Air source heat pump with active noise reduction function

Abstract

The invention provides an air source heat pump with an active noise reduction function, and belongs to the technical field of air source heat pumps, the air source heat pump can carry an active noise reduction module, the active noise reduction module is used for reducing low-frequency noise generated in the operation process of the air source heat pump, and hardware of the active noise reduction module is composed of an MCU, a DSP and other peripheral circuits. The MCU is responsible for reading the frequency of a fan and a compressor of a heat pump through a Modbus protocol and obtaining the fundamental frequency of noise, the MEMS noise microphone is used for collecting original noise, and the MEMS error microphone is used for collecting residual noise; the audio codec is used for converting analog signals collected by the MEMS microphone into digital signals and then sending the digital signals to the DSP, the DSP processes the collected signals through an FxLMS algorithm, noise reduction signals are obtained through integration and calculation, the audio codec and the power amplifier drive the secondary loudspeaker to output noise reduction sound waves with the phase opposite to that of noise, and the noise reduction sound waves are sent to the power amplifier. Noise reduction is realized through superposition of the noise reduction sound waves and the noise sound waves.

Description

Technical Field

[0001] The present invention belongs to the technical field of air source heat pumps, and more specifically, particularly relates to an air source heat pump with active noise reduction. Background Art

[0002] In the field of heating, ventilation and air conditioning, air source heat pumps, as a commonly used heating and cooling equipment, are widely used in various buildings, including residential, commercial buildings and other places, to facilitate users to obtain a suitable indoor temperature in different seasons. However, when the air source heat pumps on the market are operating, they will generate operating noise, and the noise mainly comes from the following aspects: compressors, fans, water pumps, airflow noise, refrigerant noise, control electromagnetic noise, etc. These noises may affect the surrounding environment and residents' lives in a quiet environment or at night. If effective noise reduction measures are not taken, it is easy to interfere with the normal rest and life of residents and have a negative impact on the quality of life of residents. To avoid this situation, special noise reduction devices will be used; however, the existing noise reduction measures of the existing devices usually reduce the fan speed, compressor operating frequency or add sound insulation materials, etc. to reduce the noise at the noise source or during the noise propagation process. However, these noise reduction measures have limited noise reduction effects on the dull and uncomfortable low-frequency noise received by the human ear. Summary of the Invention

[0003] In order to solve the above technical problems, the present invention provides an air source heat pump with active noise reduction to solve the technical problem that the existing devices in the prior art have limited noise reduction effects on low-frequency noise.

[0004] The purpose and efficacy of an air source heat pump with active noise reduction of the present invention are achieved by the following specific technical means:

[0005] An air source heat pump with active noise reduction, characterized in that it includes:

[0006] The main control of the air source heat pump, used to identify the current time and the ambient noise of the air source heat pump, and confirm whether to start the active noise reduction module;

[0007] The active noise reduction module, used to reduce the noise generated during the operation of the air source heat pump. The active noise reduction module is installed on the surface of the air source heat pump and is used to capture and process the noise signal of the air source heat pump.

[0008] The active noise reduction module includes multiple groups of MEMS noise microphones, multiple groups of MEMS error microphones, an audio decoder, a DSP, a power amplifier, multiple groups of secondary speakers and an MCU;

[0009] MEMS noise microphones, there are multiple groups of MEMS noise microphones. The multiple groups of MEMS noise microphones are distributed around the compressor housing, the fan blades, and the surface of the refrigerant pipeline, and are used to collect the original noise. The MEMS noise microphones output the environmental noise to the audio decoder;

[0010] MEMS error microphones, multiple groups of MEMS error microphones are respectively arranged on one side of multiple groups of MEMS noise microphones, and are used to collect the residual noise after noise reduction by the noise reduction module. The MEMS microphones transmit the residual noise to the audio decoder;

[0011] Audio decoder, the audio codec can convert the analog signals transmitted by the MEMS noise microphones and the MEMS error microphones into digital signals that can be processed by the DSP. Then, the noise reduction signal obtained after DSP processing is converted back into an analog signal and broadcast by the secondary speaker driven by the power amplifier:

[0012] DSP, the DSP stores the data of the noise, processes the collected signals using the FxLMS algorithm, and obtains a noise reduction signal with a phase opposite to that of the noise;

[0013] Power amplifier, the power amplifier amplifies the low-power noise reduction signal transmitted by the audio codec to a high-power signal that can drive the secondary speaker;

[0014] Secondary speaker, converts the noise reduction signal into physical sound waves;

[0015] MCU, the MCU is responsible for communicating with the heat pump main control through the Modbus protocol. The MCU can obtain the compressor frequency and fan frequency of the heat pump, and analyze the fundamental frequency of the noise for the active noise reduction system; at the same time, the heat pump main control can obtain the noise data in the MCU.

[0016] As a further solution of the present invention, the following noise reduction steps are included:

[0017] S101: Obtain the noise in the environment through the MEMS noise microphone, convert it into a noise signal and transmit it to S102;

[0018] S1011: Collect the residual noise after noise reduction by the noise reduction module through the MEMS error microphone, convert the residual noise into an error signal through the audio codec, transmit the error signal to the DSP, and the DSP updates the algorithm weight and then transmits it to S105;

[0019] S102: Based on the environmental noise obtained by the MEMS noise microphone, receive and process the environmental noise through the audio codec. The audio codec samples and quantifies the noise signal, converts the noise signal from an analog signal to a digital signal, and transmits the digital signal data to S103.

[0020] S103: The DSP calculates the noise reduction signal based on the digital signal through the FxLMS algorithm. After the noise reduction signal is converted from the digital signal to an analog signal by the audio decoder, it is transmitted to S104;

[0021] S104: Based on the analog signal, the secondary speaker is driven by the power amplifier to play the noise reduction sound wave, which is superimposed and cancelled with the noise sound wave in the environment. At the same time, the noise reduction sound wave data is transmitted to S105;

[0022] S105: Adjust the FxLMS weight coefficient according to the error signal, and then the DSP generates the adjusted noise reduction signal again.

[0023] As a further solution of the present invention, the formula for calculating the noise reduction signal is:

[0024]

[0025] where y(n) is the noise reduction signal, x(n) is the noise reference signal, wi(n) is the i-th filter weight coefficient, representing the weight of the filter at time n, x(n - i) is the delayed version of the reference signal x(n), representing the historical values of the input signal at different time points, and M is the order of the filter.

[0026] As a further solution of the present invention, the formula for calculating the error signal is:

[0027] e(n) = d(n) - y(n)

[0028] where d(n) is the original noise signal, y(n) is the noise reduction signal, and e(n) is the residual noise signal representing the error after noise reduction.

[0029] As a further solution of the present invention, the formula for updating the FxLMS weight coefficient is:

[0030] w i (n + 1) = w i (n) + μ·e(n)·x(n - i);

[0031] wi(n) is the value of the i-th filter weight coefficient at time n, μ is the step factor, which determines the rate of weight update and usually needs to be adjusted to ensure convergence, e(n) is the error signal at the current moment, and x(n - i) is the value of the reference signal x(n) at the delayed i-th moment.

[0032] As a further solution of the present invention, the audio codec receives and processes the noise sent back by the MEMS noise microphone, samples and quantifies the noise to obtain noise signals such as the frequency, amplitude, and phase of white noise in the frequency band of 50 - 500 Hz, transmits the data to the DSP, the DSP converts the noise signal into a noise reduction signal based on the FxLms algorithm, the audio codec module converts the noise reduction signal from a digital signal into an analog signal, amplifies the power of the noise reduction signal by a power amplifier, and then the secondary speaker plays the noise reduction wave, which is superposed with the environmental noise wave.

[0033] As a further solution of the present invention, the audio codec samples and quantifies the residual noise after noise reduction collected by the MEMS error microphone, converts it into an error signal and transmits it to the DSP, and based on the error signal, the DSP adjusts the amplitude, phase, and frequency of the noise reduction signal through an algorithm to adjust the noise reduction signal.

[0034] As a further solution of the present invention, the active noise reduction module uses the standard ModbusRTU protocol for data transmission based on RS485 communication. The MCU obtains the working state of the heat pump in real time, receives the current compressor frequency and fan frequency of the heat pump through the 485 communication interface, calculates the noise corresponding to the working frequency, and the main control of the heat pump can also read the decibel data in the active noise reduction module.

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

[0036] First, the present invention provides an active noise reduction module. Users can independently choose whether to install this module on the air source heat pump according to actual needs. Compared with the existing devices that rely on sound insulation materials for noise reduction, by setting up the active noise reduction module, the air source heat pump does not need to add additional sound insulation materials, effectively avoiding the problems of increased air conditioner volume and weight caused by adding sound insulation materials, and reducing the installation and maintenance costs of the equipment. Secondly, the existing physical sound insulation materials have limited means for reducing the noise in the lower frequency band of 50 - 500 Hz generated during the operation of the compressor and fan of the air source heat pump. The active noise reduction module of the present invention can effectively process the noise in the lower frequency band of 50 - 500 Hz. When the main control of the air source heat pump recognizes the environmental noise in the lower frequency band of 50 - 500 Hz through real-time monitoring of the surrounding environment noise, it will automatically activate the active noise reduction module. During the operation of the active noise reduction module, multiple groups of MEMS noise microphones distributed around the compressor housing, fan blades, and the surface of the refrigerant pipeline can collect the original noise and convert it into a noise signal for transmission to the audio decoder. At the same time, multiple groups of MEMS error microphones located on one side of the MEMS noise microphones will synchronously collect the residual noise after noise reduction by the noise reduction module and convert it into an error signal for transmission to the audio decoder. The audio codec can convert the analog signals from the MEMS noise microphones and MEMS error microphones into digital signals for transmission to the DSP. As the core processing unit of the active noise reduction module, the DSP performs real-time analysis and processing based on the received digital signals using the FxLMS algorithm. Through the analysis of the digital signals, the DSP can generate a noise reduction signal corresponding to the noise. Subsequently, this noise reduction signal is converted into an analog signal by the audio decoder, and the power amplifier amplifies the low-power analog signal transmitted by the audio codec into a high-power signal capable of driving the secondary speaker. Finally, the secondary speaker converts the high-power signal into physical sound waves, and the noise reduction sound waves are superimposed and cancelled with the noise sound waves in the environment, thereby reducing the noise generated during the operation of the compressor and fan of the air source heat pump, improving the user experience, and enhancing the comfort of the user during residence. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 is a schematic structural diagram of the present invention;

[0038] Figure 2 is a schematic block diagram of the principle of the present invention;

[0039] Figure 3 is a schematic structural diagram of the active noise reduction module of the present invention;

[0040] Figure 4 is a schematic diagram of the active noise reduction module of the present invention;

[0041] Figure 5 is a flowchart of the steps of the present invention. Detailed implementation mode

[0042] The following further describes the implementation mode of the present invention in detail in conjunction with the drawings and embodiments. The following embodiments are used to illustrate the technical solutions of the present invention, but cannot be used to limit the protection scope of the present invention.

[0043] Embodiment:

[0044] As Figures 1 to 5 shown:

[0045] The present invention provides an air source heat pump with active noise reduction, including:

[0046] The main control of the air source heat pump is used to identify the current time and the ambient noise of the air source heat pump, confirm whether to start the active noise reduction module, and trigger the start mechanism of the active noise reduction module by monitoring and analyzing the time and ambient noise parameters, so as to effectively reduce the noise impact when the air source heat pump operates in noise-sensitive time periods or areas;

[0047] The active noise reduction module is used to reduce the noise generated during the operation of the air source heat pump. The active noise reduction module is installed on the surface of the air source heat pump and is used to capture and process the noise signal of the air source heat pump.

[0048] The active noise reduction module includes multiple groups of MEMS noise microphones, multiple groups of MEMS error microphones, an audio decoder, a DSP, a power amplifier, multiple groups of secondary speakers, and an MCU;

[0049] MEMS noise microphones, multiple groups of MEMS noise microphones are provided, and the multiple groups of MEMS noise microphones are distributed around the compressor housing, the fan blades, and the surface of the refrigerant pipeline, and are used to collect the original noise. Based on the collected ambient noise, the MEMS noise microphones output the ambient noise to the audio decoder;

[0050] MEMS error microphones, multiple groups of MEMS noise microphones are respectively arranged on one side of the multiple groups of MEMS noise microphones, and are used to collect the residual noise after the noise reduction module reduces the noise. The MEMS noise microphones transmit the residual noise to the audio decoder, and the audio decoder provides feedback information for the DSP, so that the DSP can adjust the noise reduction strategy and optimize the noise reduction effect;

[0051] DSP, the DSP stores the data of the noise, processes the collected signal using the FxLMS algorithm, and obtains a noise reduction signal with a phase opposite to that of the noise. The DSP extracts and analyzes the characteristics of the noise signal based on the FxLms algorithm to generate a noise reduction signal matching the noise characteristics, improve the noise reduction efficiency, and enhance the reliability of the device;

[0052] Furthermore, the DSP deeply processes and converts the input noise signal based on the FxLms algorithm. By continuously adjusting the weight coefficients of the filter through the FxLms algorithm, the generated noise reduction signal cancels out the original noise signal as much as possible, thereby achieving the purpose of noise reduction and enhancing the practicality of the device.

[0053] Furthermore, the DSP adjusts the amplitude, phase, and frequency of the noise reduction signal based on the error signal through an algorithm for noise reduction signal adjustment. When the DSP receives the error signal, it will analyze the characteristics of the error signal according to the preset algorithm rules, judge the deviation between the current noise reduction signal and the ideal state, and the DSP will adjust the amplitude and phase of the noise reduction signal through the algorithm to make the phase of the noise reduction signal better match the original noise, enabling the DSP to continuously optimize the noise reduction signal to adapt to possible changes in the noise characteristics during the operation of the air source heat pump, ensuring that the device can maintain a good noise reduction effect under various working conditions, and effectively enhancing the performance and stability of the active noise reduction module.

[0054] Audio decoder. The audio codec can convert the analog signal transmitted from the microphone into a digital signal that can be processed by the DSP. Then, after the DSP processes it to obtain the noise reduction signal, the audio decoder converts the noise reduction signal back into an analog signal and transmits it to the power amplifier:

[0055] Power amplifier. The power amplifier amplifies the low-power noise reduction signal transmitted from the audio codec to a high-power signal that can drive the secondary speaker;

[0056] Secondary speaker. The secondary speaker is used to receive the noise reduction signal, convert the noise reduction signal into a physical noise reduction sound wave. Based on the interrelationship between the noise reduction sound wave and the environmental noise, when the noise reduction sound wave is superimposed with the environmental noise, according to the principle of wave interference, the intensity of the environmental noise can be effectively reduced, achieving the purpose of active noise reduction;

[0057] Furthermore, the noise reduction signal is converted into an audio signal by the audio decoder, and the power amplifier drives the secondary speaker to play the noise reduction sound wave. The noise reduction sound wave propagates in the air and overlaps with the environmental noise sound wave generated by the air source heat pump. Through the principle of wave superposition, the two interfere with each other, reducing the amplitude of the synthesized sound wave, thereby achieving the effect of reducing environmental noise.

[0058] MCU. The MCU is responsible for communicating with the heat pump main control through the Modbus protocol. The MCU can obtain the compressor frequency and fan frequency of the heat pump, and analyze the fundamental frequency of the noise for the active noise reduction system; the heat pump main control can obtain the noise data in the MCU;

[0059] Furthermore, the audio codec obtains the noise frequency, phase, and amplitude data based on the noise collected by the MEMS noise microphone and the MEMS error microphone, and then outputs these data to the DSP. The active noise reduction module uses the standard ModbusRTU protocol for data transmission based on RS485 communication. The MCU obtains the working status of the heat pump in real time, receives the current compressor frequency and fan frequency of the heat pump through the 485 communication interface, and calculates the noise corresponding to the working frequency. The heat pump main control can also read the decibel data in the active noise reduction module. These decibel data reflect the current environmental noise level and the effect of noise reduction processing, providing a key basis for the system to further optimize the noise reduction strategy and adjust the working parameters in real time, thereby ensuring that the active noise reduction module is always in an efficient operating state and effectively reducing the noise generated by the air source heat pump.

[0060] The specific noise reduction steps include:

[0061] S101: The noise in the environment is acquired through the MEMS noise microphone, and converted into a noise signal and transmitted to the corresponding audio codec of S102. By setting up multiple sets of MEMS noise microphones, the rapid and accurate acquisition and preliminary conversion of the environmental noise are ensured;

[0062] S1011: The residual noise after the noise reduction module has been used for noise reduction is collected through a MEMS error microphone, and the residual noise is converted into an error signal through audio codec, and the error signal is transmitted to the DSP, and the DSP updates the algorithm weights and then transmits them to S105;

[0063] Furthermore, the formula for calculating the error signal is:

[0064] e(n)=d(n)-y(n)

[0065] Among them, d(n) is the original noise signal, y(n) is the noise reduction signal, and e(n) is the residual noise signal, that is, the error after noise reduction. Through this formula, DSP can quantify the deviation between the noise reduction effect and the ideal state, and then adjust the noise reduction algorithm in a targeted manner.

[0066] S102: Based on the environmental noise obtained by the MEMS noise microphone, the environmental noise is received and processed through the audio codec. The audio codec samples and quantizes the noise signal, converts the noise signal from an analog signal to a digital signal, and transmits the processed noise signal data to the DSP corresponding to S103. S102 standardizes the noise signal to provide a data basis for the subsequent DSP to calculate the noise reduction signal.

[0067] S103: Based on the noise signal received and processed by the audio codec, the DSP calculates the noise reduction signal based on the FxLMS algorithm, converts it into an analog signal through the audio decoder, transmits the analog signal to the power amplifier, amplifies the analog signal into a high-power signal through the power amplifier, and transmits the high-power signal to S104;

[0068] Further, the formula for calculating the noise reduction signal is:

[0069]

[0070] where y(n) is the noise reduction signal, x(n) is the noise reference signal, wi(n) is the weight coefficient of the i-th filter, representing the weight of the filter at time n, x(n-i) is the delayed version of the reference signal x(n), representing the historical values of the input signal at different time points, and M is the order of the filter. This formula generates a noise reduction signal that matches the noise characteristics through time-domain analysis and processing of the noise signal, achieving effective suppression of noise.

[0071] S104: Based on the high-power signal of the power amplifier, the secondary speaker plays the noise reduction wave, which is superimposed and cancelled with the noise wave in the environment. At the same time, the noise reduction wave data is transmitted to S105; this provides a basis for subsequent adjustment of the noise reduction signal. This step directly acts on the environmental noise and reduces the environmental noise intensity through the superimposition and cancellation of sound waves.

[0072] S105: Adjust the FxLMS weight coefficient according to the error signal, and then the DSP generates the adjusted noise reduction signal.

[0073] Further, the formula for updating the FxLMS weight coefficient is:

[0074] w i (n + 1) = w i (n) + μ·e(n)·x(n - i);

[0075] wi(n) is the value of the weight coefficient of the i-th filter at time n, μ is the step factor, which determines the rate of weight update and usually needs to be adjusted to ensure convergence. e(n) is the error signal at the current time, and x(n - i) is the value of the reference signal x(n) at the delayed i-th time. By continuously adjusting the weight coefficient, the DSP makes the noise reduction signal match the noise signal better, continuously optimizing the noise reduction effect and ensuring a low noise level during the operation of the air source heat pump.

[0076] The specific usage method and function of this implementation:

[0077] During the daily operation of the air-source heat pump, first, multiple groups of MEMS noise microphones distributed around the compressor housing, the fan blades, and the surface of the refrigerant pipeline start to work, collecting the original noise in the surrounding environment and transmitting it to the audio decoder. At the same time, the MEMS error microphone located on one side of the MEMS noise microphone will collect the residual noise after being processed by the noise reduction module and transmit it to the audio decoder. The audio decoder samples and quantifies the noise and the residual noise, converts the original noise and the residual noise from analog signals to digital signals, and then transmits them to the DSP. After receiving the digital signals from the audio decoder, the DSP processes and analyzes the digital signals based on the FxLms algorithm. By adjusting the weight coefficients of the filter, it extracts the digital signal features and generates the corresponding noise reduction signal. Subsequently, the noise reduction signal is transmitted to the audio decoder, and the audio decoder decodes the noise reduction signal, converts the noise reduction signal from a digital signal to an analog signal and transmits it to the power amplifier. Then, the power amplifier drives the secondary speaker to play the noise reduction wave, which is superimposed and cancelled with the noise wave in the environment. According to the principle of wave interference, the intensity of the environmental noise is effectively reduced to achieve the purpose of active noise reduction. At the same time, the DSP adjusts the FxLMS weight coefficients according to the error signal, and then the DSP generates the adjusted noise reduction signal again to optimize the noise reduction strategy, ensuring that a good noise reduction effect can be maintained during the operation of the air-source heat pump. The active noise reduction module uses the standard ModbusRTU protocol for data transmission based on RS485 communication. The heat pump main control sends the working state of the heat pump to the active noise reduction module to ensure that all parts of the system monitor the operation status of the heat pump in real time. The active noise reduction module receives the current compressor frequency and fan frequency of the heat pump through the 485 communication interface, and calculates the corresponding noise situation at this working frequency based on the real-time frequency data using the built-in algorithm. In addition, the heat pump main control can read the decibel data of the active noise reduction module, and reflect the current environmental noise level and the effect after noise reduction processing through the decibel data.

[0078] The above-described embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included in the protection scope of the present invention.

Claims

1. An air source heat pump with active noise reduction, characterized in that, Comprising: An air source heat pump main controller, which is used to identify the current time and the ambient noise of the air source heat pump, and confirm whether to activate the active noise reduction module; An active noise reduction module, which is used to reduce the noise generated during the operation of the air source heat pump. The active noise reduction module is installed on the surface of the air source heat pump and is used to capture and process the noise signal of the air source heat pump. The active noise reduction module includes multiple groups of MEMS noise microphones, multiple groups of MEMS error microphones, an audio decoder, a DSP, a power amplifier, multiple groups of secondary speakers, and an MCU; MEMS noise microphones, with multiple groups of MEMS noise microphones set up. The multiple groups of MEMS noise microphones are distributed around the compressor housing, the fan blades, and the surface of the refrigerant pipeline, and are used to collect the original noise. The MEMS noise microphones output the ambient noise to the audio decoder; MEMS error microphones, with multiple groups of MEMS error microphones respectively set on one side of the multiple groups of MEMS noise microphones, and are used to collect the residual noise after the noise reduction module reduces the noise. The MEMS noise microphones transmit the residual noise to the audio decoder; The audio decoder can convert the analog signals transmitted by the MEMS noise microphones and the MEMS error microphones into digital signals that can be processed by the DSP. Then, the noise reduction signal obtained after the DSP processes it is converted back into an analog signal and broadcast by the secondary speakers driven by the power amplifier: The DSP stores the data of the noise, uses the FxLMS algorithm to process the collected signals, and obtains a noise reduction signal with a phase opposite to that of the noise; The power amplifier amplifies the low-power noise reduction signal transmitted by the audio codec to a high-power signal capable of driving the secondary speakers; The secondary speakers convert the noise reduction signal into physical sound waves; The MCU is responsible for communicating with the heat pump main controller through the Modbus protocol. The MCU can obtain the compressor frequency and the fan frequency of the heat pump, and analyze the fundamental frequency of the noise for the active noise reduction system; at the same time, the heat pump main controller can obtain the noise data in the MCU.

2. The air source heat pump with active noise reduction according to claim 1, characterized in that, Including the following noise reduction steps: S101: Obtain the noise in the environment through the MEMS noise microphones, convert it into a noise signal, and transmit it to S102; S1011: Collect the residual noise after the noise reduction module reduces the noise through the MEMS error microphones, convert the residual noise into an error signal through the audio codec, transmit the error signal to the DSP, and after the DSP updates the algorithm weights, transmit it to S105; S102: Based on the ambient noise obtained by the MEMS noise microphones, receive and process the ambient noise through the audio codec. The audio codec samples and quantifies the noise signal, converts the noise signal from an analog signal to a digital signal, and transmits the digital signal data to S103; S103: The DSP calculates the noise reduction signal based on the digital signal through the FxLMS algorithm. The noise reduction signal is converted from a digital signal to an analog signal by the audio decoder and then transmitted to S104; S104: Based on the analog signal, drive the secondary speakers to play the noise reduction sound waves through the power amplifier, superimpose and cancel them with the noise sound waves in the environment, and at the same time transmit the noise reduction sound wave data to S105; S105: Adjust the FxLMS weight coefficients according to the error signal, and then the DSP generates the adjusted noise reduction signal.

3. The air source heat pump with active noise reduction according to claim 2, characterized in that, The calculation formula for the noise reduction signal is: Among them, y(n) is the noise reduction signal, x(n) is the noise reference signal, wi(n) is the weight coefficient of the i-th filter, representing the weight of the filter at time n, x(n-i) is the delayed version of the reference signal x(n), representing the historical values of the input signal at different time points, and M is the order of the filter.

4. The air source heat pump with active noise reduction according to claim 2, characterized in that, The formula for calculating the error signal is: e(n) = d(n) - y(n) Among them, d(n) is the original noise signal, y(n) is the noise reduction signal, and e(n) is the residual noise signal representing the error after noise reduction.

5. The air source heat pump with active noise reduction according to claim 2, characterized in that, The formula for updating the FxLMS weight coefficients is: wi (n + 1) = wi (n) + μ·e(n)·x(n - i); wi(n) is the value of the weight coefficient of the i-th filter at time n, μ is the step factor, which determines the rate of weight update and usually needs to be adjusted to ensure convergence, e(n) is the error signal at the current moment, and x(n-i) is the value of the reference signal x(n) at the time delayed by i moments.

6. The air source heat pump with active noise reduction according to claim 2, characterized in that: Receive and process the noise sent back by the MEMS noise microphone through the audio codec, sample and quantize the noise to obtain noise signals such as the frequency, amplitude, and phase of white noise in the frequency band of 50 - 500 Hz, transmit the data to the DSP, the DSP converts the noise signal into a noise reduction signal based on the FxLms algorithm, the audio codec module converts the noise reduction signal from a digital signal to an analog signal, amplifies the power of the noise reduction signal by the power amplifier, and then the secondary speaker plays the noise reduction wave, which is superimposed with the environmental noise wave.

7. The air source heat pump with active noise reduction according to claim 2, characterized in that: The audio codec samples and quantizes the residual noise after noise reduction collected by the MEMS error microphone, converts it into an error signal and transmits it to the DSP, and the DSP adjusts the amplitude, phase, and frequency of the noise reduction signal through an algorithm based on the error signal for noise reduction signal adjustment.

8. The air source heat pump with active noise reduction according to claim 1, characterized in that: The active noise reduction module uses the standard ModbusRTU protocol for data transmission based on RS485 communication. The MCU obtains the working status of the heat pump in real time, receives the current compressor frequency and fan frequency of the heat pump through the 485 communication interface, calculates the noise corresponding to this working frequency, and the main control of the heat pump can also read the decibel data in the active noise reduction module.

Images