CN108696116A - Totem pfc circuit, pulse width control method, air conditioner and storage medium - Google Patents

Totem pfc circuit, pulse width control method, air conditioner and storage medium Download PDF

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Publication number
CN108696116A
CN108696116A CN201810560783.7A CN201810560783A CN108696116A CN 108696116 A CN108696116 A CN 108696116A CN 201810560783 A CN201810560783 A CN 201810560783A CN 108696116 A CN108696116 A CN 108696116A
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China
Prior art keywords
switch unit
pulsewidth
current
input
unit
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Granted
Application number
CN201810560783.7A
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Chinese (zh)
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CN108696116B (en
Inventor
曾贤杰
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Midea Group Co Ltd
GD Midea Air Conditioning Equipment Co Ltd
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Midea Group Co Ltd
Guangdong Midea Refrigeration Equipment Co Ltd
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Priority to CN201810560783.7A priority Critical patent/CN108696116B/en
Publication of CN108696116A publication Critical patent/CN108696116A/en
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Classifications

    • 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
    • H02M1/4233—Arrangements for improving power factor of AC input using a bridge converter comprising active switches
    • 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
    • H02M1/0048—Circuits or arrangements for reducing losses
    • H02M1/0054—Transistor switching losses
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
    • H03K17/51—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used
    • H03K17/56—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used by the use, as active elements, of semiconductor devices
    • H03K17/687—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used by the use, as active elements, of semiconductor devices the devices being field-effect transistors
    • H03K17/6871—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used by the use, as active elements, of semiconductor devices the devices being field-effect transistors the output circuit comprising more than one controlled field-effect transistor
    • 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)
  • Rectifiers (AREA)

Abstract

The invention discloses a kind of totem pfc circuits, including:Bridge circuit, reactor, bus capacitor and control module, the control module is used for when the input current of the bridge circuit input terminal is less than or equal to predetermined current threshold, according to the input voltage and input current of the bridge circuit input terminal, the pulsewidth when on off state of each switch unit and each switching means conductive is controlled.The invention also discloses a kind of pulse width control method, air conditioner and storage mediums.The present invention realizes while reducing each switch unit on-off times, it is that each switch unit selects suitable pulsewidth according to input voltage and input current, it can be under the premise of meeting the current harmonics requirement of totem pfc circuit, improving the power factor of totem pfc circuit, reduce on-off times, to reduce the number of short circuit current flow, and then reduce switching loss while idle work power in reducing circuit, improve the efficiency of totem pfc circuit.

Description

Totem pfc circuit, pulse width control method, air conditioner and storage medium
Technical field
The present invention relates to air-conditioning technical field more particularly to a kind of totem pfc circuit, pulse width control method, air conditioners And storage medium.
Background technology
With the development of power electronic technique, active PFC (Power Factor Correction, PFC) The advantages that technology is high, harmonic current is small, output voltage stabilization with power factor is widely used.
Currently, the PFC of BOOST types is generally used, this PFC simple structure, convenient controls, but efficiency is more low Under.Therefore, at some to the higher occasion of efficiency requirements, using no bridge totem pfc circuit, this circuit reduce on circuit Number of devices, improve efficiency.
It is single in the scheduled switch of the control once for every half ON/OFF of supply voltage in existing totem pfc circuit The number of member controls the number of totem pfc circuit short circuit currents, improves power factor by the short circuit current.But when When loading bigger, short circuit current flow number is less to make the improvement of power factor insufficient, lead to totem pfc circuit The power of middle idle work is larger;And if the number of short circuit current flow is more, cause switching losses to become larger;Cause totem Column pfc circuit it is less efficient.
The above is only used to facilitate the understanding of the technical scheme, and is not represented and is recognized that the above is existing skill Art.
Invention content
The main purpose of the present invention is to provide a kind of totem pfc circuit, pulse width control method, air conditioner and storages to be situated between Matter, it is intended to solve the less efficient technical problem of existing totem pfc circuit.
To achieve the above object, the present invention provides a kind of totem pfc circuit, and the totem pfc circuit includes:
Bridge circuit, the bridge circuit are equipped with the multiple switch unit for being connected as bridge shape, the bridge circuit Input terminal is connected with AC power, and output end is connected with load;
Reactor, the reactor are arranged between the bridge circuit and the AC power;
Bus capacitor is electrically connected after the bus capacitor is in parallel with the load with the output end of the bridge circuit;
Control module, the control module are used to be more than predetermined current threshold in the input current of the bridge circuit input terminal When value, each switch unit shutdown in the bridge circuit is controlled;And it is less than in the input current of the bridge circuit input terminal Or when equal to predetermined current threshold, according to the input voltage and input current of the bridge circuit input terminal, control each switch The pulsewidth when on off state of unit and each switching means conductive.
In one embodiment, the bridge circuit include first switch unit, second switch unit, third switch unit and 4th switch unit;
The first switch unit is connected in series to form the first branch with the second switch unit, and the third switch is single First to be connected in series to form the second branch with the 4th switch unit, the first branch is connected in parallel to form institute with the second branch State bridge circuit;
The tie point of the first switch unit and the second switch unit is via the reactor and the alternating current Source is electrically connected;The third switch unit is electrically connected with the tie point of the 4th switch unit with the AC power;
The first switch unit is electrically connected with the tie point of the third switch unit with the anode of the bus capacitor; The second switch unit is electrically connected with the tie point of the 4th switch unit with the cathode of the bus capacitor.
In one embodiment, the control module includes:
Current detecting unit, the current detecting unit is electrically connected with the input terminal of the bridge circuit, for detecting State the input current of the input terminal of bridge circuit;
Alternating voltage detection unit, the alternating voltage detection unit are electrically connected with the input terminal of the bridge circuit, are used In the input voltage of the input terminal of detection bridge circuit;
Described control unit is electrically connected with the current detecting unit and the alternating voltage detection unit respectively, is used for When the input current that the current detecting unit detects is less than or equal to predetermined current threshold, according to the current detecting unit The input voltage that the input current and the alternating voltage detection unit detected detects controls each in the bridge circuit The pulsewidth when on off state of a switch unit and each switching means conductive.
In one embodiment, the control module further includes:Drive protection location and driving unit;
Protection location, the driving protection location is driven to be electrically connected respectively with current detecting unit and the driving unit, When input current for being detected in the current detecting unit is more than predetermined current threshold, shutdown control signal is sent to institute State driving unit;
The driving unit is used to control each switch in the bridge circuit according to the shutdown control signal received single Member shutdown;
The input current that described control unit is additionally operable to detect in the current detecting unit is less than or equal to default electricity When flowing threshold value, what the input current and the alternating voltage detection unit that are detected according to the current detecting unit detected Input voltage generates state control signal, and the state control signal is sent to the driving unit;
The driving unit is additionally operable to control each switch in the bridge circuit according to the state control signal received The pulsewidth when on off state of unit and each switching means conductive.
In addition, to achieve the above object, the present invention also provides a kind of pulse width control methods, are applied to above-mentioned totem Pfc circuit, the pulse width control method include the following steps:
When the input current of the bridge circuit input terminal is less than or equal to predetermined current threshold, determine that bridge circuit is defeated The input voltage for entering end currently whether there is positive and negative switching;
In the input voltage, there is currently when positive and negative switching, determine whether the input voltage of input terminal after positive and negative switching is located In positive half period;
When the input voltage of input terminal is in positive half period after positive and negative switching, the first switch unit, second are controlled Switch unit and the shutdown of third switch unit, and the 4th switching means conductive is controlled, and based on pulse change number, pulse The input current of time interval and the input terminal, control second switch unit lead on/off to first switch units alternately Open and the second switch unit be connected when pulsewidth;
When the input voltage of input terminal is in negative half-cycle after positive and negative switching, the first switch unit, second are controlled Switch unit and the shutdown of the 4th switch unit, and the third switching means conductive is controlled, and based on pulse change number, pulse The input current of time interval and the input terminal, control first switch unit lead on/off to second switch units alternately Open and the first switch unit be connected when pulsewidth.
In one embodiment, the pulse change number be 3 times, the pulse interval include the first preset duration, Second preset duration and third preset duration;It is described based on pulse change number, pulse interval and the input terminal Input current, ON/OFF and the second switch unit are led with controlling second switch unit, first switch units alternately The step of pulsewidth when logical includes:
The first input current based on the input terminal in the first preset duration calculates the first pulsewidth;
Reach first preset duration in the conducting duration of the 4th switch unit, is controlled in first pulsewidth The second switch unit conducting;
When the conducting duration of the second switch unit reaches first pulsewidth, in the second preset duration internal control The first switch unit conducting, second switch unit shutdown are made, and based on the input in second preset duration Second input current at end calculates the second pulsewidth;
When the conducting duration of the first switch unit reaches second preset duration, in the second pulsewidth internal control Make the second switch unit conducting, first switch unit shutdown;
When the conducting duration of the second switch unit reaches second pulsewidth, in the third preset duration internal control The first switch unit conducting, second switch unit shutdown are made, and based on the input in the third preset duration The third input current at end calculates third pulsewidth;
When the conducting duration of the first switch unit reaches the third preset duration, in the third pulsewidth internal control Make the second switch unit conducting, first switch unit shutdown;
When the conducting duration of the second switch unit reaches the third pulsewidth, controls the first switch unit and lead Logical, the described second switch unit shutdown.
In one embodiment, first input current based on the input terminal in the first preset duration calculates the first arteries and veins Wide step includes:
Obtain the corresponding default maximum pulse width of first pulsewidth and corresponding first predetermined current, default minimum pulse width and Corresponding second predetermined current, and preset based on the default maximum pulse width, the first predetermined current, default minimum pulse width, second Electric current and first input current calculate first pulsewidth according to linear interpolation algorithm.
In one embodiment, when the conducting duration in the second switch unit reaches the third pulsewidth, control After the step of first switch unit conducting, second switch unit shutdown, further include:
When detecting that the current input current of the input terminal reaches 0, the first switch unit shutdown is controlled.
In one embodiment, the input electricity based on pulse change number, pulse interval and the input terminal Stream, when ON/OFF and the first switch unit are connected with controlling first switch unit, second switch units alternately The step of pulsewidth includes:
The 4th input current based on the input terminal in the first preset duration calculates the 4th pulsewidth;
Reach first preset duration in the conducting duration of the 4th switch unit, is controlled in the 4th pulsewidth The first switch unit conducting;
When the conducting duration of the first switch unit reaches four pulsewidth, in the second preset duration internal control The second switch unit conducting, first switch unit shutdown are made, and based on the input in second preset duration 5th input current at end calculates the 5th pulsewidth;
When the conducting duration of the second switch unit reaches five preset duration, in the 5th pulsewidth internal control Make the first switch unit conducting, second switch unit shutdown;
When the conducting duration of the first switch unit reaches five pulsewidth, in the third preset duration internal control The second switch unit conducting, first switch unit shutdown are made, and based on the input in the third preset duration 6th input current at end calculates the 6th pulsewidth;
When the conducting duration of the second switch unit reaches the third preset duration, in the 6th pulsewidth internal control Make the first switch unit conducting, second switch unit shutdown;
When the conducting duration of the first switch unit reaches six pulsewidth, controls the second switch unit and lead Logical, the described first switch unit shutdown.
In one embodiment, when the conducting duration in the first switch unit reaches six pulsewidth, control After the step of second switch unit conducting, first switch unit shutdown, further include:
When detecting that the current input current of the input terminal reaches 0, the second switch unit shutdown is controlled.
In one embodiment, the pulse width control method further includes:
When the input current of the bridge circuit input terminal is more than predetermined current threshold, the first switch is controlled respectively Unit, second switch unit, third switch unit and the 4th switch unit shutdown.
In addition, to achieve the above object, the present invention also provides a kind of air conditioners, which is characterized in that the air conditioner includes: It above-mentioned totem pfc circuit, memory, processor and is stored on the memory and can run on the processor Pulse-width controlled program, the pulse-width controlled program realize pulse-width controlled side described in any one of the above embodiments when being executed by the processor The step of method.
In addition, to achieve the above object, the present invention also provides a kind of storage mediums, which is characterized in that the storage medium On be stored with pulse-width controlled program, the pulse-width controlled program realizes pulsewidth control described in any one of the above embodiments when being executed by processor The step of method processed.
When the present invention is less than or equal to predetermined current threshold by the input current in bridge circuit input terminal, control module According to the input voltage and input current of bridge circuit input terminal, the on off state of each switch unit and each switch are controlled Pulsewidth when unit is connected, realizes while reducing each switch unit on-off times, according to input voltage and input electricity Stream is that each switch unit selects suitable pulsewidth, can in the current harmonics requirement for meeting totem pfc circuit, improve totem Under the premise of the power factor of column pfc circuit, on-off times are reduced, to reduce the number of short circuit current flow, and then are being reduced Reduce switching loss in circuit while idle work power, improves the efficiency of totem pfc circuit.
Description of the drawings
Fig. 1 is the structural schematic diagram of air conditioner in the hardware running environment that the embodiment of the present invention is related to;
Fig. 2 is the electrical block diagram of one embodiment of totem pfc circuit of the present invention;
Fig. 3 is the flow diagram of pulse width control method first embodiment of the present invention;
Fig. 4 be pulse width control method second embodiment of the present invention in be based on pulse change number, pulse interval and The input current of the input terminal, control second switch unit, first switch units alternately ground ON/OFF and described the The refinement flow diagram of the step of pulsewidth when two switching means conductives;
Fig. 5 is the driving pulse of AC supply voltage Vs, circuital current Is and switch unit Q1~Q4 in the present invention The schematic diagram of time change;
Fig. 6 be pulse width control method 3rd embodiment of the present invention in be based on pulse change number, pulse interval and The input current of the input terminal, control first switch unit, second switch units alternately ground ON/OFF and described the The refinement flow diagram of the step of pulsewidth when one switching means conductive.
Drawing reference numeral explanation:
The embodiments will be further described with reference to the accompanying drawings for the realization, the function and the advantages of the object of the present invention.
Specific implementation mode
It should be appreciated that the specific embodiments described herein are merely illustrative of the present invention, it is not intended to limit the present invention.
As shown in Figure 1, in the hardware running environment that Fig. 1, which is the embodiment of the present invention, to be related to air conditioner structural representation Figure.
As shown in Figure 1, the air conditioner may include:Processor 1001, such as CPU, network interface 1004, user interface 1003, memory 1005, communication bus 1002.Wherein, communication bus 1002 is for realizing the connection communication between these components. User interface 1003 may include display screen (Display), input unit such as keyboard (Keyboard), optional user interface 1003 can also include standard wireline interface and wireless interface.Network interface 1004 may include optionally that the wired of standard connects Mouth, wireless interface (such as WI-FI interfaces).Memory 1005 can be high-speed RAM memory, can also be stable memory (non-volatile memory), such as magnetic disk storage.Memory 1005 optionally can also be independently of aforementioned processor 1001 storage device.
Optionally, air conditioner can also include camera, RF (Radio Frequency, radio frequency) circuit, sensor, sound Frequency circuit, WiFi module etc..Wherein, sensor such as optical sensor, motion sensor and other sensors.Certainly, empty Device is adjusted to can also configure the other sensors such as gyroscope, barometer, hygrometer, thermometer, infrared sensor, it is no longer superfluous herein It states.
It will be understood by those skilled in the art that air conditioner structure shown in Fig. 1 does not constitute the restriction to air conditioner, it can To include either combining certain components or different components arrangement than illustrating more or fewer components.
As shown in Figure 1, as may include that operating system, network are logical in a kind of memory 1005 of computer storage media The changeover program of letter module, Subscriber Interface Module SIM and pfc circuit.
In air conditioner shown in Fig. 1, network interface 1004 be mainly used for connect background server, with background server into Row data communication;User interface 1003 is mainly used for connecting client (user terminal), with client into row data communication;And it handles Device 1001 can be used for calling the changeover program of the pfc circuit stored in memory 1005.
In the present embodiment, air conditioner includes:Totem pfc circuit, memory 1005, processing in the embodiment of the present invention Device 1001 and it is stored in the pulse-width controlled program that can be run on the memory 1005 and on the processor 1001, wherein When processor 1001 calls the pulse-width controlled program stored in memory 1005, pulse-width controlled provided by the embodiments of the present application is executed Method.
The present invention also provides a kind of totem pfc circuits, implement for totem pfc circuit one of the present invention with reference to Fig. 2, Fig. 2 The electrical block diagram of example.
In the present embodiment, totem pfc circuit includes:Bridge circuit 20, reactor L, bus capacitor C and control module 10。
Bridge circuit 20, which is equipped with, is connected as the multiple switch unit of bridge shape, the input terminal of the bridge circuit 20 with exchange Power supply is connected, and output end is connected with load.
Reactor L is arranged between the bridge circuit 20 and the AC power.Reactor L savings is supplied from AC power The electric power given as energy, by discharge the energy realize totem pfc circuit boosting and power factor improvement.
It is electrically connected with the output end of bridge circuit 20 after bus capacitor C is in parallel with load.
Control module 10 is used for when the input current of 20 input terminal of the bridge circuit is more than predetermined current threshold, control Each switch unit shutdown in bridge circuit 20;And it is less than or equal in the input current of 20 input terminal of the bridge circuit default When current threshold, which controls each switch according to the input voltage and input current of 20 input terminal of bridge circuit The pulsewidth when on off state of unit and each switching means conductive.
In the present embodiment, in totem pfc circuit operational process, control module 10 can obtain bridge circuit 20 in real time The input current of input terminal, and judge whether the input current got is more than predetermined current threshold, wherein it is big in input current When predetermined current threshold, which controls each switch unit shutdown in bridge circuit 20, to realize the totem The overcurrent protection of pfc circuit;When input current is less than or equal to predetermined current threshold, which obtains bridge circuit The input voltage Vs and input current of 20 input terminals, and according to the input voltage and input current of 20 input terminal of bridge circuit, control The pulsewidth when on off state of each switch unit and each switching means conductive is made, and then is opened reducing each switch unit While closing number, it is that each switch unit selects suitable pulsewidth according to input voltage and input current, can schemes meeting Under the premise of rising the current harmonics requirement of column pfc circuit, the power factor of improvement totem pfc circuit, on-off times are reduced, with Reduce switching loss and improves efficiency.
Wherein, predetermined current threshold can be rationally arranged according to the demand of totem pfc circuit.
Further, in one embodiment, bridge circuit 20 includes first switch unit Q1, second switch unit Q2, the Three switch unit Q3 and the 4th switch unit Q4.
First switch unit Q1 and second switch unit Q2 are connected in series to form the first branch, third switch unit Q3 and the Four switch unit Q4 are connected in series to form the second branch, and the first branch is connected in parallel to form the bridge circuit with the second branch 20。
First switch unit Q1 is electrically connected via reactor L with AC power with the tie point of second switch unit Q2;The Three switch unit Q3 are electrically connected with the tie point of the 4th switch unit Q4 with AC power.First switch unit Q1 is switched with third The tie point of unit Q3 is electrically connected with the anode of bus capacitor C;The tie point of second switch unit Q2 and the 4th switch unit Q4 It is electrically connected with the cathode of bus capacitor C.
Specifically, first switch unit Q1, second switch unit Q2, third switch unit Q3 and the 4th switch unit Q4 are equal Can be that MOSFET (partly lead by Metal-Oxide-Semiconductor Field-Effect Transistor, metal oxide Body field-effect transistor), such as super node MOSFET or SiC-MOSFET.Preferably, the source electrode of first switch unit Q1 and The drain electrode of two switch unit Q2 is electrically connected, and tie point is electrically connected via reactor L with AC power;Third switch unit Q3's Source electrode is electrically connected with the drain electrode of the 4th switch unit Q4, and tie point is electrically connected with AC power;The leakage of first switch unit Q1 Pole is electrically connected with the drain electrode of third switch unit Q3, and tie point is electrically connected with the anode of bus capacitor C;Second switch unit Q2 Source electrode be electrically connected with the source electrode of the 4th switch unit Q4, tie point is electrically connected with the cathode of bus capacitor C.
There is parasitic diode in the inside of first switch unit Q1.Parasitic diode is in the source of first switch unit Q1 The part of existing pn-junction between pole and drain electrode.The saturation voltage of first switch unit Q1 is (between the drain-source under on-state Voltage) less than the positive voltage drop of parasitic diode.Flowed through in the source drain of first switch unit Q1 as a result, electric current with It flows through electric current in parasitic diode to compare, voltage drop becomes smaller, or even can reduce conduction losses.It is easy-to-understand to and says, is connecing Flowed through in the first switch unit Q1 of logical state electric current in the parasitic diode in the first switch unit Q1 of off-state It flows through electric current to compare, conduction losses is made to become smaller.In addition, could also say that for other switch unit Q2~Q4 same.
Further, control module 10 includes:Current detecting unit 12, alternating voltage detection unit 13 and control unit 11。
The current detecting unit 12 is electrically connected with the input terminal of bridge circuit 20, the input terminal for detecting bridge circuit 20 Input current;The alternating voltage detection unit 13 is electrically connected with the input terminal of bridge circuit 20, for detecting bridge circuit 20 Input terminal input voltage.
The control unit 11 is electrically connected with current detecting unit 12 and the alternating voltage detection unit 13 respectively.The control Unit 11 is used to, when the input current that current detecting unit 12 detects is less than or equal to predetermined current threshold, be examined according to electric current The input current that unit 12 detects and the input voltage that the alternating voltage detection unit 13 detects are surveyed, the electricity is controlled The on off state of each switch unit and pulsewidth when each switching means conductive in bridge circuit 20.
Preferably, in another embodiment, control module 10 further includes:Drive protection location 14 and driving unit 15.
The driving protection location 14 is electrically connected with current detecting unit 12 and the driving unit 15 respectively, for described When the input current that current detecting unit 12 detects is more than predetermined current threshold, it is single to the driving to send shutdown control signal Member 15.The driving unit 15 is used to be closed according to each switch unit in the shutdown control signal control bridge circuit 20 received It is disconnected, to realize the overcurrent protection of totem pfc circuit.
The input current that the control unit 11 is additionally operable to detect in the current detecting unit 12 is less than or equal to default When current threshold, the input current and alternating voltage detection unit 13 that are detected according to current detecting unit 12 detect defeated Enter voltage and generate state control signal, and state control signal is sent to driving unit 15;The driving unit 15 is additionally operable to root The on off state of each switch unit and each switch in the bridge circuit 20 are controlled according to the state control signal received Pulsewidth when unit is connected.
In other embodiments, which further includes busbar voltage detection unit 16, the busbar voltage detection list Member 16 is electrically connected with the input terminal of load, the busbar voltage for detecting the load.The busbar voltage detection unit 16 and control Unit 11 processed is electrically connected, which is additionally operable to when the busbar voltage of the load detected is in outside preset range, is sent out Send shutdown control signal to driving unit 15, which is used for according to the shutdown control signal control electric bridge electricity received Each switch unit shutdown in road 20, to realize overvoltage/under-voltage protection of the middle load of totem pfc circuit.
The totem pfc circuit that the present embodiment proposes, by being less than or waiting in the input current of 20 input terminal of bridge circuit When predetermined current threshold, control module 10 controls each according to the input voltage and input current of 20 input terminal of bridge circuit The pulsewidth when on off state of switch unit and each switching means conductive realizes and is reducing each switch unit switch While number, it is that each switch unit selects suitable pulsewidth according to input voltage and input current, totem can be being met Under the premise of the current harmonics of pfc circuit requires, improves the power factor of totem pfc circuit, on-off times are reduced, to reduce The number of short circuit current flow, and then reduce switching loss while idle work power in reducing circuit, improve totem PFC The efficiency of circuit.
The present invention also provides a kind of pulse width control methods, implement for pulse width control method first of the present invention with reference to Fig. 3, Fig. 3 The flow diagram of example.
In the present embodiment, which is applied to the totem pfc circuit of above-described embodiment.
The pulse width control method includes the following steps:
Step S100 determines electric bridge when the input current of bridge circuit input terminal is less than or equal to predetermined current threshold The input voltage of circuit input end currently whether there is positive and negative switching;
In the present embodiment, the control module of totem pfc circuit can acquire the input electricity of bridge circuit input terminal in real time Stream, when getting the input current of bridge circuit input terminal, which determines the input current of bridge circuit input terminal Whether predetermined current threshold is more than, if the input current of bridge circuit input terminal is less than or equal to predetermined current threshold, it is determined that The input voltage of bridge circuit input terminal currently whether there is positive and negative switching.
It specifically, can be by driving protection location real if control module includes driving protection location and driving unit When acquire bridge circuit input terminal input current.It is less than or equal to predetermined current threshold in the input current of bridge circuit input terminal When value, the input voltage (i.e. AC supply voltage Vs) that alternating voltage detection unit detects is obtained in real time, and judge the exchange Whether supply voltage Vs has carried out positive and negative switching (whether having reached zero passage).
Step S200 determines the input of input terminal after positive and negative switching in the input voltage there is currently when positive and negative switching Whether voltage is in positive half period;
In the present embodiment, in input voltage the input of input terminal after positive and negative switching is determined there is currently when positive and negative switching Whether voltage is in positive half period, that is, determines whether the input voltage of currently detected input terminal is more than 0V, in input voltage When more than 0V, the input voltage of input terminal is in positive half period after positive and negative switching, otherwise, the input electricity of input terminal after positive and negative switching Pressure is in negative half-cycle.
Step S300 controls the first switch when input voltage of input terminal is in positive half period after positive and negative switching Unit Q1, second switch unit Q2 and the Q3 shutdowns of third switch unit, control the 4th switch unit Q4 conductings, and be based on arteries and veins Rush the input current of change frequency, pulse interval and the input terminal, control second switch unit Q2, first switch list Pulsewidth when first Q1 is alternately turned on/disconnects and the second switch unit Q2 is connected;
Step S400 controls the first switch when input voltage of input terminal is in negative half-cycle after positive and negative switching Unit Q1, second switch unit Q2 and the 4th switch unit Q4 shutdowns, and the third switch unit Q3 conductings are controlled, and be based on The input current of pulse change number, pulse interval and the input terminal, control first switch unit Q1, second switch Pulsewidth when unit Q2 is alternately turned on/disconnects and the first switch unit Q1 is connected.
Wherein, pulse change number and pulse interval can be prestored, which can be first Switch unit Q1 and second switch unit Q2 is by turning off to the change frequency of conducting or the change frequency by being conducted to shutdown. When the input voltage of input terminal is in positive half period after positive and negative switching, pulse interval refers to second switch unit Q2 from pass The disconnected moment is to the time interval between turn-on instant;When the input voltage of input terminal is in negative half-cycle after positive and negative switching, arteries and veins It refers to first switch unit Q1 from the shutdown moment to the time interval between turn-on instant to rush time interval;The pulse interval Number it is consistent with pulse change number.
For example, when pulse change number is 2, pulse interval includes first time interval and the second time interval. If the input voltage of input terminal is in positive half period after positive and negative switching, control module controls first switch unit Q1 shutdowns, the When two switch unit Q2 shutdowns, third switch unit Q3 shutdowns, the 4th switch unit Q4 conductings, according to defeated in first time interval The input current for entering end calculates a pulsewidth (high level duration), when the conducting duration of the 4th switch unit Q4 reaches first Between when being spaced, the Q2 conductings of second switch unit are controlled in the pulsewidth, reach the arteries and veins in the conducting duration of second switch unit Q2 When wide, first switch unit Q1 conductings, the Q2 shutdowns of second switch unit are controlled in the second time interval, and be based on for the second time The input current of input terminal calculates another pulsewidth in interval, reaches the second time interval in the conducting duration of first switch unit Q1 When, second switch unit Q2 conductings, the Q1 shutdowns of first switch unit are controlled in another pulsewidth, then in second switch unit Q2 Conducting duration when reaching another pulsewidth, control first switch unit Q1 conductings, the Q2 shutdowns of second switch unit, then prison in real time The current input current of input terminal is surveyed, when detecting that the current input current of input terminal reaches 0 and drops to 0, first is controlled and opens Close unit Q1 shutdowns.
If the input voltage of input terminal is in negative half-cycle after positive and negative switching, control module controls first switch unit Q1 When shutdown, second switch unit Q2 shutdowns, the 4th switch unit Q4 shutdowns, the Q3 conductings of third switch unit, according at the first time The input current of input terminal calculates a pulsewidth (high level duration) in interval, is up in the conducting of third switch unit Q3 When to first time interval, the Q1 conductings of first switch unit are controlled in the pulsewidth, in the conducting duration of first switch unit Q1 When reaching the pulsewidth, second switch unit Q2 conductings, the Q1 shutdowns of first switch unit are controlled in the second time interval, and be based on The input current of input terminal calculates another pulsewidth in second time interval, reaches second in the conducting duration of second switch unit Q2 When time interval, first switch unit Q1 conductings, the Q2 shutdowns of second switch unit are controlled in another pulsewidth, is then opened first When the conducting duration of pass unit Q1 reaches another pulsewidth, control second switch unit Q2 conductings, the Q1 shutdowns of first switch unit, and The current input current of real-time monitor input terminal afterwards, when detecting that the current input current of input terminal reaches 0 and drops to 0, control Second switch unit Q2 shutdowns processed.
When the input voltage of input terminal is in positive half period after positive and negative switching, third switch unit Q3 shutdowns, the 4th open Unit Q4 is closed, if second switch unit Q2 conductings, the Q1 shutdowns of first switch unit, totem pfc circuit carries out improvement work(at this time The operation of rate factor, the circuital current is (input current of bridge circuit input terminal) for flowing through totem pfc circuit are short circuit electricity Stream, and short circuit current sequence flows through AC power-the 4th switch unit Q4- alternating currents of reactor L- second switch units Q2- Source, at this time reactor L energy is put aside by short circuit current.Correspondingly, the input voltage of input terminal is in negative after positive and negative switching When the half period, third switch unit Q3 conductings, the 4th switch unit Q4 shutdowns, if second switch unit Q2 shutdowns, first switch Unit Q1 is connected, and totem pfc circuit improve the operation of power factor at this time, flows through the circuit electricity of totem pfc circuit It is short circuit current to flow is (input current of bridge circuit input terminal), and short circuit current sequence flows through AC power-third and opens Unit Q3- first switch unit Q1- reactor L- AC powers are closed, reactor L puts aside energy by short circuit current at this time.
When the input voltage of input terminal is in positive half period after positive and negative switching, third switch unit Q3 shutdowns, the 4th open Unit Q4 conductings are closed, if second switch unit Q2 shutdowns, the Q1 conductings of first switch unit, totem pfc circuit carries out same at this time Rectifying action is walked, according to AC power-reactor L- first switch unit Q1- bus capacitors C- the 4th in totem pfc circuit Circuital current is (input current of bridge circuit input terminal) is flowed through in the current path of switch unit Q4- AC power sequences, The energy put aside in reactor L is discharged to bus capacitor C, is boosted to the DC voltage of bus capacitor C.Correspondingly, When the input voltage of input terminal is in negative half-cycle after positive and negative switching, third switch unit Q3 conductings, the 4th switch unit Q4 are closed Disconnected, if second switch unit Q2 conductings, the Q1 shutdowns of first switch unit, totem pfc circuit synchronizes rectifying action at this time, According to AC power-third switch unit Q3- bus capacitor C- second switch unit Q2- reactors L- in totem pfc circuit Circuital current is (input current of bridge circuit input terminal) is flowed through in the current path of AC power sequence, to bus capacitor C The energy put aside in reactor L is discharged, is boosted to the DC voltage of bus capacitor C.
By above-mentioned short circuit current, the distortion of current waveform can be reduced, make current waveform close to sine wave, Jin Erneng Enough improve the power factor of totem pfc circuit, and the higher hamonic wave associated with higher harmonic current can be inhibited.Also, By calculating the pulsewidth of second switch unit Q2 or first switch unit Q1 according to the busbar voltage of load, figure can be rationally adjusted The duration for rising column pfc circuit short circuit currents rationally controls time of each switch conduction/shutdown according to pulse change number Number can reduce the conduction losses of switch unit, reduce switching loss, improve efficiency.
For example, when load is the compressor of air conditioner, with the rising of rotating speed, the induced voltage of compressor is got higher, pressure Contracting machine becomes difficult to drive, but by being alternately carried out above-mentioned " power-factor improvement action " and " synchronous rectification action " It boosts, can improve the permission limit of motor speed.
It should be noted that when pulse change number is other preset values, the control of step S300 and step S400 Control process when process and pulse change number are 2 is similar, and details are not described herein.
Further, in another embodiment, pulse width control method further includes:In the input electricity of the bridge circuit input terminal When stream is more than predetermined current threshold, the first switch unit Q1, second switch unit Q2, third switch unit Q3 are controlled respectively And the 4th switch unit Q4 shutdowns.
In the present embodiment, in totem pfc circuit operational process, control module can obtain sampling bridge circuit in real time The input current of input terminal, and judge whether the electric current of the input current of the bridge circuit input terminal got is more than predetermined current Threshold value, wherein when the input current of bridge circuit input terminal is more than predetermined current threshold, which controls bridge circuit In the shutdown of each switch unit, to realize the overcurrent protection of the totem pfc circuit.
Further, in another embodiment, which further includes:The busbar voltage of detection load in real time, When the busbar voltage of the load detected is in outside preset range, each switch unit shutdown in bridge circuit is controlled, that is, is distinguished The first switch unit Q1, second switch unit Q2, third switch unit Q3 and the 4th switch unit Q4 shutdowns are controlled, To realize overvoltage/under-voltage protection of the middle load of totem pfc circuit.
The pulse width control method that the present embodiment proposes is less than or equal to pre- by the input current in bridge circuit input terminal If when current threshold, determining that the input voltage of bridge circuit input terminal currently whether there is positive and negative switching, then in the input Voltage then exists there is currently when positive and negative switching, determining whether the input voltage of input terminal after positive and negative switching is in positive half period When the input voltage of input terminal is in positive half period after positive and negative switching, the first switch unit Q1, second switch unit are controlled Q2 and third switch unit Q3 shutdowns, and control the 4th switch unit Q4 conductings, and when based on pulse change number, pulse Between be spaced and the input current of the input terminal, control second switch unit Q2, first switch unit Q1 are alternately turned on/break It opens and the pulsewidth when second switch unit Q2 is connected, or the input voltage of input terminal is in negative after positive and negative switching When the half period, the first switch unit Q1, second switch unit Q2 and the 4th switch unit Q4 shutdowns are controlled, and described in control The Q3 conductings of third switch unit, and the input current based on pulse change number, pulse interval and the input terminal, control When first switch unit Q1 processed, second switch unit Q2 are alternately turned on/disconnect and the first switch unit Q1 is connected Pulsewidth;By calculating the pulsewidth of second switch unit Q2 or first switch unit Q1, Neng Gouhe according to the input current of input terminal The duration of reason adjustment totem pfc circuit short circuit currents, improve the power factor of totem pfc circuit, and can Inhibition and the associated higher hamonic wave of higher harmonic current, each switch conduction/shutdown is rationally controlled according to pulse change number Number can rationally take into account the improvement of power factor in totem pfc circuit and open to reduce the number of short circuit current flow Loss is closed, and then reduces switching loss while idle work power in reducing circuit, improves the efficiency of totem pfc circuit.
Based on first embodiment, the second embodiment of pulse width control method of the present invention is proposed, with reference to Fig. 4, in the present embodiment In, pulse change number is 3 times, and the pulse interval includes that the first preset duration, the second preset duration and third are default Duration.Wherein, the first preset duration, the second preset duration and third preset duration can be according to the need of the totem pfc circuit It asks and is reasonably arranged.
Step S300 includes;
Step S310, the first input current based on the input terminal in the first preset duration calculate the first pulsewidth;
In the present embodiment, the first switch unit Q1, second switch unit Q2 and third switch unit Q3 are being controlled When turning off, and controlling the 4th switch unit Q4 conductings, the first input current of input terminal in the first preset duration is obtained, and The first pulsewidth is calculated according to first input current afterwards, wherein can be in the first preset duration to the input current of input terminal It carries out stochastical sampling and obtains the first input current, alternatively, multiple sampling instants are arranged in the first preset duration, obtain multiple adopt Sample moment corresponding input current, is then calculated the mean value of the corresponding input current of multiple sampling instants, which is made For the first input current.
Specifically, step S310 includes:Obtain the corresponding default maximum pulse width of first pulsewidth and corresponding first Predetermined current, default minimum pulse width and corresponding second predetermined current, and based on the default maximum pulse width, the first default electricity Stream, default minimum pulse width, the second predetermined current and first input current, first arteries and veins is calculated according to linear interpolation algorithm It is wide.
Wherein, can the corresponding default maximum pulse width of the first pulsewidth and correspondence be rationally set previously according to the demand of pfc circuit The first predetermined current, the default parameters such as minimum pulse width and corresponding second predetermined current, when getting the first input current, First pulsewidth is calculated according to linear interpolation algorithm based on the first input current, and then is rationally arranged second switch unit Q2's First pulsewidth, rationally to adjust the duration of totem pfc circuit short circuit currents.
Step S320, when the conducting duration of the 4th switch unit Q4 reaches first preset duration, described The control second switch unit Q2 conductings in first pulsewidth;
In the present embodiment, it is connected by controlling the second switch unit Q2 in the first pulsewidth so that totem PFC Circuit short circuit current flow makes current waveform close to sine wave to reduce the distortion of current waveform, and then can improve totem The power factor of pfc circuit, and the higher hamonic wave associated with higher harmonic current can be inhibited.
Step S330, when the conducting duration of the second switch unit Q2 reaches first pulsewidth, described second The control first switch unit Q1 conductings, second switch unit Q2 shutdowns in preset duration, and it is pre- based on described second If the second input current of the input terminal calculates the second pulsewidth in duration;
In the present embodiment, the acquisition mode of the second input current is similar with the first input current, and details are not described herein. Can be that the calculation similar with the first pulsewidth is arranged in the second pulsewidth.It is preset most it should be noted that the second pulsewidth is corresponding Big pulsewidth, the corresponding predetermined current of default maximum pulse width, the corresponding default minimum pulse width of the second pulsewidth and default minimum pulse width pair The parameters such as the predetermined current answered, can be identical as the parameter of the first pulsewidth, can also be arranged according to the demand of totem pfc circuit Different parameters.
Step S340, when the conducting duration of the first switch unit Q1 reaches second preset duration, described The control second switch unit Q2 conductings, first switch unit Q1 shutdowns in second pulsewidth;
In the present embodiment, by controlling the second switch unit Q2 conductings, first switch unit in the first pulsewidth Q1 is turned off so that totem pfc circuit short circuit current flow makes current waveform close to sine to reduce the distortion of current waveform Wave, and then the power factor of totem pfc circuit can be improved, and high order associated with higher harmonic current can be inhibited humorous Wave.
Step S350, when the conducting duration of the second switch unit Q2 reaches second pulsewidth, in the third The control first switch unit Q1 conductings, second switch unit Q2 shutdowns in preset duration, and it is pre- based on the third If the third input current of the input terminal calculates third pulsewidth in duration;
In the present embodiment, the acquisition mode of third input current is similar with the first input current/second input current, This is repeated no more.Or the calculation similar with the first pulsewidth/second pulsewidth is arranged in third pulsewidth.It needs to illustrate It is the corresponding default maximum pulse width of third width, the corresponding predetermined current of default maximum pulse width, the corresponding default minimum of third pulsewidth The parameters such as pulsewidth and the corresponding predetermined current of default minimum pulse width, can be identical as the parameter of the pulsewidth of the first pulsewidth/second, also may be used Different parameters to be arranged according to the demand of totem pfc circuit.
Step S360, when the conducting duration of the first switch unit Q1 reaches the third preset duration, described The control second switch unit Q2 conductings, first switch unit Q1 shutdowns in third pulsewidth;
In the present embodiment, by controlling the second switch unit Q2 conductings, first switch unit in third pulsewidth Q1 is turned off so that totem pfc circuit short circuit current flow makes current waveform close to sine to reduce the distortion of current waveform Wave, and then the power factor of totem pfc circuit can be improved, and high order associated with higher harmonic current can be inhibited humorous Wave.
Step S370, when the conducting duration of the second switch unit Q2 reaches the third pulsewidth, control described the One switch unit Q1 conductings, second switch unit Q2 shutdowns.
It is the driving pulse of AC supply voltage Vs, circuital current Is and switch unit Q1~Q4 with reference to Fig. 5, Fig. 5 The schematic diagram of time change, in Fig. 5, T1, T2, T3 are respectively the first preset duration, the second preset duration and third preset duration, D1, D2, D3 are respectively the first pulsewidth, the second pulsewidth, third pulsewidth, in the positive half period of alternating voltage, the 4th switch unit Q4 Conducting, the Q3 shutdowns of third switch unit;After voltage zero-cross delay time T1, the Q2 conductings of second switch unit;Second switch list After first Q2 turn-on times D1, the Q2 shutdowns of second switch unit, the Q1 conductings of first switch unit;First switch unit Q1 turn-on times After T2, the Q1 shutdowns of first switch unit, the Q2 conductings of second switch unit;After second switch unit Q2 turn-on times D2, second opens Close unit Q2 shutdowns, the Q1 conductings of first switch unit;After first switch unit Q1 turn-on times T3, first switch unit Q1 is closed Disconnected, second switch unit Q2 is connected, after turn-on time D3, the Q2 shutdowns of second switch unit, and the Q1 conductings of first switch unit.Such as This, Q1 and Q2 alternate conductions/shutdown 3 times, wherein when second switch unit Q2 is connected, the input current of totem pfc circuit Is (circuital current) rises, and when first switch unit Q1 is connected, input current declines.
Further, in one embodiment, after step s 370, further include:Detecting that the input terminal is current When input current reaches 0, the first switch unit Q1 shutdowns are controlled.
With reference to Fig. 5, first switch unit Q1 is turned off before the positive half period of alternating voltage terminates, can be prevented from busbar Capacitance C flows through adverse current electric current.
The pulse width control method that the present embodiment proposes, by being based on the first input current, the second input current third inputs The first pulsewidth that Current calculation obtains, the second pulsewidth, third pulsewidth, and respectively in the first pulsewidth, the second pulsewidth, third pulsewidth control Second switch unit Q2 processed conducting, the Q1 shutdowns of first switch unit so that the first pulsewidth, the second pulsewidth, totem in third pulsewidth Column pfc circuit respectively flows through the short circuit current of different durations, can rationally adjust totem pfc circuit short circuit currents Duration can improve the power factor of totem pfc circuit to reduce the distortion of current waveform, and can inhibit with The associated higher hamonic wave of higher harmonic current, while reducing switching loss according to pulse change number, improving efficiency, rationally Take into account the power factor of totem pfc circuit.
Based on second embodiment, the 3rd embodiment of pulse width control method of the present invention is proposed, with reference to Fig. 6, in the present embodiment In, step S400 includes;
Step S410, the 4th input current based on the input terminal in the first preset duration calculate the 4th pulsewidth;
Step S420, when the conducting duration of the 4th switch unit Q4 reaches first preset duration, described The control first switch unit Q1 conductings in 4th pulsewidth;
Step S430, when the conducting duration of the first switch unit Q1 reaches four pulsewidth, described second The control second switch unit Q2 conductings, first switch unit Q1 shutdowns in preset duration, and it is pre- based on described second If the 5th input current of the input terminal calculates the 5th pulsewidth in duration;
Step S440, when the conducting duration of the second switch unit Q2 reaches five preset duration, described The control first switch unit Q1 conductings, second switch unit Q2 shutdowns in 5th pulsewidth;
Step S450, when the conducting duration of the first switch unit Q1 reaches five pulsewidth, in the third The control second switch unit Q2 conductings, first switch unit Q1 shutdowns in preset duration, and it is pre- based on the third If the 6th input current of the input terminal calculates the 6th pulsewidth in duration;
Step S460, when the conducting duration of the second switch unit Q2 reaches the third preset duration, described The control first switch unit Q1 conductings, second switch unit Q2 shutdowns in 6th pulsewidth;
Step S470, when the conducting duration of the first switch unit Q1 reaches six pulsewidth, control described the Two switch unit Q2 conductings, first switch unit Q1 shutdowns.
In the present embodiment, the acquisition mode of the four/five/six input current is similar with the first/bis-/tri- input currents, This is repeated no more.Or the calculation similar with the first/bis-/tri- pulsewidths is arranged in the four/five/six pulsewidth.It needs to illustrate , the corresponding default maximum pulse width of the four/five/six pulsewidth, the corresponding predetermined current of default maximum pulse width, the four/five/six arteries and veins The parameters such as the corresponding default minimum pulse width of width and the corresponding predetermined current of default minimum pulse width, can be with the first/bis-/tri- pulsewidths Parameter is identical, and different parameters can also be arranged according to the demand of totem pfc circuit.
In the present embodiment, by controlling the first switch unit Q1 in the pulsewidth of the pulsewidth of the 4th pulsewidth/the 5th/the 6th Conducting, the Q2 shutdowns of second switch unit so that totem pfc circuit short circuit current flow can rationally adjust totem PFC electricity The duration of road short circuit currents, and then the power factor of totem pfc circuit can be improved.
With reference to Fig. 5, in the negative half-cycle of alternating voltage, the 4th switch unit Q4 shutdowns, the Q3 conductings of third switch unit; After voltage zero-cross delay time T1, the Q1 conductings of first switch unit;After first switch unit Q1 turn-on times D1, second switch list First Q2 conductings, the Q1 shutdowns of first switch unit;After second switch unit Q2 turn-on times T2, the Q2 shutdowns of second switch unit, the One switch unit Q1 conductings;After first switch unit Q1 turn-on times D2, the Q1 shutdowns of first switch unit, second switch unit Q2 Conducting;After second switch unit Q2 turn-on times T3, second switch unit Q2 shutdown, first switch unit Q1 conductings, when conducting Between after D3, first switch unit Q1, the Q2 conductings of second switch unit.In this way, Q1 and Q2 alternate conductions/shutdown 3 times, wherein When the Q2 conductings of second switch unit, the input current Is (circuital current) of totem pfc circuit rises, in first switch unit Q1 When conducting, input current declines.
Further, in one embodiment, after step S470, further include:Detecting that the input terminal is current When input current reaches 0, the second switch unit Q2 shutdowns are controlled.
With reference to Fig. 5, second switch unit Q2 is turned off before the negative half-cycle of alternating voltage terminates, can be prevented from busbar Capacitance C flows through adverse current electric current.
The pulse width control method that the present embodiment proposes, by being based on the 4th input current, the 5th input current third inputs The 4th pulsewidth, the 5th pulsewidth, the 6th pulsewidth that Current calculation obtains, and respectively in the first pulsewidth, the 5th pulsewidth, the 6th pulsewidth control First switch unit Q1 processed conducting, the Q2 shutdowns of second switch unit so that the 4th pulsewidth, the 5th pulsewidth, totem in the 6th pulsewidth Column pfc circuit respectively flows through the short circuit current of different durations, can rationally adjust totem pfc circuit short circuit currents Duration can improve the power factor of totem pfc circuit to reduce the distortion of current waveform, and can inhibit with The associated higher hamonic wave of higher harmonic current, while reducing switching loss according to pulse change number, improving efficiency, rationally Take into account the power factor of totem pfc circuit.
In addition, the embodiment of the present invention also proposes a kind of storage medium, i.e. computer readable storage medium, the storage medium On be stored with pulse-width controlled program, the pulse-width controlled program realizes the step of above-mentioned pulse width control method when being executed by processor Suddenly.
It should be noted that herein, the terms "include", "comprise" or its any other variant are intended to non-row His property includes, so that process, method, article or system including a series of elements include not only those elements, and And further include other elements that are not explicitly listed, or further include for this process, method, article or system institute it is intrinsic Element.In the absence of more restrictions, the element limited by sentence "including a ...", it is not excluded that including this There is also other identical elements in the process of element, method, article or system.
The embodiments of the present invention are for illustration only, can not represent the quality of embodiment.
Through the above description of the embodiments, those skilled in the art can be understood that above-described embodiment side Method can add the mode of required general hardware platform to realize by software, naturally it is also possible to by hardware, but in many cases The former is more preferably embodiment.Based on this understanding, technical scheme of the present invention substantially in other words does the prior art Going out the part of contribution can be expressed in the form of software products, which is stored in one as described above In storage medium (such as ROM/RAM, magnetic disc, CD), including some instructions use so that a station terminal equipment (can be mobile phone, Computer, server, air conditioner or network equipment etc.) execute method described in each embodiment of the present invention.
It these are only the preferred embodiment of the present invention, be not intended to limit the scope of the invention, it is every to utilize this hair Equivalent structure or equivalent flow shift made by bright specification and accompanying drawing content is applied directly or indirectly in other relevant skills Art field, is included within the scope of the present invention.

Claims (13)

1. a kind of totem pfc circuit, which is characterized in that the totem pfc circuit includes:
Bridge circuit, the bridge circuit are equipped with the multiple switch unit for being connected as bridge shape, the input of the bridge circuit End is connected with AC power, and output end is connected with load;
Reactor, the reactor are arranged between the bridge circuit and the AC power;
Bus capacitor is electrically connected after the bus capacitor is in parallel with the load with the output end of the bridge circuit;
Control module, the control module are used to be more than predetermined current threshold in the input current of the bridge circuit input terminal When, control each switch unit shutdown in the bridge circuit;And be less than in the input current of the bridge circuit input terminal or When equal to predetermined current threshold, according to the input voltage and input current of the bridge circuit input terminal, it is single to control each switch The pulsewidth when on off state of member and each switching means conductive.
2. totem pfc circuit as described in claim 1, which is characterized in that the bridge circuit include first switch unit, Second switch unit, third switch unit and the 4th switch unit;
The first switch unit and the second switch unit are connected in series to form the first branch, the third switch unit with 4th switch unit is connected in series to form the second branch, and the first branch is connected in parallel to form the electricity with the second branch Bridge circuit;
The tie point of the first switch unit and the second switch unit is electric via the reactor and the AC power Connection;The third switch unit is electrically connected with the tie point of the 4th switch unit with the AC power;
The first switch unit is electrically connected with the tie point of the third switch unit with the anode of the bus capacitor;It is described Second switch unit is electrically connected with the tie point of the 4th switch unit with the cathode of the bus capacitor.
3. totem pfc circuit as described in claim 1, which is characterized in that the control module includes:
Current detecting unit, the current detecting unit are electrically connected with the input terminal of the bridge circuit, for detecting the electricity The input current of the input terminal of bridge circuit;
Alternating voltage detection unit, the alternating voltage detection unit is electrically connected with the input terminal of the bridge circuit, for examining Survey the input voltage of the input terminal of bridge circuit;
Described control unit is electrically connected with the current detecting unit and the alternating voltage detection unit respectively, for described When the input current that current detecting unit detects is less than or equal to predetermined current threshold, detected according to the current detecting unit To the input voltage that detects of input current and the alternating voltage detection unit, control each in the bridge circuit open Close the pulsewidth when on off state of unit and each switching means conductive.
4. totem pfc circuit as claimed in claim 3, which is characterized in that the control module further includes:Driving protection is single Member and driving unit;
Protection location, the driving protection location is driven to be electrically connected, be used for current detecting unit and the driving unit respectively When the input current that the current detecting unit detects is more than predetermined current threshold, shutdown control signal is sent to the drive Moving cell;
The driving unit is used to control each switch unit in the bridge circuit according to the shutdown control signal received and close It is disconnected;
The input current that described control unit is additionally operable to detect in the current detecting unit is less than or equal to predetermined current threshold When value, input that the input current and the alternating voltage detection unit that are detected according to the current detecting unit detect Voltage generates state control signal, and the state control signal is sent to the driving unit;
The driving unit is additionally operable to control each switch unit in the bridge circuit according to the state control signal received On off state and pulsewidth when each switching means conductive.
5. a kind of pulse width control method, which is characterized in that be applied to the totem pfc circuit described in claim 2, the pulsewidth Control method includes the following steps:
When the input current of the bridge circuit input terminal is less than or equal to predetermined current threshold, bridge circuit input terminal is determined Input voltage currently whether there is positive and negative switching;
In the input voltage, whether there is currently when positive and negative switching, determine the input voltage of input terminal after positive and negative switching in just Half period;
When the input voltage of input terminal is in positive half period after positive and negative switching, the first switch unit, second switch are controlled Unit and the shutdown of third switch unit, control the 4th switching means conductive, and based on pulse change number, between the burst length Every and the input terminal input current, control second switch unit, first switch units alternately ground ON/OFF, and Pulsewidth when the second switch unit conducting;
When the input voltage of input terminal is in negative half-cycle after positive and negative switching, the first switch unit, second switch are controlled Unit and the shutdown of the 4th switch unit, control the third switching means conductive, and based on pulse change number, between the burst length Every and the input terminal input current, control first switch unit, second switch units alternately ground ON/OFF, and Pulsewidth when the first switch unit conducting.
6. pulse width control method as claimed in claim 5, which is characterized in that the pulse change number is 3 times, the pulse Time interval includes the first preset duration, the second preset duration and third preset duration;It is described to be based on pulse change number, pulse The input current of time interval and the input terminal, control second switch unit lead on/off to first switch units alternately Open and the second switch unit be connected when pulsewidth the step of include:
The first input current based on the input terminal in the first preset duration calculates the first pulsewidth;
When the conducting duration of the 4th switch unit reaches first preset duration, institute is controlled in first pulsewidth State the conducting of second switch unit;
When the conducting duration of the second switch unit reaches first pulsewidth, institute is controlled in second preset duration The conducting of first switch unit, second switch unit shutdown are stated, and based on the input terminal in second preset duration Second input current calculates the second pulsewidth;
When the conducting duration of the first switch unit reaches second preset duration, institute is controlled in second pulsewidth State the conducting of second switch unit, first switch unit shutdown;
When the conducting duration of the second switch unit reaches second pulsewidth, institute is controlled in the third preset duration The conducting of first switch unit, second switch unit shutdown are stated, and based on the input terminal in the third preset duration Third input current calculates third pulsewidth;
When the conducting duration of the first switch unit reaches the third preset duration, institute is controlled in the third pulsewidth State the conducting of second switch unit, first switch unit shutdown;
When the conducting duration of the second switch unit reaches the third pulsewidth, control first switch unit conducting, The second switch unit shutdown.
7. pulse width control method as claimed in claim 6, which is characterized in that described to be based on the input in the first preset duration End the first input current calculate the first pulsewidth the step of include:
Obtain the corresponding default maximum pulse width of first pulsewidth and corresponding first predetermined current, default minimum pulse width and correspondence The second predetermined current, and based on the default maximum pulse width, the first predetermined current, default minimum pulse width, the second predetermined current And first input current, calculate first pulsewidth according to linear interpolation algorithm.
8. pulse width control method as claimed in claim 6, which is characterized in that described in the conducting of the second switch unit When length reaches the third pulsewidth, after controlling the step of first switch unit is connected, the second switch unit turns off, Further include:
When detecting that the current input current of the input terminal reaches 0, the first switch unit shutdown is controlled.
9. pulse width control method as claimed in claim 6, which is characterized in that described based on pulse change number, burst length The input current of interval and the input terminal, control first switch unit, second switch units alternately ground ON/OFF, with And the step of pulsewidth when first switch unit conducting, includes:
The 4th input current based on the input terminal in the first preset duration calculates the 4th pulsewidth;
When the conducting duration of the 4th switch unit reaches first preset duration, institute is controlled in the 4th pulsewidth State the conducting of first switch unit;
When the conducting duration of the first switch unit reaches four pulsewidth, institute is controlled in second preset duration The conducting of second switch unit, first switch unit shutdown are stated, and based on the input terminal in second preset duration 5th input current calculates the 5th pulsewidth;
When the conducting duration of the second switch unit reaches five preset duration, institute is controlled in the 5th pulsewidth State the conducting of first switch unit, second switch unit shutdown;
When the conducting duration of the first switch unit reaches five pulsewidth, institute is controlled in the third preset duration The conducting of second switch unit, first switch unit shutdown are stated, and based on the input terminal in the third preset duration 6th input current calculates the 6th pulsewidth;
When the conducting duration of the second switch unit reaches the third preset duration, institute is controlled in the 6th pulsewidth State the conducting of first switch unit, second switch unit shutdown;
When the conducting duration of the first switch unit reaches six pulsewidth, control second switch unit conducting, The first switch unit shutdown.
10. pulse width control method as claimed in claim 9, which is characterized in that the conducting in the first switch unit When duration reaches six pulsewidth, the step of controlling second switch unit conducting, first switch unit shutdown it Afterwards, further include:
When detecting that the current input current of the input terminal reaches 0, the second switch unit shutdown is controlled.
11. the pulse width control method as described in any one of claim 5 to 10, which is characterized in that the pulse width control method Further include:
When the input current of the bridge circuit input terminal is more than predetermined current threshold, the first switch list is controlled respectively Member, second switch unit, third switch unit and the 4th switch unit shutdown.
12. a kind of air conditioner, which is characterized in that the air conditioner includes:Totem pfc circuit, storage described in claim 2 Device, processor and it is stored in the pulse-width controlled program that can be run on the memory and on the processor, the pulsewidth control The step of pulse width control method as described in any one of claim 5 to 11 is realized when processing procedure sequence is executed by the processor.
13. a kind of storage medium, which is characterized in that be stored with pulse-width controlled program, the pulse-width controlled on the storage medium The step of pulse width control method as described in any one of claim 5 to 11 is realized when program is executed by processor.
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