JP2024051794A - Uninterruptible power supply device, uninterruptible power supply device management system, computer program, and method of controlling uninterruptible power supply device - Google Patents

Abstract

To provide an uninterruptible power supply device, an uninterruptible power supply device management system, a computer program, and a method of controlling the uninterruptible power supply device capable of achieving both high-speed detection of power failures and prevention of misdetection.SOLUTION: An uninterruptible power supply device comprises: a storage unit that stores threshold information having a plurality of voltage thresholds and a plurality of sensitivities corresponding to the plurality of voltage thresholds; a detection unit that detects an input voltage; and a determination unit that determines abnormalities of the input voltage on the basis of the detected input voltage and the threshold information.SELECTED DRAWING: Figure 1

Description

The present invention relates to an uninterruptible power supply, an uninterruptible power supply management system, a computer program, and a method for controlling an uninterruptible power supply.

Patent Document 1 discloses an uninterruptible power supply device that is constantly supplied with commercial power. The uninterruptible power supply device includes an AC switch connected between an AC power supply terminal and a load, a bidirectional power converter that is connected to the commercial AC power supply terminal via the AC switch and to the load without via the AC switch, a storage battery connected to the DC terminal of the bidirectional power converter, and a power supply abnormality detection device that detects an abnormality in the voltage of the commercial AC power supply terminal and controls the AC switch to be turned off.

Japanese Patent No. 4407808

Uninterruptible power supplies that supply commercial power continuously must quickly detect power outages and switch the power supply (from AC power to emergency power). If the power outage detection speed is increased, there is a high possibility that a slight fluctuation in the input voltage (for example, a momentary voltage drop) will be detected and an unnecessary power supply switch (false detection) will be performed. On the other hand, if the detection speed is slowed down so as not to detect slight fluctuations in the input voltage, when the input voltage drops to the point where a power supply switch is necessary, the time until the power supply switch will be delayed, and there is a high possibility that fast detection will not be possible.

One aspect of the present invention provides an uninterruptible power supply, an uninterruptible power supply management system, a computer program, and a method for controlling an uninterruptible power supply that can simultaneously detect a power outage quickly and prevent erroneous detection.

An uninterruptible power supply according to one aspect of the present invention includes a storage unit that stores multiple voltage thresholds and threshold information having multiple sensitivities corresponding to the multiple voltage thresholds, a detection unit that detects an input voltage, and a determination unit that determines an abnormality in the input voltage based on the input voltage detected by the detection unit and the threshold information.

The uninterruptible power supply device of the above aspect can achieve both high-speed power outage detection and prevention of erroneous detection.

FIG. 1 illustrates an example of the configuration of an uninterruptible power supply. FIG. 11 is a diagram illustrating a first example of a relationship between an input voltage and threshold information. FIG. 11 is a diagram illustrating a first example of an abnormality determination of an input voltage based on a first voltage threshold value. FIG. 11 is a diagram illustrating a first example of an input voltage anomaly determination based on a second voltage threshold value. FIG. 13 is a diagram illustrating a second example of an input voltage anomaly determination based on a second voltage threshold value. FIG. 13 is a diagram illustrating a second example of an input voltage anomaly determination based on a first voltage threshold value. FIG. 11 is a diagram illustrating a first example of an abnormality determination of an input voltage based on a voltage threshold value in the case of a comparative example. FIG. 13 is a diagram illustrating a second example of an abnormality determination of an input voltage based on a voltage threshold value in the case of the comparative example. FIG. 11 is a diagram illustrating a second example of the relationship between the input voltage and the threshold information. FIG. 13 is a diagram showing the relationship between the input voltage and threshold information in the case of a three-phase AC power supply; FIG. 2 is a diagram illustrating an example of a control method for an uninterruptible power supply. FIG. 1 illustrates an example of a configuration of an uninterruptible power supply management system. FIG. 13 is a diagram illustrating an example of updating threshold information based on a judgment history. FIG. 11 is a diagram illustrating an example of operational information.

(1) An uninterruptible power supply according to one embodiment of the present invention includes a memory unit that stores multiple voltage thresholds and threshold information having multiple sensitivities corresponding to the multiple voltage thresholds, a detection unit that detects an input voltage, and a determination unit that determines an abnormality in the input voltage based on the input voltage detected by the detection unit and the threshold information.

(15) A computer program according to one embodiment of the present invention causes a computer to execute a process of acquiring an input voltage and determining whether the input voltage is abnormal based on the acquired input voltage and threshold information having multiple voltage thresholds and multiple sensitivities corresponding to the multiple voltage thresholds.

(16) A method for controlling an uninterruptible power supply according to one embodiment of the present invention stores multiple voltage thresholds and threshold information having multiple sensitivities corresponding to the multiple voltage thresholds, detects an input voltage, and determines whether the input voltage is abnormal based on the detected input voltage and the threshold information.

According to the uninterruptible power supply, computer program, and control method for the uninterruptible power supply of one embodiment of the present invention, threshold information having multiple voltage thresholds and multiple sensitivities corresponding to the multiple voltage thresholds is used. For example, a sensitivity corresponding to one voltage threshold is used so as not to detect an instantaneous drop in the input voltage. Also, a sensitivity corresponding to another voltage threshold is used so as to enable rapid detection of a power outage. In other words, the uninterruptible power supply of one embodiment of the present invention can achieve both rapid detection of a power outage and prevention of erroneous detection.

(2) In the uninterruptible power supply device described in (1) above, the threshold information may include a first voltage threshold and a first sensitivity corresponding to the first voltage threshold, and a second voltage threshold smaller than the first voltage threshold and a second sensitivity corresponding to the second voltage threshold and having a sensitivity equal to or greater than the first sensitivity.

According to the uninterruptible power supply device of (2) above, a first voltage threshold of high voltage and a first sensitivity of low sensitivity, and a second voltage threshold of low voltage and a second sensitivity of high sensitivity are used. When the first voltage threshold is used, the sensitivity is low (first sensitivity), so momentary voltage drops (drops) where the degree of voltage drop is relatively small are not detected, and false detection can be prevented. When the second voltage threshold is used, the sensitivity is high (second sensitivity), so power outages where the degree of voltage drop is relatively large can be quickly detected.

(3) In the uninterruptible power supply device described in (2) above, the first sensitivity and the second sensitivity may each include a first detection time and a second detection time that is equal to or shorter than the first detection time, and the determination unit may determine that the input voltage is abnormal if the input voltage detected by the detection unit is equal to or shorter than the first voltage threshold during the first detection time.

According to the uninterruptible power supply device of (3) above, the first sensitivity with low sensitivity includes a long first detection time, and the second sensitivity with high sensitivity includes a short second detection time. The detection time is the time when the input voltage becomes equal to or lower than the voltage threshold. The determination unit determines that the input voltage is abnormal when the input voltage is equal to or lower than the high voltage first voltage threshold during the long first detection time, and therefore does not detect a momentary voltage drop (drop) where the degree of voltage drop is relatively small as an input voltage abnormality. In other words, it detects a constant level of voltage drop for a certain period of time that affects the load.

(4) In the uninterruptible power supply device described in (3) above, the determination unit may determine that the input voltage is abnormal if the input voltage detected by the detection unit is equal to or lower than the second voltage threshold for the second detection time.

According to the uninterruptible power supply device of (4) above, the determination unit determines that the input voltage is abnormal when the input voltage is equal to or lower than the low-voltage second voltage threshold for the short second detection time, so that a power outage with a relatively large voltage drop can be quickly detected as an input voltage abnormality.

(5) In the uninterruptible power supply device described in any one of (2) to (4) above, the first sensitivity and the second sensitivity each include a first detection count per predetermined time and a second detection count that is equal to or less than the first detection count, and the determination unit may determine that the input voltage is abnormal when the number of times that the input voltage detected by the detection unit is equal to or less than the first voltage threshold is equal to or greater than the first detection count.

According to the uninterruptible power supply device of (5) above, the first sensitivity with low sensitivity includes the first detection count, which is a large number per predetermined time, and the second sensitivity with high sensitivity includes the second detection count, which is a small number per predetermined time. The detection count is the number of times that the input voltage becomes equal to or lower than the voltage threshold. The determination unit determines that there is an abnormality in the input voltage when the number of times that the input voltage becomes equal to or lower than the first high-voltage detection count is equal to or higher than the first high-voltage detection count, and therefore does not detect an instantaneous voltage drop (drop) where the degree of voltage drop is relatively small as an abnormality in the input voltage. This is because the number of times that the input voltage becomes equal to or lower than the first high-voltage threshold is small for an instantaneous voltage drop. In other words, a constant level of voltage drop for a certain period of time that affects the load is detected.

(6) In the uninterruptible power supply device described in (5) above, the determination unit may determine that the input voltage is abnormal if the number of times that the input voltage detected by the detection unit is equal to or less than the second voltage threshold is equal to or greater than the second detection count.

According to the uninterruptible power supply device of (6) above, the determination unit determines that the input voltage is abnormal if the number of times that the input voltage is equal to or less than the low-voltage second voltage threshold is equal to or greater than the second detection count, which is smaller, so that a power outage in which the voltage drops to a relatively large extent can be detected as an input voltage abnormality quickly. This is because, in a power outage, the input voltage falls to or less than the low-voltage second voltage threshold, and the number of detections per given time is small, so that detection can be performed quickly.

(7) The uninterruptible power supply device according to any one of (1) to (6) above may include a switching unit that switches the source of power supplied to the load when the determination unit determines that an abnormality exists in the input voltage.

According to the uninterruptible power supply device of (7) above, when a voltage drop is detected in which the input voltage is equal to or lower than the first voltage threshold, or when a power outage is detected in which the input voltage is equal to or lower than the second voltage threshold, the source of power supplied to the load is switched. This makes it possible to respond appropriately to a voltage drop of a certain level for a certain period of time that affects the load or a power outage, and to supply the required power to the load.

(8) The uninterruptible power supply device described in any one of (1) to (7) above may include a receiving unit that receives an update command for the threshold information from a remote location, and an update unit that updates the threshold information stored in the memory unit based on the update command received by the receiving unit.

According to the uninterruptible power supply device of (8) above, the threshold information can be updated based on a remote command, so the threshold information is not fixed, and it is possible to adjust the threshold information according to the status of the power system that supplies the input voltage.

(9) The uninterruptible power supply device described in any one of (1) to (8) above may include a receiving unit that receives an update command for the threshold information from a remote location, and an update history collection unit that collects an update history of the threshold information based on the update command received by the receiving unit.

According to the uninterruptible power supply device of (9) above, historical information on threshold information can be collected based on remote commands, so that, for example, threshold information that is reviewed periodically or non-periodically according to the status of the power system that supplies the input voltage can be saved as operational history.

(10) The uninterruptible power supply device according to any one of (1) to (9) above may include a judgment history collection unit that collects the judgment history of the judgment unit.

According to the uninterruptible power supply device of (10) above, the judgment history of the judgment unit is collected, so that the transition of the status of the power grid that supplies the input voltage can be saved as operational history.

(11) The uninterruptible power supply device described in (10) above may include an update unit that updates the threshold information stored in the storage unit based on the judgment history.

According to the uninterruptible power supply device of (11) above, the threshold information is updated based on the judgment history, so that, for example, in a situation where false detections are frequent, the threshold information can be adjusted to reduce false detections. Also, in a situation where a power outage occurs, the threshold information can be adjusted to enable faster detection.

(12) The uninterruptible power supply device described in (10) or (11) above may include a stop unit that stops the determination of an abnormality in the input voltage by the determination unit based on one of the multiple voltage thresholds and multiple sensitivities corresponding to the multiple voltage thresholds, based on the determination history.

According to the uninterruptible power supply device of (12) above, the input voltage abnormality determination based on one of the voltage thresholds and sensitivity is stopped. For example, if a situation occurs with a certain frequency where an input voltage abnormality is detected (determined) based on the high-sensitivity second voltage threshold but an input voltage abnormality is not detected (determined) based on the low-sensitivity first voltage threshold and there is no effect on the load (voltage drop is allowed), the input voltage abnormality determination based on the high-sensitivity second voltage threshold may be stopped. In this case, the second voltage threshold may be adjusted (updated) to a lower voltage, and the second sensitivity may be adjusted to a lower sensitivity. Also, if a situation occurs with a certain frequency where an input voltage abnormality is detected (determined) based on the low-sensitivity first voltage threshold but there is no effect on the load (voltage drop is allowed), the input voltage abnormality determination based on the low-sensitivity first voltage threshold may be stopped. In this case, the first voltage threshold may be adjusted (updated) to a lower voltage, and the first sensitivity may be adjusted to a lower sensitivity. This prevents unnecessary switching to the emergency power source and prevents unnecessary discharge of the emergency power source (electricity storage device).

(13) The uninterruptible power supply device according to any one of (1) to (12) above may include a transmission unit that transmits operational information including a judgment history of the judgment unit and an update history of the threshold information.

According to the uninterruptible power supply device of (13) above, operational information including the judgment history of the judgment unit and the update history of the threshold information is transmitted, so that the operational information of the uninterruptible power supply device can be utilized.

(14) An uninterruptible power supply management system according to one embodiment of the present invention may include an operation database that records operation information transmitted by each of the uninterruptible power supplies described above, and a transmission unit that transmits the operation information recorded in the operation database to a specified terminal device based on a remote instruction from a customer.

According to an uninterruptible power supply management system according to one embodiment of the present invention, the operational information of each uninterruptible power supply device recorded in the operational database can be transmitted to, for example, a customer's terminal device, making it possible to provide the customer with valuable operational information collected through remote monitoring as a reference for the design of electrical room systems.

Below, embodiments of an uninterruptible power supply, an uninterruptible power supply management system, and a method for controlling an uninterruptible power supply will be described with reference to the drawings.

Figure 1 is a diagram showing an example of the configuration of an uninterruptible power supply 100. The uninterruptible power supply 100 (also called an uninterruptible power supply (UPS)) includes a switch (also called an AC switch) 20, a bidirectional converter 30, a current sensor 40, and a control unit 50.

A switch 20 is provided in the electrical path between the input terminal 11 and the output terminal 12. An input voltage (AC) is supplied to the input terminal 11 from an AC power source 1 in the power system. The input voltage supplied to the input terminal 11 is supplied to the AC load 2 from the output terminal 12 via the switch 20. The input voltage supplied to the input terminal 11 is supplied to the control unit 50. The control unit 50 can acquire the input voltage.

The electric path between the switch 20 and the output terminal 12 is branched, and the branched electric path is connected to the AC side terminal 15. The AC side of the bidirectional converter 30 is connected to the AC side terminal 15. The DC side of the bidirectional converter 30 is connected to the DC side terminal 16. The DC side terminal 16 is connected to the storage device side terminal 14 through an electric path. The storage device side terminal 14 is connected to the storage device 4. The electric path between the DC side terminal 16 and the storage device side terminal 14 is branched, and the branched electric path is connected to the output terminal 13 via the current sensor 40. The DC load 3 is connected to the output terminal 13. The current sensor 40 detects the current output from the bidirectional converter 30 to the DC load 3. The DC load 3 is not essential, and the output terminal 13, the current sensor 40, and the DC load 3 may not be provided. In addition, in the example shown in FIG. 1, the storage device 4 is connected to the storage device side terminal 14, but instead of this configuration, the uninterruptible power supply 100 may be configured to include the storage device 4.

The bidirectional converter 30 includes, for example, a bridge circuit including multiple switching elements, a capacitor, and the like. The bidirectional converter 30 converts AC power and DC power in both directions. When the AC power source 1 is normal, the bidirectional converter 30 converts the AC power supplied from the AC power source 1 via the switch 20 into the desired DC power, and supplies the converted DC power to the DC load 3 and the storage device 4. When the AC power source 1 is abnormal, the electrical path is interrupted by the switch 20, and the bidirectional converter 30 converts the DC power supplied from the storage device 4 into the desired AC power, and supplies the converted AC power to the AC load 2.

The control unit 50 acquires the input voltage and determines whether the input voltage is normal or abnormal based on the acquired input voltage and threshold information. If the control unit 50 determines that the input voltage is abnormal, it interrupts the electrical circuit with the switch 20 and switches the source of power supplied to the AC load 2 from the AC power source 1 to the power storage device 4.

The operation of the uninterruptible power supply 100 will be outlined below. When the AC power supply 1 is normal, AC power is supplied from the AC power supply 1 to the uninterruptible power supply 100. The switch 20 is in the on state, and the AC power supplied to the input terminal 11 is supplied to the AC load 2 from the output terminal 12 via the switch 20, and is also supplied to the bidirectional converter 30 from the AC side terminal 15.

The bidirectional converter 30 converts AC power into the required DC power. The bidirectional converter 30 supplies the converted DC power from the output terminal 13 to the DC load 3, and also supplies it from the storage device side terminal 14 to the storage device 4.

The power storage device 4 is charged with the supplied DC power and stores backup power in the event of an abnormality. Of the DC power output from the bidirectional converter 30, the surplus DC power that is not consumed by the DC load 3 is supplied to the power storage device 4.

When the AC power supply 1 is abnormal, the control unit 50 turns off the switch 20 and controls the bidirectional converter 30 to perform a DC to AC conversion operation. This causes the storage device 4 to discharge, and the DC power supplied from the storage device 4 is converted to AC power by the bidirectional converter 30, and the converted AC power is supplied to the AC load 2. Furthermore, if the bidirectional converter 30 was supplying DC power to the DC load 3 when the AC power supply 1 was normal, the control unit 50 supplies the DC power supplied from the storage device 4 to the DC load 3.

The control unit 50 includes a control unit 51 that controls the entire control unit, a communication unit 52, a memory 53, an interface unit 54, and a storage unit 55.

The control unit 51 may be configured by incorporating a required number of IC (Integrated Circuit) chips, CPUs (Central Processing Units), MPUs (Micro-Processing Units), GPUs (Graphics Processing Units), etc. The control unit 51 may also be configured by combining DSPs (Digital Signal Processors), FPGAs (Field-Programmable Gate Arrays), etc.

The communication unit 52 is equipped with a communication module and has the function of performing wired or wireless communication with an external device.

The interface unit 54 includes an interface module and outputs control signals to the switch 20 and the bidirectional converter 30. The control signals include, for example, signals for controlling the opening and closing of the switch 20 and the operation of the bidirectional converter 30 (AC to DC conversion, DC to AC conversion, control of the output voltage and current values, start and stop control of operation, etc.). The interface unit 54 acquires the input voltage and the current detected by the current sensor 40.

The storage unit 55 can be configured, for example, with a hard disk or semiconductor memory, and stores a computer program 60 (program product) and required information (for example, threshold information, the result of determining whether the input voltage is normal or abnormal, etc.).

The computer program 60 may be downloaded from an external device via the communication unit 52 and stored in the storage unit 55. Also, the computer program 60 recorded on a recording medium (e.g., an optically readable disk storage medium such as a CD-ROM) may be read by a recording medium reading unit and stored in the storage unit 55.

The memory 53 can be configured with semiconductor memory such as SRAM (Static Random Access Memory), DRAM (Dynamic Random Access Memory), flash memory, etc. The computer program 60 can be expanded in the memory 53, and the control unit 51 can execute the computer program 60. The control unit 51 can execute processing defined by the computer program 60. In other words, the processing by the control unit 51 is also processing by the computer program 60.

Next, we will explain how the uninterruptible power supply 100 determines whether the input voltage is normal or abnormal.

The memory unit 55 stores multiple voltage thresholds and threshold information having multiple sensitivities corresponding to the multiple voltage thresholds. The control unit 51 has the functions of a detection unit and a determination unit, detects the input voltage, and determines whether the input voltage is abnormal based on the detected input voltage and the threshold information.

The threshold information uses, for example, a sensitivity corresponding to one voltage threshold so as not to detect momentary drops in the input voltage. Also, a sensitivity corresponding to another voltage threshold is used so as to enable rapid detection of power outages. In other words, the uninterruptible power supply 100 can achieve both rapid detection of power outages and prevention of erroneous detection. The details are explained below.

Figure 2 is a diagram showing a first example of the relationship between the input voltage and the threshold information. In Figure 2, the threshold information includes a first voltage threshold Th1, a first sensitivity S1 corresponding to the first voltage threshold Th1, and a second voltage threshold Th2 smaller than the first voltage threshold Th1, and a second sensitivity S2 corresponding to the second voltage threshold Th2 and having a sensitivity equal to or greater than the first sensitivity S1. The first voltage threshold Th1 is generated by multiplying the crest value of the input voltage by a first predetermined number (e.g., 20% to 30%) and subtracting the result from the crest value. The second voltage threshold Th2 can be generated by multiplying the crest value of the input voltage by a second predetermined number (e.g., 50% to 70%) and subtracting the result from the crest value.

As threshold information, a first voltage threshold Th1 with a high voltage and a first sensitivity S1 with a low sensitivity, and a second voltage threshold Th2 with a low voltage and a second sensitivity S2 with a high sensitivity are used. When the first voltage threshold Th1 is used, the sensitivity is low (first sensitivity S1), so momentary voltage drops (drops) where the degree of voltage drop is relatively small are not detected, and false detection can be prevented. When the second voltage threshold Th2 is used, the sensitivity is high (second sensitivity S2), so power outages where the degree of voltage drop is relatively large can be quickly detected.

Figure 3 shows a first example of input voltage anomaly determination based on the first voltage threshold Th1. The first sensitivity S1 corresponding to the first voltage threshold Th1 corresponds to a first detection time having a length of time according to the sensitivity, and the second sensitivity S2 corresponding to the second voltage threshold Th2 corresponds to a second detection time having a length of time according to the sensitivity. The first sensitivity with low sensitivity includes a long first detection time, and the second sensitivity with high sensitivity includes a short second detection time. The detection time is the time when the input voltage becomes equal to or less than the voltage threshold.

The control unit 51 may determine that the input voltage is abnormal if the input voltage is equal to or lower than the high-voltage first voltage threshold for a long first detection time. In other words, by lowering the first sensitivity S1 of the first voltage threshold Th1 (lengthening the first detection time), a momentary voltage drop (drop) where the degree of voltage drop is relatively small is not detected as an input voltage abnormality, thereby preventing erroneous detection.

Figure 4 is a diagram showing a first example of input voltage anomaly determination based on the second voltage threshold Th2. The control unit 51 may determine that the input voltage is abnormal if the input voltage is equal to or lower than the low-voltage second voltage threshold for a short second detection time. That is, by increasing the second sensitivity S2 of the second voltage threshold Th2 (shortening the second detection time), a power outage with a relatively large degree of voltage drop can be quickly detected as an input voltage anomaly. By making the second detection time as short as possible (the detection time can be 0, i.e. the delay time can be 0), a power outage can be detected more quickly.

Figure 5 is a diagram showing a second example of input voltage anomaly determination based on the second voltage threshold Th2. In the example of Figure 5, the second voltage threshold Th2 is used to prevent erroneous detection when the input voltage fluctuation is an instantaneous voltage drop. If the second voltage threshold Th2 is set to a relatively high value, the second sensitivity S2 corresponding to the second voltage threshold Th2 is highly sensitive, so there is a possibility that an instantaneous voltage drop in the input voltage may be erroneously detected. Therefore, by setting the second voltage threshold Th2 to a voltage that is considered to be a rare case of an instantaneous voltage drop (for example, about 30% to 50% of the peak value of the input voltage), it is possible to prevent erroneous detection based on the second voltage threshold Th2. Furthermore, even if the second voltage threshold Th2 is set in this way, cases in which an instantaneous voltage drop below the second voltage threshold Th2 occurs are rare, so this does not pose a problem in practical operation.

Figure 6 is a diagram showing a second example of input voltage anomaly determination based on the first voltage threshold Th1. In addition to relatively small instantaneous voltage drops and power outages, input voltage fluctuations can also include gradual voltage drops of a constant level over a certain period of time. Figure 6 shows a schematic example of how the input voltage varies slowly. Since the first sensitivity S1 corresponding to the first voltage threshold Th1 is low (the first detection time is long), a gradual voltage drop of a constant level over a certain period of time as shown in Figure 6 can be reliably detected to determine an input voltage anomaly. In this way, it can be seen that detection using the first voltage threshold Th1 is effective for voltage drops that are not detected using the second voltage threshold Th2.

Next, we will explain how to determine an abnormality in the input voltage using a comparative example.

Figure 7 is a diagram showing a first example of input voltage anomaly determination based on a voltage threshold in the case of a comparative example. In the comparative example, one voltage threshold is used. As shown in Figure 7, when the input voltage falls below the voltage threshold, a power outage is detected. For example, certain loads such as lighting equipment and pump equipment may have excessive inrush currents or startup currents at the start of operation or startup compared to the steady state, and voltage fluctuations in the input voltage are likely to occur. As shown in Figure 7, when the detection speed based on the voltage threshold is increased, the power outage detection becomes sensitive. Being sensitive means that even a relatively short-term instantaneous voltage drop is detected as a power outage. However, in reality, the voltage fluctuations due to the inrush current and startup current due to the load described above are the cause, and no power outage has occurred in the power system. This leads to a false detection situation.

Figure 8 is a diagram showing a second example of input voltage anomaly determination based on a voltage threshold in the case of a comparative example. In order to prevent a situation in which a momentary voltage drop as shown in Figure 7 is erroneously detected as a power outage, it is possible to provide a slight delay time to prevent overly sensitive detection, rather than immediately detecting an anomaly when the input voltage falls below the voltage threshold. In other words, if the time when the input voltage falls below the voltage threshold is within the delay time, it is determined to be a momentary voltage drop that does not affect the power grid, rather than a power outage. This makes it possible to prevent the detection of a relatively short momentary voltage drop. However, if a power outage actually occurs, it is necessary to wait for the delay time before making the determination, resulting in a situation in which the detection of the power outage is delayed due to the detection delay.

As illustrated in FIGS. 7 and 8, in the comparative example, it was necessary to prioritize either high-speed detection or prevention of erroneous detection. However, as illustrated in FIGS. 1 to 6, the uninterruptible power supply 100 of this embodiment uses threshold information having multiple voltage thresholds and multiple sensitivities corresponding to the multiple voltage thresholds. Specifically, a sensitivity corresponding to one voltage threshold is used so as not to detect an instantaneous drop in the input voltage, and a sensitivity corresponding to another voltage threshold is used so as to quickly detect a power outage, so that both high-speed detection of a power outage and prevention of erroneous detection can be achieved. In particular, when the uninterruptible power supply 100 of this embodiment is used for a specific load such as a lighting device or a pump device, even if an instantaneous drop in the input voltage occurs due to a startup current or an inrush current, erroneous detection as a power outage can be prevented.

In the above embodiment, the sensitivity corresponding to the voltage threshold was described as including the detection time, but the sensitivity also includes the number of detections per given time instead of the detection time.

Figure 9 is a diagram showing a second example of the relationship between the input voltage and the threshold information. In Figure 9, the threshold information includes a first voltage threshold Th1 and a first detection count (first sensitivity S1) corresponding to the first voltage threshold Th1, and a second voltage threshold Th2 smaller than the first voltage threshold Th1 and a second detection time (second sensitivity S2) corresponding to the second voltage threshold Th2 and shorter than the first detection time. That is, the first sensitivity S1 of low sensitivity includes a first detection count that is a large number per predetermined time, and the second sensitivity S2 of high sensitivity includes a second detection count that is a small number per predetermined time. The detection count is the number of times the input voltage becomes equal to or less than the voltage threshold, and is the number of times the input voltage becomes equal to or less than the voltage threshold from the time when the input voltage first becomes equal to or less than the voltage threshold until a predetermined time has elapsed. In Figure 9, the time width of a predetermined time from a certain timing is illustrated as a patterned area. As in the case of FIG. 2, the first voltage threshold Th1 is generated by multiplying the crest value of the input voltage by a first predetermined number (e.g., 20% to 30%) and subtracting the result from the crest value. The second voltage threshold Th2 can be generated by multiplying the crest value of the input voltage by a second predetermined number (e.g., 50% to 70%) and subtracting the result from the crest value.

The control unit 51 may determine that the input voltage is abnormal if the number of times the input voltage is equal to or less than the first high-voltage threshold is equal to or greater than the first detection count, which is the greater number of times. This prevents a momentary voltage drop (drop) where the degree of voltage drop is relatively small from being detected as an input voltage abnormality. This is because momentary voltage drops occur only rarely when the input voltage is equal to or less than the first high-voltage threshold. In other words, the control unit 51 can detect a certain level of voltage drop for a certain period of time that affects the load, as illustrated in FIG. 6.

The control unit 51 may determine that the input voltage is abnormal if the number of times the input voltage is equal to or less than the low-voltage second voltage threshold is equal to or greater than the second detection count, which is smaller. This allows a power outage in which the degree of voltage drop is relatively large to be detected as an input voltage abnormality quickly. This is because, during a power outage, the input voltage falls to or less than the low-voltage second voltage threshold, and the number of detections per given time is small, allowing for quick detection.

The control unit 51 has a function as a switching unit, and may switch the source of power supplied to the load when an abnormality in the input voltage is determined. For example, when the control unit 51 detects a voltage drop in which the input voltage is equal to or lower than a first voltage threshold, or when it detects a power outage in which the input voltage is equal to or lower than a second voltage threshold, it can switch the source of power supply to the AC load 2 from the AC power source 1 to the power storage device 4. This makes it possible to appropriately respond to a voltage drop of a certain level for a certain period of time that affects the load or a power outage, and to keep the required power supplied to the load by minimizing interruptions to the power supply.

Figure 10 is a diagram showing the relationship between the input voltage and threshold information in the case of three-phase AC. When AC power supply 1 is a single-phase AC power supply, there is a dead zone where the voltage threshold becomes 0 depending on the crest value of the input voltage, as shown in Figures 2 and 9. However, when AC power supply 1 is a three-phase AC power supply, the input voltages of phases 1, 2, and 3 are shifted by 120°, so there is no dead zone where the voltage threshold becomes 0 depending on the crest value of the input voltage.

Figure 11 is a diagram showing an example of a control method for the uninterruptible power supply 100. For convenience, the following description will be given with the control unit 51 as the subject of processing. The control unit 51 acquires the input voltage (S11), and determines whether the acquired input voltage is equal to or less than the first voltage threshold for the first detection time (S12). If the input voltage is equal to or less than the first voltage threshold (YES in S12), the control unit 51 determines that an instantaneous drop has occurred (S13), switches the power supply source from the input power source (AC power source 1) to the emergency power source (electricity storage device 4) (S14), and ends the process.

If the input voltage is not equal to or less than the first voltage threshold (NO in S12), the control unit 51 determines whether the acquired input voltage is equal to or less than the second voltage threshold during the second detection time (S15). If the input voltage is equal to or less than the second voltage threshold (YES in S15), the control unit 51 determines that a power outage has occurred (S16) and performs the process of step S14.

If the input voltage is not equal to or less than the second voltage threshold (NO in S15), the control unit 51 determines whether or not to end the process (S17). If the process is not to be ended (NO in S17), the control unit 51 continues the process from step S11 onwards. If the process is to be ended (YES in S17), for example, when the operation of the uninterruptible power supply 100 is stopped, the control unit 51 ends the process.

Next, we will explain the operation and management of the uninterruptible power supply 100.

Figure 12 is a diagram showing an example of the configuration of an uninterruptible power supply management system. The uninterruptible power supply management system includes a management server 300 and an operation record DB 310 connected to the management server 300. The management server 300 is a server operated by a management company that manages the operation of the uninterruptible power supply 100, and is connected to a communication network 5 such as the Internet. A communication device 200 is connected to the communication network 5, and a plurality of uninterruptible power supplies 100 are connected to the communication device 200 via wired communication or wireless communication. The communication device 200 transmits operation information acquired from the uninterruptible power supply 100 to the management server 300. The communication device 200 can be installed, for example, at each base (for example, a tunnel, a factory, a business office, etc.). In the example of Figure 12, two communication devices 200 are illustrated, but the number of communication devices 200 may be three or more. A terminal device 320 and a terminal device 400 are connected to the communication network 5. The terminal device 320 is a terminal device used by an administrator who manages the operation of the uninterruptible power supply 100. The terminal device 400 is a terminal device used by a customer of a client company that owns the uninterruptible power supply device 100. The terminal device 320 and the terminal device 400 can be configured, for example, as a personal computer, a tablet terminal, or a smartphone.

The communication unit 52 of the uninterruptible power supply 100 has a function as a receiving unit, and may remotely receive an update command for the threshold information from the terminal device 320. The control unit 51 has a function as an updating unit, and may update the threshold information stored in the memory unit 55 based on the received update command. Since the threshold information can be updated based on a remote command, the threshold information is not fixed, and it is possible to adjust the threshold information according to the status of the power system that supplies the input voltage.

The control unit 51 has a function as an update history collection unit, and may collect a history of updates (update history) of threshold information based on received update commands in the storage unit 55. Since historical information of threshold information can be collected based on commands from a remote location, for example, threshold information that has been reviewed periodically or non-periodically depending on the status of the power system that supplies the input voltage can be stored as operational performance.

The control unit 51 may function as a judgment history collection unit and collect judgment histories of input voltage anomalies in the storage unit 55. By collecting judgment histories, the transition of the status of the power system that supplies the input voltage can be saved as operational performance.

The control unit 51 may update the threshold information stored in the memory unit 55 based on the input voltage abnormality determination history.

Figure 13 is a diagram showing an example of updating threshold information based on judgment history. In case 1, detection occurs frequently at the first voltage threshold before the update (for example, detection occurs several times within several hours), and detection does not occur at the second voltage threshold before the update. In case 1, if a power outage does not actually occur, it is considered that momentary drops due to input voltage fluctuations caused by the startup current or inrush current of a specific load have occurred continuously. In order to prevent unnecessary switching of the power supply source, it is possible to update either the first voltage threshold or the first sensitivity, or both. For situations where false detections occur frequently, the threshold information can be adjusted to reduce false detections.

In case 2, detection occurs frequently at the second voltage threshold before the update (e.g., once every few days, once a week, once every few weeks, etc.), but detection does not occur at the first voltage threshold before the update. In case 2, if no power outage actually occurs, a possible cause may be a power shortage in the power grid. In order to prevent unnecessary switching of the power supply source, it is possible to update either the second voltage threshold or the second sensitivity, or both. This makes it possible to adjust the threshold information so as to prevent unnecessary switching of the power supply source due to a problem in the power grid.

Although not shown, it is assumed that detection has occurred at the second voltage threshold before the update (e.g., several times in the past), but detection has not occurred at the first voltage threshold before the update. In case 2, it is assumed that a power outage actually occurred and affected the load. In such a case, it is possible to update either the second voltage threshold or the second sensitivity, or both. This makes it possible to adjust the threshold information so as to shorten the time to detect a power outage and further shorten the delay time for switching the power supply source. In other words, the threshold information can be adjusted to allow for faster detection in a situation where a power outage occurs.

The control unit 51 may function as a stop unit and stop the determination of an abnormality in the input voltage based on one of the multiple voltage thresholds and the multiple sensitivities corresponding to the multiple voltage thresholds. For example, as in case 1 of FIG. 13, when a situation occurs in which an abnormality in the input voltage is detected (determined) based on the low-sensitivity first voltage threshold with a certain frequency and an abnormality in the input voltage is not detected (determined) based on the high-sensitivity second voltage threshold, and there is no effect on the load (voltage drop is allowed), the determination of an abnormality in the input voltage based on the low-sensitivity first voltage threshold may be stopped. This can suppress unnecessary switching to the emergency power source (electricity storage device 4) and unnecessary discharge of the emergency power source (electricity storage device 4).

Also, as in case 2, when a situation occurs in which an input voltage abnormality is detected (determined) based on the high-sensitivity second voltage threshold with a certain frequency, and an input voltage abnormality is not detected (determined) based on the low-sensitivity first voltage threshold, if there is no effect on the load (voltage drop is acceptable), the input voltage abnormality determination based on the high-sensitivity second voltage threshold may be stopped. This makes it possible to suppress unnecessary switching to the emergency power source (electricity storage device 4) and unnecessary discharge of the emergency power source (electricity storage device 4).

The control unit 51 may transmit operation information including the judgment history and the update history of the threshold information to the management server 300 via the communication unit 52 (also referred to as the transmission unit). Since the operation information including the judgment history and the update history of the threshold information is transmitted, the operation information of the uninterruptible power supply 100 can be utilized. The operation information may be transmitted each time a predetermined period (e.g., one month) has passed, each time the amount of data of the operation information exceeds a predetermined amount, or each time a transmission request is received from the administrator's terminal device 320.

Figure 14 is a diagram showing an example of operational information. The operational information may include the judgment history and threshold information update history for each uninterruptible power supply 100 in the base, collected through the communication device 200 at the base. As shown in Figure 14, the operational information includes the content of an event and the date and time of the event for each uninterruptible power supply (UPS1, UPS2, UPS3, ...) in the base. Events include, for example, updates of the first voltage threshold, first sensitivity, second voltage threshold, second sensitivity, detection of a momentary drop in input voltage, detection of a power outage in input voltage, etc. In the figure, a check mark indicates that an event has occurred, and a horizontal bar indicates that an event has not occurred.

The management server 300 may record the operational information transmitted by each of the uninterruptible power supplies 100 via the communication device 200 in an operational history DB 310 (also referred to as an operational database). Furthermore, when the management server 300 receives a remote instruction from a customer from the terminal device 400, it may transmit the operational information recorded in the operational history DB 310 to the terminal device 400. By transmitting the operational information of each of the uninterruptible power supplies 100 recorded in the operational history DB 310 to, for example, the customer's terminal device 400, valuable operational information collected through remote monitoring can be provided to the customer as a reference for the design of the electrical room system.

REFERENCE SIGNS LIST 1 AC power supply 2 AC load 3 DC load 4 Power storage device 5 Communication network 20 Switch 30 Bidirectional converter 50 Control unit 51 Control unit 52 Communication unit 53 Memory 54 Interface unit 55 Storage unit 60 Computer program 100 Uninterruptible power supply 200 Communication device 300 Management server 310 Operational performance DB
320, 400 Terminal device

Claims (16)

a storage unit that stores threshold information having a plurality of voltage thresholds and a plurality of sensitivities corresponding to the plurality of voltage thresholds;
A detection unit that detects an input voltage;
a determination unit that determines an abnormality in the input voltage based on the input voltage detected by the detection unit and the threshold value information,
Uninterruptible power system. The threshold information is
a first sensitivity corresponding to a first voltage threshold and the first voltage threshold, and a second sensitivity corresponding to a second voltage threshold less than the first voltage threshold and the second voltage threshold, the second sensitivity being equal to or greater than the first sensitivity;
2. The uninterruptible power supply of claim 1. the first sensitivity and the second sensitivity each include a first detection time and a second detection time that is equal to or shorter than the first detection time;
The determination unit is
When the input voltage detected by the detection unit is equal to or lower than the first voltage threshold for the first detection time, the input voltage is determined to be abnormal.
3. An uninterruptible power supply according to claim 2. The determination unit is
When the input voltage detected by the detection unit is equal to or lower than the second voltage threshold for the second detection time, the input voltage is determined to be abnormal.
4. An uninterruptible power supply according to claim 3. the first sensitivity and the second sensitivity each include a first detection count per predetermined time and a second detection count that is equal to or less than the first detection count,
The determination unit is
When the number of times that the input voltage detected by the detection unit is equal to or less than the first voltage threshold is equal to or greater than the first detection number, it is determined that the input voltage is abnormal.
5. An uninterruptible power supply according to claim 4. The determination unit is
When the number of times that the input voltage detected by the detection unit is equal to or less than the second voltage threshold is equal to or greater than the second detection number, it is determined that the input voltage is abnormal.
6. An uninterruptible power supply according to claim 5. and a switching unit that switches a power supply source to be supplied to a load when the determination unit determines that an abnormality has occurred in the input voltage.
An uninterruptible power supply according to any one of claims 1 to 6. A receiving unit that remotely receives an update command for the threshold information;
an update unit that updates the threshold information stored in the storage unit based on an update command received by the receiving unit,
An uninterruptible power supply according to any one of claims 1 to 6. A receiving unit that remotely receives an update command for the threshold information;
an update history collection unit that collects an update history of threshold information based on the update command received by the receiving unit,
An uninterruptible power supply according to any one of claims 1 to 6. A determination history collection unit is provided to collect a determination history of the determination unit.
An uninterruptible power supply according to any one of claims 1 to 6. an update unit that updates the threshold information stored in the storage unit based on the determination history;
11. An uninterruptible power supply according to claim 10. a stop unit that stops the determination of an abnormality in the input voltage by the determination unit based on one of the plurality of voltage thresholds and one of the plurality of sensitivities corresponding to the plurality of voltage thresholds, based on the determination history;
11. An uninterruptible power supply according to claim 10. a transmission unit that transmits operation information including a determination history of the determination unit and an update history of the threshold information,
An uninterruptible power supply according to any one of claims 1 to 6. an operation database for recording operation information transmitted by each of the uninterruptible power supplies according to claim 13;
a transmission unit that transmits the operation information recorded in the operation database to a predetermined terminal device based on a remote instruction from a customer.
Uninterruptible power supply management system. On the computer,
Get the input voltage,
determining whether the input voltage is abnormal based on the acquired input voltage, and threshold information having a plurality of voltage thresholds and a plurality of sensitivities corresponding to the plurality of voltage thresholds;
A computer program that executes a process. storing threshold information having a plurality of voltage thresholds and a plurality of sensitivities corresponding to the plurality of voltage thresholds;
Detects the input voltage,
determining whether the input voltage is abnormal based on the detected input voltage and the threshold information;
A method for controlling an uninterruptible power supply.

Images