Power converter

Abstract

To provide a power conversion device with a smaller size. [Solution] The power conversion device comprises a semiconductor switching element, a smoothing capacitor having a plurality of capacitor elements 400, and a conductive busbar 420 connecting the semiconductor switching element and the smoothing capacitor. The busbar 420 is provided with a hole 421h. Furthermore, the power conversion device comprises a magnetic opposing member 500 positioned opposite at least a portion of the busbar 420. The hole 421h is provided at least at a position where the opposing member 500 faces each other.

Description

Technical Field

[0001] The present disclosure relates to a power conversion device.

Background Art

[0002] As disclosed in Patent Document 1, there is a power conversion device including a semiconductor switching element and a capacitor.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, a configuration in which a semiconductor switching element and a capacitor are connected by a bus bar is conceivable for a power conversion device. In this case, depending on the positional relationship between the semiconductor switching element and the capacitor, there may be portions where the ease of current flow is different in the bus bar. Therefore, in the power conversion device, the current distribution in the capacitor may vary.

[0005] One object to be disclosed is to provide a power conversion device capable of controlling the current distribution in a capacitor.

Means for Solving the Problems

[0006] The power conversion device disclosed herein includes semiconductor switching elements (21 to 26), a capacitor (42), conductive bus bars (410, 420, 4201 to 4209) connecting the semiconductor switching elements and the capacitor, and a magnetic opposing member (500) disposed opposite to at least a part of the bus bar.

[0007] According to the power conversion device disclosed herein, current is less likely to flow in the area where opposing members are positioned opposite each other in the busbar. Therefore, the power conversion device can control the current distribution in the capacitor depending on the position of the opposing members relative to the busbar.

[0008] The various embodiments disclosed in this specification employ different technical means to achieve their respective objectives. The claims and the reference numerals in parentheses in this section are intended to illustrate an example of correspondence with parts of the embodiments described later, and are not intended to limit the technical scope. The objectives, features, and effects disclosed in this specification will become clearer by referring to the subsequent detailed description and the accompanying drawings. [Brief explanation of the drawing]

[0009] [Figure 1] This is a circuit diagram showing the general configuration of a power conversion device. [Figure 2] This is a perspective view showing the schematic configuration of a capacitor device. [Figure 3] This is a plan view from the direction of arrow III in Figure 2. [Figure 4] This is a disassembled perspective view of a capacitor device. [Figure 5] This is a plan view showing the positional relationship between the busbar and the opposing member. [Figure 6] This is a cross-sectional view along the line VI-VI in Figure 5. [Figure 7] This is a plan view showing the positional relationship between the smoothing capacitor, the busbar, and the opposing component. [Figure 8] This is an equivalent circuit diagram between a smoothing capacitor and a semiconductor switching element. [Figure 9] This is an equivalent circuit diagram in a comparative example. [Figure 10] This is a plan view showing the schematic configuration of the power conversion device of Modified Example 1. [Figure 11] This is a plan view showing the schematic configuration of the power conversion device of modified example 2. [Figure 12] This is a plan view showing the schematic configuration of the power conversion device of modified example 3. [Figure 13] It is a plan view showing a schematic configuration of the power conversion device of Modification 4. [Figure 14] It is a plan view showing a schematic configuration of the power conversion device of Modification 5. [Figure 15] It is a plan view showing a schematic configuration of the power conversion device of Modification 6. [Figure 16] It is a plan view showing a schematic configuration of the power conversion device of Modification 7. [Figure 17] It is a cross-sectional view taken along line XVII-XVII of FIG. 16. [Figure 18] It is a plan view showing a schematic configuration of the power conversion device of Modification 8. [Figure 19] It is a plan view showing a schematic configuration of the power conversion device of Modification 9.

Embodiments for Carrying Out the Invention

[0010] Hereinafter, a plurality of embodiments for implementing the present disclosure will be described while referring to the drawings. In each embodiment, parts corresponding to those described in the preceding embodiment may be given the same reference numerals and redundant descriptions may be omitted. In each embodiment, when only a part of the configuration is described, other parts of the configuration can be referred to and applied to other embodiments described previously. In the following, three mutually orthogonal directions are shown as the X direction, the Y direction, and the Z direction.

[0011] (Embodiment) As shown in FIG. 1, the power conversion device 100 includes a boost converter circuit 10 and an inverter circuit 20. Further, the power conversion device 100 includes a filter capacitor 41 and a smoothing capacitor 42. Furthermore, the power conversion device 100 includes low voltage lines 31, 32, high voltage lines 33, 34, and each phase output lines 35 to 37 as wiring parts. Note that the power conversion device 100 is merely an example. For example, the power conversion device 100 may not include the boost converter circuit 10. Also, the power conversion device 100 may not include the inverter circuit 20 and the smoothing capacitor 42.

[0012] The low-voltage lines 31 and 32 are power wiring mainly located upstream of the boost converter circuit 10. The low-voltage P line 31 is connected to the positive terminal of the battery 200 and the boost converter circuit 10. The low-voltage N line 32 is connected to the negative terminal of the battery 200 and the boost converter circuit 10.

[0013] The high-voltage lines 33 and 34 are power lines mainly located downstream of the boost converter circuit 10. The high-voltage P line 33 is connected to the high-potential side of the boost converter circuit 10. The high-voltage N line 34 is connected to the low-potential side of the boost converter circuit 10.

[0014] Each phase output line 35-37 is an output wiring provided between the inverter circuit 20 and the motor 300. The U-phase output line 35 is connected to the connection point of the U-phase upper arm element 21 and the U-phase lower arm element 22, which will be described later, and to the U-phase coil. The V-phase output line 36 is connected to the connection point of the V-phase upper arm element 23 and the V-phase lower arm element 24, which will be described later, and to the V-phase coil. The W-phase output line 37 is connected to the connection point of the W-phase upper arm element 25 and the W-phase lower arm element 26, which will be described later, and to the W-phase coil.

[0015] The boost converter circuit 10 comprises an upper arm element 11, a lower arm element 12, and a reactor 13. In this embodiment, semiconductor switching elements are used as the upper arm element 11 and the lower arm element 12. In this embodiment, an IGBT is used as an example of a semiconductor switching element. IGBT is an abbreviation for Insulated Gate Bipolar Transistor. However, other semiconductor switching elements such as MOSFETs can also be used.

[0016] The upper arm element 11 and the lower arm element 12 are connected in series between the high-voltage P line 33 and the high-voltage N line 34. The collector electrode of the upper arm element 11 is connected to the high-voltage P line 33. The emitter electrode of the lower arm element 12 is connected to the high-voltage N line 34 (low-voltage N line 32).

[0017] The emitter electrode of the upper arm element 11 is connected to the collector electrode of the lower arm element 12. The point where the emitter electrode of the upper arm element 11 and the collector electrode of the lower arm element 12 are connected corresponds to the connection point between the upper arm element 11 and the lower arm element 12. The connection point between the upper arm element 11 and the lower arm element 12 is connected to the positive electrode of the battery 200 via the reactor 13 and the low-voltage P line 31.

[0018] The inverter circuit 20 includes a U-phase up / down arm circuit 20u, a V-phase up / down arm circuit 20v, and a W-phase up / down arm circuit 20w. The U-phase up / down arm circuit 20u includes a U-phase up arm element 21 and a U-phase down arm element 22. The V-phase up / down arm circuit 20v includes a V-phase up arm element 23 and a V-phase down arm element 24. The W-phase up / down arm circuit 20w includes a W-phase up arm element 25 and a W-phase down arm element 26.

[0019] Each phase arm element 21-26 is a semiconductor switching element. In this embodiment, IBGTs are used as an example of each phase arm element 21-26. However, each phase arm element 21-26 can also be a MOSFET or the like. Each phase arm element 21-26 can also be considered as a circuit component. Furthermore, in this disclosure, the phase arm elements 21-26 are sometimes collectively referred to as a semiconductor switching element. In addition, for convenience, in this disclosure, the inverter circuit 20 may also be considered as a semiconductor switching element.

[0020] The U-phase upper arm element 21 and the U-phase lower arm element 22 are connected in series between the high-voltage P line 33 and the high-voltage N line 34. The collector electrode of the U-phase upper arm element 21 is connected to the high-voltage P line 33. The emitter electrode of the U-phase lower arm element 22 is connected to the high-voltage N line 34.

[0021] The emitter electrode of the U-phase upper arm element 21 is connected to the collector electrode of the U-phase lower arm element 22. The point where the emitter electrode of the U-phase upper arm element 21 and the collector electrode of the U-phase lower arm element 22 are connected corresponds to the connection point between the U-phase upper arm element 21 and the U-phase lower arm element 22. The connection point between the U-phase upper arm element 21 and the U-phase lower arm element 22 is connected to the U-phase output line 35. The same applies to the V-phase upper and lower arm circuit 20V and the W-phase upper and lower arm circuit 20W.

[0022] The filter capacitor 41 is connected to the low-voltage P line 31 and the low-voltage N line 32. The smoothing capacitor 42 is connected to the high-voltage P line 33 and the high-voltage N line 34. The smoothing capacitor 42 is electrically connected to the reactor 13 via arm elements 11, 12, etc. In other words, the power converter 100 is equipped with a filter capacitor 41 and a smoothing capacitor 42 as capacitors.

[0023] <Smoothing Capacitor> Here, the smoothing capacitor 42 will be explained using Figures 2, 3, and 4. As shown in Figures 2, 3, and 4, the smoothing capacitor 42 comprises four capacitor elements 400. The four capacitor elements 400 are arranged in a line in the X direction. The four capacitor elements 400 are connected in parallel (Figure 8). However, in this embodiment, any smoothing capacitor 42 comprising multiple capacitor elements 400 can be used. The smoothing capacitor 42 corresponds to a capacitor.

[0024] Each capacitor element 400 is equipped with a first electrode 401 and a second electrode 402. The first electrode 401 is provided on one end of the capacitor element 400 in its thickness direction, and the second electrode 402 is provided on the other end. The first electrode 401 and the second electrode 402 are provided along the XY plane. The four capacitor elements 400 are arranged such that each first electrode 401 faces the same direction. For example, the first electrodes 401 of the four capacitor elements 400 are in the same position in the Y direction. Also, the second electrodes 402 of the four capacitor elements 400 are in the same position in the Y direction.

[0025] Furthermore, the thickness of the capacitor element 400 can also be said to be the length of the capacitor element 400 in the Z direction. The XY plane is a virtual plane defined by the X-axis along the X direction and the Y-axis along the Y direction.

[0026] The first electrode 401 is connected to the N busbar 410. The first electrode 401 and the N busbar 410 are connected by a conductive connecting member, such as solder. The second electrode 402 is connected to the P busbar 420. The second electrode 402 and the P busbar 420 are connected by a conductive connecting member, such as solder.

[0027] The capacitor element 400 is housed in a case primarily made of resin, with busbars 410 and 420 connected to it. Alternatively, the capacitor element 400 may be sealed with a sealing resin while housed in the capacitor case. In this case, the busbars 410 and 420 are provided such that the joints 414 and 424, which will be described later, are exposed from the sealing resin.

[0028] <Busba> Here, we will explain busbars 410 and 420 using Figures 2 to 7. Figure 5 is a simplified diagram showing the configuration of P busbar 420 and the positional relationship between P busbar 420 and inverter circuit 20.

[0029] Busbars 410 and 420 are conductive components. Busbars 410 and 420 connect at least the smoothing capacitor 42 to a plurality of phase arm elements 21 to 26 (inverter circuit 20). High-frequency current flows through busbars 410 and 420. N busbar 410 is part of the high-voltage N line 34. P busbar 420 is part of the high-voltage P line 33.

[0030] As shown in Figures 2 and 4, the N busbar 410 includes a capacitor connection portion 411, a bent portion 412, an extended portion 413, and a joint portion 414. The capacitor connection portion 411, the bent portion 412, the extended portion 413, and the joint portion 414 are constructed as a single unit. The N busbar 410 is formed, for example, by press working on a plate-shaped member.

[0031] The capacitor connection portion 411 is a flat plate-shaped portion. The capacitor connection portion 411 is provided along the XY plane. The capacitor connection portion 411 is positioned opposite the first electrode 401 of all capacitor elements 400. The capacitor connection portion 411 is connected to all first electrodes 401.

[0032] The bent portion 412 is the part connected to the capacitor connection portion 411. The bent portion 412 is the part that is bent in the Z direction relative to the capacitor connection portion 411. The capacitor connection portion 411 is provided on one end of the bent portion 412 in the Z direction. The extension portion 413 is provided on the other end of the bent portion 412 in the Z direction. The extension portion 413 is the part connected to the bent portion 412. The extension portion 413 is the part that is bent in the Y direction relative to the bent portion 412.

[0033] The joint portion 414 is a part connected to the extension portion 413. The joint portion 414 protrudes in the Y direction relative to the extension portion 413. The joint portion 414 is a part that is joined to a busbar different from the P busbar 420. The N busbar 410 has a capacitor connection portion 411 at one end in the Y direction and the joint portion 414 at the other end.

[0034] Note that the N busbar 410 in this embodiment is merely an example. The N busbar 410 may have a different shape than the one described above. Similarly, the P busbar 420 described below is also merely an example.

[0035] As shown in Figures 2, 3, and 4, the P busbar 420, like the N busbar 410, includes a capacitor connection portion 421, a bent portion 422, an extended portion 423, and a joint portion 424. The capacitor connection portion 421, the bent portion 422, the extended portion 423, and the joint portion 424 are constructed as a single unit. The P busbar 420 is formed, for example, by press working from a plate-shaped member.

[0036] Figures 5, 6, and 7 will be used to explain the differences between the P busbar 420 and the N busbar 410. Figure 5 shows a simplified flat plate shape of the P busbar 420, which includes a capacitor connection portion 421 and a joint portion 424. In other words, the bent portion 422 and the extended portion 423 are omitted in Figure 5.

[0037] Furthermore, in Figure 5, the junction 424 is shown in a simplified form. The junction 424 is electrically connected to the inverter circuit 20 (semiconductor switching element). The junction 424 can be considered as the input or output of the current flowing through the capacitor element 400. The junction 424 can also be considered one of the current terminals in the P busbar 420. In contrast, the capacitor connection 421 can be considered the other current terminal in the P busbar 420.

[0038] The P busbar 420 differs from the N busbar 410 in that the capacitor connection portion 421 is positioned opposite the second electrode 402. The capacitor connection portion 421 is positioned opposite the second electrode 402 of all capacitor elements 400. The capacitor connection portion 421 is connected to all second electrodes 402.

[0039] Furthermore, the P busbar 420 differs from the N busbar 410 in that it is provided with multiple holes 421h. In this embodiment, an example is adopted in which the holes 421h are provided in the capacitor connection portion 421. However, the holes 421h may be provided in places other than the capacitor connection portion 421. In other words, the holes 421h do not have to be provided in the region opposite the second electrode 402 in the Z direction.

[0040] As shown in Figure 5, the P busbar 420 has an annular side surface S3. Also, as shown in Figure 6, the P busbar 420 has one surface S1 and the opposite surface S2 of the surface S1. The surface S1 and the opposite surface S2 are connected to the side surface S3. The distance between the surface S1 and the opposite surface S2 corresponds to the plate thickness of the P busbar.

[0041] As shown in Figures 5 and 7, the P busbar 420 is provided with a hole 421h that penetrates in the thickness direction of the plate. The P busbar 420 is provided with multiple holes 421h. The multiple holes 421h are arranged in the X direction.

[0042] The hole 421h extends from one surface S1 to the opposite surface S2. The hole 421h does not reach the side surface S3 of the P busbar 420. In other words, the hole 421h is surrounded by the wall surface S4 of the P busbar 420. The hole 421h is a through hole. Multiple holes 421h have the same opening area. In this embodiment, as an example, a rectangular opening shape for the hole 421h is used. However, the opening shape of the hole 421h is not particularly limited.

[0043] As shown in Figures 2 and 5, an opposing member 500 is positioned on the P busbar 420. The hole 421h is provided at least at a position where the opposing member 500 faces each other.

[0044] <Opponent member> Here, we will explain the opposing member 500 using Figures 5, 6, and 7. The opposing member 500 is a magnetic material. The opposing member 500 is, for example, mainly composed of iron. The opposing member 500 can also be called a magnetic member or a magnetic plate.

[0045] The opposing member 500 is provided to form a region in the P busbar 420 where the inductance is partially increased. It can also be said that the opposing member 500 is provided to form a region in the P busbar 420 where current flow is reduced. Furthermore, it can be said that the opposing member 500 is provided to control the current distribution in the P busbar 420.

[0046] In this embodiment, a flat plate-shaped opposing member 500 is used as an example. However, the opposing member 500 may be the case of the power converter 100 or the like. The case integrally houses the boost converter circuit 10, the inverter circuit 20, the filter capacitor 41, and the smoothing capacitor 42, etc.

[0047] As shown in Figures 5 and 6, the opposing member 500 is positioned opposite at least a portion of the P busbar 420. It can also be said that the opposing member 500 is positioned to run parallel to the P busbar 420.

[0048] The opposing member 500 is positioned opposite the P busbar 420 with a gap between them. A gap (space) is formed between the opposing member 500 and the P busbar 420. However, a resin or the like may be provided between the opposing member 500 and the P busbar 420. In other words, a resin space or the above-mentioned sealing resin may be provided between the opposing member 500 and the P busbar 420 so that they do not come into contact with each other.

[0049] The opposing member 500 has an opposing surface S11 that faces the P busbar 420, and a non-opposing surface S12 which is the opposite surface to the opposing surface S11. The opposing surface S11 faces one surface S1. The opposing surface S11 and the non-opposing surface S12 are connected to the side surface S13. The distance between the opposing surface S11 and the non-opposing surface S12 corresponds to the plate thickness of the opposing member 500.

[0050] Furthermore, as shown in Figures 5 and 7, the opposing member 500 is provided at a position opposite to the hole 421h. The opposing member 500 is, for example, positioned opposite some of the multiple holes 421h.

[0051] <Effects> For example, in a configuration without the opposing member 500, the P busbar 420 has a parasitic inductance 420p, as shown in the equivalent circuit of Figure 9. On the other hand, in the power converter 100, the opposing member 500 is positioned opposite the P busbar 420. As shown in Figure 6, a magnetic flux is formed around the P busbar 420 when current flows through it. At least a portion of this magnetic flux passes through the opposing member 500. The opposing member 500, by passing the magnetic flux through it, forms a magnetic flux in a direction that opposes the current to the P busbar 420.

[0052] In other words, as shown in the equivalent circuit of Figure 8, an additional inductance 420a is formed in the P busbar 420 at the point where the opposing member 500 faces. Therefore, the inductance of the P busbar 420 is partially increased by the opposing member 500. To put it another way, the P busbar 420 has a portion with only parasitic inductance 420p and a portion where additional inductance 420a is formed in addition to the parasitic inductance 420p.

[0053] Therefore, current is less likely to flow through the P busbar 420 in the areas where the opposing members 500 are positioned opposite each other. In other words, current is less likely to flow through the P busbar 420 in the areas where the opposing members 500 are positioned opposite each other than in the areas where the opposing members 500 are not positioned opposite each other. As a result, the power converter 100 can control the current distribution in the smoothing capacitor 42 depending on the position of the opposing members 500 relative to the P busbar 420. In other words, the power converter 100 can control the current distribution to the smoothing capacitor 42.

[0054] Furthermore, the opposing member 500 is positioned opposite some of the multiple holes 421h. Therefore, as shown in Figure 7, when current flows through the area between the opposing holes 421h of the P busbar 420, a magnetic flux is formed around that area. At least a portion of this magnetic flux passes through the opposing member 500 and the holes 421h. As a result, the inductance of the P busbar 420 increases in the area between the holes 421h. Consequently, current flows even less easily through the area where the opposing member 500 is positioned opposite the P busbar 420.

[0055] Furthermore, areas where only parasitic inductance 420p exists can also be described as areas where opposing members 500 are not positioned opposite each other. On the other hand, areas where additional inductance 420a is formed in addition to parasitic inductance 420p can also be described as areas where opposing members 500 are positioned opposite each other.

[0056] Furthermore, the inductance of the P-busbar 420 is significantly affected when the current flowing through it becomes high frequency. Therefore, when the opposing member 500 is not provided, current tends to flow more easily to the part of the smoothing capacitor 42 that is closer to the junction 424. In other words, among the multiple capacitor elements 400 of the P-busbar 420, current tends to flow more easily to the capacitor element 400 that is closer to the junction 424. In this embodiment, when the opposing member 500 is not provided, the right side of the P-busbar 420 in the X direction is more prone to current flow. The state when the opposing member 500 is not provided can also be called the non-opposing state. Note that in the non-opposing state, the part where current tends to flow is not limited to the right side in the X direction, but may also be the left side or near the center.

[0057] In this case, the current flowing through the smoothing capacitor 42 will vary depending on the region. Therefore, the smoothing capacitor 42 may generate heat in certain areas. Also, it may not be possible to effectively utilize the entire surface area of ​​the smoothing capacitor 42.

[0058] However, as described above, the power converter 100 can control the current distribution to the smoothing capacitor 42 by the opposing member 500. Therefore, the power converter 100 can suppress variations in the current flowing to the smoothing capacitor 42 by arranging the opposing member 500 opposite to the part of the P busbar 420 where current flows easily. The opposing member 500 is positioned opposite to the P busbar 420, biased to the right side in the X direction. The part where current flows easily refers to the part where current flows easily in the non-opposing state.

[0059] This allows the power converter 100 to suppress localized heat generation in the smoothing capacitor 42. Furthermore, the power converter 100 can effectively utilize the entire surface area of ​​the smoothing capacitor 42. Additionally, the power converter 100 can be configured for even higher frequencies and the smoothing capacitor 42 can be miniaturized.

[0060] Furthermore, a structure comprising a capacitor element 400, an N busbar 410, a P busbar 420, and an opposing member 500 can also be called a capacitor device. The opposing member 500 may be positioned opposite the N busbar 410. In other words, the opposing member only needs to be positioned opposite at least one of the N busbar 410 and the P busbar 420.

[0061] The hole 421h is provided in at least one of the N busbar 410 and the P busbar 420. The hole 421h is provided in the busbars 410 and 420 in which the opposing member 500 is arranged opposite each other.

[0062] Busbars 410 and 420 do not necessarily have holes. The power converter 100 can control the current distribution in the smoothing capacitor 42 by the position of the opposing member 500 relative to the busbars 410 and 420, even if the busbars 410 and 420 do not have holes.

[0063] The opposing member 500 may be positioned as described above with respect to the busbar connected to the filter capacitor 41. This can also achieve the same effect.

[0064] The capacitor connection portion 421 can also be called the busbar base. Therefore, the P busbar 420 can also be said to have a hole 421h provided in the busbar base 421. In the following modified examples, the portion of the P busbar in which the hole is provided will be referred to as the busbar base.

[0065] (Variation 1) As shown in Figure 10, the power converter 100 of Modification 1 differs from the above embodiment in the configuration of the P busbar 4201. The P busbar 4201 is provided with a busbar base 4211. The P busbar 4201 is provided with a hole 421h1. The hole 421h1 reaches the side surface S3 of the P busbar 4201. Therefore, the hole 421h1 can also be described as a slit, notch, groove, etc. For this reason, the P busbar 4201 is provided with a busbar base 4211 that is branched into multiple parts. It can also be said that the P busbar 4201 is arranged in a comb-like manner.

[0066] The P busbar 4201 has a region where current flows easily near its center in the X direction. Therefore, the opposing member 500 is positioned opposite the P busbar 4201 near its center in the X direction. The power conversion device of Modification 1 can achieve the same effects as the embodiment described above.

[0067] (Modification 2) As shown in Figure 11, the power converter 100 of Modified Example 2 differs from Modified Example 1 in the configuration of the smoothing capacitor 42. The P busbar 4202 is provided with a busbar base 4212. The P busbar 4202 is provided with a hole 421h2. The busbar base 4212 is the same as the busbar base 4211. The hole 421h2 is the same as the hole 421h1. The smoothing capacitor 42 is provided with only one capacitor element 400. The power converter of Modified Example 2 can achieve the same effects as Modified Example 1.

[0068] (Variation 3) As shown in Figure 12, the power converter 100 of Modification 3 differs from Modification 1 in the configuration of the P busbar 4203. The P busbar 4203 includes a busbar base 4213. The P busbar 4202 is provided with a hole 421h3. The hole 421h3 reaches the side surface S3 of the P busbar 4201. Therefore, the P busbar 4203 has multiple branched busbar bases 4213. Furthermore, the branched portions of the busbar bases 4213 have different lengths.

[0069] The right side of the P busbar 4203 in the X direction is where current flows most easily. Therefore, the opposing member 500 is positioned opposite the P busbar 4203, biased towards the right side in the X direction. The power conversion device of Modified Example 3 can achieve the same effects as Modified Example 1.

[0070] (Modification 4) As shown in Figure 13, the power conversion device 100 of Modification 4 differs from the embodiment in the configuration of the P busbar 4204. The P busbar 4204 is provided with a busbar base 4214. The P busbar 4204 is provided with a through hole 421h4. The length of the hole 421h4 in the Y direction of the P busbar 4204 is different from that of the P busbar 420. The power conversion device of Modification 4 can achieve the same effects as the embodiment described above.

[0071] (Variation 5) As shown in Figure 14, the power conversion device 100 of Modified Example 5 differs from the above embodiment in the configuration of the P busbar 4205 and the opposing member 500. The P busbar 4205 is provided with a busbar base 4215. The P busbar 4205 is provided with through holes 421h5. The lengths of the multiple holes 421h5 of the P busbar 4205 differ from those of the P busbar 420. That is, the lengths of the multiple holes 421h5 differ in the Y direction. Also, the opening areas of the multiple holes 421h5 differ. In the P busbar 4205, the opening area of ​​the holes 421h5 decreases from right to left in the X direction. The opposing member 500 is arranged to face all of the holes 421h5. The power conversion device of Modified Example 5 can achieve the same effects as the above embodiment.

[0072] (Experimental variation 6) As shown in Figure 15, the power converter 100 of the modified example 6 differs from the above embodiment in the configuration of the P busbar 4206 and the opposing member 500. The P busbar 4206 includes a busbar base 4216. The P busbar 4206 is provided with a through hole 421h6. The opening shape of the hole 421h6 is circular. The busbar base 4216 is provided with a plurality of holes 421h6.

[0073] The opposing member 500 has a triangular planar shape. The area of ​​the opposing member 500 that faces the P busbar 4206 increases as it moves from the joint 424 towards the capacitor element 400.

[0074] The right side of the P busbar 4206 in the X direction is where current flows most easily. Therefore, the opposing member 500 is positioned opposite the P busbar 4206, biased towards the right side in the X direction. The power conversion device of Modified Example 6 can achieve the same effects as the embodiment described above.

[0075] (Example 7) As shown in Figures 16 and 17, the power conversion device 100 of Modification 7 differs from the above embodiment and Modification 1 in the configuration of the P busbar 4207 and the opposing member 500.

[0076] As shown in Figure 16, the P busbar 4207 includes a busbar base 4217. The P busbar 4207 is provided with a hole 421h7, similar to the first modification. The P busbar 4207 differs from the first modification in the position of the joint 424. The joint 424 is located on the right side in the X direction. As shown in Figure 17, the multiple branched portions of the busbar base 4217 are at the same position in the Z direction. That is, the multiple branched portions of the busbar base 4217 are arranged parallel to the XY plane.

[0077] The right side of the P busbar 4207 in the X direction is a region where current flows easily. The portion extending in the Y direction from the junction 424 is also a region where current flows easily. As shown in Figure 17, the portion extending in the Y direction from the junction 424 is denoted by reference numeral 421x. Reference numeral 421x is the shortest portion of the P busbar 4207, which is the shortest path between the semiconductor switching element and the smoothing capacitor 42.

[0078] The opposing member 500 is positioned opposite at least the shortest portion 421x. The shortest portion 421x is a portion where current flow should be restricted. In other words, the shortest portion 421x is a portion where current flow should be restricted more than at other portions of the P busbar 420.

[0079] Therefore, as shown in Figure 17, the opposing member 500 is provided at an inclination with respect to the XY plane. Specifically, the distance between the shortest portion 421x and the opposing member 500 is provided to be narrower than the distance between the opposing member 500 and a portion of the P busbar 420 that is different from the shortest portion 421x. Here, the distance is in the Z direction. The power conversion device of Modification 7 can achieve the same effects as the embodiment described above.

[0080] (Variation 8) As shown in Figure 18, the power converter 100 of Modification 8 differs from Modification 7 in the configuration of the opposing member 500. The P busbar 4208 is the same as the P busbar 4207. In Figure 18, for convenience, the reference numerals of the busbar base 4218 and the hole 421h8 have been changed.

[0081] The opposing member 500 includes a first flat portion 501, a second flat portion 503, and a stepped portion 502 connected to the first flat portion 501 and the second flat portion 503. The opposing member 500 has a shape in which the positions of the first flat portion 501 and the second flat portion 503 in the Z direction are different due to the stepped portion 502. The first flat portion 501 is located closer to the P busbar 4208 than the second flat portion 503.

[0082] The first flat portion 501 is positioned opposite at least the shortest portion 421x. The second flat portion 503 is positioned opposite at least a portion different from the shortest portion 421x in the P busbar 4207. As a result, the distance between the shortest portion 421x and the opposing member 500 is narrower than the distance between the opposing member 500 and a portion different from the shortest portion 421x in the P busbar 4207. The power conversion device of Modification 8 can achieve the same effects as the above embodiment.

[0083] (Extreme variation 9) As shown in Figure 19, the power converter 100 of Modification 9 differs from Modification 7 in the configuration of the P busbar 4209 and the opposing member 500. The P busbar 4209 is provided with a busbar base 4219. The P busbar 4209 is provided with a hole 421h9, similar to Modification 1. The multiple branched portions of the busbar base 4219 are at different positions in the Z direction. Therefore, the multiple branched portions of the busbar base 4219 have different distances from the opposing member 500.

[0084] As a result, the distance between the shortest portion 421x and the opposing member 500 is set to be narrower than the distance between a portion other than the shortest portion 421x in the P busbar 4207 and the opposing member 500. The power conversion device of Modified Example 9 can achieve the same effect as Modified Example 7.

[0085] This disclosure is described in accordance with embodiments, but it is understood that this disclosure is not limited to such embodiments or structures. This disclosure also includes various modifications and variations within the scope of equivalents. In addition, while various combinations and forms are shown in this disclosure, other combinations and forms that include one, more, or fewer of those elements also fall within the scope and idea of ​​this disclosure. [Explanation of symbols]

[0086] 10...Boost converter circuit, 11...Upper arm element, 12...Lower arm element, 13...Reactor, 20...Inverter circuit, 21...U-phase upper arm element, 22...U-phase lower arm element, 23...V-phase upper arm element, 24...V-phase lower arm element, 25...W-phase upper arm element, 26...W-phase lower arm element, 41...Filter capacitor, 42...Smoothing capacitor, 410...N busbar, 420, 4201~4209...P busbar, 500...Opposite member, 100...Power conversion device

Claims

1. Semiconductor switching elements (21-26) and Capacitor (42) and A conductive busbar (410, 420, 4201-4209) connects the semiconductor switching element and the capacitor, A power conversion device comprising a magnetic material opposing member (500) positioned opposite at least a portion of the busbar.

2. The busbar is provided with holes (421h, 421h1 to 421h9) that penetrate in the thickness direction of the plate. The power conversion device according to claim 1, wherein the hole is provided at least at a position where the opposing members face each other.

3. The power conversion device according to claim 1 or 2, wherein the opposing member is positioned opposite the shortest portion (421x) in the busbar that is the shortest path between the semiconductor switching element and the capacitor.

4. The power conversion device according to claim 3, wherein the distance between the shortest portion and the opposing member is narrower than the distance between a portion different from the shortest portion in the busbar and the opposing member.

5. The power conversion device according to claim 2, wherein the hole is surrounded by the wall surface (S4) of the busbar.

6. The power conversion device according to claim 2, wherein the hole reaches the side surface (S3) of the busbar.

7. The power conversion device according to claim 1 or 2, wherein the capacitor includes a plurality of capacitor elements connected in parallel.

8. The power conversion device according to claim 1 or 2, wherein the capacitor includes only one capacitor element.

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