JPS61134819A - Uninterruptive power supply unit - Google Patents

Abstract

PURPOSE:To improve the profitability of an uninterruptive power supply unit by providing a reverse-current preventing means for preventing the charged charge of a capacitor of a smoothing circuit from being discharged to a charging part, when service interruption of an AC power source has occurred. CONSTITUTION:As for an uninterruptive power supply unit, an AC power source Pi is rectified by a rectifying part 1, and through a choke coil 2 and a rectifying circuit of a capacitor 3, a DC output Po is supplied to a DC-AC converting part 4 functioning as a load. Also, at the time of service interruption, from a battery 8 which is always charged through a charging part 7, a thyristor 10 is conducted by a signal by a service interruption detecting part 9, and the power is supplied to said converting part 4. In this case, a diode 11 of a reverse- current preventing means is inserted in series to a rush current limiting resistance 6 of a rush current preventing circuit, and the charging part 7 is connected to the choke coil 2 side through a thyristor switch 13, a rush current limiting resistance 14 and a capacitor 12. In this way, at the time of service interruption, a charged charge of the capacitor 3 is not discharged to the charging part 7, and it is discharged to only said converting part 4.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an uninterruptible power supply device equipped with a storage battery.

For example, in a power supply device that outputs direct current by rectifying and smoothing a commercial power source, if the output cannot be stopped even during a power outage of the commercial power source, a storage battery is often installed. In such an uninterruptible power supply, the capacitor constituting the smoothing circuit should have as small a capacity as possible without reducing the output voltage until direct current is output from the storage battery, which improves the economic efficiency of the uninterruptible power supply. desired for the sake of

[Conventional technology]

FIG. 2 is a diagram showing an example of a conventional uninterruptible power supply system. In FIG. 2, an AC power supply Pi is rectified by a rectifier 1 and smoothed by a smoothing circuit composed of a blocking wire 2 and a capacitor 3 to generate a DC output Pa. is supplied to. Note that an inrush current prevention circuit composed of a silisk switch 5 and an inrush current limiting resistor 6 is inserted between the blocking wire 2 and the capacitor 3. The thyristor switch 5 limits the charging current of the capacitor 3 by the inrush current limiting resistor 6 by setting it in a cut-off state until the capacitor 3 is charged after the AC power supply Pi is turned on. The DC output Po is also supplied to the storage battery 8 via the charging unit 7 to maintain and charge the storage battery 8.

The power outage detection unit 9 monitors the supply state of the AC power supply Pi, and when the AC power supply Pi is being supplied, sets the si-risk switch IO to the cutoff state. As a result, even if the terminal voltage Vc of the capacitor 3 fluctuates below the storage battery voltage vb, the storage battery 8 is not discharged and is maintained in the maintained charged state.

If the AC power supply Pi fails in this state, power will no longer be supplied from the rectifier 1 to the smoothing circuit. On the other hand, when the power failure detection unit 9 detects a power failure in the AC power supply Pi, it immediately sets the thyristor switch 10 to a conductive state. As a result, the DC output PO is supplied from the storage battery 8 to the DC/AC converter 4. After power outage of AC power supply Pi, Cyrisk switch 1
0 is in a conductive state and the charge in the capacitor 3 is supplied to the DC/AC converter 4 until the storage battery 8 starts supplying the DC output po. Note that the terminal voltage Vc of the capacitor 3 must be maintained at a specified value or higher until the DC output Po can be supplied from the storage battery 8, and a large capacity is required. Furthermore, since both ends of the capacitor 3 are connected in parallel to the charging section 7 in addition to the DC/AC converting section 4, the charging charge is supplied not only to the DC/AC converting section 4 but also to the charging section 7. The required capacity of the capacitor 3 is further increased.

[Problem that the invention seeks to solve]

As is clear from the above explanation, in conventional uninterruptible power supplies, the capacitor 3 constituting the smoothing circuit is connected not only to the DC/AC converter 4 that is the load but also to the charging unit 7. , a large capacity is required to maintain the terminal voltage VC of the capacitor 3 above the specified value from the time when the source Pi is out of power until the DC output PO is started being supplied from the storage battery 8.
There is a risk that the economic efficiency of the uninterruptible power supply will be impaired.

[Means for solving problems]

The problem is that there is a rectifier that rectifies the AC power source, a smoothing circuit that smoothes the output of the rectifier, a storage battery that is charged by the output of the rectifier via the charging unit, and a The problem is solved by the present invention, characterized in that: and a backflow prevention means for preventing discharge of the charge of a capacitor constituting the smoothing circuit to the charging section.

[Effect]

That is, according to the present invention, there is no possibility that the charge in the capacitor constituting the smoothing circuit will be discharged via the charging section that charges the attached storage battery, and the charge in the capacitor is discharged only as a DC output. , the capacitor needs only a small capacity, which improves the economic efficiency of the uninterruptible power supply.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing an uninterruptible power supply according to an embodiment of the present invention. Note that the same reference numerals indicate the same objects throughout the figures.

In FIG. 1, a diode 1 is connected as a backflow prevention means in series with an inrush current limiting resistor 6 constituting an inrush current prevention circuit.
1 is inserted, and the charging section 7 is not connected from both ends of the capacitor 3, but is connected from the connection point between the blockage wire 2 and the inrush current prevention circuit, and the charging section 7 is connected to the charging section consisting of the thyristor switch 13 and the inrush current limiting resistor 14. A dedicated inrush current prevention circuit is connected to the section 7, and a dedicated capacitor 12 is connected to the charging section 7.

In FIG. 1, while AC power Pi is being supplied,
The DC output Po is supplied (Q) to the DC/AC converter 4 via the rectifier 1i and the smoothing circuit as in FIG. 2 and a capacitor 12, a direct current is input thereto.

When the AC power supply Pi loses power in such a state, the charge in the capacitor 3 is transferred to the DC/AC converter 4 as in FIG.
is discharged against. It should be noted that the capacitor 3 is connected to the charging section 7 via the thyrisk switch 5 and the diode 11, but since both are in the opposite direction, the charge in the capacitor 3 is not discharged via the charging section 7. . Eventually, the power outage detection unit 9 sets the SIRISK switch 10 to a conductive state, and the storage battery 8 starts supplying the DC output Po.

As is clear from the above description, according to this embodiment, when the AC power supply Pi is out of power, the charge in the capacitor 3 is discharged only to the load, and the terminal voltage Vc
It becomes possible to maintain the specified value for a long time, and the capacity of the capacitor 3 can also be reduced, making it possible to improve the economical efficiency of the uninterruptible IIS device.

Note that FIG. 1 is only one embodiment of the present invention, and for example, the load of the DC output PO is not limited to the DC/AC converter 4, and many other modifications may be considered, but any The effect of the present invention does not change even in this case.

〔Effect of the invention〕

As described above, according to the present invention, in the uninterruptible power supply device,
There is no longer any possibility that the charge on the capacitor that makes up the smoothing circuit will be discharged via the charging section that charges the attached storage battery, and the charge on the capacitor will be discharged only as a DC output, so the terminal voltage of the capacitor will be The standard value is sufficiently maintained until the DC output starts being supplied from the storage battery, and the capacity of the capacitor is small, improving the economic efficiency of the uninterruptible power supply.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an uninterruptible power supply according to an embodiment of the present invention, and FIG. 2 is a diagram showing an example of a conventional uninterruptible power supply. In the figure, l is a rectifier, 2 is a blockage ring, 3 and 12
is a capacitor, 4 is a DC/AC converter, 5.10 and 1
3 is a thyristor inch, 6 and 14 are inrush current limiting resistors, 7 is a charging section, 8 is a storage battery, 9 is a power failure detection section, 11
is a diode, Pi is AC1li8. P o is a DC output, vb is a storage battery voltage, and VC is a terminal voltage.

Claims (1)

[Claims] a rectifying section that rectifies an AC power source; a smoothing circuit that smoothes the output of the rectifying section; a storage battery that is charged via a charging section by the output of the rectifying section; 1. An uninterruptible power supply device comprising a backflow prevention means for preventing discharge of charges of a constituting capacitor to the charging section.