CN109038476A - A kind of current foldback circuit and controller - Google Patents
A kind of current foldback circuit and controller Download PDFInfo
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- CN109038476A CN109038476A CN201810894505.5A CN201810894505A CN109038476A CN 109038476 A CN109038476 A CN 109038476A CN 201810894505 A CN201810894505 A CN 201810894505A CN 109038476 A CN109038476 A CN 109038476A
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- 238000005070 sampling Methods 0.000 claims abstract description 85
- 238000001514 detection method Methods 0.000 claims abstract description 53
- 238000012512 characterization method Methods 0.000 claims abstract description 4
- 230000005611 electricity Effects 0.000 claims description 8
- 238000000034 method Methods 0.000 description 4
- 239000000243 solution Substances 0.000 description 4
- 238000010586 diagram Methods 0.000 description 2
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- 238000002347 injection Methods 0.000 description 2
- 239000007924 injection Substances 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 230000001681 protective effect Effects 0.000 description 2
- 239000003507 refrigerant Substances 0.000 description 2
- 230000004044 response Effects 0.000 description 2
- 230000009471 action Effects 0.000 description 1
- 238000004378 air conditioning Methods 0.000 description 1
- 230000003321 amplification Effects 0.000 description 1
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Classifications
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/08—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess current
- H02H3/081—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess current and depending on the direction
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/08—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess current
- H02H3/083—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess current for three-phase systems
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/08—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for dynamo-electric motors
- H02H7/085—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for dynamo-electric motors against excessive load
- H02H7/0854—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for dynamo-electric motors against excessive load responsive to rate of change of current, couple or speed, e.g. anti-kickback protection
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Abstract
The present invention provides a kind of current foldback circuit and controller, which includes sampling unit, direction detection amplifier unit, protection signal output unit；Sampling unit samples the electric current of sampling circuit, and exports the sampled signal for characterizing the electric current of the sampling circuit；It includes operational amplifier that direction, which detects amplifier unit; sampled signal is input to the first input end of operational amplifier; second input end grounding of operational amplifier; operational amplifier generates the detection signal of the current direction in characterization sampling circuit according to sampled signal, and exports to protection signal output unit；It protects signal output unit to generate protection signal according to detection signal, and exports to control circuit, control circuit controls the electric current in the sampling circuit according to protection signal.The present invention detects the detection that amplifier unit realizes electric current in sampling circuit by direction, then the overcurrent protection of negative current is realized by protection signal output unit.
Description
Technical field
The present invention relates to circuit protection technical field more particularly to a kind of current foldback circuits and controller.
Background technique
In electronic product, electric current is excessive in order to prevent causes device failure and causes product failure, and overcurrent protection is arranged
Circuit.In some control systems, not only in will appear forward current, there is also reverse current；Therefore, can not only exist just
To overcurrent, can also there be reverse overcurrent.
Summary of the invention
In view of this, effectively solving the embodiment of the invention provides a kind of current foldback circuit and controller because of negative sense electricity
The problem of flowing through big caused fault.Specific technical solution is as follows:
A kind of current foldback circuit, including sampling unit, direction detection amplifier unit, protection signal output unit；
The sampling unit is at least partially disposed in sampling circuit, for sampling the electric current of the sampling circuit, and is exported
Characterize the sampled signal of the electric current of the sampling circuit；Size of current in the sampling circuit is controlled by control circuit；
The direction detection amplifier unit includes operational amplifier, and the sampled signal is input to the operational amplifier
First input end, the second input end grounding of the operational amplifier, the operational amplifier are generated according to the sampled signal
The detection signal of the current direction in the sampling circuit is characterized, and is exported to the protection signal output unit；
The protection signal output unit generates protection signal according to the detection signal, and exports to the control electricity
Road, the control circuit control the electric current in the sampling circuit according to the protection signal.
The embodiment of the invention also provides a kind of controllers, for controlling compressor, including driving circuit and MCU control electricity
Road, above-mentioned current foldback circuit, the current foldback circuit output protection signal to the driving circuit or MCU control electricity
Road.
A kind of current foldback circuit provided in an embodiment of the present invention detects amplifier unit by direction and detects sampling circuit
Middle sense of current, the current direction is different, and the detection signal magnitude range that direction detects the output of amplifier unit is different, then passes through
Protect signal output unit according to the detection signal output protection signal to control circuit, control circuit is believed according to the protection
Number, protection act is executed, prevents whole system from overcurrent fault occurs.
A kind of controller plc provided in an embodiment of the present invention realizes negative current mistake by above-mentioned current foldback circuit
The protection of stream, effectively increases circuit stability, guarantees the operational safety of compressor.
Detailed description of the invention
In order to more clearly explain the embodiment of the invention or the technical proposal in the existing technology, to embodiment or will show below
There is attached drawing needed in technical description to be briefly described, it should be apparent that, the accompanying drawings in the following description is only this
The embodiment of invention for those of ordinary skill in the art without creative efforts, can also basis
Disclosed attached drawing obtains other attached drawings.
Fig. 1 is the current foldback circuit structural block diagram that one embodiment of the invention provides；
Fig. 2 be another embodiment of the present invention provides current foldback circuit structure chart；
Fig. 3 be another embodiment of the present invention provides controller architecture block diagram；
Fig. 4 be another embodiment of the present invention provides controller circuit structure figure.
Specific embodiment
Following will be combined with the drawings in the embodiments of the present invention, and technical solution in the embodiment of the present invention carries out clear, complete
Site preparation description, it is clear that described embodiments are only a part of the embodiments of the present invention, instead of all the embodiments.It is based on
Embodiment in the present invention, it is obtained by those of ordinary skill in the art without making creative efforts every other
Embodiment shall fall within the protection scope of the present invention.
In circuit, overcurrent protection is a kind of common function, and when electric current only has a kind of direction, (we claim the electric current
Flow direction is forward direction), it is only necessary to forward current current foldback circuit, which is arranged, can be realized overcurrent protection.But in many circuit loops
In, for example the main control loop of compressor, current direction be simultaneously not fixed, that is to say, that existing forward current, and have negative current
(electric current contrary with forward current) is therefore only arranged forward current current foldback circuit and is not enough to realize negative sense overcurrent
Protection.Based on this, the embodiment of the invention provides a kind of current foldback circuits, can be realized the overcurrent protection of negative current.
A kind of current foldback circuit disclosed by the embodiments of the present invention is connected with control circuit, and control circuit controls sampling circuit
In size of current, sampling circuit be by the circuit of overcurrent protection, current foldback circuit 1 is according to size of current in sampling circuit
Output protection signal Vp, until control circuit, after control circuit receives protection signal Vp, executes the electric current in control sampling circuit
Reduce or stop a series of one of overcurrent protection movements such as itself work or various motion, to play circuit protection function
Energy.Specifically, as shown in Figure 1, the current foldback circuit includes sampling unit 11, direction detection amplifier unit 12, protection signal
Output unit 13；
The sampling unit 11 is at least partially disposed in sampling circuit, for sampling the electric current of the sampling circuit, and it is defeated
The sampled signal Vs of the electric current of the sampling circuit is characterized out；Size of current in the sampling circuit is controlled by control circuit；
The direction detection amplifier unit 12 includes operational amplifier, and the sampled signal Vs is input to the operation amplifier
The first input end of device, the second input end grounding of the operational amplifier, the operational amplifier is according to the sampled signal
Vs generates the detection signal Vj for characterizing the current direction in the sampling circuit, and exports to the protection signal output unit
13；Current direction in the sampling circuit is different, and the detection signal Vj magnitude range is different；It should be noted that described
Second input end grounding of operational amplifier, which does not represent, to be coupled directly to ground, and can also be connected by resistance or other electronic devices
It is connected to ground.
The protection signal output unit 13 generates protection signal Vp according to the detection signal Vj, and exports to described
Control circuit, the control circuit control the electric current in the sampling circuit according to the protection signal Vp.
In the present embodiment, when the current direction difference in sampling circuit, the sampled signal of the output of sampling unit 11
Vs is of different sizes, and sampled signal Vs is of different sizes, and the size for detecting signal Vj is also different, and the direction sampled signal Vs is different
When, detection signal Vj magnitude range is different, for example, realizing that working as electric current in sampling circuit is forward direction, then examines by operational amplifier
Survey signal Vj size be (V1, V2]；When in sampling circuit electric current be negative sense when, detection signal Vj size be [0, V1)；Work as sampling
When size of current is 0 in circuit, detection signal Vj size is V1.Detection signal Vj is input to protection signal output unit 13, root
Generating protection signal Vp according to Vj can be for when Vj is more than or less than a certain a reference value, output protection signal Vp, Vp be can be
High level signal, the signal of normal work and overcurrent work, the present invention can be distinguished by being also possible to low level signal or other
It does not limit this.Control circuit can be central processing control circuit or switching circuit, such as MCU control circuit, CPU control
Circuit, buck circuit (buck circuit), boost circuit (boost circuit) or flyback circuit (circuit of reversed excitation) processed etc.
Deng.Control circuit receives to execute protection act after protection signal Vp, and protection act, which can be, reduces sampling circuit electric current, can also
To be control chip in closing control circuit, so that circuit is in intermittent work state or directly circuit is made to stop working
Deng.
In another specific embodiment, as shown in Fig. 2, sampling unit 11 includes sampling resistor Rs, biasing resistor Rc, divides
Piezoresistance Rf and bias voltage Vcc, the sampling resistor Rs is connected in the sampling circuit, for detecting in sampling circuit
Electric current Is in sampling circuit, not only will appear forward current Is1, but also will appear negative current Is2.The biasing resistor Rc and institute
It states divider resistance Rf to divide the voltage on the bias voltage and the sampling resistor, and regard partial pressure result as sampling
Signal Vs is input to the direction detection amplifier unit 12.In the present embodiment, analyzes for convenience, enable the one end sample circuit Rs
Ground connection, sampling resistor the Rs other end voltage Vs1=Is*Rs, sampled signal Vs=Vs1+ (Vcc-Vs1)/(Rc+Rf) * Rf, by this
Formula is it is found that Vs and Is direct proportionality, Is increase, and Vs increases, and wherein Is has direction.Therefore, the present embodiment is single by sampling
The electric current Is of the 11 sampling sampling circuit of member, and obtain characterizing the sampled signal Vs of the electric current Is of the sampling circuit, it inputs
Amplifier unit 12 is detected to direction.Certain sampling unit 11 also may include current transformer (CT), the side of current transformer
Windings in series is in sampling circuit.Therefore, sampling unit is at least partially disposed in sampling circuit.
Further, in the above-described embodiments, as shown in Fig. 2, in the operational amplifier U1 of direction detection amplifier unit 12,
The first input end is the positive input of the operational amplifier, and sampled signal Vs is input to the forward direction of operational amplifier U1
Input terminal, second input terminal are the reverse input end of the operational amplifier；The reverse input end passes through first resistor
R1 is grounded, and the output end of the operational amplifier is connected to by second resistance R2.In the present embodiment, operational amplifier U1's
Output end output detection signal Vj be analog quantity, and with sampled signal Vs also direct proportionality.Therefore, Vj is also that characterization is adopted
Another signal of sample loop current Is.It should be noted that in the present embodiment, the opamp-output signal of setting and input
The relationship of signal is in direct ratio, when sampled signal direction or it is of different sizes when, detection signal Vj it is also different, therefore detect signal Vj
The size of current in sampling circuit or direction can be characterized.
Further, in the above-described embodiments, as shown in Fig. 2, protection signal output unit 13 compares including negative current
Device U2, the negative current comparator compare the output end that end connects the operational amplifier, the negative current comparator base
Quasi- end connects reversed reference signal, when the negative current is greater than negative current threshold value, the reversed comparator output protection
Signal, the negative current threshold value are corresponding with the reversed reference signal.Let it be assumed, for the purpose of illustration, that negative current threshold value is
I2-, when the absolute value of negative current Is2 is greater than the absolute value of I2-, triggering reverse overcurrent protection.Specifically, working as | Is2 | > |
I2- | when, it is contemplated that the direction Is2 is negative, then Is2 < I2-, then (Vs2 corresponds to Is2 to Vs < Vs2, by bias voltage, biased electrical
Resistance, sampling resistor and divider resistance determine), then (Vj2 corresponds to Is2 to Vj < Vj2, is determined by the amplification factor of operational amplifier U1
It is fixed), at this point, it is Vj2 that reversed reference signal Vref2, which is arranged, in the present embodiment, reversed reference signal connect reversed comparator U2 just
To input terminal, therefore, as Vj < Vref2, reversed comparator output is the protection signal of high level, which is input to control
Circuit processed after control circuit receives the protection signal of high level, executes protection act.
Further, in order to while realizing that reverse overcurrent is protected, realize positive overcurrent protection, in the present embodiment
In, the protection signal output unit further includes forward current comparator, when forward current Is1 is greater than forward current threshold value,
Forward current comparator output protection signal.Specifically, the comparison end of forward current comparator can be directly connected to sampling letter
Number output end, the sampled signal Vs for receiving characterization electric current Is can be the ungrounded end of sampling resistor Rs in Fig. 2, can also be with
It is the common end of divider resistance Rf and Rc, equally, the comparison end of forward current comparator also may be coupled to direction detection amplifier
The output end of unit receives detection signal Vj, and forward current comparator reference end connects forward reference signal, adopts when described
When forward current is greater than forward current threshold value in sample circuit, the forward direction comparator output protection signal, the forward current threshold
Value is corresponding with the forward reference signal, i.e., forward reference signal is determined by forward current threshold value.Referring to saying for reversed comparator
It is bright, it is assumed that control circuit executes protection act after receiving high level, then setting, which is compared, holds as positive current comparator just
Input terminal, reference edge are that its reverse input end is input to the sampled signal that positive comparator compares end when forward current overcurrent
Greater than the forward reference signal of reference edge, then forward current comparator exports high level, which is input to control circuit,
After control circuit receives the protection signal after high level, protection act is executed.It should be noted that positive, direction input terminal
Setting only need with control circuit execute protection act logic meet, if control circuit is set as low level and executes guarantor
Shield acts, then the positive input and reverse input end of operational amplifier U1, reverse current comparator and forward current comparator
Corresponding change is made, the present invention is not specifically limited in this embodiment.
For the control system of motor, such as compressor, it will appear negative current in the process of running, therefore, only
Forward current current foldback circuit be it is inadequate, it is safe and reliable in order to guarantee, it is necessary to which that negative current overcurrent protection electricity is set
Road.Especially for air-heater convertible frequency air-conditioner, for the heating efficiency and inexpensive requirement for reaching extremely low temperature, selection exists
Additional air injection enthalpy-increasing function becomes the solution that many air-heater convertible frequency air-conditioners producer takes on the basis of domestic variable frequency air-conditioning, but
The refrigerant of vapour-liquid mixed state can cause mechanical shock to compressor rotor when air injection enthalpy-increasing, especially in liquid refrigerants ingredient
Impact is bigger when more, step-out, de- the problem of adjusting can be caused to the driving of compressor, compressor is in motor/power generation at this time
It is more frequent and serious to generate the phenomenon that positive/negative electric current is alternately produced for the alternate state of machine.
Based on above-mentioned current foldback circuit, the embodiment of the invention also provides a kind of controllers, for controlling compressor,
As shown in figure 3, including that driving circuit 2, MCU control circuit 3 and above-mentioned current foldback circuit 1, the current foldback circuit are defeated
Protection signal is to the driving circuit or MCU control circuit out, to realize overcurrent protection.Wherein, driving circuit 2 can be
The driving circuit for being used to drive compressor of discrete device composition, or IPM (intelligent power module) driving circuit.
Further, the electric current of controller provided in an embodiment of the present invention, the sampling circuit of the current foldback circuit is
The sum of described compressor three-phase current, the sampling unit of the current foldback circuit are placed in the compressor current total loop,
I.e. U/V/W three-phase current flows through the sampling unit after converging.Specifically, sampling unit includes that a single sampling resistor is (or multiple
Resistance is series-parallel), wherein the connection relationship of single sampling resistor Rs is as shown in figure 4, sampling unit 11 is examined by list sampling resistor Rs
It measures the electric current for flowing through compressor and exports the sampled signal Vs for characterizing the electric current, sampled signal Vs is input to direction detection fortune
The input terminal for putting unit 12, when the current direction that flows through compressor and it is of different sizes when, the range for detecting signal Vj is also different.Tool
Body, direction detects amplifier unit as shown in figure 4, including operational amplifier U1, by the parameter to operational amplifier U1 and instead
The setting of network is presented, so that direction detects the output A/D voltage signal (inspection in amplifier circuit 12 when the electric current of compressor is 0A
Survey signal Vj) it is V1；When the electric current of compressor is positive (as shown in Is1), direction detects the output A/D electricity in amplifier circuit 12
Pressure signal (detection signal Vj) changes between V1~V2；When the electric current of compressor is negative sense (as shown in Is2), direction detection fortune
The output A/D voltage signal (detection signal Vj) for putting back to road 12 changes between 0V~V1；Therefore, it can pass through detection signal Vj's
Range judges the current direction of compressor.Again by protecting signal output unit 13 to judge Vj, decide whether
Output protection signal Vp.Specifically, in the present embodiment, protection signal output unit 13 includes comparator U2, if flowing through pressure
The electric current of contracting machine is excessive (overcurrent), when protection threshold voltage more than comparator U2, comparator output signal reversion, and this reversion electricity
Ordinary mail number enters the Cin/Ocp overcurrent protection port in IPM driving circuit, after triggering IPM protection, the circuit meeting of IPM internal hardware
It cuts off six road IGBT driving signal certain time interval Ts while drags down Fo (fault output) output, this Fo signal is fed back to
MCU control circuit, then responded by MCU calculation process, stopped within certain time interval T six road IGBT PWM drive signal it is defeated
Out, to play the role of overcurrent protection, avoid compressor damage.
On that basi of the above embodiments, the protection signal output unit output protection signal of the current foldback circuit is to institute
The overcurrent protection port for stating IPM driving circuit, the PWM drive signal that six phases for cutting off the IPM driving circuit input.Into
One step, the direction detection amplifier unit of the current foldback circuit and/or the output end of protection signal output unit are also connected with
To the MCU control circuit, for cutting off the PWM drive signal of the IPM driving circuit or six phase input.This implementation
In example, overcurrent protection is realized except through IPM driving circuit, overcurrent protection is also realized by MCU control unit, is protected when receiving
After protecting signal, MCU control circuit stops the output of the PWM drive signal of six road IGBT, to play the second protective effect again.
In order to realize multiple protective, over-current protecting unit is set in the MCU control circuit, the over-current protecting unit connects
Detection signal is received, when overcurrent occurs, different protection acts is executed according to the detection signal magnitude, for example the overcurrent is protected
It protects unit and different protected modes is selected according to the protection signal of input or detection signal magnitude, such as when serious overcurrent, overcurrent
Protection location directly closes the driving of IGBT, and entire control system is out of service；When overcurrent is more serious, intermittence is closed
The driving of IGBT, to take into account the normal work of overcurrent protection and entire controller.
In above controller embodiment, the detection signal of direction detection amplifier unit output is analog signal and can characterize
The compressor current, compressor current are related with compressor drum position.Therefore, detection amplifier unit in direction, which is also able to achieve, turns
Sub- position detecting function.Based on this, the present invention also provides another embodiment, the direction of the current foldback circuit detects fortune
It puts unit output end and is connected to the MCU control circuit, the MCU control circuit receives the direction detection amplifier unit output
Detection signal, and the position of compressor drum is judged according to the detection signal magnitude, further according to the compressor drum
Position carries out six phase drive control of IPM.The present embodiment is not only able to achieve overcurrent protection, moreover it is possible to carry out IPM six according to rotor-position
Phase drive control.Specifically, detection signal is output to MCU control circuit, MCU control circuit carries out vector to the detection signal
Operation, changes the pulsewidth or frequency of PWM drive signal according to operation result, to realize being precisely controlled for six phase of IPM driving；Its
In, vector operation approach includes current error method or expansion electrification platen press etc. thoroughly.
Controller provided in an embodiment of the present invention has the advantage that
1) the compressor negative current overcurrent protection hardware-in-the-loop for devising quick response, when negative sense overcurrent generates,
Sampling unit 11, direction detection amplifier unit 12, the protection signal output comprising negative current comparator U2 can be passed through in time
Unit 13, IPM driving circuit 2, MCU control circuit 3, cut off IPM internal hardware and be cut off by MCU process control
The PWM drive signal of six phases input pacifies power device IPM and compressor by the quick response in hardware protection circuit in time
Stopping acts entirely.
2) MCU chip that overcurrent protection signal is fed back to software MCU control circuit is devised, makes MCU chip by setting
Protection system drive content, carry out normal action protection stopping processing.
It should be understood that the above embodiments are only used to illustrate the present invention and not limits technology described in the invention
Scheme, although this specification is referring to above-mentioned embodiment, the present invention has been described in detail, this field it is general
Lead to it will be appreciated by the skilled person that person of ordinary skill in the field still can modify to the present invention or equally replace
It changes, and all do not depart from the technical solution and its improvement of the spirit and scope of the present invention, should all cover and want in right of the invention
It asks in range.
Claims (10)
1. a kind of current foldback circuit, which is characterized in that including sampling unit, direction detection amplifier unit, protection signal output
Unit；
The sampling unit is at least partially disposed in sampling circuit, for sampling the electric current of the sampling circuit, and exports characterization
The sampled signal of the electric current of the sampling circuit；Size of current in the sampling circuit is controlled by control circuit；
The direction detection amplifier unit includes operational amplifier, and the sampled signal is input to the first of the operational amplifier
Input terminal, the second input end grounding of the operational amplifier, the operational amplifier are generated according to the sampled signal and are characterized
The detection signal of current direction in the sampling circuit, and export to the protection signal output unit；
The protection signal output unit generates protection signal according to the detection signal, and exports to the control circuit, institute
Control circuit is stated according to the electric current for protecting signal to control in the sampling circuit.
2. current foldback circuit according to claim 1, which is characterized in that the sampling unit include sampling resistor, partially
Resistance, divider resistance and bias voltage are set, the sampling resistor is connected in the sampling circuit, the biasing resistor and described
Divider resistance divides the voltage on the bias voltage and the sampling resistor, and partial pressure result is believed as sampling
Number, it is input to the direction detection amplifier unit.
3. current foldback circuit according to claim 1, which is characterized in that the first input end is the operation amplifier
The positive input of device, second input terminal are the reverse input end of the operational amplifier；The reverse input end passes through
First resistor is grounded, and the output end of the operational amplifier is connected to by second resistance.
4. current foldback circuit according to claim 1-3, which is characterized in that the protection signal output unit
Including negative current comparator, the negative current comparator compares the output end that end connects the operational amplifier, described negative
Reversed reference signal is connected to current comparator reference edge, it is described reversed when the negative current is greater than negative current threshold value
Comparator output protection signal, the negative current threshold value are corresponding with the reversed reference signal.
5. current foldback circuit according to claim 4, which is characterized in that the protection signal output unit further includes just
To current comparator, the forward current comparator compares end and receives the sampled signal or the detection signal, it is described just
Forward reference signal is connected to current comparator reference edge, when forward current is greater than forward current threshold value in the sampling circuit
When, the forward direction comparator output protection signal, the forward current threshold value is corresponding with the forward reference signal.
6. a kind of controller, for controlling compressor, including driving circuit and MCU control circuit, which is characterized in that further include as
The described in any item current foldback circuits of claim 1-5, the current foldback circuit output protection signal to the driving electricity
Road or MCU control circuit.
7. controller according to claim 6, which is characterized in that the electric current of the sampling circuit of the current foldback circuit is
The sum of described compressor three-phase current, the sampling unit of the current foldback circuit are placed in the compressor current total loop.
8. controller according to claim 7, which is characterized in that the driving circuit is IPM driving circuit, the overcurrent
It protects the protection signal output unit output protection signal of circuit to the overcurrent protection port of the IPM driving circuit, works as overcurrent
When, cut off the PWM drive signal of the six phases input of the IPM driving circuit.
9. controller according to claim 8, which is characterized in that the MCU control circuit includes that overcurrent protection selection is single
Member, the overcurrent protection selecting unit are connected to the direction detection amplifier unit and receive the detection signal, when overcurrent, institute
It states overcurrent protection selecting unit and different protected modes is selected according to the detection signal magnitude.
10. according to the described in any item controllers of claim 6-9, which is characterized in that examine in the direction of the current foldback circuit
Amplifier unit output end is connected to the MCU control circuit out, and the MCU control circuit receives the direction and detects amplifier unit
The detection signal of output, and according to the position detected signal magnitude and judge compressor drum, turn further according to the compressor
The position of son carries out six phase drive control of IPM.
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110160296A (en) * | 2019-05-23 | 2019-08-23 | 百尔制冷(无锡)有限公司 | Screw parallel unit electric current dynamic control method |
| CN110943437A (en) * | 2019-12-17 | 2020-03-31 | 四川长虹空调有限公司 | IPM output short circuit protection method |
| CN112003544A (en) * | 2019-05-27 | 2020-11-27 | 杭州先途电子有限公司 | Control method, control device and controller |
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| CN113690854A (en) * | 2021-08-16 | 2021-11-23 | 珠海格力电器股份有限公司 | Frequency converter protection device and method and frequency converter |
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