Range hood noise reduction method, range hood and intelligent kitchen system

Abstract

The invention provides a range hood noise reduction method, a range hood and a smart kitchen system, and relates to the technical field of smart kitchens. The range hood comprises: a tunable Helmholtz resonant cavity; the tunable Helmholtz resonant cavity is internally provided with a resonance space with an adjustable size, and the resonance space is communicated with an air duct of the range hood; the method comprises the steps of obtaining the rotating speed of the range hood in response to change of the working state of the range hood; determining target parameters of the tunable Helmholtz resonant cavity based on a preset rotating speed-resonant cavity parameter mapping table; adjusting the volume of a resonance space in the tunable Helmholtz resonant cavity based on the target parameter; by detecting the rotating speed of the draught fan in real time and adjusting the volume of the resonant cavity based on the preset mapping table, the resonant frequency is matched with the main noise frequency under the current working condition in a self-adaptive mode, real-time tracking and effective suppression of noise of different gears are achieved, the defect that the frequency of a traditional passive resonant cavity is fixed is overcome, and the noise suppression efficiency is improved. And the noise reduction effect and the user experience under all working conditions are obviously improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of smart kitchen, and in particular to an oil fume exhaust fan noise reduction method, an oil fume exhaust fan and a smart kitchen system. BACKGROUND

[0002] The operation noise of the oil fume exhaust fan mainly comes from the low-frequency periodic noise generated by the rotation of the fan impeller, the broadband noise caused by the airflow vortex and turbulence in the air duct, and the secondary noise radiated by the structure resonance.

[0003] To suppress the noise, the traditional method usually adopts a passive Helmholtz resonance cavity with fixed parameters or increases the sound insulation cotton. However, the sound insulation cotton has limited effect on low-frequency noise absorption and is easy to accumulate oil stains; while the passive resonance cavity can absorb specific frequencies, but its resonance frequency is fixed and cannot follow the shift of the main noise frequency caused by the user switching gears (i.e. the change of fan speed), so the noise reduction effect is unstable in the actual multi-gear use scene, and the practicability and adaptability are poor. SUMMARY

[0004] The present application aims to provide an oil fume exhaust fan noise reduction method, an oil fume exhaust fan and a smart kitchen system, which can detect the fan speed in real time and adjust the resonance cavity volume based on a preset mapping table, so that the resonance frequency can be adaptively matched with the main noise frequency under the current working condition, realizing real-time tracking and effective suppression of noise under different gears, overcoming the defect of fixed frequency of the traditional passive resonance cavity, and significantly improving the noise reduction effect and user experience under all working conditions.

[0005] In the first aspect, the present application provides an oil fume exhaust fan noise reduction method applied to an oil fume exhaust fan controller; the oil fume exhaust fan comprises: a tunable Helmholtz resonance cavity; the tunable Helmholtz resonance cavity has a resonance space with adjustable size, and the resonance space is in communication with the air duct of the oil fume exhaust fan; the method comprises: In response to the change of the working state of the oil fume exhaust fan, the speed of the oil fume exhaust fan is obtained; Based on a preset speed-resonance cavity parameter mapping table, the target parameters of the tunable Helmholtz resonance cavity are determined; Based on the target parameters, the volume of the resonance space in the tunable Helmholtz resonance cavity is adjusted, so that the resonance frequency of the tunable Helmholtz resonance cavity matches the main noise frequency under the current speed, realizing adaptive noise reduction.

[0006] In some preferred embodiments of the present application, the tunable Helmholtz resonance cavity comprises: a movable valve plate and a displacement mechanism; one side of the movable valve plate is connected with the displacement mechanism, and the other side forms a resonance space with the side wall of the tunable Helmholtz resonance cavity; the target parameters comprise: target current parameters; based on the target parameters, the volume of the resonance space in the tunable Helmholtz resonance cavity is adjusted, comprising: Adjust the state of the displacement mechanism based on the target current parameter, so that the movable valve plate moves in the tunable Helmholtz resonator, thereby changing the volume of the resonance space.

[0007] In some preferred embodiments of the present application, the displacement mechanism comprises: a piezoelectric ceramic, a shape memory alloy spring or a stepper motor.

[0008] In some preferred embodiments of the present application, the tunable Helmholtz resonator further comprises: a rigid cavity base; the rigid cavity base is made of a rigid, acoustically inert material; the rigid cavity base has a neck structure; the rigid cavity base is in communication with the air duct of the range hood through the neck structure; the movable valve plate is made of a flexible composite material.

[0009] In some preferred embodiments of the present application, after the step of adjusting the volume of the resonance space in the tunable Helmholtz resonator based on the target parameter, the method further comprises: Acoustically sampling the range hood to obtain current noise data; Judging whether the current noise data meets the preset noise reduction condition; If not, adjusting the target parameter based on the preset gradient descent fine-tuning algorithm to adjust the noise, and after multiple iterations of adjustment, determining the optimal target parameter; Updating the speed-resonance cavity parameter mapping table based on the optimal target parameter.

[0010] In some preferred embodiments of the present application, the speed-resonance cavity parameter mapping table comprises: original noise data corresponding to the state of the range hood; the noise reduction condition comprises: reducing the sound pressure level of the preset target value; the step of judging whether the current noise data meets the preset noise reduction condition comprises: Determining the original noise data corresponding to the current state of the range hood in the speed-resonance cavity parameter mapping table; Judging whether the sound pressure level difference between the original noise data and the current noise data meets the target value.

[0011] In some preferred embodiments of the present application, before the step of obtaining the speed of the range hood in response to the change of the working state of the range hood, the method further comprises: In response to the control signal, gradually adjusting the working state of the range hood from the lowest gear to the highest gear; collecting corresponding noise data at each preset speed collection point during the gear adjustment, and gradually changing the size of the resonance space at each speed collection point, and determining the target parameter corresponding to the speed collection point through the noise reduction effect; Based on the speed, noise data and target parameter corresponding to the speed collection point, generating a speed-resonance cavity parameter mapping table.

[0012] In some preferred embodiments of the present application, the air duct of the range hood is an air duct designed based on topology optimization; the air duct is determined by the following steps: A basic air duct is generated by a preset topology optimization algorithm to minimize flow resistance and optimize acoustic performance as the goal; Based on the basic air duct and the tunable Helmholtz resonator corresponding to the multiple target parameters, multiple over-air ducts are constructed; The multiple air ducts are jointly optimized by the topology optimization algorithm to minimize flow loss as the goal, and the air duct of the range hood is obtained.

[0013] In a second aspect, the present application provides a range hood, comprising: a tunable Helmholtz resonator and a range hood controller; the tunable Helmholtz resonator has a resonant space with adjustable size, and the resonant space is in communication with the air duct of the range hood; the air duct is an air duct designed based on topology optimization; the range hood controller is used to execute the range hood noise reduction method provided in the first aspect.

[0014] In a third aspect, the present application provides a smart kitchen system, comprising: the range hood provided in the second aspect.

[0015] The present application has the following beneficial effects: The present application provides a range hood noise reduction method, a range hood and a smart kitchen system, which are applied to a range hood controller; the range hood comprises: a tunable Helmholtz resonator; the tunable Helmholtz resonator has a resonant space with adjustable size, and the resonant space is in communication with the air duct of the range hood; the method comprises: in response to a change in the working state of the range hood, obtaining the rotating speed of the range hood; determining the target parameter of the tunable Helmholtz resonator based on a preset rotating speed-resonator parameter mapping table; adjusting the volume of the resonant space in the tunable Helmholtz resonator based on the target parameter, so that the resonant frequency of the tunable Helmholtz resonator matches the main noise frequency under the current rotating speed, realizing adaptive noise reduction; by detecting the rotating speed of the fan in real time and adjusting the volume of the resonator based on the preset mapping table, the resonant frequency is adaptively matched with the main noise frequency under the current working condition, realizing real-time tracking and effective suppression of noise at different gears, overcoming the defect of fixed frequency of the traditional passive resonator, and significantly improving the noise reduction effect and user experience under all working conditions. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the drawings needed to be used in the description of the specific embodiments or the prior art. Obviously, the drawings described below are some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0017] Figure 1A flowchart of a noise reduction method for a range hood provided in an embodiment of the present invention; Figure 2 A cross-sectional view of a tunable Helmholtz resonator with a shape memory alloy spring provided in an embodiment of the present invention; Figure 3 A schematic diagram of the topology of a tunable Helmholtz resonator provided in an embodiment of the present invention; Figure 4 A schematic diagram of a topology-optimized range hood provided in an embodiment of the present invention; Figure 5 A schematic diagram of a topological flow channel provided in an embodiment of the present invention; Figure 6 This is a schematic diagram of the assembly position of a topology flow channel provided in an embodiment of the present invention; Figure 7 A flowchart of another noise reduction method for a range hood provided in an embodiment of the present invention.

[0018] Icons: 1-Modible valve plate; 2-Shape memory alloy spring; 3-Rigid cavity base; 4-Air duct wall; 5-Position of tunable Helmholtz resonant cavity; 6-Range hood; 7-Topological flow channel. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0020] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0021] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0022] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. In addition, the terms "first," "second," "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0023] Furthermore, terms such as "horizontal," "vertical," and "sag" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0024] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0025] The noise reduction principle of a Helmholtz resonator can be summarized into two core physical processes: (1) resonant absorption and energy dissipation; (2) acoustic impedance mismatch and reflection. These can be explained in detail as follows: Step 1: Capture a specific frequency (resonance).

[0026] When the frequency of the sound waves transmitted from the outside matches the natural frequency of the resonant cavity, a strong resonance will be triggered.

[0027] This natural frequency f0 can be calculated using the following formula: ; Where: c is the speed of sound (approximately 340 m / s in air). S is the cross-sectional area of ​​the neck. V is the volume of the cavity. Leff is the effective length of the neck (actual physical length plus a correction value for the opening).

[0028] This means that by designing the cavity volume V, neck area S, and length Leff, we can tune the resonant cavity specifically for a particular noise frequency that we want to eliminate (e.g., a low-frequency hum at 100Hz).

[0029] Step 2: Air piston vibration and friction generate heat (energy conversion).

[0030] When resonance occurs, the air column in the neck acts like a small piston, vibrating back and forth at high speed and violently under the drive of sound pressure.

[0031] As these air molecules move within the narrow neck opening, they experience extremely intense friction and adhesion with the neck wall and themselves.

[0032] This friction process converts the ordered mechanical kinetic energy carried by the sound waves into disordered thermal energy.

[0033] Simply put, the energy of sound is "ground" into heat and eventually dissipates. This is the core noise reduction mechanism.

[0034] Step 3: Acoustic impedance cancels out phase (reflection).

[0035] Near the resonant frequency, the resonant cavity exhibits extremely high acoustic impedance to sound waves, which can be understood as the "resistance" to sound wave propagation becoming very large.

[0036] When a sound wave encounters such a high-impedance interface, it has difficulty continuing to propagate forward, and most of its energy is reflected back.

[0037] The reflected sound wave encounters the original incident sound wave near the resonant cavity opening. If their phases are opposite (180 degrees apart), destructive interference will occur, resulting in a significant reduction in the sound wave amplitude (i.e., volume) at that location.

[0038] In summary, a specific frequency component in the external noise "excites" the resonant cavity → the air in the neck vibrates violently like a piston → the vibration energy is converted into heat energy through air friction → at the same time, the resonant cavity generates high impedance to the sound wave, reflects the sound wave and causes destructive interference with the incident wave → ultimately, the noise at this specific frequency is significantly weakened.

[0039] Based on this, this application sets a Helmholtz resonant cavity on the duct wall of the range hood 6 and combines it with a unique control method to achieve real-time noise reduction of the range hood 6.

[0040] The following detailed description of some embodiments of the present invention is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0041] Example 1 This invention provides a noise reduction method for a range hood, applied to a range hood controller; the range hood 6 includes: a tunable Helmholtz resonant cavity; the tunable Helmholtz resonant cavity has an adjustable resonant space, and the resonant space is connected to the air duct of the range hood 6.

[0042] Specifically, this tuned Helmholtz resonant cavity is not a simple rigid cavity, but a precision acoustic device integrating a flexible deformable unit and a smart material actuator, which is loaded onto the topological drag-reducing flow channel structure of the range hood 6. The flexible deformable unit can be any wall of the cavity, and the actuator is connected to the flexible deformable unit, causing the flexible deformable unit to deform and thus change the volume of the cavity.

[0043] It should be noted that the fixed volume portion constituting the resonant cavity can be cylindrical, rectangular, or other shapes that are easy to manufacture and integrate; this embodiment does not specify such a shape.

[0044] See Figure 1 The flowchart shown in this embodiment of the invention provides a method for reducing noise in a range hood, the method comprising: Step S102, Begin.

[0045] Specifically, the range hood 6 is in standby or in a stable state at a certain setting, waiting for user operation or receiving signals from linked devices.

[0046] Step S104: In response to the change in the working state of the range hood 6, the rotation speed of the range hood 6 is obtained.

[0047] Specifically, the fan speed changes according to the amount of oil fume, and its rotational noise frequency is directly related to the speed. In some preferred embodiments of the present invention, a speed sensor installed on the fan motor collects the speed signal in real time. This signal is the most direct and reliable basis for identifying the current main noise frequency, providing accurate operating condition input for subsequent tuning of the resonant cavity, thereby achieving real-time tracking of the noise frequency.

[0048] Furthermore, in some preferred embodiments of the present invention, before the step of obtaining the rotation speed of the range hood 6 in response to a change in the operating state of the range hood 6, the method further includes: in response to a control signal, gradually adjusting the operating state of the range hood 6 from the lowest level to the highest level; during the level adjustment, collecting corresponding noise data at each preset rotation speed acquisition point, and gradually changing the size of the resonance space at each rotation speed acquisition point, determining the target parameter corresponding to the rotation speed acquisition point through noise reduction effect; and generating a rotation speed-resonance cavity parameter mapping table based on the rotation speed, noise data, and target parameter mapping corresponding to the rotation speed acquisition point.

[0049] Specifically, the controller of range hood 6 has a self-learning mode. This mode includes: the controller gradually controls the fan from low speed to high speed, collecting the noise spectrum through a microphone at each speed point, identifying the main noise frequency, and automatically searching for the resonant cavity parameters that minimize the noise amplitude at that frequency. Through traversal and optimization, a complete speed-resonant cavity parameter mapping table is established as the basis for subsequent real-time control, enabling the system to have optimal noise reduction performance from startup and reducing reliance on manual adjustments.

[0050] Step S106: Determine the target parameters of the tunable Helmholtz resonator based on the preset rotational speed-resonance cavity parameter mapping table.

[0051] Specifically, a speed-frequency-resonant cavity parameter mapping table is established during the initialization or self-learning phase. The table records the optimal resonant cavity adjustment parameters (such as target current, target volume, etc.) corresponding to different speeds. In actual operation, the controller queries this table based on the real-time speed to directly obtain the corresponding target parameters, realizing feedforward rapid pre-adjustment. This avoids the defect of traditional passive resonant cavities that cannot adapt to speed changes due to fixed frequency, significantly improving response speed and noise reduction targeting.

[0052] Step S108: Adjust the volume of the resonant space in the tunable Helmholtz resonator based on the target parameters so that the resonant frequency of the tunable Helmholtz resonator matches the main noise frequency at the current rotation speed, thereby achieving adaptive noise reduction.

[0053] Specifically, the resonant frequency of a Helmholtz resonator depends on parameters such as its cavity volume and neck size. By adjusting the cavity volume, its natural frequency can be changed. In this embodiment of the invention, a displacement mechanism is driven according to the target parameters, causing the movable valve plate 1 to shift, thereby precisely changing the volume of the resonant space. This aligns the peak absorption frequency of the resonant cavity with the impeller's passing frequency at the current rotational speed, achieving active absorption and suppression of noise at that frequency, and directly reducing low-frequency rotational noise along the acoustic path.

[0054] Furthermore, in some preferred embodiments of the present invention, the displacement mechanism includes: piezoelectric ceramic, shape memory alloy spring 2, or stepper motor.

[0055] Specifically, piezoelectric ceramics offer advantages such as fast response and high positioning accuracy, making them suitable for high-frequency fine-tuning; shape memory alloy springs 2 can be controlled by current to extend and retract, resulting in a large output displacement, making them suitable for wide-range frequency modulation; and stepper motors possess excellent reliability and stroke control capabilities. Depending on actual cost, space, and frequency adjustment range requirements, different actuators can be selected, all of which can achieve continuous adjustment of the resonant cavity volume, ensuring the system's feasibility and flexibility in various product configurations.

[0056] Furthermore, in some preferred embodiments of the present invention, the tunable Helmholtz resonant cavity further includes: a rigid cavity base 3; the rigid cavity base 3 is made of a rigid, acoustically inert material; the rigid cavity base 3 has a neck structure; the rigid cavity base 3 is connected to the air duct of the range hood 6 through the neck structure; and the movable valve plate 1 is made of a flexible composite material.

[0057] Specifically, the rigid cavity base 3 is typically made of ABS engineering plastic, aluminum, or stainless steel to ensure that the cavity's natural vibration frequency is much higher than the target vibration suppression frequency band, avoiding unnecessary structural modal coupling. The neck, as an acoustic coupling channel, directly affects the resonant frequency due to its cross-sectional area and length. The movable valve plate 1 is made of flexible material, capable of deforming with drive while possessing good sealing performance and durability. This combined design ensures acoustic performance while also considering structural strength and service life.

[0058] Furthermore, in some preferred embodiments of the present invention, the connection between the movable valve plate 1 and the rigid cavity base 3 is permanently sealed by laser welding or high-strength sealant. At the connection between the neck and the main air duct, a removable and easy-to-clean oil-proof filter can be designed, the flow area of ​​which has been precisely calculated and incorporated into the initial design value of the equivalent cross-sectional area S of the resonant cavity.

[0059] Step S110, End.

[0060] Specifically, the system continuously runs the aforementioned monitoring. Once a change in rotational speed is detected, it immediately jumps back to step S106 to begin a new control cycle.

[0061] For example, see Figure 2 The illustrated embodiment of the present invention provides a cross-sectional view of a tunable Helmholtz resonant cavity with a shape memory alloy spring. One side of the movable valve plate 1 is connected to the shape memory alloy spring 2, and the other side forms a tunable Helmholtz resonant cavity with a variable volume by connecting the inner wall of the cavity and the air duct wall 4.

[0062] Further, see Figure 3 The diagram shown is a topological structure of a tunable Helmholtz resonator provided by an embodiment of the present invention. The position 5 of the tunable Helmholtz resonator is located directly opposite the center of the wind turbine.

[0063] Furthermore, the other end of the shape memory alloy spring 2 is connected to a control current i. The movable valve plate 1, serving as the bottom surface of the Helmholtz resonant cavity, can move up and down following the shape memory alloy spring 2. Because of the presence of the movable valve plate 1, the volume V within the Helmholtz resonant cavity can be adjusted, thereby enabling adjustable noise reduction frequency. That is, by adjusting the control current i to control the spring deformation ΔL, the volume V of the Helmholtz resonant cavity is controlled, ultimately adjusting the noise reduction frequency. This design allows for a sufficiently large range of cavity volume variation ΔV, covering a wider range of noise reduction frequency adjustment.

[0064] Furthermore, in some preferred embodiments of the present invention, the tunable Helmholtz resonant cavity includes: a movable valve plate 1 and a displacement mechanism; one side of the movable valve plate 1 is connected to the displacement mechanism, and the other side forms a resonant space with the sidewall of the tunable Helmholtz resonant cavity; the target parameter includes: a target current parameter; the step of adjusting the volume of the resonant space in the tunable Helmholtz resonant cavity based on the target parameter includes: adjusting the state of the displacement mechanism based on the target current parameter so that the movable valve plate 1 moves in the tunable Helmholtz resonant cavity, thereby changing the volume of the resonant space.

[0065] Specifically, the movable valve plate 1 serves as the moving wall of the resonant cavity. Its material can be a flexible composite material (such as polyimide film, silicone rubber film, or thin stainless steel sheet), possessing high fatigue life, good elastic recovery force, oil resistance, and temperature resistance. Furthermore, its own vibration mode must be significantly higher than the operating frequency band. The displacement mechanism receives current signals from the controller and drives the valve plate displacement through the deformation of the shape memory alloy spring 2 or the piezoelectric ceramic stack, thereby continuously and precisely adjusting the effective volume of the cavity. This structure achieves electrically adjustable resonant frequency, enabling the system to dynamically reduce noise following changes in rotational speed.

[0066] Furthermore, in some preferred embodiments of the present invention, after the step of adjusting the volume of the resonant space within the tunable Helmholtz resonant cavity based on the target parameters, the method further includes: performing acoustic sampling on the range hood 6 to obtain current noise data; determining whether the current noise data meets the preset noise reduction conditions; if not, adjusting the target parameters based on a preset gradient descent fine-tuning algorithm to adjust the noise, and determining the optimal target parameters after multiple iterations; and updating the rotational speed-resonant cavity parameter mapping table based on the optimal target parameters.

[0067] Specifically, after feedforward adjustment, the system samples and performs spectral analysis on the actual noise reduction effect using an oil-resistant MEMS microphone. If the target frequency sound pressure level does not reach the preset threshold, a gradient descent fine-tuning algorithm is activated, applying small-step perturbations near the current position and iteratively searching for the optimal parameter point based on the direction of noise change. This mechanism can compensate for system drift caused by oil accumulation, temperature changes, and component aging, ensuring long-term stability of the noise reduction effect and providing adaptive maintenance capabilities.

[0068] Furthermore, in some preferred embodiments of the present invention, the rotation speed-resonance cavity parameter mapping table includes: the original noise data corresponding to the state of the range hood 6; the noise reduction condition includes: reducing the sound pressure level of a preset target value; the step of determining whether the current noise data meets the preset noise reduction condition includes: determining the original noise data corresponding to the current state of the range hood 6 in the rotation speed-resonance cavity parameter mapping table; and determining whether the sound pressure level difference between the original noise data and the current noise data meets the target value.

[0069] Specifically, the aforementioned self-learning phase records not only the adjustment parameters but also the reference noise spectrum at each rotational speed. During feedback evaluation, the noise reduction effect can be quantified by comparing the sound pressure level difference between the current noise and the reference noise at the target frequency. For example, if the difference is greater than 15 dB, the vibration suppression effect is considered satisfactory. This method provides an objective basis for control decisions, improving the reliability and consistency of the system.

[0070] Furthermore, in some preferred embodiments of the present invention, the air duct of the range hood 6 is an air duct based on topology optimization design; the air duct is determined by the following steps: a basic air duct is generated by using a preset topology optimization algorithm with the goal of minimizing flow resistance and optimizing acoustic performance; multiple transition air ducts are constructed based on the basic air duct and tunable Helmholtz resonators corresponding to multiple target parameters; and the air duct of the range hood is obtained by performing joint optimization of multiple air ducts with the goal of minimizing flow loss using a topology optimization algorithm.

[0071] Specifically, the steps for determining the air duct are as follows: First, a basic air duct structure is generated using a preset topology optimization algorithm, with minimizing flow resistance (total pressure loss) as the core objective while also considering broadband acoustic performance (such as propagation loss within a specific frequency band). Then, based on the flow field characteristics and spatial layout of this basic air duct, multiple tunable Helmholtz resonators targeting different target noise frequencies are integrated to construct a series of "transitional air duct" variants integrating tunable Helmholtz resonators. Finally, with minimizing the flow loss of the range hood as the core objective, a "multi-air duct joint optimization" is performed using a topology optimization algorithm, ultimately obtaining a range hood air duct that achieves the optimal balance in both aerodynamics and acoustic performance.

[0072] This optimization process uses the flow channel region as the design domain, with the core objective function being to minimize the total pressure loss (i.e., maximize the total pressure efficiency). Maximizing acoustic propagation loss or acoustic impedance matching within a specific frequency band (e.g., 100-500Hz) can be used as secondary objectives. Constraints include fluid domain volume fraction and manufacturing process requirements (e.g., minimum wall thickness). The final optimized structure is a highly streamlined, multi-path fusion biomimetic topological flow channel 7 structure. This structure significantly reduces airflow separation and eddies, suppresses broadband turbulent noise at its source, and provides a stable and efficient basic flow field environment for subsequent acoustic control of the resonant cavity.

[0073] For example, see Figure 4 The diagram shown is a topology-optimized range hood according to an embodiment of the present invention. Figure 5 The diagram shown is a schematic representation of a basic air duct provided by an embodiment of the present invention. Figure 6 The diagram shown is a schematic representation of a duct assembly location according to an embodiment of the present invention. In the first round of topology optimization, minimizing the total pressure drop from the inlet to the outlet was the objective, resulting in a low-resistance basic biomimetic flow channel (such as...). Figure 5(The basic air duct shape is shown). Subsequently, targeting the two main noise peaks of the range hood around 300Hz and 450Hz, two tunable Helmholtz resonators were designed and integrated, thus forming two preliminary "transitional air duct" schemes. In the final joint optimization stage, the basic air duct and the two air duct variants integrating resonators were used together as design inputs, with the goal of minimizing the overall flow energy loss of the range hood, to perform topology optimization calculations. The optimization algorithm automatically weighed factors such as the air duct shape and resonator layout, and the disturbance of the main flow field by the cavity openings, ultimately generating the final topology air duct structure 7. This structure also further optimized the tunable Helmholtz resonators, updating the parameters of the optimized tunable Helmholtz resonators to the speed-resonator parameter mapping table.

[0074] In some preferred embodiments of the present invention, an "intermediate air duct" can be reconstructed based on the optimized tunable Helmholtz resonator combined with the basic air duct, and multiple rounds of topology optimization can be performed until the parameter variation of the tunable Helmholtz resonator is less than a preset value.

[0075] The air duct, after at least one round of optimization, not only maintains excellent airflow guidance and low resistance characteristics, but also optimizes the integration position and shape of its resonant cavity, achieving the best combination of flow field performance and target frequency band sound absorption efficiency. Furthermore, the tunable Helmholtz resonant cavity in the "final air duct," which is usually obtained through joint optimization of multiple "transitional air ducts," has a smaller adjustment range between multiple operating conditions, allowing for faster response and adjustment, achieving the shortest noise reduction response time, and improving the user experience.

[0076] The resulting air duct is a non-intuitive, streamlined, multi-path fusion biomimetic topology. It effectively guides airflow, avoids eddies and separation, thereby reducing broadband turbulent noise at its source. Through optimized resonant cavity integration design, it achieves precise and rapid noise control, achieving a dual improvement in energy saving and noise reduction.

[0077] This invention provides a noise reduction method for a range hood, applied to a range hood controller. The range hood 6 includes a tunable Helmholtz resonant cavity; the tunable Helmholtz resonant cavity has an adjustable-sized resonant space, which is connected to the air duct of the range hood 6. The method includes: obtaining the rotational speed of the range hood 6 in response to a change in its operating state; determining the target parameters of the tunable Helmholtz resonant cavity based on a preset rotational speed-resonant cavity parameter mapping table; adjusting the volume of the resonant space within the tunable Helmholtz resonant cavity based on the target parameters, so that the resonant frequency of the tunable Helmholtz resonant cavity matches the main noise frequency under the current rotational speed, thereby achieving adaptive noise reduction; by real-time detection of the fan speed and adjustment of the resonant cavity volume based on the preset mapping table, the resonant frequency adaptively matches the main noise frequency under the current operating condition, achieving real-time tracking and effective suppression of noise at different speeds, overcoming the defects of fixed frequency in traditional passive resonant cavities, and significantly improving the noise reduction effect and user experience under all operating conditions.

[0078] Example 2 Based on the above embodiments, this invention provides another method for reducing noise in range hoods, see [link to relevant documentation]. Figure 7 The flowchart shown in this embodiment of the invention illustrates another method for reducing noise in a range hood. This method includes: Start: Range hood 6 is in standby or in a stable state at a certain setting, waiting for user operation or receiving signals from linked devices.

[0079] Operating condition sensing: The controller monitors the user's gear operation or the fan speed sensor signal in real time to obtain the current speed in RPM. current .

[0080] Feedforward pre-tuning includes: frequency prediction, parameter pre-setting, and fast action; details are as follows: Frequency prediction: based on the current RPM. current By querying the pre-stored mapping table, the current dominant noise frequency f can be directly predicted. predicted .

[0081] Parameter preset: Simultaneously, the corresponding optimal resonant cavity parameters, including the optimal resonant cavity volume V, are retrieved from the mapping table. set and / or optimal control current I set .

[0082] Rapid action: The controller immediately sends a command to the resonant cavity adjustment mechanism (piezoelectric ceramic, SMA, or stepper motor) to drive it to the optimal resonant cavity volume V with the target parameters. set and / or optimal control current I set This process is completed within a very short time (e.g., 100-200ms) after the user switches gears, achieving preemptive vibration suppression.

[0083] Feedback-based fine-tuning includes: effect monitoring, effect evaluation, and adaptive fine-tuning; details are as follows: Effect monitoring: After the feedforward adjustment is completed, a short settling period is delayed, and then a high-precision microphone is started to perform acoustic sampling and FFT spectrum analysis.

[0084] Performance evaluation: Check the current dominant noise frequency f predicted Check whether the sound pressure level is suppressed below a preset threshold (e.g., reduced by more than 15 dB). At the same time, check whether the overall A-weighted sound pressure level meets the standard.

[0085] Adaptive fine-tuning: If the vibration suppression effect meets the standard: maintain the current parameters, and use this successful data to fine-tune the mapping table to make the system more and more accurate.

[0086] If the vibration suppression effect is not satisfactory: initiate the gradient descent fine-tuning algorithm. The controller operates at the optimal resonant cavity volume V under the current parameters. set and / or optimal control current I set A small parameter perturbation ±Δ is applied nearby, and the direction of noise amplitude change is observed. Through several iterations, the actual optimal parameter point and the actual optimal resonant cavity volume V under the current operating conditions are found. optimal and / or the actual optimal control current I optimal This step involves updating the mapping table. It compensates for system drift caused by factors such as oil buildup, temperature changes, and component aging.

[0087] Continuous monitoring and re-triggering: The system continuously runs the above monitoring. Once the current RPM is detected... current If a change occurs, immediately jump back to step "Frequency Prediction" and begin a new round of control loop.

[0088] End: Range hood 6 will continue operating with current parameters.

[0089] The noise reduction method for range hoods provided in this invention has the following beneficial effects: Intelligent noise reduction for an enhanced experience: It delivers on its promise of "quiet at the lowest setting," resolving the pain point of sudden noise increases when switching to higher settings. The noise reduction frequency automatically follows the wind speed, achieving complete silence.

[0090] Eliminating low-frequency noise at its source: The targeted Helmholtz resonant cavity has a far superior effect on suppressing low-frequency rotational noise than traditional sound insulation cotton, and has particularly improved the "buzzing" sound that bothers users.

[0091] High efficiency and energy saving: The topology-optimized air duct significantly reduces airflow resistance. Under the same air volume, the fan load is smaller and the motor power consumption is lower, achieving a balance between energy saving and quiet operation.

[0092] Adaptive and long lifespan: The feedback fine-tuning mechanism enables the system to adapt to environmental changes caused by oil contamination, ensuring that the product maintains excellent noise reduction performance throughout its entire lifespan.

[0093] Compact structure: Topology optimization enables the design of the optimal air duct within the limited internal space of the range hood 6, which is integrated with the resonant cavity without taking up too much extra space.

[0094] Example 3 Based on the above embodiments, this invention provides a range hood 6, including: a tunable Helmholtz resonant cavity and a range hood controller; the tunable Helmholtz resonant cavity has an adjustable-size resonant space, and the resonant space is connected to the air duct of the range hood 6; the air duct is a topology-optimized air duct; the range hood controller is used to execute the range hood noise reduction method provided in the first aspect above.

[0095] Specifically, this range hood system integrates a topology-optimized air duct with a tunable Helmholtz resonant cavity. The air duct, designed using topology optimization to minimize flow resistance and optimize acoustic propagation characteristics, forms a streamlined, low-turbulence structure, suppressing broadband noise at its source. The resonant cavity achieves continuous volume adjustment via a movable valve plate 1 and a displacement mechanism, allowing its resonant frequency to match the main noise frequencies corresponding to changes in fan speed in real time. The controller, based on a preset speed-resonant cavity parameter mapping table and a feedback fine-tuning mechanism, achieves hybrid control of "feedforward pre-adjustment + feedback fine-tuning." This system not only solves the problem of traditional passive resonant cavities being unable to adapt to multiple noise levels, but also achieves a balance between high-efficiency noise reduction and energy-saving operation within a limited space through integrated structural design, significantly improving the user's quiet experience during cooking.

[0096] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working process of the range hood 6 described above can be referred to the corresponding process in the aforementioned embodiments of the range hood noise reduction method, and will not be repeated here.

[0097] Example 4 Based on the above embodiments, this invention provides a smart kitchen system, including: the range hood 6 provided in the above embodiments.

[0098] Specifically, this smart kitchen system centers around a range hood (model 6) with adaptive noise reduction capabilities. It can integrate with kitchen environment sensors, smart cooktops, and air purification equipment to achieve comprehensive intelligent management of the kitchen environment. The range hood (model 6) maintains low-noise operation by adjusting its resonant cavity parameters in real time. Combined with the low-resistance characteristics of its topology-optimized air duct, it reduces energy consumption while ensuring effective smoke extraction. This system embodies the development trend of kitchen appliances towards intelligence, integration, and green technology. It not only improves users' cooking comfort and health but also provides a key noise control node for building a whole-house smart home system, demonstrating significant application value and market potential.

[0099] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working process of the smart kitchen system described above can be referred to the corresponding process in the aforementioned embodiments of the range hood noise reduction method, and will not be repeated here.

[0100] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for reducing noise of a range hood, the method comprising: The application is applied to a range hood controller; the range hood comprises a tunable Helmholtz resonator; the tunable Helmholtz resonator has a resonant space with adjustable size, and the resonant space is in communication with an air duct of the range hood; the method comprises: In response to a change in the working state of the range hood, the rotational speed of the range hood is obtained; Based on a preset rotational speed-resonator parameter mapping table, the target parameter of the tunable Helmholtz resonator is determined; Based on the target parameter, the volume of the resonant space in the tunable Helmholtz resonator is adjusted, so that the resonant frequency of the tunable Helmholtz resonator matches the main noise frequency at the current rotational speed, and adaptive noise reduction is realized.

2. The range hood noise reduction method of claim 1, wherein, The tunable Helmholtz resonator comprises a movable valve plate and a displacement mechanism; one side of the movable valve plate is connected with the displacement mechanism, and the other side forms the resonant space with the side wall of the tunable Helmholtz resonator; the target parameter comprises a target current parameter; based on the target parameter, the volume of the resonant space in the tunable Helmholtz resonator is adjusted, which comprises: Based on the target current parameter, the state of the displacement mechanism is adjusted, so that the movable valve plate moves in the tunable Helmholtz resonator, thereby changing the volume of the resonant space.

3. The range hood noise reduction method of claim 2, wherein, The displacement mechanism comprises a piezoelectric ceramic, a shape memory alloy spring or a stepping motor.

4. The range hood noise reduction method of claim 2, wherein, The tunable Helmholtz resonator further comprises a rigid cavity base; the rigid cavity base is made of a rigid, acoustically inert material; the rigid cavity base has a neck structure; the rigid cavity base is in communication with the air duct of the range hood through the neck structure; the movable valve plate is made of a flexible composite material.

5. The range hood noise reduction method of claim 1, wherein, After the step of adjusting the volume of the resonant space in the tunable Helmholtz resonator based on the target parameter, the method further comprises: Acoustic sampling is performed on the range hood to obtain current noise data; It is judged whether the current noise data meets a preset noise reduction condition; If not, the target parameter is adjusted based on a preset gradient descent fine-tuning algorithm to adjust the noise, and after multiple iterations, the optimal target parameter is determined; Based on the optimal target parameter, the rotational speed-resonator parameter mapping table is updated.

6. The range hood noise reduction method of claim 5, wherein, The rotational speed-resonator parameter mapping table comprises original noise data corresponding to the state of the range hood; the noise reduction condition comprises reducing the sound pressure level of a preset target value; the step of judging whether the current noise data meets the preset noise reduction condition comprises: In the rotational speed-resonator parameter mapping table, the original noise data corresponding to the current state of the range hood is determined; It is judged whether the sound pressure level difference between the original noise data and the current noise data meets the target value.

7. The range hood noise reduction method of claim 1, wherein, Before the step of obtaining the rotational speed of the range hood in response to the change in the working state of the range hood, the method further comprises: In response to the control signal, the working state of the range hood is gradually adjusted from the lowest to the highest; during the adjustment of the gear, the corresponding noise data is collected at each preset speed collection point, and the size of the resonance space is gradually changed at each speed collection point, and the target parameters corresponding to the speed collection point are determined by the noise reduction effect; Based on the speed corresponding to the speed collection point, the noise data and the target parameter mapping generates the speed-resonance cavity parameter mapping table.

8. The range hood noise reduction method of claim 1, wherein, The air duct of the range hood is a topologically optimized air duct; the air duct is determined by the following steps: Through a preset topological optimization algorithm, a basic air duct is generated with the goal of minimizing flow resistance and optimizing acoustic performance; Based on the basic air duct and the tunable Helmholtz resonator corresponding to the multiple target parameters, multiple over-ducts are constructed; Through the topological optimization algorithm, the multiple air ducts are jointly optimized with the goal of minimizing flow loss, and the air duct of the range hood is obtained.

9. A range hood characterized by, Comprise: Tunable Helmholtz resonator and range hood controller; The tunable Helmholtz resonator has an adjustable size resonance space, and the resonance space is in communication with the air duct of the range hood; the air duct is a topologically optimized air duct; the range hood controller is used to execute the range hood noise reduction method of any one of claims 1 to 8.

10. A smart kitchen system, characterized by, Comprise: The range hood of claim 9.

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