JP2006186620A - Line filter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a line filter capable of improving high-frequency band characteristic as a filter by electrostatically separating inductors from each other, even if a plurality of inductors are closely arranged on a line to attain miniaturization. <P>SOLUTION: First and second winding wires 11 and 12 are differently wound around cores 21 and 22 to constitute first and second inductors, thereby magnetically separating each of the conductors. Also, a metal-made shielding member 20 is closely provided on each of the cores 21 and 22 and grounded, thereby electrostatically separating each of the conductors. Further, stray capacitance is formed between each of the cores 21, 22 and the grounding surface, thereby equivalently forming a T-type filter by the stray capacitance and each of the inductors without adding a different capacitor to improve the high-frequency band characteristic. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a line filter that suppresses noise propagating on a conductive wire.

  Power electronics devices such as switching power supplies, inverters, lighting circuits for lighting devices, and the like have a power conversion circuit that converts power. The power conversion circuit has a switching circuit that converts direct current into rectangular alternating current. For this reason, the power conversion circuit generates a ripple voltage having a frequency equal to the switching frequency of the switching circuit and noise associated with the switching operation of the switching circuit. This ripple voltage and noise adversely affect other devices. Therefore, it is necessary to provide a means for reducing ripple voltage and noise between the power conversion circuit and another device or line.

  Recently, power line communication has been considered promising as a communication technique used in building a communication network in the home, and its development is being promoted. In power line communication, communication is performed by superimposing a high-frequency signal on the power line. In this power line communication, noise is generated on the power line due to the operation of various electric / electronic devices connected to the power line, which causes a decrease in communication quality such as an increase in error rate. Therefore, a means for reducing noise on the power line is required. In power line communication, it is necessary to prevent a communication signal on the indoor power line from leaking to the outdoor power line.

  Noise that propagates through two conductive lines includes normal mode (differential mode) noise that causes a potential difference between the two conductive lines, and common mode noise that propagates through the two conductive lines in the same phase. There is.

  In order to suppress these noises, it is effective to provide a line filter in a power supply line, a signal line, or the like. As the line filter, a filter including an inductance element (inductor) and a capacitor, a so-called LC filter is often used. The LC filter includes a T-type filter and a π-type filter in addition to one having one inductance element and one capacitor. The basic configuration of the T-type filter includes first and second inductors connected in series on a line, and one end of a capacitor is connected between the first and second inductors. .

By the way, in the case of a line filter having a plurality of inductors, when each inductor is magnetically or electrostatically coupled, a high-frequency noise component is transmitted, and the filter performance at high frequencies is reduced. It may end up. In Patent Document 1, two inductors are inserted in two lines, and a total of four inductors are inserted, and in an AC line filter having a configuration in which a capacitor is connected between the inductors of each line, the arrangement of each inductor and capacitor is optimal. In addition, there is described an invention in which a magnetic induction plate is arranged between a predetermined inductor and a capacitor to suppress magnetic coupling and suppress noise components.
JP 2004-228822 A

  However, simply disposing a magnetic field induction plate as described in Patent Document 1 only suppresses magnetic coupling and does not consider electrostatic coupling. For this reason, after all, a capacitor for removing the high frequency component is separately required. In Patent Document 1, it is assumed that two inductors on a line are arranged orthogonally to each other and a magnetic field induction plate is arranged. For example, the case where two inductors on a line are arranged linearly is not considered. However, in order to reduce the size of the circuit, there are cases where it is desired to arrange two inductors in a linear proximity on the line. On the other hand, particularly in the case of a T-type filter, it is particularly advantageous for noise characteristics in a high frequency range that the two inductors on the line are not magnetically and electrostatically coupled. For this reason, when it arranges simply near, coupling will arise and there exists a problem that the performance as a filter will fall.

  The present invention has been made in view of such a problem, and the object thereof is to perform a filter by electrostatically separating the inductors from each other even if a plurality of inductors are arranged close to each other on the line for miniaturization. It is an object of the present invention to provide a line filter that can improve the high frequency characteristics.

  A line filter according to the present invention includes a plurality of inductors each connected in series on a first conductive line, each including a core and a winding wound around the core, and a shielding member made of metal, The cores constituting the inductor are arranged close to each other, and the shielding member is arranged so as to be close to each core at least between the adjacent cores, and is grounded.

  In the line filter according to the present invention, the inductors are electrostatically separated from each other because the shielding member made of metal is disposed between the adjacent cores, and close to the core and grounded. Further, by separating the cores, the inductors are magnetically separated from each other. This prevents deterioration of the high frequency characteristics due to magnetic and electrostatic coupling. Furthermore, since a stray capacitance is formed between each core and the ground plane (ground plane), a T-type filter can be equivalently formed by each stray capacitance and each separated inductor without adding a separate capacitor. This also improves the high frequency characteristics.

  In the line filter according to the present invention, the insulating pressing member may be integrally wound around the outer peripheral portion of each core and the shielding member.

In the line filter according to the present invention, the plurality of inductors on the first conductive line include a first inductor including a first core and a first winding, and a second core and a second winding. And a third inductor and a fourth inductor connected in series on the second conductive line. The third inductor includes a third winding wound around the first core together with the first winding, and the fourth inductor is wound around the second core together with the second winding. The fourth core may be included, and the first core and the second core may be arranged close to each other. The shielding member may be disposed so as to be close to the first and second cores at least between the first core and the second core, and may be grounded.
In this case, the shielding member made of metal is disposed between the first core and the second core, is close to the first and second cores, and is grounded, so that the first and third The inductor set and the second and fourth inductor sets are electrostatically separated. Further, since the core is divided into the first core and the second core, the first and third inductor sets and the second and fourth inductor sets are magnetically separated. The

Furthermore, a fifth inductor including a fifth winding, one end of which is connected in the middle of the first winding, and a sixth winding, one end of which is in the middle of the third winding. A sixth inductor connected may be further provided. Then, the fifth and sixth windings may be wound around the first core together with the first and third windings.
In this case, the first and third inductors, the fifth and sixth inductor sets, and the second and fourth inductor sets are electrostatically separated by the shielding member. Moreover, since the cores are separated, they are magnetically separated.

Still further, it includes a seventh inductor, one end of which is connected in the middle of the first winding, and an eighth winding, one end of which is in the middle of the third winding. An eighth inductor connected may be further provided. The seventh and eighth windings may be wound around the second core together with the second and fourth windings.
In this case, the shielding member causes the first and third inductors, the fifth and sixth inductor sets, the second and fourth inductors, and the seventh and eighth inductor sets to electrostatically Separated. Moreover, since the cores are separated, they are magnetically separated.

  According to the line filter of the present invention, since the shielding member made of metal is arranged between the adjacent cores so as to be close to each core and grounded, a plurality of inductors are arranged close to each other on the line. Even if the size is reduced, the inductors can be electrostatically separated from each other, and deterioration of the high frequency characteristics can be prevented. In addition, since a stray capacitance is formed between each core and the ground plane, a T-type filter is equivalently formed by the stray capacitance and each separated inductor without adding a separate capacitor. This also improves the high frequency characteristics.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[First Embodiment]
First, the line filter according to the first embodiment of the present invention will be described. 1A and 1B show a configuration example of a line filter according to the present embodiment. The line filter is made of a magnetic material and is linearly adjacent to and adjacent to each other, the first and second cores 21 and 22, the first winding 11 wound around the first core 21, The second winding 12 wound around the two cores 22 and the shielding member 20 that is disposed so as to be close to the cores 21 and 22 in the cores 21 and 22 and grounded. In this line filter, each of the cores 21 and 22 is grounded via the shielding member 20, but it is preferable that the ground plane is not close to the windings 11 and 12. The arrangement of the shielding member 20 so as to be close to each of the cores 21 and 22 is not limited to the case where the shielding member 20 is in direct contact with each of the cores 21 and 22, for example, by coating the shielding member 20. A case where a one-layer film is added may be used, or a case where a gap is provided between the shielding member 20 and each of the cores 21 and 22 may be used. Furthermore, the coating process may be performed on each of the cores 21 and 22.

  As shown in FIG. 2, for example, a tape-shaped insulating pressing member 30 may be integrally wound around the outer peripheral portions of the cores 21 and 22 and the shielding member 20.

  The shielding member 20 is made of a metal material that is electrically conductive and magnetically and electrostatically shielded, and is made of, for example, a copper plate. In FIGS. 1A and 1B, the black circles marked on the windings 11 and 12 indicate the polarity (start of winding) of the windings. In this line filter, since the cores 21 and 22 are magnetically separated by using the separate cores 21 and 22, the relationship of the polarity direction between the cores 21 and 22 is not particularly limited. Further, the relationship of the direction of the magnetic path between the cores 21 and 22 is not particularly limited. FIG. 1B shows a configuration example in which the polarity of the second winding 12 is opposite to the configuration of FIG. 1A, but the polarity relationship is not limited to the illustrated state. Other states may be used.

  The first and second windings 11 and 12 are connected in series with each other. The first and second cores 21 and 22 may each be formed of a split core. Further, the shape of the first and second cores 21 and 22 is not particularly limited to the illustrated rectangular shape as long as it forms a closed magnetic circuit.

  FIG. 3 shows an equivalent circuit of the line filter shown in FIGS. This line filter equivalently constitutes an unbalanced T-type filter, and functions as a normal mode filter that suppresses normal mode noise. This equivalent circuit includes first and second inductors L1 and L2 connected in series on the first conductive line 3 between the input / output terminals 1A and 2A, and one end of the first and second inductors L1. , L2 and a first capacitor C1 having the other end grounded. The first inductor L <b> 1 is formed by winding the first winding 11 around the first core 21. The second inductor L <b> 2 is formed by winding the second winding 12 around the second core 22. The first capacitor C1 is a stray capacitance formed between the cores 21 and 22 and the ground plane (ground plane). A capacitor other than the stray capacitance component can be added separately.

  In this line filter, the first inductor L1 and the second inductor L2 are configured by using separate cores 21 and 22, respectively, so that the first inductor L1 and the second inductor L2 are magnetically separated. Is done. Further, since the shielding member 20 made of metal is close to the cores 21 and 22 and grounded, the first inductor L1 and the second inductor L2 are also electrostatically separated. This prevents deterioration of the high frequency characteristics due to magnetic and electrostatic coupling. Further, since the stray capacitance is formed between each of the cores 21 and 22 and the ground plane, the stray capacitance and each of the separated inductors L1 and L2 are equivalently shown in FIG. 3 without adding a separate capacitor. A T-type filter as shown in FIG. This also improves the high frequency characteristics.

As described above, according to the present embodiment, each of the cores 21 and 22 is configured by using the separate cores 21 and 22 and the shielding member 20 made of metal between the adjacent cores 21 and 22. Since the inductors L1 and L2 are arranged close to each other and grounded, the inductors L1 and L2 are arranged close to each other on the first conductive wire 3 to achieve miniaturization. In addition, electrostatic separation can be performed, and high frequency characteristics can be improved.
[Second Embodiment]

  Next, a line filter according to a second embodiment of the present invention will be described. 4A and 4B show a configuration example of the line filter according to the present embodiment. In addition, the same code | symbol is attached | subjected to the substantially same component as the line filter which concerns on the said 1st Embodiment shown to FIG. 1 (A), (B). This line filter includes a third winding 13 wound around the first core 21 and a fourth winding wound around the second core 22 in addition to the components shown in FIGS. Line 14. Also in this line filter, the cores 21 and 22 are grounded via the shielding member 20, but it is preferable that the ground plane is not close to the windings 11 to 14.

  As with the line filter according to the first embodiment, this line filter also has, for example, a tape-like insulating property on the outer peripheral portion of each of the cores 21 and 22 and the shielding member 20, as shown in FIG. The pressing member 30 may be integrally wound.

4A and 4B, the black circles marked on the windings 11 to 14 indicate the polarity (start of winding) of the windings. In this line filter, since the cores 21 and 22 are magnetically separated by using the separate cores 21 and 22, the relationship of the polarity direction between the cores 21 and 22 is not particularly limited. Moreover, the relationship of the direction of the magnetic path between each core 21 and 22 is not specifically limited. FIG. 4B shows a configuration example in which the polarities of the second and fourth windings 12 and 14 are reversed with respect to the configuration of FIG. It is not limited to this, and other states may be used.
The first and third windings 11 and 13 are magnetically coupled to each other so as to cooperate and suppress common mode noise by being wound around a common first core 21. That is, the first and third windings 11 and 13 are oriented so that the magnetic fluxes induced in the first core 21 are offset by the currents flowing through the windings when normal mode current flows through them. Are wound around the first core 21. As described above, the first and third windings 11 and 13 and the first core 21 constitute a common mode choke coil that suppresses common mode noise and allows a normal mode signal to pass. Similarly, the second and fourth windings 12 and 14 are wound around the common second core 22 so as to be magnetically coupled to each other so as to suppress common mode noise in cooperation. The coil is configured.

  The first and second windings 11 and 12 are connected in series with each other. The third and fourth windings 13 and 14 are also connected in series with each other. The first and second cores 21 and 22 are respectively C-shaped first and second cores (C-type cores) 21C and 22C, and I-shaped first and second cores (I-type). Core) It is composed of a combination of split cores (CI core) composed of 21I and 22I. The first and second I-type cores 21I and 22I are adjacent to each other, and the shielding member 20 is disposed therebetween. The first and third windings 11 and 13 are wound around the first C-type core 21C, and the second and fourth windings 12 and 14 are wound around the second C-type core 22C. In the present embodiment also, the first and second cores 21 and 22 have the shapes shown in FIGS. 4A and 4B as long as they form a closed magnetic circuit. The present invention is not limited, and various configurations are conceivable as modified examples described later.

  FIG. 6 shows an equivalent circuit of the line filter shown in FIGS. 4 (A) and 4 (B). Components substantially the same as the equivalent circuit of the line filter according to the first embodiment shown in FIG. 3 are denoted by the same reference numerals. This line filter is equivalently configured as a common mode type T filter and functions as a common mode filter that suppresses common mode noise propagating through the first and second conductive lines 3 and 4 in the same phase. To do. This equivalent circuit includes, in addition to the components of the equivalent circuit of FIG. 3, third and fourth inductors L3 and L4 connected in series on the second conductive line 4 between the input / output terminals 1B and 2B. A second capacitor C2 having one end connected between the third and fourth inductors L3 and L4 and the other end grounded. The third inductor L3 is formed by winding the third winding 13 around the first core 21 common to the first inductor L1. The fourth inductor L4 is formed by winding the fourth winding 14 around the second core 22 common to the second inductor L2. Similar to the first capacitor C1, the second capacitor C2 is a stray capacitance formed between the cores 21 and 22 and the ground plane (ground plane). A capacitor other than the stray capacitance component can be added separately.

  In this line filter, the set of the first and third inductors L1 and L3 and the set of the second and fourth inductors L2 and L4 are configured using separate cores 21 and 22, respectively. They are magnetically separated from each other. Moreover, since the shielding member 20 made of metal is close to each of the cores 21 and 22 and grounded, the set is also electrostatically separated from each other. This prevents deterioration of the high frequency characteristics due to magnetic and electrostatic coupling. Further, since a stray capacitance is formed between each of the cores 21 and 22 and the ground plane, a common mode T-type filter as shown in FIG. 6 is equivalently formed without adding a separate capacitor. The This also improves the high frequency characteristics.

  FIG. 7 is a graph in which this line filter is actually manufactured and the frequency characteristics of the attenuation are measured and graphed. The horizontal axis represents frequency (Hz), and the vertical axis represents attenuation (dB). In the equivalent circuit of FIG. 6, the inductance of the first and third inductors L1 and L3 is set to 4 mH, and the inductance of the second and fourth inductors L2 and L4 is set to 4 mH. The capacitances of the first and second capacitors C1, C2 were each set to 1500 pF. Since the capacitance formed by the stray capacitance component is small, an external capacitor was added separately to make the capacitance 1500 pF. The input / output impedance of the signal was 50Ω. As a comparative example, the characteristics were measured when the cores were in contact with each other without providing the shielding member 20 with the same circuit configuration in terms of equivalent circuits.

  As can be seen from the results of FIG. 7, when the shielding member 20 is not provided (no shielding), even if an external capacitor is added, if the cores 21 and 22 are brought into contact with each other, the attenuation in the high range is insufficient. The high frequency characteristics are degraded. On the other hand, in the case of the line filter according to the present embodiment provided with the shielding member 20 (with a shield), the high frequency characteristics are improved.

  FIG. 8 shows a configuration in which Y capacitors C11 and C12 are further added to the signal output side as external capacitors in the line filter according to the present embodiment. One end of the Y capacitor C11 is connected to the second inductor L2 side on the first conductive line 3, and the other end is grounded. One end of the Y capacitor C12 is connected to the fourth inductor L4 side on the second conductive line 4, and the other end is grounded.

  FIG. 9 is a graph in which a line filter to which such Y capacitors C11 and C12 are added is actually manufactured, and the frequency characteristics of the attenuation are measured and graphed. The capacitances of the Y capacitors C11 and C12 were each set to 330 pF. The other circuit conditions are the same as in FIG. As a comparative example, the characteristics when the shielding member 20 was not provided with the same circuit configuration as an equivalent circuit were also measured (no shield). As can be seen from the results of FIG. 9, when the shielding member 20 is provided and the Y capacitors C11 and C12 are added (with shielding), the high frequency characteristics are further improved.

As described above, according to the present embodiment, each of the cores 21 and 22 is configured by using the separate cores 21 and 22 and the shielding member 20 made of metal between the adjacent cores 21 and 22. Since the coils are arranged close to each other and grounded, the inductors L1 and L2 are arranged close to each other on the first conductive line 3 and the inductors L3 and L4 are arranged close to each other on the second conductive line 4. Even if the size is reduced, magnetic and electrostatic separation between the first and third inductors L1 and L3 and the second and fourth inductors L2 and L4 can be performed. High frequency characteristics can be improved.
<Modification of Second Embodiment>

  Next, a modification of the line filter according to the present embodiment will be described. In the modification described below, only the configurations of the first and second cores 21 and 22 are different, and the other configurations are basically the same as the configuration examples of FIGS. 4A and 4B described above. . Further, in the following modifications, the relationship of the magnetic path direction between the cores 21 and 22 is not particularly limited. Further, the polarity relationship between the cores 21 and 22 is not limited to the illustrated state, and may be in another state.

  FIG. 10 shows a first modification. In this modified example, the first and second cores 21 and 22 are the same as the first and second C-type cores 21C and 22C, respectively, as in the configuration example of FIGS. 4A and 4B. It is composed of a combination of split cores (CI cores) composed of two I-type cores 21I and 22I. However, in this modification, the arrangement of the divided cores is reversed as compared with FIGS. 4 (A) and 4 (B). That is, the first and second I-type cores 21I and 22I are arranged on the outer side, the first and second C-type cores 21C and 22C are adjacent to each other, and the shielding member 20 is arranged therebetween. .

  FIG. 11 shows a second modification. In this modification, each of the first cores 21 and 22 is an E-shaped split core (E-type core). That is, the first core 21 is composed of a combination of two E-type cores 21E1 and 21E2 (EE core). The two E-type cores 21E1 and 21E2 are arranged so as to face each other vertically, and the first and third windings 11 and 13 are wound around the central column portion of each E-type core 21E1 and 21E2. Similarly, the second core 22 is composed of a combination of two E-type cores 22E1 and 22E2 arranged vertically opposite to each other, and the second and fourth windings are provided in the central column portion of each E-type core 22E1 and 22E2. 12 and 14 are wound.

  12A and 12B show a third modification. In this modification, each of the first cores 21 and 22 is a PQ core. 12A is a side view and FIG. 12B is a top view. In this modification, the first core 21 is composed of a combination of two PQ cores 21P1 and 21P2. The two PQ cores 21P1 and 21P2 are arranged so as to face each other vertically, and the first and third windings 11 and 13 are wound around the central column portion of each PQ core 21P1 and 21P2. Similarly, the second core 22 is composed of a combination of two PQ cores 22P1 and 22P2 arranged vertically opposite to each other, and the second and fourth windings 12, 14 is wound.

  FIG. 13 shows a fourth modification. In this modification, each of the first cores 21 and 22 is a C-shaped split core (C-type core). That is, the 1st core 21 is comprised by the combination (CC core) of two C type cores 21C1 and 21C2. The two C-type cores 21C1 and 21C2 are arranged so as to face each other vertically, and the first and third windings 11 and 13 are wound around the column portions outside the C-type cores 21C1 and 21C2. Similarly, the second core 22 is composed of a combination of two C-type cores 22C1 and 22C2 that are vertically opposed to each other, and the second and fourth windings are provided on the column portions outside the C-type cores 22C1 and 22C2. 12 and 14 are wound.

  FIG. 14 shows a fifth modification. This modification is an example in which the first cores 21 and 22 are each constituted by a single core having a square shape. That is, the first core 21 is configured as one square-shaped core, and the first and third windings 11 and 13 are wound around the upper and lower pillar portions. Similarly, the second core 22 is configured as one square-shaped core, and the second and fourth windings 12 and 14 are wound around the upper and lower pillar portions thereof.

FIG. 15 shows a sixth modification. This modification is an example in which the first cores 21 and 22 are each constituted by a single core having a Japanese character shape. That is, the first core 21 is configured by placing a single Japanese-shaped core horizontally, and the first and third windings 11 and 13 are wound around the central column portion. Similarly, the second core 22 is configured by horizontally placing one day-shaped core, and the second and fourth windings 12 and 14 are wound around the central pillar portion.
[Third Embodiment]

  Next, a line filter according to a third embodiment of the present invention will be described. FIG. 16 shows a configuration example of the line filter according to the present embodiment. In addition, the same code | symbol is attached | subjected to the component substantially the same as the line filter which concerns on the said 2nd Embodiment. This line filter includes fifth and sixth windings 15 and 16 wound around the first core 21 in addition to the components of the line filter according to the second embodiment. As shown in an equivalent circuit of FIG. 17 described later, one end of the fifth winding 15 is connected to the middle of the first winding 11 (preferably the midpoint of the first winding 11), and the sixth winding One end of the wire 16 is connected to the middle of the third winding 13 (preferably the midpoint of the third winding 13).

  Although not shown, this line filter also has, for example, a tape-like insulating property on the outer peripheral portion of each of the cores 21 and 22 and the shielding member 20 as in the case of the line filters according to the first and second embodiments. The pressing member 30 may be integrally wound.

  In FIG. 16, black circles marked on the windings 11 to 16 indicate the polarity (start of winding) of the windings. In this line filter, since the cores 21 and 22 are magnetically separated by using the separate cores 21 and 22, the relationship of the polarity direction between the cores 21 and 22 is not particularly limited. Further, the relationship of the direction of the magnetic path between the cores 21 and 22 is not particularly limited.

  The first core 21 is configured by a combination (EE core) of two E-type cores 21E1 and 21E2. The two E-type cores 21E1 and 21E2 are arranged so as to face each other vertically, and the first and third windings 11 and 13 are wound around the central column portion of each E-type core 21E1 and 21E2. Further, fifth and sixth windings 15 and 16 are wound around the column portions outside the E-type cores 21E1 and 21E2. On the other hand, the 2nd core 22 is comprised by the combination (CC core) of two C type cores 22C1 and 22C2. The two C-type cores 22C1 and 22C2 are arranged so as to face each other vertically, and the second and fourth windings 12 and 14 are wound around the column portions outside the C-type cores 22C1 and 22C2. Also in this embodiment, the shape of the first and second cores 21 and 22 is not particularly limited to the shape shown in FIG. 16 as long as it forms a predetermined closed magnetic circuit. Although not shown, various modifications are possible.

  FIG. 17 shows an equivalent circuit of the line filter shown in FIG. Components substantially the same as those of the equivalent circuit of the line filter according to the second embodiment shown in FIG. 6 are denoted by the same reference numerals. This line filter also functions as a common mode filter. This equivalent circuit includes the fifth winding 15 in addition to the components of the equivalent circuit of FIG. 6, and one end thereof is connected to the middle of the first winding 11 (preferably the midpoint of the first winding 11). The fifth inductor L5 and the sixth inductor L6 including the sixth winding 16 and one end of which is connected to the middle of the third winding 13 (preferably the midpoint of the third winding 13). And. This equivalent circuit further includes a third capacitor C3 having one end connected to the other ends of the fifth and sixth inductors L5 and L6 and the other end grounded.

  The fifth inductor L5 is formed by winding the fifth winding 15 around the first core 21 common to the first inductor L1. Similarly, the sixth inductor L <b> 6 is formed by winding the sixth winding 16 around the first core 21. Similar to the first and second capacitors C1 and C2, the third capacitor C3 is a stray capacitance formed between the cores 21 and 22 and the ground plane (ground plane). A capacitor other than the stray capacitance component can be added separately.

  In this line filter, the first and third inductors L1 and L3, the fifth and sixth inductors L5 and L6, and the second and fourth inductors L2 and L4 are separated into separate cores 21, By using 22, those sets are magnetically separated from each other. Moreover, since the shielding member 20 made of metal is close to each of the cores 21 and 22 and grounded, the set is also electrostatically separated from each other. This prevents deterioration of the high frequency characteristics due to magnetic and electrostatic coupling. Furthermore, since a stray capacitance is formed between each of the cores 21 and 22 and the ground plane, a common mode filter as shown in FIG. 17 is equivalently formed without adding a separate capacitor. This also improves the high frequency characteristics.

As described above, according to the present embodiment, each of the cores 21 and 22 is configured by using the separate cores 21 and 22 and the shielding member 20 made of metal between the adjacent cores 21 and 22. Since the coils are arranged close to each other and grounded, the inductors L1 and L2 are arranged close to each other on the first conductive line 3 and the inductors L3 and L4 are arranged close to each other on the second conductive line 4. Even if a reduction in size is achieved, the first and third inductors L1 and L3, and the combination of the fifth and sixth inductors L5 and L6 and the second and fourth inductors L2 and L4, In addition, electrostatic separation can be performed, and high frequency characteristics can be improved.
[Fourth Embodiment]

  Next, a line filter according to a fourth embodiment of the present invention will be described. FIG. 18 shows a configuration example of the line filter according to the present embodiment. In addition, the same code | symbol is attached | subjected to the component substantially the same as the line filter which concerns on the said 3rd Embodiment shown in FIG. This line filter includes seventh and eighth windings 17 and 18 wound around the second core 22 in addition to the components of the line filter of FIG. As shown in an equivalent circuit of FIG. 19 to be described later, one end of the seventh winding 17 is connected to the middle of the second winding 12 (preferably the midpoint of the second winding 12), and the eighth winding One end of the wire 18 is connected to the middle of the fourth winding 14 (preferably the midpoint of the fourth winding 14).

  Although not shown in the figure, also for this line filter, for example, a tape-shaped insulating pressing member 30 is integrated with the outer peripheral portion of each of the cores 21 and 22 and the shielding member 20 as in the case of the line filter according to each of the above embodiments. It may be wound.

  In FIG. 18, black circles marked on the windings 11 to 18 indicate the polarity (winding start) of the windings. In this line filter, since the cores 21 and 22 are magnetically separated by using the separate cores 21 and 22, the relationship of the polarity direction between the cores 21 and 22 is not particularly limited. Further, the relationship of the direction of the magnetic path between the cores 21 and 22 is not particularly limited.

  The first core 21 is configured by a combination (EE core) of two E-type cores 21E1 and 21E2 as in the line filter of FIG. Similarly, the second core 22 is composed of a combination of two E-type cores 22E1 and 22E2 arranged vertically opposite to each other, and the second and fourth windings are provided in the central column portion of each E-type core 22E1 and 22E2. 12 and 14 are wound. And the 7th and 8th coil | windings 17 and 18 are wound by the column part of the outer side of each E type | mold core 22E1 and 22E2. Also in this embodiment, the shape of the first and second cores 21 and 22 is not particularly limited to the shape shown in FIG. 18 as long as it forms a predetermined closed magnetic circuit. Although not shown, various modifications are possible.

  FIG. 19 shows an equivalent circuit of the line filter shown in FIG. Components that are substantially the same as those of the equivalent circuit of the line filter according to the third embodiment shown in FIG. 17 are denoted by the same reference numerals. This line filter also functions as a common mode filter. This equivalent circuit includes a seventh winding 17 in addition to the components of the equivalent circuit of FIG. 17, and one end thereof is connected to the middle of the second winding 12 (preferably the midpoint of the second winding 12). The eighth inductor L8 including the seventh inductor L7 and the eighth winding 18 and having one end connected to the middle of the fourth winding 14 (preferably the midpoint of the fourth winding 14). And. The equivalent circuit further includes a fourth capacitor C4 having one end connected to the other ends of the seventh and eighth inductors L7 and L8 and the other end grounded.

  The seventh inductor L7 is formed by winding the seventh winding 17 around the second core 22 common to the second inductor L2. Similarly, the eighth inductor L <b> 8 is formed by winding the eighth winding 18 around the second core 22. Similar to the first to third capacitors C1 to C3, the fourth capacitor C4 is a stray capacitance formed between the cores 21 and 22 and the ground plane (ground plane). A capacitor other than the stray capacitance component can be added separately.

  In this line filter, the first and third inductors L1 and L3, the combination of the fifth and sixth inductors L5 and L6, the second and fourth inductors L2 and L4, and the seventh and eighth inductors L7 , L8 are configured using separate cores 21 and 22, respectively, so that the sets are magnetically separated from each other. Moreover, since the shielding member 20 made of metal is close to each of the cores 21 and 22 and grounded, the set is also electrostatically separated from each other. This prevents deterioration of the high frequency characteristics due to magnetic and electrostatic coupling. Further, since a stray capacitance is formed between each of the cores 21 and 22 and the ground plane, a common mode filter as shown in FIG. 19 is equivalently formed without adding a separate capacitor. This also improves the high frequency characteristics.

  As described above, according to the present embodiment, each of the cores 21 and 22 is configured by using the separate cores 21 and 22 and the shielding member 20 made of metal between the adjacent cores 21 and 22. Since the coils are arranged close to each other and grounded, the inductors L1 and L2 are arranged close to each other on the first conductive line 3 and the inductors L3 and L4 are arranged close to each other on the second conductive line 4. Even if the size is reduced, the first and third inductors L1 and L3, the combination of the fifth and sixth inductors L5 and L6, the second and fourth inductors L2 and L4, and the seventh and eighth inductors Magnetic and electrostatic separation from the set of inductors L7 and L8 can be performed, and high frequency characteristics can be improved.

  Note that the line filter according to each embodiment reduces the ripple voltage and noise generated by the power conversion circuit, reduces noise on the power line in power line communication, and communication signals on the indoor power line are connected to the outdoor power line. It can be used as a means for preventing leakage.

  In addition, this invention is not limited to said each embodiment, A various change is possible. For example, in each of the above embodiments, the case where the shielding is performed so as to be largely separated into two parts by one shielding member 20 has been described. However, the two or more shielding members 20 are separated into three or more parts. Shielding is also possible. For example, when three inductors are arranged in series on one conductive line, a shielding member 20 may be provided between the inductors, and the inductors may be separated electrostatically and magnetically. In this case, the two shielding members 20 are shielded so as to be separated into three parts.

It is an external view which shows one structural example of the line filter which concerns on the 1st Embodiment of this invention. It is an external view which shows the other structural example of the line filter which concerns on the 1st Embodiment of this invention. FIG. 3 is a circuit diagram showing an equivalent circuit of the line filter according to the first embodiment of the present invention. It is an external view which shows one structural example of the line filter which concerns on the 2nd Embodiment of this invention. It is an external view which shows the other structural example of the line filter which concerns on the 2nd Embodiment of this invention. It is a circuit diagram which shows the equivalent circuit of the line filter which concerns on the 2nd Embodiment of this invention. It is the figure which made the graph the frequency characteristic of the attenuation amount of the line filter which concerns on the 2nd Embodiment of this invention compared with the past. It is a circuit diagram which shows the circuit example which improved the line filter which concerns on the 2nd Embodiment of this invention. It is the figure which made the graph the frequency characteristic of the attenuation amount of the improved filter circuit compared with the past. It is an external view which shows the 1st modification of the line filter which concerns on the 2nd Embodiment of this invention. It is an external view which shows the 2nd modification of the line filter which concerns on the 2nd Embodiment of this invention. It is an external view which shows the 3rd modification of the line filter which concerns on the 2nd Embodiment of this invention. It is an external view which shows the 4th modification of the line filter which concerns on the 2nd Embodiment of this invention. It is an external view which shows the 5th modification of the line filter which concerns on the 2nd Embodiment of this invention. It is an external view which shows the 6th modification of the line filter which concerns on the 2nd Embodiment of this invention. It is an external view which shows one structural example of the line filter which concerns on the 3rd Embodiment of this invention. It is a circuit diagram which shows the equivalent circuit of the line filter which concerns on the 3rd Embodiment of this invention. It is an external view which shows one structural example of the line filter which concerns on the 4th Embodiment of this invention. It is a circuit diagram which shows the equivalent circuit of the line filter which concerns on the 4th Embodiment of this invention.

Explanation of symbols

C1 ... 1st capacitor, C2 ... 2nd capacitor, L1 ... 1st inductor, L2 ... 2nd inductor, L3 ... 3rd inductor, L4 ... 4th inductor, 3 ... 1st conductive wire, DESCRIPTION OF SYMBOLS 4 ... 2nd conductive wire, 11 ... 1st winding, 12 ... 2nd winding, 13 ... 3rd winding, 14 ... 4th winding, 20 ... Shielding member, 21 ... 1st Core, 22 ... second core, 30 ... pressing member.

Claims (5)

A plurality of inductors connected in series with each other on a first conductive line, each including a core and a winding wound around the core;
A shielding member made of metal,
The cores constituting each inductor are arranged close to each other,
The line filter, wherein the shielding member is disposed so as to be close to the cores at least between the adjacent cores, and is grounded. The line filter according to claim 1, further comprising an insulating pressing member wound integrally around an outer peripheral portion of each core and the shielding member. The plurality of inductors on the first conductive line include a first inductor composed of a first core and a first winding, and a second inductor composed of a second core and a second winding. And
And a third inductor and a fourth inductor connected in series with each other on the second conductive line,
The third inductor includes a third winding wound around the first core together with the first winding, and the fourth inductor includes the second core together with the second winding. Including a fourth winding wound around
The first core and the second core are arranged close to each other;
The said shielding member is arrange | positioned so that it may adjoin to the said 1st and 2nd core at least between the said 1st core and the said 2nd core, and is earth | grounded. The line filter according to 1 or 2. A fifth inductor including a fifth winding, one end of which is connected in the middle of the first winding;
A sixth inductor including a sixth winding, one end of which is connected in the middle of the third winding;
The line filter according to claim 3, wherein the fifth and sixth windings are wound around the first core together with the first and third windings. A seventh inductor including a seventh winding, one end of which is connected in the middle of the first winding;
An eighth inductor including an eighth winding, one end of which is connected in the middle of the third winding;
The line filter according to claim 4, wherein the seventh and eighth windings are wound around the second core together with the second and fourth windings.

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