JP2009033799A - Cooling structure of three-level power conversion equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase the cooling capacity without being affected by the limit width in manufacture or the limit cooling capacity of a coolant. <P>SOLUTION: A plate-shaped mediating member 4 is interposed between semiconductor elements 1-3, such as switching elements or diode elements of an IGBT or the like, and coolants 5-6, and each semiconductor element 1-3, on its one side, and many coolants 5-6, on the other side, are fastened by screwing, so as to make one coolant. Since the plurality of coolants 5, 6, and 7 are coupled thermally by the plate-shaped mediating member 4, it becomes possible to substantially increase its thermal capacity. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a cooling structure for a semiconductor element constituting a power conversion device.

In recent years, there is an increasing demand for increasing the capacity of power conversion devices.
One of the means is to increase the voltage of the apparatus using a multi-level power converter (apparatus capacity = voltage × current), and the representative is a three-level power converter. An example of a three-level power converter is disclosed in Patent Document 1, for example. FIG. 4 is a circuit diagram showing one phase of the three-level inverter circuit disclosed in Patent Document 1. In FIG.

  In FIG. 4, Q1 to Q4 are, for example, IGBTs (insulated gate bipolar transistors) as switching elements, and CD1 and CD2 are diodes. In this power converter, the IGBTs Q1 to Q4 are turned on and off to generate AC power from the DC power supply PN and vice versa. In the three-level circuit, Q1 and Q2 and Q3 and Q4 are connected in series, so that a voltage twice as high as the device withstand voltage can be taken out as a device.

  FIG. 5 is a schematic diagram showing an example of the structure of FIG. Q1 to Q4 are IGBTs, CD1 and CD2 are diodes, and H is a cooling body for cooling them. The cooling body H is provided in order to remove heat generated from the IGBT and the diode during flow and keep the temperature below an allowable temperature. The IGBT and the diode are attached to the cooling body by screwing. In FIG. 5, the semiconductor elements Q1 to Q4, CD1 and CD2 for one phase are cooled by one cooling body H for the following reason.

FIG. 6 shows an example of heat generation sharing for each operation mode of the three-level circuit.
From the figure, it can be seen that in the three-level circuit, the heat generation share changes according to the power factor. For example, as shown in FIG. 6A, when the power factor is 1, even when Q1: 100 [W], Q2: 50 [W], and CD1: 50 [W], when the power factor = 0, FIG. As shown in (b), it changes like Q1: 50 [W], Q2: 100 [W], CD1: 50 [W].

  For this reason, for example, as shown in FIG. 7, if a cooling body is prepared for each semiconductor element, a total of 250 [W] cooling bodies are required. However, when cooling with the same cooling body as shown in FIG. 8, a cooling body for a total of 200 [W] is sufficient. For this reason, in a three-level circuit, it is more efficient to cool a plurality of semiconductors with the same cooling body.

JP 2005-160248 A

However, when the capacity of the power conversion device is further increased, there remains a problem with the cooling method as described in Patent Document 1 above. In other words, if the current is increased in addition to the increase in voltage to increase the capacity, the heat generation of the element further increases, and the cooling body becomes large in order to cope with this.
Accordingly, an object of the present invention is to increase the cooling capacity without being affected by the manufacturing limit width or the limiting cooling capacity of the cooling body.

In order to solve such a problem, the invention of claim 1 is a cooling structure of a semiconductor element constituting a three-level power converter,
A plate-like mediating member is interposed between the semiconductor element and the cooling body, and a plurality of semiconductor elements are fastened to one surface thereof, a plurality of cooling bodies are fastened to the other surface by screwing, One cooling body is used.

  In the first aspect of the invention, a heat transfer promoting mechanism utilizing boiling / condensation of refrigerant by any one of a heat pipe, a heat lane, and a vapor chamber can be used for at least a part of the mediating member. Invention). In the invention of claim 2, the mediating member can be divided into a plurality of parts (invention of claim 3).

  According to the present invention, in the cooling structure of the semiconductor element of the power converter, there is an advantage that the cooling capacity can be increased without being affected by the manufacturing limit width of the cooling body, the limit cooling capacity, and the like.

FIG. 1 is a block diagram for explaining an embodiment of the present invention.
FIG. 6 shows a cooling structure related to, for example, Q1, Q2, and CD1 in the three-level circuit shown in FIGS. That is, the cooling structure of FIG. 1A is composed of IGBTs 1 and 2 (Q1 and Q2), a diode 3 (CD1), a plate-like mediating member 4, and cooling bodies 5, 6 and 7. 6 and 7 have the same configuration as the conventional example shown in FIG. The IGBTs 1 and 2 and the diode 3 are screwed to the upper surface of the plate-like mediating member 4, and the cooling bodies 5, 6 and 7 are screwed to the lower surface of the plate-like mediating member 4.

  Further, as the plate-like mediating member 4, a plate-like material having good thermal conductivity such as copper or aluminum is used, and a compound having high thermal conductivity is provided on the contact surface between each element and the plate-like mediating member 4. Is applied. Each cooling body 5, 6, 7 is formed of a base plate 71 and a wing 72, and a material having good thermal conductivity such as copper or aluminum is used as the material thereof. The base plate 71 and the wing 72 are joined by brazing, caulking, or the like. Each of the cooling bodies 5, 6, and 7 has a width dimension of 250 [mm] and a cooling capacity of 200 [W] as in the conventional example shown in FIG.

  With such a configuration, the heat generated from the IGBTs 1 and 2 and the diode 3 is transmitted to the cooling bodies 5, 6 and 7 via the plate-like mediating member 4 and finally released to the outside air. Even if the IGBT 1 generates a protruding amount of heat compared to other elements, the heat is transferred to the cooling bodies 6 and 7 via the plate-like mediating member 4 and is radiated, so that the protruding state remains. There is no temperature.

  Further, in FIG. 1A, the plurality of cooling bodies 5, 6, and 7 are thermally coupled by the plate-like mediating member 4. Therefore, unlike the conventional example as shown in FIG. 1B, a large cooling capacity can be obtained regardless of the manufacturing limit size of the cooling body. For example, in the example of FIG. 1A, the cooling capacity is increased to 300 + 150 + 150 = 600 [W]. That is, the capacity of the apparatus is increased.

FIG. 2 shows another embodiment of the present invention. 2A is a perspective view, and FIG. 2B is an AA cross-sectional view thereof.
As is clear from FIGS. 2A and 2B, it differs from FIG. 1 in that a heat pipe 41 is embedded inside the plate-like mediating member 4. By providing the heat pipe 41, the thermal coupling between the cooling bodies 5, 6 and 7 is strengthened, and the temperature of the element can be further leveled.

FIG. 3 shows still another embodiment of the present invention.
This is a modification of FIG. 2 and is characterized in that the plate-like mediating member 4 is divided into 4A, 4B, and 4C. That is, when a heat pipe is embedded in a plate material, a method of making a through hole in the plate material and inserting the heat pipe there is generally used, but if the plate material becomes long, processing becomes difficult. Therefore, the plate-like mediating member 4 is divided to facilitate drilling.

  In the above description, a three-level circuit is used as the multi-level circuit. However, the present invention is not limited to this, and the comb fin is used as an example of the cooling body. However, the present invention is not limited to this. Furthermore, although the heat pipe is used as a heat conduction promoting mechanism utilizing the boiling / condensation of the refrigerant, it goes without saying that a heat lane, a vapor chamber, or the like can be used.

Configuration diagram for explaining an embodiment of the present invention The block diagram which shows another embodiment of this invention The block diagram which shows another embodiment of this invention Circuit configuration diagram showing a conventional example of a three-level circuit The block diagram which shows the structure of FIG. Explanatory drawing of heat generation sharing example in conventional 3-level circuit Configuration diagram showing a conventional split cooling body Configuration diagram showing a conventional integrated cooling body

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1, 2 ... IGBT (Insulated gate bipolar transistor), 3 ... Diode, 4, 4A, 4B, 4C ... Plate-shaped mediating member, 5, 6, 7 ... Cooling body, 71 ... Base plate, 72 ... Wings.

Claims (3)

A cooling structure of a semiconductor element constituting a three-level power converter,
A plate-like mediating member is interposed between the semiconductor element and the cooling body, and a plurality of semiconductor elements are fastened to one surface thereof, a plurality of cooling bodies are fastened to the other surface by screwing, A cooling structure for a three-level power conversion device, wherein the cooling structure is a single cooling body.   2. The three-level power converter according to claim 1, wherein a heat transfer promotion mechanism using boiling / condensation of a refrigerant by any one of a heat pipe, a heat lane, and a vapor chamber is used for at least a part of the mediating member. Cooling structure.   The cooling structure for a three-level power converter according to claim 2, wherein the mediating member is divided into a plurality of parts.

Images