CN117628558A - Active control device and noise reduction method for noise of multi-channel smoke exhaust ventilator - Google Patents
Active control device and noise reduction method for noise of multi-channel smoke exhaust ventilator Download PDFInfo
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- 239000000779 smoke Substances 0.000 title claims abstract description 61
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24C—DOMESTIC STOVES OR RANGES ; DETAILS OF DOMESTIC STOVES OR RANGES, OF GENERAL APPLICATION
- F24C15/00—Details
- F24C15/20—Removing cooking fumes
- F24C15/2021—Arrangement or mounting of control or safety systems
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- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
- G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/175—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound
- G10K11/178—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound by electro-acoustically regenerating the original acoustic waves in anti-phase
- G10K11/1785—Methods, e.g. algorithms; Devices
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B30/00—Energy efficient heating, ventilation or air conditioning [HVAC]
- Y02B30/70—Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating
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Abstract
The utility model discloses a multichannel smoke ventilator noise active control device and a noise reduction method, wherein the multichannel smoke ventilator noise active control device comprises a rotating speed sensor arranged on a turbofan of a smoke ventilator, a first microphone arranged at an air outlet at the upper end of the smoke ventilator, a second microphone arranged at an air inlet of the smoke ventilator and close to the turbofan, a third microphone arranged right below the air inlet of the smoke ventilator, a rotating speed meter arranged on a turbofan shaft, a first loudspeaker arranged in an inclined tube forming an angle of 45 degrees with an air outlet tube of the smoke ventilator, a second loudspeaker and a third loudspeaker symmetrically arranged at the inner side of an air inlet cover of the smoke ventilator and pointing to the third microphone, and a controller arranged on the right side wall of the smoke ventilator. Comprehensively considering the noise generation mechanism of the smoke exhaust ventilator, the noise types under different operation conditions, the arrangement of noise control devices and the like, the potential of the noise reduction system is fully exerted, and the rapid, stable and effective control of the noise under the different operation conditions of the smoke exhaust ventilator is realized.
Description
Technical Field
The utility model relates to the technical field of multichannel active noise control systems, in particular to a multichannel smoke exhaust ventilator noise active control device and a noise reduction method.
Background
In the use process of the range hood, the range hood needs to be exhausted from a space area below the range hood, and in the range hood oil exhausting process, flowing air rubs with an air inlet grille, rubs with a turbine fan blade and generates strong noise in an air outlet pipeline, so that the noise not only affects language communication in the cooking process, but also can generate great harm to hearing of people. Most existing range hoods weaken noise when the range hoods work by arranging sound absorption structures, arranging sound absorption materials and the like and adopting a passive noise reduction method, however, the method is only effective for controlling high-frequency noise and has poor effect for controlling low-frequency noise. The active noise control technology can make up for the defect of passive noise reduction.
The utility model discloses an active noise reduction system of a smoke exhaust ventilator and a sealing device thereof, and provides the active noise reduction system of the smoke exhaust ventilator, which seals active noise reduction system components in a detachable closed space by using an oil-proof sound-transmitting film aiming at the problem of serious greasy dirt in the running environment of the existing active noise reduction system of the smoke exhaust ventilator. The active noise reduction system has the advantages of keeping the components of the active noise reduction system in a good working environment, prolonging the service life of the active noise reduction system, and ensuring that the sealing device is of a detachable structure, so that a user can conveniently detach and wash the sealing device. However, the active noise reduction scheme also has adaptability to the range hood under different operation conditions and different rotation speeds of the turbofan, and has limited noise reduction performance.
Chinese patent No. CN217280023U discloses an active noise reducing device for range hood with adjustable positions of noise pickup part and speaker part, which can achieve optimal noise control by adjusting the positions of the noise pickup part and speaker part under different operating conditions of the range hood. However, the device has the following defects: firstly, the position adjustable mechanism provided by the utility model occupies a larger space and is difficult to combine with the smoke exhaust ventilator body; secondly, the device provided by the utility model needs to manually adjust the positions of the noise pickup component and the loudspeaker component, and the operation is too complex; thirdly, the noise active noise reduction device lacks noise reduction on the air outlet of the smoke exhaust ventilator, and the overall active noise reduction effect is not ideal.
Therefore, the prior art has the defects that the active noise reduction noise source is single in control, the noise at the air inlet is mainly actively controlled, the attention to the noise at the air outlet is lacked, and the noise is changed along with the change of the operation condition of the range hood, but the existing active control algorithm is difficult to adjust in time, so that the overall noise control effect of the range hood is not ideal, and a new active noise reduction method is needed to solve the problems.
Disclosure of Invention
In view of the above, the present utility model aims to provide a multi-channel smoke exhaust ventilator noise active control device and a noise reduction method, which combine the technologies of a narrow-band ANC algorithm, a wide-band ANC algorithm and noise classification based on the rotation speed of a turbofan, have good noise control effects on the smoke exhaust ventilator, and reduce the influence of noise of the smoke exhaust ventilator on users in the use process.
In order to achieve the above purpose, the utility model adopts the following technical scheme: the multichannel smoke ventilator noise active control device comprises a rotation speed sensor arranged on a smoke ventilator turbofan, a first noise pickup microphone arranged at an air outlet at the upper end of the smoke ventilator, a second noise pickup microphone arranged at an air inlet of the smoke ventilator and close to the turbofan, a third noise pickup microphone arranged right below the air inlet of the smoke ventilator, a first loudspeaker component arranged in an inclined pipe forming an angle of 45 degrees with an air outlet pipe of the smoke ventilator, a second loudspeaker component and a third loudspeaker component symmetrically arranged at the inner side of the air inlet cover of the smoke ventilator and pointing to the third noise pickup microphone, and a controller arranged on the right side wall of the smoke ventilator; the rotating speed sensor, the first noise pickup microphone, the second noise pickup microphone, the third noise pickup microphone, the first loudspeaker component, the second loudspeaker component and the third loudspeaker component are all connected with the controller through wires.
In a preferred embodiment, the first noise pickup microphone comprises a microphone for picking up noise at the outlet of the outlet duct of the range hood.
In a preferred embodiment, the second noise pickup microphone comprises a microphone for picking up noise generated by the range hood at the range hood intake grill.
In a preferred embodiment, the third noise pickup microphone comprises a microphone for picking up noise directly under the range hood, and is only used in the stage of identifying the second and third transfer functions and pre-training to obtain the < rotation speed and the filter parameter >, and the range hood is removed when the range hood is put into use.
In a preferred embodiment, the speed sensor includes a hall speed sensor for measuring the rotational speed of the turbofan.
In a preferred embodiment, the first speaker unit is mounted in a chute connected to the outlet duct for generating an anti-noise signal.
In a preferred embodiment, the second and third speaker units are configured to generate anti-noise signals at the air intake.
The utility model also provides a noise reduction method of the multichannel smoke exhaust ventilator noise active control device, which adopts the multichannel smoke exhaust ventilator noise active control device; the method comprises the following steps:
keeping other speakers inactive, driving the first speaker to emit white noise by the controller, picking up the white noise emitted by the speaker by the first microphone, and identifying a first transfer function from the first speaker to the first microphone;
keeping other speakers inactive, driving the second speaker to emit white noise by the controller, picking up the white noise emitted by the speaker by the third microphone, and identifying a second transfer function from the second speaker to the third microphone;
keeping other speakers inactive, driving a third speaker to emit white noise by the controller, picking up the white noise emitted by the speaker by a third microphone, and identifying a third transfer function from the third speaker to the third microphone;
keeping the first loudspeaker not working, and normally working the range hood, the first loudspeaker and the second loudspeaker, and adjusting the range hood to be at different rotating speeds to obtain corresponding controller parameters at different rotating speeds;
the range hood, all the loudspeakers and the microphones are operated, and the first ANC system uses a narrow-band adaptive filter to actively reduce noise to control the first loudspeaker to generate anti-noise so as to control noise at the air outlet of the range hood; the second ANC system judges the current rotation speed of the smoke exhaust ventilator once every 0.5-1 second and selects a group of corresponding filter parameters, so that the controller outputs two groups of anti-noise signals to drive the second loudspeaker and the third loudspeaker to emit anti-noise to control the noise of the space around the third microphone.
In a preferred embodiment, the system recognition algorithm used by the first transfer function, the second transfer function and the third transfer function is a least mean square algorithm LMS, the speaker driving signal is generated by the controller and is used as the input of the transfer function, and the signals collected by the first microphone and the third microphone are used as the output of the transfer function; the corresponding controller parameters at different rotating speeds are a matrix of 2 rows, and each row respectively controls the second loudspeaker and the third loudspeaker; the noise classification method based on the rotating speed equally divides the range hood from the lowest rotating speed to the highest rotating speed into 300 stages, the < rotating speed and filter parameter > pair corresponding to each stage is required to be pre-trained through an FxLMS algorithm before the range hood is formally put into use, and the filter parameter corresponding to the rotating speed stage closest to the current rotating speed is selected as the parameter of a fixed parameter filter when the range hood is formally put into use, so that a loudspeaker driving signal is generated.
In a preferred embodiment, the method further comprises:
the first ANC system is a narrow-band ANC system, and an algorithm used by a controller is an adaptive notch FxLMS algorithm; the algorithm used by the second ANC system is a fixed parameter filter active noise reduction algorithm capable of updating the filter parameters regularly, and the filter parameters are updated according to the operation working condition of the smoke exhaust ventilator.
Compared with the prior art, the utility model at least comprises the following beneficial effects:
the utility model aims at two main noise sources of the smoke exhaust ventilator, uses a narrow-band active noise reduction technology based on a notch FxLMS algorithm for an air outlet pipeline, uses a broadband active noise reduction technology for noise at an air inlet, and organically combines a noise classification method based on the rotating speed of a turbofan with a fixed filter selection technology. The fixed filter selection technique selects a pre-trained set of filter parameters based on the turbofan rotational speed and filters the source noise of the input system to produce a speaker drive signal.
The active noise reduction system for the smoke exhaust ventilator provided by the utility model actively controls two main noise sources of noise at the air inlet and the air outlet pipeline of the smoke exhaust ventilator, and can effectively reduce the noise generated by the whole smoke exhaust ventilator. Meanwhile, the adaptive notch FxLMS algorithm with only 2 adjustable parameters is used for active noise reduction at the air outlet pipeline, so that the noise of the air outlet pipeline is effectively inhibited, and meanwhile, the calculation complexity of the algorithm is greatly reduced. In addition, noise at the air inlet is actively controlled by selecting the optimal filter parameters according to the rotating speed of the fan, the filter parameters do not need to be adaptively adjusted, the effective noise reduction is realized, meanwhile, the calculation complexity is greatly reduced, the robustness of the noise reduction system is enhanced, the algorithm convergence process is omitted, and the tracking capability of the active noise reduction system to noise changes is enhanced. The noise active control system which mixes the wide and narrow bands and introduces noise classification can greatly inhibit noise generated in the operation of the smoke exhaust ventilator, and has wide application prospect and commercial value.
Drawings
Fig. 1 is a schematic view of the device arrangement structure of a range hood according to a preferred embodiment of the present utility model;
FIG. 2 is a schematic diagram of the hardware connections of a preferred embodiment of the present utility model;
FIG. 3 is a block diagram of a noise control system implementation and workflow in accordance with a preferred embodiment of the present utility model;
FIG. 4 is a schematic diagram of transfer function identification in accordance with a preferred embodiment of the present utility model;
FIG. 5 is a control block diagram of a second ANC system in accordance with a preferred embodiment of the present utility model;
FIG. 6 is a control block diagram of a first ANC system in accordance with a preferred embodiment of the present utility model.
Detailed Description
The utility model will be further described with reference to the accompanying drawings and examples.
It should be noted that the following detailed description is illustrative and is intended to provide further explanation of the present application. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.
It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments in accordance with the present application; as used herein, the singular is also intended to include the plural unless the context clearly indicates otherwise, and furthermore, it is to be understood that the terms "comprises" and/or "comprising" when used in this specification are taken to specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof.
Fig. 1 is a layout diagram of an ANC system device of a range hood according to an embodiment of the present utility model. As shown in fig. 1, the active noise reduction device of the range hood provided in this embodiment includes a first ANC system device and a second ANC system device. Wherein first ANC system device is including installing the first microphone 10 in smoke ventilator air-out pipeline department, including installing the first speaker 20 in the pipeline that connects with smoke ventilator air-out pipeline in the scarf, including installing the tachometer 30 near the turbofan axle, including installing the controller 80 on smoke ventilator right side wall, first microphone 10, first speaker 20, tachometer 30 all are connected with controller 80. Wherein the second ANC system means comprises a second microphone 40 mounted at the intake grill of the range hood; including a third microphone 60 mounted directly below the range hood; comprises a second loudspeaker 50 and a third loudspeaker 70 which are arranged on the inner side wall of an air inlet cover of the smoke exhaust ventilator; including a controller 80 shared with the first ANC system; the second microphone 40, the third microphone 60, the second speaker 50, and the third speaker 70 are all connected to the controller 80.
The first microphone 10 is used for picking up the residual noise at the air outlet pipe of the range hood, the second microphone 40 is used for picking up the noise at the air inlet grille of the range hood and is used as an input signal of a controller, and the third microphone 60 is used for picking up the residual noise of the noise control area below the air inlet grille of the range hood.
The tachometer 30 is used to measure the rotational speed of the turbofan to provide a control input signal to the first ANC system.
The first speaker 20 is used to generate anti-noise near the first microphone at the hood air outlet, and the second speaker 50 and the third speaker 70 are used to generate anti-noise in the noise control area below the hood air inlet grille.
The controller 80 is configured to collect 3 microphone signals and 1 rotational speed sensor signals, operate control algorithms of the first ANC system and the second ANC system, select controller parameters according to the turbofan rotational speed signals, and generate 3 speaker driving signals.
For the active noise reduction device of the smoke exhaust ventilator, as shown in fig. 2, the controller comprises a rotating speed acquisition module, an ADC module, a numerical calculation module and a DAC module. The ADC module is used for converting the acquired input noise signals from an analog domain to a digital domain, the numerical calculation module is used for completing filter parameter selection and running a noise control algorithm, and the DAC module is used for converting the calculation result of the algorithm from the digital domain to a driving signal of an analog domain loudspeaker. All microphones are connected into an ADC module in the controller after passing through an anti-aliasing filter; the turbofan tachometer is connected to a rotational speed acquisition module of the controller; the driving signals of all the loudspeakers are filtered by a low-pass filter and amplified by a power amplifier.
Fig. 3 is a flowchart of an implementation of the method for matching the active noise reduction device of the smoke exhaust ventilator.
As shown in fig. 3, in step S110, the motor of the range hood is first turned off, white noise is generated in the first ANC system by the controller to drive the speaker 20 to vibrate and sound, the first microphone 10 picks up the noise at the outlet air duct opening of the range hood and is collected by the controller, and the controller operates the LMS algorithm to recognize the first transfer function H1 between the second speaker and the first microphone, which is represented by the finite impulse response sequence. The identification process of the transfer function is shown in fig. 4, in which the "system input" corresponds to a white noise signal for driving a speaker, the "desired signal" corresponds to a noise signal collected at the first microphone, the "output signal" is an output of the adaptive filter after one-dimensional convolution with the input signal, and the "unknown system" is the transfer function to be identified. The system identification process is iterated continuously, as the error signal approaches 0, indicating that the system represented using the adaptive filter is approximately equal to the "unknown system". The second transfer function H2 between the second speaker 50 and the third microphone 60, and the third transfer function H3 between the third speaker 70 and the third microphone 60 are all identified by the same method.
As shown in fig. 3, in step S120, the first ANC system is turned off, and the range hood and the second ANC system are turned on. Dividing the lowest rotating speed to the highest rotating speed of the smoke exhaust ventilator into 300 rotating speed grades, starting to fix the rotating speed of the turbine fan from the lowest rotating speed grade, actively reducing noise by using a two-channel FxLMS algorithm during the fixed rotating speed, and recording the rotating speed at the moment and the filter parameters of the corresponding two-channel FxLMS algorithm when the algorithm converges (namely, the noise sound pressure level at the third microphone is basically unchanged after the weakening for a period of time). And repeating the process, regulating the rotating speed from the lowest to the highest, and recording 300 groups of data pairs of < rotating speed and filter parameter > corresponding to 300-level rotating speed.
The block diagram of the two-channel FxLMS algorithm used in step S120 is shown in fig. 5, in whichA second transfer function from the second speaker identified in step S110 to the third microphone, i.e. an estimate of the second transfer function H2; />A third transfer function from the third speaker to the third microphone identified in step S110, i.e. an estimate of a third transfer function H3; x is x f2 (n) is the transfer function of the noise picked up by the second microphone at time n>The output obtained after that; x is x f3 (n) is the transfer function of the noise picked up by the second microphone at time n>The output obtained after that; w (W) 2 And W is equal to 3 Adaptive filters modeled using finite impulse response filters for channels 2 and 3, respectively, W 2 And W is equal to 3 Is adjusted by the LMS; y is 2 (n) and y 3 (n) the signals collected by the second microphone are respectively passed through an adaptive filter W 2 And W is equal to 3 A filtered output; h 2 、P、H 3 Representing the actual transfer function of the second speaker to the third microphone, the transfer function of the second microphone to the third microphone, and the transfer function of the third speaker to the third microphone; y is h2 (n), d (n) and y h3 (n) is n time H respectively 2 、P、H 3 It is noted that in practice only the residual noise, i.e. e (n), can be picked up by the third microphone. Among the above signals (including algorithms), the digital signals processed in the controller are within the dashed box, and the signals outside the dashed box are the signals in the actual physical system.
The two-channel FxLMS algorithm in step S120 includes three parts of input signal filtering, speaker driving signal generation, and filter coefficient updating.
At the discrete time n, the input signal filtering section uses the transfer function identified in step S110And->The signal x (n) collected by the controller through the second microphone is filtered, and the filtering process can be represented by using the following matrix multiplication:
wherein,l denotes the length of the filter.
At a discrete time n instant, the driving signals y of the second and third speakers 2 (n) and y 3 (n) the signal x (n) acquired by the second microphone and the adaptive filter W 2 And W is 3 The linear convolution is written in matrix form as follows:
wherein,l denotes the length of the adaptive filter. Irrespective of the distortion of the loudspeaker, the residual noise signal at time n at the third microphone can be expressed as:
wherein,
at the discrete time n instant, the coefficient W of the adaptive filter 2 And W is equal to 3 The coefficients of (2) are updated by the LMS algorithm according to the residual error signal e (n), and the updating formula is as follows:
wherein,
in step S130, the first ANC system, the second ANC system and the range hood are in a power-on running state, including two steps of anti-noise generation of the first ANC system and anti-noise generation of the second ANC system. The first ANC system anti-noise generation generates anti-noise of the area near the first microphone of the air outlet of the smoke exhaust ventilator, and the second ANC system anti-noise generation generates an anti-noise signal of the area near the third microphone of the smoke exhaust ventilator.
The adaptive notch FxLMS algorithm is used as a control algorithm in the first ANC system to control single frequency noise. As shown in FIG. 6, wherein x is 0 (n) and x 1 (n) is a sine signal and a cosine signal synthesized by using the rotation speed of the turbofan, and the sine signal and the cosine signal are multiplied by the coefficients a (n) and b (n) of the adaptive filter to obtain a loudspeaker driving signal, and the driving signal is multiplied by the noise signal d after passing through the transfer function from the actual first loudspeaker to the first microphone 1 (n) generating noise reduction effect after superposition, residual noise e picked up by the first microphone 1 (n) in turn participating in the updating of coefficients a (n) and b (n) as inputs to the system such that e 1 (n) the converging state is reached at the minimum time. The speaker driving signal generation and filter coefficient update calculation process of the first ANC system may be expressed as follows, respectively
y 1 (n)＝a(n)x 0 (n)+b(n)x 1 (n) type (5)
The input signal of the second ANC system comprises two parts, namely a signal acquired by the second microphone and a turbofan rotating speed signal, and the process does not need the participation of the third microphone. When the second ANC system is running, firstly, the rotation speed of the current turbofan is obtained, secondly, the current rotation speed is compared with the 300-level speed in the step S110, a group of filter parameters corresponding to the closest first-level speed are selected, and finally, the selected filter parameters are used for filtering signals acquired by the second microphone to obtain driving signals of the second loudspeaker and the third loudspeaker (namely, the selected group of filter parameters are respectively replaced in the formula (2)Andand closing the filter parameter update loop of (4). The process is carried out once every 0.3-1 s, and the process is continuously and reciprocally circulated in the system operation.
Claims (10)
1. The multichannel smoke ventilator noise active control device is characterized by comprising a rotating speed sensor arranged on a smoke ventilator turbofan, a first noise pickup microphone arranged at an air outlet at the upper end of the smoke ventilator, a second noise pickup microphone arranged at an air inlet of the smoke ventilator and close to the turbofan, a third noise pickup microphone arranged right below the air inlet of the smoke ventilator, a first speaker component arranged in a inclined tube forming an angle of 45 degrees with an air outlet pipe of the smoke ventilator, a second speaker component and a third speaker component symmetrically arranged at the inner side of the air inlet cover of the smoke ventilator and pointing to the third noise pickup microphone, and a controller arranged on the right side wall of the smoke ventilator; the rotating speed sensor, the first noise pickup microphone, the second noise pickup microphone, the third noise pickup microphone, the first loudspeaker component, the second loudspeaker component and the third loudspeaker component are all connected with the controller through wires.
2. The active control device of claim 1, wherein the first noise pickup microphone comprises a microphone for picking up noise at the outlet of the outlet duct of the range hood.
3. The multi-channel range hood noise active control device of claim 1, wherein said second noise pickup microphone comprises a microphone for picking up range hood generated noise at a range hood intake grill.
4. The active noise control device of claim 1, wherein the third noise pickup microphone comprises a microphone for picking up noise directly under the range hood, and is removable only when the range hood is in service, when the second and third transfer functions are identified and the < rotational speed, the filter parameter > is obtained by pre-training.
5. The active control device of claim 1, wherein the speed sensor comprises a hall speed sensor for measuring the rotational speed of the turbo fan.
6. The active noise control device of the multi-channel range hood according to claim 1, wherein the first speaker unit is installed in a chute connected to the air outlet pipe for generating an anti-noise signal.
7. The active control device of claim 1, wherein the second and third speaker units are configured to generate an anti-noise signal at the air intake.
8. A method for reducing noise of a multi-channel smoke exhaust ventilator noise active control device, characterized in that the multi-channel smoke exhaust ventilator noise active control device according to any one of the preceding claims 1-7 is used; the method comprises the following steps:
keeping other speakers inactive, driving the first speaker to emit white noise by the controller, picking up the white noise emitted by the speaker by the first microphone, and identifying a first transfer function from the first speaker to the first microphone;
keeping other speakers inactive, driving the second speaker to emit white noise by the controller, picking up the white noise emitted by the speaker by the third microphone, and identifying a second transfer function from the second speaker to the third microphone;
keeping other speakers inactive, driving a third speaker to emit white noise by the controller, picking up the white noise emitted by the speaker by a third microphone, and identifying a third transfer function from the third speaker to the third microphone;
keeping the first loudspeaker not working, and normally working the range hood, the first loudspeaker and the second loudspeaker, and adjusting the range hood to be at different rotating speeds to obtain corresponding controller parameters at different rotating speeds;
the range hood, all the loudspeakers and the microphones are operated, and the first ANC system drives the first loudspeaker to generate anti-noise to control noise at an air outlet of the range hood by using a narrow-band adaptive filter active noise reduction algorithm; the second ANC system judges the current rotation speed of the smoke exhaust ventilator once every 0.5-1 second, and selects a group of corresponding filter parameters, so that the controller outputs two groups of anti-noise signals to drive the second loudspeaker and the third loudspeaker to emit anti-noise to control noise in the space around the third microphone.
9. The noise reduction method of the multi-channel smoke exhaust ventilator noise active control device according to claim 8, wherein the system identification algorithm used by the first transfer function, the second transfer function and the third transfer function is a least mean square algorithm LMS, the speaker driving signal is generated by the controller and is used as the input of the transfer function, and the signals collected by the first microphone and the third microphone are used as the output of the transfer function; the corresponding controller parameters at different rotating speeds are a matrix of 2 rows, and each row respectively controls the second loudspeaker and the third loudspeaker; the noise classification method based on the rotating speed equally divides the range hood from the lowest rotating speed to the highest rotating speed into 300 stages, the < rotating speed and filter parameter > pair corresponding to each stage is required to be pre-trained through an FxLMS algorithm before the range hood is formally put into use, and the filter parameter corresponding to the rotating speed stage closest to the current rotating speed is selected as the parameter of a fixed parameter filter when the range hood is formally put into use, so that a loudspeaker driving signal is generated.
10. The noise reduction method of the multi-channel range hood noise active control device of claim 8, further comprising:
the first ANC system is a narrow-band ANC system, and an algorithm used by a controller is an adaptive notch FxLMS algorithm; the algorithm used by the second ANC system is a fixed parameter filter active noise reduction algorithm capable of updating the filter parameters regularly, and the filter parameters are updated according to the operation working condition of the smoke exhaust ventilator.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202311723248.6A CN117628558A (en) | 2023-12-15 | 2023-12-15 | Active control device and noise reduction method for noise of multi-channel smoke exhaust ventilator |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311723248.6A CN117628558A (en) | 2023-12-15 | 2023-12-15 | Active control device and noise reduction method for noise of multi-channel smoke exhaust ventilator |
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| CN117628558A true CN117628558A (en) | 2024-03-01 |
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| CN202311723248.6A Pending CN117628558A (en) | 2023-12-15 | 2023-12-15 | Active control device and noise reduction method for noise of multi-channel smoke exhaust ventilator |
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| CN (1) | CN117628558A (en) |
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