Backup device, backup device control method, and computer system

Abstract

To provide a backup device, a backup device control method, and a computer system that extend life of a backup capacitor used in a backup device.SOLUTION: A backup device 10 includes a backup capacitor 16, a bidirectional power supply circuit 15, and a control unit 13. The backup capacitor is composed of a supercapacitor that stores electrical energy for backup. The bidirectional power supply circuit charges the backup capacitor with power from a power supply line and supplies power to the power supply line with power discharged from the backup capacitor. The control unit controls charging and discharging of the backup capacitor in the bidirectional power supply circuit according to the voltage of the power supply line, and also performs control to adjust an applied voltage when charging the backup capacitor according to power consumption of an apparatus connected to the power supply line.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a backup device, a control method for a backup device, and a computer system. [Background technology]

[0002] Backup power supplies are used to temporarily supply power to loads in the event of a power outage. Supercapacitors, which have features such as a high allowable number of charge / discharge cycles, are often used as the storage element for these backup power supplies. However, because these supercapacitors are chemical components, they deteriorate with use and their capacity decreases. Typically, when the capacity drops 30% from its initial state, it is considered to have reached the end of its life and is replaced.

[0003] In order to reduce the frequency of replacing storage elements in such backup power supplies, technologies for extending the life of storage elements have been proposed. For example, a system has been proposed that includes multiple backup capacitors as storage elements and switches the multiple backup capacitors on or off based on backup energy requirements based on the power consumption of a load device (see, for example, Patent Document 1). In this system, when the power supply to the device is interrupted, one of the multiple backup capacitors that is in an on state supplies backup energy to the device. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2018-181348 Summary of the Invention [Problem to be solved by the invention]

[0005] In the above conventional description, the on-time and off-time of multiple backup capacitors are equalized to equalize the lifespan of all supercapacitors, but there is a problem in that it does not address the issue of extending the lifespan of each backup capacitor.

[0006] The present disclosure provides a technique for extending the life of a backup capacitor used in a backup device. [Means for solving the problem]

[0007] A backup device according to one aspect of the present disclosure includes a backup capacitor, a bidirectional power supply circuit, and a control unit. The backup capacitor is a supercapacitor that stores electrical energy for backup. The bidirectional power supply circuit charges the backup capacitor with power from a power supply line and supplies power to the power supply line with the power discharged from the backup capacitor. The control unit controls charging and discharging of the backup capacitor in the bidirectional power supply circuit according to the voltage of the power supply line, and also controls adjusting the applied voltage when charging the backup capacitor according to the power consumption of a device connected to the power supply line. [Effects of the Invention]

[0008] According to the present disclosure, the life of the backup capacitor can be extended. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram illustrating an example of the configuration of a backup device according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a diagram illustrating an example of a display according to an embodiment of the present disclosure. [Figure 3] FIG. 3 is a diagram illustrating an example of characteristics of a supercapacitor according to an embodiment of the present disclosure. [Figure 4] FIG. 4 is a diagram illustrating an example of characteristics of a supercapacitor according to an embodiment of the present disclosure. [Figure 5]FIG. 5 is a diagram illustrating an example of a processing procedure of the charging process according to the first embodiment of the present disclosure. [Figure 6] FIG. 6 is a diagram showing another example of the processing procedure of the charging process according to the first embodiment of the present disclosure. [Figure 7] FIG. 7 is a diagram illustrating an example of a processing procedure of a charging process according to the second embodiment of the present disclosure. [Figure 8] FIG. 8 is a diagram illustrating an example of a processing procedure of a charging process according to the third embodiment of the present disclosure. [Figure 9] FIG. 9 is a diagram illustrating an example of a processing procedure of a capacity calculation process according to the third embodiment of the present disclosure. [Figure 10] FIG. 10 is a diagram showing another example of the processing procedure of the charging process according to the third embodiment of the present disclosure. [Figure 11] FIG. 11 is a diagram illustrating an example of a processing procedure of a load information acquisition process according to the third embodiment of the present disclosure. [Figure 12] FIG. 12 is a diagram illustrating an example of a processing procedure of the charging process according to the third embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. The description will be given in the following order. In the following embodiments, the same components are designated by the same reference numerals, and redundant description will be omitted. 1. First embodiment 2. Second embodiment 3. Third embodiment

[0011] (1. First embodiment) [Backup device configuration] FIG. 1 is a diagram illustrating an example configuration of a backup device according to an embodiment of the present disclosure. The figure is a block diagram illustrating an example configuration of a backup device 10. The figure further illustrates a power supply 30, a PC (personal computer) 40, and a cooling unit 50. The backup device 10 supplies power to a load such as a PC 40 during a power outage. Normally, power is supplied to the PC 40 from the power supply 30. If the power supply from the power supply 30 is interrupted, the backup device 10 temporarily supplies power. During this time, the PC 40 performs processing such as shutdown. In other words, the backup device 10 supplies power while the PC 40 is undergoing processing such as shutdown.

[0012] During normal operation, the backup device 10 receives power from the power source 30 and charges the built-in storage element. During a power outage, the backup device 10 discharges the built-in storage element to supply power to the PC 40. A backup capacitor made of a supercapacitor can be used as this storage element. A supercapacitor is also called an electric double layer capacitor.

[0013] As mentioned above, supercapacitors deteriorate with use, decreasing their capacitance and increasing their internal resistance. Typically, a supercapacitor's lifespan is defined as reaching the end of its life when its capacitance decreases by 30% from its initial state. Supercapacitor degradation is affected by the ambient temperature, the duration of voltage application, and the applied voltage. For example, a 10°C increase in ambient temperature halves the supercapacitor's lifespan. This is because the electrolyte inside the supercapacitor is strongly affected by temperature. The lifespan of a supercapacitor can be extended by detecting an increase in the ambient temperature, stopping the application of voltage, and cooling the supercapacitor.

[0014] Furthermore, the longer the voltage is applied to a supercapacitor, the shorter its lifespan will be. Therefore, by monitoring the time that voltage is applied to the supercapacitor and stopping the application of voltage at regular intervals, the lifespan of the supercapacitor can be extended.

[0015] Furthermore, the lifespan of a supercapacitor can be extended by using it at an applied voltage lower than the rated voltage. In this case, increasing the applied voltage can also compensate for the decrease in capacitance due to degradation. The lifespan of a supercapacitor can also be extended by adjusting the applied voltage according to the load being backed up. Specifically, the applied voltage is lowered when the load on the PC40 is light, and increased when the load becomes heavy. This makes it possible to maintain the backup power capacity at an optimum state while extending the lifespan of the supercapacitor.

[0016] The capacitance of a supercapacitor can be measured by the discharge time when the supercapacitor is forcibly discharged while the backup target device is in a stopped state. The degree of deterioration of the supercapacitor can be determined based on the change (decrease) in capacitance based on this measurement.

[0017] The backup device 10 includes a backflow prevention circuit 11, a switch 12, a control unit 13, a bidirectional power supply circuit 15, a backup capacitor 16, a discharge circuit 17, a temperature sensor 18, a real-time clock 19, and a display unit 20. The backup device 10 also includes a cooling unit 50.

[0018] In the figure, thick arrows represent power supply paths. Here, the power supply paths of the power supply 30, backflow prevention circuit 11, switch 12, and PC 40 constitute a power supply line. Thin arrows represent the movement of control signals and data. White arrows represent the direction of movement of electrical energy.

[0019] The power supply 30 inputs a predetermined power supply voltage (for example, 5V) to the PC 40 and the backup device 10. The power supply 30 is assumed to be, for example, a power supply unit such as an AC adapter.

[0020] The backflow prevention circuit 11 prevents the power supply voltage during backup from being applied to the output of the power supply 30. When the power supply from the power supply 30 is cut off and the backup device 10 enters backup mode, a voltage is applied to the power supply line from the bidirectional power supply circuit 15, which will be described later. The backflow prevention circuit 11 can prevent this voltage from being applied to the power supply 30.

[0021] The switch 12 is inserted into the power supply line to turn on and off the supply of power to the PC 40. For example, a MOS transistor can be used for the switch 12. A control signal from the control unit 13 is input to a control terminal of the switch 12.

[0022] The backup capacitor 16 stores electrical energy for backup purposes.

[0023] The bidirectional power supply circuit 15 charges the backup capacitor 16 with power from the power supply line and supplies power to the power supply line with the power discharged from the backup capacitor 16 .

[0024] The discharge circuit 17 discharges the backup capacitor 16. The discharge circuit 17 discharges the backup capacitor 16 under the control of the control unit 13.

[0025] The real-time clock 19 counts the voltage application time and the like under the control of the control unit 13 .

[0026] The temperature sensor 18 measures the environmental temperature and outputs the measured environmental temperature to the control unit 13. The temperature sensor 18 can be disposed near the backup capacitor 16.

[0027] The cooling unit 50 cools the backup capacitor 16. The cooling unit 50 can be configured, for example, by a cooling fan.

[0028] The display unit 20 displays status information of the backup power supply system (the voltage of the backup capacitor 16, the ambient temperature, and the rotation speed of the cooling fan).

[0029] The control unit 13 controls the entire backup device 10. The control unit 13 in the figure includes an LED (Light Emitting Diode) 14.

[0030] Under normal circumstances, the control unit 13 turns on the switch 12 to supply power to the PC 40. At this time, the bidirectional power supply circuit 15 charges the backup capacitor 16. If the power supply from the power source 30 is cut off due to a power outage or the like, the backup device 10 transitions to backup mode. The bidirectional power supply circuit 15 discharges the backup capacitor 16 to generate a power supply voltage from the stored electrical energy and supplies it to the power supply line. At this time, the power is also supplied to the PC 40 via the switch 12. At this time, the control unit 13 also issues a shutdown command to the PC 40, causing the PC 40 to shut down during backup.

[0031] After the PC 40 completes the shutdown, it sends a shutdown completion flag to the control unit 13. The control unit 13, upon receiving this flag, stops the bidirectional power supply circuit 15. By performing the above process, devices such as the PC 40 can be safely shut down even in the event of a power outage. The backup time can be set to, for example, 10 seconds.

[0032] The control unit 13 monitors the temperature of the backup capacitor 16 via a temperature sensor 18. The control unit 13 also monitors the voltage of the backup capacitor 16. The control unit 13 also obtains time information from a real-time clock 19 and monitors the time that a voltage is being applied to the backup capacitor 16 (voltage application time). The control unit 13 uses information on the temperature, voltage, and voltage application time of the backup capacitor 16 to perform control to extend the life of the backup capacitor 16.

[0033] The control unit 13 also controls the cooling unit 50. Specifically, the control unit 13 controls the cooling fan of the cooling unit 50 to rotate at a desired number of revolutions.

[0034] Furthermore, the control unit 13 outputs the voltage of the backup capacitor 16, the ambient temperature, and the rotation speed of the cooling fan to the display unit 20.

[0035] [display] 2 is a diagram showing an example of a display according to an embodiment of the present disclosure. The figure shows an example of a display on a display screen 100 of the display unit 20. Status information is displayed in an area 110.

[0036] [Supercapacitor characteristics] 3 and 4 are diagrams illustrating an example of the characteristics of a supercapacitor according to an embodiment of the present disclosure. FIG. 3 is a diagram illustrating the relationship between elapsed time and the rate of capacitance decrease of a supercapacitor used in the backup capacitor 16. The horizontal axis of FIG. 3 represents elapsed time. The vertical axis of FIG. 3 represents the rate of capacitance decrease. As shown in FIG. 3, the capacitance of a supercapacitor decreases over time. In the example shown in the figure, the capacitance decreases by -30%, which is the lifespan of the supercapacitor, after 3000 hours.

[0037] By monitoring the time that voltage is applied to the supercapacitor and increasing the applied voltage after a certain time has elapsed, it is possible to compensate for the decrease in capacitance of the supercapacitor due to degradation. If the capacitance of the supercapacitor is C and the applied voltage is V, the charge Q of the supercapacitor can be expressed by the following equation: Q=C×V As a result, even if the capacitance of the supercapacitor decreases due to degradation, the amount of charge corresponding to the amount of stored electricity can be kept constant by increasing the applied voltage.

[0038] Figure 4 shows an example of compensating for a decrease in the amount of stored energy by adjusting the applied voltage. Supercapacitors have a rated voltage and must be used at or below the rated voltage. Using a supercapacitor at a voltage below the rated voltage also extends its lifespan. For example, assume a supercapacitor has a rated voltage of 3V and a capacitance of 10F. As shown in Figure 4, if the initial applied voltage is 2.3V, the amount of stored energy is 23Q. The storage rate at this point is assumed to be 100%. When the capacitance subsequently decreases by 5% to 9.5F due to degradation, the applied voltage is changed to 2.4V. The amount of stored energy becomes 22.8Q, and the storage rate is 99.1%. When the supercapacitor further deteriorates and the capacitance decreases by 10% to 9F, the applied voltage is changed to 2.5V. This process is repeated. Even if the capacitance of the supercapacitor decreases by 30% from its initial state, the amount of stored energy can be maintained at approximately the same level as the initial state by changing the applied voltage to the rated voltage (2.9V).

[0039] [Charging process] FIG. 5 is a diagram showing an example of a processing procedure for charging processing according to the first embodiment of the present disclosure. The same figure is a flowchart showing an example of a processing procedure for charging processing of the backup capacitor 16 in the backup device 10. First, the control unit 13 initializes the voltage application time (step S101). Next, the control unit 13 causes the bidirectional power supply circuit 15 to start applying a voltage to the backup capacitor 16 (step S102). Next, the control unit 13 causes the real-time clock 19 to count the voltage application time (step S103). Next, the control unit 13 determines whether the voltage application time has reached a set time (step S104). Here, the set time may be, for example, the time it takes for the capacitance of the backup capacitor 16 to decrease by 5%. If the voltage application time has not reached the set time (step S104, No), the control unit 13 proceeds to the processing of step S103.

[0040] On the other hand, if the voltage application time has reached the set time (step S104, Yes), the control unit 13 increases the applied voltage (step S105). This can be done by the control unit 13 controlling the bidirectional power supply circuit 15 to increase the output voltage. Thereafter, the control unit 13 proceeds to the process of step S102.

[0041] In this way, by adjusting the applied voltage during charging, it is possible to reduce the decrease in the amount of stored electricity due to a decrease in the capacitance of the supercapacitor that constitutes the backup capacitor 16. This makes it possible to extend the life of the backup capacitor 16.

[0042] [Other charging processes] FIG. 6 is a diagram showing another example of the processing procedure of the charging process according to the first embodiment of the present disclosure. The same figure is a flowchart showing an example of the processing procedure of the charging process of the backup capacitor 16 in the backup device 10. First, the control unit 13 causes the bidirectional power supply circuit 15 to start applying a voltage to the backup capacitor 16 (step S111). Next, the control unit 13 causes the real-time clock 19 to count the voltage application time (step S112). Next, the control unit 13 determines whether the voltage application time has reached a set time (step S113). Here, the set time can be, for example, one hour. If the voltage application time has not reached the set time (step S113, No), the control unit 13 proceeds to the processing of step S112.

[0043] On the other hand, if the voltage application time has reached the set time (step S113, Yes), the control unit 13 causes the bidirectional power supply circuit 15 to stop applying voltage to the backup capacitor 16 (step S114). Next, the control unit 13 determines whether the stop time has reached the set time (step S115). Here, the set time may be, for example, one minute. If the stop time has not reached the set time (step S115, No), the control unit 13 waits until the stop time reaches the set time (step S115). On the other hand, if the stop time has reached the set time (step S115, Yes), the control unit 13 proceeds to the process of step S111.

[0044] In this way, in the above process, the application of voltage to the backup capacitor 16 is stopped at predetermined time intervals. At this time, the backup capacitor 16 is not in the discharge mode, so even if the application of voltage is stopped, the decrease in the accumulated charge is considered to be slight (similar to natural discharge), and there is no impact on the backup. In addition, by obtaining the amount of natural discharge per unit time in advance, the time at which the application of voltage can be stopped can be obtained.

[0045] By extending the time that voltage application is stopped, the life of the backup capacitor 16 can be extended. It is also possible to monitor the terminal voltage of the backup capacitor 16 while voltage application is stopped, and resume voltage application when it falls below the voltage required for backup. In this case, it is necessary to leave a certain degree of margin for the voltage required for backup. For example, if the applied voltage is 2.3 V, the voltage required for backup should be 2.2 V.

[0046] In this way, by applying a voltage to the backup capacitor 16 intermittently during charging, it is possible to ensure a period of time during which no voltage is applied to the supercapacitor that constitutes the backup capacitor 16. This makes it possible to extend the life of the backup capacitor 16.

[0047] (2. Second Embodiment) The backup device 10 of the first embodiment described above adjusts the applied voltage or the voltage application time during charging. In contrast, the backup device 10 of the second embodiment of the present disclosure differs from the first embodiment described above in that it cools the backup capacitor 16.

[0048] [Charging process] FIG. 7 is a diagram showing an example of a processing procedure for charging according to the second embodiment of the present disclosure. This figure is a flowchart showing an example of a processing procedure for charging the backup capacitor 16 in the backup device 10. First, the control unit 13 sets the rotation speed of the cooling fan of the cooling unit 50 to a steady rotation speed (step S121). Next, the control unit 13 causes the bidirectional power supply circuit 15 to start applying a voltage to the backup capacitor 16 (step S122). Next, the control unit 13 causes the temperature sensor 18 to measure the ambient temperature (step S123). Next, the control unit 13 determines whether the ambient temperature has reached a set temperature (step S124). Here, the set temperature may be, for example, 10° C. higher than the normal temperature. If the ambient temperature has not reached the set temperature (step S124, No), the control unit 13 proceeds to the processing of step S122.

[0049] On the other hand, if the ambient temperature has reached the set temperature (step S124, Yes), the control unit 13 causes the bidirectional power supply circuit 15 to stop applying voltage to the backup capacitor 16 (step S125). Next, the control unit 13 increases the rotation speed of the cooling fan of the cooling unit 50 (step S126). This increases the airflow rate of the cooling fan. Next, the control unit 13 determines whether the ambient temperature is below the set temperature (step S127). Here, the set temperature may be, for example, the temperature during normal use. If the ambient temperature is equal to or higher than the set temperature (step S127, No), the control unit 13 proceeds to the process of step S125.

[0050] On the other hand, if the ambient temperature is lower than the set temperature (Yes at step S127), the control unit 13 proceeds to the process at step S121.

[0051] In the above process, it is also possible to perform control to synchronize the rotation speed of the cooling fan with the temperature acquired by the temperature sensor 18. In other words, it is also possible to change the rotation speed of the cooling fan according to the temperature.

[0052] In this way, in the above process, the rotation speed of the cooling fan of the cooling unit 50 is adjusted in accordance with the rise in temperature of the backup capacitor 16. This reduces the temperature rise of the supercapacitor that constitutes the backup capacitor 16, thereby extending the life of the backup capacitor 16.

[0053] (3. Third Embodiment) In the third embodiment of the present disclosure, an example of a backup device 10 that acquires the capacitance of a backup capacitor 16 will be described.

[0054] [Charging process] FIG. 8 is a diagram showing an example of a processing procedure for charging according to the third embodiment of the present disclosure. The figure is a flowchart showing an example of a processing procedure for charging the backup capacitor 16 in the backup device 10. First, the control unit 13 causes the bidirectional power supply circuit 15 to start applying a voltage to the backup capacitor 16 (step S131). Next, the control unit 13 determines whether the voltage of the backup capacitor 16 is equal to or greater than a threshold (step S132). Here, the threshold may be, for example, 2.5 V. If the voltage of the backup capacitor 16 is not equal to or greater than the threshold (step S132, No), the control unit 13 proceeds to processing in step S133. On the other hand, if the voltage of the backup capacitor 16 is equal to or greater than the threshold (step S132, Yes), the control unit 13 proceeds to processing in step S136.

[0055] In step S133, the control unit 13 determines whether the device requiring backup is operating (step S133). If the device requiring backup is operating (step S133, Yes), the control unit 13 proceeds to the process of step S131. On the other hand, if the device requiring backup is not operating (step S133, No), the control unit 13 causes the bidirectional power supply circuit 15 to start applying a voltage to the backup capacitor 16 (step S134). Next, the control unit 13 determines whether the voltage of the backup capacitor 16 is equal to or greater than a threshold (step S135). If the voltage of the backup capacitor 16 is not equal to or greater than the threshold (step S135, No), the control unit 13 proceeds to the process of step S134. On the other hand, if the voltage of the backup capacitor 16 is equal to or greater than the threshold (step S135, Yes), the control unit 13 proceeds to the process of step S131 via a capacitance calculation process (step S140).

[0056] In step S136, the control unit 13 determines whether the device requiring backup is operating (step S136). If the device requiring backup is operating (step S136, Yes), the control unit 13 causes the bidirectional power supply circuit 15 to stop applying voltage to the backup capacitor 16 (step S137), and proceeds to the processing of step S132. On the other hand, if the device requiring backup is not operating in step S136 (step S136, No), the control unit 13 proceeds to the processing of step S131 via a capacitance calculation processing (step S140).

[0057] [Capacity calculation process] FIG. 9 is a diagram showing an example of a processing procedure of a capacity calculation process according to the third embodiment of the present disclosure. This figure is a flowchart showing an example of the processing procedure of the capacity calculation process (step S140) of FIG. 8. First, the control unit 13 causes the discharge circuit 17 to discharge the backup capacitor 16 (step S141). Next, the control unit 13 calculates the capacitance of the supercapacitor constituting the backup capacitor 16 based on the discharge time (step S142). Next, the control unit 13 determines whether the capacitance is equal to or greater than a threshold (step S143). If the capacitance is equal to or greater than the threshold (step S143, Yes), the control unit 13 returns to the original processing. On the other hand, if the capacitance is not equal to or greater than the threshold (step S143, No), the control unit 13 performs a replacement process (step S144). Specifically, a replacement instruction is output to the outside of the backup device 10. Then, the control unit 13 returns to the original processing.

[0058] In this way, if the voltage of backup capacitor 16 reaches a preset voltage and the PC 40 requiring backup is operating, the application of voltage to backup capacitor 16 is stopped. If the voltage of backup capacitor 16 subsequently falls below the preset voltage, voltage is applied to backup capacitor 16 again. If the PC 40 requiring backup is shut down and stopped during this cycle, voltage is applied to backup capacitor 16 once to charge it up to the preset voltage. Then, backup capacitor 16 is forcibly discharged using discharge circuit 17, and the capacitance of the supercapacitor constituting backup capacitor 16 is calculated by measuring the discharge time.

[0059] A similar measurement is performed before shipping the product to obtain the initial capacitance, and then the capacitance of the backup capacitor 16 after use is calculated to detect changes in capacitance, which makes it possible to determine the deterioration of the supercapacitor that constitutes the backup capacitor 16.

[0060] [Other charging processes] Fig. 10 is a diagram showing another example of the processing procedure of the charging processing according to the third embodiment of the present disclosure. The processing in Fig. 10 is a combination of the processing in Fig. 5 and Fig. 8. First, the control unit 13 initializes the voltage application time (step S151). Next, the control unit 13 causes the bidirectional power supply circuit 15 to start applying a voltage to the backup capacitor 16 (step S152). Next, the control unit 13 determines whether the voltage of the backup capacitor 16 is equal to or greater than a threshold value (step S153). If the voltage of the backup capacitor 16 is not equal to or greater than the threshold value (step S153, No), the control unit 13 proceeds to the processing in step S152.

[0061] On the other hand, if the voltage of backup capacitor 16 is equal to or greater than the threshold (step S153, Yes), control unit 13 determines whether the voltage application time is equal to or less than the threshold (step S154). If the voltage application time is equal to or less than the threshold (step S154, Yes), control unit 13 causes discharge circuit 17 to discharge backup capacitor 16 (step S164), calculates the capacitance based on the discharge time (step S165), and records the capacitance (step S166). Thereafter, control unit 13 proceeds to the process of step S154.

[0062] On the other hand, if the applied voltage is not equal to or less than the threshold value in step S154 (step S154, No), the control unit 13 causes the real-time clock 19 to count the voltage application time (step S155). Next, the control unit 13 determines whether the voltage application time of the backup capacitor 16 has reached the set time (step S156). If the voltage application time of the backup capacitor 16 has not reached the set time (step S156, No), the control unit 13 proceeds to the processing of step S155.

[0063] On the other hand, if the voltage application time of the backup capacitor 16 has reached the set time (step S156, Yes), the control unit 13 causes the discharge circuit 17 to discharge the backup capacitor 16 (step S157) and calculates the capacitance based on the discharge time (step S158). Next, the control unit 13 calculates the applied voltage in accordance with the change in capacitance (step S159). Next, the control unit 13 changes the applied voltage of the backup capacitor 16 (step S160). Next, the control unit 13 determines whether the applied voltage has reached the rated voltage (step S161). If the applied voltage has not reached the rated voltage (step S161, No), the control unit 13 proceeds to the processing of step S152.

[0064] On the other hand, if the applied voltage reaches the rated voltage (step S161, Yes), the control unit 13 turns on the LED 14 (step S162). Next, the control unit 13 performs replacement processing (step S163) and proceeds to the processing of step S151.

[0065] In the above process, the backup capacitor 16 is first charged and then discharged, and the initial capacitance based on the discharge time is stored in the control unit 13. After a certain time (e.g., 1000 hours) has elapsed, the backup capacitor 16 is discharged, and the capacitance 1000 hours after the discharge time is obtained. The decrease in the current capacitance can be calculated by determining the ratio of the initial capacitance to the current capacitance. For example, if a 5% decrease in capacitance is confirmed after 1000 hours has elapsed, the decrease in capacitance can be compensated for by increasing the voltage applied to the backup capacitor 16 by 5% from the initial voltage. This allows the amount of charge stored in the backup capacitor 16 to be constant.

[0066] In this case, it is necessary to calculate the amount of charge required on the assumption that the backup capacitor 16 will be used at an applied voltage lower than its rated voltage, and to select a capacitance value accordingly. Furthermore, if the amount of charge can no longer be maintained even when the applied voltage is finally increased to the rated voltage, it can be determined that the life of the backup capacitor 16 has expired. In this case, the LED 14 attached to the control unit 13 lights up to notify the user, allowing the backup device 10 to be replaced and preventing the PC 40 from becoming unable to perform backup.

[0067] Here, the capacitance decrease is calculated from the time the voltage is applied to the backup capacitor 16. The relationship between the application time to the backup capacitor 16 and the capacitance decrease is acquired in advance and stored as a table in the control unit 13. The control unit 13 performs control according to the table. Because the relationship between the application time to the backup capacitor 16 and the capacitance decrease varies depending on the temperature, data under different temperature conditions, such as 25°C, 35°C, 45°C, and 55°C, is acquired in advance and stored as a table in the control unit 13. Note that in the process of FIG. 5, the applied voltage is increased when the application time to the backup capacitor 16 reaches 1000 hours. However, considering the relationship between the application time and the capacitance decrease described above, the applied voltage may be increased each time the capacitance decreases by 5%.

[0068] [Load information acquisition process] 11 is a diagram showing an example of a processing procedure of a load information acquisition process according to the third embodiment of the present disclosure. First, the control unit 13 acquires load information from the PC 40 (step S191). Next, the control unit 13 sets an applied voltage based on the load information (step S192). Next, the control unit 13 causes the bidirectional power supply circuit 15 to start applying a voltage to the backup capacitor 16 (step S193). Next, the control unit 13 determines whether the load information has been changed (step S194). If the load information has been changed (step S194, Yes), the control unit 13 proceeds to the processing of step S192. On the other hand, if the load information has not been changed (step S194, No), the control unit 13 proceeds to the processing of step S193.

[0069] The above processing will be explained. The load on the PC 40 that requires backup depends on whether or not an external device (such as a USB memory stick) is attached. Therefore, load information is sent from the PC 40 to the control unit 13. If the load is heavy, the voltage applied to the backup capacitor 16 is increased, and conversely, if the load is light, the voltage applied to the backup capacitor 16 is decreased. For example, if the applied voltage in the initial state is 2.3 V, if the load on the PC 40 is heavy, the applied voltage is increased to 2.3 V or higher, and if the load on the PC 40 is light, the applied voltage is decreased to 2.3 V or lower. This makes it possible to extend the life of the backup capacitor 16 while ensuring the power supply capacity required for backup.

[0070] The control unit 13 can also transmit status information of the backup device 10 (the voltage of the backup capacitor 16, the ambient temperature, and the rotation speed of the cooling fan) to the PC 40, and the information can be displayed on a monitor connected to the PC 40 as shown in FIG. 2. This allows the status of the backup device 10 to be constantly monitored. The voltage of the backup capacitor 16 can also be transmitted from the control unit 13 to a capacitor voltage level indicator such as an LED level meter, and the voltage of the backup capacitor 16 can also be monitored. The voltage information of the backup capacitor 16, temperature information, and the rotation speed of the cooling fan can also be displayed on an LCD monitor (not shown).

[0071] FIG. 12 is a diagram showing an example of a processing procedure of a charging process according to the third embodiment of the present disclosure. First, the control unit 13 causes the bidirectional power supply circuit 15 to start applying a voltage to the backup capacitor 16 (step S201). Next, the control unit 13 determines whether the voltage has reached a first set voltage (step S202). If the voltage has not reached the first set voltage (step S202, No), the control unit 13 returns to the processing of step S201. On the other hand, if the voltage has reached the first set voltage (step S202, Yes), the control unit 13 causes the bidirectional power supply circuit 15 to stop applying a voltage to the backup capacitor 16 (step S203). Next, the control unit 13 determines whether the voltage has reached a second set voltage (step S204). If the voltage has not reached the second set voltage (step S204, No), the control unit 13 waits until the voltage reaches the second set voltage (step S204). On the other hand, if the voltage reaches the second set voltage (Yes at step S204), the control unit 13 proceeds to the process at step S201.

[0072] In the above process, the voltage application is stopped when the voltage of the backup capacitor 16 reaches a predetermined first set voltage, and resumed when it reaches a predetermined second set voltage. In this case, the second set voltage is the minimum voltage required for backing up the PC 40, and the first set voltage is a voltage higher than that voltage. For example, the first set voltage can be set to 2.7 V and the second set voltage can be set to 2.5 V. When a voltage is applied to the backup capacitor 16 and reaches 2.7 V, the voltage application is stopped. When the voltage reaches 2.5 V due to natural discharge of the backup capacitor 16, the voltage application is resumed. The voltage application is stopped until the voltage drops by 0.2 V due to natural discharge of the backup capacitor 16. This extends the life of the backup capacitor 16.

[0073] The processes in FIGS. 5-12 may be performed independently, or may be performed in combination with one another or all of them.

[0074] The series of processes performed by each device described in this specification may be realized using software, hardware, or a combination of software and hardware. The programs constituting the software are stored in advance in, for example, a storage medium (non-transitory medium) provided inside or outside each device. Then, each program is loaded into RAM when executed by a computer, and executed by a processor such as a CPU.

[0075] Furthermore, the processes described herein using flowcharts and sequence diagrams do not necessarily have to be performed in the order shown. Some process steps may be performed in parallel. Furthermore, additional process steps may be employed, and some process steps may be omitted.

[0076] (effect) The backup device includes a backup capacitor 16 consisting of a supercapacitor that stores electrical energy for backup, a bidirectional power supply circuit 15 that charges the backup capacitor with power from a power supply line and supplies power to the power supply line with the power discharged from the backup capacitor 16, and a control unit 13 that controls the charging and discharging of the backup capacitor 16 in the bidirectional power supply circuit 15 according to the voltage of the power supply line, and the control unit 13 controls to adjust the applied voltage when charging the backup capacitor 16 according to the power consumption of a device connected to the power supply line. This makes it possible to reduce the decrease in capacitance of the backup capacitor 16.

[0077] Furthermore, the control unit 13 further performs control to adjust the applied voltage in accordance with the voltage application time when charging the backup capacitor 16. This makes it possible to reduce the decrease in the capacitance of the backup capacitor 16.

[0078] The device further includes a discharge circuit 17 that discharges the backup capacitor 16, and the control unit 13 further predicts the life of the backup capacitor 16 based on the discharge time when the discharge circuit 17 discharges the backup capacitor 16. This makes it possible to detect when the backup capacitor 16 needs to be replaced.

[0079] The device further includes a cooling unit 50 that cools the backup capacitor 16, and the control unit 13 further controls the cooling unit based on the temperature of the backup capacitor 16. This makes it possible to reduce a decrease in the capacitance of the backup capacitor 16.

[0080] The device further includes a display unit 20 that displays information about the backup capacitor 16, and the control unit 13 further controls the display unit 20 to display the information about the backup capacitor 16. This improves convenience.

[0081] A control method for a backup device includes a backup device 10 having a backup capacitor 16 made of a supercapacitor that stores electrical energy for backup, and a bidirectional power supply circuit 15 that charges the backup capacitor with power from a power supply line and supplies power to the power supply line with the power discharged from the backup capacitor 16, the method including controlling the charging and discharging of the backup capacitor 16 in accordance with the power consumption of a device connected to the power supply line, and adjusting the applied voltage when charging the backup capacitor 16 in accordance with the power consumption of the device connected to the power supply line. This makes it possible to reduce the decrease in capacitance of the backup capacitor 16.

[0082] The computer system includes a computer connected to a power supply line, a backup capacitor 16 consisting of a supercapacitor for storing electrical energy for backup, a bidirectional power supply circuit 15 for charging the backup capacitor 16 with power from the power supply line and supplying power to the power supply line with the power discharged from the backup capacitor 16, and a control unit 13 for controlling the charging and discharging of the backup capacitor 16 in the bidirectional power supply circuit 15 according to the voltage of the power supply line, the control unit 13 being a system for controlling the voltage applied when charging the backup capacitor 16 according to the power consumption of the computer. This makes it possible to reduce the decrease in capacitance of the backup capacitor 16.

[0083] The effects described in this specification are merely examples and are not limiting, and other effects may also be present. [Explanation of symbols]

[0084] 10 Backup Device 13 Control Unit 15 Bidirectional power circuit 16 Backup capacitor 17 Discharge circuit 18 Temperature Sensor 20 Display section 30 power supply 40 PC 50 Cooling section

Claims

1. a backup capacitor including a supercapacitor for storing electrical energy for backup; a bidirectional power supply circuit that charges the backup capacitor with power from a power supply line and supplies power to the power supply line with power generated by discharging the backup capacitor; a control unit that controls charging and discharging of the backup capacitor in the bidirectional power supply circuit in accordance with the voltage of the power supply line; Equipped with The control unit controls the voltage applied when charging the backup capacitor in accordance with the power consumption of a device connected to the power supply line. Backup device.

2. 2. The backup device according to claim 1, wherein the control unit further performs control to adjust the applied voltage depending on the voltage application time when charging the backup capacitor.

3. a discharge circuit for discharging the backup capacitor; The control unit further predicts a life of the backup capacitor based on a discharge time when the discharge circuit discharges the backup capacitor.

3. The backup device according to claim 1.

4. a cooling unit that cools the backup capacitor; 3. The backup device according to claim 1, wherein the control unit further controls the cooling unit based on the temperature of the backup capacitor.

5. Further, a display unit is provided to display information about the backup capacitor, The control unit further controls the display unit to display information about the backup capacitor.

3. The backup device according to claim 1.

6. A backup device comprising: a backup capacitor formed of a supercapacitor for storing electrical energy for backup; and a bidirectional power supply circuit for charging the backup capacitor with power from a power supply line and supplying power to the power supply line with power discharged from the backup capacitor, controlling charging and discharging of the backup capacitor in accordance with power consumption of a device connected to the power supply line; adjusting the voltage applied when charging the backup capacitor in accordance with the power consumption of the device connected to the power supply line; A method for controlling a backup device including:

7. a computer connected to a power supply line; a backup capacitor including a supercapacitor for storing electrical energy for backup; a bidirectional power supply circuit that charges the backup capacitor with power from the power supply line and supplies power to the power supply line with power generated by discharging the backup capacitor; a control unit that controls charging and discharging of the backup capacitor in the bidirectional power supply circuit in accordance with the voltage of the power supply line; Equipped with The control unit controls the voltage applied when charging the backup capacitor in accordance with the power consumption of the computer. Computer system.

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