CN113872450A - ZVS self-adaptive control method and circuit of active clamp converter - Google Patents

ZVS self-adaptive control method and circuit of active clamp converter Download PDF

Info

Publication number
CN113872450A
CN113872450A CN202111306671.7A CN202111306671A CN113872450A CN 113872450 A CN113872450 A CN 113872450A CN 202111306671 A CN202111306671 A CN 202111306671A CN 113872450 A CN113872450 A CN 113872450A
Authority
CN
China
Prior art keywords
converter
switch tube
zvs
clamping
voltage
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN202111306671.7A
Other languages
Chinese (zh)
Inventor
刘华吾
曹赟
王廷营
赵瑞
崔满超
唐海瑞
王永生
丁星星
戚宏伟
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Shanghai Jieruizhao New Information Technology Co ltd
Original Assignee
Shanghai Jieruizhao New Information Technology Co ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Shanghai Jieruizhao New Information Technology Co ltd filed Critical Shanghai Jieruizhao New Information Technology Co ltd
Priority to CN202111306671.7A priority Critical patent/CN113872450A/en
Publication of CN113872450A publication Critical patent/CN113872450A/en
Pending legal-status Critical Current

Links

Images

Classifications

    • 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
    • H02M1/08—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
    • H02M1/088—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters for the simultaneous control of series or parallel connected semiconductor devices
    • 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
    • H02M3/33507—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 with automatic control of the output voltage or current, e.g. flyback converters
    • H02M3/33515—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 with automatic control of the output voltage or current, e.g. flyback converters with digital control
    • 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
    • H02M3/33507—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 with automatic control of the output voltage or current, e.g. flyback converters
    • H02M3/33523—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 with automatic control of the output voltage or current, e.g. flyback converters with galvanic isolation between input and output of both the power stage and the feedback loop
    • 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

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Dc-Dc Converters (AREA)

Abstract

The invention discloses a ZVS self-adaptive control method and a ZVS self-adaptive control circuit for an active clamp converter, wherein the method comprises the following steps: collecting input voltage v of active clamp type converter topologyinsOutput voltage vosAnd the drain-source voltage v of the main switch tube Q1dsp(ii) a Respectively obtaining the conduction time values T of the main switch tube Q1 and the clamping switch tube Q21And T2(ii) a According to the on-time value T1And T2Acquiring driving pulses QS1 and QS2 of a main switching tube Q1 and a clamping switching tube Q2; to the drain-source voltage vdspAnd the driving pulse is subjected to logic operation and driving capacity amplification to generate a power driving signal Qg1And Qg2The main switch tube Q1 and the clamping switch tube Q2 are respectively driven, and the ZVS operation of the converter is realized. The invention can realize ZVS turn-on of the active clamping converter in a self-adaptive manner, and has the excellent characteristics of convenient realization and wide application range.

Description

ZVS self-adaptive control method and circuit of active clamp converter
Technical Field
The invention belongs to the technical field of converter control, and particularly relates to a ZVS (zero voltage switching) self-adaptive control method and circuit of an active clamp converter.
Background
With the development of modern electronic systems, the requirements of high-power-density and high-efficiency switching power converters are more and more extensive, and active clamp converters, such as active clamp flyback converters, active clamp forward converters, double-clamp ZVS converters and the like, are widely researched and applied in academia and industry due to the excellent characteristics of high efficiency, full-range soft switching, high switching frequency adaptation and the like.
Fig. 1 shows a typical topology of an active clamp class topology-an active clamp flyback converter. First switch tube Q1The high-frequency chopping switch tube is used for controlling the output voltage of the converter; second switch tube Q2Is a clamping switch tube, which is matched with a clamping capacitor CcFor recycling transformer TrLeakage inductance energy of (d); in addition, the clamping switch tube Q is reasonably controlled2Can realize the first switch tube Q1The Zero Voltage (ZVS) turn-on characteristic of the converter to reduce the switching losses of the converter to improve the efficiency of the converter. The transformer TrSecondary side connected with a first diode D1Filter capacitor CLdAnd an output load RLd。
The key technology of the active clamping type converter is to effectively control a clamping switch tube to realize that a main switch tube realizes zero voltage switching-on in a full input voltage and full load range so as to improve the efficiency of the converter. Chinese invention patent CN111953185A provides a control method of active clamp flyback topology self-adaptive dead time, which realizes ZVS control of a main switch tube by connecting a sampling resistor in series with a main switch tube loop at the primary side of a converter to sample the leakage inductance current of the transformer, although the method is simple and effective, the extra sampling resistor will increase the converter loss and influence the converter efficiency; on the other hand, because the sampling resistance is small, the sampled current signal is weak, the system is very easy to be interfered, and the method is limited in the application occasions with high switching frequency and high power density. The invention patent CN111682769A in China provides an active clamping forward converter and a self-adaptive synchronous rectification digital control method thereof, the method predicts the moment when the current in a filter inductor reaches zero through a DSP theoretical calculation mode, and the converter is controlled in a self-adaptive mode, however, the theoretical calculation mode has higher requirement on the parameter consistency of the converter, and the reliable operation of the converter in a large dynamic scene cannot be ensured reliably. The invention patent US9083254B1 proposes a scheme that the driving of the sampling secondary side synchronous rectifier controls the clamp switching tube through the isolator for the double-clamp ZVS converter, however, the implementation of the aspect is complex, an additional isolating circuit is required, and the implementation of the small volume and high power density of the switching power supply is not facilitated. The invention patent US10418912B2 proposes that the scheme such as delay circuit, main switch drain-source voltage "key inflection point" is used to realize the control of the on-time of the clamp switch tube for the active clamp flyback converter, the scheme is relatively complex, the dependence on the main switch drain-source voltage "key inflection voltage" is high, and the reliability of the converter system is not facilitated.
Disclosure of Invention
The present invention is directed to a ZVS adaptive control method and circuit for an active clamp converter, which solves the above problems of the prior art.
The technical solution for realizing the purpose of the invention is as follows: a ZVS adaptive control method of an active clamp class converter, the method comprising the steps of:
step 1, collecting input voltage v of active clamping type converter topologyinsOutput voltage vosAnd the drain-source voltage v of the main switch tube Q1dsp；
Step 2, mining according to step 1Sampling to obtain the conduction time T of the main switch tube Q1 and the clamping switch tube Q21And T2；
Step 3, according to the conduction time value T1And T2Acquiring driving pulses QS1 and QS2 of a main switching tube Q1 and a clamping switching tube Q2;
step 4, drain-source electrode voltage vdspAnd the driving pulse is subjected to logic operation and driving capacity amplification to generate a power driving signal Qg1And Qg2The main switch tube Q1 and the clamping switch tube Q2 are respectively driven, and the ZVS operation of the converter is realized.
Further, in step 2, the conduction time value T of the main switching tube Q1 is obtained according to the sampling value in step 11The specific process comprises the following steps:
step 21-1, input voltage vinsOutput voltage vosThe sampling value carries out closed-loop regulation on the output voltage of the converter through a proportional-integral regulator;
step 21-2, based on the output value v of the proportional-integral regulatorerObtaining the conduction time T of the main switch tube Q11。
Further, in step 2, the conduction time value T of the clamping switch tube Q2 is obtained according to the sampling value in step 12The specific process comprises the following steps:
step 22-1, the conduction time T of the main switch tube Q11Obtaining the conduction time T of the clamping switch tube Q2 through volt-second balance20；
Step 22-2, drain-source voltage v of main switch tube Q1dspObtaining v via a comparatorplsA signal;
step 22-3, acquiring v by pulse width captureplsDuration of low level of signal Tps；
Step 22-4, low level duration TpsMinus the conduction time T of the last switching period clamping switching tube Q22Obtaining a characteristic time value T for identifying the ZVS characteristic of the main switching tube Q1psf；
Step 22-5, for the characteristic time value TpsfPerforming proportional-integral closed-loop regulation to obtain the switching time of the clamping switching tube Q2Adjustment value dTz；
Step 22-6, adjusting the switch time to a value dTzIs superimposed on T20Obtaining the final conduction time value T of the clamping switch tube Q22。
Further, the pair of drain-source voltages v of step 4dspAnd the driving pulse is subjected to logic operation and driving capacity amplification to generate a power driving signal Qg1And Qg2The specific process comprises the following steps:
step 4-1, drain-source voltage v of the main switch tube Q1dspObtaining Q via a comparatorspA signal;
step 4-2, said QspThe signal and QS2 signal are passed through a two-input AND gate to get Qsp2A signal;
step 4-3, said Qsp2The signal and QS1 signal output Q after passing through a half-bridge driving circuitg1And Qg2The two signals respectively drive the main switch tube Q1 and the clamping switch tube Q2.
A ZVS adaptive control circuit for an active clamp class converter, the circuit comprising: the circuit comprises an active clamping flyback converter, a digital controller, an isolation sampling circuit, a first resistance voltage division sampling circuit, a second resistance voltage division sampling circuit and a driving and control circuit; the main power circuit of the active clamp flyback converter comprises a main switching tube Q1 and a clamp switching tube Q2;
the output voltage V of the active clamp flyback converteroConversion to analog sampled signal v via isolated sampling circuitosThe digital controller is connected to the converter for closed-loop control of the flyback converter; input voltage source V of active clamp flyback converterinConverted into an analog sampling signal v through a first resistor voltage division sampling circuitinsThe digital controller is connected to the main switching tube Q1 and the clamping switching tube Q2 of the flyback converter and is used for calculating the on-time parameters of the main switching tube Q1 and the clamping switching tube Q2; the drain-source voltage V of the main switching tube Q1 of the active clamping flyback converterdsQ1Converted into an analog sampling signal v through a second resistor voltage-dividing sampling circuitdspIs connected to the digital controller and is used for realizing the self-adaptive ZVS control of the flyback converter main switching tube Q1(ii) a The digital controller outputs drive pulses QS1 and QS 2; the driving pulses QS1 and QS2 and the output signal v of the second resistance voltage division sampling circuitdspConnected to a drive and control circuit which outputs a drive signal Qg1And Qg2The main switch tube Q1 and the clamping switch tube Q2 of the flyback converter are respectively driven.
Further, the digital controller comprises an output voltage closed-loop regulation module, a Q1 and Q2 switching tube on-time parameter calculation module, a pulse width extraction module, a pulse width closed-loop regulation module and a PWM generation module;
sampling value v of output voltageosIs connected to an output voltage closed-loop regulation module for closed-loop control of the output voltage of the active clamp flyback converter to perform proportional-integral regulator operation, i.e. ver＝(kp+ki/s)×(Voref-vos) In which V isorefRepresenting the converter output voltage reference value, kpAnd kiProportional and integral coefficient constants, respectively; drain-source voltage vdspThe pulse width extraction module and the pulse width closed-loop regulation module output a pulse width regulation output value dTzAs a switching time adjustment value of the clamp switching tube Q2; regulator output value verSampling value v of input voltageinsSampling value v of output voltageosAnd pulse width modulation output value dTzThe switching tube on-time parameter calculation modules are connected to the Q1 and the Q2 and are used for calculating on-time parameters T1 and T2 of the main switching tube Q1 and the clamping switching tube Q2; the on-time parameters T1 and T2 generate drive pulses QS1 and QS2 of the main switching tube Q1 and the clamp switching tube Q2 via a PWM generation module.
Further, the on-time parameter T of the main switch tube Q1 and the clamping switch tube Q21And T2The calculation formulas of (A) and (B) are respectively as follows:
Figure BDA0003340380050000041
Figure BDA0003340380050000042
in the formula, n represents the primary and secondary side turn ratio of the transformer of the flyback converter.
Further, the pulse width extraction module and the pulse width closed-loop regulation module comprise a first analog comparator, a pulse width capture module and a PI regulator;
drain-source voltage vdspThreshold value vth2Connected to the positive and negative terminals, respectively, of a first analog comparator whose output signal v isplsConnected to a pulse width capture module for obtaining vplsHigh level duration Tps，TpsSubtracting the time T by a subtractor2Obtaining a characteristic time length Tpsf，TpsfAnd a reference time TrefObtaining a difference value T by a subtracterer，TerThe switching time adjustment value dT of the clamping switching tube Q2 is output through a PI regulatorz。
Furthermore, the driving and controlling circuit comprises a second analog comparator, a double-input AND gate and a half-bridge driving circuit;
drain-source voltage vdspComparator reference vth1Connected to the negative and positive terminals of a second analog comparator, respectively, the output signal Q of whichspQS2 output by the PWM generating module is respectively connected to two input ends of a double-input AND gate, and an output signal Q of the double-input AND gatesp2QS1 output by the PWM generation module is connected to a half-bridge driving circuit which outputs two driving signals Qg1And Qg2The main switch tube Q1 and the clamping switch tube Q2 of the flyback converter are respectively driven.
The method indirectly obtains the characteristic information of the ZVS characteristic of the main switching tube by sampling the DS voltage of the drain electrode of the main switching tube, realizes the self-adaptive adjustment of the opening time of the clamping switching tube by combining the volt-second balance and the adjustment value obtained by closed-loop control of the characteristic information, realizes the closed-loop control of the negative current of the transformer, and finally realizes the reliable ZVS work of the main switching tube and the clamping switching tube of the active clamping topology by combining a specific logic circuit, and compared with the prior art, the method has the remarkable advantages that: 1) the DS voltage sampling is carried out only through the resistor, the sampling scheme is simple and convenient, the application range is wide, compared with the existing shunt sampling scheme, the sampling scheme is small in size, extra loss cannot be introduced, and the sampling scheme has a great benefit for improving the power density of the converter; 2) by carrying out closed-loop self-adaptive adjustment on the negative current, the magnitude of the negative current of the converter is not influenced by factors such as input voltage, output load and the like of the converter, and the soft opening of the converter under all working conditions is favorably realized; 3) the leakage source level voltage signal of the main switching tube is sampled through the resistor, and the signal has the advantages of large amplitude, obvious characteristic information, high reliability and strong anti-interference capability.
The present invention is described in further detail below with reference to the attached drawing figures.
Drawings
Fig. 1 is a schematic diagram of an active clamp flyback converter.
Fig. 2A is a schematic diagram of an active clamp flyback converter and its key voltage points.
Fig. 2B is a diagram of a possible exemplary waveform B of an active-clamp flyback converter.
Fig. 2C is a diagram of a possible typical waveform C of an active-clamp flyback converter.
Fig. 2D is a diagram of a possible typical waveform D of an active-clamp flyback converter.
Fig. 2E is a diagram of a possible typical waveform E of an active-clamp flyback converter.
Fig. 3A is a schematic diagram of mode a of the active-clamp flyback converter.
Fig. 3B is a schematic diagram of mode B of the active-clamp flyback converter.
Fig. 3C is a schematic diagram of mode C of the active-clamp flyback converter.
Fig. 3D is a mode D schematic diagram of the active-clamp flyback converter.
Fig. 4 is a flowchart of an adaptive ZVS control method for an active clamp converter according to an embodiment of the present invention.
FIG. 5 is a block diagram of an embodiment of the present invention.
FIG. 6 is a block diagram of a driving and controlling circuit according to an embodiment of the present invention.
Fig. 7 is a block diagram of pulse width extraction and closed-loop adjustment of pulse width according to an embodiment of the present invention.
Fig. 8 is a block diagram of an implementation of a dual-clamp ZVS buck-boost converter according to an embodiment of the invention.
Fig. 9 is a waveform diagram of a test prototype according to an embodiment of the present invention.
Detailed Description
The technical solutions in the examples of the present application will be described clearly and completely with reference to the accompanying drawings in the examples of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all embodiments, and all other embodiments obtained by those skilled in the art without any inventive work based on the embodiments in the present application belong to the protection scope of the present application.
In the embodiment of the present application, an active clamp flyback converter is used as an embodiment, and it should be noted that the scheme of the present application is also applicable to other active clamp topologies such as an active clamp forward converter, a dual-clamp ZVS buck-boost converter, and the like.
To illustrate the key technology of the present invention, a detailed description will be made below with reference to fig. 2A to 2E and fig. 3A to 3D. FIG. 2A shows a topology diagram of an active clamp flyback converter, selecting a transformer TrExcitation current i ofLmTransformer leakage inductance LrCurrent i ofLrThe driving of a main switch tube Q1 and a clamping switch tube Q2 and the drain-source voltage V of the main switch tubedsQ1All leakage inductance ground currents i with the working waveforms as the research focusLrAs shown in fig. 2A.
Referring to fig. 2B, one switching period of the active clamp flyback converter is mainly divided into three time periods t 0-t 1, t 1-t 2, t 2-t 3, and the like. Referring to fig. 3A, in the time period from T0 to T1, the main switch tube Q1 is turned on, and the primary side of the converter is supplied to the transformer T from the input voltage source Vin via the main switch tube Q1rExciting, disconnecting secondary side of converter, and filtering by output filter capacitor CLdTo a load RLdAnd supporting power supply. At this stage, exciting the inductive current iLmAnd leakage inductance current iLrThe synchronous line rises. Referring to fig. 3B, during the period t 1-t 2, the main switching tube Q1 is turned off,when the clamping switch tube Q2 is switched on, the exciting inductive current is linearly reduced on one hand, and the transformer T is on the other handrThe secondary side is conducted, the secondary side current is refracted to the primary side, and the leakage inductance current iLrThe resonance is reduced; at time T1_2, the leakage inductance current and the excitation inductance current are equal, and the transformer TrSecondary side is released and filter capacitor C is outputLdTo a load RLdAnd supporting power supply. Referring to fig. 3C, at the stage t1_2 to t2, since the clamp switching tube Q2 is continuously turned on, the voltage of the clamp capacitor is continuously applied to the primary side of the transformer, and the magnetizing current i is inducedLmAnd a resonant current iLrThe synchronous descending is continued until the clamping switch tube Q2 is closed at the time t2, and the exciting current i is normally excited at the time t2LmThe drop is negative. Referring to fig. 3D, in the time period from t2 to t3, the main switch tube Q1 and the clamping switch tube Q2 are both turned off, and the exciting inductive current iLmThe parasitic capacitor of the main switch tube Q1 is discharged, meanwhile, the parasitic capacitor of the clamping switch tube Q2 is charged, the drain-source voltage of the Q1 switch tube is gradually reduced, and the drain-source voltage V of the Q1 switch tube is the drain-source voltage V of the Q1 switch tube after the parasitic capacitor of the main switch tube Q1 is completely dischargeddsQ1When the voltage drops to 0, the main switch tube Q1 is switched on, the converter is switched on in the next switching period, and at the moment, the main switch tube Q1 is switched on at zero voltage, so that the switching loss of Q1 is reduced, and the efficiency of the converter is improved.
The reliable realization of zero voltage switching-on of a main switching tube of the active clamping flyback converter is a key technology for improving the converter. In the period from t2 to t3, namely the dead time of the main switch tube and the clamping switch tube, the exciting current i of the transformer isLmWhether the parasitic capacitance energy of the main switching tube can be effectively discharged or not directly determines whether the main switching tube Q1 can effectively realize ZVS or not. Referring to fig. 2B and 3D, the exciting current at time t2 is set to-iLmT2, while assuming iLmT2 is large enough, and considering that the inductance of the exciting inductor is much larger than the parasitic capacitance of the main switch tube and the clamping switch tube, the transformer TrThe discharge time of the exciting current is as follows,
Figure BDA0003340380050000061
wherein C isoss1And Coss2Respectively refer to the parasitic capacitance of the main switch tube Q1 and the clamping switch tube Q2. It can be seen from the equation (1) that the time when the excitation current leaks out the parasitic capacitance and the excitation current iLm_t2The reverse proportion is in inverse proportion, namely the larger the reverse excitation inductive current value at the time t2 is, the shorter the required discharge time is; otherwise, the longer the bleed-off time.
Referring to fig. 2B-2D, the operating waveforms of the converter corresponding to the exciting inductor current at different times t2 are shown. In fig. 2C, the turn-on time of the clamping switch Q2 is slightly longer than that in fig. 2B, so that the reverse excitation current i at time t2Lm_t2The voltage of the main switching tube Q1 and the parasitic capacitance of the clamping switching tube Q2 are discharged quickly at the time t 2-t 3, and ZVS (zero voltage switching) opening of the main switching tube Q1 is guaranteed reliably. However, an excessive reverse excitation current inevitably causes conduction loss of the transformer to be large, which affects the efficiency of the converter. In fig. 2D, the on-time of the clamping switch Q2 is slightly shorter than that in fig. 2B, which makes the transformer reverse excitation current i at the time point t2Lm_t2Although the conduction loss of the transformer is reduced, the time for the exciting current to drain the parasitic capacitors of the Q1 and the Q2 is prolonged, and after the dead time is over, the parasitic capacitor charge of the Q1 is still not drained, that is, the ZVS switching-on of the main switching tube Q1 cannot be reliably realized. In addition, when the input voltage or the output load changes, the reverse excitation current iLm_t2And will change, how to reliably ensure ZVS switching of the switching tube Q1 is a key issue.
Further, referring to fig. 2E, the excitation current i at the time t2, i.e. the turn-off time of the clamping tube Q2Lm_t2If the voltage is too small, the time for the exciting current to drain the parasitic capacitance will be longer, and the drain-source voltage of the Q1 switch tube cannot resonate to zero level in the time period from t2 to t3, which means that the main switch tube Q1 cannot realize ZVS soft switching, which seriously affects the conversion efficiency of the converter.
Further, as can be seen from fig. 2B to 2D, the larger the transformer reverse excitation current is at time t2, the smaller the time period for the main switching tube Q1 to resonate to zero voltage after the clamping switching tube Q2 is turned off, and vice versa; referring to fig. 2E, if the reverse excitation current of the transformer is too small at time t2, the resonance of the main switching tube Q1 cannot resonate to zero voltage, that is, the time period of the resonance of the main switching tube Q1 to zero voltage after the clamping switching tube Q2 is turned off is "infinitely long"; in summary, the time length from resonance to zero voltage of the main switching tube Q1 after the clamping switching tube Q2 is turned off can indirectly reflect the magnitude of the reverse excitation current of the transformer, the turn-on of the main switching tube Q1 ZVS can be reliably ensured by reasonably controlling the time length, and the control of the time length from resonance to zero voltage can be realized by controlling the turn-on time of the main switching tube Q2.
In one embodiment, in conjunction with fig. 4, there is provided a ZVS adaptive control method of an active clamp class converter, the method comprising the steps of:
step 1, collecting input voltage v of active clamping type converter topologyinsOutput voltage vosAnd the drain-source voltage v of the main switch tube Q1dsp；
Step 2, respectively obtaining the conduction time values T of the main switch tube Q1 and the clamping switch tube Q2 according to the sampling values in the step 11And T2；
Step 3, according to the conduction time value T1And T2Acquiring driving pulses QS1 and QS2 of a main switching tube Q1 and a clamping switching tube Q2;
step 4, drain-source electrode voltage vdspAnd the driving pulse is subjected to logic operation and driving capacity amplification to generate a power driving signal Qg1And Qg2The main switch tube Q1 and the clamping switch tube Q2 are respectively driven, and the ZVS operation of the converter is realized.
Further, in one embodiment, in step 2, the conduction time value T of the main switch Q1 is obtained according to the sampling value in step 11The specific process comprises the following steps:
step 21-1, input voltage vinsOutput voltage vosThe sampling value carries out closed-loop regulation on the output voltage of the converter through a proportional-integral regulator;
step 21-2, based on the output value v of the proportional-integral regulatorerObtaining the conduction time T of the main switch tube Q11。
Further, in one embodiment, the conduction time value T of the clamping switch tube Q2 is obtained according to the sampling value in step 1 in step 22The specific process comprises the following steps:
step 22-1, the conduction time T of the main switch tube Q11Obtaining the conduction time T of the clamping switch tube Q2 through volt-second balance20；
Step 22-2, drain-source voltage v of main switch tube Q1dspObtaining v via a comparatorplsA signal;
step 22-3, acquiring v by pulse width captureplsDuration of low level of signal Tps；
Step 22-4, low level duration TpsMinus the conduction time T of the last switching period clamping switching tube Q22Obtaining a characteristic time value T for identifying the ZVS characteristic of the main switching tube Q1psf；
Step 22-5, for the characteristic time value TpsfPerforming proportional integral closed-loop regulation to obtain a switching time adjustment value dT of the clamping switching tube Q2z；
Step 22-6, adjusting the switch time to a value dTzIs superimposed on T20Obtaining the final conduction time value T of the clamping switch tube Q22。
Further, in one embodiment, the pair of drain-source voltages v of step 4dspAnd the driving pulse is subjected to logic operation and driving capacity amplification to generate a power driving signal Qg1And Qg2The specific process comprises the following steps:
step 4-1, drain-source voltage v of the main switch tube Q1dspObtaining Q via a comparatorspA signal;
step 4-2, said QspThe signal and QS2 signal are passed through a two-input AND gate to get Qsp2A signal;
step 4-3, said Qsp2The signal and QS1 signal output Q after passing through a half-bridge driving circuitg1And Qg2The two signals respectively drive the main switch tube Q1 and the clamping switch tube Q2.
Referring to fig. 5, a schematic block diagram of an embodiment of the present invention includes an active clamp flyback main power circuit 400, a digital controller 410, an isolation sampling circuit 401, a first resistance voltage division sampling circuit 402, a second resistance voltage division sampling circuit 404, and a driving and control circuit 403, where the digital controller 410 further includes modules 411 to 415.
Specifically, active clamp flyback converter output voltage VoConversion to analog sampled signal v via isolated sampling circuit 401osConnected to the digital controller 410 for closed loop control of the flyback converter; input voltage source V of flyback converterinConverted into an analog sampling signal v via the first resistor divider sampling circuit 402insThe digital controller 410 is connected to calculate the on-time parameter calculation of the main switching tube Q1 and the clamping switching tube Q2 of the flyback converter; the drain-source voltage V of the main switch tube Q1 of the flyback converterdsQ1Converted into an analog sampling signal v via a second resistor divider sampling circuit 404dspIs connected to the digital controller 410 and is used for realizing the self-adaptive ZVS control of the main switching tube Q1 of the converter; the digital controller 410 outputs pulse width driving signals QS1 and QS 2; the pulse width signals QS1 and QS2 and the output signal v of the second resistance voltage division sampling circuit 404dspConnected to the driving and control circuit 403; the driving and control circuit 403 outputs a driving signal Qg1And Qg2The main switch tube Q1 and the clamping switch tube Q2 of the flyback converter are directly driven.
Specifically, the digital controller 410 module comprises 411-415 modules. Sampling value v of output voltageosIs connected to an output voltage closed loop regulation module 411 which outputs a signal regulator output value verThe on-time parameter calculation module 412 connected to the Q1 and Q2 switch tubes; the output voltage closed-loop regulation module 411 is used for closed-loop control of the output voltage of the active clamp flyback converter, and mainly performs proportional-integral regulator operation, namely ver＝(kp+ki/s)×(Voref-vos) (ii) a Wherein VorefRepresenting the converter output voltage reference value, kpAnd kiRespectively, proportional and integral coefficient constants, the specific value can be converted according to four switchesThe specific working condition of the device is optimally designed. The regulator output verSampling value v of input voltageinsSampling value v of output voltageosAnd a pulse width modulation output dTzThe four input signals are connected to the Q1 and Q2 switch tube on-time parameter calculation module 412. The module 412 is used for calculating the on-time parameter T of the main switch Q1 and the clamp switch Q2 of the flyback converter1And T2The detailed calculation formula is as follows:
Figure BDA0003340380050000091
Figure BDA0003340380050000092
t in the formula (2)1Representing the turn-on time of the main switch tube of the flyback converter, its calculated value and the input voltage VinThe voltage is inversely proportional to improve the dynamic response of the converter under the condition of input voltage jump; t is1Is simultaneously equal to the output value V of the output voltage closed-loop regulation module 411erIs in direct proportion to realize the voltage stabilization control of the output voltage of the flyback converter. When the output voltage V isoIncrease T when falling1Time, conversely, at the output voltage VoAt the time of rising, T is decreased1Time.
Wherein, n in the formula (3) represents the primary and secondary side turn ratio of the transformer of the flyback converter. The formula (3) is composed of two terms, the first term
Figure BDA0003340380050000093
This is obtained from the volt-second balance of the transformer; second term T21＝dTzThe method is used for fine tuning the conduction time of the clamping switch tube, so as to realize accurate control of the negative current of the transformer exciting current at the turn-off moment of the clamping tube (see t of fig. 2B)2Time) to reliably guarantee ZVS of the main switching tube Q1 to improve the efficiency of the converter. The T is21＝dTzObtained by the pulse width closed loop adjustment module 414 in the digital controller shown in figure 4,the specific mechanism of this module will be described in detail below.
The first term in said formula (3) will be explained below
Figure BDA0003340380050000101
The physical mechanism of (1). Referring to fig. 2B, in a time period from t0 to t1, a main switching tube Q1 of the flyback converter is turned on, an input voltage is applied to a primary side of the transformer, a transformer exciting current linearly rises, and an exciting current change amount is as follows:
Figure BDA0003340380050000102
wherein iLm_t1And iLm_t0The currents, L, of the excitation inductor at times t1 and t0, respectivelymIndicating the value of the excitation inductance.
Referring to fig. 2B, when the main switching tube Q1 is turned off in a time period from t1 to t2, the clamp switching tube Q2 is turned on, the voltage of the clamp capacitor is reversely applied to the primary side of the transformer of the flyback converter, the exciting current of the transformer is linearly decreased, and the exciting current variation is as follows:
Figure BDA0003340380050000103
wherein iLm_t2And iLm_t1The currents, v, of the excitation inductor at times t2 and t1, respectivelyclpThe voltage of the clamping capacitor is equal to the voltage that the output voltage refracts to the primary side of the transformer, namely v under the steady state working conditionclp＝n×vos. Obviously, under the steady-state working condition, the excitation inductance of the active clamp flyback converter needs to satisfy volt-second balance, that is:
iLm_t1-iLm_t0＝iLm_t1-iLm_t2 (6)
thus, it is possible to prevent the occurrence of,
Figure BDA0003340380050000104
it should be noted that the above derivation ignores the leakage inductance of the transformer and the dead time of the flyback converter main switch Q1 and the clamp switch Q2, so the equation (7) is only an approximation, which is to introduce the second term T of the equation (3)21＝dTzReason for (dT)zThe method and the device can adaptively adjust the turn-on time of the clamping switch tube Q2, and ensure that the reliable ZVS turn-on of the main switch tube Q1 can be realized under different input voltages and different load conditions.
Referring to fig. 5, in detail, the Q1 and Q2 switch tube on-time parameter calculation module 412 outputs T1And T2The time parameter is connected to the PWM generating module 415 to generate PWM signals QS1 and QS2, the signals QS1 and QS2 and the second resistance voltage division sampling circuit 404 output the signal vdspConnected together to the input of a drive and control circuit 403, said drive and control circuit 403 eventually generating a drive signal Q1 for the main switch Q1 and the auxiliary switch Q2 of the active-clamp flyback converterg1And Qg2。
Referring to fig. 6, which is a block circuit diagram of the driving and control circuit, the module is further divided into a second analog comparator 500, a dual-input and gate 501 and a half-bridge driving circuit 502. The positive input end of the analog comparator 500 is connected with the reference v of the second analog comparator 500th1The reference value is usually about 1V, and the negative input end of the second analog comparator 500 is connected with the value V of the drain-source voltage of the main switching tube Q1 after resistance samplingdsp. The second analog comparator 500 outputs a signal QspIs connected to one end of a two-input and gate 501, the other end of which is connected to the output signal QS2 of the PWM generation block 415 in fig. 5, which outputs a signal Qsp2Connected to the input of the half-bridge driving circuit 502 together with the other output signal QS1 of the PWM generating module 415 in fig. 4, the two output signals Q of the half-bridge driving circuit 502g1And Qg2Are respectively provided withThe main switch tube Q1 and the clamp switch tube Q2 are used for driving the active clamp flyback converter.
Referring to fig. 6, the invention applies to the information v of the drain-source voltage of the main switching tube Q1dspIntroduced into the driving circuit by the second analog comparator 500, i.e. only when v isdspVoltage below threshold voltage vth1When the comparator is turned over to output high level, the driving signal Qg2The Q1 can be driven to be turned on, thus ensuring the drain-source voltage V of the main switch tube Q1 before being turned ondsQ1Having dropped to a lower potential to reliably achieve ZVS turn-on, it should be noted that the precondition for the normal operation of the driving and control circuit shown in fig. 6 is to reasonably control the turn-on time of the clamping switch Q2, and to ensure sufficient reverse exciting current to drain the parasitic capacitance of the main switch Q1 in the dead time. Adjustment of the on-time of the clamp switching tube Q2 depends on the second term of equation (3), i.e., T21＝dTzSaid dTzFurther obtained by the pulse width extraction module 413 and the pulse width closed-loop adjustment module 414 in fig. 5.
Referring to fig. 7, a schematic block diagram of the pulse width extraction module 413 and the pulse width closed-loop adjustment module 414 of fig. 5 is shown, wherein the drain-source voltage V of the main switch Q1dsQ1Signal v after voltage division and samplingdspConnected to the positive terminal of the first analog comparator 600, threshold vth2Connected to the negative terminal of a first analog comparator 600, which outputs a signal vplsConnected to the pulse width capture module for obtaining vplsHigh level duration Tps，TpsSubtracting T by a subtractor2Time-derived characteristic time length TpsfSaid T ispsfThe time is the time length from T2 to T3 in fig. 2B to 2C, and represents the magnitude of the transformer reverse excitation current at the turn-off time of the clamping switch tube Q2 of the converter, and the larger the reverse excitation current is, the larger the T ispsfThe smaller and vice versa. Further, the transformer reverse excitation current determines whether the parasitic capacitance of the main switch tube Q1 of the flyback converter can be reliably discharged within the dead time, and further determines the reliable ZVS switching-on of the main switch Q1. Thus, control TpsfThe Q1 can be realized in a reasonable time lengthBy ZVS. As shown in FIG. 7, the TpsfTime and reference time TrefSubtracting to obtain a difference value TerSaid difference TerThe adjustment value dT of the conduction time of a clamping switch tube Q2 of the active clamping flyback converter can be obtained through the PI regulator modulez. The invention applies to the characteristic time T by a PI regulatorpsfTime control at desired reference TrefIn addition, the control of the reverse excitation current of the transformer of the flyback converter is realized, and the reliable ZVS of the main switching tube Q1 is further realized. It is to be noted that the solution of the present invention application is independent of the specific input voltage and converter load conditions by adjusting the desired reference value TrefZVS of the active clamping flyback converter can be adaptively achieved, and the device has the excellent characteristic of wide application range and convenience in implementation. Reference value T of the characteristic timerefThe switching period is determined according to the input and output conditions of the specific converter, the parasitic capacitance of the switching tube of the converter, the transformer excitation inductance value and other information, and is usually 1% -3% of the switching period.
To further illustrate the effect of the control method on improving efficiency, according to the embodiment of the present invention, a dual-clamp ZVS buck-boost converter is built, as shown in fig. 8. Under the conditions of 36V input voltage, 5V output voltage and 30V clamping capacitor voltage, the steady state waveform of the converter is measured, and as shown in fig. 9, it can be seen that the embodiment of the invention can effectively and accurately control the reverse excitation current of the transformer of the flyback converter, thereby realizing the self-adaptive ZVS (zero voltage switching) opening of the converter.
The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above-mentioned embodiments, and all technical solutions belonging to the idea of the present invention belong to the protection scope of the present invention. It should be noted that modifications and embellishments within the scope of the invention may be made by those skilled in the art without departing from the principle of the invention.

Claims (10)

1. A ZVS adaptive control method for an active clamp class converter, the method comprising the steps of:
step 1Collecting input voltage v of active clamp type converter topologyinsOutput voltage vosAnd the drain-source voltage v of the main switch tube Q1dsp；
Step 2, respectively obtaining the conduction time values T of the main switch tube Q1 and the clamping switch tube Q2 according to the sampling values in the step 11And T2；
Step 3, according to the conduction time value T1And T2Acquiring driving pulses QS1 and QS2 of a main switching tube Q1 and a clamping switching tube Q2;
step 4, drain-source electrode voltage vdspAnd the driving pulse is subjected to logic operation and driving capacity amplification to generate a power driving signal Qg1And Qg2The main switch tube Q1 and the clamping switch tube Q2 are respectively driven, and the ZVS operation of the converter is realized.
2. The adaptive ZVS control method for active clamp converter according to claim 1, wherein step 2 is based on the sampling value of step 1 to obtain the conduction time T of the main switch Q11The specific process comprises the following steps:
step 21-1, input voltage vinsOutput voltage vosThe sampling value carries out closed-loop regulation on the output voltage of the converter through a proportional-integral regulator;
step 21-2, based on the output value v of the proportional-integral regulatorerObtaining the conduction time T of the main switch tube Q11。
3. The adaptive ZVS control method for active clamp converter according to claim 1, wherein step 2 is based on the sampling value of step 1 to obtain the conduction time T of clamp switch Q22The specific process comprises the following steps:
step 22-1, the conduction time T of the main switch tube Q11Obtaining the conduction time T of the clamping switch tube Q2 through volt-second balance20；
Step 22-2, drain-source voltage v of main switch tube Q1dspObtaining v via a comparatorplsA signal;
step 22-3, acquiring v by pulse width captureplsDuration of low level of signal Tps；
Step 22-4, low level duration TpsMinus the conduction time T of the last switching period clamping switching tube Q22Obtaining a characteristic time value T for identifying the ZVS characteristic of the main switching tube Q1psf；
Step 22-5, for the characteristic time value TpsfPerforming proportional integral closed-loop regulation to obtain a switching time adjustment value dT of the clamping switching tube Q2z；
Step 22-6, adjusting the switch time to a value dTzIs superimposed on T20Obtaining the final conduction time value T of the clamping switch tube Q22。
4. The ZVS adaptive control method for active clamp converter according to claim 3, wherein step 4 is performed on the drain-source voltage vdspAnd the driving pulse is subjected to logic operation and driving capacity amplification to generate a power driving signal Qg1And Qg2The specific process comprises the following steps:
step 4-1, drain-source voltage v of the main switch tube Q1dspObtaining Q via a comparatorspA signal;
step 4-2, said QspThe signal and QS2 signal are passed through a two-input AND gate to get Qsp2A signal;
step 4-3, said Qsp2The signal and QS1 signal output Q after passing through a half-bridge driving circuitg1And Qg2The two signals respectively drive the main switch tube Q1 and the clamping switch tube Q2.
5. ZVS adaptive control circuit of active clamp class converter based on the method of any of claims 1 to 4, characterized in that the circuit comprises: the circuit comprises an active clamping flyback converter (400), a digital controller (410), an isolation sampling circuit (401), a first resistance voltage division sampling circuit (402), a second resistance voltage division sampling circuit (404) and a driving and control circuit (403); the main power circuit of the active clamp flyback converter (400) comprises a main switching tube Q1 and a clamp switching tube Q2;
the active clamp flyback converter (400) outputs a voltage VoConverted into an analog sampling signal v via an isolated sampling circuit (401)osConnected to a digital controller (410) for closed loop control of the flyback converter; an input voltage source V of the active clamp flyback converter (400)inConverted into an analog sampling signal v via a first resistive divider sampling circuit (402)insThe digital controller (410) is connected to calculate the on-time parameters of a main switching tube Q1 and a clamping switching tube Q2 of the flyback converter; the drain-source voltage V of the main switch tube Q1 of the active clamp flyback converter (400)dsQ1Converted into an analog sampling signal v via a second resistive divider sampling circuit (404)dspThe converter is connected to a digital controller (410) and used for realizing self-adaptive ZVS control of a flyback converter main switching tube Q1; the digital controller (410) outputting drive pulses QS1 and QS 2; the driving pulses QS1 and QS2 and the output signal v of the second resistance voltage division sampling circuit (404)dspIs connected to a drive and control circuit (403), the drive and control circuit (403) outputting a drive signal Qg1And Qg2The main switch tube Q1 and the clamping switch tube Q2 of the flyback converter are respectively driven.
6. The ZVS adaptive control circuit of active-clamp class converter according to claim 5, characterized in that said digital controller (410) comprises output voltage closed-loop regulation module (411), Q1 and Q2 switch tube on-time parameter calculation module (412), pulse width extraction module (413), pulse width closed-loop regulation module (414) and PWM generation module (415);
sampling value v of output voltageosIs connected to an output voltage closed-loop regulation module (411) for closed-loop controlling the output voltage of the active clamp flyback converter for proportional-integral regulator operation, i.e. ver＝(kp+ki/s)×(Voref-vos) In which V isorefRepresenting the converter output voltage reference value, kpAnd kiProportional and integral coefficient constants, respectively; drain-source voltage vdspVia a pulse width extraction module (413) The pulse width closed-loop regulating module (414) outputs a pulse width regulating output value dTzAs a switching time adjustment value of the clamp switching tube Q2; regulator output value verSampling value v of input voltageinsSampling value v of output voltageosAnd pulse width modulation output value dTzThe Q1 and Q2 switching tube on-time parameter calculation modules (412) are connected to and are used for calculating the on-time parameters T of the main switching tube Q1 and the clamping switching tube Q21And T2(ii) a The time parameter T of opening1And T2Drive pulses QS1 and QS2 for the main switch transistor Q1 and the clamp switch transistor Q2 are generated via a PWM generation module (415).
7. The ZVS adaptive control circuit for active clamp class converter according to claim 6, wherein the on time parameter T of the main switch Q11The calculation formula of (2) is as follows:
Figure FDA0003340380040000031
8. the ZVS adaptive control circuit for active clamp class converter according to claim 7, wherein on time parameter T of said clamp switch Q22The calculation formula of (2) is as follows:
Figure FDA0003340380040000032
in the formula, n represents the primary and secondary side turn ratio of the transformer of the flyback converter.
9. The ZVS adaptive control circuit of active clamp class converter according to claim 6, wherein said pulse width extraction module (413), pulse width closed loop adjustment module (414) comprises a first analog comparator (600), pulse width capture module (601) and PI adjuster (602);
drain-source voltage vdspThreshold value vth2Connected to the positive and negative terminals, respectively, of a first analog comparator (600), the output signal v of the first analog comparator (600)plsConnected to a pulse width capture module (601) for acquiring vplsHigh level duration Tps，TpsSubtracting the time T by a subtractor2Obtaining a characteristic time length Tpsf，TpsfAnd a reference time TrefObtaining a difference value T by a subtracterer，TerThe switching time adjustment value dT of the clamping switching tube Q2 is output through a PI regulator (602)z。
10. ZVS adaptive control circuit of active clamp class converter according to claim 6, characterized in that the driving and control circuit (403) comprises a second analog comparator (500), a dual input AND gate (501) and a half bridge driving circuit (502);
drain-source voltage vdspComparator reference vth1Connected to the negative and positive terminals, respectively, of a second analog comparator (500), the output signal Q of the second analog comparator (500)spQS2 output by the PWM generating module (415) are respectively connected to two input ends of a two-input AND gate (501), and an output signal Q of the two-input AND gate (501)sp2And QS1 output by the PWM generation module (415) is connected to a half-bridge driving circuit (502) which outputs two driving signals Qg1And Qg2The main switch tube Q1 and the clamping switch tube Q2 of the flyback converter are respectively driven.
CN202111306671.7A 2021-11-05 2021-11-05 ZVS self-adaptive control method and circuit of active clamp converter Pending CN113872450A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202111306671.7A CN113872450A (en) 2021-11-05 2021-11-05 ZVS self-adaptive control method and circuit of active clamp converter

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202111306671.7A CN113872450A (en) 2021-11-05 2021-11-05 ZVS self-adaptive control method and circuit of active clamp converter

Publications (1)

Publication Number Publication Date
CN113872450A true CN113872450A (en) 2021-12-31

Family

ID=78987286

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202111306671.7A Pending CN113872450A (en) 2021-11-05 2021-11-05 ZVS self-adaptive control method and circuit of active clamp converter

Country Status (1)

Country Link
CN (1) CN113872450A (en)

Similar Documents

Publication Publication Date Title
US10333418B2 (en) Control device and control method
US8829865B2 (en) Power factor correction efficiency improvement circuit, a converter employing the circuit and a method of manufacturing a converter
US6469913B2 (en) Switching power supply device having series capacitance
US8749996B2 (en) Switching power supply apparatus
CN113595398B (en) Control device and control method
CN110661427B (en) Digital control device based on gallium nitride device active clamping flyback AC-DC converter
CN112054659A (en) Zero-voltage-conduction flyback circuit and control method and control circuit thereof
CN112117905A (en) Control system and method of active clamp flyback converter
CN111585440B (en) Control system and method of active clamp flyback converter
CN110460239B (en) Active clamp flyback converter
CN112271926B (en) Prediction current mode control method of GaN-based active clamp flyback converter
CN112564489B (en) Mode control method of switch converter and switch converter
US20240007009A1 (en) Dynamic Intra-Pulse-Sequence Switch Transition-Time Controller
CN113131747A (en) Flyback converter control method and control device thereof
CN110445387B (en) Topological structure and control method of formation and grading power supply
CN106100392B (en) Eliminate working frequency ripple wave high efficiency high power factor AC/DC power circuits and its method of supplying power to and control method
CN111585441B (en) Control system and method for primary side regulation active clamping flyback converter
CN115102368A (en) Control circuit of resonant circuit and control method thereof
CN114793069A (en) Burst power control method and circuit of clamp asymmetric half-bridge flyback converter
CN210405095U (en) Detection circuit, switch control circuit and flyback conversion circuit
CN107612030B (en) Photovoltaic converter with current quasi-critical continuous and device soft switch
CN116545266A (en) Switching power supply and computing device
CN113708631B (en) Flyback converter and control method thereof
US12081109B2 (en) Switching converter and control circuit thereof
CN113708633B (en) Flyback converter control method, flyback converter and control device

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination