JPH03108749A - Transistor module for power converter - Google Patents

Abstract

PURPOSE:To enable reduction in wiring inductance for connection of a transistor and an asymmetric device and high dissipation of heat generated from the asymmetric device by placing both devices in a container, and by fixing an electrode of each device to a connection conductor on the container's bottom plate. CONSTITUTION:A transistor 41 and an asymmetric device 43 of small forward- voltage drop and high reverse-voltage drop are placed in a container 11-13. An electrode of each device 41, 43 is fixed to a connection conductor on a container's bottom plate 11, and its other electrodes are connected to the other connection conductors 31, 33, and 34 via wires 5, and the conductors 31-34 are led out of the container's parts 11-13 (bottom plate, side wall, and upper cap) to form outer terminals 61-64 (emitter, collector, base and cathode), respectively. For example, copper-made connection conductors 31-34 are fixed on the copper- made container's bottom plate 11 via an insulating substrate 2. The transistor chip 41, diode chip 42, and a constant voltage diode chip 43 are fixed on the connection conductor 32 by the bottom collector electrode, bottom cathode electrode, and bottom anode electrode, respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a transistor module used in a power conversion device, which is composed of transistors and a snubber circuit consisting of an asymmetric element and a capacitor for protecting the transistors. .

[Conventional technology]

Semiconductor devices for power conversion devices using transistors are usually made as modules, and consist of only a transistor or a diode connected in parallel or series with the transistor, which allows current to flow in the opposite direction or the same direction as the transistor. They were fixed on the same substrate and housed in a single container, and an external terminal for passing the main current and a terminal for driving the transistor were provided on the outer periphery of the container.

In a power conversion device configured with such a transistor module, a surge voltage generated by the floating inductance of the circuit is applied to the device when the transistor is turned off or the diode reversely recovers, and there is a risk that the device will be destroyed.

Also, the rise of the voltage between the terminals of the transistor (dν/dt
) is steep, malfunctions of other transistors or control circuits may occur. As a countermeasure to this, there is a method of connecting an R-C snubber consisting of a resistor and a capacitor connected in series in parallel to the transistor, or an R-C snubber consisting of a capacitor connected in series with a diode and resistor connected in parallel.
- Methods of connecting CD snubbers are known. However, in the R-C-D snubber, the resistance is large, the forward voltage drop of the snubber diode is large, and a high dν/dt occurs when the snubber circuit diode reverse recovers, which can cause malfunction in the control circuit. The R-C snubber has drawbacks such as large energy loss as the accumulated charge in the capacitor is discharged through the resistor, and the resistor becomes large. In order to solve these drawbacks, the present inventors have proposed an asymmetric element with a small forward voltage drop and a large reverse voltage drop between the terminals of the transistor, such as a series circuit of a voltage regulator diode and a capacitor. A method of parallel connection was announced at the 1989 Institute of Electrical Engineers National Conference (April 1989), and a patent application was filed in 1989.
It is described in the specification of No. 311. Figure 8 shows an example of such a circuit, in which diodes 22 are connected in antiparallel).
A series circuit of a constant voltage diode 23 and a capacitor 24 is connected in parallel between the collector and emitter of a transistor 21.

FIG. 9 shows an example of configuring a power conversion device using such a transistor module. Normally, as shown in this circuit diagram, one arm pair 110 is a unit in which two transistor modules 100 for the upper arm of the bridge circuit and a transistor module 101 for the lower arm are connected in series, and these are connected in parallel. A power conversion device is configured.

[Problem to be solved by the invention]

In a transistor module having a circuit as shown in FIG. 8, the collector (C) terminal of the transistor 21 and the anode (A) terminal of the constant voltage diode 23 are connected with a conductor, and the cathode (K) terminal of the constant voltage diode 23 is connected with a conductor. A capacitor 24 was connected between the emitter (E) terminal of the transistor 21 and the emitter (E) terminal of the transistor 21. However, such a configuration has the following problems.

(1) Voltage regulator diodes generate heat, which must be dissipated; however, snubber circuits are generally attached to wiring conductors installed on the top of the transistor element container, so heat cannot be dissipated sufficiently, making it difficult to maintain large chip sizes. Requires a voltage diode element.

(2) In order to solve the above problem, if a constant voltage diode element is installed on the same cooling body as the transistor element, the distance from the terminal of the transistor element becomes longer, and a separate wiring conductor is required for connection. becomes. Furthermore, the wiring between the capacitor and the terminal of the transistor becomes long, and the inductance of these wirings reduces the surge voltage absorption effect of the snubber circuit.

(3) Since the anode terminal of the voltage regulator diode is connected to the collector side of the transistor, a voltage of, for example, several hundred volts or more is applied between the emitter terminal and the cathode terminal, and the container to which these terminals are attached is It is difficult to downsize the device because it requires an insulation distance that satisfies the dielectric strength.

When configuring a power conversion device using the transistor modules, for example, as shown in FIG. 9, two modules, a transistor module 100 for the upper arm of the bridge circuit and a transistor module 101 for the lower arm, are connected in series. These are connected in parallel with one arm 110 connected to the upper arm as a unit, but when configuring one arm pair, the emitter terminal 61 of the transistor module 100 for the upper arm and the transistor module for the lower arm are connected as shown in FIG. Since the conductor 70 connecting the collector terminal 62 of the transistor module 101 passes above the base terminal 63 of the transistor module 100 for the upper arm, electromagnetic induction due to transient changes in the collector current flowing through this connecting conductor causes the conductor 70 to connect the collector terminal 62 of the transistor module 100 for the upper arm. There was a problem in that this affected the base wiring, causing the transistor to malfunction.

An object of the present invention is to solve the above-mentioned problems and to help reduce the inductance of the wiring in a transistor module for a power conversion device having a snubber circuit consisting of a series circuit of an asymmetric element and a capacitor. When configuring a power conversion device using a transistor module that can sufficiently dissipate the heat generated by the battery and also reduce the voltage applied between the emitter terminal and the cathode terminal, the upper arm of the bridge circuit To provide an arrangement of external terminals and their connection configuration that avoids the conductor connecting the emitter terminal of the transistor module for the lower arm and the collector terminal of the transistor module for the lower arm from passing over the base terminal of the transistor module for the upper arm. It is something.

[Means to solve the problem]

In order to solve the above problems, in a transistor module for a power conversion device of the present invention, a transistor and an asymmetric element having a small forward voltage drop and a large reverse voltage drop are housed in one container. One electrode of each element is fixed to one connecting conductor on the bottom plate, and the other electrodes of each element are connected to other connecting conductors via conductive wires, and the connecting conductors are each pulled out of the container and connected to the outside. so as to form a terminal. Furthermore, in the transistor module that constitutes the upper arm of the bridge circuit of the power converter, the collector of the transistor and the anode of the asymmetric element are fixed to one connecting conductor on the bottom plate of the container, and the connecting conductor is pulled out of the container and connected to the collector terminal. , the emitter of the transistor is connected with another connecting conductor, the connecting conductor is drawn out of the container to form an emitter terminal, the cathode of the asymmetrical element is connected with another connecting conductor, and the connecting conductor is connected with the other connecting conductor of the container. The transistor module, which is pulled out to form the cathode terminal and also forms the lower arm of the bridge connection, has the collector of the transistor fixed to one connection conductor on the bottom plate of the container, and that connection conductor is pulled out to the outside of the container. forming a collector terminal, the emitter of the transistor and the cathode of the asymmetric element are connected to another connecting conductor, and the connecting conductor is drawn out of the container to form an emitter terminal;
The anode of the asymmetrical element is fixed to another connecting conductor, and the connecting conductor is drawn out of the container to form an anode terminal, and is further connected to the transistor module constituting the upper arm and the transistor module constituting the lower arm. The emitter terminals and collector terminals are arranged in opposite directions so that the emitter terminals of the transistor modules constituting the upper arm and the collector terminals of the transistor modules constituting the lower arm are arranged and connected next to each other.

[Effect]

Heat generated in the asymmetric element fixed to the connection conductor on the container bottom plate can be easily radiated by attaching a cooling body to the container bottom plate. Since the asymmetric element can be fixed close to the transistor, no connection wiring is required, and the inductance caused by the wiring can be omitted. Furthermore, since the terminal for connecting the asymmetric element and the capacitor and the terminal for connecting the transistor and the capacitor can be provided close to each other, the wiring for connecting the capacitor can also be shortened, and the wiring inductance in this portion can also be reduced.

In addition, in the transistor module for the upper arm of the bridge circuit that constitutes the power conversion device, the anode of the asymmetric element is connected to the collector of the transistor, so the cathode terminal and the collector terminal are at almost the same potential. The insulation voltage between the two can be kept low. In the transistor module for the lower arm, the cathode of the asymmetric element is connected to the emitter of the transistor, so
Since the anode terminal and emitter terminal are at almost the same potential,
The dielectric strength voltage between these terminals is similarly kept low.

Furthermore, the arrangement of the external terminals of the transistor module for the upper arm and the arrangement of the external terminals of the transistor module for the lower arm are made opposite to each other so that the emitter terminal of the transistor module for the upper arm and the collector terminal of the transistor module for the lower arm are placed next to each other. Because of this arrangement, the terminals can be directly connected, and the connection conductor can be avoided from passing over the base terminal of the transistor module for the upper arm, as in the conventional case.

〔Example〕

FIG. 1 shows the arrangement of elements and parts in one embodiment of the present invention. For example, connection conductors 31, 32.3 made of copper are placed on a container bottom plate 11 made of copper via an insulating substrate 2.
3.34 is fixed. On the connection conductor 32, a transistor chip 41 is fixed by a collector electrode on the lower surface, a diode chip 42 is fixed by a cathode electrode on the lower surface, and a constant voltage diode chip 43 is fixed by an anode electrode on the lower surface. Although detailed illustrations are omitted for clarity, the emitter electrode on the top surface of the transistor chip 41 is connected to the connecting conductor 31, the base electrode is connected to the connecting conductor 33,
The anode electrode on the top surface of the diode chip 42 is connected to the connection conductor 31, and the cathode electrode on the top surface of the constant voltage diode chip 43 is connected to the connection conductor 34 by thin metal wires 5, respectively.

FIG. 2 shows the external appearance of a transistor module formed by assembling the side wall 12 and the top cover 13 on the bottom plate 11 shown in FIG. On the top cover 13 are external terminals, that is, an emitter (E) terminal 61, a collector (C) terminal 62, and a base (B) terminal.
A terminal 63 and a cathode (K) terminal 64 are provided. Emitter terminal 61 via a rising portion (not shown)
is connected to the connecting conductor 31, the collector terminal 62 is connected to the connecting conductor 32, the base terminal 63 is connected to the connecting conductor 33, and the cathode terminal 64 is connected to the connecting conductor 34. The snubber circuit capacitor 7 only needs to be connected between the emitter terminal 61 and the cathode terminal 64, which is extremely simple and requires only a short wiring length. In addition, the constant voltage diode 4
3 is radiated via the insulating substrate 2 and the container bottom plate 11.

This produces a transistor module having the circuit shown in FIG.

FIG. 4 shows a different embodiment of the invention. FIG. 4 (Al is a transistor module used for the upper arm of the bridge circuit when configuring the power conversion device, and Cb is a transistor module used for the lower arm. Figure 4 (a
The transistor module for the upper arm of IO is shown in Figure 5 (81
As shown in the figure, the anode (A) of a constant voltage diode 43 is connected to the collector of the transistor 41, and its external terminals are arranged from the left side to the emitter terminal 61. Collector terminal 62. The order is the cathode terminal 64. Fifth
As is clear from the circuit in Figure (al), the collector terminal 62 and the cathode terminal 64 are at almost the same potential, the dielectric strength voltage between the adjacent collector terminal 62 and the cathode terminal 64 may be low, and the insulation distance between them is The device can be miniaturized in a short time. Similarly, as shown in Fig. 4 (bl
In the lower arm transistor module, as shown in FIG. 5+bl, the cathode (K) of a constant voltage diode 43 is connected to the collector of the transistor 41, and the external terminals are arranged from the left side to the collector terminal 62. Emitter terminal 61. This is followed by the anode terminal 65. Figure 5 (
As is clear from the circuit of bl, the emitter terminal 61 and the anode terminal 65 are at almost the same potential, the insulation voltage between the adjacent anode terminal 65 and the emitter terminal 61 may be low, and the insulation distance is short, making the device compact. can be converted into

Furthermore, when making one arm pair 110 of a unit configuring a bridge circuit using these transistor modules,
As shown in FIG. 6, the upper arm transistor module 102 [same as FIG. 5 (8)] and the lower arm transistor module 103 [same as FIG. 5 (bl)] are connected in series, but in this case, In fact, the terminal arrangement in No. 4 is as shown in the physical layout of the transistor module in Figure 7, with the emitter terminal 61 and collector terminal 62 of the transistor modules for the upper arm and lower arm.
The emitter terminal 61 and collector terminal 62 of the transistor module are opposite to each other, and the emitter terminal 61 of the transistor module 102 for the upper arm and the collector terminal 6 of the transistor module 103 for the lower arm are opposite to each other.
2 are adjacent to each other, and by directly connecting them with a conductor, this connection conductor 70 does not pass through the upper part of the base terminal 63 of the transistor module for the upper arm, as in the conventional case, and this connection Vts This eliminates the problem that electromagnetic induction due to transient changes in the collector current flowing through the body 70 affects the base wiring of the transistor module 102 for the upper arm, causing this transistor to malfunction.

Although transistors are used in the above-mentioned embodiments, MO
The same method can be used when using a self-extinguishing semiconductor element such as an SFET or an insulated gate bipolar transistor (IGBT).

〔Effect of the invention〕

According to the present invention, by fixing the transistor and the asymmetric element of the snubber circuit that protects it on the bottom plate of one container, the wiring inductance for connecting the pixel elements can be reduced, and the wiring inductance generated in the asymmetric element can be reduced. Since heat can be sufficiently radiated from the container bottom plate through the cooling body, the chip size of the asymmetric element can be reduced.

In addition, to configure a snubber circuit consisting of an asymmetrical element and a capacitor, it is only necessary to connect a capacitor between the outer door terminals of the transistor module, which reduces the inductance of the snubber circuit and increases the surge voltage absorption effect. becomes possible.

Furthermore, when configuring a power conversion device, the transistor module for the upper arm of the bridge circuit connects the anode of the asymmetric element to the collector of the transistor, and the transistor module for the lower arm connects the cathode of the asymmetric element to the emitter of the transistor. In this way, the cathode terminal and the collector terminal, or the anode terminal and the emitter terminal are at approximately the same potential, so that the dielectric strength voltage between these terminals is kept low, and the insulation distance between them is shortened, so that the device can be made smaller.

Furthermore, the emitter terminals and collector terminals of the transistor modules for the upper arm and the lower arm are arranged oppositely to each other, and the emitter terminal of the transistor module for the upper arm and the collector terminal of the transistor module for the lower arm are adjacent to each other. By arranging the connecting conductor so that the connecting conductor has an effect on the base wiring of the transistor module for the upper arm, it is possible to prevent the transistor from malfunctioning.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the arrangement of elements and parts on the bottom plate of a container in a transistor module for a power conversion device according to an embodiment of the present invention, and FIG. 2 is a power conversion device assembled on the bottom plate of the container shown in FIG. 1. 3 is a circuit diagram of the transistor module for the power conversion device shown in FIG. 2, and FIG. 4 is a perspective view of a different example of the transistor module assembled on the bottom plate of the container shown in FIG. In the perspective views, (al is a perspective view of a transistor module for a power conversion device for the upper arm of the bridge circuit of the power conversion device, (b
1 is a perspective view of the transistor module for the power conversion device for the lower arm of the bridge circuit, and FIG. 5 is a circuit diagram of the transistor module for the power conversion device shown in FIG.
l is the circuit diagram of the transistor module for the power conversion device shown in FIG. 4 [8], (bl is the circuit diagram of the transistor module for the power conversion device shown in FIG. 4 (bl), and FIG. 6 is the circuit diagram of the transistor module for the power conversion device shown in FIG.
Figure 4 shows the transistor module for the power converter for the upper arm of l and the circuit diagram when the transistor module for the power converter for the lower arm of BLO is connected to one arm pair of the bridge circuit. FIG. 8 is a plan view showing the terminal arrangement of the transistor module for the upper arm power converter and the transistor module for the lower arm power converter in the circuit of FIG. A circuit diagram showing a method for connecting series circuits of capacitors in parallel (announced at the National Conference of the Institute of Electrical Engineers of Japan in 1989 and described in the specification of patent application No. 1-83118), Figure 9 is the transistor for the power conversion device shown in Figure 2. A circuit diagram of an example of a power conversion device configured using modules, and FIG. 10 is a plan view showing a terminal arrangement when two transistor modules for the power conversion device shown in FIG. 2 are connected to one arm pair of a bridge circuit. 11: Container bottom plate, 12: Container side wall, 13: Container top lid, 2
: Insulating board, 3L32, 33.34 : Connection conductor, 41
: I-Ransis transistor, 43: Constant voltage diode chip (asymmetric element chip), 5: Fine metal wire, 61: Emitter terminal (external terminal), 62: Collector terminal (external terminal), 63: Base terminal (external terminal), 64: Cathode terminal (external terminal), 65 near node terminal (external 9 (Q') (b') 4th feeder 3 (Q) (1)) Fig. 5 322

Claims (1)

[Claims] 1) A transistor and an asymmetric element having a small forward voltage drop and a large reverse voltage drop are housed in one container, and one connection conductor of each element is connected to one connection conductor on the bottom plate of the container. For a power converter device in which the electrodes are fixed, the other electrodes of each element are connected to other connecting conductors via conductive wires, and each of the connecting conductors is drawn out of the container to form an external terminal. transistor module. 2) In the transistor module that constitutes the upper arm of the bridge circuit of the power converter, the collector of the transistor and the anode of the asymmetric element are fixed to one connection conductor on the bottom plate of the container, and the connection conductor is pulled out of the container and connected to the collector. forming a terminal, the emitter of the transistor is connected with another connecting conductor, the connecting conductor is drawn out of the container to form an emitter terminal, the cathode of the asymmetrical element is connected with another connecting conductor, the connecting conductor is In the transistor module that is pulled out of the container to form a cathode terminal and also forms the lower arm of the bridge connection, the collector of the transistor is fixed to one connection conductor on the bottom plate of the container, and that connection conductor is pulled out of the container. The emitter of the transistor and the cathode of the asymmetrical element are connected to another connecting conductor, which is led out of the container to form an emitter terminal, and the anode of the asymmetrical element is connected to another connecting conductor. The conductor is fixed to a conductor, and the connecting conductor is drawn out of the container to form an anode terminal, and the emitter terminal and collector terminal of the transistor module constituting the upper arm and the transistor module constituting the lower arm are arranged mutually. 1. A transistor module for a power conversion device, wherein the emitter terminal of a transistor module constituting an upper arm and the collector terminal of a transistor module constituting a lower arm are arranged side by side and connected to each other.