JP5561248B2 - Power converter - Google Patents

Description

  The present invention relates to a power conversion device including a switching unit including a plurality of semiconductor elements and a capacitor module including a plurality of capacitor cells electrically connected to the switching unit.

  For example, there are power converters such as inverters and converters that are mounted on electric vehicles, hybrid vehicles, and the like and convert power between a DC power supply (battery) and an AC rotating electrical machine (motor generator). Such a power conversion device includes a switching unit composed of a plurality of semiconductor elements, and a capacitor module composed of a plurality of capacitor cells electrically connected to the switching unit. The capacitor module constitutes a smoothing capacitor for smoothing the voltage input to the switching unit.

  The capacitor module is formed by connecting a plurality of capacitor cells in parallel by at least a pair of bus bars, and the bus bars are connected to the switching unit. Here, if the wiring distance between each capacitor cell and the switching unit differs among the plurality of capacitor cells, a difference occurs in inductance in the current path of each capacitor cell. The high frequency component of the current tends to flow through a path with a smaller inductance.

  Here, in the power conversion device, a ripple current may flow into the capacitor module as the switching unit is turned on and off. Therefore, if there is a difference in the inductance of the current path of each capacitor cell, the current density varies among the plurality of capacitor cells, resulting in a difference in the amount of heat generated. As a result, there is a possibility that the heat generation of the specific capacitor cell is increased.

  In response to this problem, the arrangement and shape of the capacitor cells and bus bars are devised to suppress variations in the wiring distance from the switching unit and to suppress variations in the electrical resistance value among the plurality of capacitor cells. Thus, a means for suppressing variation in inductance has been proposed (Patent Document 1).

JP 2004-289955 A

  However, in the method described in Patent Document 1, since the inductance is adjusted by devising the arrangement and shape of the capacitor cell and the bus bar, the arrangement and shape of these members are restricted. As a result, there is a risk that the degree of freedom in designing the power conversion device is reduced.

  The present invention has been made in view of such a background, and power conversion capable of reducing variations in temperature rise among a plurality of capacitor cells while ensuring the degree of freedom in designing the arrangement and shape of capacitor cells and bus bars. The device is to be provided.

One aspect of the present invention is a power conversion device including a switching unit including a plurality of semiconductor elements and a capacitor module including a plurality of capacitor cells electrically connected to the switching unit.
The capacitor module has at least a pair of bus bars connected in parallel to the plurality of capacitor cells and connected to the switching unit,
Further, the capacitor module is provided with an adjustment member for adjusting the inductance of the capacitor cell in the vicinity of at least one of the plurality of capacitor cells.
The adjustment member is configured to adjust an inductance of the capacitor cell by affecting a magnetic flux generated due to a loop current flowing in the capacitor cell. 1).

  In the power conversion apparatus, the capacitor module is configured by disposing the adjusting member in proximity to at least one of the plurality of capacitor cells. Thereby, the inductance of each capacitor cell can be individually adjusted using the adjusting member. Therefore, the inductance variation among the plurality of capacitor cells can be easily performed using the adjusting member. As a result, it is possible to reduce the variation in ripple current flowing through each capacitor cell, and to reduce the variation in temperature rise among the plurality of capacitor cells.

  Further, since the adjustment of the inductance of the capacitor cell as described above can be performed by the arrangement of the adjustment member, it is not necessary to devise the shape and arrangement of the bus bar, the arrangement of the capacitor cell, etc. . Therefore, the degree of freedom in designing the arrangement and shape of the capacitor cell and the bus bar can be ensured.

  As described above, according to the above aspect, it is possible to provide a power converter that can reduce variations in temperature rise among a plurality of capacitor cells while ensuring the degree of freedom in designing the arrangement and shape of the capacitor cells and bus bars. be able to.

FIG. 3 is a perspective view of the capacitor module according to the first embodiment. FIG. 3 is a cross-sectional view of the capacitor module according to the first embodiment. The circuit diagram of the power converter device in Example 1. FIG. Explanatory drawing of the function of the adjustment member in Example 1. FIG. Sectional drawing of the capacitor module in Example 2. FIG. The circuit diagram of the test circuit which has arrange | positioned the adjustment member in an experiment example. The circuit diagram of the test circuit which has not arrange | positioned the adjustment member in an experiment example. The measured value of the electric current which flows into each capacitor | condenser cell in the test circuit which has arrange | positioned the adjustment member in an experiment example. Measured value of current flowing in each capacitor cell in a test circuit in which no adjustment member is arranged in the experimental example. The diagram which shows the inductance of each capacitor | condenser cell in an experiment example. Sectional drawing of the capacitor | condenser module in Example 3. FIG. FIG. 10 is a perspective view of a capacitor module according to a fourth embodiment. Explanatory drawing of the function of the adjustment member in Example 4. FIG. FIG. 10 is a perspective view of a capacitor module according to a fifth embodiment.

  In the present specification, the inductance of the capacitor cell means an inductance of a current path constituted by the capacitor cell and a bus bar connected to the capacitor cell. The loop current flowing in the capacitor cell means a current flowing in a current path constituted by the capacitor cell and a bus bar connected to the capacitor cell.

  Further, at least one of the adjusting members is a conductive adjusting member having conductivity, and a magnetic flux generated by a loop current flowing in the capacitor cell arranged in proximity is configured to penetrate the conductive adjusting member. (Claim 2). In this case, when the magnetic flux generated by the loop current flowing through the capacitor cell changes, an eddy current is generated in the conductive adjustment member in a direction that prevents the change in the magnetic flux. That is, when the magnetic flux generated by the loop current flowing through the capacitor cell increases, the eddy current is generated so as to generate a magnetic flux opposite to the magnetic flux. Thereby, the magnetic flux generated by the loop current and the magnetic flux generated by the eddy current cancel each other, and the inductance of the capacitor cell is reduced. This makes it easy for a ripple current to flow through the capacitor cell. In this way, it is possible to suppress variations in the ease of flow of ripple current among the plurality of capacitor cells, and to easily reduce variations in temperature rise.

  Further, the conductivity adjusting member can be disposed close to at least the capacitor cell having the longest wiring distance from the switching portion. In this case, the variation in inductance between the plurality of capacitor cells can be easily suppressed, and the variation in temperature rise between the plurality of capacitor cells can be reduced.

  In addition, the conductivity adjusting member is arranged in proximity to each of the plurality of capacitor cells, and the conductivity adjusting member arranged closer to the capacitor cell having a longer wiring distance from the switching unit. The coupling coefficient with the loop current flowing through the capacitor cell can be increased (claim 4). Here, the coupling coefficient indicates a ratio at which the magnetic flux generated by the loop current is linked to the conductive adjustment member. In this case, the eddy current is more likely to be formed in the conductive adjustment member disposed closer to the capacitor cell having a longer wiring distance from the switching unit. Therefore, the inductance of the capacitor cell that tends to increase the inductance when the conductivity adjusting member is not provided can be reduced by the conductivity adjusting member. As a result, it is possible to effectively reduce the inductance variation among the plurality of capacitor cells.

  Further, the conductivity adjusting member is a flat plate member, and a main surface thereof may be configured to be parallel to a path of the loop current flowing in the capacitor cell arranged in proximity. ). In this case, the eddy current flowing through the conductivity adjusting member is easily formed. Therefore, the inductance of the capacitor cell can be adjusted more effectively. The principal surface of the conductivity adjusting member being parallel to the path of the loop current includes substantially parallel, even if the main surface of the conductivity adjusting member is deviated from strict parallel as long as the above-described effects are sufficiently obtained. Good. The same applies hereinafter.

  Further, at least one of the adjusting members is a magnetic adjusting member having magnetism, and a magnetic flux generated by a loop current flowing in the capacitor cell arranged in proximity is formed in a part of the magnetic adjusting member. (Claim 6). In this case, it is possible to increase the inductance of the capacitor cell in which the magnetic adjustment member is disposed in proximity. That is, when the magnetic adjustment member is arranged as described above, the magnetic flux generated by the loop current flowing through the capacitor cell is increased. As a result, the inductance of the capacitor cell increases. Thereby, since the inductance of each capacitor cell can be easily adjusted, the variation in inductance among the plurality of capacitor cells can be easily reduced, and the variation in temperature rise can be easily reduced.

  In addition, it is preferable that the magnetic adjustment member is disposed close to at least the capacitor cell having the shortest wiring distance from the switching unit. In this case, the variation in inductance between the plurality of capacitor cells can be easily suppressed, and the variation in temperature rise between the plurality of capacitor cells can be reduced.

  In addition, at least a part of the magnetic adjustment member can be disposed inside a loop current flowing through the capacitor cell. In this case, the magnetic flux generated by the loop current is easily increased by the magnetic adjustment member. Therefore, the inductance of the capacitor cell can be adjusted more effectively.

Example 1
Examples of the power conversion device will be described with reference to FIGS.
As shown in FIG. 3, the power conversion device 1 of this example includes a switching unit 2 composed of a plurality of semiconductor elements and a capacitor module 3 composed of a plurality of capacitor cells 30 electrically connected to the switching unit 2. Yes.

As shown in FIGS. 1 and 2, the capacitor module 3 includes a pair of bus bars 41 and 42 that connect a plurality of capacitor cells 30 in parallel and are connected to the switching unit 2.
The capacitor module 3 is provided with an adjusting member 5 that adjusts the inductance of the capacitor cell 30 in the vicinity of at least one of the plurality of capacitor cells 30.

The adjustment member 5 is configured to adjust the inductance of the capacitor cell 30 by affecting the magnetic flux generated due to the loop current flowing through the capacitor cell 30.
In the present example, the adjusting member 5 is a conductive adjusting member 51 having conductivity made of copper or the like. Then, as shown in FIG. 4, the magnetic flux φ0 generated by the loop current I0 flowing through the capacitor cell 30 arranged in proximity is penetrated through the conductivity adjusting member 51.

  As shown in FIGS. 1 to 3, the conductive adjustment member 51 is disposed close to the capacitor cell 301 having the longest wiring distance from the switching unit 2. In this example, the capacitor module 3 includes three capacitor cells 30 (301, 302, 303) connected in parallel to each other by bus bars 41, 42. The three capacitor cells 30 have different wiring distances from the switching unit 2, the wiring distance between the capacitor cell 301 and the switching unit 2 is the longest, and between the capacitor cell 303 and the switching unit 2. The wiring distance is the shortest. The conductive adjustment member 51 is disposed close to the capacitor cell 301 having the longest wiring distance to the switching unit 2.

Each capacitor cell 30 is made of a film capacitor, and as shown in FIGS. 1 and 2, the three capacitor cells 30 are arranged in a line with the winding axis direction being parallel. A pair of electrodes 31, 32 are formed on both bottom surfaces of the substantially elliptical columnar shape in the capacitor cell 30, and bus bars 41, 42 are connected to the respective electrodes 31, 32.
As shown in FIG. 1, the bus bar 41 includes a main body plate portion 411 extending in the arrangement direction of the plurality of capacitor cells 30, and three terminal portions 412 protruding from the main body plate portion 411 in the width direction. The bus bar 41 is connected to the electrode 31 of the capacitor cell 30 at each terminal portion 412. The bus bar 41 is connected to the switching unit 2 at a bus bar terminal 414 arranged at one end of the main body plate 411 in the extending direction on the capacitor cell 303 side.

  The bus bar 42 includes a main body plate portion 421 extending in the arrangement direction of the plurality of capacitor cells 30, a standing plate portion 422 extending in the normal direction of the main body plate portion 421 and parallel to the extending direction of the main body plate portion 421, The terminal plate 422 includes three terminal portions 423 that are bent and extended at substantially right angles at the end opposite to the main body plate portion 421 side. The main body plate portion 421 of the bus bar 42 is disposed to face the main body plate portion 411 of the bus bar 41, the standing plate portion 422 of the bus bar 42 is disposed to face the side surfaces of the three capacitor cells 30, and the terminal portion 423 of the bus bar 42 is Are respectively connected to the electrodes 32 of the capacitor cell 30. The bus bar 42 is connected to the switching unit 2 at a bus bar terminal 424 arranged at one end of the main body plate 421 in the extending direction on the capacitor cell 303 side.

  Capacitor module 3 has a plurality of capacitor cells 30 and a pair of bus bars 41 and 42 arranged as described above, so that when current flows from switching unit 2 to each capacitor cell 30, the following is performed. A loop current path is formed. That is, the current flows from the electrode 32 to the capacitor cell 30 through the main plate 421 of the bus bar 42 connected to the switching unit 2, the standing plate 422, and the terminal 423. Then, a current flows from one electrode 32 to the other electrode 31 in the capacitor cell 30, and returns to the switching unit 2 from the terminal portion 412 of the other bus bar 41 through the main body plate portion 411. When a current flows through such a path, each capacitor cell 30 is formed with a loop-shaped current path substantially parallel to a plane orthogonal to the arrangement direction.

  The conductivity adjusting member 51 is a flat plate-like member, and its main surface is arranged so as to be substantially parallel to the path of the current flowing through the capacitor cells 301 arranged in proximity. That is, the conductivity adjusting member 51 is disposed so as to be orthogonal to the direction in which the capacitor cells 30 are arranged (the extending direction of the main body plate portions 411 and 421 of the bus bars 41 and 42).

  FIG. 3 is a circuit diagram showing a wiring state between the capacitor module 3 and the switching unit 2 in the power conversion device 1 of this example. In the figure, the inductance of each capacitor cell 30, that is, the inductance in the current path constituted between the switching unit 2 and each capacitor cell 30 by the capacitor cell 30 and the bus bars 41 and 42 connected thereto, Shown as L1, L2, and L3, respectively. These have a relationship of L1> L2> L3. The arrangement of the adjusting member 5 close to the capacitor cell 301 having the longest wiring distance from the switching unit 2 is coupled to the inductance component (L1) of the capacitor cell 301 as shown in FIG. This means that the inductance is reduced. Thereby, the dispersion | variation between the inductances L1, L2, and L3 is reduced.

  The power conversion device 1 can be an inverter or a converter that is mounted on, for example, an electric vehicle, a hybrid vehicle, or the like and used for power conversion between a DC power source (not shown) and an AC rotating electrical machine (not shown). . The capacitor module 3 can constitute a smoothing capacitor that smoothes the voltage of power supplied from the DC power supply to the switching unit 2.

Next, the function and effect of this example will be described.
In the power conversion device 1, the capacitor module 3 includes the adjusting member 5 disposed in the vicinity of at least one of the plurality of capacitor cells 30. Thereby, the inductance of each capacitor cell 30 can be individually adjusted using the adjustment member 5. Therefore, the inductance variation among the plurality of capacitor cells 30 can be easily performed using the adjustment member 5. As a result, it is possible to reduce the variation in the ripple current flowing through each capacitor cell 30, and to reduce the variation in temperature rise among the plurality of capacitor cells 30.

  Moreover, since the adjustment of the inductance of the capacitor cell 30 as described above can be performed by the arrangement of the adjustment member 5, it is not necessary to devise the shape and arrangement of the bus bars 41 and 42, the arrangement of the capacitor cell 30, etc. That restriction is especially eliminated. Therefore, it is possible to ensure the degree of freedom in designing the arrangement and shape of the capacitor cell 30 and the bus bars 41 and 42.

  Further, in this example, the adjusting member 5 is a conductive adjusting member 51 having conductivity, and as shown in FIG. 4, the magnetic flux φ0 generated by the loop current I0 flowing in the capacitor cell 30 arranged in the proximity is adjusted to be conductive. It is configured to penetrate the member 51. As a result, when the magnetic flux φ0 generated by the loop current I0 flowing through the capacitor cell 30 changes, an eddy current I1 is generated in the conductive adjustment member 51 in a direction that prevents the change of the magnetic flux φ0. That is, when the magnetic flux φ0 generated by the loop current I0 flowing through the capacitor cell 30 increases, the eddy current I1 is generated so that the magnetic flux φ1 opposite to the magnetic flux φ0 is generated. Thereby, the magnetic flux φ0 generated by the loop current I0 and the magnetic flux φ1 generated by the eddy current I1 cancel each other, and the inductance of the capacitor cell 30 decreases. As a result, a ripple current easily flows through the capacitor cell 30. In this way, variations in the ease of ripple current flow between the plurality of capacitor cells 30 can be suppressed, and variations in temperature rise can be easily reduced.

  In addition, the conductivity adjusting member 51 is disposed close to the capacitor cell having the longest wiring distance from the switching unit 2. Thereby, the dispersion | variation in the inductance between the several capacitor cells 30 can be suppressed easily, and the dispersion | variation in the temperature rise between the several capacitor cells 30 can be reduced.

  In addition, the conductivity adjusting member 51 is a flat plate member, and the main surface thereof is configured to be parallel to the path of the loop current I0 flowing through the capacitor cells 30 arranged in proximity. Thereby, the eddy current I1 flowing through the conductivity adjusting member 51 is easily formed. Therefore, the inductance of the capacitor cell 30 can be adjusted more effectively.

  As described above, according to this example, there is provided a power conversion device that can reduce variations in temperature rise among a plurality of capacitor cells while ensuring the degree of freedom in designing the arrangement and shape of capacitor cells and bus bars. be able to.

(Example 2)
In this example, as shown in FIG. 5, among the three capacitor cells 30, not only the capacitor cell 301 having the longest wiring distance from the switching unit 2 but also the capacitor cell having the second longest wiring distance from the switching unit 2. 302 is also an example in which the conductive adjustment member 51 is disposed in proximity.

  Similarly to the conductive adjustment member 511 arranged close to the capacitor cell 301, the conductive adjustment member 512 arranged close to the capacitor cell 302 is also a flat plate member, and a loop current path whose main surface flows to the capacitor cell 30. Are arranged in parallel with each other. The conductive adjustment member 512 disposed close to the capacitor cell 302 has a smaller area on the main surface (surface parallel to the loop current path) than the conductive adjustment member 511 disposed close to the capacitor cell 301. As a result, the coupling coefficient between the loop current of the capacitor cell 302 and the conductive adjustment member 512 adjacent thereto is determined by the coupling coefficient between the loop current of the capacitor cell 301 and the conductive adjustment member 511 adjacent thereto. Is also small.

  That is, in the power conversion device 1 of the present example, the coupling coefficient with the loop current flowing through the capacitor cell 30 is higher as the conductive adjustment member 51 is disposed closer to the capacitor cell 30 having a longer wiring distance from the switching unit 2. I try to get bigger.

In this example, as shown in FIG. 5, there is a difference in the lengths of the two conductive adjustment members 51 in the winding axis direction of the capacitor cell 30. In the direction orthogonal to the thickness direction, a difference may be provided in the lengths of the two conductivity adjusting members 51. Or you may provide a difference in the length of the two electroconductivity adjustment members 51 in both said two directions.
Others are the same as in the first embodiment.

In the case of this example, the eddy current is more likely to be formed in the conductive adjustment member 51 disposed closer to the capacitor cell 30 having a longer wiring distance from the switching unit. Therefore, the inductance can be reduced by the conductivity adjusting member 51 in the capacitor cell 30 in which the inductance tends to increase when the conductivity adjusting member 51 is not provided. As a result, the inductance variation among the plurality of capacitor cells 30 can be effectively reduced.
In addition, the same effects as those of the first embodiment are obtained.

  The above description is based on the assumption that the conductive adjustment member 512 is magnetically coupled only to the loop current of the capacitor cell 302 and not magnetically coupled to the loop current of the capacitor cell 301. . However, in the case of the arrangement shown in FIG. 5, the conductive adjustment member 512 is actually magnetically coupled to the loop current of the capacitor cell 301. However, even in this case, the capacitor cell 30 having a longer wiring distance from the switching unit 2 can increase the inductance reduction effect by the conductive adjustment member 51, and the size of the conductive adjustment member 51 and the capacitor cell 30. The fact that the inductance reduction effect can be adjusted by adjusting the distance is not different from the above description. This situation is the same as in Example 3 described later.

(Experimental example)
As shown in FIGS. 6 to 10, this example is an example in which an experiment for confirming the effect of the power conversion device 1 of Example 2 was performed.
That is, as shown in FIG. 6, in the power conversion device 1 of the second embodiment, the test circuit 10 in which the switching unit 2 is replaced with the AC power supply 101 is configured, and the current flowing through each capacitor cell 30 in the test circuit 10 is configured. Was measured. The AC power supply 101 is configured to apply a sine wave current having a peak current of 50 A and a frequency of 100 kHz to the capacitor module 3.

  Here, the inductance of the conductive adjustment member 51 is 10 nH, the inductance L1 of the capacitor cell 301 is 70 nH, the inductance L2 of the capacitor cell 302 is 60 nH, and the inductance L3 of the capacitor cell 303 is 50 nH. The inductance of the capacitor cell 30 (301, 302, 303) means the inductance in the current path that combines each capacitor cell 30 and the bus bars 41, 42.

In addition, the conductivity adjusting member 511 disposed in the vicinity of the capacitor cell 301 has a coupling coefficient of 0.5 with the loop current flowing in the capacitor cell 301, and the conductivity adjusting member 512 disposed in the vicinity of the capacitor cell 302 includes the capacitor cell 301. The coupling coefficient with the loop current flowing through 302 is 0.4.
Each capacitor cell 30 has a capacity of 100 μF.
In this example, the conductive adjustment member 511 is magnetically coupled only to the loop current flowing through the capacitor cell 301, and the conductive adjustment member 512 is magnetically coupled only to the loop current flowing through the capacitor cell 302. A simulation was performed on the premise.

For comparison, as shown in FIG. 7, a test circuit 90 in which the adjustment member 5 (conductive adjustment member 51) is not provided in the test circuit 10 was also prepared.
In these two test circuits 10 and 90, the current value of the current flowing through each capacitor cell 30 was measured. The results are shown in FIGS. In the figure, i1, i2, and i3 represent current values of currents flowing through the capacitor cells 301, 302, and 303, respectively.

In the test circuit 90 that does not use the adjustment member 5, as shown in FIG. 9, the current values i1, i2, and i3 of the currents flowing through the capacitor cells 301, 302, and 303 vary.
On the other hand, in the test circuit 10 using the adjustment member 5, as shown in FIG. 8, variations in the current values i 1, i 2, i 3 of the currents flowing through the capacitor cells 301, 302, 303 are small.

Based on the measurement results of the current values i1, i2, and i3 of the currents flowing through the capacitor cells 301, 302, and 303, the inductances L1 and L2 of the capacitor cells 301, 302, and 303 in a state where the adjustment member 5 is magnetically coupled. L3 was determined. The result is shown in FIG. As shown in the figure, when the adjustment member 5 is arranged as in the test circuit 10, there is almost no variation in inductance among the three capacitor cells 301, 302, and 303.
In FIG. 10, a line graph with M0 indicates the inductance of the capacitor cell 30 in the test circuit 90 where the adjustment member 5 is not disposed, and a line graph with M1 is in the test circuit 10 where the adjustment member 5 is disposed. The inductance of the capacitor cell 30 is shown.

  As described above, according to the present example, it can be seen that variation in inductance among the plurality of capacitor cells 30 in the capacitor module 3 can be reduced by appropriately arranging the adjusting member 5.

(Example 3)
In this example, as shown in FIG. 11, the conductive adjustment member 51 is disposed close to all three capacitor cells 30 in the capacitor module 3.
And the coupling coefficient between the conductive adjustment members 51 arranged closer to each other is increased as the loop current of the capacitor cell 30 having a longer wiring distance from the switching unit 2 is reached. That is, the coupling coefficient between the loop current of the capacitor cell 301 and the conductive adjustment member 511 adjacent thereto is equal to the coupling coefficient between the loop current of the capacitor cell 302 and the conductive adjustment member 512 adjacent thereto, and the capacitor cell 303. This is larger than the coupling coefficient between the loop current and the conductivity adjusting member 513 adjacent thereto. On the other hand, the coupling coefficient between the loop current of the capacitor cell 303 and the conductive adjustment member 513 adjacent thereto is equal to the coupling coefficient between the loop current of the capacitor cell 302 and the conductive adjustment member 512 adjacent thereto, and the capacitor cell 301. This is smaller than the coupling coefficient between the loop current and the conductive adjustment member 511 adjacent thereto.

  In this example, specifically, by changing the area of the main surface facing the capacitor cell 30 in the conductive adjustment member 51 and changing the distance between each conductive adjustment member 51 and each capacitor cell 30. The coupling coefficient between the loop current of the conductivity adjusting member 51 and the conductivity adjusting member 51 is adjusted. More specifically, the conductive adjustment member 51 disposed closer to the capacitor cell 30 having a longer wiring distance from the switching unit increases the area of the main surface facing the capacitor cell 30 and the distance from the capacitor cell 30. Is made smaller.

In adjusting the coupling coefficient between the loop current of the capacitor cell 30 and the conductivity adjusting member 51, either the area of the main surface of the conductivity adjusting member 51 or the distance to the capacitor cell 30 may be changed. it can.
Others are the same as in the first embodiment.

In the case of this example, the inductance of the plurality of capacitor cells 30 can be adjusted more precisely, and variations in the ripple current flowing through them can be further suppressed.
In addition, the same effects as those of the first embodiment are obtained.

(Example 4)
In this example, as shown in FIGS. 12 and 13, a magnetic adjustment member 52 having magnetism is used as the adjustment member 5.
The magnetic adjustment member 52 is arranged such that a magnetic flux φ0 generated by the loop current I0 flowing in the capacitor cell 30 arranged in proximity is formed in a part of the magnetic adjustment member 52. The magnetic adjustment member 52 is preferably made of a soft magnetic material, for example, iron.

In addition, the magnetic adjustment member 52 is disposed close to the capacitor cell 303 having the shortest wiring distance from the switching unit. Further, a part of the magnetic adjustment member 52 is disposed inside the loop current I 0 flowing through the capacitor cell 30. That is, the magnetic adjustment member 52 is disposed in a space surrounded by the standing plate portion 422 and the terminal portion 423 in the bus bar 42, the terminal portion 412 in the bus bar 41, and the capacitor cell 303. More specifically, the magnetic adjustment member 52 is disposed in the gap between the side surface of the capacitor cell 303 and the standing plate portion 422 of the bus bar 42.
In addition, the electroconductivity adjustment member 51 used in the power converter device 1 concerning Example 1, 2 is not arrange | positioned in the power converter device 1 of this example.
Others are the same as in the first embodiment.

  In the case of this example, it is possible to increase the inductance of the capacitor cell 303 in which the magnetic adjustment member 52 is disposed in proximity. That is, when the magnetic adjustment member 52 is arranged as described above, the magnetic flux φ0 generated by the loop current I0 flowing through the capacitor cell 303 increases. As a result, the inductance of the capacitor cell 303 is increased. Thereby, the dispersion | variation in the inductance between the some capacitor cells 30 can be reduced easily, and the dispersion | variation in a temperature rise can be reduced easily.

  Further, the magnetic adjustment member 52 is disposed close to the capacitor cell 303 having the shortest wiring distance from the switching unit 2. Therefore, the inductance variation among the plurality of capacitor cells 30 can be easily suppressed, and the variation in temperature rise between the plurality of capacitor cells 30 can be reduced.

Further, the magnetic adjustment member 52 is disposed at least partly inside the loop current I 0 that flows through the capacitor cell 30. Therefore, the magnetic adjustment member 52 can easily increase the magnetic flux φ0 generated by the loop current I0. Therefore, the inductance of the capacitor cell 303 can be adjusted more effectively.
In addition, the same effects as those of the first embodiment are obtained.

(Example 5)
As shown in FIG. 14, this example is an example of the power conversion device 1 that uses both the conductivity adjusting member 51 and the magnetic adjusting member 52 as the adjusting member 5.
That is, the conductive adjustment member 51 is disposed close to the capacitor cell 301 having the longest wiring distance from the switching unit, and the magnetic adjustment member 52 is disposed close to the capacitor cell 303 having the shortest wiring distance from the switching unit 2. The arrangement state of the conductive adjustment member 51 is the same as the arrangement state shown in the first embodiment, and the arrangement state of the magnetic adjustment member 52 is the same as the arrangement state shown in the fourth embodiment.

The conductive adjustment member 51 and the magnetic adjustment member 52 can be made of the same material. That is, for example, if the material has both conductivity and magnetism, such as iron, the conductivity adjusting member 51 and the magnetic adjusting member 52 can be formed of the same material.
Others are the same as in the first embodiment.

In the case of this example, the inductance of the capacitor cell 301 can be reduced by the conductive adjustment member 51, and the inductance of the capacitor cell 303 can be increased by the magnetic adjustment member 52. As a result, the inductance variation among the three capacitor cells 30 in the capacitor module 3 can be effectively reduced.
In addition, the same effects as those of the first embodiment are obtained.

In the above embodiment, the example in which the capacitor module 3 is configured by the three capacitor cells 30 has been shown. However, the number of the capacitor cells 30 is not particularly limited, and may be two or four or more. There may be.
Further, the capacitor cell is not limited to a film capacitor, and may be another type of capacitor.
The number of bus bars in the capacitor module is not limited to a pair, and may be two or more.

DESCRIPTION OF SYMBOLS 1 Power converter 2 Switching part 3 Capacitor module 30 Capacitor cell 41, 42 Bus bar 5 Adjustment member 51 Conductivity adjustment member 52 Magnetic adjustment member

Claims (8)

In a power conversion device including a switching unit composed of a plurality of semiconductor elements and a capacitor module composed of a plurality of capacitor cells electrically connected to the switching unit,
The capacitor module has at least a pair of bus bars connected in parallel to the plurality of capacitor cells and connected to the switching unit,
Further, the capacitor module is provided with an adjustment member for adjusting the inductance of the capacitor cell in the vicinity of at least one of the plurality of capacitor cells.
The power conversion device, wherein the adjustment member is configured to adjust an inductance of the capacitor cell by affecting a magnetic flux generated due to a loop current flowing in the capacitor cell.   2. The power conversion device according to claim 1, wherein at least one of the adjustment members is a conductive adjustment member having conductivity, and a magnetic flux generated by a loop current flowing in the capacitor cell arranged in proximity is generated by the conductivity. It is comprised so that an adjustment member may be penetrated, The power converter device characterized by the above-mentioned.   3. The power conversion device according to claim 2, wherein the conductivity adjusting member is disposed in proximity to at least the capacitor cell having the longest wiring distance from the switching unit.   4. The power conversion device according to claim 2, wherein the conductive adjustment member is disposed close to each of the plurality of capacitor cells, and the wiring distance from the switching unit is longer than the capacitor cell. The power conversion device according to claim 1, wherein a coupling coefficient with a loop current flowing through the capacitor cell is larger as the conductivity adjusting members arranged closer to each other.   5. The power conversion device according to claim 2, wherein the conductivity adjusting member is a flat plate member, and a main surface thereof is parallel to a path of the loop current flowing through the capacitor cells arranged in proximity. It is comprised so that the power converter device characterized by the above-mentioned.   6. The power conversion device according to claim 1, wherein at least one of the adjustment members is a magnetic adjustment member having magnetism, and is caused by a loop current flowing through the capacitor cells arranged in proximity. A power conversion device, wherein the generated magnetic flux is formed in a part of the magnetic adjustment member.   The power conversion device according to claim 6, wherein the magnetic adjustment member is arranged close to at least the capacitor cell having the shortest wiring distance from the switching unit.   8. The power conversion device according to claim 6, wherein at least a part of the magnetic adjustment member is disposed inside a loop current flowing through the capacitor cell. 9.

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