CN211453828U - Conduction noise detection device - Google Patents
Conduction noise detection device Download PDFInfo
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- CN211453828U CN211453828U CN201922447472.2U CN201922447472U CN211453828U CN 211453828 U CN211453828 U CN 211453828U CN 201922447472 U CN201922447472 U CN 201922447472U CN 211453828 U CN211453828 U CN 211453828U
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Abstract
The utility model discloses a conduction noise detection device, which comprises a signal input end, a differential mode noise detection circuit, a common mode noise detection circuit and a signal output end; the input ends of a first transmission line and a second transmission line of a transmission line transformer of the differential mode noise detection circuit are respectively connected with a live line and a zero line, and the output ends of the first transmission line and the second transmission line are grounded through a first resistor; the output end of the first transmission line is also connected with the signal output end; the first transmission line and the second transmission line are both connected with a grounding capacitor; the input ends of a first inductor and a second inductor of the common mode noise detection circuit are respectively connected with a zero line and a live line, and the output ends of the common mode noise detection circuit are both connected with a second resistor and are connected with a signal output end through the second resistor; the differential mode noise detection circuit and the common mode noise detection circuit are both connected with the selection switch; the selection switch is connected with the signal output end. The utility model discloses can carry out quick accurate differentiation with common mode interference form, differential mode interference form and common mode differential mode mixed interference form.
Description
Technical Field
The utility model relates to an electromagnetic compatibility detects technical field, specifically is a conduction noise detection device.
Background
Electromagnetic compatibility refers to the comprehensive evaluation of the interference level (EMI) and the anti-interference capability (EMS) of electronic products in terms of electromagnetic fields, and is one of the most important indexes of product quality. In the frequency band of 9KHz-30MHz of electronic and electric products, the power supply conducts and emits electromagnetic noise interference in three main forms, namely a common mode interference form, a differential mode interference form and a common mode and differential mode mixed interference form.
The technical means for solving the problem of power transmission interference is to adopt a matched power filter to perform noise suppression, and it is very necessary to fully understand and master the interference form of power transmission electromagnetic noise before designing the power filter or power filter circuit of electronic and electric products. In practical work, engineers usually need to continuously test and eliminate to finally confirm the interference mode if the interference property of the power supply conducted electromagnetic noise is determined to be a common-mode interference mode, a differential interference mode or a mixed interference mode of the common mode and the differential mode, and the mode has large workload and low accuracy of test data.
SUMMERY OF THE UTILITY MODEL
The utility model discloses to the problem that above-mentioned prior art exists, provide a conduction noise detection device.
In order to achieve the above purpose, the utility model discloses a following technical scheme realizes:
a conducted noise detection device comprises a signal input end, a differential mode noise detection circuit, a common mode noise detection circuit, a signal selection switch and a signal output end;
the input ends of a first transmission line and a second transmission line of a transmission line transformer of the differential mode noise detection circuit are respectively connected with a live line and a zero line, and the output ends of the first transmission line and the second transmission line are grounded through a first resistor; the output end of the first transmission line is also connected with a signal output end; the first transmission line and the second transmission line are both connected with a grounding capacitor;
the input ends of a first inductor and a second inductor of the common mode noise detection circuit are respectively connected with a zero line and a live line, and the output ends of the common mode noise detection circuit are both connected with a second resistor and are connected with a signal output end through the second resistor; the input ends of the first inductor and the second inductor are connected with each other through a second capacitor, and the output ends of the first inductor and the second inductor are connected with each other through a third capacitor;
the differential mode noise detection circuit and the common mode noise detection circuit are both connected with the selection switch; the selection switch is connected with the signal output end.
Furthermore, the live wire and the zero wire are both connected with a first capacitor; the first capacitor has filtering and coupling functions.
Further, the device also comprises an output protection circuit; the output protection circuit comprises a third inductor and a fourth capacitor; and one end of each of the third inductor and the fourth capacitor is connected with the signal output end, and the other end of each of the third inductor and the fourth capacitor is grounded.
Further, the first resistor and the second resistor are both precision resistors.
Furthermore, the signal output end is the same shaft end as the signal output end.
The utility model has the advantages that:
1. the common-mode interference form, the differential-mode interference form and the common-mode and differential-mode mixed interference form can be rapidly and accurately distinguished.
2. The input and output safety output protection circuit is provided, so that not only the detection device can be protected, but also the receiver can be protected.
3. The detection result can be output only by shifting the selection switch, the use is convenient, and the circuit is simple and easy to manufacture.
Drawings
Fig. 1 is a schematic block diagram of a circuit structure of the conducted noise detecting apparatus of the present invention;
fig. 2 is a schematic diagram of a circuit structure of the conducted noise detecting apparatus of the present invention;
FIG. 3 is a schematic diagram of the structure of the differential mode noise detection circuit of the present invention;
fig. 4 is a schematic diagram of the structure of the common mode noise detection circuit of the present invention.
In the figure: 1-a first capacitor, 2-a transmission line transformer, 3-a grounding capacitor, 4-a first resistor, 5-a first inductor, 6-a second inductor, 7-a second capacitor, 8-a second resistor, 9-another second resistor, 10-a third capacitor, 11 a selective switch, 12-a third inductor, 13-a fourth capacitor and 14-a signal output coaxial end.
Detailed Description
The technical solution in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.
Please refer to fig. 1-2, which are a schematic block diagram and a schematic structural diagram of a conducted noise detection apparatus according to the present invention. The device aims to provide a detection device for separating differential mode signals and common mode signals, which assists testers to quickly judge the types of interference signals and further manufactures a filtering circuit for filtering corresponding noise.
Referring to fig. 1, the conducted noise detection apparatus of the present invention is composed of a signal input terminal, a differential mode noise detection circuit, a common mode noise detection circuit, a signal selection switch 11, an output protection circuit, and a signal output terminal.
Referring to fig. 2, the device to be detected is connected to the live line L, the zero line N and the ground line GND of the signal input terminal, the live line L and the zero line N are both connected to the first capacitor 1, and the first capacitor 1 has signal isolation and coupling functions, so that not only the dc voltage in the input signal can be filtered, but also the detection device can be better coupled to the conducted noise detection apparatus.
The differential mode noise detection circuit comprises a transmission line transformer 2, a grounded capacitor 3 and a first resistor 4.
One end of a first transmission line of the transmission line transformer 2 is connected with the live wire L, the other end of the first transmission line is connected with the signal output end, and the first transmission line is grounded through a first resistor 4; one end of a second transmission line of the transmission line transformer 2 is connected with the zero line N, and the other end of the second transmission line is grounded through a first resistor 4. The first transmission line and the second transmission line of the transmission line transformer 2 are both connected with a grounding capacitor 3 which plays a role of filtering. The first resistor 4 is a precision resistor.
The common mode noise detection circuit comprises a first inductor 5, a second inductor 6, a second capacitor 7 and a second resistor 8.
One end of the first inductor 5 is connected with a zero line N of a signal input end, the other end of the first inductor is connected with a signal output end through the second resistor 8, one end of the second inductor 6 is connected with a live line L of the signal input end, the other end of the second inductor is connected with the signal output end through the other second resistor 9, two ends of the second capacitor 7 are respectively connected with an input end of the first inductor 5 and an input end of the second inductor 6, two ends of the third capacitor 10 are respectively connected with an output end of the first inductor 5 and an output end of the second inductor 6, and the second capacitor 7 and the third capacitor 10 play a role in isolation. The second resistor 8 and the further second resistor 9 are precision resistors.
The differential mode noise detection circuit and the common mode noise detection circuit are both connected with the selection switch 11, and the noise output type is selected through the selection switch 11.
The output end is provided with an output protection circuit, the output protection circuit comprises a third inductor 12 and a fourth capacitor 13, one end of each of the third inductor 12 and the fourth capacitor 13 is connected with the same shaft end 14 of the signal output, and the other end of each of the third inductor 12 and the fourth capacitor 13 is connected with the ground. The signal output coaxial terminal 14 is connected to the receiver.
The working principle and the using method are as follows:
according to the basic definition of common-mode and differential-mode currents: the common mode signal current ICM is characterized by a noise current to and from L, N and ground at the same amplitude and phase; the differential mode current IDM is characterized by noise currents that travel between L, N and are in opposite phase.
Referring to fig. 3, the first transmission line and the second transmission line of the transmission line transformer 2 form a common mode choke coil, which filters the common mode signal current between the live line L and the ground line, and between the neutral line N and the ground line, as shown by the dotted line in the figure, the common mode signal current is finally grounded through the resistor 4, and the differential mode signal current is output through the signal output coaxial end 14.
Referring to fig. 4, the first inductor 5 and the second inductor 6 form a differential mode choke coil, which filters out the differential mode signal current between the live line L and the neutral line N, as shown by the dotted line in the figure, and the common mode signal current is output through the signal output coaxial terminal 14.
The signal source is connected to the input end and then is connected to the power supply, the noise test is selected by shifting the selection switch 11, and if the noise output exists after the corresponding circuit is connected to the switch, the signal source is proved to have the noise, so that the use is convenient and the operation is simple.
The foregoing is a more detailed description of the present invention, taken in conjunction with the specific preferred embodiments thereof, and it is not intended that the invention be limited to the specific embodiments shown and described. To the utility model belongs to the technical field of ordinary technical personnel, do not deviate from the utility model discloses under the prerequisite of design, can also make a plurality of simple deductions or replacement, all should regard as belonging to the utility model discloses a protection scope.
Claims (5)
1. A conducted noise detecting apparatus, characterized in that: the device comprises a signal input end, a differential mode noise detection circuit, a common mode noise detection circuit, a signal selection switch and a signal output end;
the input ends of a first transmission line and a second transmission line of a transmission line transformer (2) of the differential mode noise detection circuit are respectively connected with a live line and a zero line, and the output ends of the first transmission line and the second transmission line are grounded through a first resistor (4); the output end of the first transmission line is also connected with a signal output end; the first transmission line and the second transmission line are both connected with a grounding capacitor (3);
the input ends of a first inductor (5) and a second inductor (6) of the common mode noise detection circuit are respectively connected with a zero line and a live line, and the output ends of the common mode noise detection circuit are both connected with a second resistor and are connected with a signal output end through the second resistor; the input ends of the first inductor (5) and the second inductor (6) are connected with each other through a second capacitor (7), and the output ends of the first inductor and the second inductor are connected with each other through a third capacitor (10);
the differential mode noise detection circuit and the common mode noise detection circuit are both connected with a selection switch (11); the selection switch (11) is connected with the signal output end.
2. The conducted noise detecting apparatus according to claim 1, wherein: the live wire and the zero wire are both connected with a first capacitor (1); the first capacitor (1) has filtering and coupling functions.
3. The conducted noise detecting apparatus according to claim 1, wherein: the circuit also comprises an output protection circuit; the output protection circuit comprises a third inductor (12) and a fourth capacitor (13); and one ends of the third inductor (12) and the fourth capacitor (13) are connected with the signal output end, and the other ends of the third inductor and the fourth capacitor are grounded.
4. The conducted noise detecting apparatus according to any one of claims 1 to 3, wherein: the first resistor and the second resistor are both precision resistors.
5. The conducted noise detecting apparatus according to claim 4, wherein: the signal output end is a signal output coaxial end (14).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201922447472.2U CN211453828U (en) | 2019-12-27 | 2019-12-27 | Conduction noise detection device |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201922447472.2U CN211453828U (en) | 2019-12-27 | 2019-12-27 | Conduction noise detection device |
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| CN211453828U true CN211453828U (en) | 2020-09-08 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112578191A (en) * | 2020-12-25 | 2021-03-30 | 中汽研汽车检验中心（天津）有限公司 | New energy vehicle and component electromagnetic compatibility performance test system |
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2019
- 2019-12-27 CN CN201922447472.2U patent/CN211453828U/en active Active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112578191A (en) * | 2020-12-25 | 2021-03-30 | 中汽研汽车检验中心（天津）有限公司 | New energy vehicle and component electromagnetic compatibility performance test system |
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