JPS60200560A - Parallel connecting structure of transistor module - Google Patents

Abstract

PURPOSE:To minimize a surge voltage at OFF time by forming a balance type parallel conductor structure symmetrical at the right and left sides with a power supplying point as a fulcrum in a main circuit conductor, thereby holding the optimum balance in a main circuit current. CONSTITUTION:Main circuit conductors 2a-2c formed in a balance type symmetrical at the right and left sides with a power supplying point 3a as a fulcrum are formed at the minimum distance from an AC terminal, an N terminal and a P terminal of power receiving point of transistor modules 1a-1f, of plate- shaped parallel conductors, and interposed in contact with an insulator 56 therebetween. A main circuit current from a power source is supplied through lead wirings 4a-4c, from power supplying points 3a-3c to transistor modules 1a-1f through main circuit conductors 2a-2c at equal distance to AC terminal, N terminal and P terminal of power receiving points of the modules 1a-1f. This is performed by forming symmetrical in balance at the right and left sides with the power supply point as a center at the conductors 2a-2c.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a transistor module that can supply main circuit current in an optimal balance to a plurality of transistor modules in power equipment. This relates to parallel connection structures.

[Prior art]

Conventionally, there has been a parallel connection structure of this type of transistor module as shown in FIG. 1(a).

In the circuit voltage, 1 is 6 of transistor modules 1a to 1f.
This is a transistor module group in which modules are assembled, and each has an AC terminal, an N terminal, and a P terminal as power receiving points. 2a to 2C are each of the above transistor modules 1
It is a main circuit conductor such as a bus bar or electric wire that connects each terminal of a to 1f, respectively, and is connected to the above power receiving point, and in the case of the figure, it is the AC terminal, N terminal, and P terminal of transistor module 1a. The terminals serve as power feeding points 3a, 3b, and 3c from a power supply device (not shown), respectively. 4a to 4C are lead wires connecting the main circuit conductors 23 to 2C and the power supply device,
It is connected to a power feeding point via main circuit conductors 2a to 2C with screws or the like. FIG. 1(b) shows a side view of FIG. 1(a), and in the figure, 5 is a nine-in-one module group (
This is a heat dissipation fin for 1). FIG. 2 is a circuit diagram showing a conventional parallel connection structure having the above configuration, and in the figure, the same reference numerals as in FIG. 1 indicate the same elements.

Next, the operation of the parallel connection structure having the above configuration will be explained.

In FIG. 1, the conductor distances from the power feeding point 3a to each AC terminal, which is the power receiving point of each transistor module 1a to 1f, are different from each other.

The same applies to 3C. Therefore, as shown in FIG. 2, the impedance difference between the transistor modules 1a to 1f as seen from the feed points 3a, 3b, and 3c is very large.
Each main circuit current becomes unbalanced. That is, a large main circuit current flows through the transistor module 1a, and a small main circuit current flows through the transistor module 1f, causing an imbalance in each of the transistor modules 18 to 1f.

Further, due to the floating inductance of the main circuit conductors 2a to 2C, the transistor module 1f that is farthest from the feeding point 1a has a particularly large floating inductance.

Since the conventional parallel connection structure of transistor modules is configured as described above, there is a large impedance difference between each transistor module, and the transistor module at the far end from the feed point has a large stray inductance, so the main circuit at turn-on is There were drawbacks such as a large current imbalance, and a large surge voltage when off due to a load short circuit that could destroy the transistor.

[Summary of the invention]

This invention was made in order to eliminate the drawbacks of the conventional ones as described above, and the main circuit conductor is made into a horizontally symmetrical parallel conductor structure with the feeding point as the fulcrum to maintain the main circuit current in an optimal balance. The purpose of this invention is to provide a parallel connection structure of transistor modules that can minimize surge voltage when off.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described based on FIGS. 3fa) and 3(b).

Figure 3(a) shows the parallel connection structure of the present invention, and Figure 3(a) shows the parallel connection structure of the present invention.
B) shows the side view of Fig. 21. Fig. 4 is the circuit diagram of Fig. 3 (→, (b)).
b) The same reference numerals as in FIG. 2 indicate the same elements. Third
In the figure (→, (b), 28 to 2C are main circuit conductors formed in a symmetrical balance shape with the power feeding point 3a as the fulcrum, and the AC terminal and N terminal are the power receiving points of each transistor module 1a to lf. , P terminals, respectively.The main circuit conductors 23-2C are connected to the AC terminals, N terminals, and P terminals of each transistor module 1a-1f by screws or the like. Further, each of the main circuit conductors 2a to 2C is a plate-shaped parallel conductor, and an insulator 6 is closely interposed between them.

Next, the operation of the embodiment having the above configuration will be explained.

In FIG. 3 (Chorus, tb>), the main circuit current from the power supply device (not shown) is supplied to the transistor modules 13 to 1f via the leads +1J4a to 4c at power supply points 3a to 3.
Power is supplied from C through each main circuit conductor 28 to 2C to each AC terminal, N terminal, and P terminal, which are power receiving points of each transistor module 1a to 1f, at equal distances from each other. This has been made possible by forming the main circuit conductors 23 to 2C in a balance shape that is completely symmetrical left and right with respect to the feed point.

Therefore, the same main circuit current flows from the power supply points 3a to 3C to the power receiving points of each transistor module 1a to If.
The impedances seen from the feed points 3a to 3c are the same as shown in FIG. 4, and it is possible to minimize the impedance difference between each transistor module.

At the same time, each main circuit conductor of 2a to 2C is arranged in parallel,
Since the insulator is interposed between each of the main circuit conductors 2a to 20, it acts to cancel out stray inductance.

〔Effect of the invention〕

As described above, according to the present invention, the main circuit conductor is formed in a symmetrical balance shape from the power supply point, so that an equal main circuit current can flow to each transistor module, and the main circuit conductor at turn-on can be This has the effect of providing a highly reliable parallel connection structure of transistor modules in which the current is optimally balanced and the OFF voltage in the event of a load short circuit is minimized.

[Brief explanation of drawings]

FIG. 1(a) is a structural diagram showing a parallel connection structure of a conventional transistor module, FIG. 1(b) is a side view of the same, FIG. 2 is a circuit diagram of the same, and FIG. A structural diagram showing a parallel connection structure of transistor modules according to an embodiment,
FIG. 3(b) is a side view of the same, and FIG. 4 is a circuit diagram of the same. 1a to 1f...transistor module, 23 to 2C
...Main circuit conductor, 38~3C...Feeding point, 6...
Insulator. In addition, in the figures, the same reference numerals indicate the same or equivalent parts. Patent applicant Mitsubishi Electric Corporation

Claims (1)

[Claims] In a power device such as an inverter using a plurality of transistor modules, a plurality of conductors, which are power supply paths for the plurality of transistor modules, are formed in a symmetrical balance shape with the power supply point as a fulcrum, and from the tip of the pole of the balance to the above-mentioned conductors. The main circuit conductor is shaped so that the distance to the power receiving point of each transistor module is the shortest, and the main circuit conductors are arranged parallel to each other with an insulator interposed between the plurality of conductors. Parallel connection structure of transistor modules.