CN210807200U - Common mode active EMI filter - Google Patents

Common mode active EMI filter Download PDF

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Publication number
CN210807200U
CN210807200U CN201921101356.9U CN201921101356U CN210807200U CN 210807200 U CN210807200 U CN 210807200U CN 201921101356 U CN201921101356 U CN 201921101356U CN 210807200 U CN210807200 U CN 210807200U
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China
Prior art keywords
module
resistor
unit
capacitor
common mode
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CN201921101356.9U
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Chinese (zh)
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周灵兵
范玲莉
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LG Electronics Shanghai Research and Development Center Co Ltd
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LG Electronics Shanghai Research and Development Center Co Ltd
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Abstract

The utility model discloses an active EMI wave filter of common mode connects electric wire netting and consumer respectively, this active EMI wave filter of common mode includes sampling module, power module, operational amplification module and current injection module, power module provides operating voltage to the operational amplification module, sampling module gathers the common mode EMI electric current that flows to the electric wire netting from the consumer, the operational amplification module is enlargied the common mode EMI electric current and is filtered, the common mode EMI electric current after the current injection module will be enlargied and is filtered is injected into the ground. Compare in the great EMI wave filter of volume in the past, the utility model provides an active EMI wave filter of common mode only needs power module, sampling module, operational amplification module and current injection module, can eliminate the common mode EMI electric current in the circuit, effectively reduces EMI wave filter's volume and cost.

Description

Common mode active EMI filter
Technical Field
The utility model relates to a power electronic technology field especially relates to active EMI wave filter of common mode.
Background
This section is intended to provide a background or context to the embodiments of the invention that are recited in the claims. The description herein is not admitted to be prior art by inclusion in this section.
A standard EMI filter is generally a low-pass filter circuit consisting of a series reactor and a parallel capacitor, which functions to attenuate high-frequency noise signals. That is, the conventional EMI filter is mainly a filter composed of an inductor and a capacitor, and two-stage filtering is usually required when the conventional EMI filter is used, so that the conventional EMI filter has a large volume and a high cost.
Therefore, the conventional EMI filter has the problems of large volume and high cost.
SUMMERY OF THE UTILITY MODEL
The embodiment of the utility model provides an active EMI wave filter of common mode connects electric wire netting and consumer respectively for reduce EMI wave filter's volume and cost, this active EMI wave filter of common mode includes:
the device comprises a sampling module, a power supply module, an operational amplification module and a current injection module;
the first end and the second end of the sampling module are respectively connected with a live wire and a zero wire of a power grid, and the third end and the fourth end of the sampling module are respectively connected with the first end and the second end of electric equipment; the first end and the second end of the power supply module are respectively connected with the first end and the second end of the electric equipment; the fifth end and the sixth end of the sampling module are respectively connected with the first end and the second end of the operational amplification module; the third end and the fourth end of the operational amplification module are respectively connected with the third end of the power supply module and the first end of the current injection module; the second end of the current injection module is respectively connected with the ground wire of the power grid and the ground wire of the electric equipment;
the power supply module is used for supplying working voltage to the operational amplification module; the sampling module is used for collecting common-mode EMI current flowing from the electric equipment to the power grid; the operational amplification module is used for amplifying and filtering the common-mode EMI current; and the current injection module is used for injecting the amplified and filtered common-mode EMI current into the ground.
The embodiment of the utility model provides an in, power module provides operating voltage to the operational amplification module, and sampling module gathers the common mode EMI electric current that flows to the electric wire netting from the consumer, and the operational amplification module is enlargied the common mode EMI electric current and is filtered, and the current injection module will be enlargied and common mode EMI electric current after the filtering and pour into the earth into. Therefore, compare in the great EMI wave filter of volume in the past, the embodiment of the utility model provides an active EMI wave filter of common mode only needs power module, sampling module, operational amplification module and current injection module, can eliminate the common mode EMI electric current in the circuit, effectively reduces EMI wave filter's volume and cost.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts. In the drawings:
fig. 1 is a functional block diagram of a common mode active EMI filter according to an embodiment of the present invention;
fig. 2 is a circuit diagram of a sampling module 10 in a common mode active EMI filter according to an embodiment of the present invention;
fig. 3 is a circuit structure diagram of a first voltage stabilizing unit 201 in a power supply module 20 in a common mode active EMI filter according to an embodiment of the present invention;
fig. 4 is a circuit diagram of a second voltage stabilizing unit 202 in the power supply module 20 in the common mode active EMI filter according to an embodiment of the present invention;
fig. 5 is a block diagram illustrating an operational amplifier module 30 in a common-mode active EMI filter according to an embodiment of the present invention;
fig. 6 is a circuit structure diagram of a differential amplifying unit 301 in an operational amplifying module 30 in a common mode active EMI filter according to an embodiment of the present invention;
fig. 7 is a circuit diagram of a bias unit 302 in the operational amplifier module 30 in the common mode active EMI filter according to an embodiment of the present invention;
fig. 8 is a circuit diagram of a current injection module 40 in a common mode active EMI filter according to an embodiment of the present invention;
fig. 9 is another functional block diagram of a common mode active EMI filter according to an embodiment of the present invention;
fig. 10 is a circuit diagram of an oscillation suppressing module 50 in a common mode active EMI filter according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the embodiments of the present invention are described in further detail below with reference to the accompanying drawings. The exemplary embodiments and descriptions of the present invention are provided to explain the present invention, but not to limit the present invention.
Fig. 1 shows functional modules of a common mode active EMI filter provided by an embodiment of the present invention, and only shows portions related to the embodiment of the present invention for convenience of description, and the detailed description is as follows:
as shown in fig. 1, the common mode active EMI filter is respectively connected to a power grid 1 and a power consumption device 2, and includes:
the device comprises a sampling module 10, a power supply module 20, an operational amplification module 30 and a current injection module 40.
A first end and a second end of the sampling module 10 are respectively connected with a live wire and a zero wire of the power grid 1, and a third end and a fourth end of the sampling module 10 are respectively connected with a first end and a second end of the electric equipment 2; the first end and the second end of the power supply module 20 are respectively connected with the first end and the second end of the electric equipment 2; the fifth end and the sixth end of the sampling module 10 are respectively connected with the first end and the second end of the operational amplification module 30; the third end and the fourth end of the operational amplification module 30 are respectively connected with the third end of the power supply module 20 and the first end of the current injection module 40; the second end of the current injection module 40 is connected to the ground line of the power grid 1 and the ground line of the electric device 2, respectively.
A power supply module 20 for supplying a working voltage to the operational amplification module 30; the sampling module 10 is used for collecting the common-mode EMI current flowing from the electric equipment 2 to the power grid 1; the operational amplification module 30 is used for amplifying and filtering the common-mode EMI current; and a current injection module 40 for injecting the amplified and filtered common mode EMI current to ground.
The electric device 2 may be, for example, an in-vehicle charger, or may be another electric device 2 other than the in-vehicle charger.
The embodiment of the utility model provides an in, power module 20 provides operating voltage to operational amplification module 30, and sampling module 10 gathers the common mode EMI electric current that flows to electric wire netting 1 from consumer 2, and operational amplification module 30 enlargies and filters the common mode EMI electric current, and current injection module 40 will enlarge and common mode EMI electric current after the filtering pours into the earth into. Therefore, compare in the great EMI wave filter of volume in the past, the embodiment of the utility model provides an active EMI wave filter of common mode only needs power module 20, sampling module 10, operational amplification module 30 and current injection module 40, can eliminate the common mode EMI electric current in the circuit, effectively reduces EMI wave filter's volume and cost.
Fig. 2 shows a circuit structure of the sampling module 10 in the common mode active EMI filter provided by the embodiment of the present invention, and only the parts related to the embodiment of the present invention are shown for convenience of description, and detailed descriptions are as follows:
in an embodiment of the present invention, as shown in fig. 2, the sampling module 10 includes:
the first end and the second end of the current transformer T1 and the current transformer T1 are the first end and the second end of the sampling module 10, the third end and the fourth end of the current transformer T1 are the third end and the fourth end of the sampling module 10, and the fifth end and the sixth end of the current transformer T1 are the fifth end and the sixth end of the sampling module 10, respectively.
In the embodiment of the utility model, utilize current transformer T1 can further effectual collection from consumer 2 to the common mode EMI electric current of electric wire netting 1.
Fig. 3 shows a circuit structure of the first voltage stabilizing unit 201 in the power supply module 20 in the common mode active EMI filter provided by the embodiment of the present invention, and for convenience of description, only the parts related to the embodiment of the present invention are shown, and detailed descriptions are as follows:
in an embodiment of the present invention, as shown in fig. 3, the first end, the second end and the third end of the first voltage stabilizing unit 201 are the first end, the second end and the third end of the power supply module 20, respectively, and the first voltage stabilizing unit 201 includes:
the circuit comprises a first rectifier diode D1, a first resistor R1, a second resistor R2, a first triode Q1, a first voltage stabilizing diode D21 and a first capacitor C1;
the anode of the first rectifying diode D1 is the first end of the first voltage stabilizing unit 201, and the cathode of the first rectifying diode D1 is respectively connected to the first end of the first resistor R1 and the first end of the second resistor R2; a second end of the second resistor R2 is connected with a collector of the first triode Q1, and a first end of the first capacitor C1 is connected with an emitter of the first triode Q1; the second end of the first resistor R1, the cathode of the first zener diode D21 and the base of the first transistor Q1 are commonly connected to form the second end of the first voltage stabilization unit 201; the anode of the first zener diode D21 and the second terminal of the first capacitor C1 are commonly connected to form the third terminal of the first zener cell 201.
The embodiment of the present invention provides an embodiment, the first voltage stabilizing unit 201 in the power supply module 20 directly takes the power from the line by ac (can also take the power by dc under other circumstances), therefore, the first end (i.e. the positive pole of the first rectifier diode D1) and the third end (i.e. the positive pole of the first voltage stabilizing diode D21 and the second end of the first capacitor C1 are connected together) of the first voltage stabilizing unit 201 can be exchanged, and the function of providing the operating voltage to the operational amplifier module 30 can still be realized after the exchange.
Due to the existence of the first rectifying diode D1 in the first voltage stabilizing unit 201 in the power supply module 20, the power supply module 20 (or the first voltage stabilizing unit 201 in the embodiment of the present invention) is turned on only in the positive half cycle of the power grid 1, and the negative half cycle is turned off, which is equivalent to the first rectifying diode D1 rectifying and supplying power to the power supply module 20.
Fig. 4 shows a circuit structure of the second voltage stabilizing unit 202 in the power supply module 20 in the common mode active EMI filter provided by the embodiment of the present invention, and for convenience of description, only the parts related to the embodiment of the present invention are shown, and detailed descriptions are as follows:
in an embodiment of the present invention, as shown in fig. 4, the first end and the second end of the second voltage stabilizing unit 202 are respectively connected to the second end and the third end of the first voltage stabilizing unit 201, the third end of the second voltage stabilizing unit 202 is the third end of the power supply module 20, and the second voltage stabilizing unit 202 includes:
a third resistor R3, a second triode Q2, a second voltage regulator diode D22 and a second capacitor C2;
a first end of the third resistor R3 and a collector of the second transistor Q2 are commonly connected to form a first end of the second voltage stabilizing unit 202; the second end of the third resistor R3 and the cathode of the second voltage-stabilizing diode D22 are connected to the base of the second triode Q2; a first end of the second capacitor C2 and the anode of the second zener diode D22 are connected together to form a second end of the second zener cell 202; a first terminal of the second capacitor C2 and an emitter of the second transistor Q2 are commonly connected to form a third terminal of the second voltage regulation unit 202.
In practical application, the primary voltage stabilization is more suitable for the application scenario of dc power taking, and in view of the ac power taking in the present application, the applicant finds that the output voltage after the primary voltage stabilization still has large fluctuation, and in order to solve the voltage fluctuation existing in the output voltage after the primary voltage stabilization, the applicant proposes to add a voltage stabilization unit, i.e., the second voltage stabilization unit 202, on the basis of the primary voltage stabilization, so that the first voltage stabilization unit 201 realizes preliminary voltage stabilization (for example, the voltage of the first capacitor C1 fluctuates between 10 volts and 20 volts), and the second voltage stabilization unit 202 realizes accurate voltage stabilization (for example, the voltage of the second capacitor C2 stabilizes at about 10 volts).
In the embodiment of the present invention, the second voltage stabilizing unit 202 can realize accurate voltage stabilization, and provide stable operating voltage for the operational amplifier module 30.
Fig. 5 shows the structure of the operational amplifier module 30 in the common mode active EMI filter according to an embodiment of the present invention, and for convenience of description, only the portions related to the embodiment of the present invention are shown, and detailed descriptions are as follows:
in an embodiment of the present invention, as shown in fig. 5, the operational amplifier module 30 includes:
a differential amplification unit 301 and a bias unit 302;
the first end and the second end of the differential amplifying unit 301 are the first end and the second end of the operational amplifying module 30, respectively; the third end of the differential amplifying unit 301 is connected with the first end of the biasing unit 302; the fourth end of the differential amplifying unit 301 and the second end of the biasing unit 302 are connected together to form the third end of the operational amplifying module 30; the fifth terminal of the differential amplifying unit 301 is the fourth terminal of the operational amplifying module 30.
In the embodiment of the present invention, the differential amplification unit 301 has a symmetrical structure and a strong anti-interference performance.
Fig. 6 shows a circuit structure of the differential amplifying unit 301 in the operational amplifying module 30 in the common mode active EMI filter according to an embodiment of the present invention, and only shows the parts related to the embodiment of the present invention for convenience of description, and the detailed description is as follows:
in an embodiment of the present invention, as shown in fig. 6, the differential amplifying unit 301 includes:
a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7 and an operational amplifier U1;
a first end of the fourth resistor R4 and a first end of the fifth resistor R5 are respectively a first end and a second end of the differential amplifying unit 301; the second end of the fourth resistor R4 and the first end of the sixth resistor R6 are connected to the inverting input terminal of the operational amplifier U1; the second end of the fifth resistor R5 and the first end of the seventh resistor R7 are connected to the same-direction input end of the operational amplifier U1; the positive power supply terminal of the operational amplifier U1 is the fourth terminal of the differential amplification unit 301; the power supply cathode of the operational amplifier U1 is grounded, and the output terminal of the operational amplifier U1 is the fifth terminal of the differential amplifying unit 301.
The fourth resistor R4 and the sixth resistor R6 form a negative branch of the operational amplifier U1, and the fifth resistor R5 and the seventh resistor R7 form a positive branch of the operational amplifier U1. In an embodiment of the present invention, the fourth resistor R4 has the same resistance as the fifth resistor R5, and the sixth resistor R6 has the same resistance as the seventh resistor R7. The negative branch and the positive branch of the operational amplifier U1 have symmetrical structures and strong anti-interference performance.
Fig. 7 shows a circuit structure of the bias unit 302 in the operational amplifier module 30 in the common mode active EMI filter according to an embodiment of the present invention, and for convenience of description, only the portions related to the embodiment of the present invention are shown, and detailed descriptions are as follows:
in an embodiment of the present invention, as shown in fig. 7, the bias unit 302 includes:
an eighth resistor R8, a ninth resistor R9, a third capacitor C3 and a fourth capacitor C4;
a first end of the eighth resistor R8, a first end of the ninth resistor R9 and a first end of the third capacitor C3 are commonly connected to form a first end of the bias unit 302; the second end of the third capacitor C3 and the second end of the ninth resistor R9 are connected to the first end of the fourth capacitor C4;
a second terminal of the eighth resistor R8 and a second terminal of the fourth capacitor C4 are commonly connected to form a second terminal of the bias unit 302.
The eighth resistor R8 and the ninth resistor R9 have the same resistance value, divide the output voltage Vc of the power supply module 20 into Vc/2, and provide a bias current for the operational amplifier U1, thereby ensuring that the output of the operational amplifier U1 is not saturated when the input signal is within a certain range during steady-state operation. The third capacitor C3 and the fourth capacitor C4 are used for voltage stabilization and filtering.
Fig. 8 illustrates a circuit structure of the current injection module 40 in the common mode active EMI filter according to an embodiment of the present invention, and only the parts related to the embodiment of the present invention are shown for convenience of description, and detailed descriptions are as follows:
in an embodiment of the present invention, as shown in fig. 8, the current injection module 40 includes:
a tenth resistor R10 and a fifth capacitor C5;
a first terminal of the tenth resistor R10 is a first terminal of the current injection module 40; a second terminal of the tenth resistor R10 is connected to a first terminal of the fifth capacitor C5, and a second terminal of the fifth capacitor C5 is a second terminal of the current injection module 40.
In the embodiment of the present invention, the tenth resistor R10 and the fifth capacitor C5 inject the received amplified and filtered common mode EMI current into the ground.
Fig. 9 shows another functional module of the common mode active EMI filter provided by the embodiment of the present invention, and only the parts related to the embodiment of the present invention are shown for convenience of description, and the detailed description is as follows:
in an embodiment of the present invention, as shown in fig. 9, on the basis of the above circuit structure, the common mode active EMI filter further includes: an oscillation suppression module 50.
The first end and the second end of the oscillation suppression module 50 are connected to the second end of the current injection module 40 and the ground of the electric device 2, respectively.
The embodiment of the present invention provides an oscillation suppression module 50, which can suppress oscillation, and when the circuit effect is better, the oscillation suppression module 50 can be short-circuited.
Fig. 10 illustrates a circuit structure of the oscillation suppression module 50 in the common mode active EMI filter according to an embodiment of the present invention, and only the portions related to the embodiment of the present invention are shown for convenience of description, and detailed descriptions are as follows:
in an embodiment of the present invention, as shown in fig. 10, the oscillation suppressing module 50 includes:
the eleventh resistor R11 and the first and second ends of the eleventh resistor R11 are the first and second ends of the oscillation suppressing module 50, respectively.
In an embodiment of the present invention, the first voltage stabilizing unit 202 in the operational amplification module 30 further includes: a sixth capacitance and a seventh capacitance.
The first end and the second end of the sixth capacitor are respectively connected with the first end and the second end of the sixth resistor R6; the first end and the second end of the seventh capacitor are respectively connected with the first end and the second end of the seventh resistor R7.
In the embodiment of the present invention, the capacitance values of the sixth capacitor and the seventh capacitor are the same, and the sixth capacitor and the seventh capacitor are used for filtering.
In an embodiment of the present invention, the second voltage stabilizing unit 202 in the power supply module 20 further includes:
and the anode of the second diode is commonly connected with the first end of the third resistor R3 and the collector of the second triode Q2, and the cathode of the second diode is the first end of the second voltage stabilizing unit 202.
In the embodiment of the present invention, the second diode can play a role of preventing overshoot.
The following combination the embodiment of the utility model provides an active EMI wave filter's of common mode theory of operation, it is right the utility model discloses briefly explain:
referring to fig. 1 to 10, the power supply module 20 takes power from the power grid 1 to charge the first capacitor C1, and the power taking principle is as follows: during the positive half period of the power grid 1, the first rectifier diode D1 is turned on, the first capacitor C1 is charged through the first rectifier diode D1, the first triode Q1, the first zener diode D21, the first resistor R1 and the second resistor R2, during the negative half period of the power grid 1, the first rectifier diode D1 is turned off and is not charged, and during the period, the second capacitor C2 is continuously charged by the electric energy stored in the first capacitor C1. A stable output voltage Vc of the power supply module 20 (i.e. the voltage of the second capacitor C2) is obtained. The output voltage Vc provides voltages for the operational amplifier U1 and the bias unit 302, respectively.
The sampling element current transformer T1 collects a common mode EMI current flowing from the electric device 2 to the grid 1, the differential amplification unit 301 composed of the fourth resistor R4, the fifth resistor R5, the sixth resistor R6, the seventh resistor R7 and the operational amplifier U1 amplifies the common mode EMI current, and the bias unit 302 composed of the eighth resistor R8, the ninth resistor R9, the third capacitor C3 and the fourth capacitor C4 provides a bias current for the operational amplifier U1. The amplified common mode EMI current is injected to the ground through the current injection module 40 including the tenth resistor R10 and the fifth capacitor C5.
To sum up, the embodiment of the utility model provides an in, power module 20 provides operating voltage to operational amplification module 30, and sampling module 10 gathers the common mode EMI electric current that flows to electric wire netting 1 from consumer 2, and operational amplification module 30 enlargies and filters the common mode EMI electric current, and current injection module 40 will enlarge and common mode EMI electric current after the filtration pours into the earth into. Therefore, compare in the great EMI wave filter of volume in the past, the embodiment of the utility model provides an active EMI wave filter of common mode only needs power module 20, sampling module 10, operational amplification module 30 and current injection module 40, can eliminate the common mode EMI electric current in the circuit, effectively reduces EMI wave filter's volume and cost.
The above-mentioned embodiments, further detailed description of the objects, technical solutions and advantages of the present invention, it should be understood that the above-mentioned embodiments are only specific embodiments of the present invention, and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims (10)

1. A common mode active EMI filter, which is respectively connected with a power grid and electric equipment, is characterized by comprising:
the device comprises a sampling module, a power supply module, an operational amplification module and a current injection module;
the first end and the second end of the sampling module are respectively connected with a live wire and a zero wire of a power grid, and the third end and the fourth end of the sampling module are respectively connected with the first end and the second end of electric equipment; the first end and the second end of the power supply module are respectively connected with the first end and the second end of the electric equipment; the fifth end and the sixth end of the sampling module are respectively connected with the first end and the second end of the operational amplification module; the third end and the fourth end of the operational amplification module are respectively connected with the third end of the power supply module and the first end of the current injection module; the second end of the current injection module is respectively connected with the ground wire of the power grid and the ground wire of the electric equipment;
the power supply module is used for supplying working voltage to the operational amplification module; the sampling module is used for collecting common-mode EMI current flowing from the electric equipment to the power grid; the operational amplification module is used for amplifying and filtering the common-mode EMI current; and the current injection module is used for injecting the amplified and filtered common-mode EMI current into the ground.
2. The common mode active EMI filter of claim 1 wherein the sampling module comprises a current transformer.
3. The common mode active EMI filter of claim 1 wherein the power supply module comprises a first voltage regulation unit, the first terminal, the second terminal and the third terminal of the first voltage regulation unit being the first terminal, the second terminal and the third terminal of the power supply module, respectively, the first voltage regulation unit comprising:
the circuit comprises a first rectifier diode, a first resistor, a second resistor, a first triode, a first voltage stabilizing diode and a first capacitor;
the anode of the first rectifying diode is the first end of the first voltage stabilizing unit, and the cathode of the first rectifying diode is respectively connected with the first end of the first resistor and the first end of the second resistor; the second end of the second resistor is connected with the collector of the first triode, and the first end of the first capacitor is connected with the emitter of the first triode; the second end of the first resistor, the cathode of the first voltage stabilizing diode and the base of the first triode are connected together to form the second end of the first voltage stabilizing unit; the anode of the first voltage stabilizing diode and the second end of the first capacitor are connected together to form a third end of the first voltage stabilizing unit.
4. The common mode active EMI filter of claim 3 wherein the power supply module further comprises a second voltage regulation unit, the first terminal and the second terminal of the second voltage regulation unit are connected to the second terminal and the third terminal of the first voltage regulation unit, respectively, the third terminal of the second voltage regulation unit is the third terminal of the power supply module, the second voltage regulation unit comprises:
the third resistor, the second triode, the second voltage stabilizing diode and the second capacitor;
the first end of the third resistor and the collector of the second triode are connected together to form the first end of the second voltage stabilizing unit; the second end of the third resistor and the negative electrode of the second voltage stabilizing diode are connected to the base electrode of the second triode in common; the first end of the second capacitor and the anode of the second voltage stabilizing diode are connected together to form a second end of the second voltage stabilizing unit; the first end of the second capacitor and the emitter of the second triode are connected together to form the third end of the second voltage stabilizing unit.
5. The common mode active EMI filter of claim 1 wherein the operational amplification module comprises:
a differential amplification unit and a bias unit;
the first end and the second end of the differential amplification unit are respectively the first end and the second end of the operational amplification module; the third end of the differential amplification unit is connected with the first end of the bias unit; the fourth end of the differential amplification unit and the second end of the bias unit are connected in common to form a third end of the operational amplification module; and the fifth end of the differential amplification unit is the fourth end of the operational amplification module.
6. The common mode active EMI filter of claim 5 wherein the differential amplification unit comprises:
a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor and an operational amplifier;
the first end of the fourth resistor and the first end of the fifth resistor are respectively the first end and the second end of the differential amplification unit; the second end of the fourth resistor and the first end of the sixth resistor are connected to the inverting input end of the operational amplifier in common; the second end of the fifth resistor and the first end of the seventh resistor are connected to the same-direction input end of the operational amplifier in common; the positive power supply electrode of the operational amplifier is the fourth end of the differential amplification unit; the negative electrode of the power supply of the operational amplifier is grounded, and the output end of the operational amplifier is the fifth end of the differential amplification unit.
7. The common mode active EMI filter of claim 5 wherein the biasing unit comprises:
an eighth resistor, a ninth resistor, a third capacitor and a fourth capacitor;
the first end of the eighth resistor, the first end of the ninth resistor and the first end of the third capacitor are connected in common to form a first end of the bias unit; the second end of the third capacitor and the second end of the ninth resistor are connected to the first end of the fourth capacitor in common;
the second end of the eighth resistor and the second end of the fourth capacitor are connected in common to form a second end of the bias unit.
8. The common mode active EMI filter of claim 1 wherein the current injection module comprises:
a tenth resistor and a fifth capacitor;
the first end of the tenth resistor is the first end of the current injection module; the second end of the tenth resistor is connected with the first end of the fifth capacitor, and the second end of the fifth capacitor is the second end of the current injection module.
9. The common mode active EMI filter of claim 1 further comprising:
an oscillation suppression module;
the first end and the second end of the oscillation suppression module are respectively connected with the second end of the current injection module and the ground wire of the electric equipment.
10. The common mode active EMI filter of claim 9 wherein the oscillation suppression module comprises:
and the first end and the second end of the eleventh resistor are respectively the first end and the second end of the oscillation suppression module.
CN201921101356.9U 2019-07-15 2019-07-15 Common mode active EMI filter Expired - Fee Related CN210807200U (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201921101356.9U CN210807200U (en) 2019-07-15 2019-07-15 Common mode active EMI filter

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201921101356.9U CN210807200U (en) 2019-07-15 2019-07-15 Common mode active EMI filter

Publications (1)

Publication Number Publication Date
CN210807200U true CN210807200U (en) 2020-06-19

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
CN201921101356.9U Expired - Fee Related CN210807200U (en) 2019-07-15 2019-07-15 Common mode active EMI filter

Country Status (1)

Country Link
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