JPH05146099A - Uninterruptible power supply - Google Patents

Abstract

PURPOSE:To make it possible to feed a load with power continuously even upon partial failure of uninterruptible power supply by switching first and second uninterruptible power supplies(UPS) between first and second operating modes as required. CONSTITUTION:A mode setter 17 has first and second set modes wherein switches 13,.4 are closed while a switch 15 is opened under first mode thus feeding AC outputs 3A, 3B from UPSs 11, 12 just like a normal UPS. When the mode setter 17 sets the second mode, the switches 13, 14 open while the switch 15 closes thus connecting the UPSs 11, 12 in cascade and producing only the AC output 3A. Such AC output 3A can be fed as a highly reliable AC power supply just like a parallel redundant UPS. Consequently, the load can be fed with power continuously even upon partial failure of the UPSs 11, 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply device, and more particularly to an uninterruptible power supply device having redundancy capable of continuously supplying power to a load even if a part of the device fails.

[0002]

2. Description of the Related Art As a conventional uninterruptible power supply, there is a bypass type uninterruptible power supply shown in FIG.

This device comprises a power converter 4 which outputs an AC power of constant voltage and constant frequency to an output side 3 by using an AC power source 2 or a battery 5 as an input power source, and a bypass circuit 6 which guides the AC power source 2 to the output side 3. I have it. The control unit 7 controls the power conversion unit 4 and, when detecting a failure of the device, stops the operation of the power conversion unit 4 and makes the bypass circuit 6 conductive.

In this conventional apparatus, when a failure occurs in the apparatus and the bypass circuit is turned on, the voltage of the AC power supply 2 is supplied to the output side 3 as it is. As a conventional uninterruptible power supply, there is a parallel redundant uninterruptible power supply shown in FIG.

In addition to the above-mentioned device, this device includes a plurality of batteries 5a and 5b, an AC power supply 2 or a battery 5.
A plurality of power conversion units 4a and 4b that output constant-voltage and constant-frequency AC power to the output side 3 using a and 5b as input power sources are provided.

The plurality of power conversion units 4a and 4b are always operated in parallel, and when a failure occurs in any of the power conversion units,
The control unit 7 stops the control of the failed power conversion unit and disconnects it, and the operation is continued only by the sound power conversion unit. Bypass circuit 6 when all power converters 4a and 4b fail
And the voltage of the AC power supply 2 is supplied to the output side 3 as it is.

[0007]

The above-mentioned parallel redundant type uninterruptible power supply requires the control of the cross current flowing between the plurality of power conversion units 4a and 4b and the control of the load balance, and the control circuit is complicated and expensive. However, it is difficult to provide it as a general-purpose power supply.

The present invention has been made in view of the above problems, and provides a general-purpose uninterruptible power supply capable of easily constructing a redundant uninterruptible power supply for obtaining a highly reliable uninterruptible power supply. The purpose is to do.

[0009]

In order to achieve the above object, the present invention obtains a DC voltage from an AC voltage, backs up this DC voltage with a battery, and then converts it into an AC voltage of a constant voltage constant frequency again. First and second UPS to output,
AC power is supplied to the first and second UPS in parallel,
A first operation mode in which each AC output is supplied to each load, and a second operation mode in which the first and second UPS are connected in cascade to supply the AC output to one load. A switching means is provided.

[0010]

When the first operation mode is set by the operation mode switching means, the first and second UPS supply the AC output to the two loads as the normal uninterruptible power supply. Further, if the second operation mode is set by the operation mode switching means, the first and second UPS are cascade-connected and have redundancy, and the AC output thereof is used as a highly reliable uninterruptible power supply for one load. Supply to.

[0011]

FIG. 1 shows a first embodiment of the uninterruptible power supply system of the present invention. In FIG. 1, UPSs 11 and 12 are equivalent to the conventional uninterruptible power supply device shown in FIG. The switches 13 to 15 are commands S13 to S13 from the switching control circuit 16.
It is opened and closed by S15. The mode setting circuit 17 determines the open / closed state of each of the switches 13 to 15 and sets the operation mode of the uninterruptible power supply.

The mode setter 17 has a first mode setting and a second mode setting, and switches 13 and 1 in the first mode.
4 is closed and the switch 15 is opened, and the AC outputs 3A and 3B of the UPS 11 and 12 are supplied to the load similarly to a normal uninterruptible power supply. When the mode setter 17 is set to the second mode, the switches 13 and 14 are opened, the switch 15 is closed, and UP
S11 and UPS12 are vertically connected and only AC output 3A is output. The AC output 3A in this case can be supplied as an AC power supply having the same high reliability as that of the parallel redundant uninterruptible power supply. In addition, the selection of the mode setting 17 is
The normal mode may be set to the first mode, and the UPS 12 may be switched to the second mode when an abnormality occurs. In this case, the AC output of the UPS 11 is the switch 15 and the UPS 1
An AC output 3A is obtained via a bypass circuit inside 2.

A second embodiment of the uninterruptible power supply of the present invention is shown in FIG. In FIG. 2, a load device 20A is an important load device such as a host computer and a magnetic disk, and a load device 20B is a normal load device such as a client distributed terminal, a printer, and a magnetic tape drive. The interface 18 has a communication line 21 for exchanging information with the load device 20A, and sets the first mode and the second mode based on the information. A communication line 22 for exchanging information is also provided between the load devices 20A and 20B. In such a configuration, when a power failure occurs in the AC power supply 2, the load device 20A recognizes the occurrence of the power failure via the communication line 21 and instructs the load device 20B to stop the work. Upon confirming the end of work, the load device 20A transmits a switching command from the first mode to the second mode via the communication line 21 and the interface 18. As a result, the switches 13 and 14 are opened and the switch 15 is closed.

According to this embodiment, in the event of a power failure, the work is stopped at a place well separated from the normal load device,
After that, since the UPSs that are no longer needed are connected in cascade to support the power supply of the important load, the backup operation time can be lengthened, and a rational and economical uninterruptible power supply can be provided.

[0015]

According to the present invention, a normal uninterruptible power supply and a highly reliable uninterruptible power supply with redundancy can be switched and used, and a rational system can be constructed.
It is possible to provide an economical general-purpose uninterruptible power supply.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a first embodiment of an uninterruptible power supply system according to the present invention.

FIG. 2 is a configuration diagram of a second embodiment of the uninterruptible power supply device of the present invention.

FIG. 3 is a configuration diagram of a conventional single-unit bypass type uninterruptible power supply device.

FIG. 4 is a configuration diagram of a conventional parallel redundant uninterruptible power supply device.

[Explanation of symbols]

 11, 12 ... Single unit bypass type uninterruptible power supply (UPS) 13 to 15 ... Switch 16 ... Switching control circuit 17 ... Mode setting circuit 18 ... Interface 20A ... (Important) load device 20B ... (Normal) load device

Claims (1)

[Claims] 1. A first and a second UPS for obtaining a DC voltage from an AC voltage, backing up the DC voltage with a battery, and then converting the AC voltage into a constant voltage constant frequency AC voltage and outputting the AC voltage.
AC power is supplied to the first and second UPS in parallel,
A first operation mode in which each AC output is supplied to each load, and a second operation mode in which the first and second UPS are connected in cascade to supply the AC output to one load. An uninterruptible power supply device characterized by comprising switching means.