4. In this case, the magnetic collecting core 40 is not necessary.

(Example 2)
In this example, the method for manufacturing the AC bus bar 3 is changed. As shown in FIGS. 14 and 15, in this example, first, a single metal plate 38 having the same thickness as the thick portion 34 is prepared. Then, by forging, both ends 319 and 329 of the metal plate 38 are thinned as shown in FIGS. Further, the bolt insertion hole 320 is formed in the end portion 329 on the side that becomes the second connection portion 32. Thereby, the AC bus bar 3 of this example is obtained.

In this example, the thick portion 34 is formed between the first connection portion 31 and the second connection portion 32, that is, in all the portions of the coupling portion 33.
In addition, the configuration and operational effects are the same as those of the first embodiment.

(Example 3)
In this example, the shape of the AC bus bar 3 is changed. As shown in FIGS. 18 and 19, in the AC bus bar 3 of this example, only the first connection portion 31 of the first connection portion 31 and the second connection portion 32 is thinly formed. The second connection part 32 is formed to have the same thickness as the thick part 34.
In addition, the configuration and operational effects are the same as those of the first embodiment.

Example 4
In this example, the method for manufacturing the AC bus bar 3 is changed. As shown in FIGS. 20 to 22, in this example, first, two metal plates 38a and 38b having the same thickness are prepared. Then, the end portions 382 and 383 of the respective metal plates 38a and 38b are overlapped and welded. Thereby, the thick part 34 is formed. The end 381 on the opposite side of the thick part 34 in the one metal plate 38 a becomes the first connection part 31. Further, a bolt insertion hole 320 is formed at the end 384 opposite to the thick portion 34 in the other metal plate 38b. As a result, the end 384 serves as the second connection portion 32.
In addition, the configuration and operational effects are the same as those of the first embodiment.

(Example 5)
In this example, the shape of the AC bus bar 3 is changed. As shown in FIG. 23, in this example, the thick portion 34 is formed only on one side of the connecting portion 33 in the X direction. The thick portion 34 is formed in an elongated shape in the Y direction. A portion 334 on the other side in the X direction of the connecting portion 33 is formed to have the same thickness as the first connecting portion 31 and the second connecting portion 32.

  Moreover, you may form the alternating current bus bar 3 in the shape shown in FIG. The AC bus bar 3 has a thick portion 34 formed only at the center of the connecting portion 33 in the X direction. The portions 335 and 336 located on both sides in the X direction of the connecting portion 33 are formed to have the same thickness as the first connecting portion 31 and the second connecting portion 32.

  Moreover, as shown in FIG. 25, you may form the thick part 34 only in the center part in the Y direction of the connection part 33. As shown in FIG. This AC bus bar 3 is formed by forging. That is, a metal plate 38 (not shown) having the same thickness as that of the thick portion 34 is prepared, and forging is performed to reduce the portion other than the thick portion 34. In this way, the AC bus bar 3 shown in FIG. 25 is formed.

  Moreover, as shown in FIG. 26, you may form the thick part 34 in the both sides in the X direction of the connection part 33, respectively. In this AC bus bar 3, the two thick portions 34 are each formed in an elongated shape in the Y direction. Further, a portion 339 between the two thick portions 34 of the connecting portion 33 has the same thickness as the first connection portion 31 and the second connection portion 32.

  In addition, the configuration and operational effects are the same as those of the first embodiment.

DESCRIPTION OF SYMBOLS 1 Power converter 2 Semiconductor module 20 Main-body part 21 Semiconductor element 22 Power terminal 3 AC bus bar 31 1st connection part 32 2nd connection part 33 Connection part 34 Thick part 80 AC load

Claims (3)

A semiconductor module (2) having a main body (20) containing a semiconductor element (21) and a power terminal (22) projecting from the main body (20) and electrically connected to the semiconductor element (21);
A plurality of AC bus bars (3) welded to the power terminal and serving as a current path between the semiconductor element (21) and the AC load (80);
Each of the AC bus bars (3) includes a first connection part (31) welded to the power terminal (22), a second connection part (32) for electrical connection to the AC load (80), A connecting portion (33) for connecting the first connecting portion (31) and the second connecting portion (32);
Among the plurality of AC bus bars (3a, 3b, 3c), at least some of the AC bus bars (3a, 3b) have a thickness greater than that of the first connection portion (31) at the connecting portion (33). A thick thick part (34) is formed ,
The current value of the current flowing through each AC bus bar (3a, 3b) is measured by measuring the magnetic field generated around the thick wall portion (34) at a position adjacent to the thick wall portion (34). A power converter (1) characterized in that a current sensor (4) is provided . An annular core (40) made of a magnetic material is provided so as to surround the thick portion (34), and the current sensor (4) is placed in a gap (G) formed in the core (40). The power conversion device ( 1 ) according to claim 1 , wherein the power conversion device ( 1 ) is arranged. With the power terminal (22) in contact with one main surface (310) of the first connection part (31), the first connection part (31) and the power terminal (22) are laser-welded. The power converter device (1) according to claim 1 or 2 , wherein the power converter device (1) is provided.

Images