JPH0833230A - Uninterruptible power supply - Google Patents

Abstract

PURPOSE:To control the temperature rise of an input transformer, having capacity selected while paying no attention to the charging capacity of a battery, within an allowable range under any conditions by varying the charging current limit value for a charging current setter based on a temperature detection signal. CONSTITUTION:Switching is made from a commercial power supply to a battery 8 upon power interruption. When the power supply is reset, the commercial power supply 1 feeds the charging power to the battery 8 in addition to the power for a load, and the rated output capacity of an input transformer 2 is exceeded if the rated capacity is fed to the load side. In other words, the load capacity is added to the charging capacity of battery to cause a current flow larger than the rated value. Consequently, the temperature of the winding increases and when a temperature detector 21 detects a temperature higher than a predetermined level, a set charging current correction unit 23 corrects the charging current limit value in the direction for lowering the maximum charging current IBMAX required by the battery. Since the charging current of the battery 8 lowers, the output capacity of the input transformer 2 decreases to stop temperature rise of the winding and keeps the temperature rise within a prescribed level.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a constant voltage constant frequency output uninterruptible power supply device having a charging function for a storage battery, and more particularly to an uninterruptible power supply device having improved control of a charger.

[0002]

2. Description of the Related Art The configuration of one uninterruptible power supply is shown in FIG.
There was something shown in. In FIG. 5, 1 is a commercial power supply, 2 is an input transformer that converts the input power supply voltage, and performs insulation.
Is a converter for converting AC power into DC power, 4 is an inverter for converting the converted DC power into AC power again,
5 is an AC filter circuit, 6 is an AC output switch, 7 is a load, 8 is a storage battery that supplies power to the load 7 during a power failure of the commercial power supply, 9 is an inverter control circuit that controls the AC output to a constant voltage and constant frequency, 10 Is a converter gate control circuit.
Reference numeral 11 is a converter voltage controller, which is a command value V0 of the DC voltage setter 12 and a DC voltage detection signal Vd of the DC voltage detector 13.
The voltage of the storage battery 8 is controlled to a constant value by making a contact with. Reference numeral 14 is a charging current controller so that the charging current detection signal IB detected by the charging current detector 15 flowing from the DC circuit to the storage battery 8 does not exceed the charging current limit value IBMAX preset by the charging current setting device 16. Interrupts the converter voltage control.

In such an uninterruptible power supply device, the capacity of the input transformer 2 is usually determined by the rated output capacity of the device, and is determined by the charge current limit value IBMAX of the discharged storage battery 8 after the commercial power supply 1 fails. It is designed with a value that includes charging capacity.

[0004]

The capacity of the input transformer 2 of the uninterruptible power supply device designed as described above is such that the storage battery 8 is charged for a long time during charging as the reliability of the commercial power supply 1 is improved. The probability that the current of the current limit will flow is extremely reduced, and the capacity during normal operation has a margin. On the other hand, there is a strong demand for downsizing and cost reduction of the uninterruptible power supply, and it is expected that the capacity of the input transformer 2 will be reduced.

The present invention has been made to solve the above problems, and provides an uninterruptible power supply capable of reducing the capacity of the input transformer 2 to the minimum capacity required during normal operation. The purpose is to do.

[0006]

To achieve this object, the present invention provides a converter for converting an alternating current supplied from an alternating current power source through an input transformer into a direct current. An inverter that converts the direct current into an alternating current to supply alternating current power to the load, a storage battery that supplies direct current to the inverter during a power failure of the alternating current power supply, a charging current limit value and a charging current set by a charging current setting device. In the uninterruptible power supply device comprising a charging means for charging the storage battery via the converter according to a deviation signal of the detected value, and a temperature detecting means for detecting the temperature of the winding of the input transformer, the charging current The setting device is characterized in that the charging current limit value of the charging current setting device is changed by the temperature detection signal of the temperature detecting means.

Further, the invention of claim 2 is a converter for converting an alternating current supplied from an alternating current power source through an input transformer into a direct current, and a converter for converting the converted direct current into an alternating current to supply alternating current power to a load. An inverter, a storage battery that supplies direct current to the inverter during a power failure of the AC power supply, and the storage battery via the converter according to a deviation signal between a charging current limit value and a charging current detection value set by a charging current setting device. In the uninterruptible power supply device having a charging means for charging, and a direct current input to the inverter, or a means for detecting a direct current power, the charging current setting device, the direct current or direct current power detected by the means. The charging current limit value of the charging current setting device is changed by.

Further, according to the invention of claim 3, a converter for converting an alternating current supplied from an alternating current power source through an input transformer into a direct current, and a converter for converting the converted direct current into an alternating current to supply alternating current power to a load. Inverter, a storage battery that supplies direct current to the inverter during a power failure of the AC power supply, the storage battery via the converter according to the deviation signal of the charging current limit value and the charging current detection value set by the charging current setting device In the uninterruptible power supply device including a charging unit for charging the charging unit and a unit for detecting the temperature of the semiconductor element or the cooling fin that constitutes the converter, the charging current limit value of the charging current setting unit is determined by the temperature detection signal of the temperature detection unit. It is characterized by changing.

Further, the invention of claim 4 is a converter for converting an alternating current supplied from an alternating current power source through an input transformer into a direct current, and a converter for converting the converted direct current into an alternating current to supply alternating current power to a load. An inverter for supplying, a storage battery for supplying direct current to the inverter at the time of power failure of the AC power supply, and the converter via the converter according to a deviation signal of a charging current limit value and a charging current detection value set by a charging current setting device. In the uninterruptible power supply device having a charging means for charging the storage battery and a means for detecting active power or active current supplied to the load, the charging current of the charging current setting device by the active power or active current detected by the means. The feature is that the limit value is variable.

[0010]

According to the invention as set forth in claim 1, an overload condition of the input transformer is detected by the temperature of the input transformer, and the detected signal indicates that the temperature of the input transformer is equal to or higher than a predetermined value. Since the setting is changed so as to decrease the limit value of the charging current of the storage battery, the input transformer selected with a capacity that does not consider the charging capacity of the storage battery controls the temperature rise below the allowable value under any conditions. It is possible to reduce the capacity, reduce the size, and reduce the cost without deteriorating the life of the transformer.

According to the second aspect of the present invention, when the overload state of the input transformer is detected by the DC current or DC power input to the inverter and the overload state is detected by the means. In addition, since the setting is changed so as to decrease the limit value of the charging current of the storage battery, like the invention of claim 1, without deteriorating the life of the input transformer,
It is possible to reduce the capacity, reduce the size, and reduce the cost.

Further, according to the invention of claim 3, the limit value of the charging current of the storage battery is lowered by the signal indicating that the load state of the input transformer has exceeded the predetermined value. Since I changed the setting to the direction to make it,
Similarly to the invention of claim 1, the capacity can be reduced, the size can be reduced, and the cost can be reduced without deteriorating the life of the input transformer.

Further, according to the invention described in claim 4,
Since the overload state of the input transformer is detected by the means for detecting active power or active current output from the inverter, the detection signal is used to change the setting so as to lower the limit value of the charging current of the storage battery. Similar to the invention of claim 1,
It is possible to reduce the capacity, reduce the size, and reduce the cost without deteriorating the life of the input transformer.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIG. In FIG. 1, the components denoted by the same reference numerals as those in FIG. 5 have the same functions as those in FIG. 5, and the description thereof will be omitted.

In FIG. 1, 21 is a temperature detector for detecting the temperature TDET of the winding of the input transformer, 22 is a charging current setting device for setting a charging current limit value determined from the capacity of the storage battery, and 23 is an input transformer. The charging current setting compensator corrects the charging current limit value set by the charging current setting device 22 in a direction to decrease when the temperature TDET of the second winding exceeds a predetermined value.

FIG. 2 is a diagram showing the relationship between the winding temperature TDET and the charging current limit value IBO. Hereinafter, the present invention will be described assuming that the capacity of the input transformer 2 is designed from the capacity required from the load side (the charging capacity of the storage battery is not expected when the rated capacity is acquired from the load side).

When the commercial power supply 1 is healthy and the storage battery 8 is sufficiently charged, the charging current to the storage battery 8 is almost zero, and the power supply capacity supplied via the input transformer 2 is almost supplied to the load. It depends on the power that is used. If a power failure occurs in this state, the commercial power source 1 will be the source of power to the load side.
To the storage battery 8.

When power is supplied from the storage battery 8 during the power failure period, when the commercial power source 1 recovers from the power failure, the commercial power source 1 adds the power supplied to the load and the charging power to the storage battery 8. The output capacity of the hour input transformer 2 exceeds the rating if the rated capacity is supplied to the load side. The design of the transformer 2 is designed so that when the current of the rated load capacity is continuously supplied, it becomes less than or equal to the maximum temperature allowable value according to the class of the applied insulation type. The load capacity and the storage battery charge capacity are added to cause a current exceeding the rating to flow, the temperature of the winding rises, and the temperature of the temperature detector 21 rises to a predetermined value TL
When it exceeds, as shown in FIG. 2, the charging current limit value IBO operates to decrease the output of the charging current setting corrector 23 from the maximum charging current value IBMAX required by the storage battery.
Therefore, since the charging current to the storage battery 8 decreases, the output capacity of the input transformer 2 decreases, the temperature rise of the winding stops, and the temperature is maintained below the specified value. During this time, the storage battery 8 takes longer than initially IBMAX, but continues to be charged at the limit value IBO lower than IBMAX, and eventually the charging is completed.
Return to BMAX.

According to the value of the temperature detection signal TDET, as shown in FIG. 2, when TDET exceeds the temperature TL of the winding capable of supplying the maximum charging current determined by the capacity of the input transformer, the final current limit value is lowered from IBMAX. The current setting compensator 23 sets a preset charging current limit IBO for a predetermined temperature signal.
Can be easily realized by using a storage element such as a ROM that outputs a signal value corresponding to, or by a simple arithmetic circuit.

As described above, the temperature of the input transformer 2 is monitored, and if the temperature exceeds a certain set value, the charging current is controlled so as to reduce the limit value of the charging current of the storage battery 8. Therefore, the capacity of the transformer 2 can be reduced, the body cost can be reduced, and the size can be reduced while being applied within a range in which the life of the input transformer 2 is not deteriorated.

As another embodiment, in FIG.
Although the temperature of the winding is detected, the same charging current control can be performed by detecting the base temperature of the semiconductor element of the converter circuit 3 for converting AC into DC or the cooling fin.

FIG. 3 is a diagram showing an embodiment for detecting a direct current as a method of detecting the amount of electric power supplied to the load side.
In this figure, the same elements as those in FIG. 1 are designated by the same reference numerals. In FIG. 3, reference numeral 26 is a DC current detector, and 27 is a charging current for correcting the charging current limit value set by the charging current setting unit 22 when the detected current IDET of the DC current detector exceeds a predetermined value. It is a setting corrector.

FIG. 4 is a diagram showing the relationship between the DC current detection signal IDET and the charging current limit value IBO. In FIG. 3, when the load factor increases and the DC current detection signal IDET exceeds the DC current IL that can be supplied by the maximum charging current determined by the input transformer 2, the output of the charging current setting unit 23 decreases as shown in FIG. The charge current limit value IBO operates in the direction. Therefore, even if the storage battery 8 is charged in this state, the capacity supplied from the AC input side, that is, the output capacity of the input transformer 2 is maintained below a predetermined value. That is, storage battery 8
If the capacity of the input transformer 2 is not exceeded from the sum of the capacity supplied to the capacitor and the load capacity detected as a direct current, the capacity of the input transformer can be reduced as compared with the conventional case. Although the DC current is detected in FIG. 3, the same charging current control can of course be performed by using the DC power, the active power on the output side, and the power amount such as the active current.

[0024]

As described above, according to the inventions of claims 1 to 4, when the overload state of the input transformer is detected, the limit value of the charging current of the storage battery is lowered. Since it has a function to set the capacity of the input transformer, it is possible to operate the input transformer whose capacity is selected without considering the charging current of the storage battery under any condition within the allowable value. It is possible to reduce the size, downsize the device, and reduce the cost.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of an uninterruptible power supply device of the present invention.

FIG. 2 is a characteristic diagram for explaining the operation of the charging current limit value of the present invention.

FIG. 3 is a block diagram showing another embodiment of the uninterruptible power supply device of the present invention.

FIG. 4 is a characteristic diagram for explaining the operation of another charging current limit value of the present invention.

FIG. 5 is a block diagram showing a conventional uninterruptible power supply device.

[Explanation of symbols]

1 ... Commercial power supply 2 ... Input transformer 3 ... Converter 4 ... Inverter 5 ... AC filter circuit 6 ... AC output switch 7 ... Load 8 ... Storage battery 9 ... Inverter control circuit 10 ... Converter control circuit 11 ... Converter voltage control circuit 12 ... DC voltage setter 13 ... DC voltage detector 14 ... AC current limiter 15 ... Charging current detector 21 ... Temperature detector 22 ... First charging current setter 23 ... Charging current setting corrector 26 ... DC current detector 27 ... Charge current setting compensator V0 ... DC voltage command value Vd ... DC voltage detection signal IB ... Charge current detection signal TDET ... Temperature detection signal IDET ... Current detection signal

Claims (4)

[Claims] 1. A converter for converting alternating current supplied from an alternating current power supply through an input transformer into direct current, an inverter for converting the converted direct current into alternating current and supplying alternating current power to a load, and the alternating current power supply. A storage battery that supplies direct current to the inverter during a power failure, and a charging unit that charges the storage battery via the converter according to a deviation signal of a charging current limit value and a charging current detection value set by a charging current setting device, In an uninterruptible power supply including a temperature detecting unit that detects a temperature of a winding of the input transformer, a function of changing a charging current limit value of the charging current setting unit according to a temperature detection signal of the temperature detecting unit. An uninterruptible power supply characterized by the above. 2. A converter for converting alternating current supplied from an alternating current power supply through an input transformer into direct current, an inverter for converting the converted direct current into alternating current and supplying alternating current power to a load, and the alternating current power supply. A storage battery that supplies direct current to the inverter during a power failure, and a charging unit that charges the storage battery via the converter according to a deviation signal of a charging current limit value and a charging current detection value set by a charging current setting device, In an uninterruptible power supply device having means for detecting a direct current or direct current power input to the inverter, the charging current limit value of the charging current setting device is changed by the direct current or direct current power signal detected by the means. An uninterruptible power supply characterized by having the function of 3. A converter for converting alternating current supplied from an alternating current power supply through an input transformer into direct current, an inverter for converting the converted direct current into alternating current and supplying alternating current power to a load, and the alternating current power supply. A storage battery that supplies direct current to the inverter during a power outage, charging means for charging the storage battery via the converter according to a deviation signal between a charging current limit value and a charging current detection value set by a charging current setting device, and In an uninterruptible power supply device having means for detecting the temperature of an element or a cooling fin that constitutes a converter, the charging current setting device, the charging current limit value of the charging current setting device by the temperature detection signal of the temperature detection means. An uninterruptible power supply characterized by having a variable function. 4. A converter for converting alternating current supplied from an alternating current power supply through an input transformer into direct current, an inverter for converting the converted direct current into alternating current and supplying alternating current power to a load, and the alternating current power supply. A storage battery that supplies direct current to the inverter during a power failure, and a charging unit that charges the storage battery via the converter according to a deviation signal of a charging current limit value and a charging current detection value set by a charging current setting device, In an uninterruptible power supply having a means for detecting active power or active current supplied to the load, a function of varying the charging current limit value of the charging current setting device by the active power or active current signal detected by the means. An uninterruptible power supply characterized by comprising: