CN110601538A - Active clamp flyback converter - Google Patents

Active clamp flyback converter Download PDF

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Publication number
CN110601538A
CN110601538A CN201910746928.7A CN201910746928A CN110601538A CN 110601538 A CN110601538 A CN 110601538A CN 201910746928 A CN201910746928 A CN 201910746928A CN 110601538 A CN110601538 A CN 110601538A
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CN
China
Prior art keywords
clamping
signal
controller
frequency
tube
Prior art date
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Pending
Application number
CN201910746928.7A
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Chinese (zh)
Inventor
尹向阳
钟天明
马守栋
王志燊
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Mornsun Guangzhou Science and Technology Ltd
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Mornsun Guangzhou Science and Technology Ltd
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Priority to CN201910746928.7A priority Critical patent/CN110601538A/en
Publication of CN110601538A publication Critical patent/CN110601538A/en
Pending legal-status Critical Current

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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
    • 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
    • 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
    • H02M1/0048—Circuits or arrangements for reducing losses
    • H02M1/0054—Transistor switching losses
    • H02M1/0058—Transistor switching losses by employing soft switching techniques, i.e. commutation of transistors when applied voltage is zero or when current flow is zero
    • 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)
  • Dc-Dc Converters (AREA)

Abstract

The invention discloses an active clamp flyback converter, which comprises an active clamp circuit, a frequency jittering signal generator and a controller, and is characterized in that: the clamping capacitor is connected with a diode in parallel, or a clamping circuit is added on the basis; the frequency jittering signal generator is used for outputting a jittering signal with continuously changing voltage and sending the jittering signal into the controller, and after the controller loads the jittering signal generated by the frequency jittering signal generator, a modulation signal with continuously changing frequency is generated in the controller, and the modulation signal participates in the modulation of the signal in the controller, so that the controller outputs a driving signal with continuously changing frequency and provides the driving signal for the main switching tube. Compared with the prior art, the active clamping flyback converter has the advantages that the active clamping circuit is controlled to work in a frequency jittering mode, so that EMI generated by the active clamping flyback converter is spread and distributed on a wider frequency band, the conducted interference mean value generated by a power supply at a certain frequency point is reduced, the EMI is effectively reduced, the filtering pressure of a filter is relieved, and the use of the filter is reduced or avoided.

Description

Active clamp flyback converter
Technical Field
The invention relates to the field of switching converters, in particular to an active clamping flyback converter.
Background
With the rapid development of power electronic technology, the application of the switching converter is more and more extensive, and people have more and more requirements on the switching converter with high power density, high reliability and small volume. The common flyback topology has the advantages of simple structure, low price and the like, and is widely applied to small-power switch converters. However, the common flyback topology is a hard switch, and leakage inductance energy cannot be recovered, so that the efficiency and the volume of the common flyback topology are limited. In order to seek breakthrough in the volume and efficiency of small power switching converters, soft switching technology has become a hot research point in power electronic technology.
Currently, a flyback topology capable of implementing a soft switching technology is represented by an active clamp flyback circuit topology, and as shown in fig. 1, the flyback topology is composed of a main power circuit, a clamp circuit and an output filter circuit. The main power circuit is formed by connecting a transformer T1 and a main switching tube Q1, the clamping circuit is formed by connecting a clamping capacitor Cr and a clamping tube Q2, and the output filter circuit is formed by a rectifier diode DSRAnd the output capacitor Co, wherein Lm is an excitation inductor, Lr is a leakage inductor, a clamping circuit of the active clamping flyback converter can recover leakage inductor energy and transmit the leakage inductor energy to an output side, and when the main switch tube Q1 and the clamping tube Q2 are both switched off in a DCM (discontinuous conduction Mode), the excitation inductor Lm and the leakage inductor Lr of the active clamping flyback converter resonate with parasitic capacitors of the main switch tube and the clamping tube, so that soft switching is easily realized, and the conversion efficiency of the circuit is improved. However, in the DCM mode, the resonance between the excitation inductance Lm and the leakage inductance Lr of the active-clamp flyback converter and the parasitic capacitance of the switching tube will generate large oscillation, which deteriorates the EMI (Electro Magnetic Interference) of the circuit.
In order to realize soft switching of a flyback topology and obtain better EMI characteristics, Astec corporation proposes an active clamp flyback converter and a control method thereof, and the circuit topology is as shown in fig. 2, compared with a common active clamp flyback circuit, a clamp circuit of the active clamp flyback converter is formed by connecting a clamp capacitor and a clamp diode in parallel and then connecting the clamp capacitor and the clamp diode with a clamp tube. The active clamping flyback converter and the control method thereof provided by Astec company can realize soft switching of all switching tubes, can eliminate oscillation in intermittent rest stages, optimize EMI, and have working waveforms as shown in FIG. 3. However, fundamental oscillation generated during the circuit operation still exists, and a large conducted interference mean value still appears at the switching frequency and the frequencies of integral multiples of the switching frequency.
Disclosure of Invention
In order to solve the above problems, the present invention provides an active clamp flyback converter, which not only can realize soft switching of each switching tube, eliminate oscillation in the discontinuous rest stage of the flyback converter, but also can further reduce the average value of conducted interference generated by the circuit at the switching frequency and the integral multiple frequency points thereof.
The technical scheme provided by the invention is as follows:
an active clamp flyback converter comprises an active clamp circuit, a frequency jittering signal generator and a controller, and is characterized in that:
the active clamping circuit comprises a clamping tube Q2, a clamping capacitor Cr and a diode D4, wherein the clamping tube Q2 and the clamping capacitor Cr are connected in series and then connected in parallel at two ends of a primary winding of a transformer T1, the diode D4 is connected in parallel at two ends of the clamping capacitor Cr, the anode of a diode D4 is electrically connected with the positive input end of the active clamping flyback converter, and the cathode of a diode D2 is electrically connected with the negative input end;
the frequency jittering signal generator is used for outputting a jittering signal with continuously changing voltage and sending the jittering signal into the controller, after the controller loads the jittering signal generated by the frequency jittering signal generator, a modulation signal with continuously changing frequency is generated in the controller, the modulation signal participates in the modulation of the signal in the controller, so that the controller outputs a driving signal with continuously changing frequency and provides the driving signal for the main switching tube Q1 and the clamping tube Q2, and the main switching tube Q1 and the clamping tube Q2 are in a complementary relation.
An active clamp flyback converter comprises an active clamp circuit, a frequency jittering signal generator and a controller, and is characterized in that:
the active clamping circuit comprises a main clamping circuit and an auxiliary clamping circuit; the main clamping circuit comprises a main clamping tube Q4 and a main clamping capacitor Cr, wherein the main clamping tube Q4 and the main clamping capacitor Cr are connected in series and then are connected in parallel at two ends of a primary winding of a transformer T1 or a main switching tube Q1;
the auxiliary clamping circuit comprises an auxiliary clamping tube Q3 and an auxiliary clamping capacitor Cs, the auxiliary clamping tube Q3 and the auxiliary clamping capacitor Cs are connected in series and then connected in parallel to two ends of a primary winding of a transformer T1, the auxiliary clamping circuit further comprises a diode D2 connected in parallel with the auxiliary clamping capacitor Cs, the anode of the diode D2 is electrically connected with the positive input end of the active clamping flyback converter, and the cathode of the diode D2 is electrically connected with the negative input end;
the frequency jittering signal generator is used for outputting a jittering signal with continuously changing voltage and sending the jittering signal into the controller, after the controller loads the jittering signal generated by the frequency jittering signal generator, a modulation signal with continuously changing frequency is generated in the controller, the modulation signal participates in the modulation of the signal in the controller, so that the controller outputs a driving signal with continuously changing frequency and provides driving signals for the main switching tube Q1, the main clamping tube Q4 and the auxiliary clamping tube Q3, the main switching tube Q1 and the auxiliary clamping tube Q3 are in a complementary relation, the main clamping tube Q4 and the auxiliary clamping tube Q3 are simultaneously conducted, and when the secondary side current is zero, the main clamping tube Q4 is disconnected.
Preferably, the dither signal output by the dither signal generator is a triangular wave signal.
Preferably, the triangular wave signal is generated by an RC circuit or an integrating circuit.
Preferably, the dither signal output by the dither signal generator is a sine wave signal.
Preferably, the sine wave signal is generated by an LC resonant circuit.
Electrically coupling: the meaning includes direct or indirect connection, and also includes connection modes such as inductive coupling, for example, the cathode of the diode D2 is electrically connected with the negative input end, which is described in the present invention, and is indirect connection, and the auxiliary clamping tube Q3 and the main switching tube Q1 are also connected between the cathode and the negative input end of the diode D2.
The specific working principle of the present invention will be analyzed and explained in the specific embodiments, which are not described herein. Compared with the prior art, the invention has the beneficial effects that:
in the dither mode, the working frequency of the active clamping flyback circuit is continuously changed, so that the EMI generated by the active flyback converter is spread and distributed on a wider dither frequency band, the average value of conducted interference generated on the switching frequency and integral multiple frequency points of the switching frequency is effectively reduced, the filtering pressure of the filter is relieved, and the use of the filter is reduced or avoided.
Drawings
Fig. 1 is a schematic diagram of a circuit of a common active clamp flyback converter;
fig. 2 is a schematic diagram of an active clamp flyback converter circuit proposed by Astec;
fig. 3 is a working waveform diagram of an active clamp flyback converter circuit proposed by Astec;
fig. 4 is a waveform diagram of the operating frequency of the active clamp flyback converter of the present invention changing with time;
fig. 5 is a schematic diagram of an active clamp flyback converter according to a first embodiment of the present invention;
fig. 6 shows the operating waveforms of the active clamp flyback converter according to the first embodiment of the present invention;
fig. 7 is an input current waveform after fixed frequency mode fourier transform of the active clamp flyback converter according to the first embodiment of the present invention;
fig. 8 is a waveform of an input current after a frequency-jittering mode fourier transform of the active-clamp flyback converter according to the first embodiment of the present invention;
fig. 9 is a schematic diagram of an active clamp flyback converter according to a second embodiment of the present invention;
fig. 10 shows operating waveforms of an active clamp flyback converter according to a second embodiment of the present invention;
fig. 11 is an input current waveform after fixed frequency mode fourier transform of an active clamp flyback converter according to a second embodiment of the present invention;
fig. 12 is a diagram illustrating an input current waveform after a frequency-jittered mode fourier transform of an active-clamp flyback converter according to a second embodiment of the present invention.
Detailed Description
First embodiment
As shown in fig. 5, the active clamp flyback converter includes an active clamp circuit, a dither signal generator, and a controller, where the active clamp circuit includes a main power circuit, a clamp circuit, and an output filter circuit;
the main power circuit consists of a transformer T1 and a main switch tube Q1, a first terminal of a primary winding of the transformer is a positive input end of the circuit, a second terminal of the primary winding of the transformer is connected with a drain (a pole d) of a main switch tube Q1, and a source (a pole s) of the main switch tube Q1 is a negative input end;
the clamping circuit comprises a clamping tube Q2 and a clamping capacitor Cr, the clamping tube Q2 and the clamping capacitor Cr are connected in series and then connected in parallel at two ends of a primary winding of a transformer T1, the clamping circuit further comprises a diode D4 connected in parallel with the clamping capacitor Cr, the anode of the diode D4 is connected with the positive input end of the active clamping flyback converter, and the cathode of the diode D4 is electrically connected with the negative input end;
the output filter circuit is composed of a rectifier diode DSRAnd an output capacitor Co, a rectifier diode DSRThe anode of the rectifier diode D is connected with the first terminal of the secondary winding of the transformerSRThe cathode is connected with one end of an output capacitor Co to form a positive output end of the circuit, the other end of the output capacitor Co is connected with a second terminal of a secondary winding of the transformer to form a negative output end of the circuit, wherein Lm is an excitation inductor, and Lr is a leakage inductor;
the frequency jittering signal generator is used for outputting a jittering signal with continuously changing voltage and sending the jittering signal into the controller, after the controller loads the jittering signal generated by the frequency jittering signal generator, a modulation signal with continuously changing frequency is generated in the controller, the modulation signal participates in the modulation of the signal in the controller, so that the controller outputs a driving signal with continuously changing frequency and provides the driving signal for the main switching tube Q1 and the clamping tube Q2, the main switching tube Q1 and the clamping tube Q2 are in a complementary relation, and the working frequency of the circuit changes along with the load.
The dither signal generator may be a dither signal generator commonly known in the prior art, as shown in fig. 4, the triangular wave signal output by the dither signal generator may be generated by an RC circuit or an integrating circuit; the sine wave signal output by the dither signal generator may be generated by an LC resonant circuit.
The working process of the circuit of the embodiment includes 5 stages, namely an energy storage stage, a dead zone stage I, an energy transfer stage, a clamping freewheeling stage and a dead zone stage II, the working waveform diagram is shown in fig. 6, and the working process is as follows:
(1) energy storage stage (t 0-t 1 stage)
In the energy storage stage, the main switch tube Q1 is switched on, the clamping tube Q2 is switched off, and the secondary side rectifier diode DSRWhen turned off, the transformer T1 is excited in the forward direction.
(2) Dead zone stage one (t 1-t 2 stage)
In the first dead zone stage, the main switching tube Q1 and the clamping tube Q2 are turned off, the primary current first charges the parasitic capacitor of the main switching tube Q1, when the voltage of the parasitic capacitor of the main switching tube Q1 is greater than the input voltage Vin, the parasitic diode of the clamping tube Q2 is turned on, and the primary current charges the clamping capacitor Cr.
(3) Energy transfer stage (t 2-t 3 stage)
In the energy transfer stage, the main switch tube Q1 is turned off, the clamping tube Q2 is turned on, and the secondary side rectifier diode DSRThe voltage of the exciting inductor is clamped to-Nps Vo, the leakage inductor Lr resonates with the clamping capacitor Cr, and the resonant period isThis phase ends when the secondary current Is equals 0.
(4) Clamping freewheeling stage (t 3-t 4 stage)
In the clamping freewheeling stage, the main switch tube Q1 is turned off, the clamping tube Q2 is turned on, and the secondary side rectifier diode DSRAnd (6) cutting off. At the moment, the excitation inductor loses the clamping effect, the excitation inductor, the leakage inductor and the clamping capacitor resonate, when the voltage of the clamping capacitor drops to-0.7V, the diode D4 is conducted, at the moment, the excitation inductor is short-circuited, the resonance stops, the excitation current flows continuously through the diode D4 until the clamping tube Q2 is turned off, and the stage is ended.
(5) Dead zone stage two (t 4-t 5 stage)
In the second dead zone stage, the main switching tube Q1 and the clamping tube Q2 are turned off, the magnetizing inductor Lm and the leakage inductor Lr resonate with the parasitic capacitor of the main switching tube Q1 to discharge the parasitic capacitor of the main switching tube Q1, when the voltage of the parasitic capacitor of the main switching tube drops to 0, the parasitic diode of the main switching tube Q1 is turned on, at the moment, the main switching tube Q1 is turned on, and the main switching tube Q1 realizes ZVS.
The output current of the working process is subjected to Fourier transform, the transformed current waveform can reflect the EMI characteristic of the active clamp flyback converter, and compared with the waveform diagrams of fig. 7 and 8, in a fixed frequency mode, after Fourier transform, the peak value range of the input current is 0dBA to-54 dBA, in a frequency jitter mode, the peak value range of the input current is-12 dBA to-75 dBA, and compared with the fixed frequency mode, the input current peak value of the frequency jitter mode is reduced by about 10 dB. Therefore, in the dither frequency mode, the EMI generated by the active clamp flyback circuit is spread and distributed on a wider dither frequency band, so that the average conducted interference value generated by the active clamp flyback converter at the switching frequency and the integral multiple frequency point of the switching frequency is effectively reduced.
It should be noted that the diode D4 may be eliminated from the active clamp circuit of this embodiment, that is, the ordinary active clamp circuit in fig. 1 is adopted, and the claims are not protected because the EMI performance is poor.
Second embodiment
As shown in fig. 9, the present embodiment is different from the first embodiment in that the active clamp circuit includes a main clamp circuit and an auxiliary clamp circuit;
the main clamping circuit comprises a main clamping tube Q4 and a main clamping capacitor Cr, wherein the main clamping tube Q4 and the main clamping capacitor Cr are connected in series and then are connected in parallel at two ends of a primary winding of a transformer T1 or a main switching tube Q1; the auxiliary clamping circuit comprises an auxiliary clamping tube Q3 and an auxiliary clamping capacitor Cs, the auxiliary clamping tube Q3 and the auxiliary clamping capacitor Cs are connected in series and then connected in parallel to two ends of a primary winding of a transformer T1, the auxiliary clamping circuit further comprises a diode D2 connected in parallel with the auxiliary clamping capacitor Cs, the anode of the diode D2 is connected with the positive input electricity of the active clamping flyback converter, and the cathode of the diode D2 is electrically connected with the input electricity;
the frequency-jittering signal generator provides driving signals for a main switching tube Q1, a main clamping tube Q4 and an auxiliary clamping tube Q3 through a controller, the main switching tube Q1 and the auxiliary clamping tube Q3 are in a complementary relation, the main clamping tube Q4 and the auxiliary clamping tube Q3 are simultaneously conducted, and when the secondary side current is zero, the main clamping tube Q4 is turned off.
The working process of this embodiment is similar to that of the first embodiment, and also includes 5 stages, namely an energy storage stage, a first dead zone stage, an energy transfer stage, a clamping freewheeling stage, and a second dead zone stage, and a working waveform diagram is shown in fig. 10, except that a main clamping circuit is added, a clamping capacitor Cr of the main clamping circuit is a large capacitor, voltages at two ends of the large capacitor are basically kept unchanged, and in the energy transfer stage, the clamping capacitor Cr clamps the transformer to recover leakage inductance energy, so that high-frequency oscillation generated by leakage inductance of the transformer is eliminated.
Similarly, comparing the waveforms of fig. 11 and 12, the peak range of the input current after fourier transform is 0dBA to-52 dBA in the constant frequency mode, and the peak range of the input current is-13 dBA to-73 dBA in the dither mode, which is about 10dB lower than the peak value of the input current in the constant frequency mode. Therefore, in the dither frequency mode, the EMI generated by the active clamp flyback circuit is spread and distributed on a wider dither frequency band, so that the average conducted interference value generated by the active clamp flyback converter at the switching frequency and the integral multiple frequency point of the switching frequency is effectively reduced.
The above embodiments are only for the understanding of the inventive concept of the present application and are not intended to limit the present invention, and any modification, equivalent replacement, improvement, etc. made by those skilled in the art without departing from the principle of the present invention should be included in the protection scope of the present invention.

Claims (6)

1. An active clamp flyback converter comprises an active clamp circuit, a frequency jittering signal generator and a controller, and is characterized in that:
the active clamping circuit comprises a clamping tube Q2, a clamping capacitor Cr and a diode D4, wherein the clamping tube Q2 and the clamping capacitor Cr are connected in series and then connected in parallel at two ends of a primary winding of a transformer T1, the diode D4 is connected in parallel at two ends of the clamping capacitor Cr, the anode of a diode D4 is electrically connected with the positive input end of the active clamping flyback converter, and the cathode of a diode D2 is electrically connected with the negative input end;
the frequency jittering signal generator is used for outputting a jittering signal with continuously changing voltage and sending the jittering signal into the controller, after the controller loads the jittering signal generated by the frequency jittering signal generator, a modulation signal with continuously changing frequency is generated in the controller, the modulation signal participates in the modulation of the signal in the controller, so that the controller outputs a driving signal with continuously changing frequency and provides the driving signal for the main switching tube Q1 and the clamping tube Q2, and the main switching tube Q1 and the clamping tube Q2 are in a complementary relation.
2. An active clamp flyback converter comprises an active clamp circuit, a frequency jittering signal generator and a controller, and is characterized in that:
the active clamping circuit comprises a main clamping circuit and an auxiliary clamping circuit; the main clamping circuit comprises a main clamping tube Q4 and a main clamping capacitor Cr, wherein the main clamping tube Q4 and the main clamping capacitor Cr are connected in series and then are connected in parallel at two ends of a primary winding of a transformer T1 or a main switching tube Q1;
the auxiliary clamping circuit comprises an auxiliary clamping tube Q3 and an auxiliary clamping capacitor Cs, the auxiliary clamping tube Q3 and the auxiliary clamping capacitor Cs are connected in series and then connected in parallel to two ends of a primary winding of a transformer T1, the auxiliary clamping circuit further comprises a diode D2 connected in parallel with the auxiliary clamping capacitor Cs, the anode of the diode D2 is electrically connected with the positive input end of the active clamping flyback converter, and the cathode of the diode D2 is electrically connected with the negative input end;
the frequency jittering signal generator is used for outputting a jittering signal with continuously changing voltage and sending the jittering signal into the controller, after the controller loads the jittering signal generated by the frequency jittering signal generator, a modulation signal with continuously changing frequency is generated in the controller, the modulation signal participates in the modulation of the signal in the controller, so that the controller outputs a driving signal with continuously changing frequency and provides driving signals for the main switching tube Q1, the main clamping tube Q4 and the auxiliary clamping tube Q3, the main switching tube Q1 and the auxiliary clamping tube Q3 are in a complementary relation, the main clamping tube Q4 and the auxiliary clamping tube Q3 are simultaneously conducted, and when the secondary side current is zero, the main clamping tube Q4 is disconnected.
3. The active-clamp flyback converter of claim 1 or 2, wherein: the dither signal output by the dither signal generator is a triangular wave signal.
4. The active-clamp flyback converter of claim 3, wherein: the triangular wave signal is generated by an RC circuit or an integrating circuit.
5. The active-clamp flyback converter of claim 1 or 2, wherein: the dither signal output by the dither signal generator is a sine wave signal.
6. The active-clamp flyback converter of claim 5, wherein: the sine wave signal is generated by an LC resonant circuit.
CN201910746928.7A 2019-08-14 2019-08-14 Active clamp flyback converter Pending CN110601538A (en)

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Application Number Priority Date Filing Date Title
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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111030468A (en) * 2019-12-26 2020-04-17 广州金升阳科技有限公司 Control method and control circuit of clamping switch power supply
CN114285291A (en) * 2021-12-30 2022-04-05 中国科学院电工研究所 Topology improvement structure and method of high-frequency high-power photovoltaic medium-voltage direct-current converter

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111030468A (en) * 2019-12-26 2020-04-17 广州金升阳科技有限公司 Control method and control circuit of clamping switch power supply
CN114285291A (en) * 2021-12-30 2022-04-05 中国科学院电工研究所 Topology improvement structure and method of high-frequency high-power photovoltaic medium-voltage direct-current converter

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