JPH0564381A - Noninterruptible power source apparatus - Google Patents

Abstract

PURPOSE:To diagnose abnormality by detecting discharge of a storage battery caused by a failure such as of a rectifier during normal ac input and to prevent unnecessary discharge of the storage battery by switching to power supply from an ac reserve power source. CONSTITUTION:A DC-CT21 detects discharge current of a storage battery 2 by supplying dc power from the storage battery 2 to an inverter 4. Discharge current of the storage battery 2 detected by the DC-CT21 is inputted to an abnormality detector 22, which diagnoses abnormality by a predetermined or more time of duration of the discharge of the storage battery 2 in spite of normal ac input power source and gives abnormality detected signal to a switch control circuit 23. The switch control circuit 23 receives this abnormality detected signal and controls selector switches 7, 8 for nonhit switching from power supply by the inverter 4 to power supply by a reserve ac power source 6, thereby bringing the storage battery 2 and the inverter 4 into a nonload state. This process can continue supply to a load 9 and prevent discontinuity of unnecessary discharge of the storage battery 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a rectifier, an inverter,
The present invention relates to an uninterruptible power supply device configured by a non-interruptible switch that switches between a storage battery, an inverter output, and another standby AC power source without any interruption.

[0002]

2. Description of the Related Art Conventionally, an uninterruptible power supply system has been widely used as an important load power source for a computer system or the like, which supplies uninterrupted AC power by inputting DC power from a storage battery even when a commercial AC power source fails. There is.

FIG. 2 is a block diagram showing an example of an uninterruptible power supply device. In the figure, 1 is an AC input power source such as a commercial AC power source, 2 is a storage battery, 3 is a rectifier that converts the AC input into DC and charges the storage battery 2, and 4 is an inverter.
5 is an AC filter for improving the rectangular wave output of the inverter 4 into a sine wave, 6 is a backup AC power supply, 7 and 8 are semiconductor changeover switches (thyristor switches), and 9 is a load. Power is constantly supplied to the load 9 by the inverter 4 via the AC filter 5 and the changeover switch 7, and is switched from the changeover switch 7 to the changeover switch 8 without interruption when the inverter 4 fails or when the maintenance of the device is performed. Power is supplied from the backup AC power supply 6, and after recovery from a failure or after completion of maintenance and inspection, the changeover switch is switched to the inverter 4 again so that power can be continuously supplied to the load 9.

[0004]

However, in the uninterruptible power supply system as described above, the AC input power supply 1 is normal even if the AC input power supply 1 is normal due to a failure of the control circuit of the rectifier 3 not shown. When the DC output is not supplied to the inverter 4, the DC power is supplied from the storage battery 2 to the inverter 4.
Automatically supplied to. That is, the storage battery 2 causes unnecessary discharge even though the AC input power supply 1 is not a power failure. If this state continues, the storage battery 2 is discharged, and the next AC input power failure or There is a possibility that the power failure compensation by the storage battery 2 may be impossible or insufficient with respect to the instantaneous voltage drop.

Therefore, an object of the present invention is made in view of the above-mentioned point, and an uninterruptible power supply device for preventing an unnecessary discharge of a storage battery caused by a failure of a rectifier and for diagnosing an abnormality. To provide.

[0006]

In order to achieve the above-mentioned object, the present invention provides an uninterruptible power supply device provided with an uninterruptible power switch for switching the inverter output and a standby AC power supply without interruption. Despite the normality of the input power supply, if the storage battery is used as the input of the inverter and continues to operate for a predetermined time or over a predetermined amount of power, it will be diagnosed as abnormal and a command to switch to power supply by the standby AC power supply with a non-interruptible switch is issued. I just provided a means to put it out.

[0007]

[Operation] In the uninterruptible power supply having such a configuration,
When the AC input is normal, the discharge of the storage battery caused by the failure of the rectifier or the like is detected to diagnose the abnormality and switch the power supply to the AC standby power supply to prevent unnecessary discharge of the storage battery.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. In FIG. 1, the same parts as those in FIG. 2 are designated by the same reference numerals, and the description thereof will be omitted. Here, different points will be described. In FIG. 1, 21 is a direct current transformer (hereinafter referred to as DC-CT) that detects the discharge current of the storage battery 2, and 22 is the storage battery 2 that is detected by the DC-CT 21 when the AC input is normal.
Of the abnormality detector for diagnosing the abnormality when the discharge of No. 2 continues for a predetermined time or longer.
8 is a switching control circuit that controls to switch on 8 without interruption.

In the embodiment shown in FIG. 1, for example, when the AC input power supply 1 is normal and the DC output of the rectifier 3 cannot be supplied due to a failure of a control circuit (not shown) of the rectifier 3, the inverter 2 is operated by the storage battery 2. DC power is supplied to 4. By supplying DC power from the storage battery 2 to the inverter 4, the discharge current of the storage battery 2 is detected by the DC-CT 21. Storage battery 2 detected by DC-CT21
Of the discharge current is input to the abnormality detector 22, and the abnormality detector 2
2 is a storage battery 2 even though the AC input power source 1 is normal.
When the discharge is continued for a predetermined time or longer, it is diagnosed as an abnormality and an abnormality detection signal is given to the switching control circuit 23. Upon receiving this abnormality detection signal, the changeover control circuit 23 receives the changeover switches 7 and 8
Is controlled so as to switch from the power supply by the inverter 4 to the power supply by the standby AC power supply 6 without interruption, and the storage battery 2 and the inverter are controlled.
The switch 4 is in an unloaded state. As a device diagnosed as abnormal, it is sufficient to stop the inverter 4 to prevent unnecessary discharge of the storage battery 2. However, regarding the protective operation and the explanation of the rectifier section diagnosis procedure that is subsequently performed, It is omitted here.

By detecting the unnecessary discharge of the storage battery 2 in this way, the abnormality is diagnosed and the power is supplied from the auxiliary AC power source 6, so that the power supply to the load 9 is continued and the unnecessary discharge of the storage battery 2 is prevented from continuing. can do. Also, as the DC-CT21 for detecting the discharge current, an inexpensive hole CT using a hole element can be applied in recent years, and there is no practical problem in terms of economy.

In the embodiment of FIG. 1, the abnormality is diagnosed only by the discharge current of the storage battery.
The amount of electric power corresponding to H may be detected as a time integrated value of (current) × (voltage), and an abnormality may be diagnosed when a predetermined amount is exceeded.

[0012]

As described above, according to the present invention, the unnecessary discharge of the storage battery due to the abnormal operation during the normal operation of the AC input power source is predicted and diagnosed, and the original backup ability against a power failure or an instantaneous voltage drop is not impaired. It is possible to provide a highly reliable uninterruptible power supply device.

[Brief description of drawings]

FIG. 1 is a block diagram of an uninterruptible power supply device showing an embodiment of the present invention.

FIG. 2 is a block diagram of a conventional uninterruptible power supply.

[Explanation of symbols]

1 ... AC input power supply 2 ...
Storage battery 3 ... Charger 4 ...
Inverter 5 ... AC filter 6 ...
Spare AC power supply 7, 8 ... Changeover switch 9 ...
Load 21 ... DC-CT 22 ...
Abnormality detector 23 ... Switching control circuit

Claims (1)

[Claims] 1. A rectifier for converting an alternating current supplied from a commercial alternating current power source into a direct current, an inverter for converting a direct current output of the rectifier into an alternating current and feeding the alternating current output to a load, and a power failure of the commercial alternating current power source. Alternatively, a storage battery that supplies direct current to the inverter when there is an instantaneous voltage drop, and a power supply to the load by switching from the output of the inverter to the standby AC power supply without interruption during failure or inspection of the inverter or rectifier. In an uninterruptible power supply composed of an uninterruptible switch for
When the commercial AC power supply is normal, the storage battery is replaced with the inverter.
A means for diagnosing an abnormality when the operation is continued for a predetermined time or over a predetermined amount of electric power as an input of the data, and when the abnormality is diagnosed, the power supply from the standby AC power supply is switched to without interruption. Power supply.