Power conversion device

Abstract

A power conversion device includes: a first power circuit portion and a second power circuit portion each having a power semiconductor element and a plurality of conductor portions sandwiching the power semiconductor element and connected to an emitter and a collector of the power semiconductor element, respectively; and a flow path forming body accommodating the first and second power circuit portions and allowing a refrigerant to flow, the conductor portions on the emitter side of the first power circuit portion being arranged opposite to the conductor portions on the collector side of the second power circuit portion, and the conductor portions on the emitter side of the first power circuit portion and the conductor portions on the collector side of the second power circuit portion being connected by a plurality of electrically conductive fins in contact with the refrigerant.

Description

Technical Field

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

[0002] In recent years, in response to the increasing amount of electricity converted by power conversion devices, there is a need for miniaturization and weight reduction in automobiles. Therefore, continuous technological improvements are being made to reduce the increase in size and weight of power conversion devices while increasing their output power. In addition, compared with industrial power conversion devices, automotive power conversion devices are used in environments with large temperature variations. Therefore, devices that can maintain high reliability even in high-temperature environments are required.

[0003] Therefore, when a power conversion device performs power conversion, it needs to perform switching operations, that is, the semiconductor modules of the upper and lower arms constituting the inverter circuit repeatedly switch between blocking and conducting states. During this time, the transient current flowing through the upper and lower arms is affected by the parasitic inductance of the wiring, which becomes the cause of surge voltage. As a result, the losses of the semiconductor modules increase, and the temperature of the internal chips rises. For power conversion devices with high reliability, it is important to simultaneously reduce the inductance that causes this temperature rise and improve the cooling performance to suppress the temperature rise.

[0004] As background technology for this application, Patent Document 1 is known. In the cooling structure of the semiconductor device in Patent Document 1, two semiconductor elements are arranged opposite each other with an output electrode between them, and a heat sink is arranged on the opposite side of the output electrode relative to the semiconductor elements. The output electrode includes an element mounting portion and a heat transfer portion, the element mounting portion being electrically connected to the two semiconductor elements and formed of a conductive material. The heat transfer portion extends from the element mounting portion toward the heat sink. The disclosed technology reduces inductance, which is a cause of temperature rise, and achieves excellent cooling efficiency.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: International Publication No. 2011 / 064841 Summary of the Invention

[0008] In the method described in Patent Document 1, multiple input electrodes are arranged in parallel, and switching losses can be reduced by eliminating parasitic inductance between the input electrodes. However, since the heat transfer section is connected to the heat sink via an insulating member, the cooling efficiency of the insulating member in the heat dissipation path may be reduced. In view of this, the object of the present invention is to provide a power conversion device that simultaneously achieves improved cooling performance through two-sided cooling that eliminates the insulating member in the heat dissipation path and reduced inductance to suppress switching losses, thereby increasing power.

[0009] The power conversion device includes: a first power circuit section and a second power circuit section, each having a power semiconductor element and a plurality of conductor sections sandwiching the power semiconductor element and connected to the emitter and collector of the power semiconductor element respectively; and a flow path forming body that houses the first power circuit section and the second power circuit section and supplies refrigerant flow, wherein the conductor section on the emitter side of the first power circuit section and the conductor section on the collector side of the second power circuit section are arranged opposite to each other, and the conductor section on the emitter side of the first power circuit section and the conductor section on the collector side of the second power circuit section are connected by a plurality of conductive fins in contact with the refrigerant.

[0010] Invention Effects

[0011] According to the present invention, a power conversion device can be provided that simultaneously improves cooling performance, reduces inductance, and increases power. Attached Figure Description

[0012] Figure 1 This is a cross-sectional view of a power conversion device according to one embodiment of the present invention.

[0013] Figure 2 This is a top view of the substrate (lower layer) of the first power circuit section according to one embodiment of the present invention.

[0014] Figure 3 From Figure 2 The top view of the molded resin has been removed.

[0015] Figure 4 This is a top view of the power module.

[0016] Figure 5 This is a 3D view of the power module.

[0017] Figure 6 This is the main view of the power module.

[0018] Figure 7 This is a top view of the substrate (upper layer) of the second power circuit section according to one embodiment of the present invention.

[0019] Figure 8 From Figure 7 The top view of the molded resin has been removed.

[0020] Figure 9 This is a top view of a power conversion device according to one embodiment of the present invention. Detailed Implementation

[0021] (One embodiment of the present invention)

[0022] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, the present invention is not limited to the following embodiments, and the technical concept of the present invention can also be realized by combining other known constituent elements. Furthermore, the same reference numerals are used to label the same elements in each figure, and repeated descriptions are omitted.

[0023] Furthermore, for ease of understanding, the positions, sizes, shapes, and extents of the constituent elements shown in the accompanying drawings may not represent their actual positions, sizes, shapes, or extents. Therefore, the present invention is not necessarily limited to the positions, sizes, shapes, and extents disclosed in the accompanying drawings.

[0024] Figure 1 This is a cross-sectional view of a power conversion device according to one embodiment of the present invention.

[0025] The power conversion device 100 is a power conversion device that converts direct current (DC) power from a battery or the like into alternating current (AC) power and supplies it to an electric motor. Figure 1 The diagram shows the configuration of the upper and lower arm circuits for a single phase.

[0026] The power conversion device 100 includes: a first substrate 3001 having a first power circuit section 201; a second substrate 3002 having a second power circuit section 202; a capacitor 40 for smoothing the voltage applied to the power conversion device 100; and a flow path forming body 25 for supplying refrigerant to cool the entire power conversion device 100.

[0027] The first power circuit section 201 connects the IGBT 10, which is a power semiconductor element, to the emitter conductor plate 221 and the collector conductor plate 211 on the first power circuit side using soldering or the like. Similarly, the second power circuit section 202 connects the IGBT 10, which is a power semiconductor element, to the emitter conductor plate 222 and the collector conductor plate 212 on the second power circuit side using soldering or the like.

[0028] The first power circuit section 201 and the second power circuit section 202 are composed of an IGBT 10, an emitter conductor plate 221 (222), and a collector conductor plate 211 (212). Furthermore, the first power circuit section 201 and the second power circuit section 202 are disposed in power module assembly holes 303 formed for mounting on substrates 30 (3001, 3002) such as printed circuit boards. The first power circuit section 201 and the second power circuit section 202, mounted on the substrates 30 (3001, 3002), are sealed and fixed by molding resin 23. This eliminates the need for complex-shaped busbars, improving productivity.

[0029] The substrate 30 (3001, 3002) has multiple conductor layers made of copper or the like, and the portions outside the conductor layers are made of insulating components such as glass epoxy resin. Conductors are formed in each layer through through-holes 302. As a result, the cross-sectional area of ​​the conductors is increased, which can reduce inductance.

[0030] like Figure 1 As shown, the power conversion device 100 is configured with two layers: a first power circuit section 201 as the lower layer and a second power circuit section 202 as the upper layer. The flow path forming body 25 is formed to cover both power circuit sections. In addition, the flow path forming body 25 is composed of three flow path forming bodies: an upper surface flow path forming body 251, a lower surface flow path forming body 252, and an intermediate flow path forming body 253.

[0031] The upper surface flow path forming 251 forms a flow path together with the second power circuit section 202 and the second substrate 3002. Refrigerant flowing upwards through the upper surface flow path forming 251 enters from the flow path inlet 26 and flows through the through hole 301a to the intermediate flow path forming 253. As a result, the upper surfaces of the second power circuit section 202 and the second substrate 3002 are cooled.

[0032] The intermediate flow path forming 253 forms a flow path together with the second power circuit section 202 and the second substrate 3002, as well as the first power circuit section 201 and the first substrate 3001. Refrigerant flowing into the intermediate flow path forming 253 enters from the upper surface flow path forming 251 through a through hole 301a, and connects to the lower surface flow path forming 252 through a through hole 301b. As a result, the lower surfaces of the second power circuit section 202 and the second substrate 3002, as well as the upper surfaces of the first power circuit section 201 and the first substrate 3001, are cooled.

[0033] The lower surface flow path forming 252 forms a flow path together with the first power circuit section 201 and the first substrate 3001. Refrigerant flowing down the lower surface flow path forming 252 enters from the intermediate flow path forming 253 through the through hole 301b and exits to the outside of the flow path forming 252 via the flow path outlet 27. As a result, the lower surfaces of the first power circuit section 201 and the first substrate 3001 are cooled.

[0034] According to Figure 1 The configuration described herein forms a refrigerant path 254, and the refrigerant flows inside the flow path forming body 25 along the arrow of the refrigerant path 254. Cooling fins 24 are provided in the middle of the refrigerant path 254 to promote heat dissipation of the first power circuit section 201 and the second power circuit section 202.

[0035] The cooling fins 24 are conductive, electrically connecting the emitter conductor plate 221 on the first power circuit side to the collector conductor plate 212 on the second power circuit side. This allows for the connection of the power circuit sections with the shortest possible distance, contributing to a reduction in inductance. Furthermore, since it is not necessary to arrange the first power circuit section 201 and the second power circuit section 202 side-by-side in a planar direction, it also contributes to the miniaturization of the power conversion device 100.

[0036] The capacitor 40 is disposed outside the flow path forming body 25, with a positive terminal 401 connected to the first substrate 3001 and a negative terminal 402 connected to the second substrate 3002. This prevents corrosion of electronic components caused by contact with the refrigerant.

[0037] Figure 2 This is a top view of the substrate (lower layer) of the first power circuit section according to one embodiment of the present invention. Furthermore, X-X' is used to indicate... Figure 1 The location of the cross section.

[0038] The first substrate 3001 is composed of a first power circuit section 201, a positive power terminal conductor 31 having a positive power terminal 311, an AC output terminal conductor 33 having an AC output terminal 331, and a control circuit 50 for generating control signals.

[0039] On the first substrate 3001, a capacitor 40 is mounted between the first power circuit section 201 and the positive power supply terminal 311. Multiple capacitors 40 are constructed of ceramic capacitors or the like. Each capacitor 40 has a positive terminal 401 and a negative terminal 402. Figure 1 A positive terminal 401 is connected to the first substrate 3001. The capacitor 40 is mounted side by side with the first power circuit section 201, thereby expanding the current path from the capacitor 40 to the first power circuit section 201, thus reducing inductance.

[0040] The first power circuit section 201 is molded from molding resin 23, and a portion of the emitter conductor plate 221 on the first power circuit side is not molded, exposing it to the refrigerant flow path. Furthermore, a plurality of cooling fins 24 are formed on the exposed surface of this portion. As a result, the heat dissipation effect of the first power circuit section 201 is improved.

[0041] Figure 3 From Figure 2 The top view of the molded resin has been removed.

[0042] The control circuit 50 is arranged adjacent to the first power circuit section 201, and the control signal wiring 51, which is connected to the first power circuit section 201 from the substrate wiring 52 in the flow path via lead bonding or the like, reduces the inductance of the control signal wiring 51, prevents the degradation of component driving performance, and thus prevents the increase of losses.

[0043] In the first substrate 3001, a through hole 301b for refrigerant flow is provided between the first power circuit section 201 and the AC output terminal 331. The through holes 301b are formed in a circular or similar shape, and multiple through holes 301b are arranged side-by-side opposite the first power circuit section 201. The refrigerant communicates with all the conductor layers provided on both sides of the substrate 3001 through the through holes 301b, enabling two-sided cooling of the first power circuit section 201.

[0044] Figure 4 This is a top view of the power module. Figure 5 It is its three-dimensional image. Figure 6 This is its main view.

[0045] The power module 20 constitutes the upper or lower arm circuit of one phase in a power conversion device that converts DC power into AC power. Furthermore, the power module 20 is composed of an IGBT 10, a diode 11, a collector conductor plate 21, and an emitter conductor plate 22.

[0046] The IGBT 10 is plate-shaped, having a main electrode 101 and a control electrode 102 that controls the main current flowing to the main electrode 101. The collector conductor plate 21 and emitter conductor plate 22 are formed of copper, and the IGBT 10 and diode 11 are held from both sides by the collector conductor plate 21 and emitter conductor plate 22 respectively. The IGBT 10 and diode 11 are connected to the collector conductor plate 21 and emitter conductor plate 22 by means of a metal bonding material 12 such as solder.

[0047] In the power conversion device 100 of this embodiment, the first power circuit section 201 and the second power circuit section 202 are each composed of power modules 20 constructed as described above. In the first power circuit section 201, the collector conductor plate 21 and the emitter conductor plate 22 correspond to the first power circuit-side collector conductor plate 211 and the first power circuit-side emitter conductor plate 221, respectively. In the second power circuit section 202, the collector conductor plate 21 and the emitter conductor plate 22 correspond to the second power circuit-side collector conductor plate 212 and the second power circuit-side emitter conductor plate 222, respectively. Furthermore, in Figure 1 In the diagram, diode 11 is omitted.

[0048] Figure 7 This is a top view of the substrate (upper layer) of the second power circuit section according to one embodiment of the present invention. Furthermore, X-X' is used to indicate... Figure 1 The location of the cross section.

[0049] The second substrate 3002 comprises a second power circuit section 202, a negative power terminal conductor 32 having a negative power terminal 321, an AC output terminal conductor 33 having an AC output terminal 331, and a control circuit 50 for generating control signals. Between the second power circuit section 202 and the negative power terminal 321, multiple through holes 301a for refrigerant flow are arranged side-by-side relative to the second power circuit section 202.

[0050] The second substrate 3002 is formed with the same structure as the first substrate 3001. Regarding the arrangement and structure of the first substrate 3001 and the second substrate 3002, the following method is used... Figure 2 and Figure 7 Explanation is provided through comparison. Figure 2 The first substrate 3001 shown and Figure 7 The second substrate 3002 shown has a point-symmetric shape with respect to each other, except for the arrangement of the capacitor 40. That is, the positive power terminal conductor 31 of the first substrate 3001 corresponds to the AC output terminal conductor 33 of the second substrate 3002, and the AC output terminal conductor 33 of the first substrate 3001 corresponds to the negative power terminal conductor 32 of the second substrate 3002. In this way, the upper and lower arms constituting the power conversion device 100 are manufactured with the same shape and structure, thereby improving productivity.

[0051] Moreover, such as Figure 1 As shown, the first substrate 3001 and the second substrate 3002 are overlapped and arranged in an upper and lower layer configuration, thereby simultaneously achieving a shortened wiring path and cooling by the refrigerant flowing into the flow path forming body 25. Therefore, it not only contributes to the effect of increased power achieved by simultaneously improving cooling performance and reducing inductance, but also contributes to the miniaturization of the overall device.

[0052] In the second substrate 3002, the second power circuit side collector conductor plate 212 is arranged opposite to the first power circuit side emitter conductor plate 221, and the first power circuit side emitter conductor plate 221 and the second power circuit side collector conductor plate 212 are connected by a plurality of conductive cooling fins 24. Figure 1 This results in a configuration where the IGBT 10 of the first power circuit section 201 is opposite to the diode 11 of the second power circuit section 202, and the diode 11 of the first power circuit section 201 is opposite to the IGBT 10 of the second power circuit section 202. This arrangement shortens the transient current path during the switching of the power conversion device 100, allowing current to flow between the first power circuit section 201 and the second power circuit section 202, thereby reducing inductance.

[0053] Capacitor 40 is located on the second substrate 3002 between the second power circuit section 202 and the negative power supply terminal 321. The negative terminal 402 of capacitor 40 is connected to the second substrate 3002, and the negative terminal 402 is arranged opposite to the positive terminal 401. Figure 1 Therefore, the current path flowing out of capacitor 40 to the first power circuit section 201 is opposite to the current path flowing into capacitor 40 from the second power circuit section 202, which can reduce inductance.

[0054] Furthermore, in the configuration described above, in the power conversion device 100, the electrical energy required to drive the motor from the battery is supplied to the first power circuit section 201 and the second power circuit section 202, controlling the AC power output from the AC output terminal 331 provided on the AC output terminal conductor 33. When the power conversion device 100 is switched on or off, the current flowing from the positive terminal 401 of the capacitor 40 flows from the first power circuit section 201 through the conductive cooling fins 24 to the second power circuit section 202, and then flows into the negative terminal 402. This shortens the transition current path during switching and reduces inductance.

[0055] Furthermore, a heat dissipation path is formed from the semiconductor elements (IGBT 10, diode 11) of the first power circuit section 201 and the second power circuit section 202 to the conductive cooling fins 24 without the use of insulating components, and direct cooling by refrigerant such as oil. This suppresses the increase in thermal resistance and aims to increase the power of the power conversion device 100. In addition, by positioning the through holes 301a and 301b close to the molding resin 23, the refrigerant path 254 can be shortened, thereby simultaneously reducing pressure loss and improving cooling efficiency.

[0056] Figure 9 This is a top view of a power conversion device according to one embodiment of the present invention. Furthermore, X-X' is used to indicate... Figure 1 The location of the cross section.

[0057] The flow path forming body 25 is arranged to surround the molding resin 23 and the through holes 301a and 301b, and the capacitor 40 and the control circuit 50 are formed on the outside of the flow path forming body 25. This prevents corrosion of electronic components caused by refrigerant contact. On the other hand, the first power circuit section 201, the second power circuit section 202, and the control signal wiring 51 are formed within the flow path forming area and are protected from electrical influences caused by refrigerant contact by passing through the molding resin 23.

[0058] According to one embodiment of the present invention described above, the following effects are achieved.

[0059] (1) The power conversion device 100 includes: a first power circuit section 201 and a second power circuit section 202, each having an IGBT 10 as a power semiconductor element, and multiple conductor sections (emitter conductor plate 221, collector conductor plate 211, emitter conductor plate 222, collector conductor plate 212, etc.) that sandwich the IGBT 10 and are respectively connected to the emitter and collector of the IGBT 10. The device includes a flow path forming body 25, which houses the first power circuit section 201 and the second power circuit section 202 and allows refrigerant to flow through it. The emitter-side conductor 221 of the first power circuit section 201 and the collector-side conductor 212 of the second power circuit section 202 are arranged opposite to each other. The emitter-side conductor 221 of the first power circuit section 201 and the collector-side conductor 212 of the second power circuit section 202 are connected by a plurality of conductive cooling fins 24 in contact with the refrigerant. This arrangement enables a power conversion device that simultaneously improves cooling performance and reduces inductance while increasing power output.

[0060] (2) The power semiconductor element is composed of IGBT 10 and diode 11, and is configured such that IGBT 10 of the first power circuit section 201 is opposite to diode 11 of the second power circuit section 202, and diode 11 of the first power circuit section 201 is opposite to IGBT 10 of the second power circuit section 202. Due to this arrangement, the inductance can be reduced.

[0061] (3) The flow path forming body 25 is composed of an upper surface flow path forming body 251 that forms a flow path on the upper surface of the first power circuit section 201, a lower surface flow path forming body 252 that forms a flow path on the lower surface of the second power circuit section 202, and an intermediate flow path forming body 253 that forms a flow path between the first power circuit section 201 and the second power circuit section 202. With this arrangement, the refrigerant can be connected and the upper and lower power circuit sections 201 and 202 can be cooled simultaneously.

[0062] (4) The first power circuit section 201 and the second power circuit section 202 are respectively mounted on the first substrate 3001 and the second substrate 3002, which have conductor layers that are electrically connected to the conductor section. As a result of this arrangement, the magnitude of the height direction formed by the first power circuit section 201 and the second power circuit section 202 arranged as upper and lower layers is suppressed.

[0063] (5) The first substrate 3001 and the second substrate 3002 are configured with the same shape. As a result of this arrangement, productivity is improved.

[0064] (6) The conductor layer of the first substrate 3001 and the conductor layer of the second substrate 3002 are arranged opposite to each other and are respectively connected to the positive terminal 401 and the negative terminal 402 of the capacitor 40 disposed outside the flow path forming body 25. Due to this arrangement, the transition current path during switching is shortened and the inductance is reduced.

[0065] (7) The internal flow paths of the upper surface flow path forming body 251 and the lower surface flow path forming body 252 are connected to each other through the internal flow path of the intermediate flow path forming body 253. As a result of this arrangement, the power circuit sections 201 and 202 of the upper and lower layers can be cooled simultaneously.

[0066] The present invention has been described above, but RC-IGBT can also be applied to IGBT10, thereby further contributing to the reduction of losses of semiconductor elements used to improve the fuel economy of HEVs and EVs and the miniaturization of the power conversion device 100.

[0067] Furthermore, the invention can be modified by deleting, replacing, or adding other components without departing from the technical concept of the invention, and its form is also included within the scope of the invention.

[0068] Explanation of reference numerals in the attached figures

[0069] 10: IGBT,

[0070] 101: Main electrode,

[0071] 102: Control electrode,

[0072] 11: Diode,

[0073] 12: Metal bonding materials,

[0074] 20: Power module

[0075] 201: First Power Circuit Section

[0076] 202: Second Power Circuit Section

[0077] 21: Collector conductor plate,

[0078] 211: Collector conductor plate on the first power circuit side.

[0079] 212: Collector conductor plate on the second power circuit side.

[0080] 22: Emitter conductor plate,

[0081] 221: Emitter conductor plate on the first power circuit side.

[0082] 222: Emitter conductor plate on the second power circuit side.

[0083] 23: Molding resin,

[0084] 24: Conductive fins,

[0085] 25: Flow path forming body,

[0086] 251: Upper surface flow path forming body,

[0087] 252: Lower surface flow path forming body,

[0088] 253: Intermediate flow path forming body,

[0089] 254: Refrigerant path,

[0090] 26: Flow path entrance,

[0091] 27: Flow path outlet,

[0092] 30: substrate,

[0093] 301a, 301b: Through holes,

[0094] 302: Through hole,

[0095] 303: Power module assembly hole,

[0096] 3001: 1st substrate,

[0097] 3002: 2nd substrate,

[0098] 31: Positive power supply terminal conductor,

[0099] 311: Positive power terminal

[0100] 32: Negative power supply terminal conductor.

[0101] 321: Negative power terminal

[0102] 33: AC output terminal conductor,

[0103] 331: AC output terminal,

[0104] 40: Capacitor,

[0105] 401: Positive extreme,

[0106] 402: Negative extreme case,

[0107] 50: Control circuit,

[0108] 51: Control signal wiring,

[0109] 52: In-circuit substrate wiring,

[0110] 100: Power conversion device.

Claims

1. A power conversion device comprising: The first power circuit section and the second power circuit section each have a power semiconductor element and a plurality of conductor sections sandwiching the power semiconductor element and connected to the emitter and collector of the power semiconductor element, respectively; and The flow path form houses the first power circuit section and the second power circuit section, and provides refrigerant flow. The conductor portion on the emitter side of the first power circuit section and the conductor portion on the collector side of the second power circuit section are arranged opposite to each other. The conductor portion on the emitter side of the first power circuit section and the conductor portion on the collector side of the second power circuit section are connected by a plurality of conductive fins in contact with the refrigerant.

2. The power conversion device according to claim 1, wherein, The power semiconductor element is composed of an IGBT and a diode, and is configured such that the IGBT of the first power circuit section is opposite to the diode of the second power circuit section, and the diode of the first power circuit section is opposite to the IGBT of the second power circuit section.

3. The power conversion device according to claim 1, wherein, The flow path forming body is composed of an upper surface flow path forming body that forms a flow path on the upper surface of the first power circuit section, a lower surface flow path forming body that forms a flow path on the lower surface of the second power circuit section, and an intermediate flow path forming body that forms a flow path between the first power circuit section and the second power circuit section.

4. The power conversion device according to claim 1, wherein, The first power circuit section and the second power circuit section are respectively mounted on a first substrate and a second substrate having a conductor layer electrically connected to the conductor section.

5. The power conversion device according to claim 4, wherein, The first substrate and the second substrate are configured with the same shape.

6. The power conversion device according to claim 5, wherein, The conductor layers of the first substrate and the second substrate are arranged opposite to each other and are respectively connected to the positive and negative terminals of a capacitor disposed outside the flow path forming body.

7. The power conversion device according to claim 3, wherein, The flow paths inside the upper surface flow path forming body and the lower surface flow path forming body are connected to each other through the flow paths inside the intermediate flow path forming body.

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