Bridgeless PFC converter containing ZVS capacitor based on FSBB

Abstract

The invention discloses an FSBB-based bridgeless PFC converter containing a ZVS capacitor, and relates to the field of power electronic power converter topology, in particular to the field of bridgeless PFC converter topology containing the ZVS capacitor. The bridgeless Buck-Boost PFC converter is formed by changing the concept of a matrix rectifier on the basis of a four-switch Buck-Boost PFC with a diode rectifier bridge, and an optimization scheme for reducing the number of switch tubes is further obtained by analyzing the circuit structure and the working state. The converter consists of two groups of bidirectional switches Q1-Q2, Q3-Q4, a switching tube Q5, a switching tube Q6, an inductor Lc, a diode D1, a diode D2, a ZVS capacitor C1, a ZVS capacitor C2, an output capacitor Co and a load RL, wherein the bidirectional switches Q1-Q2 and Q3-Q4 are formed by two groups of switching tubes which are reversely connected in series; and each of the switching tubes Q1-Q6 comprises an anti-parallel diode and a junction capacitor. Compared with a traditional power factor correction converter, soft switching of the switching tubes in the whole domain range can be achieved, and the number of the switching tubes of the converter is reduced.

Description

Technical Field

[0001] The invention relates to the field of power electronic power converter topology, and in particular to a bridgeless PFC converter containing a ZVS capacitor based on FSBB. Background Art

[0002] With the increase in the power of various power electronic charging devices, the power grid's requirements for the harmonics of the converter are also increasing. In order to reduce the impact of harmonics, the power factor correction technology (Power Factor Correction, PFC) came into being. Its purpose is to make the input current as close to the sinusoidal change of the input voltage as possible and reduce the phase difference between the two when the input current is distorted and the waveform shape and phase of the input current are no longer consistent with the input voltage. PFC converters can be divided into active and passive modes according to whether they use active devices. Compared with the passive mode, the active mode has the advantages of high input power factor, small size, and low cost.

[0003] Usually, active PFC converters can adopt a variety of circuit topologies. Among them, the four-switch Buck-Boost PFC with a diode rectifier bridge has attracted widespread attention because of its advantages of being able to achieve buck-boost and full-range soft switching of the switch tube. However, its diode rectifier bridge has prominent losses, so it is necessary to find its bridgeless topology. Currently, the most commonly used bridgeless topologies include the diode clamped bridgeless Boost PFC converter, the totem pole bridgeless PFC converter, and the bidirectional switch bridgeless PFC converter. Summary of the invention

[0004] The purpose of the present invention is to optimize the four-switch Buck-Boost PFC with a diode rectifier bridge, and propose a new bridgeless topology. The number of switch tubes is reduced compared with the traditional four-switch bridgeless Buck-Boost PFC, which broadens the application scenarios of the converter.

[0005] The present invention adopts the following technical solutions to solve the above technical problems:

[0006] When the converter is working, the input AC voltage source v in One end is connected to the drain of the switch tube Q1 and the cathode of the diode D1, the source of the switch tube Q1 is connected to the source of the switch tube Q2, the drain of the switch tube Q2 is connected to the drain of the switch tube Q3 and the inductor L c The source of the switch tube Q3 is connected to the source of the switch tube Q4, and the input AC voltage source v in The other end is connected to the drain of the switch tube Q4 and the cathode of the diode D2. C1 and C2 are connected in parallel to the two ends of the diodes D1 and D2 respectively. The anodes of D1 and D2 are connected to the source of the switch tube Q6 and the load R L Connected to the G terminal, the inductor Lc The other end is connected to the source of the switch tube Q5 and the drain of the switch tube Q6. The drain of Q5 is connected to the load R L Connected to the H terminal, the output capacitor C o Same load R L in parallel.

[0007] The converter works in the inductor current quadrilateral modulation mode, and a filter can be added at the input end, and the filter is connected in parallel between the input end and the switch tube.

[0008] A bridgeless PFC converter based on FSBB and containing a ZVS capacitor, characterized in that: it includes an input AC voltage source v in , consisting of two sets of two reverse series connected switch tubes, bidirectional switches Q1~Q2, Q3~Q4, switch tube Q5, switch tube Q6, inductor L c , diode D1, diode D2, ZVS capacitor C1, ZVS capacitor C2, output capacitor C o and load R L , the switch tubes Q1~Q6 all include anti-parallel diodes and junction capacitors.

[0009] Furthermore, when the converter is working, the input AC voltage source v in One end is connected to the drain of the switch tube Q1 and the cathode of the diode D1, the source of the switch tube Q1 is connected to the source of the switch tube Q2, the drain of the switch tube Q2 is connected to the drain of the switch tube Q3 and the inductor L c The source of the switch tube Q3 is connected to the source of the switch tube Q4, and the input AC voltage source v in The other end is connected to the drain of the switch tube Q4 and the cathode of the diode D2. C1 and C2 are connected in parallel to the two ends of D1 and D2 respectively. The anodes of D1 and D2 are connected to the source of the switch tube Q6 and the load R L Connected to the G terminal, the inductor L c The other end is connected to the source of the switch tube Q5 and the drain of the switch tube Q6. The drain of Q5 is connected to the load R L Connected to the H terminal, the output capacitor C o Same load R L The converter works in the inductor current quadrilateral modulation mode, and a filter can be added at the input end, and the filter is connected in parallel between the input end and the switch tube.

[0010] Furthermore, all switches contain anti-parallel diodes and junction capacitors, defining the inductance L c The positive direction is positive on the left and negative on the right. The positive direction of the ZVS capacitor C1 is positive on the top and negative on the bottom. The positive direction of C2 is negative on the top and positive on the bottom. Taking the input voltage as an example, when the inductor current works in the PCRM mode, the converter has six working modes, from mode one to mode six.

[0011] Mode 1: Switches Q1, Q2, and Q5 are turned on, and the remaining switches are turned off. Inductor L c Bear v in -V o Positive pressure, inductance L c The current flows through diode D2 and rises in the forward direction;

[0012] Mode 2: Switches Q3, Q4, and Q5 are turned on, and the remaining switches are turned off. The inductor L c Bear-V o Voltage, inductance L c The current flows through diode D2 in the forward direction;

[0013] Mode 3: Switches Q3, Q4, and Q5 are turned on, and the remaining switches are turned off. The inductor L c Bear-V o Voltage, inductance L c The current flows through C2 and decreases in the reverse direction. c Resonance occurs with C2, and the inductor current i Lc Charge capacitor C2;

[0014] Mode 4: Switches Q1, Q2, and Q6 are turned on, and the remaining switches are turned off. The inductor L c Bear-v in Voltage, inductance L c The current flows through C2 and rises in the reverse direction. c Resonance occurs with C2, and the inductor current i Lc Continue to charge capacitor C2;

[0015] Mode 5: Switches Q1, Q2, and Q6 are turned on, and the remaining switches are turned off. The inductor L c Bear v in Voltage, inductance L c The current flows through C2 and rises positively, and the inductor L c Resonating with C2, the inductor current i Lc Discharge capacitor C2;

[0016] Mode 6: Switches Q1, Q2, and Q5 are turned on, and the other switches are turned off. The inductor L c Bear v in -V o Voltage, inductance L c The current flows through C2 and rises positively, and the inductor L c Resonance occurs with C2, and the inductor current i Lc Discharge capacitor C2 to 0.

[0017] Furthermore, the inductor current works in PDCM mode, and the inductor L is defined asc The positive direction is positive on the left and negative on the right. The positive direction of the ZVS capacitor C1 is positive on the top and negative on the bottom. The positive direction of C2 is negative on the top and positive on the bottom. The converter has six working modes, from mode seven to mode twelve.

[0018] Mode 7: Switches Q1, Q2, and Q5 are turned on, and the other switches are turned off. The inductor L c Bear v in -V o Positive pressure, inductance L c The current flows through diode D2 in the forward direction;

[0019] Mode 8: Switches Q3, Q4, and Q5 are turned on, and the remaining switches are turned off. The inductor L c Bear-V o Voltage, inductance L c The current flows through diode D2 in the forward direction;

[0020] Mode nine, switch tubes Q3, Q4, and Q5 are turned on, and the other switch tubes are turned off. The inductor L c Bear-V o Voltage, inductance L c The current flows through C2 and decreases in the reverse direction. c Resonance occurs with C2, and the inductor current i Lc Charge capacitor C2;

[0021] Mode 10: Switches Q3, Q4, and Q6 are turned on, and the remaining switches are turned off. Inductor L c Withstand zero voltage, inductance L c Resonance occurs with C2, and the inductor current i Lc Continue to charge capacitor C2;

[0022] Mode 11: Switches Q1, Q2, and Q6 are turned on, and the other switches are turned off. The inductor L c Bear-v in Voltage, inductance L c The current flows through C2 and rises in the reverse direction. c Resonance occurs with C2, and the inductor current i Lc Continue to charge capacitor C2;

[0023] Mode 12: switch tubes Q1, Q2, and Q6 are turned on, and the other switch tubes are turned off. The inductor L c Bear v in Voltage, inductance L c The current flows through C2 and rises positively, and the inductor L c Resonating with C2, the inductor current i Lc Discharge capacitor C2.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] (1) The present invention provides a bridgeless PFC converter based on FSBB and containing a ZVS capacitor, which has fewer switching tubes and optimized circuit structure compared with the previous one.

[0026] (2) The present invention provides a bridgeless PFC converter based on FSBB and containing a ZVS capacitor, which can realize soft switching in the entire domain, and the ZVS capacitor is beneficial to the soft switching of the switch tube.

[0027] (3) The present invention provides a bridgeless PFC converter based on FSBB and containing a ZVS capacitor, which realizes bidirectional energy flow. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the topological structure of a bridgeless PFC converter containing a ZVS capacitor based on FSBB according to the present invention;

[0029] Figure 2 The present invention works in v in ≥0 and the modal diagram when the switch tubes Q1, Q2, and Q5 are turned on;

[0030] Figure 3 The present invention works in v in ≥0 and the modal diagram when the switch tubes Q3, Q4, and Q5 are turned on;

[0031] Figure 4 The present invention works in v in ≥0 and the switch tubes Q3, Q4, Q5 are turned on and the modal diagram of the inductor current direction changes;

[0032] Figure 5 The present invention works in v in ≥0 and the modal diagram when the switch tubes Q1, Q2, and Q6 are turned on;

[0033] Figure 6 The present invention works in v in ≥0 and the switch tubes Q1, Q2, Q6 are turned on and the modal diagram of the inductor current direction changes;

[0034] Figure 7 The present invention works in v in ≥0 and the modal diagram when the switch tubes Q1, Q2, and Q5 are turned on;

[0035] Figure 8 The present invention works in v in ≥0 and the switch tubes Q3, Q4, and Q6 are turned on and the inductor current direction changes;

[0036] Fig. 9The present invention works in v in <0 and the modal diagram when the switch tubes Q3, Q4, and Q6 are turned on;

[0037] Fig.10 The present invention works in v in <0 and the switch tubes Q3, Q4, Q6 are turned on and the modal diagram of the inductor current direction changes;

[0038] Fig.11 The present invention works in v in <0 and the modal diagram when the switch tubes Q3, Q4, and Q5 are turned on;

[0039] Fig.12 The present invention works in v in <0 and the modal diagram when the switch tubes Q1, Q2, and Q5 are turned on;

[0040] Fig.13 The present invention works in v in <0 and the switch tubes Q1, Q2, Q5 are turned on and the inductor current direction changes modal diagram;

[0041] Fig.14 The present invention works in v in <0 and the modal diagram when the switch tubes Q1, Q2, and Q6 are turned on;

[0042] Fig.15 The present invention works in v in ≥0, the control signal of the switch tube and the inductor current work in the PCRM mode and the capacitor voltage v C2 Waveform diagram of

[0043] Fig.16 The present invention works in v in ≥0, the control signal of the switch tube and the inductor current work in PDCM (v in <V o ) mode and capacitor voltage v C2 Waveform diagram of

[0044] Fig.17 The present invention works in v in ≥0, the control signal of the switch tube and the inductor current work in PDCM (v in ≥V o ) mode and capacitor voltage v C2 Waveform diagram of

[0045] Fig.18 The present invention works in v in ≥0, the inductor current works in PCRM mode and the capacitor voltage v C2 Waveform diagrams of detailed operation;

[0046] Fig.19 The present invention works in v in ≥0, the inductor current works in PDCM mode and the capacitor voltage v C2 Waveform diagrams of detailed operation;

[0047] Fig. 20 The present invention works in The input voltage is 50Hz, 220VAC, the switching frequency is 500kHz, the output voltage is 300VDC, and the output power is P o 240W, inductor L c When the input voltage is 27μH, in 、Input current i in , inductor current i Lc , capacitor voltage v C1 、v C2 and the inductor current i Lc Waveform diagram of

[0048] Fig.21 The present invention works in the PCRM mode within the switching cycle. in 、Input current i in , inductor current i Lc , capacitor voltage v C1 、v C2 and the inductor current i Lc Waveform diagram of

[0049] Fig. 22 The present invention works in the PDCM mode within the switching cycle. in 、Input current i in , inductor current i Lc , capacitor voltage v C1 、v C2 and the inductor current i Lc Waveform diagram of DETAILED DESCRIPTION

[0050] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings of the specification. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in the art without creative work are within the scope of protection of the present invention.

[0051] A bridgeless PFC converter with ZVS capacitor based on FSBB, the scheme is as follows:

[0052] All switches are considered to contain anti-parallel diodes and junction capacitance. Taking the positive half cycle of the AC input voltage source as an example, the inductor current works in the PCRM (pseudo critical continuous current mode) mode. The main working waveform is as follows: Fig.18 As shown. Define the inductance L c The positive direction is positive on the left and negative on the right. The positive direction of the ZVS capacitor C1 is positive on the top and negative on the bottom, and the positive direction of C2 is negative on the top and positive on the bottom.

[0053] t a0 ~t a1 : Mode 1, such as Figure 2 As shown, switch tubes Q1, Q2, and Q5 are turned on, and the remaining switch tubes are turned off. c Bear v in -V o Positive pressure, inductance L c The current flows through the diode D2 and rises in the forward direction. The capacitor voltage v C2 With the inductor current i Lc The expression is:

[0054] v C2 (t)=0 (1)

[0055]

[0056] t a1 ~t a2 : Mode 2, such as Figure 3 As shown, the switch tubes Q3, Q4, and Q5 are turned on, and the other switch tubes are turned off. The inductor L c Bear-V o Voltage, inductance L c The current flows through the diode D2 and decreases in the forward direction. The capacitor voltage v C2 With the inductor current i Lc The expression is:

[0057] v C2 (t)=0 (3)

[0058]

[0059] t a2 ~t a3 : Mode three, such as Figure 4 As shown, the switch tubes Q3, Q4, and Q5 are turned on, and the other switch tubes are turned off. The inductor L c Bear-V o Voltage, inductance L c The current flows through C2 and decreases in the reverse direction. c Resonance occurs with C2, and the inductor current i LcCharge capacitor C2, inductor voltage, capacitor voltage and output voltage v Lc 、v C2 、V o And the inductor voltage v Lc and the inductor current i Lc The equation is as follows:

[0060]

[0061] According to formula (5), we can get C2 The equation is:

[0062]

[0063] The initial conditions are:

[0064]

[0065] Substituting equation (7) into equation (6) we can get the capacitor voltage v C2 With the inductor current i Lc The expression is:

[0066] v C2 (t)=-V o cosω1(tt a2 )+V o (8)

[0067]

[0068] Where the resonant angular frequency Resonant characteristic impedance

[0069] t a3 ~t a4 : Mode 4, such as Figure 5 As shown, the switch tubes Q1, Q2, and Q6 are turned on, and the other switch tubes are turned off. The inductor L c Bear-v in Voltage, inductance L c The current flows through C2 and rises in the reverse direction. c Resonance occurs with C2, and the inductor current i Lc Continue to charge capacitor C2, the inductor voltage, capacitor voltage and output voltage v Lc 、v C2 、V o And the inductor voltage v Lc and the inductor current i Lc The equation is as follows:

[0070]

[0071] According to formula (10), we can get C2 The equation is:

[0072]

[0073] Substituting the initial conditions, we can also solve for the capacitor voltage v C2 With the inductor current i Lc The expression is:

[0074] v C2 (t) = [v C2 (t a3 )+v in ]cosω1(tt a3 )-Z1i Lc (t a3 )sinω1(tt a3 )-v in (12)

[0075]

[0076] Where the resonant angular frequency Resonant characteristic impedance

[0077] t a4 ~t a5 : Mode five, such as Figure 6 As shown, the switch tubes Q1, Q2, and Q6 are turned on, and the other switch tubes are turned off. The inductor L c Bear v in Voltage, inductance L c The current flows through C2 and rises positively, and the inductor L c Resonating with C2, the inductor current i Lc Discharge capacitor C2, inductor voltage, capacitor voltage and output voltage v Lc 、v C2 、V o And the inductor voltage v Lc and the inductor current i Lc The equation is the same as equation (10), and the capacitor voltage v is also solved C2 With the inductor current i Lc The expression is:

[0078] v C2 (t) = [v C2 (t a4 )+v in ]cosω1(tt a4 )-Z1i Lc (t a4 )sinω1(tt a4 )-v in(14)

[0079]

[0080] Where the resonant angular frequency Resonant characteristic impedance

[0081] t a5 ~t a6 : Mode six, such as Figure 7 As shown, the switch tubes Q1, Q2, and Q5 are turned on, and the other switch tubes are turned off. The inductor L c Bear v in -V o Voltage, inductance L c The current flows through C2 and rises positively, and the inductor L c Resonance occurs with C2, and the inductor current i Lc Discharge capacitor C2 to 0, the inductor voltage, capacitor voltage and output voltage v Lc 、v C2 、V o And the inductor voltage v Lc and the inductor current i Lc The equation is as follows:

[0082]

[0083] According to formula (16), we can get C2 The equation is:

[0084]

[0085] Substituting the initial conditions, we can solve for the capacitor voltage v C2 With the inductor current i Lc The expression is:

[0086] v C2 (t) = [v C2 (t a5 )+v in -V o ]cosω1(tt a5 )-Z1i Lc (t a5 )sinω1(tt a5 )+V o -v in (18)

[0087]

[0088] Where the resonant angular frequency Resonant characteristic impedance

[0089] When the input voltage comes from the positive half cycle, the inductor current works in the PDCM (pseudo discontinuous current mode) mode. The main working waveform is as follows Fig.19 As shown. Define the inductance L c The positive direction is positive on the left and negative on the right. The positive direction of the ZVS capacitor C1 is positive on the top and negative on the bottom, and the positive direction of C2 is negative on the top and positive on the bottom.

[0090] t b0 ~t b1 : Mode 1, such as Figure 2 As shown, switch tubes Q1, Q2, and Q5 are turned on, and the remaining switch tubes are turned off. c Bear v in -V o Positive pressure, inductance L c The current flows through the diode D2 and decreases in the forward direction. The capacitor voltage v C2 With the inductor current i Lc The expression is:

[0091] v C2 (t)=0 (20)

[0092]

[0093] t b1 ~t b2 : Mode 2, such as Figure 3 As shown, the switch tubes Q3, Q4, and Q5 are turned on, and the other switch tubes are turned off. The inductor L c Bear-V o Voltage, inductance L c The current flows through the diode D2 and decreases in the forward direction. The capacitor voltage v C2 With the inductor current i Lc The expression is:

[0094] v C2 (t)=0 (22)

[0095]

[0096] t b2 ~t b3 : Mode three, such as Figure 4 As shown, the switch tubes Q3, Q4, and Q5 are turned on, and the other switch tubes are turned off. The inductor L c Bear-V o Voltage, inductance L c The current flows through C2 and decreases in the reverse direction. c Resonance occurs with C2, and the inductor current i Lc Charge capacitor C2, inductor voltage, capacitor voltage and output voltage vLc 、v C2 、V o And the inductor voltage v Lc and the inductor current i Lc The equation is as follows:

[0097]

[0098] Substituting the initial conditions into equation (5) yields the capacitor voltage v C2 With the inductor current i Lc The expression is:

[0099] v C2 (t)=-V o cosω1(tt b2 )+V o (25)

[0100]

[0101] Where the resonant angular frequency Resonant characteristic impedance

[0102] t b3 ~t b4 : Mode 4, such as Figure 8 As shown, the switch tubes Q3, Q4, and Q6 are turned on, and the other switch tubes are turned off. The inductor L c Withstand zero voltage, inductance L c Resonance occurs with C2, and the inductor current i Lc Continue to charge capacitor C2, the inductor voltage, capacitor voltage and output voltage v Lc 、v C2 、V o And the inductor voltage v Lc and the inductor current i Lc The equation is as follows:

[0103]

[0104] Substituting the initial conditions, we can solve for the capacitor voltage v C2 With the inductor current i Lc The expression is:

[0105] v C2 (t) = v C2 (t b3 )cosω1(tt b3 )-Z1i Lc (t a3 )sinω1(tt b3 ) (28)

[0106]

[0107] Where the resonant angular frequency Resonant characteristic impedance

[0108] t b4 ~t b5 : Mode five, such as Figure 5 As shown, the switch tubes Q1, Q2, and Q6 are turned on, and the other switch tubes are turned off. The inductor L c Bear-v in Voltage, inductance L c The current flows through C2 and rises in the reverse direction. c Resonance occurs with C2, and the inductor current i Lc Continue to charge capacitor C2, the equation is the same as equation (11), the capacitor voltage v C2 With the inductor current i Lc The expression is:

[0109] v C2 (t) = [v C2 (t b4 )+v in ]cosω1(tt b4 )-Z1i Lc (t b4 )sinω1(tt b4 )-v in (30)

[0110]

[0111] Where the resonant angular frequency Resonant characteristic impedance

[0112] t b5 ~t b6 : Mode six, such as Figure 6 As shown, the switch tubes Q1, Q2, and Q6 are turned on, and the other switch tubes are turned off. The inductor L c Bear v in Voltage, inductance L c The current flows through C2 and rises positively, and the inductor L c Resonating with C2, the inductor current i Lc Discharge capacitor C2, inductor voltage, capacitor voltage and output voltage v Lc 、v C2 、V o And the inductor voltage v Lc and the inductor current i Lc The equation is the same as equation (11), and the capacitor voltage v is also solved C2 With the inductor current iLc The expression is:

[0113] v C2 (t) = [v C2 (t b5 )+v in ]cosω1(tt b5 )-Z1i Lc (t b5 )sinω1(tt b5 )-v in (32)

[0114]

[0115] Where the resonant angular frequency Resonant characteristic impedance

[0116] Define T s is a switching cycle. T1 is the voltage on the inductor during a switching cycle |v in | time; T2 is the voltage on the inductor during a switching cycle |v in |-V o T3 is the time when the voltage on the inductor is -V in one switching cycle. o T4 is the time when the voltage on the inductor is 0 in one switching cycle. zvs is the soft switching current of the switch tube, L c is the inductance value, P o is the output power. The PCRM working mode is as follows Fig.15 , v in <V o When the PDCM working mode is Fig.16 , v in ≥V o When the PDCM working mode is Fig.17 .

[0117]

[0118] Under these three inductor current conditions, the input current of a FSBB-based bridgeless PFC converter with ZVS capacitor is analyzed respectively, and the expressions of equations T1, T2 and T3 in each mode can be obtained.

[0119] When the inductor current is in PCRM, the expressions of T1, T2 and T3 are (34).

[0120] v in ≥V o When the inductor current is in PDCM, the expressions of T1, T2 and T3 are (35).

[0121]

[0122] v in <V o When the inductor current is in PDCM, the expressions of T1, T2 and T3 are (36).

[0123]

[0124] Take v in The input voltage is 50Hz, 220VAC, the switching frequency is 500kHz, the output voltage is 300VDC, and the output power is P o 240W, inductor L c is 27μH.

[0125] The power factor correction of a bridgeless PFC converter based on FSBB and containing ZVS capacitors under the above circuit parameters is shown as follows: Fig. 20 As shown in the simulation results, it can be seen that the converter input current i under quadrilateral current modulation in It presents a sine wave and can track the input voltage waveform in real time, with good power factor correction effect.

[0126] The above are only preferred embodiments of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that all other embodiments obtained by ordinary technicians in this field without creative work belong to the protection scope of the present invention.

Claims

1. A bridgeless PFC converter with ZVS capacitor based on FSBB, characterized in that: Including input AC voltage source v in , consisting of two sets of two reverse series connected switch tubes, bidirectional switches Q1~Q2, Q3~Q4, switch tube Q5, switch tube Q6, inductor L c , diode D1, diode D2, ZVS capacitor C1, ZVS capacitor C2, output capacitor C o and load R L , the switch tubes Q1~Q6 all include anti-parallel diodes and junction capacitors.

2. The bridgeless PFC converter with ZVS capacitor based on FSBB according to claim 1, characterized in that: When the converter is working, the input AC voltage source v in One end is connected to the drain of the switch tube Q1 and the cathode of the diode D1, the source of the switch tube Q1 is connected to the source of the switch tube Q2, the drain of the switch tube Q2 is connected to the drain of the switch tube Q3 and the inductor L c The source of the switch tube Q3 is connected to the source of the switch tube Q4, and the input AC voltage source v in The other end is connected to the drain of the switch tube Q4 and the cathode of the diode D2. C1 and C2 are connected in parallel to the two ends of D1 and D2 respectively. The anodes of D1 and D2 are connected to the source of the switch tube Q6 and the load R L Connected to the G terminal, the inductor L c The other end is connected to the source of the switch tube Q5 and the drain of the switch tube Q6. The drain of Q5 is connected to the load R L Connected to the H terminal, the output capacitor C o Same load R L in parallel.

3. The bridgeless PFC converter with ZVS capacitor based on FSBB according to claim 1, characterized in that: All switches contain anti-parallel diodes and junction capacitances, defining the inductance L c The positive direction is positive on the left and negative on the right. The positive direction of the ZVS capacitor C1 is positive on the top and negative on the bottom. The positive direction of C2 is negative on the top and positive on the bottom. When the input voltage comes from the positive half cycle, the inductor current works in the PCRM mode. In this state, the converter has six working modes, from mode one to mode six. Mode 1: Switches Q1, Q2, and Q5 are turned on, and the remaining switches are turned off. Inductor L c Bear v in -V o Positive pressure, inductance L c The current flows through diode D2 in the forward direction; Mode 2: Switches Q3, Q4, and Q5 are turned on, and the remaining switches are turned off. The inductor L c Bear-V o Voltage, inductance L c The current flows through diode D2 in the forward direction; Mode 3: Switches Q3, Q4, and Q5 are turned on, and the remaining switches are turned off. The inductor L c Bear-V o Voltage, inductance L c The current flows through C2 and decreases in the reverse direction. c Resonance occurs with C2, and the inductor current i Lc Charge capacitor C2; Mode 4: Switches Q1, Q2, and Q6 are turned on, and the remaining switches are turned off. The inductor L c Bear-v in Voltage, inductance L c The current flows through C2 and rises in the reverse direction. c Resonance occurs with C2, and the inductor current i Lc Continue to charge capacitor C2; Mode 5: Switches Q1, Q2, and Q6 are turned on, and the remaining switches are turned off. The inductor L c Bear v in Voltage, inductance L c The current flows through C2 and rises positively, and the inductor L c Resonating with C2, the inductor current i Lc Discharge capacitor C2; Mode 6: Switches Q1, Q2, and Q5 are turned on, and the other switches are turned off. The inductor L c Bear v in -V o Voltage, inductance L c The current flows through C2 and rises positively, and the inductor L c Resonance occurs with C2, and the inductor current i Lc Discharge capacitor C2 to 0.

4. The bridgeless PFC converter with ZVS capacitor based on FSBB according to claim 1, characterized in that: When the input voltage comes from the positive half cycle, the inductor current works in PDCM mode, and the inductor L is defined as c The positive direction is positive on the left and negative on the right. The positive direction of the ZVS capacitor C1 is positive on the top and negative on the bottom. The positive direction of C2 is negative on the top and positive on the bottom. The converter has six working modes, from mode seven to mode twelve. Mode 7: Switches Q1, Q2, and Q5 are turned on, and the other switches are turned off. The inductor L c Bear v in -V o Positive pressure, inductance L c The current flows through diode D2 in the forward direction; Mode 8: Switches Q3, Q4, and Q5 are turned on, and the remaining switches are turned off. Inductor L c Bear-V o Voltage, inductance L c The current flows through diode D2 in the forward direction; Mode nine, switch tubes Q3, Q4, and Q5 are turned on, and the other switch tubes are turned off. The inductor L c Bear-V o Voltage, inductance L c The current flows through C2 and decreases in the reverse direction. c Resonance occurs with C2, and the inductor current i Lc Charge capacitor C2; Mode 10: Switches Q3, Q4, and Q6 are turned on, and the remaining switches are turned off. Inductor L c Withstand zero voltage, inductance L c Resonance occurs with C2, and the inductor current i Lc Continue to charge capacitor C2; Mode 11: Switches Q1, Q2, and Q6 are turned on, and the other switches are turned off. The inductor L c Bear-v in Voltage, inductance L c The current flows through C2 and rises in the reverse direction. c Resonance occurs with C2, and the inductor current i Lc Continue to charge capacitor C2; Mode 12: switch tubes Q1, Q2, and Q6 are turned on, and the other switch tubes are turned off. The inductor L c Bear v in Voltage, inductance L c The current flows through C2 and rises positively, and the inductor L c Resonating with C2, the inductor current i Lc Discharge capacitor C2.

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