JPH05110215A - Power wiring board - Google Patents

Abstract

PURPOSE:To provide a power wiring board which can suppress heat generation at a snubber circuit by making wiring inductance in an inverter device, etc., smaller. CONSTITUTION:A copper foil pattern 7 is connected with copper bars 2A and 2B and they are laid out in parallel. The copper foil pattern 7 is connected with the copper bar 2A.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power wiring board used in an inverter device for driving an AC motor at a variable speed.

[0002]

2. Description of the Related Art In recent years, a power converter such as an inverter device is provided with a wiring for a normal current circuit composed of a printed copper foil pattern and a wiring for a large current circuit composed of a pasted copper bar. The power wiring board which it has is generally used. FIG. 4 is a circuit diagram showing an example of an inverter device using a power wiring board. The converter unit 9 composed of a diode rectifies the AC power supply and smoothes it by the electrolytic capacitor 3 to once make a DC power supply. The DC power supply is converted into AC in the inverter unit 10 composed of an IGBT, a power transistor, etc. to drive and control the motor 11. As is clear from this circuit, the current flowing through the motor 11 is transmitted through the inverter unit 10 to the electrolytic capacitor 3 and the inverter unit 1.
It flows through the DC voltage section between 0, and the DC voltage section has a discontinuous current due to switching of the inverter element (IGBT, power transistor). The DC voltage section has a relatively large wiring inductance 12 due to the physical sizes of the electrolytic capacitor 3 and the inverter element.

When the wiring inductance 12 is included in the path through which the discontinuous current flows, a large surge voltage is generated across the wiring inductance 12. Since this surge voltage is applied to the inverter element, a snubber capacitor 5 which is a snubber circuit is generally provided near the inverter element to prevent the surge voltage from destroying the inverter element. FIG. 2 is a perspective view showing an example of a conventional power wiring board. A copper foil pattern 6 is printed on the surface of the power wiring board 1, and the terminals of the snubber capacitor 5, for example, are connected to the copper foil pattern 6. Copper bars 2A, 2B forming a positive voltage portion and a negative voltage portion of a DC voltage portion are attached to the back surface of the power wiring board 1, and the copper bars 2A, 2B are, for example, electrolytic capacitors 3 and IG.
The terminals of the BT modules 4A, 4B, 4C are connected. This connection is made by screwing a screw 15 penetrating the copper bar 2A into an embedded nut 14 embedded in each terminal as shown in FIG.

[0004]

In the above-mentioned conventional inverter device using the power wiring board, since the wiring inductance is large, the surge voltage generated is also large. Therefore, there is a drawback that the snubber circuit provided for absorbing this surge voltage remarkably generates heat. The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a power wiring board capable of suppressing the heat generation of a snubber circuit by reducing the wiring inductance in an inverter device or the like.

[0005]

According to the present invention, the wiring of a normal current circuit composed of a printed copper foil pattern and one of a positive voltage portion and a negative voltage portion of a DC voltage portion are attached. The present invention relates to a power wiring board having a large current circuit wiring composed of one copper bar and a second copper bar which is adhered and forms the other of the positive voltage portion and the negative voltage portion. The object is achieved by arranging the copper foil pattern and the first and second copper bars so as to be close to and parallel to each other, and connecting the copper foil pattern and the first copper bar. It

[0006]

In the present invention, the wiring of the copper bar connected to the copper foil pattern can be supplementarily connected by another path having a small wiring inductance, so that the discontinuous current flowing in the DC voltage section can be prevented. The high frequency component quickly flows through the copper foil pattern. As a result, most of the current flowing in the snubber circuit will flow into the electrolytic capacitor through the copper foil pattern, and the heat generation of the snubber circuit can be significantly reduced.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an example of a power wiring board according to the present invention.
It is a perspective view shown corresponding to, and the same components are denoted by the same reference numerals and the description thereof is omitted. A copper foil pattern 7 is printed on the surface of the power wiring board 1 so as to overlap the copper bars 2A and 2B. The copper foil pattern 7 and the copper bar 2A are connected by the through holes 13A, 13B, 13C and 13D formed in the copper foil pattern 7 portion. On the back surface of the power wiring board 1, a back surface copper foil pattern 8 to which one terminal of the snubber capacitor 5 is connected is printed. In this way, the copper foil pattern 7 and the copper bar 2A,
2B is close and parallel to the copper foil pattern 7
Since the wiring circuit of the DC voltage section is constituted by the copper bars 2A and 2B, the wiring inductance can be made extremely small. Although the capacitor is used as the snubber circuit in this embodiment, the same effect can be obtained even if the snubber circuit is a combination of a capacitor and a diode or a resistor.

[0008]

As described above, according to the power wiring board of the present invention, the heat generation of the snubber circuit in the inverter device or the like can be greatly reduced, so that the switching frequency can be reduced by the snubber circuit which is simpler and cheaper than the conventional one. It is possible to realize higher frequency.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example of a power wiring board of the present invention.

FIG. 2 is a perspective view showing an example of a conventional power wiring board.

FIG. 3 is a cross-sectional view showing an example of a wiring connection portion of a power wiring board.

FIG. 4 is a circuit diagram showing an example of an inverter device using a power wiring board.

[Explanation of symbols]

 1 Power wiring board 2A, 2B Copper bar 6, 7, 8 Copper foil pattern

Claims (2)

[Claims] 1. A wire for a normal current circuit composed of a printed copper foil pattern, a first copper bar attached to form one of a positive voltage portion and a negative voltage portion of a DC voltage portion, and the positive voltage. Part or a negative voltage part, the power wiring board having a wiring of a large current circuit composed of the adhered second copper bar which forms the other of the copper foil pattern and the first and second copper bars. Are arranged so as to be close to and parallel to each other, and the copper foil pattern and the first copper bar are connected to each other. 2. The power wiring board according to claim 1, wherein the copper foil pattern and the first and second copper bars are arranged so as to overlap with the front and back of the board.