Motor moisture-proof circuit and fan

Abstract

The motor moisture-proof circuit comprises a temperature and humidity detection circuit, a main control circuit, a heating circuit and a first switching circuit, the temperature and humidity detection circuit is used for detecting the temperature and humidity of the environment and outputting corresponding detection signals, and the main control circuit is electrically connected with the output end of the temperature and humidity detection circuit. The input end of the first switching circuit is electrically connected with the power supply end, the output end of the first switching circuit is electrically connected with the power supply end of the heating circuit, and the controlled end of the first switching circuit is electrically connected with the main control circuit.

Description

Technical Field

[0001] The utility model relates to the technical field of motor control, in particular to a motor moisture-proof circuit and a fan. Background Art

[0002] Hair dryers mainly rely on heat energy to dry hair. They are usually composed of a motor, a heating element and a casing. Their working principle is to use a motor to drive a fan to blow out the hot air in the heating element to dry the hair. However, in a high-humidity environment such as a bathroom, rainy season or at the seaside, water vapor in the air will enter the interior of the hair dryer and cause the hair dryer's circuit to become damp, which can make the hair dryer prone to various malfunctions and safety hazards. Utility Model Content

[0003] The main purpose of the utility model is to provide a motor moisture-proof circuit, aiming to enable the fan to be used normally in a high humidity environment.

[0004] To achieve the above purpose, the motor moisture-proof circuit proposed by the utility model is applied to a fan, comprising:

[0005] A temperature and humidity detection circuit, which is used to detect the temperature and humidity of the environment and output a corresponding detection signal;

[0006] A main control circuit, the main control circuit is electrically connected to the output end of the temperature and humidity detection circuit to receive the detection signal;

[0007] Heating circuit;

[0008] a first switch circuit, wherein an input end of the first switch circuit is electrically connected to a power supply end, an output end of the first switch circuit is electrically connected to a power supply end of the heating circuit, and a controlled end of the first switch circuit is electrically connected to the main control circuit;

[0009] The main control circuit is used to control the operation of the first switch circuit according to the detection signal, so that the power supply end outputs a corresponding current to the heating circuit through the first switch circuit.

[0010] Optionally, the first switch circuit includes:

[0011] A first switch tube, a first photocoupler, a first resistor, a second resistor, a third resistor and a fourth resistor, wherein the first photocoupler includes a first phototransistor and a first photodiode, the input end of the first switch tube is electrically connected to the power supply end, the output end of the first switch tube is electrically connected to the heating circuit and the first end of the first resistor respectively, the controlled end of the first switch tube is electrically connected to the output end of the first phototransistor, the second end of the first resistor is electrically connected to the first end of the second resistor, the second end of the second resistor is electrically connected to the input end of the first phototransistor, the input end of the first photodiode and the first end of the third resistor are both used to access a first voltage, the output end of the first photodiode is electrically connected to the second end of the third resistor and the first end of the fourth resistor respectively, and the second end of the fourth resistor is electrically connected to the main control circuit.

[0012] Optionally, the heating circuit includes at least one heating wire, and at least one of the heating wires is electrically connected to an output end of the first switching circuit.

[0013] Optionally, the motor moisture-proof circuit further includes:

[0014] A second switch circuit and a motor coil, wherein the input end of the second switch circuit is used to access the power supply end, and the output end of the second switch circuit is electrically connected to the motor coil; the controlled end of the second switch circuit is electrically connected to the main control circuit, and the main control circuit is used to control the operation of the second switch circuit according to the detection signal, so that the power supply end outputs a corresponding current to the motor coil through the first switch circuit.

[0015] Optionally, the motor moisture-proof circuit includes multiple second switching circuits, the motor coil includes a Y-type motor coil, the Y-type motor coil includes a first coil, a second coil and a third coil, and the output ends of the multiple second switching circuits are respectively electrically connected to the first coil of the Y-type motor coil, the second coil of the Y-type motor coil and the third coil of the Y-type motor coil.

[0016] Optionally, the second switch circuit includes:

[0017] a second switch tube, a third switch tube, a fifth resistor, a sixth resistor and a first capacitor, wherein the input end of the second switch tube is used to connect to the power supply end, the output end of the second switch tube is electrically connected to the input end of the third switch tube and the first coil, the second coil or the third coil of the Y-shaped motor coil respectively, the output end of the third switch tube is grounded, and the controlled end of the second switch tube and the controlled end of the third switch tube are both electrically connected to the main control circuit; the first end of the fifth resistor is electrically connected to the controlled end of the second switch tube, the second end of the fifth resistor is electrically connected to the output end of the second switch tube, the first end of the sixth resistor is electrically connected to the controlled end of the third switch tube, and the second end of the sixth resistor is electrically connected to the output end of the third switch tube; the first end of the first capacitor is used to connect to the first voltage, and the second end of the first capacitor is grounded.

[0018] Optionally, the motor moisture-proof circuit further includes:

[0019] A zero-crossing detection circuit and a rectifier bridge circuit, wherein the first end of the rectifier bridge circuit is used to access the live wire, the second end of the rectifier bridge circuit is electrically connected to the power supply end, the third end of the rectifier bridge circuit is used to access the neutral wire, and the fourth end of the rectifier bridge circuit is grounded; the detection end of the zero-crossing detection circuit is electrically connected to the first end of the rectifier bridge circuit, the output end of the zero-crossing detection circuit is electrically connected to the main control circuit, and the zero-crossing detection circuit is used to detect the voltage of the first end of the rectifier bridge circuit and output a corresponding zero-crossing detection signal to the main control circuit.

[0020] Optionally, the zero-crossing detection circuit includes:

[0021] A second photocoupler, a seventh resistor, an eighth resistor and a second capacitor, the second photocoupler includes a second phototransistor and a second photodiode, the input end of the second phototransistor is electrically connected to the second end of the seventh resistor, the first end of the seventh resistor is electrically connected to the first end of the rectifier bridge circuit, and the output end of the second phototransistor is electrically connected to the third end of the rectifier bridge circuit; the input ends of the second photodiode are respectively electrically connected to the second end of the eighth resistor, the second end of the eighth resistor is electrically connected to the first end of the second capacitor, the first end of the second capacitor is electrically connected to the main control circuit, the first end of the eighth resistor is used to access the first voltage, and the output end of the second photodiode and the second end of the second capacitor are both grounded; wherein the zero-crossing detection signal includes the first voltage.

[0022] A fan comprises the motor moisture-proof circuit described in any one of the above items.

[0023] The technical solution of the utility model includes a temperature and humidity detection circuit, a main control circuit, a heating circuit and a first switch circuit. The temperature and humidity detection circuit is used to detect the temperature and humidity of the environment and output a corresponding detection signal. The main control circuit is used to control the operation of the first switch circuit according to the detection signal, so that the power supply end outputs a corresponding current to the heating circuit through the first switch circuit. The greater the current output to the heating circuit, the greater the heat emitted by the heating circuit. With such an arrangement, in actual applications, a hair dryer provided with the motor moisture-proof circuit of the utility model can be used in high humidity environments such as bathrooms, rainy seasons, foggy days or at the seaside. When the hair dryer is in a high humidity environment, the heating circuit emits a large amount of heat, thereby quickly evaporating the water vapor entering around the internal circuit board of the hair dryer to keep the inside of the hair dryer dry. For users, there is no need to worry about the hair dryer getting damp and being damaged in a humid environment, thereby improving the user experience and extending the service life of the hair dryer. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0025] Figure 1 This is a module schematic diagram of an embodiment of the motor moisture-proof circuit of the utility model;

[0026] Figure 2 This is a circuit diagram of another embodiment of the motor moisture-proof circuit of the utility model;

[0027] Figure 3 This is a circuit diagram of another embodiment of the motor moisture-proof circuit of the utility model;

[0028] Figure 4 This is a circuit diagram of another embodiment of the motor moisture-proof circuit of the utility model.

[0029] Description of Figure Numbers:

[0030] Label name Label name 10 Temperature and humidity detection circuit 60 Y-type motor coil 20 Main control circuit 70 Zero Crossing Detection Circuit 30 Heating circuit 80 Rectifier bridge circuit 40 First switch circuit 50 Second switch circuit 51 Fast shutdown circuit

[0031] The realization of the purpose, functional features and advantages of the utility model will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0033] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back...) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0034] In addition, the descriptions of "first", "second", etc. in the present utility model are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present utility model.

[0035] Hair dryers mainly rely on heat energy to dry hair. They are usually composed of a motor, a heating element and a casing. Their working principle is to use a motor to drive a fan to blow out the hot air in the heating element to dry the hair. However, in a high-humidity environment such as a bathroom, rainy season or at the seaside, water vapor in the air will enter the interior of the hair dryer and cause the hair dryer's circuit to become damp, which can make the hair dryer prone to various malfunctions and safety hazards.

[0036] To this end, the utility model proposes a motor moisture-proof circuit, aiming to enable the fan to be used normally in a high humidity environment.

[0037] refer to Figure 1 , a motor moisture-proof circuit, applied to a fan, comprising:

[0038] A temperature and humidity detection circuit 10, wherein the temperature and humidity detection circuit 10 is used to detect the temperature and humidity of the environment and output a corresponding detection signal;

[0039] A main control circuit 20, the main control circuit 20 is electrically connected to the output end of the temperature and humidity detection circuit 10 to receive the detection signal;

[0040] Heating circuit 30;

[0041] a first switch circuit 40, wherein an input end of the first switch circuit 40 is electrically connected to a power supply end, an output end of the first switch circuit 40 is electrically connected to a power supply end of the heating circuit 30, and a controlled end of the first switch circuit 40 is electrically connected to the main control circuit 20;

[0042] The main control circuit 20 is used to control the first switch circuit 40 to work according to the detection signal, so that the power supply end outputs a corresponding current to the heating circuit 30 through the first switch circuit 40 .

[0043] In this embodiment, optionally, the temperature and humidity detection circuit 10 may be a circuit composed of a temperature and humidity sensor and a plurality of discrete components.

[0044] In this embodiment, optionally, the main control circuit 20 can be implemented by a main controller, such as an MCU (Microcontroller Unit), a DSP (Digital Signal Process), an FPGA (Field Programmable Gate Array), a SOC (System OnChip), etc.

[0045] In this embodiment, optionally, the first switch circuit 40 can be implemented by using at least one switch tube, such as a MOS tube, an IGBT tube, a thyristor, a triode, a power tube, etc.

[0046] In this embodiment, optionally, the heating circuit 30 includes at least one heating wire, which can be evenly distributed on the surface or around the circuit board in the fan so that the circuit board can be evenly heated and thus remain dry in a high humidity environment. The heating wire can also be distributed at the air outlet of the fan so that the fan can blow out hot air. The heating wire is usually made of a resistive material, which will generate heat when current passes through it, thereby generating heat. The greater the current flowing through the heating wire, the greater the heat released by the heating wire.

[0047] Specifically, the temperature and humidity detection circuit 10 is used to detect the temperature and humidity of the environment and output a corresponding detection signal. The main control circuit 20 is used to obtain the humidity of the current environment according to the detection signal, and control the operation of the first switch circuit 40 according to the humidity of the current environment. For example, the main control circuit 20 outputs a PWM control signal with a corresponding duty cycle according to the current environmental humidity to control the on-off time of the first switch circuit 40, so that the power supply end outputs a corresponding current to the heating circuit 30 through the first switch circuit 40. The higher the humidity of the current environment, the greater the current output to the heating circuit 30, and the greater the heat emitted by the heating circuit 30. With such a configuration, in actual applications, a hair dryer provided with the motor moisture-proof circuit of the utility model can be used in high humidity environments such as bathrooms, rainy seasons, foggy days or at the seaside. When the hair dryer is in a high humidity environment, the heating circuit 30 releases a large amount of heat, thereby quickly evaporating the water vapor entering the circuit board inside the hair dryer to keep the inside of the hair dryer dry. For users, there is no need to worry about the hair dryer getting damp and damaged in a humid environment, and the service life of the hair dryer is also extended.

[0048] In this embodiment, the main control circuit 20 is also used to obtain the temperature of the current environment based on the detection signal, and control the operation of the first switch circuit 40 according to the temperature of the current environment. When the temperature of the current environment is high, the main control circuit 20 can output a PWM control signal with a lower duty cycle to the first switch circuit 40, so that the on time of the first switch circuit 40 becomes shorter and the off time becomes longer, and the current flowing to the heating circuit 30 also becomes smaller. With such a setting, in actual applications, when a user uses a hair dryer equipped with the motor moisture-proof circuit of the utility model in a high temperature environment, the main control circuit 20 will control the heat released by the heating circuit 30 to become smaller, so that the temperature of the wind it blows out is milder, thereby improving the user's comfort.

[0049] refer to Figure 2 In one embodiment of the present utility model, the first switch circuit 40 includes:

[0050] A first switch tube M1, a first photocoupler D1, a first resistor R1, a second resistor R2, a third resistor R3 and a fourth resistor R4, wherein the first photocoupler D1 includes a first phototransistor and a first photodiode, an input end of the first switch tube M1 is electrically connected to a power supply end, an output end of the first switch tube M1 is electrically connected to the heating circuit 30 and a first end of the first resistor R1 respectively, a controlled end of the first switch tube M1 is electrically connected to an output end of the first phototransistor, a second end of the first resistor R1 is electrically connected to a first end of the second resistor R2, a second end of the second resistor R2 is electrically connected to an input end of the first phototransistor, an input end of the first photodiode and a first end of the third resistor R3 are both used to access a first voltage, an output end of the first photodiode is electrically connected to a second end of the third resistor R3 and a first end of the fourth resistor R4 respectively, and a second end of the fourth resistor R4 is electrically connected to the main control circuit 20.

[0051] In this embodiment, the first switch tube M1 can be a MOS tube, a triode, an IGBT tube or a bidirectional thyristor.

[0052] In this embodiment, the main control circuit 20 controls the voltage of the fourth resistor R4 according to the detection signal, thereby controlling the conduction degree of the photodiode and the light intensity emitted by the photodiode. The larger the voltage of the fourth resistor R4, the lower the conduction degree of the photodiode and the weaker the light emitted by the photodiode. The smaller the voltage of the fourth resistor R4, the greater the conduction degree of the photodiode and the stronger the light emitted by the photodiode. The conduction degree of the phototransistor is proportional to the light intensity emitted by the photodiode, and the conduction degree of the first switch tube M1 and the phototransistor are also proportional. The greater the conduction degree of the first switch tube M1, the greater the current flowing to the heating circuit 30, and the lower the conduction degree of the first switch tube M1, the lower the current flowing to the heating circuit 30. With such a configuration, in actual applications, for example, when a user uses a hair dryer in the bathroom after taking a shower, the main control circuit 20 controls the voltage of the fourth resistor R4, for example, outputs a lower voltage signal to the fourth resistor R4 to the second end of the fourth resistor R4, so that the voltage of the fourth resistor R4 becomes lower. At this time, the conduction degree of the photodiode becomes higher, and the light it emits also becomes stronger. After receiving the light of the photodiode, the conduction degree of the phototransistor also becomes higher, and the conduction degree of the first switch tube M1 also becomes higher. The current flowing through the first switch tube M1 to the heating circuit 30 becomes larger. At this time, the heating circuit 30 releases more heat to evaporate the water vapor in the hair dryer, thereby keeping the inside of the hair dryer dry, so as to achieve the purpose of the hair dryer being able to work normally in a humid environment.

[0053] In one embodiment of the utility model, the motor moisture-proof circuit further includes:

[0054] A second switch circuit 50 and a motor coil, wherein the input end of the second switch circuit 50 is used to connect to the power supply end, and the output end of the second switch circuit 50 is electrically connected to the motor coil; the controlled end of the second switch circuit 50 is electrically connected to the main control circuit 20, and the main control circuit 20 is used to control the operation of the second switch circuit 50 according to the detection signal, so that the power supply end outputs a corresponding current to the motor coil through the first switch circuit 40.

[0055] In this embodiment, optionally, the second switch circuit 50 can be implemented by using at least one switch tube, such as a MOS tube, an IGBT tube, a thyristor, a triode, a power tube, etc.

[0056] In this embodiment, the main control circuit 20 controls the conduction degree of the second switch circuit 50 according to the detection signal, thereby controlling the current flowing to the motor coil. The larger the current flowing to the motor coil, the faster the motor rotates; the smaller the current flowing to the motor coil, the smaller the motor rotates. With such a setting, in actual application, when a user uses a hair dryer with a motor moisture-proof circuit of the utility model in rainy weather, due to the high humidity of the user's environment, the main control circuit 20 controls the conduction degree of the second switch circuit 50 according to the detection signal to increase, so that the current flowing to the motor coil increases, and the motor speed in the hair dryer is increased, thereby blowing out the water vapor in the hair dryer. For the user, there is no need to worry about the hair dryer getting damp and damaged in a humid environment. When using the hair dryer in the bathroom, the wind blown out by the hair dryer automatically increases with the increase of the humidity of the surrounding environment, and can quickly dry the user's wet hair. When used in rainy weather, it can quickly dry wet clothes, thereby improving the user's experience.

[0057] refer to Figure 3 In one embodiment of the utility model, the motor moisture-proof circuit includes a plurality of second switch circuits 50, the motor coil includes a Y-type motor coil 60, the Y-type motor coil 60 includes a first coil, a second coil and a third coil, and the output ends of the plurality of second switch circuits 50 are electrically connected to the first end of the Y-type motor coil 60, the second end of the Y-type motor coil 60 and the third end of the Y-type motor coil 60, respectively.

[0058] In this embodiment, the first coil U, the second coil W and the third coil V of the Y-type motor coil 60 are electrically connected to the output ends of the corresponding second switch circuits 50, respectively. The main control circuit 20 controls the power-on of each coil by controlling the on / off of the plurality of second switch circuits 50, for example, the current at the power supply end is controlled to flow into the Y-type motor coil 60 through one of the coils first, and then flow out of the Y-type motor coil 60 through another coil, so that a magnetic field change is generated between each coil, thereby effectively converting the electric energy at the power supply end into mechanical energy to drive the motor to rotate; the greater the current passing through the coil, the stronger the magnetic field generated, and the faster the motor rotates; therefore, the main control circuit 20 can control the switching speed of the second switch circuit 50 by outputting a PWM signal, so that the coil is repeatedly in a power-on and power-off state; the greater the duty cycle of the PWM signal, the longer the power-on time of the coil, the greater the equivalent voltage at both ends of the coil, the stronger the magnetic field strength generated, and the faster the motor rotates; the smaller the duty cycle of the PWM signal, the shorter the power-on time of the coil, the smaller the equivalent voltage at both ends of the coil, the weaker the magnetic field strength generated, and the slower the motor rotates. For example, when a user uses a hair dryer equipped with the motor moisture-proof circuit of the utility model in the bathroom, the duty cycle of the PWM signal output by the main control circuit 20 to the controlled end of the corresponding second switch circuit 50 becomes larger, so that the conduction time of the second switch circuit 50 becomes longer, and the power-on time of the Y-shaped motor coil 60 also becomes longer, so that the speed of the motor is increased, and finally the air volume blown out by the hair dryer becomes larger, thereby blowing out the water vapor in the hair dryer. For the user, the wet hair can be dried quickly without having to operate the gear position of the hair dryer by themselves, thereby improving the user experience.

[0059] In this embodiment, the second switch circuit 50 includes:

[0060] a second switch tube, a third switch tube, a fifth resistor R5, a sixth resistor R6 and a first capacitor C1, wherein the input end of the second switch tube is used to connect to the power supply end, the output end of the second switch tube is electrically connected to the input end of the third switch tube and the first coil, the second coil or the third coil of the Y-shaped motor coil 60 respectively, the output end of the third switch tube is grounded, and the controlled end of the second switch tube and the controlled end of the third switch tube are both electrically connected to the main control circuit 20; the first end of the fifth resistor R5 is electrically connected to the controlled end of the second switch tube, the second end of the fifth resistor R5 is electrically connected to the output end of the second switch tube, the first end of the sixth resistor R6 is electrically connected to the controlled end of the third switch tube, and the second end of the sixth resistor R6 is electrically connected to the output end of the third switch tube; the first end of the first capacitor C1 is used to connect to the first voltage, and the second end of the first capacitor C1 is grounded.

[0061] In this embodiment, the second switch circuit 50 also includes multiple fast shutdown circuits 51. The controlled end of the second switch tube and the controlled end of the third switch tube are both electrically connected to the corresponding fast shutdown circuit 51. The fast shutdown circuit 51 is used to consume the charge remaining at the controlled end of the switch tube through a discharge circuit when the switch tube is disconnected, so that the switch tube can be quickly turned off to improve the control accuracy and stability of the motor. The fast shutdown circuit 51 is a circuit composed of a diode and at least one resistor.

[0062] refer to Figure 3 , the plurality of second switch tubes include NMOS tube Q1, NMOS tube Q3 and NMOS tube Q5 respectively, the plurality of third switch tubes include NMOS tube Q2, NMOS tube Q4 and NMOS tube Q6 respectively, the common end between NMOS tube Q1 and NMOS tube Q2 is electrically connected to the first coil U of the Y-type motor coil 60, the common end between NMOS tube Q3 and NMOS tube Q4 is electrically connected to the second coil W of the Y-type motor coil 60, and the common end between NMOS tube Q5 and NMOS tube Q6 is electrically connected to the third coil V of the Y-type motor coil 60; the main control circuit 20 controls one of the second switch tubes to be turned on and one of the third switch tubes, and the other second switch tubes and the third switch tubes are turned off, so that the current at the power supply end flows to the Y-type motor coil 60 through one of the coils, and then flows out of the Y-type motor coil 60 into another coil, so that a magnetic field change is generated between each coil, thereby effectively converting the electric energy at the power supply end into mechanical energy to drive the motor to rotate. For example, when the NMOS tubes Q1 and Q4 are turned on and the other NMOS tubes are turned off, the current at the power supply end flows to the first coil U through the NMOS tube Q1 and flows out from the third coil V through the NMOS tube Q4. When the first coil U and the third coil V are energized, a magnetic field change is generated, thereby driving the motor to rotate.

[0063] refer to Figure 4 In one embodiment of the utility model, the motor moisture-proof circuit further includes:

[0064] A zero-crossing detection circuit 70 and a rectifier bridge circuit 80, wherein the first end of the rectifier bridge circuit 80 is used to access the live wire, the second end of the rectifier bridge circuit 80 is electrically connected to the power supply end, the third end of the rectifier bridge circuit 80 is used to access the neutral wire, and the fourth end of the rectifier bridge circuit 80 is grounded; the detection end of the zero-crossing detection circuit 70 is electrically connected to the first end of the rectifier bridge circuit 80, the output end of the zero-crossing detection circuit 70 is electrically connected to the main control circuit 20, and the zero-crossing detection circuit 70 is used to detect the voltage of the first end of the rectifier bridge circuit 80 and output a corresponding zero-crossing detection signal to the main control circuit 20.

[0065] In this embodiment, the rectifier bridge circuit 80 is used to rectify the mains power and output direct current to the power supply end. The detection end of the zero-crossing detection circuit 70 is electrically connected to the first end of the rectifier bridge circuit 80 to detect the zero point between the positive half cycle and the negative half cycle of the alternating current. Each time a zero-point zero-crossing detection circuit 70 is detected, the zero-crossing detection circuit 70 will output a zero-crossing detection signal to the main control circuit 20. If the main control circuit 20 does not receive the zero-crossing detection signal within a preset time, the electrical connection between the alternating current and the rectifier bridge circuit 80 is disconnected. With such a configuration, in actual application, the user plugs the plug of the fan into the socket to connect to the mains power to power the fan. When the plug of the fan fails and causes a leakage accident in the fan, there is no zero point of the alternating current at the input end of the rectifier bridge circuit 80. At this time, the zero-crossing detection circuit 70 cannot output the zero-crossing detection signal. After the main control circuit 20 does not receive the zero-crossing detection signal within the preset time, it controls the electrical connection between the mains power and the rectifier bridge circuit 80 to be disconnected, for example, the switch tube such as a relay or a gate between the mains power and the rectifier bridge circuit 80 is disconnected, thereby protecting the safety of the hair dryer and the user.

[0066] In this embodiment, the zero-crossing detection circuit 70 includes:

[0067] A second photocoupler D2, a seventh resistor R7, an eighth resistor R8 and a second capacitor C2, the second photocoupler D2 includes a second phototransistor and a second photodiode, the input end of the second phototransistor is electrically connected to the second end of the seventh resistor R7, the first end of the seventh resistor R7 is electrically connected to the first end of the rectifier bridge circuit 80, and the output end of the second phototransistor is electrically connected to the third end of the rectifier bridge circuit 80; the input end of the second photodiode is electrically connected to the second end of the eighth resistor R8, the second end of the eighth resistor R8 is electrically connected to the first end of the second capacitor C2, the first end of the second capacitor C2 is electrically connected to the main control circuit 20, the first end of the eighth resistor R8 is used to access the first voltage, the output end of the second photodiode and the second end of the second capacitor C2 are both grounded; wherein the zero-crossing detection signal includes the first voltage.

[0068] In this embodiment, when the alternating current is at the zero point between the positive half cycle and the negative half cycle, the voltage at the input end of the rectifier bridge circuit 80 is zero, the second photodiode is cut off, and the second phototransistor is also cut off. At this time, the main control circuit 20 detects the first voltage; when the alternating current is in the positive half cycle or the negative half cycle, the second photodiode is turned on, and the second phototransistor is also turned on. The first voltage flows to the ground through the second phototransistor. At this time, the voltage detected by the main control circuit 20 is zero. If the main control circuit 20 does not receive the zero-crossing detection signal, that is, the first voltage, within the preset time, the electrical connection between the alternating current and the rectifier bridge circuit 80 is disconnected to protect the safety of the fan and the user in time; the second capacitor C2 can filter the zero-crossing detection signal to eliminate the noise and interference of the zero-crossing detection signal, thereby improving the detection accuracy of the main control circuit 20.

[0069] The utility model also provides a fan, comprising any one of the above-mentioned motor moisture-proof circuits.

[0070] It is worth noting that since the fan of the utility model is based on the above-mentioned motor moisture-proof circuit, the embodiments of the fan of the utility model include all technical solutions of all embodiments of the above-mentioned motor moisture-proof circuit, and the technical effects achieved are also exactly the same, which will not be repeated here.

[0071] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A motor moisture-proof circuit, used in fans, It is characterized in that include: A temperature and humidity detection circuit, which is used to detect the temperature and humidity of the environment and output a corresponding detection signal; A main control circuit, the main control circuit is electrically connected to the output end of the temperature and humidity detection circuit to receive the detection signal; Heating circuit; a first switch circuit, wherein an input end of the first switch circuit is electrically connected to a power supply end, an output end of the first switch circuit is electrically connected to a power supply end of the heating circuit, and a controlled end of the first switch circuit is electrically connected to the main control circuit; The main control circuit is used to control the operation of the first switch circuit according to the detection signal, so that the power supply end outputs a corresponding current to the heating circuit through the first switch circuit.

2. A motor moisture-proof circuit as claimed in claim 1, It is characterized in that The first switch circuit comprises: A first switch tube, a first photocoupler, a first resistor, a second resistor, a third resistor and a fourth resistor, wherein the first photocoupler includes a first phototransistor and a first photodiode, the input end of the first switch tube is electrically connected to the power supply end, the output end of the first switch tube is electrically connected to the heating circuit and the first end of the first resistor respectively, the controlled end of the first switch tube is electrically connected to the output end of the first phototransistor, the second end of the first resistor is electrically connected to the first end of the second resistor, the second end of the second resistor is electrically connected to the input end of the first phototransistor, the input end of the first photodiode and the first end of the third resistor are both used to access a first voltage, the output end of the first photodiode is electrically connected to the second end of the third resistor and the first end of the fourth resistor respectively, and the second end of the fourth resistor is electrically connected to the main control circuit.

3. A motor moisture-proof circuit as claimed in claim 1, It is characterized in that The heating circuit includes at least one heating wire, and the at least one heating wire is electrically connected to the output end of the first switch circuit.

4. A motor moisture-proof circuit as claimed in claim 1, It is characterized in that The motor moisture-proof circuit also includes: A second switch circuit and a motor coil, wherein the input end of the second switch circuit is used to access the power supply end, and the output end of the second switch circuit is electrically connected to the motor coil; the controlled end of the second switch circuit is electrically connected to the main control circuit, and the main control circuit is used to control the operation of the second switch circuit according to the detection signal, so that the power supply end outputs a corresponding current to the motor coil through the first switch circuit.

5. A motor moisture-proof circuit as claimed in claim 4, It is characterized in that The motor moisture-proof circuit includes multiple second switching circuits, the motor coil includes a Y-type motor coil, the Y-type motor coil includes a first coil, a second coil and a third coil, and the output ends of the multiple second switching circuits are electrically connected to the first coil of the Y-type motor coil, the second coil of the Y-type motor coil and the third coil of the Y-type motor coil, respectively.

6. A motor moisture-proof circuit as claimed in claim 5, It is characterized in that The second switch circuit comprises: A second switch tube, a third switch tube, a fifth resistor, a sixth resistor and a first capacitor, wherein the input end of the second switch tube is used to connect to the power supply end, the output end of the second switch tube is electrically connected to the input end of the third switch tube and the first coil, the second coil or the third coil of the Y-shaped motor coil respectively, the output end of the third switch tube is grounded, and the controlled end of the second switch tube and the controlled end of the third switch tube are both electrically connected to the main control circuit; the first end of the fifth resistor is electrically connected to the controlled end of the second switch tube, the second end of the fifth resistor is electrically connected to the output end of the second switch tube, the first end of the sixth resistor is electrically connected to the controlled end of the third switch tube, and the second end of the sixth resistor is electrically connected to the output end of the third switch tube; the first end of the first capacitor is used to connect to the power supply end, and the second end of the first capacitor is grounded.

7. The motor moisture-proof circuit according to claim 1, It is characterized in that The motor moisture-proof circuit also includes: A zero-crossing detection circuit and a rectifier bridge circuit, wherein the first end of the rectifier bridge circuit is used to access the live wire, the second end of the rectifier bridge circuit is electrically connected to the power supply end, the third end of the rectifier bridge circuit is used to access the neutral wire, and the fourth end of the rectifier bridge circuit is grounded; the detection end of the zero-crossing detection circuit is electrically connected to the first end of the rectifier bridge circuit, the output end of the zero-crossing detection circuit is electrically connected to the main control circuit, and the zero-crossing detection circuit is used to detect the voltage of the first end of the rectifier bridge circuit and output a corresponding zero-crossing detection signal to the main control circuit.

8. The motor moisture-proof circuit according to claim 7, It is characterized in that The zero-crossing detection circuit comprises: A second photocoupler, a seventh resistor, an eighth resistor and a second capacitor, the second photocoupler includes a second phototransistor and a second photodiode, the input end of the second phototransistor is electrically connected to the second end of the seventh resistor, the first end of the seventh resistor is electrically connected to the first end of the rectifier bridge circuit, and the output end of the second phototransistor is electrically connected to the third end of the rectifier bridge circuit; the input ends of the second photodiode are respectively electrically connected to the second end of the eighth resistor, the second end of the eighth resistor is electrically connected to the first end of the second capacitor, the first end of the second capacitor is electrically connected to the main control circuit, the first end of the eighth resistor is used to access the first voltage, and the output end of the second photodiode and the second end of the second capacitor are both grounded; wherein the zero-crossing detection signal includes the first voltage.

9. A fan, It is characterized in that The invention comprises a motor moisture-proof circuit as described in any one of claims 1 to 8.

Images