Electric drive system offline testing methods and testing system

Abstract

This invention relates to the field of rotating machinery testing methods, specifically to a method and system for offline testing of electric drive systems. The method includes: setting test conditions for the electric drive system; sampling multiple electric drive systems according to the set conditions; constructing a sample order spectrum for each electric drive system based on the sampled data; constructing an average order spectrum based on all sample order spectra; obtaining a differential order spectrum for each electric drive system based on the sample order spectrum and the average order spectrum; and analyzing the differential order spectrum of each electric drive system to determine whether the system exhibits abnormal vibration or noise. This application's offline testing method for electric drive assemblies analyzes the vibration and noise of the electric drive assembly using differential order spectra, enabling precise determination of whether the vibration and noise of the electric drive assembly is within acceptable limits. It provides a thorough evaluation and analysis of the characteristics of local regions, resulting in a more accurate evaluation of the vibration and noise of the entire electric drive assembly.

Description

Technical Field

[0001] This invention relates to the field of rotating machinery testing methods, specifically to a method and system for offline testing of an electric drive system. Background Technology

[0002] The electric drive assembly is a key component of electric and hybrid vehicles, primarily responsible for converting electrical energy into mechanical energy to drive the vehicle's tires. The electric drive assembly comprises several key components, which can generally be divided into the following main parts:

[0003] 1. Electric motor

[0004] The electric motor converts electrical energy into mechanical energy to drive the vehicle; the electric motor can be an AC motor (such as an asynchronous motor or a permanent magnet synchronous motor) or a DC motor.

[0005] 2. Battery pack

[0006] It stores electrical energy and supplies it to the electric motor; battery packs are typically composed of multiple battery cells, and common types include lithium-ion batteries and solid-state batteries.

[0007] 3. Inverter

[0008] The inverter converts direct current (provided by the battery) into alternating current to drive the motor; it also controls the motor's speed and torque.

[0009] Electric drive assemblies involve many rotating components, such as motors and gear structures. These rotating components generate vibration and noise during use. Therefore, to ensure that the vibration and noise of the electric drive assembly meets design requirements after it rolls off the production line, vibration and noise testing is usually performed. This testing typically utilizes order analysis. For example, an existing technology titled "A Noise Evaluation Method for a Gear Reducer" proposes a noise evaluation method following these steps: setting the speed parameters of the gear reducer, inputting standard sample data, setting preprocessing parameters, and setting evaluation criteria; acquiring the sound signal, vibration signal, and speed signal of the gear reducer; storing the acquired sound signal, vibration signal, and speed signal as test data, and storing the standard sample data; resampling the vibration signal at equal angles, and performing order analysis on the resampling data to obtain order analysis data; performing FFT transformation on the order analysis data to generate an order graph of the test data, comparing the order graph parameters of the test data with those of the standard sample data, and deriving an evaluation level based on the evaluation criteria; and displaying the evaluation level. This method is relatively simple and can evaluate the noise level of a speed reducer, since a speed reducer is actually a rotating component, and the order analysis method is suitable for evaluating the noise of rotating components.

[0010] However, this method also has some problems. The main issue is that its order analysis is too simplistic. Specifically, the method of comparing the order plot parameters of the test data and the order plot parameters of the standard sample data to derive the evaluation level according to the evaluation criteria includes: comparing the order spectrum of the preprocessed parameters with that of the standard sample data; selecting orders related to the preprocessed parameters for comparison; obtaining the similarity of each order point; taking the average of the similarities; obtaining the deviation rate of the standard samples; and obtaining the evaluation level according to the set evaluation criteria. This evaluation method essentially compares the collected data with standard data and then judges the noise level. The evaluation test method is too broad and imprecise, ignoring the characteristics of local intervals. It may have insufficient consistency control in specific problems, leading to inaccurate noise testing and failing to truly reflect the problems of the rotating component. Summary of the Invention

[0011] The purpose of this application is to address the shortcomings of the aforementioned background technology and to provide a method and system for offline testing of electric drive systems.

[0012] The technical solution of this application is: a method for offline testing of an electric drive system, comprising,

[0013] Set the test conditions for the electric drive system;

[0014] Samples were taken from multiple electric drive systems according to the set operating conditions;

[0015] Construct sample order spectral diagrams for each electric drive system based on the sampled data;

[0016] An average order spectrum is constructed based on the order spectrum of all samples;

[0017] The differential order spectrum of each electric drive system is obtained based on the sample order spectrum and the average order spectrum of each electric drive system;

[0018] The difference order spectrum of each electric drive system is analyzed to determine whether there is abnormal vibration and noise in the electric drive system.

[0019] According to the method for offline testing of an electric drive system provided in this application, the method for setting the test conditions of the electric drive system includes: setting the rotational speed, torque and speed of the rotating components of the electric drive assembly to form multiple operating conditions.

[0020] According to the method for offline testing of an electric drive system provided in this application, the method for sampling multiple electric drive systems according to a set operating condition includes: installing vibration sensors at the vibration location of the electric drive system, collecting vibration noise at the vibration location, and determining the sampling rate based on the noise test analysis frequency.

[0021] According to the offline testing method of the electric drive system provided in this application, the method for constructing a sample order spectrum of each electric drive system based on the sampled data includes: constructing a sample order spectrum with the horizontal axis as the speed, the vertical axis as the order, and the color scale as the vibration noise based on the rotational speed, the order, and the corresponding vibration noise in the sampled data of each electric drive system.

[0022] According to the offline testing method of the electric drive system provided in this application, the method of constructing an average order spectrum based on the order spectrum of all samples includes: calculating the average value of vibration noise corresponding to the same speed and the same order in the order spectrum of all electric drive systems, and constructing an average order spectrum with speed as the horizontal axis, order as the vertical axis, and the color scale as the average value of vibration noise.

[0023] According to the offline testing method of an electric drive system provided in this application, the method for obtaining the difference order spectrum of each electric drive system includes: calculating the difference between the vibration noise in the selected sample order spectrum and the average vibration noise value corresponding to the same rotation speed and the same order in the average order spectrum, and constructing a difference order spectrum with rotation speed as the horizontal axis, order as the vertical axis, and color scale as the difference.

[0024] According to the offline testing method for an electric drive system provided in this application, the method for analyzing the differential order spectrum of each electric drive system to determine whether the electric drive system has abnormal vibration and noise includes: statistically analyzing the maximum vibration and noise value in each speed range of the differential order spectrum, comparing the maximum vibration and noise value with a set limit value, and if the maximum vibration and noise value is greater than the set limit value, then the vibration and noise of the electric drive assembly corresponding to the differential order spectrum is determined to be unqualified; if the maximum vibration and noise value is not greater than the set limit value, then the vibration and noise of the electric drive assembly corresponding to the differential order spectrum is determined to be qualified.

[0025] This application also provides an electric drive system offline testing system, wherein the testing system operates according to any of the above-described electric drive system offline testing methods, including,

[0026] A test condition setting module, which is used to set the test conditions of the electric drive system;

[0027] The sampling module samples multiple electric drive systems according to set operating conditions.

[0028] The first data processing module constructs a sample order spectrum of each electric drive system based on the sampled data.

[0029] The second data processing module constructs an average order spectrum based on the order spectrum of all samples.

[0030] The third data processing module obtains the differential order spectrum of each electric drive system based on the sample order spectrum and the average order spectrum of each electric drive system.

[0031] The analysis module is used to analyze the difference order spectrum of each electric drive system to determine whether there is abnormal vibration and noise in the electric drive system.

[0032] According to the electric drive system offline testing system provided in this application, the first data processing module is used to construct a sample order spectrum with the horizontal axis representing the speed, the vertical axis representing the order, and the color scale representing the vibration noise based on the speed, order, and corresponding vibration noise in the sampled data of each electric drive system.

[0033] According to the electric drive system offline testing system provided in this application, the second data processing module is used to calculate the average value of vibration noise corresponding to the same speed and the same order in the sample order spectrum of all electric drive systems, and construct an average order spectrum with speed as the horizontal axis, order as the vertical axis, and color scale as the average value of vibration noise.

[0034] According to the electric drive system offline testing system provided in this application, the third data processing module is used to calculate the difference between the vibration noise in the selected sample order spectrum and the average vibration noise value corresponding to the same rotation speed and the same order in the average order spectrum, and construct a difference order spectrum with rotation speed as the horizontal axis, order as the vertical axis, and color scale as the difference.

[0035] According to the electric drive system offline testing system provided in this application, the analysis module includes,

[0036] A maximum value acquisition module is used to statistically analyze the maximum vibration noise value in each rotational speed range of the difference order spectrum.

[0037] The comparison module is used to compare the maximum value of vibration noise with a set limit value;

[0038] The judgment module determines that the vibration noise of the electric drive assembly corresponding to the difference order spectrum is unqualified when the maximum vibration noise value is greater than a set limit, and determines that the vibration noise of the electric drive assembly corresponding to the difference order spectrum is qualified when the maximum vibration noise value is not greater than the set limit.

[0039] The advantages of this application are: 1. Compared with the existing analysis methods that only utilize sample order spectrum diagrams, this application further processes the sample order spectrum diagrams. By conducting in-depth analysis of the difference order spectrum diagrams, the characteristics of local intervals are fully evaluated and analyzed, resulting in a more accurate evaluation of the vibration and noise of the entire electric drive assembly, more comprehensive control over the consistency of electric drive assembly testing, and a more precise vibration and noise testing method, which has great promotional value.

[0040] 2. The method of constructing test conditions in this application is very simple. By setting the rotational speed, torque and speed of the electric drive assembly test, the corresponding vibration noise can be easily collected, thereby forming the required sample order spectrum, which greatly facilitates the subsequent analysis.

[0041] 3. This application collects vibration noise by installing corresponding vibration sensors. The sampling rate is determined entirely based on the noise test and analysis frequency, which forms a relatively wide sampling range that can fully cover the noise test and analysis frequency, facilitating subsequent analysis and evaluation of vibration noise.

[0042] 4. The method of constructing the sample order spectrum in this application is very simple. The vibration noise is reflected by the color scale, which can more intuitively obtain the relationship between rotation speed, order and vibration noise.

[0043] 5. The average order spectrum constructed in this application is based on the order spectrum of multiple samples. It can perform overall statistical analysis on multiple electric drive assemblies in the same batch, which facilitates subsequent difference judgment on the corresponding electric drive assemblies based on the difference order spectrum and obtains the difference between each sample and the average value of other samples.

[0044] 6. The method of obtaining the difference order spectrum in this application is simple. The difference order spectrum can accurately reflect the difference between the electric drive assembly and the sampled data. The difference is reflected more intuitively, which facilitates the corresponding analysis of the electric drive assembly according to the speed range and the analysis results are more accurate.

[0045] 7. The method for judging the test results in this application is very simple. Based on the obtained difference order spectrum, the maximum vibration noise value of each speed analysis interval can be obtained. By giving the maximum vibration noise value of each speed analysis interval, the analysis curve of speed and vibration noise can be constructed. By drawing the straight line corresponding to the set limit on the analysis curve, it is possible to intuitively and quickly determine whether the vibration noise of the current electric drive assembly is qualified. The overall operation is simple and the analysis is accurate.

[0046] 8. This application also provides an electric drive system offline testing system. The testing system of this application operates according to the above testing method and can build a corresponding data processing system to facilitate the automated analysis and operation of the electric drive assembly offline testing.

[0047] The electric drive assembly offline testing method of this application analyzes the vibration and noise of the electric drive assembly through differential order spectrum diagrams, which can accurately determine whether the vibration and noise of the electric drive assembly is qualified. It fully evaluates and analyzes the characteristics of local areas, and makes the evaluation of the vibration and noise of the entire electric drive assembly more accurate. Attached Figure Description

[0048] Figure 1 The sample order spectrum of this application;

[0049] Figure 2 The average order spectrum of this application;

[0050] Figure 3 : The differential order spectra of this application;

[0051] Figure 4 : The difference order curve of this application. Detailed Implementation

[0052] The embodiments of this application are described in detail below, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0053] In the description of this application, it should be understood that the terms "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, 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 this application.

[0054] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0055] The present application will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0056] This application relates to a method for offline testing of an electric drive system. The method involves sampling and analyzing multiple electric drive assemblies of the same model. Based on the sampling data of each electric drive assembly, a sample order spectrum map corresponding to that assembly is constructed. Then, all sample order spectrum maps are combined to form an average order spectrum map of the electric drive assembly. The average order spectrum map reflects the vibration and noise conditions of all sampled samples. Each sample is then analyzed individually, and its order spectrum map is compared with the obtained average order spectrum map to examine the differences between each order spectrum map and the average order spectrum map. This yields a difference order spectrum map, which can intuitively, accurately, and clearly reflect the abnormal conditions of the current sample (i.e., the current electric drive assembly) relative to all sampled samples. Based on this abnormality, it can be determined whether the vibration and noise of the sample is acceptable, thus completing the offline testing of the electric drive assembly.

[0057] Compared to existing technologies, the testing method in this application differs significantly. Existing technologies, after sampling, directly construct sample order spectra and then evaluate and analyze based on the differences between the sample order spectra and standard order spectra. This approach analyzes the electric drive assembly from a broad perspective, neglecting the characteristics of local regions and resulting in insufficient consistency control. In contrast, this application uses the sample order spectra to generate an average order spectra, and then uses these two to generate a difference order spectra. Analysis and evaluation are then performed based on this difference order spectra. This method fully considers the characteristics of local regions, leading to more accurate vibration and noise evaluation and analysis of the electric drive assembly, and more comprehensive consistency control.

[0058] Specifically, the method for offline testing of an electric drive system according to this application is carried out according to the following steps:

[0059] S1. Set the test conditions for the electric drive system;

[0060] The purpose of setting test conditions is to construct a unified test condition. Subsequent electric drive assemblies to be tested will be tested one by one according to the set test conditions, so that the test conditions of each electric drive assembly, i.e. the sample, are the same, and the sample data collection is more accurate.

[0061] This application sets the rotational speed, torque, and speed of the rotating components of the electric drive assembly to form multiple operating conditions. The off-line testing of the electric drive assembly is mainly for testing and evaluating the vibration and noise of the electric drive assembly. The rotating components in the electric drive assembly may generate vibration and noise. Therefore, this application mainly focuses on sampling and analyzing the rotating components in the electric drive assembly. The test conditions are set based on the rotational speed, torque, and speed of the rotating components, and the electric drive assembly is then operated according to the set test conditions.

[0062] The specific test conditions are shown in Table 1:

[0063] Table 1: Reference Operating Conditions Table

[0064]

[0065] S2. Sample multiple electric drive systems according to the set operating conditions;

[0066] As mentioned above, the vibration and noise generated by the electric drive assembly in this application mainly occur in the rotating components within the electric drive assembly. Therefore, when conducting offline testing on the electric drive assembly, the main task is to install corresponding vibration sensors on the rotating components of the electric drive assembly and use the vibration sensors to collect the vibration and noise at that location.

[0067] Sampling the vibration and noise of the electric drive system also involves the sampling rate, which refers to the sampling frequency. The sampling rate of this application is determined based on the noise test and analysis frequency. The sampling rate should be able to completely cover the noise test and analysis frequency. The sampling rate of this application is more than twice the noise test and analysis frequency. The sampling rate can ensure the richness and accuracy of the data and avoid the problem of inaccurate testing caused by insufficient sampling data.

[0068] S3. Construct sample order spectral diagrams for each electric drive system based on the sampled data;

[0069] By plotting the sampled data and the corresponding working condition data as described above, a sample order spectrum is plotted. The sample order spectrum represents the relationship between the vibration noise of the sample and the corresponding test working condition.

[0070] S4. Construct an average order spectrum based on the order spectrum of all samples;

[0071] By statistically analyzing the order spectra of all samples, and then calculating based on these order spectra, we can obtain the average order spectra. The average order spectra are obtained by averaging the order spectra of all samples, and they reflect the average state of all samples.

[0072] S5. Obtain the differential order spectrum of each electric drive system based on the sample order spectrum and the average order spectrum of each electric drive system;

[0073] The difference order spectrum is an order spectrum formed by the difference between the sample order spectrum and the average order spectrum. The difference order spectrum reflects the difference between each sample and the average order spectrum.

[0074] S6. Analyze the difference order spectrum of each electric drive system to determine whether there is abnormal vibration or noise in the electric drive system.

[0075] By analyzing the differential order spectrum of each sample, it is possible to determine whether there is any abnormality in the vibration noise of the sample. The judgment method of this application mainly involves comparing the differential order spectrum with a set limit value and judging whether there is any abnormality based on the set limit value.

[0076] In some embodiments of this application, step S3 described above has been optimized, specifically, as follows: Figure 1 As shown, the method for constructing a sample order spectrum of each electric drive system based on the sampled data in this embodiment is as follows: construct a sample order spectrum with the horizontal axis representing the speed, the vertical axis representing the order, and the color scale representing the vibration noise based on the speed, order, and corresponding vibration noise in the sampled data of each electric drive system.

[0077] like Figure 1 The image shows the sample order spectrum of three electric drive systems. The sample order spectrum is a spectrum with rotational speed as the x-axis, order as the y-axis, and vibration noise as the color scale. The rotational speed is determined according to the test conditions, the order is determined according to the sampling rate, and the vibration noise is obtained by vibration sensor.

[0078] In a further embodiment of this application, step S4 described above has been optimized, specifically, as follows: Figure 2 The figure shown is the average order spectrum diagram described in this embodiment. The method for constructing the average order spectrum diagram based on the order spectrum diagrams of all samples in this embodiment is as follows: calculate the average value of vibration noise corresponding to the same speed and the same order in the order spectrum diagrams of all electric drive systems, and construct an average order spectrum diagram with the speed as the horizontal axis, the order as the vertical axis, and the color scale as the average value of vibration noise.

[0079] In essence, this involves statistically analyzing the spectral data of all the aforementioned samples. Since all sample spectral data were obtained under the same test conditions, the vibration noise at the same rotational speed and order is averaged among the sample spectral data to obtain the average value of all sample spectral data. Then, an average spectral data is constructed with rotational speed as the x-axis, order as the y-axis, and the average vibration noise value as the color scale. The average spectral data reflects the average state of all samples.

[0080] In a preferred embodiment of this application, step S5 described above has been optimized, as follows: Figure 3 As shown, this is the differential order spectrum of this embodiment. The method for obtaining the differential order spectrum of each electric drive system in this embodiment is as follows: calculate the difference between the vibration noise in the selected sample order spectrum and the average vibration noise value corresponding to the same speed and the same order in the average order spectrum, and construct a differential order spectrum with the speed as the horizontal axis, the order as the vertical axis, and the color scale as the difference.

[0081] To simplify the calculation process, this embodiment optimizes the above method by setting a rotational speed range. This embodiment divides the rotational speed into several ranges and analyzes each range separately. It only needs to calculate the maximum difference between the sample order spectrum and the average order spectrum within each rotational speed range to construct a simplified difference order spectrum. For example... Figure 4 As shown, this is a difference order curve for optimizing the difference order spectrum. The horizontal axis of this difference order curve is the order, and the vertical axis is the vibration noise. The difference order curve is formed by statistically analyzing the maximum difference in all speed ranges and then connecting the lines.

[0082] The specific calculation formula is as follows:

[0083]

[0084] y i =max(Δ ij )

[0085]

[0086] Where: Δ ij —Vibration noise values ​​corresponding to order i and rotational speed j on the differential order spectrum;

[0087] Δ i(j-1) —Vibration noise values ​​corresponding to order i and rotational speed j-1 on the differential order spectrum;

[0088] x ij —The vibration noise value corresponding to order i and rotational speed j on the sample order spectrum;

[0089] x ij '——Vibration noise values ​​corresponding to order i and rotational speed j on the average order spectrum;

[0090] σ ij —The standard deviation of the vibration noise values ​​corresponding to order i and rotational speed j on the average order spectrum;

[0091] α – Coefficient of standard deviation, typically taken as 0.2;

[0092] β – Exponential smoothing coefficient;

[0093] T – Time constant, typically taken as 2;

[0094] y i —Evaluate the maximum difference between the sample order spectrum and the average order spectrum within the speed range.

[0095] In some other embodiments of this application, step S6 above has been optimized. The method for analyzing the differential order spectrum of each electric drive system to determine whether there is abnormal vibration and noise in the electric drive system is as follows: the maximum vibration and noise value in each speed range of the differential order spectrum is statistically analyzed, and the maximum vibration and noise value is compared with a set limit. If the maximum vibration and noise value is greater than the set limit, the vibration and noise of the electric drive assembly corresponding to the differential order spectrum is determined to be unqualified; if the maximum vibration and noise value is not greater than the set limit, the vibration and noise of the electric drive assembly corresponding to the differential order spectrum is determined to be qualified.

[0096] In practice, a straight line can be drawn directly on the difference order curve based on the set limit. For example, the set limit in this embodiment is 15 dB (m / s). 2 Then, the corresponding 15 dB (m / s) can be marked on the difference order curve. 2 If the difference order curve of a sample exceeds a straight line, then the vibration and noise of the electric drive system corresponding to that sample is considered unqualified. This analysis method is very intuitive and allows for quick and easy judgment.

[0097] The offline testing method for the electric drive system in this application is as follows: Sampling and analysis are performed on the rotating components of the electric drive assembly. This primarily involves setting test conditions based on the rotational speed, torque, and rate of the rotating components, and then running the electric drive assembly according to these set test conditions. Corresponding vibration sensors are installed on the rotating components of the electric drive assembly, and vibration noise at these locations is collected using these sensors. The sampling rate is more than twice the noise test analysis frequency. Based on the rotational speed, order, and corresponding vibration noise in the sampling data of each electric drive system, a sample order spectrum is constructed with rotational speed on the horizontal axis, order on the vertical axis, and vibration noise on the color scale. The average vibration noise corresponding to the same rotational speed and order in the sample order spectrum of all electric drive systems is calculated, and an average order spectrum is constructed with rotational speed on the horizontal axis, order on the vertical axis, and the average vibration noise on the color scale. The difference between the vibration noise in the selected sample order spectrum and the average vibration noise corresponding to the same rotational speed and order in the average order spectrum is calculated, and a difference order spectrum is constructed with rotational speed on the horizontal axis, order on the vertical axis, and the difference on the color scale. The calculation is performed using the following formula:

[0098]

[0099] y i =max(Δ ij )

[0100]

[0101] Where: Δ ij—Vibration noise values ​​corresponding to order i and rotational speed j on the differential order spectrum;

[0102] Δ i(j-1) —Vibration noise values ​​corresponding to order i and rotational speed j-1 on the differential order spectrum;

[0103] x ij —The vibration noise value corresponding to order i and rotational speed j on the sample order spectrum;

[0104] x ij '——Vibration noise values ​​corresponding to order i and rotational speed j on the average order spectrum;

[0105] σ ij —The standard deviation of the vibration noise values ​​corresponding to order i and rotational speed j on the average order spectrum;

[0106] α – Coefficient of standard deviation, typically taken as 0.2;

[0107] β – Exponential smoothing coefficient;

[0108] T – Time constant, typically taken as 2;

[0109] y i —Evaluate the maximum difference between the sample order spectrum and the average order spectrum within the speed range;

[0110] Construct a difference order curve for the difference order spectrum corresponding to the sample, and analyze and judge the sample according to the set limit and the difference order curve; count the maximum vibration noise value in each speed range of the difference order curve, and compare the maximum vibration noise value with the set limit. If the maximum vibration noise value is greater than the set limit, the vibration noise of the electric drive assembly corresponding to the difference order spectrum is judged to be unqualified; if the maximum vibration noise value is not greater than the set limit, the vibration noise of the electric drive assembly corresponding to the difference order spectrum is judged to be qualified.

[0111] In addition, this application also provides an electric drive system offline testing system, including a test condition setting module, a sampling module, a first data processing module, a second data processing module, a third data processing module, and an analysis module. The test condition setting module is used to set the test conditions of the electric drive system; the sampling module samples multiple electric drive systems according to the set conditions; the first data processing module constructs a sample order spectrum map of each electric drive system based on the sampled data; the second data processing module constructs an average order spectrum map based on all sample order spectrum maps; the third data processing module obtains a differential order spectrum map of each electric drive system based on the sample order spectrum map and the average order spectrum map; the analysis module is used to analyze the differential order spectrum map of each electric drive system to determine whether the electric drive system has abnormal vibration and noise.

[0112] The first data processing module is used to construct a sample order spectrum with the horizontal axis representing the speed, the vertical axis representing the order, and the color scale representing the vibration noise, based on the speed, order, and corresponding vibration noise in the sampled data of each electric drive system.

[0113] The second data processing module is used to calculate the average vibration noise corresponding to the same rotational speed and the same order in the sample order spectrum of all electric drive systems, and to construct an average order spectrum with rotational speed on the horizontal axis, order on the vertical axis, and color scale representing the average vibration noise.

[0114] The third data processing module is used to calculate the difference between the vibration noise in the selected sample order spectrum and the average vibration noise value corresponding to the same rotation speed and the same order in the average order spectrum, and to construct a difference order spectrum with rotation speed on the horizontal axis, order on the vertical axis, and color scale as the difference.

[0115] The analysis module includes a maximum value acquisition module, a comparison module, and a judgment module. The maximum value acquisition module is used to statistically analyze the maximum vibration noise value within each speed range of the difference order spectrum. The comparison module is used to compare the maximum vibration noise value with a set limit. The judgment module determines that the vibration noise of the electric drive assembly corresponding to the difference order spectrum is unqualified when the maximum vibration noise value is greater than the set limit, and determines that the vibration noise of the electric drive assembly corresponding to the difference order spectrum is qualified when the maximum vibration noise value is not greater than the set limit.

[0116] The method described in this application was applied in practice to test an electric drive system.

[0117] The off-line operating conditions for this electric drive system are shown in Table 2.

[0118] Table 2: Operating Conditions of Electric Drive Systems After Production

[0119]

[0120] The vibration sensor measurement points for this project were determined, and its sampling rate was set to 100kHz; the standard deviation coefficient α was set to 0.2, the time constant T was set to 2, and the suspension value was set to 15.

[0121] One of the electric drive systems in this project exhibited 25.75th-order noise during acceleration at 1000-300 rpm, corresponding to the low-speed, high-torque drive condition in the off-line testing. Comparative analysis of the order spectrum of this electric drive system with that of a normal electric drive system confirmed that the 25.75th-order noise in the low-speed, high-torque drive condition of this system during off-line testing showed a slight outlier than other samples, but this outlier was not significant. The limit for this project around the 25th order noise level under this condition is 130 dB (m / s). 2Therefore, it cannot be effectively intercepted.

[0122] By comparing the order spectrum of this sample with the average order spectrum of the electric drive system, the difference order spectrum of the sample was obtained. Upon examining the difference order spectrum, a significant outlier was found at order 25.75, whose vibration noise exceeded the set limit and could therefore be effectively intercepted. Analysis of the difference order curve at order 25.75 confirmed that the main difference was in the range of 1000-3000 rpm, which was reasonably reflected in the difference order spectrum.

[0123] Compared to the comparative sample order spectrum map, which is not obvious with other sample order spectrum maps or the average order spectrum map, the difference in the difference order spectrum map can clearly reflect the differences and obtain the vibration noise situation more accurately, and its interception effect is more precise.

[0124] The foregoing has shown and described the basic principles, main features, and advantages of this application. Those skilled in the art should understand that this application is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this application. Various changes and modifications can be made to this application without departing from the spirit and scope thereof, and all such changes and modifications fall within the scope of this application as claimed. The scope of protection of this application is defined by the appended claims and their equivalents.

Claims

1. A method for offline testing of an electric drive system, characterized in that: include, Set the test conditions for the electric drive system; Samples were taken from multiple electric drive systems according to the set operating conditions; Construct sample order spectral diagrams for each electric drive system based on the sampled data; An average order spectrum is constructed based on the order spectrum of all samples. The average vibration noise corresponding to the same speed and the same order in the order spectrum of all electric drive systems is calculated. An average order spectrum is constructed with the speed on the horizontal axis, the order on the vertical axis, and the color scale representing the average vibration noise. Based on the sample order spectrum and the average order spectrum of each electric drive system, the difference order spectrum of each electric drive system is obtained. The difference between the vibration noise in the selected sample order spectrum and the average vibration noise value corresponding to the same speed and the same order in the average order spectrum is calculated. A difference order spectrum is constructed with the speed on the horizontal axis, the order on the vertical axis, and the color scale as the difference. The differential order spectrum of each electric drive system is analyzed to determine whether there is abnormal vibration and noise. The maximum vibration and noise value in each speed range of the differential order spectrum is calculated and compared with the set limit. If the maximum vibration and noise value is greater than the set limit, the vibration and noise of the electric drive assembly corresponding to the differential order spectrum is deemed unqualified; if the maximum vibration and noise value is not greater than the set limit, the vibration and noise of the electric drive assembly corresponding to the differential order spectrum is deemed qualified.

2. The method for offline testing of an electric drive system as described in claim 1, characterized in that: The method for setting the test conditions of the electric drive system includes setting the rotational speed, torque, and rate of the rotating components of the electric drive assembly to form multiple operating conditions.

3. The method for offline testing of an electric drive system as described in claim 1, characterized in that: The method for sampling multiple electric drive systems according to set operating conditions includes: installing vibration sensors at the vibration location of the electric drive system, collecting vibration noise at the vibration location, and determining the sampling rate based on the noise test analysis frequency.

4. The method for offline testing of an electric drive system as described in claim 1, characterized in that: The method for constructing a sample order spectrum of each electric drive system based on sampled data includes: constructing a sample order spectrum with the horizontal axis representing the speed, the vertical axis representing the order, and the color scale representing the vibration noise based on the rotational speed, order, and corresponding vibration noise in the sampled data of each electric drive system.

5. A system for testing the offline operation of an electric drive system, characterized in that: The testing system is operated according to any one of the electric drive system offline testing methods described in claims 1 to 4. include, A test condition setting module, which is used to set the test conditions of the electric drive system; A sampling module that samples multiple electric drive systems according to set operating conditions; The first data processing module constructs a sample order spectrum map of each electric drive system based on the sampled data. The second data processing module constructs an average order spectrum based on the order spectrum of all samples. The second data processing module is used to calculate the average value of vibration noise corresponding to the same speed and the same order in the order spectrum of all electric drive systems, and constructs an average order spectrum with speed as the horizontal axis, order as the vertical axis, and color scale as the average value of vibration noise. The third data processing module obtains the difference order spectrum of each electric drive system based on the sample order spectrum and the average order spectrum of each electric drive system. The third data processing module is used to calculate the difference between the vibration noise in the selected sample order spectrum and the average vibration noise value corresponding to the same speed and the same order in the average order spectrum, and constructs the difference order spectrum with the speed on the horizontal axis, the order on the vertical axis, and the color scale as the difference. The analysis module is used to analyze the difference order spectrum of each electric drive system to determine whether there is abnormal vibration and noise in the electric drive system. The analysis module includes, A maximum value acquisition module is used to statistically analyze the maximum vibration noise value in each rotational speed range of the difference order spectrum. The comparison module is used to compare the maximum value of vibration noise with a set limit value; The judgment module determines that the vibration noise of the electric drive assembly corresponding to the difference order spectrum is unqualified when the maximum vibration noise value is greater than a set limit, and determines that the vibration noise of the electric drive assembly corresponding to the difference order spectrum is qualified when the maximum vibration noise value is not greater than the set limit.

6. The electric drive system offline testing system as described in claim 5, characterized in that: The first data processing module is used to construct a sample order spectrum with the horizontal axis representing the speed, the vertical axis representing the order, and the color scale representing the vibration noise based on the speed, order, and corresponding vibration noise in the sampled data of each electric drive system.

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