JPH06311672A - Uninterruptible power-supply device - Google Patents

Abstract

PURPOSE:To repair the fault of a rectifier with time to spare. CONSTITUTION:While a device is normal and it is receiving commercial power- supply power, the commercial power-supply power is rectified by a rectifier 13 and converted into an alternating current by an inverter 14, and the laternating current is supplied to a load 17 (Fig. 1A). When the device is normal and a service interruption is caused, the direct current of a storage battery 18 is supplied to the inverter 14 and converted into an alternating current, and the alternating current is supplied to the load (Fig. 1B). When the device becomes faulty, the commercial power-supply power is supplied directly to the load 17 through a bypass 24 (Fig. 1C). When a service interruption is caused in this state, the direct current of the storage battery 18 is converted into an alternating current by the inverter 14, and the alternating current is supplied to the load (Fig. 1D). Consequently, as compared with a case where the rectifier becomes faulty and the output of the storage battery 18 is converted immediately by the inverter 14 and supplied to the load, it is not required to repair the rectifier in haste.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an uninterruptible power supply system of a type having a circuit for bypassing commercial power and always supplying power to a load through an inverter.

[0002]

2. Description of the Related Art A conventional uninterruptible power supply of this type is shown in FIG.
Shown in. In FIG. 2A, the input terminal 11 of the uninterruptible power supply device
Is connected to the commercial power supply 12, and this input terminal is connected to the rectifier 13.
AC power is rectified and supplied to the inverter 14. The output of the inverter 14 is supplied to the load 17 through the switch 15 and the output terminal 16. Further, the commercial AC power from the terminal 11 is supplied to the storage battery 1 through the charger 19.
8 is always charged. The output side of the storage battery 18 is connected to the input side of the inverter 14 through the switch 21. A bypass 24 is formed between the input terminal 11 and the output terminal 16 via the switch 23.

In this uninterruptible power supply system, when the device itself is normal and receives the AC power of the commercial power supply 12 (hereinafter referred to as receiving commercial power), the commercial power supply is as shown by the solid line in FIG. 3A. AC power from 12 is rectifier 1
3 is rectified, the rectified output is converted into alternating current by the inverter 14, and the alternating current power is supplied to the load 17 through the switch 15. In this way, the power supply power is supplied to the load 17.

When the AC power from the commercial power supply 12 is cut off in a normal state of this uninterruptible power supply, that is, when there is a power failure, the switch 21 is turned on to continuously charge the battery as shown by the solid line in FIG. 3B. DC power is supplied from the storage battery 18 to the inverter 14, and AC power from the inverter 14 is supplied to the load 17 through the switch 15.
Is supplied to.

If the uninterruptible power supply fails while receiving commercial power, that is, if the rectifier 13 fails, the switch 21 is turned on and the storage battery 18 is turned on as shown by the solid line in FIG. 3C.
DC power is supplied to the inverter 14, and AC power is supplied to the load 17 from the inverter 14. When the capacity of the storage battery 18 becomes less than or equal to a predetermined value in a failure state of this device, FIG.
As indicated by the solid line, the switch 23 is turned on, and the commercial power source power is supplied to the load 17 through the bypass 24.

By the way, as shown in FIG. 2B, the rectifier 13 is constructed by connecting a smoothing circuit 27 to the output side of a full-wave rectifier circuit in which a diode 26 is bridge-connected. Fuses 31 and 32 are provided on the input side and the output side, respectively. Alternatively, as shown in FIG. 2C, a high-speed switching element 33 such as an IGBT is bridge-connected, and a capacitor 34 is connected to the output side thereof, that is, between a pair of opposing bridge connection points, and another pair of other The bridge input side is between the bridge connection points, and commercial power is supplied to this. The rectifier of FIG. 2C is an active rectifier circuit and has substantially the same configuration as the inverter 14, and the switching element of one opposing arm of the bridge and the switching element of the other opposing arm are alternately turned on to input the commercial AC current. Electric power is full-wave rectified.

In the uninterruptible power supply device shown in the prior art, the power is supplied to the load through the inverter 14 even when the power supply is operating normally and the commercial power supply is being charged. Power is supplied to the load via the inverter 14, that is, it is always operated via the inverter 14 regardless of whether or not there is a power failure, and its output is supplied to the load. .

[0008]

In the prior art, when the rectifier 13 fails while receiving commercial power, the storage battery 18 drives the inverter 14 as described above, and the power capacity of the storage battery 18 is not so large. Therefore, when such an operating state passes for about 5 to 10 minutes, the storage battery 18 cannot supply sufficient electric power, and in this state, commercial power is directly supplied to the load 17 through the side path 24 to issue an alarm. The operation of the inverter 14 is stopped. Therefore, in this state, when the power failure occurs, the storage battery 18 is discharged, so that power cannot be supplied to the load 17 and the function as the uninterruptible power supply cannot be achieved. It will have a significant impact. Further, because of such a relationship, it is necessary to repair the failure of the rectifier 13 within a short time when the capacity of the storage battery 18 will not be lost if the rectifier 13 fails, and repair personnel will be able to immediately make such an emergency repair. It was hard to keep him waiting.

[0009]

According to the present invention, when a failure of a rectifier is detected, the failure detection signal disconnects the connection between the rectifier and the inverter, and switches from the constant inverter feeding operation mode to the inverter standby operation mode. .

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The hardware configuration of the uninterruptible power supply of the present invention is almost the same as that of the conventional device shown in FIG. 2A. The separating means 41 is inserted between the two, and there are differences in the operation in various states as shown in FIG. That is, while this uninterruptible power supply is normal and receiving commercial power, the commercial power is rectified by the rectifier 13 as shown by the solid line in FIG. 1A, and the rectified output is converted into AC power by the inverter 14 and is supplied to the load 17. Supplied.

Further, when the uninterruptible power supply is in a normal state, the commercial power supply power is cut off, that is, when a power failure occurs.
As indicated by the solid line, the switch 21 is turned on, and the DC power of the storage battery 18 is supplied to the inverter 14, thereby being converted into AC power and supplied to the load 17. The states shown in FIGS. 1A and 1B are the same as in the conventional case. However, when the rectifier 13 fails, the rectifier 13 is disconnected from the inverter 14 by the disconnecting means 41 and the switch 23 is turned on while receiving the commercial power, as shown by the solid line in FIG. The commercial power source power is directly supplied to the load 17. When a power failure occurs in this state, the switches 15 and 21 are turned on as shown by the solid line in FIG. 1D, and the DC power from the storage battery 18 is converted into AC power by the inverter 14 and supplied to the load 17. Although the inverter 14 does not operate in the state of FIG. 1C, its control circuit operates in synchronism with the commercial power supply power. The AC power can be supplied from the inverter 14 to the load 17 in synchronization with the commercial power supply. That is, when the rectifier 13 fails, the commercial power is supplied to the load while the commercial power is being received, the inverter 14 is brought into a stopped state, that is, a standby state, and the inverter is operated only after a power failure.
That is, when the rectifier 13 is normal, the inverter power supply operation is always performed, but when the rectifier 13 fails, the inverter 14 is in a standby mode. When this inverter standby operation mode is entered, a warning is issued that the device is out of order, and the problem is repaired. The failure of the rectifier 13 is due to an auxiliary contact of a breaker inserted in series on the output side of the rectifier 13, or an overvoltage detection relay and an undervoltage detection relay are provided on the output side of the rectifier 13 to detect an abnormal voltage. I'll do it.

[0012]

As described above, according to the present invention,
If the rectifier 13 fails, the inverter standby operation mode is entered, so that even if the commercial power supply fails in that state, the power of the storage battery 18 can be converted by the inverter and supplied to the load 17. Therefore, power failure does not occur very often and does not extend for a long time. Therefore, when the rectifier 13 fails, it is not necessary to repair the rectifier 13 so urgently, and the repair staff is always on standby. Rectifier repair work can be performed according to the convenience of operation of the load system and the convenience of repair personnel without the need. While the rectifier is out of order, commercial power is directly supplied to the load, so the function of supplying a stable voltage to the load, which is one of the functions of the uninterruptible power supply, is lost. The first function of maintaining the power supply during a power failure, which is an essential function of, is not lost. In the past, the rectifier failed, and the inverter operation with the storage battery was also impossible due to the discharge of the storage battery, and there was no major impact that would result in a power outage while supplying commercial power directly to the load. .

Particularly, recently, the active rectifier shown in FIG. 2C has a large number of elements, and the failure rate is about twice as high as that of the rectifier shown in FIG. 2B. However, this active rectifier improves the power factor of the input AC power. Also, it tends to be used frequently because it exerts a great effect on suppression of low-order harmonics, but as described above, it is easy to fail, and if a failure occurs, the problems described above may occur. In this case, the present invention is more effective. However, even in the rectifier using the diode shown in FIG. 2B, there are still problems such as failure, and the present invention is similarly effective.

As shown in FIG. 2C, if the output side of the rectifier 13 is connected to the inverter 14 through the diode 36, and the rectifier 13 fails, the diode 36 causes the inverter 14 and the storage battery 18 to fail.
Will be separated. A fuse may be used in place of the diode 36 for preventing backflow. In other words, failure in such an active rectifier is
The switching element 33 is short-circuited and a large current flows, so that the fuse is melted and disconnected. Further, when the rectifier 13 fails and the operation mode becomes the inverter standby operation mode, it is preferable that the display indicating that is turned on.

[Brief description of drawings]

FIG. 1 is a diagram showing a power supply state to a load in various states according to an embodiment of the present invention.

FIG. 2 is a block diagram showing an uninterruptible power supply device of this type, and B and C are connection diagrams showing an example of a rectifier 13 thereof.

FIG. 3 is a diagram showing a state of current supply in various states in the conventional uninterruptible power supply.

Claims (1)

[Claims] 1. A constant inverter power supply type uninterruptible power supply device having a circuit for bypassing commercial power, failure detecting means for detecting a failure of a rectifier for supplying power to an inverter while receiving commercial power, and failure thereof. An uninterruptible power supply having means for disconnecting the rectifier from the inverter by a failure detection signal of the detection means, and means for shifting the operation of the uninterruptible power supply device from the constant inverter power supply mode to the inverter standby operation mode by the failure detection signal. apparatus.