TWI614978B - Single-phase bridgeless isolated power factor adjustment circuit - Google Patents

Abstract

The utility model relates to a single-phase bridgeless isolated power factor adjusting circuit, which comprises an EMI filter module, a low frequency switching diode module, two switches and two isolated voltage conversion modules, and the EMI filter module is coupled to the AC power source. The low frequency switching diode module is coupled to the EMI filter module, the two switches are coupled to the low frequency switching diode module, and the two isolated voltage conversion modules are respectively coupled to one of the two switches. Wherein, the low frequency switching diode module can be in the first or second conducting state, and corresponding to different conducting states, one of the two switches is turned on and the first isolated voltage converting mode is turned on. With the above circuit configuration, the single-phase bridgeless isolation power factor adjustment circuit of the invention can achieve advantages such as difficulty in failure, simple circuit, cost saving, small size, and high conversion efficiency.

Description

Single-phase bridgeless isolated power factor adjustment circuit

The present invention relates to a power factor adjusting circuit, and more particularly to a single phase isolated power factor adjusting circuit.

As shown in FIG. 1, the conventional single-phase high-power switching power supply 1000 has a two-stage circuit architecture. The front stage is a non-isolated PFC rectifier 1100, and the latter stage is an isolated DC-to-DC converter. 1200. 2 and 3 are respectively a conventional switching power supply 2000, 3000, FIG. 2 is a PFC boost AC-DC rectifier 2100 combined with a full bridge phase shift DC-DC converter 2200, and FIG. 3 is a boost type. The AC-DC rectifier 3100 incorporates an LLC resonant DC-DC converter 3200. The switched power supplies 2000, 3000 of Figures 2 and 3 are suitable for AC power supply S _AC and load load.

However, the conventional PFC circuit has the following disadvantages: (1) If the switching power supply has a bridge rectifier, the conduction loss is high. (2) In the switching power supply that does not currently have a bridge rectifier, the circuit architecture of the switching power supply is a transformerless circuit architecture. (3) The boost type PFC converter has a large capacitance on the DC output side, so the AC voltage input instantaneously charges the DC capacitor, which is likely to cause a relatively high input current, resulting in a commutator failure or an output diode failure, and is also easily The charging is too high and the main power component is damaged. (4) In the control system of the switching power supply, the power factor is controlled on the primary side, and the DC-to-DC converter is controlled on the secondary side, so the first and second sides must be separated. The control system operates smoothly and complicates the circuit.

Therefore, there is a need for an isolated PFC circuit architecture that addresses the shortcomings of the conventional PFC circuits described above.

In order to solve the above problems of the prior art, an object of the present invention is to provide a single-phase bridgeless isolated power factor adjustment circuit, which has low conduction loss, is not easy to malfunction, has simple circuit, saves cost, has small volume, and has high conversion efficiency. advantage.

To achieve the above and other objects, the present invention provides a single-phase bridgeless isolated power factor adjustment circuit including an EMI filter module, a low frequency switching diode module, a first switch, and a second switch. a first isolated voltage conversion module and a second isolated voltage conversion module.

The EMI filter module is coupled to an external AC power supply; the low frequency switching diode module is coupled to the EMI filter module; the first switch and the second switch are coupled to the low frequency switching diode The first isolated voltage conversion module is coupled to the first switch; and the second isolated voltage conversion module is coupled to the second switch.

When the low frequency switching diode module is in the first conducting state, the first switch is turned on and the first isolated voltage conversion module is turned on, when the low frequency switching diode module is in the second conducting state. The second switch is turned on and the second isolated voltage conversion module is turned on.

In the single-phase bridgeless isolated power factor adjustment circuit, the low frequency switching diode module includes a first single-flow diode unit and a second single-flow diode unit, and the second single-flow diode unit When the polar body unit is turned on and the first single current is turned off to the diode unit, the first conductive state is defined. When the first single current is turned on to the diode unit and the second single current is turned off to the diode unit, it is defined as The second conduction state.

In the single-phase bridgeless isolation power factor adjustment circuit, the first single-flow diode unit and the second single-flow diode unit are alternately turned on, so that the low-frequency switching diode module is switched to the first The on state and the second on state.

In the above-mentioned single-phase bridgeless power factor adjustment circuit, the EMI filter module includes a first inductor, a second inductor, and a first capacitor, and one end of the first inductor is coupled to one end of the AC power source. One end of the second inductor is coupled to the other end of the AC power source; and the two ends of the first capacitor are respectively coupled to the other end of the first inductor and the other end of the second inductor.

In the above single-phase bridgeless power factor adjusting circuit, the low frequency switching diode module includes a first single current diode unit and a second single current diode unit, the first single current diode The negative end of the body unit is coupled to one end of the first capacitor and the other end of the first inductor, and the second end of the second unit is coupled to the other end of the first capacitor and the second inductor The other end.

In the above-mentioned single-phase bridgeless-type power factor adjustment circuit, the first single-flow diode unit and the second-side diode unit are coupled to a first node, the first node. One end of the switch and one end of the second switch are coupled to a second node, and the first node is coupled to the second node.

In the above-mentioned single-phase bridgeless power factor adjusting circuit, the first surge absorbing module and the second swell absorbing module are coupled to the first switch and The first isolated voltage conversion module; and the second surge absorption module are coupled to the second switch and the second isolated voltage conversion module.

The first phase control module includes a first control module and a second control module, and the first control module is coupled to the gate terminal of the first switch to control the Opening and closing of the first switch; and the second control module is coupled to the gate end of the second switch to control opening and closing of the second switch.

The first control module includes a first voltage control unit, a first zero current detecting unit and a first comparing unit, and the first control module is coupled to the single-phase bridgeless power factor adjusting circuit. Connected to the output end of the first isolated voltage conversion module to obtain a first output voltage feedback signal, the first voltage control unit adjusts the first output voltage feedback signal to output a first switch current control signal, The first zero current detecting unit is coupled to the first isolated voltage converting module to output a first zero current detecting signal, and the first comparing unit compares the first switch current control signal with the first switch a voltage at one end, and outputting a first control signal according to the comparison result and the first zero current detection signal, wherein the first control signal is used to control the opening and closing of the first switch.

The second control module includes a second voltage control unit, a second zero current detecting unit and a second comparing unit, and the second control module is coupled to the single-phase bridgeless power factor adjusting circuit. Connected to the output end of the second isolated voltage conversion module to obtain a second output voltage feedback signal, the second voltage control unit adjusts the second output voltage feedback signal to output a second switch current control signal, The second zero current detecting unit is coupled to the second isolated voltage converting module to output a second zero current detecting signal, and the second comparing unit compares the second switch current control signal and the second switch The voltage of one end, and outputting a second control signal according to the comparison result and the second zero current detection signal, the second control signal is used to control the opening and closing of the second switch.

In summary, with the above circuit configuration, the single-phase bridgeless isolated power factor adjustment circuit of the present invention can achieve advantages such as difficulty in failure, simple circuit, cost saving, small size, and high conversion efficiency.

In order to fully understand the objects, features and advantages of the present invention, the present invention will be described in detail by the following specific embodiments and the accompanying drawings.

Please refer to FIG. 4 and FIG. 5A. FIG. 4 is a schematic diagram of an embodiment of a single-phase bridgeless isolated power factor adjusting circuit according to the present invention, and FIG. 5A is another embodiment of the single-phase bridgeless isolated power factor adjusting circuit of the present invention. Schematic diagram. As shown in FIG. 4 and FIG. 5A , the single-phase isolated power factor adjustment circuit includes an EMI filter module 10 , a low frequency switching diode module 20 , a first switch Q ₁ , and a second switch Q _{2 .} A first isolated voltage conversion module 30 and a second isolated voltage conversion module 40.

The EMI filter module 10 can include a first inductor L _S1 , a second inductor L _{S2 ,} and a first capacitor C _S . One end of the first inductor L _S1 is coupled to one end of an external AC power source V _S . One end of the second inductor L _S2 is coupled to the other end of the AC power source V _S , and the two ends of the first capacitor C _S are respectively coupled to the other end of the first inductor L _S1 and the second inductor L _S2 another side.

The AC power supply V _S can be a commercial power supply, and the EMI filter module 10 can be adapted to an AC power supply V _{S of a} plurality of different voltage values (for example, 110V, 220V, etc.). In FIG. 5A, the first inductance L _{S1 is} coupled. connected to the positive terminal V _S of the AC power supply, the second inductor L _S2 is coupled to the negative terminal of the AC power source V _S, but in other possible embodiments, the first inductor L _S1 may be coupled to the AC the negative terminal of the power source V _S, the second inductor L _S2 may be coupled to the positive terminal of the AC power source V _S.

The low frequency switching diode module 20 can include a first single-flow diode unit 21 and a second single-flow diode unit 22, and the first single-flow diode unit 21 can have only one single flow direction. The pole body D ₁ , but may also have two or more single-flow diodes connected in series or in parallel, and the second single-flow diode unit 22 may have only a single-flow diode D ₂ , but It is also possible to have two or more single-flow diodes and connect them in series or in parallel.

The negative end of the first single-channel diode unit 21 can be coupled to one end of the first capacitor C _S and the other end of the first inductor L _S1 , and the second single-flow to the negative end of the diode unit 22 can be The other end of the first capacitor C _{S and} the other end of the second inductor L _S2 are coupled.

The first terminal of the first switch Q ₁ and the second switch of the second switch unit 21 can be coupled to a first node Node1. Q ₂ may be an end coupled to a second node Node2, the first node Node1 may be coupled to the second node Node2.

An input end of the first isolated voltage conversion module 30 is coupled to the first switch Q ₁ , and an input end of the second isolated voltage conversion module 40 is coupled to the second switch Q ₂ , the first isolation voltage conversion module 30 may be isolated using a T _r1 coil flyback (flyback) converter, and the secondary side thereof may have a diode and a capacitor C _o1 D _o1, which has a voltage capacitor C _o1 difference V _o1, the second isolated voltage converter module 40 may also be isolated using a coil flyback (flyback) converter T _r2, and the secondary side thereof may have a diode and a capacitor C D _{o2 O2} , the capacitor C _o2 has a voltage difference V _o2 .

An external load R is coupled to the output of the first isolated voltage conversion module 30 and the output of the second isolated voltage conversion module 40. The load R has a voltage difference V _o .

In addition, the single-phase bridgeless isolation power adjustment circuit of the present invention may further include a first surge absorbing module 50 and a second surge absorbing module 60. The first surge absorbing module 50 is coupled to the The first switch Q ₁ and the first isolated voltage conversion module 30 are configured to reduce or absorb the glitch of the first switch Q ₁ , and the second spur absorption module 60 is coupled to the second switch Q ₂ and The second isolated voltage conversion module 40 is configured to reduce or absorb the glitch of the second switch Q ₂ .

In FIG. 5A, the first surge absorbing module 50 is composed of a capacitor, a resistor and a reversed diode, but this is only an embodiment of the present invention, and is not limited thereto. . The second snubber absorbing module 60 is also composed of a capacitor, a resistor, and a reversed diode. However, this is only an embodiment of the present invention, and is not limited thereto.

Furthermore, in order to reduce the conduction loss of the power component current and to eliminate the recovery current loss of the diode, the single-phase bridgeless isolation power adjustment circuit of the present invention can operate in a critical conduction mode.

Further, the present invention is a single-phase bridge isolated power factor adjusting circuit may include a first control module 70 and a second control module 80, the first control module 70 may be coupled to the first switch Q ₁ ' gate terminal to control the opening and closing of the first switch Q _1, the second control module 80 may be coupled to the gate terminal of the second switch Q ₂ to control the second switch Q ₂ of the hoist.

As shown in FIG. 5B, the first control module 70 includes a first voltage control unit 71, a first zero current detecting unit 72, and a first comparing unit 73. The first control module 70 is coupled to the first control module 70. The output end of the first isolated voltage conversion module 30 is configured to obtain a first output voltage feedback signal, and the first voltage control unit 71 adjusts the first output voltage feedback signal to output a first switch current control signal. The first zero current detecting unit 72 is coupled to the first isolated voltage converting module 30 to output a first zero current detecting signal, and the first comparing unit 73 compares the first switch current control signal with the first one end of the switch Q ₁ of voltage, and outputs a first control signal according to the comparison result and the first zero-current detection signal, the first control signal for controlling opening and closing of the first switch Q _1.

The second control module 80 includes a second voltage control unit 81, a second zero current detecting unit 82, and a second comparing unit 83. The second control module 80 is coupled to the second isolated voltage conversion. The output end of the module 40 is configured to obtain a second output voltage feedback signal, and the second voltage control unit 81 adjusts the second output voltage feedback signal to output a second switch current control signal, the second zero current detection The unit 82 is coupled to the second isolated voltage conversion module 40 to output a second zero current detection signal, and the second comparison unit 83 compares the second switch current control signal with one of the second switch Q ₂ voltage, and outputting a second control signal according to the comparison result and the second zero-current detection signal, the second control signal for controlling the second switch Q ₂ of the hoist.

Since each component in the second control module 80 substantially corresponds to each component in the first control module 70, each component in the second control module 80 can be referred to FIG. 5B. No longer.

In the first control module 70 or the second control module 80, the output voltage feedback signal _Vofb is adjusted by the voltage controller and multiplied by the rectified AC power supply voltage signal ABS(V _s ) to obtain a switching current. V _con the control _signal, controls the switching current of the sensing signal V _con V _cs1 of switch current comparator reset RS flip-flop after the switch is turned off, diode D _o1 of the secondary side of the transformer begin to release stored energy For the load R, the zero current detection (ZCD) unit uses the auxiliary coil V _aux voltage of the converter and a comparator to detect the time when the secondary side diode current I _Do1 drops to zero, and utilizes The ZCD signal sets the RS flip-flop to turn the switch on. The operating waveform of the control circuit during the positive half cycle is shown in FIG. 6.

The waveform of the voltage input by the AC power source V _S can be divided into a positive half cycle and a negative half cycle, and the working mode of the positive half cycle is as shown in FIG. 7A and FIG. 7B , and the negative half cycle working mode is as shown in FIG. 7C and FIG. 7D . 7A and 7C are energy storage modes, and FIGS. 7B and 7D are energy release modes.

In FIG. 7A, the first switch Q ₁ turns on and the first isolated voltage converter module 30 is turned on, the second switch Q ₂ and the second nonconductive isolated voltage converter module 40 is closed, at which point the single The phase-free bridge-free power factor adjustment circuit is defined as a first conduction state, and the current flows through the first inductor L _S1 , the first isolated voltage conversion module 30 , the first switch Q ₁ , and the second single The diode unit 22 and the second inductor L _S2 are formed to form a conduction path.

In FIG. 7B, the first switch Q ₁ and the second switch Q ₂ are not turned on. At this time, the first inductor L _S1 , the first capacitor C _S and the second inductor L _S2 form a conduction path. A conductive path is formed inside the first isolated voltage conversion module 30.

In FIG. 7C, the second switch Q _{2 is} turned on and the second isolated voltage conversion module 40 is turned on, the first switch Q _{1 is} not turned on, and the first isolated voltage conversion module 30 is turned off. The phase-free bridge-free power factor adjustment circuit is defined as a second conductive state, and the current flows through the second inductor L _S2 , the second isolated voltage conversion module 40 , the second switch Q ₂ , and the first single The diode unit 21 and the first inductor L _S1 are formed to form a conduction path.

In FIG. 7D, the first switch Q ₁ and the second switch Q ₂ are not turned on. At this time, the second inductor L _S2 , the first capacitor C _S and the first inductor L _S1 form a conduction path. A conductive path is formed inside the second isolated voltage conversion module 40.

According to the present invention, in the energy storage mode, the single-phase bridgeless isolated power factor adjusting circuit of the present invention can have different working modes according to the waveform of the voltage input by the alternating current power source V _S being a positive half cycle or a negative half cycle. The first single-flow diode unit 21 and the second single-flow diode unit 22 are alternately turned on, and the low-frequency switching diode module 20 is switched between the first conductive state and the second conductive state, and the low frequency Preferably, the switching diode module 20 is switched to the first conducting state and the second conducting state in a low frequency manner.

In addition, in the release mode, the single-phase bridgeless isolation power adjustment circuit of the present invention may have different working modes depending on whether the waveform of the voltage input by the AC power source V _S is a positive half cycle or a negative half cycle.

Note that, in FIG. 7A, the first switch Q ₁ turns on, the isolated T _r1 inductance energy storage coil, the first switching current I _Q1 of linear increase of FIG. 7 during T _on shown in Fig. 7B illustrated by period, the first switch Q ₁ is not turned on (or off), isolated T _r1 of the coil inductance to release stored energy to the load, diode current decreases linearly T 7 I _{Do1 off} of FIG. The low-pass filter formed by Ls ₁ -Cs-Ls ₂ can make the input current of the AC power supply V _S a low-distortion sine wave, thereby achieving the purpose of power correction.

In this embodiment, since the working principle of the negative half cycle is substantially the same as the working principle of the positive half cycle, the working waveform of the negative half cycle can be known from FIG. 8 and will not be described again.

As shown in FIG. 9, below, the single-phase bridgeless isolated power factor adjustment circuit of the present invention is verified via a PSIM analog circuit, wherein the analog input current is 220V _rms , the analog output voltage is 400V _dc , and the simulated rated load is 200W. The simulation results are shown in Figure 10 and Figure 11. Figure 10 shows the switching current I _Q1 , the diode current I _Do1 and the zero current detection signal ZCD waveform during the positive half cycle, which shows that it can indeed achieve zero current detection. The action causes the converter to operate in the boundary conduction mode. Figure 11 shows the waveforms of the various parts of the analog circuit. It shows that the positive and negative half cycles do alternately conduct the two converters. The input voltage and current are in phase, the input current is low distortion, the input power factor is close to one, and the output voltage can be adjusted. A stable 400V, which verifies the effectiveness of the proposed bridgeless isolated converter circuit and its control circuit.

That is, the single-phase bridgeless isolated power factor adjusting circuit of the present invention can be applied to a switching power supply, an AC charger, etc. to improve its efficiency, reduce circuit volume and reduce cost, and can also be used as a single-stage power supply for high-voltage output. Circuits to reduce costs and increase efficiency.

In summary, with the above circuit configuration, the single-phase bridgeless isolated power factor adjustment circuit of the present invention can achieve advantages such as difficulty in failure, simple circuit, cost saving, small size, and high conversion efficiency.

The invention has been described above in terms of the preferred embodiments, and it should be understood by those skilled in the art that the present invention is not intended to limit the scope of the invention. It should be noted that variations and permutations equivalent to those of the embodiments are intended to be included within the scope of the present invention. Therefore, the scope of protection of the present invention is defined by the scope of the patent application.

10‧‧‧EMI filter module

20‧‧‧Low frequency switching diode module

21‧‧‧First single flow diode unit

22‧‧‧Second single flow diode unit

30‧‧‧The first isolated voltage conversion module

40‧‧‧Second isolated voltage conversion module

50‧‧‧First surge absorber module

60‧‧‧second surge absorber module

70‧‧‧First Control Module

71‧‧‧First voltage control unit

72‧‧‧First zero current detection unit

73‧‧‧ first comparison unit

80‧‧‧Second control module

1000‧‧‧Switching power supply

1100‧‧‧PFC rectifier

1200‧‧‧DC to DC converter

2000‧‧‧Switching Power Supply

2100‧‧‧PFC boost AC-DC rectifier

2200‧‧‧Full-bridge phase-shift DC-DC converter

3000‧‧‧Switching power supply

3100‧‧‧Boost AC-DC rectifier

3200‧‧‧LLC Resonant DC-DC Converter

C _o1 ‧‧‧ capacitor

C _o2 ‧‧‧ capacitor

C _S ‧‧‧first capacitor

D ₁ ‧‧‧Single-flow diode

D ₂ ‧‧‧Single-flow diode

D _o1 ‧‧‧ diode

D _o2 ‧‧‧ diode

I _Do1 ‧‧‧ diode current

L _S1 ‧‧‧first inductance

L _S2 ‧‧‧second inductance

Node1‧‧‧ first node

Node2‧‧‧second node

Q ₁ ‧‧‧First switch

Q ₂ ‧‧‧Second switch

T _r1 ‧‧‧Isolated coil

T _r2 ‧‧‧Isolated coil

V _aux ‧‧‧auxiliary coil

V _con ‧‧‧ control signal

V _cs1 ‧‧‧Switch current

V _o ‧‧‧voltage difference

V _o1 ‧‧‧voltage difference

V _o2 ‧‧‧voltage difference

V _{ofb ‧‧‧Output} voltage feedback signal

1 is a circuit diagram of an embodiment of a conventional switched power supply. FIG. 2 is a circuit diagram of another embodiment of a conventional switched power supply. FIG. 3 is a circuit diagram of still another embodiment of a conventional switched power supply. Fig. 4 is a schematic view showing an embodiment of the single-phase isolated power factor adjusting circuit of the present invention. Fig. 5A is a schematic view showing another embodiment of the single-phase isolated power factor adjusting circuit of the present invention. FIG. 5B is a schematic diagram of an embodiment of a control module of the single-phase isolated power factor adjustment circuit of the present invention. FIG. Fig. 6 is an operation waveform diagram of an embodiment of a single-phase bridgeless isolated power factor adjusting circuit of the present invention. 7A is a schematic diagram of the single-phase bridgeless isolated power factor adjustment circuit of the present invention in an energy storage mode during a positive half cycle. 7B is a schematic diagram of the single-phase bridgeless isolated power factor adjustment circuit of the present invention in an energy release mode during a positive half cycle. 7C is a schematic diagram of the single-phase bridgeless isolated power factor adjustment circuit of the present invention in an energy storage mode during a negative half cycle. 7D is a schematic diagram of the single-phase bridgeless isolated power factor adjustment circuit of the present invention in an energy release mode during a negative half cycle. 8 is a working waveform of a control module of the single-phase isolated power factor adjusting circuit of the present invention during a positive half cycle. [Fig. 9] is a simulation diagram of a single-phase bridgeless isolated power factor adjusting circuit of the present invention. 10A to 10C are simulation results of Fig. 9. [Fig. 11A to Fig. 11D] is a simulation result of Fig. 9.

10‧‧‧EMI filter module

20‧‧‧Low frequency switching diode module

30‧‧‧The first isolated voltage conversion module

40‧‧‧Second isolated voltage conversion module

Q ₁ ‧‧‧First switch

Q ₂ ‧‧‧Second switch

R‧‧‧ load

V _S ‧‧‧AC power supply

Claims (9)

A single-phase bridgeless isolated power factor adjustment circuit includes: an EMI filter module coupled to an external AC power source; and a low frequency switching diode module coupled to the EMI filter module; The first switch is coupled to the low frequency switching diode module; a second switch is coupled to the low frequency switching diode module; and a first isolated voltage conversion module coupled to the first switch And a second isolated voltage conversion module coupled to the second switch, wherein when the low frequency switching diode module is in a first conducting state, the first switch is turned on and the first isolated voltage is The conversion module is turned on. When the low frequency switching diode module is in the second conduction state, the second switch is turned on and the second isolated voltage conversion module is turned on, and the low frequency switching diode module includes a first a single-flow diode unit and a second single-flow diode unit are defined as a first conduction state when the second single-flow diode is turned on and the first single-flow diode is turned off. The first single flow is turned on to the diode unit and the second single flow direction When the electrode unit is closed, it is defined as a second conductive state. The single-phase bridgeless isolated power factor adjustment circuit according to claim 1, wherein the first single-flow diode unit and the second single-flow diode unit are alternately turned on, so that the low-frequency switching diode The module is switched between the first conductive state and the second conductive state. The single-phase bridgeless isolated power factor adjustment circuit of claim 1, wherein the EMI filter module comprises: a first inductor, one end of the first inductor is coupled to one end of the AC power source; a second inductor, one end of the second inductor is coupled to the other end of the AC power source; and a first capacitor, the first The two ends of the capacitor are respectively coupled to the other end of the first inductor and the other end of the second inductor. The single-phase bridgeless isolated power factor adjusting circuit of claim 3, wherein the low frequency switching diode module comprises a first single-flow diode unit and a second single-flow diode unit, the first a negative terminal of the single current diode is coupled to one end of the first capacitor and the other end of the first inductor, and the negative terminal of the second single-flow diode unit is coupled to the other end of the first capacitor And the other end of the second inductor. The single-phase bridgeless isolated power factor adjustment circuit of claim 4, wherein the first single-flow diode unit and the second-side diode unit are coupled to the first terminal The node, the one end of the first switch and the one end of the second switch are coupled to a second node, and the first node is coupled to the second node. The single-phase bridgeless isolated power factor adjustment circuit of claim 1, further comprising: a first surge absorbing module coupled to the first switch and the first isolated voltage conversion module; The second surge absorbing module is coupled to the second switch and the second isolated voltage conversion module. The single-phase bridgeless isolated power factor adjustment circuit as claimed in claim 1 further includes: a first control module coupled to the gate terminal of the first switch to control the opening and closing of the first switch; and a second control module coupled to the gate terminal of the second switch to control the The second switch is opened and closed. The single-phase bridgeless isolated power factor adjustment circuit of claim 7, wherein the first control module includes a first voltage control unit, a first zero current detecting unit, and a first comparing unit, The first control module is coupled to the output end of the first isolated voltage conversion module to obtain a first output voltage feedback signal, and the first voltage control unit adjusts the first output voltage feedback signal to output a first a first current detecting unit is coupled to the first isolated voltage converting module to output a first zero current detecting signal, and the first comparing unit compares the first switching current control signal And a voltage of one end of the first switch, and outputting a first control signal according to the comparison result and the first zero current detection signal, wherein the first control signal is used to control the opening and closing of the first switch. The single-phase bridgeless isolated power factor adjustment circuit of claim 8, wherein the second control module includes a second voltage control unit, a second zero current detecting unit, and a second comparing unit, The second control module is coupled to the output end of the second isolated voltage conversion module to obtain a second output voltage feedback signal, and the second voltage control unit adjusts the second output voltage feedback signal to output a first a second switch current control signal coupled to the second isolated voltage conversion module to output a second zero current detection signal, the second comparison unit comparing the second switch current control signal And a voltage at one end of the second switch, and according to the comparison result and the first The first current detecting signal outputs a second control signal, and the second control signal is used to control the opening and closing of the second switch.