WO2019080505A1 - 一种主动降噪方法、系统及新能源车 - Google Patents

一种主动降噪方法、系统及新能源车

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Publication number
WO2019080505A1
WO2019080505A1 PCT/CN2018/090099 CN2018090099W WO2019080505A1 WO 2019080505 A1 WO2019080505 A1 WO 2019080505A1 CN 2018090099 W CN2018090099 W CN 2018090099W WO 2019080505 A1 WO2019080505 A1 WO 2019080505A1
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Prior art keywords
signal
frequency
noise
harmony
high frequency
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PCT/CN2018/090099
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English (en)
French (fr)
Inventor
孙亚轩
赵永吉
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比亚迪股份有限公司
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Application filed by 比亚迪股份有限公司 filed Critical 比亚迪股份有限公司
Priority to US16/759,312 priority Critical patent/US11087734B1/en
Priority to EP18871704.5A priority patent/EP3703048B1/en
Publication of WO2019080505A1 publication Critical patent/WO2019080505A1/zh

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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
    • G10K11/1787—General system configurations
    • G10K11/17873—General system configurations using a reference signal without an error signal, e.g. pure feedforward
    • 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
    • G10K11/1752—Masking
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N1/00—Silencing apparatus characterised by method of silencing
    • F01N1/06—Silencing apparatus characterised by method of silencing by using interference effect
    • F01N1/065—Silencing apparatus characterised by method of silencing by using interference effect by using an active noise source, e.g. speakers
    • 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
    • G10K11/1781—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 characterised by the analysis of input or output signals, e.g. frequency range, modes, transfer functions
    • G10K11/17821—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 characterised by the analysis of input or output signals, e.g. frequency range, modes, transfer functions characterised by the analysis of the input signals only
    • G10K11/17823—Reference signals, e.g. ambient acoustic environment
    • 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
    • G10K11/17853—Methods, e.g. algorithms; Devices of the filter
    • G10K11/17854—Methods, e.g. algorithms; Devices of the filter the filter being an adaptive filter
    • 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
    • G10K15/00—Acoustics not otherwise provided for
    • G10K15/02—Synthesis of acoustic waves
    • 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
    • G10K2210/00—Details of active noise control [ANC] covered by G10K11/178 but not provided for in any of its subgroups
    • G10K2210/10—Applications
    • G10K2210/121—Rotating machines, e.g. engines, turbines, motors; Periodic or quasi-periodic signals in general
    • 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
    • G10K2210/00—Details of active noise control [ANC] covered by G10K11/178 but not provided for in any of its subgroups
    • G10K2210/10—Applications
    • G10K2210/128—Vehicles
    • G10K2210/1282—Automobiles
    • 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
    • G10K2210/00—Details of active noise control [ANC] covered by G10K11/178 but not provided for in any of its subgroups
    • G10K2210/30—Means
    • G10K2210/301—Computational
    • G10K2210/3032—Harmonics or sub-harmonics

Definitions

  • the invention relates to the field of high frequency noise reduction, in particular to the field of active noise reduction of high frequency motor noise of new energy vehicles.
  • noise is the sound produced when the sound body makes irregular vibrations.
  • Noise pollution is a public nuisance. It is related to people's subjective will and related to people's living conditions, so it has different characteristics from other public nuisances.
  • the noise generally includes low frequency noise, intermediate frequency noise and high frequency noise.
  • the noise with a frequency of 20 Hz to 200 Hz is low frequency noise
  • the noise with a frequency of 500 Hz to 2 kHz becomes intermediate frequency noise
  • the noise with a frequency of 2 kHz to 16 kHz is high frequency noise.
  • the voices of ordinary people, walking sounds and general singing voices are all low-frequency noise.
  • Low-frequency noise is not harmful to people's physical and mental health under normal circumstances, and in many cases is also conducive to improving work efficiency.
  • High-frequency noise mainly comes from industrial machines (such as loom, lathes, air compressors, pneumatic picks, blowers, etc.), modern vehicles (such as cars, trains, motorcycles, tractors, airplanes, etc.), tweeters, construction sites, and The noise of shopping malls, sports and entertainment venues.
  • industrial machines such as loom, lathes, air compressors, pneumatic picks, blowers, etc.
  • modern vehicles such as cars, trains, motorcycles, tractors, airplanes, etc.
  • tweeters construction sites
  • construction sites and The noise of shopping malls, sports and entertainment venues.
  • the high-frequency noise emitted by the motor of a new energy vehicle is a result of noise synthesis, including mechanical noise, electromagnetic noise and air noise.
  • the frequency is from 1KHz to 12KHz or higher. This high frequency electromagnetic noise will bring people Strong discomfort. Therefore, the management of such noise is very necessary.
  • passive noise reduction also called physical noise reduction.
  • active noise reduction which produces an acoustic signal that is opposite in phase to the noise signal, phase canceling the low frequency motor noise.
  • the traditional sound-absorbing and sound-reducing physical noise reduction technology has now become a general-purpose technology, mainly referring to the use of sound insulation, sound absorption, and sound-absorbing materials to achieve noise reduction.
  • the physical noise reduction is limited by the heat dissipation index of the motor, and can only be used limitedly.
  • the high frequency noise of the motor still does not meet the ideal requirements.
  • the frequency of motor noise is very high and the wavelength is very short, it is difficult to capture its phase to generate inverted sound waves to actively cancel. Even if it can capture, it must constantly adjust the search step, so the number of cycles will be A lot of calculations are very large, and the algorithm is difficult to implement. Even if the algorithm can be implemented, the hardware requirements are high and the cost is high.
  • the applicant has done a lot of research and proposed several solutions, one of which is to construct a harmony signal, which is played in an environment where high-frequency noise reduction processing is required.
  • the acoustic signal in this way, can be fused by the harmonizing signal and the high-frequency noise to perform noise reduction processing, which can greatly improve the sound quality of the acoustic environment to a certain extent.
  • the construction and acoustic signals are relatively simple in the way of performing high-frequency noise reduction processing, and the sound quality of the acoustic environment still has room for further improvement.
  • the present invention provides an active noise reduction method, system and new energy vehicle. .
  • An aspect of the present invention provides an active noise reduction method, including the following steps:
  • the harmony masking signal includes a harmony signal and a masking signal;
  • the harmony signal is a subharmonic of the high frequency noise signal;
  • the active noise reduction method disclosed by the invention is suitable for active noise reduction processing in any high frequency noise environment, and on the one hand constructs a subharmonic signal of the high frequency noise signal as a harmony signal, and also a harmony signal
  • a masking signal similar to the frequency of the high-frequency noise signal is added to mask the high-frequency noise signal, and the subharmonic is added to reduce the ratio of the high-frequency component of the noise in the entire frequency domain, and the high-frequency component is The amount of irritability is reflected in the amount of irritability, so the irritability is reduced.
  • adding a masking signal can make the high-frequency noise signal unclear, and thus, the degree of irritability is also reduced. In this way, the sound quality of the acoustic environment can be further improved.
  • this method is simple and easy to operate, and the cost is small.
  • a second aspect of the invention discloses an active noise reduction system comprising the following modules:
  • a high frequency noise signal frequency acquisition module for obtaining a frequency of a high frequency noise signal in an acoustic environment
  • a harmony masking signal generating module configured to generate a harmony masking signal according to a frequency of the high frequency noise signal;
  • the harmony masking signal includes a harmony signal and a masking signal;
  • the harmony signal is the high frequency Subharmonic of the noise signal;
  • a harmony masking sound playing module configured to input the harmony masking signal into a sound playing device, and cause the harmony masking signal to interact with a high frequency noise signal in an acoustic environment to reduce the acoustic environment Noise processing.
  • the active noise reduction system disclosed by the invention can be applied to active noise reduction processing in any high frequency noise environment, and on the one hand constructs a subharmonic signal of the high frequency noise signal as a harmony signal, and is still in harmony A masking signal similar to the frequency of the high frequency noise signal is added to the signal to mask the high frequency noise signal. Adding subharmonics reduces the ratio of the high frequency components of the noise in the entire frequency domain, and the amount of high frequency components reflects the magnitude of the irritability, so the irritability is reduced. At the same time, adding a masking signal can make the high-frequency noise signal unclear, and thus, the degree of irritability is also reduced. In this way, the sound quality of the acoustic environment can be further improved. At the same time, the system is simple and easy to implement, and the cost is small.
  • a third aspect of the invention provides a new energy vehicle comprising the active noise reduction system described above.
  • the new energy vehicle disclosed by the invention has an active noise reduction system, so that the noise of the high frequency motor of the new energy vehicle can be reduced, and on the one hand, the subharmonic signal of the high frequency noise signal is constructed as The acoustic signal is also added to the harmonic signal based on the mask signal of the high frequency noise signal to mask the high frequency noise signal. Adding subharmonics reduces the ratio of the high frequency components of the noise in the entire frequency domain, and the amount of high frequency components reflects the magnitude of the irritability, so the irritability is reduced.
  • adding a masking signal can make the high-frequency noise signal unclear, and thus, the degree of irritability is also reduced. In this way, the sound quality of the acoustic environment within the new energy vehicle can be further improved.
  • the system is simple and easy to implement, and the cost is small.
  • FIG. 1 is a schematic diagram showing the structure of a harmony signal provided in an embodiment of the present invention.
  • FIG. 2 is a schematic flow chart of an active noise reduction method provided in an embodiment of the present invention.
  • step S1 in FIG. 2 is a schematic diagram of a specific process of step S1 in FIG. 2;
  • step S2 in FIG. 2 is a schematic diagram of a specific process of step S2 in FIG. 2;
  • FIG. 5 is a schematic diagram of a specific process of step S21 in Figure 4;
  • FIG. 6 is a schematic diagram of a specific process of step S212 in FIG. 5;
  • FIG. 7 is a schematic diagram showing the spectrum of a masking signal and a harmony signal provided in a specific embodiment of the present invention.
  • FIG. 8 is a schematic diagram showing another spectrum of a masking signal and a harmony signal provided in an embodiment of the present invention.
  • FIG. 9 is a structural block diagram of an active noise reduction system provided in an embodiment of the present invention.
  • FIG. 10 is a block diagram showing a specific structure of the harmony masking signal generating module of FIG. 9;
  • Figure 11 is a schematic illustration of a particular embodiment of the invention.
  • the high frequency noise signal of the motor is a complex signal including mechanical noise, electromagnetic noise and air noise.
  • the traditional physical noise reduction technology is very mature, it can only handle part of the motor noise signal; the edge noise reduction using active noise control (English full name: ACTIVE NOISE CONTROL, English abbreviation: ANC) technology can only offset part of the low frequency.
  • Noise signals, for high-frequency noise signals there is currently no public report using ANC technology to offset.
  • the method in the present invention is different from the idea of the conventional noise processing method, and our method is to construct harmony sound to form "harmonic noise". That is to say, noise not only exists, but is still heard by us.
  • the invention further perfectes and supplements the related methods and mechanisms of the harmony structure.
  • the sound is noisy and the sound is not good.
  • we have been paying attention to the noise we have been paying attention to the noise, and the sound pressure level is high.
  • We feel noisy so the treatment of the noisy sound is mainly focused on physical noise reduction.
  • the simple attention to the sound is noisy and can not meet the needs of people, so more people began to pay attention to the sound is not good.
  • the upper dotted line in Figure 1 shows the composition of vocal music in musical acoustics.
  • the sound we hear is composed of two parts, the fundamental and harmonics.
  • the frequency of the harmonic (for the sake of distinction, referred to as the harmonic frequency) is an integer multiple of the frequency of the fundamental wave (for the difference period, referred to as the fundamental frequency).
  • the fundamental frequency is XHz
  • the harmonic frequency is AXHz, BXHz, CXHz, DXHz, etc., wherein A, B, C, and D are all positive integers, that is, the harmonic frequency is an integer multiple of the fundamental frequency.
  • the fundamental frequency determines the pitch
  • the harmonic frequency determines the tone
  • the pitch determines that the sound is “not loud”.
  • the tone determines the sound “beautiful or not good” or “good” (of course they are the result of interaction). There is no such simple single correspondence, here is for a better understanding). This can explain the singer's high-pitched sound and the "beep" sound of metal objects across the glass. Although the center frequency is similar, the subjective feelings are different, and the overtones are different.
  • the frequency of motor noise is generally high. If the harmonic components are constructed according to the principle of musical acoustics, the subjective feeling may be improved, but due to the increase of high frequency components, the irritability is also increased. Will increase, can not achieve the purpose of improving the environmental sound quality.
  • the frequency ratio of the harmonic frequency to the fundamental frequency is 2:1; the fundamental frequency is 5000Hz, and the subharmonic component is At 2500 Hz, the fundamental frequency coincides with the subharmonic harmonics twice per vibration, and the frequency ratio of the fundamental frequency to the subharmonic frequency is 2:1; the two are the same.
  • psychoacoustics when we add the subharmonics of the high-frequency signal of the motor, the ratio of the high-frequency components in the whole frequency domain will decrease, and the number of high-frequency components reflects the magnitude of the irritability, so the irritability It is reduced.
  • the same fundamental frequency has many different harmonic components, and the same is true for subharmonics.
  • a harmonic can have many different orders.
  • the fundamental frequency contains the most concordant of the components of the second and fourth harmonics. In the new energy vehicle, we verified through experiments that the harmonic composition including the fourth harmonic improves the sound quality.
  • the so-called sound pressure level is an indicator of the magnitude of the sound pressure.
  • the sound pressure is the change caused by the atmospheric pressure after the sound wave is disturbed, that is, the residual pressure of the atmospheric pressure, which is equivalent to the superposition of a sound wave disturbance on the atmospheric pressure.
  • the pressure changes.
  • the unit is Pascal (Pa).
  • the sound pressure level is expressed by 20 times the common logarithm of the ratio of the sound pressure P of a sound to the basic sound pressure value P0, that is, 20 lgP/P0 in decibels (dB).
  • the A frequency of the standard small print 1 group is 440 Hz
  • the high octave small character 2 group A frequency is 880 Hz
  • the pure octave frequency ratio is 2:1. That is to say, when playing pure octaves, the vibration of the two strings, the high one will vibrate twice, and once it will coincide with the low one. (If we use the subharmonic principle to explain here: the fundamental frequency signal will always coincide with the harmony signal every 2 times of vibration) The coincidence rate is so high, so it sounds harmonious.
  • the basis in physics is that the higher the stability ratio of harmonic energy, the more the Concord (the purely homogeneous interval of music theory includes pure one, pure eight, pure five, pure four).
  • Frequency ratio of other intervals small second degree 16:15, major second degree 9:8, small third degree 6:5, major third degree 5:4, pure fourth degree 4:3, increase four degrees 45:32, minus five degrees 64:45, pure 5 degrees 3:2, small sixth degree 8:5, big sixth degree 5:3, small seventh degree 16:9, big seventh degree 5:27 and so on.
  • the harmonic components of the corresponding pitch changes are respectively generated, and the pitch changes are generally three types: constant, linear decrease, and linear increase. In this way, the octave can generate 9 different harmony components, and the subjective evaluation is performed by the organizer. Finally, the four subharmonics are selected, and the harmony of the pitch linearity is optimal.
  • the first embodiment of the present invention discloses an active noise reduction method, as shown in FIG. 2, which includes the following steps:
  • Step S1 a high frequency noise signal acquisition step: acquiring a frequency of a high frequency noise signal in an acoustic environment;
  • Step S2 and a sound masking signal generating step: constructing a harmony masking signal according to a frequency of the high frequency noise signal;
  • the harmony masking signal includes a harmony signal and a masking signal;
  • Step S3 the sound masking sound playing step: inputting the harmony masking signal into the sound playing device, causing the harmony masking signal to interact with the high frequency noise signal in the acoustic environment to perform the sound environment Noise reduction processing.
  • the frequency of how to acquire the high-frequency noise signal in the acoustic environment in step S1 is not particularly limited in this example, and can be obtained by a method known to those skilled in the art.
  • the so-called acoustic environment refers to a system composed of all sounds in a certain area.
  • the acoustic environment of a new energy vehicle refers to the internal environment of a new energy vehicle.
  • the driver and passenger are located.
  • the space such as in the cab (or in the co-pilot, the effect is equivalent), or the motor compartment is medium.
  • the so-called acoustic ambient noise refers to the noise experienced by the driver or passenger in the acoustic environment, and is specifically collected by the acoustic environment noise collecting device.
  • the acoustic ambient noise includes high frequency noise originating from the motor, which is called motor noise.
  • motor noise high frequency noise originating from the motor
  • the frequency of this howling sound can be divided into two categories, one is frequency. Unchanged, we call it constant frequency howling, and the other type is frequency conversion. We call it frequency conversion howling.
  • Both of the above whistle are high frequency motor noise.
  • it also includes other non-motor noises such as road noise, tire noise, deconstructed vibration noise, etc. These non-motor noise frequencies are relatively low.
  • step S1 can be implemented as follows:
  • Step S11 the noise signal collecting step: collecting acoustic ambient noise in the acoustic environment to obtain a noise signal;
  • Step S12 a high frequency noise signal frequency acquisition step: then extracting a high frequency noise signal from the noise signal to obtain a frequency of the high frequency noise signal.
  • acoustic ambient noise includes high frequency noise originating from a motor, which is called motor noise.
  • motor noise high frequency noise originating from a motor
  • the frequency of the howling sound can be generally divided into two categories, one is frequency. Unchanged, we call it constant frequency howling, and the other type is frequency conversion. We call it frequency conversion howling.
  • Both of the above whistle are high frequency motor noise. On the other hand, it also includes other non-motor noises such as road noise, tire noise, structural vibration and noise, etc. These non-motor noise frequencies are relatively low.
  • the high-frequency noise signal can be extracted in real time, and the frequency of the high-frequency noise signal is analyzed by the spectrum.
  • This method is suitable for all occasions.
  • the versatility is good, but it also has its drawbacks.
  • the acoustic environment is complex and the background signal is strong. The effect of extracting the high-frequency noise signal is not satisfactory.
  • noise sources emitting high frequency noise For some noise sources emitting high frequency noise, collecting relevant operating parameters of the noise source emitting high frequency noise in the acoustic environment, and obtaining a frequency of the corresponding high frequency noise signal according to the operating parameter; The frequency of the high frequency noise signal is corresponding. Analyze the operating parameters corresponding to the high-frequency noise, and establish a one-to-one correspondence between the operating parameters and the frequency of the high-frequency noise signal; obtain the operating parameters of the noise source to obtain the frequency of the high-frequency noise signal. This way the frequency is obtained in a better way.
  • the high frequency noise signal of the new energy vehicle can be obtained by acquiring an operating parameter of the new energy vehicle and acquiring the operating parameter according to the operating parameter.
  • the acquisition of operational parameters may be accomplished by reading data information transmitted by the CAN bus of the new energy vehicle.
  • the operating parameters of the new energy vehicle may also include the speed of the new energy vehicle, the throttle opening, and the like.
  • the relationship between the motor rotational speed and the frequency of its high frequency noise signal can be stored in advance.
  • the CAN bus of the new energy vehicle can be connected, and the operating parameters such as the motor speed, the vehicle speed and the throttle opening can be obtained by reading the data transmitted by the CAN bus of the new energy vehicle.
  • the relationship between the pre-stored motor speed and the frequency of the motor noise signal can be obtained through the CAN bus, and the frequency of the corresponding motor noise signal can be obtained from the motor speed.
  • the operating parameter is taken as an example of the motor speed.
  • the motor speed of the new energy vehicle and the motor noise signal corresponding to the motor speed can be collected; then the frequency domain analysis of the collected motor noise signal can be performed by the spectrum analyzer to obtain the spectral characteristics of the motor noise signal.
  • the step S2 specifically includes the following steps:
  • a harmony signal generating step constructing a harmony signal according to a frequency of the high frequency noise signal
  • a masking signal generating step constructing a masking signal according to a frequency of the high frequency noise signal
  • the generation of the harmony signal with respect to the above-described step S21 is not particularly limited.
  • the first mode is adopted: the preset sound structure database is acquired according to the frequency of the high frequency noise signal to obtain a harmony signal corresponding to the high frequency noise signal;
  • the specific generation of the harmony signal is constructed by the following steps:
  • Step S211 a frequency band determining step of the high frequency noise signal: determining a frequency band to which the high frequency noise signal belongs according to a frequency of the high frequency noise signal;
  • Step S212 the structure of the sound database is called to: call the preset structured sound database according to the frequency band of the high frequency noise signal, to obtain a harmony signal corresponding to the frequency band of the high frequency noise signal;
  • the preset structured sound database stores a plurality of harmony signal samples, each harmonic signal sample corresponding to a noise frequency band, and includes a harmony signal corresponding to the noise frequency band.
  • the preset constructed sound database can be called through the CAN bus, and the data can be obtained therefrom.
  • a harmony signal corresponding to the high frequency signal such as a low frequency harmony signal of 600-1000 Hz.
  • the structure sound database in the above step S212 is specifically constructed as follows:
  • Step S2121 performing frequency band division on the high frequency noise signal to obtain a calibration noise signal of multiple frequency bands;
  • the frequency of the motor noise signal can be divided into high frequency, low frequency, constant frequency, frequency conversion, etc. according to the motor speed. It can be understood that when the motor speed is large, it can be corresponding to high frequency noise; when the motor speed is small, it can be corresponding to low frequency noise; when the motor speed changes little, that is, when it is basically constant, it can be corresponding to constant frequency noise; the motor speed is gradually increased. That is, when there is acceleration and the acceleration is greater than a certain value, it may be corresponding to the variable frequency noise.
  • the frequency division of the motor noise signal is to save the workload when performing frequency construction.
  • high-frequency components in the ambient noise of the vehicle may have a strong sharpness, and a low-frequency component may be appropriately added in the frequency structure to increase a large number of intermediate frequency components.
  • the frequency of the motor noise signal is a high frequency, such as 3000-6000 Hz, and a sound of 600-1000 Hz can be constructed to be added to the high frequency noise.
  • Step S2122 selecting a calibration noise signal of any frequency band, and performing frequency construction on the calibration noise signal of the selected frequency band according to a musical acoustic or psychoacoustic principle to generate a plurality of preselected harmony acoustic signals;
  • the noise signal of the frequency band can be frequency-structured using sound processing software (such as MATLAB) according to musical acoustic or psychoacoustic principles to generate a plurality of preselected harmony signals.
  • sound processing software such as MATLAB
  • Step S2123 Synthesize the calibration noise signal of the selected frequency band with each of the preselected harmony acoustic signals, respectively, to generate and output a plurality of synthesized sound samples, wherein the frequency band of each synthesized sound sample includes the selected frequency band.
  • Frequency band
  • the frequency band of each synthesized sound sample belongs to the selected frequency band.
  • the frequency structure is used to obtain the low-frequency signal in the 400-500 Hz band, and the frequency of the synthesized sound sample obtained by the combination of the two can be 400-6000 Hz, visible, 400-6000 Hz band. Includes the 4000-5000Hz band.
  • the frequency of the noise signal of the selected frequency band can be compensated by the harmony signal, that is, the frequency coverage of the synthesized sound sample is wide.
  • Step S2124 scoring each synthesized sound sample according to a preset evaluation method, and acquiring a harmony corresponding to the calibration noise signal of the selected frequency band from the preselected harmony sound signal according to the score result of each synthesized sound sample. signal.
  • the preset evaluation method may include: 1) determining an evaluator, the evaluator should have normal hearing, and may be a general staff member, the number of people may be required to be more than 10; 2) the scoring standard may be scored by a percentage system, and Use five-level evaluation criteria, such as: excellent: very pleasant (eg, sounds comfortable, calm, pleasant) (80-100 points), good: sweet (60-80 points), medium: generally 40-60 points) Poor: ugly (20-40 points), inferior: difficult to listen to (eg, unpleasant, disturbing, irritating, etc.) (0-20 points), that is, the evaluator can perform a percentage system based on the rating evaluation; 3) Audition conditions, such as audition evaluation in a quieter indoor environment.
  • an evaluation evaluator consisting of 10 male and female adults plays each synthesized sound sample corresponding to the selected frequency band in a relatively quiet indoor environment, and each synthesized sound sample can be played 3 times. After playing 3 times, the scores are scored by 20 evaluators. After the score is completed, the score results are mathematically counted to select the synthesized sound samples with the highest score (eg, the highest average score), and the synthetic sound samples are preselected.
  • the harmony signal acts as a harmony signal corresponding to the noise signal of the selected frequency band.
  • the harmony signal corresponding to the noise signal of each frequency band can be obtained, and the set of all harmony sound signals is the above-mentioned preset construction sound database.
  • the specific generation of the harmony signal is constructed by the following steps:
  • the high frequency noise signal includes a fundamental wave and a harmonic, a fundamental frequency is obtained from a frequency of the high frequency noise signal, and the harmony signal is obtained by a generation function according to a musical acoustic or psychoacoustic principle, the sum
  • the acoustic signal is a subharmonic of a fundamental wave in the high frequency noise signal; wherein a frequency of the harmonic signal is the fundamental frequency
  • n and m are natural numbers and n is less than m.
  • the frequency ratio is 2:1 and the interval is octave, which belongs to the Concord interval.
  • Frequency ratio of other intervals small second degree 16:15, major second degree 9:8, small third degree 6:5, major third degree 5:4, pure fourth degree 4:3, increase four degrees 45:32, minus five degrees 64:45, pure 5 degrees 3:2, small sixth degree 8:5, big sixth degree 5:3, small seventh degree 16:9.
  • the intervals of complete harmony in music theory include pure one, pure eight, pure five, and pure four.
  • the subjective feeling of a fully consonant interval is best. Taking this as an example, when the second degree is small, the frequency of the harmony signal is the fundamental frequency.
  • the frequency of the harmony signal is the fundamental frequency
  • the frequency of the harmony signal is the fundamental frequency
  • the frequency of the harmony signal is the fundamental frequency Pure four degrees
  • the frequency of the harmony signal is the fundamental frequency
  • the frequency of the harmony signal is the fundamental frequency
  • the frequency of the harmony signal is the fundamental frequency
  • the frequency of the harmony signal is the fundamental frequency
  • the frequency of the harmony signal is the fundamental frequency
  • the frequency of the harmony signal is the fundamental frequency
  • the frequency of the harmony signal is the fundamental frequency
  • the fundamental frequency of the harmony signal is the fundamental frequency
  • the fundamental frequency of the harmony signal is the fundamental frequency
  • K represents the slope of the frequency
  • a represents the harmony
  • A represents the harmonic coefficient
  • f represents the frequency of the harmonic signal
  • t represents time.
  • the frequency generation structure signal of the single motor noise signal is easy to form a new enhanced noise signal due to overlap, interference, etc. of other non-motor noise components, resulting in a problem of deterioration of the acoustic environment quality, thereby improving the sound better.
  • Environmental quality when generating the above-described harmony signal, it is also possible to consider the frequency of the noise other than the high-frequency noise signal as the target noise in the acoustic environment, and consider whether the harmony signal overlaps with other noise components, such as overlapping. Then, when constructing the harmony signal, the frequency components of the overlapping portion can no longer be constructed. In this way, it is avoided that the frequency generation structure signal of the single motor noise signal is easy to form a new enhanced noise signal due to overlap, interference, etc. of other non-motor noise components, resulting in a problem of deterioration of the acoustic environment quality, thereby improving the sound better.
  • Environmental quality when generating the above-described harmony signal, it is also possible to consider the frequency of the noise other
  • the effect of the masking signal and its generation mechanism are explained as follows:
  • the masking signal works like this, when a strong sound conceals a weaker sound so that a weaker sound cannot be heard. effect".
  • the auditory system produces a so-called “masking effect”, that is, each pure tone becomes more inaudible or inaudible, or these pure tones are partially or completely “masked”.
  • “Let's use this feature to generate a "masking signal” for high-frequency noise, so that this "masking signal” makes the high-frequency noise signal unclear.
  • the frequency of the "masking signal” is greater than that of the noise signal. A little lower.
  • the frequency is required to be lower than the frequency of the high-frequency noise signal, and in addition, the sound pressure level of the masking signal is consistent with the trend of the sound pressure level of the harmony signal.
  • the so-called change trend is consistent, which means that it matches the trend of the sound pressure level of the harmony signal. For example, if the sound pressure level of the harmony signal is linearly reduced as a whole, the mask signal is also relative to the sound of the high frequency noise signal.
  • the height is reduced, but it should be noted that the magnitude of the decrease does not have to be consistent with the reduction of the harmony signal. If the sound pressure level of the harmony signal is kept constant, the sound pressure level of the mask signal is also consistent with the sound pressure level of the high frequency noise signal.
  • the horizontal axis is the frequency and the vertical axis is the relative sound pressure level; wherein the thick solid line indicates a high frequency noise signal, the thin solid line is a masking signal, and the broken line indicates a harmony signal.
  • the "octave" subharmonic of the harmonic signal high frequency noise signal shown by the broken line the frequency of the subharmonic and the frequency of the high frequency noise signal always satisfy the relationship of 1:2, masking
  • the frequency of the signal is slightly smaller than the high frequency noise signal.
  • the sound pressure level of the subharmonic is generally linearly decreasing. Therefore, the sound pressure level of the masking signal is relatively small relative to the sound pressure level of the high frequency noise signal, thereby masking the noise signal. .
  • the harmony signal indicated by the broken line is an odd-numbered harmonic of the high-frequency noise signal, and the frequency of the sub-harmonic always satisfies an odd relationship with the frequency of the high-frequency noise signal, and masks the signal.
  • the frequency is slightly smaller than the high-frequency noise signal.
  • the subharmonic signal has the same loudness, but is smaller than the noise signal.
  • the sound pressure level of the masked signal is set to be the same as the sound pressure level of the high-frequency noise signal.
  • the masking signal can be obtained as follows:
  • the preset N frequencies are smaller than the frequency of the high frequency noise signal; the sound pressure level of the masking signal is consistent with the change trend of the sound pressure level of the harmony signal.
  • a plurality of sound pressure levels may be set in combination, and subjective evaluation may be performed in combination.
  • the N frequencies and the M preselected sound pressure levels are preset, and the N frequencies and the M preselected sound pressure levels are combined to generate N*M candidate masking signals; and the N*M candidate to be masked
  • the signal is synchronously played with the high-frequency noise signal, subjective evaluation is performed, and the best candidate candidate masking signal is selected as the masking signal; wherein the sound pressure level of the candidate masking signal is smaller than the high-frequency noise a sound pressure level of the signal; the predetermined N frequencies are all smaller than the frequency of the high frequency noise signal.
  • the range of the N frequencies is [f0-a, f0-b]; wherein f0 is the frequency of the high frequency noise signal, and the three satisfy the following expression: f0>a>b; a, b is the empirical value.
  • Step S3 the harmony masking signal is input into the sound playing device for playing to output a noise reduction structure sound, and the sound environment is subjected to noise reduction processing.
  • the sound pair may be played through the sound playing device.
  • the high-frequency motor noise of the new energy vehicle is denoised.
  • the active noise reduction method disclosed by the invention is suitable for active noise reduction processing in any high frequency noise environment, and on the one hand constructs a subharmonic signal of the high frequency noise signal as a harmony signal, and also a harmony signal
  • a masking signal similar to the frequency of the high-frequency noise signal is added to mask the high-frequency noise signal, and the subharmonic is added to reduce the ratio of the high-frequency component of the noise in the entire frequency domain, and the high-frequency component is The amount of irritability is reflected in the amount of irritability, so the irritability is reduced.
  • adding a masking signal can make the high-frequency noise signal unclear and also reduce the degree of irritability. In this way, the sound quality of the acoustic environment can be further improved.
  • this method is simple and easy to operate, and the cost is small.
  • the second embodiment of the present invention discloses an active noise reduction system, as shown in FIG. 9, including the following modules:
  • a high frequency noise signal frequency acquisition module 1 for acquiring a frequency of a high frequency noise signal in an acoustic environment
  • a harmony masking signal generating module 2 configured to generate a harmony masking signal according to a frequency of the high frequency noise signal;
  • the harmony masking signal includes a harmony signal and a masking signal;
  • the harmony signal is the high Subharmonic of the frequency noise signal;
  • a sound masking sound playing module 3 configured to input the harmony masking signal into a sound playing device, and the sound masking signal interacts with a high frequency noise signal in an acoustic environment to perform the sound environment Noise reduction processing.
  • This active noise reduction system is suitable for a variety of acoustic environments that require high frequency noise reduction processing. Especially used in new energy vehicles to reduce the noise of high frequency noise of the motor.
  • the high-frequency noise signal acquisition module generally includes a sound environment noise collecting device, and the sound environment noise collecting device is generally a microphone.
  • the microphone may be a device of the new energy vehicle itself, or may be in the original There are new microphones based on the new energy car with a microphone.
  • the acoustic environment noise collecting device is disposed in a cab or a passenger cab of a new energy vehicle. It mainly collects acoustic environment noise in the space where the cab and passengers are located.
  • the acoustic ambient noise collecting device is generally mounted on a center console in front of the cab and the passenger cab. Alternatively, it can be installed in the motor compartment close to the motor. After the noise signal is acquired, the high frequency noise signal needs to be extracted to obtain the frequency of the high frequency noise signal.
  • the harmony masking signal generating module 2 specifically includes:
  • a harmony signal generation sub-module 21 configured to generate a harmony signal for the frequency of the high-frequency noise signal
  • a masking signal generating sub-module 22 configured to generate a masking signal according to a frequency of the high-frequency noise signal
  • the composite module 23 is configured to combine the harmony signal and the masking signal to obtain the harmony mask signal.
  • the audible masking sound playing module can be any audio-visual device known to those skilled in the art.
  • it in the field of energy vehicles, it can be an additional speaker device, which can be arranged in the driver.
  • the sound playback device can be placed near the motor, that is, the noise source, thereby ensuring that the sound masking signal is played after It is in the same way as the motor noise signal, eliminating the uncertainties such as the attenuation of the acoustic masking signal during the propagation process, improving the noise reduction of the interior environment (ie, the acoustic environment) after the acoustic masking signal is combined with the motor noise signal. effect.
  • it can be a speaker device that comes with the new energy vehicle itself.
  • the sound masking sound playback module is a car audio system in a new energy vehicle.
  • the active noise reduction system disclosed by the invention can be applied to active noise reduction processing in any high frequency noise environment, and on the one hand constructs a subharmonic signal of the high frequency noise signal as a harmony signal, and is still in harmony
  • a masking signal similar to the frequency of the high-frequency noise signal is added to the signal to mask the high-frequency noise signal, and the subharmonic is added to reduce the ratio of the high-frequency component of the noise in the entire frequency domain, and the high-frequency
  • the amount of ingredients reflects the size of the irritability, so the irritability is reduced.
  • adding a masking signal can make the high-frequency noise signal unclear and also reduce the degree of irritability. In this way, the sound quality of the acoustic environment can be further improved.
  • the system is simple and easy to implement, and the cost is small.
  • a third embodiment of the present invention discloses a new energy vehicle 1000 including the active noise reduction system 100 disclosed in the second embodiment described above.
  • the active noise reduction system 100 of the new energy vehicle 1000 is only modified in this example, and does not involve improvements of other structures and systems, and the active noise reduction system 100 and its active noise reduction method have been in the above first embodiment and The description is made in the second embodiment, and is not repeated here.
  • the new energy vehicle 1000 disclosed by the invention has an active noise reduction system 100 thereon, so that the noise of the high frequency motor of the new energy vehicle 1000 can be reduced, and on the one hand, the subharmonics of the high frequency noise signal are constructed.
  • the signal is used as a harmony signal, and a masking signal similar to the frequency of the high-frequency noise signal is added to the harmonic signal to mask the high-frequency noise signal, and the subharmonic is added to make the noise in the entire frequency domain high.
  • the ratio of the frequency component is reduced, and the amount of the high frequency component reflects the magnitude of the irritability, so the irritability is lowered.
  • adding a masking signal can make the high-frequency noise signal unclear and also reduce the degree of irritability. In this way, the sound quality of the acoustic environment within the new energy vehicle can be further improved.
  • the system is simple and easy to implement, and the cost is small.

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Abstract

一种主动降噪方法、系统及新能源车，包括如下步骤：获取声环境中的高频噪声信号的频率；根据所述高频噪声信号的频率，构造生成和声掩蔽信号；所述和声掩蔽信号包括和声信号和掩蔽信号；所述和声信号为所述高频噪声信号的分谐波；将所述和声掩蔽信号输入声音播放装置中播放，以输出降噪构造声音，对所述声环境进行降噪处理。该种主动降噪方法可以进一步提高其声环境的声品质，同时，该种方法简单易操作，成本小。

Description

一种主动降噪方法、系统及新能源车
相关申请的交叉引用
本申请要求比亚迪股份有限公司于2017年10月27日提交的、发明名称为“一种主动降噪方法、系统及新能源车”的、中国专利申请号“201711026134.0”的优先权。
技术领域
本发明涉及高频噪声降噪领域，尤其指对新能源车的高频电机噪声进行主动降噪的领域。
背景技术
从环境保护的角度看，凡是影响人们正常学习，工作和休息的声音凡是人们在某些场合“不需要的声音”，都统称为噪声。如机器的轰鸣声，各种交通工具的马达声、鸣笛声，人的嘈杂声及各种突发的声响等，均称为噪声。从物理角度看，噪声是发声体做无规则振动时发出的声音。噪声污染属于感觉公害，它与人们的主观意愿有关，与人们的生活状态有关，因而它具有与其他公害不同的特点。
噪声一般包括低频噪声、中频噪声和高频噪声，一般频率在20Hz～200Hz的噪声为低频噪声，频率在500Hz～2KHz的噪声成为中频噪声；频率在2kHz～16kHz的噪声为高频噪声。平时人的说话声，走路声和一般的哼歌声都属于低频噪声，低频噪声在一般情况下对人的身心健康没有什么害处，而且在许多情况下还有利于提高工作效率。高频噪声主要来自工业机器(如织布机、车床、空气压缩机、风镐、鼓风机等)、现代交通工具(如汽车、火车、摩托车、拖拉机、飞机等)、高音喇叭、建筑工地以及商场、体育和文娱场所的喧闹声等。这些高强度的噪声危害着人们的机体，使人感到疲劳，产生消极情绪，甚至引起疾病。
以新能源车的电机发出的高频噪声为例，随着新能源产业的迅速发展，也同样给我们带来了电机噪声的问题。尤其是新能源汽车，电机的高频噪声是一种噪声综合的结果，包括机械噪声，电磁噪声以及空气噪声，频率从1KHz到12KHz或者更高，这种高频的电磁噪声会给人带来强烈的不适感。所以对这种噪声的治理是非常有必要的。
现有的消除噪声的技术方案主要有两种，一种是被动降噪，也叫做物理降噪。包括结 构优化，消除共振，阻尼材料进行吸隔声等。另外一种是有源降噪，产生与噪声信号相位相反的声信号，对低频的电机噪声进行相位抵消。
传统的吸隔声物理降噪技术现在已成为通用技术，主要指采用隔音、吸音、消音材料达到降低噪声的效果。但物理降噪受电机散热指标的制约，只能有限采用，对于电机的高频噪声还是达不到理想的要求。另一方面，由于电机噪声的频率很高，波长很短，所以很难去捕捉它的相位来生成反相声波来主动抵消，即使能够捕捉，也要不断去调整搜索步长，这样循环次数会非常多，运算量很大，算法实现起来较为困难，即使算法能够实现，对硬件的要求也会很高，成本高昂。
为对上述高频噪声进行降噪处理，申请人已经做了众多研究，提出了若干解决方案，其中之一便是构造和声信号，在需要进行高频噪声降噪处理的环境中播放该和声信号，如此，就能通过该和声信号与高频噪声进行融合，以进行降噪处理，这在一定程度上能极大的提高声环境的声品质。然而，该种构造和声信号以进行高频降噪处理的方式较单一，其声环境的声品质仍有进一步提升的空间。
发明内容
为解决现有构造和声信号以进行高频降噪处理的方式较单一，其声环境的声品质仍有进一步提升空间的问题，本发明提供了一种主动降噪方法、系统及新能源车。
本发明一方面提供了一种主动降噪方法，包括如下步骤：
获取声环境中的高频噪声信号的频率；
根据所述高频噪声信号的频率，构造生成和声掩蔽信号；所述和声掩蔽信号包括和声信号和掩蔽信号；所述和声信号为所述高频噪声信号的分谐波；
将所述和声掩蔽信号输入声音播放装置中播放，以输出降噪构造声音，对所述声环境进行降噪处理。
本发明公开的该种主动降噪方法，适用于任何高频噪声环境中进行主动降噪处理，其一方面构造其高频噪声信号的分谐波信号作为和声信号，同时还在和声信号的基础上加入一与高频噪声信号的频率相近的掩蔽信号用来掩蔽高频噪声信号，加入分谐波可使整个频域之中噪声的高频成分所占有的比值降低，而高频成分的多少反映了烦躁度的大小，所以烦躁度是降低的。同时，加入掩蔽信号可使高频噪声信号变得不清晰，如此，也会使得烦躁度的程度降低。如此，可以进一步提高其声环境的声品质。同时，该种方法简单易操作，成本小。
本发明第二方面公开了一种主动降噪系统，包括如下模块：
高频噪声信号频率获取模块，用于获取声环境中的高频噪声信号的频率；
和声掩蔽信号生成模块，用于根据所述高频噪声信号的频率，构造生成和声掩蔽信号；所述和声掩蔽信号包括和声信号和掩蔽信号；所述和声信号为所述高频噪声信号的分谐波；
和声掩蔽声音播放模块，用于将所述和声掩蔽信号输入声音播放装置中播放，使所述和声掩蔽信号与声环境中的高频噪声信号相作用，以对所述声环境进行降噪处理。
本发明公开的该种主动降噪系统，可应用于任何高频噪声环境中进行主动降噪处理，其一方面构造其高频噪声信号的分谐波信号作为和声信号，同时还在和声信号的基础上加入与高频噪声信号的频率相近的掩蔽信号用来掩蔽高频噪声信号。加入分谐波可使整个频域之中噪声的高频成分所占有的比值降低，而高频成分的多少反映了烦躁度的大小，所以烦躁度是降低的。同时，加入掩蔽信号可使高频噪声信号变得不清晰，如此，也会使得烦躁度的程度降低。如此，可以进一步提高其声环境的声品质。同时，该种系统简单易实现，成本小。
本发明第三方面提供了一种新能源车，其包括上述主动降噪系统。本发明公开的新能源车，由于其上设有主动降噪系统，因此可对新能源车的高频电机噪声进行降噪处理，其一方面构造其高频噪声信号的分谐波信号作为和声信号，同时还在和声信号的基础上加入与高频噪声信号的频率相近的掩蔽信号用来掩蔽高频噪声信号。加入分谐波可使整个频域之中噪声的高频成分所占有的比值降低，而高频成分的多少反映了烦躁度的大小，所以烦躁度是降低的。同时，加入掩蔽信号可使高频噪声信号变得不清晰，如此，也会使得烦躁度的程度降低。如此，可以进一步提高新能源车内的声环境的声品质。同时，该种系统简单易实现，成本小。
附图说明
图1是本发明具体实施方式中提供的和声信号构成示意图；
图2是本发明具体实施方式中提供的主动降噪方法流程示意图；
图3是图2中步骤S1具体流程示意图；
图4是图2中步骤S2具体流程示意图；
图5是图4中步骤S21具体流程示意图；
图6是图5中步骤S212具体流程示意图；
图7是本发明具体实施方式中提供的一种构造掩蔽信号和和声信号的频谱示意图；
图8是本发明具体实施方式中提供的另一种构造掩蔽信号和和声信号的频谱示意图；
图9是本发明具体实施方式中提供的主动降噪系统结构框图；
图10是图9中和声掩蔽信号生成模块的具体结构框图；
图11是本发明具体实施方式中提供的示意图。
其中，1、高频噪声信号频率获取模块；2、和声掩蔽信号生成模块；3、和声掩蔽声音播放模块；21、和声信号生成子模块；22、掩蔽信号生成子模块；23、复合子模块；100、主动降噪系统；1000、新能源车。
具体实施方式
为了使本发明所解决的技术问题、技术方案及有益效果更加清楚明白，以下结合附图及实施例，对本发明进行进一步详细说明。应当理解，此处所描述的具体实施例仅仅用以解释本发明，并不用于限定本发明。
申请人在研究过程中发现，在高频噪声的降噪处理是一个复杂的过程。以电机噪声为例，电机的高频噪声信号是一个复杂的信号，包括机械噪声，电磁噪声以及空气噪声。传统的物理降噪技术虽然已经很成熟，但依然只能处理部分的电机噪声信号；有缘降噪利用主动噪声控制(英文全称：ACTIVE NOISE CONTROL，英文简称：ANC)技术也只能抵消部分的低频噪声信号，对于高频噪声信号，目前还没有利用ANC技术进行抵消的公开报道。本发明中的方法不同于以往噪声处理方法的思路，我们的方法是构造和声，形成“和声噪音”。也就是说噪声不仅存在，而且仍然被我们听见。本发明对这种和声构造的相关方法和机理做了进一步的完善和补充。
对于声音的感知我们通常有两方面的认识，声音吵不吵和声音好不好听。以往传统的噪声处理上面我们都是在关注声音吵不吵，声压级高了，我们就觉得吵，所以对声音吵不吵方面的处理主要集中在物理降噪手段。随着人们生活品质的提高，单纯的关注声音吵不吵已经满足不了人们的需求，所以更多人的开始关注声音好不好听。
如图1所示，图1中上部的虚线框显示了在音乐声学中声乐的组成原理，在音乐声学中，我们听见的声音(同样包括噪音)是由两部分组成的，基波和谐波(泛音)，通常谐波的频率(为区别起见，简称谐波频率)是基波的频率(为区别期间，简称基频)成分的整数倍，比如假设基频为XHz，则谐波频率为AXHz、BXHz、CXHz、DXHz等，其中A、B、C、D都为正整数，也就是说谐波频率是基频频率整数倍。基频决定着音高，谐波频率决定音色，音高是决定这个声音“响不响”，音色来决定声音“美不美”或“好不好听”(当然它们之间都是相互作用的结果，没有这么简单的单一对应，此处是为了更好的理解)。这样 就可以解释歌唱家的高音和金属物体划过玻璃时的“吱吱”声虽然中心频率相近，但主观感受却天壤之别的原因，两者的泛音不同。
在新能源车中，电机噪声的频率一般都会很高，如果完全按照音乐声学的原理来构造它的谐波成分的话，可能主观感受会有所提高，但由于高频成分的增加，烦躁度也会增加，不能达到提高环境声品质的目的。
于是我们反向思考，如图1中下部虚线框所示，加入高频信号的分数谐波(简称分谐波)成分作为和声信号，比如，假设高频噪声信号的基频为XHz，则构造生成的分谐波作为和声信号时，其频率为X/AHz、X/BHz、X/CHz、X/DHz等。构造机理依然是音乐声学的相关原理。不同的是整数倍变成了整分数之一倍，长度变化表示分谐波声压级的不同，对应于信号幅度的不同。(在大量的实验基础上，我们发现当和声信号的幅度依次线性减小时，和声的主观感受是最好的)。在主观感受中加入分谐波和加入谐波的效果是一样的，都能提高声品质，他们在物理机制中的解释也是一样的，也就是两个信号重合的几率是一样的，比如，基频为5000Hz，谐波频率是10000Hz，谐波每振动两次就有一次是跟基频重合的，谐波频率与基频的频率比为2:1；基频为5000Hz，分谐波成分是2500Hz，基频每振动两次就有一次跟分谐波重合，基频与分谐波频率的频率比是2:1；两者是一样的。在心理声学中，当我们加入电机高频信号的分谐波时，在整个频域之中高频成分所占有的比值就会降低，而高频成分的多少反映了烦躁度的大小，所以烦躁度是降低的。同一基频有很多不同的谐波组成，分谐波也是如此，而一个谐波又可以有很多不同阶次的组成，在音乐声学中，基频包含二次和四次谐波的成分最协和，在新能源车中，通过实验我们验证了包含四次谐波的和声组成对提高声品质改善最大。
所谓声压级(sound pressure level)是表征声压大小的指标，声压是大气压受到声波扰动后产生的变化，即为大气压强的余压，它相当于在大气压强上的叠加一个声波扰动引起的压强变化。声波通过媒质时，由于振动所产生的压强改变量。它是随时间变化的，实测声压是它的有效值。单位是帕斯卡(Pa)。声压级用某声音的声压P与基本声压值P0之比的常用对数的20倍来表示，即20lgP/P0，单位为分贝(dB)。
在音乐声学中，标准音小字1组的A频率是440Hz，高八度的小字2组A频率是880Hz，可以看出纯八度的频率比是2:1。也就是说，在弹奏纯八度时，两个音弦的震动，高的那个音每震动2次，就会有一次是跟低的那个音是重合的。(此处若用分谐波原理来解释：基频信号每振动2次总会有一次与和声信号重合)重合率如此之高，所以听起来和谐。在物理学中的依据是，谐波能量中稳合比例越高，则越协和(乐理中完全协和的音程包括纯一、纯八、纯五、纯四)。其他音程的频率比：小二度16:15，大二度9:8，小三度6:5，大三度 5:4，纯四度4:3，增四度45:32，减五度64:45，纯五度3:2，小六度8:5，大六度5:3，小七度16:9，大七度5:27等。
了解以上的心理声学和音乐声学的相关知识，我们就可以进行分谐波构造和声信号了，而且可以保证科学性和正确性。在进行一个分谐波构造时首先确定引起不适的频率组成(在电机工作状态下，车内一般为高频信号)，对应音乐声学谐波组成来对分谐波进行音程构造。我们经过大量的实验得到符合我们的规律，生成四次分谐波、三次分谐波和两次分谐波(举例说明：基频信号为1000Hz，则生成八度的四次分谐波为500Hz、250Hz、125Hz、62.5Hz；三次谐波为500Hz、250Hz、125Hz；两次谐波为500Hz、250Hz)。然后分别生成对应的音高变化的谐波成分，音高变化一般是三种：不变，线性减小，线性增大。这样八度这一种音程就可以生成9中不同的和声组成，进过组织人员进行主观评价，最终选出四次分谐波，音高线性减小的和声组合最优。
同时，在后期的试验和研究中我们发现，在进行上述和声构造的同时，我们给目标声音加入一个与之频率相近的声音信号，为区别起见，称其为掩蔽信号，加入该掩蔽信号后，主观感受改善的程度更加的大。
经上述原理解释，申请人经过大量实验验证，提出了新的对高频噪声信号进行降噪的方法、系统；并将其应用在新能源车上。下面将通过实施例一一解释说明。
本发明第一实施例公开了一种主动降噪方法，如下图2所示，其包括如下步骤：
步骤S1、高频噪声信号获取步骤：获取声环境中的高频噪声信号的频率；
步骤S2、和声掩蔽信号生成步骤：根据所述高频噪声信号的频率，构造生成和声掩蔽信号；所述和声掩蔽信号包括和声信号和掩蔽信号；
步骤S3、和声掩蔽声音播放步骤：将所述和声掩蔽信号输入声音播放装置中播放，使所述和声掩蔽信号与声环境中的高频噪声信号相作用，以对所述声环境进行降噪处理。
下面对各步骤S1-S3进行一一解释说明。
关于步骤S1如何获取声环境中的高频噪声信号的频率，本例中并不特别限定，可以采用本领域技术人员所公知的方法获得。
其中，所谓声环境指在一定的区域中，所有声音组成的系统，以新能源车为例，新能源车的声环境指新能源车内部环境，具体的，本例中指驾驶员和乘客所处的空间中，比如驾驶室内(或者置于副驾驶室内，效果也是等效的)、或者电机仓中等。
所谓的声环境噪声，指在声环境中为驾驶员或乘客感受到的噪声，具体通过声环境噪声采集装置进行采集。一方面，该声环境噪声包括来源于电机的高频噪声，将其称为电机噪声。通过对新能源车的高频电机噪声的研究，我们发现，当电机转速达到一定的值时， 会产生啸叫声，这种啸叫声的频率总体上可以分为两类，一类是频率不变的，我们称之为恒频啸叫，另一类是变频的，我们称之为变频啸叫。上述两种啸叫均是高频的电机噪声。另一方面，还包括其他非电机噪声，比如路噪、胎噪、解构振动噪声等，这些非电机噪声的频率相对较低。
本例中，比如，如图3所示，步骤S1可以通过如下方式实现：
步骤S11、噪声信号采集步骤：采集声环境中的声环境噪声，获得噪声信号；
步骤S12、高频噪声信号频率获取步骤：然后从所述噪声信号中提取高频噪声信号，获得所述高频噪声信号的频率。
以新能源车为例，声环境噪声包括来源于电机的高频噪声，将其称为电机噪声。通过对新能源车的高频电机噪声的研究，我们发现，当电机转速达到一定的值时，会产生啸叫声，这种啸叫声的频率总体上可以分为两类，一类是频率不变的，我们称之为恒频啸叫，另一类是变频的，我们称之为变频啸叫。上述两种啸叫均是高频的电机噪声。另一方面，还包括其他非电机噪声，比如路噪、胎噪、结构振动噪声等，这些非电机噪声的频率相对较低。
通过该种方式，可以实时提取高频噪声信号，并通过频谱分析出其高频噪声信号的频率。该种方式适用于所有场合。通用性好，但也有其弊端，比如声环境情况复杂，背景信号较强，提取该高频噪声信号时效果不理想。
对于某些发出高频噪声的噪声源，采集声环境中发出高频噪声的噪声源的相关运行参数，并根据所述运行参数获得对应的高频噪声信号的频率；所述运行参数与所述高频噪声信号的频率呈对应关系。分析与高频噪声相对应的运行参数，可预先建立运行参数与高频噪声信号的频率之间的一一对应关系；获得噪声源的运行参数即获得高频噪声信号的频率。该种方式获得频率的方式更佳。
比如，以所述噪声源为新能源车为例，则上述新能源车的高频噪声信号可通过如下步骤获得：采集新能源车的运行参数，并根据所述运行参数获取与运行参数相关联的高频噪声信号的频率；所述运行参数至少包括所述新能源车的电机转速，所述电机转速与所述高频噪声信号的频率呈对应关系。
在本发明的实施例中，可以通过读取新能源车的CAN总线传输的数据信息以实现对运行参数的采集。可选地，新能源车的运行参数还可以包括新能源车的车速、油门开度等。
具体地，可以预先存储电机转速与其高频噪声信号(此处即电机噪声信号)的频率之间的关系。在采集运行参数时，可以接入新能源车的CAN总线，通过读取新能源车的CAN总线传输的数据，即可得到电机转速、车速、油门开度等运行参数。进而可以通过CAN总 线获取预先存储的电机转速与电机噪声信号的频率之间的关系，根据电机转速从中获取对应的电机噪声信号的频率。
具体地，以运行参数为电机转速为例进行说明。在不同的工况下，可以采集新能源车的电机转速和该电机转速对应的电机噪声信号；然后可以通过频谱分析仪对采集的电机噪声信号进行频域分析，以获得电机噪声信号的频谱特征信息，如频率和声压级；进而可得到电机转速与电机噪声信号的频率和声压级之间的对应关系。
如图4所示，本例中，所述步骤S2具体包括如下步骤：
S21、和声信号生成步骤：根据所述高频噪声信号的频率，构造生成和声信号；
S22、掩蔽信号生成步骤：根据所述高频噪声信号的频率，构造生成掩蔽信号；
S23、复合步骤：将所述和声信号和掩蔽信号复合获得所述和声掩蔽信号。
关于上述步骤S21构造生成和声信号，并不特别限定。
比如采用方式一：根据所述高频噪声信号的频率通过调用预设的构造声音数据库以获取与所述高频噪声信号对应的和声信号；
或者采用方式二：根据所述高频噪声信号的频率通过发生函数获得所述电机噪声信号相对应的和声信号。
下边对上述方式一和方式二分别进行解释说明。
如下图5所示，在方式一中，其具体通过如下步骤构造生成和声信号：
步骤S211、高频噪声信号的频段判断步骤：根据所述高频噪声信号的频率判断所述高频噪声信号的所属频段；
步骤S212、构造声音数据库调用步骤：根据所述高频噪声信号的所属频段调用所述预设的构造声音数据库，以获取与所述高频噪声信号的所属频段相对应的和声信号；其中，所述预设的构造声音数据库中存储有多个和声信号样本，每个和声信号样本对应一个噪声频段，且包括与该噪声频段相对应的和声信号。
具体地，在一个示例中，如果通过电机转速获取到的电机噪声信号的频率取值为4000-5000Hz，即为高频噪声信号，则可以通过CAN总线调用预设的构造声音数据库，从中可以获取与该高频信号相对应的和声信号，如600-1000Hz的低频的和声信号。
如图6所示，上述步骤S212中的构造声音数据库，具体通过如下方式构建：
步骤S2121：对所述高频噪声信号进行频段划分以获得多个频段的标定噪声信号；
可以根据电机转速将电机噪声信号的频率分为高频、低频、恒频、变频等。可以理解，电机转速较大时，可以是对应高频噪声；电机转速较小时，可以是对应低频噪声；电机转速变化较小，即基本恒定时，可以是对应恒频噪声；电机转速逐渐增加，即有加速度、且 加速度大于一定值时，可以是对应变频噪声。
其中，对电机噪声信号进行频段划分是为了在进行频率构造时节省工作量。例如，车内环境噪声中的高频成分会有比较强烈的尖锐感，在进行频率构造时可以适当添加低频成分，以增加较多中间频率成分。
举例而言，电机噪声信号的频率为高频，如3000-6000Hz时，可以构造600-1000Hz的声音以增加至该高频噪声中。
步骤S2122：选择任一频段的标定噪声信号，并根据音乐声学或心理声学原理对所选频段的标定噪声信号进行频率构造以生成多个预选和声信号；
具体地，对于任一频段的标定噪声信号，可以根据音乐声学或心理声学原理利用声音处理软件(如MATLAB)对该频段的噪声信号进行频率构造以生成多个预选和声信号。
步骤S2123：将所选频段的标定噪声信号分别与每个预选和声信号进行合成，以生成多个合成声音样本并输出，其中，每个合成声音样本的频率的所属频段均包括所述所选频段；
其中，每个合成声音样本的频率的所属频段均包括所选频段。例如，对于4000-5000Hz频段的噪声信号，进行频率构造后得到400-500Hz频段的低频信号，两者合成后得到的合成声音样本的频率的所属频段可以为400-6000Hz，可见，400-6000Hz频段包括4000-5000Hz频段。由此，通过和声信号可以对所选频段的噪声信号的频率进行补偿，即使得合成声音样本的频率覆盖范围广。
步骤S2124：根据预设评价方法对每个合成声音样本进行评分，并根据每个合成声音样本的评分结果从所述预选和声信号中获取一个作为所选频段的标定噪声信号相对应的和声信号。
其中，预设评价方法可以包括：1)确定评价人员，评价人员应具有正常的听觉，可以是一般的工作人员，人数可以要求在10人以上；2)评分标准，可以采用百分制进行评分，同时采用五级评价标准，如，优：很悦耳(如，听起来令人舒服、平静、愉悦)(80-100分)，良：悦耳(60-80分)，中：一般40-60分)，差：难听(20-40分)，劣：很难听(如，听起来令人不舒服、令人不安、烦躁等)(0-20分)，即评价人员可以基于分级评价进行百分制评分；3)试听条件，如可以在较为安静的室内环境中进行试听评价。
举例而言，由男女成年人各10人组成评价人员，在较为安静的室内环境中，播放所选频段对应的每个合成声音样本，每个合成声音样本可以播放3遍。在播放3遍后，由20个评价人员进行评分，评分完成后，对评分结果进行数理统计，以选出评分最高(如，平均分最高)的合成声音样本，将该合成声音样本对应的预选和声信号作为与所选频段的噪声 信号相对应的和声信号。同理，可以获取每个频段的噪声信号对应的和声信号，所有和声信号的集合即为上述预设的构造声音数据库。
在方式二中，其具体通过如下步骤构造生成和声信号：
所述高频噪声信号包括基波和谐波，从所述高频噪声信号的频率中获得基波频率，并根据音乐声学或心理声学原理，通过发生函数获得所述和声信号，所述和声信号为所述高频噪声信号中基波的分谐波；其中，所述和声信号的频率为所述基频的
Figure PCTCN2018090099-appb-000001
其中，n、m为自然数，n小于m。比如，在音乐声学中频率比是2:1的音程为八度，属于协和音程。其他音程的频率比：小二度16:15，大二度9:8，小三度6:5，大三度5:4，纯四度4:3，增四度45:32，减五度64:45，纯五度3:2，小六度8:5，大六度5:3，小七度16:9。乐理中完全协和的音程包括纯一、纯八、纯五、纯四。完全协和音程的主观感受最佳。依此为例，小二度时，所述和声信号的频率为所述基频的
Figure PCTCN2018090099-appb-000002
大二度时，所述和声信号的频率为所述基频的
Figure PCTCN2018090099-appb-000003
小三度时，所述和声信号的频率为所述基频的
Figure PCTCN2018090099-appb-000004
大三度时，所述和声信号的频率为所述基频的
Figure PCTCN2018090099-appb-000005
纯四度时，所述和声信号的频率为所述基频的
Figure PCTCN2018090099-appb-000006
增四度时，所述和声信号的频率为所述基频的
Figure PCTCN2018090099-appb-000007
减五度时，所述和声信号的频率为所述基频的
Figure PCTCN2018090099-appb-000008
纯五度时，所述和声信号的频率为所述基频的
Figure PCTCN2018090099-appb-000009
小六度时，所述和声信号的频率为所述基频的
Figure PCTCN2018090099-appb-000010
大六度时，所述和声信号的频率为所述基频的
Figure PCTCN2018090099-appb-000011
小七度时，所述和声信号的频率为所述基频的
Figure PCTCN2018090099-appb-000012
本例中，所述和声信号的发生函数表达式为：Y＝Ky+b，且y＝asin(2*π*A*f*t)；其中，K表示频率的斜率，a表示和声信号的振幅，A表示谐波系数，f表示和声信号的频率，t表示时间。当高频噪声为恒频啸叫时，举例说明，我们知道了电机啸叫的一个恒定频率为f＝5050Hz，假设此信号为正弦信号。通过研究发现，对于这一频率的电机噪声信号，构造八度音程谐波成分的主观感受最好，于是我们就要生成频率为f/2＝2525Hz的正弦信号作为和声信号。其中，K为1，b为0。如果我们知道的电机啸叫是一个从3500Hz到4300Hz线性递增的频率，那么此时的发生函数即为上述的线性渐变的函数。
作为优选的方式，在生成上述和声信号时，还可考虑声环境中的作为目标噪声的高频噪声信号以外的其他噪声的频率，考虑和声信号是否与其他噪声成分是否相重叠，如重叠，则在构造该和声信号时，可不再构造重叠部分的频率成分。如此，避免了仅凭单一电机噪声信号的频率生成构造信号容易与其它非电机噪声成分因重叠、干涉等形成新的加强的噪声信号，导致引起的声环境品质下降问题，从而更好的改善声环境品质。
下边对所述步骤S22如何生成掩蔽信号进行具体解释说明。
关于该掩蔽信号的作用及其生成机理，解释如下：该掩蔽信号是这样起作用的，当一个较强的声音将一个较弱的声音隐蔽使较弱的声音不能听到的现象称为“掩蔽效应”。当同时聆听两个或者多个声音时，听觉系统会产生所谓的“掩蔽效应”，即每个纯音都会变得更听不清或者听不清，或者说这些纯音被部分地或完全的“掩蔽”掉，我们就是利用了这一特性，给高频噪声生成一个“掩蔽信号”，让这个“掩蔽信号”使高频噪声信号变得听不清，“掩蔽信号”的频率比噪声信号的要低一点。这样，一方面能起到掩蔽噪声信号的作用，另一方面，也能稍稍的降低尖锐度，至少不会增加尖锐度。以此，对于该掩蔽信号，一方面要求其频率要低于高频噪声信号的频率，另外，所述掩蔽信号的声压级与所述和声信号的声压级变化趋势一致。所谓变化趋势一致，指其与和声信号的声压级的趋势相匹配，比如，假设和声信号的声压级整体是线性减小的，则掩蔽信号也要相对于高频噪声信号的音高减小，但需要注意的是，其减小的幅度不一定要和和声信号的减小幅度保持一致。若和声信号的声压级是保持不变的，则掩蔽信号的声压级相对于高频噪声信号的声压级也保持一致。
如图7、图8中所示，其横轴为频率，纵轴为相对声压级；其中粗实线表示高频噪声信号，细实线为掩蔽信号，虚线表示为和声信号。如图7中所示，虚线所示的和声信号高频噪声信号的“八度”分谐波，分谐波的频率与高频噪声信号频率之间总是满足1:2的关系，掩蔽信号的频率比高频噪声信号的稍小一点。本例中，其分谐波的声压级整体呈线性减小的趋势，因此，掩蔽信号的声压级相对于高频噪声信号的声压级也相对小一些，以此用来掩蔽噪声信号。
如图8中所示，虚线所示的和声信号是高频噪声信号的奇数分谐波，分谐波的频率与“高频噪声信号的频率之间总是满足奇数的关系，掩蔽信号的频率比高频噪声信号的稍小一点。本例中分谐波信号的响度相同，但比噪声信号的小。将掩蔽信号的声压级设置为与高频噪声信号的声压级相同。
需要说明的是，不同的组合方式，其高频噪声信号、掩蔽信号和和声信号之间的频率关系、响度、谐波次数都是不同的，它们的主观感受也不尽相同。可以通过试验的方式挑 选出主观感受最佳的组合。此处不做详细表述，只是说明的具体的构造方法。
比如，该掩蔽信号可以通过如下方式获得：
预设N个频率的待选掩蔽信号，将所述待选掩蔽信号与所述高频噪声信号一一同步播放，进行主观评价，选出主观评价最好的待选掩蔽信号作为所述掩蔽信号；其中，所述预设的N个频率均小于所述高频噪声信号的频率；所述掩蔽信号的声压级与所述和声信号的声压级变化趋势一致。
或者，作为优选的方式，也可以将声压级也设置多个进行，组合进行主观评价。具体地，预设N个频率和M个预选声压级，将所述N个频率和M个预选声压级组合生成N*M个待选掩蔽信号；将所述N*M个待选掩蔽信号与高频噪声信号一一同步播放，进行主观评价，选出主观评价最好的待选掩蔽信号作为所述掩蔽信号；其中，所述待选掩蔽信号的声压级小于所述高频噪声信号的声压级；所述预设的N个频率均小于所述高频噪声信号的频率。
其中，所述N个频率的范围为【f0-a，f0-b】；其中，f0为所述高频噪声信号的频率，三者满足如下表达式：f0＞a＞b；其中，所述a，b为经验数值。
比如，假定上述表达式中，a＝150Hz，b＝50Hz；则在比高频噪声信号小【50，150】的频率范围内，选取N＝10，则以步长10Hz，生成10个待选掩蔽信号；将上述10个待选掩蔽信号与高频噪声信号一起播放进行主观评价，选出主观评价最好的一组。
步骤S3将所述和声掩蔽信号输入声音播放装置中播放，以输出降噪构造声音，对所述声环境进行降噪处理，比如，如在新能源车中，可通过声音播放装置播放声音对新能源车的高频电机噪声进行降噪处理。
本发明公开的该种主动降噪方法，适用于任何高频噪声环境中进行主动降噪处理，其一方面构造其高频噪声信号的分谐波信号作为和声信号，同时还在和声信号的基础上加入一与高频噪声信号的频率相近的掩蔽信号用来掩蔽高频噪声信号，加入分谐波可使整个频域之中噪声的高频成分所占有的比值降低，而高频成分的多少反映了烦躁度的大小，所以烦躁度是降低的。同时，加入掩蔽信号可使高频噪声信号变得不清晰，也会使得烦躁度的程度降低。如此，可以进一步提高其声环境的声品质。同时，该种方法简单易操作，成本小。
本发明第二实施例公开了主动降噪系统，如图9所示，包括如下模块：
高频噪声信号频率获取模块1，用于获取声环境中的高频噪声信号的频率；
和声掩蔽信号生成模块2，用于根据所述高频噪声信号的频率，构造生成和声掩蔽信 号；所述和声掩蔽信号包括和声信号和掩蔽信号；所述和声信号为所述高频噪声信号的分谐波；
和声掩蔽声音播放模块3，用于将所述和声掩蔽信号输入声音播放装置中播放，使所述和声掩蔽信号与声环境中的高频噪声信号相作用，以对所述声环境进行降噪处理。
该种主动降噪系统适用于各种需要进行高频降噪处理的声环境。特别是用于新能源车中对电机高频噪声进行降噪处理。
该高频噪声信号获取模块中，一般包括有声环境噪声采集装置，声环境噪声采集装置一般为麦克风，以新能源车为例，该麦克风可以为新能源车本身自带的装置，也可以为在原有新能源车自带麦克风的基础上，新增的麦克风。所述声环境噪声采集装置设置在新能源车的驾驶室或副驾驶室内。主要采集驾驶室和乘客所在空间中的声环境噪声。比如，一般将该声环境噪声采集装置安装在驾驶室和副驾驶室前的中控台上。或者也可将其安装在电机仓中靠近电机的位置。采集得到噪声信号后，还需要将高频噪声信号进行提取，以获得高频噪声信号的频率。
其中，如图10所示，所述和声掩蔽信号生成模块2具体包括：
和声信号生成子模块21，用于所述高频噪声信号的频率，构造生成和声信号；
掩蔽信号生成子模块22，用于根据所述高频噪声信号的频率，构造生成掩蔽信号；
复合模块23，用于将所述和声信号和掩蔽信号复合获得所述和声掩蔽信号。
其中，该和声掩蔽声音播放模块可以为本领域技术人员所知的各种可播放音频的设备，以系能源车领域为例，其可以为额外布置的扬声设备，其可以布置在驾驶员或者乘客所在的乘员仓中，比如驾驶室和副驾驶室内的中控台上，或者，也可将其声音播放装置布置在电机附近，即噪声源处，由此可以保证和声掩蔽信号播放后和电机噪声信号同源同途径，消除和声掩蔽信号在传播过程中产生的衰减等不确定因素，提高和声掩蔽信号与电机噪声信号进行融合后对车内环境(即声环境)的降噪效果。或者也可为新能源车内本身自带的扬声设备，比如和声掩蔽声音播放模块为新能源车内的车载音响。
需要说明的是，该主动降噪系统的其它具体实施方式可参见本发明上述第一实施例的主动降噪方法的具体实施方式，为免重复，此处不做赘述。
本发明公开的该种主动降噪系统，可应用于任何高频噪声环境中进行主动降噪处理，其一方面构造其高频噪声信号的分谐波信号作为和声信号，同时还在和声信号的基础上加入一与高频噪声信号的频率相近的掩蔽信号用来掩蔽高频噪声信号，加入分谐波可使整个频域之中噪声的高频成分所占有的比值降低，而高频成分的多少反映了烦躁度的大小，所以烦躁度是降低的。同时，加入掩蔽信号可使高频噪声信号变得不清晰，也会使得烦躁度 的程度降低。如此，可以进一步提高其声环境的声品质。同时，该种系统简单易实现，成本小。
如图11所示，本发明第三实施例公开了一种新能源车1000，其包括上述第二实施例中公开的主动降噪系统100。
因本例中仅对新能源车1000的主动降噪系统100进行改进，而不涉及其他结构和系统的改进，且该主动降噪系统100及其主动降噪方法已在上述第一实施例和第二实施例中进行说明，为免重复，不再赘述。
本发明公开的新能源车1000，由于其上设有主动降噪系统100，因此可对新能源车1000的高频电机噪声进行降噪处理，其一方面构造其高频噪声信号的分谐波信号作为和声信号，同时还在和声信号的基础上加入一与高频噪声信号的频率相近的掩蔽信号用来掩蔽高频噪声信号，加入分谐波可使整个频域之中噪声的高频成分所占有的比值降低，而高频成分的多少反映了烦躁度的大小，所以烦躁度是降低的。同时，加入掩蔽信号可使高频噪声信号变得不清晰，也会使得烦躁度的程度降低。如此，可以进一步提高新能源车内的声环境的声品质。同时，该种系统简单易实现，成本小。
以上所述仅为本发明的较佳实施例而已，并不用以限制本发明，凡在本发明的精神和原则之内所作的任何修改、等同替换和改进等，均应包含在本发明的保护范围之内。

Claims (14)

  1. 一种主动降噪方法，其特征在于，包括如下步骤：
    获取声环境中的高频噪声信号的频率；
    根据所述高频噪声信号的频率，构造生成和声掩蔽信号；所述和声掩蔽信号包括和声信号和掩蔽信号；所述和声信号为所述高频噪声信号的分谐波；
    将所述和声掩蔽信号输入声音播放装置中播放，以输出降噪构造声音，对所述声环境进行降噪处理。
  2. 根据权利要求1所述的新能源车的主动降噪方法，其特征在于，所述“获取声环境中的高频噪声信号的频率”具体包括如下步骤：
    采集声环境中的声环境噪声，获得噪声信号；
    然后从所述噪声信号中提取高频噪声信号，获得所述高频噪声信号的频率。
  3. 根据权利要求1或2所述的新能源车的主动降噪方法，其特征在于，所述“获取声环境中的高频噪声信号的频率”具体包括如下步骤：
    采集声环境中发出高频噪声的噪声源的相关运行参数，并根据所述运行参数获得对应的高频噪声信号的频率；所述运行参数与所述高频噪声信号的频率呈对应关系。
  4. 根据权利要求1至3任一项所述的新能源车的主动降噪方法，其特征在于，所述噪声源为新能源车，所述“获取声环境中的高频噪声信号的频率”具体包括如下步骤：采集新能源车的运行参数，并根据所述运行参数获取与运行参数相关联的高频噪声信号的频率；所述运行参数至少包括所述新能源车的电机转速，所述电机转速与所述高频噪声信号的频率呈对应关系。
  5. 根据权利要求1至4中任意一项所述的新能源车的主动降噪方法，其特征在于，所述“根据所述高频噪声信号的频率，构造生成和声掩蔽信号”具体包括如下步骤：
    根据所述高频噪声信号的频率，构造生成和声信号；
    根据所述高频噪声信号的频率，构造生成掩蔽信号；
    将所述和声信号和掩蔽信号复合获得所述和声掩蔽信号。
  6. 根据权利要求1至5中任意一项所述的新能源车的主动降噪方法，其特征在于，所述“根据所述高频噪声信号的频率，构造生成和声信号”具体包括如下步骤：
    根据所述高频噪声信号的频率通过调用预设的构造声音数据库以获取与所述高频噪声信号对应的和声信号；
    或者，根据所述高频噪声信号的频率通过发生函数获得所述电机噪声信号相对应的和声信号。
  7. 根据权利要求6所述的新能源车的主动降噪方法，其特征在于，所述“根据所述高频噪声信号的频率通过调用预设的构造声音数据库以获取与所述高频噪声信号对应的和声信号”具体包括如下步骤：
    根据所述高频噪声信号的频率判断所述高频噪声信号的所属频段；
    根据所述高频噪声信号的所属频段调用所述预设的构造声音数据库，以获取与所述高频噪声信号的所属频段相对应的和声信号；其中，所述预设的构造声音数据库中存储有多个和声信号样本，每个和声信号样本对应一个噪声频段，且包括与该噪声频段相对应的和声信号。
  8. 根据权利要求6或7所述的新能源车的主动降噪方法，其特征在于，所述预设的构造声音数据库通过如下步骤获得：
    对所述高频噪声信号进行频段划分以获得多个频段的标定噪声信号；
    选择任一频段的标定噪声信号，并根据音乐声学或心理声学原理对所选频段的标定噪声信号进行频率构造以生成多个预选和声信号；
    将所选频段的标定噪声信号分别与每个预选和声信号进行合成，以生成多个合成声音样本并输出，其中，每个合成声音样本的频率的所属频段均包括所述所选频段；
    根据预设评价方法对每个合成声音样本进行评分，并根据每个合成声音样本的评分结果从所述预选和声信号中获取一个作为所选频段的标定噪声信号相对应的和声信号。
  9. 根据权利要求5或8所述的新能源车的主动降噪方法，其特征在于，所述“根据所述高频噪声信号的频率，构造生成掩蔽信号”具体包括如下步骤：
    预设N个频率的待选掩蔽信号，将所述待选掩蔽信号与所述高频噪声信号一一同步播放，进行主观评价，选出主观评价最好的待选掩蔽信号作为所述掩蔽信号；其中，所述预设的N个频率均小于所述高频噪声信号的频率；所述掩蔽信号的声压级与所述和声信号的 声压级变化趋势一致。
  10. 根据权利要求5或8所述的新能源车的主动降噪方法，其特征在于，所述“根据所述高频噪声信号的频率，构造生成掩蔽信号”具体包括如下步骤：
    预设N个频率和M个预选声压级，将所述N个频率和M个预选声压级组合生成N*M个待选掩蔽信号；将所述N*M个待选掩蔽信号与高频噪声信号一一同步播放，进行主观评价，选出主观评价最好的待选掩蔽信号作为所述掩蔽信号；其中，所述待选掩蔽信号的声压级小于所述高频噪声信号的声压级；所述预设的N个频率均小于所述高频噪声信号的频率。
  11. 根据权利要求9或10所述的新能源车的主动降噪方法，其特征在于，所述N个频率的范围为【f0-a，f0-b】；其中，f0为所述高频噪声信号的频率，三者满足如下表达式：f0＞a＞b；其中，所述a，b为经验数值。
  12. 一种主动降噪系统，其特征在于，包括如下模块：
    高频噪声信号频率获取模块，用于获取声环境中的高频噪声信号的频率；
    和声掩蔽信号生成模块，用于根据所述高频噪声信号的频率，构造生成和声掩蔽信号；所述和声掩蔽信号包括和声信号和掩蔽信号；所述和声信号为所述高频噪声信号的分谐波；
    和声掩蔽声音播放模块，用于将所述和声掩蔽信号输入声音播放装置中播放，使所述和声掩蔽信号与声环境中的高频噪声信号相作用，以对所述声环境进行降噪处理。
  13. 根据权利要求12所述的主动降噪系统，其特征在于，所述和声掩蔽信号生成模块具体包括：
    和声信号生成子模块，用于所述高频噪声信号的频率，构造生成和声信号；
    掩蔽信号生成子模块，用于根据所述高频噪声信号的频率，构造生成掩蔽信号；
    复合模块，用于将所述和声信号和掩蔽信号复合获得所述和声掩蔽信号。
  14. 一种新能源车，其特征在于，包括权利要求12或13所述的主动降噪系统。
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