Common mode reactor

Abstract

The invention provides a common-mode reactor which comprises a first coil, a second coil, an I-shaped iron core and an E-shaped iron core, the first coil and the second coil are wound on a middle column of the E-shaped iron core in parallel in the same direction and the same number of turns, and the I-shaped iron core is connected with an opening of the E-shaped iron core. By means of the technical scheme, the technical problem that in the prior art, the differential-mode current magnetic field offset effect and the common-mode current suppression effect of a common-mode reactor are poor can be solved.

Description

Technical Field

[0001] The invention relates to the technical field of electromagnetic induction, and in particular to a common mode reactor. Background Art

[0002] Common mode reactors are usually used in switching power supplies of electronic equipment to filter common mode electromagnetic interference signals. The two coils are wound on the same core, with the same number of turns and phase, and are wound in opposite directions.

[0003] When the differential mode current in the circuit flows through the common mode inductor, the current generates opposite magnetic fields in the inductor coils wound in the same phase, which cancel each other out and do not affect the passage of the differential mode current.

[0004] When the common-mode current in the circuit flows through the common-mode inductor, due to the isotropic nature of the common-mode current, a magnetic field in the same direction will be generated in the coil, increasing the inductive reactance of the coil, making the coil appear as high impedance, producing a strong damping effect, thereby attenuating the common-mode current and achieving the purpose of filtering. However, when the common-mode current is large, the common-mode reactance will have a large leakage inductance, and the common-mode current suppression effect will deteriorate.

[0005] The common mode reactor used in the prior art usually has coils wound on both sides of the magnetic core, with the two coils being wound in opposite directions. Fig.11 and Fig.12 As shown. When the differential mode operating current i a 、i b When the current flows through coil 1# 11 and coil 2# 12 respectively, magnetic fields that cancel each other out are generated. At this time, the normal signal current is mainly affected by the coil resistance and a small amount of damping caused by leakage inductance. When common-mode current flows through the coil, due to the isotropic nature of the common-mode current, a magnetic field in the same direction is generated in the coil, increasing the inductive reactance of the coil, thereby suppressing the common-mode current.

[0006] like Fig.11 and Fig.12 As shown, when the current i flowing through coil 1# 11 and coil 2# 12 a 、i b When it is larger, the magnetic flux φ a1 +φ a2 and φ b1 +φ b2 , where φ a1 With φ b1 i a 、i b The main magnetic flux generated, φ a2 With φ b2 i a 、i b The leakage flux generated.

[0007] when i a 、i bWhen it is a differential mode current, Fig.11 As shown, the magnetic field in the core cancels out, and the residual magnetic flux is φ a1 +φ a2 -(φ b1 +φ b2 ), in general, the main magnetic flux φ a1 With φ b1 However, due to the core structure problem, the common mode reactor has a large leakage flux and the leakage flux φ a2 With φ b2 Therefore, there is some magnetic flux in the iron core that cannot be offset, and then there is damping, which leads to poor magnetic field offset effect of differential mode current and obstruction of the passage of differential mode current.

[0008] when i a 、i b When it is a common mode current, Fig.12 As shown, the magnetic fields in the iron core are superimposed, but due to the magnetic leakage phenomenon, the magnetic flux enclosed by the two coils is smaller than φ a1 +φ a2 +(φ b1 +φ b2 ), the increase in coil inductance is reduced, which leads to imperfect suppression of common-mode current. Summary of the invention

[0009] The present invention aims to solve at least one of the technical problems existing in the prior art.

[0010] The invention provides a common mode reactor, which comprises: a first coil, a second coil, an I-type iron core and an E-type iron core. The first coil and the second coil are wound in parallel on a center column of the E-type iron core in the same direction and with the same number of turns. The I-type iron core is connected to the opening of the E-type iron core.

[0011] Furthermore, the common mode reactor also includes a first coil outlet copper bar, a first coil inlet copper bar, a second coil outlet copper bar and a second coil inlet copper bar. The first coil outlet copper bar and the first coil inlet copper bar are respectively connected to the two ends of the first coil, and the second coil outlet copper bar and the second coil inlet copper bar are respectively connected to the two ends of the second coil.

[0012] Furthermore, the common mode reactor also includes a coil support plate, which is ring-shaped and sleeved on the middle column of the E-shaped iron core. The coil support plate is used to provide support for the first coil and the second coil.

[0013] Furthermore, the common mode reactor also includes a mounting base plate, and the E-shaped iron core is fixed on the mounting base plate.

[0014] By applying the technical solution of the present invention, a common-mode reactor is provided. The common-mode reactor is formed by winding the first coil and the second coil in parallel with the same direction and the same number of turns on the middle column of the E-type iron core, and using the I-type iron core to block the opening of the E-type iron core, so that the main magnetic flux and the leakage magnetic flux generated by the coil are completely surrounded in the coil, offsetting the leakage magnetic flux generated by the differential mode current, reducing the damping, and improving the passability of the differential mode current; when the common mode current is large, the common mode reactor will not have a large leakage magnetic flux phenomenon, and the common mode current suppression effect is better. Compared with the prior art, the technical solution of the present invention can solve the technical problems of poor differential mode current magnetic field offset effect and poor common mode current suppression effect of the common mode reactor in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The included drawings are used to provide a further understanding of the embodiments of the present invention, which constitute a part of the specification, are used to illustrate the embodiments of the present invention, and together with the text description, explain the principles of the present invention. Obviously, the drawings in the following description are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0016] Figure 1 A schematic diagram of the three-dimensional structure of a common-mode reactor provided according to a specific embodiment of the present invention is shown;

[0017] Figure 2 An exploded view of the structure of a common mode reactor provided according to a specific embodiment of the present invention is shown;

[0018] Figure 3 A schematic front view of a common mode reactor provided according to a specific embodiment of the present invention is shown;

[0019] Figure 4 Shown along Figure 3 Sectional view along line AA;

[0020] Figure 5 Shown along Figure 4 Sectional view along the midline BB;

[0021] Figure 6 A schematic diagram showing the principle of differential mode current magnetic field cancellation of a common mode reactor provided in a specific embodiment of the present invention is shown;

[0022] Figure 7 A schematic diagram showing the common-mode current suppression principle of a common-mode reactor provided according to a specific embodiment of the present invention is shown;

[0023] Figure 8 A schematic diagram of the application connection of a common mode reactor provided in a specific embodiment of the present invention is shown;

[0024] Fig. 9A schematic diagram of a voltage waveform at the input end of a common-mode reactor provided according to a specific embodiment of the present invention is shown;

[0025] Fig.10 A schematic diagram of a current waveform at the output end of a common-mode reactor provided according to a specific embodiment of the present invention is shown;

[0026] Fig.11 A schematic diagram showing the principle of differential mode current magnetic field cancellation in the prior art is shown;

[0027] Fig.12 The schematic diagram of the common mode current suppression principle in the prior art is shown.

[0028] The above drawings include the following reference numerals:

[0029] 1. First coil; 2. Second coil; 3. I-type iron core; 4. E-type iron core; 5. First coil outlet copper bar; 6. First coil inlet copper bar; 7. Second coil outlet copper bar; 8. Second coil inlet copper bar; 9. Coil support plate; 10. Mounting base plate; 11. 1# coil; 12. 2# coil. DETAILED DESCRIPTION

[0030] It should be noted that, in the absence of conflict, the embodiments in this application and the features in the embodiments can be combined with each other. The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0032] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps set forth in these embodiments do not limit the scope of the present invention. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to actual proportional relationships. The technology, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be considered as a part of the specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values.

[0033] like Figures 1 to 10 As shown, according to a specific embodiment of the present invention, a common-mode inductor is provided, which includes: a first coil 1, a second coil 2, an I-type iron core 3 and an E-type iron core 4, the first coil 1 and the second coil 2 are wound in parallel on the middle column of the E-type iron core 4 in the same direction and with the same number of turns, and the I-type iron core 3 is connected to the opening of the E-type iron core 4.

[0034] By applying this configuration, a common-mode reactor is provided. The common-mode reactor is formed by winding the first coil 1 and the second coil 2 in parallel in the same direction and with the same number of turns on the middle column of the E-type iron core 4, and using the I-type iron core 3 to block the opening of the E-type iron core 4, so that the main magnetic flux and leakage magnetic flux generated by the coil are completely surrounded in the coil, offsetting the leakage magnetic flux generated by the differential mode current, reducing the damping, and improving the passability of the differential mode current; when the common mode current is large, the common mode reactor will not have a large leakage magnetic flux phenomenon, and the common mode current suppression effect is better. Compared with the prior art, the technical solution of the present invention can solve the technical problems of poor differential mode current magnetic field offset effect and poor common mode current suppression effect of the common mode reactor in the prior art.

[0035] With this configuration, when the current i flowing through the first coil 1 and the second coil 2 a and i b When it is larger, the magnetic flux φ a1 +φ a2 and φ b1 +φ b2 , where φ a1 and φ b1 i a and i b The main magnetic flux generated, φ a2 and φ b2 i a and i b The leakage flux generated.

[0036] when i a and i b When it is a differential mode current, Figure 6 As shown, the magnetic field surrounded by the coil cancels out, and the residual magnetic flux is φa1 +φ a2 -(φ b1 +φ b2 ). Since the coils are wound at the same position and the structure of the common mode reactor E-type core 4 is symmetrical, that is, the magnetic field is symmetrical, the main magnetic flux and leakage magnetic flux generated by the two coils are almost the same, so it can be considered that φ a1 +φ a2 -(φ b1 +φ b2 )≈0, so the magnetic flux surrounded by the two coils is almost completely offset, and there is no damping.

[0038] The magnetic field cancellation effect of differential mode current is better, and the differential mode current has good permeability.

[0039] when i a and i b When it is a common mode current, Figure 7 As shown, the magnetic field in the core is superimposed. Since the coils are wound at the same position and the structure of the common mode reactor E-type core 4 is symmetrical, that is, the magnetic field is symmetrical, the leakage flux is also surrounded by the two coils, so the magnetic flux surrounded by the two coils is φ a1 +φ a2 +(φ b1 +φ b2 ). The coil inductance increases, and the suppression effect of common mode current is better.

[0040] As a specific embodiment of the present invention, Figure 4 As shown, in order to facilitate the import and export of the first coil 1 and the second coil 2, the configurable common mode inductor also includes a first coil outlet copper bar 5, a first coil inlet copper bar 6, a second coil outlet copper bar 7 and a second coil inlet copper bar 8. The first coil outlet copper bar 5 and the first coil inlet copper bar 6 are respectively connected to the two ends of the first coil 1, and the second coil outlet copper bar 7 and the second coil inlet copper bar 8 are respectively connected to the two ends of the second coil 2.

[0041] Further, in the present invention, if Figure 1 and Figure 2 As shown, in order to prevent the displacement of the coil and affect the use effect during the use of the reactor, the common-mode reactor can be configured to also include a coil support plate 9, which is annular and sleeved on the middle column of the E-type iron core 4. The coil support plate 9 is used to provide support for the first coil 1 and the second coil 2.

[0042] In addition, in the present invention, if Figure 1 and Figure 2As shown, in order to facilitate the installation and fixation of the common mode reactor, the configurable common mode reactor also includes a mounting base plate 10, and the E-type iron core 4 is fixed on the mounting base plate 10. As a specific embodiment of the present invention, the mounting base plate 10 has a plurality of mounting holes and can be fixed to other components by matching fixings.

[0043] The two groups of coils of the novel common-mode inductor of the present invention are wound in the same direction at the same position at the same time, with the same number of turns, and the coil winding is simple. The leakage flux generated by the two groups of coils is also completely surrounded by the coils, that is, the leakage flux of the first coil 1 is surrounded by the second coil 2, and similarly, the leakage flux of the second coil 2 is also surrounded by the first coil 1. The main magnetic flux and leakage magnetic flux generated by the two groups of coils of the common-mode inductor are completely surrounded by the coils, and there will be no leakage magnetic flux outside the coils to affect the use effect. The leakage magnetic flux generated by the differential mode current is offset, the damping is reduced, and the differential mode current passability is good. When the common mode current is large, the common mode reactance will not have the phenomenon of large leakage magnetic flux, and the common mode current suppression effect is better. Since the leakage magnetic flux does not affect the use effect, the efficiency of the common mode inductor of the present invention is higher than that of the existing inductor.

[0044] The novel common-mode reactor of the present invention is mostly used in power supply circuits, the power supply end is connected to the two coil input ends of the common-mode reactor of the present invention, and the two coil output ends are connected to the load circuit. When the common-mode noise signal at the power supply end passes through the common-mode reactor, the common-mode noise signal will be filtered out and blocked outside the load circuit, achieving the effect of suppressing the common-mode current.

[0045] In order to further understand the present invention, the following Figures 1 to 10 The common mode reactor of the present invention will be described in detail.

[0046] like Figures 1 to 10 As shown, according to a specific embodiment of the present invention, a common mode reactor is provided, which includes: a first coil 1, a second coil 2, an I-type iron core 3, an E-type iron core 4, a first coil outlet copper bar 5, a first coil inlet copper bar 6, a second coil outlet copper bar 7, a second coil inlet copper bar 8, a coil support plate 9 and a mounting base plate 10. The first coil 1 and the second coil 2 are wound in parallel on the middle column of the E-type iron core 4 in the same direction and with the same number of turns, and the I-type iron core 3 is connected to the opening of the E-type iron core 4.

[0047] The first coil outlet copper bar 5 and the first coil inlet copper bar 6 are respectively connected to the two ends of the first coil 1 , and the second coil outlet copper bar 7 and the second coil inlet copper bar 8 are respectively connected to the two ends of the second coil 2 .

[0048] The coil support plate 9 is annular and sleeved on the middle column of the E-shaped iron core 4. The coil support plate 9 is used to provide support for the first coil 1 and the second coil 2. The E-shaped iron core 4 is fixed on the mounting base plate 10.

[0049] like Figure 8As shown, the novel common-mode reactor of the present invention can be used in a power supply circuit, the power supply end is connected to the copper bar at the input end of the two coils of the novel reactor, and the copper bar at the output end of the two coils is connected to the load circuit. When the common-mode noise signal at the power supply end passes through the novel reactor, the common-mode noise signal will be filtered out and blocked outside the load circuit, achieving the effect of suppressing the common-mode current.

[0050] Fig. 9 and Fig.10 A specific embodiment is provided, such as Fig. 9 As shown, the input differential mode voltage reference frequency is 5kHz and the amplitude is 5V. The two input reference voltages contain three common mode harmonic components: 1V / 10kHz, 0.5V / 25kHz, and 0.3V / 35kHz. After passing through the common mode reactor of the present invention, the output current does not contain common mode components, the common mode suppression effect is better, and the differential mode current passing performance is better. Fig.10 shown.

[0051] In summary, the present invention provides a common-mode reactor, which winds the first coil and the second coil in parallel with the same direction and number of turns on the middle column of the E-type iron core, uses an I-type iron core to block the opening of the E-type iron core, and completely surrounds the main magnetic flux and leakage magnetic flux generated by the coil in the coil, offsets the leakage magnetic flux generated by the differential mode current, reduces damping, and improves the passability of the differential mode current; when the common mode current is large, the common mode reactor will not have a large leakage magnetic flux phenomenon, and the common mode current suppression effect is better. Compared with the prior art, the technical solution of the present invention can solve the technical problems of poor differential mode current magnetic field offset effect and poor common mode current suppression effect of the common mode reactor in the prior art.

[0052] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0053] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A common mode reactor, characterized in that: The common mode reactor comprises: a first coil (1), a second coil (2), an I-type iron core (3) and an E-type iron core (4); the first coil (1) and the second coil (2) are wound in parallel on a center column of the E-type iron core (4) in the same direction and with the same number of turns; the I-type iron core (3) is connected to an opening of the E-type iron core (4).

2. The common mode reactor according to claim 1, characterized in that: The common-mode reactor further comprises a first coil outlet copper bar (5), a first coil inlet copper bar (6), a second coil outlet copper bar (7) and a second coil inlet copper bar (8); the first coil outlet copper bar (5) and the first coil inlet copper bar (6) are respectively connected to two ends of the first coil (1); the second coil outlet copper bar (7) and the second coil inlet copper bar (8) are respectively connected to two ends of the second coil (2).

3. The common mode reactor according to claim 1 or 2, characterized in that: The common-mode reactor also includes a coil support plate (9), which is ring-shaped and sleeved on the middle column of the E-shaped iron core (4). The coil support plate (9) is used to provide support for the first coil (1) and the second coil (2).

4. The common mode reactor according to any one of claims 1 to 3, characterized in that: The common mode reactor also includes a mounting base plate (10), and the E-shaped iron core (4) is fixed on the mounting base plate (10).

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