CN106026720B - A kind of PFC sample circuit and air conditioner - Google Patents
A kind of PFC sample circuit and air conditioner Download PDFInfo
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- CN106026720B CN106026720B CN201610494246.8A CN201610494246A CN106026720B CN 106026720 B CN106026720 B CN 106026720B CN 201610494246 A CN201610494246 A CN 201610494246A CN 106026720 B CN106026720 B CN 106026720B
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
- H02M7/02—Conversion of ac power input into dc power output without possibility of reversal
- H02M7/04—Conversion of ac power input into dc power output without possibility of reversal by static converters
- H02M7/12—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M7/21—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M7/217—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M7/219—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only in a bridge configuration
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/42—Circuits or arrangements for compensating for or adjusting power factor in converters or inverters
- H02M1/4208—Arrangements for improving power factor of AC input
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/0003—Details of control, feedback or regulation circuits
- H02M1/0009—Devices or circuits for detecting current in a converter
-
- 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 present invention provides a kind of PFC sample circuit and air conditioners, comprising: the first accumulator, semi-bridge switching circuit, rectification circuit, the second accumulator, controller and current sampling circuit；The current sampling circuit is connect with the input terminal of the controller；The current sampling circuit includes sampling resistor, is connected between AC power source and the first accumulator, alternatively, being connected between the first accumulator and the semi-bridge switching circuit, alternatively, being connected between AC power source and rectification circuit；Two switching tubes of the semi-bridge switching circuit work in complementary fashion in every half of ac period, every half of ac period controls two switching tube timesharing conductings, it realizes the charge and discharge of the first accumulator and the second accumulator, and passes through the current value in sampling resistor acquisition circuit simultaneously.Current sample is not necessarily to current sensor in the present invention, and component number is few, and circuit structure is simple, the device volume of installing the circuit is small, at low cost and be easily achieved.
Description
Technical field
The present invention relates to current sampling technique field more particularly to a kind of PFC sample circuits and air conditioner.
Background technique
Totem pole configuration without bridge power factor correction circuit (abbreviation PFC) because have power device is few, electricity is effectively reduced
The advantages such as road harmonic wave, working efficiency height have a good application prospect.Its working principle is that passing through control upper and lower bridge arm power device
The conducting dutycycle adjustment input current waveform of part is realized.And working efficiency and PFC effect are directly by sample circuit
Sampling precision influence.
Currently, generalling use the electric current in current sensor acquisition pfc circuit.Inductive current is sampled using current sensor
Sample circuit structure as shown in Figure 1, it is simple with structure, stability is good, controller and power drive altogether, current sample
The anti-interference advantages such as strong.When the circuit works, the electric current on the inductance L1 as energy storage device, real-time control can be effectively detected
Input current follows input voltage waveform, and directly, but that there are Current Transmit volumes is big, price is high for control, can not protect Q1,
The disadvantages of Q2 power tube short circuit, therefore, it is difficult to widespread adoptions in product.Using current sensor sampled power device current electricity
Line structure as shown in Fig. 2, it is good with stability, controller with power drive altogether, electromagnetic compatibility (EMI) effect it is good, be easy
The advantages that realizing the protection of Q1, Q2 power tube current.But due to needing two current sensors CT1, CT2 as Sampling device, at
This height and occupancy fabric swatch space, therefore application implementation is more difficult.
Summary of the invention
In view of the drawbacks of the prior art, the present invention provides a kind of PFC sample circuit and air conditioner, it is able to solve existing skill
It is big, at high cost using current sensor acquisition electric current volume and occupy fabric swatch space in art, therefore application implementation is more difficult asks
Topic.
In a first aspect, the present invention provides a kind of PFC sample circuits, comprising: the first accumulator, semi-bridge switching circuit,
Rectification circuit, the second accumulator and controller；One end of AC power source connects one end of first accumulator, the first storage
The other end of energy circuit connects semi-bridge switching circuit, and semi-bridge switching circuit, rectification circuit, the second accumulator and load are simultaneously
Connection；The other end of AC power source connects rectification circuit, and controller connects semi-bridge switching circuit；Further include: current sampling circuit；Institute
Current sampling circuit is stated to connect with the input terminal of the controller；
The current sampling circuit includes sampling resistor, be connected to the AC power source and first accumulator it
Between, alternatively, being connected between first accumulator and the semi-bridge switching circuit, alternatively, being connected to the AC power source
Between the rectification circuit；
Two switching tubes of the semi-bridge switching circuit work in complementary fashion in every half of ac period, every half of friendship
The galvanic electricity period controls two switching tube timesharing conductings, realizes the charge and discharge of the first accumulator and the second accumulator, and simultaneously
The current value in circuit is obtained by the sampling resistor.
Preferably, the semi-bridge switching circuit includes concatenated first switch tube and second switch, first energy storage
The common end of first switch tube described in circuit connection and the second switch, the output end connection described first of the controller
The control terminal of switching tube and the second switch；
The current sampling circuit includes first resistor, and one end of one end of the AC power source and the first resistor connects
It connects, the other end of the first resistor is connect with first accumulator；The first resistor passes through operational amplifier and institute
State the input terminal connection of controller；
In every half of ac period, when first switch tube disconnects and second switch is connected, the electric current stream of AC power source
It is flow back into AC power source through first resistor, the first accumulator, second switch and rectification circuit, passes through the first resistor institute
It states controller and obtains the first sample rate current；When first switch tube conducting and second switch disconnection, the electric current of AC power source is flowed through
First resistor, the first accumulator, first switch tube, the second accumulator and rectification circuit flow back into AC power source, pass through institute
It states controller described in first resistor and obtains the second sample rate current；The controller is sampled according to first sample rate current and second
Electric current obtains PFC average current.
Preferably, the PFC sample circuit further include: short-circuit protection circuit；
One end of the short-circuit protection circuit is connect with the semi-bridge switching circuit, the other end of the short-circuit protection circuit
It is connect with second accumulator, and the short-circuit protection circuit is connect with the input terminal of the controller.
Preferably, the short-circuit protection circuit includes: second resistance；
One end of the second resistance is connect with the semi-bridge switching circuit, the other end of the second resistance with it is described whole
Current circuit and second accumulator connection；The input that the second resistance passes through isolation operational amplifier and the controller
End connection；
When the first switch tube conducting and second switch conducting, second accumulator passes through described first
The shunt circuit of switching tube, the second switch and the second resistance and the load is discharged, and the second resistance is passed through
The controller obtains power device branch current, and is used for discharge prevention.
Preferably, the PFC sample circuit further include: AC-input voltage sample circuit and DC bus-bar voltage sampling electricity
Road；The AC-input voltage sample circuit and the DC-bus voltage sampling circuit connect with the input terminal of the controller
It connects；
The AC-input voltage sample circuit, is connected to the both ends of the AC power source, for acquiring exchange input electricity
Pressure, and it is sent to the controller；
The DC-bus voltage sampling circuit is connected to second accumulator both ends, for acquiring DC bus
Voltage, and it is sent to the controller.
Preferably, the AC-input voltage sample circuit includes: 3rd resistor, the 4th resistance and the first differential amplification
Device；
One end of the 3rd resistor is connect with the AC power source and the rectification circuit, the 3rd resistor it is another
End is connect with the first input end of first difference amplifier；One end of 4th resistance and the AC power source and described
Sampling resistor connection, the other end of the 4th resistance are connect with the second input terminal of first difference amplifier；Described
The output end of one difference amplifier is connect with the input terminal of the controller.
Preferably, the DC-bus voltage sampling circuit includes: the 5th resistance, the 6th resistance, the 7th resistance, the 8th electricity
Resistance, the 9th resistance, the tenth resistance and the second difference amplifier；
One end of 5th resistance is connect with one end of second accumulator, the other end of the 5th resistance with
One end of 6th resistance connects, the other end of the 6th resistance and one end of the 7th resistance and second difference
The first input end of amplifier connects, and the other end of the 7th resistance is connected to ground；One end of 8th resistance with it is described
The other end of second accumulator connects, and the other end of the 8th resistance is connect with one end of the 9th resistance, and described the
The other end of nine resistance is connect with second input terminal of one end of the tenth resistance and second difference amplifier, and described
The other end of ten resistance is connected to ground；The output end of second difference amplifier is connect with the input terminal of the controller.
Preferably, the PFC sample circuit further include: filter circuit；
One end of the filter circuit is connect with one end of the AC power source, the other end of the filter circuit with it is described
The other end of AC power source connects.
Preferably, first accumulator uses inductance L；Second accumulator uses capacitor C.
Second aspect, the present invention provides a kind of air conditioners, including any one of the above PFC sample circuit, the PFC to adopt
The load end of sample circuit connects inverter circuit, and the inverter circuit connects compressor of air conditioner, and controller includes PFC control terminal and inverse
Power transformation road control terminal, the PFC control terminal connect semi-bridge switching circuit, and the inverter circuit control terminal connects inverter circuit.
As shown from the above technical solution, use sampling resistor as current sampler in the PFC sample circuit in the present invention
Part, and two switching tubes for controlling the semi-bridge switching circuit work in complementary fashion in every half of ac period, every half
Ac period controls two switching tube timesharing conductings, realizes the charge and discharge of the first accumulator and the second accumulator, and same
When pass through the sampling resistor obtain circuit in current value.It can be seen that current sample is not necessarily to current sensor in the present invention,
Component number is few, and circuit structure is simple, the device volume of installing the circuit is small, at low cost and be easily achieved.
Detailed description of the invention
In order to more clearly explain the embodiment of the invention or the technical proposal in the existing technology, to embodiment or will show below
There is attached drawing needed in technical description to be briefly described, it should be apparent that, the accompanying drawings in the following description is only this
Some embodiments of invention for those of ordinary skill in the art without creative efforts, can be with
Other attached drawings are obtained according to these figures.
Fig. 1 is in the prior art using the circuit diagram of current sensor sampling inductive current；
Fig. 2 is the circuit diagram for using current sensor sampled power device current in the prior art；
Fig. 3 is the schematic diagram of the PFC sample circuit in the embodiment of the present invention 1；
Fig. 4 is the schematic diagram of the PFC sample circuit in the embodiment of the present invention 2；
Fig. 5 is the schematic diagram of the PFC sample circuit in the embodiment of the present invention 3；
Current flowing situation schematic diagram when Fig. 6 a~6c is power input voltage positive half period in the embodiment of the present invention；
Current flowing situation schematic diagram when Fig. 7 a~7c is power input voltage positive half period in the embodiment of the present invention；
Fig. 8 be another embodiment of the present invention provides a kind of air conditioner schematic diagram；
Description of symbols in Fig. 2~Fig. 5: the first accumulator of 1-；2- semi-bridge switching circuit；3- rectification circuit；4-
Second accumulator；5- controller；6- current sampling circuit；7- short-circuit protection circuit；8- filter circuit.
Specific embodiment
Following will be combined with the drawings in the embodiments of the present invention, and technical solution in the embodiment of the present invention carries out clear, complete
Site preparation description, it is clear that described embodiments are only a part of the embodiments of the present invention, instead of all the embodiments.It is based on
Embodiment in the present invention, it is obtained by those of ordinary skill in the art without making creative efforts every other
Embodiment shall fall within the protection scope of the present invention.
Embodiment 1
The embodiment of the present invention 1 provides a kind of PFC sample circuit, the PFC sample circuit include: the first accumulator,
Semi-bridge switching circuit, rectification circuit, the second accumulator and controller.Wherein, one end connection of AC power source first storage
The other end of one end of energy circuit, the first accumulator connects semi-bridge switching circuit, semi-bridge switching circuit, rectification circuit, second
Accumulator and load are in parallel；The other end of AC power source connects rectification circuit, and controller connects semi-bridge switching circuit.
The PFC sample circuit further include: current sampling circuit；The input terminal of the current sampling circuit and the controller
Connection.The current sampling circuit includes sampling resistor, is connected between the AC power source and first accumulator, or
Person is connected between first accumulator and the semi-bridge switching circuit, alternatively, be connected to the AC power source with it is described
Between rectification circuit.Two switching tubes of the semi-bridge switching circuit work in complementary fashion in every half of ac period, often
Half of ac period controls two switching tube timesharing conductings, realizes the charge and discharge of the first accumulator and the second accumulator,
And pass through the current value in sampling resistor acquisition circuit simultaneously.
By taking current sampling circuit is connected between the AC power source and first accumulator as an example, as shown in figure 3,
PFC sample circuit include: the first accumulator 1, semi-bridge switching circuit 2, rectification circuit 3, the second accumulator 4, controller 5 and
Current sampling circuit 6.Wherein, AC power source AC one end connection current sampling circuit 6 one end, current sampling circuit 6 it is another
One end connects one end of first accumulator 1, and the other end of the first accumulator 1 connects semi-bridge switching circuit 2, and half-bridge is cut
It is in parallel to change circuit 2, rectification circuit 3, the second accumulator 4 and load；The other end of AC power source AC connects rectification circuit 3,
Controller 5 connects semi-bridge switching circuit 2.Wherein, current sampling circuit 6 includes noninductive resistance R1.
It should be noted that controller 5 is connected to the ground of current sampling circuit 6, and controller 5 and semi-bridge switching circuit 2
In two switching tubes be isolated, therefore two switching tubes in controller 5 and semi-bridge switching circuit 2 pass through isolation drive respectively
Device T1, T2 connection.
It can be seen that using sampling resistor as current sampling devices in PFC sample circuit in the present embodiment, and control
Two switching tubes of the semi-bridge switching circuit work in complementary fashion in every half of ac period, every half of ac period
Two switching tube timesharing conductings are controlled, realize the charge and discharge of the first accumulator and the second accumulator, and simultaneously by described
Sampling resistor obtains the current value in circuit.It can be seen that being not necessarily to current sensor in the present embodiment, component number is few, electricity
The device volume that line structure is simple, installs the circuit is small, at low cost and be easily achieved.
Specifically, the semi-bridge switching circuit 2 includes concatenated first switch tube Q1 and second switch Q2, and described the
One accumulator 1 connects the common end of the first switch tube Q1 and the second switch Q2, the output end of the controller 5
Connect the control terminal of the first switch tube Q1 and the second switch Q2.The current sampling circuit 6 includes first resistor
R1, one end of the AC power source AC are connect with one end of the first resistor R1, the other end of the first resistor R1 and institute
State the connection of the first accumulator 1；The first resistor R1 is connect by operational amplifier OP1 with the input terminal of the controller 5.
Two switching tubes Q1, Q2 work in complementary fashion in every half of ac period, every half of ac period control
Two switching tube Q1, Q2 timesharing conductings.Specifically, in every half of ac period, first switch tube Q1 is disconnected and second switch
When pipe Q2 is connected, the electric current of AC power source AC flows through first resistor R1, the first accumulator 1, second switch Q2 and rectified current
Road 3 flow back into AC power source AC, obtains the first sample rate current by controller described in the first resistor R1；First switch tube is led
Logical Q1 and when second switch Q2 is disconnected, the electric current of AC power source AC flow through first resistor R1, the first accumulator 1, first open
It closes pipe Q1, the second accumulator 4 and rectification circuit 3 and flow back into AC power source AC, pass through controller described in the first resistor R1
Obtain the second sample rate current；The controller 5 obtains the average electricity of PFC according to first sample rate current and the second sample rate current
Stream.
Specifically, first accumulator 1 uses inductance L1, and second accumulator 4 uses capacitor C1.It is described
Semi-bridge switching circuit 2 includes concatenated first switch tube Q1 and second switch Q2, the first switch tube Q1 and second switch
Pipe Q2 is not simultaneously turned on according to the control signal of controller 5, is worked in complementary fashion.The rectification circuit 3 includes concatenated the
One diode D1 and the second diode D2, the first diode D1 and the of the other end connection rectification circuit 3 of the AC power source
The common end of two diode D2.The anode of first diode D1 and the cathode of the second diode D2 are connected to the another of AC power source
One end, the anode connection second switch Q2 of the second diode D2.The first switch tube Q1 and second switch Q2 can
Using metal-oxide-semiconductor or IGBT.
Embodiment 2
As shown in figure 4, on the basis of embodiment 1, the PFC sample circuit further include: short-circuit protection circuit 7.
One end of the short-circuit protection circuit 7 is connect with the semi-bridge switching circuit 2, the short-circuit protection circuit 7 it is another
One end is connect with second accumulator 3, and the short-circuit protection circuit 3 is connect with the input terminal of the controller 5.
Specifically, the short-circuit protection circuit includes: second resistance R2.One end of the second resistance R2 and described half
Bridge switching circuit 2 connects, and the other end of the second resistance R2 is connect with the rectification circuit 3 and second accumulator 4；
The second resistance R2 is connect by the way that operational amplifier OP2 is isolated with the input terminal of the controller 5.It will be appreciated that due to
Second resistance R2 is isolated with the ground of controller 5, therefore R2 need to be isolated with controller 5 using isolation operational amplifier.
Correspondingly, first switch tube Q1 conducting and when the second switch Q2 is connected, second accumulator 4
It is put by the first switch tube Q1, the second switch Q2 and the second resistance R2 and the shunt circuit of the load
Electricity obtains power device branch current by controller 5 described in the second resistance R2, and is used for discharge prevention.Then when first
When switching tube Q1 and second switch Q2 are simultaneously turned on, R2 cannot be only used for the current value of acquisition power device branch road, moreover it is possible to
Discharge prevention is carried out to the circuit of the second accumulator 4, first switch tube Q1, second switch Q2 and second resistance R2 composition,
Prevent capacitor C1 discharge short.
Embodiment 3
In the present embodiment, based on the PFC sample circuit in embodiment 1 and embodiment 2, the PFC in the present embodiment samples electricity
Road further include: AC-input voltage sample circuit and DC-bus voltage sampling circuit；The AC-input voltage sample circuit
And the DC-bus voltage sampling circuit is connect with the input terminal of the controller；The AC-input voltage sampling electricity
Road is connected to the both ends of the AC power source, for acquiring AC-input voltage, and is sent to the controller；The direct current
Busbar voltage sample circuit is connected to second accumulator both ends, for acquiring DC bus-bar voltage, and is sent to described
Controller.
Specifically, as shown in figure 5, the AC-input voltage sample circuit includes: 3rd resistor R3, the 4th resistance R4
And the first difference amplifier U1.Wherein, one end of the 3rd resistor R3 and the AC power source AC and the rectification circuit 3 connect
It connects, the other end of the 3rd resistor R3 is connect with the first input end of the first difference amplifier U1；4th resistance
One end of R4 is connect with the AC power source and the sampling resistor R1, the other end of the 4th resistance R4 with it is described first poor
Divide the second input terminal connection of amplifier U1；The output end of the first difference amplifier U1 and the input terminal of the controller 5
Connection.
The DC-bus voltage sampling circuit includes: the 5th resistance R5, the 6th resistance R6, the 7th resistance R7, the 8th electricity
Hinder R8, the 9th resistance R9, the tenth resistance R10 and the second difference amplifier U2.Wherein, one end of the 5th resistance R5 with it is described
One end of second accumulator 4 connects, and the other end of the 5th resistance R5 is connect with one end of the 6th resistance R6, described
The first input end of one end and the second difference amplifier U2 of the other end of the 6th resistance R6 and the 7th resistance R7 connects
It connects, the other end of the 7th resistance R7 is connected to ground；One end of the 8th resistance R8 is another with second accumulator 4
One end connection, the other end of the 8th resistance R8 are connect with one end of the 9th resistance R9, and the 9th resistance R9's is another
One end is connect with second input terminal of one end of the tenth resistance R10 and the second difference amplifier U2, the tenth electricity
The other end of resistance R10 is connected to ground；The output end of the second difference amplifier U2 is connect with the input terminal of the controller 5.
Further, as shown in figure 5, the PFC sample circuit further include: filter circuit 8.Wherein, the filter circuit 8
One end connect with one end of the AC power source AC, the other end of the filter circuit 8 is another with the AC power source AC's
End connection.
It should be noted that the load end in above-described embodiment connects inverter circuit, the inverter circuit connects motor.
It as shown in Figure 6 a, is power input voltage positive half period, controller 5 controls first switch tube Q1 shutdown and second opens
Current flow diagram when closing pipe Q2 conducting.The electric current of AC power source AC flows through first resistor R1, inductance L1, second switch
Q2, second resistance R2 and the second diode D2 flow back into AC power source AC, realize the thermal energy storage process to inductance L1, while capacitor
C1 provides energy to load discharge.First resistor R1 samples to obtain PFC inductive current IL1 at this time.
It as shown in Figure 6 b, is power input voltage positive half period, controller 5 controls first switch tube Q1 conducting and second opens
Current flow diagram when closing pipe Q2 shutdown.The electric current of AC power source AC flows through first resistor R1, inductance L1, first switch tube
Q1, capacitor C1 and the second diode D2 flow back into AC power source AC, discharge the energy of the storage of inductance L1, while to capacitor
C1 charges.First resistor R1 samples to obtain PFC inductive current IL2 at this time.Controller 5 according to PFC inductive current IL1 and
PFC inductive current IL2 operation obtains PFC average current.
It as fig. 6 c, is power input voltage positive half period, first switch tube Q1 conducting and second switch Q2 conducting
When current flow diagram.Capacitor C1 simultaneously returns first switch tube Q1, second switch Q2 and second resistance R2 composition
Road, and the circuit electric discharge that load is constituted.Pass through second resistance R2 sampled power device branch current at this time；Simultaneously because capacitor
Device C1 repid discharge, the end PN voltage quickly reduce, therefore common by second resistance R2 and DC-bus voltage sampling circuit
Effect protection circuit.
It as shown in Figure 7a, is power input voltage negative half-cycle, controller 5 controls first switch tube Q1 conducting and second opens
Current flow diagram when closing pipe Q2 shutdown.The electric current of AC power source AC flows through first diode D1, first switch tube Q1, inductance
L1 and first resistor R1 flow back into AC power source AC, realizes the thermal energy storage process to inductance L1, while capacitor C1 is to load discharge
Energy is provided.First resistor R1 samples to obtain PFC inductive current-IL1 at this time.
It as shown in Figure 7b, is power input voltage negative half-cycle, controller 5 controls first switch tube Q1 shutdown and second opens
Current flow diagram when closing pipe Q2 conducting.The electric current of AC power source AC flows through first diode D1, capacitor C1, second resistance
R2, second switch Q2, inductance L1 and first resistor R1 flow back into AC power source AC, discharge the storage of inductance L1 under this state
Energy, while charging to capacitor C1.First resistor R1 samples to obtain PFC inductive current-IL2 at this time.5 basis of controller
PFC inductive current-IL1 and PFC inductive current-IL2 operation obtains PFC average current.
It as shown in Figure 7 c, is power input voltage negative half-cycle, first switch tube Q1 conducting and second switch Q2 conducting
When current flow diagram.Capacitor C1 simultaneously returns first switch tube Q1, second switch Q2 and second resistance R2 composition
Road, and the circuit electric discharge that load is constituted.Pass through second resistance R2 sampled power device branch current at this time；Simultaneously because capacitor
Device C1 repid discharge, the end PN voltage quickly reduce, therefore common by second resistance R2 and DC-bus voltage sampling circuit
Effect protection circuit.
It can be seen that using list resistance R1 as current sampling devices in PFC sample circuit in the present embodiment, using list
Resistance R2 realizes the protection of capacitor discharge short.It can be seen that component number is few in the present embodiment, circuit structure is simple, installs
The device volume of the circuit is small, at low cost and be easily achieved.
As shown in figure 8, one embodiment of the invention additionally provides a kind of air conditioner, adopted including the PFC in upper any embodiment
Sample circuit, the load end of the PFC sample circuit connect inverter circuit, and the inverter circuit connects compressor of air conditioner, controller
Including PFC control terminal and inverter circuit control terminal, the PFC control terminal connects semi-bridge switching circuit, the inverter circuit control
End connection inverter circuit.
Wherein, controller is outdoor controller, outdoor controller and indoor unit controller communication.The outdoor unit control
Device processed is from the PFC sample circuit input signal: AC-input voltage sampled value, DC bus-bar voltage sampled value, PFC electric current are adopted
Sample value, DC side protective current sampled value, indoor and outdoor communication signal and sensor signal, wherein sensor signal is by indoor unit
Controller is sent to outdoor controller.
In this way, according to compressor of air conditioner speed demand or the turn-on time of network voltage adjustment switching tube Q1 and Q2, in turn
Change PFC output voltage, meets frequency-conversion air-conditioning system circulation demand.
In the description of the present invention, it should be noted that the orientation or positional relationship of the instructions such as term " on ", "lower" is base
In orientation or positional relationship shown in the drawings, it is merely for convenience of description of the present invention and simplification of the description, rather than indication or suggestion
Signified device or element must have a particular orientation, be constructed and operated in a specific orientation, therefore should not be understood as to this
The limitation of invention.Unless otherwise clearly defined and limited, term " installation ", " connected ", " connection " shall be understood in a broad sense, example
Such as, it may be fixed connection or may be dismantle connection, or integral connection；It can be mechanical connection, be also possible to be electrically connected
It connects；It can be directly connected, the connection inside two elements can also be can be indirectly connected through an intermediary.For this
For the those of ordinary skill in field, the specific meanings of the above terms in the present invention can be understood according to specific conditions.
It should also be noted that, herein, relational terms such as first and second and the like are used merely to one
Entity or operation are distinguished with another entity or operation, without necessarily requiring or implying between these entities or operation
There are any actual relationship or orders.Moreover, the terms "include", "comprise" or its any other variant are intended to contain
Lid non-exclusive inclusion, so that the process, method, article or equipment including a series of elements is not only wanted including those
Element, but also including other elements that are not explicitly listed, or further include for this process, method, article or equipment
Intrinsic element.In the absence of more restrictions, the element limited by sentence "including a ...", it is not excluded that
There is also other identical elements in process, method, article or equipment including the element.
The above embodiments are merely illustrative of the technical solutions of the present invention, rather than its limitations；Although with reference to the foregoing embodiments
Invention is explained in detail, those skilled in the art should understand that: it still can be to aforementioned each implementation
Technical solution documented by example is modified or equivalent replacement of some of the technical features；And these modification or
Replacement, the spirit and scope for technical solution of various embodiments of the present invention that it does not separate the essence of the corresponding technical solution.
Claims (7)
1. a kind of PFC sample circuit, comprising: the first accumulator, semi-bridge switching circuit, rectification circuit, the second accumulator and
Controller；One end of AC power source connects one end of first accumulator, and the other end of the first accumulator connects half-bridge
Switching circuit, semi-bridge switching circuit, rectification circuit, the second accumulator and load are in parallel；The other end of AC power source connects
Rectification circuit, controller connect semi-bridge switching circuit；It is characterized by further comprising: current sampling circuit；The current sample electricity
Road is connect with the input terminal of the controller；
The current sampling circuit includes sampling resistor, is connected between the AC power source and first accumulator；
Two switching tubes of the semi-bridge switching circuit work in complementary fashion in every half of ac period, every half of alternating current
Period controls two switching tube timesharing conductings, realizes the charge and discharge of the first accumulator and the second accumulator, and pass through simultaneously
The sampling resistor obtains the current value in circuit；
Wherein, the semi-bridge switching circuit includes concatenated first switch tube and second switch, first accumulator
The common end of the first switch tube and the second switch is connected, the output end of the controller connects the first switch
The control terminal of pipe and the second switch；
The sampling resistor includes first resistor, and one end of the AC power source is connect with one end of the first resistor, described
The other end of first resistor is connect with first accumulator；The first resistor passes through operational amplifier and the controller
Input terminal connection；
In every half of ac period, when first switch tube disconnects and second switch is connected, the electric current of AC power source flows through the
One resistance, the first accumulator, second switch and rectification circuit flow back into AC power source, by controlling described in the first resistor
Device processed obtains the first sample rate current；When first switch tube conducting and second switch disconnection, the electric current of AC power source flows through first
Resistance, the first accumulator, first switch tube, the second accumulator and rectification circuit flow back into AC power source, pass through described
Controller described in one resistance obtains the second sample rate current；The controller is according to first sample rate current and the second sample rate current
Obtain PFC average current；
Wherein, the PFC sample circuit further include: short-circuit protection circuit；
One end of the short-circuit protection circuit is connect with the semi-bridge switching circuit, the other end of the short-circuit protection circuit and institute
The connection of the second accumulator is stated, and the short-circuit protection circuit is connect with the input terminal of the controller；
Wherein, the short-circuit protection circuit includes: second resistance；
One end of the second resistance is connect with the semi-bridge switching circuit, the other end of the second resistance and the rectified current
Road and second accumulator connection；The second resistance is connected by the input terminal of isolation operational amplifier and the controller
It connects；
When the first switch tube conducting and second switch conducting, second accumulator passes through the first switch
The shunt circuit of pipe, the second switch and the second resistance and the load is discharged, by described in the second resistance
Controller obtains power device branch current, and is used for discharge prevention.
2. PFC sample circuit according to claim 1, which is characterized in that the PFC sample circuit further include: exchange is defeated
Enter voltage sampling circuit and DC-bus voltage sampling circuit；The AC-input voltage sample circuit and DC bus electricity
Pressure sample circuit is connect with the input terminal of the controller；
The AC-input voltage sample circuit, is connected to the both ends of the AC power source, for acquiring AC-input voltage, and
It is sent to the controller；
The DC-bus voltage sampling circuit is connected to second accumulator both ends, for acquiring DC bus-bar voltage,
And it is sent to the controller.
3. PFC sample circuit according to claim 2, which is characterized in that the AC-input voltage sample circuit includes:
Three resistance, the 4th resistance and the first difference amplifier；
One end of the 3rd resistor is connect with the AC power source and the rectification circuit, the other end of the 3rd resistor with
The first input end of first difference amplifier connects；One end of 4th resistance and the AC power source and the sampling
Resistance connection, the other end of the 4th resistance are connect with the second input terminal of first difference amplifier；Described first is poor
The output end of amplifier is divided to connect with the input terminal of the controller.
4. PFC sample circuit according to claim 2, which is characterized in that the DC-bus voltage sampling circuit includes:
Five resistance, the 6th resistance, the 7th resistance, the 8th resistance, the 9th resistance, the tenth resistance and the second difference amplifier；Described 5th
One end of resistance is connect with one end of second accumulator, the other end of the 5th resistance and the one of the 6th resistance
First input of end connection, the other end of the 6th resistance and one end of the 7th resistance and second difference amplifier
End connection, the other end of the 7th resistance are connected to ground；One end of 8th resistance is another with second accumulator
One end connection, the other end of the 8th resistance connect with one end of the 9th resistance, the other end of the 9th resistance and
The connection of second input terminal of one end of the tenth resistance and second difference amplifier, the other end of the tenth resistance with
Ground connection；The output end of second difference amplifier is connect with the input terminal of the controller.
5. PFC sample circuit according to any one of claims 1 to 4, which is characterized in that the PFC sample circuit is also
It include: filter circuit；
One end of the filter circuit is connect with one end of the AC power source, and the other end of the filter circuit is exchanged with described
The other end of power supply connects.
6. PFC sample circuit according to any one of claims 1 to 4, which is characterized in that first accumulator is adopted
With inductance L；Second accumulator uses capacitor C.
7. a kind of air conditioner, which is characterized in that including PFC sample circuit according to any one of claims 1 to 6, the PFC
The load end of sample circuit connects inverter circuit, and the inverter circuit connects compressor of air conditioner, controller include PFC control terminal and
Inverter circuit control terminal, the PFC control terminal connect semi-bridge switching circuit, and the inverter circuit control terminal connects inverter circuit.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610494246.8A CN106026720B (en) | 2016-06-27 | 2016-06-27 | A kind of PFC sample circuit and air conditioner |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610494246.8A CN106026720B (en) | 2016-06-27 | 2016-06-27 | A kind of PFC sample circuit and air conditioner |
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| CN106026720A CN106026720A (en) | 2016-10-12 |
| CN106026720B true CN106026720B (en) | 2019-05-28 |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN107086770B (en) * | 2017-06-30 | 2023-03-31 | 广东美的制冷设备有限公司 | PFC circuit and variable frequency air conditioner |
| CN109980915A (en) * | 2019-05-17 | 2019-07-05 | 广东美的制冷设备有限公司 | Circuit of power factor correction and air conditioner |
| JP2022534367A (en) * | 2019-05-17 | 2022-07-29 | 広東美的制冷設備有限公司 | Power factor correction circuit and air conditioner |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN101128079B (en) * | 2006-08-16 | 2010-12-15 | 联昌电子企业股份有限公司 | Light tube driving system using electric isolation control |
| CN201839475U (en) * | 2010-03-16 | 2011-05-18 | 成都芯源系统有限公司 | LED dimming driving system |
| CN102130581B (en) * | 2011-03-30 | 2013-04-24 | 浙江工业大学 | BOOST PFC circuit based on nonlinear average current control |
| US20120314456A1 (en) * | 2011-06-09 | 2012-12-13 | Comarco Wireless Technologies, Inc. | Synchronous ac rectified flyback converter utilizing boost inductor |
| CN202395655U (en) * | 2011-12-08 | 2012-08-22 | 艾默生网络能源系统北美公司 | Sampling device of bridgeless PFC (positive feedback circuit) system |
| CN204721214U (en) * | 2015-06-15 | 2015-10-21 | 中兴通讯股份有限公司 | Pfc circuit and a kind of electronic equipment |
| CN105515415A (en) * | 2015-12-25 | 2016-04-20 | 美的集团武汉制冷设备有限公司 | Power conversion circuit, power conversion method and air conditioner |
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