JPH11340393A - Power-converting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve radiation performance to reduce the size, and to improve the reliability of a semiconductor mounting structure in a power-converting device. SOLUTION: In semiconductor module 101, a semiconductor switching element 1 and a diode 2 are soldered to a heat reception member 6 that is made of copper as a material with solder 4 and 5 through an insulating substrate 3. The heat reception member 6 is composed of a base thickness part and a fin 7, and nickel plating or tin plating is preferably performed at least at a side for mounting the element. On each of six insulating substrates 3, a main circuit part corresponding to the upper or lower arm of two phases out of three ones is mounted. In this embodiment, two semiconductor switching elements and two diodes are mounted onto one insulating substrate 3. Six insulating substrates with such a configuration are mounted to one heat reception member 6, and a three-phase inverter main circuit is constituted to reduce the size. On the lower surface of the heat reception member 6, the fin 7 is formed in a direction vertical to the element-mounting surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power converter, for example, a power converter installed in an electric vehicle or the like for controlling an electric motor.

[0002]

2. Description of the Related Art As a conventional power converter, for example, as described in JP-A-7-211832, a metal matrix material liquid cooling heat sink structure comprising a base and a lid, the metal matrix material liquid cooling An insulating layer overlying the heat sink structure, the insulating layer comprising an insulating layer integrally formed with the metal matrix material liquid cooling heat sink structure, and an electronic circuit overlying the insulating layer. What is done is publicly known.

[0003]

According to such a power conversion device, the metal matrix material used as the heat receiving member has a heat conductivity of less than half that of copper, and the heat resistance of the heat receiving member portion is low. It was big. In addition, when fins and the like are provided to compensate for this, the so-called fin efficiency is low due to low thermal conductivity, so that the thermal resistance is also high. Moreover, aluminum, which is a main constituent element of the metal matrix member, has the best cooling ability as a liquid, and is highly corrosive to commonly used water,
In the worst case, a hole is formed in the metal matrix member, causing an obstacle to the electric components, and thus there is a problem in reliability.

An object of the present invention is to provide a power conversion device,
An object of the present invention is to provide a power converter that has high reliability and can significantly improve heat radiation performance.

[0005]

The object of the present invention is to provide a power converter having a number of semiconductor elements, an insulating layer, a heat receiving member and a lid, wherein a plurality of the semiconductor elements are thermally connected to one side of the insulating layer. Connected and attached, the heat receiving member is made of copper, and is thermally connected and attached to the other side of the insulating layer, and the heat receiving member has a surface opposite to the surface on which the insulating layer is formed. Fins are formed, and the lid is fitted to the heat receiving member to achieve a configuration in which a flow path for flowing liquid from outside is formed.

The object is to provide a power conversion device having a number of semiconductor elements, an insulating layer, a heat receiving member, and a lid, wherein the plurality of semiconductor elements are thermally connected to one side of the insulating layer. The heat receiving member is made of copper, is thermally connected to and attached to the other side of the insulating layer, and a fin is formed on a surface of the heat receiving member opposite to a surface on which the insulating layer is formed. By fitting the lid to the heat receiving member, a flow path for flowing a liquid from the outside is formed, copper is used as the material of the heat receiving member, and from the surface of the heat receiving member to which the electric insulating plate is attached to the fin root surface. This is achieved by a configuration in which the thickness is 3 mm or more.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

First, a power converter according to the present invention will be described with reference to FIG. FIG. 6 shows a main circuit diagram of a power conversion device for an electric vehicle. The power converter of the present embodiment converts a DC current from a battery 201 into an AC current having a variable voltage and a variable frequency via an inverter circuit to control a three-phase AC motor 206. Inverter circuit 205u,
A filter capacitor 202 for removing a ripple component of the DC current from the battery 201 is connected to the DC side of 205v and 205w. The main circuit of the inverter circuit includes a semiconductor switching element 203 such as an IGBT and a freewheel diode 204, for example.

The inverter circuit corrects the input direct current
By outputting a pulse having two negative levels, P
A WM-modulated variable voltage variable frequency three-phase alternating current is output. The rotation of the three-phase motor 206 is controlled by inputting an alternating current having a variable voltage and a variable frequency, so that the automobile runs. Also, at the time of regenerative operation in which the electric motor 206 operates as a generator, energy flows to the battery 201 contrary to the above-described power running.

[0010] Among the elements constituting the power converter described above, the heat generated by the semiconductor switching element 203 and the diode 204 is particularly large, so that the size of the cooler must be increased. In addition, since the amount of heat generated varies depending on the running mode, a temperature cycle is applied to the joints of the wires that take out electricity from each element and the soldering parts that join each component, causing fatigue fracture at each joint. , Which has hindered the improvement of reliability. The capacitor according to the present embodiment described below can meet these requirements.

Next, a power converter according to the present invention will be described with reference to FIGS. FIG. 1 is a side sectional view of the power converter of the present invention, FIG. 2 is a side view seen from the direction A in FIG.
1 is a side view seen from the direction B in FIG. 1, and FIG. 4 is a cross-sectional view taken along the line CC in FIG.

The semiconductor module 10 according to the present embodiment
Reference numeral 1 denotes a semiconductor switching element 1 and a diode 2 joined to a heat receiving member 6 made of copper using solders 4 and 5 via an insulating substrate 3. The heat receiving member 6 is composed of a base portion and fins 7 indicated by dimension lines in the drawing, and it is desirable that at least the element mounting surface side be plated with nickel or tin. As the type of the insulating substrate 3 using solder, for example, aluminum nitride or alumina is used. There are a total of six insulating boards, and on each board, main circuit components corresponding to the two-phase upper arm or lower arm of the three phases are mounted.

In this embodiment, two semiconductor switching elements and two diodes are mounted on one insulating substrate 3. Six of the insulating substrates having such a configuration are 1
By mounting on three heat receiving members 6 to form a three-phase inverter main circuit, miniaturization is possible. Fins 7 are formed on the lower surface of the heat receiving member 6 in a direction perpendicular to the element mounting surface.

The fins 7 are integrally formed from the heat receiving member 6 or joined by a method such as brazing. The flow path 10 through which the liquid flows is formed by a combination of the flange 13, the lid 9, the fin 7, and the heat receiving member 6.

In this embodiment, the flange is on the heat receiving member side, but may be on the lid side. In this case, for example, by forming the lid 9 from aluminum, the semiconductor module 10
1 can be reduced in weight. The liquid inlet 11a and the liquid outlet 12a are connected to the connection pipe 8, respectively.
The liquid reaches the branch buffer 12a via the pipe 8 and the inflow port 11a, branches into the respective channels 10 from there, and flows downstream while absorbing the heat generated by the semiconductors 1 and 2 that generate heat in the channels. Further, the liquid leaves the semiconductor module 101 via the merging buffer 12b and the outlet 11b. Here, as the type of liquid used for cooling, there are water having high cooling performance and an ethylene glycol aqueous solution in consideration of use in cold regions.

Next, the relationship between the base thickness of the heat receiving member used for the semiconductor module 101 in the power converter of the present invention and the cooling performance will be described with reference to FIG. The graph of FIG. 5 shows the thermal resistance from the semiconductor switching element to the cooling liquid when the heat receiving member 6 and the fins are made of copper or aluminum-silicon carbide and the base thickness of the heat receiving member 6 is changed. It is. Thermal resistance is 1mm thick using aluminum-silicon carbide (thermal conductivity about 160W / mK)
The ratio is shown based on the thermal resistance in the case of (1). According to this, when aluminum-silicon carbide is used, the thermal resistance increases as the base thickness increases.

On the other hand, when copper is used, a "bathtub"
The curve is shaped like a circle, and has a minimum value in the range of 3 to 7 mm. This is because, when copper having good thermal conductivity (heat conductivity of about 400 W / mK) is used as the material of the heat receiving member 6, the thickness in the vertical direction increases due to the increase in thickness, and the temperature difference increases. This is because there is a region having a thickness where heat diffusion in the direction parallel to the mounting surface is good, in addition to the occurrence of. This tendency is remarkably exhibited by a material having a high thermal conductivity, and copper is most remarkable in practical use.

According to the power converter, the semiconductor switching element 1 and the diode 2 are joined to the heat receiving member 6 made of copper using the solders 4 and 5 via the insulating substrate 3. Since the heat receiving member and the fin are made of a material having excellent thermal conductivity, the cooling performance can be improved.

Further, in the above configuration, by setting the base thickness of the heat receiving member 6 to 3 mm or more, the cooling performance can be further improved, and the size of the device can be reduced and the reliability of the mounting portion can be improved.

Although the embodiment of the power conversion device in the inverter device for driving the induction motor for the electric vehicle has been described above, the present invention is not limited to this, and for example, direct current is supplied to a railway vehicle. Thus, the present invention can also be applied to an inverter system that drives an induction motor. In the inverter described above, the converter is a two-level power converter, but may be a three-level power converter. Furthermore, although only the configuration employing an IGBT as the switching element has been described, the invention can be applied to all switching elements employing a planar mounting and single-sided cooling package structure such as a power transistor or MOSFET.

[0021]

According to the power converter of the present invention, it is possible to provide a small and long-life power converter having remarkably improved heat radiation performance. The reliability of the semiconductor mounting structure can be significantly improved.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a power converter according to a first embodiment of the present invention.

FIG. 2 is a plan view in the direction A of FIG. 1;

FIG. 3 is a side view in the B direction of FIG. 1;

FIG. 4 is a sectional view taken along line CC of FIG. 1;

FIG. 5 is a graph showing calculation results for explaining the operation of the present invention.

FIG. 6 is a main circuit diagram of the power converter of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Semiconductor switching element, 2 ... Diode, 3 ... Insulating board, 4, 5 ... Solder, 6 ... Heat receiving member, 7 ... Fin, 8
... Connection pipe, 9 ... Lid, 10 ... Flow path, 11a ... Liquid inlet, 11b ... Liquid outlet, 12a ... Branch buffer, 1
2b: merge buffer, 13: flange, 101: semiconductor module, 201: battery, 202: filter capacitor, 203: semiconductor switching element, 204: diode, 205u: inverter U phase, 205v: inverter V phase, 205w: inverter W phase , 206 ... three-phase motor.

Claims (1)

[Claims] 1. A power converter having a plurality of semiconductor elements, an insulating layer, a heat receiving member, and a lid, wherein the plurality of semiconductor elements are thermally connected to one side of the insulating layer. Is made of copper, is thermally connected to and attached to the other side of the insulating layer, and a fin is formed on a surface of the heat receiving member opposite to a surface on which the insulating layer is formed, A power converter, wherein a flow path for flowing a liquid from outside is formed by fitting a lid to the heat receiving member.