JP2012060845A - Uninterruptible power-supply system and method of controlling operation of standby uninterruptible power-supply unit used therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an uninterruptible power-supply system that causes little power loss and a method of controlling operation of a standby uninterruptible power-supply unit used therefor.SOLUTION: According to an embodiment, the standby uninterruptible power-supply unit, which is connected to a permanent uninterruptible power-supply unit, includes an IGBT converter and a diode rectifier connected in parallel to a commercial power, and a measuring instrument which measures a value of a current supplied to a load. When the current value has exceeded a threshold value set in advance, the measuring instrument transmits a start signal to cause the IGBT converter to start an operation and controls the standby uninterruptible power-supply unit such that power is not supplied to the diode rectifier. When the standby uninterruptible power-supply unit is in a standby state, the measuring instrument transmits a stop signal to cause the IGBT converter to stop the operation and controls the standby uninterruptible power-supply unit such that power is supplied to the diode rectifier.

Description

  Embodiments described herein relate generally to an uninterruptible power supply system and an operation control method for a standby uninterruptible power supply used for the uninterruptible power supply system.

  Conventionally, power sources for critical load facilities such as Internet data centers, banks, and securities company online systems have to be maintained at constant voltage and constant frequency. (Hereinafter referred to as “UPS”) is generally used.

  In this UPS, a commercial AC power is converted into DC power by a built-in IGBT converter and a storage battery for backup use is charged as needed, and then the DC power is reversely converted to AC power by an IGBT inverter to load equipment. Power is being supplied.

  FIG. 3 is a configuration diagram of a conventional uninterruptible power supply system (hereinafter referred to as “UPS system”) that can supply power with higher reliability by combining two UPSs.

  The UPS system 100 of FIG. 3 has a regular UPS 110 and a spare UPS 120 connected to a commercial power supply 2 and is configured to supply power to the load facility 3 from any UPS.

  In this UPS system 100, power is supplied from the normal UPS 110 to the load equipment 3 in the normal state, and when the normal UPS 110 fails and stops, the switch 115 is switched by the uninterruptible switching device 114 built in the normal UPS 110, and the standby UPS 120 Electric power is supplied to the load facility 3.

JP 2006-60953 A

  In the conventional UPS system 100 described above, the IGBT converters 111 and 121 and the IGBT inverters 113 and 123 incorporated in the normal UPS 110 and the backup UPS 120 are both controlled by sine wave PWM, and high-frequency outflow of input current and output voltage. The forward conversion and the reverse conversion are performed while suppressing the occurrence of switching loss.

  Further, in the regular UPS 110 and the spare UPS 120, it is necessary to continuously perform the floating charging to the built-in storage batteries 112 and 122. Therefore, the IGBT converters 111 and 121 must be constantly operated.

  These “occurrence of switching loss in the IGBT converters 111 and 121” and “normal operation of the IGBT converters 111 and 121” have been obstacles in reducing the power loss of the UPS system 100.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an uninterruptible power supply system with low power loss and an operation control method for a standby uninterruptible power supply device used therefor.

  According to the embodiment for achieving the above object, a standby uninterruptible power supply connected to a normal uninterruptible power supply has an IGBT converter and a diode rectifier connected in parallel to a commercial power supply, and is connected to a load. It has a measuring instrument for measuring the current value supplied. When the current value exceeds a preset threshold, the measuring device transmits a start signal for starting the operation to the IGBT converter and controls the diode rectifier not to be supplied with power. When the current value is in a standby state, A stop signal for stopping the operation of the converter is transmitted and power is supplied to the diode rectifier.

It is a circuit diagram which shows the structure of the uninterruptible power supply system by one Embodiment. It is a block diagram which shows the structure of the measuring device of the uninterruptible power supply system by one Embodiment. It is a circuit diagram which shows the structure of the conventional uninterruptible power supply system.

<Configuration of Uninterruptible Power Supply System (UPS System) 1 According to One Embodiment>
A configuration of an uninterruptible power supply system (UPS system) 1 according to an embodiment of the present invention will be described with reference to FIG.

  The UPS system 1 according to the present embodiment includes a service UPS 10 connected to a commercial power source 2 and a spare UPS 20.

  The common UPS 10 includes an IGBT converter 11 that is a switching-compatible converter connected to the commercial power source 2, a storage battery 12 connected to the IGBT converter 11, an IGBT inverter 13 connected to the IGBT converter 11 and the storage battery 12, and an IGBT inverter 13. And an uninterruptible switch 14 connected to the backup UPS 20, and a bypass switch 15 for switching on / off of the connection between the uninterruptible switch 14 and the backup UPS 20.

  The spare UPS 20 is connected via a contactor 27 by an IGBT converter 21 connected to the commercial power source 2 by the main circuit 25 and a backup circuit 26 connected to the commercial power source 2 in parallel with the main circuit 25. Diode rectifier 28, converter switch 29 for switching connection to main circuit 25 or backup circuit 26, storage battery 22 connected to main circuit 25 or backup circuit 26 via converter switch 29, and converter switching The IGBT inverter 23 connected to the storage device 29 and the storage battery 22, the measuring instrument 30 connected to the IGBT inverter 23, the IGBT inverter 23 and the commercial power source 2, and the uninterruptible switching device 14 of the service UPS 10 are connected. Equipped with an uninterruptible switch 24 That.

  The IGBT converter 11 forward-converts AC power supplied from the commercial power source 2 into DC power.

  The storage battery 12 is float-charged as necessary by the DC power obtained by the forward conversion in the IGBT converter 11, and when the commercial power supply 2 fails and power supply becomes impossible, the storage battery 12 passes through the IGBT inverter 13. Then, power is supplied to the load facility 3.

  The IGBT inverter 13 reversely converts DC power obtained by forward conversion in the IGBT converter 11 into AC power.

  The uninterruptible switching device 14 connects the load equipment 3 to the IGBT inverter 13 when the IGBT converter 11, the storage battery 12, and the IGBT inverter 13 are operating normally, and the IGBT converter 11, the storage battery 12, or the IGBT inverter 13 When it is detected that an abnormality has occurred in any one of them, the load equipment 3 is switched to be connected to the backup UPS 20.

  The bypass switch 15 normally connects the uninterruptible switch 14 to the backup UPS 20 and switches to connect to the commercial power source 2 during maintenance of the backup UPS 20.

  The IGBT converter 21 is operated or stopped under the control of the measuring instrument 30, and at the time of operation, the AC power supplied from the commercial power source 2 is forward-converted to DC power.

  The storage battery 22 is float-charged as necessary by DC power obtained by forward conversion in the IGBT converter 21 or the diode rectifier 28, and when the commercial power source 2 fails and power supply becomes impossible, the IGBT 22 Electric power is supplied to the load facility 3 through the inverter 23.

  The IGBT inverter 23 reversely converts DC power obtained by forward conversion in the IGBT converter 21 or the diode rectifier 28 into AC power.

  The uninterruptible switching device 24 is connected to the IGBT inverter 23 when the IGBT converter 21, the storage battery 22, and the IGBT inverter 23 are operating normally, and any of the IGBT converter 21, the storage battery 22, or the IGBT inverter 23 is abnormal. When this occurs, switching is made so that the commercial power source 2 is directly connected.

  The diode rectifier 28 forward-converts AC power into DC power when the contactor 27 connected to the preceding stage is turned on and AC power is supplied from the commercial power supply 2.

  As shown in FIG. 2, the measuring instrument 30 includes a current measurement unit 31, a determination unit 32, and a device control unit 33.

  The current measuring unit 31 measures the current value of the power supplied from the IGBT inverter 23.

  The determination unit 32 determines whether or not the current value measured by the current measurement unit 31 exceeds a preset threshold value. This threshold value is set not to exceed a very small amount of current but to a value exceeding a current at which normal operation is performed in the load facility 3.

  When the determination unit 32 determines that the threshold value is exceeded, the device control unit 33 transmits a start signal that causes the IGBT converter 21 to start its operation so that power is supplied via the IGBT converter 21, and the contactor 27. Is turned off, and the converter switch 29 is controlled to be connected to the main circuit 25 so that power is not supplied to the diode rectifier 28.

  In addition, when the determination unit 32 determines that the threshold value is not exceeded, the device control unit 33 transmits a stop signal for stopping the operation to the IGBT converter 21 so that power is supplied via the diode rectifier 28, and The contactor 27 is controlled to be in an ON state, and the converter switch 29 is controlled to be connected to the backup circuit 26 side.

<Operation of Uninterruptible Power Supply System (UPS System) 1 According to One Embodiment>
In the UPS system 1 configured in this way, (1) when the service UPS 10 is operating normally, (2) when an error occurs in the service UPS 10 will be described.

(1) When the normal UPS 10 is operating normally First, in the IGBT converter 11 of the normal UPS 10, the AC power supplied from the commercial power source 2 is forward-converted to DC power.

  The DC power obtained by the forward conversion in the IGBT converter 11 is float-charged in the storage battery 12 as necessary, and is reversely converted from DC power to AC power in the IGBT inverter 13.

  When the IGBT converter 11, the storage battery 12, and the IGBT inverter 13 of the service UPS 10 are operating normally, the load facility 3 is switched to the IGBT inverter 13 by the uninterruptible switching device 14. The AC power supplied from the IGBT inverter 13 is supplied to the load facility 3 via the uninterruptible switching device 14.

  At this time, since no current is flowing from the backup UPS 20 to the load facility 3, only the current for charging the storage battery 22 is necessary in the backup UPS 20, and the current measuring unit 31 of the measuring instrument 30 The measured current value does not exceed the threshold value in the determination unit 32, and a stop signal for stopping the operation of the IGBT converter 21 is transmitted from the device control unit 33 so that the current flows through the diode rectifier 28, and the contactor 27 Is controlled to be ON, and the converter switch 29 is controlled to be connected to the backup circuit 26 side.

  By controlling as described above, when the normal UPS 10 operates normally and the backup UPS 20 is in a standby state and only the storage battery 22 is charged or only a small amount of current is required, the IGBT converter 21 is stopped and the control is performed. By performing forward conversion by the diode rectifier 28 that is not required, switching loss in the IGBT converter 21 and power loss due to normal operation can be reduced.

(2) When an abnormality occurs in the service UPS 10 When an error occurs in any of the IGBT converter 11, the storage battery 12, or the IGBT inverter 13 of the service UPS 10, this abnormality is detected by the uninterruptible switching device 14 and the load equipment 3 Are switched to be connected to the spare UPS 20.

  When the load facility 3 is switched so as to be connected to the backup UPS 20, power is supplied from the backup UPS 20 to the load facility 3, and the current value measured by the current measuring unit 31 of the measuring instrument 30 increases. .

  At this time, the IGBT converter 21 is in a stopped state, the contactor 27 is in an ON state, and the converter switch 29 is connected to the backup circuit 26 side.

  Then, when the increase in the current value is measured by the current measurement unit 31 of the measuring instrument 30 due to the supply of power from the backup UPS 20 to the load facility 3, the determination unit 32 determines that the threshold value has been exceeded.

  When the determination unit 32 determines that the current value exceeds the threshold value, the device control unit 33 transmits a start signal for starting the operation to the IGBT converter 21 so that power is supplied via the IGBT converter 21. The contactor 27 is controlled to be in the OFF state, and the converter switch 29 is controlled to be connected to the main circuit 25 side.

  By controlling in this way, when an abnormality occurs in the service UPS 10 and the backup UPS 20 is in an operating state and the current value of the supplied power is increased, the forward conversion is performed by the high-performance IGBT converter 21 instead of the diode rectifier 28. Is performed, it is possible to supply power with suppressed generation of harmonics.

  According to the above-described embodiment, when the backup UPS connected to the service UPS is in a standby state and when only a small amount of power is supplied, the power loss in the backup UPS is reduced by performing forward conversion with the diode rectifier. When the UPS is operating so that an abnormality occurs in the normal UPS and the spare UPS supplies more than a predetermined value, it is possible to supply power with suppressed harmonics by performing forward conversion with the IGBT converter. This enables efficient power supply.

  In the embodiment described above, the case where one normal UPS is connected to one spare UPS has been described. However, the present invention is not limited to this, and a plurality of normal UPSs are connected to one spare UPS. It may be. At that time, when an abnormality occurs in any one of the normal UPSs and the spare UPS is operating, a bypass switch that switches on / off of the connection between the non-instantaneous switching unit in the other regular UPS and the spare UPS. Is turned off and controlled not to be connected to the backup UPS. When the bypass switch is in the off state, the uninterruptible switch in the normal UPS is directly connected to the commercial power source. When an abnormality occurs in the IGBT converter, storage battery, or IGBT inverter in the normal UPS, the direct commercial power source is connected. AC power is supplied from

  Although the embodiment of the present invention has been described, this embodiment is presented as an example and is not intended to limit the scope of the invention. The novel embodiment can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. This embodiment and its modifications are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

1 ... UPS system 2 ... Commercial power supply 3 ... Load equipment 10 ... Usage UPS
DESCRIPTION OF SYMBOLS 11 ... IGBT converter 12 ... Storage battery 13 ... IGBT inverter 14 ... Uninterruptible switching device 15 ... Bypass switching device 20 ... Spare UPS
DESCRIPTION OF SYMBOLS 21 ... IGBT converter 22 ... Storage battery 23 ... IGBT inverter 24 ... Uninterruptible switching device 25 ... Main circuit 26 ... Backup circuit 27 ... Contactor 28 ... Diode rectifier 29 ... Converter switching device 30 ... Measuring device 31 ... Current measuring part 32 ... Determination Unit 33 ... Device control unit

Claims (3)

In an uninterruptible power supply system configured by connecting at least one regular uninterruptible power supply connected to a commercial power supply and a load facility and a standby uninterruptible power supply connected to a commercial power supply,
The common uninterruptible power supply is
An uninterruptible switching device that switches the load equipment to connect to the standby uninterruptible power supply when an abnormality occurs in its own device;
The standby uninterruptible power supply is
A switching-compatible converter and a diode rectifier that are connected in parallel to the commercial power source and forward-convert AC power supplied from the commercial power source,
A current measuring unit for measuring a current value of the supplied power;
A current value measured by the current measuring unit is set in advance when an abnormality occurs in the always-on uninterruptible power supply and the load facility is connected to the own device by the uninterruptible switching device. When the threshold value is exceeded, control is performed so that power is not supplied to the diode rectifier while transmitting a start signal to start the switching-compatible converter.
When the current value measured by the current measuring unit does not exceed a preset threshold value, a stop signal for stopping the operation of the switching-compatible converter is transmitted and power is supplied to the diode rectifier. An uninterruptible power supply system comprising an equipment control unit. The standby uninterruptible power supply is
A contactor installed in a preceding stage of the diode rectifier and switching between an ON state in which power is supplied from a commercial power source to the diode rectifier and an OFF state in which power is not supplied from the commercial power source to the diode rectifier;
An inverter that reverse-converts DC power forward-converted by the switching-compatible converter or the diode rectifier;
A converter switching unit that switches between a state in which the switching-compatible converter is connected to the inverter and a state in which the diode rectifier is connected to the inverter;
The device controller is
When controlling so that power is not supplied to the diode rectifier, the contactor is turned off and the converter switch is switched to a state in which the switching-compatible converter is connected to the inverter.
2. The control device according to claim 1, wherein when the power is supplied to the diode rectifier, the contactor is turned on, and the converter switch is switched to a state in which the diode rectifier is connected to the inverter. The uninterruptible power supply system described. A switching-compatible converter that is connected to at least one utility uninterruptible power supply connected to a commercial power source and a load facility, and is connected in parallel to the commercial power source and forward-converts AC power supplied from the commercial power source. And a standby uninterruptible power supply having a diode rectifier,
When a current value of power supplied from a commercial power source exceeds a preset threshold value due to an abnormality occurring in the uninterruptible uninterruptible power supply and switching so that the load facility is connected to the own apparatus. , A start signal for starting the operation to the switching compatible converter and controlling the power not to be supplied to the diode rectifier,
When the current value of the electric power supplied from the commercial power supply does not exceed a preset threshold value, a stop signal for stopping the operation is sent to the switching-compatible converter and electric power is supplied to the diode rectifier. And controlling the operation of the standby uninterruptible power supply.

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