JPH1098885A - Inverter device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inverter device which can reduce the inductance of a DC bus or wiring and suppress switching surge voltage from increasing in the structure of this device. SOLUTION: Cooling fins on which switching elements 5 comprising inverters are fitted at their upper parts are disposed in a plurality of rows, and a smoothing capacitor 3 is disposed between the rows. The switching element 5 and the smoothing capacitor 3 are connected to each other through a plate- shaped conductor 6. Cooling fins on which the switching elements 5 comprising inverters are fitted at their side parts are disposed in a plurality of rows so that the switching elements 5 may face, and smoothing capacitors 3 are disposed under respective rows. The switching element 5 and the smoothing capacitor 3 are connected to each other through a plate-shaped conductor 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inverter device used for driving an electric motor and the like, and to a spatial arrangement of a switching element and a smoothing capacitor for reducing a switching surge of a switching element constituting an inverter. .

2. Description of the Related Art The wiring of an inverter device is generally as shown in FIG. Reference numeral 1 denotes a forward converter for converting AC power into DC, and reference numerals 2 and 3 denote a smoothing reactor and a smoothing capacitor for smoothing the DC output of the forward converter 1. Reference numeral 4 denotes an inverter for converting the DC output into an AC output, and is composed of a plurality of switching elements 5. The switching element 5 is divided into an upper phase and a lower phase, and an AC output is obtained between the upper phase and the lower phase. The smoothing reactor 2, the smoothing capacitor 3 and the inverter 4 are connected by a DC bus 6. The smoothing capacitor 3 is similarly divided into an upper phase and a lower phase. In recent inverter devices, an IGBT (isolated) is used as the switching element 5 in accordance with a higher carrier frequency.
-Gate bipolar transistor)
High-speed switching using such as is increasing. When the switching element 5 performs high-speed switching, the anode-
The switching surge voltage generated between the cathodes and between the collector and the emitter in the case of the IGBT increases, which causes the switching element 5 to be destroyed. The magnitude of the switching surge voltage is proportional to the inductance of the DC bus 6 and the wiring between the switching elements. Therefore, a technique for reducing this inductance is disclosed in
This is disclosed in JP-A-91268 and JP-A-8-11068. However, the wiring structures described in these publications are planar or two-dimensional, and are not sufficient to reduce inductance in an actual inverter device.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an inverter device capable of reducing the inductance of a DC bus or wiring and reducing the switching surge voltage in the configuration of an actual machine.

In order to achieve the above object, an inverter device according to a first aspect of the present invention comprises a plurality of cooling fins having switching elements constituting an invertor mounted thereon, the cooling fins being arranged in a plurality of rows. A smooth gondenser is arranged between rows, and the switching element and the smoothing capacitor are connected by a plate conductor. In the second invention, cooling fins having switching elements constituting the inverter attached to side portions are arranged in a plurality of rows so that the switching elements face each other, and a smoothing capacitor is arranged below each row, The switching element and the smoothing capacitor are connected by a plate-like conductor. With such a configuration, since the smoothing capacitor and the switching element are arranged three-dimensionally, the wiring between them can be shortened, and the inductance can be reduced by the shape effect of the plate-shaped conductor.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIGS. As shown in these figures, the smoothing capacitor 3 is arranged between the cooling fins to which the upper-phase switching element and the lower-phase switching element 5 are attached, and between the switching elements 5, between the switching element 5 and the smoothing capacitor 3, and between the switching elements 5. The capacitors 3 are connected to each other by the plate-shaped conductor 6. The connection from the switching element 5 to the AC output terminal 7 is also a plate conductor. By arranging the smoothing capacitor 3 in the center as described above, the power supply fluctuation caused by the load fluctuation is absorbed by the smoothing capacitor 3 and the voltage drop generated in the smoothing capacitor 3 is small because the impedance to the switching element 5 is small. Anything beyond that is transmitted to the switching element 5 without amplification. That is, the switching surge applied to the switching element 5 is only the surge generated by the switching element 5 itself, and the superimposition of the power supply vibration is only the rebound of the potential drop due to the smoothing capacitor 3, and the surge snubber circuit can be reduced. . By adopting the plate-shaped conductor 6, arranging the switching elements 5 uniformly, and making the input / output reverse structure in the capacitor input section, the current of the smoothing capacitor 3 can be equalized. By arranging the gate terminal of the switching element 5 at the center of the element, a single structure can be used for the upper and lower phase switching elements, so that the switching elements can be unified. In addition, since the wiring of the inverter device according to the present embodiment is simple, it is easy to assemble and downsize. Next, a second embodiment of the present invention will be described with reference to FIGS. As shown in these figures, cooling fins having switching elements 5 attached to the sides are arranged in a plurality of rows so that switching elements 5 face each other, and smoothing capacitors 3 are arranged below each row. And the smoothing capacitor 3 is connected by a plate-shaped conductor 6. When the smoothing capacitor 3 is arranged under the switching element 5 in this manner, the distance between the smoothing capacitor 3 and the switching element 5 becomes short, and the reactance can be reduced. Easy to repair. Also, because of the two-layer structure,
This is advantageous not only for the heat generation of the switching element 5, but also for the advantage that the fin cooling air can be used for cooling the condenser.

According to the inverter device of the present invention, since the switching element and the smoothing capacitor can be arranged three-dimensionally, the inductance of the DC bus and the wiring can be reduced, and the switching surge voltage can be reduced.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an inverter device according to a first embodiment of the present invention.

FIG. 2 is a top view of FIG.

FIG. 3 is a configuration diagram of an inverter device according to a second embodiment of the present invention.

FIG. 4 is a top view of FIG. 3;

FIG. 5 is a wiring diagram of a general inverter device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Forward converter, 2 ... Smoothing reactor, 3 ... Smoothing capacitor, 4 ... Inverter, 5 ... Switching element, 6 ...
DC bus, 7 ... AC output terminal.

Claims (2)

[Claims] 1. A cooling fin having a switching element constituting an inverter mounted thereon is arranged in a plurality of rows, a smoothing capacitor is arranged between the rows, and a plate-like conductor is provided between the switching element and the smoothing capacitor. An inverter device comprising a configuration connected by: 2. Cooling fins having switching elements constituting an inverter mounted on side portions thereof are arranged in a plurality of rows so that the switching elements face each other, and a smoothing capacitor is arranged below each row, and An inverter device comprising a configuration in which an element and a smoothing capacitor are connected by a plate-shaped conductor.