Fan with mechanical protection function

Abstract

The utility model provides a fan with mechanical protection, which comprises an over-temperature protection circuit, an over-voltage protection circuit, an over-current protection circuit, a power supply conversion unit and a motor, and is characterized in that the over-voltage protection circuit comprises a comparator, a first switching device and a reference voltage generation circuit comprising a voltage-regulator tube; the over-temperature protection circuit is electrically connected with the motor, the over-current protection circuit is electrically connected with the power conversion unit and the motor, the voltage-regulator tube is electrically connected with a first end of the comparator, a second end of the comparator is electrically connected with the power conversion unit, and the first switching device is electrically connected with a third end of the comparator and the motor. Through the implementation of the utility model, the hardware level of the fan is improved, and when the fan is abnormal, the driving power supply can be cut off through mechanical protection, so that the product is prevented from being burnt, and the stability and the reliability are high.

Description

Technical Field

[0001] The utility model relates to the technical field of electrical appliances, in particular to a fan with mechanical protection. Background Art

[0002] Most electrical devices (such as household appliances, electronic products, digital computers, etc.) are usually equipped with cooling fans, which can be divided into AC fans, DC fans and EC fans. Among them, AC fans are AC cooling fans, DC fans and EC fans are both DC cooling fans, but DC fans input DC power, while EC fans can input AC power. The internal control board rectifies the input AC power into DC power to power the fan motor. Compared with traditional AC fans, EC fans have the characteristics of high efficiency, fast speed, large air volume and more energy saving, so they have been widely used in many applications.

[0003] Most fans in related technologies use software control to achieve fan speed regulation and protection of various operating states. However, once the software program fails or the software controller is subject to electromagnetic interference, the software protection function may fail, causing the fan to overload and be damaged, or even cause a safety accident. Utility Model Content

[0004] The utility model provides a fan with mechanical protection, aiming to solve the problem that the protection method controlled by software in the related technology has certain potential safety hazards.

[0005] In order to solve the above technical problems, the first aspect of the utility model provides a fan with mechanical protection, including: an over-temperature protection circuit, an over-voltage protection circuit, an over-current protection circuit, a power conversion unit and a motor, the over-voltage protection circuit including a comparator, a first switching device and a reference voltage generating circuit including a voltage regulator; the over-temperature protection circuit is electrically connected to the motor, the over-current protection circuit is electrically connected to the power conversion unit and the motor respectively, the voltage regulator is electrically connected to the first end of the comparator, the second end of the comparator is electrically connected to the power conversion unit, and the first switching device is electrically connected to the third end of the comparator and the motor respectively.

[0006] Furthermore, the reference voltage generating circuit also includes a first voltage divider circuit and a first resistor, the first voltage divider circuit is electrically connected to a power supply, one end of the first resistor is electrically connected to the first voltage divider circuit, the other end of the first resistor is respectively electrically connected to the first end of the Zener diode and the first end of the comparator, the second end of the Zener diode is electrically connected to the first end of the comparator, and the third end of the Zener diode is grounded.

[0007] Furthermore, the first voltage divider circuit includes a second resistor and a third resistor, the second resistor is electrically connected to a power supply and one end of the third resistor respectively, the other end of the third resistor is grounded, and a common connection end of the second resistor and the third resistor is electrically connected to the first resistor.

[0008] Furthermore, the overvoltage protection circuit also includes a second voltage divider circuit and a fourth resistor, one end of the second voltage divider circuit is electrically connected to the second end of the comparator, the other end of the second voltage divider circuit is used to be electrically connected to the power conversion unit, the fourth resistor is respectively electrically connected to the third end of the comparator and the gate of the first switching device, the drain of the first switching device is electrically connected to the motor, and the source of the first switching device is grounded.

[0009] Furthermore, the second voltage divider circuit includes a fifth resistor and a sixth resistor, the fifth resistor is electrically connected to one end of the sixth resistor and the power conversion unit respectively, the other end of the sixth resistor is grounded, and the common connection end of the fifth resistor and the sixth resistor is electrically connected to the second end of the comparator.

[0010] Furthermore, the over-temperature protection circuit includes a temperature switch, and the temperature switch is electrically connected to the winding of the motor.

[0011] Furthermore, the over-temperature protection circuit includes a thermostat, and the thermostat is used to be electrically connected between the power conversion unit and the motor.

[0012] Furthermore, the overcurrent protection circuit includes a fuse, and the fuse is used to be electrically connected between the power conversion unit and the motor.

[0013] From the above description, it can be seen that the utility model improves the hardware level of the fan, that is, adds an overvoltage protection circuit, an overcurrent protection circuit and an overtemperature protection circuit including semiconductor switch devices to the circuit control board of the fan. When the fan is abnormal, it can cut off the driving power supply through mechanical protection, thereby protecting the product from burning. Compared with software protection, mechanical protection will not fail due to errors in the software code or damage to the software control program, so it is more stable and reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a structural schematic diagram of a fan with mechanical protection according to an embodiment of the utility model;

[0015] Figure 2 It is a circuit principle diagram of a reference voltage generating circuit of an embodiment of the utility model;

[0016] Figure 3This is a circuit schematic diagram of an overvoltage protection circuit in an embodiment of the utility model;

[0017] Figure 4 The utility model is a circuit diagram of an overcurrent protection circuit according to an embodiment of the present invention. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical scheme and advantages of the utility model clearer, the utility model is further described in detail below in conjunction with the accompanying drawings and embodiments, wherein the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. It should be understood that the specific embodiments described herein are only used to explain the utility model and are not used to limit the utility model. In addition, the technical features involved in the various embodiments of the utility model described below can be combined with each other as long as they do not conflict with each other.

[0019] In the related art, there is a problem that the protection method controlled by software has certain potential safety hazards. Therefore, the embodiment of the utility model provides a fan with mechanical protection.

[0020] like Figure 1 The structure diagram of a fan with mechanical protection provided by an embodiment of the utility model is shown, and the fan with mechanical protection includes: an over-temperature protection circuit 100, an over-voltage protection circuit 200, an over-current protection circuit 300, a power conversion unit 400 and a motor 500, the over-voltage protection circuit 200 includes a comparator 210, a first switch device 220 and a reference voltage generation circuit 230 including a voltage regulator 231; the over-temperature protection circuit 100 is electrically connected to the motor 500, the over-current protection circuit 300 is electrically connected to the power conversion unit 400 and the motor 500, the voltage regulator 231 is electrically connected to the first end of the comparator 210, the second end of the comparator 210 is electrically connected to the power conversion unit 400, and the first switch device 220 is electrically connected to the third end of the comparator 210 and the motor 500. The fan can be an EC fan.

[0021] Specifically, this embodiment improves the hardware level of the fan, that is, adds an overvoltage protection circuit 200, an overcurrent protection circuit 300 and an overtemperature protection circuit 100 including semiconductor switch devices to the circuit control board of the fan. When the fan is abnormal, the driving power supply can be cut off through mechanical protection, thereby protecting the product from burning. Compared with software protection, mechanical protection will not fail due to errors in the software code or damage to the software control program, and is therefore more stable and reliable.

[0022] Furthermore, in an implementation of this embodiment, the over-temperature protection circuit 100 includes a temperature switch, and the temperature switch is electrically connected to the winding of the motor 500 .

[0023] Furthermore, in another implementation of this embodiment, the over-temperature protection circuit 100 includes a thermostat, which is electrically connected between the power conversion unit 400 and the motor 500 .

[0024] Specifically, under normal circumstances, the windings of the motor 500 have a temperature range. When the temperature of the motor windings is too high, it will directly affect the normal operation of the motor. In severe cases, it will affect the life of the motor. In more severe cases, it will directly burn the motor, causing unnecessary risks and losses. In this embodiment, an over-temperature protection circuit 100 is set on the windings of the motor to achieve mechanical motor protection. The over-temperature protection circuit 100 can be specifically protected by a temperature switch. The temperature switch fits tightly with the motor windings to detect the winding temperature. When the temperature of the motor windings is normal, the temperature switch is turned on and the motor can work normally; when the temperature of the motor windings is too high and reaches the disconnection temperature threshold of the temperature switch, the temperature switch is disconnected, thereby cutting off the connection between the motor and the power supply, and the motor stops; wherein, the temperature switch can also be a temperature control switch with a single temperature protection, or a temperature control switch with dual protection of temperature and current, such as a temperature control switch with model 6APSR415A099. In addition, the over-temperature protection circuit 100 can also be protected by a thermostat, which can automatically adjust the working state of the fan according to the temperature change of the environment or system to keep the temperature within a set range. The thermostat usually includes a temperature sensor, a control circuit and an output control device. When the temperature sensor detects that the ambient temperature exceeds the preset range, the control circuit will send a signal to stop the fan to adjust the temperature.

[0025] like Figure 2 FIG. 1 is a circuit schematic diagram of a reference voltage generating circuit provided in this embodiment, see Figure 2 The reference voltage generating circuit 230 also includes a first voltage divider circuit 232 and a first resistor R1. The first voltage divider circuit 232 is electrically connected to a power supply. One end of the first resistor R1 is electrically connected to the first voltage divider circuit 232. The other end of the first resistor R1 is electrically connected to the first end of the voltage regulator tube 231 (IC1) and the first end of the comparator 210 respectively. The second end of the voltage regulator tube IC1 is electrically connected to the first end of the comparator IC2-A. The third end of the voltage regulator tube IC1 is grounded.

[0026] Furthermore, the first voltage divider circuit 232 includes a second resistor R2 and a third resistor R3, the second resistor R2 is electrically connected to the power supply and one end of the third resistor R3 respectively, the other end of the third resistor R3 is grounded, and the common connection end of the second resistor R2 and the third resistor R3 is electrically connected to the first resistor R1.

[0027] like Figure 3FIG. 1 is a circuit diagram of an overvoltage protection circuit provided in this embodiment. Figure 3 The overvoltage protection circuit 200 also includes a second voltage divider circuit 233 and a fourth resistor R4. One end of the second voltage divider circuit 233 is electrically connected to the second end of the comparator 210 (IC2-A), and the other end of the second voltage divider circuit 233 is electrically connected to the power conversion unit 400. The fourth resistor R4 is electrically connected to the third end of the comparator IC2-A and the gate of the first switching device Q1 respectively. The drain of the first switching device Q1 is electrically connected to the motor 500, and the source of the first switching device Q1 is grounded.

[0028] Furthermore, the second voltage divider circuit 233 includes a fifth resistor R5 and a sixth resistor R6, the fifth resistor R5 is electrically connected to one end of the sixth resistor R6 and the power conversion unit 400 respectively, the other end of the sixth resistor R6 is grounded, and the common connection end of the fifth resistor R5 and the sixth resistor R6 is electrically connected to the second end of the comparator IC2-A.

[0029] Specifically, in an EC fan, when the input AC power is connected to the PCB board of the EC fan, the power conversion unit 400 on the PCB board converts the voltage from AC power to the required DC power, and then transmits the DC power to the fan motor, so that the fan rotates. If the power conversion unit 400 fails, it is possible to directly burn the fan motor. In this embodiment, an overvoltage protection circuit 200 is added to the DC output end of the power conversion unit 400, and then the electric energy flowing to the motor is controlled by the first switch device Q1 such as a MOS tube. When the overvoltage protection circuit 200 detects that the DC voltage output by the power conversion unit 400 is the required DC voltage, the MOS tube is turned on by a voltage, so that the MOS tube is turned on and the DC voltage flows to the fan motor; on the contrary, if it is detected that the DC voltage is not the required DC voltage, the MOS tube is turned off by a voltage, and the MOS tube is in a disconnected state at this time, and the DC power will not flow to the fan motor, thereby playing a role in mechanically protecting the motor 500.

[0030] More specifically, in the present embodiment, the overvoltage protection circuit 200 generates a reference voltage such as 2.5V by the voltage regulator IC1, and sends it to the in-phase port of the comparator IC2-A. The power conversion unit 400 is sent to the inverting end of the comparator after voltage division by the fifth resistor R5 and the sixth resistor R6. When the voltage output by the power conversion unit 400 is less than the preset value, such as 48V, the comparator IC2-A outputs a high-level signal, the gate of the first switch device Q1 receives the high-level signal, and the first switch device Q1 is turned on. At this time, the path between the power conversion unit 400 and the motor 500 is turned on, and the power output terminal POWER-OUT has 48V DC output to the motor 500. When the voltage output by the power conversion unit 400 is greater than the preset value, such as 48V, the comparator IC2-A outputs a low-level signal, the gate of the first switch device Q1 receives the low-level signal, and the first switch device Q1 is turned off. At this time, there is no 48V DC output.

[0031] like Figure 4 FIG. 1 is a circuit diagram of an overcurrent protection circuit provided in this embodiment. Figure 4 The overcurrent protection circuit 300 includes a second switch device Q2, a transistor Q3 and a sampling resistor R7. The drain of the second switch device Q2 is electrically connected to the power conversion unit 400, the source of the second switch device Q2 is electrically connected to one end of the sampling resistor R7, the other end of the sampling resistor R7 is grounded, the gate of the second switch device Q2 is electrically connected to the collector of the transistor Q3, the base of the transistor Q3 is electrically connected to one end of the sampling resistor R7, and the emitter of the transistor Q3 is grounded.

[0032] In addition, in one implementation of this embodiment, the overcurrent protection circuit 300 includes a fuse, which is electrically connected between the power conversion unit 400 and the motor 500 .

[0033] Specifically, in an EC fan, when the motor 500 is stuck or in other abnormal conditions, the current will increase rapidly and instantly, resulting in a large amount of heat generation, which may cause damage to components and, in severe cases, may cause a fire accident due to excessive temperature. This embodiment adds an overcurrent protection circuit 300 to the circuit that supplies power to the motor 500 to achieve the function of mechanically protecting the motor 500. The overtemperature protection circuit 100 can specifically be protected by a fuse. When an abnormal current increases, the fuse temperature will increase, and the power supply will be cut off when the fuse temperature threshold is reached. In addition, the overcurrent protection circuit 300 can also be implemented through a topological structure of a switching device, a transistor Q3 and a sampling resistor R7, wherein the sampling voltage of the sampling resistor R7 can be used as a driving voltage of the transistor Q3. When the fan is operating normally, the voltage on the sampling resistor R7 is lower than the turn-on voltage of the transistor Q3, the transistor Q3 is disconnected, and the second switching device Q2, such as a MOS tube, is turned on. At this time, the fan can obtain electrical energy; when an overcurrent occurs in the circuit, the voltage of the sampling resistor R7 will be higher than the turn-on voltage of the transistor Q3, the transistor Q3 is turned on, the gate of the MOS tube is pulled down, and the MOS tube is turned off, thereby controlling the fan to stop working to avoid damage to the fan due to long-term overcurrent operation.

[0034] The fan with mechanical protection provided by the embodiment of the utility model is improved at the hardware level of the fan, that is, an overvoltage protection circuit, an overcurrent protection circuit and an overtemperature protection circuit including semiconductor switch devices are added to the circuit control board of the fan. When the fan is abnormal, the driving power supply can be cut off through mechanical protection, thereby protecting the product from burning. Compared with software protection, mechanical protection will not cause protection failure due to errors in software code or damage to the software control program, so it is more stable and reliable.

[0035] It should be noted that the various embodiments in the present invention are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same and similar parts between the various embodiments can be referenced to each other.

[0036] It should also be noted that, in the present invention, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise one..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0037] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined in the present invention may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown in the present invention, but will conform to the widest range consistent with the principles and novel features disclosed in the present invention.

Claims

1. A fan with mechanical protection, characterized in that: include: An over-temperature protection circuit, an over-voltage protection circuit, an over-current protection circuit, a power conversion unit and a motor, wherein the over-voltage protection circuit includes a comparator, a first switching device and a reference voltage generating circuit including a voltage regulator tube; The over-temperature protection circuit is electrically connected to the motor, the over-current protection circuit is electrically connected to the power conversion unit and the motor respectively, the voltage regulator is electrically connected to the first end of the comparator, the second end of the comparator is electrically connected to the power conversion unit, and the first switch device is electrically connected to the third end of the comparator and the motor respectively; The reference voltage generating circuit also includes a first voltage divider circuit and a first resistor, the first voltage divider circuit is electrically connected to a power supply, one end of the first resistor is electrically connected to the first voltage divider circuit, the other end of the first resistor is electrically connected to the first end of the voltage regulator tube and the first end of the comparator respectively, the second end of the voltage regulator tube is electrically connected to the first end of the comparator, and the third end of the voltage regulator tube is grounded.

2. The fan according to claim 1, characterized in that The first voltage divider circuit includes a second resistor and a third resistor, the second resistor is electrically connected to a power supply and one end of the third resistor respectively, the other end of the third resistor is grounded, and a common connection end of the second resistor and the third resistor is electrically connected to the first resistor.

3. The fan according to claim 1, characterized in that: The overvoltage protection circuit also includes a second voltage divider circuit and a fourth resistor, one end of the second voltage divider circuit is electrically connected to the second end of the comparator, the other end of the second voltage divider circuit is used to be electrically connected to the power conversion unit, the fourth resistor is electrically connected to the third end of the comparator and the gate of the first switching device respectively, the drain of the first switching device is electrically connected to the motor, and the source of the first switching device is grounded.

4. The fan according to claim 3, characterized in that: The second voltage divider circuit includes a fifth resistor and a sixth resistor, the fifth resistor is electrically connected to one end of the sixth resistor and the power conversion unit respectively, the other end of the sixth resistor is grounded, and the common connection end of the fifth resistor and the sixth resistor is electrically connected to the second end of the comparator.

5. The fan according to claim 1, characterized in that: The over-temperature protection circuit includes a temperature switch, and the temperature switch is electrically connected to the winding of the motor.

6. The fan according to claim 1, characterized in that: The over-temperature protection circuit includes a thermostat, and the thermostat is used to be electrically connected between the power conversion unit and the motor.

7. The fan according to claim 1, characterized in that: The overcurrent protection circuit includes a fuse, and the fuse is used to be electrically connected between the power conversion unit and the motor.

8. The fan according to claim 1, characterized in that The overcurrent protection circuit includes a second switch device, a transistor and a sampling resistor, the drain of the second switch device is electrically connected to the power conversion unit, the source of the second switch device is electrically connected to one end of the sampling resistor, the other end of the sampling resistor is grounded, the gate of the second switch device is electrically connected to the collector of the transistor, the base of the transistor is electrically connected to one end of the sampling resistor, and the emitter of the transistor is grounded.

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