JP2508074B2 - DC uninterruptible power supply - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a DC uninterruptible power supply device in which a switching regulator used as a power source for driving OA equipment or communication equipment is uninterrupted.

2. Description of the Related Art Conventional technology and its problems As switching rectifiers used as driving power sources for OA equipment and communication equipment, those shown in FIG. 3 are known. That is, in FIG. 3, when AC power is supplied to the AC input terminal 1 ′, an inrush current once flows through the capacitor 14 via the rectifier 11 and the inrush current suppressing resistor 13. When the voltage across the terminals of the capacitor 14 rises and the auxiliary power supply section 18 operates, the control circuit 19 is driven to start the on / off operation of the switching transistor 17, and the transformer connected in series with the switching transistor 17 is started.
A rectangular wave voltage is induced in the primary winding 15-1 of 15. As a result, the secondary winding 15-2 of the transformer 15, the tertiary winding 15-3,
A rectangular wave voltage corresponding to the turns ratio is also induced in the fourth winding 15-4. The voltage induced in the secondary winding 15-2 is rectified by the rectifier diode 20, smoothed by the reactor 21 and the capacitor 22, and DC power is output between the output terminals 24-1 and 24-2. Reference numeral 23 is a flywheel diode, which is inserted to circulate a reverse voltage induced in the reactor 21 when the rectifying diode 20 is turned off. On the other hand, tertiary winding
The voltage induced in 15-3 triggers the thyristor 12 to short-circuit the inrush current suppressing resistor 13 described above so that the current during steady operation does not flow through the resistor 13. The fourth winding 15-4 is a switching transistor.
When the transformer 17 is turned off, the excitation energy of the transformer 15 is converted to a diode.
It is for returning to the capacitor 14 via 16 to reset the magnetic flux of the transformer 15.

In such a switching regulator, when the switching transistor 17 is turned on and off at a high frequency, the transformer 15, the reactor 21, and the capacitor 22 can be downsized. Therefore, a multi-output type having a plurality of secondary windings 15-2 and an OA device are provided. It has been widely used as a driving power source for communication equipment and communication equipment, but some OA equipment and communication equipment require uninterrupted power supply. , Its output terminal 24-
Since the DC power output between 1, 24-2 is stopped, conventionally, as shown in FIG. 4, between the AC input terminal 1 ′ of the switching regulator and the AC power source 1, the rectifying device 2, the storage battery 3, The inverter 4 and the synchronous switch 6 having the bypass line 5 and the switch 7 were connected to achieve uninterruption.
However, since the inrush current that flows in the capacitor 14 of the switching regulator at startup reaches several times that in the steady state,
There is a problem that the overcurrent withstanding capacity of the inverter 4 must be increased, and there is a drawback that the overall quality of the OA equipment and communication equipment becomes excessive and the cost becomes high.

An object of the present invention is to eliminate the above-mentioned drawbacks of the present invention. A capacitor for backing up the output of a rectifier that rectifies received AC is backed up by a storage battery, and full-wave rectification or voltage doubler rectification according to an AC input voltage. The purpose of the present invention is to obtain a DC uninterruptible power supply device that can be switched so that it becomes possible to simplify OA equipment and communication equipment as a whole.

Configuration of the Invention The present invention provides a rectifier that rectifies received AC, a capacitor that smoothes the output of the rectifier, a storage battery that backs up the capacitor during an AC power failure, and a trickle charge output to the storage battery when AC power is received. In the DC uninterruptible power supply device having a charger section and a converter for converting DC power from the rectifier or DC power from the storage battery into uninterruptible DC power, the capacitor is 2
Two switches are connected in series, are provided between the series connection point and the rectifier, and are switched to perform full-wave rectification or voltage doubler rectification, and two sets of the storage batteries are provided, and the switch performs full-wave rectification. When a switch is made, the changeover switch is connected in series, and when the switch is switched so as to perform double voltage rectification, the changeover switch is operated so as to be connected in parallel, and the drop of the AC input voltage or the AC power failure is detected. An AC voltage detection unit or a capacitor voltage detection unit is provided, and when the AC input voltage drop or AC power failure is detected by the AC voltage detection unit or the capacitor voltage detection unit, the changeover switch is connected in series with two sets of storage batteries. It is characterized in that it is operated so as to be connected.

Examples Hereinafter, the present invention will be described with reference to Examples.

FIG. 1 is a block diagram of a DC uninterruptible power supply device of the present invention, and parts having the same functions as in FIG.

In FIG. 1, when AC power is supplied to the AC input terminal 1 ', an inrush current flows in the capacitors 14-1 and 14-2 connected in series via the rectifier 11 and the inrush current suppressing resistor 13. When the voltage between the terminals of the capacitors 14-1 and 14-2 rises, the converter 25 operates to output DC power between the output terminals 24-1 and 24-2, and the thyristor 12 is triggered to inrush current. The suppression resistor 13 is short-circuited. When the AC input voltage applied to the AC input terminal 1'is 200V, the switch 26 is turned off and full-wave rectified by the rectifier 11, and when the AC input voltage is 100V, the switch 26 is turned on. The rectifier 11 is configured to perform double voltage rectification. Then, the changeover switch 27 also operates in conjunction with the switch 26, and when the AC input voltage is 200V, 2
The pair of storage batteries 28-1 and 28-2 are connected in series, and when the AC input voltage is 100 V, the two storage batteries 28-1 and 28-2 are connected in parallel. These two sets of storage batteries
28-1 and 28-2 are configured to be connected in series or in parallel depending on whether the AC input voltage is 200 V or 100 V during AC power reception, and trickle charged via the charger unit 29. In addition, the switch unit 30 is turned on by an ON signal sent through the logic circuit unit 33 when the AC voltage detection unit 31 or the capacitor voltage detection unit 32 detects a decrease in the AC input voltage or an AC power failure, whereby the above The changeover switch 27 operates so that the two sets of storage batteries 28-1, 28-2 are connected in series, and the two sets of storage batteries 28-1, 28-2 connected in series are connected.
-2 becomes the DC input power supply of the converter 2, and the output terminals 24-1,
It is configured to obtain uninterrupted DC output between 24-2.

Next, the operation of the DC uninterruptible power supply device of the present invention will be described with reference to the circuit diagram of the embodiment of FIG. Also in FIG. 2, parts having the same functions as those in FIGS. 1 and 3 are designated by the same reference numerals. The AC voltage detection unit 31 includes a diode 50 for rectifying the AC received by the AC input terminal 1 ', a smoothing capacitor 51, resistors 52, 53 for dividing the obtained DC voltage, and a comparator 5
Comparator 54 has a resistor 52,53 at its non-inverting input terminal.
The voltage divided by is applied and the rechargeable battery 28
A reference voltage is applied that keeps the voltage of -1 constant with the resistor 55 and the voltage-stop diode 56, and when the voltage divided by the resistors 52 and 53 falls below the reference voltage, the output becomes L level and an AC power failure is detected. It is configured to be. The capacitor voltage detection unit 32 is composed of resistors 57 and 58 for dividing the voltage across the terminals of the capacitors 14-1 and 14-2, and a comparator 59.
Is output when the reference voltage is applied to its inverting input terminal, the voltage divided by resistors 57 and 58 is applied to the non-inverting input terminal, and the voltage divided by resistors 57 and 58 falls below the reference voltage. Goes to the L level to detect a drop in the voltage between the terminals of the capacitors 14-1 and 14-2, thereby detecting the drop in the AC input voltage. The comparator 5
The outputs of 4,59 are input to the logic circuit section 33 composed of the AND gate 60 and the NAND gate 61, and the output of the AC power failure or the capacitors 14-1, 14-
When any one of the AC input voltage drop due to the drop of the voltage between the two terminals is detected, the output of the logic circuit section 33 is configured to be at the H level, and the H level output is the transistor 62, 63, 64. And a resistor 65 for limiting the collector current of the transistor 62 and the H
The level output turns on the transistor 62, which turns on the transistors 63 and 64.
Operates so as to connect two sets of storage batteries 28-1 and 28-2 in series, and this serves as a DC input power source for the conversion unit 25, and an output terminal
It is configured to obtain uninterrupted DC output between 24-1 and 24-2. The storage batteries 28-1 and 28-2 are diodes 66-1 and 66-2, capacitors 67-1 and 67-2, resistors 68-1 and 68-1, which double-rectify the alternating current received by the alternating current input terminal 1 '.
68-2, whether the AC input voltage is 200V by trickle charging with a smile current by the charger unit 29 including the switch 69.
The switch 69 is turned on and off depending on whether it is 0 V to limit its charging current. Further, the resistor 70 and the constant voltage diode 71 are the above-mentioned comparators 54 and 59, the AND gate 60, the NAND.
This is for supplying drive power to the gate 61.

In the DC uninterruptible power supply device having the above configuration, when the AC input voltage applied to the AC input terminal 1'is 200 V, the storage batteries 28-1 and 28-2 are connected in series so that the AC input voltage is 10 V.
When the voltage is 0V, the storage batteries 28-1 and 28-2 are connected in parallel and trickle charged by the charger unit 29, so a large commercial transformer is used regardless of whether the AC input voltage is 200V or 100V. The charger unit 29 can be shared without the need. Further, even if there is a power outage in which the AC input voltage gradually decreases due to power supply conditions or the like, either the AC voltage detection unit 31 or the capacitor voltage detection unit 32 operates and the storage batteries 28-1, 28-2
Are connected in series to serve as the DC input power source for the conversion unit 25,
It is also possible to prevent an instantaneous drop in the DC output voltage due to operation delay.

In the above-described embodiments of the present invention, the storage batteries 28-1 and 28-2 are Ni-Cd storage batteries having excellent high-rate discharge characteristics connected in series in 110 cells. This is an AC input voltage of 100V, 20
In the case of 0 V, the fluctuation range is ± 10% in both cases, and the minimum value of the voltage between the terminals of capacitors 14-1 and 14-2 is 126%.
V, uninterruptible holding time is 1 minute, terminal voltage after 1 minute at 0 ° C, 10C discharge is 1.15V / cell.
If the trickle charge voltage is 1.5 V / cell, the storage battery 2
When 8-1 and 28-2 are connected in parallel, the voltage is 165 V, and when connected in series, the voltage is 330 V. Therefore, when the AC input voltage is 200 V, the switch 69 is turned off to limit the trickle charging current.

As described in detail in the embodiments of the invention, the present invention is a capacitor for smoothing the output obtained by rectifying the received alternating current, when the AC input voltage is 200V, a storage battery is connected in series, and the AC input voltage is When the input voltage is 100V, the storage batteries are connected in parallel for backup, so even if the AC input voltage is 200V,
Even if it is 0V, it can be shared, and a DC uninterruptible power supply can be configured without an inverter.

[Brief description of drawings]

1 is a block diagram of a DC uninterruptible power supply of the present invention, FIG. 2 is a circuit diagram of the same, FIG. 3 is a circuit diagram of a known switching regulator, and FIG. 4 is a known DC uninterruptible power supply. It is a block diagram. 1 ... AC power supply 1 '... AC input terminal 24-1, 24-2 ... Output terminal 25 ... Converter 26, 29 ... Switch 27 ... Changeover switch 28-1, 28-2 ... Storage battery 29 ...... Charger part 30 ...... Switch part 31 ...... AC voltage detection part 32 ...... Capacitor voltage detection part 33 ...... Logic circuit part

Claims (2)

(57) [Claims] 1. A rectifier for rectifying received AC, a capacitor for smoothing the output of the rectifier, a storage battery for backing up the capacitor during AC power failure, and a charger for supplying trickle charge output to the storage battery during AC power reception. And a converter for converting DC power from the rectifier or DC power from the storage battery into uninterruptible DC power.
Two switches are connected in series, are provided between the series connection point and the rectifier, and are switched to perform full-wave rectification or voltage doubler rectification, and two sets of the storage batteries are provided, and the switch performs full-wave rectification. When the switch is switched so that it is connected in series, when the switch is switched to double voltage rectification, the changeover switch that operates so as to be connected in parallel, and the AC input voltage drop or AC power failure is detected An AC voltage detector or a capacitor voltage detector is provided, and when the AC input voltage drop or AC power failure is detected by the AC voltage detector or the capacitor voltage detector, the changeover switch is connected to two sets of storage batteries in series. A DC uninterruptible power supply characterized by being operated so as to be connected to. 2. A charger for trickle charging a storage battery is provided with a resistor for limiting a trickle charging current, the resistor is inserted during full-wave rectification, and a part of the resistor is short-circuited during double voltage rectification. The DC uninterruptible power supply according to claim 1.