JP5326655B2 - Power converter - Google Patents

Description

  The present invention relates to a power conversion device used as a power source for driving control of an electric motor or the like.

  As a general structure of a power conversion device for driving and controlling an electric motor, etc., in order to facilitate inspection and replacement of parts, etc., a plurality of power conversion units that are divided into a plurality of conversion circuits and combined into a unit are combined. A so-called unit structure that is housed in a stack has been conventionally employed (see Patent Document 1 and Patent Document 2).

  A conventional example of a power conversion device employing such a unit structure is shown in FIGS.

  In the conventional circuit of FIG. 7, AC power from the commercial power source 1 is converted into DC power by the converter circuit 2. The smoothing capacitor 3 connected to the DC intermediate circuit absorbs and removes the pulsation contained in the DC power and smoothes it. The smoothed DC power is input to the respective inverter circuits 4R, 4S, and 4T through the three protective fuses 10R, 10S, and 10T. The inverter circuit 4R includes a transistor bridge circuit 6R having a structure in which transistors as semiconductor switching elements are bridge-connected, and a base drive circuit 5R for turning on / off the transistor bridge circuit 6R. The inverter circuit 4S The inverter circuit 4T has the same configuration. Three-phase AC power is obtained from these three inverter circuits 4R, 4S, 4T, and the induction motor 9 is operated at a desired rotational speed.

  A power supply circuit 13 that receives power supply from the DC intermediate circuit supplies power to the base drive power supply circuit 14 and the control circuit 8, and the base drive power supply circuit 14 supplies power to the phase base drive circuits 5R, 5S, and 5T. Supply. Here, for example, if an arm short circuit accident occurs in the transistor bridge circuit 6R, an excessive current flows through the transistor bridge circuit 6R due to the arm short circuit accident, so that the protective fuse 10R is blown and the transistor bridge circuit 6R is overcurrent destroyed. In recent years, it has become increasingly difficult to protect a transistor from overcurrent breakdown with a protective fuse. However, even when the overcurrent breakdown of the transistor bridge circuit 6R cannot be prevented, the protective fuse 10R can be blown to prevent an accident from spreading to the remaining transistor bridge circuits 6S and 6T (not shown). Each of the protection fuses 10R, 10S, and 10T is provided with a disconnection detection circuit 11R, 11S, and 11T, respectively, and if the protection fuse is blown, the information is given to the control circuit 8, and the failure display circuit 12 has which protection. Displays whether the fuse has blown.

  The inverter device shown in FIG. 7 is housed in the stack 15 as shown in FIG. The converter circuit 2 shown in FIG. 7 is mounted as a unit on the converter circuit tray 16 in FIG. 8 is unitized and mounted on the inverter tray 17R of FIG. 8. Similarly, the inverter circuit 4S and inverter circuit 4T of FIG. 7 are unitized on the inverter tray 17S and inverter tray 17T of FIG. 8, respectively. It is installed. Since each of these trays is stored in the stack 15 and can be easily pulled out, for example, if it is known that the transistor bridge circuit 6R is broken as described above, the inverter tray 17R is pulled out according to the instruction of the failure display circuit 12. Check and replace damaged parts. Although shown in FIG. 7, the components that are not mounted on these trays are stored in the space 18 below the stack 15.

  When a failure occurs in a unit-structure power conversion device in this way, only the failed power conversion unit is removed from the stack and repaired or replaced with a spare power conversion unit. can do.

  In this case, the power conversion unit to be repaired or exchanged is small because it is unitized, so it is easy to handle when removed and transported, but repair and replacement with spare parts During the operation, it is necessary to stop the operation of the power conversion device, and thus there is a problem that it takes a long time to recover.

  In addition, for example, in the case of a power conversion device installed in a narrow space such as a power conversion device used to drive a propulsion device such as an electric vehicle or an electric propulsion ship, not only is the recovery work itself associated with a failure difficult to perform. There is also a problem that it is not easy to secure a storage space for spare parts and a storage space for defective parts.

  In conventional power converters, these problems are not adequately addressed, so even if a part of the power converter fails, it must continue operation, or it can fail in a short time. It was not possible to use it for the device that needs to be restored.

Japanese Patent Laid-Open No. 08-126329 Japanese Patent Laid-Open No. 11-069841

  In order to eliminate the inconvenience of the conventional device described above, when a failure occurs in some power conversion units of the power conversion device, the operation is continued without completely separating the failed power conversion unit from the stack. It is an object of the present invention to provide a power conversion device that can shorten the recovery time and does not need to separate the failed power conversion unit from the main body and move it to a special storage space. is there.

In order to solve the above-described problems, the present invention divides a power conversion circuit into a plurality of units, and each of the divided units is incorporated in a drawer-type tray to form a plurality of power conversion units. A power conversion device that is housed in a stack so as to be able to be inserted and removed, and is provided with a disconnection portion that connects and disconnects an internal circuit and an external circuit of each unit according to the insertion and removal of the power conversion unit between each power conversion unit and the stack In
At the connection position where each power conversion unit is inserted into the stack and the disconnection portion is in a connected state, the stack is obtained by maintaining the connection state of the disconnection portion with the normal fixing bolt having a short length. At the disconnection position where each power conversion unit is pulled out of the stack and the disconnection part is disconnected, the long disconnector fixing bolts each having a spacer for maintaining the disconnection interval of the disconnection part are used. The power conversion unit is fixed to the stack while maintaining a disconnection state of the disconnection portion.

  Moreover, the power converter device of this invention is good to provide the disconnection confirmation means which confirms a connection state in the said disconnection part.

  This invention divides the power conversion circuit into a plurality of units, each of the divided units is assembled in a drawer-type tray to form a plurality of power conversion units, and each power conversion unit is stored in a stackable manner, In addition, in each power conversion device, the power conversion unit is provided with a disconnection unit that connects and disconnects the internal circuit and the external circuit of the unit according to the insertion and removal of the power conversion unit between each power conversion unit and the stack. Each power conversion unit is connected to the stack at each of a connection position where the disconnection part is inserted into the stack and the disconnection part is pulled out and the disconnection part is pulled out of the stack and the disconnection part is disconnected. Since a fixing means for fixing is provided, when a failure occurs in any of the power conversion units, This unit is temporarily held by the stack by stopping the operation of the failed power conversion unit and fixing the unit to the stack in a state where the unit is pulled out of the stack to the disconnection position where the disconnection part is disconnected. can do.

As a result, the operation of the power conversion device can be continued with the remaining normal power conversion units in a state where the failed power conversion unit is disconnected from the device and held in the stack. The time to recover to a possible state can be remarkably shortened, and the failed power conversion unit can be fixed and held on the stack in a disconnected state, so that no special storage space for the failed unit is required. An effect is obtained.

It is a circuit block diagram of the power converter device by the Example of this invention. It is a circuit block diagram of the power conversion unit used for the power converter device of this invention. It is a block diagram of the stack | stuck which attached the power conversion unit in the power converter device of this invention, (a) is a front view, (b) is side sectional drawing. It is a partial plane sectional view which shows the attachment state in the connection position of the power conversion unit in the power converter device of this invention. It is a partial plane sectional view which shows the attachment state in the disconnecting position of the power conversion unit in the power converter device of this invention. It is a top view which shows the fixing bolt used for this invention. It is a circuit block diagram of the conventional power converter device. It is a perspective view which shows the structure of the conventional power converter device.

  Embodiments of the present invention will be described with reference to the examples shown in FIGS.

  FIG. 1 shows an embodiment of a power conversion device of the present invention constituted by an inverter for driving an AC motor M at a variable speed. The power conversion device constitutes two sets of three-phase inverters by single-phase inverter units U1, U2, V1, V2, W1, and W2 that convert DC power supplied from DC power buses P and N into AC power. A single-phase inverter unit for each phase is connected to each phase winding U, V, W of the three-phase AC motor M, and supplies three-phase AC power to the AC motor M. The electric power supplied to the AC motor M is controlled by the three-phase inverter to control the speed of the AC motor M.

  Each single-phase inverter unit includes a single-phase inverter circuit INV constituted by semiconductor elements Q1 to Q4 and its control circuit CTR as shown in FIG. 2, and is integrated into one unit tray UT to be unitized. The unit also includes a smoothing capacitor C, an input current detector CTD for detecting DC input current, an output current detector CTA for detecting AC output current, and a fuse for protecting the inverter circuit INV from overcurrent of the DC input current. A fuse FU is provided to protect against FP and AC overcurrent. The fuses FP and FU are respectively provided with blown alarm contacts FPA and FUA that turn on the contact and generate an alarm output when the fuse is blown.

  As shown in FIG. 3, each unit tray UT comprises a drawer-type tray that can be inserted into and pulled out from the stack ST, and the tray is inserted into the back of the tray to connect the circuit inside the tray and the outside circuit. The main circuit disconnecting part MDS and the auxiliary circuit disconnecting part SDS which are interrupted by the pull-out operation are provided. The main circuit disconnection unit MDS is for disconnecting the main circuit that connects the inverter circuit INV, the DC input buses P and N, and the AC output buses U and V. The auxiliary circuit disconnecting part SDS connects and disconnects auxiliary circuits such as a disconnection confirmation circuit DSC for confirming the disconnection state of the ground circuit and the disconnecting part. The disconnection confirmation circuit DSC connects the two disconnection terminals with a conductor, and confirms the conduction state between the two disconnection terminals with the control circuit CTR on the unit side. Further, on the front surface of the unit tray UT, there is a control circuit connector CNT for connecting a control cable for connecting the control circuit CTR and an external monitoring control device, and a handle HD for gripping the tray when inserting and pulling out. Is provided.

  Such an inverter unit circuit is incorporated in a drawer-type unit tray UT to constitute inverter units U1, U2 to W1, W2, and is inserted into the stack ST so as to be drawable as shown in FIG. Is fixed by a normal fixing bolt A (see FIG. 6) having a short length at the connection position where the is connected (see FIG. 3).

  When normal operation is performed in this state, two sets of three-phase inverters composed of a plurality of inverter units convert the DC power supplied from the DC input buses P and N into three-phase AC power and output AC. It can be supplied to the AC motor M connected to the buses U, V, W and driven.

  4 and 5 show details of a state in which the unit tray UT containing the inverter unit (U1) is attached to the stack ST.

  A movable disconnect terminal MDA of the main circuit disconnect section MDS, a movable disconnect confirmation terminal SDA of the auxiliary circuit disconnect section SDS, and a ground disconnect terminal EA are disposed on the back of the unit tray UT, and the control circuit connector CNT is disposed on the front. And a handle HD.

  In a normal state, the unit tray UT is inserted into the stack ST until the movable disconnect terminals MDA, SDA, and EA are inserted and connected to the fixed disconnect terminals MDB, SDB, and EB of the disconnect sections provided on the stack ST side, respectively. At the connected position, the normal fixing bolt A having a short length shown in FIG. 6 is used to fix the fixed frame of the stack ST as shown in FIG.

  When a failure occurs, as shown in FIG. 5, the tray of the failed unit is disconnected from the main circuit disconnecting part MDS and the auxiliary circuit disconnecting part SDS by a distance L that is electrically safe enough. Pull out to the disconnect position. As a result, the failed inverter unit is disconnected from the external circuit. At this disconnection position, the long disconnection fixing bolt B shown in FIG. 6 is connected to the stack ST via the sleeve-shaped spacer S having the length L. If fixed to the fixed frame, the inverter unit U1 can be fixedly supported on the stack ST in a state in which the main circuit disconnecting part MDS and the auxiliary circuit disconnecting part SDS arranged on the back face are disconnected.

  In this state, since the monitoring device (not shown) can detect the failed unit by detecting the disconnection of the disconnection confirmation circuit DSC via the control circuit CTR, the operation command to the failed unit is stopped.

  Note that when the inverter unit U1 is inserted to the connection position, the ground circuit is also connected at the same time (see FIG. 4), so that electrical safety is ensured and countermeasures against common mode noise are also secured.

Next, a recovery operation when a failure or abnormality occurs in the power conversion apparatus of the present invention will be described.
(1) Fusing of fuse FP of DC input circuit Q1 and Q2 or Q3 and Q4 are turned on at the same time due to abnormal control signal or abnormal operation of semiconductor elements Q1 to Q4 of inverter circuit INV (see FIG. 2) In this case, since Q1 and Q2 or Q3 and Q4 short-circuit the DC circuit PN, a short-circuit current flows through the DC input circuit, and the fuse FP of this circuit is blown.

  When the fuse FP is blown, the blow alarm contact FPA is turned on, and an on signal is transmitted from the control circuit CTR to a separate monitoring device (not shown) via the control circuit cable.

  In this case, since the failed inverter circuit is disconnected from the DC buses P and N by the fuse FP, the monitoring device determines the ON detection signal of the fusing alarm contact FPA of the fuse FP and issues a stop command to the failed inverter unit. By giving an operation command to another healthy inverter unit and continuing the operation, the power conversion device can continue the operation without stopping.

Thereafter, the faulty inverter unit whose operation has been stopped is pulled out of the stack ST to a disconnection position separated by a predetermined distance L that is electrically safe when the normal fixing bolt A is removed and the disconnecting parts MDS and SDS are disconnected. At that position, the fixing bolt B for disconnection shown in FIG. 6 is fixed to the stack ST via the spacer S and temporarily held.
(2) Overcurrent of the DC input circuit In normal operation, the DC input circuit current detected by the current detector CTD is controlled so as not to exceed a predetermined set current. Therefore, if this current exceeds the set current, abnormal operation occurs. Therefore, the in-unit control circuit detects this and stops the semiconductor elements Q1 to Q4, and a separately provided monitoring device gives a stop command to the unit.

  If the semiconductor elements Q1 to Q4 are stopped and the abnormal current disappears, the inverter unit in which the abnormality has occurred is stopped, and a healthy operation command is given to another inverter unit to continue the operation.

  After that, the failed inverter unit whose operation has been stopped is pulled out to the disconnection position of the stack, fixed at this position with the fixing bolt B for disconnection, and the inverter unit is completely electrically separated from the external circuit to which the power source and the load are connected. Therefore, further safety of the apparatus is ensured.

In addition, if the abnormal current continues even if the semiconductor elements Q1 to Q4 are stopped, it is an uncontrollable abnormal state. Therefore, immediately after shutting off the DC power source connected to the DC buses P and N, the faulty inverter unit is stacked. Pull it out to the disconnect position, fix it, hold it temporarily, turn on the power again, and restart the operation with only the remaining healthy inverter unit.
(3) Fusing of the fuse FU of the AC output circuit When an abnormality such as a short circuit occurs in the AC load circuit, the fuse FU of the AC output circuit is blown. When the fuse FU is blown, the blow alarm contact FUA is turned on, and an ON signal is transmitted from the control circuit CTR to a separately provided monitoring device via the control circuit cable.

  In this case, since the failed inverter unit is disconnected from the AC output circuit, the monitoring device gives a stop command to the failed unit and gives an operation command to another healthy unit to continue the operation.

After that, the faulty unit whose operation has been stopped is pulled out to the disconnection position of the stack, the spacer S is inserted into the disconnection fixing bolt B, and fixed to the stack, and temporarily held. As a result, the auxiliary circuit is also separated, thereby further ensuring safety.
(4) Overcurrent of AC output circuit In normal operation, the current of the AC output circuit detected by the current detector CTA is controlled so as not to exceed a predetermined set current. If it exceeds, it is an abnormal operation, and the in-unit control circuit CTR and an external monitoring device provided separately detect this and give a stop command to the faulty inverter unit having an abnormality.

  As a result, when the semiconductor elements Q1 to Q4 of the inverter circuit INV in the unit are stopped and the abnormal current disappears, the monitoring device gives an operation command to another healthy power conversion device while giving a stop command to the failed unit. To continue driving.

  Thereafter, the faulty inverter unit whose operation has been stopped is pulled out to the disconnection position of the stack, and at this position, the spacer S is inserted into the disconnection fixing bolt B and fixed to the stack, and temporarily held. Thereby, since the unit is completely separated from the external circuit to which the power source and the load are connected, further safety is ensured.

  Further, if the abnormal current continues even if the semiconductor elements Q1 to Q4 are stopped, it is an abnormal state that cannot be controlled. Therefore, immediately after shutting off the DC power supply, the faulty unit is pulled out to the disconnection position and stacked with the disconnection fixing bolt B. After holding it temporarily, turn on the power and resume operation.

  According to this invention, each power conversion unit inserted into the stack can be fixed to the stack not only at the connection position where the disconnection portion in the stack is connected but also at the disconnection position where the disconnection portion is disconnected. If one of the conversion units fails, it is possible to continue operation with the remaining healthy power conversion units while temporarily holding the failed unit fixed to the stack at the disconnect position without pulling the failed unit out of the stack. Therefore, the failure can be recovered in a short time and no special space is required for storing the failed unit.

  The failed power conversion unit separated from the external circuit and temporarily held in the stack is repaired or replaced with a spare part when the operation of the power conversion device is stopped and becomes repairable. Like that.

  The present invention is most suitable for a power conversion device mounted on a ship or vehicle having a limited installation space.

  ST: Stack, U1, U2-W1, W2: Inverter unit (power conversion unit), MDS: Main circuit disconnection part, SDS: Auxiliary circuit disconnection part, A: Normal fixing bolt, B: Fixing bolt for disconnection, S: Spacer.

Claims (2)

The power conversion circuit is divided into a plurality of units, and each of the divided units is assembled into a drawer-type tray to form a plurality of power conversion units. Each power conversion unit is stored in a stackable manner, and each power conversion is stored. In the power conversion device provided between the unit and the stack by providing a disconnecting portion for interrupting the connection between the internal circuit and the external circuit of the unit in accordance with the insertion and removal of the power conversion unit,
At the connection position where each power conversion unit is inserted into the stack and the disconnection portion is in a connected state, the stack is obtained by maintaining the connection state of the disconnection portion with the normal fixing bolt having a short length. At the disconnection position where each power conversion unit is pulled out of the stack and the disconnection part is disconnected, the long disconnector fixing bolts each having a spacer for maintaining the disconnection interval of the disconnection part are used. A power conversion device, wherein a power conversion unit is fixed to the stack while maintaining a disconnection state of the disconnection portion. The power conversion device according to claim 1, wherein a disconnection confirmation unit that confirms a connection state is provided in the disconnection unit.

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