JP2012028402A - Power unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power unit capable of detecting an increase in a voltage of an air-cooling heat sink, and ensuring noise resistance.SOLUTION: An inverter circuit unit 30 comprises a semiconductor device 10 having a semiconductor module 22 including semiconductor elements, and a metallic heat sink 11 integrally provided with the semiconductor module 22 and radiating the heat of the semiconductor module 22 into air; and a case 38 storing a plurality of the semiconductor devices 10 so as to be integrated. A part of the case 38 is formed by metal, and the rest part is formed by a resin material. The plurality of the semiconductor devices 10 are stored in the case 38 while a part of the case 38 formed by metal contacts with the heat sink 11. A part of the case 38 formed by metal is electrically coupled to a vehicle side member through an earth cable.

Description

  The present invention relates to a power unit including an air-cooled heat sink for cooling a semiconductor module.

  A conventional power unit is composed of a plurality of semiconductor devices having a cooling system in which heat generated by a power semiconductor module incorporating a semiconductor element is dissipated by an air-cooled heat sink (see, for example, Patent Document 1). The power unit of Patent Document 1 includes a semiconductor device in which a plurality of power semiconductor modules and a plurality of air-cooled heat sinks are stacked, and further includes a fan that blows cooling air to the air-cooled heat sink. An insulating substrate made of ceramic, for example, is interposed between the power semiconductor module and the air-cooled heat sink, thereby exhibiting an insulating function.

  When mounting a power unit having such a structure on a vehicle or the like, since the cooling fluid is air, a waterproof structure is not required, from the viewpoint of downsizing and weight reduction for improving mountability, It has been proposed to house the power unit in a resin case.

JP 2008-278576 A

  However, when the conventional power unit is housed in a resin case, a high voltage is applied to the heat sink itself when the insulation performance is reduced due to, for example, a crack in the insulating substrate between the power semiconductor module and the air-cooled heat sink. In some cases, it is necessary to ensure safety in such a situation.

  In addition, when a power unit composed of a plurality of semiconductor devices is housed in a resin case, the resin case does not have an electromagnetic shielding function, so that the control circuit malfunctions due to noise from the power semiconductor module. There is a problem of getting.

  Therefore, the present invention has been made in view of the above problems, and an object thereof is to provide a power unit capable of detecting high voltage of an air cooling heat sink and ensuring noise resistance.

The present invention employs the following technical means to achieve the above object. That is, the invention of the power unit according to claim 1 includes a semiconductor module incorporating a semiconductor element, and a metal heat sink that is provided integrally with the semiconductor module and radiates heat of the semiconductor module into the air. A semiconductor device and a case for housing a plurality of semiconductor devices in an integrated manner,
The case is partly made of metal and the rest is made of resin material.
The plurality of semiconductor devices are accommodated in the case in a state where a part of the case made of metal is in contact with the heat sink,
A part of the case formed of metal is electrically connected to a vehicle-side member.

  According to the present invention, a part of the case formed of metal is brought into contact with the heat sink and electrically connected to the vehicle-side member, so that the ground connection between the heat sink and the vehicle-side member is not employed in a complicated configuration. The electrical condition of the heat sink can be detected. Furthermore, noise propagation from the semiconductor device can be suppressed by a part of the case formed of metal. Therefore, it is possible to provide a power unit capable of detecting high voltage of the air cooling heat sink and ensuring noise resistance.

  According to a second aspect of the present invention, in the first aspect, a part of the case formed of metal is a lid portion that covers one surface of the case, and the lid portion and the heat sink are fastened by screwing means. Features. According to the present invention, by providing the fastening force by the screwing means, a conductive path and a heat transfer path from the heat sink to the lid portion are surely formed. Therefore, it is possible to more reliably construct a structure that achieves both high voltage detection of the air cooling heat sink and ensuring noise resistance.

  According to a third aspect of the present invention, in the second aspect, the heat sink protrudes from the substrate portion so as to form a row at intervals in the thickness direction of the substrate portion thermally coupled to the semiconductor module. A plurality of first fins and fins protruding from the substrate portion on the outer side further than the first fin located on the outermost side in the thickness direction, wherein the thick portion has a larger thickness dimension than the first fin. And a second fin. The thick portion and the lid portion of the second fin are fastened by screwing means.

  According to the present invention, since the thick part of the second fin is utilized for exhibiting the function of the screwing means, there is an effect that it is easy to ensure a shape capable of exhibiting the fixing function between the heat sink and the lid. Further, when the female thread portion of the screwing means is formed in the thick portion of the second fin, a predetermined number of screw threads or the like are required, so that other parts and components for screw tightening are separately required. At least, the internal thread portion capable of exhibiting the screw tightening function can be ensured, and the fastening force can be improved.

  According to a fourth aspect of the present invention, in the semiconductor device according to any one of the first to third aspects, the semiconductor device energizes two heat sinks that sandwich the semiconductor module from both sides and a force that sandwiches the semiconductor module by elastic force. And the two heat sinks are sandwiched by the elastic members so as to approach each other. According to the present invention, since the two heat sinks are integrally formed by sandwiching both heat sinks sandwiching the semiconductor module from both sides by the elastic member, the degree of contact between the lid and each heat sink is increased, and the two are closely attached. It is possible to improve the performance.

  According to a fifth aspect of the present invention, in any one of the first to fourth aspects of the present invention, the vehicle-side member is one of cases made of metal. The part is connected to a portion projecting from the air blowing passage in a direction orthogonal to the air blowing direction by the blowing means. According to this invention, the said site | part electrically connected with the member by the side of a vehicle is set to the site | part which does not interfere with the ventilation path outside a ventilation path. Thereby, the connection between the vehicle-side member and a part of the case formed of the metal can be performed in a state where the air passage does not get in the way, which contributes to the improvement of workability related to the connection.

  According to a sixth aspect of the present invention, in any one of the first to fifth aspects, a part of the case formed of metal is a lid that covers one surface of the case, and the lid is a semiconductor It is characterized by being arranged so as to face a control board constituting a control circuit for controlling the operation of the element. According to the present invention, it is possible to suppress the noise from each semiconductor device from propagating to the control board by the metal lid, and it is possible to prevent malfunction of electronic components for controlling the semiconductor device, deterioration of EMC characteristics, etc. Can be suppressed. Further, the heat generated by each heat sink can be prevented from being transferred to the control board by the metal lid portion, so that the deterioration of the electronic component can be reduced and the life can be ensured.

It is a schematic diagram which shows the state which mounted the inverter apparatus provided with the power unit to which this invention is applied to the vehicle. It is a circuit diagram of the inverter apparatus of 1st Embodiment. 1 is an exploded perspective view illustrating a configuration of a semiconductor device according to a first embodiment. 1 is a perspective view illustrating a configuration of a semiconductor device according to a first embodiment. It is a perspective view which shows the state which accommodated the six semiconductor devices in the case. It is a perspective view which shows the external appearance of the inverter apparatus of 1st Embodiment. It is sectional drawing which shows the positional relationship of the case which accommodated the semiconductor device, and a control board.

  A plurality of modes for carrying out the present invention will be described below with reference to the drawings. In each embodiment, parts corresponding to the matters described in the preceding embodiment may be denoted by the same reference numerals, and redundant description may be omitted. When only a part of the configuration is described in each mode, the other modes described above can be applied to the other parts of the configuration. Not only combinations of parts that clearly indicate that each embodiment can be specifically combined, but also combinations of the embodiments even if they are not clearly indicated unless there is a problem with the combination. Is also possible.

(First embodiment)
The semiconductor device according to the present invention can be applied to an inverter device as a motor driving device that drives a high-output motor. This inverter device is a device that performs bidirectional conversion between DC power and AC power, for example, a U-phase, V-phase, and W-phase three-phase inverter device, a hybrid vehicle that uses an AC motor, a fuel cell vehicle, Installed in electric vehicles.

  1st Embodiment demonstrates the example which applied the semiconductor device 10 to the inverter apparatus 1 which has the three-phase inverter circuit which drives the motor 3 for driving | running | working. FIG. 1 is a schematic diagram showing a state in which an inverter device 1 to which a semiconductor device 10 is applied is mounted on a vehicle. FIG. 2 is a circuit diagram of the inverter device 1 to which the semiconductor device 10 is applied.

  As shown in FIG. 1, the inverter device 1 is connected to a traveling motor 3 mounted on the front side of the vehicle in a wired manner so as to be output, and is mounted on the rear side of the vehicle so as to be adjacent to the battery 4. The inverter device 1 is air-cooled by supplying the semiconductor device 10 with air blown by a fan 9 serving as a blowing means for blowing air through a predetermined ventilation path formed by a duct. The air that cools the inverter device 1 is taken from the outside of the vehicle or the vehicle interior, passes through the semiconductor device 10, and is discharged outside the vehicle. In this way, the inverter device 1 can be kept at a temperature at which a predetermined function can be exhibited.

  As shown in FIG. 2, the inverter circuit (inverter device 1) includes six semiconductor modules 22a, 22b, 22c, 22d, 22e, and 22f (hereinafter referred to as six semiconductor modules) for three-phase power conversion. The power module 2 includes a power module 2 that may be simply referred to as a semiconductor module 22 when referring to an arbitrary semiconductor module, capacitors 5 and 6, resistors 7 and 8, and a control circuit 100. A battery 4 is connected to the input side of the inverter circuit. A motor 3 is connected to the output side of the inverter circuit.

  The power module 2 is controlled by the control circuit 100, and is configured with elements for configuring an inverter circuit that converts DC power output from the battery 4 into AC power and supplies the AC power to the motor 3. The power module 2 includes IGBTs 20a, 20b, 20c, 20d, 20e, and 20f (switching elements) and free wheeling diodes 21a, 21b, 21c, 21d, 21e, and 21f. Each semiconductor module 22 includes one IGBT and one freewheeling diode.

  The IGBTs 20a and 20b, the IGBTs 20c and 20d, and the IGBTs 20e and 20f are respectively connected in series. The collectors of the IGBTs 20 a, 20 c and 20 e on the upper arm side are connected to the positive terminal side of the battery 4, and the emitter of the IGBT 20 d on the lower arm side is connected to the negative terminal side of the battery 4. The emitters of the IGBTs 20b and 20f on the lower arm side are connected to the negative terminal side of the battery 4 via resistors 7 and 8, respectively. The gates of the IGBTs 20 a to 20 f are connected to the control circuit 100. The emitters of the IGBTs 20a, 20c, and 20e are connected to the control circuit 100. Furthermore, the connection point between the IGBT 20 a and the IGBT 20 b, the connection point between the IGBT 20 c and the IGBT 20 d, and the connection point between the IGBT 20 e and the IGBT 20 f are connected to the motor 3. Freewheeling diodes 21a to 21f are connected between the collectors and emitters of the IGBTs 20a to 20f, respectively.

  The resistors 7 and 8 are elements that convert a current supplied from the power module 2 to the motor 3 into a voltage. One end of the resistor 7 is connected to the emitter of the IGBT 20 b, and the other end is connected to the negative terminal of the battery 4. One end of the resistor 8 is connected to the emitter of the IGBT 20 f and the other end is connected to the negative terminal side of the battery 4. Further, both ends of the resistors 7 and 8 are connected to the control circuit 100.

  Capacitor 5 smoothes the output voltage of battery 4. The capacitor 6 suppresses noise entering the power module 2 and detects a voltage applied from the battery 4 to the power module 2. The capacitor 5 and the capacitor 6 are connected to the battery 4 in parallel. Both ends of the capacitor 6 are connected to the control circuit 100.

  The control circuit 100 is based on an external command, a current supplied to the motor 3 from the power module 2 detected by the resistors 7 and 8, and a voltage applied to the power module 2 from the battery 4 detected by the capacitor 6. Thus, the power module 2 is controlled. The control circuit 100 is connected to the power module 2, the resistors 7 and 8, and the capacitor 6.

  Next, the configuration of the semiconductor device 10 will be described with reference to FIGS. FIG. 3 is an exploded perspective view showing the configuration of the semiconductor device 10. FIG. 4 is a perspective view showing the configuration of the semiconductor device 10. As shown in FIG. 3, one semiconductor device 10 is arranged on each of the card-shaped semiconductor module 22 and both sides of the main body 226 (both sides of the main surfaces 221 and 222) so as to sandwich the semiconductor module 22 from both sides. Two heat sinks 11, and has a cooling mechanism capable of both-side cooling.

  The semiconductor module 22 incorporates IGBTs 20a to 20f and free wheeling diodes 21a to 21f, which are semiconductor elements, and has a main body 226 having a pair of opposed main surfaces 221 and 222, and protrudes outward from the main body 226. A collector-side electrode terminal 223, an emitter-side electrode terminal 224, and a control signal terminal 225.

  Further, an insulating substrate 12 made of ceramic is interposed between the main body 226 and the heat sink 11 of the semiconductor module 22, and further, good heat is provided between the insulating substrate 12, the heat sink 11 and the main body 226. Conductive silicon-based heat dissipation grease is applied. The insulating substrate 12 may be formed of an aluminum nitride film or a silicon rubber sheet, and the insulating substrate 12 and the heat dissipation grease may employ a heat dissipation film having insulating properties.

  The semiconductor elements of the IGBT and the free wheeling diode are joined to the inner main surface of the metal heat transfer plate 220 located on the main surface 221 side by a solder layer, and the remaining main surface of the semiconductor element has an opposite main surface. A metal heat transfer plate (not shown) located on the surface 222 side is joined by a solder layer. In this way, the anode and cathode of the freewheeling diode are connected to the IGBT collector and emitter in so-called reverse parallel (see FIG. 2). The metal heat transfer plate 220 and the metal heat transfer plate located on the main surface 222 side are electrically connected to the collector side electrode terminal 223 and the emitter side electrode terminal 224, respectively. Further, the solder layer may be replaced with another bonding function material.

  The main body portion 226 is a rectangular plate-shaped member made of, for example, an epoxy resin, and completely molds a semiconductor element. Is molded so as to be exposed. The collector-side electrode terminal 223 and the emitter-side electrode terminal 224 protrude from one side surface of the main body 226 in the direction X parallel to the main surfaces 221 and 222, and the plurality of control signal terminals 225 that are lead frame terminals are from the other side surface. Projecting in the opposite direction to the collector-side electrode terminal 223 and the like, it is connected to an electrode and the like formed on the gate of the IGBT.

  The heat sink 11 includes a plate-like substrate portion 110 that is thermally coupled to the main surfaces 221 and 222 of the semiconductor module 22, and a plurality of first portions that protrude from the substrate portion 110 in a right angle direction (corresponding to the fin protruding direction Z). 1 fin 112 and a member integrally formed of aluminum or copper. The first fins 112 are rectangular plate members that protrude from the side opposite to the main surface 111 of the substrate part 110, and a plurality of first fins 112 form rows at intervals in the thickness direction Y thereof. Are lined up like

  The heat sink 11 further includes two second fins 113. The second fin 113 is perpendicular to the substrate portion 110 on the outer side of the fins located on the outermost sides in both the thickness directions Y of the first fins 112 in a plurality of rows (fin projecting direction Z). It is a plate-shaped fin which protrudes in the direction. The second fin 113 is formed so as to be parallel to the first fin 112 and has a thick portion having a thickness dimension larger than that of the first fin 112. For example, the thick part of the second fin 113 has a thickness twice or more that of the first fin 112. The second fin 113 of the present embodiment is a plate having the same thickness as a whole, and the whole is a thick portion having a thickness dimension larger than that of the first fin 112. It may be formed only on a part of the two fins 113.

  The second fin 113 is a direction perpendicular to the thickness direction Y and parallel to the main surfaces 221 and 222 of the semiconductor module 22 ("direction X parallel to the main surface" shown in FIGS. 3 and 4). The length dimension is smaller than that of the first fin 112. Therefore, the second fin 113 is a fin whose lateral width dimension is shorter than that of the first fin 112 and is thicker than the first fin 112.

  Further, since the second fin 113 is positioned at the center of the substrate unit 110 in the direction X parallel to the main surface of the substrate unit 110 in FIG. 3, the second fin 113 does not protrude from the substrate unit 110 ( The finless portion 110 a) is provided on both sides of the second fin 113 in the “direction X parallel to the main surface” shown in FIGS. 3 and 4. Therefore, the second fin 113 is arranged so as to overlap with the arrangement position of the main body 226 of the semiconductor module 22 in the “direction X parallel to the main surface”. The finless portion 110 a is provided on both of the two heat sinks 11 that sandwich the semiconductor module 22.

  As shown in FIG. 4, leaf springs 13, which are examples of elastic members that bias the semiconductor module 22 from both sides via the heat sink 11 by elastic force, are attached to the finless portions 110 a on both sides. . The leaf spring 13 has a U-shaped cross-sectional shape, and a flat surface portion 13a facing the end surface in the thickness direction Y of the finless portion 110a (the top surface of the finless portion 110a in FIG. 4), and a flat portion A member formed by integrally forming a leg portion 13b extending at right angles to the flat surface portion 13a from both end sides of the 13a, and a curved portion 13c that bends at both end sides of the flat surface portion 13a so as to connect the flat surface portion 13a and the leg portion 13b. It is.

  The leaf spring 13 is inserted in the thickness direction Y of FIG. 4 so that the two heat sinks 11 arranged on both sides with the semiconductor module 22 interposed therebetween are fitted from the outside to the finless portion 110a on the leg portion 13b side. The flat portion 13a is attached by being deeply fitted until it comes into contact with or close to the top surface of the finless portion 110a. By this operation, the space between the opposing leg portions 13b formed shorter than the length of the fin projecting direction Z (direction perpendicular to the substrate portion 110) in the opposing finless portion 110a is pushed outward, so that the leaf spring 13 The elastic force acting inward to return to the original state gives a force that pushes the side surface of the opposed finless portion 110a inward to the heat sinks 11 on both sides as a clamping force.

  A total of four leaf springs 13 are attached to each of the upper end and the lower end of each semiconductor device 10. For this reason, the four leaf springs 13 hold the semiconductor module 22 in a balanced manner from the outside of the four corners of the rectangular main body 226 with an equal force. As a result, the main body portion 226 of the semiconductor module 22 and the insulating substrate 12 and the heat radiation grease on both sides thereof are strongly sandwiched and fixed in close contact by the main surfaces 111 of the two heat sinks 11, as shown in FIG. Two semiconductor devices 10 are formed.

  Since the semiconductor device 10 having the above configuration includes one semiconductor module 22, in the three-phase inverter circuit, as shown in FIG. 5, six semiconductor devices 10 are arranged adjacent to the inverter circuit unit 30 that is a power unit. Will be. FIG. 5 is a perspective view showing a state in which the six semiconductor devices 10 are stored in the case 38 of the inverter circuit unit 30. FIG. 5 shows a state in which the lid portion 37 attached to the upper portion of the lower case 31 is removed for easy understanding of the arrangement state of the semiconductor device 10. FIG. 7 is a cross-sectional view showing the positional relationship between the case 38 housing the semiconductor device 10 and the control substrate 101.

  The lower case 31 is a rectangular parallelepiped box having an open upper surface and two opposite side surfaces. A lid portion 37 is attached to the upper surface as shown in FIGS. 5 and 7, and a plate is provided on each of the two opposite side surfaces. The ventilating path forming members 32 and 33 are attached. The case 38 includes a lid portion 37, a lower case 31, and ventilation path forming members 32 and 33. Each of the ventilation path forming members 32 and 33 is formed with a plurality of ventilation openings 32b (four ventilation openings in this example) arranged in the lateral direction (corresponding to the fin protruding direction Z). The plurality of ventilation openings 32 b in the ventilation path forming member 32 are inlets on the upstream side of the air flow forcibly blown into the case 38 of the inverter circuit unit 30 by the fan 9. The ventilation port 32b is an outlet on the downstream side of the air flow.

  The ventilation path forming members 32 and 33 are fixed to the lower case 31 by being screwed by mounting screws 36 to female thread portions formed at four corners of each of the two side surfaces of the lower case 31. The lower case 31 and the ventilation path forming members 32 and 33 are resin members, respectively. The lid portion 37 is a metallic member made of, for example, aluminum die casting, copper, a copper alloy, or iron. Thereby, a part of the case 38 (the lid portion 37) is made of metal, and the remaining portion (the lower case 31 and the like) is made of a resin material.

  In the case in which the lower case 31 and the ventilation path forming members 32 and 33 are integrated, six semiconductor devices 10 are inserted and installed at predetermined positions from above. Two semiconductor devices 10 are arranged close to each other in a straight line, two in the vertical direction (corresponding to the direction X parallel to the main surface) and three in the horizontal direction (corresponding to the fin protruding direction Z). The semiconductor module 22 is electrically connected by wire so as to constitute the U-phase, V-phase, and W-phase in the horizontal direction and the upper arm and the lower arm of the same phase in the vertical direction. Therefore, since the six semiconductor devices 10 are closely and densely installed inside the case, collision and damage of each part due to vehicle vibration can be suppressed.

  Each semiconductor device 10 is mounted in the case 38 so that the control signal terminal 225 is on the upper side and the collector side electrode terminal 223 and the emitter side electrode terminal 224 are on the lower side. Therefore, in the case 38, the second fins 113 are positioned on both the upper and lower sides of the semiconductor device 10 so as to sandwich the first fins 112 arranged in the middle.

  As described above, each heat sink 11 includes an internal thread portion 114 in which a thread that penetrates in the thickness direction of at least one of the second fins 113 advances. The female screw portion 114 and the bolt 60 are means for screwing and fixing the lid portion 37 and the heat sink 11 which are part of the case for housing the semiconductor device 10. Each female thread portion 114 is provided on the heat sink 11 in order to fasten the lid portion 37 and the heat sink 11 together with the bolt 60 when the respective semiconductor devices 10 are accommodated in the case 38. The through-hole 373 formed in the lid portion 37 through which the bolt 60 is inserted and the female screw portion 114 are arranged in a positional relationship corresponding to each other.

  When six semiconductor devices 10 are housed in the case of the inverter circuit unit 30, each semiconductor device 10 is placed in the lower case 31 so that the upper and lower arms of the U phase, V phase, W phase, and each phase are appropriate. Temporarily arrange at a predetermined position. And the cover part 37 is covered on the upper surface of the lower case 31 so that each said through-hole 373 and the internal thread part 114 respond | correspond, the volt | bolt 60 is inserted in each through-hole 373, and all the volt | bolts 60 are tightened. Thereby, each semiconductor device 10 is arranged at a predetermined position with respect to the case 38 of the inverter circuit unit 30.

  The adjacent ventilation openings 32b are partitioned in the lateral direction (corresponding to the fin protruding direction Z) by the partition portions 32a formed in the ventilation path forming members 32 and 33. Each partition portion 32 a is provided so as to correspond to a portion where the first fin 112 of the heat sink 11 is not formed with respect to the semiconductor device 10 in the lower case 31. Accordingly, the four partition portions 32 a formed on each of the ventilation path forming members 32 and 33 face portions including both sides of the main body portion 226 and both sides of the substrate portion 110 in the semiconductor device 10.

  Thereby, about each heat sink 11, the side part of the 1st fin 112 located in the edge part of the direction X parallel to a main surface is formed in the four ventilation openings 32b formed in the ventilation path formation members 32 and 33, respectively. It corresponds. The ventilation openings 32b formed in the ventilation path forming members 32, 33 on the two side surfaces located at the opposite sides communicate with each other in the direction X parallel to the main surface via the first fins 112 arranged therebetween. That is, with respect to the semiconductor device 10 on the upstream side and the downstream side of the air flow, the plurality of first fins 112 arranged in the thickness direction Y are aligned in the thickness direction Y so as to be aligned with the direction X parallel to the main surface. They are aligned. Thereby, each gap formed between the first fins 112 arranged in the thickness direction Y is connected in the semiconductor device 10 on the upstream side and the upstream side of the air flow, and linearly extends in the direction X parallel to the main surface. It has come to be connected. Due to the gaps between the first fins 112 connected in this way, the ventilation openings 32b formed in the ventilation path forming members 32, 33 on the two side surfaces communicate with each other, and the ventilation openings 32b located on the two side faces. Will be formed.

  When forced air is supplied to the inverter device 1 by the fan 9, air flows in from the vent 32 b located on the upstream side of the air flow, and then flows through the gaps between the first fins 112. The air is discharged to the outside through the vent 32b located on the downstream side of the air flow. Therefore, the direction in which the forced air flows through the inverter circuit unit 30 coincides with the direction X parallel to the main surface. During operation of the inverter circuit unit 30 composed of the six semiconductor modules 22, the heat generated in each semiconductor element is generated by the insulating substrate 12, the heat radiation grease on both sides, the substrate portion 110, the first fin 112, or the second When the forced air flows through the fins 113 and flows through the gaps between the first fins 112, the forced air is discharged from both sides of the semiconductor module 22 and the semiconductor modules 22 are cooled.

  FIG. 6 is a perspective view showing the appearance of the inverter device 1. As shown in FIG. 6, the inverter device 1 that drives and controls the motor 3 is a device in which a capacitor unit 50, an inverter circuit unit 30, and a control circuit unit 40 are stacked and integrated in three stages. The capacitor unit 50 has a capacitor 5 and a capacitor 6 mounted inside a case 51. The control circuit unit 40 has a control board 101 constituting the control circuit 100 mounted inside the case 41.

  Mounting legs 35 having internal thread portions for mounting the inverter circuit unit 30 to the case 51 of the capacitor unit 50 installed below are provided at four corners at the bottom of the lower case 31. The capacitor unit 50 is integrally attached to the lower side of the inverter circuit unit 30 by screwing and fixing the case 51 to each attachment leg 35 with each attachment screw 53.

  As shown in FIG. 5, female screw portions 34 for attaching a lid portion 37 to the lower case 31 are formed at four corners of the upper portion of the lower case 31. A through hole 372 is formed in the lid portion 37 at a position corresponding to the female screw portion 34 formed in the lower case 31. At four corners of the lid portion 37, there are provided mounting legs 371 having female screw portions for attaching the case 41 of the control circuit unit 40 installed above to the case 38 of the inverter circuit unit 30.

  Further, the lid portion 37 is provided with four ground connection portions 374 that protrude outward from the lower case 31. Each ground connection portion 374 is formed with a female screw portion 375 passing therethrough. Each ground connection portion 374 protrudes in a direction perpendicular to the air blowing direction by the fan 9 and is disposed outside the air blowing passage.

  When the case 38 of the inverter circuit unit 30 is grounded to the vehicle-side ground, the vehicle-side member corresponding to the vehicle-side ground and at least one ground connection portion 374 are screwed together by screwing the bolt 61 and the female screw portion 375. ,Connecting. As a result, the vehicle-side ground and each heat sink 11 are electrically connected via the metal lid portion 37 and the ground connection portion 374. At this time, all the heat sinks 11 accommodated in the case 38 have the same electric potential by fastening the lid portion 37 and the respective heat sinks 11 with the bolts 60. Furthermore, since the two heat sinks 11 sandwiching each semiconductor module 22 from both sides are sandwiched and integrated by the leaf spring 13 in the case of being made of metal, they have the same potential.

  Further, when the case 38 is grounded to the vehicle-side ground by another method, a vehicle-side member corresponding to the vehicle-side ground is connected to a ground wire (wired), and a terminal provided at the tip of the ground wire (wired) Is screwed to the female thread portion 375 of at least one ground connection portion 374 with a bolt 61. As a result, the vehicle-side ground and each heat sink 11 are electrically connected via the metal lid portion 37 and the ground wire.

  Thus, the lid portion 37 is arranged in contact with the heat sink 11 and holds each semiconductor device 10. Unlike the other lower case 31 and the ventilation path forming members 32 and 33 that constitute the case 38, the lid portion 37 is formed of a metal instead of a resin material, so that the lid portion 37 is electrically connected to the heat sink 11 in contact therewith. It is in. As a result, in the unlikely event that the current of the semiconductor module 22 flows through the heat sink 11 and enters a high voltage state, the vehicle-side ground and the heat sink 11 are energized by the above ground connection. It is possible to detect the leakage current to the heat sink 11 by, for example. Therefore, it is possible to take a configuration capable of detecting the occurrence of the leakage current, and to ensure electrical safety.

  The control circuit unit 40 fixes the control board 101 of the control circuit unit 40 to the lid portion 37 (a part of the case 38) of the inverter circuit unit 30 by screwing or the like, and then attaches the case 41 covered from above to each mounting screw. By fixing the screws to the mounting legs 341 by 44, the inverter legs are integrally attached above the inverter circuit unit 30.

  Further, from the case 38 of the inverter circuit unit 30, a three-phase terminal portion 52 for connecting an output line to be output to the motor 3 is exposed, and a terminal portion for connecting a power input line from the battery 4 ( (Not shown) is exposed. In addition, the case 41 of the control circuit unit 40 exposes a connector portion 43 for connecting a power supply line for turning on the vehicle-side power to the control circuit 100 and a signal line from the vehicle ECU, and the capacitor unit 50 and the inverter. A lead wire passage 42 for drawing a lead wire from the circuit unit 30 into the control circuit unit 40 is provided. The case 41 and the case 51 are resin members, respectively.

  Since the lower case 31 and the like are formed of a resin material and have no electromagnetic shielding properties, there is a concern that noise from the high power switching element included in the semiconductor module 22 is transmitted to the outside. Therefore, since the lid portion 37 is made of metal among the members constituting the case 38, it has electromagnetic shielding properties and can exhibit a noise blocking function. Since the lid portion 37 is disposed so as to face the control substrate 101 constituting the control circuit 100, the lid 37 blocks a noise propagation path from each semiconductor device 10 to the control substrate 101. Further, the lid portion 37 has a function as a heat shield that blocks heat released from each heat sink 11 from being transmitted to the control board 101 side, and reduces the temperature rise of each electronic component on the control board 101. Work.

  Furthermore, it is preferable to apply a silicon-based heat radiation grease having good thermal conductivity between the lid portion 37 and each heat sink 11. Due to the presence of the heat radiation grease, the heat released from each heat sink 11 can be conducted to the side of the ground connection portion 374 projecting outward through the lid portion 37.

  Next, the function of the second fin 113 will be described in detail. FIG. 7 is a cross-sectional view showing a state in which the semiconductor device 10 is housed in the case 38 of the inverter circuit unit 30. When the six semiconductor devices 10 are mounted in the case 38 of the inverter circuit unit 30, the lid portion 37 is fixed to the lower case 31 by screwing or the like. Therefore, as shown in FIG. In the upper part, external force is applied downward from the lid part 37, while the lower part of each heat sink 11 presses the bottom part of the lower case 31, so that it receives a reaction force directed upward from the bottom part. That is, all the heat sinks 11 of the six semiconductor devices 10 are pressed from the case 38 of the inverter circuit unit 30 inward (thickness direction Y).

  For this reason, an excessive load may be applied to both upper and lower end portions that receive external force directly from the lid portion 37 (a part of the case 38) in each heat sink 11, and fin deformation occurs during the assembly process. Sometimes. In the semiconductor device 10 of the present embodiment, the second fins 113 located at the upper and lower ends of the heat sink 11 are thicker than the first fins 112, so that the strength of the second fins 113 can be improved. . Therefore, the semiconductor device 10 includes a fin portion that is not easily deformed by a direct external force from the case 38.

  Further, when the semiconductor element generates heat, the generated heat is first transmitted to the substrate portion 110 via the insulating substrate 12 and the like, and then to the first fin 112 and the second fin 113 formed integrally with the substrate portion 110. It is transmitted. In particular, the second fin 113 has a larger heat capacity than the first fin 112 because it has a large thickness and a large volume per length. Therefore, the second fin 113 has an excellent ability to store heat temporarily, and greatly functions as a heat mass in the heat sink 11.

  In the semiconductor device 10, when the semiconductor element generates heat during operation of the inverter circuit unit 30, the heat is transmitted to the board portions 110 on both sides and then to the first fin 112 and the second fin 113. At this time, since the second fin 113 having the thick part has a high heat storage capacity, the heat transmitted to the substrate unit 110 easily moves to the second fin 113, and the heat in the substrate unit 110 is moved outward. It becomes easy to escape. For this reason, when the semiconductor element generates heat in a short time, the heat is rapidly released from the substrate part 110, and the further heat generation of the semiconductor element moves to the substrate part 110, causing a rapid temperature change of the semiconductor element. And temperature rise is suppressed.

  Therefore, the response speed of the temperature change of the semiconductor element becomes dull, the transient characteristics of the semiconductor device 10 are improved, and it is possible to suppress an excessive heat load on the semiconductor element. When the forced air from the fan 9 is supplied, heat is removed from the first fin 112 or the second fin 113 on both sides of the semiconductor module 22, and the first fin 112 from the second fin 113. As a result, a space is generated in the heat storage capacity of the second fin 113 due to the promotion of the heat transfer to the air and the heat transfer from the second fin 113 to the air. Can be improved.

  Below, the effect which the power unit of this embodiment brings is described. The inverter circuit unit 30 includes a semiconductor module 22 incorporating a semiconductor element, and a metal heat sink 11 provided integrally with the semiconductor module 22 and dissipating heat from the semiconductor module 22 into the air. A device 10 and a case 38 for housing a plurality of semiconductor devices 10 so as to be integrated are provided. The case 38 is partially made of metal and the remainder is made of a resin material. The plurality of semiconductor devices 10 are accommodated in the case 38 in a state in which a part of the case 38 (for example, the lid portion 37) made of metal is in contact with the heat sink 11. A part of the case 38 formed of the metal is electrically connected to a member on the vehicle side.

  According to the above configuration, a part of the case 38 made of metal is brought into contact with the heat sink 11 and electrically connected to the vehicle side member, thereby complicated ground connection between the heat sink 11 and the vehicle side member. This electrical connection makes it possible to detect a current leaked to the heat sink 11 for some reason. Furthermore, the propagation of noise from each semiconductor device 10 can be suppressed by a part of the metal case 38, which adversely affects various electronic components (control circuit 100, capacitors 5, 6 and the like) used to demonstrate the function of the power unit. Noise resistance that is not given can be obtained. Therefore, the various electronic components can be protected, and a power unit can be provided that achieves both high voltage detection of the air-cooling heat sink 11 and ensuring noise resistance.

  A part of the case 38 made of metal is a lid portion 37 that covers one surface of the case, and the lid portion 37 faces the control substrate 101 that constitutes the control circuit 100 that controls the operation of the semiconductor element. It is arranged in. According to this configuration, it is possible to suppress the noise from each semiconductor device 10 from propagating to the control substrate 101 by the metal lid portion 37, malfunction of electronic components for controlling the semiconductor device 10, and EMC characteristics. It is possible to suppress deterioration and the like. Further, the heat generated by each heat sink 11 can be prevented from being transferred to the control board 101 by the metal lid portion 37, so that deterioration of the electronic component can be reduced and the life can be ensured.

  Further, a part of the case formed of metal is a lid portion 37 that covers one surface of the case, and the lid portion 37 and the heat sink 11 are fastened by screwing means (bolt 60, through hole 373, and female thread portion 114). . According to this configuration, by providing the fastening force by the screwing means, the adhesion between the heat sink 11 and the lid portion 37 is improved, and a conductive path and a heat transfer path from the heat sink 11 to the lid portion 37 are reliably formed. Can do. As a result, a power unit can be obtained that reliably constructs the detection of the high voltage of the air-cooling heat sink and the securing of noise resistance.

  Further, the second fin 113 exhibits strength against the force that the thick portion receives from the inner surface of the lid portion 37. For this reason, in the thickness direction Y, it has a function of protecting the first fin 112 in strength, suppresses deformation, and the second fin 113 itself is not easily deformed. It is kept well. Thus, if the adhesiveness of the 2nd fin 113 and the cover part 37 can be ensured, the above-mentioned leakage current detection will be performed reliably and the function can be exhibited long.

  Further, if the deformation of the first fins 112 can be suppressed, the air passages that are the gaps formed between the first fins 112 are maintained at a predetermined size. For this reason, there is no portion where the cooling air is difficult to flow because the ventilation resistance increases, and each semiconductor device 10 can exhibit a desired cooling performance, and the life of the semiconductor device 10 can be extended. In addition, if the deformation of the first fin 112 can be suppressed in this way, it is difficult for assembly problems to occur when the semiconductor device 10 is housed in the case 38 of the inverter circuit unit 30, which contributes to an improvement in productivity.

  Further, the second fin 113 also exhibits strength against the force that the thick portion receives from the inner surface of the lower case 31 with respect to the load applied from the lower case 31 and the adjacent semiconductor device 10 in the fin protruding direction Z. Moreover, since the adjacent thick portions are in contact with each other, the strength is exhibited. For this reason, in both the thickness direction Y and the fin protruding direction Z, it has a function of protecting the first fin 112 in strength and suppresses deformation. When the deformation of the first fins 112 can be suppressed in this way, the air passages that are the gaps formed between the first fins 112 are maintained at a predetermined size. For this reason, there is no portion where the cooling air is difficult to flow because the ventilation resistance increases, and each semiconductor device 10 can exhibit a desired cooling performance, and the life of the semiconductor device 10 can be extended. In addition, if the deformation of the first fin 112 can be suppressed in this way, it is difficult for assembly problems to occur when the semiconductor device 10 is housed in the case 38 of the inverter circuit unit 30, which contributes to an improvement in productivity.

  In addition, the heat sink 11 includes a plurality of first fins that protrude from the substrate portion 110 so as to form a row at intervals in the thickness direction Y of the substrate portion 110 that is thermally coupled to the semiconductor module 22. 112 and a second fin 113 projecting from the substrate portion 110 on the outer side further than the first fin 112 located on the outermost side in the thickness direction Y. The second fin 113 has a thick part having a thickness dimension larger than that of the first fin 112. The thick part of the second fin 113 and the lid part 37 are fastened by screwing means.

  According to this configuration, by using the thickened portion of the second fin 113 to configure the screwing means, it is easy to form a shape that can exhibit the function of fixing and closely contacting the heat sink 11 and the lid portion 37. Furthermore, when forming the female threaded portion 114 of the screwing means in the thick portion of the second fin 113, it is easy to secure the required number of threads, etc., and other parts and components for screw tightening Even if it is not required separately, a structure capable of exerting a screw tightening function can be secured, and a considerable number of screw threads can be formed, so that the fastening force can be improved.

  Each semiconductor device 10 includes two heat sinks 11 that sandwich the semiconductor module 22 from both sides, and a leaf spring 13 that biases the force that sandwiches the semiconductor module 22 by elastic force. The two heat sinks 11 are sandwiched by the leaf springs 13 so as to approach each other. According to this configuration, since the two heat sinks 11 are held together by sandwiching the two heat sinks 11 sandwiching the semiconductor module 22 from both sides by the leaf springs 13, the lid portion 37 and each heat sink 11 are connected to each other. It is possible to provide a reduction in the number of screwing means for fastening and simplification of the configuration. Moreover, it can contribute to the improvement of the adhesiveness between the lid portion 37 and each heat sink 11.

  The member on the vehicle side is connected to a portion of the lid portion 37 that protrudes from the air blowing passage in a direction orthogonal to the air blowing direction by the fan 9. According to this configuration, the part that is electrically connected to the vehicle-side member is set to a part that does not interfere with the duct or the like that forms the air passage. Thereby, the connection of the member on the vehicle side and the lid portion 37 can be performed in a state where the duct or the like does not get in the way. Therefore, the workability related to the connection can be improved.

  Furthermore, according to the semiconductor device 10, the heat sink 11 has a double-sided cooling structure that can receive heat from both main surfaces of the semiconductor module 22, so that it is excellent in combination with the improvement of the transient characteristics due to the thick part of the second fin 113. Exhibits excellent heat dissipation performance.

  In the semiconductor device 10, the second fin 113 is smaller in length than the first fin 112 in the direction X perpendicular to the thickness direction Y and parallel to the main surface of the semiconductor module. A leaf spring 13 (elastic member) that urges the finless portion 110a where the second fin 113 does not protrude in the substrate portion 110 of the heat sink 11 on both sides of the semiconductor module 22 with elastic force. Is provided.

  According to this configuration, the second fin 113 has a shorter length in the direction parallel to the main surfaces 221 and 222 of the semiconductor module 22 than the first fin 112. It is possible to construct a space in which the fin 113 does not protrude. Further, since the leaf spring 13 for biasing the force for sandwiching the semiconductor module 22 is provided in the space, the fin strength and the heat mass function are improved, and the mountability for effectively arranging the thermal bonding means between the semiconductor module 22 and the heat sink 11 is provided. Can be realized at the same time.

  Further, when silicon-based heat radiation grease having good thermal conductivity is applied between the metal (for example, aluminum die-cast) lid portion 37 and each heat sink 11, it is discharged from each heat sink 11 due to the presence of heat radiation grease. The conducted heat can be transferred to the ground connection part 374 side protruding outward through the lid part 37. According to this, since the heat dissipation performance to the outside of the power unit is improved, the heat sink 11 can be reduced in size, and thus the inverter circuit unit 30 can be reduced in size.

  In each semiconductor device 10, the thick portion of the second fin 113 includes a cover portion 37 that is a part of a case for housing the semiconductor device 10 and a female screw portion 114 for screwing and fixing. According to this configuration, the bolt 60 is screwed into the female screw portion 114 and the heat sink 11 is screwed to the housing case 38, so that when the semiconductor device 10 is housed in the case 38, The positional relationship is uniquely determined, the proper positioning setting of the semiconductor device 10 with respect to the case 38 becomes possible, and rattling between the lid portion 37 and each heat sink 11 can be prevented. Furthermore, since the female screw portion 114 requires a predetermined number of threads or the like, other parts and components for screw tightening are used in order to utilize the thick portion of the second fin 113 for forming the female screw portion 114. Even if it is not necessary, it is possible to form a female screw portion that can exhibit a screw tightening function.

  The metal lid portion 37 is provided with mounting legs 371 having a female screw portion for mounting the case 41 of the control circuit unit 40 installed above to the inverter circuit unit 30. Accordingly, since the female screw portion is formed in the metal lid portion 37, for example, insert molding of the screw portion can be arranged as compared with the case where the female screw portion is formed in the resin material portion of the case 38. , Expenses can be reduced.

(Other embodiments)
The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

  The structure of the said embodiment is an illustration to the last, Comprising: The scope of the present invention is not limited to the range of these description. The scope of the present invention is indicated by the description of the scope of claims, and further includes meanings equivalent to the description of the scope of claims and all modifications within the scope.

  In the above embodiment, the lid portion 37 is fastened to each heat sink 11 by a plurality of bolts 60. However, when the adhesion between the lid portion 37 and the second fin 113 of each heat sink 11 is ensured. The fastening by the bolt 60 can also be omitted.

  In the above embodiment, a high output IGBT is formed as a semiconductor chip, but a semiconductor chip in which a low output MOSFET, JFET, or the like is formed may be used.

  The use of the motor driven by the inverter device of the above embodiment is not limited to vehicle travel, but includes power generation, engine starting, driving of auxiliary equipment such as a compressor, and the like. Or an inverter device loaded in a plurality of stages may be provided.

DESCRIPTION OF SYMBOLS 1 ... Inverter apparatus 10 ... Semiconductor device 11 ... Heat sink 13 ... Leaf spring (elastic member)
20a to 20f ... IGBT (semiconductor element)
21a-21f ... Free wheeling diode (semiconductor element)
22, 22a-22f ... Semiconductor module 30 ... Inverter circuit unit (power unit)
31 ... Lower case (the rest of the case)
37 ... Lid (part of the case)
60 ... Bolt (screwing means)
DESCRIPTION OF SYMBOLS 100 ... Control circuit 101 ... Control board 110 ... Board | substrate part 112 ... 1st fin 113 ... 2nd fin 114 ... Female thread part (screwing means)

Claims (6)

A semiconductor device comprising a semiconductor module containing a semiconductor element, and a metal heat sink provided integrally with the semiconductor module and dissipating heat of the semiconductor module into the air;
A case for accommodating a plurality of the semiconductor devices so as to be integrated;
With
The case is partially formed of metal and the rest is formed of a resin material,
The plurality of semiconductor devices are accommodated in the case in a state where a part of the case formed of the metal is in contact with the heat sink,
A part of the case made of the metal is electrically connected to a member on the vehicle side. A part of the case formed of the metal is a lid that covers one surface of the case,
The power unit according to claim 1, wherein the lid and the heat sink are fastened by screwing means. The heat sink is
A substrate portion thermally coupled to the semiconductor module;
A plurality of first fins each protruding from the substrate portion so as to form a row at intervals in the thickness direction;
A fin that protrudes from the substrate portion on the outer side further than the first fin located on the outermost side in the thickness direction, and has a thick portion with a thickness dimension larger than that of the first fin. When,
With
The power unit according to claim 2, wherein the thick portion and the lid portion of the second fin are fastened by the screwing means. The semiconductor device includes two heat sinks that sandwich the semiconductor module from both sides, and an elastic member that urges a force that sandwiches the semiconductor module by elastic force,
The power unit according to any one of claims 1 to 3, wherein the two heat sinks are sandwiched by the elastic member so as to approach each other. Blower means for blowing air to the heat sink,
The vehicle-side member is connected to a portion protruding from the air blowing passage in a direction orthogonal to the air blowing direction by the blowing means in a part of the case formed of the metal. The power unit according to any one of claims 1 to 4, wherein the power unit is characterized. A part of the case formed of the metal is a lid that covers one surface of the case,
The power unit according to any one of claims 1 to 5, wherein the lid portion is arranged to face a control board constituting a control circuit that controls the operation of the semiconductor element. .

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