WO2021205565A1

WO2021205565A1 - Dual mode choke coil

Info

Publication number: WO2021205565A1
Application number: PCT/JP2020/015816
Authority: WO
Inventors: 白木　康博
Original assignee: 三菱電機株式会社
Priority date: 2020-04-08
Filing date: 2020-04-08
Publication date: 2021-10-14

Abstract

A dual mode choke coil (1) comprises: a first magnetic core (10); a second magnetic core (20); a magnetic cylindrical body (40); a first coil (30); and a second coil (35). A first winding direction of the first coil (30) is opposite to a second winding direction of the second coil (35). A first magnetic resistance of a first center magnetic path against an alternating-current magnetic flux formed by a normal mode noise current is less than a second magnetic resistance of a second center magnetic path against the alternating current magnetic flux. A third magnetic resistance of the first center magnetic path against a direct-current magnetic flux formed by a direct current flowing through the first coil (30) and the second coil (35) is greater than a fourth magnetic resistance of a second center magnetic path against the direct current magnetic flux.

Description

Dual mode choke coil

This disclosure relates to a dual mode choke coil.

Japanese Unexamined Patent Publication No. 2007-235580 (Patent Document 1) discloses a dual-mode choke coil. The dual mode choke coil includes a first magnetic core, a second magnetic core, a first coil, and a second coil. A gap is provided between the first magnetic core and the second magnetic core.

The dual mode choke coil is arranged in the electric circuit connecting the power supply and the inverter connected to the load, for example. Electromagnetic interference (EMI) noise is generated by the high-speed switching operation of the inverter. This EMI noise mainly includes normal mode noise and common mode noise. The normal mode noise propagates as a normal mode noise current between the positive side electric wire and the negative side electric wire extending between the power supply and the inverter. Therefore, the normal mode noise current propagates in the positive and negative electric wires extending between the power supply and the inverter in opposite directions. The common mode noise propagates as a common mode noise current between the positive wire and the ground and between the negative wire and the ground. Therefore, the common mode noise current propagates in the same direction between the positive side electric wire and the negative side electric wire extending between the power supply and the inverter.

The first AC magnetic flux formed by the normal mode noise current passes through the first magnetic core and the second magnetic core. The second AC magnetic flux formed by the common mode noise current passes through the first magnetic core and the second magnetic core. The first magnetic core and the second magnetic core have a high inductance with respect to the first AC magnetic flux and the second AC magnetic flux, so that the first magnetic core and the second magnetic core have the first AC magnetic flux. It has a high impedance with respect to the second AC magnetic flux. The dual mode choke coil attenuates and eliminates the normal mode noise current and the common mode noise current. It functions as a noise filter for normal mode noise current and common mode noise current.

Japanese Unexamined Patent Publication No. 2007-235580

When the dual mode choke coil is connected to a DC power supply, a direct current flows from the DC power supply to the dual mode choke coil. The direct current magnetic flux formed by this direct current passes through the first magnetic core and the second magnetic core. The direct current propagates between the positive and negative wires extending between the power supply and the inverter, similar to the normal mode noise current. Therefore, the magnetic path of the DC magnetic flux in the dual mode choke coil is the same as the magnetic path of the first AC magnetic flux in the dual mode choke coil. The DC magnetic flux causes magnetic saturation of the first magnetic core and the second magnetic core with respect to the smaller first AC magnetic flux. The inductance of the dual-mode choke coil with respect to the normal-mode noise current decreases, and the impedance of the dual-mode choke coil with respect to the normal-mode noise current also decreases. The ability of the dual mode choke coil to remove normal mode noise current is reduced.

In order to prevent a decrease in the normal mode noise current removal ability of the dual mode choke coil, the length of the gap between the first magnetic core and the second magnetic core is increased to increase the length of the gap between the first magnetic core and the second magnetic core. It is necessary to prevent magnetic saturation of the. However, if the length of the gap between the first magnetic core and the second magnetic core is increased, the inductance of the dual mode choke coil with respect to the normal mode noise current decreases, and the dual mode choke coil with respect to the normal mode noise current decreases. Impedance also drops. The ability of the dual mode choke coil to remove normal mode noise current is reduced.

The present disclosure has been made in view of the above problems, and an object thereof is to suppress a decrease in the ability of a dual mode choke coil to remove a normal mode noise current.

The dual mode choke coil of the present disclosure can remove the normal mode noise current and the common mode noise current. The dual mode choke coil includes a first magnetic core, a second magnetic core, a magnetic cylinder, a first coil, and a second coil. The first magnetic core includes a first yoke, a first side magnetic leg, a second side magnetic leg, and a first central magnetic leg. The first side magnetic leg, the second side magnetic leg, and the first central magnetic leg extend from the first yoke. The first central magnetic leg is arranged between the first side magnetic leg and the second side magnetic leg. The second magnetic core includes a second yoke, a third side magnetic leg, a fourth side magnetic leg, and a second central magnetic leg. The third side magnetic leg, the fourth side magnetic leg, and the second central magnetic leg extend from the second yoke. The second central magnetic leg is arranged between the third side magnetic leg and the fourth side magnetic leg. The first side magnetic leg and the third side magnetic leg are in contact with each other. The second side magnetic leg and the fourth side magnetic leg are in contact with each other. The first central magnetic leg and the second central magnetic leg are separated from each other with a first gap.

The first central magnetic leg and the second central magnetic leg are inserted into the magnetic cylinder and separated from the magnetic cylinder. The magnetic cylinder is separated from the first yoke with a second gap. The magnetic cylinder is separated from the second yoke with a third gap. The first coil is wound around a first side magnetic leg and a third side magnetic leg. The second coil is wound around a second side magnetic leg and a fourth side magnetic leg. The first winding direction of the first coil is opposite to the second winding direction of the second coil. The first reluctance of the first central magnetic path with respect to the AC magnetic flux is smaller than the second magnetic resistance of the second central magnetic path with respect to the AC magnetic flux. The AC magnetic flux is formed by the normal mode noise current flowing through the first coil and the second coil. The third reluctance of the first central magnetic path with respect to the DC magnetic flux is larger than the fourth magnetic resistance of the second central magnetic path with respect to the DC magnetic flux. The direct current magnetic flux is formed by the direct current flowing through the first coil and the second coil. The first central magnetic path is a magnetic path formed by the first central magnetic leg, the first gap, and the second central magnetic leg. The second central magnetic path is a magnetic path formed by the second gap, the magnetic cylinder, and the third gap.

In the dual mode choke coil of the present disclosure, the magnetic path of the AC magnetic flux formed by the normal mode noise current can be made different from the magnetic path of the DC magnetic flux formed by the DC current. The first magnetic core and the second with respect to the AC magnetic flux formed by the normal mode noise current without increasing the first gap length of the first gap between the first central magnetic leg and the second central magnetic leg. Magnetic saturation of the magnetic core is less likely to occur. Further, since the length of the first gap of the first gap between the first central magnetic leg and the second central magnetic leg is not increased, the decrease in the inductance and impedance of the dual mode choke coil with respect to the normal mode noise current can be suppressed. In this way, it is possible to suppress a decrease in the noise removing ability of the dual mode choke coil with respect to the normal mode noise current.

It is a circuit diagram of the power conversion apparatus of Embodiment 1. It is the schematic of the dual mode choke coil of Embodiment 1. FIG. FIG. 5 is a schematic cross-sectional view taken along the cross-sectional line III-III shown in FIG. 2 of the dual-mode choke coil of the first embodiment. FIG. 5 is a schematic cross-sectional view taken along the cross-sectional line IV-IV shown in FIG. 2 of the dual-mode choke coil of the first embodiment. FIG. 5 is a schematic cross-sectional view taken along the cross-sectional line VV shown in FIG. 2 of the dual-mode choke coil of the first embodiment. It is a figure which shows the graph which shows the frequency characteristic of the specific magnetic permeability of a 1st magnetic core, the frequency characteristic of the specific magnetic permeability of a 2nd magnetic core, and the frequency characteristic of the specific magnetic permeability of a magnetic cylinder. It is the schematic which shows the magnetic path of the 1st AC magnetic flux formed by the normal mode noise current in the dual mode choke coil of Embodiment 1. FIG. It is the schematic which shows the magnetic path of the direct current magnetic flux formed by the direct current in the dual mode choke coil of Embodiment 1. FIG. It is the schematic which shows the magnetic path of the 2nd AC magnetic flux formed by the common mode noise current in the dual mode choke coil of Embodiment 1. FIG. It is the schematic of the dual mode choke coil of Embodiment 2. FIG. 5 is a schematic cross-sectional view taken along the cross-sectional line XI-XI shown in FIG. 10 of the dual-mode choke coil of the second embodiment. FIG. 5 is a schematic cross-sectional view taken along the cross-sectional line XII-XII shown in FIG. 10 of the dual-mode choke coil of the second embodiment. FIG. 5 is a schematic cross-sectional view taken along the cross-sectional line XIII-XIII shown in FIG. 10 of the dual-mode choke coil of the second embodiment.

Hereinafter, embodiments of the present disclosure will be described. The same reference number is assigned to the same configuration, and the description is not repeated.

Embodiment 1.
The power conversion device 2 of the first embodiment will be described with reference to FIG. The power conversion device 2 is connected to the DC power supply 3 and the load 9. In a modified example of the present embodiment, the DC power supply 3 may include an AC power supply (not shown) and a rectifier (not shown) that converts an AC voltage from the AC power supply into a tidal current voltage. The load 9 is, for example, a motor.

The power conversion device 2 includes a positive electric wire 4a, a negative electric wire 4b, a capacitor 5, a dual mode choke coil 1, a capacitor 6a, a capacitor 6b, and an inverter 8.

The positive side electric wire 4a is connected to the positive electrode of the DC power supply 3. The positive side electric wire 4a extends from the DC power supply 3 to the inverter 8. The negative side electric wire 4b is connected to the negative electrode of the DC power supply 3. The negative wire 4b extends from the DC power supply 3 to the inverter 8.

The capacitor 5 is connected to the positive side electric wire 4a and the negative side electric wire 4b. The capacitor 5 is arranged on the input side (DC power supply 3 side) of the dual mode choke coil 1. The dual mode choke coil 1 is connected to the positive side electric wire 4a and the negative side electric wire 4b.

The inverter 8 is connected to the positive side electric wire 4a and the negative side electric wire 4b. The inverter 8 is arranged on the output side (load 9 side) of the dual mode choke coil 1. A load 9 is connected to the output side of the inverter 8. The inverter 8 includes a plurality of switching elements (not shown) such as a metal oxide semiconductor field effect transistor (MOSFET) or an insulated gate bipolar transistor (IGBT). The inverter 8 converts the DC voltage input to the inverter 8 into an AC voltage, and outputs the AC voltage to the load 9.

The capacitor 6a is connected to the portion of the positive electric wire 4a extending between the dual mode choke coil 1 and the inverter 8 and the ground 7. The capacitor 6b is connected to a portion of the negative electric wire 4b extending between the dual mode choke coil 1 and the inverter 8 and the ground 7.

Electromagnetic interference (EMI) noise is generated by the high-speed switching operation of the inverter 8. This EMI noise mainly includes normal mode noise and common mode noise. The normal mode noise propagates as a normal mode noise current between the positive side electric wire 4a and the negative side electric wire 4b extending between the DC power supply 3 and the inverter 8. The common mode noise propagates as a common mode noise current between the positive side electric wire 4a and the ground and between the negative side electric wire 4b and the ground. The normal mode noise current and the common mode noise current are alternating currents because they are generated due to the high-speed switching operation of the inverter 8. The dual mode choke coil 1 can attenuate the normal mode noise current and the common mode noise current to remove the normal mode noise current and the common mode noise current.

The dual mode choke coil 1 of the first embodiment will be described with reference to FIGS. 2 to 6. The dual mode choke coil 1 includes a first magnetic core 10, a second magnetic core 20, a first coil 30, a second coil 35, and a magnetic cylinder 40.

The first magnetic core 10 includes a first yoke 11, a first side magnetic leg 13, a second side magnetic leg 14, and a first central magnetic leg 12. The longitudinal direction of the first yoke 11 is the x direction. The first side magnetic leg 13, the second side magnetic leg 14, and the first central magnetic leg 12 extend from the first yoke 11. The first central magnetic leg 12 is arranged between the first side magnetic leg 13 and the second side magnetic leg 14. The longitudinal direction of the first side magnetic leg 13 is, for example, the y direction perpendicular to the longitudinal direction (x direction) of the first yoke 11. The longitudinal direction (y direction) of the second side magnetic leg 14 is, for example, the y direction perpendicular to the longitudinal direction (x direction) of the first yoke 11. The longitudinal direction of the first central magnetic leg 12 is, for example, the y direction perpendicular to the longitudinal direction (x direction) of the first yoke 11. The first magnetic core 10 is an E-type core.

As shown in FIGS. 3 and 4, the first central magnetic leg 12 has a length L ₁₂ , a width a _1, and a height b ₁ . The length L ₁₂ of the first central magnetic leg 12 is the length of the first central magnetic leg 12 in the longitudinal direction (y direction) of the first central magnetic leg 12. The width a ₁ of the first central magnetic leg 12 is perpendicular to the longitudinal direction (y direction) of the first central magnetic leg 12 and is along the longitudinal direction (x direction) of the first yoke 11. It is the length of the first central magnetic leg 12 in the width direction (x direction). The height b ₁ of the first central magnetic leg 12 is the first central magnetic leg 12 perpendicular to the longitudinal direction (y direction) of the first central magnetic leg 12 and the width direction (x direction) of the first central magnetic leg 12. It is the length of the first central magnetic leg 12 in the height direction (z direction) of.

Sectional area S ₁₂ of the first central magnetic leg 12 is given by the product of width a ₁ and a height b _1. The cross-sectional area S ₁₂ of the first central magnetic leg 12 is the area of the first central magnetic leg 12 in the cross section perpendicular to the longitudinal direction (y direction) of the first central magnetic leg 12. The width a ₁ of the first central magnetic leg 12 _{may be equal to the height b 1} of the first central magnetic leg 12, and the cross section of the first central magnetic leg 12 may have a square shape. The width a ₁ of the first central magnetic leg 12 _{may be different from the height b 1} of the first central magnetic leg 12, and the cross section of the first central magnetic leg 12 may have a rectangular shape.

The first side magnetic leg 13 includes an end face 13a distal to the first yoke 11. The second side magnetic leg 14 includes an end face 14a distal to the first yoke 11. The first central magnetic leg 12 includes an end face 12a distal to the first yoke 11.

The second magnetic core 20 includes a second yoke 21, a third side magnetic leg 23, a fourth side magnetic leg 24, and a second central magnetic leg 22. The longitudinal direction of the second yoke 21 is the x direction. The third side magnetic leg 23, the fourth side magnetic leg 24, and the second central magnetic leg 22 extend from the second yoke 21. The second central magnetic leg 22 is arranged between the third side magnetic leg 23 and the fourth side magnetic leg 24. The longitudinal direction of the third side magnetic leg 23 is, for example, the y direction perpendicular to the longitudinal direction (x direction) of the second yoke 21. The longitudinal direction (y direction) of the fourth side magnetic leg 24 is, for example, the y direction perpendicular to the longitudinal direction (x direction) of the second yoke 21. The longitudinal direction of the second central magnetic leg 22 is, for example, the y direction perpendicular to the longitudinal direction (x direction) of the second yoke 21. The second magnetic core 20 is an E-type core.

As shown in FIGS. 3 and 5, the second central magnetic leg 22 has a length L ₂₂ and a width a ₂ and a height b ₂ . The length L ₂₂ of the second central magnetic leg 22 is the length of the second central magnetic leg 22 in the longitudinal direction (y direction) of the second central magnetic leg 22. The width a ₂ of the second central magnetic leg 22 is perpendicular to the longitudinal direction (y direction) of the second central magnetic leg 22 and is along the longitudinal direction (x direction) of the second yoke 21. It is the length of the second central magnetic leg 22 in the width direction (x direction). The height b ₂ of the second central magnetic leg 22 is the second central magnetic leg 22 perpendicular to the longitudinal direction (y direction) of the second central magnetic leg 22 and the width direction (x direction) of the second central magnetic leg 22. Is the length of the second central magnetic leg 22 in the height direction (z direction) of.

Sectional area S ₂₂ of the second central magnetic leg 22 is given by the product of width a ₂ and height b _2. The cross-sectional area S ₂₂ of the second central magnetic leg 22 is the area of the second central magnetic leg 22 in the cross section perpendicular to the longitudinal direction (y direction) of the second central magnetic leg 22. The width a ₂ of the second central magnetic leg 22 _{may be equal to the height b 2} of the second central magnetic leg 22, and the cross section of the second central magnetic leg 22 may have a square shape. The width a ₂ of the second central magnetic leg 22 _{may be different from the height b 2} of the second central magnetic leg 22, and the cross section of the second central magnetic leg 22 may have a rectangular shape. Width a ₂ of the second central magnetic leg 22 is equal to the width a ₁ of the first central magnetic leg 12, and the height b ₂ of the second center leg 22 to the height b ₁ of the first central magnetic leg 12 May be equal. Sectional area S ₂₂ of the second central magnetic leg 22 may be equal to the cross-sectional area S ₁₂ of the first central magnetic leg 12.

The third side magnetic leg 23 includes an end face 23a distal to the second yoke 21. The fourth side magnetic leg 24 includes an end face 24a distal to the second yoke 21. The second central magnetic leg 22 includes an end face 22a distal to the second yoke 21.

The first side magnetic leg 13 and the third side magnetic leg 23 are in contact with each other. Specifically, the end surface 13a of the first side magnetic leg 13 is in surface contact with the end surface 23a of the third side magnetic leg 23. The second side magnetic leg 14 and the fourth side magnetic leg 24 are in contact with each other. Specifically, the end surface 14a of the second side magnetic leg 14 is in surface contact with the end surface 24a of the fourth side magnetic leg 24. The first central magnetic leg 12 and the second central magnetic leg 22 are separated from each other with a first gap 17. Specifically, the end surface 12a of the first central magnetic leg 12 and the end surface 22a of the second central magnetic leg 22 are separated from each other with a first gap 17. The first gap length G ₁ of the first gap 17 includes the first central magnetic leg 12 (end face 12a) and the second central magnetic leg 22 (end face 22a) in the longitudinal direction (y direction) of the first central magnetic leg 12. Is the length between.

The first magnetic core 10 and the second magnetic core 20 are made of a soft magnetic material. The first magnetic core 10 and the second magnetic core 20 are, for example, a ferrite core, an amorphous core, or an iron dust core. The ferrite core is, for example, a manganese-zinc (Mn—Zn) -based ferrite core or a nickel-zinc (Ni—Zn) -based ferrite core. The amorphous core is formed of, for example, an iron-based amorphous alloy. The iron dust core is a magnetic core formed by pressure molding iron powder. The iron dust core is made of, for example, any material selected from the group consisting of pure iron, Fe—Si alloys, Fe—Si—Al alloys, Ni—Fe alloys or Ni—Fe—Mo alloys.

The first coil 30 is a conducting wire made of a metal material such as copper, for example. The first coil 30 is wound around the first side magnetic leg 13 and the third side magnetic leg 23. The first coil 30 is a part of the positive electric wire 4a. A terminal 31 is provided at the end of the first coil 30 proximal to the DC power supply 3. A terminal 32 is provided at the end of the first coil 30 proximal to the inverter 8.

The second coil 35 is a conducting wire made of a metal material such as copper, for example. The second coil 35 is wound around the second side magnetic leg 14 and the fourth side magnetic leg 24. The second coil 35 is a part of the negative side electric wire 4b. A terminal 36 is provided at the end of the second coil 35 proximal to the DC power supply 3. A terminal 37 is provided at the end of the second coil 35 proximal to the inverter 8. The first winding direction of the first coil 30 is opposite to the second winding direction of the second coil 35.

The longitudinal direction of the magnetic cylinder 40 is the longitudinal direction (y direction) of the first central magnetic leg 12 and the longitudinal direction (y direction) of the second central magnetic leg 22. As shown in FIG. 3, the magnetic cylinder 40 has a length L ₄₀ . The length L ₄₀ of the magnetic cylinder 40 is the length of the magnetic cylinder 40 in the longitudinal direction (y direction) of the magnetic cylinder 40. The magnetic cylinder 40 includes an end face 41 facing the first yoke 11 and an end face 42 facing the second yoke 21.

The magnetic cylinder 40 is separated from the first yoke 11 with a second gap 43. _{The second gap length G 2} of the second gap 43 is the length between the first yoke 11 and the magnetic cylinder 40 (end surface 41) in the longitudinal direction (y direction) of the magnetic cylinder 40. The magnetic cylinder 40 is separated from the second yoke 21 with a third gap 44. _{The third gap length G 3} of the third gap 44 is the length between the second yoke 21 and the magnetic cylinder 40 (end surface 42) in the longitudinal direction (y direction) of the magnetic cylinder 40. _{The first gap length G 1} of the first gap 17 between the first central magnetic leg 12 and the second central magnetic leg 22 is the second gap length G _{2 of} the second gap 43 and the third gap of the third gap 44. it may be greater than the sum of the length G _3.

The first central magnetic leg 12 and the second central magnetic leg 22 are inserted into the magnetic cylinder 40. The end surface 12a of the first central magnetic leg 12, the end surface 22a of the second central magnetic leg 22, and the first gap 17 between the first central magnetic leg 12 and the second central magnetic leg 22 are magnetic cylinders 40. It is in the cavity of the magnetic cylinder 40 defined by the inner surface 40b of the.

The magnetic cylinder 40 is separated from the first central magnetic leg 12 and the second central magnetic leg 22. Specifically, the inner surface 40b of the magnetic cylinder 40 is separated from the first central magnetic leg 12 and the second central magnetic leg 22. _{The gap length g 11} (see FIG. 4) between the first central magnetic leg 12 and the inner surface 40b of the magnetic cylinder 40 in the width direction (x direction) of the first central magnetic leg 12 is the first central magnetic leg. _{It may be equal to the gap length g 12} (see FIG. 4) between the first central magnetic leg 12 and the inner surface 40b of the magnetic cylinder 40 in the height direction (z direction) of 12. _{The gap length g 21} (see FIG. 5) between the second central magnetic leg 22 and the inner surface 40b of the magnetic cylinder 40 in the width direction (x direction) of the second central magnetic leg 22 is the second central magnetic leg 22. _{It may be equal to the gap length g 22} (see FIG. 5) between the second central magnetic leg 22 and the inner surface 40b of the magnetic cylinder 40 in the height direction (z direction) of 22.

_{The gap length g 11} (see FIG. 4) between the first central magnetic leg 12 and the inner surface 40b of the magnetic cylinder 40 in the width direction (x direction) of the first central magnetic leg 12 is the second central magnetic leg. _{It may be equal to the gap length g 21} (see FIG. 5) between the second central magnetic leg 22 and the inner surface 40b of the magnetic cylinder 40 in the width direction (x direction) of 22. _{The gap length g 12} (see FIG. 4) between the first central magnetic leg 12 and the inner surface 40b of the magnetic cylinder 40 in the height direction (z direction) of the first central magnetic leg 12 is the second central magnetic leg. _{It may be equal to the gap length g 22} (see FIG. 5) between the second central magnetic leg 22 and the inner surface 40b of the magnetic cylinder 40 in the height direction (z direction) of the leg 22.

As shown in FIGS. 4 and 5, the outer surface 40a of the magnetic cylinder 40 has a width p ₁ and a height p ₂ . _{The width p 1} of the outer surface 40a of the magnetic cylinder 40 is perpendicular to the longitudinal direction (y direction) of the magnetic cylinder 40 and is the width direction of the magnetic cylinder 40 along the longitudinal direction (x direction) of the first yoke 11. It is the length of the outer surface 40a of the magnetic cylinder 40 in the (x direction). _{The height p 2} of the outer surface 40a of the magnetic cylinder 40 is the height direction of the magnetic cylinder 40 perpendicular to the longitudinal direction (y direction) of the magnetic cylinder 40 and the width direction (x direction) of the magnetic cylinder 40. (Z direction) is the length of the outer surface 40a of the magnetic cylinder 40. The width p ₁ of the outer surface 40a of _{the magnetic cylinder 40 may be equal to the height p 2} of the outer surface 40a of the magnetic cylinder 40, or different from _{the height p 2 of the outer surface 40a of the magnetic cylinder 40.} May be good.

As shown in FIGS. 4 and 5, the inner surface 40b of the magnetic cylinder 40 has a width q ₁ and a height q ₂ . _{The width q 1} of the inner surface 40b of the magnetic cylinder 40 is perpendicular to the longitudinal direction (y direction) of the magnetic cylinder 40 and is the width direction of the magnetic cylinder 40 along the longitudinal direction (x direction) of the first yoke 11. It is the length of the inner surface 40b of the magnetic cylinder 40 in the (x direction). _{The height q 2} of the inner surface 40b of the magnetic cylinder 40 is the height direction of the magnetic cylinder 40 perpendicular to the longitudinal direction (y direction) of the magnetic cylinder 40 and the width direction (x direction) of the magnetic cylinder 40. (Z direction) is the length of the inner surface 40b of the magnetic cylinder 40. _{The width q 1} of the inner surface 40b of the magnetic cylinder 40 may be equal to _{the height q 2} of the inner surface 40b of the magnetic cylinder 40. The width q ₁ of the inner surface 40b of _{the magnetic cylinder 40 may be equal to the height q 2} of the inner surface 40b of the magnetic cylinder 40, or different from _{the height q 2 of the inner surface 40b of the magnetic cylinder 40.} May be good.

The cross-sectional area S ₄₀ of the magnetic cylinder 40 is given by the equation (1). The cross-sectional area S ₄₀ of the magnetic cylinder 40 is the area of the magnetic cylinder 40 in a cross section perpendicular to the longitudinal direction (y direction) of the magnetic cylinder 40.

S ₄₀ = p ₁ · p ₂ −q ₁ · q ₂ (1)
The magnetic cylinder 40 is made of a material different from that of the first magnetic core 10 and the second magnetic core 20. The saturation magnetic flux density of the magnetic cylinder 40 is larger than the saturation magnetic flux density of the first magnetic core 10 and larger than the saturation magnetic flux density of the second magnetic core 20. The saturation magnetic flux density of the magnetic cylinder 40 is, for example, 1.5 tesla or more. The magnetic cylinder 40 is made of, for example, a rolled steel material for general structure (SS material), a silicon steel plate, or a permalloy.

_{The frequency characteristic μ r40} (ω) of the specific magnetic permeability of the magnetic cylinder 40 is different from the frequency characteristic of the specific magnetic permeability of the first central magnetic leg 12 of the first magnetic core 10. In the present embodiment, the first yoke 11, the first central magnetic leg 12, the first side magnetic leg 13 and the second side magnetic leg 14 are formed of a single magnetic material, and the first magnetic core 10 is the first. 1 The frequency characteristic of the relative permeability of the central magnetic leg 12 _{is equal to the frequency characteristic μ r10} (ω) of the relative permeability of the first magnetic core 10. As shown in FIG. 6, the frequency characteristic μ _r40 (ω) of the specific magnetic permeability of the magnetic cylinder 40 is different from _{the frequency characteristic μ r10} (ω) of the specific magnetic permeability of the first magnetic core 10.

_{The frequency characteristic μ r40} (ω) of the specific magnetic permeability of the magnetic cylinder 40 is different from the frequency characteristic of the specific magnetic permeability of the second central magnetic leg 22 of the second magnetic core 20. In the present embodiment, the second yoke 21, the second central magnetic leg 22, the third side magnetic leg 23, and the fourth side magnetic leg 24 are formed of a single magnetic material, and the second magnetic core 20 is the second. 2. The frequency characteristic of the relative permeability of the central magnetic leg 22 _{is equal to the frequency characteristic μ r10} (ω) of the relative permeability of the second magnetic core 20. As shown in FIG. 6, the frequency characteristic μ _r40 _{(ω) of the specific magnetic permeability of the magnetic cylinder 40 is different from the frequency characteristic μ r20} (ω) of the specific magnetic permeability of the second magnetic core 20.

_{Specifically, the relative magnetic permeability μ r10} (ω = ω _n ) of the first central magnetic leg 12 with _{respect to the first AC magnetic field is the relative magnetic permeability μ r40} (ω = ω _n ) of the magnetic cylinder 40 with respect to the first AC magnetic field. ) Greater. The relative magnetic permeability μ _r20 (ω = ω _n ) of the second central magnetic leg 22 with respect to the first AC magnetic field is larger than _{the relative magnetic permeability μ r40} (ω = ω _n ) of the magnetic cylinder 40 with respect to the first AC magnetic field. ω _n is the frequency of the first alternating magnetic field formed by the normal mode noise current. _{The frequency ω n} of the first AC magnetic field is equal to the frequency of the normal mode noise current.

_{Specifically, the relative permeability μ r10} (ω = ω _c ) of the first central magnetic leg 12 with _{respect to the second AC magnetic field is the relative permeability μ r40} (ω = ω _c ) of the magnetic cylinder 40 with respect to the second AC magnetic field. ) Greater. The relative magnetic permeability μ _r20 (ω = ω _c ) of the second central magnetic leg 22 with respect to the second AC magnetic field is larger than _{the relative magnetic permeability μ r40} (ω = ω _c ) of the magnetic cylinder 40 with respect to the second AC magnetic field. ω _c is the frequency of the second AC magnetic field formed by the common mode noise current. _{The frequency ω c} of the second AC magnetic field is equal to the frequency of the common mode noise current.

The normal mode noise current and the common mode noise current are generated due to the high-speed switching operation of the inverter 8 (see FIG. 1). Therefore, the frequency of the common mode noise current is substantially equal to the frequency of the normal mode noise current, and the frequency ω _c of the second AC magnetic field is substantially equal to _{the frequency ω n} of the first AC magnetic field. _{The frequency ω n} of the first AC magnetic field is, for example, 1 kHz or more. _{The frequency ω n} of the first AC magnetic field is, for example, 500 kHz or less. _{The frequency ω n} of the first AC magnetic field may be 150 kHz or less. _{The frequency ω c} of the second AC magnetic field is, for example, 1 kHz or more. _{The frequency ω c} of the second AC magnetic field is, for example, 500 kHz or less. _{The frequency ω c} of the second AC magnetic field may be 150 kHz or less.

_{The relative magnetic permeability μ r40} (ω = 0) of the magnetic cylinder 40 with respect to the DC magnetic field having a frequency of zero _{is larger than the relative magnetic permeability μ r10} (ω = 0) of the first central magnetic leg 12 with respect to the DC magnetic field, and The relative magnetic permeability of the second central magnetic _leg 22 with respect to the DC magnetic field is larger than μ r20 (ω = 0). The direct current is formed by a direct current flowing from the direct current power source 3 to the positive electric wire 4a including the first coil 30 and the negative electric wire 4b including the second coil 35.

The relative permeability μ _r10 (ω = ω _n ) is, for example, 100 or more. The relative magnetic permeability μ _r10 (ω = ω _n ) may be 500 or more, and may be 1000 or more. The relative permeability μ _r20 (ω = ω _n ) is, for example, 100 or more. The relative magnetic permeability μ _r20 (ω = ω _n ) may be 500 or more, and may be 1000 or more. The relative permeability μ _r40 (ω = ω _n ) is, for example, greater than 1 and less than or equal to 100. The relative magnetic permeability μ _r40 (ω = ω _n ) may be 50 or less, or 10 or less.

The relative permeability μ _r10 (ω = ω _c ) is, for example, 100 or more. The relative magnetic permeability μ _r10 (ω = ω _c ) may be 500 or more, and may be 1000 or more. The relative permeability μ _r20 (ω = ω _c ) is, for example, 100 or more. The relative magnetic permeability μ _r20 (ω = ω _c ) may be 500 or more, and may be 1000 or more. The relative permeability μ _r40 (ω = ω _c ) is, for example, greater than 1 and less than or equal to 100. The relative magnetic permeability μ _r40 (ω = ω _c ) may be 50 or less, or 10 or less.

The relative magnetic permeability μ _r40 (ω = 0) is, for example, 1000 or more. The relative magnetic permeability μ _r40 (ω = 0) may be, for example, 5000 or more, or 10000 or more. The relative magnetic permeability μ _r10 (ω = 0) is, for example, 100 or more. The relative magnetic permeability μ _r10 (ω = 0) may be 500 or more, or 1000 or more. The relative magnetic permeability μ _r20 (ω = 0) is, for example, 100 or more. The relative magnetic permeability μ _r20 (ω = 0) may be 500 or more, or 1000 or more.

For example, the relative magnetic permeability μ _r10 (ω = ω _n _{) is 10 times or more the specific} magnetic permeability μ r40 (ω = ω _n ), and is 10 times or more the specific magnetic permeability of the vacuum with respect to the first AC magnetic field. be. The relative magnetic permeability of the vacuum with respect to the first AC magnetic field is equal to 1. For example, the relative magnetic permeability μ _r10 (ω = ω _c _{) is 10 times or more the specific} magnetic permeability μ r40 (ω = ω _C ), and is 10 times or more the specific magnetic permeability of the vacuum with respect to the second AC magnetic field. be. The relative permeability of the vacuum with respect to the second AC magnetic field is equal to 1. For example, the relative magnetic permeability μ _r40 (ω = 0) is _{10 times or more the specific magnetic permeability μ r10} (ω = 0), and is 10 times or more the specific magnetic permeability μ _r20 (ω = 0). It is 100 times or more the relative magnetic permeability of vacuum with respect to a DC magnetic field. The relative magnetic permeability of a vacuum with respect to a DC magnetic field is equal to 1. For example, the relative magnetic permeability μ _r10 (ω = 0) is 10 times or more the relative magnetic permeability of a vacuum with respect to a DC magnetic field. The relative magnetic permeability μ _r20 (ω = 0) is 10 times or more the relative magnetic permeability of a vacuum with respect to a DC magnetic field.

The first reluctance R _mca (ω = ω _n ) of the first central magnetic path with respect to the first AC magnetic flux is smaller than _{the second reluctance R mcb} (ω = ω _{n) of the second central magnetic path with respect to the first AC magnetic flux.} .. The first AC magnetic flux is formed by the normal mode noise current. _{The frequency ω n} of the first AC magnetic flux is equal to the frequency of the normal mode noise current. The first central magnetic path is a magnetic path formed by the first central magnetic leg 12, the first gap 17, and the second central magnetic leg 22. The second central magnetic path is a magnetic path formed by the second gap 43, the magnetic cylinder 40, and the third gap 44.

The third reluctance R _mca (ω = 0) of the first central magnetic path with respect to the DC magnetic flux is _{larger than the fourth magnetic resistance R mcb} (ω = 0) of the second central magnetic path with respect to the DC magnetic flux. The direct current magnetic flux is formed by a direct current flowing through the positive electric wire 4a including the first coil 30 and the negative electric wire 4b including the second coil 35. The magnetic flux density of the DC magnetic flux in the magnetic cylinder 40 is smaller than the saturation magnetic flux density of the magnetic cylinder 40.

Specifically, the first reluctance R _mca (ω) of the first central magnetic path is given by the equation (2).
R _mca (ω) = R _m12 (ω) + R _m17 (ω) + R _m22 (ω) (2)
R _m12 (ω) represents the reluctance of the first central magnetic _{leg 12, R m17} (ω) represents the reluctance of the first gap 17, and R _m22 (ω) represents the reluctance of the second central magnetic leg 22. show. _{The width a 1} of the first central magnetic leg 12 is equal to the width a ₂ of the second central magnetic leg 22, the height _{b 1} of the first central magnetic leg 12 is equal _{to the height b 2 of the second central magnetic leg 22.} When the cross-sectional area S ₁₂ _{of the first central magnetic leg} 12 is equal to the cross-sectional area S ₂₂ of the second central magnetic leg 22, R m12 (ω) is given by Eq. (3), and R _m17 (ω) is given by Eq. (4). ), And R _m22 (ω) is given by equation (5). μ ₀ represents the magnetic permeability of vacuum. Since the first gap 17 is filled with air, μ _r17 (ω) is equal to 1.

R _m12 (ω) = L ₁₂ / (μ ₀・ μ _r10 (ω) ・ S ₁₂ ) = L ₁₂ / (μ ₀・ μ _r10 (ω) ・ a ₁・ b ₁ ) (3)
R _m17 (ω) = G ₁ / (μ ₀・ μ _r17 (ω) ・ S ₁₂ ) = G ₁ / (μ ₀・ μ _r17 (ω) ・ a ₁・ b ₁ ) (4)
R _m22 (ω) = L ₂₂ / (μ ₀・ μ _r20 (ω) ・ S ₂₂ ) = L ₂₂ / (μ ₀・ μ _r20 (ω) ・ a ₂・ b ₂ ) (5)
_{The second reluctance R mcb} (ω) of the second central magnetic path is given by Eq. (6).

R _mcb (ω) = R _m43 (ω) + R _m40 (ω) + R _m44 (ω) (6)
R _m43 (ω) represents the reluctance of the second gap 43, R _m40 (ω) represents the reluctance of the magnetic cylinder 40, and R _m44 (ω) represents the reluctance of the third gap 44. R _m43 (ω) is given by equation (7), R _m40 (ω) is given by equation (8), and R _m44 (ω) is given by equation (9). μ _r43 (ω) is equal to 1. μ _r44 (ω) is equal to 1.

R _m43 (ω) = G ₂ / (μ ₀・ μ _r43 (ω) ・ S ₄₀ ) = G ₂ / (μ ₀・ μ _r43 (ω) ・ (p ₁・ p _2- q ₁・ q ₂ )) (7)
R _m40 (ω) = L ₄₀ / (μ ₀・ μ _r40 (ω) ・ S ₄₀ ) = L ₄₀ / (μ ₀・ μ _r40 (ω) ・ (p ₁・ p _2- q ₁・ q ₂ )) (8)
R _m44 (ω) = G ₃ / (μ ₀・ μ _r44 (ω) ・ S ₄₀ ) = G ₃ / (μ ₀・ μ _r44 (ω) ・ (p ₁・ p _2- q ₁・ q ₂ )) (9)
As shown in FIG. 6, the equation (10) holds with respect to the magnitude relationship of the relative magnetic permeability of the substances constituting the first central magnetic path with respect to the first AC magnetic field formed by the normal mode noise current.

μ _r10 (ω = ω _n ) = μ _r20 (ω = ω _n ) ≫ _{μ r17} (ω = ω _n ) = 1 (10)
_{_{Therefore, R m12 (ω = ω n}} ) and R _m22 and (ω = ω _n) is very small relative to _{_{R m17 (ω = ω n)}} , R m12 (ω = ω n) and R _m22 ( ω = ω _n ) can be ignored for _{R m17} (ω = ω _n). In light of the equation _{(1), R mca (ω} = ω n) it is substantially can be regarded as equal to _{_{R m17 (ω = ω n)}} .

With reference to FIG. 6, the magnitude relationship of the relative magnetic permeability of the substances constituting the second central magnetic path with respect to the first AC magnetic field formed by the normal mode noise current is as follows. μ _r40 (ω = ω _n) has a value nearly equal to _{_{1 μ r43 (ω = ω n}} ) is equal to 1 mu _r44 and (ω = ω _n). For R _m43 (ω = ω _n ) and R _m44 (ω = ω _n ), R _m40 (ω = ω _n ) cannot be ignored. Therefore, R _mcb (ω = ω _n ) is given by Eq. (6).

When equation (11), in other words, equation (12) holds, the first reluctance R _mca (ω = ω _n ) of the first central magnetic path with respect to the first AC magnetic flux is set to the second central magnetic path with respect to the first AC magnetic flux. It can be made smaller than the second magnetic resistance R _mcb (ω = ω _n). Specifically, the first magnetic resistor R _mca the first central magnetic path for a first alternating magnetic flux (ω = ω _n) and the second magnetoresistance R _mcb of the second central magnetic path for the first alternating magnetic flux (omega = omega _Set _{G 1} , S ₁₂ , G ₂ , S ₄₀ , L ₄₀ , μ r40 (ω = ω _n ), G _3, etc. so that they are smaller than _n).

R _mca (ω = ω _n ) <R _mcb (ω = ω _n ) (11)
R _m17 (ω = ω _n ) <R _m43 (ω = ω _n ) + R _m40 (ω = ω _n ) + R _m44 (ω = ω _n ) (12)
As shown in FIG. 6, the equation (13) holds with respect to the magnitude relation of the relative magnetic permeability of the substances constituting the first central magnetic path with respect to the DC magnetic field having the frequency ω of zero.

μ _r10 (ω = 0) = μ _r20 (ω = 0) ≫ _{μ r17} (ω = 0) = 1 (13)
Therefore, R _m12 (ω = 0) and R _m22 and (omega = 0) becomes very small relative to _{R m17 (ω = 0),} R m12 (ω = 0) and R _m22 (ω = 0) _Can be ignored for R m17 (ω = 0). In light of the equation _{(1), R mca (ω} = 0) it is substantially can be regarded as equal to R _m17 (ω = 0).

With reference to FIG. 6, the equation (14) holds with respect to the magnitude relationship of the relative magnetic permeability of the substances constituting the second central magnetic path with respect to the DC magnetic field.

_{μ r40 (ω = 0) »μ} r43 (ω = 0) = μ r44 (ω = 0) = 1 (14)
Therefore, R _m40 (ω = 0) is _{much smaller than R m43} (ω = 0) and R _m44 (ω = 0), and R _m40 (ω = 0) is R _m43 (ω = 0) and R. _{It can be ignored for m44} (ω = 0). R _mcb (ω = 0) is given by Eq. (15).

R _mcb (ω = 0) = R _m43 (ω = 0) + R _m44 (ω = 0) (15)
When equation (16), in other words, equation (17) holds, the third magnetic resistance R _mca (ω = 0) of the first central magnetic path with respect to the DC magnetic flux and the fourth magnetic resistance of the second central magnetic path with respect to the DC magnetic flux. It can be larger than R _mcb (ω = 0). Specifically, the third magnetic resistance R _mca (ω = 0) of the first central magnetic path with respect to the DC magnetic flux _{is larger than the fourth magnetic resistance R mcb} (ω = 0) of the second central magnetic path with respect to the DC magnetic flux. Set to G ₁ , S ₁₂ , G ₂ , S _40, G ₃ , and so on.

R _mca (ω = 0)> R _mcb (ω = 0) (16)
R _m17 (ω = 0)> R _m43 (ω = 0) + R _m44 (ω = 0) (17)
The operation of the dual mode choke coil 1 of the present embodiment will be described with reference to FIGS. 7 to 9.

Normal mode noise current I _n propagates between the positive side wire 4a and the negative wire 4b extending between the DC power source 3 and the inverter 8. The first winding direction of the first coil 30 is opposite to the second winding direction of the second coil 35. Therefore, the normal mode noise current I _n from the inverter 8 (see FIG. 1) flows in opposite directions and a negative wire 4b which includes a positive-side wire 4a and the second coil 35 including the first coil 30. _{The DC current I dc} from the DC power supply 3 (see FIG. 1) also flows in opposite directions to the positive side electric wire 4a including the first coil 30 and the negative side electric wire 4b including the second coil 35. A first alternating

magnetic flux

50, 51 formed by the normal mode noise current I _n, the DC

magnetic flux

53 and 54 are formed by a DC current I _dc is the first center leg 12 and the first gap 17 and the second central It passes through a first central magnetic path formed by the magnetic legs 22 or a second central magnetic path formed by a second gap 43, a magnetic cylinder 40, and a third gap 44.

Normal mode noise current first magnetoresistance R _mca the first central magnetic path for a first alternating

magnetic flux

50, 51 formed by I _{_n} (ω = ω _n), the second central magnetic with respect to the first alternating

magnetic flux

50, 51 It is smaller than the second magnetic resistance R _mcb (ω = ω _n ) of the road. Therefore, as shown in FIG. 7, the first alternating

magnetic flux

50, 51 formed by the normal mode noise current I _n is mainly through the first central magnetic path.

Specifically, as shown in FIG. 7, the first alternating magnetic flux 50 formed by the normal mode noise current I _n flowing in the first coil 30, the first yoke 11, the first center leg 12 first It passes through a magnetic path formed by a first central magnetic path formed by a gap 17 and a second central magnetic leg 22, a second yoke 21, a third side magnetic leg 23, and a first side magnetic leg 13. First AC magnetic flux 51 formed by the normal mode noise current I _n flowing in the second coil 35, first yoke 11, formed by the first magnetic center leg 12 and the first gap 17 and the second magnetic center legs 22 It passes through a magnetic path formed by a first central magnetic path, a second yoke 21, a fourth side magnetic leg 24, and a second side magnetic leg 14.

On the other hand, _{the third reluctance R mca} (ω = 0) of the first central magnetic path with respect to the DC

magnetic fluxes

53 and 54 formed by _{the DC current I dc} is the second of the second central magnetic path with respect to the DC

magnetic fluxes

53 and 54. 4 Magnetic resistance is _{larger than R mcb} (ω = 0). Therefore, as shown in FIG. 8, the _{DC magnetic fluxes 53 and 54 formed by the DC current I dc} mainly pass through the second central magnetic path.

Specifically, as shown in FIG. 8, the _{DC magnetic flux 53 formed by the DC current I dc} flowing through the first coil 30 includes the first yoke 11, the second gap 43, the magnetic cylinder 40, and the third gap. It passes through a second central magnetic path formed by 44 and a magnetic path formed by a second yoke 21, a third side magnetic leg 23, and a first side magnetic leg 13. _{The DC magnetic flux 54 formed by the DC current I dc} flowing through the second coil 35 is a second central magnetic path formed by the first yoke 11, the second gap 43, the magnetic cylinder 40, and the third gap 44. 2 Passes through a magnetic path formed by a yoke 21, a fourth side magnetic leg 24, and a second side magnetic leg 14.

In this manner, in the dual-mode choke coil 1, the magnetic path of the first alternating

magnetic flux

50 and 51 which are formed by the normal mode noise current I _n, and the magnetic circuit of the DC

magnetic flux

53 and 54 are formed by the DC current I _dc Can be different. Therefore, even without increasing the first magnetic center leg 12 of the first gap length G ₁ of the first gap 17 between the second center leg 22, a first alternating current formed by the normal mode noise current I _n Magnetic saturation of the first magnetic core 10 (first central magnetic leg 12) and the second magnetic core 20 (second central magnetic leg 22) is less likely to occur with respect to the

magnetic fluxes

50 and 51. Since the first magnetic center leg 12 does not increase the first gap length G ₁ of the first gap 17 between the second central magnetic leg 22, reduction in the inductance of the dual-mode choke coil 1 is against the normal mode noise current I _n Can be suppressed. The decrease in impedance of the dual mode choke coil 1 with respect to the normal mode noise current can be suppressed.

As shown in FIG. 6, the normal mode noise current at a frequency Omega _n of the first alternating magnetic field formed by I _n, relative permeability mu _r10 of the first magnetic core 10 (ω = ω _n) and the second magnetic cores the 20 of relative permeability _{_{μ r20 (ω = ω n)}} , much greater than the vacuum of the relative permeability (= 1) to the first alternating magnetic field formed by the normal mode noise current I _n. Generally, the inductance of a magnetic core is proportional to the relative permeability of the magnetic core. Therefore, the first alternating

magnetic flux

50, 51 formed by the normal mode noise current I _n, the dual-mode choke coil 1 has a large inductance. The first alternating

magnetic flux

50, 51 formed by the normal mode noise current I _n, the dual-mode choke coil 1 has a large impedance. Dual-mode choke coil 1 attenuates the normal mode noise current I _n, it is possible to remove the normal mode noise current I _n.

In contrast, the common mode noise Denryu I _c is between Tadashigawa wire 4a and the ground, and propagates between the negative wire 4b and ground. The first winding direction of the first coil 30 is opposite to the second winding direction of the second coil 35. Therefore, common-mode noise current I _c from the inverter 8 (see FIG. 1) flows and a negative wire 4b which includes a positive-side wire 4a and the second coil 35 including the first coil 30 in the same direction. As shown in FIG. 9, the second alternating magnetic flux 56 formed by the common-mode noise current I _c, the first yoke 11, second side magnetic lead 14, the fourth side magnetic lead 24, the second yoke 21, the It passes through a magnetic path formed by the three-side magnetic leg 23 and the first side magnetic leg 13. However, the second AC magnetic flux 56 includes a first central magnetic path formed by the first central magnetic leg 12, the first gap 17, and the second central magnetic leg 22, the second gap 43, the magnetic cylinder 40, and the second. It does not pass through the second central magnetic path formed by the three gaps 44.

The normal mode noise current I _n and the common mode noise current I _c are generated by the switching operation of a plurality of switching elements included in the inverter 8 (see FIG. 1). _{Therefore, the frequency ω c} of the second AC magnetic field formed by the common mode noise current I _c is substantially equal to _{the frequency ω n} of the first AC magnetic field formed by the normal mode noise current I _n.

As shown in FIG. 6, at _{the frequency ω c} of the second AC magnetic field formed by _{the common mode noise current I c} _{, the relative permeability μ r10} (ω = ω _c ) of the first magnetic core 10 and the second magnetic core The relative magnetic permeability μ _r20 (ω = ω _c ) of 20 is much larger than the relative magnetic permeability (= 1) of the vacuum with respect to the second AC magnetic field formed by the common mode noise current I _c. Generally, the inductance of a magnetic core is proportional to the relative permeability of the magnetic core. Therefore, the dual mode choke coil 1 has a large inductance with respect to the second AC magnetic flux 56 formed by the common mode noise current I _c. The dual mode choke coil 1 has a large impedance with respect to the second AC magnetic flux 56 formed by the common mode noise current I _c. Therefore, the dual-mode choke coil 1 attenuates the common mode noise current I _c, can be removed common-mode noise current I _c.

The effect of the dual mode choke coil 1 of this embodiment will be described.
The dual mode choke coil 1 of the present embodiment can remove the normal mode noise current and the common mode noise current. The dual mode choke coil 1 includes a first magnetic core 10, a second magnetic core 20, a magnetic cylinder 40, a first coil 30, and a second coil 35. The first magnetic core 10 includes a first yoke 11, a first side magnetic leg 13, a second side magnetic leg 14, and a first central magnetic leg 12. The first side magnetic leg 13, the second side magnetic leg 14, and the first central magnetic leg 12 extend from the first yoke 11. The first central magnetic leg 12 is arranged between the first side magnetic leg 13 and the second side magnetic leg 14. The second magnetic core 20 includes a second yoke 21, a third side magnetic leg 23, a fourth side magnetic leg 24, and a second central magnetic leg 22. The third side magnetic leg 23, the fourth side magnetic leg 24, and the second central magnetic leg 22 extend from the second yoke 21. The second central magnetic leg 22 is arranged between the third side magnetic leg 23 and the fourth side magnetic leg 24. The first side magnetic leg 13 and the third side magnetic leg 23 are in contact with each other. The second side magnetic leg 14 and the fourth side magnetic leg 24 are in contact with each other. The first central magnetic leg 12 and the second central magnetic leg 22 are separated from each other with a first gap 17.

The first central magnetic leg 12 and the second central magnetic leg 22 are inserted into the magnetic cylinder 40 and separated from the magnetic cylinder 40. The magnetic cylinder 40 is separated from the first yoke 11 with a second gap 43. The magnetic cylinder 40 is separated from the second yoke 21 with a third gap 44. The first coil 30 is wound around the first side magnetic leg 13 and the third side magnetic leg 23. The second coil 35 is wound around the second side magnetic leg 14 and the fourth side magnetic leg 24. The first winding direction of the first coil 30 is opposite to the second winding direction of the second coil 35. The first reluctance of the first central magnetic path with respect to the AC magnetic flux is smaller than the second magnetic resistance of the second central magnetic path with respect to the AC magnetic flux. The AC magnetic flux is formed by the normal mode noise current flowing through the first coil 30 and the second coil 35. The third reluctance of the first central magnetic path with respect to the DC magnetic flux is larger than the fourth magnetic resistance of the second central magnetic path with respect to the DC magnetic flux. The direct current magnetic flux is formed by the direct current flowing through the first coil 30 and the second coil 35. The first central magnetic path is a magnetic path formed by the first central magnetic leg 12, the first gap 17, and the second central magnetic leg 22. The second central magnetic path is a magnetic path formed by the second gap 43, the magnetic cylinder 40, and the third gap 44.

Therefore, the magnetic path of the AC magnetic flux formed by the normal mode noise current can be made different from the magnetic path of the DC magnetic flux formed by the DC current. The first with respect to the AC magnetic flux formed by the normal mode noise current without increasing _{the first gap length G 1} of the first gap 17 between the first central magnetic leg 12 and the second central magnetic leg 22. Magnetic saturation of the magnetic core 10 and the second magnetic core 20 is less likely to occur. _{Since the first gap length G 1} of the first gap 17 between the first central magnetic leg 12 and the second central magnetic leg 22 is not increased, the decrease in the inductance of the dual mode choke coil 1 with respect to the normal mode noise current is suppressed. obtain. The decrease in impedance of the dual mode choke coil 1 with respect to the normal mode noise current can be suppressed. It is possible to suppress a decrease in the noise removing ability of the dual mode choke coil 1 with respect to the normal mode noise current.

In the dual mode choke coil 1 of the present embodiment, the first relative magnetic permeability (specific magnetic permeability μ _r10 (ω = ω _n )) of the first central magnetic leg 12 with respect to the AC magnetic field formed by the normal mode noise current, The second relative magnetic permeability (specific magnetic permeability μ _r20 (ω = ω _n )) of the second central magnetic leg 22 with respect to the AC magnetic field is the third relative magnetic permeability (specific magnetic permeability) of the magnetic cylinder 40 with respect to the AC magnetic field, respectively. Greater than μ _r40 (ω = ω _n )). The fourth specific magnetic permeability of the magnetic cylinder 40 with respect to the DC magnetic field (specific magnetic permeability μ _r40 (ω = 0)) is the fifth specific magnetic permeability of the first central magnetic _{leg 12 with respect to the DC magnetic field (specific magnetic permeability μ r10} (ω = 0)). = 0)) and larger than the sixth relative magnetic permeability of the second central magnetic _leg 22 with respect to the DC magnetic field (specific magnetic permeability μ r20 (ω = 0)).

Therefore, the magnetic path of the AC magnetic flux formed by the normal mode noise current can be made different from the magnetic path of the DC magnetic flux formed by the DC current. The magnetic saturation of the first magnetic core 10 and the second magnetic core 20 is less likely to occur with respect to the AC magnetic flux formed by the normal mode noise current. The decrease in impedance of the dual mode choke coil 1 with respect to the normal mode noise current can be suppressed. It is possible to suppress a decrease in the noise removing ability of the dual mode choke coil 1 with respect to the normal mode noise current.

In the dual mode choke coil 1 of the present embodiment, the first specific magnetic permeability (specific magnetic permeability μ _r10 (ω = ω _n )) and the second specific magnetic permeability (specific magnetic permeability μ _r20 (ω = ω _n )) are , Each is 10 times or more the third relative magnetic permeability (specific magnetic permeability μ _r40 (ω = ω _n )) and 10 times or more the seventh relative magnetic permeability of the vacuum with respect to the AC magnetic field. The 4th specific magnetic permeability (specific magnetic permeability μ _r40 (ω = 0)) is 10 times or more the 5th specific magnetic permeability (specific magnetic permeability μ _r10 (ω = 0)), and the 6th specific magnetic permeability (ratio). The magnetic permeability _{is 10 times or more of μ r20} (ω = 0)), and is 100 times or more of the eighth specific magnetic permeability of the vacuum with respect to the DC magnetic field. The fifth relative magnetic permeability μ _r10 (ω = 0) is 10 times or more the eighth specific magnetic permeability. The sixth relative magnetic permeability μ _r20 (ω = 0) is 10 times or more the eighth specific magnetic permeability.

In the dual mode choke coil 1 of the present embodiment, the fourth relative magnetic permeability (specific magnetic permeability μ _r40 (ω = 0)) is 1000 or more.

In the dual mode choke coil 1 of the present embodiment, the first specific magnetic permeability (specific magnetic permeability μ _r10 (ω = ω _n )) and the second specific magnetic permeability (specific magnetic permeability μ _r20 (ω = ω _n )) Is 100 or more, respectively.

In the dual mode choke coil 1 of the present embodiment, the first gap length G ₁ of the first gap 17 is the second gap length G _{2 of} the second gap 43 and the third gap length G _{3 of the third gap 44.} Greater than the sum.

Therefore, the equation (17) can be easily realized. The magnetic path of the AC magnetic flux formed by the normal mode noise current can be made different from the magnetic path of the DC magnetic flux formed by the DC current. The magnetic saturation of the first magnetic core 10 and the second magnetic core 20 is less likely to occur with respect to the AC magnetic flux formed by the normal mode noise current. The decrease in impedance of the dual mode choke coil 1 with respect to the normal mode noise current can be suppressed. It is possible to suppress a decrease in the noise removing ability of the dual mode choke coil 1 with respect to the normal mode noise current.

In the dual mode choke coil 1 of the present embodiment, the magnetic flux density of the DC magnetic flux in the magnetic cylinder 40 is smaller than the saturation magnetic flux density of the magnetic cylinder 40.

Therefore, magnetic saturation of the first magnetic core 10 and the second magnetic core 20 is less likely to occur with respect to the AC magnetic flux formed by the normal mode noise current. The decrease in impedance of the dual mode choke coil 1 with respect to the normal mode noise current can be suppressed. It is possible to suppress a decrease in the noise removing ability of the dual mode choke coil 1 with respect to the normal mode noise current.

In the dual mode choke coil 1 of the present embodiment, the saturation magnetic flux density of the magnetic cylinder 40 is 1.5 tesla or more.

Embodiment 2.
The dual mode choke coil 1b of the second embodiment will be described with reference to FIGS. 10 to 13. The dual-mode choke coil 1b of the present embodiment has the same configuration as the dual-mode choke coil 1 of the first embodiment, but is different from the dual-mode choke coil 1 of the first embodiment mainly in the following points. There is.

The dual mode choke coil 1b further includes a first non-magnetic spacer 46, a second non-magnetic spacer 47, and a third non-magnetic spacer 48. The first non-magnetic spacer 46, the second non-magnetic spacer 47, and the third non-magnetic spacer 48 are a resin such as an epoxy resin, a silicone resin, an acrylic resin, or an acrylonitrile butadiene styrene (ABS) copolymer resin, or a ceramic. Is formed of.

The first non-magnetic spacer 46 fills the second gap 43. The first non-magnetic spacer 46 is in contact with the magnetic cylinder 40 and the first yoke 11. Specifically, the first non-magnetic spacer 46 is in surface contact with the end surface 41 of the magnetic cylinder 40 and the surface of the first yoke 11 facing the end surface 41. The second non-magnetic spacer 47 fills the third gap 44. The second non-magnetic spacer 47 is in contact with the magnetic cylinder 40 and the second yoke 21. Specifically, the second non-magnetic spacer 47 is in surface contact with the end surface 42 of the magnetic cylinder 40 and the surface of the second yoke 21 facing the end surface 42.

The first non-magnetic spacer 46 can accurately define _{the second gap length G 2 of the second gap 43.} The second non-magnetic spacer 47 can accurately define _{the third gap length G 3 of the third gap 44.} The first non-magnetic spacer 46 and the second non-magnetic spacer 47 make it possible to accurately position the magnetic cylinder 40 with respect to the first magnetic core 10 and the second magnetic core 20.

The third non-magnetic spacer 48 is in contact with the inner surface 40b of the magnetic cylinder 40 and the side surface of the first central magnetic leg 12, and the inner surface 40b of the magnetic cylinder 40 and the second central magnetic leg 22. It is in contact with the side surface. The third non-magnetic spacer 48 enables the magnetic cylinder 40 to be accurately positioned with respect to the first central magnetic leg 12 of the first magnetic core 10 and the second central magnetic leg 22 of the second magnetic core 20. .. The third non-magnetic spacer 48 fills the first gap 17. The third non-magnetic spacer 48 can accurately define _{the first gap length G 1 of the first gap 17.} The third non-magnetic spacer 48 enables the first magnetic core 10 (first central magnetic leg 12) and the second magnetic core 20 (second central magnetic leg 22) to be accurately positioned with each other.

The effect of the dual mode choke coil 1b of the present embodiment has the following effects in addition to the effect of the dual mode choke coil 1 of the first embodiment.

The dual mode choke coil 1b of the present embodiment further includes a first non-magnetic spacer 46 and a second non-magnetic spacer 47. The first non-magnetic spacer 46 fills the second gap 43 and is in contact with the magnetic cylinder 40 and the first yoke 11. The second non-magnetic spacer 47 fills the third gap 44 and is in contact with the magnetic cylinder 40 and the second yoke 21.

Therefore, the magnetic cylinder 40 can be accurately positioned with respect to the first magnetic core 10 and the second magnetic core 20. It is possible to suppress a decrease in the noise removing ability of the dual mode choke coil 1b with respect to the normal mode noise current.

The dual mode choke coil 1b of the present embodiment further includes a third non-magnetic spacer 48. The third non-magnetic spacer 48 is in contact with the inner surface 40b of the magnetic cylinder 40 and the first side surface of the first central magnetic leg 12, and the inner surface 40b of the magnetic cylinder 40 and the second central magnetic leg 12 are in contact with each other. It is in contact with the second side surface of 22.

Therefore, the magnetic cylinder 40 can be accurately positioned with respect to the first central magnetic leg 12 of the first magnetic core 10 and the second central magnetic leg 22 of the second magnetic core 20. It is possible to suppress a decrease in the noise removing ability of the dual mode choke coil 1b with respect to the normal mode noise current.

In the dual mode choke coil 1b of the present embodiment, the third non-magnetic spacer 48 fills the first gap 17.

Therefore, the first magnetic core 10 (first central magnetic leg 12) and the second magnetic core 20 (second central magnetic leg 22) can be accurately positioned with each other. It is possible to suppress a decrease in the noise removing ability of the dual mode choke coil 1b with respect to the normal mode noise current.

It should be considered that the first and second embodiments disclosed this time are exemplary in all respects and not restrictive. The scope of the present disclosure is indicated by the scope of claims rather than the above description, and is intended to include all modifications within the meaning and scope of the claims.

1,1b dual mode choke coil, 2 power converter, 3 DC power supply, 4a positive wire, 4b negative wire, 5, 6a, 6b capacitor, 7 earth, 8 inverter, 9 load, 10 first magnetic core, 11 1st yoke, 12 1st central magnetic leg, 12a end face, 13 1st side magnetic leg, 13a end face, 14 2nd side magnetic leg, 14a end face, 17 1st gap, 20 2nd magnetic core, 21 2nd yoke, 22 2nd central magnetic leg, 22a end face, 23 3rd side magnetic leg, 23a end face, 24 4th side magnetic leg, 24a end face, 30 1st coil, 31, 32 terminals, 35 2nd coil, 36, 37 terminals, 40 magnetic cylinder, 40a outer surface, 40b inner surface, 41, 42 end face, 43 second gap, 44 third gap, 46 first non-magnetic spacer, 47 second non-magnetic spacer, 48 third non-magnetic spacer, 50 , 51 1st AC magnetic flux, 53, 54 DC magnetic flux, 56 2nd AC magnetic flux.

Claims

A dual mode choke coil capable of removing a normal mode noise current and a common mode noise current, wherein the dual mode choke coil is
With the first magnetic core
With the second magnetic core
Magnetic cylinder and
With the first coil
Equipped with a second coil
The first magnetic core includes a first yoke, a first side magnetic leg, a second side magnetic leg, and a first central magnetic leg, and the first side magnetic leg, the second side magnetic leg, and the above. The first central magnetic leg extends from the first yoke, and the first central magnetic leg is arranged between the first side magnetic leg and the second side magnetic leg.
The second magnetic core includes a second yoke, a third side magnetic leg, a fourth side magnetic leg, and a second central magnetic leg, and the third side magnetic leg, the fourth side magnetic leg, and the above. The second central magnetic leg extends from the second yoke, and the second central magnetic leg is arranged between the third side magnetic leg and the fourth side magnetic leg.
The first side magnetic leg and the third side magnetic leg are in contact with each other.
The second side magnetic leg and the fourth side magnetic leg are in contact with each other.
The first central magnetic leg and the second central magnetic leg are separated from each other with a first gap.
The first central magnetic leg and the second central magnetic leg are inserted into the magnetic cylinder and separated from the magnetic cylinder.
The magnetic cylinder is separated from the first yoke with a second gap.
The magnetic cylinder is separated from the second yoke with a third gap.
The first coil is wound around the first side magnetic leg and the third side magnetic leg.
The second coil is wound around the second side magnetic leg and the fourth side magnetic leg.
The first winding direction of the first coil is opposite to the second winding direction of the second coil.
The first magnetic resistance of the first central magnetic path with respect to the AC magnetic flux is smaller than the second magnetic resistance of the second central magnetic path with respect to the AC magnetic flux, and the AC magnetic flux flows through the first coil and the second coil. Formed by modal noise current,
The third magnetic resistance of the first central magnetic path with respect to the DC magnetic flux is larger than the fourth magnetic resistance of the second central magnetic path with respect to the DC magnetic flux, and the DC magnetic flux flows through the first coil and the second coil. Formed by DC current,
The first central magnetic path is a magnetic path formed by the first central magnetic leg, the first gap, and the second central magnetic leg.
The second central magnetic path is a dual mode choke coil which is a magnetic path formed by the second gap, the magnetic cylinder, and the third gap.
The first relative magnetic permeability of the first central magnetic leg with respect to the AC magnetic field formed by the normal mode noise current and the second relative magnetic permeability of the second central magnetic leg with respect to the AC magnetic field are the AC magnetic fields, respectively. Greater than the third relative magnetic permeability of the magnetic cylinder with respect to
The fourth relative magnetic permeability of the magnetic cylinder with respect to the DC magnetic field is larger than the fifth relative magnetic permeability of the first central magnetic leg with respect to the DC magnetic field, and the sixth ratio of the second central magnetic leg with respect to the DC magnetic field. The dual mode choke coil according to claim 1, which is larger than the magnetic permeability.
The first specific magnetic permeability and the second specific magnetic permeability are each 10 times or more the third specific magnetic permeability and 10 times or more the seventh specific magnetic permeability of the vacuum with respect to the AC magnetic field.
The 4th specific magnetic permeability is 10 times or more the 5th specific magnetic permeability, 10 times or more the 6th specific magnetic permeability, and 100 times the 8th specific magnetic permeability of the vacuum with respect to the DC magnetic field. That's it,
The fifth relative magnetic permeability is 10 times or more the eighth specific magnetic permeability.
The dual mode choke coil according to claim 2, wherein the sixth relative magnetic permeability is 10 times or more the eighth specific magnetic permeability.
The dual mode choke coil according to claim 2 or 3, wherein the fourth relative magnetic permeability is 1000 or more.
The dual mode choke coil according to any one of claims 2 to 4, wherein the first specific magnetic permeability and the second specific magnetic permeability are 100 or more, respectively.
The first gap length of the first gap is larger than the sum of the second gap length of the second gap and the third gap length of the third gap, according to any one of claims 1 to 5. Dual mode choke coil.
The dual mode choke coil according to any one of claims 1 to 6, wherein the magnetic flux density of the DC magnetic flux in the magnetic cylinder is smaller than the saturation magnetic flux density of the magnetic cylinder.
The dual mode choke coil according to claim 7, wherein the saturation magnetic flux density is 1.5 tesla or more.
The magnetic cylinder is made of rolled steel for general structure, silicon steel plate or permalloy.
The dual mode choke coil according to any one of claims 1 to 8, wherein the first magnetic core and the second magnetic core are a ferrite core, an amorphous core, or an iron dust core.
A first non-magnetic spacer that fills the second gap and is in contact with the magnetic cylinder and the first yoke.
The dual according to any one of claims 1 to 9, further comprising a second non-magnetic spacer in contact with the magnetic cylinder and the second yoke by filling the third gap. Mode choke coil.
The dual mode choke coil according to claim 10, wherein the first non-magnetic spacer and the second non-magnetic spacer are made of resin or ceramic.
The inner surface of the magnetic cylinder is in contact with the first side surface of the first central magnetic leg, and the inner surface of the magnetic cylinder is in contact with the second side surface of the second central magnetic leg. The dual mode choke coil according to any one of claims 1 to 11, further comprising a third non-magnetic spacer.
The dual mode choke coil according to claim 12, wherein the third non-magnetic spacer fills the first gap.
The dual mode choke coil according to claim 12 or 13, wherein the third non-magnetic spacer is made of resin or ceramic.