JP3003238B2 - Output voltage controller for uninterruptible power supply - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an output voltage control device for an uninterruptible power supply (hereinafter referred to as UPS).

[0002]

2. Description of the Related Art A UPS using a CVCF (constant voltage / constant frequency) by an inverter is widely used as a power supply device for supplying a stable power at a constant voltage and a constant frequency to a load such as a computer which is constantly operating. Have been.
In the power supply system including the UPS, a power supply system is multiplexed for a load in which a power failure is not allowed. For example, a computer of a plant or bank that is continuously operated requires 365 days 2
Four hours of operation is required.

FIG. 3 schematically shows the configuration of the UPS system. In FIG. 3, reference numerals 31a to 31n denote CVCFs.
The output voltages of these CVCFs 31a to 31n are supplied to the CVCF bus 34 via circuit breakers 32a to 32n. A plurality of loads 35a to 35n are connected to the CVCF bus 34. The loads 35 a to 35 n are configured so that power can be supplied from the bypass power supply 36.

[0004]

In the UPS system shown in FIG. 3, the voltage at the voltage detection point 37 of the CVCF bus 34 is detected in order to control the output voltages of the CVCFs 31a to 31n at a constant level.
31n. However, in recent years, the semiconductor circuit breakers 38a to 38n are connected to the output feeders in order to increase the capacity of the UPS system and to rapidly cut off the loads 35a to 35n connected to the output feeders as shown in FIG. Due to the fact that the CVCFs 31a to 31n are output from the 400V system, the current is reduced, and the transformer 39a is used as the final output.
Means for stepping down to a 200 V load system voltage such as a computer load at 39 to 39 n is taken.

When the semiconductor circuit breakers 38a to 38n and the transformers 39a to 39n are used for the output feeder as described above, a voltage drop occurs due to these. For this reason, FIG.
When the output voltages of the CVCFs 31a to 31n are controlled by the voltage detection points 37 shown in FIG. 2, the voltage detection points D _{21 to} D _2n shown in FIG.
There is a disadvantage that the voltage fluctuation becomes large enough to cause a practical problem.

In FIG. 2, reference numerals 40a to 40n denote C.
Semiconductor switches for contactlessly switching from VCFs 31a to 31n to bypass power supply 36, semiconductor switches 41a to 41n, and semiconductor switches 41a to 41n
This is a switch for switching from the CVCFs 31a to 31n to the bypass power supply 36 after the 40n is turned on.

SUMMARY OF THE INVENTION The present invention has been made in order to eliminate the above-mentioned drawbacks. The present invention controls the output voltage of a UPS comprising a CVCF to compensate for a voltage drop of an output feeder for supplying power to a load, and to reduce a voltage drop between output feeders. A UPS that controls the CVCF so that the voltage variation is reduced and the control voltage is kept within the control value even when the voltage exceeds the upper and lower limit values.
It is an object of the present invention to provide an output voltage control device.

[0008]

According to a first aspect of the present invention, in order to achieve the above object, the outputs of a plurality of uninterruptible power supplies are supplied to a plurality of loads via respective output feeders and each output feeder is provided. In an uninterruptible power supply system in which a semiconductor circuit breaker is interposed, an output terminal voltage detector for detecting an output terminal voltage of each output feeder connecting each semiconductor circuit breaker and each load, and the detector detects the output terminal voltage. An averaging circuit for averaging the output terminal voltage, a deviation detector for obtaining a deviation between the output terminal voltage averaged by the averaging circuit and the reference voltage, and a deviation output of the deviation detector are supplied. And a control command generator for generating a command for controlling the output voltage of the uninterruptible power supply according to the deviation output. In a second aspect of the present invention, an upper / lower limit value setting unit for detecting a rise or fall of the output terminal voltage is provided. The control command is generated so that the output terminal voltage which has been increased or decreased by correcting the output falls within the limit value.

[0009]

The detected voltage of the output terminal voltage detector is averaged by the averaging circuit, compared with the reference voltage, and a command is sent from the control command generator to the uninterruptible power supply so that the deviation becomes zero. . Further, when the voltage drop of a specific output feeder becomes large and the drop exceeds the lower limit value setting unit, the deviation output is corrected so that the output terminal voltage falls within the limit value.

[0010]

An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 1 denotes a voltage averaging circuit. The circuit 1 has output terminal voltage detection points D _{21 to} D ₂₁ shown in FIG.
_A detection voltage is input from an output terminal voltage detector (not shown) that detects the voltage of _2n . Reference numerals 2 and 3 denote resistors.
Upper and lower limit value setting unit to the common connection point 4 ₁ to 4 _n between 3 5 ₁
５5 _n inputs are connected. Upper limit set value and lower limit set value is input to the setting unit 5 ₁ to 5 _n. The output side of the upper and lower limit value setting unit 5 ₁ to 5 _n is connected to the upper and lower limit correction unit 7 through the amplifier 6.

The averaged output of the averaging circuit 1 is supplied to a positive input terminal of a deviation detector 8. Deviation detector 8
Is supplied with a reference voltage from a setting device (not shown). The output of the deviation detector 8 is input to the upper / lower limit correction unit 7. The upper / lower limit correction unit 7 is an upper / lower limit value setting unit 5 ₁
5 the output of the deviation detector 8 when no output from _n is supplied to the control command generating unit 9, working to apply a correction value to the differential output when there is output from either the setting unit 5 ₁ to 5 _n After that, the output is supplied to the control command generator 9.

[0012] In the embodiment of the present invention configured as described above, now, the voltage value of the output voltage detection point D ₂₁ and D ₂₂ are the drops. The averaging circuit 1 averages the input output terminal voltage and supplies the output to the deviation detector 8. The deviation detector 8 compares the output with the reference voltage, and outputs the deviation output via the upper / lower limit correction unit 7 to the control command generation unit 9.
Give to. Control command generating unit 9 uninterruptible power supply controls to the detection point D ₂₁ to D _2n are set to be the same voltage values according to the input deviation value.

[0013] When the lower limit value setting unit 5 ₁ voltage falls of the output terminal voltage detection point D ₂₁ detects this, and the detection output is supplied to the upper and lower limit correction unit 7. On the other hand, since the deviation output from the deviation detection unit 8 is supplied to the upper / lower limit correction unit 7, the correction unit 7 adds a correction value to the deviation output and supplies it to the control command generation unit 9. The control command generator 9 operates as if a correction value has been added to the deviation output, controls the uninterruptible power supply, and slightly increases the output voltage so as to fall within the limit value. When the output terminal detection voltage rises, the operation opposite to the above is performed.

In the above embodiment, the output terminal voltage detection points D _{21 to} D _{21
Although 2n} has been described as an example, the case where the detection point is further downstream may be used.

[0015]

As described above, according to the present invention,
The voltage drop of each output feed can be compensated, and the voltage variation between each output feeder is reduced on average, and even if it exceeds the upper and lower limit of each output feeder, it will be within the limit. There are advantages to being able to.

[Brief description of the drawings]

FIG. 1 is a configuration explanatory view showing one embodiment of the present invention.

FIG. 2 is an explanatory diagram for describing a problem of a conventional example.

FIG. 3 is a configuration explanatory view showing a conventional example.

[Explanation of symbols]

1 ... averaging circuit 5 ₁ to 5 _n ... upper and lower limit value setting section 7 ... upper and lower limit correction part 8 ... deviation detector 9 ... control command generating section

Claims (2)

(57) [Claims] 1. An uninterruptible power supply system in which outputs of a plurality of uninterruptible power supplies are supplied to a plurality of loads via respective output feeders and each of the output feeders is provided with a semiconductor circuit breaker. Output terminal voltage detector that detects the output terminal voltage of each output feeder that connects the detector and each load, an averaging circuit that averages the output terminal voltage detected by this detector, and an averaging circuit that averages the output terminal voltage. A deviation detector for obtaining a deviation between the quantified output terminal voltage and the reference voltage, and a deviation output of the deviation detector is supplied, and a command for controlling an output voltage of the uninterruptible power supply is generated in accordance with the deviation output. An output voltage controller for an uninterruptible power supply, comprising: a control command generator. 2. An upper / lower limit value setting section for detecting a rise or a drop of an output terminal voltage, and an upper / lower limit correction section to which an output of the setting section is supplied is provided. 2. The output voltage control device for an uninterruptible power supply according to claim 1, wherein a correction value is given to the deviation output.