WO2024127578A1 - Uninterruptible power supply system - Google Patents

Uninterruptible power supply system Download PDF

Info

Publication number
WO2024127578A1
WO2024127578A1 PCT/JP2022/046179 JP2022046179W WO2024127578A1 WO 2024127578 A1 WO2024127578 A1 WO 2024127578A1 JP 2022046179 W JP2022046179 W JP 2022046179W WO 2024127578 A1 WO2024127578 A1 WO 2024127578A1
Authority
WO
WIPO (PCT)
Prior art keywords
power
power supply
load
current
bypass
Prior art date
Application number
PCT/JP2022/046179
Other languages
French (fr)
Japanese (ja)
Inventor
亮五 今西
Original Assignee
東芝三菱電機産業システム株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 東芝三菱電機産業システム株式会社 filed Critical 東芝三菱電機産業システム株式会社
Priority to PCT/JP2022/046179 priority Critical patent/WO2024127578A1/en
Publication of WO2024127578A1 publication Critical patent/WO2024127578A1/en

Links

Images

Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J9/00—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting
    • H02J9/04—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source
    • H02J9/06—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source with automatic change-over, e.g. UPS systems

Definitions

  • This disclosure relates to an uninterruptible power supply system, and in particular to an uninterruptible power supply system having multiple uninterruptible power supply devices connected in parallel to a load.
  • Patent Document 1 discloses an uninterruptible power supply including a bypass switch, a small semiconductor switch, and a power converter connected in parallel between an AC power source and a load.
  • the power converter includes a converter that converts AC power supplied from the AC power source into DC power, and an inverter that converts the DC power into AC power and supplies it to the load.
  • the inverter power supply mode is executed and the bypass switch and semiconductor switch are turned off.
  • the converter also converts AC power from the AC power supply into DC power. This DC power is stored in the battery and is also provided to the inverter.
  • the inverter converts the DC power into AC power and supplies it to the load.
  • the bypass power supply mode is executed, the operation of the power converter is stopped, and the bypass switch and semiconductor switch are turned on. To prevent the semiconductor switch from overheating due to current, the semiconductor switch is turned off after a specified time has elapsed. AC power is supplied to the load from the AC power source via the bypass switch.
  • the battery power supply mode is activated, the converter operation is stopped, and the inverter converts the DC power of the battery into AC power and supplies it to the load. Therefore, even if a power outage occurs in the AC power supply, the load can continue to operate as long as DC power is stored in the battery.
  • uninterruptible power supplies have the problem that losses occur mainly in the power converter, resulting in low efficiency of around 90-96%.
  • uninterruptible power supplies with a bypass ECO power supply mode have attracted attention.
  • These uninterruptible power supplies are equipped with a large semiconductor switch and a power converter that are connected in parallel between the AC power supply and the load.
  • the bypass ECO power supply mode is executed, the semiconductor switch is turned on, and AC power from the AC power supply is supplied to the load via the semiconductor switch.
  • the battery power supply mode is executed, the semiconductor switch is turned off, and the inverter included in the power converter converts the battery's DC power to AC power and supplies it to the load.
  • losses occur mainly in the semiconductor switch, but because the losses in the semiconductor switch are smaller than the losses in the power converter, a high efficiency of 99% can be achieved.
  • the primary objective of this disclosure is to provide an uninterruptible power supply system that enables miniaturization and cost reduction of semiconductor switches.
  • the uninterruptible power supply system disclosed herein includes a plurality of uninterruptible power supply devices connected in parallel to a load.
  • Each uninterruptible power supply device includes a semiconductor switch that is turned on when the first AC power supply is healthy and turned off when the first AC power supply is interrupted, a reactor that is connected in series with the semiconductor switch between the first AC power supply and the load, and a power converter that converts DC power supplied from a DC power supply into AC power and supplies it to the load when the first AC power supply is interrupted.
  • each of the multiple uninterruptible power supply devices includes a semiconductor switch and a reactor connected in series between the first AC power supply and the load, so that when each semiconductor switch is turned on, the load current is diverted to the series connection of the multiple semiconductor switches and reactors. Therefore, compared to a case where there is no reactor, the variation in the magnitude of the current flowing through the multiple semiconductor switches can be reduced, and the semiconductor switches can be made smaller and less expensive.
  • FIG. 1 is a circuit block diagram showing a configuration of an uninterruptible power supply system according to an embodiment of the present disclosure.
  • FIG. 2 is a block diagram showing a configuration of a control device shown in FIG. 1 .
  • 2 is a circuit block diagram showing a configuration of the uninterruptible power supply device shown in FIG. 1.
  • FIG. 4 is a circuit block diagram showing a configuration of the bypass module shown in FIG. 3 .
  • FIG. 5 is a diagram showing a table stored in a storage unit shown in FIG. 4 .
  • FIG. 4 is a circuit block diagram showing a configuration of the power module shown in FIG. 3 .
  • 7 is a block diagram showing a configuration of a portion of the control unit shown in FIG. 6 that is related to inverter control.
  • FIG. 1 is a circuit block diagram showing a main part of an uninterruptible power supply system serving as a comparative example of an embodiment.
  • FIG. 11 is a circuit block diagram for explaining a bypass ECO power supply mode in a comparative example.
  • FIG. 10 is a diagram illustrating the VI characteristics of the semiconductor switch shown in FIG.
  • FIG. 4 is a circuit block diagram for explaining a bypass ECO power supply mode in the embodiment.
  • 12 is a diagram illustrating the VI characteristics of the reactor shown in FIG. 11.
  • 12 is a diagram illustrating an example of a VI characteristic of a series connection of the reactor and the semiconductor switch shown in FIG. 11.
  • FIG. 1 is a circuit block diagram showing the configuration of an uninterruptible power supply system 1 according to one embodiment of the present disclosure.
  • the uninterruptible power supply system 1 comprises N uninterruptible power supplies (UPS) U1-UN, N batteries B1-BN, a current detector 2, a communication line 3, an operation unit 4, and a control device 5.
  • N is an integer equal to or greater than 2.
  • the uninterruptible power supplies U1-UN may be collectively and representatively referred to as uninterruptible power supply U.
  • the batteries B1-BN may be collectively and representatively referred to as battery B.
  • Each uninterruptible power supply U includes a bypass terminal T1, an input terminal T2, a DC terminal T3, and an output terminal T4.
  • the bypass terminal T1 is connected to a bypass AC power supply 6 (first AC power supply).
  • the input terminal T2 is connected to an AC power supply 7 (second AC power supply).
  • the bypass AC power supply 6 and the AC power supply 7 may be provided separately or may be the same.
  • Each of the AC power supplies 6, 7 may be a commercial AC power supply or a generator.
  • Each of the AC power supplies 6, 7 supplies AC power to the uninterruptible power supplies U1 to UN.
  • the DC terminals T3 of the uninterruptible power supplies U1 to UN are connected to batteries B1 to BN (power storage devices), respectively.
  • Each of the batteries B1 to BN stores DC power.
  • a single large battery may be provided in place of the batteries B1 to BN, and the DC terminals T3 of the uninterruptible power supplies U1 to UN may be connected to the single large battery.
  • a capacitor may be provided in place of the battery B.
  • the output terminals T4 of the uninterruptible power supplies U1 to UN are all connected to a node N1, which is connected to a load 8.
  • the load 8 is driven by AC power supplied from the uninterruptible power supply system 1.
  • the current detector 2 detects the current IL flowing between the node N1 and the load 8, and outputs a signal ⁇ IL indicating the detected value to the control device 5.
  • the uninterruptible power supplies U1-UN and the control device 5 are also connected to each other by a communication line 3.
  • the uninterruptible power supplies U1-UN and the control device 5 exchange various signals and information via the communication line 3.
  • the operation unit 4 includes a number of buttons, a number of switches, and an image display unit. By operating the operation unit 4, a user of the uninterruptible power supply system can operate the uninterruptible power supply system 1 automatically or can operate each uninterruptible power supply device U manually.
  • the operation unit 4 outputs signals and information indicating the content of operations performed by the user to the control device 5.
  • the control device 5 controls the entire uninterruptible power supply system 1 based on signals and information from the operation unit 4 and the uninterruptible power supplies U1 to UN, the output signal ⁇ IL of the current detector 2, etc. In particular, the control device 5 determines the shared current Is of each uninterruptible power supply U based on the load current IL indicated by the output signal ⁇ IL of the current detector 2. A signal indicating the shared current Is is provided to each uninterruptible power supply U via the communication line 3.
  • each uninterruptible power supply device U supplies AC power from the bypass AC power supply 6 to the load 8, and converts AC power from the AC power supply 7 to DC power to charge the corresponding battery B.
  • each uninterruptible power supply device U executes the battery power supply mode. At this time, each uninterruptible power supply device U converts the DC power of the corresponding battery B into AC power and supplies the shared current Is determined by the control device 5 to the load 8.
  • FIG. 2 is a block diagram showing the configuration of the control device 5.
  • the control device 5 includes a communication unit 11, a calculation unit 12, a control unit 13, and a notification unit 14.
  • the communication unit 11 is provided between the control unit 13 and the communication line 3, and transmits and receives various signals and information between the control unit 13 and each uninterruptible power supply device U.
  • the control unit 13 detects the number n of operable uninterruptible power supplies U based on signals from the operation unit 4 and the uninterruptible power supplies U, and provides a signal indicating the number n to the calculation unit 12.
  • n is an integer greater than or equal to 1 and less than or equal to N.
  • the control unit 13 outputs a signal ⁇ Is indicating the shared current Is to each uninterruptible power supply U via the communication unit 11 and the communication line 3.
  • the control unit 13 also outputs various signals and information to each uninterruptible power supply U via the communication unit 11 and the communication line 3 in accordance with the output signal of the operation unit 4.
  • the control unit 13 also provides a failure detection signal provided from the failed uninterruptible power supply U via the communication line 3 and the communication unit 11 to the notification unit 14.
  • the notification unit 14 notifies the user of the uninterruptible power supply system that a part of the uninterruptible power supply U has failed using sound, light, images, etc. The user then repairs the failed uninterruptible power supply U or replaces it with a new one.
  • FIG. 3 is a circuit block diagram showing the configuration of the uninterruptible power supply U1.
  • the uninterruptible power supply U1 includes a bypass switch 20, a reactor 21, a bypass module 22, and M power modules P1 to PM, where M is an integer equal to or greater than 2.
  • the power modules P1 to PM may be collectively and representatively referred to as a power module P.
  • the M power modules P1 to PM form one embodiment of a "power converter.”
  • Each of the other uninterruptible power supplies U2 to UN has a similar configuration to the uninterruptible power supply U1.
  • the bypass switch 20 is a mechanical switch, and is connected between the bypass terminal T1 and the output terminal T4.
  • the bypass switch 20 is turned on by the control device 5 when the operation unit 4 is operated to select the bypass power supply mode.
  • the N bypass switches 20 included in the N uninterruptible power supplies U1 to UN are turned on, and a load current IL is supplied from the bypass AC power supply 6 to the load 8 via the parallel connection of the N bypass switches 20.
  • the capacity of the bypass switches 20 is sufficiently large, so that a current of 1/N of the load current IL flows through each bypass switch 20.
  • the reactor 21 is connected between the bypass terminal T1 and one terminal 22a of the bypass module 22.
  • the other terminal 22b of the bypass module 22 is connected to the output terminal T4.
  • the reactor 21 may be connected between the other terminal 22b of the bypass module 22 and the output terminal T4. In this case, the one terminal 22a of the bypass module 22 is directly connected to the bypass terminal T1.
  • FIG. 4 is a circuit block diagram showing the configuration of the bypass module 22.
  • the bypass module 22 includes a semiconductor switch 23, a power outage detection unit 26, a communication unit 27, a control unit 28, and a memory unit 29.
  • the semiconductor switch 23 includes a pair of thyristors 24, 25 connected in antiparallel to each other.
  • the anode and cathode of the thyristor 24 are connected to the terminals 22a and 22b, respectively, of the bypass module 22.
  • the anode and cathode of the thyristor 25 are connected to the terminals 22b and 22a, respectively, of the bypass module 22.
  • the semiconductor switch 23 may be composed of semiconductor elements other than the thyristors 24 and 25 (e.g., transistors, diodes, etc.).
  • the semiconductor switch 23 is controlled by the control unit 28 and is turned on in the bypass ECO power supply mode. When the semiconductor switch 23 is turned on, AC power is supplied from the bypass AC power supply 6 to the load 8 via the reactor 21 and the semiconductor switch 23.
  • N semiconductor switches 23 are turned on, and a load current IL is supplied from the bypass AC power supply 6 to the load 8 via a series connection of N reactors 21 and semiconductor switches 23.
  • the reactor 21 is provided to reduce the variation in the magnitude of the current flowing through the N semiconductor switches 23 at this time. This will be described later.
  • the semiconductor switch 23 is turned off, and the bypass AC power supply 6 is instantly disconnected from the load 8.
  • the power outage detection unit 26 detects the instantaneous value of the AC voltage VI (i.e., the AC voltage VI supplied from the bypass AC power supply 6) that appears at the bypass terminal T1, determines whether or not a power outage has occurred in the bypass AC power supply 6 based on the detected value, and outputs a power outage detection signal ⁇ 26 that indicates the determination result.
  • the instantaneous value of the AC voltage VI i.e., the AC voltage VI supplied from the bypass AC power supply 6
  • the power outage detection unit 26 determines that the AC voltage VI is being supplied normally from the bypass AC power supply 6 and that the bypass AC power supply 6 is healthy.
  • the power outage detection unit 26 determines that the AC voltage VI is not being supplied normally from the bypass AC power supply 6 and that a power outage of the bypass AC power supply 6 has occurred.
  • the power outage detection signal ⁇ 26 When the bypass AC power supply 6 is healthy, the power outage detection signal ⁇ 26 is set to the inactive "H” level. When a power outage occurs in the bypass AC power supply 6, the power outage detection signal ⁇ 26 is set to the active "L” level.
  • the communication unit 27 is connected to the power modules P1-PM in the uninterruptible power supply U1, the other uninterruptible power supplies U2-UM, and the control device 5 via the communication line 3, and transmits and receives various signals and information between them and the control unit 28.
  • the control unit 28 turns on the semiconductor switch 23 when the control device 5 issues a command to execute the bypass ECO power supply mode via the communication line 3 and the communication unit 27, and the power failure detection signal ⁇ 26 is at the inactivation level of "H".
  • the control unit 28 turns off the semiconductor switch 23.
  • the power failure detection signal ⁇ 26 is provided to the power modules P1 to PM via the control unit 28, the communication unit 27, and the communication line 3.
  • the control unit 28 also selects the number m of power modules P required to efficiently supply the shared current Is indicated by the signal ⁇ Is provided from the control device 5 (FIG. 5) via the communication line 3 and the communication unit 27, and outputs signals SE1 to SEM indicating the selection result.
  • m is an integer greater than or equal to 1 and less than or equal to M.
  • the selection signals SE1 to SEM may be collectively referred to as the selection signal SE.
  • the reason for selecting m power modules P is that if all power modules P1 to PM were selected, the output current of each power module P would be too small, reducing the efficiency of each power module P.
  • the selection signals SE1 to SEM correspond to the power modules P1 to PM, respectively.
  • the selection signal SE corresponding to that power module P is set to the selection level "H”.
  • the selection signal SE corresponding to that power module P is set to the non-selection level "L”.
  • the control unit 28 calculates a sub-shared current Iss that is 1/m of the shared current Is, and provides a signal ⁇ Iss indicating the sub-shared current Iss to each power module P. In the event of a power outage in the bypass AC power supply 6, each of the selected m power modules P supplies a sub-shared current Iss that is 1/m of the shared current Is to the load 8.
  • control unit 28 changes the combination of the m power modules P to be selected each time a power outage occurs in the bypass AC power supply 6. This is to prevent a specific power module P from being repeatedly selected and deteriorating faster than other power modules P.
  • the memory unit 29 stores a table showing the combinations of the m power modules P.
  • FIG. 5 is a diagram showing a table stored in the memory unit 29.
  • 10 patterns are shown. In each pattern, the power module P marked with a circle is selected.
  • power modules P1 to P3 are selected out of the five power modules P1 to P5.
  • power modules P1, P2, and P4 are selected.
  • power modules P1, P2, and P5 are selected.
  • power modules P1, P3, and P4 are selected.
  • power modules P1, P3, and P5 are selected.
  • power modules P1, P4, and P5 are selected.
  • power modules P2 to P4 are selected.
  • power modules P2, P3, and P5 are selected.
  • power modules P2, P4, and P5 are selected.
  • power modules P3 to P5 are selected.
  • the control unit 28 selects three power modules P1 to P3 of pattern 1 the first time, selects three power modules P of patterns 2 to 10 the second to tenth times, and again selects three power modules P1 to P3 of pattern 1 the eleventh time. This is the same as above.
  • the control unit 28 selects one of the four tables according to the value of m, and refers to that table to select m power modules P.
  • each power module P includes an input terminal T5, a DC terminal T6, and an output terminal T7.
  • the input terminal T5, DC terminal T6, and output terminal T7 are connected to the input terminal T2, DC terminal T3, and output terminal T4 of the corresponding uninterruptible power supply U1, respectively.
  • the power module P converts the AC power supplied from the AC power source 7 into DC power and stores it in the corresponding battery B1.
  • the power module P stops charging the battery B1.
  • each power module P When the power failure detection signal ⁇ 26 (FIG. 4) is at the inactive "H" level during bypass ECO power supply mode, each power module P outputs a counter voltage VC that opposes the AC voltage VO appearing at the output terminal T4, and is placed in a standby state in which no current is exchanged with other power modules P or the load 8. In other words, at this time, each power module P outputs the counter voltage VC and outputs 0 A.
  • each of the m power modules P selected by the control unit 28 (FIG. 4) from among the power modules P1 to PM supplies the sub-shared current Iss indicated by the signal ⁇ Iss from the control unit 28 to the load 8.
  • FIG. 6 is a circuit block diagram showing the configuration of power module P1.
  • this power module P1 in addition to terminals T5 to T7 (FIG. 3), this power module P1 includes fuses F1 to F3, switches S1 to S3, capacitors C1 to C3, reactors L1 to L3, converter 31, DC line DL, inverter 32, bidirectional chopper 33, current detectors CD1 to CD3, communication unit 34, control unit 35, and fault detection unit 36.
  • Each of the other power modules P2 to PM has the same configuration as power module P1.
  • One terminal of the switch S1 is connected to the input terminal T5 via the fuse F1, and the other terminal is connected to the input node of the converter 31 via the reactor L1.
  • the capacitor C1 is connected to the other terminal of the switch S1.
  • the output node of the converter 31 is connected to the input node of the inverter 32 via the DC line DL, and is also connected to one input/output node of the bidirectional chopper 33.
  • the capacitor C3 is connected to the DC line DL.
  • the DC lines DL of the power modules P1 to PN are connected to each other.
  • the output node of the inverter 32 is connected to one terminal of a switch S2 via a reactor L2, and the other terminal of the switch S2 is connected to an output terminal T7 via a fuse F2.
  • a capacitor C2 is connected to one terminal of the switch S2.
  • One terminal of the switch S3 is connected to a DC terminal T6 via a fuse F3, and the other terminal is connected to the other input/output node of the bidirectional chopper 33 via a reactor L3.
  • Fuse F1 is blown when an overcurrent flows, protecting converter 31 and other components.
  • Switch S1 is controlled by control unit 35. When AC voltage Vi is being supplied normally from AC power supply 7 (when AC power supply 7 is functioning properly), switch S1 is turned on. When AC voltage Vi is not being supplied normally from AC power supply 7 (when AC power supply 7 is experiencing a power outage), switch S1 is turned off.
  • Capacitor C1 and reactor L1 form an AC filter.
  • the AC filter is a low-pass filter that passes commercial frequency AC power supplied from AC power source 7 and blocks the switching frequency signal generated by converter 31.
  • the converter 31 is controlled by the control unit 35, and when the AC power supply 7 is healthy, it converts the AC power from the AC power supply 7 into DC power and supplies the DC power to the inverter 32 and the bidirectional chopper 33 via the DC line DL.
  • the converter 31 outputs a DC current to the DC line DL so that the DC voltage VD of the DC line DL matches the target DC voltage VDT.
  • the capacitor C1, the reactor L1, and the converter 31 constitute one embodiment of a "forward converter” that converts AC power into DC power.
  • the capacitor C3 smoothes and stabilizes the DC voltage VD of the DC line DL.
  • Fuse F3 is blown in the event of an overcurrent, protecting battery B1, bidirectional chopper 33, etc.
  • Switch S3 is turned on when power module P1 is in use, and turned off, for example, during maintenance of battery B1.
  • Reactor L3 is a low-pass filter that passes DC power and blocks the switching frequency signal generated by bidirectional chopper 33.
  • the bidirectional chopper 33 is controlled by the control unit 35, and stores the DC power generated by the converter 31 in the battery B1 when the AC power supply 7 is healthy, and supplies the DC power of the battery B1 to the inverter 32 when the bypass AC power supply 6 fails.
  • the bidirectional chopper 33 supplies a DC current to the battery B1 so that the terminal voltage VB of the battery B1 becomes the target DC voltage VBT.
  • the bidirectional chopper 33 outputs a DC current to the DC line DL so that the DC voltage VD of the DC line DL becomes equal to the target DC voltage VDT.
  • the inverter 32 is controlled by the control unit 35.
  • the inverter 32 When the power failure detection signal ⁇ 26 (FIG. 4) is at the inactivation level "H", the inverter 32 outputs a counter voltage VC that opposes the AC voltage VO appearing at the output terminal T7, and is placed in a standby state in which it does not exchange current with the other power modules P2 to PM or the load 8. In other words, at this time the inverter 32 outputs the counter voltage VC and outputs 0 A.
  • the reactor L2 and the capacitor C2 form an AC filter.
  • the AC filter is a low-pass filter that passes commercial frequency AC power generated by the inverter 32 and blocks signals of the switching frequency generated by the inverter 32. In other words, the AC filter shapes the waveform of the output voltage of the inverter 32 into a sine wave.
  • the inverter 32, the reactor L2, and the capacitor C2 form one embodiment of an "inverter" that converts DC power to AC power.
  • the switch S2 is turned on when the power module P1 is used, and is turned off when the inverter 32 fails or during maintenance of the inverter 32.
  • the AC voltage Vi at the input terminal T5 i.e., the AC voltage supplied from the AC power source 7
  • the AC voltage VO at the output terminal T7 i.e., the output voltage
  • the DC voltage VB at the DC terminal T6 i.e., the voltage between the terminals of the battery B1
  • the DC voltage VD of the DC line DL are provided to the control unit 35.
  • Current detector CD1 detects the instantaneous value of the AC current flowing through reactor L1 (i.e., the input current of converter 31) and provides a signal indicating the detected value to control unit 35.
  • Current detector CD2 detects the instantaneous value of the AC current flowing through reactor L2 (i.e., the output current of inverter 32) and provides a signal indicating the detected value to control unit 35.
  • Current detector CD3 detects the instantaneous value of the DC current flowing through reactor L3 (i.e., the DC current flowing through battery B1) and provides a signal indicating the detected value to control unit 35.
  • the communication unit 34 is provided between the control unit 35 and the communication line 3, and transmits and receives various signals and information between the bypass module 22, the other power modules P2 to PM, and the control device 5.
  • the fault detection unit 36 determines whether the corresponding inverter 32 is normal or not, and outputs a fault detection signal ⁇ 36 indicating the determination result. If the inverter 32 is normal, the fault detection signal ⁇ 36 is set to the inactivation level "L" level. If the inverter 32 is faulty, the fault detection signal ⁇ 36 is set to the activation level "H" level.
  • the fault detection signal ⁇ 36 is given to the control unit 35.
  • the control unit 35 controls the inverter 32.
  • the control unit 35 stops the operation of the inverter 32 and turns off the switch S2.
  • Failure detection signal ⁇ 36 is also provided to control unit 28 via control unit 35, communication unit 34, communication line 3, and communication unit 27 (FIG. 4).
  • control unit 28 selects m power modules P from power modules P2 to PM other than the power module corresponding to that failure detection signal ⁇ 36 (P1 in this case).
  • the control unit 35 controls the entire power module P1 based on the instantaneous values of the AC voltages Vi, VO, the instantaneous values of the DC voltages VB, VD, the detection values of the current detectors CD1 to CD3, the fault detection signal ⁇ 36, and various signals and information supplied from the control device 5 and the control unit 28 via the communication line 3 and the communication unit 34.
  • control unit 35 controls the converter 31 based on the instantaneous value of the AC voltage Vi, the instantaneous value of the DC voltage VD of the DC line DL, the detection value of the current detector CD1, etc. As a result, the DC voltage VD of the DC line DL is maintained at the target DC voltage VDT.
  • the control unit 35 also controls the bidirectional chopper 33 based on the instantaneous value of the AC voltage Vi, the instantaneous value of the DC voltage VD of the DC line DL, the instantaneous value of the DC voltage VB, the output signal of the current detector CD3, etc. This maintains the inter-terminal voltage VB of the battery B1 at the target DC voltage VBT.
  • the control unit 35 also controls the inverter 32 based on the instantaneous value of the AC voltage VO, the output signal of the current detector CD2, the power failure detection signal ⁇ 26, the signal ⁇ Iss, the fault detection signal ⁇ 36, etc. This maintains the output current of the inverter 32 at the secondary current Iss or 0 A.
  • FIG. 7 is a block diagram showing the configuration of the portion of the control unit 35 that is related to the control of the inverter 32.
  • the control unit 35 includes a current command unit 41, a voltage control unit 42, a current control unit 43, and a PWM (Pulse Width Modulation) control unit 44.
  • PWM Pulse Width Modulation
  • the current command unit 41 generates a current command value Ic1 based on the power failure detection signal ⁇ 26, the selection signal SE1, and the signal ⁇ Iss provided by the bypass module 22 (FIG. 4).
  • the selection signal SE1 is at the "L" level, which is the non-selection level, the current command value Ic1 is set to a value corresponding to 0 A, regardless of the power failure detection signal ⁇ 26.
  • the current command value Ic1 is set to a value corresponding to 0 A.
  • the current command value Ic1 is set to a value according to the sub-shared current Iss indicated by the signal ⁇ Iss.
  • the voltage control unit 42 finds the deviation between the current command value Ic1 from the current command unit 41 and the detection value Io1 of the current detector CD2 (the output current of the power module U1), and generates a voltage command value Vc so that the deviation is eliminated.
  • the current control unit 43 finds the deviation between the output voltage VO and the voltage command value Vc, and generates a current command value Ic so that the deviation is eliminated.
  • the PWM control unit 44 When the fault detection signal ⁇ 36 is at the inactivation level "L”, the PWM control unit 44 operates in synchronization with the AC voltage VO at the output terminal T7, generates a PWM signal according to the current command value Ic, and controls the inverter 32 with the PWM signal. When the fault detection signal ⁇ 36 is at the activation level "H”, the PWM control unit 44 stops the operation of the inverter 32.
  • the inverter 32 when the bypass AC power supply 6 is healthy, the inverter 32 outputs a counter voltage VC whose value corresponds to the output voltage VO of the other power modules P2 to PM, outputs 0 A, and is in a standby state in which no current is exchanged with the other power modules P2 to PM or the load 8.
  • the inverter 32 When the corresponding selection signal SE1 is at the "H" level, which is the selection level, if a power outage occurs in the bypass AC power supply 6, the inverter 32 outputs the secondary shared current Iss. At this time, the inverter 32 has already been started and is in a standby state, so when the current command value Ic1 is increased, the output current of the inverter 32 increases quickly and smoothly.
  • the bypass AC power supply 6 When the corresponding selection signal SE1 is at the non-selection level "L", the bypass AC power supply 6 outputs 0 A and is maintained in standby mode regardless of whether it is healthy or not.
  • each power module P (FIG. 6) of each uninterruptible power supply U, the battery B is charged by the converter 31 and bidirectional chopper 33.
  • the inverter 32 is controlled by the control unit 35 (FIGS. 6 and 7) and is placed in a standby state in which it outputs the counter voltage VC without outputting any current.
  • the load current IL is detected by the current detector 2 ( Figure 1), and the control device 5 ( Figure 2) calculates the shared current Is of each uninterruptible power supply U based on the detected value, and a signal ⁇ Is indicating the shared current Is is sent to the control unit 28 ( Figure 4) of each uninterruptible power supply U.
  • the control unit 28 selects the number m of power modules P required to efficiently supply the shared current Is indicated by the signal ⁇ Is, and determines the sub-shared current Iss that the selected power modules P should supply to the load 8.
  • the N semiconductor switches 23 are turned off, and the bypass AC power supply 6 is instantly disconnected from the load 8.
  • the sub-shared current Iss is supplied to the load 8 from each of the selected m power modules P of each uninterruptible power supply U, and the operation of the load 8 continues.
  • the N semiconductor switches 23 included in the N uninterruptible power supplies U1 to UN (Fig. 1) are turned on, and in each uninterruptible power supply U, AC power is supplied from the bypass AC power supply 6 to the load 8 via the reactor 21 and semiconductor switch 23, and each power module P is returned to a standby state.
  • FIG. 8 is a circuit block diagram showing the main parts of an uninterruptible power supply system that is a comparative example of this embodiment, and is a diagram to be compared with FIG. 4.
  • the comparative example differs from this embodiment in that the reactor 21 is removed, and one terminal of the semiconductor switch 23 is directly connected to the bypass terminal T1.
  • FIG. 9 is a circuit block diagram for explaining the bypass ECO power supply mode of an uninterruptible power supply system serving as a comparative example.
  • N semiconductor switches 23 are turned on, and a current IL is supplied from the bypass AC power supply 6 to the load 8 via the parallel connection of N semiconductor switches 23.
  • the sum of I1 to IN is IL.
  • the threshold voltages Vt of the N semiconductor switches 23 are the same, the load current IL is evenly distributed to the N semiconductor switches 23, and a current IL/N that is 1/N of the load current IL flows through each semiconductor switch 23.
  • the threshold voltages Vt of the N semiconductor switches 23 vary within a range of about 10 to 30% from the rated value Vtc. For this reason, the values of the currents I1 to IN flowing through the N semiconductor switches 23 in the bypass ECO power supply mode do not become a constant value IL/N, but vary over a large range.
  • FIG. 10 is a diagram illustrating the VI characteristics of semiconductor switches 23 in a comparative example.
  • curve A shows the VI characteristics of a semiconductor switch 23 having a rated threshold voltage Vtc.
  • Curve B shows the VI characteristics of a semiconductor switch 23 having the smallest threshold voltage Vt1 among the N semiconductor switches 23.
  • Curve C shows the VI characteristics of a semiconductor switch 23 having the largest threshold voltage Vt2 among the N semiconductor switches 23.
  • FIG. 11 is a circuit block diagram for explaining the bypass ECO power supply mode of the uninterruptible power supply system according to this embodiment.
  • N semiconductor switches 23 included in N uninterruptible power supplies U1 to UN are turned on, and AC power is supplied from the bypass AC power source 6 to the load 8 via the parallel connection of the N uninterruptible power supplies U1 to UN.
  • each uninterruptible power supply U includes a series connection of a reactor 21 and a semiconductor switch 23.
  • FIG. 12 is a diagram illustrating the V-I characteristics of reactor 21.
  • the current I flowing through reactor 21 increases in proportion to the voltage V.
  • Reactor 21 is an electric wire wound into a coil, and the impedance of each reactor 21 is adjustable.
  • the threshold voltage Vt of semiconductor switch 23 cannot be adjusted after semiconductor switch 23 is manufactured. For this reason, the characteristic variation of reactor 21 is sufficiently small compared to the variation of threshold voltage Vt of semiconductor switch 23.
  • FIG. 13 is a diagram illustrating the VI characteristics of a series connection of reactor 21 and semiconductor switch 23 in this embodiment. Curves D, E, and F are obtained by adding the VI characteristics of reactor 21 to curves A, B, and C, respectively.
  • each uninterruptible power supply U includes a reactor 21 and a semiconductor switch 23 connected in series between the bypass AC power supply 6 and the load 8, so that when each semiconductor switch 23 is turned on, the load current IL is shunted to a series connection of N reactors 21 and semiconductor switches 23. Therefore, compared to a case where there is no reactor 21, the variation in the magnitude of the currents I1 to IN flowing through the N semiconductor switches 23 can be suppressed to a small value, and the semiconductor switches 23 can be made smaller and less expensive.

Landscapes

  • Business, Economics & Management (AREA)
  • Emergency Management (AREA)
  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Stand-By Power Supply Arrangements (AREA)

Abstract

In this uninterruptible power supply system (1), each uninterruptible power supply device (U) includes a reactor (21) and a semiconductor switch (23) which are connected in series between a bypass AC power supply (6) and a load (8). When turning on each semiconductor switch, load current (IL) is shunted to the series connection bodies of the N reactors and semiconductor switches. Accordingly, in comparison with a case without the reactors, it is possible to suppress and reduce variation in the magnitudes of currents (I1 to IN) flowing through the N semiconductor switches, thereby enabling reduction in the size of the semiconductor switch and reduction in cost.

Description

無停電電源システムUninterruptible Power System
　本開示は、無停電電源システムに関し、特に、負荷に対して並列接続される複数の無停電電源装置を備えた無停電電源システムに関する。 This disclosure relates to an uninterruptible power supply system, and in particular to an uninterruptible power supply system having multiple uninterruptible power supply devices connected in parallel to a load.
　たとえば国際公開２０１７－００９９９８号（特許文献１）には、交流電源と負荷の間に並列接続されるバイパススイッチ、小型半導体スイッチ、および電力変換器を備えた無停電電源装置が開示されている。電力変換器は、交流電源から供給される交流電力を直流電力に変換するコンバータと、直流電力を交流電力に変換して負荷に供給するインバータとを含む。 For example, International Publication No. 2017-009998 (Patent Document 1) discloses an uninterruptible power supply including a bypass switch, a small semiconductor switch, and a power converter connected in parallel between an AC power source and a load. The power converter includes a converter that converts AC power supplied from the AC power source into DC power, and an inverter that converts the DC power into AC power and supplies it to the load.
　交流電源の健全時には、インバータ給電モードが実行され、バイパススイッチおよび半導体スイッチがオフされる。また、コンバータは、交流電源からの交流電力を直流電力に変換する。この直流電力は、バッテリに蓄えられるとともにインバータに与えられる。インバータは、直流電力を交流電力に変換して負荷に供給する。 When the AC power supply is healthy, the inverter power supply mode is executed and the bypass switch and semiconductor switch are turned off. The converter also converts AC power from the AC power supply into DC power. This DC power is stored in the battery and is also provided to the inverter. The inverter converts the DC power into AC power and supplies it to the load.
　インバータが故障した場合には、バイパス給電モードが実行され、電力変換器の運転が停止されるとともに、バイパススイッチおよび半導体スイッチがオンされる。電流による半導体スイッチの過熱を防止するため、半導体スイッチは所定時間経過後にオフされる。交流電源からバイパススイッチを介して負荷に交流電力が供給される。 If the inverter fails, the bypass power supply mode is executed, the operation of the power converter is stopped, and the bypass switch and semiconductor switch are turned on. To prevent the semiconductor switch from overheating due to current, the semiconductor switch is turned off after a specified time has elapsed. AC power is supplied to the load from the AC power source via the bypass switch.
　交流電源の停電が発生した場合には、バッテリ給電モードが実行され、コンバータの運転が停止されるとともに、インバータは、バッテリの直流電力を交流電力に変換して負荷に供給する。したがって、交流電源の停電が発生した場合でも、バッテリに直流電力が蓄えられている期間は、負荷の運転を継続することができる。 If a power outage occurs in the AC power supply, the battery power supply mode is activated, the converter operation is stopped, and the inverter converts the DC power of the battery into AC power and supplies it to the load. Therefore, even if a power outage occurs in the AC power supply, the load can continue to operate as long as DC power is stored in the battery.
国際公開２０１７／００９９９８号International Publication No. 2017/009998
　しかし、このような無停電電源装置では、主に電力変換器で損失が発生し、効率が９０～９６％程度と低いという問題がある。この対策として、バイパスＥＣＯ給電モードを有する無停電電源装置が注目されている。この無停電電源装置は、交流電源と負荷の間に並列接続される大型半導体スイッチおよび電力変換器を備える。 However, such uninterruptible power supplies have the problem that losses occur mainly in the power converter, resulting in low efficiency of around 90-96%. As a solution to this problem, uninterruptible power supplies with a bypass ECO power supply mode have attracted attention. These uninterruptible power supplies are equipped with a large semiconductor switch and a power converter that are connected in parallel between the AC power supply and the load.
　交流電源の健全時には、バイパスＥＣＯ給電モードが実行され、半導体スイッチがオンされ、交流電源からの交流電力が半導体スイッチを介して負荷に供給される。交流電源の停電が発生した場合には、バッテリ給電モードが実行され、半導体スイッチがオフされ、電力変換器に含まれるインバータがバッテリの直流電力を交流電力に変換して負荷に供給する。この無停電電源装置では、主に半導体スイッチで損失が発生するが、半導体スイッチの損失は電力変換器の損失よりも小さいので、９９％と高い効率が得られる。 When the AC power supply is healthy, the bypass ECO power supply mode is executed, the semiconductor switch is turned on, and AC power from the AC power supply is supplied to the load via the semiconductor switch. In the event of a power outage in the AC power supply, the battery power supply mode is executed, the semiconductor switch is turned off, and the inverter included in the power converter converts the battery's DC power to AC power and supplies it to the load. In this uninterruptible power supply, losses occur mainly in the semiconductor switch, but because the losses in the semiconductor switch are smaller than the losses in the power converter, a high efficiency of 99% can be achieved.
　また、交流電源と負荷の間に複数の無停電電源装置を並列接続することにより、大容量の負荷を運転することが可能となる。各無停電電源装置がバイパスＥＣＯ給電モードを実行する場合、交流電源と負荷の間に複数の半導体スイッチが並列接続されることとなり、負荷電流が複数の半導体スイッチに分流される。 In addition, by connecting multiple uninterruptible power supplies in parallel between the AC power supply and the load, it becomes possible to operate a large-capacity load. When each uninterruptible power supply operates in the bypass ECO power supply mode, multiple semiconductor switches are connected in parallel between the AC power supply and the load, and the load current is divided among the multiple semiconductor switches.
　この場合、複数の半導体スイッチのしきい値電圧のばらつきに起因して複数の半導体スイッチに流れる電流の大きさがばらつき、しきい値電圧が小さな半導体スイッチに大きな電流が流れる恐れがある。このため、大電流を安定に流すことが可能な大型で高価格の半導体スイッチを使用する必要があり、システムの大型化、コスト高を招くという問題がある。 In this case, there is a risk that the magnitude of the current flowing through the multiple semiconductor switches will vary due to variations in the threshold voltages of the multiple semiconductor switches, causing a large current to flow through a semiconductor switch with a small threshold voltage. This necessitates the use of large, expensive semiconductor switches that are capable of stably passing a large current, resulting in problems such as an increase in the size of the system and increased costs.
　それゆえに、本開示の主たる目的は、半導体スイッチの小型化、低コスト化を図ることが可能な無停電電源システムを提供することである。 Therefore, the primary objective of this disclosure is to provide an uninterruptible power supply system that enables miniaturization and cost reduction of semiconductor switches.
　本開示の無停電電源システムは、負荷に対して並列接続される複数の無停電電源装置を備えたものである。各無停電電源装置は、第１の交流電源の健全時にオンにされ、第１の交流電源の停電時にオフされる半導体スイッチと、第１の交流電源と負荷の間に半導体スイッチと直列接続されるリアクトルと、第１の交流電源の停電時に、直流電源から供給される直流電力を交流電力に変換して負荷に供給する電力変換器とを含む。 The uninterruptible power supply system disclosed herein includes a plurality of uninterruptible power supply devices connected in parallel to a load. Each uninterruptible power supply device includes a semiconductor switch that is turned on when the first AC power supply is healthy and turned off when the first AC power supply is interrupted, a reactor that is connected in series with the semiconductor switch between the first AC power supply and the load, and a power converter that converts DC power supplied from a DC power supply into AC power and supplies it to the load when the first AC power supply is interrupted.
　本開示の無停電電源システムでは、複数の無停電電源装置の各々が第１の交流電源と負荷の間に直列接続される半導体スイッチおよびリアクトルを含むので、各半導体スイッチをオンすると、負荷電流は複数の半導体スイッチおよびリアクトルの直列接続体に分流される。したがって、リアクトルがない場合に比べ、複数の半導体スイッチに流れる電流の大きさのばらつきを小さく抑制することができ、半導体スイッチの小型化、低コスト化を図ることができる。 In the uninterruptible power supply system disclosed herein, each of the multiple uninterruptible power supply devices includes a semiconductor switch and a reactor connected in series between the first AC power supply and the load, so that when each semiconductor switch is turned on, the load current is diverted to the series connection of the multiple semiconductor switches and reactors. Therefore, compared to a case where there is no reactor, the variation in the magnitude of the current flowing through the multiple semiconductor switches can be reduced, and the semiconductor switches can be made smaller and less expensive.
本開示の一実施の形態に従う無停電電源システムの構成を示す回路ブロック図である。1 is a circuit block diagram showing a configuration of an uninterruptible power supply system according to an embodiment of the present disclosure. 図１に示す制御装置の構成を示すブロック図である。FIG. 2 is a block diagram showing a configuration of a control device shown in FIG. 1 . 図１に示す無停電電源装置の構成を示す回路ブロック図である。2 is a circuit block diagram showing a configuration of the uninterruptible power supply device shown in FIG. 1. 図３に示すバイパスモジュールの構成を示す回路ブロック図である。FIG. 4 is a circuit block diagram showing a configuration of the bypass module shown in FIG. 3 . 図４に示す記憶部に格納されたテーブルを示す図である。FIG. 5 is a diagram showing a table stored in a storage unit shown in FIG. 4 . 図３に示すパワーモジュールの構成を示す回路ブロック図である。FIG. 4 is a circuit block diagram showing a configuration of the power module shown in FIG. 3 . 図６に示す制御部のうちのインバータの制御に関連する部分の構成を示すブロック図である。7 is a block diagram showing a configuration of a portion of the control unit shown in FIG. 6 that is related to inverter control. 実施の形態の比較例となる無停電電源システムの要部を示す回路ブロック図である。1 is a circuit block diagram showing a main part of an uninterruptible power supply system serving as a comparative example of an embodiment. 比較例におけるバイパスＥＣＯ給電モードを説明するための回路ブロック図である。FIG. 11 is a circuit block diagram for explaining a bypass ECO power supply mode in a comparative example. 図９に示す半導体スイッチのＶ－Ｉ特性を例示する図である。FIG. 10 is a diagram illustrating the VI characteristics of the semiconductor switch shown in FIG. 実施の形態におけるバイパスＥＣＯ給電モードを説明するための回路ブロック図である。FIG. 4 is a circuit block diagram for explaining a bypass ECO power supply mode in the embodiment. 図１１に示すリアクトルのＶ－Ｉ特性を例示する図である。12 is a diagram illustrating the VI characteristics of the reactor shown in FIG. 11. 図１１に示すリアクトルおよび半導体スイッチの直列接続体のＶ－Ｉ特性を例示する図である。12 is a diagram illustrating an example of a VI characteristic of a series connection of the reactor and the semiconductor switch shown in FIG. 11.
　図１は、本開示の一実施の形態に従う無停電電源システム１の構成を示す回路ブロック図である。図１において、この無停電電源システム１は、Ｎ台の無停電電源装置（ＵＰＳ）Ｕ１～ＵＮ、Ｎ個のバッテリＢ１～ＢＮ、電流検出器２、通信線３、操作部４、および制御装置５を備える。Ｎは、２以上の整数である。無停電電源装置Ｕ１～ＵＮを総称して代表的に無停電電源装置Ｕと称する場合がある。また、バッテリＢ１～ＢＮを総称して代表的にバッテリＢと称する場合がある。 FIG. 1 is a circuit block diagram showing the configuration of an uninterruptible power supply system 1 according to one embodiment of the present disclosure. In FIG. 1, the uninterruptible power supply system 1 comprises N uninterruptible power supplies (UPS) U1-UN, N batteries B1-BN, a current detector 2, a communication line 3, an operation unit 4, and a control device 5. N is an integer equal to or greater than 2. The uninterruptible power supplies U1-UN may be collectively and representatively referred to as uninterruptible power supply U. Furthermore, the batteries B1-BN may be collectively and representatively referred to as battery B.
　各無停電電源装置Ｕは、バイパス端子Ｔ１、入力端子Ｔ２、直流端子Ｔ３、および出力端子Ｔ４を含む。バイパス端子Ｔ１は、バイパス交流電源６（第１の交流電源）に接続される。入力端子Ｔ２は、交流電源７（第２の交流電源）に接続される。バイパス交流電源６と交流電源７は、別々に設けられていてもよいし、同じものでも構わない。交流電源６，７の各々は、商用交流電源でもよいし、発電機でもよい。交流電源６，７の各々は、無停電電源装置Ｕ１～ＵＮに交流電力を供給する。 Each uninterruptible power supply U includes a bypass terminal T1, an input terminal T2, a DC terminal T3, and an output terminal T4. The bypass terminal T1 is connected to a bypass AC power supply 6 (first AC power supply). The input terminal T2 is connected to an AC power supply 7 (second AC power supply). The bypass AC power supply 6 and the AC power supply 7 may be provided separately or may be the same. Each of the AC power supplies 6, 7 may be a commercial AC power supply or a generator. Each of the AC power supplies 6, 7 supplies AC power to the uninterruptible power supplies U1 to UN.
　無停電電源装置Ｕ１～ＵＮの直流端子Ｔ３は、それぞれバッテリＢ１～ＢＮ（電力貯蔵装置）に接続される。バッテリＢ１～ＢＮの各々は、直流電力を蓄える。バッテリＢ１～ＢＮの代わりに１つの大型バッテリが設けられ、無停電電源装置Ｕ１～ＵＮの直流端子Ｔ３が１つの大型バッテリに接続されていても構わない。また、バッテリＢの代わりにコンデンサが設けられていても構わない。 The DC terminals T3 of the uninterruptible power supplies U1 to UN are connected to batteries B1 to BN (power storage devices), respectively. Each of the batteries B1 to BN stores DC power. A single large battery may be provided in place of the batteries B1 to BN, and the DC terminals T3 of the uninterruptible power supplies U1 to UN may be connected to the single large battery. Also, a capacitor may be provided in place of the battery B.
　無停電電源装置Ｕ１～ＵＮの出力端子Ｔ４は、ともにノードＮ１に接続され、ノードＮ１は負荷８に接続される。負荷８は、無停電電源システム１から供給される交流電力によって駆動される。 The output terminals T4 of the uninterruptible power supplies U1 to UN are all connected to a node N1, which is connected to a load 8. The load 8 is driven by AC power supplied from the uninterruptible power supply system 1.
　電流検出器２は、ノードＮ１と負荷８の間に流れる電流ＩＬを検出し、検出値を示す信号φＩＬを制御装置５に出力する。また、無停電電源装置Ｕ１～ＵＮおよび制御装置５は、通信線３によって互いに接続されている。無停電電源装置Ｕ１～ＵＮおよび制御装置５は、通信線３を介して種々の信号および情報を授受する。 The current detector 2 detects the current IL flowing between the node N1 and the load 8, and outputs a signal φIL indicating the detected value to the control device 5. The uninterruptible power supplies U1-UN and the control device 5 are also connected to each other by a communication line 3. The uninterruptible power supplies U1-UN and the control device 5 exchange various signals and information via the communication line 3.
　操作部４は、複数のボタン、複数のスイッチ、画像表示部を含む。無停電電源システムの使用者は、操作部４を操作することにより、無停電電源システム１を自動運転させたり、各無停電電源装置Ｕを手動で動作させることができる。操作部４は、使用者によって操作された内容を示す信号および情報を制御装置５に出力する。 The operation unit 4 includes a number of buttons, a number of switches, and an image display unit. By operating the operation unit 4, a user of the uninterruptible power supply system can operate the uninterruptible power supply system 1 automatically or can operate each uninterruptible power supply device U manually. The operation unit 4 outputs signals and information indicating the content of operations performed by the user to the control device 5.
　制御装置５は、操作部４および無停電電源装置Ｕ１～ＵＮからの信号および情報、電流検出器２の出力信号φＩＬ等に基づいて、無停電電源システム１全体を制御する。特に、制御装置５は、電流検出器２の出力信号φＩＬによって示される負荷電流ＩＬ基づいて、各無停電電源装置Ｕの分担電流Ｉｓを求める。分担電流Ｉｓを示す信号は、通信線３を介して各無停電電源装置Ｕに与えられる。 The control device 5 controls the entire uninterruptible power supply system 1 based on signals and information from the operation unit 4 and the uninterruptible power supplies U1 to UN, the output signal φIL of the current detector 2, etc. In particular, the control device 5 determines the shared current Is of each uninterruptible power supply U based on the load current IL indicated by the output signal φIL of the current detector 2. A signal indicating the shared current Is is provided to each uninterruptible power supply U via the communication line 3.
　操作部４を用いてシステム１の自動運転が指示された場合において、バイパス交流電源６の健全時には、各無停電電源装置ＵにおいてバイパスＥＣＯ給電モードが実行される。このとき各無停電電源装置Ｕは、バイパス交流電源６からの交流電力を負荷８に供給するとともに、交流電源７からの交流電力を直流電力に変換して対応するバッテリＢを充電する。 When automatic operation of the system 1 is instructed using the operation unit 4, and the bypass AC power supply 6 is healthy, the bypass ECO power supply mode is executed in each uninterruptible power supply device U. At this time, each uninterruptible power supply device U supplies AC power from the bypass AC power supply 6 to the load 8, and converts AC power from the AC power supply 7 to DC power to charge the corresponding battery B.
　バイパスＥＣＯ給電モードの実行中にバイパス交流電源６の停電が発生した場合には、各無停電電源装置Ｕはバッテリ給電モードを実行する。このとき各無停電電源装置Ｕは、対応するバッテリＢの直流電力を交流電力に変換し、制御装置５によって求められる分担電流Ｉｓを負荷８に供給する。 If a power outage occurs in the bypass AC power supply 6 while the bypass ECO power supply mode is being executed, each uninterruptible power supply device U executes the battery power supply mode. At this time, each uninterruptible power supply device U converts the DC power of the corresponding battery B into AC power and supplies the shared current Is determined by the control device 5 to the load 8.
　図２は、制御装置５の構成を示すブロック図である。図２において、制御装置５は、通信部１１、演算部１２、制御部１３、および報知部１４を含む。通信部１１は、制御部１３と通信線３の間に設けられ、制御部１３と各無停電電源装置Ｕの間で種々の信号および情報を授受する。 FIG. 2 is a block diagram showing the configuration of the control device 5. In FIG. 2, the control device 5 includes a communication unit 11, a calculation unit 12, a control unit 13, and a notification unit 14. The communication unit 11 is provided between the control unit 13 and the communication line 3, and transmits and receives various signals and information between the control unit 13 and each uninterruptible power supply device U.
　制御部１３は、操作部４および無停電電源装置Ｕからの信号に基づいて、運転可能な無停電電源装置Ｕの台数ｎを検出し、その台数ｎを示す信号を演算部１２に与える。ｎは、１以上でＮ以下の整数である。 The control unit 13 detects the number n of operable uninterruptible power supplies U based on signals from the operation unit 4 and the uninterruptible power supplies U, and provides a signal indicating the number n to the calculation unit 12. n is an integer greater than or equal to 1 and less than or equal to N.
　演算部１２は、電流検出器２の出力信号φＩＬによって示される負荷電流ＩＬと、制御部１３からの信号によって示される無停電電源装置Ｕの台数ｎとに基づいて、各無停電電源装置Ｕがバッテリ給電モード時に負荷８に供給すべき分担電流Ｉｓを求め、分担電流Ｉｓを示す信号を制御部１３に与える。たとえば、Ｉｓ＝ＩＬ／ｎである。 The calculation unit 12 calculates the shared current Is that each uninterruptible power supply U should supply to the load 8 in battery power supply mode based on the load current IL indicated by the output signal φIL of the current detector 2 and the number n of uninterruptible power supplies U indicated by a signal from the control unit 13, and provides a signal indicating the shared current Is to the control unit 13. For example, Is = IL/n.
　制御部１３は、分担電流Ｉｓを示す信号φＩｓを通信部１１および通信線３を介して各無停電電源装置Ｕに出力する。また、制御部１３は、操作部４の出力信号に従って、種々の信号および情報を通信部１１および通信線３を介して各無停電電源装置Ｕに出力する。 The control unit 13 outputs a signal φIs indicating the shared current Is to each uninterruptible power supply U via the communication unit 11 and the communication line 3. The control unit 13 also outputs various signals and information to each uninterruptible power supply U via the communication unit 11 and the communication line 3 in accordance with the output signal of the operation unit 4.
　また、制御部１３は、故障した無停電電源装置Ｕから通信線３および通信部１１を介して与えられる故障検出信号を報知部１４に与える。報知部１４は、無停電電源装置Ｕの一部が故障した旨を音、光、画像などを使用して無停電電源システムの使用者に報知する。使用者は、故障した無停電電源装置Ｕを修理するか、新品と交換する。 The control unit 13 also provides a failure detection signal provided from the failed uninterruptible power supply U via the communication line 3 and the communication unit 11 to the notification unit 14. The notification unit 14 notifies the user of the uninterruptible power supply system that a part of the uninterruptible power supply U has failed using sound, light, images, etc. The user then repairs the failed uninterruptible power supply U or replaces it with a new one.
　図３は、無停電電源装置Ｕ１の構成を示す回路ブロック図である。図３において、無停電電源装置Ｕ１は、バイパススイッチ２０、リアクトル２１、バイパスモジュール２２、およびＭ個のパワーモジュールＰ１～ＰＭを含む。Ｍは、２以上の整数である。パワーモジュールＰ１～ＰＭを総称して代表的にパワーモジュールＰと称する場合がある。Ｍ個のパワーモジュールＰ１～ＰＭは、「電力変換器」の一実施例を構成する。他の無停電電源装置Ｕ２～ＵＮの各々は、無停電電源装置Ｕ１と同様の構成である。 FIG. 3 is a circuit block diagram showing the configuration of the uninterruptible power supply U1. In FIG. 3, the uninterruptible power supply U1 includes a bypass switch 20, a reactor 21, a bypass module 22, and M power modules P1 to PM, where M is an integer equal to or greater than 2. The power modules P1 to PM may be collectively and representatively referred to as a power module P. The M power modules P1 to PM form one embodiment of a "power converter." Each of the other uninterruptible power supplies U2 to UN has a similar configuration to the uninterruptible power supply U1.
　バイパススイッチ２０は、機械スイッチであり、バイパス端子Ｔ１および出力端子Ｔ４間に接続される。バイパススイッチ２０は、操作部４が操作されてバイパス給電モードが選択された場合に、制御装置５によってオンされる。バイパス給電モード時には、Ｎ個の無停電電源装置Ｕ１～ＵＮに含まれるＮ個のバイパススイッチ２０がオンされ、バイパス交流電源６からＮ個のバイパススイッチ２０の並列接続体を介して負荷８に負荷電流ＩＬが供給される。このとき、バイパススイッチ２０の容量は十分に大きいので、各バイパススイッチ２０には負荷電流ＩＬの１／Ｎの電流が流れる。 The bypass switch 20 is a mechanical switch, and is connected between the bypass terminal T1 and the output terminal T4. The bypass switch 20 is turned on by the control device 5 when the operation unit 4 is operated to select the bypass power supply mode. In the bypass power supply mode, the N bypass switches 20 included in the N uninterruptible power supplies U1 to UN are turned on, and a load current IL is supplied from the bypass AC power supply 6 to the load 8 via the parallel connection of the N bypass switches 20. At this time, the capacity of the bypass switches 20 is sufficiently large, so that a current of 1/N of the load current IL flows through each bypass switch 20.
　リアクトル２１は、バイパス端子Ｔ１と、バイパスモジュール２２の一方端子２２ａとの間に接続される。バイパスモジュール２２の他方端子２２ｂは、出力端子Ｔ４に接続される。リアクトル２１は、バイパスモジュール２２の他方端子２２ｂと、出力端子Ｔ４との間に接続されていても構わない。この場合は、バイパスモジュール２２の一方端子２２ａは、バイパス端子Ｔ１に直接接続される。 The reactor 21 is connected between the bypass terminal T1 and one terminal 22a of the bypass module 22. The other terminal 22b of the bypass module 22 is connected to the output terminal T4. The reactor 21 may be connected between the other terminal 22b of the bypass module 22 and the output terminal T4. In this case, the one terminal 22a of the bypass module 22 is directly connected to the bypass terminal T1.
　図４は、バイパスモジュール２２の構成を示す回路ブロック図である。図４において、バイパスモジュール２２は、半導体スイッチ２３、停電検出部２６、通信部２７、制御部２８、および記憶部２９を含む。半導体スイッチ２３は、互いに逆並列に接続された一対のサイリスタ２４，２５を含む。 FIG. 4 is a circuit block diagram showing the configuration of the bypass module 22. In FIG. 4, the bypass module 22 includes a semiconductor switch 23, a power outage detection unit 26, a communication unit 27, a control unit 28, and a memory unit 29. The semiconductor switch 23 includes a pair of thyristors 24, 25 connected in antiparallel to each other.
　サイリスタ２４のアノードおよびカソードは、バイパスモジュール２２の端子２２ａ，２２ｂにそれぞれ接続される。サイリスタ２５のアノードおよびカソードは、バイパスモジュール２２の端子２２ｂ，２２ａにそれぞれ接続される。なお、半導体スイッチ２３は、サイリスタ２４，２５以外の半導体素子（たとえばトランジスタ、ダイオード等）で構成されていても構わない。 The anode and cathode of the thyristor 24 are connected to the terminals 22a and 22b, respectively, of the bypass module 22. The anode and cathode of the thyristor 25 are connected to the terminals 22b and 22a, respectively, of the bypass module 22. Note that the semiconductor switch 23 may be composed of semiconductor elements other than the thyristors 24 and 25 (e.g., transistors, diodes, etc.).
　半導体スイッチ２３は、制御部２８によって制御され、バイパスＥＣＯ給電モード時にオンされる。半導体スイッチ２３がオンされると、バイパス交流電源６からリアクトル２１および半導体スイッチ２３を介して負荷８に交流電力が供給される。 The semiconductor switch 23 is controlled by the control unit 28 and is turned on in the bypass ECO power supply mode. When the semiconductor switch 23 is turned on, AC power is supplied from the bypass AC power supply 6 to the load 8 via the reactor 21 and the semiconductor switch 23.
　無停電電源システム１全体としては、Ｎ個の半導体スイッチ２３がオンされ、バイパス交流電源６からＮ個のリアクトル２１および半導体スイッチ２３の直列接続体を介して負荷８に負荷電流ＩＬが供給される。 In the uninterruptible power supply system 1 as a whole, N semiconductor switches 23 are turned on, and a load current IL is supplied from the bypass AC power supply 6 to the load 8 via a series connection of N reactors 21 and semiconductor switches 23.
　リアクトル２１は、このときにＮ個の半導体スイッチ２３に流れる電流の大きさのばらつきを小さく抑制するために設けられている。これについては、後述する。バイパス交流電源６の停電が発生すると、半導体スイッチ２３がオフされ、バイパス交流電源６と負荷８との間が瞬時に遮断される。 The reactor 21 is provided to reduce the variation in the magnitude of the current flowing through the N semiconductor switches 23 at this time. This will be described later. When a power outage occurs in the bypass AC power supply 6, the semiconductor switch 23 is turned off, and the bypass AC power supply 6 is instantly disconnected from the load 8.
　停電検出部２６は、バイパス端子Ｔ１に現れる交流電圧ＶＩ（すなわちバイパス交流電源６から供給される交流電圧ＶＩ）の瞬時値を検出し、その検出値に基づいてバイパス交流電源６の停電が発生しているか否かを判別し、判別結果を示す停電検出信号φ２６を出力する。 The power outage detection unit 26 detects the instantaneous value of the AC voltage VI (i.e., the AC voltage VI supplied from the bypass AC power supply 6) that appears at the bypass terminal T1, determines whether or not a power outage has occurred in the bypass AC power supply 6 based on the detected value, and outputs a power outage detection signal φ26 that indicates the determination result.
　たとえば、停電検出部２６は、交流電圧ＶＩが下限値よりも高い場合には、バイパス交流電源６から交流電圧ＶＩが正常に供給されており、バイパス交流電源６は健全であると判別する。また停電検出部２６は、交流電圧ＶＩが下限値よりも低い場合には、バイパス交流電源６から交流電圧ＶＩが正常に供給されておらず、バイパス交流電源６の停電が発生していると判別する。 For example, when the AC voltage VI is higher than the lower limit, the power outage detection unit 26 determines that the AC voltage VI is being supplied normally from the bypass AC power supply 6 and that the bypass AC power supply 6 is healthy. When the AC voltage VI is lower than the lower limit, the power outage detection unit 26 determines that the AC voltage VI is not being supplied normally from the bypass AC power supply 6 and that a power outage of the bypass AC power supply 6 has occurred.
　バイパス交流電源６が健全である場合には、停電検出信号φ２６は非活性化レベルの「Ｈ」レベルにされる。バイパス交流電源６の停電が発生している場合には、停電検出信号φ２６は活性化レベルの「Ｌ」レベルにされる。 When the bypass AC power supply 6 is healthy, the power outage detection signal φ26 is set to the inactive "H" level. When a power outage occurs in the bypass AC power supply 6, the power outage detection signal φ26 is set to the active "L" level.
　通信部２７は、通信線３を介して無停電電源装置Ｕ１内のパワーモジュールＰ１～ＰＭ、他の無停電電源装置Ｕ２～ＵＭ、および制御装置５に接続されており、それらと制御部２８との間で種々の信号および情報を授受する。 The communication unit 27 is connected to the power modules P1-PM in the uninterruptible power supply U1, the other uninterruptible power supplies U2-UM, and the control device 5 via the communication line 3, and transmits and receives various signals and information between them and the control unit 28.
　制御部２８は、制御装置５から通信線３および通信部２７を介してバイパスＥＣＯ給電モードの実行が指令され、かつ停電検出信号φ２６が非活性化レベルの「Ｈ」レベルである場合には、半導体スイッチ２３をオンさせる。 The control unit 28 turns on the semiconductor switch 23 when the control device 5 issues a command to execute the bypass ECO power supply mode via the communication line 3 and the communication unit 27, and the power failure detection signal φ26 is at the inactivation level of "H".
　また制御部２８は、停電検出信号φ２６が活性化レベルの「Ｌ」レベルにされた場合には、半導体スイッチ２３をオフさせる。停電検出信号φ２６は、制御部２８、通信部２７、および通信線３を介してパワーモジュールＰ１～ＰＭに与えられる。 In addition, when the power failure detection signal φ26 is set to the "L" level, which is the activation level, the control unit 28 turns off the semiconductor switch 23. The power failure detection signal φ26 is provided to the power modules P1 to PM via the control unit 28, the communication unit 27, and the communication line 3.
　また制御部２８は、制御装置５（図５）から通信線３および通信部２７を介して与えられる信号φＩｓによって示される分担電流Ｉｓを効率よく供給するために必要な台数ｍのパワーモジュールＰを選択し、選択結果を示す信号ＳＥ１～ＳＥＭを出力する。ｍは、１以上でＭ以下の整数である。選択信号ＳＥ１～ＳＥＭを代表的に総称して選択信号ＳＥと称する場合がある。 The control unit 28 also selects the number m of power modules P required to efficiently supply the shared current Is indicated by the signal φIs provided from the control device 5 (FIG. 5) via the communication line 3 and the communication unit 27, and outputs signals SE1 to SEM indicating the selection result. m is an integer greater than or equal to 1 and less than or equal to M. The selection signals SE1 to SEM may be collectively referred to as the selection signal SE.
　ｍ台のパワーモジュールＰを選択するのは、全パワーモジュールＰ１～ＰＭを選択すると、各パワーモジュールＰの出力電流が小さくなり過ぎて、各パワーモジュールＰの効率が低下するからである。 The reason for selecting m power modules P is that if all power modules P1 to PM were selected, the output current of each power module P would be too small, reducing the efficiency of each power module P.
　選択信号ＳＥ１～ＳＥＭは、それぞれパワーモジュールＰ１～ＰＭに対応している。あるパワーモジュールＰが選択された場合には、そのパワーモジュールＰに対応する選択信号ＳＥは選択レベルの「Ｈ」レベルにされる。あるパワーモジュールＰが選択されていない場合には、そのパワーモジュールＰに対応する選択信号ＳＥは非選択レベルの「Ｌ」レベルにされる。 The selection signals SE1 to SEM correspond to the power modules P1 to PM, respectively. When a power module P is selected, the selection signal SE corresponding to that power module P is set to the selection level "H". When a power module P is not selected, the selection signal SE corresponding to that power module P is set to the non-selection level "L".
　制御部２８は、分担電流Ｉｓのｍ分の１の副分担電流Ｉｓｓを求め、その副分担電流Ｉｓｓを示す信号φＩｓｓを各パワーモジュールＰに与える。バイパス交流電源６の停電が発生した場合には、選択されたｍ台のパワーモジュールＰの各々が、分担電流Ｉｓのｍ分の１の副分担電流Ｉｓｓを負荷８に供給する。 The control unit 28 calculates a sub-shared current Iss that is 1/m of the shared current Is, and provides a signal φIss indicating the sub-shared current Iss to each power module P. In the event of a power outage in the bypass AC power supply 6, each of the selected m power modules P supplies a sub-shared current Iss that is 1/m of the shared current Is to the load 8.
　この場合において制御部２８は、バイパス交流電源６の停電が発生する度に、選択するｍ台のパワーモジュールＰの組み合わせを変更する。これは、特定のパワーモジュールＰが繰り返し選択されて、そのパワーモジュールＰが他のパワーモジュールＰよりも早く劣化することを防止するためである。記憶部２９には、ｍ台のパワーモジュールＰの組み合わせを示すテーブルが格納されている。 In this case, the control unit 28 changes the combination of the m power modules P to be selected each time a power outage occurs in the bypass AC power supply 6. This is to prevent a specific power module P from being repeatedly selected and deteriorating faster than other power modules P. The memory unit 29 stores a table showing the combinations of the m power modules P.
　図５は、記憶部２９に格納されたテーブルを示す図である。図５において、このテーブルは、Ｍ＝５でｍ＝３の場合におけるパワーモジュールＰの組み合わせを示している。このテーブルでは、１０個のパターンが示されている。各パターンにおいて、〇印が付されたパワーモジュールＰが選択される。 FIG. 5 is a diagram showing a table stored in the memory unit 29. In FIG. 5, this table shows combinations of power modules P when M=5 and m=3. In this table, 10 patterns are shown. In each pattern, the power module P marked with a circle is selected.
　パターン１では、５台のパワーモジュールＰ１～Ｐ５のうちのパワーモジュールＰ１～Ｐ３が選択される。パターン２では、パワーモジュールＰ１，Ｐ２，Ｐ４が選択される。パターン３では、パワーモジュールＰ１，Ｐ２，Ｐ５が選択される。パターン４では、パワーモジュールＰ１，Ｐ３，Ｐ４が選択される。パターン５では、パワーモジュールＰ１，Ｐ３，Ｐ５が選択される。パターン６では、パワーモジュールＰ１，Ｐ４，Ｐ５が選択される。パターン７では、パワーモジュールＰ２～Ｐ４が選択される。パターン８では、パワーモジュールＰ２，Ｐ３，Ｐ５が選択される。パターン９では、パワーモジュールＰ２，Ｐ４，Ｐ５が選択される。パターン１０では、パワーモジュールＰ３～Ｐ５が選択される。 In pattern 1, power modules P1 to P3 are selected out of the five power modules P1 to P5. In pattern 2, power modules P1, P2, and P4 are selected. In pattern 3, power modules P1, P2, and P5 are selected. In pattern 4, power modules P1, P3, and P4 are selected. In pattern 5, power modules P1, P3, and P5 are selected. In pattern 6, power modules P1, P4, and P5 are selected. In pattern 7, power modules P2 to P4 are selected. In pattern 8, power modules P2, P3, and P5 are selected. In pattern 9, power modules P2, P4, and P5 are selected. In pattern 10, power modules P3 to P5 are selected.
　制御部２８は、１回目はパターン１の３台のパワーモジュールＰ１～Ｐ３を選択し、２～１０回目はそれぞれパターン２からパターン１０の３台のパワーモジュールＰを選択し、１１回目は再びパターン１の３台のパワーモジュールＰ１～Ｐ３を選択する。以下、同様である。 The control unit 28 selects three power modules P1 to P3 of pattern 1 the first time, selects three power modules P of patterns 2 to 10 the second to tenth times, and again selects three power modules P1 to P3 of pattern 1 the eleventh time. This is the same as above.
　Ｍ＝５の場合、記憶部２９にはｍが１，２，３，４である場合の４つのテーブルが格納されている。制御部２８は、ｍの値に応じて４つのテーブルのうちのいずれかのテーブルを選択し、そのテーブルを参照してｍ台のパワーモジュールＰを選択する。ｍ＝５である場合には、制御部２８は常に全部のパワーモジュールＰ１～Ｐ５を選択する。 When M=5, the memory unit 29 stores four tables for m=1, 2, 3, and 4. The control unit 28 selects one of the four tables according to the value of m, and refers to that table to select m power modules P. When m=5, the control unit 28 always selects all power modules P1 to P5.
　再び図３を参照して、各パワーモジュールＰは、入力端子Ｔ５、直流端子Ｔ６、および出力端子Ｔ７を含む。入力端子Ｔ５、直流端子Ｔ６、および出力端子Ｔ７は、それぞれ対応する無停電電源装置Ｕ１の入力端子Ｔ２、直流端子Ｔ３、および出力端子Ｔ４に接続されている。 Referring again to FIG. 3, each power module P includes an input terminal T5, a DC terminal T6, and an output terminal T7. The input terminal T5, DC terminal T6, and output terminal T7 are connected to the input terminal T2, DC terminal T3, and output terminal T4 of the corresponding uninterruptible power supply U1, respectively.
　パワーモジュールＰは、交流電源７の健全時には、交流電源７から供給される交流電力を直流電力に変換して対応するバッテリＢ１に蓄える。交流電源７の停電が発生すると、パワーモジュールＰは、バッテリＢ１の充電を停止する。 When the AC power source 7 is healthy, the power module P converts the AC power supplied from the AC power source 7 into DC power and stores it in the corresponding battery B1. When a power outage occurs in the AC power source 7, the power module P stops charging the battery B1.
　バイパスＥＣＯ給電モード時において停電検出信号φ２６（図４）が非活性化レベルの「Ｈ」レベルである場合には、各パワーモジュールＰは、出力端子Ｔ４に現れる交流電圧ＶＯに対抗するカウンタ電圧ＶＣを出力し、他のパワーモジュールＰおよび負荷８と電流を授受しない待機状態にされる。換言すると、このとき各パワーモジュールＰはカウンタ電圧ＶＣを出力し、０Ａを出力する。 When the power failure detection signal φ26 (FIG. 4) is at the inactive "H" level during bypass ECO power supply mode, each power module P outputs a counter voltage VC that opposes the AC voltage VO appearing at the output terminal T4, and is placed in a standby state in which no current is exchanged with other power modules P or the load 8. In other words, at this time, each power module P outputs the counter voltage VC and outputs 0 A.
　停電検出信号φ２６が活性化レベルの「Ｌ」レベルにされると、パワーモジュールＰ１～ＰＭのうちの制御部２８（図４）によって選択されたｍ台のパワーモジュールＰの各々は、制御部２８からの信号φＩｓｓによって示される副分担電流Ｉｓｓを負荷８に供給する。 When the power failure detection signal φ26 is set to the "L" level, which is the activation level, each of the m power modules P selected by the control unit 28 (FIG. 4) from among the power modules P1 to PM supplies the sub-shared current Iss indicated by the signal φIss from the control unit 28 to the load 8.
　図６は、パワーモジュールＰ１の構成を示す回路ブロック図である。図６において、このパワーモジュールＰ１は、端子Ｔ５～Ｔ７（図３）に加え、ヒューズＦ１～Ｆ３、スイッチＳ１～Ｓ３、コンデンサＣ１～Ｃ３、リアクトルＬ１～Ｌ３、コンバータ３１、直流ラインＤＬ、インバータ３２、双方向チョッパ３３、電流検出器ＣＤ１～ＣＤ３、通信部３４、制御部３５、および故障検出部３６を備える。他のパワーモジュールＰ２～ＰＭの各々は、パワーモジュールＰ１と同様の構成である。 FIG. 6 is a circuit block diagram showing the configuration of power module P1. In FIG. 6, in addition to terminals T5 to T7 (FIG. 3), this power module P1 includes fuses F1 to F3, switches S1 to S3, capacitors C1 to C3, reactors L1 to L3, converter 31, DC line DL, inverter 32, bidirectional chopper 33, current detectors CD1 to CD3, communication unit 34, control unit 35, and fault detection unit 36. Each of the other power modules P2 to PM has the same configuration as power module P1.
　スイッチＳ１の一方端子はヒューズＦ１を介して入力端子Ｔ５に接続され、その他方端子はリアクトルＬ１を介してコンバータ３１の入力ノードに接続される。コンデンサＣ１は、スイッチＳ１の他方端子に接続される。コンバータ３１の出力ノードは、直流ラインＤＬを介してインバータ３２の入力ノードに接続されるとともに、双方向チョッパ３３の一方入出力ノードに接続される。コンデンサＣ３は、直流ラインＤＬに接続される。パワーモジュールＰ１～ＰＮの直流ラインＤＬは、互いに接続されている。 One terminal of the switch S1 is connected to the input terminal T5 via the fuse F1, and the other terminal is connected to the input node of the converter 31 via the reactor L1. The capacitor C1 is connected to the other terminal of the switch S1. The output node of the converter 31 is connected to the input node of the inverter 32 via the DC line DL, and is also connected to one input/output node of the bidirectional chopper 33. The capacitor C3 is connected to the DC line DL. The DC lines DL of the power modules P1 to PN are connected to each other.
　インバータ３２の出力ノードはリアクトルＬ２を介してスイッチＳ２の一方端子に接続され、スイッチＳ２の他方端子はヒューズＦ２を介して出力端子Ｔ７に接続される。コンデンサＣ２は、スイッチＳ２の一方端子に接続される。スイッチＳ３の一方端子はヒューズＦ３を介して直流端子Ｔ６に接続され、その他方端子はリアクトルＬ３を介して双方向チョッパ３３の他方入出力ノードに接続される。 The output node of the inverter 32 is connected to one terminal of a switch S2 via a reactor L2, and the other terminal of the switch S2 is connected to an output terminal T7 via a fuse F2. A capacitor C2 is connected to one terminal of the switch S2. One terminal of the switch S3 is connected to a DC terminal T6 via a fuse F3, and the other terminal is connected to the other input/output node of the bidirectional chopper 33 via a reactor L3.
　ヒューズＦ１は、過電流が流れた場合にブローされ、コンバータ３１などを保護する。スイッチＳ１は、制御部３５によって制御される。交流電源７から交流電圧Ｖｉが正常に供給されている場合（交流電源７の健全時）には、スイッチＳ１はオンされる。交流電源７から交流電圧Ｖｉが正常に供給されていない場合（交流電源７の停電時）には、スイッチＳ１はオフされる。 Fuse F1 is blown when an overcurrent flows, protecting converter 31 and other components. Switch S1 is controlled by control unit 35. When AC voltage Vi is being supplied normally from AC power supply 7 (when AC power supply 7 is functioning properly), switch S1 is turned on. When AC voltage Vi is not being supplied normally from AC power supply 7 (when AC power supply 7 is experiencing a power outage), switch S1 is turned off.
　コンデンサＣ１およびリアクトルＬ１は交流フィルタを構成する。交流フィルタは、ローパスフィルタであり、交流電源７から供給される商用周波数の交流電力を通過させ、コンバータ３１で発生するスイッチング周波数の信号を遮断する。 Capacitor C1 and reactor L1 form an AC filter. The AC filter is a low-pass filter that passes commercial frequency AC power supplied from AC power source 7 and blocks the switching frequency signal generated by converter 31.
　コンバータ３１は、制御部３５によって制御され、交流電源７の健全時には、交流電源７からの交流電力を直流電力に変換し、その直流電力を直流ラインＤＬを介してインバータ３２および双方向チョッパ３３に与える。コンバータ３１は、直流ラインＤＬの直流電圧ＶＤが目標直流電圧ＶＤＴに一致するように、直流電流を直流ラインＤＬに出力する。交流電源７の停電時には、コンバータ３１の運転は停止される。コンデンサＣ１、リアクトルＬ１、およびコンバータ３１は、交流電力を直流電力に変換する「順変換器」の一実施例を構成する。コンデンサＣ３は、直流ラインＤＬの直流電圧ＶＤを平滑化および安定化させる。 The converter 31 is controlled by the control unit 35, and when the AC power supply 7 is healthy, it converts the AC power from the AC power supply 7 into DC power and supplies the DC power to the inverter 32 and the bidirectional chopper 33 via the DC line DL. The converter 31 outputs a DC current to the DC line DL so that the DC voltage VD of the DC line DL matches the target DC voltage VDT. When the AC power supply 7 experiences a power outage, the operation of the converter 31 is stopped. The capacitor C1, the reactor L1, and the converter 31 constitute one embodiment of a "forward converter" that converts AC power into DC power. The capacitor C3 smoothes and stabilizes the DC voltage VD of the DC line DL.
　ヒューズＦ３は、過電流が流れた場合にブローされ、バッテリＢ１、双方向チョッパ３３などを保護する。スイッチＳ３は、パワーモジュールＰ１を使用する場合にオンされ、たとえばバッテリＢ１のメンテナンス時にオフされる。リアクトルＬ３は、ローパスフィルタであり、直流電力を通過させ、双方向チョッパ３３で発生するスイッチング周波数の信号を遮断する。 Fuse F3 is blown in the event of an overcurrent, protecting battery B1, bidirectional chopper 33, etc. Switch S3 is turned on when power module P1 is in use, and turned off, for example, during maintenance of battery B1. Reactor L3 is a low-pass filter that passes DC power and blocks the switching frequency signal generated by bidirectional chopper 33.
　双方向チョッパ３３は、制御部３５によって制御され、交流電源７の健全時にはコンバータ３１によって生成される直流電力をバッテリＢ１に蓄え、バイパス交流電源６の停電時にはバッテリＢ１の直流電力をインバータ３２に供給する。双方向チョッパ３３は、交流電源７の健全時には、バッテリＢ１の端子間電圧ＶＢが目標直流電圧ＶＢＴになるように、バッテリＢ１に直流電流を供給する。双方向チョッパ３３は、バイパス交流電源６の停電時には、直流ラインＤＬの直流電圧ＶＤが目標直流電圧ＶＤＴに一致するように、直流電流を直流ラインＤＬに出力する。 The bidirectional chopper 33 is controlled by the control unit 35, and stores the DC power generated by the converter 31 in the battery B1 when the AC power supply 7 is healthy, and supplies the DC power of the battery B1 to the inverter 32 when the bypass AC power supply 6 fails. When the AC power supply 7 is healthy, the bidirectional chopper 33 supplies a DC current to the battery B1 so that the terminal voltage VB of the battery B1 becomes the target DC voltage VBT. When the bypass AC power supply 6 fails, the bidirectional chopper 33 outputs a DC current to the DC line DL so that the DC voltage VD of the DC line DL becomes equal to the target DC voltage VDT.
　インバータ３２は、制御部３５によって制御される。停電検出信号φ２６（図４）が非活性化レベルの「Ｈ」レベルである場合には、インバータ３２は、出力端子Ｔ７に現れる交流電圧ＶＯに対抗するカウンタ電圧ＶＣを出力し、他のパワーモジュールＰ２～ＰＭおよび負荷８と電流を授受しない待機状態にされる。換言すると、このときインバータ３２はカウンタ電圧ＶＣを出力し、０Ａを出力する。 The inverter 32 is controlled by the control unit 35. When the power failure detection signal φ26 (FIG. 4) is at the inactivation level "H", the inverter 32 outputs a counter voltage VC that opposes the AC voltage VO appearing at the output terminal T7, and is placed in a standby state in which it does not exchange current with the other power modules P2 to PM or the load 8. In other words, at this time the inverter 32 outputs the counter voltage VC and outputs 0 A.
　対応するパワーモジュールＰ１が制御部２８（図４）によって選択されている場合において、停電検出信号φ２６が活性化レベルの「Ｌ」レベルにされた場合には、インバータ３２は、副分担電流Ｉｓｓを負荷８に供給する。 When the corresponding power module P1 is selected by the control unit 28 (Figure 4), if the power failure detection signal φ26 is set to the "L" level, which is the activation level, the inverter 32 supplies the secondary current Iss to the load 8.
　リアクトルＬ２およびコンデンサＣ２は交流フィルタを構成する。交流フィルタは、ローパスフィルタであり、インバータ３２によって生成された商用周波数の交流電力を通過させ、インバータ３２で発生するスイッチング周波数の信号を遮断する。換言すると、交流フィルタは、インバータ３２の出力電圧の波形を正弦波に整形する。インバータ３２、リアクトルＬ２、およびコンデンサＣ２は、直流電力を交流電力に変換する「逆変換器」の一実施例を構成する。 The reactor L2 and the capacitor C2 form an AC filter. The AC filter is a low-pass filter that passes commercial frequency AC power generated by the inverter 32 and blocks signals of the switching frequency generated by the inverter 32. In other words, the AC filter shapes the waveform of the output voltage of the inverter 32 into a sine wave. The inverter 32, the reactor L2, and the capacitor C2 form one embodiment of an "inverter" that converts DC power to AC power.
　スイッチＳ２は、パワーモジュールＰ１を使用する場合にオンされ、インバータ３２が故障した場合およびインバータ３２のメンテナンス時にオフされる。入力端子Ｔ５の交流電圧Ｖｉ（すなわち交流電源７から供給される交流電圧）と、出力端子Ｔ７の交流電圧ＶＯ（すなわち出力電圧）と、直流端子Ｔ６の直流電圧ＶＢ（すなわちバッテリＢ１の端子間電圧）と、直流ラインＤＬの直流電圧ＶＤとは、制御部３５に与えられる。 The switch S2 is turned on when the power module P1 is used, and is turned off when the inverter 32 fails or during maintenance of the inverter 32. The AC voltage Vi at the input terminal T5 (i.e., the AC voltage supplied from the AC power source 7), the AC voltage VO at the output terminal T7 (i.e., the output voltage), the DC voltage VB at the DC terminal T6 (i.e., the voltage between the terminals of the battery B1), and the DC voltage VD of the DC line DL are provided to the control unit 35.
　電流検出器ＣＤ１は、リアクトルＬ１に流れる交流電流（すなわちコンバータ３１の入力電流）の瞬時値を検出し、その検出値を示す信号を制御部３５に与える。電流検出器ＣＤ２は、リアクトルＬ２に流れる交流電流（すなわちインバータ３２の出力電流）の瞬時値を検出し、その検出値を示す信号を制御部３５に与える。電流検出器ＣＤ３は、リアクトルＬ３に流れる直流電流（すなわちバッテリＢ１に流れる直流電流）の瞬時値を検出し、その検出値を示す信号を制御部３５に与える。 Current detector CD1 detects the instantaneous value of the AC current flowing through reactor L1 (i.e., the input current of converter 31) and provides a signal indicating the detected value to control unit 35. Current detector CD2 detects the instantaneous value of the AC current flowing through reactor L2 (i.e., the output current of inverter 32) and provides a signal indicating the detected value to control unit 35. Current detector CD3 detects the instantaneous value of the DC current flowing through reactor L3 (i.e., the DC current flowing through battery B1) and provides a signal indicating the detected value to control unit 35.
　通信部３４は、制御部３５と通信線３の間に設けられ、バイパスモジュール２２、他のパワーモジュールＰ２～ＰＭ、制御装置５との間で種々の信号および情報を授受する。 The communication unit 34 is provided between the control unit 35 and the communication line 3, and transmits and receives various signals and information between the bypass module 22, the other power modules P2 to PM, and the control device 5.
　故障検出部３６は、対応するインバータ３２が正常であるか否かを判別し、判別結果を示す故障検出信号φ３６を出力する。インバータ３２が正常である場合には、故障検出信号φ３６は非活性化レベルの「Ｌ」レベルにされる。インバータ３２が故障している場合には、故障検出信号φ３６は活性化レベルの「Ｈ」レベルにされる。 The fault detection unit 36 determines whether the corresponding inverter 32 is normal or not, and outputs a fault detection signal φ36 indicating the determination result. If the inverter 32 is normal, the fault detection signal φ36 is set to the inactivation level "L" level. If the inverter 32 is faulty, the fault detection signal φ36 is set to the activation level "H" level.
　故障検出信号φ３６は、制御部３５に与えられる。制御部３５は、故障検出信号φ３６は非活性化レベルの「Ｌ」レベルである場合には、インバータ３２を制御する。故障検出信号φ３６は活性化レベルの「Ｈ」レベルである場合には、制御部３５は、インバータ３２の運転を停止させるとともに、スイッチＳ２をオフさせる。 The fault detection signal φ36 is given to the control unit 35. When the fault detection signal φ36 is at the "L" level, which is the inactivation level, the control unit 35 controls the inverter 32. When the fault detection signal φ36 is at the "H" level, which is the activation level, the control unit 35 stops the operation of the inverter 32 and turns off the switch S2.
　また、故障検出信号φ３６は、制御部３５、通信部３４、通信線３、および通信部２７（図４）を介して制御部２８に与えられる。故障検出信号φ３６は活性化レベルの「Ｈ」レベルである場合には、制御部２８は、その故障検出信号φ３６に対応するパワーモジュール（この場合はＰ１）以外のパワーモジュールＰ２～ＰＭからｍ台のパワーモジュールＰを選択する。 Failure detection signal φ36 is also provided to control unit 28 via control unit 35, communication unit 34, communication line 3, and communication unit 27 (FIG. 4). When failure detection signal φ36 is at the "H" level, which is the activation level, control unit 28 selects m power modules P from power modules P2 to PM other than the power module corresponding to that failure detection signal φ36 (P1 in this case).
　制御部３５は、交流電圧Ｖｉ，ＶＯの瞬時値、直流電圧ＶＢ，ＶＤの瞬時値、電流検出器ＣＤ１～ＣＤ３の検出値、故障検出信号φ３６、制御装置５および制御部２８から通信線３および通信部３４を介して供給される種々の信号および情報に基づいて、パワーモジュールＰ１全体を制御する。 The control unit 35 controls the entire power module P1 based on the instantaneous values of the AC voltages Vi, VO, the instantaneous values of the DC voltages VB, VD, the detection values of the current detectors CD1 to CD3, the fault detection signal φ36, and various signals and information supplied from the control device 5 and the control unit 28 via the communication line 3 and the communication unit 34.
　特に、制御部３５は、交流電圧Ｖｉの瞬時値、直流ラインＤＬの直流電圧ＶＤの瞬時値、電流検出器ＣＤ１の検出値などに基づいて、コンバータ３１を制御する。これにより、直流ラインＤＬの直流電圧ＶＤは、目標直流電圧ＶＤＴに維持される。 In particular, the control unit 35 controls the converter 31 based on the instantaneous value of the AC voltage Vi, the instantaneous value of the DC voltage VD of the DC line DL, the detection value of the current detector CD1, etc. As a result, the DC voltage VD of the DC line DL is maintained at the target DC voltage VDT.
　また制御部３５は、交流電圧Ｖｉの瞬時値、直流ラインＤＬの直流電圧ＶＤの瞬時値、直流電圧ＶＢの瞬時値、電流検出器ＣＤ３の出力信号などに基づいて、双方向チョッパ３３を制御する。これにより、バッテリＢ１の端子間電圧ＶＢが目標直流電圧ＶＢＴに維持される。 The control unit 35 also controls the bidirectional chopper 33 based on the instantaneous value of the AC voltage Vi, the instantaneous value of the DC voltage VD of the DC line DL, the instantaneous value of the DC voltage VB, the output signal of the current detector CD3, etc. This maintains the inter-terminal voltage VB of the battery B1 at the target DC voltage VBT.
　また制御部３５は、交流電圧ＶＯの瞬時値、電流検出器ＣＤ２の出力信号、停電検出信号φ２６、信号φＩｓｓ、故障検出信号φ３６などに基づいて、インバータ３２を制御する。これにより、インバータ３２の出力電流が副分担電流Ｉｓｓまたは０Ａに維持される。 The control unit 35 also controls the inverter 32 based on the instantaneous value of the AC voltage VO, the output signal of the current detector CD2, the power failure detection signal φ26, the signal φIss, the fault detection signal φ36, etc. This maintains the output current of the inverter 32 at the secondary current Iss or 0 A.
　図７は、制御部３５のうちのインバータ３２の制御に関連する部分の構成を示すブロック図である。図７において、制御部３５は、電流指令部４１、電圧制御部４２、電流制御部４３、およびＰＷＭ（Pulse　Width　Modulation）制御部４４を含む。 FIG. 7 is a block diagram showing the configuration of the portion of the control unit 35 that is related to the control of the inverter 32. In FIG. 7, the control unit 35 includes a current command unit 41, a voltage control unit 42, a current control unit 43, and a PWM (Pulse Width Modulation) control unit 44.
　電流指令部４１は、バイパスモジュール２２（図４）から与えられる停電検出信号φ２６、選択信号ＳＥ１、および信号φＩｓｓに基づいて、電流指令値Ｉｃ１を生成する。選択信号ＳＥ１が非選択レベルの「Ｌ」レベルである場合には、停電検出信号φ２６に関係なく、電流指令値Ｉｃ１は０Ａに応じた値に設定される。 The current command unit 41 generates a current command value Ic1 based on the power failure detection signal φ26, the selection signal SE1, and the signal φIss provided by the bypass module 22 (FIG. 4). When the selection signal SE1 is at the "L" level, which is the non-selection level, the current command value Ic1 is set to a value corresponding to 0 A, regardless of the power failure detection signal φ26.
　選択信号ＳＥ１が選択レベルの「Ｈ」レベルである場合において、停電検出信号φ２６が非活性化レベルの「Ｈ」レベルである場合（バイパス交流電源６の健全時）には、電流指令値Ｉｃ１は０Ａに応じた値に設定される。 When the selection signal SE1 is at the "H" level of the selection level, and the power failure detection signal φ26 is at the "H" level of the inactivation level (when the bypass AC power supply 6 is healthy), the current command value Ic1 is set to a value corresponding to 0 A.
　選択信号ＳＥ１が選択レベルの「Ｈ」レベルである場合において、停電検出信号φ２６が活性化レベルの「Ｌ」レベルである場合（バイパス交流電源６の停電時）には、電流指令値Ｉｃ１は信号φＩｓｓによって示される副分担電流Ｉｓｓに応じた値に設定される。 When the selection signal SE1 is at the "H" level of the selection level and the power failure detection signal φ26 is at the "L" level of the activation level (when the bypass AC power supply 6 is at a power failure), the current command value Ic1 is set to a value according to the sub-shared current Iss indicated by the signal φIss.
　電圧制御部４２は、電流指令部４１からの電流指令値Ｉｃ１と電流検出器ＣＤ２の検出値Ｉｏ１（パワーモジュールＵ１の出力電流）との偏差を求め、その偏差がなくなるように電圧指令値Ｖｃを生成する。電流制御部４３は、出力電圧ＶＯと電圧指令値Ｖｃの偏差を求め、その偏差がなくなるように電流指令値Ｉｃを生成する。 The voltage control unit 42 finds the deviation between the current command value Ic1 from the current command unit 41 and the detection value Io1 of the current detector CD2 (the output current of the power module U1), and generates a voltage command value Vc so that the deviation is eliminated. The current control unit 43 finds the deviation between the output voltage VO and the voltage command value Vc, and generates a current command value Ic so that the deviation is eliminated.
　ＰＷＭ制御部４４は、故障検出信号φ３６が非活性化レベルの「Ｌ」レベルである場合には、出力端子Ｔ７の交流電圧ＶＯに同期して動作し、電流指令値Ｉｃに従ってＰＷＭ信号を生成し、そのＰＷＭ信号によってインバータ３２を制御する。故障検出信号φ３６が活性化レベルの「Ｈ」レベルである場合には、ＰＷＭ制御部４４は、インバータ３２の運転を停止する。 When the fault detection signal φ36 is at the inactivation level "L", the PWM control unit 44 operates in synchronization with the AC voltage VO at the output terminal T7, generates a PWM signal according to the current command value Ic, and controls the inverter 32 with the PWM signal. When the fault detection signal φ36 is at the activation level "H", the PWM control unit 44 stops the operation of the inverter 32.
　換言すると、バイパス交流電源６の健全時には、インバータ３２は、他のパワーモジュールＰ２～ＰＭの出力電圧ＶＯに応じた値のカウンタ電圧ＶＣを出力するとともに０Ａを出力し、他のパワーモジュールＰ２～ＰＭおよび負荷８と電流を授受しない待機状態にされる。 In other words, when the bypass AC power supply 6 is healthy, the inverter 32 outputs a counter voltage VC whose value corresponds to the output voltage VO of the other power modules P2 to PM, outputs 0 A, and is in a standby state in which no current is exchanged with the other power modules P2 to PM or the load 8.
　対応する選択信号ＳＥ１が選択レベルの「Ｈ」レベルにされている場合において、バイパス交流電源６の停電が発生したときには、インバータ３２は副分担電流Ｉｓｓを出力する。このときインバータ３２は既に起動されて待機状態にされているので、電流指令値Ｉｃ１が増大された場合にはインバータ３２の出力電流は迅速かつスムーズに増大する。 When the corresponding selection signal SE1 is at the "H" level, which is the selection level, if a power outage occurs in the bypass AC power supply 6, the inverter 32 outputs the secondary shared current Iss. At this time, the inverter 32 has already been started and is in a standby state, so when the current command value Ic1 is increased, the output current of the inverter 32 increases quickly and smoothly.
　対応する選択信号ＳＥ１が非選択レベルの「Ｌ」レベルにされている場合には、バイパス交流電源６が健全か否かに関係なく、０Ａを出力し、待機状態に維持される。 When the corresponding selection signal SE1 is at the non-selection level "L", the bypass AC power supply 6 outputs 0 A and is maintained in standby mode regardless of whether it is healthy or not.
　次に、この無停電電源システムの動作について説明する。バイパス交流電源６の健全時には、バイパスＥＣＯ給電モードが実行され、Ｎ台の無停電電源装置Ｕ１～ＵＮ（図１）に含まれるＮ個の半導体スイッチ２３（図４）がオンされ、各無停電電源装置Ｕにおいてバイパス交流電源６からリアクトル２１および半導体スイッチ２３を介して負荷８に交流電力が供給される。このとき、リアクトル２１により、Ｎ個の半導体スイッチ２３に流れる電流の大きさのばらつきが小さく抑制される。 Next, the operation of this uninterruptible power supply system will be described. When the bypass AC power supply 6 is healthy, the bypass ECO power supply mode is executed, N semiconductor switches 23 (FIG. 4) included in N uninterruptible power supplies U1 to UN (FIG. 1) are turned on, and AC power is supplied from the bypass AC power supply 6 to the load 8 via the reactor 21 and semiconductor switch 23 in each uninterruptible power supply U. At this time, the reactor 21 suppresses the variation in the magnitude of the current flowing through the N semiconductor switches 23 to a small value.
　また、各無停電電源装置Ｕの各パワーモジュールＰ（図６）において、コンバータ３１および双方向チョッパ３３によってバッテリＢが充電される。また、各パワーモジュールＰにおいてインバータ３２は、制御部３５（図６、図７）によって制御され、電流を出力せずにカウンタ電圧ＶＣを出力する待機状態にされる。 In addition, in each power module P (FIG. 6) of each uninterruptible power supply U, the battery B is charged by the converter 31 and bidirectional chopper 33. In each power module P, the inverter 32 is controlled by the control unit 35 (FIGS. 6 and 7) and is placed in a standby state in which it outputs the counter voltage VC without outputting any current.
　負荷電流ＩＬが電流検出器２（図１）によって検出され、その検出値に基づいて制御装置５（図２）によって各無停電電源装置Ｕの分担電流Ｉｓが求められ、その分担電流Ｉｓを示す信号φＩｓが各無停電電源装置Ｕの制御部２８（図４）に与えられる。 The load current IL is detected by the current detector 2 (Figure 1), and the control device 5 (Figure 2) calculates the shared current Is of each uninterruptible power supply U based on the detected value, and a signal φIs indicating the shared current Is is sent to the control unit 28 (Figure 4) of each uninterruptible power supply U.
　制御部２８により、信号φＩｓによって示される分担電流Ｉｓを効率よく供給するために必要な数ｍのパワーモジュールＰが選択されるとともに、選択されたパワーモジュールＰが負荷８に供給すべき副分担電流Ｉｓｓが求められる。 The control unit 28 selects the number m of power modules P required to efficiently supply the shared current Is indicated by the signal φIs, and determines the sub-shared current Iss that the selected power modules P should supply to the load 8.
　バイパス交流電源６の停電が発生すると、Ｎ個の半導体スイッチ２３がオフされ、バイパス交流電源６と負荷８の間が瞬時に遮断される。また、各無停電電源装置Ｕの選択されたｍ台のパワーモジュールＰの各々から負荷８に副分担電流Ｉｓｓが供給され、負荷８の運転が継続される。 When a power outage occurs in the bypass AC power supply 6, the N semiconductor switches 23 are turned off, and the bypass AC power supply 6 is instantly disconnected from the load 8. In addition, the sub-shared current Iss is supplied to the load 8 from each of the selected m power modules P of each uninterruptible power supply U, and the operation of the load 8 continues.
　バイパス交流電源６が健全状態に復旧すると、Ｎ台の無停電電源装置Ｕ１～ＵＮ（図１）に含まれるＮ個の半導体スイッチ２３（図４）がオンされ、各無停電電源装置Ｕにおいて、バイパス交流電源６からリアクトル２１および半導体スイッチ２３を介して負荷８に交流電力が供給されるとともに、各パワーモジュールＰが待機状態に戻される。 When the bypass AC power supply 6 is restored to a healthy state, the N semiconductor switches 23 (Fig. 4) included in the N uninterruptible power supplies U1 to UN (Fig. 1) are turned on, and in each uninterruptible power supply U, AC power is supplied from the bypass AC power supply 6 to the load 8 via the reactor 21 and semiconductor switch 23, and each power module P is returned to a standby state.
　図８は、本実施の形態の比較例となる無停電電源システムの要部を示す回路ブロック図であって、図４と対比される図である。図８を参照して、比較例が本実施の形態と異なる点は、リアクトル２１が除去され、半導体スイッチ２３の一方端子がバイパス端子Ｔ１に直接接続されている点である。 FIG. 8 is a circuit block diagram showing the main parts of an uninterruptible power supply system that is a comparative example of this embodiment, and is a diagram to be compared with FIG. 4. Referring to FIG. 8, the comparative example differs from this embodiment in that the reactor 21 is removed, and one terminal of the semiconductor switch 23 is directly connected to the bypass terminal T1.
　図９は、比較例となる無停電電源システムのバイパスＥＣＯ給電モードを説明するための回路ブロック図である。図９において、バイパスＥＣＯ給電モード時には、Ｎ個の半導体スイッチ２３がオンされ、バイパス交流電源６からＮ個の半導体スイッチ２３の並列接続体を介して負荷８に電流ＩＬが供給される。 FIG. 9 is a circuit block diagram for explaining the bypass ECO power supply mode of an uninterruptible power supply system serving as a comparative example. In FIG. 9, in the bypass ECO power supply mode, N semiconductor switches 23 are turned on, and a current IL is supplied from the bypass AC power supply 6 to the load 8 via the parallel connection of N semiconductor switches 23.
　Ｎ個の半導体スイッチ２３に流れる電流の値をそれぞれＩ１～ＩＮとすると、Ｉ１～ＩＮの和はＩＬとなる。Ｎ個の半導体スイッチ２３のしきい値電圧Ｖｔが互いに一致している場合には、負荷電流ＩＬがＮ個の半導体スイッチ２３に均等に分流され、各半導体スイッチ２３には負荷電流ＩＬのＮ分の１の電流ＩＬ／Ｎが流れる。 If the values of the currents flowing through the N semiconductor switches 23 are I1 to IN, respectively, the sum of I1 to IN is IL. When the threshold voltages Vt of the N semiconductor switches 23 are the same, the load current IL is evenly distributed to the N semiconductor switches 23, and a current IL/N that is 1/N of the load current IL flows through each semiconductor switch 23.
　しかし、実際には、Ｎ個の半導体スイッチ２３のしきい値電圧Ｖｔは定格値Ｖｔｃから１０～３０％程度の範囲内でばらつく。このため、バイパスＥＣＯ給電モード時にＮ個の半導体スイッチ２３に流れる電流の値Ｉ１～ＩＮは一定値ＩＬ／Ｎにならず、大きな範囲にばらつく。 However, in reality, the threshold voltages Vt of the N semiconductor switches 23 vary within a range of about 10 to 30% from the rated value Vtc. For this reason, the values of the currents I1 to IN flowing through the N semiconductor switches 23 in the bypass ECO power supply mode do not become a constant value IL/N, but vary over a large range.
　図１０は、比較例における半導体スイッチ２３のＶ－Ｉ特性を例示する図である。図１０において、曲線Ａは、定格しきい値電圧Ｖｔｃを有する半導体スイッチ２３のＶ－Ｉ特性を示している。曲線Ｂは、Ｎ個の半導体スイッチ２３のうちの最小のしきい値電圧Ｖｔ１を有する半導体スイッチ２３のＶ－Ｉ特性を示している。曲線Ｃは、Ｎ個の半導体スイッチ２３のうちの最大のしきい値電圧Ｖｔ２を有する半導体スイッチ２３のＶ－Ｉ特性を示している。 FIG. 10 is a diagram illustrating the VI characteristics of semiconductor switches 23 in a comparative example. In FIG. 10, curve A shows the VI characteristics of a semiconductor switch 23 having a rated threshold voltage Vtc. Curve B shows the VI characteristics of a semiconductor switch 23 having the smallest threshold voltage Vt1 among the N semiconductor switches 23. Curve C shows the VI characteristics of a semiconductor switch 23 having the largest threshold voltage Vt2 among the N semiconductor switches 23.
　半導体スイッチ２３の制御電圧Ｖを上昇させると、半導体スイッチ２３に流れる電流Ｉは増大する。Ｎ個の半導体スイッチ２３に同じ制御電圧Ｖａを印加すると、最小のしきい値電圧Ｖｔ１を有する半導体スイッチ２３には最大の電流Ｉａ１が流れ、最大のしきい値電圧Ｖｔ２を有する半導体スイッチ２３には最小の電流Ｉａ２が流れ、Ｎ個の半導体スイッチ２３に流れる電流はＩａ１からＩａ２まで大きくばらつく。このため、大電流Ｉａ１を安定に流すことが可能な大型で高価格の半導体スイッチ２３を使用する必要があり、システムの大型化、コスト高を招くという問題がある。 When the control voltage V of the semiconductor switch 23 is increased, the current I flowing through the semiconductor switch 23 increases. When the same control voltage Va is applied to N semiconductor switches 23, the maximum current Ia1 flows through the semiconductor switch 23 having the minimum threshold voltage Vt1, and the minimum current Ia2 flows through the semiconductor switch 23 having the maximum threshold voltage Vt2, so that the current flowing through the N semiconductor switches 23 varies greatly from Ia1 to Ia2. For this reason, it is necessary to use a large, expensive semiconductor switch 23 capable of stably passing the large current Ia1, which poses the problem of an increase in the size and cost of the system.
　図１１は、本実施の形態に従う無停電電源システムのバイパスＥＣＯ給電モードを説明するための回路ブロック図である。図１１において、バイパスＥＣＯ給電モード時には、Ｎ台の無停電電源装置Ｕ１～ＵＮに含まれるＮ個の半導体スイッチ２３がオンされ、バイパス交流電源６からＮ台の無停電電源装置Ｕ１～ＵＮの並列接続体を介して負荷８に交流電力が供給される。このとき、各無停電電源装置Ｕは、リアクトル２１および半導体スイッチ２３の直列接続体を含む。 FIG. 11 is a circuit block diagram for explaining the bypass ECO power supply mode of the uninterruptible power supply system according to this embodiment. In FIG. 11, in the bypass ECO power supply mode, N semiconductor switches 23 included in N uninterruptible power supplies U1 to UN are turned on, and AC power is supplied from the bypass AC power source 6 to the load 8 via the parallel connection of the N uninterruptible power supplies U1 to UN. At this time, each uninterruptible power supply U includes a series connection of a reactor 21 and a semiconductor switch 23.
　図１２は、リアクトル２１のＶ－Ｉ特性を例示する図である。図１２において、リアクトル２１に印加する電圧Ｖを上昇させると、リアクトル２１に流れる電流Ｉは電圧Ｖに比例して増大する。リアクトル２１は電線をコイル状に巻回したものであり、各リアクトル２１のインピーダンスは調整可能である。これに対して半導体スイッチ２３のしきい値電圧Ｖｔを半導体スイッチ２３の製造後に調整することはできない。このため、リアクトル２１の特性ばらつきは、半導体スイッチ２３のしきい値電圧Ｖｔのばらつきに比べて充分に小さい。 FIG. 12 is a diagram illustrating the V-I characteristics of reactor 21. In FIG. 12, when the voltage V applied to reactor 21 is increased, the current I flowing through reactor 21 increases in proportion to the voltage V. Reactor 21 is an electric wire wound into a coil, and the impedance of each reactor 21 is adjustable. In contrast, the threshold voltage Vt of semiconductor switch 23 cannot be adjusted after semiconductor switch 23 is manufactured. For this reason, the characteristic variation of reactor 21 is sufficiently small compared to the variation of threshold voltage Vt of semiconductor switch 23.
　図１３は、本実施の形態におけるリアクトル２１および半導体スイッチ２３の直列接続体のＶ－Ｉ特性を例示する図である。曲線Ｄ，Ｅ，Ｆはそれぞれ曲線Ａ，Ｂ，Ｃにリアクトル２１のＶ－Ｉ特性を加算したものとなる。 FIG. 13 is a diagram illustrating the VI characteristics of a series connection of reactor 21 and semiconductor switch 23 in this embodiment. Curves D, E, and F are obtained by adding the VI characteristics of reactor 21 to curves A, B, and C, respectively.
　半導体スイッチ２３に印加する制御電圧Ｖを上昇させると、リアクトル２１および半導体スイッチ２３の直列接続体に流れる電流Ｉは増大するが、この電流Ｉは、リアクトル２１のインピーダンスによって制限され、比較例の電流Ｉ（図１０）と比べて小さくなる。 When the control voltage V applied to the semiconductor switch 23 is increased, the current I flowing through the series connection of the reactor 21 and the semiconductor switch 23 increases, but this current I is limited by the impedance of the reactor 21 and becomes smaller than the current I in the comparative example (Figure 10).
　Ｎ個の半導体スイッチ２３に同じ制御電圧Ｖａを印加すると、最小のしきい値電圧Ｖｔ１を有する半導体スイッチ２３には最大の電流Ｉｂ１が流れ、最大のしきい値電圧Ｖｔ２を有する半導体スイッチ２３には最小の電流Ｉｂ２が流れ、Ｎ個の半導体スイッチ２３に流れる電流はＩｂ１からＩｂ２までばらつく。 When the same control voltage Va is applied to N semiconductor switches 23, the maximum current Ib1 flows through the semiconductor switch 23 with the minimum threshold voltage Vt1, and the minimum current Ib2 flows through the semiconductor switch 23 with the maximum threshold voltage Vt2, so that the current flowing through the N semiconductor switches 23 varies from Ib1 to Ib2.
　しかし、図１０および図１３から分かるように、Ｉｂ２とＩｂ１の差はＩａ２とＩａ１の差よりも小さくなる。このため、比較例に比べ、小型で低価格の半導体スイッチ２３を使用することが可能となり、システムの低コスト化を図ることができる。 However, as can be seen from Figures 10 and 13, the difference between Ib2 and Ib1 is smaller than the difference between Ia2 and Ia1. Therefore, compared to the comparative example, it is possible to use a smaller, lower-cost semiconductor switch 23, which allows for lower system costs.
　換言すると、比較例（図９）では、Ｎ個の半導体スイッチ２３のインピーダンスＺｓのばらつきが大きいので、Ｎ個の半導体スイッチ２３に流れる電流Ｉ１～ＩＮのばらつきが大きい。 In other words, in the comparative example (Figure 9), the impedance Zs of the N semiconductor switches 23 varies greatly, and therefore the currents I1 to IN flowing through the N semiconductor switches 23 vary greatly.
　これに対して本実施の形態（図１１）では、Ｎ個のリアクトル２１のインピーダンスＺｘのばらつきは十分に小さい。したがって、Ｎ個のリアクトル２１および半導体スイッチ２３の直列接続体のインピーダンスＺ＝Ｚｘ＋Ｚｓのばらつきは、Ｎ個の半導体スイッチ２３のインピーダンスＺｓのばらつきよりも小さくなる。よって、本実施の形態におけるＮ個の半導体スイッチ２３に流れる電流Ｉ１～ＩＮのばらつきは、比較例におけるＮ個の半導体スイッチ２３に流れる電流Ｉ１～ＩＮのばらつきよりも小さくなる。このため、比較例に比べ、小型で低価格の半導体スイッチ２３を使用することが可能となる。 In contrast, in this embodiment (FIG. 11), the variation in impedance Zx of the N reactors 21 is sufficiently small. Therefore, the variation in impedance Z=Zx+Zs of the series connection of N reactors 21 and semiconductor switches 23 is smaller than the variation in impedance Zs of the N semiconductor switches 23. Therefore, the variation in currents I1 to IN flowing through the N semiconductor switches 23 in this embodiment is smaller than the variation in currents I1 to IN flowing through the N semiconductor switches 23 in the comparative example. For this reason, it is possible to use semiconductor switches 23 that are smaller and less expensive than those in the comparative example.
　以上のように、この実施の形態では、各無停電電源装置Ｕがバイパス交流電源６と負荷８の間に直列接続されるリアクトル２１および半導体スイッチ２３を含むので、各半導体スイッチ２３をオンすると、負荷電流ＩＬはＮ個のリアクトル２１および半導体スイッチ２３の直列接続体に分流される。したがって、リアクトル２１がない場合に比べ、Ｎ個の半導体スイッチ２３に流れる電流Ｉ１～ＩＮの大きさのばらつきを小さく抑制することができ、半導体スイッチ２３の小型化、低コスト化を図ることができる。 As described above, in this embodiment, each uninterruptible power supply U includes a reactor 21 and a semiconductor switch 23 connected in series between the bypass AC power supply 6 and the load 8, so that when each semiconductor switch 23 is turned on, the load current IL is shunted to a series connection of N reactors 21 and semiconductor switches 23. Therefore, compared to a case where there is no reactor 21, the variation in the magnitude of the currents I1 to IN flowing through the N semiconductor switches 23 can be suppressed to a small value, and the semiconductor switches 23 can be made smaller and less expensive.
　今回開示された実施の形態はすべての点で例示であって制限的なものではないと考えられるべきである。本発明は上記した説明ではなくて請求の範囲によって示され、請求の範囲と均等の意味および範囲内でのすべての変更が含まれることが意図される。 The embodiments disclosed herein should be considered in all respects as illustrative and not restrictive. The present invention is defined by the claims rather than the above description, and is intended to include all modifications within the meaning and scope of the claims.
　１　無停電電源システム、Ｕ１～ＵＮ　無停電電源装置、Ｂ１～ＢＮ　バッテリ、２，ＣＤ１～ＣＤ３　電流検出器、３　通信線、４　操作部、５　制御装置、Ｔ１　バイパス端子、Ｔ２，Ｔ５　入力端子、Ｔ３，Ｔ６　直流端子、Ｔ４，Ｔ７　出力端子、６　バイパス交流電源、７　交流電源、８　負荷、１１，２７，３４　通信部、１２　演算部、１３，２８，３５　制御部、１４　報知部、２０　バイパススイッチ、２１，Ｌ１～Ｌ３　リアクトル、２２　バイパスモジュール、Ｐ１～ＰＭ　パワーモジュール、２３　半導体スイッチ、２４，２５　サイリスタ、２６　停電検出部、２９　記憶部、Ｆ１～Ｆ３　ヒューズ、Ｓ１～Ｓ３　スイッチ、Ｃ１～Ｃ３　コンデンサ、３１　コンバータ、ＤＬ　直流ライン、３２　インバータ、３３　双方向チョッパ、３６　故障検出部、　４１　電流指令部、４２　電圧制御部、４３　電流制御部、４４　ＰＷＭ制御部。 1 Uninterruptible power supply system, U1 to UN Uninterruptible power supply, B1 to BN Battery, 2, CD1 to CD3 Current detector, 3 Communication line, 4 Operation unit, 5 Control device, T1 Bypass terminal, T2, T5 Input terminal, T3, T6 DC terminal, T4, T7 Output terminal, 6 Bypass AC power supply, 7 AC power supply, 8 Load, 11, 27, 34 Communication unit, 12 Calculation unit, 13, 28, 35 Control unit, 14 Notification unit, 20 Bypass switch, 21, L1 ~L3 reactor, 22 bypass module, P1 to PM power module, 23 semiconductor switch, 24, 25 thyristor, 26 power failure detection unit, 29 memory unit, F1 to F3 fuses, S1 to S3 switches, C1 to C3 capacitors, 31 converter, DL DC line, 32 inverter, 33 bidirectional chopper, 36 fault detection unit, 41 current command unit, 42 voltage control unit, 43 current control unit, 44 PWM control unit.

Claims (5)

  1. 　負荷に対して並列接続される複数の無停電電源装置を備え、
    　各無停電電源装置は、
    　第１の交流電源の健全時にオンにされ、前記第１の交流電源の停電時にオフされる半導体スイッチと、
    　前記第１の交流電源と前記負荷の間に前記半導体スイッチと直列接続されるリアクトルと、
    　前記第１の交流電源の停電時に、直流電源から供給される直流電力を交流電力に変換して前記負荷に供給する電力変換器とを含む、無停電電源システム。     A plurality of uninterruptible power supplies are connected in parallel to a load,
    Each uninterruptible power supply is
    a semiconductor switch that is turned on when a first AC power source is normal and that is turned off when a power failure occurs in the first AC power source;
    a reactor connected in series with the semiconductor switch between the first AC power source and the load;
    and a power converter that, when a power failure occurs in the first AC power supply, converts DC power supplied from a DC power supply into AC power and supplies the AC power to the load.
  2. 　前記リアクトルは、複数の前記半導体スイッチに流れる電流の大きさのばらつきを小さく抑制するために設けられている、請求項１に記載の無停電電源システム。 The uninterruptible power supply system according to claim 1, wherein the reactor is provided to reduce variation in the magnitude of the current flowing through the multiple semiconductor switches.
  3. 　前記電力変換器は、前記第１の交流電源の健全時には、前記第１の交流電源から前記負荷に供給される交流電圧に応じた値のカウンタ電圧を前記負荷に出力することにより、前記第１の交流電源および前記負荷と電流を授受しない状態で待機する、請求項１に記載の無停電電源システム。 The uninterruptible power supply system according to claim 1, wherein the power converter, when the first AC power supply is healthy, outputs to the load a counter voltage having a value corresponding to the AC voltage supplied from the first AC power supply to the load, thereby waiting in a state in which no current is exchanged between the first AC power supply and the load.
  4. 　前記直流電源は電力貯蔵装置を含み、
    　前記電力変換器は、
    　第２の交流電源から供給される交流電力を直流電力に変換する順変換器と、
    　直流電力を交流電力に変換する逆変換器とを含み、
    　前記第１および第２の交流電源の健全時には、前記順変換器によって生成される直流電力が前記逆変換器に供給されるとともに前記電力貯蔵装置に蓄えられ、前記逆変換器は、前記第１の交流電源から前記負荷に供給される交流電圧に応じた値のカウンタ電圧を前記負荷に出力することにより、前記第１の交流電源および前記負荷と電流を授受しない状態で待機し、
    　前記第１および第２の交流電源の停電時には、前記電力貯蔵装置の直流電力が前記逆変換器に供給され、前記逆変換器は、前記電力貯蔵装置から供給される直流電力を交流電力に変換して前記負荷に供給する、請求項３に記載の無停電電源システム。     the DC power source includes a power storage device;
    The power converter includes:
    a converter that converts AC power supplied from the second AC power source into DC power;
    an inverter for converting DC power into AC power;
    when the first and second AC power sources are healthy, DC power generated by the forward converter is supplied to the inverter and stored in the power storage device, and the inverter outputs a counter voltage having a value corresponding to an AC voltage supplied from the first AC power source to the load to the load, thereby standing by without supplying or receiving a current to or from the first AC power source and the load;
    4. The uninterruptible power supply system according to claim 3, wherein, during a power outage of the first and second AC power sources, DC power from the power storage device is supplied to the inverter, and the inverter converts the DC power supplied from the power storage device into AC power and supplies it to the load.
  5. 　負荷電流を検出する電流検出器と、
    　前記電流検出器の検出結果に基づいて複数の前記電力変換器の各々が前記負荷に供給すべき分担電流を求める制御装置とをさらに備え、
    　各前記電力変換器は、前記第１の交流電源の停電時に、前記制御装置によって求められる分担電流を前記負荷に供給する、請求項１に記載の無停電電源システム。     a current detector for detecting a load current;
    a control device that calculates a current share to be supplied to the load by each of the plurality of power converters based on a detection result of the current detector,
    2. The uninterruptible power supply system according to claim 1, wherein each of the power converters supplies a current share determined by the control device to the load during a power outage of the first AC power supply.
PCT/JP2022/046179 2022-12-15 2022-12-15 Uninterruptible power supply system WO2024127578A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/JP2022/046179 WO2024127578A1 (en) 2022-12-15 2022-12-15 Uninterruptible power supply system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/JP2022/046179 WO2024127578A1 (en) 2022-12-15 2022-12-15 Uninterruptible power supply system

Publications (1)

Publication Number Publication Date
WO2024127578A1 true WO2024127578A1 (en) 2024-06-20

Family

ID=91484665

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2022/046179 WO2024127578A1 (en) 2022-12-15 2022-12-15 Uninterruptible power supply system

Country Status (1)

Country Link
WO (1) WO2024127578A1 (en)

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20130193761A1 (en) * 2012-01-31 2013-08-01 General Electric Company Systems, methods, and devices for control of parallel uninterruptible power supplies
WO2017009998A1 (en) * 2015-07-16 2017-01-19 東芝三菱電機産業システム株式会社 Uninterruptible power supply system

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20130193761A1 (en) * 2012-01-31 2013-08-01 General Electric Company Systems, methods, and devices for control of parallel uninterruptible power supplies
WO2017009998A1 (en) * 2015-07-16 2017-01-19 東芝三菱電機産業システム株式会社 Uninterruptible power supply system

Similar Documents

Publication Publication Date Title
US9954369B2 (en) Power supply method and apparatus
TWI568140B (en) Uninterruptible power supply device
US7053502B2 (en) Power supply with uninterruptible function
US8203235B2 (en) AC and DC uninterruptible online power supplies
US10298006B2 (en) Energy storage system and method of driving the same
EP3226379B1 (en) Uninterruptible power supply apparatus
CN110417081B (en) Power supply circuit and uninterrupted power supply UPS system
WO2022236545A1 (en) Battery system and control method
CN112542830A (en) Power supply system
US20180331568A1 (en) Uninterruptible power supply system
KR20210051491A (en) A sts(static transfer switch) and an ups(uninterruptible power supply) module with the sts
CN111404399A (en) Power supply system
WO2024127578A1 (en) Uninterruptible power supply system
CN112970168B (en) Uninterruptible power supply device
US6961250B2 (en) Non-isolated AC power supply device and method for controlling the same
Lee et al. High-efficiency large-capacity uninterruptible power supply using bidirectional-switch-based NPC multilevel converter
JP2009247185A (en) System-cooperative inverter and its self-sustaining operation method
JP2002199620A (en) Uninterruptible power supply device
KR101343953B1 (en) Double conversion uninterruptible power supply of eliminated battery discharger
KR101371703B1 (en) Dc uninterrupted power supply
CN114256956A (en) DC power supply system
JP6668274B2 (en) Uninterruptible power supply system
JP2535222B2 (en) DC uninterruptible power supply
KR102570625B1 (en) Ups power changeover control system and method of on-off grid solar bidirectional inverter
WO2023026357A1 (en) Uninterruptible power supply device