JP3888331B2 - High frequency noise suppression device for uninterruptible power supply - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a high-frequency noise suppression device for an uninterruptible power supply that can suppress high-frequency common mode noise when a power converter and a battery are housed in separate panels.
[0002]
[Prior art]
For example, an electronic device such as a computer must be avoided even in the case of a power failure for a very short time. Therefore, when such a device is used, an uninterruptible power supply is often installed between the device and a commercial power source. The uninterruptible power supply includes a converter that converts AC power from a commercial power source into DC power, an inverter that converts DC power from the converter into AC power and supplies power to a load, and these converters. And a battery that backs up the power failure by connecting to the DC intermediate circuit that connects the DC sides of the inverter.
[0003]
Inverters generally convert DC power into AC power by pulse width modulation control of semiconductor switching elements such as transistors. In some cases, converters also use diode rectifiers to obtain DC power. Similarly, DC power is often obtained by pulse width modulation control of semiconductor switch elements such as transistors. The carrier frequency during this pulse width modulation control has become higher in recent years because it improves the performance of the switching element and improves the control accuracy, and as a result, more high-frequency noise is generated. ing. Therefore, in order to suppress common mode noise generated between the converter and the inverter due to the switching operation, the common mode is a magnetic circuit common to the power supply side circuit and the load side circuit of the power converter. Insert the chalk. Or the invention which inserts the common mode choke which is a magnetic circuit common to the three of the power supply side circuit of a power converter, a load side circuit, and a battery circuit is proposed (for example, refer to patent documents 1).
[0004]
However, as the capacity of the uninterruptible power supply has increased with the increase in capacity of the load, the capacity of the battery that backs up the power failure of the commercial power supply has also increased. Furthermore, when it is necessary to cover a long-time power outage, the battery must be further increased in capacity, so it is necessary to store the power converter and the battery in the same panel both from the outside dimensions and from the mass. It becomes difficult. Therefore, both are housed and installed in separate boards.
FIG. 2 is a main circuit configuration diagram showing a conventional example for suppressing common mode noise of an uninterruptible power supply device configured to be separated into a power converter panel and a battery panel. In this conventional circuit, the power converter constituted by the converter 3 and the inverter 4 is housed in the power converter board 2, but the battery 7 is housed in a separate battery board 6. The positive and negative conductors 8 are connected. Reference numeral 1 is a commercial power source, and reference numeral 5 is a load.
[0005]
When the power converter board 2 and the battery board 6 are installed separately as described above, the ground terminals 12 and 16 are provided on the power converter board 2 and the battery board 6, respectively. If the electrostatic capacity of the battery panel 6 is larger than that of the power converter panel 2, the ground from the ground terminal 16 of the battery panel 6 to the ground is connected to the ground. The wiring 17 is used. Further, by passing the positive and negative conductors 8 through the first common mode core 10, it is possible to prevent the high-frequency noise generated due to the switching operation of the converter 3 and the inverter 4 from flowing out to the battery 7. These measures have conventionally prevented leakage of common mode noise from the uninterruptible power supply to the outside.
[0006]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 11-98716
[Problems to be solved by the invention]
However, in the conventional circuit shown in FIG. 2, when the stray capacitance increases as the capacity of the battery 7 increases, the high-frequency impedance between the ground and the ground decreases. Will increase. Therefore, the first common mode core 10 must be enlarged.
Accordingly, an object of the present invention is to suppress high-frequency noise without increasing the duty of the common mode core provided in the positive and negative conductor portions even when the capacity of the battery is increased.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, a high-frequency noise suppression device for an uninterruptible power supply according to the present invention is:
A power converter that supplies power converted to a load connected to a power source is stored in a power converter panel, and a battery that supplies power instead of the power source is stored in a battery panel to constitute an uninterruptible power supply. A first common mode core is inserted into a positive / negative main circuit conductor connecting between the power converter board and the battery board, and the ground terminal between the power converter board and the battery board is connected to the ground. The connection is made with a grounded connecting wire, and a second common mode core is inserted into the connecting wire and the positive and negative main circuit conductors.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a main circuit connection diagram showing an embodiment of the present invention. The difference from the conventional circuit described in FIG. 2 is that a second common mode core 20 is added and a ground wiring to the ground is provided. 21 is provided on the ground terminal 12, and the rest is the same as the conventional circuit of FIG. Therefore, the description of the same part is omitted.
As described above, since the battery 7 having a large capacity has a large capacitance to stray to the ground, the ground current resulting from this flows through the crossover 18 and is discharged to the ground through the ground wiring 21. Since the second common mode core 20 is configured to penetrate the connecting wire 18 together with the positive and negative conductors 8 described above, common mode noise superimposed on the positive and negative conductors 8 together with the ground current is also suppressed. Can do. Therefore, since the duty of the first common mode core 10 is reduced accordingly, it is possible to prevent the first common mode core 10 from being enlarged even when the capacity of the battery 7 is increased.
[0010]
The second common mode core 20 is shown in a state of being housed in the power converter board 2, but can be installed in the middle part between the power converter board 2 and the battery board 6 in the same manner as the first common mode core 10. Of course.
[0011]
【The invention's effect】
When the battery constituting the uninterruptible power supply is increased in capacity, when this battery is separated from the power converter and stored in a separate panel, common mode noise is generated on the positive and negative conductors connecting the battery and power converter. Superimpose. Therefore, in order to suppress this common mode noise, the positive and negative conductors are passed through the first common mode core. However, as the capacity of the battery increases, the size of the first common mode core must be further increased. Inconvenience disappears. On the other hand, in the present invention, a second common mode core is separately installed, and the connecting wire connecting the power converter board and the ground circuit of the battery board and the above-described positive and negative conductors are collectively penetrated. By installing the second common mode core, the duty of the first common mode core is reduced, and an effect of avoiding an increase in size can be obtained.
[Brief description of the drawings]
FIG. 1 is a main circuit connection diagram showing an embodiment of the present invention. FIG. 2 is a main circuit showing a conventional example for suppressing common mode noise of an uninterruptible power supply having a configuration separated into a power converter panel and a battery panel. Configuration diagram [Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Commercial power supply 2 Power converter board 3 Converter 4 Inverter 5 Load 6 Battery board 7 Battery 8 Positive / negative conductor 10 1st common mode cores 12 and 16 Grounding terminals 17 and 21 Grounding wiring 18 Crossover wire 20 2nd common mode core

Claims (2)

A power converter that supplies power converted to a load connected to a power source is stored in a power converter panel, and a battery that supplies power instead of the power source is stored in a battery panel to constitute an uninterruptible power supply.
A first common mode core is inserted into a positive and negative main circuit conductor connecting the power converter board and the battery board;
Between the ground terminal of the power converter panel and the ground terminal of the battery panel, connected by a jumper grounded to the ground,
A high-frequency noise suppression device for an uninterruptible power supply, wherein a second common mode core is inserted into the connecting wire and the positive and negative main circuit conductors. In the high frequency noise suppression device of the uninterruptible power supply device according to claim 1,
The high frequency noise suppression device for an uninterruptible power supply, wherein the second common mode core is housed in the power converter panel.

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