CN208369467U - totem PFC circuit and air conditioner - Google Patents
totem PFC circuit and air conditioner Download PDFInfo
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- CN208369467U CN208369467U CN201820850778.5U CN201820850778U CN208369467U CN 208369467 U CN208369467 U CN 208369467U CN 201820850778 U CN201820850778 U CN 201820850778U CN 208369467 U CN208369467 U CN 208369467U
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
- Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes
Abstract
The utility model discloses a kind of totem pfc circuit and air conditioners, wherein, totem pfc circuit includes: bridge circuit, reactor, bus capacitor and control module, control module is connected respectively at the input terminal of the bridge circuit and the load point, when being less than or equal to predetermined current threshold for the input current in the bridge circuit input terminal, according to the input voltage of the bridge circuit input terminal and the busbar voltage of the load, the switch state of each switch unit in the bridge circuit is controlled.The utility model realizes while reducing each switch unit on-off times, it is that each switch unit selects suitable pulsewidth according to input voltage and the busbar voltage of load, 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, and then reduce switching loss while idle work power in reducing circuit, improve the efficiency of totem pfc circuit.
Description
Technical field
The utility model relates to air-conditioning technical field more particularly to a kind of totem pfc circuits and air conditioner.
Background technique
With the development of power electronics technology, 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 type is generally used, this PFC simple structure, convenient control, but efficiency is more low
Under.Therefore, in some pairs of higher occasions 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 every half period 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, the less meeting of short circuit current flow number leads to totem pfc circuit so that the improvement of power factor is insufficient
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
The efficiency of column pfc circuit is lower.
Above content is only used for auxiliary and understands the technical solution of the utility model, does not represent and recognizes that above content is existing
Technology.
Utility model content
The main purpose of the utility model is to provide a kind of totem pfc circuit and air conditioners, it is intended to solve existing figure
Rise the lower technical problem of the efficiency of column pfc circuit.
To achieve the above object, the utility model provides a kind of totem pfc circuit, the totem PFC circuit packet
It includes:
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 bridge circuit
Input terminal is connected with AC power source, and output end is connected with load；
Reactor, the reactor are arranged between the bridge circuit and the AC power source；
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 connected respectively at the input terminal of the bridge circuit and the load point, are used for
When the input current of the bridge circuit input terminal is less than or equal to predetermined current threshold, according to the bridge circuit input terminal
Input voltage and the load busbar voltage, control the switch state of each switch unit in the bridge circuit.
In one embodiment, the bridge circuit include first switch unit, second switch unit, third switch unit and
4th switch unit；
The first switch unit and the second switch unit are connected in series to form the first branch, and the third switch is single
First to be connected in series to form second branch with the 4th switch unit, the first branch and second branch are connected in parallel to form institute
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 electrical connection；The third switch unit is electrically connected with the tie point of the 4th switch unit with the AC power source；
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, first switch unit, second switch unit, third switch unit and the 4th switch unit are
Metal-oxide-semiconductor.
In one embodiment, the control module includes: current detecting unit, the current detecting unit and the electric bridge
The input terminal of circuit is electrically connected, the input current of the input terminal for detecting the bridge circuit.
In one embodiment, the control module further include: busbar voltage detection unit, the busbar voltage detection unit
It is electrically connected with the input terminal of the load, for detecting the busbar voltage of the load.
In one embodiment, the control module further include: busbar voltage alternating voltage detection unit, the alternating voltage
Detection unit is electrically connected with the input terminal of the bridge circuit, the input voltage of the input terminal for detecting bridge circuit.
In one embodiment, the control module further include: control unit, described control unit are examined with the electric current respectively
Survey unit, busbar voltage detection unit and alternating voltage detection unit electrical connection；Described control unit is used in the electricity
When the input current that stream detection unit detects is less than or equal to predetermined current threshold, examined according to the busbar voltage detection unit
The input voltage that the busbar voltage and the alternating voltage detection unit measured detects, controls each in the bridge circuit
The switch state of switch unit.
In one embodiment, the control module further include: driving protection location and driving unit；
The driving protection location is electrically connected with current detecting unit and the driving unit respectively, in the electric current
When the input current that detection unit detects is greater than predetermined current threshold, shutdown control signal is sent to the 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.
In addition, to achieve the above object, the utility model also provides a kind of air conditioner, the air conditioner includes any of the above-described
Totem pfc circuit described in.
When the utility model 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 of bridge circuit input terminal and the busbar voltage of load, control the switch state of each switch unit with
And pulsewidth when each switching means conductive, it realizes while reducing each switch unit on-off times, according to input electricity
Pressure and the busbar voltage of load are that each switch unit selects suitable pulsewidth, can be in the electric current for meeting totem pfc circuit
Harmonic requirement, improve totem PFC circuit power factor under the premise of, reduce on-off times, to reduce short circuit current flow
Number, and then reduce switching loss while idle work power in reducing circuit, improve the efficiency of totem pfc circuit.
Detailed description of the invention
Fig. 1 is the electrical block diagram of one embodiment of the utility model totem pfc circuit；
Fig. 2 is the driving of AC supply voltage Vs, circuital current Is and switch unit Q1~Q4 in the utility model
The schematic diagram of the time change of pulse.
Drawing reference numeral explanation:
The embodiments will be further described with reference to the accompanying drawings for the realization, functional characteristics and advantage of the utility model aim.
Specific embodiment
The following will be combined with the drawings in the embodiments of the present invention, carries out the technical scheme in the embodiment of the utility model
Clearly and completely describing, it is clear that described embodiment is only a part of the embodiment of the utility model, rather than all
Embodiment.Based on the embodiments of the present invention, those of ordinary skill in the art are not making creative work premise
Under every other embodiment obtained, fall within the protection scope of the utility model.
It is to be appreciated that the directional instruction (such as up, down, left, right, before and after ...) of institute in the utility model embodiment
It is only used for explaining in relative positional relationship, the motion conditions etc. under a certain particular pose (as shown in the picture) between each component, such as
When the fruit particular pose changes, then directionality instruction also correspondingly changes correspondingly.
In addition, the description for being related to " first ", " second " etc. in the present invention is used for description purposes only, and cannot understand
For its relative importance of indication or suggestion or implicitly indicate the quantity of indicated technical characteristic.Define as a result, " first ",
The feature of " second " can explicitly or implicitly include at least one of the features.In addition, the technical side between each embodiment
Case can be combined with each other, but must be based on can be realized by those of ordinary skill in the art, when the combination of technical solution
Conflicting or cannot achieve when occur will be understood that the combination of this technical solution is not present, also not in the requires of the utility model
Protection scope within.
The utility model provides a kind of totem pfc circuit, and referring to Fig.1, Fig. 1 is the utility model totem pfc circuit
The electrical block diagram of first embodiment.
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 source.Reactor L savings is supplied from AC power source
The electric power given carries out realizing the boosting of totem pfc circuit and the improvement of power factor by discharging the energy as energy.
It is electrically connected after bus capacitor C is in parallel with load with the output end of bridge circuit 20.
Control module 10 is connected respectively at the input terminal of the bridge circuit and the load point.Control module 10 is used for
When the input current of 20 input terminal of bridge circuit is less than or equal to predetermined current threshold, the control module 10 is according to electric bridge
The input voltage of 20 input terminal of circuit and the busbar voltage of the load, control the switch state of each switch unit.
Control module 10 is also used to the control when the input current of 20 input terminal of bridge circuit is greater than predetermined current threshold
Each switch unit shutdown in bridge circuit 20 processed；And
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 greater 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, 10 bridge circuit 20 of control module is defeated
Enter the input voltage at end and the busbar voltage of the load, and according to the input voltage of 20 input terminal of bridge circuit and bus electricity
Pressure controls the pulsewidth when switch state and each switching means conductive of each switch unit, and then is reducing each switch
It is that each switch unit selects suitable pulsewidth, Neng Gou according to input voltage and busbar voltage while unit switch number
Under the premise of meeting the current harmonics requirement of totem pfc circuit, the power factor of improvement totem PFC circuit, switch is reduced
Number is improved efficiency with reducing switching loss.
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 second branch, and the first branch and second branch are connected in parallel to form the bridge circuit
20。
First switch unit Q1 is electrically connected via reactor L with AC power source 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 source.First switch unit Q1 and third switch
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
It can be that MOSFET (partly lead by Metal-Oxide-Semiconductor Field-Effect TransIstor, metal oxide
Body field effect transistor)/metal-oxide-semiconductor, such as super node MOSFET or SiC-MOSFET.Preferably, the source of first switch unit Q1
Pole is electrically connected with the drain electrode of second switch unit Q2, and tie point is electrically connected via reactor L with AC power source；Third switch is single
The source electrode of first Q3 is electrically connected with the drain electrode of the 4th switch unit Q4, and tie point is electrically connected with AC power source；First switch unit
The drain electrode of Q1 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 opens
The source electrode for closing unit Q2 is electrically connected with the source electrode of the 4th switch unit Q4, and 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) lower 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
Electric current is flowed through in the first switch unit Q1 of logical state and 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, busbar voltage detection unit 16.
The busbar voltage detection unit 16 is electrically connected with the input terminal of the load, for detecting the bus electricity of the load
Pressure.
The current detecting unit 12 is electrically connected with the input terminal of bridge circuit 20, for detecting the input of bridge circuit 20
The input current at end.
The alternating voltage detection unit 13 is electrically connected with the input terminal of bridge circuit 20, for detecting the defeated of bridge circuit 20
Enter the input voltage at end.
The control unit 11 is detected with current detecting unit 12, busbar voltage detection unit 16 and the alternating voltage respectively
Unit 13 is electrically connected.
The input current that the control unit 11 is used to detect in current detecting unit 12 is less than or equal to predetermined current threshold
When value, what the busbar voltage and the alternating voltage detection unit 13 detected according to busbar voltage detection unit 16 detected
Input voltage controls the arteries and veins when switch state and each switching means conductive of each switch unit in the bridge circuit 20
It is wide.
Preferably, in another embodiment, control module 10 further include: driving 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 greater 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 also used to detect in the current detecting unit 12 is less than or equal to default
When current threshold, the busbar voltage and alternating voltage detection unit 13 detected according to busbar voltage detection unit 16 is detected
Input voltage generate state control signal, and state control signal is sent to driving unit 15；The driving unit 15 is also used
In controlling in the bridge circuit 20 switch state of each switch unit and each according to the state control signal that receives
Pulsewidth when switching means conductive.
In other embodiments, which is also used to be in preset range in the busbar voltage of the load detected
When outer, shutdown control signal is sent to driving unit 15, which is used for according to the shutdown control signal control received
Each switch unit shutdown in bridge circuit 20 processed, to realize over-voltage/under-voltage protection of the middle load of totem pfc circuit.
Preferably, when controlling the switch state of each switch unit, it is single that control module 10 can also control each switch
Pulsewidth when member conducting.Its specific control process is as follows:
When the input current of 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 there is currently when positive and negative switching, positive and negative switching is determined
Whether the input voltage of input terminal is in positive half period afterwards；
When the input voltage of input terminal is in positive half period after positive and negative switching, the first switch unit Q1, are controlled
Two switch unit Q2 and third switch unit Q3 shutdown controls the 4th switch unit Q4 conducting；It is single in the 4th switch
When the conducting duration of member reaches first preset duration, the second switch unit conducting is controlled, and based on the load
First busbar voltage calculates the first pulsewidth；When the conducting duration of the second switch unit reaches first pulsewidth, control
The first switch unit conducting, second switch unit shutdown；Reach in the conducting duration of the 4th switch unit
When one duration, the second switch unit conducting, first switch unit shutdown are controlled, and second based on the load is female
Line voltage calculates the second pulsewidth, wherein the sum of a length of first preset duration and second preset duration when described first；
When the conducting duration of the second switch unit reaches second pulsewidth, controls the first switch unit and be connected, be described
The shutdown of second switch unit；When the conducting duration of the 4th switch unit reaches the second duration, the second switch is controlled
Unit conducting, first switch unit shutdown, and the third busbar voltage based on the load calculates third pulsewidth, wherein
The sum of a length of third preset duration and second duration when described second；Step S360, in the second switch unit
Conducting duration when reaching the third pulsewidth, control the first switch unit conducting, second switch unit shutdown；?
When detecting that the current input current of bridge circuit input terminal reaches 0, the first switch unit Q1 shutdown is controlled；
When the input voltage of input terminal is in negative half-cycle after positive and negative switching, the first switch unit Q1, are controlled
Two switch unit Q2 and the 4th switch unit Q4 shutdown, and the third switch unit Q3 conducting is controlled, in the 4th switch
When the conducting duration of unit reaches first preset duration, the first switch unit conducting is controlled, and be based on the load
The 4th busbar voltage calculate the 4th pulsewidth；When the conducting duration of the first switch unit reaches four pulsewidth, control
Make the second switch unit conducting, first switch unit shutdown；Reach in the conducting duration of the 4th switch unit
When the first duration, the first switch unit conducting, second switch unit shutdown, and the based on the load the 5th are controlled
Busbar voltage calculates the 5th pulsewidth；When the conducting duration of the first switch unit reaches five pulsewidth, described in control
The conducting of second switch unit, first switch unit shutdown；When the conducting duration of the 4th switch unit reaches second
When long, the first switch unit conducting, second switch unit shutdown, and the electricity of the 6th bus based on the load are controlled
Pressure calculates the 6th pulsewidth；When the conducting duration of the first switch unit Q1 reaches six pulsewidth, control described second
Switch unit Q2 conducting, first switch unit Q1 shutdown；Detecting that the current input current of bridge circuit input terminal reaches
When to 0, the second switch unit Q2 shutdown is controlled.
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 greater 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, that is, judge whether AC supply voltage Vs carries out
Positive and negative switching (whether having reached zero passage).Wherein, defeated after positive and negative switching there is currently determining when positive and negative switching in input voltage
Whether the input voltage for entering end is in positive half period, that is, determines whether the input voltage of currently detected input terminal is greater than 0 V,
When input voltage is greater than 0V, the input voltage of input terminal is in positive half period after positive and negative switching, otherwise, inputs after positive and negative switching
The input voltage at end is in negative half-cycle.
Wherein, the first preset duration, the second preset duration and third preset duration can be according to the totem pfc circuits
Demand is reasonably arranged.Wherein it is possible to which the busbar voltage instantaneous value that loads is as the when second switch unit Q2 is connected
One busbar voltage, the busbar voltage instantaneous value loaded when alternatively, the conducting duration of second switch unit Q2 being reached preset duration
As the first busbar voltage.Specifically, the voltage difference of first busbar voltage and default busbar voltage is calculated, and is based on institute
It states voltage difference and obtains first pulsewidth.In the present embodiment, when determining the first busbar voltage, first bus electricity is calculated
The voltage difference of pressure and default busbar voltage, and voltage difference specifically can be stored in advance based on the first pulsewidth of voltage difference acquisition
The mapping relations of the difference range of value and the mapping relations of pulsewidth or voltage difference and pulsewidth, when voltage difference is calculated,
According to corresponding first pulsewidth of the mapping relationship searching voltage difference, and then the first arteries and veins of second switch unit Q2 is rationally set
Width, to reasonably adjust the duration of totem pfc circuit short circuit currents, which can rationally be set
It sets, alternatively, the busbar voltage is the demand voltage for the busbar voltage that the first busbar voltage corresponds to the moment.
The acquisition mode of the second/tri-/tetra-/five/six busbar voltages is similar with the first busbar voltage, the second/tri-/tetra-/five/
The calculation of six pulsewidths is similar with the calculation of the first pulsewidth, and details are not described herein.
Wherein, the first pulsewidth is less than the second preset duration, and the second pulsewidth is less than third preset duration, and the 4th pulsewidth is less than the
Two preset durations, the 5th pulsewidth are less than third preset duration, also settable 4th preset duration, and third pulsewidth is preset less than the 4th
Duration, the 6th pulsewidth is less than the 4th preset duration.
Specifically, Fig. 2 is the drive of AC supply voltage Vs, circuital current Is and switch unit Q1~Q4 referring to Fig. 2
The schematic diagram of the time change of moving pulse, in Fig. 2, T1, T2, T3, T4 are respectively the first preset duration, the second preset duration,
Three preset durations and the 4th preset duration, D1, D2, D3 are respectively the first pulsewidth, the second pulsewidth, third pulsewidth, in alternating voltage
Positive half period, the 4th switch unit Q4 conducting, third switch unit Q3 shutdown；After voltage zero-cross delay time T1, second
Switch unit Q2 conducting；After second switch unit Q2 turn-on time D1, second switch unit Q2 shutdown, first switch unit Q1 is led
It is logical；After first switch unit Q1 turn-on time T2-D1, first switch unit Q1 shutdown, second switch unit Q2 conducting；Second
After switch unit Q2 turn-on time D2, second switch unit Q2 shutdown, first switch unit Q1 conducting；First switch unit Q1 is led
After logical time T3-D2, first switch unit Q1 shutdown, second switch unit Q2 is connected, after turn-on time D3, second switch list
First Q2 shutdown, first switch unit Q1 conducting.In this way, Q1 and Q2 alternate conduction/shutdown 3 times, wherein in second switch unit
When Q2 is connected, the input current Is (circuital current) of totem pfc circuit rises, in first switch unit Q1 conducting, input
Electric current decline；First switch unit Q1 is turned off before the positive half period of alternating voltage terminates, and can prevent from flowing from bus capacitor C
Cross adverse current electric current.
Referring to Fig. 2, in the negative half-cycle of alternating voltage, the 4th switch unit Q4 shutdown, third switch unit Q3 are connected,
D1, D2, D3 are respectively the 4th pulsewidth, the 5th pulsewidth, the 6th pulsewidth；After voltage zero-cross delay time T1, first switch unit
Q1 conducting；After first switch unit Q1 turn-on time D1, second switch unit Q2 conducting, first switch unit Q1 shutdown；Second
After switch unit Q2 turn-on time T2-D1, second switch unit Q2 shutdown, first switch unit Q1 conducting；First switch unit
After Q1 turn-on time D2, first switch unit Q1 shutdown, second switch unit Q2 conducting；Second switch unit Q2 turn-on time
After T3-D2, second switch unit Q2 shutdown, first switch unit Q1 is connected, after turn-on time D3, first switch unit Q1, the
Two switch unit Q2 conducting.In this way, Q1 and Q2 alternate conduction/shutdown 3 times, wherein in second switch unit Q2 conducting, figure
The input current Is (circuital current) for rising column PFC circuit rises, in first switch unit Q1 conducting, input current decline；?
The negative half-cycle of alternating voltage turns off second switch unit Q2 before terminating, and can prevent from flowing through adverse current electric current from bus capacitor C.
Above-mentioned first switch unit Q1/ second switch unit Q2 pulse change number is 3 times, in other embodiments, can
The pulse change number is rationally set, and similar when control process with pulse change number is 3 times, details are not described herein.
When the input voltage of input terminal is in positive half period after positive and negative switching, third switch unit Q3 shutdown, the 4th are opened
Unit Q4 is closed, if second switch unit Q2 conducting, first switch unit Q1 shutdown, totem pfc circuit carries out improvement function at this time
The operation of rate factor flows through the circuital current Is (input current of bridge circuit input terminal) of totem pfc circuit as short circuit electricity
Stream, and short circuit current sequence flows through AC power source-the 4th switch unit Q4- alternating current of reactor L- second switch unit Q2-
Source, reactor L puts aside energy by short circuit current at this time.Correspondingly, the input voltage of input terminal is in negative after positive and negative switching
When the half period, third switch unit Q3 conducting, the 4th switch unit Q4 shutdown, if second switch unit Q2 shutdown, first switch
Unit Q1 conducting, totem pfc circuit improve the operation of power factor at this time, flows through the circuit electricity of totem pfc circuit
Flowing Is (input current of bridge circuit input terminal) is short circuit current, and short circuit current sequence flows through AC power source-third and opens
Unit Q3- first switch unit Q1- reactor L- AC power source is 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 shutdown, the 4th are opened
Unit Q4 conducting is closed, if second switch unit Q2 shutdown, first switch unit Q1 conducting, according to exchange in totem pfc circuit
Power supply-the 4th switch unit Q4- AC power source of reactor L- first switch unit Q1- bus capacitor C- sampling resistor R- is suitable
Sequence flows through circuital current Is (input current of bridge circuit input terminal), and the energy put aside in reactor L is discharged to bus capacitor C
Amount, boosts to the DC voltage of bus capacitor C.Correspondingly, the input voltage of input terminal is in negative half after positive and negative switching
When the period, third switch unit Q3 conducting, the 4th switch unit Q4 shutdown, if second switch unit Q2 conducting, first switch list
First Q1 is turned off, according to AC power source-third switch unit Q3- bus capacitor C- sampling resistor R- second in totem pfc circuit
The sequential flow oversampling circuit electric current Is (input current of bridge circuit input terminal) of switch unit Q2- reactor L- AC power source, to
Bus capacitor C discharges the energy put aside in reactor L, boosts 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 is able to suppress the higher hamonic wave associated with higher harmonic current.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 reasonably 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, reduces switching loss, improves efficiency.
For example, with the rising of revolving speed, the induced voltage of compressor is got higher when load is the compressor of air conditioner, pressure
Contracting machine becomes difficult to drive, but by being alternately carried out above-mentioned " power-factor improvement movement " and " synchronous rectification movement "
It boosts, can be improved the permission limit of motor speed.
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 is according to the input voltage of 20 input terminal of bridge circuit and the busbar voltage of load, control
The pulsewidth when switch state and each switching means conductive of each switch unit is made, realizes and is reducing each switch unit
It is that each switch unit selects suitable pulsewidth according to input voltage and the busbar voltage of load while on-off times, it can
Under the premise of meeting the current harmonics requirement of totem pfc circuit, improving the power factor of totem pfc circuit, reduction is opened
Number is closed, to reduce the number of short circuit current flow, and then reduces switching loss while idle work power in reducing circuit,
Improve the efficiency of totem pfc circuit.
The utility model also proposes a kind of air conditioner, which includes totem pfc circuit, the totem pfc circuit
Specific structure referring to above-described embodiment, since this air conditioner uses whole technical solutions of above-mentioned all embodiments,
All beneficial effects brought by the same technical solution with above-described embodiment, this is no longer going to repeat them.
The above is only the preferred embodiments of the utility model, and therefore it does not limit the scope of the patent of the utility model, all
Equivalent structure or equivalent flow shift made based on the specification and figures of the utility model, is applied directly or indirectly in
Other related technical areas are also included in the patent protection scope of the utility model.
Claims (9)
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 source, and output end is connected with load；
Reactor, the reactor are arranged between the bridge circuit and the AC power source；
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 connected respectively at the input terminal of the bridge circuit and the load point, in institute
When stating the input current of bridge circuit input terminal less than or equal to predetermined current threshold, according to the defeated of the bridge circuit input terminal
The busbar voltage for entering voltage and the load controls the switch state of each switch unit in the bridge circuit.
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 second branch, and the first branch and second branch are connected in parallel to form the electricity
Bridge circuit；
The tie point of the first switch unit and the second switch unit is via the reactor and AC power source electricity
Connection；The third switch unit is electrically connected with the tie point of the 4th switch unit with the AC power source；
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 claimed in claim 2, which is characterized in that first switch unit, second switch unit,
Three switch units and the 4th switch unit are metal-oxide-semiconductor.
4. totem pfc circuit as described in claim 1, which is characterized in that the control module includes: current detecting list
Member, the current detecting unit are electrically connected with the input terminal of the bridge circuit, for detecting the input terminal of the bridge circuit
Input current.
5. totem pfc circuit as claimed in claim 4, which is characterized in that the control module further include: busbar voltage inspection
Unit is surveyed, the busbar voltage detection unit is electrically connected with the input terminal of the load, for detecting the bus electricity of the load
Pressure.
6. totem pfc circuit as claimed in claim 5, which is characterized in that the control module further include: busbar voltage is handed over
Voltage detection unit is flowed, the alternating voltage detection unit is electrically connected with the input terminal of the bridge circuit, for detecting electric bridge
The input voltage of the input terminal of circuit.
7. totem pfc circuit as claimed in claim 6, which is characterized in that the control module further include: control unit,
Described control unit is electrically connected with the current detecting unit, busbar voltage detection unit and the alternating voltage detection unit respectively
It connects；The input current that described control unit is used to detect in the current detecting unit is less than or equal to predetermined current threshold
When, the busbar voltage and the alternating voltage detection unit detected according to the busbar voltage detection unit detects defeated
Enter voltage, controls the switch state of each switch unit in the bridge circuit.
8. the totem pfc circuit as described in any one of claims 1 to 7, which is characterized in that the control module is also wrapped
It includes: driving protection location and driving unit；
The driving protection location is electrically connected with current detecting unit and the driving unit respectively, in the current detecting
When the input current that unit detects is greater than predetermined current threshold, shutdown control signal is sent to the driving unit；
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.
9. a kind of air conditioner, which is characterized in that the air conditioner includes totem PFC described in any item of the claim 1 to 8
Circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201820850778.5U CN208369467U (en) | 2018-06-01 | 2018-06-01 | totem PFC circuit and air conditioner |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201820850778.5U CN208369467U (en) | 2018-06-01 | 2018-06-01 | totem PFC circuit and air conditioner |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN208369467U true CN208369467U (en) | 2019-01-11 |
Family
ID=64931393
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201820850778.5U Active CN208369467U (en) | 2018-06-01 | 2018-06-01 | totem PFC circuit and air conditioner |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN208369467U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113972821A (en) * | 2020-07-22 | 2022-01-25 | 广东美的制冷设备有限公司 | Totem-pole power factor correction circuit, control method, circuit board and air conditioner |
| WO2022017330A1 (en) * | 2020-07-22 | 2022-01-27 | 广东美的制冷设备有限公司 | Totem-pole pfc circuit and control method therefor, circuit board, air conditioner, and storage medium |
-
2018
- 2018-06-01 CN CN201820850778.5U patent/CN208369467U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113972821A (en) * | 2020-07-22 | 2022-01-25 | 广东美的制冷设备有限公司 | Totem-pole power factor correction circuit, control method, circuit board and air conditioner |
| WO2022017330A1 (en) * | 2020-07-22 | 2022-01-27 | 广东美的制冷设备有限公司 | Totem-pole pfc circuit and control method therefor, circuit board, air conditioner, and storage medium |
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