Air conditioner and control method and device thereof, storage medium and computer program product

Abstract

The invention discloses an air conditioner control method and device, an air conditioner, a storage medium and a computer program product. The air conditioner is provided with an indoor unit, a set of reference microphones, a set of error microphones and a set of loudspeakers. The method comprises the steps that under the condition that the air conditioner runs, a set of reference noise signals collected by a set of reference microphones are obtained; obtaining a group of error noise signals collected by a group of error microphones; based on the group of reference noise signals and the group of error noise signals, adopting a multi-channel hybrid active noise control algorithm to obtain a group of output signals; a set of loudspeakers is driven with a set of output signals such that a set of loudspeakers generates secondary noise signals to reduce or even offset error noise signals at a set of error noise signals. According to the scheme, the feedback system is added on the basis of the feedforward system of the ANC control system to set the multi-channel hybrid ANC control system, the noise environment of the air conditioner indoor unit is improved, and the use experience of a user is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of air conditioners, and particularly relates to a control method, device, air conditioner, storage medium and computer program product for an air conditioner, and more particularly to a multi-channel hybrid active noise control method, device, air conditioner, storage medium and computer program product for an air conditioner. Background Art

[0002] With the continuous improvement of people's requirements for the quality of life, an air conditioner not only needs to have efficient refrigeration and / or heating performance, but also needs to provide a quiet and comfortable use experience. In related solutions, air conditioners usually adopt passive noise reduction measures, such as using sound insulation materials for noise reduction, adopting optimized designs for noise reduction, etc. However, these methods can only reduce the noise problem to a certain extent, and the air conditioner noise still affects the user's use experience.

[0003] The above content is only used to assist in understanding the technical solution of the present invention, and does not represent an admission that the above content is prior art. Summary of the Invention

[0004] The purpose of the present invention is to provide a control method, device, air conditioner, storage medium and computer program product for an air conditioner, so as to solve the problem that in related solutions, air conditioners usually adopt passive noise reduction measures, which can only reduce the noise problem to a certain extent, but the air conditioner noise still affects the user's use experience, and achieve the effect of forming a hybrid ANC control system by adding a feedback system on the basis of the feedforward system of the ANC control system, setting a multi-channel hybrid ANC control system, improving the noise environment of the indoor unit of the air conditioner, enhancing the sound quality of the indoor unit of the air conditioner, and enhancing the user's use experience.

[0005] The present invention provides a control method for an air conditioner. The air conditioner has an indoor unit, a set of reference microphones, a set of error microphones and a set of speakers; the set of reference microphones is arranged at the noise source inside the indoor unit, and both the set of reference microphones and the set of speakers are arranged in the noise reduction target area of the indoor unit; when the air conditioner is operating, the set of error microphones can be on the sound transmission path of the set of speakers; the control method of the air conditioner includes: when the air conditioner is operating, acquiring a set of reference noise signals collected by the set of reference microphones; and acquiring a set of error noise signals collected by the set of error microphones; based on the set of reference noise signals and the set of error noise signals, using a multi-channel hybrid active noise control algorithm to obtain a set of output signals; using the set of output signals to drive the set of speakers, so that the set of speakers generates a secondary noise signal to reduce or even cancel the error noise signal at the set of error noise signals.

[0006] In some embodiments, the control system corresponding to the multi-channel hybrid active noise control algorithm includes: a feedforward system and a feedback system; based on the set of reference noise signals and the set of error noise signals, a set of output signals is obtained by using the multi-channel hybrid active noise control algorithm, including: using the feedforward system, based on the set of reference noise signals, to generate a set of feedforward output signals; using the feedback system, based on the set of error noise signals, to generate a set of feedback output signals; and superimposing the set of feedforward output signals and the set of feedback output signals to obtain the set of output signals.

[0007] In some embodiments, wherein using the feedforward system, based on the set of reference noise signals, to generate a set of feedforward output signals includes: using the feedforward system to perform feedforward adaptive filtering on any one of the set of reference noise signals, and then generating a feedforward output signal corresponding to the any one of the reference noise signals; thus, feedforward output signals corresponding to each of the set of reference noise signals are obtained; and the feedforward output signals corresponding to all of the set of reference noise signals are denoted as the set of feedforward output signals.

[0008] And / or, using the feedback system, based on the set of error noise signals, to generate a set of feedback output signals includes: using the feedback system to perform feedback adaptive filtering on any one of the set of error noise signals, and then generating a feedback output signal corresponding to the any one of the error noise signals; thus, feedback output signals corresponding to each of the set of error noise signals are obtained; and the feedback output signals corresponding to all of the set of error noise signals are denoted as the set of feedback output signals.

[0009] In some embodiments, wherein using the feedforward system to perform feedforward adaptive filtering on any one of the set of reference noise signals and then generating a feedforward output signal corresponding to the any one of the reference noise signals includes: in the feedforward system, using the NFxLMS algorithm to perform feedforward adaptive filtering on any one of the set of reference noise signals and then generating a feedforward output signal corresponding to the any one of the reference noise signals.

[0010] And / or, using the feedback system to perform feedback adaptive filtering on any one of the set of error noise signals and then generating a feedback output signal corresponding to the any one of the error noise signals includes: in the feedback system, using the NFxLMS algorithm to perform feedback adaptive filtering on any one of the set of error noise signals and then generating a feedback output signal corresponding to the any one of the error noise signals.

[0011] In some embodiments, the indoor unit has an air outlet, and a wind deflector is provided at the air outlet; the set of error microphones is arranged outside the wind deflector, and the set of speakers is arranged at the bottom of the indoor unit; wherein, the set of error microphones can move along with the wind deflector so that, when the air conditioner is operating, the set of error microphones can be on the sound transmission path of the set of speakers.

[0012] In some embodiments, it further includes: before obtaining a set of output signals by using a multi-channel hybrid active noise control algorithm based on the set of reference noise signals and the set of error noise signals, performing an initialization process to make the set of speakers emit white noise and constructing an acoustic path model of the secondary noise signal of the set of speakers; after obtaining a set of output signals by using a multi-channel hybrid active noise control algorithm based on the set of reference noise signals and the set of error noise signals, using the set of output signals to drive the set of speakers, and based on the acoustic path model, making the set of speakers generate a secondary noise signal to reduce or even cancel the error noise signal at the set of error noise signals.

[0013] Matched with the above method, on the other hand, the present invention provides a control device for an air conditioner. The air conditioner has an indoor unit, a set of reference microphones, a set of error microphones and a set of speakers; the set of reference microphones is arranged at the noise source inside the indoor unit, and both the set of reference microphones and the set of speakers are arranged in the noise reduction target area of the indoor unit; when the air conditioner is operating, the set of error microphones can be on the sound transmission path of the set of speakers; the control device of the air conditioner includes: an acquisition unit configured to, when the air conditioner is operating, acquire a set of reference noise signals collected by the set of reference microphones; and acquire a set of error noise signals collected by the set of error microphones; a control unit configured to obtain a set of output signals by using a multi-channel hybrid active noise control algorithm based on the set of reference noise signals and the set of error noise signals; the control unit is further configured to use the set of output signals to drive the set of speakers to make the set of speakers generate a secondary noise signal to reduce or even cancel the error noise signal at the set of error noise signals.

[0014] In some embodiments, the control system corresponding to the multi-channel hybrid active noise control algorithm includes: a feedforward system and a feedback system; the control unit, based on the set of reference noise signals and the set of error noise signals, uses the multi-channel hybrid active noise control algorithm to obtain a set of output signals, including: using the feedforward system, based on the set of reference noise signals, to generate a set of feedforward output signals; using the feedback system, based on the set of error noise signals, to generate a set of feedback output signals; superimposing the set of feedforward output signals and the set of feedback output signals to obtain the set of output signals.

[0015] In some embodiments, wherein the control unit, using the feedforward system, based on the set of reference noise signals, generates a set of feedforward output signals, including: using the feedforward system, performing feedforward adaptive filtering on any one of the set of reference noise signals, and generating a feedforward output signal corresponding to the any one of the reference noise signals; thus, obtaining feedforward output signals corresponding to each reference noise signal in the set of reference noise signals; denoting the feedforward output signals corresponding to all reference noise signals in the set of reference noise signals as the set of feedforward output signals;

[0016] And / or, the control unit, using the feedback system, based on the set of error noise signals, generates a set of feedback output signals, including: using the feedback system, performing feedback adaptive filtering on any one of the set of error noise signals, and generating a feedback output signal corresponding to the any one of the error noise signals; thus, obtaining feedback output signals corresponding to each error noise signal in the set of error noise signals; denoting the feedback output signals corresponding to all error noise signals in the set of error noise signals as the set of feedback output signals.

[0017] In some embodiments, wherein the control unit, using the feedforward system, performs feedforward adaptive filtering on any one of the set of reference noise signals and generates a feedforward output signal corresponding to the any one of the reference noise signals, including: in the feedforward system, using the NFxLMS algorithm, performing feedforward adaptive filtering on any one of the set of reference noise signals and generating a feedforward output signal corresponding to the any one of the reference noise signals;

[0018] And / or, the control unit, by using the feedback system, after performing feedback adaptive filtering on any one of the set of error noise signals, generates a feedback output signal corresponding to the any one of the error noise signals, including: in the feedback system, by using the NFxLMS algorithm, after performing feedback adaptive filtering on any one of the set of error noise signals, generates a feedback output signal corresponding to the any one of the error noise signals.

[0019] In some embodiments, the indoor unit has an air outlet, and a wind deflector is provided at the air outlet; the set of error microphones is provided outside the wind deflector, and the set of speakers is provided at the bottom of the indoor unit; wherein, the set of error microphones can move along with the wind deflector so that, when the air conditioner is operating, the set of error microphones can be on the sound transmission path of the set of speakers.

[0020] In some embodiments, it further includes: the control unit is further configured to perform an initialization process before obtaining a set of output signals by using a multi-channel hybrid active noise control algorithm based on the set of reference noise signals and the set of error noise signals, so that the set of speakers emits white noise to construct an acoustic path model of the secondary noise signals of the set of speakers; the control unit is further configured to, after obtaining a set of output signals by using a multi-channel hybrid active noise control algorithm based on the set of reference noise signals and the set of error noise signals, drive the set of speakers by using the set of output signals, and based on the acoustic path model, cause the set of speakers to generate secondary noise signals to reduce or even cancel the error noise signals at the set of error noise signals.

[0021] Matched with the above device, on the other hand, the present invention provides an air conditioner, including: the control device of the air conditioner described above.

[0022] Matched with the above method, on the other hand, the present invention provides a storage medium, the storage medium includes a stored program, wherein, when the program runs, it controls the device where the storage medium is located to execute the steps of the control method of the air conditioner described above.

[0023] Matched with the above method, on the other hand, the present invention provides a computer program product, including a computer program, when the computer program is executed by a processor, it implements the steps of the control method of the air conditioner described above.

[0024] Thus, in the solution of the present invention, K reference microphones are arranged inside the indoor unit of the air conditioner, M error microphones are arranged outside the air deflector of the indoor unit of the air conditioner, S speakers are arranged below the indoor unit of the air conditioner, and a feedback system is added on the basis of the feedforward system of the ANC control system to form a multi-channel hybrid ANC control system (i.e., a multi-channel hybrid active noise control system); when performing multi-channel hybrid active noise control, the reference noise signals at the noise source are obtained by the K reference microphones and filtered, and then the feedforward output signals of each speaker are generated, so as to obtain K×S feedforward output signals; at the same time, the error noise signals in the noise reduction target area are obtained by the M error microphones and filtered, and then the feedback output signals of each speaker are generated, so as to obtain M×S feedback output signals; then, the K×S feedforward output signals and the M×S feedback output signals are superimposed to obtain a control signal, so as to use the control signal to drive the S speakers to generate secondary noise signals to cancel the error noise signals at the M error speakers; thus, by adding a feedback system on the basis of the feedforward system of the ANC control system to form a hybrid ANC control system, and setting a multi-channel hybrid ANC control system, the noise environment of the indoor unit of the air conditioner is improved, the sound quality of the indoor unit of the air conditioner is enhanced, and the user experience is improved.

[0025] Other features and advantages of the present invention will be described in the following specification, and some of them will become obvious from the specification or be understood by implementing the present invention.

[0026] The technical solution of the present invention will be further described in detail below through the drawings and embodiments. Description of the Drawings

[0027] Figure 1 It is a schematic flowchart of an embodiment of the control method of the air conditioner of the present invention;

[0028] Figure 2 It is a schematic flowchart of an embodiment of obtaining a set of output signals by using a multi-channel hybrid active noise control algorithm in the method of the present invention;

[0029] Figure 3 It is a schematic flowchart of an embodiment of generating a set of feedforward output signals based on the set of reference noise signals in the method of the present invention;

[0030] Figure 4 It is a schematic flowchart of an embodiment of generating a set of feedback output signals based on the set of error noise signals in the method of the present invention;

[0031] Figure 5 It is a schematic flowchart of an embodiment of constructing an acoustic path model of the secondary noise signal in the method of the present invention;

[0032] Figure 6Schematic structural diagram of an embodiment of the control device of the air conditioner according to the present invention;

[0033] Figure 7 Schematic diagram of the control flow of a multi-channel hybrid active noise control system;

[0034] Figure 8 Block diagram of the control algorithm of a multi-channel hybrid active noise control system;

[0035] Figure 9 Schematic cross-sectional view of the layout of the active noise reduction system;

[0036] Figure 10 Schematic diagram of the overall structure of the active noise reduction system;

[0037] Figure 11 Schematic diagram of the operation steps of the hybrid active noise reduction system.

[0038] Combined with the accompanying drawings, the reference numerals in the embodiments of the present invention are as follows:

[0039] 1 - reference microphone; 2 - error microphone; 3 - speaker; 4 - indoor unit of the air conditioner; 102 - acquisition unit; 104 - control unit. Specific embodiments

[0040] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the specific embodiments and corresponding drawings of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

[0041] Considering that air conditioners in related solutions usually adopt passive noise reduction measures, which can only reduce the noise problem to a certain extent, but the air conditioner noise still affects the user experience. To further improve the noise reduction effect of the air conditioner, active noise control (ANC) technology is introduced into the air conditioner design. ANC is the abbreviation of Active Noise Control, which is mainly used in audio devices such as headphones to reduce or eliminate environmental noise; ANC technology analyzes the sound waves of environmental noise and generates sound waves with opposite phases for superposition and cancellation, thereby achieving the noise reduction effect.

[0042] The noise of the indoor unit of an air conditioner mainly includes the wind noise of the fan system, the refrigerant flow noise, the motor vibration transmission noise, and the high-frequency electromagnetic noise of the controller. The ANC method can effectively eliminate the noise in the low-frequency band. Its basic principle is to obtain the ambient noise through a sound collector and input it into a Digital Signal Processing (DSP) module to generate a secondary noise with the same amplitude and opposite phase as the main noise. The secondary noise is output to the environment through a speaker to reduce the energy of the main noise source. The sound sensor and speaker of the ANC system occupy less space and do not affect the performance of the air conditioner while reducing noise. At the same time, the DSP module can be combined with the control circuit board of the air conditioner, so the ANC system has the advantages of convenient installation, stable working performance, and low cost.

[0043] Some solutions provide an ANC structure, including the layout strategy of a sound collector, a DSP module, a main control module, and a speaker in the indoor unit of an air conditioner. However, its control algorithm adopts a relatively basic feedforward ANC system. The feedforward model requires a reference speaker to be placed at the target sound source to obtain a reference signal in advance. The residual noise signal measured by the error sensor and the reference signal obtained by the sensor are both used as the input of the controller, and the secondary sound source signal is generated and adjusted through the control algorithm. Subsequently, the secondary speaker is driven to emit secondary noise, which undergoes destructive interference with the noise generated by the primary sound source, ultimately minimizing the sound pressure value at the error sensor. This strategy has strong robustness and is applicable not only to narrowband noise signals but also to broadband noise signals. However, due to the use of only the feedforward algorithm, there will be a sound feedback problem, and the anti-environmental interference ability is poor.

[0044] In addition, considering the complex noise environment of the air conditioner, a stable noise control algorithm is required, and multiple speakers and microphones are needed to achieve good noise reduction effects. Therefore, the solution of the present invention proposes a control method for an air conditioner, specifically a multi-channel hybrid active noise control method for an air conditioner. A feedback system is added to the feedforward system of the ANC control system to form a hybrid ANC control system, and the control algorithm of the hybrid ANC control system is further extended to the multi-channel situation to cope with the complex noise environment of the air conditioner, improve the sound quality of the indoor unit of the air conditioner, and enhance the user experience.

[0045] According to an embodiment of the present invention, a control method for an air conditioner is provided, as Figure 1Schematic flowchart of an embodiment of the method of the present invention. The air conditioner has an indoor unit, a set of reference microphones, a set of error microphones, and a set of speakers; the set of reference microphones is arranged at the noise source inside the indoor unit, and both the set of reference microphones and the set of speakers are arranged at the noise reduction target area of the indoor unit. The indoor unit is like the indoor unit 4 of the air conditioner, the set of reference microphones is like K reference microphones, the set of error microphones is like M error microphones, and the set of speakers is like S speakers; when the air conditioner is operating, the set of error microphones can be on the sound transmission path of the set of speakers; in the solution of the present invention, as Figure 1 shown, the control method of the air conditioner includes: step S110 to step S130.

[0046] In step S110, when the air conditioner is operating, obtain a set of reference noise signals collected by the set of reference microphones, specifically obtain a set of reference noise signals collected by the set of reference microphones from the noise source inside the indoor unit; and obtain a set of error noise signals collected by the set of error microphones, specifically obtain a set of error noise signals collected by the set of error microphones from the noise reduction target area of the indoor unit.

[0047] In step S120, based on the set of reference noise signals and the set of error noise signals, use a multi-channel hybrid active noise control algorithm to obtain a set of output signals.

[0048] In step S130, use the set of output signals to drive the set of speakers, so that the set of speakers generates a secondary noise signal to reduce or even cancel the error noise signal at the set of error noise signals.

[0049] Among them, the set of reference microphones includes one or more reference microphones, the set of error microphones includes one or more error microphones, and the set of speakers includes one or more speakers. In the solution of the present invention, the quantity of the hardware is determined according to the test effect of the noise reduction system. However, the control effect of a single channel must be unsatisfactory because the air outlet of the indoor unit of the air conditioner is open, and noise cannot be controlled by only one set of devices.

[0050] The multi-channel hybrid active noise control scheme for an air conditioner proposed by the solution of the present invention designs an active noise reduction control device for the indoor unit of the air conditioner. A feedback system is added to the feedforward system of the ANC control system to form a hybrid ANC control system. The active control system is applied to actual space noise reduction to improve the convergence speed and stability of the active control algorithm, and to improve the response speed and stability of the control algorithm. Further, the control algorithm of the hybrid ANC control system is extended to the multi-channel case to improve the noise reduction effect of the ANC system to cope with the complex noise environment of the air conditioner and further improve the sound quality of the indoor unit of the air conditioner. Among them, sound quality refers to the subjective perception quality of sound by the human ear.

[0051] In some embodiments, the control system corresponding to the multi-channel hybrid active noise control algorithm includes: a feedforward system and a feedback system.

[0052] For the specific process of obtaining a set of output signals by using the multi-channel hybrid active noise control algorithm based on the set of reference noise signals and the set of error noise signals in step S120, refer to the following exemplary description.

[0053] The following combines Figure 2 The schematic flowchart of an embodiment of obtaining a set of output signals by using the multi-channel hybrid active noise control algorithm in the method of the present invention shown in the figure further illustrates the specific process of obtaining a set of output signals by using the multi-channel hybrid active noise control algorithm in step S120, including: step S210 to step S230.

[0054] Step S210, using the feedforward system, based on the set of reference noise signals, generate a set of feedforward output signals.

[0055] Step S220, using the feedback system, based on the set of error noise signals, generate a set of feedback output signals.

[0056] Step S230, superimpose the set of feedforward output signals and the set of feedback output signals to obtain the set of output signals.

[0057] Figure 8 It is a block diagram of the control algorithm for a multi-channel hybrid active noise control system. As Figure 8As shown, the multi-channel hybrid active noise control system (i.e., the feedforward-feedback hybrid subsystem) consists of a feedforward system and a feedback system, specifically including a feedforward subsystem and a feedback subsystem. The control algorithm of the multi-channel hybrid active noise control system proposed by the solution of the present invention is composed of a feedforward output signal generation part and a feedback output signal generation part. The feedforward control signal (i.e., the feedforward output signal) is a control signal generated by the feedforward system according to the reference noise signal (i.e., the reference noise signal) and the error noise signal (i.e., the error noise signal). Similarly, the feedback system will also generate a set of control signals (i.e., the feedback output signal). After the two sets of signals (i.e., the feedforward output signal and the feedback output signal) are superimposed, the control signal of the secondary speaker array is obtained and output to the environment through the speaker to achieve noise control.

[0058] In some embodiments, for the specific process of using the feedforward system in step S210 to generate a set of feedforward output signals based on the set of reference noise signals, refer to the following exemplary description.

[0059] The following combines Figure 3 As shown in the schematic flowchart of an embodiment of generating a set of feedforward output signals based on the set of reference noise signals in the method of the present invention, the specific process of generating a set of feedforward output signals based on the set of reference noise signals in step S210 is further described, including: step S310 to step S320.

[0060] In step S310, using the feedforward system, after performing feedforward adaptive filtering on any one of the set of reference noise signals, a feedforward output signal corresponding to the any one of the reference noise signals is generated; thus, a feedforward output signal corresponding to each reference noise signal in the set of reference noise signals is obtained.

[0061] In step S320, the feedforward output signals corresponding to all the reference noise signals in the set of reference noise signals are denoted as the set of feedforward output signals.

[0062] For the specific process of using the feedback system in step S220 to generate a set of feedback output signals based on the set of error noise signals, refer to the following exemplary description.

[0063] The following combines Figure 4 As shown in the schematic flowchart of an embodiment of generating a set of feedback output signals based on the set of error noise signals in the method of the present invention, the specific process of generating a set of feedback output signals based on the set of error noise signals in step S220 is further described, including: step S410 to step S420.

[0064] Step S410: Using the feedback system, after performing feedback adaptive filtering on any one of the set of error noise signals, a feedback output signal corresponding to the any one of the error noise signals is generated; thus, feedback output signals corresponding to each error noise signal in the set of error noise signals are obtained.

[0065] Step S420: Denote the feedback output signals corresponding to all the error noise signals in the set of error noise signals as the set of feedback output signals.

[0066] Figure 7 It is a schematic diagram of the control process of a multi-channel hybrid active noise control system. Refer to Figure 7 In the example shown, a set of reference microphones, such as K reference microphones, a set of error microphones, such as M error microphones, and a set of speakers, such as S speakers. Figure 7 The structural block diagram of the multi-channel hybrid active control (HANC) algorithm designed by the solution of the present invention can be shown. The multi-channel hybrid active noise control (HANC) algorithm is a technology that combines feedforward and feedback control mechanisms, aiming to improve the effect and adaptability of noise suppression. The entire air conditioner active control algorithm structure includes a feedforward subsystem and a feedback subsystem. The two sub-systems (i.e., the feedforward subsystem and the feedback subsystem) work simultaneously to drive the speaker array to generate a secondary noise signal to cancel the noise at the error speaker. According to formula (3), u_s(n) corresponds to the signal of each speaker, and the subscript s represents the index of the speaker. Assume that the system (i.e., the multi-channel hybrid active noise control system) includes K reference microphones, S speakers, and M error microphones, and K, S, and M are all positive integers; in actual use, the quantities of K, S, and M are flexibly adjusted according to the noise reduction effect. The working process of the multi-channel hybrid active noise control (HANC) algorithm is as follows: K reference microphones acquire the reference noise signal at the noise source. After the reference noise signal is respectively filtered by a feedforward adaptive filter (such as the s-th feedforward filter), a feedforward output signal of each speaker (such as the feedforward output signal of the s-th speaker) is generated. At the same time, M error microphones acquire the error noise signal in the noise reduction target area. After the error noise signal is respectively filtered by a feedback adaptive filter (such as the s-th feedback filter), a feedback output signal of each speaker (such as the feedback output signal of the s-th speaker) is generated. Then, the feedforward output signal and the feedback output signal of each speaker are superimposed to obtain the control signal of the secondary speaker array, such as generating the output signal of the s-th speaker. The secondary speaker array is composed of S speakers.

[0067] In the solution of the present invention, a multi-channel hybrid control system is proposed, that is, a feedback system is added on the basis of the feedforward system of the ANC control system to form a hybrid ANC control system, which actively controls the noise of the indoor unit of the air conditioner, can consider the complex noise sources of the air conditioner, and can resist the noise disturbance in the environment, improving the system stability; thus solving the problem that it is difficult to cope with the complex noise environment of the air conditioner by only using the feedforward or feedback ANC technology.

[0068] In some embodiments, in step S310, after using the feedforward system to perform feedforward adaptive filtering on any one of the group of reference noise signals, a feedforward output signal corresponding to the any one of the reference noise signals is generated, including: in the feedforward system, using the NFxLMS algorithm, after performing feedforward adaptive filtering on any one of the group of reference noise signals, a feedforward output signal corresponding to the any one of the reference noise signals is generated.

[0069] And / or, in step S410, after using the feedback system to perform feedback adaptive filtering on any one of the group of error noise signals, a feedback output signal corresponding to the any one of the error noise signals is generated, including: in the feedback system, using the NFxLMS algorithm, after performing feedback adaptive filtering on any one of the group of error noise signals, a feedback output signal corresponding to the any one of the error noise signals is generated.

[0070] The following combines Figure 8 the example shown to introduce in detail the specific implementation process of the multi-channel hybrid active control (HANC) algorithm.

[0071] In the feedforward-feedback hybrid subsystem, the output of the feedforward controller and the output of the feedback controller are operated to generate S output signals to drive the secondary loudspeaker to emit cancellation sound waves to reduce the noise at the error loudspeaker.

[0072] In the feedforward control system, K reference signal (i.e., reference noise signal) vectors x1(n), x2(n), …, x k (n), corresponding to Figure 2 x(n) in the feedforward system shown, after being filtered by the feedforward filter, the feedforward output signal u fs (n) participating in the driving sound of the s-th secondary loudspeaker is obtained, corresponding to u f (n) in the feedforward system is specifically:

[0073]

[0074] Equation (1) describes the feedforward part of the sound signal emitted by the s-th secondary speaker, rather than the feedforward part of the sound signals emitted by S secondary speakers. That is, by substituting s in Equation (1) with 1, 2, 3, …, S respectively, the feedforward part of the signal emitted by each speaker can be described. In Equation (1), w fjs (n) is the weight coefficient vector of the feedforward filter that participates in the filtering of the j-th reference signal and drives the s-th secondary speaker, w fjs (n) = [w fjs,0 (n), w fjs,1 (n), …, w fjs,(L1-1) (n)] T , corresponding to W f (z) in the feedforward system; L1 is the order of the feedforward control filter; x j (n) is the reference signal vector, and the subscript j indicates that this reference signal is the j-th one among all K reference signals. x j (n) = [x j (n), x j (n - 1, …, xjn - L1 + 1T. n represents the current moment of the noise signal, and the superscript T represents the transpose. ufsn is the noise signal generated by the feedforward system, where the subscript f is the abbreviation of forword in feedforword, and s represents the s-th speaker.

[0075] In the feedback control system, the feedback structure generates M estimated reference signal vectors xb1(n), xb2(n), …, xb M (n). After being filtered by the feedback filter, the resulting feedback output signal u bs (n) that participates in driving the s-th secondary speaker to emit sound corresponds to u b (n) in the feedback system, specifically:

[0076]

[0077] In Equation (2), u bs (n) is the noise signal generated by the feedback system, and the subscript b is the abbreviation of back in feedback.

[0078] w bis (n) is the weight coefficient vector of the feedback filter that participates in the filtering of the i-th estimated reference signal and drives the s-th secondary speaker. w bis (n) = [w bis,0 (n), w bis,1 (n), …, w bis,(L2-1) (n)], corresponding to W b (z) in the feedback system; L2 is the order of the feedback control filter; xb i(n) = [xb i (n), xb i (n - 1,…, xbin - L2 + 1T is the predicted reference signal, corresponding to xbn of the feedback system. The calculation formula can be found in the feedback subsystem section.)

[0079] The outputs of the feed - forward filter and the feedback filter involved in driving the s - th secondary speaker are calculated to obtain the control signal u s (n) output to the s - th secondary speaker, and its expression is:

[0080] u s (n) = u bs (n) + u fs (n) (3).

[0081] The feed - forward subsystem will be specifically described below.)

[0082] As Figure 8 shown, the feed - forward part adopts the multi - channel NFxLMS algorithm. The NFxLMS algorithm, also known as the Filtered - X Normalized Least Mean Square (FXNLMS) algorithm, is an adaptive filtering algorithm mainly used for noise cancellation and signal processing. The NFxLMS algorithm is an improved version of the FXLMS algorithm. By introducing a normalization factor, it adaptively adjusts the step - size parameter, thus better adapting to different signal intensities and noise environments and improving the filtering performance.)

[0083] Since there are S * M secondary paths in the multi - channel control system, the reference signal first passes through the filtering of the secondary path to obtain the filtered reference signal x fksm (n), corresponding to X f (n) in the feed - forward system, and its expression is:

[0084]

[0085] In formula (4), xf k (n) represents the reference signal obtained by the k - th reference microphone, corresponding to X(n) in the feed - forward system; xf k (n) = [x k (n), x k (n - 1),…, x k (n - L3 + 1)] T , where L3 is the length of the secondary path; is the predicted impulse response coefficient of the transfer function of the secondary path between the s - th secondary speaker and the error speaker m, corresponding to It can be obtained through data acquisition experiments. The length L3 of the secondary path is specifically represented by the impulse response function as the mathematical model of the secondary path, indicating the transfer relationship from the secondary speaker to the error microphone.

[0086] The error signal e at the error speaker m of the multi-channel feedforward control system m (n) formula is:

[0087]

[0088] In formula (5), u s is the control signal output to the s-th secondary speaker. See formula (3), u s =[u s (n), u s (n - 1), …, u s (n - L3 + 1)] T , d m (n) is the noise signal at the speaker m, corresponding to d(n) in the figure. The update formula for the feedforward filter weights is:

[0089]

[0090] Formula (6) is the update iteration formula for w fks (n), that is, continuously updating the parameters of w fks (n) over time. x fksm (n) is the filtered reference signal. See formula (4). The noise signal obtained by the k-th reference microphone after passing through the acoustic path between the s-th speaker and the m-th error microphone. In formula (6), the subscript of w fks (n) indicates that this weight coefficient vector participates in the filtering of the k-th reference signal and the driving of the secondary speaker s in the algorithm. μ ks (n) is the normalized step size of the feedforward filter, and its expression is:

[0091]

[0092] Among them, μ fs is the basic step size, ε is a coefficient close to 0 to prevent the denominator from being zero, and ε = 0.0001 can be taken. After introducing the normalized step size, the selection range of the basic step size can be improved.

[0093] The following specifically describes the feedback subsystem.

[0094] The feedback section adopts a feedback algorithm based on internal model control. Compared with traditional feedback algorithms, the estimated reference signal combines the error signal and the interference signal at the error speaker, making the algorithm have better noise reduction effect. The estimated reference signal xb m (n) is expressed as:

[0095]

[0096] The estimated reference signal xb m (n) is filtered through the secondary path to obtain the filtered reference signal xbf msm (n), and its expression is:

[0097]

[0098] where xb m (n) = [xb m (n), xb m (n - 1), …, xb m (n - L3 + 1)] T .

[0099] Since each error speaker is affected by all secondary speakers, all M error signals will participate in the weight update of each adaptive filter in the feedback system. The weight update expression of the feedback filter is:

[0100]

[0101] In formula (10), is the estimated impulse response coefficient of the transfer function of the secondary path between the jth secondary speaker and the mth error speaker.

[0102] Xbf msj (n) = [xbf msj (n), xbf msj (n - 1), …, xbf msj (n - L2 + 1)] T .

[0103] μb ms (n) is the normalized step size of the adaptive filter in the feedback section, and its expression is:

[0104]

[0105] where μ bs is the basic step size, which is used to adjust the adaptation process of the adaptive filter related to the secondary speaker s in the feedback algorithm. ε is a coefficient close to 0 to prevent the denominator from being zero.

[0106] In the solution of the present invention, a multi-channel hybrid control strategy is proposed. Through the collaborative work of multiple microphones and speakers, multiple noise sources are accurately captured and eliminated, thereby improving the noise reduction amount of the ANC system and enhancing the noise reduction effect of the ANC system, thus solving the problem that it is difficult for single-channel control to accurately identify and eliminate all noises in the case of multiple noise sources.

[0107] In some embodiments, the indoor unit has an air outlet, and a wind deflector is provided at the air outlet; the group of error microphones is arranged outside the wind deflector, and the group of speakers is arranged at the bottom of the indoor unit. Among them, the group of error microphones can move along with the wind deflector so that, when the air conditioner is operating, the group of error microphones can be on the sound transmission path of the group of speakers.

[0108] Specifically, K reference microphones are arranged inside the indoor unit, and M error microphones and S speakers are arranged at the air outlet of the indoor unit. Specifically, they are outside the wind deflector at the air outlet of the indoor unit, and the S speakers are arranged at the bottom of the indoor unit. When the wind deflector is opened, the M error microphones can move along with the wind deflector so that the M error microphones appear on the sound transmission path of the S speakers. Among them, the noise source and the noise reduction target area are determined according to the noise reduction requirements. For example, the outlet of the impeller of the indoor unit of the air conditioner (i.e., the position where the reference microphone is arranged) is the noise source, and the air outlet of the air conditioner (i.e., the position where the error microphone is arranged) is the noise reduction target area.

[0109] Figure 9 It is a schematic cross-sectional view of the layout of the active noise control system. As Figure 9 shown, the reference microphone 1 for multi-channel hybrid active noise control is arranged inside the indoor unit 4 of the air conditioner, at position A as shown in Figure 9 , such as the outlet of the impeller of the indoor unit of the air conditioner. The error microphone 2 is arranged outside the wind deflector, at position B as shown in Figure 9 , such as the air outlet of the air conditioner. The speaker 3 is arranged below the indoor unit of the air conditioner. The reference microphone, the error microphone and the speaker form an active noise control system. When the air conditioner is operating and the wind deflector is opened, the error microphone moves downward along with the wind deflector. At the same time, the bracket of the speaker can adjust the direction of the speaker so that the error microphone appears on the sound transmission path of the speaker.

[0110] Figure 10 It is a schematic overall structure view of the active noise control system. Referring to Figure 10 , the multi-channel hybrid active noise control system can increase the number of microphones and speakers to ensure the noise performance of the indoor unit. By adopting the multi-channel hybrid algorithm proposed in the solution of the present invention, the convergence speed and anti-interference characteristics of the noise control system are improved.

[0111] In some embodiments, the control method of the air conditioner according to the solution of the present invention further includes: a process of constructing an acoustic path model of the secondary noise signal.

[0112] The following combines Figure 5 A schematic flowchart of an embodiment of constructing an acoustic path model of the secondary noise signal in the method of the present invention shown below further illustrates the specific process of constructing the acoustic path model of the secondary noise signal, including: step S510 to step S520.

[0113] Step S510, before obtaining a set of output signals by using a multi-channel hybrid active noise control algorithm based on the set of reference noise signals and the set of error noise signals, perform an initialization process to make the set of speakers emit white noise and construct an acoustic path model of the secondary noise signal of the set of speakers.

[0114] Step S520, after obtaining a set of output signals by using a multi-channel hybrid active noise control algorithm based on the set of reference noise signals and the set of error noise signals, use the set of output signals to drive the set of speakers, and based on the acoustic path model, make the set of speakers generate a secondary noise signal to reduce or even cancel the error noise signal at the set of error noise signals.

[0115] Figure 11 It is a schematic flowchart of the operation steps of the hybrid active noise reduction system. As Figure 11 shown, the analysis process of the hybrid active noise control system includes:

[0116] Step S1, system initialization: Make the speakers emit white noise and construct an acoustic path model of all secondary noise signals. The specific process is: Make the speakers send white noise to the error microphones, and the system establishes an acoustic path model between the speakers and the error microphones according to the signals received by the error microphones; for M speakers and S error microphones, there are M*S acoustic paths.

[0117] Step S2, calculate the secondary noise according to the signals of the error microphones and the reference microphones.

[0118] Step S3, release the secondary noise through the speakers to cancel the noise generated by the indoor unit of the air conditioner.

[0119] In the solution of the present invention, the active noise control algorithm adopts a hybrid control algorithm, which has a fast convergence speed, high stability and can adapt to complex noise environments.

[0120] Adopting the technical solution of this embodiment, by setting K reference microphones inside the indoor unit of the air conditioner, M error microphones outside the air deflector of the indoor unit of the air conditioner, and S speakers below the indoor unit of the air conditioner, and adding a feedback system on the basis of the feedforward system of the ANC control system to form a multi-channel hybrid ANC control system (i.e., a multi-channel hybrid active noise control system); when performing multi-channel hybrid active noise control, the K reference microphones obtain the reference noise signals at the noise source and filter them to generate the feedforward output signals of each speaker, thereby obtaining K×S feedforward output signals; at the same time, the M error microphones obtain the error noise signals in the noise reduction target area and filter them to generate the feedback output signals of each speaker, thereby obtaining M×S feedback output signals; then, the K×S feedforward output signals and the M×S feedback output signals are superimposed to obtain a control signal, so as to use the control signal to drive the S speakers to generate secondary noise signals to cancel the error noise signals at the M error speakers; thus, by adding a feedback system on the basis of the feedforward system of the ANC control system to form a hybrid ANC control system and setting a multi-channel hybrid ANC control system, the noise environment of the indoor unit of the air conditioner is improved, the sound quality of the indoor unit of the air conditioner is enhanced, and the user experience is improved.

[0121] According to an embodiment of the present invention, there is also provided a control device for an air conditioner corresponding to the control method of the air conditioner. Refer to Figure 6 The structural schematic diagram of an embodiment of the device of the present invention is shown. The air conditioner has an indoor unit, a set of reference microphones, a set of error microphones, and a set of speakers; the set of reference microphones is arranged at the noise source inside the indoor unit, and the set of reference microphones and the set of speakers are both arranged in the noise reduction target area of the indoor unit. The indoor unit is like the indoor unit 4 of the air conditioner, the set of reference microphones is like K reference microphones, the set of error microphones is like M error microphones, and the set of speakers is like S speakers; when the air conditioner is running, the set of error microphones can be on the sound transmission path of the set of speakers; in the solution of the present invention, as Figure 6 shown, the control device of the air conditioner includes: an acquisition unit 102 and a control unit 104.

[0122] Among them, the acquisition unit 102 is configured to, when the air conditioner is running, acquire a set of reference noise signals collected by the set of reference microphones, specifically, acquire a set of reference noise signals collected by the set of reference microphones from the noise source inside the indoor unit; and acquire a set of error noise signals collected by the set of error microphones, specifically, acquire a set of error noise signals collected by the set of error microphones from the noise reduction target area of the indoor unit. For the specific functions and processing of the acquisition unit 102, refer to step S110.

[0123] The control unit 104 is configured to obtain a set of output signals by using a multi-channel hybrid active noise control algorithm based on the set of reference noise signals and the set of error noise signals. For the specific functions and processing of this control unit 104, refer to step S120.

[0124] The control unit 104 is further configured to drive the set of speakers by using the set of output signals, so that the set of speakers generate secondary noise signals to reduce or even cancel the error noise signals at the set of error noise signals. For the specific functions and processing of this control unit 104, also refer to step S130.

[0125] Among them, a set of reference microphones includes one or more reference microphones, a set of error microphones includes one or more error microphones, and a set of speakers includes one or more speakers. In the solution of the present invention, the quantity of the hardware is determined according to the test effect of the noise reduction system. However, the control effect of a single channel must be unsatisfactory because the air outlet of the indoor unit of the air conditioner is open, and noise cannot be controlled by only one set of devices.

[0126] The multi-channel hybrid active noise control solution for the air conditioner proposed by the solution of the present invention designs an active noise reduction control device for the indoor unit of the air conditioner, adds a feedback system to the feedforward system of the ANC control system to form a hybrid ANC control system, applies the active control system to actual space noise reduction, improves the convergence speed and stability of the active control algorithm, and improves the response speed and stability of the control algorithm; and further extends the control algorithm of the hybrid ANC control system to the multi-channel situation to improve the noise reduction effect of the ANC system to cope with the complex noise environment of the air conditioner and further improve the sound quality of the indoor unit of the air conditioner. Among them, the sound quality refers to the subjective perception quality of sound by the human ear.

[0127] In some embodiments, the control system corresponding to the multi-channel hybrid active noise control algorithm includes: a feedforward system and a feedback system.

[0128] The control unit 104, based on the set of reference noise signals and the set of error noise signals, adopts a multi-channel hybrid active noise control algorithm to obtain a set of output signals, including:

[0129] The control unit 104 is specifically further configured to use the feedforward system to generate a set of feedforward output signals based on the set of reference noise signals. For the specific functions and processing of this control unit 104, also refer to step S210.

[0130] The control unit 104 is specifically further configured to use the feedback system to generate a set of feedback output signals based on the set of error noise signals. For the specific functions and processing of this control unit 104, also refer to step S220.

[0131] The control unit 104 is further specifically configured to superimpose the set of feedforward output signals and the set of feedback output signals to obtain the set of output signals. For the specific functions and processing of this control unit 104, refer to step S230.

[0132] Figure 8 is a block diagram of the control algorithm for a multi-channel hybrid active noise control system. As Figure 8 shown, the multi-channel hybrid active noise control system (i.e., the feedforward-feedback hybrid subsystem) consists of a feedforward system and a feedback system, specifically including a feedforward subsystem and a feedback subsystem. The control algorithm of the multi-channel hybrid active noise control system proposed by the solution of the present invention consists of a feedforward output signal generation part and a feedback output signal generation part. The feedforward control signal (i.e., the feedforward output signal) is a control signal generated by the feedforward system based on the reference noise signal (i.e., the reference noise signal) and the error noise signal (i.e., the error noise signal). Similarly, the feedback system will also generate a set of control signals (i.e., the feedback output signals). After the two sets of signals (i.e., the feedforward output signal and the feedback output signal) are superimposed, the control signal of the secondary loudspeaker array is obtained and output to the environment through the loudspeaker to achieve noise control.

[0133] In some embodiments, the control unit 104 uses the feedforward system to generate a set of feedforward output signals based on the set of reference noise signals, including:

[0134] The control unit 104 is further specifically configured to use the feedforward system to perform feedforward adaptive filtering on any one of the set of reference noise signals, and then generate a feedforward output signal corresponding to the any one of the reference noise signals; thus, a feedforward output signal corresponding to each reference noise signal in the set of reference noise signals is obtained. For the specific functions and processing of this control unit 104, refer to step S310.

[0135] The control unit 104 is further specifically configured to denote the feedforward output signals corresponding to all the reference noise signals in the set of reference noise signals as the set of feedforward output signals. For the specific functions and processing of this control unit 104, refer to step S320.

[0136] And / or, the control unit 104 uses the feedback system to generate a set of feedback output signals based on the set of error noise signals, including:

[0137] The control unit 104 is further specifically configured to use the feedback system to perform feedback adaptive filtering on any one of the set of error noise signals, and then generate a feedback output signal corresponding to the any one of the error noise signals; thus, feedback output signals corresponding to each of the error noise signals in the set of error noise signals are obtained. For the specific functions and processes of the control unit 104, refer to step S410.

[0138] The control unit 104 is further specifically configured to denote the feedback output signals corresponding to all the error noise signals in the set of error noise signals as the set of feedback output signals. For the specific functions and processes of the control unit 104, refer to step S420.

[0139] Figure 7 It is a schematic diagram of the control process of a multi-channel hybrid active noise control system. Refer to Figure 7 In the example shown, a set of reference microphones, such as K reference microphones, a set of error microphones, such as M error microphones, and a set of speakers, such as S speakers. Figure 7 It can display the structural block diagram of the multi-channel hybrid active control (HANC) algorithm designed by the solution of the present invention. The multi-channel hybrid active noise control (HANC) algorithm is a technology that combines feedforward and feedback control mechanisms, aiming to improve the effect and adaptability of noise suppression. The entire active control algorithm structure of the air conditioner includes a feedforward subsystem and a feedback subsystem. The two sub-systems (i.e., the feedforward subsystem and the feedback subsystem) work simultaneously to drive the speaker array to generate a secondary noise signal to cancel the noise at the error speaker. Assume that the system (i.e., the multi-channel hybrid active noise control system) includes K reference microphones, S speakers, and M error microphones, and K, S, and M are all positive integers. The working process of the multi-channel hybrid active noise control (HANC) algorithm is as follows: K reference microphones acquire the reference noise signals at the noise source. The reference noise signals are respectively filtered by feedforward adaptive filters (such as the s-th feedforward filter) to generate the feedforward output signals of each speaker (such as the feedforward output signal of the s-th speaker). At the same time, M error microphones acquire the error noise signals in the noise reduction target area. The error noise signals are respectively filtered by feedback adaptive filters (such as the s-th feedback filter) to generate the feedback output signals of each speaker (such as the feedback output signal of the s-th speaker). Then, the feedforward output signals and the feedback output signals of each speaker are superimposed to obtain the control signal of the secondary speaker array, such as generating the output signal of the s-th speaker.

[0140] In the solution of the present invention, a multi-channel hybrid control system is proposed, that is, a feedback system is added to the feedforward system of the ANC control system to form a hybrid ANC control system, which actively controls the noise of the air conditioner indoor unit, can consider the complex noise sources of the air conditioner, and can resist the noise disturbance in the environment, improving the system stability; thus solving the problem that it is difficult to cope with the complex noise environment of the air conditioner by only using the feedforward or feedback ANC technology.

[0141] In some embodiments, the control unit 104, after performing feedforward adaptive filtering on any one of the group of reference noise signals by using the feedforward system, generates a feedforward output signal corresponding to the any one of the reference noise signals, including: the control unit 104 is specifically further configured to, in the feedforward system, use the NFxLMS algorithm to perform feedforward adaptive filtering on any one of the group of reference noise signals and generate a feedforward output signal corresponding to the any one of the reference noise signals.

[0142] And / or, the control unit 104, after performing feedback adaptive filtering on any one of the group of error noise signals by using the feedback system, generates a feedback output signal corresponding to the any one of the error noise signals, including: the control unit 104 is specifically further configured to, in the feedback system, use the NFxLMS algorithm to perform feedback adaptive filtering on any one of the group of error noise signals and generate a feedback output signal corresponding to the any one of the error noise signals.

[0143] The following combines Figure 8 the example shown to introduce in detail the specific implementation process of the multi-channel hybrid active control (HANC) algorithm.

[0144] In the pre-feedback hybrid subsystem, the output of the feedforward controller and the output of the feedback controller are operated to generate S output signals to drive the secondary loudspeaker to emit cancellation sound waves to reduce the noise at the error loudspeaker.

[0145] In the feedforward control system, K reference signals (i.e., reference noise signals) vectors x1(n), x2(n), …, x k (n) are filtered by the feedforward filter to obtain the feedforward output signal u fs (n) for:

[0146]

[0147] The feedforward part of the sound signal emitted by the s-th secondary speaker is described by formula (1), rather than the feedforward part of the sound signals emitted by the S secondary speakers. That is, by replacing s in formula (1) with 1, 2, 3, …, S respectively, the feedforward part of the signal emitted by each speaker can be described. In formula (1), w fjs (n) is the weight coefficient vector of the feedforward filter that participates in filtering the j-th reference signal and drives the s-th secondary speaker, w fjs (n) = [w fjs,0 (n), w fjs,1 (n), …, w fjs,(L1-1) (n)] T , where L1 is the order of the feedforward control filter; x j (n) is the reference signal vector, and the subscript j indicates that this reference signal is the j-th one among all K reference signals. x j (n) = [x j (n), x j (n - 1), …, x j (n - L1 + 1)] T . n represents the current moment of the noise signal, and the superscript T represents transpose. u fs (n) is the noise signal generated by the feedforward system. The subscript f is the abbreviation of forword in feedforword, and s represents the s-th speaker.

[0148] In the feedback control system, the feedback structure generates M predicted reference signal vectors xb1(n), xb2(n), …, xb M (n). After being filtered by the feedback filter, the feedback output signal u bs (n) that participates in driving the s-th secondary speaker to emit sound is:

[0149]

[0150] In formula (2), u bs (n) is the noise signal generated by the feedback system. The subscript b is the abbreviation of back in feedback.

[0151] w bis (n) is the weight coefficient vector of the feedback filter that participates in filtering the i-th predicted reference signal and drives the s-th secondary speaker. w bis (n) = [w bis,0 (n), w bis,1 (n), …, w bos,(L2-1) (n)], where L2 is the order of the feedback control filter; xb i (n) = [xb i (n), xb i(n - 1), …, xb i (n - L2 + 1)] T is the estimated reference signal, and the calculation formula can be found in the feedback subsystem part.

[0152] The outputs of the feedforward filter and the feedback filter involved in driving the s-th secondary speaker are processed to obtain the control signal u output to the s-th secondary speaker s (n), and its expression is:

[0153] u s (n) = u bs (n) + u fs (n) (3).

[0154] The feedforward subsystem will be specifically described below.

[0155] As Figure 8 shown, the feedforward part adopts the multi-channel NFxLMS algorithm. The NFxLMS algorithm, also known as the Filtered-X Normalized Least Mean Square (FXNLMS) algorithm, is an adaptive filtering algorithm mainly used for noise cancellation and signal processing. The NFxLMS algorithm is an improved version of the FXLMS algorithm. By introducing a normalization factor, it adaptively adjusts the step size parameter, thereby better adapting to different signal strengths and noise environments and improving the filtering performance.

[0156] Since there are S * M secondary paths in the multi-channel control system, the reference signal first needs to be filtered through the secondary paths to obtain the filtered reference signal x fksm (n), and its expression is:

[0157]

[0158] In formula (4), xf k (n) represents the reference signal obtained by the k-th reference microphone, and xf k (n) = [x k (n), x k (n - 1), …, x k (n - L3 + 1)] T , where L3 is the length of the secondary path; is the estimated impulse response coefficient of the transfer function of the secondary path between the s-th secondary speaker and the error speaker m, which can be obtained through data acquisition experiments. The length L3 of the secondary path is specifically represented by the impulse response function as the mathematical model of the secondary path, indicating the transfer relationship from the secondary speaker to the error microphone.

[0159] The error signal e at the error speaker m of the multi-channel feedforward control system m(n) formula is:

[0160]

[0161] In formula (5), u s is the control signal output to the s-th secondary speaker. See formula (3), u s = [u s (n), u s (n - 1), …, u s (n - L3 + 1)] T , d m (n) is the noise signal at speaker m. The update formula for the feedforward filter weights is:

[0162]

[0163] Formula (6) is the update iteration formula for w fks (n), that is, continuously update the parameters of w fks (n) over time. x fksm (n) is the filtered reference signal. See formula (4). The noise signal obtained by the k-th reference microphone after passing through the acoustic path between the s-th speaker and the m-th error microphone. In formula (6), the subscript of w fks (n) indicates that this weight coefficient vector participates in the filtering of the k-th reference signal and the driving of the secondary speaker s in the algorithm. μ ks (n) is the normalized step size of the feedforward filter, and its expression is:

[0164]

[0165] Among them, μ fs is the basic step size, ε is a coefficient close to 0 to prevent the denominator from being zero, and ε = 0.0001 can be taken. After introducing the normalized step size, the selection range of the basic step size can be improved.

[0166] The following specifically describes the feedback subsystem.

[0167] The feedback part adopts a feedback algorithm based on internal model control. Compared with traditional feedback algorithms, the estimated reference signal combines the error signal and the interference signal at the error speaker, making this algorithm have better noise reduction effect. The estimated reference signal xb m (n) expression is:

[0168]

[0169] The estimated reference signal xb m (n) is filtered through the secondary path to obtain the filtered reference signal xbfmsm (n), whose expression is:

[0170]

[0171] where xb m (n) = [xb m (n), xb m (n - 1), …, xb m (n - L3 + 1)] T .

[0172] Since each error speaker is affected by all secondary speakers, all M error signals will participate in the weight update of each adaptive filter in the feedback system. The expression for the weight update of the feedback filter is:

[0173]

[0174] In formula (10), is the estimated impulse response coefficient of the secondary path transfer function between the jth secondary speaker and the mth error speaker.

[0175] Xbf msj (n) = [xbf msj (n), xbf msj (n - 1), …, xbf msj (n - L2 + 1)] T .

[0176] μb ms (n) is the normalized step size of the feedback part of the adaptive filter, and its expression is:

[0177]

[0178] where μ bs is the basic step size, which is used to adjust the adaptation process of the adaptive filter related to the secondary speaker s in the feedback algorithm, and ε is a coefficient close to 0 to prevent the denominator from being zero.

[0179] In the solution of the present invention, a multi-channel hybrid control strategy is proposed. By the collaborative work of multiple microphones and speakers, multiple noise sources are accurately captured and eliminated, thereby improving the noise reduction amount of the ANC system and enhancing the noise reduction effect of the ANC system; thus solving the problem that for the case of multiple noise sources, single-channel control is difficult to accurately identify and eliminate all noises.

[0180] In some embodiments, the indoor unit has an air outlet, and a wind deflector is provided at the air outlet; the set of error microphones is arranged outside the wind deflector, and the set of speakers is arranged at the bottom of the indoor unit. Among them, the set of error microphones can move along with the wind deflector so that, when the air conditioner is operating, the set of error microphones can be on the sound transmission path of the set of speakers.

[0181] Specifically, K reference microphones are arranged inside the indoor unit, M error microphones and S speakers are arranged at the air outlet of the indoor unit. Specifically, they are outside the wind deflector at the air outlet of the indoor unit, and the S speakers are arranged at the bottom of the indoor unit. When the wind deflector is opened, the M error microphones can move along with the wind deflector so that the M error microphones appear on the sound transmission path of the S speakers. Among them, the noise source and the noise reduction target area are determined according to the noise reduction requirements; for example: the outlet of the impeller of the indoor unit of the air conditioner (i.e., the position where the reference microphone is arranged) is the noise source, and the air outlet of the air conditioner (i.e., the position where the error microphone is arranged) is the noise reduction target area.

[0182] Figure 9 It is a schematic cross-sectional view of the layout of the active noise reduction system. As Figure 9 shown, the reference microphone 1 of the multi-channel hybrid active noise control is arranged inside the indoor unit 4 of the air conditioner, at position A as Figure 9 shown, such as the outlet of the impeller of the indoor unit of the air conditioner. The error microphone 2 is arranged outside the wind deflector, at position B as Figure 9 shown, such as the air outlet of the air conditioner. The speaker 3 is arranged below the indoor unit of the air conditioner. The reference microphone, the error microphone and the speaker form an active noise control system. When the air conditioner is operating and the wind deflector is opened, the error microphone moves downward along with the wind deflector. At the same time, the bracket of the speaker can adjust the direction of the speaker so that the error microphone appears on the sound transmission path of the speaker.

[0183] Figure 10 It is a schematic diagram of the overall structure of the active noise reduction system. Refer to Figure 10 above, the multi-channel hybrid active noise control system can increase the number of microphones and speakers to ensure the noise performance of the indoor unit. By adopting the multi-channel hybrid algorithm proposed by the solution of the present invention, the convergence speed and anti-interference characteristics of the noise control system are improved.

[0184] In some embodiments, the control method of the air conditioner according to the solution of the present invention further includes: the process of constructing an acoustic path model of the secondary noise signal, specifically as follows:

[0185] The control unit 104 is further configured to perform an initialization process before obtaining a set of output signals by using a multi-channel hybrid active noise control algorithm based on the set of reference noise signals and the set of error noise signals, so as to cause the set of speakers to emit white noise and construct an acoustic path model of the secondary noise signals of the set of speakers. For the specific functions and processes of the control unit 104, please also refer to step S510.

[0186] The control unit 104 is further configured to, after obtaining a set of output signals by using a multi-channel hybrid active noise control algorithm based on the set of reference noise signals and the set of error noise signals, drive the set of speakers by using the set of output signals, and cause the set of speakers to generate secondary noise signals based on the acoustic path model, so as to reduce or even cancel the error noise signals at the set of error noise signals. For the specific functions and processes of the control unit 104, please also refer to step S520.

[0187] Figure 11 It is a schematic diagram of the operation steps of the hybrid active noise reduction system. As Figure 11 shown, the analysis process of the hybrid active noise control system includes:

[0188] Step S1, system initialization: Cause the speakers to emit white noise and construct an acoustic path model of all secondary noise signals.

[0189] Step S2, calculate the secondary noise according to the signals of the error microphone and the reference microphone.

[0190] Step S3, release the secondary noise through the speakers to cancel the noise generated by the indoor unit of the air conditioner.

[0191] In the solution of the present invention, the active noise control algorithm adopts a hybrid control algorithm, which has a fast convergence speed, high stability, and can adapt to complex noise environments.

[0192] Since the processes and functions implemented by the device in this embodiment basically correspond to the embodiments, principles, and examples of the foregoing method, for the details not described in the description of this embodiment, reference can be made to the relevant descriptions in the foregoing embodiments, and details will not be repeated here.

[0193] According to an embodiment of the present invention, there is also provided an air conditioner corresponding to the control device of the air conditioner. The air conditioner may include: the control device of the air conditioner described above.

[0194] Since the processes and functions implemented by the air conditioner in this embodiment basically correspond to the embodiments, principles, and examples of the foregoing device, for the details not described in the description of this embodiment, reference can be made to the relevant descriptions in the foregoing embodiments, and details will not be repeated here.

[0195] According to an embodiment of the present invention, there is also provided a computer program product corresponding to the control method of an air conditioner, including a computer program which, when executed by a processor, implements the steps of the control method of the air conditioner described above.

[0196] Since the processing and functions implemented by the product of this embodiment are basically corresponding to the embodiments, principles and examples of the foregoing method, for the parts not described in detail in the description of this embodiment, reference may be made to the relevant descriptions in the foregoing embodiments and will not be elaborated herein.

[0197] According to an embodiment of the present invention, there is also provided a storage medium corresponding to the control method of an air conditioner, the storage medium including a stored program, wherein when the program runs, it controls the device where the storage medium is located to execute the steps of the control method of the air conditioner described above.

[0198] Since the processing and functions implemented by the storage medium of this embodiment are basically corresponding to the embodiments, principles and examples of the foregoing method, for the parts not described in detail in the description of this embodiment, reference may be made to the relevant descriptions in the foregoing embodiments and will not be elaborated herein.

[0199] In summary, it is easy for those skilled in the art to understand that, on the premise of no conflict, the above advantageous ways can be freely combined and superimposed.

[0200] The above are only the embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the scope of the claims of the present invention.

Claims

1. A control method for an air conditioner, characterized in that, The air conditioner has an indoor unit, a set of reference microphones, a set of error microphones, and a set of speakers; the set of reference microphones is arranged at the noise source inside the indoor unit, and both the set of reference microphones and the set of speakers are arranged in the noise reduction target area of the indoor unit; When the air conditioner is operating, the set of error microphones can be on the sound transmission path of the set of speakers; The control method of the air conditioner includes: When the air conditioner is operating, obtaining a set of reference noise signals collected by the set of reference microphones; and obtaining a set of error noise signals collected by the set of error microphones; Based on the set of reference noise signals and the set of error noise signals, using a multi-channel hybrid active noise control algorithm to obtain a set of output signals; Using the set of output signals to drive the set of speakers, so that the set of speakers generates secondary noise signals to reduce or even cancel the error noise signals at the set of error noise signals.

2. The control method of the air conditioner according to claim 1, wherein, The control system corresponding to the multi-channel hybrid active noise control algorithm includes: a feedforward system and a feedback system; Based on the set of reference noise signals and the set of error noise signals, using a multi-channel hybrid active noise control algorithm to obtain a set of output signals, including: Using the feedforward system to generate a set of feedforward output signals based on the set of reference noise signals; Using the feedback system to generate a set of feedback output signals based on the set of error noise signals; Superposing the set of feedforward output signals and the set of feedback output signals to obtain the set of output signals.

3. The control method of the air conditioner according to claim 2, characterized in that, Wherein, Using the feedforward system to generate a set of feedforward output signals based on the set of reference noise signals, including: Using the feedforward system to perform feedforward adaptive filtering on any one of the reference noise signals in the set of reference noise signals, and generating a feedforward output signal corresponding to the any one of the reference noise signals; thus, obtaining feedforward output signals corresponding to each reference noise signal in the set of reference noise signals; Denoting the feedforward output signals corresponding to all the reference noise signals in the set of reference noise signals as the set of feedforward output signals; And / or, Using the feedback system to generate a set of feedback output signals based on the set of error noise signals, including: Using the feedback system to perform feedback adaptive filtering on any one of the error noise signals in the set of error noise signals, and generating a feedback output signal corresponding to the any one of the error noise signals; thus, obtaining feedback output signals corresponding to each error noise signal in the set of error noise signals; Denoting the feedback output signals corresponding to all the error noise signals in the set of error noise signals as the set of feedback output signals.

4. The control method of the air conditioner according to claim 3, characterized in that, Wherein, Using the feedforward system to perform feedforward adaptive filtering on any one of the reference noise signals in the set of reference noise signals, and generating a feedforward output signal corresponding to the any one of the reference noise signals, including: In the feedforward system, by using the NFxLMS algorithm, after performing feedforward adaptive filtering on any one of the set of reference noise signals, a feedforward output signal corresponding to the any one of the reference noise signals is generated; and / or, By using the feedback system, after performing feedback adaptive filtering on any one of the set of error noise signals, a feedback output signal corresponding to the any one of the error noise signals is generated, including: In the feedback system, by using the NFxLMS algorithm, after performing feedback adaptive filtering on any one of the set of error noise signals, a feedback output signal corresponding to the any one of the error noise signals is generated.

5. The control method of an air conditioner according to any one of claims 1 to 4, characterized in that, The indoor unit has an air outlet, and a wind deflector is provided at the air outlet; the set of error microphones is provided outside the wind deflector, and the set of speakers is provided at the bottom of the indoor unit; wherein, The set of error microphones can move along with the wind deflector so that when the air conditioner is operating, the set of error microphones can be on the sound transmission path of the set of speakers.

6. The control method of the air conditioner according to any one of claims 1 to 5, characterized in that It further includes: Before obtaining a set of output signals by using a multi-channel hybrid active noise control algorithm based on the set of reference noise signals and the set of error noise signals, an initialization process is performed to make the set of speakers emit white noise and construct an acoustic path model of the secondary noise signal of the set of speakers; After obtaining a set of output signals by using a multi-channel hybrid active noise control algorithm based on the set of reference noise signals and the set of error noise signals, the set of output signals is used to drive the set of speakers, and based on the acoustic path model, the set of speakers generates a secondary noise signal to reduce or even cancel the error noise signal at the set of error noise signals.

7. A control device for an air conditioner, characterized in that, The air conditioner has an indoor unit, a set of reference microphones, a set of error microphones and a set of speakers; the set of reference microphones is provided at the noise source inside the indoor unit, and both the set of reference microphones and the set of speakers are provided in the noise reduction target area of the indoor unit; When the air conditioner is operating, the set of error microphones can be on the sound transmission path of the set of speakers; The control device of the air conditioner includes: An acquisition unit configured to, when the air conditioner is operating, acquire a set of reference noise signals collected by the set of reference microphones; and acquire a set of error noise signals collected by the set of error microphones; A control unit configured to obtain a set of output signals by using a multi-channel hybrid active noise control algorithm based on the set of reference noise signals and the set of error noise signals; The control unit is further configured to use the set of output signals to drive the set of speakers to make the set of speakers generate a secondary noise signal to reduce or even cancel the error noise signal at the set of error noise signals.

8. An air conditioner, characterized in that, It includes: The control device of the air conditioner according to claim 7.

9. A storage medium, characterized in that, The storage medium includes a stored program, wherein when the program runs, it controls the device where the storage medium is located to execute the control method of the air conditioner according to any one of claims 1 to 6.

10. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by a processor, it implements the steps of the control method of the air conditioner according to any one of claims 1 to 6.

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