Common-mode and differential-mode combined anti-interference circuit

Abstract

The utility model discloses a common-mode and differential-mode combined anti-interference circuit, which belongs to the technical field of power electronics and comprises a primary common-mode filter circuit, a differential-mode filter circuit and a secondary common-mode filter circuit. Wherein the power supply input end is connected with the power supply output end after sequentially passing through the primary common-mode filter circuit, the differential-mode filter circuit and the secondary common-mode filter circuit, and the differential-mode filter circuit is an LC filter circuit. Comprising a first differential mode inductor, a second differential mode inductor, a first differential mode capacitor, a second differential mode capacitor, a third differential mode capacitor, a fourth differential mode capacitor, a fifth differential mode capacitor and a sixth differential mode capacitor. Compared with the prior art, the circuit adopts the combined design of two stages of common-mode filter circuits and one stage of differential-mode filter circuit in the middle, can effectively reduce the output noise interference of the power supply, meets the design requirements of electromagnetic compatibility, and can inhibit the conduction common-mode interference of the switching power supply of 0.15 MHz to 30 MHz.

Description

TECHNICAL FIELD

[0001] The utility model belongs to power electronics technical field, especially relates to a common mode and differential mode combined anti-interference circuit. BACKGROUND

[0002] In switching power supply, frequency converter and other power electronic equipment, the coupling inhibition of high frequency conducted interference and near field radiation interference is the core problem of electromagnetic compatibility design. The prior art usually adopts the filter architecture of discrete common mode reactor or differential mode capacitor combination, and the independently arranged common mode suppression unit or differential mode suppression unit in the above prior art has problems of impedance characteristic mismatch, high frequency attenuation blind area and space electromagnetic coupling, especially cannot effectively inhibit 0.15MHz~30MHz switching power supply conducted common mode interference.

[0003] In military power supply assembly, the military standard is harsh, and dependence on foreign special integrated chip should be reduced as far as possible. Therefore, how to design a common mode and differential mode combined anti-interference circuit to solve the above technical problems has long plagued the technical personnel in the field. SUMMARY

[0004] In view of the above technical problems, the utility model provides a common mode and differential mode combined anti-interference circuit, which adopts the combined design of two-stage common mode filter circuit, intermediate addition of one-stage differential mode filter circuit.

[0005] The utility model solves the above problems through the following technical means:

[0006] A common mode and differential mode combined anti-interference circuit, characterized by comprising one-stage common mode filter circuit, differential mode filter circuit and two-stage common mode filter circuit, wherein: the power input end is connected with the power output end after passing through one-stage common mode filter circuit, differential mode filter circuit and two-stage common mode filter circuit in sequence; the differential mode filter circuit is LC filter circuit, comprising first differential mode inductor, second differential mode inductor, first differential mode capacitor, second differential mode capacitor, third differential mode capacitor, fourth differential mode capacitor, fifth differential mode capacitor and sixth differential mode capacitor, the first differential mode inductor and the second differential mode inductor are respectively connected in series on the positive circuit and the negative circuit of the power, the first differential mode capacitor is connected in parallel at the front end node of the first differential mode inductor and the second differential mode inductor, the second differential mode capacitor is connected in parallel at the rear end node of the first differential mode inductor and the second differential mode inductor, the third differential mode capacitor and the fourth differential mode capacitor are connected in series and then connected in parallel with the first differential mode capacitor, and the fifth differential mode capacitor and the sixth differential mode capacitor are connected in series and then connected in parallel with the second differential mode capacitor.

[0007] Preferably, the middle connection of the third differential mode capacitor and the fourth differential mode capacitor is grounded.

[0008] Preferably, the middle connection of the fifth differential mode capacitor and the sixth differential mode capacitor is grounded.

[0009] Preferably, the primary common mode filter circuit comprises a front-end filter inductor and a front-end impedance capacitor, wherein the front-end impedance capacitor is connected in parallel to the power input end, and the front-end filter inductor is connected in series to the power circuit.

[0010] Preferably, the primary common mode filter circuit comprises a front-end filter inductor and a front-end impedance capacitor, wherein the front-end impedance capacitor is connected in parallel to the power input end, and the front-end filter inductor is connected in series to the power circuit.

[0011] Preferably, the primary common mode filter circuit comprises a front-end filter inductor and a front-end impedance capacitor, wherein the front-end impedance capacitor is connected in parallel to the power input end, and the front-end filter inductor is connected in series to the power circuit.

[0012] The common-mode and differential-mode combined anti-interference circuit has the following beneficial effects:

[0013] 1) The circuit adopts a two-stage common mode filter circuit and a combined design of an intermediate first-stage differential mode filter circuit, can effectively reduce power output noise interference and meet electromagnetic compatibility design requirements, and can suppress 0.15MHz-30MHz switching power supply conducted common mode interference.

[0014] 2) The circuit can reduce the dependence of the circuit on foreign special power supply chips by using multiple domestic discrete devices. The circuit uses discrete devices to achieve the required functions, ensures the stability and reliability of the product, and controls the cost to easily achieve.

[0015] 3) The special shell used in the circuit has a compact structure and good sealing performance, and can be stacked and fitted on a circular pipe body, and is particularly suitable for narrow spaces on a missile. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical scheme of the present application, the following will briefly introduce the drawings needed in the embodiments. Obviously, the drawings described below are only some embodiments of the present application, and other drawings can also be obtained according to these drawings without creative labor.

[0017] Figure 1 is a schematic diagram of the overall circuit of the present application;

[0018] Figure 2 is the installation schematic diagram of the utility model;

[0019] Figure 3 is the shell schematic diagram of the utility model.

[0020] Wherein, 1-circuit board, 101-wiring hole, 102-mounting groove, 103-power output port, 104-power input port, 2-shell, 3-cover. DETAILED DESCRIPTION

[0021] In the description of the utility model, it needs to understand that the orientation or position relation indicated by the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like is the orientation or position relation based on the shown in the drawings, and is only for the convenience of describing the utility model and simplifying the description, and therefore cannot be understood as the restriction on the utility model. The terms "first", "second" are only for the description purpose, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features limited by "first", "second" can be explicitly or implicitly included one or more features. In the description of the utility model, the meaning of "multiple" is two or more, unless otherwise specified.

[0022] The utility model will be described in detail below in combination with the drawings.

[0023] As Figure 1 shown, the common-mode and differential-mode combined anti-interference circuit includes a first common-mode filter circuit, a differential-mode filter circuit and a second common-mode filter circuit, wherein: the power input end is connected with the power output end after passing through the first common-mode filter circuit, the differential-mode filter circuit and the second common-mode filter circuit in sequence; the differential-mode filter circuit is an LC filter circuit, including a first differential-mode inductor L1, a second differential-mode inductor L2, a first differential-mode capacitor C1, a second differential-mode capacitor C2, a third differential-mode capacitor C3, a fourth differential-mode capacitor C4, a fifth differential-mode capacitor C5 and a sixth differential-mode capacitor C6, the first differential-mode inductor L1 and the second differential-mode inductor L2 are respectively connected in series on the positive circuit and the negative circuit of the power supply, the first differential-mode capacitor C1 is connected in parallel at the front end node of the first differential-mode inductor L1 and the second differential-mode inductor L2, the second differential-mode capacitor C2 is connected in parallel at the rear end node of the first differential-mode inductor L1 and the second differential-mode inductor L2, the third differential-mode capacitor C3 and the fourth differential-mode capacitor C4 are connected in series and then connected in parallel with the first differential-mode capacitor C1, the fifth differential-mode capacitor C5 and the sixth differential-mode capacitor C6 are connected in series and then connected in parallel with the second differential-mode capacitor C2.

[0024] In this embodiment, the middle connection of the third differential mode capacitor C3 and the fourth differential mode capacitor C4 is grounded. The middle connection of the fifth differential mode capacitor C5 and the sixth differential mode capacitor C6 is grounded. In addition, the first-order common-mode filter circuit includes a front-end filter inductor L3 and a front-end impedance capacitor C7, wherein: the front-end impedance capacitor C7 is connected in parallel at the power input end, and the front-end filter inductor L3 is connected in series on the power supply circuit. The first-order common-mode filter circuit includes a rear-end filter inductor L4 and a rear-end impedance capacitor C8, wherein: the rear-end impedance capacitor C8 is connected in parallel at the power output end, and the rear-end filter inductor L4 is connected in series on the power supply circuit.

[0025] In actual implementation, the front-end impedance capacitor C7 and the rear-end impedance capacitor C8 are low equivalent series impedance capacitors with a capacity range of 0.01uF-0.47uF, mainly used to filter out common-mode interference. The first differential mode inductor L1 and the second differential mode inductor L2 are selected to be a filter with a common-mode impedance greater than 500Ω at a frequency of 100MHz, and the capacities of the third differential mode capacitor C3 and the fourth differential mode capacitor C4 and the fifth differential mode capacitor C5 and the sixth differential mode capacitor C6 are selected to be 0.01uF / 1Kv, connected across the input+ and input- ends, and the midpoint of the capacitor is grounded to the shell. The circuit has been verified by mature project tests and can effectively suppress 0.15MHz-30MHz switching power supply conducted common-mode interference.

[0026] It should be noted that the first differential mode inductor L1 and the second differential mode inductor L2 at both ends are used to filter out common-mode noise and prevent high-frequency common-mode interference from entering or leaving the power module. The differential mode filter circuit in the middle uses L and C filtering, selects 0.1-2.2uH inductance and 1-100uF capacitance, and can effectively filter out the reflected ripple at the input end of the conversion circuit. The entire circuit combines common-mode and differential-mode filtering to comprehensively reduce electromagnetic interference.

[0027] As shown in Figure 2 and Figure 3 , it further comprises a circuit board 1, a shell 2 and a cover 3 for installing the common-differential mode combined anti-interference circuit, wherein: the middle part of the circuit board 1 is provided with a wiring hole 101, one side of the circuit board 1 is provided with a mounting groove 102, and the other side of the circuit board 1 is provided with a power output port 103 and a power input port 104; the bottom of the shell 2 is provided with a hollow boss with the same size as the wiring hole 101, the edge of the hollow boss is arranged with a sealing ring, and one side of the shell 2 is provided with an open cavity with the same size as the mounting groove 102; the middle part of the cover 3 is provided with a center hole with the same size as the wiring hole 101, and one side of the cover 3 is provided with a slot with the same size as the mounting groove 102; the cover 3 and the shell 2 are detachably connected through screws; and the sealed cavities formed by the plurality of shells 2 and covers 3 can be stacked and fitted on the circular pipe body. In the figure, the special shell used by the circuit has a compact structure and good sealing performance, and can be stacked and fitted on the circular pipe body, and is particularly suitable for use in narrow spaces on missiles.

[0028] Finally, it should be noted that: the above examples are used to illustrate the technical solutions of the present application, but not limited to; although the present application is described in detail with reference to the foregoing examples, those skilled in the art should understand that: it can still be modified to the technical solutions recorded in the foregoing examples, or part of the technical features are replaced; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A common-differential mode combination anti-jamming circuit, characterized by, The application relates to a power supply anti-interference circuit, which comprises a primary common-mode filter circuit, a differential-mode filter circuit and a secondary common-mode filter circuit. The power supply input end is connected with the power supply output end through the primary common-mode filter circuit, the differential-mode filter circuit and the secondary common-mode filter circuit. The differential-mode filter circuit is an LC filter circuit, which comprises a first differential-mode inductor (L1), a second differential-mode inductor (L2), a first differential-mode capacitor (C1), a second differential-mode capacitor (C2), a third differential-mode capacitor (C3), a fourth differential-mode capacitor (C4), a fifth differential-mode capacitor (C5) and a sixth differential-mode capacitor (C6). The first differential-mode inductor (L1) and the second differential-mode inductor (L2) are respectively connected in series on the positive circuit and the negative circuit of the power supply. The first differential-mode capacitor (C1) is connected in parallel at the front end node of the first differential-mode inductor (L1) and the second differential-mode inductor (L2). The second differential-mode capacitor (C2) is connected in parallel at the rear end node of the first differential-mode inductor (L1) and the second differential-mode inductor (L2). The third differential-mode capacitor (C3) and the fourth differential-mode capacitor (C4) are connected in series and then connected in parallel with the first differential-mode capacitor (C1). The fifth differential-mode capacitor (C5) and the sixth differential-mode capacitor (C6) are connected in series and then connected in parallel with the second differential-mode capacitor (C2).

2. The common-differential mode combination anti-jamming circuit according to claim 1, characterized in that, The middle connecting position of the third differential-mode capacitor (C3) and the fourth differential-mode capacitor (C4) is connected with the ground.

3. The common-differential mode combination anti-jamming circuit according to claim 1, characterized in that, The middle connecting position of the fifth differential-mode capacitor (C5) and the sixth differential-mode capacitor (C6) is connected with the ground.

4. The common-differential mode combination anti-jamming circuit according to claim 1, characterized in that, The primary common-mode filter circuit comprises a front-end filter inductor (L3) and a front-end impedance capacitor (C7). The front-end impedance capacitor (C7) is connected in parallel at the power supply input end, and the front-end filter inductor (L3) is connected in series on the power supply circuit.

5. The common-differential mode combination anti-jamming circuit according to claim 1, characterized in that, The primary common-mode filter circuit comprises a rear-end filter inductor (L4) and a rear-end impedance capacitor (C8). The rear-end impedance capacitor (C8) is connected in parallel at the power supply output end, and the rear-end filter inductor (L4) is connected in series on the power supply circuit.

6. The common-differential mode combination anti-jamming circuit according to claim 1, characterized in that, The application further comprises a circuit board (1), a shell (2) and a cover (3) for installing the common differential-mode combined anti-interference circuit. The middle part of the circuit board (1) is provided with a wiring hole (101), one side of the circuit board (1) is provided with a mounting groove (102), and the other side of the circuit board (1) is provided with a power supply output port (103) and a power supply input port (104). The bottom of the shell (2) is provided with a hollow boss with the same size as the wiring hole (101), the edge of the hollow boss is provided with a sealing ring, and one side of the shell (2) is provided with an open cavity with the same size as the mounting groove (102). The middle part of the cover (3) is provided with a center hole with the same size as the wiring hole (101), and one side of the cover (3) is provided with a slot with the same size as the mounting groove (102). The cover (3) and the shell (2) are detachably connected through screws. The sealing cavities formed by the plurality of shells (2) and covers (3) can be stacked on the circular pipe body.

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