Dehumidifier noise reduction control method and control system

Abstract

The invention discloses a dehumidifier noise reduction control method and system, and relates to the technical field of noise reduction control, and the method comprises the steps: installing a noise sensor around a dehumidifier, collecting a noise signal in real time, converting the noise signal into a noise digital signal X, and transmitting the noise digital signal X to a central processing unit for calculation. According to the method, Fourier transform is adopted, a time domain noise signal is converted into a frequency domain signal X (f, t), the time-varying noise power Snoise (f, t) is further calculated, and the frequency and intensity of noise and the change rule of the noise along with time are obtained. Compared with a traditional passive noise reduction mode, the method has the advantages that noise characteristics can be accurately analyzed, and reverse ultrasonic interference waves matched with the noise are emitted by combining an ultrasonic reverse waveform generation mechanism and a phase adjustment mechanism, so that the noise generated during operation of the dehumidifier is effectively counteracted. By means of the scheme, propagation of low-frequency noise can be remarkably reduced in the operation process of the dehumidifier.

Description

Technical Field

[0001] The present invention relates to the technical field of noise reduction control, and specifically provides a dehumidifier noise reduction control method and control system. Background Art

[0002] With the development of the intelligence of household appliances, active noise reduction technology has become an important research direction for improving the home environment. In the field of household appliance noise reduction, especially in devices such as air conditioners, air purifiers, and dehumidifiers, the noise generated during operation has an important impact on the user experience. As a home environment regulation device, a dehumidifier is mainly used to reduce the air humidity, prevent the growth of mold, and improve the air quality. However, the dehumidifier generates obvious low-frequency noise during operation, mainly from its internal compressor, fan, and condensation system. In a quiet environment, such as a bedroom, children's room, or library, the low-frequency noise of the dehumidifier is particularly obvious, which is likely to affect the user's sleep quality and living comfort. Therefore, for the active control of the low-frequency noise of the dehumidifier, researching an efficient ultrasonic noise reduction technology to provide a quiet and comfortable home environment has important research significance and practical application value.

[0003] At present, the dehumidifier noise reduction technology mainly relies on passive noise reduction means, such as using sound insulation cotton, optimizing the air duct design, improving the compressor structure, etc. Although these methods can reduce the noise to a certain extent, due to the long wavelength of low-frequency noise, the effect of passive noise reduction means is very limited, and it is difficult to completely eliminate low-frequency noise. In addition, some attempts use variable frequency control to reduce noise, but this often affects the working efficiency of the dehumidifier and even leads to a decrease in the dehumidification capacity, and it is impossible to maintain normal operation while ensuring noise reduction.

[0004] Another method is the active noise reduction technology, that is, through the principle of sound wave cancellation, using a speaker to emit a reverse sound wave to cancel the noise. However, the traditional ANC technology (i.e., Active Noise Cancellation, a noise reduction technology applied to headphone noise reduction, starting from the noise source itself, trying to reverse the phase of the original noise through electronic circuits) mainly targets air-borne noise. For the low-frequency mechanical noise and air flow noise of the dehumidifier, it is difficult for the traditional ANC system to accurately control the phase matching, resulting in unstable actual noise reduction effect. Therefore, the existing technology has obvious deficiencies in aspects such as low-frequency noise control, noise reduction efficiency, adaptability, and energy consumption. Summary of the Invention

[0005] Aiming at the deficiencies of the existing technology, the present invention provides a dehumidifier noise reduction control method and control system, which solves the problems mentioned in the background art.

[0006] To achieve the above object, the first aspect of the present invention provides a dehumidifier noise reduction control method, including the following steps:

[0007] S1. Obtain the time-varying noise power Snoise of the dehumidifier during operation, and calculate the ultrasonic reverse waveform Pult based on the reverse waveform generation mechanism and the phase adjustment mechanism;

[0008] S2. Based on the ultrasonic reverse waveform Pult, control the ultrasonic transmitter embedded in the dehumidifier to emit reverse ultrasonic interference waves opposite to the noise frequency band;

[0009] S3. After the reverse ultrasonic interference wave is emitted, introduce a dynamic feedback mechanism to calculate the ultrasonic signal adjustment amount △Pult;

[0010] S4. After the dynamic feedback mechanism is executed, extract the original noise and the residual noise for ratio calculation to obtain the residual noise ratio Rnoise, and evaluate the noise reduction effect based on the output result of the residual noise ratio Rnoise; when the residual noise ratio Rnoise ≤ 0, it means that the noise reduction adjustment is normal and no adjustment is required; when the residual noise ratio Rnoise > 0, recalculate the time-varying noise power Snoise(f, t) at the current time t and frequency f, and iteratively execute S1 to S4 to adjust the reverse ultrasonic interference wave until the noise reduction adjustment is normal and the iteration stops.

[0011] In an implementation method, before the S1, it includes:

[0012] By installing noise sensors around the dehumidifier, when the dehumidifier starts to work, the noise signals generated by the dehumidifier itself are collected in real time, and the collection time of each noise signal is recorded by the noise sensors to obtain the noise signals at time t;

[0013] Connect the noise sensors to the central processor of the dehumidifier in signal, and transmit the noise signals collected in real time to the central processor for processing to obtain the frequency-domain signal X(f, t) at time t and frequency f.

[0014] In an implementation method, the transmitting the noise signals collected in real time to the central processor for processing includes:

[0015] After the central processor receives the noise digital signal X in real time, mark the time stamp of the noise digital signal X according to the sampling frequency to obtain the noise digital signal X(t) at time t;

[0016] Convert the noise signal X(t) at time t into the frequency domain of the noise signal at each time t through Fourier transform to generate a noise signal containing frequency information, and obtain the frequency-domain signal X(f, t) at time t and frequency f;

[0017] Integrate the frequency-domain signal X(f,t) at the time t and frequency f to obtain the time-varying noise power Snoise at the time t and frequency f.

[0018] In an implementation method, in the S1, the reverse waveform generation mechanism is to set the amplitude of the ultrasonic signal to be proportional to the square root of the time-varying noise power Snoise(f,t) at the time t and frequency f, and then adjust the gain adjustment factor using a digital signal processor DSP according to the time-variability of the noise power to control the output of the ultrasonic wave and obtain the ultrasonic signal amplitude.

[0019] In an implementation method, in the S1, the phase adjustment mechanism includes basic phase adjustment and dynamic phase adjustment;

[0020] The basic phase adjustment introduces a sine wave component to enable the phase of the ultrasonic signal to adapt to the changes in the non-linear noise signal, keep the phase of the ultrasonic signal always opposite to the noise signal, and obtain the basic phase term of the ultrasonic signal;

[0021] For the dynamic phase adjustment, calculate the time change rate of the time-varying noise power Snoise(f,t), and calculate and output the dynamic phase adjustment term based on the time change rate of the time-varying noise power Snoise(f,t) combined with the dynamic adjustment coefficient to adjust the phase of the ultrasonic signal.

[0022] In an implementation method, in the S1, the calculation expression of the ultrasonic reverse waveform Pult is:

[0023]

[0024] In the formula, Pult(f,t) represents the ultrasonic reverse waveform at the time t and frequency f; represents the ultrasonic signal amplitude; k represents the gain adjustment factor; exp represents the exponential function with the natural constant e as the base; j represents the imaginary unit, and when the phase of the ultrasonic signal is 180° different from that of the noise signal, they will cancel each other out; α represents the linear phase adjustment coefficient; β represents the non-linear phase correction coefficient;, γ represents the non-linear oscillation frequency factor; δ represents the dynamic phase adjustment coefficient; sin represents the sine function; dSnoise(f,t) represents the integration variable of the time-varying noise power Snoise(f,t) at the time t and frequency f, and dt represents the time integration variable.

[0025] In one implementation method, in step S3, the dynamic feedback mechanism calculates the residual time-varying noise power Snoise,res(f,t) at time t and frequency f after active noise cancellation processing, and then calculates the difference between the time-varying noise power Snoise(f,t) at time t and frequency f before active noise cancellation processing and the noise reduction amount of active noise cancellation processing to obtain the target time-varying noise power Snoise(f,t)' at time t and frequency f;

[0026] The residual time-varying noise power Snoise,res(f,t) at time t and frequency f after active noise cancellation processing and the target time-varying noise power Snoise(f,t)' at time t and frequency f are comprehensively calculated to obtain the ultrasonic signal adjustment amount △Pult, and the frequency and phase of the ultrasonic signal are dynamically adjusted based on the ultrasonic signal adjustment amount △Pult.

[0027] In one implementation method, in step S4, the expression of the ultrasonic signal adjustment amount △Pult is:

[0028]

[0029] In the formula, F1 represents the feedback gain coefficient; F2 represents the noise change rate gain coefficient; Snoise,res(f,t) represents the residual time-varying noise power at time t and frequency f; Snoise(f,t)' represents the time-varying noise power.

[0030] In one implementation method, in step S1, the expression of the time-varying noise power Snoise(f,t) is:

[0031]

[0032] In the formula, T represents the length of the time-domain sliding time window; dt represents the time calculus, t - T represents the time period from the past T seconds to the current time t; X(f,t) represents the frequency-domain signal at time t and frequency f.

[0033] In the second aspect of the present application, a noise reduction control system for a dehumidifier is used to apply a noise reduction control method for a dehumidifier as described above, and includes:

[0034] A noise data conversion module, a spectrum analysis module, a reverse ultrasonic waveform generation module, a dynamic feedback adjustment module, and a noise reduction effect evaluation module;

[0035] The noise data conversion module is used to collect noise signals in real time through noise sensors around the dehumidifier and convert them into noise digital signals X, which are transmitted to the central processor of the dehumidifier;

[0036] The spectrum analysis module is used to convert the noise digital signal X in the central processing unit into a frequency-domain signal X(f), and calculate and output the time-varying noise power Snoise based on the frequency-domain signal X(f);

[0037] The reverse ultrasonic waveform generation module is used to execute the reverse waveform generation mechanism and the phase adjustment mechanism according to the time-varying noise power Snoise, and after the execution is completed, summarize the calculation and output the ultrasonic reverse waveform Pult, and control the ultrasonic transmitter embedded in the dehumidifier to emit a reverse ultrasonic interference wave opposite to the noise frequency band;

[0038] The dynamic feedback adjustment module is used to introduce a dynamic feedback mechanism after the reverse ultrasonic interference wave is emitted, calculate and output the ultrasonic signal adjustment amount △Pult, dynamically feedback and adjust the ultrasonic signal, and continuously optimize the noise reduction effect;

[0039] The noise reduction effect evaluation module is used to extract the original noise and the residual noise for ratio calculation after the dynamic feedback mechanism is executed, output the residual noise ratio Rnoise, and evaluate the noise reduction effect based on the output result of the residual noise ratio Rnoise.

[0040] The present invention provides a dehumidifier noise reduction control method and control system. It has the following beneficial effects:

[0041] (1) By installing noise sensors around the dehumidifier, this method can collect noise signals in real time, convert them into noise digital signals X, and transmit them to the central processing unit for calculation. This method uses Fourier transform to convert the time-domain noise signal into a frequency-domain signal X(f,t), and further calculates the time-varying noise power Snoise(f,t) to obtain the frequency, intensity of the noise and its change law over time. Compared with the traditional passive noise reduction method, this method can accurately analyze the noise characteristics, and combine the reverse ultrasonic waveform generation mechanism and the phase adjustment mechanism to emit a reverse ultrasonic interference wave matching the noise, so as to effectively cancel the noise during the operation of the dehumidifier. Through this solution, the dehumidifier can significantly reduce the propagation of low-frequency noise during operation, improve the comfort experience of users in environments such as bedrooms and children's rooms, and avoid noise pollution caused by mechanical resonance or wind noise problems.

[0042] (2) Through a dynamic feedback mechanism, after emitting the reverse ultrasonic signal, the method detects the residual noise after noise reduction in real time, calculates the ultrasonic signal adjustment amount ΔPult, and dynamically adjusts the amplitude and phase of the ultrasonic signal according to the residual noise ratio Rnoise to continuously optimize the noise reduction effect. Specifically, the central processing unit calculates the residual time-varying noise power Snoise,res(f,t) after active noise reduction processing and performs a ratio calculation with the original noise power Snoise(f,t) before noise reduction to measure the current noise reduction effect. When the residual noise ratio Rnoise exceeds the set threshold, the ultrasonic reverse waveform generation mechanism and the phase adjustment mechanism are iteratively executed until the ideal noise reduction level is achieved. Compared with the traditional fixed-parameter noise reduction method, the present invention can perform adaptive optimization according to the changes in the noise environment to ensure that the dehumidifier can still maintain stable and efficient noise reduction ability under different working conditions.

[0043] (3) Based on the analysis results of the time-varying noise power spectrum, the method intelligently adjusts the amplitude and phase of the ultrasonic signal and optimizes the ultrasonic gain adjustment factor through a digital signal processor DSP to ensure that the intensity of the ultrasonic signal does not exceed the set upper and lower limit values, thereby avoiding energy waste. In addition, the phase adjustment mechanism not only includes basic phase adjustment but also optimizes the matching degree of the ultrasonic signal by dynamically adjusting the phase to predict the noise change trend in advance. Combining the calculation of the ultrasonic signal adjustment amount ΔPult, the system can reduce additional energy consumption while ensuring the noise reduction effect, ensuring that the dehumidifier can balance noise reduction and efficient dehumidification. Different from the problem of reduced dehumidification capacity that may be caused by traditional variable-frequency noise reduction technologies, this method does not change the hardware structure of the dehumidifier and only realizes more efficient active noise reduction control through software algorithms and signal processing optimization. This solution not only improves the intelligence level of the dehumidifier but also reduces power consumption, improves the adaptability and noise reduction stability of the system, and has broad application prospects. Description of the Drawings

[0044] Figure 1 Schematic diagram of the steps of a noise reduction control method for a dehumidifier according to the present invention;

[0045] Figure 2 Schematic diagram of the process of a noise reduction control system for a dehumidifier according to the present invention;

[0046] Figure 3 Schematic diagram of the data processing process according to the present invention. Detailed Embodiments

[0047] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0048] Embodiment 1

[0049] Please refer to Figure 1 and Figure 3 , the present invention provides a noise reduction control method for a dehumidifier. To achieve the above objectives, the present invention is realized through the following technical solutions: including the following steps:

[0050] S1. Obtain the time-varying noise power Snoise of the dehumidifier during operation, and calculate the ultrasonic reverse waveform Pult based on the reverse waveform generation mechanism and the phase adjustment mechanism;

[0051] S2. Based on the ultrasonic reverse waveform Pult, control the ultrasonic transmitter embedded in the dehumidifier to emit a reverse ultrasonic interference wave opposite to the noise frequency band;

[0052] S3. After the reverse ultrasonic interference wave is emitted, introduce a dynamic feedback mechanism to calculate the ultrasonic signal adjustment amount △Pult;

[0053] S4. After the dynamic feedback mechanism is executed, extract the original noise and the residual noise for ratio calculation to obtain the residual noise ratio Rnoise, and evaluate the noise reduction effect based on the output result of the residual noise ratio Rnoise; when the residual noise ratio Rnoise ≤ 0, it means that the noise reduction adjustment is normal and no adjustment is required; when the residual noise ratio Rnoise > 0, recalculate the time-varying noise power Snoise(f,t) at the current time t and frequency f, and iteratively execute S1 to S4 to adjust the reverse ultrasonic interference wave until the noise reduction adjustment is normal and the iteration stops.

[0054] Based on the output result of the residual noise ratio Rnoise, analyze and evaluate the noise reduction effect after the current noise reduction optimization. The specific evaluation content is as follows;

[0055] When the residual noise ratio Rnoise ≤ 0, it means that the noise reduction adjustment is normal and no adjustment is required;

[0056] When the residual noise ratio Rnoise > 0, it means that the noise reduction effect is abnormal. At this time, recalculate the time-varying noise power Snoise(f,t) at the current time t and frequency f, and iteratively execute S3 to S5 to adjust the reverse ultrasonic interference wave until the noise reduction adjustment is normal and the iteration stops.

[0057] In this embodiment, the method installs noise sensors around the dehumidifier to collect noise signals in real time and convert them into digital noise signals X, which are then transmitted to the central processor for analysis. Subsequently, the central processor converts the digital noise signal into a frequency-domain signal X(f,t) at time t and frequency f, and calculates the time-varying noise power Snoise(f,t) at time t and frequency f to accurately obtain the frequency, intensity of the noise, and its variation characteristics over time. Based on this noise power data, the reverse waveform generation mechanism and phase adjustment mechanism are executed to generate an ultrasonic reverse waveform Pult(f,t) at time t and frequency f, and the reverse ultrasonic interference wave is emitted through the ultrasonic transmitter, thereby actively interfering with and canceling the noise signal. After the ultrasonic signal is emitted, the method introduces a dynamic feedback mechanism. By measuring the residual time-varying noise power Snoise,res(f,t) at time t and frequency f after noise reduction in real time, calculating the adjustment amount ΔPult(f,t) of the ultrasonic signal at time t and frequency f, and dynamically optimizing the amplitude and phase of the ultrasonic signal according to the calculation results, it is ensured that the noise reduction can adapt to different noise environments and achieve the best noise reduction effect. Finally, through the evaluation of the noise reduction effect, the residual noise ratio Rnoise is calculated, and based on this ratio, it is analyzed whether the current noise reduction effect meets the preset standard. If not, the generation and adjustment of the ultrasonic signal are re-executed to ensure the continuity of noise reduction optimization. Compared with traditional passive noise reduction means, this method can respond to changes in environmental noise in real time and effectively reduce low-frequency noise through the cancellation effect of ultrasonic signals. At the same time, the introduction of the dynamic feedback mechanism can perform adaptive adjustment according to changes in noise power, and achieve more efficient and accurate noise reduction control without affecting the normal operation of the dehumidifier. In addition, by using DSP signal processing technology to dynamically adjust the amplitude and phase of the ultrasonic signal, it is ensured that the noise reduction process is efficient and stable, and no additional energy waste is generated. Finally, while improving the noise reduction performance of the dehumidifier, the present invention significantly improves the user experience, enhances the environmental adaptability of the system, and increases the market competitiveness.

[0058] Embodiment 2

[0059] Please refer to Figure 1 and Figure 3 , specifically, before S1, it further includes:

[0060] S11. By installing noise sensors around the dehumidifier, when the dehumidifier starts to work, the noise signals generated by the dehumidifier itself are collected in real time, the acquisition frequency of the noise sensors is set to twice the noise frequency, the acquisition time of each noise signal is recorded, and the noise signals at time t are obtained.

[0061] The wide-screen noise range of the noise sensor is 20Hz - 40Hz to ensure that various noise components can be identified;

[0062] S12. Wirelessly connect the noise sensor to the central processor of the dehumidifier via Bluetooth, transmit the real-time collected noise signal to the central processor, and convert the noise signal into a noise digital signal X during the transmission process.

[0063] In this embodiment, the method ensures the accuracy of the collected signal by setting the acquisition frequency of the sensor to be twice the noise frequency. At the same time, the wide-screen noise range of the sensor is set to 20Hz - 40Hz, enabling it to cover various noise components generated during the operation of the dehumidifier, ensuring that different frequency band noise information can be accurately captured and analyzed. Subsequently, the noise signal is transmitted to the central processor via wireless Bluetooth connection, and the conversion of the noise signal to the digital signal X is completed during the transmission process for subsequent signal analysis and noise reduction processing. Through this method, the noise information of the dehumidifier can be obtained efficiently and stably, and it is ensured that the noise data is not distorted during the transmission and conversion processes, providing accurate data support for subsequent time-frequency analysis, noise power calculation, and ultrasonic noise reduction processing. Compared with traditional noise reduction methods, the wireless data transmission mode of this solution not only reduces the wiring complexity but also improves the flexibility of noise signal acquisition. In addition, the high-precision noise acquisition mechanism ensures that the noise spectrum information can be accurately obtained, avoiding affecting the noise reduction effect due to insufficient signal acquisition or errors.

[0064] Embodiment 3

[0065] Please refer to Figure 1 and Figure 3 , specifically, the process of transmitting the real-time collected noise signal to the central processor for processing includes:

[0066] S21. Receive the noise digital signal X in real time in the central processor, mark the time stamp for the noise digital signal X according to the acquisition frequency to obtain the noise digital signal X(t) at time t, and convert the noise signal X(t) at time t into the frequency domain representation of the noise signal at each time t through Fourier transform to generate a noise signal containing frequency information, and obtain the frequency domain signal X(f,t) at time t and frequency f.

[0067] S22. Based on the frequency domain signal X(f,t) at time t and frequency f, perform integral processing, and use a sliding time window. The window slides along the change of the noise signal in time, calculate the frequency characteristics of the noise signal within the window, and obtain the time-varying noise power Snoise(f,t) at time t and frequency f.

[0068] The time-varying noise power Snoise(f,t) at time t and frequency f is calculated and output through the following algorithm formula;

[0069]

[0070] In the formula, T represents the length of the time-domain sliding time window, dt represents the time calculus, and t - T represents the time period from the past T seconds to the current time t.

[0071] In this embodiment, the method receives in real time the noise digital signal X collected by the noise sensor within the central processing unit, and marks time stamps for the noise data according to the set acquisition frequency to ensure the time correlation and traceability of the noise signal. Subsequently, using the Fourier transform, the noise digital signal X(t) at time t in the time domain is converted into the frequency-domain signal X(f, t) at time t and frequency f, and the frequency information of the noise is extracted, enabling the accurate analysis of the noise characteristics at different time points and frequency ranges. On this basis, based on the frequency-domain signal X(f, t) at time t and frequency f, an integration operation is performed, and combined with the sliding time window technology, the change trend of the noise signal is analyzed in real time, and the time-varying noise power Snoise(f, t) at time t and frequency f is calculated to accurately evaluate the energy distribution and dynamic characteristics of the noise. The implementation of this method realizes high-precision noise analysis and signal processing, providing a reliable data basis for subsequent ultrasonic reverse waveform generation and dynamic noise reduction optimization. Compared with traditional noise reduction methods, the time-frequency conversion and sliding window analysis technology can capture and predict the change trend of noise in real time, ensuring that the system can still accurately adapt to different noise environments in the face of sudden or continuous noise interference. In addition, based on the calculation of the time-varying noise power Snoise(f, t) at time t and frequency f, targeted noise reduction processing can be carried out at different frequency bands and time points, avoiding the limitations of traditional methods in low-frequency noise control.

[0072] Example 4

[0073] Please refer to Figure 1 and Figure 3 , specifically, in S1, it further includes:

[0074] S31. After obtaining the time-varying noise power Snoise(f, t) at time t and frequency f, execute the reverse waveform generation mechanism and the phase adjustment mechanism;

[0075] The reverse waveform generation mechanism sets the amplitude of the ultrasonic signal to be proportional to the square root of the time-varying noise power Snoise(f, t) at time t and frequency f, and then adjusts the gain adjustment factor using the digital signal processor DSP according to the time-variability of the noise power to control the output of the ultrasonic wave without exceeding the upper limit and the lower limit, and obtains the amplitude of the ultrasonic signal;

[0076] The phase adjustment mechanism includes basic phase adjustment and dynamic phase adjustment;

[0077] The basic phase adjustment introduces a sine wave component, enabling the phase of the ultrasonic signal to adapt to the changes in the non-linear noise signal, keeping the phase of the ultrasonic signal always opposite to that of the noise signal, and obtaining the basic phase term of the ultrasonic signal;

[0078] The dynamic phase adjustment calculates the time variation rate of the time-varying noise power Snoise(f,t), and based on the time variation rate of the time-varying noise power Snoise(f,t) combined with the dynamic adjustment coefficient, calculates and outputs the dynamic phase adjustment term to adjust the phase of the ultrasonic signal in advance.

[0079] S32. Comprehensively calculate the ultrasonic signal amplitude, the basic phase term of the ultrasonic signal, and the dynamic phase adjustment term, output the ultrasonic reverse waveform Pult, and through the digital-to-analog converter DAC, convert the ultrasonic reverse waveform Pult into an analog signal, transmit it to the ultrasonic transmitter, match the frequency and phase of the noise signal, generate a reverse ultrasonic interference wave, and perform preliminary active noise reduction processing on the dehumidifier;

[0080] The ultrasonic reverse waveform Pult is calculated and output through the following algorithm formula;

[0081]

[0082] In the formula, Pult(f,t) represents the ultrasonic reverse waveform at time t and frequency f, k represents the gain adjustment factor, which controls the amplitude of ultrasonic transmission, exp represents the exponential function, j represents the imaginary unit. Physically, when the phase of the ultrasonic signal is opposite to that of the noise signal by 180°, they will cancel each other out to achieve noise reduction. α represents the linear phase adjustment coefficient, β represents the non-linear phase correction coefficient, γ represents the non-linear oscillation frequency factor, δ represents the dynamic phase adjustment coefficient, sin represents the sine function, dSnoise(f,t) represents the integral variable of the time-varying noise power Snoise(f,t) at time t and frequency f, and dt represents the time integral variable;

[0083] Among them represents the ultrasonic signal amplitude;

[0084] represents the phase adjustment term;

[0085] (α·f·t + β·sin(γ·f·t)) represents the basic phase term of the ultrasonic signal. Among them, α·f·t represents that the phase of the ultrasonic signal changes uniformly with time, similar to the basic phase evolution of a noise signal. β·sin(γ·f·t) represents that when the noise signal has strong nonlinear changes, such as the complex noise generated when the device starts up, β can provide additional phase correction to optimize the noise reduction effect. γ is used to control the sine wave oscillation frequency in the phase adjustment, so that the ultrasonic signal can adapt to noises in different frequency ranges;

[0086] represents the dynamic phase adjustment term; among them, δ is used to dynamically adjust the phase according to the noise power change rate to ensure that the system can quickly respond to changes in the noise environment, represents the time change rate of the time-varying noise power Snoise(f, t);

[0087] The above values are all dimensionless processed values.

[0088] In this embodiment, the method obtains the time-varying noise power Snoise(f, t) at time t and frequency f, and executes the reverse waveform generation mechanism and the phase adjustment mechanism to achieve efficient and accurate noise cancellation. First, the reverse waveform generation mechanism adjusts the amplitude of the ultrasonic signal according to the square root of the noise power, and uses a digital signal processor DSP to dynamically adjust the gain factor to ensure that the ultrasonic output is always within the set upper and lower limits, so as to effectively match the noise energy and avoid unnecessary ultrasonic energy consumption. Secondly, the phase adjustment mechanism combines basic phase adjustment and dynamic phase adjustment, so that the ultrasonic signal can adapt to the changing noise environment. Among them, the basic phase adjustment introduces a sine wave component to make the ultrasonic signal have the opposite phase to the nonlinear noise signal to achieve effective noise reduction; the dynamic phase adjustment is based on the time change rate of the time-varying noise power to calculate the dynamic adjustment term, so that the ultrasonic signal can adapt to the fluctuation trend of the noise in advance, improving the response speed and accuracy of the noise reduction system. Subsequently, by comprehensively calculating the ultrasonic signal amplitude, the basic phase term and the dynamic phase adjustment term, the ultrasonic reverse waveform Pult(f, t) at time t and frequency f is generated, and it is converted into an analog signal through a digital-to-analog converter DAC and transmitted to the ultrasonic transmitter to ensure that the transmitted ultrasonic signal matches the noise signal in frequency and phase. Finally, the transmitted reverse ultrasonic interference wave can cancel out the original noise signal during air propagation, realizing active noise reduction. The implementation of this method realizes precise and efficient ultrasonic active noise reduction control. Compared with traditional passive noise reduction means, this method has higher adaptability and real-time response ability. Through the adaptive ultrasonic signal generation mechanism, it can not only process nonlinear noises, but also dynamically adjust the phase according to the change of noise power to ensure that the noise reduction system can maintain the best noise reduction effect in different environments and different working states.

[0089] Example 5

[0090] Please refer to Figure 1 and Figure 3 In the said S3, the dynamic feedback mechanism includes:

[0091] S41. After the preliminary noise reduction treatment of the dehumidifier, the dynamic feedback mechanism is introduced. The dynamic feedback mechanism recalculates the residual time-varying noise power Snoise,res(f,t) of the time t and frequency f after the active noise reduction treatment through S22, which represents the noise power spectrum still existing after noise reduction, that is, the power of the remaining noise signal in the environment after the ultrasonic active noise reduction treatment. Then, the difference between the time-varying noise power Snoise(f,t) at the time t and frequency f before the active noise reduction treatment and the noise reduction amount of the active noise reduction treatment is calculated to obtain the target time-varying noise power Snoise(f,t)' at the time t and frequency f;

[0092] S42. The residual time-varying noise power Snoise,res(f,t) of the time t and frequency f after the active noise reduction treatment and the target time-varying noise power Snoise(f,t)' at the time t and frequency f are comprehensively calculated to output the ultrasonic signal adjustment amount △Pult, dynamically adjust the frequency and phase of the ultrasonic signal, and at the same time dynamically adjust the ultrasonic interference wave in combination with the change rate of the noise to optimize the noise reduction of the dehumidifier;

[0093] The ultrasonic signal adjustment amount △Pult is calculated and output through the following algorithm formula;

[0094]

[0095] In the formula, F1 represents the feedback gain coefficient, which is used to control the magnitude of the ultrasonic signal adjustment amplitude and determines the response speed and intensity of the noise reduction control to the error between the target noise reduction effect and the actual noise reduction effect. F2 represents the noise change rate gain coefficient, which is used to control the response ability of the ultrasonic signal to the change trend of the noise and determines the early response strategy of the noise reduction system to the change trend of the noise power, rising or falling;

[0096] Among them, the residual time-varying noise power Snoise,res(f,t) of the time t and frequency f is the true noise power spectrum after noise reduction and is directly measured;

[0097] The target time-varying noise power Snoise(f,t)' at the time t and frequency f is the target noise power spectrum obtained by optimization calculation, which is the expected noise reduction level to be achieved.

[0098] In this embodiment, the method introduces a dynamic feedback mechanism. After the dehumidifier completes the preliminary noise reduction process, it recalculates the residual time-varying noise power Snoise,res(f,t) at time t and frequency f after the active noise reduction process, that is, the noise energy still remaining after noise reduction. The method re-analyzes the frequency-domain characteristics of the noise through step S22, and calculates the difference between the time-varying noise power Snoise(f,t) at time t and frequency f before noise reduction and the residual time-varying noise power Snoise,res(f,t) at time t and frequency f after noise reduction to obtain the target time-varying noise power Snoise(f,t)' at time t and frequency f, so as to evaluate whether the current noise reduction process reaches the expected effect. On this basis, the residual noise power after the active noise reduction process and the target noise power are comprehensively calculated to generate the ultrasonic signal adjustment amount ΔPult(f,t) at time t and frequency f, and the matching effect of the ultrasonic interference wave is optimized by dynamically adjusting the frequency and phase of the ultrasonic signal. At the same time, the system combines the noise change rate to predict the noise trend in advance, realizes the intelligent adaptive adjustment of the ultrasonic signal, and further improves the response ability of the noise reduction system. The implementation of this method realizes a noise reduction optimization mechanism based on real-time feedback. Compared with the traditional fixed-parameter noise reduction scheme, this method can accurately identify and adapt to the changes in the noise environment, ensuring that the noise reduction adjustment is always in the optimal working state. By calculating the ultrasonic signal adjustment amount ΔPult(f,t) at time t and frequency f, this method can dynamically optimize the intensity and phase of the ultrasonic signal according to the size of the noise reduction error, so that the noise reduction system can stably and effectively reduce noise under different working conditions.

[0099] In this embodiment, the method uses a dynamic feedback mechanism to recalculate and evaluate the noise reduction effect after the active noise reduction system runs, ensuring that the noise reduction system can adapt to different noise environments and achieve continuous optimization. Specifically, after executing the dynamic feedback mechanism, the residual time-varying noise power Snoise,res(f,t)' after noise reduction is recalculated based on step S22, and the ratio is calculated with the time-varying noise power Snoise(f,t) at time t and frequency f before noise reduction to obtain the residual noise ratio Rnoise, which is used to measure the effectiveness of the current noise reduction process. Subsequently, based on the calculated Rnoise value, the noise reduction effect is evaluated to determine whether the current noise reduction reaches the expected optimization goal. The implementation of this method realizes an active noise reduction optimization strategy based on data driving. Compared with the traditional fixed noise reduction parameter control, this method can accurately quantify the noise reduction effect and perform adaptive optimization according to the noise reduction error, ensuring that it is always in the best noise reduction state. Through the calculation and dynamic evaluation mechanism of the residual noise ratio Rnoise, this method not only improves the noise reduction accuracy but also can continuously adapt to the noise changes under different working environments. Whether it is the change of the equipment operation mode or external noise interference, accurate and stable noise reduction control can be achieved.

[0100] Example 6

[0101] Please refer to Figure 1 and Figure 2 , a noise reduction control system for a dehumidifier, comprising a noise data conversion module, a spectrum analysis module, a reverse ultrasonic waveform generation module, a dynamic feedback adjustment module and a noise reduction effect evaluation module;

[0102] The noise data conversion module installs noise sensors around the dehumidifier, collects noise signals in real time, and converts them into noise digital signals X, which are transmitted to the central processor of the dehumidifier;

[0103] The spectrum analysis module converts the noise digital signal X into a frequency domain signal X(f) in the central processor, and calculates and outputs the time-varying noise power Snoise based on the frequency domain signal X(f);

[0104] The reverse ultrasonic waveform generation module executes a reverse waveform generation mechanism and a phase adjustment mechanism based on the time-varying noise power Snoise, and after completion, aggregates and calculates and outputs an ultrasonic reverse waveform Pult, controlling an ultrasonic transmitter embedded in the dehumidifier to emit a reverse ultrasonic interference wave opposite to the noise frequency band;

[0105] The dynamic feedback adjustment module introduces a dynamic feedback mechanism after the emission of the reverse ultrasonic interference wave, calculates and outputs an ultrasonic signal adjustment amount △Pult, dynamically feedback adjusts the ultrasonic signal, and continuously optimizes the noise reduction effect;

[0106] The noise reduction effect evaluation module extracts the original noise and the residual noise for ratio calculation after the execution of the dynamic feedback mechanism, outputs a residual noise ratio Rnoise, and evaluates the noise reduction effect based on the output result of the residual noise ratio Rnoise.

[0107] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention.

Claims

1. A dehumidifier noise reduction control method, characterized in that: The following steps are involved: S1. Obtain the time-varying noise power Snoise of the dehumidifier during operation, and calculate the ultrasonic reverse waveform Pult based on the reverse waveform generation mechanism and the phase adjustment mechanism; S2, based on the ultrasonic reverse waveform Pult, controlling the ultrasonic transmitter embedded in the dehumidifier to emit a reverse ultrasonic interference wave opposite to the noise frequency band; S3, after the reverse ultrasonic interference wave is emitted, a dynamic feedback mechanism is introduced to calculate the ultrasonic signal adjustment amount △Pult; S4. After the dynamic feedback mechanism is executed, extract the original noise and the residual noise to perform ratio calculation to obtain a residual noise ratio Rnoise, and evaluate the noise reduction effect based on an output result of the residual noise ratio Rnoise; When the residual noise ratio Rnoise≤0, it means that the noise reduction adjustment is normal and no adjustment is required; when the residual noise ratio Rnoise>0, the time-varying noise power Snoise(f,t) at the current time t and frequency f is recalculated, and S1 to S4 are iteratively executed to adjust the reverse ultrasonic interference wave until the noise reduction adjustment is normal and the iteration is stopped.

2. A dehumidifier noise reduction control method according to claim 1, characterized in that: Before said S1, including: By installing noise sensors around the dehumidifier, when the dehumidifier starts working, the noise signal generated by the dehumidifier itself is collected in real time, and the collection time of each noise signal is recorded by the noise sensor to obtain the noise signal at time t; The noise sensor is connected to the central processor of the dehumidifier by signal connection, and the noise signal collected in real time is transmitted to the central processor for processing to obtain a frequency domain signal X(f, t) at time t and frequency f.

3. A dehumidifier noise reduction control method according to claim 2, characterized in that: The transmitting the noise signal collected in real time to the central processor for processing includes: After receiving the noise digital signal X in real time in the central processor, the noise digital signal X is timestamped according to the acquisition frequency to obtain the noise digital signal X(t) at time t; The noise signal (t) at time t is converted into the frequency domain of the noise signal at each time t by Fourier transform, generating a noise signal containing frequency information, and obtaining a frequency domain signal X(f,t) at time t and frequency f; The frequency domain signal X(f, t) at the time t and frequency f is integrated to obtain the time-varying noise power Snoise at the time t and frequency f.

4. A dehumidifier noise reduction control method according to claim 1, characterized in that: In S1, the reverse waveform generation mechanism is to set the amplitude of the ultrasonic signal to be proportional to the square root of the time-varying noise power Snoise(f, t) at time t and frequency f, and then use the digital signal processor DSP to adjust the gain adjustment factor according to the time-varying nature of the noise power to control the output of the ultrasonic wave and obtain the ultrasonic signal amplitude.

5. A dehumidifier noise reduction control method according to claim 1, characterized in that: In said S1, said phase adjustment mechanism includes basic phase adjustment and dynamic phase adjustment; The basic phase adjustment introduces a sine wave component so that the phase of the ultrasonic signal can adapt to the change of the nonlinear noise signal, keep the phase of the ultrasonic signal always opposite to the noise signal, and obtain the basic phase term of the ultrasonic signal; The dynamic phase adjustment is performed by calculating the time change rate of the time-varying noise power Snoise(f, t), and based on the time change rate of the time-varying noise power Snoise(f, t) combined with the dynamic adjustment coefficient, a dynamic phase adjustment item is calculated and output to adjust the phase of the ultrasonic signal.

6. A dehumidifier noise reduction control method according to claim 1, characterized in that: In S1, the calculation expression of the ultrasonic reverse waveform Pult is: Where Pult(f,t) represents the ultrasonic reverse waveform at time t and frequency f; represents the amplitude of the ultrasonic signal; k represents the gain adjustment factor; exp represents the exponential function with the natural constant e as the base; j represents the imaginary unit. When the phase of the ultrasonic signal is 180° opposite to that of the noise signal, they will cancel each other out; α represents the linear phase adjustment coefficient; β represents the nonlinear phase correction coefficient; γ represents the nonlinear oscillation frequency factor; δ represents the dynamic phase adjustment coefficient; sin represents the sine function; dSnoise(f,t) represents the integral variable of the time-varying noise power Snoise(f,t) at time t and frequency f, and dt represents the time integral variable.

7. A dehumidifier noise reduction control method according to claim 6, characterized in that: In S3, the dynamic feedback mechanism calculates the residual time-varying noise power Snoise,res(f,t) at time t and frequency f after active noise reduction processing, and then calculates the difference between the time-varying noise power Snoise(f,t) at time t and frequency f before active noise reduction processing and the noise reduction amount of active noise reduction processing to obtain the target time-varying noise power Snoise(f,t)' at time t and frequency f; The residual time-varying noise power Snoise,res(f,t) at time t and frequency f after active noise reduction processing and the target time-varying noise power Snoise(f,t)' at time t and frequency f are comprehensively calculated to obtain the ultrasonic signal adjustment amount △Pult, and the frequency and phase of the ultrasonic signal are dynamically adjusted based on the ultrasonic signal adjustment amount △Pult.

8. A dehumidifier noise reduction control method according to claim 7, characterized in that: In S4, the ultrasonic signal adjustment amount ΔPult is expressed as: Where, F1 represents the feedback gain coefficient; F2 represents the noise change rate gain coefficient; Snoise,res(f,t) represents the residual time-varying noise power of time t and frequency f; Snoise(f,t)' represents the time-varying noise power.

9. A dehumidifier noise reduction control method according to claim 7, characterized in that: In S1, the expression of the time-varying noise power Snoise(f, t) is: In the formula, T represents the length of the time domain sliding time window; dt represents the time calculus, tT represents the time period from the past T seconds to the current time t; X(f,t) represents the frequency domain signal at time t and frequency f.

10. A dehumidifier noise reduction control system, used for applying a dehumidifier noise reduction control method according to any one of claims 1 to 9, characterized in that: include: Noise data conversion module, spectrum analysis module, reverse ultrasonic waveform generation module, dynamic feedback adjustment module and noise reduction effect evaluation module; The noise data conversion module is used to collect noise signals in real time through noise sensors around the dehumidifier, convert them into noise digital signals X, and transmit them to the central processor of the dehumidifier; The spectrum analysis module is used to convert the noise digital signal X in the central processor into a frequency domain signal X(f), and calculate and output the time-varying noise power Snoise based on the frequency domain signal X(f); The reverse ultrasonic waveform generation module is used to execute the reverse waveform generation mechanism and the phase adjustment mechanism according to the time-varying noise power Snoise, and after the execution is completed, summarize and calculate the output ultrasonic reverse waveform Pult, and control the ultrasonic transmitter embedded in the dehumidifier to emit a reverse ultrasonic interference wave opposite to the noise frequency band; The dynamic feedback adjustment module is used to introduce a dynamic feedback mechanism after the reverse ultrasonic interference wave is emitted, calculate the output ultrasonic signal adjustment amount ΔPult, dynamically feedback and adjust the ultrasonic signal, and continuously optimize the noise reduction effect; The noise reduction effect evaluation module is used to extract the original noise and the residual noise for ratio calculation after the dynamic feedback mechanism is executed, output the residual noise ratio Rnoise, and evaluate the noise reduction effect based on the output result of the residual noise ratio Rnoise.

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