CN202818091U - Active power factor correction device - Google Patents

Active power factor correction device Download PDF

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Publication number
CN202818091U
CN202818091U CN2012204709121U CN201220470912U CN202818091U CN 202818091 U CN202818091 U CN 202818091U CN 2012204709121 U CN2012204709121 U CN 2012204709121U CN 201220470912 U CN201220470912 U CN 201220470912U CN 202818091 U CN202818091 U CN 202818091U
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chopper
voltage
processor
power factor
bus
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尹发展
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Hisense Shandong Air Conditioning Co Ltd
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Hisense Shandong Air Conditioning Co Ltd
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    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02BCLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B70/00Technologies for an efficient end-user side electric power management and consumption
    • Y02B70/10Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

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Abstract

The utility model discloses an active power factor correction device. The active power factor correction device comprises a chopper which is connected with both ends of the direct current side of a rectifier bridge, an inductor which is connected in series between the positive pole of the direct current side of the rectifier bridge and the chopper, a processor and a sampling circuit. An alternating current voltage sampling circuit is connected with an alternating current input power supply and collects the alternating current voltage of the alternating current input power supply and transmits the alternating current voltage to the processor. A direct current bus current sampling circuit is connected between the negative pole of the direct current side of the rectifier bridge and the chopper and collects the direct current bus current and transmits the direct current bus current to the processor. A direct current bus voltage sampling circuit collects the direct current bus voltage output by a chopped wave of the chopper and transmits the direct current bus voltage to the processor. The processor generates a pulse signal according to the received sampling signals to control the on and off of the chopper. The device can provide hardware support for different PFC control software. When power factor self-adaption control software is operated, self-adaption control can be realized on an alternating current power supply of a different frequency.

Description

A kind of Active Power Factor Correction device
Technical field
The utility model belongs to the control technique in power system field, specifically, relates to a kind of Active Power Factor Correction device be used to improving the Power Systems factor.
Background technology
In electric power system, the quantitative measurment of power quality has two key elements usually, i.e. power factor (Power Factor, PF) and total harmonic distortion amount (Total Harmonic Distortion, THD).Most of power electronic equipments all can cause in various degree interference effect to electric power system in application process, the power-supply device that particularly needs unsteady flow, such as rectifier, ups system, Variable Frequency Drives, thyristor system etc., electric current output after the unsteady flow is generally interrupted, of short duration high peak current pulse, and consequent circuit loss, total harmonic distortion and radiated interference all will obviously increase.
In order to improve the utilance of electric power system, need to be in power electronic equipment, increase power factor corrector in the supply line of connection electric power system, power factor correction PFC(Power Factor Correction) technology can effectively reduce harmonic content, improve power factor, reduce reactive power, high-efficiency pollution-free utilize the electrical network electric energy.
At present, along with the fast development of digital control technology and integrated IC, the PFC technology has had obvious progress on circuit topological structure and control technology.But, these PFC technology all are to study generation based on the basis of stabilized power source frequency and be applied, all be three parameter values of DC bus-bar voltage that gather unidirectional voltage, the dc bus current of exporting by the rectifier bridge rectification and export load in the pfc circuit design, transfer to processor to calculate the pulse signal that generates different duty, and then by driving the chopper break-make, to realize the correction to electrical source power factor.But, the frequency of different national employed AC power is not quite similar, the country that for example has adopts the AC power of 50Hz, the country that has then uses the AC power of 60Hz, therefore, the PFC technology that proposes based on this pfc circuit structure can not realize adaptive control to the AC power of different frequency, need to carry out to the type that exports to country variant the independent design of PFC technology, caused thus the R﹠D cycle long, production efficiency is hanged down inferior series of problems.
Summary of the invention
The purpose of this utility model is to provide a kind of Active Power Factor Correction device, selects sampling point position by rational in supply line, and suitable sample circuit is set, to realize that a cover pfc circuit is to the support of different PFC control strategies.
For solving the problems of the technologies described above, the utility model is achieved by the following technical solutions:
A kind of Active Power Factor Correction device comprises the chopper at the DC side two ends that are connected to rectifier bridge, the positive pole that is connected on the rectifier bridge DC side and the inductance between the chopper, is used for described chopper is carried out processor and the sample circuit that break-make is controlled; Described sample circuit comprises alternating voltage sampling circuit, dc bus current sample circuit and DC-bus voltage sampling circuit; Wherein, alternating voltage sampling circuit connects alternating current input power supplying, gathers the alternating voltage of alternating current input power supplying and transfers to described processor; Described dc bus current sample circuit is connected between the negative pole and chopper of rectifier bridge DC side, gathers dc bus current and transfers to described processor; The DC bus-bar voltage that described DC-bus voltage sampling circuit collection is exported by chopper copped wave, and transfer to described processor; Described processor exports the control utmost point of chopper to according to the sampled signal production burst signal that receives.
Preferably, in described alternating voltage sampling circuit, include an operational amplifier, the input of described operational amplifier respectively with the corresponding connection with zero line of live wire of alternating current input power supplying, the output of operational amplifier connects described processor.
A kind of preferred building mode as described dc bus current sample circuit, comprise sampling resistor and operational amplifier, described sampling resistor is connected between the negative pole and chopper of described rectifier bridge DC side, the input of operational amplifier is connected in parallel on the two ends of described sampling resistor, and the output of operational amplifier connects described processor.
In order to realize the overcurrent protection of supply line; in described Active Power Factor Correction device, also be provided with current foldback circuit; comprise comparator and with door; after described comparator gathers dc bus current and compares with setting threshold; output voltage signal to described and door; carry out and computing with the pulse signal of processor output, so by with door output pulse signal or zero level to the control utmost point of described chopper, realize the break-make control to chopper.
Further, the in-phase input end of described comparator connects the dividing potential drop node of the first resistance pressure-dividing network, and an end of described resistance pressure-dividing network connects DC power supply, and the other end is connected between the negative pole of described sampling resistor and rectifier bridge DC side; The inverting input of described comparator connects the dividing potential drop node of the second resistance pressure-dividing network, and described the second resistance pressure-dividing network is connected between described DC power supply and the ground.
Driving force for the pulse signal that improves processor output, to realize the reliable driving to chopper, preferably is connected one drive circuit at described output with door, amplify processing by described drive circuit pair and a pulse signal of exporting after, export the control utmost point of described chopper to.
Further again; for the mode of operation to overcurrent protection is selected; wherein one road IO mouth that preferably output of described comparator is connected processor; when the voltage that detects comparator output when processor is high level; according to the user selection protected mode, determine whether to continue output pulse signal.
A kind of preferred teaming method as described DC-bus voltage sampling circuit comprises a resistance pressure-dividing network, the direct voltage by described chopper copped wave output via described resistance pressure-dividing network dividing potential drop after, export described processor to by the dividing potential drop node.
Preferably, described chopper preferably adopts insulated gate bipolar transistor to carry out circuit design, and described transistorized grid receives described pulse signal, and collector electrode connects described inductance, grounded emitter, and connect the negative pole of rectifier bridge DC side by described dc bus current sample circuit.
Further, the collector electrode of described insulated gate bipolar transistor connects load by a power diode, and is connected with described DC-bus voltage sampling circuit.
Compared with prior art, advantage of the present utility model with good effect is: Active Power Factor Correction device of the present utility model can provide hardware supports for different PFC control software, when its operate power factor auto-adaptive controling software, can realize adaptive control in the AC power of different frequency, to reduce supply harmonic content, improve the utilance of power supply.This active PFC circuit is applied in the present convertible frequency air-conditioner product, and operate power factor auto-adaptive controling software, the PFC system that then forms thus is not only applicable to the national air conditioner based on the input of 50Hz AC power, equally also be applicable to the outlet air conditioner type based on the input of 60Hz AC power, primary development, the applicable purpose of design of multi-model have really been reached, greatly shorten the construction cycle of product, reduced R﹠D costs.
After reading by reference to the accompanying drawings the detailed description of the utility model execution mode, other characteristics of the present utility model and advantage will become clearer.
Description of drawings
Fig. 1 is the topological structure schematic diagram of the active PFC circuit that proposes of the utility model;
Fig. 2 is the control flow chart of a kind of embodiment of power factor self-adaptation control method;
Fig. 3 is the product process figure of a kind of embodiment of the generation method of the first voltage reference value Vs among Fig. 2;
Fig. 4 is the overall system architecture figure after Fig. 2 and Fig. 3 integrate;
Fig. 5 is the operation principle schematic diagram that the PWM module is compared in output among Fig. 2;
Fig. 6 is the testing current oscillogram of PFC alternating current input power supplying when not starting;
Fig. 7 is the testing current oscillogram of alternating current input power supplying after PFC starts;
Fig. 8 is the schematic block circuit diagram of a kind of embodiment of the active power factor calibration circuit that proposes of the utility model;
Fig. 9 is the circuit theory diagrams of a kind of embodiment of current protecting circuit among Fig. 8.
Embodiment
Below in conjunction with accompanying drawing embodiment of the present utility model is described in detail.
PFC is the english abbreviation of Power Factor Correction, i.e. power factor correction.Power factor refers to the relation between effective power and the total power consumption (apparent power), and namely effective power is divided by the ratio of total power consumption (apparent power).Basically, power factor can be weighed the degree that electric power is used effectively, and the value of power factor is larger, and the utilance that represents electric power is higher.In order to improve the utilance of electrical network electric energy, reduce the interference effect that power electronic equipment causes electrical network, in the power circuit design of most power electronic equipments, require to increase pfc circuit, to improve the conversion efficiency of power supply.
Consider that the supply frequency that the electrical network of country variant adopts is different, has plenty of 50Hz, has plenty of 60Hz, in order to make the pfc circuit that designs to be applicable to the alternating current input power supplying of different frequency, present embodiment has proposed a kind of Active Power Factor Correction device, can realize the adaptive control of active PFC on the different frequency AC power such as 50Hz, 60Hz.
The below at first is specifically described the basic hardware topological structure of active PFC circuit, and is described referring to Fig. 1.In active PFC circuit, mainly comprise processor, inductance L 1 and chopper.Wherein, the reactor of inductance L 1 for supporting that large electric current passes through plays the effect of energy storage in circuit.The power frequency AC AC that electrical network provides at first is input to rectifier bridge and is rectified into the Unidirectional direct-current power supply, then transfers to chopper via inductance L 1.Conducting or the shutoff under the control action of the pulse signal of processor output of described chopper, guarantee that input current is for sinusoidal wave under high input power factor, and carry out copped wave by the Unidirectional direct-current power supply to rectifier bridge rectification output and process, to generate level and smooth, constant DC bus-bar voltage Vdc, export the electric loading of using of rear class to.
In order to obtain higher power factor, need to carry out strict control to the turn-on and turn-off sequential of chopper, that is to say that needing processor to generate suitable pulse signal controls the accurate break-make of chopper, to generate and the synchronous simple alternating current input current of AC-input voltage, so that power factor is able to remarkable lifting.For a cover pfc circuit can be useful on the alternating current input power supplying of different frequency, the duty ratio of the pulse signal that need to generate processor is carried out self adaptation and is regulated, namely for the AC power AC frequency of inputting, automatically calculate the pwm pulse signal that generates different duty, export the control utmost point of chopper to, to realize the break-make control to chopper.
In order to realize the adaptive control of power factor, need the special control strategy of design to produce described pwm pulse signal, its Basic Design thinking is: because the DC bus-bar voltage Vdc by chopper output and the dc bus current Iac by rectifier bridge rectification output are two major parameters of active PFC control, in order to realize the adjusting to described two major parameters, the PFC technology of present embodiment adopts the double loop system of electric current loop and Voltage loop co-controlling, its software control block diagram mainly comprises voltage error compensator referring to shown in Figure 2, electric voltage feed forward compensator and current error compensator.Wherein, in the electric current loop system, the current reference value Iac-ref of current error compensator is that the product by the output voltage V comp three of the output voltage V pi of the rectification input voltage Vs that calculates alternating current input power supplying, voltage error compensator and electric voltage feed forward compensator obtains.Multiply by the rectification input voltage Vs synchronous with alternating current input power supplying, is for so that the reference value Iac-ref of current signal has the waveform identical with rectification input voltage Vs.Voltage error compensator is most important for the constant power output of maintenance, (described nominal value is the direct voltage desired value of setting in program to the DC bus-bar voltage Vdc of output and the nominal value of output voltage because it is responsible for, be target voltage Vdc-ref, described target voltage Vdc-ref operated by rotary motion is at 350V) depart from and compensate.Current inner loop makes the wave form varies that can follow as much as possible rectification input voltage Vs on its waveform, thereby obtains higher power factor by the flow through dc bus current Iac of inductance L 1 of adjusting.
Based on above-mentioned mentality of designing, need to be from active PFC hardware circuit design and the active PFC adaptive control system of PFC software control algorithm two aspect specific designs, to realize the adaptive control to the different frequency alternating current input power supplying.
The below at first from the PFC self-adaptation control method, sets forth the generative process of described pwm pulse signal, specifically comprises following major part:
(1) the PFC adaptive control algorithm of present embodiment need to gather three input signals: the alternating voltage Vac of alternating current input power supplying, the dc bus current Iac of rectifier bridge rectification output and the DC bus-bar voltage Vdc that exports after chopper copped wave conversion process.
The sample frequency of described three input signals can be designed to consistent with the AD sample frequency of processor.In the present embodiment, it is the english abbreviation of Digital Signal Controller that described processor preferably adopts digital signal controller DSC(DSC) carry out the calculating of PFC control algolithm, its AD sample frequency describes as an example of 16KHz example.
(2) for one of them reference value---the rectification input voltage Vs of the reference signal (being current reference value Iac-ref) of determining current inner loop, present embodiment adopts the voltage sinusoidal waveform that obtains alternating current input power supplying, from described voltage sinusoidal waveform, choose N sampled point, and the method that the sine value of each sampled point is taken absolute value, form described rectification input voltage Vs, as the first voltage reference value.
In order to obtain the voltage sinusoidal waveform of alternating current input power supplying, present embodiment preferably adopts the sine value look-up table, utilizes the alternating voltage peak of alternating current input power supplying, forms the sinusoidal waveform of alternating voltage.Namely obtain the voltage sinusoidal waveform of described alternating current input power supplying, from described voltage sinusoidal waveform, detect zero crossing, measure and calculate ac power frequency, calculate alternating voltage peak, form described rectification input voltage Vs by tabling look-up and calculating, as the first voltage reference value.
In order to make the PFC control method can automatically adapt to the alternating current input power supplying of different frequency, for example realize the adaptive control of active PFC on 50Hz and 60Hz AC power, present embodiment adopts following methods to generate described the first voltage reference value Vs:
Processor gathers the instantaneous value of alternating voltage Vac with fixing AD sample frequency (present embodiment describes as an example of 16KHz example), as the alternating voltage instantaneous value Vac(n that collects) be positive number, and Vac(n-1) when being negative, then can think Vac(n) be zero crossing, record the collection number (comprising zero crossing) between two zero crossings, as the sampled point number N in an alternating voltage cycle.
Owing in the process that drives the chopper turn-on and turn-off, can produce high-frequency interferencing signal, for the reliability that guarantees to detect, need to carry out fault-tolerant processing to described sampled point number N, namely by limiting the effective range of N, strengthen the reliability of algorithm.
In the present embodiment, the effective range of described N can adopt following methods to obtain:
The frequency range of setting alternating current input power supplying is H1 ~ H2, and then the periodic regime of alternating current input power supplying is t1 ~ t2, wherein, and t1=1/H2, t2=1/H1;
The effective range of calculating N is N1 ~ N2, and wherein, N1=t1/T, N2=t2/T, T are the AD sampling period of processor.
Take the PFC self-adaptation control method of compatible 50Hz and two kinds of supply frequencies of 60Hz as example describes, at this moment, the frequency range of alternating current input power supplying can be set between 45Hz ~ 65Hz, corresponding, the periodic regime of alternating current input power supplying is
Figure 178838DEST_PATH_IMAGE002
The AD sample frequency of considering processor is 16KHz, then the AD sampling period of processor
Figure 234738DEST_PATH_IMAGE004
The effective range that just can calculate thus N is
According to the effective range that calculates, N carries out fault-tolerant processing to the sampled point number, namely from a upper zero crossing to this zero crossing, if the record number of N in described effective range, then this zero crossing is effective zero crossing; Otherwise, this zero crossing is processed as invalid zero crossing, continue cumulative record and gather number, until next zero crossing.Then, repeat the deterministic process of described effective zero crossing, until be created on the sampled point number N in the effective range.
Be the alternating current input power supplying of 50Hz for frequency, the theoretical value of described sampled point number N
Figure 19340DEST_PATH_IMAGE008
Since the impact of interference signal, the possible deviation theory value 320 of the actual value of sampled point number N, but through after the fault-tolerant processing, error range can be very not large.
In like manner, be the alternating current input power supplying of 60Hz for frequency, the actual value of described sampled point number N should
Figure 901845DEST_PATH_IMAGE010
Near.
Then, take zero crossing as starting point, with one-period 0 ~ 2 π of alternating voltage Vac with 0 ~ 2 P-1Expression, wherein P by the data of processor process figure place (be once treatable data bits of processor, what can process simultaneously 8 bit data is exactly 8 machines, can process simultaneously 16 be exactly 16 machines), then the corresponding radian value of each numerical value is 2 pi/2s P-1, calculate the corresponding sine value of each described radian value, form thus a sine value table.
Describe as 16 machines as example take described processor, then the wave period length of whole alternating voltage Vac represents with 2^15=32768, one-period 0 ~ 2 π that is alternating voltage Vac represents with 0 ~ 32768, the radian value that then each numerical value is corresponding is 2 π/32768, can calculate accordingly the corresponding sine value of each radian value, so just form a sine value table.
The setting step-length of tabling look-up is 2 P-1/ N, for 16 machines, the step-length of namely tabling look-up is 32768/N, and the result of being divided by is rounded processing, according to the step-length of tabling look-up described sine value table is tabled look-up, and obtains N sine value.
The alternating voltage peak of the alternating current input power supplying that collects and the resulting sine value of tabling look-up are each time multiplied each other, calculate the alternating voltage instantaneous value of each sampled point in N the sampling, these alternating voltage instantaneous values couple together and have just formed sine curve, referring to shown in Figure 3.Be not difficult to find out: if the frequency of alternating current input power supplying is 50Hz, the sine curve of the alternating voltage that computation of table lookup obtains is exactly the sine value curve of 50Hz; If the frequency of alternating current input power supplying is 60Hz, the sine curve of the alternating voltage that obtains of tabling look-up is exactly the sine value curve of 60Hz.The figure place of processor is higher, and the sine value curve that obtains is just more accurate.
Alternating voltage instantaneous value to each sampled point takes absolute value, and has so just formed the rectification input voltage Vs among Fig. 2, i.e. described the first voltage reference value.
(3) for the another one reference value Vpi of the reference signal (being current reference value Iac-ref) of determining current inner loop, present embodiment adopts voltage error compensator to calculate output.
As shown in Figure 2, with the DC bus-bar voltage Vdc that collects and the target voltage Vdc-ref substitution voltage error compensator of setting, compare by the target voltage Vdc-ref with DC bus-bar voltage Vdc and setting, and after carrying out the compensation of voltage error processing, generating reference value Vpi is designated as second voltage reference value Vpi.
In the present embodiment, voltage error compensator has consisted of the external control Voltage loop, and effect is the target voltage Vdc-ref that control DC bus-bar voltage Vdc reaches setting.So no matter the unexpected alternating voltage that changes or input occurs suddenly variation occurs in load, because voltage error compensator has higher response speed, so adjustment DC bus-bar voltage Vdc that can both be very fast arrives the target voltage Vdc-ref that sets.
In the present embodiment, described voltage error compensator preferably adopts traditional PID control strategy, with the difference VEER substitution PID computing formula of target voltage Vdc-ref and DC bus-bar voltage Vdc, calculates and generates second voltage reference value Vpi.
Second voltage reference value Vpi by voltage error compensator output as control signal, is participated in the determining of current reference value Iac-ref of current inner loop.
Because the input signal of outer voltage is target voltage Vdc-ref and the actual DC bus-bar voltage Vdc that detects, voltage error compensator is for generation of control output, no matter how the alternating voltage Vac of load current and input changes, it is constant that DC bus-bar voltage Vdc will keep, and namely equals target voltage Vdc-ref.Utilize voltage error compensator that the DC bus-bar voltage Vdc that exports is controlled, when the alternating voltage Vac of input increased, the product of Vs and Vpi increased, thus so that current reference value Iac-ref increase.When this current reference value Iac-ref divided by alternating voltage mean value square after (being the output valve of electric voltage feed forward compensator), will obtain the corresponding current reference value Iac-ref that reduces in proportion.The result is, corresponding the reducing of ratio that dc bus current Iac increases according to alternating voltage Vac, thus the maintenance power output is steady state value.
(4) for the 3rd reference value Vcomp of the reference signal (being current reference value Iac-ref) of determining current inner loop, present embodiment adopts the electric voltage feed forward compensator to calculate output.
As shown in Figure 2, in an ac cycle, the alternating voltage Vac of alternating current input power supplying is carried out N sampling, after the magnitude of voltage of each sampled point is taken absolute value, calculate the mean value of N magnitude of voltage, namely
Figure 316646DEST_PATH_IMAGE012
Described mean value is carried out getting inverse behind the square operation, namely , form thus tertiary voltage reference value Vcomp.
The value of described N is identical with sampled point number in the process (2); Described electric voltage feed forward compensator is at tertiary voltage reference value Vcomp of each alternating voltage computation of Period output of alternating current input power supplying.
The purpose of introducing the electric voltage feed forward compensator is exactly to keep constant by the definite power output of load, no matter and how the line voltage of alternating current input power supplying changes.Specifically, if alternating voltage Vac reduces, reduce in proportion for the product Vs*Vpi that determines current reference value Iac-ref is also corresponding.Yet, when this current reference value Iac-ref divided by alternating voltage mean value square after, will obtain the corresponding current reference value Iac-ref that scales up.The result is, the corresponding increase of ratio that dc bus current Iac reduces according to alternating voltage Vac, thus keep constant power output.
(5) will calculate three voltage reference value Vs, Vpi, Vcomp generating and multiply each other after, determine the reference signal of current inner loop, i.e. current reference value Iac-ref.
In the present embodiment, because bearing power is in different size, after preferably described three voltage reference value Vs, Vpi, Vcomp being multiplied each other, multiply by again a COEFFICIENT K M, obtaining the sine value curve corresponding with the frequency of alternating current input power supplying, the waveform of described sine value curve is as the waveform of the first voltage reference value Vs, is about to the negative half period waveform and is inverted to formed waveform behind the positive half cycle, as shown in Figure 2, with this current reference value Iac-ref as the current error compensator.
Here, the voltage range of the value of COEFFICIENT K M and hardware circuit parameter, bearing power and alternating current input power supplying has relation, and KM generally mates in the 2-10 scope.
(6) for the duty ratio of pwm pulse signal, present embodiment adopts the current error compensator to calculate output.
As shown in Figure 2, the current reference value Iac-ref that generates and the dc bus current Iac substitution current error compensator that collects will be calculated, compare by the dc bus current Iac with current reference value Iac-ref and rectifier bridge rectification output, and after carrying out the current error compensation deals, output is used for the result of calculation Ipi of the duty ratio of definite pwm pulse signal.
In the present embodiment, the current error compensator has consisted of the internal control electric current loop, and the input of electric current loop is the dc bus current Iac that current reference value Iac-ref and actual samples obtain, and can make dc bus current Iac can follow reference current Iac-ref and change.
In the present embodiment, described current error compensator preferably adopts traditional PID control strategy, with the difference IEER substitution PID computing formula of current reference value Iac-ref and dc bus current Iac, calculates and generates dutyfactor value Ipi.
Compare with Voltage loop, electric current loop should have faster response speed, and carrier frequency can be set to 16 KHz.The dutyfactor value Ipi that the current error compensator is produced transfers to relatively PWM module of output, after quantizing, generates the pwm pulse signal that is used for driving the chopper break-make.
Fig. 4 is the software and hardware integration system block architecture diagram of described PFC self-adaptation control method.
(7) utilize the dutyfactor value Ipi of current error compensator output to generate the process of pwm pulse signal referring to shown in Figure 5, namely utilize the internal hardware resources of processor---carrier frequency register, duty cycle register and comparator, by the value of internal register is set, allowing it be operated in output compares under the PWM pattern, generate thus the pwm pulse signal that is used for driving the chopper break-make, detailed process is:
A, the carrier frequency of pwm pulse signal is set by the carrier frequency register.
In the present embodiment, the carrier frequency F1 of described pwm pulse signal is arranged to the AD sample frequency of processor, according to the pre-frequency division value P1 of comparator operating frequency in the dominant frequency FCY of processor and the processor, calculates the value OC1TMR of carrier frequency register, namely
Figure 759446DEST_PATH_IMAGE016
With the carrier frequency F1=16KHz of pwm pulse signal, the dominant frequency FCY=80MHz of processor, the pre-frequency division of comparator operating frequency are that 1:1(is P1=1) for example describes, then
Figure 180063DEST_PATH_IMAGE018
Calculate: OC1TMR=4999.
B, the result of calculation Ipi that the current error compensator is exported write duty cycle register, as the value OC1R of duty cycle register.
C, comparator each clock cycle of its work (namely ) accumulated counts once, and the value OC1R of count value and duty cycle register once compared, if count value equate with the value OC1R of duty cycle register, then produce coupling and interrupt the OC1IF among waveform such as Fig. 5.
D, described processor are before coupling is interrupted the OC1IF generation, by the control utmost point (for example grid of IGBT) the output high level signal of its OC1 pin to chopper, the conducting of control chopper; Counter-rotating becomes low level when coupling interrupts producing, the control chopper turn-offs, until the count value of comparator is when equaling OC1TMR, for example count value arrives at 4999 o'clock, namely arrive a carrier cycle of pwm pulse signal, the level state of the OC1 pin of processor is reset to high level, and to the count value zero clearing of comparator.
Repeat process b ~ d, namely form needed pwm pulse signal.
Formed pwm pulse signal is exported to the control utmost point of chopper, the grid of insulated gate bipolar transistor IGBT for example, by control transistor IGBT break-make, with copped wave stable output, level and smooth DC bus-bar voltage Vdc, transfer to the rear class electric loading, for load provides stable direct-current working volts.
The execution of above-mentioned PFC control method need to design special active PFC circuit hardware supports is provided, and present embodiment has proposed hardware circuit framework as shown in Figure 8 for this reason, comprises rectifier bridge DZ1-DZ4, inductance L 1, chopper, processor DSC and sample circuit.Wherein, described chopper preferably adopts an insulated gate bipolar transistor IGBT realization to the copped wave conversion of the Unidirectional direct-current power supply of rectifier bridge DZ1-DZ4 rectification output.
Specifically, the AC connection alternating current input power supplying AC with described rectifier bridge DZ1-DZ4 is rectified into the Unidirectional direct-current power supply with the AC power of inputting, by the DC side output of rectifier bridge DZ1-DZ4.Inductance L 1 is connected between the collector electrode of the positive pole of rectifier bridge DZ1-DZ4 DC side and IGBT, the grounded emitter of IGBT, and connect the negative pole of rectifier bridge DZ1-DZ4 DC side by sampling resistor R0.Described sampling resistor R0 and operational amplifier G2 consist of the dc bus current sample circuit, and the dc bus current Iac that rectifier bridge DZ1-DZ4 rectification is exported samples, and exports described processor DSC to.Specifically, two inputs of described operational amplifier G2 can be connected in parallel on the two ends of described sampling resistor R0, utilize sampling resistor R0 that dc bus current is converted to sampled voltage, and after amplifying processing by operational amplifier G1, export the ADC interface of processor DSC to, carry out analog-to-digital conversion process with the generating digital amount, as the dc bus current Iac of current inner loop, participate in the calculating of current error compensator.The collector electrode of IGBT is connected the rear class electric loading by power diode D1, to steady, the constant DC bus-bar voltage of load output.In order to realize the sample detecting to described DC bus-bar voltage, present embodiment preferably adopts two divider resistance R1, R2 series connection to consist of DC-bus voltage sampling circuit, be connected between the negative electrode and ground of power diode D1, after the DC bus-bar voltage of IGBT copped wave output was carried out dividing potential drop, output sampled voltage Vdc was to processor DSC.Described processor DSC utilizes its inner analog to digital converter ADC that the sampled voltage Vdc that receives is carried out analog-to-digital conversion, and the generating digital amount as the DC bus-bar voltage Vdc of outer voltage, participates in the calculating of voltage error compensator.In addition, further one road filter capacitor C1 in parallel between the negative electrode of described power diode D1 and ground, as shown in Figure 8, with the interference signal in the filtering supply line, so that export to the DC bus-bar voltage of electric loading more stable.
For the required alternating voltage Vac of PFC adaptive control algorithm, present embodiment preferably adopts operational amplifier G1 to consist of alternating voltage sampling circuit, be connected between alternating current input power supplying AC and the processor DSC, realization is to the sample detecting of the alternating voltage of the AC of alternating current input power supplying.Specifically, can be with the corresponding connection with zero line of live wire of two inputs with the AC of alternating current input power supplying of described operational amplifier G1, after gathering alternating voltage and dwindling conversion, export the ADC interface of processor DSC to, after converting digital quantity to, the generation that participates in the first voltage reference value Vs and tertiary voltage reference value Vcomp is calculated.
Described processor DSC is by gathering sampled value Vac, Iac, the Vdc of alternating voltage sampling circuit, dc bus current sample circuit and DC-bus voltage sampling circuit output, the above-mentioned PFC adaptive control algorithm of substitution, can calculate the generation pwm pulse signal, export the control utmost point of chopper to, for example the grid of IGBT by the break-make sequential of control IGBT, is generating steady DC bus-bar voltage, when satisfying the load need for electricity, obtain higher power factor.
Certainly, described alternating voltage sampling circuit, dc bus current sample circuit and DC-bus voltage sampling circuit also can adopt other circuits built modes, and present embodiment is not limited in above giving an example.
In addition, in order to realize the overcurrent protection to supply line, present embodiment also is designed with current foldback circuit in described active PFC circuit, referring to shown in Figure 8, mainly comprise comparator and with door.Wherein, described comparator gathers dc bus current and compares with setting threshold REF, in the time of in dc bus current is in safe range, by comparator output high level to wherein one road input of door, described other one road input with door is connected processor DSC, and the pwm pulse signal of receiving processor output is because the voltage of comparator output is high level, therefore pwm pulse signal can by transferring to the grid of IGBT with door, be realized the break-make control to IGBT.And when dc bus current is higher than setting threshold; enter the overcurrent protection state; the extremely described and door by the comparator output low level; the output of blocking-up pwm pulse signal; at this moment, be low level by the level with door output, control IGBT turn-offs; dc bus current is reduced, reach the purpose of overcurrent protection.
Fig. 9 is the physical circuit schematic diagram of described current foldback circuit, and wherein, resistance R 204, R207 be in parallel to consist of described sampling resistor R0, is connected between the negative pole of the emitter of IGBT and rectifier bridge DZ1-DZ4 DC side.With the in-phase input end of comparator U202+the be connected to dividing potential drop Nodes of the first resistance pressure-dividing network that is consisted of by resistance R 220, R222 and R229, specifically, the in-phase input end of described comparator U202+one side connects DC power supply+5V by divider resistance R229, the parallel branch that forms by divider resistance R220, R222 on the other hand is connected in the supply line between the negative pole of sampling resistor R0 and rectifier bridge DZ1-DZ4 DC side, i.e. the c point.With the inverting input of comparator U202-be connected to the dividing potential drop Nodes of the second resistance pressure-dividing network that is consisted of by resistance R 230, R232, and described the second resistance pressure-dividing network is connected between DC power supply+5V and the ground.The resistance value of regulating resistance R230, R232 is to generate suitable setting threshold REF.As a kind of preferred design of present embodiment, can select resistance identical two resistance R 230, R232 to consist of described the second resistance pressure-dividing network, namely setting threshold REF is 2.5V.
Because the grounded emitter of IGBT, when active PFC circuit was worked, dc bus current Iac flowed to the negative pole of rectifier bridge DZ1-DZ4 DC side via sampling resistor R0 by the emitter of IGBT.Because sampling resistor R0 forms pressure drop, electric current is larger, and the current potential that c order in the circuit is just lower, and is negative value, thus so that the in-phase input end of comparator+partial pressure potential lower.The in-phase input end of comparator U202+partial pressure potential when being higher than setting threshold 2.5V, the output of comparator U202 is in high-impedance state, and under the effect of the pull-up circuit that DC power supply+3.3V and current-limiting resistance R308 consist of, the output high level to the input B of door U203.Described input A with door U203 is connected processor DSC by resistance R 231, the pwm pulse signal of receiving processor DSC output, at this moment, synchronous with output and the described pwm pulse signal of door U203, after transferring to the lifting that drive circuit U200 carries out load capacity, export the grid of IGBT to, realize the break-make control to IGBT.When dc bus current Iac continue to increase, cause the in-phase input end of comparator U202+partial pressure potential when being lower than setting threshold 2.5V, the output potential of comparator U202 is reverse, becomes low level.At this moment, no matter which kind of state the pwm pulse signal of processor DSC output be, by all will forcing output low level with door U203, and then shutoff IGBT, enter the overcurrent protection state.
Have no progeny in the IGBT pass; dc bus current Iac begins to reduce; might be reduced to very soon in the safe range; cause active PFC circuit to restart at short notice; again after startup soon because the again increase of electric current I ac and again enter guard mode, and described of short duration protection process repeatedly.For the selection that realizes of short duration protection and two kinds of patterns of long-term protection is carried out; present embodiment preferably is connected to the output of comparator U202 on the IO mouth of processor DSC; when processor DSC is low level at the output voltage that detects comparator U202; (of short duration protection or long-term protection) determines whether to continue the output pwm pulse signal according to the previously selected protected mode of user; namely when of short duration protected mode, continue the output pwm pulse signal; when long-term protected mode, stop to export pwm pulse signal, to satisfy the different operating requirement of active PFC circuit.
With above-mentioned Active Power Factor Correction application of installation in the design of the power circuit of power electronic equipment, for example be applied in the transducer air conditioning of 5KW, contrast before the described active PFC circuit startup and the current waveform of the alternating current input power supplying after starting, can clearly find out: when active PFC circuit does not start, the testing current waveform of alternating current input power supplying as shown in Figure 6, input current is interrupted, of short duration high peak current pulse, and this impact to electrical network is very large, and power factor only has 80%; And after active PFC circuit starts, the testing current waveform of alternating current input power supplying as shown in Figure 7, input current waveform is level and smooth, current phase is followed voltage-phase, power factor reaches more than 99%, and can satisfy the adaptive control to 50Hz and two kinds of frequency alternating current input power supplyings of 60Hz fully.
Certainly; the above only is a kind of preferred implementation of the present utility model; should be noted that; for those skilled in the art; under the prerequisite that does not break away from the utility model principle; can also make some improvements and modifications, these improvements and modifications also should be considered as protection range of the present utility model.

Claims (10)

1. an Active Power Factor Correction device is characterized in that: comprise the chopper at the DC side two ends that are connected to rectifier bridge, the positive pole that is connected on the rectifier bridge DC side and the inductance between the chopper, be used for described chopper is carried out processor and the sample circuit that break-make is controlled; Described sample circuit comprises alternating voltage sampling circuit, dc bus current sample circuit and DC-bus voltage sampling circuit; Wherein, alternating voltage sampling circuit connects alternating current input power supplying, gathers the alternating voltage of alternating current input power supplying and transfers to described processor; Described dc bus current sample circuit is connected between the negative pole and chopper of rectifier bridge DC side, gathers dc bus current and transfers to described processor; The DC bus-bar voltage that described DC-bus voltage sampling circuit collection is exported by chopper copped wave, and transfer to described processor; Described processor exports the control utmost point of chopper to according to the sampled signal production burst signal that receives.
2. Active Power Factor Correction device according to claim 1, it is characterized in that: in described alternating voltage sampling circuit, include an operational amplifier, the input of described operational amplifier connects live wire and the zero line of alternating current input power supplying, and the output of operational amplifier connects described processor.
3. Active Power Factor Correction device according to claim 1, it is characterized in that: in described dc bus current sample circuit, comprise sampling resistor and operational amplifier, described sampling resistor is connected between the negative pole and chopper of described rectifier bridge DC side, the input of operational amplifier is connected in parallel on the two ends of described sampling resistor, and the output of operational amplifier connects described processor.
4. Active Power Factor Correction device according to claim 3, it is characterized in that: in described Active Power Factor Correction device, also include comparator and with door, after described comparator gathers dc bus current and compares with setting threshold, output voltage signal to described and door, carry out and computing with the pulse signal of processor output, so by with door output pulse signal or the zero level control utmost point to described chopper.
5. Active Power Factor Correction device according to claim 4, it is characterized in that: the in-phase input end of described comparator connects the dividing potential drop node of the first resistance pressure-dividing network, one end of described resistance pressure-dividing network connects DC power supply, and the other end is connected between the negative pole of described sampling resistor and rectifier bridge DC side; The inverting input of described comparator connects the dividing potential drop node of the second resistance pressure-dividing network, and described the second resistance pressure-dividing network is connected between described DC power supply and the ground.
6. Active Power Factor Correction device according to claim 4, it is characterized in that: described output with door is connected one drive circuit, after a pulse signal by described drive circuit pair and door output amplifies processing, export the control utmost point of described chopper to.
7. Active Power Factor Correction device according to claim 4 is characterized in that: wherein one road IO mouth of the output connection processor of described comparator.
8. Active Power Factor Correction device according to claim 1, it is characterized in that: in described DC-bus voltage sampling circuit, include a resistance pressure-dividing network, direct voltage by described chopper copped wave output via described resistance pressure-dividing network dividing potential drop after, export described processor to by the dividing potential drop node.
9. each described Active Power Factor Correction device in 8 according to claim 1, it is characterized in that: described chopper is insulated gate bipolar transistor, described transistorized grid receives described pulse signal, collector electrode connects described inductance, grounded emitter, and connect the negative pole of rectifier bridge DC side by described dc bus current sample circuit.
10. Active Power Factor Correction device according to claim 9 is characterized in that: the collector electrode of described insulated gate bipolar transistor connects load by a power diode, and is connected with described DC-bus voltage sampling circuit.
CN2012204709121U 2012-09-17 2012-09-17 Active power factor correction device Expired - Lifetime CN202818091U (en)

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CN107623434A (en) * 2017-09-06 2018-01-23 湖北工业大学 Window pwm control circuit for five level power factor adjusters
CN109442669A (en) * 2018-11-12 2019-03-08 奥克斯空调股份有限公司 A kind of air conditioning control method, device and air conditioner
CN109861519A (en) * 2019-01-23 2019-06-07 广东美的制冷设备有限公司 Power circuit and air conditioner
CN110649801A (en) * 2019-08-13 2020-01-03 深圳市航嘉聚源科技股份有限公司 Bus voltage sampling method, PFC control circuit and power conversion circuit
CN111277198A (en) * 2020-02-25 2020-06-12 佛山市钒音科技有限公司 Control device for driving variable frequency motor and household appliance
CN112271919A (en) * 2020-11-06 2021-01-26 儒竞艾默生环境优化技术(上海)有限公司 Current compensation method, medium and current compensation device based on power factor correction
CN112996186A (en) * 2019-12-18 2021-06-18 安徽展晖电子科技有限公司 Pulse-controlled circuit unit, drive circuit, integrated circuit and lighting device
CN113315391A (en) * 2021-04-29 2021-08-27 武汉华海通用电气有限公司 Digital PFC circuit
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CN107623434B (en) * 2017-09-06 2020-10-02 湖北工业大学 Window PWM control circuit for five-level power factor corrector
CN107623434A (en) * 2017-09-06 2018-01-23 湖北工业大学 Window pwm control circuit for five level power factor adjusters
CN109442669A (en) * 2018-11-12 2019-03-08 奥克斯空调股份有限公司 A kind of air conditioning control method, device and air conditioner
CN109442669B (en) * 2018-11-12 2020-11-24 奥克斯空调股份有限公司 Air conditioner control method and device and air conditioner
CN109861519A (en) * 2019-01-23 2019-06-07 广东美的制冷设备有限公司 Power circuit and air conditioner
CN110649801A (en) * 2019-08-13 2020-01-03 深圳市航嘉聚源科技股份有限公司 Bus voltage sampling method, PFC control circuit and power conversion circuit
CN110649801B (en) * 2019-08-13 2021-11-26 深圳市航嘉聚源科技股份有限公司 Bus voltage sampling method, PFC control circuit and power conversion circuit
CN112996186A (en) * 2019-12-18 2021-06-18 安徽展晖电子科技有限公司 Pulse-controlled circuit unit, drive circuit, integrated circuit and lighting device
CN111277198A (en) * 2020-02-25 2020-06-12 佛山市钒音科技有限公司 Control device for driving variable frequency motor and household appliance
CN111277198B (en) * 2020-02-25 2023-06-06 广东三华钒音科技有限公司 Control device for variable frequency motor drive and household appliance
CN113932396A (en) * 2020-07-13 2022-01-14 海信(山东)空调有限公司 Air conditioner and control method
CN113932396B (en) * 2020-07-13 2023-08-04 海信空调有限公司 Air conditioner and control method
CN112271919A (en) * 2020-11-06 2021-01-26 儒竞艾默生环境优化技术(上海)有限公司 Current compensation method, medium and current compensation device based on power factor correction
CN112271919B (en) * 2020-11-06 2021-09-21 上海儒竞智控技术有限公司 Current compensation method, medium and current compensation device based on power factor correction
CN113315391A (en) * 2021-04-29 2021-08-27 武汉华海通用电气有限公司 Digital PFC circuit

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