JP2013059152A - Discrete bypass system parallel uninterruptible power supply system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a discrete bypass system parallel UPS system which can supply power from a sound UPS for some loads upon occurrence of failure in one or more UPS.SOLUTION: In the discrete bypass system parallel uninterruptible power supply system configured to perform parallel operation of a plurality of uninterruptible power supplies, loads are sectioned into most important loads 30 and important loads 31. Power is normally supplied to all loads by operating the outputs from the inverters 5 of uninterruptible power supplies 1 in parallel. When any of the uninterruptible power supplies 1 is paralleled off due to failure and the remaining uninterruptible power supplies are overloaded, output from the inverter 5 of a sound uninterruptible power supply 1 is supplied to the most important loads 30 according to a predetermined control flow, and power is supplied to the important loads 31 by the bypass power supply 15.

Description

  The present invention relates to an individual bypass type parallel uninterruptible power supply system that operates in parallel a plurality of uninterruptible power supply devices each having a bypass circuit as a backup power source during a power failure.

  Conventionally, an uninterruptible power supply (hereinafter simply referred to as UPS) has been used as a power source for an important load such as a computer that does not allow an instantaneous power outage. Further, during normal operation and inspection for 365 days, When continuous power supply by a UPS power supply is required, a parallel UPS system configured by operating a plurality of UPSs in parallel is used as a highly reliable system.

  In recent parallel UPS systems, in order to achieve continuity of load power supply as much as possible even in the case of maintenance inspection and failure of the bypass switching circuit, in order to achieve uninterrupted switching between the bypass circuit and this bypass circuit in each UPS. An individual bypass parallel UPS system having an uninterruptible switching circuit is employed.

  The individual bypass parallel UPS system is generally used as a large-capacity UPS system by operating multiple UPSs in parallel when the capacity of a single UPS is insufficient, but the actual load capacity is limited to multiple units. If one of the configured UPSs is less than the capacity that has failed or stopped (that is, the capacity that is one less than the total capacity of multiple UPSs), redundancy is added and the individual redundant parallel redundant UPS It is also configured as a system (for example, see Patent Document 1).

JP 2007-189861 A (general)

  The individual bypass parallel UPS system configured as described above is configured by operating a plurality of UPSs in parallel. In a parallel UPS system that does not have redundancy in consideration of economic efficiency, or in a parallel UPS system that has lost parallel redundancy due to a UPS failure, if one or some UPS fails, the remaining sound The UPS detects the overload as the load capacity exceeds the rated capacity. Then, the UPS that has failed first and the healthy UPS are simultaneously switched to power feeding by the bypass circuit, and load power feeding is continued.

  However, since this bypass power supply is a power supply by a bypass circuit of a commercial power supply, there is no backup function against a power failure or an instantaneous voltage drop, and if these occur, the load will be stopped. In other words, a healthy UPS switches over to the bypass circuit power supply by the commercial power supply due to overloading due to disconnection of the faulty machine, even though its own UPS is not faulty. When power supply fluctuations such as the above occur, there is a problem that the load power supply is hindered.

  The present invention has been made to solve the above-described problems, and even if a failure occurs in one or more UPSs, power can be supplied from a sound UPS to some loads. An object of the present invention is to provide a separate bypass parallel UPS system.

  In order to achieve the above object, an individual bypass type parallel uninterruptible power supply system of the present invention includes a forward converter that converts an alternating current input from a commercial alternating current power source into a direct current, and a direct current output from the forward converter. And an inverter that converts DC to AC again and outputs, a storage battery that supplies DC power to the inverter when the commercial AC power supply fails, and power supply to a load by the output of the inverter In an individual bypass type parallel uninterruptible power supply system configured to operate in parallel a plurality of uninterruptible power supply units comprising an uninterruptible switching circuit for switching between power supply to a load by a bypass power supply. Divide the load into the most important load and the important load. In normal operation, the output of the reverse converter is operated in parallel to supply power to the most important load and the important load. When the remaining healthy power failure power supply device is overloaded, the most important load is fed with the output of the healthy uninterruptible power supply reverse converter according to a predetermined control flow, The important load is characterized in that power is supplied by the bypass power source.

  According to the present invention, it is possible to provide an individual bypass parallel UPS system capable of supplying power from a sound UPS to a part of loads even if a failure occurs in one or more UPSs. .

1 is a circuit configuration diagram of an individual bypass parallel UPS system according to the present invention. The power supply route figure (1) of the individual bypass system parallel UPS system concerning the present invention. The power supply route figure of an individual bypass system parallel UPS system concerning the present invention (2). The power supply route figure (3) of the individual bypass system parallel UPS system concerning the present invention. The operation | movement flowchart of the separate bypass system parallel UPS system which concerns on this invention. The power supply route figure (4) of the individual bypass system parallel UPS system concerning the present invention. The operation | movement flowchart of the separate bypass system parallel UPS system which concerns on the modification of this invention. The electric power feeding route figure of the individual bypass system parallel UPS system which concerns on the modification of this invention.

  An embodiment of the present invention will be described below with reference to FIG.

  FIG. 1 is a block diagram showing an example of an individual bypass parallel UPS system according to the present invention. FIG. 1 shows an example including three UPSs, UPS1A (No1UPS), UPS1B (No2UPS), and UPS1C (No3UPS).

  Each of UPS 1A, 1B and 1C is supplied with AC voltage from commercial power supplies 2A, 2B and 2C, and converted into DC voltage by forward converters 4A, 4B and 4C via AC input switching 3A, 3B and 3C, respectively. Further, a stable AC voltage is obtained through the switches 7A, 7B, and 7C provided in the non-instantaneous switching circuits 6A, 6B, and 6C by being reversely converted into AC again by the inverters 5A, 5B, and 5C. Is configured to output. The forward converters 4A, 4B, and 4C store DC energy in the storage batteries 12A, 12B, and 12C via the DC switches 8A, 8B, and 8C, respectively.

  For example, when a power failure occurs in the commercial power supply 2A, AC power is output by supplying the DC energy of the storage battery 12A to the reverse converter 6A. Similarly, when a power failure occurs in the commercial power supplies 2B and 2C, the operation using the storage batteries 12B and 12C is performed.

  Further, in order to continuously output alternating current even if a failure occurs in the forward converters 4A, 4B, 4C or the reverse converters 5A, 5B, 5C, it is different from the commercial power supplies 2A, 2B, 2C. The AC voltage of the bypass power supplies 15A, 15B and 15C is supplied from the bypass input switch 11A and the uninterruptible switching circuit 6A. The parallel circuit of the switch 9A and the semiconductor switch 10A, the bypass input switch 11B and the uninterruptible switching Via a parallel circuit of the switch 9B and the semiconductor switch 10B provided in the circuit 6B, a bypass input switch 11C and a parallel circuit of the switch 9C and the semiconductor switch 10C provided in the uninterruptible switching circuit 6C, respectively. The UPS 1A, the UPS 1B, and the UPS 1C are configured to output the respective outputs. In other words, power can be supplied from the bypass circuit by the bypass power supply.

  The outputs of UPS 1A, UPS 1B, and UPS 1C are given to a parallel output panel 20 provided in common in the entire system, each of which is branched into two, one of which is connected to the most important load side parallel switch 21A, 21B, 21C, respectively. To the most important load parallel bus 23, and the other is connected to the important load parallel bus 24 via the important load side parallel switches 22A, 22B, 22C. Power is supplied from the most important load parallel bus 23 to the most important load 30 via the AC output switch 25. In addition, the important load 31 is supplied with power from the important load parallel bus 24 via the AC output switch 26. The load currents of the most important load 30 and the important load 31 are detected by load current detectors 27 and 28, respectively, and are supplied to the operation control device 40. The operation control device 40 performs operation control related to the entire system of the UPS 1A, UPS 1B and UPS 1C and the parallel output panel 20.

  Next, the operation will be described. In the individual bypass parallel UPS system composed of three UPSs shown in FIG. 1, when all UPSs are healthy, each UPS 1A, 1B, 1C is a forward converter 4A as shown in the power supply route diagram of FIG. 4B and 4C and the UPS output through the inverse converters 5A, 5B and 5C are supplied to the parallel output board 20, and the parallel output board 20 uses parallel switches 21A and 22A for UPS1A and parallel switches for UPS2A. 21B, 22B and all the parallel switches 21C, 22C for UPS1C are turned on, and power is supplied to the most important load 30 and the important load 31 with the three UPS outputs connected in parallel with the parallel buses 23, 24, respectively. To do.

  Assume that the UPS 1A fails in the power supply state of the power supply route diagram shown in FIG. When the UPS 1A detects a failure, the UPS 1A stops the operation of the forward converter 4A and the inverse converter 5A (gate block), stops the output of the UPS 1A, and disconnects from the parallel operation state. However, at this time, the converter-side switch 7A of the UPS 1A and the parallel switches 21A, 22A of the parallel output board 21 remain in the input state.

  In the power supply state shown in FIG. 2, if parallel redundancy is established, the most important load 30 and the important load 31 have two remaining healthy UPS 1B and UPS 1C as shown in the power supply route diagram of FIG. The UPS output (outputs of the inverse converters 5B and 5C) by the parallel operation is continuously supplied.

  However, in the power supply state shown in FIG. 2, when parallel redundancy is not established, if one UPS fails and is disconnected from parallel operation, the remaining healthy UPS has a load capacity of the rated capacity. Thus, an overload is detected. If a healthy UPS detects an overload, it will not be possible to continue power supply to the load by UPS output, and both UPS and sound UPS that have been faulted first and disconnected from parallel operation will be fed to the power by the bypass circuit without interruption. The load power feeding is continued by switching by.

  In the power supply route diagram of FIG. 4, after the UPS 1A fails in the power supply state of FIG. 2 and is disconnected from the parallel operation, the remaining two UPS 1B and 1C also detect overload, The UPS is switched to bypass power feeding and load power feeding is continued.

  As described above, when the power supply to the bypass power supplies 15A, 15B, and 15C has a power failure or an instantaneous voltage drop while the load power supply is being continued through the bypass path shown in FIG. Become.

  For this reason, in this embodiment, once all UPS 1A, 1B, 1C are switched to the power supply from bypass power supplies 15A, 15B, 15C, if the predetermined switching condition is satisfied, the most important load 30 is set. Switch to UPS output power supply again. This method will be described below with reference to the flowchart shown in FIG. 5 and the power supply route diagram of FIG.

  FIG. 5 is an operation flowchart of the individual bypass parallel UPS system according to the present invention. This flowchart is a flowchart in the case where the three UPSs and the operation control device 40 operate while exchanging signals in FIG. 1 and there is no parallel redundancy as a system.

  First, let us consider a state in which UPS output power supply is being performed by parallel operation of three UPS units (step ST1). This state corresponds to the power supply route diagram shown in FIG. In this state, for example, when UPS 1A fails (step ST2), UPS 1A stops and disconnects from parallel operation (step ST2). And since there is no parallel redundancy as a system, both UPS1B and UPS1C detect an overload (step ST4). Then, in order to continue the load power supply, the three UPSs are switched to power supply from the bypass power supply all at once (step ST5). This state corresponds to the power supply route diagram shown in FIG.

  Next, it is determined whether or not the load capacity of the most important load 30 is equal to or less than the sum of capacities of UPS1B and UPS1C, which are healthy UPSs (step ST6). At this time, the detection value of the load current detector 27 is used. If the determination in step ST6 is YES, it is determined whether or not the load capacity of the important load 31 is equal to or less than the capacity of the UPS 1A that is a failed UPS (step ST7). At this time, the detection value of the load current detector 28 is used. If the determination in step ST7 is YES, the parallel switch 21A is opened and the UPS 1A is disconnected from the most important load bus 23 (step ST8). If NO in step ST6 or step ST7, the bypass power supply shown in the power supply route diagram of FIG. 4 is continued (step ST9).

  Next, the parallel switches 22B and 22C are opened to disconnect the UPS 1B and UPS 1C from the important load bus 24 (step ST10). By the operation of step ST10, the overload of UPS1B and UPS1C is released (step ST11), the UPS1B and UPS1C uninterruptible switching circuits 6B and 6C operate, respectively, and UPS1B and UPS1C supply power to the most important load 30 in parallel. (Step ST12). At this time, the UPS 1A bypass power feeding is performed for the important load 31 (step ST13), and the power feeding route shown in FIG. 6 is achieved.

  Next, a modification of the present invention will be described with reference to FIGS.

  FIG. 7 is an operation flowchart of the individual bypass parallel UPS system according to the modification of the present invention. In this flowchart, when it is determined NO in step ST7 of the flowchart of FIG. 5, the process does not immediately go to step ST9, but it is confirmed in steps ST6A and ST7A whether the most important load 30 can be UPS-supplied again. I have to.

  That is, in step ST6A, it is determined whether or not the most important load capacity is equal to or less than the value obtained by subtracting one UPS capacity (for example, the capacity of UPS1B) from the sum of healthy UPS capacity. If this is YES, then in step ST7A It is determined whether the important load capacity is equal to or less than the capacity obtained by adding one UPS capacity (for example, the capacity of UPS1B) to the capacity of UPS1A that has failed.

  If either step ST6A or step ST7A is NO, bypass power feeding is continued in step ST9. If both are YES, step ST8A is performed in the same procedure as step ST8 to step ST13 in the flowchart of FIG. To step ST13A. As a result, the most important load 30 is supplied with UPS from the UPS 1C, and the important load 31 is supplied with power from the failed UPS 1A and healthy UPS 1B bypass circuit. In this way, the power supply route shown in FIG. 8 is achieved.

  As mentioned above, although the Example of this invention was described, these Examples are shown as an example and are not intending limiting the range of invention. The novel embodiment can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. This embodiment and its modifications are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  For example, in FIG. 1, the example of three UPSs has been described. However, it is obvious that the present invention is established if two or more UPSs are used.

  Further, although the most important load parallel bus 23 and the important load parallel bus 24 are provided in the parallel output panel 20 in FIG. 1, it is not always necessary to have such a configuration. For example, the most important load side parallel switch The system configuration may be such that 21A, the critical load side parallel switch 22A is accommodated in the panel of the UPS 1A.

  Further, in a system including four or more UPSs, even if NO is determined in step ST7A in FIG. 7, the operation of returning to step ST6A and further subtracting the capacity of one UPS is repeated to set the most important load 30. You may make it look for the combination which can be drive | operated by UPS output.

1A, 1B, 1C UPS
2A, 2B, 2C Commercial power supply 3A, 3B, 3C AC input switch 4A, 4B, 4C Forward converter 5A, 5B, 5C Reverse converter 6A, 6B, 6C Uninterruptible switching circuit 7A, 7B, 7C Converter side Switch 8A, 8B, 8C DC switch 9A, 9B, 9C Bypass switch 10A, 10B, 10C Bypass thyristor switch 11A, 11B, 11C Bypass input switch 12A, 12B, 12C Battery 15A, 15B, 15C For bypass Commercial power supply 20 Parallel output panel 21A, 21B, 21C Most important load side parallel switch 22A, 22B, 22C Important load side parallel switch 23 Most important load parallel bus 24 Important load parallel bus 25, 26 AC output switching 27, 28 Load current detector 30 Most important load 31 Important load

Claims (3)

A forward converter that converts alternating current input from a commercial alternating current power source into direct current,
DC converter from the forward converter as an input, an inverse converter that converts the DC to AC again and outputs,
A storage battery for supplying DC power to the inverter at the time of the commercial AC power failure;
An individual bypass system configured to operate in parallel a plurality of uninterruptible power supply units comprising an uninterruptible switching circuit for switching between power feeding to the load by the output of the inverse converter and power feeding to the load by a bypass power source. In the parallel uninterruptible power supply system,
Dividing the load into the most important load and the important load,
In normal operation, the output of the inverter is operated in parallel to supply the most important load and the important load,
When one of the uninterruptible power supply units fails and is disconnected from parallel operation, and the remaining healthy blackout power supply unit is overloaded,
According to a predetermined control flow,
The most important load is fed with the output of the healthy uninterruptible power supply inverter,
An individual bypass type parallel uninterruptible power supply system, wherein the important load is fed by the bypass power supply. A parallel output panel having two types of buses, a parallel bus for feeding the most important load and a parallel bus for feeding the important load;
Each power supply to the most important load and the important load can be selectively switched between power supply from the output of the inverter of the uninterruptible power supply or power supply by the bypass power supply. The individual bypass type parallel uninterruptible power supply system according to claim 1. The predetermined control flow is:
Once all the load power supply is moved to the bypass power supply,
An uninterruptible power supply that feeds power to the most important load by the output of an inverter according to the load capacity of the most important load and the important load and the capacity of each uninterruptible power supply, and bypass power feed to the important load 3. The individual bypass parallel uninterruptible power supply system according to claim 1 or 2, wherein an uninterruptible power supply is specified.

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