JP2003070184A - Uninterruptible power supply system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an uninterruptible power supply at a low cost. SOLUTION: In the normal operation, a load feed is carried out by an UPS system 20a of a normal inverter feed system which comprises converter equipment 11a and inverter equipment 12a. In a trouble or a periodic check of the UPS system 20a, a UPS system 20c of a normal commercial feeding system which outputs directly the commercial electric power in the normal operation is used as a backup UPS system. The backup UPS system 20c dispenses a converter equipment by this constitution.

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 for supplying a constant-voltage constant-frequency AC power to a load even when a commercial power supply fails.

[0002]

2. Description of the Related Art Conventional uninterruptible power supply systems are often constructed by connecting a plurality of uninterruptible power supply devices of the same configuration in parallel in order to improve the reliability of power supply. However, in the case of the parallel connection configuration, since the outputs of all uninterruptible power supply devices are connected to one place, there is a commonly used part such as a direct transfer switching circuit, and the circuit of this common part is There was a problem that the whole system had to be stopped when checking. For this reason, in systems in which stoppage is not allowed even for a moment, the number of serial connection configurations is increasing.

FIG. 5 is a circuit diagram showing the configuration of a conventional uninterruptible power supply system having a serial connection configuration. The two uninterruptible power supplies 20a and 20b have the same configuration, and when they are connected in series, one uninterruptible power supply is out of order or inspected because the uninterruptible power supplies 20a and 20b do not have a common part. Even in the middle, the load can be supplied by the other uninterruptible power supply.

[0004]

In the uninterruptible power supply system of the serial connection configuration shown in the figure, the uninterruptible power supply 20b is a backup power supply, and the power supply path to the load 14 is AC during normal operation. It is cut off by the output breaker 9b, and the operation is no load. The uninterruptible power supply 20b performs load power supply when the uninterruptible power supply 20a fails or is being inspected.

Generally, uninterruptible power supplies are designed to be extremely reliable and have a very low probability of failure. Therefore, the uninterruptible power supply 20b substantially feeds the load only during the inspection of the uninterruptible power supply 20a.

The uninterruptible power supply 20a is inspected once a year,
If it is performed only for 4 hours, the operation rate of the load power supply of the uninterruptible power supply 20b is about 0.05%, and the operation rate of the uninterruptible power supply 20a is about 99.95%. As described above, it is problematic in terms of cost performance to adopt a device having the same reliability for the uninterruptible power supply device having a large difference in operation rate of load power supply.

The present invention has been made in view of the above, and an object of the present invention is to provide an inexpensive uninterruptible power supply system capable of constantly supplying power to a load even when the uninterruptible power supply unit fails or is inspected. To provide in.

[0008]

In order to achieve the above object, an uninterruptible power supply system according to the present invention according to claim 1 is a continuous inverter power supply type uninterruptible power supply for supplying AC power to a load during normal operation. When a failure occurs in the power supply device, a standby commercial power supply uninterruptible power supply device for backup, and a constant inverter power supply uninterruptible power supply device, switching means for switching to the continuous commercial power supply system uninterruptible power supply device,
It is characterized by having.

According to the present invention, as the backup uninterruptible power supply device, the continuous commercial power supply system device which outputs the commercial power supply as it is during the normal operation is used. The equipment can be eliminated and an uninterruptible power supply system can be realized at low cost.

According to a second aspect of the present invention, in the uninterruptible power supply system according to the first aspect, the input stage of the constant inverter power supply type uninterruptible power supply device and the output stage of the constant commercial power supply type uninterruptible power supply device. It is characterized by having an opening / closing means for opening and closing the connection with and a connecting means for connecting the output line of one of the two types of uninterruptible power supply and the load.

According to the present invention, when inspecting an uninterruptible power supply device of a constant inverter power supply system, an input stage of the uninterruptible power supply device of the constant inverter power supply system and an output stage of the uninterruptible power supply device of a constant commercial power supply system. The connection between the output line of the uninterruptible power supply system of the constant commercial power supply system and the load and the connection of the output line of the uninterruptible power supply system of the continuous inverter power supply system and the load can be released. As a result, the uninterruptible power supply system of the continuous inverter power supply system can be completely disconnected from the load power supply path, and safe inspection is possible while maintaining uninterrupted power supply.

The present invention according to claim 3 provides the invention according to claim 1 or 2.
In the uninterruptible power supply system described above, a storage battery is shared by the uninterruptible power supply device of the constant inverter power supply system and the uninterruptible power supply device of the constant commercial power supply system, and the uninterruptible power supply device of the continuous commercial power supply system is charged for a storage battery. It is characterized by not requiring a vessel.

According to the present invention, the uninterruptible power supply device of the constant inverter power supply system and the uninterruptible power supply device of the constant commercial power supply system share the storage battery so that the uninterruptible power supply device of the continuous commercial power supply system can be used as a charger. Is made unnecessary and an uninterruptible power supply system can be realized at low cost.

The present invention according to claim 4 provides the invention according to claim 1 or 2.
In the uninterruptible power supply system described above, a voltage compensator is used in place of the uninterruptible power supply device of the constant commercial power supply system.

According to the present invention, the voltage compensator is used in place of the uninterruptible power supply system of the continuous commercial power feeding system, so that the inverter device can be downsized and the uninterruptible power supply system can be realized at low cost. I am able to do it.

According to a fifth aspect of the present invention, in the uninterruptible power supply system according to the fourth aspect, a parallel operation by the uninterruptible power supply device of the constant inverter power feeding type and the voltage compensating device and a non-operation of the constant inverter power feeding type. Switching means for switching between isolated operation by the power failure power supply device, detection means for detecting the output current of the system supplied to the load during the parallel operation, and output of the voltage compensation device for the current detected by the detection means And a current control means for controlling the current to be 1 time or less.

According to the present invention, during the normal operation, the uninterruptible power supply device of the constant inverter feeding system and the voltage compensator are operated in parallel, and the output of the voltage compensator is less than 1 time the output current of the system. By performing the control so that the loss is reduced in the converter device and the inverter device in the continuous inverter power feeding type uninterruptible power supply device, the efficiency of load power feeding can be improved.

Further, the continuous inverter power supply type uninterruptible power supply unit can be switched to the independent operation so that more reliable operation can be performed.

According to a sixth aspect of the present invention, in the uninterruptible power supply system according to the fifth aspect, the current control by the current control means is stopped when a failure occurs in the continuous inverter power feeding type uninterruptible power supply device. In addition, it has a switching means for switching to the independent operation of the voltage compensation device.

According to the present invention, during normal operation, loss is reduced by parallel operation of the continuous inverter power supply type uninterruptible power supply and the voltage compensator, and when a failure occurs in this uninterruptible power supply, By operating the voltage compensator independently after stopping the current control, it is possible to realize a system with low cost and low loss as a whole.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

[First Embodiment] FIG. 1 is a circuit diagram showing a configuration of an uninterruptible power supply system according to a first embodiment. The uninterruptible power supply device 20a is a device that is used regularly, and supplies power to the load during normal operation and during power failure. On the other hand, the uninterruptible power supply 20c is a device used as a backup, and performs load power supply when the uninterruptible power supply 20a fails or when the uninterruptible power supply 20a is inspected.

In the uninterruptible power supply device 20a, during normal operation, the AC power output from the commercial power supply 1 is input to the converter device 11a via the AC input breaker 6a and the AC input filter circuit 3a and converted into DC power. To be done.
This DC power is smoothed by the DC smoothing capacitor 5a and converted into AC power by the inverter device 12a. The electric power converted into alternating current again is the alternating current output filter circuit 4a.
Is output to the non-instantaneous-interruption changeover switch 13a via. The non-instantaneous-interruption changeover switch 13a is a switch for switching between such a power supply path and a bypass path without instantaneous interruption, and normally connects the power supply path to the AC output circuit breaker 9a. The AC output circuit breaker 9a is normally closed and connects the output line of the uninterruptible power supply 20a to the load 14. With such a configuration, the uninterruptible power supply 20a will be referred to as a constant inverter power supply power supply. The storage battery (DC power supply) 2a is used for the converter device 11 during normal operation.
It is designed to be charged by a.

Here, when the power failure of the commercial power supply 1 occurs, the DC power from the storage battery 2a is supplied to the DC input breaker 7a.
And to the inverter device 12a via the DC smoothing capacitor 5a. The DC power is the inverter device 12
It is converted into AC power at a and supplied to the load 14 via the hitless changeover switch 13a and the AC output circuit breaker 9a.

When a failure occurs in the uninterruptible power supply circuit 20a, it is automatically switched to the bypass route by the non-instantaneous interruption changeover switch 13a based on the failure detection signal. An uninterruptible power supply 20c is connected to this bypass path via a bypass input circuit breaker 10, and the power supply is switched to load by the uninterruptible power supply 20c so that the uninterruptible state can be maintained.

In the uninterruptible power supply 20c, the AC power supplied from the commercial power supply 1 is output as it is to the bypass input breaker 10 via the bypass input breaker 8c and the non-instantaneous interruption changeover switch 13c during its operation. It has become so. With such a configuration, the uninterruptible power supply 20b will be referred to as a constant commercial power supply system. The AC circuit breaker 9 provided at the output stage of the uninterruptible power supply 20a
When a is closed, the AC circuit breaker 9b provided at the output stage of the uninterruptible power supply 20c is open, and the AC power from the uninterruptible power supply 20c is passed through the bypass path of the uninterruptible power supply 20a. It is supplied to the load 14.
In addition, the storage battery (DC power supply) 2c is the uninterruptible power supply 20
During the operation of c, the charger 15 charges the battery using an AC power source.

Here, when the commercial power supply 1 fails during power supply to the load by the uninterruptible power supply 20c, the DC power from the storage battery 2c is passed through the DC input breaker 7c and the DC smoothing capacitor 5c to the inverter device. 12c is supplied. The DC power is converted into AC power by the inverter device 12c, and this AC power is supplied to the load 14 through the bypass path of the uninterruptible power supply 20a.

As described above, since the uninterruptible power supply 20a has two types of converters, the converter 11a and the inverter 12a, the cost is generally high, whereas the uninterruptible power supply 20c is the inverter. Although it has 12b, the commercial power supply 1 is used as it is as the main electric power during operation, so that the converter device is not necessary and it can be realized at low cost.

When inspecting the uninterruptible power supply 20a, the AC output breaker 9a is opened, the AC output breaker 9b is closed, and the uninterruptible power supply 20c and the uninterruptible power supply 20a are connected. The bypass input circuit breaker 10 is opened. As a result, the uninterruptible power supply 20a is completely disconnected from the load power feeding path, and safe inspection is possible while maintaining uninterruption.

Therefore, according to the present embodiment, as the backup uninterruptible power supply device, the continuous commercial power supply system device that outputs the commercial power supply as it is during the normal operation is used. The converter device of the device can be eliminated, and the uninterruptible power supply system can be realized at low cost.

Further, according to the present embodiment, the bypass input breaker 10 for opening and closing the connection between the output stage of the uninterruptible power supply 20c and the input stage of the uninterruptible power supply 20a, and the uninterruptible power supply 20a are not provided. AC output circuit breakers 9a, 9b for connecting one of the output lines of the power failure power supply 20c to the load 14
By providing the and, when the uninterruptible power supply 20a is inspected, it is possible to completely disconnect the uninterruptible power supply 20a from the load power supply path, and it is possible to perform a safe inspection while maintaining uninterruption. can do.

The bypass input breakers 8a and 10 of the uninterruptible power supply 20a may be double throw type contactors. Further, double-throw type contactors can be similarly used for the AC output circuit breakers 9a and 9b.

[Second Embodiment] FIG. 2 is a circuit diagram showing a configuration of an uninterruptible power supply system according to a second embodiment. Although the basic configuration is the same as that shown in FIG. 1, the storage battery 2a of the uninterruptible power supply 20a is shared with the uninterruptible power supply 20c, and the storage battery 2c and the charger 15 are connected from the uninterruptible power supply 20c. Has been deleted. In addition, the same components as those in FIG. 1 are designated by the same reference numerals.

In the configuration of FIG. 1, the storage battery 2c is charged by the charger 15. However, the DC power stored in the storage battery 2c is used when the commercial power supply 1 has a power failure, which is extremely high. Since it is a short period of time, if the battery is sufficiently charged in advance, the battery can be operated even if the charging is stopped during the period in which the load power is supplied by the uninterruptible power supply 20c.

Therefore, in the present embodiment, the storage battery 2a of the uninterruptible power supply 20a is also used in the uninterruptible power supply 20c on the assumption that the storage battery is not charged when the load is fed by the uninterruptible power supply 20c. I'm going to share it.

That is, when the uninterruptible power supply unit 20a fails and is switched to the uninterruptible power supply unit 20c, the storage battery 2a is already sufficiently charged by the uninterruptible power supply unit 20a. In the device 20c, the storage battery 2a is used as it is without further charging.

Therefore, according to the present embodiment, the storage battery 2a is shared by the uninterruptible power supply units 20a and 20c, so that the uninterruptible power supply unit 20c can be connected to the charger 15.
Can be eliminated and an uninterruptible power supply system can be realized at low cost.

[Third Embodiment] FIG. 3 is a circuit diagram showing a configuration of an uninterruptible power supply system according to a third embodiment. Although the basic configuration is the same as that shown in FIG. 1, the uninterruptible power supply 20c is replaced with a voltage compensator 20d. In addition, the same components as those in FIG. 1 are designated by the same reference numerals.

The voltage compensating device 20d has a rectifier 16, a DC smoothing capacitor 5c, an inverter device 12d, and a voltage compensating transformer 17, and has only the voltage compensating function.

In the voltage compensator, an inverter device having a capacity corresponding to the compensation width may be prepared. For example, when compensating up to a voltage drop of 20% of the rated voltage, the capacity of 20% of the rated capacity is used. Inverter device is enough.

Therefore, according to the present embodiment, by adopting the voltage compensator 20d in place of the uninterruptible power supply 20c, the inverter device can be downsized, and the uninterruptible operation can be performed at low cost. A power supply system can be realized.

[Fourth Embodiment] FIG. 4 is a circuit diagram showing a structure of an uninterruptible power supply system according to a fourth embodiment. Although the basic configuration is the same as that shown in FIG. 3, a current detection circuit 21 is provided at the output stage of the AC output circuit breakers 9a and 9b to detect the output current of the system supplied to the load 14 and The inverter device 12d of the voltage compensator 20d based on the output current detected by the control circuit 22.
Is to control the output current of. Other,
The same parts as those in FIG. 3 are designated by the same reference numerals.

During normal operation, the AC output circuit breakers 9a, 9
Both of b are closed to allow the uninterruptible power supply 20a and the voltage compensator 20d to operate in parallel, and the voltage compensator 20d
Is controlled by the current control circuit 22 so that the output becomes 1 times or less than the output current of the system detected by the current detector 21. As a result, a part or all of the output current of the system can be supplied by the voltage compensation device 20d, and the converter device 1 in the uninterruptible power supply device 20a can be supplied.
The loss in 1a and the inverter device 12a is reduced.

For more reliable operation, the load is fed by the uninterruptible power supply unit 20a of the continuous inverter feeding system alone.

When a failure occurs in the uninterruptible power supply 20a, the current control by the current control circuit 22 is stopped based on the failure detection signal, and then the voltage compensator 20d is switched to the independent operation.

When inspecting the uninterruptible power supply 20a, the AC output breaker 9a is closed, 9b is opened, the bypass input breaker 10 is closed, and the AC power output from the voltage compensator 20d is supplied to the uninterruptible power supply. The load 14 is supplied via the bypass of the device 20a.

Therefore, according to this embodiment, during the normal operation, the uninterruptible power supply 20a and the voltage compensator 20d are operated in parallel and the voltage compensator 2 is used.
By controlling the output current of 0d to be less than or equal to 1 time the output current of the system detected by the current detector 21, the loss in the converter device and the inverter device in the uninterruptible power supply device 20a is reduced. Therefore, the efficiency of power supply to the load can be improved.

Further, according to the present embodiment, the continuous inverter power supply type uninterruptible power supply system 20a can be switched to the independent operation so that more reliable operation can be performed.

Further, according to the present embodiment, during normal operation, the uninterruptible power supply 20a and the voltage compensator 20d.
The loss in the inverter device and the converter device is reduced by the parallel operation by the above, and the operation is switched to the independent operation by the voltage compensator during the failure or inspection of the uninterruptible power supply 20a, so that the overall cost is low and the loss is low. It is possible to realize various systems.

[0050]

As described above, according to the uninterruptible power supply system of the first aspect, the continuous uninterruptible power supply system that outputs the commercial power supply as it is during normal operation is used as the uninterruptible power supply device for backup. By doing so, the converter device of the standby uninterruptible power supply can be eliminated, and the uninterruptible power supply system can be realized at low cost.

According to the uninterruptible power supply system of claim 2, when inspecting the uninterruptible power supply device of the constant inverter power supply system, the input stage of the uninterruptible power supply device of the constant inverter power supply system and the uninterruptible power supply system of the continuous commercial power supply system are used. Open the connection with the output stage of the uninterruptible power supply, connect the output line of the uninterruptible power supply of the constant commercial power supply system to the load, and connect the output line of the uninterruptible power supply of the continuous inverter supply system to the load By allowing the power supply to be opened, the uninterruptible power supply device of the constant inverter power supply system can be completely disconnected from the load power supply path, and safe inspection can be performed while maintaining the uninterruptible power supply.

According to the uninterruptible power supply system of claim 3, since the storage battery is shared by the uninterruptible power supply device of the constant inverter power feeding system and the uninterruptible power supply device of the constant commercial power feeding system, the continuous commercial power feeding is performed. It is possible to eliminate the need for a charger from the system uninterruptible power supply, and to realize an uninterruptible power supply system at low cost.

According to the uninterruptible power supply system of claim 4, the voltage compensation device is used instead of the uninterruptible power supply device of the constant commercial power feeding system, so that the inverter device can be downsized and the cost can be further reduced. It is possible to realize an uninterruptible power supply system.

According to the uninterruptible power supply system of claim 5, during normal operation, the continuous inverter power supply type uninterruptible power supply and the voltage compensator are operated in parallel, and the output of the voltage compensator is set to the output current of the system. By controlling so as to be less than or equal to 1, the loss in the converter device and the inverter device in the continuous inverter power supply uninterruptible power supply device is reduced, and the efficiency of load power supply can be improved. .

Further, it is possible to switch to the independent operation by the uninterruptible power supply system of the constant inverter power feeding system, so that more reliable operation can be performed.

According to the uninterruptible power supply system of claim 6, the loss is reduced by the parallel operation of the continuous inverter power supply type uninterruptible power supply and the voltage compensator during the normal operation, and the uninterruptible power supply fails. When it occurs, the current control is stopped and then the islanding operation is performed by the voltage compensator, so that a system with low cost and low loss can be realized as a whole.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a configuration of an uninterruptible power supply system according to a first embodiment.

FIG. 2 is a circuit diagram showing a configuration of an uninterruptible power supply system according to a second embodiment.

FIG. 3 is a circuit diagram showing a configuration of an uninterruptible power supply system according to a third embodiment.

FIG. 4 is a circuit diagram showing a configuration of an uninterruptible power supply system according to a fourth embodiment.

FIG. 5 is a circuit diagram showing a configuration of a conventional uninterruptible power supply system.

[Explanation of symbols]

1 Commercial power supply 2a, 2b, 2c storage battery 3a, 3b AC input filter circuit 4a, 4b, 4c AC output filter circuit 5a, 5b, 5c DC smoothing capacitors 6a, 6b AC input circuit breaker 7a, 7b, 7c DC input circuit breaker 8a, 8b, 8c Bypass input circuit breaker 9a, 9b AC output circuit breaker 10 Bypass input circuit breaker 11a, 11b converter device 12a, 12b, 12c Inverter device 13a, 13b, 13c Instantaneous disconnection changeover switch 14 load 15 charger 16 Rectifier 17 Voltage Compensation Transformer 20a, 20b, 20c uninterruptible power supply 20d voltage compensator 21 Current detection circuit 22 Current control circuit

Claims (6)

[Claims] 1. An uninterruptible power supply device of a constant inverter power supply system for supplying alternating-current power to a load during normal operation, an uninterruptible power supply device of a continuous commercial power supply system for backup, and an uninterruptible power supply of a constant inverter power supply system. An uninterruptible power supply system comprising: switching means for switching to an uninterruptible power supply of a constant commercial power supply system when a failure occurs in the device. 2. An open / close means for opening and closing a connection between an input stage of the constant inverter power supply type uninterruptible power supply and an output stage of the constant commercial power supply type uninterruptible power supply, and these two types of uninterruptible power supply. 2. The uninterruptible power supply system according to claim 1, further comprising: a connecting means for connecting one of the output lines to a load. 3. A storage battery is shared between the uninterruptible power supply device of the constant inverter power supply system and the uninterruptible power supply device of the constant commercial power supply system, and a charger for the storage battery is not required for the uninterruptible power supply device of the constant commercial power supply system. The uninterruptible power supply system according to claim 1 or 2, characterized in that. 4. The uninterruptible power supply system according to claim 1, wherein a voltage compensation device is used in place of the uninterruptible power supply device of the constant commercial power supply system. 5. A switching unit that switches between parallel operation by the constant inverter power supply type uninterruptible power supply device and the voltage compensator and independent operation by the constant inverter power supply type uninterruptible power supply device, and during the parallel operation, A detection means for detecting the output current of the system supplied to the load; and a current control means for controlling the output current of the voltage compensator to be less than or equal to 1 times the current detected by the detection means. The uninterruptible power supply system according to claim 4. 6. When the uninterruptible power supply device of the constant inverter power feeding system has a failure, it has a switching means for stopping the current control by the current control means and then switching to the independent operation of the voltage compensation device. The uninterruptible power supply system according to claim 5.