TW201112597A - Single-stage flyback power factor correction converter - Google Patents

Abstract

A single-stage flyback power factor correction converter, comprises: a power factor correction unit for reducing the low frequency harmonic current generated by input current and reducing the phase difference of input current and input voltage; a soft switching flyback converter, shared internal switching components with the power factor correction unit and coupled with the output terminal of the power factor correction unit, for processing the output voltage from the power factor correction unit; a controller, coupled with the soft switching flyback converter, for adjusting the operations of the soft switching flyback converter so as to allow the energy transformation within such that zero voltage switch or zero current switch can be achieved; and a DC bus capacitor which is coupled with the input terminal of power factor correction unit in series and connected with the soft switching flyback converter in parallel as a internal energy storage capacitor. The objective is to improve the power electronics circuit design for reducing the requirements and constraints of high-rated amount of voltage in relevant components.

Description

201112597 VI. Description of the Invention: [Technical Field of the Invention] A flyback converter, especially a single-stage power factor correction converter. [Prior Art] With the advancement of modern technology and the rapid development of portable electronic products, the performance and various applications of phase-cut converters have received increasing attention. In recent years, the development of the power electronics technology by the side of the towel and the development of nanotechnology, electricity to light and thin, Weiyuan, and the direction of cost reduction, its internal = need to face light and thin, energy saving, improve power and reduce制作成出^参^ A picture 'used on the surface of notebook computers or other electronic products' 'has adopted discontinuous current mode (service) power factor 30 and current mode control circuit 5g) to adjust the output voltage and Circuit (10), and the cost is higher due to 5 different control (four) road system body size, and high cost two-stage tandem structure will be ^ original ^ ship architecture _, volume compared to the traditional converter: = have === Demand by capacitor _. For example, i raises the DC busbar type (B(10), (4) ceramics logistics module with the same system, to improve the power factor. (4) gas isolation, and the adjustment of the transmission, and the H brother's single-stage power factor correction circuit Power 201112597 Two circuits, and in order to improve the power factor, reduce the low-frequency harmonics, waves, usually need a larger output capacitance to extend the Wi-link to eliminate twice the mains frequency chopping. At the same time, single-stage power factor correction switch and DC convergence The discharge capacitor must be able to withstand high withstand voltage. The force rate is small [invention] The purpose of the invention is to provide a single-stage flyback power = correction converter to solve the conventional two-stage series connection The problem of circuit conversion is to achieve a reduction in volume and weight, energy-saving circuit power factor, and the need to reduce the voltage of two thousand white, front-end voltage, to supply a single-stage circuit, a single-stage flyback power factor. ^ 丄 毛 从 从 供 应力 应力 应力 应力 应力 应力 应力 应力 应力 应力 应力 应力 应力 应力 应力 应力 应力 应力 应力 应力 ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; Yi·zhong, from 杳m·^ The low frequency generated by the input current is reduced by the yuan system: all: = #料* is used to input current and input electric dust: tend to be the same skin = lang output electric type 榼 * 丄丄 丄丄 ] ] ] ] ] ] ] ] ] ] ] The device, the part conversion = the DC power of the processing power factor correction unit is positive; the = output is: the flexible switching flyback converter controls the energy conversion between the day and the diode to achieve zero electric motor And zero current cut 201112597 For the purpose, · DC busbar capacitor, is: wheel, and parallel to the flexible switching butterfly converter as two positive, reduce the wheel voltage chopping and increase the maintenance time. According to the present invention, the single-stage returning and turning-over main switch and the auxiliary switch are cut off and turned on, and the loop is controlled, and the loop electric vibration and the amount thereof are used to achieve flexible switching and improve the circuit energy sense wheel. 'With the design of the present invention, the single-stage 钣' is abundance. The low-voltage stress components can be used to achieve high power: port number::::Hold-upW, reducing the characteristics of output voltage chopping. Long, · 隹 为 使 使 使 使 使 使 使 使 使 使 使 使 使 使 使 使 使 使 使Detailed description and: = 2: The formula is for reference and explanation only, and is not used for the second invention: [Embodiment] Power-type single-stage flyback type power axis number correction converter, which is a dream 4 and control The switching transistor gate voltage waveform and = are in phase, and further improve the switching energy loss limit. Reduce the demand for high-rated components and related factors: Figure, the present invention - a single-stage flyback power - η The circuit diagram of the example, the single-stage (4) system repairer 1 includes: - a power factor correction unit ω, a ^ 'wood-switching flyback converter 12 and - a DC bus capacitor 201112597 cb. Cut and drag, and the secondary side rectified two poles, such as ~ type conversion $ 12 and then - change (four) Tr, - sense Lik, an auxiliary switch wheel out ^ ^ C 〇 ' a main switch (^, a leakage K) again - The steps include...t'r clamp capacitor Ce. The power factor correction unit rate factor correction inductance Lp. He pump electric valley Cr' a clamp diode Dc and a power factor correction army - flow and adjust the input current core generated - low-spectrum wave-electricity with the same switch to switch back and its wheeled electric axis in the shared flexible switch Return control type 9 power factor correction unit 1 因数 rate factor correction = 彳 轻 轻 轻 功 功 功 的 的 的 的 的 的 直流 直流 直流 直流 直流 直流 直流 直流 直流 直流 直流 直流 直流 直流 直流 直流 直流 直流 直流 直流 直流 直流 直流 直流Switching the switch Qm of the flyback and the gate of the auxiliary switch Qa, according to the main switch to switch back to the converter: = and conduction, body_road_ and internal=electricity=transistor and less switching loss and improve Gongyang · Ancient, ώ, this I transfer to reduce the power factor correction unit 1 to the machine bus capacitor Cb, in series with the device 12 as a stored energy ☆ = parallel to the flexible switching flyback conversion room. In addition, the balance of the balance and the balance of the balance is also the ___ riding body, turn the main open, the system can be - extremely lightly connected to _ main open m said * and Np, and the main switch The source is coupled to the 201112597 DC busbar capacitor (the negative pole of ^) by controlling n 14 to adjust the source voltage between the main switch (6) and the timing and control of the main switch Qm. The one end of the leakage inductance Llk is coupled. The transformer is the primary side winding Np, and the other end is connected to the positive pole of the DC busbar capacitor Cb, which generates a leakage inductance electric current flowing through the primary side winding NP, and the secondary side of the transformer Tr is engaged to generate a secondary side. The current Isec, the transformer Tr in the flexible switching flyback converter 12, has a primary side winding and a secondary side winding Ns, and the secondary side of the transformer Tr is connected to the secondary side rectifying diode Ds and the output capacitor C., by the electric energy transmission φ to the secondary side of the transformer Tr to the output load and stored in the output capacitor C. And, the exciting inductance in the flexible switching flyback converter 12, is connected in series The side winding Np, the leakage current generated by the conduction current loop flows through the primary Winding &, that is, generating - excitation current lLm, the secondary side of the transformer produces secondary current Isec; its auxiliary switch (3) is a transistor with auxiliary switch body diode Dba, auxiliary switch 汲 _ DC The positive and leakage inductances Llk of the bus bar capacitor cb are controlled by the control 14 to adjust the waveform and timing of the auxiliary switch gate source V_ to control the on and off of the auxiliary switch 。. Finally, the clamp capacitor Cc, its end The source of the auxiliary switch is lightly connected, and the other end is coupled to the primary side of the exciting inductor Lm and the transformer Tr. When the auxiliary switch Qa is turned off, and the auxiliary switch body diode Dba is turned on, the leakage current 1 is also applied to the clamp capacitor Cc. Charging, and the excitation current U flows into the initial NP such that the two _ _ _ _ _ mosquito ^ ^ ^ 2 4 C. The money can provide energy to at least - the group of load devices 18 above the group. The rectifier 16 is placed at the input end of the power factor correction unit 1 (), the rectifier 16 is the wire-wound voltage Vb and the input current I, and the pulse is straight 201112597 = p:== full-bridge rectifier is taken. Connected to series power; 1 two-factor repair, sense current V D, pure pull & r and hanging diode Dc; clamp two pole straight,: sink: mine J electric pump capacitor Q and auxiliary switch Qa, and string contact to prevent DC bus capacitor (four) reverse The C system 1 is used as the Lai Ya limit circuit voltage; between the charge pump capacitor vertical capacitor Cc and the auxiliary switch Qa, which is used for the adjustment of the load transfer charge 4At capacitor electric lightening, see the third figure. One of the first rate correction converters 1 can be seen in 1 目士U 守守々^^ 1° Tiandi U,. _ /..., there are 6 (a ~ f) different working timing states. The actions of spreading the different working sequence states will be detailed below. The second figure is a working timing waveform diagram of a single-stage flyback type power embodiment of the present invention. Please refer to Figure 4A for the first time. When the circuit is in the state of a (tO-tl), the controller 14 controls the waveform of the main switch gate source Vgs (Qm) and the auxiliary source voltage Vgs (Qa}. And timing to make its main switch Qm turn on and subsidize open ilQa cutoff. Electric # pump capacitor Q, clamp capacitor c. and power factor repair f inductor Lp resonance; charge pump capacitor voltage Vr increases, charge pump capacitor cr charge; Capacitor voltage \lower 'clamp capacitance ce discharge. DC busbar capacitor Cb, 'is the input voltage source for the flexible switching flyback converter and discharges the magnetizing inductance and 'inductance Llk', and its excitation current and leakage inductance increase. Change the side to make the secondary ship diode Ds reverse. 5 Qing cooperate with reference to the fourth B1 diagram, the circuit action when the state is b (tl-t2), at U, the controller 14 controls the main switch gate The voltage Vgs (Qm) turns off the switch Qm. The energy of the charge pump capacitor Cr and the clamp capacitor Cc is transmitted 201112597 ^ DC scale capacitor Cb; the excitation current is charged by the parasitic capacitance coss of the main _ & The secondary side voltage of Tr is still insufficient to turn on the secondary side rectifying diode Ds. People i See fourth B 2, #Main open acid source voltage Vds_ reaches the sum of the straight capacitor voltage Vb and the clamp capacitor voltage ve (Vb+V) ^, the lion switch body diode Dba starts to conduct. The clamp capacitor Cc is caused by leakage inductance = main The voltage across the switch Qm, that is, the main switch, the source voltage Vds (Qm) will be made of citrus. The excitation current of 1Lm flows into the primary side winding Np. At this time, the transformer is twice.

The side voltage is sufficient for the secondary side rectifying diode Ds to be turned on and generate two ς sec stream I - please refer to the circuit diagram of the fourth c, when the state is c (7) 7), in the switching state, at t2 When the auxiliary switch Qa is turned on, the leakage inductance current 1 is reversed. In order to achieve zero voltage switching, the controller 14 controls the auxiliary open-f gate source vgs (Qa) to turn it on and off. The voltage of the charge pump capacitor Cr is zero, so the DC busbar capacitor is not stored during this period. The leakage inductance current flows through the primary side winding ^^ and charges the clamp capacitance cc. When the leakage current Iik continues to decrease, the energy is transmitted by the transformer and the coupled inductor to the secondary side of the transformer, and the secondary side of the transformer is turned on and the secondary current continuously increases. . Referring to the fourth D picture, the circuit action is when the state is d (t3-t4), and at time t3, the controller 14 controls the auxiliary switch source voltage Vgs (Qa) to turn off the auxiliary switch Qa. In this switching state, Leakage inductance Lik and the main capacitor L's capacitor (: (10), and parasitic capacitance. Continuous discharge, its main switch no source voltage VcMQnO continues to decrease, until t4, the main switch Qm cross-voltage that its main switch has no source Μ V·) has been reduced to zero. When the current Iik continues to increase, the secondary side current Isec of the transformer Tr secondary side rectifying diode is turned on and the Isec continues to decrease. In May, please refer to the fourth E diagram. When the state is e (t4-t5), the circuit action 'auxiliary switch 仏 and the main switch QmM are off. At t4, the main switch body one pole Dbm starts to conduct, making the main switch Qm can reach zero voltage conduction at t5. When the leakage current Ilk continues to increase, the secondary side rectifying diode Ds of the transformer Tr is turned on and the secondary current generated continuously decreases. Please refer to the fifth figure, which is the measured waveform of the main switch gate voltage and the main switch source voltage VdKQnO of the present invention, and it can be observed that there is zero voltage switching conduction (ZVS Tiim-on). In this switching state, the falling slope of the secondary current is expressed by the equation (1): η is the transformer ratio, that is, the primary side winding Np is larger than the secondary side winding wind. In order to make the main switch (^ zero power change, the auxiliary switch (3) is turned off and the main switch

The dead time Td of Qm conduction 1 can be determined by the formula:

Td=fVLmc^7 (2), the domain Td is determined by the parasitic capacitance c(10) and the square root of the leakage inductance product. ^ The time condition of equation (2) 'The energy of the leakage inductance Llk also needs to be enough for the parasitic, the valley C〇ss is completely discharged to reduce the main switch source voltage v·) to zero to achieve = voltage switching. In order to 謓Φ A i hard to zero is established: **Main _ Qm phase zero voltage city 'form (3) must also [ll^Lm'pk2 of Coss(Vb +nv〇)2 (3) where the voltage ' _ The electric riding value w can be given by the formula (4): the human side is >1" can be detailed: 'and

Lm’pk\+^T, (4) 201112597 I〇s,n 23⁄4 (5) ^l'8max)\ where P! is a single converter, δ riding cycle. : Refer to the fourth 己, the state is "take ((10)) circuit action, the two Si control switch 删 delete V - make it the main open L borrow ^ 'pushing capacitor Q and power factor correction inductance t; 4 In the switching mode, when the leakage inductance rises, the 'secondary current' continues to decrease. The second=, and the secondary side rectifying diode a is cut off. At this time, one (four) cycle is completed, the circuit Will return to state a. The present invention - a single-stage flyback power factor correction converter] in order to effectively f Qm voltage surge 'leakage inductance Llk and clamp capacitance (3) vibrations must be small enough. Clamp capacitance c The equation is as follows (6). Clamp Q — Λ 1" °min ) c (6) ^Cc,max ~nV0 (7)

Smin is the minimum duty cycle of the main switch Qm. Φ The average input current value after the gas is 丨 丨 丨 Mav=wq=fsCAVer=fsqVin| (^ml, av is not the formula (8): H electric capacitance charge amount and ^ is the electric hiding capacitance change. The formula (8) is close to the average input power of the body, and follows the shape of the input voltage νώ, so that it has a phase 'and thus can have high power factor characteristics.

Actually, when it is an embodiment of the present invention, the private transmission is shown in Figure 6A. When the input voltage is 90V waveform, the second: ΐVin waveform and the input current 1 waveform have approximate sine waves/, tend to be in phase; According to the six-B diagram*, when the input voltage 13 201112597 is 270V, the input voltage % waveform and the input current ΐώ waveform have approximate sine wave waveforms, so they tend to be in phase; in summary, please refer to the seventh figure, The seventh figure is a schematic diagram of the power factor obtained by the actual measurement according to the wide-area input voltage of 90V~270V. Its " power, number meets the requirements of ENERGY STAR's second edition of the specification for high efficiency and performance. The eighth diagram is the current of a single-stage flyback power factor correction converter according to an embodiment of the present invention. Harmonic and positive c 61〇〇〇_3_4

A comparison of the Class D current harmonic specifications with a bar graph. As can be seen from the figure, the current harmonics measured by the input voltages of 90V and 265V are smaller than and meet the specifications of the positive c current spectrum. The single-stage flyback power factor correction converter of the present invention is based on the balance between the output power and the charge pump capacitance Cr, which can be determined by the formula.

Cr = is, (9) Its +η is the conversion efficiency of the single-stage converter. The power factor correction inductance, and the resonant frequency of the charge pump electric valley Cr are designed as the switching frequency & the power factor correction inductance Lp can be determined as the formula (1〇). (1) The present invention is a single stage. The flyback power factor correction converter 〖, its DC busbar capacitor withstand voltage Vb眞 only needs to be the input electric dust edge value Vin,max. Therefore, the power switch of the single-stage power factor correction circuit and the DC bus capacitor q only require a lower voltage stress component. For example, under the input voltage of 2 qing, the DC bus bar Cb and the power switch are subjected to voltages of 3 8 〇乂 and 53 〇 v, respectively, so 450 V direct capacitor Cb and 6 (8) v power switch can be used. Just fine. And 'main switch resistance gVQ_, charge pump capacitor pressure stomach, secondary side rectifier diode withstand voltage vDsmax ' and DC busbar capacitor withstand voltage u 201112597 can be determined by the input voltage peak vinmax, the relationship equation is as follows (丨丨) to equation (14): VQm, max Vcr, max V〇s, max V2Vi; "^"Vin,max battle, n (Π) (12) ,+v〇(13) n, max + ΥΛΥΛ

Vb,max ^Vin.max (14) From the above-mentioned _ male type, it can be known that the voltage is reduced, the voltage is vCr, max, the secondary side rectifying diode, the voltage is Vd_, and the DC bus capacitor is Only vb,max requires only a lower voltage stress component. Fixed: DC bus capacitor Cb and output capacitor c. Equations (10) and (10) can be used to determine (15) (16)

2f!VbAVbir Pi , 2fiW where j ^^ and ~ are respectively DC bus capacitors and output capacitors; the amount of compression ripple is the mains frequency ripple. The single-stage flyback power factor correction switch II IJ switch Qm and the lion switch (10) conduction reduction and the main opening η provided by the present invention are switched between the one pole MDbm and the auxiliary switch body to reduce the loss, and R, From the stone...ba water S Γ Γ 使其 使其 与 与 ft % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % Ι Ι Ι Ι Ι Ι Ι Ι Ι ;^ 余面物b Lake components

Timef falls to the cause of high efficiency, high efficiency, and extended maintenance time (Hold_u industry and technology trends, that is, the present invention is in line with the current improvement of industrial competitiveness / ~, and, 匕, Lang can reduce carbon, and reduce costs; In the above, the detailed description of the specific embodiments of the present invention is not intended to limit the present invention, and all the scope of the present invention shall be subject to the scope of application, and anyone skilled in the art shall be present. Variations or modifications that can be easily conceived in the field of the invention are covered by the present invention. [Simplified description of the drawings] First figure: a two-stage series connection of a conventional discontinuous current flyback power factor correction converter Schematic diagram of the circuit of the architecture. Second diagram: a circuit diagram of a single-stage flyback power factor correction converter according to an embodiment of the present invention. Third diagram: a single-stage flyback power factor correction conversion according to an embodiment of the present invention The operation timing waveform diagram of the device. The fourth A diagram is a schematic diagram of the circuit operation when the state is a in the operation timing waveform of the third figure according to an embodiment of the present invention. The fourth B1 diagram is one of the inventions. The embodiment corresponds to the circuit operation diagram when the state is b in the working sequence waveform of the third figure. The fourth B2 diagram is a schematic diagram of the circuit operation when the state is b in the working timing waveform of the third figure according to an embodiment of the present invention. The fourth C diagram is a schematic diagram of the circuit operation when the state is c in the operation timing waveform of the third embodiment of the present invention. The fourth D diagram is an embodiment of the present invention corresponding to the third diagram working timing waveform. A schematic diagram of the circuit operation when the state is d. The fourth E diagram is a schematic diagram of the circuit operation when the state is e in the operation timing waveform of the third figure according to an embodiment of the present invention. The fourth F diagram is one of the inventions. The embodiment corresponds to the circuit operation diagram when the state is f in the working sequence waveform of the third figure. 16 201112597 FIG. 5: FIG. 1 is a zero voltage switching waveform diagram of a single-stage flyback power factor correction converter according to an embodiment of the present invention. FIG. 6A is a diagram showing an input voltage of 90 V and an input current waveform of a single-stage flyback power factor correction converter according to an embodiment of the present invention. FIG. 6B is an embodiment of the present invention. The input voltage of the power factor correction converter is 270V and the input current waveform diagram is the seventh diagram: #The power factor diagram of the single-stage flyback power factor correction converter of one embodiment of the present invention. _ The eighth figure: is the invention A comparison of the current harmonics of the single-stage flyback power factor correction converter and the IEC 61000-3-4 ClassD current wave specification. [Main component symbol description] 1 Single-stage flyback power factor correction Converter 1〇 Power factor correction unit Power factor correction inductor Lp _ Power factor correction inductor current Ip Charge pump capacitor C; Charge pump capacitor voltage % Charge pump capacitor charge amount 'charge pump capacitor voltage change Δν. Clamp diode Flexible switching flyback converter main switch Qm 17 201112597 Auxiliary open _Qa Auxiliary switch body diode Dba Main switch body diode Dbm Main switch gate voltage Vgs<Qn^ Auxiliary switch gate voltage VgS(Qa) Main switch Source voltage ^ ds (Qm) Parasitic capacitance cQSS Clamp capacitance cc Clamp capacitance voltage vc Transformer Tr Primary side winding Np Secondary side winding Ns Secondary side rectifying diode Ds output Yung C. Leakage inductance 13⁄4 Excitation inductance Lm Leakage current Ilk Secondary side current Isec Excitation current Ιτ, γπ Transformer turns ratio η 14 Controller dead time Td 16 Rectifier 18 201112597 Input current iin Average input current |Iin|,av Input voltage Vin Full Bridge Rectifier Br DC Bus Capacitor Cb DC Bus Capacitor Voltage vb Output Voltage V. Switching frequency fs 18 load device group 3 discontinuous current mode power factor correction converter 30 discontinuous current mode power factor correction control circuit 5 flyback DC/DC converter 50 current mode control circuit

19

Claims (1)

20111259' VII, the scope of application for patents: ~, a single-stage flyback power factor correction converter, including: ~ power due to the positive unit, is the hm frequency harmonic current; raw low ~ flexible switching back to jump converter And modifying, by the power factor, the internal switching component of the wooden switching flyback converter, and/or for outputting the power factor correction unit, and receiving a DC voltage that processes the output of the power correction unit; The μ rate is controlled by the H, _ 该 该 该 该 该 该 、 、 、 、 、 、 、 、 、 该 。 。 。 。 。 。 。 。 。 That is, the energy conversion between the internal components of the parallel converter is achieved for the purpose of switching between I and zero currents and returning current; and the package I and the zero-DC busbar capacitor are connected in series to the power factor trimming and paralleling Switching back to the fly-free mode, out of 4 and reduce the output voltage chopping and increase the maintenance time; Shibuya, thereby achieving a single-stage converter with high power. 2 The input shaft of the power factor correction unit in the single-stage power factor system described in the first item is connected to: 益 益 轮 轮 轮 轮 = = = = = = = = = = = = = = = = = = = = = = = = = = = The single stage described in item 2, the + the recorded ship type is gradually repaired. owed, 'having a primary side winding and a secondary side winding, and the secondary side is connected with a secondary side rectification The diode--capacitance, the peak-to-inductance is used to transmit energy to the buffer device. The energy is transmitted to the output capacitor; -*-卞艮育. The primary side winding is switched to the transformer, the main switch coupling The control of the straight 4 bus bar capacitor is controlled by the main switch. The _ leakage 戌 〃 〃 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻A primary side current is generated by the primary side winding, and the secondary side of the transformer, that is, a secondary side current; a magnetizing inductance, the worm is applied to the primary side winding, and the leakage current flows through the primary side winding j and g port; ^ & .. , "generate a magnetizing current, the secondary side of the transformer The secondary side current is generated by the coupling induction; the auxiliary + auxiliary switch is connected to the positive pole of the DC busbar capacitor and the leakage inductance, and the auxiliary switch is controlled to be turned on and off by the controller; and the one end is lightly The auxiliary switch is connected to the other end such as the magnetizing inductance and the primary side of the transformer. 4 The single-stage flyback power factor correction conversion benefit of the third aspect of the patent, wherein the power factor correction unit further comprises: The charge pump capacitor is lightly connected to the clamp capacitor and the auxiliary switch is used for storing energy and adjusting the average input current; the clamp diode is coupled between the electric capacitor and the auxiliary capacitor, and is connected in parallel The DC busbar capacitor is used to prevent the energy of the DC calendar capacitor from being backfilled to the charge pump capacitor to protect the lion circuit voltage; and a power factor correction inductor, which is 1 minus the charge pump capacitor and clamp The diode is coupled to the rectifier at the other end and generates a power correction inductor current. 21 201112597 5. Single-stage flyback power factor as described in claim 4 a modified converter, wherein the controller is coupled to the main switch and the auxiliary switch, and controls to adjust a control waveform and a timing of the main switch and the auxiliary switch. 6. Single-stage return as described in claim 5 The power factor correction converter, wherein the rectifier is a full-bridge rectifier. 7. The single-stage flyback power factor correction converter according to claim 5, wherein the output capacitor is coupled to the series one. At least one load device group. The single-stage flyback power factor correction converter according to claim 5, wherein the DC bus capacitance is an output filter capacitor of the power factor correction unit. The single-stage flyback power factor correction converter according to claim 5, wherein the DC busbar capacitor is an input voltage source of the flexible switching flyback converter. 10. The single-stage flyback power factor correction converter according to claim 4, wherein the main switch is a transistor having a parasitic capacitance and a φ main switch body diode, the transistor And the primary side winding of the transistor is switched to the anode of the DC bus capacitor, and the transistor is controlled to be turned on and off by the controller. 11. The single-stage flyback power factor correction converter according to claim 10, wherein the auxiliary switch is a transistor having an auxiliary switch body diode, and the transistor is coupled to the drain The anode of the DC busbar capacitor and the leakage inductance are controlled by the controller to turn on and off the transistor. 12. The single-stage flyback power factor 22 201112597 modified converter according to claim 11 , wherein the controller is coupled to the main switch and the auxiliary switch, and controls and adjusts the main switch gate voltage and the auxiliary The waveform and timing of the switching gate voltage. 13. The single-stage flyback power factor correction converter according to claim 12, wherein the controller controls the main switch and the auxiliary switch to turn off 5 and the auxiliary switch body diode is turned on The current charges the home capacitor, and the exciting current flows into the primary side winding, and the secondary side of the transformer also generates the secondary current and stores the output capacitor. 14. The single-stage flyback power factor correction converter according to claim 13 wherein the auxiliary switch is turned off and before the main switch is turned on. A dead time is caused by the parasitic capacitance and the leakage. The sense is multiplied by the square root. twenty three