JP2007129838A - Power converter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wiring structure that can easily perform the connection and disconnection of units accommodated in a board by access from the outside of the board. <P>SOLUTION: This power converter is configured such that a switching element and a smoothing capacitor of a power conversion circuit are constituted of individual units, and terminals of connecting conductors drawn out of the units are screw-fastened and wired after each unit is accommodated in a single board. As for an inverter as an example, an inverter unit 1 and a smoothing capacitor unit 2 are accommodated separately on upper and lower stages on the board 5, seating faces of a terminal 6a drawn out of a connecting conductor 6 of the capacitor unit and a terminal 12a of a connecting conductor 12 drawn out upward from the inverter unit 1 are disposed so that they are aligned at the right and left toward front and rear faces of the board, the units 1, 2 are accessed from the backside of the board 5 in a state that the units are accommodated and set in the board, and the terminals 6a, 12a that are overlapped with each other in the fore-and-aft direction are fastened and connected with screws 7. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a power converter for a medium- and large-capacity inverter applied to motor control, and more particularly to a wiring structure between a switching element unit and a smoothing capacitor unit housed in a panel.

First, as an implementation target example of the present invention, FIG. 5 shows a circuit diagram of a three-level inverter, and FIGS. 6A and 6B show an example of a specific assembly structure in the prior art. In FIG. 5, 1 is an inverter unit comprising an inverter circuit composed of a plurality of IGBTs (switching elements) 11 and diodes 11b, 2 is a smoothing capacitor unit comprising a plurality of capacitors 21, 3 is a load (motor), and 4 is an input. (DC) side main circuit bus (P is positive electrode, N is negative electrode, O is neutral point). Inverter unit 1 and smoothing capacitor unit 2 are housed in a panel (inverter panel) 5 as shown in FIG. ing.
Here, the inverter board 5 is a metal closing board provided with an opening / closing door 5a on the front side and a panel 5b on the back side, and the smoothing capacitor unit 2 is arranged on the upper side of the board and the inverter unit 1 is arranged on the lower side. Yes.

  In addition, the inverter unit 1 has a plurality of IGBTs 11 arranged in its assembly frame (housing), and is wired with a connection conductor 12 (for example, a low-inductance laminated bus bar is adopted so as to reduce the snubber). Above, an input side terminal 12a is drawn upward from the frame of the unit, and an output side terminal (AC) 12b is drawn behind. Reference numeral 13 denotes a heat sink (cooling plate) on which the IGBT 11 is mounted, and reference numeral 14 denotes an IGBT gate control circuit. On the other hand, the smoothing capacitor unit 2 is connected to the main circuit bus 4 via the connection conductor 6 laid on the lower surface side of the assembly frame after a plurality of capacitors 21 are assembled in the assembly frame. A terminal 6a is drawn downward from the conductor 6, this terminal 6a and the terminal 12a drawn from the inverter unit 1 are overlapped, and a screw 7 is fastened from the side so that the inverter unit / smoothing capacitor unit are connected by wiring. I have to.

An inverter device having a configuration in which an inverter unit and a smoothing capacitor unit are housed in the panel as independent units as described above and wired between them with a connecting conductor is known, for example, in Patent Document 1.
JP 2001-268912 A

When considering the maintainability of the inverter device in which the inverter unit and the smoothing capacitor unit are accommodated in a single panel as described above, the conventional assembly structure shown in FIG. 6 has the following problems.
That is, in the case of a small-to-medium capacity inverter, the smoothing capacitor unit 2 is mounted on the inverter unit 1 in FIG. 6 and the two units are assembled together and stored in the panel. The unit 2 can be pulled out of the panel and inspected and repaired. However, in the case of a large-capacity inverter, the number of IGBTs 11 and smoothing capacitors 21 is increased so that the inverter unit 1 and the smoothing capacitor unit 2 are large and heavy. Therefore, each unit is individually housed in the panel, and each unit is separately pulled out of the panel for maintenance and maintenance.

By the way, in order to individually pull out the units stored in the panel during maintenance, it is necessary to disconnect the wiring connecting the units. In this regard, in the conventional assembly structure shown in FIG. 6, both the terminal 12a of the connecting conductor 12 drawn upward from the inverter unit 1 and the seating surface of the terminal 6a drawn downward from the connecting conductor 6 of the smoothing capacitor unit 2 are both. The terminals of P, N, and O are lined up in the front-rear direction and overlapped with the terminals on the connection partner side. For this reason, it is very difficult to access the inside of the narrow board from outside the board and loosen or tighten the screw 7 with a tool.
The present invention has been made in view of the above points. The object of the present invention is to solve the above-mentioned problems and improve the wiring structure so that connection and disconnection between units can be easily performed by accessing from outside the panel. An object of the present invention is to provide an improved power conversion device.

In order to achieve the above object, according to the present invention, the switching element and the smoothing capacitor of the power conversion circuit are constructed by individual units, and each unit is housed in a single panel and then pulled out from the unit. In the power conversion device wired between the terminals of the connecting conductors with screws,
The seating surface of each terminal pulled out from the connecting conductor of the unit to the connecting counterpart unit side is arranged on the left and right toward the front and back surfaces of the panel, and the units overlap in the front and back in a state of being set in the upper and lower stages and housed in the panel The terminals are connected by screw fastening (Claim 1).
Moreover, in the said structure, the connection conductor of each unit is a laminated bus bar, and it is made to pull out a terminal to the right-and-left one line in alignment with the direction of a seat surface from each conductor sheet (Claim 2).

  According to the above configuration, in a state where the switching element and smoothing capacitor units are housed in the panel, the terminal seat surfaces of the connecting conductors drawn from the unit face in the front-rear direction of the panel and overlap in a line in the left and right direction. . Therefore, by accessing the inside of the board from the back (or front) of the board in this state, it is possible to easily tighten and detach the screws that fasten the terminals of the connecting conductors, which greatly improves the maintenance workability. Improvements can be made.

Embodiments of the present invention will be described below based on the examples shown in FIGS. In addition, in the figure of an Example, the same code | symbol is attached | subjected to the member corresponding to FIG. 6, and the description is abbreviate | omitted.
That is, in the illustrated embodiment, first, the inverter unit 1 housed on the lower side of the panel 5 and the smoothing capacitor unit 2 housed on the upper side have an independent drawer-type unit structure, and guide rails laid on the panel side. It is mounted (not shown) and stored so that it can be pulled forward. Further, in the conventional wiring structure shown in FIG. 6, the input side terminal 12a of the connecting conductor 12 drawn upward from the inverter unit 1 and the seating surface of the terminal 6a drawn downward from the connecting conductor 6 of the smoothing capacitor unit 2 are provided. In the wiring structure of the embodiment shown in FIGS. 1A and 1B, the P, N, and O terminals are both arranged left and right and the positions of the P, N, and O terminals are shifted in the front-rear direction. The bearing surfaces of the terminals 6a and 12a are both front and rear, and the P, N, and O terminals are arranged in a horizontal row.

When the inverter unit 1 and the smoothing capacitor unit 2 are stored in the panel 5, the smoothing capacitor unit 2 stored on the upper side of the panel 5 is set first as shown in FIG. The lower inverter unit 1 that is frequently used is accommodated and set later. As a result, as shown in FIG. 1A, the terminal 12a on the inverter unit 1 side overlaps the front surface of the terminal 6a drawn from the connection conductor 6 of the smoothing capacitor unit 2 in the housed and set state.
Therefore, in this state, by opening the back panel 5b of the panel 5 and accessing it from outside the panel, the fastening screws 7 can be easily loosened or tightened using a tool (driver) to each terminal of P, N, O. Can be. Even when only the inverter unit 1 is pulled out from the panel 5 at the time of maintenance, after the connection conductor terminals are disconnected by the screw operation, the upper smoothing capacitor unit 2 remains in the panel 5 The front door 5a can be opened and the inverter unit 1 can be pulled out without interference with the smoothing capacitor unit 2 for inspection and repair.

  Next, the detailed structure of the connection conductor 6 laid on the lower surface side of the smoothing capacitor unit 2 in FIG. 1 will be described with reference to FIGS. 3 is a cross-sectional view schematically showing the connection between the capacitor 21 and a laminated bus bar (connection conductor) to be described later, FIG. 4A is a perspective view of a terminal lead-out portion of the laminated bus bar, and FIG. (A) It is an exploded view of a figure. That is, in the embodiment of FIG. 1, a laminated bus bar is employed as the connecting conductor 6 of the smoothing capacitor unit 2, and the laminated bus bar is composed of three conductor sheets (copper having a thickness of about several millimeters) corresponding to P, N, and O. Material sheet) 6b is sandwiched between four insulating sheets 6c and is integrally molded, and the stud terminal 21a of the capacitor 21 is coupled and electrically connected to the designated connection portion of the conductor sheet 6b. ing. In addition, plate-like terminals 6a are individually drawn out from the conductor sheet 6b corresponding to the P, N, and O poles at the rear end of the laminated bus bar. The terminal 6a is bent at the tip downward and has a threaded hole formed in the seating surface, and the seating surface is aligned in the front-rear direction as described above, and each of the P, N, and O terminals Are arranged in a line on the left and right. In the storage state of each unit shown in FIG. 1, the seating surface of the terminal 12a drawn from the inverter unit 1 is overlapped with the seating surface of the terminal 6a, and the screw 7 passed therethrough is fastened to connect and wire. In addition, wiring between the laminated bus bar 6 and the input-side bus 4 can be performed using the terminal 6a.

  In the illustrated embodiment, the wiring structure in the panel is described by taking the inverter as an example, but the maintenance workability can be improved by adopting the same wiring structure in the converter.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an assembly structure diagram of a power converter according to an embodiment of the present invention, where (a) is a side view of an inverter unit and a smoothing capacitor unit housed in a panel, and (b) is a rear view of (a). 1 is a schematic perspective view showing the procedure for storing the inverter unit in the panel with the configuration of FIG. Schematic diagram showing the connection structure between the capacitor in Fig. 1 and the laminated bus bar adopted as its connection conductor FIG. 4 is a structural diagram of a terminal lead-out portion of the laminated bus bar shown in FIG. 3, where (a) is a perspective view and (b) is an exploded view of (a). Circuit diagram of a three-level inverter as an application example of the present invention FIG. 6 is an assembly structure diagram of a conventional example corresponding to the inverter of FIG. 5, (a) is a side view of the inverter unit and smoothing capacitor unit housed in the panel, and (b) is a rear view of (a).

Explanation of symbols

1 Inverter unit 11 IGBT (switching element)
12 Connection conductor 12a Terminal 2 Smoothing capacitor unit 21 Capacitor 4 Input side main circuit bus 5 Panel 5a Front door 5b Rear panel 6 Connection conductor of capacitor unit (laminate bus bar)
6a Terminal 6b Conductor sheet 6c Insulation sheet 7 Screw

Claims (2)

Power that is constructed by switching elements and smoothing capacitors of the power conversion circuit as individual units, and each unit is housed in a single panel, and the connection conductor terminals drawn from that unit are screwed between the terminals. In the conversion device,
The seating surface of each terminal pulled out from the connecting conductor of the unit to the connecting counterpart unit side is arranged on the left and right toward the front and back surfaces of the panel, and the units overlap in the front and back in a state of being set in the upper and lower stages and stored in the panel A power conversion device, wherein the terminals are screwed and wired. 2. The power conversion device according to claim 1, wherein the connection conductor of each unit is a laminated bus bar, and terminals are drawn out from each conductor sheet in a line on the left and right sides in alignment with the direction of the seating surface.

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