Power conversion device, and electronic device

Abstract

A power conversion device (100) comprises: arm elements (11, 12); metal heat sinks (120, 130) to which the arm elements (11, 12) are attached; a resin frame part (140) that forms, together with the heat sinks (120, 130), a refrigerant flow path (145) through which a refrigerant (170) flows; and a metal housing (110). The heat sinks (120, 130) are provided such that the refrigerant (170) is disposed between the heat sinks (120, 130) and the housing (110). The heat sinks (120, 130) and the housing (110) are electrically connected.

Description

Power conversion devices and electronic devices CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Patent Application No. 2024-129757 filed in Japan on August 6, 2024, the contents of which are incorporated by reference in their entirety.

[0002] The present disclosure relates to power conversion devices and electronic devices.

[0003] An example of a power conversion device is an inverter disclosed in Patent Document 1. The inverter includes an insulating substrate, electrode conductors provided on the surface of the substrate, and switching elements mounted on the electrode conductors. The substrate is joined to a heat sink made of an aluminum alloy. The heat sink is also made of an aluminum alloy and is attached to a cooler having a flow path through which a refrigerant flows. Furthermore, the inverter has a fitting portion that electrically insulates the heat sink from the cooler.

[0004] JP 2024-15807 A

[0005] In a power conversion device, a refrigerant is disposed between a heat sink and a cooler, and therefore, if a potential difference occurs between the heat sink and the cooler, the refrigerant may be electrolyzed.

[0006] One disclosed object is to provide a power conversion device that can suppress electrolysis of a refrigerant. Another disclosed object is to provide an electronic device that can suppress electrolysis of a refrigerant.

[0007] The power conversion device disclosed herein comprises at least one electronic component, at least one first metal part to which the electronic component is attached, and a resin frame part that, together with the first metal part, forms a refrigerant flow path through which a refrigerant flows, wherein the first metal part is provided with a refrigerant disposed between it and the second metal part, and the first metal part and the second metal part are electrically connected.

[0008] This allows the power conversion device to prevent a potential difference from being applied to the refrigerant disposed between the first metal part and the second metal part, thereby preventing the refrigerant from being electrolyzed.

[0009] The electronic device disclosed herein is an electronic device comprising at least one electronic component, at least one first metal part to which the electronic component is attached, and a resin frame part which, together with the first metal part, forms a refrigerant flow path through which a refrigerant flows, wherein the first metal part is provided with a refrigerant disposed between it and the second metal part, and the first metal part and the second metal part are electrically connected.

[0010] The electronic device can achieve the same effects as the power conversion device.

[0011] The various aspects disclosed in this specification employ different technical means to achieve their respective objectives. The reference numerals in parentheses in the claims and in this section indicate examples of correspondences with the embodiments described below, and are not intended to limit the technical scope. The objectives, features, and advantages disclosed in this specification will become clearer by referring to the following detailed description and the accompanying drawings.

[0012] 9 is a circuit diagram showing a schematic configuration of a power conversion device. FIG. 10 is a plan view showing a schematic configuration of a converter circuit. FIG. 11 is a cross-sectional view taken along line III-III in FIG. 2. FIG. 12 is a plan view showing a schematic configuration of a resin frame. FIG. 13 is an equivalent circuit diagram between a switching element and a housing. FIG. 14 is a cross-sectional view showing a schematic configuration of a converter circuit of a second embodiment. FIG. 15 is an equivalent circuit diagram between switching elements. FIG. 16 is a cross-sectional view showing a schematic configuration of a converter circuit of Modified Example 1. FIG. 17 is a plan view showing a schematic configuration of upper and lower arm circuits of a third embodiment. FIG. 18 is a cross-sectional view taken along line X-X in FIG. 9. FIG. 19 is a plan view showing a schematic configuration of upper and lower arm circuits of Modified Example 2.

[0013] Hereinafter, several embodiments for carrying out the present disclosure will be described with reference to the drawings. In each embodiment, parts corresponding to matters described in the preceding embodiment may be assigned the same reference numerals, and duplicated explanations may be omitted. In each embodiment, when only a part of the configuration is described, the other parts of the configuration may be applied by referring to the other embodiment described previously.

[0014] First Embodiment A power conversion device 100 according to this embodiment will be described with reference to Figures 1 to 5. As shown in Figure 1, the power conversion device 100 is configured to be connectable between a battery 200 and a motor 300. The battery 200 is a DC power supply. The battery 200 has a positive electrode and a negative electrode. The motor 300 is a three-phase AC motor. The motor 300 has a U-phase coil, a V-phase coil, a W-phase coil, and the like.

[0015] The power conversion device 100 is configured to be mountable on, for example, a mobile object. Examples of the mobile object include vehicles such as electric cars, hybrid cars, and fuel cell cars, flying objects such as electric vertical take-off and landing aircraft and drones, ships, construction machinery, agricultural machinery, etc. However, the power conversion device 100 can also be mounted on devices other than mobile objects.

[0016] <Circuit Configuration of Power Conversion Device> The power conversion device 100 includes a boost converter circuit 10 and an inverter circuit 20. The power conversion device 100 also includes smoothing capacitors 41 and 42. Furthermore, the power conversion device 100 includes, as wiring sections, low-voltage system lines 31 and 32, high-voltage system lines 33 and 34, and phase output lines 35 to 37.

[0017] The low-voltage lines 31 and 32 are power wirings provided mainly in the upstream stage of the boost converter circuit 10. The low-voltage P line 31 is connected to the positive electrode of the battery 200 and the boost converter circuit 10. The low-voltage N line 32 is connected to the negative electrode of the battery 200 and the boost converter circuit 10. The smoothing capacitor 41 is connected to the low-voltage P line 31 and the low-voltage N line 32.

[0018] The high-voltage lines 33 and 34 are power wirings provided mainly in the subsequent stage of the boost converter circuit 10. The high-voltage P line 33 is connected to the high-potential side of the boost converter circuit 10. The high-voltage N line 34 is connected to the low-potential side of the boost converter circuit 10. The smoothing capacitor 42 is connected to the high-voltage P line 33 and the high-voltage N line 34.

[0019] The phase output lines 35 to 37 are output wirings provided between the inverter circuit 20 and the motor 300. The U-phase output line 35 is connected to the connection point between the U-phase upper arm element 21 and the U-phase lower arm element 22, which will be described later, and to the U-phase coil. The V-phase output line 36 is connected to the connection point between the V-phase upper arm element 23 and the V-phase lower arm element 24, which will be described later, and to the V-phase coil. The W-phase output line 37 is connected to the connection point between the W-phase upper arm element 25 and the W-phase lower arm element 26, which will be described later, and to the W-phase coil.

[0020] The boost converter circuit 10 includes an upper arm element 11, a lower arm element 12, and a coil 13. The upper arm element 11 and the lower arm element 12 correspond to electronic components. In this embodiment, semiconductor switching elements are used as the upper arm element 11 and the lower arm element 12. In this embodiment, an IGBT is used as an example of the semiconductor switching element. IGBT is an abbreviation for Insulated Gate Bipolar Transistor. However, the semiconductor switching element may also be a MOSFET or the like.

[0021] The upper arm element 11 and the lower arm element 12 are connected in series between a high-voltage P line 33 and a high-voltage N line 34. The collector electrode of the upper arm element 11 is connected to the high-voltage P line 33. The emitter electrode of the lower arm element 12 is connected to the high-voltage N line 34 (low-voltage N line 32).

[0022] The emitter electrode of the upper arm element 11 is connected to the collector electrode of the lower arm element 12. The point where the emitter electrode of the upper arm element 11 and the collector electrode of the lower arm element 12 are connected corresponds to the connection point between the upper arm element 11 and the lower arm element 12. The connection point between the upper arm element 11 and the lower arm element 12 is connected to the positive electrode of the battery 200 via the coil 13 and the low-voltage system P line 31.

[0023] The inverter circuit 20 includes a U-phase upper and lower arm circuit 20u, a V-phase upper and lower arm circuit 20v, and a W-phase upper and lower arm circuit 20w. The U-phase upper and lower arm circuit 20u includes a U-phase upper arm element 21 and a U-phase lower arm element 22. The V-phase upper and lower arm circuit 20v includes a V-phase upper arm element 23 and a V-phase lower arm element 24. The W-phase upper and lower arm circuit 20w includes a W-phase upper arm element 25 and a W-phase lower arm element 26.

[0024] Each of the phase arm elements 21 to 26 is a semiconductor switching element. In this embodiment, an IGBT is used as an example of each of the phase arm elements 21 to 26. However, each of the phase arm elements 21 to 26 may also be a MOSFET or the like. Each of the phase arm elements 21 to 26 can also be considered as a circuit component.

[0025] U-phase upper arm element 21 and U-phase lower arm element 22 are connected in series between high voltage P line 33 and high voltage N line 34. The collector electrode of U-phase upper arm element 21 is connected to high voltage P line 33. The emitter electrode of U-phase lower arm element 22 is connected to high voltage N line 34.

[0026] The emitter electrode of the U-phase upper arm element 21 is connected to the collector electrode of the U-phase lower arm element 22. The point at which the emitter electrode of the U-phase upper arm element 21 and the collector electrode of the U-phase lower arm element 22 are connected corresponds to the connection point between the U-phase upper arm element 21 and the U-phase lower arm element 22. The connection point between the U-phase upper arm element 21 and the U-phase lower arm element 22 is connected to the U-phase output line 35. The same applies to the V-phase upper and lower arm circuit 20v and the W-phase upper and lower arm circuit 20w.

[0027] <Structure of Power Conversion Device> The structure of the power conversion device 100 will now be described with reference to Figures 2 to 4. For convenience, Figures 2 to 4 show only a portion of the power conversion device 100. That is, Figures 2 and 3 show the portion where the arm elements 11 and 12 are provided. Figure 4 shows the portion of the resin frame 140 that corresponds to the arm elements 11 and 12. Note that, to avoid complication of the drawings, Figures 2 and 3 omit terminals connected to the electrodes 11e and 12e of the arm elements 11 and 12, buses that are part of the wiring, and the like.

[0028] 2 and 3, the power conversion device 100 includes circuit elements such as the above-mentioned coil 13, the arm elements 21 to 26 of each phase, and smoothing capacitors 41 and 42 in addition to the arm elements 11 and 12. The power conversion device 100 includes a housing 110 in which the circuit elements are mounted, heat sinks 120 and 130 that are part of a cooler that cools the arm elements 11 and 12, and a resin frame 140. The power conversion device 100 also includes an insulator 150 that electrically insulates the electrodes 11e and 12e from the heat sinks 120 and 130. The insulator 150 is also referred to as an insulating material.

[0029] 2 and 3, the housing 110 includes a housing base 111, attachment portions 112 and 113, a mounting portion 114, and a flow path forming portion 115. For example, the housing base 111, attachment portions 112 and 113, the mounting portion 114, and the flow path forming portion 115 are configured as a single unit. The housing 110 also includes a second flow path 116. The housing 110 is a conductive member whose main component is a metal such as aluminum or copper.

[0030] The housing 110 is connected to the ground potential. In addition, the housing 110 can also be considered a member having the ground potential. In this embodiment, the housing 110 corresponds to the second metal part. Therefore, it can be said that the power conversion device 100 includes the housing 110, which is the second metal part.

[0031] The mounting portion 112 is provided on the housing base 111. The mounting portion 112 is a portion to which the heat sinks 120 and 130 are attached. The mounting portion 112 is provided with a female thread that corresponds to the male thread of the bolt 1. The bolt 1 is a conductive screw member whose main component is metal.

[0032] The mounting portion 113 is provided on the housing base 111. The mounting portion 113 is a portion to which the resin frame 140 is attached. The mounting portion 113 is provided with a female thread that corresponds to the male thread of the bolt 2.

[0033] The mounting portion 114 is provided on the housing base 111. The mounting portion 114 is a portion on which the smoothing capacitor 41 is mounted. The smoothing capacitor 41 is mounted on the mounting portion 114 via an insulator 150 that has electrical insulation properties. The mounting portion 114 is also provided with a second flow path 116, which is a flow path through which a refrigerant flows. The second flow path 116 is provided to cool the smoothing capacitor 41. The second flow path 116 communicates with the first flow path 145 via a connecting flow path 160.

[0034] Therefore, the housing 110 can also be said to be a cooler that cools the smoothing capacitor 41. The second flow path 116 corresponds to the other refrigerant flow path. The smoothing capacitor 41 corresponds to the other electronic component. Note that the other electronic component is not limited to the smoothing capacitor 41. The other electronic component may be another capacitor, the coil 13, or the like.

[0035] The coolant 170 may be, for example, a long-life coolant (LLC), which may contain, for example, ethylene glycol or propylene glycol.

[0036] The flow path forming portion 115 is provided in the housing base portion 111. The flow path forming portion 115 is provided with an inflow path 115h for the coolant. The inflow path 115h is a flow path for flowing the coolant from the outside of the housing 110 into the first flow path 145.

[0037] In addition to the arm elements 11 and 12 and the smoothing capacitor 41, the housing 110 may also be equipped with circuit elements such as the coil 13, the arm elements 21 to 26 for each phase, and a smoothing capacitor 42.

[0038] 2 and 3 , the first heat sink 120 is disposed in the resin frame 140 so as to cover an opening 144 of the resin frame 140, which will be described later. The first heat sink 120 is a conductive member whose main component is a metal such as aluminum or copper. The first heat sink 120 includes a heat sink base 121, an extension 122, and heat dissipation fins 123. The heat sink base 121, the extension 122, and the heat dissipation fins 123 are provided as a single unit.

[0039] The heat sink base 121 is a plate-shaped member. The heat sink base 121 includes a portion where the upper arm element 11 is attached. In other words, the upper arm element 11 is mounted on one surface of the heat sink base 121. The heat sink base 121 is a portion that corresponds to the opposing region of the upper arm element 11.

[0040] The extension portion 122 is a portion that extends from the heat sink base 121. The extension portion 122 is a portion that extends from the heat sink base 121 in the opposite direction to the second heat sink 130. The extension portion 122 is provided to connect the first heat sink 120 and the housing 110. The extension portion 122 is a plate-like member, similar to the heat sink base 121. The extension portion 122 can also be considered to be part of the heat sink base 121.

[0041] The heat dissipation fins 123 are provided to protrude from the heat sink base 121. The heat dissipation fins 123 are provided on the side of the heat sink base 121 opposite the upper arm element 11. In other words, the heat dissipation fins 123 are provided on the opposite side of one surface of the heat sink base 121. The heat dissipation fins 123 are arranged in a first flow path 145, which will be described later, with the first heat sink 120 arranged in the resin frame 140. In other words, the heat dissipation fins 123 are exposed to the refrigerant flowing through the first flow path 145.

[0042] The second heat sink 130 includes a heat sink base 131, an extension 132, and heat dissipation fins 133. The second heat sink 130 is made of the same materials as the first heat sink 120. The second heat sink 130 has the same shape as the first heat sink 120. The lower arm element 12 is attached to the second heat sink 130. The extension 132 is a portion that extends from the heat sink base 131 in the opposite direction to the first heat sink 120.

[0043] 3 , the heat sinks 120 and 130 are attached to the resin frame 140 so as to close the opening 144. The heat sinks 120 and 130 are attached to the resin frame 140 with the heat dissipation fins 123 and 133 disposed in the first flow path 145.

[0044] As will be explained later, in the power conversion device 100, the heat sinks 120, 130 and the resin frame 140 form a first flow path 145 through which the refrigerant 170 flows. Therefore, the heat sinks 120, 130 and the resin frame 140 are tightly fixed to each other so as to prevent leakage of the refrigerant 170. It can be said that the heat sinks 120, 130 are attached to the resin frame 140 in a watertight state.

[0045] The heat sinks 120 and 130 are attached to the mounting portion 112 of the housing 110. The heat sinks 120 and 130 are attached to the mounting portion 112 with bolts 1. In other words, the heat sinks 120 and 130 and the mounting portion 112 are fastened together with the bolts 1. It can also be said that the heat sinks 120 and 130 are fixed to the housing 110 by the bolts 1.

[0046] The mounting portion 112 and the heat sinks 120 and 130 are electrically connected via bolts 1. Alternatively, the mounting portion 112 and the heat sinks 120 and 130 may be electrically connected directly. In this manner, the heat sinks 120 and 130 are electrically connected to the housing 110.

[0047] Each of the heat sinks 120 and 130 is fixed to the housing 110 at two locations. However, the present disclosure is not limited to this. Each of the heat sinks 120 and 130 may be fixed to the housing 110 at one location or at three or more locations.

[0048] In this embodiment, the heat sinks 120 and 130 correspond to the first metal portion. Therefore, this embodiment employs an example in which two first metal portions to which electronic components are attached are provided. However, the present disclosure only requires that at least one first metal portion to which an electronic component is attached be provided.

[0049] The arm elements 11 and 12 each include a semiconductor switching element and a resin protective member that exposes electrodes 11e and 12e of the semiconductor switching element. The resin protective member has electrical insulation properties. The arm elements 11 and 12 are arranged such that the electrodes 11e and 12e face the heat sinks 120 and 130. In other words, the power conversion device 100 has the arm elements 11 and 12 arranged flat. The electrodes 11e and 12e are at the same potential.

[0050] The upper arm element 11 is attached to the heat sink base 121 via an insulator 150. An electrode 11e is exposed on the surface of the upper arm element 11 facing the heat sink base 121. The insulator 150 is provided between the electrode 11e and the heat sink base 121. In other words, the upper arm element 11 is attached to the first heat sink 120 via the insulator 150. Therefore, the electrode 11e is electrically insulated from the heat sink base 121 by the insulator 150.

[0051] The lower arm element 12 is attached to the heat sink base 131 via an insulator 150. An electrode 12e of the lower arm element 12 is exposed on the surface facing the heat sink base 131. The insulator 150 is provided between the electrode 12e and the heat sink base 131. In other words, the lower arm element 12 is attached to the second heat sink 130 via the insulator 150. Therefore, the electrode 12e is electrically insulated from the heat sink base 131 by the insulator 150.

[0052] Arm elements 11 and 12 generate heat when they operate. Therefore, arm elements 11 and 12 are cooled by refrigerant 170 via heat sinks 120 and 130. Arm elements 11 and 12 can also be considered electronic components having a potential equal to or greater than a predetermined value relative to refrigerant 170. On the other hand, housing 110 can also be considered a member whose potential difference with refrigerant 170 is smaller than the predetermined value. The predetermined potential is, for example, 1.23 V.

[0053] The arm elements 11 and 12 are IGBTs, and therefore each arm element 11 and 12 has electrodes other than the electrodes 11e and 12e, although these other electrodes are not shown in the present embodiment.

[0054] The arm elements 11 and 12 may be disposed so that the resin protective member faces the heat sinks 120 and 130. In this case, the resin protective member can be regarded as the insulator 150.

[0055] Each of the phase arm elements 21 to 26 may be attached to a heat sink via an insulator 150, similar to the arm elements 11 and 12. The heat sink to which each of the phase arm elements 21 to 26 is attached is also referred to as a phase heat sink. Two of the phase arm elements 21 to 26 may be attached to heat sinks 120 and 130, respectively, instead of the arm elements 11 and 12.

[0056] 2, 3, and 4, the resin frame 140 includes a frame base 141, a mounting portion 142, a bottom 143, and a fixing portion 146. The frame base 141, the mounting portion 142, the bottom 143, and the fixing portion 146 may be configured as a single unit, or may be configured from multiple members, for example.

[0057] The resin frame 140, together with the heat sinks 120 and 130, is a member that forms a first flow path 145 through which the refrigerant 170 flows. Parts of the resin frame 140 and parts of the heat sinks 120 and 130 come into contact with the refrigerant 170. The resin frame 140 is a member whose main component is an electrically insulating resin.

[0058] 3, a portion of the frame base 141 is disposed opposite the bottom 143 with a gap therebetween. The frame base 141 and the bottom 143 form a space that serves as a first flow path 145 through which the refrigerant 170 flows. The frame base 141 has an opening 144 in which the heat dissipation fins 133 are disposed in a portion of the portion that faces the bottom 143. The mounting portion 142 is a portion of the frame base 141. The mounting portion 142 is a portion to which the heat sinks 120 and 130 are attached.

[0059] 4, the frame base 141 is provided with an outlet 142h for the coolant 170. The outlet 142h is a through-hole provided in the frame base 141. A connecting flow path 160 is attached to the outlet 142h.

[0060] The bottom 143 is provided with an inlet 143h for the coolant 170. The inlet 143h is a through-hole provided in the bottom 143. When the resin frame 140 is placed in the housing 110, the inlet 143h is disposed opposite the inlet channel 115h.

[0061] Therefore, the coolant 170 flows from the inlet 115h through the inlet 143h into the first flow path 145. The coolant 170 then flows from the first flow path 145 through the outlet 142h into the connecting flow path 160. The coolant 170 then flows from the connecting flow path 160 into the second flow path 116.

[0062] In the present embodiment, as an example, the coolant 170 flows from the first flow path 145 to the second flow path 116. However, the power conversion device 100 may be configured so that the coolant 170 flows from the second flow path 116 to the first flow path 145.

[0063] The fixing portion 146 is a portion that is fixed to the housing 110. As shown in Fig. 4, the fixing portion 146 is provided with a through hole 146h into which the bolt 2 is inserted. The through hole 146h is disposed opposite the female thread of the mounting portion 113. In this embodiment, as an example, an example is adopted in which a reinforcing collar 146c is provided in the through hole. However, the collar 146c does not have to be provided.

[0064] The fixing portion 146 of the resin frame portion 140 is disposed on the mounting portion 113. The fixing portion 146 of the resin frame portion 140 is fixed to the mounting portion 113 by the bolt 2. In other words, the resin frame portion 140 and the housing 110 are fastened together by the bolt 2. It can also be said that the resin frame portion 140 is fixed to the housing 110 by the bolt 2. The resin frame portion 140 is fixed to the housing 110 with the bottom portion 143 disposed opposite the housing base 111.

[0065] The resin frame 140 is fixed to the housing 110 at four locations. However, the present disclosure is not limited to this. It is sufficient that the resin frame 140 is fixed to the housing 110 at at least two locations.

[0066] 3, the heat sinks 120 and 130 are attached to the resin frame 140 so as to close the opening 144. The resin frame 140 and the heat sinks 120 and 130 form a first flow path 145 through which the refrigerant 170 flows. In other words, the first flow path 145 is surrounded by the frame base 141, the bottom 143, and the heat sinks 120 and 130. The first flow path 145 corresponds to a refrigerant flow path.

[0067] Arm elements 11 and 12 are mounted on heat sinks 120 and 130. Therefore, arm elements 11 and 12 are cooled by refrigerant 170 via heat sinks 120 and 130. Therefore, it can be said that resin frame 140, together with heat sinks 120 and 130, constitutes a cooler that cools arm elements 11 and 12. In other words, it can be said that the cooler for arm elements 11 and 12 is composed of metal members and resin members.

[0068] Therefore, the power conversion device 100 can be made lighter than a configuration including a cooler whose entire body is made primarily of metal. Furthermore, the resin frame 140, which is part of the cooler, of the power conversion device 100 can be recycled. Therefore, it is preferable that the resin frame 140 be made of a recyclable material.

[0069] In the power conversion device 100, both the upper arm element 11 and the lower arm element 12 are attached to the cooler. However, in the power conversion device 100, one electronic component, for example, one of the upper arm element 11 and the lower arm element 12, may be attached to the cooler.

[0070] The resin frame 140 may be configured to allow the heat sinks of each phase to be attached. That is, the resin frame 140 may form a cooler together with the heat sinks of each phase. Furthermore, in addition to the resin frame 140, the power conversion device 100 may include resin frames for the arm elements 21 to 26 of each phase, each having a similar configuration to the resin frame 140.

[0071] Here, the positional relationship of the components of the power conversion device 100 will be summarized. As shown in Fig. 3, the arm elements 11 and 12 are mounted on one surface of the heat sinks 120 and 130. On the other hand, a first flow path 145 is provided on the opposite surface of the heat sinks 120 and 130.

[0072] That is, the coolant 170 flows on the opposite side of the heat sinks 120 and 130. In other words, the coolant 170 is disposed on the opposite side of the heat sinks 120 and 130.

[0073] The opposite surfaces of the heat sinks 120, 130 face the bottom 143. More specifically, the opposite surfaces of the heat sinks 120, 130 face the flow path forming surface of the bottom 143 that forms the first flow path 145. Therefore, the refrigerant 170 is disposed between the opposite surfaces of the heat sinks 120, 130 and the bottom 143.

[0074] Furthermore, the bottom 143 faces the housing base 111. More specifically, the surface of the bottom 143 opposite the flow path forming surface faces the housing base 111. In other words, the bottom 143 is disposed between the heat sinks 120, 130 and the housing base 111. Therefore, the heat sinks 120, 130 are provided with the refrigerant 170 disposed between them and the housing 110.

[0075] <Effects> Here, the effects of the power conversion device 100 will be described in comparison with a power conversion device of a first comparative example (hereinafter simply referred to as the first comparative example) using Fig. 5. The first comparative example has the same components as the power conversion device 100. However, in the first comparative example, the heat sinks 120, 130 and the housing 110 are electrically insulated. Fig. 5 is an equivalent circuit diagram between the arm elements 11, 12 and the housing 110.

[0076] As shown in FIG. 5 , in the first comparative example, a parasitic capacitance (stray capacitance) is formed between the arm elements 11, 12 (electrodes 11e, 12e) and the heat sinks 120, 130, i.e., in the insulator 150. Furthermore, in the first comparative example, a potential difference is generated between the heat sinks 120, 130 and the housing 110. Therefore, in the first comparative example, a potential difference is applied to the refrigerant 170. Therefore, as shown by the dashed line in FIG. 5 , in the first comparative example, a parasitic capacitance (stray capacitance) is formed between the heat sinks 120, 130 and the housing 110, i.e., in the refrigerant 170. In this case, in the first comparative example, there is a risk that electrolysis of the refrigerant 170 will occur due to the potential difference.

[0077] If electrolysis occurs in the refrigerant 170, the following problems may occur: The heat sinks 120, 130 become more susceptible to electrolytic corrosion. Combustible gases are generated from the refrigerant 170. The cooling performance of the refrigerant 170 decreases. The amount of refrigerant 170 consumed increases. The refrigerant 170 turns into a jelly-like substance.

[0078] In contrast, in the power conversion device 100, the heat sinks 120, 130 are electrically connected to the housing 110 with the coolant 170 disposed therebetween. This makes it difficult for a potential difference to occur between the heat sinks 120, 130 and the housing 110. Furthermore, the power conversion device 100 can suppress the application of a potential difference to the coolant 170. As shown by the solid lines between the heat sinks 120, 130 and the housing 110 in Fig. 5, in the power conversion device 100, parasitic capacitance (stray capacitance) is unlikely to occur in the coolant 170.

[0079] Therefore, the power conversion device 100 can suppress electrolysis of the refrigerant 170. Since the power conversion device 100 suppresses electrolysis of the refrigerant 170, it can suppress the occurrence of the above-mentioned problems.

[0080] In this embodiment, the housing 110 is used as the second metal part. However, the second metal part is not limited to the housing 110. The second metal part may be a chassis of a mobile object, or the like. In this case, the second metal part is provided outside the power conversion device 100. In other words, the heat sinks 120 and 130 are provided with the coolant 170 disposed between them and the second metal part that is outside the power conversion device 100. The heat sinks 120 and 130 are electrically connected to the second metal part.

[0081] Furthermore, in this embodiment, the power conversion device 100 including semiconductor switching elements as electronic components has been described. However, the electronic components are not limited to semiconductor switching elements. A capacitor or the like can also be used as the electronic component. The capacitor has electrodes formed on both sides. In this case, the capacitor is attached to the heat sinks 120 and 130 instead of the arm elements 11 and 12. This configuration can be said to be an electronic device including an electronic component such as a capacitor, at least one heat sink 120 and 130 to which the electronic component is attached, and a resin frame 140 that forms a first flow path 145 together with the heat sink 120 and 130.

[0082] Second Embodiment A power conversion device 100 according to a second embodiment will be described with reference to Figs. 6 and 7. In this embodiment, differences from the first embodiment will be described. The main differences in this embodiment are that a potential difference occurs between the arm elements 11 and 12 and that the heat sinks 120 and 130 are electrically connected. Fig. 6 is a cross-sectional view corresponding to Fig. 3. Fig. 7 is an equivalent circuit diagram corresponding to Fig. 5.

[0083] 6, the upper arm element 11 is attached to the heat sink base 121 so that the electrode 11c faces the insulator 150. On the other hand, the lower arm element 12 is attached to the heat sink base 131 so that the electrode 12e faces the insulator 150. The electrodes 11c and 12e are electrodes at different potentials. For example, the electrode 11c is the collector electrode of the upper arm element 11. The electrode 12e is the emitter electrode of the lower arm element 12. As described above, the upper arm element 11 and the lower arm element 12 are semiconductor switching elements connected in series.

[0084] The first heat sink 120 has a connection portion 124 extending from the heat sink base 121 toward the second heat sink 130. On the other hand, the second heat sink 130 has a connection portion 134 extending from the heat sink base 131 toward the first heat sink 120. The connection portion 124 and the connection portion 134 are disposed opposite each other and are connected to each other. The first heat sink 120 is electrically connected to the second heat sink 130.

[0085] Furthermore, the second heat sink 130 is fixed to the housing 110. Therefore, the second heat sink 130 is electrically connected to the housing 110. On the other hand, the first heat sink 120 is not fixed to the housing 110. However, the first heat sink 120 is electrically connected to the housing 110 via the second heat sink 130. Note that the power conversion device 100 may include three or more heat sinks corresponding to the first metal portion.

[0086] The heat sink bases 121 and 131 correspond to opposing portions. The connection portions 124 and 134 correspond to first connection portions. The extension portion 132 corresponds to second connection portions.

[0087] The heat sinks 120 and 130 correspond to the first metal part. The housing 110 corresponds to the second metal part. However, a coolant 170 is disposed between the first heat sink 120 and the second heat sink 130. Furthermore, the first heat sink 120 and the second heat sink 130 are electrically connected. Therefore, in this embodiment, the first heat sink 120 can be regarded as the first metal part, and the second heat sink 130 and the housing 110 can be regarded as the second metal part. In other words, between the first heat sink 120 and the second heat sink 130, the first heat sink 120 corresponds to the first metal part, and the second heat sink 130 corresponds to the second metal part.

[0088] The heat sinks 120 and 130 have a first parasitic inductance, which is a parasitic inductance at the connection portions 124 and 134. The first parasitic inductance can also be said to be a parasitic inductance between the heat sink base portions 121 and 131 of the heat sinks 120 and 130.

[0089] The heat sinks 120 and 130 have a second parasitic inductance, which is a parasitic inductance in the extension portion 132. The second parasitic inductance can also be said to be a parasitic inductance between the heat sink base portion 131 and the housing 110 in the second heat sink 130.

[0090] The heat sinks 120 and 130 are configured such that the second parasitic inductance is greater than the first parasitic inductance at least at one location. For example, the extension portion 132 is provided longer than the connection portions 124 and 134. This allows the second parasitic inductance to be greater than the first parasitic inductance.

[0091] Here, the effects of the power conversion device 100 will be described in comparison with a power conversion device of a second comparative example (hereinafter referred to as the second comparative example) using Fig. 7. The second comparative example has the same components as the power conversion device 100 of the present embodiment. However, in the second comparative example, the heat sinks 120 and 130 are electrically insulated from the housing 110. Fig. 7 is an equivalent circuit diagram between the arm elements 11 and 12.

[0092] As shown in FIG. 7 , in the second comparative example, a parasitic capacitance (stray capacitance) is formed between the upper arm element 11 (electrode 11 e) and the first heat sink 120, i.e., in the insulator 150. Furthermore, in the second comparative example, a potential difference is generated between the heat sinks 120 and 130. Therefore, in the second comparative example, a potential difference is applied to the refrigerant 170. Therefore, as shown by the dashed line in FIG. 7 , in the second comparative example, a parasitic capacitance (stray capacitance) is formed between the heat sinks 120 and 130, i.e., in the refrigerant 170. In this case, in the second comparative example, there is a risk that the potential difference will cause electrolysis of the refrigerant 170.

[0093] In contrast, in the power conversion device 100, the first heat sink 120 and the second heat sink 130 are electrically connected with the coolant 170 disposed therebetween. Furthermore, in the power conversion device 100, the second heat sink 130 and the housing 110 are electrically connected with the coolant 170 disposed therebetween. Therefore, a potential difference is unlikely to occur between the heat sinks 120 and 130. Furthermore, the power conversion device 100 can suppress a potential difference from being applied to the coolant 170. As shown in FIG. 7 , the paths in which parasitic inductances 181 and 182 are formed, the power conversion device 100 is unlikely to generate parasitic capacitance in the coolant 170. Therefore, the power conversion device 100 of this embodiment can achieve the same effects as the above-described embodiments.

[0094] 7, a first parasitic inductance 181 is formed between the first heat sink 120 and the second heat sink 130, and a second parasitic inductance 182 is formed between the second heat sink 130 and the housing 110. The second parasitic inductance 182 is larger than the first parasitic inductance 181.

[0095] Therefore, the power conversion device 100 can confine the noise generated from the arm elements 11 and 12 within the power conversion device 100. In other words, the power conversion device 100 can confine the noise generated from the arm elements 11 and 12 within the loop indicated by the two-dot chain line. This allows the power conversion device 100 to suppress the noise generated from the arm elements 11 and 12 from being radiated outside the power conversion device 100.

[0096] (Modification 1) A modification of the second embodiment will be described with reference to Fig. 8 . As shown in Fig. 8 , the housing 110 may not include some of the mounting portions 113. The resin frame portion 140 may be attached to the mounting portions 112 together with the second heat sink 130. In other words, the fixing portion 146 and the extension portion 132 are fastened together. The power conversion device 100 of modification 1 can achieve the same effects as those of the second embodiment.

[0097] (Third Embodiment) A power conversion device 100 according to a third embodiment will be described using Figures 9 and 10. In this embodiment, differences from the second embodiment will be described. The main differences in this embodiment are that phase arm elements 21 and 22 are used instead of arm elements 11 and 12, the configuration of heat sinks 120 and 130, and the configuration of a resin frame 140a. In the power conversion device 100, a potential difference occurs between the phase arm elements 21 and 22. A smoothing capacitor 42 is mounted on the mounting portion 114.

[0098] 10 , U-phase upper arm element 21 has a collector electrode 21c exposed on one surface and an emitter electrode 21e exposed on the opposite surface. U-phase lower arm element 22 has a collector electrode 22c exposed on one surface and an emitter electrode 22e exposed on the opposite surface. Phase arm elements 21, 22 are arranged so that emitter electrode 21e and collector electrode 22c face each other. In other words, power conversion device 100 can be said to have phase arm elements 21, 21 arranged vertically.

[0099] 9 and 10, the cooler that cools the phase arm elements 21 and 22 includes a first heat sink 120, a second heat sink 130, and a resin frame 140a. The cooler is attached to a housing 110a. The housing 110a does not have an attachment portion 113.

[0100] The first heat sink 120 includes a first upper heat sink 120a and a first lower heat sink 120b, and the second heat sink 130 includes a second upper heat sink 130a and a second lower heat sink 130b.

[0101] The first upper heat sink 120a includes a heat sink base 121a, an extension 122a, heat dissipation fins 123a, and a connection 124a. The heat sink base 121a includes a portion facing the collector electrode 21c of the U-phase upper arm element 21. The collector electrode 21c is attached to the heat sink base 121a via an insulator 150.

[0102] The heat sink base 121a also includes a portion between the extension portion 122a and the portion facing the collector electrode 21c, and also includes a portion between the connection portion 124a and the portion facing the collector electrode 21c.

[0103] The extension portion 122a is a portion that extends from the heat sink base 121a. The extension portion 122a is provided so as to be bent relative to the heat sink base 121a. The heat dissipation fins 123a are provided so as to protrude from the heat sink base 121a.

[0104] The connecting portion 124a is a portion that extends from the heat sink base 121a to the opposite side to the extending portion 122a. The connecting portion 124a is connected to the connecting portion 134a of the second upper heat sink 130a. Thus, the first upper heat sink 120a is electrically connected to the second upper heat sink 130a.

[0105] The first lower heatsink 120b includes a heatsink base 121b, heat dissipation fins 123b, and a connecting portion 124b. The heatsink base 121b includes a portion facing the collector electrode 22c of the U-phase lower arm element 22. The collector electrode 22c is attached to the heatsink base 121b via an insulator 150. The heatsink base 121b also includes a portion between the portion facing the collector electrode 22c and the connecting portion 124b.

[0106] The heat dissipation fins 123b are provided so as to protrude from the heat sink base 121b. The connection portion 124b is a portion that extends from the heat sink base 121b. The connection portion 124b is connected to the connection portion 134b of the second lower heat sink 130b. Thus, the first lower heat sink 120b is electrically connected to the second lower heat sink 130b.

[0107] The second upper heatsink 130a includes a heatsink base 131a, heat dissipation fins 133a, and a connecting portion 134a. The second upper heatsink 130a has the same shape as the first lower heatsink 120b. The heatsink base 131a includes a portion that faces the emitter electrode 21e of the U-phase upper arm element 21. The emitter electrode 21e is attached to the heatsink base 131a via an insulator 150. The first upper heatsink 120a and the second upper heatsink 130a are provided as a pair and can be considered heatsinks for cooling the U-phase upper arm element 21.

[0108] The second lower heatsink 130b includes a heatsink base 131b, an extension 132b, heat dissipation fins 133b, and a connection 134b. The second lower heatsink 130b has the same shape as the first upper heatsink 120a. The heatsink base 131b includes a portion facing the emitter electrode 22e of the U-phase lower arm element 22. The emitter electrode 22e is attached to the heatsink base 131b via an insulator 150. The first lower heatsink 120b and the second lower heatsink 130b are provided as a pair and can be considered heatsinks for cooling the U-phase lower arm element 22.

[0109] The heat sinks 120 and 130 correspond to the first metal part. The housing 110a corresponds to the second metal part. However, a coolant 170 is disposed between the first lower heat sink 120b and the second upper heat sink 130a. Furthermore, the first lower heat sink 120b and the second upper heat sink 130a are electrically connected via the housing 110a, etc.

[0110] Therefore, in this embodiment, the first lower heat sink 120b can be considered as the first metal part, and the second upper heat sink 130a can be considered as the second metal part. Also, in this embodiment, the second upper heat sink 130a can be considered as the first metal part, and the first lower heat sink 120b can be considered as the second metal part. In other words, between the first lower heat sink 120b and the second upper heat sink 130a, one corresponds to the first metal part, and the other corresponds to the second metal part.

[0111] The heat sinks 120a, 130a have a first parasitic inductance, which is a parasitic inductance at the connecting portions 124a, 134a. The first parasitic inductance can also be considered as a parasitic inductance between the heat sink bases 121a, 131a of the heat sinks 120a, 130a. The first parasitic inductance may also include a parasitic inductance at a portion of the first upper heat sink 120a between the connecting portion 124a and the portion where the collector electrode 21c faces.

[0112] The heat sinks 120a, 130a have a second parasitic inductance, which is a parasitic inductance in the extension portion 122a. The second parasitic inductance can also be considered as a parasitic inductance between the heat sink base 121a and the housing 110a in the first upper heat sink 120a. The second parasitic inductance may also include a parasitic inductance in a portion of the first upper heat sink 120a between the portion facing the collector electrode 21c and the extension portion 122a. Similarly, the heat sinks 120b, 130b have a first parasitic inductance and a second parasitic inductance.

[0113] 9 and 10 , the resin frame 140a includes a frame base 141a, sidewalls 142a, and a fixing portion 146a. The frame base 141a is annular. The frame base 141a includes a portion facing the first upper heat sink 120a, a portion disposed between the second upper heat sink 130a and the first lower heat sink 120b, and a portion facing the second lower heat sink 130b.

[0114] The frame base 141a has a side wall 142a at a location facing the first upper heat sink 120a. The frame base 141a has a side wall 142a at a location facing the second lower heat sink 130b. Therefore, the inner circumferential surface of the frame base 141a forms an opening 144a.

[0115] The frame base 141a is attached to the first upper heat sink 120a to form a first flow path 145a between the frame base 141a and the first upper heat sink 120a. Similarly, the frame base 141a is attached to the second lower heat sink 130b to form a first flow path 145a between the frame base 141a and the first upper heat sink 120a.

[0116] Furthermore, the frame base 141a is attached to the second upper heat sink 130a and the first lower heat sink 120b, thereby forming a first flow path 145a between the second upper heat sink 130a and the first lower heat sink 120b. Thus, a portion of the first flow path 145a is provided between the second upper heat sink 130a and the first lower heat sink 120b.

[0117] Furthermore, as described above, if one of the first lower heat sink 120b and the second upper heat sink 130a is considered to be the first metal part and the other is considered to be the second metal part, then the second upper heat sink 130a, together with the first lower heat sink 120b and the resin frame part 140a, can be said to form the first flow path 145a.

[0118] The first flow paths 145a are connected to each other by refrigerant pipes 143a. That is, the refrigerant 170 flows through the refrigerant pipes 143a and into the first flow paths 145a.

[0119] The fixing portion 146a protrudes from the frame base 141a. The fixing portion 146a has a through hole and a collar 146c, similar to the fixing portion 146. The resin frame 140a, together with the frame base 141a, is fixed to the housing 110a with bolts 3.

[0120] The power conversion device 100 of the third embodiment can achieve the same effects as the second embodiment.

[0121] 11 , the second upper heat sink 130a and the first lower heat sink 120b are electrically connected by a first wire 191. One end of the first wire 191 is connected to a first wire connecting portion 190a provided on the second upper heat sink 130a. The other end of the first wire 191 is connected to a second wire connecting portion 190b provided on the first lower heat sink 120b.

[0122] The second lower heat sink 130b and the housing 110a are electrically connected by a second wire 192. One end of the second wire 192 is connected to a third wire connection portion 190c provided on the second lower heat sink 130b. The other end of the second wire 192 is connected to a fourth metal connection portion 190d that is electrically connected to the housing 110a.

[0123] The wire connection portions 190a to 190c are, for example, welded portions, etc. The fourth connection portion 190d is, for example, a metal washer, etc. However, the connection method of the wires 191 and 192 is not particularly limited as long as they are electrically connected to the target portions.

[0124] The first upper heat sink 120a does not have an extension portion 122a, and the second lower heat sink 130b does not have an extension portion 132b.

[0125] The power conversion device 100 of Modification 2 can achieve the same effects as the third embodiment. Furthermore, the power conversion device 100 of Modification 2 can make the heat sinks 120a, 120b, 130a, and 130b have the same shape. Therefore, the power conversion device 100 of Modification 2 can reduce the number of types of heat sinks compared to the third embodiment.

[0126] Although the present disclosure has been described with reference to the embodiments, it is understood that the present disclosure is not limited to the embodiments or structures. The present disclosure also encompasses various modifications and modifications within the scope of equivalents. In addition, although various combinations and forms are shown in the present disclosure, other combinations and forms including only one element, more, or less than one element are also within the scope and spirit of the present disclosure.

[0127] (Disclosure of Technical Ideas) This specification discloses multiple technical ideas described in the following multiple clauses. Some clauses may be described in a multiple dependent form, with the subsequent clause alternatively referring to the preceding clause. Furthermore, some clauses may be described in a multiple dependent form, with the subsequent clause referring to another multiple dependent clause. These multiple dependent clauses define multiple technical ideas.

[0128] (Technical Idea 1) A power conversion device comprising: at least one electronic component (11, 12; 21, 22); at least one first metal part (120, 130; 130a) to which the electronic component is attached; and a resin frame part (140; 140a) that, together with the first metal part, forms a refrigerant flow path (145) through which a refrigerant (170) flows, wherein the first metal part is provided with the refrigerant disposed between the first metal part and a second metal part (110; 120b), and the first metal part and the second metal part are electrically connected.

[0129] (Technical Concept 2) The power conversion device according to Technical Concept 1, wherein the second metal portion is connected to a ground potential.

[0130] (Technical Idea 3) A power conversion device according to Technical Idea 1 or 2, comprising a plurality of the first metal parts, wherein the plurality of first metal parts are electrically connected to each other, and the plurality of first metal parts are electrically connected to the second metal parts, and the first metal parts have opposing portions of the electronic component, a first connection portion extending from the opposing portion and connected to another of the first metal parts, and a second connection portion extending from the opposing portion and connected to the second metal part, and at least one location of the plurality of first metal parts, a parasitic inductance (182) at the second connection portion is greater than a parasitic inductance (181) at the first connection portion.

[0131] (Technical Concept 4) The power conversion device according to any one of Technical Concepts 1 to 3, further comprising a semiconductor switching element as the electronic component.

[0132] (Technical Concept 5) The power conversion device according to Technical Concept 4, wherein two of the semiconductor switching elements are connected in series.

[0133] (Technical Concept 6) The power conversion device according to any one of Technical Concepts 1 to 5, wherein the electronic component is attached to the first metal part via an insulating material (150).

[0134] (Technical Idea 7) A power conversion device according to any one of Technical Ideas 1 to 6, which includes the second metal part, wherein the second metal part is a cooler that cools other electronic components (41, 42) different from the electronic component, and has another refrigerant flow path (116) that communicates with the refrigerant flow path and through which the refrigerant flows.

[0135] (Technical Idea 8) A power conversion device according to any one of Technical Ideas 1 to 6, comprising the second metal part, wherein the second metal part forms the refrigerant flow path together with the first metal part and the resin frame part.

[0136] (Technical Concept 9) The power conversion device according to any one of Technical Concepts 1 to 8, wherein the first metal part is electrically connected to the second metal part via a wire.

[0137] (Technical Idea 10) An electronic device comprising at least one electronic component (11, 12), at least one first metal part (120, 130) to which the electronic component is attached, and a resin frame part (140) that, together with the first metal part, forms a refrigerant flow path (145) through which a refrigerant (170) flows, wherein the first metal part is provided with the refrigerant disposed between the first metal part and a second metal part (110), and the first metal part and the second metal part are electrically connected.

Claims

1. A power conversion device comprising: at least one electronic component (11, 12; 21, 22); at least one first metal part (120, 130; 130a) to which the electronic component is attached; and a resin frame part (140; 140a) that, together with the first metal part, forms a refrigerant flow path (145) through which a refrigerant (170) flows, wherein the first metal part is provided with a second metal part (110; 120b) and the refrigerant is disposed between the first metal part and the second metal part, and the first metal part and the second metal part are electrically connected.

2. The power conversion device according to claim 1, wherein the second metal portion is connected to a ground potential.

3. A power conversion device as described in claim 1 or 2, comprising a plurality of the first metal parts, the plurality of first metal parts being electrically connected to one another, and the plurality of first metal parts being electrically connected to the second metal part, the first metal parts having opposing portions of the electronic component, a first connection portion extending from the opposing portion and connected to another of the first metal parts, and a second connection portion extending from the opposing portion and connected to the second metal part, and the plurality of first metal parts, at at least one location, have a parasitic inductance (182) at the second connection portion greater than a parasitic inductance (181) at the first connection portion.

4. The power conversion device according to claim 1 or 2, wherein the electronic component comprises a semiconductor switching element.

5. The power conversion device according to claim 4, wherein two of said semiconductor switching elements are connected in series.

6. The power conversion device according to claim 1 or 2, wherein the electronic component is attached to the first metal part via an insulating material (150).

7. A power conversion device as described in claim 1 or 2, which is provided with the second metal part, the second metal part being a cooler that cools other electronic components (41, 42) different from the electronic component, and having another refrigerant flow path (116) that communicates with the refrigerant flow path and through which the refrigerant flows.

8. A power conversion device according to claim 1 or 2, comprising the second metal part, wherein the second metal part forms the refrigerant flow path together with the first metal part and the resin frame part.

9. The power conversion device according to claim 1 or 2, wherein the first metal part is electrically connected to the second metal part via a wire.

10. An electronic device comprising at least one electronic component (11, 12), at least one first metal part (120, 130) to which the electronic component is attached, and a resin frame part (140) which, together with the first metal part, forms a refrigerant flow path (145) through which a refrigerant (170) flows, wherein the first metal part is provided with the refrigerant disposed between the first metal part and a second metal part (110), and the first metal part and the second metal part are electrically connected.

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