An acoustic metamaterial-based low-noise design and evaluation method for an electric drive system

Abstract

This invention belongs to the field of vibration and noise reduction technology for new energy vehicles, specifically involving a low-noise design and evaluation method for electric drive systems based on acoustic metamaterials. The method involves determining the peak intensity and frequency of the vibration and noise response of the electric drive system, identifying the significant area of ​​working deformation of thin-walled components in the electric drive system, and determining the installation position of the acoustic metamaterial based on this area. It also involves determining the design boundary parameters of the acoustic metamaterial, designing a local resonant element, artificially constructing the local resonant element, prototyping the acoustic metamaterial based on the artificial construction scheme of the local resonant element in step five, installing the acoustic metamaterial in the determined installation area, and verifying its noise reduction performance. Finally, it determines whether the artificial construction scheme parameters are optimal; if optimal, the acoustic metamaterial scheme is determined. This invention systematically proposes a method for using acoustic metamaterials to mitigate single-frequency noise radiated by the thin-walled structure of the electric drive system, and clarifies the precise selection method for the installation position of the acoustic metamaterial on the thin-walled structure of the electric drive system.

Description

Technical Field

[0001] This invention belongs to the field of vibration reduction and noise reduction technology for new energy vehicles, specifically relating to a low-noise design and evaluation method for electric drive systems based on acoustic metamaterials. Background Technology

[0002] Currently, the automotive industry is implementing a low-carbon strategy, with new energy and lightweighting being key strategies for achieving low-carbon goals. Vehicle vibration and noise (NVH) performance has become a crucial aspect of competition in the automotive market and a future development trend for automotive products. How to achieve lightweight design of the vehicle body while maintaining satisfactory NVH performance has become a focus of current research.

[0003] The biggest difference between new energy vehicles and traditional fuel vehicles is that the drive motor becomes part or all of the driving force. Without the masking effect of the engine and intake / exhaust system, the noise of the drive motor becomes noticeable, significantly impacting the sound quality inside the vehicle. Currently, people are placing increasingly higher demands on the NVH characteristics of electric drive systems. The electric drive assembly of new energy vehicles mainly consists of a motor, a motor controller, and a reducer. The motor end cover and motor controller cover are typically thin-walled structures with low modal frequencies. Under the influence of electromagnetic forces and other excitation forces, they are prone to generating significant single-frequency vibrations and noise peaks, which are transmitted into the vehicle through structural and airborne sound transmission paths, worsening the overall NVH performance.

[0004] Given the performance characteristics of conventional vibration and noise reduction materials, traditional solutions to single-frequency NVH problems typically require significant material weight and thickness to achieve the desired vibration and noise reduction effects. This contradicts the goals of vehicle lightweighting and cost reduction, thus necessitating the development of new materials and methods. In recent years, acoustic metamaterials technology, proposed and developed in the fields of acoustic physics and condensed matter physics, has provided new insights into solving single-frequency NVH problems. Acoustic metamaterials refer to novel composite structures formed by attaching specially designed oscillator units to a matrix structure in a specific manner. They possess extraordinary physical properties (such as negative equivalent mass density and negative equivalent modulus), enabling extraordinary manipulation of elastic waves and sound waves, thus making them highly valuable for applications in single-frequency vibration and noise reduction.

[0005] Currently, existing technologies include a motor controller cover NVH improvement structure that utilizes an arched structure to enhance the cover's modalities and vibration frequencies, preventing structural resonance and thus improving the system's NVH performance. Additionally, there are motor acoustic encapsulation and fixing devices that use acoustic wrapping to improve noise, vibration, and acoustic roughness throughout the vehicle's lifespan. There are also experimental studies exploring the feasibility and effectiveness of replacing the original aluminum cover of the motor assembly with damping composite materials; replacing the cover with a damping composite material has improved the vibration and noise issues of the motor assembly.

[0006] However, the noise reduction solutions selected in the aforementioned studies focused on traditional acoustic material wrapping, damping treatment, or structural optimization. Due to the inherent characteristics of traditional acoustic materials and structural designs, while achieving the NVH performance design target at the peak frequency of the electric drive system's vibration noise, it easily leads to over-design of NVH performance at other frequencies, thereby increasing weight and design costs. Therefore, how to conduct low-noise design of electric drive structures for new energy vehicles based on acoustic metamaterials, and achieve lightweight design while meeting NVH performance targets, is a pressing issue that needs to be addressed in this field. Summary of the Invention

[0007] To overcome the above problems, this invention provides a low-noise design and evaluation method for electric drive systems based on acoustic metamaterials; the noise reduction method used to control the single-frequency noise radiated by the thin-walled structure of the electric drive is acoustic metamaterial technology, and the installation position of the acoustic metamaterial is determined by the working deformation of the thin-walled structure of the electric drive.

[0008] The technical solution adopted in this invention is:

[0009] A low-noise design and evaluation method for electric drive systems based on acoustic metamaterials includes the following:

[0010] Step 1: Obtain the vibration and noise characteristics of the electric drive system, and determine the peak intensity and frequency of the vibration and noise response of the electric drive system;

[0011] Step 2: Obtain the working deformation of the thin-walled component of the electric drive system, identify the significant area of ​​working deformation of the thin-walled component of the electric drive system at the peak frequency, and determine the installation position of the acoustic metamaterial based on this area;

[0012] Step 3: Based on the installation space of the electric drive system, the project's lightweight design requirements, and the top-level parameters of cost indicators, combined with the peak intensity, peak frequency, and acoustic metamaterial installation location of the electric drive system's vibration and noise response obtained in Step 1 and Step 2, determine the design boundary parameters of the acoustic metamaterial.

[0013] Step 4: Design boundary parameters based on acoustic metamaterials to design local resonant arrays;

[0014] Step 5: Artificially construct the local resonant array designed in Step 4;

[0015] Step 6: Prototype acoustic metamaterial based on the local resonant oscillator man-made structure scheme in Step 5, install the acoustic metamaterial in the installation area determined in Step 2, and conduct noise reduction performance verification.

[0016] Step 7: Based on the experimental results of Step 6, determine whether the parameters of the local resonant oscillator designed in Step 4 and the artificial structure scheme in Step 5 are optimal, and determine whether the lightweight and cost indicators meet the requirements. If they are optimal, determine the acoustic metamaterial scheme; otherwise, proceed to Step 4.

[0017] Step one involves obtaining the vibration and noise characteristics of the electric drive system through simulation or real-world testing, and determining the peak intensity and frequency of the vibration and noise response of the electric drive system.

[0018] Step two involves obtaining the working deformation of the thin-walled components of the electric drive system through simulation or real-world testing, and identifying the significant area of ​​working deformation of the thin-walled components at the peak frequency.

[0019] In step four, the thickness, weight, natural frequency, and damping characteristics of the local resonant array are verified to meet the design boundaries using finite element method and multibody dynamics CAE. Otherwise, the array needs to be redesigned until it meets the design boundaries.

[0020] In step five, it is verified that the oscillator unit of the resonant array after the artificial arrangement does not change the inherent characteristics of the matrix structure itself. If the oscillator unit of the resonant array after the artificial arrangement changes the inherent characteristics of the matrix structure itself, the artificial arrangement scheme needs to be re-determined.

[0021] In step five, simulation or real experiments are conducted to verify that the oscillator unit of the resonant array after artificial manipulation does not change the inherent characteristics of the matrix structure itself.

[0022] The beneficial effects of this invention are:

[0023] This invention systematically proposes a method for mitigating single-frequency noise radiated by thin-walled electric drive structures using acoustic metamaterials, and clarifies the precise selection method for the installation location of acoustic metamaterials in the thin-walled electric drive structure. Given the precise frequency selection property of the acoustic metamaterials and the accurate determination of their installation location, a lightweight noise reduction scheme can be achieved while meeting NVH performance targets, minimizing over-design of the noise reduction scheme. Furthermore, previous research results indicate that, without significant changes in weight and cost, the vibration reduction and noise reduction scheme developed based on this invention can improve NVH performance by approximately 50%. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the content of the embodiments of the present invention and these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the electric drive radiation noise curve in Embodiment 2 of the present invention.

[0026] Figure 2 This is a design flowchart for Embodiment 2 of the present invention.

[0027] Figure 3 This is a schematic diagram of the working deformation of the thin-walled component of the electric drive system structure in Embodiment 2 of the present invention.

[0028] Figure 4 This is a schematic diagram of the installation position of the acoustic metamaterial in Embodiment 2 of the present invention.

[0029] Figure 5 This is a schematic diagram of the spring-mass-damping unit oscillator of Embodiment 2 of the present invention.

[0030] Figure 6 This is a schematic diagram of the hard-soft material block oscillator of Embodiment 2 of the present invention.

[0031] Figure 7 This is a schematic diagram of the local resonant oscillator man-made structure scheme of Embodiment 2 of the present invention. Detailed Implementation

[0032] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0033] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0034] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0035] In the description of this embodiment, the terms "upper," "lower," "left," and "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0036] Example 1

[0037] A low-noise design and evaluation method for electric drive systems based on acoustic metamaterials includes the following:

[0038] Step 1: Obtain the vibration and noise characteristics of the electric drive system, and determine the peak intensity and frequency of the vibration and noise response of the electric drive system;

[0039] Step 2: Obtain the working deformation of the thin-walled component of the electric drive system, identify the significant area of ​​working deformation of the thin-walled component of the electric drive system at the peak frequency, and determine the installation position of the acoustic metamaterial based on this area;

[0040] Step 3: Based on the installation space of the electric drive system, the project's lightweight design requirements, and the top-level parameters of cost indicators, combined with the peak intensity, peak frequency, and acoustic metamaterial installation location of the electric drive system's vibration and noise response obtained in Step 1 and Step 2, determine the design boundary parameters of the acoustic metamaterial.

[0041] Step four: Based on the acoustic metamaterial design boundary parameters such as thickness, weight, frequency, and installation location, design the local resonant array;

[0042] Step 5: Artificially construct the local resonant array designed in Step 4;

[0043] Step 6: Prototype acoustic metamaterial based on the local resonant oscillator man-made structure scheme in Step 5, install the acoustic metamaterial in the installation area determined in Step 2, and conduct noise reduction performance verification.

[0044] Step 7: Based on the experimental results of Step 6, determine whether the parameters of the local resonant oscillator designed in Step 4 and the artificial structure scheme in Step 5 are optimal, and determine whether the lightweight and cost indicators meet the requirements. If they are optimal, determine the acoustic metamaterial scheme; otherwise, proceed to Step 4.

[0045] Step one involves obtaining the vibration and noise characteristics of the electric drive system through simulation or real-world testing, and determining the peak intensity and frequency of the vibration and noise response of the electric drive system.

[0046] Step two involves obtaining the working deformation of the thin-walled components of the electric drive system through simulation or real-world testing, and identifying the significant area of ​​working deformation of the thin-walled components at the peak frequency.

[0047] In step four, the thickness, weight, natural frequency, and damping characteristics of the local resonant array are verified to meet the design boundaries using finite element method and multibody dynamics CAE. Otherwise, the array needs to be redesigned until it meets the design boundaries.

[0048] In step five, it is verified that the oscillator unit of the resonant array after the manual process will not change the inherent characteristics of the matrix structure itself, so as to avoid new acoustic vibration problems at lower frequencies in the thin-walled structure of the electric drive system. If the oscillator unit of the resonant array after the manual process changes the inherent characteristics of the matrix structure itself, the manual process scheme needs to be re-determined.

[0049] In step five, simulation or real experiments are conducted to verify that the oscillator unit of the resonant array after artificial manipulation does not change the inherent characteristics of the matrix structure itself.

[0050] Example 2

[0051] A low-noise design method for electric drive systems based on acoustic metamaterials includes the following:

[0052] (1) The local resonant oscillators used in acoustic metamaterials include spring-mass-damped oscillators and hard-soft material block oscillators;

[0053] (2) The local resonant oscillator is constructed in parallel to avoid new acoustic and vibration problems at lower frequencies in the thin-walled structure of the electric drive system.

[0054] A method for determining the mounting position of an acoustic metamaterial based on the working deformation of an electrically driven thin-walled structure includes the following steps:

[0055] (1) The working deformation of the electric drive thin-walled structure under electromagnetic force excitation was determined through experimental testing / finite element simulation analysis;

[0056] (2) Based on the significant area of ​​the single-frequency band working deformation of the electric drive system radiated noise, determine the installation position of the acoustic metamaterial.

[0057] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings:

[0058] (1) Through simulation / experiment, the vibration and noise characteristics of the electric drive system are obtained. Under the action of excitation forces such as electromagnetic force, the thin-walled structure of the electric drive system is prone to generate significant single-frequency vibration and noise peaks. Through step (1), the peak intensity and peak frequency of the vibration and noise response of the electric drive system can be determined. A typical schematic diagram of the noise radiation characteristics of an electric drive system without special noise reduction treatment is shown below. Figure 1 As shown, there is a significant peak value at a single frequency. Based on Figure 2 The method for low-noise design of electric drive systems based on acoustic metamaterials is shown to carry out low-noise design of electric drive structures for new energy vehicles, and achieve lightweight design while meeting NVH performance targets.

[0059] (2) The working deformation of thin-walled components in the electric drive system is obtained through simulation / experimentation. The working deformation of a typical thin-walled structure is as follows: Figure 3 As shown, the region of significant deformation of the thin-walled component in the electric drive system at the peak frequency is obtained, and the installation location of the acoustic metamaterial is determined. The typical correspondence between the installation location of the acoustic metamaterial and the region of significant deformation is shown in the figure. Figure 4 As shown.

[0060] (3) Based on the top-level parameters such as the installation space of the electric drive system and the lightweight design requirements of the project, and combined with the peak intensity, peak frequency and installation position of the vibration and noise of the electric drive system obtained in steps (1) and (2), the design boundary parameters of the acoustic metamaterial are determined.

[0061] (4) Based on the acoustic metamaterial design boundary parameters such as thickness, weight, frequency, and installation location, design local resonant elements (spring-mass-damped unit oscillators, rigid-soft material block oscillators, etc.). A typical spring-mass-damped unit oscillator is shown below. Figure 5 As shown, a typical hard-soft material block oscillator is as follows: Figure 6 As shown, CAE methods such as finite element method and multibody dynamics are used to verify that the thickness, weight, natural frequency and damping characteristics of the local resonant array meet the design boundaries.

[0062] (5) The local resonant array designed in step (4) is artificially constructed. Simulation / experimentation are used to verify that the artificially constructed oscillator unit does not change the inherent characteristics of the substrate structure, thus avoiding new acoustic and vibration problems in the thin-walled structure of the electric drive system at lower frequencies. This determines the artificial construction scheme, such as... Figure 7 As shown.

[0063] (6) Produce acoustic metamaterials based on the local resonant oscillator man-made structure scheme of step (5), install the acoustic metamaterials in the installation area determined in step (2), and carry out noise reduction performance verification.

[0064] (7) Based on the test results of step (6), determine whether the parameters of the local resonant oscillator designed in step (4) and the artificial structure scheme in step (5) are optimal, and determine whether the lightweight and cost indicators meet the requirements. If they are optimal, the acoustic metamaterial scheme can be determined; otherwise, proceed to step (4).

[0065] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the scope of protection of the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, any person skilled in the art can make equivalent substitutions or changes based on the technical solution and inventive concept of the present invention within the scope of the technology disclosed in the present invention. These simple modifications are all within the scope of protection of the present invention.

[0066] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0067] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A low-noise design and evaluation method for electric drive systems based on acoustic metamaterials, characterized in that, Includes the following: Step 1: Obtain the vibration and noise characteristics of the electric drive system, and determine the peak intensity and frequency of the vibration and noise response of the electric drive system; Step 2: Obtain the working deformation of the thin-walled component of the electric drive system, identify the significant area of ​​working deformation of the thin-walled component of the electric drive system at the peak frequency, and determine the installation position of the acoustic metamaterial based on this area; Step 3: Based on the installation space of the electric drive system, the project's lightweight design requirements, and the top-level parameters of cost indicators, combined with the peak intensity, peak frequency, and acoustic metamaterial installation location of the electric drive system's vibration and noise response obtained in Step 1 and Step 2, determine the design boundary parameters of the acoustic metamaterial. Step 4: Design boundary parameters based on acoustic metamaterials to design local resonant arrays; Step 5: Artificially construct the local resonant array designed in Step 4; Step 6: Prototype acoustic metamaterial based on the local resonant oscillator man-made structure scheme in Step 5, install the acoustic metamaterial in the installation area determined in Step 2, and conduct noise reduction performance verification. Step 7: Based on the experimental results of Step 6, determine whether the parameters of the local resonant oscillator designed in Step 4 and the artificial structure scheme in Step 5 are optimal, and determine whether the lightweight and cost indicators meet the requirements. If they are optimal, determine the acoustic metamaterial scheme; otherwise, proceed to Step 4.

2. The method for low-noise design and evaluation of an electric drive system based on acoustic metamaterials according to claim 1, characterized in that, Step one involves obtaining the vibration and noise characteristics of the electric drive system through simulation or real-world testing, and determining the peak intensity and frequency of the vibration and noise response of the electric drive system.

3. The method for low-noise design and evaluation of an electric drive system based on acoustic metamaterials according to claim 1, characterized in that, Step two involves obtaining the working deformation of the thin-walled components of the electric drive system through simulation or real-world testing, and identifying the significant area of ​​working deformation of the thin-walled components at the peak frequency.

4. The method for low-noise design and evaluation of an electric drive system based on acoustic metamaterials according to claim 1, characterized in that, In step four, the thickness, weight, natural frequency, and damping characteristics of the local resonant array are verified to meet the design boundaries using finite element method and multibody dynamics CAE. Otherwise, the array needs to be redesigned until it meets the design boundaries.

5. The method for low-noise design and evaluation of an electric drive system based on acoustic metamaterials according to claim 1, characterized in that, In step five, it is verified that the oscillator unit of the resonant array after the artificial arrangement does not change the inherent characteristics of the matrix structure itself. If the oscillator unit of the resonant array after the artificial arrangement changes the inherent characteristics of the matrix structure itself, the artificial arrangement scheme needs to be re-determined.

6. The method for low-noise design and evaluation of an electric drive system based on acoustic metamaterials according to claim 5, characterized in that, In step five, simulation or real experiments are conducted to verify that the oscillator unit of the resonant array after artificial manipulation does not change the inherent characteristics of the matrix structure itself.

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