JPH077873A - Uninterruptive power supply equipment - Google Patents

Abstract

PURPOSE:To permit feeding to a load even though a power service interruption occurs during direct supply of commercial power due to a fault in an inverter. CONSTITUTION:In an uninterruptive power supply equipment of continuous operation inverter feed type, if an inverter 14 has a fault, then switches 15, 21 and 44 are turned off, switches 23 and 41 are turned on, AC power of a commercial power supply 12 is directly transmitted to a load 17 through a bypass 24, and a battery 18 is charged through a charger 19. If a power service interruption occurs under the condition stated above, an active rectifying circuit 13 operates as inverter; a switch 41 is turned off and a switch 21 is turned on; and DC power from the battery 18 is converted into AC power by the rectifying circuit 13 and is then supplied to a load 17 through the bypass 24.

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 which comprises a circuit for bypassing commercial power and an active rectification circuit, and which constantly supplies 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 the input terminal 1
1 is connected to the rectifier circuit 13, and the AC power from the commercial power source 12 is rectified by the rectifier circuit 13 and supplied to the inverter 14. The output of the inverter 14 is the AC switch 15
Through the output terminal 16 to the load 17. Further, the commercial AC power from the input terminal 11 is supplied to the charger 19
The storage battery 18 is constantly charged through the. The output side of the storage battery 18 is connected to the input side of the inverter 14 through the DC switch 21. A bypass 24 is formed between the input terminal 11 and the output terminal 16 via the AC 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. The AC power from 12 is rectified by the rectifier circuit 13, the rectified output is converted into AC by the inverter 14, and the AC 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, is converted into AC power by the inverter 14, and the converted AC power is supplied to the load 17 through the switch 15. In this way, the power source can be switched from the commercial power source 12 to the storage battery 18 at a high speed.

If the uninterruptible power supply unit fails while receiving commercial power, that is, if the inverter 14 fails, for example, as shown in FIG.
As indicated by a solid line in C, the switch 23 is turned on to supply commercial power to the load 17 through the bypass 24. By the way, as the rectifier circuit 13, as shown in FIG.
A high-speed switching element 33 such as is connected to a bridge, and an output side thereof, that is, a capacitor 34 is connected between a pair of opposing bridge connection points, and another pair of different bridge connection points is connected for active rectification. It is used as a bridge input side through a low-pass filter 35 that also serves as a reactor and does not output noise to the outside, and commercial power source power is supplied to this input side. The active rectifier circuit shown in FIG. 2B has almost the same configuration as the inverter 14,
The inverter 14 has the circuit configuration shown in FIG. 2C. That is, between the pair of opposing bridge connection points of the bridge connection of the high-speed switching element 36 is the input side, and between the other pair of the opposing bridge connection points is the output side via the low-pass filter 37. The switching element of one opposing arm and the switching element of the other opposing arm of the bridge are alternately turned on, and the DC power of the storage battery is converted into AC power. On the other hand, in the active rectifier circuit 13, the switching element of one opposing arm and the switching element of the other opposing arm of the bridge are alternately turned on, and the input commercial AC power is full-wave rectified.

In the uninterruptible power supply device shown in the related art, the power is supplied to the load through the inverter 14 even when the commercial power supply is operating normally and is charged, and even when a power failure occurs. 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. .

A fuse or breaker 38 is inserted in series on each of the input side and the output side of the rectifier circuit 13,
Further, fuses or breakers 39 are inserted in series on the input side and the output side of the inverter 14, respectively. A backflow prevention diode may be used instead of the fuse 38 on the output side of the rectifier circuit 13.

[0008]

As described above, in the conventional uninterruptible power supply, when the inverter 14 fails, commercial AC power is directly sent to the load 17 as shown in FIG. 3C. If a power failure occurs in this state, load 1
7 cannot be supplied with electric power, which may cause a serious problem. In this way, when the inverter is out of order, the original function of the uninterruptible power supply is lost. Therefore, when the inverter 14 failed, it was necessary to immediately repair it.

[0009]

According to the present invention, the commercial power supply and the charger and the rectifier circuit can be cut off by the input cutoff means, and the failure detection means for detecting the failure of the inverter is provided. When a failure is detected by the failure detecting means, the side output is activated by the detection output and the commercial power is directly sent.If a power failure occurs in this state, the input cutoff means is cut off and the inverter is disconnected. , The rectifier circuit is operated as an inverter, and the storage battery power is supplied to it. In other words, if the inverter fails, the commercial power is directly sent and the inverter standby mode in which the rectifier circuit is used as the inverter is set.

[0010]

FIG. 1A shows an embodiment of the present invention, in which parts corresponding to those in FIG. 2A are designated by the same reference numerals. In this embodiment, an AC switch 41 is inserted in series between the connection point of the bypass 24 and the filter 35 and the connection point of the input terminal 11 and the charger 19, so that the rectifier circuit 13, the commercial power supply 12 and the charger 19 are connected. The input side of the can be cut off.
Further, an overvoltage detection circuit 42 and an undervoltage detection circuit 43 are connected to the output side of the inverter 14 so that a failure of the inverter 14 can be detected and output. This detection output is input to a control unit (not shown).
Further, a DC switch 44 is inserted in series between the connection point of the rectifier circuit 13 and the DC switch 21 and the input side of the inverter 14.

In this configuration, the AC switches 15 and 41 and the DC switch 44 are turned on and the DC switch 21 and the AC switch 23 are turned off while the device is receiving normal commercial AC power in a normal state, as shown in FIG. 3A. As described above, the commercial AC power is rectified, the rectified output is converted into AC power by the inverter 14, and the commercial power is supplied to the load 17.
Charge to 8. When a power failure occurs in this state, the DC switch 21 is turned ON, the AC switches 23 and 41 are turned OFF with the AC switch 15 kept ON, and the DC power of the storage battery 18 is AC-converted by the inverter 14 as shown in FIG. 3B. The electric power is supplied to the load 17. That is, it operates in the continuous operation inverter power supply mode as in the conventional case.

When the inverter 14 fails, the AC switches 23 and 41 are turned on, the AC switch 15 and the DC switches 21 and 44 are turned off, and commercial AC power is supplied to the load 17 through the bypass 24 as shown by the solid line in FIG. 1B. The battery is directly sent to and the storage battery 18 is charged. That is, the state is the same as the state shown in FIG. 3C of the related art. However, in this state, the rectifier circuit 13 is shifted to the inverter standby mode in which it operates as an inverter.

Therefore, when a power failure occurs in this state of direct transmission of commercial power, the AC switch 41 is also turned off and the DC switch 21
Is turned on and the rectifying circuit 13 is operated as an inverter. Therefore, as shown by the solid line in FIG.
Is converted into AC power by the rectifier circuit 13 and supplied to the load 17 through the bypass 24. At this time, filter 3
The action of 7 is performed by the filter 35. Further, this AC power is blocked from going to the commercial power source 12 and the charger 19 side by the OFF of the AC switch 41, and the DC current of the storage battery 18 is blocked from flowing to the inverter 14 side by the OFF of the DC switch 44. .

The switch 44 may be turned off not in the state of FIG. 1B but in the state of FIG. 1C. As shown by the dotted line in FIG. 1A, the connection point of the AC switch 41 and the filter 35 and the input side of the charger 19 are directly connected to each other, and the connection between the input side of the charger 19 and the input terminal 11 is removed. It is also possible to use a controllable device as, and to stop the charging of the charger 19 in the state of FIG. Further, as shown by a dotted line in FIG. 1A, a capacitor 45 is connected to the output terminal 16 so that the filters 35, 3
The capacitors 7 and 7 may be omitted and the capacitors 45 may be used in common. Normally, the choke coil of the filter 35 is smaller than the choke coil of the filter 37. However, when the rectifier circuit 13 is operated as an inverter, the filter 35 has a smaller distortion.
It is advisable to use a choke coil having the same characteristics as that of the filter 37.

[0015]

As described above, according to the present invention, when the inverter 14 is out of order, the inverter standby operation mode in which the rectifier circuit 13 acts as an inverter is set, and when a power failure occurs in this state, the DC power of the storage battery 18 is generated. Is converted into AC power by the rectifier circuit 13 and is supplied to the load through the side path, the first function as the uninterruptible power supply is obtained, and there is no fear of a serious accident.

Further, even if a power failure occurs during the inverter failure, the AC power supply to the load is not interrupted, so that the failed inverter 14 does not need to be repaired so much and the load system can be operated. The repair work may be carried out according to the convenience of the customer and the convenience of the repair staff.

[Brief description of drawings]

1A is a block diagram schematically showing an embodiment of the present invention, FIG. 1B is a diagram showing a power supply state to a load when an inverter fails during commercial power reception, and C is a load diagram when a power failure occurs during an inverter failure. It is a figure which shows a power feeding state.

2 is a block diagram schematically showing a conventional uninterruptible power supply device, B is a circuit diagram showing a specific configuration of an active rectifier circuit 13, and C is a circuit diagram showing a specific configuration of an inverter 14. FIG.

FIG. 3A is a diagram showing power supply to a load during commercial power reception in a device normal state in the conventional uninterruptible power supply system shown in FIG. 2A, and B is power supply to a load during a power failure in a device normal state. FIG. 3C is a diagram showing power supply to the load of commercial power when the inverter fails.

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[Procedure amendment]

[Submission date] October 15, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 1

[Correction method] Change

[Correction content]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0001

[Correction method] Change

[Correction content]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an uninterruptible power supply system of a type which comprises a circuit for bypassing commercial power and an active rectifier circuit, and which constantly supplies power to a load through an inverter.

Claims (1)

[Claims] 1. In an uninterruptible power supply system of active current type, constant operation inverter feeding type, which has a circuit for bypassing commercial AC power, an input cutoff capable of cutting off a commercial power source, a charger and a rectifier circuit. Means, a failure detection means for detecting a failure of the inverter, a means for enabling the bypass by the detection output of the failure detection means, the input cutoff means in a cutoff state at the time of a power failure at the time of the inverter failure, and An uninterruptible power supply device comprising: means for disconnecting an inverter, operating the rectifier circuit as an inverter, and supplying storage battery power thereto.