CN113346733A - Bridgeless PFC circuit control method and device, electronic equipment and storage medium - Google Patents

Bridgeless PFC circuit control method and device, electronic equipment and storage medium Download PDF

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Publication number
CN113346733A
CN113346733A CN202110559441.5A CN202110559441A CN113346733A CN 113346733 A CN113346733 A CN 113346733A CN 202110559441 A CN202110559441 A CN 202110559441A CN 113346733 A CN113346733 A CN 113346733A
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input voltage
switching device
voltage
pfc circuit
input
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赵秀峰
闫正国
李锋
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Beijing Dynamic Power Co Ltd
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Beijing Dynamic Power Co Ltd
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/42—Circuits or arrangements for compensating for or adjusting power factor in converters or inverters
    • H02M1/4208—Arrangements for improving power factor of AC input
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/08—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/44—Circuits or arrangements for compensating for electromagnetic interference in converters or inverters
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
    • Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Rectifiers (AREA)

Abstract

One or more embodiments of the invention disclose a bridgeless PFC circuit control method, a bridgeless PFC circuit control device, a storage medium and an electronic device, wherein the bridgeless PFC circuit control method comprises the following steps: acquiring a first input voltage of a first voltage input end and a second input voltage of a second voltage input end of a PFC circuit; and controlling the duty ratio of an energy storage switching device and a follow current switching device in the PFC circuit according to the first input voltage and the second input voltage so as to reduce the rising rate of the potential of the second voltage input end before the zero crossing of the alternating current input voltage, wherein when the energy storage switching device is in a conducting state, the energy storage switching device of an inductor in the PFC circuit is enabled to store energy, and when the follow current switching device is in the conducting state, the inductor is enabled to release energy to a load of the PFC circuit. The embodiment of the invention can slow down the larger step voltage change rate caused by the zero crossing of the input voltage, thereby inhibiting the peak current generated by the PFC circuit when the input voltage crosses zero.

Description

Bridgeless PFC circuit control method and device, electronic equipment and storage medium
Technical Field
The invention relates to the technical field of switching power supplies, in particular to a bridgeless PFC circuit control method and device, electronic equipment and a storage medium.
Background
A PFC (Power Factor Correction) converter is an important device for reducing harmonic pollution and reactive pollution to a Power grid of a switching Power supply, and is widely applied to an input stage of the switching Power supply. The conduction loss of a diode bridge rectifier circuit in the traditional PFC converter limits the improvement of the whole efficiency of the converter, and a bridgeless PFC circuit appears in order to eliminate the loss increased by a diode bridge. However, the common mode conducted noise performance of the bridgeless PFC circuit is not ideal, which prevents the converter from being widely used. Therefore, noise reduction of conducted EMI (Electromagnetic Interference) is of great significance to spread the application of the bridgeless technology.
Fig. 1 shows a schematic diagram of an overhead bridgeless PFC converter circuit, as shown in fig. 1, when the ac input voltage changes from positive to negative or from negative to positive, the common terminal potential of diodes D1 and D2 changes abruptly, which is the main cause of common mode conducted noise of the converter. The capacitor is respectively connected with the D1 and the D2 in parallel, so that the change of the step voltage can be slowed down, the spike current generated when the input voltage is zero-crossed is restrained, and CM (Common Mode) noise caused by pulse current can be reduced.
Because resonance exists between the parallel capacitor and the energy storage inductor L, the resonance current flowing through L becomes larger when the polarity of the input current changes every time. Large resonant currents can reduce converter conversion efficiency, especially at low loads. In addition, the resonant current also causes DM (Differential Mode) noise.
Alternatively, the above problem can be solved by adding an auxiliary circuit to the totem-pole bridgeless PFC converter, and after the ac input voltage crosses zero, the auxiliary circuit can alternately turn on the auxiliary switching device, so that the resonant current is consumed by the auxiliary resistor or is slowly absorbed by the auxiliary inductor. However, adding complex auxiliary circuits increases the cost of the converter and occupies more space in the converter, which affects the power density of the converter.
Disclosure of Invention
In view of the above, one or more embodiments of the present invention provide a bridgeless PFC circuit control method, device, electronic device and storage medium, which can slow down a large step voltage change rate caused by a zero crossing of an input voltage, so as to suppress a spike current generated when the input voltage of the PFC circuit crosses zero.
According to one or more embodiments of the invention, a bridgeless PFC circuit control method is provided, which includes: acquiring a first input voltage of a first voltage input end and a second input voltage of a second voltage input end of the PFC circuit; controlling duty ratios of an energy storage switching device and a follow current switching device in the PFC circuit according to the first input voltage and the second input voltage to reduce a rising rate of a potential of the second voltage input end before zero crossing of the alternating current input voltage, wherein when the energy storage switching device is in a conducting state, an inductor in the PFC circuit is enabled to store energy, and when the follow current switching device is in the conducting state, the inductor is enabled to release energy to a load of the PFC circuit.
Optionally, the PFC circuit includes: the first voltage input end, the second voltage input end, the inductance the first switching device the second switching device, third switching device and fourth switching device, electric capacity and resistance, first voltage input end passes through the inductance respectively with the first pole of first switching device and the second pole of second switching device links to each other, the second pole of first switching device respectively with the one end of third switching device, the one end of electric capacity and the one end of resistance links to each other, the first pole of second switching device respectively with the one end of fourth switching device, the other end of electric capacity and the other end of resistance links to each other, second voltage input end respectively with the other end of fourth switching device and the other end of third switching device links to each other.
Optionally, controlling duty ratios of an energy storage switching device and a freewheeling switching device in the PFC circuit according to the first input voltage and the second input voltage to reduce a rising rate of a potential of the second voltage input terminal before a zero crossing of the ac input voltage, includes: acquiring the first input voltage and the second input voltage at preset time intervals; comparing the first input voltage with the second input voltage to obtain a comparison result; calculating a difference between the first input voltage and the second input voltage; judging whether the difference value is smaller than a preset value or not, and judging whether the alternating current input voltage is continuously reduced or not according to the difference value to obtain a judgment result; and controlling duty ratios of an energy storage switching device and a follow current switching device in the PFC circuit according to the judgment result and the comparison result so as to reduce the rising rate of the potential of the second voltage input end before the zero crossing of the alternating current input voltage.
Optionally, controlling duty ratios of an energy storage switching device and a freewheeling switching device in the PFC circuit according to the first input voltage and the second input voltage to reduce a rising rate of a potential of the second voltage input terminal before a zero crossing of the ac input voltage, includes: and controlling the first switching device to be switched on and the second switching device to be switched off in response to the comparison result that the first input voltage is greater than the second input voltage and the judgment result that the alternating current input voltage is continuously reduced and is smaller than the preset value.
Optionally, controlling the first switching device to be turned on and the second switching device to be turned off includes: and controlling the first switching device to be switched on according to a pre-established corresponding relation between the on-time and the off-time of the first switching device when the first input voltage is greater than the second input voltage, and/or controlling the second switching device to be switched off according to a pre-established corresponding relation between the on-time and the off-time of the second switching device when the first input voltage is greater than the second input voltage.
Optionally, controlling duty ratios of an energy storage switching device and a freewheeling switching device in the PFC circuit according to the first input voltage and the second input voltage to reduce a rising rate of a potential of the second voltage input terminal before a zero crossing of the ac input voltage, includes: and controlling the first switching device to be switched off and the second switching device to be switched on in response to the comparison result that the first input voltage is smaller than the second input voltage and the judgment result that the alternating current input voltage is continuously reduced and smaller than the preset value.
Optionally, controlling the first switching device to be turned off and the second switching device to be turned on includes: and controlling the second switching device to be switched on according to a pre-established corresponding relation between the on-time and the off-time of the second switching device when the first input voltage is smaller than the second input voltage, and/or controlling the first switching device to be switched off according to a pre-established corresponding relation between the on-time and the off-time of the first switching device when the first input voltage is smaller than the second input voltage.
One or more embodiments of the present invention also provide a bridgeless PFC circuit control apparatus, including: the device comprises an acquisition module, a detection module and a control module, wherein the acquisition module is configured to acquire a first input voltage of a first voltage input end and a second input voltage of a second voltage input end of a bridgeless Power Factor Correction (PFC) circuit before an alternating current input voltage of the PFC circuit crosses zero; the control module is configured to control duty ratios of an energy storage switching device and a freewheeling switching device in the PFC circuit according to the first input voltage and the second input voltage so as to reduce a rising rate of a potential of the second voltage input end before a zero crossing of the alternating-current input voltage, wherein the energy storage switching device is a switching device which enables an inductor in the PFC circuit to store energy when in a conducting state, and the freewheeling switching device is a switching device which enables the inductor to release energy to a load of the PFC circuit when in the conducting state.
One or more embodiments of the present invention also provide an electronic device including: a processor; and a memory having stored thereon computer-executable instructions that, when executed by the processor, are operable to implement any of the above-described bridgeless PFC circuit control methods.
One or more embodiments of the present invention also provide a computer-readable storage medium having stored thereon computer-executable instructions, which when executed by a processor, are used to implement any one of the above-mentioned bridgeless PFC circuit control methods.
In the bridgeless PFC circuit control method, apparatus, storage medium, and electronic device provided in one or more embodiments of the present invention, by obtaining a first input voltage and a second input voltage of a PFC circuit, and controlling duty ratios of an energy storage switching device and a freewheeling switching device in the PFC circuit according to the first input voltage and the second voltage input, since a difference between the first input voltage and the second input voltage is an ac input voltage of the PFC, a timing of a zero crossing of the ac input voltage may be determined according to the obtained first input voltage and the obtained second input voltage, so as to reduce a rising rate of a potential of an input terminal of the second voltage before the zero crossing of the ac input voltage by controlling the duty ratios of the energy storage switching device and the freewheeling switching device in the PFC circuit before the zero crossing of the ac input voltage, thereby suppressing a spike current generated when the voltage of the PFC circuit crosses zero, common mode noise can be effectively inhibited, an auxiliary circuit does not need to be added in a bridgeless PFC circuit, and manufacturing cost and power density of the converter are not influenced.
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 description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
Fig. 1 is a schematic diagram illustrating a PFC circuit according to one or more embodiments of the present invention;
fig. 2 is a flow diagram illustrating a bridgeless PFC circuit control method according to one or more embodiments of the present disclosure;
fig. 3 is a schematic structural diagram illustrating a bridgeless PFC circuit control apparatus according to one or more embodiments of the present invention;
fig. 4 is a schematic structural diagram of an electronic device according to one or more embodiments of the present invention.
Detailed Description
Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.
It should be understood that the described embodiments are only some embodiments of the invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The PFC circuit shown in fig. 1 operates in a BCM (critical Conduction Mode) Mode, and has a Conduction time T within one cycle of the grid input voltageONIt can be considered fixed, the input current follows the input voltage, and the power factor approaches 1. Inductor voltage V at rising stage of inductor currentONAnd its action time TONThe product of (a) is necessarily equal to the inductor voltage V during the inductor current reduction phaseOFFAnd its action time TOFFThe product of (a):
VON×TON＝VOFF×TOFF；
the inductor voltage is the instantaneous input voltage V in the rising stage of the inductor currentIN(ii) a In the stage of inductor current reduction, the inductor voltage is the difference (V) between the instantaneous output voltage and the input voltageOUT-VIN)：
VIN×TON＝(VOUT-VIN)×TOFF；
In the vicinity of the zero crossing of the input voltage, the inductive energy storage time TONLong, follow current time TOFFIn short, the duty ratios of the switching devices S1 and S2 vary greatly before and after the zero crossing of the input voltage, so as to form a step voltage, and further generate a peak current in a parasitic capacitor of the circuit.
Fig. 2 is a flow chart illustrating a bridgeless PFC circuit control method according to one or more embodiments of the present invention, as shown in fig. 2, the method including:
step 201: before the alternating-current input voltage of a bridgeless PFC circuit crosses zero, acquiring a first input voltage of a first voltage input end and a second input voltage of a second voltage input end of the PFC circuit;
the PFC circuit is also exemplified by fig. 1, wherein the first voltage input terminal may be, for example, the L terminal shown in fig. 1, and the second voltage input terminal may be, for example, the N terminal shown in fig. 1. In the PFC circuit shown in fig. 1, a set of resistors R1 and R2, through which the first input voltage is detected, is connected between the terminal L and ground; similarly, a set of resistors R3 and R4 is connected between the terminal N and ground, through which the second input voltage is detected.
Step 202: controlling duty ratios of an energy storage switching device and a follow current switching device in the PFC circuit according to the first input voltage and the second input voltage to reduce a rising rate of a potential of the second voltage input end before zero crossing of the alternating current input voltage, wherein when the energy storage switching device is in a conducting state, an inductor in the PFC circuit is enabled to store energy, and when the follow current switching device is in the conducting state, the inductor is enabled to release energy to a load of the PFC circuit.
Wherein the energy storage switching device and the freewheeling switching device in the circuit are switchable when the PFC circuit is in different working stages. For example, in one ac voltage cycle of the PFC circuit, the first switching device may function as an energy storage switching device and may function as a freewheeling switching device as the ac input voltage changes, and similarly, the second switching device may function as the freewheeling switching device. Still taking the PFC circuit shown in fig. 1 as an example, in a positive half cycle (VL > VN) of the ac input voltage, during the periods of turning on at S2 (which is an example of the second switching device) and turning off at S1 (which is an example of the first switching device), the current flows from the input voltage L terminal through Lr, S2 and D2, and returns to the input voltage N terminal, the inductor current rises in a positive direction, and the inductor stores energy, where S2 is an energy storage switching device; when the switch is turned off at S2 and turned on at S1, current flows from the L end of the input voltage to the N end of the input voltage through Lr, S1, Co | | | RL and D2, the inductor current drops in the positive direction, the inductor releases energy to the output load, and S1 is a follow current switching device. In the negative half cycle (VN > VL) of the alternating current input voltage, during the periods that S1 is conducted and S2 is turned off, current flows from the input voltage N end to the input voltage L end through D1, S1 and Lr, the inductive current rises reversely, and the inductor stores energy, wherein S1 is an energy storage switching device; during the turn-off of S1 and the turn-on of S2, current flows from the input voltage N terminal through D1, Co | | | RL, S2, Lr, and returns to the input voltage L terminal, the inductor current decreases in the reverse direction, the inductor releases energy to the output load, and at this time, S2 is a freewheeling switching device.
The AC input voltage of the PFC circuit can be obtained by subtracting the first input voltage and the second input voltage, therefore, in step 202, after the first input voltage and the second input voltage are obtained, the situation of the alternating current input voltage can be known, the first input voltage and the second input voltage are continuously obtained, the time when the alternating current input voltage is about to cross zero can be determined, and simultaneously, according to the first input voltage and the second input voltage, it can be determined whether the PFC circuit is currently operating in the upper half cycle (the upper half cycle when the first input voltage is greater than the second input voltage) or the lower half cycle (the lower half cycle when the first input voltage is less than the second input voltage) of an ac voltage cycle, and further, the duty ratios of the first switching device and the second switching device can be controlled according to the alternating voltage period of the PFC circuit.
The bridgeless PFC circuit control method according to one or more embodiments of the present invention obtains a first input voltage and a second input voltage of a PFC circuit, controls a duty ratio of an energy storage switching device and a freewheeling switching device in the PFC circuit according to the first input voltage and the second voltage, and determines a zero crossing time of an ac input voltage according to the obtained first input voltage and the obtained second input voltage because a difference between the first input voltage and the second input voltage is an ac input voltage of the PFC circuit, so as to reduce a rising rate of a potential of a second voltage input terminal before the ac input voltage crosses zero by controlling the duty ratios of the energy storage switching device and the freewheeling switching device in the PFC circuit before the ac input voltage crosses zero, thereby suppressing a peak current generated when the voltage of the PFC circuit crosses zero, and effectively suppressing a common mode noise, and an auxiliary circuit is not required to be added in the bridgeless PFC circuit, so that the manufacturing cost and the power density of the converter are not influenced.
In one or more embodiments of the present invention, taking the PFC circuit shown in fig. 1 as an example, the PFC circuit may include: the first voltage input terminal L, the second voltage input terminal N, the inductor Lr, the first switching device S1, the second switching device S2, the third switching device D1 and the fourth switching device D2, a capacitor Co and a resistor RL, the first voltage input terminal L is respectively connected to a first pole of the first switching device S1 and a second pole of the second switching device S2 through the inductor Lr, a second pole of the first switching device S1 is connected to one end of the third switching device D1, one end of the capacitor Co, and one end of the resistor RL, a first pole of the second switching device S2 is connected to one terminal of the fourth switching device D2, the other terminal of the capacitor Co, and the other terminal of the resistor RL, the second voltage input terminal N is connected to the other end of the fourth switching device D2 and the other end of the third switching device D1, respectively. Fig. 1 is only an exemplary PFC circuit shown in one or more embodiments of the present invention, and the PFC circuit of one or more embodiments of the present invention may also be a PFC circuit with another structure, for example, the PFC circuit may be composed of electronic components that are partially different from those in the PFC circuit shown in fig. 1 (for example, diodes D1 and D2 shown in fig. 1 may be replaced by other switching devices with smaller conduction losses), or may be another PFC circuit with a circuit structure that is not completely consistent with the PFC circuit structure.
In one example, the PFC circuit may further include: a first sampling resistor, a second sampling resistor, a third sampling resistor, a fourth sampling resistor and a microprocessor, wherein the first sampling resistor (R1 shown in FIG. 1) and the second sampling resistor (R2 shown in FIG. 1) are connected in series between the first input terminal and ground, the third sampling resistor (e.g., R3 shown in fig. 1) and the fourth sampling resistor (e.g., R4 shown in fig. 1) are connected in series between the second voltage input terminal and ground, the microprocessor acquires the first input voltage by collecting the voltage across the second sampling resistor, acquires the second input voltage by collecting the voltage across the fourth sampling resistor, so that the duty ratio of the energy storage switching device and the follow current switching device in the PFC circuit can be controlled according to the collected first input voltage and the second input voltage, to reduce the rate of rise of the potential at the second voltage input before the ac input voltage crosses zero.
In one or more embodiments of the present invention, controlling duty cycles of an energy storage switching device and a freewheeling switching device in the PFC circuit according to the first input voltage and the second input voltage to reduce a rising rate of a potential of the second voltage input terminal before a zero crossing of the ac input voltage may include:
acquiring the first input voltage and the second input voltage at preset time intervals; following the above example, the microprocessor may periodically collect the first input voltage and the second input voltage at preset time intervals.
Comparing the first input voltage with the second input voltage to obtain a comparison result; the comparison result may include, for example: the first input voltage is greater than the second input voltage, which is greater than the first input voltage. For example, if the first input voltage is greater than the second input voltage, it indicates that the current half cycle of the ac input voltage is being performed, and if the second input voltage is greater than the first input voltage, it indicates that the current half cycle of the ac input voltage is being performed.
Calculating a difference between the first input voltage and the second input voltage; for example, the difference between the first input voltage and the second input voltage may be calculated each time the first input voltage and the second input voltage are acquired.
Judging whether the difference value is smaller than a preset value or not, and judging whether the alternating current input voltage is continuously reduced or not according to the difference value to obtain a judgment result;
for example, after the first input voltage and the second input voltage are periodically obtained once, the difference between the first input voltage and the second input voltage is calculated, and whether the difference is smaller than the preset value is determined.
For example, whether the ac input voltage continuously decreases may be determined by comparing a difference between the first input voltage and the second input voltage calculated at least two times before and after, and assuming that the difference between the first input voltage and the second input voltage calculated at the previous time is 3V and the difference between the first input voltage and the second input voltage calculated at the subsequent time is 1V, for example, it may be determined that the ac input voltage continuously decreases.
And controlling duty ratios of an energy storage switching device and a follow current switching device in the PFC circuit according to the judgment result and the comparison result so as to reduce the rising rate of the potential of the second voltage input end before the zero crossing of the alternating current input voltage.
It should be noted that, the order of executing the steps of determining the determination result and the comparison result is not limited, for example, the determination result may be determined first, and then the comparison result is determined, or the comparison result may be determined first, and then the determination result is determined, which is not limited in the embodiment of the present invention.
In one or more embodiments of the present invention, controlling duty cycles of an energy storage switching device and a freewheeling switching device in the PFC circuit according to the first input voltage and the second input voltage to reduce a rising rate of a potential of the second voltage input terminal before a zero crossing of the ac input voltage may include:
and controlling the first switching device to be switched on and the second switching device to be switched off in response to the comparison result that the first input voltage is greater than the second input voltage and the judgment result that the alternating current input voltage is continuously reduced and is smaller than the preset value.
Still taking the PFC circuit shown in fig. 1 as an example, in the positive half cycle (VL > VN) of the ac input voltage, when it is detected that the ac input voltage gradually decreases and is smaller than the first preset value, S2 is turned off, S1 is turned on, so that the inductor current ir continues to flow in the reverse direction after the forward direction decreases to zero, the parasitic capacitance at the two ends of D2 is charged, and the potential at the N-terminal increases. The rising rate of the N-end potential can be limited by controlling the on-time and the off-time of the S1, the change of the N-end step voltage when the alternating current input voltage is from positive to negative to zero crossing is slowed down, the peak current generated by the alternating current input voltage is further inhibited, and the common mode noise can be effectively reduced. In the vicinity of the zero crossing of the alternating-current input voltage, the input current does not change along with the input voltage, but the current in the period is very small, and the influence on THD A (input current total harmonic distortion) and Power Factor (PF) indexes is very small.
In one or more embodiments of the present invention, the on-time and the off-time of the first switching device vary with the variation of the potential of the N terminal, and a two-dimensional data table consisting of the on-time and the off-time of S1 in the positive half-cycle of the ac input voltage may be obtained in advance by means of a plurality of experimental tests and stored in the memory space of the microprocessor. When the AC input voltage is detected to be gradually reduced and smaller than the first preset value, the on-time and the off-time of S1 are controlled according to the two-dimensional data table, and the on-time and the off-time of S2 are controlled to further reduce the on-loss. In view of this, in one or more embodiments of the present invention, in a case where the first input voltage is smaller than the second input voltage, the ac input voltage continuously decreases and is smaller than the preset value, the controlling the first switching device to be turned on and the second switching device to be turned off may include: and controlling the first switching device to be switched on according to a pre-established corresponding relation between the on-time and the off-time of the first switching device when the first input voltage is greater than the second input voltage, and/or controlling the second switching device to be switched off according to a pre-established corresponding relation between the on-time and the off-time of the second switching device when the first input voltage is greater than the second input voltage.
In one or more embodiments of the present invention, controlling duty cycles of an energy storage switching device and a freewheeling switching device in the PFC circuit according to the first input voltage and the second input voltage to reduce a rising rate of a potential of the second voltage input terminal before a zero crossing of the ac input voltage may include:
and controlling the first switching device to be switched off and the second switching device to be switched on in response to the comparison result that the first input voltage is smaller than the second input voltage and the judgment result that the alternating current input voltage is continuously reduced and smaller than the preset value. Still taking the PFC circuit shown in fig. 1 as an example, in a negative half period (VN > VL) of the ac input voltage, when it is detected that the ac input voltage gradually decreases and is smaller than the preset value, S1 is turned off, S2 is turned on, so that the inductor current ir continues to flow in a positive direction after decreasing to zero in a negative direction, and discharges parasitic capacitors at two ends of D2, and the potential at the N end decreases. The on-time and the off-time of the S2 are controlled to limit the drop rate of the N-end potential, slow down the change of the N-end step voltage when the alternating current input voltage goes from negative to positive to zero, further restrain the peak current generated by the alternating current input voltage, and effectively reduce the common mode noise. Near the zero crossing of the alternating current input voltage, the input current does not change with the input voltage, but the current in the period is very small, and the influence on the Total Harmonic Distortion (THDA) and the Power Factor (PF) index of the input current is very small.
In one or more embodiments of the present invention, the on-time and the off-time of S2 are changed with the change of the potential of the N terminal, and a two-dimensional data table consisting of the on-time and the off-time of S2 in the negative half-cycle of the ac input voltage may be obtained in advance through a plurality of experimental tests and stored in the memory space of the microprocessor. When the AC input voltage is detected to be gradually reduced and less than the preset value, the on time and the off time of S2 are controlled according to the data table. Controlling both the on-time and the off-time of S1 may further reduce the on-loss. Based on this, in one or more embodiments of the present invention, controlling the first switching device to be turned off and the second switching device to be turned on may include: and controlling the second switching device to be switched on according to a pre-established corresponding relation between the on-time and the off-time of the second switching device when the first input voltage is smaller than the second input voltage, and/or controlling the first switching device to be switched off according to a pre-established corresponding relation between the on-time and the off-time of the first switching device when the first input voltage is smaller than the second input voltage.
It should be noted that, in the PFC circuit according to one or more embodiments of the present invention, when the consistency of the switching devices is better, the pre-established correspondence between the on-time and the off-time of the first switching device when the first input voltage is greater than the second input voltage may be consistent with the pre-established correspondence between the on-time and the off-time of the first switching device when the first input voltage is less than the second input voltage.
Fig. 3 is a schematic diagram illustrating a structure of a bridgeless PFC circuit control apparatus according to one or more embodiments of the present invention, and as shown in fig. 3, the apparatus 30 includes:
an obtaining module 31 configured to obtain a first input voltage at a first voltage input terminal and a second input voltage at a second voltage input terminal of a bridgeless Power Factor Correction (PFC) circuit before an AC input voltage of the PFC circuit crosses zero; a control module 32 configured to control duty cycles of an energy storage switching device and a freewheeling switching device in the PFC circuit according to the first input voltage and the second input voltage to reduce a rising rate of a potential of the second voltage input terminal before a zero crossing of the ac input voltage, where the energy storage switching device is a switching device that enables an inductor in the PFC circuit to store energy when in a conducting state, and the freewheeling switching device is a switching device that enables the inductor to release energy to a load of the PFC circuit when in the conducting state.
In one or more embodiments of the present invention, the control module may be specifically configured to:
acquiring the first input voltage and the second input voltage at preset time intervals;
comparing the first input voltage with the second input voltage to obtain a comparison result;
calculating a difference between the first input voltage and the second input voltage;
judging whether the difference value is smaller than a preset value or not, and judging whether the alternating current input voltage is continuously reduced or not according to the difference value to obtain a judgment result;
and controlling duty ratios of an energy storage switching device and a follow current switching device in the PFC circuit according to the judgment result and the comparison result so as to reduce the rising rate of the potential of the second voltage input end before the zero crossing of the alternating current input voltage.
In one or more embodiments of the present invention, the control module may be specifically configured to:
and controlling the first switching device to be switched on and the second switching device to be switched off in response to the comparison result that the first input voltage is greater than the second input voltage and the judgment result that the alternating current input voltage is continuously reduced and is smaller than the preset value.
In one or more embodiments of the present invention, the control module may be specifically configured to:
and controlling the first switching device to be switched on according to a pre-established corresponding relation between the on-time and the off-time of the first switching device when the first input voltage is greater than the second input voltage, and/or controlling the second switching device to be switched off according to a pre-established corresponding relation between the on-time and the off-time of the second switching device when the first input voltage is greater than the second input voltage.
In one or more embodiments of the present invention, the control module may be specifically configured to:
and controlling the first switching device to be switched off and the second switching device to be switched on in response to the comparison result that the first input voltage is smaller than the second input voltage and the judgment result that the alternating current input voltage is continuously reduced and smaller than the preset value.
In one or more embodiments of the present invention, the control module may be specifically configured to:
and controlling the second switching device to be switched on according to a pre-established corresponding relation between the on-time and the off-time of the second switching device when the first input voltage is smaller than the second input voltage, and/or controlling the first switching device to be switched off according to a pre-established corresponding relation between the on-time and the off-time of the first switching device when the first input voltage is smaller than the second input voltage.
One or more embodiments of the present invention also provide an electronic device, including: a processor; and a memory having stored thereon computer-executable instructions that, when executed by the processor, are operable to implement any of the above-described bridgeless PFC circuit control methods.
One or more embodiments of the present invention also provide a computer-readable storage medium having stored thereon computer-executable instructions, which when executed by a processor, are used to implement any one of the above-mentioned bridgeless PFC circuit control methods.
Fig. 4 shows a schematic structural diagram of an electronic device according to one or more embodiments of the present invention, where the electronic device may include: a processor 1010, a memory 1020, an input/output interface 1030, a communication interface 1040, and a bus 1050. Wherein the processor 1010, memory 1020, input/output interface 1030, and communication interface 1040 are communicatively coupled to each other within the device via bus 1050.
The processor 1010 may be implemented by a general-purpose CPU (Central Processing Unit), a microprocessor, an Application Specific Integrated Circuit (ASIC), or one or more Integrated circuits, and is configured to execute related programs to implement the technical solutions provided in the embodiments of the present disclosure.
The Memory 1020 may be implemented in the form of a ROM (Read Only Memory), a RAM (Random Access Memory), a static storage device, a dynamic storage device, or the like. The memory 1020 may store an operating system and other application programs, and when the technical solution provided by the embodiments of the present specification is implemented by software or firmware, the relevant program codes are stored in the memory 1020 and called to be executed by the processor 1010.
The input/output interface 1030 is used for connecting an input/output module to input and output information. The i/o module may be configured as a component in a device (not shown) or may be external to the device to provide a corresponding function. The input devices may include a keyboard, a mouse, a touch screen, a microphone, various sensors, etc., and the output devices may include a display, a speaker, a vibrator, an indicator light, etc.
The communication interface 1040 is used for connecting a communication module (not shown in the drawings) to implement communication interaction between the present apparatus and other apparatuses. The communication module can realize communication in a wired mode (such as USB, network cable and the like) and also can realize communication in a wireless mode (such as mobile network, WIFI, Bluetooth and the like).
Bus 1050 includes a path that transfers information between various components of the device, such as processor 1010, memory 1020, input/output interface 1030, and communication interface 1040.
It should be noted that although the above-mentioned device only shows the processor 1010, the memory 1020, the input/output interface 1030, the communication interface 1040 and the bus 1050, in a specific implementation, the device may also include other components necessary for normal operation.
In addition, those skilled in the art will appreciate that the above-described apparatus may also include only those components necessary to implement the embodiments of the present description, and not necessarily all of the components shown in the figures. It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
All the embodiments in the present specification are described in a related manner, and the same and similar parts among the embodiments may be referred to each other, and each embodiment focuses on the differences from the other embodiments.
In particular, as for the apparatus embodiment, since it is substantially similar to the method embodiment, the description is relatively simple, and for the relevant points, reference may be made to the partial description of the method embodiment.
For convenience of description, the above devices are described separately in terms of functional division into various units/modules. Of course, the functionality of the units/modules may be implemented in one or more software and/or hardware implementations of the invention.
The above description is only for the specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims (10)

1. A bridgeless PFC circuit control method is characterized by comprising the following steps:
acquiring a first input voltage of a first voltage input end and a second input voltage of a second voltage input end of a Power Factor Correction (PFC) circuit;
controlling duty ratios of an energy storage switching device and a follow current switching device in the PFC circuit according to the first input voltage and the second input voltage to reduce a rising rate of a potential of the second voltage input end before zero crossing of the alternating current input voltage, wherein when the energy storage switching device is in a conducting state, an inductor in the PFC circuit is enabled to store energy, and when the follow current switching device is in the conducting state, the inductor is enabled to release energy to a load of the PFC circuit.
2. The method of claim 1, wherein the PFC circuit comprises: the first voltage input end, the second voltage input end, the inductance the first switching device the second switching device, third switching device and fourth switching device, electric capacity and resistance, first voltage input end passes through the inductance respectively with the first pole of first switching device and the second pole of second switching device links to each other, the second pole of first switching device respectively with the one end of third switching device, the one end of electric capacity and the one end of resistance links to each other, the first pole of second switching device respectively with the one end of fourth switching device, the other end of electric capacity and the other end of resistance links to each other, second voltage input end respectively with the other end of fourth switching device and the other end of third switching device links to each other.
3. The method of claim 2, wherein controlling duty cycles of a tank switching device and a freewheeling switching device in the PFC circuit based on the first input voltage and the second input voltage to reduce a rate of rise of a potential of the second voltage input before a zero crossing of the ac input voltage comprises:
acquiring the first input voltage and the second input voltage at preset time intervals;
comparing the first input voltage with the second input voltage to obtain a comparison result;
calculating a difference between the first input voltage and the second input voltage;
judging whether the difference value is smaller than a preset value or not, and judging whether the alternating current input voltage is continuously reduced or not according to the difference value to obtain a judgment result;
and controlling duty ratios of an energy storage switching device and a follow current switching device in the PFC circuit according to the judgment result and the comparison result so as to reduce the rising rate of the potential of the second voltage input end before the zero crossing of the alternating current input voltage.
4. The method of claim 3, wherein controlling duty cycles of a tank switching device and a freewheeling switching device in the PFC circuit based on the first input voltage and the second input voltage to reduce a rate of rise of a potential of the second voltage input before a zero crossing of the AC input voltage comprises:
and controlling the first switching device to be switched on and the second switching device to be switched off in response to the comparison result that the first input voltage is greater than the second input voltage and the judgment result that the alternating current input voltage is continuously reduced and is smaller than the preset value.
5. The method of claim 4, wherein controlling the first switching device to turn on and the second switching device to turn off comprises:
and controlling the first switching device to be switched on according to a pre-established corresponding relation between the on-time and the off-time of the first switching device when the first input voltage is greater than the second input voltage, and/or controlling the second switching device to be switched off according to a pre-established corresponding relation between the on-time and the off-time of the second switching device when the first input voltage is greater than the second input voltage.
6. The method of claim 3, wherein controlling duty cycles of a tank switching device and a freewheeling switching device in the PFC circuit based on the first input voltage and the second input voltage to reduce a rate of rise of a potential of the second voltage input before a zero crossing of the AC input voltage comprises:
and in response to the comparison result that the first input voltage is smaller than the second input voltage and the judgment result that the alternating current input voltage is continuously reduced and smaller than the preset value, controlling the first switching device to be switched off and the second switching device to be switched on.
7. The method of claim 6, wherein controlling the first switching device to be off and the second switching device to be on comprises:
and controlling the second switching device to be switched on according to a pre-established corresponding relation between the on-time and the off-time of the second switching device when the first input voltage is smaller than the second input voltage, and/or controlling the first switching device to be switched off according to a pre-established corresponding relation between the on-time and the off-time of the first switching device when the first input voltage is smaller than the second input voltage.
8. A bridgeless PFC circuit control device is characterized by comprising:
the device comprises an acquisition module, a detection module and a control module, wherein the acquisition module is configured to acquire a first input voltage of a first voltage input end and a second input voltage of a second voltage input end of a bridgeless Power Factor Correction (PFC) circuit before an alternating current input voltage of the PFC circuit crosses zero;
the control module is configured to control duty ratios of an energy storage switching device and a freewheeling switching device in the PFC circuit according to the first input voltage and the second input voltage so as to reduce a rising rate of a potential of the second voltage input end before a zero crossing of the alternating-current input voltage, wherein the energy storage switching device is a switching device which enables an inductor in the PFC circuit to store energy when in a conducting state, and the freewheeling switching device is a switching device which enables the inductor to release energy to a load of the PFC circuit when in the conducting state.
9. An electronic device, comprising:
a processor; and
a memory having stored thereon computer-executable instructions for implementing the bridgeless PFC circuit control method of any one of claims 1-7 when executed by the processor.
10. A computer-readable storage medium having stored thereon computer-executable instructions for implementing the bridgeless PFC circuit control method of any one of claims 1 to 7 when executed by a processor.
CN202110559441.5A 2021-05-21 2021-05-21 Bridgeless PFC circuit control method and device, electronic equipment and storage medium Pending CN113346733A (en)

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