JP2580798B2 - Transistor module for power converter - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transistor module used in a power conversion device including a transistor and a snubber circuit including an asymmetric element and a capacitor for protecting the transistor. .

[Conventional technology]

Transistor modules used in power converters consist of only transistors or diodes connected in parallel or in series with transistors and flowing current in the opposite direction or the same direction as the transistors, and these transistors and diodes are fixed on the same substrate. In addition, an external terminal that is housed in one container, and through which a main current flows, and a terminal that drives a transistor are provided on the outer peripheral portion of the container. Furthermore, in order to prevent the surge voltage generated by the floating inductance of the circuit from being applied when the transistor is turned off or the diode reversely recovers and the element is destroyed, Japanese Patent Application No. 1-8311 discloses
A method of connecting an asymmetric element having a small forward voltage drop and a large reverse voltage drop between terminals of a transistor, for example, a snubber circuit composed of a series circuit of a constant voltage diode and a capacitor in parallel has been proposed. FIG. 9 shows this circuit. In such a transistor module, the collector of the transistor 21 and the anode of the constant voltage diode 23 are connected by a conductor, and the capacitor 24 is connected between the cathode of the constant voltage diode 23 and the emitter of the transistor 21. However, such a configuration has the following problems.

(1) Since the constant voltage diode generates heat, it must dissipate heat. However, in general, the snubber circuit cannot be sufficiently dissipated because it is attached to the wiring conductor provided on the upper part of the transistor element container. Requires a constant voltage diode element.

(2) In order to solve the above problem, when a constant voltage diode element is mounted on the same cooling body as the transistor element, the distance from the terminal of the transistor element becomes longer, and another wiring conductor is required for connection. Becomes Further, the wiring between the capacitor and the terminal of the transistor becomes longer, and the inductance of these wirings reduces the surge voltage absorbing effect of the Suvana circuit.

On the other hand, according to Japanese Patent Application No. 1-161339, FIG.
A transistor module shown in FIG. 8 has been proposed. FIG. 6 is an arrangement diagram of each element and component in the above proposal. For example, connection conductors 31, 32, 33, and 34 made of copper are fixed on a container bottom 11 made of copper via an insulating substrate 2. I have. On the connection conductor 32, a transistor chip 41
Are fixed by the collector electrode on the lower surface, the diode chip 42 is fixed by the cathode electrode on the lower surface, and the constant voltage diode chip 43 is fixed by the anode electrode on the lower surface. The emitter electrode on the upper surface of the transistor chip 41 is the connection conductor 31, the base electrode is the connection conductor 33, the anode electrode on the upper surface of the diode chip 42 is the connection conductor 31, and the cathode electrode on the upper surface of the constant voltage diode chip 43 is the connection conductor. 34 are connected to each other by thin metal wires 5. FIG. 7 is an external view of a transistor module container in which the side wall 12 and the upper lid 13 are assembled on the bottom plate 11 shown in FIG. 6. The upper terminal 13 has external terminals, ie, an emitter (E) terminal 61 and a collector (C). ) Terminal 62, base (B) terminal 63 and cathode (K) terminal 64
Is provided. The emitter terminal 61 is connected to the connection conductor 31 and the collector terminal 62 is connected to the connection conductor via a rising portion (not shown).
32, the base terminal 63 is connected to the connection conductor 33, and the cathode terminal 64 is connected to the connection conductor. The snubber capacitor 7 is connected between the emitter terminal 61 and the cathode terminal 64. FIG. 8 shows an equivalent circuit thereof. The circuit is the same as FIG. 9 described above.

The output of this transistor module is determined by the capacity of the semiconductor elements used. However, since the capacity of these semiconductor elements is limited, in order to increase the output of the transistor module, a required number of these semiconductor elements are connected in parallel. Make a connection.

[Problems to be solved by the invention]

In the above-described transistor module for a power converter, a required number of semiconductor elements are connected in parallel in order to increase the output. In this case, however, each semiconductor element connected in parallel is connected to an external terminal of the transistor module. Since the positional relationship is different, the inductance of the wiring during this period is different, which causes a problem in the transistor that the ON and OFF times between the elements connected in parallel deviate, and the rated capacity of the element cannot be used sufficiently. is there. Even in the case of a constant voltage diode, there is a problem that a load is not evenly applied due to the deviation of the inductance, so that the rated capacity cannot be sufficiently used.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a transistor module having wirings of semiconductor devices connected in parallel and external terminals and having the same inductance.

[Means for solving the problem]

In order to solve the above-described problems, a transistor module according to the present invention includes a transistor element housed in one container and a forward / reverse asymmetric element having current / voltage characteristics on one connection conductor on a container bottom plate. The electrodes on one side are fixed with the electrodes on the lower side, and the electrodes on the other side are connected to different connection conductors via thin metal wires, respectively, and these connection conductors are drawn out of the container via the upper lid of the container. In the transistor module for a power conversion device, the transistor element and the asymmetric element each include a plurality of parallel connections, and the parallel connection separates at least the same type of element. Fixed on the connection conductor of the connection conductor and connected in parallel by the connection conductor, and the connection conductors connected in parallel have substantially the same length. Ranaru so to.

[Action]

The inductance of a wiring is basically proportional to the length of the wiring. In the transistor module of the present invention, among the semiconductor elements connected in parallel, at least the parallel connection includes one in which the same kind of element is fixed on another connection conductor and connected in parallel by a connection conductor, and the parallel connection is performed. Since the length of the connecting wire was made almost equal,
The inductances are approximately equal. In addition, since the positional relationship between each semiconductor element connected in parallel and the external terminal is different from each other, the connection conductor may be loosened in the middle in some cases, but in this case, the connection conductor should be fixed with the fastener shown in FIG. No problem arises.

〔Example〕

FIG. 1 is a wiring diagram of each semiconductor element connected in parallel and an external terminal in one embodiment of the present invention, and FIG. 2 is a plan view showing an arrangement of each semiconductor element and components in the embodiment of FIG. is there. This example shows a case where four transistors, four diodes, and two constant voltage diodes are connected in parallel.

In FIG. 2, connection conductors 31A, 32A, 33A, 34 made of copper are placed on a container bottom 11 made of, for example, copper via an insulating substrate 2.
A and 31B, 32B, 33B, 34B are fixed. Connection conductor 32A
Above, transistor chips 41A and 41B are respectively connected to diode chips 42A and 42B by collector electrodes on the lower surface.
Are fixed by the cathode electrode on the lower surface, and the constant voltage diode chip 43A is fixed by the anode electrode on the lower surface. For simplicity of illustration, detailed illustration is omitted, but the emitter electrode on the upper surface of the transistor chips 41A and 41B is the connection conductor 31A, the base electrode is the connection conductor 33A, and the anode electrode on the upper surface of the diode chips 42A and 42B is The connection conductor 31A and the cathode electrode on the upper surface of the constant voltage diode chip 43A are connected to the connection conductor 34A by the thin metal wires 5, respectively. Further, on the connection conductor 32B, the transistor chips 41C and 41D are fixed by the lower collector electrode, the diode chips 42C and 42D are fixed by the lower cathode electrode, and the constant voltage diode chip 43B is fixed by the lower anode electrode. Similar to the above, detailed illustration is omitted to make the drawing easy to see, but the emitter electrode on the upper surface of the transistor chips 41C and 41D is the connection conductor 31B, the base electrode is the connection conductor 33B, and the upper surfaces of the diode chips 42C and 42D are The anode electrode of the connection conductor 31B and
The cathode electrode on the upper surface of the constant voltage diode chip 43B is connected to the connection conductor 34B by the thin metal wire 5, respectively. FIG. 1 is a wiring diagram of connection wires between each connection conductor and each external terminal shown in FIG. 2, and external terminals indicated by ◎ in the figure, ie, an emitter (E) terminal, a collector (C) terminal, The base (B) terminal, the cathode (K) terminal, and the control emitter (E) terminal are attached to the upper lid of the transistor module at the upper part of the drawing. The bold dotted line is the connection conductor 8 between the external terminal and each connection conductor. The electrode of each semiconductor chip is connected to each connection conductor. That is, the emitter terminal 61 and each of the transistors 41A, 41B, 41C,
One of the connecting wires connecting 41D is a transistor 41A, 4
The emitter of the connection conductor 31A to which the emitter of 1B is connected is connected to the emitter terminal 61 from almost the midpoint of the connection point of the emitters of the two transistors. Are connected to the emitter terminal 61 from almost the middle of the point where the emitters are connected. In this case, these connection conductors have the same length. In this way, the inductance of the connection conductor from the emitter terminal 61 to each transistor becomes substantially equal. In a similar manner, the collector terminal 62 is between the connection conductors 32A and 32B to which the collector is connected, the base terminal is between the connection conductors 33A and 33B to which the base is connected, and the cathode terminal 64 is the asymmetric element. The connecting conductors 34A and 34B to which the cathodes are connected are connected by connecting wires 8 having the same length. Collector terminal 62, base terminal 63,
As can be seen from the connection conductor of the cathode terminal 64, if the lengths of the two connection conductors are made equal from each other, depending on the positional relationship between the terminal and each connection conductor, the connection conductor may loosen in some cases. As shown in the section P, the connection conductor is held. The details of the portion P are shown in FIG. 3, but the connecting conductor is held by a fastener 9 as shown.

In this embodiment, a control emitter (E) terminal 67 is provided adjacent to the base (B) and the terminal 63 for controlling the transistor, and is connected in the container. Thereby, wiring of the control line outside the transistor module becomes easier.

FIG. 4 is a plan view of a transistor module obtained by assembling a side wall and an upper lid on the container bottom plate 11 shown in FIG. 2, and includes external terminals, that is, an emitter (E) terminal 61, a collector (C) terminal 62, and a base. The positions of the (B) terminal 63, the cathode (K) terminal 64, and the control emitter (E) terminal 67 are the first position.
It corresponds to that in the figure. Capacitor for snubber circuit 7
Is connected between the cathode terminal 64 and the emitter terminal 61.

FIG. 5 is a circuit diagram of the transistor module thus obtained.

〔The invention's effect〕

According to the present invention, in the power conversion device module, when each semiconductor element is connected in parallel, at least the parallel connection includes one in which the same kind of element is fixed on another connection conductor and connected in parallel by a connection conductor. Since the lengths of the connecting wires connected in parallel were made equal and the inductance of this wiring was made equal, loads were equally applied to the elements connected in parallel, up to the rated capacity of each element. It has become fully usable. This increased the output by 5 to 8% compared to the conventional transistor module.

[Brief description of the drawings]

FIG. 1 is a wiring diagram of each semiconductor element connected in parallel and an external terminal in one embodiment of the present invention, FIG. 2 is a plan view showing an arrangement of each semiconductor element and components in the embodiment of FIG. FIG. 3 is an enlarged detailed view of a portion P in FIG. 1, and FIG.
FIG. 5 is a plan view of a transistor module for a power converter according to the present invention assembled on the container bottom plate shown in FIG. 5, FIG. 5 is an equivalent circuit diagram of the transistor module for a power converter shown in FIG. 4, and FIG. FIG. 7 is a perspective view showing the arrangement of elements and components on a container bottom plate in a transistor module for a power converter, FIG. 7 is a perspective view of a conventional transistor module for a power converter assembled on the container bottom plate in FIG. 6, and FIG. FIG. 1 is an equivalent circuit diagram of the conventional transistor module for a power converter shown in FIG. 7, and FIG. 9 is a circuit diagram of a snubber circuit disclosed in Japanese Patent Application No. 1-8311. 41A, 41B, 41C, 41D …… Transistors, 43A, 43B, 43C, 43D…
... constant voltage diode, 61 ... emitter (E) terminal (external terminal), 62 ... collector (C) terminal (external terminal), 63 ...
... Base (B) terminal (external terminal), 64... Cathode (K) terminal (external terminal), 8.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-136412 (JP, A) JP-A-3-108749 (JP, A) JP-A-59-68958 (JP, A) JP-A-61-68 139051 (JP, A) JP-A-2-130954 (JP, A) JP-A-60-151186 (JP, U)

Claims (1)

(57) [Claims] 1. A transistor element accommodated in one container and a forward / reverse asymmetric element having a current / voltage characteristic are fixed on one connection conductor on a container bottom plate with an electrode on one side of each element facing down. The surface-side electrodes are respectively connected to different connection conductors via thin metal wires, and further, these connection conductors and external terminals which are respectively drawn out of the container via the upper lid of the container are connected via connection conductors. In the transistor module for a power conversion device, the transistor element and the asymmetric element each include a plurality of parallel connections, and the parallel connection is such that at least the same type of element is fixed on another connection conductor and the connection is performed in parallel by the connection conductor. A transistor module for a power converter, wherein the connection conductors connected in parallel have substantially the same length. .