CN1383256A - Method and circuit for correcting power factor - Google Patents
Method and circuit for correcting power factor Download PDFInfo
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- CN1383256A CN1383256A CN02115134A CN02115134A CN1383256A CN 1383256 A CN1383256 A CN 1383256A CN 02115134 A CN02115134 A CN 02115134A CN 02115134 A CN02115134 A CN 02115134A CN 1383256 A CN1383256 A CN 1383256A
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- storage capacitor
- reverse recovery
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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Abstract
This invention discloses a power factor rectify method and its circuit characterized in reducing the loss of reverse recovery current by the following way: after finishing the reverse recovery, at the time when the reverse recovery energy stored in an auxiliary inductance is transferred to the first energy storage capacitance, the first and second energy storage capacitances also input a portion of energy in proportion to Vin from the input voltage. The said energy volume should make the continuous current completely transfer to the first branch when the current is at the sine wave peak value to ensure the action of the current buffer to reduce loss to the utmost. When commercial power voltage crosses zero about, Vin reaches zero, the energy storage capacitance stores only the reverse recovery energy.
Description
Technical field:
The present invention relates to a kind of power factor correction (PFC) method and circuit, be used for the switch power supply equipment of civil power inputs such as communication power supply, uninterrupted power supply (ups) Unity, reduce Harmonics of Input and improve power factor.
Background technology:
Circuit of power factor correction (PFC) is widely used in the switch power supply equipment of civil power inputs such as communication power supply, UPS, to realize making input current satisfy the relevant harmonic standard requirement of IEC, makes power factor be approximately 1 simultaneously.
As shown in Figure 1, traditional work principle of Power Factor Correction Circuit is as follows:
Input voltage (V
IN) be the voltage of civil power sine voltage behind over commutation; Its waveform is the absolute value waveform of sine voltage;
1. by the opening and turn-offing of power controlling switch S 1, make input current follow the tracks of input voltage, it is sinusoidal wave making input current, simultaneously and the input voltage same-phase, makes input current satisfy the relevant harmonic standard requirement of IEC, makes power factor be approximately 1 simultaneously.
2. when the S1 conducting, input voltage is added in inductance L m two ends, and to Lm charging energy storage, the Lm electric current rises, and this moment, sustained diode was oppositely ended;
3. when S1 turn-offs because the Lm inductive current can not suddenly change, the sustained diode conducting, line voltage connect with inductance L m, electric current through sustained diode 1 to output capacitance and electric, the decline of inductance L m electric current.
Above-mentioned traditional circuit of power factor correction exists following problem:
When S1 turn-offed, the forward conduction electric current was flow through in the sustained diode conducting.When the S1 conducting, D bears reverse voltage, because diode exists reverse recovery Effects, D can't end at once, flows through D and have current reversal, forms reverse recovery current.Reverse recovery current flows through power switch S1 with Lm, thereby has increased the loss of turn-on consumption and the D of S1.When output voltage is high more,, make the problems referred to above more serious because the reverse recovery time of high-voltage diode is longer.The switching frequency of S1 is high more, and then the loss that causes of reverse recovery current is big more; The distinctive problem of foregoing circuit has limited the raising of circuit work frequency.
In order to address the above problem, generally the method for Cai Yonging is to adopt an auxiliary induction Ls to connect with sustained diode to reduce reverse recovery current.
Auxiliary induction Ls can only be used for reducing reverse recovery current, can not reduce the loss that reverse recovery current brings.Reduce this loss, also need to increase a storage capacitor Cb and store reverse recovery energy, behind S1 conducting again, again energy stored is sent back to output capacitance.
But the electric current that is introduced as on the inductance L m circuit of storage capacitor provides second branch road, when the Lm electric current is big, because the stored reverse recovery energy of storage capacitor Cb is a little numerical value, it is not enough to guarantee at the S1 blocking interval electric current of second branch road is all transferred on the branch road at sustained diode place.Like this, auxiliary induction Ls can not play a role fully.
For this reason, can design more complicated circuit theoretically, to increase energy storage, so that the electric current of S1 blocking interval second branch road is all transferred on the branch road at sustained diode place.But, increase the energy storage meeting and bring following negative effect: when line voltage during near zero-crossing point, circuit working is in DCM (discontinuous current control) mode, when this working method, exist in some switch periods, in the time of turn-offing at S1, the energy that capacitor C b goes up storage can not all be transferred to output capacitance, thereby form accumulation, cause capacitor C b to go up the voltage pump liter, the energy of voltage buffer is big more, and it is big more that capacitor C b goes up voltage pump increasing degree degree, thereby on fly-wheel diode, cause bigger due to voltage spikes stress, increased requirement of withstand voltage, selected the more diode of high voltage amount for use, thereby increased diode losses fly-wheel diode.
Summary of the invention:
Purpose of the present invention is exactly in order to overcome the above problems, a kind of power factor correcting method and circuit are provided, reduce the loss that reverse recovery current causes, and can not influence auxiliary induction plays a role, can not cause voltage pump liter on the storage capacitor yet, thereby reduce the due to voltage spikes stress on fly-wheel diode.
For achieving the above object, the present invention proposes a kind of power factor correcting method and circuit.
Described power factor correcting method being opened and turn-offing by power controlling switch (S1), make input current follow the tracks of the waveform and the phase place of input civil power sine voltage, thereby raising power factor, it is characterized in that reducing the reverse recovery current loss: 1) after power switch (S1) conducting by following steps, storage capacitor stores when oppositely recovering energy, and storage capacitor also obtains portion from input voltage (VIN) and is proportional to Vin
2Energy, wherein Vin is the instant value of input voltage (VIN); 2) close in the afterflow process of having no progeny at power switch (S1), the reverse recovery that stores can and be proportional to Vin
2Energy transfer to output capacitance (Co).
Described circuit of power factor correction comprises: power switch (S1), output capacitance (Co); It is characterized in that, also comprise: storage capacitor (Cb, Cs) is used to receive reverse recovery energy and portion and is proportional to Vin
2Energy, and close to have no progeny at power switch (S1) this reverse recovery can be delivered to output capacitance (Co), wherein Vin is the instant value of input voltage (VIN).
Since adopted above scheme, when electric current is in sinusoidal wave peak value, because input voltage also is in crest location, thereby CsVin
2Value can be enough big, in the afterflow process that power switch S1 is closed have no progeny, freewheel current can all be transferred on the first afterflow branch road.And at line voltage during near zero-crossing point, because CsVin
2Approach zero, only stored reverse recovery energy on the storage capacitor, this just can not cause storage capacitor Cb to go up the voltage pump liter, thereby can not cause due to voltage spikes stress on fly-wheel diode.
Description of drawings:
Fig. 1 is traditional circuit of power factor correction schematic diagram.
Fig. 2 (A) is the embodiment of the invention one circuit diagram.
Fig. 2 (B) is the embodiment of the invention two circuit diagrams.
Fig. 3 is the working waveform figure of circuit shown in Fig. 2 (A).
Embodiment:
Also the present invention is described in further detail in conjunction with the accompanying drawings below by specific embodiment.
Basic principle of the present invention is to connect with sustained diode at auxiliary induction of employing to reduce on the basis of reverse recovery current method, provide the current transfer energy by increasing a special accumulator, reduce reverse recovery loss, and can realize effectively that the branch road that makes freewheel current all transfer to the sustained diode place gets on, simultaneously, the storage power of each switch periods of accumulator changes with this cycle internal inductance current value size, the inductive current value is big more, and storage power is big more.Otherwise the same, so can not cause relevant capacitor voltage pump liter.
Shown in Fig. 2 (A) and Fig. 2 (B) two kinds of embodiment of the present invention.Should benly be that the last stored energy of the second storage capacitor Cs is not from output capacitance Co is last but from the input voltage vin acquisition, its energy value is
Rather than
, obviously it is to be proportional to Vin
2, so also be proportional to input current square, therefore the energy storage that increases is not a definite value, but changes with input voltage, these characteristics make the present invention avoid the pump liter of storage capacitor voltage just.Fig. 2 (A) is more a kind of in the invention scheme, will be that example is introduced operation principle of the present invention with this scheme below, and the principle of Fig. 2 (B) also similarly.
In order to simplify circuit analysis, in a switch periods, can make the following assumptions:
1. output capacitance is enough big, can think that output voltage V 0 is invariable direct voltage;
2. except sustained diode, all power devices all are desirable devices;
3. inductance L m is much larger than Ls;
4. in switch periods, input voltage vin is constant (because the period of change of input voltage is the civil power cycle, and the switch periods of power switch S is far smaller than the civil power cycle, and therefore in a switch periods, input voltage vin is constant substantially);
Based on above-mentioned assumed condition, we can be divided into 8 time periods to a circuit working cycle and analyze respectively, as shown in Figure 3:
Phase I (t0--t1):
Switch S 1 is in t0 conducting constantly, and sustained diode has reverse recovery current to flow through, and auxiliary induction Ls connects with sustained diode and reduces reverse recovery current.
Second stage (t1--t2)
Sustained diode is ended constantly at t1, and reverse recovery phenomena finishes.This moment, the storage power of Ls was
(I
RrBe the reverse recovery current maximum); D4 nature conducting this moment, electric current flows along Vin--D4--Cs--Cb--Ls--S1--Vin, forms the resonance path.
Phase III (t2--t3)
Work as VCs=V
In, the time (t2 constantly), the conducting of D1 nature, the Cs voltage clamp is at Vin voltage, storage power is
, electric current flows along Ls--S1--D1--Cb--Ls, forms the resonance path, and at t3 constantly, the Ls electric current drops to 0, and this moment, the storage power of Ls was all transferred on the Cb, and this moment, the Cb energy stored was
Voltage on the sustained diode is V0+V at this moment
Cb
Quadravalence section (t3--t4)
At t3 constantly, D1 ends, and Cb and Cs voltage remain unchanged, and enter the S1 conducting operating state of normal pfc circuit.
Five-stage (t4--t5)
At t4 constantly, switch S 1 is turn-offed, because the Lm electric current I
FCan not suddenly change D3 conducting, electric current I
FFlow to output capacitance C0 along D3, simultaneously, the conducting of D5 nature, electric current flows along Ls--Cb--Cs--D5, forms the resonance path, and the Ls electric current is constantly increased, and Cb and Cs voltage constantly reduce, and the electric current on the D3 branch road is transferred on the sustained diode branch road gradually.
The 6th stage (t5--t6)
At t5 constantly, Cs voltage drops to 0, the conducting of D2 nature, and electric current flows along Ls--Cb--D2, forms the resonance path, and the Ls electric current is constantly increased, and Cb voltage constantly reduces, and makes the electric current on the D3 branch road continue to transfer on the sustained diode branch road.
The 7th stage (t6--t7)
At t6 constantly, the Ls electric current is increased to the Lm electric current I
F, electric current is all transferred on the sustained diode branch road, and D3 ends naturally, electric current I
FFlow along the Ls--Cb--D2 constant current, Cb voltage continues to reduce.
The 8th stage (t7--t8)
At t7 constantly, Cb voltage drops to 0, the conducting of sustained diode nature, and D2 ends naturally, and the S1 that enters normal pfc circuit to t8 constantly closes the intermittent current operating state.This moment, Cb and Cs voltage were 0 to remain unchanged.
Can know that from above-mentioned circuit theory analysis total current transfer energy is Cb and Cs storage power sum, can be represented by the formula:
From following formula as can be known, the transfer energy of storage changes along with the variation of Vin, and Vin is big more, and the transfer energy of storage is big more, otherwise Vin is more little, and the transfer energy of storage is more little.
In pfc circuit, input current is sinusoidal wave, and simultaneously with civil power sine voltage same-phase, in the cycle, Lm electric current I F is along with the instantaneous value of input voltage changes and changes at civil power, and Vin is big more, and electric current I F is big more, needs the electric current of transfer big more.Vin is more little, and electric current I F is more little, needs the electric current of transfer more little.
From last surface analysis as can be known, the transfer energy of Cb and Cs storage is along with electric current I
FVariation and change.Work as V
InIn the time of near peak value, the transfer energy of storage is very big, can make electric current I
FThe branch road of effectively transferring to the D place gets on.Work as V
InWhen near zero-crossing point, the transfer energy of storage is very little, thereby has avoided causing capacitor C b to go up the voltage pump liter, can not cause bigger due to voltage spikes stress on fly-wheel diode.
Adopt circuit of the present invention, can adopt bigger auxiliary induction Ls, thereby further reduce reverse recovery current, improve the efficient of entire circuit.
Conclusion: a kind of low-loss circuit of power factor correction of this patent invention, adopt an auxiliary induction to connect and reduce the reverse recovery current method with sustained diode, improved the efficient of circuit, provide the current transfer energy by increasing a special accumulator simultaneously, reducing under the situation of loss, can realize effectively that the branch road that makes freewheel current all transfer to the D place gets on, simultaneously, the storage power of each switch periods of accumulator changes with this cycle internal inductance current value size, the inductive current value is big more, and storage power is big more.Otherwise the same, so can not cause relevant capacitor voltage pump liter, reduced the peak voltage stress of fly-wheel diode, effectively overcome problems of the prior art.Simultaneously, adopt method of the present invention, can use bigger auxiliary induction Ls, thereby further reduce reverse recovery current, improve the efficient of entire circuit.
Claims (6)
1, a kind of power factor correcting method, opening and turn-offing by power controlling switch (S1), make input current follow the tracks of the waveform and the phase place of input civil power sine voltage, thereby improve power factor, it is characterized in that reducing the reverse recovery current loss by following steps:
1) after power switch (S1) conducting, storage capacitor stores when oppositely recovering energy, and storage capacitor is also from input voltage (V
IN) obtain portion and be proportional to Vin
2Energy, wherein Vin is input voltage (V
IN) instant value;
2) close in the afterflow process of having no progeny at power switch (S1), the reverse recovery that stores can and be proportional to Vin
2Energy transfer to output capacitance (Co).
2, power factor correcting method as claimed in claim 1 is characterized in that:
In above-mentioned steps 1) before, in the reversely restoring process of the diode (D) after power switch (S1) conducting, reduce the reverse recovery current of diode (D), will oppositely recover energy simultaneously and be stored in the auxiliary induction (Ls) by auxiliary induction (Ls); After reversely restoring process finished, oppositely recovery can be shifted above-mentioned steps 1 to storage capacitor) beginning;
In above-mentioned steps 2) before or simultaneously, to close in the afterflow process of having no progeny at power switch (S1), freewheel current shifts on the first afterflow branch road that contains fly-wheel diode (D);
The described Vin that is proportional to
2The size of energy guarantee that when input current was in peak value, in above-mentioned afterflow process, freewheel current can all be transferred on first branch road.
3, a kind of power factor correcting method as claimed in claim 1, it is characterized in that: in the thermal energy storage process of storage capacitor (Cb, Cs), by with the voltage clamp at second storage capacitor (Cs) two ends on input voltage (Vin), make the energy of going up storage at second storage capacitor (Cs) remain on (Cs Vin
2The size of the energy that)/2, the first storage capacitors (Cb) are upward stored then equals oppositely to recover energy and adds (Cs Vin
2)/2.
4, a kind of circuit of power factor correction comprises:
Power switch (S1);
Output capacitance (Co);
It is characterized in that, also comprise:
Storage capacitor (Cb, Cs) is used to receive reverse recovery energy and portion and is proportional to Vin
2Energy, and close to have no progeny at power switch (S1) this reverse recovery can be delivered to output capacitance (Co), wherein Vin is input voltage (V
IN) instant value.
5, circuit of power factor correction as claimed in claim 4 is characterized in that:
Also comprise the first afterflow branch road that has auxiliary induction (Ls) and fly-wheel diode (D), described auxiliary induction (Ls) is used to reduce reverse recovery current and the reverse energy that recovers of storage of diode D when power switch (S1) conducting, be used for the reverse recovery that stores can be shifted to storage capacitor when reverse recovery phenomena finishes;
Also comprise with the above-mentioned first afterflow branch road alternately or the second afterflow branch road of concurrent working;
Described storage capacitor comprises first and second storage capacitor (Cb, Cs), and two storage capacitors (Cb and Cs) equal oppositely to recover energy in power switch (S1) the energy sum that conduction period received and add that is proportional to a Vin
2The energy sum, this value guarantees that when input current is in peak value in the afterflow process of having no progeny in power switch (S1) pass, freewheeling circuit is all transferred on the first afterflow branch road from the second afterflow branch road.
6, a kind of circuit of power factor correction as claimed in claim 4 is characterized in that:
First storage capacitor (Cb) end links to each other with auxiliary induction (Ls), and the other end links to each other with output capacitance (Co) by the 3rd fly-wheel diode (D2);
One end of second storage capacitor (Cs) also links to each other with first storage capacitor (Cb), and the other end links to each other with output capacitance (Co) by the 4th fly-wheel diode (D5); And second storage capacitor (Cs) two ends link to each other with an end of input voltage (Vin) by a backward diode (D4, D1) respectively, the direction of backward diode (D4, D1) guarantees in the thermal energy storage process of two storage capacitors (Cb and Cs) with the polarity that is connected to input voltage (Vin), from the energy of input voltage (Vin) with from the energy addition of auxiliary induction (Ls), and after the thermal energy storage process of second storage capacitor (Cs) finishes with its both end voltage clamper on a magnitude of voltage that is proportional to input voltage (Vin).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB021151342A CN1170355C (en) | 2002-04-19 | 2002-04-19 | Method and circuit for correcting power factor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB021151342A CN1170355C (en) | 2002-04-19 | 2002-04-19 | Method and circuit for correcting power factor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1383256A true CN1383256A (en) | 2002-12-04 |
| CN1170355C CN1170355C (en) | 2004-10-06 |
Family
ID=4743469
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB021151342A Expired - Lifetime CN1170355C (en) | 2002-04-19 | 2002-04-19 | Method and circuit for correcting power factor |
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| CN (1) | CN1170355C (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2010124637A1 (en) * | 2009-04-28 | 2010-11-04 | 珠海格力电器股份有限公司 | Single-phase bridgeless power factor correction circuit |
| CN101436829B (en) * | 2003-04-22 | 2011-08-10 | 三垦电气株式会社 | Power factor improving circuit |
| CN105703617A (en) * | 2010-08-18 | 2016-06-22 | 芬斯克斯有限公司 | Multi-path power factor correction method and power converter |
-
2002
- 2002-04-19 CN CNB021151342A patent/CN1170355C/en not_active Expired - Lifetime
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101436829B (en) * | 2003-04-22 | 2011-08-10 | 三垦电气株式会社 | Power factor improving circuit |
| CN101436828B (en) * | 2003-04-22 | 2012-05-09 | 三垦电气株式会社 | Power factor improving circuit |
| WO2010124637A1 (en) * | 2009-04-28 | 2010-11-04 | 珠海格力电器股份有限公司 | Single-phase bridgeless power factor correction circuit |
| CN105703617A (en) * | 2010-08-18 | 2016-06-22 | 芬斯克斯有限公司 | Multi-path power factor correction method and power converter |
| US11038428B2 (en) | 2010-08-18 | 2021-06-15 | Finsix Corporation | Multi-path power factor correction |
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| Publication number | Publication date |
|---|---|
| CN1170355C (en) | 2004-10-06 |
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Address after: 518057 Nanshan District science and Technology Industrial Park, Guangdong, Shenzhen Branch Road, No. Patentee after: Vitamin Technology Co., Ltd. Address before: 518057 Nanshan District science and Technology Industrial Park, Guangdong, Shenzhen Branch Road, No. Patentee before: Aimosheng Network Energy Source Co., Ltd. |
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Granted publication date: 20041006 |