A speed control device for a cooling fan

Abstract

This utility model relates to the field of cooling fan control technology, and provides a speed control device for cooling fans. Based on the heat dissipation requirements of the electrical load, a corresponding cooling fan is configured to cool the working environment. Therefore, one end of the voltage regulation circuit is connected to the rectifier module. By detecting voltage changes, it is determined whether the electrical load is connected, and then the switching module is driven in real time to conduct the power circuit for heat dissipation, so as to realize the automatic start of the cooling fan. At the same time, a temperature monitoring speed control module is set and installed near the placement position of the electrical load and connected to the control terminal of the voltage regulation circuit to provide feedback adjustment of the temperature of the electrical load. While meeting the heat dissipation requirements, it also achieves energy saving and noise reduction, meeting the low cost requirements. The cooling fan can be turned off when there is no load in standby mode, the cooling fan runs at low speed under small load, and the cooling fan runs at high speed under full load, meeting the green energy saving requirements.

Description

Technical Field

[0001] This utility model relates to the field of cooling fan control technology, and in particular to a speed control device for cooling fans. Background Technology

[0002] To ensure stable equipment operation, cooling fans are typically installed to control the ambient temperature. Existing cooling fans are directly connected to the power supply circuit via a switching circuit, meaning they operate whenever power is supplied. Therefore, they run even under no-load or low-load conditions. This not only wastes energy but also generates significant noise, fails to meet energy conservation and emission reduction requirements, and makes it difficult to achieve Energy Efficiency Level VI.

[0003] There are also software MCUs on the market that control cooling fans to achieve energy saving and noise reduction. Their working principle is as follows:

[0004] The startup mechanism is configured with a load access detection circuit connected to the MCU. When a load is detected, the MCU outputs an enable signal to turn on the power supply circuit for the cooling fan.

[0005] The speed control mechanism involves placing a thermistor near the heat source to collect temperature signals and feed them back to the MCU. The MCU then determines whether the temperature exceeds a set threshold. If so, it controls the speed controller to adjust the speed of the cooling fan to match the heat dissipation requirements.

[0006] However, such driving circuits require MCUs or dedicated chips to implement, resulting in complex circuitry and high costs. Utility Model Content

[0007] This invention provides a speed control device for cooling fans, which solves the technical problems of existing cooling fan control mechanisms relying on MCU drivers, resulting in complex circuits and high costs.

[0008] To solve the above technical problems, this utility model provides a speed control device for a cooling fan, including a voltage regulation circuit, a switching module, a temperature monitoring speed control module, and a rectifier module; the input terminal of the rectifier module is connected to the power supply output circuit of the electrical load, and the output terminal is electrically connected to the voltage regulation circuit, the temperature monitoring speed control module, and the cooling fan; the voltage regulation circuit is also connected to the control terminal of the switching module; the temperature monitoring speed control module is installed near the placement position of the electrical load and is connected to the control terminal of the voltage regulation circuit; the cooling fan is grounded through the switching module.

[0009] This basic solution is based on the heat dissipation requirements of the electrical load. It configures corresponding cooling fans to cool the working environment. Therefore, one end of the voltage regulation circuit is connected to the rectifier module. By detecting voltage changes, it determines whether the electrical load is connected, and then drives the switching module in real time to conduct the heat dissipation circuit, enabling the cooling fan to automatically start. Simultaneously, a temperature monitoring and speed control module is installed near the electrical load and connected to the control terminal of the voltage regulation circuit to provide feedback adjustment of the electrical load temperature. This satisfies the heat dissipation requirements while achieving energy saving and noise reduction, meeting low-cost requirements. The cooling fan can be turned off in standby mode with no load, runs at low speed under light load, and runs at high speed under full load, meeting green energy-saving requirements.

[0010] In a further embodiment, the voltage regulation circuit includes a load detection module and a drive module. One end of the load detection module is connected to the rectifier module, and the other end is connected to the control terminal of the drive module. The input terminal of the drive module is connected to the rectifier module, and the output terminal is connected to the control terminal of the switch module. The temperature monitoring and speed regulation module is connected to the control terminal of the drive module.

[0011] In a further embodiment, the load detection module includes a first diode ZD1 and a first resistor R1;

[0012] The cathode of the first diode ZD1 is connected to the rectifier module, and the anode is connected to the control terminal of the drive module through the first resistor R1.

[0013] The first diode ZD1 is a Zener diode.

[0014] This solution uses a Zener diode as the core of the load detection mechanism. By utilizing its reverse breakdown characteristics, the voltage threshold when the cooling fan is turned on can be set. This voltage is detected from the power supply output circuit of the electrical load, thus enabling load self-detection and automatic start-up control of the cooling fan, meeting the standby power consumption and average efficiency requirements of Energy Efficiency VI.

[0015] In a further embodiment, the driving module includes a first switch Q1, a second resistor R2, a third resistor R3, and a first capacitor C1;

[0016] The first terminal of the first switching transistor Q1 is connected to the rectifier module through the second resistor R2, and the second terminal is connected to the control terminal of the switching module. The control terminal is connected to the load detection module and the temperature monitoring and speed control module.

[0017] One end of the third resistor R3 is connected to the control terminal of the first switch Q1, and the other end is grounded;

[0018] The first capacitor C1 is connected in parallel with the third resistor R3.

[0019] This solution uses a first switching transistor Q1 to drive the fan. Its control terminal is connected to a third resistor R3 and a first resistor R1. Based on the voltage division of the resistors, the conduction point of the first switching transistor Q1 can be customized according to the requirements, and thus the conduction voltage can be customized to adapt to the load size. The cooling fan can be set to start according to the load status of the electrical load. The structure is simple and the design cost is low.

[0020] In a further embodiment, the temperature monitoring and speed control module includes a thermistor NTC, one end of which is connected to the rectifier module and the other end is connected to the control terminal of the switch module.

[0021] This solution places a thermistor NTC near the location of the electrical load. By connecting the control terminal of its voltage regulation circuit, the current value at the control terminal of the first switching transistor Q1 is changed by the change in the resistance value while monitoring the temperature, thereby realizing the self-adjustment of the cooling fan speed. It has a high degree of intelligence.

[0022] In a further embodiment, the switching module includes a second switching transistor Q2, a fourth resistor R4, and a second capacitor C2;

[0023] The first terminal of the second switching transistor Q2 is connected to the cooling fan, the second terminal is grounded, and the control terminal is connected to the output terminal of the voltage regulation circuit; one terminal of the fourth resistor R4 is connected to the control terminal of the second switching transistor Q2, and the other terminal is grounded.

[0024] The second capacitor C2 is connected in parallel with the fourth resistor R4.

[0025] This solution uses a second switching transistor Q2 connected in series downstream of the cooling fan for switching control. It requires only a small current to achieve high current conduction control, disconnects the cooling fan when cooling is not needed to avoid power consumption, protects other components in the circuit from the effects of cooling fan failure, and has a fast response function.

[0026] In a further embodiment, the rectifier module includes a second diode D1 and a third capacitor C3. The positive terminal of the second diode D1 is connected to the power supply output circuit of the electrical load, and the negative terminal is connected to the positive terminal of the third capacitor C3, as well as electrically connected to the voltage regulation circuit, the temperature monitoring and speed control module, and the cooling fan. The negative terminal of the third capacitor C3 is grounded.

[0027] This solution sets up a rectifier module in series between the electrical load output circuit and the speed control device, and performs output rectification based on series diodes; a third capacitor C3 is set up to suppress transient high voltage caused by external interference (such as lightning strikes, inductive load switches), protect the downstream circuit, and effectively improve the reliability of the circuit.

[0028] In a further embodiment, the power supply output circuit includes a transformer T1, a third diode D2, and a fourth capacitor C4; the primary winding T1A of the transformer T1 is connected to the input power supply circuit, and the secondary winding T1B is connected to the positive terminal of the third diode D2 and the rectifier module; the negative terminal of the third diode D2 is connected to the electrical load; the positive terminal of the fourth capacitor C4 is connected between the negative terminal of the third diode D2 and the electrical load, and the other end is grounded.

[0029] In this scheme, the output terminal of the secondary winding T1B of transformer T1 in the power supply output circuit of the electrical load is connected to the speed control device of the cooling fan. By detecting the power supply voltage of the power supply output circuit, the connection detection of the electrical load is realized, thereby realizing the intelligent adjustment of the cooling fan. Attached Figure Description

[0030] Figure 1 This is a system framework diagram of a speed control device for a cooling fan provided in Embodiment 2 of this utility model;

[0031] Figure 2 This is the hardware circuit diagram provided in Embodiment 2 of this utility model;

[0032] The components include: voltage regulation circuit 1, load detection module 11, drive module 12; switch module 2, temperature monitoring and speed control module 3, rectifier module 4, electrical load 5, and cooling fan FAN. Detailed Implementation

[0033] The embodiments of this utility model are described in detail below with reference to the accompanying drawings. The embodiments are given for illustrative purposes only and should not be construed as limiting the utility model. The accompanying drawings are for reference and illustration only and do not constitute a limitation on the scope of patent protection of this utility model, because many changes can be made to this utility model without departing from the spirit and scope of this utility model.

[0034] Example 1

[0035] This utility model provides a speed control device for a cooling fan (FAN), such as... Figure 1 , Figure 2As shown, in this embodiment, it includes a voltage regulation circuit 1, a switching module 2, a temperature monitoring and speed control module 3, and a rectifier module 4; the input terminal of the rectifier module 4 is connected to the power supply output circuit of the electrical load, and the output terminal is electrically connected to the voltage regulation circuit 1, the temperature monitoring and speed control module 3, and the cooling fan FAN; the voltage regulation circuit 1 is also connected to the control terminal of the switching module 2; the temperature monitoring and speed control module 3 is installed near the placement position of the electrical load 5 and is connected to the control terminal of the voltage regulation circuit 1; the cooling fan FAN is grounded through the switching module 2.

[0036] In this embodiment, the voltage regulation circuit 1 includes a load detection module 11 and a drive module 12. One end of the load detection module 11 is connected to the rectifier module 4, and the other end is connected to the control terminal of the drive module 12. The input terminal of the drive module 12 is connected to the rectifier module 4, and the output terminal is connected to the control terminal of the switch module 2. The temperature monitoring and speed regulation module 3 is connected to the control terminal of the drive module.

[0037] In this embodiment, the load detection module 11 includes a first diode ZD1 and a first resistor R1;

[0038] The cathode of the first diode ZD1 is connected to the rectifier module 4, and the anode is connected to the control terminal of the drive module through the first resistor R1.

[0039] The first diode ZD1 is a Zener diode.

[0040] In this embodiment, a Zener diode is set as the core of the load detection mechanism. By utilizing its reverse breakdown characteristics, the voltage threshold when the cooling fan FAN is turned on can be set. This voltage is detected from the power supply output circuit of the electrical load 5. Therefore, load self-detection and self-starting control of the cooling fan FAN can be realized, meeting the standby power consumption and average efficiency requirements of Energy Efficiency VI.

[0041] In this embodiment, the driving module 12 includes a first switching transistor Q1, a second resistor R2, a third resistor R3, and a first capacitor C1; the first capacitor C1 is used for noise filtering and can be selected or not used as needed.

[0042] The first terminal of the first switching transistor Q1 is connected to the rectifier module 4 through the second resistor R2, and the second terminal is connected to the control terminal of the switching module 2. The control terminal is connected to the load detection module and the temperature monitoring and speed control module 3.

[0043] One end of the third resistor R3 is connected to the control terminal of the first switch Q1, and the other end is grounded;

[0044] The first capacitor C1 is connected in parallel with the third resistor R3.

[0045] The second switching transistor Q2 includes a P-channel MOSFET and an N-channel MOSFET; in this embodiment, an N-channel MOSFET is preferred, with its first terminal, second terminal, and control terminal being the source, drain, and gate, respectively. Under pure hardware control, the cooling fan FAN will not work if the power supply is not under load. Simultaneously, based on the reverse breakdown characteristics of the Zener diode, the load at which the cooling fan FAN starts can be set, and the fan speed can be intelligently adjusted as the electrical load and temperature increase.

[0046] In this embodiment, a first switching transistor Q1 is set to drive the fan. Its control terminal is connected to a third resistor R3 and a first resistor R1. Based on the voltage division of the resistors, the conduction point of the first switching transistor Q1 can be customized according to the requirements, and then the conduction voltage can be customized, that is, the conduction voltage can be customized to adapt to the load size. The cooling fan FAN can be set to start according to the load state of the electrical load 5. The structure is simple and the design cost is low.

[0047] In this embodiment, the temperature monitoring and speed control module 3 includes a thermistor NTC. One end of the thermistor NTC is connected to the rectifier module 4 or other power supply terminal, and the other end is connected to the control terminal of the switch module 2.

[0048] In this embodiment, a thermistor NTC is placed near the location of the electrical load 5. By connecting the control terminal of its voltage regulation circuit 1, the current value at the control terminal of the first switching transistor Q1 is changed by the change of the resistance value while monitoring the temperature, thereby realizing the self-adjustment of the speed of the cooling fan FAN, which has a high degree of intelligence.

[0049] In this embodiment, the switching module 2 includes a second switching transistor Q2, a fourth resistor R4, and a second capacitor C2;

[0050] The first terminal of the second switching transistor Q2 is connected to the cooling fan FAN, the second terminal is grounded, and the control terminal is connected to the output terminal of the voltage regulation circuit 1; one terminal of the fourth resistor R4 is connected to the control terminal of the second switching transistor Q2, and the other terminal is grounded;

[0051] The second capacitor C2 is connected in parallel with the fourth resistor R4; the second capacitor C2 is used for noise filtering and can be selected or not used as needed.

[0052] The second switching transistor Q2 includes an NPN transistor and a PNP transistor; in this embodiment, it is preferably an NPN transistor, with its first terminal, second terminal, and control terminal being the collector, emitter, and base, respectively.

[0053] In this embodiment, a second switching transistor Q2 is connected in series downstream of the cooling fan FAN for switching control. Only a small current is needed to achieve high current conduction control. When cooling is not required, the cooling fan FAN is disconnected to avoid power consumption. At the same time, it protects other components in the circuit from the impact of cooling fan FAN failure and has a fast response function.

[0054] In this embodiment, the rectifier module 4 includes a second diode D1 and a third capacitor C3, with the positive terminal of the second diode D1 connected to the electrical load 5 (e.g., ...). Figure 2 The power supply output circuit (at the OUT+ and OUT- interfaces) has its negative terminal connected to the positive terminal of the third capacitor C3, and is also electrically connected to the voltage regulation circuit 1, the temperature monitoring and speed control module 3, and the cooling fan FAN; the negative terminal of the third capacitor C3 is grounded.

[0055] In this embodiment, a rectifier module 4 is connected in series between the output circuit of the electrical load 5 and the speed control device, and output rectification is performed based on series diodes; a third capacitor C3 is set to suppress transient high voltage caused by external interference (such as lightning strikes, inductive load switches), protect the downstream circuit, and effectively improve the reliability of the circuit.

[0056] In this embodiment, the power supply output circuit includes a transformer T1, a third diode D2, and a fourth capacitor C4; the primary winding T1A of the transformer T1 is connected to the input power supply circuit, and the secondary winding T1B is connected to the positive terminal of the third diode D2 and the rectifier module 4; the negative terminal of the third diode D2 is connected to the electrical load 5; the positive terminal of the fourth capacitor C4 is connected between the negative terminal of the third diode D2 and the electrical load 5, and the other end is grounded for power filtering.

[0057] Among them, the third capacitor C3 and the fourth capacitor C4 are preferably electrolytic capacitors.

[0058] The second diode D1 and the third diode D2 are both used for circuit rectification. After rectification by the second diode D1, the current is filtered by C3 and supplied to the cooling fan and speed control device. After rectification by the third diode D2, the current is filtered by C4 and supplied to the electrical load 5, so as to better detect whether the electrical load 5 is in a full load / no load / small load state.

[0059] Specifically, when the load 5 increases, the duty cycle of the switching power supply increases to increase output energy. At this time, the voltage in the circuit supplying power to the fan via the second diode D1 will rise (because it shares a common transmission transformer T1, and the load in the second diode D1 circuit is very small; as the duty cycle of transformer T1 increases, the energy obtained by the second diode D1 increases, and the voltage rises). Conversely, when the load 5 decreases, the duty cycle of the switching power supply decreases, and the voltage in the power supply circuit of the second diode D1 decreases. Simultaneously, the output circuit of the third diode D2 in the switching power supply has a voltage regulator circuit, ensuring stable output under different loads (this is a conventional technique in this field and will not be elaborated upon in this embodiment).

[0060] In this embodiment, the output terminal of the secondary winding T1B of the transformer T1 in the power supply output circuit of the electrical load 5 is connected to the speed control device of the cooling fan FAN. By detecting the power supply voltage of the power supply output circuit, the connection detection of the electrical load 5 is realized, thereby realizing the intelligent adjustment of the cooling fan FAN.

[0061] The fan startup principle in this embodiment is as follows:

[0062] The switching power supply of load 5 has a very small duty cycle and transmits little energy when under no-load or light load conditions; however, it has a large duty cycle and transmits a lot of energy when under full load conditions, resulting in a much higher voltage in the power supply output circuit when under full load conditions compared to when under no-load conditions.

[0063] Taking a 12V / 13A switching power supply as an example, the no-load supply voltage is only about 12V, while the full-load voltage can reach 16V or even higher.

[0064] When the output is under load, the first diode ZD1 can detect that the supply voltage is greater than 12V to determine if the output is under load (that is, the first diode ZD1 detects the voltage change caused by the load change to determine when the cooling fan FAN is turned off and when it is turned on). When the first diode ZD1 is turned on, the first switch Q1 is set to conduction point by voltage division through the first resistor R1 and the third resistor R3; the base current of the second switch Q2 is controlled by the first switch Q1 to control the conduction / turn-off of the second switch Q2, thereby realizing the on-time and speed control of the cooling fan FAN.

[0065] Meanwhile, the thermistor NTC is used for temperature monitoring and speed control. When the temperature rises, the resistance of the thermistor NTC decreases, the gate voltage of the first switch Q1 increases, which in turn increases the base current of the second switch Q2 and the speed of the cooling fan FAN increases. Conversely, when the output is unloaded or under a set small load, the first diode ZD1 does not conduct, the first switch Q1 and the second switch Q2 are cut off, and the cooling fan FAN stops working.

[0066] When the electrical load 5 is at half load or a set load (set according to the first diode ZD1, the first resistor R1, and the third resistor R3), the first switching transistor Q1 is turned on with a small current, and the fan runs at a low speed. That is, the cooling fan does not turn when the output is unloaded or under a small load, but turns on or the cooling fan speed increases linearly with the increase of the electrical load 5 or the temperature (the larger the electrical load 5, the faster the speed; the higher the temperature, the faster the speed).

[0067] This embodiment of the invention is based on the heat dissipation requirements of the electrical load 5. A corresponding cooling fan (FAN) is configured to cool the working environment. Therefore, one end of the voltage regulation circuit 1 is connected to the rectifier module 4. By detecting voltage changes, it is determined whether the electrical load 5 is connected, and then the switch module 2 is driven in real time to conduct the power circuit for heat dissipation, so that the cooling fan (FAN) can automatically start. At the same time, a temperature monitoring and speed control module 3 is installed near the placement position of the electrical load 5 and connected to the control terminal of the voltage regulation circuit 1 to provide feedback adjustment of the temperature of the electrical load 5. While meeting the heat dissipation requirements, it also achieves energy saving and noise reduction, meeting the low cost requirements. The cooling fan can be turned off when there is no load in standby mode. The cooling fan runs at low speed under small load and runs at high speed under full load, meeting the green energy saving requirements.

[0068] The above embodiments are preferred embodiments of the present utility model, but the embodiments of the present utility model are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present utility model shall be considered equivalent substitutions and shall be included within the protection scope of the present utility model.

Claims

1. A speed control device for a heat dissipating fan, characterized by: It includes a voltage regulation circuit, a switching module, a temperature monitoring and speed control module, and a rectifier module; the input terminal of the rectifier module is connected to the power supply output circuit of the electrical load, and the output terminal is electrically connected to the voltage regulation circuit, the temperature monitoring and speed control module, and the cooling fan; the voltage regulation circuit is also connected to the control terminal of the switching module; the temperature monitoring and speed control module is installed near the placement position of the electrical load and is connected to the control terminal of the voltage regulation circuit; the cooling fan is grounded through the switching module.

2. The speed control device for a cooling fan as described in claim 1, characterized in that: The voltage regulation circuit includes a load detection module and a drive module. One end of the load detection module is connected to the rectifier module, and the other end is connected to the control terminal of the drive module. The input terminal of the drive module is connected to the rectifier module, and the output terminal is connected to the control terminal of the switch module. The temperature monitoring and speed regulation module is connected to the control terminal of the drive module.

3. The speed control device for a cooling fan as described in claim 2, characterized in that: The load detection module includes a first diode ZD1 and a first resistor R1; The cathode of the first diode ZD1 is connected to the rectifier module, and the anode is connected to the control terminal of the drive module through the first resistor R1. The first diode ZD1 is a Zener diode.

4. The speed control device for a cooling fan as described in claim 3, characterized in that: The driving module includes a first switching transistor Q1, a second resistor R2, a third resistor R3, and a first capacitor C1; The first terminal of the first switching transistor Q1 is connected to the rectifier module through the second resistor R2, and the second terminal is connected to the control terminal of the switching module. The control terminal is connected to the load detection module and the temperature monitoring and speed control module. One end of the third resistor R3 is connected to the control terminal of the first switch Q1, and the other end is grounded; The first capacitor C1 and the third resistor R3.

5. The speed control device for a cooling fan as described in claim 4, characterized in that: The temperature monitoring and speed control module includes a thermistor NTC, one end of which is connected to the rectifier module and the other end is connected to the control terminal of the switch module.

6. The speed control device for a cooling fan as described in claim 1, characterized in that: The switching module includes a second switching transistor Q2, a fourth resistor R4, and a second capacitor C2; The first terminal of the second switching transistor Q2 is connected to the cooling fan, the second terminal is grounded, and the control terminal is connected to the output terminal of the voltage regulation circuit; one terminal of the fourth resistor R4 is connected to the control terminal of the second switching transistor Q2, and the other terminal is grounded. The second capacitor C2 is connected in parallel with the fourth resistor R4.

7. The speed control device for a cooling fan as described in claim 1, characterized in that: The rectifier module includes a second diode D1 and a third capacitor C3. The positive terminal of the second diode D1 is connected to the power supply output circuit of the electrical load, and the negative terminal is connected to the positive terminal of the third capacitor C3, as well as electrically connected to the voltage regulation circuit, the temperature monitoring and speed control module, and the cooling fan. The negative terminal of the third capacitor C3 is grounded.

8. The speed control device for a cooling fan as described in claim 7, characterized in that: The power supply output circuit includes a transformer T1, a third diode D2, and a fourth capacitor C4; the primary winding T1A of the transformer T1 is connected to the input power supply circuit, and the secondary winding T1B is connected to the positive terminal of the third diode D2 and the rectifier module; the negative terminal of the third diode D2 is connected to the electrical load; the positive terminal of the fourth capacitor C4 is connected between the negative terminal of the third diode D2 and the electrical load, and the other end is grounded.

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