Portable active noise reduction fan, and active noise reduction method for portable fan

Abstract

The present application discloses a portable active noise reduction fan, and an active noise reduction method for a portable fan. The portable active noise reduction fan comprises: a housing, wherein the housing is a portable housing, a cavity is formed inside the housing, and two ends of the housing are respectively provided with an air inlet and an air outlet which are in communication with each other; a fan assembly, arranged in the cavity and used for generating air pressure by means of rotation, so that air is drawn in from the air inlet, passes through the cavity, and is blown out from the air outlet; and a noise reduction assembly, arranged in the cavity and used for collecting a noise signal inside and outside the cavity in real time when the fan assembly is operating, and emitting a noise reduction signal on the basis of the noise signals, wherein the noise signal is a dynamic comprehensive noise signal comprising air inlet noise, air outlet noise, fan blade noise and / or motor noise. By reasonably designing the function of a noise reduction assembly and using a noise reduction signal to perform active noise control on noise signals, the present invention reduces the noise level of a fan during operation.

Description

Portable active noise-canceling fan and active noise-canceling method for portable fans

[0001] This application claims priority to Chinese patent applications with application numbers 202510112491.7, 202520166055.3, 202510173640.0, 202510374202.0, 202511088674.6, 202511286620.0, 202511729763.4 and 202521647414.3, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of fan technology, and in particular to a portable active noise-canceling fan and an active noise-canceling method for a portable fan. Background Technology

[0003] In recent years, people have been pursuing a more convenient life. In order to meet the needs of outdoor activities or other life scenarios, a variety of portable fan products have appeared on the market, such as handheld fans and neck fans.

[0004] In the current development of portable fans, noise is generated due to mechanical friction and airflow. The higher the fan speed and the greater the airflow, the louder the noise, resulting in a poor user experience. Current noise control methods are mostly passive, such as covering the inner walls of the fan with sound-absorbing cotton and optimizing heat dissipation channels. However, these methods have limited effectiveness in eliminating noise. Therefore, how to effectively eliminate the noise generated by the fan during operation is a technical problem that urgently needs to be solved by those skilled in the art.

[0005] Application content

[0006] The purpose of this application is to provide a portable active noise-canceling fan that can effectively reduce fan operating noise and an active noise-canceling method for portable fans.

[0007] This application provides a portable active noise-canceling fan, the portable active noise-canceling fan comprising:

[0008] The outer casing is a portable housing with a cavity inside and an air inlet and an air outlet that communicate with each other at both ends of the outer casing.

[0009] A fan assembly, disposed within the cavity, is used to rotate and generate air pressure to draw air in from the air inlet, pass through the cavity, and blow it out from the air outlet.

[0010] A noise reduction component is disposed within the cavity and is used to collect noise signals inside and outside the cavity in real time when the fan assembly is running, and to issue a noise reduction signal based on the noise signals.

[0011] The noise signal is a dynamic composite noise signal that includes intake noise, exhaust noise, fan blade noise, and / or motor noise.

[0012] This application also provides an active noise reduction method for a portable fan, the method comprising:

[0013] Acquire noise signals; the noise signals are dynamic composite noise signals generated by the portable fan during operation, including intake noise, exhaust noise, fan blade noise and / or motor noise;

[0014] The noise signal is processed by a pre-trained noise reduction model to obtain noise control instructions.

[0015] Based on the noise control command, a noise reduction signal is issued to actively control the noise of the portable fan; wherein, within a preset error allowable range, the noise reduction signal is opposite in phase and has the same frequency and amplitude as the noise signal, and is used to perform destructive interference on the noise signal. Attached Figure Description

[0016] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:

[0017] Figure 1 is a front and side perspective view of a portable active noise-canceling fan according to an exemplary embodiment;

[0018] Figure 2 is a perspective view of the back side of a portable active noise-canceling fan according to an exemplary embodiment;

[0019] Figure 3 is an exploded perspective view of a portable active noise-canceling fan according to an exemplary embodiment;

[0020] Figure 4 is a side cross-sectional view of a portable active noise-canceling fan according to an exemplary embodiment;

[0021] Figure 5 is a schematic diagram of a signal processor module according to an exemplary embodiment;

[0022] Figure 6 is a schematic diagram of a signal generator module according to an exemplary embodiment;

[0023] Figure 7 is a schematic diagram of a module of an automated signal processing system according to an exemplary embodiment;

[0024] Figure 8 is a logical schematic diagram of an automated signal processing program according to an exemplary embodiment;

[0025] Figure 9 is a logical schematic diagram of another automated signal processing procedure according to an exemplary embodiment;

[0026] Figure 10 is a schematic diagram of a signal feedback control system according to an exemplary embodiment;

[0027] Figure 11 is a schematic diagram of a memory module according to an exemplary embodiment;

[0028] Figure 12 is a schematic diagram illustrating the application of a noise reduction component according to an exemplary embodiment;

[0029] Figure 13 is a schematic diagram illustrating the application of a noise reduction model according to an exemplary embodiment;

[0030] Figure 14 is a schematic diagram illustrating an application of motor noise reduction according to an exemplary embodiment;

[0031] Figure 15 is a side cross-sectional schematic diagram of another portable active noise-canceling fan according to an exemplary embodiment;

[0032] Figure 16 is an exploded perspective view of another portable active noise-canceling fan according to an exemplary embodiment;

[0033] Figure 17 is an exploded perspective view of another portable active noise-canceling fan according to an exemplary embodiment;

[0034] Figure 18 is a side cross-sectional view of a drive motor according to an exemplary embodiment;

[0035] Figure 19 is a schematic diagram of a noise processor module according to an exemplary embodiment;

[0036] Figure 20 is a perspective view of a fan blade according to an exemplary embodiment;

[0037] Figure 21 is a perspective view of a fan blade according to an exemplary embodiment;

[0038] Figure 22 is a front view schematic diagram of a hub of a fan blade according to an exemplary embodiment;

[0039] Figure 23 is a schematic top view of the blade of a fan blade according to an exemplary embodiment;

[0040] Figure 24 is a frontal cross-sectional view of the tip of a blade according to an exemplary embodiment;

[0041] Figure 25 is an enlarged schematic diagram of point Q1 in Figure 21;

[0042] Figure 26 is a flowchart illustrating an active noise reduction method according to an exemplary embodiment;

[0043] Figure 27 is a schematic flowchart illustrating an active noise control process according to an exemplary embodiment;

[0044] Figure 28 is a schematic flowchart illustrating a process for obtaining noise control instructions according to an exemplary embodiment;

[0045] Figure 29 is a schematic diagram of another process for obtaining noise control instructions according to an exemplary embodiment;

[0046] Figure 30 is a schematic flowchart illustrating a process for extracting a noise amplitude sequence according to an exemplary embodiment;

[0047] Figure 31 is a schematic flowchart illustrating a motor noise reduction method according to an exemplary embodiment;

[0048] Figure 32 is a schematic flowchart illustrating a method for generating noise control instructions according to an exemplary embodiment;

[0049] Figure 33 is a block diagram illustrating an electronic device for active noise cancellation according to an exemplary embodiment;

[0050] Figure 34 is a block diagram illustrating a computer-readable storage medium for active noise reduction according to an exemplary embodiment;

[0051] Figure 35 is a block diagram illustrating a computer program product for active noise cancellation according to an exemplary embodiment.

[0052] The figures in the diagram are labeled as follows: 10, Portable active noise-canceling fan; 100, Outer shell; 101, Cavity; 102, Air inlet; 103, Air outlet; 104, Air inlet cover; 105, Air outlet cover; 110, Hand cover; 111, Battery module; 112, Control component; 120, Fan casing; 200, Fan assembly; 210, Motor; 211, Stator assembly; 212, Rotor assembly; 213, Circuit board; 220, Fan blade; 221, Hub; 222, Blade; 2211, Conical cavity; 2212, Annular sidewall; 2221, Blade root; 2222, Blade. Tip; 2223, Tip winglet; 2224, Leading edge winglet; 2225, Trailing edge winglet; 240, Noise reduction model; 241, Classification network; 242, Noise reduction signal database; 300, Noise reduction component; 310, Signal acquisition unit; 311, Sound sensor; 311a, First microphone; 311b, Second microphone; 311c, Third microphone; 311d, Fourth microphone; 320, Signal processor; 321, Filter; 322, Signal synthesizer; 323, Signal amplifier; 324, Analog-to-digital converter; 325, Computer chip; 326, Amplitude Comparator; 327, Decibels Comparator; 328, Error Acquisition Unit; 330, Signal Generator; 331, Sound Player; 3311, First Player; 3312, Second Player; 3313, Third Player; 331a, First Speaker; 331b, Second Speaker; 331c, Third Speaker; 331d, Fourth Speaker; 332, Power Amplifier; 340, Automated Signal Processing System; 350, Signal Feedback Control System; 400, Memory; 410, Speed-to-Noise Ratio Table; 420, Noise Reduction Signal Database; 20, Electronic Equipment; 2 1. Processor; 22. Memory; 23. Power supply assembly; 24. Network interface; 25. Input / output interface; 30. Computer-readable storage medium; 31. Computer program data; 40. Computer program product; 41. Program instructions; 50. Motor noise reduction device; 510. Noise collector; 511. First pickup; 512. Second pickup; 513. Third pickup; 520. Noise processor; 521. First processing submodule; 522. First determination submodule; 523. Second determination submodule; 524. First generation submodule; 530. Noise suppressor. Detailed Implementation

[0053] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. It is understood that the specific embodiments described herein are only for explaining this application and not for limiting it. Furthermore, it should be noted that, for ease of description, only the parts related to this application are shown in the accompanying drawings, not all structures. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0054] In this application, the reference to "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0055] The term "and / or" in the embodiments of this application refers to any and all possible combinations including one or more of the associated listed items. It should also be noted that, when used in this specification, "including / comprising" specifies the presence of the stated features, integers, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, elements, and / or components and / or groups thereof, and is intended to cover non-exclusive situations. For example, a product or device comprising a series of units is not limited to the listed units, but may optionally include units not listed, or may optionally include other units inherent to such products or devices.

[0056] The following text first describes the definitions of commonly used technical terms in this field:

[0057] 1. Active noise cancellation

[0058] Noise reduction is achieved by releasing a sound wave signal with the same or similar amplitude but opposite phase to the noise source, thereby reducing or eliminating the noise level of the noise source.

[0059] 2. Power amplifier

[0060] A power amplifier, often shortened to "amplifier," is an amplifier that can produce maximum power output to drive a load (such as a loudspeaker) under a given distortion rate. Power amplifiers play a pivotal role in the entire audio system, acting as a "coordinator" and, to a certain extent, determining whether the system can provide good sound quality.

[0061] 3. Loudspeakers

[0062] A loudspeaker, also known as a "horn," is a very common electroacoustic transducer that can be found in any electronic or electrical device that produces sound.

[0063] To explain in detail the technical content, technical steps, objectives and effects of this application, the following description is provided in conjunction with the embodiments and accompanying drawings.

[0064] With the development of technology and people's increasing demands for a comfortable living environment, noise reduction technology is being used more and more widely in electronic devices. Traditional fans generate significant noise during operation, which not only affects user comfort but may also interfere with sensitive locations (such as offices and hospitals). Therefore, developing a fan device that can effectively reduce operating noise is particularly important.

[0065] The purpose of this invention is to provide a portable active noise-canceling fan that can effectively reduce operating noise while generating cool air. This fan utilizes active noise control technology to collect noise signals in real time and generate a noise-canceling signal with opposite phase, thereby achieving noise cancellation interference and improving the user experience. Specifically:

[0066] Example 1

[0067] This invention provides a portable active noise-canceling fan 10. Referring to Figures 1 to 4, the portable active noise-canceling fan 10 includes a housing 100, a fan assembly 200, and a noise-canceling assembly 300. The housing 100 is a portable casing with a cavity 101 inside, and an air inlet 102 and an air outlet 103 communicating with each other at both ends of the housing 100. The fan assembly 200 is disposed within the cavity 101 and is used to generate wind pressure by rotating, drawing air in through the air inlet 102, passing it through the cavity 101, and then blowing it out through the air outlet 103. The noise-canceling assembly 300 is disposed within the cavity 101 and is used to collect noise signals inside and outside the cavity 101 in real time during the operation of the fan assembly 200, and to emit noise-canceling signals based on the noise signals.

[0068] Regarding the housing 100, please refer to Figures 1 and 2. The housing 100 is a user-friendly portable housing with a carefully designed structure that makes it compact and easy to carry. Inside the housing 100, there is a cavity 101 for storing the fan assembly 200 and the noise reduction assembly 300, which forms the basic frame of the noise reduction fan 10.

[0069] In some embodiments, as shown in FIG1, the shape of the noise-reducing fan 10 is mainly presented by the outer shell 100. In order to facilitate user carrying, the outer shell 100 includes a hand shell 110 for the user to hold, and a fan shell 120 for connecting the air inlet 102, the cavity 101 and the air outlet 103.

[0070] In some embodiments, as shown in Figures 3 and 4, the fan housing 120 is a hollow cylindrical structure with an internal cavity 101. An air inlet 102 communicating with the outside is provided at one end of the cavity 101, and an air outlet 103 communicating with the outside is provided at the other end. An air inlet hood 104 is provided on one side of the air inlet 102, and an air outlet hood 105 is provided on one side of the air outlet 103. Air can be drawn into the cavity 101 through the air inlet hood 102 via the air inlet hood 104, and then discharged through the air outlet hood 105 via the air outlet 103, thereby improving the overall airflow efficiency of the device. Simultaneously, the miniature design of the cavity 101 ensures the flexibility of the device during use.

[0071] In some embodiments, the air inlet 102 and the air outlet 103 are respectively located at the two ends of the air casing 120. The cross-sectional shape of the air inlet 102 and the air outlet 103 is circular, and the axes of the air inlet 102, the air outlet 103 and the cavity 101 are the same straight line.

[0072] In this embodiment, the cross-sections of the cavity 101, air inlet 102, and air outlet 103 are circular to ensure uniform suction and consistent external dimensions without differences in angle of use. Additionally, it maintains a consistent wall thickness for the fan housing 120, thereby guaranteeing the overall strength of the fan housing 120. In some embodiments, the cross-sectional shape of the cavity 101 can be elliptical or polygonal, and the cross-sections of the air inlet 102 and air outlet 103 can be oblong or rectangular polygonal. Furthermore, the positions of the air inlet 102 and air outlet 103 can be offset from the axis of the cavity 101. This application does not impose specific limitations on these aspects.

[0073] In this embodiment, the axis of the fan housing 120 is the central axis of the cylindrical shape. The airflow direction of the fan assembly 200 for the noise-reducing fan 10 during operation is parallel to this axis. In other embodiments, when the fan housing 120 is not cylindrical, its axis extends from the main structure, and the airflow direction is parallel to this axis. A buffer sleeve (not labeled, hereinafter the same) is also wrapped around the outside of the fan housing 120. Of course, in other embodiments, the buffer sleeve may not be provided.

[0074] In some embodiments, a battery module 111 and a control component 112 are provided inside the hand housing 110, and a fan assembly 200 and a noise reduction component 300 are provided inside the fan housing 120. The battery module 111 (e.g., a battery) that powers various components within the hand housing 110 of the noise reduction fan 10 can be logically connected to the noise reduction component 300 through a power management system, thereby enabling functions such as charging, discharging, and power consumption management through the power management system.

[0075] As shown in Figures 1 and 2, in one embodiment, the length of the hand shell 110 is 52-62mm, the width of the hand shell 110 is 25.5-35.5mm, the height of the hand shell 110 is 96.6-106.6mm, and the overall volume of the hand shell 110 is relatively small, so that the hand shell 110 is convenient for the user to hold.

[0076] The fan assembly 200 includes a motor 210 and a fan blade 220. The control assembly 112 controls the battery module 111 to supply power to the motor 210. The motor 210 drives the fan blade 220 to rotate to generate wind pressure, thereby drawing air in from the air inlet 102, passing through the cavity 101, and blowing it out from the air outlet 103.

[0077] In some embodiments, the fan blade 220 is housed within the cavity 101 and disposed on the side near the air inlet 102. The motor 210 includes a stator assembly 211 and a rotor assembly 212. The outer diameter of the motor 210 is smaller than the inner diameter of the cavity 101, and the motor 210 is mounted inside the cavity 101.

[0078] In some embodiments, the fan blade 220 includes a hub 221 and a plurality of blades 222 spaced around the hub 221. The outer diameter of the motor 210 is smaller than the maximum inner diameter of the hub 221, so a portion of the motor 210 can also be housed inside the hub 221. In this embodiment, the hub 221 increases radially from back to front, while the fan casing 120 remains constant radially from back to front. The maximum diameter of the hub 221 is not greater than the diameter of the fan casing 120, allowing the airflow generated by the rotation of the fan blade 220 to flow smoothly to the outside of the fan casing 120, reducing wind resistance and wind loss. In other embodiments, the difference between the maximum diameter of the hub 221 and the diameter of the fan casing 120 is less than 2 mm, which also achieves the effect of reducing wind resistance and wind loss.

[0079] As shown in Figures 3 and 4, in one embodiment, the rotor assembly 212 includes a shaft, a bearing, a magnetic ring, and a yoke. The bearing is housed within a bearing housing, and one end of the shaft is fixed to the bearing housing via the bearing. The magnetic ring is fixed radially inner to the yoke, and the yoke is fixedly connected to the shaft. The yoke and magnetic ring are located radially outer to the bearing housing. The stator assembly 211 is located between the bearing housing and the magnetic ring, and the other end of the shaft is fixedly connected to the fan blade 220. That is, the magnetic ring is located radially outer to the stator assembly 211, and the motor 210 is an external rotor motor. Furthermore, since the magnetic ring is fixed radially inner to the yoke, and the yoke is fixedly connected to the shaft, when the stator assembly 211 drives the magnetic ring to rotate, the magnetic ring simultaneously drives the yoke, and the yoke drives the shaft to rotate. Therefore, the magnetic ring or yoke does not need to be connected to the motor 210; the motor 210 can be fixedly connected to the other end of the shaft, and the shaft drives the motor 210 to rotate.

[0080] As shown in Figures 3 and 4, in one embodiment, the bearing includes a first bearing located at the front, a second bearing located at the rear, and a buffer member disposed between the first and second bearings. The second bearing is directly abutted at the front end of the inner wall of the cavity 101, or an elastic member is provided between the front end of the inner wall and the second bearing. The buffer member can be a single spring, or it can consist of a spring and a rubber sleeve, or it can be made of other elastic materials. The elastic member can be a spring or other elastic materials.

[0081] In some embodiments, the portable active noise-canceling fan 10 is applied to a high-speed motor that operates at a speed exceeding a preset speed; wherein the high-speed motor includes a high-speed three-phase motor.

[0082] Specifically, the portable active noise-canceling fan 10 can be used with a high-speed motor operating at speeds exceeding a preset speed (e.g., above 12,000 rpm). Such high-speed motors tend to generate high noise during actual operation, thus requiring active noise reduction control via the portable active noise-canceling fan 10. In some preferred embodiments, the high-speed motor can be a high-speed three-phase motor, which can provide sufficient power and speed to ensure adequate airflow from the portable active noise-canceling fan 10. Furthermore, to ensure good overall vibration damping while using a high-speed three-phase motor, a buffer can be installed on the inner wall of the housing 100. This buffer can absorb and reduce vibrations from the high-speed three-phase motor, allowing the portable active noise-canceling fan 10 to rotate continuously and stably at high speed.

[0083] As shown in Figures 3 and 4, in one embodiment, the motor 210 is a three-phase high-speed motor, and the motor 210 also includes a drive plate. A fixing hole is provided inside the fan housing 120, and the drive plate is provided with a fixing opening. A fixing member passes through the fixing opening and is fixed to the fixing hole, thereby fixing the drive plate to the fan housing 120.

[0084] The noise reduction component 300 includes a signal acquisition unit 310, a signal processor 320, and a signal generator 330. The signal acquisition unit 310 is disposed within the cavity 101 and is used to acquire noise signals in real time during the operation of the fan assembly 200. The signal processor 320 is disposed within the cavity 101 and electrically connected to the signal acquisition unit 310, and is used to acquire noise signals and generate signal generation commands based on the noise signals. The signal generator 330 is disposed within the cavity 101 and electrically connected to the signal processor 320, and is used to acquire signal generation commands and emit noise reduction signals based on the signal generation commands.

[0085] In some embodiments, the noise signal collected by the signal acquisition unit 310 is a dynamic comprehensive noise signal including air intake noise, air exhaust noise, fan blade noise and / or motor noise; wherein, air intake noise and air exhaust noise are noise signals generated by the housing 100 when air is intake and exhaust, respectively, and fan blade noise and motor noise are noise signals generated by the fan blades 220 and motor 210 of the fan assembly 200 when they are running.

[0086] Specifically, during the operation of the fan assembly 200, the air inlet 102 and air inlet shroud 104 of the housing 100 will draw in a large amount of air, resulting in a corresponding amount of intake noise from the air inlet shroud 104 and the outer contour of the air inlet. Alternatively, during the operation of the fan assembly 200, the air outlet 103 and air outlet shroud 105 of the housing 100 will also expel a large amount of air, resulting in a corresponding amount of exhaust noise from the air outlet shroud 105 and the outer contour of the air outlet. Alternatively, during the operation of the fan assembly 200, the rotation of the fan blades 220 will interact with the air, generating pressure pulsations and thus producing a corresponding amount of fan blade noise. Alternatively, during the operation of the fan assembly 200, when the rotor of the motor 210 cuts magnetic lines of force, friction between the rotor and stator will generate a corresponding amount of motor noise. Therefore, the four main static noise signals mentioned above will dynamically combine into a comprehensive noise signal and be transmitted to the user's hearing system during the use of the noise-canceling fan 10 (e.g., when the user is walking, running, or remaining stationary while holding the noise-canceling fan 10). In some embodiments, the signal acquisition unit 310 follows the user's usage scenario, collects the comprehensive noise signal dynamically composed of the aforementioned intake noise, exhaust noise, fan blade noise, and / or motor noise in real time, and sends it to the signal processor 320 for detailed analysis and processing.

[0087] In some embodiments, the intake noise includes static intake noise generated by the portable active noise-canceling fan 10 when used in a fixed position and dynamic intake noise generated when the user shakes the fan; the exhaust noise includes static exhaust noise generated by the portable active noise-canceling fan 10 when used in a fixed position and dynamic exhaust noise generated when the user shakes the fan; the fan blade noise includes static fan blade noise generated by the portable active noise-canceling fan 10 when used in a fixed position and dynamic fan blade noise generated when the user shakes the fan; the motor noise includes static motor noise generated by the portable active noise-canceling fan 10 when used in a fixed position and dynamic fan blade noise generated when the user shakes the fan.

[0088] Specifically, in practical applications of this portable active noise-canceling fan 10, it can have multiple usage states, and the corresponding dynamic composite noise signal generated in each usage state is different. For example, when a user places it on a desktop as a desktop fan, the portable active noise-canceling fan 10 is in a stationary state, and the corresponding dynamic composite noise signal generated is static noise. Or, when a user holds it in their hand and moves it at irregular speeds and directions, the portable active noise-canceling fan 10 is in an irregular operating state, and the corresponding dynamic composite noise signal generated is dynamic noise.

[0089] In some embodiments, after the signal acquisition unit 310 acquires the noise signal, the noise signal is transmitted to the signal processor 320. The signal processor 320 can extract features such as amplitude, frequency and phase in the noise signal and generate a signal generation instruction based on the acquired noise signal. The signal generation instruction can instruct the signal generator 330 to issue a noise reduction signal to eliminate the noise signal.

[0090] In one embodiment, within a preset error tolerance range, the noise reduction signal is out of phase and has the same frequency and amplitude as the noise signal, and is used to perform destructive interference on the noise signal to achieve active noise control of the fan assembly 200.

[0091] Specifically, sound is composed of a certain spectrum. The spectrum of the noise reduction signal is exactly the same as the noise signal to be eliminated, but the phase is exactly opposite. That is, a phase difference of 180° can completely cancel out the noise signal. In this way, after the noise reduction signal interferes with and interferes with the sound, the new sound wave generated can be so weak that it is inaudible to the human ear, thereby reducing the impact of motor noise on humans.

[0092] It should be understood that signal acquisition equipment or environmental noise measurement may be affected by external factors, such as background noise and temperature changes, which may lead to inaccurate signal acquisition. Different noise reduction algorithms have their applicable ranges and limitations, and some algorithms may not be able to effectively handle noise in all frequency ranges, resulting in inaccurate noise reduction signal generation. Alternatively, the structure around the fan (such as walls, the ground, and other objects) may affect the propagation characteristics of sound waves, producing reflection, diffraction, or resonance, thereby changing the signal acquisition effect. Ultimately, this may result in the generated noise reduction signal not being completely 180° out of phase with the noise signal, and / or not having the same frequency and amplitude. Therefore, a preset error allowable range can be set. As long as the generated noise reduction signal and the noise signal are within this error allowable range, they are considered to be out of phase and have the same frequency and amplitude.

[0093] In some embodiments, the signal processor 320 can simultaneously receive noise signals acquired by the multi-channel signal acquisition unit 310, and can also output multi-channel signal generation instructions to the signal generator 330. That is, a noise-reducing fan 10 may include multiple noise-reducing components 300.

[0094] The noise reduction component 300 can receive and transmit signals wirelessly or via wired means, meaning that the noise reduction component 300 can simultaneously perform active noise reduction control on multiple target areas in the noise reduction fan 10.

[0095] Specifically, in one possible implementation, both the signal acquisition unit 310 and the signal generator 330 are electrically connected to the signal processor 320, which is configured to control the signal acquisition unit 310 to acquire noise signals and control the signal generator 330 to play noise-reduced signals.

[0096] Therefore, the signal processor 320 can control multiple signal acquisition units 310 to acquire noise signals. After the signal processor 320 performs feature extraction and analysis on the acquired noise signals and generates a signal generation command, the signal processor 320 can control multiple signal generators 330 to play the corresponding noise reduction signals, thereby canceling the noise signals.

[0097] In another possible implementation, the noise reduction component 300 provided in this application embodiment may further include a wireless communication component, and the signal processor 320, signal acquisition unit 310 and signal generator 330 are all electrically connected to the wireless communication component.

[0098] In this way, the signal processor 320 can send signal generation commands to multiple signal acquisition units 310 and multiple signal generators 330 via wireless communication, making the noise reduction component 300 easier to use.

[0099] In a specific implementation, the wireless communication component includes at least one of a Bluetooth module, a WiFi module, and a 5G module.

[0100] To facilitate signal transmission, the wireless communication component employs wireless communication, which may include one or more of Bluetooth, WiFi, and 5G modules. A WiFi module is included in the wireless communication component to directly connect the signal processor 320, signal collector 310, and signal generator 330 to the internet, enabling communication between them. A Bluetooth module is a short-range wireless communication technology that replaces data cables. Bluetooth supports point-to-point and point-to-multipoint communication. The Bluetooth module wirelessly connects the signal processor 320, signal collector 310, and signal generator 330 into a micro-network, enabling fast and convenient communication between these modules. 5G is a next-generation broadband mobile communication technology characterized by high speed, low latency, and massive connectivity. Including a 5G module in the wireless communication component allows for interconnection of the signal processor 320, signal collector 310, and signal generator 330, enabling rapid communication between them. In specific implementations, the configuration can be tailored to the actual usage; this embodiment does not impose any limitations.

[0101] In a specific implementation scenario, the working principle of the noise-reducing fan 10 can be as follows: When the noise-reducing fan 10 starts, the main controller initializes all components; then, the signal processor 320 reads at least one noise signal sent by the signal acquisition unit 310. If no noise signal is detected, the detection continues. If a noise signal is detected, the signal processor 320 first uses FFT transformation to analyze the frequency, amplitude, and phase of each noise signal. Then, based on the analyzed frequency, amplitude, and phase of the noise, it generates a signal generation command and sends the command to the corresponding matching signal generator 330, instructing the signal generator 330 to emit a noise-reducing signal with the same frequency and amplitude as the noise signal but with opposite phase, in order to eliminate the noise signal.

[0102] The technical advantages of the above solution are as follows: On the one hand, by housing the fan assembly and noise reduction assembly within a portable casing, the physical size of the fan is greatly reduced, making the device easy to carry and suitable for use in various occasions, thus improving the portability and operability of the active noise-canceling fan; on the other hand, by differentiating itself from existing technologies, this solution, through the rational design of the noise reduction assembly's functions, can dynamically analyze various noise signals, including intake noise, exhaust noise, fan blade noise, and / or motor noise. This allows for the real-time acquisition of dynamic comprehensive noise signals generated inside and outside the cavity during fan assembly operation, and the issuance of corresponding noise reduction signals based on these dynamic comprehensive noise signals, thereby achieving active noise control of the fan assembly to reduce the noise level during fan operation.

[0103] Those skilled in the art will understand that the portable active noise-canceling fan shown in Figures 1 to 4 is merely a block diagram of a portion of the structure related to the solution of this application, and does not constitute a limitation on the noise-canceling fan used thereon in the solution of this application. The specific noise-canceling components may include more or fewer parts than shown in the figures, or combine certain parts, or have different part arrangements.

[0104] In one embodiment, the signal acquisition device 310 includes at least one sound sensor 311; wherein the at least one sound sensor 311 is disposed at at least one target point within the cavity 101 to collect noise signals near each target point in real time.

[0105] The sound sensors 311, distributed at various target points within the cavity 101, are used to collect noise signals generated by relevant parts of the fan assembly 200 during operation. For example, during the operation of the fan assembly 200, the fan blades 220 rotate and interact with the air, generating pressure pulsations and thus producing noise of a corresponding magnitude. Alternatively, the torque generated by the fan blades 220 is transmitted to the motor 210 through the transmission mechanism, also generating noise of a corresponding magnitude, mainly including bearing noise, gear noise, and motor noise. Furthermore, when the rotor of the motor 210 cuts magnetic lines of force, friction between the rotor and stator generates noise of a corresponding magnitude. Or, under strong winds, a short circuit in the motor 210 can also produce abnormal noise, as can aerodynamic noise generated by high-speed airflow, unstable airflow, and the interaction between the airflow and the blades 222. Therefore, the sound sensors 311 at various locations can be used to collect the aforementioned noise signals.

[0106] In some embodiments, the target location includes at least the edge of the air inlet 102, the edge of the air outlet 103, the vicinity of the motor 210, the vicinity of the fan blade 220, and the vicinity of the air duct center 106.

[0107] Specifically, as shown in Figure 3, since the noise of the fan assembly 200 is mainly generated when the fan blades 220 rotate, in one possible implementation, multiple sound sensors 311 include a first microphone 311a and a second microphone 311b. The first microphone 311a is disposed on the blades 222 of the fan blades 220 and is configured to collect the noise signal of the blades 222 of the fan blades 220. The second microphone 311b is disposed on the hub 221 of the fan blades 220 and is configured to collect the noise signal of the hub 221.

[0108] In this way, the first microphone 311a can collect the noise signal of the blades 222 of the fan blade 220 and transmit the noise signal to the signal processor 320 to extract the amplitude, frequency, and phase characteristics of the noise signal. The signal generator 330 then generates a noise reduction signal to cancel the noise signal, thereby partially or completely eliminating the noise signal generated by the blades 222 of the fan blade 220 during rotation. Similarly, the second microphone 311b can collect the noise signal of the hub 221 of the fan blade 220 and transmit the noise signal to the signal processor 320 to extract the amplitude, frequency, and phase characteristics of the noise signal. Based on these characteristics, the signal generator 330 generates a noise reduction signal to cancel the noise signal, thereby partially or completely eliminating the noise signal generated by the hub 221 of the fan blade 220 during rotation.

[0109] As shown in Figure 3, in addition to the significant noise generated by the hub 221 and blades 222 during rotation, noise signals are also generated by the rotor assembly 212 of the motor 210 cutting magnetic lines of force and by friction between the rotor assembly 212 and the stator assembly 211. In some embodiments, the plurality of sound sensors 311 further include a third microphone 311c, which is disposed on the inner wall near the motor 210 within the cavity 101 and configured to collect noise signals from the motor 210.

[0110] Thus, the third microphone 311c can collect the noise signal of the motor 210 of the fan assembly 200 and transmit the noise signal to the signal processor 320 to extract the amplitude, frequency and phase characteristics of the noise signal, and generate a noise reduction signal to cancel the noise signal based on these characteristics using the signal generator 330, thereby partially or completely eliminating the noise signal generated by the motor 210 of the fan assembly 200 during operation.

[0111] In other embodiments, although the related technology reduces the noise generated when air flows in the cavity 101 by improving the structure of the fan housing 120, some noise will still inevitably be generated when air flows in the cavity 101. Therefore, in some embodiments, the plurality of sound sensors 311 also include a fourth microphone 311d, which is respectively disposed on the inner wall near the air inlet 102, the air outlet 103 and the center of the air duct 106 in the cavity 101, and is configured to collect noise signals from the air inlet 102, the air outlet 103 and the center of the air duct 106.

[0112] Thus, the fourth microphone 311d can collect noise signals generated when air flows in the cavity 101 and transmit the noise signals to the signal processor 320 to extract the amplitude, frequency and phase characteristics of the noise signals. Based on these characteristics, the signal generator 330 generates a noise reduction signal to cancel the noise signals, thereby eliminating the noise signals generated in the air inlet 102, air outlet 103 and air duct center 106 in the cavity 101 when the fan assembly 200 is running.

[0113] In one embodiment, as shown in FIG5, the signal processor 320 includes a filter 321, a signal synthesizer 322, a signal amplifier 323, an analog-to-digital converter 324, and a computer chip 325 connected in sequence.

[0114] Among them, the filter is used to perform real-time filtering processing on the static noise signals collected by each sound sensor to obtain the filtered noise signal;

[0115] In some embodiments, filtering is used to resolve frequency aliasing in audio signals. When discretizing analog signals, a low-pass filter can be used to sample the signals to obtain filtered noise signals.

[0116] In other embodiments, the signal processor 320 includes at least a plurality of filters 321. These filters 321 include, but are not limited to, IIR (Infinite Impulse Response) filters and biquad filters. Since biquad filters integrate the characteristics of, for example, high-pass filters, low-pass filters, frequency equalization filters, and notch filters, the combination of these filters 321 achieves the reduction of noise frequencies in the noise signal, thus achieving the initial purpose of reducing specific noise signals.

[0117] The signal synthesizer 322 is used to perform signal fusion processing on each filtered noise signal to obtain a dynamically composed comprehensive noise signal.

[0118] Specifically, the signal synthesizer 322 can transcode the multi-channel filtered noise signals into a single composite noise signal according to an object-based audio encoding method. In some embodiments, the signal synthesizer 322 is used to re-encode the multi-channel filtered noise signals according to the NGA audio encoding format (i.e., object-based audio encoding method), that is, to transcode the multi-channel filtered noise signals. In this way, all the noise signals are merged into a single composite noise signal, so that only one decoder is needed for decoding during signal amplification. The object-based audio encoding method can be AC-4, MPEG-H, DTS-UHD, but is not limited to these.

[0119] In one embodiment, multiple filtered noise signals can be dynamically transcoded and fused into a single composite noise signal using an audio mixer or audio interface. The core principle of this audio mixer or interface is to dynamically generate a composite audio signal by combining, adjusting, and processing the amplitude and frequency response of multiple filtered static noise signals. In this way, multiple noise sources can be mixed in a balanced manner without loss of sound quality, thus achieving an ideal noise reduction effect.

[0120] In some embodiments, this mixer is specifically designed for mixing multiple audio signals. Its basic functions include: ① Each input signal from its input channels can be connected to the mixer via an independent channel. ② Each input channel is equipped with a volume knob to adjust the volume ratio of different signals. ③ It is equipped with an equalizer to adjust the gain of each frequency band to optimize sound quality. ④ It dynamically synthesizes all adjusted signals together internally into a single, integrated output signal, which is then output through the mixer's output port, which can be connected to devices such as speakers.

[0121] In some embodiments, this audio interface is used to convert multiple audio signals into digital signals and connect to a computer or other digital audio processing device. Its basic functions include: ① supporting multi-channel input connections from multiple audio sources. ② internally including a converter to convert analog audio signals into digital signals, and potentially performing some basic mixing processing. ③ it can be used with a digital audio workstation (DAW), allowing users to adjust mixing within the software, such as volume, panning, and effects, with a final output as a single path.

[0122] Among them, the signal amplifier 323 is used to amplify the comprehensive noise signal to obtain the comprehensive amplified signal.

[0123] In some embodiments, the signal amplifier 323 is used to enhance the amplitude of the composite noise signal to improve its strength and quality during transmission, processing, or output. The signal amplifier 323 can be an audio amplifier or an radio frequency amplifier, capable of amplifying minute noise signals to a sufficient level for subsequent processing or output. Furthermore, by reducing noise and distortion, the signal amplifier 323 can improve the clarity and reliability of the noise signal. Additionally, the signal amplifier 323 can aid in signal matching between different devices, ensuring their effective operation.

[0124] The analog-to-digital converter 324 is used to perform analog-to-digital conversion on the amplified signal to obtain the corresponding pulse code signal.

[0125] In some embodiments, the pulse-coded signal is an audio pulse-code modulation (PCM) signal.

[0126] Specifically, the analog-to-digital converter 324 (ADC) is an electronic device or circuit that converts analog signals into digital signals. This process, called analog-to-digital conversion, aims to enable analog signals (i.e., amplified signals) to be processed by a digital computer or computer chip 325.

[0127] In some embodiments, the basic steps of analog-to-digital conversion are as follows:

[0128] ① Input amplified signal: Typically, this amplified signal is an amplified analog signal, such as the output from an audio amplifier, temperature sensor, or other sensor.

[0129] ② Sampling: The analog-to-digital converter 324 detects the input analog signal at a certain sampling frequency. This frequency needs to be higher than the Nyquist frequency of the signal (generally twice the signal frequency) to ensure signal integrity.

[0130] ③ Quantization: Converting the sampled analog signal values ​​into discrete digital values. Quantization errors may occur at this stage.

[0131] ④ Encoding: The quantized value is encoded into a digital signal, usually in binary encoding form (such as pulse code modulation, PCM), and output as a digital signal.

[0132] In some embodiments, Pulse Code Modulation (PCM) is a digital signal representation method widely used in the digital representation of audio, video, and other analog signals. Its characteristics include: signal discretization: PCM converts continuous analog signals into a series of discrete digital values ​​through sampling and quantization; energy efficiency and bandwidth efficiency: digital signals encoded with PCM are less susceptible to noise interference during transmission, and compression techniques can reduce transmission bandwidth.

[0133] The computer chip 325 is used to perform phase inversion processing on the pulse code signal to obtain inverted signal data, and to generate a signal generation command based on the inverted signal data.

[0134] In one embodiment, the audio generation instruction includes pulse-coded data that is out of phase with the pulse-coded signal but has the same frequency and amplitude.

[0135] In some embodiments, the computer chip 325 can determine the spectral range and magnitude of the pulse-coded signal by analyzing the Hanning window spectrum of the pulse-coded signal, and calculate the corresponding inverted signal data.

[0136] Specifically, when analyzing the spectrum of pulse-coded signals, using the Hanning window is an effective method to reduce spectral leakage and improve the accuracy of spectrum estimation. The steps are as follows:

[0137] 1. Signal preprocessing

[0138] Before processing the pulse-coded signal, the computer chip 325 applies a Hanning window function to window the original signal. This can be achieved using the following formula:

[0139] Where N is the length of the signal.

[0140] 2. Calculate the spectrum

[0141] The computer chip 325 performs a Fast Fourier Transform (FFT) on the signal processed by the window function to calculate the spectrum. This Fast Fourier Transform can be implemented using the following formula:

[0142] Where X[k] is the spectrum and x[n] is the time-domain signal after window function processing.

[0143] 3. Extract frequency and amplitude

[0144] The computer chip 325 performs spectral analysis on the spectrum based on the FFT results to extract the frequency and amplitude of the signal.

[0145] The steps include:

[0146] First, calculate the amplitude spectrum: Then find the main frequency components and their corresponding amplitudes.

[0147] 4. Calculate the inverted signal data

[0148] Computer chip 325 calculates inverted signal data: To obtain an inverted signal with opposite phase, first determine the amplitude A and phase □ of a certain frequency f. This inverted signal can be represented as:

[0149] A 反 =A,φ 反 =φ+π;

[0150] This means that if the original signal is represented by the complex number X = Ae at frequency f: jφ ;

[0151] Therefore, the inverted signal data can be represented as: X 反 =Ae j(φ+π) =-Ae jφ .

[0152] 5. Applying inverted signal data

[0153] The computer chip 325 generates a signal generation command based on the inverted signal data. When the inverted signal in the signal generation command is superimposed with the noise signal, they will cancel each other out within the same frequency range, thereby achieving the effect of noise reduction or interference suppression.

[0154] In some embodiments, the computer chip 325 can be an integrated circuit chip with signal processing capabilities. The aforementioned computer chip 325 can be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it can also be a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), an embedded ARM, or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. The general-purpose processor can be a microprocessor; the computer chip 325 can also be any conventional processor, etc., and is not specifically limited in this application.

[0155] In one embodiment, the signal generator 330 includes at least one sound player 331 and a power amplifier 332 disposed at each target point;

[0156] Among them, the power amplifier 332 is used to amplify the inverted signal data carried by the signal generation command to obtain the power amplified signal;

[0157] Specifically, the power amplifier 332 includes a power amplifier circuit, which includes a signal input terminal and a signal output terminal. The signal input terminal of the power amplifier circuit is electrically connected to the computer chip 325. The computer chip 325 includes multiple signal output ports for outputting the generated signal generation command. The signal input terminal of the power amplifier circuit is electrically connected to the signal output port of the computer chip 325. The signal output terminal of the power amplifier circuit is electrically connected to the sound player 331. The power amplifier circuit is used to amplify the inverted signal data generated by the computer chip 325, which has the opposite phase and the same amplitude as the acquired noise.

[0158] The sound player 331 is used to emit a noise reduction signal that is opposite in phase to the combined noise signal but has the same frequency and amplitude, based on the power amplification signal.

[0159] Specifically, after the computer chip 325 calculates the inverted signal data, it needs to be played out by the sound player 331 so that the noise reduction signal interferes with or interferes with the noise signal, thereby canceling out part or all of the noise signal.

[0160] In some embodiments, the signal generator 330 converts the inverted signal data input from the computer chip 325 into analog signals and amplifies the signal before outputting it to the sound player 331. This inverted signal data is mainly used to suppress noise signals from the original environment; this process is called active noise cancellation, and the principle of active noise cancellation is shown in Figure 6.

[0161] Therefore, the signal generator 330 may include multiple sound players 331, and the sound players 331 and the sound sensor 311 are in a one-to-one correspondence in position, so that the noise reduction signals played by different sound players 331 can eliminate the corresponding noise signals.

[0162] Specifically, as shown in Figure 3, since the noise of the fan assembly 200 is mainly generated when the fan blades 220 rotate, in one possible implementation, the multiple sound players 331 include a first speaker 331a and a second speaker 331b. The first speaker 331a is disposed on the blades 222 of the fan blades 220 and is configured to play an inverted noise-canceling signal to the rotating blades 222. The second speaker 331b is disposed on the hub 221 of the fan blades 220 and is configured to play an inverted noise-canceling signal to the rotating hub 221.

[0163] In this way, the first speaker 331a can generate instructions from the computer chip 325 to play an inverted noise-reducing signal to the rotating blade 222 to cancel the noise signal generated in the target area, thereby partially or completely eliminating the noise generated by the blade 222 of the fan blade 220 when rotating. Similarly, the second speaker 331b can generate instructions from the computer chip 325 to play an inverted noise-reducing signal to the rotating hub 221 to cancel the noise signal generated in the target area, thereby partially or completely eliminating the noise generated by the hub 221 of the fan blade 220 when rotating.

[0164] As shown in Figure 3, in addition to the significant noise generated by the hub 221 and blades 222 during rotation, noise signals are also generated by the rotor assembly 212 of the motor 210 cutting magnetic lines of force and by friction between the rotor assembly 212 and the stator assembly 211. In some embodiments, the multiple sound players 331 also include a third speaker 331c, which is disposed on the inner wall near the motor 210 within the cavity 101 and configured to play an anti-phase noise-reducing signal to the operating motor 210.

[0165] Thus, the third speaker 331c can generate instructions based on the signal sent by the computer chip 325 to play an inverse noise reduction signal to the running motor 210 to cancel the noise signal generated in the target area, thereby partially or completely eliminating the noise generated by the motor 210 of the fan assembly 200 during operation.

[0166] In other embodiments, although the related art reduces the noise generated when air flows in the cavity 101 by improving the structure of the fan housing 120, some noise is still inevitably generated when air flows in the cavity 101. Therefore, in some embodiments, the plurality of sound players 331 also include a fourth speaker 331d, which is respectively disposed on the inner wall near the air inlet 102, the air outlet 103 and the center of the air duct 106 in the cavity 101, and is configured to play an inverse noise-reducing signal to the target area near the air inlet 102, the air outlet 103 and the center of the air duct 106.

[0167] Thus, the fourth speaker 331d can generate instructions based on the signals sent by the computer chip 325 to play inverse noise reduction signals to the target areas near the air inlet 102, air outlet 103 and air duct center 106 respectively, so as to cancel the noise signals generated in the target areas, thereby eliminating the noise generated in the air inlet 102, air outlet 103 and air duct center 106 in the cavity 101 when the fan assembly 200 is running.

[0168] In other embodiments, the sound player 331 for each target area may also include a plurality of noise-canceling speakers, and at least two of the noise-canceling speakers are oriented differently.

[0169] In other words, when collecting noise signals, multiple signal collectors 310 will collect noise signals from different parts of the fan assembly 200. In order to specifically cancel different noise signals, different cancellation sound wave signals need to be generated and played according to the propagation direction of different noise signals. Therefore, during playback, the propagation direction of the noise reduction signal for different noise signals will also be different. Thus, the sound playback direction of multiple noise reduction speakers is different to eliminate noise signals propagating from various directions.

[0170] In some implementations, the number of noise-canceling speakers can be an even number, with multiple noise-canceling speakers arranged in a circle, and the orientations of two opposing noise-canceling speakers facing away from each other.

[0171] For example, the number of noise-canceling speakers can be four or six. When there are four noise-canceling speakers, adjacent speakers are arranged at a 90-degree angle, and all speakers face outwards. When there are six noise-canceling speakers, adjacent speakers are arranged at a 60-degree angle, and opposite speakers face back to back. In this way, multiple noise-canceling speakers can play noise-canceling wave signals in all directions to better eliminate noise.

[0172] In one embodiment, referring to Figures 7 and 8, the signal processor 320 further includes an amplitude comparator 326, the input of which is electrically connected to an analog-to-digital converter 324, and the output of which is electrically connected to a computer chip 325.

[0173] The amplitude comparator 326 is used to acquire the pulse code signal and extract the corresponding noise amplitude sequence from the pulse code signal, so as to compare the noise amplitude sequence with the preset amplitude threshold to obtain the first comparison result.

[0174] In some embodiments, the computer chip 325 is further configured to acquire a first comparison result, and when the first comparison result is that the noise amplitude sequence is greater than the amplitude threshold, to perform phase inversion processing on the pulse-coded signal to obtain inverted signal data, or to end the noise reduction process when the first comparison result is that the noise amplitude sequence is less than or equal to the amplitude threshold.

[0175] Specifically, the amplitude comparator 326, analog-to-digital converter 324, and computer chip 325 mentioned above can form an automated signal processing system 340 based on amplitude comparison and active noise reduction. The following will provide a detailed analysis of each part of this automated signal processing system 340 and its workflow.

[0176] 1. Introduction to System Components

[0177] Analog-to-digital converter 324 (ADC): Used to convert analog signals (i.e., combined noise signals) into digital signals for subsequent processing modules.

[0178] Amplitude Comparator 326: Used to acquire the pulse-coded signal from the analog-to-digital converter. It extracts the amplitude sequence of noise and compares it to a preset amplitude threshold. This process allows the system to determine whether noise reduction measures are needed given the current noise level.

[0179] Computer Chip 325: Receives the first comparison result from the amplitude comparator and executes corresponding logic operations. Based on the comparison result, it determines whether to perform phase inversion processing on the pulse-coded signal, thereby generating inverted signal data for active noise reduction.

[0180] 2. System Workflow

[0181] Signal input and conversion: The noise signal is first converted into a digital pulse code signal by the analog-to-digital converter 324, which is then used by the amplitude comparator 326.

[0182] Amplitude extraction and comparison: Amplitude comparator 326 extracts the amplitude sequence of noise from the pulse-coded signal. The extracted amplitude sequence is then compared with a preset amplitude threshold to generate a first comparison result: if the amplitude sequence is greater than the threshold, noise reduction processing is required; if the amplitude sequence is less than or equal to the threshold, the noise reduction process ends.

[0183] Phase Inversion Signal Generation: If the first comparison result indicates that the noise amplitude sequence is greater than the amplitude threshold, the computer chip 325 will initiate phase inversion processing, including processing the pulse-coded signal to generate phase inversion signal data. This phase inversion signal data is used for active noise reduction to cancel the original noise signal.

[0184] Program termination: If the first comparison result shows that the noise amplitude sequence is less than or equal to the set amplitude threshold, the noise reduction program will be terminated and signal processing will be stopped.

[0185] The processing logic of the automated signal processing system 340 is such that, as long as the fan noise does not affect the user experience or use, the automated signal processing system 340 may not process the fan noise. This is beneficial for the energy saving of the noise-reducing fan 10, especially when the current battery level of the noise-reducing fan 10 is low, it can further extend the standby time. Therefore, the automated signal processing system 340 can determine whether to reduce fan noise based on the amplitude value of the current noise signal. If the current fan noise is insufficient to affect the user experience or use, active noise reduction will not be performed; otherwise, active noise reduction will be performed.

[0186] 3. System Functions

[0187] Automated control: The automated signal processing system 340 effectively generates an automated response program that can adjust noise reduction strategies according to real-time changes in ambient noise.

[0188] Precise noise reduction: Through amplitude comparison and phase inversion technology, active noise reduction improves the working efficiency of the noise-reducing fan 10 under different noise conditions.

[0189] 4. System Settings

[0190] Threshold setting: Setting an appropriate amplitude threshold for the automated signal processing system 340 is crucial. Setting it too high may lead to unnecessary noise reduction; setting it too low may lead to frequent noise reduction and unnecessary processing delays.

[0191] Latency impact: The signal processing delay of the automated signal processing system 340 may affect the noise reduction effect. Therefore, the automated signal processing system 340 can be connected to the cloud to optimize the signal processing speed and ensure real-time performance.

[0192] The technical advantage of the above solution is that by combining signal processing and intelligent control technologies through an automated signal processing system, it can adapt to complex and ever-changing noise environments.

[0193] In one embodiment, referring to Figures 7 and 9, the signal processor 320 further includes a decibel comparator 327, the input of which is electrically connected to the signal acquisition unit 310, and the output of which is electrically connected to the computer chip 325.

[0194] The decibel comparator 327 is used to acquire the residual noise signal collected in real time by the signal acquisition unit 310 after the signal generator 330 emits the noise reduction signal, and extract the corresponding noise decibel value from the residual noise signal to compare the noise decibel value with the preset decibel threshold to obtain the second comparison result.

[0195] In some embodiments, the computer chip 325 is further configured to obtain a second comparison result, and when the second comparison result is that the noise decibel value is greater than the decibel threshold, to reduce the speed of the motor 210 of the fan assembly 200, or to end the noise reduction process when the second comparison result is that the noise decibel value is less than or equal to the decibel threshold.

[0196] Specifically, in order to more accurately determine the impact of fan noise on user experience, the decibel value of the fan noise can be obtained. The decibel value of the fan noise can be used to determine whether the fan is operating normally, thus further avoiding the problem of decreased user experience caused by fan malfunction.

[0197] In some embodiments, the automated signal processing system 340 described above may also include a decibel comparator 327, thereby further improving the active noise reduction technology. The following will provide a detailed analysis of the various parts of the automated signal processing system 340 and its workflow.

[0198] 1. Introduction to System Components

[0199] Signal Collector 310: Used to collect residual noise signals in the environment in real time, including noise that still exists after the noise reduction signal is released by the signal generator.

[0200] Decibel Comparator 327: Used to receive noise signals from signal acquisition unit 310, extract the corresponding noise decibel values, compare them with a preset decibel threshold, and generate a second comparison result.

[0201] Computer Chip 325: Used to receive the second comparison result from the decibel comparator output and execute control logic to adjust the speed of fan motor 210 to achieve further noise reduction.

[0202] 2. System Workflow

[0203] Signal acquisition: After the signal generator 330 emits a noise reduction signal, the signal acquisition unit 310 begins to monitor the residual noise in the environment in real time.

[0204] Decibel Extraction and Comparison: The decibel comparator 327 extracts the decibel value of the noise from the acquired signal. It then compares the extracted decibel value with a preset decibel threshold and outputs a second comparison result. If the decibel value is greater than the threshold, it indicates that the residual noise is still strong, and the power or speed of the noise-generating equipment needs to be reduced. If the decibel value is less than or equal to the threshold, it indicates that the noise has been reduced to an acceptable level, and the noise reduction process can be terminated.

[0205] Fan motor control: If the second comparison result indicates that the noise decibel value is greater than the decibel threshold, the computer chip 325 will send a control signal to reduce the speed of the motor 210 of the fan assembly 200. This process can effectively reduce the noise generated by the motor operation.

[0206] Program termination: If the second comparison result shows that the noise decibel value is less than or equal to the decibel threshold, the program will terminate and no further noise processing will be performed.

[0207] 3. System Functions

[0208] Dynamic adjustment: The automated signal processing system 340 can dynamically adjust the speed of the fan motor 210 according to the changes in real-time residual noise, ensuring that the volume is kept to a minimum under various environmental conditions.

[0209] Analogous feedback: Through comparison and real-time feedback, the automated signal processing system 340 can effectively manage and control the response of different noise sources, enhancing the effect of active noise reduction.

[0210] 4. System Settings

[0211] Decibels Threshold Setting: A reasonable decibel threshold setting is crucial for the success of the automated signal processing system 340. A threshold that is too high may cause the fan to slow down ineffectively, while a threshold that is too low may fail to effectively cope with real-world noise environments.

[0212] Fan response time: The computer chip 325 needs to respond as quickly as possible to control the motor 210 in order to adapt to the instantaneous changes in environmental noise and thus achieve timely noise reduction.

[0213] The technical advantages of the above solution are: by combining intelligent monitoring, real-time feedback and automatic control technologies through the automated signal processing system 340, it can effectively cope with environmental noise and provide a more comfortable user experience.

[0214] In some embodiments, to further improve energy efficiency, if the automated signal processing system 340 determines that the residual noise in the environment is not less than a preset decibel value, noise reduction of the fan may not be performed. In specific applications, the automated signal processing system 340 can detect the current usage scenario of the noise-reducing fan 10. If the background noise (including user voice) is high, noise reduction will not be activated, because activating noise reduction will definitely consume more power. Therefore, this method can further reduce the power consumption of the mobile phone.

[0215] In other embodiments, to further ensure the stable operation of the noise-reducing fan 10 under low battery conditions, the automated signal processing system 340 can also determine whether the current battery level of the noise-reducing fan 10 is lower than a preset battery level; if so, the built-in motor 210 of the noise-reducing fan 10 is started; otherwise, an alarm prompting that the battery level is too low is issued. Therefore, when the battery level is lower than the preset battery level, the automated signal processing system 340 controls the fan not to turn on and can prompt the user to remind them.

[0216] In one implementation of this application, the step of the automated signal processing system 340 to reduce fan noise based on residual signals may include: when the noise signal contains user voice signals, using a preset noise recognition model to identify the fan noise and obtain a noise signal after voice recognition; and then reducing the noise signal after voice recognition. For example, during user operation, interactions between multiple users often occur, requiring voice input. To further improve fan noise recognition and avoid eliminating user voice information, fan noise recognition is necessary. Specifically, the noise recognition model is established by: determining positive and negative input samples, where the positive samples are a noise training set and the negative samples are a voice training set; training with a PLDA model to obtain an average error; and determining a usable noise recognition model when the average error is less than a preset error. The PLDA model is trained using positive and negative samples. Once the model reaches a certain maturity level, the automated signal processing system 340 uses a noise recognition model to identify fan noise. This accurately identifies fan noise and reduces the error of mistakenly identifying user voice as fan noise for cancellation, thereby further improving the accuracy of fan noise cancellation and enhancing the user experience.

[0217] In this process, the signal acquisition unit 310 picks up the suppressed residual noise, which is an analog signal. Then, the signal processor 320 amplifies the acquired analog noise signal and filters out the high-frequency components of the signal using a low-pass filter. The high-frequency filtered signal is then converted from analog to digital and input into the automated signal processing system 340. This process generates low-frequency audio data, which is provided to the automated signal processing system 340 for further learning and evaluation of the active noise reduction effect.

[0218] In one embodiment, referring to FIG10, the signal processor 320 further includes an error acquisition element 328, which is disposed in the cavity 101 and electrically connected to the computer chip 325. The error acquisition element 328 is used to calculate the error between the noise signal and the noise reduction signal, obtain error signal data, and feed the error signal data back to the computer chip 325 so that the noise reduction signal can be calibrated by the computer chip 325.

[0219] The error acquisition unit 328 is configured to detect the error between the noise signal acquired by the signal acquisition unit 310 and the noise-reduced signal played by the signal generator 330.

[0220] Specifically, in order to improve the noise reduction effect of the noise reduction fan 10, the noise reduction fan 10 is also equipped with an error acquisition device 328. The error acquisition device 328 is used to detect the error between the noise signal acquired by the signal acquisition device 310 and the noise reduction wave signal played by the signal generator 330, and feeds it back to the computer chip 325 in the signal processor 320 to calibrate the noise reduction signal, so as to make the inverted signal data in the signal generation instruction generated by the computer chip 325 more in line with the noise reduction requirements.

[0221] In some embodiments, the error acquisition unit 328, the signal acquisition unit 310, the signal generator 330, and the computer chip 325 described above can form a signal feedback control system 350 based on a signal feedback control mechanism. This system 20 is used to improve the accuracy and effectiveness of the noise reduction system. The following will provide a detailed analysis of each part of this signal feedback control system 350 and its workflow.

[0222] 1. Introduction to System Components

[0223] Error Collector 328: Used to calculate the error between the two in real time, that is, the difference between the actual noise signal and the noise-reduced signal generated by the signal processor, generate error signal data and feed it back to the signal processor 320.

[0224] 2. System Workflow

[0225] Signal input: The noise signal is captured and input to the computer chip 325 for analysis and processing.

[0226] Noise reduction signal generation: The computer chip 325 generates a noise reduction signal based on the processed data, which aims to intervene in and reduce noise signals.

[0227] Error Calculation: The error acquisition unit 328 receives the noise signal and the denoised signal, and calculates the error signal data using mathematical algorithms (such as subtraction or other error assessment methods). The following formula can be used: Error signal data = Noise signal - Denoising signal.

[0228] Data feedback: The calculated error signal data will be fed back to the computer chip 325 to provide real-time information about the noise reduction effect.

[0229] Signal calibration: The computer chip 325 calibrates the noise reduction signal based on the feedback error signal data. Parameters such as the amplitude, phase, or frequency of the noise reduction signal can be adjusted to more effectively combat noise signals. The calibrated noise reduction signal is then output again to improve the system's noise reduction performance.

[0230] 3. System Functions

[0231] Real-time feedback: The signal feedback control system 350 can quickly respond to the noise reduction effect through the real-time feedback of the error acquisition element 328, thereby making necessary adjustments and improving the noise reduction accuracy.

[0232] Adaptive calibration: The signal processor 320 can dynamically adjust the noise reduction signal based on the error signal calculated in real time, adapting to different noise environments and improving the adaptability and effectiveness of active noise reduction.

[0233] 4. System Settings

[0234] Computational latency: The latency of the error calculation and feedback system 350 may affect the noise reduction effect. Therefore, the response time can be reduced by optimizing the algorithm.

[0235] Noise mode settings: Different noise signals may require different noise reduction strategies. Therefore, the signal processor 320 can be designed to flexibly handle various noise modes.

[0236] Environmental adaptability settings: Ensure that the signal feedback control system 350 maintains effective noise reduction under different environmental conditions (such as different types of noise, background changes, etc.).

[0237] The technical advantages of the above solution are as follows: by designing a feedback control system and utilizing the collaborative work of the error acquisition device and the computer chip, the performance and flexibility of the active noise cancellation system can be significantly improved. This design effectively ensures the real-time performance and accuracy of the noise-canceling signal, enhancing the user experience.

[0238] In one embodiment, referring to FIG11, the portable active noise-canceling fan 10 further includes a memory 400 disposed within the cavity 101, for storing a preset speed-to-noise comparison table 410 and a noise-canceling signal database 420; wherein, the speed-to-noise comparison table 410 is used to characterize the correspondence between the speed of the motor 210 in the fan assembly 200 and the noise signal generated by the fan assembly 200 accordingly; the noise-canceling signal database 420 is used to store noise-canceling signals that are opposite in phase to various preset noise signals but have the same frequency and amplitude.

[0239] The noise reduction component 300 is also used to acquire the real-time speed of the motor 210 when the fan assembly 200 is running, and to determine the target noise signal that matches the real-time speed according to the speed-noise comparison table 410, and to determine the target noise reduction signal that matches the target noise signal from the noise reduction signal database 420, so as to perform active noise control on the fan assembly 200 based on the target noise reduction signal.

[0240] In some embodiments, the memory 400 may be used to store software programs and various data. The memory 400 may primarily include a program storage area and a data storage area. The program storage area may store the operating system, applications required for at least one function (such as a sound playback function), etc.; the data storage area may store data created based on the use of the noise-canceling fan 10 (such as audio data), etc. Furthermore, the memory 400 may include high-speed random access memory, and may also include non-volatile memory, such as at least one disk storage device, flash memory device, or other volatile solid-state storage device.

[0241] According to embodiments of this application, the signal acquisition device 310 can be one or more devices for acquiring noise-related signals. In this application, the signal acquisition device 310 can acquire noise-related signals through two methods: a sound sensor 311 and a memory 400. Specifically, the signal acquisition device 310 is a device placed within a noise control target area around the motor 210 to acquire noise in real time, and the memory 400 is a storage device that pre-stores noise characteristic signals of the fan 10.

[0242] When the signal acquisition unit 310 acquires a noise signal through the sound sensor 311, the sound sensor 311 transmits the acquired noise signal back to the signal processor 320. The signal processor 320 analyzes the acquired noise signal and transmits it to the signal generator 330. Alternatively, the sound sensor 311 can directly transmit the acquired noise signal back to the memory 400 without going through the signal processor 320, and then acquire the target noise reduction signal through the noise reduction signal database 420. The sound sensor 311 can transmit noise-related signals wirelessly or via wired transmission, and the memory 400 can simultaneously receive or output multiple noise signals.

[0243] In one embodiment, when the signal acquisition unit 310 acquires a noise signal through the memory 400, the signal acquisition unit 310 first acquires the real-time rotational speed of the motor 210, and then sends the real-time rotational speed to the memory 400. Based on the rotational speed and noise comparison table 410, the target noise signal matching the real-time rotational speed is determined. Then, the target noise reduction signal matching the target noise signal is determined from the noise reduction signal database 420. Finally, the target noise reduction signal is sent to the sound player 331, and the sound player 331 plays the target noise reduction signal to cancel the noise of the target noise signal.

[0244] According to an embodiment of this application, the sound player 331 may include multiple speakers. Speakers come in many types, classified by transduction mechanism and structure as moving-coil (electrodynamic), capacitive (electrostatic), piezoelectric (crystal or ceramic), electromagnetic (spring-loaded), electro-ion, and pneumatic speakers, etc. The multiple speakers of the sound player 331 can be installed together at various angles on the motor nacelle and / or the fairing and / or the tower, forming multiple speaker assemblies, with the fixed portion of the speaker assembly built into the cavity 101. Each speaker can effectively control a fan-shaped area to cancel noise within the target noise control area. According to an embodiment of this application, for example, four sets of speaker assemblies are installed on both sides of the motor nacelle and both sides of the fairing. Each set of speaker assemblies includes three speakers, and each speaker can effectively control a fan-shaped area of ​​30 degrees. Therefore, each set of speaker assemblies covers an area of ​​90 degrees, and the four sets of speaker assemblies can achieve 360-degree omnidirectional coverage of the noise control area around the motor nacelle. Additionally, the multiple speakers of the audio player 331 can also be individually mounted on the steering gimbal of the motor 210. The steering gimbal, as described here, refers to a support device used to mount and secure multiple speakers and control their rotation direction. Steering gimbals include multi-axis and single-axis gimbals, typically embedded in the motor housing and / or fairing and / or tower, driving the multiple speakers to rotate and fully cover the noise control target area around the motor 210. The noise control target area is the area where the noise caused by the motor 210 needs to be reduced; this area can be located within a predetermined range around the motor 210.

[0245] In other embodiments, the computer chip 325 in the noise reduction component 300 can also retrieve predetermined filter parameters required to reduce or eliminate the target noise signal from the memory 400 when the signal acquisition unit 310 is triggered, and pre-configure the fan component 200 according to the filter parameters.

[0246] In this embodiment, the signal acquisition unit 310 triggers a corresponding filter to perform real-time filtering on the noise signal in response to the pre-configuration of the computer chip 325, thereby reducing or eliminating the amplitude of specific noise signal frequency bands contained in the noise signal, and thus obtaining a denoised audio signal. In this embodiment, the denoised audio signal is an audio pulse code modulation signal.

[0247] Specifically, the analog-to-digital converter 324 in the noise reduction component 300 receives the target noise signal matched by the memory 400 and performs analog-to-digital conversion to obtain the corresponding original audio pulse code modulation signal, and sends the original audio pulse code modulation signal to the computer chip 325. The computer chip 325 analyzes the original audio pulse code modulation signal in the frequency domain and determines the filter parameters corresponding to the target noise signal based on the analysis results.

[0248] In one embodiment, the portable active noise-canceling fan 10 includes at least a handheld fan for wireless use, a neckband fan for use around the neck, or a strap-on fan for use in a strap-on configuration.

[0249] Among them, the handheld wireless fan is a portable electric fan characterized by its wireless design, allowing users to use it without being restricted by a power cord, making it convenient to carry and use. It is a variation of the handheld mini fan, further emphasizing its wireless feature. The main functions of this handheld wireless fan include: ① Wireless portability: Powered by a built-in rechargeable battery, it can be used without being plugged in, suitable for various indoor and outdoor scenarios. ② Multiple wind speed options: This wireless mini fan offers multiple wind speed settings, allowing users to adjust the wind intensity as needed. ③ Convenient charging: This handheld wireless mini fan can be charged via a USB interface, making it convenient to connect to a power bank or computer for charging. ④ Multi-functional: This handheld fan can include additional functions, such as a misting function, LED light, or even a Bluetooth speaker. ⑤ Easy storage: Its lightweight design makes it easy to put in a bag, ideal for travel use. The main features of this handheld wireless fan include: ① Lightweight design: This handheld fan can be made of lightweight materials, weighing between 200 grams and 500 grams, making it easy to hold for extended periods. ② High Safety: This handheld fan can be designed with either a bladeless bladeless design or an anti-pinch design to ensure safe use. ③ Stylish Appearance: This fan features a modern design with various colors and shapes to meet the fashion needs of young people. ④ Quiet Operation: The fan has an optimized motor and fan design, resulting in low noise during operation, making it ideal for users who require a quiet environment. ⑤ Long Battery Life: The built-in battery provides several hours of continuous use, meeting daily needs. Therefore, this handheld, wireless fan is perfect for use in hot weather, especially for enjoying a comfortable breeze during outdoor activities, travel, or simply at home.

[0250] Neckband fans are portable fans that can be worn around the neck. This design allows the fan to be close to the body, providing a more direct cooling effect, making it ideal for hot summers or outdoor activities. The main functions of a neckband fan include: ① Hands-free use: Because it hangs around the neck, the user's hands are free to use, without having to hold the fan. ② Portability: Its lightweight design makes it easy to carry, suitable for use in various occasions such as travel, sports, and work. ③ Multiple wind speeds: The neckband fan offers multiple wind speed settings, allowing users to choose different speeds as needed. ④ Charging function: The neckband fan can be charged via USB interface, using a power bank or computer. ⑤ 360-degree rotation: The neckband fan can be designed with adjustable airflow, allowing the fan angle to be freely rotated to meet individual needs. The main features of a neckband fan include: ① Comfortable wearing: It can be made of soft materials or have a lightweight design, ensuring that it will not cause burden or discomfort when worn. ② Quiet Design: The optimized motor and fan design of this neck fan reduces noise, making it suitable for use in quiet environments such as offices or libraries. ③ Multiple Styles: This neck fan comes in a variety of styles and colors to match different outfits and occasions. ④ High Safety: This neck fan features a bladeless design, preventing injury from finger contact with fan blades. ⑤ Long Battery Life: The neck fan is equipped with a long battery life, supporting several hours of continuous use to meet most daily needs. Therefore, this type of neck fan is particularly suitable for use in hot weather, especially during outdoor activities, fitness, and travel, effectively improving comfort.

[0251] The strap-on fan is a uniquely designed portable fan, typically used to secure itself to a specific location or be strapped to an object to provide circulating airflow or cooling. This type of fan is particularly suitable for certain special occasions, such as outdoor camping, cycling, or use in fixed work environments. The main functions of the strap-on fan include: ① Secure use: The fan can be fixed to chairs, tents, sheds, etc., using straps, clips, or other securing devices for extended use. ② Adjustable wind speed: This type of strap-on fan offers multiple wind speed settings, allowing users to select different settings according to their needs. ③ Versatile application: This type of strap-on fan is suitable for various scenarios such as outdoor activities, camping, sports, and home use. ④ Portable charging: This type of strap-on fan features a USB charging design for easy portability and charging. The main features of the strap-on fan include: ① Flexibility: The fan itself can be adjusted to different positions and angles, and the wind direction can be freely adjusted. ② Lightweight design: This type of strap-on fan is lightweight, easy to carry and install, and does not add much weight. ③ Durability: This strap-on fan is made of wear-resistant materials, suitable for outdoor environments, and can withstand a certain amount of wind and rain. ④ Quiet Operation: The silent design of this strap-on fan ensures minimal noise during use, making it suitable for quiet environments. ⑤ Multiple Styles: This strap-on fan is available in different colors and designs, allowing consumers to choose according to their personal preferences. Therefore, its flexibility and portability make it an ideal choice for many outdoor activities or fixed-location use.

[0252] The technical advantages of the above solution are as follows: On the one hand, by housing the fan assembly and noise reduction assembly within a portable casing, the physical size of the fan is greatly reduced, making the device easy to carry and suitable for use in various occasions, thus improving the portability and operability of the active noise-canceling fan. On the other hand, by differentiating itself from existing technologies, this solution, through the rational design of the noise reduction assembly's functions, can dynamically analyze various static noise signals, including intake noise, exhaust noise, fan blade noise, and / or motor noise. This allows for the real-time acquisition of dynamic comprehensive noise signals generated inside and outside the cavity during fan assembly operation. Based on these noise signals, a corresponding noise reduction signal with opposite phase, frequency, and amplitude is emitted, thereby canceling the noise signal and achieving active noise control of the fan assembly to reduce the noise level during fan operation.

[0253] Example 2

[0254] Please refer to Figures 1 to 13. The noise reduction component 300 includes a signal acquisition unit 310, a signal processor 320, and a signal generator 330. The signal acquisition unit 310 is disposed within the cavity 101 of the active noise-canceling fan 10 and is used to acquire noise signals generated by the active noise-canceling fan 10 in real time during operation. The signal processor 320 is disposed within the cavity 101 and electrically connected to the signal acquisition unit 310, and is used to call a pre-trained noise reduction model 240 to perform noise control processing on the noise signals to obtain noise control commands. The signal generator 330 is disposed within the cavity 101 and electrically connected to the signal processor 320, and is used to acquire the noise control commands and issue noise reduction signals according to the noise control commands to perform active noise control on the active noise-canceling fan 10.

[0255] In some embodiments, the active noise-canceling fan 10 is applied to a high-speed motor that operates at a speed exceeding a preset speed; wherein the high-speed motor includes a high-speed three-phase motor.

[0256] Specifically, the active noise-canceling fan 10 can be used with a high-speed motor operating at a speed exceeding a preset speed (e.g., above 12,000 rpm). Such high-speed motors tend to generate high noise during actual operation, thus requiring active noise reduction control via the active noise-canceling fan 10. In some preferred embodiments, the high-speed motor can be a high-speed three-phase motor, which can provide sufficient power and speed to ensure adequate airflow from the active noise-canceling fan 10. Furthermore, to ensure good overall vibration damping while using a high-speed three-phase motor, a buffer can be installed on the inner wall of the housing 100. This buffer can absorb and reduce vibrations from the high-speed three-phase motor, allowing the portable active noise-canceling fan 10 to rotate continuously and stably at high speed.

[0257] In one embodiment, the motor 210 is a three-phase high-speed motor, and the motor 210 also includes a drive plate. A fixing hole is provided inside the fan housing 120, and the drive plate is provided with a fixing opening. A fixing member passes through the fixing opening and is fixed to the fixing hole, thereby fixing the drive plate to the fan housing 120.

[0258] In one embodiment, when the fan assembly 200 is running, it generates noise signals inside and outside the cavity 101. The noise signals are dynamic composite noise signals that include intake noise, exhaust noise, fan blade noise, and / or motor noise.

[0259] Among them, the intake noise and exhaust noise are the noise signals generated by the housing 100 of the active noise reduction fan 10 when the air is intake and exhaust, respectively, and the fan blade noise and motor noise are the noise signals generated by the fan blade 220 and motor 210 of the active noise reduction fan 10 when they are running.

[0260] In some embodiments, the signal acquisition unit 310 can acquire dynamic composite noise signals inside and outside the cavity 101 in real time in response to the operation of the active noise-canceling fan 10.

[0261] Specifically, during the operation of the active noise-canceling fan 10, the air inlet and air inlet cover of its housing 100 will draw in a large amount of air, resulting in a corresponding amount of intake noise on the outer contour of the air inlet and air inlet. Alternatively, during the operation of the active noise-canceling fan 10, the air outlet 103 and air outlet cover of the housing 100 will also expel a large amount of air, resulting in a corresponding amount of exhaust noise on the outer contour of the air outlet 103. Alternatively, during the operation of the active noise-canceling fan 10, the rotation of the fan blades 220 will interact with the air, generating pressure pulsations and thus producing a corresponding amount of fan blade noise. Alternatively, during the operation of the active noise-canceling fan 10, when the rotor of the motor 210 cuts the magnetic lines of force, friction between the rotor and stator will generate a corresponding amount of motor noise. Therefore, the above four main static noise signals will dynamically combine into a comprehensive noise signal and be transmitted to the user's hearing system during the use of the active noise-canceling fan 10 (e.g., when the user is walking, running, or remaining stationary while holding the active noise-canceling fan 10). In some embodiments, the signal acquisition device 310 follows the user's usage scenario, collects in real time the comprehensive noise signal dynamically composed of the above-mentioned air intake noise, air outlet noise, fan blade noise and / or motor noise, and sends it to the signal processor 320 for detailed analysis and processing.

[0262] In some embodiments, the intake noise in the dynamic composite noise signal includes the static intake noise generated by the active noise-canceling fan 10 when it is used in a fixed position and the dynamic intake noise generated when the user shakes the fan; the exhaust noise includes the static exhaust noise generated by the active noise-canceling fan 10 when it is used in a fixed position and the dynamic exhaust noise generated when the user shakes the fan; the fan blade noise includes the static fan blade noise generated by the active noise-canceling fan 10 when it is used in a fixed position and the dynamic fan blade noise generated when the user shakes the fan; and the motor noise includes the static motor noise generated by the active noise-canceling fan 10 when it is used in a fixed position and the dynamic fan blade noise generated when the user shakes the fan.

[0263] Specifically, in practical applications, the active noise-canceling fan 10 can have multiple usage states, and the corresponding dynamic composite noise signal generated in each usage state is different. For example, when a user places it on a desktop as a desktop fan, the active noise-canceling fan 10 is in a stationary state, and the corresponding dynamic composite noise signal generated is static noise. Or, when a user holds it in their hand and moves it at irregular speeds and directions, the active noise-canceling fan 10 is in an irregular operating state, and the corresponding dynamic composite noise signal generated is dynamic noise.

[0264] In one embodiment, continuing as shown in FIG1, a pre-trained noise reduction model 240 is pre-stored in the signal processor 320. The pre-trained noise reduction model 240 can perform phase inversion processing on the noise signal to obtain inverted signal data, and generate noise control instructions based on the inverted signal data.

[0265] The noise control command includes inverse signal data that is opposite in phase to the noise signal but has the same frequency and amplitude.

[0266] In some embodiments, the pre-trained noise reduction model 240 can determine the spectral range and magnitude of the noise signal by analyzing the Hanning window spectrum of the noise signal, and calculate the corresponding inverted signal data. Then, the noise reduction model 240 generates a noise control command based on the inverted signal data, so that when the inverted signal in the noise control command is superimposed on the noise signal, they will cancel each other out in the same frequency range, thereby achieving the effect of noise reduction or interference suppression.

[0267] In some embodiments, the noise reduction model 240 can be integrated into the computer chip 325 of the active noise-canceling fan 10 to have signal processing capabilities. The aforementioned computer chip 325 can be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it can also be a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), an embedded ARM, or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. The general-purpose processor can be a microprocessor; the computer chip can also be any conventional processor, etc., and is not specifically limited in this application.

[0268] In one embodiment, the signal generator 330 can issue a noise reduction signal based on a noise control command to perform active noise control on the active noise-reducing fan 10.

[0269] Within a preset error tolerance range, the noise reduction signal and the noise signal are out of phase but have the same frequency and amplitude. This is used to perform destructive interference on the noise signal, thereby achieving active noise control of the fan.

[0270] Specifically, sound is composed of a certain spectrum. The spectrum of the noise reduction signal is exactly the same as the noise signal to be eliminated, but the phase is exactly opposite. That is, a phase difference of 180° can completely cancel out the noise signal. In this way, after the noise reduction signal interferes with and interferes with the sound, the new sound wave generated can be so weak that it is inaudible to the human ear, thereby reducing the impact of motor noise on humans.

[0271] It should be understood that signal acquisition equipment or environmental noise measurement may be affected by external factors, such as background noise and temperature changes, which may lead to inaccurate signal acquisition. Different noise reduction algorithms have their applicable ranges and limitations, and some algorithms may not be able to effectively handle noise in all frequency ranges, resulting in inaccurate noise reduction signal generation. Alternatively, the structure around the fan (such as walls, the ground, and other objects) may affect the propagation characteristics of sound waves, producing reflection, diffraction, or resonance, thereby changing the signal acquisition effect. Ultimately, this may result in the generated noise reduction signal not being completely 180° out of phase with the noise signal, and / or not having the same frequency and amplitude. Therefore, a preset error allowable range can be set. As long as the generated noise reduction signal and the noise signal are within this error allowable range, they are considered to be out of phase and have the same frequency and amplitude.

[0272] The technical advantages of the above solution are as follows: On the one hand, by using a pre-trained noise reduction model to process the noise signal and obtain a noise control command, the noise control command is then used to actively control the noise of the portable fan, thereby optimizing the noise reduction process of the portable fan, reducing the complexity of executing the active noise reduction program, and reducing labor costs. On the other hand, by using a method different from existing technologies and through the reasonable design of the signal generator, a noise reduction signal with the opposite phase, frequency, and amplitude to the noise signal can be emitted within a preset error allowable range, thereby canceling the noise signal and realizing active noise control of the portable fan to reduce the noise level during fan operation.

[0273] Those skilled in the art will understand that the disclosed methods in the specific embodiments described above can be implemented in more specific ways. For example, the portable fan performs noise control processing on the noise signal based on a pre-trained noise reduction model to obtain noise control commands, etc., which is merely one set of methods; in actual implementation...

[0274] There can be other ways of classifying them. For example, the noise generated by a portable fan during operation, including intake noise, exhaust noise, fan blade noise, and motor noise, can be combined or integrated into another system, or some features can be ignored or not executed.

[0275] In one embodiment, referring to Figure 13, the noise reduction model 240 includes a pre-trained classification network 241 and a noise reduction signal database 242. The classification network 241 is connected to the signal acquisition unit 310 and is used to classify the acquired noise signals to determine the noise scene category in which the active noise-reducing fan 10 is located. The noise reduction signal database 242 is connected to the classification network 241 and is used to perform signal matching processing on the noise signals based on the noise scene category, determine the target noise reduction signal that matches the noise signal, and generate noise control instructions based on the target noise reduction signal.

[0276] Specifically, the pre-trained noise reduction model 240 pre-stores multiple trained classification networks 241. Each classification network 241 can correspond to multiple noise scene categories, including train stations, subway cars, and buses, as well as specific environmental noises such as vehicle processing plants and machinery manufacturing plants. This application does not impose any specific limitations on these categories. Thus, based on the noise scene category, the noise reduction model 240 can access / call the stored classification network 241 corresponding to that noise scene category and applicable to that noise scene category.

[0277] In other embodiments, the noise scene category may also be related to the user's actual usage state of the active noise-canceling fan 10, and the corresponding noise scene category may differ in each usage state. For example, when the user places it on a desktop as a desktop fan, the portable fan is in a stationary state, and its corresponding noise scene category is static noise scene; or when the user holds it and moves it at irregular speeds and directions, the portable fan is in an irregular operating state, and its corresponding noise scene category is dynamic noise scene.

[0278] In some embodiments, the classification network 241 can utilize various classification algorithms to classify noise scene categories, such as, but not limited to, logistic regression, Gaussian mixture model-based classification, hidden Markov model-based classification, and any of the classification neural networks. To improve the accuracy of the classification algorithm and reduce the computational complexity, the classification network 241 can also enable the active noise-canceling fan 10 to communicate with smart devices to obtain its current location from its GPS unit, such as, but not limited to, train stations, tunnels, subway cars, theaters, etc., thereby enabling the classification of noise scenes based on the current location. Among these classification algorithms, the classification neural network, for example, can be pre-trained using a set of training samples composed of speech signals from various noise scenes. The trained classification neural network can also be stored on the noise reduction model 240 for the active noise-canceling fan 10 to access at any time.

[0279] In some embodiments, each noise scene category corresponds to a noise reduction signal database 242, and each noise reduction signal database 242 is used to store noise reduction signals that are opposite in phase but have the same frequency and amplitude as a variety of preset noise signals.

[0280] Understandably, the noise reduction model 240 can use the classification network 241 to classify the received noise signal, and then, based on the determined category of the noise scene, call the noise reduction signal database 242 to determine the target noise reduction signal that matches the noise signal, and generate a noise control command based on the target noise reduction signal, thereby using the noise control command to realize the noise reduction processing of the noise signal and provide the user with a noise-reduced audio signal.

[0281] For example, when a user holds the active noise-canceling fan 10 in their hand and moves it at irregular speeds and directions, most of the noise is caused by noise signals generated when air flows through the cavity. The active noise-canceling fan 10 in this noise scenario receives noise signals containing the air inlet 102, the air outlet 103, and the center of the air duct. At this time, the noise reduction model 240 calls the pre-stored classification network 241 corresponding to the noise scenario to determine its noise scenario category, and then calls the corresponding noise reduction database 242 based on the classification network 241 to perform noise reduction processing on the audio signal containing noise.

[0282] In some embodiments, the noise reduction model 240 is further configured to determine whether the noise scene category has changed based on the input noise signal, and if the noise scene category has changed, to call the stored noise reduction signal database 242 corresponding to the changed noise scene category to generate a new noise control instruction.

[0283] It is understandable that when a user uses the active noise-canceling fan 10, the noise environment in which the noise signal is generated will frequently change. For example, when a user is in a subway station, the noise environment in which they are in is generated by broadcasts and human voices, and this noise environment is the first noise environment. When a user enters a subway car from the subway station, the noise environment in which they are in is generated by the movement of the train, and this noise environment is the second noise environment. It can be seen that the noise reduction model 240 can perform noise reduction processing using the corresponding classification network 241 in the first noise environment. When the user changes from the first noise environment to the second noise environment, the change in the noise environment category can be determined based on the confirmation result of the classification of the received noise signal, and the corresponding classification network 241 corresponding to the changed noise environment category, that is, the second noise environment category, can be called for noise reduction processing. In this way, noise signals can be denoised in real time when the noise scene category changes, and the denoising process of the current classification network 241 can be continuously used even when the noise scene category does not change. This saves the computational resources of the denoising model and improves the computational speed while continuously denoising. It also avoids the denoising model from calling the stored classification network 241 again when it is confirmed that the noise scene category has not changed.

[0284] In some embodiments, the classification network 241 includes a Long Short-Term Memory (LSTM) network or a Gated Recurrent Unit (GRU) with a depth of less than 4 layers. LSTM is a type of Recurrent Neural Network (RNN). LSTM uses a gating mechanism to enable the recurrent neural network to not only remember past information but also selectively forget some less important information to model long-term contextual relationships. GRU is based on this idea to reduce the gradient vanishing problem while preserving long-term sequence information. Furthermore, since a smaller depth and fewer layers in the classification network 241 result in faster computation, a depth of less than 4 layers effectively ensures the speed of noise reduction processing.

[0285] In some embodiments, the classification network 241 corresponding to each noise scene is pre-trained on the denoising model 240, and the pre-training is performed based on training sample sets of different noise scene categories. The training samples of each noise scene category include noisy signals and noise-free signals of the corresponding noise scene category.

[0286] Example 3

[0287] Please refer to Figures 14 to 16. The active noise-canceling fan 10 has a motor 210 and a motor noise reduction device 50 disposed inside the fan housing 120. The motor noise reduction device 50 includes a noise collector 510, a noise processor 520, and a noise suppressor 530. The noise collector 510 is disposed inside the fan housing 120 and is used to collect the motor noise generated by the active noise-canceling fan 10 in real time during operation. The motor noise includes the mechanical vibration noise, electromagnetic noise, and aerodynamic noise of the motor 210. The noise processor 520 is disposed inside the fan housing 110 and electrically connected to the noise collector 510. It is used to generate a noise control command based on the motor noise when the noise intensity of the noise signal is greater than the intensity threshold. The noise suppressor 530 is disposed inside the fan housing 120 and electrically connected to the noise processor 520. It is used to acquire the noise control command and issue a noise reduction signal according to the noise control command to cancel the motor noise.

[0288] In one embodiment, when the active noise-canceling fan 10 is running, the motor 210 generates motor noise inside and outside the cavity 101, and this motor noise propagates in the form of an audio signal. Among the motor noise, the motor noise generated by the motor 210 during operation, such as mechanical vibration noise, electromagnetic noise, and aerodynamic noise, is the main source of fan noise.

[0289] Specifically, mechanical vibration noise is the sound generated by the vibration of internal mechanical components of a motor during relative motion due to friction, collision, imbalance, or structural resonance, which is transmitted into the air through the motor's connecting parts. Electromagnetic noise is the sound generated when the electromagnetic force (attraction or repulsion) between the stator and rotor of a motor fluctuates periodically due to changes in the magnetic field during operation, causing vibrations in the core, casing, and other structures, which are then transmitted through the air. Its core is the "periodic change of electromagnetic interaction." Aerodynamic noise is the sound generated when the internal or external air is disturbed during motor operation (such as airflow cutting, turbulence, or pressure changes). Its core is the "vibration of air particles." For example, when the motor rotor rotates, it drives the internal air (such as the air in the gap between the stator and rotor) to flow. If the gap is uneven or there are protruding structures (such as the ends of coils), it will cause air turbulence, generating high-frequency airflow noise.

[0290] In some embodiments, the noise collector 510 can collect motor noise signals in the cavity 101 in real time in response to the operation of the motor 210.

[0291] Specifically, the noise collector 510 is located inside the fan housing 120 and may include multiple microphone arrays and multiple vibration sensors. The microphone arrays are distributed at a preset angle around the motor 210 to collect motor noise signals propagating through the air; the vibration sensors are fixed to the motor bearing housing and stator housing with thermally conductive adhesive to monitor mechanical vibration data in real time. In some embodiments, the noise collector 510 collects the motor noise generated by the motor 210 during operation in real time, including mechanical vibration noise, electromagnetic noise, and aerodynamic noise, and sends it to the noise processor 520 for detailed analysis and processing.

[0292] In some embodiments, a noise processor 520 is disposed on the hand housing 110. A pre-trained noise reduction model is pre-stored in the noise processor 520. The pre-trained noise reduction model can perform phase inversion processing on various motor noise signals to obtain inverted signal data, and generate corresponding noise control commands based on various inverted signal data.

[0293] The noise control command includes inverse signal data that is opposite in phase to the motor noise signal but has the same frequency and amplitude.

[0294] In some embodiments, the pre-trained noise reduction model can determine the spectral range and magnitude of the motor noise signal by analyzing the Hanning window spectrum of the motor noise signal, and calculate the corresponding inverted signal data. Then, the noise reduction model generates noise control commands based on the inverted signal data. When the inverted signal in the noise control command is superimposed on the motor noise signal, they will cancel each other out within the same frequency range, thereby achieving the effect of noise reduction or interference suppression.

[0295] In one embodiment, the noise suppressor 530 is integrated into the fan housing 120 and can receive noise control commands for mechanical vibration noise, electromagnetic noise and aerodynamic noise respectively, and issue corresponding noise reduction signals based on various noise control commands to perform active noise control on the active noise reduction fan 10.

[0296] Within a preset error tolerance range, each noise reduction signal has the opposite phase and the same frequency and amplitude as its corresponding motor noise signal. This is used to perform destructive interference on mechanical vibration noise, electromagnetic noise, and aerodynamic noise, respectively, in order to achieve active noise control of the motor 210.

[0297] Specifically, sound is composed of a certain spectrum. The spectrum of the noise reduction signal is exactly the same as the noise signal to be eliminated, but the phase is exactly opposite. That is, a phase difference of 180° can completely cancel out the noise signal. In this way, after the noise reduction signal interferes with and interferes with the sound, the new sound wave generated can be so weak that it is inaudible to the human ear, thereby reducing the impact of motor noise on humans.

[0298] It should be understood that the noise acquisition unit 510 or the environmental noise measurement may be affected by external factors, such as background noise and temperature changes, which may lead to inaccurate signal acquisition. Different noise reduction algorithms have their applicable range and limitations. Some algorithms may not be able to effectively handle noise in all frequency ranges, resulting in inaccurate noise reduction frequency generation. Alternatively, the structure around the fan (such as walls, the ground, and other objects) may affect the propagation characteristics of sound waves, producing reflection, diffraction, or resonance, thereby changing the signal acquisition effect. Ultimately, this may result in the generated noise reduction signal not being completely out of phase (180°) with the motor noise signal, and / or not having the same frequency and amplitude. Therefore, a preset error allowable range can be set. As long as the generated noise reduction signal and the noise signal are within this error allowable range, they are considered to be out of phase and have the same frequency and amplitude.

[0299] In other embodiments, the three main motor noise signals described above will dynamically combine into a comprehensive noise signal and be transmitted to the user's hearing system during the use of the active noise-canceling fan 10 (e.g., when the user is walking, running, or standing still while holding the active noise-canceling fan 10). In some embodiments, the noise collector 510 follows the user's usage scenario, collects the comprehensive noise signal dynamically composed of the aforementioned mechanical vibration noise, electromagnetic noise, and aerodynamic noise in real time, and sends it to the noise processor 520 for detailed analysis and processing.

[0300] Specifically, in practical applications, the active noise-canceling fan 10 can have multiple usage states, and the corresponding dynamic composite noise signal generated in each usage state is different. For example, when a user places it on a desktop as a desktop fan, the active noise-canceling fan 10 is in a stationary state, and the corresponding dynamic composite noise signal generated is static noise. Or, when a user holds it in their hand and moves it at irregular speeds and directions, the active noise-canceling fan 10 is in an irregular operating state, and the corresponding dynamic composite noise signal generated is dynamic noise.

[0301] The technical effects of the above solution are as follows: On the one hand, through the linkage mechanism of noise acquisition, processing and suppression, it can accurately reduce various noises generated by the handheld fan drive motor, thereby improving the user's comfort and experience when using the handheld fan; on the other hand, by combining a noise processor with noise control commands generated based on preset thresholds and algorithms, and then using a noise suppressor to emit noise reduction signals for destructive interference, it can achieve active noise reduction and accurate processing of the noise of the handheld fan drive motor, thereby reducing the noise level generated by the motor during operation.

[0302] In one embodiment, as shown in FIG17, the fan assembly 200 disposed inside the air supply section 110 includes a hub 221 and a plurality of blades 222 spaced apart on the outer surface of the hub 221; wherein, the hub 221 includes a conical cavity 2211, which is used to cover and fix the motor 210.

[0303] In some embodiments, the hub 221 includes a guide surface that increases radially from rear to front, and a rotating shaft fixed at the center of the inner side of the hub 221. The stator assembly 211 and rotor assembly 212 of the motor 210 are both housed within the conical cavity 2211 of the hub 221. Further, the hub 221 includes an annular extension wall, within which both the stator assembly 211 and rotor assembly 212 are housed. The stator assembly 211 is sleeved outside the sleeve of the circuit board 213, and includes coils. The rotor assembly 212 is radially disposed between the stator assembly 211 and the hub 22121. The rotating shaft at the center of the hub 221 is inserted into the sleeve, and the extension wall, stator assembly 211, and rotor assembly 212 extend forward into the clearance space.

[0304] In one embodiment, the noise collector 510 includes at least one microphone; wherein the at least one microphone is disposed at at least one target point within the cavity 101 to collect motor noise signals near each target point in real time.

[0305] In some embodiments, as shown in FIG18, the noise collector 510 includes a first microphone 511, a second microphone 512, and a third microphone 513. The first microphone 511 is disposed on the inner wall (i.e., the annular extension wall) of the conical cavity 2211 and is used to collect electromagnetic noise generated by the motor 210 during operation. The second microphone 512 is disposed on the outer surface of the hub 221 and is used to collect aerodynamic noise generated by the motor 210 during operation. The third microphone 513 is disposed on the circuit board 213 of the motor 210 and is used to collect mechanical vibration noise generated by the motor 210 during operation.

[0306] Specifically, the first pickup 511 senses the electromagnetic radiation of the motor windings and converts the magnetic field change into a voltage signal; the second pickup 512 captures the sound wave pressure change generated by the interaction between the blade 142 and the air; and the third pickup 513 converts the mechanical vibration of the circuit board 213 into an electrical signal. These three signals are preprocessed and then synchronously transmitted to the noise processor 520.

[0307] In an exemplary embodiment, the noise collector 510 is located inside the fan housing 120 and employs a distributed multi-source acquisition architecture. Specifically, it includes: a first microphone 511, which uses a miniature electromagnetic induction sensor (such as the T942-10 type), is located on the inner wall (annular extended wall) of the conical cavity 2211 and is connected to the noise processor 520 via a magnetically shielded cable. Its sensing end is close to the stator winding of the motor 210 and is used to collect electromagnetic noise in the 100-5000Hz frequency band, especially the pulse electromagnetic radiation generated by the motor commutation. The second microphone 512 uses a MEMS microphone array (sensitivity -42dBFS, frequency response 20-20000Hz), located on the outer surface of the hub 221 near the root of the blade 142, and is fixed by a silicone vibration damping seat. Its pickup direction is towards the fan blade rotation surface and is used to collect turbulence noise and eddy current noise generated by air flowing through the fan blade. The third pickup 513 is a piezoelectric vibration sensor (range ±5g, resonant frequency 10kHz), which is attached to the circuit board 213 of the motor 210 (i.e., the power drive module area) with thermally conductive adhesive. It is used to collect mechanical vibration noise generated by motor bearing friction and rotor imbalance, with a sampling frequency of up to 44.1kHz.

[0308] In some embodiments, since the noise of the fan assembly 200 is mainly generated when the fan assembly 200 rotates, in one possible implementation, the second microphone 512 is disposed on the outer surface of the hub 221 of the fan assembly 200 and is configured to collect the aerodynamic noise generated during the operation of the hub.

[0309] In this way, the second pickup 512 can transmit the aerodynamic noise to the noise processor 520 to extract the amplitude, frequency and phase characteristics of the noise signal, and generate a noise reduction signal to cancel the noise signal through the noise suppressor 530, thereby partially or completely eliminating the aerodynamic noise generated by the blades of the fan assembly 200 when rotating.

[0310] Furthermore, in addition to the large noise generated by the hub 221 and blades 142 of the fan assembly 200 when rotating with the motor 210, the rotor assembly 212 of the motor 210 also generates noise signals when cutting magnetic lines of force, and the friction between the rotor assembly 212 and the stator assembly 211. In some embodiments, the noise collector 510 also includes a first pickup 511 and a third pickup 513. The first pickup 511 is disposed on the inner wall of the conical cavity 2211, and the third pickup 513 is disposed on the circuit board 213, and is configured to collect the electromagnetic noise and mechanical vibration noise of the motor 210, respectively.

[0311] Thus, the first pickup 511 can transmit the electromagnetic noise to the noise processor 520, and the second pickup 213 can transmit the mechanical vibration noise to the noise processor 520, so as to extract the amplitude, frequency and phase characteristics of the noise signal respectively, and generate a noise reduction signal to cancel the noise signal using the noise suppressor 530 based on these characteristics, thereby partially or completely eliminating the electromagnetic noise generated by the motor 210 during operation.

[0312] In other embodiments, although the related technology reduces the noise generated when air flows in the cavity 101 by improving the structure of the air casing, some noise is still inevitably generated when air flows in the cavity 101. Therefore, in some embodiments, the noise collector 510 also includes a fourth microphone, which is respectively disposed on the inner wall near the air inlet 102, the air outlet 103 and the center of the air duct in the cavity 101, and is configured to collect noise signals from the air inlet 102, the air outlet 103 and the center of the air duct.

[0313] Thus, the fourth microphone can collect the noise signal generated when air flows in the cavity 101 and transmit the noise signal to the noise processor 520 to extract the amplitude, frequency and phase characteristics of the noise signal. Based on these characteristics, the noise suppressor 530 generates a noise reduction signal to cancel the noise signal, thereby eliminating the noise signal generated in the air inlet 102, air outlet 103 and air duct center 104 in the cavity 101 when the fan assembly 200 is running.

[0314] In one embodiment, as shown in FIG19, the noise processor 520 includes a first processing submodule 521, a first determining submodule 522, a second determining submodule 523, and a first generating submodule 524. The first processing submodule 521 is used to perform framing, windowing, and time-frequency transformation processing on mechanical vibration noise, electromagnetic noise, and aerodynamic noise respectively, to obtain multiple corresponding frequency domain noise frames. The first determining submodule 522 is used to determine the noise suppression frame corresponding to each motor noise, with multiple noise suppression frames corresponding one-to-one with multiple frequency domain noise frames, and the corresponding noise suppression frames and frequency domain noise frames having opposite phases and the same amplitude and frequency. The second determining submodule 523 is used to determine the compensation gain corresponding to each frequency within a target frequency range based on the motor speed and vibration frequency of the motor 210, the airflow speed of the fan casing 120, and the number of fan blades. This target frequency range is the frequency range in which each motor noise is located. The first generating submodule 524 is used to generate noise control commands for mechanical vibration noise, electromagnetic noise, and aerodynamic noise based on each noise suppression frame and the compensation gain corresponding to each frequency within the target frequency range.

[0315] In one exemplary embodiment, a noise processor 520 is disposed on the hand housing 110, employs a dual-core DSP chip (such as ADI ADSP-BF707), integrates four functional sub-modules, and realizes real-time signal processing (total delay ≤10ms) through a hardware acceleration unit.

[0316] In some embodiments, the first processing submodule 521 performs signal preprocessing on the mechanical vibration noise collected by the third pickup 513, the electromagnetic noise collected by the first pickup 511, and the aerodynamic noise collected by the second pickup 512, respectively. This includes: performing frame segmentation with a frame length of 20ms and an overlap rate of 50% to balance time resolution and frequency resolution; applying a Hanning window to the mechanical vibration noise (to reduce spectral leakage), a rectangular window to the electromagnetic noise (to preserve pulse characteristics), and a Blackman window to the aerodynamic noise (to improve high-frequency resolution); and converting the time-domain signal to the frequency domain through a fast Fourier transform (FFT, 1024 points) to obtain multiple frequency-domain noise frames corresponding to the noise (frequency resolution ≤ 20Hz).

[0317] In some embodiments, the first determining submodule 223 generates a corresponding noise suppression frame based on the phase, amplitude, and frequency parameters of the frequency domain noise frame; then, it performs phase reversal (Δφ = π) on each frequency domain noise frame to ensure destructive interference with the original noise; then, it uses automatic gain control (AGC) to make the amplitude of the noise suppression frame consistent with that of the frequency domain noise frame (error ≤ 3%); finally, it uses phase-locked loop (PLL) technology to keep the frequency of the noise suppression frame synchronized with that of the frequency domain noise frame (drift ≤ 0.1Hz) to ultimately form a noise suppression frame sequence that corresponds one-to-one with the frequency domain noise frame.

[0318] In some embodiments, the second determining submodule 523 constructs a dynamic compensation model, which calculates the compensation gain within the target frequency range based on multi-parameter fusion. Specifically, this includes: inputting the real-time rotational speed of the drive motor (collected by a Hall sensor, range 2000-6000 rpm), vibration frequency (extracted from the signal of the third microphone), airflow speed of the air supply section (converted from the impeller speed, range 3-8 m / s), number of fan blades (preset parameter, such as 6 blades), and the target frequency range, such as mechanical vibration noise (500-3000 Hz), electromagnetic noise (1000-5000 Hz), and aerodynamic noise (800-8000 Hz); then using a piecewise function for dynamic adjustment, for example: when the motor speed is >4000 rpm, the aerodynamic noise compensation gain is increased by 1.2 times; when the vibration frequency is in the resonant frequency band (1800-2200 Hz), the mechanical vibration noise compensation gain is increased to 1.5 times; finally, the electromagnetic noise compensation gain is positively correlated with the current intensity.

[0319] In some embodiments, the first generation submodule 524 integrates the noise suppression frame and the compensation gain to generate dedicated control commands for three types of noise. Specifically, the noise suppression frame is multiplied by the compensation gain and converted into a PWM control signal (frequency 1-10kHz). Then, the processed suppression frame is subjected to D / A conversion to generate an analog voltage signal (0-3.3V). Finally, an audio drive signal (power ≤0.5W) is generated through a digital-to-analog converter to transmit all commands to the noise suppressor 530 via the SPI bus, ensuring real-time performance.

[0320] In other embodiments, the first processing submodule 521 may also use an analog-to-digital converter to perform analog-to-digital conversion processing on the motor noise signals of each frame to obtain the corresponding pulse code signals; then, the pulse code signals of each frame are input into the first determining submodule 522 to perform phase inversion processing to obtain the noise suppression frames corresponding to each motor noise.

[0321] In one embodiment, the noise suppressor 530 includes at least one sound player 331 and a power amplifier 332 disposed at each target point;

[0322] Among them, the power amplifier 332 is used to acquire noise control commands for mechanical vibration noise, electromagnetic noise and aerodynamic noise respectively, and amplify the noise reduction data carried by various noise control commands to obtain the corresponding power amplification signal.

[0323] Specifically, the power amplifier 332 includes a power amplifier circuit, which includes a signal input terminal and a signal output terminal. The signal input terminal of the power amplifier circuit is electrically connected to the first generation submodule 524. The first generation submodule 524 includes multiple signal output ports for outputting generated noise control commands. The signal input terminal of the power amplifier circuit is electrically connected to the signal output ports of the first generation submodule 524. The signal output terminal of the power amplifier circuit is electrically connected to the sound player 331. The power amplifier circuit is used to amplify the noise reduction data generated by the first generation submodule 524.

[0324] Among them, the sound player 331 is used to emit noise reduction signals that are opposite in phase and have the same frequency and amplitude as various motor noises, according to the power amplification signal.

[0325] Specifically, after the first generation submodule 524 generates the noise reduction data, it needs to be played out through the sound player 331 so that the noise reduction signal interferes with or interferes with the noise signal, thereby canceling out part or all of the noise signal.

[0326] In some embodiments, the noise suppressor 530 performs digital-to-analog conversion and signal amplification on the noise-reduced signal data input from the first generation submodule 524 and outputs it to the sound player 331. This noise-reduced signal data is mainly used to suppress noise signals from the original environment; this process is called active noise reduction.

[0327] Therefore, the noise suppressor 530 may include multiple sound players 331, each sound player 331 and the microphone are in a one-to-one correspondence in position, so that the noise reduction signal played by different sound players 331 can eliminate the corresponding noise signal.

[0328] In one embodiment, as shown in FIG18, the sound player 331 includes: a first player 3311 disposed on the inner wall of the conical cavity 2211 and corresponding to the first microphone 511, used to acquire a power amplified signal for electromagnetic noise to play a first noise reduction signal; a second player 3312 disposed on the outer surface of the hub 221 and corresponding to the second microphone 512, used to acquire a power amplified signal for aerodynamic noise to play a second noise reduction signal; and a third player 3313 disposed on the circuit board 213 of the motor 210 and corresponding to the third microphone 513, used to acquire a power amplified signal for mechanical vibration noise to play a third noise reduction signal.

[0329] Specifically, the noise suppressor 530 is located inside the fan housing 120, and its core component is the sound player 331, which adopts a distributed layout to form a one-to-one correspondence with the noise collector 510. Specifically, the first player 3311 receives electromagnetic noise control commands and generates a reverse electromagnetic field through an electromagnetic speaker, creating destructive interference with the electromagnetic noise of the motor 210 in the stator winding region; the second player 3312 receives aerodynamic noise control commands and emits anti-phase sound waves through a MEMS speaker, creating acoustic interference in the airflow generated by the fan blade rotation to cancel turbulence noise; the third player 3313 receives mechanical vibration noise control commands and generates anti-phase vibration through a piezoelectric vibrator, which is transmitted to the motor housing via the circuit board 213 to cancel mechanical vibration transmission. The spatial matching degree between these three types of noise reduction signals and their corresponding noise sources is over 90%, ensuring maximum interference effect.

[0330] Since the noise of the fan assembly 200 is mainly generated when the fan assembly 200 rotates, in one possible implementation, the second player 3312 is disposed on the hub 221 of the fan assembly 200 and is configured to play an inverse noise-reducing signal to the rotating blades 142.

[0331] In this way, the second player 3312 can play an inverse noise reduction signal to the operating blades according to the noise control command issued by the first generation submodule 524, so as to cancel the noise signal generated in the target area, thereby partially or completely eliminating the noise generated by the blades 142 of the fan assembly 200 when rotating.

[0332] Furthermore, in addition to the significant noise generated by the hub 221 and blades 142 during rotation, noise signals are also generated by the rotor assembly 212 of the motor 210 cutting magnetic lines of force and by friction between the rotor assembly 212 and the stator assembly 211. In some embodiments, a first player 3311 is disposed on the inner wall of the conical cavity 2211, and a third player 3313 is disposed on the circuit board 213 and configured to play an inverse noise-reducing signal to the operating motor 210.

[0333] Thus, the first player 3311 and the third player 3313 can play an inverse noise reduction signal to the running motor 210 according to the noise control command issued by the first generation submodule 524, so as to cancel the noise signal generated in the target area, thereby partially or completely eliminating the noise generated by the motor 210 of the fan assembly 200 during operation.

[0334] In other embodiments, although the related technology reduces the noise generated when air flows in the cavity 101 by improving the structure of the fan shell, some noise is still inevitably generated when air flows in the cavity 101. Therefore, in some embodiments, the multiple sound players 331 also include a fourth speaker, which is respectively disposed on the inner wall near the air inlet 102, air outlet 103 and air duct center 104 in the cavity 101, and is configured to play an inverse noise-reducing signal to the target area near the air inlet 102, air outlet 103 and air duct center 104.

[0335] Thus, the fourth speaker can play inverse noise reduction signals to the target area near the air inlet 102, air outlet 103 and air duct center respectively according to the noise control command issued by the first generation submodule 524, so as to cancel the noise signal generated in the target area, thereby eliminating the noise generated in the air inlet 102, air outlet 103 and air duct center in the cavity 101 when the fan assembly 200 is running.

[0336] In other embodiments, the sound player 331 for each target area may also include a plurality of noise-canceling speakers, and at least two of the noise-canceling speakers are oriented differently.

[0337] In other words, when collecting noise signals, multiple noise collectors 510 will collect noise signals from different parts of the fan assembly 200. In order to specifically cancel different noise signals, different cancellation sound wave signals need to be generated and played according to the propagation direction of different noise signals. Therefore, during playback, the propagation direction of the noise reduction signal for different noise signals will also be different. Thus, the sound playback direction of multiple noise reduction speakers is different to eliminate noise signals propagating from various directions.

[0338] In some implementations, the number of noise-canceling speakers can be an even number, with multiple noise-canceling speakers arranged in a circle, and the orientations of two opposing noise-canceling speakers facing away from each other.

[0339] For example, the number of noise-canceling speakers can be four or six. When there are four noise-canceling speakers, adjacent speakers are arranged at a 90-degree angle, and all speakers face outwards. When there are six noise-canceling speakers, adjacent speakers are arranged at a 60-degree angle, and opposite speakers face back to back. In this way, multiple noise-canceling speakers can play noise-canceling wave signals in all directions to better eliminate noise.

[0340] In one exemplary embodiment, the first player 3311 is a miniature electromagnetic loudspeaker (6mm in diameter, 2mm thick), disposed on the inner wall of the conical cavity 2211 and symmetrically distributed 180° with the first pickup 511 (electromagnetic noise acquisition end). Its diaphragm faces the stator winding of the motor 210, and it incorporates neodymium iron boron magnets to enhance the magnetic field response, with a frequency response range of 1000-5000Hz (covering the main frequency band of electromagnetic noise). It is connected to a power amplifier circuit via a 10mm long shielded cable to receive a power amplification signal for electromagnetic noise and play a first noise reduction signal that is out of phase with the electromagnetic noise, so as to cancel electromagnetic radiation noise through electromagnetic field interference.

[0341] In one exemplary embodiment, the second player 3312 employs an ultra-thin MEMS speaker (8mm × 8mm in size, 1.2mm in thickness), positioned on the outer surface of the hub 221 near the center of the blade 142, maintaining a 30° angle with the second microphone 512 (aerodynamic noise acquisition end), with both pickup and playback directions pointing towards the plane of rotation of the blade 142. Its frequency response range is 800-8000Hz, and its sound pressure level is 90dB / kHz. It is fixed with a silicone vibration damping bracket to avoid interference from its own vibration. After receiving a power-amplified signal targeting aerodynamic noise, it plays a second noise-reducing signal (i.e., an anti-phase sound wave), forming an acoustic interference zone around the fan blades to cancel out turbulence and eddy current noise.

[0342] In one exemplary embodiment, the third player 2113 is a piezoelectric ceramic vibrator (5mm in diameter, 0.8mm thick), attached to the grounded copper foil area of ​​the circuit board 213, adjacent to the third microphone 513 (mechanical vibration noise acquisition end) (spacing ≤2mm). Its resonant frequency is 100-3000Hz, with a maximum amplitude of 5μm, and it is fixed with thermally conductive double-sided adhesive to combine vibration transmission and heat dissipation. After receiving a power-amplified signal targeting mechanical vibration noise, it generates a third noise-reducing signal (i.e., a mechanical vibration wave) with an opposite phase to the motor vibration, which is transmitted through the circuit board 213 to the motor housing, canceling out vibrations caused by bearing friction and rotor imbalance.

[0343] Example 4

[0344] Please refer to Figures 20 and 22. The hub 221 is constructed with an annular sidewall 2212, which is used to accommodate the high-speed three-phase micro motor 210 (not shown in the figure). The plurality of blades 222 include a blade root 2221 and a blade tip 2222. Each blade 222 is connected to the outer surface of the annular sidewall 2212 through the blade root 2221 and is arranged at intervals along its circumference.

[0345] Among them, each blade 222 has an arc-shaped protruding blade tip wing 2223 at the blade tip 2222. The blade tip wing 2223 is inclined at a preset angle to the axial direction of the hub 221, so as to reduce the aerodynamic noise generated by the airflow leakage at the blade tip 2222 when the high-speed three-phase micro motor 210 drives the fan blade 220 to rotate.

[0346] In this embodiment, as shown in FIG20, the hub 221 is constructed in a frustum shape. The hub 221 includes an end face and an annular sidewall 2212, and its end face can be constructed as (not limited to): a circular plane, a hemispherical shape, a conical surface, or a frustum shape. The end face and the annular sidewall 2212 are connected to form a complete hub 221.

[0347] In this embodiment, the fan blade 220 has 7 blades 222. However, the number of blades 222 is not limited to this. Depending on the specific application scenario, in some embodiments, the number of blades 222 can be (not limited to): 2, 3, 4, 5, 6, 8, 9, 10, 11, 13, 14 or more.

[0348] In some embodiments, the hub 221 and the blade 222 are integrally injection molded. Both the hub 221 and the blade 222 are made of glass fiber, with the glass fiber content being, for example, 28%-32%. Because the size of the fan blade 220 is much smaller than that of a large fan blade, a material with good flowability (such as ABS) can be used during injection molding to ensure filling. Adding 28%-32% glass fiber allows the fan blade 220 to maintain good strength, rigidity, and structural stability even during high-speed operation or long-term use. Of course, in other embodiments, the blade 222 can be made of other materials with added glass fiber, and this is not a limitation.

[0349] In some embodiments, the hub 221 is made of metal or high-strength engineering plastic, and has an annular sidewall 2212 in its middle. The central hole of the annular sidewall 2212 is used to fix the shaft of the high-speed three-phase micro motor 210 (not shown in the figure) by interference fit or by means of keyway or other means.

[0350] In some embodiments, a plurality of blades 222 are fixedly connected to the outer surface of the annular sidewall 2212 of the hub 221 via their blade roots 2221 and are evenly spaced along the circumference. The profile of the blades 222 can be airfoil or arc plate, which extends from the blade root 2221 in a direction away from the hub 221, and the end is the blade tip 2222.

[0351] In some embodiments, an arc-shaped protruding tip winglet 2223 is provided at the tip 2222 of each blade 222. The tip winglet 2223 can be integrally injection molded with the blade 222 body to ensure structural strength and stability.

[0352] As shown in Figures 21 and 22, the blade tip winglet 2223 does not extend vertically upwards, but forms a preset tilt angle θ with the axial direction of the hub 221 (i.e., the direction of the central axis of the motor shaft). The design of this tilt angle θ is crucial for guiding airflow. The arcuate protrusion direction of the blade tip winglet 2223 can be set to be the same as or opposite to the rotation direction D of the fan blade 220, depending on the specific flow field design requirements, to achieve optimal leakage flow blocking and guiding effects. Furthermore, it can protrude outwards from the suction surface A of the blade 222, or from the pressure surface B, or both simultaneously.

[0353] In one embodiment, the blade tip winglet 2223 is tilted outward at an angle of 10° to 30° relative to the axial direction of the hub 221. Within this 10° to 30° tilt angle range, the blade tip winglet 2223 can most effectively "catch" airflow attempting to leak laterally and guide it towards the main airflow direction, while simultaneously generating an additional vortex system to suppress leakage vortices, thereby optimizing aerodynamic performance.

[0354] In one embodiment, under high-speed rotation, the root of the blade tip winglet is subjected to enormous centrifugal force and aerodynamic load. Sharp corners can cause stress concentration, which can easily lead to material fatigue or even cracking. Therefore, a rounded transition with a radius of 3 mm to 7 mm is provided at the root of the blade tip winglet 2223 and the blade tip 2222 to smoothly distribute stress and greatly improve the structural reliability and service life of this critical connection.

[0355] In one specific embodiment, the blade tip winglet 2223 is tilted outward at a 20° angle to the axial direction of the hub 221 (i.e., tilted outward along the blade rotation direction D). This angle range is more suitable for the airflow characteristics of medium- and high-speed rotation scenarios, resulting in a better balance between noise reduction and airflow enhancement. Simultaneously, a 5mm radius rounded transition is provided between the root of the blade tip winglet 2223 and the blade tip 2222. This rounded transition eliminates dead airflow angles at the connection between the root and the blade tip, preventing the generation of local vortices and further reducing aerodynamic losses and noise.

[0356] In a specific implementation scenario, when the high-speed three-phase micro motor 210 starts and drives the fan blades 220 to rotate at high speed, the blades 10 push the air. In the blade tip region 2222, due to the pressure difference, the airflow tends to cross laterally from the pressure surface B to the suction surface A. At this time, the inclined arc-shaped blade tip winglets 2223 play a crucial role in blocking and guiding the airflow. They not only physically block part of the lateral leakage path, but more importantly, their special arc and tilt angle can reorganize the flow field in the blade tip region, "combing" some of the leaking airflow and guiding it back into the main airflow, while simultaneously disrupting the formation of large-scale blade tip leakage vortices. This process significantly reduces energy loss, increases effective airflow, and greatly reduces operating noise by suppressing strong vortex pulsations.

[0357] The technical effects of the above solution are as follows: On the one hand, by setting an arc-shaped protruding blade tip winglet at the blade tip, it is equivalent to adding a physical barrier at the blade tip end, which can effectively block the lateral flow between the pressure surface and the suction surface of the blade, significantly weaken the strength and size of the blade tip leakage vortex, thereby improving the fan's wind power and overall aerodynamic efficiency; on the other hand, since the blade tip leakage vortex is the main noise source, this invention fundamentally weakens the pressure pulsation caused by unsteady vortices by suppressing the generation and development of leakage vortices, thereby effectively reducing the aerodynamic noise during fan operation and improving the fan's acoustic environment.

[0358] Please continue to refer to Figures 21 and 22. The leaf roots 2221 of each blade 222 are connected in a counterclockwise direction along the surface of the annular sidewall 2212, from the top edge of the annular sidewall 2212 to the bottom edge. Each blade 222 has a radially extending twisted shape from the leaf root 2221 to the leaf tip 2222.

[0359] A key improvement of this invention lies in the three-dimensional spatial design of the blades 222. Specifically, the root portion 2221 of each blade 222 is bent counterclockwise along the surface of the annular sidewall 2212, from the top edge to the bottom edge. This "counterclockwise" direction corresponds to the rotation direction D of the fan blades. This root bending design allows the blades 222 to more smoothly "cut into" the incoming airflow during rotation, much like a propeller. This effectively reduces airflow separation on the hub surface, guiding the airflow more efficiently into the blade channel, thereby improving intake efficiency and pressure at the source.

[0360] Furthermore, each blade 222 exhibits a radially extending twisted shape from the blade root 2221 to the blade tip 2222. That is, the angle of attack (or angle of attack) of the blade 222 changes continuously from the blade root 2221 to the blade tip 2222. This design is based on a classic aerodynamic principle: when the fan rotates, the linear velocity at the hub 221 is much lower than the linear velocity at the blade tip 2222, resulting in significant differences in the angle of attack at different radii. By employing a radially twisted blade profile, it can be ensured that each radial section from the blade root 2221 to the blade tip 2222 operates at its respective optimal aerodynamic angle of attack. This significantly improves the overall aerodynamic load distribution of the blade 222, avoids local stall, and thus achieves high efficiency, high wind pressure, and low noise operation over a wide operating range.

[0361] In one specific embodiment, when the high-speed three-phase micro motor 210 starts and drives the fan blades 220 to rotate at high speed, the counterclockwise curved blade root first guides the airflow to smoothly adhere to the surface of the hub 221 and enter the blade flow channel, reducing inlet impact loss. The radially twisted blades 222 ensure that the entire blade 222, from root to tip, can efficiently perform work on the airflow, generating stable and strong wind pressure and airflow. Furthermore, the inclined arc-shaped blade tip winglets 2223 play a crucial role in the blade tip region, effectively suppressing the generation of tip leakage vortices, recaptures energy that would otherwise be lost through leakage and guides it into the main airflow, while significantly reducing the harsh noise caused by vortex rupture.

[0362] In some embodiments, each blade 222 includes a suction surface A and a pressure surface B disposed opposite to each other; wherein, in the axial direction of the hub 221, the suction surface A is located above the pressure surface B; the suction surface A is convex and formed in an outer arc shape to reduce the wind resistance of the blade 222 when rotating, and the pressure surface B is concave and formed in an inner arc shape to guide the airflow.

[0363] Specifically, the blade design of this invention constitutes a complete aerodynamic optimization system. First, referring to Figure 22, each blade 222 includes a suction surface A and a pressure surface B arranged opposite each other. In the axial direction of the hub 221 (i.e., the motor shaft direction), the suction surface A is located above the pressure surface B. The suction surface A is constructed as a convex outer arc shape; this streamlined design facilitates smooth airflow and creates a strong negative pressure in this area during rotation, thereby effectively reducing wind resistance and generating the main lift. The pressure surface B is constructed as a concave inner arc shape; its main function is to guide and pressurize the airflow, pushing it in a predetermined direction to jointly perform work.

[0364] Secondly, the root portion 2221 of each blade 222 is bent counterclockwise (corresponding to the rotation direction D) along the surface of the annular sidewall 2212 from the top edge to the bottom edge. This design allows the blade to "cut" into the air more smoothly, reducing inlet impact loss. Thirdly, each blade 222 exhibits a radially extending twisted shape from the root portion 2221 to the tip portion 2222. This allows the blade 222 to have different installation angles at different radii to accommodate different linear velocities from the hub to the tip, ensuring the entire blade operates at high efficiency.

[0365] In one embodiment, each blade 222 further includes a leading-edge wing 2224 and a trailing-edge wing 2225. The first end S1 of the leading-edge wing 2224 is connected to the first end P1 of the blade root 2221, and its second end S2 is connected to the first end P3 of the blade tail 120. The first end S3 of the trailing-edge wing is connected to the second end P2 of the blade root 2221, and its second end S4 is connected to the second end P4 of the blade tail 120, forming a closed blade shape. The leading-edge wing 2224 is located at the front of the rotation direction, and the trailing-edge wing 2225 is located at the rear of the rotation direction. In the axial direction of the hub 221, the leading-edge wing 2224 is located above the trailing-edge wing 2225.

[0366] Specifically, each blade 222 has a closed aerodynamic shape formed by the leading-edge wing 2224, the trailing-edge wing 2225, the blade root 2221, and the blade tip 2222. The leading-edge wing 2224 is located on the front side of the blade in the direction of rotation D and is the part of the blade 222 that first contacts the incoming flow; the trailing-edge wing 2225 is located on the rear side of the direction of rotation D and is the part where the airflow finally leaves the blade. This complete profile is the basic structure that enables the blade 222 to work efficiently.

[0367] In some embodiments, referring to Figure 23, the first end S1 of the leading edge wing 2224 is integrally connected to the first end P1 (front side in the rotation direction) of the blade root 2221, and the second end S2 extends to the first end P3 of the blade tip 2222, with the width smoothly transitioning from the blade root 2221 to the blade tip 2222; the first end S3 of the trailing edge wing 2225 is seamlessly connected to the second end P2 (rear side in the rotation direction) of the blade root 2221 in all directions, and its connection area not only covers the edge of the pressure surface B and suction surface A of the second end P2 of the blade root 2221, but also completely fits the trailing edge contour of the blade root 2221, ensuring that the airflow will not leak from the connection gap; the second end S4 extends smoothly along the twisted shape of the blade 222 to the second end P4 of the blade tip 2222, and precisely docks with the trailing edge structure of the blade tip 2222. In order to adapt to the size reduction characteristics of the blade 222 from the blade root to the blade tip and the change of airflow velocity, the width of the trailing edge wing 2225 adopts a smooth gradient design, which transitions evenly from the blade root 2221 to the blade tip 2222. This gradient structure can avoid airflow disturbance caused by abrupt width changes, while reducing the weight of the blade tip and improving rotational stability.

[0368] The above scheme, through the leading edge wing 2224 and trailing edge wing 2225 extending one after the other in coordination, finally forms a complete closed blade profile between the blade root 2221 and the blade tip 2222. This closed structure can build a continuous airflow channel and completely block the airflow from overflowing from the side of the blade 222.

[0369] In one embodiment, the blade tip winglet 2223 extends from the trailing edge wing 2225 to the leading edge wing 2224 in the rotation direction D, and the ratio of the length of the blade tip winglet 2223 to the length of the blade tip 2222 is 3:4 or 4:5.

[0370] Specifically, as a key dimensional optimization embodiment, as shown in Figure 24, the blade tip winglet 2223 extends from the trailing edge wing 2225 to the leading edge wing 2224 in the rotational direction D. This arrangement ensures that the blade tip winglet 2223 can cover most of the blade tip leakage path from the trailing edge wing 2225 to the leading edge wing 2224, providing maximum protection against leakage vortices.

[0371] In some embodiments, the ratio of the length L1 of the blade tip winglet 2223 to the length L2 of the blade tip 2222 (i.e., the chord length from the trailing edge winglet 2225 to the leading edge winglet 2224 at the blade tip) is limited to an optimized range, specifically 3:4 or 4:5. This specific ratio range has been carefully designed and experimentally verified. If the blade tip winglet 2223 is too short (too small), it cannot effectively cover the leakage flow in the middle and front, resulting in poor suppression; if the blade tip winglet 2223 is too long (too large, e.g., 1:1), it will increase additional weight and drag, and may introduce new structural vibration problems. Therefore, the ratio range of 3:4 to 4:5 achieves the best balance between the effectiveness of leakage suppression and the lightweight and reliability of the structure, enabling optimal aerodynamic performance improvement without excessively increasing material costs and rotational inertia.

[0372] In one specific embodiment, an arc-shaped protruding tip winglet 2223 is provided at the tip 2222 of each blade 222. The tip winglet 2223 extends from the trailing edge winglet 2225 to the front edge winglet 2224 in the direction of blade rotation, completely covering the core airflow leakage area of ​​the tip 2222. The arc radius of the tip winglet 2223 is 10mm, the protrusion height is 5mm, and its arc protrusion direction is consistent with the rotation direction of the blade 222. The length of the tip 2222 is 40mm, and the length of the tip winglet 2223 is 32mm, with a length ratio of 4:5. This ratio design allows the tip winglet 2223 to play an airflow control role without significantly increasing the weight of the blade tip. The blade tip winglet 2223 is tilted outward at a 20° angle to the axial direction of the hub 221, and a 5mm radius fillet transition is used between the root of the blade tip winglet 2223 and the blade tip 2222. This fillet transition effectively optimizes the airflow state at the root. The above angles, proportions, and fillet parameters were all optimized and determined through aerodynamic simulation software, which can minimize additional air resistance and local vortices while preventing airflow leakage.

[0373] In one embodiment, the thickness of each blade 222 and the blade tip winglet 2223 increases to a maximum thickness starting from the trailing edge winglet 2225 and extending in the rotation direction D, and decreases from their respective maximum thickness toward the leading edge winglet 2224, so as to form a blade 222 and a curved blade tip winglet 2223 that are arcuately arranged at the blade tip 2222.

[0374] Specifically, to simultaneously achieve excellent aerodynamic performance and structural strength, the present invention optimizes the thickness distribution of the blades 222 and the blade tip winglets 2223. Referring to Figure 24, the thickness of each blade 222 begins at the trailing edge winglet 2225, extends towards the rotation direction D, and gradually increases to a maximum thickness D1. Then, from its maximum thickness D1, it extends towards the leading edge winglet 2224 and gradually decreases. Similarly, the thickness of the blade tip winglet 2223 follows the same design principle, increasing to a maximum thickness D2 from the end connected to the trailing edge winglet 2225, and then decreasing towards the end connected to the leading edge winglet 2224.

[0375] In an exemplary embodiment, the thickness of the blade 222 at the tip 2222 gradually increases from 1.2 mm at the trailing edge wing 2225 along the rotational direction to 1.8 mm at a distance of about 15 mm from the trailing edge wing 2225 (i.e., the maximum thickness D1 of the blade tip 2222), and then gradually decreases to 1.0 mm in the direction of the forward edge wing 2224. The thickness of the blade tip winglet 120 increases from 1.0 mm at the end connected to the trailing edge wing 2225 along the rotational direction to 1.5 mm at the position corresponding to the maximum thickness of the blade (i.e., the maximum thickness D2 of the blade tip winglet 2223), and then decreases to 0.8 mm in the direction of the forward edge wing 2224. This gradual thickness design allows the blade 222 to naturally form a smooth arc-shaped profile at the tip 2222, while the blade tip winglet 2223 forms an arc-shaped protrusion that conforms to the airflow trajectory.

[0376] This thickness distribution pattern of "thin at the leading edge, thick in the middle, and thin at the trailing edge" constitutes a classic streamlined airfoil. Its technical advantages are: ① The thinner leading edge smoothly "cuts" and divides the incoming airflow, significantly reducing inlet drag; the gradual thinning from the thickest point to the trailing edge ensures that the airflow converges as smoothly as possible when leaving blade 222, avoiding strong vortex shedding caused by abrupt thickness changes or an excessively thick trailing edge, thus further reducing drag and noise. ② By placing the thickest region slightly forward of the middle of the blade, it matches the region of maximum aerodynamic load and centrifugal stress borne by blade 222, much like reinforcing the middle section of a beam, thus achieving maximum structural stiffness and strength with minimal material, effectively preventing deformation or vibration at high speeds.

[0377] The above scheme, through thickness distribution design, ultimately makes the cross-section of the blade 222 at the blade tip 2222 and the cross-section of the blade tip winglet 2223 present a smooth and continuous arc-shaped profile. This is a key detail for achieving efficient, low-noise and reliable operation.

[0378] In one embodiment, the ratio of the maximum thickness D1 of each blade 222 to the maximum thickness D2 of the blade tip winglet 2223 is 1:0.9, and the ratio of the maximum thickness D1 of each blade to the width D3 of the blade tip winglet 2223 is 0.9:1.

[0379] Specifically, the present invention further defines the key dimensional ratio between the blade body and the tip winglet 2223, which is the core of achieving synergistic optimization of aerodynamic and structural performance. Please refer to Figures 24 and 25, where the maximum thickness of the blade 222 is denoted as D1, the maximum thickness of the tip winglet 2223 is denoted as D2, and its width (the dimension in the tip chord direction) is denoted as D3.

[0380] In some embodiments, the ratio of the maximum thickness D1 of each blade 222 to the maximum thickness D2 of the blade tip winglet 2223 is set to 1:0.9. This means that the maximum thickness of the blade tip winglet 2223 is approximately 90% of the maximum thickness of the blade body. This ratio ensures that the blade tip winglet 2223 has sufficient structural strength and rigidity to withstand centrifugal and aerodynamic loads at high speeds, while avoiding additional drag or weight due to its excessive thickness. It makes the blade tip winglet 2223 match the main blade in strength, forming a continuous and coordinated load-bearing whole.

[0381] In some embodiments, the ratio of the maximum thickness D1 of each blade 222 to the width D3 of the blade tip winglet 2223 is set to 0.9:1. This ratio indicates that the width of the blade tip winglet 2223 is slightly larger than the maximum thickness of the blade body. This carefully designed width-to-thickness ratio is crucial: sufficient width (D3) ensures that the blade tip winglet 2223 can effectively cover and block longer leakage paths, thereby maximizing its aerodynamic benefits; while relating it to the thickness of the main blade (D1) ensures that the size of the blade tip winglet 2223 is in harmony with the aerodynamic dimensions of the entire blade 222, avoiding efficiency reduction or flow instability caused by the blade tip winglet 2223 being too wide or too narrow.

[0382] In summary, by setting the maximum thickness D1 of the blade 222 and the maximum thickness D2 of the blade tip winglet 2223 to 1:0.9, and setting the maximum thickness D1 of the blade 222 and the width D3 of the blade tip winglet 2223 to 0.9:1, the present invention establishes an optimal balance between the strength, weight, aerodynamic coverage, and coordination with the main blade of the blade tip winglet, thereby further improving the overall high-performance design of the fan in detail.

[0383] In one embodiment, the high-speed three-phase micro motor 210 has an operating voltage of 2 to 18 volts, an operating current of 0.1 to 10 amps, a rated operating power of 0.5 to 100 watts, and / or a rated operating speed greater than 12,000 RPM / MIN.

[0384] The high-speed three-phase micro motor 210 is driven by a voltage range of 2 to 18V, which can be 12V, 12.5V, 14V, 16.8V, ..., 18V. It is suitable for power supply by four batteries in series, and the operating current range is 0.1-10A to ensure stable operation at different speeds. The power range is 0.5 to 100W to meet the power requirements of portable fans.

[0385] In one embodiment, the fan blade 220 is assembled with a 36HS high-speed three-phase micro motor 210 (operating voltage 12V, operating current 1.5A, rated power 18W, rated speed 15000RPM / MIN). Tests were conducted at speeds of 12000RPM / MIN and 15000RPM / MIN. At 12000RPM, the aerodynamic noise was 42dB and the wind power output was 10m / s. At 15000RPM, the aerodynamic noise was 45dB and the wind power output was 12m / s. Compared with traditional fan blades of the same specifications (noise of 50dB and 53dB at the same speed, and wind power of 8m / s and 10m / s respectively), the noise is reduced by 8-8.5dB and the wind power is increased by 20%-25%. Even in high-load scenarios where the motor's rated speed far exceeds 12000RPM / MIN, the synergistic optimization effect of low noise and high wind power output can still be fully achieved.

[0386] In one specific embodiment, the hub 221 is constructed with an annular sidewall 2212, the inner diameter of which is 20mm and the height is 15mm. It is adapted to the outer periphery of the output terminal of a high-speed three-phase micro motor 210 of model 36HS. This model of motor has a working voltage of 12 volts, a working current of 1.5 amps, a rated working power of 18 watts, and a rated working speed of up to 15000 RPM / MIN, which fully covers the parameter range of "working voltage 2 to 18 volts, working current 0.1 to 10 amps, rated power 0.5 to 100 watts and rated speed greater than 12000 RPM / MIN". The inner surface of the annular sidewall 2212 is provided with anti-slip texture to ensure that the fan blade 220 is firmly connected to the motor 210 and to avoid relative slippage during rotation.

[0387] The technical effects of the above solution are as follows: On the one hand, by setting an arc-shaped protruding blade tip winglet at the blade tip, it is equivalent to adding a physical barrier at the blade tip end, which can effectively block the lateral flow between the pressure surface and the suction surface of the blade, significantly weaken the strength and size of the blade tip leakage vortex, thereby improving the fan's wind power and overall aerodynamic efficiency; on the other hand, since the blade tip leakage vortex is the main noise source, this invention fundamentally weakens the pressure pulsation caused by unsteady vortices by suppressing the generation and development of leakage vortices, thereby effectively reducing the aerodynamic noise during fan operation and improving the fan's acoustic environment.

[0388] Example 5

[0389] Please refer to Figures 26 and 27. This invention provides an active noise reduction method for a portable fan. Taking the application of this method to the portable fan in Figure 1 as an example, the method includes the following steps:

[0390] Step S11: Obtain the noise signal.

[0391] In one embodiment, the noise signal is a dynamic composite noise signal generated by the portable fan during operation, including intake noise, exhaust noise, fan blade noise, and / or motor noise.

[0392] Among them, intake noise and exhaust noise are the noise signals generated by the casing of the portable fan when air is intake and exhaust, respectively, and fan blade noise and motor noise are the noise signals generated by the fan blades and motor of the portable fan when they are running.

[0393] In some embodiments, the process of acquiring noise signals by the portable fan may specifically include: in response to the operation of the portable fan, acquiring dynamic composite noise signals in real time based on a signal acquisition device disposed in the portable fan.

[0394] Specifically, during the operation of a portable fan, the air inlet and shroud of the casing draw in a large amount of air, resulting in a corresponding level of intake noise. Similarly, the air outlet and shroud of the casing expel a large amount of air, generating exhaust noise. Furthermore, the rotation of the fan blades interacts with the air, creating pressure pulsations and producing blade noise. Finally, the rotor of the motor cuts magnetic lines of force, causing friction between the rotor and stator and generating motor noise. Therefore, these four main static noise signals dynamically combine to form a comprehensive noise signal that is transmitted to the user's hearing system during the use of an active noise-canceling fan (e.g., while walking, running, or remaining stationary). In some embodiments, the signal acquisition device follows the user's usage scenario, collects in real time the comprehensive noise signal dynamically composed of the above-mentioned intake noise, exhaust noise, fan blade noise and / or motor noise, and sends it to the signal processor for detailed analysis and processing.

[0395] In some embodiments, the intake noise in the dynamic composite noise signal includes the static intake noise generated by the active noise-canceling fan when it is in fixed use and the dynamic intake noise generated by the user when it is in motion; the exhaust noise includes the static exhaust noise generated by the active noise-canceling fan when it is in fixed use and the dynamic exhaust noise generated by the user when it is in motion; the fan blade noise includes the static fan blade noise generated by the active noise-canceling fan when it is in fixed use and the dynamic fan blade noise generated by the user when it is in motion; and the motor noise includes the static motor noise generated by the active noise-canceling fan when it is in fixed use and the dynamic fan blade noise generated by the user when it is in motion.

[0396] Specifically, in practical applications, this active noise-canceling fan can have multiple usage states, and the corresponding dynamic composite noise signal generated in each usage state is different. For example, when a user places it on a desktop as a desktop fan, the active noise-canceling fan is in a stationary state, and the corresponding dynamic composite noise signal generated is static noise. Or, when a user holds it in their hand and moves it at irregular speeds and directions, the active noise-canceling fan is in an irregular operating state, and the corresponding dynamic composite noise signal generated is dynamic noise.

[0397] In some embodiments, the signal acquisition device is disposed within the internal cavity of the portable fan, and the signal acquisition device includes at least one sound sensor, and at least one sound sensor is disposed at at least one target point within the cavity to collect noise signals near each target point in real time.

[0398] The sound sensors, distributed at various target points within the cavity, are used to collect noise signals generated by relevant parts of the portable fan during operation. For example, during operation, the fan blades rotate and interact with the air, generating pressure pulsations and corresponding noise. Alternatively, the torque generated by the fan blades is transmitted to the motor via the transmission mechanism, also producing noise, primarily including bearing noise, gear noise, and motor noise. Furthermore, friction between the rotor and stator when the motor rotor cuts magnetic lines of force generates noise. Additionally, high-speed airflow, unstable airflow, and the interaction between the airflow and the blades can produce aerodynamic noise. Therefore, the sound sensors at various locations can be used to collect these noise signals.

[0399] In some embodiments, the process of a portable fan acquiring dynamic composite noise signals in real time based on a signal acquisition device disposed in the portable fan may specifically include: acquiring dynamic composite noise signals near each target location in real time based on at least one sound sensor.

[0400] The target locations include at least the edge of the air inlet of the portable fan, the edge of the air outlet, the vicinity of the motor, the vicinity of the fan blades, and the vicinity of the center of the air duct.

[0401] Specifically, since the noise of a portable fan is mainly generated when the fan blades rotate, in one possible implementation, multiple sound sensors include a first microphone and a second microphone. The first microphone is disposed on the blades of the fan blades and is configured to collect the noise signal of the blades, and the second microphone is disposed on the hub of the fan blades and is configured to collect the noise signal of the hub.

[0402] In addition to the significant noise generated by the rotation of the hub and blades, noise signals are also generated when the rotor assembly of the motor cuts magnetic lines of force and when there is friction between the rotor assembly and the stator assembly. In some embodiments, the multiple sound sensors also include a third microphone, which is located on the inner wall near the motor in the cavity and is configured to collect the noise signals of the motor.

[0403] In other embodiments, although the related technology reduces the noise generated when air flows through the cavity by improving the structure of the air casing, some noise is still inevitably generated when air flows through the cavity. Therefore, in some embodiments, the multiple sound sensors also include a fourth microphone. There can be multiple fourth microphones, which are arranged on the air flow path in the cavity. For example, the fourth microphones are respectively arranged on the inner wall near the air inlet, air outlet and the center of the air duct in the cavity, and are configured to collect noise signals from the air inlet, air outlet and the center of the air duct.

[0404] Step S12: Based on the pre-trained noise reduction model, noise control processing is performed on the noise signal to obtain noise control instructions.

[0405] In one embodiment, the pre-trained noise reduction model can perform phase inversion processing on the noise signal to obtain inverted signal data, and generate noise control commands based on the inverted signal data.

[0406] The noise control command includes inverse signal data that is opposite in phase to the noise signal but has the same frequency and amplitude.

[0407] In some embodiments, the pre-trained noise reduction model can determine the spectral range and magnitude of the noise signal by analyzing the Hanning window spectrum of the noise signal, and calculate the corresponding inverted signal data.

[0408] Specifically, when analyzing the spectrum of a noisy signal, using the Hanning window is an effective method to reduce spectral leakage and improve the accuracy of spectrum estimation.

[0409] Step S13: A noise reduction signal is issued based on the noise control command to perform active noise control on the portable fan.

[0410] Within a preset error tolerance range, the noise reduction signal and the noise signal are out of phase but have the same frequency and amplitude. This is used to perform destructive interference on the noise signal, thereby achieving active noise control of the fan.

[0411] Specifically, sound is composed of a certain spectrum. The spectrum of the noise reduction signal is exactly the same as the noise signal to be eliminated, but the phase is exactly opposite. That is, a phase difference of 180° can completely cancel out the noise signal. In this way, after the noise reduction signal interferes with and interferes with the sound, the new sound wave generated can be so weak that it is inaudible to the human ear, thereby reducing the impact of motor noise on humans.

[0412] It should be understood that signal acquisition equipment or environmental noise measurement may be affected by external factors, such as background noise and temperature changes, which may lead to inaccurate signal acquisition. Different noise reduction algorithms have their applicable ranges and limitations, and some algorithms may not be able to effectively handle noise in all frequency ranges, resulting in inaccurate noise reduction signal generation. Alternatively, the structure around the fan (such as walls, the ground, and other objects) may affect the propagation characteristics of sound waves, producing reflection, diffraction, or resonance, thereby changing the signal acquisition effect. Ultimately, this may result in the generated noise reduction signal not being completely 180° out of phase with the noise signal, and / or not having the same frequency and amplitude. Therefore, a preset error allowable range can be set. As long as the generated noise reduction signal and the noise signal are within this error allowable range, they are considered to be out of phase and have the same frequency and amplitude.

[0413] In an exemplary embodiment, referring to FIG27, FIG27 is a schematic flowchart of an embodiment of active noise control for a portable fan according to this application. In step S13, the portable fan emits a noise reduction signal based on a noise control command to perform active noise control on the portable fan, which can be achieved in the following manner:

[0414] Step S131: Amplify the target noise reduction signal or inverted signal data carried in the noise control command to obtain a power amplified signal.

[0415] In some embodiments, the portable fan can receive noise control commands through a power amplifier, and then amplify the target noise reduction signal or inverted signal data carried in the noise control commands to obtain a power amplified signal.

[0416] Specifically, the power amplifier includes a power amplifier circuit, which includes a signal input terminal and a signal output terminal. The signal input terminal of the power amplifier circuit is used to receive noise control commands. Then, the power amplifier circuit amplifies the target noise reduction signal or inverted signal data carried in the noise control commands. Finally, the power amplifier circuit outputs the amplified signal to the sound player through the signal output terminal of the power amplifier circuit.

[0417] Step S132: Based on the power amplified signal, a noise reduction signal with the opposite phase, frequency and amplitude to the noise signal is emitted at each target point to perform destructive interference on the noise signal.

[0418] In some embodiments, the portable fan can play a power-amplified signal through a sound player located at each target point, causing the target noise-reducing signal or inverted signal data to interfere with the noise signal, thereby canceling out part or all of the noise signal. The sound player is used to emit a noise-reducing signal that is out of phase with the combined noise signal but has the same frequency and amplitude, based on the power-amplified signal.

[0419] In some embodiments, the portable fan performs digital-to-analog conversion and signal amplification on the target noise-reduced signal or inverted signal data, and then outputs it to a sound player for playback of the noise-reduced signal. This process is called active noise cancellation, and the principle of active noise cancellation is shown in Figure 3. The noise-reduced signal is mainly used to suppress noise signals from the original environment.

[0420] In some embodiments, the portable fan may include multiple sound players, and the sound players and sound sensors are in a one-to-one correspondence in terms of position, so that the noise reduction signals played by different sound players can eliminate the corresponding noise signals.

[0421] Specifically, since the noise of a portable fan is mainly generated when the fan blades rotate, in one possible implementation, multiple sound players include a first speaker and a second speaker. The first speaker is disposed on the blades of the fan blades and is configured to play an inverted noise-canceling signal to the rotating blades. The second speaker is disposed on the hub of the fan blades and is configured to play an inverted noise-canceling signal to the rotating hub.

[0422] In this way, the first speaker can play an inverse noise-reduction signal to the rotating blades according to the noise control command issued by the portable fan, so as to cancel the noise signal generated in the target area, thereby partially or completely eliminating the noise generated by the fan blades when rotating. Similarly, the second speaker can play an inverse noise-reduction signal to the rotating hub according to the noise control command issued by the portable fan, so as to cancel the noise signal generated in the target area, thereby partially or completely eliminating the noise generated by the hub of the fan blades when rotating.

[0423] Furthermore, in addition to the significant noise generated by the rotation of the hub and blades, noise signals are also generated when the rotor assembly of the motor cuts magnetic lines of force and when there is friction between the rotor assembly and the stator assembly. In some embodiments, the multiple sound players also include a third speaker disposed on the inner wall near the motor within the cavity and configured to play an inverse noise-reduced signal to the running motor.

[0424] In this way, the third speaker can play an inverse noise reduction signal to the running motor according to the noise control command issued by the portable fan, so as to cancel the noise signal generated in the target area, thereby partially or completely eliminating the noise generated by the motor of the portable fan during operation.

[0425] In other embodiments, although the related technology reduces the noise generated when air flows through the cavity by improving the structure of the air casing, some noise is still inevitably generated when air flows through the cavity. Therefore, in some embodiments, the multiple sound players also include a fourth speaker. There can be multiple fourth microphones, which are arranged on the air flow path in the cavity. For example, the fourth speakers are respectively arranged on the inner wall near the air inlet, air outlet and the center of the air duct in the cavity, and are configured to play inverse noise-reducing signals to the target area near the air inlet, air outlet and the center of the air duct.

[0426] In this way, the fourth speaker can play inverse noise reduction signals to the target area near the air inlet, air outlet and air duct center according to the noise control command issued by the portable fan, so as to cancel the noise signal generated in the target area and thus eliminate the noise generated in the air inlet, air outlet and air duct center in the cavity when the portable fan is running.

[0427] In other embodiments, the sound player for each target area may also include multiple noise-canceling speakers, with at least two noise-canceling speakers facing different directions.

[0428] In other words, when collecting noise signals, multiple signal collectors will collect noise signals from different parts of the portable fan. In order to specifically cancel different noise signals, different cancellation sound wave signals need to be generated and played according to the propagation direction of different noise signals. Therefore, during playback, the propagation direction of the noise reduction signal for different noise signals will also be different. Thus, the sound playback direction of multiple noise reduction speakers is different in order to eliminate noise signals propagating from various directions.

[0429] In some implementations, the number of noise-canceling speakers can be an even number, with multiple noise-canceling speakers arranged in a circle, and the orientations of two opposing noise-canceling speakers facing away from each other.

[0430] For example, the number of noise-canceling speakers can be four or six. When there are four noise-canceling speakers, adjacent speakers are arranged at a 90-degree angle, and all speakers face outwards. When there are six noise-canceling speakers, adjacent speakers are arranged at a 60-degree angle, and opposite speakers face back to back. In this way, multiple noise-canceling speakers can play noise-canceling wave signals in all directions to better eliminate noise.

[0431] The technical effect of the above solution is as follows: First, the method acquires a noise signal; this noise signal is a dynamic comprehensive noise signal generated by the portable fan during operation, including intake noise, exhaust noise, fan blade noise, and / or motor noise; then, it performs noise control processing on the noise signal based on a pre-trained noise reduction model to obtain a noise control command; finally, it issues a noise reduction signal based on the noise control command to actively control the noise of the portable fan; wherein, within a preset error allowable range, the noise reduction signal is out of phase with the noise signal and has the same frequency and amplitude, and is used to perform destructive interference on the noise signal. In this way, on the one hand, the pre-trained noise reduction model is used to process the noise signal to obtain noise control commands, and then these commands are used to actively control the noise of the portable fan, thereby optimizing the noise reduction process of the portable fan, reducing the complexity of executing the active noise reduction program, and reducing labor costs. On the other hand, by differentiating itself from existing technologies, this solution, through the rational design of the active noise reduction program, can dynamically analyze various noise signals, including intake noise, exhaust noise, fan blade noise, and / or motor noise. This allows for the real-time acquisition of dynamic comprehensive noise signals generated inside and outside the fan cavity during operation, and the issuance of corresponding noise reduction signals based on these dynamic comprehensive noise signals, thereby achieving active noise control of the portable fan to reduce the noise level during operation.

[0432] In an exemplary embodiment, referring to FIG28, FIG28 is a schematic flowchart of an embodiment of obtaining noise control instructions in this application. In step S12, the portable fan performs noise control processing on the noise signal based on a pre-trained noise reduction model to obtain noise control instructions, which can be implemented in the following manner:

[0433] Step S121: Classify the noise signal based on the pre-trained classification network to determine the noise scene category in which the portable fan is located.

[0434] In some embodiments, the pre-trained denoising model pre-stores multiple trained learning networks, which can correspond to multiple noise scene categories. Scene categories can include train stations, subway cars, and buses, or specific environmental noises such as vehicle processing plants or machinery manufacturing plants. This application does not impose specific limitations here. Thus, based on the noise scene category, the denoising model can access / call the stored active denoising learning network corresponding to that noise scene category and applicable to that noise scene category.

[0435] In other embodiments, the noise scene category may also be related to the user's actual usage state of the portable fan, and the corresponding noise scene category may differ in each usage state. For example, when the user places it on a table as a desktop fan, the portable fan is in a stationary state, and its corresponding noise scene category is static noise scene; or when the user holds it and moves it at irregular speeds and directions, the portable fan is in an irregular operating state, and its corresponding noise scene category is dynamic noise scene.

[0436] In some embodiments, the learning network can utilize various classification algorithms to classify noise scene categories, such as, but not limited to, logistic regression, Gaussian mixture model-based classification, hidden Markov model-based classification, and any of the classification neural networks. To improve the accuracy of the classification algorithm and reduce the computational complexity, the learning network can also enable the portable fan to communicate with a smart device to obtain its current location from its GPS unit, such as, but not limited to, train stations, tunnels, subway cars, theaters, etc., thereby enabling the classification of noise scenes based on the current location. Among these classification algorithms, the classification neural network, for example, can be pre-trained using a set of training samples consisting of speech signals from various noise scenes. The trained classification neural network can also be stored on the noise reduction model for the portable fan to access at any time.

[0437] Step S122: Based on the noise scene category, call the corresponding noise reduction signal database to perform signal matching processing on the noise signal, determine the target noise reduction signal that matches the noise signal, and generate a noise control command based on the target noise reduction signal.

[0438] Each noise scene category corresponds to a noise reduction signal database, and each noise reduction signal database is used to store noise reduction signals that are opposite in phase but have the same frequency and amplitude as various preset noise signals.

[0439] Understandably, the noise reduction model can use a learning network to classify the received noise signal, and then, based on the determined noise scene category, call the noise reduction signal database to determine the target noise reduction signal that matches the noise signal. Based on the target noise reduction signal, it generates noise control instructions, thereby using the noise control instructions to perform noise reduction processing on the noise signal and provide the user with a noise-reduced audio signal.

[0440] For example, when a user holds a portable fan and moves it at irregular speeds and directions, most of the noise is generated by the noise signal produced when air flows through the cavity. The portable fan in this noise scenario receives noise signals containing air inlet, air outlet, and air duct center. At this time, the noise reduction model calls a pre-stored learning network corresponding to the noise scenario to determine its noise scenario category, and then calls the corresponding noise reduction database based on the learning network to perform noise reduction processing on the noisy audio signal.

[0441] In some embodiments, the noise reduction model is also used to determine whether the noise scene category has changed based on the input noise signal, and if the noise scene category has changed, to call the stored noise reduction signal database corresponding to the changed noise scene category to generate a new noise control instruction.

[0442] It is understandable that when a user uses a portable fan, the noise environment in which the noise signal is generated will frequently change. For example, when a user is in a subway station, the noise environment in which they are in is generated by announcements and human voices, which is the first noise environment. When the user enters the subway car from the subway station, the noise environment in which they are in is generated by the movement of the train, which is the second noise environment. It can be seen that the noise reduction model can use the corresponding learning network to perform noise reduction processing in the first noise environment. When the user changes from the first noise environment to the second noise environment, the model can determine the change in noise environment category based on the confirmation result of the classification of the received morning signal, and then call the learning network corresponding to the changed noise environment category, that is, the second noise environment category, to perform noise reduction processing. In this way, noise signals can be denoised in real time when the noise scene category changes, and the denoising processing of the current learning network can be continuously used even when the noise scene category does not change. This saves the computational resources of the denoising model and improves the computational speed while continuously denoising. It also avoids the denoising model having to call up the stored learning network again when it is confirmed that the noise scene category has not changed.

[0443] In some embodiments, the learning network includes a Long Short-Term Memory (LSTM) network or a Gated Recurrent Unit (GRU) with a depth of less than 4 layers. LSTM is a type of Recurrent Neural Network (RNN). LSTM uses a gating mechanism to enable the recurrent neural network to not only remember past information but also selectively forget less important information to model long-term contextual relationships. GRU, based on this idea, reduces the gradient vanishing problem while preserving long-term sequence information. Furthermore, since a smaller depth and fewer layers result in faster computation, a learning network depth of less than 4 layers effectively ensures the speed of noise reduction processing.

[0444] In some embodiments, the learning network corresponding to each noise scene is pre-trained on the denoising model, and the pre-training is performed separately based on training sample sets of different noise scene categories. The training samples of each noise scene category include noisy signals and noise-free signals of the corresponding noise scene category.

[0445] In one exemplary embodiment, referring to FIG29, FIG29 is a schematic flowchart of another embodiment of obtaining noise control instructions in this application. The process of the portable fan performing noise control processing on the noise signal based on a pre-trained noise reduction model to obtain noise control instructions in step S12 can also be implemented in the following ways:

[0446] Step S123: Extract the noise amplitude sequence from the noise signal, compare the noise amplitude sequence with the preset amplitude threshold, and obtain the evaluation result.

[0447] In some embodiments, the portable fan can acquire a noise signal using an amplitude comparator and extract the corresponding noise amplitude sequence from the noise signal to compare and evaluate the noise amplitude sequence with a preset amplitude threshold to obtain an evaluation result.

[0448] Step S124: When the evaluation result is that the noise amplitude sequence is greater than the amplitude threshold, the noise signal is phase-inverted based on the noise reduction model to obtain inverted signal data, and noise control instructions are generated based on the inverted signal data.

[0449] Step S125: When the evaluation result is that the noise amplitude sequence is less than or equal to the amplitude threshold, the active noise control procedure is terminated.

[0450] In some embodiments, the portable fan is also used to acquire evaluation results, and when the evaluation result is that the noise amplitude sequence is greater than the amplitude threshold, to perform phase inversion processing on the noise signal to obtain inverted signal data, and to generate noise control instructions based on the inverted signal data; or, when the evaluation result is that the noise amplitude sequence is less than or equal to the amplitude threshold, to end the noise reduction process.

[0451] Specifically, an amplitude comparator, an analog-to-digital converter, and a computer chip can be incorporated into a portable fan, and these three components can form an automated signal processing system based on amplitude comparison and active noise reduction.

[0452] The technical advantage of the above solution is that by combining signal processing and intelligent control technologies through an automated signal processing system, it can adapt to complex and ever-changing noise environments.

[0453] In an exemplary embodiment, referring to FIG30, FIG30 is a schematic flowchart of an embodiment of extracting a noise amplitude sequence according to this application. In step S123, the process of the portable fan extracting the noise amplitude sequence from the noise signal can be implemented in the following manner:

[0454] Step a1: Perform real-time filtering on the noise signal to obtain the filtered noise signal.

[0455] Among them, the portable fan can use a filter to perform real-time filtering of the noise signal to obtain the filtered noise signal.

[0456] Specifically, the filter is used to perform real-time filtering on the static noise signals collected by each sound sensor to obtain the filtered noise signal;

[0457] In some embodiments, filtering is used to resolve frequency aliasing in audio signals. When discretizing analog signals, a low-pass filter can be used to sample the signals to obtain filtered noise signals.

[0458] In other embodiments, the portable fan includes at least a plurality of filters. These filters include, but are not limited to, IIR (Infinite Impulse Response) filters and biquad filters. Because biquad filters integrate the characteristics of, for example, high-pass filters, low-pass filters, frequency equalization filters, and notch filters, the combination of these filters reduces the noise frequency band of the noise signal, achieving the initial goal of reducing specific noise signals.

[0459] Step a2 involves performing signal fusion processing on the filtered noise signal to obtain a dynamically composed composite noise signal.

[0460] The portable fan can use a signal synthesizer to fuse the filtered noise signals to obtain a dynamically composed composite noise signal.

[0461] Specifically, the signal synthesizer can transcode multiple filtered noise signals into a single composite noise signal using object-based audio encoding. In some embodiments, the signal synthesizer re-encodes the multiple filtered noise signals according to the NGA audio encoding format (i.e., object-based audio encoding), that is, it transcodes the multiple filtered noise signals. In this way, all the noise signals are merged into a single composite noise signal, so that only one decoder is needed for signal amplification. The object-based audio encoding method can be AC-4, MPEG-H, DTS-UHD, but is not limited to these.

[0462] In one embodiment, multiple filtered noise signals can be dynamically transcoded and fused into a single composite noise signal using an audio mixer or audio interface. The core principle of this audio mixer or interface is to dynamically generate a composite audio signal by combining, adjusting, and processing the amplitude and frequency response of multiple filtered static noise signals. In this way, multiple noise sources can be mixed in a balanced manner without loss of sound quality, thus achieving an ideal noise reduction effect.

[0463] In some embodiments, this audio mixer is specifically designed for mixing multiple audio signals. Its basic functions include: ① Each input signal from its input channels can be connected to the mixer via an independent channel. ② Each input channel is equipped with a volume knob to adjust the volume ratio of different signals. ③ It is equipped with an equalizer to adjust the gain of each frequency band to optimize sound quality. ④ It dynamically synthesizes all adjusted signals into a single, integrated output signal within the mixer, which is then output through the mixer's output port, which can be connected to devices such as speakers.

[0464] In some embodiments, this audio interface is used to convert multiple audio signals into digital signals and connect to a computer or other digital audio processing device. Its basic functions include: ① supporting multi-channel input connections from multiple audio sources. ② internally including a converter to convert analog audio signals into digital signals, and potentially performing some basic mixing processing. ③ it can be used with a digital audio workstation (DAW), allowing users to adjust mixing within the software, such as volume, panning, and effects, with a final output as a single path.

[0465] Step a3: Amplify the combined noise signal to obtain the amplified combined signal.

[0466] The portable fan can amplify the overall noise signal using a signal amplifier to obtain a comprehensive amplified signal.

[0467] In some embodiments, the signal amplifier is used to enhance the amplitude of a composite noise signal to improve its strength and quality during transmission, processing, or output. The signal amplifier can be an audio amplifier or an radio frequency amplifier, capable of amplifying minute noise signals to a sufficient level for subsequent processing or output. Furthermore, by reducing noise and distortion, the signal amplifier can improve the clarity and reliability of the noise signal. Additionally, the signal amplifier can aid in signal matching between different devices, ensuring their effective operation.

[0468] Step a4: Perform analog-to-digital conversion on the amplified signal to obtain the corresponding pulse code signal, and extract the noise amplitude sequence from the pulse code signal.

[0469] The portable fan can perform analog-to-digital conversion on the amplified signal using an analog-to-digital converter to obtain the corresponding pulse code signal.

[0470] In some embodiments, the pulse-coded signal is an audio pulse-code modulation (PCM) signal.

[0471] Specifically, an analog-to-digital converter (ADC) is an electronic device or circuit that converts analog signals into digital signals. This process, called analog-to-digital conversion, aims to enable analog signals (i.e., amplified signals) to be processed by digital computers or portable fans.

[0472] In some embodiments, the basic steps of analog-to-digital conversion are as follows:

[0473] ① Input amplified signal: Typically, this amplified signal is an amplified analog signal, such as the output from an audio amplifier, temperature sensor, or other sensor.

[0474] ② Sampling: The analog-to-digital converter detects the input analog signal at a certain sampling frequency. This frequency needs to be higher than the Nyquist frequency of the signal (generally twice the signal frequency) to ensure signal integrity.

[0475] ③ Quantization: Converting the sampled analog signal values ​​into discrete digital values. Quantization errors may occur at this stage.

[0476] ④ Encoding: The quantized value is encoded into a digital signal, usually in binary encoding form (such as pulse code modulation, PCM), and output as a digital signal.

[0477] In some embodiments, Pulse Code Modulation (PCM) is a digital signal representation method widely used in the digital representation of audio, video, and other analog signals. Its characteristics include: signal discretization: PCM converts continuous analog signals into a series of discrete digital values ​​through sampling and quantization; energy efficiency and bandwidth efficiency: digital signals encoded with PCM are less susceptible to noise interference during transmission, and compression techniques can reduce transmission bandwidth.

[0478] Example 6

[0479] Please refer to Figure 31. This invention provides a method for reducing motor noise in a portable fan. Taking the application of this method to the control component of the portable fan in Figure 1 as an example, the method includes the following steps:

[0480] Step S21: Obtain the motor noise generated by the portable fan during operation.

[0481] Motor noise includes mechanical vibration noise, electromagnetic noise, and aerodynamic noise of the drive motor.

[0482] Specifically, when the portable fan is running, the drive motor generates motor noise inside and outside the cavity, and this motor noise propagates in the form of an audio signal. Among the motor noise, the motor noise generated by the drive motor 1 during operation, such as mechanical vibration noise, electromagnetic noise, and aerodynamic noise, is the main source of noise for the fan.

[0483] In some embodiments, mechanical vibration noise is the sound generated by the vibration of internal mechanical components of the motor during relative motion due to friction, collision, imbalance, or structural resonance, which is transmitted into the air through the motor's connecting components. Electromagnetic noise is the sound generated when the electromagnetic force (attraction or repulsion) between the stator and rotor of the motor fluctuates periodically due to changes in the magnetic field during operation, causing vibrations in structures such as the iron core and housing, which are then transmitted through the air. Its core is the "periodic change of electromagnetic interaction". Aerodynamic noise is the sound generated when the internal or external air is disturbed (such as by airflow cutting, turbulence, or pressure changes) during motor operation. Its core is the "vibration of air particles". For example, when the motor rotor rotates, it drives the internal air (such as the air in the gap between the stator and rotor) to flow. If the gap is uneven or there are protruding structures (such as the ends of the coils), it will cause air turbulence and generate high-frequency airflow noise.

[0484] Step S22: When the signal strength of the motor noise is greater than a preset strength threshold, a noise control command is generated based on the motor noise.

[0485] In some embodiments, a pre-trained noise reduction model is pre-stored in the control component. This pre-trained noise reduction model can perform phase inversion processing on various motor noise signals to obtain inverted signal data, and generate corresponding noise control commands based on various inverted signal data.

[0486] The noise control command includes inverse signal data that is opposite in phase to the motor noise signal but has the same frequency and amplitude.

[0487] In some embodiments, the pre-trained noise reduction model can determine the spectral range and magnitude of the motor noise signal by analyzing the Hanning window spectrum of the motor noise signal, and calculate the corresponding inverted signal data. Then, the noise reduction model generates noise control commands based on the inverted signal data. When the inverted signal in the noise control command is superimposed on the motor noise signal, they will cancel each other out within the same frequency range, thereby achieving the effect of noise reduction or interference suppression.

[0488] In some embodiments, the noise reduction model can be integrated into the fan control component to have signal processing capabilities. The control component can be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it can also be a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), an embedded ARM processor, or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. The general-purpose processor can be a microprocessor; the computer chip can also be any conventional processor, etc., and this application does not specifically limit its capabilities.

[0489] Step S23: Based on the noise control command, generate and send noise reduction signals for mechanical vibration noise, electromagnetic noise and aerodynamic noise respectively, so as to perform destructive interference on motor noise.

[0490] In one embodiment, the control component can control the noise suppressor to emit corresponding noise reduction signals based on various noise control commands in order to perform active noise control on the portable fan.

[0491] Within a preset error tolerance range, each noise reduction signal has the opposite phase and the same frequency and amplitude as its corresponding motor noise signal. This is used to perform destructive interference on mechanical vibration noise, electromagnetic noise, and aerodynamic noise, respectively, in order to achieve active noise control of the drive motor 130.

[0492] Specifically, sound is composed of a certain spectrum. The spectrum of the noise reduction signal is exactly the same as the noise signal to be eliminated, but the phase is exactly opposite. That is, a phase difference of 180° can completely cancel out the noise signal. In this way, after the noise reduction signal interferes with and interferes with the sound, the new sound wave generated can be so weak that it is inaudible to the human ear, thereby reducing the impact of motor noise on humans.

[0493] It should be understood that noise acquisition devices or environmental noise measurements may be affected by external factors, such as background noise and temperature changes, which may lead to inaccurate signal acquisition. Different noise reduction algorithms have their applicable ranges and limitations, and some algorithms may not be able to effectively handle noise in all frequency ranges, resulting in inaccurate noise reduction signal generation. Alternatively, structures around the fan (such as walls, the ground, and other objects) may affect the propagation characteristics of sound waves, causing reflection, diffraction, or resonance, thereby changing the signal acquisition effect. Ultimately, this may result in the generated noise reduction signal not being completely 180° out of phase with the motor noise signal, and / or not having the same frequency and amplitude. Therefore, a preset error allowable range can be set. As long as the generated noise reduction signal and the noise signal are within this error allowable range, they are considered to be out of phase and have the same frequency and amplitude.

[0494] In other embodiments, the three main motor noise signals described above will dynamically combine into a comprehensive noise signal and be transmitted to the user's hearing system during the use of the portable fan (e.g., while the user is walking, running, or remaining stationary with the portable fan in hand). In some embodiments, the control component follows the user's usage scenario, collects the comprehensive noise signal dynamically composed of the aforementioned mechanical vibration noise, electromagnetic noise, and aerodynamic noise in real time, and performs detailed analysis and processing on it.

[0495] Specifically, in practical applications, this portable fan can have multiple usage states, and the corresponding dynamic composite noise signal generated in each usage state is different. For example, when a user places it on a desktop as a desktop fan, the portable fan is in a stationary state, and the corresponding dynamic composite noise signal generated is static noise. Or, when a user holds it in their hand and moves it at irregular speeds and directions, the portable fan is in an irregular operating state, and the corresponding dynamic composite noise signal generated is dynamic noise.

[0496] The technical effects of the above solution are as follows: On the one hand, through the linkage mechanism of noise acquisition, processing and suppression, the various noises generated by the fan drive motor are accurately reduced, improving the user's comfort and experience when using the portable fan; on the other hand, by using a method different from the existing technology, noise control commands generated by preset thresholds and algorithms are used to generate and issue noise reduction signals for the mechanical vibration noise, the electromagnetic noise and the aerodynamic noise respectively, so as to perform noise cancellation interference, thereby realizing active noise reduction and accurate processing of the fan drive motor noise, so as to reduce the noise level generated by the motor during operation.

[0497] In one embodiment, a drive motor and an impeller assembly are disposed inside the portable fan. The impeller assembly includes a conical cavity for enclosing and fixing the drive motor.

[0498] Specifically, step S21 involves acquiring the motor noise generated by the portable fan during operation, including: when the drive motor is running, acquiring electromagnetic noise inside and outside the conical cavity based on a preset noise acquisition device.

[0499] In some embodiments, the noise collector can collect motor noise signals within the cavity in real time in response to the operation of the drive motor. Specifically, the noise collector is located inside the air supply section and may include multiple microphone arrays and multiple vibration sensors. The microphone arrays are distributed at a preset angle around the drive motor to collect motor noise signals propagating through the air; the vibration sensors are fixed to the motor bearing housing and stator housing with thermally conductive adhesive to monitor mechanical vibration data in real time. In some embodiments, the noise collector collects the motor noise generated by the drive motor during operation in real time, including mechanical vibration noise, electromagnetic noise, and aerodynamic noise, and sends it to a noise processor for separate detailed analysis and processing.

[0500] In one embodiment, the noise collector includes at least one microphone; wherein the at least one microphone is disposed at at least one target point within the cavity to collect motor noise signals near each target point in real time. Specifically, the noise collector includes a first microphone disposed on the inner wall of the conical cavity, a second microphone disposed on the outer surface of the hub, and a third microphone disposed on the drive motor.

[0501] In some embodiments, electromagnetic noise inside and outside the conical cavity is collected based on a preset noise collector, including: collecting electromagnetic noise generated in the inner wall of the conical cavity based on the first pickup; and / or collecting aerodynamic noise generated in the outer surface of the hub based on the second pickup; and / or collecting mechanical vibration noise generated in the shaft of the drive motor based on the third pickup.

[0502] In an exemplary embodiment, referring to FIG32, FIG32 is a schematic flowchart of an embodiment of generating noise control instructions in this application. In step S22, the process of the portable fan generating noise control instructions based on the motor noise can be implemented in the following manner:

[0503] Step S221 involves performing frame segmentation, windowing, and time-frequency transformation on the mechanical vibration noise, electromagnetic noise, and aerodynamic noise respectively to obtain multiple corresponding frequency domain noise frames.

[0504] In some embodiments, the control component performs signal preprocessing on the mechanical vibration noise collected by the third pickup, the electromagnetic noise collected by the first pickup, and the aerodynamic noise collected by the second pickup, respectively. This includes: performing frame segmentation with a frame length of 20ms and an overlap rate of 50% to balance time resolution and frequency resolution; applying a Hanning window to the mechanical vibration noise (to reduce spectral leakage), a rectangular window to the electromagnetic noise (to preserve impulse characteristics), and a Blackman window to the aerodynamic noise (to improve high-frequency resolution); and converting the time-domain signal to the frequency domain using a Fast Fourier Transform (FFT, 1024 points) to obtain multiple frequency-domain noise frames corresponding to the noise (frequency resolution ≤ 20Hz).

[0505] Step S222: Determine the noise suppression frame corresponding to each motor noise.

[0506] Among them, multiple noise suppression frames correspond one-to-one with multiple frequency domain noise frames, and the corresponding noise suppression frames and frequency domain noise frames have opposite phases, the same amplitude and frequency.

[0507] In some embodiments, the control component generates corresponding noise suppression frames based on the phase, amplitude, and frequency parameters of the frequency domain noise frames. Then, it performs phase reversal (Δφ = π) on each frequency domain noise frame to ensure destructive interference with the original noise. Automatic gain control (AGC) is then used to make the amplitude of the noise suppression frame consistent with that of the frequency domain noise frame (error ≤ 3%). Finally, phase-locked loop (PLL) technology is used to keep the frequency of the noise suppression frame synchronized with that of the frequency domain noise frame (drift ≤ 0.1Hz) to ultimately form a noise suppression frame sequence that corresponds one-to-one with the frequency domain noise frame.

[0508] Step S223: Based on the motor speed and vibration frequency of the drive motor, the airflow speed and number of blades of the portable fan, determine the compensation gain corresponding to each frequency within the target frequency range.

[0509] The target frequency range is the frequency range in which the noise of each motor is located.

[0510] In some embodiments, the control component constructs a dynamic compensation model and calculates the compensation gain within the target frequency range based on multi-parameter fusion. Specifically, this includes: the real-time rotational speed of the input drive motor (acquired by a Hall sensor, range 2000-6000 rpm), vibration frequency (extracted from the signal of a third microphone), airflow speed of the air supply section (converted from the impeller speed), number of fan blades (preset parameter, such as 6 blades), and the target frequency range, such as mechanical vibration noise (500-3000 Hz), electromagnetic noise (1000-5000 Hz), and aerodynamic noise (800-8000 Hz); then, a piecewise function is used for dynamic adjustment. For example, when the motor speed is >4000 rpm, the aerodynamic noise compensation gain is increased by 1.2 times; when the vibration frequency is in the resonant frequency band (1800-2200 Hz), the mechanical vibration noise compensation gain is increased to 1.5 times; finally, the electromagnetic noise compensation gain is positively correlated with the current intensity.

[0511] Step S224: Based on each noise suppression frame and the compensation gain corresponding to each frequency within the target frequency range, noise control commands are generated for mechanical vibration noise, electromagnetic noise, and aerodynamic noise, respectively.

[0512] In some embodiments, the control component integrates the noise suppression frame and the compensation gain to generate dedicated control commands for three types of noise. Specifically, the noise suppression frame is multiplied by the compensation gain and converted into a PWM control signal (frequency 1-10kHz). The processed suppression frame is then converted from a signal to an analog signal (0-3.3V) by a D / A converter. Finally, an audio drive signal (power ≤0.5W) is generated through a digital-to-analog converter to transmit all commands to the noise suppressor via the SPI bus, ensuring real-time performance.

[0513] In other embodiments, the control component may also use an analog-to-digital converter to perform analog-to-digital conversion processing on the motor noise signal of each frame to obtain the corresponding pulse code signal; then, the pulse code signal of each frame is input into the first determining submodule 222 to perform phase inversion processing to obtain the noise suppression frame corresponding to each motor noise.

[0514] In some embodiments, the pulse-coded signal is an audio pulse-code modulation (PCM) signal.

[0515] Specifically, an analog-to-digital converter (ADC) is an electronic device or circuit that converts analog signals into digital signals. This process, called analog-to-digital conversion, aims to enable analog signals to be processed by digital computers or control components.

[0516] Figure 33 is a block diagram of an electronic device 20 provided in an embodiment of this application. For example, the electronic device 20 can be a handheld fan for wireless use, a neck-mounted fan for use, or a strap-on fan for use, etc. Referring to Figure 33, the electronic device 20 includes a processor 21, which can be a processor set, including one or more processors. The electronic device 20 also includes memory resources represented by a memory unit 22, where computer programs, such as application programs, are stored. The computer programs stored in the memory unit 22 can include one or more modules, each corresponding to a set of executable instructions. Furthermore, the processor 21 is configured to implement, when executing the computer program, an active noise cancellation program, an automated signal processing program, and a signal feedback control program as described above.

[0517] In some embodiments, the electronic device 20 is a handheld fan. The computing system within the electronic device 20 can run one or more operating systems, including any operating system and any commercially available server operating system. The electronic device 20 can also run any of a variety of additional server applications and / or middleware applications, including HTTP (Hypertext Transfer Protocol) servers, FTP (File Transfer Protocol) servers, CGI (Common Gateway Interface) servers, super servers, database servers, etc. Exemplary database servers include, but are not limited to, commercially available database servers from companies such as IBM.

[0518] In some embodiments, the processor 21 typically controls the overall operation of the electronic device 20, such as operations associated with display, data processing, data communication, and recording operations. The processor 21 may include one or more processor components to execute a computer program to perform all or part of the steps of the control program described above. Furthermore, the processor component may include one or more modules to facilitate interaction between the processor component and other components. For example, the processor component may include a multimedia module to facilitate control of the interaction between the user electronic device 20 and the processor 21 using multimedia components.

[0519] In some embodiments, the processor component in processor 21 may also be referred to as a CPU (Central Processing Unit). The processor component may be an electronic chip with signal processing capabilities. The processor may also be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. A general-purpose processor may be a microprocessor or any conventional processor component. Furthermore, the processor component may be implemented using integrated circuit chips.

[0520] In some embodiments, memory 22 is configured to store various types of data to support the operation of electronic device 20. Examples of such data include instructions, acquired data, messages, signals, etc., for any application operating on electronic device 20. Memory 22 can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic storage, flash memory, magnetic disk, optical disk, or graphene storage.

[0521] In some embodiments, the memory 22 can be a memory module, TF card, etc., and can store all information in the electronic device 20, including the input raw data, computer programs, intermediate running results, and final running results. In some embodiments, it stores and retrieves information according to the location specified by the processor 21. In some embodiments, the electronic device 20 has a memory function and can ensure normal operation because of the memory 22. In some embodiments, the memory 22 of the electronic device 20 can be classified into main memory (RAM) and auxiliary memory (external memory) according to its purpose, or it can be classified into external memory and internal memory. External memory is usually magnetic media or optical discs, which can store information for a long time. RAM refers to the storage component on the motherboard, which is used to store the currently executing data and programs, but it is only used to temporarily store programs and data. The data will be lost when the power is turned off or disconnected.

[0522] In some embodiments, electronic device 20 may further include: a power supply component 23 configured to perform power management of processor 21, a wired or wireless network interface 24 configured to connect server 20 to a network, and an input / output (I / O) interface 25. Electronic device 20 may operate on an operating system stored in memory 22, such as Windows Server, Mac OS X, Unix, Linux, FreeBSD, or similar.

[0523] In some embodiments, power supply component 23 provides power to various components of electronic device 20. Power supply component 23 may include a power management system, one or more power supplies, and other components associated with generating, managing, and distributing power to electronic device 20.

[0524] In some embodiments, the wired or wireless network interface 24 is configured to facilitate wired or wireless communication between the electronic device 20 and other devices. The electronic device 20 may access wireless networks based on communication standards, such as WiFi, carrier networks (such as 2G, 3G, 4G, or 5G), or combinations thereof.

[0525] In some embodiments, the wired or wireless network interface 24 receives broadcast signals or broadcast-related information from an external broadcast management system via a broadcast channel. In one exemplary embodiment, the wired or wireless network interface 24 also includes a near-field communication (NFC) module to facilitate short-range communication. For example, the NFC module may be implemented based on radio frequency identification (RFID) technology, Infrared Data Association (IrDA) technology, ultra-wideband (UWB) technology, Bluetooth (BT) technology, and other technologies.

[0526] In some embodiments, the input / output (I / O) interface 25 provides an interface between the processor 21 and peripheral interface modules, such as a keyboard, click wheel, buttons, etc. These buttons may include, but are not limited to, a home button, volume buttons, a power button, and a lock button.

[0527] Figure 34 is a block diagram of a computer-readable storage medium 30 provided in an embodiment of this application. The computer-readable storage medium 30 stores a computer program 31, wherein the computer program 31, when executed by the processor 21, implements the active noise reduction program, the automated signal processing program, and the signal feedback control program as described above.

[0528] If the integrated units of the various functional units in the various embodiments of this application are implemented as software functional units and sold or used as independent products, they can be stored in the computer-readable storage medium 30. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. The computer-readable storage medium 30 includes a computer program 31, which includes several instructions to cause a computer device (which may be a personal computer, system server, or network device, etc.), an electronic device (e.g., a handheld electric fan, or a desktop fan, wearable fan, etc.), or a processor to execute all or part of the steps of the methods of the various embodiments of this application.

[0529] Figure 35 is a block diagram of a computer program product 40 provided in an embodiment of this application. The computer program product 40 includes program instructions 41, which can be executed by a processor 21 to implement the active noise reduction program, the automated signal processing program, and the signal feedback control program as described above.

[0530] Those skilled in the art will understand that embodiments of this application may provide active noise cancellation programs, automated signal processing programs and signal feedback control programs, portable active noise cancellation fans 10, electronic devices 20, computer-readable storage media 30, or computer program products 40. Therefore, this application may take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application may take the form of a computer program product 40 embodied on one or more computer program instructions 41 (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0531] This application is described with reference to flowchart illustrations and / or block diagrams of active noise cancellation procedures, automated signal processing procedures and signal feedback control procedures, portable active noise cancellation fan 10, electronic device 20, computer-readable storage medium 30, or computer program product 40 according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by the computer program product 40. These computer program products 40 can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that program instructions 41, executable by the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in one or more flowchart illustrations and / or one or more block diagrams.

[0532] These computer program products 40 may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that program instructions 41 stored in the computer program product 40 produce an article of manufacture including instruction means that implement the functions specified in one or more flowcharts and / or one or more block diagrams.

[0533] These program instructions 41 may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process, thereby providing steps for implementing the functions specified in one or more flowcharts and / or one or more block diagrams.

[0534] It should be noted that the various programs, electronic devices, computer-readable storage media, computer program products, etc. described above according to the embodiments of this application may also include other implementation methods. For specific implementation methods, please refer to the description of the relevant method embodiments, which will not be elaborated here.

[0535] Other embodiments of this disclosure will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This disclosure is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this disclosure are indicated by the claims.

[0536] It should be understood that this disclosure is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this disclosure is limited only by the appended claims.

Claims

1. A portable active noise-canceling fan, characterized in that, The portable active noise-canceling fan includes: The outer casing is a portable housing with a cavity inside and an air inlet and an air outlet that communicate with each other at both ends of the outer casing. A fan assembly, disposed within the cavity, is used to rotate and generate air pressure to draw air in from the air inlet, pass through the cavity, and blow it out from the air outlet. A noise reduction component is disposed within the cavity and is used to collect noise signals inside and outside the cavity in real time when the fan assembly is running, and to issue a noise reduction signal based on the noise signals. The noise signal is a dynamic composite noise signal that includes intake noise, exhaust noise, fan blade noise, and / or motor noise.

2. The portable active noise-canceling fan according to claim 1, characterized in that, The noise reduction component includes: A signal acquisition device is disposed within the cavity and is used to acquire the noise signal in real time during the operation of the fan assembly. A signal processor, disposed within the cavity and electrically connected to the signal acquisition unit, is used to acquire the noise signal and generate a signal generation command based on the noise signal; A signal generator is disposed in the cavity and electrically connected to the signal processor, for acquiring the signal generation command and emitting the noise reduction signal according to the signal generation command; Within a preset error tolerance range, the noise reduction signal and the noise signal are opposite in phase but have the same frequency and amplitude, so as to perform destructive interference on the noise signal and achieve active noise control of the fan assembly.

3. The portable active noise-canceling fan according to claim 2, characterized in that, The signal processor is also used to call a pre-trained noise reduction model to perform noise control processing on the noise signal and obtain noise control instructions; The signal generator is also used to acquire the noise control command and issue the noise reduction signal according to the noise control command to perform active noise control on the portable fan; The noise reduction model includes: A pre-trained classification network, connected to the signal acquisition unit, is used to classify the acquired noise signals to determine the noise scene category in which the portable fan is located; A noise reduction signal database, connected to the classification network, is used to perform signal matching processing on the noise signal based on the noise scene category, determine the target noise reduction signal that matches the noise signal, and generate noise control instructions based on the target noise reduction signal.

4. The portable active noise-canceling fan according to claim 3, characterized in that, Different noise scene categories correspond to a noise reduction signal database, and each noise reduction signal database is used to store noise reduction signals that are opposite in phase but have the same frequency and amplitude as a variety of preset noise signals. The noise reduction model is also used to generate new noise control instructions by calling the stored noise reduction signal database corresponding to the changed noise scene category when the noise scene category changes.

5. The portable active noise-canceling fan according to claim 4, characterized in that, The signal acquisition device includes at least one sound sensor, which is disposed at at least one target point within the cavity, for real-time acquisition of static noise signals near each target point. The target points include at least the edge of the air inlet, the edge of the air outlet, the vicinity of the motor, the vicinity of the fan blades, and the vicinity of the center of the air duct. The intake noise includes static intake noise generated by the portable active noise-canceling fan when used in a fixed position and dynamic intake noise generated when the user shakes the fan. The exhaust noise includes static exhaust noise generated by the portable active noise-canceling fan when used in a fixed position and dynamic exhaust noise generated when the user shakes the fan. The fan blade noise includes static fan blade noise generated by the portable active noise-canceling fan when used in a fixed position and dynamic fan blade noise generated when the user shakes the fan. The motor noise includes static motor noise generated by the portable active noise-canceling fan when used in a fixed position and dynamic fan blade noise generated when the user shakes the fan. And / or, the signal processor includes a filter, a signal synthesizer, a signal amplifier, an analog-to-digital converter, and a computer chip connected in sequence; wherein, the filter is used to perform real-time filtering processing on the noise signals collected by each of the sound sensors to obtain filtered noise signals; the signal synthesizer is used to perform signal fusion processing on each of the filtered noise signals to obtain a dynamically composed composite noise signal; the signal amplifier is used to perform signal amplification processing on the composite noise signal to obtain a composite amplified signal; the analog-to-digital converter is used to perform analog-to-digital conversion processing on the composite amplified signal to obtain a corresponding pulse-coded signal; the computer chip is used to perform phase inversion processing on the pulse-coded signal to obtain inverted signal data, and generate the signal generation command based on the inverted signal data; And / or, the signal generator includes at least one sound player and a power amplifier disposed at each of the target points; wherein, the power amplifier is used to amplify the inverted signal data carried by the signal generation command to obtain a power amplified signal; the sound player is used to emit a noise reduction signal that is opposite in phase and has the same frequency and amplitude as the composite noise signal according to the power amplified signal.

6. The portable active noise-canceling fan according to claim 4, characterized in that, The signal processor further includes an amplitude comparator, the input of which is electrically connected to the analog-to-digital converter, and the output of which is electrically connected to the computer chip. The amplitude comparator is used to acquire the pulse-coded signal and extract a corresponding noise amplitude sequence from the pulse-coded signal, comparing the noise amplitude sequence with a preset amplitude threshold to obtain a first comparison result. The computer chip is also used to acquire the first comparison result, and when the first comparison result indicates that the noise amplitude sequence is greater than the amplitude threshold, to perform phase inversion processing on the pulse-coded signal to obtain the inverted signal data; or, when the first comparison result indicates that the noise amplitude sequence is less than or equal to the amplitude threshold, to terminate the noise reduction process. And / or, the signal processor further includes a decibel comparator, the input of which is electrically connected to the signal acquisition unit, and the output of which is electrically connected to the computer chip; wherein, the decibel comparator is used to acquire the residual noise signal collected in real time by the signal acquisition unit after the signal generator emits the noise reduction signal, and extract the corresponding noise decibel value from the residual noise signal, so as to compare the noise decibel value with a preset decibel threshold to obtain a second comparison result; the computer chip is also used to acquire the second comparison result, and when the second comparison result is that the noise decibel value is greater than the decibel threshold, to reduce the speed of the motor of the fan assembly, or when the second comparison result is that the noise decibel value is less than or equal to the decibel threshold, to end the noise reduction program; And / or, the signal processor further includes an error acquisition element; the error acquisition element is disposed in the cavity and electrically connected to the computer chip, and is used to calculate the error between the noise signal and the noise reduction signal to obtain error signal data, and feed the error signal data back to the computer chip so that the computer chip can perform calibration processing on the noise reduction signal; And / or, the portable active noise-canceling fan further includes a memory disposed within the cavity, for storing a preset speed-to-noise comparison table and a noise-canceling signal database; wherein, the speed-to-noise comparison table is used to characterize the correspondence between the speed of the motor in the fan assembly and the noise signal generated by the fan assembly; the noise-canceling signal database is used to store noise-canceling signals that are opposite in phase but have the same frequency and amplitude as various preset noise signals; the noise-canceling component is also used to acquire the real-time speed of the motor when the fan assembly is running, and determine a target noise signal matching the real-time speed according to the speed-to-noise comparison table, and determine a target noise-canceling signal matching the target noise signal from the noise-canceling signal database, so as to perform active noise control on the fan assembly based on the target noise-canceling signal.

7. The portable active noise-canceling fan according to claim 1, characterized in that, The fan assembly includes a motor and fan blades. The fan blades 220 include a hub and multiple blades spaced around the hub. The motor and a motor noise reduction device are disposed inside the casing of the portable active noise-canceling fan. The motor is a high-speed motor with an operating speed exceeding a preset speed, and the high-speed motor includes a high-speed three-phase micro motor. The motor noise reduction device includes: A noise collector is installed inside the air supply section to collect the motor noise generated by the handheld fan during operation in real time; the motor noise includes the mechanical vibration noise, electromagnetic noise and aerodynamic noise of the motor. A noise processor, disposed on the handheld unit and electrically connected to the noise collector, is used to generate a noise control command based on the motor noise when the signal strength of the motor noise is greater than the strength threshold. A noise suppressor is disposed inside the air supply section and electrically connected to the noise processor. It is used to acquire the noise control command and issue a noise reduction signal according to the noise control command to cancel the interference of the motor noise. The hub includes a conical cavity for covering and fixing the motor.

8. The portable active noise-canceling fan according to claim 7, characterized in that, The noise collector includes: a first microphone disposed on the inner wall of the conical cavity for collecting electromagnetic noise generated by the motor during operation; a second microphone disposed on the outer surface of the hub for collecting aerodynamic noise generated by the motor during operation; and a third microphone disposed on the motor for collecting mechanical vibration noise generated by the motor during operation. And / or, the noise processor includes: a first processing submodule, configured to perform framing, windowing, and time-frequency transformation processing on the mechanical vibration noise, the electromagnetic noise, and the aerodynamic noise respectively, to obtain a plurality of corresponding frequency domain noise frames; a first determining submodule, configured to determine the noise suppression frame corresponding to each of the motor noises, wherein the plurality of noise suppression frames correspond one-to-one with the plurality of frequency domain noise frames, and the corresponding noise suppression frames and frequency domain noise frames have opposite phases, the same amplitude, and the same frequency; a second determining submodule, configured to determine the compensation gain corresponding to each frequency within a target frequency range based on the motor speed and vibration frequency of the motor, the airflow speed of the air supply unit, and the number of fan blades; wherein the target frequency range is the frequency range in which each of the motor noises is located; and a first generating submodule, configured to generate noise control commands for the mechanical vibration noise, the electromagnetic noise, and the aerodynamic noise respectively based on the noise suppression frames and the compensation gain corresponding to each frequency within the target frequency range. And / or, the noise suppressor includes a power amplifier and a sound player; wherein, the power amplifier is used to acquire noise control commands for the mechanical vibration noise, the electromagnetic noise and the aerodynamic noise respectively, and amplify the noise reduction data carried by the various noise control commands to obtain corresponding power amplification signals; the sound player is used to emit noise reduction signals that are opposite in phase and have the same frequency and amplitude as the various motor noises according to the power amplification signals.

9. The portable active noise-canceling fan according to claim 8, characterized in that, The audio player includes: A first player is disposed on the inner wall of the conical cavity and corresponds to the first microphone, used to acquire a power amplified signal for the electromagnetic noise in order to play the first noise-reduced signal; A second player is disposed on the outer surface of the hub and corresponds to the second microphone, for acquiring a power amplified signal for the aerodynamic noise in order to play the second noise-reduced signal; A third player, mounted on the motor and corresponding to the third microphone, is used to acquire a power-amplified signal for the mechanical vibration noise in order to play a third noise-reduced signal.

10. The portable active noise-canceling fan according to claim 7, characterized in that, The hub has an annular sidewall for accommodating the high-speed three-phase micro motor; the multiple blades include a blade root and a blade tip, and each blade is connected to the outer surface of the annular sidewall through the blade root and is spaced apart along its circumference. Among them, each blade is provided with an arc-shaped protruding blade tip wing, and the blade tip wing is inclined at a preset angle with the axial direction of the hub, so as to reduce the aerodynamic noise generated by the leakage of airflow at the blade tip when the high-speed three-phase micro motor drives the fan blade to rotate. And / or, the blade tip winglet is tilted outward at an angle of 10° to 30° with respect to the axial direction of the hub, and a rounded transition with a radius of 3mm to 7mm is provided at the root of the blade tip winglet and the blade tip.

11. The portable active noise-canceling fan according to claim 10, characterized in that, Each of the blades further includes a leading edge wing and a trailing edge wing; the first end of the leading edge wing is connected to the first end of the leaf root, and the second end of the leading edge wing is connected to the first end of the leaf tail, and the first end of the trailing edge wing is connected to the second end of the leaf root, and the second end of the trailing edge wing is connected to the second end of the leaf tail, so as to form a closed blade shape. Wherein, the leading edge wing is located on the front side in the direction of rotation, the trailing edge wing is located on the rear side in the direction of rotation, and in the axial direction of the hub, the leading edge wing is located above the trailing edge wing; And / or, the blade tip winglet extends from the trailing edge wing to the leading edge wing in the direction of rotation, and the ratio of the length of the blade tip winglet to the length of the blade tip is 3:4 or 4:5; And / or, the thickness of each blade and the blade tip winglet increases to a maximum thickness from the trailing edge wing in the direction of rotation, and decreases from the maximum thickness towards the leading edge wing, so as to form a blade and a convex blade tip winglet that are arc-shaped at the blade tip. And / or, the ratio of the maximum thickness of each blade to the maximum thickness of the blade tip winglet is 1:0.9, and the ratio of the maximum thickness of each blade to the width of the blade tip winglet is 0.9:1; And / or, the leaf roots of each blade are connected in a counterclockwise bend along the surface of the annular sidewall from the top edge of the annular sidewall to the bottom edge, and each blade has a radially extending twisted shape from the leaf root to the leaf tip.

12. The portable active noise-canceling fan according to claim 11, characterized in that, Each blade includes a suction surface and a pressure surface arranged opposite to each other; In the axial direction of the hub, the suction surface is located above the pressure surface; And / or, the suction surface is raised to form an outer arc shape to reduce the wind resistance of the blades when rotating, and the pressure surface is concave to form an inner arc shape to guide the airflow.

13. The portable active noise-canceling fan as described in any one of claims 1 to 12, characterized in that, The portable active noise-canceling fan includes at least a handheld fan for wireless use, a neck-hanging fan for use around the neck, or a strap-on fan for use in a strap-on manner.

14. An active noise reduction method for a portable fan, characterized in that, The method includes: Acquire noise signals; the noise signals are dynamic composite noise signals generated by the portable fan during operation, including intake noise, exhaust noise, fan blade noise and / or motor noise; The noise signal is processed by a pre-trained noise reduction model to obtain noise control instructions. Based on the noise control command, a noise reduction signal is issued to actively control the noise of the portable fan; wherein, within a preset error allowable range, the noise reduction signal is opposite in phase and has the same frequency and amplitude as the noise signal, and is used to perform destructive interference on the noise signal.

15. The active noise reduction method according to claim 14, characterized in that, The pre-trained noise reduction model performs noise control processing on the noise signal to obtain noise control instructions, including: The noise signal is classified based on a pre-trained classification network to determine the noise scene category in which the portable fan is located; Based on the noise scene category, the corresponding noise reduction signal database is invoked to perform signal matching processing on the noise signal, determine the target noise reduction signal that matches the noise signal, and generate a noise control command based on the target noise reduction signal; Each of the noise scene categories corresponds to a noise reduction signal database, and each of the noise reduction signal databases is used to store noise reduction signals that are opposite in phase but have the same frequency and amplitude as a variety of preset noise signals. The noise reduction model is also used to determine whether the noise scene category has changed based on the input noise signal, and if the noise scene category has changed, it calls the stored noise reduction signal database corresponding to the changed noise scene category to generate a new noise control command.

16. The active noise reduction method according to claim 15, characterized in that, The noise control processing of the noise signal based on the pre-trained noise reduction model to obtain noise control instructions further includes: The noise amplitude sequence is extracted from the noise signal, and the noise amplitude sequence is compared with a preset amplitude threshold to obtain the evaluation result. When the evaluation result indicates that the noise amplitude sequence is greater than the amplitude threshold, the noise signal is phase-inverted based on the noise reduction model to obtain inverted signal data, and the noise control command is generated based on the inverted signal data; or, when the evaluation result indicates that the noise amplitude sequence is less than or equal to the amplitude threshold, the active noise control program is terminated.

17. The active noise reduction method according to claim 16, characterized in that, The step of extracting the noise amplitude sequence from the noise signal includes performing real-time filtering on the noise signal to obtain a filtered noise signal; performing signal fusion on the filtered noise signal to obtain a dynamically composed composite noise signal; and performing signal amplification on the composite noise signal to obtain a composite amplified signal. The amplified signal is subjected to analog-to-digital conversion to obtain a corresponding pulse-coded signal, and the noise amplitude sequence is extracted from the pulse-coded signal. And / or, the acquisition of noise signals includes, in response to the operation of the portable fan, real-time acquisition of the dynamic composite noise signal based on a signal acquisition device disposed in the portable fan; wherein, the intake noise in the dynamic composite noise signal includes the static intake noise generated by the active noise-canceling fan when used in a fixed position and the dynamic intake noise generated by the user shaking the fan; the exhaust noise includes the static exhaust noise generated by the active noise-canceling fan when used in a fixed position and the dynamic exhaust noise generated by the user shaking the fan; the fan blade noise includes the static fan blade noise generated by the active noise-canceling fan when used in a fixed position and the dynamic fan blade noise generated by the user shaking the fan; and the motor noise includes the static motor noise generated by the active noise-canceling fan when used in a fixed position and the dynamic fan blade noise generated by the user shaking the fan. And / or, the signal acquisition device is disposed within the internal cavity of the portable fan, and the signal acquisition device includes at least one sound sensor, and the at least one sound sensor is disposed at at least one target point corresponding to the cavity; the real-time acquisition of the dynamic composite noise signal based on the signal acquisition device disposed in the portable fan includes: real-time acquisition of the dynamic composite noise signal near each of the target points based on the at least one sound sensor; wherein, the target points include at least the edge position of the air inlet of the portable fan, the edge position of the air outlet, the position near the motor, the position near the fan blades, and the position near the center of the air duct.

18. The active noise reduction method according to claim 17, characterized in that, The step of issuing a noise reduction signal based on the noise control command to actively control the noise of the portable fan includes: The target noise reduction signal or inverted signal data carried in the noise control command is amplified to obtain a power amplified signal. Based on the power amplification signal, a noise reduction signal with the opposite phase, frequency, and amplitude to the noise signal is emitted at each of the target points to perform destructive interference on the noise signal.

19. The active noise reduction method according to claim 18, characterized in that, A drive motor is installed inside the portable fan; the active noise reduction method further includes: The motor noise generated by the portable fan during operation is obtained; the motor noise includes the mechanical vibration noise, electromagnetic noise, and aerodynamic noise of the drive motor; When the signal strength of the motor noise is greater than a preset strength threshold, a noise control command is generated based on the motor noise. Based on the noise control command, noise reduction signals are generated and emitted for the mechanical vibration noise, the electromagnetic noise and the aerodynamic noise, respectively, so as to perform destructive interference on the motor noise.

20. The active noise reduction method according to claim 19, characterized in that, The noise control command generated based on the motor noise includes: The mechanical vibration noise, the electromagnetic noise, and the aerodynamic noise are respectively processed by framing, windowing, and time-frequency transformation to obtain multiple corresponding frequency domain noise frames; Determine the noise suppression frame corresponding to each of the motor noises; the plurality of noise suppression frames correspond one-to-one with the plurality of frequency domain noise frames, and the corresponding noise suppression frames and frequency domain noise frames have opposite phases, the same amplitude and frequency; Based on the motor speed and vibration frequency of the drive motor, the airflow speed and number of blades of the portable fan, the compensation gain corresponding to each frequency within the target frequency range is determined; the target frequency range is the frequency range in which the noise of each motor is located. Based on each noise suppression frame and the compensation gain corresponding to each frequency within the target frequency range, noise control commands are generated for the mechanical vibration noise, the electromagnetic noise, and the aerodynamic noise, respectively.

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