JP2010219193A - Inductance element, and noise filter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a noise filter which is improved in noise attenuation effect without having its structure made complicated, and to provide an inductance element used therefor. <P>SOLUTION: The inductance element includes first and second AC lines (5a, 5b) each having one end connected to a commercial power source and the other end connected to the side of a load device, and a core body (1) wherein a core (2) made of a magnetic material and wound with the AC lines and a shield core (3) in a spherical shell shape and enclosing the core are formed in one body, the first and second AC lines being wound around the core of the core body in mutually opposite directions. The inductance element is magnetically shielded by the shield core, so the inductance element is not influenced by undesired external magnetic flux to improve the noise attenuation effect. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an inductance element and a noise filter used for a noise filter.

  Electrical devices with built-in motors such as air conditioners and washing machines are widely used. In these electric appliances, commercial power is temporarily converted into direct current by a converter, and further converted into alternating current using an inverter and supplied to the motor. Switching elements constituting the inverter are switching-controlled at high speed by a pulse width modulation signal. In such power converters including converters and inverters, electromagnetic interference noise is generated by high-speed switching operation, and the generated electromagnetic interference noise flows through the power line and ground to cause other devices to cause malfunction. It becomes. In order to remove such electromagnetic interference noise, a noise filter is provided between the commercial power supply and the load device.

  As a noise filter, a noise filter using a common mode choke coil in which a pair of windings are wound around an annular core is known (for example, see Patent Document 1). In this known inductance element, the outer peripheral surface of a toroidal core is covered with an insulating case, and two windings are wound around the entire surface of the insulating case. Further, in order to form a capacitive coupling between the two windings, a copper foil is attached, and a ground connection terminal connected to the copper foil is extended in parallel with the lead portions of the two windings.

JP 2008-205295 A

  When the above-described inductance element is used for a noise filter, although the noise attenuation effect is recognized, the attenuation amount is not sufficiently satisfied, and there is a strong demand for further improvement in noise attenuation performance. Furthermore, if the amount of attenuation is to be improved, it is necessary to increase the size of the magnetic core, and there is a disadvantage that the inductance element becomes larger. Furthermore, the known inductance element described above has a problem that the structure is complicated and the manufacturing cost is high because the copper foil is attached to capacitively couple the two windings.

  An object of the present invention is to realize a noise filter having an improved noise attenuation effect and an inductance element used therefor without complicating the structure.

An inductance element used in a noise filter connected between a commercial power source and a load device, one end of which is connected to the commercial power source and the other end is connected to the load device side; A core body formed of a magnetic material, around which the AC line is wound, and a core body integrally formed with a spherical shell-shaped shield core that surrounds the core core; The first and second AC wires are wound around the core core of the core body in an opposite direction to solve the problem by an inductance element.
Here, the “core core around which the AC line is wound” indicates that the AC line is wound around the core core. That is, “it” is “core core”. When the AC line is wound directly around the core core (Example 1) and when a separate bobbin is provided around the core core, the AC line is wound directly around the bobbin instead of the core core ( Example 2).

  In the inductance element, the first and second AC lines are wound in opposite directions around the core core to form first and second windings, and the first and second windings are formed. Solves the problem by an inductance element characterized by being magnetically shielded by the shield core.

  In the inductance element, the AC line is directly wound around a bobbin surrounding a core core, the bobbin includes a terminal and a plurality of legs, and is configured to be mountable on a substrate. Solve the problem.

  In the inductance element, the core body is constituted by two core members that are divided into two along a plane orthogonal to the axis of the core core to solve the problem.

  In the inductance element, at least one of the core members is formed with a flange parallel to a surface perpendicular to the axis of the core core, and is configured to be mountable on a substrate. The problem is solved by the inductance element.

  In the inductance element, the AC line is wound directly around a core core, and the inductance element has an external structure arranged outside the load device. .

  A noise filter connected between a commercial power source and a load device and including an inductance element and a capacitive element, wherein the inductance element has a first end connected to the commercial power source and the other end connected to the load device side. The first and second AC lines, a core core made of a magnetic material, around which the AC line is wound, and a spherical shell-shaped shield core surrounding the core core are integrally formed. And the first and second AC wires are wound around the core core of the core body in opposite directions to form first and second windings. The problem is solved by a noise filter characterized in that the first and second windings are magnetically shielded by the shield core.

  A clamp core that is connected to an AC power supply line and attenuates noise, and is composed of a first and second AC lines having one end connected to a commercial power supply and the other end connected to the load device side, and a magnetic material, The first and second alternating currents comprise a core core around which the AC line is wound, and a core body integrally formed with a spherical shell-shaped shield core surrounding the core core. Wires are wound around the core core of the core body in opposite directions to form first and second windings, and these first and second windings are magnetically shielded by the shield core. The problem is solved by a clamp core characterized by

  According to the present invention, a core body in which a core core around which a winding is wound and a spherical shell-shaped shield core surrounding the core core is integrated, and the core core is wound around the core core. Since an inductance element in which the wound winding is magnetically shielded is used, an excellent noise attenuating effect is exhibited that is hardly affected by the external magnetic flux. In particular, the noise level in the low frequency band around 200 kHz, which is difficult to remove with the conventional noise filter, can be considerably reduced.

  FIG. 1 is a view showing an example of an inductance element used in a noise filter according to a first embodiment of the present invention. FIG. 1A is a cross-sectional view taken along a plane including the axis of the core core, and FIG. ) Is a perspective view showing two core members apart. The inductance element according to the present invention has a core body 1 made of a magnetic material. As shown in FIG. 1B, the core body 1 has two core members 1a and 1b, and has a structure divided into two along a plane orthogonal to the core core. The core main body shown in FIG. 1A is formed by bonding the two core members 1a and 1b via an adhesive. As shown in FIG. 1A, the core body 1 has a structure in which a core core 2 and a spherical shell-shaped shield core 3 surrounding the entire core core 2 are integrally formed. In the shield core 3, two openings 4a and 4b are formed so as to face each other with the core core 2 interposed therebetween.

  A pair of AC wires 5 a and 5 b are wound around the core core 2. One ends of the AC lines 5a and 5b are connected to the commercial power supply side through the opening 4a, and the other ends are connected to the load device side through the opening 4b. FIG. 2 is a diagram showing the core body cut along a plane orthogonal to the core core, and shows the winding direction of the pair of AC wires 5a and 5b. The first AC line 5a is wound around the core core 2 in the clockwise direction to form the first winding 6a, and the second AC line 5b is counterclockwise around the core core. It is wound to form the second winding 6b. That is, the two AC wires are wound around the core core 2 in opposite directions.

  The inductance element according to the present invention is formed by a winding portion wound around a core core of an AC line and a core body, and the inductance element itself is magnetically shielded by a spherical shell-shaped shield core 3. Therefore, the magnetic flux generated by the current flowing through the two windings flows along the spherical shell-shaped shield core and does not leak to the outside. At the same time, the magnetic flux incident from the outside flows along the shield core and does not affect the winding. Therefore, since the magnetic flux generated by the inductance element does not leak to the outside and the external magnetic flux hardly penetrates into the inductance element, an inductance element that is not affected by an undesired external magnetic flux is realized.

  The core members 1a and 1b constituting the core body are manufactured by press-molding magnetic powder coated with an insulating coating, or a magnetic powder having a high magnetic permeability is mixed in an electrically insulating binder. It is manufactured by press-molding the mixed powder. As the ferromagnetic powder, for example, one selected from iron, iron silicide, permalloy (Fe-Ni), supermalloy (Fe-Ni-Mo), sendust, iron nitride, iron aluminum alloy, iron cobalt alloy, etc. Two or more kinds of magnetic metals can be used. Further, as an insulating material or an insulating binder for coating the ferromagnetic powder, an insulating material selected from various inorganic materials such as silicon oxide and organic materials is used. Specifically, for example, it is selected from silicon oxide, water glass, phenol resin, silicone resin, epoxy resin and the like.

  When assembling the inductance element shown in FIG. 1A, each AC line is wound around the core core located at the center of the core members 1a and 1b by a predetermined number of turns in opposite directions. And it manufactures by positioning the core member by which the AC line was wound, and couple | bonding with an adhesive agent.

  FIG. 4 is a circuit diagram showing an example of a noise filter including an inductance element according to the present invention. In this example, noise countermeasures are taken in the AC power supply line. A correlation capacitor 11 is connected between a pair of AC lines 10a and 10b connected to a commercial power source. The correlation capacitor 11 removes normal mode noise. The inductance element 12 according to the present invention is connected to the other ends of the AC lines 10a and 10b. A series circuit of correlation capacitors 13 and 14 is connected to the other end side of the inductance element 12, and a connection point of the correlation capacitors 13 and 14 is connected to a reference potential. Common mode noise is mainly removed by the inductance element 12 and the correlation capacitors 13 and 14. The correlation capacitors 13 and 14 serve to bypass noise to GND. A second inductance element 15 is connected after the series circuit of two correlation capacitors. The second inductance element 15 is a normal mode choke coil, and removes normal mode noise together with the correlation capacitor 11.

  Next, the noise attenuation effect of the inductance element according to the present invention will be described. The noise level was measured by connecting the inductance element according to the present invention and the conventional choke coil to the AC power line. FIG. 4 is a graph showing the measurement result of the noise level, where the horizontal axis indicates the frequency and the vertical axis indicates the noise level (dB). 4A shows the noise level when the inductance element shown in FIG. 1 is connected to the power supply line as a clamp core, and FIG. 4B shows a conventional common mode in which a coil is wound around the ring core around the power supply line. Indicates the noise level when a choke coil is connected. A 200 V, 50 Hz AC power source was used as the power source. 4 (A) and 4 (B) are compared, a remarkable difference is found in the low frequency band of 100 to 300 kHz. When the inductance element according to the present invention is used, the conventional choke coil is used. The noise level is more strongly suppressed than that, for example, about 8 dB in the vicinity of 150 KHz. As is clear from the experimental results, it was confirmed that the inductance element according to the present invention exhibits a noise attenuation effect superior to that of the conventional choke coil. The experimental result shown in FIG. 4 is an example, and it has been confirmed by experiments that a noise attenuation effect can be exhibited in a band from a low frequency band to 1 MHz when an experiment is applied to other products.

Example 2 is shown in FIG. Example 2 is an inductor element provided with the structure mounted in a board | substrate.
3A is a cross-sectional view taken along a plane including the axis of the core core, as in FIG. 1A, and FIG. 3B has two pieces as in FIG. 1B. It is a perspective view which shows and separates the core member and the bobbin. The inductance element of this embodiment is mounted on a unit and used for an input filter (choke coil). The bobbin 7 is integrated with the terminal 9 and the leg 8 to form a mounting tool 20. The bobbin 7 surrounds the core core 2 and is made of an insulating material. The legs 8 are made of the same material as the bobbin. On the other hand, the mounting tool 20 includes a plurality of terminals 9. The terminals 9 are fixed to the legs 8 located at both ends of the bobbin 7, and have a suitable structure for mounting on a substrate (not shown). Any known technique can be used for fixing the terminal 9 to the leg 8.
In the second embodiment, as shown in FIG. 2, the pair of AC wires 5a and 6a (FIGS. 1 and 2) are wound around the bobbin 7 in opposite directions. That is, the bobbin 7 covers the core core 2 without being wound directly around the core core 2. The noise attenuation effect when mounted is the same as that of the first embodiment.

It is a figure which shows an example of the inductance element by Example 1 of this invention. It is a figure which shows the winding direction of the alternating current line by Example 1 of this invention. It is a figure which shows an example of the inductance element by Example 2 by this invention. It is a circuit diagram which shows an example of the noise filter by this invention. It is a graph which shows the measurement result of a noise level.

DESCRIPTION OF SYMBOLS 1 Core main body 1a, 1b Core member 2 Core core 3 Shield core 4a, 4b Opening part 5a, 5b AC line 6a, 6b Winding 7 Bobbin 8 Leg 9 Terminal 10a, 10b AC line 11 Correlation capacitor 12 Inductance element 13, 14 Correlation Capacitor 15 Inductance element 20 Mounting tool

Claims (8)

An inductance element used for a noise filter connected between a commercial power supply and a load device,
First and second AC lines having one end connected to a commercial power source and the other end connected to the load device side;
A core body made of a magnetic material and including a core core around which the AC line is wound and a spherical shell-shaped shield core that surrounds the core core,
The inductance element, wherein the first and second AC lines are wound in opposite directions around the core core of the core body. 2. The inductance element according to claim 1, wherein the first and second AC lines are wound in opposite directions around the core core to form first and second windings. The inductance element, wherein the second winding is magnetically shielded by the shield core. 3. The inductance element according to claim 1, wherein the core body includes two core members that are divided into two along a plane orthogonal to the axis of the core core. . 4. The inductance element according to claim 3, wherein at least one of the core members is formed with a flange parallel to a surface orthogonal to the axis of the core core so as to be mountable on a substrate. An inductance element characterized by that. 2. The inductance element according to claim 1, wherein the AC line is wound directly around a core core, and the inductance element has an external structure disposed outside the load device. . 2. The inductance element according to claim 1, wherein the AC line is directly wound around a bobbin surrounding a core core, and the bobbin includes a terminal and a plurality of legs, and is configured to be mountable on a substrate. Inductance element. A noise filter connected between a commercial power source and a load device and including an inductance element and a capacitive element, wherein the inductance element is
First and second AC lines having one end connected to a commercial power source and the other end connected to the load device side;
A core body made of a magnetic material and including a core core around which the AC line is wound and a spherical shell-shaped shield core that surrounds the core core,
The first and second AC wires are wound around the core core of the core body in opposite directions to form first and second windings, and these first and second windings Is noise shielded by the shield core. A clamp core that is connected to an AC power line and attenuates noise,
First and second AC lines having one end connected to a commercial power source and the other end connected to the load device side;
A core body made of a magnetic material and including a core core around which the AC line is wound and a spherical shell-shaped shield core that surrounds the core core,
The first and second AC wires are wound around the core core of the core body in opposite directions to form first and second windings, and these first and second windings Is clamped magnetically by the shield core.

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