JPH04322136A - Power supply - Google Patents

Abstract

PURPOSE:To provide an uninterruptible power supply for computor system, for example, wherein an inverter unit incorporating a battery operates immediately upon temporary interruption of commercial power supply. CONSTITUTION:A first comparator 16 compares a voltage (b) obtained by full- wave rectifying the secondary voltage of an insulating transformer 12 connected with a commercial power supply through a first diode bridge circuit 13 with an output voltage (c) from a second diode bridge circuit 14 obtained by rectifying a reference sine wave voltage fed from a reference sine wave generator 15. A second comparator compares the output (d) from the first comparator with a predetermined DC reference value to produce a power interruption detection output (e) which is then applied on a monostable multivibrator 18 to produce an 'H' level voltage (f) at the time of power interruption. The voltage (f) is fed to a power interruption switching unit 1 which switches the power supply to an inverter connected with a battery thus feeding a load continuously with AC power even upon power interruption.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply device having a power failure detection circuit used in an uninterruptible power supply device of a commercial power source.

0002

BACKGROUND OF THE INVENTION In recent years, there has been a growing demand for uninterruptible power supplies for computer equipment that utilize inverter units with built-in storage batteries immediately in the event of a temporary power outage in the commercial power supply.

The configuration of a conventional power supply device having a power failure detection circuit will be described below with reference to FIGS. 3 and 4.

As shown in the figure, the input commercial power supply voltage h is
The voltage waveform, which is provided on the input side of the power failure switching device 1 and divided into appropriate voltages by resistors 2 and 3, is applied to a diode bridge 4 that performs full-wave rectification. The output waveform of the diode bridge 4 is i in FIG. 4, and the current flowing through the light emitting diode inside the photocoupler 7 due to the diode 5 and Zener diode 6 is j. Therefore, the transistor 8 is switched by the phototransistor of the photocoupler 7, and a pulse having a frequency twice the commercial frequency, such as k, is outputted to the collector, and this pulse is inputted to the mono-multivibrator 9.

The mono-multivibrator 9 is triggered at the rising edge of a pulse, and the pulse width is determined by a time constant determined by a capacitor 10 and a resistor 11. Here, the input pulse k has a frequency twice the power supply frequency, so
For example, if the commercial power supply is 60 Hz, the pulse repetition frequency is 120 Hz, and a pulse rises every 8.3 ms. Therefore, if the mono multivibrator's pulse width is set to 10 ms, the output of the mono multivibrator will be "H" or " It will remain at "L". In other words,
While the transistor 8 is repeatedly turned on and off, the output voltage l of the mono multivibrator 9 maintains "H",
Indicates normality.

However, if a power outage occurs in the input commercial power supply and the pulse does not rise, the transistor 8 stops repeatedly turning on and off, and the output of the mono multivibrator 9 changes from "H" to "L" or from "L" to "L". Since it becomes "H", a power outage state can be detected at that point. When a power outage is detected, the built-in inverter is activated from the storage battery built into the switching device 1 during a power outage, and power can be continued to be supplied to the load.

[0007]

[Problem to be Solved by the Invention] However, in the conventional configuration described above, it is difficult to detect a power outage in case of a momentary power outage in which a power outage occurs after a pulse rises but returns before the next pulse rises. I can't.

Furthermore, in the above configuration, the mono multivibrator 9 determines whether there is a power outage or not depending on whether or not the input signal is repeatedly inverted, and the pulse width set in the mono multivibrator 9 It also needs to be a certain length. Moreover, even if a power outage occurs immediately after the pulse starts rising, a power outage detection output cannot be obtained until the time equal to the pulse width set in the mono-multivibrator 9 has elapsed. For example, the pulse width is set to 10 ms. Therefore, there was a problem in that a power failure detection output could not be obtained for a maximum of 10 ms.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems, and aims to provide a power supply device having a power outage detection circuit using a waveform comparison method that can detect instantaneous power outages. It is said that

0010

[Means for Solving the Problems] In order to achieve the above object, the power supply device of the present invention provides a
an isolation transformer for obtaining the next output level voltage; a first diode bridge circuit for full-wave rectification of the output of the transformer; and a first diode bridge circuit for full-wave rectification of the output of the transformer; a reference sine wave generator that serves as a reference for the first comparator, and a second comparator that full-wave rectifies the reference sine wave to generate a pulsating flow.
A diode bridge circuit is provided, and the output voltages of the first and second diode bridge circuits are compared by a first comparator, and the output of the first comparator is compared with a reference value to detect a power outage. The output of the second comparator is added to the mono-multivibrator, and the "H" level voltage at the time of a power outage is used to start an inverter using a storage battery built into the switching device during a power outage. It is constructed so that it can continue to supply alternating current voltage without momentary power outage.

[0011]

[Operation] With the above configuration, the commercial primary power supply voltage is input to the first comparator as an appropriate secondary output level, and the first comparator composed of a differential amplifier generates a reference sine wave. changes in the commercial power supply waveform are detected by comparing it with the reference sine wave created by the device.

The error voltage of the first comparator is compared with a preset threshold in a second comparator using a hysteresis comparator, and if it exceeds the threshold, a power outage detection signal is output and the power outage is instantaneously interrupted. This can be used as a power supply device that outputs a detection signal.

[0013]

Embodiment An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

As shown in the figure, an isolation transformer 12 is provided on the input side of the switching device 1 during a power outage to adjust the commercial primary power supply voltage to an appropriate secondary output level. The secondary output of the isolation transformer 12 is full-wave rectified by the first diode bridge circuit 13 to form a pulsating current. Next, the reference sine wave generated by the reference sine wave generator 15 is transmitted to the second diode bridge circuit 1.
4, full-wave rectification is performed to create a pulsating flow. The outputs of the first and second diode bridge circuits 13 and 14 are compared by a first comparator 16, and a hysteresis comparator compares the power failure detection error output from the comparator 16 with a preset threshold voltage. Two comparators 17 are provided. In addition, the second
Inputting the output of the comparator 17 to the mono multivibrator 18 is the same as in the conventional example. Further, the output voltage from the mono-multivibrator 18 is applied as a control signal to the switching device 1 during a power outage, as in the conventional example. The power outage switching device 1 is configured to include a storage battery, a charger, an inverter circuit, and a switch for switching the output from the commercial power supply line and the inverter circuit when a power outage occurs.

FIGS. 1 and 2 show the operation of the uninterruptible power supply equipped with the power failure detection circuit configured as described above.
Explain using.

As shown in the figure, the secondary output waveform a of the isolation transformer 12 obtains an output waveform b from the first diode bridge circuit 13 at an appropriate level. Here, the output waveform a,
b shows a case where a power outage occurs. Further, the reference sine wave generated by the reference sine wave generator 15 is full-wave rectified by the second diode bridge circuit 14 to obtain an output waveform c. The output waveform b of the first diode bridge circuit obtained from the above-mentioned commercial power supply waveform and the output waveform c obtained from the reference sine wave are applied to the input side of the first comparator 16 in opposite phases. , in the steady state, the output of the first comparator 16 is G
Offset adjustment is performed so that it becomes an ND level. That is, when a momentary power outage or power outage occurs in the commercial power supply, a dropout occurs in the commercial power supply waveform (voltage waveform b) that is one input of the operational amplifier of the first comparator 16, and the first comparator 1
6 amplifies the difference between the commercial power supply and the reference sine waveform to obtain an output waveform d. The output d is applied to the positive input terminal of the second comparator 17, and compared with a preset reference DC voltage applied to the negative input terminal, and if it exceeds the reference value, the second comparator 17 The output waveform e of is inverted from "L" to "H". In other words, during a power outage, after once reaching the “H” level, the G level near the zero cross point of the sine wave voltage
However, if the output of the second comparator 17 is input to the mono multivibrator 18, which triggers at the rising edge of the pulse and outputs a pulse with a pulse width slightly longer than twice the period of the power supply frequency, As shown in the output waveform f, it can be maintained at the "H" level during a power outage.

As mentioned above, when it is detected that a power outage has occurred in the commercial power source, the power outage switching device 1 switches to the built-in storage battery that was previously charged with the charger, and at the same time starts the inverter to supply power to the load. It is possible to provide an excellent power supply device that can provide uninterruptible power supply that can continue to be supplied.

[0018]

[Effects of the Invention] As is clear from the above embodiments, according to the present invention, when a momentary power outage occurs in the commercial power supply, the power outage is immediately detected and the storage battery that was previously charged with the charger is switched to. At the same time, it is possible to provide an excellent power supply device that can realize uninterrupted power supply by starting the inverter and continuing to supply power to the load.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a power supply device having a power failure detection circuit according to an embodiment of the present invention.

[Fig. 2] Operation waveform diagram in one embodiment of the present invention

[Figure 3]
Block diagram of a power supply device with a conventional power failure detection circuit

[Figure 4] Operation waveform diagram of conventional example

[Explanation of symbols]

1 Power failure switching device 12 Isolation transformer 13 First diode bridge circuit 14 Second diode bridge circuit 15 Reference sine wave generator 16 First comparator 17 Second comparator

Claims (1)

[Claims] 1. An isolation transformer for insulating a commercial primary power supply voltage to obtain an appropriate secondary output level; a first diode bridge circuit for full-wave rectification of the output of the isolation transformer to produce a pulsating current; A first comparator into which the output of the diode bridge circuit is input to one terminal of an operational amplifier, a reference sine wave generator that serves as a reference for the first comparator, and a pulse generator that performs full-wave rectification of the reference sine wave. a second diode bridge circuit whose output is input to the other terminal of the first comparator; and a second comparator which detects a power outage based on the output of the first comparator. A power supply device equipped with a switching device during a power outage to perform instantaneous operation.