Multi-air-duct blower driven by multiple motors alternately and control method of multi-air-duct blower

Abstract

The invention discloses a multi-air-duct blower driven by multiple motors alternately and a control method of the multi-air-duct blower, and relates to the technical field of personal care electric appliances. The U-shaped shell is of a U-shaped structure, at least two sets of air outlets are formed in the inner side of the shell and used for supplying air around the head of a user during use, and a left air inlet and a right air inlet are formed in the bottoms of the two ends of the shell respectively; the at least two groups of air duct systems are arranged in the U-shaped shell, and each group of air duct system comprises a motor and a heating body; the control unit is arranged in the U-shaped shell, electrically connected with the air duct systems and used for controlling the air duct systems to work alternately. On the premise that safe compatibility of the household socket is guaranteed, equivalent high-power quick hair drying, surrounding type comfortable air supply, intelligent self-adaptive adjustment and multiple safety protection are achieved, and the technical problems that due to power superposition of an existing double-air-duct blower, the socket is overloaded, and a traditional blower is locally overheated are solved.

Description

Technical Field

[0001] This invention belongs to the field of personal care electrical appliance technology, specifically a multi-channel hair dryer driven by multiple motors and its control method. Background Technology

[0002] To meet consumers' demand for "quick hair drying," current household hair dryers have seen continuous increases in power, with mainstream products currently ranging from 1800W to 2200W. However, pursuing even higher power (such as 3000W and above) encounters a practical bottleneck: the 10A sockets widely used in ordinary households and hotels have a maximum power capacity of 2200W (220V×10A). Forcing a high-power hair dryer into the socket can easily lead to overheating of the socket, tripping of the circuit breaker, and even fire.

[0003] To address the airflow issue, dual-channel hair dryers have emerged on the market. For example, Chinese patent CN117179432A discloses a dual-channel hair dryer. However, its design involves both channels operating simultaneously. While this increases airflow, it doesn't resolve the conflict between high power and socket compatibility. In fact, the combined power increases the requirements for the socket. Furthermore, traditional single-point airflow hair dryers can easily cause overheating of the scalp when blowing on the same area for extended periods, resulting in a poor user experience.

[0004] Therefore, we propose a multi-channel blower with alternating multi-motor drive and its control method to solve the problems mentioned above.

[0005] The information disclosed above in this background section is only for enhancing the understanding of the background technology of this invention, and therefore may include prior art that is not known to those skilled in the art. Summary of the Invention

[0006] The present invention aims to provide a hair dryer and its control method that can achieve high-power and fast hair drying, be safely compatible with ordinary household 10A sockets, and provide a comfortable surround-style hair drying experience.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a multi-channel blower driven by alternating multiple motors, comprising:

[0008] The U-shaped shell has a U-shaped structure and at least two sets of air outlets on the inside of the shell, which are used to deliver air around the user's head during use. The bottom of the two ends of the shell are the left air inlet and the right air inlet, respectively.

[0009] At least two sets of air duct systems are installed inside the U-shaped housing, and each set of air duct systems includes a motor and a heating element;

[0010] The control unit, located inside the U-shaped housing, is electrically connected to each group of air duct systems and is used to control the alternating operation of each group of air duct systems;

[0011] The control unit is configured to activate only one set of air duct systems at any given time, and to make each set of air duct systems work alternately at a switching frequency of 20Hz to 50Hz. The nominal total power of the whole machine is greater than 2200W, and the instantaneous input power at any given time does not exceed 2200W.

[0012] Preferably, the air outlet includes a left air outlet and a right air outlet respectively disposed on both sides of the U-shaped housing, and the air duct system includes a first air duct system disposed inside the left end of the U-shaped housing and a second air duct system disposed inside the right end of the U-shaped housing. The first air duct system includes a first motor and a first heating element, and the second air duct system includes a second motor and a second heating element.

[0013] Preferably, the control unit includes:

[0014] The main control MCU is used to generate pulse width modulation signals;

[0015] Zero-crossing detection circuit, connected to MCU, is used to detect the zero-crossing point of AC current;

[0016] The first and second thyristor drive circuits are respectively connected to the MCU and are alternately turned on under the control of the MCU;

[0017] The first bidirectional thyristor and the second bidirectional thyristor are respectively connected between the first air duct system and the AC power supply, and between the second air duct system and the AC power supply, and are controlled by the corresponding thyristor drive circuits.

[0018] Preferably, a distance sensor is also provided at the air outlet of the U-shaped housing. The distance sensor is electrically connected to the control unit and is used to detect the distance between the air outlet and the hair. The control unit adjusts the switching frequency in real time according to the distance.

[0019] Preferably, the control unit is configured as follows:

[0020] When the distance is less than the first threshold, the switching frequency is increased to 40Hz to 50Hz;

[0021] When the distance is greater than the second threshold, the switching frequency is reduced to 20Hz to 30Hz.

[0022] Preferably, the first threshold is 10cm and the second threshold is 20cm.

[0023] Preferably, a temperature sensor is also provided at the air outlet of the U-shaped housing to monitor the air outlet temperature in real time and feed it back to the control unit; when the air outlet temperature exceeds the safety threshold, the control unit reduces the power or duty cycle of the corresponding heating element.

[0024] A control method for a multi-motor alternating-drive multi-duct hair dryer, applied to the aforementioned hair dryer, includes the following steps:

[0025] At any given time, the control unit can only activate any one set of air duct systems, enabling it to operate at a power of 2200W.

[0026] Multiple duct systems switch at a high frequency of 20Hz to 50Hz, and the working time of each duct system is equal within a complete switching cycle.

[0027] The unit has a nominal total power of 4400W, but the instantaneous input power at any given time is ≤2200W, and it is compatible with ordinary household 10A sockets.

[0028] Preferred options also include:

[0029] The distance between the air vent and the hair is detected by a distance sensor;

[0030] When the detected distance is less than the first threshold, the switching frequency is increased to 40Hz to 50Hz;

[0031] When the distance is detected to be greater than the second threshold, the switching frequency is reduced to 20Hz to 30Hz.

[0032] Preferred options also include:

[0033] The outlet air temperature is monitored in real time using a temperature sensor;

[0034] When the outlet air temperature exceeds the safety threshold, the power or duty cycle of the corresponding heating element is reduced.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] 1. The control unit of this invention enables two sets of motors to work alternately at a frequency of 20Hz to 50Hz, with only one set activated at any given time. The instantaneous input power does not exceed 2200W, and it can be safely connected to a standard household 10A socket. The total rated power of the entire machine is 4400W, which significantly improves the drying efficiency and breaks through the bottleneck of traditional hair dryers being limited by the socket's load-bearing capacity. With a U-shaped shell and air outlets on both sides, air is delivered around the user's head during use. Combined with the high-frequency alternating airflow method, it avoids the problem of overheating of the scalp caused by traditional single-point airflow blowing on the same area for a long time, making the hair drying process more even and comfortable.

[0037] 2. This invention uses a distance sensor to detect the distance between the air outlet and the hair in real time. The control unit dynamically adjusts the switching frequency according to the distance: when the distance is close, the frequency is increased to reduce the continuous airflow time on one side and prevent local overheating and burns; when the distance is far, the frequency is reduced to maintain a balanced circumferential airflow, thus achieving intelligent safety protection and comfort optimization.

[0038] 3. This invention installs a temperature sensor at the air outlet to monitor the air outlet temperature in real time and feeds it back to the control unit. When the temperature exceeds the safety threshold, it automatically reduces the power or duty cycle of the corresponding heating element, effectively preventing high temperature damage to hair and scalp and improving the overall safety of the device.

[0039] 4. The control unit of the present invention can flexibly adjust the duty cycle of the two sets of air duct systems within a switching cycle to achieve different lateral air volume and heat distribution, adapting to various usage scenarios such as rapid dehumidification in the early stage of hair drying, balanced styling in the middle and late stages, and hair end care, thus expanding the functional applicability of the product.

[0040] 5. In summary, this invention achieves equivalent high-power rapid hair drying, surround-style comfortable airflow, intelligent adaptive adjustment, and multiple safety protections while ensuring the safety and compatibility of household sockets. It overcomes the technical problems of socket overload caused by the superposition of power in existing dual-channel hair dryers and local overheating in traditional hair dryers. Attached Figure Description

[0041] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0042] Figure 1 : A three-dimensional structural diagram of the U-shaped multi-motor alternating drive multi-channel blower of the present invention.

[0043] Figure 2 : Internal structural layout diagram of the U-shaped shell of this invention.

[0044] Figure 3 : Block diagram of the control circuit of this invention.

[0045] Figure 4 The timing diagram of this invention has a period of 33.3ms and a duty cycle of 50%.

[0046] In the picture:

[0047] 1. U-shaped housing; 101. Left air outlet; 102. Right air outlet; 103. Left air inlet; 104. Right air inlet; 2. First air duct system; 201. First motor; 202. First heating element; 3. Second air duct system; 301. Second motor; 302. Second heating element; 4. Control unit; 5. Zero-crossing detection circuit; 6. First thyristor; 7. Second thyristor; 8. First temperature sensor; 10. Distance sensor. Detailed Implementation

[0048] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0049] Example 1: Multi-channel hair dryer driven by alternating motors

[0050] Please see Figure 1-3 A multi-motor alternating drive multi-duct blower includes a U-shaped housing 1, a first duct system 2, a second duct system 3, a control unit 4, a zero-crossing detection circuit 5, a first thyristor 6, a second thyristor 7, a temperature sensor 8, and a distance sensor 10.

[0051] The U-shaped housing 1 has a U-shaped structure with a left air outlet 101 and a right air outlet 102 at its two ends, respectively, for delivering air around the user's head during use. The bottom of each end of the housing has a left air inlet 103 and a right air inlet 104, respectively. The U-shaped housing 1 is supported by an adjustable-height bracket, making it convenient for the user to stand or sit under the U-shaped housing 1.

[0052] The first air duct system 2 is located inside the left end of the U-shaped housing 1, and includes a first motor 201 and a first heating element 202. The first motor 201 is a 200W brushless motor, and the first heating element 202 is a 2000W nickel-chromium heating wire assembly. Both are located inside the left end of the U-shaped housing 1, and guide vanes are provided at the air outlet.

[0053] The second air duct system 3 has the same structure as the first air duct system 2, and is located inside the right end of the U-shaped housing 1. It includes a second motor 301 and a second heating element 302. Both the first motor 201 and the second motor 301 are high-speed brushless motors with a power of 200W, and both the first heating element 202 and the second heating element 302 have a power of 2000W. The nominal total power of the whole machine is 4400W.

[0054] The control unit 4 is located inside the U-shaped housing 1 and is electrically connected to the first air duct system 2 and the second air duct system 3 respectively.

[0055] In this embodiment, the control unit 4 is located in the middle of the U-shaped housing 1, and includes a main control MCU chip and peripheral circuits. The MCU chip is Peak Power FU6812L or a similar motor drive dedicated chip.

[0056] The zero-crossing detection circuit 5 is located inside the control unit 4 and is electrically connected to the control unit 4. It is used to detect the zero-crossing point of the AC current.

[0057] In this embodiment, the first thyristor 6 (model JST139E-800E) is connected between the first air duct system 2 and the AC power supply, and its control terminal is connected to the MCU after optocoupler isolation. The second thyristor 7 is connected in the same way as the first thyristor 6. Both the first thyristor 6 and the second thyristor 7 are 16A / 800V bidirectional thyristors. Overcurrent protection components are also connected between the first thyristor 6 and the first air duct system 2, and between the second thyristor 7 and the second air duct system 3.

[0058] Temperature sensors 8 are located at the two air outlets and are electrically connected to the control unit 4. All temperature sensors 8 are NTC thermistors.

[0059] Distance sensors 10 are respectively installed at the two air outlets and electrically connected to the control unit 4 to detect the distance between the air outlets and the hair. In this embodiment, the distance sensors 10 are infrared distance sensors or ultrasonic distance sensors, model GP2Y0A21YK0F, and are embedded near the left air outlet 101 and the right air outlet 102.

[0060] It also includes a power cord (not shown in the figure), which is connected to the control unit 4 and is equipped with a national standard 10A plug at its end.

[0061] In addition, this device is equipped with a button panel for displaying the operating status and receiving user input and output. Users can set the operating mode, such as cold air mode, hot air mode, alternating cycle adjustment, and temperature settings via the button panel. The button panel also features an LED display or indicator lights to show the current operating status, set temperature, fan speed, and other information in real time, enhancing the interactive experience.

[0062] Example 2: Basic Alternating Control Mode

[0063] This embodiment provides a basic working mode for a multi-motor alternating drive multi-channel hair dryer, aiming to achieve a unified high-power output of the whole machine and compatibility with ordinary household sockets.

[0064] Specifically, the control unit 4 includes a main control MCU, a zero-crossing detection circuit 5, a first thyristor drive circuit, a second thyristor drive circuit, a first bidirectional thyristor 6, and a second bidirectional thyristor 7. The main control MCU uses the PeakTech FU6812L dedicated motor driver chip, which integrates a PWM generation module and a timer to output precise alternating conduction control signals.

[0065] In this embodiment, the MCU is configured to control the two sets of air duct systems to work alternately at a fixed switching frequency of 30Hz, with a single switching cycle of approximately 33.3ms. The zero-crossing detection circuit 5 detects the zero-crossing point of the AC power supply in real time and inputs a synchronization signal to the MCU. After each zero-crossing point, the MCU outputs high / low level signals through the I / O port according to a preset timing sequence. These signals, after optocoupler isolation, trigger the first bidirectional thyristor 6 and the second bidirectional thyristor 7, model JST139E-800E, respectively.

[0066] Within a complete switching cycle, for the first 16.65ms, the first bidirectional thyristor 6 is turned on, the first air duct system 2 is connected to AC power, the first motor 201 and the first heating element 202 operate at a nominal power of 2200W, and air is discharged from the left air outlet 101; for the next 16.65ms, the first bidirectional thyristor 6 is turned off, the second bidirectional thyristor 7 is turned on, the second air duct system 3 operates at a power of 2200W, and air is discharged from the right air outlet 102. This cycle repeats continuously. The nominal total power of the entire unit is 4400W, but the instantaneous input power at any given time does not exceed 2200W, and it can be safely connected to a standard household 10A socket. Figure 4 The voltage / current timing waveforms of the left and right motors working alternately in this embodiment are shown.

[0067] Example 3: Distance Adaptive Intelligent Control Mode

[0068] Based on Example 1, this embodiment further introduces a distance adaptive control mechanism to optimize the safety and comfort of use at different blow-drying distances.

[0069] A distance sensor 10 is installed at the air outlet of the U-shaped housing 1. Specifically, it is an infrared distance sensor, model GP2Y0A21YK0F, with a detection range of 10cm to 80cm. This sensor is electrically connected to the MCU in the control unit 4. The MCU reads the analog voltage value output by the sensor in real time and converts it into a distance value through its internal ADC.

[0070] The MCU has preset distance thresholds: a first threshold of 10cm and a second threshold of 20cm. When the distance between the air outlet and the hair is detected to be less than 10cm, the MCU determines it to be a close-range hair drying state. At this time, it automatically increases the switching frequency of the air duct system from the default 30Hz to 50Hz, and shortens the cycle to 20ms. The higher switching frequency reduces the continuous airflow time of a single air duct from 16.65ms to 10ms, effectively preventing the risk of localized scalp overheating or high-temperature burns caused by prolonged fixed-point blowing.

[0071] When the detected distance exceeds 20cm, the MCU determines it to be in a long-distance hair-drying state and automatically reduces the switching frequency to 30Hz to maintain a balanced surround airflow experience. If the distance further exceeds 30cm, the MCU determines it to be in standby or off-head state. In this case, it can control the two sets of air duct systems to work intermittently or only maintain the motor running at a low speed to output a gentle breeze to reduce power consumption and ensure safe use.

[0072] Example 4: Asymmetric Power Allocation Mode

[0073] This embodiment provides an asymmetric duty cycle control method to adapt to the different needs of air volume and heat distribution for different hairstyles and different drying stages.

[0074] In this embodiment, the MCU is equipped with an adjustable duty cycle control register. The user can send the duty cycle setting value to the MCU via the mode selection button on the blower or through a wireless connection with an external mobile terminal APP. The MCU dynamically adjusts the working time ratio of the two sets of air duct systems within a complete switching cycle, ensuring that only one set of air duct systems is activated at any given time.

[0075] Specifically, in the initial stage of drying hair, to quickly remove moisture from the hair roots and large areas of wet hair, the duty cycle can be set to 60%:40%, meaning that the first air duct system 2 works for 60% of the time in one cycle, and the second air duct system 3 works for 40% of the time, forming a strong directional airflow. In the middle and later stages of drying hair, or for thinner hair, the duty cycle can be set to 50%:50% to achieve balanced, circular airflow. During the hair end conditioning or cool air styling stage, the duty cycle can be set to 30%:70%, changing the main airflow side to adapt to different lateral drying needs.

[0076] Regardless of the duty cycle configuration, the MCU synchronizes the AC power phase through the zero-crossing detection circuit 5, ensuring that each air duct system operates near the zero-crossing point during both turn-on and turn-off, thereby reducing the switching losses of the thyristors and electromagnetic interference. The instantaneous input power of the entire unit never exceeds 2200W, is compatible with ordinary household 10A sockets, and simultaneously achieves flexible distribution of equivalent total power and a personalized hair drying experience.

[0077] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0078] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0079] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A multi-motor alternating-drive multi-duct hair dryer, characterized in that, include: The U-shaped housing (1) has a U-shaped structure and at least two sets of air outlets are provided on the inner side of the housing for blowing air around the user's head during use. The bottom of the two ends of the housing are the left air inlet (103) and the right air inlet (104). At least two sets of air duct systems are installed inside the U-shaped housing, and each set of air duct systems includes a motor and a heating element; The control unit (4) is located inside the U-shaped housing (1) and is electrically connected to each group of air duct systems to control the alternating operation of each group of air duct systems. The control unit (4) is configured to activate only one set of air duct systems at any given time, and to make each set of air duct systems work alternately at a switching frequency of 20Hz to 50Hz. The total nominal power of the whole machine is greater than 2200W, and the instantaneous input power at any given time does not exceed 2200W.

2. The multi-motor alternating drive multi-duct hair dryer according to claim 1, characterized in that: The air outlet includes a left air outlet (101) and a right air outlet (102) respectively located on both sides of the U-shaped housing (1). The air duct system includes a first air duct system (2) located inside the left end of the U-shaped housing (1) and a second air duct system (3) located inside the right end of the U-shaped housing (1). The first air duct system (2) includes a first motor (201) and a first heating element (202). The second air duct system (3) includes a second motor (301) and a second heating element (302).

3. A multi-motor alternating drive multi-duct blower according to claim 1, characterized in that: The control unit (4) includes: The main control MCU is used to generate pulse width modulation signals; Zero-crossing detection circuit (5) is connected to the MCU and is used to detect the zero-crossing point of AC power. The first and second thyristor drive circuits are respectively connected to the MCU and are alternately turned on under the control of the MCU; The first bidirectional thyristor (6) and the second bidirectional thyristor (7) are respectively connected between the first air duct system (2) and the AC power supply, and between the second air duct system (3) and the AC power supply, and are controlled by the corresponding thyristor drive circuit.

4. A multi-motor alternating drive multi-duct blower according to claim 1, characterized in that: A distance sensor (10) is also provided at the air outlet of the U-shaped housing (1). The distance sensor (10) is electrically connected to the control unit (4) and is used to detect the distance between the air outlet and the hair. The control unit (4) adjusts the switching frequency in real time according to the distance.

5. A multi-motor alternating drive multi-duct blower according to claim 4, characterized in that: The control unit (4) is configured to: When the distance is less than the first threshold, the switching frequency is increased to 40Hz to 50Hz; When the distance is greater than the second threshold, the switching frequency is reduced to 20Hz to 30Hz.

6. The control method for a multi-motor alternating-drive multi-duct blower according to claim 5, characterized in that: The first threshold is 10cm, and the second threshold is 20cm.

7. The control method for a multi-motor alternating-drive multi-duct blower according to claim 1, characterized in that: The U-shaped housing (1) is also equipped with a temperature sensor (8) at the air outlet, which is used to monitor the air outlet temperature in real time and feed it back to the control unit (4); when the air outlet temperature exceeds the safety threshold, the control unit (4) reduces the power or duty cycle of the corresponding heating element.

8. A control method for a multi-motor alternating-drive multi-duct hair dryer, applied to the hair dryer according to any one of claims 1 to 7, characterized in that, Includes the following steps: At any given time, the control unit (4) activates only any one set of air duct systems, enabling it to operate at a power of 2200W; Multiple duct systems switch at a high frequency of 20Hz to 50Hz, and the working time of each duct system is equal within a complete switching cycle. The unit has a nominal total power of 4400W, but the instantaneous input power at any given time is ≤2200W, and it is compatible with ordinary household 10A sockets.

9. The control method according to claim 8, characterized in that: Also includes: The distance between the air outlet and the hair is detected by the distance sensor (10); When the detected distance is less than the first threshold, the switching frequency is increased to 40Hz to 50Hz; When the distance is detected to be greater than the second threshold, the switching frequency is reduced to 20Hz to 30Hz.

10. The control method according to claim 8, characterized in that, Also includes: The outlet air temperature is monitored in real time by a temperature sensor (8); When the outlet air temperature exceeds the safety threshold, the power or duty cycle of the corresponding heating element is reduced.

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