CN107994545B - A kind of the protection circuit and electric system of blower - Google Patents
A kind of the protection circuit and electric system of blower Download PDFInfo
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- CN107994545B CN107994545B CN201711317602.XA CN201711317602A CN107994545B CN 107994545 B CN107994545 B CN 107994545B CN 201711317602 A CN201711317602 A CN 201711317602A CN 107994545 B CN107994545 B CN 107994545B
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- circuit
- blower
- frequency converter
- connect
- resistor
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Classifications
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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
-
- 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
- H02H7/0833—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 for electric motors with control arrangements
-
- 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
- H02H7/0855—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 avoiding response to transient overloads, e.g. during starting
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P27/00—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage
- H02P27/04—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Control Of Eletrric Generators (AREA)
- Control Of Ac Motors In General (AREA)
Abstract
The invention discloses the protection circuits and electric system of a kind of blower; the circuit includes the control circuit being arranged between blower and power supply, the Acquisition Circuit connecting with current supply circuit, the comparison circuit connecting with Acquisition Circuit, for comparing actual signal and preset signals and obtaining comparison result.Comparison circuit also with blower frequency converter in systems and control circuit connect and comparison result be transmitted to frequency converter and control circuit, control circuitry cuts blower when comparison result exception and power supply, frequency converter do respective handling.Comparison result can be transmitted to frequency converter by the comparison circuit in this protection circuit; alarm signal can be exported by being equivalent to, and frequency converter is the original frequency converter of system where blower, therefore; not needing to increase additional hardware can be realized protection to blower, and cost is relatively low.In addition, due to Acquisition Circuit acquisition be current supply circuit actual signal, be not easy to be influenced by the temperature of the working environment of blower, reliability is higher, and versatility is also relatively strong.
Description
Technical field
The present invention relates to current protection technology fields, more particularly to the protection circuit and electric system of a kind of blower.
Background technique
Heavy-duty motor has biggish fever in operation, therefore motor itself needs to carry out radiating treatment.It is general big
The blower of heat transmission is installed on power motor shell, is rotated by blower to motor radiating.The safe operation of blower is to guarantee
The precondition that heavy-duty motor operates normally, when blower appearance exception, such as when overcurrent, may cause blower can not turn
It is dynamic, it in turn results in heavy-duty motor heat dissipation and goes wrong.
In the prior art, electrothermal relay is installed on blower and realizes overcurrent protection, principle is that electrothermal relay utilizes blower
Fever allows elastic slice deformation that relay is caused to disconnect when overcurrent.But since the running environment of each blower is widely different, working environment
Temperature height can cause larger uncertain factor to the setting of over-current protection point, and electrothermal relay itself only protects overcurrent
It protects, can not directly export alarm signal under abnormal conditions.Therefore for whole system, the protective effect of electrothermal relay, which has, compares
Apparent limitation.
In addition to this, Small-power Inverter can be used in the prior art to air-blower control, can be reached using Frequency Converter Control
To good effect.But requirement of the blower to control performance itself is very low, as long as blower keeps certain air output, and general
Power of fan it is smaller can direct start-stop, the cost of system can be greatly increased using special converter driving blower, practicability is not
It is high.
It can be seen that how the realization of high reliability is that those skilled in the art are urgently to be resolved to the overcurrent protection of blower
Problem.
Summary of the invention
The object of the present invention is to provide the protection circuits and electric system of a kind of blower, and the realization for high reliability is to wind
The overcurrent protection of machine.
In order to solve the above technical problems, the present invention provides a kind of protection circuit of blower, including it is arranged in blower and power supply
Between control circuit, for controlling the on-off of the blower and power supply, being connect with the current supply circuit, for acquiring the confession
The Acquisition Circuit of the actual signal of electrical circuit, the comparison circuit connecting with the Acquisition Circuit are used for the actual signal
With preset signals and obtain comparison result；
Wherein, the comparison circuit also with the blower frequency converter in systems connect to pass the comparison result
Transport to the frequency converter, the comparison circuit also with the blower frequency converter in systems and the control circuit connect
The comparison result is transmitted to the frequency converter and the control circuit, the control circuit when the comparison result exception
The blower and the power supply are cut off, the frequency converter does respective handling.
Preferably, the control circuit specifically includes nor gate and relay；
Wherein, the first input end of the nor gate is connect with the control terminal of the frequency converter, and the second of the nor gate
Input terminal is connect with the comparison circuit, and the output end of the nor gate is connect with the coil of the relay, the relay
Contact be arranged between the blower and the power supply.
Preferably, the power supply be power frequency supply, the protection circuit further include be arranged the Acquisition Circuit with it is described
Starting current interference filter circuit between comparison circuit；
The starting current interference filter circuit specifically includes phase inverter, diode, first resistor, second resistance, third
Resistance, capacitor, switching tube；
Wherein, the input terminal of the phase inverter is connect with the output end of the nor gate, the output end of the phase inverter with
The anode of the diode connects, first end, the first end of the capacitor of the cathode of the diode and the first resistor
And the control terminal of the switching tube is all connected with, the second end of the first resistor, the second end of the capacitor, the switching tube
Second end and the second end of the second resistance be all connected with, the first of the first end of the 3rd resistor and the second resistance
End is connect with the input terminal of the comparison circuit and the Acquisition Circuit, the second end of the 3rd resistor and the switching tube
Second end connection, the switching tube is held in the contact closure of the relay, and is disconnected after preset time, institute
Preset time is stated specifically to be determined by the parameter of the first resistor and the capacitor.
Preferably, the Acquisition Circuit specifically includes three current transformers, respectively with each phase of the power frequency supply
Connection.
Preferably, further include rectification circuit between the Acquisition Circuit and the starting current interference filter circuit,
The input terminal of the rectification circuit is connect with the output end of the current transformer, the output end of the rectification circuit and described the
The first end of three resistance is connected with the first end of the second resistance.
Preferably, the comparison circuit specifically includes voltage comparator and latch；
Wherein, the first end of the non-inverting input terminal of the voltage comparator and the 3rd resistor and the second resistance
The inverting input terminal of first end connection, the voltage comparator inputs reference level, the output end of the voltage comparator and institute
The input terminal connection of latch is stated, the output end of the latch is connect with the second end of the nor gate.
Preferably, the rectification circuit is specially six pulse wave rectifier circuit of three-phase.
Preferably, the switching tube is specially NMOS, control terminal of the grid of the NMOS as the switching tube, described
First end of the drain electrode of NMOS as the switching tube, second end of the source electrode of the NMOS as the switching tube.
Preferably, the latch is specially rest-set flip-flop, input of the end S of the rest-set flip-flop as the latch
End, the end R of the rest-set flip-flop are connect as reset terminal, and with the control terminal of the frequency converter, and the end Q of the rest-set flip-flop is made
For the output end of the latch.
In order to solve the above technical problems, the present invention also provides a kind of electric system, including motor, the control motor operation
Frequency converter and be arranged at the motor for heat dissipation blower, further include the protection circuit of blower described above.
The protection circuit and electric system of blower provided by the present invention, the protection circuit, including be arranged in blower and electricity
Control circuit between source, for controlling the on-off of blower and power supply, being connect with current supply circuit, for acquiring the reality of current supply circuit
The Acquisition Circuit of border signal, the comparison circuit being connect with Acquisition Circuit, for comparing actual signal and preset signals and being compared
Relatively result.Wherein, comparison circuit also with blower frequency converter in systems and control circuit connect and transmit comparison result
To frequency converter and control circuit, circuitry cuts blower is controlled when comparison result exception and power supply, frequency converter do respective handling.By
, as it can be seen that comparison result can be transmitted to frequency converter by the comparison circuit in this protection circuit, alarm signal can be exported by being equivalent to for this
Number, and frequency converter is the original frequency converter of system where blower, and therefore, there is no need to increase additional hardware can be realized to blower
Protection, cost is relatively low.In addition, due to Acquisition Circuit acquisition be current supply circuit actual signal, be not easy by blower
The temperature of working environment influences, and reliability is higher, and versatility is also relatively strong.Finally, due to frequency converter directly controls motor,
When determining blowing machine exception, motor stopping can be directly controlled, the transmission of external signal is not needed, motor is stopped in time
Machine avoids the bad problem that radiates.
Detailed description of the invention
In order to illustrate the embodiments of the present invention more clearly, attached drawing needed in the embodiment will be done simply below
It introduces, it should be apparent that, drawings in the following description are only some embodiments of the invention, for ordinary skill people
For member, without creative efforts, it is also possible to obtain other drawings based on these drawings.
Fig. 1 is a kind of structure chart of the protection circuit of blower provided in an embodiment of the present invention；
Fig. 2 is a kind of circuit diagram of specific protection circuit provided in an embodiment of the present invention；
Fig. 3 is a kind of connection schematic diagram for protecting circuit and frequency converter provided in an embodiment of the present invention；
Fig. 4 is a kind of structure chart of electric system provided in an embodiment of the present invention.
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, rather than whole embodiments.Based on this
Embodiment in invention, those of ordinary skill in the art are without making creative work, obtained every other
Embodiment belongs to the scope of the present invention.
Core of the invention is to provide the protection circuit and electric system of a kind of blower, and the realization for high reliability is to wind
The overcurrent protection of machine.
In order to enable those skilled in the art to better understand the solution of the present invention, with reference to the accompanying drawings and detailed description
The present invention is described in further detail.
Fig. 1 is a kind of structure chart of the protection circuit of blower provided in an embodiment of the present invention.As shown in Figure 1, the protection is electric
Road, including the control circuit 12 being arranged between blower 10 and power supply 11, for controlling the on-off of blower 10 and power supply 11 and supplying
Electrical circuit connection, the Acquisition Circuit 13 of the actual signal for acquiring current supply circuit, the comparison circuit being connect with Acquisition Circuit 13
14, for comparing actual signal and preset signals and obtaining comparison result.
Wherein, comparison circuit 14 also with blower 10 frequency converter 15 in systems and the connection of control circuit 12 will compared with
As a result it is transmitted to frequency converter 15 and control circuit 12, when comparison result exception, control circuit 12 cuts off blower 10 and power supply 11,
Frequency converter 15 does respective handling.
In a particular embodiment, the system where blower 10 includes motor, and motor is high power device, in the process of running
Larger heat can be generated, if heat distributes not in time, motor is caused to be unable to operate normally, or even burn, therefore, in order to protect
Blower 10 is arranged in the normal operation for demonstrate,proving motor usually around motor, by the rotation of blower 10, accelerates motor radiating.?
In motor operation course, once blower 10 breaks down, then the normal operation of motor just not can guarantee, and how understand blower in time
10 operating status is the premise of guarantee system reliability service.
The effect of control circuit 12 is that blower 10 and power supply 11 are connected or broken by the comparison result of foundation comparison circuit 14
It opens, in specific implementation, control circuit 12 can be circuit comprising switch, such as breaker, relay etc., under specific structure
Text will be described in.
In the process of running, most direct phenomenon is exactly that the signal in current supply circuit occurs to blower 10 if there is exception
Abnormal, for example, overcurrent, therefore overvoltage etc. in the present embodiment, acquires the reality on current supply circuit by Acquisition Circuit 13
Then signal is compared with preset signals, to judge whether actual signal is normal.It is understood that actual signal can
Think voltage signal or current signal, naturally it is also possible to be temperature signal etc., corresponding, preset signals can be believed for voltage
Number, current signal or temperature signal.
The specific structure of Acquisition Circuit 13 needs the type according to acquisition target to determine, for example, if the practical letter of acquisition
Number for the voltage signal in current supply circuit, then Acquisition Circuit 13 may include voltage sensor；If the actual signal of acquisition is
Current signal in current supply circuit, then Acquisition Circuit 13 may include current sensor；If the actual signal of acquisition is power supply
Temperature signal in circuit, then Acquisition Circuit 13 may include temperature sensor, in short, the specific structure of Acquisition Circuit 13 can be with
It is set according to actual conditions, this embodiment is not limited.Due to Acquisition Circuit 13 acquire be current supply circuit actual signal, because
This is not influenced compared with the existing technology for the temperature signal of the working environment of middle acquisition blower vulnerable to the temperature of working environment,
Reliability is higher, and versatility is also relatively strong.
The specific structure of comparison circuit 14 can be using voltage comparator or operational amplifier etc., can be according to practical letter
Number type and preset signals type determine.The effect of comparison circuit 14 is to compare the size of actual signal and preset signals,
So that it is determined that whether actual signal is abnormal.When blower 10 is operating abnormally, the comparison result of comparison circuit 14 is equivalent to report
Alert signal, can directly determine whether blower 10 is abnormal by the result.
Comparison circuit 14 exports comparison result to the frequency converter 15 of 10 place system of blower, and frequency converter 15 compares according to this
As a result it can determine whether blowing machine 10 is abnormal.In addition, working as frequency conversion since frequency converter 15 directly controls motor operation
Device 15 determines that blowing machine 10 is abnormal, then can control motor stopping operation, to avoid that blower 10 is shut down and motor is still run
The problem of.In conclusion not needing additionally to increase Small-power Inverter to air-blower control, so that it may while controlling blower 10 and electricity
The operation of machine, reduces costs, moreover, frequency converter 15 functionally only increases the comparison knot for receiving comparison circuit
Fruit will not impact the control logic of frequency converter itself, meanwhile, for the scheme for additionally increasing hardware,
In the case where comparison result exception, it is also necessary to be communicated with frequency converter, frequency converter controls the mode of motor stopping again, this programme
Timeliness is higher, and more reliable.
The protection circuit of blower provided in this embodiment is used for including the control circuit being arranged between blower and power supply
The on-off of control blower and power supply is connect with current supply circuit, the Acquisition Circuit of the actual signal for acquiring current supply circuit, with adopt
The comparison circuit of collector connection, for comparing actual signal and preset signals and obtaining comparison result.Wherein, comparison circuit is also
With blower frequency converter in systems connect so that comparison result is transmitted to frequency converter, frequency converter is in comparison result exception time control
Control circuit processed disconnects the connection of blower and power supply.It can be seen that the comparison circuit in this protection circuit can be by comparison result
It is transmitted to frequency converter, alarm signal can be exported by being equivalent to, and frequency converter is the original frequency converter of system where blower, therefore,
Not needing to increase additional hardware can be realized protection to blower, and cost is relatively low.In addition, due to Acquisition Circuit acquisition be supply
Therefore the actual signal of electrical circuit is not easy to be influenced by the temperature of the working environment of blower, reliability is higher, and versatility is also relatively strong.
Finally, due to which frequency converter directly controls motor, when determining blowing machine exception, motor stopping can be directly controlled, is not required to
The transmission for wanting external signal, enables motor to shut down in time, avoids the bad problem that radiates.
Fig. 2 is a kind of circuit diagram of specific protection circuit provided in an embodiment of the present invention.It is understood that Fig. 2
A kind of specific application scenarios, those skilled in the art under the premise of obtaining this programme, by it is therein some or it is a few
A device is simply replaced, and does not need to make the creative labor, still within the scope of the present invention.Such as Fig. 2 institute
Show, on the basis of the above embodiments, preferably embodiment, control circuit 12 specifically include nor gate U3 and relay
Device.
Wherein, the control terminal CTRL connection of the first input end of nor gate U3 and frequency converter, the second input of nor gate U3
End is connect with comparison circuit 14, the coil connection of the output end of nor gate U3 and relay, the contact of relay (RLY1, RLY2,
RLY3) it is arranged between blower 10 and power supply 11.
As shown in Fig. 2, two input terminals of nor gate U3 are separately connected the control terminal CTRL and comparison circuit of frequency converter 15
14 output end, control terminal CTRL is effective using low level, when control terminal CTRL provides high level signal, then be based on or
The logic of NOT gate U3, output end are low level, and the contact of relay is disconnected in low level, therefore, as long as control terminal CTRL
High level is provided, then the contact of relay is off-state, and blower 10 and power supply 11 disconnect, and blower 10 is in shutdown status.?
When two input terminals of nor gate U3 are low level signal, output end exports high level signal, so that the contact of relay
For on-state, blower 10 is connect with power supply 11, and blower 10 is in operating status.
In above-described embodiment, power supply 11 can be any form of power supply, and in specific implementation, blower 10 is usually used
Power supply is power frequency supply, and under this kind of operating condition, there is larger current in the starting moment of blower 10, and the electric current in current supply circuit is usually volume
6-8 times of definite value, the starting current duration is shorter, and the time is usually less than 1S.In view of reducing the accident of false triggering, this implementation
In example, for the power supply mode of power frequency supply, starting current interference filter circuit 16 is increased.As shown in Fig. 2, as a kind of excellent
Selection of land embodiment, power supply 11 are power frequency supply, and protection circuit further includes being arranged between Acquisition Circuit 13 and comparison circuit 14
Starting current interference filter circuit 16.
Starting current interference filter circuit 16 specifically includes phase inverter U4, diode D1, first resistor R1, second resistance
R2,3rd resistor R3, capacitor C1, switching tube Q1；
Wherein, the output end connection of the input terminal AND OR NOT gate U3 of phase inverter U4, the output end and diode of phase inverter U4
The anode of D1 connects, the first end of the cathode of diode D1 and first resistor R1, the first end of capacitor C1 and switching tube Q1
Control terminal is all connected with, the second end of first resistor R1, the second end of capacitor C1, the second end of switching tube Q1 and second resistance R2
Second end is all connected with, the first end of the first end of 3rd resistor R3 and second resistance R2 with the input terminal of comparison circuit 14 and adopt
Collector 13 connects, and the second end of 3rd resistor R3 is connect with the second end of switching tube Q1, and switching tube Q1 is in the contact of relay
Closure moment is held on, and disconnects after preset time, and preset time is specifically determined by the parameter of first resistor and capacitor.
As shown in Fig. 2, switching tube Q1 other than metal-oxide-semiconductor, can also be IGBT or triode, Fig. 2 is a kind of specific
Application scenarios, represent only have a kind of this embodiment, other types of switching tube, this embodiment is not repeated.Fig. 2
In, switching tube Q1 is specially NMOS, and control terminal of the grid of NMOS as switching tube Q1, the drain electrode of NMOS is as switching tube Q1's
First end, second end of the source electrode Q1 of NMOS as switching tube.As shown in Fig. 2, to specifically include three electric currents mutual for Acquisition Circuit 13
Sensor T1, T2, T3 are connected with each of power frequency supply respectively.
1) before fan operation
When the control terminal CTRL of frequency converter 15 is provided high level signal (no matter comparison circuit 14 be which kind of level signal), or
The output end of NOT gate U3 exports low level signal, so that the contact of relay disconnects, blower 10 is in shutdown status.Due to or
The output end of NOT gate U3 is low level signal, and by being high level signal after phase inverter U4, electric current is flowed by diode D1
The current potential of output end of the current potential equal to phase inverter U4 on first resistor R1 and capacitor C1, final capacitor C1, so that switching tube Q1
Conducting.
2) when blower starts
When the control terminal CTRL of frequency converter 15 provides low level signal, and comparison circuit 14 also exports low level signal,
The output end of nor gate U3 exports high level signal, so that the contact of relay is closed, blower 10 brings into operation.Blower 10 with
While power supply 11 is connected, the output of phase inverter U4 becomes low level signal from high level signal before, is closed in relay
Moment, due to the effect of capacitor C1, the grid of Q1 and the voltage at source electrode both ends are still maintained as high level, then Q1, which is still maintained, leads
Logical state.Since Q1 is connected, the actual signal of sample circuit 13 passes through second resistance R2 and 3rd resistor R3 simultaneously, so output
It needs very high current that could trigger over-current signal, in other words, even if starting current is very big, loads at the both ends second resistance R2
Voltage will not be excessive, and comparison circuit 14 compares the size of the signal and preset signals, determines that the signal is less than default letter at this time
Number, blower 10 is in normal operating condition, for frequency converter 15, does not receive the abnormal signal of blower 10, then keeps controlling
End CTRL processed is low level signal.Thus excessive showing for false triggering can be caused to avoid the starting current for the moment blower 10 that closes a floodgate
As.
Since diode D1 ends after relay closure, the charge on capacitor C1 can only be released by first resistor R1, when
When capacitor C1 voltage reduces to the conducting voltage of Q1 or less, Q1 shutdown.After Q1 shutdown, the actual signal of blower 10 is only added in second
On resistance R2, therefore required overcurrent protection trigger signal will become normal level.The turn-on time of Q1 by first resistor R1 and
Capacitor C1 determines, the capacitance of the resistance value of adjustable first resistor R1 and capacitor C1 adjusts time of shielding starting current.
As shown in Fig. 2, protection circuit further includes whole between Acquisition Circuit 13 and starting current interference filter circuit 16
The input terminal of current circuit 17, rectification circuit 17 is connect with the output end of current transformer T1, T2, T3, the output of rectification circuit 17
End is connect with the first end of the first end of 3rd resistor R3 and second resistance R2.Preferably embodiment, rectification circuit 17
Specially six pulse wave rectifier circuit of three-phase.It is understood that six pulse wave rectifier circuit of three-phase is one kind of rectification circuit 17
Concrete form does not represent and there was only a kind of this form.
On the basis of the above embodiments, comparison circuit 14 specifically includes voltage comparator U1 and latch U2；
Wherein, the non-inverting input terminal of voltage comparator U1 and the first end of 3rd resistor R3 and the first end of second resistance R2
Connection, the inverting input terminal of voltage comparator U1 input reference level Vth (preset signals), the output end of voltage comparator U1 with
The input terminal of latch U2 connects, the second end connection of the output end AND OR NOT gate U3 of latch U2.
Preferably, latch U2 is specially rest-set flip-flop, input terminal of the end S of rest-set flip-flop as latch U2, RS touching
The end R of hair device is connect as reset terminal, and with the control terminal CTRL of frequency converter 15, and the end Q of rest-set flip-flop is as the defeated of latch
Outlet.
In Fig. 2, latch U2 illustrates by taking rest-set flip-flop as an example, (the control terminal of frequency converter 15 at this time after relay closure
CTRL output is low level signal), when overcurrent occurs for circuit, the voltage value of actual signal (voltages at the both ends second resistance R2) is big
In the voltage value of preset signals, voltage comparator U1 exports the input terminal S of high level signal to rest-set flip-flop, triggers rest-set flip-flop
Output end Q jump be high level signal so that the signal of the second input terminal of nor gate U3 also becomes high level signal, due to
The presence of nor gate U3, so that the output end of nor gate U3 becomes low level, then relay disconnects, fan parking.Frequency converter 15
It is connect with the output end of comparison circuit 14, then frequency converter 15 also receives high level signal.
After overcurrent triggering, the signal of current transformer T1-T3 is " 0 ", then the output end of voltage comparator U1 becomes low
Level, but since rest-set flip-flop latch signal exists, so that the second input terminal of nor gate U3 is high level signal, then or it is non-
The output end of door U3 keeps low level signal, therefore the control signal after cutting output to relay can be automatically kept as low electricity
Flat, blower 10 is in shutdown status.
For frequency converter 15, after receiving the end OC and being high level signal, respective handling can be done, such as alarm mentions
Show, cuts off motor and the connection of power supply etc..When being again started up, high level letter is first provided by the control terminal CTRL of frequency converter 15
Number, so that latch U2 resets, after reset, control terminal CTRL provides low level signal again, so that relay is allowed to be closed again,
Blower 10 is run again.
In order to allow blower in the more clear present invention of those skilled in the art to control the state of signal under each operating status
Variation, provides table 1.
Table 1
Fig. 3 is a kind of connection schematic diagram for protecting circuit and frequency converter provided in an embodiment of the present invention.As shown in figure 3, protecting
Protection circuit is connect with the common end COM of frequency converter 15, and the power supply of the component in circuit is protected to pass through the 24V electricity on frequency converter 15
Source powers, and the control terminal CTRL on frequency converter 15 is connect with the second input terminal of the nor gate U3 in protection circuit, frequency converter 15
The upper end OC is connect with the second input terminal of the nor gate U3 in protection circuit.
In above-described embodiment, for the detailed description that the protection circuit of blower provided by the invention carries out, the present invention is also mentioned
For a kind of electric system comprising the protection circuit.Fig. 4 is a kind of structure chart of electric system provided in an embodiment of the present invention.Such as
Shown in Fig. 4, electric system includes motor 30, controls the frequency converter 15 of motor operation and be arranged at motor 30 for heat dissipation
Blower 10 further includes the protection circuit of blower described above.
The protection circuit of blower provided in this embodiment is used for including the control circuit being arranged between blower and power supply
The on-off of control blower and power supply is connect with current supply circuit, the Acquisition Circuit of the actual signal for acquiring current supply circuit, with adopt
The comparison circuit of collector connection, for comparing actual signal and preset signals and obtaining comparison result.Wherein, comparison circuit is also
With blower frequency converter in systems connect comparison result be transmitted to frequency converter, frequency converter is in comparison result exception time control
Control circuit processed disconnects the connection of blower and power supply.It can be seen that the comparison circuit in this protection circuit can be by comparison result
It is transmitted to frequency converter, is disconnected by Frequency Converter Control blower and power supply, alarm signal can be exported by being equivalent to, and frequency converter is wind
The original frequency converter of system where machine, therefore, there is no need to increase additional hardware can be realized protection to blower, cost compared with
It is low.In addition, due to Acquisition Circuit acquisition be current supply circuit actual signal, be not easy the temperature of the working environment by blower
Degree influences, and reliability is higher, and versatility is also relatively strong.Finally, due to which frequency converter directly controls motor, determining that blowing machine is different
Chang Shi can directly control motor stopping, do not need the transmission of external signal, motor is shut down in time, avoid
Radiate bad problem.
The protection circuit and electric system of blower provided by the present invention are described in detail above.It is each in specification
A embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments, respectively
Same and similar part may refer to each other between a embodiment.For the device disclosed in the embodiment, due to itself and embodiment
Disclosed method is corresponding, so being described relatively simple, reference may be made to the description of the method.It should be pointed out that pair
For those skilled in the art, without departing from the principle of the present invention, the present invention can also be carried out
Some improvements and modifications, these improvements and modifications also fall within the scope of protection of the claims of the present invention.
It should also be noted that, in the present specification, relational terms such as first and second and the like be used merely to by
One entity or operation are distinguished with another entity or operation, without necessarily requiring or implying these entities or operation
Between there are any actual relationship or orders.Moreover, the terms "include", "comprise" or its any other variant meaning
Covering non-exclusive inclusion, so that the process, method, article or equipment for including a series of elements not only includes that
A little elements, but also including other elements that are not explicitly listed, or further include for this process, method, article or
The intrinsic element of equipment.In the absence of more restrictions, the element limited by sentence "including a ...", is not arranged
Except there is also other identical elements in the process, method, article or apparatus that includes the element.
Claims (9)
1. a kind of protection circuit of blower, which is characterized in that including being arranged between blower and power supply, for controlling the blower
With the control circuit of the on-off of power supply, it is connect with the current supply circuit of the blower, the practical letter for acquiring the current supply circuit
Number Acquisition Circuit, and with Acquisition Circuit connection, for the actual signal and preset signals and compared with obtaining
As a result comparison circuit；
Wherein, the comparison circuit also with the blower frequency converter in systems and the control circuit connect with will be described
Comparison result is transmitted to the frequency converter and the control circuit, and when the comparison result exception, the control circuit cuts off institute
Blower and the power supply are stated, the frequency converter does respective handling；
The control circuit includes nor gate and relay；
Wherein, the first input end of the nor gate is connect with the control terminal of the frequency converter, the second input of the nor gate
End is connect with the comparison circuit, and the output end of the nor gate is connect with the coil of the relay, the touching of the relay
Point is arranged between the blower and the power supply.
2. the protection circuit of blower according to claim 1, which is characterized in that the power supply is power frequency supply, the guarantor
Protection circuit further includes the starting current interference filter circuit being arranged between the Acquisition Circuit and the comparison circuit；
The starting current interference filter circuit includes phase inverter, diode, first resistor, second resistance, 3rd resistor, electricity
Hold, switching tube；
Wherein, the input terminal of the phase inverter is connect with the output end of the nor gate, the output end of the phase inverter with it is described
The anode of diode connects, the first end of the cathode of the diode and the first resistor, the first end of the capacitor and
The control terminal of the switching tube is all connected with, the second end of the first resistor, the second end of the capacitor, the switching tube
The second end of two ends and the second resistance is all connected with, and the first end of the 3rd resistor and the first end of the second resistance are equal
It is connect with the input terminal of the comparison circuit and the Acquisition Circuit, the of the second end of the 3rd resistor and the switching tube
One end connection, the switching tube is held in the contact closure of the relay, and is disconnected after preset time, described pre-
If the time is specifically determined by the parameter of the first resistor and the capacitor.
3. the protection circuit of blower according to claim 2, which is characterized in that the Acquisition Circuit includes that three electric currents are mutual
Sensor is connected with each of the power frequency supply respectively.
4. the protection circuit of blower according to claim 2, which is characterized in that further include in the Acquisition Circuit and described
Rectification circuit between starting current interference filter circuit, the output of the input terminal of the rectification circuit and the current transformer
End connection, the output end of the rectification circuit are connect with the first end of the first end of the 3rd resistor and the second resistance.
5. according to the protection circuit of blower described in claim 2-4 any one, which is characterized in that the comparison circuit includes
Voltage comparator and latch；
Wherein, the first of the first end and the second resistance of the non-inverting input terminal of the voltage comparator and the 3rd resistor
The inverting input terminal of end connection, the voltage comparator inputs reference level, the output end of the voltage comparator and the lock
The input terminal of storage connects, and the output end of the latch is connect with the second input terminal of the nor gate.
6. the protection circuit of blower according to claim 4, which is characterized in that the rectification circuit is that six pulse wave of three-phase is whole
Current circuit.
7. the protection circuit of blower according to claim 2, which is characterized in that the switching tube is NMOS, the NMOS
Control terminal of the grid as the switching tube, first end of the drain electrode of the NMOS as the switching tube, the NMOS's
Second end of the source electrode as the switching tube.
8. the protection circuit of blower according to claim 5, which is characterized in that the latch is rest-set flip-flop, described
Input terminal of the end S of rest-set flip-flop as the latch, the end R of the rest-set flip-flop as reset terminal, and with the frequency conversion
The control terminal of device connects, output end of the end Q of the rest-set flip-flop as the latch.
9. a kind of electric system is used at the motor including motor, the frequency converter of the control motor operation and setting
The blower of heat dissipation, which is characterized in that further include the protection circuit of blower described in claim 1-8 any one.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201711317602.XA CN107994545B (en) | 2017-12-12 | 2017-12-12 | A kind of the protection circuit and electric system of blower |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201711317602.XA CN107994545B (en) | 2017-12-12 | 2017-12-12 | A kind of the protection circuit and electric system of blower |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN107994545A CN107994545A (en) | 2018-05-04 |
| CN107994545B true CN107994545B (en) | 2019-07-30 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201711317602.XA Active CN107994545B (en) | 2017-12-12 | 2017-12-12 | A kind of the protection circuit and electric system of blower |
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| Country | Link |
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| CN (1) | CN107994545B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110429566A (en) * | 2019-08-19 | 2019-11-08 | 广东美的制冷设备有限公司 | Blower current-limiting circuit and equipment |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201130849Y (en) * | 2007-12-17 | 2008-10-08 | 南通三九焊接机器制造有限公司 | Abnormal condition protected unit system for wind cooling system |
| CN101710694B (en) * | 2009-11-26 | 2012-12-19 | 上海大学 | Car engine cooling fan blocking/overcurrent protection system and method |
| CN203233141U (en) * | 2013-03-13 | 2013-10-09 | 中国石油天然气股份有限公司 | Chain protection device of independent cooling fan of variable frequency motor |
| CN206225995U (en) * | 2016-11-22 | 2017-06-06 | 广东美的暖通设备有限公司 | The typhoon power protecting circuit of outdoor fan, outdoor unit and air-conditioner in air-conditioner |
| CN106452200B (en) * | 2016-11-22 | 2019-02-19 | 广东美的暖通设备有限公司 | Typhoon power protecting circuit, outdoor unit and the air conditioner of outdoor fan in air conditioner |
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2017
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Also Published As
| Publication number | Publication date |
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| CN107994545A (en) | 2018-05-04 |
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