WO2019223803A1 - 差模电磁噪声提取网络及有源电磁干扰滤波器 - Google Patents

差模电磁噪声提取网络及有源电磁干扰滤波器 Download PDF

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Publication number
WO2019223803A1
WO2019223803A1 PCT/CN2019/088503 CN2019088503W WO2019223803A1 WO 2019223803 A1 WO2019223803 A1 WO 2019223803A1 CN 2019088503 W CN2019088503 W CN 2019088503W WO 2019223803 A1 WO2019223803 A1 WO 2019223803A1
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electromagnetic noise
mode electromagnetic
differential
differential mode
network
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PCT/CN2019/088503
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English (en)
French (fr)
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黄敏超
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敏业信息科技（上海）有限公司
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Publication of WO2019223803A1 publication Critical patent/WO2019223803A1/zh

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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/44—Circuits or arrangements for compensating for electromagnetic interference in converters or inverters
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H11/00—Networks using active elements
    • H03H11/02—Multiple-port networks
    • H03H11/04—Frequency selective two-port networks
    • H03H11/12—Frequency selective two-port networks using amplifiers with feedback

Definitions

  • the invention relates to the field of filtering technology, in particular to a differential mode electromagnetic noise extraction network and an active electromagnetic interference filter.
  • FIG. 1 is a schematic diagram of the connection between an electric device and a power supply system.
  • EMC European Union introduced electromagnetic compatibility
  • the power supply system may be an AC power supply system or a DC power supply system.
  • FIG. 2 is a schematic diagram of an application of a conventional passive EMI filter.
  • EMI electromagnetic interference
  • FIG. 2 in order to meet the electromagnetic interference (EMI) requirements in the EMC regulations, almost all electrical equipment will use passive EMI filters composed of passive components, connected in series to the electrical equipment and the power supply system. In order to suppress electromagnetic noise in electrical equipment, meet the requirements of EMI regulations limits, and avoid affecting the power supply system.
  • EMI electromagnetic interference
  • FIG. 3 is a schematic diagram of a conventional common-mode EMI filter.
  • the common-mode EMI filter consists of a common-mode inductor L cm and a capacitor C Y.
  • FIG. 4 is a schematic diagram of a conventional differential mode EMI filter.
  • the differential mode EMI filter is composed of a differential mode inductor L dm and a capacitor C X.
  • the losses are serious: when suppressing weak ⁇ A level electromagnetic noise, it is necessary to bear the load current of the electrical equipment at the same time, resulting in additional losses and heat generation, reducing the energy efficiency and reliability of the electrical equipment;
  • the volume is huge: in order to withstand the load current of the electrical equipment, the volume of the common mode inductor and the differential mode inductance will inevitably increase, and even exceed the volume of the functional circuit of the electrical equipment, which will become upside down;
  • near-field coupling Due to the large size of passive components and the influence of stray parameters, near-field coupling and resonance of electromagnetic noise occur in high frequency bands, causing the filtering effect to fall short of design expectations.
  • FIG. 5 is a conceptual diagram of a conventional active EMI filter. As shown in FIG. 5, in order to solve the defects of the conventional passive EMI filter, a conceptual structure of an active EMI filter is proposed.
  • the active EMI filter will collect the electromagnetic noise current or voltage signal generated by the subsequent-stage electrical equipment, and achieve closed-loop feedback after gain amplification to achieve the purpose of noise suppression.
  • the hybrid is amplified in the common-mode electromagnetic noise and injected into the common-mode loop, which finally results in a new common-mode electromagnetic noise caused by the mixed-mode electromagnetic noise, and thus does not achieve the expected common-mode electromagnetic noise suppression effect.
  • Some known active differential mode EMI filters obtain differential mode electromagnetic noise by sampling the inductor voltage signal connected in series on the DC bus, and after amplification processing, control the impedance of the MOSFET transistor to achieve the purpose of suppressing differential mode noise.
  • the DC bus of the power supply will include differential mode electromagnetic noise, as well as common mode electromagnetic noise. Therefore, the electromagnetic noise obtained from the inductor includes not only differential mode electromagnetic noise but also common mode electromagnetic noise. In this way, the differential-mode electromagnetic noise mixed with the common-mode electromagnetic noise is amplified and then injected into the differential-mode loop through the impedance change of the MOSFET transistor, which eventually causes new differential-mode electromagnetic noise caused by the common-mode electromagnetic noise, which eventually fails to reach the target. To the expected differential mode noise suppression effect.
  • Figure 6 is a test setup diagram of the existing standard conducted interference.
  • a standard test setup diagram for conducted interference according to CISP16-1-2 in which a standard linear impedance matching network (LISN) is used in series between the power supply grid system and the electrical equipment to extract the equipment under test Conducted noise.
  • the electromagnetic noise detected by the receiver is extracted through a linear impedance matching network (LISN) coupling.
  • the electromagnetic noise current I input 1 flowing on the input cable 11 includes 1/2 of the common mode electromagnetic noise current I CM and the differential mode electromagnetic noise current I DM in the same direction.
  • the electromagnetic noise current I input 2 flowing on the input cable 12 includes 1/2 common-mode electromagnetic noise current I CM in the same direction and reverse differential-mode electromagnetic noise current I DM in the same direction.
  • the 1/2 common-mode electromagnetic noise current I CM in the input cables 11 and 12 in the same direction will be returned to the receiver through the common-mode electromagnetic noise source 101 in the electrical equipment under test through the metal plate connected to the ground in the conduction test.
  • the common mode electromagnetic noise current I CM is detected by the receiver.
  • the differential mode electromagnetic noise source 100 in the electrical equipment under test generates a differential mode electromagnetic current flowing in the input cables 11 and 12 in the reverse direction. After being coupled by the LISN, it is detected by the receiver.
  • the schematic diagram of the conventional active EMI filter shown in FIG. 5 is suitable for suppressing both common mode electromagnetic noise and differential mode electromagnetic noise.
  • common-mode electromagnetic noise and differential-mode electromagnetic noise have different propagation paths. Differential mode electromagnetic noise can only propagate through differential mode circuits. Common-mode electromagnetic noise will only propagate through the common-mode path, but it will overlap on the input cable and inside the power equipment, and the other half of the propagation path of the common-mode electromagnetic noise is detected by the electromagnetic interference test receiver. . Therefore, it is critical to completely isolate and inject the differential common-mode noise in the electrical equipment to achieve the suppression of the differential common-mode electromagnetic noise.
  • the invention provides a differential mode electromagnetic noise extraction network and an active electromagnetic interference filter including the differential mode electromagnetic noise extraction network, which can use a small amount of differential mode electromagnetic noise of an electric device or even does not enter the power supply system.
  • An aspect of the present invention provides a differential-mode electromagnetic noise extraction network including an input cable, an electromagnetic noise sampling network, and a differential-mode electromagnetic noise extractor adapted to be connected between a power supply system and a power-consuming device; the electromagnetic noise sampling A network is provided between the input cable and the differential mode electromagnetic noise extractor, and is configured to sample the differential common mode electromagnetic noise of the input cable and output the sampled differential common mode electromagnetic noise to the input cable.
  • a differential mode electromagnetic noise extractor; the differential mode electromagnetic noise extractor is configured to extract and output differential mode electromagnetic noise among differential common mode electromagnetic noise sampled by the electromagnetic noise sampling network.
  • the input cable includes a first input cable and a second input cable connected in parallel;
  • the electromagnetic noise sampling network includes a first sampler and a second sampler; wherein the first sampler is disposed at On the first input cable, the first sampler is connected to the differential mode electromagnetic noise extractor; the second sampler is disposed on the second input cable, and the second sampler is connected to The differential mode electromagnetic noise extractor is connected.
  • the input cable includes a first input cable and a second input cable connected in parallel;
  • the electromagnetic noise sampling network includes an inductor, and the inductor includes two primary windings and two secondary sampling windings; wherein Two primary windings and two secondary sampling windings are coupled in a one-to-one correspondence; one of the primary windings is connected in series between the first input cable and the electrical equipment, and the other is The primary winding is connected in series between the second input cable and the electrical equipment; two first ends of the two secondary sampling windings are connected to ground, and two of the two secondary sampling windings are connected to ground. The second end is used to output the differential common mode electromagnetic noise corresponding to the input cable.
  • the input cable includes a first input cable and a second input cable connected in parallel;
  • the differential mode electromagnetic noise extractor includes a dual winding inductor; wherein the two windings have the same polarity, and The first ends of the two windings of the differential mode electromagnetic noise extractor are respectively used to receive differential common mode electromagnetic noise of the first input cable and the second input cable. The second end of each winding is used to output differential mode electromagnetic noise.
  • the input cable includes a first input cable and a second input cable connected in parallel;
  • the differential mode electromagnetic noise extractor includes a second operational amplifier, a fifth resistor, a sixth resistor, a seventh resistor, and a first Eight resistors; wherein the first end of the fifth resistor is used to receive the differential common mode electromagnetic noise of the first input cable, and the second end of the fifth resistor is connected to the negative input of the second operational amplifier.
  • the first terminal of the sixth resistor is connected to one end of the seventh resistor; the first terminal of the sixth resistor is used to receive the differential common mode electromagnetic noise of the second input cable; the second terminal of the sixth resistor is connected to the second operation; The positive input terminal of the amplifier is connected to one end of the eighth resistor; the seventh resistor is connected between the negative input terminal and the output terminal of the second operational amplifier; the eighth resistor is connected to the second operational amplifier. Between positive input and ground.
  • the differential mode electromagnetic noise extraction network samples the differential common mode electromagnetic noise of an input cable through an electromagnetic noise sampling network and outputs the sampled differential common mode electromagnetic noise to a differential mode electromagnetic noise extractor, which is equivalent to a differential mode
  • the electromagnetic noise extractor indirectly extracts differential mode electromagnetic noise from an input cable of an electric device.
  • the extracted differential mode electromagnetic noise is processed for gain and closed-loop feedback through an electromagnetic noise conversion network.
  • the processed differential mode electromagnetic noise is injected into the network through the differential mode electromagnetic noise, and is returned to the differential mode noise source in the electric equipment through the differential mode loop.
  • the differential mode electromagnetic noise of the electrical equipment can be small or even does not enter the power supply system, so that the surrounding environment and the power grid are not affected by the electromagnetic noise of the electrical equipment, and at the same time, the electrical equipment can meet the requirements of the EMI regulations .
  • Another aspect of the present invention also provides an active electromagnetic interference filter, which includes the differential mode electromagnetic noise extraction network as described above.
  • the active electromagnetic interference filter further includes an electromagnetic noise conversion network and a differential mode electromagnetic noise injection network; the electromagnetic noise conversion network is configured to perform gain and closed-loop feedback processing on the differential mode electromagnetic noise; The differential mode electromagnetic noise is returned to the electrical equipment through the differential mode electromagnetic noise injection network; the differential mode electromagnetic noise extraction network, the electromagnetic noise conversion network, and the differential mode electromagnetic noise injection network are sequentially connected.
  • FIG. 1 is a schematic diagram of a connection between an electric device and a power supply system
  • FIG. 2 is an application schematic diagram of an existing passive EMI filter
  • FIG. 3 is a schematic diagram of a conventional common-mode EMI filter
  • FIG. 4 is a schematic diagram of a conventional differential mode EMI filter
  • FIG. 5 is a conceptual diagram of a conventional active EMI filter
  • FIG. 6 is a test setup diagram of an existing standard conducted interference
  • FIG. 7 is a schematic diagram of a filtering technology of an active electromagnetic interference filter according to an embodiment of the present invention.
  • FIG. 8 is a first schematic diagram of an electromagnetic noise processing network according to an embodiment of the present invention.
  • FIG. 9 is a second schematic diagram of an electromagnetic noise processing network according to an embodiment of the present invention.
  • FIG. 10 is a first schematic diagram of an electromagnetic noise sampling network according to an embodiment of the present invention.
  • FIG. 11 is a second schematic diagram of an electromagnetic noise sampling network according to an embodiment of the present invention.
  • FIG. 12 is a first schematic diagram of an electromagnetic noise extraction network provided by an embodiment of the present invention.
  • FIG. 13 is a second schematic diagram of an electromagnetic noise extraction network provided by an embodiment of the present invention.
  • FIG. 14 is a schematic diagram of a differential mode electromagnetic noise injection network based on a semiconductor transistor according to an embodiment of the present invention.
  • 15 is a schematic diagram of a differential mode electromagnetic noise injection network based on a dual-winding differential mode inductor according to an embodiment of the present invention
  • 16 is a schematic diagram of a differential mode electromagnetic noise injection network based on a three-winding differential mode inductor according to an embodiment of the present invention
  • FIG. 17 is a schematic diagram of a capacitor-based common mode electromagnetic noise injection network according to an embodiment of the present invention.
  • FIG. 18 is a schematic diagram of a common mode electromagnetic noise injection network based on a ground capacitor according to an embodiment of the present invention.
  • 19 is a schematic diagram of a common mode electromagnetic noise injection network based on inductive electromagnetic according to an embodiment of the present invention.
  • FIG. 20 is a simplified circuit diagram of an AC input power adapter according to an embodiment of the present invention.
  • 21 is a simplified circuit diagram of a DC input switching power supply according to an embodiment of the present invention.
  • 22 is a simplified circuit diagram of an AC input power adapter according to an embodiment of the present invention.
  • FIG. 23 is a simplified circuit diagram of a DC input switching power supply according to an embodiment of the present invention.
  • 24 is a schematic diagram of an electromagnetic noise conversion network according to an embodiment of the present invention.
  • 25 is a schematic diagram of an active electromagnetic interference filter according to the first embodiment of the present invention.
  • FIG. 26 is a schematic diagram of an active electromagnetic interference filter according to a second embodiment of the present invention.
  • FIG. 27 is a schematic diagram of an active electromagnetic interference filter according to a third embodiment of the present invention.
  • FIG. 28 is a schematic diagram of an active electromagnetic interference filter according to a fourth embodiment of the present invention.
  • FIG. 29 is a schematic diagram of an active electromagnetic interference filter according to Embodiment 5 of the present invention.
  • 100-differential mode electromagnetic noise source 101-common mode electromagnetic noise source; 108-common mode electromagnetic noise component output terminal; 109-differential mode electromagnetic noise component output terminal; 11-first input cable; 12-second input line Cable; 111- electromagnetic noise of the first input cable; 121- electromagnetic noise of the second input cable; 21- electromagnetic noise processing network; 22- electromagnetic noise conversion network; 23- differential mode electromagnetic noise injection network; 25- total Mode electromagnetic noise injection network; 211-common mode electromagnetic noise extractor; 212-differential mode electromagnetic noise extractor; 213-electromagnetic noise sampler; 214-differential common mode electromagnetic noise extraction network; 215-first sampler; 216- Second sampler; 33-first operational amplifier; 34-second operational amplifier; 35-first resistance-capacitance network; 36-second resistance-capacitance network.
  • connection should be understood in a broad sense unless explicitly stated and limited otherwise.
  • they may be fixed connections or removable.
  • Connection, or integral connection it can be mechanical or electrical connection; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements.
  • connection, or integral connection it can be mechanical or electrical connection; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements.
  • FIG. 7 is a schematic diagram of an active EMI filtering technology according to an embodiment of the present invention.
  • an embodiment of the present invention proposes an active EMI filtering technology for separately suppressing differential common mode electromagnetic noise.
  • the electromagnetic interference filter implements this technique.
  • the active electromagnetic interference filter includes an electromagnetic noise processing network 21, an electromagnetic noise conversion network 22, a differential mode electromagnetic noise injection network 23, and a common mode electromagnetic noise injection network 25.
  • the active EMI filtering technology provided by the embodiment of the present invention extracts differential mode electromagnetic noise and common mode electromagnetic noise from input cables of electrical equipment through the electromagnetic noise processing network 21, and then inputs them to the electromagnetic noise conversion network 22 for gain. And closed-loop feedback processing, the processed differential mode electromagnetic noise and common mode electromagnetic noise are returned to the electrical equipment through the differential mode circuit in the differential mode electromagnetic noise injection network 23 and the common mode circuit in the common mode electromagnetic noise injection network 25, respectively. Sources of differential and common mode noise in. In this way, the internal circulation of electromagnetic noise can be realized, so that the electromagnetic noise of the electrical equipment does not even enter the power supply system, so that the surrounding environment and the power supply grid are not affected by the electromagnetic noise of the electrical equipment, and the electrical equipment can also meet the EMI. Requirements for regulatory limits.
  • the electromagnetic noise processing network 21 proposed in the embodiment of the present invention adopts an independent differential mode electromagnetic noise extraction network, and outputs it to the subsequent electromagnetic noise conversion network 22 for gain and closed-loop feedback processing.
  • the embodiment of the present invention proposes various forms of differential mode electromagnetic noise extraction networks to cooperate with the subsequent-stage electromagnetic noise conversion network 22 and the differential mode electromagnetic noise injection network 23.
  • the differential mode electromagnetic noise processing network provided by the embodiment of the present invention can achieve an isolation degree of greater than 60 dB from the common mode electromagnetic noise, which is equivalent to less than 0.1% of the extracted common mode electromagnetic noise from the common mode electromagnetic noise. Expected suppression effect.
  • the electromagnetic noise processing network 21 proposed in the embodiment of the present invention adopts an independent common-mode electromagnetic noise extraction network, and outputs it to the subsequent electromagnetic noise conversion network 22 for gain and closed-loop feedback processing.
  • the embodiments of the present invention propose various forms of common-mode electromagnetic noise extraction networks to cooperate with the subsequent-stage electromagnetic noise conversion network 22 and the common-mode electromagnetic noise injection network 25.
  • the common-mode electromagnetic noise extraction network provided by the embodiment of the present invention can achieve an isolation degree of greater than 60 dB from differential-mode electromagnetic noise, which is equivalent to less than 0.1% of the extracted common-mode electromagnetic noise. To achieve the desired suppression effect.
  • the active EMI filter proposed in the embodiment of the present invention uses an independent differential mode noise injection network 23 to inject the processed differential mode electromagnetic noise into the differential mode circuit of the electrical equipment, and by changing the differential mode in the differential mode circuit Impedance to suppress differential mode electromagnetic noise.
  • the embodiment of the present invention proposes multiple forms of differential mode electromagnetic noise injection network 23, which injects the differential mode electromagnetic noise after the pre-processing into the differential mode circuit of the electrical equipment, and realizes this by changing the differential mode impedance in the differential mode circuit. Suppression of electromagnetic noise.
  • the active EMI filter proposed in the embodiment of the present invention uses an independent common-mode noise injection network 25 to inject the processed common-mode electromagnetic noise into the common-mode loop of the electric equipment and then return to the common-mode circuit in the electric equipment.
  • Mode noise source forming an internal loop.
  • the embodiment of the present invention proposes various forms of common-mode electromagnetic noise injection network 25, injects the common-mode electromagnetic noise after the pre-processing into the common-mode loop of the electric equipment, and then returns to the common-mode noise source in the electric equipment.
  • An internal cycle is formed to suppress electromagnetic noise.
  • the active EMI filter provided by the embodiment of the present invention has the flexibility of the differential mode electromagnetic noise injection point, and can inject the differential mode electromagnetic noise at any point from the input cable to the differential mode circuit in the subsequent-stage electrical equipment. , By changing the differential mode impedance in the differential mode circuit, the suppression effect of electromagnetic noise is realized.
  • the active EMI filter provided by the embodiment of the present invention has the flexibility of a common-mode electromagnetic noise injection point, and the common-mode electromagnetic injection can be performed at any point from the input cable to the common-mode circuit in the subsequent-stage electrical equipment. Noise, and then return to the common mode electromagnetic noise source in the electrical equipment, forming an internal cycle to achieve the suppression of electromagnetic noise.
  • electromagnetic noise processing network 21, differential mode electromagnetic noise injection network 23, common mode electromagnetic noise injection network 25, and flexible electromagnetic noise injection points according to the embodiments of the present invention are described one by one.
  • the electromagnetic noise processing network 21 used in the active EMI filter provided by the embodiment of the present invention includes an electromagnetic noise extraction network.
  • the electromagnetic noise extraction network has the following two main implementation modes: a direct extraction network and an indirect extraction network, or correspondingly called Single-stage extraction network and two-stage extraction network are used to extract differential mode electromagnetic noise and common mode electromagnetic noise.
  • the electromagnetic noise extraction network includes a common-mode electromagnetic noise extractor and a differential-mode electromagnetic noise extractor.
  • the common-mode electromagnetic noise extractor is used to extract and output the common-mode electromagnetic noise of the input cable.
  • a common-mode electromagnetic noise extractor is used to directly extract and output common-mode electromagnetic noise of an input cable;
  • a differential-mode electromagnetic noise extractor is used to directly extract and output differential-mode electromagnetic noise of an input cable.
  • the common mode electromagnetic noise extractor is used to indirectly extract and output the common mode electromagnetic noise of the input cable;
  • the differential mode electromagnetic noise extractor is used to indirectly extract and output the differential mode electromagnetic noise of the input cable.
  • FIG. 8 is a schematic diagram when the electromagnetic noise processing network provided by the embodiment of the present invention is a unipolar extraction network.
  • the single-stage extraction network includes a common mode electromagnetic noise extractor 211 and a differential mode electromagnetic noise extractor 212.
  • the common mode electromagnetic noise extractor 211 and the differential mode electromagnetic noise extractor 212 are both current transformers.
  • the first input cable 11 passes through the inner ring of the common mode electromagnetic noise extractor 211 and the differential mode electromagnetic noise extractor 212 in order, and is then connected to the power consumption device; the second input cable 12 passes through the common mode electromagnetic noise extractor 211 After the inner ring of the ring, surround the ring body of the differential mode electromagnetic noise extractor 212 around the ring body in the thickness direction of the differential mode electromagnetic noise extractor 212, and then loop out, and then connect it to the electric equipment.
  • the common-mode electromagnetic noise current I CM output by the common-mode electromagnetic noise extractor 211 and the differential-mode electromagnetic noise current I DM output by the differential-mode electromagnetic noise extractor 212 are output to the next-stage electromagnetic noise conversion network 22 to perform gain and Closed-loop feedback processing.
  • FIG. 9 is a schematic diagram when the electromagnetic noise processing network provided by the embodiment of the present invention is a two-stage extraction network.
  • the two-stage extraction network includes an electromagnetic noise sampling network 213 and a differential common-mode electromagnetic noise extraction network 214.
  • the electromagnetic noise sampling network 213 is disposed between the input cable and the differential common-mode electromagnetic noise extraction network 214.
  • the electromagnetic noise sampling network 213 is configured to sample the differential common mode electromagnetic noise of the input cable and output the sampled differential common mode electromagnetic noise to the differential common mode electromagnetic noise extraction network 214.
  • the differential common-mode electromagnetic noise extraction network 214 is equivalent to the unipolar extraction network in the embodiment shown in FIG. 8, and includes a common-mode electromagnetic noise extractor 211 and a differential-mode electromagnetic noise extractor 212.
  • the common mode electromagnetic noise extractor 211 is used to extract and output the common mode electromagnetic noise of the differential common mode electromagnetic noise sampled by the electromagnetic noise sampling network 213, such as the common mode electromagnetic noise component shown in FIG. 9; the differential mode electromagnetic noise extraction The generator 212 is configured to extract and output differential mode electromagnetic noise, such as the differential mode electromagnetic noise component shown in FIG. 9, from the differential common mode electromagnetic noise sampled by the electromagnetic noise sampling network 213.
  • the electromagnetic noise sampling network 213 extracts the overall electromagnetic noise on each input cable, and then inputs it to the differential common mode electromagnetic noise extraction network 214.
  • the differential common-mode electromagnetic noise extraction network 214 separates the common-mode electromagnetic noise and the differential-mode electromagnetic noise, and then outputs them to the lower-level electromagnetic noise conversion network 22 for gain and closed-loop feedback processing.
  • the total electromagnetic noise on each input cable includes differential mode electromagnetic noise and common mode electromagnetic noise.
  • the electromagnetic noise sampling network 213 can sample the overall electromagnetic noise in each input cable in a variety of ways.
  • the multiple implementations of the electromagnetic noise sampling network 213 can be arbitrarily combined with the multiple implementations of the post-differential common-mode electromagnetic noise extraction network 214 according to the actual application needs to obtain more pure differential-mode electromagnetic noise and common-mode electromagnetic noise.
  • the electromagnetic noise sampling network 213 may adopt two implementation manners.
  • FIG. 10 is a schematic diagram of a first implementation manner of an electromagnetic noise sampling network according to an embodiment of the present invention.
  • the electromagnetic noise sampling network 213 includes a first sampler 215 and a second sampler 216.
  • the first sampler 215 is disposed on the first input cable 11, and the first sampler 215 is connected to the common mode electromagnetic noise extractor 211 or the differential mode electromagnetic noise extractor 212.
  • the second sampler 216 is disposed on the second input line. On the cable 12, the second sampler 216 is connected to the common mode electromagnetic noise extractor 211 or the differential mode electromagnetic noise extractor 212.
  • both the first sampler 215 and the second sampler 216 may be current transformers.
  • the current transformer samples the electromagnetic noise current on the input cable added to it, and the electromagnetic noise obtained in this way includes common mode electromagnetic noise and differential mode electromagnetic noise in the input cable.
  • FIG. 11 is a schematic diagram of a second implementation manner of an electromagnetic noise sampling network according to an embodiment of the present invention.
  • the electromagnetic noise sampling network 213 includes an inductor L 1 , and the inductor L 1 includes two primary windings N P1 and N P2 and two secondary sampling windings N S1 and N S2.
  • one primary winding N P1 is connected in series between the first input cable 11 and the electrical equipment, and the other primary winding N P2 is connected in series between the second input cable 12 and the electrical equipment;
  • two The secondary sampling windings N S1 and N S2 are coupled to the two primary windings N P1 and N P2 in a one-to-one correspondence, and the two second ends of the two secondary sampling windings N S1 and N S2 are used to output corresponding input cables.
  • common-mode electromagnetic noise are common-mode electromagnetic noise.
  • the electromagnetic noise sampling network 213 uses an inductor and a coupled winding to obtain the electromagnetic noise on each input cable.
  • the inductor L 1 is composed of 4 windings, which are the primary windings N P1 and N P2 , and the secondary side.
  • the sampling windings N S1 and N S2 , the primary winding N P1 and the secondary sampling winding N S1 adopt a tightly coupled winding method to achieve a high degree of coupling; the primary winding N P2 and the secondary sampling winding N S2 use a tightly coupled winding. Line mode to achieve high coupling.
  • the primary winding N P1 is connected in series between the first input cable 11 and the input of the electrical equipment, and the primary winding N P2 is connected in series between the second input cable 12 and the input of the electrical equipment. After one end of the secondary-side sampling windings N S1 and N S2 is grounded, the other end outputs electromagnetic noise coupled to the corresponding input cable.
  • the electromagnetic noise obtained in this way includes common mode electromagnetic noise and differential mode electromagnetic noise in the cable.
  • the implementation of the differential common-mode electromagnetic noise extraction network 214 is as follows:
  • the differential common-mode electromagnetic noise extraction network 214 can be isolated in various forms to obtain more pure differential-mode electromagnetic noise and common-mode electromagnetic noise as the input of the subsequent-stage electromagnetic noise conversion network 22.
  • the multiple implementations of the differential common-mode electromagnetic noise extraction network 214 can refer to the multiple implementations of the previous-stage electromagnetic noise sampling network 213. According to the actual application needs, any combination can be obtained to obtain more pure differential-mode electromagnetic noise and common-mode electromagnetic Noise is used as an input to the subsequent-stage electromagnetic noise conversion network 22.
  • differential common-mode electromagnetic noise extraction network 214 There are two implementations of the differential common-mode electromagnetic noise extraction network 214: a winding induced voltage cancellation method and an operational amplifier algebra and method.
  • FIG. 12 is a first schematic diagram of an electromagnetic noise extraction network provided by an embodiment of the present invention.
  • the differential common mode electromagnetic noise extraction network 214 can be implemented by a winding induced voltage cancellation method of a magnetic device to obtain more pure differential mode electromagnetic noise and common mode electromagnetic noise.
  • the common mode electromagnetic noise extractor and the differential mode electromagnetic noise extractor are dual-winding inductors, which are L 1 and L 2 respectively .
  • the two windings of the dual-winding inductor L 1 used by the common-mode electromagnetic noise extractor have opposite polarities, and the first ends of the two windings of the common-mode electromagnetic noise extractor are respectively used to receive the first input cable 11 and the first winding.
  • L two pairs of differential mode inductance coil uses electromagnetic noise extraction 2
  • the windings have the same polarity.
  • the first ends of the two windings of the differential mode electromagnetic noise extractor are used to receive the differential common mode electromagnetic noise of the first input cable 11 and the second input cable 12, respectively.
  • the second ends of the two windings of the dual-winding inductor L 1 and the dual-winding inductor L 2 used by the converter are both used to output differential mode electromagnetic noise.
  • the two ends of the two windings of the dual-winding inductor L 1 with opposite polarities are respectively connected to the electromagnetic noise 111 of the first input cable 11 and the electromagnetic noise 121 of the second input cable 12 output from the previous-stage electromagnetic noise sampling network 213. ;
  • the other ends of the two windings of the dual-winding inductor L 1 are connected as a common-mode electromagnetic noise output after being connected.
  • the differential mode currents in the first input cable 11 and the second input cable 12 are in the same direction, and the differential mode currents in the first input cable 11 and the second input cable 12 are opposite to each other, so According to the magnetic principle, the induced voltages generated by the common-mode current of the first input cable 11 and the second input cable 12 in the windings of the magnetic core in the dual-winding inductor L 1 cancel each other, in other words, the common-mode current There is no inhibiting effect, on the contrary it has inhibiting effect on the differential mode current. Therefore, the differential mode electromagnetic noise can be isolated through a connection method such as the double-winding inductor L 1 to obtain pure common mode electromagnetic noise.
  • common mode electromagnetic noise can also be isolated.
  • the two ends of the two windings of the dual-winding inductor L 2 having the same polarity are respectively connected to the electromagnetic noise 111 of the first input cable 11 and the electromagnetic noise 121 of the second input cable 12 output from the previous-stage electromagnetic noise sampling network 3213.
  • the other ends of the two windings of the dual-winding inductor L 2 are connected as a differential mode electromagnetic noise output after being connected.
  • the differential mode currents in the first input cable 11 and the second input cable 12 are opposite to each other, and the common mode currents in the first input cable 11 and the second input cable 12 are the same. Therefore, according to the magnetic principle, the induced voltages generated by the same-mode differential currents of the first input cable 11 and the second input cable 12 in the windings of the magnetic core in the dual-winding inductor L 2 cancel each other. In other words, the differential mode The current has no inhibitory effect, and conversely it has a suppressive effect on the common mode current. Therefore, the common mode electromagnetic noise can be isolated through a connection method such as the double-winding inductor L 2 to obtain pure differential mode electromagnetic noise.
  • FIG. 13 is a second schematic diagram of an electromagnetic noise extraction network provided by an embodiment of the present invention.
  • the differential common-mode electromagnetic noise extraction network 214 can also be implemented by a logarithmic sum of operational amplifiers to obtain more pure differential-mode electromagnetic noise and common-mode electromagnetic noise.
  • the other end of the first resistor R 1 is connected to the electromagnetic noise 111 of the first input cable 11; a second resistor R The other end of 2 is connected to the electromagnetic noise 121 of the second input cable 12.
  • the input cable of the first electromagnetic noise current I input 11 of the cable 1 and the second input 12 of the electromagnetic noise current I input algebraically adding 2 I 1 + I input Input 2 to get the common mode electromagnetic noise I CM in this way and isolate the differential mode electromagnetic noise I DM .
  • subtraction can also be implemented to obtain differential-mode electromagnetic noise, while isolating common-mode electromagnetic noise.
  • Differential output mode by the second electromagnetic noise operational amplifier 34 a fifth resistor R 5, the sixth resistor R 6, R 7 seventh resistor and an eighth resistor R 8 to achieve the objectives of common mode electromagnetic noise isolation.
  • the negative input terminal of the second operational amplifier 34 is connected to the fifth resistor R 5 and the seventh R 7 ; the positive input terminal of the second operational amplifier 34 is connected to the sixth resistor R 6 and the eighth resistor R 8 .
  • the output of the second operational amplifier 34 is connected to the seventh resistor R 7 and at the same time serves as the differential mode electromagnetic noise component output 109; the other end of the fifth resistor R 5 is connected to the electromagnetic noise of the first input cable 11 111 is connected; the other end of the fifth resistor R 6 is connected to the electromagnetic noise 121 of the second input cable 12.
  • the connector may be implemented algebraically embodiment of the operational amplifier and resistor network, the first input 11 of the cable electromagnetic noise current I input and a second input 12 of the cable electromagnetic noise current I input 2 input I 1 -I algebraically Enter 2 to get the differential mode electromagnetic noise I DM and isolate the common mode electromagnetic noise I CM .
  • the implementation method of the "algebraic sum of operational amplifiers" described above is one of the implementation methods of realizing algebraic addition and subtraction of common mode electromagnetic noise and differential mode electromagnetic noise in an input cable.
  • + Vcc and -Vcc referred to in the drawings of this embodiment represent a positive power source and a negative power source, respectively.
  • the differential mode electromagnetic noise injection network 23 can be implemented in a variety of ways, including: in the form of a semiconductor transistor and a differential mode inductor.
  • FIG. 14 is a schematic diagram of a differential mode electromagnetic noise injection network based on a semiconductor transistor according to an embodiment of the present invention.
  • the semiconductor transistor in the differential mode electromagnetic noise injection network 23 based on a semiconductor transistor, the semiconductor transistor is a field effect transistor Q 1 whose drain is connected to the first input cable 11 and whose source is connected to an electrical device. Its gate is connected to the differential-mode electromagnetic noise component output terminal 109 of the preceding-stage electromagnetic noise conversion network 22.
  • Active EMI filter according to embodiments of the present invention can be made by using the gate voltage of the transistor Q 1 'changes by adjusting the first input differential-mode impedance on the cable 11, in order to achieve the purpose of suppressing electromagnetic noise in differential mode.
  • the field effect transistor Q 1 can be placed at any position in the differential mode circuit, which can suppress the differential mode electromagnetic noise. purpose. For example, it is placed on the second input cable 12 or in the differential mode circuit of the subsequent-stage electrical equipment.
  • FIG. 15 is a schematic diagram of a differential mode electromagnetic noise injection network based on a dual-winding differential mode inductor according to an embodiment of the present invention.
  • the differential-mode inductance L 3 has two windings: a primary winding N P and a secondary winding N S ; and a dual-winding differential mode inductor.
  • One end of the primary winding N P of L 3 is connected to the differential mode electromagnetic noise component output terminal 109 of the previous-stage electromagnetic noise conversion network 22, and the other end is grounded; one end of the secondary winding N S of the dual-winding differential mode inductor L 3 is connected to the first One input cable 11 and the other end are connected to the subsequent-stage electrical equipment.
  • Active EMI filter according to embodiments of the present invention can be made using a dual winding differential mode inductance L of the primary winding N P 3 of the preceding stage differential mode components of electromagnetic noise is coupled to the switching network 22 L double secondary winding 3 of the differential mode inductance In the differential mode circuit where the winding N S is located, the differential mode impedance of the differential mode circuit is changed, thereby achieving the purpose of suppressing the differential mode noise.
  • FIG. 16 is a schematic diagram of a differential mode electromagnetic noise injection network based on a three-winding differential mode inductor according to an embodiment of the present invention.
  • the three-window differential mode inductor L 4 has three windings: a primary winding N P1 , a first secondary winding N S1, and a second winding.
  • the secondary winding N S2 one end of the primary winding N P1 of the three-winding differential mode inductor L 4 is connected to the differential mode electromagnetic noise component output terminal 109 of the preceding-stage electromagnetic noise conversion network 22, and the other end is grounded; the three-winding differential mode inductor L 4 of the first secondary winding N S1 first input end of a cable 11, the other end of the electricity device; three-winding differential mode inductance L 4 of the second secondary winding N S2 second input line connected at one end Cable 12, the other end is connected to the post-stage electrical equipment.
  • the active electromagnetic interference filter proposed in the embodiment of the present invention can use the primary winding N P1 of the three-winding differential mode inductor L 4 to couple the differential-mode electromagnetic noise component output terminal 109 of the previous-stage electromagnetic noise conversion network 22 to the three-winding differential mode.
  • the differential mode impedance of the differential mode circuit is changed, thereby achieving the purpose of suppressing differential mode noise.
  • the following is an implementation manner of the common mode noise injection network 25.
  • the common mode noise injection network 25 can also be implemented in a variety of ways, including: a capacitor-based common mode noise injection network 25, a grounded capacitor-based common mode noise injection network 25, and a common mode inductance based common mode noise injection network 25.
  • FIG. 17 is a schematic diagram of a capacitor-based common mode electromagnetic noise injection network according to an embodiment of the present invention.
  • the first capacitance C 1, C 2, and a second capacitor end of the third capacitor C 3 connected together; the other terminal of the first capacitor C 1 and The first input cable 11 is connected to the subsequent-stage electrical equipment, and the other end of the second capacitor C 2 is connected to the second input cable 12 and the subsequent-stage electrical equipment; the other end of the third capacitor C 3 is connected to the previous-stage electromagnetic noise
  • the common-mode electromagnetic noise component output terminal 108 of the conversion network 22 is connected.
  • the active EMI filter proposed in the embodiment of the present invention can inject the common-mode electromagnetic noise component output terminal 108 of the previous-stage electromagnetic noise conversion network 22 to the common capacitor through the first capacitor C 1 , the second capacitor C 2, and the third capacitor C 3.
  • the common-mode current is returned to the subsequent-stage electrical equipment, and the purpose of suppressing the common-mode electromagnetic noise is achieved, and at the same time, the EMI receiver can detect a small amount, or even the common-mode noise.
  • connection method of the capacitor-based common-mode noise injection network 25 does not need to involve earth, so it can be applied not only to Class I electrical equipment with input ground, but also to Class II electrical equipment without input to ground, and DC power supply. Power equipment.
  • FIG. 18 is a schematic diagram of a common mode electromagnetic noise injection network based on a ground capacitor according to an embodiment of the present invention.
  • the common mode noise injection network 25 based on the ground capacitor, one end of the fourth capacitor C 4 is connected to the common mode electromagnetic noise component output terminal 108 of the previous-stage electromagnetic noise conversion network 22, and the other end is connected to the ground or The enclosure of an electric device.
  • the active EMI filter proposed in the embodiment of the present invention can inject the common mode output component of the previous-stage electromagnetic noise conversion network 22 into the common mode noise loop through the fourth capacitor C 4 , so that the common mode electromagnetic noise returns to the common mode noise source as soon as possible. , Can be small or even not detected by the EMI receiver common mode noise.
  • FIG. 19 is a schematic diagram of a common mode electromagnetic noise injection network based on common mode electromagnetic according to an embodiment of the present invention.
  • the common mode inductor L 5 has three windings: a primary winding N P1 , a first secondary winding N S1, and a second secondary winding N S2. .
  • One end of the primary winding N P1 of the common mode inductor L 5 is connected to the common mode electromagnetic noise component output terminal 108 of the previous-stage electromagnetic noise conversion network 22, and the other end is grounded; one end of the first secondary winding N S1 of the common mode inductor L 5 is connected To the first input cable 11, the other end is connected to the power consumption equipment; one end of the second secondary winding N S2 of the common mode inductor L 5 is connected to the second input cable 12, and the other end is connected to the power consumption equipment.
  • Active EMI filter according to the embodiment of the present invention can be made by the primary winding L N P 1 before the common mode component of the output stage switching network 22 of an electromagnetic noise of the inductor 5, the inductance L of the secondary winding N 5 and N Sl S2 is injected into the common mode noise loop to cancel the common mode current in the common mode loop, which can reduce the common mode noise detected by the EMI receiver.
  • the injection point of the differential mode electromagnetic noise injection network 23 proposed in the embodiment of the present invention may be any position in the differential mode loop, and the suppression effect of the differential mode electromagnetic noise can be achieved.
  • the differential mode circuit mentioned in the embodiments of the present invention refers to the components, circuits, and input cables inside the electrical equipment through which the differential mode current I DM flows.
  • FIG. 20 is a simplified circuit diagram of an AC input power adapter according to an embodiment of the present invention.
  • the loop indicated by the black arrow is a differential mode loop through which the differential mode current I DM flows, from the hot line L, the rectifier bridge BD1, the capacitor C 1 to the neutral line N, and also includes the connection between the devices.
  • the injection point of differential mode electromagnetic noise can be selected from the four points indicated by A, B, C, and D in the circuit shown in FIG. 20, where point A is the live line L and point B is the rectifier bridge.
  • two points A / D can be considered as the insertion points of the two secondary windings of the three-winding differential mode inductor, or B / C Two points are used as the insertion points of the two secondary windings of the three-winding differential mode inductor.
  • FIG. 21 is a simplified circuit diagram of a DC input switching power supply according to an embodiment of the present invention.
  • the loop indicated by the black arrow is a differential mode loop through which the differential mode current I DM flows.
  • the differential mode circuit is connected from the positive input terminal, and the capacitor C 1 is connected to the negative input terminal.
  • the injection point of the differential mode electromagnetic noise proposed in the embodiment of the present invention can be selected from points A and B for injection in FIG. 21. Point A is the line connecting the positive input, and point B is the line connecting the negative input.
  • two points A / B can be considered as the insertion points of the two secondary windings of the three-winding differential mode inductor.
  • the injection point of the common-mode electromagnetic noise injection network 25 can be at any position in the common-mode loop, and the suppression effect of the common-mode electromagnetic noise can be achieved.
  • the common mode circuit mentioned in the present invention refers to the devices, circuits, input cables and ground inside the electric equipment through which the common mode current I CM flows.
  • FIG. 22 is a simplified circuit diagram of an AC input power adapter according to an embodiment of the present invention.
  • a black arrow indicates a common mode loop through which a common mode current I CM flows.
  • Common mode loop from the firing line L, neutral line N, bridge rectifier BD1 positive connection of the capacitor C 1, the bridge rectifier BD1 and a negative electrode connecting capacitor C 1, the drain of the transistor Q 1 ', and the drain of the parasitic capacitance of the earth C sent into the earth; another common mode loop from the transformer connected to the anode of the rectifier diode and the parasitic capacitance C of the earth to send, into the earth.
  • the injection points of the common-mode electromagnetic noise injection network 25 can be selected from points A, B, C, and D. Unlike the differential-mode electromagnetic noise injection network 23, a single point can be selected for injection. The common-mode electromagnetic noise injection network 25 can be selected. The injection point must be selected for paired injection. When the capacitor-based common-mode electromagnetic noise injection network 25 shown in FIG. 17 is used, points A and B must be selected as the connection points of the capacitor C 1 and the capacitor C 2 at the same time. Similarly, when a common-mode electromagnetic noise injection network 25 using a three-winding common-mode inductor is used, the secondary windings of the common-mode inductor must be inserted at points A and B at the same time.
  • FIG. 23 is a simplified circuit diagram of a DC input switching power supply according to an embodiment of the present invention.
  • a loop indicated by a black arrow is a common mode loop through which a common mode current I CM flows.
  • the common mode circuit is from the connection between the input positive electrode and the capacitor C 1 , the connection between the input negative electrode and the capacitor C 1 , the connection between the capacitor C 1 and the drain of the transistor Q 1 , and the connection between the capacitor C 1 and the source of the transistor Q 2 .
  • the injection points of the common-mode electromagnetic noise injection network 25 can be selected from points A, B, C, and D. Unlike the differential-mode electromagnetic noise injection network 23, a single point can be selected for injection.
  • the common-mode electromagnetic noise injection network 25 can be selected. The injection point must be selected for paired injection. When a capacitor-based common-mode electromagnetic noise injection network 25 is used, point A and point B must be selected as the connection points of capacitor C 1 and capacitor C 2 at the same time. Similarly, when a common-mode electromagnetic noise injection network 25 based on a three-winding common-mode inductor is used, the secondary windings of the common-mode inductor must be inserted at points A and B at the same time.
  • FIG. 24 is a schematic diagram of an electromagnetic noise conversion network according to an embodiment of the present invention.
  • the main function of the electromagnetic noise conversion network 22 according to the embodiment of the present invention is to amplify and close-loop feedback processing the differential mode electromagnetic noise and common mode electromagnetic noise output by the previous-stage electromagnetic noise processing network 21. It is then output to the differential-mode electromagnetic noise injection network 23 and the common-mode electromagnetic noise injection network 25 at the subsequent stage.
  • the electromagnetic noise conversion network 22 may use an operational amplifier, a first resistance-capacitance network 35 and a second resistance-capacitance network 36 to implement gain amplification and closed-loop feedback.
  • the electromagnetic noise conversion network 22 may perform gain adjustment and phase adjustment by adjusting resistance and capacitance values in the first resistance-capacitance network 35 and the second resistance-capacitance network 36 to achieve the gain and phase required to suppress electromagnetic noise.
  • the active EMI filtering technology provided by the embodiment of the present invention is not only applicable to an AC power supply system, but also applicable to a DC power supply system.
  • the active EMI filtering technology provided by the embodiment of the present invention is applicable to Class I electrical equipment with a ground wire input, and also applicable to Class II electrical equipment without a ground wire input.
  • FIG. 25 is a schematic diagram of an active electromagnetic interference filter according to the first embodiment of the present invention.
  • a first embodiment of the present invention proposes an active electromagnetic interference filter.
  • the first embodiment extracts electromagnetic noise generated by an electrical equipment through an electromagnetic noise processing network 21 to obtain differential mode electromagnetic noise and common mode electromagnetic noise, respectively.
  • the differential mode electromagnetic noise injection network 23 passes the processed differential mode electromagnetic noise through the differential mode loop to offset the subsequent stage electrical equipment in the differential mode loop.
  • the generated differential mode noise, and at the same time, the processed common mode electromagnetic noise is returned to the common mode noise source in the electric equipment through the common mode loop through the common mode electromagnetic noise injection network 25, thereby realizing the internal circulation mode of electromagnetic noise and satisfying electromagnetic interference.
  • the requirements of (EMI) regulatory limits make the power supply system and the surrounding environment unaffected by electromagnetic noise generated by electrical equipment.
  • the electromagnetic noise processing network 21 in Embodiment 1 of the present invention is composed of two current transformers, and respectively obtains a differential mode current I DM generated by differential mode electromagnetic noise and a common mode current I CM generated by common mode electromagnetic noise.
  • the differential mode electromagnetic noise injection network 23 in the first embodiment of the present invention adopts a semiconductor mode-based differential mode electromagnetic noise injection network; the common mode electromagnetic noise injection network 25 in the first embodiment of the present invention uses a capacitor-based common mode electromagnetic noise injection network. .
  • FIG. 26 is a schematic diagram of an active electromagnetic interference filter according to a second embodiment of the present invention.
  • a second embodiment of the present invention proposes an active electromagnetic interference filter.
  • the electromagnetic noise generated by the electrical equipment is extracted through the electromagnetic noise processing network 21 to obtain a differential mode electromagnetic noise and a common mode electromagnetic noise, respectively.
  • the differential mode electromagnetic noise injection network 23 passes the processed differential mode electromagnetic noise through the differential mode loop to offset the difference generated by the subsequent stage electrical equipment in the differential mode loop.
  • the common mode electromagnetic noise injection network 25 is used to return the processed common mode electromagnetic noise to the common mode noise source in the electrical equipment through the common mode loop, thereby realizing the internal circulation of electromagnetic noise to meet electromagnetic interference (EMI)
  • EMI electromagnetic interference
  • the electromagnetic noise processing network 21 in the second embodiment of the present invention is composed of an electromagnetic noise sampling network 213 and a differential common-mode electromagnetic noise extraction network 214.
  • the electromagnetic noise sampling network 213 performs sampling through a current transformer.
  • the differential common-mode electromagnetic noise extraction network 214 uses a magnetic cancellation method to extract differential-mode electromagnetic noise and common-mode electromagnetic noise.
  • the differential mode electromagnetic noise injection network 23 in the second embodiment of the present invention uses a semiconductor transistor-based differential mode electromagnetic noise injection network; the common mode electromagnetic noise injection network 25 in the second embodiment of the present invention uses a capacitor-based common mode electromagnetic noise injection network. .
  • FIG. 27 is a schematic diagram of an active electromagnetic interference filter according to a third embodiment of the present invention.
  • an active electromagnetic interference filter according to the third embodiment of the present invention extracts electromagnetic noise generated by electrical equipment through an electromagnetic noise processing network 21 to obtain differential mode electromagnetic noise and common mode electromagnetic noise, respectively, and then After the two electromagnetic noise conversion networks 22 perform gain and closed-loop feedback processing, the differential mode electromagnetic noise injection network 23 passes the processed differential mode electromagnetic noise through the differential mode loop to offset the electricity generated by the subsequent stage electrical equipment in the differential mode loop.
  • the processed common mode electromagnetic noise is returned to the common mode noise source in the electrical equipment through the common mode loop through the common mode electromagnetic noise injection network 25, thereby realizing the internal circulation mode of electromagnetic noise to meet electromagnetic interference (EMI )
  • EMI electromagnetic interference
  • the electromagnetic noise processing network 21 in the third embodiment of the present invention is composed of an electromagnetic noise sampling network 213 and a differential common-mode electromagnetic noise extraction network 214.
  • the electromagnetic noise sampling network 213 is sampled by a current transformer, and the difference common mode electromagnetic noise extraction network 214 is implemented by an algebraic sum of operational amplifiers.
  • the differential mode electromagnetic noise injection network 23 in the third embodiment of the present invention uses a semiconductor transistor-based differential mode electromagnetic noise injection network; the common mode electromagnetic noise injection network 25 in the third embodiment of the present invention uses a capacitor-based common mode electromagnetic noise injection network. .
  • FIG. 28 is a schematic diagram of an active electromagnetic interference filter according to a fourth embodiment of the present invention.
  • an active electromagnetic interference filter according to the fourth embodiment of the present invention extracts electromagnetic noise generated by electrical equipment through an electromagnetic noise processing network 21 to obtain differential mode electromagnetic noise and common mode electromagnetic noise, respectively, and then After the two electromagnetic noise conversion networks 22 perform gain and closed-loop feedback processing, the differential mode electromagnetic noise injection network 23 passes the processed differential mode electromagnetic noise through the differential mode loop to offset the electricity generated by the subsequent stage electrical equipment in the differential mode loop.
  • the processed common mode electromagnetic noise is returned to the common mode noise source in the electrical equipment through the common mode loop through the common mode electromagnetic noise injection network 25, thereby realizing the internal circulation mode of electromagnetic noise to meet electromagnetic interference (EMI )
  • EMI electromagnetic interference
  • the electromagnetic noise processing network 21 in the fourth embodiment of the present invention is composed of an electromagnetic noise sampling network 213 and a differential common-mode electromagnetic noise extraction network 214.
  • the electromagnetic noise sampling network 213 performs sampling through a differential mode inductor, and the differential common mode electromagnetic noise extraction network 214 is implemented by an algebraic sum of operational amplifiers.
  • the differential mode electromagnetic noise injection network 23 in the fourth embodiment of the present invention uses a semiconductor transistor-based differential mode electromagnetic noise injection network; the common mode electromagnetic noise injection network 25 in the fourth embodiment of the present invention uses a capacitor-based common mode electromagnetic noise injection network. .
  • FIG. 29 is a schematic diagram of an active electromagnetic interference filter according to Embodiment 5 of the present invention.
  • an active electromagnetic interference filter according to the fifth embodiment of the present invention extracts electromagnetic noise generated by electrical equipment through an electromagnetic noise processing network 21 to obtain differential mode electromagnetic noise and common mode electromagnetic noise, respectively.
  • the differential mode electromagnetic noise injection network 23 passes the processed differential mode electromagnetic noise through the differential mode loop to offset the electricity generated by the subsequent stage electrical equipment in the differential mode loop.
  • the processed common mode electromagnetic noise is returned to the common mode noise source in the electrical equipment through the common mode loop through the common mode electromagnetic noise injection network 25, thereby realizing the internal circulation mode of electromagnetic noise to meet electromagnetic interference (EMI )
  • EMI electromagnetic interference
  • the electromagnetic noise processing network 21 in the fifth embodiment of the present invention is composed of an electromagnetic noise sampling network 213 and a differential common-mode electromagnetic noise extraction network 214.
  • the electromagnetic noise sampling network 213 is sampled by a current transformer, and the difference common mode electromagnetic noise extraction network 214 is implemented by an algebraic sum of operational amplifiers.
  • the differential mode electromagnetic noise injection network 23 in the fifth embodiment of the present invention uses a differential mode electromagnetic noise injection network based on a dual-winding differential mode inductance; the common mode electromagnetic noise injection network 25 in the fifth embodiment of the present invention uses a common mode inductance based common Mode electromagnetic noise is injected into the network.

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Abstract

本发明涉及一种差模电磁噪声提取网络及有源电磁干扰滤波器，该差模电磁噪声提取网络包括连接在供电系统与用电设备之间的输入线缆、电磁噪声采样网络和差模电磁噪声提取器；所述差模电磁噪声提取器用于提取并输出所述输入线缆的差模电磁噪声。

Description

差模电磁噪声提取网络及有源电磁干扰滤波器 技术领域
本发明涉及滤波技术领域，尤其是涉及一种差模电磁噪声提取网络及有源电磁干扰滤波器。
背景技术
图1是用电设备与供电系统的连接示意图。如图1所示，随着用电设备越来越普及，用电设备产生的高频电磁噪声不仅会影响周边的电子设备，而且会影响供电系统。因此，1996年欧盟推行电磁兼容(简称“EMC”)法规要求，强制要求利用公共电网的电子设备必须满足相关EMC法规限值的要求。其中，供电系统可以是交流供电系统，也可以是直流供电系统。
图2为现有无源EMI滤波器的应用示意图。如图2所示，为满足EMC法规中的电磁干扰(简称“EMI”)要求，几乎所有的用电设备都会采用由无源器件构成无源EMI滤波器，串接于用电设备和供电系统之间，以抑制用电设备中的电磁噪声，满足EMI法规限值的要求，避免影响供电系统。
无源EMI滤波器的典型结构是由共模EMI滤波器和/或差模EMI滤波器组成。图3为现有共模EMI滤波器的示意图。如图3所示，共模EMI滤波器由共模电感L cm和电容C Y组成。图4为现有差模EMI滤波器的示意图。如图4所示，差模EMI滤波器由差模电感L dm和电容C X组成。
虽然，无源EMI滤波器可以抑制电磁噪声，满足EMI法规限值的要求，避免影响周边电子设备和供电电网，但是，它的串接会导致很多问题：
其一，损耗严重：在抑制微弱的μA级电磁噪声时，需要同时承受用电设备的负载电流，从而导致额外的损耗和发热，降低用电设备的能效和可靠性；
其二，体积庞大：为承受用电设备负载电流，必然会导致共模电感和差模电感体积增大，甚至超过用电设备功能性电路的体积，变得本末倒置；
其三，成本增加：为满足不同频段的电磁噪声抑制的需要，通常需要采用不同磁材的共模电感来抑制不同频段的电磁噪声，这样必然导致多级滤波 架构，最终导致无源EMI滤波器成本增加，体积进一步增大，同时也导致更多的损耗和发热；
其四，近场耦合：由于无源器件体积大和杂散参数的影响，高频段出现电磁噪声近场耦合和谐振，造成滤波效果达不到设计预期。
图5为现有有源EMI滤波器的概念示意图。如图5所示，为解决上述传统的无源EMI滤波器的缺陷，有源EMI滤波器的概念结构被提出。有源EMI滤波器会采集后级用电设备产生的电磁噪声电流或电压信号，经增益放大后实现闭环反馈，以达到噪声抑制的目的。
另一些已知的有源EMI滤波器采用在常规的共模电感上加第3个耦合绕组来提取流经共模电感的共模电磁噪声，经过增益放大处理后，通过电容注入到包括大地或者外壳组成的共模回路，来实现共模噪声的抑制。
但是，由于共模电感的3个绕组不能达到完全耦合，总是会存在3％～5％左右的漏感，从而在耦合到共模电磁噪声的同时，也耦合到部分的差模电磁噪声，混杂在共模电磁噪声中一起被放大处理，注入到共模回路中，最后导致由于混入差模电磁噪声引起的新共模电磁噪声，从而达不到预期的共模电磁噪声的抑制效果。
一些已知的有源差模EMI滤波器，通过采样串接在直流母线上的电感电压信号来获取差模电磁噪声，再经放大处理后，控制MOSFET晶体管的阻抗来实现抑制差模噪声的目的。然而，在供电的直流母线上会包含差模电磁噪声，也同时包含共模电磁噪声。因此，从电感获取的电磁噪声中不仅包括差模电磁噪声，也包括共模电磁噪声。这样混杂共模电磁噪声的差模电磁噪声一起经放大处理后，通过MOSFET晶体管的阻抗变化，注入到差模回路中，最后导致由于混入共模电磁噪声引起新的差模电磁噪声，最后达不到预期的差模噪声抑制效果。
图6为现有标准传导干扰的测试设置图。如图6所示，依据CISP16-1-2的传导干扰的标准测试设置图，其中利用标准的线性阻抗匹配网络(简称LISN)串接于供电电网系统和用电设备之间来提取被测设备的传导干扰噪声。传导干扰测试中，接收机检测到的电磁噪声是通过线性阻抗匹配网络(简称LISN)耦合提取的。如图6所示，输入线缆11上流动的电磁噪声电流I 输入1 包括同向的1/2的共模电磁噪声电流I CM和差模电磁噪声电流I DM，而在另一根返回的输入线缆12上流动的电磁噪声电流I 输入2包括同向的1/2共模电磁噪声电流I CM和反向的差模电磁噪声电流I DM。输入线缆11和12中同向的1/2共模电磁噪声电流I CM会通过被测用电设备中的共模电磁噪声源101经传导测试中接大地的金属板返回到接收机中，从而使共模电磁噪声电流I CM被接收机检测到。被测用电设备中的差模电磁噪声源100产生差模电磁电流在输入线缆11和12中反向流动，经LISN耦合后，被接收机检测到。
图5所示的现有有源EMI滤波器的示意图既适用于抑制共模电磁噪声，也适用于抑制差模电磁噪声。但是共模电磁噪声和差模电磁噪声的传播路径不同。差模电磁噪声只会通过差模回路传播。共模电磁噪声只会通过共模路径传播，但会在输入线缆上和用电设备内部产生交叠，而且共模电磁噪声的另外一半传播路径是经过大地被电磁干扰测试的接收机检测到。因此，将用电设备中差共模噪声进行完全隔离提取和分别注入对实现差共模电磁噪声的抑制十分关键。
发明内容
本发明提供一种差模电磁噪声提取网络以及包括该差模电磁噪声提取网络的有源电磁干扰滤波器，能够使用电设备的差模电磁噪声少量甚至不进入供电系统中。
本发明的一个方面提供一种差模电磁噪声提取网络，包括适于连接在供电系统与用电设备之间的输入线缆、电磁噪声采样网络和差模电磁噪声提取器；所述电磁噪声采样网络设置在所述输入线缆与所述差模电磁噪声提取器之间，用于对所述输入线缆的差共模电磁噪声进行采样并将所采样的差共模电磁噪声输出至所述差模电磁噪声提取器；所述差模电磁噪声提取器用于提取并输出所述电磁噪声采样网络所采样的差共模电磁噪声中的差模电磁噪声。
进一步地，所述输入线缆包括并联的第一输入线缆和第二输入线缆；所述电磁噪声采样网络包括第一采样器和第二采样器；其中，所述第一采样器设置在所述第一输入线缆上，所述第一采样器与所述差模电磁噪声提取器连 接；所述第二采样器设置在所述第二输入线缆上，所述第二采样器与所述差模电磁噪声提取器连接。
进一步地，所述输入线缆包括并联的第一输入线缆和第二输入线缆；所述电磁噪声采样网络包括电感，所述电感包括两个原边绕组和两个副边采样绕组；其中，两个所述原边绕组与两个所述副边采样绕组一一对应耦合；其中一个所述原边绕组串接在所述第一输入线缆与用电设备之间，另一个所述原边绕组串接在所述第二输入线缆与用电设备之间；两个所述副边采样绕组的两个第一端均与地连接，两个所述副边采样绕组的两个第二端均用于输出对应输入线缆的差共模电磁噪声。
进一步地，所述输入线缆包括并联的第一输入线缆和第二输入线缆；所述差模电磁噪声提取器包括双绕组电感；其中，所述两个绕组的极性相同，所述差模电磁噪声提取器的两个绕组的第一端分别用于接收所述第一输入线缆和所述第二输入线缆的差共模电磁噪声，所述差模电磁噪声提取器的两个绕组的第二端均用于输出差模电磁噪声。
进一步地，所述输入线缆包括并联的第一输入线缆和第二输入线缆；所述差模电磁噪声提取器包括第二运算放大器、第五电阻、第六电阻、第七电阻和第八电阻；其中，所述第五电阻的第一端用于接收所述第一输入线缆的差共模电磁噪声，所述第五电阻的第二端与所述第二运算放大器的负极输入端和第七电阻的一端连接；所述第六电阻的第一端用于接收所述第二输入线缆的差共模电磁噪声，所述第六电阻的第二端与所述第二运算放大器的正极输入端和第八电阻的一端连接；所述第七电阻连接在所述第二运算放大器的负极输入端和输出端之间；所述第八电阻连接在所述第二运算放大器的正极输入端和地之间。
本发明提供的差模电磁噪声提取网络通过电磁噪声采样网络对输入线缆的差共模电磁噪声进行采样并将所采样的差共模电磁噪声输出至差模电磁噪声提取器，相当于差模电磁噪声提取器间接从用电设备的输入线缆中提取差模电磁噪声。在有源电磁干扰滤波器中，所提取的差模电磁噪声通过电磁噪声转换网络进行增益和闭环反馈处理。经过处理后的差模电磁噪声借助差模电磁噪声注入网络，通过差模回路返回到用电设备中的差模噪声源。如此， 用电设备的差模电磁噪声能够少量甚至不进入供电系统中，使得周边环境和供电电网不受用电设备的电磁噪声的影响，同时也能让用电设备满足EMI法规限值的要求。
本发明的另一方面还提供一种有源电磁干扰滤波器，该有源电磁干扰滤波器包括如上所述的差模电磁噪声提取网络。
进一步地，有源电磁干扰滤波器还包括电磁噪声转换网络和差模电磁噪声注入网络；所述电磁噪声转换网络用于对所述差模电磁噪声进行增益和闭环反馈处理；经过处理的所述差模电磁噪声通过所述差模电磁噪声注入网络返回到用电设备；所述差模电磁噪声提取网络、所述电磁噪声转换网络和所述差模电磁噪声注入网络依次连接。
本发明提供的有源电磁干扰滤波器相比于现有技术的有益效果，同于本发明提供的差模电磁噪声提取网络相比于现有技术的有益效果，此处不再赘述。
附图概述
为了更清楚地说明本发明具体实施方式或现有技术中的技术方案，下面将对具体实施方式或现有技术描述中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图是本发明的一些实施方式，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图获得其它的附图。
图1为用电设备与供电系统的连接示意图；
图2为现有无源EMI滤波器的应用示意图；
图3为现有共模EMI滤波器的示意图；
图4为现有差模EMI滤波器的示意图；
图5为现有有源EMI滤波器的概念示意图；
图6为现有标准传导干扰的测试设置图；
图7为本发明实施例提供的有源电磁干扰滤波器滤波技术的示意图；
图8为本发明实施例提供的电磁噪声处理网络的第一示意图；
图9为本发明实施例提供的电磁噪声处理网络的第二示意图；
图10为本发明实施例提供的电磁噪声采样网络的第一示意图；
图11为本发明实施例提供的电磁噪声采样网络的第二示意图；
图12为本发明实施例提供的电磁噪声提取网络的第一示意图；
图13为本发明实施例提供的电磁噪声提取网络的第二示意图；
图14为本发明实施例提供的基于半导体晶体管的差模电磁噪声注入网络的示意图；
图15为本发明实施例提供的基于双绕组差模电感的差模电磁噪声注入网络的示意图；
图16为本发明实施例提供的基于三绕组差模电感的差模电磁噪声注入网络的示意图；
图17为本发明实施例提供的基于电容的共模电磁噪声注入网络的示意图；
图18为本发明实施例提供的基于接地电容的共模电磁噪声注入网络的示意图；
图19为本发明实施例提供的基于电感电磁的共模电磁噪声注入网络的示意图；
图20为本发明实施例提供的一个交流输入的电源适配器简化电路图；
图21为本发明实施例提供的一个直流输入的开关电源简化电路图；
图22为本发明实施例提供的一个交流输入的电源适配器简化电路图；
图23为本发明实施例提供的一个直流输入的开关电源简化电路图；
图24为本发明实施例提供的电磁噪声转换网络的示意图；
图25为本发明实施例一提供的有源电磁干扰滤波器的示意图；
图26为本发明实施例二提供的有源电磁干扰滤波器的示意图；
图27为本发明实施例三提供的有源电磁干扰滤波器的示意图；
图28为本发明实施例四提供的有源电磁干扰滤波器的示意图；
图29为本发明实施例五提供的有源电磁干扰滤波器的示意图。
附图标记：
100-差模电磁噪声源；101-共模电磁噪声源；108-共模电磁噪声分量输出端；109-差模电磁噪声分量输出端；11-第一输入线缆；12-第二输入线缆； 111-第一输入线缆的电磁噪声；121-第二输入线缆的电磁噪声；21-电磁噪声处理网络；22-电磁噪声转换网络；23-差模电磁噪声注入网络；25-共模电磁噪声注入网络；211-共模电磁噪声提取器；212-差模电磁噪声提取器；213-电磁噪声采样器；214-差共模电磁噪声提取网络；215-第一采样器；216-第二采样器；33-第一运算放大器；34-第二运算放大器；35-第一阻容网络；36-第二阻容网络。
本发明的较佳实施方式
下面将结合附图对本发明的技术方案进行清楚、完整地描述，显然，所描述的实施例是本发明一部分实施例，而不是全部的实施例。基于本发明中的实施例，本领域普通技术人员在没有做出创造性劳动前提下所获得的所有其它实施例，都属于本发明保护的范围。
在本发明的描述中，需要说明的是，术语“中心”、“上”、“下”、“左”、“右”、“竖直”、“水平”、“内”、“外”等指示的方位或位置关系为基于附图所示的方位或位置关系，仅是为了便于描述本发明和简化描述，而不是指示或暗示所指的装置或元件必须具有特定的方位、以特定的方位构造和操作，因此不能理解为对本发明的限制。此外，术语“第一”、“第二”、“第三”仅用于描述目的，而不能理解为指示或暗示相对重要性。
在本发明的描述中，需要说明的是，除非另有明确的规定和限定，术语“安装”、“相连”、“连接”应做广义理解，例如，可以是固定连接，也可以是可拆卸连接，或一体地连接；可以是机械连接，也可以是电连接；可以是直接相连，也可以通过中间媒介间接相连，可以是两个元件内部的连通。对于本领域的普通技术人员而言，可以具体情况理解上述术语在本发明中的具体含义。
图7为本发明实施例提供的有源EMI滤波技术的示意图。参照图7所示，针对传统无源EMI滤波器和现有有源EMI滤波器的缺点，本发明实施例提出一种差共模电磁噪声分别抑制的有源EMI滤波技术，实际中以有源电磁干扰滤波器实施该技术。该有源电磁干扰滤波器包括电磁噪声处理网络21、电磁噪声转换网络22、差模电磁噪声注入网络23和共模电磁噪声注入网络25。
本发明实施例提出的有源EMI滤波技术，通过电磁噪声处理网络21从用电设备的输入线缆中分别提取差模电磁噪声和共模电磁噪声后，分别输入到电磁噪声转换网络22进行增益和闭环反馈处理，经过处理后的差模电磁噪声和共模电磁噪声分别通过差模电磁噪声注入网络23中的差模回路和共模电磁噪声注入网络25中的共模回路返回到用电设备中的差模噪声源和共模噪声源。如此，可以实现电磁噪声内部循环，让用电设备的电磁噪声少量甚至不进入供电系统中，使得周边环境和供电电网不受用电设备的电磁噪声的影响，同时也能让用电设备满足EMI法规限值的要求。
本发明实施例提出的有源EMI滤波技术具有以下关键创新点：
1.本发明实施例提出的电磁噪声处理网络21中采用独立的差模电磁噪声的提取网络，输出到后级电磁噪声转换网络22进行增益和闭环反馈处理。本发明实施例提出多种形式的差模电磁噪声提取网络来配合后级的电磁噪声转换网络22和差模电磁噪声注入网络23。
本发明实施例提出的差模电磁噪声处理网络可以实现与共模电磁噪声大于60dB的隔离度，相当于提取的差模电磁噪声中只有不到0.1％的共模电磁噪声，使得电磁噪声抑制能达到预期抑制效果。
2.本发明实施例提出的电磁噪声处理网络21中采用独立的共模电磁噪声的提取网络，输出到后级电磁噪声转换网络22进行增益和闭环反馈处理。
本发明实施例提出多种形式的共模电磁噪声提取网络，来配合后级的电磁噪声转换网络22和共模电磁噪声注入网络25。本发明实施例提出的共模电磁噪声提取网络可以实现与差模电磁噪声大于60dB的隔离度，相当于提取的共模电磁噪声中只有不到0.1％的差模电磁噪声，使得电磁噪声抑制能达到预期抑制效果。
3.本发明实施例提出的有源EMI滤波器采用独立的差模噪声注入网络23，将处理后的差模电磁噪声注入到用电设备的差模回路，通过改变差模回路中的差模阻抗来抑制差模电磁噪声。本发明实施例提出多种形式的差模电磁噪声注入网络23，将前级处理后的差模电磁噪声注入到用电设备的差模回路，通过改变差模回路中的差模阻抗，来实现电磁噪声的抑制作用。
4.本发明实施例提出的有源EMI滤波器采用独立的共模噪声注入网络 25，将处理后的共模电磁噪声注入到用电设备的共模回路，然后返回到用电设备中的共模噪声源，形成内部循环。本发明实施例提出多种形式的共模电磁噪声注入网络25，将前级处理后的共模电磁噪声注入到用电设备的共模回路，然后返回到用电设备中的共模噪声源，形成内部循环，实现电磁噪声的抑制作用。
5.本发明实施例提出的有源EMI滤波器具有差模电磁噪声注入点的灵活性，可以在从输入线缆到后级用电设备中的差模回路中的任一点注入差模电磁噪声，通过改变差模回路中的差模阻抗，实现电磁噪声的抑制作用。
6.本发明实施例提出的有源EMI滤波器具有共模电磁噪声注入点的灵活性，可以在从输入线缆到后级用电设备中的共模回路中的任一点进行注入共模电磁噪声，然后返回到用电设备中的共模电磁噪声源，形成内部循环，实现电磁噪声的抑制作用。
下面针对本发明实施例提出的多种形式的电磁噪声处理网络21、差模电磁噪声注入网络23、共模电磁噪声注入网络25以及灵活的电磁噪声注入点进行逐一阐述。
以下为电磁噪声处理网络21的多种实现方式。
本发明实施例提出的有源EMI滤波器采用的电磁噪声处理网络21包括电磁噪声提取网络，该电磁噪声提取网络有以下两种主要实现方式：直接提取网络和间接提取网络，或者对应称之为单级提取网络和两级提取网络，用于提取差模电磁噪声和共模电磁噪声。
其中，电磁噪声提取网络包括共模电磁噪声提取器和差模电磁噪声提取器；其中，共模电磁噪声提取器用于提取并输出所述输入线缆的共模电磁噪声；差模电磁噪声提取器用于提取并输出所述输入线缆的差模电磁噪声。
单级提取网络中，共模电磁噪声提取器用于直接提取并输出输入线缆的共模电磁噪声；差模电磁噪声提取器用于直接提取并输出输入线缆的差模电磁噪声。
两级提取网络中，共模电磁噪声提取器用于间接提取并输出输入线缆的共模电磁噪声；差模电磁噪声提取器用于间接提取并输出输入线缆的差模电磁噪声。
图8为本发明实施例提供的电磁噪声处理网络为单极提取网络时的示意图。参照图8所示，该单级提取网络中包括共模电磁噪声提取器211和差模电磁噪声提取器212。在一些实施例中，该共模电磁噪声提取器211和差模电磁噪声提取器212均为电流互感器。第一输入线缆11依次穿过共模电磁噪声提取器211和差模电磁噪声提取器212的内环，再连接到用电设备；第二输入线缆12穿过共模电磁噪声提取器211的内环后，沿差模电磁噪声提取器212的厚度方向环绕差模电磁噪声提取器212的环体一圈后绕出，再连接到用电设备。
由于第一输入线缆11和第二输入线缆12同时穿过共模电磁噪声提取器211的内环，根据电流环路定律，共模电磁噪声提取器211的输出电流等于其内环中的两根输入线缆的电流总和。由于I 输入1+I 输入2＝(I CM/2+I DM)+(I CM/2-I DM)＝I CM，因此，共模电磁噪声提取器211的输出电流为共模电磁噪声电流I CM。
对于差模电磁噪声提取器212来说，根据其内环中的输入线缆的方向以及线缆中流经电流的方向，可以得出差模电磁噪声提取器212的输出电流为：I 输入1-I 输入2＝(I CM/2+I DM)-(I CM/2-I DM)＝I DM。即，差模电磁噪声提取器212的输出电流为差模电磁噪声电流I DM。
共模电磁噪声提取器211输出的共模电磁噪声电流I CM和差模电磁噪声提取器212输出的差模电磁噪声电流I DM会输出到下一级的电磁噪声转换网络22中，进行增益和闭环反馈处理。
图9为本发明实施例提供的电磁噪声处理网络为两级提取网络时的示意图。参照图9所示，该两级提取网络中包括电磁噪声采样网络213和差共模电磁噪声提取网络214。其中，电磁噪声采样网络213设置在输入线缆与差共模电磁噪声提取网络214之间。电磁噪声采样网络213用于对输入线缆的差共模电磁噪声进行采样并将所采样的差共模电磁噪声输出至差共模电磁噪声提取网络214。
差共模电磁噪声提取网络214相当于图8所示的实施例中的单极提取网络，其中包括共模电磁噪声提取器211和差模电磁噪声提取器212。共模电磁噪声提取器211用于提取并输出电磁噪声采样网络213所采样的差共模电磁噪声中的共模电磁噪声，如图9中所示的共模电磁噪声分量；差模电磁噪声 提取器212用于提取并输出电磁噪声采样网络213所采样的差共模电磁噪声中的差模电磁噪声，如图9中所示的差模电磁噪声分量。
电磁噪声采样网络213提取每根输入线缆上的总体电磁噪声，然后输入到差共模电磁噪声提取网络214。差共模电磁噪声提取网络214将共模电磁噪声和差模电磁噪声进行分别隔离后，再输出到下级电磁噪声转换网络22，进行增益和闭环反馈处理。其中，每根输入线缆上的总体电磁噪声包括差模电磁噪声和共模电磁噪声。
电磁噪声采样网络213可以用多种方式对每根输入线缆中的总体电磁噪声进行采样。电磁噪声采样网络213的多种实现方式可以根据实际应用需要与后级差共模电磁噪声提取网路214的多种实现方式进行任意组合，来获得更加纯净的差模电磁噪声和共模电磁噪声，作为后级电磁噪声转换网络22的输入。
在本发明的实施例中，电磁噪声采样网络213可以采用两种实现方式。
图10为本发明实施例提供的电磁噪声采样网络的第一种实现方式示意图。参照图10所示，在第一种实现方式中，电磁噪声采样网络213包括第一采样器215和第二采样器216。其中，第一采样器215设置在第一输入线缆11上，第一采样器215与共模电磁噪声提取器211或差模电磁噪声提取器212连接；第二采样器216设置在第二输入线缆12上，第二采样器216与共模电磁噪声提取器211或差模电磁噪声提取器212连接。
在一些实施例中，第一采样器215和第二采样器216都可以是电流互感器。电流互感器对加入其中的输入线缆上的电磁噪声电流进行采样，这样获得的电磁噪声包括输入线缆中的共模电磁噪声和差模电磁噪声。
图11为本发明实施例提供的电磁噪声采样网络的第二种实现方式示意图。参照图11所示，在第二种实现方式中，电磁噪声采样网络213包括电感L 1，电感L 1包括两个原边绕组N P1和N P2和两个副边采样绕组N S1和N S2；其中，一个原边绕组N P1串接在第一输入线缆11与用电设备之间，另一个原边绕组N P2串接在第二输入线缆12与用电设备之间；两个副边采样绕组N S1和N S2与两个原边绕组N P1和N P2一一对应耦合，两个副边采样绕组N S1和N S2的两个第二端均用于输出对应输入线缆的差共模电磁噪声。
更为具体地，电磁噪声采样网络213利用电感加耦合绕组来获得每根输入线缆上的电磁噪声，其中电感L 1由4个绕组组成，分别是原边绕组N P1和N P2，副边采样绕组N S1和N S2，原边绕组N P1与副边采样绕组N S1采用紧耦合的绕线方式以达到高耦合度；原边绕组N P2与副边采样绕组N S2采用紧耦合的绕线方式以达到高耦合度。
原边绕组N P1串接于第一输入线缆11和用电设备输入之间，原边绕组N P2串接于第二输入线缆12和用电设备输入之间。副边采样绕组N S1和N S2一端接地后，另一端输出耦合到对应输入线缆的电磁噪声。这样获得的电磁噪声会包括线缆中的共模电磁噪声和差模电磁噪声。
差共模电磁噪声提取网路214的实现方式如下：
差共模电磁噪声提取网路214可以用多种形式进行隔离，以获得更加纯净的差模电磁噪声和共模电磁噪声，作为后级电磁噪声转换网络22的输入。差共模电磁噪声提取网路214的多种实现方式可以参考前级电磁噪声采样网络213的多种实现方式，根据实际应用需要进行任意组合，来获得更加纯净的差模电磁噪声和共模电磁噪声，作为后级电磁噪声转换网络22的输入。
差共模电磁噪声提取网路214的实现方式有两种：绕组感应电压抵消方式和运算放大器代数和方式。
图12为本发明实施例提供的电磁噪声提取网络的第一示意图。参照图12所示，差共模电磁噪声提取网络214可以通过磁性器件的绕组感应电压抵消方式实现，以获得更加纯净的差模电磁噪声和共模电磁噪声。其中，共模电磁噪声提取器和差模电磁噪声提取器均为双绕组电感，分别为L 1和L 2。其中，共模电磁噪声提取器采用的双绕组电感L 1的两个绕组的极性相反，共模电磁噪声提取器的两个绕组的第一端分别用于接收第一输入线缆11和第二输入线缆12的差共模电磁噪声，共模电磁噪声提取器的两个绕组的第二端均用于输出共模电磁噪声；差模电磁噪声提取器采用的双绕组电感L 2的两个绕组的极性相同，差模电磁噪声提取器的两个绕组的第一端分别用于接收第一输入线缆11和第二输入线缆12的差共模电磁噪声，差模电磁噪声提取器采用的双绕组电感L 1和双绕组电感L 2的两个绕组的第二端均用于输出差模电磁噪声。
首先，把双绕组电感L 1的两个绕组极性相反的一端分别连接至前级电磁 噪声采样网络213输出的第一输入线缆11的电磁噪声111和第二输入线缆12的电磁噪声121；双绕组电感L 1的两个绕组的另外一端相连后作为共模电磁噪声输出。
由于第一输入线缆11和第二输入线缆12中的共模电流是同向的，而第一输入线缆11和第二输入线缆12中的差模电流是反向相对的，因此，根据磁学原理，第一输入线缆11和第二输入线缆12的同向共模电流在双绕组电感L 1中磁芯的绕组中产生的感应电压相互抵消，换言之，对共模电流没有抑制作用，反之对差模电流有抑制作用。因此，通过双绕组电感L 1这样的连接方式可以隔离掉差模电磁噪声，而获得纯净的共模电磁噪声。
按照上述隔离差模电磁噪声的原理，也可以隔离共模电磁噪声。首先，把双绕组电感L 2的两个绕组极性相同的一端分别连接至前级电磁噪声采样网络3213输出的第一输入线缆11的电磁噪声111和第二输入线缆12的电磁噪声121；双绕组电感L 2的两个绕组的另外一端相连后作为差模电磁噪声输出。
第一输入线缆11和第二输入线缆12中的差模电流是反向相对的，而第一输入线缆11和第二输入线缆12中的共模电流是同向的。因此，根据磁学原理，第一输入线缆11和第二输入线缆12的同向差模电流在双绕组电感L 2中磁芯的绕组中产生的感应电压相互抵消，换言之，对差模电流没有抑制作用，反之对共模电流有抑制作用。因此，通过双绕组电感L 2这样的连接方式可以隔离掉共模电磁噪声，而获得纯净的差模电磁噪声。
图13为本发明实施例提供的电磁噪声提取网络的第二示意图。参照图13所示，差共模电磁噪声提取网路214也可以用运算放大器对数和的方式来实现，以获得更加纯净的差模电磁噪声和共模电磁噪声。
共模电磁噪声的输出由第一运算放大器33、第一电阻R 1、第二电阻R 2、第三电阻R 3和第四电阻R 4来实现隔离差模电磁噪声的目的。第一运算放大器33的负极输入端与电阻R 1、R 2和R 3相连，第一运算放大器33的正极输入端与第四电阻R 4相连，经第四电阻R 4后与地相连；第一运算放大器33的输出端与第三电阻R 3相连，同时作为共模电磁噪声分量输出端108，第一电阻R 1的另一端与第一输入电缆11的电磁噪声111相连；第二电阻R 2的另一端与第二输入电缆12的电磁噪声121相连。根据运算放大器和电阻网络的连接方式可以 实现代数加法，将第一输入线缆11的电磁噪声电流I 输入1和第二输入线缆12的电磁噪声电流I 输入2进行代数加法I 输入1+I 输入2，如此获取共模电磁噪声I CM，隔离掉差模电磁噪声I DM。
依据上述获得共模电磁噪声的方法，还可以实现减法来获取差模电磁噪声，同时隔离掉共模电磁噪声。
差模电磁噪声的输出由第二运算放大器34、第五电阻R 5、第六电阻R 6、第七电阻R 7和第八电阻R 8来实现隔离共模电磁噪声的目的。第二运算放大器34的负极输入端与第五电阻R 5和第七R 7相连；第二运算放大器34的正极输入端与第六电阻R 6和第八电阻R 8相连，经第八电阻R 8后与地相连；第二运算放大器34的输出端与第七电阻R 7相连，同时作为差模电磁噪声分量输出端109；第五电阻R 5的另一端与第一输入电缆11的电磁噪声111相连；第五电阻R 6的另一端与第二输入电缆12的电磁噪声121相连。
根据运算放大器和电阻网络的连接方式可以实现代数减法，将第一输入线缆11的电磁噪声电流I 输入1和第二输入线缆12的电磁噪声电流I 输入2进行代数减法I 输入1-I 输入2，如此可以获取差模电磁噪声I DM，隔离掉共模电磁噪声I CM。
上述阐述的“运算放大器的代数和”实现方式为将输入线缆中的共模电磁噪声和差模电磁噪声实现代数加法和代数减法的实现方式之一。
其中，本实施例附图中所涉及的+Vcc和-Vcc分别表示正电源和负电源。
以下为差模电磁噪声注入网络23的多种实现方式。
差模电磁噪声注入网络23可以用多种方式实现，包括：半导体晶体管和差模电感的形式。
图14为本发明实施例提供的基于半导体晶体管的差模电磁噪声注入网络的示意图。参照图14所示，在基于半导体晶体管的差模电磁噪声注入网络23中，半导体晶体管为场效应晶体管Q 1，其漏极连接至第一输入线缆11，其源极连接至用电设备，其门极连接至前级电磁噪声转换网络22的差模电磁噪声分量输出端109。
本发明实施例提出的有源EMI滤波器可以利用晶体管Q 1的门极电压变化来调节第一输入线缆11上的差模阻抗，从而实现抑制差模电磁噪声的目的。
由于第一输入线缆11和第二输入线缆12处在同一个差模回路中，因此，场效应晶体管Q 1可以放置在差模回路中任意位置，都可以起到抑制差模电磁噪声的目的。比如放置在第二输入线缆12上，或者在后级用电设备的差模回路中。
图15为本发明实施例提供的基于双绕组差模电感的差模电磁噪声注入网络的示意图。参照图15所示，在基于双绕组差模电感的差模电磁噪声注入网络23中，差模电感L 3具有两个绕组：原边绕组N P和副边绕组N S；双绕组差模电感L 3的原边绕组N P一端连接前级电磁噪声转换网络22的差模电磁噪声分量输出端109，另一端做接地处理；双绕组差模电感L 3的副边绕组N S的一端接第一输入线缆11，另一端接后级用电设备。
本发明实施例提出的有源EMI滤波器可以利用双绕组差模电感L 3的原边绕组N P将前级电磁噪声转换网络22的差模分量耦合到双绕组差模电感L 3的副边绕组N S所在的差模回路中，来改变差模回路的差模阻抗，从而实现抑制差模噪声的目的。
图16为本发明实施例提供的基于三绕组差模电感的差模电磁噪声注入网络的示意图。参照图16所示，在基于三绕组差模电感的差模电磁噪声注入网络中，三绕组差模电感L 4具有三个绕组：原边绕组N P1、第一副边绕组N S1和第二副边绕组N S2；三绕组差模电感L 4的原边绕组N P1一端连接前级电磁噪声转换网络22的差模电磁噪声分量输出端109，另一端做接地处理；三绕组差模电感L 4的第一副边绕组N S1的一端接第一输入线缆11，另一端接后级用电设备；三绕组差模电感L 4的第二副边绕组N S2的一端接第二输入线缆12，另一端接后级用电设备。
本发明实施例提出的有源电磁干扰滤波器可以利用三绕组差模电感L 4的原边绕组N P1将前级电磁噪声转换网络22的差模电磁噪声分量输出端109耦合到三绕组差模电感L 4的第一副边绕组N S1和第二副边绕组N S2所在的差模回路中，来改变差模回路的差模阻抗，从而实现抑制差模噪声的目的。
以下为共模噪声注入网络25的实现方式。
共模噪声注入网络25也可以用多种方式实现，包括：基于电容的共模噪声注入网络25、基于接地电容的共模噪声注入网络25和基于共模电感的共模 噪声注入网络25。
图17为本发明实施例提供的基于电容的共模电磁噪声注入网络的示意图。参照图17所示，在基于电容的共模噪声注入网络25中，第一电容C 1，第二电容C 2和第三电容C 3的一端相连到一起；第一电容C 1的另一端与第一输入线缆11和后级用电设备相连，第二电容C 2的另一端与第二输入线缆12和后级用电设备相连；第三电容C 3的另一端与前级电磁噪声转换网络22的共模电磁噪声分量输出端108相连。
本发明实施例提出的有源EMI滤波器可以通过第一电容C 1、第二电容C 2和第三电容C 3将前级电磁噪声转换网络22的共模电磁噪声分量输出端108注入到共模回路中，从而让共模电流回到后级用电设备中，起到抑制共模电磁噪声的目的，同时实现让EMI接收机检测少量、甚至不能检测到共模噪声。
基于电容的共模噪声注入网络25的连接方式由于不需要涉及大地，因此不仅可以适用于输入带大地的I类用电设备，也适用于输入不带大地的II类用电设备，以及直流供电的用电设备。
图18为本发明实施例提供的基于接地电容的共模电磁噪声注入网络的示意图。参照图18所示，在基于接地电容的共模噪声注入网络25中，第四电容C 4的一端连接前级电磁噪声转换网络22的共模电磁噪声分量输出端108，另一端接大地或者用电设备的外壳。
本发明实施例提出的有源EMI滤波器可以通过第四电容C 4将前级电磁噪声转换网络22的共模输出分量注入到共模噪声回路，让共模电磁噪声尽早地返回共模噪声源，可以少量甚至不被EMI接收机检测到共模噪声。
图19为本发明实施例提供的基于共模电磁的共模电磁噪声注入网络的示意图。参照图19所示，在基于共模电感的共模噪声注入网络25中，共模电感L 5有三个绕组：原边绕组N P1、第一副边绕组N S1和第二副边绕组N S2。共模电感L 5的原边绕组N P1的一端连接前级电磁噪声转换网络22的共模电磁噪声分量输出端108，另一端接地；共模电感L 5的第一副边绕组N S1一端连接至第一输入线缆11，另一端连接至用电设备；共模电感L 5的第二副边绕组N S2的一端连接至第二输入线缆12，另一端连接至用电设备。
本发明实施例提出的有源电磁干扰滤波器可以通过电感L 5的原边绕组 N P1将前级电磁噪声转换网络22的共模输出分量，经电感L 5的副边绕组N S1和N S2注入到共模噪声回路，来抵消共模回路中共模电流，可以减少被EMI接收机检测到共模噪声。
本发明实施例提出的差模电磁噪声注入网络23的注入点可以是差模回路中的任意位置，都可以实现差模电磁噪声的抑制作用。本发明实施例中提到的差模回路指差模电流I DM流经的用电设备内部的器件、回路和输入线缆。
图20为本发明实施例提供的一个交流输入的电源适配器简化电路图。参照图20所示，黑色箭头指示的回路为差模电流I DM流经的差模回路，从火线L、整流桥BD1、电容C 1到零线N，同时包括器件间的连线。本发明实施例提出的差模电磁噪声注入点在图20所示的电路中可以选择A、B、C和D所标示的四个点进行注入，其中A点为火线L，B点为整流桥BD1正极与电容C 1的连线，C点为整流桥BD1负极与电容C 1的连线，D点为零线N。
当采用三绕组差模电感的差模电磁噪声注入网络23进行差模电磁噪声注入时，可以考虑A/D两点作为三绕组差模电感的两个副边绕组的插入点，或者B/C两点作为三绕组差模电感的两个副边绕组的插入点。
图21为本发明实施例提供的一个直流输入的开关电源简化电路图。参照图21所示，黑色箭头指示的回路为差模电流I DM流经的差模回路。差模回路从输入正极连线，电容C 1到输入负极连线。本发明实施例提出的差模电磁噪声注入点在图21中可以选择A点和B点进行注入。A点为输入正极的连线，B点为输入负极的连线。
当采用三绕组差模电感的差模电磁噪声注入网络23进行差模电磁噪声注入时，可以考虑A/B两点作为三绕组差模电感的两个副边绕组的插入点。
共模电磁噪声注入网络25的注入点可以在共模回路中的任意位置，都可以实现共模电磁噪声的抑制作用。本发明提到的共模回路指共模电流I CM流经的用电设备内部的器件、回路、输入线缆和大地。
图22为本发明实施例提供的一个交流输入的电源适配器简化电路图。参照图22所示，黑色箭头指示为共模电流I CM流经的共模回路。共模回路从火线L，零线N，整流桥BD1正极与电容C 1的连线，整流桥BD1负极与电容C 1的连线，晶体管Q 1的漏极，以及漏极与大地的寄生电容C 寄，进入大地；另一 个共模回路从变压器连接整流二极管的阳极与大地的寄生电容C 寄，进入大地。
本发明实施例提出的共模电磁噪声注入网络25的注入点可以选择A、B、C和D点，不像差模电磁噪声注入网络23可以选择单点进行注入，共模电磁噪声注入网络25的注入点必须选择配对注入。当采用图17所示的基于电容的共模电磁噪声注入网络25时，必须同时选用A点和B点作为电容C 1和电容C 2的连接点。同样，当采用三绕组共模电感的共模电磁噪声注入网络25时，必须同时在A点和B点插入共模电感的副边绕组。
图23为本发明实施例提供的一个直流输入的开关电源简化电路图。参照图23所示，黑色箭头指示的回路为共模电流I CM流经的共模回路。共模回路从输入正极与电容C 1的连线，输入负极与电容C 1的连线，电容C 1与晶体管Q 1漏极的连线，电容C 1与晶体管Q 2源极的连线，晶体管Q 1和晶体管Q 2桥臂中点与大地间的寄生电容C 寄，晶体管Q 3和晶体管Q 4桥臂中点与大地间的寄生电容C 寄，变压器T 1，变压器T 1与大地间的寄生电容C 寄以及大地。
本发明实施例提出的共模电磁噪声注入网络25的注入点可以选择A、B、C和D点，不像差模电磁噪声注入网络23可以选择单点进行注入，共模电磁噪声注入网络25的注入点必须选择配对注入。当采用基于电容的共模电磁噪声注入网络25时，必须同时选用A点和B点作为电容C 1和电容C 2的连接点。同样，当采用基于三绕组共模电感的共模电磁噪声注入网络25时，必须同时在A点和B点插入共模电感的副边绕组。
图24为本发明实施例提供的电磁噪声转换网络的示意图。参照图8至图24所示，本发明实施例提出的电磁噪声转换网络22的主要功能是将前级电磁噪声处理网络21输出的差模电磁噪声和共模电磁噪声进行放大和闭环反馈处理，再输出给后级的差模电磁噪声注入网络23和共模电磁噪声注入网络25。电磁噪声转换网络22可以用运算放大器、第一阻容网络35和第二阻容网络36来实现增益放大和闭环反馈。电磁噪声转换网络22可以通过调整第一阻容网络35和第二阻容网络36中电阻和电容值进行增益调整和相位调整，来实现抑制电磁噪声需要的增益和相位。
本发明实施例提出的多种形式的电磁噪声提取网络22、差模噪声注入网络23、共模噪声注入网络25以及处理后差模电磁噪声和共模电磁噪声的注入 点可以根据实际应用需要进行任意组合。
本发明实施例提出的有源EMI滤波技术不仅适用于交流供电系统，也适用于直流供电系统。
本发明实施例提出的有源EMI滤波技术适用于带地线输入的I类用电设备，也适用于无地线输入的II类用电设备。
实施例一
图25为本发明实施例一提供的有源电磁干扰滤波器的示意图。参照图25所示，本发明实施例一提出一种有源电磁干扰滤波器，实施例一通过电磁噪声处理网络21提取用电设备产生的电磁噪声，分别获得差模电磁噪声和共模电磁噪声，再分别经过两个电磁噪声转换网络22进行增益和闭环反馈处理后，通过差模电磁噪声注入网络23将处理后的差模电磁噪声通过差模回路来抵消差模回路中后级用电设备产生的差模噪声，同时借助共模电磁噪声注入网络25将处理后的共模电磁噪声通过共模回路返回到用电设备中的共模噪声源，从而实现电磁噪声内部循环方式，满足电磁干扰(EMI)法规限值的要求，使得供电系统及周边环境不受用电设备产生的电磁噪声影响。
本发明实施例一中的电磁噪声处理网络21由两个电流互感器组成，分别获得差模电磁噪声产生的差模电流I DM和共模电磁噪声产生的共模电流I CM。
本发明实施例一中的差模电磁噪声注入网络23采用基于半导体晶体管的差模电磁噪声注入网络；本发明实施例一中的共模电磁噪声注入网络25采用基于电容的共模电磁噪声注入网络。
实施例二
图26为本发明实施例二提供的有源电磁干扰滤波器的示意图。参照图26所示，本发明实施例二提出一种有源电磁干扰滤波器，通过电磁噪声处理网络21提取用电设备产生的电磁噪声，分别获得差模电磁噪声和共模电磁噪声，再分别经过两个电磁噪声转换网络22进行增益和闭环反馈处理后，通过差模电磁噪声注入网络23将处理后的差模电磁噪声通过差模回路来抵消差模回路中后级用电设备产生的差模噪声，同时借助共模电磁噪声注入网络25将处理后的共模电磁噪声通过共模回路返回到用电设备中的共模噪声源，从而实现电磁噪声内部循环方式，满足电磁干扰(EMI)法规限值的要求，使得供电系统 及周边环境不受用电设备产生的电磁噪声影响。
本发明实施例二中的电磁噪声处理网络21由电磁噪声采样网络213和差共模电磁噪声提取网络214组成。其中，电磁噪声采样网络213通过电流互感器进行采样。差共模电磁噪声提取网络214采用磁抵消方式进行差模电磁噪声和共模电磁噪声的提取。
本发明实施例二中的差模电磁噪声注入网络23采用基于半导体晶体管的差模电磁噪声注入网络；本发明实施例二中的共模电磁噪声注入网络25采用基于电容的共模电磁噪声注入网络。
实施例三
图27为本发明实施例三提供的有源电磁干扰滤波器的示意图。参照图27所示，本发明实施例三提出的一种有源电磁干扰滤波器，通过电磁噪声处理网络21提取用电设备产生的电磁噪声，分别获得差模电磁噪声和共模电磁噪声，再分别经过两个电磁噪声转换网络22进行增益和闭环反馈处理后，通过差模电磁噪声注入网络23将处理后的差模电磁噪声通过差模回路来抵消差模回路中后级用电设备产生的差模噪声，同时借助共模电磁噪声注入网络25将处理后的共模电磁噪声通过共模回路返回到用电设备中的共模噪声源，从而实现电磁噪声内部循环方式，满足电磁干扰(EMI)法规限值的要求，使得供电系统及周边环境不受用电设备产生的电磁噪声影响。
本发明实施例三中的电磁噪声处理网络21由电磁噪声采样网络213和差共模电磁噪声提取网络214组成。其中电磁噪声采样网络213通过电流互感器进行采样，差共模电磁噪声提取网络214通过运算放大器代数和的方式实现。
本发明实施例三中的差模电磁噪声注入网络23采用基于半导体晶体管的差模电磁噪声注入网络；本发明实施例三中的共模电磁噪声注入网络25采用基于电容的共模电磁噪声注入网络。
实施例四
图28为本发明实施例四提供的有源电磁干扰滤波器的示意图。参照图28所示，本发明实施例四提出的一种有源电磁干扰滤波器，通过电磁噪声处理网络21提取用电设备产生的电磁噪声，分别获得差模电磁噪声和共模电磁噪 声，再分别经过两个电磁噪声转换网络22进行增益和闭环反馈处理后，通过差模电磁噪声注入网络23将处理后的差模电磁噪声通过差模回路来抵消差模回路中后级用电设备产生的差模噪声，同时借助共模电磁噪声注入网络25将处理后的共模电磁噪声通过共模回路返回到用电设备中的共模噪声源，从而实现电磁噪声内部循环方式，满足电磁干扰(EMI)法规限值的要求，使得供电系统及周边环境不受用电设备产生的电磁噪声影响。
本发明实施例四中的电磁噪声处理网络21由电磁噪声采样网络213和差共模电磁噪声提取网络214组成。其中电磁噪声采样网络213通过差模电感进行采样，差共模电磁噪声提取网络214通过运算放大器代数和的方式实现。
本发明实施例四中的差模电磁噪声注入网络23采用基于半导体晶体管的差模电磁噪声注入网络；本发明实施例四中的共模电磁噪声注入网络25采用基于电容的共模电磁噪声注入网络。
实施例五
图29为本发明实施例五提供的有源电磁干扰滤波器的示意图。参照图29所示，本发明实施例五提出的一种有源电磁干扰滤波器，通过电磁噪声处理网络21提取用电设备产生的电磁噪声，分别获得差模电磁噪声和共模电磁噪声，再分别经过两个电磁噪声转换网络22进行增益和闭环反馈处理后，通过差模电磁噪声注入网络23将处理后的差模电磁噪声通过差模回路来抵消差模回路中后级用电设备产生的差模噪声，同时借助共模电磁噪声注入网络25将处理后的共模电磁噪声通过共模回路返回到用电设备中的共模噪声源，从而实现电磁噪声内部循环方式，满足电磁干扰(EMI)法规限值的要求，使得供电系统及周边环境不受用电设备产生的电磁噪声影响。
本发明提出实施例五中的电磁噪声处理网络21由电磁噪声采样网络213和差共模电磁噪声提取网络214组成。其中电磁噪声采样网络213通过电流互感器进行采样，差共模电磁噪声提取网络214通过运算放大器代数和的方式实现。
本发明实施例五中的差模电磁噪声注入网络23采用基于双绕组差模电感的差模电磁噪声注入网络；本发明实施例五中的共模电磁噪声注入网络25采用基于共模电感的共模电磁噪声注入网络。
最后应说明的是：以上各实施例仅用以说明本发明的技术方案，而非对其限制；尽管参照前述各实施例对本发明进行了详细的说明，本领域的普通技术人员应当理解：其依然可以对前述各实施例所记载的技术方案进行修改，或者对其中部分或者全部技术特征进行等同替换；而这些修改或者替换，并不使相应技术方案的本质脱离本发明各实施例技术方案的范围。

Claims (7)

  1. 一种差模电磁噪声提取网络，其特征在于，包括适于连接在供电系统与用电设备之间的输入线缆、电磁噪声采样网络和差模电磁噪声提取器；
    所述电磁噪声采样网络设置在所述输入线缆与所述差模电磁噪声提取器之间，用于对所述输入线缆的差共模电磁噪声进行采样并将所采样的差共模电磁噪声输出至所述差模电磁噪声提取器；
    所述差模电磁噪声提取器用于提取并输出所述电磁噪声采样网络所采样的差共模电磁噪声中的差模电磁噪声。
  2. 根据权利要求1所述的差模电磁噪声提取网络，其特征在于，所述输入线缆包括并联的第一输入线缆和第二输入线缆；
    所述电磁噪声采样网络包括第一采样器和第二采样器；其中，
    所述第一采样器设置在所述第一输入线缆上，所述第一采样器与所述差模电磁噪声提取器连接；
    所述第二采样器设置在所述第二输入线缆上，所述第二采样器与所述差模电磁噪声提取器连接。
  3. 根据权利要求1所述的差模电磁噪声提取网络，其特征在于，所述输入线缆包括并联的第一输入线缆和第二输入线缆；
    所述电磁噪声采样网络包括电感，所述电感包括两个原边绕组和两个副边采样绕组；其中，
    两个所述原边绕组与两个所述副边采样绕组一一对应耦合；
    其中一个所述原边绕组串接在所述第一输入线缆与用电设备之间，另一个所述原边绕组串接在所述第二输入线缆与用电设备之间；
    两个所述副边采样绕组的两个第一端均与地连接，两个所述副边采样绕组的两个第二端均用于输出对应输入线缆的差共模电磁噪声。
  4. 根据权利要求1所述的差模电磁噪声提取网络，其特征在于，所述输入线缆包括并联的第一输入线缆和第二输入线缆；
    所述差模电磁噪声提取器包括双绕组电感；其中，
    所述双绕组电感中的两个绕组的极性相同，所述差模电磁噪声提取器的两个绕组的第一端分别用于接收所述第一输入线缆和所述第二输入线缆的差 共模电磁噪声，所述差模电磁噪声提取器的两个绕组的第二端均用于输出差模电磁噪声。
  5. 根据权利要求1所述的差模电磁噪声提取网络，其特征在于，所述输入线缆包括并联的第一输入线缆和第二输入线缆；
    所述差模电磁噪声提取器包括第二运算放大器、第五电阻、第六电阻、第七电阻和第八电阻；其中，
    所述第五电阻的第一端用于接收所述第一输入线缆的差共模电磁噪声，所述第五电阻的第二端与所述第二运算放大器的负极输入端和第七电阻的一端连接；所述第六电阻的第一端用于接收所述第二输入线缆的差共模电磁噪声，所述第六电阻的第二端与所述第二运算放大器的正极输入端和第八电阻的一端连接；所述第七电阻连接在所述第二运算放大器的负极输入端和输出端之间；所述第八电阻连接在所述第二运算放大器的正极输入端和地之间。
  6. 一种有源电磁干扰滤波器，其特征在于，包括如权利要求1-5中任一项所述的差模电磁噪声提取网络。
  7. 根据权利要求6所述的有源电磁干扰滤波器，其特征在于，还包括电磁噪声转换网络和差模电磁噪声注入网络；
    所述电磁噪声转换网络用于对所述差模电磁噪声进行增益和闭环反馈处理；
    经过处理的所述差模电磁噪声通过所述差模电磁噪声注入网络返回到用电设备；
    所述差模电磁噪声提取网络、所述电磁噪声转换网络和所述差模电磁噪声注入网络依次连接。
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