JP6330642B2 - Power converter - Google Patents

Description

  The present invention relates to a power conversion device suitable for use at a high voltage formed by connecting a plurality of unit power conversion cells in series.

  Directly driving an AC motor driven by a high voltage, for example, a voltage of 3 kV or higher, with a power conversion device constituted by a high voltage inverter has already been performed. As such a high-voltage power conversion device, as shown in Patent Document 1, it is configured to connect the outputs of a plurality of unit power conversion cells in series.

  As shown in FIG. 8A, such a conventional power converter includes a power converter (converter) 54 that converts AC power into DC power, and a power converter (inverter) that converts DC power into AC power. ) 55 and a plurality of unit power conversion cells 57 (57a to 57c) each including a capacitor 56. The input terminals R, S, and T of the unit power conversion cell 57 are connected to the AC power source 51 through the isolation transformer 52, respectively. The output terminals AC1 and AC2 are connected in series, and a load 59 is connected between the series connection terminals. Further, a bypass circuit 58 (ac) constituted by a switch that is normally open is provided between the AC power output terminals AC1 and AC2 of each unit power conversion cell.

  Each unit power conversion cell 57 includes a rectifier circuit 54, an inverter circuit 55, and a smoothing capacitor 56, as shown in FIG. The rectifier circuit 54 is a circuit configured by connecting semiconductor rectifier elements in a bridge connection. The inverter circuit 55 is a circuit configured by bridge-connecting semiconductor switch elements. The smoothing capacitor 56 is connected between the rectifier circuit 54 and the inverter circuit 55.

  In the power conversion device configured as described above, when any unit power conversion cell fails, the output terminals of the failed unit power conversion cell 57 are short-circuited by closing the switch of the bypass circuit 58. Bypassing the failed unit power conversion cell 57 reduces the capacity, but the power conversion device can continue operation.

  The bypass circuit can be accommodated in each unit power conversion cell. Alternatively, as shown in FIG. 9, a bypass circuit board 63 is provided separately from the transformer board 61 that houses the transformer 52 and the power conversion board 62 that houses the plurality of unit power conversion cells 57a to 57c, and the bypass circuit is provided here. 58a-58b may be stored.

Japanese Patent Laid-Open No. 02-202324

  Provision for a device failure is determined by the application of the load connected to the device. Generally, it is determined in consideration of the balance between the loss while the apparatus is stopped and the spare part cost. Moreover, since many electric components, such as a converter circuit, an inverter circuit, and a smoothing capacitor, are mounted in the unit power conversion cell, spare parts are also expensive. For this reason, except for the case where the operation is hardly allowed to be interrupted, the downtime is short and the spare parts cost is required to be low. However, the conventional apparatus has the following problems.

  First, when a bypass circuit is accommodated in each unit power conversion cell, the price of the unit power conversion cell increases.

  Further, when the bypass circuit is housed in an independent board, not only the price of the apparatus increases, but also the entire apparatus becomes large.

  Therefore, in order to solve the above problems, an object of the present invention is to provide a power conversion device suitable for high voltage use that can reduce the price of the device and can be configured in a small size as a whole.

  In order to solve such a problem, the present invention provides a unit power conversion cell that is configured by housing component devices constituting a power conversion circuit in one box and can be used in series with each other. In addition, a required space where the components are not housed is provided on the back side of the box, and an openable / closable opening communicating with the space is provided on the back plate of the box. Furthermore, a bypass circuit unit that is integrally formed with a switch that opens and closes an electric circuit and its control circuit is provided in a unit frame that can be inserted into and removed from the opening of the box. And the bypass circuit unit is inserted from the opening of the back plate of the box body of the unit power conversion cell that requires a bypass circuit, and the switch is connected in parallel with the output terminal of the unit power conversion cell in the space. In addition to being connected, the frame unit is attached and fixed to the back plate of the box, and the opening is closed.

  In this invention, the flange part used as the guide body at the time of insertion can be provided in the unit frame of the said bypass circuit unit at the outer periphery that contacts a part of the box of the said unit power conversion cell.

  In addition, the unit power conversion cell has a box in which a cooling air can flow and a box in which the cooling air cannot flow, and a space in which the component device is not stored is provided in the box where the cooling air cannot flow. Good.

  Furthermore, the connection part between the output terminal of the unit power conversion cell and the switch of the bypass circuit unit can be an insertion contact structure in which the other terminal is inserted into the receiving part of one terminal for connection.

  According to the present invention, the unit power conversion cell can be manufactured at a low cost by providing the empty space in which nothing is accommodated inside and not including the bypass circuit unit. In addition, since the unit power conversion cell that requires a bypass circuit can be built in by storing the bypass circuit unit in the above-described space, a separate bypass circuit board is not required, so the entire apparatus can be Can be configured small.

It is a perspective view which shows the external appearance seen from the back side of the unit power conversion cell which is not provided with the bypass circuit unit by the Example of this invention, (a) shows the state which obstruct | occluded the opening of the backplate, (b) The state which opened this opening is shown. It is a side view which removes the side plate and some support frame of the unit power conversion cell which is not provided with the bypass circuit unit by the Example of this invention. It is a disassembled perspective view of the unit power conversion cell provided with the bypass circuit unit by the Example of this invention. It is a side view which removes and shows a side plate and some support frames of a unit power conversion cell provided with a bypass circuit unit by an example of this invention. It is a figure which shows the assembly work process of the bypass circuit unit to the unit power conversion cell in this invention. It is a partial side view which expands and shows the principal part for demonstrating the assembly | attachment work to the unit power conversion cell of the bypass circuit unit in this invention. It is a top view which shows the insertion contact used for this invention. It is the block circuit diagram (a) which shows the structure of the power converter device using the conventional unit power conversion cell, and the circuit block diagram (b) of a unit power conversion cell. It is a typical block diagram of the power converter device using the conventional unit power conversion cell.

  Embodiments of the present invention will be described with reference to the embodiments shown in the drawings.

  1 to 4 show an embodiment of a unit power conversion cell according to the present invention. 1 and 2 show a standard unit power conversion cell without a bypass circuit. 3 and 4 show a unit power conversion cell including a bypass circuit.

  The standard unit power conversion cell 1 includes a box 10 constituting the main body. The back plate 11 of the box is provided with an opening 11b that can be opened and closed by a lid plate 11a (FIG. 1A). By removing the fixing screw and removing the cover plate 11a, the opening 11b can be opened as shown in FIG.

  In this embodiment, as shown in FIG. 2, the box 10 is partitioned into three stages by partitioning the inside with partition walls 12 and 13. The upper compartment 14 and the lower compartment 15 are provided with exhaust ports 14a and 15a (the front-side intake ports are not shown) for intake and exhaust of cooling air on the front and rear surfaces, respectively. Therefore, the cooling air in the compartment 14 and the lower compartment 15 flows through so as to be sucked from the front intake port and discharged from the rear exhaust port.

  The middle compartment 16 communicates with the opening 11b provided in the back plate 11, but is closed by the lid plate 11a. Therefore, the cooling air from the outside cannot flow through the inside of the compartment 16. A space 16s having a required size is formed on the back side of the middle compartment 16 where the cooling air cannot flow.

  In the standard unit power conversion cell 1, the empty space 16s is empty without any space.

  A cooling body 22 with cooling fins is housed in the upper compartment 14. The cooling body 22 is coupled to a semiconductor module element 21 configured by modularizing a semiconductor rectifier element and a semiconductor switch element housed in the middle compartment 16. The lower compartment 15 houses a capacitor 23 that smoothes the DC voltage of the DC intermediate circuit of the power converter. The capacitor connection terminal 23 a penetrates the partition wall 13 made of an insulating material and protrudes into the adjacent compartment 16. The connection terminals of the semiconductor module element 21, the connection terminal 23 a of the capacitor 23, and the input terminal 25 and the output terminal 26 provided on the front surface of the box 10 are all connected to each other by the bar-shaped connection conductor 27. It is performed in the compartment 16 where the flow-through is impossible.

  A conductor branched from the conductor connected to the output terminal 26 on the front surface is extended into the space 16s of the compartment 16 to form a branched output terminal 28.

  The standard unit power conversion cells configured as described above constitute a power conversion device by placing the required number in a common panel. When operating such a power converter, each unit power conversion cell is cooled by forcibly flowing cooling air into the panel by a cooling fan provided outside. In the unit power conversion cell, this cooling air flows through the upper compartment 14 and the lower compartment 15 configured to allow the cooling air to flow therethrough, and cools the components housed in each of the compartments. However, since the middle compartment 16 in which the connection conductor is accommodated is configured such that the cooling air cannot flow therethrough, the cooling air does not flow therethrough. Thus, since cooling air does not flow through the compartment 16, the adhesion and accumulation of fine dust in the outside air contained in the cooling air hardly occur. Therefore, even if the connection conductor is a bare conductor, the occurrence of an insulation failure is suppressed.

  Next, in order to improve the operation reliability of the power conversion device, an embodiment of the power conversion device in which a bypass circuit is provided in a standard unit power conversion cell is shown in FIGS.

  In this embodiment, as the unit power conversion cell 1, the standard unit power conversion cell 1 shown in FIGS. 1 and 2 is used, and in addition, a bypass circuit unit 30 is prepared.

  The bypass circuit unit 30 includes a switch 32 constituted by an electromagnetic switch or the like that opens and closes an electric circuit on a unit frame 31, a transformer 34 that constitutes a control circuit that controls the opening and closing of the switch 32, and a switch The lead terminal 33 drawn out from 32 is integrated into a unit.

  In order to attach this bypass circuit unit 30, the cover plate 11a of the back plate 11 is removed from the unit power conversion cell 1, and the opening 11b of the back plate 11 is opened. The bypass circuit unit 30 is inserted into the box 10 from the opened opening 11b, and is stored in a space 16s provided in advance in the box 10 of the unit power conversion cell. Then, the unit frame 31 of the bypass circuit unit is screwed and fixed to the back plate 11 of the box 11, thereby closing the opening 11 b of the back plate 11.

  Thereby, as shown in FIG. 4, the back side of the middle compartment 16 in the box 10 of the unit power conversion cell 1 is closed. Since the cooling air supplied from the outside cannot flow through the compartment 16, a configuration in which the cooling air cannot flow through the compartment 16 is maintained.

  The lead-out terminal 33 of the switch 32 of the bypass circuit unit 30 housed in the space 16s is branched from the output terminal 26 of the unit power conversion cell to the branch output terminal 28 provided in the space 16s in the compartment 16. Connecting. If the switch 32 of the bypass circuit unit 30 is closed, the output terminals 26 of the unit power conversion cell 1 can be short-circuited, and the cell 1 can be bypassed.

  The process of assembling the bypass circuit unit 30 into the unit power conversion cell 1 is shown in FIGS. 5A to 5D, and the work process will be described in more detail with reference to FIG.

  FIG. 5 (a) shows that the opening 11 b of the back plate 11 is opened to remove the cover plate 11 a of the back plate 11 of the box 10 of the unit power conversion cell 1 and incorporate the bypass circuit unit 30 into the unit power conversion cell 1. It is in the state.

  Here, as shown in FIG. 5 (b), the prepared bypass circuit unit 30 is moved in the direction of the arrow, and the opening 11 b of the back plate 11 of the opened box 10 is moved to the space 16 s of the box 10. insert. Then, the lead-out terminal 33 of the bypass circuit unit 30 is brought into contact with the branch output terminal 28 drawn into the space 16s.

  In order to make this insertion work smooth, as shown in FIG. 6, the upper end of the unit frame 31 of the bypass circuit unit 30 has a U-shaped cross section and is provided with a fixing flange 31a. At the time of insertion, a finger is put on the fixing flange 31 a, and the upper surface thereof is applied to the lower surface of the partition plate 12 that forms the upper compartment 14 of the box 10, and is pushed in until the fixing flange 31 a hits the back plate 11. If it does in this way, since the position of the upper end of bypass circuit unit 30 is fixed, insertion work will be stabilized and performed smoothly.

  After that, as shown in FIG. 5C, the side plates 29, 29 on both sides of the box 10 of the unit power conversion cell 1 are removed, and the lead-out terminal 33 of the bypass circuit unit 30 and the branch output terminal in the space 16s. The contact state with 28 can be seen. In the child state, both terminals of the bypass circuit unit 30 are fastened and coupled with screws 33a. In addition, the unit frame 31 of the bypass circuit unit 30 is fixed to the back plate 11 of the box 1 by screwing.

  Thereby, as shown in FIG.5 (d), the assembly of the bypass circuit unit 30 to the unit power conversion cell 1 is completed. Thereafter, the unit power conversion cell 1 incorporating the bypass circuit is completed by closing the side surface of the box 10 with the side plate 29.

  In the above, the branch output terminal 28 branched from the output terminal 26 of the unit power conversion cell and the lead-out terminal 33 of the bypass circuit unit 30 are connected by screw coupling. In order to simplify this connection work, as shown in FIG. 7, an insertion-type terminal 28a is formed at the branch output terminal 28, and a lead-out terminal 33 of the flat plate-type bypass circuit unit 30 is inserted into this. An insertion type terminal structure can be adopted.

1: Unit power conversion cell 10: Box 11: Back plate 11a: Cover plate 11b: Opening 16s: Empty space 21: Semiconductor module element 23: Capacitor 25: Input terminal 26: Output terminal 28: Branch output terminal 30: Bypass circuit Unit 31: Unit frame 32: Switch 33: Lead-out terminal 34: Transformer

Claims (4)

In a plurality of unit power conversion cells that are configured by housing component devices constituting a power conversion circuit in a single box and can be used by connecting output terminals in series, the back side of the box includes the unit A configuration in which a required space that does not contain the component equipment is provided, an openable / closable opening that communicates with the void is provided in the back plate of the box, and a structure that can be taken in and out of the box from the opening of the box in the unit frame, the switch and bypass circuit units unitized integrally attached to the control circuit for opening and closing the electric path is provided, wherein the back plate of the box body of the respective unit power conversion cells requiring a bypass circuit inserting said bypass circuit unit from the opening in said cavity, thereby connecting the switch in parallel to the output terminal of each of the unit power conversion cells, the unit frame And mounted and fixed to the back plate of the serial box body, a power conversion apparatus characterized by closing the opening. 2. The unit frame of the bypass circuit unit is provided with a flange portion on the outer peripheral edge thereof, which is in contact with a part of the box of each unit power conversion cell and serves as a guide body at the time of insertion. The power converter described. A section in which cooling air can flow and a section incapable of flowing cooling air are provided inside the box of each unit power conversion cell, and a space in which the components are not stored is provided in a section where the cooling air cannot flow. The power conversion device according to claim 1, wherein the power conversion device is a power conversion device. The connection portion between the output terminal of each unit power conversion cell and the switch of the bypass circuit unit has an insertion contact structure in which the other terminal is inserted into the receiving portion of one terminal and connected. The power converter device of any one of Claim 1 thru | or 3.

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