CN211046757U

CN211046757U - Bridgeless PFC circuit

Info

Publication number: CN211046757U
Application number: CN201922442239.5U
Authority: CN
Inventors: 李坚
Original assignee: WUHAN RECTIFIER INSTITUTE
Current assignee: WUHAN RECTIFIER INSTITUTE
Priority date: 2019-12-30
Filing date: 2019-12-30
Publication date: 2020-07-17
Anticipated expiration: 2029-12-30

Abstract

The utility model provides a no bridge PFC circuit, including switch tube S1, switch tube S2, inductance L1, inductance L2, electric capacity C1, electric capacity C2, diode D1, diode D2, resistance R1, alternating current power supply is through inductance L1 in proper order, electric capacity C1, inductance L2, diode D1 ' S positive pole, diode D1 ' S negative pole, resistance R1 ground connection, inductance L1, electric capacity C1 ' S common terminal is through switch tube S1 in proper order, switch tube S2 ground connection, switch tube S1, switch tube S2 ' S current flow is opposite, inductance L2, diode D1 ' S common terminal is through diode D2 ' S negative pole, diode D2 ' S positive pole ground connection, electric capacity C2 is parallelly connected with resistance R1 the utility model discloses compare with traditional APFC, the rectifier bridge has been omitted, the circuit ripple is little, the on-state loss is low, the circuit conversion efficiency is high, and the circuit structure is simple, and the cost is reduced.

Description

Bridgeless PFC circuit

Technical Field

The utility model relates to a power electronics technical field especially relates to a no bridge PFC circuit.

Background

Because the traditional active power factor correction circuit (APFC) has a simple structure and mature control method, the APFC is the power factor correction topology which is most used at present. The APFC is composed of a bridge rectifier circuit and a Boost converter, three switching devices are always in working states in the circuit at any moment, the on-state loss of the system is obviously increased along with the improvement of the power level and the switching frequency of the converter, and the overall efficiency is reduced.

SUMMERY OF THE UTILITY MODEL

In view of this, the utility model provides a no bridge PFC circuit to solve the big, the inefficiency problem of traditional APFC on-state loss.

The technical scheme of the utility model is realized like this, the utility model provides a no bridge PFC circuit, including switch tube S1, switch tube S2, inductance L1, inductance L2, electric capacity C1, electric capacity C2, diode D1, diode D2, resistance R1, alternating current power supply is through inductance L1, electric capacity C1, inductance L2, the positive pole of diode D1, diode D1 'S negative pole, resistance R1 ground connection in proper order, inductance L1, electric capacity C1' S common terminal is through switch tube S1, switch tube S2 ground connection in proper order, switch tube S1, switch tube S2 'S current flow is opposite, inductance L2, diode D1' S common terminal is through diode D2 'S negative pole, diode D2' S positive pole ground connection, electric capacity C2 is parallelly connected with resistance R1.

Optionally, the switch tube S1 and the switch tube S2 are MOS tubes, and the common terminal of the inductor L1 and the capacitor C1 is grounded through the drain of the switch tube S1, the source of the switch tube S1, the source of the switch tube S2, and the drain of the switch tube S2 in sequence.

Optionally, the bridgeless PFC circuit further includes a first turn-off absorption circuit and/or a second turn-off absorption circuit, the first turn-off absorption circuit is adapted to be connected in parallel with the switching tube S1, and the second turn-off absorption circuit is adapted to be connected in parallel with the switching tube S2.

Optionally, the first turn-off absorption circuit includes a resistor R2, a capacitor C3, and a diode D3, a drain of the switch tube S1 is connected to a source of the switch tube S1 through a resistor R2 and a capacitor C3 in sequence, the diode D3 is connected in parallel to the resistor R2, and a common terminal of the resistor R2 and the capacitor C3 is connected to a cathode of the diode D3.

Optionally, the second turn-off absorption circuit includes a resistor R3, a capacitor C4, and a diode D4, a drain of the switch tube S2 is sequentially connected to a source of the switch tube S2 through the capacitor C4 and the resistor R3, the diode D4 is connected in parallel to the resistor R3, and a common terminal of the resistor R3 and the capacitor C4 is connected to an anode of the diode D4.

Optionally, the bridgeless PFC circuit further includes an on absorption circuit, and the on absorption circuit is connected between the common terminal of the inductor L1 and the capacitor C1 and the drain of the switching tube S1.

Optionally, the turn-on absorption circuit includes an inductor L3, a resistor R4, and a diode D5, a common terminal of the inductor L1 and the capacitor C1 is connected to a drain of the switching tube S1 via an inductor L3, the resistor R4 and the diode D5 are connected in series and then connected in parallel to the inductor L3, and an anode of the diode D5 is connected to a drain of the switching tube S1.

The utility model discloses a no bridge PFC circuit has following beneficial effect for prior art:

(1) compared with the traditional APFC, the bridgeless PFC circuit of the utility model omits a rectifier bridge, has stable output voltage, consistent input current and voltage phases of the circuit, small ripple, low on-state loss, high circuit conversion efficiency, simple circuit structure and reduced cost;

(2) the utility model discloses a no bridge PFC circuit can absorb the overvoltage that the switch tube turn-offs production and switch on the overcurrent that produces, avoids the excessive pressure to overflow and burns out the switch tube, has improved the security of circuit.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

Fig. 1 is a circuit diagram of a bridgeless PFC circuit according to the present invention;

fig. 2 is another circuit diagram of the bridgeless PFC circuit according to the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely below with reference to 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 a person skilled in the art without creative work all belong to the protection scope of the present invention.

As shown in fig. 1, the bridgeless PFC circuit of the present invention includes a switch tube S1, a switch tube S2, an inductor L1, an inductor L2, a capacitor C1, a capacitor C2, a diode D1, a diode D2, and a resistor R1, wherein an ac power source sequentially passes through the inductor L1, the capacitor C1, the inductor L2, the anode of the diode D1, the cathode of the diode D1, and the resistor R1, a common terminal of the inductor L1 and the capacitor C1 sequentially passes through the switch tube S1 and the switch tube S2, current flows of the switch tube S1 and the switch tube S2 are opposite, a common terminal of the inductor L2 and the diode D1 passes through the cathode of the diode D2 and the anode of the diode D2, and the capacitor C2 is connected in parallel with the resistor R1.

In the embodiment, the switch tube S1 and the switch tube S2 are preferably MOS tubes, and the common ends of the inductor L and the capacitor C1 are grounded through the drain electrode of the switch tube S1, the source electrode of the switch tube S1, the source electrode of the switch tube S2 and the drain electrode of the switch tube S2 in sequence.

In the embodiment, when alternating current output by an alternating current power supply is in a positive half cycle, current flowing through an inductor L is positive, in the first stage, a switching tube S1 is switched on, the current flows through a body diode of a switching tube S2 after flowing through a switching tube S1, the inductor L stores energy, a capacitor C1, an inductor L and a diode D2 form a resonant circuit, energy stored in a capacitor C1 is transferred to an inductor L2, the capacitor C2 provides electric energy for a load resistor R1, in the second stage, the switching tube S1 is switched off, the current flows through the inductor L and then flows through the inductor L and the diode D1 to provide electric energy for the load resistor R1, the energy stored in the inductor L cannot change suddenly, the voltage at two ends of the load resistor R1 is the sum of the voltage at two ends of the power supply voltage and the voltage at two ends of the inductor L1, voltage regulation is realized, at the moment, the capacitor C2 and the capacitor C2 are in a charging state, the energy stored in the inductor L is continuously reduced, when the alternating current output by a half cycle, the same as the alternating current output by a half cycle, when the positive half cycle, the positive current flows to the positive half cycle, the positive half.

Optionally, the bridgeless PFC circuit further includes a first turn-off absorption circuit and/or a second turn-off absorption circuit, the first turn-off absorption circuit is adapted to be connected in parallel with the switching tube S1, and the second turn-off absorption circuit is adapted to be connected in parallel with the switching tube S2. The first turn-off absorption circuit can be used for absorbing overvoltage generated when the switching tube S1 is turned off, and the second turn-off absorption circuit can be used for absorbing overvoltage generated when the switching tube S2 is turned off. Therefore, the bridgeless PFC circuit can absorb the overvoltage generated when the switch tube S1 and/or the switch tube S2 are turned off, the switch tube S1 and/or the switch tube S2 are prevented from being burnt by the overvoltage, and the safety of the circuit is improved.

Specifically, as shown in fig. 1, the first turn-off absorption circuit includes a resistor R2, a capacitor C3, and a diode D3, a drain of the switching tube S1 is connected to a source of the switching tube S1 through a resistor R2 and a capacitor C3 in sequence, the diode D3 is connected to the resistor R2 in parallel, and a common terminal of the resistor R2 and the capacitor C3 is connected to a cathode of the diode D3.

In this embodiment, when the switching tube S1 is turned off, the overvoltage charges the capacitor C3 through the diode D3, the capacitor C3 absorbs the overvoltage generated when the switching tube S1 is turned off, and when the switching tube S1 is turned on, the electric energy stored in the capacitor C3 is discharged through the resistor R2, so that the resistor R2, the capacitor C3, and the diode D3 are charged and discharged along with the switching cycle of the switching tube S1, and the overvoltage generated when the switching tube S1 is turned off can be absorbed, thereby preventing the switching tube S1 from being burnt by the overvoltage.

Optionally, as shown in fig. 1, the second turn-off absorption circuit includes a resistor R3, a capacitor C4, and a diode D4, a drain of the switching tube S2 is connected to a source of the switching tube S2 through the capacitor C4 and the resistor R3 in sequence, the diode D4 is connected to the resistor R3 in parallel, and a common terminal of the resistor R3 and the capacitor C4 is connected to an anode of the diode D4.

In this embodiment, when the switching tube S2 is turned off, the overvoltage charges the capacitor C4 through the diode D4, the capacitor C4 absorbs the overvoltage generated when the switching tube S2 is turned off, and when the switching tube S2 is turned on, the electric energy stored in the capacitor C4 is discharged through the resistor R3, so that the resistor R3, the capacitor C4, and the diode D4 are charged and discharged along with the switching cycle of the switching tube S2, and the overvoltage generated when the switching tube S2 is turned off can be absorbed, thereby preventing the switching tube S2 from being burnt by the overvoltage.

Optionally, the bridgeless PFC circuit further includes an on absorption circuit, and the on absorption circuit is connected between the common end of the inductor L1 and the capacitor C1 and the drain of the switch tube S1, and the on absorption circuit is configured to absorb an overcurrent generated when the switch tube S1 is turned on, so that the switch tube S1 is prevented from being burnt by the overcurrent, and the safety of the circuit is improved.

Specifically, as shown in fig. 2, the turn-on absorption circuit includes an inductor L3, a resistor R4, and a diode D5, a common terminal of the inductor L1 and the capacitor C1 is connected to a drain of the switching tube S1 via an inductor L3, the resistor R4 and the diode D5 are connected in series and then connected in parallel to the inductor L3, and an anode of the diode D5 is connected to a drain of the switching tube S1.

In the embodiment, when the switch tube S1 is turned on, transient current generated by the turn-on of the switch tube S1 flows through the inductor L3, the inductor L3 stores energy, the transient current is suppressed by the inductor L3 because the inductor current cannot suddenly change, and when the switch tube S1 is turned off, electric energy stored in the inductor L3 discharges to the resistor R4 through the diode D5, so that overcurrent generated when the switch tube S1 is turned on can be effectively absorbed, and the switch tube S1 is prevented from being burnt by overcurrent.

The above description is only a preferred embodiment of the present invention, and should not be taken as limiting the invention, and any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A bridgeless PFC circuit is characterized by comprising a switch tube S1, a switch tube S2, an inductor L1, an inductor L2, a capacitor C1, a capacitor C2, a diode D1, a diode D2 and a resistor R1, wherein an alternating current power supply sequentially passes through an inductor L1, a capacitor C1, an inductor L2, the anode of the diode D1, the cathode of a diode D1 and a resistor R1 and is grounded, the common end of the inductor L1 and the common end of the capacitor C1 sequentially passes through a switch tube S1 and a switch tube S2 and is grounded, the current flow directions of the switch tube S1 and the switch tube S2 are opposite, the common end of the inductor L2 and the diode D1 passes through the cathode of a diode D2 and the anode of a diode D2 and the capacitor C2 is connected with the resistor R1 in parallel.

2. The bridgeless PFC circuit of claim 1, wherein the switching tube S1 and the switching tube S2 are both MOS tubes, and a common terminal of the inductor L1 and the capacitor C1 is grounded through a drain of the switching tube S1, a source of the switching tube S1, a source of the switching tube S2 and a drain of the switching tube S2 in sequence.

3. The bridgeless PFC circuit of claim 2, further comprising a first turn-off snubber circuit adapted to be connected in parallel with a switch tube S1 and/or a second turn-off snubber circuit adapted to be connected in parallel with a switch tube S2.

4. The bridgeless PFC circuit of claim 3, wherein the first turn-off absorption circuit comprises a resistor R2, a capacitor C3 and a diode D3, the drain of a switch tube S1 is connected with the source of a switch tube S1 through a resistor R2 and a capacitor C3 in sequence, the diode D3 is connected with the resistor R2 in parallel, and the common end of the resistor R2 and the capacitor C3 is connected with the cathode of a diode D3.

5. The bridgeless PFC circuit of claim 3, wherein the second turn-off absorption circuit comprises a resistor R3, a capacitor C4 and a diode D4, the drain of a switch tube S2 is connected with the source of a switch tube S2 through a capacitor C4 and a resistor R3 in sequence, the diode D4 is connected with a resistor R3 in parallel, and the common end of the resistor R3 and the capacitor C4 is connected with the anode of a diode D4.

6. The bridgeless PFC circuit of claim 2 or 4, further comprising a turn-on snubber circuit coupled between a common terminal of the inductor L1, the capacitor C1, and the drain of the switch tube S1.

7. The bridgeless PFC circuit of claim 6, wherein the turn-on absorption circuit comprises an inductor L3, a resistor R4 and a diode D5, a common terminal of the inductor L1 and a capacitor C1 is connected with a drain of a switch tube S1 through an inductor L3, the resistor R4 and the diode D5 are connected in series and then connected with an inductor L3 in parallel, and an anode of the diode D5 is connected with a drain of the switch tube S1.