WO2013078602A1

WO2013078602A1 - Bridgeless power factor correction converter

Info

Publication number: WO2013078602A1
Application number: PCT/CN2011/083097
Authority: WO
Inventors: 刘立向; 李战伟
Original assignee: 深圳市核达中远通电源技术有限公司
Priority date: 2011-11-29
Filing date: 2011-11-29
Publication date: 2013-06-06
Also published as: CN102742132A

Abstract

A bridgeless power factor correction converter includes an input power supply (AC), a first inductor (L1A), a second inductor (L1B), a first switching transistor (S1), a second switching transistor (S2), a first diode (D1), a second diode (D2), and an output capacitor (Co). The first terminal of the input power supply (AC) is connected with the anode of the first diode (D1) through the first inductor (L1A). The second terminal of the input power supply (AC) is connected with the anode of the second diode (D2) through the second inductor (L1B). The cathode of the first diode (D1) and the cathode of the second diode (D2) are connected with one terminal of the output capacitor (Co). The other terminal of the output capacitor (Co) is connected with the anode of the first diode (D1) and the anode of the second diode (D2) through the first switching transistor (S1) and the second switching transistor (S2). The converter further includes a selective conduction unit (D3). The other terminal of the output capacitor (Co) is connected with the first switching transistor (S1) and the second switching transistor (S2) through the selective conduction unit (D3). The common-mode noise of the power factor correction converter can be reduced effectively by setting the selective conduction unit (D3).

Description

Bridgeless power factor correction converter

The present invention relates to power electronics, and more particularly to a bridgeless power factor correction converter. Background technique

The existing conventional Bridgeless PFC (Power Factor Correction) circuit is shown in Figure 1. Its features are low cost, low efficiency and high efficiency. The missing point is that there is severe EMI common mode noise. An improved bridgeless PFC circuit is shown in Fig. 2, which is characterized by solving the problem of EMI common mode noise, similar to a conventional bridged PFC. The disadvantage is that two book diodes D3, D4 are added, which can only reduce the loss of half of the rectifier bridge. Equivalent to two identical PFC circuits operating separately, with low inductance utilization and low power density. Another improved bridgeless PFC circuit (see U.S. Patent No. 7,215,560 B2) is shown in Figure 3, which is characterized by the replacement of D3/D4 in Figure 2 with a capacitor C1/C2. The disadvantage is that the capacitor will pass a large current and require a large capacitance. In addition, the life of the capacitor is short, which reduces the reliability of the whole machine; two inductors are required, and the power density is low.

Reference patent documents -

ZL 200510079923. 1;

US 7215560 B2;

Summary of the invention

The main object of the present invention is to provide a bridgeless power factor correction converter with low common mode noise and high power density in view of the deficiencies of the prior art.

To achieve the above object, the present invention adopts the following technical solutions:

A bridgeless power factor correction converter includes an input power source, a first inductor, a second inductor, a first switch transistor, a second switch transistor, a first diode, a second diode, and an output capacitor, the input a first end of the power source is connected to the anode of the first diode through the first inductor, and a second end of the input power source is connected to an anode of the second diode through the second inductor, a diode and a cathode of the second diode are connected to one end of the output capacitor, and the other end of the output capacitor is connected to the first two through the first switch tube and the second switch tube respectively The pole tube and the anode of the second diode, the bridgeless power factor correction converter is characterized by further comprising a selective conducting unit, wherein the other end of the output capacitor is connected through a selective conducting unit Connecting the first switch tube and the second switch tube.

The first inductor and the second inductor may be formed by a coupled inductor, or two independent inductors may be used.

According to an embodiment, the selective conducting unit is a third diode or a power switch, and if the third diode is employed, its anode is connected to the other end of the output capacitor.

The power switch tube may be a metal oxide semiconductor field effect transistor (MOSFET) or an insulated gate bipolar transistor (IGBT), or other types of switch tubes may be used.

According to another embodiment, the selective conducting unit includes a third diode and a third switching transistor connected in parallel to the third diode, the anode of the third diode connecting the output The other end of the capacitor.

The selective conducting unit may further include a fourth switching tube, and the fourth switching tube is connected to the third switching tube and connected in parallel to the third diode.

A bridgeless power factor correction converter includes an input power source, a first inductor, a first switching transistor, a second switching transistor, a first diode, a second diode, and an output capacitor, the first of the input power sources Connecting the anode of the first diode through the first inductor, the second end of the input power source is connected to the anode of the second diode, the first diode and the second second a cathode of the pole tube is connected to one end of the output capacitor, and the other end of the output capacitor is connected to the first diode and the second diode through the first switch tube and the second switch tube respectively The anode is characterized in that it further comprises a selective conducting unit, and the other end of the output capacitor is connected to the first switching tube and the second switching tube through a selective conducting unit.

A bridgeless power factor correction converter includes an input power source, a first inductor, a second inductor, a first switch transistor, a second switch transistor, a third switch transistor, a fourth switch transistor, and an output capacitor, wherein the input power source The first end is connected to one end of the first switch tube through the first inductor, and the second end of the input power source is connected to one end of the third switch tube through the second inductor, the first switch tube and The other end of the third switch tube is connected to one end of the output capacitor, and the other end of the output capacitor is connected to the one end of the first switch tube through the second switch tube and the fourth switch tube respectively And the one end of the third switch tube, further comprising a selective turn-on unit, wherein the other end of the output capacitor is connected to the two switch tubes and the fourth through a selective turn-on unit turning tube.

According to an embodiment, the selective conducting unit is a third diode or a power switching tube, and if the third diode is employed, an anode thereof is connected to the other end of the output capacitor. According to another embodiment, the selective turn-on unit includes a third diode and a fifth switch tube connected in parallel to the third diode, and an anode of the third diode connects the output The other end of the capacitor.

A bridgeless power factor correction converter includes an input power source, a first inductor, a first switch transistor, a second switch transistor, a third switch transistor, a fourth switch transistor, and an output capacitor, and the first end of the input power source passes The first inductor is connected to one end of the first switch tube, the second end of the input power source is connected to one end of the third switch tube, and the other end of the first switch tube and the third switch tube are connected One end of the output capacitor, and the other end of the output capacitor is connected to the one end of the first switch tube and the third switch tube through the second switch tube and the fourth switch tube respectively The one end is characterized in that it further comprises a selective conducting unit, and the other end of the output capacitor is connected to the two switching tubes and the fourth switching tube through a selective conducting unit.

A bridgeless power factor correction circuit comprising a plurality of any of the foregoing bridgeless power factor correction converters interleaved in parallel, the bridgeless power factor correction converters sharing the input power supply and the output capacitance.

The beneficial technical effects of the present invention are:

The present invention provides a selective conducting unit, such as a diode or a power switching transistor, on the other end of the output capacitor, the selective conducting unit being configured as a (diode) or controllable (power switching tube) only allowing it to be desired The direction is turned on, so that the parasitic capacitance is not always in a state of charge and discharge during the switching period. Thus, since the charging current on the parasitic capacitance is small and the voltage value is relatively stable, the common mode noise is effectively reduced. Compared with the existing bridgeless power factor correction converter, the invention can reduce the volume of the power supply, increase the power density, reduce the EMI common mode noise, and can achieve better cost, efficiency, power density, volume, and EMI. Balance.

DRAWINGS

1 is a topological diagram of a prior art bridgeless power factor correction converter;

2 is a topological diagram of a conventional second bridgeless power factor correction converter;

3 is a topological diagram of a third bridgeless power factor correction converter;

4 is a top view of a bridgeless power factor correction converter according to an embodiment of the present invention; FIG. 5A shows that the second diode D2 of the positive half cycle of the circuit shown in FIG. 4 is not involved;

Figure 5B shows that the first diode D1 of the negative half cycle of the circuit shown in Figure 4 is not involved;

Figure 6 and Figure 7 show the parasitic capacitance to ground and the equivalent parasitic capacitance between input and output in the circuit shown in Figure 4, respectively;

Figure 8 shows the voltage waveform on the equivalent parasitic capacitance in the circuit shown in Figure 1;

Figure 9 is a diagram showing voltage waveforms on the equivalent parasitic capacitance in the circuit shown in Figure 4; 10-14 illustrate a bridgeless power factor correction converter in accordance with further embodiments of the present invention; FIG. 15 illustrates an interleaved parallel bridgeless power factor correction conversion circuit in accordance with one embodiment of the present invention;

Figure 16 shows the case where the switch S3 of the circuit shown in Figure 11 uses a MOSFET;

17a, b show the reverse recovery characteristics of the diode diodes of the diode D3 and the MOSFET of the circuit shown in Fig. 16;

Figure 18 is a diagram showing a case where the switching transistors S3, S4 of the circuit shown in Figure 12 are connected in series with the top MOSFET;

Figure 19 is a top view of a bridgeless power factor correction converter in accordance with yet another embodiment of the present invention. detailed description

The invention will be further described in detail below by means of embodiments with reference to the accompanying drawings.

Referring to FIG. 4, in one embodiment, the PFC converter includes an input power source A, first and second inductors L1A, LIB, first and second switch transistors S1, S2, and first to third diodes D1, D2. ,

D3, and the output capacitor Co. The specific connection method of the circuit is shown in Figure 4.

The circuit works as follows:

During the positive half cycle, the second switch S2 is always in the open (or high frequency switch) state, the first switch S1 is in the high frequency switch state, and when the first switch S1 is turned on, the power is passed through the first switch S1 and the first switch The second switch S2 charges and stores the first inductor L1A and the second inductor LIB. When the current reaches the set value, the first switch S1 is turned off, and the first inductor L1A and the second inductor LIB are reversed, and the power is passed through the power supply. The first diode D1, the third diode D3 and the second switching transistor S2 charge the output capacitor Co and transfer energy to the load of the subsequent stage. When the inductor current drops to the set value (or the end of the switching period), the first switch S1 is turned on, and the inductors L1A and LIB are recharged and stored, so that they are repeated. At the positive half of the input, the second diode D2 does not participate in the operation, see Figure 5A. The positive half cycle of the input can also be turned on by the body diode of the second switch S2, in which case it is also feasible that the second switch S2 is in the high frequency switching state.

During the input negative half cycle, the first switch S1 is always in the open (or high frequency switch) state, the second switch S2 is in the high frequency switch state, and when the second switch S2 is turned on, the power is passed through the second switch S2 and the A switching transistor S1 charges and stores the second inductor LIB and the first inductor L1A. When the current reaches a set value, the second switching transistor S2 is turned off, and the second inductor LIB and the first inductor L1A are reversed in voltage, and are connected in series with the power source. The second diode D2, the third diode D3 and the first switching transistor S 1 charge the output capacitor Co and transfer energy to the load of the subsequent stage. When the inductor current drops to the set value (or the end of the switching period), the second switch S2 is turned on, and the inductors LIB and L1A are charged again to store energy. So repeating this week. At the input negative half cycle, the first diode D1 does not participate in the operation, see Fig. 5B. The input negative half cycle can also be turned on by the body diode of the first switching transistor SI. In this case, it is also feasible that the first switching transistor S1 is in the high frequency switching state.

Let's analyze the role of the third diode D3, see Figure 6. Assuming that the N line is connected to the ground, the parasitic capacitance of the output to the earth is represented by Cp, and the parasitic capacitance of the output ground to the earth is represented by Cn. The parasitic capacitance equivalent between input and output is expressed as C1, see Figure 7.

Figure 8 shows the voltage waveform on the equivalent capacitor C1 when L1=L2 (or L1A=L1B) without the third diode D3 (see Figure 1). During the positive half cycle of the input, the charge and discharge voltage waveforms of several switching cycles on the equivalent capacitor C1 periodically change between ^^ and

twenty two

Vin, where Vin is the input AC voltage and Vo is the output voltage of the PFC circuit, with reference to the output ground.

Fig. 9 shows a case where the third diode D3 is provided in the embodiment of the present invention (see Fig. 4), and the voltage waveform on the equivalent capacitance C1 is when L1A = L1B or L1 = L2. Due to the presence of the third diode D3, the voltage waveform of charge and discharge in a plurality of switching cycles on the equivalent capacitor C1 is maintained at ^^ during the positive half cycle of the input. When the negative half cycle is input, the charge and discharge amplitude of the equivalent capacitor C1 changes.

2

The situation is the same as the input half a week.

Comparing Fig. 8 and Fig. 9, it can be seen that the equivalent capacitor C1 greatly reduces the voltage fluctuation at both ends during the high frequency switching period, thereby significantly reducing the common mode noise of EMI.

Referring to Fig. 10, according to another embodiment, the third diode D3 of Fig. 4 can be replaced with a power switch tube S3. By controlling the timing at which the power switch S3 is turned on and off, the power switch S3 can function the same as the third diode D3 shown in FIG.

Referring to FIG. 11, according to still another embodiment, the third diode D3 of FIG. 4 may be replaced with another form of selective conduction unit including a third diode D3 and a third diode connected in parallel. The third switching transistor S3 between the cathode and the anode of the D3, the output capacitor Co is connected to the first switching transistor S1 and the second switching transistor S2 through the third diode D3 and the third switching transistor S3. The reason for adding the third switch S3 is as follows: taking the switch S3 as the MOSFET as an example, see FIG. 16, wherein SD3 is the body diode of the switch S3, and the recovery characteristics of the body diode of the MOSFET are not as good as the recovery characteristics of the individual diodes, as shown in the figure. 17a and 17b, so this embodiment can reduce the loss caused by the difference in reverse current recovery characteristics by means of the diode D3 and the switching tube S3 alone, and improve the efficiency. The operation of the circuit shown in Figures 10 and 11 is similar to that of the circuit shown in Figure 4, except that the control of the switch S3 is increased. When the first switch S1 is turned on, the switch S3 is turned off when the first switch S1 is turned on; when the first switch S1 is turned off, the switch S3 is turned on. When the second switch S2 is turned on, the switch S3 is turned off when the second switch S2 is turned on; when the second switch S2 is turned off, the switch S3 is turned on.

Referring to Fig. 12, according to another embodiment, the third switch S3 of Fig. 11 may be further replaced with a third switch S3 and a fourth switch S4 connected in series in a top form. The third switch S3 and the fourth switch S4 in Fig. 12 are the same as those of the third switch S3 in Fig. 11. The advantage of using two switching tubes in series with the top is that the switching tubes S3 and S4 are MOSFETs, see Figure 18. SD3 and SD4 are the body diodes of the switch tubes S3 and S4 respectively, and the on-time of the switch tubes S3 and S4 is t1, so that the diode D3 acts at the time t2, and the direction of the body diodes SD3 and SD4 is opposite in the t2 time. The current has no path, which avoids losses due to poor reverse current recovery characteristics of the MOSFET body diode and improves efficiency. In addition, the presence of the parallel diode D3 provides a reliable one-way conduction branch that prevents the body diodes of the switching transistors S3, S4 from adversely affecting the top connection. In Fig. 18, the sources of the switching transistors S3, S4 are connected together. Alternatively, it is also possible that the drains of the switching transistors S3, S4 are connected together to form a top.

Referring to FIG. 13, according to still another embodiment, the first and second diodes D1, D2 in FIG. 4 may also be replaced with power switch tubes S1, S3, and the connection of the output capacitor Co to the output end is selected. The sexual conduction unit may also be a power switch tube S5 or a diode (not shown).

In some embodiments, the first inductance and the second inductance can be two separate inductances. Figure 14 shows an embodiment using two independent inductors, L1 and L2, each of which is equivalent to half the size of one inductor in the circuit shown in Figure 2.

In a preferred embodiment, as shown in FIG. 4 and FIG. 10-13, the first inductor L1A and the second inductor LIB are in the form of a coupled inductor, and the total volume of the coupled inductor is equivalent to the size of one inductor in the circuit shown in FIG. . With coupled inductors, the number of inductors can be reduced, the volume can be reduced, the power density of the power supply can be increased, and the utilization of the inductor can be improved.

15 is an interleaved, bridgeless power factor correction circuit of an embodiment having a n-bridged power factor correction converter main circuit in an interleaved parallel manner, in addition to a common input power supply and output capacitance, n is greater than or equal to 2, each The structure of a main circuit is similar to that of the circuit shown in Fig. 4, and diodes D3, D23 ... Dn3 are added, and a main circuit similar to the other embodiments can also be employed.

Figure 19 illustrates a bridgeless power factor correction converter of yet another embodiment, with Figure 4 and Figure The circuit shown in Figure 14 differs in that only one inductor L1 is used. This is the limit of the inductance of inductor L1A and inductor LIB (Fig. 4) or inductor L1 and inductor L2 (Fig. 14), that is, the inductance of inductor LIB. The amount is 0, and the inductance of the inductor L1A is the sum of the inductances of the previous inductor L1A and LIB (or the inductance of the inductor L2 is 0, and the inductance of the inductor L1 is the sum of the inductances of the previous inductors L1 and L2). vice versa. In this case, the voltage stress of the diode D3 becomes high, which is disadvantageous for the selection of the diode, so that a combination of two inductors or one coupling inductor is used and L1A=L1B or L1=L2 is preferable. In addition to the inductance, other variations of the circuit shown in Figure 19 can be seen in Figures 10-14.

Similarly, the main circuit of each converter in the bridgeless power factor correction circuit shown in Fig. 15 can also use only one inductor.

In all embodiments, each of the switch tubes may be a power switch tube such as a MOSFET or an IGBT, or other types of switch tubes may be used.

The above is a detailed description of the present invention in connection with the specific preferred embodiments, and the specific embodiments of the present invention are not limited to the description. It is to be understood by those skilled in the art that the present invention can be delineated or substituted without departing from the spirit and scope of the invention.

Claims

Claim

A bridgeless power factor correction converter comprising an input power source, a first inductor, a second inductor, a first switch transistor, a second switch transistor, a first diode, a second diode, and an output capacitor The first end of the input power source is connected to the anode of the first diode through the first inductor, and the second end of the input power source is connected to the anode of the second diode through the second inductor. The first diode and the cathode of the second diode are connected to one end of the output capacitor, and the other end of the output capacitor is connected to the first switch tube and the second switch tube respectively a diode and an anode of the second diode, further comprising a selective conducting unit, wherein the other end of the output capacitor is connected to the first switching tube through a selective conducting unit and The second switch tube.

2. The bridgeless power factor correction converter of claim 1, wherein the first inductance and the second inductance are coupled inductors or two independent inductors.

The bridgeless power factor correction converter according to claim 1 or 2, wherein the selective conducting unit is a third diode or a power switching tube, and an anode of the third diode Connecting the other end of the output capacitor.

The bridgeless power factor correction converter according to claim 1 or 2, wherein the selective conducting unit comprises a third diode and a third parallel connected to the third diode a switching transistor, an anode of the third diode is connected to the other end of the output capacitor.

The bridgeless power factor correction converter according to claim 4, wherein the selective conducting unit further comprises a fourth switching tube, and the fourth switching tube is opposite to the third switching tube Connected in parallel to the third diode.

6. A bridgeless power factor correction converter comprising an input power source, a first inductor, a first switch transistor, a second switch transistor, a first diode, a second diode, and an output capacitor, the input power source The first end is connected to the anode of the first diode through the first inductor, the second end of the input power source is connected to the anode of the second diode, the first diode and the first a cathode of the diode is connected to one end of the output capacitor, and the other end of the output capacitor is connected to the first diode and the second diode through the first switch tube and the second switch tube respectively The anode of the pole tube is characterized in that it further comprises a selective conducting unit, and the other end of the output capacitor is connected to the first switching tube and the second switching tube through a selective conducting unit.

7. A bridgeless power factor correction converter comprising an input power source, a first inductor, a second inductor, a first switch transistor, a second switch transistor, a third switch transistor, a fourth switch transistor, and an output capacitor, The first end of the input power source is connected to one end of the first switch tube through the first inductor, and the second end of the input power source is connected to one end of the third switch tube through the second inductor, The other end of the first switch tube and the third switch tube are connected to one end of the output capacitor, and the other end of the output capacitor is connected to the first switch through the second switch tube and the fourth switch tube respectively The one end of the tube and the one end of the third switch tube are characterized by further comprising a selective conducting unit, wherein the other end of the output capacitor is connected to the two switch tubes through a selective conducting unit And the fourth switch tube.

8. The bridgeless power factor correction converter according to claim 7, wherein the selective conduction unit is a third diode or a power switch tube, and the anode connection of the third diode Said other end of the output capacitor.

A bridgeless power factor correction converter comprising an input power source, a first inductor, a first switch transistor, a second switch transistor, a third switch transistor, a fourth switch transistor, and an output capacitor, the first input power source Connecting the first switch to one end of the first switch tube, the second end of the input power source is connected to one end of the third switch tube, and the first switch tube and the third switch tube are One end of the output switch is connected to one end of the output switch, and the other end of the output switch is connected to the one end of the first switch tube and the third switch tube through the second switch tube and the fourth switch tube respectively The one end is further characterized by a selective conducting unit, and the other end of the output capacitor is connected to the two switching tubes and the fourth switching tube through a selective conducting unit.

10. A bridgeless power factor correction circuit comprising a plurality of bridgeless power factor correction converters according to any of claims 1-9, interleaved in parallel, said plurality of bridgeless power factor correction converters The input power source and the output capacitor.