Power conversion device

Abstract

The present application relates to a power conversion device including a power semiconductor module (4U, 4V, 4W) and a capacitor element (1b) for smoothing electric power, and a thermal resistance between the power semiconductor module (4U, 4V, 4W) and the capacitor element (1b) is set to be larger than a thermal resistance between the capacitor element (1b) and a capacitor module cooling flow path (1e, 1h).

Description

Technical Field

[0001] This disclosure relates to power conversion devices. Background Technology

[0002] Hybrid electric vehicles, electric vehicles, and other electric drive vehicles (hereinafter referred to as vehicles) are equipped with an AC rotary motor for vehicle drive and a power conversion device that converts power between the AC rotary motor and the vehicle battery. However, the space available for mounting the power conversion device is usually limited, thus requiring miniaturization of the power conversion device mounted in the vehicle. Therefore, in order to miniaturize the power conversion device mounted in the aforementioned vehicles, the prior art has been focused on miniaturizing components such as power semiconductor modules and smoothing capacitors that constitute the main circuit of the power conversion device.

[0003] When mounting a power conversion device in a vehicle, the most important thing is to reduce the projected area of ​​the power conversion device as a floor space. Therefore, the smoothing capacitor is usually configured with other components such that the projected area of ​​the smoothing capacitor, which is a large component of the power conversion device, overlaps with the projected area of ​​the other components of the power conversion device.

[0004] For example, the conventional power conversion device disclosed in Patent Document 1 comprises: a capacitor module having a capacitor cooling flow path embedded in a capacitor housing; and a power semiconductor module integrally provided with a power semiconductor cooler having a power semiconductor cooling flow path internally disposed therein. The capacitor housing and the power semiconductor cooler are joined in a surface contact state, and the capacitor cooling flow path and the power semiconductor cooling flow path are directly connected to each other to allow the cooling medium to circulate. In the conventional power conversion device disclosed in Patent Document 1, the capacitor module and the power semiconductor module are arranged in an overlapping configuration, such that the projected area of ​​the power semiconductor module overlaps with the projected area of ​​the capacitor module.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent No. 7052447 Summary of the Invention

[0008] The technical problem that the invention aims to solve

[0009] The existing power conversion device disclosed in Patent Document 1 is constructed based on the premise that "the cooling capacity of the power semiconductor cooler is lower than that of the capacitor module". By making the power semiconductor cooler and the upper surface of the capacitor module in a surface contact state, the heat generated by the power semiconductor module is dissipated not only through the power semiconductor module cooler, but also on the capacitor module side, thereby efficiently cooling the power semiconductor module.

[0010] However, in the existing power conversion device disclosed in Patent Document 1, the heat generated by the power semiconductor module is transferred to the capacitor module, which is in surface contact with the power semiconductor module, and further to the capacitor elements disposed inside the capacitor module. Therefore, in the case of this existing power conversion device, the cooling flow path of the capacitor module used to cool the capacitor elements needs to be enlarged, which leads to the problem of increasing the size of the power conversion device.

[0011] Furthermore, in reality, there is almost no situation where the cooling capacity of a power semiconductor module cooler is lower than that of a cooler for a capacitor module. On the contrary, the cooling capacity of a power semiconductor module cooler is higher than that of a cooler for a capacitor module.

[0012] This disclosure aims to provide a technology for solving the above-mentioned problems, with the objective of providing a power conversion device that achieves miniaturization.

[0013] Technical solutions to solve technical problems

[0014] The power conversion device disclosed herein has a power conversion circuit composed of multiple power semiconductor elements, and performs power conversion between DC power and AC power through the switching operation of the power semiconductor elements. The power conversion device is characterized by comprising: A power semiconductor module, the power semiconductor module having the power semiconductor element; A power semiconductor module cooler for cooling the power semiconductor module; and A capacitor module, connected to the DC terminal of the power conversion circuit, includes capacitor elements that smooth the voltage and current at the DC terminal. The capacitor module has: A capacitor housing that houses the capacitor element; A wiring board housed in the capacitor housing; A capacitor module cooling path, housed within the capacitor housing, cools the capacitor elements; and The sleeve, in combination with the power semiconductor module cooler, forms a power semiconductor module cooling flow path for cooling the power semiconductor module. The cooling path of the power semiconductor module is interconnected with the cooling path of the capacitor module. The thermal resistance between the power semiconductor module and the capacitor element is configured to be greater than the thermal resistance between the capacitor element and the cooling flow path of the capacitor module.

[0015] Invention Effects

[0016] According to the power conversion device disclosed herein, a miniaturized power conversion device can be obtained. Attached Figure Description

[0017] Figure 1 This is a perspective view schematically showing the overall structure of the power conversion device involved in embodiments 1, 4, 5, and 6.

[0018] Figure 2 It is along Figure 1 A cross-sectional view of the power conversion device according to Embodiment 1, viewed from the direction of arrow S at the section of line AA.

[0019] Figure 3 It is along Figure 1 A cross-sectional view of the power conversion device according to Embodiment 1, viewed from the direction of arrow S at the cross section of line BB.

[0020] Figure 4 This is a perspective view schematically showing the overall structure of the power conversion device involved in embodiments 2 and 3.

[0021] Figure 5 It is along Figure 4 A cross-sectional view of the power conversion device involved in Embodiment 2, viewed from the direction of arrow S at the cross section of line CC.

[0022] Figure 6 It is along Figure 4 A cross-sectional view of the power conversion device involved in Embodiment 3, viewed from the direction of arrow S at the cross section of line CC.

[0023] Figure 7 It is along Figure 1 A cross-sectional view of the power conversion device involved in Embodiment 4, viewed from the direction of arrow S at the section of line AA.

[0024] Figure 8 It is along Figure 1 A cross-sectional view of the power conversion device involved in Embodiment 5, viewed from the direction of arrow S at the section of line AA.

[0025] Figure 9 It is along Figure 1 A cross-sectional view of the power conversion device involved in Embodiment 6, viewed from the direction of arrow S at the section of line AA. Detailed Implementation

[0026] As is well known, a three-phase power conversion device includes a power conversion circuit composed of a three-phase bridge circuit, which includes: a U-phase arm, which is composed of a series connection of a U-phase upper arm power semiconductor element and a U-phase lower arm power semiconductor element; a V-phase arm, which is composed of a series connection of a V-phase upper arm power semiconductor element and a V-phase lower arm power semiconductor element; and a W-phase arm, which is composed of a series connection of a W-phase upper arm power semiconductor element and a W-phase lower arm power semiconductor element.

[0027] U-phase AC terminals are derived from the series connection between the upper U-phase power semiconductor element and the lower U-phase power semiconductor element; V-phase AC terminals are derived from the series connection between the upper V-phase power semiconductor element and the lower V-phase power semiconductor element; and W-phase AC terminals are derived from the series connection between the upper W-phase power semiconductor element and the lower W-phase power semiconductor element.

[0028] In addition, the U-phase arm, V-phase arm and W-phase arm are connected in parallel to each other, and a positive DC terminal is led out from the upper arm of each phase connected in parallel, and a negative DC terminal is led out from the lower arm of each phase connected in parallel. A smoothing capacitor is connected between the positive DC terminal and the negative DC terminal.

[0029] The aforementioned U-phase AC terminal, V-phase AC terminal, and W-phase AC terminal are connected, for example, to the armature winding of a three-phase AC rotating motor, the positive DC terminal is connected, for example, to the positive terminal of a battery mounted on a vehicle, and the negative DC terminal is connected to the negative terminal of the battery.

[0030] Implementation method 1.

[0031] Figure 1 This is a perspective view schematically illustrating the overall structure of the power conversion devices according to Embodiments 1, 4, 5, and 6. Examples of the aforementioned three-phase power conversion devices are shown, including the power conversion device 100 according to Embodiment 1, the power conversion device 400 according to Embodiment 4, the power conversion device 500 according to Embodiment 5, and the power conversion device 600 according to Embodiment 6. In the following... Figure 1 In the description, the power conversion device 100 according to Embodiment 1 will be described.

[0032] exist Figure 1 In the power conversion device 100, there are: a capacitor module 1; and a U-phase power semiconductor module 4U, a V-phase power semiconductor module 4V, and a W-phase power semiconductor module 4W mounted on the upper surface portion 11 of the capacitor module 1 via a power semiconductor module cooler (not shown). In the following description, the U-phase power semiconductor module 4U, the V-phase power semiconductor module 4V, and the W-phase power semiconductor module 4W are sometimes collectively referred to as the respective phase power semiconductor modules 4U, 4V, and 4W.

[0033] In capacitor module 1, a smoothing capacitor (not shown) is embedded in a synthetic resin such as epoxy resin or silicone resin, and an internal cooling flow path is provided for the refrigerant, such as water, used to cool the smoothing capacitor. The capacitor module cooling flow path is connected to a refrigerant inlet 101 and a refrigerant outlet 102, which are open at the bottom surface 12 of capacitor module 1. The refrigerant inlet 101 and the refrigerant outlet 102 constitute a refrigerant input / output unit.

[0034] A refrigerant inlet 101 is located on the side near the first side portion 13 and the second side portion 14 of the capacitor module 1, opening on the bottom portion 12 and connected to an external cooling flow path (not shown) located outside the capacitor module 1, through which refrigerant is introduced. A refrigerant outlet 102 is located on the side near the third side portion 15 and the second side portion 14 of the capacitor module 1, opening on the bottom portion 12 and connected to the external cooling flow path, through which refrigerant flowing in the power semiconductor module cooling flow path and the capacitor module cooling flow path (described later) is discharged. Additionally, a fourth side portion 16 is a sidewall portion opposite to the second side portion 14.

[0035] The U-phase power semiconductor module 4U is configured such that the upper U-phase power semiconductor element and the lower U-phase power semiconductor element constituting the U-phase arm are sealed, for example, with a semiconductor sealing epoxy resin whose main components are epoxy thermosetting resin and filler.

[0036] The V-phase power semiconductor module 4V is configured such that the upper V-phase power semiconductor element and the lower V-phase power semiconductor element constituting the V-phase arm are sealed, for example, with a semiconductor sealing epoxy resin whose main components are epoxy thermosetting resin and filler.

[0037] The W-phase power semiconductor module 4W is configured such that the upper W-phase power semiconductor element and the lower W-phase power semiconductor element constituting the W-phase arm are sealed, for example, with a semiconductor sealing epoxy resin whose main components are epoxy thermosetting resin and filler.

[0038] Figure 2 It is along Figure 1 A cross-sectional view of the power conversion device according to Embodiment 1, viewed from the direction of arrow S at the cross-section of line AA. Figure 3 It is along Figure 1 A cross-sectional view of the power conversion device according to Embodiment 1, viewed from the direction of arrow S at the cross-section of line BB. Figure 1 , Figure 2 and Figure 3 In the power conversion device 100, it is generally composed of a capacitor module 1, a U-phase power semiconductor module 4U, a V-phase power semiconductor module 4V, a W-phase power semiconductor module 4W, and a bus assembly 5.

[0039] The capacitor module 1 comprises: a capacitor housing 1a; a capacitor element 1b housed in the capacitor housing 1a; a flat wiring board 1c housed in the capacitor housing 1a and disposed opposite to the upper surface of the capacitor element 1b at a distance; a connecting busbar 1d whose end is housed in the capacitor housing 1a and whose end is connected to wiring (not shown) provided on the wiring board 1c by means of welding or brazing; a synthetic resin 1f filling the internal space of the capacitor housing 1a and embedding a portion of the capacitor element 1b, the wiring board 1c, and the connecting busbar 1d; and a water jacket 1g placed on the upper surface of the synthetic resin 1f filled in the capacitor housing 1a and serving as a sleeve formed of synthetic resin. The wiring board 1c is, for example, made of a printed circuit board on an insulating substrate by printing wiring.

[0040] The capacitor housing 1a is configured as a generally rectangular parallelepiped with an open top, and is made of metal or synthetic resin. The capacitor element 1b constitutes a smoothing capacitor that smooths the DC current and DC voltage at the DC terminals in the power conversion circuit. The capacitor element 1b is housed inside the capacitor housing 1a. Furthermore, there may be one or more capacitor elements 1b.

[0041] The synthetic resin 1f filling the internal space of the capacitor housing 1a is, for example, epoxy resin. Alternatively, silicone resin (silicone rubber) may be used instead of epoxy resin as the synthetic resin 1f.

[0042] The capacitor module cooling flow path 1e, which is connected to the refrigerant inlet port 101, and the capacitor module cooling flow path 1h, which is connected to the refrigerant outlet port 102, are embedded in the synthetic resin 1f filled in the capacitor housing 1a, and are close to the refrigerant outlet port 102. Figure 1 The second side portion 14 shown is positioned opposite the side portion of the capacitor element 1b. The capacitor element 1b is cooled by refrigerant flowing in the capacitor module cooling flow paths 1e and 1h.

[0043] The synthetic resin material constituting the water jacket 1g is, for example, epoxy resin or silicone resin (silicone rubber). The water jacket 1g is disposed between the power semiconductor modules 4U, 4V, and 4W disposed on the upper surface 11 side of the capacitor module 1 and the capacitor housing 1a. The water jacket 1g includes a power semiconductor module cooling flow path 2 open on the upper surface side.

[0044] In capacitor module 1, the positional relationship of each structural element is arranged from the upper surface 11 side to the bottom surface 12 side in the order of water jacket 1g made of synthetic resin, wiring board 1c, and capacitor element 1b.

[0045] The power semiconductor module cooling flow path 2 in the water jacket 1g is shaped to correspond to the dimensions of the entire bottom surface of each phase power semiconductor module 4U, 4V, and 4W, and is connected to the aforementioned capacitor module cooling flow paths 1e and 1h. A power semiconductor module cooler 3 is fitted into the upper surface of the water jacket 1g, thereby sealing the open upper surface side of the power semiconductor module cooling flow path 2. Thus, the power semiconductor module cooling flow path 2 is formed by combining the power semiconductor module cooler 3 with the water jacket 1g.

[0046] The power semiconductor module cooler 3 is made of metal such as die-cast aluminum or sheet metal, and is in surface contact with the bottom surfaces of each phase power semiconductor module 4U, 4V, and 4W. Therefore, each phase power semiconductor module 4U, 4V, and 4W is cooled by the cooling medium flowing in the power semiconductor module cooling flow path 2 via the power semiconductor module cooler 3.

[0047] Each phase power semiconductor module 4U, 4V, and 4W includes a positive DC terminal 41 and an AC terminal 42. The positive DC terminal 41 of each phase power semiconductor module 4U, 4V, and 4W is connected to the connecting bus 1d by soldering or brazing, and is connected to the terminal (not shown) of the capacitor element 1b via the wiring board 1c.

[0048] The negative DC terminals (not shown) of the power semiconductor modules 4U, 4V, and 4W of each phase are connected to the negative terminals (not shown) of capacitor element 1b.

[0049] The connecting bus 1d can be composed of three connecting buses corresponding to the positive DC terminals 41 of each phase power semiconductor module 4U, 4V, and 4W, or it can be composed of a single wide connecting bus.

[0050] The bus assembly 5 integrates three output buses 5a corresponding to phases U, V, and W, respectively, with current sensors 5b for phases U, V, and W installed on these output buses 5a. The three output buses 5a corresponding to phases U, V, and W are connected to the respective AC terminals 42 of the power semiconductor modules 4U, 4V, and 4W by welding or brazing.

[0051] The bottom surfaces of the current sensors 5b for each of the U-phase, V-phase, and W-phase in the busbar assembly 5 are joined to the upper surface of the power semiconductor module cooler 3 in a surface contact state. Furthermore, the power semiconductor module cooler 3, the power semiconductor module 4, and the current sensors 5b are thermally bonded, for example, using thermal bonding components (not shown) such as thermal grease or heat sinks.

[0052] The capacitor module cooling flow paths 1e and 1h are directly connected to the power semiconductor module cooling flow path 2. Refrigerant flowing from the outside of the power conversion device 100 into the refrigerant inlet 101 flows in the order of capacitor module cooling flow path 1e, power semiconductor module cooling flow path 2, and capacitor module cooling flow path 1h, and flows out from the refrigerant outlet 102 to the outside of the power conversion device 100. With the refrigerant flowing as described above, the capacitor module 1, the power semiconductor modules 4U, 4V, and 4W of each phase, and the current sensor 5b of each phase are efficiently cooled.

[0053] The power conversion device 100 according to Embodiment 1 is configured such that the combined equivalent thermal resistance Rtha [K / W] of the water jacket 1g, synthetic resin 1f and wiring board 1c made of synthetic resin located between the power semiconductor modules 4U, 4V, 4W and the capacitor element 1b is greater than the thermal resistance Rthb [K / W] of the synthetic resin 1f located between the capacitor element 1b and the cooling flow paths 1e, 1h of the capacitor module.

[0054] As a specific means to make the above-mentioned equivalent thermal resistance Rtha [K / W] greater than the thermal resistance Rthb [K / W] of the synthetic resin 1f, there is a so-called material factor-based method. This method selects the materials of each synthetic resin and wiring board so that the thermal resistance of the synthetic resin constituting the water jacket 1g, the thermal resistance of the wiring board 1c, and the thermal resistance of the synthetic resin 1f located between the capacitor element 1b and the water jacket 1g is smaller than the thermal resistance of the synthetic resin 1f located between the capacitor element 1b and the cooling flow paths 1e and 1h of the capacitor module.

[0055] In addition to the material-based method mentioned above, a so-called structural-based method can also be used, in which the thickness of the synthetic resin constituting the water jacket 1g, the thickness of the synthetic resin 1f located between the capacitor element 1b and the water jacket 1g, and the thickness of the wiring board 1c are combined to obtain a thickness greater than the thickness of the synthetic resin 1f located between the capacitor element 1b and the capacitor module cooling flow paths 1e and 1h.

[0056] According to the power conversion device of Embodiment 1 as described above, since the combined equivalent thermal resistance Rtha of the structural elements, namely the water jacket 1g, the synthetic resin 1f, and the wiring board 1c, which are located between the power semiconductor modules 4U, 4V, and 4W of each phase and the capacitor element 1b, is greater than the thermal resistance Rthb of the synthetic resin 1f located between the capacitor element 1b and the capacitor module cooling flow path 1e, all the heat generated by the power semiconductor modules 4U, 4V, and 4W is dissipated by the power semiconductor module cooler 3, and the heat flowing into the capacitor module 1 via the water jacket 1g made of synthetic resin is eliminated, thereby effectively achieving the cooling of the capacitor element 1b by the capacitor module cooling flow paths 1e and 1h.

[0057] As a result, capacitor element 1b can be prevented from getting hot due to the heat generated by each phase power semiconductor module 4U, 4V, 4W, thereby enabling miniaturization of capacitor module 1.

[0058] Furthermore, in the power conversion device according to Embodiment 1, each phase current sensor 5b and each phase power semiconductor module 4U, 4V, 4W are thermally connected to the power semiconductor module cooler 3. However, if the output power is small and the heat generation in each phase current sensor 5b is small, the same effect as described above can be obtained even if each phase current sensor 5b is not thermally connected to the power semiconductor module cooler 3.

[0059] Furthermore, in the power conversion device according to Embodiment 1, the water jacket 1g made of synthetic resin and the synthetic resin 1f of the capacitor module 1 are different components, but they can also be configured as an integral structure of synthetic resin, in which case the same effect as described above can be obtained.

[0060] Furthermore, in the power conversion device according to Embodiment 1, the connecting bus 1d and the output bus 5a are metal busbars, but conductive components such as cables and wiring boards can also be used instead of metal busbars, and the same effect as described above can be obtained in this case.

[0061] Implementation method 2.

[0062] Next, the power conversion device according to Embodiment 2 will be described. Figure 4 This is a perspective view schematically showing the overall structure of the power conversion device involved in embodiments 2 and 3, illustrating an example of the aforementioned three-phase power conversion device. Figure 4 In the capacitor module 1, the refrigerant inlet hole 101, which serves as a refrigerant input and output unit, is located on the side near the first side portion 13 and the fourth side portion 16 of the capacitor module 1. It opens on the bottom portion 12 and is connected to an external cooling flow path (not shown) provided outside the capacitor module 1, through which refrigerant is input.

[0063] The refrigerant output port 102, which serves as a refrigerant input / output unit, opens on the bottom part 12 on the side near the first side part 13 and the second side part 14 of the capacitor module 1, and is connected to the external cooling flow path, outputting refrigerant flowing in the power semiconductor module cooling flow path and the capacitor module cooling flow path to the external cooling flow path. Figure 4 Other structures in Figure 1 The structures shown are the same.

[0064] In capacitor module 1, the capacitor module cooling flow path 1i, which is connected to the refrigerant inlet 101, is embedded in the synthetic resin 1f filled in the capacitor housing 1a, and is close to the refrigerant inlet 101. Figure 4 The bottom portion 12 shown is positioned opposite the bottom portion of the capacitor element 1b. The cooling flow path 1i of the capacitor module has a planar shape that corresponds to the entire bottom portion of the capacitor element 1b, but it may also have a shape that corresponds to a portion of the bottom portion of the capacitor element 1b.

[0065] The capacitor module cooling flow path 1i is set near and Figure 4 The connection flow path (not shown) at the position of the side portion of the capacitor element 1b opposite to the second side portion 14 or the side portion of the capacitor element 1b opposite to the fourth side portion 16 is connected to the power semiconductor module cooling flow path 2.

[0066] Additionally, the capacitor module cooling flow path 1j, which is connected to the refrigerant outlet 102, is embedded in the synthetic resin 1f filled in the capacitor housing 1a, and is close to the refrigerant outlet 102. Figure 4 The second side portion 14 shown is disposed opposite to the side portion of the capacitor element 1b and connected to the power semiconductor module cooling flow path 2 of the water jacket 1g. The capacitor element 1b is cooled by refrigerant flowing in the capacitor module cooling flow paths 1i, 1j and the aforementioned connecting flow path.

[0067] The refrigerant flowing into the refrigerant inlet 101 from outside the power conversion device 200 circulates in the following order: capacitor module cooling flow path 1i, connection flow path (not shown), power semiconductor module cooling flow path 2, and capacitor module cooling flow path 1j, and then flows out of the power conversion device 200 from the refrigerant outlet 102. The refrigerant circulates as described above, thereby efficiently cooling the capacitor module 1, the power semiconductor modules 4U, 4V, and 4W of each phase, and the current sensor 5b of each phase.

[0068] The power conversion device 200 according to Embodiment 2 is configured such that the combined equivalent thermal resistance Rtha [K / W] of the water jacket 1g, synthetic resin 1f and wiring board 1c made of synthetic resin located between the power semiconductor modules 4U, 4V, 4W and the capacitor element 1b is greater than the thermal resistance Rthb [K / W] of the synthetic resin 1f located between the capacitor element 1b and the cooling flow paths 1i, 1j of the capacitor module.

[0069] As a specific means to make the above-mentioned equivalent thermal resistance Rtha [K / W] greater than the thermal resistance Rthb [K / W] of the synthetic resin 1f, there is a so-called material factor-based method. This method selects the materials of each synthetic resin and the wiring board so that the thermal resistance of the synthetic resin constituting the water jacket 1g, the thermal resistance of the wiring board 1c, and the thermal resistance of the synthetic resin 1f located between the capacitor element 1b and the water jacket 1g is smaller than that of the synthetic resin 1f located between the capacitor element 1b and the cooling flow paths 1i and 1j of the capacitor module.

[0070] In addition to the material-based method mentioned above, a so-called structural-based method can also be used, in which the thickness of the synthetic resin constituting the water jacket 1g, the thickness of the synthetic resin 1f located between the capacitor element 1b and the water jacket 1g, and the thickness of the wiring board 1c are combined to obtain a thickness that is greater than the thickness of the synthetic resin 1f located between the capacitor element 1b and the capacitor module cooling flow paths 1i and 1j.

[0071] The other structures are the same as those in Implementation Method 1.

[0072] According to the power conversion device of Embodiment 2 as described above, since the combined equivalent thermal resistance Rtha of the structural elements located between the power semiconductor modules 4U, 4V, 4W and the capacitor element 1b—namely, the water jacket 1g made of synthetic resin, the synthetic resin 1f, and the wiring board 1c—is greater than the thermal resistance Rthb of the synthetic resin 1f located between the capacitor element 1b and the capacitor module cooling flow path 1e, all the heat generated by the power semiconductor modules 4U, 4V, 4W is dissipated by the power semiconductor module cooler 3, and the heat flowing into the capacitor module 1 via the water jacket 1g made of synthetic resin is eliminated. This enables the cooling of the capacitor element 1b by the capacitor module cooling flow paths 1i, 1j, and the connecting flow path. As a result, the capacitor element 1b can be prevented from being heated by the heat generated by the power semiconductor modules 4U, 4V, 4W, thereby enabling the miniaturization of the capacitor module 1.

[0073] Furthermore, according to the power conversion device of Embodiment 2, since the refrigerant inlet 101, the refrigerant outlet 102, and the capacitor module cooling flow path 1i are arranged on the bottom side of the capacitor element 1b, the capacitor element 1b and the capacitor module cooling flow paths 1i and 1j do not interfere with each other in position, thereby enabling the refrigerant inlet 101 and the refrigerant outlet 102 to be arranged at any position on the bottom side of the capacitor element 1b.

[0074] Furthermore, in the power conversion device according to Embodiment 2, each phase current sensor 5b and each phase power semiconductor module 4U, 4V, 4W are thermally connected to the power semiconductor module cooler 3. However, if the output power is small and the heat generation in each phase current sensor 5b is small, the same effect as described above can be obtained even if each phase current sensor 5b is not thermally connected to the power semiconductor module cooler 3.

[0075] Furthermore, in the power conversion device according to Embodiment 2, the water jacket 1g made of synthetic resin and the synthetic resin 1f of the capacitor module 1 are different components, but they can also be configured as an integral structure using synthetic resin, in which case the same effect as described above can be obtained.

[0076] Furthermore, in the power conversion device according to Embodiment 2, the connecting bus 1d and the output bus 5a are metal busbars, but conductive components such as cables and wiring boards can also be used instead of metal busbars, and the same effect as described above can be obtained in this case.

[0077] Implementation method 3.

[0078] Next, the power conversion device according to Embodiment 3 will be described. Figure 6 It is along Figure 4 A cross-sectional view of the power conversion device involved in Embodiment 3, viewed from the direction of arrow S at the cross-section of line CC. Figure 4 and Figure 6 In this capacitor module 1, a capacitor housing 1a, a capacitor element 1b, a flat wiring board 1c, a connecting busbar 1d, a synthetic resin 1f, and a water jacket 1gi are constructed. The capacitor element 1b is housed in the capacitor housing 1a, and the flat wiring board 1c is housed in the capacitor housing 1a, facing the upper surface of the capacitor element 1b with a gap between them. The end of the connecting busbar 1d is housed in the capacitor housing 1a and is connected to the wiring board 1c by welding or brazing. The synthetic resin 1f fills the internal space of the capacitor housing 1a and embeds a portion of the capacitor element 1b, the wiring board 1c, and the connecting busbar 1d. The water jacket 1gi is placed on the upper surface of the capacitor housing 1a and serves as a sleeve made of metal.

[0079] The refrigerant flowing into the refrigerant inlet 101 from outside the power conversion device 300 circulates in the following order: capacitor module cooling flow path 1i, connection flow path (not shown), power semiconductor module cooling flow path 2 provided in the water jacket 1gi made of metal, and capacitor module cooling flow path 1j, and then flows out from the refrigerant outlet 102 to the outside of the power conversion device 200. The refrigerant circulates as described above, thereby efficiently cooling the capacitor module 1, the power semiconductor modules 4U, 4V, and 4W of each phase, and the current sensor 5b of each phase.

[0080] The power conversion device 300 according to Embodiment 3 is configured such that the combined equivalent thermal resistance Rtha [K / W] of the water jacket 1gi, synthetic resin 1f and wiring board 1c made of synthetic resin located between the power semiconductor modules 4U, 4V, 4W and the capacitor element 1b is greater than the thermal resistance Rthb [K / W] of the synthetic resin 1f located between the capacitor element 1b and the cooling flow paths 1i, 1j of the capacitor module.

[0081] As a specific means to make the above-mentioned equivalent thermal resistance Rtha [K / W] greater than the thermal resistance Rthb [K / W] of the synthetic resin 1f, there is a so-called material factor-based method. This method selects the materials of each synthetic resin and the wiring board so that the thermal resistance relative to the metal constituting the water jacket 1gi, the thermal resistance of the wiring board 1c, and the thermal resistance of the synthetic resin 1f located between the capacitor element 1b and the water jacket 1gi, and the thermal resistance of the synthetic resin 1f located between the capacitor element 1b and the cooling flow paths 1i and 1j of the capacitor module are reduced.

[0082] In addition to the above-mentioned material-based method, a so-called structural-based method can also be used, that is, the thickness of the synthetic resin 1f located between the capacitor element 1b and the water jacket 1gi and the thickness of the wiring board 1c is greater than the thickness of the synthetic resin 1f located between the capacitor element 1b and the cooling flow paths 1i and 1j of the capacitor module.

[0083] The other structures are the same as those in Implementation Method 1.

[0084] According to the power conversion device of Embodiment 3 as described above, since the combined equivalent thermal resistance Rtha of the structural elements—namely, the metal water jacket 1gi, the synthetic resin 1f, and the wiring board 1c—located between the power semiconductor modules 4U, 4V, and 4W and the capacitor element 1b is greater than the thermal resistance Rthb of the synthetic resin 1f located between the capacitor element 1b and the capacitor module cooling flow path 1e, all the heat generated by the power semiconductor modules 4U, 4V, and 4W is dissipated by the power semiconductor module cooler 3, and the heat flowing into the capacitor module 1 via the metal water jacket 1gi is eliminated. This enables the cooling of the capacitor element 1b by the capacitor module cooling flow paths 1i, 1j, and the connecting flow path. As a result, the capacitor element 1b can be prevented from being heated by the heat generated by the power semiconductor modules 4U, 4V, and 4W, thereby enabling the miniaturization of the capacitor module 1.

[0085] According to the power conversion device of Embodiment 3, most of the heat generated by the power semiconductor modules 4U, 4V, and 4W is dissipated by the power semiconductor module cooler 3, which is fitted with a water jacket 1gi made of metal. However, a portion of the heat is conducted to the wiring board 1c via the water jacket 1gi and the synthetic resin 1f. However, when the wiring board 1c is, for example, made of a printed wiring board, the wiring board 1c has high thermal conductivity in the planar direction but low thermal conductivity in the thickness direction. As a result, the heat conducted to the wiring board 1c is not conducted to the capacitor element 1b.

[0086] Therefore, capacitor element 1b is sufficiently cooled by the capacitor module cooling flow paths 1i and 1j. As a result, capacitor element 1b can be prevented from overheating due to the heat generated by the power semiconductor modules 4U, 4V, and 4W, thereby enabling miniaturization of capacitor module 1.

[0087] Therefore, the power conversion device according to Embodiment 3 is configured as follows, similar to the power conversion device of Embodiment 2, such that the combined equivalent thermal resistance Rtha [K / W] of the metal water jacket 1gi, synthetic resin 1f and wiring board 1c located between the power semiconductor modules 4U, 4V, 4W and the capacitor element 1b is greater than the thermal resistance Rthb [K / W] of the synthetic resin 1f located between the capacitor element 1b and the cooling flow paths 1i, 1j of the capacitor module.

[0088] The other structures of the power conversion device involved in Embodiment 3 are the same as those of the power conversion device involved in Embodiment 2.

[0089] According to the power conversion device of Embodiment 3 as described above, the heat generated by each phase power semiconductor module 4U, 4V, and 4W is dissipated by the power semiconductor module cooler 3 and the water jacket 1gi made of metal, and the heat flowing into the capacitor module 1 is eliminated, thereby attempting to achieve cooling of the capacitor element 1b by the capacitor module cooling flow paths 1i and 1j and the connecting flow path. As a result, the capacitor element 1b can be prevented from being heated by the heat generated by each phase power semiconductor module 4U, 4V, and 4W, thereby enabling the miniaturization of the capacitor module 1.

[0090] Furthermore, according to the power conversion device of Embodiment 3, since the refrigerant inlet 101, the refrigerant outlet 102, and the capacitor module cooling flow path 1i are arranged on the lower surface side of the capacitor element 1b, the capacitor element 1b and the capacitor module cooling flow paths 1i and 1j do not interfere with each other in position, thereby enabling the refrigerant inlet 101 and the refrigerant outlet 102 to be arranged at any position on the bottom surface side of the capacitor element 1b.

[0091] Furthermore, in the power conversion device according to Embodiment 3, each phase current sensor 5b and each phase power semiconductor module 4U, 4V, 4W are thermally connected to the power semiconductor module cooler 3. However, if the output power is small and the heat generation in each phase current sensor 5b is small, the same effect as described above can be obtained even if each phase current sensor 5b is not thermally connected to the power semiconductor module cooler 3.

[0092] Furthermore, in the power conversion device according to Embodiment 3, the connecting bus 1d and the output bus 5a are metal busbars, but conductive components such as cables and wiring boards can also be used instead of metal busbars, and the same effect as described above can be obtained in this case.

[0093] Implementation method 4.

[0094] Next, the power conversion device according to Embodiment 4 will be described. Figure 7 It is along Figure 1 A cross-sectional view of the power conversion device according to Embodiment 4, viewed from the direction of arrow S at the section of line AA. Figure 1 , Figure 7 In the capacitor module 1, there are: a capacitor housing 1a; a capacitor element 1b housed in the capacitor housing 1a; a flat wiring board 1c housed in the capacitor housing 1a and positioned opposite the upper surface of the capacitor element 1b across a gap; and a discharge unit 1k, such as a discharge resistor, disposed on the upper surface of the wiring board 1c. The discharge unit 1k is a unit that discharges residual charge from the capacitor element 1b as needed.

[0095] In addition, the capacitor module 1 includes: a connecting bus 1d, the end of which is housed in the capacitor housing 1a and connected to the wiring board 1c by welding or brazing; a synthetic resin 1f, which fills the internal space of the capacitor housing 1a and embeds the capacitor element 1b, the wiring board 1c, the discharge unit 1k and a portion of the connecting bus 1d; and a water jacket 1g, which is placed on the upper surface of the capacitor housing 1a and serves as a sleeve formed of synthetic resin.

[0096] The power conversion device 400 of Embodiment 4 is similar to the power conversion device of Embodiment 1 described above, wherein the combined equivalent thermal resistance Rtha [K / W] of the water jacket 1g, synthetic resin 1f, discharge unit 1k and wiring board 1c made of synthetic resin located between the power semiconductor modules 4U, 4V, 4W and the capacitor element 1b is greater than the thermal resistance Rthb [K / W] of the synthetic resin 1f located between the capacitor element 1b and the cooling flow paths 1e, 1h of the capacitor module.

[0097] As a specific means to make the above-mentioned equivalent thermal resistance Rtha [K / W] greater than the thermal resistance Rthb [K / W] of the synthetic resin 1f, there is a so-called material factor-based method. This method selects the materials of each synthetic resin and the wiring board so that the thermal resistance of the synthetic resin constituting the water jacket 1g, the thermal resistance of the synthetic resin 1f located between the capacitor element 1b and the water jacket 1g, and the thermal resistance of the wiring board 1c are smaller than the thermal resistance of the synthetic resin 1f located between the capacitor element 1b and the cooling flow paths 1e and 1h of the capacitor module.

[0098] In addition to the material-based method mentioned above, a so-called structural-based method can also be used, in which the thickness of the synthetic resin constituting the water jacket 1g, the thickness of the synthetic resin 1f located between the capacitor element 1b and the water jacket 1g, and the thickness of the wiring board 1c are combined to obtain a thickness greater than the thickness of the synthetic resin 1f located between the capacitor element 1b and the capacitor module cooling flow paths 1e and 1h.

[0099] The other structures of the power conversion device involved in Embodiment 4 are the same as those of the power conversion device involved in Embodiment 1.

[0100] According to the power conversion device of Embodiment 4 as described above, since the combined equivalent thermal resistance Rtha of the structural elements located between each phase power semiconductor module 4U, 4V, 4W and the capacitor element 1b—namely, the water jacket 1g made of synthetic resin, the synthetic resin 1f, the discharge unit 1k, and the wiring board 1c—is greater than the thermal resistance Rthb of the synthetic resin 1f located between the capacitor element 1b and the capacitor module cooling flow path 1e, all the heat generated by each phase power semiconductor module 4U, 4V, 4W is dissipated by the power semiconductor module cooler 3, and the heat flowing into the capacitor module 1 via the water jacket 1g made of synthetic resin is eliminated, thereby achieving cooling of the capacitor element 1b by the capacitor module cooling flow paths 1e and 1h. As a result, the capacitor element 1b can be prevented from being heated by the heat generated by each phase power semiconductor module 4U, 4V, 4W, thereby enabling miniaturization of the capacitor module 1.

[0101] Furthermore, in the power conversion device according to Embodiment 4, each phase current sensor 5b and each phase power semiconductor module 4U, 4V, 4W are thermally bonded to the power semiconductor module cooler 3. However, if the output power is small and the heat generation in each phase current sensor 5b is small, the same effect as described above can be obtained even if each phase current sensor 5b is not thermally bonded to the power semiconductor module cooler 3.

[0102] Furthermore, in the power conversion device according to Embodiment 4, the water jacket 1g made of synthetic resin and the synthetic resin 1f of the capacitor module 1 are set as different components, but they can also be configured as an integral structure using synthetic resin, in which case the same effect as described above can be obtained.

[0103] Furthermore, in the power conversion device according to Embodiment 4, the connecting bus 1d and the output bus 5a are metal busbars, but conductive components such as cables and wiring boards can also be used instead of metal busbars, and the same effect as described above can be obtained in this case.

[0104] Furthermore, according to the power conversion device of embodiment 4, since the heat generated by the discharge unit 1k used to discharge the residual charge of the capacitor module 1 can be dissipated in the planar direction of the wiring board 1c, the discharge unit 1k can be miniaturized. Since the heat generated by the discharge unit 1k is not conducted to the capacitor element 1b, the capacitor element 1b can be prevented from being heated, thereby miniaturizing the capacitor module 1.

[0105] Implementation method 5.

[0106] Next, the power conversion device according to Embodiment 5 will be described. Figure 8 It is along Figure 1A cross-sectional view of the power conversion device according to Embodiment 5, viewed from the direction of arrow S at the section of line AA. Figure 1 and Figure 8 In the capacitor module 1, there are: a capacitor housing 1a; a capacitor element 1b housed in the capacitor housing 1a; a flat wiring board 1c housed in the capacitor housing 1a and spaced apart from the upper surface of the capacitor element 1b; and a connecting bus 1d, the end of which is housed in the capacitor housing 1a and is connected to the wiring board 1c by welding or brazing.

[0107] In addition, capacitor module 1 includes: synthetic resin 1f, which fills the internal space of capacitor housing 1a and embeds a portion of capacitor element 1b, wiring board 1c and connecting busbar 1d; and water jacket 1g, which is placed on the upper surface of capacitor housing 1a and is formed of synthetic resin.

[0108] The discharge unit 1k that discharges the residual charge of capacitor element 1b is disposed on the side of capacitor module 1 near the cooling flow paths 1e and 1h of capacitor module.

[0109] The power conversion device 500 according to Embodiment 5 is configured such that the combined equivalent thermal resistance Rtha [K / W] of the water jacket 1g, synthetic resin 1f and wiring board 1c made of synthetic resin located between the power semiconductor modules 4U, 4V, 4W and the capacitor element 1b is greater than the thermal resistance Rthb [K / W] of the synthetic resin 1f located between the capacitor element 1b and the cooling flow paths 1e, 1h of the capacitor module.

[0110] As a specific means to make the above-mentioned equivalent thermal resistance Rtha [K / W] greater than the thermal resistance Rthb [K / W] of the synthetic resin 1f, there is a so-called material factor-based method. This method selects the materials of each synthetic resin and the wiring board so that the thermal resistance of the synthetic resin 1f located between the capacitor element 1b and the cooling flow paths 1e and 1h of the capacitor module is smaller than the thermal resistance of the synthetic resin constituting the water jacket 1g, the thermal resistance of the synthetic resin 1f located between the capacitor element 1b and the water jacket 1g, and the thermal resistance of the wiring board 1c.

[0111] In addition to the above-mentioned material-based method, a so-called structural-based method can also be used, in which the thickness of the synthetic resin 1f located between the capacitor element 1b and the water jacket 1g and the thickness of the wiring board 1c are combined to obtain a thickness that is greater than the thickness of the synthetic resin 1f located between the capacitor element 1b and the capacitor module cooling flow paths 1e and 1h.

[0112] The other structures of the power conversion device involved in Embodiment 5 are the same as those of the power conversion device in Embodiment 1 described above.

[0113] According to the power conversion device of Embodiment 5 as described above, since the combined equivalent thermal resistance Rtha of the structural elements configured between each phase power semiconductor module 4U, 4V, 4W and the capacitor element 1b—namely, the water jacket 1g made of synthetic resin, the synthetic resin 1f, and the wiring board 1c—is greater than the thermal resistance Rthb of the synthetic resin 1f located between the capacitor element 1b and the capacitor module cooling flow path 1e, all the heat generated by each phase power semiconductor module 4U, 4V, 4W is dissipated by the power semiconductor module cooler 3, and the heat flowing into the capacitor module 1 via the water jacket 1g made of synthetic resin is eliminated, thereby achieving cooling of the capacitor element 1b by the capacitor module cooling flow paths 1e and 1h. As a result, the capacitor element 1b can be prevented from being heated by the heat generated by each phase power semiconductor module 4U, 4V, 4W, thereby enabling miniaturization of the capacitor module 1.

[0114] Furthermore, according to the power conversion device of Embodiment 5, since the discharge unit 1k for discharging the residual charge of the capacitor module 1 is arranged on the side of the capacitor module 1 close to the capacitor module cooling flow path 1e, 1h, the heat generated by the discharge unit 1k is dissipated by the capacitor module cooling flow path 1e, 1h, so the discharge unit 1k can be miniaturized. And since the heat generated by the discharge unit 1k can be prevented from being conducted to the capacitor element 1b, the capacitor element 1b can be prevented from being heated, thereby realizing the miniaturization of the capacitor module 1.

[0115] Furthermore, in the power conversion device according to Embodiment 5, each phase current sensor 5b and each phase power semiconductor module 4U, 4V, 4W are thermally connected to the power semiconductor module cooler 3. However, if the output power is small and the heat generation in each phase current sensor 5b is small, the same effect as described above can be obtained even if each phase current sensor 5b is not thermally connected to the power semiconductor module cooler 3.

[0116] Furthermore, in the power conversion device according to Embodiment 5, the water jacket 1g made of synthetic resin and the synthetic resin 1f of the capacitor module 1 are set as different components, but they can also be configured as an integral structure using synthetic resin, in which case the same effect as described above can be obtained.

[0117] Furthermore, in the power conversion device according to Embodiment 5, the connecting bus 1d and the output bus 5a are metal busbars, but conductive components such as cables and wiring boards can also be used instead of metal busbars, and the same effect as described above can be obtained in this case.

[0118] Implementation method 6.

[0119] Next, the power conversion device according to Embodiment 6 will be described. Figure 9 It is along Figure 1 A cross-sectional view of the power conversion device according to Embodiment 6, viewed from the direction of arrow S at the section of line AA. Figure 1 and Figure 9 In this configuration, the busbar assembly 5 integrates three output buses 5a corresponding to phases U, V, and W, respectively, with current sensors 5b for phases U, V, and W installed on these output buses 5a. The three output buses 5a corresponding to phases U, V, and W are connected to the respective AC terminals 42 of the power semiconductor modules 4U, 4V, and 4W for each phase.

[0120] Three output buses 5a, corresponding to phases U, V, and W respectively, extend parallel to the upper surface of the power semiconductor module cooler 3 at intervals, and are bent along the side of the water jacket 1g and the side of the capacitor housing 1a at intervals. Each phase current sensor 5b is provided on each output bus 5a, and the bottom part of the current sensor 5b is fixed to the side of the capacitor housing 1a near the capacitor module cooling flow paths 1e and 1h.

[0121] The power conversion device 600 according to Embodiment 6 is configured such that the combined equivalent thermal resistance Rtha [K / W] of the water jacket 1g, synthetic resin 1f and wiring board 1c made of synthetic resin located between the power semiconductor modules 4U, 4V, 4W and the capacitor element 1b is greater than the thermal resistance Rthb [K / W] of the synthetic resin 1f located between the capacitor element 1b and the cooling flow paths 1e, 1h of the capacitor module.

[0122] As a specific means to make the above-mentioned equivalent thermal resistance Rtha [K / W] greater than the thermal resistance Rthb [K / W] of the synthetic resin 1f, there is a so-called material factor-based method. This method selects the materials of each synthetic resin and the wiring board so that the thermal resistance of the synthetic resin 1f located between the capacitor element 1b and the cooling flow paths 1e and 1h of the capacitor module is smaller than the thermal resistance of the synthetic resin constituting the water jacket 1g, the thermal resistance of the synthetic resin 1f located between the capacitor element 1b and the water jacket 1g, and the thermal resistance of the wiring board 1c.

[0123] In addition to the material-based method mentioned above, a so-called structural-based method can also be used, in which the thickness of the synthetic resin constituting the water jacket 1g, the thickness of the synthetic resin 1f located between the capacitor element 1b and the water jacket 1g, and the thickness of the wiring board 1c are combined to obtain a thickness greater than the thickness of the synthetic resin 1f located between the capacitor element 1b and the capacitor module cooling flow paths 1e and 1h.

[0124] According to the power conversion device of Embodiment 6 as described above, since the combined equivalent thermal resistance Rtha of the structural elements configured between each phase power semiconductor module 4U, 4V, 4W and the capacitor element 1b—namely, the water jacket 1g made of synthetic resin, the synthetic resin 1f, and the wiring board 1c—is greater than the thermal resistance Rthb of the synthetic resin 1f located between the capacitor element 1b and the capacitor module cooling flow path 1e, all the heat generated by each phase power semiconductor module 4U, 4V, 4W is dissipated by the power semiconductor module cooler 3, and the heat flowing into the capacitor module 1 via the water jacket 1g made of synthetic resin is eliminated, thereby enabling the cooling of the capacitor element 1b by the capacitor module cooling flow paths 1e and 1h. As a result, the capacitor element 1b can be prevented from being heated by the heat generated by each phase power semiconductor module 4U, 4V, 4W, thereby enabling the miniaturization of the capacitor module 1.

[0125] Furthermore, in the power conversion device according to Embodiment 6, the water jacket 1g made of synthetic resin and the synthetic resin 1f of the capacitor module 1 are set as different components, but they can also be configured as an integral structure using synthetic resin, in which case the same effect as described above can be obtained.

[0126] Furthermore, in the power conversion device according to Embodiment 6, the connecting bus 1d and the output bus 5a are metal busbars, but conductive components such as cables and wiring boards can also be used instead of metal busbars, and the same effect as described above can be obtained in this case.

[0127] Furthermore, according to the power conversion device of embodiment 6, since the current sensor 5b is disposed on the side of the capacitor module 1 near the capacitor module cooling flow path 1e, 1h, the heat generated by it is dissipated by the capacitor module cooling flow path 1e, 1h, thereby enabling the current sensor 5b to be miniaturized. Moreover, since the heat generated by the current sensor 5b can be prevented from being conducted to the capacitor element 1b, the capacitor module 1 can be miniaturized.

[0128] This disclosure describes various exemplary embodiments and examples, but the various features, forms, and functions described in one or more embodiments are not limited to the application of a specific embodiment and can be applied to the embodiments individually or in various combinations. Therefore, it can be considered that numerous modifications not illustrated are also included within the scope of the technology disclosed in this application. For example, this includes cases where at least one structural element is modified, added to, or omitted, and cases where at least one structural element is extracted and combined with structural elements of other embodiments.

[0129] Label Explanation

[0130] 100, 200, 300, 400, 500, 600 Power conversion device; 101 Refrigerant inlet port; 102 Refrigerant outlet port; 1 Capacitor module; 1a Capacitor housing; 1b Capacitor element; 1c Wiring board; 1d Connecting bus; 1e, 1h, 1i, 1j Capacitor module cooling flow path; 1f Synthetic resin; 1g, 1gi Water jacket; 1k Discharge unit; 11 Upper surface; 12 Bottom surface; 13 First side surface; 14 Second side surface; 15 Third side surface; 16 Fourth side surface; 2 Power semiconductor module cooling flow path; 3 Power semiconductor module cooler; 4U U-phase power semiconductor module; 4V V-phase power semiconductor module; 4W W-phase power semiconductor module; 41 Positive DC terminal; 42 AC terminal; 5 Busbar assembly; 5a Output bus; 5b Current sensor.

Claims

1. A power conversion device comprising a power conversion circuit composed of a plurality of power semiconductor elements, wherein power conversion between DC power and AC power is performed by switching action of the power semiconductor elements, the power conversion device being characterized in that it includes: A power semiconductor module, the power semiconductor module having the power semiconductor element; A power semiconductor module cooler for cooling the power semiconductor module; as well as A capacitor module, connected to the DC terminal of the power conversion circuit, includes capacitor elements that smooth the voltage and current at the DC terminal. The capacitor module has: A capacitor housing that houses the capacitor element; A wiring board housed in the capacitor housing; A capacitor module cooling flow path, which is housed in the capacitor housing, cools the capacitor element; as well as The sleeve, in combination with the power semiconductor module cooler, forms a power semiconductor module cooling flow path for cooling the power semiconductor module. The cooling path of the power semiconductor module is interconnected with the cooling path of the capacitor module. The thermal resistance between the power semiconductor module and the capacitor element is configured to be greater than the thermal resistance between the capacitor element and the cooling flow path of the capacitor module.

2. The power conversion device as described in claim 1, characterized in that, The sleeve is formed of synthetic resin.

3. The power conversion device as described in claim 1, characterized in that, The sleeve is made of metal.

4. The power conversion device according to any one of claims 1 to 3, characterized in that, The capacitor module cooling flow path is configured to cool multiple surfaces of the capacitor element.

5. The power conversion device according to any one of claims 1 to 4, characterized in that, The cooling flow path of the capacitor module includes a portion disposed opposite to the bottom surface of the capacitor module. The capacitor module has a refrigerant input / output unit on the bottom surface of the capacitor housing opposite to the bottom surface of the capacitor module. The capacitor module cooling flow path is configured to allow the refrigerant to be input and output relative to the external environment of the capacitor module via a refrigerant input / output unit.

6. The power conversion device according to any one of claims 1 to 5, characterized in that, It includes a current sensor that detects the current at the AC terminals of the power semiconductor module. The current sensor and the AC terminal are integrated into one unit.

7. The power conversion device as described in claim 6, characterized in that, The current sensor is mounted on the power semiconductor module cooler.

8. The power conversion device as described in claim 6, characterized in that, The current sensor is disposed on the side of the capacitor housing, which is the side corresponding to the cooling flow path of the capacitor module.

9. The power conversion device according to any one of claims 1 to 8, characterized in that, It includes a discharge unit that discharges the charge from the capacitor element. The discharge unit is disposed on the wiring board.

10. The power conversion device according to any one of claims 1 to 8, characterized in that, It includes a discharge unit that discharges the charge from the capacitor element. The discharge unit is disposed on the side of the capacitor housing.

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