JP2005123265A - Power device cooling apparatus and inverter unit for motor driving - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide technique which can cool a power device efficiently. <P>SOLUTION: A power device 101 is connected to a conductive member 110, and connected to other electric elements through the conductive member 110. Cooling mechanism such as heat pipe structure is incorporated in the conductive member 110. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a technique applied to, for example, an inverter unit for a hybrid vehicle whose pressure is increasing.

  In recent years, power devices such as transistors have been increased in pressure and frequency. As the current increases, the generation of heat from the conductor and the semiconductor chip increases. As the frequency increases, switching loss in the transistor increases, and heat is generated due to the loss.

  Conventionally, a configuration in which a case of a power module incorporating a power device is cooled by a water cooling jacket incorporating a heat sink or a cooling pipe has been adopted.

  However, as described above, the configuration in which the case of the power module is cooled has a problem that efficient cooling cannot be performed.

  That is, in the configuration in which the module case is cooled, there is a relatively large thermal resistance between the power module that is the main heat generation source and the case that is the direct cooling target. For this reason, efficient heat exchange cannot be performed between the case where heat from the power module is transmitted and the refrigerant in the heat exchange part such as a heat sink or a water cooling jacket.

  In order to perform sufficient heat exchange, it is necessary to cover by increasing the contact area between the heat cooling mechanism and the case, or increasing the heat radiation area of the heat sink. However, such countermeasures increase the size of the cooling mechanism.

  On the other hand, further miniaturization and weight reduction are required for inverters and power distributor units (PDU) for automobiles. Increasing the size of the cooling mechanism is contrary to this requirement.

  Accordingly, an object of the present invention is to provide a technique capable of efficiently cooling a power device.

  In order to solve the above-mentioned problem, the invention according to claim 1 is to connect a power device having an element main body and a connector, and the connector to electrically connect the power device to another electric element. A conductive member, and the conductive member has a cooling structure.

  According to a second aspect of the present invention, as the cooling structure, the conductive member encloses a liquid in an enclosed space formed therein, and performs cooling by utilizing vaporization and vaporization of the liquid in the enclosed space. It has a heat pipe structure or a structure that cools by flowing a refrigerant in a flow path formed inside.

  A third aspect of the invention is an inverter unit for driving a motor incorporating the power device cooling device according to the first or second aspect.

  According to a fourth aspect of the present invention, a circuit for driving a motor and a power feeding terminal that is directly connected to a power receiving terminal on the motor side and flows a driving current to the motor are integrated in a single form. This is an inverter unit for driving a motor incorporated in the case.

  The invention according to claim 5 is the inverter unit for driving the motor according to claim 4, wherein the power device used in the circuit for driving the motor and the conductive member connected thereto are provided in claim 1 or claim The power device cooling apparatus described in 2 is applied.

  According to the power device cooling apparatus of the first aspect of the present invention, since the connector of the power device is connected to the conductive member having the cooling structure, the power device can be efficiently cooled.

  Further, according to the invention described in claim 2, since the conductive member is cooled by the refrigerant flowing through the heat pipe structure or the internal flow path, more efficient cooling can be performed.

  Furthermore, according to the invention of claim 3, the power device of the inverter unit for driving the motor can be efficiently cooled.

  According to the inverter unit for driving a motor according to claim 4, the circuit for driving the motor and the power supply terminal that is directly connected to the power receiving terminal on the motor side and flows the driving current to the motor are integrated. Since it is incorporated in the case in a simplified form, it is possible to omit external wiring for connecting the drive circuit and the motor, and to easily connect them.

  According to the fifth aspect of the invention, there is an advantage that the configuration for cooling the motor itself and the configuration for cooling according to the power device cooling apparatus can be easily shared.

{Basic principles of the invention}
For example, in a car inverter or a power distribution unit (PDU), a semiconductor bare chip is directly attached to a conductive wire (including a bus bar) for miniaturization. Here, considering that it is a semiconductor chip or a conductive wire that generates heat due to high pressure, efficient cooling is possible by directly cooling the conductive wire.

  The present invention is based on such an idea.

{First embodiment}
The power device cooling apparatus according to the first embodiment of the present invention will be described below.

  FIG. 1 is a perspective view showing a power device cooling apparatus. This power device cooling apparatus includes a power device 101 and a conductive member 110.

  The power device 101 is a semiconductor element such as a high-power switching element or a diode used in a circuit (for example, an inverter circuit) for driving a load such as a motor, a power supply circuit, a power distribution circuit, or the like. Here, description will be made assuming that the power device 101 is a power MOSFET.

  The power device 101 is a bare chip, and includes a device body 102 formed in a chip shape that is a flat bowl shape, and a gate electrode, a source electrode, and a drain electrode as connectors that are exposed on the surface of the device body 102. (In FIG. 1, only the gate electrode 102a is shown). More specifically, the gate electrode 102a and the source electrode are exposed on one side (the upper surface side in FIG. 1) of the element body 102, and the drain electrode is disposed on the other surface (the lower surface side in FIG. 1) of the element body 102. Is exposed. Note that the power device 101 is not necessarily a bare chip, and may be one in which an element body is sealed with a resin or the like, and an electrode is drawn to the outside via a lead terminal.

  The conductive member 110 is a bus bar-shaped member formed of a conductive material such as metal, and is formed in a long shape. More specifically, the conductive member 110 includes a long plate-like base body 112 having a predetermined thickness, and a flat plate-like heat dissipation formed on one end side of the base body 112 so as to spread in the width direction of the base body 112. Part 114.

  An encapsulating space 113 extending along the longitudinal direction of the base body 112 is formed in the conductive member 110. A proper amount of liquid is enclosed in the enclosed space 113, and a kind of heat pipe structure is formed in which cooling is performed by using vaporization and vaporization of the liquid in the enclosed space 113.

  The enclosed space 113 may be a substantially rectangular parallelepiped space extending from the base body 112 to the heat radiating portion 114 with substantially the same cross-sectional area shape, and the outer peripheral shape of the heat radiating portion 114 in the heat radiating portion 114 portion. It may have a spatial shape that expands following the above.

  The gate electrode of the power device 101 is connected to one surface of the base 112 of the conductive member 110 by soldering or the like. In order to connect the chip-shaped power device 101, the base body 112 preferably has a portion extending in a planar shape. For example, the base 112 is preferably formed in a flat cross-sectional shape or the like.

  The conductive member 110 is also connected to other electrical components connected to the gate electrode. For example, the other end of the conductive member 110 is connected to another electrical component. As a result, the conductive member 110 constitutes part of the wiring, and the gate electrode of the power device 101 is electrically connected to the other electrical component via the conductive member 110. For example, power is input or output through the conductive member 110. Note that the gate electrode 102a and the source electrode of the power device 101 are appropriately connected to other electrical components through lead wires, bus bars, and the like.

  A portion of the conductive member 110 to which the gate electrode of the power device 101 is connected receives heat from the power device 101, and thus functions as a heat radiating portion in the heat pipe structure.

  Moreover, the said heat radiating part 114 is arrange | positioned in the part etc. which touch outside air in the refrigerant | coolant atmosphere from the outside, etc., and functions as a cooling part in a heat pipe structure. The heat radiating portion 114 is formed in a plate shape wider than the base 112 in order to increase the heat radiating area as much as possible. You may form in the shape for enlarging a thermal radiation area by forming a thermal radiation fin in this thermal radiation part 114, or forming in a spiral shape.

  In this power device cooling apparatus, when a current flows through the power device 101 and the power device 101 generates heat, the heat is directly transmitted from the gate electrode to the conductive member 110. As a result, the liquid in the enclosed space 113 is vaporized at the portion where the power device 101 is connected, flows into the heat radiating portion 114, and radiates and liquefies at the heat radiating portion 114. This liquid returns to the part to which the power device 101 is connected due to a capillary phenomenon or the like. By repeating this, the power device 101 is cooled.

  According to the power device cooling apparatus configured as described above, since the drain electrode of the power device 101 is connected to the conductive member 110 having a cooling structure, heat conduction from the power device 101 to the conductive member 110 is efficient. The power device 101 can be efficiently cooled.

  In addition, although this embodiment demonstrated the example in which the electrically-conductive member 110 employ | adopted a kind of heat pipe structure, you may provide the other cooling structure. For example, a configuration may be employed in which a flow path is formed in the conductive member, and cooling is performed by flowing a coolant such as water, oil, air, or alternative chlorofluorocarbon in the flow path. Further, the conductive member 110 may be formed with a shape for increasing the heat radiation area such as a plurality of heat radiation fins.

  However, efficient cooling is achieved by applying a configuration in which the conductive member 110 is cooled by flowing a coolant such as water, oil, air, or alternative chlorofluorocarbon in a heat pipe structure or a flow path formed in the heat pipe structure. It can be performed. In particular, by applying a heat pipe structure, it is possible to achieve cooling with a relatively simple configuration without requiring a mechanism for flowing a refrigerant.

  Such a power device cooling apparatus can be applied to various power supply units, power distribution units (such as PDUs), and the like in addition to the motor drive inverter unit described in the following embodiments.

{Second Embodiment}
A motor drive inverter unit incorporating a power device cooling apparatus according to a second embodiment of the present invention will be described. Here, an example applied to an inverter mounted on a hybrid car will be described.

  FIG. 2 is a block diagram showing an electrical configuration of a power system in the hybrid car. As shown in the figure, the inverter 11 is applied as an inverter device that drives a motor (engine motor) 12 for traveling of the hybrid car 13.

  2, reference numeral 14 denotes a tire, reference numeral 15 denotes a gasoline engine, reference numeral 16 denotes a generator, reference numeral 17 denotes a battery, reference numeral 18 denotes a high voltage relay, and reference numeral 19 denotes a boost converter.

  FIG. 3 shows an electric circuit diagram of the inverter 11.

  The inverter 11 is a three-phase inverter that drives a motor 12 that is a three-phase AC motor for vehicle travel, and is, for example, N as a high-arm side switching element in each of the U-phase, V-phase, and W-phase of the motor 12. For example, N-channel power MOSFETs 4a, 4b, and 4c are provided as low-arm side switching elements in the respective phases.

  The drains of the high arm side switching elements 3a, 3b, 3c are connected together to the power supply + side (P), and the sources thereof are connected to the drains of the low arm side switching elements 4a, 4b, 4c of the same phase. The sources of the low arm side switching elements 4a, 4b, 4c are all connected to the power supply side (N). Furthermore, each of the switching elements 3a, 3b, 3c, 4a, 4b, and 4c has free wheel diodes 5a, 5b, 5c, 6a, 6b, and 6c that flow current in the direction opposite to the direction in which the current flows. Connected in parallel. The connection points between the sources of the high arm side switching elements 3a, 3b and 3c and the drains of the low arm side switching elements 4a, 4b and 4c are the respective phases (9a to 9) of the U phase, V phase and W phase of the motor 2. 9b).

  Here, reference numerals 7a, 7b, 7c, 8a, 8b, and 8c in FIG. 3 indicate gate terminals that are control input terminals of the respective switching elements 3a, 3b, 3c, 4a, 4b, and 4c. Each switching element 3a, 3b, 3c, 4a, 4b, 4c is turned on and off at a timing according to a command signal given to the gate terminals 7a, 7b, 7c, 8a, 8b, 8c from the control unit.

  Each switching element 3a, 3b, 3c, 4a, 4b, 4c is not limited to the power MOSFET as shown in FIG. 3 as long as it is used in a general inverter, but is not limited to a power junction transistor or IGBT, JFET. In addition, other switching elements such as wide band gap devices capable of operating at high temperatures such as SiC, GaN, and C may be used.

  FIG. 4 is a partially broken perspective view showing the entire configuration of the inverter unit 20 incorporating the inverter 11 and the power device cooling device.

  The inverter unit 20 includes a case body 22 in which conductive members 30A and 30B and a plurality of switching elements 3a, 3b, 3c, 4a, 4b, and 4c are incorporated.

  The case body 22 is formed in a substantially bowl-shaped body, and the inside thereof is partitioned into a first space 24 and a second space 25 by a partition wall 23. Among them, in the first space 24, the switching elements 3a, 3b, 3c, 4a, 4b, 4c and the like are accommodated to form a predetermined inverter circuit. The second space 25 is a cooling space into which a refrigerant is introduced.

  The conductive members 30A and 30B include bases 32A and 32B and heat radiation portions 34A and 34B. The base bodies 32A and 32B are formed in an elongated plate shape, and the heat radiation portions 34A and 34B are wider than the base bodies 32A and 32B and have a shape wound in a spiral shape. A sealed space (not shown) extending along the longitudinal direction of the base bodies 32A and 32B is formed from the base bodies 32A and 32B to the heat radiation portions 34A and 34B in the same manner as the conductive member 110 in the first embodiment. The liquid is appropriately sealed in the sealed space. The conductive members 30A and 30B, like the conductive member 110, cool the bases 32A and 32B by a kind of heat pipe structure in which the bases 32A and 32B are heating sections and the heat radiating sections 34A and 34B are cooling sections. It is the composition to do.

  Each of the switching elements 3a, 3b, 3c, 4a, 4b, and 4c has the same configuration as that of the power device 101 in the first embodiment. The high arm side switching elements 3a, 3b, 3c are mounted and fixed to the conductive member 30A on one side in the same manner as described in the first embodiment, and the low arm side switching elements 4a, 4b, 4c are respectively fixed. Are mounted and fixed to the conductive member 30B on the other side in the same manner as described in the first embodiment except that the source electrode and the drain electrode are reversed.

  Each of the conductive members 30A and 30B penetrates the partition wall 23 and is disposed so as to hang the respective base portions 32A and 32B into the first space 24, and each of the heat radiating portions 34A and 34B is provided in the first space 24. It is fixed in the case body 22 so as to be disposed in the two spaces 25.

  Further, the source electrodes of the high arm side switching elements 3 a, 3 b, 3 c and the drain electrodes of the low arm side switching elements 4 a, 4 b, 4 c are respectively connected via busbar members 35. Each bus bar member 35 is formed with power supply terminals 35 a, 35 b, and 35 c extending toward the bottom surface side of the case body 22. Each of the power supply terminals 35a, 35b, and 35c protrudes outward from the bottom surface side of the case body 22, and can be connected to a power reception terminal on the motor 12 side.

  In addition, each of the conductive members 30A and 30B is connected to a +/− power cable 40 drawn to the outside, and is connected to an external power source via the power cable 40.

  Further, the case body 22 is provided with a connector portion 26 for inputting a gate signal, an introduction pipe 27 for introducing the refrigerant, and a discharge pipe 28 for discharging the refrigerant.

  The terminal of the connector part 26 is connected to the gate electrode of each switching element 3a, 3b, 3c, 4a, 4b, 4c in the case body 22 through a lead wire. A command signal from an external gate drive circuit is supplied from the connector portion 26 to each switching element 3a, 3b, 3c, 4a, 4b, 4c via a lead wire.

  The introduction pipe 27 and the discharge pipe 28 communicate with the second space 25, respectively. The introduction pipe 27 is connected to a supply source of refrigerant such as water, oil, air, and alternative chlorofluorocarbon via a supply pipe (not shown), and the discharge pipe 28 is connected to the discharge pipe. Then, the refrigerant from the refrigerant supply source is introduced into the second space 25 through the introduction pipe 27. The refrigerant introduced into the second space 25 takes heat from the heat radiating portions 34A and 34B and is then discharged from the discharge pipe 28. Note that the refrigerant may circulate through a cooling mechanism (not shown), or may introduce a refrigerant such as air introduced from the outside.

  In the motor drive inverter unit 20 configured as described above, the switching elements 3a, 3b, 3c, 4a, 4b, and 4c are efficiently cooled by the same operation as described in the first embodiment.

  In particular, since the heat radiating portions 34A and 34B are cooled by the external refrigerant, the switching elements 3a, 3b, 3c, 4a, 4b, and 4c are more efficiently cooled.

  Instead of cooling the heat radiating portions 34A and 34B with the refrigerant, the heat radiating portions 34A and 34B may be installed at a place where the flow of wind is good, such as the rear side of the grill of the vehicle.

{Third embodiment}
Next, a motor driving inverter unit incorporating a power device cooling apparatus according to a third embodiment of the present invention will be described. Note that the same components as those described in the second embodiment are denoted by the same reference numerals, description thereof is omitted, and differences will be mainly described.

  FIG. 5 is a perspective view showing an inverter unit for driving a motor according to the third embodiment, and FIG. 6 is an enlarged explanatory view of a main part of the inverter unit for driving a motor.

  The motor driving inverter unit 50 includes conductive members 60A and 60B having a structure for cooling by flowing a refrigerant instead of the conductive members 30A and 30B having a heat pipe structure as described above.

  Each of the conductive members 60A and 60B is formed of a conductive material such as metal, and includes bases 62A and 62B and lead pieces 64A and 64B.

  The bases 62A and 62B are formed in an elongated plate shape. Flow paths 63A and 63B are formed in the bases 62A and 62B along the longitudinal direction thereof, and a predetermined refrigerant is caused to flow through the flow paths 63A and 63B.

  The high arm side switching elements 3a, 3b, 3c are provided on one surface side of the base body 62A, and the low arm side switching elements 4a, 4b, 4c are described on the one surface side of the base body 62B in the second embodiment. It is mounted and fixed in the same manner.

  The bases 62A and 62B are not necessarily formed in a plate shape, but in terms of ease of mounting and fixing the switching elements 3a, 3b, 3c, 4a, 4b, and 4c, the bases 62A and 62B have a predetermined plane. It is preferable that it is a shape with, for example, a plate shape.

  In addition, lead-out pieces 64A and 64B are formed so as to extend while being appropriately bent to the sides of the base bodies 62A and 64B. In the state where the base bodies 62A and 62B are attached and fixed at predetermined positions in the case body 22, the lead pieces 64A and 64B reach one side surface of the case body 22 while appropriately bending so as to avoid contact with the peripheral members. From there, it extends to the outside of the case body 22. The extended end portions of the drawing pieces 64A and 64B are each connected to an external power source via a power cable (not shown).

  The conductive members 60 </ b> A and 60 </ b> B extend the bases 62 </ b> A and 62 </ b> B into the first space 24 of the case body 22 and extend the leading ends of the drawn pieces 64 </ b> A and 64 </ b> B outward from the side surfaces of the case body 22. In the state, it is fixed in the case body 22.

  In this state, an inlet pipe 77 for introducing the refrigerant and a discharge pipe 78 for discharging the refrigerant are connected to one end of each of the base bodies 62A and 62B. The introduction pipe 77 and the discharge pipe 78 are fixed to one side surface of the case body 22 so as to protrude outward.

  In addition, one end and the other end of the insulating tube 79 disposed in the second space 25 are connected to the other end of each of the bases 62A and 62B.

  An external refrigerant supply pipe is connected to the introduction pipe 77, and a discharge pipe is connected to the discharge pipe 28. Then, the refrigerant from the refrigerant supply source is introduced into the flow path 63A in the base 62A on the one side through the introduction pipe 27 from the supply pipe. The refrigerant flows through the flow path 63A in a predetermined direction, passes through the insulating tube 79, and is introduced into the flow path 63B in the base 62B on the other side. Further, the refrigerant flows through the flow path 63B, flows from the discharge pipe 28 through the discharge pipe, and is discharged to the outside. The refrigerant cools the bases 62A and 62B when the refrigerant flows through the flow paths 63A and 63B.

  Note that the refrigerant may circulate through a cooling mechanism (not shown), or may introduce a refrigerant such as air introduced from the outside.

  In the motor drive inverter unit 50 configured as described above, the heat generated in each of the switching elements 3a, 3b, 3c, 4a, 4b, and 4c is transmitted to the bases 62A and 62B and cooled there. Therefore, the switching elements 3a, 3b, 3c, 4a, 4b, 4c are efficiently cooled.

  In particular, since the bases 62A and 62B are cooled by the flow of the refrigerant, the switching elements 3a, 3b, 3c, 4a, 4b, and 4c are more efficiently cooled.

{Fourth embodiment}
In the fourth embodiment, a mode in which the motor driving inverter unit is assembled around the motor will be described.

  FIG. 7 is a perspective view showing a state where the motor drive inverter unit 80 is assembled to the motor housing 12H.

  As described in the second embodiment or the third embodiment, the inverter unit 80 includes switching elements 3a, 3b, 3c, 4a which are elements forming the inverter circuit shown in FIG. 4b, 4c, conductive members 30A, 30B or conductive members 60A, 60B, and a cooling structure.

  Around the outer periphery of the case body 22 are a gate signal input connector section 82, an introduction pipe 83 serving as a refrigerant inlet / outlet, a discharge pipe 84, and power supply terminals 85a and 85b corresponding to the U phase, V phase and W phase. , 85c, and an external power cable 86 is drawn out. The case body 22 is provided with a connector portion 88 that is interposed between each line of the power source and connects a capacitor for stabilizing the power source and smoothing during power generation.

  A power receiving terminal (not shown) that can be directly connected to each of the power supply terminals 85a, 85b, 85c is provided on the housing 12H side of the motor.

  The power supply terminals 85a, 85b, and 85c are connected to the power receiving terminals on the motor housing 12H side, so that the inverter unit 80 can be attached to the housing 12H using a known attachment structure such as screwing. ing.

  In this inverter unit 80, the circuit for driving the motor and the power supply terminals 85a, 85b, 85c that are directly connected to the power receiving terminal on the motor side and flow the driving current to the motor are integrated. External wiring for connecting the driving circuit and the motor can be omitted and the connection can be easily performed.

  When attention is paid to such advantages, the inverter unit 80 does not have to incorporate the configuration related to cooling as described in the second and third embodiments.

  In general, a cooling mechanism using a coolant such as cooling water is incorporated in a motor (engine motor) for driving a hybrid car. In this embodiment, an inverter unit 80 is provided in the motor housing 12H. Therefore, the refrigerant flow path used for cooling the motor is branched and led to the introduction pipe 83 side on the inverter unit 80 side (parallel connection), or upstream of the refrigerant flow path for the motor. The refrigerant can be led to the inverter unit 80 side (serial connection) on the side or downstream side. Thus, the refrigerant supply path and the discharge path (or the reflux path) can be shared, and the configuration can be simplified.

  Instead of providing the connector portion 82 for connecting the gate signal input capacitor and the capacitor to the case body 22, a connector is connected from the case body 22 to the tip portion as in the inverter unit 80B shown in FIG. The cables 82K and 88K may be pulled out and the cables 82K and 88K may be connected to an external gate drive circuit or a capacitor.

It is a perspective view which shows the power device cooling device which concerns on 1st Embodiment of this invention. It is a block diagram which shows the electric constitution of the electric power system in a hybrid car. It is an electric circuit diagram of an inverter. It is a partially broken perspective view which shows the whole structure of the inverter unit for motor drive which concerns on 3rd Embodiment of this invention. It is a perspective view which shows the inverter unit for motor drive which concerns on 3rd Embodiment. It is principal part expansion explanatory drawing of the inverter unit for motor drive same as the above. It is a perspective view which shows the state which assembled | attached the motor drive inverter unit to the housing of the motor. It is a perspective view which shows a modification.

Explanation of symbols

3a, 3b, 3c, 4a, 4b, 4c Switching element 11 Inverter 12 Motor 20 Motor drive inverter unit 22 Case body 30A, 30B Conductive member 32A, 32B Base body 34A, 34B Heat radiation part 35a, 35b, 35c Feeding terminal 50 Motor drive Inverter unit 60A, 60B Conductive member 62A, 62B Base 63A, 63B Flow path 80 Motor drive inverter unit 85a, 85b, 85c Feeding terminal 101 Power device 102 Element body 110 Conductive member 112 Base 113 Encapsulated space 114 Heat radiation part

Claims (5)

A power device having an element body and a connector;
A conductive member for connecting the connector and electrically connecting the power device to another electrical element;
With
The conductive member is a power device cooling apparatus having a cooling structure. The power device cooling device according to claim 1,
The conductive member as the cooling structure,
A heat pipe structure in which a liquid is enclosed in an enclosed space formed therein, and cooling is performed using vaporization and vaporization of the liquid in the enclosed space;
Or
A power device cooling apparatus having a structure in which cooling is performed by flowing a refrigerant in a flow path formed therein.   An inverter unit for driving a motor incorporating the power device cooling device according to claim 1. A circuit for driving the motor;
A power supply terminal that is directly connected to the power receiving terminal on the motor side and allows a driving current to flow through the motor;
Inverter unit for motor drive built in a single case in an integrated form. The motor drive inverter unit according to claim 4,
An inverter unit for driving a motor, wherein the power device cooling device according to claim 1 or 2 is applied to a power device used in a circuit for driving a motor and a conductive member connected thereto.

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