Electric power conversion/inversion apparatus

Electric power conversion systems – Current conversion – With conductive support mounting

Reexamination Certificate

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Details

C361S689000, C361S688000

Reexamination Certificate

active

06618278

ABSTRACT:

BACKGROUND OF THE INVENTION
The present invention relates to an electric power conversion/inversion apparatus, such as, an inverter, etc., and in particular to an electric power conversion/inversion apparatus, being used as a motor driving apparatus for use in an automobile, upon which a high reliability is required.
An inverter according to the conventional art
1
, as was shown by a third embodiment in Japanese Patent Laying-Open No. Hei 11-346480 (1999), comprises: two power supply bus bars for inputting DC electric power from a DC power source and a capacitor; a plural number of output bus bars for outputting three-phase AC electric power to a motor; a plural number of semiconductor switching modules, being electrically connected to those power supply bus bars and the output bus bars, for inverting the DC electric power inputted into the three-phase AC electric power, to be outputted; and a heat sink on which are mounted those semiconductor switching modules, the power supply bus bars and the output bus bars.
Explanation will be given on that inverter apparatus according to the conventional art
1
, in more details thereof. The plural number of the power supply bus bars comprises a positive (+) power supply bus bar and a negative (−) power supply bus bar. The plural number of the output bus bars is provided in number of three (3), so as to form three-phase thereby. The semiconductor module comprises three (3) parallel circuits, in each of which an IGBT and the reverse-parallel diode are connected, thereby forming each of the arms of a three-phase inverter. One of the phases of the three-phase bridge is formed with two (2) of the arms, and semiconductor modules constructing those two arms are provided on the heat sink through an insulator substrate, a common electrode pattern, and a high temperature soldering, so as to be disposed in parallel at both sides thereof. The output bus bars and the positive (+) power supply bus bar are provided on the heat sink, surrounding the semiconductor switching modules provided in parallel, through a insulator plate with contacting therewith. Furthermore, the negative (−) power supply bus bar is provided on the output bus bars through a insulator plate, with contacting therewith. Also, the negative (−) power supply bus bar is disposed, so as to be located in a middle of the semiconductor switching modules provided in parallel. And, the output bus bars or the power supply bus bars and the semiconductor switching modules are connected therebetween through a wire bonding.
Further, in the inverter apparatus of this conventional art
1
, the semiconductor switching modules forming an inverter main circuit and the bus bars are attached on the surface of the heat sink, to be contacted with, while a cooling water path is formed on the reverse surface thereof, to cool it, thereby obtaining small-sizing and a long life-time of the inverter apparatus for an electric car.
Also, the semiconductor apparatus having the semiconductor switching elements therein, according to a conventional art
2
, as shown in Japanese Patent Laying-Open No. 2000-49281, comprises: a pair of semiconductor switching elements, each having a positive electrode on one surface thereof while a negative one on the other surface; a circuit board, on which the pair of the semiconductor switching elements are mounted in different directions from each other, having a common land on which the positive electrode of one of the semiconductor switching elements and the negative electrode of the other semiconductor switching element are connected by soldering; and a wiring being positioned above the common land and extending in parallel thereto, on which the negative electrode of the one semiconductor switching elements and the positive electrode of the other semiconductor switching element are connected by soldering.
The semiconductor apparatus according to this conventional art
2
is provided for the purpose of eliminating a wiring of a shape “L” therefrom, having a component or portion extending in an orthogonal direction to the substrate, thereby to prevent inductance and/or wiring resistance from being increased due to the same wiring in the orthogonal direction to the substrate, as well as obtaining small-sizing of a package by narrowing the distance between the semiconductor switching elements.
However, with the conventional art
1
, the output bus bars and the positive (+) power supply bus bar are provided surrounding the semiconductor switching modules provided in parallel, while the negative (−) power supply bus bar in the middle of the semiconductor switching modules provided in parallel, therefore a plane space of the semiconductor apparatus as a whole comes to be a total of each plane area of the semiconductor switching modules, the output bus bars, and the positive (+) and the negative (−) power supply bus bars, or more. This brings about a problem, in particular in a case where it is applied or used as the electric power inverter for use in an automobile, since the space where it is installed is very restrictive.
Also, according to the conventional art
1
, the semiconductor switching modules provided in parallel and the output bus bars which is provided therealong or the power supply bus bars are connected there between by the wire bonding, therefore the wiring as a whole comes to be complex, thereby increasing the circuit inductance and the wiring resistance thereof.
Furthermore, according to the conventional art
1
, since heat is radiated from the heat sink on one side of the semiconductor switching modules, the cooling of the semiconductor switching modules as a whole must be done by an amount of heat radiation through the heat sink on that one side thereof, therefore there is a problem that the heat radiation cannot be obtained with certainty. Moreover, since the semiconductor switching modules are provided on the common electrodes only through the soldering, and since, generally the semiconductor switching modules and the electrodes are different greatly in the linear expansion coefficient thereof, there is a problem that the soldering receives a large thermal fatigue from thermal cycles due to the intermittent ON-OFF operation of the semiconductor switching modules.
On a while, according to the conventional art
2
, there is no description about the detailed construction for obtaining the small-sizing of the inverter apparatus as a whole, but the semiconductor switching elements and the land or the wiring are contacted only through the soldering, there is also a problem that the soldering receives a large thermal fatigue from thermal cycles due to the intermittent ON-OFF operation of the semiconductor switching elements.
SUMMARY OF THE INVENTION
An object, according to the present invention, is to provide an electric power conversion/inversion apparatus, achieving reduction in the circuit inductance and the wiring resistance thereof, while bringing the apparatus to be compact in sized as a whole, thereby obtaining an electric conversion/inversion apparatus having a good installation, as well as a high reliability and an efficiency in the electric power conversion/inversion.
Other object, according to the present invention, is to provide an electric power conversion/inversion apparatus, achieving reduction in the circuit inductance and the wiring resistance thereof, and also mitigating the thermal fatigue against the thermal cycles, while bringing the apparatus to be compact in sizes as a whole, thereby obtaining an electric conversion/inversion apparatus having a good installation, as well as a high reliability and an efficiency in the electric power conversion/inversion.
Further other object, according to the present invention, is to provide an electric power conversion/inversion apparatus, achieving reduction in the circuit inductance and the wiring resistance thereof, and also protecting the electrode surfaces of the semiconductor chips from deterioration due to elapse of time, while thereby obtaining an electric

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