CN103825475A - Circuit and control method for improving vehicle-mounted charger power factor - Google Patents

Abstract

The invention discloses a circuit and control method for improving a vehicle-mounted charger power factor. The circuit comprises an AC input power supply, and a DC output terminal, wherein the positive and negative two ends of the DC output terminal are connected with the two ends of a bridge rectifier respectively, the bridge rectifier converting AC electric energy of the AC input power supply into DC electric energy which is then supplied to the DC output terminal. The other end of a first inductor is connected to the positive pole of the DC output terminal through a first switch tube and connected to the negative pole of the DC output terminal through a second switch tube. The other end of a second inductor is connected to the positive pole of the DC output terminal through a third switch tube and connected to the negative pole of the DC output terminal through a fourth switch tube. According to the circuit for improving the vehicle-mounted charger power factor, the efficiency of PFC is more than 97.5%, and reaches 98% when the output power is 2.2 KW.

Description

Improve circuit and the control method of Vehicular charger power factor

Technical field

The present invention relates to the vehicle-mounted charger power factor control method of a kind of electric automobile, particularly a kind of the vehicle-mounted charger power factor control method of electric automobile and interlock circuit efficiently.

Background technology

Power factor correction (PowerFactorCorrection, PFC) has become the focus in power electronics industry.Bridgeless Boost pfc circuit has omitted input rectifying bridge with respect to traditional power factor correction circuit, not only can save space, significantly reduce again conduction loss simultaneously, efficiency improves approximately 3%～4%, particularly in high-power, large electric current application scenario, there is obvious odds for effectiveness, there is the prospect of commercial Application, cannot Direct Sampling but do not adopt rectifier bridge to make conventional P FC control required input half-wave sinusoidal voltage because of non-bridge PFC.And the periodicity of inductive current direction conversion brings difficulty also to the detection of electric current, increase the design difficulty of bridgeless Boost PFC control circuit.

Need at present the urgent technical problem solving of those skilled in the art to be exactly: how can innovate and to propose the more efficient Vehicular charger power factor control method of one, to solve the deficiencies in the prior art, effectively realize the Method and circuits device without the control of bridge interleaving PFC.

Summary of the invention

The present invention is directed to the drawback of prior art, provide a kind of Vehicular charger power factor circuit device of the present invention can make the efficiency of PFC more than 97.5%, in the time that power output is 2.2KW, reach 98% circuit and control method.And the efficiency of PFC is generally 75% left and right in prior art.

For this reason, the invention discloses a kind of control method of Vehicular charger power factor efficiency, the method comprises: input waveform is carried out to digitlization, and detect the zero crossing of inductive current, and improve sinusoidal envelope fiducial value.

Whether the waveform that judges input is positive half cycle;

If positive half cycle, the electric current on inductance is flow through in detection, in the time the current zero-crossing point of inductance being detected, open second switch pipe, for induction charging, in the time that reaching envelope ripple, turn-offs in detection electric current second switch pipe, described inductive discharge, until inductance zero crossing again detected, again open second switch pipe;

When same negative half period, the electric current on inductance is flow through in detection, in the time the current zero-crossing point of inductance being detected, open the first switching tube, for induction charging, in the time that reaching envelope ripple, turn-offs in detection electric current the first switching tube, described inductive discharge, until inductance zero crossing again detected, again open the first switching tube;

Further, described input waveform is 85V-264V, the alternating current of 50HZ

Further, calculating second switch pipe opens to the time T of disconnection, and control the 4th switching tube T/2 after the action of second switch pipe follows second switch pipe and opens or disconnect.

Further, calculating the first switching tube opens to the time T of disconnection, and control the 3rd switching tube T/2 after the first switching tube action follows the first switching tube and opens or disconnect.

Further, employing complex programmable logic device (CPLD) detects crossover point signal and reaches the cut-off signal of envelope ripple, control opening and disconnecting of four switching tubes, and calculating first or second switch pipe open to the time T of disconnection, the pwm signal that wherein forms envelope waveform is crucial, realizes and to do High Power Factor.

In other words, the invention provides a kind of circuit that improves Vehicular charger power factor, wherein, comprising:

Alternating current input power supplying, the one utmost point is connected to bridge rectifier, and another utmost point first inductor in parallel with two is connected with one end of the second inductor;

DC output end, its positive and negative polarities are connected with the two ends of bridge rectifier respectively, by bridge rectifier, the AC energy of alternating current input power supplying are converted to direct current energy and offer DC output end;

The other end of the first inductor is connected to respectively the positive pole of DC output end by the first switching tube, be connected to the negative pole of DC output end by second switch pipe; The other end of the second inductor is connected to respectively the positive pole of DC output end by the 3rd switching tube, be connected to the negative pole of DC output end by the 4th switching tube;

Wherein, when the voltage of alternating current input power supplying input is during in positive half cycle, second switch pipe and the operation of the 4th switching tube linked switch, and the first switching tube and the 3rd switching tube are in off-state; When the voltage of alternating current input power supplying input is during in negative half period, the first switching tube and the operation of the 3rd switching tube linked switch, and second switch pipe and the 4th switching tube are in off-state.

Preferably, in the circuit of described raising Vehicular charger power factor, described bridge rectifier comprises that anodal negative pole joins end to end, forms four diodes of loop, and a utmost point of described alternating current input power supplying is connected between the second diode and the 3rd diode and between the 4th diode and the first diode; Wherein, the positive pole of DC output end is connected between the first diode and the second diode; The negative pole of DC output end is connected between the 3rd diode and the 4th diode.

Preferably, in the circuit of described raising Vehicular charger power factor, between another utmost point of alternating current input power supplying and the first inductor and the link of the second inductor, be provided with galvanometer, and a utmost point of alternating current input power supplying is directly connected to the positive pole of DC output end by the 5th diode, wherein the side of the positive electrode of diode is positioned at alternating current input power supplying one side, and a utmost point of alternating current input power supplying is also directly connected to the negative pole of DC output end by the 6th diode, wherein the negative side of the 6th diode is positioned at alternating current input power supplying one side.

Preferably, in the circuit of described raising Vehicular charger power factor, also comprise zero-crossing detection circuit, its influence value using induction coil corresponding to the first inductor is as input value, utilizes voltage comparator to detect whether zero crossing of the first inductor current.

Preferably, in the circuit of described raising Vehicular charger power factor, also comprise the first inductive current detection circuit, it judges according to input voltage signal and power factor correction pulse current whether the first inductive current reaches envelope value.

According to another aspect of the present invention, carry out the control method of power factor according to the circuit of above-mentioned raising Vehicular charger power factor, wherein, comprise the following steps:

Step 1, the voltage waveform that alternating current input power supplying is inputted carry out digitlization, and the waveform that judges input AC electricity is positive half cycle or negative half period;

The electric current on the first inductance is flow through in step 2, detection;

If positive half cycle, when detect on the first inductance current zero-crossing point time, connect second switch pipe, be the first induction charging, when detecting that electric current disconnects second switch pipe while reaching envelope ripple, described the first inductive discharge, until current zero-crossing point again detected, again connect second switch pipe;

If negative half period, when detect on the first inductance current zero-crossing point time, connect the first switching tube, be the first induction charging, in the time that detection electric current reaches envelope ripple, disconnect the first switching tube, described the first inductive discharge, until current zero-crossing point again detected, again connect the first switching tube.

Preferably, in the control method of described raising Vehicular charger power factor efficiency, further comprising the steps of:

Calculate T cycle time that one of the first switching tube is switched to disconnection, control the 3rd switching tube T/2 time after the back to back next action cycle of the first switching tube starts and rise, follow the first switching tube and carry out on or off operation.

Preferably, in the control method of described raising Vehicular charger power factor efficiency, further comprising the steps of:

Calculate T cycle time that one of second switch pipe is switched to disconnection, control the 4th switching tube T/2 time after the back to back next action cycle of second switch pipe starts and rise, follow second switch pipe and carry out on or off operation.

The invention has the beneficial effects as follows the control method that a kind of efficient Vehicular charger power factor efficiency is provided, solved the deficiencies in the prior art.Wherein, input waveform is carried out to digitized processing and solve the problem that input half-wave sinusoidal voltage cannot Direct Sampling, and utilize software control zero crossing to detect to have overcome the periodicity of inductive current direction to convert the detection difficult of bringing.

Accompanying drawing explanation

Fig. 1 is the circuit diagram that the present invention improves Vehicular charger power factor;

Fig. 2 is that the present invention inputs in positive half cycle situation at voltage, second switch pipe switch on and off alternation produce the first inductance on current waveform schematic diagram;

Fig. 3 (a) inputs in positive half cycle situation at voltage for the present invention, the current trend schematic diagram in second switch pipe connection situation;

Fig. 3 (b) inputs in positive half cycle situation at voltage for the present invention, the current trend schematic diagram under second switch pipe disconnection;

Fig. 3 (c) is that the present invention inputs in negative half period situation at voltage, the current trend schematic diagram in the first switching tube connection situation;

Fig. 3 (d) is that the present invention inputs in negative half period situation at voltage, the current trend schematic diagram under the first switching tube disconnection;

Fig. 4 is the circuit theory diagrams that in the present invention's the first inductance, current zero-crossing point detects;

Fig. 5 (a) and Fig. 5 (b) are current detection circuit in the present invention's the first inductance;

Fig. 6 is the control principle flow chart of the present invention's circuit of improving Vehicular charger power factor;

Fig. 7 is the efficiency chart of different output power of the present invention.

embodiment

Below in conjunction with accompanying drawing, the present invention is described in further detail, to make those skilled in the art can implement according to this with reference to specification word.

In order to make object of the present invention, technical scheme and advantage clearer, below in conjunction with accompanying drawing, the realization of the control method to Vehicular charger power factor efficiency of the present invention is further elaborated.Should be appreciated that specific embodiment described herein, only in order to explain the present invention, is not intended to limit the present invention.

What power factor circuit device of the present invention adopted is active without bridge interleaving PFC topology, and this is approach 1 power factor and very low THD value but also can adapt to wide range input because active PFC circuit not only can reach.Active PFC circuit output voltage is generally high pressure 400V left and right, can meet with less electrochemical capacitor the requirement of output voltage retention time.Also be conducive to reduce the loss of rear class DC/DC circuit simultaneously.That studies herein actively just belongs to a kind of high power, low-loss active PFC circuit without bridge interleaving PFC circuit, and concrete have two groups of metal-oxide-semiconductors as Fig. 1 in circuit, and each organizes metal-oxide-semiconductor alternate conduction.Circuit comprises alternating current input power supplying, and the one utmost point is connected to bridge rectifier PB3008, and another utmost point first inductor L102 in parallel with two is connected with one end of the second inductor L103;

DC output end, its positive and negative polarities ZK ₊be connected with the two ends of bridge rectifier respectively with ZK, by bridge rectifier PB3008, the AC energy of alternating current input power supplying be converted to direct current energy and offer DC output end;

The other end of the first inductor L102 is connected to respectively the anodal HL of DC output end by the first switch transistor T 101, be connected to the negative pole of DC output end by second switch pipe T100; The other end of the second inductor L103 is connected to respectively the positive pole of DC output end by the 3rd switch transistor T 103, be connected to the negative pole of DC output end by the 4th switch transistor T 102;

Wherein, when the voltage of alternating current input power supplying input is during in positive half cycle, second switch pipe and the operation of the 4th switching tube linked switch, and the first switching tube and the 3rd switching tube are in off-state; When the voltage of alternating current input power supplying input is during in negative half period, the first switching tube and the operation of the 3rd switching tube linked switch, and second switch pipe and the 4th switching tube are in off-state.Switching tube can be metal-oxide-semiconductor.

The active mode of operation without bridge interleaving PFC of the present invention is critical discontinuous mode.Critical interrupted and continuous pattern control is a kind of control mode of variable mode, and to be after on-off switching tube just open switching tube until inductive current is reduced at 1 o'clock to this control mode again.The alternating current that critical discontinuous control method adopts is power frequency 50Hz civil power, Fig. 2 is the oscillogram that just half Monday, a metal-oxide-semiconductor handed over conducting to close, prerequisite is the inductive current that critical discontinuous control mode detected, the words of opening again in the time that electric current reduces to zero, can eliminate the loss of the caused main switch of diode reverse recovery, and the control method of this switching tube is simple in structure.Envelope ripple in Fig. 2 is envelope ripple, and inductive current I _lit is the actual current on the first inductance.Due in positive half period, second switch pipe is constantly in switching on and off state, as shown in the gate drive voltage of Fig. 2 bottom, second switch pipe with different frequencies in switching on and off alternating state, therefore inductive current IL is also among conversion, time and the zero point of arrival, time and reach envelope value.

Fig. 3 (a)～Fig. 3 (d) shows the current trend under different conditions.In circuit, also comprise a commutation capacitor C112.Inductance and electric capacity can both play the effect of boosting.By the circuit of Fig. 1, alternating current can be converted to the direct current boosting.And be all-wave conversion.

The technical scheme of control method is as follows:

Waveform digitization circuit: input waveform is carried out to digitlization;

Electric current loop testing circuit: detect the electric current flowing through on inductance;

Zero-crossing detection circuit: whether zero crossing of electric current on inductance is flow through in judgement;

Current comparison circuit: the PWM of envelope is carried out after A/D conversion, and the electric current on inductance compares, in the time that the electric current on inductance reaches envelope ripple, produces shutdown signal.

Control circuit: complicated programmable logic device (CPLD) judges the electric current on direction and the electric current of the input waveform of having changed through A/D, and controls four switching tubes.

Specific works process is as shown in Fig. 6 (a).

First with reference to figure 4, the schematic diagram that power factor circuit device zero crossing of the present invention detects as shown in Figure 4, inductance L 102 left sides correspond to A point, the right correspond to B point, according to saying the attribute that selects inductance, induction coil the right corresponds to A ', the left side corresponds to B ', as shown in Figure 4.Cross and be called with concrete enforcement: positive half cycle t10daotong, voltage comparator

In the time of positive half cycle, when metal-oxide-semiconductor T100 turn-offs, because the electric current in inductance L 102 can not suddenly change, therefore electric current can continue from left to right to flow, be UB > UA, UBA > 0, corresponding UB ' > UA ', UB ' A ' > 0, be under Fig. 4 upper negative just, electric current can not form loop, during due to positive half cycle, and U_IN～_ SIGN=L; / U_IN～_ SIGN=H; Be T10 conducting, T9 closes, D35, D34 conducting,

UA′＝0.65V；

UD35-A=0.65*2=1.3V；

UC'=(5-1.3)*1/11+1.3=1.63V；

$U_{E^{\′}}={5V}^{*}\left(\frac{1K}{1K+10K}\right)=0.455V$

The 4th pin voltage that is IC10A is 1.63V, and the 3rd pin voltage of IC10A is through dividing potential drop U _e'obtain 0.455V, the voltage of the 3rd pin is less than the voltage of the 4th pin, and therefore PFC_CUR1_ZERO is output as low level;

In the time that the electric current on L102 is reduced to zero, because the voltage in the parasitic capacitance of metal-oxide-semiconductor T100 inside is the active output voltage without bridge interleaving PFC circuit, be UB=UZK+, the current effective value of UA=input AC, now give L102 reverse charging, UB slowly reduces, when being reduced to less than UA time, voltage reversal, be UA>UB, UAB>0, corresponding UA'>UB', UA'B'>0, be the upper just lower negative of Fig. 4, due to UA' by diode D34 clamper at 0.65V, and UA'>UB', be less than 0.65V in the voltage of UB', like this current circuit from+5V through R48, R117, D33 arrives A' finally by crossing D34 again to B', T10 flows to GND.During in order to ensure zero crossing, PFC_CUR1_ZERO can be turned into high level (when low to high saltus step, there is zero current signal, just that metal-oxide-semiconductor T100 is again open-minded), on hardware, just must guarantee that the 4th pin voltage of IC10A will be lower than the voltage 0.455V of the 3rd pin, otherwise, if the voltage of the 4th pin is critical value 0.455V, UC'=0.455V can be obtained by Ohm's law:

$\frac{{5-U}_{C^{\′}}}{U_{C^{\′}}-U_{D^{\′}}}=\frac{1K}{100}$

Abbreviation can obtain UD '=0.0005V,

And UB '=UD '-0.650.0005-0.65=-0.6495V;

UA′B′＝UA′-UB′＝0.65-(-0.6495)＝1.2995V，

In like manner when negative half period, U_IN～_ SIGN=H ,/U_IN～_ SIGN=L, be T9 conducting, T10 closes, D33, D32 conducting, in the time that metal-oxide-semiconductor T101 turn-offs, because the electric current in inductance L 102 can not suddenly change, therefore electric current can continue to flow from right to left, be UA > UB, UAB > 0, corresponding UA ' > UB ', UA ' B ' > 0, be the upper just lower negative of Fig. 4, electric current is capable does not become loop.

When L102 current over-zero, when voltage reversal, be UB > UA, UBA > 0, corresponding UB ' > UA ', UB ' A ' > 0, be under Fig. 4 upper negative just, due to UB ' by diode D32 clamper at 0.65V, due to UB ' > UA ', institute is less than 0.65V in UA ', and current circuit again to B ' finally by mistake D32, T9 flow to GND through R48, R117, D35 to A ' from+5V like this.

Because what the present invention adopted is the shutoff of opening that CPLD controls zero current, Fig. 4 detects zero crossing, also needs to detect electric current.

As while being positive half cycle, when detect in Fig. 4 crossover point signal PFC_CUUR1_ZERO time, CPLD provides the signal of opening T100, in the time detecting that PFC_CUR1_HIGH in Fig. 5 (b) is low level, CPLD provides the signal of closing T100; Simultaneously in opening T100, start to calculate T100 and open to the time T of closing, when T/2 after T100 opens, CPLD provides the signal of opening T102, and the time span of opening with closing of T102 and the time of opening with closing of T100 are consistent.

As while being negative half period, when detect in Fig. 4 crossover point signal PFC_CUUR1_ZERO time, CPLD provides the signal of opening T101, in the time detecting that PFC_CUR_1_HIGH in Fig. 5 (b) is low level, CPLD provides the signal of closing T101; Simultaneously in opening T101, start to calculate T101 and open to the time T of closing, when T/2 after T101 opens, CPLD provides the signal of opening T103, and the time span of opening with closing of T103 and the time of opening with closing of T101 are consistent.

Complex programmable logic device (CPLD) converts the AC sine wave of input to digital quantity by A/D Acquisition Circuit, and this is processed to the PWM of the envelope ripple that forms input.

Concrete handling process is (as shown in Fig. 6 (b));

Digital quantity to the input waveform collecting judges its highest order, if 0 words are positive half cycle, if 1 words are negative half period.As while being positive half cycle, its digital quantity is consistent, if when negative half period, its digital quantity negate adds 1, namely negative half period waveform is turned into positive half cycle waveform.Due in the time that positive-negative half-cycle replaces, input waveform has the place at zero point and the zero point of approaching, in order to avoid this region, make input current waveform better follow input voltage waveform, therefore, by the waveform through halfwave rectifier, promote a benchmark, concrete operations are peak values that CPLD will calculate input waveform, half wave envelope is added to the peak value of 1/4, half wave envelope can be promoted, then be multiplied by the PI regulated value of a closed loop, be the IPEAK in Fig. 6 (b), and this envelope ripple is changed into PWM ripple.To be input to late-class circuit as Fig. 5 Ub).

Reach envelope ripple signal PFC_CUR_1_HIGH according to crossover point signal PFC_CUR1_ZERO and electric current and carry out opening and turn-offing of control switch pipe because that the present invention adopts is CPLD, Fig. 4 detects zero crossing, also need to detect electric current, the schematic diagram of concrete current detection circuit is Fig. 5 (a), is embodied as:

In the time of positive half cycle, PFC_U_IN～_ SIGN is low level, be that U_IN～_ SIGN is low level, / U_IN～_ SIGN is high level, T3, T4 close, T5 conducting, owing to there being the resistance (Fig. 5 (b) is that 4 20 Europe resistance are in parallel) in 5 Europe between PFC_CUR_1 and PFC_CUR_1_RTN.Electric current from 2 ends of TF1B to DH through T5 to PFC_CUR_1 through the resistance in 5 Europe again to D9, finally get back to 4 ends of TF1B, the electric current collecting is after 5 Europe resistance, become voltage and deliver to the 4th pin of comparator U10, above mentioned PWM ripple carries out entering into after elbow D conversion the 3rd pin of comparator U10, and both compare, when PFC_CUR_1_HIGH is during from height saltus step, just illustrate that measured value electric current has reached envelope signal, closes corresponding metal-oxide-semiconductor.

In like manner when negative half period, PFC_U_IN～_ SIGN is high level, i.e. U_IN～_ SIGN is high level, and/U_IN～_ SIGN is low level, T3, T4 conducting, and T5 closes.Electric current from TF1B 4 ends through D6 to T3 again to PFC_CUR_1, get back to 2 ends of TF1B through the resistance in 5 Europe and D10, the electric current collecting is through 5 Europe resistance, convert the 4th pin that voltage enters comparator U10 to, the above-mentioned PWM ripple of mentioning, after elbow D conversion, enters into comparator U10 the 3rd pin, both compare, in the time of PFC_CUR_1_HIGH saltus step from high to low, just illustrate that measured value electric current has reached the electric current of input requirements, closes metal-oxide-semiconductor.

Be mainly to carry out four metal-oxide-semiconductors in control chart 1 by software to open and turn-off, realize efficiently without bridge interleaving PFC, concrete block diagram as shown in Figure 6.

As shown in Figure 7, Vehicular charger power factor circuit device of the present invention can make the efficiency of PFC more than 97.5%, in the time that power output is 2.2KW, reaches 98%, the efficiency chart 7 of concrete visible charger.

Adopt numerically controlled zero voltage switching technology to carry out design current, convenient control, efficiency can reach 98%, the total humorous wave interference THD of input current (TotalHarrnonicDistortion) < 5% simultaneously.

Software control method that the present invention adopts and corresponding hardware circuit device can make the efficiency of Vehicular charger power factor circuit reach 98%.

Although embodiment of the present invention are open as above, but it is not restricted to listed utilization in specification and execution mode, it can be applied to various applicable the field of the invention completely, for those skilled in the art, can easily realize other modification, therefore do not deviating under the universal that claim and equivalency range limit, the present invention is not limited to specific details and illustrates here and the legend of describing.

Claims (8)

1. improve a circuit for Vehicular charger power factor, wherein, comprising:

Alternating current input power supplying, the one utmost point is connected to bridge rectifier, and another utmost point first inductor in parallel with two is connected with one end of the second inductor;

DC output end, its positive and negative polarities are connected with the two ends of bridge rectifier respectively, by bridge rectifier, the AC energy of alternating current input power supplying are converted to direct current energy and offer DC output end;

The other end of the first inductor is connected to respectively the positive pole of DC output end by the first switching tube, be connected to the negative pole of DC output end by second switch pipe; The other end of the second inductor is connected to respectively the positive pole of DC output end by the 3rd switching tube, be connected to the negative pole of DC output end by the 4th switching tube;

Wherein, when the voltage of alternating current input power supplying input is during in positive half cycle, second switch pipe and the operation of the 4th switching tube linked switch, and the first switching tube and the 3rd switching tube are in off-state; When the voltage of alternating current input power supplying input is during in negative half period, the first switching tube and the operation of the 3rd switching tube linked switch, and second switch pipe and the 4th switching tube are in off-state.

2. the circuit of raising Vehicular charger power factor as claimed in claim 1, wherein, described bridge rectifier comprises that anodal negative pole joins end to end, forms four diodes of loop, and a utmost point of described alternating current input power supplying is connected between the second diode and the 3rd diode and between the 4th diode and the first diode; Wherein, the positive pole of DC output end is connected between the first diode and the second diode; The negative pole of DC output end is connected between the 3rd diode and the 4th diode.

3. the circuit of raising Vehicular charger power factor as claimed in claim 2, wherein, between another utmost point of alternating current input power supplying and the first inductor and the link of the second inductor, be provided with galvanometer, and a utmost point of alternating current input power supplying is directly connected to the positive pole of DC output end by the 5th diode, wherein the side of the positive electrode of diode is positioned at alternating current input power supplying one side, and a utmost point of alternating current input power supplying is also directly connected to the negative pole of DC output end by the 6th diode, wherein the negative side of the 6th diode is positioned at alternating current input power supplying one side.

4. the circuit of the raising Vehicular charger power factor as described in claim 1 or 3, wherein, also comprise zero-crossing detection circuit, its influence value using induction coil corresponding to the first inductor is as input value, utilizes voltage comparator to detect whether zero crossing of the first inductor current.

5. the circuit of raising Vehicular charger power factor as claimed in claim 4, wherein, also comprises the first inductive current detection circuit, and it judges according to input voltage signal and power factor correction pulse current whether the first inductive current reaches envelope value.

6. utilize the circuit of the raising Vehicular charger power factor described in claim 1 to carry out the control method of power factor, wherein, comprise the following steps:

Step 1, the voltage waveform that alternating current input power supplying is inputted carry out digitlization, and the waveform that judges input AC electricity is positive half cycle or negative half period;

The electric current on the first inductance is flow through in step 2, detection;

If positive half cycle, when detect on the first inductance current zero-crossing point time, connect second switch pipe, be the first induction charging, when detecting that electric current disconnects second switch pipe while reaching envelope ripple, described the first inductive discharge, until current zero-crossing point again detected, again connect second switch pipe;

If negative half period, when detect on the first inductance current zero-crossing point time, connect the first switching tube, be the first induction charging, in the time that detection electric current reaches envelope ripple, disconnect the first switching tube, described the first inductive discharge, until current zero-crossing point again detected, again connect the first switching tube.

7. the control method of raising Vehicular charger power factor efficiency as claimed in claim 6, wherein, further comprising the steps of:

Calculate T cycle time that one of the first switching tube is switched to disconnection, control the 3rd switching tube T/2 time after the back to back next action cycle of the first switching tube starts and rise, follow the first switching tube and carry out on or off operation.

8. the control method of raising Vehicular charger power factor efficiency as claimed in claim 1, wherein, further comprising the steps of;

Calculate T cycle time that one of second switch pipe is switched to disconnection, control the 4th switching tube T/2 time after the back to back next action cycle of second switch pipe starts and rise, follow second switch pipe and carry out on or off operation.

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