JP2019088137A - Power conversion equipment - Google Patents

Power conversion equipment Download PDF

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Publication number
JP2019088137A
JP2019088137A JP2017215668A JP2017215668A JP2019088137A JP 2019088137 A JP2019088137 A JP 2019088137A JP 2017215668 A JP2017215668 A JP 2017215668A JP 2017215668 A JP2017215668 A JP 2017215668A JP 2019088137 A JP2019088137 A JP 2019088137A
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Japan
Prior art keywords
filter capacitor
semiconductor module
power
capacitor
pair
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Pending
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JP2017215668A
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Japanese (ja)
Inventor
和敏 塩見
Kazutoshi Shiomi
和敏 塩見
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株式会社デンソー
Denso Corp
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Priority to JP2017215668A priority Critical patent/JP2019088137A/en
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Abstract

A power conversion device capable of more efficiently reducing noise current is provided. A semiconductor module including a switching element, a pair of bus bars, a smoothing capacitor, and a filter capacitor are provided. The bus bar 3 connects the DC power supply 8 and the semiconductor module 2. The smoothing capacitor 4 and the filter capacitor 5 are each connected to a pair of bus bars 3. The pair of bus bars 3 are arranged to face each other at a predetermined interval. The filter capacitor 5 has a smaller capacitance than the smoothing capacitor 4. The filter capacitor 5 has a shorter current path length to the semiconductor module 2 than the smoothing capacitor 4. The filter capacitor 5 is disposed adjacent to the pair of bus bars 3. [Selection] Figure 1

Description

  The present invention relates to a power conversion device including a semiconductor module incorporating a switching element, a pair of bus bars, and a filter capacitor.
  One known power conversion device for converting DC power into AC power includes a semiconductor module incorporating a switching element, and a pair of bus bars electrically connecting the semiconductor module and a DC power supply (see Patent Document 1 below). reference). In this power converter, a smoothing capacitor and a filter capacitor are connected to the pair of bus bars. The smoothing capacitor is provided to smooth the DC voltage applied to the semiconductor module. In addition, the filter capacitor is provided to remove noise current generated from the semiconductor module.
  In the above power converter, the high frequency impedance of the filter capacitor is equal to or less than that of the smoothing capacitor. In this way, high frequency noise current easily flows to the filter capacitor. Thus, high frequency noise current is efficiently removed.
JP 2004-254355 A
  However, the power converter may not be able to sufficiently remove high frequency noise current. That is, in the above power converter, the filter capacitor may be disposed at a position away from the bus bar, and a large inductance L may be parasitic on a wire or the like connecting the filter capacitor and the bus bar. Therefore, when the frequency f of the noise current is increased, the impedance Z (= 2πfL) of the wiring or the like is increased, and the noise current is less likely to flow to the filter capacitor. Therefore, it is difficult to remove noise current having a high frequency f.
  The present invention has been made in view of the above problems, and an object of the present invention is to provide a power conversion device capable of reducing high frequency noise current more efficiently.
One aspect of the present invention is a power conversion device (1) that converts direct current power supplied from a direct current power supply (8) into alternating current power,
A semiconductor module (2) incorporating a switching element (20);
A pair of bus bars (3) of a positive bus bar (3 P ) connecting the positive electrode of the DC power supply and the semiconductor module, and a negative bus bar (3 N ) connecting the negative electrode of the DC power supply and the semiconductor module )When,
A smoothing capacitor (4) connected to the pair of bus bars for smoothing a DC voltage applied to the semiconductor module;
And a filter capacitor (5) smaller in electrostatic capacitance than the smoothing capacitor, connected to the pair of bus bars, and removing noise current generated from the semiconductor module,
The pair of bus bars are opposed to each other at a predetermined distance in the thickness direction of the bus bar,
The filter capacitor has a shorter current path length to the semiconductor module than the smoothing capacitor.
The filter capacitor is provided in the power conversion device disposed at a position adjacent to the pair of bus bars.
In the power converter, the filter capacitor is disposed at a position adjacent to the pair of bus bars.
Therefore, parasitic inductance L can be suppressed between the filter capacitor and the bus bar. Therefore, even for a noise current having a high frequency f, the impedance Z (= 2πfL) parasitic between the filter capacitor and the bus bar can be sufficiently reduced, and this noise current can easily flow to the filter capacitor. Therefore, it is easy to remove the noise current whose frequency f is high.
  In addition, when the above configuration is adopted, noise current can be easily removed by the filter capacitor, so that a filter capacitor with a small capacitance can be used. Therefore, a small size filter capacitor can be used, and the power converter can be easily miniaturized.
Further, in the above power converter, the pair of bus bars are disposed opposite to each other at a predetermined interval.
Therefore, the magnetic fields generated from the individual bus bars can be canceled each other, and the inductance parasitic on the pair of bus bars can be reduced. Therefore, a large inductance is less likely to be parasitic on a portion of the bus bar existing between the semiconductor module and the filter capacitor, and the impedance of this portion can be reduced. Therefore, the noise current generated from the semiconductor module can be easily flowed to the filter capacitor, and the noise current can be effectively removed.
As described above, according to this aspect, it is possible to provide a power conversion device that can reduce high frequency noise current more efficiently.
The reference numerals in parentheses described in the claims and the means for solving the problems indicate the correspondence with the specific means described in the embodiments described later, and the technical scope of the present invention is limited. It is not a thing.
FIG. 2 is a perspective view of the power conversion device viewed from the radiator side in the first embodiment. FIG. 2 is a perspective view of the inside of the power conversion device in the first embodiment. FIG. 2 is an enlarged perspective view of an essential part of the power conversion device in the first embodiment. IV arrow view of FIG. It is a perspective view of the power converter device seen from the alternator side in Embodiment 1, and except a sealing member. FIG. 2 is an enlarged plan view of an essential part of the power conversion device in the first embodiment. VII-VII sectional drawing of FIG. VIII-VIII sectional drawing of FIG. FIG. 1 is a circuit diagram of a power conversion device according to a first embodiment. FIG. 2 is a side view of the power conversion device and the alternator in the first embodiment. FIG. 7 is an enlarged plan view of an essential part of the power conversion device in which the arrangement position of the filter capacitor is changed in the first embodiment. FIG. 2 is an enlarged perspective view of an essential part of a power conversion device in which a plurality of filter capacitors are mounted on a capacitor substrate in the first embodiment. FIG. 10 is a perspective view of the power conversion device as viewed from the alternator side in the second embodiment. FIG. 7 is a circuit diagram of a power conversion device in a second embodiment. FIG. 13 is an enlarged cross-sectional view of main parts of the power conversion device according to the third embodiment. FIG. 16 is a perspective view of a power conversion device according to a fourth embodiment.
(Embodiment 1)
An embodiment according to the above power converter will be described with reference to FIGS. 1 to 12. The power conversion device 1 of this embodiment is used to convert DC power supplied from the DC power supply 8 (see FIG. 9) into AC power. As shown in FIGS. 5 and 9, the power conversion device 1 includes a semiconductor module 2, a pair of bus bars 3 (3 P and 3 N ), a smoothing capacitor 4, and a filter capacitor 5. The semiconductor module 2 incorporates the switching element 20.
The bus bar 3 includes a positive electrode bus bar 3 P and a negative electrode bus bar 3 N. The positive electrode bus bar 3 P connects the positive electrode of the DC power supply 8 to the semiconductor module 2. The negative bus bar 3 N connects the negative electrode of the DC power supply 8 to the semiconductor module 2.
The smoothing capacitor 4 and the filter capacitor 5 are connected to the pair of bus bars 3 (3 P , 3 N ). The smoothing capacitor 4 smoothes the DC voltage applied to the semiconductor module 2. The filter capacitor 5 is provided to remove noise current generated from the semiconductor module 2. The capacitance of the filter capacitor 5 is smaller than that of the smoothing capacitor 4.
As shown in FIG. 2 to FIG. 7, the pair of bus bars 3 are arranged in the thickness direction of the bus bar 3 so as to face each other at a predetermined interval. The filter capacitor 5 has a shorter current path length to the semiconductor module 2 than the smoothing capacitor 4.
The filter capacitor 5 is disposed adjacent to the pair of bus bars 3.
  As shown in FIG. 10, the power conversion device 1 of the present embodiment is attached to an alternator 81 (AC motor) of a vehicle. The alternator 81 is connected to an engine (not shown) via a belt 812. The alternator 81 is rotated using the driving force of the engine to generate electric power. Then, the obtained AC power is rectified using the switching element 20 (see FIG. 9), and the DC power supply 8 is charged.
  Further, when the engine is started, the DC power of the DC power supply 8 is converted into AC power using the power conversion device 1. Then, the alternator 81 is rotated using the obtained AC power. This starts the engine.
5, as shown in FIG. 9, the power conversion device 1 of the present embodiment includes three semiconductor modules 2 (2 A ~2 C). Each semiconductor module 2 incorporates four switching elements 20 (MOSFETs). And four switching elements 20 included in the first semiconductor module 2 A, by the two switching elements 20 included in the second semiconductor module 2 B, constitute a first power conversion circuit 10 A. Further, with the remaining two switching elements 20 included in the second semiconductor module 2 B, by the four switching elements 20 included in the third semiconductor module 2 C, constitutes a second power conversion circuit 10 B There is. Each power conversion circuit 10 includes three AC output terminals 28. These AC output terminals 28 are connected to an alternator 81.
5, as shown in FIG. 9, the bus bar 3 is a first part 31 constituting the first power conversion circuit 10 A, a second portion 32 of the second power conversion circuit 10 B is. A smoothing capacitor 4 is provided in each of the first portion 31 and the second portion 32. In addition, the first portion 31 is provided with the filter capacitor 5. In the present embodiment, an electrolytic capacitor is used as the smoothing capacitor 4. Also, a ceramic capacitor is used as the filter capacitor 5.
The first portion 31 and the second portion 32 are connected to each other. Further, FIG. 1, as shown in FIG. 2, the positive electrode bus bar 3 P, positive connection terminal 37 P are formed. The positive electrode connection terminal 37 P is connected to the positive electrode of the DC power supply 8. Similarly, as shown in FIG. 5, the negative bus bar 3 N, the negative electrode connecting terminal 37 N is formed. The negative electrode connection terminal 37 N is connected to the negative electrode of the DC power supply 8 and GND.
Further, as shown in FIG. 9, the power conversion device 1 includes a field circuit 71. The field circuit 71 is a circuit for passing a field current to the field winding 811 of the alternator 81 to generate a magnetic field. The magnetic field generated from the field winding 811 acts on a coil (not shown) in the alternator 81. The field circuit 71 comprises four MOSFETs 79. By turning on two MOSFETs 79 A and 79 D of these four MOSFETs 79, a field current is supplied to the field winding 811. The above-mentioned magnetic field is generated by this.
Further, as shown in FIG. 9, a control circuit 72 is formed on the circuit board 7. The control circuit 72 is a circuit for performing operation control of the switching element 20 and the field circuit 71. The field circuit 71 and control circuit 72, the positive bus bar 3 P, are connected to the board connecting portion 39 to be described later.
Further, as shown in FIG. 1 and FIG. 5, the power conversion device 1 of the present embodiment is provided with a case 6. Case 6 includes an outer wall portion 61 O, and the inner wall portion 61 I, and a mounting wall portion 62. The semiconductor module 2 is mounted on the mounting wall portion 62. Between the outer wall 61 O and the inner wall portion 61 I, annular accommodation space S is formed. In the housing space S, the switching element 20, the bus bar 3, the smoothing capacitor 4, the filter capacitor 5 and the like are housed. The housing space S is filled with a sealing member 69 (see FIGS. 7 and 8) made of epoxy resin or the like.
  As shown in FIGS. 1 and 2, the semiconductor module 2 includes a radiator 29 (fin) for radiating the heat generated from the switching element 20. The radiator 29 protrudes from the case 6. The radiator 29 is disposed on the side opposite to the side where the alternator 81 (see FIG. 10) is disposed.
  As shown in FIGS. 3 and 4, the filter capacitor 5 is disposed adjacent to the bus bar 3. The filter capacitor 5 is connected to the capacitor connection portion 36 of the bus bar 3. The filter capacitor 5 is disposed at a position adjacent to the portion 360 in the thickness direction (X direction) of the portion 360 of the bus bar 3 in which the capacitor connection portion 36 is formed.
  As shown in FIG. 5 and FIG. 6, the semiconductor module 2 includes a main body 21 incorporating the switching element 20, a DC input terminal 27 projecting from the main body 21, an AC output terminal 28, and a control terminal 26. Prepare. The AC output terminal 28 is connected to the alternator 81 as described above. The control terminal 26 is connected to the circuit board 7 (see FIGS. 7 and 8).
As shown in FIG. 6, the direct current input terminal 27 is connected to the module connection portion 35 of the bus bar 3. Among the positive bus bar 3 P, the portion between the connecting portions of the filter capacitor 5 and (capacitor connecting portion 36) and the module connector 35, the board connecting portion 39 is formed. As shown in FIG. 8, the board connection portion 39 is connected to the circuit board 7. Thus, drive power is supplied to the field circuit 71 and the control circuit 72 formed on the circuit board 7.
The operation and effect of the present embodiment will be described. In this embodiment, as shown in FIGS. 3 and 4, the filter capacitor 5 is disposed at a position adjacent to the pair of bus bars 3 (3 P , 3 N ).
Therefore, parasitic inductance L can be suppressed between the filter capacitor 5 and the bus bar 3 (for example, the wiring 51). Therefore, even for a noise current with a high frequency f, the impedance Z (= 2πfL) parasitic between the filter capacitor 5 and the bus bar 3 can be sufficiently reduced, and this noise current can easily flow to the filter capacitor 5. Therefore, it is easy to remove the noise current whose frequency f is high.
  Further, when the above configuration is adopted, noise current can be easily removed by the filter capacitor 5, and therefore, as the filter capacitor 5, one having a small electrostatic capacitance can be used. Therefore, a small size filter capacitor 5 can be used, and the power converter 1 can be easily miniaturized.
Further, in the present embodiment, the pair of bus bars 3 are disposed to face each other at a predetermined interval.
Therefore, the magnetic fields generated from the individual bus bars 3 can be canceled each other, and the inductance parasitic on the pair of bus bars 3 can be reduced. Therefore, a large inductance is less likely to be parasitic on a portion of the bus bar 3 that is present between the semiconductor module 2 and the filter capacitor 5, and the impedance Z at this portion can be reduced. Therefore, the noise current generated from the semiconductor module 2 can easily flow to the filter capacitor 5, and the noise current can be efficiently removed.
Moreover, as shown in FIG. 9, the power converter device 1 of this form is equipped with the circuit board 7 in which the field circuit 71 was formed. As shown in FIG. 6 and FIG. 8, the field circuit 71 is a connection portion (module connection portion 36) of the positive electrode bus bar 3 P with the filter capacitor 5 and a connection portion (module connection portion 35) Connected to the part between.
In this manner, the noise current generated from the field circuit 71 can be removed by the filter capacitor 5, the noise current can be prevented from leaking to the outside from the positive electrode connection terminal 37 P.
Further, a control circuit 72 for controlling the operation of the semiconductor module 2 is also formed on the circuit board 7. The control circuit 72 is connected to a portion of the positive electrode bus bar 3 P between the capacitor connection portion 36 and the module connection portion 35 as in the field circuit 71.
In this manner, the noise current generated from the control circuit 72, can be removed by the filter capacitor 5, the noise current can be prevented from leaking to the outside from the positive electrode connection terminal 37 P.
Further, as shown in FIG. 1 and FIG. 5, the power conversion device 1 of the present embodiment is provided with a case 6. The semiconductor module 2, the pair of bus bars 3 and the smoothing capacitor 4 are accommodated in the accommodation space S of the case 6. Further, the storage space S also accommodates a filter capacitor 5.
In this case, the case 6 can ensure waterproofness of the filter capacitor 5 and the like.
Further, as shown in FIGS. 7 and 8, in the present embodiment, the housing space S is filled with a sealing member 69.
Therefore, the waterproofness of the filter capacitor 5 and the like can be further enhanced by the sealing member 69. As described above, the power conversion device 1 of the present embodiment is attached to the on-vehicle alternator 81. Therefore, the power conversion device 1 is disposed in an environment susceptible to water. Therefore, the effect obtained by enhancing the waterproofness of the filter capacitor 5 and the like by the case 6 and the sealing member 69 is large.
  As described above, according to the present embodiment, it is possible to provide a power conversion device capable of reducing noise current more efficiently.
  In this embodiment, as shown in FIGS. 4 and 7, the filter capacitor 5 is disposed at a position adjacent to the bus bar 3 in the X direction, but the present invention is not limited to this. That is, as shown in FIG. 11, the filter capacitor 5 may be disposed at a position adjacent to the bus bar 3 in the Z direction (the alignment direction of the alternator 81 and the power conversion device 1: see FIG. 10).
  Further, as shown in FIG. 4, in the present embodiment, the filter capacitor 5 is directly connected to the bus bar 3, but the present invention is not limited to this. That is, as shown in FIG. 12, the filter capacitor 5 may be mounted on the capacitor substrate 59, and the connection pins 590 protruding from the capacitor substrate 59 may be connected to the bus bar 3. Further, although two filter capacitors 5 are connected in series in the example of FIG. 12, they may be connected in parallel, and only one filter capacitor 5 may be mounted on the capacitor substrate 59.
  In the following embodiments, among the reference numerals used in the drawings, the same reference numerals as those used in the first embodiment denote the same constituent elements as those in the first embodiment unless otherwise indicated.
Second Embodiment
The present embodiment is an example in which the number of filter capacitors 5 is changed. 13, as shown in FIG. 14, in this embodiment, as in Embodiment 1, are constituted with the first power conversion circuit 10 A and a second power conversion circuit 10 B. In this embodiment, as the filter capacitor 5, a second filter for removing a first filter capacitor 5 A for removing noise current generated from the first power conversion circuit 10 A, a noise current generated from the second power conversion circuit 10 B and a capacitor 5 B. These filter capacitors 5 A, 5 B is, as shown in FIG. 13, are respectively arranged at a position adjacent to the pair of bus bars 3.
The operation and effect of the present embodiment will be described. The power converter 1 of the present embodiment includes the two filter capacitors 5 A and 5 B , so noise current can be removed more efficiently.
The other configurations and effects are the same as those of the first embodiment.
(Embodiment 3)
The present embodiment is an example in which the arrangement position of the filter capacitor 5 is changed. As shown in FIG. 15, the power conversion device 1 of the present embodiment includes the case 6 as in the first embodiment. Case 6 is made of resin. In the present embodiment, the filter capacitor 5 is inserted into the wall portion 61 (inner wall portion 61 I ) of the case 6.
With the above configuration, the waterproof performance of the filter capacitor 5 can be further enhanced.
The other configurations and effects are the same as those of the first embodiment.
(Embodiment 4)
The present embodiment is an example in which the arrangement position of the filter capacitor 5 is changed. As shown in FIG. 16, in the present embodiment, the filter capacitor 5 is disposed outside the case 6. The filter capacitor 5 is disposed adjacent to the bus bar 3 as in the first embodiment. An inner wall portion 61 I of the case 6 is interposed between the filter capacitor 5 and the bus bar 3. Further, the filter capacitor 5 is disposed between the radiator 29 of the semiconductor module 2 and the smoothing capacitor 4.
The operation and effect of the present embodiment will be described. As described above, in the present embodiment, the filter capacitor 5 is disposed outside the case 6.
Therefore, when the filter capacitor 5 breaks down, it can be easily replaced.
Further, in the present embodiment, the filter capacitor 5 is disposed between the radiator 29 and the smoothing capacitor 4.
In this way, the space between the radiator 29 and the smoothing capacitor 4 can be effectively used, and the power converter 1 can be miniaturized.
The other configurations and effects are the same as those of the first embodiment.
DESCRIPTION OF SYMBOLS 1 Power converter 2 Semiconductor module 20 Switching element 3 P positive electrode bus-bar 3 N negative electrode bus-bar 3 bus-bar 4 smoothing capacitor 5 filter capacitor 8 DC power supply

Claims (9)

  1. A power conversion device (1) for converting DC power supplied from a DC power supply (8) into AC power,
    A semiconductor module (2) incorporating a switching element (20);
    A pair of bus bars (3) of a positive bus bar (3 P ) connecting the positive electrode of the DC power supply and the semiconductor module, and a negative bus bar (3 N ) connecting the negative electrode of the DC power supply and the semiconductor module )When,
    A smoothing capacitor (4) connected to the pair of bus bars for smoothing a DC voltage applied to the semiconductor module;
    And a filter capacitor (5) smaller in electrostatic capacitance than the smoothing capacitor, connected to the pair of bus bars, and removing noise current generated from the semiconductor module,
    The pair of bus bars are opposed to each other at a predetermined distance in the thickness direction of the bus bar,
    The filter capacitor has a shorter current path length to the semiconductor module than the smoothing capacitor.
    The power conversion device, wherein the filter capacitor is disposed at a position adjacent to the pair of bus bars.
  2.   The apparatus further comprises a field circuit (71) configured to drive an alternating current motor by the alternating current power and supplying a field current to a field winding (811) of the alternating current motor, the field circuit including the positive electrode The power conversion device according to claim 1, wherein among the bus bars, a portion between the connection portion with the filter capacitor and the connection portion with the semiconductor module is electrically connected.
  3.   The control circuit (72) for controlling the operation of the semiconductor module is further provided, wherein the control circuit is provided at a portion between the connection portion with the filter capacitor and the connection portion with the semiconductor module in the positive electrode bus bar. The power converter device according to claim 1 or 2, which is electrically connected.
  4.   The case (6) which accommodates the said semiconductor module, a pair of said bus bars, and the said smoothing capacitor is further provided, The said filter capacitor is inserted in the wall part (61) of this case. The power converter device according to one item.
  5.   The method according to any one of claims 1 to 3, further comprising a case for housing the semiconductor module, the pair of bus bars, and the smoothing capacitor, wherein the filter capacitor is housed in a housing space (S) of the case. Power converter according to claim 1.
  6.   The power conversion device according to claim 5, wherein the housing space is filled with a sealing member (69).
  7.   The power conversion according to any one of claims 1 to 3, further comprising: a case for housing the semiconductor module, the pair of bus bars, and the smoothing capacitor, wherein the filter capacitor is disposed outside the case. apparatus.
  8.   The said semiconductor module is provided with the heat sink (29) which thermally radiates the heat which generate | occur | produces from the said switching element, The said filter capacitor is distribute | arranged between the said heat sink and the said smoothing capacitor. The power converter according to any one of the preceding claims.
  9. By the switching element, the first power conversion circuit and (10 A) and at least two of the power conversion circuit (10) is configured between the second power converter (10 B), as the filter capacitor, the first power The first filter capacitor ( 5A ) for removing noise current generated from the conversion circuit, and the second filter capacitor ( 5B ) for removing noise current generated from the second power conversion circuit. The power converter device of any one of 8.
JP2017215668A 2017-11-08 2017-11-08 Power conversion equipment Pending JP2019088137A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2017215668A JP2019088137A (en) 2017-11-08 2017-11-08 Power conversion equipment

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Application Number Priority Date Filing Date Title
JP2017215668A JP2019088137A (en) 2017-11-08 2017-11-08 Power conversion equipment

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JP2019088137A true JP2019088137A (en) 2019-06-06

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JP2017215668A Pending JP2019088137A (en) 2017-11-08 2017-11-08 Power conversion equipment

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