CN113013842A - Fan protection device - Google Patents

Fan protection device Download PDF

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Publication number
CN113013842A
CN113013842A CN201911315151.5A CN201911315151A CN113013842A CN 113013842 A CN113013842 A CN 113013842A CN 201911315151 A CN201911315151 A CN 201911315151A CN 113013842 A CN113013842 A CN 113013842A
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CN
China
Prior art keywords
fan
power
circuit
timing
operational amplifier
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Granted
Application number
CN201911315151.5A
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Chinese (zh)
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CN113013842B (en
Inventor
张顺凯
陈毅弘
廖宜庆
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Hiwin Technologies Corp
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Hiwin Technologies Corp
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Priority to CN201911315151.5A priority Critical patent/CN113013842B/en
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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
    • 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
    • H02H3/02—Details
    • H02H3/04—Details with warning or supervision in addition to disconnection, e.g. for indicating that protective apparatus has functioned
    • 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
    • H02H3/093—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 with timing means

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  • Control Of Positive-Displacement Air Blowers (AREA)
  • Control Of Electric Motors In General (AREA)

Abstract

The fan protection device comprises a power circuit, a timing circuit and a detection circuit. The power circuit supplies fan current to the fan load. The timing circuit is connected with the power circuit. The detection circuit is connected with the power circuit, the timing circuit and the fan load. When the detection circuit detects that the current of the fan meets the power-off protection condition during the running of the fan load, the timing circuit is triggered to calculate the existing time of the power-off protection condition, and when the existing time meets the timing condition, the timing circuit triggers the power supply circuit to stop supplying power to the fan load. The power-off protection condition is a power condition in which the fan current exceeds the fan load.

Description

Fan protection device
Technical Field
The present invention relates to a fan control device, and more particularly, to a fan protection device capable of detecting a fan according to an actual fan state.
Background
There are various fans for mechanical equipment, such as a radiator fan of a controller, and after a long time of operation, whether environmental dust or lubricating oil of the mechanical equipment or the like is liable to accumulate on blades or bearings of the fan, resulting in a situation where the efficiency of operation of the fan is deteriorated or even completely stationary. In this case, the fan current becomes large, and there is a serious problem that the fan is burned out.
Taiwan patent No. I288801 discloses a fan system and a temperature sensing protection device thereof, which defines a protected temperature according to the specification of the fan system, so as to prevent the fan from stopping operating when the environmental temperature exceeds the protected temperature range, thereby achieving the purpose of protection. This is referred to the ambient temperature but cannot be protected against problems with the fan itself.
Taiwan patent No. 566074 discloses a fan protection device and method, wherein when a fan is abnormal, the fan is stopped, and after a set unit cycle time, the fan is automatically started. If the number of automatic starting times reaches the set acceptable number of automatic starting times, and the abnormal state of the fan is not eliminated, the fan protection device cuts off the power supply of the fan. However, the large current generated during the repeated start-up process still causes the system to be unstable. In addition, if the abnormal reason is that the fan blades cannot rotate completely due to being blocked by dust or oil stains, the current of the fan is rapidly increased in such a way, so that the temperature of the fan is increased, and the fan is at risk of being burnt.
Disclosure of Invention
In view of the above-mentioned shortcomings, an object of the present invention is to provide a fan protection device, which can protect a fan by detecting a fan current, so that the fan protection device can be powered off in time to avoid a danger when the fan is abnormal or damaged.
In order to achieve the above object, the fan protection device of the present invention includes a power circuit, a timing circuit and a detection circuit. The power circuit supplies fan current to the fan load. The timing circuit is connected with the power circuit. The detection circuit is connected with the power circuit, the timing circuit and the fan load. When the detection circuit detects that the current of the fan meets the power-off protection condition during the running of the fan load, the timing circuit is triggered to calculate the existence time of the power-off protection condition, and when the existence time meets the timing condition, the timing circuit triggers the power supply circuit to stop supplying power to the fan load. The power-off protection condition is a power condition in which the fan current exceeds the fan load.
Therefore, the fan protection device can monitor the change of the fan current through the detection circuit, and start to calculate the existence time of the power-off protection condition when the change of the fan current meets the power-off protection condition, and then the power supply circuit stops supplying power to the fan load when the existence time meets the timing condition so as to achieve the safe operation of the fan.
The detailed structure, characteristics, operation or using mode of the fan protection device provided by the invention will be described in the following detailed description of the embodiments. However, it should be understood by those skilled in the art that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.
Drawings
FIG. 1 is a block diagram of a fan protection device according to the present invention connected to a fan load;
FIG. 2 is a circuit diagram of the fan guard of FIG. 1;
fig. 3 is a signal diagram of the fan current in fig. 1.
[ description of reference ]
10 fan protection device 11 power supply circuit 13 timing circuit
15 detection circuit 30 fan load R1 first resistor
R2 second resistor R3 third resistor R4 fourth resistor
R5 fifth resistor C1 first capacitor C2 second capacitor
D diode Q1 first transistor Q2 second transistor
Q3 third transistor Q4 fourth transistor OPA1 first operational amplifier
OPA2 second operational amplifier OPA3 third operational amplifier Vcc supply
IfFan current TfTiming conditions
Detailed Description
The components and functions of the fan protection device of the present invention will be described with reference to the accompanying drawings. However, the components, dimensions and appearance of the fan guard in the drawings are only for illustrating the technical features of the present invention and are not to be construed as limiting the present invention.
The numerical values given in the specification for parameters, conditions, and the like are only for illustrating the present invention and are not to be construed as limiting the present invention. The number of the electronic elements such as resistors or capacitors is only used for illustrating the invention in the specification or the drawings, and the number of the electronic elements such as resistors or capacitors may be more or less in other embodiments.
As shown in fig. 1, the fan protection device 10 of the present invention includes a power circuit 11, a timer circuit 13, and a detection circuit 15. The timer circuit 13 is connected to the power supply circuit 11. The detection circuit 15 is connected to the power supply circuit 11, the timer circuit 13, and the fan load 30.
The power circuit 11 is used for generating a fan current IfTo supply the operating current required by fan load 30. The detection circuit 15 is used for detecting the fan current IfWhen the power-off protection condition is satisfied, the timer circuit 13 is triggered to time, and the power circuit 11 is turned off, and the power circuit 11 which is turned off stops supplying power to the fan load 30, so as to achieve the protection purpose.
The power-off protection condition is fan current IfThe timing circuit 13 is triggered when the power-down parameter becomes large. In addition to the power-off protection condition, the present invention also provides reminder protection, which is the fan current IfWhen the value becomes smaller than the reminding parameter, a reminder is generated, in this embodiment, the reminding parameter is close to 0, which indicates that the fan load 30 stops operating. The power-off parameter is obtained by converting the power condition (e.g., maximum current value, rated current value, maximum voltage value, rated voltage value, etc.) of the reference fan load 30 into a corresponding power-off parameter, i.e., the values of the power-off parameter and the reminding parameter of different fan loads 30 may be different. Further, the manner in which the power supply condition is converted into the corresponding parameter may be obtained by a voltage-current conversion manner or the parameter may be adjusted empirically.
When fan load 30 is operating normally, fan current IfThe signal of (a) is maintained almost constant or only with small amplitude variations. When an abnormality occurs in the fan load 30, such as an increase in fan blade rotational resistance due to accumulation of oil, impurities, or other compounds, the fan current IfIt becomes larger (increased). When the fan current IfTo a greater extent to breakIn the case of the electrical parameter, the detection circuit 15 triggers the timing circuit 13 to start calculating the existence time of the power-off protection condition, and when the existence time meets the timing condition, the timing circuit 13 triggers the power supply circuit 11 to stop supplying power to the fan load 30. But the fan current IfTo the extent that the alert parameter is reduced, the protection device 10 generates an alert to let maintenance personnel know that the fan load 30 has stopped running and the fan load 30 should be replaced or repaired.
If the period of time during which the power-off protection condition exists is calculated, however, the power-off protection condition disappears, indicating the fan current IfReturning to the normal operation, the timer circuit 13 temporarily stops the timer, indicating that the power-off protection condition is not satisfied and the power supply to the fan load 30 is not stopped.
As shown in FIG. 2, the power circuit 11 includes a start-up path and a working path, and when the power circuit is started, the fan current IfThe fan current I is supplied through the start-up path of the power supply circuit 11 after the fan load 30 is normally operatedfPower is supplied through the operating path of the power circuit 11.
The start-up path includes a first resistor R1, a first capacitor C1, and a first transistor Q1. The first resistor R1 and the first capacitor C1 constitute a delay unit. The first resistor R1 is connected in series with the power source Vcc and the gate of the first transistor Q1. The first capacitor C1 is connected to the gate of the first transistor Q1 and the ground. The source of the first transistor Q1 is connected to a power supply Vcc. The drain of the first transistor Q1 is connected to the fan load 30.
The working path includes a second resistor R2, a third resistor R3, a diode D and a second transistor Q2. The second resistor R2 is connected to the gate and source of the second transistor Q2. The source of the second transistor Q2 is connected to the power supply Vcc. The third resistor R3 is connected in series between the drain of the second transistor Q2 and the anode of the diode D. The cathode of the diode D is connected to the fan load 30. The third resistor R3 and the diode D constitute a voltage unit for establishing a corresponding fan current IfA varying voltage value.
The detection circuit 15 includes a first operational amplifier OPA1, a second operational amplifier OPA2, a third transistor Q3, a fourth transistor Q4 and a fourth resistor R4, wherein the third transistor Q3, the fourth transistor Q4 and the fourth resistor R4 form a switch unit, the third transistor Q3 is a P-channel transistor, and the fourth transistor Q4 is an N-channel transistor. The non-inverting input of the first operational amplifier OPA1 is connected to the negative terminal of the diode D, and the inverting input of the first operational amplifier OPA1 receives the power-down parameter (23 volts for example in this embodiment). The inverting input terminal of the second operational amplifier OPA2 is connected to the non-inverting input terminal of the first operational amplifier OPA1, the non-inverting input terminal of the second operational amplifier OPA2 receives the alert parameter (23.6 volts is taken as an example in this embodiment), and the output terminal of the second operational amplifier OPA2 is connected to an alert device (not shown), such as a lamp, a speaker, a screen, and the like. The fourth resistor R4 is connected in series to the output of the first operational amplifier OPA1 and the gate of the third transistor Q3, and the gate of the third transistor Q3 is connected to the gate of the fourth transistor Q4. The source of the third transistor Q3 is connected to the power supply Vcc. The drain of the third transistor Q3 is connected to the drain of the fourth transistor Q4. The source of the fourth transistor Q4 is connected to ground.
The timing circuit 13 includes a fifth resistor R5, a second capacitor C2, and a third operational amplifier OPA3, and the fifth resistor R5 and the second capacitor C2 constitute a timing unit. The fifth resistor R5 is connected in series with the drain of the third transistor Q3 and the inverting input of the third operational amplifier OPA 3. The second capacitor C2 is connected to the inverting input of the third operational amplifier OPA 3. The non-inverting input of the third operational amplifier OPA3 receives the timing parameter. The output terminal of the third operational amplifier OPA3 is connected to the gate of the second transistor Q2.
The timing time of the timing circuit 13 is related to the value of the capacitor voltage of the timing unit, so the timing parameter can be adjusted according to the second capacitor C2.
At start-up, the first capacitor C1 and the conducting first transistor Q1 of the delay unit are powered by the power supply Vcc, and the second transistor Q2 is turned off to let the fan current I flowfThe fan load 30 can be powered through the startup path. In particular, the starting moment, the fan current IfIs several times larger than normal operation (for example, during Ts in fig. 3), so that the power supply through the start path can avoid triggering the detection circuit 15, and the fan load 30 can be smoothly operatedAnd (5) entering into operation. In this embodiment, Ts ranges from 500 milliseconds (ms) to 1500ms, and below 500ms, a protection failure easily occurs, which results in the fan load 30 not being able to start normally, and similarly, more than 1500ms easily causes the fan protection device 10 not to perform protection normally, and in other embodiments, the parameter range of Ts can be adjusted to be larger or smaller according to the capability of the fan load 30.
Subsequently, after the first capacitor C1 of the delay unit is fully charged, the first transistor Q1 is turned off, and the second transistor Q2 is turned on to supply the fan current IfPower can be supplied to the fan load 30 through the working path. At this time, the detection circuit 15 starts detecting the fan current IfA change in (c). Wherein, the non-inverting input terminal of the first operational amplifier OPA1 can detect the fan current I by the variation of the cathode voltage value of the diode D (i.e. the output voltage value of the voltage unit)fA change in (c). Therefore, the first capacitor C1 with different capacitance can be used to flexibly adjust the switching time of the active path and the active path.
When the fan current IfIt is normal, indicating that the power-off protection condition is not satisfied, the voltage at the non-inverting input of the first operational amplifier OPA1 is less than the power-off parameter (23 volts), and therefore the output of the first operational amplifier OPA1 triggers the fourth transistor Q4 to turn on, and the third transistor Q3 to turn off, so that the second capacitor C2 of the timing circuit 13 is not charged.
When the fan current IfBecomes large enough to satisfy the power-off protection condition (e.g., the timing condition T in fig. 3)fPeriod), the voltage at the positive input of the first OPA1 is greater than the power-down parameter (23 volts), and therefore the output of the first OPA1 triggers the third transistor Q3 to turn on and the fourth transistor Q4 to turn off, thereby triggering the timer circuit 13 to begin counting the time that the power-down protection condition exists, indicating that the fan current I is greater than the power-down parameter (23 volts)fKeeping the power-off parameter exceeded, the second capacitor C2 of the timing circuit 13 is charged until the second capacitor C2 transitions from a low voltage value to a high voltage value, indicating that the timing condition (T) is metf) The voltage value at the inverting input terminal of the third operational amplifier OPA3 is greater than the non-inverting input of the third operational amplifier OPA3With the timing parameters of the terminal, the third operational amplifier OPA3 triggers the second transistor Q2 to turn off, thereby stopping the power supply from the power circuit 11 to the fan load 30. It should be noted that the first capacitor C1 in the start-up path of the power circuit 11 is still at a high voltage value, and therefore, the first transistor Q1 is also turned off. In the present embodiment, the timing parameter is a voltage value, which refers to the time required for the second capacitor C2 to charge to a specific voltage value, and thus the timing parameter can be defined by the voltage value. In this embodiment, the timing condition TfThe parameter range of (1) is 3 seconds(s) -5 seconds(s), the misoperation of the fan load 30 caused by personnel or other reasons can be avoided when the parameter range is less than 3 seconds, the fan burnout caused by overlarge current accumulation of the fan protection device can be avoided when the parameter range is more than 5 seconds, and in other embodiments, the timing condition T isfMay also be adjusted based on fan load 30.
Thus, the timing condition can be flexibly adjusted by adjusting the timing parameter of the power condition of the fan load 30 and the capacitance of the second capacitor C2, so as to change the duration of the power-off protection condition, thereby ensuring that the fan load 30 operates in a safe state.
When the fan current IfWhen the voltage level decreases to the alert level, the alert level indicates that the voltage level at the inverting input of the second operational amplifier OPA2 exceeds the alert parameter (23.6 volts), and therefore the second operational amplifier OPA2 outputs an alert signal to let the operator know that the fan load has stopped operating.
Finally, it is emphasized that the components disclosed in the above embodiments of the present invention are merely examples and are not intended to limit the scope of the invention, and other equivalents and modifications may be substituted for the components described in the above embodiments.

Claims (10)

1. A fan protection device comprising:
a power circuit for supplying a fan current to a fan load;
a timing circuit connected to the power circuit; and
a detection circuit connected to the power circuit, the timing circuit and the fan load; when the detection circuit detects that the fan current meets a power-off protection condition during the operation of the fan load, the timing circuit is triggered to calculate the existence time of the power-off protection condition, and when the existence time meets a timing condition, the timing circuit triggers the power supply circuit to stop supplying power to the fan load, wherein the power-off protection condition is that the fan current exceeds a power supply condition of the fan load.
2. The fan protection device as claimed in claim 1, wherein the power circuit comprises a start path and a working path, the start path comprises a delay unit and a first transistor, the working path comprises a second transistor and a voltage unit, the delay unit is connected to a power source and the gate of the first transistor, the voltage unit is connected to the drain of the first transistor and the drain of the second transistor in series, the source of the first transistor and the source of the second transistor are connected to the power source, and the gate of the second transistor is connected to the timing circuit.
3. The fan protection device of claim 2, wherein the delay unit comprises a capacitor.
4. The fan protection device of claim 1, wherein the fan current meeting the power-off protection condition comprises the detection circuit comparing a voltage value corresponding to the fan current to a power-off parameter of the power condition transition.
5. The fan protection device as claimed in claim 4, wherein the detecting circuit comprises a first operational amplifier and a switch unit, wherein a non-inverting input terminal of the first operational amplifier is connected to the power circuit, an inverting input terminal of the first operational amplifier receives the power-off parameter, and the switch unit is connected to an output terminal of the first operational amplifier and the timing circuit.
6. The fan protection device as claimed in claim 5, wherein the switch unit comprises a P-channel transistor and an N-channel transistor.
7. The fan protection device of claim 5, wherein the detection circuit generates a reminder when the detection circuit detects that the fan current satisfies a reminder protection.
8. The fan protection device as claimed in claim 7, wherein the detecting circuit comprises a second operational amplifier, a non-inverting input terminal of the second operational amplifier receives a prompt parameter for the power condition transition, an inverting input terminal of the second operational amplifier is connected to the non-inverting input terminal of the first operational amplifier, and an output terminal of the second operational amplifier is used for outputting the prompt.
9. The fan protection device as claimed in claim 1 or 5, wherein the timing circuit comprises a timing unit and a third operational amplifier, the detection circuit is connected to the timing unit, a non-inverting input terminal of the third operational amplifier receives a timing parameter, an inverting input terminal of the third operational amplifier is connected to the switch unit, an output terminal of the third operational amplifier is connected to the power circuit, and the timing unit comprises a capacitor.
10. The fan protection apparatus of claim 1, wherein the timing condition is in a range of 3 seconds to 5 seconds.
CN201911315151.5A 2019-12-19 2019-12-19 Fan protector Active CN113013842B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201911315151.5A CN113013842B (en) 2019-12-19 2019-12-19 Fan protector

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Application Number Priority Date Filing Date Title
CN201911315151.5A CN113013842B (en) 2019-12-19 2019-12-19 Fan protector

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CN113013842A true CN113013842A (en) 2021-06-22
CN113013842B CN113013842B (en) 2024-05-03

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004185406A (en) * 2002-12-04 2004-07-02 Fujitsu Ten Ltd Excess current protecting apparatus
CN2907021Y (en) * 2006-03-20 2007-05-30 佛山市顺德区顺达电脑厂有限公司 Over-voltage protection circuit
CN102082426A (en) * 2011-01-07 2011-06-01 连展科技（深圳）有限公司 Current limiting circuit with output short circuit protection
CN105514960A (en) * 2015-12-03 2016-04-20 北京机械设备研究所 Hierarchically timing current-limiting protection method
CN209805407U (en) * 2019-03-19 2019-12-17 浙江大华技术股份有限公司 Short-circuit protection circuit

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004185406A (en) * 2002-12-04 2004-07-02 Fujitsu Ten Ltd Excess current protecting apparatus
CN2907021Y (en) * 2006-03-20 2007-05-30 佛山市顺德区顺达电脑厂有限公司 Over-voltage protection circuit
CN102082426A (en) * 2011-01-07 2011-06-01 连展科技（深圳）有限公司 Current limiting circuit with output short circuit protection
CN105514960A (en) * 2015-12-03 2016-04-20 北京机械设备研究所 Hierarchically timing current-limiting protection method
CN209805407U (en) * 2019-03-19 2019-12-17 浙江大华技术股份有限公司 Short-circuit protection circuit

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