Fan monitoring system

Abstract

The utility model provides a fan monitoring system, which relates to the technical field of equipment detection and comprises a plurality of high-pass filtering modules, an AND gate module and a state comparison module. The input ends of the high-pass filtering modules are connected with the fan feedback signal output end, the output ends of the high-pass filtering modules are all connected with the input end of the AND gate module, and the AND gate module and the state comparison module are sequentially connected. When the fan breaks down, no matter whether the feedback signal is a high level or a low level, the output signal of the high-pass filtering module is the first level, and therefore even if the fan breaks down when rotating to the high level, it can be recognized that the fan is in the fault state; if the output of any high-pass filtering module is the first level, the AND gate module outputs the first level, and the state comparison module judges whether the fan has a fault according to the level output by the AND gate module, for example, if the AND gate module outputs the first level, it is indicated that the fan has the fault at the moment, and monitoring of multiple fans with different feedback frequencies is achieved; the system adaptability is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of equipment detection, in particular to a fan monitoring system. Background Art

[0002] Heat is generated during the operation of the equipment. If the equipment is not cooled in time, it may be damaged due to high temperature or shut down due to high temperature alarm. The commonly used cooling methods currently include cooling with heat sinks, cooling with circulating coolant, or cooling with cooling fans. When the cooling fan is running, the air flow around the equipment is increased, and the cold air is circulated around the equipment for cooling, and the heat around the equipment is blown away in time.

[0003] In order to ensure the normal operation of the equipment, it is necessary to monitor the operating status of the cooling fan in real time to avoid the accumulation of heat around the equipment due to the failure of the cooling fan, causing high temperature damage to the equipment or forced shutdown. At present, the monitoring of the fan operating status is to use the speed feedback signal output by the fan to determine whether the fan is faulty. Among them, the speed feedback signal has both high level and low level, and the existing fan operating status monitoring method can only detect high level or low level. When there are multiple fans, the feedback signals of multiple fans are not necessarily at a high level or at a low level at the same time. For example, when a fan has a high level fault, the feedback signal of the fan will always be at a high level. If the fan operating status monitoring method is to detect the low level, this fault state cannot be monitored. Therefore, the existing detection method has poor adaptability to multiple fans with different feedback frequencies running simultaneously. Utility Model Content

[0004] The problem to be solved by the utility model is that the existing method for monitoring the operating status of a fan has poor adaptability to a plurality of fans with different feedback frequencies running simultaneously.

[0005] To solve the above problems, on the one hand, the utility model provides a fan monitoring system, including a plurality of high-pass filter modules, an AND gate module and a state comparison module;

[0006] The multiple high-pass filter modules correspond one-to-one to the multiple fans, the input end of each high-pass filter module is respectively used to be connected to the feedback signal output end of the corresponding fan, the output ends of the multiple high-pass filter modules are all connected to the input end of the AND gate module, and the output end of the AND gate module is connected to the input end of the state comparison module.

[0007] Optionally, the high-pass filter module includes a clamped high-pass filter, an input end of the clamped high-pass filter serves as the input end of the high-pass filter module, and an output end of the clamped high-pass filter serves as the output end of the high-pass filter module.

[0008] Optionally, the clamped high-pass filter includes a first capacitor, a second capacitor, a first resistor, a second resistor, a third resistor, a first diode and a second diode, one end of the first capacitor serving as the input end of the clamped high-pass filter and being connected to the feedback signal output end of the fan, one end of the first capacitor being also connected to one end of the second resistor, the other end of the second resistor being used to be connected to a first power supply, the other end of the first capacitor being respectively connected to the positive electrode of the second diode and the negative electrode of the first diode, the positive electrode of the first diode being grounded, the negative electrode of the second diode being connected to one end of the third resistor, the other end of the third resistor being respectively connected to one end of the first resistor and one end of the second capacitor, the other end of the first resistor and the other end of the second capacitor being grounded respectively, and the other end of the third resistor serving as the output end of the clamped high-pass filter and being connected to the input end of the AND gate module.

[0009] Optionally, the AND gate module includes an AND gate circuit, which includes multiple circuit input terminals and circuit output terminals. The multiple circuit input terminals serve as multiple input terminals of the AND gate module and are connected one-to-one with the output terminals of the multiple high-pass filter modules; the circuit output terminal serves as the output terminal of the AND gate module and is connected to the input terminal of the state comparison module.

[0010] Optionally, the AND gate circuit includes multiple AND gate diodes and a fourth resistor, and the cathodes of the multiple AND gate diodes serve as the multiple circuit input terminals of the AND gate circuit, and are connected one-to-one with the output terminals of the multiple high-pass filtering modules; the anode of each of the AND gate diodes is connected to one end of the fourth resistor, and the other end of the fourth resistor is used to be connected to the first power supply, and the connection point formed by the anodes of each of the AND gate diodes serves as the circuit output terminal of the AND gate circuit, and is connected to the input terminal of the state comparison module.

[0011] Optionally, the AND gate module includes an AND gate chip, the AND gate chip includes multiple input pins and output pins, the multiple input pins correspond to the output pins, the multiple input pins serve as multiple input ends of the AND gate module, and are connected one-to-one with the output ends of the multiple high-pass filter modules; the output pin serves as the output end of the AND gate module, and is connected to the input end of the state comparison module.

[0012] Optionally, the state comparison module includes a comparator, a fifth resistor, a seventh resistor, an eighth resistor, a third capacitor and a fourth capacitor;

[0013] The inverting input end of the comparator serves as the input end of the state comparison module and is connected to the output end of the AND gate module; the non-inverting input end of the comparator is respectively connected to one end of the fifth resistor and one end of the third capacitor, the other end of the fifth resistor is used to be connected to a reference power supply, and the other end of the third capacitor is grounded; the output end of the comparator is respectively connected to one end of the seventh resistor and one end of the eighth resistor, the other end of the seventh resistor is used to be connected to a second power supply, the other end of the eighth resistor is connected to one end of the fourth capacitor, the other end of the fourth capacitor is grounded, and the other end of the eighth resistor also serves as the output end of the state comparison module.

[0014] Optionally, the state comparison module also includes a fourth diode and a sixth resistor, the anode of the fourth diode is connected to the non-inverting input terminal of the comparator, the cathode of the fourth diode is connected to one end of the sixth resistor, and the other end of the sixth resistor is connected to the output terminal of the comparator.

[0015] Optionally, the state comparison module includes a NOT gate circuit, an input end of the NOT gate circuit serves as the input end of the state comparison module and is connected to the output end of the AND gate module; and an output end of the NOT gate circuit serves as the output end of the state comparison module.

[0016] Optionally, the fan monitoring system further includes a processing module, and an input end of the processing module is connected to an output end of the state comparison module.

[0017] Compared with the prior art, the utility model has the following beneficial effects:

[0018] The utility model provides a fan monitoring system, wherein a plurality of high-pass filter modules correspond to a plurality of fans one by one, and a feedback signal of each fan is input into a corresponding high-pass filter module, and the high-pass filter module is used to convert the feedback signal into a level. When the fan fails, no matter the feedback signal is at a high level or a low level, the feedback signal remains unchanged, and the output signal of the high-pass filter module is the first level (for example, a low level). Therefore, no matter the fan has a high-level fault or a low-level fault, it can be identified that the fan is in a fault state; when the fan has no fault, the feedback signal is a continuously changing signal, such as a PWM signal, and the output signal of the high-pass filter module is a second level (for example, a high level); each high-pass filter module identifies and converts the feedback signal of each fan respectively, and multiple high-pass filter modules input the conversion results to the AND gate module, and the AND gate module performs AND operation on the outputs of multiple high-pass filter modules. If the output of any high-pass filter module is the first level, the AND gate module outputs the first level; the state comparison module determines whether the fan has a fault according to the level output by the AND gate module. For example, if the AND gate module outputs the second level, it means that there is no fan fault; if the AND gate module outputs the first level, it means that there is a fan fault at this time, thereby realizing the monitoring of multiple fans with different feedback frequencies and improving the adaptability of the fan monitoring system. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the structure of a fan monitoring system in an embodiment of the utility model;

[0020] Figure 2 This is a circuit diagram of a fan monitoring system in an embodiment of the utility model;

[0021] Figure 3 It is a schematic diagram of waveforms of each monitoring point in the fan monitoring system when the fan has no fault in the embodiment of the utility model;

[0022] Figure 4 It is a schematic diagram of waveforms of each monitoring point in the fan monitoring system when a fan fails in an embodiment of the utility model;

[0023] Figure 5 This is a schematic diagram of the structure of an AND gate chip in an embodiment of the utility model;

[0024] Figure 6 It is a structural schematic diagram of a NOT gate circuit in an embodiment of the utility model. DETAILED DESCRIPTION

[0025] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and understandable, the specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0026] It should be noted that the terms "first", "second", etc. in the specification and claims of the utility model and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the utility model described here can be implemented in an order other than those illustrated or described here.

[0027] In the description of this specification, the description with reference to the terms "embodiment", "one embodiment" and "one implementation" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or implementation are included in at least one embodiment or implementation of the utility model. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or implementation. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or implementations in a suitable manner.

[0028] The cooling fan has multiple function signal lines, some of which are used to input control signals to the cooling fan to control the cooling fan operation; some of which are used to feedback the fan operation status signal. FG (FrequncyGenerator) is the cooling fan frequency generator, and the FG feedback signal is used to detect the fan speed. When the fan is running, the switching of the N and S poles of the rotor will produce high and low level changes, forming a continuous square wave signal (i.e., FG feedback signal). The faster the speed, the faster the level changes, so the fan speed can be detected by the changing frequency.

[0029] In the embodiment of the present utility model, Figure 1 As shown, the fan monitoring system includes a plurality of high-pass filter modules, an AND gate module and a state comparison module;

[0030] The multiple high-pass filter modules correspond one-to-one to the multiple fans, the input end of each high-pass filter module is respectively used to be connected to the feedback signal output end of the corresponding fan, the output ends of the multiple high-pass filter modules are all connected to the input end of the AND gate module, and the output end of the AND gate module is connected to the input end of the state comparison module.

[0031] Specifically, in Figure 1In the embodiment, the fan monitoring system has multiple input terminals, each of which corresponds to a fan feedback signal, namely, fan feedback signal 1, fan feedback signal 2 to fan feedback signal N. The normally input feedback signal is a PWM signal of different frequencies. If the fan fails, the feedback signal may be high or low. The multiple high-pass filter modules correspond to the multiple fans one by one. Each fan feedback signal is input into the corresponding high-pass filter module. The high-pass filter module is used to convert the feedback signal into a level. The high-pass filter module can be a clamped high-pass filter. When the fan is not faulty, the feedback signal is a continuously changing PWM signal, and the output signal of the high-pass filter module is the second level; when the fan fails, no matter the feedback signal is high or low, the output signal of the high-pass filter module is the first level. Taking the first level as a low level and the second level as a high level as an example, the AND gate module is used to perform AND operations on the outputs of multiple high-pass filter modules. If the output of any high-pass filter module is low (i.e., any input of the AND gate module is low), the AND gate module outputs a low level, indicating that at least one of the multiple fans has failed. The state comparison module is used to judge the output value of the AND gate module so as to identify whether there is a fault in multiple fans. When the AND gate module outputs a high level, the state comparison module can output a low level, indicating that there is no fan fault at this time; when the AND gate module outputs a low level, the state comparison module can output a high level, indicating that there is a fan fault at this time.

[0032] In this embodiment, a plurality of high-pass filter modules correspond to a plurality of fans one by one, and a feedback signal of each fan is input into a corresponding high-pass filter module, and the high-pass filter module is used to convert the feedback signal into a level. When the fan fails, no matter the feedback signal is at a high level or a low level, the feedback signal remains unchanged, and the output signal of the high-pass filter module is the first level (for example, a low level). Therefore, no matter the fan has a high-level fault or a low-level fault, it can be identified that the fan is in a fault state; when the fan has no fault, the feedback signal is a continuously changing signal, such as a PWM signal, and the output signal of the high-pass filter module is a second level (for example, a high level); each high-pass filter module identifies and converts the feedback signal of each fan respectively, and multiple high-pass filter modules input the conversion results to the AND gate module, and the AND gate module performs AND operation on the outputs of multiple high-pass filter modules. If the output of any high-pass filter module is the first level, the AND gate module outputs the first level; the state comparison module is used to judge the output value of the AND gate module. If the AND gate module outputs the second level, the state comparison module outputs a low level, indicating that there is no fan fault; if the AND gate module outputs the first level, the state comparison module outputs a high level, indicating that there is a fan fault at this time, thereby realizing the monitoring of multiple fans with different feedback frequencies and improving the adaptability of the fan monitoring system.

[0033] Optionally, the high-pass filter module includes a clamped high-pass filter, an input end of the clamped high-pass filter serves as the input end of the high-pass filter module, and an output end of the clamped high-pass filter serves as the output end of the high-pass filter module.

[0034] Specifically, a clamped high-pass filter is a special type of high-pass filter that limits the amplitude of the signal to a specific range during the filtering process. This filter can be used to remove low-frequency noise or interference while retaining the details of high-frequency signals. Figure 1 As shown, the fan feedback signal 1, the fan feedback signal 2 to the fan feedback signal N correspond one-to-one to the clamped high-pass filter 1, the clamped high-pass filter 2 to the clamped high-pass filter N respectively.

[0035] In this optional embodiment, when the fan is operating normally and the feedback signal maintains a square wave signal that changes periodically continuously, the clamped high-pass filter outputs a high level; when the fan fails, the fan may fail in the first half of the cycle or the fan fails in the second half of the cycle, and the feedback signal maintains a high level or a low level unchanged. At this time, the clamped high-pass filter outputs a low level, thereby being able to accurately identify the fault state of the fan.

[0036] In an optional embodiment, if Figure 2 As shown, the clamped high-pass filter includes a first capacitor, a second capacitor, a first resistor, a second resistor, a third resistor, a first diode and a second diode, one end of the first capacitor serves as an input end of the clamped high-pass filter and is used to be connected to the feedback signal output end of the fan, one end of the first capacitor is also connected to one end of the second resistor, the other end of the second resistor is used to be connected to a first power supply VCC, the other end of the first capacitor is respectively connected to the positive electrode of the second diode and the negative electrode of the first diode, the positive electrode of the first diode is grounded, the negative electrode of the second diode is connected to one end of the third resistor, the other end of the third resistor is respectively connected to one end of the first resistor and one end of the second capacitor, the other end of the first resistor and the other end of the second capacitor are grounded respectively, and the other end of the third resistor serves as the output end of the clamped high-pass filter and is connected to the input end of the AND gate module.

[0037] For example, taking monitoring of two fans as an example, a fan with FG signal feedback is connected to the input end of the fan monitoring system. The fan with FG signal feedback refers to a fan that feeds back a 5V PWM signal under normal circumstances. Each fan corresponds to a clamped high-pass filter. Figure 2In the embodiment, the fan monitoring system inputs the fan feedback signal 1 and the fan feedback signal 2 respectively. The fan feedback signal 1 and the fan feedback signal 2 can be PWM feedback signals of different frequencies. When the fan motor encounters a fault when rotating to the first half of the cycle, the feedback signal will always be at a high level (+5V). When the fan motor encounters a fault when rotating to the second half of the cycle, the feedback signal will always be at a low level (0V). Then, the fan feedback signals of different frequencies are input into the clamped high-pass circuit. The clamped high-pass filter 1 corresponding to the fan feedback signal 1 includes: a first capacitor C1, a second capacitor C2, a first resistor R1, a second resistor R2, a third resistor R3, a first diode D1 and a second diode D2; the clamped high-pass filter 2 corresponding to the fan feedback signal 1 includes: a first capacitor C5, a second capacitor C6, a first resistor R11, a second resistor R12, a third resistor R13, a first diode D5 and a second diode D6. Two monitoring points are respectively set at the connection between the first capacitor and the first resistor and at the connection between the first capacitor and the first diode, and a monitoring point is set at the connection between the second resistor and the third resistor. The monitoring points in the two clamped high-pass filters are A1, B1 and E1 and A2, B2 and E2 respectively. Due to the existence of the high-pass clamp filter, if the fan has no faults, when a PWM signal is input to the input end of the high-pass clamp filter, the signal can pass through the high-pass clamp filter normally. Figure 3 The waveforms of each monitoring point when both fans are fault-free are shown. If the potential at the front end of the first capacitor (C1 and C5) changes, a negative voltage will be generated at the rear end of the first capacitor because the voltage of the first capacitor cannot change suddenly. The potential is clamped at –0.6V by the clamping action of the first diode (D1 and D5), and the second diode (D2 and D6) is used to limit the current direction. At this time, the PWM signal charges the second capacitor (C2 and C6), as shown in Figure 1. Figure 3 , the voltages at monitoring points E1 and E2 are both at a high level, so when the fan is not faulty, the clamped high-pass filter outputs are all high levels. In addition, the change in the potential at the rear end of the first capacitor of the input PWM wave causes the current to oscillate, so adding the first diode and the second diode can ensure the stability of the output. When the fan fails, take the failure of the second fan as an example, that is, the fan feedback signal is abnormal, not a PWM signal, such as Figure 4 As shown, when the fan feedback signal 2 is at a high level or a low level, the input terminal voltage and the voltage of the first capacitor C5 will remain consistent, and the input feedback signal cannot cause the rear end of the first capacitor to change, that is, it cannot pass through the first capacitor. The voltage at the rear end of the first capacitor is at a low level. Therefore, when a fault occurs, there is no voltage to charge the second capacitor C6, and the voltage at the monitoring point E2 is at a 0 level. Therefore, when the fan fails, the clamped high-pass filter outputs a 0 level.

[0038] Optionally, the AND gate module includes an AND gate circuit, which includes multiple circuit input terminals and circuit output terminals. The multiple circuit input terminals serve as multiple input terminals of the AND gate module and are connected one-to-one with the output terminals of the multiple high-pass filter modules; the circuit output terminal serves as the output terminal of the AND gate module and is connected to the input terminal of the state comparison module.

[0039] In an optional embodiment, if Figure 2 As shown, the AND gate circuit includes multiple AND gate diodes and a fourth resistor R4, the cathodes of the multiple AND gate diodes serve as multiple circuit input terminals of the AND gate circuit, and are connected one-to-one with the output terminals of the multiple high-pass filtering modules; the anode of each of the AND gate diodes is connected to one end of the fourth resistor R4, and the other end of the fourth resistor R4 is used to be connected to the first power supply VCC, and the connection point formed by the anodes of each of the AND gate diodes serves as the circuit output terminal of the AND gate circuit, and is connected to the input terminal of the state comparison module.

[0040] Specifically, Figure 2 As shown, the AND gate diodes are D3 and D7, and the two AND gate diodes correspond to the clamped high-pass filter 1 and the clamped high-pass filter 2, respectively. The cathode of the AND gate diode D3 is connected to the other end of the third resistor R3, and the cathode of the AND gate diode D7 is connected to the other end of the third resistor R13. When the two clamped high-pass filters output a low level (0V) at the same time, since the voltage at point F is VCC, the AND gate diodes D3 and D7 are both turned on, and the voltage at point F immediately drops to 0.7V (low level), that is, when the input ends of the AND gate circuit are all input with a low level, the output end outputs a low level. When the clamped high-pass filter 1 outputs a high level and the clamped high-pass filter 2 outputs a low level, since the voltage at point E is VCC, the AND gate diode D7 is immediately turned on, and the voltage at point F drops to 0.7V, so that the positive terminal voltage of the AND gate diode D3 is also 0.7V, and the negative terminal voltage is a high level (5V), and the AND gate diode D3 is in the cut-off state, that is, when the clamped high-pass filter 1 outputs a high level and the clamped high-pass filter 2 outputs a low level, the monitoring point F at the output end of the AND gate circuit outputs a low level, such as Figure 4 As shown. Similarly, when the clamped high-pass filter 1 outputs a low level and the clamped high-pass filter 2 outputs a high level, the AND gate circuit outputs a low level. When the two clamped high-pass filters output a high level (5V) at the same time, the AND gate diodes D3 and D7 cannot be turned on, and the voltage at point F is VCC (high level), that is, when the input ends of the AND gate circuit are all input with a high level "1", the output end outputs a high level "1". It can be seen that the characteristics of the AND gate are: the output end will output a high level only when the input ends are all input with a high level; as long as one of the input ends inputs a low level, the output end will output a low level, such as Figure 4 shown.

[0041] In this embodiment, after passing through the clamped high-pass filter, since feedback signals of different frequencies are input to the clamped high-pass filter, if the output ends of different clamped high-pass filters are directly connected, the signals output by the clamped high-pass filters will be superimposed on each other, and false detection will occur. Here, an AND gate circuit with a diode is added for isolation operation. The outputs of multiple clamped high-pass filters are input to the AND gate circuit for AND operation. If any one or more inputs are at a low level, that is, there is a fault, the AND gate circuit output is a low level.

[0042] In an optional embodiment of the present utility model, as Figure 5 As shown, the AND gate module includes an AND gate chip, and the AND gate chip includes multiple input pins and output pins, multiple input pins correspond to the output pins, and multiple input pins serve as multiple input ends of the AND gate module, and are connected one-to-one with the output ends of multiple high-pass filter modules; the output pin serves as the output end of the AND gate module, and is connected to the input end of the state comparison module.

[0043] In this embodiment, the AND gate chip has multiple sets of corresponding input terminals and output terminals, such as input terminals 1A and 1B and output terminal 1Y, input terminals 2A and 2B and output terminal 2Y, and the combination of Figure 2 In this example, only input terminals 1A and 1B and output terminal 1Y are used, and the outputs of clamped high-pass filter 1 and clamped high-pass filter 2 (i.e., the levels of monitoring point E1 and monitoring point E2) are input to input terminals 1A and 1B respectively, and the output of output terminal 1Y is the level of monitoring point F; input terminals 2A and 2B and output terminal 2Y, input terminals 3A and 3B and output terminal 3Y, input terminals 4A and 4B and output terminal 4Y are not used and are all grounded. The AND gate chip performs AND operation on the two signals at the input terminals, and then outputs the structure from the corresponding output terminal. It can also achieve that as long as one input terminal inputs a low level, the output terminal will output a low level; only when both input terminals input a high level, the output terminal will output a high level.

[0044] In an optional embodiment of the present utility model, as Figure 2 As shown, the state comparison module includes a comparator, a fifth resistor R5, a seventh resistor R7, an eighth resistor R8, a third capacitor C3 and a fourth capacitor C4;

[0045] The inverting input end of the comparator serves as the input end of the state comparison module and is connected to the output end of the AND gate module; the non-inverting input end of the comparator is respectively connected to one end of the fifth resistor R5 and one end of the third capacitor C3, the other end of the fifth resistor R5 is used to be connected to a reference power supply, the other end of the third capacitor C3 is grounded, the output end of the comparator is respectively connected to one end of the seventh resistor R7 and one end of the eighth resistor R8, the other end of the seventh resistor R7 is used to be connected to a second power supply, the other end of the eighth resistor R8 is connected to one end of the fourth capacitor C4, the other end of the fourth capacitor C4 is grounded, and the other end of the eighth resistor R8 also serves as the output end of the state comparison module.

[0046] Specifically, the comparator can select an LM239 comparator, the comparator is powered by a single power supply, the other end of the fifth resistor R5 is connected to the reference power supply, and the other end of the third capacitor C3 is grounded. The fifth resistor R5 and the third capacitor C3 filter the signal input to the inverting input terminal of the comparator to ensure that the signal input to the inverting input terminal of the comparator is stable. The eighth resistor R8 and the fourth capacitor C4 filter the signal output from the output terminal of the comparator to ensure that the output signal is stable. The other end of the seventh resistor R7 is connected to the second power supply, and the high level of the output terminal is adjusted to the required voltage level by adjusting the voltage VDD of the second power supply.

[0047] In this embodiment, when the comparator reverse input terminal input is high level, the comparator reverse input terminal voltage is greater than the comparator non-inverting input terminal voltage, the comparator output terminal outputs low level, then the G point potential is low level, it is judged that there is no fan fault, such as Figure 3 The waveform of monitoring point G is shown in Figure 1. When the comparator reverse input terminal input is low level, the voltage of the comparator reverse input terminal is less than the voltage of the comparator non-inverting input terminal, and the comparator output terminal outputs high level, then the potential of point G is high level, and it is judged that there is a fan fault, such as Figure 4 The waveform of monitoring point G is shown to complete fault detection.

[0048] In an optional embodiment, if Figure 2 As shown, the state comparison module also includes a fourth diode and a sixth resistor, the anode of the fourth diode is connected to the in-phase input terminal of the comparator, the cathode of the fourth diode is connected to one end of the sixth resistor, and the other end of the sixth resistor is connected to the output terminal of the comparator.

[0049] Specifically, the in-phase input terminal of the comparator is connected to the output terminal through the sixth resistor R6 to form a feedback loop, so that the comparator has a hysteresis characteristic. Even if the input voltage fluctuates slightly, as long as the fluctuation of the jump voltage does not exceed a certain value, the output voltage remains stable. The hysteresis comparator formed in this way can also avoid the self-oscillation problem caused by circuit coupling. The unidirectional conductivity of the fourth diode D4 is used to clamp and protect, limiting the voltage of the output signal of the comparator within a certain range.

[0050] In an optional embodiment of the present utility model, as Figure 6 As shown, the state comparison module includes a NOT gate circuit, the input end of the NOT gate circuit serves as the input end of the state comparison module and is connected to the output end of the AND gate module; the output end of the NOT gate circuit serves as the output end of the state comparison module.

[0051] Specifically, Figure 6 As shown, the NOT gate circuit includes a ninth resistor R9, a tenth resistor R10 and a transistor, one end of the ninth resistor R9 serves as the input end of the state comparison module and is connected to the output end of the AND gate module; the other end of the ninth resistor R9 is connected to the base of the transistor, the collector of the transistor is connected to one end of the tenth resistor R10, the other end of the tenth resistor R10 is connected to the positive electrode of the power supply, the collector of the transistor serves as the output end of the state comparison module; the emitter of the transistor is grounded.

[0052] Specifically, when there is no fault, the voltage at point F is high, and the output voltage after passing through the NOT gate circuit is low; when there is a fault, the voltage at point F is low, and the voltage after passing through the NOT gate is high. When point F is low, the transistor is in the cut-off state, and the output voltage at point G is VCC; when point F is high, the transistor is saturated and turned on, and the output voltage at point G is low.

[0053] Alternatively, if Figure 1 As shown, the fan monitoring system further includes a processing module, and an input end of the processing module is connected to an output end of the state comparison module.

[0054] Specifically, Figure 2As shown, the processing module can be a DSP (digital signal processor). The state comparison module outputs a low level, indicating that there is no fan failure. The low level of the state comparison module does not trigger the DSP, and the DSP does not generate a reminder message; the state comparison module outputs a high level, indicating that there is a fan failure. The high level of the state comparison module triggers the DSP, and the DSP generates a reminder message. The reminder message can be sent to the control center or directly to the mobile terminal of the maintenance personnel, so that the relevant personnel can be informed of the operation of the fan in time, so as to remind the staff to check the operation of the fan on site in time and eliminate the fault. When the fan has no fault, the full-load operation strategy is normally adopted. When the fan fails, there may be two situations of fan damage or stalling. A delay judgment link can be added. When the fault is further analyzed to be fan damage (that is, the fault signal cannot be eliminated within the delay time), the device enters the load limit mode and uses 70% of the full power to work. When the fault is further analyzed to be fan stalling (that is, the fault signal is eliminated within the delay time and maintained for a period of time without the fault signal appearing again), the device still uses full-load operation to ensure the efficient operation of the equipment.

[0055] Although the utility model is disclosed as above, the utility model is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the utility model. Therefore, the protection scope of the utility model shall be subject to the scope defined by the claims.

Claims

1. A fan monitoring system, characterized in that: It includes multiple high-pass filter modules, AND gate modules and state comparison modules; The multiple high-pass filter modules correspond one-to-one to the multiple fans, the input end of each high-pass filter module is respectively used to be connected to the feedback signal output end of the corresponding fan, the output ends of the multiple high-pass filter modules are all connected to the input end of the AND gate module, and the output end of the AND gate module is connected to the input end of the state comparison module.

2. The fan monitoring system according to claim 1, characterized in that: The high-pass filter module includes a clamped high-pass filter, the input end of the clamped high-pass filter serves as the input end of the high-pass filter module, and the output end of the clamped high-pass filter serves as the output end of the high-pass filter module.

3. The fan monitoring system according to claim 2, characterized in that: The clamped high-pass filter includes a first capacitor, a second capacitor, a first resistor, a second resistor, a third resistor, a first diode and a second diode. One end of the first capacitor serves as an input end of the clamped high-pass filter and is used to be connected to the feedback signal output end of the fan. One end of the first capacitor is also connected to one end of the second resistor. The other end of the second resistor is used to be connected to a first power supply. The other end of the first capacitor is respectively connected to the positive electrode of the second diode and the negative electrode of the first diode. The positive electrode of the first diode is grounded. The negative electrode of the second diode is connected to one end of the third resistor. The other end of the third resistor is respectively connected to one end of the first resistor and one end of the second capacitor. The other end of the first resistor and the other end of the second capacitor are grounded respectively. The other end of the third resistor serves as the output end of the clamped high-pass filter and is connected to the input end of the AND gate module.

4. The fan monitoring system according to claim 1, characterized in that: The AND gate module includes an AND gate circuit, which includes multiple circuit input terminals and circuit output terminals. The multiple circuit input terminals serve as multiple input terminals of the AND gate module and are connected one-to-one with the output terminals of the multiple high-pass filter modules; the circuit output terminal serves as the output terminal of the AND gate module and is connected to the input terminal of the state comparison module.

5. The fan monitoring system according to claim 4, characterized in that: The AND gate circuit includes multiple AND gate diodes and a fourth resistor. The cathodes of the multiple AND gate diodes serve as the multiple circuit input terminals of the AND gate circuit and are connected one-to-one with the output terminals of the multiple high-pass filtering modules. The anode of each AND gate diode is connected to one end of the fourth resistor, and the other end of the fourth resistor is used to be connected to the first power supply. The connection point formed by the anodes of each AND gate diode serves as the circuit output terminal of the AND gate circuit and is connected to the input terminal of the state comparison module.

6. The fan monitoring system according to claim 1, characterized in that: The AND gate module includes an AND gate chip, and the AND gate chip includes multiple input pins and output pins. The multiple input pins correspond to the output pins. The multiple input pins serve as multiple input ends of the AND gate module and are connected one-to-one with the output ends of the multiple high-pass filter modules; the output pins serve as the output end of the AND gate module and are connected to the input end of the state comparison module.

7. The fan monitoring system according to claim 1, characterized in that: The state comparison module includes a comparator, a fifth resistor, a seventh resistor, an eighth resistor, a third capacitor and a fourth capacitor; The inverting input end of the comparator serves as the input end of the state comparison module and is connected to the output end of the AND gate module; the non-inverting input end of the comparator is respectively connected to one end of the fifth resistor and one end of the third capacitor, the other end of the fifth resistor is used to be connected to a reference power supply, and the other end of the third capacitor is grounded; the output end of the comparator is respectively connected to one end of the seventh resistor and one end of the eighth resistor, the other end of the seventh resistor is used to be connected to a second power supply, the other end of the eighth resistor is connected to one end of the fourth capacitor, the other end of the fourth capacitor is grounded, and the other end of the eighth resistor also serves as the output end of the state comparison module.

8. The fan monitoring system according to claim 7, characterized in that: The state comparison module also includes a fourth diode and a sixth resistor, the anode of the fourth diode is connected to the non-inverting input terminal of the comparator, the cathode of the fourth diode is connected to one end of the sixth resistor, and the other end of the sixth resistor is connected to the output terminal of the comparator.

9. The fan monitoring system according to claim 1, characterized in that: The state comparison module comprises a NOT gate circuit, the input end of the NOT gate circuit serves as the input end of the state comparison module and is connected to the output end of the AND gate module; the output end of the NOT gate circuit serves as the output end of the state comparison module.

10. The fan monitoring system according to claim 1, characterized in that: It also includes a processing module, the input end of the processing module is connected to the output end of the state comparison module.

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