JPH0578196U - Power conversion unit - Google Patents

Abstract

(57) [Abstract] [Purpose] Easy to assemble, maintain and inspect, and prevent the life from shortening due to current imbalance of switching elements. [Structure] A plurality of IGBTs 1A are mounted on both sides of the heat sink 2 in the front-back direction with the collector electrode C side facing up.
The same number of IGBTs 1B as the upper stage are attached to the lower stages of both sides of the heat sink 2 with the collector electrode C side facing upward. The collector electrode of the upper IGBT 1A is the positive electrode side conductor 3A.
Then, the emitter electrode E of the lower-stage IGBT 1B is connected by the positive electrode side conductor 3B and is connected to the positive electrode side input terminals 5A, 5B in front of the unit frame 8. The emitter electrode E of the IGBT 1A and the collector electrode C of the IGBT 1B are connected by the AC side conductor 4, and the female disconnection portions 7A, 7B at the rear portion of the unit frame 8 are connected.
Connect with.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a power conversion unit, and more particularly to a power conversion unit in which a plurality of switching elements are connected in parallel by conductors.

[0002]

[Prior Art]

 FIG. 4 is a perspective view showing a conventional power conversion unit for a one-phase circuit incorporated in the inverse conversion device, and FIG. 5 is a view taken in the direction of arrow B in FIG.

In FIGS. 4 and 5, a heat sink 1 is erected at the center of the inside of the unit frame 8. The heat sink 1 has an insulated gate on the upper side on the arrow B side in FIG. 4 (hereinafter referred to as the left side surface). Three bipolar transistors (hereinafter referred to as IGBTs) 1A are mounted side by side in a row with the collector electrode C side facing upward. Below the IGBT1A, three IGBT1B having the same shape as that of the IGBT1A are similarly mounted with the collector electrode C side facing upward. Similarly, on the left rear side (hereinafter, referred to as the right side surface) of the heat sink 1 in FIG. 4, the same shape IGBT1A faces the collector electrode C side at the position on the back side of the mounting surface of each left IGBT1A. The IGBTs 1B having the same shape are also mounted in a row on the lower side of these IGBTs 1A at the position on the back side of the mounting surface of the left IGBT 1B, with the collector electrode C side facing upward.

Of these, the collector electrodes C of the upper IGBT 1A are connected to the long side portions of the strip plate-shaped positive electrode side conductors 3A bent in a substantially L shape, and these positive electrode side conductors 3A have short ends (not shown). A pair of positive-electrode-side input conductors 5A, which are bent in an L shape and whose front ends protrude in the front direction of the unit, are connected to the ends of the sides (hereinafter referred to as front ends). Similarly, the respective emitter electrodes E of the lower IGBT 3B are connected to the long side portions of the same negative electrode side conductor 3B as the positive electrode side conductor 3A, respectively, and the tips of the short side portions (not shown) of these negative electrode side conductors 3B are connected. The rear end of the negative electrode side input terminal 5B, which is the same product as the positive electrode side input terminal 5A, is connected to.

On the other hand, the emitter electrode E of the IGBT 1A and the collector electrode C of the IGBT 1B are a strip-shaped AC side conductor 14 having a width twice that of the positive electrode side conductor 3A and the negative electrode side conductor 3B, which are bent in the same L shape. Of the AC side conductors 14 are connected to each other at their long sides, and the front ends of the short sides of the AC side conductors 14 are also bent in the L shape, and the front ends of the AC side conductors 14 project toward the front of the unit. Are connected respectively.

A cover (not shown) is attached to the outer periphery of the unit frame 8. Of these, an exhaust fan 9 is attached to the lower surface of the central portion of an upper cover (not shown), and a lower side cover (not shown) is attached. An air filter (not shown) is detachably attached.

In the power conversion unit configured as described above, at least three units are incorporated in the power conversion device, and in each unit, the positive side input terminal 5A and the negative side input terminal 5B at the front end are not shown. The AC output terminal 6 is connected to a DC power source, and is connected to a load such as a transformer (not shown). Therefore, the work of connecting the positive side input terminal 5A, the negative side input terminal 5B and the AC side output terminal 6 is performed from the front surface of each unit.

[0008]

[Problems to be solved by the device]

 However, in the power conversion unit having such a configuration, the IGBTs 1A and 1B arranged in the front and rear and connected by the positive electrode side conductor 3A, the negative electrode side conductor 3B and the AC side conductor 14 are located at the rear side. The IGBTs 1A, 1B that are arranged in front of the IGBTs 1A, 1B have longer electric paths to the positive side input terminal 5A, the negative side input terminal 5B, and the AC side terminal 6 than the front IGBTs 1A, 1B. As a result, the energization current decreases, and conversely the energization current of the IGBTs 1A and 1B at the front end increases, so the temperature rises and the life is impaired.

Further, the work of connecting a flexible conductor or a cable or a bus to the positive electrode side input terminal 5A, the negative electrode side input terminal 5B and the alternating current side output terminal 6 is performed by connecting these conductors connected to an adjacent terminal or an upper unit. It is complicated and difficult to do, and it takes time. Therefore, an object of the present invention is to obtain a power conversion unit that is easy to assemble and maintain and that can prevent the life of the switching element from being shortened due to current imbalance.

[0010]

[Means for Solving the Problems]

 According to the present invention, a plurality of switching elements are attached to the upper and lower tiers on both sides of a heat sink housed in a unit with the polarities of the upper and lower terminals in the same direction. The lower terminals of the switching element are connected to each other by a DC conductor with an input terminal at the front of the unit, and the lower terminal of the upper switching element and the upper terminal of the lower switching element are connected by a common AC conductor. In the power conversion unit described above, a disconnecting portion connected to the rear end of the AC side conductor is provided at the rear portion of the unit.

[0011]

[Action]

 The length of the electric path from the input terminal to the rear end of the AC side conductor through the DC side conductor and each switching element is the same length between the electric paths that pass through each switching element, and external connection work is performed only at the input terminal. Become.

[0012]

【Example】

 An embodiment of the power conversion unit of the present invention will be described below with reference to the drawings. However, the same parts as those in FIGS. 4 and 5 are designated by the same reference numerals and the description thereof will be omitted. FIG. 1 is a perspective view showing a power conversion unit of the present invention, a view corresponding to the conventional FIG. 4, FIG. 2 is a view taken along the arrow A in FIG. 1 and corresponding to FIG. 5, and FIG. It is a connection diagram of a power conversion unit of the invention.

In FIGS. 1, 2 and 3, the collector electrodes C of the IGBT 1A mounted on both upper surfaces of the heat sink 2 are connected to each other at the long sides of the L-shaped positive electrode side conductor 3A which is the same as the conventional one. Similarly, the emitter electrodes E of the IGBTs 1B attached to both lower surfaces of the heat sink 2 are also connected by the same negative electrode side conductor 3B as the conventional one.

On the other hand, the emitter electrode E of the IGBT 1A and the collector electrode C of the IGBT 1B have the same strip plate and the same shape as the conventional AC side conductor 14, but the long side of the AC side conductor 4 has a slightly longer rear portion. The sides are similarly connected. (Note: in FIG. 1, the widths of the strips of the positive electrode side conductor 3A and the negative electrode side conductor 3B and the alternating current side conductor 4 are about three times different, but in actuality, as in the conventional case shown in FIG. : The ratio is 2.) The lower ends of the rear ends of the AC side conductors 4 are connected to the upper ends of strip-shaped connecting conductors 15 standing upright at the rear ends of the unit frames 8 by bolts. .

A terminal block 11 made of epoxy resin is laterally fixed to the rear end of the lower part of the unit frame 8, and a pair of through conductors 16 made of strip copper material are previously embedded in the terminal block 11. At the rear end of the penetrating conductor 16 that is inserted and protrudes from the rear surface of the terminal block 11, there are tulip connection type female disconnection sections 7A and 7B, each of which includes a pair of contact pieces 12, a compression coil spring, and two screw bolts. It is installed. At the rear end of the penetrating conductor 16, the lower end of the connecting conductor 15 is fastened with a bolt. On the other hand, a handle (not shown) is attached to the front surface of the unit frame 8.

In the power conversion unit configured as described above, the connection on the load side is achieved by pushing the unit frame 8 to the rear of the box in which the unit frame 8 is housed. The contact pieces 12 of the female disconnecting portions 7A and 7B are fitted to short male U-shaped terminals (not shown) projecting from the front of a bus bar (not shown) arranged at the rear of the housed box. On the contrary, when disconnecting the connection on the load side, the unit frame 8 is pulled out forward, and the female disconnection portions 7A and 7B fitted to the male terminals are pulled out.

When connecting a flexible conductor or a cable or bus to the positive electrode side input terminal 5A and the negative electrode side input terminal 5B, the conventional cable connecting the AC side output terminal 6 and the load side is eliminated. The work is easy and the replacement of the IGBTs 1A and 1B and the withdrawal of the unit frame 8 at the time of maintenance / inspection become easy.

On the other hand, as shown in FIGS. 2 and 3, the electric path from the positive electrode side input terminal 5 A to the female disconnecting section 7 via the positive electrode side conductor 3 A, the AC side conductor 4 and the connecting conductor 15 is at the front end, the middle and The paths passing through any of the rear end IGBTs 1A have the same length, and the resistance values including the inductance of the electric paths are also the same, so that the currents flowing through the respective IGBTs 1A can be made equal. This also applies to the lower IGBT 1B, and the temperature rise of each IGBT 1A, 1B can be made uniform.

In the above embodiment, the IGBTs 1A and 1B attached to both side surfaces of the heat sink 2 are described with the collector electrode C on the upper side. The conductor may be the negative electrode side conductor and the lower conductor may be the positive electrode side conductor.

[0020]

[Effect of the device]

 As described above, according to the present invention, a plurality of switching elements are attached to the upper and lower stages of both sides of the heat sink housed in the unit with the polarities of the upper and lower terminals in the same direction. The lower terminals of the switching element are connected to each other by a DC side conductor having an input terminal at the front of the unit, and the lower terminal of the upper switching element and the upper terminal of the lower switching element are connected to the common side conductor. In the power conversion unit connected with, the disconnection part connected to the rear end of the AC side conductor is provided at the rear part of the unit so that the DC side conductor and each switching element are connected to the rear side of the AC side conductor from the input terminal. The length of the electric path to the end is the same for the electric paths that pass through each switching element, and the external connection work is done only with the input terminals. Inspection is easy, it is possible to obtain a power conversion unit which can prevent low under the lifetime due to current imbalance in the switching element.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a power conversion unit of the present invention.

FIG. 2 is a view on arrow A in FIG.

FIG. 3 is a connection diagram showing the operation of the power conversion unit of the present invention.

FIG. 4 is a perspective view showing an example of a conventional power conversion unit.

5 is a view on arrow B of FIG.

[Explanation of symbols]

1A, 1B ... IGBT, 2 ... Heat sink, 3A ... Positive conductor, 3B ... Negative conductor, 4 ... AC conductor, 5A ... Positive input terminal, 5B ... Negative input terminal, 6 ... AC output terminal, 7A , 7B ... Female disconnector, 8 ... Unit frame.

Claims (1)

[Scope of utility model registration request] 1. A plurality of switching elements are attached to the upper and lower tiers of both sides of a heat sink housed in a unit, with the polarities of the upper and lower terminals in the same direction, and the upper terminals of the switching ele- ments of the upper tier and the lower tier. The lower terminals of the switching element are connected to each other by a direct current side conductor having an input terminal at the front of the unit, and the lower terminal of the upper switching element and the upper terminal of the lower switching element have a common AC A power conversion unit connected by a side conductor, wherein a disconnecting part connected to a rear end of the AC side conductor is provided at a rear part of the unit.