TW202234434A - Inverter unit, motor unit and vehicle an inverter device, comprising: a power module, a capacitor module and plate-shaped positive and negative bus bars - Google Patents

Abstract

An inverter unit according to one aspect of the present invention includes: a power module that converts DC power into AC power; a capacitor module that smoothing the DC voltage supplied from the DC power source; and plate-shaped positive and negative bus bars, which electrically connects the power module and the capacitor module. The positive and negative bus bar extends between the power module and the capacitor module in a state where the plate thickness directions are aligned with each other and overlap in the plate thickness direction.

Description

Inverter unit, motor unit and vehicle

The present invention relates to an inverter unit, a motor unit and a vehicle.

In recent years, the development of inverter units for motor vehicles has flourished. In the inverter unit, a power module and a capacitor module connected to each other by bus bars are provided. In Patent Document 1, a capacitor module and a bus bar connected to the capacitor module are disclosed.

prior art literature Patent Document 1: International Publication No. 2018/170872.

In order to use the power module stably, the value of the surge voltage generated when the switching element is turned off needs to be suppressed to some extent. Conventionally, in order to suppress the value of the surge voltage, the value of the gate resistance is increased, but in this case, there is a problem that the loss in the inverter increases and the conversion efficiency of the inverter decreases.

In view of the above-mentioned circumstances, one object of the present invention is to provide an inverter unit capable of improving conversion efficiency, and a motor unit and a vehicle including such an inverter unit.

An inverter unit according to one aspect of the present invention includes: a power module that converts DC power into AC power; a capacitor module that smoothes the DC voltage supplied from the DC power source; and plate-shaped positive and negative bus bars , which is electrically connected to the power module and the capacitor module. The positive electrode bus bar and the negative electrode bus bar extend between the power module and the capacitor module in a state where the plate thickness directions are aligned with each other and overlap in the plate thickness direction.

A motor unit according to an aspect of the present invention includes the inverter unit described above.

A vehicle according to one aspect of the present invention includes the motor unit described above.

Invention effect According to one aspect of the present invention, an inverter unit capable of improving conversion efficiency, and a motor unit and a vehicle including such an inverter unit can be provided.

Hereinafter, the inverter unit 1 , the motor unit 40 , and the vehicle 41 according to the embodiments of the present invention will be described with reference to the drawings.

In the following description, each part of the inverter unit 1 may be described based on the first direction and the second direction orthogonal to the first direction. In addition, in each drawing, the XYZ coordinate system is appropriately shown as a three-dimensional rectangular coordinate system. The first direction is the Z-axis direction. In addition, the second direction is the X-axis direction.

In this specification, the inverter unit 1 will be described with the +Z direction as the upper side and the −Z direction as the lower side. However, the posture of the inverter unit 1 in actual use is not limited to the vertical direction described in this specification.

FIG. 1 is an explanatory diagram schematically showing a longitudinal section of the inverter unit 1 . FIG. 2 is a circuit block diagram of the motor unit 40 in which the inverter unit 1 is installed. FIG. 3 is an exploded view showing a state in which the bus bar group 9 is disassembled in the inverter unit 1 .

As shown in FIG. 1 , the inverter unit 1 of the present embodiment includes a capacitor module 2 , a power module 3 , a bus bar 9 , a casing 7 , and a refrigerant flow path 8 . In addition, in FIG. 1, the depth direction of a paper surface is the longitudinal direction etc. of the inverter unit 1. As shown in FIG.

The casing 7 accommodates the capacitor module 2 , the power module 3 , and the refrigerant flow path 8 . The components of the inverter unit 1 are stacked and arranged in the vertical direction inside the casing 7 . That is, in this embodiment, the power module 3 and the capacitor module 2 are stacked in the vertical direction (first direction). In addition, the refrigerant flow path 8 is arranged between the power module 3 and the capacitor module 2 .

As shown in FIG. 2 , the inverter unit 1 is mounted on the motor unit 40 . That is, the motor unit 40 has the inverter unit 1 . The motor unit 40 is mounted on a vehicle 41 using a motor as a power source, such as a hybrid vehicle (HEV), a plug-in hybrid vehicle (PHV), and an electric vehicle (EV), and is used as the power source. The vehicle 41 includes a motor unit 40 , a DC power supply 6 for supplying electric power to the motor unit 40 , and wheels (not shown) driven by the motor unit 40 . The DC power source 6 is, for example, a secondary battery or an electric double layer capacitor. In addition, the DC power supply 6 may supply a voltage obtained by boosting the voltage of the secondary battery or the electric double layer capacitor by a boost converter.

The inverter unit 1 is connected between the DC power source 6 and the motor 5 . The inverter unit 1 converts the DC power supplied from the DC power supply 6 into AC power, and supplies power to the motor 5 .

In the present embodiment, the motor 5 is a three-phase motor. The motor 5 may be a four-phase or more multi-phase motor. The motor 5 is connected to the power module 3 of the inverter unit 1 . In addition, the power module 3 may be connected to a generator instead of the motor 5 . In this case, the inverter unit 1 converts the power input from the generator into DC power, and charges the DC power source 6 .

The power module 3 has a plurality of (six in this embodiment) switching elements 30 . The switching element 30 of the present embodiment is an insulated gate bipolar transistor (hereinafter referred to as IGBT: Insulated Gate Bipolar Transistor). The switching element 30 may be a power semiconductor element other than IGBT. For example, the switching element 30 may be a field effect transistor such as a MOSFET.

The power module 3 and the capacitor module 2 respectively constitute a part of the inverter circuit 31 . The inverter circuit 31 is a three-phase inverter composed of six switching elements 30 . That is, the inverter circuit 31 has a three-phase arm composed of two switching elements corresponding to the U-phase, the V-phase, and the W-phase. The midpoint of each bridge arm is connected to the motor 5 .

In addition, one power module 3 is provided in the inverter circuit 31 of the present embodiment, and the power module 3 has six switching elements 30 . However, the inverter circuit 31 may constitute an inverter circuit with three power modules having two switching elements. In addition, the switching element 30 may be configured by connecting a plurality of switching elements in parallel.

The connection terminals 3 p on the positive side of the three arms of the inverter circuit 31 are connected to the positive side terminals 2 p of the capacitor module 2 via the positive bus bar 10 of the bus bar group 9 . Similarly, the connection terminals 3 n on the negative side of the three arms of the inverter circuit 31 are connected to the negative side terminals 2 n of the capacitor module 2 via the negative bus bar 20 of the bus bar group 9 .

The power module 3 has the cooling member 3A shown in FIG. 1 . The cooling member 3A is in contact with the power module 3 . A part of the cooling member 3A is located in the refrigerant flow path 8 . The refrigerant flow path 8 is provided in the frame body 7 or the power module 3 . The refrigerant circulating in the refrigerant flow path 8 cools the power module 3 via the cooling member 3A by contacting the cooling member 3A. The refrigerant flowing in the refrigerant flow path 8 is, for example, an aqueous ethylene glycol solution. The refrigerant can also be water. In addition, the inverter unit 1 may include a mechanism for cooling the capacitor module 2 .

As shown in FIG. 3 , the power module 3 has a plurality of connection terminals 3p and 3n extending in the X-axis direction from a side surface 3f on one side (+X side) in the X-axis direction (second direction). The connection terminals 3p and 3n are in the shape of a plate along a horizontal plane (a plane perpendicular to the first direction).

The plurality of connection terminals 3 p and 3 n of the power module 3 are classified into a positive-side connection terminal (positive-side terminal 3 p ) and a negative-side connection terminal (negative-side terminal 3 n ). In the present embodiment, three positive electrode side terminals 3p and three negative electrode side terminals 3n are provided, respectively. The three positive-side terminals 3p are arranged on the same plane. Likewise, the three negative-side terminals 3n are arranged on the same plane. The negative terminal 3n of the power module 3 is positioned slightly above the positive terminal 3p.

As shown in FIG. 2 , the capacitor module 2 is connected in parallel with the DC power supply 6 and the power module 3 . The capacitor module 2 smoothes the DC voltage supplied to the power module 3 .

As shown in FIG. 1 , the capacitor module 2 includes a capacitor element 2a and a capacitor case 2b in which the capacitor element 2a is accommodated. In the present embodiment, the capacitor module 2 is arranged on the lower side of the refrigerant flow path 8 and is in contact with the refrigerant flow path 8 . The refrigerant flow path 8 cools the capacitor element 2a via the capacitor case 2b, and suppresses the capacitor element 2a from becoming high temperature. Thereby, the reliability of the capacitor module 2 is improved.

As shown in FIG. 3 , the capacitor module 2 has a plurality of connection terminals 2p and 2n extending in the X-axis direction from a side surface 2f on one side (+X side) in the X-axis direction (second direction). The connection terminals 2p and 2n are in the shape of a plate along a horizontal plane (a plane perpendicular to the first direction).

The plurality of connection terminals 2p and 2n of the capacitor module 2 are classified into a positive electrode side connection terminal (hereinafter referred to as a positive electrode side terminal 2p) and a negative electrode side connection terminal (hereinafter referred to as a negative electrode side terminal 2n). In the present embodiment, three positive electrode side terminals 2p and three negative electrode side terminals 2n are provided, respectively. The three positive-side terminals 2p are arranged on the same plane. Similarly, the three negative electrode side terminals 2n are arranged on the same plane. The negative electrode side terminal 2n of the capacitor module 2 is located slightly below the positive electrode side terminal 2p. In addition, the vertical positional relationship between the positive terminal 2p and the negative terminal 2n of the capacitor module 2 and the vertical positional relationship between the positive terminal 3p and the negative terminal 3n of the power module 3 are reversed.

As shown in FIG. 3 , the bus bar group 9 includes a positive electrode bus bar 10 , a negative electrode bus bar 20 , and insulating paper (insulating member) 4 . That is, the inverter unit 1 has the positive electrode bus bar 10 , the negative electrode bus bar 20 , and the insulating paper 4 . The positive electrode bus bar 10 and the negative electrode bus bar 20 are each in the shape of a plate.

The positive bus bar 10 and the negative bus bar 20 electrically connect the power module 3 and the capacitor module 2 . In this embodiment, the power module 3 and the capacitor module 2 are stacked in the up-down direction (first direction). Therefore, the positive bus bar 10 and the negative bus bar 20 extend across each other on one side (+X side) in the X-axis direction (second direction) of the power module 3 and the capacitor module 2 . The positive bus bar 10 connects the positive terminal 3 p of the power module 3 and the positive terminal 2 p of the capacitor module 2 . On the other hand, the negative bus bar 20 connects the negative terminal 3 n of the power module 3 and the negative terminal 2 n of the capacitor module 2 .

The positive bus bar 10 includes: a positive main plate part 15 extending in the vertical direction; a positive upper plate part 16 connected to the upper end of the positive main plate part 15 ; and a positive lower plate part connected to the lower end of the positive main plate part 15 17. Similarly, the negative electrode bus bar 20 includes: a negative electrode main plate part 25 extending in the vertical direction; a negative electrode upper plate part 26 connected to the upper end of the negative electrode main plate part 25 ; and a negative electrode connected to the lower end of the negative electrode main plate part 25 Lower plate portion 27 .

The positive electrode main plate portion 15 and the negative main plate portion 25 extend parallel to each other in a state in which the plate thickness directions are aligned with each other and overlapped in the plate thickness direction. The positive main plate portion 15 and the negative main plate portion 25 are arranged along side surfaces 3 f and 2 f on one side (+X side) in the X-axis direction (second direction) of the power module 3 and the capacitor module 2 . In addition, the negative electrode master plate portion 25 is arranged on one side (+X side) of the positive electrode master plate portion 15 in the X-axis direction (second direction).

The plate thickness directions of the positive electrode upper plate portion 16 and the negative electrode upper plate portion 26 are aligned with each other. The positive electrode upper plate portion 16 and the negative electrode upper plate portion 26 extend along a horizontal plane (a plane perpendicular to the first direction). That is, the positive electrode upper plate portion 16 and the negative electrode upper plate portion 26 extend parallel to each other.

The positive electrode upper plate portion 16 extends from the upper end of the positive electrode main plate portion 15 to the other side (−X side) in the X-axis direction (second direction). Similarly, the negative electrode upper plate portion 26 extends from the upper end of the negative electrode main plate portion 25 to the other side (−X side) in the X-axis direction (second direction). The negative electrode upper plate portion 26 is arranged above the positive electrode upper plate portion 16 .

The positive electrode lower plate portion 17 and the negative electrode lower plate portion 27 have their plate thickness directions aligned with each other. The positive electrode lower plate portion 17 and the negative electrode lower plate portion 27 extend along a horizontal plane (a plane perpendicular to the first direction). That is, the positive electrode lower plate portion 17 and the negative electrode lower plate portion 27 extend parallel to each other.

The positive electrode lower plate portion 17 extends from the lower end of the positive electrode main plate portion 15 to the other side (−X side) in the X-axis direction (second direction). Similarly, the negative electrode lower plate portion 27 extends from the lower end of the negative electrode main plate portion 25 to the other side (−X side) in the X-axis direction (second direction). The negative electrode lower plate portion 27 is arranged below the positive electrode lower plate portion 17 .

According to the present embodiment, the positive electrode bus bar 10 and the negative electrode bus bar 20 extend between the power module 3 and the capacitor module 2 in a state in which the plate thickness directions coincide with each other and overlap in the plate thickness direction.

Here, the power module 3 increases the parasitic inductance to an extent that cannot be ignored in order to handle large power. According to the present embodiment, the positive electrode bus bar 10 and the negative electrode bus bar 20 are arranged to overlap in the thickness direction. In addition, the positive electrode bus bar 10 and the negative electrode bus bar 20 flow currents of the same current value in opposite directions to each other. Therefore, the mutual inductance generated by the current flowing through the positive electrode bus bar 10 and the current flowing through the negative electrode bus bar 20 functions to cancel the self-inductance, and the effective parasitic inductance can be reduced.

The larger the overlapping area of the positive electrode bus bar 10 and the negative electrode bus bar 20 viewed from the thickness direction, the smaller the parasitic inductance. Preferably, the positive bus bar 10 and the negative bus bar 20 overlap by more than 90% of the width dimension, and more preferably, overlap by more than 95%. In addition, the positive bus bar 10 and the negative bus bar 20 preferably overlap by more than 90% of the length dimension, and more preferably overlap by more than 95%. By adjusting the overlapping amount of the positive electrode bus bar 10 and the negative electrode bus bar 20 in this way, the effect of suppressing parasitic inductance can be sufficiently obtained.

In addition, the closer the positive electrode bus bar 10 and the negative electrode bus bar 20 are arranged in the thickness direction, the smaller the parasitic inductance is. Preferably, the size of the gap along the thickness direction between the positive electrode bus bar 10 and the negative electrode bus bar 20 is smaller than the plate thicknesses of the positive electrode bus bar 10 and the negative electrode bus bar 20 . By arranging the positive electrode bus bar 10 and the negative electrode bus bar 20 close to each other in this way, the effect of suppressing parasitic inductance can be sufficiently obtained. In the present embodiment, the gap between the positive electrode bus bar 10 and the negative electrode bus bar 20 is substantially equal to the thickness of the insulating paper 4 arranged in the gap.

In general, for the switching element 30 such as an IGBT, the maximum rated voltage is determined in advance, and it is required to drive the switching element 30 with a voltage lower than the maximum rated voltage. That is, the power module 3 is designed so that the voltage applied to the switching element 30 is less than the maximum rated voltage. The maximum voltage supplied to the switching element 30 is a surge voltage generated when the switching element 30 is turned off. It is known that the value of the surge voltage can be reduced by increasing the value of the gate resistance. Therefore, the power module 3 is provided with a gate resistor having a sufficiently large resistance value such that the value of the surge voltage does not exceed the maximum rated voltage of the switching element 30 . Thereby, the value of the surge voltage can be suppressed, but on the other hand, the resistance value of the entire inverter circuit 31 also increases, and there is a problem that the conversion efficiency of the inverter circuit 31 decreases.

In addition, it is known that the value of the surge voltage also has a correlation with the parasitic inductance. That is, the value of the surge voltage becomes larger as the parasitic inductance becomes larger. According to the present embodiment, as described above, since the parasitic inductance is reduced, the value of the surge voltage can be suppressed. As a result, even if the value of the gate resistance is reduced, the value of the surge voltage can be suppressed from exceeding the maximum rated voltage. According to the present embodiment, the conversion efficiency of the inverter circuit 31 is improved, and the inverter unit 1 can be provided with low power consumption.

As shown in FIG. 1 , the positive upper plate portion 16 of the positive electrode bus bar 10 is provided with an upper positive positive connection portion (connecting portion) 11 connected to the power module 3 , and the positive lower plate portion 17 is provided with a positive electrode connected to the capacitor module 2 . The lower positive electrode connection portion (connection portion) 12 . Similarly, the upper negative plate portion 26 of the negative electrode bus bar 20 is provided with an upper negative electrode connection portion (connection portion) 21 connected to the power module 3 , and the negative electrode lower plate portion 27 is provided with a lower negative electrode connection connected to the capacitor module 2 . part (connection part) 22 . That is, the positive electrode bus bar 10 and the negative electrode bus bar 20 respectively have connection parts 11 and 21 connected to the power module 3 and connection parts 12 and 22 connected to the capacitor module 2 .

As shown in FIG. 3 , the positions of the positive electrode side terminal 3p and the negative electrode side terminal 3n of the power module 3 in the vertical direction are shifted from each other. In addition, the vertical positions of the plurality of positive electrode side terminals 3p coincide with each other, and the vertical direction positions of the plurality of negative electrode side terminals 3n coincide with each other. The upper positive electrode connection portion 11 of the positive electrode bus bar 10 is connected across the plurality of positive electrode side terminals 3p. Similarly, the upper negative electrode connecting portion 21 of the negative electrode bus bar 20 is connected across the plurality of negative electrode side terminals 3n.

The vertical positions of the positive electrode side terminal 2p and the negative electrode side terminal 2n of the capacitor module 2 are shifted from each other. In addition, the vertical positions of the plurality of positive electrode side terminals 2p coincide with each other, and the vertical direction positions of the plurality of negative electrode side terminals 2n coincide with each other. The lower positive electrode connecting portion 12 of the positive electrode bus bar 10 is connected across the plurality of positive electrode side terminals 2p. Similarly, the lower negative electrode connecting portion 22 of the negative electrode bus bar 20 is connected across the plurality of negative electrode side terminals 2n.

FIG. 4 is an enlarged schematic view of the upper positive electrode connection portion 11 and the upper negative electrode connection portion 21 .

The upper positive electrode connecting portion 11 of the positive electrode bus bar 10 and the positive electrode side terminal 3p of the power module 3 are arranged to face each other in the up-down direction, and are connected to each other by welding through the welding portion W. Similarly, the upper negative electrode connecting portion 21 of the negative electrode bus bar 20 and the negative electrode side terminal 3n of the power module 3 are arranged to face each other in the up-down direction, and are welded to each other via the welding portion W.

According to the present embodiment, the upper positive electrode connection portion 11 and the upper negative electrode connection portion 21 are stacked in the up-down direction, and the front-end positions thereof coincide with each other. That is, the positive electrode bus bar 10 and the negative electrode bus bar 20 also overlap each other in the plate thickness direction in the connection parts 11 and 21 connected to the power module 3 , and parasitic inductance can also be suppressed in the connection parts 11 and 21 .

FIG. 5 is an enlarged schematic view of the lower positive electrode connecting portion 12 and the lower negative electrode connecting portion 22 .

The lower positive electrode connecting portion 12 of the positive electrode bus bar 10 and the positive electrode side terminal 2p of the capacitor module 2 are arranged to face each other in the up-down direction, and are connected to each other by welding through the welding portion W. Similarly, the lower negative electrode connecting portion 22 of the negative electrode bus bar 20 and the negative electrode side terminal 2n of the capacitor module 2 are arranged to face each other in the up-down direction, and are welded to each other via the welding portion W.

According to the present embodiment, the lower positive electrode connection portion 12 and the lower negative electrode connection portion 22 are stacked in the up-down direction, and the distal end positions are aligned with each other. That is, the positive electrode bus bar 10 and the negative electrode bus bar 20 overlap each other in the plate thickness direction at the connection parts 12 and 22 with the capacitor module 2 , and parasitic inductance can also be suppressed in the connection parts 12 and 22 .

In this embodiment, the positive bus bar 10 and the negative bus bar 20 overlap each other in the connection parts 11 and 21 connected to the power module 3 and the connection parts 12 and 22 connected to the capacitor module 2 . Thereby, the parasitic inductance as a whole can be further reduced. However, as long as the positive electrode bus bar 10 and the negative electrode bus bar 20 overlap at the connection portion with either of the power module 3 and the capacitor module 2, a certain effect can be obtained in suppressing parasitic inductance. That is, a certain effect can be obtained as long as the positive bus bar 10 and the negative bus bar 20 overlap each other in the thickness direction at the connection portion connected to at least one of the power module 3 and the capacitor module 2 .

According to this embodiment, the positive electrode bus bar 10 and the negative electrode bus bar 20 are connected to the connection terminals 2p, 3p, 2n, 3n extending from at least one of the power module 3 and the capacitor module 2 at the connection portions 11 , 12 , 21 , and 22 Solder connection. Welding is a connecting method that can suppress the enlargement of the thickness direction dimension of the joint portion. According to the present embodiment, the positive electrode bus bar 10 and the negative electrode bus bar 20 are less likely to increase in size in the thickness direction at the connecting portions 11 , 12 , 21 , and 22 , and can be arranged close to each other in the thickness direction. Thereby, parasitic inductance in the connection parts 11 , 12 , 21 , and 22 can be effectively suppressed.

As shown in FIG. 3 , the insulating paper 4 is sandwiched between the positive electrode bus bar 10 and the negative electrode bus bar 20 . The insulating paper 4 is disposed between the main plate portions 15 and 25 of the positive electrode bus bar 10 and the negative electrode bus bar 20 , between the upper plate portions 16 and 26 and between the lower plate portions 17 and 27 . One sheet of insulating paper 4 may be arranged at each of these three places, or one sheet of insulating paper 4 may be bent so as to span these three places. Thereby, even if the positive electrode bus bar 10 and the negative electrode bus bar 20 are brought close to each other, the insulation between the positive electrode bus bar 10 and the negative electrode bus bar 20 can be ensured. As a result, the reliability of the inverter unit 1 can be improved.

In addition, the member sandwiched between the positive electrode bus bar 10 and the negative electrode bus bar 20 may be an insulating member (insulating member), and its material is not limited, for example, an insulating resin member molded into a plate shape or a sheet shape may be used. .

<Variation 1> FIG. 6 is an enlarged schematic view of the connection portion 122 of the negative electrode bus bar 120 of Modification 1 that can be employed in the above-described embodiment.

In addition, the same code|symbol is attached|subjected to the component of the same form as the said embodiment, and the description is abbreviate|omitted.

The negative bus bar 120 of the present modification is mainly different in the structure of the connection portion 122 . In addition, in this modification, the connection part 122 of the negative bus bar 120 and the capacitor module 2 will be described. However, the connection portion between the negative bus bar 120 and the power module 3 and the connection portion between the positive bus bar 110 and at least one of the capacitor module 2 and the power module 3 can also adopt the same structure.

As in the above-described embodiment, the positive electrode bus bar 110 and the positive electrode side terminal 102p of the capacitor module 2 are arranged to face each other in the vertical direction. Similarly, the negative electrode bus bar 120 and the negative electrode side terminal 102n of the capacitor module are arranged to face each other in the up-down direction. The positive electrode bus bar 110 and the positive electrode side terminal 102p are arranged slightly above the negative electrode bus bar 120 and the negative electrode side terminal 102n. Similar to the above-described embodiment, the positive bus bar 110 and the negative bus bar 120 of the present modification overlap each other in the plate thickness direction at the connecting portion 122 , so that parasitic inductance in the connecting portion 122 can be suppressed.

The connecting portion 122 of the negative bus bar 120 is provided with a fastening hole 129 penetrating in the thickness direction. Similarly, the negative electrode-side terminal 102n is provided with a fastening hole 102h penetrating in the thickness direction. The bolts 151 pass through these fastening holes 129, 102h. The connection portion 122 of the negative bus bar 120 is fastened to the negative terminal 102n by bolts 151 and nuts 152 .

On the other hand, the positive electrode bus bar 110 is provided with an escape hole 118 . The escape hole 118 overlaps with the negative bus bar 120 and the fastening holes 129 and 102h of the negative terminal 102n when viewed from the up-down direction. Inside the escape hole 118 , the shaft portion of the bolt 151 and the nut 152 are arranged. That is, the positive electrode bus bar 110 is provided with the escape hole 118 for avoiding the bolt 151 and the nut 152 used for fastening the negative electrode bus bar 120 . According to this modification, since the positive bus bar 110 avoids interference with the nut 152 in the escape hole 118 , the positive bus bar 110 can be arranged close to the negative bus bar 120 , and parasitic inductance can be effectively suppressed.

In this modification, the case where the bolt 151 is inserted from the lower side of the positive electrode bus bar 110 and the nut 152 is arranged on the upper side of the positive electrode bus bar 110 has been described. However, the bolt 151 may be inserted from the upper side of the positive bus bar 110 . In this case, the escape hole 118 only avoids interference with the bolt 151 .

In addition, in the case where the connection portion of the positive electrode bus bar 110 has the same structure, it is preferable to provide an escape hole in the negative electrode bus bar 120 . That is, it is preferable that one of the positive electrode bus bar 110 and the negative electrode bus bar 120 is provided with an escape hole that avoids a bolt or a nut for fastening the other.

According to this modification, the fastening hole 129 of the negative electrode bus bar 120 overlaps with the escape hole 118 of the positive electrode bus bar 110 . Therefore, the states of the currents flowing through the negative electrode bus bar 120 and the positive electrode bus bar 110 can be made close to each other around the fastening hole 129 and around the escape hole 118 . Thereby, parasitic inductance can be effectively suppressed.

<Variation 2> FIG. 7 is an explanatory diagram schematically showing a longitudinal cross-section of the inverter unit 201 of Modification 2. FIG. The inverter unit 201 of this modification is different from the above-mentioned embodiment mainly in the arrangement of the power module 3 and the capacitor module 2 , and accordingly, the structure of the bus bar 209 is also different.

In addition, the same code|symbol is attached|subjected to the component of the same form as the said embodiment, and the description is abbreviate|omitted.

The inverter unit 201 of the present modification example includes a capacitor module 2 , a power module 3 , a bus bar 209 , a refrigerant flow path 8 , and a casing 207 that accommodates these, as in the above-described embodiment.

Inside the casing 207 , the power module 3 and the capacitor module 2 are arranged opposite to each other in the X-axis direction (second direction). In addition, the refrigerant flow paths 8 are stacked and arranged on the lower side of the power module 3 . The bus bar group 209 extends along the X-axis direction (the second direction), and connects the power module 3 and the capacitor module 2 .

The bus bar group 209 has a positive bus bar 210 , a negative bus bar 220 and insulating paper 204 . That is, the inverter unit 201 has the positive electrode bus bar 210 , the negative electrode bus bar 220 , and the insulating paper 204 . The positive electrode bus bar 210 and the negative electrode bus bar 220 are respectively plate-shaped. The positive electrode bus bar 210 and the negative electrode bus bar 220 extend between the power module 3 and the capacitor module 2 in a state in which the plate thickness directions coincide with each other and overlap in the plate thickness direction. In addition, the insulating paper 204 is sandwiched between the positive electrode bus bar 210 and the negative electrode bus bar 220 .

In this modification, the power module 3 and the capacitor module 2 are arranged side by side in the X-axis direction (second direction). Therefore, the positive bus bar 210 and the negative bus bar 220 are arranged across the opposing surfaces of the power module 3 and the capacitor module 2 .

The embodiments of the present invention and their modifications have been described above, but the respective configurations and their combinations in the embodiments and modifications are merely examples, and additions and omissions of configurations are possible without departing from the gist of the present invention. , replacements and other changes. In addition, this invention is not limited to embodiment and modification.

The positive bus bar may be an integral member with either the positive terminal of the power module or the positive terminal of the capacitor module. Similarly, the negative bus bar may be an integral member with either the negative terminal of the power module or the negative terminal of the capacitor module.

1,201: Inverter unit 2: Capacitor module 2a: Capacitor element 2b: Capacitor housing 2f: side 2n, 2p, 3n, 3p: connection terminals 3: Power Module 3A: Cooling parts 3f: side 4,204: Insulating paper (insulating parts) 5: Motor 6: DC power supply 7,207: Frame 8: Refrigerant flow path 9,209: Busbar set 10, 110, 210: Positive busbar 11, 12, 21, 22, 122: Connections 15: Positive motherboard part 16: Positive upper plate 17: Positive lower plate 20,120,220: Negative busbar 25: Negative main board part 26: Negative upper plate 27: Negative lower plate 30: Switching element 31: Inverter circuit 40: Motor unit 41: Vehicles 102h, 129 Fastening holes 102n: Negative side terminal 102p: Positive side terminal 118: Escape hole 151: Bolts 152: Nut W: Welding Department

FIG. 1 is an explanatory diagram schematically showing a longitudinal cross-section of an inverter unit according to an embodiment. 2 is a circuit block diagram of a motor unit to which the inverter unit of one embodiment is installed. FIG. 3 is an exploded view of an inverter unit according to an embodiment. FIG. 4 is an enlarged schematic view of a connection portion between a bus bar and a power module according to an embodiment. FIG. 5 is an enlarged schematic view of a connection portion between a bus bar and a capacitor module according to an embodiment. 6 is an enlarged schematic view of a connection portion between the bus bar and the capacitor module in Modification 1. FIG. FIG. 7 is an explanatory diagram schematically showing a longitudinal cross-section of an inverter unit according to Modification 2. FIG.

1: Inverter unit

2: Capacitor module

2a: Capacitor element

2b: Capacitor housing

2f: side

3: Power Module

3A: Cooling parts

3f: side

4: Insulating paper (insulating parts)

7: Frame

8: Refrigerant flow path

9: Bus group

10: Positive bus bar

11, 12, 21, 22: Connections

15: Positive motherboard part

16: Positive upper plate

17: Positive lower plate

20: Negative busbar

25: Negative main board part

26: Negative upper plate

27: Negative lower plate

Claims (11)

An inverter unit having: A power module that converts DC power to AC power; a capacitor module that smoothes a DC voltage supplied from a DC power source; and Plate-shaped positive and negative bus bars, the positive and negative bus bars electrically connect the power module and the capacitor module, The positive electrode bus bar and the negative electrode bus bar extend between the power module and the capacitor module in a state where the plate thickness directions are aligned with each other and overlap in the plate thickness direction. The inverter unit of claim 1, wherein, The positive bus bar and the negative bus bar have a connection portion connected to at least one of the power module and the capacitor module, The positive electrode bus bar and the negative electrode bus bar also overlap each other in the plate thickness direction at the connection portion. The inverter unit of claim 2, wherein, The positive bus bar and the negative bus bar are welded and connected to at least one of the connection terminals extending from the power module and the capacitor module at the connection portion. The inverter unit of claim 2, wherein, The positive bus bar and the negative bus bar are fastened to at least one of the connection terminals extending from the power module and the capacitor module at the connecting portion through bolts and nuts, One of the positive electrode bus bar and the negative electrode bus bar is provided with an escape hole for avoiding the bolt or the nut used for fastening the other. The inverter unit of any one of claims 1 to 4, wherein, An insulating member is sandwiched between the positive electrode bus bar and the negative electrode bus bar. The inverter unit of any one of claims 1 to 4, wherein, The power module and the capacitor module are stacked in the first direction, The positive electrode bus bar and the negative electrode bus bar extend over each other on one side of the power module and the capacitor module on one side in a second direction orthogonal to the first direction. The inverter unit of any one of claims 1 to 4, wherein, The power module and the capacitor module are arranged opposite to each other, and the positive bus bar and the negative bus bar are arranged across the opposite surfaces of the power module and the capacitor module. The inverter unit of any one of claims 1 to 4, wherein, The power module has an insulated gate bipolar transistor. The inverter unit of any one of claims 1 to 4, wherein, The power module has a field effect transistor. . A motor unit including the inverter unit according to any one of claims 1 to 9. A vehicle including the motor unit according to claim 10 .

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