CN104953813B - The method and apparatus for preventing the output voltage overvoltage of PFC pfc circuit - Google Patents
The method and apparatus for preventing the output voltage overvoltage of PFC pfc circuit Download PDFInfo
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- CN104953813B CN104953813B CN201510367622.2A CN201510367622A CN104953813B CN 104953813 B CN104953813 B CN 104953813B CN 201510367622 A CN201510367622 A CN 201510367622A CN 104953813 B CN104953813 B CN 104953813B
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
- Y02B70/10—Technologies 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
Abstract
The invention discloses a kind of method and apparatus for the output voltage overvoltage for preventing pfc circuit, method comprises the following steps：Detect the input current instantaneous value and input voltage instantaneous value of pfc circuit, and the d-c bus voltage value of input current average value detection pfc circuit output end is calculated according to input current instantaneous value, and obtain DC bus-bar voltage and give, and according to d-c bus voltage value and the given step-up ratio Ka for obtaining pfc circuit of DC bus-bar voltage；The dutycycle of power switch pipe in pfc circuit is calculated according to step-up ratio Ka, input current instantaneous value and input current average value；Obtain the pressure-resistant higher limit of the electrochemical capacitor of pfc circuit output end, and the upper limit amplitude limit of dutycycle is calculated according to pressure-resistant higher limit and input voltage instantaneous value Vin, and the dutycycle for being output to power switch pipe is limited according to the upper limit amplitude limit of dutycycle to prevent the output voltage of pfc circuit from overvoltage occurs, so as to prevent that DC bus-bar voltage is too high, the device in equipment is avoided to be damaged because of overvoltage.
Description
Technical field
The present invention relates to household electrical appliance technical field, more particularly to a kind of output for preventing PFC pfc circuit
The method of electric voltage over press and a kind of device for the output voltage overvoltage for preventing PFC pfc circuit.
Background technology
In the equipment such as domestic air conditioning, to improve electrical source power factor, generally connect after uncontrollable full bridge rectifier
Pfc circuit such as Boost type circuit of power factor correction is connect, and big capacity electrolyte capacitor and load are connected after pfc circuit
(such as Switching Power Supply and compressor etc.), so, higher power factor can not only be reached by pfc circuit, and can be with
Boosting output steady dc voltage, galvanic current source is provided to load.
In the related art, Boost type circuit of power factor correction can be controlled using monocycle PFC control algolithm
System, specifically, monocycle PFC control algolithm can be calculated in pfc circuit and switched by outer voltage and monocycle current inner loop
The dutycycle of pipe.But correlation technique has the drawback that, high voltage is given (close to preset upper limit in DC bus-bar voltage
Voltage) when, overshoot may occur for the output of outer voltage, and then cause DC bus-bar voltage too high, cause the device in equipment
Damage；Or when DC bus-bar voltage stabilization is at high voltage (close to preset upper limit voltage), the decline of input current also may be used
DC bus-bar voltage can be caused too high, in turn result in the device failure in equipment.Therefore, correlation technique needs to improve.
The content of the invention
It is contemplated that at least solves one of technical problem in correlation technique to a certain extent.Therefore, the present invention
One purpose is to propose a kind of method for the output voltage overvoltage for preventing PFC pfc circuit, and this method can prevent
Only DC bus-bar voltage is too high, avoids the device in equipment from being damaged because of overvoltage.
It is another object of the present invention to propose a kind of output voltage overvoltage for preventing PFC pfc circuit
Device.
To reach above-mentioned purpose, the embodiment of the present invention proposes a kind of output electricity for preventing PFC pfc circuit
The method for pressing through pressure, comprises the following steps：Detect the input current instantaneous value Iinst of the pfc circuit and the pfc circuit
Input voltage instantaneous value Vin, and input current average value Iavg is calculated according to the input current instantaneous value Iinst；Detection institute
The d-c bus voltage value Vdc of pfc circuit output end is stated, and the DC bus-bar voltage for obtaining the pfc circuit output end gives
Vdc_ref, and Vdc_ref is given according to the d-c bus voltage value Vdc and the DC bus-bar voltage and obtains the PFC
The step-up ratio Ka of circuit；According to the step-up ratio Ka of the pfc circuit, the input current instantaneous value Iinst and the input electricity
Levelling average Iavg calculates the dutycycle of power switch pipe in the pfc circuit；Obtain the electrolysis electricity of the pfc circuit output end
The pressure-resistant higher limit Vdc_limit held, and according to the pressure-resistant higher limit Vdc_limit and the input voltage instantaneous value Vin
Calculate the upper limit amplitude limit of the dutycycle, and according to the upper limit amplitude limit of the dutycycle to being output to the power switch pipe
Dutycycle is limited to prevent the output voltage of the pfc circuit from overvoltage occurs.
The method for preventing that the output voltage of PFC pfc circuit is over-pressed proposed according to embodiments of the present invention, is obtained
Take the pressure-resistant higher limit Vdc_limit of the electrochemical capacitor of pfc circuit output end, and according to pressure-resistant higher limit Vdc_limit and defeated
Enter the upper limit amplitude limit that instantaneous voltage Vin calculates dutycycle, afterwards according to the upper limit amplitude limit of dutycycle to being output to power switch
The dutycycle of pipe is limited to prevent the output voltage of pfc circuit from overvoltage occurs.Thus, by accounting for power switch pipe
Sky can reach the purpose for preventing output voltage too high, and then prevent dc bus than carrying out amplitude limit to dutycycle before output
Overtension, the device in equipment is avoided to be damaged because of overvoltage.
According to one embodiment of present invention, the upper limit amplitude limit of the dutycycle can be calculated according to below equation：
Duty_max=1-Vin/Vdc_limit
Wherein, Duty_max is the upper limit amplitude limit of the dutycycle.
According to one embodiment of present invention, given according to the d-c bus voltage value Vdc and the DC bus-bar voltage
Determine the step-up ratio Ka that Vdc_ref obtains the pfc circuit, specifically include：Calculate the DC bus-bar voltage give Vdc_ref with
Voltage error value between the d-c bus voltage value Vdc；Proportional integration regulation is carried out to the voltage error value to obtain
The step-up ratio Ka of the pfc circuit.
According to one embodiment of present invention, accounting for for power switch pipe in the pfc circuit can be calculated according to below equation
Empty ratio：
Duty=1-Iinst/ (Ka*Iavg)
Wherein, Duty is the dutycycle of power switch pipe in the pfc circuit.
According to one embodiment of present invention, the delay of the voltage detecting passage of the input voltage instantaneous value Vin is detected
Time is less than the carrier cycle of 2 pfc circuits.
To reach above-mentioned purpose, inventive embodiments also proposed a kind of device for the output voltage overvoltage for preventing pfc circuit,
Including：First voltage detection module, for detecting the input voltage instantaneous value Vin of the pfc circuit；Second voltage detects mould
Block, for detecting the d-c bus voltage value Vdc of the pfc circuit output end；First current detection module, it is described for detecting
The input current instantaneous value Iinst of pfc circuit；Control module, inputted for being calculated according to the input current instantaneous value Iinst
Current average Iavg, and the DC bus-bar voltage for obtaining the pfc circuit output end gives Vdc_ref, and according to described
D-c bus voltage value Vdc and the DC bus-bar voltage give the step-up ratio Ka that Vdc_ref obtains the pfc circuit, and root
Institute is calculated according to the step-up ratio Ka of the pfc circuit, the input current instantaneous value Iinst and the input current average value Iavg
The dutycycle of power switch pipe in pfc circuit is stated, and the control module is additionally operable to obtain the electricity of the pfc circuit output end
The pressure-resistant higher limit Vdc_limit of electric capacity is solved, and according to the pressure-resistant higher limit Vdc_limit and the input voltage instantaneous value
Vin calculates the upper limit amplitude limit of the dutycycle, and according to the upper limit amplitude limit of the dutycycle to being output to the power switch
The dutycycle of pipe is limited to prevent the output voltage of the pfc circuit from overvoltage occurs.
What is proposed according to embodiments of the present invention prevents the device of the output voltage overvoltage of PFC pfc circuit, control
Molding block obtains the pressure-resistant higher limit Vdc_limit of the electrochemical capacitor of pfc circuit output end, and according to pressure-resistant higher limit Vdc_
Limit and input voltage instantaneous value Vin calculates the upper limit amplitude limit of dutycycle, afterwards according to the upper limit amplitude limit of dutycycle to being output to
The dutycycle of power switch pipe is limited to prevent the output voltage of pfc circuit from overvoltage occurs.Thus, by being opened by power
Amplitude limit is carried out to dutycycle before closing the dutycycle output of pipe, the purpose for preventing output voltage too high can be reached, and then prevent
DC bus-bar voltage is too high, avoids the device in equipment from being damaged because of overvoltage.
According to one embodiment of present invention, the control module calculates the upper limit limit of the dutycycle according to below equation
Width：
Duty_max=1-Vin/Vdc_limit
Wherein, Duty_max is the upper limit amplitude limit of the dutycycle.
According to one embodiment of present invention, the control module passes through when obtaining the step-up ratio Ka of the pfc circuit
Calculate the given voltage error value between Vdc_ref and the d-c bus voltage value Vdc of the DC bus-bar voltage and right
Proportional integration regulation is carried out to the voltage error value to obtain the step-up ratio Ka of the pfc circuit.
According to one embodiment of present invention, the control module calculates power in the pfc circuit according to below equation
The dutycycle of switching tube：
Duty=1-Iinst/ (Ka*Iavg)
Wherein, Duty is the dutycycle of power switch pipe in the pfc circuit.
According to one embodiment of present invention, the delay time of the voltage detecting passage of the first voltage detection module is small
In the carrier cycle of 2 pfc circuits.
Brief description of the drawings
Fig. 1 is the flow chart of the method for the output voltage overvoltage for preventing pfc circuit according to embodiments of the present invention；
Fig. 2 is the block diagram of the device of the output voltage overvoltage for preventing pfc circuit according to embodiments of the present invention；With
And
Fig. 3 is the control principle of the device of the output voltage overvoltage according to an embodiment of the invention for preventing pfc circuit
Figure.
Embodiment
Embodiments of the invention are described below in detail, the example of the embodiment is shown in the drawings, wherein from beginning to end
Same or similar label represents same or similar element or the element with same or like function.Below with reference to attached
The embodiment of figure description is exemplary, it is intended to for explaining the present invention, and is not considered as limiting the invention.
Below with reference to the accompanying drawings come describe the embodiment of the present invention proposition the output voltage for preventing PFC pfc circuit
The method and apparatus of overvoltage.
Fig. 1 is according to embodiments of the present invention to prevent PFC PFC (Power Factor Correction, work(
Rate factor correcting) circuit output voltage overvoltage method flow chart.As shown in figure 1, this method comprises the following steps：
S1：Detect the input current instantaneous value Iinst of pfc circuit and the input voltage instantaneous value Vin of pfc circuit, and root
Input current average value Iavg is calculated according to input current instantaneous value Iinst.
Wherein, the input current instantaneous value Iinst of pfc circuit can be detected by resistance sampling method, and resistance can be passed through
Partial pressure method detects the input voltage instantaneous value Vin of pfc circuit.
According to one embodiment of present invention, low pass can be carried out to input current instantaneous value Iinst by low pass filter
Filter to calculate input current average value Iavg.
Wherein, the cut-off frequency of low pass filter much smaller than pfc circuit input current frequency, such as much smaller than
100Hz, it is preferable that cut-off frequency 8Hz.
S2：The d-c bus voltage value Vdc of pfc circuit output end is detected, and obtains the dc bus of pfc circuit output end
Voltage gives Vdc_ref, and gives Vdc_ref according to d-c bus voltage value Vdc and DC bus-bar voltage and obtain pfc circuit
Step-up ratio Ka.
That is, as shown in figure 3, outer voltage can give according to d-c bus voltage value Vdc and DC bus-bar voltage
Vdc_ref and passing ratio-integral controller obtain the step-up ratio Ka of pfc circuit.Wherein, can be detected by electric resistance partial pressure method
The d-c bus voltage value Vdc of pfc circuit output end.
Specifically, according to one embodiment of present invention, given according to d-c bus voltage value Vdc and DC bus-bar voltage
Vdc_ref obtains the step-up ratio Ka of pfc circuit, specifically includes：Calculate DC bus-bar voltage and give Vdc_ref and dc bus electricity
Voltage error value between pressure value Vdc；Proportional integration regulation is carried out to voltage error value to obtain the step-up ratio Ka of pfc circuit.
That is, as shown in figure 3, DC bus-bar voltage can be given between Vdc_ref and d-c bus voltage value Vdc
Input of the voltage error value as proportional-integral controller, proportional-integral controller adjusts to the voltage error value of input
Save and then export step-up ratio Ka.
It should be noted that when outer voltage is operated in stable state, step-up ratio Ka steady-state value is given for DC bus-bar voltage
Determine Vdc_ref and input voltage average value Vin_avg ratio, i.e. Ka=Vdc_ref/Vin_avg.It is it should be appreciated that defeated
It is similar with input current average value Iavg acquisition modes to enter average voltage Vin_avg acquisition modes, in succinct mesh
, do not repeating here.
S3：Calculated according to the step-up ratio Ka, input current instantaneous value Iinst and input current average value Iavg of pfc circuit
The dutycycle of power switch pipe in pfc circuit.
That is, as shown in figure 3, current inner loop can be according to step-up ratio Ka, input current instantaneous value Iinst and input electricity
Levelling average Iavg simultaneously calculates output to the dutycycle Duty of the pwm signal of power switch pipe by monocycle method, so that PFC
Power switch pipe in circuit is switched on or off under the control of pwm signal.
It should be noted that when the step-up ratio Ka of outer voltage output reaches stable state (steady or slowly varying), lead to
Crossing monocycle current inner loop can realize that input current instantaneous value Iinst tracks input voltage instantaneous value Vin waveforms, reach close
The power factor of unit 1.
Specifically, according to one embodiment of present invention, power switch pipe in pfc circuit can be calculated according to below equation
Dutycycle：
Duty=1-Iinst/ (Ka*Iavg)
Wherein, Duty is the dutycycle of power switch pipe in pfc circuit.
S4：The pressure-resistant higher limit Vdc_limit of the electrochemical capacitor of pfc circuit output end is obtained, and according to pressure-resistant higher limit
Vdc_limit and input voltage instantaneous value Vin calculate the upper limit amplitude limit of dutycycle, and according to the upper limit amplitude limit of dutycycle to defeated
The dutycycle gone out to power switch pipe is limited to prevent the output voltage of pfc circuit from overvoltage occurs.
That is, after the dutycycle of power switch pipe is calculated, can be by the dutycycle and duty of power switch pipe
The upper limit amplitude limit of ratio is compared, if the dutycycle of power switch pipe is more than the upper limit amplitude limit of dutycycle, to being output to work(
The dutycycle of rate switching tube is limited, and the duty cycle limit of switching tube is made as to the upper limit amplitude limit of dutycycle, that is, is output to power
The dutycycle of switching tube is the upper limit amplitude limit of dutycycle；If the dutycycle of power switch pipe is less than or equal to the upper limit of dutycycle
Amplitude limit, then the dutycycle for being output to power switch pipe is not limited, the dutycycle calculated directly is output into power opens
Guan Guan.
According to the specific example of the present invention, the pressure-resistant higher limit Vdc_limit of electrochemical capacitor can be 400V.
Specifically, according to one embodiment of present invention, the upper limit amplitude limit of dutycycle can be calculated according to below equation：
Duty_max=1-Vin/Vdc_limit
Wherein, Duty_max is the upper limit amplitude limit of dutycycle.
As described above, in embodiments of the present invention, as shown in figure 3, using monocycle PFC control algolithm to pfc circuit
During being controlled, the input current instantaneous value Iinst of detection pfc circuit and the input voltage of pfc circuit are instantaneous in real time
Value Vin, outer voltage give Vdc_ref and DC bus-bar voltage instantaneous value Vdc and passing ratio-product according to DC bus-bar voltage
Divide adjuster output step-up ratio Ka；Current inner loop calculates the dutycycle of pwm signal according to step-up ratio Ka and by monocycle method
Duty.Afterwards, exported by dutycycle Duty to before power switch pipe, the upper limit amplitude limit of dutycycle Duty and dutycycle is entered
Row compares, if dutycycle Duty exceedes the upper limit amplitude limit of dutycycle, the upper limit that dutycycle Duty is limited to dutycycle limits
Width；If not less than the upper limit amplitude limit of dutycycle, direct output duty cycle Duty, so as to so that the output voltage of pfc circuit
That is d-c bus voltage value Vdc meets the pressure-resistant of electrochemical capacitor side not over the pressure-resistant higher limit Vdc_limit of electrochemical capacitor
Demand, device is avoided to be damaged because of overvoltage.
In addition, during being controlled to pfc circuit using monocycle PFC control algolithm, can further comparative example-
The step-up ratio Ka of integral controller output adjustable range is adjusted.When the input current of pfc circuit is in uphill process
, can be by the tune of step-up ratio when (or bearing power is in increase process or the input voltage of pfc circuit is in reduction process)
The section upper limit is arranged to Vdc_limit/Vin_avg, and the regulation lower limit of step-up ratio is arranged to the first regulation lower limit (Vdc_ref/Vin_
Avg) * λ 1, so that step-up ratio Ka can adjust higher value, avoid proportional-integral controller is too fast from entering positive saturation
State, the dutycycle that improvement current inner loop is calculated situation less than normal because of input current average value Iavg hysteresis.When PFC electricity
The input current on road is in decline during (or bearing power is in reduction process or the input voltage of pfc circuit is in
Elevation process) when, the regulation upper limit of step-up ratio can be arranged to Vdc_limit/Vin_avg, the regulation lower limit of step-up ratio is set
For the second regulation lower limit (Vdc_ref/Vin_avg) * λ 2 so that step-up ratio Ka can adjust lower value, avoid ratio-
Integral controller is too fast to enter negative sense saturation state, and the dutycycle that improvement current inner loop is calculated is because of input current average value
Iavg is lagged and situation bigger than normal.
According to one embodiment of present invention, pwm signal can be by carrier wave by being generated after modulating wave modulation, can be each
A step S1-S4 is performed in the cycle of carrier wave, that is to say, that an input voltage wink can be detected within the cycle of each carrier wave
Duration Vin and input current instantaneous value Iinst.
Also, according to one embodiment of present invention, detect the delay of input voltage instantaneous value Vin voltage detecting passage
Time is less than the carrier cycle of 2 pfc circuits.Preferably, when the carrier cycle of pfc circuit is 25us, voltage detecting passage
Delay time can be 33us.
In summary, what is proposed according to embodiments of the present invention prevents the output voltage overvoltage of PFC pfc circuit
Method, the pressure-resistant higher limit Vdc_limit of the electrochemical capacitor of pfc circuit output end is obtained, and according to pressure-resistant higher limit Vdc_
Limit and input voltage instantaneous value Vin calculates the upper limit amplitude limit of dutycycle, afterwards according to the upper limit amplitude limit of dutycycle to being output to
The dutycycle of power switch pipe is limited to prevent the output voltage of pfc circuit from overvoltage occurs.Thus, by being opened by power
Amplitude limit is carried out to dutycycle before closing the dutycycle output of pipe, the purpose for preventing output voltage too high can be reached, and then prevent
DC bus-bar voltage is too high, avoids the device in equipment from being damaged because of overvoltage.
In order to perform above-described embodiment, the embodiment of the present invention also proposed a kind of output voltage overvoltage for preventing pfc circuit
Device.
Fig. 2 is the device of the output voltage overvoltage for preventing pfc circuit according to embodiments of the present invention.Such as Fig. 2 and Fig. 3 institutes
Show, the device includes：First voltage detection module 10, second voltage detection module 20, the first current detection module 30 and control
Module 40.
According to one embodiment of present invention, as shown in figure 3, pfc circuit 200 is attached to rectifier bridge 100 and electrolysis electricity
Between holding E1, electrochemical capacitor E1 is in parallel with load 300, and pfc circuit 200 may include the first inductance L1, power switch tube S 1 and two
Pole pipe D1.Specifically, rectifier bridge 100 is used to carry out rectification to alternating current to obtain the direct current after rectification, and pfc circuit 200 is used
In carrying out PFC to power supply, and boosting processing is carried out to the direct current after rectification, think that electrochemical capacitor and load carry
For steady dc voltage.
As shown in Figures 2 and 3, first voltage detection module 10 is used for the input voltage instantaneous value for detecting pfc circuit 200
Vin；Second voltage detection module 20 is used for the d-c bus voltage value Vdc for detecting the output end of pfc circuit 200；First electric current is examined
Survey the input current instantaneous value Iinst that module 30 is used to detect pfc circuit 200.Wherein, the first current detection module 30 can pass through
Resistance sampling method detects the input current instantaneous value Iinst of pfc circuit 200, and first voltage detection module 10 can pass through electricity
The input voltage instantaneous value Vin of partial pressure method detection pfc circuit 200 is hindered, and second voltage detection module 20 can pass through resistance point
Platen press detects the d-c bus voltage value Vdc of the output end of pfc circuit 200.
Control module 40 is used to calculate input current average value Iavg according to input current instantaneous value Iinst, and obtains PFC
The DC bus-bar voltage of the output end of circuit 200 gives Vdc_ref, and according to d-c bus voltage value Vdc and dc bus electricity
The given Vdc_ref of pressure obtains the step-up ratio Ka of pfc circuit, and according to the step-up ratio Ka of pfc circuit, input current instantaneous value
Iinst and input current average value Iavg calculates the dutycycle of power switch tube S 1 in pfc circuit 200, and control module 40
It is additionally operable to obtain the pressure-resistant higher limit Vdc_limit of the electrochemical capacitor of the output end of pfc circuit 200, and according to pressure-resistant higher limit
Vdc_limit and input voltage instantaneous value Vin calculate the upper limit amplitude limit of dutycycle, and according to the upper limit amplitude limit of dutycycle to defeated
The dutycycle gone out to power switch tube S 1 is limited to prevent the output voltage of pfc circuit 200 from overvoltage occurs.According to the present invention
A specific example, the pressure-resistant higher limit Vdc_limit of electrochemical capacitor can be 400V.
Wherein, according to one embodiment of present invention, control module 40 can calculate the upper limit of dutycycle according to below equation
Amplitude limit：
Duty_max=1-Vin/Vdc_limit
Wherein, Duty_max is the upper limit amplitude limit of dutycycle.
That is, control module 40 is after the dutycycle of power switch tube S 1 is calculated, can be by power switch tube S 1
Dutycycle compared with the upper limit amplitude limit of dutycycle, if the dutycycle of power switch tube S 1 be more than dutycycle the upper limit limit
Width, then control module 40 dutycycle for being output to power switch tube S 1 is limited, the duty cycle limit of switching tube is made as accounting for
The upper limit amplitude limit of empty ratio, that is, the dutycycle for being output to power switch tube S 1 is the upper limit amplitude limit of dutycycle；If power switch pipe
S1 dutycycle is less than or equal to the upper limit amplitude limit of dutycycle, then control module 40 is not to being output to the duty of power switch tube S 1
Than being limited, the dutycycle calculated is directly output to power switch tube S 1.
As described above, in embodiments of the present invention, as shown in figure 3, using monocycle PFC control algolithm to pfc circuit
During being controlled, pfc circuit can be detected in real time by the current detection module 30 of first voltage detection module 10 and first
Input current instantaneous value Iinst and pfc circuit input voltage instantaneous value Vin, outer voltage gives according to DC bus-bar voltage
Determine Vdc_ref and DC bus-bar voltage instantaneous value Vdc and passing ratio-integral controller 1 exports step-up ratio Ka；Current inner loop can
Calculated according to step-up ratio Ka, input current instantaneous value Iinst and input current average value Iavg and by monocycle calculator 2 defeated
Go out to the dutycycle Duty of the pwm signal of power switch tube S 1, so that the power switch tube S 1 in pfc circuit 200 is in pwm signal
Control under be switched on or off, wherein, control module 40 according to below equation calculate pfc circuit in power switch pipe duty
Than：Duty=1-Iinst/ (Ka*Iavg), wherein, Duty is the dutycycle of power switch pipe in pfc circuit.
Afterwards, control module 40 is exported to before power switch pipe by dutycycle Duty, first by dutycycle Duty with accounting for
The upper limit amplitude limit of empty ratio is compared, if dutycycle Duty exceedes the upper limit amplitude limit of dutycycle, dutycycle Duty is limited
For the upper limit amplitude limit of dutycycle；If not less than the upper limit amplitude limit of dutycycle, direct output duty cycle Duty, so as to so that
The output voltage of pfc circuit is pressure-resistant higher limit Vdc_limits of the d-c bus voltage value Vdc not over electrochemical capacitor, full
The pressure-resistant demand of sufficient electrochemical capacitor side, device is avoided to be damaged because of overvoltage.
It should be noted that when the step-up ratio Ka of outer voltage output reaches stable state (steady or slowly varying), lead to
Crossing monocycle current inner loop can realize that input current instantaneous value Iinst tracks input voltage instantaneous value Vin waveforms, reach close
The power factor of unit 1.
According to one embodiment of present invention, control module 40 can be by low pass filter to input current instantaneous value
Iinst carries out LPF to calculate input current average value Iavg.Wherein, the cut-off frequency of low pass filter is much smaller than PFC
The frequency of the input current of circuit 200, such as much smaller than 100Hz, it is preferable that cut-off frequency 8Hz.
Specifically, according to one embodiment of present invention, control module 40 obtain pfc circuit 200 step-up ratio Ka when,
By calculating the given voltage error value between Vdc_ref and d-c bus voltage value Vdc of DC bus-bar voltage and to electricity
Hold up difference and carry out proportional integration regulation to obtain the step-up ratio Ka of pfc circuit 200.
That is, as shown in figure 3, control module 40 can give DC bus-bar voltage Vdc_ref and dc bus electricity
Input of the voltage error value as proportional-integral controller 1 between pressure value Vdc, electricity of the proportional-integral controller 1 to input
Difference is held up to be adjusted and then export step-up ratio Ka.
It should be noted that when outer voltage is operated in stable state, step-up ratio Ka steady-state value is given for DC bus-bar voltage
Determine Vdc_ref and input voltage average value Vin_avg ratio, i.e. Ka=Vdc_ref/Vin_avg.It is it should be appreciated that defeated
It is similar with input current average value Iavg acquisition modes to enter average voltage Vin_avg acquisition modes, in succinct mesh
, do not repeating here.
It should be noted that when the step-up ratio Ka of outer voltage output reaches stable state (steady or slowly varying), lead to
Crossing monocycle current inner loop can realize that input current instantaneous value Iinst tracks input voltage instantaneous value Vin waveforms, reach close
The power factor of unit 1.
Also, during being controlled using monocycle PFC control algolithm to pfc circuit 200, control module 40 can
The adjustable range for the step-up ratio Ka that further comparative example-integral controller 1 exports is adjusted.When the input electricity of pfc circuit 200
Stream is in uphill process (or bearing power is in increase process or the input voltage of pfc circuit is in reduction process)
When, the regulation upper limit of step-up ratio can be arranged to Vdc_limit/Vin_avg by control module 40, and the regulation lower limit of step-up ratio is set
For the first regulation lower limit, so that step-up ratio Ka can adjust higher value, 1 too fast entrance of proportional-integral controller is avoided
Positive saturation state, the dutycycle that improvement current inner loop is calculated feelings less than normal because of input current average value Iavg hysteresis
Condition.During the input current of pfc circuit 200 is in and declined (or bearing power is in reduction process or pfc circuit
Input voltage be in elevation process) when, the regulation upper limit of step-up ratio can be arranged to Vdc_limit/Vin_ by control module 40
Avg, the regulation lower limit of step-up ratio are arranged to the second regulation lower limit, so that step-up ratio Ka can adjust lower value, avoided
Proportional-integral controller 1 is too fast to enter negative sense saturation state, and the dutycycle that improvement current inner loop is calculated is because input current is put down
Average Iavg is lagged and situation bigger than normal.
According to one embodiment of present invention, pwm signal can be by carrier wave by being generated after modulating wave modulation, can be each
One-time detection and duty-cycle limit are performed in the cycle of carrier wave, that is to say, that the electric current of first voltage detection module 10 and first is examined
An input voltage instantaneous value Vin and input current instantaneous value Iinst can be detected within the cycle of each carrier wave by surveying module 30.
Also, according to one embodiment of present invention, during the delay of the voltage detecting passage of first voltage detection module 10
Between be less than the carrier cycles of 2 pfc circuits.Preferably, when the carrier cycle of pfc circuit is 25us, first voltage detection mould
The delay time of the voltage detecting passage of block 10 can be 33us.
In summary, what is proposed according to embodiments of the present invention prevents the output voltage overvoltage of PFC pfc circuit
Device, control module obtains the pressure-resistant higher limit Vdc_limit of the electrochemical capacitor of pfc circuit output end, and according on pressure-resistant
Limit value Vdc_limit and input voltage instantaneous value Vin calculates the upper limit amplitude limit of dutycycle, afterwards according to the upper limit amplitude limit of dutycycle
The dutycycle for being output to power switch pipe is limited to prevent the output voltage of pfc circuit from overvoltage occurs.Thus, by
Amplitude limit will be carried out to dutycycle before the dutycycle output of power switch pipe, the purpose for preventing output voltage too high can be reached,
And then prevent that DC bus-bar voltage is too high, avoid the device in equipment from being damaged because of overvoltage.
In the description of the invention, it is to be understood that term " " center ", " longitudinal direction ", " transverse direction ", " length ", " width ",
" thickness ", " on ", " under ", "front", "rear", "left", "right", " vertical ", " level ", " top ", " bottom " " interior ", " outer ", " up time
The orientation or position relationship of the instruction such as pin ", " counterclockwise ", " axial direction ", " radial direction ", " circumference " be based on orientation shown in the drawings or
Position relationship, it is for only for ease of and describes the present invention and simplify description, rather than indicates or imply that signified device or element must
There must be specific orientation, with specific azimuth configuration and operation, therefore be not considered as limiting the invention.
In addition, term " first ", " second " are only used for describing purpose, and it is not intended that instruction or hint relative importance
Or the implicit quantity for indicating indicated technical characteristic.Thus, define " first ", the feature of " second " can be expressed or
Implicitly include at least one this feature.In the description of the invention, " multiple " are meant that at least two, such as two, three
It is individual etc., unless otherwise specifically defined.
In the present invention, unless otherwise clearly defined and limited, term " installation ", " connected ", " connection ", " fixation " etc.
Term should be interpreted broadly, for example, it may be fixedly connected or be detachably connected, or integrally；Can be that machinery connects
Connect or electrically connect；Can be joined directly together, can also be indirectly connected by intermediary, can be in two elements
The connection in portion or the interaction relationship of two elements, limited unless otherwise clear and definite.For one of ordinary skill in the art
For, the concrete meaning of above-mentioned term in the present invention can be understood as the case may be.
In the present invention, unless otherwise clearly defined and limited, fisrt feature can be with "above" or "below" second feature
It is that the first and second features directly contact, or the first and second features pass through intermediary mediate contact.Moreover, fisrt feature exists
Second feature " on ", " top " and " above " but fisrt feature are directly over second feature or oblique upper, or be merely representative of
Fisrt feature level height is higher than second feature.Fisrt feature second feature " under ", " lower section " and " below " can be
One feature is immediately below second feature or obliquely downward, or is merely representative of fisrt feature level height and is less than second feature.
In the description of this specification, reference term " one embodiment ", " some embodiments ", " example ", " specifically show
The description of example " or " some examples " etc. means specific features, structure, material or the spy for combining the embodiment or example description
Point is contained at least one embodiment or example of the present invention.In this manual, to the schematic representation of above-mentioned term not
Identical embodiment or example must be directed to.Moreover, specific features, structure, material or the feature of description can be with office
Combined in an appropriate manner in one or more embodiments or example.In addition, in the case of not conflicting, the skill of this area
Art personnel can be tied the different embodiments or example and the feature of different embodiments or example described in this specification
Close and combine.
Although embodiments of the invention have been shown and described above, it is to be understood that above-described embodiment is example
Property, it is impossible to limitation of the present invention is interpreted as, one of ordinary skill in the art within the scope of the invention can be to above-mentioned
Embodiment is changed, changed, replacing and modification.
Claims (8)
- A kind of 1. method for the output voltage overvoltage for preventing PFC pfc circuit, it is characterised in that including following step Suddenly：Detect the input current instantaneous value Iinst of the pfc circuit and the input voltage instantaneous value Vin of the pfc circuit, and root Input current average value Iavg is calculated according to the input current instantaneous value Iinst；Wherein, the delay time for detecting the voltage detecting passage of the input voltage instantaneous value Vin is less than 2 pfc circuits Carrier cycle；The d-c bus voltage value Vdc of the pfc circuit output end is detected, and the direct current for obtaining the pfc circuit output end is female Line voltage gives Vdc_ref, and gives Vdc_ref according to the d-c bus voltage value Vdc and the DC bus-bar voltage Obtain the step-up ratio Ka of the pfc circuit；According to the step-up ratio Ka of the pfc circuit, the input current instantaneous value Iinst and the input current average value Iavg Calculate the dutycycle of power switch pipe in the pfc circuit；The pressure-resistant higher limit Vdc_limit of the electrochemical capacitor of the pfc circuit output end is obtained, and according to the pressure-resistant higher limit The Vdc_limit and input voltage instantaneous value Vin calculates the upper limit amplitude limit of the dutycycle, and according to the dutycycle Upper limit amplitude limit is limited the dutycycle for being output to the power switch pipe to prevent the output voltage of the pfc circuit from occurring Overvoltage.
- 2. according to the method for claim 1, it is characterised in that the upper limit that the dutycycle is calculated according to below equation limits Width：Duty_max=1-Vin/Vdc_limitWherein, Duty_max is the upper limit amplitude limit of the dutycycle.
- 3. according to the method for claim 1, it is characterised in that according to the d-c bus voltage value Vdc and the direct current Busbar voltage gives the step-up ratio Ka that Vdc_ref obtains the pfc circuit, specifically includes：Calculate the given voltage error value between Vdc_ref and the d-c bus voltage value Vdc of the DC bus-bar voltage；Proportional integration regulation is carried out to the voltage error value to obtain the step-up ratio Ka of the pfc circuit.
- 4. according to the method for claim 1, it is characterised in that power in the pfc circuit is calculated according to below equation and opened Close the dutycycle of pipe：Duty=1-Iinst/ (Ka*Iavg)Wherein, Duty is the dutycycle of power switch pipe in the pfc circuit.
- A kind of 5. device for the output voltage overvoltage for preventing pfc circuit, it is characterised in that including：First voltage detection module, for detecting the input voltage instantaneous value Vin of the pfc circuit；Wherein, the delay time of the voltage detecting passage of the first voltage detection module is less than the carrier wave of 2 pfc circuits Cycle；Second voltage detection module, for detecting the d-c bus voltage value Vdc of the pfc circuit output end；First current detection module, for detecting the input current instantaneous value Iinst of the pfc circuit；Control module, for calculating input current average value Iavg according to the input current instantaneous value Iinst, and described in acquisition The DC bus-bar voltage of pfc circuit output end gives Vdc_ref, and according to the d-c bus voltage value Vdc and described straight Flow busbar voltage and give the step-up ratio Ka that Vdc_ref obtains the pfc circuit, and according to the step-up ratio Ka of the pfc circuit, institute State input current instantaneous value Iinst and the input current average value Iavg and calculate accounting for for power switch pipe in the pfc circuit Empty ratio, and the control module are additionally operable to obtain the pressure-resistant higher limit Vdc_ of the electrochemical capacitor of the pfc circuit output end Limit, and the upper of the dutycycle is calculated according to the pressure-resistant higher limit Vdc_limit and input voltage instantaneous value Vin Limit amplitude limit, and according to the upper limit amplitude limit of the dutycycle dutycycle for being output to the power switch pipe is limited to prevent Only overvoltage occurs for the output voltage of the pfc circuit.
- 6. device according to claim 5, it is characterised in that the control module calculates the duty according to below equation The upper limit amplitude limit of ratio：Duty_max=1-Vin/Vdc_limitWherein, Duty_max is the upper limit amplitude limit of the dutycycle.
- 7. device according to claim 5, it is characterised in that the control module is obtaining the boosting of the pfc circuit During than Ka, missed by calculating the given voltage between Vdc_ref and the d-c bus voltage value Vdc of the DC bus-bar voltage Difference and to carrying out proportional integration regulation to the voltage error value to obtain the step-up ratio Ka of the pfc circuit.
- 8. device according to claim 5, it is characterised in that the control module calculates the PFC according to below equation The dutycycle of power switch pipe in circuit：Duty=1-Iinst/ (Ka*Iavg)Wherein, Duty is the dutycycle of power switch pipe in the pfc circuit.
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| CN201510367622.2A CN104953813B (en) | 2015-06-26 | 2015-06-26 | The method and apparatus for preventing the output voltage overvoltage of PFC pfc circuit |
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| CN201510367622.2A CN104953813B (en) | 2015-06-26 | 2015-06-26 | The method and apparatus for preventing the output voltage overvoltage of PFC pfc circuit |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN106771506A (en) * | 2016-12-15 | 2017-05-31 | 四川长虹电器股份有限公司 | Air-conditioner outdoor unit running current detection method |
| CN107070364B (en) * | 2017-03-31 | 2019-08-30 | 广东美的制冷设备有限公司 | Air conditioner, motor driver and its anti-cross heat control method and device |
| CN108270352A (en) * | 2018-01-29 | 2018-07-10 | 青岛海尔空调电子有限公司 | PFC circuit control method, circuit control system and air conditioner |
| CN108322038B (en) * | 2018-02-08 | 2020-05-08 | 佛山市顺德区和而泰电子科技有限公司 | PFC circuit control method and loop-free PFC control circuit applying same |
| CN108809073B (en) * | 2018-05-31 | 2020-01-17 | 奥克斯空调股份有限公司 | APFC circuit voltage control method and system and air conditioner |
| CN109617388A (en) * | 2019-01-14 | 2019-04-12 | 四川虹美智能科技有限公司 | A kind of power factor correction control method |
| CN111697813B (en) * | 2019-03-13 | 2022-03-04 | 青岛海尔智能技术研发有限公司 | Frequency conversion equipment, control method and device of PFC circuit of frequency conversion equipment and storage medium |
| CN112212460B (en) * | 2020-08-28 | 2022-03-08 | 海信（山东）空调有限公司 | Air conditioner and shutdown control method |
| CN112636579B (en) * | 2020-12-07 | 2022-05-06 | 佛山市顺德区美的电子科技有限公司 | Control method and device of PFC circuit, computer readable storage medium and controller |
| CN113037069B (en) * | 2021-03-12 | 2022-07-15 | 杰华特微电子股份有限公司 | Switch protection circuit and power converter |
| CN113162448B (en) * | 2021-04-27 | 2023-04-18 | 深圳市能隙科技有限公司 | Three-level converter bus balance control method, device, equipment and medium |
| CN113541470B (en) * | 2021-06-21 | 2023-02-28 | 深圳市禾望科技有限公司 | DC/DC converter, control method thereof and photovoltaic power generation system |
| CN113872431B (en) * | 2021-11-03 | 2023-10-10 | 珠海格力电器股份有限公司 | Circuit control device and method |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| US20020196006A1 (en) * | 2001-06-21 | 2002-12-26 | Champion Microelectronic Corp. | Volt-second balanced PFCPWM power converter |
| CN101404446B (en) * | 2008-11-11 | 2011-02-16 | 珠海格力电器股份有限公司 | Monocycle power factor emendation method |
| CN101546963A (en) * | 2009-04-22 | 2009-09-30 | 南京航空航天大学 | Digital monocyclic control method of PFC converter |
| CN102005777B (en) * | 2010-11-04 | 2013-03-06 | 艾默生网络能源有限公司 | Control method and control system for photovoltaic grid-connected inverter |
| CN103580469B (en) * | 2012-07-25 | 2016-04-27 | 海尔集团公司 | A kind of power factor correcting method for permagnetic synchronous motor |
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