JP2006156476A - Power semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power semiconductor device containing a plurality of power modules which has a little surge voltage and can be reduced in size. <P>SOLUTION: The power semiconductor device comprises a cooling block having two cooling surfaces arranged nearly in parallel; the power modules which are each located on the individual cooling surfaces so as to hold the cooling block in between; fixed blocks which are each located on the individual power modules so as to hold the cooling blocks and the power modules in between; and a pair of main circuit board and control board which are arranged opposite to each other with the cooling block between, with the main circuit board arranged on one side of the cooling block and the control board arranged on the other side of the cooling block, and are arranged in a direction nearly perpendicular to the cooling surfaces of the cooling block. The fixed blocks are fixed to the main circuit board so that they may push the power modules against the cooling block. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a power semiconductor device, and more particularly to a power semiconductor device integrated with a cooling block.

Conventionally, in a power semiconductor device including a plurality of power modules, a plurality of power modules are juxtaposed on a flat cooling plate, and a control board and a main circuit board are connected to each power module (for example, Patent Documents). 1).
JP 2004-128099 A

  However, when the number of power modules increases, for example, when 10 power modules are used, the area of the cooling plate on which the power modules are arranged increases, and the control board and main circuit board also increase. There was a problem of increasing the size.

  In addition, an increase in the size of the control board and the main circuit board leads to an increase in the routing distance of the wirings provided on the respective boards. In particular, in the closed circuit formed on the main circuit board, the wiring routing distance is increased. When it is increased, the inductance of the closed circuit is increased, and a large surge voltage is generated at the time of switching of the power semiconductor device, so that the switching loss of the power semiconductor device is increased or a power chip having a high withstand voltage has to be used.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a power semiconductor device that includes a plurality of power modules and has a small surge voltage and can be miniaturized.

  The present invention includes a cooling block having two cooling surfaces arranged substantially in parallel, a power module arranged on each cooling surface so as to sandwich the cooling block, and a cooling block and a power module. A pair of main circuit boards and control boards arranged opposite to each other across the cooling block in a direction substantially perpendicular to the cooling surface of the cooling block, one fixed block arranged on each power module so as to sandwich The fixed block includes a main circuit board disposed on one side of the cooling block and a control board disposed on the other side of the cooling block, and the fixed block presses the power module against the cooling block. The power semiconductor device is fixed to a circuit board.

  In the power semiconductor device according to the present invention, a power module having a laminated structure and sandwiching the power module between the main circuit board and the control board can provide a small-sized power semiconductor device with a suppressed surge voltage.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In the following description, “top”, “bottom”, “left”, “right” and names including these terms are used as appropriate, but these directions facilitate understanding of the invention with reference to the drawings. Therefore, a mode in which the embodiment is inverted upside down or rotated in an arbitrary direction is naturally included in the technical scope of the present invention.

Embodiment 1 FIG.
FIG. 1 is a cross-sectional view of the power semiconductor device according to the first embodiment, the whole being represented by 100. 2 is a cross-sectional view of FIG. 1 when viewed in the II direction.
The power semiconductor device 100 includes a cooling block 1 provided with two cooling surfaces 10 arranged substantially in parallel on the upper and lower sides. The cooling block 1 is made of, for example, copper, and a coolant channel 2 is provided on the cooling surface 10.
On each cooling surface 10, the power module 3 is arranged so as to sandwich the cooling block 1, and the cooling block 1 and the power module 3 constitute a sub module.

  FIG. 3 is a cross-sectional view of the power module 3. The power module 3 includes a heat sink 31 made of, for example, copper, aluminum nitride, alumina, or the like. A power semiconductor element 33 is fixed on the heat radiating plate 31 by, for example, solder 32. The power semiconductor element 33 is made of, for example, an IGBT, a power FET, or a diode. The power module 3 further includes a main terminal 35 and a control terminal 36 connected to the power semiconductor element 33 by an aluminum wire 34. The main terminal 35 and the control terminal 36 are made of copper, for example. As shown in FIG. 3, the main terminal 35 is bent substantially perpendicularly in the vertical direction. The power semiconductor element 33 and the like are sealed with a sealing resin 37 made of, for example, an epoxy resin.

  FIG. 4 is a cross-sectional view of another power module, and the power module 3 may have a structure as shown in FIG. 4, the same reference numerals as those in FIG. 3 denote the same or corresponding parts. In the power module of FIG. 4, an insulating layer 38 made of an epoxy resin containing a filler such as alumina and a protective layer 39 made of a copper foil having a thickness of 100 μm, for example, are provided on the back surface of the heat radiating plate 3. The other structure is the same as that of the power module of FIG.

  The power semiconductor device 100 further includes a fixed block 4 arranged so as to sandwich the cooling block 1 and the power module 3 from above and below. The fixed block 4 is made of, for example, a PPS (Polyphenylene Sulfide) case.

  On the fixed block 4, a capacitor 5 such as a smoothing capacitor is attached by an adhesive, for example, as necessary.

  Further, the cooling block 1 is cooled so that the pair of main circuit boards 6 and the control board 7 are located on the left side of the cooling block 1 and the control board 7 is located on the right side of the cooling block 1. It is arranged substantially perpendicular to the surface 10. The main circuit board 6 and the control board 7 are opposed to each other with the cooling block 1 interposed therebetween. The main circuit board 6 is preferably a bus bar board in which copper alloy wiring is provided on both sides of the insulating plate. The control board 7 is a printed board.

The main terminal provided on the left surface of the power module 3 is bent in the vertical direction along the main circuit board 6 and is fixed to the fixing block 4 by a fixture 8 that penetrates the main terminal and the main circuit board 6. ing. The fixing tool 8 is composed of, for example, a bolt and a nut attached to the fixing block 4. Bolts and nuts are arranged at positions that do not interfere with the refrigerant flow path 2 of the cooling block 1.
On the other hand, the control terminal provided on the right surface of the power module 3 is connected to the control board 7 with solder or the like so as to penetrate the control board 7.

  In the power semiconductor device 100, the fixing block 4 is fixed to the main circuit board 6 by the fixing tool 8, so that the fixing block 4 presses the power module 3 in the vertical direction against the two cooling surfaces 10 of the water cooling block 2. It is like that. For this reason, the refrigerant flow path 2 is sealed by the power module 3 by fixing the fixing block 4 to the main circuit board 6.

  The power semiconductor device 100 according to the first embodiment can be downsized by having such a structure, and can suppress a surge voltage to a small value. This will be described in detail below.

In the power semiconductor device 100, a large current is switched. However, if the inductance of the circuit is large, a surge voltage at the time of switching becomes large, which causes destruction of the power semiconductor element. Therefore, in order to prevent the destruction of the power semiconductor element, it is necessary to increase the withstand voltage level of the power semiconductor element. As a result, it is necessary to increase the width of the guard ring and the thickness of the chip. Problem arises.
In addition, when the surge voltage is large, a loss at the time of switching increases, and there arises a problem that the cooling performance needs to be improved.

  For this reason, the power semiconductor device 100 is configured to reduce the circuit inductance and reduce the surge voltage. Specifically, among the main terminals of the power module, since the inductance increases when the distance from the P terminal and the N terminal to the smoothing capacitor (wiring distance of the main circuit board) is large, the distance is shortened.

  That is, in the power semiconductor device 100 according to the first embodiment, as shown in FIG. 1, the main circuit board 6 and the control board 7 are disposed so as to sandwich the power module 3 and the capacitor 5. As a result, the P terminal and N terminal of the power module 3 and the electrode of the capacitor 5 are arranged at very close positions, the wiring of the main circuit board 6 connecting them can be shortened, and the inductance is reduced.

  As can be seen from FIG. 2, even when a plurality of semiconductor modules 3 and capacitors 5 are included, each of the semiconductor modules 3 and the capacitors 5 is disposed with the fixed block 4 interposed therebetween, and the main circuit board 6 is disposed on the side thereof. ing. For this reason, the wiring of the main circuit board 6 connecting each semiconductor module 3 and the capacitor 5 is substantially straight, and the wiring distance can be shortened.

  Further, in the power semiconductor device 100 according to the first embodiment, as shown in FIG. 2, since the back surface of the power module 3 is directly cooled by a coolant such as cooling water in the coolant channel, high cooling efficiency is obtained. Can do.

  In particular, in the power semiconductor device 100 of FIG. 2, the power module 3 is arranged on each of the two cooling surfaces of the cooling block 1, so that the power semiconductor device is compared with the case where the power module 3 is arranged on one side of the cooling block 1. 100 can be reduced in size.

  The capacitor 5 is fixed to the fixed block 4 with, for example, an adhesive. However, since the power module 3 generates a large amount of heat, the temperature increase of the capacitor 5 can be suppressed by reducing the thermal conductivity of the fixed block 4. It is preferable. In this case, if the thermal conductivity of the fixed block 4 is, for example, about 0.1 W / mK, a thermal resistance of several tens of degrees Celsius / W can be obtained, and the temperature rise of the capacitor 5 can be sufficiently suppressed.

Next, FIG. 5 is a bus bar substrate which is an example of the main circuit substrate 6 included in the power semiconductor device 100 according to the first embodiment. In a bus bar substrate, a metal wiring called a bus bar mainly made of a copper alloy or an aluminum alloy is formed on both surfaces of an insulating plate. For example, a current of several hundred amperes has a current of several hundred amperes to several thousand volts. It flows with a potential difference. Specifically, the bus bar substrate is obtained by fixing a bus bar made by stamping a 1 mm-thick copper alloy by pressing, on both surfaces of an insulating plate such as a mica sheet, an insulating sheet, and insulating paper, for example, with an adhesive. Make it.
The bus bar substrate of FIG. 5 has a structure having two sets of P bus bar, N bus bar, U wiring, V wiring, and W wiring on an insulating plate.

  When the bus bar substrate is used as the main circuit substrate of the power semiconductor device 100, the bus bar substrate is preferably formed as follows. For example, a closed circuit from the P terminal of the battery (power source) to the N terminal of the battery via the P bus bar, the power module, and the N bus bar acts as an inductance. When this inductance is large, a high surge voltage is generated during switching of the power module, leading to destruction of the power semiconductor element. For this reason, it is necessary to increase the withstand voltage characteristics of the power module and the power semiconductor element, and there is a problem that the power module and the power chip are increased in size.

  Moreover, the surge voltage is suppressed by attaching a surge absorption circuit called a snubber capacitor or a smoothing capacitor to the closed circuit. When such a capacitor is used, the bus bar connecting the P and N electrodes of the capacitor and the P and N electrodes of the power module becomes a closed circuit and has an inductance component. Since the magnitude of the inductance is proportional to the area surrounded by the closed circuit, it is effective to reduce the inductance to reduce the inductance. That is, the inductance is reduced by reducing the distance between the P and N electrodes of the power module and bringing the P bus bar and the N bus bar closer to each other.

  Note that the bus bar can be made into a three-dimensional shape to reduce the cost, but in this case, since the insulation process between the bus bars becomes complicated, at least the connection portion with the battery, power supply, capacitor, power module, etc. is a flat shape. It is desirable to be. In addition, it is desirable that the electrodes of the battery, the power source, and the capacitor are arranged so as to be positioned on the same plane as the bus bar.

FIG. 6 is a circuit diagram of an inverter in which the bus bar substrate of FIG. 5 is used, and includes two three-layer inverter circuits A and B.
When the power module has a so-called 2-in-1 configuration (one cooling block and two power modules constitute a submodule), a portion indicated by a dotted line in FIG. 6 is one submodule. One three-phase inverter circuit can be configured by combining three submodules. By forming a three-phase inverter circuit on each of the two cooling surfaces of the cooling block, two inverter circuits can be formed with a width of one cooling block.

Embodiment 2. FIG.
FIG. 7 is a cross-sectional view of the power semiconductor device according to the second embodiment, the whole being represented by 200. In FIG. 7, the same reference numerals as those in FIG. 1 denote the same or corresponding parts.
The power semiconductor device 200 has a structure in which the coolant channel 2 is embedded in the cooling block 1, and the other structure is the same as that of the power semiconductor device 100.

  Also in the power semiconductor device 200 using the refrigerant flow path 2, the same effect as the power semiconductor device 100 described above can be obtained.

It is sectional drawing of the power semiconductor device concerning Embodiment 1 of this invention. It is sectional drawing of the power semiconductor device concerning Embodiment 1 of this invention. It is sectional drawing of the power module concerning Embodiment 1 of this invention. It is sectional drawing of the other power module concerning Embodiment 1 of this invention. It is a top view of the bus-bar board | substrate concerning Embodiment 1 of this invention. 1 is a circuit diagram of a power semiconductor device according to a first embodiment of the present invention. It is sectional drawing of the power semiconductor device concerning Embodiment 2 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cooling block, 2 Refrigerant flow path, 3 Power module, 4 Fixed block, 5 Capacitor, 6 Main circuit board, 7 Control board, 8 Fixing tool, 9 Adhesive, 10 Cooling surface, 100 Power semiconductor device.

Claims (5)

A cooling block with two cooling surfaces arranged substantially parallel;
A power module arranged on each cooling surface so as to sandwich the cooling block;
A fixed block arranged on each of the power modules so as to sandwich the cooling block and the power module;
A pair of main circuit boards and a control board which are arranged to face each other across the cooling block in a direction substantially perpendicular to the cooling surface of the cooling block, and the main circuit board is arranged on one side of the cooling block And the control board disposed on the other side of the cooling block,
A power semiconductor device, wherein the fixed block is fixed to the main circuit board so that the fixed block presses the power module against the cooling block. 2. The power semiconductor device according to claim 1, wherein the cooling block includes a refrigerant flow path on each cooling surface, and the power module is disposed in contact with the refrigerant flow path. 2. The power according to claim 1, wherein the main terminal of the power module is bent along the main circuit board, and the main terminal and the main circuit board are fixed by a fixture that passes through the main terminal. Semiconductor device. 2. The power semiconductor device according to claim 1, wherein the main circuit board is formed of a bus bar board in which wiring layers are provided on both surfaces of an insulating plate. 5. The power semiconductor device according to claim 1, further comprising a capacitor fixed to the fixed block between the main circuit board and the control board.

Images