Power conversion device

Abstract

To provide a power conversion device, in a configuration simpler than ever, capable of suppressing increase in load applied to a cooling unit while insulating heat propagated from a power module to a control substrate.SOLUTION: A power conversion device comprises: a casing; a capacitor housed in the casing; a power module housed in the casing, and converting a DC voltage from the capacitor into an AC voltage; a cooling unit that cools down the power module; a control substrate housed in the casing with a gap interposed between the control substrate and the power module, controlling the drive of the power module; and a heat insulation part housed in the casing so as to be arranged between the power module and the control substrate. The heat insulation part is brought into contact with an inner surface of the casing to partition an interior of the casing into: a space where the power module is arranged; and a space where the control substrate is arranged.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to a power conversion device. [Background technology]

[0002] For example, Patent Document 1 discloses a semiconductor device (power conversion device) in which a power module is covered with a heat shielding member. In this semiconductor device, a control board mounting a circuit for controlling the power module is disposed above the heat shielding member.

[0003] The heat shielding member has a flat portion covering the top surface of the power module and a pair of support legs that hang down from both ends of the flat portion to cover the side surfaces of the power module, and the lower ends of the pair of support legs are fixed in contact with the surface of the base plate, thereby preventing heat from being transferred from the power module to the control board, and when heat is transferred to the heat shielding member, it is dissipated to the outside from the lower ends of the support legs via the base plate. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2005-333074 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the semiconductor device described in the above Patent Document 1, the heat shielding member needs to be disposed so as to avoid interference with the power module inside the case, and there is a demand for a heat shielding member with a simpler structure.

[0006] In recent years, in the field of power conversion devices that have power modules, there has been a growing trend to increase the voltage, current, frequency, and switching speed of power semiconductor elements in order to improve added value. As a result, power modules can become hotter.

[0007] In the semiconductor device described in the above Patent Document 1, the power module may be cooled by a cooler via a base plate. In this case, the heat shield plate is also cooled by the cooler via the base plate, and as a result of the temperature rise of the entire power module, the load on the cooler may increase.

[0008] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a power conversion device that can block heat transferred from a power module to a control board with a simpler configuration while suppressing an increase in the load on the cooler. [Means for solving the problem]

[0009] In order to solve the above problems, the power conversion device of the present disclosure comprises a casing, a capacitor housed in the casing, a power module housed in the casing and converting DC voltage from the capacitor into AC voltage, a cooler for cooling the power module, a control board housed in the casing with a gap between it and the power module and controlling the drive of the power module, and a heat shield housed in the casing and positioned between the power module and the control board, and the heat shield abuts against the inner surface of the casing to divide the interior of the casing into a space in which the power module is arranged and a space in which the control board is arranged. Effect of the Invention

[0010] According to the present disclosure, it is possible to provide a power conversion device that can block heat transferred from a power module to a control board with a simpler configuration while suppressing an increase in the load on a cooler. [Brief description of the drawings]

[0011] [Figure 1] 1 is a perspective view showing a schematic configuration of a power conversion device according to an embodiment of the present disclosure. [Diagram 2]2 is a plan view of the power module according to the first embodiment of the present disclosure taken along line II-II in FIG. 1. [Diagram 3] 3 is a cross-sectional view taken along line III-III in FIG. 2. [Figure 4] 4 is a diagram showing a direction in which heat is conducted through the heat shield according to the first embodiment of the present disclosure. FIG. [Diagram 5] FIG. 4 is a cross-sectional view of a power conversion device according to a second embodiment of the present disclosure, and corresponds to the portion shown in FIG. [Figure 6] 4 is a cross-sectional view of a power conversion device according to another embodiment of the present disclosure, the cross-sectional view corresponding to the portion shown in FIG. 3. FIG. [Figure 7] 4 is a cross-sectional view of a power conversion device according to another embodiment of the present disclosure, the cross-sectional view corresponding to the portion shown in FIG. 3. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, embodiments for implementing a power conversion device according to the present disclosure will be described with reference to the accompanying drawings.

[0013] First Embodiment [Power conversion device] The power conversion device is a device that converts DC power into three-phase AC power, etc. Examples of the power conversion device of the present embodiment include inverters used in systems such as power plants, and inverters used to drive electric motors in electric vehicles, etc.

[0014] As shown in Fig. 1, the power conversion device 100 includes a casing 1, an external input conductor 2, a capacitor 3, a power conversion unit 4, a cooler 5, a control board 6, and a heat shield 7. In Fig. 1, due to space limitations, the casing 1, the cooler 5, the control board 6, and the heat shield 7 are indicated by two-dot chain lines.

[0015] (Casing) The casing 1 forms an outer shell of the power conversion device 100. In this embodiment, the casing 1 is made of a metal such as aluminum or a synthetic resin, and has a rectangular parallelepiped shape. The casing 1 has two side surfaces arranged back-to-back.

[0016] For ease of explanation, the side facing one of the two sides will be referred to as the “input side 1a” and the side facing the other side will be referred to as the “output side 1b.” An external input conductor 2 for inputting DC power is drawn out from the input side 1a.

[0017] (external input conductor) The external input conductors 2 are a pair of electric conductors (bus bars) that supply DC power supplied from an external power system or the like to the power conversion device 100 to the capacitor 3. In this embodiment, the external input conductor 2 is formed of a metal including copper or the like. One end of the external input conductor 2 is connected to the capacitor 3, and the other end of the external input conductor 2 extends in a direction intersecting with the input side surface 1a of the casing 1.

[0018] (Capacitor) The capacitor 3 is a smoothing capacitor that stores the charge input from the external input conductor 2 and suppresses voltage fluctuations associated with power conversion. The capacitor 3 is housed in the casing 1. The DC voltage input from the external input conductor 2 is supplied to the power conversion unit 4 via the capacitor 3. The capacitor 3 has a main body 3a and a connection conductor 3b.

[0019] The main body 3a is a portion that mainly performs the function of the smoothing capacitor described above. The connection conductor 3b is an electric conductor (bus bar) for transmitting power from the main body 3a to the power conversion unit 4. The connection conductor 3b is made of a metal such as copper. The connection conductor 3b has a positive terminal 3p and a negative terminal 3n.

[0020] The positive electrode terminal 3p forms the positive electrode of the capacitor 3, and is a current path connecting the main body 3a and the positive electrode of the power module 40. The negative electrode terminal 3n forms the negative electrode of the capacitor 3, and is a current path connecting the main body 3a and the negative electrode of the power module 40.

[0021] The positive terminal 3p and the negative terminal 3n are arranged side by side with a gap therebetween. One end of each of the positive terminal 3p and the negative terminal 3n is connected to the main body 3a. Detailed illustration of the connection state between the positive terminal 3p and the negative terminal 3n and the main body 3a is omitted. The other end of each of the positive terminal 3p and the negative terminal 3n is connected to the power module 40.

[0022] (Power conversion section) The power conversion unit 4 converts the voltage input from the capacitor 3. The power conversion unit 4 is housed in a casing 1. In this embodiment, the power conversion unit 4 has three power modules 40 each responsible for outputting a U phase, a V phase, and a W phase, in order to output three-phase AC power. Therefore, the power conversion device 100 in this embodiment is a three-phase inverter including three power modules 40.

[0023] (Power Module) The power module 40 is a device that converts input power and outputs it. As shown in Figures 2 and 3, the power module 40 includes a base plate 41, a circuit board 42, an external output conductor 43, a case 44, an insulating part 45, and a bonding wire Wb.

[0024] The base plate 41 is a member having a flat plate shape. The base plate 41 has a front surface 41a and a back surface 41b located on the back side of the front surface 41a. That is, the front surface 41a and the back surface 41b of the base plate 41 are back-to-back in a state of being parallel to each other. The back surface 41b of the base plate 41 is fixed to the cooler 5 via a bonding material or the like (not shown). For example, copper is used for the base plate 41 in this embodiment. Note that a metal such as aluminum may be used for the base plate 41.

[0025] The circuit board 42 has an insulating plate 421 , a front surface pattern 422 , a power semiconductor element 423 , and a back surface pattern 424 .

[0026] The insulating plate 421 has a flat plate shape. The insulating plate 421 has a first surface 421a and a second surface 421b located on the back side of the first surface 421a. That is, the first surface 421a and the second surface 421b of the insulating plate 421 are back-to-back in a state of being parallel to each other. A back surface pattern 424, which is a pattern of copper foil or the like, is formed on one side of the second surface 421b of the insulating plate 421. The back surface pattern 424 is fixed to the center of the front surface 41a of the base plate 41 via a bonding material S.

[0027] The insulating plate 421 in this embodiment is made of an insulating material such as ceramic. Note that, as the insulating material for forming the insulating plate 421, paper phenol, paper epoxy, glass composite, glass epoxy, glass polyimide, fluororesin, etc. can be used in addition to ceramic.

[0028] Surface pattern 422 is a pattern of copper foil or the like that spreads in a plane on first surface 421a of insulating plate 421. Surface pattern 422 is formed, for example, by being fixed to first surface 421a of insulating plate 421 by bonding or the like, and then being subjected to etching or the like.

[0029] A plurality of surface patterns 422 are arranged on the first surface 421a of the insulating plate 421. The plurality of surface patterns 422 are arranged adjacent to one another with gaps interposed therebetween in the direction in which the insulating plate 421 extends. In this embodiment, a case in which three surface patterns 422 are arranged on the first surface 421a of the insulating plate 421 will be described as an example. For convenience of description, the three surface patterns 422 will be referred to as a first surface pattern 422a, a second surface pattern 422b, and a third surface pattern 422c below.

[0030] The first surface pattern 422a and the second surface pattern 422b are patterns for inputting and outputting DC current to and from the capacitor 3, and correspond to an inlet portion or an outlet portion of a loop between PN formed in the surface pattern 422. In this embodiment, the other end of the positive electrode side terminal 3p of the capacitor 3 is connected to the first surface pattern 422a, and the other end of the negative electrode side terminal 3n of the capacitor 3 is connected to the second surface pattern 422b. An external output conductor 43 for outputting AC current converted by the power semiconductor element 423 to a load (not shown) provided outside the power conversion device 100 is connected to the third surface pattern 422c.

[0031] The power semiconductor elements 423 are circuit elements that convert power by switching operations that turn on and off voltage and current. The power semiconductor elements 423 are, for example, switching elements such as IGBTs and MOSFETs. In this embodiment, as an example, a case where a MOSFET is applied to the power semiconductor is shown. These four power semiconductor elements 423 are connected to a surface pattern 422 of the circuit board 42. When an IGBT is used for the power semiconductor elements 423, a diode that passes a current in the opposite direction to the IGBT must be arranged in parallel.

[0032] The four power semiconductor elements 423 in this embodiment are composed of two first power semiconductor elements 423a and two second power semiconductor elements 423b. The first power semiconductor elements 423a are connected to the first surface pattern 422a. The second power semiconductor elements 423b are connected to the third surface pattern 422c.

[0033] When the power semiconductor element 423 is a MOSFET, the power semiconductor element 423 has an input surface on which an input terminal (not shown) corresponding to a drain is formed, an output surface on which an output terminal (not shown) corresponding to a source is formed, and a gate (not shown) corresponding to a terminal for inputting a control signal for controlling the switching of the power semiconductor element 423.

[0034] An input surface of the power semiconductor element 423 is electrically connected to the surface pattern 422 via a bonding material S. One end of a bonding wire Wb serving as a conductor is electrically connected to an output surface of the power semiconductor element 423. The bonding wire Wb is made of a metal such as aluminum. That is, the surface patterns 422 formed on the first surface 421a are electrically connected to each other by wire bonding.

[0035] An input surface of the first power semiconductor element 423a is connected to the first surface pattern 422a. One end of a bonding wire Wb is connected to the output surface of the first power semiconductor element 423a, and the other end is connected to the third surface pattern 422c. An input surface of the second power semiconductor element 423b is connected to the third surface pattern 422c. One end of a bonding wire Wb is connected to the output surface of the second power semiconductor element 423b, and the other end is connected to the second surface pattern 422b.

[0036] DC power is input to the first power semiconductor element 423a via the first surface pattern 422a, and DC power is input to the second power semiconductor element 423b via the second surface pattern 422b and a bonding wire Wb connecting the second surface pattern 422b and the second power semiconductor element 423b. The first power semiconductor element 423a and the second power semiconductor element 423b perform switching operations, whereby the DC power is converted into AC power and output to the third surface pattern 422c.

[0037] A control signal generated by a gate drive circuit board (not shown) provided outside the circuit board 42 is input to the power semiconductor element 423. The power semiconductor element 423 performs switching in accordance with this control signal. When the power semiconductor element 423 is an IGBT, the power semiconductor element 423 has an input surface corresponding to a collector, an output surface corresponding to an emitter, and a gate corresponding to a control signal input terminal.

[0038] The bonding material S used for joining the surface 41a of the base plate 41 to the back surface pattern 424 formed on the second surface 421b of the insulating plate 421, for joining the power semiconductor element 423 to the front surface pattern 422, and for joining the back surface 41b of the base plate 41 to the cooler 5 may be, for example, solder or a sintered material (powder of metal, etc.).

[0039] The external output conductor 43 is an electric conductor (bus bar) for outputting AC power converted by the power semiconductor element 423 to the outside of the power conversion device 100. The external output conductor 43 is formed of a metal including copper or the like. One end of the external output conductor 43 is connected to the third surface pattern 422c of the circuit board 42. As shown in FIG. 1, the other end of the external output conductor 43 extends outward beyond the output side surface 1b of the casing 1. To the other end of the external output conductor 43, for example, a wiring (not shown) for current output connected to a load such as a motor is connected.

[0040] The case 44 is a member that mechanically reinforces the external output conductor 43 and the connection conductor 3b of the capacitor 3 while being fixed to the surface 41a of the base plate 41. The case 44 is formed, for example, from a synthetic resin material (insulating material) or the like. For example, PPS (polyphenylene sulfide) can be used as the material for forming the case 44 in this embodiment. Note that a synthetic resin material other than PPS may also be used for the case 44. The case 44 is fixed to the surface 41a of the base plate 41 by, for example, an adhesive or the like.

[0041] The case 44 surrounds the circuit board 42 from the outside while covering the positive terminal 3p and the negative terminal 3n of the connecting conductor 3b and the external output conductor 43 from the outside. As shown in Fig. 2 and Fig. 3, the case 44 surrounds the circuit board 42 from the periphery in a direction along the surface 41a of the base plate 41. Therefore, the case 44, together with the base plate 41, defines a space in which the circuit board 42 is housed. In this embodiment, for convenience of explanation, this space in which the circuit board 42 is housed is referred to as a "potting space Rp."

[0042] The insulating section 45 is an insulating member disposed in the potting space Rp. A liquid potting material is filled into the potting space Rp from the outside (potting), and the components exposed in the potting space Rp are sealed. The potting material filled in the potting space Rp hardens over a predetermined period of time, and electrically insulates the components in the potting space Rp from one another and from the space outside the power module 40.

[0043] In this embodiment, the potting material may be, for example, silicon gel or epoxy resin. Note that, synthetic resins other than silicon gel and epoxy resin may be used as the potting material. Therefore, the insulating portion 45 is formed of this potting material. The insulating portion 45 in the potting space Rp is disposed so as to cover the surfaces of the circuit board 42, the bonding wires Wb, the external output conductor 43, and the connecting conductor 3b of the capacitor 3.

[0044] (cooler) As shown in Fig. 1, the cooler 5 is a device that mainly cools the power module 40 of the power conversion unit 4. The cooler 5 is provided so as to be stacked on the casing 1, and is fixed and integrated with the casing 1. The cooler 5 has a base 51 and heat dissipation fins 52. Note that in Fig. 3, the base 51 and the heat dissipation fins 52 are indicated by dotted lines.

[0045] The base 51 has a plate shape and includes a bonding surface 51a that is bonded to the rear surface 41b of the base plate 41 of the power module 40 via a bonding material S, and a heat dissipation surface 51b that faces the opposite side to the bonding surface 51a.

[0046] The joining surface 51a and the heat dissipation surface 51b are arranged back-to-back in parallel with each other. The heat dissipation fins 52 are columnar members arranged on the heat dissipation surface 51b of the base 51. Each heat dissipation fin 52 protrudes from the heat dissipation surface 51b to the side opposite the power module 40, with the base 51 at the center.

[0047] A liquid refrigerant W such as water is introduced into the cooler 5 from the outside. The heat dissipation surface 51b of the base 51 and the heat dissipation fins 52 are cooled by contact with the liquid refrigerant W introduced from the outside. The liquid refrigerant W is heated by heat exchange with the heat conducted from the power module 40 to the base 51 and the heat dissipation fins 52, and at the same time, cools the power module 40.

[0048] (Control board) The control board 6 is a board that controls the driving of the power semiconductor elements 423 and the like in the power module 40. The control board 6 is housed in the casing 1 with a gap between the control board 6 and the power module 40. As shown in Figs. 2 and 3, the control board 6 is supported from the power module 40 side by, for example, a bolt B or the like fixed to a base plate 41 in the power module 40. In this embodiment, the bolt B is fastened to the base plate 41 and the control board 6, so that the control board 6 is positioned in the casing 1 with a gap between the control board 6 and the power module 40. The control board 6 and the power semiconductor elements 423 are electrically connected by a signal line or the like (not shown).

[0049] (Heat shielding section) The heat shield 7 prevents heat from being transferred from the power module 40 to the control board 6. The heat shield 7 is housed in the casing 1. The heat shield 7 is disposed between the power module 40 and the control board 6. In this embodiment, the heat shield 7 is a plate-shaped heat shield 70. The heat shield 70 has an outer edge 70a as a surface corresponding to the thickness of the heat shield 70. The outer edge 70a abuts against the inner surface 10 of the casing 1 and the main body 3a of the condenser 3.

[0050] The heat shield 70 in this embodiment abuts against the side surface 13 of the inner surface 10 of the casing 1, thereby dividing the inside of the casing 1 into a first space R1 in which the power module 40 is disposed, and a second space R2 in which the control board 6 is disposed. Although detailed illustration is omitted, the heat shield 70 is formed with a hole through which the bolt B that connects the base plate 41 in the power module 40 and the control board 6 is inserted, for example, and the heat shield 70 is supported from the power module 40 side within the casing 1 by inserting the bolt B into this hole.

[0051] The heat shield 70 is formed of a thermally conductive material having a higher thermal conductivity in an in-plane direction of the heat shield 70 than in a thickness direction of the heat shield 70. The heat shield 70 in this embodiment is formed of graphene. Specifically, the heat shield 70 is formed to have an outer edge portion 70a by stacking a large number of sheet-shaped graphenes, for example.

[0052] Here, the direction in which heat moves in the heat shield 70 when heat is transferred from the power module 40 to the heat shield 70 in this embodiment will be described with reference to Fig. 4. In Fig. 4, the manner in which heat moves is indicated by solid arrows. The heat in the heat shield 70 moves in the in-plane direction of the heat shield 70, and also moves to the casing 1 through the outer edge 70a abutting against the side surface 13 of the inner surface 10 of the casing 1.

[0053] Moreover, the heat in the heat shield 70 moves in the in-plane direction of the heat shield 70, and also moves to the main body 3a of the condenser 3 through the outer edge portion 70a that abuts against the main body 3a. That is, the heat transferred to the heat shield 70 from the first space R1 side where the power module 40 is arranged is prevented from moving to the second space R2 side by the heat shield 70. Moreover, this heat does not remain in the heat shield 70, but is conducted to the casing 1 and the main body 3a of the condenser 3.

[0054] (Action and effect) A connection conductor 3b for inputting a current from the main body 3a of the capacitor 3 and an external output conductor 43 for outputting the converted current to the outside of the power conversion device 100 are connected to the circuit board 42 in the power module 40. Therefore, for example, when a heat shield 7 connected to a cooler 5 is disposed inside the casing 1 to divide the inside of the casing 1 into a first space R1 and a second space R2, the heat shield 7 may have a complex shape so as not to interfere with the connection conductor 3b and the external output conductor 43.

[0055] According to the above configuration, the heat shield 7 that suppresses the transfer of heat from the power module 40 to the control board 6 is realized with a simple configuration such as the heat shield plate 70. In addition, the transfer of heat from the first space R1 to the second space R2 in the casing 1, which is partitioned by the outer edge portion 70a of the heat shield plate 70 being in contact with the inner surface 10 of the casing 1 and the main body portion 3a of the condenser 3, is suppressed, and the heat transferred to the heat shield plate 70 moves to the casing 1 and the main body portion 3a of the condenser 3. As a result, the heat transferred to the heat shield plate 70 is not allowed to remain in the heat shield plate 70, but can be released to components other than the cooler 5, such as the casing 1 and the main body portion 3a of the condenser 3. Therefore, for example, the load on the cooler 5 can be reduced compared to a configuration in which the cooler 5 directly cools the heat shield portion 7. As a result, it is possible to suppress an increase in the load on the cooler 5 while blocking the heat transferred from the power module 40 to the control board 6 with a simpler configuration.

[0056] Furthermore, according to the above configuration, the heat shield 70 is formed from a thermally conductive material having a higher thermal conductivity in the in-plane direction than in the thickness direction, thereby better preventing heat from moving from the first space R1 to the second space R2 while better preventing heat from remaining in the heat shield 70.

[0057] Second Embodiment Next, a second embodiment of the power conversion device 100 according to the present disclosure will be described with reference to Fig. 5. In the second embodiment described below, components common to the first embodiment will be denoted by the same reference numerals in the drawings and will not be described. In the second embodiment, the configuration of the heat shield 7 in the power module 40 is different from the configuration described in the first embodiment.

[0058] (Heat shielding section) The heat shield 7 prevents heat from being transferred from the power module 40 to the control board 6. The heat shield 7 in this embodiment has a flat plate portion 71 and a plurality of side wall plate portions 72.

[0059] The flat plate portion 71 is plate-shaped. The flat plate portion 71 is disposed in the gap between the power module 40 and the control board 6. The flat plate portion 71 has an outer edge portion 71a as a surface corresponding to the thickness of the flat plate portion 71. The side wall plate portion 72 is plate-shaped. The side wall plate portion 72 in this embodiment is fixed to the top surface 11 on the inner surface 10 of the casing 1 in a state where the side wall plate portion 72 is connected to each of the four outer edge portions 71a of the flat plate portion 71 so as to be integral with the flat plate portion 71. The outer edge portions 72a of the side wall plate portion 72 abut against the top surface 11. Therefore, the four side wall plate portions 72 are housed in the casing 1 integrally with the flat plate portion 71, and connect the flat plate portion 71 to the top surface 11. The top surface 11 and the side surface 13 described in the first embodiment are in a perpendicular relationship.

[0060] Adjacent side wall plate portions 72 of the four side wall plate portions 72 are connected together. Therefore, the space inside the casing 1 is divided by the flat plate portion 71 and the four side wall plate portions 72 into a first space R1 in which the power module 40 is disposed and a second space R2 in which the control board 6 is disposed. In this embodiment, the volume of the first space R1 is larger than the volume of the second space R2.

[0061] The four side wall plate portions 72 surround the control board 6 from the direction in which the flat plate portion 71 extends. That is, the four side wall plate portions 72 surround the control board 6 from the in-plane direction of the flat plate portion 71. Due to space limitations, only cross sections of two of the four side wall plate portions 72 that face each other with the control board 6 sandwiched therebetween are shown in Fig. 5.

[0062] Although detailed illustration is omitted, the flat plate portion 71 has a hole through which the bolt B connecting the base plate 41 and the control board 6 in the power module 40 is inserted, and the bolt B is inserted into this hole, whereby the flat plate portion 71 is supported from the power module 40 side within the casing 1.

[0063] The flat plate portion 71 is formed of a thermally conductive material having a higher thermal conductivity in an in-plane direction of the flat plate portion 71 than in a thickness direction of the flat plate portion 71. The side wall plate portion 72 is formed of a thermally conductive material having a higher thermal conductivity in an in-plane direction of the side wall plate portion 72 than in a thickness direction of the side wall plate portion 72. The flat plate portion 71 and the side wall plate portion 72 in this embodiment are formed of graphene.

[0064] Here, the direction of heat transfer in the heat shield 7 when heat is transferred from the power module 40 to the heat shield 7 in this embodiment will be described with reference to FIG. 6. In FIG. 6, the manner in which heat transfer occurs is indicated by solid arrows. The heat in the heat shield 7 transfers in the in-plane direction of each of the flat plate portion 71 and the side wall plate portion 72 of the heat shield 7, and also transfers to the casing 1 through the outer edge portion 72a of the side wall plate portion 72 abutting against the top surface 11. That is, the heat transferred to the heat shield 7 from the first space R1 side where the power module 40 is arranged is prevented from transferring to the second space R2 side by the flat plate portion 71 and the side wall plate portion 72. In addition, the heat does not remain in the flat plate portion 71 and the side wall plate portion 72, but is transferred from the side wall plate portion 72 to the casing 1.

[0065] (Action and effect) In the above configuration, the heat shield 7 is formed by the flat plate portion 71 and the four side wall plate portions 72 surrounding the control board 6 from the in-plane direction of the flat plate portion 71 (the direction in which the flat plate portion 71 extends). The outer edge portions 72a of the side wall plate portions 72 are connected to the top surface 11 of the inner surface 10 of the casing 1. This makes it possible to further suppress the transfer of heat from the first space R1 to the second space R2 due to convection.

[0066] Furthermore, according to the above configuration, the flat plate portion 71 and the side wall plate portion 72 of the heat shield 7 are made of a heat conductive material having a higher thermal conductivity in the in-plane direction than in the plate thickness direction. Therefore, it is possible to further suppress the transfer of heat from the first space R1 to the second space R2, while further suppressing the heat from remaining in the heat shield 7.

[0067] (Other embodiments) Although the embodiments of the present disclosure have been described in detail above with reference to the drawings, the specific configurations are not limited to those of the embodiments, and additions, omissions, substitutions, and other modifications of the configurations are possible without departing from the gist of the present disclosure.

[0068] The heat shield plate 70 described in the first embodiment is not limited to being made of graphene, and may be made of a material such as borophene. Therefore, the heat shield plate 70 may be made of a thermally conductive material having a higher thermal conductivity in the in-plane direction than in the thickness direction. The flat plate portion 71 and the side wall plate portion 72 in the heat shield portion 7 described in the second embodiment are not limited to being made of graphene, and may be made of a material such as borophene. Therefore, the heat shield plate 70, the flat plate portion 71, and the side wall plate portion 72 described in the embodiment may be made of a thermally conductive material having a higher thermal conductivity in the in-plane direction than in the thickness direction.

[0069] Moreover, the side wall plate portion 72 described in the second embodiment may be configured to abut against the side surface 13 of the inner surface 10 of the casing 1.

[0070] The above-described power conversion device 100 may further include a gate drive board (not shown) that is disposed between the heat shield 7 and the power module 40 and is capable of controlling the switching of the power semiconductor element 423. The gate drive board is electrically connected to the gate of the power semiconductor element 423 and the control board 6 by, for example, a signal line or the like. The gate drive board may also have a hole formed therein through which the above-described bolt B is inserted, and the gate drive board may be supported from the power module 40 side within the casing 1 by inserting the bolt B into this hole. Therefore, the heat shield 7 may have any configuration as long as it thermally protects the above-mentioned control circuit from the power module 40 within the casing 1.

[0071] 7, the power conversion device 100 may further include a current sensor 8 housed in the casing 1 and capable of detecting a current value flowing through the external output conductor 43. The current sensor 8 is a through-type current sensor (current transformer) capable of measuring a current value without contacting the external output conductor 43. The current sensor 8 is disposed so as to surround a part of the outer surface of the external output conductor 43 in a state in which the current sensor 8 is in contact with the joint surface 51a of the base 51 of the cooler 5. When the power conversion device 100 includes the current sensor 8, the outer edge portion 70a of the heat shield 70 described in the first embodiment may be in contact with the current sensor 8, for example.

[0072] In the above embodiment, an inverter has been described as an example of the power conversion device 100, but the power conversion device 100 is not limited to the inverter. The power conversion device 100 may be, for example, a converter or a combination of an inverter and a converter, which performs power conversion using a power semiconductor element 423. When the power conversion device 100 is a converter, an AC voltage is input from an external input power source (not shown) to the external output conductor 43, and the power semiconductor element 423 in the circuit board 42 converts this AC voltage into a DC voltage, and the DC voltage from the power semiconductor element 423 is output to the outside of the power conversion device 100 through the connecting conductor 3b.

[0073] <Additional Notes> The power conversion device described in each embodiment can be understood, for example, as follows.

[0074] (1) A power conversion device 100 according to a first aspect includes a casing 1, a capacitor 3 housed in the casing 1, a power module 40 housed in the casing 1 and converting a DC voltage from the capacitor 3 into an AC voltage, a cooler 5 for cooling the power module 40, a control board 6 housed in the casing 1 with a gap between it and the power module 40 and controlling the drive of the power module 40, and a heat shield 7 housed in the casing 1 and disposed between the power module 40 and the control board 6, and the heat shield 7 abuts against an inner surface 10 of the casing 1, thereby dividing the interior of the casing 1 into a space in which the power module 40 is disposed and a space in which the control board 6 is disposed.

[0075] This makes it possible to suppress the transfer of heat between the spaces within the casing 1 that are partitioned by the heat shield 7, with a simple configuration in which the heat shield 7 abuts against the inner surface 10 of the casing 1. In addition, since the heat transferred to the heat shield 7 moves to the casing 1, this heat can be released to the casing 1 without remaining in the heat shield plate 70.

[0076] (2) A power conversion device 100 according to a second aspect is the power conversion device 100 of (1), wherein the heat shield 7 has a heat shield plate 70 arranged in the gap between the power module 40 and the control board 6, and an outer edge portion 70a of the heat shield plate 70 may abut against the inner surface 10 of the casing 1.

[0077] As a result, the heat shield 7 capable of suppressing the transfer of heat from the power module 40 to the control board 6 can be realized with a simple configuration such as the heat shield plate 70.

[0078] (3) A power conversion device 100 according to a third aspect is the power conversion device 100 of (2), wherein the heat shield 70 may be formed from a thermally conductive material having a higher thermal conductivity in an in-plane direction of the heat shield 70 than the thermal conductivity in a thickness direction of the heat shield 70.

[0079] This makes it possible to further suppress the transfer of heat between the spaces within the casing 1 that are partitioned by the heat shield 70, while further suppressing the accumulation of heat in the heat shield 70.

[0080] (4) A power conversion device 100 according to a fourth aspect is the power conversion device 100 of (1), wherein the heat shield 7 may have a flat plate portion 71 arranged in the gap between the power module 40 and the control board 6, and a plurality of side wall plate portions 72 that surround the control board 6 from the in-plane direction of the flat plate portion 71 by connecting an outer edge portion 71a of the flat plate portion 71 to the inner surface 10 of the casing 1.

[0081] This makes it possible to further suppress the transfer of heat from the space on the power module 40 side to the space on the control board 6 side due to thermal convection.

[0082] (5) A power conversion device 100 according to a fifth aspect is the power conversion device 100 of (4), wherein the flat plate portion 71 and the side wall plate portion 72 may be formed from a thermally conductive material having a higher thermal conductivity in the in-plane direction of the flat plate portion 71 and the side wall plate portion 72 than the thermal conductivity in the thickness direction of the flat plate portion 71 and the side wall plate portion 72.

[0083] This makes it possible to better prevent heat from moving between the spaces within the casing 1 separated by the heat shield 7, while also better preventing heat from remaining in the flat plate portion 71 and side wall plate portion 72 of the heat shield 7. [Explanation of symbols]

[0084] 1... casing 1a... input side 1b... output side 2... external input conductor 3... capacitor 3a... main body 3b... connection conductor 3p... positive terminal 3n... negative terminal 4... power conversion section 5... cooler 6... control board 7... heat shield 8... current sensor 10... inner surface 11... top surface 13... side surface 40... power module 41... base plate 41a... front surface 41b... rear surface 42... circuit board 43... external output conductor 44... case 45... insulating section 51... base 51a... joint surface 51b... heat dissipation surface 52... heat dissipation fin 70... heat shield 70a, 71a, 72a... outer edge 71... flat plate portion 72... side wall plate portion 100... power conversion device 421... insulating plate 421a... first surface 421b... second surface 422... Surface pattern 422a... First surface pattern 422b... Second surface pattern 422c... Third surface pattern 423... Power semiconductor element 423a... First power semiconductor element 423b... Second power semiconductor element 424... Back surface pattern B... Bolt R1... First space R2... Second space Rp... Potting space S... Bonding material W... Liquid refrigerant Wb... Bonding wire

Claims

1. A casing; A capacitor housed in the casing; a power module housed in the casing and converting a DC voltage from the capacitor into an AC voltage; a cooler for cooling the power module; a control board that is accommodated in the casing with a gap between the power module and the control board, and that controls the drive of the power module; a heat shield housed in the casing and disposed between the power module and the control board; Equipped with the heat shield abuts against an inner surface of the casing to divide an interior of the casing into a space in which the power module is disposed and a space in which the control board is disposed, the heat shield has a heat shield plate disposed in the gap between the power module and the control board, An outer edge of the heat shield abuts against the inner surface of the casing, The heat shield is formed of a thermally conductive material having a higher thermal conductivity in an in-plane direction of the heat shield than in a thickness direction of the heat shield, The heat shield is a power conversion device in which many sheets of graphene are laminated together.

2. The heat shielding portion is a flat plate portion disposed in the gap between the power module and the control board; a plurality of side wall plate portions that connect an outer edge portion of the flat plate portion to the inner surface of the casing to surround the control board from an in-plane direction of the flat plate portion; The power converter according to claim 1 .

3. The power conversion device according to claim 2, wherein the flat plate portion and the side wall portion are formed from a thermally conductive material having a higher thermal conductivity in an in-plane direction of the flat plate portion and the side wall portion than a thermal conductivity in a thickness direction of the flat plate portion and the side wall portion.

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