JPH08182193A - Radiation noise reducing device for switching power source - Google Patents

Abstract

PURPOSE: To effectively reduce radiation noise by using one or a plurality of clamp filters by forming a power supply cable in a simple shape. CONSTITUTION: The power supply cable 2 of a switching power source 1 is wound at least in one loop state, and at least one or more clamp filters 3a, 3b, 3c are inserted to the power supply cable 22 of the power source 1 side including the winding part 21.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a switching power supply for supplying stabilized DC power by switching a large current at a high speed, and more particularly, it is generated by switching a large current at a high speed. The present invention relates to a radiation noise reduction device that efficiently reduces generated noise.

[0002]

2. Description of the Related Art Switching power supplies have higher power efficiency than the conventional mainstream series dropper power supplies and can be made smaller and lighter by increasing the switching frequency. It is becoming the mainstream of liquefied power sources. However, since the switching power supply switches a large current of, for example, 45 A at a high speed, noise generated during switching poses a problem.

As a method of reducing this switching noise, there are a method of suppressing it with a noise source and a method of suppressing it with an input / output portion of a switching power supply. Regarding the radiation noise generated at the input / output portion of the switching power supply, particularly the radiation noise radiated into the air using the power supply cable as an antenna, as shown in FIG.
A measure such as inserting a large number of clamp filters 62 (for example, 5 to 10 pieces) into 1 is taken.

[0004]

Therefore, since it is necessary to use a large number of clamp filters 62, the number of parts is increased and the cost is also high.
There is a problem that the wiring work of the power supply cable 61 from the switching power supply 63 to the load also becomes complicated. The present invention was devised to solve such a problem, and an object thereof is to ensure radiation noise by using one or several clamp filters by making the power supply cable into a simple shape. An object of the present invention is to provide a radiation noise reducing device for a switching power supply that can reduce the noise.

[0005]

In order to solve the above problems, a radiation noise reducing apparatus for a switching power supply according to claim 1 of the present invention winds a power supply cable of the switching power supply at least once in a loop. At least one clamp filter is inserted in the power supply cable on the switching power supply side including the wound portion. In the radiation noise reducing apparatus for a switching power supply according to claim 2 of the present invention, the power supply cable for the switching power supply is wound at least once in a loop, and a clamp filter is attached to the power supply cable at the wound portion. One or two are inserted. The radiation noise reduction device for a switching power supply according to claim 3 of the present invention is the radiation noise reduction device according to claim 2, wherein one clamp filter is inserted in the power supply cable before the winding portion. Is.

[0006]

The operation of the radiation noise reducing apparatus for the switching power supply according to the first aspect will be described. The power supply cable of the switching power supply is wound at least once in a loop, and at least one clamp filter is inserted into the power supply cable on the switching power supply side including the wound portion. That is, by winding the power supply cable in a loop, the magnetic field generated in this winding portion is reduced by the interaction between the adjacent cables. Then, by inserting one or more clamp filters into the power supply cable in this state, it becomes possible to further reduce the generation of the magnetic field.

The operation of the radiation noise reducing apparatus for the switching power supply according to the second aspect will be described. The power supply cable of the switching power supply is wound at least once in a loop, and one or two clamp filters are inserted into the power supply cable of this wound portion.

That is, one clamp filter is provided on the wound portion.
By inserting them individually, not only the magnetic field is reduced in the insertion portion of the clamp filter, but also a part of the magnetic field generated in the cable portion adjacent to the clamp filter is reduced by the clamp filter. Further, when two clamp filters are inserted in the wound portion, each clamp filter reduces the magnetic field in the same manner as described above, so that the interaction of both clamp filters reduces the magnetic field more effectively. It is a thing.

The operation of the radiation noise reducing apparatus for the switching power supply according to the third aspect will be described. Insert one or two clamp filters into the power supply cable of the winding part, and at the power supply cable before the winding part,
Insert one clamp filter. That is, by reducing the magnetic field to some extent on the front side of the wound portion, it becomes possible to more effectively perform the action of reducing the magnetic field at the wound portion.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a radiation noise reducing apparatus for a switching power supply according to the present invention. This radiation noise reducing device is realized by a combination of a shape of a power supply cable 2 for supplying the power of the switching power supply 1 to a load (not shown) and a clamp filter 3 inserted in the power supply cable 2. That is, the power supply cable 2 of the switching power supply 1 is wound in a loop, and at least one clamp filter 3 is inserted in the power supply cable 22 on the switching power supply 1 side including the winding portion 21. is there.

However, although the clamp filters 3a, 3b and 3c are inserted in three positions in the figure, the clamp filters may be inserted in at least one of these positions. Also, the cable terminals 11, 1 of the switching power supply 1
The length L of the power supply cable 22 from 2 to the winding portion 21 is made as short as possible so that radiation noise is not emitted from this portion as much as possible.

That is, by winding the power supply cable 2 in a loop, the magnetic field generated in the winding portion 21 is reduced by the interaction between the magnetic fields generated in the adjacent cables 21a and 21b. Then, in this state, one or more clamp filters 3 are inserted into the power supply cable 2 to further reduce the generation of the magnetic field.

Here, one cable 2 of the winding portion 21
When the clamp filter 3a is inserted only in 1a (corresponding to claim 2), the clamp filter 3a
The magnetic field generated from the cable 21a is not only reduced at the insertion portion of, but also a part of the magnetic field generated from the adjacent cable 21c is reduced by the clamp filter 3a, and the magnetic field reduction effect is enhanced. It will be. Also, both cables 21a, 21 of the wound portion 21
When the clamp filters 3a, 3b are inserted only in b (corresponding to claim 2), the respective clamp filters 3a, 3b reduce the magnetic field in the same manner as described above. The magnetic field is more effectively reduced by the interaction of 3b.

Also, with one or two clamp filters 3a, 3b inserted in the cable of the winding portion 21,
One clamp filter 3c may be inserted in the power supply cable 22 (corresponding to claim 3). In this case, since the magnetic field can be reduced to some extent by the clamp filter 3c on the front side of the winding portion 21, the winding portion 2
The effect of reducing the magnetic field in 1 can be more effectively performed.

The inventor of the present invention uses the power supply cable 22 in each of the above cases (that is, when the clamp filter 3a is inserted only in the cable 21a, when the clamp filters 3a and 3b are inserted only in the cables 21a and 21b). And the case where the clamp filters 3a, 3b, 3c are inserted in the cables 21a, 21b respectively), the strength of the generated magnetic field was measured, and as a result, the same reduction effect as that of the conventional structure shown in FIG. 2 was obtained. It was confirmed.

That is, by winding the power supply cable 2 of the switching power supply 1 in a loop shape in the vicinity of the switching power supply 1, it is only necessary to insert one or a few clamp filters (about three), and the clamp filter. It was confirmed that the effect of reducing unnecessary radiation equivalent to that of the conventional structure in which 5 to 10 of the above-mentioned were inserted can be obtained.

[0017]

According to the radiation noise reducing apparatus for a switching power supply of the present invention, the power supply cable for the switching power supply is wound at least once in a loop, and the power supply cable on the switching power supply side including this winding portion is used. By inserting 1 to 3 clamp filters, the effect of reducing unnecessary radiation equivalent to that of the conventional structure in which 5 to 10 clamp filters are inserted can be obtained. That is, since it is only necessary to insert one to three clamp filters, the number of parts can be reduced and the cost can be provided at low cost.
Further, by inserting one clamp filter into the power supply cable of the winding portion, not only the magnetic field is reduced at the insertion portion of the clamp filter, but also a part of the magnetic field generated at the cable portion adjacent to this clamp filter. Since this clamp filter also reduces the magnetic field, the magnetic field is significantly reduced at this winding portion. That is,
Unwanted radiation is surely reduced at the wound portion. Further, when two clamp filters are inserted in the wound portion, each clamp filter reduces the magnetic field in the same manner as described above, so that the interaction of both clamp filters reduces the magnetic field more effectively. It is a thing. That is, unnecessary radiation is reliably reduced at the wound portion. In addition, by inserting one or two clamp filters in the power supply cable of the winding part and inserting the clamp filter in the power supply cable before the winding part, the magnetic field is increased to some extent on the front side of the winding part. Can be reduced, so that the effect of reducing the magnetic field in the wound portion can be more effectively performed.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a radiation noise reduction device for a switching power supply according to the present invention.

FIG. 2 is a configuration diagram showing a conventional radiation noise reduction device for a switching power supply.

[Explanation of symbols]

 1 Switching power supply 2 (21a, 21b, 22) Power supply cable 3 (3a-3c) Clamp filter 21 Winding part

Claims (3)

[Claims] 1. A power supply cable for a switching power supply is wound at least once in a loop, and a power supply cable on the switching power supply side including this winding portion is provided.
A radiation noise reduction device for a switching power supply, wherein at least one clamp filter is inserted. 2. A switching device characterized in that a power supply cable of a switching power supply is wound at least once in a loop, and one or two clamp filters are inserted in the power supply cable of the wound portion. Radiation noise reduction device for power supply. 3. The power supply cable before the winding portion,
The radiation noise reducing device for a switching power supply according to claim 2, wherein one clamp filter is inserted.