JPH09232165A - Reactor and power converter using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable the use of the title reactor for a large high-frequency power by a construction wherein a core divided by a plurality of gaps for making a magnetic path have a magnetic reluctance is provided in a solenoid coil and a cooling liquid is made to flow through a cooling piping provided in parallel with the magnetic path of the core, while a packing material being excellent in heat conductivity is packed between the cooling piping and the core. SOLUTION: A coil 1 wound in the shape of a circle forms a cylindrical solenoid and a magnetic flux is generated inside by a current flowing therethrough. In a leg core 2 for forming a magnetic path of this magnetic flux, small gaps for making the magnetic path have a magnetic reluctance are disposed dispersedly. In order to prevent heating of the leg core 2, a rectangular hollow cooling piping 3 is provided in parallel with the magnetic path so that two sides thereof are in close contact with four corner parts of the outer periphery of the leg core 2. Between the cooling piping 3 and the leg core 2, a packing material 4 being excellent in heat conductivity is packed. According to this constitution, a reactor which can be used for a large high-frequency power and which is small in size and causes no problem of induction heating in the periphery is obtained and a power converter can be made small in size.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power conversion device to which a switch element such as a gate turn-off thyristor is applied, and relates to a high frequency operation reactor used for the power conversion device.

[0002]

2. Description of the Related Art Conventionally, an air-core reactor has been generally used as a reactor operated at high power and high frequency.

[0003]

In the above-mentioned prior art, when used with a large electric power, there is a problem that the surrounding structure is inductively heated by the leakage magnetic flux. There was a problem of increasing the size.

When a reactor having an iron core is adopted in order to solve the problem caused by induction heating, the leg iron core is divided and sandwiched between gap materials having poor heat conductivity, so that it is difficult to cool. Then, there was a problem that the iron core of the leg was overheated due to iron loss due to high frequency.

An object of the present invention is to provide a small-sized reactor used for high-frequency and high-power, which does not cause a problem of induction heating in surrounding structures.

Another object of the present invention is to provide a power converter using a high frequency reactor which is compact and does not cause a heating problem.

[0007]

The features of the present invention for attaining the above object are that a solenoid coil and a magnetic path of a magnetic flux generated inside the solenoid coil are arranged to form a magnetic path in the magnetic path. An iron core divided by a plurality of gaps to provide resistance, a hollow conductor provided in parallel with the magnetic path of the iron core, inside the cooling pipe, flowing cooling liquid, the cooling pipe and the iron core. And a filling material having a good thermal conductivity.

Also, in a preferred embodiment of the present invention, a plurality of iron core blocks made by laminating a plurality of silicon steel plates having the same width and having a thickness of about 0.3 mm or less are combined to form a substantially circular outer periphery. And a rectangular cooling pipe is arranged in parallel with the magnetic path so that the two surfaces are in close contact with the corners of the outer circumference of the leg iron core formed by combining the iron core blocks.

Another feature of the present invention is a power converter using the reactor in a circuit for passing a current of a high frequency component of about 200 hertz or more.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

FIG. 3 is a schematic view showing the positional relationship between the reactor coil, the iron core and the gap. In this example, a magnetic path is formed by connecting two coils and the upper and lower sides of a leg iron core with yoke iron cores, and the two leg iron cores each have a plurality of gaps formed by insulating plates distributed.

FIG. 1 is a cross-sectional view of the reactor of the present invention, showing a cross-section viewed from above the leg core on one side of FIG. The coil 1 wound in a circle forms a cylindrical solenoid,
The current flowing through this creates a magnetic flux inside. This magnetic flux can be generated in a direction penetrating the paper surface of FIG. 1, but the iron core 2 is arranged to form the magnetic path of the magnetic flux. This iron core is usually made by combining blocks formed by laminating a plurality of silicon steel plates having a uniform width and having a thickness of about 0.3 mm or less with different widths. In this embodiment, a through hole 10 through which a tightening bolt is inserted is provided at the center, and the outer periphery is assembled so as to have a substantially circular shape. This iron core is generally called a leg iron core.

Regarding the gap for giving a magnetic resistance to the magnetic path, in order to reduce the leakage magnetic flux in the gap portion, the gaps as small as possible are dispersedly arranged in the leg core. For this reason,
The leg iron core sandwiched between the gaps is in a thermally insulated state, and the leg iron core may overheat even if the loss generated in the leg iron core is relatively small. FIG. 2 is an enlarged view of four corner portions (inside the circle drawn by the one-dot chain line in FIG. 1) on the outer periphery of a leg iron core formed by combining iron core blocks. In this embodiment, in order to prevent heating, the rectangular hollow cooling pipe 3 is passed in parallel with the magnetic path so that the two surfaces closely contact the four corners of the outer circumference of the leg iron core. 2 of the cooling pipe here
Although the surface and the surface of the leg iron core are placed in close contact with each other, direct contact causes incomplete contact due to the distortion of the pipe and the step of the leg iron core. The thermally conductive filler 4 is filled. Here, a sheet of heat conductive silicon rubber (for example, sircon) is used as the filler, and the number of gap adjusting sheets is adjusted as necessary to enhance thermal contact. If the clay-like filler before forming into a sheet is filled and the cooling pipes are brought into close contact with each other, the thermal contact becomes higher. The cooling pipe 3 is held by the supporting member 5, and the outer periphery including the supporting member 5 is wound with the glass tape 6, the glass binding tape 7, and the insulating paper 8 to tightly fix the cooling pipe 3 to the leg core 2. By arranging the cooling pipe 3 in parallel with the magnetic path, it is possible to minimize the eddy current due to the leakage magnetic flux, so that it is possible to use a metal material having good thermal conductivity (eg, a rectangular hollow copper pipe) as the cooling pipe. Become. In order to prevent the cooling pipe and the leg iron core from electrically contacting each other and circulating the induced current due to the leakage flux in the plurality of cooling pipes, a thin insulating tape 9 is wound around the cooling pipes to insulate them. There is.

According to this embodiment, it is possible to realize a reactor in which the leg iron core does not overheat during high-frequency operation with a frequency of several hundreds hertz or higher.

The structure of the iron core has been mainly described above.
FIG. 3 is a schematic diagram showing the positional relationship between the coil of the reactor, the iron core, and the gap. In this embodiment, the two coils and the upper and lower sides of the leg iron core are connected by a yoke iron core to form a closed magnetic path to prevent the influence of leakage magnetic flux to the outside of the reactor. On each of the two leg iron cores, an insulating plate gap is distributed at a plurality of locations. Here, if a hollow conductor having insulating paper wrapped around it is used as the coil and the coil is cooled by passing a cooling liquid through it like the leg core, the loss generated in the coil can be effectively cooled. For example, pure water or insulating oil is used as the cooling liquid.

According to this embodiment, it is possible to realize a small reactor which is less affected by the leakage magnetic flux to the outside.

In a power conversion device to which a semiconductor switch element such as a gate turn-off thyristor, which has been increased in capacity in recent years, is applied, since a switching operation is performed at a high frequency of about 200 to 300 hertz or more, the reactor used for this is an air core. In this case, there is a problem that the device becomes large due to the problem that the metal structural material cannot be arranged in the periphery thereof. However, if the above reactor is applied, a small reactor can be housed and the mounting density can be increased, so that the power conversion device can be downsized.

[0018]

According to the present invention, it is possible to realize a compact reactor which is used for high frequency and large electric power and which does not cause a problem of induction heating in the periphery, and to realize miniaturization of the power conversion device.

[Brief description of drawings]

FIG. 1 is a sectional view of a reactor showing an embodiment of the present invention.

FIG. 2 is an enlarged view of the inside of a circle drawn by the alternate long and short dash line in FIG.

FIG. 3 is a schematic diagram showing a positional relationship between a reactor coil, an iron core, and a gap.

[Explanation of symbols]

1 ... Coil, 2 ... Leg core, 3 ... Cooling pipe, 4 ... Filler,
5 ... Supporting material, 6 ... Glass tape, 7 ... Glass binding tape, 8 ... Insulating paper, 9 ... Insulating tape.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Sadao Sudo Inventor, 3-1, 1-1 Sachimachi, Hitachi City, Ibaraki Hitachi Ltd. Hitachi Works (72) Inventor Takeshi Onishi 40 Nishinorikyucho, Yamashina-ku, Kyoto Tokuden Co., Ltd. (72) Inventor Yukio Horie 40 Nishinokyumiyacho, Yamashina-ku, Kyoto Tokuden Co., Ltd.

Claims (3)

[Claims] 1. A solenoid coil, an iron core which is arranged to form a magnetic path of a magnetic flux generated inside the solenoid coil, and which is divided by a plurality of gaps so as to have a magnetic resistance in the magnetic path, Inside the hollow conductor provided parallel to the magnetic path of the iron core,
A reactor provided with a cooling pipe in which a cooling liquid is flowed, and a filling material filled between the cooling pipe and an iron core and having good thermal conductivity. 2. The reactor according to claim 1, wherein an outer circumference of the iron core is substantially circular by combining a plurality of iron core blocks formed by laminating a plurality of silicon steel plates having a thickness of about 0.3 mm or less and having the same width. A reactor in which rectangular cooling pipes are arranged parallel to the magnetic path so that the two surfaces are in close contact with the outer peripheral corners of the leg iron core formed by combining the iron core blocks. 3. A power conversion device comprising the reactor according to claim 1 or 2 used in a circuit for passing a current of a high frequency component of about 200 hertz or more.