CN217741316U - Cooler power supply device and transformer system - Google Patents

Abstract

The application relates to a cooler power supply device and a transformer system. The cooler power supply device comprises a main power supply circuit, wherein the main power supply circuit comprises an air switch, a first relay and a first normally closed contact, and the first relay and the first normally closed contact are connected with the air switch in series; and the air switch is used for controlling the on-off of the main power supply circuit. The device can reduce the operation risk.

Description

Cooler power supply device and transformer system

Technical Field

The application relates to the technical field of electric power, in particular to a cooler power supply device and a transformer system.

Background

The start and stop of a cooler of a transformer in a nuclear power plant can be influenced by power transmission and power failure of the transformer, the cooler is started when the transformer transmits power, and the cooler is stopped when the transformer fails.

At present, the isolation disconnecting link needs to be manually operated so as to supply power or stop supplying power to the transformer, and then the start and stop of the cooler are controlled according to the state of the extended point intermediate relay. For example, when the isolation switch is switched on, the extension point intermediate relay loses power, so that the cooler is started; when the isolation disconnecting link is opened, the extended point intermediate relay is electrified, so that the cooler stops.

However, when the isolation switch or the extended point intermediate relay is touched by mistake by a person to cause malfunction, the current operation mode has operation risk.

SUMMERY OF THE UTILITY MODEL

In view of the above, it is desirable to provide a cooler power supply device and a transformer system capable of reducing an operation risk.

In a first aspect, the present application provides a cooler power supply. The cooler power supply device comprises a main power supply circuit, wherein the main power supply circuit comprises an air switch, a first relay and a first normally closed contact, and the first relay, the first normally closed contact and the air switch are connected in series;

the air switch is used for controlling the on-off of the main power supply circuit.

In one embodiment, the power supply device of the cooler further comprises a slave power supply circuit, and the master power supply circuit and the slave power supply circuit are identical in structure.

In one embodiment, the main power supply circuit further includes a second relay connected in series with the air switch, the second relay being connected in parallel with the first relay.

In one embodiment, the main power supply circuit further comprises a first normally open contact connected in series with the first relay and the first normally closed contact, and the second relay is used for controlling the opening and closing of the first normally open contact.

In one embodiment, the main power supply circuit further comprises a second normally open contact and a main power source monitoring device, one end of the second normally open contact is connected with the main power source monitoring device, the other end of the second normally open contact is connected with the second relay, and the main power source monitoring device is used for controlling the second normally open contact to open and close.

In one embodiment, the main power supply circuit further comprises a third normally open contact, and the first relay is used for controlling the opening and closing of the third normally open contact so as to control the on-off of the main power supply circuit.

In one embodiment, the master power supply circuit is electrically interlocked with the slave power supply circuit.

In one embodiment, the main power supply circuit is a three-phase power supply circuit, and the main power supply monitoring device is a three-phase power supply state monitoring device.

In one embodiment, the main power supply circuit further comprises an isolation circuit, and the isolation circuit is arranged between the main power supply monitoring device and the second normally open contact.

In a second aspect, the present application further provides a transformer system. The transformer system comprises a transformer, a cooler connected to the transformer and a cooler power supply as in any one of the above.

According to the cooler power supply device and the transformer system, the on-off of the main power supply circuit is directly controlled by the air switch, so that the start and stop of the cooler are controlled, and the condition that the expansion point intermediate relay controls the start and stop of the cooler in the traditional technology is eliminated. That is to say, more traditional technique indirectly according to the mode that opens and stop of isolation switch and the intermediate relay that expands the point control cooler, the state of isolation switch and the intermediate relay that expands the point in this application can not influence opening and stopping of cooler. Therefore, the power supply unit of cooler that this application provided is under the condition that artificial mistake touched isolation switch or expanded point intermediate relay and takes place the malfunction, opening of cooler is not influenced, has solved the problem that the operation mode has the operation risk among the traditional technology, has reduced the operation risk.

Drawings

FIG. 1 is a schematic circuit diagram of a prior art extended-point intermediate relay;

FIG. 2 is a schematic diagram of a power supply circuit of a conventional chiller;

FIG. 3 is a schematic diagram of a main power circuit of a conventional chiller;

FIG. 4 is a circuit schematic of the main power supply circuit of the present application;

fig. 5 is a circuit schematic diagram of a slave power supply circuit in the present application.

Description of the reference numerals:

101-disconnecting knife switch auxiliary contact, 102-ZJ1 relay, 201-ZJ1 normally open contact, 202-K relay, 301-Q1 switch, 302-power monitoring device, 303-KMS1 normally open contact, 304-isolating circuit, 305-Q2 switch, 306-KV1 normally open contact, 307-K1 relay, 308-K1 normally open contact, 309-KMS2 normally closed contact, 310-KMS1 relay, 311-K normally closed contact, 401-emergency switch, 402-main power monitoring device, 403-third normally open contact, 404-isolating circuit, 405-air switch, 406-second normally open contact, 407-second relay, 408-first normally open contact, 409-first normally closed contact, 410-first relay, 501-emergency switch, 502-slave power detection device, 503-third normally open contact, 504-isolating circuit, 505-air switch, 506-second normally open contact, 507-second normally open relay, 508-first contact, 509-first contact, 510-first normally closed relay.

Detailed Description

The numbering of the components as such, e.g., "first", "second", etc., is used herein only to distinguish the objects as described, and does not have any sequential or technical meaning. The term "connected" and "coupled" when used in this application, unless otherwise indicated, includes both direct and indirect connections (couplings). In the description of the present application, it is to be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", and the like, indicate orientations or positional relationships based on those shown in the drawings, and are used only for convenience in describing the present application and for simplicity in description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed in a particular orientation, and be operated, and thus, are not to be considered as limiting the present application.

In this application, unless expressly stated or limited otherwise, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through intervening media. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature "under," "beneath," and "under" a second feature may be directly under or obliquely under the second feature, or may simply mean that the first feature is at a lesser elevation than the second feature.

In order to make the objects, technical solutions and advantages of the present application more clearly understood, the present application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.

The transformer controls the oil temperature through the cooler. At present, the start and stop of a cooler of a transformer in a nuclear power plant can be influenced by power transmission and power failure of the transformer, the cooler starts to work when the transformer transmits power, and the cooler stops working when the transformer fails.

Fig. 1 to 3 illustrate the principle of the operation of the cooler in the prior art, and the prior art will be described with reference to fig. 1 to 3.

Fig. 1 is a schematic circuit diagram of a prior art extended-point intermediate relay. Wherein, the isolation switch auxiliary contact 101 is a normally closed contact. When the isolation switch is manually operated to be switched off, the transformer stops power transmission, and the auxiliary contact 101 of the isolation switch is closed; when the isolation switch is manually operated to be switched on, power is supplied to the transformer, and the auxiliary contact 101 of the isolation switch is disconnected.

Further, since the auxiliary isolation switch contact 101 is connected in series with the ZJ1 relay 102, when the isolation switch is opened, the auxiliary isolation switch contact 101 is closed, and the ZJ1 relay 102 is energized; when the isolation knife switch is switched on, the isolation knife switch auxiliary contact 101 is disconnected, and the ZJ1 relay 102 loses power. Among them, the ZJ1 relay 102 is a spread point intermediate relay.

Fig. 2 is a schematic diagram of a power supply switching circuit of a cooler in the prior art. The chiller power supply throw circuit includes a ZJ1 normally open contact 201 and a K relay 202. The power on or off of the ZJ1 relay 102 controls the opening or closing of the ZJ1 normally open contact 201. That is, the normally open ZJ1 contact 201 is closed by the power-on of the ZJ1 relay 102, and the normally open ZJ1 contact 201 is opened by the power-off of the ZJ1 relay 102. Further, since the ZJ1 normally open contact 201 and the K relay 202 are connected in series, when the ZJ1 normally open contact 201 is closed, the K relay 202 is powered; when the normally open contact 201 of ZJ1 is open, the K relay 202 is de-energized.

Fig. 3 is a schematic diagram of a main power circuit of a conventional cooler. As shown in fig. 3, the Q1 switch 301 and the Q3 switch 305 need to be closed by human operation, and the power-on or power-off of the K1 relay 307 controls the closing or opening of the K1 normally open contact 308. When the power monitoring device 302 monitors that the power of the cooler is normal, the KV1 normally open contact 306 is closed, and then the K1 relay 307 is energized, so that the K1 normally open contact 308 is closed due to the energization of the K1 relay 307.

The KMS2 normally closed contact is controlled by a slave power circuit (not shown in the figure) of the cooler, and it is understood that the master power circuit and the slave power circuit of the cooler are operated mutually exclusively, and generally only one of the master power circuit and the slave power circuit is required to be used as a power supply to supply power to the cooler. Specifically, the KMS1 normally closed contact 309 is controlled by the operating state of the slave power supply circuit, and when the slave power supply circuit is not required as the power supplier of the cooler, the KMS1 normally closed contact 309 is closed, and when the slave power supply circuit is required as the power supplier of the cooler, the KMS1 normally closed contact 309 is opened. That is, when the main power circuit of the cooler is required as the power supply side of the cooler, the KMS1 normally closed contact 309 is closed.

With reference to fig. 2, the K normally closed contact 311 is controlled by the K relay 202 of fig. 2. Specifically, when the K relay 202 is powered on, the K normally closed contact 311 is opened; when the K relay 202 loses power, the K normally closed contact 311 is closed.

The KMS1 normally open contact 303 is controlled by a KMS1 relay 310 relay. Specifically, when the KMS1 relay 310 is powered on, the KMS1 normally open contact 303 is closed; when the KMS1 relay 310 loses power, the KMS1 normally open contact 303 opens.

Taking the main power circuit as an example of a power supply for the cooler, in conjunction with fig. 1 to 3, when the isolating switch is manually operated to close, power is supplied to the transformer, and the cooler needs to be started in such a case. Specifically, the isolation switch auxiliary contact 101 is opened, the ZJ1 relay 102 is de-energized, and further the ZJ1 normally open contact 201 is opened, the K relay 202 is de-energized, and thus the K normally closed contact 311 is closed. Q1 switch 301 and Q3 switch 305 are in the closure state all the time, and under normal conditions, KV1 normally open contact 306 is closed, and then K1 relay 307 gets electric, and K1 normally open contact 308 is closed, and KMS1 normally closed contact 309 is closed, thereby KMS1 relay 310 gets electric because the switching on of place return circuit. Further, the KMS1 normally open contact 303 is closed by the power-on of the KMS1 relay 310, so that the main power circuit of the cooler is activated to supply power to the cooler, i.e., the cooler is activated.

When the isolating knife switch is manually operated to be closed, the power supply of the transformer is stopped, and in this case, the cooler also needs to stop working. Specifically, the isolation switch auxiliary contact 101 is closed, the ZJ1 relay 102 is energized, and then the ZJ1 normally open contact 201 is closed, the K relay 202 is energized, and thus the K normally closed contact 311 is opened. The KMS1 relay 310 is also de-energized due to the opening of the circuit in which it is located. Further, the KMS1 normally open contact 303 is opened due to a loss of power to the KMS1 relay 310, so that the main power supply circuit of the cooler stops operating, that is, the cooler stops operating.

The principle is the same when the cooler needs to be powered from the power circuit, and the details are not repeated here. That is, in the conventional art, the cooler is fully stopped by electrically interlocking between the opening and closing states of the extended intermediate relay (i.e., the ZJ1 relay 102) and the isolation switch of the transformer. Specifically, the isolation switch needs to be manually operated to supply power to the transformer or stop the supply of power, so as to control the start and stop of the cooler according to the state of the extended-point intermediate relay. However, when the cooler is normally operated, if the isolating switch or the extended-point intermediate relay (i.e., the ZJ1 relay 102) is touched by mistake by a person, the cooler stops operating, so that the oil temperature of the transformer cannot be controlled, the oil temperature of the transformer rises, and the operation risk is increased. Therefore, the operation mode in the conventional art has an operation risk.

Specifically, the cooler is normally started and in a working state, but when the isolating disconnecting link is accidentally touched by a person or the ZJ1 relay 102 malfunctions to be powered on, the normally open contact 201 of the ZJ1 is closed, and further the K relay 202 is powered on, so that the normally closed contact 311 of the K is opened. The KMS1 relay 310 is also powered down due to the disconnection of the loop, the KMS1 normally open contact is opened, the cooler stops working abnormally, and no alarm is given. Therefore, the oil temperature of the transformer cannot be controlled, and the operation risk of the transformer is increased.

In view of the above, it is necessary to provide a cooler power supply device that reduces operational risks in view of the above technical problems.

Fig. 4 is a schematic circuit diagram of a main power supply circuit in the present application, and as shown in fig. 4, the cooler power supply device 400 in the present application includes the main power supply circuit, the main power supply circuit includes an air switch 405, a first relay 410, and a first normally closed contact 409, the first relay 410, the first normally closed contact 409 are connected in series with the air switch 405, and the air switch 405 is used to control on/off of the main power supply circuit.

That is to say, the power supply device of the cooler provided by the application directly controls the on-off of the main power supply circuit through the air switch 405, and then controls the start and stop of the cooler, thereby eliminating the situation that the start and stop of the cooler is controlled through the extended point intermediate relay in the traditional technology. That is to say, more traditional technique indirectly according to the mode that opens and stops of isolation switch and spread some auxiliary relay control cooler, the state of isolation switch and spread some auxiliary relay can not influence opening and stopping of cooler in this application. Therefore, the power supply unit of cooler that this application provided is under the condition that artificial mistake touched isolation switch or expanded point intermediate relay and takes place the malfunction, opening of cooler is not influenced, has solved the problem that the operation mode has the operation risk among the traditional technology, has reduced the operation risk.

In this embodiment, the cooler power supply device further includes a slave power supply circuit, and the master power supply circuit and the slave power supply circuit have the same structure. It will be appreciated that both the master and slave power supply circuits may power the chiller, thereby controlling the start or stop of the chiller. The main power supply circuit and the slave power supply circuit work mutually exclusive, and one way to realize the mutual exclusion operation is that when the main power supply circuit is abnormal or has a fault, the slave power supply circuit supplies power for the cooler, and when the main power supply circuit recovers to be normal, the main power supply circuit is switched back to supply power for the cooler. The main power supply circuit and the auxiliary power supply circuit improve the stability of the power supply device of the cooler, and the problems that the cooler cannot normally supply power and the running risk is increased are solved.

In the present embodiment, the main power supply circuit further includes a second relay 407, the second relay 407 being connected in series with the air switch 405, the second relay 407 being connected in parallel with the first relay 410.

In this embodiment, the main power supply circuit further includes a first normally open contact 408, the first normally open contact 408 is connected in series with a first relay 410 and a first normally closed contact 409, and the second relay 407 is configured to control opening and closing of the first normally open contact 408. Specifically, when the second relay 407 is powered on, the first normally open contact 408 is controlled to be closed, and when the second relay 407 is powered off, the first normally open contact 408 is controlled to be opened.

In this embodiment, the main power supply circuit further includes a second normally-open contact 406 and a main power source monitoring device 402, one end of the second normally-open contact 406 is connected to the main power source monitoring device 402, the other end of the second normally-open contact 406 is connected to the second relay, and the main power source monitoring device 402 is configured to control opening and closing of the second normally-open contact 406. Specifically, the main power monitoring device 402 controls the second normally open contact 406 to be closed under the normal condition of the main power, and controls the second normally open contact 406 to be opened under the abnormal condition of the main power.

In this embodiment, the main power supply circuit further includes a third normally open contact 403, and the first relay 410 is configured to control opening and closing of the third normally open contact 403, so as to control on and off of the main power supply circuit.

In this embodiment, the master power supply circuit and the slave power supply circuit are electrically interlocked with each other. Fig. 5 is a circuit schematic diagram of a slave power supply circuit in the present application. The slave power supply circuit comprises an emergency switch 501, a slave power supply detection device 502, a third normally open contact 503, an isolation circuit 504, an air switch 505, a second normally open contact 506, a second relay 507, a first normally open contact 508, a first normally closed contact 509 and a first relay 510. As shown in fig. 5, the slave power supply circuit and the master power supply circuit have the same structure, and are not described again here.

Generally, only one of the master power supply circuit and the slave power supply circuit is required to be used as a power supply source to supply power to the cooler, and the electrical interlock is used for realizing the mutual exclusion work of the master power supply circuit and the slave power supply circuit. The first normally closed contact 409 of the master power supply circuit is controlled by the first relay 510 in the slave power supply circuit, specifically, when the slave power supply circuit is closed or the slave power supply circuit is required to be used as a power supply party of the cooler, the first relay 510 is powered on, and then the first normally closed contact 409 is disconnected, so that the master power supply circuit cannot be closed and supplies power to the cooler, and vice versa. The first normally closed contact 509 of the slave power supply circuit is controlled by the first relay 410 in the master power supply circuit, and specifically, when the master power supply circuit is closed or the master power supply circuit is required to be used as a power supply party of the cooler, the first relay 410 is powered on, and further the first normally closed contact 509 is disconnected, so that the slave power supply circuit cannot be closed and supplies power to the cooler, and vice versa. Therefore, the main power supply circuit and the auxiliary power supply circuit are electrically interlocked, so that the stability of the cooler power supply device can be improved, and abnormal cooler power supply caused by the simultaneous starting of the main power supply circuit and the auxiliary power supply circuit is avoided.

It will be appreciated that the first normally closed contact 409 is closed by default when the main power circuit is acting as the power supply for the cooler. When the slave power supply circuit is used as a power supply of the cooler, the first normally closed contact 509 is closed by default.

In this embodiment, the main power supply circuit is a three-phase power supply circuit, and the main power supply monitoring device 402 is a three-phase power supply state monitoring device. Wherein 1L 1-1L 3 respectively represent the ground wire, the zero wire and the live wire of the first section power supply and the second section power supply. The same applies to the power supply circuit, and will not be described herein.

In this embodiment, the main power supply circuit further includes an isolation circuit 404, and the isolation circuit 404 is disposed between the main power monitoring device 402 and the second normally open contact 406. The isolation circuit 404 is used for electrical isolation to reduce interference between different circuits, thereby improving the operating efficiency of the power supply of the cooler.

The main power supply circuit further comprises an emergency switch 401, wherein the emergency switch 401 is used for cutting off the power supply of the cooler in an emergency, and the emergency switch 401 is normally closed by human operation to emergently stop the operation of the cooler, so that the safety of the power supply device of the cooler is improved.

Here, the main power supply circuit is taken as a power supply side of the cooler. Referring to fig. 4, the emergency switch is closed by default, and the emergency switch 401 is normally closed by a human operation. The primary power monitoring device 402 controls the second normally open contact 406 to close under normal primary power conditions.

When the air switch 405 is closed, the circuit in which the second relay 407 is located is turned on and energized, and the first normally open contact 408 is closed. The first normally closed contact 409 is closed by default, so that the circuit in which the first relay 410 is located is conductive and powered. Since the first relay 410 is energized, the third normally open contact 403 is closed, so that the main power supply circuit supplies power to the cooler, and the cooler is started to operate.

When the air switch 405 is opened, the circuit in which the second relay 407 is located is opened and loses power, and the first normally open contact 408 is opened, so that the circuit in which the first relay 410 is located is opened and loses power. Due to the loss of power of the first relay 410, the third normally open contact 403 is opened, so that the main power supply circuit stops supplying power to the cooler, and the cooler stops working.

The cooler power supply device in the application is in short circuit with the K normally closed contact 311 of the main power circuit in the traditional technology, and the same process is carried out from the power circuit, and the details are not repeated here. That is, the present application provides a cooler power supply device that eliminates the K normally closed contact 311 in the main and slave power supply circuits of the cooler in the conventional art, and the circuit of the extended-point intermediate relay and the cooler power supply input circuit in the conventional art still remain the same. Therefore, even if the isolating disconnecting link or the extended point intermediate relay is touched by people by mistake to cause misoperation, the working state of the main power supply circuit or the auxiliary power supply circuit cannot be influenced.

Further, the power supply device for the cooler in the present application can reuse the elements in the conventional art. For example, emergency switch 401 multiplexes Q1 switch 301, main power source monitoring device 402 multiplexes power source monitoring device 302, third normally open contact 403 multiplexes KMS1 normally open contact 303, isolation circuit 404 multiplexes isolation circuit 304, air switch 405 multiplexes Q2 switch 305, second normally open contact 406 multiplexes KV1 normally open contact 306, second relay 407 multiplexes K1 relay 307, first normally open contact 408 multiplexes K1 normally open contact 308, first normally closed contact 409 multiplexes KMS2 normally closed contact 309, and first relay 410 multiplexes KMS1 relay 310.

To sum up, the cooler power supply unit that this application provided optimizes through the power supply circuit to the cooler among the traditional art, cancels the cooler power supply and drops into the electric interlocking between the power supply circuit of circuit and cooler to prevent that the mistake from touching the condition of the single trouble that isolation switch or spread a little intermediate relay lead to, avoid causing the problem of cooler stop work, reduce the operation risk, stability when increasing the transformer operation.

Moreover, the cooler power supply device optimizes the design on the premise of not violating relevant regulations and ensuring that all original other functions are unchanged, the circuit is simple to realize, new equipment is not required, only the K normally closed contact 311 in the traditional technology is required to be cancelled, the transformation cost can be reduced, and the practicability is high.

Based on the same utility model conception, the embodiment of the application also provides a transformer system. The implementation scheme for solving the problem provided by the transformer system is similar to the implementation scheme recorded in the device, and is not described herein again.

The various modules in the chiller power supply described above may be implemented in whole or in part by software, hardware, and combinations thereof. The modules can be embedded in a hardware form or independent of a processor in the computer device, and can also be stored in a memory in the computer device in a software form, so that the processor can call and execute operations corresponding to the modules.

It should be noted that, the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data for analysis, stored data, presented data, etc.) referred to in the present application are information and data authorized by the user or sufficiently authorized by each party.

The technical features of the above embodiments can be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the above embodiments are not described, but should be considered as the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present application. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, and these are all within the scope of protection of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims (8)

1. A cooler power supply device is characterized by comprising a main power supply circuit, wherein the main power supply circuit comprises an air switch, a first relay and a first normally closed contact, and the first relay and the first normally closed contact are connected with the air switch in series;

the air switch is used for controlling the on-off of the main power supply circuit;

the main power supply circuit further comprises a second relay and a first normally-open contact, the first normally-open contact is connected with the first relay and the first normally-closed contact in series, the second relay is connected with the air switch in series, the second relay is connected with the first relay, the first normally-closed contact is connected with the first normally-open contact in parallel, and the second relay is used for controlling opening and closing of the first normally-open contact.

2. The chiller power supply of claim 1, further comprising a slave power supply circuit, said master power supply circuit and said slave power supply circuit being identical in construction.

3. The power supply device for the cooler according to claim 1, wherein the main power supply circuit further comprises a second normally open contact and a main power source monitoring device, one end of the second normally open contact is connected with the main power source monitoring device, the other end of the second normally open contact is connected with the second relay, and the main power source monitoring device is used for controlling the opening and closing of the second normally open contact.

4. A power supply device for cooler according to any one of claims 1-3, characterized in that said main power supply circuit further comprises a third normally open contact, and said first relay is used for controlling the opening and closing of said third normally open contact to control the on and off of said main power supply circuit.

5. The chiller power supply of claim 2, wherein the master power supply circuit is electrically interlocked with the slave power supply circuit.

6. A chiller power supply as set forth in claim 3 wherein said primary power supply circuit is a three-phase power supply circuit and said primary power supply monitoring device is a three-phase power status monitoring device.

7. A chiller power supply as set forth in claim 3 wherein said main power supply circuit further comprises an isolation circuit disposed between said main power monitoring device and said second normally open contact.

8. Transformer system, characterized in that it comprises a transformer, a cooler connected to the transformer and a cooler power supply device according to any of claims 1-7.

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