Fan failure detection board and fan failure detection device

Abstract

The application discloses a fan fault detection board and a fan fault detection device. The fan fault detection board comprises a detection unit, a control unit, a state feedback unit, a current limiting unit, a main power input interface, a main power output interface, a fan input interface, a fan output interface, a feedback power input interface, a feedback power output interface, a state feedback power interface and a state feedback output interface. The application can feed back the running state of the fan to the upper computer through the state feedback output interface, for example, normal working of the fan or fault of the fan, so that the detection of the fan fault is realized.

Description

Technical Field

[0001] This application relates to the field of power electronics technology, and in particular to a fan fault detection board and a fan fault detection device. Background Technology

[0002] In power electronic products, such as wind power converters, photovoltaic inverters, and energy storage converters, fans are essential for forced air cooling or water cooling. With the intensification of product cost competition, many products have replaced three-phase AC fans with fault detection with single-phase AC fans without fault detection or DC low-voltage fans. Furthermore, as the power level of products increases, the number of fans used in a single power electronic product increases, and the number of fan fault handling ports required increases accordingly. Utility Model Content

[0003] In view of this, the purpose of this application is to provide a fan fault detection board and a fan fault detection device, which can detect fan faults and is applicable to application scenarios of AC fans or DC fans, application scenarios of one or more fans, etc.

[0004] The technical solution adopted in this application to solve the above-mentioned technical problems is as follows:

[0005] According to one aspect of this application, a fan fault detection board is provided, including a detection unit, a control unit, a status feedback unit, a current limiting unit, a main power input interface, a main power output interface, a fan input interface, a fan output interface, a feedback power input interface, a feedback power output interface, a status feedback power interface, and a status feedback output interface.

[0006] The main power input interface and the main power output interface are connected to an external main power supply, the fan input interface and the fan output interface are connected to an external fan, and the fan output interface is short-circuited with the main power output interface; wherein, the fan has a built-in or external over-temperature protection unit;

[0007] The first input terminal of the detection unit is connected to the main power input interface, the second input terminal of the detection unit is connected to the fan input interface, the positive output terminal of the detection unit is connected to the positive input terminal of the control unit and the positive input terminal of the status feedback unit, the negative output terminal of the detection unit is connected to the negative input terminal of the control unit and the negative input terminal of the status feedback unit, the first output terminal of the status feedback unit is connected to the status feedback power interface, and the second output terminal of the status feedback unit is connected to the status feedback output interface; the feedback power input interface is connected to an external feedback power supply, and the status feedback output interface is connected to an external host computer.

[0008] One end of the current limiting unit is connected to the feedback power input interface, and the other end of the current limiting unit is connected to the feedback power output interface;

[0009] When the over-temperature protection unit is built into the fan, the feedback power output interface is short-circuited with the status feedback power interface; when the over-temperature protection unit is externally connected to the fan, one end of the over-temperature protection unit is connected to the feedback power output interface, and the other end of the over-temperature protection unit is connected to the status feedback power interface.

[0010] According to another aspect of this application, a fan fault detection device is provided, comprising a plurality of fan fault detection boards; each of the fan fault detection boards includes a detection unit, a control unit, a status feedback unit, a current limiting unit, a main power input interface, a main power output interface, a fan input interface, a fan output interface, a feedback power input interface, a feedback power output interface, a status feedback power interface, and a status feedback output interface.

[0011] The main power input interface and the main power output interface are connected to an external main power supply, the fan input interface and the fan output interface are connected to an external fan, and the fan output interface is short-circuited with the main power output interface;

[0012] The first input terminal of the detection unit is connected to the main power input interface, the second input terminal of the detection unit is connected to the fan input interface, the positive output terminal of the detection unit is connected to the positive input terminal of the control unit and the positive input terminal of the status feedback unit, the negative output terminal of the detection unit is connected to the negative input terminal of the control unit and the negative input terminal of the status feedback unit, the first output terminal of the status feedback unit is connected to the status feedback power interface, and the second output terminal of the status feedback unit is connected to the status feedback output interface.

[0013] One end of the current limiting unit is connected to the feedback power input interface, and the other end of the current limiting unit is connected to the feedback power output interface;

[0014] The first fan fault detection board has its feedback power input interface connected to an external feedback power supply, its feedback power output interface short-circuited to its status feedback power interface, its status feedback output interface connected to the status feedback power interface of the next fan fault detection board until the last fan fault detection board, and its status feedback output interface connected to an external host computer.

[0015] The fan fault detection board and fan fault detection device of this application embodiment can report the operating status of the fan to the host computer through the status feedback output interface, such as the fan working normally or the fan malfunctioning, thereby realizing the detection of fan faults. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of a fan fault detection board provided in an embodiment of this application;

[0017] Figure 2 A schematic diagram showing the fan fault detection board connected to the power supply and fan according to an embodiment of this application;

[0018] Figure 3 A circuit diagram of a fan fault detection board provided in an embodiment of this application;

[0019] Figure 4 Another circuit diagram of the fan fault detection board provided in the embodiments of this application;

[0020] Figure 5 Another circuit diagram of the fan fault detection board provided in the embodiments of this application;

[0021] Figure 6 This is a schematic diagram illustrating the application structure of multiple fan fault detection boards provided in the embodiments of this application.

[0022] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0023] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer and more understandable, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit the scope of this application.

[0024] like Figures 1-2 As shown, one embodiment of this application provides a fan fault detection board, including a detection unit, a control unit, a status feedback unit, a current limiting unit, a main power input interface Vin-L, a main power output interface Vout-L, a fan input interface Vin-F, a fan output interface Vout-F, a feedback power input interface Vp, a feedback power output interface TK1, a status feedback power interface TK2, and a status feedback output interface Vn.

[0025] The main power input interface Vin-L and the main power output interface Vout-L are connected to the external main power supply (shown in the input power supply in the figure). The fan input interface Vin-F and the fan output interface Vout-F are connected to the external fan. The fan output interface Vout-F is shorted to the main power output interface Vout-L. The fan has a built-in or external over-temperature protection unit.

[0026] The first input terminal of the detection unit (shown as 1 in the figure) is connected to the main power input interface Vin-L; the second input terminal of the detection unit (shown as 2 in the figure) is connected to the fan input interface Vin-F; the positive output terminal of the detection unit (shown as "+" in the figure) is connected to the positive input terminal of the control unit and the positive input terminal of the status feedback unit; the negative output terminal of the detection unit (shown as "-" in the figure) is connected to the negative input terminal of the control unit and the negative input terminal of the status feedback unit; the first output terminal of the status feedback unit is connected to the status feedback power interface TK2; the second output terminal of the status feedback unit is connected to the status feedback output interface Vn; the feedback power input interface Vp is connected to the external feedback power supply; and the status feedback output interface Vn is connected to the external host computer.

[0027] One end of the current limiting unit is connected to the feedback power input interface Vp, and the other end of the current limiting unit is connected to the feedback power output interface TK1.

[0028] When the over-temperature protection unit is built into the fan, the feedback power output interface TK1 and the status feedback power interface TK2 are shorted; when the over-temperature protection unit is connected externally to the fan, one end of the over-temperature protection unit is connected to the feedback power output interface TK1, and the other end of the over-temperature protection unit is connected to the status feedback power interface TK2.

[0029] In some examples, a protection unit is connected between the first input terminal of the detection unit and the main power input interface Vin-L, for example... Figures 3-5 The fuse FU1 shown includes a short-circuit protection fuse. This protection unit provides short-circuit protection in the event of a short circuit in the fan winding.

[0030] In some examples, the detection unit includes a diode rectifier bridge. For example... Figure 3As shown, the diode rectifier bridge includes diodes D1 to D4. The anode of diode D1 is connected to the anode of diode D3 to form the positive output of the detection unit. The cathode of diode D2 is connected to the cathode of diode D4 to form the negative output of the detection unit. The cathode of diode D1 is connected to the anode of diode D2 to form the first input terminal of the detection unit (as shown in a in the figure). The cathode of diode D3 is connected to the anode of diode D4 to form the second input terminal of the detection unit (as shown in b in the figure).

[0031] In some examples, the detection unit includes a first shorting switch and a second shorting switch, one end of the first shorting switch being a first input terminal of the detection unit, one end of the second shorting switch being a second input terminal of the detection unit, the other end of the first shorting switch being the positive output terminal of the detection unit, and the other end of the second shorting switch being the negative output terminal of the detection unit.

[0032] For example Figure 4 As shown, one end (left side) of the first shorting switch JP1 is the first input terminal of the detection unit, one end (left side) of the second shorting switch JP2 is the second input terminal of the detection unit, the other end (right side) of the first shorting switch JP1 is the positive output terminal of the detection unit, and the other end (right side) of the second shorting switch JP2 is the negative output terminal of the detection unit.

[0033] Compared to Figure 3 The detection unit shown, Figure 4 The detection unit can save costs.

[0034] In some examples, the detection unit includes a Hall sensor, with the positive input of the Hall sensor being a first input terminal of the detection unit, the negative input of the Hall sensor being a second input terminal of the detection unit, the output port of the Hall sensor being the positive output terminal of the detection unit, and the ground interface of the Hall sensor being the negative output terminal of the detection unit. The Hall sensor also includes a power interface connected to the feedback power supply.

[0035] For example Figure 5As shown, the positive input terminal of Hall sensor CT1 (the end on the left connected to fuse FU1) is the first input terminal of the detection unit, the negative input terminal of Hall sensor CT1 (the end on the left connected to the fan input interface Vin-F) is the second input terminal of the detection unit, the output port of Hall sensor CT1 (the end on the right connected to resistors R1 and R6) is the positive output terminal of the detection unit, and the ground interface of the Hall sensor (the end on the bottom connected to resistors R1, R5, and capacitor C1) is the negative output terminal of the detection unit. The power interface of Hall sensor CT1 (the end on the top connected to the feedback power supply VCC) is connected to the feedback power supply.

[0036] In some examples, the control unit includes a plurality of diodes connected in series, with the anode of the series-connected diodes serving as the positive input terminal of the control unit and the cathode of the series-connected diodes serving as the negative input terminal of the control unit.

[0037] For example Figure 3 or Figure 4 As shown, the control unit includes diodes D5-D8 connected in series. The anode of diode D5 is the positive input terminal of the control unit. The cathode of diode D5 is connected to the anode of diode D6. The cathode of diode D6 is connected to the anode of diode D7. The cathode of diode D7 is connected to the anode of diode D8. The cathode of diode D8 is the negative input terminal of the control unit.

[0038] In some examples, the control unit includes a first current-limiting resistor. For example, as shown below... Figure 5 As shown, the control unit includes a current-limiting resistor R6, one end of which is the positive input terminal of the control unit, and the other end of which is the negative input terminal of the control unit.

[0039] In some examples, the state feedback unit includes an optocoupler isolation module. The first terminal of the optocoupler isolation module is connected to the positive output of the detection unit through a second current-limiting resistor. The second terminal of the optocoupler isolation module is connected to the negative output of the detection unit. A first filter capacitor is connected between the first and second terminals of the optocoupler isolation module. The third terminal of the optocoupler isolation module is connected to the state feedback power interface TK2. The fourth terminal of the optocoupler isolation module is connected to the state feedback output interface Vn.

[0040] For example Figure 3As shown, the first terminal of the optocoupler isolation module U1 (shown as 1 in the figure) is connected to the positive output of the detection unit through a current-limiting resistor R1. The second terminal of the optocoupler isolation module U1 (shown as 2 in the figure) is connected to the negative output of the detection unit. A filter capacitor C1 is connected between the first terminal and the second terminal of the optocoupler isolation module U1. The third terminal of the optocoupler isolation module U1 (shown as 3 in the figure) is connected to the status feedback power interface TK2. The fourth terminal of the optocoupler isolation module U1 (shown as 4 in the figure) is connected to the status feedback output interface Vn.

[0041] The optocoupler isolation module U1 is a device used for isolating and transmitting electrical signals, consisting of a light-emitting diode and a phototransistor or phototransistor.

[0042] In some examples, the state feedback unit includes a transistor, a third current-limiting resistor, and a second filter capacitor;

[0043] The base of the transistor is connected to one end of the third current-limiting resistor and one end of the second filter capacitor. The other end of the third current-limiting resistor is connected to the positive output of the detection unit. The other end of the second filter capacitor is connected to the negative output of the detection unit. The collector of the transistor is connected to the state feedback power interface TK2. The emitter of the transistor is connected to the state feedback output interface Vn.

[0044] For example Figure 4 or Figure 5 As shown, the base of transistor Q1 is connected to one end of current-limiting resistor R1 and one end of filter capacitor C1 through driving resistor R4. The other end of current-limiting resistor R1 is connected to the positive output of the detection unit, and the other end of filter capacitor C1 is connected to the negative output of the detection unit. The base of transistor Q1 is also connected to the negative output of the detection unit through protection resistor R5. The collector of transistor Q1 is connected to the state feedback power interface TK2, and the emitter of transistor Q1 is connected to the state feedback output interface Vn.

[0045] Compared to Figure 3 The state feedback unit shown is Figure 4 The status feedback unit can save board space and cost.

[0046] In some examples, the current limiting unit includes a current limiting resistor, for example... Figures 3-5 The current-limiting resistor R2 shown has one end connected to the feedback power input interface Vp and the other end connected to the feedback power output interface TK1. The feedback power input interface Vp is connected to the feedback power VCC.

[0047] The output level of the status feedback output interface Vn is determined by the magnitude of the feedback power supply VCC. However... Figure 3 In the example, the voltage amplitude of the feedback power supply VCC is limited by the withstand voltage of the optocoupler isolation module U1 and by the input level voltage of the host computer detection port. In wind power converters, the voltage of the feedback power supply VCC is typically 15VDC or 24VDC. Figure 4 In the example, the feedback power supply VCC can be the same as the positive output of the detection unit, that is, the feedback power supply VCC is connected to the positive output of the detection unit. Figure 5 In the example, the feedback power supply VCC is connected to the power interface of the Hall sensor CT1.

[0048] It should be noted that, for Figure 3 The circuit shown can be applied to power electronic products, such as single-phase AC fans with over-temperature protection function in a specific power range of less than 300W commonly used in wind power converter products. It can also distinguish between two types of fan hardware configurations, such as those with built-in over-temperature protection switches and those with external over-temperature protection switches.

[0049] It should be noted that, for Figure 3 The circuit shown is suitable for AC fans, with the external main power supply (input power supply shown in the diagram) being a single-phase AC power supply. For Figure 4 The circuit shown is suitable for DC fans, with an external main power supply (input power supply shown in the diagram) that is a low-voltage DC power supply. Figure 5 The circuit shown is suitable for DC fans or AC fans.

[0050] It should be noted that the host computer includes the control system of power electronic products, such as the control system of a wind power converter. When the host computer receives a fan fault feedback signal, it will issue a fan fault alarm or shutdown maintenance command based on the specific operating conditions to ensure that the heat-dissipated components are within a safe temperature range.

[0051] It should be noted that the fan fault detection board feeds back the fan's operating status signal to the host computer. The specific fault level is determined by the host computer's detection port circuit, which facilitates flexible configuration of the host computer and saves resources. When the fan stalls and over-temperatures, the output level of the fan fault detection board reliably reverses, and the fault status is fed back to the host computer for accurate identification, making detection efficient and reliable.

[0052] During implementation, when the fan is working normally, the main power supply current flows into the detection unit, and the output of the detection unit flows into the control unit. The control unit controls the status feedback unit to work, and the status feedback unit outputs a working status level to the host computer. When the fan malfunctions, the fan windings heat up, and the fan winding temperature rises to the over-temperature protection switch's activation value. The over-temperature protection switch disconnects the fan power supply, the fan power supply current is zero, the control unit cannot control the status feedback unit to work, and the status feedback unit outputs a fault status level.

[0053] by Figure 3 For example, when the fan is running normally, diodes D5, D6, D7, and D8 are conducting. The forward voltage of these four series-connected diodes drives the optocoupler isolation module U1 to work. The optocoupler isolation module U1 outputs a normal status level through the status feedback output interface Vn. When the fan malfunctions, diodes D5, D6, D7, and D8 are not conducting. The series-connected diodes have no forward voltage, the optocoupler isolation module U1 does not work, and the status feedback interface Vn outputs a fault status level.

[0054] by Figure 4 For example, when the fan is working normally, the main power supply current flows through shorting switch JP1, then through diodes D5-D8 connected in series, then through shorting switch JP2, and finally into the fan. The current forms a conduction voltage across diodes D5-D8. This conduction voltage is processed by resistors R1, capacitor C1, resistor R4, and resistor R5, and outputs as the turn-on voltage for transistor Q1. The emitter of transistor Q1 outputs a normal operating status level to the host computer through the status feedback interface Vn. When the fan malfunctions, there is no voltage across diodes D5-D8. Therefore, no voltage is processed by resistors R1, capacitor C1, resistor R4, and resistor R5, and transistor Q1 has no driving voltage. Transistor Q1 is turned off, and its emitter outputs a fault status level to the host computer through the status feedback interface Vn.

[0055] by Figure 5 For example, when the fan is working normally, the CT1 Hall sensor outputs a continuous signal, and the voltage across resistor R6 is continuous and greater than zero. This voltage is processed through resistor R1, capacitor C1, resistor R4, and resistor R5, and outputs the turn-on voltage of transistor Q1. The emitter of transistor Q1 outputs a normal operating state level to the host computer. When the fan malfunctions, the CT1 Hall sensor outputs a zero signal, and the voltage across resistor R6 is zero. There is no voltage processed through resistor R1, capacitor C1, resistor R4, and resistor R5. Transistor Q1 has no driving voltage, so it is turned off, and the emitter of transistor Q1 outputs a fault state level to the host computer.

[0056] like Figure 6 As shown, another embodiment of this application provides a fan fault device, including multiple fan fault detection boards; each of the fan fault detection boards includes a detection unit, a control unit, a status feedback unit, a current limiting unit, a main power input interface Vin-L, a main power output interface Vout-L, a fan input interface Vin-F, a fan output interface Vout-F, a feedback power input interface Vp, a feedback power output interface TK1, a status feedback power interface TK2, and a status feedback output interface Vn;

[0057] The main power input interface Vin-L and the main power output interface Vout-L are connected to the external main power supply (for example, as shown in the figure, input power supply 1 to input power supply n, which can be different power supplies or the same power supply). The fan input interface Vin-F and the fan output interface Vout-F are connected to the external fan (for example, as shown in the figure, fan 1 to fan n). The fan output interface Vout-F is shorted to the main power output interface Vout-L.

[0058] The first input terminal of the detection unit is connected to the main power input interface Vin-L, the second input terminal of the detection unit is connected to the fan input interface Vin-F, the positive output terminal of the detection unit is connected to the positive input terminal of the control unit and the positive input terminal of the status feedback unit, the negative output terminal of the detection unit is connected to the negative input terminal of the control unit and the negative input terminal of the status feedback unit, the first output terminal of the status feedback unit is connected to the status feedback power interface TK2, and the second output terminal of the status feedback unit is connected to the status feedback output interface Vn.

[0059] One end of the current limiting unit is connected to the feedback power input interface Vp, and the other end of the current limiting unit is connected to the feedback power output interface TK1.

[0060] The first fan fault detection board has its feedback power input interface Vp connected to an external feedback power supply. The feedback power output interface TK1 of the first fan fault detection board is shorted to the status feedback power interface TK2 of the first fan fault detection board. The status feedback output interface Vn of the first fan fault detection board is connected to the status feedback power interface TK2 of the next fan fault detection board until the last fan fault detection board. The status feedback output interface Vn of the last fan fault detection board is connected to an external host computer.

[0061] It should be noted that, in Figure 6 In the example, with Figures 1-5 For examples of the same components, please refer to the preceding sections.

[0062] exist Figure 6 In the example, in order to reduce the occupation of the host computer's fault processing port resources, when the heat-dissipated device has a high power consumption and needs to be equipped with multiple fans for heat dissipation, the fan fault detection output of each fan can be connected in series through the output status interface. Only one operating status interface is output. If any of the multiple fans fails, the output operating status level will change to the fault status level. When the host computer detects the fault status level, it will process it according to the fault logic.

[0063] Specifically, the operating status of N fans is connected in series via an interface, and a general operating status signal is output and fed back to the host computer. If any of the N fans experiences a stall, over-temperature protection failure, or wire breakage, the operating status signal will output a fault level and feed it back to the host computer. If all N fans are operating normally, the operating status signal will output a normal status to the host computer.

[0064] exist Figure 6 In the example, open-circuit protection can be provided. When the power supply or fan port wiring is broken, the protection logic is consistent with the fault protection logic. It can also integrate multiple detection circuits onto a single detection board to simultaneously detect the operating status of multiple fans, improving detection efficiency, saving structural space, and reducing overall detection costs.

[0065] The preferred embodiments of this application have been described above with reference to the accompanying drawings, but this does not limit the scope of the application. Those skilled in the art can implement this application in various modifications without departing from its scope and spirit; for example, a feature of one embodiment can be used in another embodiment to obtain yet another embodiment. Any modifications, equivalent substitutions, and improvements made within the scope of the technical concept of this application should be within the scope of the application.

Claims

1. A fan fault detection board, characterized in that, It includes a detection unit, a control unit, a status feedback unit, a current limiting unit, a main power input interface, a main power output interface, a fan input interface, a fan output interface, a feedback power input interface, a feedback power output interface, a status feedback power interface, and a status feedback output interface. The main power input interface and the main power output interface are connected to an external main power supply, the fan input interface and the fan output interface are connected to an external fan, and the fan output interface is short-circuited with the main power output interface; wherein, the fan has a built-in or external over-temperature protection unit; The first input terminal of the detection unit is connected to the main power input interface, the second input terminal of the detection unit is connected to the fan input interface, the positive output terminal of the detection unit is connected to the positive input terminal of the control unit and the positive input terminal of the status feedback unit, the negative output terminal of the detection unit is connected to the negative input terminal of the control unit and the negative input terminal of the status feedback unit, the first output terminal of the status feedback unit is connected to the status feedback power interface, and the second output terminal of the status feedback unit is connected to the status feedback output interface; the feedback power input interface is connected to an external feedback power supply, and the status feedback output interface is connected to an external host computer. One end of the current limiting unit is connected to the feedback power input interface, and the other end of the current limiting unit is connected to the feedback power output interface; When the over-temperature protection unit is built into the fan, the feedback power output interface is short-circuited with the status feedback power interface; when the over-temperature protection unit is externally connected to the fan, one end of the over-temperature protection unit is connected to the feedback power output interface, and the other end of the over-temperature protection unit is connected to the status feedback power interface.

2. The fan fault detection board according to claim 1, characterized in that, The detection unit includes a diode rectifier bridge.

3. The fan fault detection board according to claim 1, characterized in that, The detection unit includes a first shorting switch and a second shorting switch. One end of the first shorting switch is the first input terminal of the detection unit, and one end of the second shorting switch is the second input terminal of the detection unit. The other end of the first shorting switch is the positive output terminal of the detection unit, and the other end of the second shorting switch is the negative output terminal of the detection unit.

4. The fan fault detection board according to claim 1, characterized in that, The detection unit includes a Hall sensor, the positive input of which is the first input terminal of the detection unit, the negative input of which is the second input terminal of the detection unit, the output port of which is the positive output terminal of the detection unit, and the ground interface of which is the negative output terminal of the detection unit.

5. The fan fault detection board according to claim 4, characterized in that, The Hall sensor also includes a power interface, which is connected to the feedback power supply.

6. The fan fault detection board according to claim 1, characterized in that, The control unit includes a plurality of diodes connected in series, wherein the anode of the plurality of diodes connected in series is the positive input terminal of the control unit, and the cathode of the plurality of diodes connected in series is the negative input terminal of the control unit; or, the control unit includes a first current-limiting resistor.

7. The fan fault detection board according to claim 1, characterized in that, The status feedback unit includes an optocoupler isolation module. The first end of the optocoupler isolation module is connected to the positive output of the detection unit through a second current-limiting resistor. The second end of the optocoupler isolation module is connected to the negative output of the detection unit. A first filter capacitor is connected between the first end and the second end of the optocoupler isolation module. The third end of the optocoupler isolation module is connected to the status feedback power interface. The fourth end of the optocoupler isolation module is connected to the status feedback output interface.

8. The fan fault detection board according to claim 1, characterized in that, The status feedback unit includes a transistor, a third current-limiting resistor, and a second filter capacitor. The base of the transistor is connected to one end of the third current-limiting resistor and one end of the second filter capacitor. The other end of the third current-limiting resistor is connected to the positive output of the detection unit. The other end of the second filter capacitor is connected to the negative output of the detection unit. The collector of the transistor is connected to the state feedback power interface. The emitter of the transistor is connected to the state feedback output interface.

9. The fan fault detection board according to claim 1, characterized in that, A protection unit is connected between the first input terminal of the detection unit and the main power input interface.

10. A fan fault detection device, characterized in that, It includes multiple fan fault detection boards; each of the fan fault detection boards includes a detection unit, a control unit, a status feedback unit, a current limiting unit, a main power input interface, a main power output interface, a fan input interface, a fan output interface, a feedback power input interface, a feedback power output interface, a status feedback power interface, and a status feedback output interface. The main power input interface and the main power output interface are connected to an external main power supply, the fan input interface and the fan output interface are connected to an external fan, and the fan output interface is short-circuited with the main power output interface; The first input terminal of the detection unit is connected to the main power input interface, the second input terminal of the detection unit is connected to the fan input interface, the positive output terminal of the detection unit is connected to the positive input terminal of the control unit and the positive input terminal of the status feedback unit, the negative output terminal of the detection unit is connected to the negative input terminal of the control unit and the negative input terminal of the status feedback unit, the first output terminal of the status feedback unit is connected to the status feedback power interface, and the second output terminal of the status feedback unit is connected to the status feedback output interface. One end of the current limiting unit is connected to the feedback power input interface, and the other end of the current limiting unit is connected to the feedback power output interface; The first fan fault detection board has its feedback power input interface connected to an external feedback power supply, its feedback power output interface short-circuited to its status feedback power interface, its status feedback output interface connected to the status feedback power interface of the next fan fault detection board until the last fan fault detection board, and its status feedback output interface connected to an external host computer.

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