JP6649239B2 - Uninterruptible power supply system - Google Patents

Description

  The present invention relates to an uninterruptible power supply system, and more particularly to control of the number of operating units in an uninterruptible power supply system including a plurality of uninterruptible power supplies connected in parallel.

  The uninterruptible power supply may be used to supply power to a load by connecting a plurality of loads to one load in addition to a case where one load is connected to one load.

  In general, the efficiency of the uninterruptible power supply is maximized when the load factor is in a certain range (for example, about 70 to 80%), and the efficiency is reduced when the load factor is lower than or higher than the range. Tends to decrease. Therefore, in an uninterruptible power supply system using a plurality of uninterruptible power supplies each connected in parallel to be able to operate independently, at a low load, some uninterruptible power supplies among the plurality of uninterruptible power supplies are The operation efficiency of the entire system is improved by raising the load factor of each uninterruptible power supply during operation to the above-mentioned range by stopping the operation.

  According to this, by monitoring the load factor of each uninterruptible power supply during operation, and by appropriately selecting the number of operating units according to the change in the load factor, it is possible to maintain the maximum operating efficiency of the entire uninterruptible power supply system It becomes possible. For example, Japanese Unexamined Patent Application Publication No. 2010-166654 (Patent Literature 1) discloses that a required number of uninterruptible power supply devices are operated based on the selection result of the number of operation units, and unnecessary uninterruptible power supply devices are stopped to stand by A configuration is described in which the operation number control is automatically executed.

JP 2010-166654 A

  However, in the uninterruptible power supply system described in Patent Literature 1, the uninterruptible power supply to be operated is changed according to the change in the number of operating units only when the load factor of the operating uninterruptible power supply changes. Therefore, there is a possibility that the operation time of each uninterruptible power supply device is biased.

  In particular, when the load factor of the uninterruptible power supply hardly changes and the number of operating units does not change, since each uninterruptible power supply is maintained in the operating state or the standby state, the operation between a plurality of uninterruptible power supply units It is expected that the unequal time will be increased.

  The components that make up the uninterruptible power supply and the storage batteries included in the uninterruptible power supply degrade with operating time, and eventually reach the end of their life. Operating the uninterruptible power supply system with some of the plurality of uninterruptible power supplies degraded may reduce the stability and reliability of the uninterruptible power supply system.

  SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and an object of the present invention is to positively switch between an operation state and a standby state of each uninterruptible power supply, thereby providing a plurality of uninterruptible power supplies. An object of the present invention is to provide an uninterruptible power supply system for equalizing operation time between power supply devices.

  According to one aspect of the present invention, an uninterruptible power supply system includes a plurality of uninterruptible power supply devices and a control device. The plurality of uninterruptible power supplies are connected in parallel to the load. The control device operates the number of uninterruptible power supplies required to supply power to the load among the plurality of uninterruptible power supplies, and stops the remaining uninterruptible power supplies to enter a standby state. Be composed. Further, the control device is configured to start at least a part of the uninterruptible power supply in the standby state at predetermined time intervals.

  Also preferably, the control device activates at least a part of the uninterruptible power supply in the standby state, and then stops at least a part of the uninterruptible power supply in the operating state. It is composed of

  Also preferably, the control device is configured to accumulate the operation time of each of the plurality of uninterruptible power supply devices. Further, the control device is configured to stop the uninterruptible power supply having a long cumulative operating time among the uninterruptible power supplies in the operating state.

  Also preferably, the control device is configured to accumulate the operation time of each of the plurality of uninterruptible power supply devices. Then, the control device is configured to start the uninterruptible power supply having a short cumulative operation time among the uninterruptible power supply in the standby state.

  Also preferably, the control device is configured to measure a standby time during which the plurality of uninterruptible power supply devices have been in a standby state after being stopped. Then, the control device is configured to activate the uninterruptible power supply having the long standby time among the uninterruptible power supply in the standby state.

  According to the present invention, it is possible to provide an uninterruptible power supply system that equalizes the operation time by positively switching the operation state and the standby state of each uninterruptible power supply.

FIG. 1 is a diagram showing a basic configuration of an uninterruptible power supply system according to a first embodiment of the present invention. FIG. 2 is a diagram illustrating a configuration example of the uninterruptible power supply device illustrated in FIG. 1. 5 is a timing chart illustrating an example of an operation of the uninterruptible power supply system according to the first embodiment. 4 is a flowchart illustrating an operation of the uninterruptible power supply system according to the first embodiment. 5 is a flowchart illustrating an operation of the uninterruptible power supply system according to the first modification of the first embodiment. 6 is a timing chart illustrating an example of an operation of the uninterruptible power supply system according to the first modification of the first embodiment. 5 is a flowchart illustrating an operation of an uninterruptible power supply system according to a second modification of the first embodiment. 9 is a flowchart illustrating an operation of the uninterruptible power supply system according to the second embodiment. 5 is a timing chart for comparing respective examples of the operation of the uninterruptible power supply system according to the first and second embodiments.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following, the same and corresponding portions in the drawings are denoted by the same reference characters, and description thereof will not be repeated in principle.

[Embodiment 1]
Hereinafter, a first embodiment according to the present invention will be described with reference to the drawings. FIG. 1 is a diagram illustrating a basic configuration of the uninterruptible power supply system according to the first embodiment of the present invention. The uninterruptible power supply system 1 according to the embodiment shown in FIG. 1 includes a plurality of uninterruptible power supplies (UPS) connected to a network 2 mainly including LAN wiring. 3) and the number-of-operated-operations control device 4 as load factor monitoring control means are connected via a network interface 5 respectively.

  The plurality of UPSs 3 are housed in a housing 6 together with the corresponding network interface 5, and are connected in parallel to a load 7.

  On the other hand, the operating number control device 4 is housed in the housing 8 together with the corresponding network interface 5.

[Basic configuration of UPS]
FIG. 2 is a diagram showing a configuration example of the UPS 3 shown in FIG. Referring to FIG. 2, UPS 3 is connected to control unit 9, converter 12 connected to AC power supply 10 via connection terminal 11, smoothing capacitor 13, and load 7 via load connection terminal 20. An inverter 14, a chopper circuit 17 connected to a storage battery 15 via a battery connection terminal 16, a voltage sensor 18, and a current sensor 19 are provided.

  The control unit 9 controls a current value output from the inverter 14 to the load 7 via the load connection terminal 20. Converter 12 converts AC power into DC power in a normal state where AC power is supplied from AC power supply 10, and supplies the DC power to inverter 14 and chopper circuit 17.

Smoothing capacitor 13 smoothes the DC voltage output from converter 12.
Voltage sensor 18 detects an AC voltage input from AC power supply 10 to converter 12 via connection terminal 11, and transmits a detection signal to control unit 9.

  The control unit 9 can determine whether or not the AC power supply 10 is in a power outage state based on the voltage detection signal of the voltage sensor 18. When the AC power supply 10 is in a power failure state, the control unit 9 switches the input to the inverter 14 from the converter 12 on the AC power supply 10 side to the chopper circuit 17 on the storage battery 15 side.

  The chopper circuit 17 is connected to the storage battery 15 via the battery connection terminal 16 and to the DC side of the inverter 14. Chopper circuit 17 mutually converts the voltage of storage battery 15 and the DC voltage between converter 12 and inverter 14. In a normal state, chopper circuit 17 charges storage battery 15 with the DC power generated by converter 12.

  On the other hand, when the AC power supply 10 fails, the chopper circuit 17 supplies the DC power from the storage battery 15 to the inverter 14.

  In a normal state, inverter 14 converts DC power from converter 12 into AC power and supplies the AC power to load 7. In a power failure state, inverter 14 converts DC power from storage battery 15 into AC power and supplies the AC power to load 7.

  Current sensor 19 detects a current value output from inverter 14. This current value is converted by the current sensor 19 into a current detection signal. The current detection signal is used for feedback control in the independent control in the control unit 9.

  The control unit 9 is connected to the network 2 via the network interface 5 shown in FIG. The control unit 9 transmits information indicating various states of its own UPS 3 to the operating number control device 4 using the network 2. The various information includes a current detection signal, a voltage detection signal, information indicating a result of determination of a power failure state of the AC power supply 10, information indicating whether the UPS 3 is in a standby state or an operation state, and the like.

  Further, the control unit 9 transmits the load factor of its own UPS 3 to the operating number control device 4 using the network 2. Here, the “load factor” of the UPS 3 indicates the ratio (unit%) of the current actually output from the UPS 3 when the rated current of the UPS 3 is 100%.

  The control unit 9 controls the operation of its own UPS3. Thereby, each UPS 3 can operate independently from other UPSs 3 (independent operation). In addition to the control of the self-sustaining operation, the control unit 9 operates the own UPS 3 (operating state / standby state) based on a start instruction and a stop instruction transmitted from the operating number control device 4 via the network 2. ).

  Further, as described later, when a failure occurs in each UPS 3, a signal including information on the failure is output from the failed UPS 3 to the operating number control device 4 via the network 2.

[Control of each UPS by operation number control device]
Next, the load factor monitoring function of the operating number control device 4 will be described. As shown in FIG. 1, in the housing 8, an operating number control device 4 connected to the network 2 via the network interface 5 is provided. The operating number control device 4 receives various information of the UPS 3 (including an operation / standby state and a load factor) from each of the plurality of UPSs 3 via the network 2.

  The operating number control device 4 determines the operating number (hereinafter, also referred to as an optimum operating number) of the UPS 3 that maximizes the operating efficiency of the entire uninterruptible power supply system 1 based on these pieces of information.

  Specifically, the operating number control device 4 determines the optimal number of operating units such that the load factor of the running uninterruptible power supply falls within a predetermined range (for example, about 70 to 80%) at which the efficiency is maximum. . For example, when the load factor drops to less than 70%, the operating number control device 4 calculates the load factor when the operating number is reduced by one. If the calculated load factor falls within the range of 70% to 80%, the number-of-operated-operations control device 4 determines a value obtained by subtracting one from the current number of operated units as the optimum number of operated units. On the other hand, if the calculated load factor exceeds 80%, the operating number control device 4 determines the current operating number as the optimum operating number.

  Then, the operating number control device 4 determines which of the UPS 3 is set to the operation / standby state based on the determined optimum operating number. The operating number control device 4 transmits a start instruction or a stop instruction to each UPS 3 via the network 2 based on these determinations.

  As the load factor is monitored by the operating number control device 4 in this way, the plurality of UPSs 3 that are independently controlled independently are adjusted to the optimum operating number according to the change in the load ratio. As a result, an energy-saving operation for stopping unnecessary UPS 3 (so-called eco-drive) is performed.

  Next, control by the operating number control device 4 when a failure occurs in any of the UPSs 3 will be described. The operating number control device 4 is configured to determine whether any of the plurality of UPSs 3 connected to the network 2 has a failure based on information from the control unit 9 of each UPS 3. I have. The operating number control device 4 continues the operating number control when no UPS 3 has failed.

  On the other hand, when a failure occurs in any one of the UPSs 3, the operating number control device 4 stops the operating number control after giving start commands to all the standby UPSs 3. Here, the term “failure” includes all serious failures and minor failures such that operation can be continued without repair for a while. Specifically, for example, a failure of each power conversion device of the UPS 3, a cooling fan, a temperature rise exceeding a normal assumption, and the like are included. That is, the UPS 3 includes a state in which overheating, noise, and vibration are generated, and the UPS 3 stops operating or does not reach the shutdown but cannot operate normally.

  In such an uninterruptible power supply system, a UPS to be newly started or stopped is selected when the optimum number of operating units increases or decreases according to the change in the load factor. In Patent Literature 1, the operation time of each UPS is equalized by selecting the UPS to be started or stopped based on the accumulated data of the operation time of each UPS. However, in such a configuration, since the UPS to be operated is changed only when the load factor changes, the operation is performed in a situation where the load factor hardly changes and the optimum number of operating vehicles is constant. The opportunity to change the power UPS may be limited. In this case, equalization may not be sufficient.

  Therefore, in order to solve these problems, in the uninterruptible power supply system 1 according to the first embodiment, the operating number control device 4 activates at least a part of the standby UPS at predetermined time intervals. Be composed.

  Here, when at least a part of the UPSs in the standby state is started, the number of operating UPSs becomes larger than the optimal number of operating UPSs, so that the load factor of each UPS falls below a predetermined range. Therefore, the operating number control device 4 performs the above-described operating number control, and stops at least a part of the UPS in the operating state to make the operating number coincide with the optimum operating number.

  In this way, by activating at least a part of the UPS in the standby state at a predetermined time interval during the execution of the control of the number of operating units, at least a part of the UPS in the operation state is stopped, and the UPS to be operated is substantially stopped. Can be changed. According to this, it is possible to prevent an increase in operating time unevenness among a plurality of UPSs in a situation where the optimum number of operating vehicles is constant. In the following description, changing the UPS to be operated is also referred to as “rotation”.

  More specifically, the operating number control device 4 activates at least a part of the UPS in the standby state at predetermined time intervals to increase the number of operating units, waits for the elapse of the predetermined time, and starts the operation of the UPS in the operating state. Stop at least part. Until the predetermined time elapses, both the newly started UPS and the newly stopped UPS operate, so that it is possible to prevent a temporary power shortage during rotation. In consideration of the case where the optimum number of operating vehicles increases immediately after the UPS is started for rotation, taking a time allowance between the start of the UPS and the stop of the UPS, the stable power supply is achieved. It is possible.

  In the following description, a predetermined time interval at which rotation is performed is also referred to as “rotation time T2”. The rotation time T2 specifically indicates a time interval for starting at least a part of the UPS in a standby state for the purpose of rotation. The rotation time T2 is set, for example, to about one month.

  In the rotation, a predetermined time from starting at least a part of the standby UPS to stopping at least a part of the operating UPS is also referred to as “overlap time T1”. The overlap time T1 is set, for example, to about one hour.

  Next, an example of operation of controlling the number of operating vehicles by the uninterruptible power supply system 1 according to the first embodiment will be described with reference to FIG. FIG. 3 shows transition of the operation state / standby state of the plurality of UPSs 3 according to the passage of time. Note that the hatched portion in FIG. 3 indicates the time during which the UPS is in the operating state, and the white portion in FIG. 3 indicates the time during which the UPS is in the standby state.

  FIG. 3 illustrates an example in which the uninterruptible power supply system 1 includes five UPSs 3 (UPSs 31 to 35). In the example of FIG. 3, it is assumed that the load factor of each UPS in the operating state is constant from time t0 to t7, and the load factor increases at time t7. Further, it is assumed that the load factor decreases at time t12 after time t7.

  When starting or stopping any of the UPSs for changing or rotating the number of operated vehicles due to a change in the load factor, consider a case where the UPS 3 to be started or stopped is determined based on the accumulated operation time.

  Here, the “cumulative operation time of the UPS” corresponds to the total operation time of the UPS. The total operation time is obtained by accumulating the operation time from the new state of the UPS. When the UPS is started, the one with a short cumulative operation time is selected, and when the UPS is stopped, the one with a long cumulative operation time is selected.

  In the first embodiment, it is assumed that the operating number control device 4 activates one of the five UPSs 3 every time the rotation time T2 elapses. Then, it is assumed that, after activating one UPS 3, the operating number control device 4 waits for the overlap time T <b> 1 and stops one UPS 3. At this time, the operating number control device 4 does not select the UPS 3 started immediately before as the UPS to be stopped.

  Further, when starting or stopping any one of the UPSs 3 for changing or rotating the load factor, the operating number control device 4 determines the UPS to be started or stopped based on the accumulated operation time of each UPS 3. Shall be. Specifically, when starting the UPS, the operating number control device 4 selects the UPS 3 in the standby state that has the shortest cumulative operating time. Further, when stopping the UPS, the operating number control device 4 selects the one with the longest cumulative operating time.

  If there are two or more UPS3s having the same cumulative operation time, the operating number control device 4 preferentially starts or stops the UPS3 with the smaller device number.

  In FIG. 3, when the uninterruptible power supply system 1 is started (time t0), the accumulated operation time of each of the UPSs 31 to 35 is set to 0. Further, it is assumed that the optimum number of operating units derived from the load at the time of starting the uninterruptible power supply system 1 is three.

  As described above, T2 indicates the rotation time, and T1 indicates the overlap time. The elapsed time from the time when the standby UPS 3 was activated for the previous rotation is denoted by te.

  The above conditions are the same in the timing charts of FIGS. 6 and 9 unless otherwise specified.

  At time t0, when the control of the number of operating units of the uninterruptible power supply system 1 is started, as described above, the optimum number of operating units is three, and the cumulative operation times of the UPSs 31 to 35 at this time are all zero. Then, three UPSs 3 (UPS 31 to UPS 33) having the smaller device numbers are activated. The operating number control device 4 measures the elapsed time te starting from the time t0.

  At time t1, when the elapsed time te reaches the rotation time T2, the operating number control device 4 rotates the UPS 3 to be operated. That is, the operating number control device 4 activates the UPS 3 in the standby state having the shortest cumulative operating time. However, since the cumulative operation times of the UPS 34 and the UPS 35 are equal to 0 here, the UPS 34 with the smaller device number is activated.

  At time t2 when the overlap time T1 has elapsed from time t1, the operating number control device 4 selects the UPS to be stopped. Here, since the load factor is constant, the optimum number of operating vehicles is three. The operating number control device 4 issues a stop command to the UPS 3 in the operating state that has the longest operating time among the UPS 3 in the operating state. However, since the accumulated operation times of the UPSs 31 to 33 are equal, the UPS 31 with the smallest device number is stopped, and the number of UPS 3s operated returns to three again.

  At time t3 when the rotation time T2 has elapsed from time t1, the operating number control device 4 rotates the UPS 3 to be operated. Here, the UPS 35 having the shortest cumulative operation time is started.

  At time t4 when the overlap time T1 has elapsed from time t3, the operating number control device 4 selects the UPS to be stopped. Here, since the load factor is constant, the optimum number of operating vehicles is three. The operating number control device 4 issues a stop command to the UPS with the longest cumulative operating time. However, since the cumulative operation times of the UPSs 32 and 33 are equal, the UPS 32 with the smaller device number is stopped, and the number of operating UPSs returns to three again.

  At time t5 when the rotation time T2 has elapsed from time t4, the operating number control device 4 rotates the UPS 3 to be operated. At time t5, the UPS 31 that has the shortest cumulative operation time among the standby UPSs 3 is the UPS 31, so the UPS 31 is started.

  At time t6 when the overlap time T1 has elapsed from time t5, the operating number control device 4 selects the UPS 3 to be stopped. The operating number control device 4 issues a stop command to the UPS with the longest cumulative operation time, that is, the UPS 33. As a result, the number of operating UPSs returns to three again.

  Next, at time t7, it is assumed that the load factor increases and the optimum number of operating vehicles increases from three to four. At this time, the operating number control device 4 activates the UPS 32 having the shorter cumulative operation time among the UPSs 32 and 33 which are the standby UPSs.

  At time t8 when the rotation time T2 has elapsed from time t6, the operating number control device 4 rotates the UPS 3 to be operated. In this case, since the UPS in the standby state is only the UPS 33, the UPS 33 is activated.

  At time t9 when the overlap time T1 has elapsed from time t8, the operating number control device 4 selects the UPS 3 to be stopped. Here, the optimal number of operating vehicles is four. Among the UPSs in operation, the UPSs with the longest cumulative operation time are the UPSs 33 and 34, but since the UPS 33 has just been started at the immediately preceding time t8, the UPS 34 is stopped.

  At time t10 when the rotation time T2 has elapsed from time t8, the operating number control device 4 rotates the UPS 3 to be operated. Here, since the only UPS in the standby state is the UPS 34, the UPS 34 is activated.

  At time t11 when the overlap time T1 has elapsed from time t10, the operating number control device 4 selects the UPS 3 to be stopped. Here, the optimal number of operating vehicles is four. Therefore, the operating number control device 4 stops the UPS 33 having the longest cumulative operating time among the operating UPSs.

  Next, at time t12, it is assumed that the load factor decreases and the optimal number of operating vehicles decreases from four to three. At this time, the operating number control device 4 stops the UPS 32 having the longest cumulative operating time among the operating UPSs 31, 32, 34, and 35.

  At time t13 when the rotation time T2 has elapsed from time t11, the operating number control device 4 rotates the UPS 3 to be operated. Here, of the standby UPSs 32 and 33, the UPS 32 with the shorter cumulative operation time is activated.

  At time t14 when the overlap time T1 has elapsed from time t13, the operating number control device 4 selects the UPS 3 to be stopped. Here, the optimal number of operating units is three. Therefore, the operating number control device 4 stops the UPS 34 having the longest cumulative operating time among the operating UPSs.

  FIG. 4 is a flowchart illustrating control of the number of operating units performed by the uninterruptible power supply system according to the first embodiment of the present invention. The process shown in the flowchart of FIG. 4 is repeatedly executed by the operating number control device 4 at a predetermined cycle after the uninterruptible power supply system 1 is started.

  Specifically, when the operating number control device 4 starts the operating number control, in step S1, based on a signal sent from each UPS 3, it is determined whether or not any of the plurality of UPSs 3 has a failure. Is determined.

  If it is determined that a failure has occurred in any of the UPSs 3 (YES in step S1), the operating number control device 4 transmits a start command to all the UPSs 3 in the standby state in step S11. On the other hand, if it is determined in step S1 that no failure has occurred in any of the UPSs 3 (NO in step S1), the operating number control device 4 proceeds to step S2.

  In step S2, the operating number control device 4 integrates the cumulative operating time of each UPS 3 for the UPS 3 in the operating state. The operating number control device 4 also integrates the elapsed time te since the UPS 3 in the standby state was started for the previous rotation.

  In step S3, the operating number control device 4 determines the optimum operating number Nr based on the load factor of the UPS 3 during the parallel operation. In step S4, the operating number control device 4 determines whether or not the determined optimum operating number Nr is larger than the current operating number Nc. If the optimum number of operating vehicles Nr is larger than the current number of operating vehicles Nc (YES in step S4), the operating vehicle number control device 4 proceeds to step S5.

  In step S <b> 5, the operating number control device 4 outputs a start command via the network 2 to the UPS 3 in the standby state having the smallest cumulative operating time. By starting the UPS 3 that has received the start command, the number of operating UPSs 3 increases.

  On the other hand, if the optimum number of operating vehicles Nr is smaller than the current number of operating vehicles Nc (YES in step S6), the operating vehicle number controller 4 determines in step S7 whether the elapsed time te exceeds the overlap time T1. judge. If the elapsed time te exceeds the overlap time T1 (YES in step S7), the operating number control device 4 proceeds to step S8.

  In step S <b> 8, the operating number control device 4 outputs a stop command via the network 2 to the UPS 3 in the operating state with the largest cumulative operating time. By stopping the UPS 3 that has received the stop command, the number of operating UPSs 3 decreases.

  On the other hand, when the optimum number of operating vehicles Nr matches the current number of operating vehicles Nc (NO in step S6), the operating vehicle number control device 4 proceeds to step S9.

  In step S9, the operating number control device 4 compares the elapsed time te integrated in step S2 with the rotation time T2. If it is determined that the elapsed time te has exceeded the rotation time T2 (YES in step S9), the operating number control device 4 proceeds to step S10, in which the cumulative operation time of the UPS 3 in the standby state is the smallest. A start command is output via the network 2. By starting the UPS 3 that has received the start command, the number of operating UPSs 3 increases. Further, the operating number control device 4 clears the elapsed time te (te = 0).

  On the other hand, when it is determined that the elapsed time te does not exceed the rotation time T2 (NO in step S9), the operating number control device 4 does not change the currently operated UPS3.

  As described above, in the uninterruptible power supply system 1 according to the first embodiment, the plurality of UPSs 3 connected to the load 7 in parallel with each other operate based on the load factor of each UPS 3 so that the number of UPS 3 becomes the optimum number of operation. It is controlled by the number control device 4. Furthermore, in parallel with the control of the number of operating units, the UPS 3 in the standby state is started at a predetermined time interval (rotation time T2), thereby performing the rotation for changing the UPS 3 to be operated.

  The mechanism by which the rotation of the UPS 3 to be driven is realized will be described in more detail with reference to the flowchart of FIG.

  In FIG. 4, attention is paid to a case where the current operating number Nc matches the optimum operating number Nr and the elapsed time te exceeds the rotation time T2 (YES in step S9).

  At this time, the operating number of UPS 3 is the optimum operating number Nr calculated from the load factor. Therefore, when one UPS 3 is started in step S10, the number of operating UPSs 3 is one more than the optimal number of operating Nr.

  Thereafter, if the optimum operating number Nr does not change, it is determined that the optimum operating number Nr is one less than the current operating number Nc (YES in step S6). In this case, if the elapsed time te is longer than the overlap time T1 (YES in step S7), the operating number control device 4 stops one UPS 3 in step S8. As a result, the current operating number can be made to match the optimum operating number.

  In step S8, the operating number control device 4 may be configured not to stop the UPS 3 started in step S10 immediately before. That is, in step S8, among the UPSs 3 in the operating state, the UPS 3 with the largest cumulative operating time may be stopped from the UPSs 3 excluding the UPS 3 activated immediately before. By doing so, the frequency of starting and stopping of each UPS 3 can be suppressed, so that there is an advantage that the possibility of failure at the time of starting or stopping is reduced. This is the same in the first and second modifications of the first embodiment and the flowchart (FIGS. 5, 7, and 8) of the second embodiment, and therefore, the description will not be repeated. Note that such a configuration is employed in the timing charts (FIGS. 3, 6, and 9) of the first embodiment, the first modification of the first embodiment, and the second embodiment.

  The number of UPSs that are started / stopped for this rotation is not limited to one, but may be a plurality. The UPS that is started / stopped for this rotation is not limited to a part of the standby / started UPS, and may be all.

  Further, as described above, when any one of the plurality of UPSs 3 has a failure, the operating number control device 4 stops controlling the operating number of the UPSs 3 after the start command is given to all the standby UPSs 3. Is done.

  For this reason, all the UPSs 3 are activated once, and each of the UPSs 3 performs a normal independent operation. Therefore, even if an unexpected situation occurs in the system, stable operation can be performed.

  As described above, according to the uninterruptible power supply system according to Embodiment 1, the uninterruptible power supply to be operated can be changed at predetermined time intervals. Therefore, it is possible to eliminate the possibility that the operation time of each uninterruptible power supply device is biased. That is, it is possible to provide an uninterruptible power supply system that actively switches the operation state of each uninterruptible power supply and equalizes the operation time.

[Modification 1]
In the uninterruptible power supply system 1 according to the first modification of the first embodiment, when the optimum number of operating vehicles changes due to a change in the load factor, the operating vehicle number control device 4 starts the standby UPS, or When the UPS in the state is stopped, the elapsed time te is cleared, and the start of the next rotation is delayed. That is, if there is a change in the number of operating units due to a change in the load factor during the rotation period, the next rotation is delayed. Thus, the possibility of failure due to surge current can be reduced by reducing the number of times the UPS 3 is started and stopped.

  FIG. 5 is a flowchart illustrating control of the number of operating units, which is executed in the uninterruptible power supply system according to the first modification of the first embodiment of the present invention. The process shown in the flowchart of FIG. 5 is executed by the operating number control device 4 at a predetermined cycle.

  The uninterruptible power supply system 1 according to the first modification of the first embodiment has the same overall configuration as the uninterruptible power supply system 1 according to the first embodiment, and a part of the process of controlling the number of operating units is different. In the flowchart of FIG. 5, steps S5B and S8B different from FIG. 4 are mainly described among the processes shown in the flowchart of FIG.

  Referring to FIG. 5, in step S5B, the number-of-operated-operations control device 4 outputs a startup command to the UPS having the shortest cumulative operation time via the network 2 and clears the elapsed time te. In step S8B, a stop command is output to the UPS having the longest cumulative operation time via the network 2, and the elapsed time te is cleared.

  Next, an operation example of controlling the number of operating vehicles by the uninterruptible power supply system 1 according to the first modification of the first embodiment will be described with reference to FIG. In the timing chart of FIG. 6, among the operations shown in the timing chart described in FIG. 3, t27, 28, 32, and 33 different from those in FIG. 3 will be mainly described.

  6 and FIG. 3, the operations at times t20 to 26, 29 to 31, and 34 to 35 in FIG. 6 are the same as the operations at times t0 to 6, 9 to 11, and 14 to 15 in FIG. .

  In FIG. 6, at time t27, when the load factor increases and the optimum number of operating vehicles increases from three to four, the UPS 32 with the shorter cumulative operating time is activated among the standby UPSs 32 and 33. At the same time, the elapsed time te is cleared.

  As the elapsed time te is cleared when the number of operating vehicles increases, the next rotation is performed at time t28 when the rotation time T2 has elapsed from time t27. This time t28 is later than the time t8 in FIG.

  At time t32, when the load factor decreases and the optimal number of operating vehicles decreases from four to three, the UPS 32 with the longest cumulative operating time among the operating UPSs 31, 32, 34, and 35 is stopped. At the same time, the elapsed time te is cleared.

  As the elapsed time te is cleared when the number of operating vehicles decreases, the next rotation is performed at time t33 when the rotation time T2 has elapsed from time t32. This time t33 is later than the time t13 in FIG.

  As described above, in the uninterruptible power supply system of the first modification, the operating number control device 4 clears the elapsed time te when the operating number changes. In the present embodiment, when changing the number of operating vehicles, the UPS to be started or stopped is selected based on the cumulative operation time of each UPS. It contributes to time equalization. That is, the control of the number of units by the load change substantially corresponds to the rotation. Therefore, it is reasonable to reduce the frequency of rotations with similar effects. In addition, by reducing the number of times the UPS 3 is started and stopped, surge current and the like accompanying the start and stop can be suppressed, and deterioration of the UPS 3 can be suppressed.

  The other configuration and operation and effect are the same as those of the first embodiment, and thus description thereof will not be repeated.

[Modification 2]
In the uninterruptible power supply system 1 according to the second modification of the first embodiment, when the optimum number of operating vehicles changes or when rotation is performed, the operating vehicle number control device 4 waits regardless of the cumulative operation time of each UPS 3. One of the UPSs in the operating state is started, or one of the UPSs in the operating state is stopped. As a result, rotation can be realized even with a simpler UPS 3.

  FIG. 7 is a flowchart illustrating control of the number of operating units performed by the uninterruptible power supply system 1 according to the second modification of the first embodiment of the present invention. The process shown in the flowchart of FIG. 7 is executed by the operating number control device 4 at a predetermined cycle.

  The uninterruptible power supply system 1 according to the second modification of the first embodiment has the same overall configuration as the uninterruptible power supply system 1 according to the first embodiment, and a part of the unit control process is different. In the flowchart of FIG. 7, steps S5C, S8C, and S10C that are different from those of FIG. 4 among the operations shown in the flowchart of FIG. 4 will be mainly described.

  Referring to FIG. 7, the operating number control device 4 outputs a start command via the network 2 to one of the standby UPSs 3 in step S5C. Also, in step S8C, the operating number control device 4 outputs a stop command via the network 2 to any of the UPSs 3 in the operating state. Similarly, in step S10C, the operating number control device 4 outputs a start command via the network 2 to one of the standby UPSs 3 and clears te.

  In steps S5C and S8C, for example, a start command may be output to a UPS3 randomly selected from the standby UPS3. In step S10C, for example, a stop command may be output to the UPS 3 that is randomly selected from the running UPSs 3.

  That is, unlike the first embodiment, the operating number control device 4 of the second modification of the first embodiment selects the UPS to be started or stopped irrespective of the accumulated operation time of each UPS 3. This eliminates the need to calculate, store, and output the accumulated operation time, so that the rotation function can be performed even with a simpler configuration of the UPS 3.

  The other configuration and operation and effect are the same as those in the first embodiment, and thus description thereof will not be repeated.

[Embodiment 2]
The uninterruptible power supply system 1 according to the first embodiment is configured to activate the UPS 3 having the shortest cumulative operation time among the UPSs 3 in the standby state. When there is a UPS 3 having a long operation time, the UPS 3 may be kept in a standby state for a long time without being activated. In this case, even if a failure occurs in the UPS 3, the failure cannot be detected. That is, it is difficult to evaluate the soundness of the uninterruptible power supply system 1.

  In the uninterruptible power supply system 1 according to the second embodiment, when the optimum number of UPS 3 operated increases due to an increase in the load factor, or when the rotation is performed, of the UPS 3 in the standby state, the time during which the standby state is maintained. The UPS 3 with the longest (standby time) is started. As a result, an opportunity to drive the UPS 3 in which the standby state continues due to the long cumulative operation time can be created. Thereby, the soundness of the uninterruptible power supply system 1 can be evaluated.

  FIG. 8 is a flowchart illustrating control of the number of operating units, which is executed by the uninterruptible power supply system 1 according to Embodiment 2 of the present invention. The process shown in the flowchart of FIG. 8 is executed by the operating number control device 4 at a predetermined cycle.

  The uninterruptible power supply system 1 according to the second embodiment has the same overall configuration as the uninterruptible power supply system 1 according to the first embodiment, and partially differs in the control of the number of operating units. In the flowchart of FIG. 8, steps S5D and S10D that are different from those of FIG. 4 are mainly described among the operations illustrated in the flowchart of FIG.

  In the flowchart of FIG. 8, in step S5D, the operating number control device 4 outputs a start command via the network 2 to the UPS 3 having the longest standby time among the UPSs 3 in the standby state. Also, in step S10D, the operating number control device 4 outputs a start command to the UPS 3 having the longest standby time via the network 2 and clears the elapsed time te.

  Next, an operation example of controlling the number of operating vehicles by the uninterruptible power supply system 1 according to the second embodiment will be described using FIG.

  In the example of FIG. 9, the cumulative operation time of each UPS 3 when the uninterruptible power supply system 1 is started (time t40) is 0 for the UPSs 31 to 34, and it is assumed that only the UPS 35 is extremely long. For example, all of the UPSs 31 to 34 are new products, while the UPS 35 is a used product.

  First, as a comparative example, an operation of controlling the number of operating units by the uninterruptible power supply system 1 according to the first embodiment will be described.

  At time t40, when the control of the number of operating units of the uninterruptible power supply system 1 is started, the cumulative operation times of the UPSs 31 to 34 at this time are all 0, so the three UPSs 3 (UPS 31 to UPS 33) with the smaller device numbers are used. Is started.

  At time t41, since the elapsed time te from time t40 has reached the rotation time T2, the operating number control device 4 rotates the UPS 3 to be operated. That is, among the stopped UPSs, the one with the shortest cumulative operation time, that is, the UPS 34 is started.

  At time t42 when the overlap time T1 has elapsed from time t41, the operating number control device 4 selects the UPS to be stopped. Here, since the load factor is constant, the optimum number of operating vehicles is three. The operating number control device 4 issues a stop command to the UPS 3 having the longest accumulated operating time among the UPSs 3 in the operating state. However, since the cumulative operation times of the UPSs 31 to 33 are equal, the UPS 31 with the smallest device number is stopped, and the number of UPS 3s operated returns to three again.

  At time t43 when the rotation time T2 has elapsed from time t41, the operating number control device 4 rotates the UPS 3 to be operated. Here, among the UPSs 3 in the standby state, the UPS 31 with the shortest cumulative operation time is started.

  Similarly, after time t44, only the UPSs 31 to 34 whose cumulative operation time is shorter than that of the UPS 35 are sequentially activated. Therefore, the cumulative operation time of the UPSs 31 to 34 is equalized and approaches the cumulative operation time of the UPS 35, so that the cumulative operation time of the entire uninterruptible power supply system 1 is equalized. However, on the other hand, the UPS 35 is not activated at all until the cumulative operation time of the UPSs 31 to 34 becomes substantially equal to the cumulative operation time of the UPS 35. Therefore, even if a failure occurs in the UPS 35, the failure may not be detected.

  In order to solve such a problem, in the second embodiment, when starting any one of the UPSs 3 as shown in the flowchart of FIG. Adopt a configuration to start.

  FIG. 9 (B) is an operation example of the number-of-operated-units control by the uninterruptible power supply system 1 according to Embodiment 2 of the present application, and the cumulative operation time at the time of starting each UPS 3 is the same as in FIG. 9 (A).

  At time t40, when the operation number control is started, the standby times of the UPSs 31 to 35 at this time are all 0, so the three UPSs 3 (UPS 31 to UPS 33) with the smaller device numbers are activated.

  At time t41 when the rotation time T2 has elapsed from time t40, the operating number control device 4 activates the UPS 34 having the smaller device number among the UPSs 34 and 35 having the longer standby time.

  At time t42 when the overlap time T1 has elapsed from time t41, the operating number control device 4 stops the UPS 31 with the smallest number among the UPSs 31 to 33 in the operating state.

  At time t43 when the rotation time T2 has elapsed from time t41, the operating number control device 4 activates the UPS 35 having the longer standby time among the UPSs 31 and 35 in the standby state.

  At time t44 when the overlap time T1 has elapsed from time t43, the number-of-operated-operations control device 4 selects one of the UPSs 32 and 33 having the longest accumulated operation time among the UPSs 3 in the operation state (excluding the UPS 35 started immediately before). , The UPS 32 having the smaller device number is stopped.

  At time t45 when the rotation time T2 has elapsed from time t43, the operating number control device 4 activates the UPS 31 having the longer standby time among the UPSs 31 and 32 in the standby state.

  At time t44 when the overlap time T1 has elapsed from time t43, the operating number control device 4 stops the UPS 35 having the longest accumulated operating time among the UPSs 3 in the operating state.

  Similarly, after time t44, the operating number control device 4 mainly operates the UPSs 31 to 34 with the short cumulative operation time, but the UPS 35 with the long cumulative operation time also has a longer standby time than the other UPSs. Drive temporarily. Therefore, similarly to the first embodiment, since the cumulative operation times of the UPSs 31 to 34 are equalized and the cumulative operation time approaches the cumulative operation time of the UPS 35, the cumulative operation time of the entire uninterruptible power supply system 1 is reduced. Can be equalized. Further, even if a failure occurs in the UPS 35 having an extremely long accumulated operation time, the failure can be detected when the UPS 35 is operated. Therefore, the soundness of the uninterruptible power supply system 1 can be ensured.

  In other words, in addition to the operation and effect of the first embodiment, the operating number control device 4 of the second embodiment can temporarily operate the UPS 3 having a longer standby time due to a longer cumulative operation time. it can. Thus, it is possible to confirm that the UPS 3 operates normally even if the accumulated operation time is significantly longer than the other UPSs 3. As a result, the soundness of the uninterruptible power supply system 1 can be ensured.

  The other configuration and operation and effect are the same as those in the first embodiment, and thus description thereof will not be repeated.

  The embodiments disclosed this time are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  DESCRIPTION OF SYMBOLS 1 Uninterruptible power supply system, 2 networks, 3, 31-35 UPS, 4 operation number control device, 5 network interfaces, 6 housings, 7 loads, 8 housings, 9 control units, 10 AC power supplies, 11 connection terminals, 12 Converter, 13 smoothing capacitor, 14 inverter, 15 storage battery, 16 battery terminal, 17 chopper circuit, 18 voltage sensor, 19 current sensor, 20 load connection terminal.

Claims (5)

A plurality of uninterruptible power supplies connected in parallel to the load;
While operating the number of uninterruptible power supplies required to supply power to the load among the plurality of uninterruptible power supplies, the remaining uninterruptible power supplies are stopped to be in a standby state. With a configured control device,
The control device is configured to activate at least a part of the uninterruptible power supply in the standby state at a predetermined time interval ,
The control device accumulates an elapsed time since at least a part of the uninterruptible power supply in the standby state is started, and when the integrated value of the elapsed time reaches the predetermined time interval, the standby state. While starting at least part of the uninterruptible power supply
An uninterruptible power supply system that clears the integrated value of the elapsed time when the number of units required to supply power to the load changes . The control device includes:
After activating at least a part of the uninterruptible power supply in the standby state,
The uninterruptible power supply system according to claim 1, wherein the uninterruptible power supply is configured to stop at least a part of the uninterruptible power supply in an operating state. The control device includes:
Is configured to accumulate the operation time of each of the plurality of uninterruptible power supplies,
The uninterruptible power supply system according to claim 1, wherein the control device is configured to stop the uninterruptible power supply having a long cumulative operation time among the uninterruptible power supplies in an operating state. The control device includes:
It is configured to accumulate the operation time of each of the plurality of uninterruptible power supplies,
The uninterruptible power supply system according to claim 1, wherein the control device is configured to activate the uninterruptible power supply having a short cumulative operation time among the uninterruptible power supply in the standby state. The control device is configured to measure a standby time during which each of the plurality of uninterruptible power supply devices is stopped and has been in a standby state,
The uninterruptible power supply system according to claim 1, wherein the control device is configured to activate the uninterruptible power supply having the long standby time among the uninterruptible power supplies in the standby state.

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