JPH0527327B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention can be connected to either a three-phase, three-wire AC power system (or power source) or a three-phase, four-wire AC power system (or power source). related to electronic devices.

[Background of the invention]

In the United States, a 3-phase, 3-wire AC power system (200V system) is used, while in the states of the state, a 3-phase, 4-wire AC power system (400V system) is used. Therefore, it is desirable that electronic devices exported to these countries be designed in advance so that they can be connected to any power system.

Conventionally, such power equipment connects units such as internal power supplies to a 3-phase 3-wire AC power system (or 3-wire AC power system).
In the case of a 3-phase 3-wire AC power system (or 3-phase 4-wire AC power system), it is designed so that it can be connected to a 3-phase 3-wire AC power system. In the case of a 4-wire AC power system (or 3-phase 3-wire system), power is supplied to the internal unit via a transformer for converting 3-phase 4-wire system to 3-phase 3-wire system (or vice versa). That's what I do. However, when such a conversion transformer is built into or attached to an electronic device, there are disadvantages in that it increases the size of the electronic device, increases the installation space, and increases the price.

[Purpose of the invention]

An object of the present invention is to provide an electronic device that can be connected to either a three-phase, three-wire AC power system or a three-phase, four-wire AC power system, which eliminates the above-mentioned drawbacks.

Other objects and effects of the present invention will become clear in the following description.

Note that in this specification, the term "power system" is used to include an independent "power source."

[Summary of the invention]

Among the internal units of electronic devices that are connected to and operate on an AC power system, the type of AC power system is a problem for units that are supplied with AC power, such as power supplies. It is easy to configure it to operate on either phase AC power or single phase AC power. For example, a switching type stabilized DC power supply device using a three-phase bridge rectifier circuit in its input stage operates when supplied with either three-phase AC power or single-phase AC power.

Focusing on these points, the present invention aims to provide an electronic device that can be connected to either a 3-phase 3-wire power system or a 3-phase 4-wire power system without using a conversion transformer. .

Accordingly, the electronic device according to the present invention includes a unit such as one or more power supplies having three AC power terminals and capable of operating on either three-phase AC power or single-phase AC power, and a three-phase three-wire type AC power system or 3
No. 1 for connecting each phase line of a three-wire AC power system.
connection of the first to third power receiving terminals, the fourth power receiving terminal for connection of the neutral line of the three-phase four-wire AC power system, and the first to fourth power receiving terminals to the AC power terminal of the unit; If a three-phase three-wire AC power system is connected to the first to third power receiving terminals, the connection switching device switches the first to third power receiving terminals. Each is connected to a corresponding one of the three AC power terminals of the unit, the unit operates on three-phase AC power, and a three-phase four-wire AC power system is connected to the first to fourth power receiving terminals. In this case, the connection switching device selects one of the first to third power receiving terminals.
The first and fourth power receiving terminals are each connected to a specific AC power terminal of the unit, and the unit is configured to operate on single phase power.

Further, according to the present invention, when a three-phase four-wire AC power system is connected, a reactor for power factor improvement is inserted in series between the fourth power receiving terminal and the AC power terminal of the unit connected to it. be done.

[Embodiments of the invention]

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

FIG. 1 is a block diagram showing one embodiment of the present invention. In this figure, 1 is an electronic device according to the present invention, which includes three internal units 2, 3, 4, a connection switching device 5, a power switch 6, and a power receiving terminal 7.
~10.

Units 2, 3, and 4 are the above-mentioned switching type stabilized DC power supplies that operate when supplied with either three-phase AC power or single-phase AC power, and each unit has three AC power terminals 11 to 19. has.

The connection switching device 5 has input terminals 20 to 23 and output terminals 24 to 29, and also has output terminals 24 and 2.
6, 28 and means for fixedly connecting the input terminals 20, 21, 22, respectively, and the output terminals 25,
27, 29 and input terminals 20 to 23 are provided with means for switching and connecting them as shown by broken lines or chain lines in the figure. The latter means may consist, for example, of a manually or electromagnetically driven mechanical switch, or an electronic switch operated by an electrical signal.

The input terminals 20 to 23 of the connection switching device 5 are connected to the power receiving terminals 7 to 10 through the contacts of the power switch 6, respectively, and the output terminals 24 to 29 are connected to the AC power terminals 11 to 10 of the units 2 to 4 as shown in the figure. Connected to 19.

The power receiving terminals 7, 8.9 are for connecting the R, S, and T phase lines of a 3-phase 3-wire AC power system, or the U, V, and W phase lines of a 3-phase 4-wire AC power system. The power receiving terminal 10 is a terminal for connecting a neutral line of a three-phase four-wire AC power system.

To explain the operation, when the electronic device 1 is connected to a three-phase three-wire AC power system, the output terminals 25, 27, 2 are switched by the switching connection means of the connection switching device 5.
9 is connected to input electrons 20 to 23 as shown by broken lines. Therefore, when each contact of the power switch 6 is closed, the units 2, 3, and 4 are connected to their AC power terminals with a three-phase, three-wire AC power system, and operate on three-phase AC power.

When using the electronic device 1 by connecting to a 3-phase 4-wire AC power system, the output terminal 2 of the connection switching device 5
Connections between input terminals 5, 27, and 29 and input terminals 20 to 23 are switched as shown by chain lines. Therefore, units 2, 3, and 4 each have 3 connected to their AC power terminals.
One phase line of a phase 4-wire AC power system is connected to the neutral line, and it operates with single-phase AC power.

As described above, the electronic device 1 of this embodiment can be connected to either a 3-phase 3-wire system or a 3-phase 4-wire AC power system; First, the unit's AC power terminals 11-- which can operate on either three-phase or single-phase AC power.
19 and the power receiving terminals 7 to 10 are switched by a simple connection switching device 5, and even when using a conversion transformer, a similar connection switching device is required. It can be realized in a small size and at low cost.

FIG. 2 is a block diagram showing another embodiment of the invention. In the electronic device 1' of this embodiment, the reactor 30 for power factor improvement is connected to the input terminal 23 and the power receiving terminal 1.
This differs from the electronic device 1 of the above embodiment in that the electronic device 1 is inserted between the power switch 6 and the power switch 6 through the contact point.

The operation is exactly the same as the device of the above embodiment when connected to a 3-phase 3-wire AC power system, but when connected to a 3-phase 4-wire AC power system, the power receiving terminal 10 is connected via a reactor. unit 2,
It is connected to specific AC power supply terminals 3 and 4 to improve the power factor.

Other objects and effects of the present invention will now be explained.

The simplest configuration of an electronic device that can be connected to either a 3-phase 3-wire or 3-phase 4-wire AC power system is one in which units such as power supplies inside the electronic device are operated with single-phase AC power. Designed to 3
When connecting to a three-phase, four-wire AC power system, connect the lines of any two phases to the AC power terminals of the unit; when connecting to a three-phase, four-wire AC power system, connect the lines of one of the phases to the A possible configuration is such that the line and neutral line are connected to the AC power terminal of the unit. Compared to such a configuration, the present invention provides the following benefits.

In the above configuration where the internal unit always operates on single-phase AC power, the applied voltage to the internal unit is 200V when connected to a 3-phase 3-wire AC power system.
~240V, when connected to a 3-phase 4-wire AC power system
219.4V to 239.6V, and the minimum operating voltage of the internal unit must be lowered to 200V. On the other hand, since the minimum operating voltage of the internal unit in the electronic device according to the present invention is only 219.4V, the power supply voltage margin of the internal unit can be narrowed by 9% (=200V/219.4V). Therefore, it is possible to reduce the size and cost of the internal unit.

Furthermore, since the switching type stabilized DC power supply has an extremely poor power factor, a filter consisting of a reactor and a capacitor is installed after the rectifier circuit to improve the power factor. However, when large-capacity switching type stabilized DC power supplies with DC output such as 5V100A and 5V300A are operated with single-phase AC power, it is difficult to achieve sufficient power factor improvement with such a filter. The physical size becomes significantly large, and the power supply device becomes large and expensive, which is difficult in practice. For this reason, it is necessary to insert a reactor before the power supply to improve the power factor, but if the internal unit is always operated with single-phase AC power, a reactor must be inserted in each phase of the AC power system. Furthermore, because the voltage drop caused by the reactor occurs in each phase, the voltage drop seen from the internal unit becomes twice as large, which greatly limits the reactors that can be used, making it difficult to achieve a sufficient power factor improvement effect. is extremely difficult.

On the other hand, according to the present invention, as in the embodiment shown in FIG. Connect units 2, 3, and 4 as in the example, and
If the current of each phase of W is approximately balanced, reactor 3
Even if a small and inexpensive device is used as zero, sufficient power factor improvement can be achieved. Note that when connecting to a 3-phase 3-wire AC power system, the reactor 30 does not work, but in this case, units 2, 3, and 4 are operated with 3-phase AC power, so there is no need to insert a reactor externally. However, it is possible to sufficiently improve the power factor inside the unit, and this does not pose a particular problem.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, an electronic device that can be connected to either a three-phase three-wire system or a three-phase four-wire AC power system can be connected to an electronic device that uses a conversion transformer, and Compared to electronic devices that constantly operate internal units using single-phase AC power, the advantage is that they can be realized in a smaller size and at a lower cost.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the invention, and FIG. 2 is a block diagram showing another embodiment of the invention. 1...Electronic device, 2-4...Unit, 5...
Connection switching device, 6... Power switch, 7 to 10...
...Power receiving terminal, 11-19...AC power supply terminal, 30
...Reactor.

Claims (1)

[Claims] 1. A unit such as one or more power supplies having three AC power terminals and capable of operating on either three-phase AC power or single-phase AC power, and a three-phase three-wire AC First to third power receiving terminals for connecting each phase line of a power system or a three-phase three-wire AC power system, and a three-phase four
A fourth power receiving terminal for connecting a neutral line of a wire type AC power system, and a connection switching device for switching the connection between the first to fourth power receiving terminals and the AC power terminal of the unit, When a three-phase three-wire AC power system is connected to the first to third power receiving terminals, the connection switching device
The power receiving terminals of the units are each connected to a specific AC power terminal of the unit, the unit operates on three-phase AC power, and a three-phase four-wire AC power system is connected to the first to fourth power receiving terminals. In this case, the connection switching device connects any one of the first to third power receiving terminals and the fourth power receiving terminal to a specific AC power terminal of the unit, and the unit is connected to single-phase power. An electronic device that operates on 2. The electronic device according to claim 1 further includes a reactor, and when a three-phase four-wire AC power system is connected, the connection switching device connects the reactor to the fourth power receiving terminal. An electronic device characterized in that it is inserted in series between a specific AC power terminal of the unit connected thereto.