CN100517926C - Partial active electrical source power factor correction circuit - Google Patents
Partial active electrical source power factor correction circuit Download PDFInfo
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- CN100517926C CN100517926C CNB2006100651313A CN200610065131A CN100517926C CN 100517926 C CN100517926 C CN 100517926C CN B2006100651313 A CNB2006100651313 A CN B2006100651313A CN 200610065131 A CN200610065131 A CN 200610065131A CN 100517926 C CN100517926 C CN 100517926C
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Abstract
The present invention provides a part active power factor correction circuit which has a branch circuit arranged between the anode of isolating diode and cathode of bridge rectification circuit. The correction circuit includes a second capacitor with one end connected with the anode of the isolating diode, the other end connected with the cathode of a second diode the anode of which is connected with the cathode of a third diode, the anode of the third diode is connected with one end of a third capacitor, and the other end of the third capacitor is connected with the cathode of dc output end of the bridge rectification circuit; the joint end of the connection between the anode of the second diode and the cathode of the third diode is connected to the other end of the ac input end of the bridge rectification circuit which has no connection with the inductor; a controlled switch is connected between the cathode of the second diode and the anode of the third diode; the controlled switch is controlled to close if the dc detected voltage of the bridge rectification circuit is lower than a critical voltage and is controlled to turn off if the dc detected voltage of the bridge rectification circuit is higher than a critical voltage.
Description
Technical field
The present invention relates to power technology, relate in particular to a kind of partial active electrical source power factor correction circuit.
Background technology
In electrical network, there is significant impact in various loads especially nonlinear load to grid supply quality.For example, the power supply of many electrical appliances need be converted to direct current with the alternating current of electrical network, produces pulsating current and include a large amount of current harmonics components in switching process.These current harmonics components blow back into electrical network, can cause the harmonic wave " pollution " to electrical network, cause harmonic voltage to fall when electric current flows through line impedance, and sinusoidal wave line voltage is distorted.In addition, the harmonic wave of generation also causes the power factor (PF) of power network current to descend, and increases the loss of power distribution system conductors and transformer; And increase the center line harmonic current, so that other power device on the electrical network is caused electromagnetic interference.Power factor reduces load capacity and the reliability that also influences whole power-supply system simultaneously.
At present, along with the development of converter technique, frequency control has become a kind of technological means of extensive use.Need power supply is carried out the conversion of AC-DC-AC in the frequency control, the various current harmonicss that said process can produce if do not take measures, will reduce grid power factor, and the actual power ability of electrical network is reduced; Simultaneously, also can produce electromagnetic interference, influence other power consumption equipment.Therefore, at present equipment such as various electrical equipment especially convertible frequency air-conditioner are carried out Active PFC and become inexorable trend.
At present, China executes " CCC authentication " to household appliances, and (the CCC authentication i.e. " China Compulsory Certification ", its English name is " China Compulsory Certification ") standard, reach the requirement of this standard, various domestic variable frequency equipment must carry out Active PFC.
The current harmonics of commercialization suppressed and the power factor calibration device is applied to can realize power factor correction, and make all EMC (electromagnetic compatibility) standards of satisfied " CCC authentication " of each harmonic electric current content in the domestic variable frequency equipment such as convertible frequency air-conditioner.Described EMC standard comprises EMI (electromagnetic interference) standard and EMS (Electronmagnetic Stamina) standard two partly.So-called electromagnetic interference is meant this electromagnetic noise that is unfavorable for other system that produces in the process of carrying out proper function of machine; So-called Electronmagnetic Stamina is meant the ability that machine is not influenced by periphery electromagnetic environment in the process of carrying out function.
By research in recent years, the existing multiple device that is used to improve the convertible frequency air-conditioner power factor and reduces the current harmonics component comprises:
1, passive power factor correcting circuit
Passive PFC exchanges the fundamental current of input and the phase difference of voltage by the compensation of components and parts such as inductance, electric capacity, diode, forces electric current consistent with voltage-phase, can reduce power supply mains by harmonics interference and electrical network are disturbed power supply.This power factor correction circuit can bring up to 0.7～0.8 with power factor, and current harmonic content drops to below 40%, is widely adopted in the electronic equipment of middle low capacity.Its major advantage be simple, cost is low, reliability is high, easy to maintenance, EMI is little, shortcoming is that the circuit volume is big and heavy, and power factor is not high, can only filter effect be arranged to a part of harmonic wave, and filter effect is subject to the influence that element or system parameters and mains frequency change; Under certain conditions may with system's generation resonance, accidents caused; When harmonic source increased, filter burden increased the weight of thereupon, so that may can not move etc. because of Harmonic overloading, and therefore, its calibration result also is not very good.
2, passive power factor corrective circuit
This mode can be described as active Active PFC mode again.Be divided into omnidistance passive power factor corrective and part passive power factor corrective again.
Fig. 1 illustrates a kind of omnidistance passive power factor corrective circuit of prior art, sort circuit inserts a DC/DC switch converters between rectifier and load, the applied current feedback technique, by PFC special logic chip controls, input electric current I i waveform was followed the tracks of in the whole electricity cycle exchanged input sinusoidal voltage waveform.This passive power factor corrective circuit can make Ii near sinusoidal, thereby makes the total harmonic distortion amount of input (THD) less than 5%, and power factor can bring up to 0.99 even higher.The problem of this power factor correction circuit is: the switching frequency of switch inside pipe very high (generally more than 20K), can produce sizable electromagnetic interference when therefore working, the interference voltage and the interference power of system are exceeded standard, generally multiple-stage filtering to be taked in order to suppress the interference that PFC self brought, the cost of frequency-changing control system certainly will be increased.In addition, because its operating frequency is very high, the high-frequency inductor that needs amorphous magnetic material to make magnetic core is mated, and this inductance price is very high, has further increased the cost of system, is unfavorable for market competition.
For solving the problem that omnidistance passive power factor corrective exists, using the active PFC of part also is a kind of selection preferably.Fig. 2 illustrates the circuit diagram of the active PFC of a kind of part under the prior art.The characteristics of this power factor correction circuit are in 180 degree electrical degrees power supply to be done an Active PFC, rather than constantly carry out the correction of power factor (PF) at whole power cycle.Therefore, the operating frequency of internal switch pipe has reduced, and electromagnetic interference is significantly reduced, and simultaneously, the effect of Active PFC is also better, and power factor (PF) can reach more than 95%.
As shown in Figure 2, in the circuit of the active PFC of this part, AC power U connects the bridge rectifier ac input end through inductance L.At the dc output end of bridge rectifier, be parallel with controlled switch SW with this bridge rectifier.The positive pole of bridge rectifier is connected the anode of diode D with the public terminal of described controlled switch, the negative electrode of this diode D connects load R.Described diode D role is a buffer action, can be referred to as isolating diode.Negative electrode one side at described diode D is parallel with storage capacitor C with described load.Described controlled switch SW has special-purpose control circuit to control its on off state.This control circuit is according to the on off state of supply voltage detected value control controlled switch SW.
See also Fig. 3, this illustrates the voltage waveform after the rectification in Fig. 2 circuit.U1 is the critical voltage that sets among the figure.This critical voltage is the separation whether power supply directly powers to load R.When supply voltage was higher than critical voltage U1, supply voltage was to load R power supply, when supply voltage is lower than this critical voltage U1, was actually by storage capacitor C and powered to the load.
In this circuit, when voltage was higher than U1 after the rectification, then controlled switch SW turn-offed.At this moment, Fig. 2 circuit can be reduced to equivalent electric circuit shown in Figure 4.As can be seen from Figure 4, inductance L and storage capacitor C form the LC loop in the circuit, can change the phase angle of voltage and electric current in the circuit, the raising power factor (PF).Saying from energy point of view, is exactly that inductance L discharges electric energy stored and is used to electric.Simultaneously, when the alternating voltage of power supply one side be lower than the rectifier bridge diode by voltage the time because electric current interrupts suddenly, can cause the rising of inductance L both sides voltage, make the diode conducting again in the rectifier bridge, thereby reduce the dead band part of the output voltage of rectifier bridge.
When voltage is reduced to when being lower than U1, described controlled switch SW is closed under the effect of ON-OFF control circuit, and by the obstruct of diode D, power supply one side forms independently loop, its equivalent circuit Fig. 5.As can be seen from Figure 5, this circuit is equivalent to power supply to the inductance L storage of electrical energy.Therefore, this moment, the electric energy of power supply U continued to obtain to utilize, and the inductance L electric energy stored is closed in switch SW and had no progeny, and will discharge to load R as previously mentioned.
Select under the situation of suitable electrical parameter, above-mentioned control switching time can make the each acquisition of inductance L near saturated charging, and when discharge, discharge most of electric energy, therefore, all electric energy all are fully used, be converted into active power, thereby power factor (PF) is significantly improved.This circuit can make power factor (PF) reach between the 0.95-0.96.
In a word, the active PFC of above-mentioned part can make controlled switch SW switch in 180 electrical degrees once simultaneously circuit power factor be significantly improved.The minimizing of controlled switch SW switch number of times, its direct benefit are to reduce electromagnetic interference, have avoided the electromagnetic interference problem of omnidistance active PFC mode.
But with regard to the improvement of power factor (PF), this PFC mode does not reach the effect that is close to 100% power factor (PF) of omnidistance active PFC, and therefore, its improvement can not be satisfactory.Producing under the situation of less electromagnetic interference equally, further improve power factor (PF) and become an important problem with above-mentioned pfc circuit.
Summary of the invention
At above-mentioned defective, the technical problem that the present invention solves is, a kind of part active PFC circuit is provided, and this kind circuit can further improve circuit power factor under the situation that produces less electromagnetic interference.
A kind of partial active electrical source power factor correction circuit provided by the invention, comprise an AC power, one end of this ac power output is by an end of the ac input end of inductance connection bridge rectifier, and the other end connects the other end of described bridge rectifier ac input end; The positive pole of the dc output end of described bridge rectifier connects the isolating diode anode, and the negative electrode of described isolating diode connects load one end, and the other end of load connects the negative pole of described bridge rectifier dc output end; Described load is parallel with first electric capacity, there is branch road between the anode of described isolating diode and the negative pole of described bridge rectifier, this branch road comprises second electric capacity that an end is connected with the anode of described isolating diode, the other end of this second electric capacity connects the negative electrode of second diode, the anode of this second diode connects the negative electrode of the 3rd diode, the anode of the 3rd diode connects an end of the 3rd electric capacity, and the other end of the 3rd electric capacity connects the negative pole of described bridge rectifier dc output end; The common ends that the anode of described second diode is connected with the negative electrode of the 3rd diode is connected the other end that is not connected with described inductance in the ac input end of described bridge rectifier; Between the anode of the negative electrode of described second diode and the 3rd diode, connect controlled switch; Controlled closure when this controlled switch is lower than a critical voltage at described bridge rectifier dc voltage, controlled shutdown when described bridge rectifier dc voltage is higher than this critical voltage.
Preferably, the shutoff of described controlled switch and closure are controlled by control unit; This control unit detects critical voltage, and testing result is controlled described controlled switch in view of the above.
Preferably, described control unit comprises zero crossing detecting unit, timing judging unit and switch control unit, described zero crossing detecting unit is used to detect the voltage over zero of described AC power, described timing judging unit is the timing datum mark according to detecting the described voltage over zero that obtains, and judges the relation of described bridge rectifier dc voltage and critical voltage with timing mode; Described switch control unit is controlled described controlled switch and is turn-offed with closed according to the judged result of described timing judging unit output.
Preferably, when detecting described supply voltage zero crossing, the time length that picks up counting, this time is to assert that then the dc voltage value begins to be higher than critical voltage; Continue another time span of timing, this time arrives, and assert that then the dc voltage value begins to be lower than described critical voltage.
Preferably, described time span obtains according to described AC supply voltage computation of Period.
Preferably, described timing judging unit and switch control unit are finished by single-chip microcomputer.
Preferably, described zero crossing detecting unit comprises: connect first current-limiting resistance of the end of oppisite phase of the end that is connected with inductance of described AC power and integrated operational amplifier, connect second current-limiting resistance of the positive terminal of the other end of described AC power and described integrated operational amplifier; Be connected with first clamp diode and second clamp diode between the positive terminal of described integrated operational amplifier and the end of oppisite phase; The anode of first clamp diode connects the positive terminal of described integrated operational amplifier, and negative electrode connects the end of oppisite phase of described integrated operational amplifier; Second clamp diode is then done opposite connection; Be connected feedback resistance and feedback capacity between the output of described integrated operational amplifier and the inverting input; The normal phase input end of described integrated operational amplifier connects the direct current reference voltage by resistance, and this normal phase input end is connected with the direct current seedbed by electric capacity simultaneously; The output of described integrated operational amplifier connects the mould/number conversion input port of single-chip microcomputer by input resistance; Described single-chip microcomputer mould/number conversion input port is connected to dc power anode by a diode forward, simultaneously also by the anti-phase direct current seedbed that is connected to of another diode.
Preferably, described controlled switch adopts igbt, and the grid of this igbt connects control voltage, and collector electrode connects the negative electrode of described first diode, and emitter connects the anode of described second diode; When control voltage is exported high and low level, control the igbt conducting respectively, end, realize controlled closure, the controlled shutdown of described controlled switch.
Preferably, between the emitter of the collector electrode of described igbt pipe and igbt, going back reverse parallel connection has the protection diode.
Preferably, the grid of described igbt connects described control voltage by diode, and the anode of described diode connects described control voltage, and negative electrode connects the grid of described igbt.
Pfc circuit provided by the invention, under the situation of the less advantage of the electromagnetic interference that has kept the active PFC of part, further improved the power factor (PF) of power supply, its reason is: under the prior art, because the effect that the voltage that does not exist above-mentioned voltage multiplying rectifier to produce raises, always there is a part of electric energy in the inductance L electric energy stored because magnitude of voltage is lower than storage capacitor voltage and can't discharges, and has limited the raising of power factor (PF).And in the technical scheme provided by the invention, after the controlled switch SW closure, power supply U and C1, C2 form voltage doubling rectifing circuit, and the C1 of series connection, C2 both sides obtain higher voltage.Have no progeny when controlled switch SW closes, because voltage is higher, therefore, will be easier to provides electric current to load R.Make electric energy obtain to make full use of, therefore power factor (PF) also further improves.
Description of drawings
Fig. 1 is a kind of omnidistance passive power factor corrective circuit of prior art;
Fig. 2 is the circuit diagram of a kind of partial PFC of prior art;
Fig. 3 is through the voltage waveform behind the bridge rectifier;
When Fig. 4 turn-offs for controlled switch, the equivalent electric circuit of circuit shown in Figure 2;
When Fig. 5 is the controlled switch closure, the equivalent electric circuit of circuit shown in Figure 2;
Fig. 6 is the circuit diagram of first embodiment of the invention;
Fig. 7 is that first embodiment of the invention diode D is in the equivalent circuit diagram when state;
Fig. 8 is in the first embodiment of the invention, when AC power live wire end is positive voltage, and the current direction schematic diagram of Fig. 7 circuit;
Fig. 9 is in the first embodiment of the invention, when the AC power zero line side is positive voltage, and the current direction schematic diagram of Fig. 7 circuit;
Figure 10 is the circuit theory diagrams of second embodiment of the invention;
Figure 11 is the circuit theory diagrams of the zero-crossing detection circuit of second embodiment of the invention.
Embodiment
Please, be the circuit diagram of first embodiment of the invention referring to Fig. 6.Because this embodiment further improves on the basis of the active PFC of part shown in Figure 2 in background technology of the present invention to obtain, therefore, among Fig. 6 with Fig. 2 in play same function element adopt identical mark.
As shown in Figure 6, as can be seen, this circuit is with the difference of the part active PFC circuit of prior art: its bridge rectifier current circuit dc output end is parallel with the branch road that capacitor C 1, capacitor C 2 and diode D1, diode D2 connect and form.Its concrete connected mode is: capacitor C 1 one ends connect the common ends of the anode of the positive pole of described rectification bridge output end and described diode D, and the other end connects the negative electrode of described diode D1; The anode of diode D1 connects the negative electrode of diode D2, and the anode of diode D2 connects an end of capacitor C 2, and the other end of capacitor C 2 then connects the negative pole of bridge rectifier dc output end.Simultaneously, the anode of described diode D1 also is connected with the output that AC power is not connected with inductance L with the interconnective common ends of the negative electrode of described diode D2; The anode tap of the cathode terminal of described diode D1 and described diode D2 is parallel with controlled switch SW.This controlled switch SW is in the state of turn-on and turn-off respectively under the control of control unit.
Please consult voltage oscillogram after the rectification of Fig. 3 simultaneously.In Fig. 3, when voltage was lower than voltage U 1 shown in the figure, the described controlled switch SW of Fig. 6 was in closure state.This moment, the voltage of diode D anode was lower, and negative electrode is in higher voltage owing to the capacitor C electric energy stored, therefore.Diode D is in by state.At this moment, the circuit of power supply one side is a voltage doubling rectifing circuit, and the equivalent circuit diagram of this side as shown in Figure 7.
For circuit shown in Figure 7, establishing the end that AC power is connected with inductance L is the AC power live wire, and the other end is the AC power zero line.
As shown in Figure 7, when AC power U was in positive half period, hot voltage was timing, in Fig. 7 circuit current direction as shown in Figure 8, at this moment, power supply is to capacitor C 1 charging.When AC power U was in negative half-cycle, zero line line voltage had been for just, in Fig. 7 circuit current direction as shown in Figure 9, power supply is to capacitor C 2 chargings.In the said process, the voltage swing that capacitor C 1, capacitor C 2 chargings obtain is identical, direction is identical.
Please continue referring to Fig. 3.When the voltage of Fig. 3 was higher than voltage U 1, described switch control unit control controlled switch SW disconnected.At this moment, capacitor C 1, capacitor C 2 make described diode D1, diode D2 forward conduction owing to accumulated positive voltage.Therefore, be in series connection between capacitor C 1 and the capacitor C 2, make the magnitude of voltage of this branch road be equivalent to the twice of each capacitance voltage value.Like this, the two ends of original rectifier output voltage have the voltage that a magnitude of voltage is the voltage twice that obtained of capacitor C 1 or capacitor C 2 each electric capacity charging, and this output voltage that just makes the rectifier two ends is than the most approaching dc output end voltage height of the prior art.This higher voltage can make diode D more be in the positively biased state, thereby makes supply voltage directly act on load, makes output power of power supply more become active power; Simultaneously, capacitor C 1 and capacitor C 2 are at controlled switch SW period of contact, and the power source charges that obtains also can be added in the load.The reason of above-mentioned two aspects is improved the power factor (PF) of circuit.
Compared with prior art, because the technical program has increased voltage doubling rectifing circuit, its effect is actually the waveform that improves the bridge rectifier output voltage, thereby make bridge rectifier voltage can surpass the magnitude of voltage of storage capacitor, thereby supply voltage is directly powered to the load, avoid the invalid electric power thus supplied of supply voltage.After adopting the technical program, select under the situation of suitable critical voltage U1 the power factor (PF) of circuit is brought up to more than 0.98.
Should illustrate simultaneously that described critical voltage can obtain explanation from theory, still actual is that selection can improve the desired value of power factor (PF) to greatest extent by test.
Above-mentioned first embodiment has stressed to illustrate the basic principle of technical solution of the present invention.Below second embodiment a kind of specific implementation circuit of the present invention is described.This embodiment is used to illustrate how described controlled switch SW realizes, and the device of controlling this controlled switch SW.
Figure 10 is the circuit theory diagrams of second embodiment of the invention.Adopt identical mark with the first embodiment components identical among this second embodiment.
As shown in figure 10, described controlled switch SW specifically adopts igbt (IGBT) to realize.
The grid of described igbt (IGBT) receives the control voltage that control unit K exports by a diode D4, and the high and low level of this control voltage makes this IGBT pipe conducting, shutoff respectively, thereby realizes the function of controlled switch.The anode of described diode D4 connects the output of described control unit, and negative electrode connects the grid of described IGBT pipe.The effect of this diode is that the leakage current that prevents described IGBT pipe flows to described control unit.
The collector electrode of this IGBT pipe connects the negative electrode of described diode D1, and emitter connects the anode of described diode D2.Simultaneously, between the emitter of the collector electrode of IGBT pipe and IGBT pipe, going back reverse parallel connection has protection diode D3, is used to prevent that reverse current from puncturing this IGBT pipe.
Described switch control unit K produces the high-low level signal in good time, controls the conducting and the shutoff of described IGBT pipe.
In the present embodiment, described switch control unit K comprises single-chip microcomputer and zero cross detection circuit.
Described zero cross detection circuit is used to detect the zero crossing of AC side voltage, when detecting alternating voltage zero-crossing, produces a zero crossing detection signal at every turn.Single-chip microcomputer receives and cover the zero crossing detection signal, and with described zero crossing detection signal as reference signal, adopt the method for time delay to control the conducting shutoff of described controlled switch SW.Because cycle of alternating voltage is fixed, therefore, adopt the method for zero passage detection, a timing benchmark can be provided, according to the cycle of alternating voltage, the time of the acquisition voltage reference voltage U1 by accurate timing.Specifically, can according to behind the computation of Period voltage zero-cross of alternating voltage through how long reaching described voltage U 1, and through how long magnitude of voltage turns back to voltage U 1 again.Suppose that through calculating the above-mentioned time is respectively n1 and n2 second, then with n1 second and n2 second as time of delay.After detecting voltage zero-cross at every turn, single-chip microcomputer is that starting point picks up counting with this zero crossing, reach n1 during second, then single-chip microcomputer is as the lead-out terminal output low level of control unit output, control described IGBT pipe and turn-off, when reaching n2 during second, then this lead-out terminal is exported high level, control the conducting of described IGBT pipe, thereby realize control described controlled switch SW (being the IGBT pipe in this example).Because AC power is after rectification, its generating positive and negative voltage all becomes forward voltage at the output of rectification circuit, but both waveform symmetry, therefore, described zero cross signal still is that negative half-cycle can be as reference signal to the positive half period of AC power, and described delay time n1 is consistent with n2 for positive and negative half period.
In above-mentioned control procedure, single-chip microcomputer plays the effect of timing and switch control.The above-mentioned effect of single-chip microcomputer also can adopt special-purpose timing unit and switch control unit to realize.
The control procedure of single-chip microcomputer as can be known, zero cross detection circuit is vital for the control of controlled switch SW.
Figure 11 illustrates a kind of zero-crossing detection circuit, and the principle of this zero cross detection circuit is described as follows.
This circuit comprises current limliting electricity group R111, current limliting electricity group R112, clamp diode D111, clamp diode D112, integrated operational amplifier S, feedback resistance R113, capacitor C 111, capacitor C 112, input resistance R114, diode D113, diode D114, resistance R 115.
The annexation of this circuit is as follows: current-limiting resistance R81 is connected between the end of oppisite phase of the common ends of AC power and described inductance L and integrated operational amplifier S, current-limiting resistance R112 connects the other end of AC power and the positive terminal of described integrated operational amplifier S, above-mentioned two resistance play metering function, make this zero cross detection circuit have big input resistance, the electric current of AC power has only less component to flow into zero cross detection circuit.
Be connected with clamp diode D111 and clamp diode D112 between the positive terminal of described integrated operational amplifier S and the end of oppisite phase.Wherein, the anode of clamp diode D111 connects the positive terminal of integrated operational amplifier S, and negative electrode connects the end of oppisite phase of integrated operational amplifier S; Clamp diode D112 then does opposite connection.The effect of above-mentioned clamp diode is to limit the voltage of described integrated operational amplifier S input, and this input voltage is remained on the suitable electronegative potential.
Be connected described resistance R 113 and described capacitor C 111 between the output of described integrated operational amplifier S and the inverting input, be used to make this integrated operational amplifier to work in the negative feedback state; The normal phase input end of integrated operational amplifier S is by resistance R 115 connection+2.5V reference voltages, this normal phase input end is connected with the direct current seedbed by capacitor C 112 simultaneously, the effect of this electric capacity is to make integrated operational amplifier S normal phase input end to exchange ground connection, avoids exchanging the influence of interference voltage.
The output of this integrated operational amplifier S connects mould/number (A/D) conversion input port I of single-chip microcomputer by resistance R 114.
Described Chip Microcomputer A/D conversion input port I is connected to DC power supply Vcc by diode D113 forward, simultaneously also by the anti-phase direct current seedbed that is connected to of diode D114.The effect of above-mentioned diode is to make the voltage of input Chip Microcomputer A/D conversion input port I to be in the suitable scope, and is neither too high low only.
The operation principle of above-mentioned zero-crossing detection circuit is: from AC power sampling alternating voltage, this voltage is limited in the lower scope by described clamp diode D111, D112, but still has the waveform of alternating current.Because the positive terminal of described integrated operational amplifier S connects described+2.5V reference voltage, thus the waveform of this alternating current with+the 2.5V reference voltage is the center, in the clamp voltage scope of described clamp diode, change.At the output of described operational amplifier S, obtain a voltage equally, and this voltage is that the center changes with the voltage of a positive potential through amplifying.This voltage outputs to the A/D conversion input port I of described single-chip microcomputer, is digital value in the single-chip microcomputer internal conversion.For this single-chip microcomputer, during alternating voltage zero-crossing, this digital value is a definite value.Therefore, when each single-chip microcomputer was read this definite value, then single-chip microcomputer as zero point, and began to carry out timing with it at this moment, and through described time n1 second or n2 during second, then the rectification unit output voltage reaches described critical voltage U1 and turns back to critical voltage U1 from this point.Control shutoff and the conducting of described controlled switch SW in view of the above.
The above only is a preferred implementation of the present invention; should be pointed out that for those skilled in the art, under the prerequisite that does not break away from the principle of the invention; can also make some improvements and modifications, these improvements and modifications also should be considered as protection scope of the present invention.
Claims (10)
1, a kind of partial active electrical source power factor correction circuit, comprise an AC power, one end of this ac power output is by an end of the ac input end of inductance connection bridge rectifier, and the other end connects the other end of described bridge rectifier ac input end; The positive pole of the dc output end of described bridge rectifier connects the isolating diode anode, and the negative electrode of described isolating diode connects load one end, and the other end of load connects the negative pole of described bridge rectifier dc output end; Described load is parallel with first electric capacity, it is characterized in that, there is branch road between the anode of described isolating diode and the negative pole of described bridge rectifier, this branch road comprises second electric capacity that an end is connected with the anode of described isolating diode, the other end of this second electric capacity connects the negative electrode of second diode, the anode of this second diode connects the negative electrode of the 3rd diode, the anode of the 3rd diode connects an end of the 3rd electric capacity, and the other end of the 3rd electric capacity connects the negative pole of described bridge rectifier dc output end; The common ends that the anode of described second diode is connected with the negative electrode of the 3rd diode is connected the other end that is not connected with described inductance in the ac input end of described bridge rectifier; Between the anode of the negative electrode of described second diode and the 3rd diode, connect controlled switch; Controlled closure when this controlled switch is lower than a critical voltage at described bridge rectifier dc voltage, controlled shutdown when described bridge rectifier dc voltage is higher than this critical voltage.
2, circuit according to claim 1 is characterized in that, the shutoff of described controlled switch and closure are controlled by control unit; This control unit detects critical voltage, and testing result is controlled described controlled switch in view of the above.
3, circuit according to claim 2, it is characterized in that, described control unit comprises zero crossing detecting unit, timing judging unit and switch control unit, described zero crossing detecting unit is used to detect the voltage over zero of described AC power, described timing judging unit is the timing datum mark according to detecting the described voltage over zero that obtains, and judges the relation of described bridge rectifier dc voltage and critical voltage with timing mode; Described switch control unit is controlled described controlled switch and is turn-offed with closed according to the judged result of described timing judging unit output.
4, circuit according to claim 3 is characterized in that, when detecting described supply voltage zero crossing, and the time length that picks up counting, this time is to assert that then the dc voltage value begins to be higher than critical voltage; Continue another time span of timing, this time arrives, and assert that then the dc voltage value begins to be lower than described critical voltage.
5, circuit according to claim 4 is characterized in that, described time span obtains according to described AC supply voltage computation of Period.
6, circuit according to claim 3 is characterized in that, described timing judging unit and switch control unit are finished by single-chip microcomputer.
7, circuit according to claim 3, it is characterized in that, described zero crossing detecting unit comprises: connect first current-limiting resistance of the end of oppisite phase of the end that is connected with inductance of described AC power and integrated operational amplifier, connect second current-limiting resistance of the positive terminal of the other end of described AC power and described integrated operational amplifier; Be connected with first clamp diode and second clamp diode between the positive terminal of described integrated operational amplifier and the end of oppisite phase; The anode of first clamp diode connects the positive terminal of described integrated operational amplifier, and negative electrode connects the end of oppisite phase of described integrated operational amplifier; Second clamp diode is then done opposite connection; Be connected feedback resistance and feedback capacity between the output of described integrated operational amplifier and the inverting input; The normal phase input end of described integrated operational amplifier connects the direct current reference voltage by resistance, and this normal phase input end is connected with the direct current seedbed by electric capacity simultaneously; The output of described integrated operational amplifier connects the mould/number conversion input port of single-chip microcomputer by input resistance; Described single-chip microcomputer mould/number conversion input port is connected to dc power anode by a diode forward, simultaneously also by the anti-phase direct current seedbed that is connected to of another diode.
8, circuit according to claim 1, it is characterized in that described controlled switch adopts igbt, the grid of this igbt connects control voltage, collector electrode connects the negative electrode of described first diode, and emitter connects the anode of described second diode; When control voltage is exported high and low level, control the igbt conducting respectively, end, realize controlled closure, the controlled shutdown of described controlled switch.
9, circuit according to claim 8 is characterized in that, between the emitter of the collector electrode of described igbt pipe and igbt, going back reverse parallel connection has the protection diode.
10, circuit according to claim 8, it is characterized in that, the grid of described igbt connects described control voltage by diode, and the anode of described diode connects described control voltage, and negative electrode connects the grid of described igbt.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2006100651313A CN100517926C (en) | 2006-03-17 | 2006-03-17 | Partial active electrical source power factor correction circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2006100651313A CN100517926C (en) | 2006-03-17 | 2006-03-17 | Partial active electrical source power factor correction circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN101039065A CN101039065A (en) | 2007-09-19 |
| CN100517926C true CN100517926C (en) | 2009-07-22 |
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| Application Number | Title | Priority Date | Filing Date |
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| CNB2006100651313A Active CN100517926C (en) | 2006-03-17 | 2006-03-17 | Partial active electrical source power factor correction circuit |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN102769335A (en) * | 2012-07-16 | 2012-11-07 | 张太平 | Dual-port input switch power supply |
| CN104124863B (en) * | 2013-04-28 | 2018-12-18 | 海尔集团技术研发中心 | The method and system of Active PFC based on radio energy transmission system |
| CN104348456B (en) * | 2013-07-26 | 2017-07-11 | 施耐德电气（澳大利亚）有限公司 | A kind of control method of electronic switch and electronic switch |
| CN106374736A (en) * | 2016-11-22 | 2017-02-01 | 郑州搜趣信息技术有限公司 | Sine wave voltage PFC circuit |
| CN113972827B (en) * | 2020-07-22 | 2024-04-26 | 广东美的制冷设备有限公司 | Totem pole PFC circuit, control method thereof, circuit board, air conditioner and storage medium |
| CN113300601A (en) * | 2021-06-30 | 2021-08-24 | 佛山市顺德区美的电子科技有限公司 | Household appliance, power supply circuit thereof, control method of power supply circuit and storage medium |
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