JP5792697B2 - Uninterruptible power system - Google Patents

Description

  The present invention relates to an uninterruptible power supply, and more particularly to an uninterruptible power supply including an uninterruptible power supply module and a bypass circuit connected in parallel between an AC power supply and a load.

  Conventionally, an uninterruptible power supply device includes an uninterruptible power supply module and a bypass circuit connected in parallel between an AC power supply and a load. The uninterruptible power supply module includes a converter that converts AC power supplied from an AC power source into DC power, and an inverter that converts DC power from the converter or the power storage device to AC power and applies the load to a load. The bypass circuit includes a bypass switch and a thyristor connected in parallel between the AC power supply and the load. In the inverter power supply mode, AC power is supplied from the inverter to the load. In the bypass power supply mode, AC power is supplied from the AC power source to the load via the bypass circuit (see, for example, Patent Document 1).

JP 2009-278755 A

  However, the conventional uninterruptible power supply has a problem that power supply to the load is stopped when the bypass circuit fails in the bypass power supply mode.

  Therefore, a main object of the present invention is to provide an uninterruptible power supply device with high reliability of power supply to a load.

  The uninterruptible power supply according to the present invention includes an uninterruptible power supply module connected in parallel between an AC power supply and a load, and a bypass circuit. The uninterruptible power supply module includes a converter that converts AC power from an AC power source into DC power, and an inverter that converts DC power from the converter or the power storage device to AC power and applies the AC power to a load. The bypass circuit includes a bypass switch connected between the AC power source and the load, and a plurality of bypass modules. Each bypass module has a thyristor connected between the AC power supply and the load, and an inverter power supply that turns on the bypass switch in the bypass power supply mode that supplies the AC power from the AC power supply to the load and supplies the AC power from the inverter to the load. A control unit that turns off the bypass switch in the mode and turns on the thyristor and the bypass switch when the uninterruptible power supply module fails in the inverter power supply mode.

Preferably, only the control unit of the master module is a one bypass module selected among the plurality of bypass modules to turn on or off the bypass switch.

  Preferably, when the master module fails, one bypass module selected from the remaining one or two or more bypass modules becomes the master module.

  Preferably, a plurality of uninterruptible power supply modules are provided, and the plurality of uninterruptible power supply modules are connected in parallel between an AC power supply and a load.

  In the uninterruptible power supply according to the present invention, the bypass circuit includes a bypass switch and a plurality of bypass modules. Therefore, since a plurality of bypass modules that are likely to fail are provided, it is possible to prevent the bypass circuit from failing and to improve the reliability of power supply to the load.

It is a circuit block diagram which shows the structure of the uninterruptible power supply by one embodiment of this invention. It is a circuit block diagram which shows the structure of the uninterruptible power supply module shown in FIG. It is a block diagram which shows the structure of the bypass module shown in FIG. FIG. 2 is a circuit block diagram illustrating a relationship between two bypass modules illustrated in FIG. 1. FIG. 5 is a block diagram illustrating a configuration of a portion related to generation of signals φB, φI, and φF illustrated in FIG. 4. It is a block diagram which shows the bypass switch shown in FIG. It is a time chart which shows the switching operation | movement of manual inverter electric power feeding and bypass electric power feeding in the uninterruptible power supply device shown in FIGS. It is a time chart which shows the switching operation | movement of the inverter electric power feeding and bypass electric power feeding by the failure in the uninterruptible power supply device shown in FIGS.

  As shown in FIG. 1, an uninterruptible power supply according to an embodiment of the present invention includes an input terminal TI, an output terminal TO, a battery terminal TB, a plurality (three in the figure) of uninterruptible power supply modules U1 to U3, a plurality It includes two bypass modules B1 and B2 and a bypass switch BS. The input terminal TI receives commercial frequency AC power from the AC power source 1. The output terminal TO is connected to the load 2. The battery terminal TB is connected to the battery 3.

  The plurality of uninterruptible power supply modules U1 to U3 are connected in parallel between the input terminal TI and the output terminal TO. The plurality of bypass modules B1 and B2 are connected in parallel between the input terminal TI and the output terminal TO. The bypass switch BS is connected between the input terminal TI and the output terminal TO. The plurality of bypass modules B1 and B2 and the bypass switch BS constitute a bypass circuit.

  FIG. 2 is a circuit block diagram showing a configuration of the uninterruptible power supply module U1. In FIG. 2, the uninterruptible power supply module U1 includes an input terminal T1, an output terminal T2, a battery terminal T3, switches S1 to S3, capacitors C1 to C4, reactors L1 to L3, a converter 5, an inverter 6, and a bidirectional chopper 7. Including.

  Terminals T1 to T3 are connected to terminals TI, TO, and TB, respectively. Switch S1 and reactor L1 are connected in series between input terminal T1 and input node 5a of converter 5. Capacitor C1 is connected between a node between switch S1 and reactor L1 and a reference voltage line. Switch S1 is normally turned on, and is turned off, for example, during maintenance of uninterruptible power supply module U1. Capacitor C1 and reactor L1 allow the AC power from AC power supply 1 to pass through converter 5 and prevent the carrier frequency signal generated by converter 5 from leaking to AC power supply 1 side (low-pass filter). Configure.

  Converter 5 converts AC power from AC power supply 1 into DC power. Capacitor C4 is connected between output node 5b of converter 5 and the reference voltage line, and smoothes the output voltage of converter 5. Output node 5b of converter 5, input node 6a of inverter 6, and first input / output node 7a of bidirectional chopper 7 are connected to each other. The inverter 6 converts the DC power from the converter 5 or the bidirectional chopper 7 into AC power having a commercial frequency.

  Reactor L2 and switch S2 are connected in series between output node 6b of inverter 6 and output terminal T2. Capacitor C2 is connected between a node between reactor L2 and switch S2 and a reference voltage line. Reactor L2 and capacitor C2 constitute an AC output filter (low-pass filter) that allows AC power from inverter 6 to pass through load 2 and prevents a carrier frequency signal generated by inverter 6 from leaking to load 2 side. To do.

  The switch S2 is turned on in the inverter power supply mode in which the AC power generated by the inverter 6 is supplied to the load 2, and in the bypass power supply mode in which the AC power from the AC power source 1 is supplied to the load 2 via the bypass switch BS. Turned off. Further, the switch S2 is turned off at the time of maintenance or failure of the uninterruptible power supply module U1.

  Switch S3 and reactor L3 are connected in series between battery terminal T3 and second input / output node 7b of bidirectional chopper 7. Capacitor C3 is connected between a node between switch S3 and reactor L3 and a reference voltage line. The switch S3 is normally turned on, and is turned off, for example, when the uninterruptible power supply module U1 or the battery 3 is maintained. Capacitor C3 and reactor L3 constitute a low-pass filter that passes DC power and prevents a carrier frequency signal generated by bidirectional chopper 7 from leaking to battery 3 side.

  The bi-directional chopper 7 supplies the DC power generated by the converter 5 to the battery 3 during normal times when the AC power is supplied from the AC power source 1, and the power failure in which the supply of AC power from the AC power source 3 is stopped. At that time, the DC power of the battery 3 is supplied to the inverter 6.

  Here, the operation of the uninterruptible power supply module U1 will be briefly described. During normal times when AC power is supplied from the AC power source 1, the AC power is converted into DC power by the converter 5. The DC power is converted into AC power by the inverter 6 and supplied to the load 2, and is stored in the battery 3 by the bidirectional chopper 7.

  When a power failure occurs and the supply of AC power from the AC power supply 1 is stopped, the operation of the converter 5 is stopped, the DC power of the battery 3 is supplied to the inverter 6 by the bidirectional chopper 7, and the AC power is supplied by the inverter 6. To be supplied to the load 2. Therefore, even when a power failure occurs, the operation of the load 2 can be continued during the period in which the DC power is stored in the battery 3. The uninterruptible power supply modules U2 and U3 have the same configuration as the uninterruptible power supply module U1.

  In this uninterruptible power supply, even when any one of the three uninterruptible power supply modules U1 to U3 fails, the remaining two uninterruptible power supply modules U operate the load 2. The redundancy method that can continue is adopted.

  FIG. 3 is a block diagram showing a configuration of the bypass module B1. In FIG. 3, the bypass module B <b> 1 includes an input terminal Ta, an output terminal Tb, a thyristor 10, and a control unit 11. Terminals Ta and Tb are connected to terminals TI and TO, respectively. The thyristor 10 is connected between the terminals Ta and Tb and controlled by the control unit 11 to be turned on or off. The thyristor 10 is turned on when two or more uninterruptible power supply modules U fail in the inverter power supply mode.

  The control unit 11 controls the thyristor 10 based on the bypass power supply command signal φB, the inverter power supply command signal φI, the failure detection signal φF, and the answerback signal BSAX, as well as the bypass switch control signal φBS1, the on command signal φS2ON1, and An off command signal φS2OFF1 is output.

  The bypass module B2 has the same configuration as the bypass module B1. The control unit 9 of the bypass module B2 controls the thyristor 10 based on the bypass power supply command signal φB, the inverter power supply command signal φI, the failure detection signal φF, and the answerback signal BSAX, and also controls the bypass control signal φBS2 and the on command signal. φS2ON2 and off command signal φS2OFF2 are output.

  FIG. 4 is a circuit block diagram showing the relationship between the output signals φBS1, φS2ON1, φS2OFF1 of the bypass module B1 and the output signals φBS2, φS2ON2, φS2OFF2 of the bypass module B2. 4, the uninterruptible power supply includes OR gates 12 to 14. OR gate 12 outputs a logical sum signal of signals φBS1 and φBS2 as signal φBS. OR gate 13 outputs a logical sum signal of signals φS2ON1 and φS2ON2 as signal φS2ON. The OR gate 14 outputs a logical sum signal of the signals φS2OFF1 and φS2OFF2 as a signal φS2OFF.

  FIG. 5 is a block diagram showing a portion related to generation of signals φB, φI, and φF shown in FIG. The uninterruptible power supply device includes an operation unit 15, a control unit 16, and a failure detection unit 17. The operation unit 15 is provided with a button for switching between the bypass power supply mode and the inverter power supply mode. The user of the uninterruptible power supply can manually switch between the bypass power supply mode and the inverter power supply mode by operating the operation unit 15. The failure detection unit 17 detects the presence or absence of each failure of the uninterruptible power supply modules U1 to U3, and outputs a signal indicating the detection result.

  The control unit 16 outputs a bypass power supply command signal φB when the operation unit 15 sets the bypass power supply mode, and outputs an inverter power supply command signal φI when the inverter power supply mode is set. Further, based on the detection result of the failure detection unit 17, the control unit 16 changes the failure detection signal φF from “L” level to “H” when two or more uninterruptible power supply modules U fail in the inverter power supply mode. Launch to level.

  FIG. 6 is a block diagram showing the bypass switch BS. In FIG. 6, the bypass switch BS is connected between the input terminal TI and the output terminal TO, and is turned on when the bypass control signal φBS is set to the “H” level, and when the signal φBS is set to the “L” level. Turn off. The bypass switch BS sets the answer back signal BSAX to “H” level when actually turned on in response to the signal φBS, and sets the answer back signal BSAX to “L” when actually turned off in response to the signal φBS. To level. The answerback signal BSAX is given to the control unit 11 of the bypass modules B1 and B2.

  The control unit (not shown) of the uninterruptible power supply module U turns on the switch S2 in response to the on command signal φS2ON from the control unit 9, and turns on the switch S2 in response to the off command signal φS2OFF from the control unit 9. Turn off.

  FIGS. 7A to 7I are time charts showing a switching operation between manual inverter power feeding and bypass power feeding. In the initial state, the uninterruptible power supply device is set to the bypass power supply mode. Inverter 6 is operating normally, and failure detection signal φF is at “L” level. Bypass control signal φBS is set to “H” level, answerback signal BSAX is set to “H” level, and bypass switch BS is actually turned on. Further, the thyristor 10 is off.

  When switching from the bypass power supply mode to the inverter power supply mode is instructed at the operation unit 15 at a certain time, the inverter power supply command signal φI is set to the “H” level for a predetermined time. In response to the falling edge of the inverter power supply command signal φI, the ON command signal φS2ON is set to the “H” level for a predetermined time, and the switch S2 of each uninterruptible power supply module U is turned on.

  Further, the bypass control signal φBS falls from the “H” level to the “L” level in synchronization with the falling edge of the ON command signal φS2ON. When the bypass control signal φBS is lowered to the “L” level, the bypass switch BS is turned off after a predetermined response time, and the answer back signal BSAX is lowered from the “H” level to the “L” level (time t0). Thereby, switching from bypass power supply to inverter power supply is completed.

  Next, when switching from the inverter power supply mode to the bypass power supply mode is instructed at the operation unit 15 at a certain time t1, the bypass power supply command signal φB is set to the “H” level for a predetermined time. In response to the falling edge of bypass power supply command signal φB, bypass control signal φBS is raised from the “L” level to the “H” level. When bypass control signal φBS is raised to “H” level, bypass switch BS is turned on after a predetermined response time, and answerback signal BSAX is raised from “L” level to “H” level. In response to the rising edge of the answer back signal BSAX, the off command signal φS2OFF is raised to “H” level for a predetermined time, and the switch S2 of each uninterruptible power supply module U is turned off. Thereby, the switching from the inverter power supply to the bypass power supply ends.

  FIGS. 8A to 8I are time charts showing a switching operation from inverter power supply to bypass power supply due to a failure. If inverters 6 of two or more uninterruptible power supply modules U fail and stop during power feeding at a certain time t1, failure detection signal φF is raised from “L” level to “H” level. In response to the rising edge of the failure detection signal φF, the thyristors 10 of the two bypass modules B1 and B2 are turned on, and AC power is supplied from the AC power supply 1 to the load 2 via the two thyristors 10. As a result, switching from inverter power supply to bypass power supply is performed without instantaneous interruption.

  In response to the rising edge of failure detection signal φF, bypass control signal φBS is raised from the “L” level to the “H” level. When bypass control signal φBS is raised to “H” level, bypass switch BS is turned on after a predetermined response time, and answerback signal BSAX is raised from “L” level to “H” level. In response to the rising edge of the answer back signal BSAX, the off command signal φS2OFF is raised to “H” level for a predetermined time, and the switch S2 of each uninterruptible power supply module U is turned off. Thereby, the switching from the inverter power supply to the bypass power supply due to the failure ends.

  In this embodiment, the bypass circuit includes a bypass switch BS and a plurality of bypass modules B1 and B2. Therefore, since a plurality of bypass modules B that are prone to failure are provided, bypass power feeding can be performed even when one bypass module B fails, and the reliability of power feeding to the load 2 can be improved.

  In this embodiment, the two bypass modules B1 and B2 are operated in the same manner, but one bypass module (for example, B1) is used as a master module and the other bypass module (in this case, B2) is used as a slave module. Also good. In this case, the master module B1 outputs signals φBS1, φS2ON1, and φS2OFF1, and the slave module B2 does not output signals φBS2, φS2ON2, and φS2OFF2. Therefore, the bypass switch BS and the switch S2 are controlled only by the master module B1. However, even in this case, when two or more uninterruptible power supply modules U fail, the thyristors 10 of the two bypass modules B1 and B2 are turned on.

  When the master module B1 fails, the bypass module B2 becomes the master module. In this case, the slave module B2 outputs signals φBS2, φS2ON2, and φS2OFF2. Therefore, the bypass switch BS and the switch S2 are controlled only by the master module B2.

  Also, which of the bypass modules B1 and B2 is to be the master module may be determined between the bypass modules B1 and B2 connected to each other via a communication line. Alternatively, the master / slave may be selected in the operation unit 15 and the control unit 16 in FIG.

  In this embodiment, two bypass modules B1 and B2 are provided, but three or more (for example, five) bypass modules B may be provided. In this case, one bypass module among the five bypass modules B is selected as the master module B, and each of the remaining four bypass modules is used as a slave module. When the master module B fails, one of the remaining four bypass modules B is selected as a master module, and each of the remaining three bypass modules B is used as a slave module. Similarly, the bypass circuit operates until the last one bypass module B fails.

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

  1 AC power source, 2 load, 3 battery, 5 converter, 6 inverter, 7 bidirectional chopper, 10 thyristor, 11, 16 control unit, 12-14 OR gate, 15 operation unit, 16 failure detection unit, TI, T1, Ta Input terminal, TO, T2, Tb output terminal, TB, T3 battery terminal, U1-U3 uninterruptible power supply module, B1, B2 bypass module, BS bypass switch, S1-S3 switch, L1-L3 reactor, C1-C4 capacitor.

Claims (4)

Equipped with an uninterruptible power supply module and bypass circuit connected in parallel between the AC power supply and the load,
The uninterruptible power supply module is
A converter that converts AC power from the AC power source into DC power;
An inverter that converts DC power from the converter or the power storage device into AC power and applies the AC power to the load,
The bypass circuit is:
A bypass switch connected between the AC power source and the load;
Including a plurality of bypass modules,
Each bypass module
A thyristor connected between the AC power source and the load;
The bypass switch is turned on in a bypass power supply mode for supplying AC power from the AC power source to the load, and the bypass switch is turned off in an inverter power supply mode for supplying AC power from the inverter to the load. An uninterruptible power supply comprising: a controller that turns on the thyristor and the bypass switch when the uninterruptible power supply module fails in mode. Wherein only the control unit of the master module is selected one bypass modules were of the plurality of bypass modules to turn on or off the bypass switch, the uninterruptible power supply of claim 1.   The uninterruptible power supply according to claim 2, wherein, when the master module fails, a selected one bypass module among the remaining one or two or more bypass modules becomes the master module. A plurality of the uninterruptible power supply modules are provided,
The uninterruptible power supply according to any one of claims 1 to 3, wherein the plurality of uninterruptible power supply modules are connected in parallel between the AC power supply and the load.

Images