JP6765553B1 - Noise filter - Google Patents

Abstract

Input terminals (8) and output terminals (9) arranged separately on both sides of the circuit board (2) and circuit board (2), one end is connected to each of the input terminals (8), and the other ends are connected to each other. A line capacitor (3) connected to the neutral point, a line capacitor (4) with one end connected to each of the output terminals (9) and the other ends connected to the neutral point, and one end input. A choke coil (5) having a coil (52) connected to each of the terminals (8) and the other end of the output terminals (9) connected to an output terminal located diagonally opposite to the input terminal in the terminal arrangement. , Was configured to be provided.

Description

The present application relates to a noise filter.

A noise filter is inserted between the AC power supply and the load device in order to reduce noise entering the load device from the power supply and noise leaking from the load device to the power supply. In the noise filter, filter components such as a common mode choke coil and a capacitor are mounted on a circuit board or a metal mounting plate (see, for example, Patent Document 1).

Square root extraction No. 6-38224 (paragraphs 0011 to 0016, FIGS. 1 to 3)

However, in general noise filters including the disclosure in Patent Document 1, the output side capacitor and the output side connected to the load device are used with respect to the input side capacitor and the input side wiring connected to the AC power supply. Are placed close to each other and facing each other. Furthermore, since the input terminal connected to the AC power supply and the output terminal connected to the load device are arranged in the same phase order, the directions of the normal mode noise currents flowing through the line capacitors on the input side and the output side are in the same direction. Become.

Therefore, the magnetic field generated by the current loop formed by the input side capacitor and the wiring and the magnetic field generated by the current loop formed by the output side capacitor and the wiring are strengthened. As a result, there is a problem that the noise propagation path is formed without passing through the wiring member due to the magnetic coupling between the current loop on the input side and the current loop on the output side, and the noise reduction effect is deteriorated.

The present application discloses a technique for solving the above-mentioned problems, and an object of the present application is to obtain a noise filter having an excellent noise reduction effect.

The noise filter disclosed in the present application corresponds to a circuit board, three input terminals arranged at one end of the circuit board, and the three input terminals, and is arranged at the other end facing the one end. Three output terminals, one end connected to each of the three input terminals, the other ends connected to a neutral point, a plurality of input side line capacitors, one end connected to each of the three output terminals, and the like. A plurality of output side line capacitors whose ends are connected to neutral points and a ring-shaped core are wound along the circumferential direction, one end is connected to each of the three input terminals, and the other end is the above 3. Among the three output terminals, a choke coil having three sets of coils connected to the output terminals located diagonally to the input terminals in the arrangement is provided, and one of the three input terminals on the outer side in the arrangement is provided. The first input terminal located at and the first output terminal located diagonally to the first input terminal are close to the first input terminal in the direction in which both ends of the three sets of coils are in the direction along the arrangement. It is connected by a lead wire drawn out in parallel with the opposite direction from both ends of the first coil arranged separately on the side and the side close to the first output terminal in the direction along the arrangement. It is a feature.

According to the noise filter disclosed in the present application, the directions of the normal mode noise currents flowing through the line capacitors on the input side and the output side are opposite to each other, so that the generation of the noise propagation path is suppressed and the noise reduction effect is excellent. A noise filter can be obtained.

It is a partial transmission perspective view which shows the structure of the noise filter which concerns on Embodiment 1. FIG. It is a circuit diagram which shows the circuit structure of the noise filter which concerns on Embodiment 1. FIG. 3A and 3B are a partially transmitted top view and a partially transmitted bottom view of the noise filter according to the first embodiment, respectively. It is a figure which shows the noise filter which concerns on Embodiment 1, the noise filter which concerns on a comparative example, and the normal mode noise attenuation characteristics of each. 5A and 5B are a partially transmitted top view and a partially transmitted bottom view of the noise filter according to the second embodiment, respectively. It is a circuit diagram which shows the circuit structure of the noise filter which concerns on Embodiment 3. FIG. It is the partial transmission bottom view of the noise filter which concerns on Embodiment 3. FIG. 8A and 8B are a partially transmitted top view and a partially transmitted bottom view of the noise filter according to the fourth embodiment, respectively. It is the partial transmission top view of the noise filter which concerns on Embodiment 5. FIG. 10A and 10B are a top view and a bottom view of the noise filter according to the sixth embodiment, respectively.

Embodiment 1.
1 to 4 are for explaining the noise filter according to the first embodiment, FIG. 1 is a partially transmitted perspective view through which a circuit board portion showing a configuration of the noise filter is transmitted, and FIG. 2 is a noise filter. It is a circuit diagram which shows the circuit structure of, and the setting area of a part of a spatial arrangement. Further, FIG. 3 shows a partially transparent top view (corresponding to arrow A in FIG. 1: FIG. 3A) in which the circuit board portion of the noise filter is transmitted when the side on which the common mode choke coil is mounted is the upper surface. It is a partially transparent bottom view (corresponding to arrow view B in FIG. 1: FIG. 3B). Then, FIG. 4 shows the frequency characteristics (normal mode noise attenuation characteristics) of the attenuation amount for each of the noise filter according to the first embodiment and the noise filter according to the comparative example, and a semi-log of the frequency and the attenuation amount. It is a figure shown by a graph.

As shown in FIG. 2, the noise filter 1 according to the first embodiment is connected to the common mode choke coil 5 with the input terminal 8 connected to the AC power supply and the output terminal 9 connected to the load device. , Each of which is provided with line capacitors 3 and 4. For example, on the AC power supply side, input terminals 8a, 8b, and 8c corresponding to each phase (U, V, W) are installed, and each of the input terminals 8 and the common mode choke coil 5 (strictly speaking, the coil 52 (strictly speaking) FIG. 3A)) is connected by wiring. Then, one end of the line capacitor 3a, 3b, 3c is connected to each of the wirings connected to the input terminals 8a, 8b, 8c, and the other ends of the line capacitors 3 are connected to the neutral point.

Similarly, output terminals 9a, 9b, 9c corresponding to each phase (u, v, w) are installed on the load device side, and each of the output terminals 9 and the common mode choke coil 5 (coil 52) are wired. Connected by. Then, one end of the line capacitor 4a, 4b, 4c is connected to each of the wires connected to the output terminals 9a, 9b, 9c, and the other ends of the line capacitors 4 are connected to the neutral point. Then, as shown in FIGS. 1 and 3, the input terminals 8a, 8b, and 8c are arranged on one end side of the circuit board 2 at intervals, and the output terminals 9a, 9b, and 9c are connected to other than the circuit board 2. Arranged at intervals on the end side.

Then, the common mode choke coil 5 is arranged on the upper surface 2fa which is one surface of the circuit board 2 such as a printed circuit board having the printed wiring, and the line capacitors 3 and 4 are arranged on the lower surface 2fb side which is the opposite surface of the upper surface 2fa. I tried to do it. As a result, the mounting area of the wiring member related to the noise filter can be reduced, and the noise filter 1 can be miniaturized.

As shown in FIG. 3A, the common mode choke coil 5 is composed of, for example, a toroidal core 51 (or a ring core) and a coil 52 wound around the toroidal core 51, and the coil end is printed wiring of the circuit board 2. Is directly connected to. In this case, if the coil 52 constituting the common mode choke coil 5 is configured with a coil having a large wire diameter, the rigidity of the coil 52 is high, so that the wound toroidal core 51 is not supported by a support or fixed with resin. Even if it is arranged on the circuit board 2. Strictly speaking, the common mode choke coil 5 is composed of two coils whose winding directions are reversed for each phase, but in the description of the present application, it is simply referred to as a coil 52 for simplification.

However, the configurations up to this point are the same as the basic configurations as a general noise filter, including Patent Document 1. On the other hand, in the noise filter 1 according to each embodiment of the present application, the phase order of the wiring member (region Ro) on the load device side is different from that of the wiring member (region Rs) on the AC power supply side shown in FIG. The space was arranged like this. Specifically, the phase order (U, V, W) of the input terminals 8a, 8b, 8c connected to the AC power supply and the phase order (u, v, w) of the output terminals 9a, 9b, 9c connected to the load device. ) Is reversed, and the coil 52 is pulled out so as to connect the terminals located diagonally to each other.

The line capacitors 3 and 4 work to return the normal mode noise that invades from the AC power supply or leaks from the load device to the noise source. As described above, in the present application, the phase order of the input terminals 8a, 8b, 8c connected to the AC power supply and the phase order of the output terminals 9a, 9b, 9c connected to the load device are reversed. The AC power supply and the load device are connected to the noise filter 1. Then, with respect to the normal mode noise received from the AC power supply or the load device, the directions of the normal mode noise current flowing through the line capacitors 3a, 3b and 3c and the normal mode noise current flowing through the line capacitors 4a, 4b and 4c are different. The directions are opposite to each other.

As a result, the magnetic field generated in the current loop of the normal mode noise flowing through the line capacitors 3a, 3b, 3c on the AC power supply side and the current loop of the normal mode noise flowing through the line capacitors 4a, 4b, 4c on the load device side The generated magnetic fields cancel each other out. Therefore, the generation of the noise propagation path that does not pass through the wiring member (filter member) constituting the noise filter 1 is suppressed, and the deterioration of the normal mode noise attenuation characteristic is suppressed.

Here, using the same filter member as the noise filter 1 of the present application, a noise filter different only in that the phase order of the AC power supply side and the load device side is aligned is created as a comparative example, and the noise filter 1 of the present application and the normal mode noise are created. The damping characteristics were compared. As a result, as shown in FIG. 4, the normal mode noise attenuation characteristic P1 (solid line) in the noise filter 1 of the present application is 0.1 more than the normal mode noise attenuation characteristic PC (broken line) of the noise filter of the comparative example. The amount of attenuation is low in all frequency bands of ~ 20 MHz. That is, it was confirmed that the noise filter 1 of the present application has better normal mode noise attenuation characteristics than the general noise filter arranged in the same phase order.

In the present application, the phase order of the input terminals 8a, 8b, 8c connected to the AC power supply and the phase order of the output terminals 9a, 9b, 9c connected to the load device are arranged so as to be reversed in terms of spatial arrangement. That is, the input terminals 8 and the output terminals 9 located diagonally are connected by the coil 52 so that the phases of the line capacitors 4 on the load device side facing each of the line capacitors 3 on the AC power supply side are different. As a result, the directions of the normal mode noise currents flowing through the line capacitors 3 on the AC power supply side and the line capacitors 4 on the load device side, which are close to each other, are opposite to each other, and the magnetic fields generated in the surroundings cancel each other out. As a result, the generation of a noise propagation path that does not pass through the filter member of the noise filter 1 is suppressed, and a noise reduction effect that has never existed in the past can be exhibited.

In the first embodiment, a three-phase noise filter inserted and connected between the three-phase AC power supply and the three-phase load device is shown as an example, but the present invention is not limited to this, and a three-phase four-wire system may be used. Further, for example, a single-phase noise filter that is inserted and connected between the single-phase AC power supply and the single-phase load device may be used, and the same effect can be obtained by connecting diagonally located terminals regardless of the phase wire type. Has. In each of the following embodiments, the three-phase noise filter will be described as an example as in the first embodiment, but the noise reduction effect can be achieved regardless of the phase line type.

Further, in the noise filter 1 according to the first embodiment including the second to fifth embodiments described later, the line capacitor 3 is placed on the opposite side (lower surface 2fb) of the mounting surface (upper surface 2fa) of the common mode choke coil 5. 4 was implemented. As a result, the mounting area is reduced, and it is possible to meet the demand for miniaturization. At this time, as the size is reduced, the distance between the line capacitor 3 and the line capacitor 4 becomes narrower, but noise can be reduced by suppressing the generation of the noise propagation path, and both miniaturization and noise reduction can be achieved at the same time. Can be made to.

Embodiment 2.
In the first embodiment, an example in which capacitors having different phases are arranged so as to face each other in the same direction on the power supply side and the load side has been described. In the present embodiment, an example in which the direction of the interphase capacitor on the load side is set according to the coil winding state of the common mode choke coil will be described.

5A and 5B are a partially transparent top view (corresponding to arrow A in FIG. 1) and a partially transmitted bottom view (arrow view in FIG. 1) in which the circuit board portion of the noise filter according to the second embodiment is transmitted, respectively. Corresponds to B). The configuration other than the portion related to the direction of the line capacitor on the load side of the noise filter according to the second embodiment is the same as the configuration described in the first embodiment, and the circuit diagram of FIG. 2 is incorporated. ..

As shown in FIG. 5, the noise filter 1 according to the second embodiment has the direction of the line capacitor 4 on the load device side in the region Rb of the toroidal core 51 in which the coil 52 of the common mode choke coil 5 is not wound. It is set according to the position. As shown in FIG. 5A, the common mode choke coil 5 is wound with coils 52 corresponding to each phase (Uu, Vv, Ww) at intervals, so that the toroidal core 51 A region Rb in which the coil 52 is not wound is generated in the circumferential direction. On the other hand, as shown in FIG. 5B, each line-to-line capacitor 4 has a columnar shape in which electrodes 43 and 44 are arranged on both end surfaces, and a line D4c connecting both electrodes 43 and 44 equal to the direction of displacement current is a mounting surface (lower surface 2fb). ) Is implemented so as to be parallel.

At this time, the common mode choke coil 5 and the line capacitors 3 and 4 are mounted on opposite sides of the circuit board 2, but the region Rb existing at the position closest to the line capacitors 3 and 4 is. This is the region Rb closest to the line capacitor 4 on the load device side. Therefore, the line capacitor 4 is mounted so that the tangent Lt (FIG. 5A) with respect to the midpoint Pm on the outer peripheral surface of the nearest region Rb and the line D4c (FIG. 5B) connecting the electrodes 43 and 44 are parallel to each other. The orientation on the surface (2fb) was set. In the line capacitor 4, the displacement current flows along the line D4c connecting one electrode 43 on both end faces to the other electrode 44, so that the direction of the displacement current and the tangent line Lt are parallel.

Of the toroidal core 51 of the common mode choke coil 5, a leakage magnetic field is generated from the region Rb where the coil 52 is not wound in the same direction as the tangent Lt of the midpoint Pm of the outer peripheral surface. On the other hand, a magnetic field in the right-handed screw direction is concentrically generated around the displacement current flowing in the direction of the line D4c between the electrodes on both end faces of the line capacitor 4. At this time, if the tangent line Lt and the line D4c are parallel, the leakage magnetic field generated from the common mode choke coil 5 and the magnetic field generated around the displacement current between the electrodes 43 and 44 of the line capacitor 4 are interlinking. become. Therefore, it is possible to suppress deterioration of the noise reduction effect due to interference between the leakage magnetic field generated from the common mode choke coil 5 and the magnetic field generated by the displacement current between the electrodes of the line capacitor 4.

In the second embodiment, the line capacitor 4 on the load device side is parallel to the tangent Lt with respect to the midpoint Pm on the outer peripheral surface of the nearest region Rb so that the line D4c connecting the electrodes 43 and 44 is parallel. An example of implementation is shown, but this is not the case. For example, when the region Rb is located in the immediate vicinity of the line capacitor 3 on the AC power supply side, the line capacitor 3 is arranged so that the lines connecting the electrodes formed on both end faces of the line capacitor 3 are parallel to the tangent Lt. The orientation may be set. Alternatively, depending on the arrangement of the region Rb, both the line capacitor 3 and the line capacitor 4 may be parallel to the tangent Lt.

Embodiment 3.
In the third embodiment, an example in which the line-to-ground capacitor is added to the neutral connection point between the line-line capacitors will be described with respect to the line-to-ground capacitor on the load device side. 6 and 7 are for explaining the noise filter according to the third embodiment, FIG. 6 is a circuit diagram showing a circuit configuration of the noise filter and a setting area of a part of the spatial arrangement, and FIG. 7 is a circuit diagram. It is a partial transmission top view which transmitted the circuit board portion of the noise filter corresponding to the arrow view A of FIG. The configuration other than the portion related to the installation of the ground-to-ground capacitor on the load side of the noise filter according to the third embodiment is the same as the configuration described in the first embodiment.

As shown in FIGS. 6 and 7, the noise filter 1 according to the third embodiment is grounded between the neutral connection point between the other ends of the line capacitors 4a, 4b, and 4c on the load device side and the ground 7. An interim capacitor 6 is provided (the ground terminal 6g is shown in FIG. 7). The ground-to-ground capacitor 6 works to release the common mode noise current to the ground 7. Therefore, the common mode noise invading the load device can be reduced by passing the common mode noise current invading from the AC power supply to the ground 7 by the ground-to-ground capacitor 6. Further, by passing the common mode noise current flowing out from the load device to the ground 7, it is possible to reduce the common mode noise flowing out to the AC power supply.

In the third embodiment, an example in which one ground-to-ground capacitor 6 is installed is shown, but a ground-to-ground capacitor having a capacitance of one-third between each phase on the load device side and the ground 7 is used. Since it operates in the same manner as when it is installed, the number of parts can be reduced and the noise filter 1 can be downsized. Further, since the line capacitors 4a, 4b, and 4c on the load device side for normal mode noise countermeasures are only the capacitances connected for each line, even if there is a ground-to-ground capacitor 6 for common mode noise countermeasures. The capacitance of the line capacitors 4a, 4b, and 4c does not change.

Here, the setting of the capacitance of the ground-to-ground capacitor 6 in the third embodiment will be described. Assuming that the combined capacitance of the line capacitors 4a, 4b, 4c and the ground capacitor 6 on the load device side is C_XY, the equation (1) holds between the leakage current I, the input voltage V, and the frequency f of the input voltage. ..
C_XY = I / (2πfV) ・ ・ ・ (1)

That is, the combined capacitance C_XY of the line capacitors 4a, 4b, 4c and the ground capacitor 6 on the load device side is determined by the specified value of the leakage current I, which differs for each load device, and the input voltage V and the frequency f of the input voltage. Therefore, the capacitance of the ground-to-ground capacitor 6 is set so that the combined capacitance C_XY with the line capacitors 4a, 4b, and 4c on the load device side satisfies the equation (1).

In the third embodiment, an example in which the ground-to-ground capacitor 6 is installed between the line capacitors 4a, 4b, 4c and the ground 7 on the load device side is not limited to this. For example, a ground-to-ground capacitor may be installed between the line capacitors 3a, 3b, 3c on the AC power supply side and the ground 7, or both may be installed. Also, since the line capacitors 3a, 3b, and 3c on the AC power supply side for normal mode noise countermeasures have only the capacitance connected for each line, AC even if there is an AC capacitor for common mode noise countermeasures. The capacitance of the line capacitors 3a, 3b, and 3c on the power supply side does not change.

Embodiment 4.
In the third embodiment, an example in which the ground-to-ground capacitor is arranged between the neutral connection point between the line-through capacitors and the ground is shown. In the fourth embodiment, an example in which the direction of the capacitor to ground is set according to the coil winding state of the common mode choke coil will be further described.

8A and 8B are a partially transparent top view (corresponding to arrow A in FIG. 1) and a partially transmitted bottom view (arrow view in FIG. 1) in which the circuit board portion of the noise filter according to the fourth embodiment is transmitted, respectively. Corresponds to B). The configuration other than the portion related to the orientation of the ground-to-ground capacitor of the noise filter according to the fourth embodiment is the same as the configuration described in the third embodiment, and the circuit diagram of FIG. 6 is incorporated.

As shown in FIG. 8, the noise filter 1 according to the fourth embodiment sets the direction of the ground-to-ground capacitor 6 according to the position of the region Rb of the toroidal core 51 in which the coil 52 of the common mode choke coil 5 is not wound. It is set. The region Rb in the common mode choke coil 5 in which the coil 52 is not wound in the circumferential direction is the same as in the second embodiment. On the other hand, the ground-to-ground capacitor 6 has a columnar shape in which electrodes 63 and 64 are arranged on both end surfaces, and the wire D6c connecting both electrodes 63 and 64 is a mounting surface, as in the line capacitor 4 described in the second embodiment. It is mounted so as to be parallel to (lower surface 2fb).

At this time, the region Rb existing at the position closest to the ground-to-ground capacitor 6 is the region Rb on the load device side. Therefore, the ground-to-ground capacitor 6 is oriented on the mounting surface (2fb) so that the tangent line Lt with respect to the midpoint Pm on the outer peripheral surface of the nearest region Rb and the line D6c connecting both electrodes 63 and 64 are parallel. It was set. In the ground-to-ground capacitor 6, as in the line capacitor 4 described in the second embodiment, the displacement current flows along the line D6c connecting one electrode 63 on both end faces to the other electrode 64, so that the direction of the displacement current And the tangent line Lt become parallel.

Of the toroidal core 51 of the common mode choke coil 5, a leakage magnetic field is generated from the region Rb where the coil 52 is not wound in the same direction as the tangent Lt of the midpoint Pm of the outer peripheral surface. On the other hand, a magnetic field in the right-handed screw direction is concentrically generated around the displacement current flowing in the direction of the line D6c connecting the electrodes 63 and 64 between the electrodes on both end faces of the ground-to-ground capacitor 6. At this time, if the tangent line Lt and the line D6c are parallel, the leakage magnetic field generated from the common mode choke coil 5 and the magnetic field generated around the displacement current between the electrodes 63 and 64 of the ground-to-ground capacitor 6 are interlinking. become. Therefore, it is possible to suppress deterioration of the noise reduction effect due to interference between the leakage magnetic field generated from the common mode choke coil 5 and the magnetic field generated by the displacement current between the electrodes of the ground-to-ground capacitor 6.

In the fourth embodiment, the line D6c connecting the electrodes 63 and 64 of the ground-to-ground capacitor 6 arranged between the line capacitor 4c on the load device side and the ground 7 is the region Rb of the common mode choke coil 5. An example of being parallel to the tangent line Lt with respect to the midpoint Pm is shown, but this is not the case. For example, when the region Rb is located in the immediate vicinity of the line capacitor 3 on the AC power supply side and the line capacitor 3 is provided on the side of the line capacitor 3, the line connecting the electrodes formed on both end faces thereof is tangent Lt. The orientation of the ground-to-ground capacitor may be set so that it is parallel. Alternatively, depending on the arrangement of the region Rb, both the line-to-ground capacitor 3 and the line-to-ground capacitor on the line-to-ground capacitor 4 side may be parallel to the tangent line Lt. In some cases, as described in the second embodiment, the line connecting the electrodes of the line capacitors 3 and 4 may also be parallel to the tangent line Lt.

Embodiment 5.
In each of the above embodiments, the pin shape is assumed as the input terminal and the output terminal, but the terminal form is not limited to this. In the third embodiment, an example in which a screw-fastened structure is formed on the input terminal and the output terminal will be described. FIG. 9 is a partially transparent top view corresponding to the arrow A in FIG. 1 in which the circuit board portion of the noise filter according to the fifth embodiment is transmitted. The configuration other than the input terminal and the load terminal of the noise filter according to the fifth embodiment is the same as the configuration described in each of the above embodiments.

As shown in FIG. 9, the noise filter 1 according to the fifth embodiment has input terminals 8a, 8b, 8c and output terminals 9a, 9b, 9c with respect to FIG. 3A used in the description of the first embodiment. A screw portion 81 and a screw portion 91 are provided on each of them. More specifically, the screw portions 81 and 91 are opened at least on the upper surface 2fa side and provided with screw holes that can be tightened with screws. Further, the lower surface 2fb side has a region (not shown) for soldering.

Even with such a structure, the same effect as that of the noise filter 1 shown in each of the above embodiments can be obtained. With this configuration, it is possible to facilitate the connection of the common mode choke coil 5 to the circuit board 2 and the connection of the AC power supply and the load device to the noise filter 1. In the fifth embodiment, the input terminals 8a, 8b, 8c and the output terminals 9a, 9b, 9c are provided on the arrangement surface (upper surface 2fa) side of the common mode choke coil 5, but the present invention is not limited to this. , May be provided on the opposite surface (lower surface 2fb) side. Further, the hole is not limited to the screw hole, and may be a press-fit terminal, a connection port for the press-fit terminal, or a quick-connect terminal that can be connected simply by inserting an electric wire.

Embodiment 6.
In each of the above embodiments, in order to reduce the mounting area, an example in which the common mode choke coil and the line capacitor are arranged on the opposite surface of the circuit board has been shown, but the present invention is not limited to this. In the sixth embodiment, an example in which the common mode choke coil and the line capacitor are mounted in the same plane of the circuit board will be described. 10A and 10B are a top view (corresponding to the arrow A in FIG. 1) and a bottom view (corresponding to the arrow B in FIG. 1) of the noise filter according to the sixth embodiment, respectively. The configuration other than the portion related to the member arrangement of the noise filter according to the sixth embodiment is the same as that of the other embodiments. For example, the circuit configuration is shown in FIG. 2 described in the first embodiment. Is similar to.

In the noise filter 1 according to the sixth embodiment, as shown in FIG. 10, the common mode choke coil 5 and the line capacitors 3 and 4 are arranged on the same surface (upper surface 2fa) of the circuit board 2. Then, the wiring (wiring pattern) to the input terminal 8 and the output terminal 9 has the following configuration different from that of the first embodiment.

As a wiring pattern on the input terminal 8 side, as shown in FIG. 10A, a pattern 82 and a pattern 83 arranged for each phase and a pattern 84 shared by each phase are formed on the upper surface 2fa side. Each phase of the common mode choke coil 5 and one end of each of the line capacitors 3a, 3b, and 3c are connected to the pattern 83, and the pattern 84 is a neutral point, and each other end of the line capacitor 3 is collectively set. It is connected. Then, on the lower surface 2fb side, as shown in FIG. 10B, a pattern 85 is formed which is arranged for each phase and is electrically connected to each of the pattern 82 and the pattern 83 on the upper surface 2fa side through the circuit board 2. Has been done.

Similarly, as a wiring pattern on the output terminal 9 side, a pattern 92 and a pattern 93 arranged for each phase and a pattern 94 shared by each phase are formed on the upper surface 2fa side. In the pattern 93, each phase of the common mode choke coil 5 and one end of each of the line capacitors 4a, 4b, and 4c are connected, and in the pattern 94, each other end of the line capacitor 4 is collectively set as a neutral point. It is connected. Then, on the lower surface 2fb side, a pattern 95 is formed which is arranged for each phase and is electrically connected to each of the pattern 92 and the pattern 93 on the upper surface 2fa side through the circuit board 2.

As a result, the spatial arrangement of the line capacitors 3 and 4 with respect to the common mode choke coil 5 is different from that of the noise filter 1 of the first embodiment, but the circuit as the noise filter 1 is the same as that of FIG. It is equivalent on the circuit. Then, since the input terminal 8 and the output terminal 9 located diagonally are connected by the coil 52, the line-to-line capacitor 4 facing the line-to-line capacitor 3 has the same phase order as the noise filter 1 of the first embodiment. It's reversed.

Therefore, it is generated by the magnetic field generated in the current loop of the normal mode noise flowing through the line capacitors 3a, 3b, 3c on the AC power supply side and the current loop of the normal mode noise flowing through the line capacitors 4a, 4b, 4c on the load device side. The magnetic fields that form cancel each other out. As a result, as in the first embodiment, the generation of the noise propagation path that does not pass through the wiring member (filter member) constituting the noise filter 1 is suppressed, and the deterioration of the normal mode noise attenuation characteristic is suppressed.

Although various exemplary embodiments and examples are described in the present application, the various features, embodiments, and functions described in one or more embodiments are specific embodiments. It is not limited to the application of, but can be applied to the embodiment alone or in various combinations. Therefore, innumerable variations not illustrated are envisioned within the scope of the techniques disclosed herein. For example, it is assumed that at least one component is modified, added or omitted, and further, at least one component is extracted and combined with the components of other embodiments.

For example, in the sixth embodiment, the configuration in which the common mode choke coil 5 and the line capacitors 3 and 4 are arranged on one surface is not limited to the first embodiment and is applied to the configurations described in the second to fifth embodiments. Even in this case, the same noise reduction effect as in each embodiment can be obtained. Further, an example in which the common mode choke coil 5 is used as the choke coil is shown. It is not limited to this. Even in the choke coil including the normal mode choke coil, the generation of the noise propagation path that does not pass through the wiring member (filter member) is suppressed, and the deterioration of the normal mode noise attenuation characteristic is suppressed.

As described above, according to the noise filter 1 according to each embodiment, a plurality of inputs arranged at one end of the circuit board 2 corresponding to the phase line type of the circuit board 2 and the input power supply (AC power supply). A plurality of output terminals 9 corresponding to the terminals 8 and a plurality of input terminals 8 and arranged at the other end of the circuit board 2 facing the other end, one end of which is connected to each of the plurality of input terminals 8 and the other ends of each other. Is connected to each of the plurality of input-side line capacitors (line-line capacitors 3) connected to the neutral point, one end is connected to each of the plurality of output terminals 9, and the other ends are connected to the neutral point. The line-to-line capacitor (line-to-line capacitor 4) on the side and the input terminals 8a and 8b in the (terminal) arrangement of the plurality of output terminals 9 having one end connected to each of the plurality of input terminals 8 and the other end being connected to each of the plurality of input terminals 8. , 8c Diagonally located (the order of arrangement is reversed) Common mode choke coil 5 having a plurality of coils 52 connected to output terminals 9a, 9b, 9c (choke coil including normal mode choke coil) Since the normal mode noise currents flowing through the line capacitor 3 on the input side and the line capacitor 4 on the output side are in opposite directions to each other, a noise propagation path is generated without passing through the filter member. Is suppressed, and a noise filter 1 having an excellent noise reduction effect can be obtained.

In particular, the plurality of input-side line capacitors 3 and the plurality of output-side line-line capacitors 4 are on the opposite side (for example, the upper surface 2fa) of the circuit board 2 on which the common mode choke coil 5 is mounted. If it is mounted on the lower surface 2fb), the mounting area can be reduced, and it is possible to meet the demand for miniaturization. Further, with the miniaturization, even if the distance between the line capacitor 3 and the line capacitor 4 becomes narrower, the generation of the noise propagation path is suppressed, so that the noise can be reduced, and both the miniaturization and the noise reduction can be achieved at the same time. be able to.

Further, at least one of the plurality of input-side line capacitors 3 and the plurality of output-side line-line capacitors 4 has a columnar shape in which electrodes (for example, electrodes 43 and 44) are arranged on both end faces, and both ends. The wire connecting the surface electrodes (for example, wire D4c) is on the outer peripheral surface of the ring-shaped core (toroidal core 51) constituting the common mode choke coil 5 in the region Rb where the coil 52 is not wound in the circumferential direction. If arranged so as to be parallel to the tangent line Lt with respect to the midpoint Pm, the leakage magnetic field generated from the common mode choke coil 5 and the magnetic field generated around the displacement current between the electrodes of the line capacitor 4 or the line capacitor 3 Becomes a chain relationship. Therefore, it is possible to suppress deterioration of the noise reduction effect due to interference between the leakage magnetic field generated from the common mode choke coil 5 and the magnetic field generated by the displacement current between the electrodes of the line capacitor 4 or the line capacitor 3.

Further, one end is grounded, and the other end is provided with a ground-to-ground capacitor 6 connected to the other ends connected to the neutral points of a plurality of input-side line capacitors 3 or a plurality of output-side line capacitors 4. Then, the ground-to-ground capacitor 6 makes it possible to reduce the common mode noise invading the load device by passing the common mode noise current invading from the AC power supply to the ground 7. Alternatively, by passing the common mode noise current flowing out of the load device to the ground 7, it is possible to reduce the common mode noise flowing out to the AC power supply.

Further, the ground-to-ground capacitor 6 has a columnar shape in which electrodes 63 and 64 are arranged on both end faces, and a ring-shaped core (toroidal) in which a line D6c connecting the electrodes 63 and 64 on both end faces constitutes a common mode choke coil 5. If the core 51) is arranged so as to be parallel to the tangent line Lt with respect to the midpoint Pm on the outer peripheral surface of the region Rb in which the coil 52 is not wound in the circumferential direction, the leakage magnetic field generated from the common mode choke coil 5 and the ground are ground. It is possible to suppress deterioration of the noise reduction effect due to mutual interference of magnetic fields generated by the displacement current between the electrodes of the inter-capacitor 6.

1: Noise filter, 2: Circuit board, 2fa: Top surface, 2fb: Bottom surface, 3, 3a, 3b, 3c: Line capacitor (input side line capacitor), 4, 4a, 4b, 4c: Line capacitor (output side line) Inter-capacitor), 5: Common mode choke coil (choke coil), 51: Toroidal core, 52: Coil, 8, 8a, 8b, 8c: Input terminal, 9, 9a, 9b, 9c: Output terminal, 6: Between ground Capacitor, 6g: ground terminal, 7: ground, D4c, D6c: wire (connecting between electrodes), Lt: tangent wire, Pm: midpoint, Rb: region.

Claims (8)

With the circuit board
Three input terminals arranged at one end of the circuit board,
Three output terminals corresponding to the three input terminals and arranged at the other end facing the one end,
A plurality of input side line capacitors, one end of which is connected to each of the three input terminals and the other end of which is connected to a neutral point.
A plurality of output side line capacitors having one end connected to each of the three output terminals and the other ends connected to a neutral point, and
An output that is wound around a ring-shaped core along the circumferential direction, one end of which is connected to each of the three input terminals, and the other end of the three output terminals located diagonally to the input terminal in the array. A choke coil, which has three sets of coils connected to the terminals,
Of the three input terminals, the first input terminal located on the outer side of the array and the first output terminal located diagonally to the first input terminal have both ends of the three sets of coils. closer to the first input terminal in the direction along the array, the direction of each of the opposing the end portions of the first coil which is arranged separately on the side closer to the first output terminal in a direction along the array A noise filter characterized by being connected by lead wires drawn in parallel. A third coil that connects a third input terminal located on the outer other side of the arrangement and a third output terminal located diagonally to the third input terminal, and the remaining second input terminal and second output terminal. noise filter according to claim 1 second coil, which is characterized in that by crossing the respective lead lines in a remote space from the circuit board to be connected and. The intersection of the lead wire includes a lead wire drawn out toward the side of the end portion closer to the third output terminal in a direction along the arrangement of the second coil to the second output terminal, said third coil noise filter according to claim 2, characterized in that it is more formed on the lead line of drawn toward the third output terminal from the end located in the middle portion in the direction along the array of. The noise filter according to any one of claims 1 to 3, wherein a common mode choke coil is used as the choke coil. Claims 1 to 4 are characterized in that the plurality of input side line capacitors and the plurality of output side line capacitors are mounted on a surface of the circuit board opposite to the surface on which the choke coil is mounted. The noise filter according to any one of the above items. At least one of the plurality of input side line capacitors and the plurality of output side line capacitors is
It forms a columnar shape in which electrodes are arranged on both end faces, and the line connecting the electrodes on both end faces is parallel to the tangent line to the midpoint on the outer peripheral surface of the region in which the coil is not wound in the circumferential direction. The noise filter according to any one of claims 1 to 5, wherein the noise filter is arranged in such a manner. One end is grounded, and the other end is provided with a ground-to-ground capacitor connected to the other ends connected to the neutral points of the plurality of input side line capacitors or the plurality of output side line capacitors. The noise filter according to any one of claims 1 to 6. The ground-to-ground capacitor has a columnar shape in which electrodes are arranged on both end faces.
The claim is characterized in that the lines connecting the electrodes on both end faces are arranged so as to be parallel to the tangent line to the midpoint on the outer peripheral surface of the region where the coil is not wound in the circumferential direction in the core. Item 7. The noise filter according to item 7.

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