WO2016082418A1

WO2016082418A1 - Power factor control method and apparatus

Info

Publication number: WO2016082418A1
Application number: PCT/CN2015/076139
Authority: WO
Inventors: 王斌
Original assignee: 广东科龙空调器有限公司
Priority date: 2014-11-27
Filing date: 2015-04-09
Publication date: 2016-06-02
Also published as: CN105591535B; CN105591535A

Abstract

Disclosed are a power factor control method and apparatus. The method includes: acquiring an input voltage value; calculating a duty cycle of turn-on time of a chopper tube to a carrier period according to the input voltage value and a pre-set output voltage target value; and controlling the turn-on time or turn-off time of the chopper tube (708), or the carrier period according to the duty cycle, wherein the turn-off time of the chopper tube is not less than a first pre-set time, the turn-on time of the chopper tube is not less than a third pre-set time, the first pre-set time plus the third pre-set time is less than a second pre-set time, and the second pre-set time is a rated period of the chopper tube. The method and apparatus can improve electromagnetic compatibility of a power electronic apparatus, and reduces loss of a power switch tube.

Description

Power factor control method and device

Technical field

The present invention relates to the field of power electronics, and in particular, to a power factor control method and apparatus.

Background technique

With the rapid development of power electronics technology, the application of various power electronic devices has become increasingly widespread, and the resulting harmonic pollution has become increasingly serious. In order to reduce the harmonic pollution caused by the power electronic device to the power grid, a Power Factor Correction (PFC) circuit is usually added on the input side of the power electronic device to convert the input current into a sine wave in phase with the input voltage. Improve the output capability of the line and reduce the harmonic current in the circuit, thereby reducing the electromagnetic interference (Electro Magnetic Interference, EMI) of the power electronic device and improving its Electromagnetic Compatibility (EMC).

In the prior art, there are many methods for performing power factor correction on power electronic devices, but most of them are implemented by a fixed carrier frequency (abbreviation: carrier frequency) and a fixed output voltage. In the operation of the PFC circuit, if the MCU controls the power switch tube with a single carrier frequency, the carrier will have a narrow turn-off pulse width in the valley phase of the mains voltage (as shown in A of FIG. 1). A narrower turn-on pulse width occurs at the peak of the mains voltage (as shown in B of Figure 1). On the one hand, these narrow pulse widths make the turn-off time and on-time of the power switch tube extremely short, which reduces the power factor correction effect of the PFC circuit, and causes the EMI of the power electronic device to increase and the EMC to deteriorate. On the other hand, these narrower pulse widths cause the power switch tube to be quickly turned off or turned on, resulting in increased losses in the power switch tube.

In the prior art, there is also a scheme for realizing power factor correction by a variable carrier frequency. The scheme realizes power on and off by controlling a signal generation circuit and a shutdown signal generation circuit, thereby controlling power. The switch tube works in frequency conversion mode, and finally achieves the purpose of power factor correction for the power electronic device. Although this type of scheme realizes variable carrier frequency, if the frequency is peaked and biased to the highest frequency direction at the valley or peak stage of the mains voltage, the carrier will be made to have a narrower turn-off or turn-on pulse width, resulting in power electronics. The device produces greater electromagnetic interference.

Therefore, it is a technical problem to be solved to find a power factor control method capable of improving the EMC of a power electronic device while reducing the loss of the power switch tube.

Summary of the invention

Embodiments of the present invention provide a power factor control method and apparatus, which can at least solve the problem of EMC variation of a power electronic device caused by an existing power factor control method, and an increase in power switch tube loss, and can improve a power electronic device. EMC, while reducing the loss of the power switch tube.

In order to achieve the above object, embodiments of the present invention adopt the following technical solutions:

In a first aspect, a power factor control method is provided, including:

Collecting input voltage values;

Calculating a duty ratio of the on-time of the chopper tube to the carrier period according to the input voltage value and the preset output voltage target value;

Controlling, according to the duty ratio, an on-time, or an off-time, or a carrier period of the chopper, wherein the chopping time of the chopper is not less than a first preset time, the chopping The conduction time of the tube is not less than a third preset time, the first preset time + the third preset time <the second preset time, and the second preset time is the rated value of the chopper tube cycle.

According to the power factor control method provided by the embodiment of the present invention, the off time of the chopper tube is not less than the first preset time and the on time by controlling the on time, or the off time, or the carrier period of the chopper tube. Not less than the third preset time, so that the carrier does not have a narrow turn-off pulse width at the valley of the input voltage, and a narrow turn-on pulse width does not occur at the peak of the input voltage. Therefore, compared with the prior art, the power factor control method provided by the embodiment of the present invention can prevent the carrier from having a narrow turn-off pulse width in the trough phase of the mains, and a narrow turn-on pulse width in the peak phase, thereby enabling Overcoming the problems of the prior art, the EMC variation of the power electronic device caused by the narrow opening or closing pulse width, and the increase of the power switch tube loss can improve the EMC of the power electronic device and reduce the loss of the power switch tube.

In a second aspect, a power factor control apparatus is provided, including: an acquisition unit, a calculation unit, and a first control unit;

The collecting unit is configured to collect an input voltage value;

The calculating unit is configured to calculate, according to the input voltage value and the preset output voltage target value, a duty cycle of the chopper tube to occupy a duty cycle of the carrier cycle;

The first control unit is configured to control the guiding of the chopper tube according to the duty ratio a turn-on time, or a turn-off time, or a carrier cycle, wherein a turn-off time of the chopper tube is not less than a first preset time, and an on-time of the chopper tube is not less than a third preset time, The first preset time + the third preset time <the second preset time, the second preset time is the rated period of the chopper tube.

The power factor control device provided by the embodiment of the present invention controls the turn-on time, off time, or carrier period of the chopper tube so that the turn-off time of the chopper tube is not less than the first preset time and the on-time Not less than the third preset time, so that the change of the carrier period is synchronized with the change of the phase of the power frequency voltage, and the carrier does not have a narrow turn-off pulse width in the valley of the input voltage, and the peak of the input voltage does not occur. A narrower conduction pulse width appears. Therefore, compared with the prior art, the power factor control apparatus provided by the embodiment of the present invention can avoid a narrow turn-off pulse width of a carrier in a trough of a commercial power, and a narrow open pulse width in a peak stage, which can be overcome. In the prior art, the EMC variation of the power electronic device caused by the narrow opening or closing pulse width and the increase of the power switch tube loss can improve the EMC of the power electronic device and reduce the loss of the power switch tube. Variable carrier frequency control.

DRAWINGS

1 is a schematic waveform diagram of a carrier wave in the prior art;

2 is a schematic flowchart 1 of a power factor control method according to an embodiment of the present invention;

3 is a schematic flowchart 2 of a power factor control method according to an embodiment of the present invention;

4 is a schematic circuit diagram 1 of a power factor correction according to an embodiment of the present invention;

FIG. 5 is a schematic circuit diagram 2 of a power factor correction according to an embodiment of the present disclosure;

6 is a schematic structural diagram 1 of a power factor control apparatus according to an embodiment of the present invention;

FIG. 7 is a schematic structural diagram 2 of a power factor control apparatus according to an embodiment of the present disclosure;

FIG. 8 is a schematic structural diagram 3 of a power factor control apparatus according to an embodiment of the present disclosure;

FIG. 9 is a schematic structural diagram 4 of a power factor control apparatus according to an embodiment of the present invention.

detailed description

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, but not all 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.

In order to facilitate the clear description of the technical solutions of the embodiments of the present invention, in the embodiments of the present invention, the words "first", "second" and the like are used to distinguish the same or similar items whose functions and functions are substantially the same, in the field. The skilled person will understand that the words "first", "second" and the like do not limit the number and order of execution.

It should be noted that the present invention is applicable to a plurality of PFC circuits. Hereinafter, only an interleaved PFC circuit and a normal PFC circuit will be described as an example.

Embodiment 1

An embodiment of the present invention provides a power factor control method, as shown in FIG. 2, including:

S201. The power factor control device collects an input voltage value.

S202. The power factor control device calculates a duty ratio of the on-time of the chopper tube to the carrier period according to the input voltage value and the preset output voltage target value.

S203. The power factor control device controls the on-time, the off-time, or the carrier period of the chopper according to the duty ratio.

The turn-off time of the chopper tube is not less than the first preset time, and the on-time of the chopper tube is not less than the third preset time, the first preset time + the third preset time <the second preset time, The second preset time is the rated period of the chopper tube.

Specifically, as shown in FIG. 3, an embodiment of the present invention provides a power factor control method, where a power factor control device controls an on-time, or an off-time, or a carrier cycle of a chopper according to the duty ratio. (Step S203), specifically, the method may include:

S203a, when the input voltage is increased by a small value after the zero crossing point, the power factor control device controls the off time of the chopper tube to be the first preset time, and determines the carrier period of the chopper according to the duty ratio and the off time. Wherein, the carrier period of the chopper tube is gradually reduced.

S203b, after the carrier period of the chopper tube reaches the second preset time, the power factor control device controls the carrier period of the chopper tube to be maintained at the second preset time, and determines the guidance of the chopper tube according to the duty ratio and the carrier period. The transit time, in which the on-time of the chopper tube is gradually reduced.

S203c, after the on-time of the chopper tube reaches the third preset time, the power factor control device controls the on-time of the chopper tube to remain at the third preset time, and determines the chopping wave according to the duty ratio and the on-time The carrier cycle of the tube, wherein the carrier period of the chopper tube gradually increases.

S203d, when the input voltage is greatly reduced after the peak point, the power factor control device controls the on-time of the chopper to be maintained at the third preset time, and determines the carrier period of the chopper according to the duty ratio and the on-time. Wherein, the carrier period of the chopper tube is gradually reduced.

S203e, after the carrier period of the chopper tube reaches the second preset time, the power factor control device controls the carrier period of the chopper tube to be maintained at the second preset time, and determines the chopping tube according to the duty ratio and the carrier period. Break time, in which the turn-off time of the chopper tube gradually decreases.

S203f, after the off time of the chopper tube reaches the first preset time, the power factor control device controls the off time of the chopper tube to be maintained at the first preset time, and determines the chopping according to the duty ratio and the off time. The carrier cycle of the tube, wherein the carrier period of the chopper tube gradually increases until the input voltage reaches a zero crossing.

Specifically, in the power factor control method provided by the embodiment of the present invention, the power factor control device calculates the duty ratio of the chopping tube to the carrier cycle according to the input voltage value and the preset output voltage target value (step S202). ), can include:

The power factor control device calculates the on-time as the duty cycle of the carrier cycle according to the input voltage value and the preset output voltage target value in combination with the first preset formula. The first preset formula is shown in formula (1):

D=1-Vin/Vout formula (1)

Where D represents the duty cycle, Vin represents the input voltage value, and Vout represents the preset output voltage target value.

Specifically, in the power factor control method provided by the embodiment of the present invention, in the steps S203a and S203f, the power factor control device determines the carrier period of the chopper according to the duty ratio and the off time, and may include:

The power factor control device calculates the carrier period of the chopper according to the duty ratio and the off time in combination with the second preset formula. The second preset formula is shown in formula (2):

To=tb/(1-D) Formula (2)

Where To represents the carrier period, tb represents the off time, and D represents the duty cycle.

Specifically, in the power factor control method provided by the embodiment of the present invention, in step S203b, the power factor control device determines the on-time of the chopper according to the duty ratio and the carrier cycle. Specifically, it may include:

The power factor control device calculates the on-time of the chopper according to the duty ratio and the carrier period in combination with the third preset formula. The third preset formula is shown in formula (3):

Ta=To*D formula (3)

Where ta represents the on-time, To represents the carrier period, and D represents the duty cycle.

Specifically, in the power factor control method provided by the embodiment of the present invention, in the steps S203c and S203d, the power factor control device determines the carrier period of the chopper according to the duty ratio and the on-time, which may include:

The power factor control device calculates the carrier period of the chopper tube according to the duty ratio and the on-time, in combination with the fourth preset formula. The fourth preset formula is shown in formula (4):

To=ta/D formula (4)

Where To represents the carrier period, ta represents the on-time, and D represents the duty cycle.

Specifically, in the power factor control method provided by the embodiment of the present invention, in step S203e, the power factor control device determines the turn-off time of the chopper according to the duty ratio and the carrier cycle, and may include:

The power factor control device calculates the turn-off time of the chopper according to the duty ratio and the carrier period in combination with the fifth preset formula. The fifth preset formula is shown in formula (5):

Tb=To*(1-D) formula (5)

Where tb represents the off time, To represents the carrier period, and D represents the duty cycle.

It should be noted that, in the foregoing implementation process of the embodiment of the present invention, the calculation of the duty ratio of the on-time of the carrier cycle, the carrier period of the chopper, and the turn-off time and the on-time of the chopper are It is only a specific calculation method provided by the embodiment of the present invention. It will be readily understood by those skilled in the art that there are other calculation methods in the prior art, which will not be further described in the embodiments of the present invention.

Preferably, the power factor control method provided by the embodiment of the present invention may further include:

The MCU compensates the output voltage according to the sixth preset formula.

The sixth preset formula includes formula (6) and formula (7):

V' _out =V _out +A×V(θ) Equation (6)

V(θ)=V(180°-θ) Equation (7)

Where V _out represents the output voltage target value, V' _out represents the compensated output voltage value, A represents the compensation amplitude, θ represents the input voltage phase, and V(θ), V(180°-θ) both represent the input voltage phase θ The function.

It should be noted that, in the foregoing compensation method provided by the embodiment of the present invention, the function V(θ) satisfies: within a half-frequency cycle between two consecutive zero-crossing points of the commercial power, In the range of 0°<θ<90°, V(θ) decreases as θ increases; at θ=90°, V(θ) is the smallest; in the range of 90°<θ<180°, V(θ) increases as θ increases. Illustratively, V(θ) may be a cos θ, a 1-sin θ function, etc., which are not specifically limited in the embodiment of the present invention. In this way, in the valley phase of the mains voltage, the output voltage can be increased, thereby improving the power supply to the subsequent stage, while reducing the output voltage reduction, reducing the ripple of the output voltage, and improving the output voltage. Sex.

It should be noted that the output voltage target value V _out can be adjusted according to the control needs. That is, when the voltage required by the load is low, the value of V _out can be appropriately lowered; conversely, when the voltage required by the load is high, the value of V _out can be appropriately increased. Thus, the output voltage can achieve best match the needs of the load by V _out, reduce the dynamic switching losses of the PFC circuit.

Exemplarily, assuming that the output voltage target value V _out = 330V and the compensation amplitude A=100 according to the load demand, according to the detected phase of the input voltage is θ, the formula for compensating the output voltage is as shown in formula (8). Show:

V' _out = 330 + 100 × cos θ formula (8)

Further, in the above method for compensating the output voltage target value, the compensation amplitude A can be compensated according to the input current, thereby further compensating for the output voltage. Exemplarily, assuming that the formula for compensating the output voltage target value is the formula (8), after adding the compensation for the compensation amplitude A, the compensation formula is as shown in the formula (9):

Formula (9)

Wherein, V' _out represents the compensated output voltage value; I _in represents the input current value; B is a constant, and the value of B can be adjusted according to the control needs, for example, when I _in ≤ 5A, B=0.9 When I _in >5A, let B = 1.

The MCU performs voltage regulation control on the output voltage according to the seventh preset formula.

The seventh preset formula includes formula (8) and formula (9):

D'=D+ΔD formula (8)

_{_{ΔD = k p * (ΔV n}} -ΔV n-1) + k i * ΔV n Formula (9)

Where D represents the duty ratio, ΔD represents the compensation increase amount of the duty ratio D, D′ represents the compensated duty ratio, and ΔV _n represents the difference between the output voltage target value and the output voltage value in the nth carrier cycle. ΔV _n-1 represents the difference between the output voltage target value and the output voltage value in the n-1th carrier period, and k _p and k _i are constant.

It should be noted that the compensation of the duty cycle can indirectly compensate the output voltage, so that the output voltage is maintained in a relatively stable range, thereby ensuring the stability of the power supply.

Illustratively, in combination with the foregoing implementation steps of the embodiments of the present invention, two specific circuit schematics using the power factor control method provided by the embodiment of the present invention are given, as shown in FIG. 4 and FIG. 5 respectively. The PFC circuit 707 used in FIG. 4 is an interleaved PFC circuit, and the PFC circuit 807 used in FIG. 5 is a common PFC circuit; the rectifying unit 701 and the rectifying unit 801 are used for rectifying the input current, and the voltage/phase detecting unit 703 and The voltage/phase detecting unit 803 is configured to detect the voltage value and phase of the input voltage, the current detecting unit 702 and the current detecting unit 802 are configured to detect the input current value, the driving unit 704 is configured to drive the power switch tube 708, and the driving unit 804 is configured to drive The power switch 808, the voltage detecting unit 706 and the voltage detecting unit 806 are used to detect the output voltage value, the MCU 705 is used to control the PFC circuit 707, and the MCU 805 is used to control the PFC circuit 807.

Illustratively, taking the first half-frequency cycle of the input voltage as an example, the stages of power factor correction using the preferred power factor control method provided by the embodiments of the present invention are described in detail:

The first stage: when the phase of the input voltage is 0° and the input voltage is in the valley phase, that is, when the input voltage is 0, the off time of the MCU control chopper is the first preset time.

At this stage, the turn-off time of the chopper is a fixed value, so the carrier does not have a narrow turn-off pulse width. As the phase of the input voltage increases, the amplitude of the input voltage increases from small. According to formula (1), the on-time of the carrier cycle is gradually reduced; according to formula (2), the carrier cycle is known. Will gradually decrease. When the carrier period is less than or equal to the second preset time, the second phase is entered. Among them, since the turn-off time of the chopper tube is a fixed value, the on-time of the chopper tube is also gradually reduced.

The second stage: the carrier period of the MCU control chopper is the second preset time.

At this stage, the carrier period is a fixed value, and as the phase of the input voltage increases, the duty ratio of the on-time to the carrier period continues to decrease. According to formula (5), 斩 The turn-off time of the wave tube will increase, and the on-time of the chopper will continue to decrease due to the constant carrier period. When the phase of the input voltage reaches around 90°, the on-time is less than the third preset time and enters the third stage.

The third stage: the MCU controls the on-time of the chopper to be the third preset time.

At this stage, the on-time of the chopper tube is a fixed value, so the carrier does not have a narrow turn-on pulse width.

When the phase of the input voltage exceeds 90°, but is still around 90°, it enters the fourth stage.

The fourth stage: the MCU controls the on-time of the chopper to be the third preset time.

At this stage, the on-time of the chopper tube is still a fixed value. As the phase of the input voltage increases, according to formula (1), the on-time of the carrier cycle will gradually increase; according to formula (4), the carrier cycle will gradually decrease, when the carrier cycle After being less than or equal to the second preset time, it enters the fifth stage. Among them, since the on-time of the chopper tube is a fixed value, the turn-off time of the chopper tube is also gradually reduced.

The fifth stage: the carrier period of the MCU control chopper tube is the second preset time.

At this stage, the carrier period is a fixed value, and as the phase of the input voltage increases, the on-time of the carrier cycle continues to increase. According to formula (5), the turn-off time of the chopper tube will continue to decrease. When the phase of the input voltage reaches around 180°, the off time may be less than the first preset time and enter the sixth stage.

The sixth stage: the off time of the MCU control chopper is the first preset time.

At this stage, the turn-off time of the chopper is a fixed value, so the carrier does not have a narrow turn-off pulse width.

At this point, the power factor correction of the first half-frequency cycle has been completed, and the power factor correction of the next half-frequency cycle can be completed by repeating the above stages.

In summary, it is apparent that the power factor control method provided by the embodiments of the present invention can avoid a narrow pulse width of a carrier during a valley and a peak of an input voltage.

In the power factor control method provided by the embodiment of the present invention, the power factor control device collects the input voltage value, and calculates the duty time of the chopper tube to occupy the duty cycle of the carrier cycle according to the input voltage value and the preset output voltage target value. Ratio, then, according to the duty ratio, controlling the on-time, or the off-time, or the carrier period of the chopper, wherein the off-time of the chopper is not less than the first preset time, and the chopper is turned on The time is not less than the third preset time, And the first preset time + the third preset time <the second preset time, the second preset time is the rated period of the chopper tube. According to the power factor control method provided by the embodiment of the present invention, the off time of the chopper tube is not less than the first preset time and the on time by controlling the on time, or the off time, or the carrier period of the chopper tube. Not less than the third preset time, so that the carrier does not have a narrow turn-off pulse width at the valley of the input voltage, and a narrow turn-on pulse width does not occur at the peak of the input voltage. Therefore, compared with the prior art, the power factor control method provided by the embodiment of the present invention can prevent the carrier from having a narrow turn-off pulse width in the trough phase of the mains, and a narrow turn-on pulse width in the peak phase, which can be overcome. In the prior art, the EMC variation of the power electronic device caused by the narrow opening or closing pulse width and the increase of the power switch tube loss can improve the EMC of the power electronic device and reduce the loss of the power switch tube. Variable carrier frequency control.

Embodiment 2

The embodiment of the present invention provides a power factor control device 60, as shown in FIG. 6, which includes an acquisition unit 601, a calculation unit 602, and a first control unit 603.

The collecting unit 601 is configured to collect an input voltage value.

The calculating unit 602 is configured to calculate a duty ratio of the on-time of the chopper tube to the carrier period according to the input voltage value and the preset output voltage target value;

The first control unit 603 is configured to control an on-time, or an off-time, or a carrier period of the chopper according to the duty ratio, wherein the chopping time of the chopper is not less than the first preset time, and the chopping The conduction time of the tube is not less than the third preset time, the first preset time + the third preset time <the second preset time, and the second preset time is the rated period of the chopper tube.

Further, as shown in FIG. 7, the first control unit 603 may specifically include: a control module 603a, and a determining module 603b.

The control module 603a is configured to control the off time of the chopper tube to be the first preset time when the input voltage is increased from small after the zero crossing point.

The determining module 603b is configured to determine a carrier period of the chopper according to the duty ratio and the off time, wherein the carrier period of the chopper is gradually decreased.

The control module 603a is further configured to: after the carrier period of the chopper tube reaches the second preset time, the carrier period of the control chopper tube is maintained at the second preset time.

The determining module 603b is further configured to determine an on-time of the chopper according to the duty ratio and the carrier period, wherein the on-time of the chopper is gradually decreased.

The control module 603a is further configured to: when the on-time of the chopper tube reaches the third preset time, the on-time of the control chopper tube is maintained at the third preset time.

The determining module 603b is further configured to determine a carrier period of the chopper according to the duty ratio and the on-time, wherein the carrier period of the chopper is gradually increased.

The control module 603a is further configured to maintain the on-time of the chopper tube at a third preset time when the input voltage is greatly reduced after the peak point.

The determining module 603b is further configured to determine a carrier period of the chopper according to the duty ratio and the on-time, wherein the carrier period of the chopper is gradually decreased.

The determining module 603b is further configured to determine an off time of the chopper according to the duty ratio and the carrier period, wherein the off time of the chopper is gradually decreased.

The control module 603a is further configured to: after the off time of the chopper tube reaches the first preset time, control the off time of the chopper tube to be maintained at the first preset time.

The determining module 603b is further configured to determine a carrier period of the chopper according to the duty ratio and the off time, wherein the carrier period of the chopper is gradually increased until the input voltage reaches a zero crossing.

Specifically, in the power factor control device 60 provided by the embodiment of the present invention, the calculating unit 602 is specifically configured to:

According to the input voltage value and the preset output voltage target value, combined with the first preset formula, the on-time is calculated as the duty cycle of the carrier cycle, and the first preset formula includes:

D=1-Vin/Vout,

Preferably, in the power factor control device 60 provided by the embodiment of the present invention, the determining module 603b is specifically configured to:

According to the duty ratio and the off time, combined with the second preset formula, the carrier period of the chopper tube is calculated, wherein the second preset formula includes:

To=tb/(1-D),

Preferably, in the power factor control device 60 provided by the embodiment of the present invention, the determining module 603b is further specifically configured to:

According to the duty cycle and carrier cycle, combined with the third preset formula, calculate the conduction of the chopper Time, wherein the third preset formula includes:

Ta=To*D,

According to the duty ratio and the on-time, combined with the fourth preset formula, the carrier period of the chopper tube is calculated, wherein the fourth preset formula includes:

To=ta/D,

According to the duty ratio and the carrier cycle, combined with the fifth preset formula, the turn-off time of the chopper is calculated, wherein the fifth preset formula includes:

Tb=To*(1-D),

Further, as shown in FIG. 8 , the power factor control device 60 provided by the embodiment of the present invention may further include: a compensation unit 604.

The compensation unit 604 is configured to compensate the output voltage according to the sixth preset formula. The sixth preset formula includes:

V' _out = V _out + A × V (θ), V (θ) = V (180 ° - θ),

Where V _out represents the output voltage target value, V' _out represents the compensated output voltage target value, A represents the compensation amplitude, θ represents the input voltage phase, and V(θ), V(180°-θ) both represent the input voltage phase. The function of θ.

Further, as shown in FIG. 9, the power factor control device 60 provided by the embodiment of the present invention may further include: a second control unit 605.

The second control unit 605 is configured to perform voltage stabilization control on the output voltage according to the seventh preset formula, where the seventh preset formula includes:

D'=D+ΔD, ΔD=k _p *(ΔV _n -ΔV _n-1 )+k _i *ΔV _n ,

Specifically, the method for performing power factor control by the power factor control device 60 provided by the embodiment of the present invention can be referred to the description of the first embodiment, and details are not described herein again.

According to the power factor control device provided by the embodiment of the present invention, the input voltage value is collected by the acquisition unit, and the calculation unit calculates the conduction time of the chopper tube as the carrier cycle according to the input voltage value and the preset output voltage target value. The air ratio, then, the control unit controls the on-time, or the off-time, or the carrier period of the chopper according to the duty ratio, wherein the chopping time of the chopper is not less than the first preset time, chopping The conduction time of the tube is not less than the third preset time, and the first preset time + the third preset time < the second preset time, and the second preset time is the rated period of the chopper tube. The power factor control device provided by the embodiment of the present invention controls the turn-on time, off time, or carrier period of the chopper tube so that the turn-off time of the chopper tube is not less than the first preset time and the on-time Not less than the third preset time, so that the change of the carrier period is synchronized with the change of the phase of the power frequency voltage, and the carrier does not have a narrow turn-off pulse width in the valley of the input voltage, and the peak of the input voltage does not occur. A narrower conduction pulse width appears. Therefore, compared with the prior art, the power factor control apparatus provided by the embodiment of the present invention can avoid a narrow turn-off pulse width of a carrier in a trough of a commercial power, and a narrow open pulse width in a peak stage, which can be overcome. In the prior art, the EMC variation of the power electronic device caused by the narrow opening or closing pulse width and the increase of the power switch tube loss can improve the EMC of the power electronic device and reduce the loss of the power switch tube.

It will be clearly understood by those skilled in the art that, for convenience and brevity of description, the above described device is only illustrated by the division of the above functional modules. In practical applications, the above functions may be assigned differently according to needs. The function module is completed, that is, the internal structure of the device is divided into different functional modules to complete all or part of the functions described above. For the specific working process of the system, the device and the unit described above, refer to the corresponding process in the foregoing method embodiment, and details are not described herein again.

In the several embodiments provided by the present application, it should be understood that the disclosed system, apparatus, and method may be implemented in other manners. For example, the device embodiments described above are merely illustrative. For example, the division of modules or units is only a logical function division. In actual implementation, there may be another division manner, for example, multiple units or components may be combined or Can be integrated into another system, or some features can be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection through some interface, device or unit, and may be in an electrical, mechanical or other form.

The units described as separate components may or may not be physically separate, and the components displayed as units may or may not be physical units, that is, may be located in one place, or may be distributed to multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of the embodiment.

In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above integrated unit can be implemented in the form of hardware or in the form of a software functional unit.

An integrated unit, if implemented in the form of a software functional unit and sold or used as a standalone product, can be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present invention, which is essential or contributes to the prior art, or all or part of the technical solution, may be embodied in the form of a software product stored in a storage medium. A number of instructions are included to cause a computer device (which may be a personal computer, server, or network device, etc.) or a processor to perform all or part of the steps of the various embodiments of the present invention. The foregoing storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk, and the like. .

The above is only the specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily think of changes or substitutions within the technical scope of the present invention. It is within the scope of the invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

A power factor control method, the method comprising:

Collecting input voltage values;

Calculating a duty ratio of the on-time of the chopper tube to the carrier period according to the input voltage value and the preset output voltage target value;

Controlling, according to the duty ratio, an on-time, or an off-time, or a carrier period of the chopper, wherein the chopping time of the chopper is not less than a first preset time, the chopping The conduction time of the tube is not less than a third preset time, the first preset time + the third preset time <the second preset time, and the second preset time is the rated value of the chopper tube cycle.
The method according to claim 1, wherein the controlling the on-time, or the off-time, or the carrier period of the chopper according to the duty ratio comprises:

Controlling an off time of the chopper tube to be the first predetermined time when the input voltage is increased by a small value after a zero crossing point, and determining the according to the duty ratio and the off time a carrier period of the chopper tube, wherein a carrier period of the chopper tube is gradually decreased;

After the carrier period of the chopper tube reaches the second preset time, controlling a carrier period of the chopper tube is maintained at the second preset time, and according to the duty ratio and the carrier period Determining an on-time of the chopper tube, wherein an on-time of the chopper tube is gradually decreased;

After the on-time of the chopper tube reaches the third predetermined time, controlling an on-time of the chopper tube is maintained at the third preset time, and according to the duty ratio and the The on-time determines a carrier period of the chopper tube, wherein a carrier period of the chopper tube gradually increases;

When the input voltage is greatly reduced after the peak point, controlling the on-time of the chopper tube is maintained at the third preset time, and determining the according to the duty ratio and the on-time a carrier period of the chopper tube, wherein a carrier period of the chopper tube is gradually decreased;

After the carrier period of the chopper tube reaches the second preset time, controlling a carrier period of the chopper tube is maintained at the second preset time, and according to the duty ratio and the carrier period Determining an off time of the chopper tube, wherein a turn-off time of the chopper tube is gradually decreased;

After the off time of the chopper tube reaches the first preset time, controlling an off time of the chopper tube is maintained at the first preset time, and according to the duty ratio and the The turn-off time determines a carrier period of the chopper tube, wherein a carrier period of the chopper tube gradually increases until the input voltage reaches a zero crossing.
The method according to claim 1, wherein the calculating the on-time of the chopper as a duty cycle of the carrier period according to the input voltage value and the preset output voltage target value comprises:

And calculating a duty ratio of the on-time of the chopper tube to the carrier period according to the input voltage value and the preset output voltage target value, in combination with the first preset formula, where the first preset formula includes:

D=1-Vin/Vout,

Where D represents the duty cycle, Vin represents the input voltage value, and Vout represents the preset output voltage target value.
The method according to claim 2 or 3, wherein the determining the carrier period of the chopper according to the duty ratio and the off time comprises:

Calculating a carrier period of the chopper tube according to the duty ratio and the off time, in combination with a second preset formula, where the second preset formula includes:

To=tb/(1-D),

Where To represents the carrier period, tb represents the off time, and D represents the duty cycle.
The method according to claim 2 or 3, wherein the determining the on-time of the chopper according to the duty ratio and the carrier period comprises:

And calculating, according to the duty ratio and the carrier cycle, the on-time of the chopper tube according to a third preset formula, where the third preset formula includes:

Ta=To*D,

Where ta represents the on-time, To represents the carrier period, and D represents the duty cycle.
The method according to claim 2 or 3, wherein the determining the carrier period of the chopper according to the duty ratio and the on-time comprises:

Calculating a carrier period of the chopper tube according to the duty ratio and the on-time, in combination with a fourth preset formula, where the fourth preset formula includes:

To=ta/D,

Where To represents the carrier period, ta represents the on-time, and D represents the duty cycle.
The method according to claim 2 or 3, wherein the determining the off time of the chopper according to the duty ratio and the carrier period comprises:

Calculating, according to the duty ratio and the carrier period, a turn-off time of the chopper tube according to a fifth preset formula, where the fifth preset formula includes:

Tb=To*(1-D),

Where tb represents the off time, T represents the carrier period, and D represents the duty cycle.
The method according to any one of claims 1 to 7, wherein the method further comprises:

The output voltage target value is compensated according to a sixth preset formula, where the sixth preset formula includes:

V' out = V out + A × V (θ), V (θ) = V (180 ° - θ),

Where V out represents the output voltage target value, V' out represents the compensated output voltage target value, A represents the compensation amplitude, θ represents the input voltage phase, and V(θ), V(180°-θ) both represent the input voltage phase. The function of θ.
The method of any of claims 1-8, wherein the method further comprises:

According to the seventh preset formula, the output voltage is regulated, and the seventh preset formula includes:

D'=D+ΔD, ΔD=k p *(ΔV n -ΔV n-1 )+k i *ΔV n ,

Where D represents the duty ratio, ΔD represents the compensation increase amount of the duty ratio D, D′ represents the compensated duty ratio, and ΔV n represents the difference between the output voltage target value and the output voltage value in the nth carrier cycle. ΔV n-1 represents the difference between the output voltage target value and the output voltage value in the n-1th carrier period, and k p and k i are constant.
A power factor control device, comprising: an acquisition unit, a calculation unit, and a first control unit;

The collecting unit is configured to collect an input voltage value;

The calculating unit is configured to calculate, according to the input voltage value and the preset output voltage target value, a duty cycle of the chopper tube to occupy a duty cycle of the carrier cycle;

The first control unit is configured to control an on-time, or an off-time, or a carrier period of the chopper according to the duty ratio, wherein a turn-off time of the chopper is not less than a preset time, the on-time of the chopper tube is not less than a third preset time, the first preset time + the third preset time <the second preset time, the second preset The time is the rated period of the chopper tube.
The apparatus according to claim 10, wherein the first control unit comprises: a control module, and a determining module;

The control module is configured to control an off time of the chopper tube to be the first preset time when the input voltage is increased by a small value after a zero crossing point;

The determining module is configured to determine a carrier period of the chopper according to the duty ratio and the off time, wherein a carrier period of the chopper is gradually decreased;

The control module is further configured to: after the carrier period of the chopper tube reaches the second preset time, control a carrier period of the chopper tube to be maintained at the second preset time;

The determining module is further configured to determine an on-time of the chopper according to the duty ratio and the carrier period, wherein an on-time of the chopper is gradually decreased;

The control module is further configured to: after the on-time of the chopper tube reaches the third preset time, control an on-time of the chopper tube to be maintained at the third preset time;

The determining module is further configured to determine a carrier period of the chopper according to the duty ratio and the on-time, wherein a carrier period of the chopper is gradually increased;

The control module is further configured to: when the input voltage is greatly reduced after a peak point, control an on-time of the chopper tube to be maintained at the third preset time;

The determining module is further configured to determine a carrier period of the chopper according to the duty ratio and the on-time, wherein a carrier period of the chopper is gradually decreased;

The determining module is further configured to determine an off time of the chopper according to the duty ratio and the carrier period, wherein a turn-off time of the chopper is gradually decreased;

The control module is further configured to: after the off time of the chopper tube reaches the first preset time, control an off time of the chopper tube to be maintained at the first preset time;

The determining module is further configured to determine a carrier period of the chopper according to the duty ratio and the off time, wherein a carrier period of the chopper is gradually increased until the input voltage reaches Zero crossing.
The device according to claim 10, wherein the calculating unit is specifically configured to:

And calculating a duty ratio of the on-time of the chopper tube to the carrier period according to the input voltage value and the preset output voltage target value, in combination with the first preset formula, where the first preset formula includes:

D=1-Vin/Vout,

Where D represents the duty cycle, Vin represents the input voltage value, and Vout represents the preset output voltage target value.
The device according to claim 11 or 12, wherein the determining module is specifically configured to:

Calculating the 斩 according to the duty ratio and the turn-off time in combination with a second preset formula The carrier cycle of the wave tube, wherein the second preset formula includes:

To=tb/(1-D),

Where To represents the carrier period, tb represents the off time, and D represents the duty cycle.
The device according to claim 11 or 12, wherein the determining module is further configured to:

And calculating, according to the duty ratio and the carrier cycle, the on-time of the chopper tube according to a third preset formula, where the third preset formula includes:

Ta=To*D,

Where ta represents the on-time, To represents the carrier period, and D represents the duty cycle.
The device according to claim 11 or 12, wherein the determining module is further configured to:

Calculating a carrier period of the chopper tube according to the duty ratio and the on-time, in combination with a fourth preset formula, where the fourth preset formula includes:

To=ta/D,

Where To represents the carrier period, ta represents the on-time, and D represents the duty cycle.
The device according to claim 11 or 12, wherein the determining module is further configured to:

Calculating, according to the duty ratio and the carrier period, a turn-off time of the chopper tube according to a fifth preset formula, where the fifth preset formula includes:

Tb=To*(1-D),

Where tb represents the off time, To represents the carrier period, and D represents the duty cycle.
The device according to any one of claims 10-16, wherein the device further comprises: a compensation unit;

The compensation unit is configured to compensate an output voltage target value according to a sixth preset formula, where the sixth preset formula includes:

V' out = V out + A × V (θ), V (θ) = V (180 ° - θ),

Where V out represents the output voltage target value, V' out represents the compensated output voltage target value, A represents the compensation amplitude, θ represents the input voltage phase, and V(θ), V(180°-θ) both represent the input voltage phase. The function of θ.
The device according to any one of claims 10-17, wherein the device further comprises: a second control unit;

The second control unit is configured to regulate the output voltage according to the seventh preset formula Control, the seventh preset formula includes:

D'=D+ΔD, ΔD=k p *(ΔV n -ΔV n-1 )+k i *ΔV n ,

Where D represents the duty ratio, ΔD represents the compensation increase amount of the duty ratio D, D′ represents the compensated duty ratio, and ΔV n represents the difference between the output voltage target value and the output voltage value in the nth carrier cycle. ΔV n-1 represents the difference between the output voltage target value and the output voltage value in the n-1th carrier period, and k p and k i are constant.