JP3446773B2 - Uninterruptible power system - Google Patents

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 unit which constantly and continuously supplies AC power to a load.

[0002]

2. Description of the Related Art Some uninterruptible power supplies have an emergency generator in addition to a commercial power supply. This type of conventional uninterruptible power supply is equipped with a changeover switch that switches between a commercial power supply and a generator, rectifies the AC power input to the uninterruptible power supply, converts it to DC power, and charges the storage battery floatingly. At the same time, DC power is always converted back to AC power by an inverter and supplied to the load.

[0003]

In the above-mentioned conventional uninterruptible power supply, depending on the function of the generator, the output voltage of the generator may be distorted or the frequency may vary greatly, and the AC output from the generator may be output to the load as it is. In some cases, the output of the generator is once converted into DC power, and by the inverter being converted back into AC power, good AC power can be supplied. However, if the inverter is always operated continuously, power loss becomes large and a cooling structure including a cooler for cooling the lost heat becomes large. In addition, the rectifier requires a sufficient capacity to secure the rated output capacity of the inverter, which causes a problem of large size. If an attempt is made to reduce the size of the cooling structure, forced air cooling by an electric fan is always required, which causes a problem such as noise. For this reason, the conventional uninterruptible power supply has a drawback that the device becomes large and the price of the device becomes high.

An object of the present invention is to provide an uninterruptible power supply device which can solve the above problems.

Another object of the present invention is to provide an uninterruptible power supply which does not cause a battery to be overdischarged.

Another object of the present invention is to provide an uninterruptible power supply which can automatically switch the output of a battery and the output of a rectifier for rectifying the output of another AC power source with a simple structure.

[0007]

An uninterruptible power supply system of the present invention for solving the above problems will be described with reference to the reference numerals attached to the drawings of the embodiments. The uninterruptible power supply of the present invention uses the DC power obtained by rectifying the AC power of the commercial power supply 1 to the battery 6
The battery charging circuit 5 that charges the battery, the inverter 8 that converts the output of the battery 6 into AC power and outputs the AC power, and the state of the AC power supplied from the commercial power supply 1 are determined. It is intended for an uninterruptible power supply device that includes an AC power switching device 13 that outputs the load 14 to the load 14 and operates the inverter 8 to output the output of the inverter to the load when the commercial power supply 1 is abnormal. In the present invention, the rectifier 7 that rectifies the AC power that is input from the AC power supply 2 that is different from the commercial power supply 1, and the output of the battery 6 that is output from the inverter 8 when the output voltage of the rectifier is lower than the terminal voltage of the battery 6. And a DC power switching circuit 10 for supplying the output of the rectifier 7 to the inverter 8 when the output voltage of the rectifier 7 becomes equal to or higher than the terminal voltage of the battery 6.

The commercial power source 1 and another AC power source 2 such as a generator may be switched by a changeover switch. If this changeover switch is operated in conjunction with the operation of the AC power switching device 13, the commercial power supply 1 and another AC power supply 2 are automatically switched. Further, it is preferable to automatically start another AC power source 2 such as a generator in conjunction with the detection of the abnormality of the commercial power source. However, it goes without saying that the AC power supply 2 may be activated by a manual operation.

When the commercial power source 1 and the generator 2 are switched using the changeover switch, the AC power switching device determines the state of the AC power supplied through the changeover switch, and supplies the AC power when the supplied AC power is normal. It is preferable that the AC power to be output is output from the output terminal and the inverter is operated to output the output of the inverter from the output terminal when the supplied AC power is abnormal. The battery 6 is used as a DC power source for the inverter until AC power is input from another AC power source 2 such as a generator.

The DC power switching circuit 10 is connected to the battery 6
And a first diode 9a disposed between the inverter 8 and the inverter 8 and a first diode 9a disposed between the rectifier 7 and the inverter 8 such that the anode is oriented toward the rectifier 7 side. With the second diode 9b, it is possible to switch the DC power supplied to the inverter 8 with a simple circuit without using a voltage sensor, a switching circuit, or the like.

[0011]

The uninterruptible power supply system of the present invention supplies the AC power of the commercial power source 1 to the load 14 when the commercial power source 1 is normal. When an abnormality occurs in the commercial power supply 1, the AC power switching device 13 operates to operate the inverter 8 to first convert the DC power of the battery 6 into AC power and supply it to the load 14. And an AC power supply 2 different from the commercial power supply 1 such as a generator
When the output power of the rectifier 7 for rectifying the AC power from the battery becomes equal to or higher than the terminal voltage of the battery 6, the input DC power of the inverter 8 is switched from the output of the battery 6 to the output of the rectifier 7 by the operation of the DC power switching circuit 10. . That is, in the present invention, since the inverter 8 operates only when the commercial power supply 1 is abnormal, there is substantially no power loss at all times, and it is not necessary to provide cooling equipment such as a cooling fan. Further, since the DC power switching circuit 10 is provided, the battery 6 is discharged only after the output of the commercial power supply 1 becomes abnormal until the output of another AC power supply 2 becomes normal. Therefore, the battery 6 will not be over-discharged even if the abnormality of the commercial power supply 1 is prolonged.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIG. In the figure, 1 is a commercial power source, 2 is a generator as another AC power source that is operated at the time of a power failure of the commercial power source 1 and outputs AC power, and 3 is an uninterruptible power supply device of this embodiment. 3a is an input terminal for commercial power supply power, 3b is an input terminal for generator output, 3c is an output terminal for outputting AC power to a load, and 14 is a load. 4 is an input terminal 3a and an output terminal 3
An electronic switch 5 is connected to the circuit c, 5 is a charging circuit including a rectifier, and 6 is a battery charged by the charging circuit 5. 7 is a rectifier that rectifies the AC power from the generator 2,
Reference numeral 8 is an inverter that converts DC power into AC power and outputs the AC power. Reference numeral 9a denotes a first diode in which the anode is connected to the positive electrode side of the battery 6, the cathode is connected to the input terminal side of the inverter 8, and 9b is the anode to the output terminal side of the rectifier 7, and the cathode to the input terminal side of the inverter 8. It is the second diode connected respectively. The above two diodes 9
A and 9b form a DC power switching circuit 10.

Reference numeral 11 designates an input terminal of the charging circuit 5 as an input terminal 3a.
Is a changeover switch that is connected to the side of and the side of the input terminal 3b. 12 is a step-down transformer, 13 is the presence or absence of abnormality of the commercial power supply 1 based on the output voltage of this transformer, and outputs a control signal to turn on / off the electronic switch 4 and start / stop the inverter 8, In addition, the AC power switching device controls switching of the changeover switch 11.

The operation of the power supply device of this embodiment will be described below.
When the commercial power supply 1 is normal, the electronic switch 4 is turned on by the control signal from the AC power switching device 13, and the AC power of the commercial power supply 1 is supplied to the load 14. At this time, the inverter 8 is stopped by the control signal from the AC power switching device 13, the changeover switch 11 is turned on to the input terminal 3a side, and the battery 6 is charged through the charging circuit 5.

When the commercial power source 1 fails, the AC power switching device 13 detects this and turns off the electronic switch 4 by a control signal and simultaneously operates the inverter 8. Further, the changeover switch 11 is switched to the input terminal 3b side by a control signal from the AC power switching device 13. In this case, the inverter 8 first converts the DC power from the battery 6 into AC power and supplies it to the load 14. On the other hand, when the commercial power supply 1 is stopped, the generator 2 is operated as a backup power supply.
In this case, the inverter 8 receives the DC power of the battery 6 and outputs the AC power until the output of the generator 2 gradually increases and the output voltage becomes a normal value. Then, when the output voltage of the generator 2 becomes a normal value and the output DC voltage from the rectifier 7 exceeds the voltage of the battery 6, the diodes 9a and 9b connected as shown in FIG. Instead of the DC power, the DC power from the rectifier 6 is input to the inverter 8 and converted into AC power for output. in this case,
The changeover switch 11 is operated by the changeover device 13 so that the input terminal 3b
The battery 6 is switched to the ON side, and the battery 6 is charged by the output of the generator 2 through the charging circuit 5.

That is, in the present embodiment, the inverter 8
Is operated only when the commercial power supply 1 fails, and after the commercial power supply 1 fails until the output of the generator 2 becomes normal, the DC power of the battery 6 is input to the inverter 8 and the output of the generator 2 is normal. After that, the DC power from the rectifier 7 is input to the inverter 8 and converted into AC power for output. When the commercial power source 1 is restored, the AC power switching device 13
By this action, the electronic switch 4 is turned on, the inverter 8 is stopped, and the power of the commercial power supply 1 is supplied to the load 14.
Further, the changeover switch 11 is changed over to the input terminal 3a side, and the storage battery 6 is charged. Generator 2 is commercial power supply 1
The operation will be stopped when the vehicle is restored.

FIG. 2 shows the circuit configuration of the second embodiment of the present invention. The present embodiment differs from the embodiment of FIG. 1 in the position of the changeover switch 11 ′ and the AC power switching device 1
3'is the configuration or operation. In the present embodiment, the changeover switch 11 'is arranged between the input terminal 3a and the commercial power supply 1. Further, the AC power switching device 13 'of this embodiment is
The state of the AC power supplied through the change-over switch 11 'is determined, the AC power supplied is output from the output terminal when the AC power supplied is normal, and the inverter 8 is operated when the AC power supplied is abnormal. The output of the inverter 8 is output from the output terminal 3c.

In the present embodiment, when an abnormality occurs in the commercial power source 1, the AC power switching device 13 'operates the inverter 8 by using the battery 6 as a power source and loads the inverter 8 in the load 14.
Supply the output of. When the generator 2 is started manually or automatically and the changeover switch 11 ′ is switched manually or automatically with the occurrence of an abnormality in the commercial power source 1, the AC power from the generator 2 is supplied to the charging circuit 5 and the rectifier 7. Supplied. The output of the generator 2 is not supplied to the load 14 until the generator 2 is started up and its output is above a certain level, that is, sufficiently established. That is, when the generator 2 is initially activated,
The inverter 8 operates using the battery 6 as a power source, and AC power is supplied to the load 14. When the voltage obtained by rectifying the output of the generator 2 by the rectifier 7 becomes higher than the voltage of the battery 6,
The inverter 8 operates using the output of the rectifier 7 as a power source and outputs AC power to the load 14. At this time, the battery 6 is charged by the output of the generator 2 through the changeover switch 11 ′ and the charging circuit 5. Then, when the output of the generator 2 is sufficiently established, the AC power switching device 13 ′ determines that the AC power supplied from the generator 2 has become normal, turns on the electronic switch 4, and operates the inverter 8. And the output of the generator 2 is passed through the electronic switch 4 to the load 14
Supply to. After that, AC power is supplied from the generator 2 to the load 14. Therefore, according to this embodiment, the operating time of the inverter 8 can be shortened as compared with the embodiment of FIG. After the generator 2 is started and the commercial power source is restored, the changeover switch 11 ′ is manually or automatically switched to supply AC power from the commercial power source 1 to the load 14. When the generator 2 is switched to the commercial power source 1, the inverter 6 is operated by using the battery 6 as a power source, so that the AC power supply to the load is not interrupted.

The constituent features of some of the inventions described in the specification of the present application will be described below.

(1) An input terminal to which AC power is supplied from a commercial power source, an output terminal for outputting AC power to a load, a battery, and a DC obtained by rectifying the AC power supplied through the input terminal. A battery charging circuit that charges the battery with electric power, an inverter that converts the output of the battery into AC power and outputs the AC power, a generator that generates AC power when the commercial power supply is abnormal, and a power supply from the commercial power supply. The changeover switch 11 for switching between the input of the AC power output from the generator and the input of the AC power output from the generator, and the state of the AC power supplied from the commercial power supply is determined, and when the AC power supplied from the commercial power supply is normal. AC power supplied from the commercial power source is output from the output terminal, and when the commercial power source is abnormal, the changeover switch 11 is switched to switch the generator. AC by operating the inverter inputs the AC power et outputted to an output of the inverter from the output terminal power switching device 13
An uninterruptible power supply device comprising: a rectifier 7 for rectifying AC power input from the generator 2, and an output voltage of the rectifier 7 of the battery 6 when the output voltage of the rectifier 7 is lower than a terminal voltage of the battery 6. An uninterruptible power supply comprising: a DC power switching circuit that supplies an output to the inverter, and supplies the output of the rectifier 7 to the inverter 8 when the output voltage of the rectifier 7 becomes equal to or higher than the terminal voltage of the battery. Power supply.

(2) The uninterruptible power supply device according to (1), wherein the AC power switching device 13 switches the changeover switch 11 so that the AC power is input from the commercial power supply when the commercial power supply becomes normal.

(3) The uninterruptible power supply according to the above (2), wherein the generator 2 is started and stopped in conjunction with a changeover switch 11 which is switched by a control signal from the AC power switching device 13. apparatus.

[0023]

As described above, according to the uninterruptible power supply system of the present invention, the commercial power source is always used, and when the commercial power source is abnormal, the inverter is operated to supply the AC power to the load. And when the commercial power supply is abnormal, the AC power input from the AC power supply different from the commercial power supply is rectified by the rectifier,
When the output voltage of the rectifier is lower than the voltage of the battery, the DC power of the battery is supplied to the inverter. When the output voltage of the rectifier becomes equal to or higher than the voltage of the battery, the output of the rectifier is supplied to the inverter and converted to AC power. As a result, the inverter is stopped during normal normal operation of the commercial power supply, and no power loss or heat generation due to this power loss occurs. Therefore, the operating cost of the power supply device can be significantly reduced, the heat dissipation mechanism of the inverter can be simplified, and the device can be relatively small and inexpensive, and can be noiseless at all times. Further, according to the present invention, since the DC power switching circuit is provided, the battery is discharged only after the abnormality of the output of the commercial power source occurs until the output of another AC power source becomes normal. The battery does not become over-discharged even if the power supply abnormality continues for a long time.

[Brief description of drawings]

FIG. 1 is a connection diagram showing a schematic configuration of an embodiment of the present invention.

FIG. 2 is a connection diagram showing a configuration outline of another embodiment of the present invention.

[Explanation of symbols]

1 Commercial power supply 2 generator 3 uninterruptible power supply 4 electronic switches 5 charging circuit 6 battery 7 Rectifier 8 inverter 9a, 9b diode 10 DC power switching circuit 11, 11 'selector switch 13, 13 'AC power switching device 14 load

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H02M 7/48 H02J 9/06

Claims (2)

(57) [Claims] 1. An input terminal to which AC power is supplied from a commercial power source, an output terminal for outputting AC power to a load, a battery, and DC power obtained by rectifying the AC power supplied through the input terminal. A battery charging circuit for charging the battery, an inverter that converts the output of the battery into AC power and outputs the AC power, and determines the state of the AC power supplied from the commercial power supply,
When the AC power supplied from the commercial power supply is normal, the AC power supplied from the commercial power supply is output from the output terminal, and when the commercial power supply is abnormal, the inverter is operated to output the output of the inverter. An uninterruptible power supply device comprising an AC power switching device to be output from a terminal, wherein a rectifier that rectifies AC power input from an AC generator different from the commercial power supply, and AC power of the commercial power supply. Switch the AC power of the generator
And a changeover switch to be given to the battery charging circuit, and when the output voltage of the rectifier is lower than the terminal voltage of the battery, the output of the battery is supplied to the inverter, and the output voltage of the rectifier is equal to or higher than the terminal voltage of the battery. A DC power switching circuit that supplies the output of the rectifier to the inverter , wherein the DC power switching circuit includes the battery and the inverter.
So that the anode faces the battery side
A first diode, the rectifier, and the diode.
So that the anode faces the rectifier between the converter and
Composed of a second diode arranged in
Uninterruptible power supply, characterized in that that. 2. A generator that generates AC power when a commercial power source is abnormal, an input terminal to which the AC power is supplied, an output terminal that outputs the AC power to a load, a battery, and a power supply through the input terminal. A battery charging circuit that charges the battery with the DC power obtained by rectifying the AC power, an inverter that converts the output of the battery into the AC power and outputs the AC power, and an AC power supplied from the commercial power supply. Judge the state,
When the AC power supplied from the commercial power source is normal
An AC power switching device that outputs the AC power supplied from the commercial power supply from the output terminal and operates the inverter to output the output of the inverter from the output terminal when the commercial power supply is abnormal. A power failure power supply device, wherein a rectifier that rectifies the AC power input from the generator, the AC power supplied from the commercial power source, and the generator
Line for switching the output AC power to supply power to the load
And a changeover switch applied to the battery charging circuit, and when the output voltage of the rectifier is lower than the terminal voltage of the battery, the output of the battery is supplied to the inverter, and the output voltage of the rectifier is equal to or higher than the terminal voltage of the battery. the output of the rectifier comprising a DC power switching circuit for supplying to said inverter, said DC power switching circuit, the said battery Invar
So that the anode faces the battery side
A first diode, the rectifier, and the diode.
So that the anode faces the rectifier between the converter and
Composed of a second diode arranged in
Uninterruptible power supply, characterized in that that.