A method and control system for noise reduction in dehumidifiers

Abstract

This invention discloses a noise reduction control method and control system for dehumidifiers, belonging to the field of noise reduction control technology. The method involves installing noise sensors around the dehumidifier to collect noise signals in real time, converting them into a digital noise signal X, and transmitting it to a central processing unit for calculation. The method employs 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 noise frequency, intensity, and its variation over time. Compared to traditional passive noise reduction methods, this method can accurately analyze noise characteristics and, combined with an ultrasonic reverse waveform generation mechanism and phase adjustment mechanism, emits a reverse ultrasonic interference wave that matches the noise, thereby effectively eliminating noise during dehumidifier operation. Through this scheme, the propagation of low-frequency noise can be significantly reduced during dehumidifier operation.

Description

Technical Field

[0001] This invention relates to the field of noise reduction control technology, specifically to a noise reduction control method and control system for a dehumidifier. Background Technology

[0002] With the development of smart home appliances, active noise reduction technology has become an important research direction for improving the home environment. In the field of home appliance noise reduction, especially in devices such as air conditioners, air purifiers, and dehumidifiers, the noise generated during operation has a significant impact on user experience. Dehumidifiers, as home environment conditioning devices, are mainly used to reduce air humidity, prevent mold growth, and improve air quality. However, dehumidifiers generate significant low-frequency noise during operation, primarily originating from their internal compressor, fan, and condensation system. In quiet environments, such as bedrooms, children's rooms, or libraries, the low-frequency noise from dehumidifiers is particularly noticeable, easily affecting users' sleep quality and comfort. Therefore, researching an efficient ultrasonic noise reduction technology for the active control of low-frequency noise in dehumidifiers to provide a quiet and comfortable home environment has significant research significance and practical application value.

[0003] Currently, dehumidifier noise reduction technology mainly relies on passive noise reduction methods, such as using sound-absorbing cotton, optimizing air duct design, and improving compressor structure. While these methods can reduce noise to some extent, the effect of passive noise reduction is very limited due to the longer wavelength of low-frequency noise, making it difficult to completely eliminate low-frequency noise. Furthermore, some attempts have tried to reduce noise using variable frequency control, but this often affects the dehumidifier's operating efficiency and may even lead to a decrease in dehumidification capacity, making it impossible to maintain normal operation while ensuring noise reduction.

[0004] Another approach is active noise cancellation (ANC), which uses the principle of sound wave cancellation to cancel out noise by having a speaker emit an inverse sound wave. However, traditional ANC technology (Active Noise Cancellation, a noise reduction technology used in headphones that addresses the noise source by reversing its phase using electronic circuitry) primarily targets airborne noise. For the low-frequency mechanical and airflow noise of dehumidifiers, traditional ANC systems struggle to accurately control phase matching, leading to inconsistent noise reduction performance. Therefore, existing technologies have significant shortcomings in low-frequency noise control, noise reduction efficiency, adaptability, and energy consumption. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this 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 objectives, the first aspect of the present invention provides a dehumidifier noise reduction control method, comprising 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 phase adjustment mechanism.

[0008] S2. Based on the ultrasonic reverse waveform Pult, control the ultrasonic transmitter embedded inside the dehumidifier to emit a reverse ultrasonic interference wave that is opposite to the noise frequency band.

[0009] S3. After the reverse ultrasonic interference wave is emitted, a dynamic feedback mechanism is introduced to calculate the ultrasonic signal adjustment amount ΔPult.

[0010] S4. After the dynamic feedback mechanism is completed, the ratio of the original noise to the residual noise is extracted and calculated to obtain the residual noise ratio Rnoise. The noise reduction effect is evaluated based on the output 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 needed. 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 the reverse ultrasonic interference wave is adjusted by iteratively executing S1 to S4 until the noise reduction adjustment is normal and the iteration stops.

[0011] In one implementation, prior to S1, the method includes:

[0012] By installing noise sensors around the dehumidifier, the noise signals generated by the dehumidifier itself are collected in real time when the dehumidifier starts working. The noise sensors record the time of each noise signal collection to obtain the noise signal at time t.

[0013] The noise sensor is connected to the central processing unit of the dehumidifier, and the noise signal collected in real time is transmitted to the central processing unit for processing to obtain the frequency domain signal X(f,t) at time t and frequency f.

[0014] In one implementation method, transmitting the real-time acquired noise signal to the central processing unit for processing includes:

[0015] After receiving the noise digital signal X in real time, the central processing unit marks the noise digital signal X with a timestamp according to the acquisition frequency to obtain the noise digital signal X(t) at time t.

[0016] 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 the frequency domain signal X(f,t) at time t and frequency f.

[0017] The time-varying noise power Snoise is obtained by integrating the frequency domain signal X(f,t) at time t and frequency f.

[0018] In one implementation, 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, based on the time-varying nature of the noise power, use a digital signal processor (DSP) to adjust the gain adjustment factor to control the output of the ultrasonic wave, thereby obtaining the amplitude of the ultrasonic signal.

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

[0020] The basic phase adjustment introduces a sinusoidal component, enabling the phase of the ultrasonic signal to adapt to changes in the nonlinear noise signal, maintaining the phase of the ultrasonic signal always opposite to that of the noise signal, and obtaining the basic phase term of the ultrasonic signal.

[0021] The dynamic phase adjustment is achieved by calculating the time-varying noise power Snoise(f,t) and then combining the time-varying noise power Snoise(f,t) with a dynamic adjustment coefficient to calculate and output a dynamic phase adjustment term, thereby adjusting the phase of the ultrasonic signal.

[0022] In one implementation, in step S1, the calculation expression for the ultrasonic reverse waveform Pult is:

[0023]

[0024] In the formula, Pult(f,t) represents the reverse waveform of the ultrasonic wave at time t and frequency f; denoted by , where 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, which cancels out the ultrasonic signal when its phase is 180° opposite to the noise signal; 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.

[0025] In one implementation method, 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.

[0026] 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 ΔPult, and the frequency and phase of the ultrasonic signal are dynamically adjusted based on the ultrasonic signal adjustment amount ΔPult.

[0027] In one implementation, in step S4, the expression for the ultrasonic signal adjustment amount ΔPult is:

[0028]

[0029] In the formula, F1 represents the feedback gain coefficient; F2 represents the noise rate of change 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, in step S1, the time-varying noise power Snoise(f,t) is expressed as:

[0031]

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

[0033] The second aspect of this application discloses a dehumidifier noise reduction control system for applying the dehumidifier noise reduction control method described above, comprising:

[0034] The module includes 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, convert them into noise digital signals X, and transmit them to the central processing unit 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 phase adjustment mechanism according to the time-varying noise power Snoise. After execution, it summarizes and calculates to output the ultrasonic reverse waveform Pult, and controls 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 the adjustment amount ΔPult of the output ultrasonic signal, and dynamically adjust the ultrasonic signal to continuously optimize the noise reduction effect.

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

[0040] This invention provides a method and control system for noise reduction in dehumidifiers. It has the following beneficial effects:

[0041] (1) This method involves installing noise sensors around the dehumidifier to collect noise signals in real time, converting them into digital noise signals X, and transmitting them to the central processing unit for calculation. The 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, and time-varying variation of the noise. Compared to traditional passive noise reduction methods, this method can accurately analyze noise characteristics and, combined with an ultrasonic reverse waveform generation mechanism and phase adjustment mechanism, emits a reverse ultrasonic interference wave that matches the noise, thereby effectively eliminating noise during dehumidifier operation. Through this scheme, the dehumidifier can significantly reduce the propagation of low-frequency noise during operation, improving the user's comfort experience in environments such as bedrooms and children's rooms, while avoiding noise pollution caused by mechanical resonance or wind noise.

[0042] (2) This method uses a dynamic feedback mechanism to detect the residual noise after noise reduction in real time after transmitting a reverse ultrasonic signal, calculate the ultrasonic signal adjustment amount ΔPult, and dynamically adjust 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 compares it with the original noise power Snoise(f,t) before noise reduction to measure the effect of the current noise reduction processing. When the residual noise ratio Rnoise exceeds a set threshold, the ultrasonic reverse waveform generation mechanism and phase adjustment mechanism are iteratively executed until the ideal noise reduction level is reached. Compared with traditional fixed parameter noise reduction methods, this invention can adaptively optimize according to changes in the noise environment, ensuring that the dehumidifier can maintain stable and efficient noise reduction capabilities under different working conditions.

[0043] (3) This method intelligently adjusts the amplitude and phase of the ultrasonic signal based on the analysis results of the time-varying noise power spectrum, 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 limits, thereby avoiding energy waste. In addition, the phase adjustment mechanism not only includes basic phase adjustment, but also predicts the noise change trend in advance through dynamic phase adjustment to optimize the matching degree of the ultrasonic signal. Combined with 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. Unlike the problem of reduced dehumidification capacity that may be caused by traditional frequency conversion noise reduction technology, this method does not change the hardware structure of the dehumidifier, but only optimizes the software algorithm and signal processing to achieve more efficient active noise reduction control. This scheme 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. Attached Figure Description

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

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

[0046] Figure 3 This is a schematic diagram of the data processing flow of the present invention. Detailed Implementation

[0047] 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. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0048] Example 1

[0049] Please see Figure 1 and Figure 3 This invention provides a method for noise reduction control in dehumidifiers. To achieve the above objectives, this invention employs the following technical solution, comprising 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 phase adjustment mechanism.

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

[0052] S3. After the reverse ultrasonic interference wave is emitted, a dynamic feedback mechanism is introduced to calculate the ultrasonic signal adjustment amount ΔPult.

[0053] S4. After the dynamic feedback mechanism is completed, the ratio of the original noise to the residual noise is extracted and calculated to obtain the residual noise ratio Rnoise. The noise reduction effect is evaluated based on the output 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 needed. 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 the reverse ultrasonic interference wave is adjusted by iteratively executing S1 to S4 until the noise reduction adjustment is normal and the iteration stops.

[0054] Based on the output of the residual noise ratio Rnoise, the noise reduction effect after the current noise reduction optimization is evaluated. The specific evaluation content is as follows:

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

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

[0057] In this embodiment, the method involves installing 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 a central processing unit (CPU) for analysis. The CPU then converts the digital noise signals into frequency domain signals 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 noise's frequency, intensity, and its time-varying characteristics. Based on this noise power data, a reverse waveform generation mechanism and a phase adjustment mechanism are executed to generate an ultrasonic reverse waveform Pult(f,t) at time t and frequency f. A reverse ultrasonic interference wave is then emitted through an ultrasonic transmitter to actively interfere with and cancel the noise signal. After the ultrasonic signal is emitted, this 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, the adjustment amount ΔPult(f,t) of the ultrasonic signal at time t and frequency f is calculated. Based on the calculation results, the amplitude and phase of the ultrasonic signal are dynamically optimized to ensure that the noise reduction can adapt to different noise environments and achieve the best noise reduction effect. Finally, the residual noise ratio Rnoise is calculated through noise reduction effect evaluation. Based on this ratio, it is analyzed whether the current noise reduction effect meets the preset standard. If not, the ultrasonic signal generation and adjustment are re-executed to ensure the continuity of noise reduction optimization. Compared with traditional passive noise reduction methods, 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. Simultaneously, the introduction of a dynamic feedback mechanism allows for adaptive adjustment based on changes in noise power, achieving more efficient and precise noise reduction control without affecting the normal operation of the dehumidifier. Furthermore, the amplitude and phase of the ultrasonic signal are dynamically adjusted using DSP signal processing technology to ensure efficient and stable noise reduction without generating additional energy waste. Ultimately, this invention significantly improves the user experience, enhances the system's environmental adaptability, and increases its market competitiveness while improving the noise reduction performance of the dehumidifier.

[0058] Example 2

[0059] Please see Figure 1 and Figure 3 Specifically, prior to S1, the following is also included:

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

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

[0062] S12. The noise sensor is wirelessly connected to the central processing unit of the dehumidifier via Bluetooth. The noise signal collected in real time is transmitted to the central processing unit, and during the transmission process, the noise signal is converted into a noise digital signal X.

[0063] In this embodiment, the method ensures the accuracy of the acquired signal by setting the sensor's acquisition frequency to twice the noise frequency. Simultaneously, the sensor's wide-screen noise range is set to 20Hz-40Hz, covering various noise components generated during dehumidifier operation, ensuring accurate capture and analysis of noise information across different frequency bands. Subsequently, the noise signal is transmitted to the central processing unit via wireless Bluetooth, and during transmission, the noise signal is converted into a digital signal X for subsequent signal analysis and noise reduction processing. This method efficiently and stably acquires dehumidifier noise information, ensuring that the noise data is not distorted during transmission and conversion, providing accurate data support for subsequent time-frequency analysis, noise power calculation, and ultrasonic noise reduction processing. Compared to traditional noise reduction methods, this solution's wireless data transmission mode not only reduces wiring complexity but also improves the flexibility of noise signal acquisition. Furthermore, the high-precision noise acquisition mechanism ensures accurate acquisition of noise spectrum information, avoiding the impact of insufficient signal acquisition or errors on the noise reduction effect.

[0064] Example 3

[0065] Please see Figure 1 and Figure 3 Specifically, the step of transmitting the real-time acquired noise signal to the central processing unit for processing includes:

[0066] S21. The central processing unit receives the noise digital signal X in real time, and according to the acquisition frequency, timestamps the noise digital signal X to obtain the noise digital signal X(t) at time t. Then, it converts the noise signal (t) at time t into a frequency domain representation of the noise signal at each time t through Fourier transform, generates a noise signal containing frequency information, and obtains the frequency domain signal X(f,t) at time t and frequency f.

[0067] S22. Based on the frequency domain signal X(f,t) under the time t and frequency f, perform integration processing, and use a sliding time window to analyze the window sliding 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) under the time t and frequency f.

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

[0069]

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

[0071] In this embodiment, the method receives the noise digital signal X collected by the noise sensor in real time within the central processing unit, and timestamps the noise data according to the set acquisition frequency to ensure the temporal correlation and traceability of the noise signal. Subsequently, using Fourier transform, the noise digital signal X(t) at time t is converted into a frequency domain signal X(f,t) at time t and frequency f, extracting the frequency information of the noise and enabling precise analysis of noise characteristics at different time points and frequency ranges. Based on this, an integral operation is performed on the frequency domain signal X(f,t) at time t and frequency f, and combined with a sliding time window technique, the changing trend of the noise signal is analyzed in real time to calculate the time-varying noise power Snoise(f,t) at time t and frequency f, accurately assessing the energy distribution and dynamic characteristics of the noise. The implementation of this method achieves high-precision noise analysis and signal processing, providing a reliable data foundation for subsequent ultrasonic reverse waveform generation and dynamic noise reduction optimization. Compared to traditional noise reduction methods, time-frequency conversion and sliding window analysis techniques can capture and predict noise trends in real time, ensuring that the system can accurately adapt to different noise environments even when faced with sudden or continuous noise interference. Furthermore, based on the calculation of time-varying noise power Snoise(f,t) at time t and frequency f, targeted noise reduction processing can be performed at different frequency bands and time points, avoiding the limitations of traditional methods in low-frequency noise control.

[0072] Example 4

[0073] Please see Figure 1 and Figure 3 Specifically, S1 also 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 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. Based on the time-varying nature of the noise power, a digital signal processor (DSP) is used to adjust the gain adjustment factor to control the output of the ultrasonic signal, ensuring that it does not exceed the upper and lower limits, thereby obtaining 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 sinusoidal component, enabling the phase of the ultrasonic signal to adapt to changes in the nonlinear noise signal, maintaining 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 is achieved by calculating the time-varying noise power Snoise(f,t) and then combining the time-varying noise power Snoise(f,t) with a dynamic adjustment coefficient to calculate and output a dynamic phase adjustment term, thereby adjusting the phase of the ultrasonic signal in advance.

[0079] S32. The ultrasonic signal amplitude, the basic phase term and the dynamic phase adjustment term are calculated together to output the ultrasonic reverse waveform Pult. The ultrasonic reverse waveform Pult is converted into an analog signal by a digital-to-analog converter (DAC) and transmitted to the ultrasonic transmitter to match the frequency and phase of the noise signal, generate a reverse ultrasonic interference wave, and perform preliminary active noise reduction on the dehumidifier.

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

[0081]

[0082] In the formula, Pult(f,t) represents the reverse waveform of the ultrasonic wave at time t and frequency f, k represents the gain adjustment factor, which controls the amplitude of the ultrasonic wave emission, exp represents the exponential function, j represents the imaginary unit, which means that when the phase of the ultrasonic signal is 180° opposite to the noise signal, they will cancel each other out, thus achieving noise reduction, 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;

[0083] in Indicates the amplitude of the ultrasonic signal;

[0084] Indicates the phase adjustment term;

[0085] (α·f·t+β·sin(γ·f·t)) represents the fundamental phase term of the ultrasonic signal, where α·f·t indicates that the phase of the ultrasonic signal changes uniformly with time, similar to the fundamental phase evolution of noise signals. β·sin(γ·f·t) indicates that when the noise signal has strong nonlinear changes, such as the complex noise generated when the equipment starts up, β can provide additional phase correction to optimize the noise reduction effect. γ is used to control the sinusoidal oscillation frequency in phase adjustment, so that the ultrasonic signal can adapt to noise in different frequency ranges.

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

[0087] All the above values ​​are dimensionless values.

[0088] In this embodiment, the method obtains the time-varying noise power Snoise(f,t) at time t and frequency f, and executes an inverse waveform generation mechanism and a phase adjustment mechanism to achieve efficient and accurate noise cancellation. First, the inverse waveform generation mechanism adjusts the amplitude of the ultrasonic signal based on the square root of the noise power and uses a digital signal processor (DSP) to dynamically adjust the gain factor, ensuring that the ultrasonic output is always within the set upper and lower limits, thereby effectively matching the noise energy and avoiding unnecessary ultrasonic energy consumption. Second, the phase adjustment mechanism combines basic phase adjustment and dynamic phase adjustment, enabling the ultrasonic signal to adapt to changing noise environments. Basic phase adjustment introduces a sinusoidal component to keep the ultrasonic signal and nonlinear noise signal in opposite phase, achieving effective noise reduction. Dynamic phase adjustment calculates a dynamic adjustment term based on the time-varying noise power change rate, allowing the ultrasonic signal to adapt to noise fluctuations in advance, improving the response speed and accuracy of the noise reduction system. Subsequently, by comprehensively calculating the ultrasonic signal amplitude, fundamental phase term, and dynamic phase adjustment term, an ultrasonic inverse waveform Pult(f,t) at time t and frequency f is generated. This waveform is then converted into an analog signal by a digital-to-analog converter (DAC) and transmitted to the ultrasonic transmitter, ensuring that the transmitted ultrasonic signal matches the noise signal in frequency and phase. Ultimately, the transmitted inverse ultrasonic interference wave cancels out the original noise signal during air propagation, achieving active noise reduction. This method achieves precise and efficient active ultrasonic noise reduction control. Compared to traditional passive noise reduction methods, this method possesses higher adaptability and real-time response capabilities. Through an adaptive ultrasonic signal generation mechanism, it can not only handle nonlinear noise but also dynamically adjust the phase according to changes in noise power, ensuring that the noise reduction system maintains optimal noise reduction performance under different environments and operating conditions.

[0089] Example 5

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

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

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

[0093] The ultrasonic signal adjustment amount △Pult is calculated and output using 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. It 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 capability of the ultrasonic signal to the noise change trend. It determines the noise reduction system's early response strategy to the noise power change trend, whether it is rising or falling.

[0096] Wherein, the residual time-varying noise power Snoise and res(f,t) are the noise power spectrum after noise reduction, which is obtained by direct measurement.

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

[0098] In this embodiment, the method introduces a dynamic feedback mechanism. After the dehumidifier completes the initial noise reduction process, it recalculates the residual time-varying noise power Snoise,res(f,t) at time t and frequency f after active noise reduction, representing the noise energy that still exists after noise reduction. The method re-analyzes the noise frequency domain characteristics in step S22 and calculates the difference between the time-varying noise power Snoise(f,t) before noise reduction and the residual time-varying noise power Snoise,res(f,t) after noise reduction at time t and frequency f to obtain the target time-varying noise power Snoise(f,t)' at time t and frequency f, thereby evaluating whether the current noise reduction process has achieved the expected effect. Based on this, the residual noise power after active noise reduction and the target noise power are comprehensively calculated to generate the ultrasonic signal adjustment amount ΔPult(f,t) at time t and frequency f. The matching effect of the ultrasonic interference wave is optimized by dynamically adjusting the frequency and phase of the ultrasonic signal. Simultaneously, the system combines the noise change rate to predict noise trends in advance, achieving intelligent adaptive adjustment of the ultrasonic signal and further improving the response capability of the noise reduction system. The implementation of this method achieves a noise reduction optimization mechanism based on real-time feedback. Compared with traditional fixed-parameter noise reduction schemes, this method can accurately identify and adapt to changes in the noise environment, ensuring that the noise reduction adjustment is always in the optimal working state. By calculating the ultrasonic signal adjustment 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 magnitude of the noise reduction error, enabling the noise reduction system to stably and effectively reduce noise under different operating 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 has been running, 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 of this ratio to the time-varying noise power Snoise(f,t) at time t and frequency f before noise reduction is calculated 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 has achieved the expected optimization goal. The implementation of this method realizes a data-driven active noise reduction optimization strategy. Compared with traditional fixed noise reduction parameter control, this method can accurately quantify the noise reduction effect and perform adaptive optimization based on the noise reduction error, ensuring that it is always in the best noise reduction state. By calculating and dynamically evaluating the residual noise ratio Rnoise, this method not only improves noise reduction accuracy but also continuously adapts to noise changes in different working environments. Whether it is a change in equipment operating mode or external noise interference, it can achieve precise and stable noise reduction control.

[0100] Example 6

[0101] Please see Figure 1 and Figure 2 A dehumidifier noise reduction control system includes 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 collects noise signals in real time by installing noise sensors around the dehumidifier, converts them into digital noise signals X, and transmits them to the central processing unit of the dehumidifier.

[0103] The spectrum analysis module converts the noise digital signal X into a frequency domain signal X(f) in the central processing unit, 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 the reverse waveform generation mechanism and phase adjustment mechanism based on the time-varying noise power Snoise. After execution, it summarizes and calculates the output of the ultrasonic reverse waveform Pult, and controls the ultrasonic transmitter embedded in the dehumidifier to emit a reverse ultrasonic interference wave with the opposite frequency band to the noise.

[0105] The dynamic feedback adjustment module introduces a dynamic feedback mechanism after the reverse ultrasonic interference wave is emitted to calculate and output an ultrasonic signal adjustment amount ΔPult, thereby dynamically adjusting the ultrasonic signal and continuously optimizing the noise reduction effect.

[0106] The noise reduction effect evaluation module extracts the original noise and residual noise to calculate the ratio after the dynamic feedback mechanism is completed, outputs the residual noise ratio Rnoise, and evaluates the noise reduction effect based on the output result of the residual noise ratio Rnoise.

[0107] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention.

Claims

1. A method for noise reduction control in a dehumidifier, characterized in that, Includes the following steps: S1. Obtain the time-varying noise power Snoise during dehumidifier operation, and calculate the ultrasonic reverse waveform Pult based on the reverse waveform generation mechanism and phase adjustment mechanism; 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 adjust the gain adjustment factor using a digital signal processor (DSP) according to the time-varying nature of the noise power to control the output of the ultrasonic wave and obtain the ultrasonic signal amplitude; the phase adjustment mechanism includes basic phase adjustment and dynamic phase adjustment. The basic phase adjustment introduces a sinusoidal component, enabling the phase of the ultrasonic signal to adapt to changes in the nonlinear noise signal, maintaining the phase of the ultrasonic signal always opposite to that of the noise signal, and obtaining the basic phase term of the ultrasonic signal. The dynamic phase adjustment is achieved by calculating the time-varying noise power Snoise(f,t) and, based on the time-varying noise power Snoise(f,t) combined with a dynamic adjustment coefficient, calculating and outputting a dynamic phase adjustment term to adjust the phase of the ultrasonic signal. S2. Based on the ultrasonic reverse waveform Pult, control the ultrasonic transmitter embedded inside the dehumidifier to emit a reverse ultrasonic interference wave that is 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 ΔPult. S4. After the dynamic feedback mechanism is completed, the ratio of the original noise and the residual noise is extracted and calculated to obtain the residual noise ratio Rnoise. The noise reduction effect is evaluated based on the output of the residual noise ratio Rnoise. When the residual noise ratio Rnoise≤0, it indicates that the noise reduction adjustment is normal and no adjustment is needed; 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 stops.

2. The dehumidifier noise reduction control method according to claim 1, characterized in that, Prior to S1, the following are included: By installing noise sensors around the dehumidifier, the noise signals generated by the dehumidifier itself are collected in real time when the dehumidifier starts working. The noise sensors record the time of each noise signal collection to obtain the noise signal at time t. The noise sensor is connected to the central processing unit of the dehumidifier, and the noise signal collected in real time is transmitted to the central processing unit for processing to obtain the frequency domain signal X(f,t) at time t and frequency f.

3. The dehumidifier noise reduction control method according to claim 2, characterized in that, The step of transmitting the real-time acquired noise signal to the central processing unit for processing includes: After receiving the noise digital signal X in real time, the central processing unit marks the noise digital signal X with a timestamp 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 the frequency domain signal X(f,t) at time t and frequency f. The time-varying noise power Snoise is obtained by integrating the frequency domain signal X(f,t) at time t and frequency f.

4. The dehumidifier noise reduction control method according to claim 1, characterized in that, In S1, the calculation expression for the ultrasonic reverse waveform Pult is: ； In the formula, Pult(f,t) represents the reverse waveform of the ultrasonic wave at time t and frequency f; The amplitude of the ultrasonic signal is represented by ; k represents the gain adjustment factor; exp represents the exponential function with the natural constant e as the base; j represents the imaginary unit, which cancels out the ultrasonic signal when the phase of the ultrasonic signal is 180° opposite to that of the noise signal. Represents the linear phase adjustment coefficient; Represents the nonlinear phase correction coefficient; This represents the frequency factor of nonlinear oscillation; dSnoise(f,t) 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.

5. The dehumidifier noise reduction control method according to claim 4, 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 ΔPult, and the frequency and phase of the ultrasonic signal are dynamically adjusted based on the ultrasonic signal adjustment amount ΔPult.

6. The dehumidifier noise reduction control method according to claim 5, characterized in that, In step S4, the expression for the ultrasonic signal adjustment amount ΔPult is: ； In the formula, F1 represents the feedback gain coefficient; F2 represents the noise rate of change 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.

7. The dehumidifier noise reduction control method according to claim 5, characterized in that, In S1, the time-varying noise power Snoise(f,t) is expressed as: ； In the formula, T represents the length of the time-domain sliding window; dt represents the time calculus; tT represents the time interval from the past T seconds to the current time t; and X(f,t) represents the frequency domain signal at time t and frequency f.

8. A dehumidifier noise reduction control system, used to apply the dehumidifier noise reduction control method as described in any one of claims 1-7, characterized in that, include: The module includes 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. 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 processing unit of the dehumidifier. 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); The reverse ultrasonic waveform generation module is used to execute the reverse waveform generation mechanism and phase adjustment mechanism according to the time-varying noise power Snoise. After execution, it summarizes and calculates to output the ultrasonic reverse waveform Pult, and controls 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 adjustment amount ΔPult of the output ultrasonic signal, and dynamically adjust the ultrasonic signal to continuously optimize the noise reduction effect. The noise reduction effect evaluation module is used to extract the original noise and residual noise to calculate the ratio after the dynamic feedback mechanism is completed, 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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