CN114070036A - Common mode interference suppression circuit - Google Patents

Common mode interference suppression circuit Download PDF

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Publication number
CN114070036A
CN114070036A CN202111349614.7A CN202111349614A CN114070036A CN 114070036 A CN114070036 A CN 114070036A CN 202111349614 A CN202111349614 A CN 202111349614A CN 114070036 A CN114070036 A CN 114070036A
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winding
voltage
circuit
totem
output
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CN114070036B (en
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梅进光
付平
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Inventronics Hangzhou Co Ltd
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Inventronics Hangzhou Co Ltd
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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
    • 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
    • H02M1/12—Arrangements for reducing harmonics from ac input or output
    • 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
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
    • H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
    • H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
    • H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
    • H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/33569—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements
    • 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
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
    • Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Filters And Equalizers (AREA)

Abstract

The invention discloses a common-mode interference suppression circuit which comprises a sampling winding, a conversion circuit and a common-mode suppression capacitor, wherein the common-mode interference suppression circuit is used for eliminating the common-mode interference in a switch resonance circuit by sampling a resonance inductor in the switch resonance circuit and the voltage of a primary winding of a transformer, adding the voltage which has the same frequency as the voltage at the midpoint of a switch tube unit but has the opposite phase to the voltage to the common-mode suppression capacitor and offsetting a common-mode interference signal. In conclusion, the application can eliminate the common mode interference signal in the switch resonant circuit without arranging a large inductor or capacitor in the switch resonant circuit, the excessive size of the switch resonant circuit cannot be increased, and the cost is saved.

Description

Common mode interference suppression circuit
Technical Field
The invention relates to the field of interference suppression, in particular to a common-mode interference suppression circuit.
Background
With the development of technology, a high frequency switching resonant circuit becomes one of the trends of the development of the switching resonant circuit. However, due to the increase of the switching frequency in the switching resonant circuit, EMI (Electromagnetic Interference) becomes one of the problems to be solved by the developers. When a "moving point" with high voltage change frequency exists on a Printed Circuit Board (PCB) in the switch resonant Circuit, a parasitic capacitance exists between the "moving point" and a ground line, and a high-frequency voltage on the "moving point" is applied to the parasitic capacitance, so that strong electromagnetic interference, namely common-mode interference, is formed, and the common-mode interference can pollute a power grid and affect other electronic devices in the same power grid.
Disclosure of Invention
The invention aims to provide a common mode interference suppression circuit, which can eliminate common mode interference signals in a switch resonant circuit without arranging a large inductor or capacitor in the switch resonant circuit, does not increase the excessive volume of the switch resonant circuit, and saves the cost.
In order to solve the technical problem, the application provides a common mode interference suppression circuit, which is characterized in that the common mode interference suppression circuit is applied to a switch resonance circuit, and the switch resonance circuit comprises a switch tube unit, a resonance unit and a transformer which are sequentially connected;
the switch tube unit comprises two switch tubes which are connected in series, and the connection point between the two switch tubes is a midpoint; the resonance unit comprises a resonance capacitor and a resonance inductor;
the common mode interference rejection circuit includes:
the sampling winding is coupled with the resonant inductor and the primary winding of the transformer and is used for outputting voltage with the same frequency as the voltage of the midpoint;
the conversion circuit is connected with the input end of the sampling winding and used for filtering the voltage output by the sampling winding to obtain a common mode rejection signal, the voltage frequency of the common mode rejection signal is the same as the voltage frequency of the midpoint, and the voltage phase is opposite to the voltage phase of the midpoint;
and the common-mode rejection capacitor is connected with the output end of the conversion circuit and is used for cancelling a common-mode interference signal in the switch resonant circuit based on the common-mode rejection signal.
Preferably, the sampling winding includes:
a first winding coupled to the resonant inductor and a second winding coupled to a primary winding of the transformer;
the first end of the first winding is the output end of the sampling winding, the second end of the first winding is connected with the first end of the second winding, and the second end of the second winding is grounded; the first end of the first winding is the end with the same name as one end of the resonant inductor, and forward current of the resonant cavity flows into the resonant inductor; the first end of the second winding is the end with the same name as one end of the primary winding of the transformer, and forward current of the resonant cavity flows into the transformer;
the first winding is used for sampling the voltage on the resonant inductor, and the second winding is used for sampling the voltage of the primary winding of the transformer so as to output the voltage with the same frequency and the same voltage phase as the voltage of the midpoint;
the conversion circuit is specifically configured to filter voltages, which are output by the sampling winding and have the same frequency as the voltage of the midpoint and the same voltage phase, so as to obtain the common mode rejection signal.
Preferably, the conversion circuit comprises a phase reversal triode, a first direct current power supply and a totem-pole circuit;
the control end of the phase reversal triode is connected with the first end of the first winding, the first end of the phase reversal triode is connected with the first direct current power supply, and the second end of the phase reversal triode is grounded;
the phase inversion triode is used for conducting when the voltage output by the sampling winding is larger than a preset voltage, so as to filter the voltage which is output by the sampling winding and has the same frequency as the voltage of the midpoint and has the same voltage phase, and pull down the level of the first end of the phase inversion triode to be a low level;
the first end of the totem-pole circuit is connected with the first direct-current power supply, the second end of the totem-pole circuit is grounded, the control end of the totem-pole circuit is connected with the first end of the phase reversal triode, and the output end of the totem-pole circuit is the output end of the conversion circuit and used for outputting the common mode rejection signal based on the level of the first end of the phase reversal triode.
Preferably, the conversion circuit comprises a phase reversal MOS tube, a second direct current power supply and a totem-pole circuit;
the control end of the phase reversal MOS tube is connected with the first end of the first winding, the first end of the phase reversal MOS tube is connected with the second direct-current power supply, and the second end of the phase reversal MOS tube is grounded;
the phase inversion MOS tube is used for conducting when the voltage output by the sampling winding is greater than a preset voltage, so as to filter the voltage which is output by the sampling winding and has the same frequency as the voltage of the midpoint and has the same voltage phase, and pull down the level of the first end of the phase inversion MOS tube to be a low level;
the first end of the totem-pole circuit is connected with the second direct-current power supply, the second end of the totem-pole circuit is the output end of the conversion circuit, and the control end of the totem-pole circuit is connected with the first end of the phase reversal MOS tube and used for outputting the common mode rejection signal based on the level of the first end of the phase reversal MOS tube.
Preferably, the resonance unit includes a resonance inductance;
the sampling winding includes:
a third winding coupled to the resonant inductor and a fourth winding coupled to a primary winding of the transformer;
the second end of the third winding is the output end of the sampling winding, the first end of the third winding is connected with the second end of the fourth winding, and the first end of the fourth winding is grounded; the first end of the third winding is the end with the same name as one end of the resonant inductor, and forward current of the resonant cavity flows into the resonant inductor; the first end of the fourth winding is the end with the same name as one end of the primary winding of the transformer, wherein the forward current of the resonant cavity flows into the transformer;
the third winding is used for sampling the voltage on the resonant inductor, and the fourth winding is used for sampling the voltage of the primary winding of the transformer so as to output the voltage with the same frequency as the voltage of the midpoint and opposite voltage phase;
the conversion circuit is specifically configured to filter voltages that are output by the sampling winding and have the same frequency as the voltage at the midpoint and have opposite voltage phases, and output the common mode rejection signal.
Preferably, the conversion circuit comprises a filter capacitor, a third direct current power supply and a totem-pole circuit;
the first end of the filter capacitor is connected with the first end of the third winding, and the second end of the filter capacitor is grounded and used for filtering the voltage which is output by the sampling winding, has the same frequency as the voltage of the midpoint and has the same voltage phase;
the first end of the totem-pole circuit is connected with the third direct-current power supply, the second end of the totem-pole circuit is grounded, the control end of the totem-pole circuit is connected with the first end of the filter capacitor, and the output end of the totem-pole circuit is the output end of the conversion circuit and is used for outputting the common mode rejection signal based on the level of the first end of the filter capacitor.
Preferably, the totem-pole circuit comprises an NPN-type triode and a PNP-type triode;
the collector of the NPN type triode is the first end of the totem-pole circuit, and the emitter of the NPN type triode is connected with the emitter of the PNP triode; the collector of the PNP type triode is the second end of the totem-pole circuit; the base electrode of the NPN type triode is connected with the base electrode of the PNP type triode and is a control end of the totem-pole circuit; and the emitting electrode of the NPN type triode and the emitting electrode of the PNP type triode are connected and are output ends of the totem-pole circuit.
Preferably, the totem-pole circuit comprises a PMOS transistor and a diode;
the drain electrode of the PMOS tube is the first end of the totem-pole circuit, the source electrode of the PMOS tube is connected with the anode of the diode and is the output end of the conversion circuit, and the grid electrode of the PMOS tube is connected with the cathode of the diode and is the control end of the totem-pole circuit.
Preferably, the sampling circuit further comprises a rectifying diode arranged between the sampling winding and the converting circuit, and the rectifying diode is used for performing unidirectional rectification on the voltage output by the sampling winding.
Preferably, the resonant inductor and the transformer are integrated magnetic devices, and leakage inductance of a primary winding and a secondary winding of the transformer is the resonant inductor; the sampling winding is a winding coupled with a primary winding of the transformer.
Preferably, the switched resonant circuit is a symmetric half-bridge resonant circuit or an asymmetric half-bridge resonant circuit.
Preferably, the circuit further comprises a resistor disposed between the conversion circuit and the common mode rejection capacitor.
The application provides a common mode interference suppression circuit, which comprises a sampling winding, a conversion circuit and a common mode suppression capacitor, wherein the common mode suppression capacitor is added with a voltage which has the same frequency as the voltage at the midpoint of a switch tube unit but has an opposite phase by sampling the voltage of a resonant inductor in a switch resonant circuit and the voltage of a primary winding of a transformer, and the common mode suppression capacitor is offset with a common mode interference signal so as to eliminate the common mode interference in the switch resonant circuit. In conclusion, the application can eliminate the common mode interference signal in the switch resonant circuit without arranging a large inductor or capacitor in the switch resonant circuit, the excessive size of the switch resonant circuit cannot be increased, and the cost is saved.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed in the prior art and the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.
Fig. 1 is a schematic structural diagram of a common mode interference rejection circuit according to the present invention;
fig. 2 is a schematic structural diagram of a common mode interference rejection circuit according to the present invention;
FIG. 3 is a schematic structural diagram of a first conversion circuit according to the present invention;
FIG. 4 is a schematic structural diagram of a second conversion circuit provided in the present invention;
FIG. 5 is a schematic diagram of another structure of the common mode interference rejection circuit according to the present invention;
FIG. 6 is a schematic structural diagram of a third conversion circuit provided in the present invention;
FIG. 7 is a schematic diagram of an output DC signal according to the present invention;
fig. 8 is a schematic structural diagram of a common mode interference suppression circuit when the switching tube unit provided by the present invention is a symmetric half-bridge resonant circuit;
fig. 9 is a schematic diagram of a signal delay according to the present invention.
Detailed Description
The core of the invention is to provide a common mode interference suppression circuit, which can eliminate the common mode interference signal in the switch resonance circuit without arranging larger inductor or capacitor in the switch resonance circuit, can not increase the excessive volume of the switch resonance circuit, and saves the cost.
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Referring to fig. 1, fig. 1 is a schematic structural diagram of a common mode interference suppression circuit according to the present invention, the circuit is applied to a switching resonant circuit 1, and the switching resonant circuit 1 includes a switching tube unit, a resonant unit and a transformer T, which are connected in sequence;
the switch tube unit comprises two switch tubes which are connected in series, and the connection point between the two switch tubes is a midpoint; the resonance unit comprises a resonance capacitor and a resonance inductor;
the common mode interference rejection circuit includes:
the sampling winding 2 is coupled with the resonant inductor and a primary winding of the transformer T and is used for outputting voltage with the same voltage frequency as the midpoint;
the conversion circuit 3 is connected with the input end of the sampling winding 2 and used for filtering the voltage output by the sampling winding 2 to obtain a common mode rejection signal, the voltage frequency of the common mode rejection signal is the same as the voltage frequency of the midpoint, and the voltage phase is opposite to the voltage phase of the midpoint;
and a common mode rejection capacitor C1 connected to the output terminal of the conversion circuit 3, for canceling the common mode interference signal in the switching resonant circuit 1 based on the common mode rejection signal.
In the present embodiment, the applicant considers that there is generally a large common mode interference in the switching resonant circuit 1, and in order to eliminate the common mode interference in the prior art, a large inductor or capacitor is generally arranged at the input end of the switching resonant circuit 1 to reduce the common mode interference in the switching resonant circuit 1, but the large inductor or capacitor arranged at the input end of the switching resonant circuit 1 has a large volume, which results in an increase in the volume of the driving power supply, and the small volume is a development trend of the driving power supply.
In order to solve the problems in the prior art, the sampling winding 2 is provided in the present application, the sampling winding 2 can sample a voltage having the same frequency as the voltage at the midpoint, then the voltage output by the sampling winding 2 is filtered by the conversion circuit 3, the voltage having the same frequency as the voltage at the midpoint is output after the ac component in the dc output by the sampling winding 2 is filtered, the voltage having the opposite phase to the voltage at the midpoint is output, the voltage having the same frequency as the voltage at the midpoint and having the opposite phase to the voltage at the midpoint is input to the common mode rejection capacitor C1, and the voltage at the common mode rejection capacitor C1 can cancel the common mode interference signal in the switching resonant circuit 1 because the voltage at the common mode rejection capacitor C1 has the opposite phase to the voltage at the midpoint.
It should be noted that, in the present application, only the common mode interference signal in the switching resonant circuit 1 needs to be cancelled, and a large capacitor does not need to be provided.
In conclusion, the application can eliminate the common-mode interference signal in the switch resonant circuit 1 without arranging a large inductor or capacitor in the switch resonant circuit 1, the excessive size of the switch resonant circuit 1 cannot be increased, and the cost is saved.
On the basis of the above-described embodiment:
referring to fig. 2, fig. 2 is a schematic structural diagram of a common mode interference rejection circuit according to the present invention.
As a preferred embodiment, the sampling winding 2 comprises:
a first winding L1 coupled to the resonant inductor L and a second winding L2 coupled to the primary winding of the transformer T;
the first end of the first winding L1 is the output end of the sampling winding 2, the second end is connected with the first end of the second winding L2, and the second end of the second winding L2 is grounded; the first end of the first winding L1 is the end with the same name as one end of the resonant inductor L, and the resonant cavity forward current flows into the resonant inductor L; the first end of the second winding L2 is the end with the same name as one end of the primary winding of the transformer T where the forward current of the resonant cavity flows;
the first winding L1 is used for sampling the voltage on the resonant inductor L, and the second winding L2 is used for sampling the voltage of the primary winding of the transformer T so as to output the voltage with the same frequency and the same voltage phase as the voltage of the midpoint;
the conversion circuit 3 is specifically configured to filter voltages with the same voltage frequency and the same voltage phase and output by the sampling winding 2, so as to obtain a common mode rejection signal, where the voltage frequency of the common mode rejection signal is the same as the voltage frequency of the midpoint, and the voltage phases are opposite to the voltage phase of the midpoint.
The resonant unit in this embodiment includes a resonant inductor L and a resonant capacitor C to form an LC resonant unit, however, the sampling winding 2 in this embodiment only samples the resonant inductor L and the voltage of the primary winding of the transformer T, and since the first winding L1 and the end of the resonant inductor L in this embodiment are on the same side, the second winding L2 and the end of the primary winding of the transformer T are on the same side, and the phases of the voltages output by the first winding L1 and the second winding L2 are the same as the phase of the midpoint voltage, based on this, the converting circuit 3 needs to invert the phase of the voltage output by the sampling winding 2 to output a direct current with the opposite phase to the midpoint phase while filtering the voltage output by the sampling winding 2, that is, when the voltage of the midpoint is greater than zero, the direct current output by the converting circuit 3, that is, the level of the common mode rejection signal is a low level, and when the voltage of the midpoint is less than zero, the level of the common mode rejection signal is high.
In addition, when the resonant inductor L and the transformer T are non-magnetic integrated magnetic devices, that is, the resonant inductor L and the transformer T are independent magnetic devices, the specific structure of the sampling winding 2 is as described above, but when the resonant inductor L and the transformer T are integrated magnetic devices, that is, leakage inductance of the primary winding and the secondary winding of the transformer T is used as the resonant inductor L, the sampling winding 2 is a winding coupled to the primary side of the transformer T.
The midpoint is indicated as point a in fig. 2.
In addition, the first end of the first winding L1 and the first end of the resonant inductor L are on the same side and are homonymous ends; the first end of the second winding L2 and the first end of the primary winding of the transformer T are on the same side and are homonymous ends; the second end of the resonant inductor L is connected with the first end of the primary winding of the transformer T; the second end of the first winding L1 is connected with the first end of the first winding L1; the first end of the first winding L1 is connected to the switching circuit 3, and the second end of the second winding L2 is grounded.
It should be noted that the forward current in this application is the direction of current flowing into the resonant cavity from the bus bar, i.e. the non-grounded end of the switch tube unit.
As a preferred embodiment, the conversion circuit 3 includes a phase inversion transistor a1, a first dc power supply Vcc1, and a totem pole circuit;
the control end of the phase reversal triode A1 is connected with the first end of the first winding L1, the first end is connected with the first direct current power supply Vcc1, and the second end is grounded;
the phase inversion triode A1 is used for conducting when the voltage output by the sampling winding 2 is greater than the preset voltage, so as to filter the voltage with the same frequency and the same voltage phase at the middle point output by the sampling winding 2 and pull down the level of the first end of the phase inversion triode A1 to be a low level;
the totem-pole circuit has a first end connected to the first dc power supply Vcc1, a second end grounded, a control end connected to the first end of the phase inversion triode a1, and an output end of the switching circuit 3, for outputting a common mode rejection signal based on the level of the first end of the phase inversion triode a 1.
Referring to fig. 3, fig. 3 is a schematic structural diagram of a first conversion circuit provided in the present invention.
In the embodiment, a specific structure of the conversion circuit 3 is given, and when the phase of the voltage output by the sampling winding 2 is the same as the phase of the midpoint, the conversion circuit 3 needs to invert the phase, that is, the phase of the voltage output by the sampling winding 2 is 180 ° different from the phase of the midpoint, so that the conversion circuit 3 is provided with a phase inversion triode a1, a first direct-current power supply Vcc1 and a totem-pole circuit.
When the voltage output by the sampling winding 2 is greater than the preset voltage, the phase inversion triode a1 is turned on, the level of the first end of the phase inversion triode a1 is pulled down, and the level of the output end in the totem-pole circuit is pulled down, so that a low level is output; when the voltage output by the sampling winding 2 is not greater than the preset voltage, the phase inversion triode a1 is turned off, the first end of the phase inversion triode a1 is pulled high by the first direct-current power supply Vcc1, and the level of the output end of the totem-pole circuit is also pulled high.
As a preferred embodiment, the conversion circuit 3 includes a Metal-Oxide-Semiconductor Field-Effect Transistor (MOS) Transistor a4, a second dc power supply Vcc2, and a totem-pole circuit;
the control end of the phase reversal MOS tube A4 is connected with the first end of the first winding L1, the first end is connected with the second direct current power supply Vcc2, and the second end is grounded;
the phase inversion MOS tube A4 is used for conducting when the voltage output by the sampling winding 2 is greater than a preset voltage, so as to filter the voltage with the same frequency and the same voltage phase at the middle point output by the sampling winding 2, and pull down the level of the first end of the phase inversion MOS tube A to a low level;
the totem-pole circuit has a first terminal connected to the second dc power Vcc2, a second terminal serving as an output terminal of the switching circuit 3, and a control terminal connected to the first terminal of the phase inversion MOS transistor a4, and is configured to output the common mode rejection signal based on the level of the first terminal of the phase inversion MOS transistor a 4.
Referring to fig. 4, fig. 4 is a schematic structural diagram of a second conversion circuit provided in the present invention.
In the present embodiment, another specific structure of the converting circuit 3 is provided, when the phase of the voltage output by the sampling winding 2 is the same as the phase of the midpoint, the converting circuit 3 needs to invert the phase, that is, the phase of the voltage output by the sampling winding 2 is 180 ° different from the phase of the midpoint, so that the converting circuit 3 is provided with a phase inversion MOS transistor a4, a second dc power supply Vcc2, and a totem-pole circuit.
When the voltage output by the sampling winding 2 is greater than the preset voltage, the phase inversion MOS tube A4 is switched on, the level of the first end of the phase inversion MOS tube A4 is pulled down, the level of the output end in the totem-pole circuit is pulled down, and therefore a low level is output; when the voltage output by the sampling winding 2 is not greater than the preset voltage, the second rectifier diode D2 is turned off, the phase inversion MOS transistor a4 is turned off, the first end of the phase inversion MOS transistor a4 is pulled high by the second direct-current power supply Vcc2, and the level of the output end of the totem-pole circuit is also pulled high.
As a preferred embodiment, the resonance unit includes a resonance inductance L;
the sampling winding 2 includes:
a third winding L3 coupled to the resonant inductor L and a fourth winding L4 coupled to the primary winding of the transformer T;
the second end of the third winding L3 is the output end of the sampling winding 2, the first end is connected with the second end of the fourth winding L4, and the first end of the fourth winding L4 is grounded; the first end of the third winding L3 is the end with the same name as one end of the resonant inductor L, and the forward current of the resonant cavity flows into the resonant inductor L; the first end of the fourth winding L4 is the end with the same name as one end of the primary winding of the transformer T where the forward current of the resonant cavity flows;
the third winding L3 is used for sampling the voltage on the resonant inductor L, and the fourth winding L4 is used for sampling the voltage of the primary winding of the transformer T so as to output the voltage with the same frequency as the voltage of the midpoint and the opposite voltage phase;
the conversion circuit 3 is specifically configured to filter the voltages with the same frequency and opposite voltage phases at the midpoint output by the sampling winding 2, and output a common mode rejection signal.
Referring to fig. 5, fig. 5 is another structural schematic diagram of the common mode interference suppression circuit provided by the present invention, in this embodiment, the third winding L3 and the end with the same name of the resonant inductor L are not on the same side, and the fourth winding L4 and the end with the same name of the primary winding of the transformer T are not on the same side, so that the phases of the voltages output by the third winding L3 and the fourth winding L4 and the phase of the midpoint are opposite, based on which, the conversion circuit 3 can output the direct current with the phases opposite to the midpoint without inverting the voltage while rectifying the voltage output by the sampling winding 2, that is, the direct current output by the conversion circuit 3, that is, the level of the common mode suppression signal is low level when the voltage of the midpoint is greater than zero, and the level of the common mode suppression signal is high level when the voltage of the midpoint is less than zero.
It should be noted that the second end of the third winding L3 and the first end of the resonant inductor L are on the same side and are homonymous ends; the second end of the fourth winding L4 and the first end of the primary winding of the transformer T are on the same side and are homonymous ends; the second end of the resonant inductor L is connected with the first end of the primary winding of the transformer T; the second end of the third winding L3 is connected with the first end of the third winding L3; the first end of the third winding L3 is connected to the switching circuit 3, and the second end of the fourth winding L4 is grounded.
As a preferred embodiment, the conversion circuit 3 includes a filter capacitor C0, a third dc power supply Vcc3, and a totem-pole circuit;
the first end of the filter capacitor C0 is connected with the first end of the third winding L3, the second end of the filter capacitor C0 is grounded and is used for filtering the voltages with the same frequency and the same voltage phase at the middle point output by the sampling winding 2;
the totem-pole circuit has a first end connected to the third dc power Vcc3, a second end grounded, a control end connected to the first end of the filter capacitor C0, and an output end of the conversion circuit 3, and is configured to output the common mode rejection signal based on the level of the first end of the filter capacitor C0.
Referring to fig. 6, fig. 6 is a schematic structural diagram of a third conversion circuit provided in the present invention.
In the embodiment, a specific structure that the phase of the voltage output by the conversion circuit 3 in the sampling winding 2 is opposite to the phase of the voltage of the middle point of the switching tube unit is given, when the phase of the voltage output by the sampling winding 2 is opposite to the phase of the middle point, the conversion circuit 3 only needs to rectify the voltage without inversion, and therefore, the filter capacitor C0, the third direct-current power supply Vcc3 and the totem-pole circuit are arranged in the conversion circuit 3.
When the level of the first end of the filter capacitor C0 is low, the level of the output end in the totem-pole circuit is pulled low, so as to output a low level; when the level of the first end of the filter capacitor C0 is high, the level of the output end of the totem-pole circuit is also pulled high, so that the phase of the voltage output by the totem-pole circuit is opposite to that of the voltage at the midpoint, and a common mode rejection signal is output.
As a preferred embodiment, the totem pole circuit includes an NPN (Negative-Positive-Negative) type transistor a2 and a PNP (Positive-Negative-Positive) type transistor A3;
the collector of the NPN type triode A2 is the first end of the totem pole circuit, and the emitter is connected with the emitter of the PNP triode; the collector of the PNP type triode A3 is the second end of the totem-pole circuit; the base electrode of the NPN type triode A2 is connected with the base electrode of the PNP type triode A3 and is the control end of the totem pole circuit; the emitter of the NPN type triode A2 is connected with the emitter of the PNP type triode A3 and is the output end of the totem pole circuit.
As shown in fig. 3, the totem pole circuit in this embodiment includes an NPN transistor a2 and a PNP transistor A3, where the NPN transistor a2 is turned on at a high level, the PNP transistor A3 is turned on at a low level, bases of the NPN transistor a2 and the PNP transistor A3 are connected together, and are connected to a first end of the phase inversion transistor a1 or the phase inversion MOS transistor a4, when a first end of the phase inversion transistor a1 or the phase inversion MOS transistor a4 or a first end of the filter capacitor C0 is at a high level, the PNP transistor A3 is turned off, the NPN transistor a2 is turned on, and the totem pole circuit outputs a high level; when the first end of the phase reversal triode a1 or the phase reversal MOS transistor a4 or the first end of the filter capacitor C0 is at a low level, the PNP triode A3 is turned on, the NPN triode a2 is turned off, and the totem-pole circuit outputs a low level.
The totem-pole circuit converts the square wave voltage into a large current, so that the common mode can be driven to realize rapid charging and discharging of the common mode rejection capacitor C1.
As a preferred embodiment, the totem-pole circuit comprises a PMOS transistor a5 and a diode D;
the drain of the PMOS transistor a5 is the first end of the totem-pole circuit, the source is connected to the anode of the diode D and is the output end of the conversion circuit 3, and the gate is connected to the cathode of the diode D and is the control end of the totem-pole circuit.
As shown in fig. 4, the totem-pole circuit in this embodiment includes a PMOS transistor a5 and a diode D, when the first terminal of the phase-reversing transistor a1 or the phase-reversing MOS transistor a4 or the first terminal of the filter capacitor C0 is at a low level, the source of the PMOS transistor a5 is at a low level, and when the first terminal of the phase-reversing transistor a1 or the phase-reversing MOS transistor a4 or the first terminal of the filter capacitor C0 is at a high level, the source of the PMOS transistor a5 is at a high level, so as to output the common mode rejection signal and rapidly charge and discharge the common mode rejection capacitor C1.
As a preferred embodiment, a rectifier diode is further included between the sampling winding 2 and the switching circuit 3, and is used for performing unidirectional rectification on the voltage output by the sampling winding 2.
In consideration of the fact that the voltage output by the sampling winding 2 may have a negative value, the switching circuit in the application is provided with a switching tube, the voltage resistance of the switching tube is limited, and the switching tube is prevented from being broken down.
Specifically, refer to the first rectifying diode D1 in fig. 3, the second rectifying diode D2 in fig. 4, and the third rectifying diode D3 in fig. 6.
Referring to fig. 7, fig. 7 is a schematic diagram of an output dc signal according to the present invention, in which V1 is a voltage signal output after rectification by a rectifier diode, and V2 is a voltage signal output after further filtering by a phase inversion MOS transistor a4, a phase inversion transistor a1, or a filter capacitor C0 in a conversion circuit.
In a preferred embodiment, the switching tube unit is a symmetrical half-bridge resonant circuit or an asymmetrical half-bridge resonant circuit.
Referring to fig. 8, fig. 8 is a schematic structural diagram of a common mode interference suppression circuit when the switching tube unit provided by the present invention is a symmetric half-bridge resonant circuit.
In this embodiment, it is given that the switch tube unit may be a symmetric half-bridge resonant circuit or an asymmetric half-bridge resonant circuit, where the symmetric half-bridge resonant circuit includes two switch tubes and two capacitors, the two switch tubes are connected in series, the two capacitors are connected in series, and the two switch tubes connected in series and the two capacitors connected in series are connected in parallel, as shown in fig. 7, a common end of the two switch tubes connected in series is a midpoint.
The asymmetric half-bridge resonant circuit comprises two switching tubes which are connected in series to form a bridge arm, and similarly, the common point of the two switching tubes which are connected in series is a midpoint.
Of course, the common mode interference suppression circuit in the present application is not limited to be applied to a symmetric half-bridge resonant circuit or an asymmetric half-bridge resonant circuit, and may also be applied to other switching resonant circuits 1 to suppress common mode interference only, and therefore, the present application is not limited thereto.
As a preferred embodiment, a resistor R0 is further included between the conversion circuit 3 and the common mode rejection capacitor C1.
Considering that the switching tube or the MOS tube is disposed in the conversion circuit 3, and therefore a certain delay exists between the common mode rejection signal output by the conversion circuit 3 and the voltage at the midpoint of the switching tube unit, please refer to fig. 9, where fig. 9 is a schematic diagram of a signal delay provided by the present invention, so that there is delay interference when charging the common mode rejection capacitor C1, that is, a large current oscillation is generated on the common mode rejection capacitor C1, which results in a reduction in the common mode rejection effect, therefore, a resistor R0 is further disposed in the present application to reduce the oscillation, so as to suppress the delay when the conversion circuit 3 outputs the common mode rejection signal, and ensure the effectiveness of the common mode rejection circuit.
In fig. 9, Va is a voltage obtained by rectifying a midpoint voltage, and Vout is an output voltage of the converter circuit 3.
It is further noted that, in the present specification, relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (12)

1. The common-mode interference suppression circuit is characterized by being applied to a switch resonance circuit, wherein the switch resonance circuit comprises a switch tube unit, a resonance unit and a transformer which are sequentially connected;
the switch tube unit comprises two switch tubes which are connected in series, and the connection point between the two switch tubes is a midpoint; the resonance unit comprises a resonance capacitor and a resonance inductor;
the common mode interference rejection circuit includes:
the sampling winding is coupled with the resonant inductor and the primary winding of the transformer and is used for outputting voltage with the same frequency as the voltage of the midpoint;
the conversion circuit is connected with the input end of the sampling winding and used for filtering the voltage output by the sampling winding to obtain a common mode rejection signal, the voltage frequency of the common mode rejection signal is the same as the voltage frequency of the midpoint, and the voltage phase is opposite to the voltage phase of the midpoint;
and the common-mode rejection capacitor is connected with the output end of the conversion circuit and is used for cancelling a common-mode interference signal in the switch resonant circuit based on the common-mode rejection signal.
2. The common mode interference rejection circuit as in claim 1 wherein said sampling winding comprises:
a first winding coupled to the resonant inductor and a second winding coupled to a primary winding of the transformer;
the first end of the first winding is the output end of the sampling winding, the second end of the first winding is connected with the first end of the second winding, and the second end of the second winding is grounded; the first end of the first winding is the end with the same name as one end of the resonant inductor, and forward current of the resonant cavity flows into the resonant inductor; the first end of the second winding is the end with the same name as one end of the primary winding of the transformer, and forward current of the resonant cavity flows into the transformer;
the first winding is used for sampling the voltage on the resonant inductor, and the second winding is used for sampling the voltage of the primary winding of the transformer so as to output the voltage with the same frequency and the same voltage phase as the voltage of the midpoint;
the conversion circuit is specifically configured to filter voltages, which are output by the sampling winding and have the same frequency as the voltage of the midpoint and the same voltage phase, so as to obtain the common mode rejection signal.
3. The common mode interference rejection circuit of claim 2 wherein said conversion circuit comprises a phase inversion transistor, a first direct current power supply, and a totem-pole circuit;
the control end of the phase reversal triode is connected with the first end of the first winding, the first end of the phase reversal triode is connected with the first direct current power supply, and the second end of the phase reversal triode is grounded;
the phase inversion triode is used for conducting when the voltage output by the sampling winding is larger than a preset voltage, so as to filter the voltage which is output by the sampling winding and has the same frequency as the voltage of the midpoint and has the same voltage phase, and pull down the level of the first end of the phase inversion triode to be a low level;
the first end of the totem-pole circuit is connected with the first direct-current power supply, the second end of the totem-pole circuit is grounded, the control end of the totem-pole circuit is connected with the first end of the phase reversal triode, and the output end of the totem-pole circuit is the output end of the conversion circuit and used for outputting the common mode rejection signal based on the level of the first end of the phase reversal triode.
4. The common mode interference rejection circuit of claim 2 wherein said conversion circuit comprises a phase-inverting MOS transistor, a second dc power supply, and a totem-pole circuit;
the control end of the phase reversal MOS tube is connected with the first end of the first winding, the first end of the phase reversal MOS tube is connected with the second direct-current power supply, and the second end of the phase reversal MOS tube is grounded;
the phase inversion MOS tube is used for conducting when the voltage output by the sampling winding is greater than a preset voltage, so as to filter the voltage which is output by the sampling winding and has the same frequency as the voltage of the midpoint and has the same voltage phase, and pull down the level of the first end of the phase inversion MOS tube to be a low level;
the first end of the totem-pole circuit is connected with the second direct-current power supply, the second end of the totem-pole circuit is the output end of the conversion circuit, and the control end of the totem-pole circuit is connected with the first end of the phase reversal MOS tube and used for outputting the common mode rejection signal based on the level of the first end of the phase reversal MOS tube.
5. The common mode interference rejection circuit as in claim 1 wherein said resonating unit comprises a resonating inductance;
the sampling winding includes:
a third winding coupled to the resonant inductor and a fourth winding coupled to a primary winding of the transformer;
the second end of the third winding is the output end of the sampling winding, the first end of the third winding is connected with the second end of the fourth winding, and the first end of the fourth winding is grounded; the first end of the third winding is the end with the same name as one end of the resonant inductor, and forward current of the resonant cavity flows into the resonant inductor; the first end of the fourth winding is the end with the same name as one end of the primary winding of the transformer, wherein the forward current of the resonant cavity flows into the transformer;
the third winding is used for sampling the voltage on the resonant inductor, and the fourth winding is used for sampling the voltage of the primary winding of the transformer so as to output the voltage with the same frequency as the voltage of the midpoint and opposite voltage phase;
the conversion circuit is specifically configured to filter voltages that are output by the sampling winding and have the same frequency as the voltage at the midpoint and have opposite voltage phases, and output the common mode rejection signal.
6. The common mode interference rejection circuit of claim 5 wherein said conversion circuit comprises a filter capacitor, a third DC power supply, and a totem-pole circuit;
the first end of the filter capacitor is connected with the first end of the third winding, and the second end of the filter capacitor is grounded and used for filtering the voltage which is output by the sampling winding, has the same frequency as the voltage of the midpoint and has the same voltage phase;
the first end of the totem-pole circuit is connected with the third direct-current power supply, the second end of the totem-pole circuit is grounded, the control end of the totem-pole circuit is connected with the first end of the filter capacitor, and the output end of the totem-pole circuit is the output end of the conversion circuit and is used for outputting the common mode rejection signal based on the level of the first end of the filter capacitor.
7. A common-mode interference rejection circuit as in any one of claims 3, 4 and 6 wherein said totem-pole circuit comprises an NPN transistor and a PNP transistor;
the collector of the NPN type triode is the first end of the totem-pole circuit, and the emitter of the NPN type triode is connected with the emitter of the PNP triode; the collector of the PNP type triode is the second end of the totem-pole circuit; the base electrode of the NPN type triode is connected with the base electrode of the PNP type triode and is a control end of the totem-pole circuit; and the emitting electrode of the NPN type triode and the emitting electrode of the PNP type triode are connected and are output ends of the totem-pole circuit.
8. A common-mode interference rejection circuit as in any one of claims 3, 4 and 6 wherein said totem-pole circuit comprises PMOS transistors and diodes;
the drain electrode of the PMOS tube is the first end of the totem-pole circuit, the source electrode of the PMOS tube is connected with the anode of the diode and is the output end of the conversion circuit, and the grid electrode of the PMOS tube is connected with the cathode of the diode and is the control end of the totem-pole circuit.
9. A common-mode interference rejection circuit according to any one of claims 1 to 6, further comprising a rectifying diode disposed between said sampling winding and said conversion circuit for unidirectionally rectifying a voltage output from said sampling winding.
10. The common mode interference rejection circuit as in claim 1 wherein said resonant inductor and said transformer are integrated magnetic devices, and wherein leakage inductance of a primary winding and a secondary winding of said transformer is said resonant inductor; the sampling winding is a winding coupled with a primary winding of the transformer.
11. The common mode interference rejection circuit of claim 1 wherein said switched resonant circuit is a symmetric half-bridge resonant circuit or an asymmetric half-bridge resonant circuit.
12. The common mode interference rejection circuit as in claim 1 further comprising a resistor disposed between said conversion circuit and said common mode rejection capacitor.
CN202111349614.7A 2021-11-15 2021-11-15 Common mode interference suppression circuit Active CN114070036B (en)

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EP1085649A2 (en) * 1999-09-14 2001-03-21 Hitachi, Ltd. Power conversion system
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CN109039121A (en) * 2018-10-31 2018-12-18 深圳市高益智能电气有限公司 A kind of high-frequency isolation type ac-dc conversion circuit and its control method
CN110289752A (en) * 2019-07-05 2019-09-27 南京航空航天大学 It is a kind of inhibit LLC resonant converter common mode Conduction Interference common-mode voltage offset method and circuit
CN209659161U (en) * 2019-03-15 2019-11-19 乐金电子研发中心(上海)有限公司 A kind of full-bridge LLC converter
CN210958159U (en) * 2019-08-27 2020-07-07 联合汽车电子有限公司 Low common mode conducted interference's on-vehicle direct current conversion device
CN111740631A (en) * 2019-03-19 2020-10-02 台达电子工业股份有限公司 Resonant converter and method for manufacturing transformer thereof

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1085649A2 (en) * 1999-09-14 2001-03-21 Hitachi, Ltd. Power conversion system
CN106533195A (en) * 2016-12-15 2017-03-22 广东百事泰电子商务股份有限公司 Intelligent full-bridge sine-wave voltage switching circuit based on PFC and LLC resonance
CN109039121A (en) * 2018-10-31 2018-12-18 深圳市高益智能电气有限公司 A kind of high-frequency isolation type ac-dc conversion circuit and its control method
CN209659161U (en) * 2019-03-15 2019-11-19 乐金电子研发中心(上海)有限公司 A kind of full-bridge LLC converter
CN111740631A (en) * 2019-03-19 2020-10-02 台达电子工业股份有限公司 Resonant converter and method for manufacturing transformer thereof
CN110289752A (en) * 2019-07-05 2019-09-27 南京航空航天大学 It is a kind of inhibit LLC resonant converter common mode Conduction Interference common-mode voltage offset method and circuit
CN210958159U (en) * 2019-08-27 2020-07-07 联合汽车电子有限公司 Low common mode conducted interference's on-vehicle direct current conversion device

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