CN114157134B - Common mode active filter with simplified structure - Google Patents
Common mode active filter with simplified structure Download PDFInfo
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- CN114157134B CN114157134B CN202111510689.9A CN202111510689A CN114157134B CN 114157134 B CN114157134 B CN 114157134B CN 202111510689 A CN202111510689 A CN 202111510689A CN 114157134 B CN114157134 B CN 114157134B
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- circuit
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- signal
- common mode
- noise
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- 230000007935 neutral effect Effects 0.000 claims abstract description 29
- 238000005070 sampling Methods 0.000 claims abstract description 22
- 230000001629 suppression Effects 0.000 claims abstract description 12
- 238000010276 construction Methods 0.000 claims abstract description 8
- 239000003990 capacitor Substances 0.000 claims description 25
- 230000003321 amplification Effects 0.000 claims description 3
- 238000003199 nucleic acid amplification method Methods 0.000 claims description 3
- 238000000034 method Methods 0.000 claims description 2
- 238000010586 diagram Methods 0.000 description 4
- 230000003071 parasitic effect Effects 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 229910002601 GaN Inorganic materials 0.000 description 1
- JMASRVWKEDWRBT-UHFFFAOYSA-N Gallium nitride Chemical compound [Ga]#N JMASRVWKEDWRBT-UHFFFAOYSA-N 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000005764 inhibitory process Effects 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000005457 optimization Methods 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 description 1
- 229910010271 silicon carbide Inorganic materials 0.000 description 1
- 230000001052 transient effect Effects 0.000 description 1
Classifications
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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
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
- Y02E40/40—Arrangements for reducing harmonics
Abstract
The invention discloses a common mode active filter with a simplified structure, which mainly comprises a neutral point construction circuit, a noise signal sampling circuit, a noise signal amplifying circuit and a noise signal compensation circuit. The neutral point generated by the neutral point construction circuit is used as a reference point of the common mode active filter circuit with the simplified structure. After the common-mode interference signal is sampled by the noise signal sampling circuit, the common-mode interference signal is amplified by the noise signal amplifying circuit, and finally, a corresponding compensation signal is generated on the noise signal compensation circuit. The generated compensation signal can be mutually counteracted with a common mode interference signal in the circuit, so that the purpose of noise suppression is achieved. The invention can effectively inhibit common-mode interference signals through fewer components and parts and with smaller circuit volume, thereby realizing the miniaturization design of the active filter.
Description
Technical Field
The invention relates to the field of electromagnetic compatibility, in particular to a common mode active filter with a simplified structure and an implementation circuit thereof.
Background
Low volume, high switching frequency, high power and high power density have been the targets pursued by the development of power electronics technology. With the advent and application of new generation semiconductor devices, such as silicon carbide devices and gallium nitride devices, the switching frequency of power electronics has been significantly increased, which has led to a reduction in the size of power electronics and a significant increase in power density. However, higher switching frequencies and smaller volumes may make the electromagnetic interference problem more pronounced. In the transient state of the high-speed switch of the switching device, extremely fast voltage and current abrupt changes can be generated, and the electromagnetic environment of the circuit is seriously deteriorated by the high-speed voltage and current abrupt changes.
In order to suppress the conducted electromagnetic interference in the circuit, a conventional scheme is to reduce the amplitude of the conducted electromagnetic interference by adding a passive filter composed of passive filter elements. The method has the advantages of simplicity, reliability and easy realization in application. However, the huge volume of the passive filter element cannot meet the miniaturization requirement of the power electronic equipment. In addition, the passive filter element itself has abundant parasitic parameters, which can significantly reduce the noise suppression capability of the passive filter in the high frequency band.
At present, measures for conducting electromagnetic interference suppression by using an active filter instead of a passive filter have been proposed by the scholars. Passive filters block and bypass noise by creating multiple high and low impedance loops, mainly through different combinations of inductance and capacitance. The working principle of the active filter is different from that of the passive filter, and the active filter mainly realizes noise suppression by injecting compensation signals with the same amplitude and opposite phases with the original noise signals into the circuit. Therefore, the active filter has the advantages of small volume, light weight and strong noise suppression capability compared with the traditional passive filter.
However, the current implementation of the active filter is single, and the number of devices is more required, which makes further optimization of the active filter difficult. To improve this problem, the present invention proposes an active filter topology with a reduced structure.
Disclosure of Invention
In order to improve the problems, the invention provides a common mode active filter circuit with a simplified structure, which can realize the suppression of common mode electromagnetic interference with fewer components and smaller volume.
The invention provides a common mode active filter circuit with a simplified structure, which comprises:
the neutral point construction circuit is connected with the power supply end of the circuit system, and the neutral point construction circuit generates a neutral point, the potential of the neutral point is equal to the midpoint of the potential of the power supply end of the circuit system, and the neutral point construction circuit is used as a potential reference point of the common mode active filter circuit with the simplified structure. The noise signal sampling circuit samples a common mode interference signal between the neutral point and a ground of the circuitry. The noise signal sampling circuit is connected with the signal input end of the noise signal amplifying circuit and sends the sampled common-mode interference signal to the noise signal amplifying circuit. The input end of the noise signal amplifying circuit is connected with the noise signal sampling circuit, so that the common mode interference signal acquired by the noise signal sampling circuit can be processed, and an output signal capable of compensating the common mode interference signal in the circuit is generated. The output end of the noise signal amplifying circuit is connected with the noise signal compensating circuit. One end of the noise signal compensation circuit is connected with the output end of the noise signal amplifying circuit, and the other end of the noise signal compensation circuit is connected with the ground wire of the circuit system. The noise signal compensation circuit can convert the output signal generated by the noise signal amplification circuit into a compensation signal to be injected into a circuit system, and the final compensation signal can be mutually counteracted with a common mode interference signal existing in the circuit in a current mode, so that the purpose of noise suppression is achieved.
Drawings
Fig. 1 is a schematic diagram of connection of a common mode active filter circuit with a simplified structure in application according to the present invention.
Fig. 2 is a schematic diagram of a common mode active filter with a simplified structure according to the present invention.
Fig. 3 shows the actual measurement result of the suppression of the common-mode interference signal by the common-mode active filter with the simplified structure.
Detailed Description
In the technical scheme provided by the embodiment of the invention, the common mode active filter circuit with the simplified structure mainly comprises a neutral point construction circuit, a noise signal sampling circuit, a noise signal amplifying circuit and a noise signal compensation circuit. The neutral point generated by the neutral point construction circuit is used as a reference point of the common mode active filter circuit with the simplified structure. After the common-mode interference signal is sampled by the noise signal sampling circuit, the common-mode interference signal is amplified by the noise signal amplifying circuit, and finally, a corresponding compensation signal is generated on the noise signal compensation circuit. The generated compensation signal can be mutually counteracted with a common mode interference signal in the circuit, so that the purpose of noise suppression is achieved.
Example 1
Referring to fig. 1, fig. 1 is a schematic diagram illustrating connection of a common mode active filter circuit with a simplified structure in application according to the present invention. The embodiment of the invention provides a common mode active filter circuit with a simplified structure, wherein the common mode active filter with the simplified structure is connected with an input end bus and is in parallel connection with a post-stage power electronic converter. In addition, the common mode active filter with a simplified structure is connected with the ground line of the input end of the circuit system and has an additional neutral point.
Referring to fig. 2, a schematic circuit diagram of the common mode active filter with a simplified structure according to the present invention is shown in detail, which includes a battery pack, an artificial power network, a common mode active filter with a simplified structure, and a power electronic converter.
The battery pack is a circuit system input end, and a cathode and an anode output by the battery pack are used for supplying power to the circuit system and are respectively and directly connected with two input terminals on the left side of the artificial power supply network.
The artificial power network is a conductive interference testing instrument and can test conductive interference signals in a circuit. The artificial power network has five terminals, the left two input terminals are connected directly to the cathode and anode of the battery, the right two output terminals are connected directly to the post-stage power electronic converter, and the fifth terminal is connected to the ground line of the circuit system.
The power electronic converter is a typical flyback converter, the input end of the converter is directly connected with two output terminals on the right side of an artificial power supply network, and the main source for generating common-mode interference signals in the converter is a switching device S 1 And a switching device S 1 Parasitic capacitance C to ground p 。
The common mode active filter circuit with the simplified structure is connected between the artificial power network and the flyback converter and is in parallel connection with the flyback converter. Capacitor C 1 And capacitor C 2 Form a neutral point structure circuit and a capacitor C 1 And capacitor C 2 Connected in series and capacitance C 1 And capacitor C 2 Is the neutral point of the common mode active filter with a simplified structure. Capacitor C 1 One end of the capacitor C is connected with an output terminal on the right side of the artificial power supply network 2 . Capacitor C 2 One end of the capacitor C is connected with the other output terminal on the right side of the artificial power supply network 1 . Resistor R s And capacitor C s And the noise signal sampling circuits are formed together. Resistor R s One end is connected with the neutral point O, and the other end is connected with the capacitor C s . Capacitor C s One end is connected with a resistor R s The other end is connected with the ground wire of the circuit system. The common mode interference signal of the circuit system can be sampled by a noise signal sampling circuit, and the noise signal sampling circuit is connected with a resistor R s Which generates an interference voltage related to the common mode interference signal. Resistor R g Resistance R f Sum operational amplifier U 1 A noise signal amplifying circuit is constituted. Resistor R g One end of (a) is connected with resistor R s And capacitor C s The common connection point of the noise signal amplifying circuit is connected with the other end of the operational amplifier U 1 Is provided. Resistor R f Is an operational amplifier U 1 A feedback resistor of (a) and an operational amplifier U 1 Is connected with the reverse input end of the (B) and the other end is connected with the operational amplifier U 1 Is provided. Operational amplifier U 1 Is connected with the neutral point O. Resistor R inj And capacitor C inj Forms noise signal compensation circuit together, resistor R inj One end and an operational amplifier U 1 The other end is connected with a capacitor C inj . Capacitor C inj One end is connected with a resistor R inj The other end is connected with the ground wire of the circuit system. The noise signal compensation circuit is capable of converting a signal processed by the noise signal amplification circuit into a noise compensation signal, and the noise compensation signal is injected into the circuit. The generated noise compensation signal has a relationship of equal amplitude and opposite phase to the original noise signal, so that the noise compensation signal can be counteracted with the original noise signal, and the purpose of noise suppression is achieved.
Referring to fig. 3, a curve Q1 is a common mode interference signal generated by the flyback converter when the common mode active filter with a simplified structure is not yet connected to the circuit. Curve Q2 is the common mode interference signal after adding the common mode active filter with a reduced structure. The amplitude of the common mode interference signal can be obviously reduced by comparing the amplitudes of the common mode interference signals before and after the common mode active filter with the simplified structure is added, and the common mode active filter with the simplified structure has extremely strong inhibition capability on the common mode interference signal.
Claims (7)
1. A common mode active filter having a reduced structure, comprising: the neutral point constructing circuit constructs a neutral point which is used as the reference ground of the noise signal sampling circuit and the noise signal amplifying circuit, the noise signal sampling circuit samples the noise signal through a network composed of a resistor and a capacitor, the noise signal sampling circuit is connected to the noise signal amplifying circuit as an input, the noise signal amplifying circuit processes the sampled noise and then outputs a processed output signal, a terminal of the output signal is connected with the noise signal compensating network, the neutral point constructing circuit constructs a neutral point at the input end of a circuit system, the neutral point constructing circuit is used as the reference ground of the common mode active filter with a simplified structure, and the capacitor C is used as the neutral point constructing circuit 1 And capacitor C 2 Is composed of capacitor C 1 And capacitor C 2 The connection point of the circuit is a neutral point O of the structure, the noise signal sampling circuit samples common mode interference signals between the neutral point and the ground wire of the circuit system, and the noise signal sampling circuit transmits the sampled common mode interference signals to the input end of the noise signal amplifying circuit.
2. The filter of claim 1, wherein the noise signal sampling circuit is configured to sample a common mode interference signal in the circuitry, the noise signal sampling circuit is connected to an input of the noise signal amplifying circuit, and to transmit the sampled common mode interference signal to the noise signal amplifying circuit for signal processing, and the noise signal sampling circuit is configured to sample the noise signalSignal sampling circuit is by electric capacity C s And resistance R s Form, capacitance C s And resistance R s Outputs the sampled common mode interference signal and passes it to the noise signal amplifying circuit section.
3. The common-mode active filter with simplified structure as claimed in claim 1, wherein said noise signal amplifying circuit has its input connected to the noise signal sampling circuit for processing the common-mode interference signal collected by the noise signal sampling circuit to generate an output signal for compensating the common-mode interference signal of the circuit, the output of the noise signal amplifying circuit is connected to the noise signal compensating circuit, and the noise signal amplifying circuit is composed of a resistor R g Resistance R f Sum operational amplifier U 1 Composition, resistance R g One end is connected with a capacitor C s And resistance R s The other end is connected with an operational amplifier U 1 The reverse input terminal of (a), the resistor R f One end is connected with the operational amplifier U 1 The other end is connected with the operational amplifier U 1 The same direction input end of the operational amplifier is connected with the neutral point O constructed by the neutral point construction circuit.
4. The common mode active filter with reduced structure according to claim 1, wherein the noise signal compensation circuit converts an output signal generated by the noise signal amplifying circuit into a compensation signal to be injected into the circuit system for noise suppression, and the noise signal compensation circuit comprises a resistor R inj And capacitor C inj Composition, resistance R inj One end is connected with the operational amplifier U 1 The other end is connected with a capacitor C inj， Capacitor C inj One end is connected with a resistor R inj The other end is connected with the ground wire of the circuit system.
5. The common mode active filter with reduced structure of claim 1, wherein the neutral point configuration circuit is connected to a power supply terminal of the circuitry, the neutral point potential being equal to a midpoint of the power supply terminal potential of the circuitry.
6. The reduced structure common mode active filter of claim 1 wherein the noise signal amplifying circuit is capable of processing the sampled common mode interference signal to produce an output signal having an amplitude and phase related to the original common mode interference signal.
7. The common-mode active filter with a reduced structure according to claim 1, wherein the noise signal compensation circuit is capable of converting an output signal of the noise signal amplification circuit into a corresponding compensation signal, and the final compensation signal is capable of canceling the common-mode interference signal existing in the circuit system in the form of a current or a voltage, thereby achieving the purpose of noise suppression.
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| CN202111510689.9A CN114157134B (en) | 2021-12-10 | 2021-12-10 | Common mode active filter with simplified structure |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202111510689.9A CN114157134B (en) | 2021-12-10 | 2021-12-10 | Common mode active filter with simplified structure |
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| CN114157134A CN114157134A (en) | 2022-03-08 |
| CN114157134B true CN114157134B (en) | 2024-03-29 |
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000201044A (en) * | 1999-01-07 | 2000-07-18 | Mitsubishi Electric Corp | Common mode noise reducing device |
| CN102714469A (en) * | 2010-01-13 | 2012-10-03 | 株式会社东芝 | Grid-tie inverter |
| KR20160123034A (en) * | 2015-04-15 | 2016-10-25 | 강원대학교산학협력단 | Active EMI filter apparatus by coupling common mode filter and differential mode filter |
| JP2017051085A (en) * | 2015-09-01 | 2017-03-09 | 富士電機株式会社 | Active noise suppressing device |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20210313966A1 (en) * | 2020-04-07 | 2021-10-07 | Texas Instruments Incorporated | Active electromagnetic interference (emi) filter for common-mode emi reduction |
-
2021
- 2021-12-10 CN CN202111510689.9A patent/CN114157134B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000201044A (en) * | 1999-01-07 | 2000-07-18 | Mitsubishi Electric Corp | Common mode noise reducing device |
| CN102714469A (en) * | 2010-01-13 | 2012-10-03 | 株式会社东芝 | Grid-tie inverter |
| KR20160123034A (en) * | 2015-04-15 | 2016-10-25 | 강원대학교산학협력단 | Active EMI filter apparatus by coupling common mode filter and differential mode filter |
| JP2017051085A (en) * | 2015-09-01 | 2017-03-09 | 富士電機株式会社 | Active noise suppressing device |
Non-Patent Citations (2)
| Title |
|---|
| DC/DC开关电源有源共模EMI滤波器的研制;郑宪龙;和军平;唐志;;电力电子技术;20071220(第12期);第45-47页 * |
| PWM电机驱动系统中共模电压和轴电压的抑制;肖芳;孙力;孙亚秀;;电机与控制学报;20090515(03);第402-407页 * |
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