JPH0645162A - Noise Restaurant - Google Patents

Abstract

(57) [Abstract] [Purpose] In a noise restaurant such as an outer iron type, by forming the coil in a donut shape, it is possible to properly and easily form an electrostatic shield on the entire inner and outer peripheral surfaces of the coil. It is intended to reduce the size and weight, improve workability, and reduce the cost while keeping the performance comparable, and thus to easily obtain the three-phase type. [Structure] An input coil 1 and an output coil 2 in which a core 4 is inserted in an intermediate portion are formed individually and in a donut shape, respectively, and thus, these donut shapes in a state where the core 4 is not inserted. The input coil 1 and the output coil 2 are each provided with an electrostatic shield 3 made of a conductive material that is electromagnetically oriented in the same direction as the core 4 to be inserted in the intermediate portion on the inner and outer peripheral surfaces thereof. The coil 2 is separately and independently attached to the core 4 to achieve the intended purpose.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a noise restaurant used as a power source for various semiconductor devices.

[0002]

2. Description of the Related Art Since various semiconductor devices and the like dislike noise coming in from power supply lines, external devices and the like as much as possible, noise transformers for cutting off noise are used in transformers used for power supplies. The mainstream of conventional noise restaurants is an outer iron type, for a single phase, and the whole is wrapped with an iron cover or the outside of the coil is covered with an iron cover. A case where the outside of the coil is covered with an iron cover is illustrated, for example, as shown in FIG. 11, in which the input coil 11 and the output coil 12 are separately mounted on the core 14, and these coils are
A pair of iron covers 13 and 13 (usually made by die casting or casting) are covered from the left and right, and shield plates 15 and 15 are integrally provided at the inner middle portions of both iron covers, so that the input coil 11 and the output coil 12 are integrated. Between the input and output coils 11 and 12 to electrically block the noise from the power supply line and external equipment. This prevents radiation noise from being generated. However, in such a configuration, there are disadvantages that the space factor of the iron covers 13 and 13 becomes high, the outer shape becomes extremely large, the iron amount increases, the weight increases, and the cost also increases. there were. Also, because such an iron cover is required,
It is difficult to construct a noise restaurant for three phases, and therefore, in reality, three three-phase noise restaurants are used.

[0003]

If a metal foil tape is wound around the inner and outer peripheral surfaces of each coil to form an electrostatic shield, the same electrical performance can be expected and the iron cover can be eliminated. It is considered possible. But,
Generally, the input coil and the output coil of this type of transformer are of a rectangular shape, and in particular, in each corner portion, as shown in FIG.
As shown in, the inner corner is one point B, while the outer corner is an arc A of a quarter of a circle of radius r, so the ratio is infinite, and the metal foil tape 16 is attached to the coil. When wound, as shown in FIG. 12, in the above-mentioned B portion of the inner corner, it overlaps and becomes overcrowded, and since the insulating film 17 is applied to the inner side, the inner corner swells and is hard to fit into the core 14. Become. Further, it is necessary to make the bobbin larger, and the outer shape becomes larger accordingly. On the contrary, in the above-mentioned A portion of the outer corner, the portion becomes rough, wrinkles are more generated, and a gap is generated, so that radiation noise is easily generated. In addition, the winding of the metal foil tape is not easy, and the workability is greatly deteriorated. Therefore, it is almost impossible to put it to practical use as it is, and it is in the present situation that it has not been implemented. Therefore, in the present invention, in a noise restaurant such as an outer iron type, by forming the coil in a donut shape, an electrostatic shield can be properly and easily formed on the entire inner and outer peripheral surfaces of the coil, and the performance is comparable. It is intended to reduce the size and weight, improve the workability, reduce the cost, etc. in the absence state, and thus to easily obtain the three-phase one.

[0004]

To achieve the above object, the invention of claim 1 forms an input coil for inserting a core in an intermediate portion and an output coil individually and in a donut shape. Is characterized in that the inner and outer peripheral surfaces of the donut-shaped coil are subjected to electrostatic shielding by a conductive material, and these coils are individually and independently attached to the core.

Further, in the invention of claim 2, an input coil for inserting a core in an intermediate portion and an output coil are individually provided, and
Each is formed in a donut shape, and the inner and outer peripheral surfaces of these donut-shaped coils are each provided with an electrostatic shield by a conductive material, and the outside is molded with a synthetic resin mixed with a powder of a magnetic material having good high frequency characteristics, These coils are individually and independently mounted on the cores, and a high frequency dedicated magnetic shield plate is interposed between the coils.

[0006]

With the above-mentioned structure, the first and second aspects are provided.
In the invention described above, the input coil and the output coil formed in a donut shape enable the electrostatic shield to be uniformly and appropriately attached to the entire inner and outer peripheral surfaces, and easily.
Since the electrostatic shield is in the same electromagnetic direction as the core,
It does not cause an induced short-circuit current, properly blocks the intrusion of noise from the power line, external equipment, etc., and prevents the generation of radiated noise, which makes it possible to eliminate the conventional iron cover, and its performance is comparable. Depending on the state, it is possible to reduce the size and weight, improve workability, reduce costs, etc., and realize a noise restaurant for three phases to achieve the intended purpose. Further, in the invention of claim 2, the mold for the synthetic resin mixed with the powder of the magnetic material having good high frequency characteristics and the magnetic shield for exclusive use of high frequency interposed between the coils are the poles which still pass through the electrostatic shield. Properly shields a small amount of normal mode high frequency noise to improve performance.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS "Embodiment of the Invention of Claim 1" FIGS. 1 and 2
Shows an example of the implementation of the outer-iron type single-phase noise restaurant according to the invention of claim 1. In the figure,
DESCRIPTION OF SYMBOLS 1 is an input coil, 2 is two output coils, 3 is an electrostatic shield by a metal foil tape mounted on the inner and outer peripheral surfaces of these coils, and 4 is an input coil 1 and an output coil 2, respectively. It is a combined core. The input coil 1 and the output coil 2 are formed in a toroidal shape having a required diameter, and an insulating film 5 is applied to the inner and outer peripheral surfaces of each of which the core is not inserted, and a tape of metal foil serving as the electrostatic shield 3 is applied. It is wound evenly, and the winding start and winding end are overlapped with the insulating film 5 interposed therebetween. The metal foil tape of the electrostatic shield 3 is mainly a copper foil tape. The core 4 is composed of a pair of left and right cut cores 41, 41 having a vertically-elongated front shape and a semicircular cross section with a flat outer peripheral surface, but abutted on each one side. Part
It has a circular cross-sectional shape suitable for the coils 1 and 2.

FIGS. 3 and 4 relate to a modification of the previous example. In the configuration of the previous example, the output coil 2 is stopped to one, and
The cut cores 41, 41 are formed by combining a plurality of plate-shaped cut core pieces 411, 411 having different widths. 6 in the figure
Is an exterior material, 7 is a band, and 8 is a leg.

FIG. 5 shows an example of implementation of a noise restaurant for three phases according to the invention of claim 1. In this case, similarly to the previous example, the doughnut-shaped input coil 1 and the output coil 2 provided with the electrostatic shield 3 are applied to the respective phases, one for each phase, and three for convenience, and are respectively fitted to the EI type cores 4.

FIG. 6 relates to a modification of the three-phase noise restaurant of FIG. 5, and in the configuration of FIG. 5, the core 4 is cut into a plurality of plate-shaped cuts having different widths as in the case of FIGS. 3 and 4. It is formed by three cut cores 41, 41, 41 inside and outside formed by combining core pieces 411, 411. Also in this case, 6 is an exterior material, 7 is a band, and 8 is a leg.

[Embodiment of the Invention of Claim 2] FIGS. 7 and 8
Shows an example of implementation according to the invention of claim 2. In this case, in the above-mentioned ones shown in FIGS. 3 and 4, ferrite or the like having good high frequency characteristics is provided outside the toroidal input coil 1 and the output coil 2 each having an electrostatic shield 3 made of a conductive material on the inner and outer peripheral surfaces thereof. The mold 9 is made of a synthetic resin mixed with the powder of the ferromagnetic material, and a high-frequency magnetic shield plate 10 made of a plate of a ferromagnetic material such as ferrite is interposed between the coils. In this case, as shown in FIG. 8, the high-frequency magnetic shield plate 10 is formed into a rectangular shape which is equal to or slightly larger than the input coil 1 and the output coil 2 and has a through hole 101 formed in the center thereof to match the cross-sectional shape of the core 4. And is fitted into the core 4. In the case of FIG. 8,
Although the through hole 101 has a stepped shape in accordance with the cross-sectional shape of the core 4, it may have a circular shape as shown in FIG. Further, the outer circumference thereof may be circular as shown in FIG.
The shape is other appropriate.

"Comparison Test with Conventional Product" The single-phase noise restaurants shown in FIGS. 3 and 4 were subjected to a comparison test with a commercially available conventional product, and the results shown in the following table and FIGS. 14 to 25 were obtained. . [Comparative test sample] Type: Outer iron type single-phase noise restaurant Conventional product A: Entirely covered with an iron cover Conventional product B: Outer coil covered with an iron cover Capacity: 500VA

1) No load test, full load test, leakage current,
Distribution capacity, weight, volume

[Table 1] From the above results, the prototypes of the present invention are the conventional product A and the conventional product B.
It was found that the excitation current, the iron loss, the weight, and the volume were about half or less, and the others were about the same.

2) Various noise tests (input) common mode noise, (output) common mode noise With the connection shown in FIG. 14, a pulse with a pulse width of 400 ns and a rising edge of 1 ns is input from the noise simulator to the input side. The noise input voltage indicates the peak voltage of the noise simulator output, and the output voltage indicates the peak voltage of the wideband synchroscope. The same applies hereinafter. The results are shown in FIG. 15 for the prototype of the present invention, FIG. 16 for the conventional product A, and FIG. 17 for the conventional product B, showing almost no difference. However, in general, what becomes a problem as noise is noise of 10 MHz or less in this common mode noise, and how to eliminate this is important.
Then, when noise in the region of 20 MHz or less was extracted from the output noise, the results of FIGS. 26 to 29 were obtained. FIG. 26
Is a prototype of the present invention, FIG. 27 is a prototype, and the vertical sensitivity is 5 times, FIG. 28 is the conventional product A, and FIG. 29 is the conventional product B.
Is. From this, it was found that the common mode noise of 20 MHz or less of the prototype of the present invention was 1/5 or less of that of the conventional product A and the conventional product B. (Input) common mode noise, (output) normal mode noise With the connection shown in Fig. 18, a DC resistance of 50Ω is connected to the output side as the load resistance RL, and a pulse width of 400ns and a rising edge of 1ns from the noise simulator to the input side. Input the pulse of. The results are shown in Fig. 19 for the prototype of the present invention and Fig. 2 for the conventional product A.
0, the conventional product B is as shown in FIG. 21, and it is found that there is almost no difference. (Input) normal mode noise, (output) normal mode noise With the connection shown in Fig. 22, connect a DC resistance of 50Ω as the load resistance RL to the output side, and from the noise simulator to the input side, pulse width 400ns, rising 1ns. Input the pulse of. The results are shown in Fig. 23 for the prototype of the present invention and Fig. 2 for the conventional product A.
4. The conventional product B is as shown in FIG. 25, and it has been found that the prototype of the present invention is comparable to the prototype. Although different waveforms are seen in the conventional product A and the conventional product B, as described above,
It is thought that this is due to differences such as the use of iron covers. From the above, the prototype of the present invention has less exciting current and iron loss than the conventional product A and the conventional product B, is excellent in common mode noise elimination performance in a practical range, and has no other performance in comparison. It is obvious that the weight and the volume can be reduced to about half or less, and this leads to the cost being reduced to about half or less.

[0015]

According to the inventions of claim 1 and claim 2,
In a noise restaurant such as an outer iron type, since the inner and outer circumferential surfaces of the doughnut-shaped input coil and output coil are provided with an electrostatic shield by a conductive material, the input coil 1 or the output coil 2 can be connected to a power line, an external device, or the like. It is possible to accurately block the intrusion of noise and prevent the generation of radiated noise from itself, and the noise removal performance is not inferior, rather, it is the most important frequency band for practical use, namely 10MHz.
The common mode noise removal performance in the following areas can be made more excellent, and the conventional iron cover can be eliminated. Therefore, it is possible to reduce the external shape, weight and cost to about half or less of the conventional one, and it is possible to achieve a significant reduction in size and weight, which can not be expected from conventional products, and cost reduction. Therefore, it can be made inexpensive. As a result, the magnetizing current and iron loss can be reduced by the remarkable reduction in size and weight, and the performance can be further improved. Further, a noise restaurant for three phases, which could not be achieved conventionally, can be easily manufactured in the same manner. Further, since the electrostatic shield of each coil is electromagnetically oriented in the same direction as the core to be inserted in the intermediate portion, it does not intersect with the magnetic flux generated in the core, and therefore, the electrostatic shield has an induced short-circuit current. It never happens. Thus, the electrostatic shield may be obtained by winding a metal foil tape around the inner and outer circumferential surfaces of the doughnut-shaped input coil and output coil. In this winding, each coil is donut-shaped,
There is no inconvenience of winding a metal foil tape around a conventional rectangular coil. Therefore, the electrostatic shielding by winding the metal foil tape, which could not be practically achieved by the conventional rectangular coil, can be performed without any trouble, and mechanically, easily, easily, and accurately. You can wrap it with good quality. In addition, according to the invention of claim 2, a synthetic resin mold in which powder of a magnetic material having good high frequency characteristics is mixed is formed on the outside of each donut-shaped coil having an electrostatic shield made of a conductive material, and each coil is formed. Since a magnetic shield plate dedicated to high frequency is interposed between the coils, it is possible to properly shield even the slightest normal mode high frequency noise that does not pass even with the electrostatic shield, and further improve the performance. You can Therefore, it is possible to provide an epoch-making noise restaurant which has not existed in the past.

[Brief description of drawings]

FIG. 1 is a sectional front view showing an example of implementation of a single-phase noise restaurant according to the invention of claim 1.

FIG. 2 is a cutaway plan view of the same example.

FIG. 3 is a perspective view showing another embodiment of the single-phase noise restaurant according to the invention of claim 1.

FIG. 4 is a cutaway plan view of a main part of the example.

FIG. 5 is a front view showing an example of implementation of a three-phase noise restaurant according to the invention of claim 1.

FIG. 6 is a perspective view showing another embodiment of the three-phase noise restaurant according to the invention of claim 1;

FIG. 7 is a perspective view showing an example of implementation of a single-phase noise restaurant according to the invention of claim 2;

FIG. 8 is a cutaway plan view of a main part of the same example.

FIG. 9 is a plan view showing a modified example of the main part member of the example.

FIG. 10 is a plan view showing another modification of the main part member of the example.

FIG. 11 is a cutaway front view showing an example of a conventional noise restaurant.

FIG. 12 is a cutaway plan view showing an example of preceding thinking.

FIG. 13 is an explanatory diagram of a main part of the same example.

FIG. 14 is a circuit configuration diagram of a comparative test 1) regarding noise.

FIG. 15 is a graph showing the test results of the prototype of the present invention according to the same test 1).

FIG. 16 is a graph showing the test results of conventional product A according to the same test 1).

FIG. 17 is a graph showing the test results of conventional product B according to the same test 1).

FIG. 18 is a circuit configuration diagram of a noise comparison test 2).

FIG. 19 is a graph showing the test results of the prototype of the present invention according to the same test 2).

FIG. 20 is a graph showing the test results of conventional product A according to the same test 2).

FIG. 21 is a graph showing the test results of conventional product B according to the same test 2).

FIG. 22 is a circuit configuration diagram of a comparative test 3) regarding noise.

FIG. 23 is a graph showing the test results of the prototype of the present invention according to the same test 3).

FIG. 24 is a graph showing the test results of conventional product A according to the same test 3).

FIG. 25 is a graph showing the test results of conventional product B according to the same test 3).

FIG. 26 is a graph showing the test results of the prototype of the present invention when the output noise of 20 MHz or less according to the above test 1) is extracted.

FIG. 27 is a graph showing the test results of the prototype of the present invention when the output noise of 20 MHz or less according to the same test 1) was extracted at a vertical sensitivity of 5 times.

FIG. 28 is a graph showing the test results of the conventional product A when the output noise of 20 MHz or less according to the same test 1) was extracted.

FIG. 29 is a graph showing the test results of the conventional product B when the output noise of 20 MHz or less according to the same test 1) was extracted.

[Explanation of symbols]

 1 Input Coil 2 Output Coil 3 Electrostatic Shield 4 Core 5 Insulating Film 6 Exterior Material 7 Band 8 Leg 9 Mold 10 High Frequency Magnetic Shielding Plate 41 Cut Core 101 Through Hole 411 Plate Cut Core Piece

Claims (2)

[Claims] 1. An input coil and an output coil in which a core is inserted in an intermediate portion are formed individually and in a donut shape, and an electrostatic shield made of a conductive material is formed on the entire inner and outer peripheral surfaces of the donut coil. The noise restaurants are characterized in that these coils are individually and independently attached to the core. 2. An input coil and an output coil in which a core is inserted in an intermediate portion are formed individually and in a donut shape, and an electrostatic shield made of a conductive material is provided on the entire inner and outer peripheral surfaces of the donut coil. In addition, the outer surface of the coil is molded with a synthetic resin mixed with powder of magnetic material with good high-frequency characteristics, and these coils are individually mounted on the cores, and a high-frequency magnetic shield plate is placed between each coil. Noise restaurants characterized by being intervened.