CN103166446B - Power factor correcting device and correcting method thereof - Google Patents

Abstract

The invention discloses a power factor correcting device and a correcting method of a power factor. The power factor correcting device and the correcting method of the power factor keep that an input current is in a simple sinusoidal alternating current form and keeps the input current shares the same phase with an input alternating voltage. An alternating voltage is converted into a full-wave rectification form through a full-bridge rectifier, and is converted into a direct current output voltage through an inducer, a power transistor and a power diode. A current compensating circuit and a voltage compensating circuit respectively generate a compensating current signal and a compensating voltage signal after respectively comparing a correcting current and an output voltage respectively with a reference signal and a reference voltage, and an updated pulse width modulation signal is generated according to the compensating current signal and the compensating voltage signal. The reference current signal is obtained through multiplying the compensating current signal by the compensating voltage signal through a multiplication gainer, so that the input current can be corrected without the needs of sampling an input voltage according to the technology, and response speed of an internal circuit is improved.

Description

Power factor correcting device and bearing calibration thereof

Technical field

The present invention about a kind of alignment technique, particularly about a kind of power factor correcting device and bearing calibration thereof.

Background technology

Now the dealer of power supply unit pursue high-quality power supply and demand be always world community want the target reached, but build power plant's unique channel of not dealing with problems in large quantities, improve the energy of electric power supply on the one hand, improve power factor (PF) (power factor) or the efficiency of electric equipment products on the other hand, could effectively deal with problems.And the Main Function of power factor corrector (power factor corrector) makes the input voltage of electric equipment products identical with the phase place of input current, even if the load of meaning electric equipment products is similar to resistive load, and the harmonic distortion (current harmonic distortion) effectively reducing input current is to reach the high power factor of power supply.

General power factor (PF) correcting device produces a pulse width modulation signal except needs one pulse width modulation signal generator, and needs the reference signal of sampling as correcting current of an input voltage.But, in the prior art, pulse width modulation signal generator disclosed by US Patent No. 5886586, do not need to sample input voltage, and adopt an integrator to carry out a cycle control methods (one cycle controlmethod), to determine the current potential of integrating capacitor discharge and recharge time and integrating capacitor.Other also have the technology of similar integrator as US Patent No. 7068016B2, US5804950.Because above-mentioned patent is in inside circuit or being placed in outside has and use integrator or integrating capacitor, response speed when internal circuit so can be caused to operate declines to a great extent, in addition inside circuit needs a switch to make the electric discharge purposes of integrating capacitor, and way increases power consumption and increases circuit space.

Therefore, the present invention is directed to above-mentioned puzzlement, propose a kind of power factor correcting device and bearing calibration thereof, to solve the problem that prior art produces.

Summary of the invention

Main purpose of the present invention, be to provide a kind of power factor correcting device and bearing calibration thereof, a multiplier is utilized to connect current compensation circuit and voltage compensating circuit, be multiplied with offset current signal with the bucking voltage signal that two compensators are exported, and then obtain the technology of the reference current signal being supplied to current compensation circuit, carry out Active PFC, this technology can avoid the technology utilizing integrating capacitor simultaneously, and the response speed of internal circuit when operating significantly is promoted, to promote power factor (PF) correction usefulness.

For reaching above-mentioned purpose, the invention provides a kind of power factor correcting device, comprise a power stage circuit, connect a load, and receive an alternating voltage, the power transistor driven by inductor, power diode and a pulse wave width modulation signal, to change alternating voltage into an input current according to pulse wave width modulation signal, and exported to load, make load to produce an output voltage.Power stage circuit samples input current by sample resistance, to export as a correcting current.Power stage circuit connects a current compensation circuit, and it receives the error between correcting current and a reference current signal, via current error amplifier and current compensator to produce an offset current signal.Power stage circuit also connects a voltage compensating circuit, is to receive error between output voltage and a reference voltage by voltage divider, then by voltage error amplifier and voltage compensator to produce a bucking voltage signal.The output of current compensation circuit is connected a multiplicative gain device with the output of voltage compensating circuit, receives offset current signal and bucking voltage signal, after being multiplied, then is multiplied by a current gain, produces reference current signal.Current compensation circuit is connected a pulse wave width modulation transducer with described voltage compensating circuit, receives offset current signal and bucking voltage signal, to produce pulse wave width modulation signal, makes alternating voltage identical with the phase place of input current.

Described power stage circuit more comprises a sample resistance, connects described current compensation circuit; And an AC/DC changeover switch, connect described load, described sample resistance, described current compensation circuit and described voltage compensating circuit, and receive described alternating voltage and described pulse wave width modulation signal, to change described alternating voltage into described input current according to described pulse wave width modulation signal, and exported to described load, to produce described output voltage, described sample resistance is utilized again to sample described input current, to export described correcting current.

Described current compensation circuit more comprises a current error amplifier, connects described power stage circuit, and receives described correcting current and a reference current signal, after both this relatively, exports one and compares electric current; And a current compensator, connect described current error amplifier, and receive and describedly compare electric current, after carrying out current compensation, produce described offset current signal.

Described voltage compensating circuit more comprises a voltage divider, connects described power stage circuit, and receives described output voltage, produces a feedback voltage with dividing potential drop; One voltage error amplifier, connects described voltage divider, and receives described feedback voltage and described reference voltage, after both this relatively, exports a comparative voltage; And a voltage compensator, connect described voltage error amplifier, and receive described comparative voltage, after carrying out voltage compensation, produce described bucking voltage signal.

Described multiplicative gain device more comprises a multiplier, connects described current compensation circuit and described voltage compensating circuit, and receives described offset current signal and described bucking voltage signal, after being multiplied, produces a Compensation Feedback electric current; And a current gain adjuster, connect described multiplier, and receive described Compensation Feedback electric current, after being multiplied by described current gain, produce described reference current signal.

Described pulse wave width modulation transducer more comprises a ramp generator, connects described voltage compensating circuit, and receives described bucking voltage signal, to produce an oblique wave signal accordingly; And one changes comparator, connects described ramp generator and described current compensation circuit, and receives described oblique wave signal and described offset current signal, after comparing, export in described pulse wave width modulation signal to described power stage circuit.When the magnitude of voltage of described oblique wave signal is greater than magnitude of voltage corresponding to described offset current signal, described pulse wave width modulation signal is high levle voltage; And the magnitude of voltage of described oblique wave signal is when being less than magnitude of voltage corresponding to described offset current signal, described pulse wave width modulation signal is low level voltage.

Described sample resistance, described pulse wave width modulation signal, described input current, described alternating voltage, described output voltage and described oblique wave signal meet following condition:

R _S·i _in(θ)＝d _OFF(θ)·T _S.W.·S _V；

D _oFF(θ)=V _{in_pk}sin (θ)/V _o=1-d (θ); And

I _in(θ)=V _{in_pk}sin (θ)/R _{in (ac)}, wherein R _sfor the resistance of described sample resistance, i _in(θ) be described input current, V _{in_pk}sin (θ) is described alternating voltage, V _ofor described output voltage, S _vfor the slope of described oblique wave signal, R _{in (ac)}for equivalent inpnt AC resistance, T _s.W.with cycle and duty ratio that d (θ) is described pulse wave width modulation signal respectively.

The present invention also provides a kind of power factor calibrating method, receives an alternating voltage and a pulse wave width modulation signal, to change described alternating voltage into an input current according to described pulse wave width modulation signal.Now, changes described input current and becomes an output voltage to export, and sample described input current, to export as a correcting current.After correcting current is compared with reference current signal and reference voltage respectively with output voltage, produce an offset current signal via current compensation circuit and voltage compensating circuit and produce a bucking voltage signal, the pulse wave width modulation signal of renewal can be produced accordingly, make alternating voltage identical with the phase place of input current.Wherein reference current signal is multiplied with bucking voltage signal by offset current signal by the multiplicative gain device of connection two compensator and obtains it.Finally, receive offset current signal and bucking voltage signal, to produce the pulse wave width modulation signal of renewal accordingly, make alternating voltage identical with the phase place of input current.

Receive described correcting current, and after it being compared with described reference current signal, to produce the step of described offset current signal, more comprise the following step: receive described correcting current and described reference current signal, after both this relatively, export one and compare electric current; And receive and describedly compare electric current, after carrying out current compensation, produce described offset current signal.

Receive described output voltage, and after it is compared with described reference voltage, to produce the step of described bucking voltage signal, more comprise the following step: receive described output voltage, produce a feedback voltage with dividing potential drop; Receive described feedback voltage and described reference voltage, after both this relatively, export a comparative voltage; And receive described comparative voltage, after carrying out voltage compensation, produce described bucking voltage signal.

Described reference current signal be by described offset current signal, a current gain be multiplied with described bucking voltage signal and obtain step, more comprise the following step: receive described offset current signal and described bucking voltage signal, after being multiplied, produce a Compensation Feedback electric current; And receive described Compensation Feedback electric current, after being multiplied by described current gain, produce described reference current signal.

Receive described offset current signal and described bucking voltage signal, to produce the step of the described pulse wave width modulation signal of described renewal accordingly, more comprise the following step: receive described bucking voltage signal, to produce an oblique wave signal accordingly; And receive described oblique wave signal and described offset current signal, after comparing, export the described pulse wave width modulation signal of described renewal.When the magnitude of voltage of described oblique wave signal is greater than magnitude of voltage corresponding to described offset current signal, described pulse wave width modulation signal is high levle voltage; And the magnitude of voltage of described oblique wave signal is when being less than magnitude of voltage corresponding to described offset current signal, described pulse wave width modulation signal is low level voltage.

Sample described input current, using in the step exported as described correcting current, utilize a sample resistance, sample described input current, to export as described correcting current.

Described sample resistance, described pulse wave width modulation signal, described input current, described alternating voltage, described output voltage and described oblique wave signal meet following condition:

R _S·i _in(θ)＝d _OFF(θ)·T _S.W.·S _V；

D _oFF(θ)=V _{in_pk}sin (θ)/V _o=1-d (θ); And

I _in(θ)=V _{in_pk}sin (θ)/R _{in (ac)}, wherein R _sfor the resistance of described sample resistance, i _in(θ) be described input current, V _{in_pk}sin (θ) is described alternating voltage, V _ofor described output voltage, S _vfor the slope of described oblique wave signal, R _{in (ac)}for equivalent inpnt AC resistance, T _s.W.with cycle and duty ratio that d (θ) is described pulse wave width modulation signal respectively.

The invention has the beneficial effects as follows, provide a kind of power factor correcting device and bearing calibration thereof, a multiplier is utilized to connect current compensation circuit and voltage compensating circuit, be multiplied with offset current signal with the bucking voltage signal that two compensators are exported, and then obtain the technology of the reference current signal being supplied to current compensation circuit, carry out Active PFC, this technology can avoid the technology utilizing integrating capacitor simultaneously, and the response speed of internal circuit when operating significantly is promoted, to promote power factor (PF) correction usefulness.

Hereby further understand and understanding for making your juror more have architectural feature of the present invention and effect of reaching, careful assistant is with preferred embodiment figure and coordinate detailed description, illustrates as rear:

Accompanying drawing explanation

Fig. 1 is means for correcting circuit diagram of the present invention;

Fig. 2 is the transfer function calcspar of means for correcting of the present invention;

Fig. 3 is bearing calibration flow chart of the present invention;

Fig. 4 is each signal waveform figure of the present invention;

Fig. 5 is reference current signal of the present invention, offset current signal and bucking voltage signal waveform amplification figure;

Fig. 6 is oblique wave signal of the present invention, offset current signal and pulse wave width modulation signal waveform figure;

Fig. 7 is alternating voltage and the input current waveform figure thereof of 220 volts of the present invention;

Fig. 8 is alternating voltage and the input current waveform figure thereof of 110 volts of the present invention.

Description of reference numerals: 10-load; 12-power stage circuit; 14-current compensation circuit; 16-voltage compensating circuit; 18-multiplicative gain device; 20-pulse wave width modulation transducer; 22-sample resistance; 24-AC/DC changeover switch; 241-inductor; 243-power transistor 245-power diode; 26-current error amplifier; 28-current compensator; 30-voltage divider; 32-voltage error amplifier; 34-voltage compensator; 36-multiplier; 38-current gain adjuster; 40-ramp generator; 42-changes comparator.

Embodiment

Below in conjunction with accompanying drawing, to above-mentioned being described in more detail with other technical characteristic and advantage of the present invention.

Refer to Fig. 1.Power factor correcting device of the present invention connects a load 10, and comprises a power stage circuit 12, connects load 10, and receives an alternating voltage V _aCwith a pulse wave width modulation signal V _pWM, with according to this pulse wave width modulation signal V _pWMconversion alternating voltage V _aCbe an input current I _aC, and exported to load 10, make load 10 to produce an output voltage V _o, and sample input current I _aC, using as a correcting current I _senexport.Power stage circuit 12 connects current compensation circuit 14 and a voltage compensating circuit 16.Current compensation circuit 14 receives correcting current I _senwith a reference current signal I _ref, and by both this relatively after, produce an offset current signal I _eA.Voltage compensating circuit 16 receives output voltage V _owith a reference voltage V _ref, and by both this relatively after, produce a bucking voltage signal V _eA.Current compensation circuit 14 and voltage compensating circuit 16 are all connected multiplicative gain device 18 and a pulse wave width modulation transducer 20.Multiplicative gain device 18 receives offset current signal I _eAwith bucking voltage signal V _eA, after being multiplied, produce reference current signal I _ref.Pulse wave width modulation transducer 20, then receive offset current signal I _eAwith bucking voltage signal V _eA, to produce pulse wave width modulation signal V _pWM, make alternating voltage V _aCwith input current I _aCphase place identical.

Power stage circuit 12 more comprises sample resistance 22 and an AC/DC changeover switch 24, and AC/DC changeover switch 24 comprises inductor 241, power transistor 243 and a power diode 245.Sample resistance 22 connects current compensation circuit 14, and AC/DC changeover switch 24 connects load 10, sample resistance 22, current compensation circuit 14 and voltage compensating circuit 16.AC/DC changeover switch 24 receives alternating voltage V _aCwith pulse wave width modulation signal V _pWM, and by inductor 241, power transistor 243 and a power diode 245, come according to pulse wave width modulation signal V _pWMconversion alternating voltage V _aCfor input current I _aC, and exported to load, to produce output voltage V _o, utilize again sample resistance 22 to sample input current I _aC, to export above-mentioned correcting current I _sen.

Current compensation circuit 14 more comprises current error amplifier 26 and a current compensator 28.Current error amplifier 26 connects the sample resistance 22 of power stage circuit 12, and receives correcting current I _senwith a reference current signal I _ref, after both this relatively, export one and compare electric current.Current compensator 28 connects current error amplifier 26, and electric current is compared in reception, after carrying out current compensation, produces offset current signal I _eA.Voltage compensating circuit 16 more comprises a voltage divider 30, connects the AC/DC changeover switch 24 of power stage circuit 12, and receives output voltage V _o, produce a feedback voltage V with dividing potential drop _fB.Voltage divider 30 connects a voltage error amplifier 32, receives feedback voltage V _fBwith reference voltage V _ref, after both this relatively, export a comparative voltage.Voltage error amplifier 32 connects a voltage compensator 34, receives comparative voltage, after carrying out voltage compensation, produces bucking voltage signal V _eA.

Multiplicative gain device 18 more comprises multiplier 36 and a current gain adjuster 38.Multiplier 36 connects the current compensator 28 of current compensation circuit 14 and the voltage compensator 34 of voltage compensating circuit 16, and receives offset current signal I _eAwith bucking voltage signal V _eA, after being multiplied, produce a Compensation Feedback electric current.Multiplier 36 more connects current gain adjuster 38, receives Compensation Feedback electric current, is multiplied by a current gain K _mafter, produce reference current signal I _ref.

Pulse wave width modulation transducer 20 more comprises a ramp generator 40, connects the voltage error amplifier 32 of voltage compensating circuit 16, and receives bucking voltage signal V _eA, to produce an oblique wave signal V accordingly _rAMP.Ramp generator 40 is connected a conversion comparator 42 with the current error amplifier 26 of current compensation circuit 14, receives oblique wave signal V _rAMPwith offset current signal I _eA, after comparing, export pulse wave width modulation signal V _pWMto in the AC/DC changeover switch 24 of power stage circuit 12.Wherein, as oblique wave signal V _rAMPmagnitude of voltage be greater than offset current signal I _eAduring corresponding magnitude of voltage, pulse wave width modulation signal V _pWMfor high levle voltage; As oblique wave signal V _rAMPmagnitude of voltage be less than offset current signal I _eAduring corresponding magnitude of voltage, pulse wave width modulation signal V _rAMPfor low level voltage.

In order to make alternating voltage identical with the phase place of input current, effectively to reach the object of power factor (PF) correction, sample resistance, pulse wave width modulation signal V _pWM, input current I _aC, alternating voltage V _aC, output voltage V _owith oblique wave signal V _rAMPfollowing condition must be met:

R _S·i _in(θ)＝d _OFF(θ)·T _S.W.·S _V(1)

d _OFF(θ)＝V _{in_pk}·sin(θ)/V _o＝1-d(θ) (2)

i _in(θ)＝V _{in_pk}·sin(θ)/R _in(ac)(3)

Wherein i _in(θ) input current I is _aC, V _{in_pk}sin (θ) is alternating voltage V _aC, S _vfor oblique wave signal V _rAMPslope, R _{in (ac)}for equivalent inpnt AC resistance _,t _s.W.with d (θ) for distinguishing pulse wave width modulation signal V _pWMcycle and duty ratio (duty cycle).Formula (4), (5) can be obtained by above-mentioned formula (1), (2), (3):

$i_{\mathrm{in}}\left(\mathrm{\θ}\right)=\frac{V_{\mathrm{in}\_\mathrm{pk}}}{R_{\mathrm{in}\left(\mathrm{ac}\right)}}\·\sin \left(\mathrm{\θ}\right)---\left(4\right)$

$R_{\mathrm{in}\left(\mathrm{ac}\right)}=\frac{R_S\·V_o}{T_{s.w}\·S_V}---\left(5\right)$

From formula (5), R _{in (ac)}be a constant, alternating voltage therefore can be made identical with input current phase place, to reach the object of Active PFC.

Below introduce input power P _in, offset current signal I _eA, bucking voltage signal V _eA, oblique wave signal V _rAMPslope S _v, oblique wave signal V _rAMPcrest voltage V _pmax:

$I_{\mathrm{AC}}\≅\frac{{2P}_{\mathrm{in}}}{V_{\mathrm{AC}}}---\left(6\right)$

$V_{\mathrm{EA}}\≅\frac{{2P}_{\mathrm{in}}\·R_S\·V_o}{K_{\mathrm{multi}}\·V_{\mathrm{AC}}^2}---\left(7\right)$

$S_V\≅\frac{V_{\mathrm{EA}}\·g_{\mathrm{mv}}}{C_S}\·T_{S.W.}---\left(8\right)$

$I_{\mathrm{EA}}\≅\frac{2P_{\mathrm{in}}\·R_S\·g_{\mathrm{mv}}\·T_{S.W.}}{K_{\mathrm{multi}}\·V_{\mathrm{AC}}\·C_S}---\left(9\right)$

$V_{p\max }\≅I_{\mathrm{EA}\max }\frac{V_o}{V_{\mathrm{AC}\min }}---\left(10\right)$

At formula (6) in formula (10), K _multifor the multiplicative gain of multiplier 36, g _mvfor the gain of voltage error amplifier 32, C _sfor the capacitance of the internal capacitor of ramp generator 40, I _eAmaxfor offset current signal I _eAlowest high-current value, V _aCminfor the minimum value of alternating voltage.

Then introduce offset current signal I _eAwith bucking voltage signal V _eAbe multiplied, obtain reference current signal I _refcomputational process:

$\begin{array}{c}\frac{1}{Z_{\mathrm{comp}}}\·{\∫}_0^{\mathrm{\π}/2}(R_S\·i_{\mathrm{in}}\left(\mathrm{\θ}\right)-K_m\·(d_{\mathrm{OFF}}\left(\mathrm{\θ}\right)\·T_{S.W.}\·S_V\·V_o\·K_v))\mathrm{d\θ}\\ =d_{\mathrm{OFF}}\left(\mathrm{\θ}\right)\·T_{S.W.}\·S_V\\ \⇒i_{\mathrm{in}}\left(\mathrm{\θ}\right)=\frac{T_{S.W.}\·S_V}{R_S}[K_m(d_{\mathrm{OFF}}\left(\mathrm{\θ}\right)\·V_o\·K_v)+Z_{\mathrm{comp}}\·\frac{d}{\mathrm{d\θ}}\·d_{\mathrm{OFF}}\left(\mathrm{\θ}\right)]\\ \⇒i_{\mathrm{in}}\left(\mathrm{\θ}\right)=\frac{T_{S.W.}\·S_V}{R_S}\·\frac{V_{\mathrm{in}\_\mathrm{pk}}}{V_o}(K_m\·V_o\·K_v\·\sin \left(\mathrm{\θ}\right)+Z_{\mathrm{comp}}\·\cos \left(\mathrm{\θ}\right))\\ \⇒K_m\·V_o\·K_v>>i_{\mathrm{in}}\left(\mathrm{\θ}\right)=\frac{T_{S.W.}\·S_V\·V_{\mathrm{in}\_\mathrm{pk}}\·K_m\·K_v}{R_S}\·\sin \left(\mathrm{\θ}\right)\\ \⇒i_{\mathrm{in}}\left(\mathrm{\θ}\right)=\frac{V_{\mathrm{in}\_\mathrm{pk}}}{R_{\mathrm{in}\left(\mathrm{ac}\right)}}\·\sin \left(\mathrm{\θ}\right)\\ \⇒R_{\mathrm{in}\left(\mathrm{ac}\right)}=\frac{R_S}{T_{s.w}\·S_V\·K_m\·K_v}\end{array}$

In above-mentioned computational process, K _vfor the dividing ratios of voltage divider 30, Z _compfor the impedance of current compensator 28.From above-mentioned computational process, the present invention does not need to sample input voltage, and mainly utilizes offset current signal I _eAwith bucking voltage signal V _eA, obtain reference current signal I _ref, and then reaching power factor (PF) correction, this method can avoid the technology using integrating capacitor simultaneously, and the response speed of internal circuit when operating significantly is promoted, to promote power correction usefulness.

Below introduce bearing calibration of the present invention, please refer to Fig. 2 and Fig. 3, wherein Gv (s) is the transfer function of voltage compensator 34, and Gi (s) is the transfer function of current compensator 28, Gid (s) is the transfer function of AC/DC changeover switch 24, K _pWMfor the transfer function of pulse wave width modulation transducer 20.

First, as shown in step S10, the AC/DC changeover switch 24 of power stage circuit 12 receives alternating voltage V _aCwith pulse wave width modulation signal V _pWM, with according to this pulse wave width modulation signal V _pWMconversion alternating voltage V _aCfor input current I _aC.Then, as shown in step S12, the AC/DC changeover switch 24 of power stage circuit 12 changes input current I _aCbecome output voltage V _oexport, and utilize sample resistance 22 to sample input current I _aC, using as correcting current I _senexport.Then, as shown in step S14, current compensation circuit 14 and voltage compensating circuit 16 receive correcting current I respectively _senwith output voltage V _o, current compensation circuit 14 is by correcting current I _senwith reference current signal I _refrelatively, to produce offset current signal I _eA, and voltage compensating circuit 16 is by output voltage V _owith reference voltage V _refrelatively, to produce bucking voltage signal V _eA, wherein reference current signal I _refreceive above-mentioned offset current signal I by multiplicative gain device 18 _eAwith bucking voltage signal V _eA, obtained it to be multiplied.

Finally, as shown in step S16, pulse wave width modulation transducer 20 receives offset current signal I _eAwith bucking voltage signal V _eA, to produce the pulse wave width modulation signal V of renewal accordingly _pWM, and this is sent in power stage circuit 12, then, be back to step S10, again sequentially carry out step S10, S12, S14, S16, make alternating voltage identical with the phase place of input current.

In above-mentioned flow process, the current compensation circuit 14 in step S14 receives correcting current I _sen, and by itself and reference current signal I _refrelatively, to produce offset current signal I _eAstep, more can implement it by the following step: first, current error amplifier 26 receives correcting current I _senwith reference current signal I _ref, after both this relatively, export and compare electric current.Then, current compensator 28 receives this and compares electric current, after carrying out current compensation, produces offset current signal I _eA.Separately, voltage compensating circuit 16 receives output voltage V _o, and by itself and reference voltage V _refrelatively, to produce bucking voltage signal V _eAstep, more can implement it by the following step: first, voltage divider 30 receives output voltage V _o, produce a feedback voltage with dividing potential drop.Then, voltage error amplifier 32 receives feedback voltage and reference voltage V _ref, after both this relatively, export comparative voltage.Finally, voltage compensator 34 receives comparative voltage, after carrying out voltage compensation, produces bucking voltage signal V _eA.In addition, reference current signal I _refreceive above-mentioned offset current signal I by multiplicative gain device 18 _eAwith bucking voltage signal V _eA, obtained to be multiplied step, can also be implemented it by the following step: first multiplier 36 receives offset current signal I _eAwith bucking voltage signal V _eA, after being multiplied, produce Compensation Feedback electric current.Then, current gain adjuster 38 receives Compensation Feedback electric current, is multiplied by current gain K _mafter, produce reference current signal I _ref.

In step s 16, more can implement it by the following step: first, ramp generator 40 receives bucking voltage signal V _eA, to produce oblique wave signal V accordingly _rAMP.Then, change comparator 42 and receive oblique wave signal V _rAMPwith offset current signal I _eA, after comparing, export the pulse wave width modulation signal V upgraded _pWMto power stage circuit 12.

At above-mentioned each main signal, as reference current signal I _ref, bucking voltage signal V _eA, feedback voltage V _fB, alternating voltage V _aC, offset current signal I _eAwith oblique wave signal V _rAMPoscillogram as shown in Figure 4, wherein, reference current signal I in correspondence with each other _ref, offset current signal I _eAwith bucking voltage signal V _eAafter amplification, be showed in Fig. 5.

In the transfer process of conversion comparator 42, as oblique wave signal V _rAMPmagnitude of voltage be greater than offset current signal I _eAduring corresponding magnitude of voltage, pulse wave width modulation signal V _pWMfor high levle voltage; As oblique wave signal V _rAMPmagnitude of voltage be less than offset current signal I _eAduring corresponding magnitude of voltage, pulse wave width modulation signal V _rAMPfor low level voltage, as shown in Figure 6.

Refer to Fig. 7 and Fig. 8, Fig. 7 is the alternating voltage V of 220 volts of the present invention _aCand input current I _aCoscillogram; Fig. 8 is then the alternating voltage V of 110 volts of the present invention _aCand input current I _aCoscillogram, this two figure be all means for correcting of the present invention the oscillogram of testing out, as seen from the figure, the present invention can make alternating voltage V really _aCand input current same-phase, reach the object of Active PFC.

In sum, the present invention utilizes multiplicative gain device received current compensating signature and a voltage compensation signal, produces the reference current signal being supplied to current compensation circuit, and then revises the power factor (PF) of input signal.

More than illustrate just illustrative for the purpose of the present invention, and nonrestrictive, and those of ordinary skill in the art understand; when not departing from the spirit and scope that following claims limit, many amendments can be made, change; or equivalence, but all will fall within the scope of protection of the present invention.

Claims (16)

1. a power factor correcting device, is characterized in that, connects a load, and described power factor correcting device comprises:

One power stage circuit, connect described load, and receive an alternating voltage and a pulse wave width modulation signal, to change described alternating voltage into an input current according to described pulse wave width modulation signal, and exported to described load, make described load produces an output voltage, and sample described input current to export as a correcting current;

One current compensation circuit, connects described power stage circuit, to receive and more described correcting current and a reference current signal, to produce an offset current signal;

One voltage compensating circuit, connects described power stage circuit, to receive and more described output voltage and a reference voltage, to produce a bucking voltage signal;

One multiplicative gain device, connects described current compensation circuit and described voltage compensating circuit, and receives described offset current signal and described bucking voltage signal, after being multiplied, then is multiplied by a current gain, produces described reference current signal; And

One pulse wave width modulation transducer, connect described current compensation circuit and described voltage compensating circuit, and receive described offset current signal and described bucking voltage signal, to produce described pulse wave width modulation signal, make described alternating voltage identical with the phase place of described input current.

2. power factor correcting device as claimed in claim 1, it is characterized in that, described power stage circuit more comprises:

One sample resistance, connects described current compensation circuit; And

One AC/DC changeover switch, connect described load, described sample resistance, described current compensation circuit and described voltage compensating circuit, and receive described alternating voltage and described pulse wave width modulation signal, to change described alternating voltage into described input current according to described pulse wave width modulation signal, and exported to described load, to produce described output voltage, described sample resistance is utilized again to sample described input current, to export described correcting current.

3. power factor correcting device as claimed in claim 1, it is characterized in that, described current compensation circuit more comprises:

One current error amplifier, connects described power stage circuit, and receives described correcting current and a reference current signal, after both this relatively, exports one and compares electric current; And

One current compensator, connects described current error amplifier, and receives and describedly compare electric current, after carrying out current compensation, produces described offset current signal.

4. power factor correcting device as claimed in claim 1, it is characterized in that, described voltage compensating circuit more comprises:

One voltage divider, connects described power stage circuit, and receives described output voltage, produces a feedback voltage with dividing potential drop;

One voltage error amplifier, connects described voltage divider, and receives described feedback voltage and described reference voltage, after both this relatively, exports a comparative voltage; And

One voltage compensator, connects described voltage error amplifier, and receives described comparative voltage, after carrying out voltage compensation, produces described bucking voltage signal.

5. power factor correcting device as claimed in claim 1, it is characterized in that, described multiplicative gain device more comprises:

One multiplier, connects described current compensation circuit and described voltage compensating circuit, and receives described offset current signal and described bucking voltage signal, after being multiplied, produces a Compensation Feedback electric current; And

One current gain adjuster, connects described multiplier, and receives described Compensation Feedback electric current, after being multiplied by described current gain, produces described reference current signal.

6. power factor correcting device as claimed in claim 2, it is characterized in that, described pulse wave width modulation transducer more comprises:

One ramp generator, connects described voltage compensating circuit, and receives described bucking voltage signal, to produce an oblique wave signal accordingly; And

One conversion comparator, connects described ramp generator and described current compensation circuit, and receives described oblique wave signal and described offset current signal, after comparing, exports in described pulse wave width modulation signal to described power stage circuit.

7. power factor correcting device as claimed in claim 6, is characterized in that, when the magnitude of voltage of described oblique wave signal is greater than magnitude of voltage corresponding to described offset current signal, described pulse wave width modulation signal is high levle voltage; And the magnitude of voltage of described oblique wave signal is when being less than magnitude of voltage corresponding to described offset current signal, described pulse wave width modulation signal is low level voltage.

8. power factor correcting device as claimed in claim 7, it is characterized in that, described sample resistance, described pulse wave width modulation signal, described input current, described alternating voltage, described output voltage and described oblique wave signal meet following condition:

R _S·i _in(θ)＝d _OFF(θ)·T _S.W.·S _V；

D _oFF(θ)=V _{in_pk}sin (θ)/V _o=1-d (θ); And

I _in(θ)=V _{in_pk}sin (θ)/R _{in (ac)}, wherein R _sfor the resistance of described sample resistance, i _in(θ) be described input current, V _{in_pk}sin (θ) is described alternating voltage, V _ofor described output voltage, S _vfor the slope of described oblique wave signal, R _{in (ac)}for equivalent inpnt AC resistance, T _s.W.with cycle and duty ratio that d (θ) is described pulse wave width modulation signal respectively.

9. a power factor calibrating method, is characterized in that, comprises the following step:

Receive an alternating voltage and a pulse wave width modulation signal, to change described alternating voltage into an input current according to described pulse wave width modulation signal;

Changing described input current becomes an output voltage to export, and samples described input current, to export as a correcting current:

Receive described correcting current and described output voltage, after described correcting current is compared with a reference current signal, to produce an offset current signal, and after described output voltage is compared with a reference voltage, to produce a bucking voltage signal, wherein said reference current signal is multiplied with described bucking voltage signal by described offset current signal, a current gain and obtains it; And

Receive described offset current signal and described bucking voltage signal, to produce the described pulse wave width modulation signal of renewal accordingly, make described alternating voltage identical with the phase place of described input current.

10. power factor calibrating method as claimed in claim 9, is characterized in that, receive described correcting current, and after it being compared with described reference current signal, to produce the step of described offset current signal, more comprise the following step:

Receive described correcting current and described reference current signal, after both this relatively, export one and compare electric current; And

Receive and describedly compare electric current, after carrying out current compensation, produce described offset current signal.

11. power factor calibrating methods as claimed in claim 9, is characterized in that, receive described output voltage, and after it being compared with described reference voltage, to produce the step of described bucking voltage signal, more comprise the following step:

Receive described output voltage, produce a feedback voltage with dividing potential drop;

Receive described feedback voltage and described reference voltage, after both this relatively, export a comparative voltage; And

Receive described comparative voltage, after carrying out voltage compensation, produce described bucking voltage signal.

12. power factor calibrating methods as claimed in claim 9, is characterized in that, described reference current signal be by described offset current signal, described current gain be multiplied with described bucking voltage signal and obtain step, more comprise the following step:

Receive described offset current signal and described bucking voltage signal, after being multiplied, produce a Compensation Feedback electric current; And

Receive described Compensation Feedback electric current, after being multiplied by described current gain, produce described reference current signal.

13. power factor calibrating methods as claimed in claim 9, is characterized in that, receive described offset current signal and described bucking voltage signal, to produce the step of the described pulse wave width modulation signal of described renewal accordingly, more comprise the following step:

Receive described bucking voltage signal, to produce an oblique wave signal accordingly; And

Receive described oblique wave signal and described offset current signal, after comparing, export the described pulse wave width modulation signal of described renewal.

14. power factor calibrating methods as claimed in claim 13, is characterized in that, when the magnitude of voltage of described oblique wave signal is greater than magnitude of voltage corresponding to described offset current signal, described pulse wave width modulation signal is high levle voltage; And the magnitude of voltage of described oblique wave signal is when being less than magnitude of voltage corresponding to described offset current signal, described pulse wave width modulation signal is low level voltage.

15. power factor calibrating methods as claimed in claim 13, is characterized in that, sample described input current, using in the step exported as described correcting current, utilize a sample resistance, sample described input current, to export as described correcting current.

16. power factor calibrating methods as claimed in claim 15, is characterized in that, described sample resistance, described pulse wave width modulation signal, described input current, described alternating voltage, described output voltage and described oblique wave signal meet following condition:

R _S·i _in(θ)＝d _OFF(θ)·T _S.W.·S _V；

D _oFF(θ)=V _{in_pk}sin (θ)/V _o=1-d (θ); And

I _in(θ)=V _{in_pk}sin (θ)/R _{in (ac)}, wherein R _sfor the resistance of described sample resistance, i _in(θ) be described input current, V _{in_pk}sin (θ) is described alternating voltage, V _ofor described output voltage, S _vfor the slope of described oblique wave signal, R _{in (ac)}for equivalent inpnt AC resistance, T _s.W.with cycle and duty ratio that d (θ) is described pulse wave width modulation signal respectively.