Power conversion device

Abstract

A power conversion device includes a voltage conversion circuit that converts a direct-current voltage, an inverter circuit that converts the direct-current voltage into an alternating-current voltage, a negative bus that is commonly connected to the voltage conversion circuit and the inverter circuit, a first positive bus that is connected to the voltage conversion circuit, a second positive bus that is connected to the inverter circuit, a housing that accommodates the voltage conversion circuit and the inverter circuit, and a first heat dissipation member that is provided in the housing. The first positive bus and the second positive bus are provided in a stacked manner with the negative bus and are electrically insulated from each other. The first positive bus and the second positive bus are opposed to the first heat dissipation member via an insulating member. At least one of the first positive bus and the second positive bus is in thermal contact with the first heat dissipation member via the insulating member and a first heat conduction member.

Description

Technical Field

[0001] This invention relates to a power conversion device. Background Technology

[0002] In power conversion devices, which include voltage conversion circuits that transform DC voltage and inverter circuits that transform the transformed DC voltage into AC voltage, busbars are installed to form positive and negative terminals. Due to the large current flowing through these busbars, they generate significant heat, greatly affecting capacitors and other components installed within the power conversion device for purposes such as noise reduction. Therefore, it is necessary to limit the current flowing through the busbars within a range that does not exceed the heat resistance temperature of the capacitors, which limits the output performance of the power conversion device.

[0003] Patent Document 1 discloses a power conversion device comprising: an inverter circuit section for performing DC / AC power conversion; a converter circuit section for boosting voltage from an external battery and outputting it to the inverter circuit section; and a smoothing capacitor package comprising: a capacitor element; a negative bus connected to both the negative side of the inverter circuit section and the negative side of the converter circuit section; a first positive bus connected to the positive side of the inverter circuit section; and a second positive bus connected to the positive side of the battery side of the converter circuit section, wherein the first positive bus is opposite to one main surface of the negative bus, and the second positive bus is disposed at a position opposite to the other main surface of the negative bus. Existing technical documents Patent documents

[0004] Patent Document 1: Japanese Patent Application Publication No. 2014-176237 Summary of the Invention The problem the invention aims to solve

[0005] In the power conversion device described in Patent Document 1, the heat of the busbar cannot be reduced, which limits the output performance of the power conversion device. Technical means to solve the problem

[0006] The power conversion device according to the present invention comprises: a voltage conversion circuit that converts a first DC voltage to a second DC voltage; an inverter circuit that converts the second DC voltage to an AC voltage; a negative bus that is connected to both the voltage conversion circuit and the inverter circuit; a first positive bus that is connected to the voltage conversion circuit; a second positive bus that is connected to the inverter circuit; a housing that accommodates the voltage conversion circuit and the inverter circuit; and a first heat dissipation member disposed in the housing, wherein the first positive bus and the second positive bus are stacked on top of the negative bus and electrically insulated from each other, the first positive bus and the second positive bus are opposite to the first heat dissipation member through an insulating member, and at least one of the first positive bus and the second positive bus is in thermal contact with the first heat dissipation member via the insulating member and the first heat conduction member. The effects of the invention

[0007] According to the present invention, the heat of the busbar can be reduced and the output performance of the power conversion device can be improved. Attached Figure Description

[0008] Figure 1 This is an exploded 3D view of a power conversion device. Figure 2 This is a circuit diagram of a power conversion device. Figure 3 This is an exploded perspective view of the main parts of the power conversion device. Figure 4 (A) and (B) are cross-sectional views of the power conversion device. Figure 5 (A) and (B) are cross-sectional views representing variations 1 and 2 of the power conversion device. Figure 6 (A) and (B) are cross-sectional views representing variations 3 and 4 of the power conversion device. Figure 7 This is a perspective view of a modified example 5 of a power conversion device. Figure 8 This is a perspective view of a modified example 6 of a power conversion device. Detailed Implementation

[0009] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. The following description and drawings are examples for illustrating the present invention; appropriate omissions and simplifications have been made to clarify the description. The present invention may also be implemented in various other ways. Unless otherwise specified, the constituent elements may be singular or plural.

[0010] To facilitate understanding of the present invention, the positions, sizes, shapes, and extents of the constituent elements shown in the accompanying drawings may not represent their actual positions, sizes, shapes, or extents. Therefore, the present invention is not limited to the positions, sizes, shapes, and extents disclosed in the accompanying drawings.

[0011] When there are multiple constituent elements with the same or identical functions, different subscripts are sometimes added to the same symbols for explanation. However, when it is not necessary to distinguish these multiple constituent elements, the symbols are sometimes omitted for explanation.

[0012] Figure 1 This is an exploded perspective view of the power conversion device 1000 of this embodiment. The power conversion device 1000 includes a semiconductor module 100, a capacitor 200, and a reactor 300. The semiconductor module 100, capacitor 200, and reactor 300 are housed in a housing 400. The housing 400 is divided into a first receiving space 401 and a second receiving space 402 by a first heat dissipation member 410 integrally formed with the housing 400. The semiconductor module 100 and reactor 300 are housed in the first receiving space 401, and the capacitor 200 is housed in the second receiving space 402. A cooling flow path is formed within the housing 400, through which refrigerant flows in and out via an inlet 403. Although not shown in the figure, the refrigerant flows through the cooling flow path within the housing 400 and within the cooling flow path provided in the semiconductor module 100. The refrigerant flowing through the cooling flow path cools not only the semiconductor module 100 but also the housing 400 and the first heat dissipation member 410.

[0013] A molded busbar 500 is provided on the upper surface of the semiconductor module 100 and reactor 300 housed in the first housing space 401 and the capacitor 200 housed in the second housing space 402, opposite to the bottom surface of the first housing space 401 and the second housing space 402. The molded busbar 500 is formed by sealing the first positive busbar 510, the second positive busbar 520 and the negative busbar 530 with insulating resin or the like for the purpose of electrical insulation between each busbar and other conductive components. The first positive busbar 510, the second positive busbar 520 and the negative busbar 530 are flat wiring members that form electrical wiring, for example, made of conductive materials such as copper. A first heat-conducting member 600 is coated on the upper surface of the first heat-dissipating member 410, and the molded busbar 500 is in thermal contact with the first heat-dissipating member 410 via the first heat-conducting member 600.

[0014] The first positive bus 510 and negative bus 530 of the molded bus 500 are connected to a battery (not shown) via terminals P and N, respectively, to supply DC voltage from the battery. The semiconductor module 100 is also provided with four modules: one for the voltage conversion circuit 1100 and three for the inverter circuit 1200 (see reference). Figure 2 ).

[0015] The semiconductor module 100 used in the voltage conversion circuit 1100 boosts and converts the DC voltage supplied via the molded bus 500 into a DC voltage by switching the semiconductor elements sealed within the semiconductor module 100. The converted DC voltage is output to one of the output buses 700 and input to the semiconductor module 100 used as an inverter circuit 1200 via the molded bus 500.

[0016] The semiconductor module 100 used in the inverter circuit 1200 converts the DC voltage supplied by the voltage conversion circuit 1100 into AC current via the molded bus 500 by switching semiconductor elements sealed within the semiconductor module 100. The converted AC current is output from the output bus 700. The output AC current is supplied to a motor (not shown) and drives the motor. A current sensor 710 is disposed near the output bus 700.

[0017] The first accommodating space 401 and the second accommodating space 402 are enclosed by the substrate 800. The substrate 800 is fixed to the housing 400 by screws or the like around its four corners. A circuit board 900 is provided on the substrate 800. A control circuit 1300 (see reference) for a drive control voltage conversion circuit 1100 and an inverter circuit 1200 is mounted on the circuit board 900. Figure 2 The semiconductor module 100 has a control terminal that receives a drive signal G2 from the control circuit 1300. A connection line to the control terminal is connected to the control circuit 1300 on the circuit board 900 via a hole provided on the substrate 800. Furthermore, electronic components input / output torque commands and other command signals to an external control device via a connector 910.

[0018] The housing 400 includes a cover 490 and houses the substrate 800 and the circuit board 900. A sealing ring or liquid sealant is provided between the housing 400 and the cover 490 to ensure the internal airtightness of the power conversion device 1000. The housing 400, the first heat dissipation member 410, the cover 490, and the substrate 800 are made of a material with high thermal conductivity, such as aluminum.

[0019] Figure 2 This is the circuit diagram of the power conversion device 1000. The power conversion device 1000 includes a voltage conversion circuit 1100, an inverter circuit 1200, and a control circuit 1300. The voltage conversion circuit 1100 and the inverter circuit 1200 are configured with semiconductor modules 100a, 100b, 100c, and 100d, each containing built-in semiconductor elements. The semiconductor modules 100a, 100b, 100c, and 100d switch the semiconductor elements on / off via drive signals G1 and G2 from the control circuit 1300 on the circuit board 900. The control circuit 1300 controls the switching operations of the semiconductor modules 100a, 100b, 100c, and 100d according to command signals from an external control device (not shown).

[0020] In the voltage conversion circuit 1100, DC voltage is input from the battery via terminals P and N to the area between the first positive bus 510 and the negative bus 530. Filter capacitors C3 and C4 are provided between the first positive bus 510 and ground, and between the negative bus 530 and ground. These capacitors C3 and C4 are installed to reduce common-mode noise flowing through the positive and negative terminals. Specifically, noise from the voltage conversion circuit 1100 and the inverter circuit 1200 is bypassed to ground, preventing common-mode noise from being conducted to the battery. Furthermore, common-mode noise from the battery is prevented from being conducted to the voltage conversion circuit 1100 and the inverter circuit 1200.

[0021] The voltage conversion circuit 1100 includes a semiconductor module 100a, a reactor 300, and a capacitor C1. In the semiconductor module 100a, semiconductor elements T1 and T2 are connected in series, and diodes D1 and D2 are connected in parallel between the collector and emitter of semiconductor elements T1 and T2, respectively. The collector side of semiconductor element T1 is connected to the second positive bus 520, and its emitter side is connected to one end of the reactor 300 and the collector side of semiconductor element T2. The other end of the reactor 300 is connected to the first positive bus 510, and the emitter side of semiconductor element T2 is connected to the negative bus 530. A capacitor C1 is connected between the first positive bus 510 and the negative bus 530 at the other end of the reactor 300. The negative bus 530 is shared by the voltage conversion circuit 1100 and the inverter circuit 1200.

[0022] The voltage conversion circuit 1100 controls the on / off state of semiconductor elements T1 and T2 via a drive signal G1 from the control circuit 1300. Thus, the voltage conversion circuit 1100 performs a boost function, converting the DC voltage from the battery to a higher DC voltage value and outputting it to the inverter circuit 1200. Additionally, during regenerative braking of the motor, it performs a buck function, converting the DC voltage output from the inverter circuit 1200 to the voltage conversion circuit 1100 to a lower DC voltage and outputting it to the battery.

[0023] The inverter circuit 1200 includes semiconductor modules 100b, 100c, and 100d, and capacitor C2. In semiconductor module 100b, semiconductor elements T3 and T4 are connected in series, and diodes D3 and D4 are connected in parallel between the collector and emitter of semiconductor elements T3 and T4, respectively. In semiconductor module 100c, semiconductor elements T5 and T6 are connected in series, and diodes D5 and D6 are connected in parallel between the collector and emitter of semiconductor elements T5 and T6, respectively. In semiconductor module 100d, semiconductor elements T7 and T8 are connected in series, and diodes D7 and D8 are connected in parallel between the collector and emitter of semiconductor elements T7 and T8, respectively.

[0024] The collector sides of semiconductor elements T3, T5, and T7 are connected to the second positive bus 520, and the emitter sides of semiconductor elements T4, T6, and T8 are connected to the negative bus 530. A smoothing capacitor C2 is connected between the second positive bus 520 and the negative bus 530. The connection point between the emitter sides of semiconductor elements T3, T5, and T7 and the collector sides of semiconductor elements T4, T6, and T8 is connected to a motor (not shown) via the output bus 700.

[0025] The inverter circuit 1200 controls the switching on / off of semiconductor elements T3 to T8 based on the DC voltage output from the voltage conversion circuit 1100 via the drive signal G2 from the control circuit 1300. This drives the motor by making the phase of the AC current flowing through it 120° different in each of the U, V, and W phases and outputting three-phase AC power to the motor.

[0026] Figure 3 This is an exploded perspective view of the main components of the power conversion device 1000, showing the semiconductor module 100, capacitor 200, and molded busbar 500. The figure shows the molded busbar 500 with the insulating resin seal removed. An example of capacitor 200 including capacitors C1 and C2 is shown, but it may also include capacitors C1, C2, C3, and C4. The reactor 300 is omitted from the illustration.

[0027] The molded busbar 500 includes a first positive busbar 510, a second positive busbar 520, and a negative busbar 530. The first positive busbar 510, the second positive busbar 520, and the negative busbar 530 are, for example, flat wiring components formed from a conductive material such as copper. The first positive busbar 510 and the second positive busbar 520 are arranged side-by-side on the upper surfaces of semiconductor modules 100a, 100b, 100c, 100d, and capacitor 200. The first positive busbar 510 is arranged in an insulated manner on the upper surfaces of semiconductor module 100a and capacitor C1, and the second positive busbar 520 is arranged in an insulated manner on the upper surfaces of semiconductor modules 100b, 100c, 100d, and capacitor C2. The negative bus 530 is stacked on the opposite side of the semiconductor module 100 and the capacitor 200, separated by the first positive bus 510 and the second positive bus 520, and is on the first positive bus 510 and the second positive bus 520.

[0028] The first positive bus 510 is connected to the emitter terminal of the semiconductor element T1 protruding from the semiconductor module 100a via the reactor 300. The negative bus 530 is connected to the emitter terminal of the semiconductor element T2 protruding from the semiconductor module 100a.

[0029] The collector terminals of semiconductor elements T3, T5, and T7 protruding from semiconductor modules 100b, 100c, and 100d are connected to the second positive bus 520. The emitter terminals of semiconductor elements T4, T6, and T8 protruding from semiconductor modules 100b, 100c, and 100d are connected to the negative bus 530.

[0030] The positive and negative terminals of capacitor C1 are connected to the first positive bus 510 and the negative bus 530, respectively, and the positive and negative terminals of capacitor C2 are connected to the second positive bus 520 and the negative bus 530, respectively.

[0031] Furthermore, although the illustration is omitted, the control terminals protrude from the gates of semiconductor elements T1 to T8 of the semiconductor module 100 and are connected to the control circuit 1300 on the circuit board 900. Additionally, the output terminals protrude from the connection points between the emitter sides of semiconductor elements T3, T5, and T7 and the collector sides of semiconductor elements T4, T6, and T8 of the semiconductor module 100 and are connected to the output bus 700.

[0032] For example, when using an electric motor as the drive source for a vehicle, as shown in reference... Figure 2 As explained, the power conversion device 1000 uses a voltage conversion circuit 1100 and an inverter circuit 1200. In this case, the positive bus is divided into a first positive bus 510 and a second positive bus 520. As a result, as... Figure 3As shown, the first positive busbar 510, the second positive busbar 520, and the negative busbar 530, which are formed into flat plates, have different areas, increasing in the order of the first positive busbar 510, the second positive busbar 520, and the negative busbar 530. Assuming that the thickness of each busbar is the same, the smaller the area, the greater the resistance. Therefore, when each busbar is energized, the heat generation increases in the order of decreasing resistance, i.e., in the order of the first positive busbar 510, the second positive busbar 520, and the negative busbar 530. In this embodiment, as described below, the busbars are configured according to their heat generation to comprehensively reduce the heat of the busbars.

[0033] In addition, a capacitor 200 is electrically connected to the power conversion device 1000 for purposes such as supplying charge to semiconductor elements and removing noise. The capacitor 200 is affected by heat from the bus. Typically, because the heat resistance temperature of the capacitor element inside the capacitor 200 is low, it is necessary to limit the current flowing through the bus within a range that does not exceed the heat resistance temperature of the capacitor element, which limits the output performance of the power conversion device 1000. In this embodiment, by reducing the heat of the bus, it is possible to increase the current flowing through the bus and improve the output performance of the power conversion device 1000.

[0034] Figure 4 (A) Figure 4 (B) is a cross-sectional view of the power conversion device 1000. Figure 4 (A) is assembly Figure 1 The diagram shown is a cross-sectional view of the XX line after the power conversion device 1000. Figure 4 (B) is Figure 4 Enlarged cross-sectional view of the Y portion of (A). For... Figures 1-3 The same parts are given the same symbols and their descriptions are brief.

[0035] like Figure 4 As shown in (A), the housing 400 includes a cover 490 that houses a circuit board 900, a substrate 800, a molded busbar 500, a capacitor 200, etc. The housing 400 includes a first heat dissipation member 410 integrally formed with the housing 400.

[0036] like Figure 4As shown in (B), the molded busbar 500 is formed by stacking a first positive busbar 510, a second positive busbar 520, and a negative busbar 530 with electrical insulation layers. Furthermore, the first positive busbar 510 and the second positive busbar 520 are positioned opposite the first heat dissipation member 410 via an insulating member 550. As a result, the first positive busbar 510 and the second positive busbar 520 are in thermal contact with the first heat dissipation member 410 through the insulating member 550 and the first heat conduction member 600. The first heat conduction member 600 is, for example, a thermally conductive material such as grease or sheet material, and serves as a cooling path for the high-temperature member by transferring heat from the high-temperature member to the low-temperature member. Moreover, at least one of the first positive busbar 510 and the second positive busbar 520 may be configured to be in thermal contact with the first heat dissipation member 410 via the insulating member 550 and the first heat conduction member 600. More preferably, at least the first positive busbar 510, which generates a large amount of heat, is in thermal contact with the first heat dissipation member 410.

[0037] Furthermore, the insulating member 550 is formed of insulating resin or insulating paper, etc., and is a member that electrically insulates between different potentials. However, as shown in this example, a portion of a molded busbar 500 that seals the first positive busbar 510, the second positive busbar 520, and the negative busbar 530 may also be used. As another example, the surfaces of the first positive busbar 510 and the second positive busbar 520 opposite to the first heat dissipation member 410 may be exposed, and the insulating member 550 may be provided on the exposed surfaces.

[0038] According to this embodiment, by arranging the first positive bus 510 and the second positive bus 520, which have a greater heat generation than the negative bus 530, on the side opposite to the first heat dissipation member 410, the overall heat of the molded bus 500 can be reduced. Therefore, the amount of current flowing through the bus can be increased, thereby improving the output performance of the power conversion device 1000.

[0039] Furthermore, the housing 400 is divided into a first receiving space 401 and a second receiving space 402 by the first heat dissipation member 410. The semiconductor module 100 is housed in the first receiving space 401, and the capacitor 200 is housed in the second receiving space 402. This suppresses the conduction of heat from the semiconductor module 100 to the capacitor 200.

[0040] Figure 5 (A) Figure 5 (B) is a cross-sectional view showing a modified example of the power conversion device 1000, which is equivalent to Figure 4 Enlarged cross-sectional view of the Y portion of (A), Figure 5 (A) represents variation example 1. Figure 5 (B) represents variation example 2. Regarding... Figure 4 (B) The same parts are given the same symbols and their descriptions are brief.

[0041] exist Figure 5 In Modification 1 shown in (A), the thickness of the first positive bus 510 is made thicker than the thicknesses of the second positive bus 520 and the negative bus 530. By increasing the thickness of the first positive bus 510, the resistance of the first positive bus 510 is reduced, and the heat generated during energization is suppressed. Since the heat generation of the bus is suppressed, the current flowing through the bus can be increased accordingly, thereby improving the output performance of the power conversion device 1000. Furthermore, the thickness of the first positive bus 510 may also be thicker than at least one of the second positive bus 520 and the negative bus 530.

[0042] exist Figure 5 In Modification 2 shown in (B), the thickness of the insulating member 550 is thinner in the region where the first positive busbar 510 faces the first heat dissipation member 410 than in other regions. Since the insulating member 550 is thinner, the first heat-conducting member 600 is correspondingly thicker, but the thermal conductivity of the first heat-conducting member 600 is higher than that of the insulating member 550. Therefore, by thinning the thickness of the insulating member 550 in the region facing the first positive busbar 510, the heat dissipation efficiency of the first positive busbar 510 can be improved, and the temperature of the first positive busbar 510 can be reduced.

[0043] Figure 6 (A) Figure 6 (B) is a cross-sectional view showing a modified example of the power conversion device 1000, which is equivalent to Figure 4 Enlarged cross-sectional view of the Y portion of (A), Figure 6 (A) represents variation example 3. Figure 6 (B) represents variation example 4. Regarding... Figure 4 (B) The same parts are given the same symbols and their descriptions are brief.

[0044] exist Figure 6 In Modification 3 shown in (A), the distance between the first heat dissipation member 410 and the first positive electrode bus 510 is shorter in the region where the first positive electrode bus 510 and the first heat dissipation member 410 are opposite each other than in other regions. By further shortening the heat dissipation path from the first positive electrode bus 510 to the first heat dissipation member 410, the cooling efficiency of the first positive electrode bus 510 can be improved and the temperature of the first positive electrode bus 510 can be reduced.

[0045] exist Figure 6In variation 4 shown in (B), a second heat dissipation member 420 is provided on the opposite side of the first heat dissipation member 410, separated by the negative busbar 530, the first positive busbar 510, and the second positive busbar 520. The second heat dissipation member 420 is in thermal contact with the negative busbar 530 via a second heat conduction member 620. The second heat conduction member 620 is, for example, a thermally conductive material such as grease or sheet, and serves as a cooling path for the high-temperature member by transferring heat from the high-temperature member to the low-temperature member. The second heat dissipation member 420 can be the substrate 800 or other highly thermally conductive member that is in contact with the substrate 800 or the housing 400. The thickness of the first heat conduction member 600 is thinner than that of the second heat conduction member 620. By arranging heat dissipation members 410 and 420 on both sides of the molded busbar 500, the temperature of the busbar can be reduced. By making the thickness of the first heat conduction member 600 thinner than that of the second heat conduction member 620, the cooling efficiency of the first positive electrode bus 510, which generates a large amount of heat, can be increased, thereby reducing the temperature of the first positive electrode bus 510.

[0046] Figure 7 (A) Figure 7 (B) is a perspective view of a modified example 5 of the power conversion device 1000. Figure 7 (A) is an exploded stereograph. Figure 7 (B) is a perspective view before it is installed in the housing 400. (and) Figure 3 The difference in the example shown is that the molded busbar 500 and the capacitor 200 are constructed as a single unit. Regarding... Figure 1 , Figure 3 The same parts are given the same symbols and their descriptions are brief.

[0047] Figure 7 (A) is an exploded perspective view, showing the upper surface of capacitor 200 and molded busbar 500 as an integral structure. Although the diagram is omitted, the first positive busbar 510, the second positive busbar 520, and the negative busbar 530 of molded busbar 500 are connected to the positive and negative terminals of capacitor 200 by bolts or welding, thus forming an integral structure with molded busbar 500. Furthermore, the connection between molded busbar 500 and semiconductor module 100 is made via relay busbar 540.

[0048] like Figure 7As shown in (B), the molded bus 500 and capacitor 200 are an integral structure. The relay bus 540 is a two-layer stacked structure matching the first positive bus 510 and the second positive bus 520 and negative bus 530, in a mutually insulated state. One end of the first-layer relay bus 540 is fastened to the first positive bus 510 and the second positive bus 520 by bolts 560. One end of the second-layer relay bus 540 is fastened to the negative bus 530 by bolts 560. The other end of the first-layer relay bus 540 is connected to the positive side of the semiconductor module 100, and the other end of the second-layer relay bus 540 is connected to the negative side of the semiconductor module 100. The output terminals of the semiconductor module 100 are connected to the output bus 700.

[0049] Figure 8 (A) Figure 8 (B) is a perspective view of a modified example 6 of the power conversion device 1000. Figure 8 (A) is an exploded stereograph. Figure 8 (B) is a perspective view before it is installed in the housing 400. (and) Figure 7 (A) Figure 7 The example shown in (B) is the same, where the molded busbar 500 and capacitor 200 are integrated into one unit, but the difference is that the relay busbar 540 is not used. Figure 1 , Figure 3 , Figure 7 (A) Figure 7 (B) The same parts are given the same symbols and their descriptions are brief.

[0050] Figure 8 (A) is an exploded perspective view, showing the upper surface of capacitor 200 and molded busbar 500 as an integral structure. Although the diagram is omitted, the first positive busbar 510, the second positive busbar 520, and the negative busbar 530 of molded busbar 500 are connected to the positive and negative terminals of capacitor 200 by bolts or welding, thus forming an integral structure with molded busbar 500. Furthermore, the connection between molded busbar 500 and semiconductor module 100 is directly achieved through molded busbar 500.

[0051] like Figure 8 As shown in (B), the molded bus 500 and capacitor 200 are integrated into a single structure. The first positive bus 510 and the second positive bus 520 are connected to the positive side of the semiconductor module 100, and the negative bus 530 is connected to the negative side of the semiconductor module 100. The output terminals of the semiconductor module 100 are connected to the output bus 700. Since the relay bus 540 is not used, heat is not generated at the connection points with the relay bus 540. Furthermore, this simplifies the structure and reduces assembly time.

[0052] In modifications 5 and 6, at least one of the first positive busbar 510 and the second positive busbar 520 is also configured such that it is in thermal contact with the first heat dissipation member 410 via the insulating member 550 and the first heat conduction member 600. Therefore, even though the molded busbar 500 and the capacitor 200 are an integral structure, the heat generated by the first positive busbar 510 and the second positive busbar 520, which generate a lot of heat, can be reduced in a comprehensive manner. As a result, the current flowing through the busbars can be increased, thereby improving the output performance of the power conversion device 1000.

[0053] The following effects can be obtained by implementing the methods described above. (1) The power conversion device 1000 includes: a voltage conversion circuit 1100 that converts a first DC voltage to a second DC voltage; an inverter circuit 1200 that converts the second DC voltage to an AC voltage; a negative bus 530 that is connected to both the voltage conversion circuit 1100 and the inverter circuit 1200; a first positive bus 510 that is connected to the voltage conversion circuit 1100; a second positive bus 520 that is connected to the inverter circuit 1200; and a housing 400 that houses the voltage conversion circuit 1100. The device includes an inverter circuit 1200 and a first heat dissipation component 410 disposed within a housing 400. A first positive bus 510 and a second positive bus 520 are stacked on top of a negative bus 530 and electrically insulated from each other. The first positive bus 510 and the second positive bus 520 are positioned opposite the first heat dissipation component 410 via an insulating component 550. At least one of the first positive bus 510 and the second positive bus 520 is in thermal contact with the first heat dissipation component 410 via the insulating component 550 and a first heat conduction component 600. This reduces the heat generated by the buses and improves the output performance of the power conversion device.

[0054] This invention is not limited to the embodiments described above. Other embodiments that can be considered within the scope of the technical concept of this invention, as long as they do not impair the characteristics of this invention, are also included within the scope of this invention. Additionally, it may be a combination of the above embodiments and multiple variations. Symbol Explanation

[0055] 100, 100a, 100b, 100c, 100d semiconductor modules; 200, C1, C2, C3, C4 capacitors; 300 reactor; 400 housing; 401 first receiving space; 402 second receiving space; 403 inlet / outlet; 410 first heat dissipation component; 420 second heat dissipation component; 490 cover; 500 molded busbar; 510 first positive busbar; 520 second positive busbar; 530 negative busbar; 540 relay busbar; 550 insulating component; 600 first heat conduction component; 620 second heat conduction component; 700 output busbar; 710 current sensor; 800 substrate; 900 circuit board; 910 connector; 1000 power conversion device; 1100 voltage conversion circuit; 1200 inverter circuit; 1300 control circuit; T1~T8 semiconductor elements; D1~D8 diodes.

Claims

1. A power conversion device, characterized in that, have: A voltage conversion circuit that converts a first DC voltage into a second DC voltage; An inverter circuit that converts the second DC voltage into an AC voltage; The negative bus is connected to both the voltage conversion circuit and the inverter circuit. The first positive bus is connected to the voltage conversion circuit. The second positive bus is connected to the inverter circuit. A housing that accommodates the voltage conversion circuit and the inverter circuit; and A first heat dissipation component is disposed within the housing. The first positive busbar and the second positive busbar are stacked on top of the negative busbar and electrically insulated from each other. The first positive busbar and the second positive busbar are opposite to the first heat dissipation component through an insulating component. At least one of the first positive busbar and the second positive busbar is in thermal contact with the first heat dissipation component via the insulating component and the first heat conduction component. In the stacking direction of the first positive busbar, the second positive busbar, and the negative busbar, the first positive busbar and the second positive busbar are closer to the first heat dissipation component than the negative busbar.

2. The power conversion device according to claim 1, characterized in that, have: A semiconductor module, which incorporates semiconductor elements and constitutes the voltage conversion circuit and the inverter circuit; and a capacitor, which also constitutes the voltage conversion circuit and the inverter circuit. The first heat dissipation component divides the interior of the housing into a first accommodating space for accommodating the semiconductor module and a second accommodating space for accommodating the capacitor.

3. The power conversion device according to claim 2, characterized in that, The negative busbar, the first positive busbar, and the second positive busbar are opposite to the bottom surfaces of the first and second accommodating spaces and are disposed on the upper surfaces of the semiconductor module housed in the first accommodating space and the capacitor housed in the second accommodating space.

4. The power conversion device according to claim 3, characterized in that, The negative electrode bus is stacked on the opposite side of the semiconductor module and the capacitor, separated by the first positive electrode bus and the second positive electrode bus, and is on the first positive electrode bus and the second positive electrode bus.

5. The power conversion device according to claim 2, characterized in that, The first heat dissipation component is integrally formed with the housing.

6. The power conversion device according to claim 5, characterized in that, A cooling flow path is formed within the housing.

7. The power conversion device according to any one of claims 1 to 6, characterized in that, The thickness of the first positive busbar is greater than at least one of the second positive busbar and the negative busbar.

8. The power conversion device according to any one of claims 1 to 6, characterized in that, The thickness of the insulating component is thinner in the region opposite the first positive busbar and the first heat dissipation component than in other regions.

9. The power conversion device according to any one of claims 1 to 6, characterized in that, The distance between the first heat dissipation component and the first positive electrode bus is shorter in the area where the first positive electrode bus and the first heat dissipation component are opposite each other than in other areas.

10. The power conversion device according to claim 4, characterized in that, A second heat dissipation component is disposed on the side opposite to the first heat dissipation component, separated from the negative busbar, the first positive busbar, and the second positive busbar. The second heat dissipation component is in thermal contact with the negative busbar via the second heat conduction component.

11. The power conversion device according to claim 10, characterized in that, The thickness of the first heat-conducting component is thinner than that of the second heat-conducting component.

12. The power conversion device according to claim 2, characterized in that, have: A molded busbar, wherein the first positive busbar, the second positive busbar, and the negative busbar are sealed with insulating resin. The molded busbar is integrally formed with the capacitor.

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