JP7283429B2 - power converter - Google Patents

Description

The present disclosure relates to power converters.

The power conversion device of Patent Literature 1 has two busbars, one of which is arranged inside the hollow of the other busbar. Furthermore, the power conversion device is provided with a refrigerant path through which the refrigerant passes between one bus bar and the other bus bar.

JP 2016-158426 A

Since the busbar allows the refrigerant to pass through the refrigerant passage, it is necessary to increase the thickness of the busbar in order to withstand the pressure of the refrigerant. Therefore, the thickness of the bus bar increases, which may lead to an increase in the size of the power converter.

The present disclosure has been made based on this situation, and an object thereof is to provide a power conversion device capable of improving the heat transfer of the busbar while suppressing the increase in size of the busbar. .

A first aspect of the present disclosure for achieving the object is a power conversion unit that converts supplied power and supplies it to a load, and a first bus bar and a second bus bar that are connected to the power conversion unit or the load. , and an insulating resin that is in contact with the first bus bar and the second bus bar and has a higher thermal conductivity per unit area than air, and the first bus bar is in contact with the outer surface of the arrangement portion of the second bus bar. The power conversion device has a peripheral portion covered with a spaced surface, and the insulating resin connects at least a portion of the outer surface of the placement portion and at least a portion of the inner surface of the peripheral portion. The power conversion device has communication holes (28) penetrating through the arrangement portion, the surrounding portion and the insulating resin.

In the power conversion device, the arrangement portion and the surrounding portion are connected by an insulating resin. Furthermore, since the thermal conductivity of the insulating resin is higher than that of air, the power conversion device can improve the heat transfer between the busbars as compared with the power conversion device in which the insulating resin is not arranged between the busbars.

In addition, since the inner surface of the peripheral portion and the outer surface of the placement portion are connected by the insulating resin, the stress applied to itself can be reduced as compared with a configuration in which the insulating resin is not connected. Therefore, the thickness of the peripheral portion and the placement portion can be reduced. Therefore, it is possible to prevent the peripheral portion and the placement portion from increasing in size.

1 shows a circuit diagram of a power conversion system according to a first embodiment; FIG. It is the figure which showed the structure of P bus bar of 1st Embodiment, and N bus bar. FIG. 3 is a view in the direction of arrow III in FIG. 2; FIG. 3 is a sectional view taken along IV-IV in FIG. 2; FIG. 3 is a cross-sectional view taken along line VV of FIG. 2; It is sectional drawing of P bus bar of 2nd Embodiment, and N bus bar. It is the figure which showed the structure of P bus bar of 3rd Embodiment, and N bus bar. FIG. 8 is a cross-sectional view taken along line VIII-VIII of FIG. 7; It is the figure which showed the structure of the N bus bar of the 4th comparative example. It is the figure which showed the structure of P bus bar of 3rd Embodiment, and N bus bar.

A plurality of embodiments of the present disclosure will be described below based on the drawings. Note that redundant description may be omitted by assigning the same reference numerals to corresponding components in each embodiment. When only a part of the configuration is described in each embodiment, the configurations of other embodiments previously described can be applied to the other portions of the configuration. Moreover, not only the combinations of the configurations explicitly specified in the description of each embodiment, but also the configurations of a plurality of embodiments can be partially combined even if they are not specified unless there is a particular problem with the combination. Also, unspecified combinations of configurations described in a plurality of embodiments and modifications are also disclosed by the following description.

(First embodiment)
As shown in FIG. 1, the power conversion system 1 includes a battery 11, a power conversion device 12 and a motor 13. Battery 11 supplies DC current to power converter 12 via P bus bar 20 and N bus bar 21 . The power converter 12 converts, for example, a direct current into a three-phase alternating current in the power conversion unit 23a, and supplies the three-phase alternating current to the motor 13 via the three-phase bus bar 24 for the motor.

A load in the present disclosure is, for example, the motor 13 . The motor 13 is, for example, a three-phase AC motor having three phases of U phase, V phase and W phase. In this embodiment, the longitudinal direction in which the N-side connection terminal 21a shown in FIG. 2 extends is defined as the X direction. The direction in which the plurality of power conversion switching elements 23b shown in FIG. 2 are stacked is defined as the Y direction. The longitudinal direction in which the P terminal 23P shown in FIG. 3 extends is defined as the Z direction.

The power conversion device 12 has a power conversion section 23 a , a P bus bar 20 , an N bus bar 21 , a three-phase motor bus bar 24 , a smoothing capacitor 22 , an insulating resin 25 and a step-up/down section 27 .

The power converter 23a has a plurality of power conversion switching elements 23b. The power conversion switching element 23b includes a P terminal 23P, an output terminal 23e and a signal terminal 23S as shown in FIG. Further, the power conversion switching element 23b includes an N terminal 23N, an output terminal 23e and a signal terminal 23S. The two types of power conversion switching elements 23b are arranged side by side in the X direction.

As shown in FIG. 2, the plurality of power conversion switching elements 23b are stacked in the Y direction with two types of power conversion switching elements 23b as one set. The plurality of power conversion switching elements 23b are stacked in the Y direction via, for example, a plurality of refrigerant pipes (not shown) through which cooling refrigerant flows.

In other words, the power conversion switching elements 23b are arranged on both sides of the refrigerant pipe in the Y direction. The refrigerant pipe and the power conversion switching element 23b are in direct contact, for example, and the heat generated by the P-side switching element 23c is transferred to the refrigerant pipe. Alternatively, the refrigerant pipe and the P-side switching element 23c are arranged close to each other in the Y direction.

As shown in FIG. 3, the P terminal 23P and the N terminal 23N are formed so that the longitudinal direction extends in the Z direction. The extending direction of the P terminal 23P and the N terminal 23N is perpendicular to the extending direction of the P side connection terminal 20a and the N side connection terminal 21a. The P-terminal 23P is in contact with the P-side connecting terminal 20a at the surfaces thereof facing each other in the Y direction, and is connected by welding, for example.

The surfaces of the N terminal 23N and the N side connection terminal 21a facing each other in the Y direction are in contact with each other and are connected by welding. The welded portion between the P terminal 23P and the P-side connecting terminal 20a and the welded portion between the N-terminal 23N and the N-side connecting terminal 21a have approximately the same height in the Z direction. Since the two welding locations have approximately the same height in the Z direction, welding can be performed efficiently during welding.

As shown in FIG. 1 , the smoothing capacitor 22 is connected to the positive terminal of the battery 11 through the P busbar 20 and connected to the negative terminal of the battery 11 through the N busbar 21 . Also, the smoothing capacitor 22 is connected to the power converter 23 a via the P bus bar 20 and the N bus bar 21 . The smoothing capacitor 22 smoothes the voltage of the current supplied from the battery 11 and supplies it to the power converter 23a.

As shown in FIG. 1, the step-up/step-down unit 27 is arranged between the battery 11 and the power conversion unit 23a. The step-up/step-down unit 27 has a step-up/step-down switching element 27 a , a reactor 29 and a filter capacitor 30 . The step-up/step-down unit 27 steps up the voltage of the current supplied from the battery 11 by switching the step-up/step-down switching element 27a. Then, the step-up/step-down unit 27 supplies the stepped-up current to the motor 13 via the power conversion unit 23a. The motor 13 performs a power running operation with electric power supplied via the step-up/step-down unit 27 and the power conversion unit 23a.

The step-up/step-down unit 27 is supplied with electric power generated by the regenerative operation of the motor 13 via the power conversion unit 23a. The step-up/step-down unit 27 steps down the voltage of the supplied electric power by switching the step-up/step-down switching element 27 a and supplies the voltage to the battery 11 .

In the present disclosure, the first busbar is the N busbar 21, for example. As shown in FIG. 4, the N bus bar 21 has a peripheral portion 21g, an N-side capacitor terminal 21b, and an N-side connection terminal 21a. The peripheral portion 21g is, for example, annular. The peripheral portion 21g forms a hollow first hollow 21h inside an annular shape. That is, the first hollow 21h is surrounded by the inner surface of the peripheral portion 21g.

The N bus bar 21 has a first hollow 21h formed inside a peripheral portion 21g from one end surface to the other end surface in the X direction. That is, the N bus bar 21 has a cylindrical shape with a first hollow 21h formed from one end to the other end in the X direction.

As shown in FIG. 2, the peripheral portion 21g has, for example, an N-side capacitor terminal 21b extending in the longitudinal direction from the outer surface to one side in the X direction. The N-side capacitor terminal 21b is in contact with a bus bar (not shown) connected to the negative electrode of the smoothing capacitor 22, for example.

As shown in FIG. 2, the peripheral portion 21g has, for example, an N-side connection terminal 21a extending in the longitudinal direction from the outer surface to the other side in the X direction. The surfaces of the N-side connection terminal 21a and the N-terminal 23N are in contact with each other in the Y direction. Therefore, the negative electrode of smoothing capacitor 22 and N terminal 23N are electrically connected via N bus bar 21 .

In the present disclosure, the second busbar is the P busbar 20, for example. As shown in FIG. 2, the P bus bar 20 has an arrangement portion 20c, a switch connection portion 20d, a capacitor connection portion 20e, a P-side connection terminal 20a, and a P-side capacitor terminal 20b. The arrangement portion 20c is arranged inside the peripheral portion 21g as shown in FIG. Further, the outer surface of the arrangement portion 20c is arranged with a constant distance from the inner surface of the peripheral portion 21g. As shown in FIG. 2, the arrangement portion 20c is formed so as to extend in the Y direction, for example.

As shown in FIG. 2, the P bus bar 20 has a switch connection portion 20d extending from the placement portion 20c to the other side in the X direction. The switch connection portion 20d is integrated with the placement portion 20c, but is placed outside the first hollow 21h. That is, the outer surface of the switch connection portion 20d does not face the inner surface of the peripheral portion 21g.

As shown in FIG. 2, the switch connection portion 20d has a P-side connection terminal 20a whose longitudinal direction extends from the outer surface to the other side in the X direction. The surfaces of the P-side connection terminal 20a and the P-terminal 23P are in contact with each other in the Y direction. Moreover, as shown in FIGS. 2 and 3, the P-side connection terminal 20a is arranged so as to overlap with the N-side connection terminal 21a in the Z direction. As shown in FIG. 3, the P-side connection terminal 20a is different in height in the Z-direction from the N-side connection terminal 21a in the range where it overlaps with the N-side connection terminal 21a in the Z-direction.

The welded portion of the P-side connection terminal 20a to the P-terminal 23P is different in position in the X direction from the welded portion of the N-side connection terminal 21a to the N-terminal 23N. The P-side connection terminal 20a has a portion extending in the Z-direction so that only the welded portion has approximately the same height in the Z-direction as the N-side connection terminal 21a, in order to increase welding efficiency.

As shown in FIG. 2, the P bus bar 20 has a capacitor connection portion 20e extending from the placement portion 20c to one side in the X direction. The capacitor connection portion 20e is integrated with the placement portion 20c, but is placed outside the first hollow 21h. That is, the outer surface of the capacitor connection portion 20e does not face the inner surface of the peripheral portion 21g.

As shown in FIG. 2, the capacitor connecting portion 20e has a P-side capacitor terminal 20b extending from the outer surface to one side in the X direction in the longitudinal direction. The P-side capacitor terminal 20b is in contact with a bus bar (not shown) connected to the positive electrode of the capacitor. Therefore, smoothing capacitor 22 and P terminal 23P are electrically connected via P bus bar 20 .

The insulating resin 25 is filled between the inner surface of the peripheral portion 21g and the outer surface of the placement portion 20c as shown in FIG. That is, the insulating resin 25 is filled in the first hollow 21h. Therefore, the entire inner surface of the peripheral portion 21g and the entire outer surface of the placement portion 20c are connected via the insulating resin 25. As shown in FIG.

Also, the insulating resin 25 is a material having a higher thermal conductivity per unit area than air. It is desirable that the insulating resin 25 has a coefficient of linear expansion close to that of the P bus bar 20 and the N bus bar 21 .

FIG. 5 is a diagram showing a VV cross section in FIG. A VV cross section is a cross section perpendicular to the conducting direction of the N-side connection terminal 21a. As shown in FIG. 5, the N-side connection terminal 21a forms a first hollow 21h with a peripheral portion 21g. The peripheral portion 21g has a flat shape having a portion forming the long side 21c and a portion forming the short side 21d.

A connecting portion 21e connecting the long side 21c and the short side 21d has, for example, an arc shape. In FIG. 5, the long side 21c, the connecting portion 21e and the short side 21d are integral. Further, the connecting portion 21e and the short side 21d are in the shape of a continuous arc.

The N-side connection terminal 21a is formed by processing one plate, for example. As shown in FIG. 5, the N-side connection terminal 21a has one end and the other end in contact with each other by folding back the plate. Furthermore, the N-side connection terminal 21a has a welded portion 26 where one end and the other end are welded. The welded portion 26 is provided at a portion forming the long side 21c of the peripheral portion 21g. The welding portion 26 is in contact with and electrically connected to the surface of the N terminal 23N on the other Y-direction surface.

FIG. 4 is a diagram showing a IV-IV cross section in FIG. A IV-IV cross section is a cross section perpendicular to the direction of conduction of the P bus bar 20 . The cross sections of the peripheral portion 21g and the placement portion 20c are flat. The area of the first cross section S1 of the arrangement portion 20c shown in FIG. 4 is larger than the area of the second cross section S2 of the peripheral portion 21g. Also, the area of the first cross section S1 is preferably larger than the area of the second cross section S2.

As shown in FIG. 4, the insulating resin 25 is filled between the outer surface of the placement portion 20c and the inner surface of the peripheral portion 21g. Furthermore, the insulating resin 25 has a higher thermal conductivity per unit length than air. Therefore, the placement portion 20c can transfer heat to the surrounding portion 21g through the insulating resin 25 and release it, compared to a configuration without the insulating resin 25. As shown in FIG. The power conversion device 12 can dissipate the heat generated in the arrangement portion 20c to the surrounding portion 21g more than the configuration without the insulating resin 25 .

Since the heat of the placement portion 20c can be released to the surrounding portion 21g by the insulating resin 25, the electric power conversion device 12 eliminates the need to flow a coolant between the surrounding portion 21g and the placement portion 20c for cooling the placement portion 20c. Therefore, the power conversion device 12 can reduce the pressure from the refrigerant applied to the surrounding portion 21g and the arrangement portion 20c. Therefore, the power conversion device 12 can reduce the thickness of the peripheral portion 21g and the placement portion 20c. As described above, the power conversion device 12 can suppress an increase in the size of the busbar while improving the heat transfer of the busbar.

Since the peripheral portion 21g and the arrangement portion 20c are supported by the insulating resin 25, stress applied thereto can be reduced. Furthermore, since the peripheral portion 21g and the placement portion 20c are supported by the insulating resin 25, there is no need to provide a support member to separate the inner surface of the peripheral portion 21g and the outer surface of the placement portion 20c.

Also, the thinner the insulating resin 25 is, the smaller its own thermal resistance can be. Therefore, by making the thickness of the insulating resin 25 as thin as possible while supporting the peripheral portion 21g and the placement portion 20c, the heat of the placement portion 20c can be efficiently released to the peripheral portion 21g.

A first comparative example includes N busbars having a hollow. The cross section of the N bus bar of the first comparative example has a tubular shape and does not have a long side. Therefore, when the N bus bar of the first comparative example comes into contact with another member on its outer surface, it contacts with a curved surface and cannot come into contact with a flat surface.

On the other hand, the peripheral portion 21g of this embodiment has a portion forming the long side 21c as shown in FIG. Peripheral portion 21g is in contact with N terminal 23N on the outer surface of the portion forming long side 21c. The outer surface of the portion forming the long side 21c has a planar shape. Therefore, the peripheral portion 21g can contact the N terminal 23N over a larger area than in the first comparative example, which cannot contact with a flat surface. Therefore, the peripheral portion 21g can efficiently release heat generated by energization or the like to another member, such as the N terminal 23, through the portion forming the long side.

As shown in FIG. 5, the peripheral portion 21g is directly connected to the N terminal 23N at the welding portion 26. As shown in FIG. Therefore, the peripheral portion 21g conducts heat more easily to the N terminal 23N than a configuration in which the peripheral portion 21g is connected via a fastening member or the like. Furthermore, since the peripheral portion 21g does not include a fastening member or the like, an increase in inductance due to the fastening member or the like can be suppressed.

A second comparative example includes an N bus bar having a hollow and a P bus bar arranged in the hollow of the N bus bar. The cross-sectional area of the P busbar in the second comparative example is smaller than the cross-sectional area of the N busbar. Therefore, the P bus bar of the second comparative example has a larger resistance when current flows than the N bus bar. Therefore, the P bus bar of the second comparative example generates more heat than the N bus bar when current flows.

In addition, since the P bus bar of the second comparative example is arranged in the hollow of the N bus bar, it is more difficult for heat to escape than the N bus bar whose entire outer surface is not surrounded by other members. Therefore, the P bus bar of the second comparative example may reach a high temperature due to heat generated during energization.

On the other hand, as shown in FIG. 4, the area of the first cross section S1 of the arrangement portion 20c of the present embodiment is larger than the area of the second cross section S2 of the peripheral portion 21g. Therefore, the arrangement portion 20c can suppress the generation of heat greater than that of the surrounding portion 21g. Therefore, the arrangement portion 20c can prevent itself from becoming hot.

In the configuration shown in FIG. 1 , the current supplied to the step-up/step-down unit 27 by, for example, the regenerative operation of the motor 13 flows from the step-up/step-down unit 27 to the N bus bar 21 . Further, when the motor 13 is in power running operation, the current supplied from the battery 11 to the motor 13 flows from the motor 13 to the N bus bar 21 via the power converter 23a. Therefore, the N bus bar 21 may merge currents flowing due to the operation of the motor 13 and the step-up/down section 27 . In that case, the N busbar 21 may generate more heat than the P busbar 20 .

A third comparative example includes a P bus bar having a hollow and an N bus bar arranged inside the hollow. The N bus bar of the third comparative example has the entire outer surface surrounded by the inner surface of the P bus bar. Furthermore, since the N bus bar merges the currents generated by the operations of the motor 13 and the step-up/down unit 27 as described above, a large current may flow therethrough. In that case, since the N bus bar of the third comparative example has the entire outer surface surrounded by the inner surface of the P bus bar, it may not be possible to dissipate the large amount of heat generated by the large current.

On the other hand, the peripheral portion 21g of this embodiment is arranged outside the arrangement portion 20c. The outer surface of the peripheral portion 21g is not entirely surrounded by other members. Therefore, even when a large amount of current flows, the peripheral portion 21g can release heat from the outer surface to the outside, so that the temperature can be suppressed from becoming higher than in the third comparative example.

The insulating resin 25 is a material having a coefficient of linear expansion close to that of the P bus bar 20 and the N bus bar 21 . Therefore, when insulating resin 25, P bus bar 20 and N bus bar 21 expand due to heat or the like, insulating resin 25, P bus bar 20 and N bus bar 21 expand to the same extent. Therefore, the arrangement portion 20c and the surrounding portion 21g can reduce the stress received by the insulating resin 25 from expanding.

(Second embodiment)
The power conversion system 1 in this embodiment has the same configuration as in the first embodiment. Therefore, in this embodiment, the same reference numerals as in the first embodiment are used. Note that in this embodiment, differences from the first embodiment will be mainly described.

As shown in FIG. 6, the insulating resin 25 is in contact with a portion of the inner surface of the peripheral portion 21g and a portion of the outer surface of the placement portion 20c. As compared with a configuration in which the insulating resin 25 is not arranged, the peripheral portion 21g and the arrangement portion 20c are supported by the insulating resin 25, and thus deformation is suppressed even when stress is applied.

Therefore, the peripheral portion 21g and the placement portion 20c can withstand the pressure received from the coolant or the like, compared to a configuration in which the insulating resin 25 is not placed. Therefore, the thickness of the peripheral portion 21g and the arrangement portion 20c can be reduced.

Since the insulating resin 25 is arranged in the first hollow 21h, the peripheral portion 21g and the arrangement portion 20c are insulated from the heat generated in the arrangement portion 20c compared to a configuration in which the insulating resin 25 is not arranged. It can be transmitted through the resin 25 to the peripheral portion 21g.

FIG. 6 is a diagram showing a cross section of the arrangement portion 20c and the peripheral portion 21g in this embodiment. The placement portion 20c is a tubular portion 20f that forms a second hollow 20g inside. That is, the second hollow 20g is surrounded by the inner surface of the tubular portion 20f. The tubular portion 20f can release heat generated by energization or the like to the second hollow 20g.

Further, the tubular portion 20f can flow the refrigerant to the second hollow 20g. That is, the inner surface of the tubular portion 20f is used as the coolant passage 20h. That is, the tubular portion 20f is in contact with the coolant on the inner surface of the tubular portion 20f. Therefore, the tubular portion 20f releases heat to the coolant from the inner surface, and can be cooled more efficiently than the configuration in which the arrangement portion 20c does not have the coolant passage 20h.

Further, the second hollow 20g of the tubular portion 20f may be filled with insulating resin. The tubular portion 20f can release heat to the insulating resin 25 by filling the insulating resin 25 in the second hollow 20g.

Therefore, the tubular portion 20f can reduce the stress applied to the tubular portion 20f compared to a configuration in which the insulating resin 25 is not arranged in the second hollow 20g. Therefore, the thickness of the tubular portion 20f can be reduced.

(Third Embodiment)
The power conversion system 1 in this embodiment has the same configuration as in the first embodiment. Therefore, in this embodiment, the same reference numerals as in the first embodiment are used. Note that in this embodiment, differences from the first embodiment will be mainly described.

FIG. 7 is a diagram showing the P busbar 20 and the N busbar 21 in this embodiment. FIG. 8 is a diagram showing the VIII-VIII section of FIG. As shown in FIG. 8, the placement portion 20c, the surrounding portion 21g, and the insulating resin 25 are formed with a communication hole 28 penetrating inside and outside. The communication hole 28 has an upper opening 28a in a portion forming the long side 21c on one side in the Z direction. Furthermore, the communication hole 28 has a lower opening 28b in a portion forming the long side 21c on the other side in the Z direction.

The communication hole 28 is continuously formed so as to penetrate from the upper opening 28a to the lower opening 28b. In other words, the communication hole 28 forms a hollow in the range connecting the upper opening 28a and the lower opening 28b, and penetrates the insulating resin 25, the arrangement portion 20c, and the peripheral portion 21g.

The peripheral portion 21g and the placement portion 20c can release heat generated by energization or the like to the communication hole . In addition, the surrounding portion 21g and the arrangement portion 20c allow natural convection to flow through the communication hole 28, so that the heat generated by the busbar can be released to the outside through the communication hole 28. As shown in FIG. Furthermore, the peripheral portion 21g and the arrangement portion 20c can allow the coolant to flow through the communication holes 28. As shown in FIG. Surfaces of the peripheral portion 21g and the placement portion 20c forming the communication hole 28 come into contact with the coolant. Therefore, the surrounding portion 21g and the arrangement portion 20c are cooled by the coolant flowing through the communication holes 28. As shown in FIG.

Although a plurality of communication holes 28 are formed in the peripheral portion 21g and the arrangement portion 20c in FIG. 8, the number of the communication holes 28 may be singular or plural. FIG. 8 discloses an example in which the communicating hole 28 penetrates from the upper opening 28a to the lower opening 28b. It does not have to reach the other portion forming the side 21c.

Further, the communication hole 28 is provided in a portion forming the long side 21c of the peripheral portion 21g. A portion forming the short side 21d of the peripheral portion 21g has a curved shape. On the other hand, as shown in FIG. 9, the N bus bar 121 of the fourth comparative example has a communicating hole 128 in the portion forming the short side 121d.

In FIG. 9, reference numerals added by 100 are assigned to the configurations corresponding to the configurations of the present embodiment. That is, for example, since the long side of the present embodiment is the long side 21c, the long side of the fourth comparative example in FIG. 9 is given the long side 121c.

The communication hole 128 has an opening 128a that opens outward. The opening 128a has corners 128c. The N bus bar 121 of the fourth comparative example faces the motor three-phase bus bar 124a with a distance d at the portion forming the short side 121d.

When the voltage between two members is V and the distance between the two members is d, the voltage concentration E on the member is expressed as E=η·V/d. η indicates a non-uniformity factor, and its value varies depending on the shape of the faces of the members facing each other.

The non-uniformity ratio η becomes smaller as the shape of the facing surfaces of the members is closer to a plane, that is, as the facing area becomes larger, and becomes larger as the facing area becomes smaller like a needle. The N busbars 121 of the fourth comparative example face each other at the portions forming the curved short sides 121d. Therefore, the N busbars 121 of the fourth comparative example have a larger non-uniformity ratio η than when they face each other on a plane.

Further, the N bus bar 121 has a corner portion 128c formed in a portion forming the short side 121d. Since the corner portion 128c has a smaller area that can face another member than the flat surface, the non-uniformity ratio η is larger than that of the flat surface.

Therefore, since the N bus bar 121 faces the motor three-phase bus bar 124a at the corner 128c formed on the short side 121d, there is a possibility that the non-uniformity ratio η will increase. If the voltage concentration at the corner 128c exceeds the withstand voltage of the material, the N bus bar 121 may cause dielectric breakdown with the facing three-phase motor bus bar 124a.

On the other hand, as shown in FIG. 10, the peripheral portion 21g is provided with a communicating hole 28 in a portion forming the planar long side 21c. Therefore, since the N bus bar 21 is provided in the portion where the corner portion 28c forms the long side, it is possible to suppress an increase in the unequal rate η. Therefore, the peripheral portion 21g can suppress the occurrence of dielectric breakdown between the opposing member, for example, the first motor three-phase bus bar 24a.

(Other embodiments)
Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments, and the following embodiments are also included in the technical scope of the present disclosure. Various changes can be made within a range that does not deviate.

In the above-described embodiment, the peripheral portion 21g and the tubular portion 20f are described as having an annular shape.

In the above embodiment, the placement portion 20c is arranged inside the N busbar 21. However, in two busbars applied to different parts, one busbar is arranged inside the other busbar. can be For example, among the three-phase busbars 24a for the first motor, the U-phase busbar may be configured to be spaced apart inside the V-phase busbar. In this case, the insulating resin 25 that contacts and connects at least a portion of the outer surface of the U-phase bus bar and at least a portion of the inner surface of the V-phase bus bar disposed inside the V-phase bus bar is connected to the U-phase bus bar and the V-phase bus bar. It is placed between the busbars.

In the above-described embodiment, the placement portion 20 c is arranged inside the N bus bar 21 , but at least part of the N bus bar may be arranged inside the P bus bar 20 . In that case, an insulating resin 25 that contacts at least part of the inner surface of the P bus bar 20 and at least part of the N bus bar is arranged between the P bus bar 20 and the N bus bar 21 .

Similarly, the configuration described as the configuration of the P bus bar 20 in the above embodiment may also be applied to the N bus bar 21 . Similarly, the configuration described as the configuration possessed by the N bus bar 21 may be applied to the P bus bar 20 as well.

In the above embodiment, the switch connection portion 20d and the capacitor connection portion 20e are described as separate structures, but they may have the same structure. For example, the switch connection portion 20d may have a shape having a P-side connection terminal 20a and a P-side capacitor terminal 20b.

Although the P bus bar 20 has been described as having the switch connection portion 20d and the capacitor connection portion 20e, it may be configured without the switch connection portion 20d and the capacitor connection portion 20e. In this case, the P-side connection terminal 20a and the P-side capacitor terminal 20b are formed to extend in the X direction from the arrangement portion 20c.

In the above-described embodiment, the cross sections of the P bus bar 20 and the N bus bar 21 are described as having a flat shape, but they may have a shape other than a flat shape having no long sides, such as a circle.

Although the P bus bar 20 described in the second embodiment is described as having the tubular portion 20f, it may be configured without the tubular portion 20f.

Although the N bus bar 21 is described as having the welded portion 26, it may be configured to be connected using a fastening member or the like for connection with other members.

Although the area of the first cross section S1 is described as being equal to or larger than the area of the second cross section S2, it may be configured to be smaller than the area of the second cross section S2.

In the present disclosure, the N-side connection terminal 21a is described as having the peripheral portion 21g, but may be configured without the peripheral portion 21g, that is, without the first hollow 21h. However, the N bus bar 21 has a peripheral portion 21g in a portion other than the N side connection terminal 21a.

11... battery, 13... motor (load), 20... P bus bar (second bus bar), 20c... placement portion, 20f... tubular portion, 21... N bus bar (first bus bar), 21c long side, 21d short side, 21g peripheral portion, 23a electric power converter, 25 insulating resin, 26 welding portion, 28 Communicating hole, S1: first cross section, S2: second cross section, 27: step-up/down section

Claims (9)

a power converter (23a) that converts the supplied power and supplies it to a load (13);
a first bus bar (21) and a second bus bar (20) connected to the power conversion unit or the load;
an insulating resin (25) in contact with the first bus bar and the second bus bar and having a higher thermal conductivity per unit area than air;
The first bus bar has a peripheral portion (21g) covered with an inner surface spaced apart from the outer surface of the placement portion (20c) of the second bus bar,
the insulating resin connects at least a portion of the outer surface of the placement portion and at least a portion of the inner surface of the peripheral portion;
A power conversion device having a communication hole (28) penetrating through the arrangement portion, the surrounding portion and the insulating resin . 2. The power conversion device according to claim 1 , wherein a space between said placement portion and said surrounding portion is filled with said insulating resin . At least one of the peripheral portion and the arrangement portion according to claim 1 or claim 2, wherein a cross section perpendicular to the direction of current flow has a flat shape having a long side (21c) and a short side (21d) . Power converter. The power converter according to any one of claims 1 to 3 , wherein the arrangement portion is a tubular portion (20f) . 5. The power converter according to claim 4 , wherein the inside of said tubular portion is filled with an insulating resin having a higher thermal conductivity per unit area than air . 2. The area of the first cross section (S1) of the arrangement portion perpendicular to the direction of current flow is greater than or equal to the area of the second cross section (S2) of the peripheral portion perpendicular to the direction of current flow . 6. The power converter according to any one of claims 5 to 6 . 6. The area of the first cross section (S1) of the arrangement portion perpendicular to the direction of current flow is larger than the area of the second cross section (S2) of the peripheral portion perpendicular to the direction of current flow. The power conversion device according to any one of the items. Said 1st bus bar and said 2nd bus bar are bus bars which connect the said power converter and the battery (11) which supplies electric power to the said power converter. The power conversion device according to the item. the load is a motor;
During power running operation of the motor, the power supplied from the battery is boosted and supplied to the motor via the power conversion unit, and during regenerative operation of the motor, the power supplied from the motor is stepped down. , a buck-boost unit (27) that supplies the battery,
The first bus bar is an N bus bar connected to the negative electrode of the battery,
9. The power converter according to claim 8, wherein said second bus bar is a P bus bar connected to the positive electrode of said battery .

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