CN100403633C - High-attenuation ultra-small common mode conduction electromagnetic interference active filter - Google Patents
High-attenuation ultra-small common mode conduction electromagnetic interference active filter Download PDFInfo
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- CN100403633C CN100403633C CNB2006100427430A CN200610042743A CN100403633C CN 100403633 C CN100403633 C CN 100403633C CN B2006100427430 A CNB2006100427430 A CN B2006100427430A CN 200610042743 A CN200610042743 A CN 200610042743A CN 100403633 C CN100403633 C CN 100403633C
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Abstract
The present invention discloses a high-attenuation ultra-small common-mode conduction electromagnetic interference active filter which comprises an annular high-frequency current transformer wound with three windings, wherein the winding directions of the three windings are the same; two of the three windings are connected to the leading-in end of an AC power supply, and the other winding is connected to the input end of an operational amplifier in series by a resistor; an output end of the operational amplifier back feeds signals to a noise source device by two high-voltage capacitors and resistors. The electromagnetic interference active filter of the present invention has the characteristics of simple and reasonable structure, high noise attenuation ability, good low-frequency filtering characteristic, small external dimension, light weight, etc., and meets the requirements of suppressing conduction electromagnetic interference of power electronic equipment, such as a switching power supply, etc.
Description
Technical field
The invention belongs to the production and the application of Electromagnetic interference filter, relate to the active Electromagnetic interference filter of the high attenuation multiple of a kind of miniaturization.
Background technology
When current power electronic equipment was used widely and is developed rapidly, the electromagnetic interference (EMI) problem that is accompanied by it was also more and more serious.Particularly in recent years, power inverter is constantly advancing towards high frequency, technique direction efficient, high power density, and this is to the electromagnetic noise that how effectively to suppress switching device and produce great challenge especially.The passive electromagnetic interface filter that is made of passive components such as inductance, electric capacity of extensive use at present is bulky, and filter effect is not good enough, and designs and produces the process complexity, is easy to generate resonance.According to the data-searching that the applicant carried out, the at present product and the relevant report of the electromagnetic interface filter that does not also constitute by active elements such as operational amplifiers.
Summary of the invention
The objective of the invention is to, a kind of Electromagnetic interference filter based on active element is provided, traditional relatively passive electromagnetic interface filter, it is stronger that this filter has the noise attentuation ability, the advantage that overall dimension is littler, the Conducted Electromagnetic Interference that is specially adapted to power electronic equipments such as Switching Power Supply suppresses.
The technical solution that realizes above-mentioned purpose is: a kind of high-attenuation ultra-small common mode conduction electromagnetic interference active filter, it is characterized in that, this filter comprises annular HF current transformer, be wound with 3 windings respectively on the annular HF current transformer circumference, the coiling direction of 3 windings is homophase, the input of 2 windings wherein is connected to the AC power end of incoming cables, the output of these 2 windings is connected respectively to the input live wire and the zero line side of noise power-supply device, an end ground connection of noise power-supply device; One end ground connection of another winding, the other end is connected to an input of operational amplifier A by first resistance R 1, another input of operational amplifier A is by second resistance R, 2 ground connection, the output of operational amplifier A is connected to the input live wire end of noise power-supply device respectively through the first higfh-tension ceramics capacitor C 1, be connected to the zero line side of noise power-supply device through the second higfh-tension ceramics capacitor C 2, the first higfh-tension ceramics capacitor C 1 and the second higfh-tension ceramics capacitor C 2 are respectively through the 3rd resistance R 3 ground connection.
Active Electromagnetic interference filter of the present invention owing to adopted HF current transformer, has not only realized the accurate detection of HF noise signal but also has effectively rejected the fundamental frequency signal.Adopted high-speed wideband current mode operational amplifier simultaneously, greatly improved dynamic response and the frequency response ability of filter interference signal.Adopt higfh-tension ceramics electric capacity at output, overcome of the influence of grid side high pressure, realized the automatic feedback of noise signal simultaneously operational amplifier.This filter has that circuit structure is simple, design is convenient, volume is little, in light weight, the noise attentuation ability is strong, to characteristics such as the low frequency signal filter effect are especially obvious, the Conducted Electromagnetic Interference that is specially adapted to power electronic equipments such as Switching Power Supply suppresses.
Description of drawings
Fig. 1 is an electromagnetic interference active filter circuit structure schematic diagram of the present invention;
Fig. 2 is an electromagnetic interference active filter actual device structure photo of the present invention;
Fig. 3 is the experimental result of electromagnetic interference active filter of the present invention;
The embodiment that realizes below in conjunction with accompanying drawing and inventor and the present invention are used for the operation principle that the 300W computer switching power supply exchanges end of incoming cables common mode electromagnetic interference inhibition and are described in further detail.
Embodiment
See figures.1.and.2, common mode electromagnetic interference active filter of the present invention, comprise high frequency common mode electromagnetic interference current transformer, be wound with 3 windings on the circumference of instrument transformer, the coiling direction of 3 windings is homophase, and wherein 2 windings are connected in series to the interchange inlet wire of noise power-supply device, i.e. live wire and zero line respectively, another winding is connected to the input (negative terminal) of operational amplifier A by series resistance R1, and the input of operational amplifier A also has a resistance R 2 (anode).Operational amplifier A is operated in open loop situations, and its output is connected with 2 higfh-tension ceramics capacitor C 1 and C2 and a resistance R 3, and higfh-tension ceramics capacitor C 1 and C2 are connected respectively to output signal the live wire and the zero line side of noise power-supply device inlet wire.
The high frequency common mode current mutual inductor serial is in AC network, high frequency common mode disturbance current signal that can the detection noise source device.Because 3 windings all adopt the homophase coiling, so the common mode interference signal of the electrical network of only taking a sample does not then process for differential mode noise.The cut-off frequency of instrument transformer is determined by formula (1):
In the formula, n is the no-load voltage ratio of former secondary winding, μ
0Be permeability of vacuum, μ
rBe the magnetic permeability of core material, A
cBe the cross-sectional area of magnetic core, 1 is the effective length of magnetic core, and R is the equiva lent impedance of secondary.In order to improve the noise signal sampling precision of instrument transformer, should make cut-off frequency low as far as possible, to obtain the noise information in the more abundant more broad frequency range.
Operational amplifier is mainly realized the further amplification to detection signal.In order to obtain higher gain, operational amplifier is operated in open loop situations.Bandwidth of operational amplifiers is enough wide simultaneously, so that the noise signal in the detected frequency band of instrument transformer all can distortionlessly be amplified.According to the design standard of national electromagnetic compatibility, information electrical type equipment disturbed test frequency band range is 150kHz～30MHz, so bandwidth of operational amplifiers should be not less than 50MHz.
Amplify voltage signal afterwards through operational amplifier and refill electrical network by electric capacity at last.Because there is the 220V power frequency high voltage in the interchange end of incoming cables of equipment, therefore, feedback electric capacity must be selected high voltage bearing ceramic condenser.Simultaneously, excessive for fear of the leakage current between live wire and the zero line, the value of electric capacity also be difficult for to be selected excessive, generally just enough at the pF order of magnitude, two electric capacity that present embodiment adopts be 4700pF, the value withstand voltage is 2kV.
The photo of the active Electromagnetic interference filter that the inventor finishes by technique scheme as shown in Figure 2.Its overall dimensions: 43mm * 22mm, instrument transformer are ferrite material, diameter 18mm, the no-load voltage ratio of former secondary 1: 1, series resistance R1 is 10k Ω, balance resistance R2 is 10k Ω, the amplifier model is THS4001, and output capacitance is a high pressure magnetic sheet electric capacity, 4700pF/2kV.Test result as shown in Figure 3.Reached purpose of design through experiment showed.
Claims (4)
1. high-attenuation ultra-small common mode conduction electromagnetic interference active filter, it is characterized in that, this filter comprises annular HF current transformer, be wound with 3 windings respectively on the annular HF current transformer circumference, the coiling direction of 3 windings is homophase, the input of 2 windings wherein is connected to the AC power end of incoming cables, and the output of these 2 windings is connected respectively to the input live wire and the zero line side of noise power-supply device, an end ground connection of noise power-supply device; One end ground connection of another winding, the other end is connected to an input of operational amplifier (A) by first resistance (R1), another input of operational amplifier (A) is by second resistance (R2) ground connection, the output of operational amplifier (A) is connected to the input live wire end of noise power-supply device respectively through the first higfh-tension ceramics electric capacity (C1), be connected to the zero line side of noise power-supply device through the second higfh-tension ceramics electric capacity (C2), the first higfh-tension ceramics electric capacity (C1) and the second higfh-tension ceramics electric capacity (C2) are respectively through the 3rd resistance (R3) ground connection.
2. high-attenuation ultra-small common mode conduction electromagnetic interference active filter as claimed in claim 1, it is characterized in that, described operational amplifier (A) is operated in open loop situations, promptly between the input of operational amplifier (A) and the output without any electric connection.
3. high-attenuation ultra-small common mode conduction electromagnetic interference active filter as claimed in claim 1, it is characterized in that, described HF current transformer is arranged near AC power end of incoming cables one side, and the connected mode of HF current transformer and AC power is for being connected in series.
4. high-attenuation ultra-small common mode conduction electromagnetic interference active filter as claimed in claim 1 is characterized in that described bandwidth of operational amplifiers is not less than 50MHz.
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| CNB2006100427430A CN100403633C (en) | 2006-04-27 | 2006-04-27 | High-attenuation ultra-small common mode conduction electromagnetic interference active filter |
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| CNB2006100427430A CN100403633C (en) | 2006-04-27 | 2006-04-27 | High-attenuation ultra-small common mode conduction electromagnetic interference active filter |
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| CN100403633C true CN100403633C (en) | 2008-07-16 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2022016395A1 (en) * | 2020-07-21 | 2022-01-27 | AnApp Technologies Limited | Electromagnetic interference suppression circuit and related sensing circuit |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100427957C (en) * | 2006-11-28 | 2008-10-22 | 南京师范大学 | Device and method for measuring internal impedance of noise source of switch power supply EMI |
| CN101527505B (en) * | 2009-03-31 | 2012-05-23 | 西安交通大学 | Disturbance voltage attenuation device |
| US8649193B2 (en) * | 2010-04-05 | 2014-02-11 | Mitsubishi Electric Corporation | Leakage current reducing apparatus |
| CN102256194A (en) * | 2011-06-23 | 2011-11-23 | 胡国强 | Sound device with alternating current filter |
| JP6555180B2 (en) * | 2016-04-18 | 2019-08-07 | 株式会社豊田自動織機 | Motor drive device |
| US10374510B2 (en) * | 2017-04-07 | 2019-08-06 | Texas Instruments Incorporated | Compensated active electro-magnetic interference filters |
| CN107147280A (en) * | 2017-06-21 | 2017-09-08 | 山东超越数控电子有限公司 | A kind of support plate design method of improvement DC DC switch power supply EMIs |
| CN109617391B (en) * | 2018-12-25 | 2020-08-18 | 西安理工大学 | Stepless controllable suppression capability switching power supply EMI filter and design method thereof |
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| JP2001244770A (en) * | 2000-12-27 | 2001-09-07 | Mitsubishi Electric Corp | Noise filter |
| CN1370039A (en) * | 2001-02-14 | 2002-09-18 | 神达电脑股份有限公司 | Filter of electromagnetic interference |
| CN2709989Y (en) * | 2004-07-24 | 2005-07-13 | 刘新普 | 220V. AC. power-supply fastening signal isolator |
| CN1656665A (en) * | 2002-05-22 | 2005-08-17 | 国际整流器公司 | Active common mode emi filter |
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001244770A (en) * | 2000-12-27 | 2001-09-07 | Mitsubishi Electric Corp | Noise filter |
| CN1370039A (en) * | 2001-02-14 | 2002-09-18 | 神达电脑股份有限公司 | Filter of electromagnetic interference |
| CN1656665A (en) * | 2002-05-22 | 2005-08-17 | 国际整流器公司 | Active common mode emi filter |
| CN2709989Y (en) * | 2004-07-24 | 2005-07-13 | 刘新普 | 220V. AC. power-supply fastening signal isolator |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2022016395A1 (en) * | 2020-07-21 | 2022-01-27 | AnApp Technologies Limited | Electromagnetic interference suppression circuit and related sensing circuit |
| US11754611B2 (en) | 2020-07-21 | 2023-09-12 | AnApp Technologies Limited | Electromagnetic interference suppression circuit and related sensing circuit |
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| CN1866703A (en) | 2006-11-22 |
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