JPH09117126A - Power converter - Google Patents

Abstract

(57) Abstract: In a power conversion device, a plurality of semiconductor switching elements, a smoothing capacitor, and a DC bus of positive and negative electrodes and an output bar are arranged, so that a current sharing occurring in the semiconductor switching element or the smoothing capacitor is uneven. To correct. SOLUTION: Positive and negative DC busbars 3 and 4 connected from a smoothing capacitor 2 to a semiconductor switch element 1 are arranged in a laminated manner with an insulating material 8 interposed therebetween. Further, the output terminals of the plurality of semiconductor switching elements 1 are short-circuited to form a tournament-shaped output bar 5 for each phase connected to the output terminal block, and a square hole is provided at the center.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power converter, and more particularly to arrangement of parts and structure of busbars.

[0002]

2. Description of the Related Art FIG. 4 is a front view showing the structure of a conventional example. In FIG. 4, the semiconductor switch element 1 is arranged on the upper side, and the smoothing capacitor 2 is arranged on the lower side thereof.
In order to simplify the shape of the bus bar, the () terminal is placed with the (+) terminal facing up and the (-) terminal facing down, and the electrolytic solution enclosed in the smoothing capacitor may change due to a chemical change or temperature rise. The position of the explosion-proof valve 6 that releases this internal pressure when it vaporizes and becomes gas and the internal pressure rises is on the left side.

A positive electrode direct current bus bar 10 is provided which collects the (+) terminals of the smoothing capacitor 2, and the positive electrode direct current bus line 10 and the semiconductor switch element 1 are connected by a (+) bar 10A. Similarly, a negative electrode DC bus line 11 that collectively includes (-) terminals is provided, and the negative electrode DC bus line 11 and the semiconductor switch element 1 are connected by a (-) bar 11A. FIG. 5 is a perspective view of a conventional output bar. In FIG. 5, the output bar 12 is pulled out from the center of the short-circuit bar 12A in which the output terminals of the semiconductor switch elements 1 of the respective phases are short-circuited. In this case, the wiring distance from each output terminal of the semiconductor switching element 1 to the output bar 12 is not uniform between the semiconductor switching element located far from the output bar 12 and the semiconductor switching element located close to it.

[0004]

In such a conventional structure, since the explosion-proof valve 6 of the smoothing capacitor 2 is not located on the upper side, the resin fixing the electrodes inside the smoothing capacitor settles down. There is a problem that the explosion-proof valve 6 is easily clogged. In recent years, power conversion devices that use IGBTs (insulated gate bipolar transistors) for semiconductor switching elements have been increasing along with the speeding up of switches.

In such a power converter, the time interval for switching on / off of the semiconductor switching element becomes short,
The nonuniform wiring distance, that is, the nonuniform wiring inductance greatly affects the current sharing of the semiconductor switch element. When imbalance occurs in the current sharing of the semiconductor switch element,
Since the breakdown of the element due to overcurrent is promoted, the rating of the semiconductor switching element and the snubber circuit capacity are increased, which in turn increases the cost and the size of the device. Further, the wiring inductance of the snubber capacitor may cause a voltage jump at the time of switching and an overvoltage may be applied to the semiconductor switch element.

Therefore, an object of the present invention is to make the wiring inductance uniform and reduce its value to prevent an increase in the rating of the semiconductor switch element and the snubber circuit capacity, thereby reducing the cost and downsizing the device. An object of the present invention is to provide a power conversion device capable of performing the above.

[0007]

In order to achieve the above-mentioned object, the present invention provides a plurality of semiconductor switching elements, a snubber capacitor connected to these semiconductor switching elements, and a smoothing power source on a cooling body. In a power converter in which at least a capacitor and positive and negative DC buses connected to the smoothing capacitor are arranged, positive and negative DC buses connected from the smoothing capacitor to the semiconductor switch element are laminated via an insulating material. Is located on the left side of the smoothing capacitor terminal when viewed from the front,
With the (+) terminal on the right side, arrange the explosion-proof valve facing upwards, which releases the internal pressure of the smoothing capacitor when it rises.

Further, the output terminals of a plurality of semiconductor switching elements are short-circuited to form a tournament-shaped output bar for each phase connected to the output terminal block, and a square hole is provided in the central portion. According to the configuration of the present invention, the positive and negative DC bus lines connected from the smoothing capacitor to the semiconductor switching element are arranged in a laminated manner with the insulating material interposed between them so that the explosion-proof valve of the smoothing capacitor is directed upward. Therefore, the clogging of the explosion-proof valve can be largely eliminated.

Further, since the area of the portion where the positive electrode DC busbar and the negative electrode DC busbar are close to each other can be increased,
The heat dissipation area increases, the heat inside the smoothing capacitor is dissipated through the terminals, and the temperature rise is suppressed, and the wiring inductance between the smoothing capacitor and each semiconductor switch element decreases. Further, the output bar of each phase is formed into a tournament shape, and a square hole is provided in the central portion to improve the balance of current sharing among the semiconductor switch elements.

Further, the balance resistor can be modularized structurally, and wiring can be eliminated.

[0011]

1 is a front view showing an embodiment of the present invention, and FIG. 2 is a detailed perspective view of a smoothing capacitor 2 arranged in the upper portion of FIG. In FIG. 1 and FIG. 2, in this embodiment, two smoothing capacitors 2 connected in parallel are two.
A total of 12 terminals are arranged in series, with the terminal surface facing the front side, and mounted on the smoothing capacitor mounting plate 13. Further, the terminals of the smoothing capacitor 2 are arranged so that the left side is the (-) terminal and the right side is the (+) terminal, and the explosion-proof valve 6 is directed to the upper side.

On the terminal surface of the smoothing capacitor 2, a positive electrode DC busbar 3 and a negative electrode DC busbar 4 are insulated via an insulating material 8 and assembled in a laminated form. Reference numeral 9 is a positive / negative short-circuit bar for connecting the smoothing capacitors 2 in two stages in series. Reference numeral 7 is a modularized balance resistor. Two cooling fans 20 for cooling the smoothing capacitor 2 are attached to the smoothing capacitor mounting plate 13 by cooling fan fixing plates 16, 18, and 19. Reference numeral 17 is a condenser for the cooling fan 20.

The ventilation airflow generated by the operation of the cooling fan 20 is partitioned by a partition plate 15, and a thermal guard 14 is provided in each ventilation passage to detect when one of the cooling fans 20 is stopped. Has been. Below the smoothing capacitor 2, a plurality of semiconductor switch elements 1 mounted on the cooling body are arranged, and the output terminals of each phase are connected by short-circuiting the output terminals of the semiconductor switch elements 1 to the output terminal block of the device. Are arranged.

FIG. 3 is a perspective view showing the output bar of the embodiment of the present invention. In FIG. 3, by providing a square hole 5A at the center of the tournament-shaped output bar 5, the direction of the current becomes as shown by the arrow in FIG. 3, and by appropriately determining the size of the square hole 5A, each semiconductor It is possible to make the current sharing of the switch element almost uniform.

[0015]

According to the present invention, the wiring inductance is made uniform and the value itself is made small to prevent the rating of the semiconductor switching element and the snubber circuit capacity from increasing, thereby reducing the cost and downsizing the device. A power converter that can be achieved is obtained.

[Brief description of the drawings]

FIG. 1 is a front view showing an embodiment of the present invention.

FIG. 2 is a detailed perspective view of a smoothing capacitor arranged in the upper part of FIG.

FIG. 3 is a perspective view showing an output bar according to an embodiment of the present invention.

FIG. 4 is a front view showing a configuration of a conventional example.

FIG. 5 is a perspective view of a conventional output bar.

[Explanation of symbols]

 1 Semiconductor Switching Element 2 Smoothing Capacitor 3 Positive DC Bus Bus 4 Negative DC Bus 5 Output Bar 5A Square Hole 6 Explosion-proof Valve 7 Balance Resistance 8 Insulation Material 9 Positive / Negative Shorting Bar 13 Smoothing Capacitor Mounting Plate 14 Thermal Guard 15 Partition Plate 16 Cooling Fan Fixing Plate 17 Cooling Fan Capacitor 18 Cooling Fan Fixing Plate 19 Cooling Fan Fixing Plate 20 Cooling Fan

Claims (3)

[Claims] 1. A plurality of semiconductor switching elements, a snubber capacitor connected to these semiconductor switching elements, a smoothing capacitor serving as a power source, and positive and negative DC busbars connected to the smoothing capacitor on a cooling body. In the power conversion device in which at least are arranged, the positive and negative DC busbars connected from the smoothing capacitor to the semiconductor switch element are arranged in a laminated manner with an insulating material interposed therebetween. 2. The device according to claim 1, wherein the terminal of the smoothing capacitor is viewed from the front (-) terminal on the left side and (+)
An electric power converter characterized in that an explosion-proof valve for escaping the internal pressure of the smoothing capacitor when the internal pressure of the smoothing capacitor rises with the terminal on the right side is arranged facing upward. 3. The shape of the output bar for each phase connected to the output terminal block by short-circuiting the output terminals of the plurality of semiconductor switch elements in the central part as a tournament according to claim 1. An electric power converter having a square hole.