JPH0225910A - Power unit - Google Patents

Abstract

PURPOSE:To realize the use of an external power supply battery in case an AC power supply has an unexpected situation by converting the voltage of an external DC power supply into the prescribed DC voltage value via a DC/DC conversion means and then converting the DC voltage into the prescribed AC voltage value via a DC/AC conversion means. CONSTITUTION:When the absence of an AC power supply is judged by a voltage drop detecting means 9, a control means 8 switches an output switch means 13 to the output side of a DC/AC converter 12. At the same time, the means 8 controls the working of the converter 12 via an interface means 15. The DC power supply voltage applied to a DC/DC converter 11 is converted into a prescribed high DC voltage level and applied to the converter 12 to be converted into the AC voltage. This AC voltage is fed back to the means 8 via an interface means 16 and turned into a stabilized AC output. Thus an AC power supply having the voltage drop is immediately replaced with an external power supply.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a power supply device for constantly supplying power to a load, and more specifically, to a power supply device for constantly supplying power to a load. The present invention relates to a power supply device that can be used with either a DC power source such as an external battery or an AC power source from a commercial line.

[Conventional technology]

When using a load that is driven by AC, for example outdoors, where AC power is not available, the DC voltage of the battery is converted to AC voltage using a switching circuit, and the voltage is boosted to a predetermined voltage level using a step-up transformer. BACKGROUND ART A power supply device is used that feeds back voltage to a switching circuit to control the switching circuit and output a stable alternating current voltage.

On the other hand, when power is obtained from a commercial AC line and AC power is constantly supplied to the load, even if the AC line voltage drops, the output side maintains the specified AC output without voltage drop or power outage. Therefore, AC output is applied to the load via an uninterruptible power supply. In such an uninterruptible power supply n, the input terminal connected to the commercial AC line is separated into a built-in battery charging section and an AC output,
The output side of the built-in battery charging section is connected to a DC-AC inverter that converts this DC output voltage into an AC voltage. The DC-AC inverter is controlled by a control section composed of a microcomputer or the like. This controller controls whether the voltage applied to the output terminal is AC voltage from the input terminal or
It also controls a switching section that switches between AC voltage and AC voltage from the DC-AC inverter. The ffl source is supplied to the load by constantly monitoring the AC input voltage from the input terminal in the control unit, and applying the AC voltage from the input terminal to the output terminal while the AC input voltage from the input terminal maintains a predetermined value. The output switching unit is switched so that the voltage drops below a predetermined value, the output switching unit is immediately switched to the DC-AC inverter side, and the AC voltage from this inverter is controlled to be applied to the output terminal. .

[Problem to be solved by the invention]

The former power supply device uses only batteries as a power source, so it is convenient in places where AC power is not readily available as mentioned above, but even when used in places where AC power is easily available. , it is not possible to switch the supply source to alternating current, and the user is forced to use batteries, etc., which gradually wear out. In addition, the latter type of uninterruptible power supply charges the built-in battery with power from the commercial AC line, and when the power from the commercial AC line becomes low or there is a power outage, power is obtained from the built-in battery. Since a high-voltage battery is used, there is a drawback that the entire device becomes large in size, and at the same time, during a long power outage, the built-in battery may discharge and cease to function as a power source. To prevent this, you can use a large capacity battery, but is it possible to do so without interruption? t
The LTFI source device has become even larger and cannot be easily installed. Particularly when the uninterruptible power supply is mounted on a vehicle and a predetermined measurement is to be carried out over a long period of time at a moving destination, it is impossible to mount a large uninterruptible power supply.

Therefore, the purpose of this invention is to use AC power as a supply source in places where AC power is available, and to switch the supply source to DC power in places where AC power cannot be obtained, and to use AC power. To provide a power supply device that can always supply a constant supply voltage by immediately switching to a DC power supply when a situation such as a voltage drop or a power outage occurs in an AC power supply.

Another object of the present invention is to provide a compact, inexpensive power supply device with an uninterruptible function that allows the use of an external power source battery when an unexpected situation occurs in the AC it fK.

Still another object of the present invention is to provide a power supply device with an uninterrupted ff1l capability capable of outputting 200 V, which has been attracting attention in recent years.

[Means to solve the problem]

The power supply device of the present invention includes a DC-DC conversion means for converting the voltage of an external DC power supply into a predetermined DC voltage value, and
A DC-AC conversion means that converts the output voltage of the DC conversion means into an AC of a predetermined voltage value, a transformer that converts and divides the AC voltage from the AC source into DC voltage, and converts the AC voltage from the DC-AC conversion means and the AC a switching means for switching either one of the AC voltage from the source to appear at the output terminal; and a switching means that operates with the voltage from either the external DC power source or the transformer, and monitors voltage fluctuations of the AC source; When the voltage drops below a preset value, operate the switching means to switch the output terminal to DC-AC.
The invention is characterized in that it has a control means for switching to output an alternating current voltage from the conversion means.

In addition to the above configuration, the output side of the transformer is further provided with a charging unit for charging the battery, and the battery is connected to DC-D via a relay that is controlled by an external DC power source to prevent its discharge.
The second object of the invention is achieved by connecting the control means to the C conversion means so as to be operated by the voltage from the battery.

Furthermore, the third object of the present invention is achieved by connecting a high voltage transformer between the DC-AC converting means and the switching means to these configurations, which converts the output voltage of the DC-AC converting means to a predetermined high voltage. be done.

〔Example〕

Hereinafter, embodiments of the present invention shown in the drawings will be described.

First, the first embodiment shown in FIG. 1 will be described. This power supply device has an AC input terminal 1 connected to a commercial AC line and a DC input terminal 2 connected to an external DC power source such as a battery. ing.

The primary side of a transformer 3 is connected to the AC input terminal 1, and the secondary side of the transformer 3, which has been converted to a predetermined voltage level, is connected to a control system described later to detect a drop in the AC input voltage. It is isolated and separated into a detection system for the detection system. For the control system on the secondary side of transformer 3.

The input side of rectifying and smoothing means 4 that converts AC input voltage into DC voltage is connected. The output side of the rectifying and smoothing means 4 is connected to the input side of the constant voltage control means 6 via a diode 5 for preventing backflow. A DC input terminal 2 is also connected to the input side of the constant voltage control means 6 via a diode 7 for preventing backflow. This constant voltage control means 6 controls so as to always supply a constant voltage to the control means 8 connected to its output side. The input side of a voltage drop detection means 9 that detects whether the AC input voltage has fallen below a specified voltage value is connected to the detection system on the secondary side of the transformer 3, and the output side thereof is connected to the input terminal of the control means 8. It is connected to the.

The input side of the DC input terminal 2 is connected to a DC-DC converter 11 that converts the input DC voltage into a predetermined high voltage DC voltage, for example, 141 V when a 12V external battery is used. The output voltage level of the DC-DC converter 11 is approximately the peak value of a desired AC voltage. DC-
The output side of the DC converter 11 is a DC-AC converter 1 that converts the high voltage DC voltage obtained by the converter 11 into an AC voltage.
2 to the input side of the output switching means 13. The AC input terminal 1 is also connected to the input side of the output switching means 13, and either the AC output voltage from the DC-AC converter 12 or the commercial AC voltage from the AC input terminal 1 is selected at the output terminal 14. apply.

A control means 8 composed of a microcomputer or the like is connected to the output switching means 13, and when the AC input voltage from the voltage drop detection means 9 is at a specified voltage value, it outputs the commercial AC voltage from the AC input terminal 1. 14, when a signal indicating that the AC input voltage has fallen below a specified voltage value is applied, the AC output voltage from the DC-AC conversion @iz is switched to the AC output voltage side and the AC voltage is sent to the output terminal 14. The output switching means 13 is switched as shown in FIG. The control means 8 are also connected to the DC-AC converter 12 via the interface means 15 and control the conversion of the DC-AC converter 12. This interface means 15 is composed of an electrically insulated photocoupler or the like. This control means 8
The output of the DC-AC converter 12 controlled by is fed back to the control means 8 via another interface means 16 connected to its output side, and
controls stabilization of the AC output voltage of the DC-AC converter 12. This interface means 16 is composed of an electrically insulated transformer or the like. The control means 8 includes a lamp or the like to indicate that external power is being taken from the DC input terminal 2 in the event that the commercial AC voltage from the AC input terminal 1 becomes lower than a specified value or there is a power outage. AC disconnection display means 17 is connected.

When this power supply device is used in a place where power cannot be obtained from a commercial AC line, an external battery, such as a car battery, is connected to the DC input terminal 2.

The DC power supply voltage of the external battery is controlled by the constant voltage control means 6 and DC
− applied to the DC converter 11; After the constant voltage control means 6 sets the voltage to a predetermined voltage value, it is applied to the control means 8 as a related power supply voltage to operate the control means 8. The control means 8 determines that there is no AC power supply by the voltage drop detection means 9, and switches the output switching means 13 to the output side of the DC-AC converter 12, and also switches the output switching means 13 to the output side of the DC-AC converter 12, and also switches the output switching means 13 to the output side of the DC-AC converter 12.
Controls the conversion operation of the C converter 12. The II current voltage applied to the DC-DC converter 11 is converted into a predetermined high-voltage DC voltage, and then applied to the DC-AC converter 12, where it is converted into an AC voltage. The converted alternating current voltage is fed back to the control means 8 via the interface means 16, and is controlled to provide a stabilized alternating current output. The AC voltage stabilized in this way is output from the output switching means 13 to the output terminal 14.

When used in a place where power can be obtained from a commercial AC line, connect the commercial AC line to the AC input terminal 1, and the AC voltage will be converted to a voltage level by the transformer 3.
After being converted into a DC voltage by the rectifying and smoothing means 4, it is applied as a driving voltage to the control means 8 via the constant voltage control means 6. The commercial AC voltage at AC input terminal 1 is
A voltage drop detection means 9 connected to the next side constantly monitors whether the voltage has fallen below a specified value and outputs the information to the control means 8. When the commercial AC voltage is normal, the control means 8 switches the output switching means 13 to the AC input terminal 1 side. As a result, the commercial AC voltage is applied to the output terminal I4. In this case, if an external battery is connected to the DC input terminal 2, if the commercial AC voltage drops below the specified voltage value or there is a power outage, the voltage drop detection means 9 will quickly detect this condition.
The control means 8 connects the output switching means 13 to the DC-AC converter 12.
Therefore, the output terminal 14 can always output a predetermined AC voltage.

The second embodiment of the present invention shown in FIG. 2 is designed to obtain AC voltage using a built-in rechargeable battery or an external battery when the commercial AC voltage becomes low or there is a power outage. AC voltage can also be obtained from these built-in rechargeable batteries and external batteries. Note that the same components as in the first embodiment described above are indicated by the same reference numerals, and the explanation thereof will be omitted. A transformer 21 similar to the transformer 3 is connected to the input terminal 1 which is connected to a 200 V commercial AC line. The secondary side of this transformer 21 is insulated and divided into three parts and converted to an appropriate voltage level, and each part is connected to a rectifying and smoothing means 4.degree. voltage drop detection means 9 and a charging section 22. A backflow prevention diode 23 is connected between the DC input terminal 2 and the DC-DC converter 11. DC input terminal 2 has
By connecting an external battery or the like to this terminal 2 and applying a DC voltage.

A relay 24 is connected which opens the contacts, and this relay 24
A rechargeable built-in battery 25 is connected to. The battery 25 is connected to the input side of the DC-DC converter 11 via the contacts of the relay 24 and the backflow prevention diode 26. The output side of charging section 22 is connected to the input side of diode 26 via diode 27 for preventing backflow. Therefore, while the contacts of relay 24 are closed,
The battery 25 is charged by the output of the charging section 22. The input side of the DC-DC converter 11 and the constant voltage control means 6
A backflow prevention diode 28 is connected between the input sides of the
This allows the constant voltage control means 6 to operate using any of the DC voltage from the rectifying and smoothing means 4, the DC voltage of the external battery from the DC input terminal 2, and the charging DC voltage of the battery 25. . The DC-AC converter 12 is connected between the DC-ACC converter 12 and the output switching means 13.
A transformer 29 is connected to boost the voltage from AC 100V to 200V.

In this embodiment, if a 200 V commercial AC line is connected to the AC input terminal 1, then the output terminal 1
The AC voltage is outputted to 4.

Unless an external battery is connected to the DC input terminal 2, no voltage will appear at the DC input terminal 2, so the contacts of the relay 24 are closed, so that the AC voltage applied to the AC input terminal 1 is transferred from the transformer 21. Battery 2 via charging section 22
It is charged to 5. When the commercial AC voltage drops below a specified voltage value or there is a power outage, the voltage drop detection means 9 promptly detects this condition, and the control means 8 switches the output switching means 13 to the output side of the DC-AC converter 12. Switch. As a result, the DC voltage charged in the battery 25 is input to the DC-DC converter 11 via the relay 24 and the diode 26, and is also input to the constant voltage control means 6 via the diode 26 and the diode 28. The operation of the control means 8 never stops. The DC voltage input to the DC-DC converter 11 is converted to a high voltage of 100v, and then converted to DC-DC.
The AC converter 12 converts the voltage into an AC voltage of 141V.

This AC voltage is applied to the transformer 29 to step up the AC voltage from 100 V to 200 V, and then is output to the output terminal 14 via the output switching means 13.

If an external battery is connected to DC input terminal 2, relay 2
4 opens the contact to disconnect the battery 25 and prevent over-discharge. Since the other operations are the same as those in the first embodiment, their explanation will be omitted. In addition, when the power outage is short, the built-in battery 25 provides assistance, and after that, the external battery is used. l
Since the built-in battery 25 can have a small capacity, the built-in battery 25 only needs to have a small capacity.

This allows the entire power supply device to be made smaller.

In this second embodiment, the voltage is for a 200v commercial AC line, but since the DC-AC converter 12 converts the voltage into a 100v AC voltage, the output is directly transferred to the output switching means 13.
By removing the transformer 29 so as to connect to the current 100V commercial AC line, the present invention can be applied to the current 100V commercial AC line. Therefore, depending on the presence or absence of the transformer 29, it can be provided for use on a 200V commercial AC line or for a 100V commercial AC line.

〔Effect of the invention〕

As described above, the power supply device of the present invention converts the voltage of an external DC power supply into a predetermined DC voltage value using the DC-DC conversion means,
By converting the output voltage of this DC-DC conversion means into an alternating current of a predetermined voltage value by the DC-AC conversion means, for example, a car battery or the like can be used as an external DC power source, so that an AC power source is not readily available. AC voltage can be supplied to loads even in locations. Furthermore, if a voltage drop occurs in the AC power supply while supplying AC to the load using the AC power supply, it is possible to immediately switch to an external power supply, so a stable AC voltage can always be supplied to the load. .

According to the second aspect, the built-in battery can be charged when the AC power source is used, and when a voltage drop occurs in the AC power source, power can be immediately supplied from the battery. Furthermore, it can be connected to an external DC power supply, so if the voltage drop of the AC power supply lasts for a long time, it can be switched to take power from the external DC power supply, so the built-in battery does not need to have a small capacity. This allows the power supply device to be downsized.

Furthermore, as claimed in claim 3, 1) a high-voltage AC power source of, for example, 200 V can also be obtained by simply adding a high-voltage transformer that converts the voltage to a predetermined high voltage to the output side of the C-AC conversion means; I can do it. Since this high voltage is boosted after converting a DC voltage into an AC voltage, the structure of the transformer is simple and can be provided at low cost.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a first embodiment of the invention, and FIG. 2 is a block diagram showing a second embodiment. In the drawing, 1 is an AC input terminal, 2 is a DC input terminal,
3.21 is a transformer, 4 is a current smoothing means, 5°7, 23
．． 26, 27, 28 are reverse current prevention diodes, 6 is a constant voltage control means, 8 is a control means, 9 is a voltage drop detection means, 1
1 is a DC-DC converter, 12 is a DC-AC converter, 13
14 is an output terminal, 15° and 16 are interface means, and 17 is an AC disconnection display means. 22 is a charging part, 24 is a relay, 25 is a built-in battery, 2
9 is a transformer. Patent filing filed by NichifiIffi Ki Co., Ltd. Patent attorney Takuya Ohara

Claims (3)

[Claims] (1) A power supply device that constantly supplies an AC voltage to a load, which includes a DC-DC conversion means that converts the voltage of an external DC power supply to a predetermined DC voltage value, and an output voltage of the DC-DC conversion means to a predetermined voltage. a DC-AC converter for converting the AC voltage from the AC source into a DC voltage; a transformer for converting and dividing the AC voltage from the AC source into DC voltage; a switching means for switching so that either one appears at the output terminal, and is operated by a voltage from either the external DC power supply or the transformer,
Control that monitors voltage fluctuations of the AC source and, when the voltage drops below a preset value, operates the switching means to switch to output the AC voltage from the DC-AC conversion means to the output terminal. A power supply device comprising: means. (2) The output side of the transformer is provided with a charging unit that charges a battery, and the battery is connected to the D
2. The power supply device according to claim 1, wherein the power supply device is connected to a C-DC conversion means, and the control means is connected so as to be operated by voltage from the battery. (3) A high voltage transformer for converting the output voltage of the DC-AC converting means to a predetermined high voltage is connected between the DC-AC converting means and the switching means. Alternatively, the power supply device according to any one of 2.