Control Circuit of Cooling Fan, Its Control Method, and Cooling Fan Control System

Abstract

The present invention discloses a control circuit for a cooling fan, a control method thereof, and a cooling fan control system. By adding an open-circuit detection module and an overcurrent / short-circuit detection module to the drive circuit of the cooling fan, open-circuit detection and overcurrent / short-circuit detection are performed on the cooling fan module. When the control system of the electric control box is working, overcurrent, short-circuit, and open-circuit detection of the cooling fan are carried out in real time to monitor the operating state of the cooling fan in real time. If the cooling fan is open-circuited, overcurrent / short-circuited, the start and stop of the cooling fan can be reasonably controlled to protect the cooling fan and prevent it from being burned out due to overcurrent or open circuit, ensuring the heat dissipation of the electric control box.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical field of kitchen appliances, and in particular, to a control circuit for a cooling fan, a control method therefor, and a cooling fan control system. Background Art

[0002] As the importance of environmental protection becomes increasingly high, the current external exhaust type of range hoods in the kitchen has a great impact on the environment. Therefore, a central range hood has been introduced in the industry, which filters and purifies the oil fumes in the common flue and then discharges them. In this case, the main fan on the roof requires an electric control box system. However, since most of the electric control boxes are placed on the roof all year round, especially in the hot summer, the temperature on the roof will exceed 40 degrees Celsius. Moreover, the controller components such as the frequency converter for controlling the main fan in the electric control box system generate a large amount of heat. Therefore, a cooling fan is installed in the electric control box to discharge the excess heat energy from the electric control box, so as to cool the inside of the electric control box, enabling the frequency conversion controller and related controller components in the electric control box to work in a reasonable temperature environment and preventing device damage.

[0003] Currently, most of the electric control boxes on the market are equipped with AC or DC cooling fans, which only perform simple on-off control and cannot protect the cooling fan, that is, they cannot detect the overcurrent, short-circuit, and open-circuit states of the cooling fan in real time. If the cooling fan is damaged, it cannot dissipate heat from the electric control box, and it is very easy for the control system of the main fan to stop working due to overheat protection or burnout of the control system. Summary of the Invention

[0004] In view of this, the embodiments of the present invention provide a control circuit for a cooling fan, a control method therefor, and a cooling fan control system. When the control system of the electric control box of the fan works, the cooling fan of the electric control box is turned on simultaneously, and real-time overcurrent, short-circuit, and open-circuit detection of the cooling fan is performed. If the cooling fan is overcurrent, appropriate protection can be carried out to avoid burning out the cooling fan.

[0005] In a first aspect, the embodiments of the present invention provide a control circuit for a cooling fan, including a main control module, a fan driving module, an open-circuit detection module, an overcurrent / short-circuit detection module, and a cooling fan module.

[0006] The main control module is electrically connected to the fan driving module, the open-circuit detection module, and the overcurrent / short-circuit detection module respectively. The cooling fan module is electrically connected to the fan driving module and the open-circuit detection module respectively. The fan driving module is also electrically connected to the overcurrent / short-circuit detection module and is connected in parallel with the open-circuit detection module.

[0007] The main control module includes a drive signal output terminal, an open circuit detection signal receiving terminal, and an overcurrent / short circuit detection signal receiving terminal; the fan drive module includes a drive signal receiving terminal, the overcurrent / short circuit detection module includes an overcurrent / short circuit detection signal output terminal, and the open circuit detection module includes an open circuit detection signal output terminal; the drive signal output terminal is electrically connected to the drive signal receiving terminal for transmitting a drive signal; the overcurrent / short circuit detection signal output terminal and the overcurrent / short circuit detection signal receiving terminal are electrically connected for transmitting an overcurrent / short circuit detection signal; the open circuit detection signal output terminal is electrically connected to the open circuit detection signal receiving terminal for transmitting an open circuit detection signal;

[0008] The main control module is configured to determine the connection state of the cooling fan module according to the open circuit detection signal; the connection state includes a path and an open circuit; the main control module is further configured to output the drive signal according to the connection state, and the fan drive module is configured to control the operating state of the cooling fan module according to the drive signal; the operating state further includes on and off;

[0009] The main control module is further configured to control the operating state of the cooling fan module according to the overcurrent / short circuit detection signal.

[0010] Optionally, the cooling fan module includes a positive output terminal, a negative output terminal, and a first diode; the fan drive module includes a first resistor, a second resistor, a third resistor, a fourth resistor, a first drive transistor, and a drive switch unit; the open circuit detection module includes a fifth resistor, a sixth resistor, and a voltage stabilizing unit, and the overcurrent / short circuit detection module includes an eighth resistor, a ninth resistor, a tenth resistor, an eleventh resistor, a third drive transistor, a first capacitor, and a second capacitor,

[0011] The negative electrode of the first diode is electrically connected to the positive output terminal of the cooling fan module, and the positive electrode of the first diode is grounded; the first end of the first resistor is electrically connected to the drive signal output terminal, the second end of the first resistor is respectively electrically connected to the first end of the second resistor and the first end of the first drive transistor, the first end of the third resistor is respectively electrically connected to the second end of the first drive transistor, the second end of the third resistor is respectively electrically connected to the first end of the drive switch unit and the first end of the fourth resistor, and the third end of the first drive transistor is grounded;

[0012] The third terminal of the driving switch unit is electrically connected to the first terminal of the sixth resistor, the first terminal of the eighth resistor, and the first terminal of the ninth resistor respectively; the second terminal of the driving switch unit is electrically connected to the first terminal of the fifth resistor, the second terminal of the sixth resistor, and the positive output terminal of the cooling fan module respectively; the second terminal of the fifth resistor is electrically connected to the negative output terminal of the voltage stabilizing unit and the open circuit detection signal receiving terminal respectively; the positive input terminal of the voltage stabilizing unit is grounded; the negative output terminal of the cooling fan module is grounded;

[0013] The second terminal of the eighth resistor is electrically connected to the first terminal of the third driving transistor and the first terminal of the second capacitor respectively. The second terminal of the third driving transistor, the second terminal of the second capacitor, and the second terminal of the ninth resistor are all electrically connected to the first power supply. The first terminal of the eleventh resistor is electrically connected to the third terminal of the third driving transistor. The second terminal of the eleventh resistor is electrically connected to the first terminal of the tenth resistor, the first terminal of the first capacitor, and the overcurrent / short circuit detection signal receiving terminal respectively. The second terminal of the tenth resistor and the second terminal of the first capacitor are grounded.

[0014] Optionally, the driving switch unit includes a fourth resistor and a second driving transistor;

[0015] The second terminal of the third resistor is electrically connected to the first terminal of the second driving transistor and the first terminal of the fourth resistor respectively;

[0016] The second terminal of the second driving transistor is electrically connected to the first terminal of the fifth resistor, the second terminal of the sixth resistor, and the positive output terminal of the cooling fan module respectively;

[0017] The third terminal of the second driving transistor is electrically connected to the second terminal of the fourth resistor, the first terminal of the sixth resistor, the first terminal of the eighth resistor, and the first terminal of the ninth resistor respectively.

[0018] Optionally, the driving switch unit includes a third diode and a relay;

[0019] The second terminal of the first driving transistor is electrically connected to the first terminal of the relay and the positive electrode of the third diode respectively. The fifth terminal of the relay and the negative electrode of the third diode are electrically connected to the first power supply respectively. The third terminal of the first driving transistor is grounded;

[0020] The second terminal of the relay is electrically connected to the first terminal of the fifth resistor, the second terminal of the sixth resistor, and the positive output terminal of the cooling fan module respectively;

[0021] The third terminal of the relay is electrically connected to the first terminal of the sixth resistor, the first terminal of the eighth resistor, and the first terminal of the ninth resistor respectively;

[0022] The relay includes a switching switch, which can be connected to the third terminal of the relay or the fourth terminal of the relay; the fourth terminal of the relay is in neutral.

[0023] Optionally, the voltage stabilizing unit includes a voltage stabilizing diode;

[0024] The negative electrode of the voltage stabilizing diode is electrically connected to the second terminal of the fifth resistor and the open circuit detection signal receiving terminal respectively; the positive electrode of the voltage stabilizing diode is grounded.

[0025] Optionally, the voltage stabilizing unit includes a second diode;

[0026] The positive electrode of the second diode is electrically connected to the second terminal of the fifth resistor and the open circuit detection signal receiving terminal respectively; the negative electrode of the second diode is electrically connected to a second power supply;

[0027] Wherein, the voltage of the second power supply is lower than the voltage of the first power supply.

[0028] Optionally, the control circuit further includes an alarm module, and the alarm module is connected to the main control module;

[0029] The main control module is further configured to output an alarm signal according to the open circuit detection signal and / or the overcurrent / short circuit detection signal, and the alarm module issues an alarm prompt according to the alarm signal.

[0030] Optionally, the control circuit further includes a cloud, and the cloud is communicatively connected to the main control module;

[0031] The main control module is further configured to upload the operating state of the cooling fan module and the alarm prompt to the cloud.

[0032] In a second aspect, an embodiment of the present invention further provides a control method for a cooling fan, which is used to control any one of the control circuits of the cooling fan provided in the first aspect. The control method includes:

[0033] Receiving the open circuit detection signal, and determining the connection state of the cooling fan module according to the open circuit detection signal; the connection state includes a path and an open circuit;

[0034] According to the connection state, output the drive signal to the fan drive module, so that the fan drive module controls the operating state of the cooling fan module according to the drive signal; the operating state includes on and off;

[0035] Receive the overcurrent / short-circuit detection signal and control the operating state of the heat dissipation fan module according to the overcurrent / short-circuit detection signal.

[0036] Optionally, the open-circuit detection signal includes a first potential signal and a second potential signal, the amplitude of the first potential signal is less than that of the second potential signal, and the connection state includes a path and an open circuit;

[0037] Receive the open-circuit detection signal and determine the connection state of the heat dissipation fan module according to the open-circuit detection signal, including:

[0038] Receive the open-circuit detection signal;

[0039] When the open-circuit detection signal is the first potential signal, determine that the connection state of the heat dissipation fan module is a path;

[0040] When the open-circuit detection signal is the second potential signal, determine that the connection state of the heat dissipation fan module is an open circuit.

[0041] Optionally, the drive signal includes a first level signal and a second level signal, the amplitude of the first level signal is greater than that of the second level signal, the connection state includes a path, the operating state further includes start and stop, and the heat dissipation fan module includes a heat dissipation fan;

[0042] According to the connection state, output the drive signal to the fan drive module so that the fan drive module controls the operating state of the heat dissipation fan module according to the drive signal, including:

[0043] When the connection state of the heat dissipation fan module is a path, output the first level signal to the fan drive module so that the fan drive module controls the heat dissipation fan to start according to the first level signal;

[0044] Or, when the connection state of the heat dissipation fan module is a path, output the second level signal to the fan drive module so that the fan drive module controls the heat dissipation fan to stop rotating according to the second level signal.

[0045] Optionally, according to the connection state, output the drive signal to the fan drive module so that the fan drive module controls the operating state of the heat dissipation fan module according to the drive signal, including:

[0046] When the connection state of the heat dissipation fan module is a path, alternately output the first level signal and the second level signal to the fan drive module so that the fan drive module controls the operating speed of the heat dissipation fan according to the first level signal and the second level signal.

[0047] Optionally, the duration of the first level signal and the duration of the second level signal are different.

[0048] Optionally, while alternately outputting the first level signal and the second level signal to the fan drive module to enable the fan drive module to control the operating speed of the cooling fan according to the first level signal and the second level signal, the control method further includes:

[0049] While the fan drive module controls the cooling fan to turn off according to the second level signal, receive the open circuit detection signal, and determine the connection state of the cooling fan module according to the open circuit detection signal.

[0050] In a third aspect, an embodiment of the present invention provides a cooling fan control system, including any one of the control circuits of the cooling fans provided in the first aspect.

[0051] The control circuit of the cooling fan provided by the embodiment of the present invention adds an open circuit detection module and an overcurrent / short circuit detection module to the drive circuit of the cooling fan to perform open circuit detection and overcurrent / short circuit detection on the cooling fan module. When the electric control box control system is working, it performs real-time overcurrent, short circuit, and open circuit detection on the cooling fan to monitor the operating state of the cooling fan in real time. If the cooling fan is open circuit, overcurrent / short circuit, it can reasonably control the start and stop of the cooling fan to protect the cooling fan and prevent it from being burned out due to overcurrent or open circuit, ensuring the heat dissipation of the electric control box. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Other features, objects, and advantages of the present invention will become more apparent by reading the detailed description of the non-limiting embodiments with reference to the following drawings:

[0053] Figure 1 It is a schematic diagram of the modules of a control circuit of a cooling fan provided by an embodiment of the present invention;

[0054] Figure 2 It is a schematic diagram of the control signal logic of a cooling fan provided by an embodiment of the present invention;

[0055] Figure 3 It is a control circuit diagram of a cooling fan provided by an embodiment of the present invention;

[0056] Figure 4 It is another control circuit diagram of a cooling fan provided by an embodiment of the present invention;

[0057] Figure 5 It is a flowchart of a control method of a cooling fan provided by an embodiment of the present invention;

[0058] Figure 6Flowchart of another control method for the cooling fan provided by the embodiment of the present invention;

[0059] Figure 7 Schematic diagram of the control logic of a control circuit for a cooling fan provided by the embodiment of the present invention. Detailed implementation manners

[0060] To make the objectives, technical solutions and advantages of the present invention clearer, the following will describe the technical solutions of the present invention completely through specific implementation manners in combination with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0061] Embodiment

[0062] The embodiment of the present invention provides a control circuit for a cooling fan, which can be used to control the start and stop of the cooling fan of the main engine electric control box in the central oil fume purification system. Figure 1 Module schematic diagram of a control circuit for a cooling fan provided by the embodiment of the present invention; Figure 2 Schematic diagram of the control signal logic of a cooling fan provided by the embodiment of the present invention; Figure 3 Circuit diagram of a control circuit for a cooling fan provided by the embodiment of the present invention; Figure 4 Another circuit diagram of a control circuit for a cooling fan provided by the embodiment of the present invention. As Figures 1-4As shown in the figure, a control circuit for a cooling fan provided by an embodiment of the present invention includes a main control module 1, a fan drive module 2, an open circuit detection module 3, an overcurrent / short circuit detection module 4, and a cooling fan module 5. The main control module 1 is electrically connected to the fan drive module 2, the open circuit detection module 3, and the overcurrent / short circuit detection module 4 respectively. The cooling fan module 5 is electrically connected to the fan drive module 2 and the open circuit detection module 3 respectively. The fan drive module 2 is also electrically connected to the overcurrent / short circuit detection module 4 and is connected in parallel with the open circuit detection module 3. The main control module 1 includes an open circuit detection signal receiving end 11, a drive signal output end 12, and an overcurrent / short circuit detection signal receiving end 13. The fan drive module 2 includes a drive signal receiving end 21. The overcurrent / short circuit detection module 4 includes an overcurrent / short circuit detection signal output end 41. The open circuit detection module 3 includes an open circuit detection signal output end 31. The drive signal output end 12 is electrically connected to the drive signal receiving end 21 for transmitting a drive signal. The overcurrent / short circuit detection signal output end 41 is electrically connected to the overcurrent / short circuit detection signal receiving end 13 for transmitting an overcurrent / short circuit detection signal. The open circuit detection signal output end 31 is electrically connected to the open circuit detection signal receiving end 11 for transmitting an open circuit detection signal. The main control module 1 is configured to determine the connection state of the cooling fan module 5 according to the open circuit detection signal. The connection state includes a path and an open circuit. The main control module 1 is further configured to output a drive signal according to the connection state. The fan drive module 2 is configured to control the operating state of the cooling fan module 5 according to the drive signal. The operating state further includes on and off. The main control module 1 is further configured to control the operating state of the cooling fan module 5 according to the overcurrent / short circuit detection signal.

[0063] Specifically, the control circuit of the cooling fan includes a main control module 1. The main control module 1 is the main control system of the cooling fan control system and is used to control the operation of the control circuit of the cooling fan. The main control module 1 is electrically connected to the fan drive module 2, the open circuit detection module 3, and the overcurrent / short circuit detection module 4 respectively. The cooling fan module 5 is electrically connected to the fan drive module 2 and the open circuit detection module 3 respectively.

[0064] The cooling fan module 5 includes a cooling fan, a fan plug CN2, and a fan socket CN1. Among them, the connection state of the cooling fan module 5 includes a path and an open circuit. When the fan plug CN2 and the fan socket CN1 are electrically connected, it indicates that the connection state of the cooling fan module is a path and the cooling fan is in a standby state. When the fan plug CN2 and the fan socket CN1 are disconnected, it indicates that the connection state of the cooling fan module is an open circuit and the cooling fan cannot work properly.

[0065] After the main control module 1 in the control system is powered on by connecting the 5V working voltage through the VDD terminal, the open-circuit detection module 3 continuously detects whether the fan plug of the cooling fan is inserted into the fan socket and generates an open-circuit detection signal, which is output from the open-circuit detection signal output terminal 31 to the open-circuit detection signal receiving terminal 11 of the main control module 1. The main control module 1 analyzes and determines the connection status of the cooling fan module 5 based on the open-circuit detection signal. When the cooling fan is open-circuited, it prompts the main control module 1 that a fault repair is required. Among them, the open-circuit detection signal includes a high level and a low level; the fan drive module 2 is also electrically connected to the overcurrent / short-circuit detection module 4 and is in parallel with the open-circuit detection module 3 to ensure that the fan drive module 2 and the open-circuit detection module 3 cannot work simultaneously. The fan drive module 2 is used to control the operating state of the cooling fan in the cooling fan module 5. Among them, the operating state includes start and stop; the overcurrent / short-circuit detection module 4 is used to detect the overcurrent / short-circuit detection signal of the cooling fan in the cooling fan module 5 and outputs the overcurrent / short-circuit detection signal from the overcurrent / short-circuit detection signal output terminal 41 to the overcurrent / short-circuit detection signal receiving terminal 13 of the main control module 1. The main control module 1 analyzes and determines the operating state of the cooling fan module 5 based on the overcurrent / short-circuit detection signal. When the cooling fan is overcurrent / short-circuited, it controls the cooling fan to stop rotating to protect the cooling fan. Among them, the overcurrent / short-circuit detection signal includes an overload voltage signal and an overload current signal.

[0066] In summary, the control circuit of the cooling fan provided by the embodiment of the present invention adds an open-circuit detection module and an overcurrent / short-circuit detection module to the drive circuit of the cooling fan to perform open-circuit detection and overcurrent / short-circuit detection on the cooling fan module. When the electric control box control system is working, it performs real-time overcurrent, short-circuit, and open-circuit detection on the cooling fan to monitor the operating state of the cooling fan in real time. If the cooling fan is open-circuited, overcurrent / short-circuited, it can reasonably control the start and stop of the cooling fan to protect the cooling fan and prevent it from being burned out due to overcurrent or open circuit, ensuring the heat dissipation of the electric control box.

[0067] As a feasible embodiment, combined with Figures 3-4As shown, the cooling fan module 5 includes a positive output terminal (+), a negative output terminal (-), and a first diode D1; the fan drive module 2 includes a first resistor R1, a second resistor R2, a first drive transistor Q1, and a drive switch unit 22; the open circuit detection module 3 includes a fifth resistor R5, a sixth resistor R6, and a voltage stabilization unit 32, and the overcurrent / short circuit detection module 4 includes an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a third drive transistor Q3, a first capacitor C1, and a second capacitor C2; the first end of the first resistor R1 is electrically connected to the drive signal output terminal 12, the second end of the first resistor R1 is respectively electrically connected to the first end of the second resistor R2 and the first end of the first drive transistor Q1, the first end of the drive switch unit 22 is respectively electrically connected to the second end of the first drive transistor Q1, and the third end of the first drive transistor Q1 is grounded to GND; the third end of the drive switch unit 22 is respectively electrically connected to the first end of the sixth resistor R6, the first end of the eighth resistor R8, and the first end of the ninth resistor R9; the second end of the drive switch unit 22 is respectively electrically connected to the first end of the fifth resistor R5, the second end of the sixth resistor R6, and the positive output terminal (+) of the cooling fan module 5; the second end of the fifth resistor R5 is respectively electrically connected to the negative output terminal (-) of the voltage stabilization unit 32 and the open circuit detection signal receiving terminal 11; the positive input terminal of the voltage stabilization unit 32 is grounded to GND; the negative output terminal (-) of the cooling fan module 5 is grounded to GND; the second end of the eighth resistor R8 is respectively electrically connected to the first end of the third drive transistor Q3 and the first end of the second capacitor C2, and the second end of the third drive transistor Q3, the second end of the second capacitor C2, and the second end of the ninth resistor R9 are all electrically connected to the first power supply (+12V); the first end of the eleventh resistor R11 is electrically connected to the third end of the third drive transistor Q3, and the second end of the eleventh resistor R11 is respectively electrically connected to the first end of the tenth resistor R10, the first end of the first capacitor C1, and the overcurrent / short circuit detection signal receiving terminal 13, and the second end of the tenth resistor R10 and the second end of the first capacitor C1 are both grounded to GND; the negative electrode of the first diode D1 is electrically connected to the positive output terminal (+) of the cooling fan module 5, and the positive electrode of the first diode D1 is grounded to GND.

[0068] Specifically, the first resistor and the second resistor R2 in the fan drive module 2 are pull-down resistors that provide a bias current for turning on and protecting the first drive transistor Q1. The internal resistances of the first resistor and the second resistor R2 are set to 2.2 kΩ and 10 kΩ respectively. The first drive transistor Q1 can be an NPN-type bipolar junction transistor, which is used to control the conduction or cutoff of the drive switch unit 22. The drive switch unit 22 is provided in the fan drive module 2. The drive switch unit 22 can be a commonly used switch tube in the circuit, such as a mechanical switch or a thyratron pulse switch, which is used to control the connection of the cooling fan module 5 to the first power supply (+12V) to achieve the purpose of turning on and off the power supply of the cooling fan.

[0069] For example, if the internal resistances of the fifth resistor R5, the sixth resistor R6, the eighth resistor R8, the ninth resistor R9, the tenth resistor R10, and the eleventh resistor R11 are set to 2.2 kΩ, 10 kΩ, 47 kΩ, 30 kΩ, 1 kΩ, 0.50 Ω, 10 kΩ, and 14 kΩ respectively. Among them, the ninth resistor R9 is a sampling resistor, and its resistance value can be adjusted according to the actual current limiting value of the cooling fan. When the cooling fan is working, the first driving transistor Q1 and the driving switch unit 22 are turned on. The voltage division ratio of the first power supply (+12V) transmitted through the ninth resistor R9 is detected by the fifth resistor R5 and the sixth resistor R6 to determine whether the cooling fan is open, that is, to identify whether the cooling fan is installed in the control circuit of the cooling fan. The voltage division ratio potential signal flowing through the ninth resistor R9 is fed back to the main control module 1 for analysis. For example, when the current of the cooling fan generates a voltage division ratio on the ninth resistor R9, when the current flowing through the ninth resistor R9 reaches the current limit point (such as 1.5A * 0.5 Ω = 0.75V), that is, the transistor Q3 is turned on, and the overcurrent / short-circuit detection module 4 generates an overcurrent / short-circuit detection signal and transmits it to the main control module 1 to indicate that the cooling fan is overcurrent or short-circuited. The main control module 1 performs overcurrent or short-circuit protection on the cooling fan; when the current of the cooling fan is the normal working current, the voltage division ratio generated on the ninth resistor R9 is lower than 0.75V, which will not turn on the transistor Q3, and the overcurrent / short-circuit detection module 4 will not generate an overcurrent / short-circuit detection signal, which can avoid misprotection of the cooling fan during normal operation.

[0070] Optionally, as shown in Figure 3 the driving switch unit 22 includes a third resistor R3, a fourth resistor R4, and a second driving transistor Q2; the first end of the third resistor R3 is electrically connected to the second end of the first driving transistor Q1 respectively, and the second end of the third resistor R3 is electrically connected to the first end of the second driving transistor Q2 and the first end of the fourth resistor R4 respectively; the second end of the second driving transistor Q2 is electrically connected to the first end of the fifth resistor R5, the second end of the sixth resistor R6, and the positive output terminal (+) of the cooling fan module 5 respectively; the third end of the second driving transistor Q2 is electrically connected to the second end of the fourth resistor R4, the first end of the sixth resistor R6, the first end of the eighth resistor R8, and the first end of the ninth resistor R9 respectively.

[0071] Specifically, as shown in Figure 3As shown in the figure, the third resistor R3 and the fourth resistor R4 of the drive switch unit 22 are pull-down resistors that provide a bias current for protecting and turning on the second drive transistor Q2. The internal resistances of the third resistor R3 and the fourth resistor R4 are both set to 10 kΩ. The second drive transistor Q2 is an NPN-type PMOS transistor (P-channel type). Using the Pulse Width Modulation (PWM) method, the main control module 1 outputs a drive signal through the drive signal output terminal 12 to control the conduction or disconnection of the first drive transistor Q1 and the second drive transistor Q2, thereby supplying power to or cutting off the power supply to the cooling fan from the first power supply (+12V), achieving the control function of the rotation and stop of the cooling fan. Using this modulation method, by adjusting the pulse width time of the drive signal, the intervals and durations of the conduction or disconnection of the second drive transistor Q2 can be quickly adjusted, which has the advantages of flexibility and speed, and is beneficial to improving the heat dissipation performance of the cooling fan.

[0072] For example, when the first drive transistor Q1 and the second drive transistor Q2 are conducting, the first power supply (+12V) supplies power to the cooling fan after passing through the ninth resistor R9, and the cooling fan starts and can dissipate heat normally; when the first drive transistor Q1 and the second drive transistor Q2 are disconnected, the first power supply (+12V) is disconnected from the cooling fan, and the cooling fan is powered off.

[0073] Optionally, as shown in Figure 4 the figure, the drive switch unit 22 includes a third diode D3 and a relay K; the second terminal of the first drive transistor Q1 is electrically connected to the first terminal 1 of the relay K and the positive electrode of the third diode D3 respectively; the fifth terminal 5 of the relay K and the negative electrode of the third diode D3 are both electrically connected to the first power supply (+12V); the second terminal 2 of the relay K is electrically connected to the first terminal of the fifth resistor R5, the second terminal of the sixth resistor R6, and the positive output terminal (+) of the cooling fan module 5 respectively; the third terminal 3 of the relay K is electrically connected to the first terminal of the sixth resistor R6, the first terminal of the eighth resistor R8, and the first terminal of the ninth resistor R9 respectively; the relay K includes a changeover switch K1, and the changeover switch K1 is connected to the third terminal 3 of the relay K or the fourth terminal 4 of the relay K; the fourth terminal 4 of the relay K is in neutral.

[0074] Specifically, a third diode D3 and a relay K are provided in the drive switch unit 22. The third diode D3 is connected in parallel with the relay K to play a protective role, preventing the high voltage generated by self-inductance from damaging the first drive transistor Q1 when the relay K is powered off and released. The main control module 1 outputs a drive signal through the drive signal output terminal 12 to control the conduction or disconnection of the relay K. When the switch K1 of the relay K is switched to the third terminal 3, the relay K conducts, and the first power supply (+12V) supplies power to the cooling fan through the ninth resistor R9, and the cooling fan starts to dissipate heat normally. When the switch K1 of the relay K is switched to the fourth terminal 4, the relay K disconnects, the first power supply (+12V) is disconnected from the cooling fan, and the cooling fan is powered off and stops working.

[0075] Furthermore, a voltage stabilizing unit 32 is provided in the open circuit detection module 3 to protect the main control module 1.

[0076] Optionally, as shown in Figure 3 the voltage stabilizing unit 32 includes a voltage stabilizing diode DW4; the negative electrode of the voltage stabilizing diode DW4 is electrically connected to the second terminal of the fifth resistor R5 and the open circuit detection signal receiving terminal 11 respectively; the positive electrode of the voltage stabilizing diode DW4 is grounded to GND.

[0077] Specifically, the voltage stabilizing diode DW4 refers to a diode that uses the reverse breakdown state of the PN junction, and its current can vary within a large range while the voltage remains basically unchanged, to achieve the function of voltage stabilization. It can clamp the potential of the open circuit detection signal output from the open circuit detection signal output terminal 31 at a fixed potential, such as 5.1V, to avoid overvoltage damage to the chip of the main control module 1 due to too high a level of the detection signal, thus playing a role in protecting the chip of the main control module 1.

[0078] Based on the above embodiments, as shown in Figure 4 the voltage stabilizing unit 32 includes a second diode D2; the positive electrode of the second diode D2 is electrically connected to the second terminal of the fifth resistor R5 and the open circuit detection signal receiving terminal 11 respectively; the negative electrode of the second diode D2 is electrically connected to the second power supply; wherein, the voltage of the second power supply (+5V) is lower than the voltage of the first power supply (+12V).

[0079] Specifically, the voltage stabilizing unit 32 can also replace the voltage stabilizing diode DW4 with an ordinary second diode D2, and connect the negative electrode of the second diode D2 to the second power supply (+5V), which can clamp the level of the open circuit detection signal of the cooling fan to the chip voltage of the main control module 1, avoiding overvoltage damage to the chip of the main control module 1 due to too high a level of the detection signal, thus playing a role in protecting the chip of the main control module 1.

[0080] Based on the above embodiments, continue to combine with Figure 1As shown, the control circuit further includes an alarm module 6, and the alarm module 6 is connected to the main control module 1; the main control module 1 is further configured to output an alarm signal according to the open - circuit detection signal and the over - current / short - circuit detection signal, and the alarm module 6 issues an alarm prompt according to the alarm signal.

[0081] Specifically, the alarm module 6 can be set in the electric control box system of the central oil fume purification system, or set in the human - machine operation platform of the cooling fan control system. The alarm module 6 is connected to the main control module 1. When the main control module 1 confirms that the cooling fan is open - circuited or over - current / short - circuited, it outputs an alarm signal to the alarm module 6, and the alarm module 6 issues an alarm prompt. Among them, the alarm prompt can be a flashing alarm light, an alarm prompt sound, etc., to warn the staff and facilitate timely problem troubleshooting.

[0082] Based on the above - mentioned embodiments, continue to combine Figure 1 As shown, the control circuit further includes a cloud end 7, and the cloud end 7 is communicatively connected to the main control module 1. The main control module 1 is further configured to upload the operating state of the cooling fan module 5 and the alarm prompt to the cloud end 7.

[0083] Specifically, the main control module 1 uploads the detected operating state of the cooling fan module 5 and the alarm prompt to the cloud, and remotely notifies the operator of the operating state of the cooling fan module 5 and the alarm prompt through the cloud platform or the mobile phone APP, so that the operator can immediately protect the cooling fan from open - circuit, over - current, and short - circuit.

[0084] Based on the same inventive concept, the embodiment of the present invention further provides a control method for a cooling fan, which is used to control the control circuit of the cooling fan provided in the above - mentioned embodiment. The control method includes:

[0085] S101. Receive an open - circuit detection signal, and determine the connection state of the cooling fan module according to the open - circuit detection signal.

[0086] Specifically, when the main control module 1 is powered on, the open - circuit detection signal receiving end 11 receives the open - circuit detection signal generated by the open - circuit detection module 3, and determines the connection state of the cooling fan module 5 based on the open - circuit detection signal. Among them, the open - circuit detection signal includes a high level and a low level, and the connection state includes open - circuit and path. For example, when the signal received by the main control module 1 is at a low level, it is determined that the connection state of the cooling fan module 5 is a path, that is, the cooling fan is connected to the cooling fan control system; when the signal received by the main control module 1 is at a high level, it is determined that the connection state of the cooling fan module 5 is that the cooling fan is not connected to the cooling fan control system.

[0087] S102. According to the connection state, output a drive signal to the fan drive module, so that the fan drive module controls the operating state of the cooling fan module according to the drive signal.

[0088] Among them, the operating states include on and off.

[0089] Specifically, when the main control module 1 determines that the connection state of the cooling fan module 5 is a conducting path, it indicates that the cooling fan is connected to the cooling fan control system, and the cooling fan can be started for heat dissipation. The main control module 1 outputs a driving signal to the driving signal receiving end 21 of the fan driving module 2 through the driving signal output end 2. Among them, the driving signal includes a high level and a low level. The fan driving module 2 controls the first power supply (+12V) to supply power to or cut off power from the cooling fan module 5 according to the driving signal, so as to control the on and off of the cooling fan in the cooling fan module 5.

[0090] For example, when the main control module 1 outputs a high level, the fan driving module 2 controls the cooling fan module 5 to be electrically connected to the first power supply (+12V) according to the high level, so as to control the operating state of the cooling fan module 5 to be on, and the cooling fan exhausts heat for the electronic control box of the central range hood; or, when the main control module 1 outputs a low level, the fan driving module 2 controls the power supply to be disconnected from the cooling fan module 5 according to the low level, so that the cooling fan stops working or remains in a standby state.

[0091] S103. Receive an overcurrent / short-circuit detection signal, and control the operating state of the cooling fan module according to the overcurrent / short-circuit detection signal.

[0092] Specifically, when the cooling fan in the cooling fan module 5 is turned on, the overcurrent / short-circuit detection module 4 monitors the working current of the cooling fan in real time, generates an overcurrent / short-circuit detection signal based on the working current, and outputs the overcurrent / short-circuit detection signal to the overcurrent / short-circuit detection signal receiving end 13 of the main control module 1 through the overcurrent / short-circuit detection signal output end 41. Among them, the overcurrent / short-circuit detection signal includes an overvoltage signal and an overcurrent signal.

[0093] The main control module 1 can determine that the operating state of the cooling fan module 5 is overcurrent or short circuit at this time according to the received overvoltage signal or overcurrent signal, and there is a risk of damaging the cooling fan.

[0094] Furthermore, control the driving signal output end 12 of the main control module 1 to output a low level, control the fan driving module 2 to cut off the power supply of the first power supply (+12V) to the cooling fan module 5, and the cooling fan stops working, which can avoid the cooling fan from being burned out due to overcurrent or short circuit, thereby protecting the cooling fan.

[0095] Based on the above embodiments, Figure 6 is a flowchart of another control method for a cooling fan provided by an embodiment of the present invention; Figure 7 is a schematic diagram of the control logic of a control circuit for a cooling fan provided by an embodiment of the present invention. AsFigure 6 As shown, the open - circuit detection signal includes a first potential signal and a second potential signal. The amplitude of the first potential signal is less than that of the second potential signal. The connection state includes a conducting path and an open circuit. Another control method for a cooling fan provided by an embodiment of the present invention includes:

[0096] S201. Receive the open - circuit detection signal.

[0097] S202. When the open - circuit detection signal is the first potential signal, determine that the connection state of the cooling fan module is a conducting path.

[0098] Specifically, in combination with Figure 3 and Figure 4 、 Figure 6 and Figure 7 As shown, when the open - circuit detection module 3 works, the first power supply (+12V) supplies a detection voltage to the cooling fan through the ninth resistor R9 and the sixth resistor R6. Among them, the sixth resistor R6 and the fifth resistor R5 are in parallel in the open - circuit detection module 3 circuit. When the fan plug CN2 is inserted into the socket CN1, usually the internal resistance of the cooling fan is small, only a few dozen ohms, which will directly pull the potential at point A in the open - circuit detection module 3 of the cooling fan down to the potential of GND. After passing through the resistor R5, the potential signal transmitted to the main control module 1 (i.e., the AN3 / P1.3 pin) of the main control module 1 is the first potential signal, that is, a low level. At this time, the main control module 1 determines according to the low level that the cooling fan is normally inserted into the control circuit of the cooling fan and can provide normal heat dissipation work.

[0099] Among them, Figure 3 and Figure 4 Point A is the common potential point of the second end of the sixth resistor R6, the first end of the fifth resistor R5, and the second end of the second driving triode Q2; Figure 4 Point A is the common potential point of the connection point of the second end of the sixth resistor R6, the first end of the fifth resistor R5, and the second end 2 of the relay K.

[0100] S203. When the open - circuit detection signal is the second potential signal, determine that the connection state of the cooling fan module is an open circuit.

[0101] In combination with Figure 3As shown, the second terminal of the fifth resistor R5 can be connected to the zener diode DW4. When the detection voltage provided by the first power supply (+12V) is applied, when the fan plug CN2 is not inserted into the socket CN1, or when the cooling fan is damaged, there is no internal resistance on the socket CN1 at this time, and no voltage division will occur. The first power supply (+12V) supplies the detection voltage to the cooling fan through the ninth resistor R9, the sixth resistor R6, and the fifth resistor R5. The zener diode DW4 will stably clamp the voltage of the open-circuit detection output terminal 31 at the 5.1V zener potential, and the potential signal transmitted to the main control module 1 of the main control module 1 (i.e., the AN3 / P1.3 pin) is the second potential signal, that is, a high level; or, combined with Figure 4 As shown, the second terminal of the fifth resistor R5 can be connected to the anode of the second diode D2, and the cathode of the second diode D2 is connected to the second power supply (+5V). When the fan plug CN2 is not inserted into the socket CN1, or when the cooling fan is damaged, there is no internal resistance on the socket CN1 at this time, and no voltage division will occur. The first power supply (+12V) supplies the detection voltage to the cooling fan through the ninth resistor R9, the sixth resistor R6, and the fifth resistor R5. The second power supply (+5V) stably clamps the voltage of the open-circuit detection output terminal 31 at the 5V zener potential, and the potential signal transmitted to the main control module 1 of the main control module 1 (i.e., the AN3 / P1.3 pin in the figure) is also the second potential signal, that is, a high level; at this time, the main control module 1 determines according to the high level that the cooling fan is not installed or has an open circuit at this time (as Figure 7 shown), indicating that there is an open-circuit fault in the cooling fan at this time, and it cannot provide normal heat dissipation to the electric control box, and needs to be repaired and maintained in time.

[0102] It should be noted that according to the different performances of the zener diode DW4, the zener potential of 5.1V will also change, and no specific limitation is made here. By setting the second power supply (+5V) and the second diode D2 or the zener diode DW4 to clamp the voltage of the open-circuit detection output terminal 31 to the chip voltage of the main control module 1, it is possible to avoid damaging the chip of the main control module 1 due to too high or overvoltage of the detection signal.

[0103] S204. When the connection state of the cooling fan module is a path, output a first level signal to the fan drive module, so that the fan drive module controls the start of the cooling fan according to the first level signal.

[0104] Among them, the drive signal includes a first level signal and a second level signal, the amplitude of the first level signal is greater than the amplitude of the second level signal, the connection state includes a path, the operating state also includes start and stop, and the cooling fan module 5 includes a cooling fan.

[0105] Specifically, combined with Figure 3As shown, when the main control module 1 determines that the cooling fan is inserted into the cooling fan control system normally and can provide normal heat dissipation, it can send a first level signal, that is, a high level, through the drive signal output terminal 12 (i.e., the PWM / P1.2 pin in the figure), turn on the first drive triode Q1 through the resistor R1, make Q1 conduct, pull down the gate of the second drive triode Q2, turn on the switch of the second drive triode Q2, and supply power to the cooling fan through the sampling ninth resistor R9 by the first power supply (+12V). At this time, the cooling fan starts to rotate and work to dissipate heat for the main control box of the central oil fume purification system.

[0106] S205. When the connection state of the cooling fan module is a path, output a second level signal to the fan drive module so that the fan drive module controls the cooling fan to stop rotating according to the second level signal.

[0107] Specifically, continue to combine with Figure 3 As shown, when the main control module 1 determines that the cooling fan is inserted into the cooling fan control system normally and can provide normal heat dissipation, it can also send a second level signal, that is, a low level, through the drive signal output terminal 12 (i.e., the PWM / P1.2 pin in the figure), make the first drive triode Q1 cut off through the resistor R1. Since the internal resistance of the ninth resistor R9 is set to be small, such as R50 (i.e., 0.5 ohm), the gate potential of the second drive triode Q2 will be pulled up to 12V by the fourth resistor R4 through the first power supply (+12V) of the ninth resistor R9, turn off the switch of the second drive triode Q2, and the power supply 12V provided by the first power supply (+12V) cannot supply power to the cooling fan normally through the ninth resistor R9. At this time, the cooling fan gradually stops rotating, realizing the start-stop control of the cooling fan.

[0108] S206. When the connection state of the cooling fan module is a path, alternately output the first level signal and the second level signal to the fan drive module so that the fan drive module controls the running speed of the cooling fan according to the first level signal and the second level signal.

[0109] Specifically, continue to combine with Figure 3 As shown, it can also automatically adjust the speed of the cooling fan in combination with the ambient temperature and the temperature of the control box. During the power-on operation of the cooling fan, high and low levels are alternately output through the drive signal output terminal 12 (i.e., the PWM / P1.2 pin in the figure). When the high level is continuously output, the fan of the cooling fan keeps rotating; when the low level is output, the cooling fan gradually stops rotating to reduce the running speed of the cooling fan. By automatically controlling the speed of the cooling fan, it can be avoided that the cooling fan always rotates at full speed, thus enhancing the service life of the cooling fan.

[0110] Optionally, the duration of the first level signal and the duration of the second level signal are different. By setting the durations of the first level signal and the second level signal, the rotation speed of the cooling fan is automatically controlled to gradually increase or gradually decrease. On the one hand, the service life of the cooling fan can be enhanced, and on the other hand, electric energy can be saved.

[0111] S207. While the fan driving module controls the cooling fan to turn off according to the second level signal, continue to execute S201, S202, and S203.

[0112] Specifically, continue to combine with Figure 3 As shown, since the fan driving module 2 and the open circuit detection module 3 are connected in parallel, it is also possible to turn on the open circuit detection module 3 to detect whether the cooling fan is properly inserted into the control circuit while the fan driving module 2 controls the cooling fan to turn off according to the second level signal. The durations of the first level signal and the second level signal can cycle in units of seconds or minutes. When the drive signal output terminal 12 (i.e., the PWM / P1.2 pin in the figure) outputs a low level, the cooling fan is briefly shut down (the stop time is in the order of dozens of microseconds), and step 201 is continued to quickly detect whether the cooling fan is open by the open circuit detection module 3; when the drive signal output terminal 12 (i.e., the PWM / P1.2 pin in the figure) outputs a high level, the cooling fan is immediately turned on again. The shutdown time is short and actually does not affect the operation of the cooling fan at all. In this way, it is possible to constantly detect whether there is an open circuit fault in the cooling fan during operation.

[0113] S208. Receive the overcurrent / short circuit detection signal and control the operating state of the cooling fan module according to the overcurrent / short circuit detection signal.

[0114] Specifically, continue to combine with Figure 3 As shown, when the cooling fan is operating normally, the ninth resistor R9 is used for voltage division, causing the third driving transistor Q3 to be cut off. Usually, the rated current of the cooling fan is set to 0.5A, that is, the supply current I of the first power supply (+12V) is 0.5A. The internal resistance of the ninth resistor R9 is set to R50 (i.e., 0.5 ohm). At this time, the voltage division on the ninth resistor R9 is calculated by the formula V = I * R:

[0115] V R9 = I * R9 = 0.5A * 0.5 ohm = 0.25V; the normal operating current of the cooling fan is 0.5A. The voltage division ratio on the ninth resistor R9 cannot cause the third driving transistor Q3 to conduct, that is, the first driving transistor Q3 is cut off. At this time, the voltage (potential) on the overcurrent / short circuit detection module 4 is pulled down by the tenth resistor R10, and the overcurrent / short circuit signal transmitted to the overcurrent / short circuit detection signal receiving terminal 13 of the main control module 1 is a low level, indicating that the cooling fan is in a normal operating state.

[0116] When the cooling fan operates with abnormal overcurrent, the third driving transistor Q3 conducts. The voltage of the first power supply (+12V) forms a voltage division on the tenth resistor R10 and the eleventh resistor R11 through the third driving transistor Q3. That is, the voltage division on the tenth resistor R10 is:

[0117] V R10 = V * R10 / (R11 + R10) = 12V * 10 / (14 + 10) = 5V. That is, the voltage at point B in the figure is 5V. At this time, the overcurrent / short-circuit detection signal transmitted from point B in the overcurrent / short-circuit detection circuit to the short-circuit detection signal receiving end 13 (pin AN4 / P3.2 in the figure) is a 5V high level. The main control module 1 determines that the cooling fan is detected as overcurrent / short-circuit based on the 5V high level.

[0118] Among them, the condition for the third driving transistor Q3 is that its base voltage is above 0.75V, that is, the voltage division on the ninth resistor R9 reaches above 0.75V. In this embodiment, the overcurrent of the cooling fan is set to 1.5A. When the internal resistance of the ninth resistor R9 is R50 (i.e., 0.5 ohm), the voltage division on the ninth resistor R9 is calculated by the formula V = I * R:

[0119] V R9 = I * R9 = 1.5A * 0.5 ohm = 0.75V. Therefore, when the current of the cooling fan exceeds 1.5A, the voltage division ratio on the ninth resistor R9 causes the third driving transistor Q3 to conduct. Therefore, the voltage (potential) on the overcurrent / short-circuit detection circuit of the first power supply (+12V) is divided into 5V on the tenth resistor R10 and transmitted to the short-circuit detection signal receiving end 13 (pin AN4 / P3.2 in the figure) of the main control module 1 as a high level. The high level indicates that the cooling fan is in an overcurrent or short-circuit state. At this time, the main control module 1 drives the signal output end 12 (i.e., pin PWM / P1.2 in the figure) to emit a low level, which makes the first driving transistor Q1 cut off through the resistor R1 and turns off the switch second driving transistor Q2. The first power supply (+12V) stops supplying power to the cooling fan, and at this time, the cooling fan gradually stops rotating, avoiding damage to the fan or the cooling fan drive control circuit.

[0120] It should be noted that according to the actual overcurrent protection of the cooling fan used, the overcurrent parameters of the fan can be flexibly adjusted to match the actual overcurrent protection of the fan used. In this embodiment, the overcurrent of the cooling fan is set to 1.5A, and other specific embodiments are not listed one by one here.

[0121] Based on the above embodiment, continuing to combine Figure 1 As shown, optionally, the control circuit further includes an alarm module 6, and the alarm module 6 is connected to the main control module 1. In Figure 6After steps S203 and S207 of the present invention, another control method for the central oil fume purification system provided by the embodiments of the present invention further includes:

[0122] S209. Control the alarm module to issue an alarm prompt.

[0123] Specifically, when the cooling fan is open circuit or overcurrent / short circuit, the alarm module issues an alarm prompt to prompt the operator to perform maintenance in time, avoid the influence of the uninserted cooling fan on the heat dissipation of the electric control box, reduce the damage of the fan due to overcurrent, and play the role of timely maintenance prompt.

[0124] On the basis of the above embodiments, continuing to combine Figure 1 As shown, optionally, the control circuit further includes a cloud 7, and the cloud is communicatively connected to the main control module.

[0125] Among them, the cloud refers to an application mode that connects IT resources (such as servers, storage, applications, and services, etc.) through the Internet, forms a shared resource pool, provides on-demand services to users, and can achieve rapid deployment of resources. After Figure 6 steps S203 and S208 of the present invention, another control method for the central oil fume purification system provided by the embodiments of the present invention further includes:

[0126] S210. Upload the operating status of the cooling fan module and the alarm prompt to the cloud.

[0127] The main control module 1 uploads the information of the open circuit, overcurrent / short circuit of the detected cooling fan module and the alarm prompt to the cloud, and remotely notifies the operator of the operating information of the cooling fan through the cloud platform or the mobile phone APP, so as to achieve the purpose of early maintenance and ensure the normal operation of the cooling fan.

[0128] Based on the same inventive concept, the embodiments of the present invention further provide a cooling fan control system, including the control circuit of the cooling fan provided in the above embodiments.

[0129] It should be noted that the cooling motor control system provided by the embodiments of the present invention can execute the control method of the cooling motor provided in any embodiment of the present invention, and has the corresponding functional modules and beneficial effects for executing the control method of the cooling motor, which will not be elaborated here.

[0130] Note that the above is only the preferred embodiment of the present invention and the technical principles applied. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein. The features of the various embodiments of the present invention can be partially or fully coupled or combined with each other, and can cooperate with each other in various ways and be technically driven. Various obvious changes, re-adjustments, combinations with each other and substitutions can be made by those skilled in the art without departing from the protection scope of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments. Without departing from the concept of the present invention, more other equivalent embodiments can be included, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A control circuit for a cooling fan, characterized in that, It includes a main control module, a fan driving module, an open circuit detection module, an overcurrent / short circuit detection module, and a cooling fan module. The main control module is electrically connected to the fan driving module, the open circuit detection module, and the overcurrent / short circuit detection module respectively. The cooling fan module is electrically connected to the fan driving module and the open circuit detection module respectively. The fan driving module is also electrically connected to the overcurrent / short circuit detection module and is connected in parallel with the open circuit detection module. The main control module includes a driving signal output terminal, an open circuit detection signal receiving terminal, and an overcurrent / short circuit detection signal receiving terminal. The fan driving module includes a driving signal receiving terminal. The overcurrent / short circuit detection module includes an overcurrent / short circuit detection signal output terminal. The open circuit detection module includes an open circuit detection signal output terminal. The open circuit detection signal output terminal is electrically connected to the open circuit detection signal receiving terminal for transmitting an open circuit detection signal. The driving signal output terminal is electrically connected to the driving signal receiving terminal for transmitting a driving signal. The overcurrent / short circuit detection signal output terminal and the overcurrent / short circuit detection signal receiving terminal are electrically connected for transmitting an overcurrent / short circuit detection signal. The main control module is used to determine the connection state of the cooling fan module according to the open circuit detection signal. The connection state includes a path and an open circuit. The main control module is also used to output the driving signal according to the connection state. The fan driving module is used to control the operating state of the cooling fan module according to the driving signal. The operating state also includes start and stop. The main control module is also used to control the operating state of the cooling fan module according to the overcurrent / short circuit detection signal.

2. The control circuit according to claim 1, wherein The cooling fan module includes a positive output terminal, a negative output terminal, and a first diode. The fan driving module includes a first resistor, a second resistor, a first driving transistor, and a driving switch unit. The open circuit detection module includes a fifth resistor, a sixth resistor, and a voltage stabilizing unit. The overcurrent / short circuit detection module includes an eighth resistor, a ninth resistor, a tenth resistor, an eleventh resistor, a third driving transistor, a first capacitor, and a second capacitor. The negative electrode of the first diode is electrically connected to the positive output terminal of the cooling fan module, and the positive electrode of the first diode is grounded. The first end of the first resistor is electrically connected to the driving signal output terminal. The second end of the first resistor is electrically connected to the first end of the second resistor and the first end of the first driving transistor respectively. The first end of the driving switch unit is electrically connected to the second end of the first driving transistor respectively. The third end of the first driving transistor is grounded. The third terminal of the driving switch unit is electrically connected to the first terminal of the sixth resistor, the first terminal of the eighth resistor, and the first terminal of the ninth resistor respectively; the second terminal of the driving switch unit is electrically connected to the first terminal of the fifth resistor, the second terminal of the sixth resistor, and the positive output terminal of the cooling fan module respectively; the second terminal of the fifth resistor is electrically connected to the negative output terminal of the voltage stabilizing unit and the open-circuit detection signal receiving terminal respectively; the positive input terminal of the voltage stabilizing unit is grounded; the negative output terminal of the cooling fan module is grounded; The second terminal of the eighth resistor is electrically connected to the first terminal of the third driving transistor and the first terminal of the second capacitor respectively. The second terminal of the third driving transistor, the second terminal of the second capacitor, and the second terminal of the ninth resistor are all electrically connected to the first power supply. The first terminal of the eleventh resistor is electrically connected to the third terminal of the third driving transistor. The second terminal of the eleventh resistor is electrically connected to the first terminal of the tenth resistor, the first terminal of the first capacitor, and the overcurrent / short-circuit detection signal receiving terminal respectively. The second terminal of the tenth resistor and the second terminal of the first capacitor are grounded.

3. The control circuit according to claim 2, characterized in that, The driving switch unit includes a third resistor, a fourth resistor, and a second driving transistor; The first terminal of the third resistor is electrically connected to the second terminal of the first driving transistor respectively. The second terminal of the third resistor is electrically connected to the first terminal of the second driving transistor and the first terminal of the fourth resistor respectively; The second terminal of the second driving transistor is electrically connected to the first terminal of the fifth resistor, the second terminal of the sixth resistor, and the positive output terminal of the cooling fan module respectively; The third terminal of the second driving transistor is electrically connected to the second terminal of the fourth resistor, the first terminal of the sixth resistor, the first terminal of the eighth resistor, and the first terminal of the ninth resistor respectively.

4. The control circuit according to claim 2, wherein, The driving switch unit includes a third diode and a relay; The second terminal of the first driving transistor is electrically connected to the first terminal of the relay and the positive electrode of the third diode respectively. The fifth terminal of the relay and the negative electrode of the third diode are both electrically connected to the first power supply; The second terminal of the relay is electrically connected to the first terminal of the fifth resistor, the second terminal of the sixth resistor, and the positive output terminal of the cooling fan module respectively; The third terminal of the relay is electrically connected to the first terminal of the sixth resistor, the first terminal of the eighth resistor, and the first terminal of the ninth resistor respectively; The relay includes a changeover switch which is connected to the third terminal of the relay or the fourth terminal of the relay; the fourth terminal of the relay is in neutral.

5. The control circuit according to claim 3 or 4, characterized in that, The voltage stabilizing unit includes a zener diode; The negative electrode of the zener diode is electrically connected to the second terminal of the fifth resistor and the open-circuit detection signal receiving terminal respectively; the positive electrode of the zener diode is grounded.

6. The control circuit according to claim 3 or 4, characterized in that, The voltage stabilizing unit includes a second diode; The positive electrode of the second diode is electrically connected to the second terminal of the fifth resistor and the open-circuit detection signal receiving terminal respectively; the negative electrode of the second diode is electrically connected to the second power supply; Wherein, the voltage of the second power supply is lower than that of the first power supply.

7. The control circuit according to claim 1, wherein The control circuit further includes an alarm module, and the alarm module is connected to the main control module; The main control module is further configured to output an alarm signal according to the open - circuit detection signal and / or the over - current / short - circuit detection signal, and the alarm module issues an alarm prompt according to the alarm signal.

8. The control circuit according to claim 7, wherein The control circuit further includes a cloud, and the cloud is communicatively connected to the main control module; The main control module is further configured to upload the operating state of the cooling fan module and the alarm prompt to the cloud.

9. A control method for a cooling fan, which is used to control the control circuit of the cooling fan according to any one of claims 1-8, characterized in that, The control method includes: Receiving the open - circuit detection signal, and determining the connection state of the cooling fan module according to the open - circuit detection signal; the connection state includes a path and an open circuit; According to the connection state, outputting the drive signal to the fan drive module, so that the fan drive module controls the operating state of the cooling fan module according to the drive signal; the operating state includes starting and stopping; Receiving the over - current / short - circuit detection signal, and controlling the operating state of the cooling fan module according to the over - current / short - circuit detection signal.

10. The control method according to claim 9, characterized in that, The open - circuit detection signal includes a first potential signal and a second potential signal, the amplitude of the first potential signal is less than that of the second potential signal, and the connection state includes a path and an open circuit; Receiving the open - circuit detection signal, and determining the connection state of the cooling fan module according to the open - circuit detection signal; includes: Receiving the open - circuit detection signal; When the open - circuit detection signal is the first potential signal, determining that the connection state of the cooling fan module is a path; When the open - circuit detection signal is the second potential signal, determining that the connection state of the cooling fan module is an open circuit.

11. The control method according to claim 10, wherein The drive signal includes a first level signal and a second level signal, the amplitude of the first level signal is greater than that of the second level signal, the connection state includes a path, the operating state further includes starting and stopping, and the cooling fan module includes a cooling fan; According to the connection state, outputting the drive signal to the fan drive module, so that the fan drive module controls the operating state of the cooling fan module according to the drive signal, includes: When the connection state of the cooling fan module is a path, outputting the first level signal to the fan drive module, so that the fan drive module controls the cooling fan to start according to the first level signal; Or, when the connection state of the cooling fan module is a path, outputting the second level signal to the fan drive module, so that the fan drive module controls the cooling fan to stop rotating according to the second level signal.

12. The control method according to claim 11, wherein According to the connection state, outputting the drive signal to the fan drive module, so that the fan drive module controls the operating state of the cooling fan module according to the drive signal, includes: When the connection state of the heat dissipation fan module is a conducting path, alternately output the first level signal and the second level signal to the fan driving module, so that the fan driving module controls the running speed of the heat dissipation fan according to the first level signal and the second level signal.

13. The control method according to claim 11, wherein The duration of the first level signal is different from the duration of the second level signal.

14. The control method according to claim 12, characterized in that, When alternately outputting the first level signal and the second level signal to the fan driving module, so that the fan driving module controls the running speed of the heat dissipation fan according to the first level signal and the second level signal, the control method further includes: While the fan driving module controls the heat dissipation fan to turn off according to the second level signal, receive the open circuit detection signal, and determine the connection state of the heat dissipation fan module according to the open circuit detection signal.

15. A heat dissipation fan control system, characterized in that, It includes the control circuit of the heat dissipation fan according to any one of claims 1-8.

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