CN109286307A - A kind of Forward- flyback power factor correcting - Google Patents

A kind of Forward- flyback power factor correcting Download PDF

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Publication number
CN109286307A
CN109286307A CN201710595506.5A CN201710595506A CN109286307A CN 109286307 A CN109286307 A CN 109286307A CN 201710595506 A CN201710595506 A CN 201710595506A CN 109286307 A CN109286307 A CN 109286307A
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diode
circuit
capacitor
anode
connection
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云珂
韩业华
黄轶群
朱莲莉
顾伟
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Nanjing University of Science and Technology
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Nanjing University of Science and Technology
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Priority to CN201710595506.5A priority Critical patent/CN109286307A/en
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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
    • H02M1/42—Circuits or arrangements for compensating for or adjusting power factor in converters or inverters
    • H02M1/4208—Arrangements for improving power factor of AC input
    • H02M1/4241—Arrangements for improving power factor of AC input using a resonant converter
    • 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
    • H02M1/14—Arrangements for reducing ripples from dc input or output
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
    • H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
    • H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
    • H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
    • H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/33569—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements
    • H02M3/33576—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 having at least one active switching element at the secondary side of an isolation transformer
    • 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

Abstract

The invention discloses a kind of Forward- flyback power factor correctings, which is characterized in that including AC alternating current source, rectifier circuit, Buck-Boost circuit, DC/DC translation circuit and control circuit；Wherein, the output end of the AC alternating current source and the input terminal of rectifier circuit connect, the output end of rectifier circuit is connect with the input terminal of Buck-Boost circuit, the output end of Buck-Boost circuit is connect with the input terminal of DC/DC translation circuit, DC/DC translation circuit outputs signal to control circuit, and control circuit controls Buck-Boost circuit according to the output signal of DC/DC translation circuit.The present invention increases output power, the high frequency ripple rate and low-frequency ripple rate of output voltage are smaller by increasing mid-stage voltage ripple.

Description

A kind of Forward- flyback power factor correcting
Technical field
The present invention relates to converters technical field, especially a kind of Forward- flyback power factor correcting.
Background technique
In global electric structure, illumination power consumption accounts for the 19% of whole world total power consumption, and in this number of China Also it is up to 12%, it may be seen that electric consumption on lighting amount occupies very big ratio in entire power structure.As LED is quickly sent out Exhibition, the development of LED drive power are also essential.Due to typically containing electrolytic capacitor in traditional LED drive power, and it is electrolysed electricity The service life of appearance is far smaller than the service life of LED body, so that LED drive power can not be matched with the service life of LED body, causes LED The frequent replacement of driving power, and electrolytic capacitor volume is larger, limits the power density of switch converters.In order to remove Electrolytic capacitor in LED drive power, there has been proposed propose the driving circuit topology of no electrolytic capacitor.
Traditional single stage type circuit without non-electrolytic capacitance topology is simple, only needs a Voltage loop with regard to the control of achievable control loop The DC/DC grade of system, circuit topology provides feedback access, effective solution using Buck-Boost circuit for transformer leakage inductance The due to voltage spikes problem at switching tube both ends, LED driving is simple with circuit structure, control requires low and leakage inductance electric current that can return The advantages that being fed to input terminal.But the output voltage current ripples of converter input the big of ripple dependent on intergrade capacitor Small, in the case where limiting intergrade capacitor's capacity, output voltage current ripples only depend on output capacitance and are filtered, and lead Cause its output power too big.Therefore the circuit topology is only applicable to very low power occasion, is not suitable for being applied to output The higher occasion of the quality requirement of voltage, this severely limits the practical applications of this quasi-converter.
Based on the circuit of traditional no electrolytic capacitor, the invention proposes a kind of novel single-stage no electrolytic capacitor Buck- Boost Forward- flyback pfc converter.It inherits the advantages of leakage inductance feedback circuit in traditional circuit, eliminates prime power switch The due to voltage spikes at pipe both ends, and PFC grades and DC/DC grades have the transmitting that intergrade capacitor carries out energy, transformer work In the mode of Forward- flyback, magnetic core utilization rate is higher, this circuit topology realizes that the principle of no electrolytic capacitor is consistent with conventional topologies. But since DC/DC grades of afterflow inductance and filter capacitor is filtered jointly, by increasing mid-stage voltage ripple, increase Output power, the high frequency ripple rate and low-frequency ripple rate of output voltage are smaller.
Summary of the invention
The purpose of the present invention is to provide a kind of Forward- flyback power factor correctings.
Realize technical solution of the invention are as follows: a kind of Forward- flyback power factor correcting, including it is AC alternating current source, whole Flow bridge circuit, Buck-Boost circuit, DC/DC translation circuit and control circuit；Wherein:
The input terminal of the output end of the AC alternating current source and rectifier circuit connects, the output end of rectifier circuit with The input terminal of Buck-Boost circuit connects, and the output end of Buck-Boost circuit is connect with the input terminal of DC/DC translation circuit, DC/DC translation circuit outputs signal to control circuit, and control circuit controls Buck- according to the output signal of DC/DC translation circuit Boost circuit.
Further, the rectifier circuit includes the first normal silicon diode VD1, the second normal silicon diode VD2, Three normal silicon diode VD3, the 4th normal silicon diode VD4And input high-frequency filter capacitor Cin；The one of the AC alternating current source End and first diode VD1Anode connection, the other end of the AC alternating current source and the second diode VD2Anode connection；It is described First diode VD1Anode and third diode VD3Cathode be connected, the second diode VD2Anode and the four or two pole Pipe VD4Cathode be connected, the first diode VD1Cathode and the second diode VD2Cathode connection, the third Diode VD3Anode and the 4th diode VD4Anode connection；The input high-frequency filter capacitor CinOne end simultaneously With first diode VD1Cathode and the second diode VD2Cathode be connected, the input high-frequency filter capacitor CinIt is another One end simultaneously with third diode VD3Anode and the 4th diode VD4Anode connection.
Further, the Buck-Boost circuit includes first diode DS1, energy storage inductor La, first switch tube S1、 First capacitor C1, the second diode DS2And third diode DR；The first diode DS1Cathode and energy storage inductor La's One end connection, the energy storage inductor LaThe other end and first switch tube S1Drain electrode and first capacitor C1One end connection；Institute State first capacitor C1The other end and the second diode DS2Cathode and third diode DRAnode connection, the described 3rd 2 Pole pipe DRCathode and the first diode DS1Anode connection；
The first diode DS1Anode and the first switch tube S1Source electrode as Buck-Boost circuit Input terminal is connect with the output end of the rectifier circuit；
The second diode DS2Anode and the first switch tube S1Source electrode as Buck-Boost circuit Output end is connect with the input terminal of DC/DC circuit.
Further, the DC/DC translation circuit includes transformer T, the second capacitor C2, second switch S2, the four or two pole Pipe DS3, the 5th diode Do, output capacitance CoAnd outputting inductance Lo；The output end of the transformer T and the second capacitor C2One End and the 4th diode DS3Anode connection, the second capacitor C2The other end and second switch S2Drain electrode, it is described Second switch S2Source electrode simultaneously with outputting inductance LoOne end, the 4th diode DS3Cathode and the 5th diode Do's Anode connection, the 5th diode DoCathode and the second switch S2Drain electrode connection, the outputting inductance LoIt is another One end and output capacitance CoOne end connection, the output capacitance CoThe other end and the 4th diode DS3Anode connection, institute State output capacitance CoBoth ends simultaneously with load RLBoth ends connection.
The present invention has following positive technical advantage: 1) present invention inherits the excellent of leakage inductance feedback circuit in traditional circuit Point, and eliminate the due to voltage spikes at prime power switch tube both ends；2) circuit of power factor correction and DC/DC circuit in the present invention There is intermediate capacitance and carry out energy transmission, transformer works in the mode of Forward- flyback, and magnetic core utilization rate is high；3) present invention is used for In LED illumination power-supply system, the thin-film capacitor of longer life expectancy can be used, improve the bulk life time of LED illumination System；4) of the invention By increasing mid-stage voltage ripple, increase output power, the high frequency ripple rate and low-frequency ripple rate of output voltage compared with It is small.
High frequency output performance and low frequency output performance based on the positive and negative excitation circuit of the above advantage single-stage Buck-Boost have Very big raising.
Detailed description of the invention
Fig. 1 is the structural block diagram of the embodiment of the present invention.
Fig. 2 is the main circuit and control circuit topological diagram of the embodiment of the present invention.
Fig. 3 is the novel B uck-Boost forward converter power flow direction figure of the embodiment of the present invention.
Fig. 4 is that the first switch tube S1 and second switch S2 of the embodiment of the present invention simultaneously turn on equivalent operation mode.
Fig. 5 is that the first switch tube S1 and second switch S2 of the embodiment of the present invention simultaneously turn off equivalent operation mode.
Fig. 6 is that the first switch tube S1 and second switch S2 of the embodiment of the present invention discontinuously turn off equivalent operation mode.
Fig. 7 is the outputting inductance L of the embodiment of the present inventionoWork is in DCM mode equivalent operation mode.
Fig. 8 is the outputting inductance L of the embodiment of the present inventionoWork is in CCM mode equivalent operation mode.
Specific embodiment
In conjunction with Fig. 1, a kind of Forward- flyback power factor correcting of the invention, including AC alternating current source, rectifier circuit, Buck-Boost circuit, DC/DC translation circuit and control circuit；Wherein, the output end of the AC alternating current source and rectifier bridge electricity The input terminal on road connects, and the output end of rectifier circuit is connect with the input terminal of Buck-Boost circuit, Buck-Boost circuit Output end connect with the input terminal of DC/DC translation circuit, DC/DC translation circuit outputs signal to control circuit, control circuit Buck-Boost circuit is controlled according to the output signal of DC/DC translation circuit.
Further, the rectifier circuit includes the first normal silicon diode D1, the second normal silicon diode D2, third Normal silicon diode D3, the 4th normal silicon diode D4And input high-frequency filter capacitor Cin；One end of the AC alternating current source with First diode D1Anode connection, the other end of the AC alternating current source and the second diode D2Anode connection；Described 1st Pole pipe D1Anode and third diode D3Cathode be connected, the second diode D2Anode and the 4th diode D4Yin Extremely it is connected, the first diode D1Cathode and the second diode D2Cathode connection, the third diode D3Sun Pole and the 4th diode D4Anode connection；The input high-frequency filter capacitor CinOne end simultaneously with first diode D1 Cathode and the second diode D2Cathode be connected, the input high-frequency filter capacitor CinThe other end simultaneously with the three or two Pole pipe D3Anode and the 4th diode D4Anode connection.
Further, the Buck-Boost circuit includes first diode DS1, energy storage inductor La, first switch tube S1、 First capacitor C1, the second diode DS2And third diode DR；The first diode DS1Cathode and energy storage inductor La's One end connection, the energy storage inductor LaThe other end and first switch tube S1Drain electrode and first capacitor C1One end connection；Institute State first capacitor C1The other end and the second diode DS2Cathode and third diode DRAnode connection, the described 3rd 2 Pole pipe DRCathode and the first diode DS1Anode connection；
The first diode DS1Anode and the first switch tube S1Source electrode as Buck-Boost circuit Input terminal is connect with the output end of the rectifier circuit；
The second diode DS2Anode and the first switch tube S1Source electrode as Buck-Boost circuit Output end is connect with the input terminal of DC/DC circuit.
Further, the DC/DC translation circuit includes transformer T, the second capacitor C2, second switch S2, the four or two pole Pipe DS3, the 5th diode Do, output capacitance CoAnd outputting inductance Lo；The output end of the transformer T and the second capacitor C2One End and the 4th diode DS3Anode connection, the second capacitor C2The other end and second switch S2Drain electrode, it is described Second switch S2Source electrode simultaneously with outputting inductance LoOne end, the 4th diode DS3Cathode and the 5th diode Do's Anode connection, the 5th diode DoCathode and the second switch S2Drain electrode connection, the outputting inductance LoIt is another One end and output capacitance CoOne end connection, the output capacitance CoThe other end and the 4th diode DS3Anode connection, institute State output capacitance CoBoth ends simultaneously with load RLBoth ends connection.
In the following, a kind of Forward- flyback power factor correcting proposed to invention is made a concrete analysis of:
1, the working principle of the present apparatus are as follows:
First switch tube S1When conducting, the work of transformer T pair side is in normal shock mode, and the flow direction of electric current is such as the 1. institute in Fig. 3 Show, the exciting current in transformer T increases, and transformer T is secondary side charging.First switch tube S1When disconnection, transformer T pair side electricity It flows reversely, transformer T work is in flyback mode, and for the flow direction of electric current as 2. shown in Fig. 3, flyback converter is the second capacitor C2With Load is charged, and secondary side exciting current is decreased to zero.After flyback converter drops to zero, afterflow inductance continues as load supplying, As the electric current in Fig. 3 3. shown in.First switch tube S1Two kinds of functions are realized herein: realizing electric current two-way flow function；Anti- After sharp electric current drops to zero, prevent because of the second capacitor C2The effect of both end voltage, outputting inductance LoOn electric current inflow transformer T, so that transformer T work is in DCM mode.
2, main circuit topological structure
As shown in connection with fig. 2, main components in main circuit topology figure: main circuit topology is Boost circuit, including AC exchange Source (3kVA pressure regulator), the first normal silicon diode VD1, the second normal silicon diode VD2, third normal silicon diode VD3, Four normal silicon diode VD4The uncontrollable rectifier bridge circuit (KBL410) of composition inputs high-frequency filter capacitor Cin(thin-film capacitor, 400V/0.1 μ F), energy storage inductor La(PQ FERRITE CORE, 330 μ H), first capacitor C1, the second capacitor C2(thin-film capacitor, 400V/10 μ F), output filter capacitor Co(CBB electric capacity, 450V/20 μ F), filter inductance Lo(1.2mH), two switch mosfets Pipe first switch tube S1With second switch S2(SPP20N60C3), transformer T, pure resistor load RL(load box).
3, control circuit topological structure
As shown in connection with fig. 2, control circuit is controlled using Voltage loop, and circuit output end passes through sampling resistor RsTo load current It is sampled, obtained sampled voltage is compared to obtain the error signal for needing to adjust, error signal and three with reference voltage Angle wave signal is compared, and obtains the PWM output pulse of control circuit, and pwm pulse generates switching tube institute after opto-coupler chip The driving signal needed, driving switch pipe work normally.
4, converter principle Analysis
A kind of Forward- flyback power factor correcting of the invention not only joined positive and negative stimulation type DC/DC circuit (4), also exist Buck-Boost circuit joined first diode D in (3)S1With the second diode DS2, first diode DS1For interrupting energy storage Inductance LaDue to first capacitor C during interrupted1Presence and the low frequency circuit that generates.Second diode DS2It prevents in leakage inductance electricity Flow iLbkEnergy storage inductor L after feedbackaIt discharges during electric discharge transformer.In order to simplify theory analysis, circuit is opened up Flutter proposition it is assumed hereinafter that:
(1) in addition to transformer T is there are other than leakage inductance, other elements are preferably, parasitic parameter to be not present, therefore can manage Solving it, there is no loss, efficiency 100%.
(2)VrecIndicate the voltage after rectifier bridge is rectified, expression formula Vrec=Vm| sin (ω t) |, VmIt is exchange The peak value of input voltage, ω are electrical network angular frequency, the π of ω=2 f.
(3) because switching frequency is much larger than the angular frequency of power grid, therefore it can be considered that power grid input voltage is in one cycle Steady state value, i.e. input capacitance CinVoltage swing above is constant.
(4) in analysis below, it is assumed that first capacitor C1With output capacitance CoCapacitance is sufficiently large, i.e., in intergrade capacitor It is for steady state value with both ends of filter capacitor voltage.
With transformer T exciting current whether continuously to distinguish, mainly exciting current is continuously carried out with interrupted two states Analysis, the i.e. interrupted mode of exciting current (DCM mode) and the continuous mode of exciting current (CCM mode).
In conjunction with as shown in figure 4, converter is divided into four operation modes in a switch periods:
1 [t of mode0, t1]: first switch tube S1, second switch S2It being both turned on, transformer T works under normal shock mode, As shown in connection with fig. 4, there are three types of circuits under such mode: (1) inductance heart charge circuit, the circuit is by input high-frequency filter capacitor Cin, the 5th diode D0, energy storage inductor La, first switch tube S1Composition, in VrecUnder the action of, inductive current iLaLinear increase； (2) magnetizing inductance LbCharge circuit, the circuit is by first capacitor C1, first switch tube S1, transformer T, side inductance composition, first Capacitor C1For primary side induction charging, magnetizing inductance LbOn electric current linear increase；(3) secondary side normal shock mode circuit, the 5th diode DoIt disconnects, secondary side induced voltage and the second capacitor C2Voltage be overlapped the load that is negative jointly and be powered, iLoLinear increase.Mould State 1 is d1TsStage, d1For the duty ratio of first switch tube, TsFor switch periods.
2 [t of mode1, t2]: first switch tube S1, second switch S2It disconnects, as shown in connection with fig. 5, has three under the stage Circuit: (1) energy storage inductor LaDischarge loop, the circuit is by energy storage inductor La, first capacitor C1, the 5th diode Do, the one or two Pole pipe VD1Composition, energy storage inductor LaPass through the 5th diode DoWith first diode VD1To first capacitor C1It charges, iLaLine Property decline；(2) leakage inductance LbkDischarge loop, the circuit is by transformer primary side inductance, input high-frequency filter capacitor Cin, second Diode DS2With third diode DRComposition, leakage field energy pass through the second diode DS2Feed back output end, leakage inductance and input High-frequency filter capacitor CinResonance, i occursLbkIt decreases nonlinearly, in t2Moment, leakage inductance energy discharge off；(3) secondary inductance Flyback circuit, the circuit is by secondary inductance, the 4th diode DS3, second switch S2, the second capacitor C2It forms, in transformer T Flyback energy be the second capacitor C2It charges, flyback converter iLbsDecline；(4) outputting inductance LoContinuous current circuit, outputting inductance LoAfterflow, i are carried out to loadLoIt is linear to reduce.Due to second switch S2There are parasitic capacitance, iLbsDirection be mutated so that Second switch S2The both ends peak voltage very short there are a time.Here resonance time:
In order to guarantee within the duty cycle, leakage inductance energy can be fed back to input terminal, overall resonance time t completelyrec- fixed It is less than switching tube turn-off time.
3 [t of mode2, t3]: in magnetizing inductance work in DCM mode, first switch tube S1, second switch S2After teasel root It opens, as shown in connection with fig. 6, leakage inductance discharge off, electric current i similar to 2 operating mode of modeLaWith iLbsContinue to decline, electricity Flow iLaWith iLbsIt is any to be reduced to zero in advance, the operation mode of whole circuit is not influenced, here t3I.e. refer to two kinds of electric currents it is last under At the time of dropping to zero.Mode 2 and mode 3 collectively constitute d2TsStage, d2At the time of dropping to zero for transformer secondary flyback converter Duty ratio corresponding to a time cycle.
In magnetizing inductance work in CCM mode, first switch tube S1, second switch S2Continue to disconnect, at this time leakage inductance Discharge off, that different from DCM state is i hereLaDrop to zero, iLbsContinue to decline, but is not reduced to zero.
Mode 4-1 [t3, t4]: as shown in connection with fig. 7, first switch tube S1, second switch S2Continue to disconnect, and iLaWith iLbsHaving discharged terminates, at this time in first switch tube S1The voltage at both ends is equal to first capacitor C1Voltage.Due to excitation electricity Inducing current is gradually reduced to 0, in the equivalent magnetizing inductance L in this period pair sidebs, the second capacitor C2With second switch S2Occur humorous Vibration, second switch S2On voltage by occur shake voltage, final second switch S2The voltage at both ends and the second capacitor C2Two The voltage swing at end is equal.Outputting inductance inductance LoIt continues as load and carries out afterflow, outputting inductance LoWork is in DCM mode, t4When Carving entire switch periods terminates.
Mode 4-2 [t3, t4]: as shown in connection with fig. 8, the mode to be worked at this time in CCM state is different from DCM, in next work Before making period arriving, flyback converter iLbsContinue decline and no arrival zero, in t4Next duty cycle at moment arrives, this When second switch S2There is reversed flyback converter, the second switch S within this duty cycle2It realizes no-voltage to be connected, one Determine to improve efficiency in degree, here d2It is equal to 1-d1。
5, power factor and duty ratio d1Calculating
Exchange end input voltage is set as Vin=VmSin (ω t), wherein ω is the angular frequency of input voltage, VmFor input electricity The peak value of pressure.The input voltage V after rectifier bridgerec=Vm|sin(ωt)|.Circuit works in DCM state, inductance LaPeak value Electric current iLa_pAre as follows:
By the operation mode of circuit it is found that the average value of input current are as follows:
By formula (4) it is found that under DCM operation mode, complete SIN function relationship is presented in input current and voltage.
Within a duty cycle, input power are as follows:
In formula, fsFor switching frequency.
Control circuit carries out quick voltage adjusting, and duty ratio can be approximately:
The converter is able to achieve automatic power factor correction and is able to maintain the premise of high power factor, is converter function The input inductance L of rate factor correcting circuitaDCM mode is always worked in, in the entire converter duty cycle, duty ratio is kept not Become, then there is the following formula must satisfy:
Vc1×(1-d1) > Vmd1 (7)
I.e.
6, transformer magnetizing current continuation degree k
Converter secondary inductance flyback converter still works in continuous state in on-off state regardless of work, the second capacitor C2 On voltage and first capacitor C1On voltage all meet following relationship:
Wherein, k represents the continuation degree that transformer works in intermittent mode, when the value range of k is 0 < k≤1, k=1, Work is represented in exciting current continuous mode, the expression formula of k are as follows:
Wherein, d2Corresponding duty ratio at the time of dropping to zero for transformer secondary flyback converter, when transformer work exists D when CCM mode2=1-d1。

Claims (4)

1. a kind of Forward- flyback power factor correcting, which is characterized in that including AC alternating current source [1], rectifier circuit [2], Buck-Boost circuit [3], DC/DC translation circuit [4] and control circuit [5]；Wherein, the output of the AC alternating current source [1] End is connect with the input terminal of rectifier circuit [2], the output end of rectifier circuit [2] and the input of Buck-Boost circuit [3] End connection, the output end of Buck-Boost circuit [3] are connect with the input terminal of DC/DC translation circuit [4], DC/DC translation circuit [4] it outputs signal to control circuit [5], control circuit [5] controls Buck- according to the output signal of DC/DC translation circuit [4] Boost circuit [3].
2. Forward- flyback power factor correcting according to claim 1, it is characterised in that: the rectifier circuit [2] Including the first normal silicon diode [VD1], the second normal silicon diode [VD2], third normal silicon diode [VD3], it is the 4th common Silicon diode [VD4] and input high-frequency filter capacitor [Cin]；One end of the AC alternating current source [1] and first diode [VD1] Anode connection, the other end and the second diode [VD of the AC alternating current source [1]2] anode connection；The first diode [VD1] anode and third diode [VD3] cathode be connected, the second diode [VD2] anode and the 4th diode [VD4] cathode be connected, the first diode [VD1] cathode and the second diode [VD2] cathode connection, it is described Third diode [VD3] anode and the 4th diode [VD4] anode connection；Input high-frequency filter capacitor [the Cin] One end simultaneously with first diode [VD1] cathode and the second diode [VD2] cathode be connected, the input high frequency Filter capacitor [Cin] the other end simultaneously with third diode [VD3] anode and the 4th diode [VD4] anode connection.
3. Forward- flyback power factor correcting according to claim 1, which is characterized in that the Buck-Boost circuit It [3] include first diode [DS1], energy storage inductor [La], first switch tube [S1], first capacitor [C1], the second diode [DS2] And third diode [DR]；First diode [the DS1] cathode and energy storage inductor [La] one end connection, the energy storage Inductance [La] the other end and first switch tube [S1] drain electrode and first capacitor [C1] one end connection；The first capacitor [C1] the other end and the second diode [DS2] cathode and third diode [DR] anode connection, the third diode [DR] cathode and the first diode [DS1] anode connection；
First diode [the DS1] anode and the first switch tube [S1] source electrode as Buck-Boost circuit [3] Input terminal connect with the output end of the rectifier circuit [2]；
Second diode [the DS2] anode and the first switch tube [S1] source electrode as Buck-Boost circuit [3] Output end connect with the input terminal of DC/DC circuit [4].
4. Forward- flyback power factor correcting according to claim 1, which is characterized in that the DC/DC translation circuit It [4] include transformer [T], the second capacitor [C2], second switch [S2], the 4th diode [DS3], the 5th diode [Do], it is defeated Capacitor [C outo] and outputting inductance [Lo]；The output end and the second capacitor [C of the transformer [T]2] one end and the four or two Pole pipe [DS3] anode connection, the second capacitor [C2] the other end and second switch [S2] drain electrode, described second opens Close pipe [S2] source electrode simultaneously with outputting inductance [Lo] one end, the 4th diode [DS3] cathode and the 5th diode [Do] Anode connection, the 5th diode [Do] cathode and the second switch [S2] drain electrode connection, the outputting inductance [Lo] the other end and output capacitance [Co] one end connection, the output capacitance [Co] the other end and the 4th diode [DS3] Anode connection, the output capacitance [Co] both ends simultaneously with load RLBoth ends connection.
CN201710595506.5A 2017-07-20 2017-07-20 A kind of Forward- flyback power factor correcting Pending CN109286307A (en)

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110247555A (en) * 2019-07-09 2019-09-17 上海来远电子科技有限公司 A kind of isolated power supply adapting device of no high-voltage electrolytic capacitor and photo-coupler
CN110855151A (en) * 2019-11-26 2020-02-28 广州金升阳科技有限公司 Positive and negative excitation type switching power supply circuit and control method thereof
CN113708643A (en) * 2021-08-30 2021-11-26 宜宾职业技术学院 Two-path output famous tea picking robot power supply based on current-multiplying capacitor network
CN114665700A (en) * 2022-05-26 2022-06-24 哈尔滨工业大学 Forward and flyback-resonant type single-stage bridgeless isolated PFC converter

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110247555A (en) * 2019-07-09 2019-09-17 上海来远电子科技有限公司 A kind of isolated power supply adapting device of no high-voltage electrolytic capacitor and photo-coupler
CN110247555B (en) * 2019-07-09 2024-02-13 上海来远电子科技有限公司 Isolated power supply adapter device without high-voltage electrolytic capacitor and optical coupler
CN110855151A (en) * 2019-11-26 2020-02-28 广州金升阳科技有限公司 Positive and negative excitation type switching power supply circuit and control method thereof
CN110855151B (en) * 2019-11-26 2020-12-18 广州金升阳科技有限公司 Positive and negative excitation type switching power supply circuit and control method thereof
CN113708643A (en) * 2021-08-30 2021-11-26 宜宾职业技术学院 Two-path output famous tea picking robot power supply based on current-multiplying capacitor network
CN113708643B (en) * 2021-08-30 2023-11-24 宜宾职业技术学院 Two-way output famous tea picking robot power supply based on doubly-charged capacitor network
CN114665700A (en) * 2022-05-26 2022-06-24 哈尔滨工业大学 Forward and flyback-resonant type single-stage bridgeless isolated PFC converter
CN114665700B (en) * 2022-05-26 2022-08-26 哈尔滨工业大学 Forward and flyback-resonant type single-stage bridgeless isolated PFC converter

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Application publication date: 20190129