JP2017212324A - Current limiting coil for DC power supply - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an early rise of a current immediately after a large voltage is applied with the suppression of a current increase as a lapse of time.SOLUTION: A current limiting coil 1 is used in DC power supply under a normal temperature (which is not superconductive). The current limiting coil 1 has a coil 10 and a coil 20 which are differentially connected. The coil 10 and the coil 20 are wound around a core which was made of a material which can pass a magnetic flux. By the insertion of the current limiting coil 1 in the middle of a DC feeder line, an operation time such as a circuit breaker and a fuse can be reduced while preventing the sudden occurrence of an excessive current.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a DC current limiting coil used in DC power feeding (not superconducting) under normal temperature.

  A system for supplying high voltage direct current to a server in a data center or the like is known. In addition, research and development of high voltage direct current (HVDC) power transmission of about 380 V has been promoted aiming at application to smart grids.

  When a short circuit accident or the like occurs in such a high-voltage DC power supply line, an excessive current may flow. This excessive current can be suppressed by inserting a coil in the middle of the feeder line. When the voltage changes rapidly, the inductance of the coil suppresses the rapid change of current.

For example, the circuit breaker interrupts the current when an excessive current starts flowing and time elapses and the accumulated value of the current reaches a predetermined value.
However, when a short circuit accident or the like occurs and a large voltage is applied, the current value immediately after the occurrence of the short circuit accident or the like is small, and the current flowing through the coil (magnetic flux density) gradually increases with time. For this reason, it takes time until the accumulated value of the current reaches a value for operating the circuit breaker and the circuit breaker operates to interrupt the current.

  Further, the resistance of the coil winding is very small. When the resistance of the short-circuited portion is small, if the coil is magnetically saturated before the current is cut off, the inductance becomes very small, and a huge current may flow instantaneously.

  An object of the present invention is to provide a current-limiting coil for DC power feeding that can quickly increase the current immediately after a large voltage is applied and can suppress an increase in current as time elapses.

In order to achieve the above object, the current-limiting coil for DC power feeding of the present invention is:
A current-limiting coil for DC power supply used in DC power supply,
A core made of a material that allows easy passage of magnetic flux,
Two coils wound around the core and differentially connected;
It is characterized by providing.

Preferably, the DC current limiting coil of the present invention is
The core includes a first yoke and a second yoke facing each other, a first leg connecting one end of the first yoke and one end of the second yoke, and the first A second leg connecting the other end of the one yoke and the other end of the second yoke;
The two coils are wound around the first leg or the second leg,
It is characterized by that.

Preferably, the DC current limiting coil of the present invention is
The core includes a first yoke and a second yoke facing each other, a first leg connecting one end of the first yoke and one end of the second yoke, and the first A second leg connecting the other end of the one yoke and the other end of the second yoke;
One of the two coils is wound around the first leg,
Another one of the two coils is wound around the second leg,
It is characterized by that.

Preferably, the DC current limiting coil of the present invention is
The core includes a first yoke and a second yoke facing each other, a first leg connecting one end of the first yoke and one end of the second yoke, and the first A second leg connecting the other end of one yoke and the other end of the second yoke; a first extension yoke extending from the other end of the first yoke; A second extension yoke extending from the other end of the second yoke; an end of the first extension yoke opposite to the first yoke; and the second extension yoke. And a third leg portion having a gap in the middle thereof, and connecting the yoke and the opposite end portion,
One of the two coils is wound around the first leg,
Another one of the two coils is wound around the second leg,
It is characterized by that.

Preferably, the DC current limiting coil of the present invention is
The core includes a first yoke and a second yoke facing each other, a first leg connecting one end of the first yoke and one end of the second yoke, and the first A second leg connecting the other end of the one yoke and the other end of the second yoke, an intermediate portion of the first yoke and an intermediate portion of the second yoke; A third leg having a gap in the middle;
One of the two coils is wound around the first leg,
Another one of the two coils is wound around the second leg,
It is characterized by that.

  According to the present invention, the rise of current immediately after a large voltage is applied can be accelerated, and an increase in current can be suppressed as time passes.

It is a schematic diagram which shows an example of a structure of the current-limiting coil for DC power supply which concerns on embodiment of this invention. It is a figure which shows an example of the voltage applied to the DC current limiting coil of FIG. 1, and the electric current which flows there. It is a figure which shows an example of a structure of the specific magnetic circuit of the current-limiting coil for DC feeding of FIG. It is a figure which shows an example of the time passage of the electric current when the voltage E is applied to the magnetic circuit of FIG. It is a figure which shows an example of a structure of the current-limiting coil by which two coils were wound on the left leg part of the rectangular core. It is a figure which shows an example of a structure of the current limiting coil by which two coils were each wound by the left leg part and right leg part of a rectangular core. It is a figure which shows an example of a structure of the current limiting coil which has the core to which the path | route of the leakage magnetic flux was added adjacent to the rectangular part. It is a figure which shows an example of a structure of the current limiting coil which has the core by which the path | route of the leakage magnetic flux was added in the middle of the rectangular part.

  DESCRIPTION OF EMBODIMENTS Hereinafter, a DC power supply current limiting coil according to an embodiment of the present invention will be described in detail with reference to the drawings. In all the drawings for explaining the embodiments, common constituent elements are denoted by the same reference numerals, and repeated explanation is omitted.

FIG. 1 shows an example of the configuration of a DC current limiting coil 1 according to an embodiment of the present invention. FIG. 3 shows an example of a specific magnetic circuit configuration of the DC current limiting coil 1 of FIG.
The current limiting coil 1 includes a coil 10, a coil 20, and a core 30.
The coil 10 and the coil 20 are differentially connected in series between the terminal T1 and the terminal T2. When the self-inductances of the coil 10 and the coil 20 are L1 and L2, respectively, and the mutual inductance is M, the combined inductance of the current limiting coil 1 is L1 + L2-2M.
The coil 10 and the coil 20 are wound around the core 30. When the number of windings of the coil 10 and the coil 20 is the same, L1 = L2.
The core 30 is made of a material that can easily pass magnetic flux such as iron. However, the core 30 may be made of a material other than iron as long as it is a material that allows easy passage of magnetic flux.

The current limiting coil 1 is inserted in the middle of the DC power supply line. For example, as shown in FIG. 2, when a voltage E is applied with the terminal T1 and the terminal T2 as the positive side and the negative side, respectively, as shown in FIG. 2, the coil 10 and the coil 20 are directed from the terminal T1 toward the terminal T2. Current i flows.
At this time, as shown in FIG. 3, a magnetic flux Φ _M1 due to the coil 10 and a magnetic flux Φ _M2 due to the coil 20 are generated inside the core 30 by the current i. The voltage E1 and the voltage E2 respectively to the coil 10 and the coil 20 is caused by the magnetic flux [Phi _M1 and the magnetic flux [Phi _M2. E = E1 + E2. Since the coil 10 and the coil 20 are differentially connected, the magnetic flux Φ _M1 and the magnetic flux Φ _M2 cancel each other. For this reason, the mutual inductance 2M is subtracted from the self-inductances L1 and L2 of the coils 10 and 20, and the combined inductance of the current limiting coil 1 becomes small.
As shown in FIG. 4, immediately after the voltage E is applied, the current i increases with a slope of E / (L1 + L2-2M). Thus, the rise of the current i is fast.

As shown in FIG. 3, when the current i flows, a leakage flux Φ _L1 from the coil 10 and a leakage flux Φ _L2 from the coil 20 are generated. Leakage magnetic flux Φ _L1 and leakage magnetic flux Φ _L2 pass through, for example, air. A leakage inductance corresponding to each of the leakage flux Φ _L1 and the leakage flux Φ _L2 is generated. As time elapses, the current i increases, and the leakage flux Φ _L1 and the leakage flux Φ _L2 increase. As a result, the state of the magnetic flux in the magnetic circuit changes, and as shown in FIG. 4, the increase rate of the current i decreases and the increase of the current i is suppressed.

As will be described below, the current-limiting coil 1 can change the state of the magnetic flux in the magnetic circuit by changing the shape of the core 30 and how the coils 10 and 20 are wound.
FIG. 5 shows an example of the configuration of a current-limiting coil 1A in which two coils 10A and 20A are wound on the left leg P1 of the rectangular core 30A.
Current limiting coil 1A includes a coil 10A, a coil 20A, and a core 30A.
The core 30A includes a yoke Y1, a yoke Y2, a leg part P1, and a leg part P2. The yoke Y1 and the yoke Y2 face each other. The leg P1 connects the left end of the yoke Y1 and the left end of the yoke Y2. The leg P2 connects the right end of the yoke Y1 and the right end of the yoke Y2.
The windings of the coil 10A and the coil 20A are wound around the leg P1 in the same direction (for example, clockwise). Terminals T1 and T2 are respectively provided at one end of the coil 10A and one end of the coil 20A (the beginning of winding of the coil 10A and the beginning of winding of the coil 20A) disposed on the yoke Y1 side. The other end of coil 10A and the other end of coil 20A (the end of winding of coil 10A and the end of winding of coil 20A) are connected.
In the current limiting coil 1A, the coupling coefficient between the coil 10 and the coil 20 is close to 1, and the leakage flux Φ _L1 and the leakage flux Φ _L2 are small.
The windings of the coil 10A and the coil 20A may be wound in the same direction around the leg part P2 instead of the leg part P1.

FIG. 6 shows an example of the configuration of a current-limiting coil 1B in which two coils 10B and 20B are wound around a left leg P1 and a right leg P2 of a rectangular core 30A.
The current limiting coil 1B includes a coil 10B, a coil 20B, and a core 30A.
The core 30A of the current limiting coil 1B is the same as that of the current limiting coil 1A.
The winding of the coil 10B is wound clockwise around the leg P1. The winding of the coil 20B is wound around the leg P2 counterclockwise. A terminal T1 and a terminal T2 are provided at the end of the coil 10B on the yoke Y1 side and the end of the coil 20B on the yoke Y1 side (the beginning of winding of the coil 10B and the beginning of winding of the coil 20B), respectively. The end of the coil 10B on the yoke Y2 side and the end of the coil 20B on the yoke Y2 side (the end of winding of the coil 10B and the end of winding of the coil 20B) are connected.
In the current limiting coil 1B, the coupling coefficient between the coil 10B and the coil 20B is smaller than that of the current limiting coil 1A, and the leakage flux Φ _L1 and the leakage flux Φ _L2 are larger than those of the current limiting coil 1A.

FIG. 7 shows an example of the configuration of a current limiting coil 1 </ b> C having a core 30 </ b> B to which a leakage magnetic flux path is added adjacent to a rectangular portion.
The current limiting coil 1C includes a coil 10B, a coil 20B, and a core 30B.
The core 30B includes a yoke Y1, a yoke Y2, an extension yoke Y3, an extension yoke Y4, a leg part P1, a leg part P2, and a leg part P3. The yoke Y1 and the yoke Y2 face each other. The extension yoke Y3 is obtained by extending the yoke Y1. The extension yoke Y4 is obtained by extending the yoke Y2. The leg P1 connects the left end of the yoke Y1 and the left end of the yoke Y2. The leg P2 connects the right end of the yoke Y1 and the right end of the yoke Y2, that is, the connecting portion between the yoke Y1 and the extension yoke Y3 and the connecting portion between the yoke Y2 and the extension yoke Y4. The leg portion P3 includes the right end portion of the extension yoke Y3 and the right end portion of the extension yoke Y4 (the end portion on the opposite side of the extension yoke Y3 from the yoke Y1 and the end portion on the extension yoke Y4 opposite to the yoke Y2). Link. However, the leg part P3 has a gap (gap) AG1 in the middle.

The coil 10B and the coil 20B in the current limiting coil 1C are the same as those of the current limiting coil 1B. That is, the winding of the coil 10B is wound clockwise around the leg P1. The winding of the coil 20B is wound around the leg P2 counterclockwise. A terminal T1 and a terminal T2 are provided at the end of the coil 10B on the yoke Y1 side and the end of the coil 20B on the yoke Y1 side (the beginning of winding of the coil 10B and the beginning of winding of the coil 20B), respectively. The end of the coil 10B on the yoke Y2 side and the end of the coil 20B on the yoke Y2 side (the end of winding of the coil 10B and the end of winding of the coil 20B) are connected.
The yoke Y1, the yoke Y2, the leg part P1, and the leg part P2 form a rectangular part. Extended yoke Y4 and extended yoke Y3 and legs P3 is a path for the magnetic flux [Phi _L2 leakage and leakage flux [Phi _L1. In the current limiting coil 1C, the leakage flux Φ _L1 and the leakage flux Φ _L2 can pass not only in the air but also through the extension yoke Y3, the leg portion P3, and the extension yoke Y4. For this reason, in the current-limiting coil 1C, the leakage flux Φ _L1 and the leakage flux Φ _L2 are larger than those in the current-limiting coil 1B, and the coupling coefficient between the coils 10B and 20B is even smaller than that in the current-limiting coil 1B.

FIG. 8 shows an example of the configuration of a current limiting coil 1D having a core 30C in which a leakage magnetic flux path is added in the middle of the rectangular portion.
Current limiting coil 1D includes a coil 10B, a coil 20B, and a core 30C.
The core 30C includes a yoke Y1, a yoke Y2, a leg part P1, a leg part P2, and a leg part P4. The yoke Y1 and the yoke Y2 face each other. The leg P1 connects the left end of the yoke Y1 and the left end of the yoke Y2. The leg P2 connects the right end of the yoke Y1 and the right end of the yoke Y2. The leg part P4 connects the intermediate part of the yoke Y1 and the intermediate part of the yoke Y2. However, the leg part P4 has a gap (gap) AG2 in the middle.
The coil 10B and the coil 20B in the current limiting coil 1D are the same as those of the current limiting coil 1B. That is, the winding of the coil 10B is wound clockwise around the leg P1. The winding of the coil 20B is wound around the leg P2 counterclockwise. A terminal T1 and a terminal T2 are provided at the end of the coil 10B on the yoke Y1 side and the end of the coil 20B on the yoke Y1 side (the beginning of winding of the coil 10B and the beginning of winding of the coil 20B), respectively. The end of the coil 10B on the yoke Y2 side and the end of the coil 20B on the yoke Y2 side (the end of winding of the coil 10B and the end of winding of the coil 20B) are connected.
The leg part P4 becomes a path of the leakage magnetic flux Φ _L1 and the leakage magnetic flux Φ _L2 . In the current limiting coil 1D, the leakage magnetic flux Φ _L1 and the leakage magnetic flux Φ _L2 can pass through the leg portion P4 as well as in the air. For this reason, in the current limiting coil 1D, the leakage flux Φ _L1 and the leakage flux Φ _L2 are larger than those in the current limiting coil 1B, and the coupling coefficient between the coil 10B and the coil 20B is further smaller than that in the current limiting coil 1B.

  In addition, the structure of the current-limiting coil 1 shown in FIGS. 5 to 8 is an example and is not limited. In addition to these, there may be various current limiting coils 1. For example, the core 30 may have various shapes such as an EI core, an EE core, and a UU core.

  As described above, according to the present invention, it is possible to accelerate the rise of current immediately after a large voltage is applied, and to suppress an increase in current as time elapses. For this reason, by inserting the current-limiting coil for DC power supply of the present invention in the middle of the DC power supply line, the operating time of the circuit breaker, the fuse, etc. can be shortened and an excessive current can be prevented from being suddenly generated. Can do.

  Although the embodiments of the present invention have been described above, various modifications and combinations required for design reasons and other factors are described in the inventions described in the claims and in the embodiments of the invention. It is included in the scope of the invention corresponding to the example.

1, 1A, 1B, 1C, 1D ... Current-limiting coil, 10, 10A, 10B ... Coil, 20, 20A, 20B ... Coil, 30, 30A, 30B, 30C ... Core, Y1, Y2 ... Yoke, Y3, Y4 ... Expansion yoke, P1, P2, P3, P4 ... Leg part, AG1, AG2 ... Gap (gap)

Claims (5)

A current-limiting coil for DC power supply used in DC power supply,
A core made of a material that allows easy passage of magnetic flux,
Two coils wound around the core and differentially connected;
A current-limiting coil for direct current power supply, comprising: The core includes a first yoke and a second yoke facing each other, a first leg connecting one end of the first yoke and one end of the second yoke, and the first A second leg connecting the other end of the one yoke and the other end of the second yoke;
The two coils are wound around the first leg or the second leg,
The current-limiting coil for DC power supply according to claim 1, wherein The core includes a first yoke and a second yoke facing each other, a first leg connecting one end of the first yoke and one end of the second yoke, and the first A second leg connecting the other end of the one yoke and the other end of the second yoke;
One of the two coils is wound around the first leg,
Another one of the two coils is wound around the second leg,
The current-limiting coil for DC power supply according to claim 1, wherein The core includes a first yoke and a second yoke facing each other, a first leg connecting one end of the first yoke and one end of the second yoke, and the first A second leg connecting the other end of one yoke and the other end of the second yoke; a first extension yoke extending from the other end of the first yoke; A second extension yoke extending from the other end of the second yoke; an end of the first extension yoke opposite to the first yoke; and the second extension yoke. And a third leg portion having a gap in the middle thereof, and connecting the yoke and the opposite end portion,
One of the two coils is wound around the first leg,
Another one of the two coils is wound around the second leg,
The current-limiting coil for DC power supply according to claim 1, wherein The core includes a first yoke and a second yoke facing each other, a first leg connecting one end of the first yoke and one end of the second yoke, and the first A second leg connecting the other end of the one yoke and the other end of the second yoke, an intermediate portion of the first yoke and an intermediate portion of the second yoke; A third leg having a gap in the middle;
One of the two coils is wound around the first leg,
Another one of the two coils is wound around the second leg,
The current-limiting coil for DC power supply according to claim 1, wherein

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