CN214315050U

CN214315050U - Wide-voltage hybrid PFC converter and switching power supply

Info

Publication number: CN214315050U
Application number: CN202120083365.0U
Authority: CN
Inventors: 胡炎申
Original assignee: Moso Power Supply Technology Co ltd
Current assignee: Moso Power Supply Technology Co ltd
Priority date: 2021-01-13
Filing date: 2021-01-13
Publication date: 2021-09-28
Anticipated expiration: 2031-01-13

Abstract

The utility model discloses a wide voltage hybrid PFC converter and switching power supply, the converter includes AC input unit, the rectifier unit, first input filter capacitor, first output filter capacitor, second input filter capacitor, second output filter capacitor, the selector switch, PFC transform unit and PFC the control unit, rectifier unit AC input end is connected to AC input unit's AC output electricity, the first input of the first input filter capacitor of output termination and PFC transform unit of rectifier unit, the second input of output second input filter capacitor and PFC transform unit of rectifier unit. According to the scheme, power conversion is realized through the PFC conversion unit, the selection switch is switched on and off according to the size of the alternating current voltage so as to adapt to a wider alternating current input voltage range, the size of the input current is basically kept unchanged, and when the selection switch is switched off, the PFC conversion unit works in a bridgeless rectification mode, so that the overall conversion efficiency can be improved; the requirement of the power device is low, and the production cost is reduced.

Description

Wide-voltage hybrid PFC converter and switching power supply

Technical Field

The utility model relates to a power topological structure field, the more specifically wide voltage hybrid PFC converter and switching power supply that says so.

Background

Power electronic devices and switching power supplies are widely used in various consumer electronics and industrial equipment, such as chargers, power adapters, LED drivers, industrial control power supplies, charging post modules, 5G communication power supplies, etc., and need to have a Power Factor Correction (PFC) function when power exceeds a prescribed power. The power converter is a core component of a power electronic device and a switching power supply, and generally and widely adopts a two-stage AC/DC cascade structure: the front-stage PFC converter is used for adjusting an input power factor and realizing input and output energy balance; and a post-stage DC/DC converter for adjusting the output voltage and reducing the output ripple voltage or current. In a two-stage AC/DC converter, a Boost converter (Boost) is generally used as a pre-stage PFC converter; the later-stage DC/DC converter can use an isolation type and also can use a non-isolation topological structure. An existing pre-stage PFC converter is shown in fig. 1, where Lf and Cf are input EMI filter inductors and filter capacitors, D1, D2, D3 and D4 are input rectifier bridge diodes, Cin is an input filter capacitor, Cb is a dc bus capacitor to balance input and output energy and to be used as a filter, Co is an output filter capacitor, RL is a dc output load, and the Boost converter includes a first power switch Q1, a first body diode DQ1, a first filter inductor L1, and a first rectifier diode D5. The basic working principle of the Boost PFC converter is as follows: when Q1 is switched on, L1 stores energy, and Co provides energy for RL; the L1 discharge when Q1 is off provides energy to Co and RL.

In order to be able to operate reliably for long periods of time, switching power supplies must accommodate a wide range of alternating current network voltage (AC) variations. However, industrial electricity has large voltage fluctuation, and the global power grid system and the voltage grade are different, so that the alternating voltage range is 85-305Vac and works in such an extremely wide voltage range, and the Boost converter has serious problems: on one hand, the power device needs larger voltage, current and power level, so that the cost of the device is increased sharply; on the other hand, because the voltage of the direct-current bus is basically fixed, the current stress of the power device is more than two times when alternating-current low-voltage input is carried out, more power consumption is inevitably generated, and therefore the overall conversion efficiency is reduced. Other types of converters, such as Buck converters (Buck), Buck-Boost converters (Buck-Boost), Flyback converters (Flyback), etc., have been tried, but have the disadvantages of low Power Factor (PF), large current harmonics (THD), low conversion efficiency, limited power capacity, etc. when used in PFC.

Therefore, a new PFC converter is needed in the power electronics and switching power supply industries.

The information disclosed in this background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information constitutes prior art already known to a person skilled in the art.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to overcome prior art's not enough, provide a wide voltage hybrid PFC converter and switching power supply.

In order to achieve the above purpose, the utility model adopts the following technical scheme:

in a first aspect, the present invention provides a wide voltage hybrid PFC converter, comprising an AC input unit, a rectifying unit, a first input filter capacitor, a first output filter capacitor, a second input filter capacitor, a second output filter capacitor, a selection switch, a PFC conversion unit, and a PFC control unit;

the alternating current output end of the AC input unit is electrically connected with the alternating current input end of the rectifying unit, the first output end of the rectifying unit is connected with the first end of the first input filter capacitor and the first input end of the PFC conversion unit, the second output end of the rectifying unit is connected with the first end of the second input filter capacitor and the second input end of the PFC conversion unit, the first end of the selector switch is connected with the second end of the first input filter capacitor, the second end of the second input filter capacitor and the first connection end of the PFC conversion unit, and the second end of the selector switch is connected with the alternating current input end of the rectifying unit; the first output end of the PFC conversion unit is connected with the first output filter capacitor and the first end of the load, the second output end of the PFC conversion unit is connected with the first end of the second output filter capacitor and the second end of the load, the second ends of the first output filter capacitor and the second output filter capacitor are connected with the second connecting end of the PFC conversion unit, and the first connecting end and the second connecting end of the PFC conversion unit are communicated; the control end of the PFC control unit is connected with the controlled end of the selection switch, the first sampling end of the PFC control unit is connected with the first input end or the second output end of the PFC conversion unit and is used for sampling the input voltage of the PFC conversion unit, the second sampling end of the PFC control unit is connected with the first output end or the second output end of the PFC conversion unit and is used for sampling the output voltage of the PFC conversion unit, and the modulation end of the PFC control unit is connected with the PFC conversion unit.

In a second aspect, the present invention further provides a switching power supply including the wide voltage hybrid PFC converter as described above.

Compared with the prior art, the utility model beneficial effect be: the utility model provides a pair of wide voltage hybrid PFC converter and switching power supply, wide voltage hybrid PFC converter comprises PFC transform unit and select switch and PFC the control unit, PFC transform unit realizes power conversion, select switch closes and breaks off according to alternating voltage size in order to adapt to the wide AC input voltage scope, the input current size remains unchanged basically, wherein, when select switch closed, PFC transform unit work in bridgeless rectification mode to can improve whole conversion efficiency; in addition, the PFC control unit is matched with the selection switch, so that high power factor and low current harmonic can be realized; in addition, the power device adopted by the scheme does not need to increase the voltage, the current and the power level, so that the cost of components can be reduced.

The foregoing is a summary of the present invention, and other objects, features and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments, which is provided for the purpose of illustration and understanding of the present invention.

Drawings

Fig. 1 is a circuit diagram of a prior art pre-stage PFC converter;

fig. 2 is a schematic diagram of a first embodiment of a wide voltage hybrid PFC converter according to the present invention;

fig. 3 is a circuit diagram of a second embodiment of a wide voltage hybrid PFC converter according to the present invention;

fig. 4 is a circuit diagram of a PFC unit according to a third embodiment of the present invention;

fig. 5 is a circuit diagram of a fourth embodiment of a wide voltage hybrid PFC converter according to the present invention;

fig. 6 is a circuit diagram of a PFC unit according to a fifth embodiment of the wide voltage hybrid PFC converter of the present invention;

fig. 7 is a circuit diagram of a PFC unit according to a sixth embodiment of the wide voltage hybrid PFC converter of the present invention;

fig. 8 is a circuit diagram of a PFC unit according to a seventh embodiment of the wide-voltage hybrid PFC converter of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more clearly understood, the present invention will be described in further detail with reference to the accompanying drawings and the following detailed description.

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those skilled in the art without creative efforts belong to the protection scope of the present invention.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and to simplify the description, but do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be construed as limiting the present invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically limited otherwise.

In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "secured" are to be construed broadly and can, for example, be connected or detachably connected or integrated; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meaning of the above terms in the present invention can be understood according to specific situations by those skilled in the art.

In the present disclosure, unless expressly stated or limited otherwise, the first feature "on" or "under" the second feature may comprise direct contact between the first and second features, or may comprise contact between the first and second features not directly. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above should not be understood to necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples described in this specification can be combined and combined by one skilled in the art.

The first embodiment:

referring to fig. 1, the present invention provides a wide voltage hybrid PFC converter, which includes an AC input unit 10, a rectifying unit 20, a first input filter capacitor Ci1, a first output filter capacitor Co1, a second input filter capacitor Ci2, a second output filter capacitor Co2, a selector switch K, PFC converting unit 30 and a PFC control unit 40.

As shown in fig. 1, in the present embodiment, the AC input unit 10 includes an EMI filter inductor Lf and an EMI filter capacitor Cf, the EMI filter inductor Lf is disposed on a zero line or a live line, one end of the EMI filter capacitor Cf is connected to the zero line and the other end is connected to the live line, and the EMI filter inductor Lf cooperates with the EMI filter capacitor Cf to filter the AC power of the AC input unit 1010.

As shown in fig. 1, in the present embodiment, the rectifying unit 20 includes 4 rectifying bridge diodes (D1, D2, D3, and D4), the 4 rectifying bridge diodes (D1, D2, D3, and D4) are connected to form a bridge rectifying circuit, two AC output terminals of the AC input unit 10 are respectively connected to two AC input terminals of the bridge rectifying circuit, and positive and negative output terminals (first and second output terminals) of the rectifying unit 20 are connected to the PFC converting unit 30, and are configured to output the rectified dc power to the PFC converting unit 30.

A first output end of the rectifying unit 20 is connected with a first end of a first input filter capacitor and a first input end (port 1) of the PFC conversion unit 30, a second output end of the rectifying unit 20 is connected with a first end of a second input filter capacitor and a second input end (port 3) of the PFC conversion unit 30, a first end of the selection switch is connected with a second end of the first input filter capacitor, a second end of the second input filter capacitor and a first connection end (port 2) of the PFC conversion unit 30, and a second end of the selection switch is connected with an alternating current input end of the rectifying unit 20; a first output end (4 port) of the PFC conversion unit 30 is connected with a first output filter capacitor and a first end of a load, a second output end (6 port) of the PFC conversion unit 30 is connected with a first end of a second output filter capacitor and a second end of the load, second ends of the first output filter capacitor and the second output filter capacitor are connected with a second connecting end (5 port) of the PFC conversion unit 30, and the first connecting end and the second connecting end of the PFC conversion unit 30 are communicated; the control end of the PFC control unit is connected to the controlled end of the selection switch, the first sampling end of the PFC control unit is connected to the first input end or the second output end of the PFC conversion unit 30 and is used for sampling the input voltage of the PFC conversion unit 30, the second sampling end of the PFC control unit 40 is connected to the first output end or the second output end of the PFC conversion unit 30 and is used for sampling the output voltage of the PFC conversion unit 30, and the modulation end of the PFC control unit 40 is connected to the PFC conversion unit 30.

In the present embodiment, various types of switching devices can be used for the selection switch K. Such as electromagnetic switches like relays and reed switches, or electronic switches like MOSFETs, IGBTs, thyristors, or a combination thereof.

The PFC control unit 40 controls the selection switch K to enter a closed state and an off state, and the PFC conversion unit 30 has two working modes of bridgeless rectification and bridgeless rectification, which are specifically as follows:

1. in the bridgeless rectification working mode, when the PFC control unit 40 detects that the ac voltage is low, the PFC control unit 40 closes the selection switch K, and the wide-voltage hybrid PFC converter enters the bridgeless rectification working mode. As shown in fig. 2, during the positive half cycle of the sine wave, the AC power of the AC input unit 10 passes through D1, and is filtered by Ci1 to supply power to the 1 st and 2 nd ports of the PFC converter unit 30, where the 1 st port is a positive electrode and the 2 nd port is a negative electrode. In the process of a negative half cycle of the sine wave, alternating current of the AC input unit 10 passes through D3 and is filtered by Ci2 to supply power to the 2 nd and 3 rd ports, wherein the 2 nd port is a positive electrode, and the 3 rd port is a negative electrode. That is, when K is closed, the 1 st port and the 2 nd port and the 3 nd port work in a time-sharing mode, and Ci1 and Ci2 are charged by AC input voltage in each half power frequency period. Because D2, D4 of rectifying unit 20 do not work in the whole process, thus work in the bridgeless rectification mode, the conduction loss of the diode of the input rectifier bridge can be reduced by half, and the whole conversion efficiency is improved.

2. When the bridge rectification working mode is adopted, and the PFC control unit 40 detects that the alternating-current voltage is higher, the PFC control unit 40 turns off the selection switch K, and the wide-voltage hybrid PFC converter enters the bridge rectification working mode. As shown in fig. 2, during the positive half cycle of the sine wave, the alternating current of the AC input unit 10 passes through D1 and D4, and is filtered by Ci1 and Ci2 in series, and then supplies power to the 1 st and 3 rd ports of the PFC converter unit 30, where the 1 st port is a positive electrode and the 3 rd port is a negative electrode; in the process of a sine wave negative half cycle, an AC input passes through D2 and D3 and is also filtered in series by Ci1 and Ci2 to supply power to the 1 st port and the 3 rd port, wherein the 1 st port is a positive electrode, and the 3 rd port is a negative electrode. That is, only the 1 st port and the 3 rd port work when the K is disconnected, and the AC input voltage simultaneously charges Ci1 and Ci2 in series connection in each power frequency period. In the process, D1, D2, D3 and D4 all work so as to work in a PFC bridge rectification mode, and the power loss and the conversion efficiency are similar to those of a traditional Boost PFC converter. In order to adapt to a wider alternating current input voltage range, the selection switch K has two states of closing and opening, and the PFC converter works in a bridgeless rectification mode and a bridge rectification mode respectively, so that the hybrid PFC converter is formed. Because the circuit is provided with the selection switch K, the voltages of the 1 st port and the 3 rd port are basically unchanged when different alternating current input voltages are input, and the input current magnitude of the bridgeless rectification mode when alternating current low voltage is input and the input current magnitude of the bridgeless rectification mode when alternating current high voltage is input are basically maintained unchanged, the whole conversion efficiency can be further improved.

In the embodiment, the PFC control unit 40 and the selection switch detection and control circuit are in communication connection to coordinate respective control and operation, so that real-time instructions and operation parameters are mutually transmitted between the PFC control unit 40 and the selection switch detection and control circuit, and a control mode and an operation state can be set to optimize the operation of the PFC conversion unit 30, thereby further improving the performance and reliability of the wide-voltage hybrid PFC converter.

Further, the PFC controller and the selection switch detection and control circuit can be integrated into one, two or more analog chips, or one, two or more digital chips such as MCU, DSP and the like which need embedded software programming can be used.

The wide-voltage hybrid PFC converter is composed of a PFC conversion unit 30, a selection switch and a PFC control unit 40, wherein the PFC conversion unit 30 realizes power conversion, the selection switch is switched on and off according to the size of alternating-current voltage so as to adapt to a wider alternating-current input voltage range, and the size of input current is basically kept unchanged, wherein when the selection switch is switched off, the PFC conversion unit 30 works in a bridgeless rectification mode, so that the overall conversion efficiency can be improved; in addition, the PFC control unit 40 is matched with a selection switch, so that high power factor and low current harmonic can be realized.

Second embodiment:

referring to fig. 1 and 3, the present invention provides a wide voltage hybrid PFC converter, including an AC input unit 10, a rectifying unit 20, a first input filter capacitor Ci1, a first output filter capacitor Co1, a second input filter capacitor Ci2, a second output filter capacitor Co2, a selector switch K, PFC converting unit 30 and a PFC control unit 40.

In the present embodiment, the AC input unit 10, the rectifying unit 20, the first input filter capacitor Ci1, the first output filter capacitor Co1, the second input filter capacitor Ci2, the second output filter capacitor Co2, and the selection switch K are the same as those of the first embodiment, and a description thereof will not be repeated.

Referring to fig. 3, in the present embodiment, the PFC converter unit 30 includes a first power switch Q1, a first body diode DQ1, a first rectifier diode D5, a first smoothing inductor L1, a second power switch Q2, a second body diode DQ2, a second rectifier diode D6, and a second smoothing inductor L2.

Specifically, the D pole of the first power switch Q1 and the negative pole of the first body diode DQ1 are connected to the first input end of the PFC converter unit 30, the G pole of the first power switch Q1 is connected to the modulation end of the PFC control unit 40, the S pole of the first power switch Q1 and the positive pole of the first body diode DQ1 are connected to the negative pole of the first rectifier diode D5 and the first end of the first filter inductor L1, and the second end of the first filter inductor L1 is connected to the first output end of the PFC converter unit 30; the S pole of the second power switch tube Q2 and the positive pole of the second body diode DQ2 are connected with the second input end of the PFC conversion unit 30, the G pole of the second power switch tube Q2 is connected with the modulation end of the PFC control unit 40, the D pole of the second power switch tube Q2 and the negative pole of the second body diode DQ2 are connected with the positive pole of the second rectifier diode D6 and the first end of the second filter inductor L2, and the second end of the second filter inductor L2 is connected with the second output end of the PFC conversion unit 30; the anode of the first rectifying diode D5 and the cathode of the second rectifying diode D6 are connected to the first connection terminal and the second connection terminal of the PFC converter unit 30.

Specifically, the topology structure of the PFC converter unit 30 is a positive-negative symmetric Buck converter (Buck), the positive Buck converter includes a first power switch Q1, a first body diode DQ1, a first filter inductor L1, and a first rectifier diode D5, and an output end of the positive Buck converter serves as a first positive output voltage Vo 1; the negative buck converter comprises a second power switch tube Q2, a second body diode DQ2, a second filter inductor L2 and a second rectifier diode D6, and the output end of the second power switch tube Q2 is used as a second positive output voltage Vo 2; vo1 and Vo2 are connected in series across the positive and negative poles of the total output voltage Vo to power the output load RL. In actual operation, an alternating current power grid (AC) is subjected to EMI filtering of Lf and Cf, rectified by D1, D2, D3 and D4, filtered by Ci1 and Ci2, and then provided to the 1 st and 3 rd ports of the PFC converter unit 30 with positive and negative symmetry, that is, the input positive and negative electrodes of the PFC converter unit. The midpoint of each of Ci1 and Ci2 is connected to the 2 nd port of the PFC converter unit 30, i.e., the midpoint of L1 and L2, and is connected to the midpoint of D2 and D4 or any end of the AC live line (L) or neutral line (N) through a selector switch K. Through internal power conversion, after being filtered by the output capacitors Co1 and Co2, the output of the output capacitor is connected to the 4 th port and the 6 th port to generate an output voltage Vo and supply power to the output load RL, namely the output positive and negative electrodes of the output capacitor, the middle points of Co1 and Co2 are connected to the 5 th port of the PFC conversion unit 30 to form output voltage division, and the output voltage division is connected with the 2 nd port.

The PFC control unit 40 controls the selection switch K to enter a closed state and an off state, and the wide-voltage hybrid PFC converter of the present scheme correspondingly enters two working modes, namely, a bridgeless rectification mode and a bridgeless rectification mode, specifically as follows:

1. in the bridgeless rectification working mode, when the PFC control unit 40 detects that the ac voltage is low, the PFC control unit 40 closes the selection switch K to enter the bridgeless rectification working mode. As shown in fig. 3, in the positive half cycle of the sine wave, the AC input passes through D1 and is filtered by Ci1 to supply power to the 1 st and 2 nd ports of the PFC converter unit 30, the 1 st port is a positive electrode, the 2 nd port is a negative electrode, the Q1 and D5 high-frequency switches in the positive buck converter operate, and the L1 stores and discharges energy and is filtered by Co1 to form an output voltage Vo 1; in the process of the negative half cycle of the sine wave, the AC input passes through D3 and is filtered by Ci2 to supply power to the 2 nd and 3 rd ports of the PFC conversion unit 30, the 2 nd port is a positive electrode, the 3 rd port is a negative electrode, the Q2 and D6 high-frequency switches in the negative buck converter work, and the L2 stores and discharges energy and forms an output voltage Vo2 after being filtered by Co 2. Namely, the wide-voltage hybrid PFC converter works in a time-sharing mode when the K is closed, and Ci1 and Ci2 are charged by AC input voltage in each half power frequency period.

Because D2, D4 do not work in the whole process to work in no bridge rectification mode of operation, input rectifier diode conduction loss can reduce half, improve whole conversion efficiency.

2. When the PFC control unit 40 detects that the ac voltage is high, the PFC control unit 40 turns off the selection switch K to enter the bridge rectification operating mode. As shown in fig. 3, in the positive half cycle of the sine wave, the AC input passes through D1 and D4, and is filtered by Ci1 and Ci2 in series to supply power to the 1 st and 3 rd ports, the 1 st port is the positive electrode, the 3 rd port is the negative electrode, the Q1 and D5 high-frequency switches in the positive buck converter operate, and the L1 stores and discharges energy and is filtered by Co1 to form an output voltage Vo 1; meanwhile, Q2 and D6 in the negative Buck Buck converter also work in a high-frequency switch mode, and L2 stores and discharges energy and forms output voltage Vo2 after being filtered by Co 2; in the process of the sine wave negative half cycle, AC input passes through D2 and D3 and is also filtered in series by Ci1 and Ci2 to supply power to the 1 st port and the 3 rd port, the 1 st port is a positive electrode, the 3 rd port is a negative electrode, and the working process of the positive and negative symmetrical buck converter is completely the same as that of the sine wave positive half cycle.

That is, only the 1 st port and the 3 rd port of the PFC converter unit 30 work when K is off, and Ci1 and Ci2 are simultaneously charged in series by the AC input voltage in each power frequency cycle. In the process, D1, D2, D3 and D4 all work so as to work in a PFC bridge rectification mode, and the power loss and the conversion efficiency are similar to those of a traditional Boost PFC converter.

It should be noted that the two positive and negative buck converters can be operated by either synchronous or asynchronous high-frequency switching.

In order to adapt to a wider alternating current input voltage range, the selection switch K of the scheme has two states of closing and opening, and the PFC converter works in a bridgeless rectification mode and a bridge rectification mode respectively, so that the hybrid PFC converter is formed. Because the circuit is provided with the selection switch K, the voltages of the 1 st port and the 3 rd port of the PFC conversion unit 30 are basically unchanged when different alternating current input voltages are input, and the input current of the bridgeless rectification mode when alternating current low voltage is input and the input current of the bridgeless rectification mode when alternating current high voltage is input are basically maintained unchanged, the whole conversion efficiency can be improved. When the alternating current is input at low voltage, the selection switch is kept closed, the working condition of the internal power device is basically similar to that of the alternating current input at high voltage, and the voltage, the current and the power level of the power device do not need to be increased, so that the cost of components can be reduced.

Referring to fig. 3, the PFC controller of the present scheme includes a voltage error amplifier U1, a comparator U2, a PWM comparator U3, and a flip-flop U4. It should be noted that, when the Buck converter is used in a PFC circuit, according to different amplitudes of output voltage, an intermittent phenomenon exists in input ac current, so that PF is reduced, THD is increased, and therefore, the Buck PFC converter needs to be designed reasonably to achieve the desired PFC performance. The PFC controller can use primary side modulation (PSR) and secondary side modulation (SSR) for regulation, and the specific mode is that a feedback signal Vos is formed by sampling an output voltage Vo and then enters the negative electrode of a voltage error amplifier U1 of a PFC control unit 40, a voltage reference Vr1 is connected with the positive electrode of U1, and the voltage reference Vos and the voltage reference Vr1 are compared and pass through a proportional-integral-derivative (PID) compensator to form a voltage error signal and then enter the positive electrode of a comparator U2. The detected positive and negative Buck inductive currents iL1 and iL2 are converted into voltage signals, and the voltage signals are gated by diodes Di1 and Di2, enter the negative pole of U2 to control peak currents of L1 and L2, are compared with a voltage error signal, enter the positive pole of a PWM comparator U3, are compared with a standard sawtooth wave signal Vramp connected with the negative pole of U3, and enter the R end of a trigger U4. Meanwhile, the voltage signals of the drain electrode of the Q1 and the source electrode of the Q2 are detected and gated by diodes Dv1 and Dv2 to enter the S end of the U4. The R end of the trigger U4 controls the stop pulse output in real time, and the S end controls the start pulse output in real time, so that two paths of independent PWM switch driving signals are generated to respectively control the on and off of the switching tubes Q1 and Q2. The current critical conduction mode (CRM or BCM) control strategy can not only control Vo in a closed loop mode, but also realize that the input current and the input voltage are sine waves with the same frequency and the same phase so as to achieve power factor correction and higher power factor and realize zero pollution to a power grid. In addition, only the iL1 or iL2 and the Q1 or Q2 drain and source voltage signals can be detected to generate two paths of identical PWM switch driving signals, so that the working characteristics of the converter are not influenced. It should be noted that, the control strategy of this buck converter may also adopt a discontinuous current conduction mode (DCM), a DCM with a multiplier, a CRM, or even different control modes such as a continuous Current Conduction Mode (CCM), a single cycle, a charge pump, a PWM, a frequency conversion mode, etc., without affecting the control effect of the system.

The third embodiment:

referring to fig. 1 and 4, the present invention provides a wide voltage hybrid PFC converter, including an AC input unit 10, a rectifying unit 20, a first input filter capacitor Ci1, a first output filter capacitor Co1, a second input filter capacitor Ci2, a second output filter capacitor Co2, a selector switch K, PFC converting unit 30 and a PFC control unit 40.

In the present embodiment, the AC input unit 10, the rectifying unit 20, the first input filter capacitor Ci1, the first output filter capacitor Co1, the second input filter capacitor Ci2, the second output filter capacitor Co2, the selection switch K, and the PFC control unit 40 are the same as those of the second embodiment, and a description thereof will not be repeated.

Referring to fig. 4, unlike the second embodiment, in the present embodiment, the PFC converter unit 30 includes a first power switch Q1, a first body diode DQ1, a first rectifier diode D5, a first filter inductor L1, a second power switch Q2, a second body diode DQ2, a second rectifier diode D6, and a second filter inductor L2.

As shown in fig. 4, a first end of the first smoothing inductor L1 is connected to a first input end of the PFC converter unit 30, a second end of the first smoothing inductor L1 is connected to an anode of the first rectifying diode D5, a D-pole of the first power switch Q1, and a cathode of the first body diode DQ1, a cathode of the first rectifying diode D5 is connected to a first output end of the PFC converter unit 30, and a G-pole of the first power switch Q1 is connected to a modulation end of the PFC control unit 40; a first end of the second smoothing inductor L2 is connected to the second input end of the PFC converter unit 30, a second end of the second smoothing inductor L2 is connected to a negative electrode of a second rectifier diode D6, an S electrode of a second power switch Q2 and an anode of a second body diode DQ2, an anode of the second rectifier diode D6 is connected to the second output end of the PFC converter unit 30, and a G electrode of the second power switch Q2 is connected to the modulation end of the PFC control unit 40; the S pole of the first power switch Q1, the anode of the first body diode DQ1, the D pole of the second power switch Q2, and the cathode of the second body diode DQ2 are connected to the first connection terminal and the second connection terminal of the PFC converter unit 30.

In the present embodiment, the PFC converter unit 30 uses a positive-negative symmetric Boost converter (Boost), as shown in fig. 4. The positive and negative symmetrical Boost converter contains a positive Boost converter and a negative Boost converter. The positive Boost converter comprises a first power switch tube Q1, a first body diode DQ1, a first filter inductor L1 and a first rectifier diode D5, and the output end of the positive Boost converter is used as a first positive output voltage Vo 1; the negative Boost converter comprises a power switch tube Q2, a body diode DQ2 of the power switch tube Q2, a second filter inductor L2 and a second rectifier diode D6, and the output end of the negative Boost converter serves as a second positive output voltage Vo 2. When in use, the 1 st and 3 rd ports of the PFC converter unit 30 are the input positive and negative electrodes, and the 2 nd port is connected to the midpoint of the input filter capacitors Ci1 and Ci 2. The 4 th and 6 th ports of the PFC conversion unit 30 are output positive and negative electrodes, and the 5 th port is connected to the midpoint of the output filter capacitors Co1 and Co2 and connected to the 2 nd port of the PFC conversion unit 30. The high-frequency switches Q1 and D5 in the positive Boost converter work, and the stored energy and the discharge of L1 form a first output voltage Vo1 between the 4 th port and the 5 th port; meanwhile, Q2 and D6 in the negative Boost converter also work in a high-frequency switch mode, and the stored energy and the discharged energy of L2 form a second output voltage Vo2 between the 5 th port and the 6 th port. It should be noted that the two positive and negative Boost converters can work with a synchronous high-frequency switch and a non-synchronous high-frequency switch.

The fourth embodiment:

referring to fig. 1 and 5, the present invention provides a wide voltage hybrid PFC converter. In this embodiment, on the basis of the third embodiment, the PFC converter unit 30 further includes a third power switch Q3, a third body diode DQ3, a fourth power switch Q4, and a fourth body diode DQ 4.

As shown in fig. 5, the D pole and S pole of the third power switch Q3 and the positive pole and negative pole of the third body diode DQ3 are respectively connected to the negative poles of the two rectifier bridge diodes at the positive output end of the rectifier unit 20, such as the negative poles of D1 and D2 shown in fig. 5; the D pole and the S pole of the fourth power switch Q4 and the positive pole and the negative pole of the fourth body diode DQ4 are respectively connected to the positive poles of two rectifier bridge diodes at the negative output end of the rectifier unit 20, such as the positive poles of D3 and D4 shown in fig. 5; the G poles of the third power switch Q3 and the fourth power switch Q4 are connected to the modulation terminal of the PFC control unit 40.

In the present embodiment, the PFC converter unit 30 includes a two-transistor positive Buck-Boost converter and a two-transistor negative Buck-Boost converter. The double-tube positive Buck-Boost converter comprises a power switch tube Q1 and a body diode DQ1 thereof, a power switch tube Q3 and a body diode DQ3 thereof, a Buck-Boost inductor L1, rectifier diodes D2 and D5, and the output end of the double-tube positive Buck-Boost converter is used as a first positive output voltage Vo 1. This circuit is time-sharing: the Buck converter is composed of Q3, D2 and L1, the Boost converter is composed of Q1, D5 and L1, and the Buck converter works in a Buck state when the AC input voltage is high; and when the AC input voltage is low, the circuit works in a Boost state. The double-tube negative Buck-Boost converter comprises a power switch tube Q2 and a body diode DQ2 thereof, a power switch tube Q4 and a body diode DQ4 thereof, a Buck-Boost inductor L2, rectifier diodes D4 and D6, and the output end of the double-tube negative Buck-Boost converter is used as a second positive output voltage Vo 2. The circuit also works in a time-sharing mode, and the working principle of the circuit is similar to that of a double-tube positive Buck-Boost converter.

The operation of the positive-negative symmetrical double-tube Buck-Boost Buck-Boost PFC converter is similar to that of the second embodiment, and the description is not repeated here. The double-tube Buck-Boost converter is an improved form of the traditional single-tube Buck-Boost converter, the power switch tubes and the rectifier diodes have the advantages of lower voltage stress and the like, and the double-tube Buck-Boost converter can also be used in a PFC converter, but four power switch tubes are required.

It should be noted that the two positive and negative Boost converters can work with a synchronous high-frequency switch and a non-synchronous high-frequency switch. In addition, in the embodiment, the double-tube Buck-Boost Buck-Boost PFC converter works in the bridgeless rectification mode no matter the selection switch K is in a closed state or an open state, so that the overall conversion efficiency is improved, and the cost of a power device is reduced.

Fifth embodiment:

referring to fig. 1 and 6, the present invention provides a wide voltage hybrid PFC converter, including an AC input unit 10, a rectifying unit 20, a first input filter capacitor Ci1, a first output filter capacitor Co1, a second input filter capacitor Ci2, a second output filter capacitor Co2, a selector switch K, PFC converting unit 30 and a PFC control unit 40.

Referring to fig. 6, in the present embodiment, the PFC converter unit 30 includes a first power switch Q1, a first body diode DQ1, a first rectifier diode D5, a first smoothing inductor L1, a second power switch Q2, a second body diode DQ2, a second rectifier diode D6, and a second smoothing inductor L2.

Referring to fig. 6, in this embodiment, the D pole of the first power switch Q1 and the negative pole of the first body diode DQ1 are connected to the first input terminal of the PFC converter unit 30, the G pole of the first power switch Q1 is connected to the modulation terminal of the PFC control unit 40, the S pole of the first power switch Q1 and the positive pole of the first body diode DQ1 are connected to the negative pole of the first rectifier diode D5 and the first terminal of the first smoothing inductor L1, and the positive pole of the first rectifier diode D5 is connected to the first output terminal of the PFC converter unit 30. The D pole of the second power switch Q2 and the negative pole of the second body diode DQ2 are connected to the second input end of the PFC converter unit 30, the G pole of the second power switch Q2 is connected to the modulation end of the PFC control unit 40, the S pole of the second power switch Q2 and the positive pole of the second body diode DQ2 are connected to the positive pole of the second rectifier diode D6 and the first end of the second smoothing inductor L2, and the negative pole of the second rectifier diode D6 is connected to the second output end of the PFC converter unit 30; the second ends of the first filter inductor L1 and the second filter inductor L2 are connected to the first connection end and the second connection end of the PFC converter unit 30.

In the present embodiment, the PFC converter unit 30 uses a positive-negative symmetric Buck-Boost converter (Buck-Boost), as shown in fig. 6. The positive and negative symmetrical Buck-Boost converter comprises a positive Buck-Boost converter and a negative Buck-Boost converter: the positive Buck-Boost converter comprises a first power switch tube Q1, a first body diode DQ1, a first filter inductor L1 and a first rectifier diode D5, and the output end of the positive Buck-Boost converter serves as a first positive output voltage Vo 1. The negative Buck-Boost converter comprises a second power switch tube Q2, a second body diode DQ2, a second filter inductor L2 and a second rectifier diode D6, and the output end of the negative Buck-Boost converter serves as a second positive output voltage Vo 2.

When the PFC conversion unit works, the 1 st port and the 3 rd port of the PFC conversion unit 30 are input positive and negative electrodes, the 2 nd port is connected to the midpoint of the input filter capacitors Ci1 and Ci2, the 4 th port and the 6 th port are output positive and negative electrodes, and the 5 th port is connected to the midpoint of the output filter capacitors Co1 and Co2 and is connected with the 2 nd port. Q1, D5 high frequency switch work in the positive Buck-Boost converter, and the first output voltage Vo1 is formed between the 4 th port and the 5 th port by the stored energy and the discharge of L1; meanwhile, Q2 and D6 in the negative Buck-Boost converter also work in a high-frequency switch mode, and the stored energy and the discharged energy of L2 form a second output voltage Vo1 between the 5 th port and the 6 th port.

It should be understood that, as long as the present invention uses two positive and negative symmetrical circuits inside the PFC converter unit 30, the PFC converter unit 30 may also use other various conventional standard or novel non-isolated topologies, including but not limited to Cuk, SEPIC, Zeta converter, etc., which are not described one by one here.

Sixth embodiment:

referring to fig. 1 and 7, the present invention provides a wide voltage hybrid PFC converter, including an AC input unit 10, a rectifying unit 20, a first input filter capacitor Ci1, a first output filter capacitor Co1, a second input filter capacitor Ci2, a second output filter capacitor Co2, a selector switch K, PFC converting unit 30 and a PFC control unit 40.

Referring to fig. 7, in the present embodiment, the PFC converter unit 30 uses an isolation topology. Specifically, the PFC converter unit 30 includes a first power switch Q1, a first body diode DQ1, a first rectifier diode D5, a first flyback transformer T1, a second power switch Q2, a second body diode DQ2, a second rectifier diode D6, and a second flyback transformer T2.

Referring to fig. 7, a first end of a primary winding of a first flyback transformer T1 is connected to a first input terminal of the PFC converter unit 30, a second end of the primary winding of the first flyback transformer T1 is connected to a D terminal of a first power switch Q1 and a negative terminal of a first body diode DQ1 thereof, a G terminal of the first power switch Q1 is connected to a modulation terminal of the PFC control unit 40, an S terminal of the first power switch Q1 and a positive terminal of a first body diode DQ1 thereof are connected to a first connection terminal of the PFC converter unit 30, an output positive terminal of a secondary winding of the first flyback transformer T1 is connected to a positive terminal of the first rectifier diode D5, a negative terminal of the first rectifier diode D5 is connected to a first output terminal of the PFC converter, and an output negative terminal of the secondary winding of the first flyback transformer T1 is connected to a second connection terminal of the PFC converter unit 30; an S pole of the second power switch Q2 and an anode of the second body diode DQ2 are connected to the second input terminal of the PFC control unit 40, a G pole of the second power switch Q2 is connected to the modulation terminal of the PFC control unit 40, a D pole of the second power switch Q2 and a cathode of the second body diode DQ2 are connected to the first terminal of the primary winding of the second flyback transformer T2, the second terminal of the primary winding of the flyback transformer is connected to the first connection terminal of the PFC conversion unit, an output anode of the secondary winding of the flyback transformer is connected to an anode of the second rectifier diode D6, a cathode of the second rectifier diode D6 is connected to the second connection terminal of the PFC conversion unit 30, and an output cathode of the secondary winding of the flyback transformer is connected to the second output terminal of the PFC conversion unit 30.

In the present embodiment, the PFC conversion unit 30 includes a positive Flyback converter and a negative Flyback converter. The positive Flyback converter comprises a first power switch tube Q1, a first body diode DQ1, a first Flyback transformer T1 and a first rectifier diode D5, and the output end of the positive Flyback converter is used as a first positive output voltage Vo 1. The negative Flyback converter comprises a second power switch tube Q2, a second body diode DQ2, a second Flyback transformer T2 and a second rectifier diode D6, and the output end of the negative Flyback converter is used as a second positive output voltage Vo 2.

The 1 st and 3 rd ports of the PFC conversion unit 30 are input positive and negative electrodes, the 2 nd port is connected to the midpoint of the input filter capacitors Ci1 and Ci2, the 4 th and 6 th ports are output positive and negative electrodes, and the 5 th port is connected to the midpoint of the output filter capacitors Co1 and Co2, so that the safety isolation between the output side and the input side can be realized. The Q1 and D5 high-frequency switches in the positive Flyback converter work, and the T1 energy storage and discharge form a first output voltage Vo1 between the 4 th port and the 5 th port; meanwhile, Q2 and D6 in the negative Flyback converter also work in a high-frequency switch mode, and the energy storage and discharge of T2 form a second output voltage Vo2 between the 5 th port and the 6 th port. The output voltage Vo1 and the output voltage Vo2 are connected in series, and are suitable for application occasions with larger output voltage.

Seventh embodiment:

referring to fig. 1 and 8, the present invention provides a wide voltage hybrid PFC converter, including an AC input unit 10, a rectifying unit 20, a first input filter capacitor Ci1, a first output filter capacitor Co1, a second input filter capacitor Ci2, a second output filter capacitor Co2, a selector switch K, PFC converting unit 30 and a PFC control unit 40.

Referring to fig. 8, in the present embodiment, the PFC converter unit 30 includes a first power switch Q1, a first body diode DQ1, a first rectifier diode D5, a first flyback transformer T1, a second power switch Q2, a second body diode DQ2, a second rectifier diode D6, and a second flyback transformer T2.

Referring to fig. 8, a first end of a primary winding of a first flyback transformer T1 is connected to a first input terminal of the PFC converter unit 30, a second end of the primary winding of the first flyback transformer T1 is connected to a D terminal of a first power switch Q1 and a negative terminal of a first body diode DQ1 thereof, a G terminal of the first power switch Q1 is connected to a modulation terminal of the PFC control unit 40, an S terminal of the first power switch Q1 and a positive terminal of the first body diode DQ1 thereof are connected to a first connection terminal of the PFC converter unit 30, an output positive terminal of a secondary winding of the first flyback transformer T1 is connected to a positive terminal of the first rectifier diode D5, a negative terminal of the first rectifier diode D5 is connected to a first output terminal of the PFC converter, and an output negative terminal of the secondary winding of the first flyback transformer T1 is connected to a second output terminal of the PFC converter unit 30; the S pole of the second power switch Q2 and the positive pole of the second body diode DQ2 are connected to the second input end of the PFC control unit 40, the G pole of the second power switch Q2 is connected to the modulation end of the PFC control unit 40, the D pole of the second power switch Q2 and the negative pole of the second body diode DQ2 are connected to the first end of the primary winding of the second flyback transformer T2, the second end of the primary winding of the flyback transformer is connected to the first connection end of the PFC conversion unit, the output positive pole of the secondary winding of the flyback transformer is connected to the positive pole of the second rectifier diode D6, the negative pole of the second rectifier diode D6 is connected to the first output end of the PFC conversion unit 30, and the output negative pole of the secondary winding of the flyback transformer is connected to the second output end of the PFC conversion unit 30.

In the present embodiment, the PFC converter unit 30 also uses a Flyback converter (Flyback), as shown in fig. 8. The PFC converter unit 30 includes a positive Flyback converter and a negative Flyback converter. The positive Flyback converter comprises a first power switch tube Q1, a first body diode DQ1, a first Flyback transformer T1 and a first rectifier diode D5, and the output end of the positive Flyback converter is used as a first positive output voltage Vo 1; the negative Flyback converter comprises a second power switch tube Q2, a second body diode DQ2, a second Flyback transformer T2 and a second rectifier diode D6, and the output end of the negative Flyback converter is used as a second positive output voltage Vo 2.

The 1 st and 3 rd ports of the PFC conversion unit 30 are input positive and negative electrodes, the 2 nd port is connected to the midpoint of the input filter capacitors Ci1 and Ci2, the 4 th and 6 th ports are output positive and negative electrodes, and the 5 th port is suspended without connecting any device, so that the safety isolation between the output side and the input side can be realized. The Q1 and D5 high-frequency switches in the positive Flyback converter work, and the T1 energy storage and discharge form a first output voltage Vo1 between the 4 th port and the 6 th port; meanwhile, Q2 and D6 in the negative Flyback converter also work in a high-frequency switch mode, and the stored energy and the discharged energy of the T2 form a second output voltage Vo2 between the 4 th port and the 6 th port. The output voltage Vo1 and the output voltage Vo2 are connected in parallel, and are suitable for application occasions with large output current.

Eighth embodiment:

the utility model discloses still provide a switching power supply, include as in any embodiment wide voltage hybrid PFC converter.

The utility model provides a pair of switching power supply, including wide voltage hybrid PFC converter. The wide-voltage hybrid PFC converter is composed of a PFC conversion unit 30, a selection switch and a PFC control unit 40, wherein the PFC conversion unit 30 realizes power conversion, the selection switch is switched on and off according to the size of alternating-current voltage so as to adapt to a wide alternating-current input voltage range, and the size of input current is basically kept unchanged, wherein when the selection switch is switched off, the PFC conversion unit 30 works in a bridgeless rectification mode, so that the overall conversion efficiency can be improved; in addition, the PFC control unit 40 is matched with a selection switch, so that high power factor and low current harmonic can be realized; in addition, the power device adopted by the scheme does not need to increase the voltage, the current and the power level, so that the cost of components can be reduced.

The technical content of the present invention is further described by the embodiments only, so that the reader can understand it more easily, but the embodiments of the present invention are not limited thereto, and any technical extension or re-creation according to the present invention is protected by the present invention. The protection scope of the present invention is subject to the claims.

Claims

1. A wide-voltage hybrid PFC converter is characterized by comprising an AC input unit, a rectifying unit, a first input filter capacitor, a first output filter capacitor, a second input filter capacitor, a second output filter capacitor, a selection switch, a PFC conversion unit and a PFC control unit; the alternating current output end of the AC input unit is electrically connected with the alternating current input end of the rectifying unit, the first output end of the rectifying unit is connected with the first end of the first input filter capacitor and the first input end of the PFC conversion unit, the second output end of the rectifying unit is connected with the first end of the second input filter capacitor and the second input end of the PFC conversion unit, the first end of the selector switch is connected with the second end of the first input filter capacitor, the second end of the second input filter capacitor and the first connection end of the PFC conversion unit, and the second end of the selector switch is connected with the alternating current input end of the rectifying unit; the first output end of the PFC conversion unit is connected with the first output filter capacitor and the first end of the load, the second output end of the PFC conversion unit is connected with the first end of the second output filter capacitor and the second end of the load, the second ends of the first output filter capacitor and the second output filter capacitor are connected with the second connecting end of the PFC conversion unit, and the first connecting end and the second connecting end of the PFC conversion unit are communicated; the control end of the PFC control unit is connected with the controlled end of the selection switch, the first sampling end of the PFC control unit is connected with the first input end or the second output end of the PFC conversion unit and is used for sampling the input voltage of the PFC conversion unit, the second sampling end of the PFC control unit is connected with the first output end or the second output end of the PFC conversion unit and is used for sampling the output voltage of the PFC conversion unit, and the modulation end of the PFC control unit is connected with the PFC conversion unit.

2. The wide voltage hybrid PFC converter according to claim 1, wherein the rectifying unit comprises 4 rectifying bridge diodes, the 4 rectifying bridge diodes are connected to form a bridge rectifying circuit, and two AC output terminals of the AC input unit are respectively connected to two AC input terminals of the bridge rectifying circuit.

3. The wide voltage hybrid PFC converter of claim 2, wherein the PFC conversion unit comprises a first power switch tube, a first body diode thereof, a first rectifier diode, a first filter inductor, a second power switch tube, a second body diode thereof, a second rectifier diode, and a second filter inductor; the D pole of the first power switch tube and the negative pole of the first body diode of the first power switch tube are connected with the first input end of the PFC conversion unit, the G pole of the first power switch tube is connected with the modulation end of the PFC control unit, the S pole of the first power switch tube and the positive pole of the first body diode of the first power switch tube are connected with the negative pole of the first rectifier diode and the first end of the first filter inductor, and the second end of the first filter inductor is connected with the first output end of the PFC conversion unit; the S pole of the second power switch tube and the anode of the second body diode of the second power switch tube are connected with the second input end of the PFC conversion unit, the G pole of the second power switch tube is connected with the modulation end of the PFC control unit, the D pole of the second power switch tube and the cathode of the second body diode of the second power switch tube are connected with the anode of the second rectifier diode and the first end of the second filter inductor, and the second end of the second filter inductor is connected with the second output end of the PFC conversion unit; the anode of the first rectifying diode and the cathode of the second rectifying diode are connected with the first connecting end and the second connecting end of the PFC conversion unit.

4. The wide voltage hybrid PFC converter of claim 2, wherein the PFC conversion unit comprises a first power switch tube, a first body diode thereof, a first rectifier diode, a first filter inductor, a second power switch tube, a second body diode thereof, a second rectifier diode, and a second filter inductor; the first end of the first filter inductor is connected with the first input end of the PFC conversion unit, the second end of the first filter inductor is connected with the anode of the first rectifier diode, the D pole of the first power switch tube and the cathode of the first body diode, the cathode of the first rectifier diode is connected with the first output end of the PFC conversion unit, and the G pole of the first power switch tube is connected with the modulation end of the PFC control unit; the first end of the second filter inductor is connected with the second input end of the PFC conversion unit, the second end of the second filter inductor is connected with the cathode of the second rectifier diode, the S pole of the second power switch tube and the anode of the second body diode, the anode of the second rectifier diode is connected with the second output end of the PFC conversion unit, and the G pole of the second power switch tube is connected with the modulation end of the PFC control unit; the S pole of the first power switch tube, the anode of the first body diode, the D pole of the second power switch tube and the cathode of the second body diode are connected with the first connection end and the second connection end of the PFC conversion unit.

5. The wide voltage hybrid PFC converter of claim 4, wherein the PFC conversion unit further comprises a third power switch tube, a third body diode thereof, a fourth power switch tube and a fourth body diode thereof; the D pole and the S pole of the third power switch tube and the anode and the cathode of the third body diode are respectively connected with the cathodes of the two rectifier bridge diodes at the positive output end of the rectifier unit; the D pole and the S pole of a fourth power switch tube and the anode and the cathode of a fourth body diode of the fourth power switch tube are respectively connected with the anodes of the two rectifier bridge diodes at the negative output end of the rectifier unit; g poles of the third power switch tube and the fourth power switch tube are connected with the modulation end of the PFC control unit.

6. The wide voltage hybrid PFC converter of claim 2, wherein the PFC conversion unit comprises a first power switch tube, a first body diode thereof, a first rectifier diode, a first filter inductor, a second power switch tube, a second body diode thereof, a second rectifier diode, and a second filter inductor; the D pole of the first power switch tube and the negative pole of the first body diode of the first power switch tube are connected with the first input end of the PFC conversion unit, the G pole of the first power switch tube is connected with the modulation end of the PFC control unit, the S pole of the first power switch tube and the positive pole of the first body diode of the first power switch tube are connected with the negative pole of the first rectifier diode and the first end of the first filter inductor, and the positive pole of the first rectifier diode is connected with the first output end of the PFC conversion unit; the D pole of the second power switch tube and the negative pole of the second body diode of the second power switch tube are connected with the second input end of the PFC conversion unit, the G pole of the second power switch tube is connected with the modulation end of the PFC control unit, the S pole of the second power switch tube and the positive pole of the second body diode of the second power switch tube are connected with the positive pole of the second rectifier diode and the first end of the second filter inductor, and the negative pole of the second rectifier diode is connected with the second output end of the PFC conversion unit; and the second ends of the first filter inductor and the second filter inductor are connected with the first connecting end and the second connecting end of the PFC conversion unit.

7. The wide voltage hybrid PFC converter of claim 2, wherein the PFC conversion unit comprises a first power switch tube, a first body diode thereof, a first rectifier diode, a first flyback transformer, a second power switch tube, a second body diode thereof, a second rectifier diode, and a second flyback transformer; the first end of a primary winding of a first flyback transformer is connected with the first input end of the PFC conversion unit, the second end of the primary winding of the first flyback transformer is connected with the D pole of a first power switch tube and the cathode of a first body diode of the first power switch tube, the G pole of the first power switch tube is connected with the modulation end of the PFC control unit, the S pole of the first power switch tube and the anode of the first body diode of the first power switch tube are connected with the first connection end of the PFC conversion unit, the output anode of the secondary winding of the first flyback transformer is connected with the anode of a first rectifier diode, the cathode of the first rectifier diode is connected with the first output end of the PFC converter, and the output cathode of the secondary winding of the first flyback transformer is connected with the second connection end of the PFC conversion unit; the S pole of the second power switch tube and the anode of the second body diode of the second power switch tube are connected with the second input end of the PFC control unit, the G pole of the second power switch tube is connected with the modulation end of the PFC control unit, the D pole of the second power switch tube and the cathode of the second body diode of the second power switch tube are connected with the first end of the primary winding of the second flyback transformer, the second end of the primary winding of the flyback transformer is connected with the first connection end of the PFC conversion unit, the output anode of the secondary winding of the flyback transformer is connected with the anode of the second rectifier diode, the cathode of the second rectifier diode is connected with the second connection end of the PFC conversion unit, and the output cathode of the secondary winding of the flyback transformer is connected with the second output end of the PFC conversion unit.

8. The wide voltage hybrid PFC converter of claim 2, wherein the PFC conversion unit comprises a first power switch tube, a first body diode thereof, a first rectifier diode, a first flyback transformer, a second power switch tube, a second body diode thereof, a second rectifier diode, and a second flyback transformer; the first end of a primary winding of a first flyback transformer is connected with the first input end of the PFC conversion unit, the second end of the primary winding of the first flyback transformer is connected with the D pole of a first power switch tube and the cathode of a first body diode of the first power switch tube, the G pole of the first power switch tube is connected with the modulation end of the PFC control unit, the S pole of the first power switch tube and the anode of the first body diode of the first power switch tube are connected with the first connection end of the PFC conversion unit, the output anode of the secondary winding of the first flyback transformer is connected with the anode of a first rectifier diode, the cathode of the first rectifier diode is connected with the first output end of the PFC converter, and the output cathode of the secondary winding of the first flyback transformer is connected with the second output end of the PFC conversion unit; the S pole of the second power switch tube and the anode of the second body diode of the second power switch tube are connected with the second input end of the PFC control unit, the G pole of the second power switch tube is connected with the modulation end of the PFC control unit, the D pole of the second power switch tube and the cathode of the second body diode of the second power switch tube are connected with the first end of the primary winding of the second flyback transformer, the second end of the primary winding of the flyback transformer is connected with the first connection end of the PFC conversion unit, the output anode of the secondary winding of the flyback transformer is connected with the anode of the second rectifier diode, the cathode of the second rectifier diode is connected with the first output end of the PFC conversion unit, and the output cathode of the secondary winding of the flyback transformer is connected with the second output end of the PFC conversion unit.

9. The wide voltage hybrid PFC converter of claim 1, wherein the AC input unit comprises an EMI filter inductor and an EMI filter capacitor.

10. A switching power supply comprising a wide voltage hybrid PFC converter according to any one of claims 1 to 9.