JP7328815B2 - magnetically coupled inductor - Google Patents

Description

The present invention relates to magnetically coupled inductors.

Conventionally, there has been proposed a magnetically coupled inductor in which coils are wound around both ends of an annular core and a separate or integrated common core is provided in the center (see Patent Documents 1 and 2, for example). In such a magnetically coupled inductor, the two cores around which the coil is wound are arranged in parallel at the ends of each other, and a common core is provided between the two cores, resulting in an increase in size. there were. Moreover, since the two coils are separated from each other, it is difficult to increase the degree of coupling.

Therefore, a magnetically coupled inductor in which two coils are arranged so that their coil axes are aligned has also been proposed (see Patent Document 3, for example). According to this magnetically coupled inductor, it is possible not only to reduce the distance between the two coils, but also to adjust the degree of coupling by arranging a separate spacer between the two coils.

JP 2017-192206 A Japanese Patent No. 5784601 JP 2018-190823 A

However, the magnetically coupled inductor described in Patent Literature 3 has to prepare a separate spacer, spread the spacer wider than the flange, and attach it to the winding core, which cannot be said to have good workability.

SUMMARY OF THE INVENTION The present invention has been made to solve such conventional problems, and its object is to provide a magnetically coupled inductor capable of suppressing an increase in size and suppressing a decrease in workability in adjusting the degree of coupling. is to provide

A magnetically coupled inductor according to the present invention is a magnetically coupled inductor having a first coil and a second coil that are magnetically coupled to each other, and has a first winding core around which the first coil is wound and the first coil. A first main core portion having two first sidewalls formed along the axial direction of the winding core and opposed to each other, and a first stopper wall extending in a direction toward each other from the two first sidewalls, and the second coil. Two second side walls facing each other and having a second core to be wound and formed along the axial direction of the second core, and a second stopper wall extending from the two second side walls in a direction approaching each other. a second main core portion assembled to the first main core portion such that the axes of the first winding core and the second winding core are aligned; and the first main core portion and the second a common core portion having a substantially U-shaped hollowed-out U-shaped portion that is attached to the assembled body in which the two main core portions are assembled and that is adjacent to the first winding core and the second winding core; , wherein the assembly has a gap in which the first winding core and the second winding core are not in contact with each other, and when the common core portion is attached to the assembly, the U-shaped has a gap without being in contact with both the first winding core and the second winding core, and the common core portion includes both end surfaces formed on both end side sides of the U-shaped portion and the both end surfaces and a locking projection protruding from the mounting surface, wherein the first stopper wall and the second stopper wall straddle the first stopper wall and the second stopper wall, and the locking projection can be locked. The both end surfaces of the common core portion are in contact with the first stopper wall and the second stopper wall in a state in which the locking protrusion is locked in the mounting groove.

According to the present invention, the second main core portion is attached to the first main core portion so that the axes of the first winding core and the second winding core are aligned. In addition to reducing the distance between the two coils by aligning the axes, for example, by combining a plurality of types of first and second main core portions, the first core and the second core can be combined. The degree of coupling (mutual inductance) can also be adjusted by adjusting the gap distance. Therefore, it is possible to suppress an increase in size and to suppress a decrease in workability in adjusting the degree of coupling.

1 is a perspective view showing the configuration of a magnetically coupled inductor according to an embodiment of the invention; FIG. 1 is an exploded perspective view showing the configuration of a magnetically coupled inductor according to an embodiment of the present invention; FIG. 1 is a top view showing the configuration of a magnetically coupled inductor according to an embodiment of the invention; FIG. 4 is a top view showing a partial configuration of the magnetically coupled inductor shown in FIG. 3; FIG. FIG. 2 is a front view showing a partial configuration shown in FIG. 1; 1 is a first circuit diagram showing an application example of a magnetically coupled inductor according to this embodiment; FIG. FIG. 4 is a second circuit diagram showing an application example of the magnetically coupled inductor according to the present embodiment; FIG. 4 is a third circuit diagram showing an application example of the magnetically coupled inductor according to the present embodiment; FIG. 11 is a fourth circuit diagram showing an application example of the magnetically coupled inductor according to this embodiment; 9 is a timing chart showing how the first to fourth switching elements shown in FIGS. 7 and 8 are controlled; FIG. FIG. 10 is a circuit diagram showing an equivalent circuit of the magnetically coupled inductor shown in FIGS. 6 to 9; FIG. FIG. 2 is a conceptual diagram showing the magnetic flux of the magnetically coupled inductor according to this embodiment;

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below along with preferred embodiments. It should be noted that the present invention is not limited to the embodiments described below, and can be modified as appropriate without departing from the gist of the present invention. In addition, in the embodiments shown below, there are places where illustrations and explanations of some configurations are omitted, but the details of the omitted technologies are as long as there is no contradiction with the contents explained below. Needless to say, well-known or well-known techniques are applied as appropriate.

FIG. 1 is a perspective view showing the configuration of a magnetically coupled inductor according to an embodiment of the invention, and FIG. 2 is an exploded perspective view showing the configuration of a magnetically coupled inductor according to an embodiment of the invention. 3 is a top view showing the configuration of a magnetically coupled inductor according to an embodiment of the present invention, and FIG. 4 is a top view showing a partial configuration of the magnetically coupled inductor shown in FIG.

As shown in FIGS. 1 to 4, the magnetically coupled inductor 1 according to this embodiment has a first coil L1 and a second coil L2 that are magnetically coupled to each other. In addition to L2, a first main core portion 10, a second main core portion 20, and a common core portion 30 are provided.

The first main core portion 10 is made of ferrite and includes an outer frame 11 and a first winding core 12 . The outer frame 11 is a substantially U-shaped frame member in which one end wall 11a and two side walls 11b and 11c are connected at right angles. The first winding core 12 is a cylindrical member that protrudes from the end wall 11a of the outer frame 11 to the U-shaped open side. A first coil L<b>1 is wound around the first winding core 12 . As shown in FIG. 2, both ends of the first coil L1 are connected to terminals, for example (illustration is omitted except in FIG. 2).

The second main core portion 20 is a member formed symmetrically with the first main core portion 10 . The second main core portion 20 is also made of ferrite and has an outer frame 21 and a second winding core 22 . The outer frame 21 is a substantially U-shaped frame member in which one end wall 21a and two side walls 21b and 21c are connected at right angles. The second winding core 22 is a cylindrical member that protrudes from the end wall 21a of the outer frame 21 toward the U-shaped open side. A second coil L2 is wound around the second winding core 22 as described above. Both ends of the second coil L2 are also connected to terminals, for example, as shown in FIG. 2 (illustration is omitted except in FIG. 2).

Here, the first main core portion 10 and the second main core portion 20 are assembled together in a state in which the first coil L1 and the second coil L2 are wound around the first winding core 12 and the second winding core 22. . At this time, the first main core portion 10 and the second main core portion 20 are assembled so that the U-shaped open sides of the outer frames 11 and 21 are in contact with each other. In the assembly AB formed by assembling the first main core portion 10 and the second main core portion, the central axes of the first core 12 and the second core 22 are aligned. Further, in the assembly AB, the first winding core 12 and the second winding core 22 are not in contact with each other and have a gap S1 (see FIG. 4).

Furthermore, the first main core portion 10 is provided with stopper walls 13 and 14 . The stopper walls 13 and 14 are provided at one ends of the two side walls 11b and 11c, respectively, and extend from the one ends of the two side walls 11b and 11c in a substantially perpendicular direction and in directions approaching each other.

Like the first main core portion 10, the second main core portion 20 is also provided with stopper walls 23 and 24, and the stopper walls 23 and 24 extend from one end of the two side walls 21b and 21c in a direction substantially perpendicular to each other. extending in the direction of approach.

FIG. 5 is a front view showing a partial configuration shown in FIG. 1, removing the second main core portion 20 (including the second coil L2) from the magnetically coupled inductor 1, and showing the front view from the opposite side of the end wall 11a. It shows the viewed state.

As shown in FIGS. 2 and 5, the common core portion 30 is a substantially U-shaped plate material in plan view, and is made of ferrite or a dust core. The common core portion 30 has a U-shaped portion (concave portion) 30a formed by hollowing out a sheet of plate material in a substantially U-shape. Further, the common core portion 30 has a first locking projection 31 and a second locking projection 32 at both ends of the U shape.

In addition, as shown in FIG. 4, the assembly AB has two attachments for attaching the common core portion 30 (see FIG. 4) to an intermediate position between the first main core portion 10 and the second main core portion 20. It has grooves (mounted portions) MG1 and MG2.

Specifically, the first mounting groove MG1 is provided across the first stopper wall 13 of the first main core portion 10 and the first stopper wall 23 of the second main core portion 20 . A portion MG1a on the side of the first stopper wall 13 and a portion MG1b on the side of the first stopper wall 23 of the first mounting groove MG1 have a symmetrical structure, and have a structure in which the first locking projection 31 is fitted. . Similarly, the second attachment groove MG2 is provided across the second stopper wall 14 of the first main core portion 10 and the second stopper wall 24 of the second main core portion 20 . A portion MG2a on the side of the second stopper wall 14 and a portion MG2b on the side of the second stopper wall 24 in the second mounting groove MG2 have a symmetrical structure, and have a structure in which the second locking projection 32 is fitted. .

Here, the common core portion 30 is in a state in which the first locking projection 31 and the second locking projection 32 are attached to the two mounting grooves MG1 and MG2 (in a state of being attached to the assembly AB). The U-shaped end faces 33, 34 come into contact with the respective stopper walls 13, 14 (23, 24) (see FIG. 5).

In addition, when the common core portion 30 is attached to the assembly AB, the arc portion 30b of the U-shaped portion 30a does not come into contact with the first core 12 (and the second core 22). S2.

Here, in this embodiment, a plurality of types of the first main core portion 10 and the second main core portion 20 are prepared. The plurality of types of the first main core portion 10 and the second main core portion 20 have different lengths of the first winding core 12 and the second winding core 22, respectively, and have the same dimensions for other configurations. . Therefore, by selecting a combination of the first main core portion 10 and the second main core portion 20 from a plurality of types, it is possible to adjust the distance of the gap S1 between the first core 12 and the second core 22. It has become. Therefore, the degree of coupling (leakage inductance) of the magnetically coupled inductor 1 according to this embodiment can be adjusted by selecting from a plurality of types.

Similarly, in this embodiment, a plurality of types of common core portions 30 are prepared. In the common core portion 30, the diameter of the arc portion 30b of the U-shaped portion 30a differs for each type, and the dimensions of the other configurations are the same. Therefore, by selecting one of a plurality of types of common core portions 30, it is possible to adjust the distance of the gap S2 between the U-shaped portion 30a and the first core 12 and the second core 22. . Therefore, the magnetically coupled inductor 1 according to this embodiment can adjust the degree of coupling (mutual inductance) by selecting from a plurality of types.

The magnetically coupled inductor 1 is constructed by assembling a first main core portion 10 around which the first coil L1 is wound and a second main core portion 20 around which the second coil L2 is wound. After the common core portion 30 is attached to the assembled body AB, it is housed in a predetermined case (not shown) having a size to accommodate them. A predetermined case is filled with a potting agent. Further, such a magnetically coupled inductor 1 may be mounted on heat radiation fins via an insulating sheet.

6 to 9 are circuit diagrams showing application examples of the magnetically coupled inductor 1 according to this embodiment. 6 to 9, for the sake of convenience of explanation, some parts are given the same reference numerals, but they do not necessarily have to be the same.

As shown in FIG. 6, the magnetically coupled inductor 1 according to this embodiment is applied to, for example, an interleaved PFC circuit. Specifically, the interleaved PFC circuit includes an AC power supply AC, six diodes D1 to D6, a magnetically coupled inductor 1, a capacitor Ca, and first and third switching elements Q1 and Q3.

The AC power supply AC has one end connected to the connection point a and the other end connected to the connection point b. A connection point a connects the anode of the first diode D1 and the cathode of the second diode D2. A connection point b connects the anode of the third diode D3 and the cathode of the fourth diode D4.

The cathode of the first diode D1 and the cathode of the third diode D3 are connected at a connection point c. The connection point c is connected to one end of the first coil L1 and one end of the second coil L2 of the magnetically coupled inductor 1 shown in FIG. 1 and the like. The other end of the first coil L1 is connected to the anode of the fifth diode D5. The other end of the second coil L2 is connected to the anode of the sixth diode D6.

The first and third switching elements Q1 and Q3 are each composed of an N-channel MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor). The gate G of the first switching element Q1 is connected to the control device, and the drain D is connected to the connection point d between the other end of the second coil L2 and the anode of the sixth diode D6. The gate G of the third switching element Q3 is connected to the control device, and the drain D is connected to the connection point e between the other end of the first coil L1 and the anode of the fifth diode D5.

The cathode of the fifth diode D5 and the cathode of the sixth diode D6 are connected at the connection point f. The connection point f is connected to the first output terminal OUT1 and to one end of the capacitor Ca. The other end of the capacitor Ca is connected to the second output terminal OUT2, the source S of the first switching element Q1, the source S of the third switching element Q3, the anode of the second diode D2, and the anode of the fourth diode D4. It is connected to the.

Further, as shown in FIG. 7, the magnetically coupled inductor 1 according to this embodiment may be applied to, for example, an interleaved Totem Pole PFC circuit. Specifically, the interleaved Totem Pole PFC circuit includes an AC power supply AC, a magnetically coupled inductor 1, first to sixth switching elements Q1 to Q6, and a capacitor Ca.

The AC power supply AC has one end connected to the connection point a and the other end connected to the connection point b. The connection point a is connected to one end of the first coil L1 and one end of the second coil L2 of the magnetically coupled inductor 1 shown in FIG. 1 and the like. The other end of the first coil L1 is connected to the connection point c. The other end of the second coil L2 is connected to the connection point d.

Each of the first to sixth switching elements Q1 to Q6 is composed of an N-channel MOSFET. Gates G of the first to sixth switching elements Q1 to Q6 are connected to a control device.

The drains D of the first, third and fifth switching elements Q1, Q3, Q5 are connected to the first output terminal OUT1 and to one end of the capacitor Ca. The sources S of the first, third and fifth switching elements Q1, Q3 and Q5 are connected to the connection point c, the connection point d and the connection point b, respectively.

The drains D of the second, fourth and sixth switching elements Q2, Q4 and Q6 are connected to the connection point c, the connection point d and the connection point b, respectively. The sources S of the second, fourth and sixth switching elements Q2, Q4, Q6 are connected to the second output terminal OUT2 and the other end of the capacitor Ca.

Further, as shown in FIG. 8, the magnetically coupled inductor 1 according to this embodiment may be applied to, for example, an AC inverter circuit. Specifically, the AC inverter circuit includes a DC power source DC, a magnetically coupled inductor 1, first to sixth switching elements Q1 to Q6, and a capacitor Ca.

Each of the first to sixth switching elements Q1 to Q6 is composed of an N-channel MOSFET. Gates G of the first to sixth switching elements Q1 to Q6 are connected to a control device.

A direct current power supply DC has a positive electrode connected to a connection point a and a negative electrode connected to a connection point b. The connection point a is connected to one end of the capacitor Ca and to the drains D of the first, third and fifth switching elements Q1, Q3 and Q5. The connection point b is connected to the other end of the capacitor Ca and to the sources S of the second, fourth and sixth switching elements Q2, Q4 and Q6.

The sources S of the first, third and fifth switching elements Q1, Q3 and Q5 are connected to the drains of the second, fourth and sixth switching elements Q2, Q4 and Q6 via connection points c, d and e, respectively. It is connected.

The connection point c is connected to one end of the second coil L2 of the magnetically coupled inductor 1 shown in FIG. 1 and the like. The connection point d is connected to one end of the first coil L<b>1 of the magnetically coupled inductor 1 . The other end of the first coil L1 and the other end of the second coil L2 are connected to one end of the load M, and the other end of the load M is connected to the connection point e.

Further, as shown in FIG. 9, the magnetically coupled inductor 1 according to this embodiment may be applied to, for example, a boost converter circuit. Specifically, the boost converter circuit includes first and second capacitors Ca1 and Ca2, a magnetically coupled inductor 1, first and third switching elements Q1 and Q3, and first and second diodes D1 and D2. ing.

First, the connection point a is connected to the first input terminal IN1 and to one end of the first capacitor Ca1. Further, the connection point a is connected to one end of the first coil L1 and one end of the second coil L2 of the magnetically coupled inductor 1 shown in FIG. 1 and the like. The connection point b is connected to the second input terminal IN2 and the other end of the first capacitor Ca1.

The other end of the first coil L1 is connected to the anode of the first diode D1. The other end of the second coil L2 is connected to the anode of the second diode D2. The first and third switching elements Q1 and Q3 are each composed of an N-channel MOSFET. The gate G of the first switching element Q1 is connected to the control device, and the drain D is connected to the connection point c between the other end of the second coil L2 and the anode of the second diode D2. The gate G of the third switching element Q3 is connected to the control device, and the drain D is connected to the connection point d between the other end of the first coil L1 and the anode of the first diode D1.

A cathode of the first diode D1 and a cathode of the second diode D2 are connected at a connection point e. The connection point e is connected to the first output terminal OUT1 and to one end of the second capacitor Ca2. The other end of the second capacitor Ca2 is connected to the second output terminal OUT2, the source S of the first switching element Q1, the source S of the third switching element Q3, and the connection point b.

FIG. 10 is a timing chart showing how the first to fourth switching elements Q1 to Q4 shown in FIGS. 7 and 8 are controlled. In the magnetically coupled inductor 1 shown in the circuit examples of FIGS. 7 and 8, the phases are shifted by 180° so that currents alternately flow through the two coils L1 and L2. This is because the output ripple current can be reduced. In order to realize such control, the first to fourth switching elements Q1 to Q4 are turned on and off as shown in FIG.

As shown in FIG. 10, the first switching element Q1 and the second switching element Q2 are turned on and off synchronously in opposite phases. Similarly, the third switching element Q3 and the fourth switching element Q4 are turned on and off synchronously in opposite phases. In addition, the first switching element Q1 and the third switching element Q3 are turned on and off with a phase shift of approximately 180°. The second switching element Q2 and the fourth switching element Q4 are also turned on and off with a phase shift of approximately 180°.

Although illustration is omitted, the first switching element Q1 and the third switching element Q3 are similarly on/off controlled in the circuit examples shown in FIGS. 6 and 9 to reduce the ripple current.

FIG. 11 is a circuit diagram showing an equivalent circuit of the magnetically coupled inductor 1 shown in FIGS. 6-9. Since the magnetically coupled inductor 1 has leakage inductance components L1' and L2' for the first coil L1 and the second coil L2, it can be expressed as an equivalent circuit shown in FIG.

In particular, in the magnetically coupled inductor 1 according to the present embodiment, the diameter of the arc portion 30b (the distance of the gap S2) is adjusted by selecting one of the plurality of types of common core portions 30, and the leakage inductance component L1 ', L2' can be adjusted. As a result, the degree of coupling can also be adjusted.

FIG. 12 is a conceptual diagram showing the magnetic flux of the magnetically coupled inductor 1 according to this embodiment. A magnetic flux shown in FIG. 12 is generated by the flow of current. This magnetic flux generates mutual inductance in the two coils L1 and L2. This mutual inductance can be adjusted by adjusting the distance of the gap S1, and as a result, the degree of coupling can also be adjusted.

In this manner, according to the magnetically coupled inductor 1 according to the present embodiment, the second main core portion 20 is arranged so that the axes of the first winding core 12 and the second winding core 22 are aligned. 10, the axes of the first coil L1 and the second coil L2 are aligned to reduce the distance between the two coils L1 and L2. The degree of coupling (mutual inductance) can also be adjusted by adjusting the distance of the gap S1 between the first winding core 12 and the second winding core 22 depending on the combination of the portion 10 and the second main core portion 20 . Therefore, it is possible to suppress an increase in size and to suppress a decrease in workability in adjusting the degree of coupling.

Further, when the common core portion 30 is attached, the U-shaped portion 30a does not come into contact with both the first winding core 12 and the second winding core 22 and has a gap S2. By preparing a plurality of types of core portions 30 and selecting and attaching them, the distance of the gap S2 can be adjusted, and the degree of coupling (leakage inductance) can also be adjusted.

Further, since the mounting grooves MG1 and MG2 are provided for mounting the common core portion 30 at an intermediate position between the first main core portion 10 and the second main core portion 20, the common core portion 30 can be attached to the first main core portion 10 and the second main core portion 20. It is possible to prevent the mounting of the two main core portions 20 from being greatly biased toward one of them.

The present invention has been described above based on the embodiments, but the present invention is not limited to the above embodiments, and modifications may be made without departing from the scope of the present invention, and well-known and publicly known techniques may be used. May be combined.

For example, in the present embodiment, the common core portion 30 is not limited to the shape described above, and may be composed of, for example, two or more members. In particular, when it is composed of two or more members, for example, two plate members having arc portions 30b are assembled together to surround the entire circumferences of the first core 12 and the second core 22. may be

In addition, the common core portion 30 is attached so as to be inserted from one direction into the outer frames 11 and 21 of the first main core portion 10 and the second main core portion 20, but is not limited to this. It may be assembled from another direction. For example, when the side walls 11b, 21b of the outer frames 11, 21 are opened and closed via hinges, the common core portion 30 may be attached from the side.

Further, the materials of the first main core portion 10, the second main core portion 20 and the common core portion 30 are not limited to those described above, and other materials can be appropriately selected. Therefore, the first main core portion 10 and the second main core portion 20 may be made of different materials.

Reference Signs List 1: magnetically coupled inductor 10: first main core portion 12: first winding core 20: second main core portion 22: second winding core 30: common core portion 30a: U-shaped portion (recess)
30b: Arc portion AB: Assembled body L1: First coil L2: Second coils MG1, MG2: Mounting groove (mounted portion)
S1: Gap S2: Gap

Claims (1)

A magnetically coupled inductor having a first coil and a second coil that are magnetically coupled to each other,
It has a first winding core around which the first coil is wound, and two first sidewalls formed along the axial direction of the first winding core and facing each other, and a direction approaching each other from the two first sidewalls a first main core portion having an extending first stop wall ;
It has a second core around which the second coil is wound, and two second side walls are formed along the axial direction of the second core and face each other. a second main core portion having an extending second stopper wall and assembled to the first main core portion so that the axes of the first core and the second core are aligned;
U that is hollowed out in a substantially U shape that is attached to the assembled body in which the first main core portion and the second main core portion are assembled and that is adjacent to the first winding core and the second winding core and a common core portion having a character portion,
The assembled body has a gap without the first winding core and the second winding core being in contact with each other,
When the common core portion is attached to the assembly, the U-shaped portion has a gap without being in contact with both the first winding core and the second winding core,
The common core portion has both end faces formed on both end sides of the U-shaped portion and locking projections projecting from the both end faces,
The first stopper wall and the second stopper wall have a mounting groove that straddles the first stopper wall and the second stopper wall and that can be locked by the locking projection,
Both end surfaces of the common core contact the first stopper wall and the second stopper wall in a state in which the locking projection is locked in the mounting groove.
A magnetically coupled inductor characterized by:

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