CN111740585A - A kind of anti-electromagnetic interference flexible DC converter valve secondary board and manufacturing method - Google Patents

Abstract

A secondary board card of a flexible direct current converter valve for preventing electromagnetic interference and a manufacturing method thereof, and a full-bridge MMC module, wherein the secondary board card comprises an IGBT driving board card, a central control SCE board card and/or a power supply board card, and is vertically placed in a shielding shell designed by permalloy materials, and the size of the shielding shell is designed according to the size of the secondary board card; coating an amorphous shielding material layer with the thickness of about 200-300 mu m on the surface of the permalloy shielding shell for shielding low-frequency electromagnetic waves, wherein the amorphous shielding material layer is prepared by adding amorphous magnetic alloy powder, magnetic fibers and nickel powder into acrylic resin according to a certain proportion; the flexible direct current converter valve MMC full-bridge module is packaged by adopting a metal aluminum shell in an electromagnetic shielding mode, and the same amorphous shielding composite material with the thickness of 200-300 mu m is coated inside the aluminum shell, so that the electromagnetic interference influence of electromagnetic wave radiation of an external MMC module on a high-potential secondary board card is further weakened.

Description

A kind of anti-electromagnetic interference flexible DC converter valve secondary board and manufacturing method

technical field

The invention belongs to the technical field of high-voltage flexible direct current transmission, relates to a protection measure for the secondary equipment of a high-voltage flexible direct current transmission converter valve against electromagnetic interference radiation, and in particular relates to an electromagnetic interference-proof flexible direct current converter valve secondary board and the same. Manufacturing method, and full-bridge MMC module.

Background technique

UHV DC transmission technology has the advantages of low loss, long-distance large-capacity transmission, etc., flexible DC transmission is flexible and controllable, and can form multi-terminal networking and other advantages, which has become the future development trend of DC transmission. As the core equipment of the converter station, the flexible DC transmission converter valve is directly related to the safe operation of the power grid. Therefore, to improve the reliability of the flexible DC converter valve, it is necessary to ensure that the secondary system equipment of the converter valve is normal. run.

High-potential secondary boards such as IGBT driver boards, central control SCE boards, and power supply boards directly act on the high-potential flexible straight valve tower and are subjected to complex electromagnetic field environments; it must be able to ensure high-potential secondary boards The card can withstand strong electromagnetic environment and work reliably under complex electromagnetic conditions, thus ensuring the normal turn-on and turn-off of the IGBT.

Due to the lack of corresponding theoretical research, the high-potential secondary board design of traditional flexible DC converter valves directly exposes the secondary board without any shielding measures or is just a simple conductive outer shielding shell design, which cannot meet the requirements. To meet the reliability requirements in complex electromagnetic environments with voltage levels of 500kV or even higher, a new shielding scheme is designed, which can not only meet the requirements of electric field shielding, but also meet the requirements of electromagnetic shielding.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a flexible DC converter valve secondary board for preventing electromagnetic interference and a manufacturing method thereof, as well as a full-bridge MMC module, which adopts different materials and structural design methods to redesign electromagnetic shielding, and has strong electromagnetic protection performance. , in order to greatly improve the reliability of the IGBT operation, suitable for use as an electromagnetic suppression measure for the flexible DC converter valve.

To achieve the above object, the present invention adopts the following technical solutions:

A first aspect of the present invention provides an electromagnetic interference-proof flexible DC converter valve secondary board, wherein the secondary board includes an IGBT driver board, a central control SCE board and/or a power board;

The secondary board is covered with a shielding shell on the outside, the shielding shell is made of permalloy material, and the surface is coated with an amorphous shielding composite material layer with a thickness of 200-300 μm.

Further, the amorphous shielding composite material layer includes nickel powder, magnetic fiber, amorphous magnetic powder and acrylic resin, wherein the mass fraction ratio is nickel powder: magnetic fiber: amorphous magnetic powder: acrylic resin=1:0.5:1 :8～1:0.7:1:9.

Further, the permalloy includes an iron-nickel alloy and a cobalt-manganese alloy, wherein the iron-nickel alloy accounts for about 70%-80% by mass, and the cobalt-manganese alloy accounts for about 20%-30% by mass.

Further, a porous design is adopted on the surface of the shielding shell to dissipate heat.

Further, openings are provided at the corresponding positions of the shielding shell to facilitate the connection of the power cord and the optical fiber.

Further, the secondary plate is fixedly connected to the shielding shell through screws.

A second aspect of the present invention provides a manufacturing method of a flexible DC converter valve secondary board for preventing electromagnetic interference, comprising the following steps:

Nickel powder, magnetic fiber and amorphous magnetic powder with a particle size of 1-10 μm were selected, and the mass fraction ratio of the three was 1:0.5:1-1:0.7:1, and the surface was modified with a coupling agent to obtain Modified magnetic particles;

Dispersing the magnetic particles uniformly with ethanol or xylene dispersant;

Add ethyl acetate diluent, mix it into acrylic resin, and the mass ratio of ethyl acetate and acrylic resin is about 0.5:1 to obtain a mixed solution of amorphous shielding composite material;

uniformly coating the amorphous shielding composite material on the surface of the shielding shell made of permalloy material, and the coating thickness is 200 μm to 300 μm;

The shielding shell coated with the amorphous shielding composite material is heated and cured, the temperature is 150°C, and the curing time is 10h;

The cured shielding shell is fixedly connected to the outside of the secondary board.

A third aspect of the present invention provides a full-bridge MMC module of an electromagnetic interference-proof flexible DC converter valve, the full-bridge MMC module comprising the electromagnetic interference-proof flexible DC converter valve secondary board as described above.

Further, the MMC module is covered with an aluminum shielding case outside, and the inside of the aluminum shielding case is coated with an amorphous shielding material layer with a thickness of 200 μm˜300 μm.

Further, the outside of the aluminum shielding shell is coated with conductive paint.

In conclusion, the present invention provides an electromagnetic interference-proof flexible DC converter valve secondary board, a manufacturing method thereof, and a full-bridge MMC module. The secondary board includes an IGBT drive board, a central control SCE board and/or a power board; the secondary board is covered with a shielding shell, the shielding shell is made of permalloy material, and the surface is coated with a thickness of 200μm～ 300μm layer of amorphous shielding composite material. The material of the amorphous shielding layer is made of amorphous magnetic alloy powder, magnetic fiber and nickel powder added to acrylic resin in a certain proportion; outside the flexible DC converter valve MMC full bridge module, a metal aluminum shell electromagnetic shielding package is used, and The same kind of amorphous shielding composite material with a thickness of 200 μm to 300 μm is coated inside the aluminum shell to further weaken the electromagnetic interference effect of the electromagnetic wave radiation of the external MMC module on its high-potential secondary board.

The above-mentioned technical scheme of the present invention has the following beneficial technical effects:

Improve the operation reliability of the current flexible DC converter valve, and weaken the influence of the external strong electric field and the high-frequency electromagnetic field generated by the turn-on and turn-off of the IGBT on the operation of the secondary board through the design of the electromagnetic interference shielding scheme. The shielding scheme has a simple structure and is resistant to The electromagnetic interference ability is strong and the cost is low, which can improve the operation stability of the flexible DC converter valve.

Description of drawings

1 is a schematic structural diagram of a high-potential secondary board card for preventing electromagnetic interference according to an embodiment of the present invention;

2 is a schematic structural diagram of an outer aluminum shielding case of a full-bridge MMC module for preventing electromagnetic interference according to an embodiment of the present invention.

Reference signs: 1. Shielding shell; 2. Amorphous shielding material layer; 3. Secondary board; 4. Aluminum shielding shell; 5. Conductive paint.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the specific embodiments and the accompanying drawings. It should be understood that these descriptions are exemplary only and are not intended to limit the scope of the invention. Also, in the following description, descriptions of well-known structures and techniques are omitted to avoid unnecessarily obscuring the concepts of the present invention.

As shown in FIG. 1 , a first aspect of the present invention provides an electromagnetic interference-proof flexible DC converter valve secondary board, the secondary board includes an IGBT driver board, a central control SCE board and/or a power board Card; the secondary board is covered with a shielding shell 1, the shielding shell is made of permalloy material, and the surface is coated with an amorphous shielding composite material layer 2 with a thickness of 200 μm to 300 μm. Different from the traditional aluminum shielding shell scheme, the outer shielding shell made of permalloy material is used this time, and the nickel-based filler ratio is 75%. The permalloy made of this material is used as the IGBT high-potential secondary board. The shielding measures can greatly reduce the electromagnetic interference degree of the high-frequency electromagnetic field generated when the IGBT is turned on and off to the high-potential secondary board. The IGBT of the flexible DC converter valve full-bridge MMC module will generate high-frequency electromagnetic interference radiation when it is turned on and off. In addition, its normal operating frequency is about several hundred hertz. In order to suppress the low-frequency electromagnetic wave, the high-potential secondary For the radiation interference of the board, the surface of the outer shielding shell made of permalloy should be coated with a layer of amorphous shielding material of 200 μm to 300 μm, which can reflect and absorb low-frequency electromagnetic waves.

Further, the amorphous shielding composite material layer includes nickel powder, magnetic fiber, amorphous magnetic powder and acrylic resin, wherein the mass fraction ratio is nickel powder: magnetic fiber: amorphous magnetic powder: acrylic resin=1:0.5:1 :8～1:0.7:1:9. The preparation of the thin layer of the amorphous shielding composite material must be carried out in strict accordance with the preparation process. The particle size of nickel powder, magnetic fiber and amorphous magnetic powder is in the range of 1 to 10 μm. Strictly follow the recipe and finally pour into acrylic resin to make a modified composite. The dispersion of the prepared amorphous shielding composite coating particles should be uniform, and there should be no agglomeration. The modified composite material is uniformly coated on the surface of the shielding shell and cured at a certain temperature. The surface of the shielding shell after curing is shown in FIG. 1 .

Further, the permalloy includes iron-nickel composite material and cobalt-manganese alloy, wherein the mass of iron-nickel alloy material is 70%-80%, the mass of cobalt-manganese alloy is 20%-30%, and the main component of permalloy is It is mainly composed of iron-nickel composite materials. Cobalt-manganese alloy elements are added to the alloy to enhance its magnetic permeability, which can absorb and reflect electromagnetic waves.

Further, a porous design is adopted on the surface of the shielding shell to dissipate heat.

Further, openings are provided at the corresponding positions of the shielding shell to facilitate the connection of the power cord and the optical fiber.

Further, the secondary plate is fixedly connected to the shielding shell through screws, so as to ensure that the installation of the secondary plate is firm and reliable.

A second aspect of the present invention provides a manufacturing method of a flexible DC converter valve secondary board for preventing electromagnetic interference, comprising the following steps:

Nickel powder, magnetic fiber and amorphous magnetic powder with a particle size of 1-10 μm were selected, and the mass fraction ratio of the three was 1:0.5:1-1:0.7:1, and the surface was modified with a coupling agent. Specifically, the micropowder is first baked in an oven (200° C.) to evaporate the internal moisture and impurities adsorbed on the surface. Put it into the air to cool naturally, add ethanol to wash, wash off the residues on the surface of the particles, and finally put it into an oven to dry. Put the treated micropowder into a beaker containing an acetone solution, and at the same time add a coupling agent (3wt% of the micropowder filler) to modify the micropowder particles to obtain modified magnetic particles;

The magnetic particles are uniformly dispersed by using ethanol or xylene dispersant; specifically, the mass of the dispersant is 10 times that of the micropowder filler;

Add ethyl acetate diluent, mix it into acrylic resin, and the mass ratio of ethyl acetate and acrylic resin is about 0.5:1 to obtain a mixed solution of amorphous shielding composite material;

uniformly coating the amorphous shielding composite material on the surface of the shielding shell made of permalloy material, and the coating thickness is 200 μm to 300 μm;

The shielding shell coated with the amorphous shielding composite material is heated for vacuum curing, the temperature is 150°C, and the curing time is 10h;

The cured shielding shell is fixedly connected to the outside of the secondary board.

Three kinds of magnetic conductive fillers with particle size of 1-10 μm nickel powder, magnetic fiber and amorphous magnetic powder are selected. The surface of the particles must be modified in advance, and the modified three filler particles are uniformly dispersed with a dispersant. The linking agent is cross-linked, poured into acrylic resin, and finally an amorphous shielding composite material is obtained. The shielding shell coated with the amorphous shielding composite material is put into an oven with a certain temperature environment for curing, so as to ensure that the amorphous shielding composite material layer has good bonding performance on the outer layer of the shielding shell after curing and does not fall off.

A third aspect of the present invention provides a full-bridge MMC module of an electromagnetic interference-proof flexible DC converter valve. As shown in FIG. 2 , the full-bridge MMC module includes the electromagnetic interference-proof flexible DC converter as described above. Valve secondary board 3.

Further, the MMC module is covered with an aluminum shielding shell 4 outside, and the inside of the aluminum shielding shell is coated with an amorphous shielding material layer 2 with a thickness of 200 μm˜300 μm. The MMC full-bridge module includes IGBT primary equipment and secondary equipment, and adopts aluminum shielding shell design, as shown in Figure 2. Shield the external high electric field, and at the same time, coat a thin layer of amorphous shielding composite material with a thickness of 200 μm to 300 μm inside the aluminum shielding shell. It is internally reduced to reduce the electromagnetic radiation interference to adjacent sub-modules and other sub-modules. The shielding aluminum shell can be coated with good conductive paint for the purpose of beautiful craftsmanship and high electric field insulation protection.

Further, as shown in FIG. 2 , the outside of the aluminum shielding shell is coated with conductive paint 5 . On the periphery of the full-bridge MMC module, an aluminum shielding shell is used to shield the external high electric field, and a layer of amorphous shielding material with a thickness of 200 μm to 300 μm is coated inside the aluminum shielding shell. The exterior can be coated with a layer of conductive paint. The purpose of coating the inside of the aluminum shielding shell with an amorphous shielding material layer is to minimize and weaken the influence of the electromagnetic wave of the external module on the electromagnetic interference of the single module.

In summary, the present invention provides an electromagnetic interference-proof flexible DC converter valve secondary board and a manufacturing method thereof, as well as an electromagnetic interference-proof full-bridge MMC module including the secondary board. The secondary board includes an IGBT drive board, a central control SCE board and/or a power board; the secondary board is covered with a shielding shell, the shielding shell is made of permalloy material, and the surface is coated with a thickness of 200μm～ 300μm layer of amorphous shielding composite material. The material of the amorphous shielding layer is made of amorphous magnetic alloy powder, magnetic fiber and nickel powder added to acrylic resin in a certain proportion; outside the flexible DC converter valve MMC full bridge module, a metal aluminum shell electromagnetic shielding package is used, and The same kind of amorphous shielding composite material with a thickness of 200 μm to 300 μm is coated inside the aluminum shell to further weaken the electromagnetic interference effect of the electromagnetic wave radiation of the external MMC module on its high-potential secondary board.

The above technical solution of the present invention can improve the operation reliability of the current flexible DC converter valve, and the influence of the external strong electric field and the high-frequency electromagnetic field generated by the turn-on and turn-off of the IGBT on the operation of the secondary board can be weakened through the design of the electromagnetic interference shielding solution. The shielding scheme has the advantages of simple structure, strong anti-electromagnetic interference capability and low cost, and can improve the operation stability of the flexible DC converter valve.

The invention provides an electromagnetic interference prevention method for a high-potential secondary board for a flexible-DC converter valve module, which is particularly suitable for a flexible-DC converter valve under high-potential conditions, but is not limited to the application of the flexible-DC converter valve. It can also be used as the electromagnetic shield of the secondary board of the high-voltage DC circuit breaker.

It should be understood that the above-mentioned specific embodiments of the present invention are only used to illustrate or explain the principle of the present invention, but not to limit the present invention. Therefore, any modifications, equivalent replacements, improvements, etc. made without departing from the spirit and scope of the present invention should be included within the protection scope of the present invention. Furthermore, the appended claims of this invention are intended to cover all changes and modifications that fall within the scope and boundaries of the appended claims, or the equivalents of such scope and boundaries.

Claims (10)

1. a flexible DC converter valve secondary board for preventing electromagnetic interference, it is characterized in that, described secondary board comprises IGBT drive board, central control SCE board and/or power board; The secondary board is covered with a shielding shell on the outside, the shielding shell is made of permalloy material, and the surface is coated with an amorphous shielding composite material layer with a thickness of 200-300 μm. 2. The flexible DC converter valve secondary board for preventing electromagnetic interference according to claim 1, wherein the amorphous shielding composite material layer comprises nickel powder, magnetic fiber, amorphous magnetic powder and acrylic resin, wherein , the mass fraction ratio is nickel powder: magnetic fiber: amorphous magnetic powder: acrylic resin=1:0.5:1:8～1:0.7:1:9. 3. The flexible DC converter valve secondary board for preventing electromagnetic interference according to claim 1 or 2, wherein the permalloy comprises an iron-nickel composite material and a cobalt-manganese alloy, wherein the iron-nickel The mass fraction of the composite material is 70% to 80%, and the mass fraction of the cobalt-manganese alloy is 20% to 30%. 4 . The flexible DC converter valve secondary board for preventing electromagnetic interference according to claim 1 , wherein a porous design is adopted on the surface of the shielding shell to dissipate heat. 5 . 5 . The flexible DC converter valve secondary board for preventing electromagnetic interference according to claim 1 , wherein openings are provided at corresponding positions of the shielding shell to facilitate the connection of power lines and optical fibers. 6 . 6 . The flexible DC converter valve secondary board for preventing electromagnetic interference according to claim 1 , wherein the secondary board is fixedly connected to the shielding shell through screws. 7 . 7. A manufacturing method of a flexible DC converter valve secondary board for preventing electromagnetic interference, characterized in that it comprises the following steps: Nickel powder, magnetic fiber and amorphous magnetic powder with a particle size of 1-10 μm were selected, and the mass fraction ratio of the three was 1:0.5:1-1:0.7:1, and the surface was modified with a coupling agent to obtain Modified magnetic particles; Dispersing the magnetic particles uniformly with ethanol or xylene dispersant; Add ethyl acetate diluent, mix it into acrylic resin, and the mass ratio of ethyl acetate and acrylic resin is about 0.5:1 to obtain a mixed solution of amorphous shielding composite material; uniformly coating the amorphous shielding composite material on the surface of the shielding shell made of permalloy material, and the coating thickness is 200 μm to 300 μm; The shielding shell coated with the amorphous shielding composite material is heated for vacuum curing, the temperature is 150°C, and the curing time is 10h; The cured shielding shell is fixedly connected to the outside of the secondary board. 8. An electromagnetic interference-proof flexible DC converter valve full-bridge MMC module, characterized in that the full-bridge MMC module comprises the electromagnetic interference-proof flexible DC converter valve according to any one of claims 1-6 Secondary board. 9 . The flexible DC converter valve full-bridge MMC module for preventing electromagnetic interference according to claim 8 , wherein the MMC module is externally coated with an aluminum shielding shell, and the interior of the aluminum shielding shell is coated with a thickness of 200 μm～ 300μm layer of amorphous shielding material. 10 . The flexible DC converter valve full-bridge MMC module for preventing electromagnetic interference according to claim 9 , wherein the outside of the aluminum shielding shell is coated with conductive paint. 11 .

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