Uninterruptible power supply device

Abstract

The uninterruptible power supply device has a normal mode in which power supplied from an AC power supply is supplied to a load, a standby mode in which power stored in a battery is supplied to the load when the AC power supply is powered off, and a deterioration diagnosis mode in which the deterioration state of the battery is diagnosed. A control device of an uninterruptible power supply device periodically shifts to a deterioration diagnosis mode during execution of a normal mode. In the execution of the deterioration diagnosis mode, the control device stops the charging of the storage battery by stopping the operation of the power converter. The control device measures the voltage (VB) of the storage battery at a first timing (t2) at which a first time (T1) has elapsed since stopping the charging of the storage battery, and diagnoses the deterioration state of the storage battery on the basis of the measured value (VB1) of the voltage of the storage battery at the first timing.

Description

Technical Field

[0001] The present disclosure relates to an uninterruptible power supply device, and more particularly, to a technology for diagnosing degradation of a storage battery used in the uninterruptible power supply device. Background Art

[0002] For example, Japanese Patent Publication No. 2008-259296 (Patent Document 1) discloses an uninterruptible power supply device having an uninterruptible power supply device body, a plurality of storage batteries, and an automatic storage battery degradation diagnosis unit. The uninterruptible power supply device body has a converter that converts input power from an AC power supply into DC power, and an inverter that converts the DC power output from the converter into AC power and outputs it to a load. A plurality of storage batteries are connected in series with the DC power section between the converter and the inverter, and supply power to the load when the AC power supply is abnormal. The automatic storage battery degradation diagnosis unit performs a test discharge on the plurality of storage batteries during the operation of the uninterruptible power supply device to detect abnormalities of the plurality of storage batteries as a whole.

[0003] In the above configuration, during the test discharge of the plurality of storage batteries, the floating charge voltage of the storage batteries gradually decreases. However, as the degradation of the storage batteries progresses, the decrease in the floating charge voltage during discharge becomes significant. When the floating charge voltage decreases to the abnormality determination voltage during the test discharge, the automatic storage battery degradation diagnosis unit determines that the plurality of storage batteries as a whole are abnormal.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2008-259296 Summary of the invention

[0007] Problems to be solved by the invention

[0008] The uninterruptible power supply device described in Patent Document 1 supplies power to a load while diagnosing the degradation state of the batteries by test-discharging a plurality of batteries through an automatic battery degradation diagnosis unit when power is normally supplied from an AC power supply. Thus, during the test discharge, input power from the AC power supply is supplied to the load via the uninterruptible power supply device body, and power discharged from a plurality of batteries is supplied to the load. Therefore, when the uninterruptible power supply device is operated at a light load, the current output from the uninterruptible power supply device to the load becomes smaller, making it difficult to pass a constant current for test discharge through the plurality of batteries. As a result, when the load current is small and the load is light, there is a concern that the automatic battery degradation unit cannot diagnose the degradation state of the plurality of batteries.

[0009] Furthermore, in order to improve the reliability of power supply of the uninterruptible power supply device when an AC power source is abnormal, it is required to be able to diagnose the deterioration state of the storage battery with higher accuracy.

[0010] The present disclosure has been made in view of the above-mentioned problems, and an object of the present disclosure is to provide an uninterruptible power supply device capable of diagnosing the degradation state of a storage battery with high accuracy regardless of the size of a load.

[0011] Means for solving problems

[0012] The uninterruptible power supply device disclosed in the present invention has: a normal mode in which the power supplied from the AC power supply is supplied to the load; a backup mode in which the power stored in the battery is supplied to the load when the AC power supply fails; and a degradation diagnosis mode in which the degradation state of the battery is diagnosed. The uninterruptible power supply device includes a power converter and a control device. The power converter uses the power supplied from the AC power supply to float charge the battery in the normal mode, and discharges the battery in the backup mode. The control device periodically transfers to the degradation diagnosis mode during the execution of the normal mode. During the execution of the degradation diagnosis mode, the control device stops charging the battery by stopping the operation of the power converter. The control device measures the voltage of the battery at a first timing after a first time has passed since the charging of the battery was stopped, and diagnoses the degradation state of the battery based on the measured value of the voltage of the battery at the first timing.

[0013] Effects of the Invention

[0014] According to the present disclosure, it is possible to provide an uninterruptible power supply device capable of diagnosing the degradation state of a storage battery with high accuracy regardless of the magnitude of a load. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a circuit block diagram showing the configuration of the uninterruptible power supply device according to the first embodiment.

[0016] Figure 2 This is a block diagram showing an example of the hardware configuration of the control device.

[0017] Figure 3 A block diagram showing the main parts of the control device.

[0018] Figure 4 The following is a diagram for explaining the operation modes of the uninterruptible power supply device.

[0019] Figure 5 This is a block diagram showing a portion of the control circuit related to control of a converter, an inverter, and a bidirectional chopper.

[0020] Figure 6 It is a diagram for explaining the degradation diagnosis process of the battery in the degradation diagnosis unit.

[0021] Figure 7 This is a graph showing an example of the relationship between battery usage time and DC resistance.

[0022] Figure 8 This is a flowchart showing the flow of the battery degradation diagnosis process according to the first embodiment.

[0023] Fig. 9 This is a diagram for explaining the degradation diagnosis process in the degradation diagnosis unit according to the second embodiment.

[0024] Fig.10 This is a flowchart showing the flow of battery degradation diagnosis processing according to the second embodiment.

[0025] Fig.11 This is a flowchart showing the flow of battery degradation diagnosis processing in the third embodiment.

[0026] Fig.12 This is a flowchart showing the flow of battery degradation diagnosis processing in the third embodiment.

[0027] Fig.13 This is a circuit block diagram showing the configuration of an uninterruptible power supply device according to a fourth embodiment. DETAILED DESCRIPTION

[0028] The embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In addition, the same reference numerals are attached to the same or corresponding parts in the drawings, and their description will not be repeated.

[0029] [Implementation Method 1]

[0030] <Uninterruptible power supply unit configuration>

[0031] Figure 1 This is a circuit block diagram showing the configuration of the uninterruptible power supply device according to the first embodiment.

[0032] like Figure 1 As shown, the uninterruptible power supply device 100 of the first embodiment includes an input terminal 1, a DC terminal 2, an output terminal 3, switches S1 to S3, a converter 4, current detectors CD1 to CD3, a DC line 5, a capacitor 6, a bidirectional chopper 7, an inverter 8, an operation unit 9, and a control device 10. In addition, the uninterruptible power supply device 100 supplies three-phase AC power to a load 13, but in order to simplify the drawings and descriptions, Figure 1 Only the part related to one phase is shown.

[0033] The input terminal 1 receives AC power of a predetermined frequency (for example, a commercial frequency) from an AC power source 11. The AC power source 11 may be a commercial AC power source or a generator.

[0034] The DC terminal 2 is connected to a battery 12. The battery 12 stores DC power. The battery 12 is, for example, a secondary battery such as a lithium ion battery or a lead storage battery. The battery 12 corresponds to an example of a "storage battery".

[0035] Output terminal 3 is connected to load 13. Load 13 is driven by AC power of a predetermined frequency (for example, a commercial frequency) supplied from uninterruptible power supply device 100.

[0036] The switch S1 is connected between the input terminal 1 and the AC node of the converter 4, and is controlled by the control device 10. When the AC power is properly supplied from the AC power source 11 (when the AC power source 11 is healthy), the switch S1 is turned on, and the AC power is supplied from the AC power source 11 to the converter 4 via the switch S1. When the AC power is not normally supplied from the AC power source 11 (when the AC power source 11 is powered off), the switch S1 is turned off, and the connection between the AC power source 11 and the converter 4 is cut off.

[0037] The instantaneous value of the AC input voltage VI supplied from the AC power source 11 is detected by the control device 10. Based on the instantaneous value of the AC input voltage VI, the control device 10 determines whether the AC voltage is normally supplied from the AC power source 11. The current detector CD1 detects the AC input current Ii flowing between the AC power source 11 and the converter 4, and provides the control device 10 with a signal Iif indicating the detection value.

[0038] The converter 4 is controlled by the control device 10, and when the AC power source 11 is healthy, it converts the AC power from the AC power source 11 into DC power and outputs it to the DC line 5. The converter 4 is a well-known converter including a plurality of sets of IGBTs (Insulated Gate Bipolar Transistors) and diodes.

[0039] The capacitor 6 is connected to the DC line 5 to smooth and stabilize the DC voltage VD of the DC line 5. The instantaneous value of the DC voltage VD of the DC line 5 is detected by the control device 10.

[0040] When the AC power source 11 is healthy, the control device 10 controls the converter 4 so that the DC voltage VD of the DC line 5 becomes the reference DC voltage VDR. When the AC power source 11 fails, the control device 10 stops the operation of the converter 4.

[0041] The DC line 5 is connected to the DC terminal 2 via the bidirectional chopper 7 and the switch S2. The switch S2 is controlled by the control device 10. When the uninterruptible power supply device 100 is used, the switch S2 is turned on. When the battery 12 and the bidirectional chopper 7 are maintained, the switch S2 is turned off.

[0042] The instantaneous value of the voltage between the terminals of the battery 12 (hereinafter also referred to as "battery voltage") VB is detected by the control device 10. The current detector CD2 detects the DC current IB flowing between the battery 12 and the bidirectional chopper 7, and provides the control device 10 with a signal IBf indicating the detected value.

[0043] The bidirectional chopper 7 is controlled by the control device 10, and transmits and receives DC power between the DC line 5 and the battery 12. The bidirectional chopper 7 is a well-known chopper including a plurality of IGBTs, diodes, and reactors.

[0044] When the AC power source 11 is healthy, the control device 10 controls the bidirectional chopper 7 so that the battery voltage VB becomes the reference DC voltage VBR. When the AC power source 11 is out of power, the control device 10 controls the bidirectional chopper 7 so that the DC voltage VD of the DC line 5 becomes the reference DC voltage VDR. The bidirectional chopper 7 corresponds to an embodiment of the "power converter".

[0045] In addition, the DC line 5 is connected to the DC node of the inverter 8, and the AC node of the inverter 8 is connected to the output terminal 3 via the switch S3. The switch S3 is controlled by the control device 10. When the uninterruptible power supply device 100 is used, the switch S3 is turned on. When the inverter 8 is maintained, the switch S3 is turned off.

[0046] The current detector CD3 detects the AC output current Io of the inverter 8 and provides a signal Iof indicating the detected value to the control device 10. The AC output current Io corresponds to the load current flowing from the uninterruptible power supply device 100 to the load 13. In addition, the instantaneous value of the AC output voltage VO applied to the load 13 is detected by the control device 10.

[0047] Inverter 8 is controlled by control device 10, converts DC power supplied from converter 4 and bidirectional chopper 7 via DC line 5 into AC power of a predetermined frequency (for example, commercial frequency), and supplies the AC power to load 13. Inverter 8 is a well-known inverter including a plurality of IGBTs and diodes.

[0048] When AC power source 11 is healthy, inverter 8 converts DC power supplied from converter 4 or bidirectional chopper 7 into AC power and supplies it to load 13. At this time, control device 10 controls inverter 8 so that AC output voltage VO becomes a sinusoidal reference AC voltage VOR.

[0049] The operation unit 9 includes a plurality of buttons, a plurality of switches, and an image display unit. The user of the uninterruptible power supply device 100 can turn on and off the power supply of the uninterruptible power supply device 100, or automatically or manually operate the uninterruptible power supply device 100 by operating the operation unit 9. The operation unit 9 outputs signals and information indicating the contents of the operation by the user to the control device 10.

[0050] The control device 10 controls the switches S1 to S3, the converter 4, the bidirectional chopper 7, and the inverter 8 based on the signal from the operation unit 9, the AC input voltage VI, the AC output voltage VO, the DC voltage VD, the battery voltage VB, the AC input current Ii, the battery current IB, and the AC output current Io.

[0051] <Hardware Configuration of Control Device>

[0052] Figure 2 2 is a block diagram showing an example of the hardware configuration of the control device 10. Typically, the control device 10 can be configured by a microcomputer in which a predetermined program is stored in advance.

[0053] exist Figure 2 In the example of FIG. 1 , the control device 10 includes a CPU (Central Processing Unit) 102, a memory 104, and an input / output (I / O) circuit 106. The CPU 102, the memory 104, and the I / O circuit 106 can mutually transmit and receive data via a bus 108. A program is stored in a part of the memory 104, and the CPU 102 executes the program to realize various functions described later. The I / O circuit 106 inputs and outputs signals and data to and from the outside of the control device 10.

[0054] Or, with Figure 2 Different from the example of FIG. 1 , at least a part of the control device 10 can be formed using a circuit such as an FPGA (Field Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit). In addition, at least a part of the control device 10 can also be formed by an analog circuit.

[0055] <Functional Configuration of Control Device>

[0056] Figure 3 is a block diagram showing the main parts of the control device 10. Figure 3 As shown, the control device 10 includes voltage detectors 21 to 24 , a power failure detector 25 , a timer 26 , an output unit 27 , and a control circuit 28 .

[0057] The voltage detector 21 detects the instantaneous value of the AC input voltage VI supplied from the AC power supply 11, and outputs a signal VIf indicating the detected value to the power failure detector 25 and the control circuit 28. The voltage detector 22 detects the instantaneous value of the AC output voltage VO applied to the load 13, and outputs a signal VOf indicating the detected value to the control circuit 28.

[0058] The voltage detector 23 detects the instantaneous value of the DC voltage VD of the DC line 5, and outputs a signal VDf indicating the detected value to the control circuit 28. The voltage detector 24 detects the instantaneous value of the battery voltage VB, and outputs a signal VBf indicating the detected value to the control circuit 28. Figure 1 )'s output signals Iif, IBf, Iof are provided to the control circuit 28.

[0059] The power failure detector 25 detects whether a power failure occurs in the AC power source 11 based on the output signal VIf of the voltage detector 21, and generates a power failure detection signal indicating the detection result. Output to the control circuit 28. When the AC power supply 11 is sound, the power failure detection signal When a power failure occurs in the AC power source 11, the power failure detection signal The "L" level is set to the active level.

[0060] For example, when the AC input voltage VI is higher than the lower limit value, the power failure detector 25 determines that the AC power supply 11 is healthy and sends a power failure detection signal In addition, when the AC input voltage VI is lower than the lower limit value, the power failure detector 25 determines that a power failure of the AC power source 11 has occurred, and sets the power failure detection signal Set to the "L" level for the activation level.

[0061] Timer 26 is reset when reset signal RST from control circuit 28 becomes active level “H” level for a predetermined time, measures time TD elapsed from reset, and outputs signal TDf indicating measured time TD to control circuit 28 .

[0062] The control circuit 28 is based on the output signals VIf, VOf, VDf, and VBf of the voltage detectors 21 to 24, the output signals Iif, IBf, and Iof of the current detectors CD1 to CD3, and the signal The entire uninterruptible power supply device 100 is controlled based on the signal from the operation unit 9 .

[0063] In addition, when the AC power source 11 is healthy, the control circuit 28 supplies AC power to the load 13 while periodically diagnosing the degradation state of the battery 12. Based on the diagnosis result, the control circuit 28 outputs a status signal indicating the degradation state of the battery 12. Output to output section 27. In the state signal The information related to the direct current resistance (DCR) of the battery 12 obtained by the degradation diagnosis can be included.

[0064] In addition, the control circuit 28 determines whether the battery 12 is deteriorated based on the diagnosis result, and sends a degradation detection signal indicating the determination result. The degradation detection signal is output to the output unit 27. When it is determined that the battery 12 is not degraded, the degradation detection signal When it is determined that the battery 12 is degraded, the degradation detection signal The "H" level is set to an active level. The deterioration diagnosis of the battery 12 will be described later.

[0065] The output unit 27 is based on the status signal An image or the like indicating the degradation state of the battery 12 is presented to the user of the uninterruptible power supply 100. When the activation level is set to "H" level, output unit 27 notifies the user of uninterruptible power supply 100 of the deterioration of battery 12 by using sound, light, image, etc. Output unit 27 can use the image display unit of operation unit 9.

[0066] Alternatively, output unit 27 may be an external device (eg, a server) that is communicatively connected to uninterruptible power supply 100. The external device is configured to receive a status signal from uninterruptible power supply 100 via a communication network such as the Internet. and degradation detection signal Based on the received signal, the user is presented with information on the degradation state of battery 12. Thus, the user of uninterruptible power supply device 100 can monitor the degradation state of battery 12 remotely.

[0067] <Uninterruptible power supply operation mode>

[0068] Figure 4 1 is a diagram for explaining the operation mode of the uninterruptible power supply device 100. Figure 4 As shown, the uninterruptible power supply device 100 has a normal mode, a standby mode, and a degradation diagnosis mode. The control circuit 28 controls the power failure detection signal The output signal TDf of the timer 26 and the reset signal RST selectively execute the normal mode, the standby mode, and the degradation diagnosis mode.

[0069] (Normal mode)

[0070] When the AC power supply is 11 The control circuit 28 executes the normal mode. In the normal mode, the control circuit 28 turns on the switches S1 to S3. In addition, the control circuit 28 controls the converter 4 based on the signals VIf, VDf, and Iif so that the DC voltage VD of the DC line 5 becomes the reference DC voltage VDR. Furthermore, the control circuit 28 controls the bidirectional chopper 7 based on the signals VBf and Ibf so that the battery voltage VB becomes the reference DC voltage VBR.

[0071] In addition, the control circuit 28 controls the inverter 8 based on the signals VOf and Iof so that the AC output voltage VO of the inverter 8 becomes the sinusoidal reference AC voltage VOR. In this case, the load current is supplied from the inverter 8 to the load 13, and the load 13 operates.

[0072] (Backup Mode)

[0073] When a power outage occurs in the AC power source 11 The control circuit 28 executes the standby mode. In the standby mode, the control circuit 28 turns off the switch S1 to stop the operation of the converter 4. In addition, the control circuit 28 controls the bidirectional chopper 7 based on the signals VBf and Ibf so that the DC voltage VD of the DC line 5 becomes the reference DC voltage VDR. Furthermore, the control circuit 28 controls the inverter 8 based on the signals VOf and Iof so that the AC output voltage VO of the inverter 8 becomes the sinusoidal reference AC voltage VOR. Therefore, even if a power outage of the AC power source 11 occurs, the operation of the load 13 can be continued while the DC power is stored in the battery 12.

[0074] When the AC power supply 11 recovers from the power failure state and becomes healthy The control circuit 28 shifts from the standby mode to the normal mode. The control circuit 28 turns on the switch S1 to start the operation of the converter 4, controls the converter 4 so that the DC voltage VD of the DC line 5 becomes the reference DC voltage VD, and controls the bidirectional chopper 7 so that the battery voltage VB becomes the reference DC voltage VBR. In addition, the control circuit 28 controls the inverter 8 so that the AC output voltage VO of the inverter 8 becomes the sinusoidal reference AC voltage VOR.

[0075] (Deterioration diagnosis mode)

[0076] When the time TD indicated by the output signal TDf of the timer 26 exceeds the predetermined time Tc during the execution of the normal mode, the control circuit 28 executes the degradation diagnosis mode. The predetermined time Tc is a cycle for executing the degradation diagnosis mode during the execution of the normal mode.

[0077] In the degradation diagnosis mode, the control circuit 28 controls the converter 4 based on the signals VIf, VDf, and Iif so that the DC voltage VD of the DC line 5 becomes the reference DC voltage VDR. In addition, the control circuit 28 controls the inverter 8 based on the signals VOf and Iof so that the AC output voltage VO of the inverter 8 becomes the sinusoidal reference AC voltage VOR.

[0078] Then, while the inverter 8 supplies AC power to the load 13, the control circuit 28 diagnoses the degradation state of the battery 12. At this time, the control circuit 28 controls the operation of the bidirectional chopper 7 based on the output signal TDf of the timer 26. The control of the bidirectional chopper 7 will be described later. The control circuit 28 diagnoses the degradation state of the battery 12 based on the battery voltage VB represented by the signal VBf, and outputs the status signal indicating the degradation state. The control circuit 28 determines whether the battery 12 is degraded based on the battery voltage VB. If the control circuit 28 determines that the battery 12 is degraded, the degradation detection signal When it is determined that the battery 12 is not degraded, the control circuit 28 sets the degradation detection signal Set to the "L" level, which is the inactive level.

[0079] When the execution of the degradation diagnosis mode is completed, control circuit 28 causes reset signal RST to be at an active “H” level for a predetermined time to reset timer 26 and execute the normal mode again.

[0080] In addition, when a power failure of the AC power supply 11 occurs during the execution of the degradation diagnosis mode, The control circuit 28 executes the standby mode. At this time, the control circuit 28 stops the operation of the converter 4 and controls the bidirectional chopper 7 so that the DC voltage VD of the DC line 5 becomes the reference DC voltage VDR. In response to the interruption of the execution of the degradation diagnosis mode, the control circuit 28 makes the reset signal RST become the "H" level of the active level for a predetermined time, and resets the timer 26.

[0081] <Functional Configuration of Control Circuit>

[0082] Figure 5 2 is a block diagram showing a portion of the control circuit 28 related to the control of the converter 4, the inverter 8, and the bidirectional chopper 7. Figure 5As shown, the control circuit 28 includes a mode setting unit 30 , a command generating unit 32 , a power supply control unit 34 , a charge and discharge control unit 36 ​​, a degradation diagnosis unit 38 , a storage unit 40 , and a threshold generating unit 42 .

[0083] The mode setting unit 30 is based on the output signal of the power failure detector 25. Output signal TDf of timer 26 and reset signal RST supplied from degradation diagnosis unit 38 set the operation mode of uninterruptible power supply device 100 .

[0084] Specifically, the power failure detection signal When the power failure detection signal TD is at the "H" level and the measured time TD of the timer 26 is less than the predetermined time Tc, the mode setting unit 30 sets the operation mode to the normal mode. When the power failure detection signal TD is at the "H" level and the measured time TD of the timer 26 exceeds the predetermined time Tc, the mode setting unit 30 sets the operation mode to the degradation diagnosis mode. When the level is "L", the mode setting unit 30 sets the operation mode to the standby mode. The mode setting unit 30 sends a signal indicating the set operation mode to the Output to the power supply control unit 34 and the command generation unit 32 .

[0085] The power supply control unit 34 controls the power supply based on the output signal of the mode setting unit 30. The converter 4 and the inverter 8 are controlled by the output signals VIf, VDf, and VOf of the voltage detectors 21 to 23 and the output signals Iif and Iof of the current detectors CD1 and CD2 .

[0086] Specifically, in the signal When the operation mode shown is the normal mode or the degradation diagnosis mode, the power supply control unit 34 controls the converter 4 based on the signals VIf, VDf, and Iif so that the DC voltage VD of the DC line 5 becomes the reference DC voltage VDR. In addition, the power supply control unit 34 controls the inverter 8 based on the signals VOf and Iof so that the AC output voltage VO of the inverter 8 becomes the sinusoidal reference AC voltage VOR.

[0087] In the signal When the operation mode shown is the standby mode, the power supply control unit 34 stops the operation of the converter 4 and controls the inverter 8 based on the signals VOf and Iof so that the AC output voltage VO of the inverter 8 becomes the sinusoidal reference AC voltage VOR.

[0088] The command generation unit 32 generates a command based on the output signal of the mode setting unit 30. The output signal TDf of the timer 26 generates a charge command for instructing the execution / stop of charging the battery 12 and a discharge command for instructing the execution / stop of discharging the battery 12. When instructing the execution of charging the battery 12, the charge command is set to the "H" level of the active level, and when instructing the stop of charging, the charge command is set to the "L" level of the inactive level. When instructing the execution of discharging the battery 12, the discharge command is set to the "H" level of the active level, and when instructing the stop of discharging, the discharge command is set to the "L" level of the inactive level.

[0089] In the signal When the operation mode shown is the normal mode, the charge command is set to the "H" level and the discharge command is set to the "L" level. When the operation mode shown is the standby mode, the charge command is set to the "L" level, and the discharge command is set to the "H" level.

[0090] In the signal When the operation mode shown is the degradation diagnosis mode, the charge command is set to the "L" level and the discharge command is set to the "L" level. However, during the execution of the degradation diagnosis mode, the discharge command is set to the "H" level for a predetermined time T2 based on the output signal TDf of the timer 26. The command generation unit 32 sends the signal indicating the generated charge command and discharge command to the "H" level. The signal is output to the charge and discharge control unit 36 ​​and the degradation diagnosis unit 38 .

[0091] The charge and discharge control unit 36 ​​generates a charge and discharge signal based on the output signal of the command generation unit 32. The bidirectional chopper 7 is controlled by the output signals VDf and VBf of the voltage detectors 23 and 24 and the output signal IBf of the current detector CD2 .

[0092] Specifically, in the signal When the charge command is at the "H" level and the discharge command is at the "L" level, the charge and discharge control unit 36 ​​controls the bidirectional chopper 7 so that the battery voltage VB becomes the reference DC voltage VBR. When the charge command is at the "L" level and the discharge command is at the "H" level, the charge and discharge control unit 36 ​​controls the bidirectional chopper 7 so that the DC voltage VD of the DC line 5 becomes the reference DC voltage VDR. When both the charging command and the discharging command shown are at “L” level, the charging and discharging control unit 36 ​​stops the operation of the bidirectional chopper 7 .

[0093] The degradation diagnosis unit 38 generates a signal based on the output signal of the command generation unit 32. The deterioration state of the battery 12 is diagnosed using the output signal TDf of the timer 26 and the output signal VBf of the voltage detector 24 .

[0094] <Battery Deterioration Diagnosis Processing>

[0095] Figure 6 2 is a diagram for explaining the degradation diagnosis process of the battery 12 in the degradation diagnosis unit 38. Figure 6 2 shows the waveform of the battery voltage VB indicated by the output signal VBf of the voltage detector 24 and the waveforms of the charging command and the discharging command generated by the command generating unit 32 .

[0096] Reference Figure 6 At time t1, when the measured time TD of timer 26 exceeds the predetermined time Tc, uninterruptible power supply device 100 shifts from the normal mode to the degradation diagnosis mode.

[0097] In the execution of the normal mode before time t1, the charge command is set to the "H" level and the discharge command is set to the "L" level. In response to the "H" level charge command, the charge and discharge control unit 36 ​​controls the bidirectional chopper 7 so that the battery voltage VB becomes the reference DC voltage VBR. As a result, the battery 12 is float charged, and the battery voltage VB at time t1 is equal to the reference DC voltage VBR.

[0098] In response to the transition to the degradation diagnosis mode at time t1 , the charge command is set to “L” level. In response to the “L” level charge command, the charge and discharge control unit 36 ​​stops the operation of the bidirectional chopper 7 , thereby stopping the charging of the battery 12 .

[0099] By stopping the charging of the battery 12, the battery voltage VB gradually decreases after time t1. The decrease in the battery voltage VB is caused by the internal resistance of the battery 12. In detail, the battery voltage VB drops sharply immediately after the charging is stopped. This voltage drop is caused by the voltage drop (IR drop) caused by the current during charging and the internal resistance of the battery 12. In addition, after the voltage drop caused by the IR drop, the battery voltage VB also gradually decreases. Such behavior of the battery voltage VB after charging is stopped is also called relaxation characteristics or transition characteristics.

[0100] In addition, the IR drop is mainly caused by the ohmic component contained in the internal resistance of the battery 12. The slow voltage drop after the IR drop is caused by components other than the ohmic component contained in the internal resistance of the battery 12 (hereinafter also referred to as "relaxation components"). Through this relaxation component, the battery voltage VB slowly decreases, for example, from 30 minutes to 1 hour after charging is stopped. The battery voltage VB eventually converges to a voltage value corresponding to the battery capacity. The time from stopping the charging of the battery 12 to the convergence of the battery voltage VB varies depending on the battery.

[0101] As the degradation of the battery 12 progresses, the internal resistance of the battery 12 gradually increases. In particular, the relaxation component of the internal resistance increases with degradation. In addition, as the degradation of the battery 12 progresses, the voltage and battery capacity decrease. Therefore, as the degradation of the battery 12 progresses, the amount of drop in the battery voltage VB after charging is stopped becomes larger.

[0102] The degradation diagnosis unit 38 measures the battery voltage VB at time t2 after a predetermined time T1 has passed since time t1 when charging of the battery 12 is stopped, based on the output signal VBf of the voltage detector 24. In the following description, the measured value of the battery voltage VB at time t2 is expressed as "battery voltage VB1". The predetermined time T1 is set to, for example, about 30 minutes to 1 hour. The predetermined time T1 is set to include the time for the battery voltage VB to relax after charging of the battery 12 is stopped. In this way, the influence of the relaxation of the battery voltage VB after charging is stopped can be reduced, and the capacity degradation of the battery 12 can be diagnosed.

[0103] The degradation diagnosis unit 38 determines whether the battery 12 is degraded based on the battery voltage VB1. Specifically, the degradation diagnosis unit 38 compares the battery voltage VB1 with a predetermined threshold voltage Vth, and generates a degradation detection signal based on the comparison result. When VB1 ≥ Vth, it is determined that the battery 12 is not degraded, and the degradation detection signal When VB1<Vth, it is determined that the battery 12 is deteriorated, and the degradation detection signal is set to “H” level.

[0104] Next, during a predetermined time T2 from time t3 after time t2 to time t4, the discharge command is temporarily set to the "H" level. The predetermined time T2 is set to, for example, about several tens of milliseconds to one second.

[0105] The charge and discharge control unit 36 ​​operates the bidirectional chopper 7 in response to the discharge command of the "H" level, thereby performing pulse discharge of the battery 12. The charge and discharge control unit 36 ​​controls the bidirectional chopper 7 so that the DC voltage VD of the DC line 5 becomes the reference DC voltage VDR at a predetermined time T2. During the execution of the pulse discharge, the battery 12 is discharged at a constant current value.

[0106] During the execution of pulse discharge, the battery voltage VB decreases. Specifically, immediately after the start of pulse discharge, the battery voltage VB decreases sharply due to the internal resistance of the battery 12, and then gradually decreases. The degradation diagnosis unit 38 measures the minimum voltage of the battery 12 during the execution of pulse discharge based on the output signal VBf of the voltage detector 24. In the following description, the measured value of the minimum voltage during the execution of pulse discharge is expressed as "battery voltage VB2". The battery voltage VB2 is equivalent to the battery voltage VB at the time t4 when the pulse discharge is stopped.

[0107] By stopping the pulse discharge at time t4, the battery voltage VB starts to rise. Immediately after the pulse discharge is stopped, the battery voltage VB rises sharply. This voltage rise is caused by the current during discharge and the internal resistance of the battery 12.

[0108] The degradation diagnosis unit 38 measures the battery voltage VB at time t5 after a predetermined time T3 has passed since the time t4 when the pulse discharge is stopped, based on the output signal VBf of the voltage detector 24. The predetermined time T3 is set to, for example, several tens of milliseconds to about one second. In the following description, the measured value of the battery voltage VB at time t5 is expressed as "battery voltage VB3".

[0109] Next, the degradation diagnosis unit 38 calculates the direct current resistance (DCR) of the battery 12 using the battery voltage VB2, which is the minimum voltage during the pulse discharge, the battery voltage VB3 immediately after the pulse discharge, and the current value I during the pulse discharge. The DCR is calculated by the following equation (1). The DCR includes the above-mentioned ohmic component and relaxation component.

[0110] DCR=(VB3-VB2) / I···(1)

[0111] The degradation diagnosis unit 38 determines the degradation state of the battery 12 based on the calculated DCR. In one aspect, the degradation diagnosis unit 38 determines the progress of the degradation of the battery 12 by comparing the DCR calculated in the past degradation diagnosis mode with the DCR calculated in the current degradation diagnosis mode. For example, when the increase in DCR since the last degradation diagnosis mode is greater than the increase in DCR in the past, it can be determined that the rate of progression of the degradation of the battery 12 is on an upward trend. In this case, the life of the battery 12 is expected to be shorter than expected. On the contrary, when it is determined based on the increase in DCR that the rate of progression of the degradation of the battery 12 is slow, the life of the battery 12 is expected to be longer than expected. The degradation diagnosis unit 38 generates a status signal based on these judgment results.

[0112] Furthermore, the degradation diagnosis unit 38 determines whether the battery 12 has degraded based on the calculated DCR. Specifically, the degradation diagnosis unit 38 compares the calculated DCR with the threshold value DCRth supplied from the threshold value generating unit 42, and generates a degradation detection signal based on the comparison result. When DCR≦DCRth, it is determined that the battery 12 is not degraded, and the degradation detection signal When DCR>DCRth, it is determined that the battery 12 is degraded, and the degradation detection signal is set to “H” level.

[0113] When the execution of the degradation diagnosis mode ends (time t6), degradation diagnosis unit 38 sets reset signal RST to the "H" level for a predetermined time to reset timer 26 and execute the normal mode again. As a result, the charge command is set to the "H" level.

[0114] return Figure 5 The degradation diagnosis unit 38 generates the state signal and degradation detection signal The output is output to the output unit 27. The output unit 27 is based on the state signal Information on the degradation state of the battery 12 is presented to the user of the uninterruptible power supply 100. For example, the output unit 27 generates a graph showing the time transition of the calculated value of the DCR (see Figure 7 ) and displayed on the image display unit of the operation unit 9 (or the display of an external device). When at the "H" level, output unit 27 notifies the user of uninterruptible power supply 100 that battery 12 is deteriorating by using sound, light, images, or the like.

[0115] Furthermore, degradation diagnosis unit 38 stores the calculated DCR in storage unit 40. Storage unit 40 stores the usage time of battery 12 and the calculated value of DCR in association with each other. Figure 7 This is a diagram showing an example of the relationship between the usage time of the battery 12 and the DCR. Figure 7 The horizontal axis represents the usage time of the battery 12 replaced with a new one. Figure 7 The vertical axis represents the DCR of the battery 12 .

[0116] exist Figure 7 The DCR of the battery 12 calculated each time the degradation diagnosis mode is executed is plotted in FIG. Figure 7 As shown in FIG. 1 , as the battery 12 is used for a longer time, the DCR increases. Figure 7 In the example of FIG. 1 , the longer the usage time is, the greater the increase in DCR relative to the cycle of executing the degradation diagnosis mode is.

[0117] return Figure 5 , the threshold value generating unit 42 sets the threshold value DCRth. In one aspect, the threshold value generating unit 42 can set the threshold value DCRth by amplifying a reference value (e.g., a design value) predetermined for the battery 12 by M times. Here, M is a number greater than 1. By setting the threshold value DCRth using the reference value of DCR in this way, the degradation of the battery 12 can be determined based on the increase (relative ratio) of DCR relative to the reference value.

[0118] On the other hand, the threshold value generating unit 42 can generate a threshold value based on the relationship between the usage time of the battery 12 and the DCR stored in the storage unit 40 ( Figure 7 Specifically, the threshold value generating unit 42 sets the threshold value DCRth by calculating the DCR value (equivalent to the value of DCR at the beginning of the use of the battery 12) Figure 7 The threshold value DCRth is set by amplifying the DCRi of the input signal by N times (DCRth=DCRi×N). Wherein, N is a number greater than 1.

[0119] By setting the threshold value DCRth using the DCRi at the initial stage of use of the battery 12, it is possible to determine the degradation of the battery 12 based on the increase (relative ratio) of DCR relative to DCRi. In a battery with a small DCRi, although the calculated value of DCR does not reach M times the above-mentioned reference value, the rate of progression of degradation sometimes tends to increase due to some abnormality. By setting the threshold value DCRth using DCRi, it is possible to detect the abnormality of rapid progression of battery degradation as early as possible regardless of individual differences in the battery.

[0120] Figure 8 This is a flowchart showing the flow of the deterioration diagnosis process of the battery 12 according to the first embodiment.

[0121] like Figure 8 As shown, in step (hereinafter, abbreviated as “S”) 01 , control device 10 shifts to the degradation diagnosis mode when time TD measured by timer 26 exceeds predetermined time Tc during execution of the normal mode.

[0122] In the degradation diagnosis mode, the control device 10 first stops the operation of the bidirectional chopper 7 in S02, thereby stopping the charging of the battery 12. Figure 6 As shown, by stopping the charging of the battery 12, the battery voltage VB drops.

[0123] In S03, the control device 10 determines the timing (from the time when the charging of the battery 12 is stopped) based on the output signal TDf of the timer 26 and the output signal VBf of the voltage detector 24. Figure 6 The time at which a predetermined time T1 has elapsed since the time t1 Figure 6 At time t2), the battery voltage VB1 is measured.

[0124] In S04, the control device 10 compares the battery voltage VB1 with the threshold voltage Vth. When VB1<Vth (when the determination in S04 is No), in S14, it is determined that the battery 12 is deteriorated, and the degradation detection signal VB1 is set to "H" level. The output is output to output unit 27. In S14, output unit 27 notifies the user of uninterruptible power supply 100 of the fact that battery 12 is deteriorating by using sound, light, images, and the like.

[0125] On the other hand, when VB1 ≥ Vth (YES in S04), control device 10 in S05 performs pulse discharge of battery 12 for a predetermined time T2 based on output signal TDf of timer 26. In S05, control device 10 discharges battery 12 at a constant current value.

[0126] During execution of the pulse discharge, the control device 10 measures the minimum voltage of the battery 12 (battery voltage VB2 ) based on the output signal VBf of the voltage detector 24 at S06 .

[0127] Next, the control device 10 measures the time ( ) from which the pulse discharge is stopped based on the output signal VBf of the voltage detector 24 in S07. Figure 6 At the time ( Figure 6 The battery voltage VB3 at time t5).

[0128] In S08 , the control device 10 calculates the DCR of the battery 12 by using the battery voltages VB2 and VB3 measured in S06 and S07 and the current value I during pulse discharge according to the equation (1).

[0129] In S09, the control device 10 generates a state signal indicating the degradation state of the battery 12 based on the DCR calculated in S08. The output unit 27 outputs the state signal based on the state signal. Information on the degradation state of battery 12 is presented to the user of uninterruptible power supply device 100. In S09, for example, output unit 27 causes the image display unit of operation unit 9 (or a display of an external device) to display a graph showing the time transition of the calculated value of DCR calculated each time the degradation diagnosis mode is executed (see FIG. Figure 7 ).

[0130] Through S10 , the control device 10 stores the DCR calculated in S08 in the internal memory.

[0131] In S11, the control device 10 compares the DCR calculated in S08 with the threshold value DCRth. When DCR≦DCRth (when the determination in S11 is NO), the control device 10 determines in S12 that the battery 12 is not degraded and sets the degradation detection signal Then, in S13, control device 10 sets reset signal RST to "H" level for a predetermined time to reset timer 26. Timer 26 after reset restarts measuring time TD from 0 seconds. Thus, the degradation diagnosis mode ends and shifts to the normal mode.

[0132] On the other hand, when DCR>DCRth (if it is determined to be YES in S11), the control device 10 determines that the battery 12 is deteriorated in S14, and turns the degradation detection signal The data is output to output unit 27. In S15, output unit 27 notifies the user of uninterruptible power supply 100 that battery 12 is deteriorating.

[0133] <Effect>

[0134] As described above, in the first embodiment, the degradation state of the battery 12 is diagnosed based on the battery voltage VB1 at the time point when the predetermined time T1 has passed since the charging of the battery 12 was stopped. Thus, the degradation diagnosis of the battery 12 can be performed without subjecting the battery 12 to a test discharge. In addition, by setting the predetermined time T1 to include the time for the battery voltage VB to relax after the charging of the battery 12 is stopped (for example, about 30 minutes to 1 hour), the influence of the relaxation of the battery voltage VB after the charging is stopped can be reduced, and the capacity degradation of the battery 12 can be diagnosed with high accuracy.

[0135] In the first embodiment, pulse discharge is performed after a predetermined time T1 has elapsed after charging of the battery 12 is stopped, and the DCR of the battery 12 is calculated based on the minimum voltage VB2 during the pulse discharge and the battery voltage VB3 immediately after the pulse discharge.

[0136] Here, the DCR of the battery 12 may also be calculated based on the battery voltage VB1 before the start of the pulse discharge and the minimum voltage VB2 during the pulse discharge. However, the battery voltage VB1 includes the influence of the relaxation of the battery voltage VB after the charging is stopped, although it is small, so the accuracy of the DCR may be reduced. In contrast, in the first embodiment, by calculating the DCR based on the minimum voltage VB2 during the pulse discharge and the battery voltage VB3 immediately after the pulse discharge, the influence of the relaxation of the battery voltage VB can be reduced, and the DCR can be calculated with high accuracy.

[0137] Furthermore, when the predetermined time T1 is set to a sufficiently long time in consideration of the relaxation characteristics of the battery voltage VB, the influence of relaxation included in the battery voltage VB1 after the predetermined time T1 has passed becomes smaller. In this case, the DCR can be calculated based on the battery voltage VB1 and the minimum voltage VB2 in the pulse discharge.

[0138] Furthermore, by using DCRi at the initial stage of use of the battery 12 to set the threshold value DCRth to be compared with the calculated DCR, an abnormality in which the progress of battery degradation is accelerated can be detected at an early stage regardless of individual differences in the battery.

[0139] [Implementation Method 2]

[0140] In the first embodiment, pulse discharge is performed during the execution of the degradation diagnosis mode, and the DCR of the battery 12 is calculated based on the minimum voltage VB2 during the pulse discharge, the battery voltage VB3 immediately after the pulse discharge, and the current value during the pulse discharge. However, there is a concern that pulse discharge at a constant current may not be performed when the uninterruptible power supply device 100 is lightly loaded. The second embodiment solves this concern.

[0141] The configuration and operation of uninterruptible power supply 100 according to the second embodiment are the same as those of uninterruptible power supply 100 according to the first embodiment, except for the processing in the degradation diagnosis mode described below.

[0142] <Degradation diagnosis processing>

[0143] Fig. 9 is a diagram for explaining the degradation diagnosis process in the degradation diagnosis unit 38 of the second embodiment, and is similar to Figure 6 Comparison chart. Fig. 9 2 shows the waveform of the battery voltage VB indicated by the output signal VBf of the voltage detector 24 and the waveforms of the charging command and the discharging command generated by the command generating unit 32 . Fig. 9 The degradation diagnosis process shown is similar to Figure 6 The degradation diagnosis process shown is different in that the pulse discharge of the battery 12 is replaced by pulse charge.

[0144] Specifically, during the execution of the degradation diagnosis mode, the discharge command is maintained at the "L" level. The discharge command is temporarily set to the "H" level for a predetermined time T4 from time t7 to time t8 after a predetermined time T1 elapses from time t2 at which the charging of the battery 12 is stopped. The predetermined time T4 is set to about 1 second, for example.

[0145] The charge and discharge control unit 36 ​​operates the bidirectional chopper 7 in response to the "H" level charge command, thereby executing pulse charging of the battery 12. The charge and discharge control unit 36 ​​controls the bidirectional chopper 7 so that the battery voltage VB becomes the reference DC voltage VBR during the predetermined time T4. During the execution of the pulse charging, the battery 12 is charged at a constant current value.

[0146] During the execution of pulse charging, the battery voltage VB rises. Specifically, immediately after the start of pulse charging, the battery voltage VB rises sharply due to the internal resistance of the battery 12, and then gradually rises. The degradation diagnosis unit 38 measures the maximum voltage of the battery 12 during the execution of pulse charging based on the output signal VBf of the voltage detector 24. In the following description, the measured value of the maximum voltage during the execution of pulse charging is expressed as "battery voltage VB4". The battery voltage VB4 is equivalent to the battery voltage VB at time t8 when the pulse charging is stopped.

[0147] By stopping the pulse charging at time t8, the battery voltage VB starts to decrease. Immediately after stopping the pulse charging, the battery voltage VB drops sharply. This voltage drop occurs due to the current during charging and the internal resistance of the battery 12. Thereafter, the battery voltage VB gradually decreases.

[0148] The degradation diagnosis unit 38 measures the battery voltage VB at time t9 after a predetermined time T5 has passed since the time t8 when the pulse charging is stopped, based on the output signal VBf of the voltage detector 24. The predetermined time T5 is set to, for example, several tens of milliseconds to about one second. In the following description, the measured value of the battery voltage VB at time t9 is expressed as "battery voltage VB5".

[0149] Next, degradation diagnosis unit 38 calculates DCR of battery 12 using battery voltage VB4 which is the maximum voltage during pulse charging, battery voltage VB5 immediately after pulse charging, and current value I during pulse charging. DCR is calculated by the following equation (2).

[0150] DCR=(VB4-VB5) / I···(2)

[0151] The degradation diagnosis unit 38 determines the degradation state of the battery 12 based on the calculated DCR. As described in the first embodiment, the degradation diagnosis unit 38 determines the progress of the degradation of the battery 12 by, for example, comparing the DCR calculated in the past degradation diagnosis mode with the DCR calculated in the current degradation diagnosis mode. Specifically, the degradation diagnosis unit 38 determines the progress of the degradation of the battery 12 based on the increase in the DCR relative to the cycle of executing the degradation diagnosis mode, and generates a status signal according to the determination result.

[0152] Furthermore, the degradation diagnosis section 38 determines whether the battery 12 has degraded based on the calculated DCR. Specifically, the degradation diagnosis section 38 compares the calculated DCR with the threshold value DCRth supplied from the threshold value generating section 42, and generates a degradation detection signal based on the comparison result. When DCR≦DCRth, it is determined that the battery 12 is not degraded, and the degradation detection signal When DCR>DCRth, it is determined that the battery 12 is degraded, and the degradation detection signal is set to “H” level.

[0153] Fig.10 This is a flowchart showing the flow of the deterioration diagnosis process of the battery 12 according to the second embodiment. Fig.10 The flowchart shown will Figure 8 The processes of S05 to S07 in the flowchart shown are replaced with S05A to S07A.

[0154] like Fig.10 As shown, in Figure 8 Similarly, when VB1 ≥ Vth in S04 (YES in S04), control device 10 in S05A performs pulse charging of battery 12 for a predetermined time T4 based on output signal TDf of timer 26. In S05A, control device 10 charges battery 12 at a constant current value.

[0155] During execution of pulse charging, control device 10 measures the maximum voltage of battery 12 (battery voltage VB4 ) based on output signal VBf of voltage detector 24 at S06A.

[0156] Next, the control device 10 measures the time ( ) from which the pulse charging is stopped based on the output signal VBf of the voltage detector 24 at S07A. Fig. 9 At the time ( Fig. 9 The battery voltage VB5 at time t9).

[0157] In S08, the control device 10 uses the battery voltages VB4 and VB5 measured in S06A and S07A and the current value I during pulse charging to calculate the DCR of the battery 12 using equation (2). The control device 10 uses the calculated DCR to perform the same Figure 8 The same processing of S09 to S15 is performed.

[0158] <Effect>

[0159] According to the second embodiment, the same effects as those of the first embodiment can be obtained. Furthermore, even when the uninterruptible power supply device 100 is lightly loaded, the DCR of the battery 12 can be calculated by executing the pulse charging of the battery 12 .

[0160] In addition, in embodiment 2, by calculating the DCR of the battery 12 based on the maximum voltage VB4 during pulse charging and the battery voltage VB5 immediately after pulse charging, the influence of relaxation of the battery voltage VB can be reduced, compared with the case of calculating based on the battery voltage VB1 before the start of pulse charging and the maximum voltage VB4 during pulse charging, and the DCR can be calculated with high accuracy.

[0161] However, when the predetermined time T1 is set to a sufficiently long time, the influence of relaxation included in the battery voltage VB1 after the predetermined time T1 has passed becomes smaller, and therefore the DCR may be calculated based on the battery voltage VB1 and the maximum voltage VB4 during pulse charging.

[0162] [Implementation method 3]

[0163] In the first and second embodiments, pulse discharge (or pulse charge) is performed during the execution of the degradation diagnosis mode, and the DCR of the battery 12 is calculated based on the amount of change in the battery voltage VB immediately after the pulse discharge (or pulse charge) and the current value during the pulse discharge (or pulse charge). In the third embodiment, the DCR of the battery 12 is calculated by performing either pulse discharge or pulse charge during the execution of the degradation diagnosis mode according to the magnitude of the load current.

[0164] The configuration and operation of uninterruptible power supply 100 according to the third embodiment are the same as those of uninterruptible power supply 100 according to the first embodiment, except for the processing in the degradation diagnosis mode described below.

[0165] Fig.11 and Fig.12 This is a flowchart showing the flow of the deterioration diagnosis process of the battery 12 according to the third embodiment. Fig.11 The flowchart shown is in Figure 8 The flowchart shown is a flowchart in which the process of S16 is added. Fig.12 The flowchart shown extracts Fig.10 The processing of S05A to S07A in the flowchart shown.

[0166] like Fig.11 As shown, in Figure 8Similarly, when VB1 ≥ Vth in S04 (when it is determined to be YES in S04), the control device 10 enters S16 and compares the load current Io indicated by the output signal Iof of the current detector CD3 with a predetermined reference current Ioth. The reference current Ioth is a load current used to determine whether the uninterruptible power supply device 100 is operating at a light load.

[0167] When Io≥Ioth (if determined as YES in S16), control device 10 determines that uninterruptible power supply device 100 is not operating at a light load. Figure 8 Similarly, through S05 to S07, the pulse discharge of the battery 12 is performed to measure the battery voltages VB2 and VB3. Figure 8 Similarly, through S08 to S15 , the DCR of the battery 12 is calculated based on the amount of change in the battery voltage VB and the current value during pulse discharge, and the deterioration state of the battery 12 is diagnosed using the calculated DCR.

[0168] On the other hand, when Io ≥ Ioth (if determined as YES in S16), control device 10 determines that uninterruptible power supply device 100 is operating at a light load. Fig.10 Similarly, through S05A to S07A, the pulse charging of the battery 12 is performed, and the battery voltages VB4 and VB5 are measured. Figure 8 Similarly, through S08 to S15 , the DCR of the battery 12 is calculated based on the amount of change in the battery voltage VB and the current value during pulse discharge, and the deterioration state of the battery 12 is diagnosed using the calculated DCR.

[0169] <Effect>

[0170] According to Embodiment 3, when the load of uninterruptible power supply device 100 varies, pulse discharge and pulse charge of battery 12 can be switched according to the load size. Thus, DCR of battery 12 can be calculated regardless of the load size to diagnose the degradation state of battery 12.

[0171] [Implementation Method 4]

[0172] In the uninterruptible power supply device to which the deterioration diagnosis method of the battery 12 of this embodiment is applied, in addition to Figure 1 In addition to the uninterruptible power supply device 100 shown, it can also include Fig.13 The uninterruptible power supply device 110 is shown. The uninterruptible power supply device 110 is also called a transient reduction compensation device.

[0173] Fig.13FIG. 1 is a circuit block diagram showing the configuration of an uninterruptible power supply device 110 according to Embodiment 4. The uninterruptible power supply device 110 supplies three-phase AC power to a load. Fig.13 Only the part related to one phase is shown.

[0174] like Fig.13 As shown, the uninterruptible power supply device 110 includes an input terminal 1, an output terminal 3, a DC terminal 2, circuit breakers B1 to B4, a high speed switch (HSS; High Speed ​​Switch) 51, a transformer 53, a bidirectional converter 52, and a control device 55. The uninterruptible power supply device 110 and Figure 1 The uninterruptible power supply 100 shown is different in that it includes an HSS 51 , a transformer 53 , a bidirectional converter 52 , and a control device 55 instead of the converter 4 , the bidirectional chopper 7 , the inverter 8 , and the control device 10 .

[0175] The circuit breakers B1 to B4 are, for example, VCBs (Vacuum Circuit Breakers). The circuit breaker B1 is connected between the input terminal 1 and the output terminal 3. When the uninterruptible power supply device 110 is used, the circuit breaker B1 is disconnected. When the uninterruptible power supply device 110 is maintained, the circuit breaker B1 is turned on, and the AC input voltage VI from the AC power supply 11 is supplied to the load 13 via the circuit breaker B1.

[0176] The circuit breaker B2 is connected between the input terminal 1 and one terminal 51a of the HSS 51. The circuit breaker B3 is connected between the other terminal 51b of the HSS 51 and the output terminal 3. When the uninterruptible power supply device 110 is used, the circuit breakers B2 and B3 are turned on. When the uninterruptible power supply device 110 is maintained, the circuit breakers B2 and B3 are turned off.

[0177] The HSS 51 is composed of, for example, a semiconductor switching element and is controlled by the control device 55. When the AC power source 11 is healthy (normal mode and degradation diagnosis mode), the HSS 51 is turned on, and the AC input voltage VI from the AC power source 11 is supplied to the load 13 via the circuit breaker B2, the HSS 51, and the circuit breaker B3. When the AC power source 11 fails (standby mode), the HSS 51 is turned off, and the AC power source 11 and the load 13 are electrically disconnected. The instantaneous value of the AC voltage VO appearing at the other terminal 51b of the HSS 51 is detected by the control device 55.

[0178] The circuit breaker B4 is connected between the other terminal 51b of the HSS51 and the primary winding 53b of the transformer 53. When the uninterruptible power supply device 110 is in use, the circuit breaker B4 is turned on. When the uninterruptible power supply device 110 is maintained, the circuit breaker B4 is turned off. The secondary winding 53a of the transformer 53 is connected to the AC terminal 52b of the bidirectional converter 52. The transformer 53 transmits and receives AC power between the other terminal 51b of the HSS51 and the AC terminal 52b of the bidirectional converter 52. The instantaneous value of the AC voltage VAC appearing at the AC terminal 52b of the bidirectional converter 52 is detected by the control device 55.

[0179] The DC terminal 52a of the bidirectional converter 52 is connected to the DC terminal 2. The bidirectional converter 52 is controlled by the control device 55. When the AC power source 11 is healthy (normal mode), the bidirectional converter 52 converts the AC power supplied from the AC power source 11 via the circuit breaker B2, the HSS 51, the circuit breaker B4, and the transformer 53 into DC power and stores it in the battery 12. When the AC power source 11 fails (standby mode), the bidirectional converter 52 converts the DC power of the battery 12 into AC power of commercial frequency and supplies it to the load 13 via the transformer 53 and the circuit breakers B4 and B3. The bidirectional converter 52 corresponds to an embodiment of the "power converter".

[0180] The control device 55 controls the HSS 51 and the bidirectional converter 52 based on the AC voltages VI, VO, VAC and the battery voltage VB. That is, when the AC power source 11 is healthy, The control device 55 executes the normal mode. In the normal mode, the control device 55 closes the circuit breakers B2 to B4 and the HSS 51. In addition, the control device 55 controls the bidirectional converter 52 in synchronization with the AC input voltage VI so that the battery voltage VB becomes the reference DC voltage VBR.

[0181] When the battery voltage VB reaches the reference DC voltage VBR, the control device 55 controls the bidirectional converter 52 to convert the battery voltage VB into an AC voltage VAC of a commercial frequency.

[0182] If the phase of the AC output voltage VAC of the bidirectional converter 52 is made to be ahead of the phase of the AC input voltage VI from the AC power source 11, electric power flows from the battery 12 to the load 13 via the bidirectional converter 52, and the battery voltage VB decreases. If the phase of the AC output voltage VAC is made to be delayed from the phase of the AC input voltage VI, electric power flows from the AC power source 11 to the battery 12 via the bidirectional converter 52, and the battery voltage VB increases. The control device 55 controls the bidirectional converter 52 to adjust the phase of the AC voltage VAC, and maintains the battery voltage VB at the reference DC voltage VBR.

[0183] When a power outage occurs in the AC power source 11 The control device 55 executes the standby mode. In the standby mode, the control device 55 turns off the HSS 51 and controls the bidirectional converter 52 so that the AC voltage VO becomes the reference AC voltage VOR. When the AC power supply 11 recovers from the power failure state to the normal state The control device 55 shifts from the standby mode to the normal mode. The control device 55 controls the bidirectional converter 52 so that the phase and frequency of the AC voltage VO match the phase and frequency of the AC input voltage VI, and then turns on the HSS 51.

[0184] In the execution of the normal mode, when the time TD indicated by the output signal TDf of the timer (not shown) exceeds the predetermined time Tc, the control device 55 executes the degradation diagnosis mode. In the degradation diagnosis mode, the control device 55 diagnoses the degradation state of the battery 12 while supplying AC power to the load 13. The control device 55 controls the operation of the bidirectional converter 52 based on the output signal TDf of the timer. In one aspect, as Figure 6 As shown, the control device 55 stops charging the battery 12 by stopping the operation of the bidirectional converter 52 for a predetermined time T1, and determines whether the battery 12 is degraded based on the battery voltage VB1 at the time when the predetermined time T1 has passed since the charging was stopped. The control device 55 further performs pulse discharge of the battery 12, and calculates the DCR of the battery 12 based on the minimum voltage VB2 during the pulse discharge and the battery voltage VB2 immediately after the pulse discharge. The control device 55 determines the degradation state of the battery 12 based on the calculated DCR, and compares the calculated DCT with the threshold value DCRth, and determines whether the battery 12 is degraded based on the comparison result.

[0185] On the other hand, Fig. 9 As shown, the control device 55 stops the charging of the battery 12 by stopping the operation of the bidirectional converter 52 for a predetermined time T1, and determines whether the battery 12 is degraded based on the battery voltage VB1 at the time when the predetermined time T1 has passed since the charging was stopped. The control device 55 further performs pulse charging of the battery 12, and calculates the DCR of the battery 12 based on the maximum voltage VB4 during the pulse charging and the battery voltage VB5 after the pulse charging. The control device 55 determines the degradation state of the battery 12 based on the calculated DCR, and compares the calculated DCR with the threshold value DCRth, and determines whether the battery 12 is degraded based on the comparison result. When the execution of the degradation diagnosis mode is terminated, the control device 55 resets the timer by making the reset signal RST become the "H" level of the active level for a predetermined time, and executes the normal mode again.

[0186] In addition, when a power failure of the AC power supply 11 occurs during the execution of the degradation diagnosis mode, Control device 55 executes the standby mode. In response to the interruption of the execution of the degradation diagnosis mode, control device 55 sets reset signal RST to the "H" level, which is an active level, for a predetermined time to reset the timer.

[0187] <Effect>

[0188] In the fourth embodiment, the same effects as those in the first embodiment can be obtained. In the fourth embodiment, when the load of the uninterruptible power supply device 110 varies, the pulse discharge and pulse charge of the battery 12 can be switched according to the load size. Thus, the DCR of the battery 12 can be calculated regardless of the load size to diagnose the deterioration state of the battery 12.

[0189] [Other configuration examples]

[0190] In the above-mentioned embodiments 1 to 4, the configuration for diagnosing the degradation state of the battery used in the uninterruptible power supply device is described, but the degradation diagnosis method of this embodiment can also be applied to the configuration for diagnosing the degradation state of each of the plurality of battery modules constituting the battery. For example, the terminal voltage of each battery module at the moment when a predetermined time has passed since the charging of the battery was stopped can be measured, and the degradation state of the battery module can be diagnosed based on the measured value of the terminal voltage. In addition, by calculating the DCR of the battery module based on the change in the terminal voltage of each battery module immediately after the pulse discharge or pulse charging of the battery, the degradation state of the battery module can be judged based on the calculated value of the DCR.

[0191] Furthermore, the degradation diagnosis method of the present embodiment can also be applied to a configuration for diagnosing the degradation state of each of a plurality of battery cells constituting a battery module. In one aspect, the terminal voltage of each battery cell at a time when a predetermined time has passed since the charging of the storage battery was stopped can be measured, and the degradation state of the battery cell can be diagnosed based on the measured value of the terminal voltage. In addition, by calculating the DCR of the battery cell based on the change in the terminal voltage of each battery cell immediately after the pulse discharge or pulse charging of the battery, the degradation state of the battery cell can be determined based on the calculated value of the DCR.

[0192] The embodiments disclosed herein should be considered to be illustrative in all aspects and not restrictive. The present disclosure is indicated by the claims rather than the above description, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0193] Description of Reference Numerals

[0194] 1 input terminal; 2 DC terminal; 3 output terminal; 4 converter; 5 DC line; 6 capacitor; 7 bidirectional chopper; 8 inverter; 9 operating unit; 10, 55 control device; 11 AC power supply; 12 battery; 13 load; 21-24 voltage detectors; 25 power failure detector; 26 timer; 27 output unit; 28 control circuit; 30 mode setting unit; 32 instruction generation unit; 34 power supply control unit; 36 charge and discharge control unit; 38 degradation diagnosis unit; 40 storage unit; 42 threshold value generation unit; 51 HSS; 52 bidirectional converter; 53 transformer; 100, 110 uninterruptible power supply device; 102 CPU; 104 memory; 106 I / O circuit; 108 bus; S1-S3 switches; CD1-CD3 current detectors; B1-B4 circuit breakers.

Claims

1. An uninterruptible power supply device, comprising: a normal mode in which power supplied from an AC power source is supplied to a load; a standby mode in which power stored in a battery is supplied to the load when the AC power source fails; and a degradation diagnosis mode in which a degradation state of the battery is diagnosed, wherein: have: a power converter for performing float charging on the storage battery using the power supplied from the AC power source in the normal mode and for discharging the storage battery in the standby mode; as well as Control device, The control device periodically shifts to the degradation diagnosis mode during execution of the normal mode, In the execution of the degradation diagnosis mode, the control device is: stopping the charging of the battery by stopping the operation of the power converter, measuring the voltage of the storage battery at a first timing when a first time has passed since charging of the storage battery was stopped; The degradation state of the storage battery is diagnosed based on the measured value of the voltage of the storage battery at the first timing.

2. The uninterruptible power supply device according to claim 1, wherein: The control device further In a second time after the first timing, the power converter is operated to perform pulse discharge of the storage battery, determining a minimum voltage of the battery during the pulse discharge, measuring the voltage of the battery at a second timing when a third time has passed since the pulse discharge was stopped, calculating the DC resistance of the battery based on the minimum voltage, the measured value at the second timing, and the current value during the pulse discharge, A degradation state of the battery is diagnosed based on the calculated value of the DC resistance.

3. The uninterruptible power supply device according to claim 1, wherein: The control device further In a second time after the first timing, the power converter is operated to perform pulse charging of the storage battery, measuring the maximum voltage of the battery during the pulse charging, measuring the voltage of the battery at a second timing when a third time has passed since the pulse charging was stopped, calculating the DC resistance of the battery based on the maximum voltage, the measured value at the second timing, and the current value during the pulse charging, A degradation state of the battery is diagnosed based on the calculated value of the DC resistance.

4. The uninterruptible power supply device according to claim 1, wherein: The control device further When the load current supplied to the load is greater than a predetermined reference current, In a second time after the first timing, the power converter is operated to perform pulse discharge of the storage battery, determining a minimum voltage of the battery during the pulse discharge, measuring the voltage of the battery at a second timing when a third time has passed since the pulse discharge was stopped, calculating the DC resistance of the battery based on the minimum voltage, the measured value at the second timing, and the current value during the pulse discharge, A degradation state of the battery is diagnosed based on the calculated value of the DC resistance.

5. The uninterruptible power supply device according to claim 4, wherein: The control device further When the load current is less than the reference current, In a fourth time after the first timing, the power converter is operated to perform pulse charging of the storage battery, measuring the maximum voltage of the battery during the pulse charging, measuring the voltage of the battery at a fourth timing when a fifth time has passed since the pulse charging was stopped, calculating the DC resistance of the battery based on the maximum voltage, the measured value at the fourth timing, and the current value during the pulse charging, A degradation state of the battery is diagnosed based on the calculated value of the DC resistance.

6. The uninterruptible power supply device according to any one of claims 2 to 5, wherein: The control device generates a state signal indicating a degradation state of the battery based on a time transition of a calculated value of the DC resistance calculated each time the degradation diagnosis mode is executed, The uninterruptible power supply device further includes an output unit that presents information on the degradation state of the storage battery to a user of the uninterruptible power supply device based on the state signal.

7. The uninterruptible power supply device according to any one of claims 2 to 5, wherein: The control device is: storing the battery usage time and the calculated value of the DC resistance in a storage unit in correspondence with each other, The threshold value is set by amplifying the DC resistance at the initial use of the storage battery stored in the storage unit by a predetermined multiple, When the calculated value of the DC resistance is larger than the threshold value, it is diagnosed that the battery is deteriorated.

8. The uninterruptible power supply device according to claim 1, wherein: When a power failure of the AC power source occurs during execution of the degradation diagnosis mode, the control device shifts to the standby mode.

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