WO2018232818A1

WO2018232818A1 - Method and device for obtaining effective value of alternating current voltage of pfc power supply

Info

Publication number: WO2018232818A1
Application number: PCT/CN2017/094173
Authority: WO
Inventors: 黄招彬
Original assignee: 广东美的制冷设备有限公司
Priority date: 2017-06-21
Filing date: 2017-07-24
Publication date: 2018-12-27
Also published as: CN107276386A; CN107276386B

Abstract

A method and device for obtaining an effective value of an alternating current voltage of a power factor correction (PFC) power supply. The method for obtaining an effective value of an alternating current voltage of a PFC power supply comprises the following steps: acquiring current operating parameters of a PFC power supply (S100); when the current operating parameters of the PFC power supply meet a condition for a power factor correction circuit of the PFC power supply to be turned off, controlling the power factor correction circuit of the PFC power supply to turn off, and according to the voltage of two ends of an electrolytic capacitor, obtaining a peak value of an input alternating current voltage of the PFC power supply (S200); when the current operating parameters of the PFC power supply meet a condition for the power factor correction circuit of the PFC power supply to be turned on, controlling the power factor correction circuit to turn on, and according to an operating mode of the power factor correction circuit, obtaining an instantaneous value of the input alternating current voltage of the PFC power supply (S300); according to the peak value of the input alternating current voltage or the instantaneous value of the input alternating current voltage, calculating an effective value of the alternating current voltage of the PFC power supply (S400). The method and device have the characteristic of high accuracy.

Description

Method and device for obtaining AC voltage effective value of PFC power source

Technical field

The present invention relates to the field of power electronics, and in particular, to a method and an apparatus for acquiring an ac voltage of an AC voltage of a PFC power source.

Background technique

In household appliances and other similar systems: single-phase AC power from the grid, first through uncontrollable full-bridge rectification, then through the power factor correction circuit, and finally output DC power to power large-capacity electrolytic capacitors and loads. Among them, the power factor correction circuit generally adopts the BOOST architecture. The BOOST type power factor correction circuit not only enables the power supply circuit to achieve a higher power factor, but also boosts the output of a stable DC bus voltage to provide a stable DC power supply for the load.

There are various control methods for BOOST type power factor correction, such as voltage/current double closed loop control algorithm, single period control algorithm, and so on. From the perspective of power factor correction, the single-cycle control algorithm can eliminate the need for AC voltage as an input and cancel the AC voltage sampling circuit. However, in most electrical systems, AC voltage is required as a protection threshold or other control input parameters. The AC voltage RMS estimation is performed on the basis of canceling the AC voltage sampling circuit.

The prior art adopts the following method to obtain the effective value of the AC voltage of the PFC power source: when the current is small, the estimated voltage peak value is used to calculate the effective value, and when the current is large, the estimated voltage instantaneous value is used to calculate the effective value. Wherein, in any one of the switching cycles of the power switching tube in the power factor correction circuit, the instantaneous value of the voltage is related to the amount of change in the inductor current, the rise time of the inductor current, and the fall time of the inductor current.

Since when the power factor correction circuit operates in the inductor current interrupt mode, the time of the inductor current drop cannot be known. Therefore, the prior art cannot avoid the AC voltage estimation error in the power factor correction circuit current intermittent operation state, which is easy to cause estimation. The problem that the RMS value of the AC voltage is too large.

Summary of the invention

The main object of the present invention is to provide an AC voltage RMS acquisition method for a PFC power supply, which aims to improve the accuracy of the AC voltage RMS acquisition result of the PFC power supply.

To achieve the above objective, the AC voltage RMS acquisition method of the PFC power supply provided by the present invention includes the following steps:

S100. Obtain a current working parameter of the PFC power supply.

S200. When the current operating parameter of the PFC power supply meets the condition that the power factor correction circuit of the PFC power supply is turned off, the power factor correction circuit that controls the PFC power supply is turned off, and the voltage across the electrolytic capacitor of the PFC power supply is obtained, and then according to the electrolysis. The voltage across the capacitor acquires the peak value of the input AC voltage of the PFC power supply;

S300. When the current operating parameter of the PFC power supply meets a condition that the power factor correction circuit of the PFC power supply is turned on, control the power factor correction circuit to be turned on, and determine an operation mode of the power factor correction circuit, and then according to the power. The working mode of the factor correction circuit acquires an instantaneous value of the input AC voltage of the PFC power source;

S400. Calculate an RMS effective value of the PFC power source according to the input AC voltage peak value or the input AC voltage instantaneous value.

Preferably, the obtaining the voltage across the electrolytic capacitor of the PFC power supply, and then obtaining the peak value of the input AC voltage of the PFC power supply according to the voltage across the electrolytic capacitor comprises:

S210: Collect a voltage across the electrolytic capacitor in a voltage cycle of the input AC power of the PFC power source, and store the voltage as a plurality of voltage sampling samples;

S220. Acquire a voltage sample sample having a maximum voltage value among the plurality of voltage sampling samples;

S230. Calculate a peak value of the input AC voltage of the PFC power source according to the voltage value of the voltage sample sample with the largest voltage value and the first preset calculation formula.

Preferably, the power factor correction circuit is a BOOST architecture, and the first preset calculation formula is:

Vac_peak = Vdc_peak + Vfrd + Vbd;

Where, Vac_peak is the input AC voltage peak of the PFC power supply, Vdc_peak is the maximum value of the voltage applied across the electrolytic capacitor, Vfrd is the conduction voltage drop of the fast recovery diode in the power factor correction circuit, and Vbd is the PFC power supply. The conduction voltage drop of the rectifier bridge.

Preferably, the power factor correction circuit includes a power switch tube and an inductor, and the determining the working mode of the power factor correction circuit specifically includes:

S310. Detect a voltage across the electrolytic capacitor to obtain a duty cycle of a switching period and an on-time of the power switch tube.

S320. Calculate a power factor correction circuit to work on a current threshold according to a voltage across the electrolytic capacitor, a switching period of the power switch tube, a duty ratio of an on-time of the power switch tube, and a second preset calculation formula. The current peak of the inductor when in mode;

S330. Detect a current current peak of the inductor.

S341, if the current current peak of the inductor is greater than a current peak of the inductor when the power factor correction circuit operates in a current critical mode, determining that the power factor correction circuit operates in a current continuous mode;

S342. If the current current peak of the inductor is equal to a current peak of the inductor when the power factor correction circuit operates in a current critical mode, determining that the power factor correction circuit operates in a current critical mode;

S343. Determine that the power factor correction circuit operates in a current discontinuous mode if a current current peak of the inductor is less than a current peak of the inductor when the power factor correction circuit operates in a current critical mode.

Preferably, the power factor correction circuit further includes a fast recovery diode, and the second preset calculation formula is:

Ipeak= (Vdc + Vfrd - Vigbt) / L × D(1-D) × Ts;

Where Ipeak is the current peak current of the inductor, and Vdc is the voltage across the electrolytic capacitor, Vfrd For the turn-on voltage drop of the fast recovery diode, Vigbt is the turn-on voltage drop of the power switch tube, L is the inductance value of the inductor, and D is the duty cycle of the power switch tube on-time, Ts The switching period of the power switch tube.

Preferably, the obtaining the instantaneous value of the input AC voltage of the PFC power supply according to the working mode of the power factor correction circuit specifically includes:

S351. When the power factor correction circuit operates in a current continuous mode or a current critical mode, acquire a current change amount of the inductor in one switching cycle of the power switch tube, and according to the current change amount and the third The preset calculation formula calculates the instantaneous value of the input AC voltage of the PFC power source;

S352. When the power factor correction circuit operates in the current interrupt mode, obtain an on time of the power switch tube in one switching cycle, and according to the turn-on time and the fourth pre-period of the power switch tube in one cycle. The calculation formula is used to calculate the instantaneous value of the input AC voltage of the PFC power supply.

Preferably, the PFC power supply further includes a rectifier bridge, the power factor correction circuit further includes a fast recovery diode, and the third preset calculation formula is:

Vac = Vdc × (1-D) + Vigbt × D + Vfrd × (1-D) + Vbd + L × ΔIin / Ts;

Wherein, Vac is the instantaneous value of the input AC voltage of the PFC power supply, Vdc is the voltage across the electrolytic capacitor, D is the duty ratio of the on-time of the power switch, and Vigbt is the conduction voltage drop of the power switch. Vfrd is the conduction voltage drop of the fast recovery diode, Vbd is the conduction voltage drop of the rectifier bridge, L is the inductance value of the inductor, and ΔIin is the inductance of the inductor in a switching cycle of the power switch tube The amount of current change, Ts is the switching period of the power switch tube.

Preferably, the PFC power supply further includes a rectifier bridge, and the fourth preset calculation formula is:

Vac = L × Ipeak / Ton + Vigbt + Vbd;

Where, Vac is the instantaneous value of the input AC voltage of the PFC power supply, L is the inductance value of the inductor, Ipeak is the current peak value of the inductor, and Ton is the opening time of the power switch tube in one switching cycle, and Vigb is the The conduction voltage drop of the power switch tube, Vbd is the conduction voltage drop of the rectifier bridge.

S510. Detect a voltage across the electrolytic capacitor to obtain a duty cycle of a switching period and an on-time of the power switch tube.

S520. Calculate a power factor correction circuit to work on a current threshold according to a voltage across the electrolytic capacitor, a switching period of the power switch tube, a duty ratio of an on-time of the power switch tube, and a fifth preset calculation formula. The midpoint value of the current of the inductor when in mode;

S530. Detect a current midpoint value of the inductor.

S541, if the current current midpoint value of the inductor is greater than a current midpoint value of the inductor when the power factor correction circuit operates in a current critical mode, determining that the power factor correction circuit operates in a current continuous mode;

S542, if the current current midpoint value of the inductor is equal to a current midpoint value of the inductor when the power factor correction circuit operates in a current critical mode, determining that the power factor correction circuit operates in a current critical mode;

S543. If the current current midpoint value of the inductor is less than a current midpoint value of the inductor when the power factor correction circuit operates in a current critical mode, determine that the power factor correction circuit operates in a current discontinuous mode.

Preferably, the power factor correction circuit further includes a fast recovery diode, and the fifth preset calculation formula is:

Imid = (Vdc + Vfrd - Vigbt) / L × D (1-D) × Ts/2;

Where Imid is the current current midpoint value of the inductor, and Vdc is the voltage across the electrolytic capacitor, Vfrd For the turn-on voltage drop of the fast recovery diode, Vigbt is the turn-on voltage drop of the power switch tube, L is the inductance value of the inductor, and D is the duty cycle of the power switch tube on-time, Ts The switching period of the power switch tube.

S551. When the power factor correction circuit operates in a current continuous mode or a current critical mode, obtain a current change amount of the inductor in one switching cycle of the power switch tube, and according to the current change amount and the sixth The preset calculation formula calculates the instantaneous value of the input AC voltage of the PFC power source;

S552. When the power factor correction circuit operates in the current interrupt mode, obtain an on time of the power switch tube in one switching cycle, and according to the turn-on time and the seventh pre-step of the power switch tube in one cycle. The calculation formula is used to calculate the instantaneous value of the input AC voltage of the PFC power supply.

Preferably, the PFC power supply further includes a rectifier bridge, and the power factor correction circuit further includes a fast recovery diode, and the sixth preset calculation formula is:

Vac = Vdc × (1-D) + Vigbt × D + Vfrd × (1-D) + Vbd + L × ΔIin / Ts;

Preferably, the PFC power supply further includes a rectifier bridge, and the seventh preset calculation formula is:

Vac = L × (Imid × 2) / Ton + Vigbt + Vbd;

Where, Vac is the instantaneous value of the input AC voltage of the PFC power supply, L is the inductance value of the inductor, Imid is the current midpoint value of the inductor, and Ton is the opening time of the power switch tube in one switching cycle, Vigbt For the conduction voltage drop of the power switch tube, Vbd is the conduction voltage drop of the rectifier bridge.

Preferably, the calculating an AC voltage effective value of the PFC power source according to the input AC voltage peak value or the input AC voltage instantaneous value is specifically:

Calculating an effective value of the AC voltage of the PFC power source according to the input AC voltage peak value and the eighth preset formula; or

Calculating an effective value of the AC voltage of the PFC power source according to the input AC voltage instantaneous value and the ninth preset formula;

The eighth preset formula is: Vac_rms = Vac_peak / sqrt(2);

The ninth preset formula is: Vac_rms = sqrt( LPF(Vac×Vac) );

Among them, Vac_rms is the AC voltage RMS value of the PFC power supply, Vac_peak is the AC voltage peak value of the power supply, sqrt(2) is the square root operation of the number "2", and Vac is the instantaneous value of the AC voltage of the power supply. LPF (Vac × Vac) is a low-pass filtering operation on (Vac × Vac), and sqrt ( LPF (Vac × Vac)) is a pair ( LPF (Vac × Vac) ) Perform an square root operation.

Preferably, the current operating parameters of the PFC power supply include:

At least one of a current power value of a load connected to the PFC power source, a current input current value of the PFC power source, and a current input current peak value of the PFC power source.

Preferably, the condition that the current operating parameter of the PFC power supply meets the power factor correction circuit of the PFC power supply is closed:

The current power value of the load connected to the PFC power source is less than the preset power value, or the current input current value of the PFC power source is less than the preset input current value, or the current input current peak value of the PFC power source is less than the preset input current peak value. ;

The current operating parameters of the PFC power supply satisfy the conditions for the power factor correction circuit of the PFC power supply to be turned on include:

The current power value of the load connected to the PFC power source is greater than or equal to the preset power value, or the current input current value of the PFC power source is greater than or equal to the preset input current value, or the current input current peak value of the PFC power source is greater than or equal to The preset input current peak.

Correspondingly, the present invention also provides an AC voltage RMS acquisition device for a PFC power supply, including:

a working parameter obtaining module, configured to acquire a current working parameter of the PFC power source;

a peak voltage acquisition module, configured to control a power factor correction circuit of the PFC power supply to be turned off when the current operating parameter of the PFC power supply meets a condition that the power factor correction circuit of the PFC power source is turned off, and obtain a voltage across the electrolytic capacitor of the PFC power supply, and then according to The voltage across the electrolytic capacitor acquires an input AC voltage peak of the PFC power supply;

The instantaneous voltage obtaining module is configured to control the power factor correction circuit to be turned on when the current operating parameter of the PFC power source meets the condition that the power factor correction circuit of the PFC power source is turned on, and determine the working mode of the power factor correction circuit, and then according to The working mode of the power factor correction circuit acquires an instantaneous value of the input AC voltage of the PFC power source;

The RMS calculation module is configured to calculate an RMS effective value of the PFC power source according to the input AC voltage peak value or the input AC voltage instantaneous value.

Preferably, the peak voltage acquisition module comprises:

a voltage collecting unit, configured to collect a voltage across the electrolytic capacitor in a voltage cycle of the input AC power of the PFC power source, and store the voltage as a plurality of voltage sampling samples;

a maximum voltage acquisition unit, configured to acquire a voltage sample sample having the largest voltage value among the plurality of voltage sample samples;

The peak voltage calculation unit calculates the input AC voltage peak value of the PFC power source according to the voltage value of the voltage sample sample with the largest voltage value and the first preset calculation formula.

Vac_peak= Vdc_peak + Vfrd + Vbd;

Preferably, the instantaneous voltage acquisition module comprises:

a first voltage detecting subunit for detecting a voltage across the electrolytic capacitor;

a first state acquiring subunit, configured to acquire a duty cycle of a switching period and an on time of the power switch tube;

a current peak calculating unit, configured to calculate a power factor correction according to a voltage across the electrolytic capacitor, a switching period of the power switch tube, a duty ratio of an on-time of the power switch tube, and a second preset calculation formula a current peak of the inductor when the circuit operates in a current critical mode;

a current peak detecting unit, configured to detect a current current peak of the inductor;

a first working mode determining unit, configured to determine that the power factor correction circuit operates in a current continuous mode when a current current peak of the inductor is greater than a current peak of the inductor when the power factor correction circuit operates in a current critical mode ;

Determining that the power factor correction circuit operates in a current critical mode when a current current peak of the inductor is equal to a current peak of the inductor when the power factor correction circuit operates in a current critical mode;

The power factor correction circuit is determined to operate in a current discontinuous mode when a current current peak of the inductor is less than a current peak of the inductor when the power factor correction circuit operates in a current critical mode.

Ipeak= (Vdc + Vfrd - Vigbt) / L × D(1-D) × Ts;

Preferably, the instantaneous voltage acquisition module further includes:

a first instantaneous voltage obtaining unit, configured to acquire, when the power factor correction circuit operates in a current continuous mode or a current critical mode, a current change amount of the inductor in one switching cycle of the power switch tube, and according to The current change amount and the third preset calculation formula acquire an instantaneous value of the input AC voltage of the PFC power source;

a second instantaneous voltage obtaining unit, configured to acquire an opening time of the power switch tube in one switching cycle when the power factor correction circuit operates in a current interrupt mode, and according to the power switch tube in one cycle The opening and the fourth preset calculation formula obtain the instantaneous value of the input AC voltage of the PFC power source.

Vac = Vdc × (1-D) + Vigbt × D + Vfrd × (1-D) + Vbd + L × ΔIin / Ts;

Vac = L × Ipeak / Ton + Vigbt + Vbd;

Preferably, the instantaneous voltage acquisition module comprises:

a second voltage detecting subunit for detecting a voltage across the electrolytic capacitor;

a second state acquiring subunit, configured to acquire a duty cycle of a switching period and an on time of the power switch tube;

a current midpoint value calculation unit, configured to calculate power according to a voltage across the electrolytic capacitor, a switching period of the power switch tube, a duty ratio of an on-time of the power switch tube, and a fifth preset calculation formula a current midpoint value of the inductor when the factor correction circuit operates in a current critical mode;

a current midpoint value detecting unit, configured to detect a current current midpoint value of the inductor;

a second working mode determining unit, configured to determine that the power factor correction circuit works when a current midpoint value of the inductor is greater than a current midpoint value of the inductor when the power factor correction circuit operates in a current critical mode In current continuous mode;

The current current midpoint value of the inductor is equal to a current midpoint value of the inductor when the power factor correction circuit operates in a current critical mode, and determining that the power factor correction circuit operates in a current critical mode;

The power factor correction circuit is determined to operate in a current discontinuous mode when a current midpoint value of the inductor is less than a current midpoint value of the inductor when the power factor correction circuit operates in a current critical mode.

Imid = (Vdc + Vfrd - Vigbt) / L × D (1-D) × Ts/2;

Preferably, the instantaneous voltage acquisition module further includes:

a third instantaneous voltage acquiring unit, configured to acquire a current change amount of the inductor in one switching cycle of the power switch tube when the power factor correction circuit operates in a current continuous mode or a current critical mode, and according to the The current variation amount and the sixth preset calculation formula obtain an instantaneous value of the input AC voltage of the PFC power source;

a fourth instantaneous voltage obtaining unit, configured to acquire an opening time of the power switch tube in one switching cycle when the power factor correction circuit operates in a current interrupt mode, and according to the power switch tube in one cycle The turn-on time and the seventh preset calculation formula obtain the instantaneous value of the input AC voltage of the PFC power source.

Vac = Vdc × (1-D) + Vigbt × D + Vfrd × (1-D) + Vbd + L × ΔIin / Ts;

Vac = L × (Imid × 2) / Ton + Vigbt + Vbd;

Preferably, the calculation module according to the effective value is specifically used to:

Calculating an AC voltage effective value of the PFC power source according to the input AC voltage peak value and an eighth preset formula; or calculating an AC voltage effective value of the PFC power source according to the input AC voltage instantaneous value and a ninth preset formula;

The eighth preset formula is Vac_rms = Vac_peak / sqrt(2);

The ninth preset formula is: Vac_rms = sqrt( LPF(Vac×Vac) );

Preferably, the current operating parameters of the PFC power supply include:

In the AC voltage RMS acquisition method of the PFC power supply: First, the current operating parameters of the PFC power supply are obtained. Then, if the current operating parameter of the PFC power supply satisfies the condition that the power factor correction circuit of the PFC power supply is turned off, the power factor correction circuit that controls the PFC power supply is turned off, and the peak value of the input AC voltage of the PFC power source is obtained according to the voltage across the electrolytic capacitor; When the current operating parameter of the PFC power supply meets the condition that the power factor correction circuit of the PFC power supply is turned on, the PFC power supply is turned on, and the instantaneous value of the input AC voltage of the PFC power source is obtained according to the working mode of the power factor correction circuit. Finally, the AC voltage rms value of the PFC power supply is calculated based on the input AC voltage peak or the input AC voltage instantaneous value. Since the technical solution acquires the instantaneous value of the input AC voltage of the PFC power source according to the working mode of the power factor correction circuit. Therefore, the technical solution can avoid the interference of the current interruption mode to the AC voltage RMS acquisition result of the PFC power supply, and the technical solution of the present invention has the characteristics of high accuracy compared with the prior art.

DRAWINGS

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the description of the prior art will be briefly described below. Obviously, the drawings in the following description are only It is a certain embodiment of the present invention, and those skilled in the art can obtain other drawings according to the structures shown in the drawings without any creative work.

1 is a schematic structural diagram of a circuit of an embodiment of a PFC power supply according to the present invention;

2 is a schematic flow chart of an embodiment of an AC voltage effective value acquisition method of a PFC power supply according to the present invention;

3 is a schematic diagram showing a refinement process of an embodiment of step S200 in FIG. 2;

4 is a schematic diagram showing the refinement process of an embodiment of step S300 in FIG. 2;

FIG. 5 is a schematic diagram showing a refinement process of another embodiment of step S300 in FIG. 2;

6 is a schematic diagram of functional modules of an embodiment of an AC voltage effective value obtaining apparatus for a PFC power supply according to the present invention;

7 is a schematic diagram of functional modules of an embodiment of the peak voltage acquisition module of FIG. 6;

8 is a schematic diagram of functional modules of an embodiment of the instantaneous voltage acquisition module of FIG. 6;

FIG. 9 is a schematic diagram of functional modules of another embodiment of the instantaneous voltage acquisition module of FIG. 6. FIG.

The implementation, functional features, and advantages of the present invention will be further described in conjunction with the embodiments.

Detailed ways

The technical solutions in the embodiments of the present invention are clearly and completely described in the following with reference to the accompanying drawings in the embodiments of the present invention. It is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts are within the scope of the present invention.

It is to be noted that the descriptions of "first", "second" and the like in the present invention are only for the purpose of description, and are not to be construed as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Thus, features defining "first" and "second" may include at least one of the features, either explicitly or implicitly. In addition, the technical solutions between the various embodiments may be combined with each other, but must be based on the realization of those skilled in the art, and when the combination of the technical solutions is contradictory or impossible to implement, it should be considered that the combination of the technical solutions does not exist. It is also within the scope of protection required by the present invention.

The invention provides a method for obtaining an RMS effective value of a PFC power source. Among them, the PFC power supply includes a power factor correction circuit, and the topology of the power factor correction circuit has various options, such as BOOST, BUCK, and the like.

In order to facilitate a better understanding of the technical solution of the present invention, the working principle of the PFC power supply is described in this embodiment by taking a BOOST power factor correction circuit as an example.

As shown in FIG. 1, the PFC power supply includes a rectifier bridge BD, an electrolytic capacitor C, and a BOOST type power factor correction circuit 10. The BOOST type power factor correction circuit 10 includes an inductor L, a power switch IGBT, a fast recovery diode FRD, and a controller. The input end of the rectifier bridge BD is used to connect the input AC power source AC, the positive end of the rectifier bridge BD is connected to the first end of the inductor L, the second end of the inductor L, the input end of the power switch tube IGBT and the fast recovery diode FRD The anode is interconnected, the cathode of the fast recovery diode FRD is connected to the anode of the electrolytic capacitor C, and the connection node is used to connect the positive pole of the load. The negative end of the rectifier bridge BD, the output end of the power switch tube IGBT and the negative pole of the electrolytic capacitor C are interconnected, and the connection node is used for connecting the negative pole of the load, and the controlled end of the power switch tube IGBT is connected with the control end of the controller.

The controller is configured to output a PWM wave to the controlled end of the power switch IGBT to enable the power factor correction circuit 10 to be turned on to implement a power factor correction function.

Specifically, when the power switch IGBT is turned on, current is output from the positive terminal of the rectifier bridge BD, and sequentially returned to the negative terminal of the rectifier bridge BD via the inductor L and the power switch IGBT. During this process, the inductor L current rises linearly and its voltage relationship satisfies:

Vac = L × p • Iin + Vigbt + Vbd ; (1)

When the power switch IGBT is turned off, the current is output from the positive terminal of the rectifier bridge BD, and sequentially returns to the negative terminal of the rectifier bridge BD via the inductor L, the fast recovery diode FRD, and the electrolytic capacitor C (and the load). In this process, when the output voltage of the rectifier bridge BD is higher than the voltage of the electrolytic capacitor C, the inductor L current continues to rise; when the output voltage of the rectifier bridge BD is lower than the voltage of the electrolytic capacitor C, the current of the inductor L decreases. Its voltage relationship satisfies:

Vac = Vdc + L × p • Iin + Vfrd + Vbd ; (2)

Among them, Vac Input the instantaneous value of the AC voltage (absolute value) for the PFC power supply, Vdc is the electrolytic capacitor C voltage, Iin is the instantaneous value of the inductor L current, p is the differential operator, L is the inductance value of the inductor L, and Vbd is the rectifier bridge BD conduction voltage Drop, Vigbt is the power switch tube IGBT turn-on voltage drop, Vfrd is the fast recovery diode FRD turn-on voltage drop.

Set the period of the PWM wave to Ts. During each PWM period, the power switch IGBT is turned on for Ton, the power switch IGBT is turned off for Toff, Ts=Ton+Toff, and the duty ratio is D=Ton. /Ts. It is assumed that the time during which the inductor L current rises is Tup during each PWM period, and the time at which the inductor L current decreases is Tfall. The sum of the rise and fall of the inductor L current during each PWM cycle is the final current change ΔIin, ie

(Vac-Vigbt–Vbd)×Tup +(Vac-Vdc-Vfrd–Vbd)×Tfall=L×ΔIin; (3)

When the power factor correction circuit 10 operates in the current continuous mode or the current critical mode and satisfies Ton=Tup, Toff=Tfall, then:

Vac=Vdc×(1-D)+Vigbt×D+Vfrd×(1-D)+Vbd+L×ΔIin/Ts ;(4)

When the power factor correction circuit 10 operates in the current interrupt mode, the inductor L current rises from zero in the current PWM period, and finally falls to zero, and the final current change ΔIin=0 satisfies Ton=Tup, Toff>Tfall, then :

Vac=Vdc×Tfall/(Ton+Tfall)+Vigbt×Ton/(Ton+Tfall)+Vfrd×Tfall/(Ton+Tfall)+Vbd ;(5)

Since the Tfall cannot be directly known when the power factor correction circuit 10 operates in the current chopping mode, the rms value of the AC voltage of the PFC power source cannot be directly obtained by the above equation (5). Because Toff>Tfall when the power factor correction circuit 10 operates in the current chopping mode, the effective value of the AC voltage calculated by using Toff instead of Tfall to be substituted into the above equation (5) will be larger than the actual value. This is the reason why the efficiencies of the AC voltage of the PFC power supply obtained by the prior art are too large.

However, when the power factor circuit 10 operates in the current chopping mode, the current peak Ipeak of the inductor L satisfies:

L×Ipeak = (Vac-Vigbt–Vbd)×Ton ;(6)

Therefore, the instantaneous value of the input AC voltage of the PFC power supply can be calculated according to the above formula (6). which is:

Vac=L×Ipeak/Ton+Vigbt+Vbd ;(7)

In addition, when the power factor correction circuit 10 operates in the current critical mode, the current peak value Ipeak of the inductor L satisfies:

Ipeak=(Vdc+Vfrd–Vigbt)/L×D(1-D)×Ts ;(8)

In one PWM period, the current peak value Ipeak of the inductor L is the current of the power switch tube IGBT from the turn-on to the turn-off time; the current midpoint value Imid of the inductor L is the current at the midpoint of the power switch IGBT turn-on.

When the power factor correction circuit 10 operates in the current interrupt mode or the current critical mode, the current peak value of the inductor L and the current midpoint value of the inductor L satisfy:

Ipeak=Imid×2 ;(9)

When the power factor correction circuit 10 operates in the current continuous mode, the current peak value of the inductor L and the current midpoint value of the inductor L satisfy:

Ipeak<(Imid×2) ;(10)

Based on the above description, referring to FIG. 2, in an embodiment, the AC voltage RMS acquisition method of the PFC power supply includes the following steps:

S100. Obtain a current working parameter of the PFC power supply.

Here, the current operating parameter of the PFC power supply may be the power value of the load connected to the PFC power supply; the input current value of the PFC power supply, or the input current peak of the PFC power supply; or the load connected to the PFC power supply. Any combination of the power value, the input current value of the PFC power supply, and the input current peak of the PFC power supply.

When the PFC power supply output power supplies power to the load, if the power factor correction circuit 10 is turned on, the PFC power supply outputs the corrected power supply to the load; if the power factor correction circuit 10 is turned off, the PFC power supply outputs the power supply without the power correction to the load. .

The load can be an actual electrical device, such as a motor, or an analog device for testing, such as a resistor.

In this embodiment, how to obtain the current operating parameters of the PFC power supply is described by taking an input current value of the PFC power supply as an example.

Specifically, the current path of the PFC power supply may be connected in series to detect a resistance (not shown), one end of which is grounded, and the other end is connected to the negative terminal of the rectifier bridge BD or the negative pole of the load. In this way, under the condition that the temperature, the current, and the like affect the resistance of the detecting resistor, the voltage detecting device (not shown) detects the voltage falling on the other end of the detecting resistor, and the input current of the PFC power source can be obtained. Also, when the other end of the sense resistor is connected to the negative terminal of the rectifier bridge BD, the detected voltage is a negative voltage; when the other end of the sense resistor is connected to the negative pole of the load, the detected voltage is a positive voltage. Preferably, the other end of the detection circuit is connected to the negative pole of the load. To broaden the selection range of the voltage detection device.

It is worth mentioning that, in the above manner, the input current peak of the PFC power supply can also be obtained.

S200. When the current operating parameter of the PFC power supply meets the condition that the power factor correction circuit 10 of the PFC power supply is turned off, the power factor correction circuit 10 that controls the PFC power supply is turned off, and the voltage across the electrolytic capacitor C of the PFC power supply is obtained, and then according to the electrolytic capacitor. The voltage across C is the peak value of the input AC voltage of the PFC power supply;

Here, the current operating parameter of the PFC power supply satisfies the condition that the power factor correction circuit 10 of the PFC power supply is turned off. Alternatively, the current operating parameter of the PFC power supply is smaller than the preset operating parameter. For example, the current power value of the load connected to the PFC power source is less than the preset power value, the current input current value of the PFC power source is less than the preset input current value, and the current input current peak value of the PFC power source is less than the preset input current peak value, etc. Etc., not listed here.

It should be noted that, in the PFC power supply, the meaning of setting the power factor correction circuit 10 is to reduce the transmission loss of the power supply. When the current operating parameters of the PFC power source (including the power value of the load connected to the PFC power source, the input current value of the PFC power source, the peak value of the input current of the PFC power source, etc.) are small, the transmission loss base of the power source is small, and the power factor correction circuit 10 The effect is relatively weak, and even the power consumption of the power factor correction circuit 10 itself is greater than the power transmission loss reduced by the power factor correction circuit 10. Therefore, the technical solution can select whether the power factor correction circuit 10 needs to be turned on according to the actual working state of the PFC power source, which not only facilitates the acquisition of the RMS value of the PFC power source, but also keeps the reactive power loss of the PFC power source at a relatively low level. status.

In addition, in this embodiment, in how to determine how the current operating parameter of the PFC power supply is less than the preset operating parameter, multiple manners may be employed.

For example, obtaining a current working parameter of the PFC power source; calculating a difference between a current working parameter of the PFC power source and a preset working parameter; if the difference is less than zero, determining that the current working parameter of the PFC power source is less than a preset working parameter. In this way, it can be quickly determined whether the current operating parameter of the PFC power supply is less than a preset operating parameter.

Or acquiring current working parameters of the PFC power supply; calculating a difference between the current working parameters of the PFC power supply and the preset working parameters; performing the above actions cyclically to obtain current working parameters and preset work of the plurality of calculated PFC power supplies The difference between the parameters; calculating an average of the plurality of differences; if the average of the plurality of differences is less than zero, determining that the current operating parameter of the PFC power source is less than the preset operating parameter. In this way, the influence of detection errors on the data acquisition result can be avoided, thereby improving reliability.

It is worth mentioning that if the operating parameter is the input current of the PFC power supply, the preset PFC power input current value can be selected from 1 amp to 2 amps.

Optionally, referring to FIG. 3, the voltage across the electrolytic capacitor C of the PFC power supply is obtained as follows, and the input AC voltage peak of the PFC power supply is obtained according to the voltage across the electrolytic capacitor C:

S210: Collect a voltage across the electrolytic capacitor C in a voltage cycle of the input AC power supply AC of the PFC power source, and store the voltage as a plurality of voltage sampling samples;

S220. Acquire a voltage sampling sample having the largest voltage value among the plurality of voltage sampling samples;

It can be understood that the more the sampled voltage samples are stored in one voltage cycle of the input AC power source AC of the PFC power source, the closer the voltage value of the voltage sample sample with the largest voltage value is to the peak value of the input AC voltage of the PFC power source. Preferably, in this embodiment, the stored voltage sample samples are between 50 and 100.

In addition, according to the working principle of the PFC power supply described above, when the power factor correction circuit 10 is turned off, the power switch tube IGBT is turned off, and the rectifier bridge BD, the inductor L, the fast recovery diode FRD, and the electrolytic capacitor C form a current loop, so that:

Vac_peak= Vdc_peak + Vfrd + Vbd;(11)

Among them, Vac_peak is the input AC voltage peak of the PFC power supply, and Vdc_peak is the maximum value of the voltage applied to the electrolytic capacitor C. The above formula (11) is the first preset calculation formula.

Since the above equation (11) is constant when the power factor correction circuit 10 is in the off state, and when the stored voltage sample is sufficiently large, the voltage value of the voltage sample having the largest voltage value, and the derivative of the fast recovery diode FRD The sum of the through voltage drop and the turn-on voltage drop of the rectifier bridge BD is almost equal to the peak value of the input AC voltage of the PFC power supply. Therefore, the present embodiment can obtain an accurate input AC voltage peak.

S300. When the current operating parameter of the PFC power supply meets the ON condition of the power factor correction circuit 10 of the PFC power supply, the control power factor correction circuit 10 is turned on, and determines an operation mode of the power factor correction circuit 10, and then according to the power factor correction circuit 10 The working mode acquires the instantaneous value of the input AC voltage of the PFC power source;

Here, the current operating parameter of the PFC power supply satisfies the condition that the power factor correction circuit 10 of the PFC power supply is turned on. The current working parameter of the PFC power supply is greater than or equal to the preset working parameter. For example, the current power value of the load connected to the PFC power source is greater than or equal to the preset power value, and the current input current value of the PFC power source is greater than or equal to the preset input current value, and the current input current peak value of the PFC power source is greater than or equal to the preset. The input current peaks, etc., are not listed here.

It should be noted that, in the PFC power supply, the meaning of setting the power factor correction circuit 10 is to reduce the transmission loss of the power supply. When the current operating parameters of the PFC power supply (including the power value of the load connected to the PFC power supply, the input current value of the PFC power supply, the peak value of the input current of the PFC power supply, etc.) are large, the transmission loss base of the power supply is large, and the power factor correction circuit is large. The role of 10 is relatively obvious. Therefore, the technical solution can select whether the power factor correction circuit 10 needs to be turned on according to the actual working state of the PFC power source, which not only facilitates the acquisition of the RMS value of the PFC power source, but also keeps the reactive power loss of the PFC power source at a relatively low level. status.

In addition, in this embodiment, various means are available on how to determine that the current operating parameter of the PFC power source is greater than or equal to the preset operating parameter.

For example, obtaining a current working parameter of the PFC power source; calculating a difference between a current working parameter of the PFC power source and a preset working parameter; if the difference is greater than or equal to zero, determining that a current working parameter of the PFC power source is greater than or equal to a preset working parameter. In this way, it can be quickly determined whether the current operating parameter of the PFC power supply is greater than or equal to the preset operating parameter.

Or acquiring current working parameters of the PFC power supply; calculating a difference between the current working parameters of the PFC power supply and the preset working parameters; performing the above actions cyclically to obtain current working parameters and preset work of the plurality of calculated PFC power supplies The difference of the parameters; calculating an average value of the plurality of differences; if the average of the plurality of differences is greater than or equal to zero, determining that the current operating parameter of the PFC power source is greater than or equal to the preset operating parameter. In this way, the influence of detection errors on the data acquisition result can be avoided, thereby improving reliability.

Optionally, referring to FIG. 4, the working mode of the power factor correction circuit is determined as follows, and then the instantaneous value of the input AC voltage of the PFC power source is obtained according to the working mode of the power factor correction circuit:

S310, detecting a voltage across the electrolytic capacitor C, and obtaining a duty cycle of a switching period and an on-time of the power switch IGBT;

The duty ratio of the on-time of the power switch IGBT refers to the duty ratio of the on-time of the power switch IGBT in one current switching cycle of the power switch IGBT.

It should be noted that, in a voltage cycle of the input power source AC of the PFC power source, the duty ratio of the on-time of the obtained power switch IGBT may be different at different times.

S320. Calculate the power factor correction circuit 10 when operating in the current critical mode according to the voltage across the electrolytic capacitor C, the switching period of the power switch IGBT, the duty ratio of the on-time of the power switch IGBT, and the second preset calculation formula. The peak current of the inductor;

According to the working principle of the PFC power supply, the second preset calculation formula can be selected as follows:

Ipeak= (Vdc + Vfrd - Vigbt) / L × D(1-D) × Ts; (12)

S330, detecting a current peak current of the inductor L;

The current peak value of the inductor L refers to the current value flowing through the inductor L when the power switch tube IGBT is switched from on to off at the current switching period of the power switch IGBT.

Preferably, a sampling resistor (not shown) can be added to assist in detecting the current of the load. For example, the first end of the sampling resistor is connected to the negative terminal of the rectifier bridge BD, and the second end of the sampling resistor, the output end of the power switching transistor IGBT, and the negative terminal of the electrolytic capacitor C are interconnected. Thus, under the condition that the resistance of the sampling resistor is known, the voltage falling on the second end of the sampling resistor can be detected, and the current of the PFC power supply, that is, the current flowing through the inductor L can be obtained.

S341. If the current peak value of the inductor L is greater than the current peak value of the inductor L when the power factor correction circuit 10 operates in the current critical mode, it is determined that the power factor correction circuit 10 operates in the current continuous mode;

It can be understood that in one switching cycle of the power switch IGBT: if the power factor correction circuit 10 operates in the current continuous mode, when the power switch IGBT is turned on, the current flowing through the inductor L is greater than zero, in the power switch When the tube IGBT is in the on state, the current flowing through the inductor L linearly increases. If the power factor correction circuit 10 operates in the current critical mode, the current flowing through the inductor L is equal to zero when the power switch IGBT is turned on, and the current flowing through the inductor L linearly increases when the power switch IGBT is turned on. .

Therefore, the current peak value of the inductance L when the power factor correction circuit 10 operates in the current continuous mode is greater than the current peak value of the inductance L when the power factor correction circuit 10 operates in the current critical mode. The technical solution has the characteristics of high accuracy.

S342. If the current peak value of the inductor L is equal to the current peak of the inductor L when the power factor correction circuit 10 operates in the current critical mode, it is determined that the power factor correction circuit 10 operates in the current critical mode;

S343. If the current peak value of the inductor L is less than the current peak value of the inductor L when the power factor correction circuit 10 operates in the current critical mode, it is determined that the power factor correction circuit 10 operates in the current discontinuous mode.

It can be understood that in one switching cycle of the power switch IGBT: if the power factor correction circuit 10 operates in the current interrupt mode, the current flowing through the inductor L is equal to zero before the power switch IGBT ends the off state. When the power switch IGBT is in the off state, the current flowing through the inductor L decreases linearly. If the power factor correction circuit 10 operates in the current critical mode, the current flowing through the inductor L is greater than zero before the power switch IGBT is turned off, and the current flowing through the inductor L when the power switch IGBT is in the off state. It decreases linearly.

Therefore, the current peak value of the inductance L when the power factor correction circuit 10 operates in the current critical mode is greater than the current peak value of the inductance L when the power factor correction circuit 10 operates in the current interruption mode. The technical solution has the characteristics of high accuracy.

S351. When the power factor correction circuit 10 operates in the current continuous mode or the current critical mode, obtain a current change amount of the inductor L in one switching cycle of the power switch tube IGBT, and calculate according to the current change amount and the third preset calculation formula. The instantaneous value of the input AC voltage of the PFC power supply;

Here, the third preset formula can be selected as:

Vac = Vdc × (1-D) + Vigbt × D + Vfrd × (1-D) + Vbd + L × ΔIin / Ts; (13)

S352: When the power factor correction circuit 10 operates in the current interrupt mode, obtain an on time of the power switch tube IGBT in one switching cycle, and according to a turn-on time and a fourth preset calculation formula of the power switch tube IGBT in one cycle Calculate the instantaneous value of the input AC voltage of the PFC power supply.

Here, the fourth preset formula can be selected as:

Vac = L × Ipeak / Ton + Vigbt + Vbd; (14)

The technical solution determines the operating mode of the power factor correction circuit 10 according to the current peak value of the inductor L, and selects different calculation formulas for different operating modes of the power factor correction circuit 10 to calculate the instantaneous value of the input AC voltage of the PFC power supply. In this embodiment, the mode of determining the operating mode of the power factor correction circuit 10 is reliable, and the result of calculating the instantaneous value of the input AC voltage of the PFC power source is accurate.

Optionally, referring to FIG. 5, the working mode of the power factor correction circuit is determined as follows, and then the instantaneous value of the input AC voltage of the PFC power source is obtained according to the working mode of the power factor correction circuit:

S510, detecting a voltage across the electrolytic capacitor C, and obtaining a duty cycle of a switching period and an on-time of the power switch IGBT;

S520. Calculate the power factor correction circuit 10 to work in the current critical mode according to the voltage of the two ends C of the electrolytic capacitor, the switching period of the power switch tube IGBT, the duty ratio of the on-time of the power switch tube IGBT, and the fifth preset calculation formula. The current midpoint value of the inductor L;

According to the working principle of the PFC power supply described above, the fifth preset calculation formula can be selected as follows:

Imid = (Vdc + Vfrd – Vigbt) / L × D(1-D) × Ts/2 ;(15)

Where Imid is the current midpoint value of the inductor L when the power factor correction circuit 10 operates in the current critical mode.

S530. Detect a current midpoint value of the inductor L.

Wherein, the current current midpoint value of the inductor L refers to the current value flowing through the inductor L at the midpoint of the power switch IGBT turning on at the current switching cycle of the power switch IGBT.

S541, if the current current midpoint value of the inductor L is greater than the current midpoint value of the inductor L when the power factor correction circuit 10 operates in the current critical mode, determining that the power factor correction circuit 10 operates in the current continuous mode;

Therefore, the current midpoint value of the inductor L when the power factor correction circuit 10 operates in the current continuous mode is greater than the current midpoint value of the inductor L when the power factor correction circuit 10 operates in the current critical mode. The technical solution has the characteristics of high accuracy.

S542. If the current current midpoint value of the inductor is equal to the current midpoint value of the inductor when the power factor correction circuit operates in the current critical mode, determine that the power factor correction circuit operates in the current critical mode;

S543. If the current current midpoint value of the inductor is less than a current midpoint value of the inductor when the power factor correction circuit operates in the current critical mode, determine that the power factor correction circuit operates in the current discontinuous mode.

Therefore, the current peak value of the inductance L when the power factor correction circuit 10 operates in the current critical mode is greater than the current peak value of the inductance L when the power factor correction circuit 10 operates in the current interruption mode.

When the power factor correction circuit 10 operates in the current critical mode or the current discontinuous mode, the current peak of the inductor L is twice the midpoint of the inductor L current. Therefore, when the power factor correction circuit 10 operates in the current critical mode, the current midpoint value of the inductor L is greater than the current midpoint value of the inductor L when the power factor correction circuit 10 operates in the current discontinuous mode. The technical solution has the characteristics of high accuracy.

S551. When the power factor correction circuit 10 operates in the current continuous mode or the current critical mode, obtain a current change amount of the inductor L in one switching cycle of the power switch tube IGBT, and calculate according to the current change amount and the sixth preset calculation formula. The instantaneous value of the input AC voltage of the PFC power supply;

Here, the sixth preset formula can be selected as:

Vac = Vdc × (1-D) + Vigbt × D + Vfrd × (1-D) + Vbd + L × ΔIin / Ts; (16)

S552. When the power factor correction circuit 10 operates in the current discontinuous mode, obtain an on-time of the power switch IGBT in one switching cycle, and according to a turn-on time and a seventh preset calculation formula of the power switch IGBT in one cycle Calculate the instantaneous value of the input AC voltage of the PFC power supply.

Here, the seventh preset formula can be selected as:

Vac = L × (Imid × 2) / Ton + Vigbt + Vbd; (17)

The technical solution determines the operating mode of the power factor correction circuit 10 according to the current midpoint value of the inductor L, and selects different calculation formulas for different operating modes of the power factor correction circuit 10 to calculate the instantaneous value of the input AC voltage of the PFC power supply. In this embodiment, the mode of determining the operating mode of the power factor correction circuit 10 is reliable, and the result of calculating the instantaneous value of the input AC voltage of the PFC power source is accurate.

S400: Calculate an RMS effective value of the PFC power source according to the input AC voltage peak value or the input AC voltage instantaneous value.

Specifically, the AC voltage effective value of the PFC power source is calculated according to the input AC voltage peak value and the eighth preset formula; or the AC voltage effective value of the PFC power source is calculated according to the input AC voltage instantaneous value and the ninth preset formula.

Here, the eighth preset formula is: Vac_rms = Vac_peak / sqrt(2); (18)

The ninth preset formula is: Vac_rms = sqrt( LPF(Vac×Vac) ); (19)

In the AC voltage RMS acquisition method of the PFC power supply: First, the current operating parameters of the PFC power supply are obtained. Then, if the current operating parameter of the PFC power supply satisfies the condition that the power factor correction circuit 10 of the PFC power supply is turned off, the power factor correction circuit 10 that controls the PFC power supply is turned off, and the input AC voltage of the PFC power source is obtained according to the voltage across the electrolytic capacitor C. If the current operating parameter of the PFC power supply satisfies the condition that the power factor correction circuit 10 of the PFC power supply is turned on, the PFC power supply is turned on, and the instantaneous value of the input AC voltage of the PFC power source is obtained according to the operation mode of the power factor correction circuit 10. Finally, the AC voltage rms value of the PFC power supply is calculated based on the input AC voltage peak or the input AC voltage instantaneous value. Since the technical solution acquires the instantaneous value of the input AC voltage of the PFC power source according to the working mode of the power factor correction circuit. Therefore, the technical solution can avoid the interference of the current interruption mode to the AC voltage RMS acquisition result of the PFC power supply, and the technical solution of the present invention has the characteristics of high accuracy compared with the prior art.

Correspondingly, the present invention also provides an input AC voltage RMS acquisition device for a PFC power supply. Please refer to FIG. 6. Referring to FIG. 6, in an embodiment, the apparatus includes:

The working parameter obtaining module 100 is configured to acquire current working parameters of the PFC power source;

The peak voltage acquisition module 200 is configured to control the power factor correction circuit 10 of the PFC power supply to be turned off when the current operating parameter of the PFC power supply meets the condition that the power factor correction circuit 10 of the PFC power supply is turned off, and acquire the two ends of the electrolytic capacitor C of the PFC power supply. Voltage, and then according to the voltage across the electrolytic capacitor C to obtain the input AC voltage peak of the PFC power supply;

Optionally, referring to FIG. 7, in an embodiment, the peak voltage acquisition module 200 includes:

The voltage collecting unit 210 is configured to collect a voltage across the electrolytic capacitor in a voltage cycle of the input AC power of the PFC power source, and store the voltage as a plurality of voltage sampling samples;

The maximum voltage acquiring unit 220 is configured to acquire a voltage sampling sample having the largest voltage value among the plurality of voltage sampling samples;

The peak voltage calculation unit 230 calculates the input AC voltage peak value of the PFC power source according to the voltage value of the voltage sample sample having the largest voltage value and the first preset calculation formula.

Vac_peak= Vdc_peak + Vfrd + Vbd;(20)

Among them, Vac_peak is the input AC voltage peak of the PFC power supply, and Vdc_peak is the maximum value of the voltage applied to the electrolytic capacitor C. The above formula (20) is the first preset calculation formula.

Since the above equation (20) is constant when the power factor correction circuit 10 is in the off state, and when the stored voltage sample samples are sufficiently large, the voltage value of the voltage sample having the largest voltage value, and the guide of the fast recovery diode FRD The sum of the through voltage drop and the turn-on voltage drop of the rectifier bridge BD is almost equal to the peak value of the input AC voltage of the PFC power supply. Therefore, the present embodiment can obtain an accurate input AC voltage peak.

The instantaneous voltage acquisition module 300 is configured to control the power factor correction circuit 10 to be turned on when the current operating parameter of the PFC power supply meets the ON condition of the power factor correction circuit 10 of the PFC power supply, and determine the operation mode of the power factor correction circuit 10, and then according to The working mode of the power factor correction circuit 10 acquires an instantaneous value of the input AC voltage of the PFC power source;

Optionally, referring to FIG. 8, in another embodiment, the instantaneous voltage obtaining module 300 includes:

The first voltage detecting subunit 311 is configured to detect a voltage across the electrolytic capacitor;

a first state acquisition sub-unit 312, configured to acquire a duty cycle of a switching period and an on-time of the power switch tube;

The current peak calculating unit 320 is configured to calculate the power factor correction circuit to work on the current threshold according to the voltage across the electrolytic capacitor, the switching period of the power switch tube, the duty ratio of the on-time of the power switch tube, and the second preset calculation formula. The current peak of the inductor in mode;

Ipeak= (Vdc + Vfrd - Vigbt) / L × D(1-D) × Ts; (21)

The current peak detecting unit 330 is configured to detect a current peak current of the inductor;

The first working mode determining unit 340 is configured to determine that the power factor correction circuit operates in the current continuous mode when the current current peak of the inductor is greater than a current peak of the inductor when the power factor correction circuit operates in the current critical mode;

Determining that the power factor correction circuit operates in the current critical mode when the current current peak of the inductor is equal to the current peak of the inductor when the power factor correction circuit operates in the current critical mode;

When the current current peak of the inductor is less than the current peak value of the inductor when the power factor correction circuit operates in the current critical mode, it is determined that the power factor correction circuit operates in the current discontinuous mode.

Therefore, the current peak value of the inductance L when the power factor correction circuit 10 operates in the current continuous mode is greater than the current peak value of the inductance L when the power factor correction circuit 10 operates in the current critical mode.

During one switching cycle of the power switch IGBT: if the power factor correction circuit 10 operates in the current interrupt mode, the current flowing through the inductor L is equal to zero before the power switch IGBT is turned off, and the IGBT is at the power switch In the off state, the current flowing through the inductor L decreases linearly. If the power factor correction circuit 10 operates in the current critical mode, the current flowing through the inductor L is greater than zero before the power switch IGBT is turned off, and the current flowing through the inductor L when the power switch IGBT is in the off state. It decreases linearly.

The technical solution has the characteristics of high accuracy.

The first instantaneous voltage obtaining unit 351 is configured to acquire a current change amount of the inductor in one switching cycle of the power switch tube when the power factor correction circuit operates in the current continuous mode or the current critical mode, and according to the current change amount and the first The three preset calculation formulas obtain the instantaneous value of the input AC voltage of the PFC power source;

Here, the third preset formula can be selected as:

Vac = Vdc × (1-D) + Vigbt × D + Vfrd × (1-D) + Vbd + L × ΔIin / Ts; (22)

The second instantaneous voltage obtaining unit 352 is configured to obtain an opening time of the power switch tube in one switching cycle when the power factor correction circuit operates in the current interrupt mode, and open and fourth according to the power switch tube in one cycle The preset calculation formula obtains the instantaneous value of the input AC voltage of the PFC power supply.

Here, the fourth preset formula can be selected as:

Vac = L × Ipeak / Ton + Vigbt + Vbd; (23)

Optionally, referring to FIG. 9, in another embodiment, the instantaneous voltage obtaining module 300 includes:

a second voltage detecting subunit 511 for detecting a voltage across the electrolytic capacitor;

a second state acquiring sub-unit 512, configured to acquire a duty cycle of a switching period and an on-time of the power switch tube;

The current midpoint value calculation unit 520 is configured to calculate the power factor correction circuit according to the voltage across the electrolytic capacitor, the switching period of the power switch tube, the duty ratio of the on-time of the power switch tube, and the fifth preset calculation formula. The midpoint value of the current of the inductor in the current critical mode;

Imid = (Vdc + Vfrd - Vigbt) / L × D (1-D) × Ts / 2; (24)

The current midpoint value detecting unit 530 is configured to detect a current current midpoint value of the inductor;

The second working mode determining unit 540 is configured to determine that the power factor correction circuit operates in the current continuous mode when the current current midpoint value of the inductor is greater than a current midpoint value of the inductor when the power factor correction circuit operates in the current critical mode;

The current current midpoint value of the inductor is equal to the current midpoint value of the inductor when the power factor correction circuit operates in the current critical mode, and the power factor correction circuit is determined to operate in the current critical mode;

The current midpoint value of the inductor is less than the current midpoint value of the inductor when the power factor correction circuit operates in the current critical mode, and the power factor correction circuit is determined to operate in the current discontinuous mode.

Therefore, the current midpoint value of the inductor L when the power factor correction circuit 10 operates in the current continuous mode is greater than the current midpoint value of the inductor L when the power factor correction circuit 10 operates in the current critical mode.

When the power factor correction circuit 10 operates in the current critical mode or the current discontinuous mode, the current peak of the inductor L is twice the midpoint of the inductor L current. Therefore, when the power factor correction circuit 10 operates in the current critical mode, the current midpoint value of the inductor L is greater than the current midpoint value of the inductor L when the power factor correction circuit 10 operates in the current discontinuous mode.

The technical solution has the characteristics of high accuracy.

The third instantaneous voltage obtaining unit 551 is configured to obtain, when the power factor correction circuit operates in the current continuous mode or the current critical mode, acquire a current change amount of the inductor in one switching cycle of the power switch tube, and according to the current change amount and the sixth The preset calculation formula obtains an instantaneous value of the input AC voltage of the PFC power source;

Here, the sixth preset formula can be selected as:

Vac = Vdc × (1-D) + Vigbt × D + Vfrd × (1-D) + Vbd + L × ΔIin / Ts; (25)

The fourth instantaneous voltage obtaining unit 552 is configured to obtain an opening time of the power switch tube in one switching period when the power factor correction circuit operates in the current interrupt mode, and according to the opening time and the first time of the power switch tube in one cycle Seven preset calculation formulas obtain the instantaneous value of the input AC voltage of the PFC power supply.

Here, the seventh preset formula can be selected as:

Vac = L × (Imid × 2) / Ton + Vigbt + Vbd; (26)

The RMS calculation module 400 is configured to calculate an RMS effective value of the PFC power source according to the input AC voltage peak value or the input AC voltage instantaneous value.

Here, the eighth preset formula is: Vac_rms = Vac_peak / sqrt(2); (27)

The ninth preset formula is: Vac_rms = sqrt( LPF(Vac×Vac) ); (28)

In the AC voltage RMS acquisition device of the PFC power supply: First, the operation parameter acquisition module 100 acquires the current operating parameters of the PFC power supply. Then, the peak voltage acquisition module 200 controls the power factor correction circuit 10 of the PFC power supply to be turned off under the condition that the current operating parameter of the PFC power supply meets the power factor correction circuit 10 of the PFC power supply, and the PFC power supply is obtained according to the voltage across the electrolytic capacitor C. The input AC voltage peak value; the instantaneous voltage acquisition module 300 controls the PFC power supply to be turned on when the current operating parameter of the PFC power supply meets the condition that the power factor correction circuit 10 of the PFC power supply is turned on, and acquires the PFC power supply according to the operation mode of the power factor correction circuit 10 The instantaneous value of the input AC voltage. Finally, the effective value calculation module 400 calculates an AC voltage effective value of the PFC power source according to the input AC voltage peak value or the input AC voltage instantaneous value. Since the technical solution acquires the instantaneous value of the input AC voltage of the PFC power source according to the working mode of the power factor correction circuit. Therefore, the technical solution can avoid the interference of the current interruption mode to the AC voltage RMS acquisition result of the PFC power supply, and the technical solution of the present invention has the characteristics of high accuracy compared with the prior art.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the invention, and the equivalent structural transformation, or direct/indirect use, of the present invention and the contents of the drawings are used in the inventive concept of the present invention. It is included in the scope of the patent protection of the present invention in other related technical fields.

Claims

A method for obtaining an AC voltage RMS value of a PFC power supply, characterized in that the method comprises the following steps:

S100. Obtain a current working parameter of the PFC power supply.

S200. When the current operating parameter of the PFC power supply meets the condition that the power factor correction circuit of the PFC power supply is turned off, the power factor correction circuit that controls the PFC power supply is turned off, and the voltage across the electrolytic capacitor of the PFC power supply is obtained, and then according to the electrolysis. The voltage across the capacitor acquires the peak value of the input AC voltage of the PFC power supply;

S300. When the current operating parameter of the PFC power supply meets a condition that the power factor correction circuit of the PFC power supply is turned on, control the power factor correction circuit to be turned on, and determine an operation mode of the power factor correction circuit, and then according to the power. The working mode of the factor correction circuit acquires an instantaneous value of the input AC voltage of the PFC power source;

S400. Calculate an RMS effective value of the PFC power source according to the input AC voltage peak value or the input AC voltage instantaneous value.
The method for obtaining an AC voltage RMS value of a PFC power supply according to claim 1, wherein the voltage across the electrolytic capacitor of the PFC power source is obtained, and then the input AC voltage peak of the PFC power source is obtained according to the voltage across the electrolytic capacitor. Specifically include:

S210: Collect a voltage across the electrolytic capacitor in a voltage cycle of the input AC power of the PFC power source, and store the voltage as a plurality of voltage sampling samples;

S220. Acquire a voltage sample sample having a maximum voltage value among the plurality of voltage sampling samples;

S230. Calculate a peak value of the input AC voltage of the PFC power source according to the voltage value of the voltage sample sample with the largest voltage value and the first preset calculation formula.
The AC voltage RMS acquisition method of the PFC power supply of claim 2, wherein the power factor correction circuit is a BOOST architecture, and the first preset calculation formula is:

Vac_peak = Vdc_peak + Vfrd + Vbd;

Where, Vac_peak is the input AC voltage peak of the PFC power supply, Vdc_peak is the maximum value of the voltage applied across the electrolytic capacitor, Vfrd is the conduction voltage drop of the fast recovery diode in the power factor correction circuit, and Vbd is the PFC power supply. The conduction voltage drop of the rectifier bridge.
The AC voltage RMS acquisition method of the PFC power supply of claim 1 , wherein the power factor correction circuit comprises a power switch and an inductor, and the determining the working mode of the power factor correction circuit comprises:

S310. Detect a voltage across the electrolytic capacitor to obtain a duty cycle of a switching period and an on-time of the power switch tube.

S320. Calculate a power factor correction circuit to work on a current threshold according to a voltage across the electrolytic capacitor, a switching period of the power switch tube, a duty ratio of an on-time of the power switch tube, and a second preset calculation formula. The current peak of the inductor when in mode;

S330. Detect a current current peak of the inductor.

S341, if the current current peak of the inductor is greater than a current peak of the inductor when the power factor correction circuit operates in a current critical mode, determining that the power factor correction circuit operates in a current continuous mode;

S342. If the current current peak of the inductor is equal to a current peak of the inductor when the power factor correction circuit operates in a current critical mode, determining that the power factor correction circuit operates in a current critical mode;

S343. Determine that the power factor correction circuit operates in a current discontinuous mode if a current current peak of the inductor is less than a current peak of the inductor when the power factor correction circuit operates in a current critical mode.
The AC voltage RMS acquisition method of the PFC power supply of claim 4, wherein the power factor correction circuit further comprises a fast recovery diode, and the second preset calculation formula is:

Ipeak= (Vdc + Vfrd - Vigbt) / L × D (1-D) × Ts;

Where Ipeak is the current peak current of the inductor, and Vdc is the voltage across the electrolytic capacitor, Vfrd For the turn-on voltage drop of the fast recovery diode, Vigbt is the turn-on voltage drop of the power switch tube, L is the inductance value of the inductor, and D is the duty cycle of the power switch tube on-time, Ts The switching period of the power switch tube.
The AC voltage RMS acquisition method of the PFC power supply according to claim 4, wherein the obtaining the instantaneous value of the input AC voltage of the PFC power supply according to the operating mode of the power factor correction circuit comprises:

S351. When the power factor correction circuit operates in a current continuous mode or a current critical mode, acquire a current change amount of the inductor in one switching cycle of the power switch tube, and according to the current change amount and the third The preset calculation formula calculates the instantaneous value of the input AC voltage of the PFC power source;

S352. When the power factor correction circuit operates in the current interrupt mode, obtain an on time of the power switch tube in one switching cycle, and according to the turn-on time and the fourth pre-period of the power switch tube in one cycle. The calculation formula is used to calculate the instantaneous value of the input AC voltage of the PFC power supply.
The AC voltage RMS acquisition method of the PFC power supply of claim 6, wherein the PFC power supply further comprises a rectifier bridge, the power factor correction circuit further comprises a fast recovery diode, and the third preset calculation formula for:

Vac = Vdc × (1-D) + Vigbt × D + Vfrd × (1-D) + Vbd + L × ΔIin / Ts;

Wherein, Vac is the instantaneous value of the input AC voltage of the PFC power supply, Vdc is the voltage across the electrolytic capacitor, D is the duty ratio of the on-time of the power switch, and Vigbt is the conduction voltage drop of the power switch. Vfrd is the conduction voltage drop of the fast recovery diode, Vbd is the conduction voltage drop of the rectifier bridge, L is the inductance value of the inductor, and ΔIin is the inductance of the inductor in a switching cycle of the power switch tube The amount of current change, Ts is the switching period of the power switch tube.
The AC voltage RMS acquisition method of the PFC power supply of claim 6, wherein the PFC power supply further comprises a rectifier bridge, and the fourth preset calculation formula is:

Vac = L × Ipeak / Ton + Vigbt + Vbd;

Where, Vac is the instantaneous value of the input AC voltage of the PFC power supply, L is the inductance value of the inductor, Ipeak is the current peak value of the inductor, and Ton is the opening time of the power switch tube in one switching cycle, and Vigb is the The conduction voltage drop of the power switch tube, Vbd is the conduction voltage drop of the rectifier bridge.
The AC voltage RMS acquisition method of the PFC power supply of claim 1 , wherein the power factor correction circuit comprises a power switch and an inductor, and the determining the working mode of the power factor correction circuit comprises:

S510. Detect a voltage across the electrolytic capacitor to obtain a duty cycle of a switching period and an on-time of the power switch tube.

S520. Calculate a power factor correction circuit to work on a current threshold according to a voltage across the electrolytic capacitor, a switching period of the power switch tube, a duty ratio of an on-time of the power switch tube, and a fifth preset calculation formula. The midpoint value of the current of the inductor when in mode;

S530. Detect a current midpoint value of the inductor.

S541, if the current current midpoint value of the inductor is greater than a current midpoint value of the inductor when the power factor correction circuit operates in a current critical mode, determining that the power factor correction circuit operates in a current continuous mode;

S542, if the current current midpoint value of the inductor is equal to a current midpoint value of the inductor when the power factor correction circuit operates in a current critical mode, determining that the power factor correction circuit operates in a current critical mode;

S543. If the current current midpoint value of the inductor is less than a current midpoint value of the inductor when the power factor correction circuit operates in a current critical mode, determine that the power factor correction circuit operates in a current discontinuous mode.
The AC voltage RMS acquisition method of the PFC power supply according to claim 9, wherein the power factor correction circuit further comprises a fast recovery diode, and the fifth preset calculation formula is:

Imid = (Vdc + Vfrd - Vigbt) / L × D (1-D) × Ts/2;

Where Imid is the current current midpoint value of the inductor, and Vdc is the voltage across the electrolytic capacitor, Vfrd For the turn-on voltage drop of the fast recovery diode, Vigbt is the turn-on voltage drop of the power switch tube, L is the inductance value of the inductor, and D is the duty cycle of the power switch tube on-time, Ts The switching period of the power switch tube.
The method for obtaining an AC voltage RMS value of a PFC power supply according to claim 9, wherein the obtaining an instantaneous value of the input AC voltage of the PFC power supply according to the operating mode of the power factor correction circuit comprises:

S551. When the power factor correction circuit operates in a current continuous mode or a current critical mode, obtain a current change amount of the inductor in one switching cycle of the power switch tube, and according to the current change amount and the sixth The preset calculation formula calculates the instantaneous value of the input AC voltage of the PFC power source;

S552. When the power factor correction circuit operates in the current interrupt mode, obtain an on time of the power switch tube in one switching cycle, and according to the turn-on time and the seventh pre-step of the power switch tube in one cycle. The calculation formula is used to calculate the instantaneous value of the input AC voltage of the PFC power supply.
The AC voltage RMS acquisition method of the PFC power supply according to claim 11, wherein the PFC power supply further comprises a rectifier bridge, the power factor correction circuit further comprises a fast recovery diode, and the sixth preset calculation formula for:

Vac = Vdc × (1-D) + Vigbt × D + Vfrd × (1-D) + Vbd + L × ΔIin / Ts;

Wherein, Vac is the instantaneous value of the input AC voltage of the PFC power supply, Vdc is the voltage across the electrolytic capacitor, D is the duty ratio of the on-time of the power switch, and Vigbt is the conduction voltage drop of the power switch. Vfrd is the conduction voltage drop of the fast recovery diode, Vbd is the conduction voltage drop of the rectifier bridge, L is the inductance value of the inductor, and ΔIin is the inductance of the inductor in a switching cycle of the power switch tube The amount of current change, Ts is the switching period of the power switch tube.
The AC voltage RMS acquisition method of the PFC power supply of claim 11, wherein the PFC power supply further comprises a rectifier bridge, and the seventh preset calculation formula is:

Vac = L × (Imid × 2) / Ton + Vigbt + Vbd;

Where, Vac is the instantaneous value of the input AC voltage of the PFC power supply, L is the inductance value of the inductor, Imid is the current midpoint value of the inductor, and Ton is the opening time of the power switch tube in one switching cycle, Vigbt For the conduction voltage drop of the power switch tube, Vbd is the conduction voltage drop of the rectifier bridge.
The method for obtaining an AC voltage RMS value of a PFC power supply according to claim 1, wherein the calculating an AC voltage effective value of the PFC power source according to the input AC voltage peak value or the input AC voltage instantaneous value is specifically:

Calculating an effective value of the AC voltage of the PFC power source according to the input AC voltage peak value and the eighth preset formula; or

Calculating an effective value of the AC voltage of the PFC power source according to the input AC voltage instantaneous value and the ninth preset formula;

The eighth preset formula is: Vac_rms = Vac_peak / sqrt(2);

The ninth preset formula is: Vac_rms = sqrt( LPF(Vac×Vac) );

Among them, Vac_rms is the AC voltage RMS value of the PFC power supply, Vac_peak is the AC voltage peak value of the power supply, sqrt(2) is the square root operation of the number "2", and Vac is the instantaneous value of the AC voltage of the power supply. LPF (Vac × Vac) is a low-pass filtering operation on (Vac × Vac), and sqrt ( LPF (Vac × Vac)) is a pair ( LPF (Vac × Vac) ) Perform an square root operation.
The method for obtaining an AC voltage RMS value of a PFC power supply according to claim 1, wherein the current operating parameters of the PFC power source include:

At least one of a current power value of a load connected to the PFC power source, a current input current value of the PFC power source, and a current input current peak value of the PFC power source.
The AC voltage RMS acquisition method of the PFC power supply according to claim 15, wherein

The current operating parameters of the PFC power supply satisfy the conditions for the power factor correction circuit of the PFC power supply to be turned off, including:

The current power value of the load connected to the PFC power source is less than the preset power value, or the current input current value of the PFC power source is less than the preset input current value, or the current input current peak value of the PFC power source is less than the preset input current peak value. ;

The current operating parameters of the PFC power supply satisfy the conditions for the power factor correction circuit of the PFC power supply to be turned on include:

The current power value of the load connected to the PFC power source is greater than or equal to the preset power value, or the current input current value of the PFC power source is greater than or equal to the preset input current value, or the current input current peak value of the PFC power source is greater than or equal to The preset input current peak.
An AC voltage RMS acquisition device for a PFC power supply, comprising:

a working parameter obtaining module, configured to acquire a current working parameter of the PFC power source;

a peak voltage acquisition module, configured to control a power factor correction circuit of the PFC power supply to be turned off when the current operating parameter of the PFC power supply meets a condition that the power factor correction circuit of the PFC power source is turned off, and obtain a voltage across the electrolytic capacitor of the PFC power supply, and then according to The voltage across the electrolytic capacitor acquires an input AC voltage peak of the PFC power supply;

The instantaneous voltage acquisition module is configured to control the power factor correction circuit to be turned on when the current operating parameter of the PFC power supply meets a condition that the power factor correction circuit of the PFC power source is turned on, and determine an operation mode of the power factor correction circuit, And then acquiring an instantaneous value of the input AC voltage of the PFC power source according to the working mode of the power factor correction circuit;

The RMS calculation module is configured to calculate an RMS effective value of the PFC power source according to the input AC voltage peak value or the input AC voltage instantaneous value.
The AC voltage RMS acquisition device of the PFC power supply of claim 17, wherein the peak voltage acquisition module comprises:

a voltage collecting unit, configured to collect a voltage across the electrolytic capacitor in a voltage cycle of the input AC power of the PFC power source, and store the voltage as a plurality of voltage sampling samples;

a maximum voltage acquisition unit, configured to acquire a voltage sample sample having the largest voltage value among the plurality of voltage sample samples;

The peak voltage calculation unit calculates the input AC voltage peak value of the PFC power source according to the voltage value of the voltage sample sample with the largest voltage value and the first preset calculation formula.
The AC voltage RMS acquisition device of the PFC power supply of claim 18, wherein the power factor correction circuit is a BOOST architecture, and the first preset calculation formula is:

Vac_peak= Vdc_peak + Vfrd + Vbd;

Where, Vac_peak is the input AC voltage peak of the PFC power supply, Vdc_peak is the maximum value of the voltage applied across the electrolytic capacitor, Vfrd is the conduction voltage drop of the fast recovery diode in the power factor correction circuit, and Vbd is the PFC power supply. The conduction voltage drop of the rectifier bridge.
The AC voltage RMS acquisition device of the PFC power supply of claim 17, wherein the instantaneous voltage acquisition module comprises:

a first voltage detecting subunit for detecting a voltage across the electrolytic capacitor;

a first state acquiring subunit, configured to acquire a duty cycle of a switching period and an on time of the power switch tube;

a current peak calculating unit, configured to calculate a power factor correction according to a voltage across the electrolytic capacitor, a switching period of the power switch tube, a duty ratio of an on-time of the power switch tube, and a second preset calculation formula a current peak of the inductor when the circuit operates in a current critical mode;

a current peak detecting unit, configured to detect a current current peak of the inductor;

a first working mode determining unit, configured to determine that the power factor correction circuit operates in a current continuous mode when a current current peak of the inductor is greater than a current peak of the inductor when the power factor correction circuit operates in a current critical mode ;

Determining that the power factor correction circuit operates in a current critical mode when a current current peak of the inductor is equal to a current peak of the inductor when the power factor correction circuit operates in a current critical mode;

The power factor correction circuit is determined to operate in a current discontinuous mode when a current current peak of the inductor is less than a current peak of the inductor when the power factor correction circuit operates in a current critical mode.
The AC voltage RMS acquisition device of the PFC power supply of claim 20, wherein the power factor correction circuit further comprises a fast recovery diode, and the second preset calculation formula is:

Ipeak= (Vdc + Vfrd - Vigbt) / L × D (1-D) × Ts;

Where Ipeak is the current peak current of the inductor, and Vdc is the voltage across the electrolytic capacitor, Vfrd For the turn-on voltage drop of the fast recovery diode, Vigbt is the turn-on voltage drop of the power switch tube, L is the inductance value of the inductor, and D is the duty cycle of the power switch tube on-time, Ts The switching period of the power switch tube.
The AC voltage RMS acquisition device of the PFC power supply of claim 20, wherein the transient voltage acquisition module further comprises:

a first instantaneous voltage obtaining unit, configured to acquire, when the power factor correction circuit operates in a current continuous mode or a current critical mode, a current change amount of the inductor in one switching cycle of the power switch tube, and according to The current change amount and the third preset calculation formula acquire an instantaneous value of the input AC voltage of the PFC power source;

a second instantaneous voltage obtaining unit, configured to acquire an opening time of the power switch tube in one switching cycle when the power factor correction circuit operates in a current interrupt mode, and according to the power switch tube in one cycle The opening and the fourth preset calculation formula obtain the instantaneous value of the input AC voltage of the PFC power source.
The apparatus of claim 22, wherein the PFC power source further comprises a rectifier bridge, the power factor correction circuit further comprising a fast recovery diode, and the third preset calculation formula for:

Vac = Vdc × (1-D) + Vigbt × D + Vfrd × (1-D) + Vbd + L × ΔIin / Ts;

Wherein, Vac is the instantaneous value of the input AC voltage of the PFC power supply, Vdc is the voltage across the electrolytic capacitor, D is the duty ratio of the on-time of the power switch, and Vigbt is the conduction voltage drop of the power switch. Vfrd is the conduction voltage drop of the fast recovery diode, Vbd is the conduction voltage drop of the rectifier bridge, L is the inductance value of the inductor, and ΔIin is the inductance of the inductor in a switching cycle of the power switch tube The amount of current change, Ts is the switching period of the power switch tube.
The AC voltage RMS acquisition device of the PFC power supply of claim 22, wherein the PFC power supply further comprises a rectifier bridge, and the fourth preset calculation formula is:

Vac = L × Ipeak / Ton + Vigbt + Vbd;

Where, Vac is the instantaneous value of the input AC voltage of the PFC power supply, L is the inductance value of the inductor, Ipeak is the current peak value of the inductor, and Ton is the opening time of the power switch tube in one switching cycle, and Vigb is the The conduction voltage drop of the power switch tube, Vbd is the conduction voltage drop of the rectifier bridge.
The AC voltage RMS acquisition device of the PFC power supply of claim 17, wherein the instantaneous voltage acquisition module comprises:

a second voltage detecting subunit for detecting a voltage across the electrolytic capacitor;

a second state acquiring subunit, configured to acquire a duty cycle of a switching period and an on time of the power switch tube;

a current midpoint value calculation unit, configured to calculate power according to a voltage across the electrolytic capacitor, a switching period of the power switch tube, a duty ratio of an on-time of the power switch tube, and a fifth preset calculation formula a current midpoint value of the inductor when the factor correction circuit operates in a current critical mode;

a current midpoint value detecting unit, configured to detect a current current midpoint value of the inductor;

a second working mode determining unit, configured to determine that the power factor correction circuit works when a current midpoint value of the inductor is greater than a current midpoint value of the inductor when the power factor correction circuit operates in a current critical mode In current continuous mode;

The current current midpoint value of the inductor is equal to a current midpoint value of the inductor when the power factor correction circuit operates in a current critical mode, and determining that the power factor correction circuit operates in a current critical mode;

The power factor correction circuit is determined to operate in a current discontinuous mode when a current midpoint value of the inductor is less than a current midpoint value of the inductor when the power factor correction circuit operates in a current critical mode.
The AC voltage RMS acquisition device of the PFC power supply of claim 25, wherein the power factor correction circuit further comprises a fast recovery diode, and the fifth preset calculation formula is:

Imid = (Vdc + Vfrd - Vigbt) / L × D (1-D) × Ts/2;

Where Imid is the current current midpoint value of the inductor, and Vdc is the voltage across the electrolytic capacitor, Vfrd For the turn-on voltage drop of the fast recovery diode, Vigbt is the turn-on voltage drop of the power switch tube, L is the inductance value of the inductor, and D is the duty cycle of the power switch tube on-time, Ts The switching period of the power switch tube.
The AC voltage RMS acquisition device of the PFC power supply of claim 25, wherein the instantaneous voltage acquisition module further comprises:

a third instantaneous voltage acquiring unit, configured to acquire a current change amount of the inductor in one switching cycle of the power switch tube when the power factor correction circuit operates in a current continuous mode or a current critical mode, and according to the The current variation amount and the sixth preset calculation formula obtain an instantaneous value of the input AC voltage of the PFC power source;

a fourth instantaneous voltage obtaining unit, configured to acquire an opening time of the power switch tube in one switching cycle when the power factor correction circuit operates in a current interrupt mode, and according to the power switch tube in one cycle The turn-on time and the seventh preset calculation formula obtain the instantaneous value of the input AC voltage of the PFC power source.
The AC voltage RMS obtaining device of the PFC power supply of claim 27, wherein the PFC power supply further comprises a rectifier bridge, the power factor correction circuit further comprises a fast recovery diode, and the sixth preset calculation formula for:

Vac = Vdc × (1-D) + Vigbt × D + Vfrd × (1-D) + Vbd + L × ΔIin / Ts;

Wherein, Vac is the instantaneous value of the input AC voltage of the PFC power supply, Vdc is the voltage across the electrolytic capacitor, D is the duty ratio of the on-time of the power switch, and Vigbt is the conduction voltage drop of the power switch. Vfrd is the conduction voltage drop of the fast recovery diode, Vbd is the conduction voltage drop of the rectifier bridge, L is the inductance value of the inductor, and ΔIin is the inductance of the inductor in a switching cycle of the power switch tube The amount of current change, Ts is the switching period of the power switch tube.
The AC voltage RMS acquisition device of the PFC power supply of claim 27, wherein the PFC power supply further comprises a rectifier bridge, and the seventh preset calculation formula is:

Vac = L × (Imid × 2) / Ton + Vigbt + Vbd;

Where, Vac is the instantaneous value of the input AC voltage of the PFC power supply, L is the inductance value of the inductor, Imid is the current midpoint value of the inductor, and Ton is the opening time of the power switch tube in one switching cycle, Vigbt For the conduction voltage drop of the power switch tube, Vbd is the conduction voltage drop of the rectifier bridge.
The AC voltage RMS acquisition device of the PFC power supply according to claim 17, wherein the calculation module according to the effective value is specifically configured to:

Calculating an AC voltage effective value of the PFC power source according to the input AC voltage peak value and an eighth preset formula; or calculating an AC voltage effective value of the PFC power source according to the input AC voltage instantaneous value and a ninth preset formula;

The eighth preset formula is Vac_rms = Vac_peak / sqrt(2);

The ninth preset formula is: Vac_rms = sqrt( LPF(Vac×Vac) );

Among them, Vac_rms is the AC voltage RMS value of the PFC power supply, Vac_peak is the AC voltage peak value of the power supply, sqrt(2) is the square root operation of the number "2", and Vac is the instantaneous value of the AC voltage of the power supply. LPF (Vac × Vac) is a low-pass filtering operation on (Vac × Vac), and sqrt ( LPF (Vac × Vac)) is a pair ( LPF (Vac × Vac) ) Perform an square root operation.
The AC voltage RMS acquisition device of the PFC power supply of claim 17, wherein the current operating parameters of the PFC power supply comprise:

At least one of a current power value of a load connected to the PFC power source, a current input current value of the PFC power source, and a current input current peak value of the PFC power source.
An AC voltage RMS acquisition device for a PFC power supply according to claim 31, wherein:

The current operating parameters of the PFC power supply satisfy the conditions for the power factor correction circuit of the PFC power supply to be turned off, including:

The current power value of the load connected to the PFC power source is less than the preset power value, or the current input current value of the PFC power source is less than the preset input current value, or the current input current peak value of the PFC power source is less than the preset input current peak value. ;

The current operating parameters of the PFC power supply satisfy the conditions for the power factor correction circuit of the PFC power supply to be turned on include:

The current power value of the load connected to the PFC power source is greater than or equal to the preset power value, or the current input current value of the PFC power source is greater than or equal to the preset input current value, or the current input current peak value of the PFC power source is greater than or equal to The preset input current peak.