Film capacitor and power conversion device

Abstract

To provide a film capacitor which can reduce inductance.SOLUTION: A film capacitor C comprises a plurality of film capacitor elements, a first bus bar of first polarity, a second bus bar of second polarity, and a case 40, in which the first bus bar comprises a first input terminal 22 and a first pole output terminal 23, and the second bus bar comprises a second pole input terminal 32 and second pole output terminals 33. The second pole output terminals 33 are arranged on both sides of the first pole output terminal 23 in each of at least two phases, and the second pole output terminals 33 in different phases adjacent to each other become communized common terminals.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a film capacitor and a power conversion device including the film capacitor.

Background Art

[0002] Conventionally, a power conversion device that supplies three-phase AC power to a motor of an electric vehicle such as a hybrid vehicle or an electric vehicle is known. The power conversion device includes a DC / DC converter, an inverter, and a film capacitor. The DC / DC converter boosts and outputs the DC power supplied from the battery, and the inverter converts the boosted DC power output by the DC / DC converter into three-phase AC power and supplies it to the motor. The film capacitor is provided between the DC / DC converter and the inverter and functions as a smoothing capacitor.

[0003] As shown in FIG. 6(A), the output terminals of the film capacitor are composed of a U-phase terminal, a V-phase terminal, and a W-phase terminal of the cathode (N pole), and a U-phase terminal, a V-phase terminal, and a W-phase terminal of the anode (P pole). Terminals of the same phase are adjacent to each other, and the cathode terminals and the anode terminals are alternately arranged (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the film capacitor, the inductance of each terminal constituting the output terminal is determined by the width w of each terminal, and the larger the width w, the smaller the inductance. However, when the terminals are arranged close to each other, it is not possible to sufficiently secure the width w of each terminal, so there is a problem that the inductance increases.

[0006] On the other hand, when there is sufficient clearance between the terminals of the output terminal and the width of each terminal is increased, the distance between the through holes TH for fastening formed in each terminal (the distance between the through holes TH of different poles with the same phase) increases, and the inductance between each phase increases. For example, as shown in FIG. 6(B), when the width of each terminal is increased from w to w', since the distance between the through holes TH of different poles with the same phase increases from d to d', there is a problem that the inductance between each phase increases.

[0007] The present invention has been made in view of the above circumstances, and an object thereof is to provide a film capacitor capable of achieving low inductance and a power conversion device including the film capacitor.

Means for Solving the Problems

[0008] In order to solve the above problems, a film capacitor according to the present invention includes: a plurality of film capacitor elements having a first electrode and a second electrode; a first bus bar of a first polarity connected to the first electrode; a second bus bar of a second polarity connected to the second electrode; wherein the first bus bar includes a first pole main board, a first pole input terminal, a first pole first phase terminal for the first phase and a first pole second phase terminal for the second phase that constitute a first pole output terminal; and the second bus bar includes a second pole main board, a second pole input terminal, a second pole first phase terminal for the first phase and a second pole second phase terminal for the second phase that constitute a second pole output terminal; wherein the second pole first phase terminal includes a first terminal and a second terminal drawn out with the first pole first phase terminal interposed therebetween; and the second pole second phase terminal includes a third terminal; wherein the second terminal and the third terminal are a single shared first common terminal. is characterized in that

[0009] According to this configuration, since the second-pole first-phase terminal includes the first terminal and the second terminal drawn out with the first-pole first-phase terminal interposed therebetween, the width of the second-pole first-phase terminal can be increased without increasing the distance between the output portion (e.g., through hole for fastening) of the second-pole first-phase terminal and the output portion (e.g., through hole for fastening) of the first-pole first-phase terminal. As a result, inductance reduction can be achieved.

[0010] Furthermore, according to this configuration, since the second terminal and the third terminal are a single first common terminal that is shared, the terminal width can be made larger, and further inductance reduction can be achieved.

[0011] In the above film capacitor, the first bus bar includes a plurality of the first-pole output terminals, the second bus bar can be configured to include the same number of second-pole output terminals as the first-pole output terminals.

[0012] In order to solve the above problems, a power conversion device according to the present invention is a power conversion device that converts DC power supplied from a DC power source into AC power and supplies it to a load, a DC / DC converter that boosts the DC power and outputs boosted DC power, a film capacitor according to the present invention that smoothes the boosted DC power and outputs DC power for at least two phases, an inverter that generates at least two-phase AC power based on the DC power for at least two phases, and is characterized by including the above.

Effects of the Invention

[0013] According to the present invention, it is possible to provide a film capacitor capable of achieving inductance reduction and a power conversion device including the film capacitor.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0015] Hereinafter, embodiments of a film capacitor and a power conversion device according to the present invention will be described with reference to the accompanying drawings. The front-rear direction X, left-right direction Y, and up-down direction Z indicated by the arrows in the drawings are linear directions orthogonal to each other.

[0016] FIG. 1 shows a power conversion device 1 according to an embodiment of the present invention. The power conversion device 1 includes a DC / DC converter A, inverters B1 and B2, a film capacitor C according to an embodiment of the present invention, and a control circuit D.

[0017] The power conversion device 1 is mounted on an electric vehicle such as a hybrid vehicle or an electric vehicle, for example, and converts DC power supplied from a battery 2 (corresponding to the "DC power source" of the present invention) into AC power and supplies it to motors 3 and 4 (corresponding to the "load" of the present invention).

[0018] The DC / DC converter A boosts the DC power input from the battery 2 under the control of the control circuit D, and outputs the boosted DC power to the film capacitor C. The DC / DC converter A can be composed of, for example, an isolation transformer, a primary side switching circuit, and a secondary side rectifying and smoothing circuit.

[0019] The inverter B1 converts the three-phase DC power input from the film capacitor C into three-phase AC power under the control of the control circuit D, and outputs the three-phase AC power to the motor 3. Similarly, the inverter B2 converts the three-phase DC power input from the film capacitor C into three-phase AC power under the control of the control circuit D, and outputs the three-phase AC power to the motor 4. The inverters B1 and B2 include a U-phase switch circuit that generates U-phase AC power, a V-phase switch circuit that generates V-phase AC power, and a W-phase switch circuit that generates W-phase AC power. Each switch circuit can be composed of, for example, switching elements connected in series.

[0020] In this embodiment, the inverters B1 and B2 include input terminals corresponding to the output terminals of the film capacitor C. Specifically, each phase switch circuit of the inverters B1 and B2 includes an N input terminal, a first P input terminal, and a second P input terminal. For example, the first P input terminal and the second P input terminal are connected to one end of the switch circuit, and the N input terminal is connected to the other end of the switch circuit.

[0021] As described above, the control circuit D controls the DC / DC converter A and the inverters B1 and B2. The control circuit D can be composed of an analog control circuit, a digital control circuit including a microcontroller or the like, or a circuit combining both.

[0022] The film capacitor C is provided between the DC / DC converter A and the inverters B1 and B2 and functions as a smoothing capacitor. FIG. 2 shows a perspective view of the film capacitor C, and FIG. 3 shows an exploded perspective view of the film capacitor C.

[0023] The film capacitor C includes a capacitor element portion 10, an N bus bar 20 corresponding to the "first bus bar of the first polarity" of the present invention, a P bus bar 30 corresponding to the "second bus bar of the second polarity" of the present invention, a case 40, an insulating portion 50, and a sealing resin 60. In FIG. 3, the sealing resin 60 is omitted.

[0024] The capacitor element unit 10 includes eight film capacitor elements 11 (corresponding to the "film capacitor element" of the present invention) that function as smoothing capacitors.

[0025] The film capacitor element 11 is formed by winding a pair of metallized films with metal films (cathode and anode) as internal electrodes formed on the surface of a dielectric film, and forming metallicon parts as external electrodes at both winding ends. One metallicon part (corresponding to the "first electrode" of the present invention) is connected to the internal electrode (cathode) of one metallized film, and the other metallicon part (corresponding to the "second electrode" of the present invention) is connected to the internal electrode (anode) of the other metallized film. The film capacitor element 11 is arranged in the case 40 such that the first electrode is on the lower side and the second electrode is on the upper side.

[0026] The N bus bar 20 is an electrode terminal component formed by processing a metal plate and is a bus bar for the cathode. The N bus bar 20 includes an N main board 21 corresponding to the "first pole main board" of the present invention, an N input terminal 22 corresponding to the "first pole input terminal" of the present invention, and an N output terminal 23 corresponding to the "first pole output terminal" of the present invention.

[0027] The N main board 21 is housed in the case 40 and is connected to the first electrode on the lower side of the film capacitor element 11. The N input terminal 22 is drawn out from the front end of the N main board 21 and exposed on the front surface of the case 40, and is connected to the cathode output terminal of the DC / DC converter A. The N output terminals 23 are drawn out of the case 40 from the left and right ends of the N main board 21. Details of the N output terminals 23 will be described later.

[0028] The P bus bar 30 is an electrode terminal component formed by processing a metal plate and is a bus bar for the anode. The P bus bar 30 includes a P main board 31 corresponding to the "second pole main board" of the present invention, a P input terminal 32 corresponding to the "second pole input terminal" of the present invention, and a P output terminal 33 corresponding to the "second pole output terminal" of the present invention.

[0029] The P main board 31 is housed inside the case 40 and is connected to the second electrode on the upper side of the film capacitor element 11. The P input terminal 32 is drawn out from the front end of the P main board 31 and exposed on the front surface of the case 40 so as to be adjacent to the N input terminal 22, and is connected to the output terminal for the anode of the DC / DC converter A. The P output terminals 33 are drawn out from the left end and the right end of the P main board 31 to the outside of the case 40. Details of the P output terminals 33 will be described later.

[0030] The case 40 is a housing formed of an insulating resin and includes a bottom portion 41 and a peripheral wall portion 42. The bottom portion 41 and the peripheral wall portion 42 are integrally formed of the same insulating resin.

[0031] The bottom portion 41 is provided so as to be located below the N main board 21 of the N bus bar 20, and the peripheral wall portion 42 is provided so as to surround the sides (front, rear, left, right) of the N main board 21. That is, the bottom portion 41 and the peripheral wall portion 42 form a storage space for housing the N main board 21 of the N bus bar 20, the capacitor element portion 10, and the P main board 31 of the P bus bar 30.

[0032] The insulating portion 50 is provided to prevent a short circuit between the N bus bar 20 and the P bus bar 30. The insulating portion 50 includes a first insulating member 51, a second insulating member 52, and a third insulating member 53. The first insulating member 51 is disposed between the front end portion of the N main board 21 and the front end portion of the P main board 31. The second insulating member 52 is disposed between the left end portion of the N main board 21 and the left end portion of the P main board 31. The third insulating member 53 is disposed between the right end portion of the N main board 21 and the right end portion of the P main board 31.

[0033] The encapsulating resin 60 is a resin for protecting the capacitor element portion 10 housed in the storage space inside the case 40. The encapsulating resin 60 is, for example, a potting resin such as an epoxy resin, which is filled into the case 40 by a dispenser in a predetermined amount and then cured.

[0034] Fig. 4(A) shows the N output terminals 23 on the left side of the N bus bar 20, and Fig. 4(B) shows the P output terminals 33 on the left side of the P bus bar 30. Note that the N output terminals 23 on the right side of the N bus bar 20 have the same configuration as the N output terminals 23 on the left side, and the P output terminals 33 on the right side of the P bus bar 30 have the same configuration as the P output terminals 33 on the left side.

[0035] The N output terminals 23 include the N output terminal 23U for the U phase corresponding to the "first-pole first-phase terminal" of the present invention, the N output terminal 23V for the V phase corresponding to the "first-pole second-phase terminal" of the present invention, and the N output terminal 23W for the W phase corresponding to the "first-pole third-phase terminal" of the present invention. The N output terminals 23U, 23V, and 23W each have a predetermined width w1, w2, and w3. In this embodiment, w1 = w2 = w3.

[0036] Through holes TH (round holes in this embodiment) for fastening to the N input terminals in each phase of the inverter B1 are formed as output portions in the N output terminals 23U, 23V, and 23W. The N output terminal 23U is connected to the N input terminal of the U-phase switch circuit of the inverter B1. The N output terminal 23V is connected to the N input terminal of the V-phase switch circuit of the inverter B1. The N output terminal 23W is connected to the N input terminal of the W-phase switch circuit of the inverter B1.

[0037] The P output terminals 33 include the P output terminals 33U, 33U' for the U phase corresponding to the "second-pole first-phase terminal (first terminal, second terminal)" of the present invention, the P output terminals 33V, 33V' for the V phase corresponding to the "second-pole second-phase terminal (third terminal, fourth terminal)" of the present invention, and the P output terminals 33W, 33W' for the W phase corresponding to the "second-pole third-phase terminal (fifth terminal, sixth terminal)" of the present invention. However, the P output terminal 33U' and the P output terminal 33V are a single shared first common terminal 33UV, and the P output terminal 33V' and the P output terminal 33W are a single shared second common terminal 33VW.

[0038] The P output terminal 33U and the P output terminal 33W' each have a predetermined width w4 and w5. In this embodiment, w4 = w5, and w4 (= w5) is smaller than w1 (= w2 = w3).

[0039] The first common terminal 33UV and the second common terminal 33VW each have a predetermined width w6, w7. In the present embodiment, w6 = w7. w6 is larger than twice the value of the width w4 of the P output terminal 33U. w7 is larger than twice the value of the width w5 of the P output terminal 33W'.

[0040] Through holes TH (round holes in the present embodiment) for fastening to the P input terminals in each phase of the inverter B1 are formed as output portions in the P output terminal 33U, the first common terminal 33UV, the second common terminal 33VW, and the P output terminal 33W'. Two through holes TH are formed in each of the first common terminal 33UV and the second common terminal 33VW.

[0041] The P output terminal 33U is connected to the first P input terminal of the U-phase switch circuit of the inverter B1. The first common terminal 33UV is connected to the second P input terminal of the U-phase switch circuit of the inverter B1 on the P output terminal 33U side and is connected to the first P input terminal of the V-phase switch circuit of the inverter B1 on the second common terminal 33VW side. The second common terminal 33VW is connected to the second P input terminal of the V-phase switch circuit of the inverter B1 on the first common terminal 33UV side and is connected to the first P input terminal of the W-phase switch circuit of the inverter B1 on the P output terminal 33W' side. The P output terminal 33W' is connected to the second P input terminal of the W-phase switch circuit of the inverter B1.

[0042] As shown in FIG. 5, when the distance between the through-hole TH of the P output terminal 33U and the through-hole TH of the N output terminal 23U is d1, and the distance between the through-hole TH of the N output terminal 23U and the through-hole TH for the U-phase of the first common terminal 33UV is d1', then d1 = d1'. When the distance between the through-hole TH for the V-phase of the first common terminal 33UV and the through-hole TH of the N output terminal 23V is d2, and the distance between the through-hole TH of the N output terminal 23V and the through-hole TH for the V-phase of the second common terminal 33VW is d2', then d2 = d2'. When the distance between the through-hole TH for the W-phase of the second common terminal 33VW and the through-hole TH of the N output terminal 23W is d3, and the distance between the through-hole TH of the N output terminal 23W and the through-hole TH of the P output terminal 33W' is d3', then d3 = d3'.

[0043] In other words, through-holes TH for the U-phase and the V-phase are formed in the first common terminal 33UV such that d1 = d1' and d2 = d2'. Similarly, through-holes TH for the V-phase and the W-phase are formed in the second common terminal 33VW such that d2 = d2' and d3 = d3'.

[0044] In the film capacitor C according to the present embodiment, since the P output terminals 33 (33U, 33U', 33V, 33V', 33W, 33W') are arranged on both sides of the N output terminals 23 (23U, 23V, 23W) in each phase, the terminal width of the P output terminal 33 can be increased without increasing the distance between the output portions (between the through-holes TH) of different polarities in each phase. As a result, the inductance can be reduced.

[0045] Furthermore, in the film capacitor C according to the present embodiment, since the P output terminal 33U' and the P output terminal 33V are a single first common terminal 33UV that is common, and the P output terminal 33V' and the P output terminal 33W are a single second common terminal 33VW that is common, the terminal width of the P output terminal 33 can be made larger. As a result, further reduction in inductance can be achieved.

[0046] Moreover, by using the first common terminal 33UV, the P output terminal 33U' and the P output terminal 33V are necessarily located on the same plane. Therefore, compared with the case where the P output terminal 33U' and the P output terminal 33V are provided separately, it becomes easier to determine the dimensions of the terminals (for example, adjust the height of the terminals, etc.), and the complication of the assembly jig can be suppressed. The same effect also occurs for the second common terminal 33VW.

[0047] [Modification Example] As described above, the embodiments of the film capacitor and the power conversion device according to the present invention have been described. However, the present invention is not limited to the above embodiments.

[0048] The film capacitor according to the present invention includes a plurality of film capacitor elements, a first bus bar of a first polarity, and a second bus bar of a second polarity. The first bus bar includes a first main board of the first polarity, a first input terminal of the first polarity, and at least a first output terminal for two phases. The second bus bar includes a second main board of the second polarity, a second input terminal of the second polarity, and at least a second output terminal for two phases. And in each of at least two phases, if the second output terminals are arranged on both sides of the first output terminal and the second output terminals of adjacent different phases become common terminals, the configuration can be changed as appropriate.

[0049] The film capacitor according to the present invention may be a so-called resinless film capacitor without the encapsulating resin 60. Further, the film capacitor according to the present invention may be a so-called case-less film capacitor in which the capacitor element portion 10, the N main board 21 of the N bus bar 20, and the P main board 31 of the P bus bar 30 are coated with an exterior resin.

[0050] In the above embodiment, it corresponds to the three phases of U, V, and W. However, the film capacitor according to the present invention may correspond to two phases or may correspond to four or more phases.

[0051] In the above-described embodiment, P output terminals 33 (33U, 33U’, 33V, 33V’, 33W, 33W’) are arranged on both sides of the N output terminals 23 (23U, 23V, 23W) in each phase. However, the N output terminals 23 may be arranged on both sides of the P output terminals 33 in each phase. In that case, instead of the P bus bar 30, the N bus bar 20 is configured to include a first common terminal and a second common terminal.

[0052] The power conversion device according to the present invention is a power conversion device that converts DC power supplied from a DC power source into AC power and supplies it to a load. If it includes a DC / DC converter that boosts DC power to output boosted DC power, a film capacitor of the present invention that smoothes the boosted DC power to output DC power for at least two phases, and an inverter that generates AC power for at least two phases based on the DC power for at least two phases, the configuration can be changed as appropriate.

Explanation of Signs

[0053] A DC / DC converter B1, B2 Inverters C Film capacitor D Control circuit 1 Power conversion device 2 Battery 3, 4 Motors 10 Capacitor element section 11 Film capacitor element 20 N bus bar 21 N main board 22 N input terminal 23 N output terminal 30 P bus bar 31 P main board 32 P input terminal 33 P output terminal 33UV First common terminal 33VW Second common terminal 40 Case 41 Bottom 42 Peripheral wall section 50 Insulating section 51 First insulating member 52 Second insulating member 53 Third insulating member 60 Encapsulating resin

Claims

1. a plurality of film capacitor elements each having a first electrode and a second electrode; A first bus bar having a first polarity connected to the first electrode; a second bus bar having a second polarity connected to the second electrode; Case and A film capacitor comprising: the first bus bar includes a first pole first phase terminal for a first phase and a first pole second phase terminal for a second phase, which constitute a first pole main plate, a first pole input terminal, and a first pole output terminal; Equipped with the second bus bar includes a second pole first phase terminal for the first phase and a second pole second phase terminal for the second phase, which constitute a second pole main plate, a second pole input terminal, and a second pole output terminal; Equipped with the second-pole first-phase terminal includes a first terminal and a second terminal that are drawn out across the first-pole first-phase terminal, the second pole second phase terminal includes a third terminal; the second terminal and the third terminal are common to each other to form a single first common terminal, the case accommodates the film capacitor element, the first electrode main plate, and the second electrode main plate; The first pole output terminals extend symmetrically from the left end and the right end of the first pole main plate and are drawn out to the outside of the case, The second pole output terminals extend symmetrically from the left and right ends of the second pole main plate and are drawn out to the outside of the case. A film capacitor characterized by:

2. The first bus bar includes a plurality of the first pole output terminals, The second bus bar includes the second pole output terminals in the same number as the first pole output terminals.

2. The film capacitor according to claim 1 .

3. A power conversion device that converts DC power supplied from a DC power source into AC power and supplies the AC power to a load, a DC / DC converter that boosts the DC power and outputs boosted DC power; a film capacitor according to claim 1 or 2, which smoothes the boosted DC power and outputs at least two-phase DC power; an inverter that generates the at least two-phase AC power based on the at least two-phase DC power; A power conversion device comprising:

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