CN204967243U - Current foldback circuit of variable frequency air conditioner and power factor correction PFC circuit - Google Patents

Current foldback circuit of variable frequency air conditioner and power factor correction PFC circuit Download PDF

Info

Publication number
CN204967243U
CN204967243U CN201520695862.0U CN201520695862U CN204967243U CN 204967243 U CN204967243 U CN 204967243U CN 201520695862 U CN201520695862 U CN 201520695862U CN 204967243 U CN204967243 U CN 204967243U
Authority
CN
China
Prior art keywords
pfc
output
current
circuit
resistance
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN201520695862.0U
Other languages
Chinese (zh)
Inventor
谭华泉
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
Original Assignee
Midea Group Co Ltd
Guangdong Midea Refrigeration Equipment Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Midea Group Co Ltd, Guangdong Midea Refrigeration Equipment Co Ltd filed Critical Midea Group Co Ltd
Priority to CN201520695862.0U priority Critical patent/CN204967243U/en
Application granted granted Critical
Publication of CN204967243U publication Critical patent/CN204967243U/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Abstract

The utility model discloses a current foldback circuit of variable frequency air conditioner and power factor correction PFC circuit, current foldback circuit includes: the PFC driver of drive PFC circuit, detect variable frequency air conditioner's the current detection unit of complete machine arrival current in order to generate detection voltage, the comparing element of first overcurrent protection signal is generated according to detection voltage, microcontroller, it is through first output PFC control signal to PFC driver to and through second output output compress machine control signal to compressor drive ware, carry out the electric current protection logic unit of logical operation in order to generate ultimate current guard signal according to first overcurrent protection signal and PFC control signal, wherein, the PFC driver drives the PFC circuit according to ultimate current guard signal and PFC control signal, and microcontroller controls the output state of first output and second output according to ultimate current guard signal simultaneously to can effectively protect the PFC circuit, avoid overcurrent protection's malfunction, avoid the compressor frequently to shut down.

Description

The current foldback circuit of convertible frequency air-conditioner and power factor correction pfc circuit
Technical field
The utility model relates to air-conditioning technical field, particularly the current foldback circuit of power factor correction pfc circuit and a kind of convertible frequency air-conditioner in a kind of convertible frequency air-conditioner.
Background technology
The application of convertible frequency air-conditioner is increasingly extensive, in order to reduce current harmonics, improve power factor, the electric-controlled plate of convertible frequency air-conditioner mostly have employed Active Power Factor Correction pfc circuit, but complete machine input current overcurrent easily causes the power switch pipe in pfc circuit to damage.
In the related; overcurrent protection strategy below usual employing: when complete machine input current exceedes current protection threshold value; turn off the drive singal of pfc circuit and turn off the drive singal of compressor; to prevent power switch pipe in pfc circuit because of overcurrent damage, reduce input current by close compressor simultaneously.But its shortcoming existed is, when grid voltage mutation, easily triggers the misoperation of overcurrent protection, cause high frequent to be shut down.
Utility model content
The utility model is intended to solve one of technical problem in correlation technique at least to a certain extent.For this reason, an object of the present utility model is the current foldback circuit proposing power factor correction pfc circuit in a kind of convertible frequency air-conditioner, and this circuit can available protecting pfc circuit, and avoids the misoperation of overcurrent protection.
Another object of the present utility model is to propose a kind of convertible frequency air-conditioner.
For achieving the above object, the utility model proposes the current foldback circuit of power factor correction pfc circuit in a kind of convertible frequency air-conditioner on the one hand, described convertible frequency air-conditioner comprises described pfc circuit, the rectification circuit be connected with the input of described pfc circuit, the compressor be connected with the output of described pfc circuit and the compressor drive driving described compressor, and described current foldback circuit comprises: the PFC driver driving described pfc circuit; In order to detect the complete machine input current of described convertible frequency air-conditioner to generate the current detecting unit detecting voltage; The comparing unit be connected with described current detecting unit, described comparing unit is in order to generate first overcurrent protection signal according to described detection voltage; Microcontroller, described microcontroller controls signal to described PFC driver in order to export PFC by the first output, and by the second output output squeezing machine control signal to described compressor drive; The current protection logical block be connected with described microcontroller with described comparing unit respectively, described current protection logical block is in order to carry out logical operation to generate ultimate current guard signal according to described first overcurrent protection signal and described PFC control signal; Wherein, described PFC driver drives described pfc circuit according to described ultimate current guard signal and described PFC control signal, and described microcontroller controls the output state of described first output and the second output according to described ultimate current guard signal simultaneously.
According to the current foldback circuit of the power factor correction pfc circuit that the utility model proposes, by current protection logical block, logical operation is carried out to generate ultimate current guard signal to first overcurrent protection signal and PFC control signal, PFC driver drives pfc circuit according to ultimate current guard signal and PFC control signal afterwards, microcontroller controls the output state of the first output and the second output according to ultimate current guard signal simultaneously, thus can available protecting pfc circuit, pfc circuit is avoided to damage because of overcurrent, and avoid the misoperation of overcurrent protection, avoid compressor because of grid voltage mutation frequent shutdown.
Particularly; described current protection logical block is carried out and logical operation according to described first overcurrent protection signal and described PFC control signal; described current protection logical block comprises: with logic chip; describedly to be connected with the output of described comparing unit with the first input end of logic chip; describedly to be connected with the first output of described microcontroller with the second input of logic chip, to be describedly connected with the input of described microcontroller with described PFC driver respectively with the output of logic chip.
Particularly; described current protection logical block is carried out and logical operation according to described first overcurrent protection signal and described PFC control signal; described current protection logical block comprises: triple gate; the input of described triple gate is connected with the output of described comparing unit; the Enable Pin of described triple gate is connected with the first output of described microcontroller, and the output of described triple gate is connected with the input of described microcontroller with described PFC driver respectively.
Particularly; described current protection logical block is carried out and logical operation according to described first overcurrent protection signal and described PFC control signal; described current protection logical block comprises: digital switch chip; the input of described digital switch chip is connected with the output of described comparing unit; the Enable Pin of described digital switch chip is connected with the first output of described microcontroller, and the output of described digital switch chip is connected with the input of described microcontroller with described PFC driver respectively.
Further; described comparing unit comprises: the first comparator; the positive input terminal of described first comparator is connected with described current detecting unit; the negative input end of described first comparator is connected with the providing end of default protection voltage, and the output of described first comparator is as the output of described comparing unit.
Or described comparing unit comprises: the first resistance, one end and first of described first resistance is preset power supply and is connected; Second resistance, one end of described second resistance is connected with the other end of described first resistance; 3rd resistance, one end of described 3rd resistance is connected with the other end of described second resistance, and have first node between described 3rd resistance and described second resistance, described first node is connected with described current detecting unit; 4th resistance, one end of described 4th resistance is connected with the other end of described first resistance; 5th resistance, ground connection after one end of described 5th resistance is connected with the other end of described 4th resistance; Second comparator, the positive input terminal of described second comparator is connected with the other end of described 3rd resistance, and the negative input end of described second comparator is connected with the other end of described 5th resistance; 3rd comparator; the positive input terminal of described 3rd comparator is connected with the output of described second comparator; the negative input end of described 3rd comparator is connected with the providing end of default protection voltage, and the output of described 3rd comparator is as the output of described comparing unit.
Further, described rectification circuit has the first output and the second output, described pfc circuit has first input end and the second input, first output of described rectification circuit is connected with the first input end of described pfc circuit, ground connection after second output of described rectification circuit is connected with the second input of described pfc circuit, described current detecting unit comprises: sampling resistor, and described sampling resistor is connected between the second output of described rectification circuit and the second input of described pfc circuit.
Further, described pfc circuit comprises inductance, diode and power switch pipe, and wherein, the control pole of described power switch pipe is connected with described PFC driver.
For achieving the above object, the utility model proposes a kind of convertible frequency air-conditioner on the other hand, comprises the current foldback circuit of described power factor correction pfc circuit.
According to the convertible frequency air-conditioner that the utility model proposes, by the current foldback circuit of pfc circuit, can available protecting pfc circuit, avoid pfc circuit to damage because of overcurrent, and avoid the misoperation of overcurrent protection, avoid compressor because of grid voltage mutation frequent shutdown.
Accompanying drawing explanation
Fig. 1 is the block diagram of the current foldback circuit of power factor correction pfc circuit in the convertible frequency air-conditioner according to the utility model embodiment;
Fig. 2 is the circuit theory diagrams of the current foldback circuit of power factor correction pfc circuit in the convertible frequency air-conditioner according to the utility model embodiment;
Fig. 3 is the circuit theory diagrams of the current foldback circuit of power factor correction pfc circuit in the convertible frequency air-conditioner according to another embodiment of the utility model;
Fig. 4 is the circuit theory diagrams of the current foldback circuit of power factor correction pfc circuit in the convertible frequency air-conditioner according to another embodiment of the utility model; And
Fig. 5 is the circuit theory diagrams of the comparing unit according to another embodiment of the utility model.
Embodiment
Be described below in detail embodiment of the present utility model, the example of described embodiment is shown in the drawings, and wherein same or similar label represents same or similar element or has element that is identical or similar functions from start to finish.Be exemplary below by the embodiment be described with reference to the drawings, be intended to for explaining the utility model, and can not be interpreted as restriction of the present utility model.
Below with reference to the accompanying drawings the current foldback circuit of power factor correction PFC (PowerFactorCorrection, power factor correction) circuit in the convertible frequency air-conditioner and convertible frequency air-conditioner that the utility model embodiment proposes is described.
Wherein, according to the example of Fig. 1-4, convertible frequency air-conditioner can comprise rectification circuit 10, pfc circuit 20, compressor 30 and compressor drive 31, wherein, the input of rectification circuit 10 is connected with AC power AC, and rectification circuit 10 carries out rectification to obtain the direct current after rectification for the alternating current provided AC power AC; The input of pfc circuit 20 is connected with the output of rectification circuit 10, and the output of pfc circuit 20 is connected with compressor 30, and pfc circuit 20 is for carrying out power factor correction to power supply; Compressor drive 31 is connected with compressor 30, and compressor drive 31 is for driving compressor 30, and particularly, compressor drive 31 drives compressor 30 by the intelligent power module of compressor 30.In addition, electrochemical capacitor E1 is also parallel with between pfc circuit 20 and load 30.
That is, AC power AC is through the uncontrollable full-wave rectification of rectification circuit 10, and the alternating current AC then after rectification, through the power factor correction of pfc circuit 20, outputs to jumbo electrochemical capacitor E1, compressor etc.
Particularly, pfc circuit 20 can adopt Boost type pfc circuit.As in Figure 2-4, rectification circuit 10 has the first output and the second output, Boost type pfc circuit can comprise inductance L 1, power switch tube S 1 and diode D1, wherein, one end of inductance L 1 is connected with the first output of rectification circuit 10, the other end of inductance L 1 is connected with the anode of diode D1, has the 3rd node between inductance L 1 and diode D1; The negative electrode of diode D1 is connected with the positive terminal of electrochemical capacitor E1; The collector electrode of power switch tube S 1 is connected with the 3rd node, and the emitter of power switch tube S 1 is connected with the negative pole end of electrochemical capacitor E1 with the second output of rectification circuit 10 respectively.
In the embodiment of Fig. 2-4, pfc circuit 20 also can carry out boosting process to the direct current after rectification while carrying out power factor correction to power supply, think that electrochemical capacitor E1 and load 30 provide galvanic current pressure, wherein, by controlling the duty ratio of power switch tube S 1, the object improving power factor and boosting can be reached.
As Figure 1-4, in the convertible frequency air-conditioner of the utility model embodiment, the current foldback circuit 40 of power factor correction pfc circuit comprises: PFC driver 401, current detecting unit 402, comparing unit 403, microcontroller 404 and current protection logical block 405.
Wherein, PFC driver 401, for driving pfc circuit 20, namely says that PFC driver 401 is connected with to pfc circuit 20 output drive signal with pfc circuit 20.Particularly, in the embodiment of Fig. 2-4, pfc circuit 20 comprises inductance L 1, diode D1 and power switch tube S 1, PFC driver 401 and the control of power switch tube S 1 and is extremely connected and opens with driving power switching tube S1 or turn off.
Current detecting unit 402 detects voltage in order to the complete machine input current detecting convertible frequency air-conditioner to generate, and that is, current detecting unit 402 can detect complete machine input current and is converted to by complete machine input current and detect voltage accordingly.Wherein, it should be noted that, in the embodiment of Fig. 2-4, current detecting unit 402 can be connected with compressor 30 etc. with power switch tube S 1, electrochemical capacitor E1, and complete machine input current can be the electric current sum flowing through power switch tube S 1 in pfc circuit 20, electrochemical capacitor E1 and compressor 30 etc.Particularly, when the power switch tube S 1 in pfc circuit 20 is opened, complete machine input current equals the electric current flowing through power switch tube S 1; When power switch tube S 1 in pfc circuit 20 turns off, complete machine input current equals the charging and discharging currents of electrochemical capacitor E1 and flows through the electric current sum of compressor 30.
Comparing unit 403 is connected with current detecting unit 402, and comparing unit 403, in order to generate first overcurrent protection signal according to detection voltage, is namely sayed that comparing unit 403 can be connected with the output of current detecting unit 402 and detected voltage to obtain.It should be noted that; first overcurrent protection signal can comprise effectively first overcurrent protection signal and invalid first overcurrent protection signal; comparing unit 403 detects when voltage is greater than and presets and protect voltage in judgement and exports effective first overcurrent protection signal, and exports invalid first overcurrent protection signal when judging that detection voltage is less than or equal to and presets and protect voltage.
Microcontroller 404 is connected with PFC driver 401 by the first output OUT1, microcontroller 404 is also connected with compressor drive 31 by the second output OUT2, microcontroller 404 controls signal to PFC driver 401 in order to export PFC by the first output OUT1, and by the second output OUT2 output squeezing machine control signal to compressor drive 31.Particularly, control signal can comprise effective control signal and invalid control signal, when microcontroller 40 export effective PFC control signal to PFC driver 401 time, PFC driver 401 drives the power switch tube S 1 in pfc circuit 20 open-minded, when microcontroller 40 export invalid PFC control signal to PFC driver 401 time, PFC driver 401 driving power switching tube S1 turns off; Drive compressor start when microcontroller 40 exports effective compressor control signal to compressor drive during compressor drive 31 31, drive compressor shutdown when microcontroller 40 exports invalid compressor control signal to compressor drive during compressor drive 31 31.
Current protection logical block 405 is connected with microcontroller 404 with comparing unit 403 respectively, and current protection logical block 405 is in order to carry out logical operation to generate ultimate current guard signal according to first overcurrent protection signal and PFC control signal.Namely say, the first input end of current protection logical block 405 and comparing unit 403 are to receive first overcurrent protection signal, and the second input of current protection logical block 405 is connected to obtain PFC control signal with the first output OUT1 of microcontroller 404.It should be noted that; ultimate current guard signal comprises effective ultimate current guard signal and invalid ultimate current guard signal; that is, current protection logical block 405 judges whether to generate effective ultimate current guard signal according to the logic operation result between first overcurrent protection signal and PFC control signal.
Wherein, PFC driver 401 drives pfc circuit according to ultimate current guard signal and PFC control signal, and microcontroller 404 controls the output state of the first output and the second output according to ultimate current guard signal simultaneously.It should be noted that; when current protection logical block 405 exports effective ultimate current guard signal; no matter whether PFC control signal is effective; PFC driver 401 all drives the power switch tube S 1 in pfc circuit 20 to turn off; simultaneously microcontroller 404 controls the first output and the second output closes stops output PFC control signal and compressor control signal when receiving ultimate current guard signal, thus available protecting power switch pipe.
Also it should be noted that, PFC driver 401 receive invalid final overcurrent protection signal and effectively PFC drive singal time just driving power switching tube S1 is open-minded, otherwise PFC driver 401 driving power switching tube S1 turns off.
Specifically; when microcontroller 404 exports effective PFC control signal; PFC driver 401 drives the device for power switching S1 of pfc circuit 20 open-minded; electric current flows through current detecting unit 402; current detecting unit 402 exports the corresponding voltage that detects to comparing unit 403 according to the complete machine input current detected; wherein; detect voltage proportional in complete machine input current; if complete machine input current generation overcurrent; then detect voltage and exceed default protection voltage, comparing unit 403 will export effectively first overcurrent protection signal.
Current protection logical block 405 makes the following judgment after receiving effectively first overcurrent protection signal:
If judge to receive effective PFC control signal, namely effectively first overcurrent protection signal produces in the effective situation of PFC control signal, can judge that overcurrent causes by the electric current of power switch tube S 1 is excessive, current protection logical block 405 exports effectively final overcurrent protection signal, this effectively final overcurrent protection signal outputs to PFC driver 401 and turns off to make PFC driver 401 driving power switching device S1, this effectively final overcurrent protection signal outputs to microcontroller 404 simultaneously, stop making microcontroller 404 exporting PFC control signal and compressor control signal, to protect device for power switching,
If judge to receive invalid PFC control signal, namely effectively first overcurrent protection signal produces when PFC control signal is invalid, although complete machine input current is excessive, comparing unit 403 exports effectively first overcurrent protection signal, but current protection logical block 405 but exports invalid final overcurrent protection signal, PFC driver 401 driving power switching device S1 turns off, microcontroller 404 continues to export PFC control signal and compressor control signal simultaneously, protection by mistake can not be there is, avoid compressor power switch pipe turn off device because of grid voltage mutation frequent shutdown.
In addition; if there is not overcurrent in complete machine input current; then detect voltage lower than default protection voltage; comparing unit 403 will export invalid first overcurrent protection signal; current protection logical block 405 exports invalid ultimate current guard signal; microcontroller 404 is normal after receiving invalid ultimate current guard signal exports PFC control signal and compressor control signal, simultaneously PFC driver 401 after receiving invalid ultimate current guard signal according to the PFC control signal driving power switching device S1 that microcontroller 404 exports.
Be understandable that, microcontroller 404 also can detect the voltage of DC bus-bar voltage and electrochemical capacitor E1, and controls signal to PFC driver 401 to control the duty ratio of power switch tube S 1 according to complete machine input current and DC bus-bar voltage output PFC.Further, microcontroller 404 also can according to the machine running status output squeezing machine control signal of convertible frequency air-conditioner to driven compressor 31 to control the running frequency of compressor 30.
As mentioned above, at complete machine input current overcurrent and power switch tube S 1 is opened time PFC driver 401 driving power switching device S1 turn off, microcontroller 404 stops exporting PFC control signal and compressor control signal; At complete machine input current overcurrent and power switch tube S 1 turns off time, microcontroller 404 continues to export PFC control signal and compressor control signal, and namely device for power switching S1 is in off state, and compressor 30 normally runs.
Thus, the current foldback circuit of the utility model embodiment can available protecting pfc circuit, avoids pfc circuit to damage because of overcurrent, and avoids the misoperation of overcurrent protection, avoid compressor because of grid voltage mutation frequent shutdown.
Particularly; according to the embodiment of Fig. 2-4; comparing unit 403 comprises: the first comparator LM1; the positive input terminal of the first comparator LM1 is connected with current detecting unit 402; the negative input end of the first comparator LM1 is connected with the providing end Vref of default protection voltage, and the output of the first comparator LM1 is connected with current protection logical block 405 as the output of comparing unit 402.
It should be noted that, comprising inductance L 1, in the pfc circuit 20 of power switch tube S 1 and diode D1, the shock-resistant current capacity of inductance L 1 and diode D1 is much bigger compared with power switch tube S 1, the rated current of such as power switch tube S 1 selects 30A according to the power grade of convertible frequency air-conditioner, and diode can bear 90A impulse current, like this, preset protection voltage to set according to the conveyance capacity of power switch tube S 1, such as make full use of the ability of power switch pipe for guarantee and do not damage power switch pipe, overcurrent protection threshold value can be set as 25A, and then determine to preset protection voltage according to overcurrent protection threshold value.
Specifically, when complete machine input current is greater than overcurrent protection threshold value, the detection voltage that current detecting unit 402 exports is greater than presets protection voltage, and the first comparator LM1 exports high level signal, and this high level signal is effectively first overcurrent protection signal; When complete machine input current is less than or equal to overcurrent protection threshold value, the detection voltage that current detecting unit 402 exports is less than or equal to presets protection voltage, and the first comparator LM1 output low level signal, this low level signal is invalid first overcurrent protection signal.
Or as the example of Fig. 5, comparing unit 403 can comprise: the first resistance R1, the second resistance R2, the 3rd resistance R2, the 4th resistance R4, the 5th resistance R5, the second comparator LM2 and the 3rd comparator LM3.
Wherein, the first resistance R1 one end and first preset power supply vcc be connected; One end of second resistance R4 is connected with the other end of the first resistance R1; One end of 3rd resistance R3 is connected with the other end of the second resistance R2, and have first node between the 3rd resistance R3 and the second resistance R2, first node is connected with current detecting unit 402; One end of 4th resistance R4 is connected with the other end of the first resistance R1; Ground connection after one end of 5th resistance R5 is connected with the other end of the 4th resistance R4; The positive input terminal of the second comparator LM2 is connected with the other end of the 3rd resistance R3, and the negative input end of the second comparator LM is connected with the other end of the 5th resistance R5; The positive input terminal of the 3rd comparator LM3 is connected with the output of the second comparator LM2; the negative input end of the 3rd comparator LM3 is connected with the providing end Vref of default protection voltage, and the output of the 3rd comparator LM3 is connected with current protection logical block 405 as the output of comparing unit 403.
And; comparing unit 403 can comprise: the 6th resistance R6 and the 7th resistance R7; one end and second of 6th resistance R6 is preset power supply vdd and is connected; one end of 7th resistance R7 is connected with the other end of the 6th resistance R6; the other end ground connection of the 7th resistance R7; have Section Point between 6th resistance R6 and the 7th resistance R7, Section Point is as the providing end Vref of default protection voltage.That is, the 6th resistance R6 and the 7th resistance R7 carries out dividing potential drop to the voltage that second presets power supply vdd, and the voltage after dividing potential drop is provided as the negative input end preset and protect voltage to be supplied to the 3rd comparator LM3.
Specifically, when complete machine input current is greater than overcurrent protection threshold value, the detection voltage that current detecting unit 402 exports by comparing unit 403 relatively after, the 3rd comparator LM3 exports high level signal, and this high level signal be effective for the first time overcurrent protection signal; When complete machine input current is less than or equal to overcurrent protection threshold value, current detecting unit 402 export detection voltage by comparing unit 403 relatively after, the 3rd comparator LM3 output low level signal, this low level signal is invalid first overcurrent protection signal.
According to embodiment of the present utility model, current protection logical block 405 is carried out and logical operation according to first overcurrent protection signal and PFC control signal.Suppose that effective PFC control signal is high level signal, invalid PFC control signal is low level signal, so, the first comparator LM1 is comprised for comparing unit 403, when the first comparator LM1 exports high level signal and microcontroller 404 exports high level signal, current protection logical block 405 is by exporting high level signal with logical operation, and this high level signal is effectively final overcurrent protection signal; And when the first comparator LM1 output low level signal or microcontroller 404 output low level signal, current protection logical block 405 by with logical operation output low level signal, this low level signal is invalid final overcurrent protection signal.
Further, according to embodiment of the present utility model, current protection logical block 405 can be with logic chip, triple gate, digital switch chip or other there is the circuit structure with logic function.
As shown in Figure 2; current protection logical block 405 can comprise: with logic chip IC1; be connected with the output i.e. output of the first comparator LM1 or the 3rd comparator LM3 of comparing unit 403 with the first input end a11 of logic chip IC1; be connected with the first output OUT1 of microcontroller 404 with the second input a12 of logic chip IC1, be connected with the input IN of microcontroller 404 with PFC driver 401 respectively with the output b1 of logic chip IC1.That is, ultimate current guard signal can be outputted to PFC driver 401 with the output of logic chip IC1, ultimate current guard signal be outputted to microcontroller 404 simultaneously.
According to a concrete example of the present utility model, 74LS08 can be preferably with the model of logic chip IC1.
As shown in Figure 3; current protection logical block comprises: triple gate IC2; the input a2 of triple gate IC2 and the output of the comparing unit 403 i.e. output of the first comparator LM1 or the 3rd comparator LM3 is connected; the Enable Pin ENB1 of triple gate IC2 is connected with the first output OUT1 of microcontroller 404, and the output b2 of triple gate IC2 is connected with the input IN of microcontroller 404 with PFC driver 401 respectively.That is, ultimate current guard signal can be outputted to PFC driver 401 by the output of triple gate IC2, ultimate current guard signal is outputted to microcontroller 404 simultaneously.
According to a concrete example of the present utility model, the model of triple gate IC2 can be preferably 74LS125.
As shown in Figure 4; current protection logical block 405 comprises: digital switch chip IC 3; the input a3 of digital switch chip IC 3 and the output of the comparing unit 403 i.e. output of the first comparator LM1 or the 3rd comparator LM3 is connected; the Enable Pin ENB2 of digital switch chip IC 3 is connected with the first output of microcontroller 404, and the output of digital switch chip IC 3 is connected with the input of PFC driver 401 with microcontroller 404 respectively.That is, ultimate current guard signal can be outputted to PFC driver 401 by the output b3 of digital switch chip IC 3, ultimate current guard signal is outputted to microcontroller 404 simultaneously.
According to a concrete example of the present utility model, the model of digital switch chip IC 3 can be preferably SN74CBTD3305C, SN74CBT3126.
In addition, according to the embodiment of Fig. 2-4, rectification circuit 10 has the first output and the second output, pfc circuit 20 has first input end and the second input, first output of rectification circuit 10 is connected with the first input end of pfc circuit 20, ground connection after second output of rectification circuit 10 is connected with the second input of pfc circuit 20, current detecting unit 402 comprises: sampling resistor R1, and sampling resistor R1 is connected between the second output of rectification circuit 10 and the second input of pfc circuit 20.
That is; one end r1 of sampling resistor R1 is connected with the negative terminal of the IPM module of compressor 30 with the emitter of power switch tube S 1, the negative pole end of electrochemical capacitor E1 respectively; ground connection after the other end r2 of sampling resistor R1 is connected with the second output of rectification circuit 10; wherein; second output of rectification circuit 10 is the reference ground of current foldback circuit, is namely the reference ground presetting protection voltage.
And, one end r1 of sampling resistor R1 also can be connected with comparing unit 403, particularly, one end r1 of sampling resistor R1 can be connected with the positive input terminal of the first comparator LM1, or one end r1 of sampling resistor R1 can be connected with the first node between the second resistance R2 with the 3rd resistance R3, like this, by sampling resistor R1, complete machine input current is converted to detection voltage, and detection voltage is exported to comparing unit 403.
In sum, according to the current foldback circuit of the power factor correction pfc circuit that the utility model embodiment proposes, by current protection logical block, logical operation is carried out to generate ultimate current guard signal to first overcurrent protection signal and PFC control signal, PFC driver drives pfc circuit according to ultimate current guard signal and PFC control signal afterwards, microcontroller controls the output state of the first output and the second output according to ultimate current guard signal simultaneously, thus can available protecting pfc circuit, pfc circuit is avoided to damage because of overcurrent, and avoid the misoperation of overcurrent protection, avoid compressor because of grid voltage mutation frequent shutdown.
Finally, the utility model embodiment also proposed a kind of convertible frequency air-conditioner, comprises the current foldback circuit of the power factor correction pfc circuit of above-described embodiment.
According to the convertible frequency air-conditioner that the utility model embodiment proposes; by the current foldback circuit of pfc circuit, can available protecting pfc circuit, avoid pfc circuit to damage because of overcurrent; and avoid the misoperation of overcurrent protection, avoid compressor because of grid voltage mutation frequent shutdown.
In description of the present utility model, it will be appreciated that, term " " center ", " longitudinal direction ", " transverse direction ", " length ", " width ", " thickness ", " on ", D score, " front ", " afterwards ", " left side ", " right side ", " vertically ", " level ", " top ", " end " " interior ", " outward ", " clockwise ", " counterclockwise ", " axis ", " radial direction ", orientation or the position relationship of the instruction such as " circumference " are based on orientation shown in the drawings or position relationship, only the utility model and simplified characterization for convenience of description, instead of indicate or imply that the device of indication or element must have specific orientation, with specific azimuth configuration and operation, therefore can not be interpreted as restriction of the present utility model.
In addition, term " first ", " second " only for describing object, and can not be interpreted as instruction or hint relative importance or imply the quantity indicating indicated technical characteristic.Thus, be limited with " first ", the feature of " second " can express or impliedly comprise at least one this feature.In description of the present utility model, the implication of " multiple " is at least two, such as two, three etc., unless otherwise expressly limited specifically.
In the utility model, unless otherwise clearly defined and limited, the term such as term " installation ", " being connected ", " connection ", " fixing " should be interpreted broadly, and such as, can be fixedly connected with, also can be removably connect, or integral; Can be mechanical connection, also can be electrical connection; Can be directly be connected, also indirectly can be connected by intermediary, can be the connection of two element internals or the interaction relationship of two elements, unless otherwise clear and definite restriction.For the ordinary skill in the art, the concrete meaning of above-mentioned term in the utility model can be understood as the case may be.
In the utility model, unless otherwise clearly defined and limited, fisrt feature second feature " on " or D score can be that the first and second features directly contact, or the first and second features are by intermediary indirect contact.And, fisrt feature second feature " on ", " top " and " above " but fisrt feature directly over second feature or oblique upper, or only represent that fisrt feature level height is higher than second feature.Fisrt feature second feature " under ", " below " and " below " can be fisrt feature immediately below second feature or tiltedly below, or only represent that fisrt feature level height is less than second feature.
In the description of this specification, specific features, structure, material or feature that the description of reference term " embodiment ", " some embodiments ", " example ", " concrete example " or " some examples " etc. means to describe in conjunction with this embodiment or example are contained at least one embodiment of the present utility model or example.In this manual, to the schematic representation of above-mentioned term not must for be identical embodiment or example.And the specific features of description, structure, material or feature can combine in one or more embodiment in office or example in an appropriate manner.In addition, when not conflicting, the feature of the different embodiment described in this specification or example and different embodiment or example can carry out combining and combining by those skilled in the art.
Although illustrate and described embodiment of the present utility model above, be understandable that, above-described embodiment is exemplary, can not be interpreted as restriction of the present utility model, those of ordinary skill in the art can change above-described embodiment, revises, replace and modification in scope of the present utility model.

Claims (9)

1. the current foldback circuit of power factor correction pfc circuit in a convertible frequency air-conditioner; it is characterized in that; described convertible frequency air-conditioner comprises described pfc circuit, the rectification circuit be connected with the input of described pfc circuit, the compressor be connected with the output of described pfc circuit and the compressor drive driving described compressor, and described current foldback circuit comprises:
Drive the PFC driver of described pfc circuit;
In order to detect the complete machine input current of described convertible frequency air-conditioner to generate the current detecting unit detecting voltage;
The comparing unit be connected with described current detecting unit, described comparing unit is in order to generate first overcurrent protection signal according to described detection voltage;
Microcontroller, described microcontroller controls signal to described PFC driver in order to export PFC by the first output, and by the second output output squeezing machine control signal to described compressor drive;
The current protection logical block be connected with described microcontroller with described comparing unit respectively, described current protection logical block is in order to carry out logical operation to generate ultimate current guard signal according to described first overcurrent protection signal and described PFC control signal;
Wherein, described PFC driver drives described pfc circuit according to described ultimate current guard signal and described PFC control signal, and described microcontroller controls the output state of described first output and the second output according to described ultimate current guard signal simultaneously.
2. the current foldback circuit of power factor correction pfc circuit according to claim 1; it is characterized in that; described current protection logical block is carried out and logical operation according to described first overcurrent protection signal and described PFC control signal, and described current protection logical block comprises:
With logic chip, describedly to be connected with the output of described comparing unit with the first input end of logic chip, describedly to be connected with the first output of described microcontroller with the second input of logic chip, to be describedly connected with the input of described microcontroller with described PFC driver respectively with the output of logic chip.
3. the current foldback circuit of power factor correction pfc circuit according to claim 1; it is characterized in that; described current protection logical block is carried out and logical operation according to described first overcurrent protection signal and described PFC control signal, and described current protection logical block comprises:
Triple gate, the input of described triple gate is connected with the output of described comparing unit, the Enable Pin of described triple gate is connected with the first output of described microcontroller, and the output of described triple gate is connected with the input of described microcontroller with described PFC driver respectively.
4. the current foldback circuit of power factor correction pfc circuit according to claim 1; it is characterized in that; described current protection logical block is carried out and logical operation according to described first overcurrent protection signal and described PFC control signal, and described current protection logical block comprises:
Digital switch chip, the input of described digital switch chip is connected with the output of described comparing unit, the Enable Pin of described digital switch chip is connected with the first output of described microcontroller, and the output of described digital switch chip is connected with the input of described microcontroller with described PFC driver respectively.
5. the current foldback circuit of the power factor correction pfc circuit according to any one of claim 1-4, is characterized in that, described comparing unit comprises:
First comparator, the positive input terminal of described first comparator is connected with described current detecting unit, and the negative input end of described first comparator is connected with the providing end of default protection voltage, and the output of described first comparator is as the output of described comparing unit.
6. the current foldback circuit of the power factor correction pfc circuit according to any one of claim 1-4, is characterized in that, described comparing unit comprises:
First resistance, one end and first of described first resistance is preset power supply and is connected;
Second resistance, one end of described second resistance is connected with the other end of described first resistance;
3rd resistance, one end of described 3rd resistance is connected with the other end of described second resistance, and have first node between described 3rd resistance and described second resistance, described first node is connected with described current detecting unit;
4th resistance, one end of described 4th resistance is connected with the other end of described first resistance;
5th resistance, ground connection after one end of described 5th resistance is connected with the other end of described 4th resistance;
Second comparator, the positive input terminal of described second comparator is connected with the other end of described 3rd resistance, and the negative input end of described second comparator is connected with the other end of described 5th resistance;
3rd comparator; the positive input terminal of described 3rd comparator is connected with the output of described second comparator; the negative input end of described 3rd comparator is connected with the providing end of default protection voltage, and the output of described 3rd comparator is as the output of described comparing unit.
7. the current foldback circuit of power factor correction pfc circuit according to claim 1; it is characterized in that; described rectification circuit has the first output and the second output; described pfc circuit has first input end and the second input; first output of described rectification circuit is connected with the first input end of described pfc circuit; ground connection after second output of described rectification circuit is connected with the second input of described pfc circuit, described current detecting unit comprises:
Sampling resistor, described sampling resistor is connected between the second output of described rectification circuit and the second input of described pfc circuit.
8. the current foldback circuit of power factor correction pfc circuit according to claim 1, is characterized in that, described pfc circuit comprises inductance, diode and power switch pipe, and wherein, the control pole of described power switch pipe is connected with described PFC driver.
9. a convertible frequency air-conditioner, is characterized in that, comprises the current foldback circuit of the power factor correction pfc circuit according to any one of claim 1-8.
CN201520695862.0U 2015-09-08 2015-09-08 Current foldback circuit of variable frequency air conditioner and power factor correction PFC circuit Active CN204967243U (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201520695862.0U CN204967243U (en) 2015-09-08 2015-09-08 Current foldback circuit of variable frequency air conditioner and power factor correction PFC circuit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201520695862.0U CN204967243U (en) 2015-09-08 2015-09-08 Current foldback circuit of variable frequency air conditioner and power factor correction PFC circuit

Publications (1)

Publication Number Publication Date
CN204967243U true CN204967243U (en) 2016-01-13

Family

ID=55062284

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201520695862.0U Active CN204967243U (en) 2015-09-08 2015-09-08 Current foldback circuit of variable frequency air conditioner and power factor correction PFC circuit

Country Status (1)

Country Link
CN (1) CN204967243U (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106655102A (en) * 2016-10-31 2017-05-10 广东美的制冷设备有限公司 Power factor corrector over-current protection device and home appliance
CN106655101A (en) * 2016-10-31 2017-05-10 广东美的制冷设备有限公司 Household electrical appliance and over-current protection device and method of power factor corrector
CN108306541A (en) * 2018-02-10 2018-07-20 广东美的制冷设备有限公司 IPM modules and household electrical appliance

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106655102A (en) * 2016-10-31 2017-05-10 广东美的制冷设备有限公司 Power factor corrector over-current protection device and home appliance
CN106655101A (en) * 2016-10-31 2017-05-10 广东美的制冷设备有限公司 Household electrical appliance and over-current protection device and method of power factor corrector
CN108306541A (en) * 2018-02-10 2018-07-20 广东美的制冷设备有限公司 IPM modules and household electrical appliance

Similar Documents

Publication Publication Date Title
CN105337262A (en) Variable frequency air conditioner and over-current protective circuit of power factor correction (PFC) circuit
CN204967243U (en) Current foldback circuit of variable frequency air conditioner and power factor correction PFC circuit
CN105024539B (en) The short time voltage of single phase alternating current power supply interrupts countermeasure and device
CN103000964B (en) Controller of battery management system
CN103123882B (en) Intelligent controller of bistable permanent-magnet vacuum circuit breaker
CN202888791U (en) Load controller based on zero-cross starting overvoltage protection
CN104633861B (en) A kind of convertible frequency air-conditioner and its power-supplying circuit
CN102487211B (en) Battery charging equipment
CN102638037B (en) The method for controlling power supply of communication equipment, system and electric power system
CN107895992A (en) A kind of solar storage battery charge-discharge monitoring system
CN204967657U (en) Discharge device of dc -to -ac converter and dc -to -ac converter
CN204290399U (en) Based on the intelligent track-traffic high-voltage charging machine of touch-screen
CN208508520U (en) Discharge circuit, driving plate, controller and air-conditioning
CN203690904U (en) Self-protection online direct-current output circuit
CN103023135A (en) Multi-level direct current transformation power supply device
CN2595040Y (en) Digital electronic protector of motor
CN109245537A (en) A kind of holding circuit of airborne power supply modules
CN205583660U (en) Output current foldback circuit of converter
CN108230983A (en) The method for managing power supply of display screen
CN2753031Y (en) Intelligent leakage release
CN106655102A (en) Power factor corrector over-current protection device and home appliance
CN211606083U (en) Short-circuit protection circuit of IPM circuit, drive circuit and electronic equipment
CN207819553U (en) Power supply management device for frame circuit breaker controller
CN206546404U (en) A kind of level pressure power amplifier short-circuit detecting circuit based on comparator
CN208862747U (en) A kind of holding circuit of airborne power supply modules

Legal Events

Date Code Title Description
GR01 Patent grant
C14 Grant of patent or utility model