New energy electric drive system noise evaluation method, evaluation system, evaluation electronic equipment and storage medium

Abstract

The invention provides a new energy electric drive system noise evaluation method and system, an evaluation electronic device and a storage medium. The method comprises the following steps: determining parameters of a tested electric drive system; acceleration and deceleration signals are measured through a vehicle speed signal to control the rotating speed and the torque of a motor of the electric drive system so as to truly reflect the actual use condition of the electric drive system. Acquiring a noise sound pressure signal of a corresponding frequency; converting the collected noise sound pressure signal into an A weighting sound pressure level; determining an equivalent continuous sound level according to the A-weighted sound pressure level; determining noise exposure according to the collected noise sound pressure signal; and performing noise evaluation according to the A-weighted sound pressure level and the noise exposure, and when the evaluation determines that noise pollution is generated, determining the noise pollution level according to the A-weighted sound pressure level and the equivalent continuous sound level. According to the method, the noise level of the new energy electric drive system can be evaluated more objectively.

Description

Technical Field

[0001] The present invention relates to the field of noise detection in new energy vehicles, and in particular to a noise assessment method, an assessment system, an assessment electronic device and a storage medium for a new energy electric drive system. Background Art

[0002] The measurement of product noise is generally carried out in an anechoic chamber (semi-anechoic chamber or full anechoic chamber) using a microphone. Some products allow testing in an open outdoor environment. The microphone is placed at the specified position of the product and connected to the acquisition instrument. The product is set to the specified specific working conditions. After the product is allowed to stabilize, its steady-state noise value is collected. Generally, the acquisition system will automatically calculate the corresponding A-weighted noise value based on the collected sound pressure. And evaluate whether the product meets the design requirements based on its noise value under certain specific working conditions. If necessary, the sound signal spectrum can be further analyzed, and the collected noise signal (generally a time domain signal) can be converted from the time domain to the frequency domain through Fourier transform to analyze abnormal noise that occurs in a specific frequency domain.

[0003] The existing noise test standards and their requirements generally require that the noise of a product under specific working conditions is lower than the limit or product design indicator. This one-size-fits-all approach may not be able to truly evaluate its noise level. Because products have a lot of working conditions, especially new energy electric drive systems, the motor speed range is very wide, generally 0-15000r / min, up to 25000r / min or even higher, the torque is generally 0-300Nm, up to 600Nm or even higher. Obviously, it is unrealistic to test all working conditions, and the proportion of working time under each working condition is different. Even if the rated speed and rated torque are specified by the manufacturer, there are very few scenarios in which the electric drive system actually works under the rated working conditions during driving. Therefore, no working condition can represent the typical working condition of the electric drive system, and selecting individual working conditions to test the noise of the electric drive system cannot truly reflect the noise level of the electric drive system. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a new energy electric drive system noise assessment method, assessment system, assessment electronic equipment and storage medium. It is a new energy electric drive system noise assessment method based on the Chinese Automobile Driving Condition (CLTC), which is a typical driving condition for Chinese light vehicles on highways. It introduces the statistical method of equivalent continuous sound level, noise exposure and noise calculation method of noise evaluation number NR, and weights the noise values ​​of different conditions according to the actual proportion of the conditions, so as to more objectively evaluate the noise level of the new energy electric drive system. And it can judge whether the noise of this electric drive system will cause damage to human hearing according to the set driving conditions.

[0005] The present invention achieves the above technical objectives through the following technical means.

[0006] A method for evaluating noise of a new energy electric drive system comprises the following steps:

[0007] Determine the parameters of the electric drive system under test;

[0008] The speed of the electric drive system motor and the torque of the dynamometer are controlled by the vehicle speed signal and acceleration / deceleration signal of the test condition to truly reflect the actual working condition of the electric drive system; the noise sound pressure signal within the set frequency range is collected;

[0009] Convert the collected noise sound pressure signal into A-weighted sound pressure level;

[0010] Determine the equivalent continuous sound level based on the A-weighted sound pressure level;

[0011] Determine the noise exposure amount according to the collected noise sound pressure signal;

[0012] Noise assessment is carried out based on the A-weighted sound pressure level and noise exposure. When the assessment determines that noise pollution occurs, the noise pollution level is determined based on the A-weighted sound pressure level and the equivalent continuous sound level.

[0013] Furthermore, the collected noise sound pressure signal is converted into the A-weighted sound pressure level, which is calculated specifically according to the following formula:

[0014]

[0015] Where: τ is the exponential time constant of the time weighting F or S; T is the length of a certain period of time; p A (t) is the noise sound pressure signal collected; p 0 is the reference sound pressure.

[0016] Furthermore, the equivalent continuous sound level is determined according to the A-weighted sound pressure level, specifically:

[0017] The calculation formula of discrete equivalent continuous sound level is:

[0018]

[0019] Where: N is the total number of sound levels measured, L AT，i (t) is the A-weighted sound level at the i-th sampling point; there are n sampling points in the semi-anechoic chamber, and the A-weighted sound pressure level at the i-th sampling point is recorded as L AT，i (t); L eq is the equivalent continuous sound level.

[0020] Furthermore, the noise exposure is determined according to the collected noise sound pressure signal, specifically:

[0021]

[0022] Where p(j) is the noise sound pressure signal of the jth sampling, m is the total number of samples, Δt is the sampling interval; E is the noise exposure.

[0023] Furthermore, the rules for noise assessment based on A-weighted sound pressure level and noise exposure are as follows:

[0024] When the A-weighted sound pressure level L AT，i (t) is less than or equal to the first set value, the noise is assessed as not exceeding the specified requirements;

[0025] When the A-weighted sound pressure level L AT，i (t) is greater than the first set value, the equivalent continuous sound level L is calculated eq and noise exposure E,

[0026] When the noise exposure E is less than or equal to the second set value, the noise is assessed as not exceeding the prescribed requirements; when the noise exposure E is greater than the second set value, the noise is assessed as generating noise pollution, and the noise pollution level is determined based on the A-weighted sound pressure level and the equivalent continuous sound level.

[0027] Furthermore, the noise pollution level is determined based on the A-weighted sound pressure level and the equivalent continuous sound level, specifically:

[0028] The noise pollution level is the physical quantity L of the noise variation range. NP , the calculation formula is:

[0029]

[0030] L NP =L eq +Kσ

[0031] Where: is the arithmetic mean of the A-weighted sound levels of all sampling points during the entire sampling time, L AT，i (t) is the instantaneous A sound level at the i-th sampling point, n is the total number of sampling points; σ is the standard deviation of the instantaneous sound level during this noise sampling process, and K is a constant.

[0032] A new energy electric drive system noise assessment system comprises an acquisition module, an A-weighted sound calculation module, an equivalent continuous sound level calculation module, a noise exposure calculation module, a noise pollution level calculation module and a judgment module; the acquisition module is used to acquire noise sound pressure signals; the A-weighted sound pressure level calculation module is used to output the A-weighted sound pressure level according to the noise sound pressure signal; the equivalent continuous sound level calculation module outputs the equivalent continuous sound level according to the A-weighted sound pressure level; the noise exposure calculation module outputs the noise exposure according to the noise sound pressure signal; the noise pollution level calculation module outputs the noise pollution level according to the A-weighted sound pressure level and the equivalent continuous sound level; the judgment module is provided with a first set value and a second set value, and the judgment module judges the size of the A-weighted sound pressure level and the first set value, and judges the size of the noise exposure and the second set value, and outputs the judgment result according to the judgment result.

[0033] An evaluation electronic device comprises a processor and a memory, wherein the memory stores computer-readable instructions, and when the computer-readable instructions are executed by the processor, the steps in the new energy electric drive system noise evaluation method are executed.

[0034] A storage medium stores a computer program, which, when executed by a processor, runs the steps in the new energy electric drive system noise assessment method.

[0035] The beneficial effects of the present invention are:

[0036] The present invention provides a new energy electric drive system noise assessment method, assessment system, assessment electronic equipment and storage medium. It is a new energy electric drive system noise assessment method based on the Chinese car driving condition (CLTC), which is a typical driving condition of Chinese light vehicles on highways, and introduces a statistical method for equivalent continuous sound level, noise exposure and noise calculation method for noise evaluation number NR. The noise values ​​of different conditions are weighted according to the actual proportion of the conditions, so as to more objectively evaluate the noise level of the new energy electric drive system. And it can be judged whether the noise of this electric drive system will cause damage to human hearing according to the set driving conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. The drawings described below are some embodiments of the present invention. For ordinary technicians in this field, it is obvious that other drawings can be obtained based on these drawings without paying any creative work.

[0038] Figure 1 The figure is a flow chart of the noise assessment method of the new energy electric drive system described in the present invention.

[0039] Figure 2 This is a schematic diagram of the layout of the noise collection sensors described in the present invention.

[0040] Figure 3 This is the CLTC-P operating curve described in the present invention.

[0041] Figure 4 This is a schematic diagram of the noise assessment system for the new energy electric drive system described in the present invention. DETAILED DESCRIPTION

[0042] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0043] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "axial", "radial", "vertical", "horizontal", "inner", "outer" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0044] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0045] like Figure 1 As shown, the noise assessment method of the new energy electric drive system of the present invention specifically includes the following steps:

[0046] S01: Parameter setting. The data acquisition system is connected to the LMS system to set the relevant parameters for testing and sampling, and the data cache size and location. The dynamometer is connected to set the dynamometer parameters according to the measured electric drive system parameters, such as torque range, speed range, torque accuracy, maximum torque dynamic response time and other parameters, so that the dynamometer can respond to load instructions more quickly and control accuracy.

[0047] S02: Collect data. The data acquisition system calculates the speed, torque and other parameters of the electric drive system according to the requirements of the CLTC test conditions for vehicle speed and acceleration and deceleration, sends a speed command to the electric drive system, and sends a specific load torque command to the dynamometer. It also reads the noise pressure and other data of the corresponding frequency collected by the LMS in real time and saves it in the local database until the end of the test.

[0048] S2.1: Noise test environment construction

[0049] The noise collection site of the present invention is a semi-anechoic chamber, and sound-absorbing materials are arranged on the surrounding walls and the roof. The anechoic chamber uses the floor as the reflective surface and is a room that simulates a semi-free space. The background noise of this anechoic chamber is less than 15dB (A). The collection equipment adopts the LMS SCM2E05 data acquisition system with a maximum sampling frequency of 200kHz and a noise frequency collection range of 20 to 20kHz, which ensures that the noise value of the motor at different rotation angles can be accurately collected when the motor rotates at high speed, which is helpful for model analysis and improving the accuracy of noise collection. The collection system is connected to the LMS data acquisition system via USB to collect noise signals. The industrial computer is connected to the dynamometer via the TCP / IP network protocol, and sends instructions to the dynamometer via the Modbus TCP communication protocol and reads the status of the dynamometer (such as current torque, speed, etc.). Testing and collection such as Figure 2 This figure is only a schematic diagram of noise collection. In actual testing, corresponding changes need to be made according to the test conditions, such as microphone layout, distance from the motor, etc.

[0050] Taking into account the impact of noise from the dynamometer and other components on the test results, a common practice is to move the dynamometer and other noisy components outside the semi-anechoic chamber to minimize their impact on the test results.

[0051] S2.2: Selection of sampling conditions

[0052] The speed range and torque range of the energy electric drive system are relatively wide, and the combination of the two has more working conditions, so the selection of its working conditions needs to be targeted and representative. The present invention is based on the CLTC (China Light-duty Vehicle Test Cycle) endurance standard, that is, the working conditions of the China light-duty vehicle test cycle, such as Figure 3As shown in the CLTC-P operating curve, the noise value (time domain signal) of the test electric drive system at each moment during the entire test process.

[0053] S2.3: Signal Acquisition

[0054] The data acquisition system is connected to the LMS system through a USB port and uses the Standard Commands for Programmable Instruments (SCPI) protocol for communication. Before the test, the control system box LMS system sends parameter setting commands, such as setting the noise acquisition frequency range, sampling time interval, cache size and other parameters. When data acquisition is required, the data acquisition system sends a command to start acquisition, waits for the data returned by the LMS, reads the LMS system cache data, and parses and saves it to the local computer hard disk.

[0055] Test condition processing. During the test, the motor is controlled according to the test speed and acceleration and deceleration specified in Table 1 (CLTC-P working condition curve statistical characteristics) and Appendix A.1 (CLTC-P working condition data) of the national standard GB / T 38146.1-2019.

[0056] Motor speed calculation. The required motor speed can be calculated based on the test speed, tire radius, and reduction ratio of the single-speed reducer specified in the standard. As shown in Formula 1 and Formula 2, the calculation formula for motor speed and vehicle speed can be obtained. The acquisition system automatically calculates the required speed according to the specified vehicle speed information and controls the motor to operate at the equivalent vehicle speed specified in the standard.

[0057]

[0058]

[0059] Where: V m is the motor speed, in revolutions per minute (r / min); V is the vehicle speed, in kilometers per hour (km / h); i 0 is the reduction ratio of the electric vehicle single-speed reducer, without units; r is the tire radius, in meters (m).

[0060] Motor torque calculation. As shown in formula 3. The acceleration and deceleration control calculates the torque required by the motor through parameters such as vehicle mass and tire radius, and outputs the signal to the dynamometer, giving the load torque required by the motor and monitoring the real-time speed and torque of the electric drive system to verify the test conditions of the electric drive system.

[0061] The acceleration and deceleration control uses parameters such as vehicle mass, tire radius, and friction coefficient to calculate the torque required by the motor. Ignoring factors such as tire deformation and the vehicle's head tilt when accelerating and its head nodding when decelerating, the torque of the motor during acceleration can be calculated, as shown in Formula 3.

[0062] T 0 =(mgμ+mJ c )r Formula 3

[0063] Where: m is the fully loaded mass of the vehicle, in kilograms (kg); g is the acceleration due to gravity, in meters per second squared (m / s 2 ), μ is the friction coefficient, J c is the acceleration required for the test, in meters per second squared (m / s 2 );r is the tire radius, in meters (m).

[0064] During the test, the speed and torque of the electric drive system motor are controlled by measuring the vehicle speed signal and the acceleration and deceleration signal, which truly reflects the actual working conditions of the electric drive system. The noise sound pressure signal of the corresponding frequency collected by LMS.

[0065] S03: Data Processing

[0066] S3.1: Calculate the A-weighted value of a noise

[0067] The collected sound pressure signal is converted into the A-weighted sound pressure level, as shown in Formula 4.

[0068]

[0069] Where: τ is the exponential time constant of the time weighting F or S; T is the length of a certain period of time; p A (t) is the A-weighted instantaneous sound pressure, that is, the collected noise sound pressure signal; p 0 is the reference sound pressure (2×10 -5 Pa).

[0070] There are n sampling points in the semi-anechoic chamber, and the A-weighted sound pressure level of the i-th sampling point is recorded as L AT，i (t), calculated using Formula 4, i∈[1,n].

[0071] In the above formula, the numerator of the function formula for logarithmic operation is the root mean square value of the frequency-weighted sound pressure weighted by exponential time at the observation time t.

[0072] S3.2: Determine the Equivalent Continuous Sound Level

[0073] The permanent magnet synchronous motor of the new energy electric drive system has a wide range of speed and torque, but there is no standard working condition to measure the noise of the electric drive system. However, even if the electric drive system can be specified as its standard working condition under a certain working condition, the use scenarios of automobiles are diverse and complex, and there are very few scenarios where it works under standard working conditions. It is obviously inappropriate to use the noise value under this working condition as the evaluation of the noise of the new energy electric drive system. Therefore, based on the energy equivalence principle of human ear damage, a method for calculating the equivalent continuous sound level is proposed to evaluate the noise of new energy electric drive systems. This method uses the noise energy averaging method to evaluate the impact of noise on people, that is, at a certain position in the sound field, the energy averaging method is used for a certain period of time to use the intermittently changing A sound level as a calculated average A sound level to represent the noise level during that period of time, and this A sound level is called the equivalent continuous A sound level for this period of time, that is

[0074]

[0075] Where: p A (t) is the instantaneous A-weighted sound pressure; p 0 is the reference sound pressure; L AT (t) is the A-weighted sound pressure level in dB; T is the length of a period of time.

[0076] The above formula is the equivalent continuous A-weighted sound level calculated under ideal and continuous noise function conditions. The noise data collected in the actual test are all discontinuous discrete data. Since the sampling time intervals are equal, according to the principle of calculus, the changes in the noise signal during the two sampling intervals are ignored (because the sampling time is short, the national mandatory standard GB 1495-2002 Automobile Acceleration Vehicle Noise Limits and Measurement Methods stipulates that the reading time interval should not be greater than 30ms, and the sampling interval in the actual test is shorter). The calculation formula for converting the above formula into a discrete equivalent continuous sound level is:

[0077]

[0078] Where: N is the total number of sound levels measured, L AT，i (t) is the A-weighted sound level at the i-th sampling point. For continuous stable noise, the equivalent continuous sound level is equal to the measured A-weighted sound level.

[0079] S3.3: Determine noise exposure

[0080] Although S3.2 can preliminarily derive the equivalent continuous sound level of the new energy electric drive system during normal driving (which can be considered as the equivalent noise of the electric drive system under all working conditions), whether this noise will affect human hearing requires the introduction of the concept of noise exposure. Because a person works in a certain noise environment, that is, when exposed to a noise environment, the impact of noise on people is not only related to the intensity of the noise, but also to the duration of noise exposure. For this reason, the noise exposure amount is proposed and represented by E, with the unit of Pa2·h (Pa2·hour). The noise exposure amount E is defined as the time integral of the square of the A-weighted sound pressure value of the noise, that is:

[0081]

[0082] Where: t 1 and t 2 is the moment of measuring the time interval, p A (t) is the A-weighted instantaneous sound pressure. If p A (t) remains constant during the trial period, then:

[0083] E=p 2 (t)(t 2 -t 1 )(Formula 8)

[0084] Obviously, the above two formulas are under ideal conditions, but in reality, the sound pressure cannot remain constant during noise testing, and the sound pressure may not be expressed using a continuous function. Therefore, in the actual noise collection and processing process of the project, the collected sound pressure is discrete, but generally its sampling interval is fixed, so the general processing formula is:

[0085]

[0086] Where p(j) is the sound pressure of the jth sampling, m is the total number of samples, and Δt is the sampling interval;

[0087] S3.4: Noise pollution level

[0088] The introduction of equivalent continuous sound pressure is equivalent to finding the average value of all noise in terms of intensity. From a statistical point of view, it is also necessary to introduce variance or standard deviation to reflect the discreteness of the data. For noise problems, it has practical significance. Obviously, for noises of equivalent continuous sound level of the same intensity, the drastic changes in noise are more likely to cause trouble to people. Therefore, the physical quantity L of the noise change amplitude is introduced. NP , and its calculation formula is:

[0089]

[0090] L NP =L eq +Kσ(Formula 11)

[0091] Where: is the arithmetic mean of the A-weighted sound levels of all sampling points during the entire sampling time, L AT，i (t) is the instantaneous A sound level at the ith sampling point, and n is the total number of sampling points. σ is the standard deviation of the instantaneous sound level during this noise sampling process, and K is a constant, which is 2.56 when calculating traffic and aircraft noise values.

[0092] S04: Noise Pollution Assessment

[0093] Calculate the A-weighted value, equivalent continuous sound level, noise exposure, and noise pollution level at different times and sampling points in turn. Evaluate according to the following logic:

[0094] When the A-weighted sound pressure level L AT，i (t) is less than or equal to the first set value, then it is judged that the noise does not exceed the specified requirement;

[0095] When the A-weighted sound pressure level L AT，i (t) is greater than the first set value, then the equivalent continuous sound level L is calculated eq and noise exposure E,

[0096] When the noise exposure E is less than or equal to the second set value, it is judged that the noise does not exceed the specified requirements; when the noise exposure E is greater than the second set value, the noise pollution level is calculated and the noise pollution level is output, that is, the physical quantity L of the noise change amplitude NP .

[0097] like Figure 1 As shown, the noise assessment method of the new energy electric drive system of the present invention can also be performed according to the following steps:

[0098] a. Parameter setting and data collection are the same as steps S01 and S02.

[0099] b. Calculate the A-weighted values ​​at different times and sampling points. When the A-weighted sound pressure level L AT，i (t) is less than or equal to the first set value, then it is judged that the noise does not exceed the specified requirement;

[0100] c. When the A-weighted sound pressure level L AT，i (t) is greater than the first set value, then the equivalent continuous sound level L is calculated eq and noise exposure amount E. When the noise exposure amount E is less than or equal to the second set value, it is judged that the noise does not exceed the specified requirement;

[0101] d. When the noise exposure E is greater than the second set value, the noise pollution level is calculated and output, that is, the physical quantity L of the noise change amplitude NP .

[0102] The first set value and the second set value in the method are determined according to a historical database and on-site working conditions.

[0103] like Figure 4 As shown, the noise assessment system of the new energy electric drive system of the present invention includes an acquisition module, an A-weighted sound calculation module, an equivalent continuous sound level calculation module, a noise exposure calculation module, a noise pollution level calculation module and a judgment module. The acquisition module is used to collect noise sound pressure signals; the A-weighted sound pressure level calculation module is used to output the A-weighted sound pressure level according to the noise sound pressure signal; the equivalent continuous sound level calculation module outputs the equivalent continuous sound level according to the A-weighted sound pressure level; the noise exposure calculation module outputs the noise exposure according to the noise sound pressure signal; the noise pollution level calculation module outputs the noise pollution level according to the A-weighted sound pressure level and the equivalent continuous sound level; the judgment module is provided with a first set value and a second set value, and the judgment module is used to judge the size of the A-weighted sound pressure level and the first set value, and to judge the size of the noise exposure and the second set value, and output the judgment result according to the judgment result.

[0104] When the A-weighted sound pressure level L AT，i (t) is less than or equal to the first set value, then the module output noise is judged to be within the specified requirements;

[0105] When the A-weighted sound pressure level L AT，i (t) is greater than the first set value, and the noise exposure amount E is less than or equal to the second set value, then the module output noise does not exceed the specified requirements;

[0106] When the A-weighted sound pressure level L AT，i (t) is greater than the first set value, and the noise exposure E is greater than the second set value, then the module output noise exceeds the specified requirements.

[0107] In the above three situations, the noise collection and assessment system can further perform continuous equivalent noise, noise exposure and noise pollution level according to the settings to evaluate the noise level more accurately.

[0108] An evaluation electronic device comprises a processor and a memory, wherein the memory stores computer-readable instructions. When the computer-readable instructions are executed by the processor, the steps in the new energy electric drive system noise evaluation method are executed.

[0109] A storage medium stores a computer program, which, when executed by a processor, runs the steps in the new energy electric drive system noise assessment method.

[0110] It should be understood that although this specification is described according to various embodiments, not every embodiment contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0111] The series of detailed descriptions listed above are only specific descriptions of feasible embodiments of the present invention. They are not intended to limit the scope of protection of the present invention. All equivalent embodiments or changes that do not deviate from the technical spirit of the present invention should be included in the scope of protection of the present invention.

Claims

1. A noise assessment method for a new energy electric drive system, characterized in that: The steps include: Determine the parameters of the electric drive system under test; The speed of the electric drive system motor and the torque of the dynamometer are controlled by the vehicle speed signal and acceleration / deceleration signal of the test condition to truly reflect the actual working condition of the electric drive system; the noise sound pressure signal within the set frequency range is collected; Convert the collected noise sound pressure signal into A-weighted sound pressure level; Determine the equivalent continuous sound level based on the A-weighted sound pressure level; Determine the noise exposure amount according to the collected noise sound pressure signal; Noise assessment is carried out based on the A-weighted sound pressure level and noise exposure. When the assessment determines that noise pollution occurs, the noise pollution level is determined based on the A-weighted sound pressure level and the equivalent continuous sound level.

2. The noise assessment method for a new energy electric drive system according to claim 1 is characterized in that: The collected noise sound pressure signal is converted into the A-weighted sound pressure level, which is calculated according to the following formula: Where: τ is the exponential time constant of the time weighting F or S; T is the length of a certain period of time; p A (t) is the collected noise sound pressure signal; p0 is the reference sound pressure.

3. The noise assessment method of new energy electric drive system according to claim 1 is characterized in that: Determine the equivalent continuous sound level based on the A-weighted sound pressure level, specifically: The calculation formula of discrete equivalent continuous sound level is: Where: N is the total number of sound levels measured, L AT，i (t) is the A-weighted sound level at the i-th sampling point; there are n sampling points in the semi-anechoic chamber, and the A-weighted sound pressure level at the i-th sampling point is recorded as L AT，i (t); L eq is the equivalent continuous sound level.

4. The noise assessment method for a new energy electric drive system according to claim 1 is characterized in that: The noise exposure is determined based on the collected noise sound pressure signal, specifically: Where p(j) is the noise sound pressure signal of the jth sampling, m is the total number of samples, Δt is the sampling interval; E is the noise exposure.

5. The noise assessment method for a new energy electric drive system according to claim 1 is characterized in that: The specific rules for noise assessment based on A-weighted sound pressure level and noise exposure are: When the A-weighted sound pressure level L AT，i (t) is less than or equal to the first set value, the noise is assessed as not exceeding the specified requirements; When the A-weighted sound pressure level L AT，i (t) is greater than the first set value, the equivalent continuous sound level L is calculated eq and noise exposure E, When the noise exposure E is less than or equal to the second set value, the noise is assessed as not exceeding the prescribed requirements; when the noise exposure E is greater than the second set value, the noise is assessed as generating noise pollution, and the noise pollution level is determined based on the A-weighted sound pressure level and the equivalent continuous sound level.

6. The noise assessment method of new energy electric drive system according to claim 1 is characterized in that: The noise pollution level is determined based on the A-weighted sound pressure level and the equivalent continuous sound level, specifically: The noise pollution level is the physical quantity L of the noise variation range. NP , the calculation formula is: L NP =L eq +Kσ Where: is the arithmetic mean of the A-weighted sound levels of all sampling points during the entire sampling time, L AT，i (t) is the instantaneous A sound level at the i-th sampling point, n is the total number of sampling points; σ is the standard deviation of the instantaneous sound level during this noise sampling process, and K is a constant.

7. An evaluation system for the noise evaluation method of a new energy electric drive system according to claims 1-6, characterized in that: It includes a collection module, an A-weighted sound calculation module, an equivalent continuous sound level calculation module, a noise exposure calculation module, a noise pollution level calculation module and a judgment module; the collection module is used to collect noise sound pressure signals; The A-weighted sound pressure level calculation module is used to output the A-weighted sound pressure level according to the noise sound pressure signal; the equivalent continuous sound level calculation module outputs the equivalent continuous sound level according to the A-weighted sound pressure level; the noise exposure amount calculation module outputs the noise exposure amount according to the noise sound pressure signal; The noise pollution level calculation module outputs the noise pollution level according to the A-weighted sound pressure level and the equivalent continuous sound level; the judgment module is provided with a first set value and a second set value, and the judgment module judges the size of the A-weighted sound pressure level and the first set value, and judges the size of the noise exposure amount and the second set value, and outputs the judgment result according to the judgment result.

8. An electronic device for evaluating the performance of a device, characterized in that: The method comprises a processor and a memory, wherein the memory stores computer-readable instructions. When the computer-readable instructions are executed by the processor, the steps in the noise assessment method for a new energy electric drive system as described in any one of claims 1 to 7 are executed.

9. A storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by the processor, the steps of the new energy electric drive system noise assessment method as described in any one of claims 1 to 7 are executed.

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