CN104218535A - An active PFC over-current protection circuit - Google Patents
An active PFC over-current protection circuit Download PDFInfo
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- CN104218535A CN104218535A CN201310214110.3A CN201310214110A CN104218535A CN 104218535 A CN104218535 A CN 104218535A CN 201310214110 A CN201310214110 A CN 201310214110A CN 104218535 A CN104218535 A CN 104218535A
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Abstract
The invention provides an active PFC over-current protection circuit, which detects both the current flowing through a power device and the current of a DC loop. Since the over-current in the power device is an instantaneous value, by means of detecting the current flowing through the power device, the PWM pulse which drives the on-off state of the power device is stopped in time from being outputted if it is detected that an over-current is occurring in the current in the power device. The interruption port, through which the current detected from the power device is fed back to MCU, can timely protect the power device from being damaged by the over-current because of its very fast response speed. By detecting a first voltage signal corresponding to the total current in a rectifying loop, and feeding back the detected first voltage signal to the A/D port of MCU, the PWM pulse is stopped from being outputted to the grid electrode of the power device if an over-current is occurring. If there is no over-current, the pulse width or duty cycle of the PWM pulse is adjusted in a closed-loop feedback manner based on the magnitude of the first voltage signal in order to enhance the effect of power factor compensation.
Description
Technical field
The present invention relates to power factor correction technology field, particularly the active PFC circuit overcurrent protection of one.
Background technology
Along with providing of commercial production levels and living standards of the people; the non-linear electrical equipment of a large amount of use creates increasing harmonic wave in electrical network; not only increase the loss of mains supply, affect the normal operation of electric network protection device, and reduce the power factor of power consumption equipment.
Transducer air conditioning just belongs to non-linear electrical equipment, therefore, in order to harmonic inhabitation generation and power factor is provided, in transducer air conditioning, introduce power factor correction (PFC, Power Factor Correction) technology.
The basic ideas of PFC are exactly that input current waveform is tending towards sinusoidal wave as far as possible and reduces with input voltage phase difference.
At present, PFC technology can be divided into PPFC (Passive Power Factor Correction) (PPFC) and Active Power Factor Correction (APFC).
PPFC mainly uses inductance and electric capacity etc. to form filter, the waveform of this filter adjustment input current and phase deviation.The advantage of PPFC is that circuit is fairly simple, cost is low, electromagnetic interference is few, working stability.
APFC mainly controls the make-and-break time of power switch component to adjust input current waveform and phase deviation thereof.The advantage of APFC is the harmonic components that improve power factor He reduce electric current.
The current world is all advocating energy savings, therefore also becomes the research emphasis of energy savings in convertible frequency air-conditioner.In order to reach the requirement of country's " 3C " forcible authentication, current harmonics suppression becomes the problem that convertible frequency air-conditioner producer must solve; Because traditional passive PFC harmonic inhabitation mode cannot solve the national high-energy-efficiency variable-frequency air-conditioning products advocated, so active PFC day by day becomes the mainstream scheme in convertible frequency air-conditioner industry.
The circumstance complication used due to convertible frequency air-conditioner is various, badness is more (as being struck by lightning, stopping in power supply wink, the power supply sudden turn of events, abnormity of power supply etc.); Also there is the features such as operate power is wide, frequency is high, the fluctuation of load is large simultaneously.Therefore, very high requirement is proposed to the reliability design of active PFC, wherein the Focal point and difficult point studied especially of the protection of overcurrent.A kind of safer reliable circuit overcurrent protection how is provided to be those skilled in the art's technical issues that need to address.
Summary of the invention
The technical problem to be solved in the present invention is to provide a kind of active PFC current foldback circuit, can saferly when pfc circuit exists overcurrent reliably protect.
The invention provides the circuit overcurrent protection of a kind of active PFC, comprising: the first current sample module, the second current sample module and MCU;
Described first current sample module, for gathering the first current signal in DC power supply circuit, is undertaken described first current signal being converted to the A/D mouth that the first corresponding voltage signal sends to described MCU;
Described second current sample module, for gathering the second current signal in active PFC circuit, power device flow through, when described second current signal exceedes the second threshold current of setting, sends interrupt signal to fracture in described MCU;
Described MCU, during for judging that described first voltage signal exceedes the first threshold voltage of setting, stops exporting pwm pulse; Or when in judging, fracture has an interrupt signal, stop exporting pwm pulse to power device.
Preferably, described first current sample module comprises: the first current sampling resistor, the first voltage conversion unit;
Described first current sampling resistor is connected between the output negative pole of rectifier bridge and DC power cathode;
Described first voltage conversion unit, after the current signal of described first current sampling resistor sampling is converted to voltage signal, sends to the A/D mouth of described MCU.
Preferably, described first voltage conversion unit comprises:
First operational amplifier, the second operational amplifier, the 3rd resistance, the 4th resistance, the 5th resistance, the 6th resistance, the 7th resistance and the 8th resistance;
The normal phase input end of described first operational amplifier is by the 8th grounding through resistance, and the normal phase input end of described first operational amplifier connects 0 ~ 24V power supply by the 7th resistance;
The inverting input of described first operational amplifier connects the output of described first operational amplifier;
The output of described first operational amplifier connects the normal phase input end of the second operational amplifier by the 5th resistance, the normal phase input end of described second operational amplifier is by the 6th grounding through resistance;
The output of described second operational amplifier is connected the output negative pole of rectifier bridge with the 3rd resistance by the 4th resistance of connecting successively;
The inverting input of described second operational amplifier connects the common port of the 3rd resistance and the 4th resistance.
Preferably, described first voltage conversion unit also comprises: the 3rd electric capacity, the 4th electric capacity, the 5th electric capacity, the 6th electric capacity, the 7th electric capacity;
The power supply of described first operational amplifier is by described 3rd capacity earth;
The power supply of described first operational amplifier is by described 5th capacity earth;
Described 3rd electric capacity is electrochemical capacitor, and described 5th electric capacity is polarity free capacitor;
The inverting input of described second operational amplifier is by described 4th capacity earth;
The normal phase input end of described first operational amplifier is by described 6th capacity earth;
Described 0 ~ 24V power supply is by described 7th capacity earth.
Preferably, described second current sample module comprises: the second current sampling resistor, the second voltage comparison unit;
Power device in described second current sampling resistor and active PFC circuit is in series, for detecting the current signal flowing through power device;
Described second voltage comparison unit, for the voltage be directly proportional to the voltage on described second current sampling resistor and predeterminated voltage are compared, when the voltage be directly proportional to the voltage on described second current sampling resistor exceedes predeterminated voltage, send interrupt signal to fracture in described MCU.
Preferably, described second voltage comparison unit comprises: the 11 resistance, the 13 resistance, the 14 resistance and the second comparator;
The normal phase input end of described second comparator is connected described DC power cathode by described 11 resistance with the second resistance;
The inverting input of described second comparator is by the 14 grounding through resistance, and described 14 resistance connects 0 ~ 24V power supply by described 13 resistance; Described 14 ohmically voltage is as described predeterminated voltage;
The output of described second comparator connects the middle fracture of MCU.
Preferably, described second voltage comparison unit also comprises: the 13 electric capacity, the 14 electric capacity, the 15 electric capacity, the 9th resistance, the tenth resistance and the first diode;
The two ends of described 13 electric capacity connect inverting input and the ground of described second comparator respectively;
Described 14 Capacitance parallel connection is at the two ends of described 14 resistance;
The two ends of described 15 electric capacity connect the VDD-to-VSS of the second comparator respectively;
Ten resistance, first diode, the nine resistance connection 0 ~ 24V power supply of inverting input by connecting successively of described second comparator;
The power supply of described second comparator is 0 ~ 24V.
Preferably, described MCU also when described first voltage signal exceedes the second threshold voltage of setting, cuts off to the current supply circuit of compressor for judging; When described first voltage signal exceedes the 3rd threshold voltage of setting, for power supply outside close chamber.
Preferably, described active PFC circuit comprises: radio-frequency rector, power device, fast recovery diode, electrochemical capacitor;
The output cathode of described rectifier bridge is connected DC power anode by the radio-frequency rector of series connection with fast recovery diode successively;
The two ends of described electrochemical capacitor connect described DC power anode and DC power cathode respectively;
Described radio-frequency rector is connected DC power cathode by the power device of connecting successively with the second sampling resistor with the common port of fast recovery diode.
Preferably, described active PFC circuit also comprises filter capacitor;
The two ends of described filter capacitor connect output cathode and the output negative pole of described rectifier bridge respectively.
Compared with prior art, the present invention has the following advantages:
The active PFC circuit overcurrent protection that the present embodiment provides, the electric current both detection power device flow through, detects again the electric current of DC loop.Like this, because the overcurrent on power device is instantaneous value, by the electric current that real-time detection power device flows through, when detecting that overcurrent appears in the electric current on power device, stop the pwm pulse exporting driving power devices switch state in time.Further, the current feedback on detection power device is middle fracture to MCU, because the response speed of middle fracture is very fast, therefore, can protect power device in time, in order to avoid power device damages because of overcurrent.Simultaneously, by the first voltage signal that the total current on detection commutating circuit is corresponding, first voltage signal is fed back to the A/D mouth of MCU, when there is overcurrent, stop the pwm pulse exporting to power device grid, when not there is overcurrent, can the pulse duration (or duty ratio) of closed loop feedback adjustment pwm pulse be carried out according to the size of the first voltage signal thus the effect of power factor compensation be got a promotion.
Accompanying drawing explanation
Fig. 1 is active PFC current foldback circuit embodiment one schematic diagram provided by the invention;
Fig. 2 is the first current sample module diagram provided by the invention;
Fig. 3 is the second current sample module diagram provided by the invention;
Fig. 4 is the circuit overcurrent protection figure of active PFC provided by the invention.
Embodiment
For enabling above-mentioned purpose of the present invention, feature and advantage become apparent more, are described in detail the specific embodiment of the present invention below in conjunction with accompanying drawing.
See Fig. 1, this figure is active PFC current foldback circuit embodiment one schematic diagram provided by the invention.
First, understand better to enable those skilled in the art and implement the technical scheme of the embodiment of the present invention, first introducing the operation principle of active PFC circuit below.
Active PFC circuit can be applied in the variable frequency control of air-conditioning, refrigerator, washing machine, fan electromotor etc., and scheme provided by the invention does not limit to its concrete application scenarios.
The active PFC circuit that the present embodiment provides comprises: radio-frequency rector L, power device Q, fast recovery diode D, electrochemical capacitor C2;
The output cathode of described rectifier bridge DB is connected DC power anode DC+ by the radio-frequency rector L of series connection with fast recovery diode C2 successively;
The two ends of described electrochemical capacitor C2 connect described DC power anode DC+ and DC power cathode DC-respectively;
Described radio-frequency rector L is connected DC power cathode DC-by the power device Q connected successively with the second sampling resistor R2 with the common port of fast recovery diode D.
The operation principle of active PFC circuit is:
When after power device Q conducting, direct voltage is added in radio-frequency rector L both sides, and L produces instantaneous large-current; This electric current flows into power device Q from the output cathode of rectifier bridge DB, then flow back into DC power cathode DC-.
When power device Q ends, the positive voltage of inducting that radio-frequency rector L produces makes electric current by fast recovery diode D, flows to electrochemical capacitor C2 and charges to it; Because the one-way conduction characteristic of fast recovery diode D, the voltage of C2 can not be added on the collector electrode of power device Q, and the grid of power device Q is connected with its power device drive circuit 2; Power device drive circuit 2 drives conducting and the disconnection of Q for exporting pwm pulse; When adopting the pwm pulse of high carrier frequency to make the frequent turn-on and turn-off of Q, direct current fails to be convened for lack of a quorum and to be pulled up and by L, D constantly to C2 charging, thus plays power factor compensation and promote the effect of direct voltage.
It should be noted that, direct voltage refers to the voltage between DC+ and DC-.
The circuit overcurrent protection of the active PFC that the present embodiment provides, comprising: the first current sample module 3, second current sample module 4 and MCU5;
Described first current sample module 3, for gathering the first current signal in DC power supply circuit, is undertaken described first current signal being converted to the A/D mouth that the first corresponding voltage signal sends to described MCU5;
Described second current sample module 4, for gathering the second current signal in active PFC circuit, power device flow through, when described second current signal exceedes the second threshold current of setting, sends interrupt signal to fracture in described MCU5;
Described MCU5, during for judging that described first voltage signal exceedes the first threshold voltage of setting, stops exporting pwm pulse; Or when in judging, fracture has an interrupt signal, stop exporting pwm pulse to power device.
The active PFC circuit overcurrent protection that the present embodiment provides, the electric current both detection power device Q flow through, detects again the electric current of DC loop.Like this, because the overcurrent on Q is instantaneous value, by detecting the electric current that Q flows through in real time, when detecting that overcurrent appears in the electric current on Q, stop in time exporting the pwm pulse driving Q switching state.Further, detecting current feedback on Q is middle fracture to MCU, because the response speed of middle fracture is very fast, therefore, can protect Q in time, in order to avoid Q damages because of overcurrent.Simultaneously, by the first voltage signal that the total current on detection commutating circuit is corresponding, first voltage signal is fed back to the A/D mouth of MCU, when there is overcurrent, stop the pwm pulse exporting to Q grid, when not there is overcurrent, can the pulse duration (or duty ratio) of closed loop feedback adjustment pwm pulse be carried out according to the size of the first voltage signal thus the effect of power factor compensation be got a promotion.
It should be noted that, if only detect the electric current that Q flows through, although overcurrent protection can be carried out to power device in real time.But owing to not detecting the total current of commutating circuit, therefore cannot compensate the superfluous overcurrent brought to active PFC and protect, and the pwm pulse width that cannot carry out closed loop feedback according to the instantaneous value of total current compensates process.
It should be noted that, if only have detected the total current of commutating circuit, the shortcoming only detecting the electric current on Q and bring can be made up, but power device cannot be protected in real time.This is because the overcurrent flowing through power device is instantaneous value, although also can be reflected on the sampling resistor of the total current of commutating circuit, the feedback of the way circuit of commutating circuit is the A/D mouth of MCU, is not middle fracture.Because the response processing speed of software is comparatively slow, therefore can cause overcurrent protection not in time, may also not have enough time to protect, power device be damaged.
Therefore; the circuit overcurrent protection that the embodiment of the present invention provides; electric current respectively on detection Q and the way circuit of commutating circuit; the instantaneous current value on Q can be detected so in time; and protected by fracture in MCU; carry out the fast response time protected like this, thus the impaired risk of Q can be reduced.
It should be noted that, the first current sampling resistor R1 in Fig. 1 belongs to the first current sample module 3; Second current sampling resistor R2 belongs to the second current sample module 4.
Described first current sampling resistor R1 is connected between the output negative pole of rectifier bridge DB and DC power cathode DC-;
Power device Q in described second current sampling resistor R2 and active PFC circuit is in series.
It should be noted that, described active PFC circuit also comprises filter capacitor C1;
The two ends of described filter capacitor C1 connect output cathode and the output negative pole of described rectifier bridge DB respectively.
The effect of this filter capacitor C1 is that protection rectifier bridge DB is not by impact failures such as thunderbolt, power-supply fluctuations; Have filtering EMC noise simultaneously concurrently, reduce the interference to power transmission electric network.
See Fig. 2, this figure is the first current sample module diagram provided by the invention.
The first current sample module 3 that the present embodiment provides comprises: the first current sampling resistor R1, the first voltage conversion unit 31;
Described first current sampling resistor R1 is connected between the output negative pole of rectifier bridge and DC power cathode;
Described first voltage conversion unit 31, after the current signal for being sampled by described first current sampling resistor R1 is converted to voltage signal, sends to the A/D mouth of described MCU5.
See Fig. 3, this figure is the second current sample module diagram provided by the invention.
The second current sample module that the present embodiment provides comprises: the second current sampling resistor R2, the second voltage comparison unit 41;
Power device in described second current sampling resistor R2 and active PFC circuit is in series, for detecting the current signal flowing through power device Q;
Described second voltage comparison unit 41, for the voltage be directly proportional to the voltage on described second current sampling resistor R2 and predeterminated voltage are compared, when the voltage be directly proportional to the voltage on described second current sampling resistor R2 exceedes predeterminated voltage, send interrupt signal to fracture in described MCU5.
A kind of specific implementation of the circuit overcurrent protection of the active PFC that the embodiment of the present invention provides is introduced in detail below in conjunction with accompanying drawing.
It should be noted that, the power supply in the present invention can be the power supply of 0 ~ 24V, can preferred+5V during concrete condition, and some application scenario can preferred+15V.The voltage of the concrete occasion had below can be distinguished to some extent, is not limited to the magnitude of voltage specifically enumerated.
See Fig. 4, this figure is the circuit overcurrent protection figure of active PFC provided by the invention.
Described first voltage conversion unit 31 comprises:
First operational amplifier IC1, the second operational amplifier IC2, the 3rd resistance R3, the 4th resistance R4, the 5th resistance R5, the 6th resistance R6, the 7th resistance R7 and the 8th resistance R8;
The normal phase input end of described first operational amplifier IC1 is by the 8th resistance R8 ground connection, and the normal phase input end of described first operational amplifier IC1 connects+5V power supply by the 7th resistance R7;
The inverting input of described first operational amplifier IC1 connects the output of described first operational amplifier IC1;
The output of described first operational amplifier IC1 connects the normal phase input end of the second operational amplifier IC2 by the 5th resistance R5, the normal phase input end of described second operational amplifier IC2 is by the 6th resistance R6 ground connection;
The output of described second operational amplifier IC2 is connected the output negative pole of rectifier bridge DB with the 3rd resistance R3 by the 4th resistance R4 connected successively;
The inverting input of described second operational amplifier IC2 connects the common port of the 3rd resistance R3 and the 4th resistance R4.
It should be noted that, IC1 is voltage follower herein, and IC2 is amplifier, and the advantage of design like this to improve the stability of hardware-in-the-loop.
It should be noted that, the first voltage conversion unit 31 sends to the A/D mouth of MCU after the first current sampling signal gathered is converted to the voltage signal of 0 ~ 5V.
It should be noted that, the reference voltage of the normal phase input end of IC1 is the voltage on R8, R7 and R8 series connection carries out dividing potential drop to 5V voltage.
The 1 pin voltage of required voltage V1(IC1 is obtained) by R7, R8, IC1 design voltage follower, the 5 pin voltages of target reference voltage V2(IC2 of IC2 are obtained again by the design of R5, R6 dividing potential drop), current sampling signal conversion zoomed into finally by the formula scales of R3, R4, R1, V2 the A/D voltage signal that IC2 the 7th pin exports.
Described second voltage comparison unit 41 comprises: the 11 resistance R11, the 13 resistance R13, the 14 resistance R14 and the second comparator IC3;
The normal phase input end of described second comparator IC3 is connected described DC power cathode DC-by described 11 resistance R11 with the second resistance R2;
The inverting input of described second comparator IC3 is by the 14 resistance R14 ground connection, and described 14 resistance R14 connects 5V power supply by described 13 resistance R13; Voltage on described 14 resistance R14 is as described predeterminated voltage;
The output of described second comparator IC3 connects the middle fracture of MCU5.
It should be noted that, R13 and R14 series connection carries out dividing potential drop as divider resistance to 5V, using the reference voltage of the voltage on R14 as the inverting input of IC3, i.e. described predeterminated voltage after dividing potential drop.
The voltage that second sampled current signals produces carries out dividing potential drop by R2 and R11, the normal phase input end of the voltage input IC3 after dividing potential drop.
When the voltage of IC3 normal phase input end is higher than voltage on R14, transmission overturns by the output signal of IC3, and such energizing signal is input to the middle fracture of MCU5.MCU5 carries out corresponding overcurrent protection.
It should be noted that, in order to improve the antijamming capability of this circuit overcurrent protection, the present invention have also been devised filter circuit.Continue composition graphs 4 below to describe in detail.
Described second voltage comparison unit 41 also comprises: the 13 electric capacity C13, the 14 electric capacity C14, the 15 electric capacity C15, the 9th resistance R9, the tenth resistance R10 and the first diode D1;
The two ends of described 13 electric capacity C13 connect inverting input and the ground of described second comparator IC3 respectively;
Described 14 electric capacity C14 is connected in parallel on the two ends of described 14 resistance R14;
The two ends of described 15 electric capacity C15 connect the VDD-to-VSS of the second comparator IC3 respectively;
The inverting input of described second comparator IC3 connects+5V power supply by the tenth resistance R10, the first diode D1 that connect successively, the 9th resistance R9;
The power supply of described second comparator IC3 is+15V.
The effect of C13 is the noise in order to filtering second sampled current signals;
The effect of C14 is in order to the noise in the reference voltage of the inverting input of filtering IC3;
The effect of C15 is the level and smooth and filtering in order to make between the power supply+15V of IC3 and ground G.
Described first voltage conversion unit also comprises: the 3rd electric capacity C3, the 4th electric capacity C4, the 5th electric capacity C5, the 6th electric capacity C6, the 7th electric capacity C7;
The power supply of described first operational amplifier IC1 is by described 3rd electric capacity C3 ground connection;
The power supply of described first operational amplifier IC1 is by described 5th electric capacity C5 ground connection;
C3 is electrochemical capacitor; Mainly play smoothing effect, have filter action concurrently;
C5 is polarity free capacitor, strobes;
15V holds ground connection by C3 and C5 these two, and supply voltage stability improves, and noise jamming reduces.
The inverting input of described second operational amplifier IC2 is by described 4th electric capacity C4 ground connection;
The normal phase input end of described first operational amplifier IC1 is by described 6th electric capacity C6 ground connection;
Described+5V power supply is by described 7th electric capacity C7 ground connection.
The effect of C4 is in order to the noise in the input signal of filtering IC2 inverting input (the 6th pin);
The effect of C6 is in order to the noise in the input signal of filtering IC1 normal phase input end (the 3rd pin);
C7 is electrochemical capacitor; Mainly play the smoothing effect of 5V power supply, have filter function concurrently.
D1 and R10 Combination Design is the stability in order to improve comparator.
It should be noted that, in the circuit overcurrent protection that the above embodiment of the present invention provides, described MCU also when described first voltage signal exceedes the second threshold voltage of setting, cuts off to the current supply circuit of compressor for judging; When described first voltage signal exceedes the 3rd threshold voltage of setting, for closing all power supplies.
Be understandable that, because the feedback end detecting DC loop total current in the embodiment of the present invention is the A/D mouth of MCU, therefore, MCU implements the control strategy of different stage by the size of the voltage signal judging A/D.
Such as, three protection levels are set.Described first threshold voltage corresponding is respectively 3.8V, and the second threshold voltage is 4.2V, and the 3rd threshold voltage is 4.5V etc.It should be noted that, these three threshold voltages can free setting is different according to actual needs numerical value, only illustrates, do not limit to concrete numerical value at this.
When the first voltage signal is less than 3.8V, the pulse duration of MCU only control PWM, does not stop exporting pwm pulse.The power factor of whole air-conditioning system can be improved like this.
When the first voltage signal be more than or equal to 3.8V be less than 4.2V time, MCU stop export pwm pulse;
When the first voltage signal be more than or equal to 4.2V be less than 4.5V time, MCU stops exporting pwm pulse, and it is out of service to control compressor; The safety of whole air-conditioning system can be ensured like this.
When the first voltage signal is more than or equal to 4.5V, the power supply that MCU controls outside air conditioning chamber stops.
It should be noted that; for the various protections that the detection of commutating circuit total current is implemented in the above embodiment of the present invention; can also by setting up in AC power supplies loop the total current that Current Transmit detects AC power supplies loop; and then realize various protection; principle is identical with the principle of the total current detecting commutating circuit, does not repeat them here.
The above is only preferred embodiment of the present invention, not does any pro forma restriction to the present invention.Although the present invention discloses as above with preferred embodiment, but and be not used to limit the present invention.Any those of ordinary skill in the art, do not departing under technical solution of the present invention ambit, the Method and Technology content of above-mentioned announcement all can be utilized to make many possible variations and modification to technical solution of the present invention, or be revised as the Equivalent embodiments of equivalent variations.Therefore, every content not departing from technical solution of the present invention, according to technical spirit of the present invention to any simple modification made for any of the above embodiments, equivalent variations and modification, all still belongs in the scope of technical solution of the present invention protection.
Claims (10)
1. a circuit overcurrent protection of active PFC, is characterized in that, comprising: the first current sample module, the second current sample module and MCU;
Described first current sample module, for gathering the first current signal in DC power supply circuit, is undertaken described first current signal being converted to the A/D mouth that the first corresponding voltage signal sends to described MCU;
Described second current sample module, for gathering the second current signal in active PFC circuit, power device flow through, when described second current signal exceedes the second threshold current of setting, sends interrupt signal to fracture in described MCU;
Described MCU, during for judging that described first voltage signal exceedes the first threshold voltage of setting, stops exporting pwm pulse; Or when in judging, fracture has an interrupt signal, stop exporting pwm pulse to power device.
2. the circuit overcurrent protection of active PFC according to claim 1, is characterized in that, described first current sample module comprises: the first current sampling resistor, the first voltage conversion unit;
Described first current sampling resistor is connected between the output negative pole of rectifier bridge and DC power cathode;
Described first voltage conversion unit, after the current signal of described first current sampling resistor sampling is converted to voltage signal, sends to the A/D mouth of described MCU.
3. the circuit overcurrent protection of active PFC according to claim 2, is characterized in that, described first voltage conversion unit comprises:
First operational amplifier, the second operational amplifier, the 3rd resistance, the 4th resistance, the 5th resistance, the 6th resistance, the 7th resistance and the 8th resistance;
The normal phase input end of described first operational amplifier is by the 8th grounding through resistance, and the normal phase input end of described first operational amplifier connects 0 ~ 24V power supply by the 7th resistance;
The inverting input of described first operational amplifier connects the output of described first operational amplifier;
The output of described first operational amplifier connects the normal phase input end of the second operational amplifier by the 5th resistance, the normal phase input end of described second operational amplifier is by the 6th grounding through resistance;
The output of described second operational amplifier is connected the output negative pole of rectifier bridge with the 3rd resistance by the 4th resistance of connecting successively;
The inverting input of described second operational amplifier connects the common port of the 3rd resistance and the 4th resistance.
4. the circuit overcurrent protection of active PFC according to claim 3, is characterized in that, described first voltage conversion unit also comprises: the 3rd electric capacity, the 4th electric capacity, the 5th electric capacity, the 6th electric capacity, the 7th electric capacity;
The power supply of described first operational amplifier is by described 3rd capacity earth;
The power supply of described first operational amplifier is by described 5th capacity earth;
Described 3rd electric capacity is electrochemical capacitor, and described 5th electric capacity is polarity free capacitor;
The inverting input of described second operational amplifier is by described 4th capacity earth;
The normal phase input end of described first operational amplifier is by described 6th capacity earth;
Described 0 ~ 24V power supply is by described 7th capacity earth.
5. the circuit overcurrent protection of active PFC according to claim 1, is characterized in that, described second current sample module comprises: the second current sampling resistor, the second voltage comparison unit;
Power device in described second current sampling resistor and active PFC circuit is in series, for detecting the current signal flowing through power device;
Described second voltage comparison unit, for the voltage be directly proportional to the voltage on described second current sampling resistor and predeterminated voltage are compared, when the voltage be directly proportional to the voltage on described second current sampling resistor exceedes predeterminated voltage, send interrupt signal to fracture in described MCU.
6. the circuit overcurrent protection of active PFC according to claim 5, is characterized in that, described second voltage comparison unit comprises: the 11 resistance, the 13 resistance, the 14 resistance and the second comparator;
The normal phase input end of described second comparator is connected described DC power cathode by described 11 resistance with the second resistance;
The inverting input of described second comparator is by the 14 grounding through resistance, and described 14 resistance connects 0 ~ 24V power supply by described 13 resistance; Described 14 ohmically voltage is as described predeterminated voltage;
The output of described second comparator connects the middle fracture of MCU.
7. the circuit overcurrent protection of active PFC according to claim 6, is characterized in that, described second voltage comparison unit also comprises: the 13 electric capacity, the 14 electric capacity, the 15 electric capacity, the 9th resistance, the tenth resistance and the first diode;
The two ends of described 13 electric capacity connect inverting input and the ground of described second comparator respectively;
Described 14 Capacitance parallel connection is at the two ends of described 14 resistance;
The two ends of described 15 electric capacity connect the VDD-to-VSS of the second comparator respectively;
Ten resistance, first diode, the nine resistance connection 0 ~ 24V power supply of inverting input by connecting successively of described second comparator;
The power supply of described second comparator is 0 ~ 24V.
8. active PFC circuit overcurrent protection according to claim 1, is characterized in that, described MCU also when described first voltage signal exceedes the second threshold voltage of setting, cuts off to the current supply circuit of compressor for judging; When described first voltage signal exceedes the 3rd threshold voltage of setting, for power supply outside close chamber.
9. the circuit overcurrent protection of the active PFC according to any one of claim 1-8, is characterized in that, described active PFC circuit comprises: radio-frequency rector, power device, fast recovery diode, electrochemical capacitor;
The output cathode of described rectifier bridge is connected DC power anode by the radio-frequency rector of series connection with fast recovery diode successively;
The two ends of described electrochemical capacitor connect described DC power anode and DC power cathode respectively;
Described radio-frequency rector is connected DC power cathode by the power device of connecting successively with the second sampling resistor with the common port of fast recovery diode.
10. the circuit overcurrent protection of active PFC according to claim 9, is characterized in that, described active PFC circuit also comprises filter capacitor;
The two ends of described filter capacitor connect output cathode and the output negative pole of described rectifier bridge respectively.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310214110.3A CN104218535B (en) | 2013-05-31 | 2013-05-31 | A kind of active PFC overcurrent protection circuits |
Applications Claiming Priority (1)
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| US20160181866A1 (en) * | 2013-08-14 | 2016-06-23 | Cockerill Maintenance & Ingenierie S.A. | Remote protection and switching device for electrical systems |
| CN112290506A (en) * | 2020-09-29 | 2021-01-29 | 四川虹美智能科技有限公司 | Surge protection device and method |
| CN113746066A (en) * | 2020-05-29 | 2021-12-03 | 比亚迪股份有限公司 | Current converter overcurrent protection method and circuit and current converter controller |
| CN114006524A (en) * | 2021-11-05 | 2022-02-01 | 上海儒竞智控技术有限公司 | Method, medium and control circuit for realizing over-current suppression and Boost type PFC control system |
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| CN114006524A (en) * | 2021-11-05 | 2022-02-01 | 上海儒竞智控技术有限公司 | Method, medium and control circuit for realizing over-current suppression and Boost type PFC control system |
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