Method for analyzing three-phase current of asynchronous drive motor for vehicle on noise performance interference

Abstract

The present application relates to a kind of vehicle asynchronous drive motor three-phase current to noise performance interference degree analysis method, including the standardization acquisition of three-phase current time domain data under multiple working conditions, time domain data segmentation pretreatment and frequency domain transformation, according to harmonic generation cause classification calculation each type of current interference coefficient, based on comprehensive interference degree coefficient completes noise interference performance rating.This method can be only with the condition of early motor and electric control prototype, by standardization three-phase current data acquisition, accurate frequency domain decomposition and systematic quantitative calculation, efficiently, accurately complete the quantitative evaluation of each type of current harmonic to motor noise performance interference degree under all working conditions, clear noise optimization core target, realize the pre-control of motor NVH performance risk, get rid of the high dependence on later vehicle level test verification, greatly shorten product development iteration cycle, reduce research and development and rectification cost.

Description

Technical Field

[0001] This invention relates to the field of asynchronous motor assemblies for new energy vehicles, and specifically to a method for analyzing the interference of three-phase current on the noise performance of an asynchronous drive motor for vehicles. Background Technology

[0002] With the rapid development of new energy vehicle technology, vehicle power performance and NVH (noise, vibration, and harshness) performance have become key indicators for measuring the core competitiveness of a vehicle and determining the user's driving experience. Currently, in order to balance the vehicle's power response, handling stability, and adaptability to all driving conditions, more and more new energy vehicles are adopting a front and rear dual-motor four-wheel drive solution; at the same time, in order to balance the vehicle's performance and development and manufacturing costs, the front drive motor often uses an asynchronous drive motor assembly.

[0003] However, in practical engineering applications, because asynchronous drive motors achieve electromechanical energy conversion based on slip, there is always a speed difference between the stator and rotor. Their electromagnetic noise sources encompass multiple factors, including fundamental magnetic field distortion, harmonic magnetic field coupling, air gap eccentricity, and rotor bar asymmetry. The noise generation and transmission mechanisms are more complex than those of permanent magnet synchronous motors, and the control difficulty is far greater. Simultaneously, the three-phase current output by the controller contains various harmonic disturbances (e.g., core odd-order harmonics caused by the inherent characteristics of carrier modulation, circulating harmonics caused by imbalances in three-phase resistance and inductance, and even-order harmonics caused by single-phase current imbalance), which further excite the motor's electromagnetic vibration and noise, directly deteriorating the NVH performance of the motor and even the entire vehicle.

[0004] In the existing technology system, the noise performance optimization of asynchronous drive motors for vehicles cannot accurately predict the degree of interference and contribution of different types of current harmonics to noise performance in advance. This makes the optimization work highly dependent on vehicle-level testing and verification in the later stages of development. This not only has industry pain points such as poor optimization targeting, long solution iteration cycle and high development cost, but also makes it impossible to effectively control the early design risks of motor NVH performance, which can easily lead to problems such as great difficulty in later rectification and delays in project development nodes.

[0005] Therefore, there is an urgent need for an analytical method for the interference of three-phase current on the noise performance of automotive asynchronous drive motors. This method should be able to efficiently and accurately quantify the interference of various current harmonics on motor noise performance under all operating conditions, given only the initial motor and electronic control prototypes. This would eliminate the heavy reliance on later vehicle-level testing and verification, significantly shorten the product development iteration cycle, and reduce R&D and rectification costs. Summary of the Invention

[0006] The purpose of this invention is to address the shortcomings of existing technologies by providing a method for analyzing the interference of three-phase current on the noise performance of automotive asynchronous drive motors. This method, with only preliminary motor and electronic control prototypes available, can efficiently and accurately quantify the interference of various current harmonics on motor noise performance under all operating conditions through standardized three-phase current data acquisition, precise frequency domain decomposition, and systematic quantitative calculation. It clarifies the core target for noise optimization, achieves pre-emptive control of motor NVH performance risks, reduces the heavy reliance on later vehicle-level testing and verification, significantly shortens the product development iteration cycle, and reduces R&D and rectification costs.

[0007] The objective of this invention is achieved through the following approach:

[0008] A method for analyzing the noise performance interference of three-phase current in an asynchronous drive motor for vehicles includes the following steps:

[0009] 1) Standardize the acquisition of three-phase current time-domain data of vehicle asynchronous drive motors under multiple operating conditions;

[0010] 2) The collected three-phase current time-domain data is segmented and preprocessed, and then frequency domain transformation is used to obtain the frequency domain characteristic data of the three-phase current under each operating condition.

[0011] 3) Classify the harmonics in the frequency domain characteristic data according to the causes of current harmonic generation, and calculate the current interference coefficients corresponding to each type of harmonic;

[0012] 4) Based on the current interference coefficients corresponding to various harmonics, obtain the comprehensive interference coefficient of the three-phase current on the motor noise performance, and complete the performance rating of the three-phase current on the noise interference based on the comprehensive interference coefficient and the preset rating system.

[0013] Preferably, in step 1), the collected operating conditions cover multiple sets of speeds and multiple sets of torque load combinations within the rated operating range of the vehicle asynchronous drive motor, and the collection time for each operating condition is not less than a preset time threshold.

[0014] Preferably, in step 2), the collected three-phase current time-domain data is preprocessed in segments, and then frequency-domain characteristic data of the three-phase current under each operating condition is obtained through frequency-domain transformation. Specific steps include:

[0015] 2-1) Set up a sliding window with an overlap rate, and use the sliding window to segment the three-phase current time domain data collected under each operating condition.

[0016] 2-2) The windowed discrete Fourier transform is used to transform each group of three-phase current time-domain data. The frequency domain characteristic data of the three-phase current under a single working condition is obtained by weighted averaging. The frequency domain characteristic data includes at least the current harmonic amplitude corresponding to each frequency point.

[0017] Preferably, in step 3), the current interference coefficients corresponding to various harmonics include:

[0018] 3-1) Three-phase current core odd-order current interference coefficient;

[0019] 3-2) Three-phase current circulation order current interference coefficient;

[0020] 3-3) Even-order current interference coefficient of three-phase current;

[0021] 3-4) Interference coefficient of three-phase current base carrier current;

[0022] 3-5) Interference coefficient of three-phase current twice that of carrier current.

[0023] Preferably, in step 3-1), the calculation steps for the odd-order current interference coefficient of the three-phase current core include:

[0024] 3-1-1) Calculate the three-phase current balance of each order in the inherent odd harmonics of carrier modulation under each operating condition using the following formula:

[0025] ;

[0026] In the formula, For the corresponding speed Torque load ratio Under operating conditions, Three-phase current balance of inherent odd harmonics in first-order carrier modulation; This represents the amplitude of the X-phase current at the inherent odd harmonic of the k-th order carrier modulation under the corresponding operating condition. This represents the amplitude of the Y-phase current at the inherent odd harmonic of the k-th order carrier modulation under the corresponding operating condition. This represents the amplitude of the Z-phase current at the inherent odd harmonic of the k-th order carrier modulation under the corresponding operating condition.

[0027] 3-1-2) Based on the three-phase current balance of the inherent odd harmonics of each order of carrier modulation under all operating conditions, and combined with the influence weight of each order of harmonics on the motor noise performance, the unbalance coefficient of the inherent odd harmonics of carrier modulation is obtained.

[0028] 3-1-3) Extract the maximum three-phase current amplitude of the inherent odd harmonics of each order carrier modulation under all operating conditions, and calculate the equivalent amplitude coefficient of the inherent odd harmonics of carrier modulation based on the weight of each order influence.

[0029] 3-1-4) Based on the obtained unbalance coefficient and equivalent amplitude coefficient, the core odd-order current interference coefficient of the three-phase current corresponding to the inherent odd harmonic of carrier modulation is obtained.

[0030] Preferably, in step 3-2), the calculation steps for the three-phase current circulating order current interference coefficient include:

[0031] 3-2-1) Determine the target order of the circulating current harmonics caused by the imbalance of three-phase resistance and inductance parameters, and extract the amplitude of each phase of the three-phase current at the target order harmonic under each operating condition;

[0032] 3-2-2) For each operating condition, calculate the amplitude of each circulating harmonic in each phase of the three-phase current under that operating condition, and the individual proportion coefficient relative to the preset reference harmonic amplitude. Sum all the individual proportion coefficients to obtain the total proportion coefficient of the circulating harmonic under that operating condition.

[0033] 3-2-3) Calculate the total proportion coefficient of circulating order harmonics under all operating conditions. Based on the statistical results of the total proportion coefficient of all operating conditions, obtain the characteristic value of circulating order harmonics under all operating conditions.

[0034] 3-2-4) Based on the full-condition characteristic value of the circulating harmonics, the three-phase current circulating order current interference coefficient corresponding to the three-phase parameter unbalanced circulating harmonics is calculated.

[0035] Preferably, in step 3-3), the calculation steps for the even-order current interference coefficient of the three-phase current include:

[0036] 3-3-1) Determine the target order of the even-order harmonics caused by single-phase current imbalance, and extract the amplitude of each phase of the three-phase current at the target order harmonic under each operating condition;

[0037] 3-3-2) For each operating condition, calculate the amplitude of each even-order harmonic in each phase of the three-phase current under that operating condition, and the individual proportion coefficient relative to the preset reference harmonic amplitude. Sum all the individual proportion coefficients to obtain the total proportion coefficient of the even-order harmonic under that operating condition.

[0038] 3-3-3) Calculate the total proportion coefficient of even-order harmonics under all operating conditions. Based on the statistical results of the total proportion coefficient of all operating conditions, obtain the characteristic value of even-order harmonics under all operating conditions.

[0039] 3-3-4) Based on the full-condition characteristic value of even-order harmonics, the three-phase current even-order current interference coefficient corresponding to the even-order harmonic of single-phase current imbalance is calculated.

[0040] Preferably, in step 3-4), the calculation steps for the interference coefficient of the three-phase current fundamental carrier current include:

[0041] 3-4-1) Determine the fundamental carrier order harmonics generated by the coupling of the carrier switching frequency and the motor rotation. The frequency of the fundamental carrier order harmonics is linked and matched with the carrier frequency of the motor controller and the number of pole pairs of the motor rotor. Extract the amplitude of each phase of the three-phase current at the fundamental carrier order harmonics under each operating condition.

[0042] 3-4-2) For each operating condition, calculate the amplitude of each phase and each fundamental carrier harmonic in the three-phase current under that operating condition, and the individual proportion coefficient relative to the preset reference harmonic amplitude. Sum all the individual proportion coefficients to obtain the total proportion coefficient of the fundamental carrier harmonic under that operating condition.

[0043] 3-4-3) Calculate the total proportion coefficient of the fundamental carrier order harmonics under all operating conditions. Based on the statistical results of the total proportion coefficient of the fundamental carrier order harmonics under all operating conditions, obtain the fundamental characteristic value of the fundamental carrier order harmonics under all operating conditions.

[0044] 3-4-4) The fundamental characteristic values ​​of the fundamental carrier order harmonics under all operating conditions are corrected by weighted adjustment of the preset weights to obtain the characteristic values ​​of the fundamental carrier order harmonics under all operating conditions.

[0045] 3-4-5) Based on the full-condition characteristic values ​​of the fundamental carrier order harmonics, the interference coefficients of the three-phase current fundamental carrier current corresponding to the carrier fundamental frequency coupling harmonics are calculated.

[0046] Preferably, in steps 3-5), the calculation steps for the interference coefficient of the three-phase current twice the carrier current include:

[0047] 3-5-1) Determine the double carrier order harmonics generated by the double carrier switching frequency and the rotational coupling of the motor. The frequency of the double carrier order harmonics is linked and matched with the double carrier frequency of the motor controller and the number of pole pairs of the motor rotor. Extract the amplitude of each phase of the three-phase current at the double carrier order harmonics under each working condition.

[0048] 3-5-2) For each operating condition, calculate the amplitude of each phase of the three-phase current with twice the carrier order harmonics under that operating condition, and the individual proportion coefficient relative to the preset reference harmonic amplitude. Sum all the individual proportion coefficients to obtain the total proportion coefficient of the twice carrier order harmonics under that operating condition.

[0049] 3-5-3) Calculate the total proportion coefficient of the second carrier order harmonics under all operating conditions. Based on the statistical results of the total proportion coefficient of the whole operating conditions, obtain the whole operating condition characteristic value of the second carrier order harmonics.

[0050] 3-5-4) Based on the full-condition characteristic value of the double carrier order harmonic, the interference coefficient of the three-phase current double carrier current corresponding to the carrier frequency coupling harmonic is calculated.

[0051] Preferably, in step 4), the steps of obtaining the comprehensive interference coefficient of the three-phase current on the motor noise performance, and completing the performance rating of the three-phase current on the noise interference based on the comprehensive interference coefficient and the preset rating system include:

[0052] 4-1) The current interference coefficients corresponding to various harmonics obtained in step 3) are superimposed and summed to obtain the comprehensive interference coefficient of the three-phase current on the motor noise performance. The specific formula is as follows:

[0053] ;

[0054] In the formula, This is the comprehensive interference coefficient of three-phase current on motor noise performance; The core odd-order current interference coefficient of the three-phase current; The order current interference coefficient of the three-phase current circulation current; The even-order current interference coefficient for three-phase current; The interference coefficient of the three-phase current base carrier current; The interference coefficient is twice that of the carrier current for the three-phase current.

[0055] 4-2) Based on the preset interference coefficient-score-level mapping table, the comprehensive interference coefficient is mapped to the corresponding performance score and performance level to complete the quantitative evaluation of the interference of the three-phase current of the vehicle asynchronous drive motor on the noise performance.

[0056] The beneficial effects of this invention are as follows:

[0057] ① This invention constructs a standardized multi-condition current data acquisition system, which comprehensively covers all combinations of operating conditions of multi-speed and multi-torque loads within the rated operating range of automotive asynchronous drive motors. Furthermore, it ensures stable data acquisition for each operating condition at a level not lower than a preset threshold. This system can completely and accurately capture the current harmonic characteristics of the motor under actual operating conditions in all scenarios. It avoids evaluation biases caused by incomplete operating condition coverage and insufficient data stability from the data source, laying a comprehensive and highly reliable data foundation for subsequent quantitative analysis of interference.

[0058] ② This invention employs a sliding window with a preset overlap rate to preprocess time-domain data in segments. After completing the frequency domain decomposition of a single set of data using a windowed discrete Fourier transform, the frequency domain feature data for a single operating condition is obtained through weighted averaging. This processing method effectively suppresses spectral leakage during the Fourier transform process and significantly reduces the impact of random interference on the accuracy of harmonic amplitude extraction. It solves the problems of insufficient accuracy in short-time data frequency domain analysis and poor robustness of single-set data, ensuring the accuracy and stability of subsequent harmonic classification and interference coefficient calculation. Simultaneously, it guarantees the consistency and reproducibility of frequency domain feature data under different operating conditions and different batches of tests, resulting in high harmonic amplitude extraction accuracy and strong repeatability of the evaluation results.

[0059] ③ This invention, based on the generation mechanism of current harmonics and the excitation path of motor electromagnetic noise, accurately classifies and decomposes the current harmonics affecting motor noise performance. For each type of harmonic, its corresponding current interference coefficient is calculated, effectively distinguishing the interference weight of different types of harmonics on motor noise and achieving complete decoupling of the contribution of harmonics from different sources to noise interference. Based on this decoupling analysis, the core harmonic source causing excessive motor electromagnetic noise can be directly located, providing a precise target for subsequent motor NVH performance optimization, significantly improving the efficiency of optimization work and the effectiveness of the solution.

[0060] ④ This invention obtains the comprehensive interference coefficient of three-phase current on noise performance through the coupled calculation of various harmonic interference coefficients. Furthermore, by establishing a standardized mapping rating system, it achieves a quantitative, comparable, and graded closed-loop evaluation of the interference degree of three-phase current on noise performance of automotive asynchronous drive motors. This method can complete a comprehensive assessment and risk classification of current harmonic interference on noise performance in the early stages of development, even with only motor and electronic control prototypes available. It completely eliminates the heavy reliance on later-stage vehicle-level testing and verification, significantly shortens the iteration cycle of motor NVH performance optimization solutions, and substantially reduces product development costs and the risk of later rectification.

[0061] ⑤ This invention eliminates the need to build a complex vehicle-level NVH testing environment. It only requires the acquisition of three-phase current data through a motor test bench to complete the entire process analysis, which greatly reduces the cost of building the testing environment and the test cycle. At the same time, by accurately identifying the core direction of noise optimization through pre-emptive evaluation, it avoids the waste of R&D resources caused by indiscriminate optimization and significantly reduces the development and rectification costs throughout the product life cycle. Attached Figure Description

[0062] Figure 1 This is a schematic diagram of the time-domain results of three-phase current acquisition under the 1000rpm-10% operating condition in an embodiment of the present invention.

[0063] Figure 2This is a schematic diagram of the frequency domain calculation results of three-phase current acquisition under the 1000rpm-10% operating condition in an embodiment of the present invention.

[0064] Figure 3 The diagram shows the amplitude results of the 5th, 7th, 11th, 13th, 17th, and 19th harmonics of the three-phase current under the 1000rpm-10% operating condition in this embodiment of the invention.

[0065] Figure 4 This is a diagram showing the amplitude results of the 3rd, 6th, and 9th harmonics of the three-phase current under the 3000rpm-25% operating condition in an embodiment of the present invention.

[0066] Figure 5 This is a diagram showing the amplitude results of the 2nd, 4th, and 8th harmonics of the three-phase current under a 5000rpm-50% operating condition in an embodiment of the present invention.

[0067] Figure 6 This is a diagram showing the amplitude results of the three-phase currents FF-3f, FF-f, FF+f, and FF+3f under the 8000rpm-75% operating condition in an embodiment of the present invention.

[0068] Figure 7 This is a diagram showing the amplitude results of the three-phase currents 2FF-6f, 2FF-2f, 2FF+2f, and 2FF+6f under 5000rpm-100% operating conditions in an embodiment of the present invention.

[0069] Figure 8 This is a flowchart of the present invention. Detailed Implementation

[0070] like Figures 1 to 8 As shown, this embodiment analyzes the interference of three-phase current on noise performance of an asynchronous drive motor for vehicles. This asynchronous drive motor adopts a 3-pole design, i.e., the number of rotor pole pairs p=3, and the carrier frequency of the matched motor controller is FF=10000Hz. The specific implementation process is carried out entirely according to the method for analyzing the interference of three-phase current on noise performance of an asynchronous drive motor for vehicles described in this invention. The detailed steps are as follows:

[0071] 1) The specific steps for standardized acquisition of three-phase current time-domain data of automotive asynchronous drive motors under multiple operating conditions include:

[0072] First, the vehicle asynchronous drive motor assembly is mechanically disconnected, that is, the motor body is disconnected from the controller and connected through a three-phase line. High-precision current clamps are installed on the X, Y, and Z phases of the three-phase line respectively for the acquisition of three-phase current data during the operation of the vehicle asynchronous drive motor assembly.

[0073] Secondly, in step 1), the collected operating conditions cover multiple sets of speeds and multiple sets of torque load combinations within the rated operating range of the vehicle asynchronous drive motor, and the collection time for each operating condition is not less than the preset time threshold.

[0074] In this embodiment, the three-phase current time-domain data acquisition covers 5 sets of speed and 5 sets of torque load ratio combinations within the rated operating range of the vehicle asynchronous drive motor, totaling 25 operating conditions. The specific operating condition settings are shown in Table 1. During the current test acquisition process for each operating condition, the acquisition time must be at least 10 seconds (i.e., at least 10 seconds of stable operating data) to avoid the impact of transient operating conditions on data accuracy. The sampling frequency of the data acquisition is set to 50,000 Hz, and the effective data volume acquired under a single operating condition is 500,000.

[0075] Table 1 Specific Operating Conditions for Current Data Acquisition

[0076]

[0077] In this embodiment, the three-phase current time-domain results acquired under the 1000rpm-10% operating condition are as follows: Figure 1 As shown.

[0078] 2) The collected three-phase current time-domain data is segmented and preprocessed, and then frequency-domain characteristic data of the three-phase current under each operating condition is obtained through frequency-domain transformation. The specific steps include:

[0079] 2-1) Set up a sliding window with an overlap rate of 50% and a window length of 25,000 data points, and use this sliding window to segment the three-phase current time-domain data collected for each operating condition; for 500,000 valid data points for a single operating condition, group them according to the following rules:

[0080] Group 1~25000 is the first group; Group 2~37500 is the second group; Group 3~50001~50000 is the third group; ...; Group 24~462500~487500 is the twenty-fourth group; Group 25~475000~500000 is the twenty-fifth group, resulting in a total of 25 overlapping segments of time-domain data. The overlap rate between groups is strictly guaranteed to be 50% to avoid spectrum leakage and data truncation errors.

[0081] 2-2) The windowed discrete Fourier transform is used to transform each group of three-phase current time-domain data. Then, the frequency domain characteristic data of the three-phase current under a single working condition is obtained by equal weight weighting. The frequency domain characteristic data includes at least the current harmonic amplitude corresponding to each frequency point.

[0082] For the 1000rpm-10% operating condition in this embodiment, Fourier decomposition calculations were performed on each data set according to the following formula:

[0083] ;

[0084] ;

[0085] ;

[0086] In the formula, This is the frequency domain decomposition result of the first group of x-phase current data under the operating condition of 1000 rpm and 10% torque load. This is the frequency domain decomposition result of the first group of y-phase current data under the operating condition of 1000 rpm and 10% torque load. This is the frequency domain decomposition result of the first group of z-phase current data under the operating condition of 1000 rpm and 10% torque load. For frequency; This is the m-th data point in the first group of data for the x-direction current; This is the m-th data point in the first group of data for the y-direction current. This is the m-th data point in the first group of data for the z-direction current. The data point number in the first group of data; Pi is a constant.

[0087] Using the same method described above, and calculating the frequency domain decomposition results for groups 2 to 25 under this operating condition. , , ,....., , , .

[0088] Then, using the following equally weighted average formula, obtain the final frequency domain calculation result for this operating condition:

[0089] ;

[0090] ;

[0091] ;

[0092] In the formula, The frequency domain calculation results are for the x-phase current under the operating conditions of 1000 rpm and 10% torque load. The frequency domain calculation results of the y-phase current under the operating conditions of 1000 rpm and 10% torque load are given. The frequency domain calculation results of the z-phase current under the operating conditions of 1000 rpm and 10% torque load are given. This is the nth set of data under this operating condition; This is the frequency domain decomposition result of the nth group of x-phase current data under the operating condition of 1000 rpm and 10% torque load. This is the frequency domain decomposition result of the nth group of y-phase current data under the operating condition of 1000 rpm and 10% torque load. This is the frequency domain decomposition result of the nth group of z-phase current data under the operating condition of 1000 rpm and 10% torque load.

[0093] Following the same method described above, frequency domain characteristic data of the X, Y, and Z three-phase currents under another 24 operating conditions were calculated. In this embodiment, the frequency domain calculation results of the three-phase current under the 1000rpm-10% operating condition are shown below. Figure 2 .

[0094] 3) Classify the harmonics in the frequency domain characteristic data according to the causes of current harmonic generation, and calculate the current interference coefficients corresponding to each type of harmonic.

[0095] Based on their causes, current harmonics are classified into five categories: carrier modulation inherent odd-order harmonics, three-phase parameter imbalance circulating current harmonics, single-phase current imbalance even-order harmonics, carrier fundamental frequency coupling harmonics, and carrier frequency doubling coupling harmonics. The corresponding calculated current interference coefficients for each category are: three-phase current core odd-order current interference coefficient, three-phase current circulating current interference coefficient, three-phase current even-order current interference coefficient, three-phase current fundamental carrier current interference coefficient, and three-phase current double carrier current interference coefficient. The specific calculation process for each interference coefficient is as follows:

[0096] 3-1) Calculation of the core odd-order current interference coefficient of three-phase current, the specific steps include:

[0097] 3-1-1) The target orders of the inherent odd harmonics of the carrier modulation are determined to be the 5th, 7th, 11th, 13th, 17th, and 19th orders. This is because, experimental verification shows that the currents of these six orders are inherent characteristics of the carrier modulation and cannot be completely eliminated. The three-phase AC balance of each target order under each operating condition is calculated using the following formula:

[0098] ;

[0099] In the formula, For the corresponding speed Torque load ratio Under operating conditions, Three-phase current balance of inherent odd harmonics in first-order carrier modulation; This represents the amplitude of the X-phase current at the inherent odd harmonic of the k-th order carrier modulation under the corresponding operating condition. This represents the amplitude of the Y-phase current at the inherent odd harmonic of the k-th order carrier modulation under the corresponding operating condition. This represents the amplitude of the Z-phase current at the inherent odd harmonic of the k-th order carrier modulation under the corresponding operating conditions.

[0100] The frequencies of the harmonics of each target order are linked to the electrical frequency of the motor. The harmonic amplitudes corresponding to the above six target orders are as follows:

[0101] ,

[0102] ,

[0103] ,

[0104] ,

[0105] ,

[0106] ,

[0107] ,

[0108] .

[0109] in, This indicates the rotational speed under the corresponding operating condition; This indicates the percentage of torque load under the corresponding operating condition; * indicates the number of rotor pole pairs of the motor; *5 indicates the 5th order current; *7 indicates the 7th order current; *11 indicates the 11th order current; *13 indicates the 13th order current; *17 indicates the 17th order current; *19 indicates the 19th order current.

[0110] In this embodiment, the amplitude results of the 5th, 7th, 11th, 13th, 17th, and 19th harmonics of the three-phase current under the 1000rpm-10% operating condition are as follows: Figure 3 As shown.

[0111] For each order of harmonics, the three-phase current balance under all operating conditions is calculated using the following formulas:

[0112] ;

[0113] ;

[0114] ;

[0115] ;

[0116] ;

[0117] ;

[0118] In the formula, The 5th order current harmonic balance under operating conditions of rpm speed and Tor% torque load ratio; The 7th order current harmonic balance under operating conditions of rpm speed and Tor% torque load ratio; The 11th-order current harmonic balance under operating conditions of rpm speed and Tor% torque load ratio; The 13th order current harmonic balance under operating conditions of rpm speed and Tor% torque load ratio; The 17th order current harmonic balance under operating conditions of rpm speed and Tor% torque load ratio; The balance of the 19th order current harmonics under the conditions of rpm speed and Tor% torque load ratio.

[0119] 3-1-2) Based on the three-phase current balance of the inherent odd harmonics of each order of carrier modulation under all operating conditions, and combined with the influence weight of each order of harmonics on the motor noise performance, the imbalance coefficient of the inherent odd harmonics of carrier modulation is obtained. The calculation formula is as follows:

[0120] ;

[0121] In the formula, The core odd-order unbalance coefficient of the three-phase current; The average value of the fifth-order current harmonic amplitude calculated for all operating conditions; The average value of the 7th order current harmonic amplitude calculated for all operating conditions; The average value of the 11th-order current harmonic amplitude calculated for all operating conditions; The average value of the 13th order current harmonic amplitude calculated for all operating conditions; The average value of the 17th order current harmonic amplitude calculated for all operating conditions; This is the average value of the 19th order current harmonic amplitude calculated for all operating conditions.

[0122] In this embodiment, the average value of the core odd-order harmonic amplitude of the three-phase current under all operating conditions is shown in Table 2 below. The unbalance coefficient calculated based on the above formula is: .

[0123] Table 2. Average value of the core odd-order harmonic balance of three-phase current under all operating conditions.

[0124]

[0125] 3-1-3) Extract the maximum three-phase current amplitude of the inherent odd harmonics of each order of carrier modulation under all operating conditions, and calculate the equivalent amplitude coefficient of the inherent odd harmonics of carrier modulation based on the weighted average of each order's influence. The calculation formula is:

[0126] ;

[0127] In the formula, For the corresponding torque load ratio operating conditions, at all speeds The maximum value of the third harmonic three-phase current amplitude .

[0128] In this embodiment, the equivalent amplitude coefficient is calculated based on full-condition data. .

[0129] 3-1-4) Based on the obtained imbalance coefficient and equivalent amplitude coefficient, the core odd-order current interference coefficient of the three-phase current corresponding to the inherent odd-order harmonics of carrier modulation is obtained. The calculation formula is:

[0130]

[0131] In the formula, The core odd-order current interference coefficient of the three-phase current; The core odd-order unbalance coefficient of the three-phase current; It is the equivalent amplitude coefficient of the inherent odd harmonics of carrier modulation.

[0132] In this embodiment, the core odd-order current interference coefficient of the three-phase current is calculated based on the above formula. .

[0133] 3-2) Calculation of the order current interference coefficient of the three-phase current circulation, the specific steps include:

[0134] 3-2-1) The target orders of the circulating current harmonics caused by the imbalance of three-phase resistance and inductance parameters are determined to be the 3rd, 6th, and 9th orders. The amplitudes of each phase of the three-phase current at the target order harmonics are extracted under each operating condition. The amplitudes of these three corresponding orders are as follows:

[0135] ,

[0136] ,

[0137] ,

[0138] ,

[0139] .

[0140] In the formula, This indicates the rotational speed under the corresponding operating condition; This indicates the percentage of torque load under the corresponding operating condition; Indicates the number of poles of the rotor. *3 indicates the 3rd order current; *6 indicates the 6th order current; *9 indicates the 9th order current.

[0141] In this embodiment, the amplitude results of the 3rd, 6th, and 9th harmonics of the three-phase current under the 3000rpm-25% operating condition are as follows: Figure 4 As shown.

[0142] 3-2-2) For each operating condition, calculate the amplitude of each circulating harmonic of each phase in the three-phase current under that condition, and the individual proportion coefficient relative to the preset reference harmonic amplitude (5th order harmonic amplitude). Sum all the individual proportion coefficients to obtain the total proportion coefficient of the circulating harmonics under that operating condition. The calculation formula is:

[0143] ;

[0144] In the formula, It is the coefficient of the circulating harmonic amplitude under the operating conditions of speed of rpm and torque load ratio of Tor%.

[0145] 3-2-3) Calculate the total proportion coefficient of circulating order harmonics under all operating conditions. Based on the statistical results of the total proportion coefficient of all operating conditions, obtain the characteristic value of circulating order harmonics under all operating conditions.

[0146] 3-2-4) Based on the full-condition characteristic values ​​of the circulating current order harmonics, the three-phase current circulating current order current interference coefficients corresponding to the three-phase parametric unbalanced circulating current harmonics are calculated. The calculation formula is:

[0147] ;

[0148] In the formula, The order current interference coefficient of the three-phase current circulation current; This represents the average value of the circulating harmonic amplitude ratio under all operating conditions.

[0149] In this embodiment, the three-phase current circulation order current interference coefficient is calculated based on full-condition data. .

[0150] 3-3) Calculation of the even-order current interference coefficient of three-phase current, the specific steps include:

[0151] 3-3-1) The target orders of the even-order harmonics caused by single-phase current imbalance are determined to be the 2nd, 4th, and 8th orders. The amplitudes of each phase of the three-phase current at the target order harmonics are extracted under each operating condition. The amplitudes of these three corresponding orders are as follows:

[0152] ,

[0153] ,

[0154] ,

[0155] ,

[0156] .

[0157] In the formula, This indicates the rotational speed under the corresponding operating condition; This indicates the percentage of torque load under the corresponding operating condition; Indicates the number of poles of the rotor. *2 indicates the second-order current; *4 indicates the fourth-order current; *8 indicates the eighth-order current.

[0158] In this embodiment, the amplitude results of the 2nd, 4th, and 8th harmonics of the three-phase current under the 5000rpm-50% operating condition are as follows: Figure 5 As shown.

[0159] 3-3-2) For each operating condition, calculate the amplitude of each even-order harmonic in each phase of the three-phase current under that condition, and the individual proportion coefficient relative to the preset reference harmonic amplitude (5th order harmonic amplitude). Sum all the individual proportion coefficients to obtain the total proportion coefficient of the even-order harmonics under that operating condition. The calculation formula is:

[0160] ;

[0161] In the formula, The rotational speed is expressed in rpm; the torque load percentage is... The percentage of even-order current amplitude under certain operating conditions.

[0162] 3-3-3) Calculate the total proportion coefficient of even-order harmonics under all operating conditions. Based on the statistical results of the total proportion coefficient of all operating conditions, obtain the characteristic value of even-order harmonics under all operating conditions.

[0163] 3-3-4) Based on the full-condition characteristic values ​​of even-order harmonics, the even-order current interference coefficients of the three-phase current corresponding to the even-order harmonics of single-phase current imbalance are calculated. The calculation formula is:

[0164] ;

[0165] In the formula, The even-order current interference coefficient for three-phase current; The average value of the even-order current interference coefficient of the three-phase current under all operating conditions.

[0166] In this embodiment, the even-order current interference coefficient of the three-phase current is calculated based on full-condition data. .

[0167] 3-4) Calculation of the interference coefficient of the three-phase current fundamental carrier current, the specific steps include:

[0168] 3-4-1) The fundamental carrier order harmonics generated by the coupling between the carrier switching frequency and the motor rotation are determined to be FF-3p; FF-1p; FF+1p; FF+3p. Where FF is the motor controller carrier frequency. The frequency of the fundamental carrier order harmonics is linked and matched with the motor controller carrier frequency and the number of motor rotor pole pairs. The amplitude of each phase of the three-phase current at the fundamental carrier order harmonic is extracted under each operating condition, specifically:

[0169] ,

[0170] ,

[0171] ,

[0172] ,

[0173] ,

[0174] .

[0175] in, This indicates the rotational speed under the corresponding operating condition; % indicates the percentage of torque load in the corresponding operating condition; Indicates the number of poles of the rotor. This indicates the FF-3p current harmonic, and so on.

[0176] In this embodiment, the amplitude results of the three-phase currents FF-3f, FF-f, FF+f, and FF+3f harmonics under the motor controller carrier frequency FF=10000Hz and the 8000rpm-75% operating condition are as follows: Figure 6 As shown.

[0177] 3-4-2) For each operating condition, calculate the amplitude of each fundamental carrier harmonic in each phase of the three-phase current under that condition, and the individual proportion coefficient relative to the preset reference harmonic amplitude (5th order harmonic amplitude). Sum all individual proportion coefficients to obtain the total proportion coefficient of the fundamental carrier harmonic under that operating condition. The calculation formula is:

[0178] ;

[0179] In the formula, The rotational speed is expressed in rpm; the torque load percentage is... The ratio of the order amplitude of the three-phase current base carrier current under operating conditions.

[0180] 3-4-3) Calculate the total proportion coefficient of the fundamental carrier order harmonics under all operating conditions. Based on the statistical results of the total proportion coefficient of the fundamental carrier order harmonics under all operating conditions, obtain the fundamental characteristic value of the fundamental carrier order harmonics under all operating conditions.

[0181] 3-4-4) The fundamental characteristic values ​​of the fundamental carrier order harmonics under all operating conditions are corrected by a preset weight to obtain the characteristic values ​​of the fundamental carrier order harmonics under all operating conditions; in this embodiment, the preset weight is set to 0.05.

[0182] 3-4-5) Based on the full-condition characteristic values ​​of the fundamental carrier order harmonics, the interference coefficients of the three-phase fundamental carrier current corresponding to the carrier fundamental frequency coupling harmonics are calculated. The calculation formula is:

[0183] ;

[0184] In the formula, The interference coefficient of the three-phase current base carrier current; This represents the average value of the order amplitude ratio of the three-phase flow base carrier current under all operating conditions.

[0185] In this embodiment, the interference coefficient of the three-phase current base carrier current is calculated based on full-condition data. .

[0186] 3-5) Calculation of the interference coefficient of three-phase current twice the carrier current, the specific steps include:

[0187] 3-5-1) The double carrier order harmonics generated by the coupling between the double carrier switching frequency and the motor rotation are determined to be 2FF-6p; 2FF-2p; 2FF+2p; 2FF+6p, where FF represents the carrier frequency. The frequency of the double carrier order harmonics is linked and matched with the double carrier frequency of the motor controller and the number of pole pairs of the motor rotor. The amplitude of each phase of the three-phase current at the double carrier order harmonic is extracted under each operating condition. The corresponding amplitudes are as follows:

[0188] ,

[0189] ,

[0190] ,

[0191] ,

[0192] ,

[0193] .

[0194] In the formula, This indicates the rotational speed under the corresponding operating condition; This indicates the percentage of torque load under the corresponding operating condition; Indicates the number of poles of the rotor. 2 This represents the 2FF-6p order current harmonics, and so on.

[0195] In this embodiment, the amplitude results of the three-phase current 2FF-6f, 2FF-2f, 2FF+2f, and 2FF+6f harmonics under the 5000rpm-100% operating condition are as follows: Figure 7 As shown.

[0196] 3-5-2) For each operating condition, calculate the amplitude of the twice-carrier-order harmonic in each phase of the three-phase current under that condition, and the individual proportion coefficient relative to the preset reference harmonic amplitude (5th-order harmonic amplitude). Sum all the individual proportion coefficients to obtain the total proportion coefficient of the twice-carrier-order harmonic under that operating condition. The calculation formula is:

[0197] ;

[0198] In the formula: The rotational speed is expressed in rpm, and the torque load ratio is expressed in rpm. The ratio of the amplitude of the three-phase current to the second carrier current under operating conditions.

[0199] 3-5-3) Calculate the total proportion coefficient of the second carrier order harmonics under all operating conditions. Based on the statistical results of the total proportion coefficient of the whole operating conditions, obtain the whole operating condition characteristic value of the second carrier order harmonics.

[0200] 3-5-4) Based on the full-condition characteristic value of the second carrier order harmonic, the interference coefficient of the three-phase current corresponding to the carrier frequency coupling harmonic is calculated. .

[0201] ;

[0202] In the formula, The interference coefficient is twice that of the carrier current for the three-phase current. The average value of the three-phase current twice the carrier current order amplitude ratio under all operating conditions.

[0203] In this embodiment, the interference coefficient of the three-phase current twice the carrier current is calculated based on full-condition data. .

[0204] 4) Based on the current interference coefficients corresponding to various harmonics, obtain the comprehensive interference coefficient of the three-phase current on the motor noise performance. Then, based on this comprehensive interference coefficient and the preset rating system, complete the performance rating of the three-phase current on the noise interference, as detailed below:

[0205] 4-1) The current interference coefficients corresponding to various harmonics obtained in step 3) are superimposed and summed to obtain the comprehensive interference coefficient of the three-phase current on the motor noise performance. The specific formula is as follows:

[0206] ;

[0207] In the formula, This is the comprehensive interference coefficient of three-phase current on motor noise performance; The core odd-order current interference coefficient of the three-phase current; The order current interference coefficient of the three-phase current circulation current; The even-order current interference coefficient for three-phase current; The interference coefficient of the three-phase current base carrier current; The interference coefficient is twice that of the carrier current for the three-phase current.

[0208] In this embodiment, the overall interference coefficient is calculated by substituting each interference coefficient into the formula:

[0209]

[0210] 4-2) Based on the preset interference coefficient-score-level mapping table, the comprehensive interference coefficient is mapped to the corresponding performance score and performance level, thus completing the quantitative evaluation of the interference of the three-phase current of the vehicle asynchronous drive motor on noise performance. The mapping table is shown in Table 3 below:

[0211] Table 3. Scoring and Rating of Three-Phase Current Noise Performance Interference Level

[0212]

[0213] In this embodiment, the comprehensive interference coefficient is 2.10, which falls within the coefficient range of 1.8 to 2.2, corresponding to a performance score of 7 points and a performance level of good. This completes the quantitative analysis and rating of the interference of the three-phase current of the vehicle asynchronous drive motor on the noise performance.

[0214] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications made to the present invention by those skilled in the art without departing from the spirit of the present invention shall fall within the protection scope of the present invention.

Claims

1. A method for analyzing the interference of three-phase current on the noise performance of an asynchronous drive motor for vehicles, characterized in that, Includes the following steps: 1) Standardize the acquisition of three-phase current time-domain data of vehicle asynchronous drive motors under multiple operating conditions; 2) The collected three-phase current time-domain data is segmented and preprocessed, and then frequency domain transformation is used to obtain the frequency domain characteristic data of the three-phase current under each operating condition. 3) Classify the harmonics in the frequency domain characteristic data according to the causes of current harmonic generation, and calculate the current interference coefficients corresponding to each type of harmonic; 4) Based on the current interference coefficients corresponding to various harmonics, obtain the comprehensive interference coefficient of the three-phase current on the motor noise performance, and complete the performance rating of the three-phase current on the noise interference based on the comprehensive interference coefficient and the preset rating system.

2. The analytical method according to claim 1, characterized in that, In step 1), the collected operating conditions cover multiple sets of speeds and multiple sets of torque load combinations within the rated operating range of the vehicle asynchronous drive motor, and the collection time for each operating condition is not less than the preset time threshold.

3. The analytical method according to claim 1, characterized in that, In step 2), the collected three-phase current time-domain data is preprocessed in segments, and then frequency-domain characteristic data of the three-phase current under each operating condition is obtained through frequency-domain transformation. The specific steps include: 2-1) Set up a sliding window with an overlap rate, and use the sliding window to segment the three-phase current time domain data collected under each operating condition. 2-2) The windowed discrete Fourier transform is used to transform each group of three-phase current time-domain data. The frequency domain characteristic data of the three-phase current under a single working condition is obtained by weighted averaging. The frequency domain characteristic data includes at least the current harmonic amplitude corresponding to each frequency point.

4. The analytical method according to claim 1, characterized in that, In step 3), the current interference coefficients corresponding to various harmonics include: 3-1) Three-phase current core odd-order current interference coefficient; 3-2) Three-phase current circulation order current interference coefficient; 3-3) Even-order current interference coefficient of three-phase current; 3-4) Interference coefficient of three-phase current base carrier current; 3-5) Interference coefficient of three-phase current twice that of carrier current.

5. The analytical method according to claim 4, characterized in that, In step 3-1), the calculation steps for the odd-order current interference coefficient of the three-phase current core include: 3-1-1) Calculate the three-phase current balance of each order in the inherent odd harmonics of carrier modulation under each operating condition using the following formula: ； In the formula, For the corresponding speed Torque load ratio Under operating conditions, Three-phase current balance of inherent odd harmonics in order carrier modulation; This represents the amplitude of the X-phase current at the inherent odd harmonic of the k-th order carrier modulation under the corresponding operating condition. This represents the amplitude of the Y-phase current at the inherent odd harmonic of the k-th order carrier modulation under the corresponding operating condition. This represents the amplitude of the Z-phase current at the inherent odd harmonic of the k-th order carrier modulation under the corresponding operating condition. 3-1-2) Based on the three-phase current balance of the inherent odd harmonics of each order of carrier modulation under all operating conditions, and combined with the influence weight of each order of harmonics on the motor noise performance, the unbalance coefficient of the inherent odd harmonics of carrier modulation is obtained. 3-1-3) Extract the maximum three-phase current amplitude of the inherent odd harmonics of each order carrier modulation under all operating conditions, and calculate the equivalent amplitude coefficient of the inherent odd harmonics of carrier modulation based on the weight of each order influence. 3-1-4) Based on the obtained unbalance coefficient and equivalent amplitude coefficient, the core odd-order current interference coefficient of the three-phase current corresponding to the inherent odd harmonic of carrier modulation is obtained.

6. The analytical method according to claim 4, characterized in that, In step 3-2), the calculation steps for the three-phase current circulating order current interference coefficient include: 3-2-1) Determine the target order of the circulating current harmonics caused by the imbalance of three-phase resistance and inductance parameters, and extract the amplitude of each phase of the three-phase current at the target order harmonic under each operating condition; 3-2-2) For each operating condition, calculate the amplitude of each circulating harmonic in each phase of the three-phase current under that operating condition, and the individual proportion coefficient relative to the preset reference harmonic amplitude. Sum all the individual proportion coefficients to obtain the total proportion coefficient of the circulating harmonic under that operating condition. 3-2-3) Calculate the total proportion coefficient of circulating order harmonics under all operating conditions. Based on the statistical results of the total proportion coefficient of all operating conditions, obtain the characteristic value of circulating order harmonics under all operating conditions. 3-2-4) Based on the full-condition characteristic value of the circulating harmonics, the three-phase current circulating order current interference coefficient corresponding to the three-phase parameter unbalanced circulating harmonics is calculated.

7. The analytical method according to claim 4, characterized in that, In step 3-3), the calculation steps for the even-order current interference coefficient of the three-phase current include: 3-3-1) Determine the target order of the even-order harmonics caused by single-phase current imbalance, and extract the amplitude of each phase of the three-phase current at the target order harmonic under each operating condition; 3-3-2) For each operating condition, calculate the amplitude of each even-order harmonic in each phase of the three-phase current under that operating condition, and the individual proportion coefficient relative to the preset reference harmonic amplitude. Sum all the individual proportion coefficients to obtain the total proportion coefficient of the even-order harmonic under that operating condition. 3-3-3) Calculate the total proportion coefficient of even-order harmonics under all operating conditions. Based on the statistical results of the total proportion coefficient of all operating conditions, obtain the characteristic value of even-order harmonics under all operating conditions. 3-3-4) Based on the full-condition characteristic value of even-order harmonics, the three-phase current even-order current interference coefficient corresponding to the even-order harmonic of single-phase current imbalance is calculated.

8. The analytical method according to claim 4, characterized in that, In steps 3-4), the calculation steps for the interference coefficient of the three-phase current fundamental carrier current include: 3-4-1) Determine the fundamental carrier order harmonics generated by the coupling of the carrier switching frequency and the motor rotation. The frequency of the fundamental carrier order harmonics is linked and matched with the carrier frequency of the motor controller and the number of pole pairs of the motor rotor. Extract the amplitude of each phase of the three-phase current at the fundamental carrier order harmonics under each operating condition. 3-4-2) For each operating condition, calculate the amplitude of each phase and each fundamental carrier harmonic in the three-phase current under that operating condition, and the individual proportion coefficient relative to the preset reference harmonic amplitude. Sum all the individual proportion coefficients to obtain the total proportion coefficient of the fundamental carrier harmonic under that operating condition. 3-4-3) Calculate the total proportion coefficient of the fundamental carrier order harmonics under all operating conditions. Based on the statistical results of the total proportion coefficient of the fundamental carrier order harmonics under all operating conditions, obtain the fundamental characteristic value of the fundamental carrier order harmonics under all operating conditions. 3-4-4) The fundamental characteristic values ​​of the fundamental carrier order harmonics under all operating conditions are corrected by weighted adjustment of the preset weights to obtain the characteristic values ​​of the fundamental carrier order harmonics under all operating conditions. 3-4-5) Based on the full-condition characteristic values ​​of the fundamental carrier order harmonics, the interference coefficients of the three-phase current fundamental carrier current corresponding to the carrier fundamental frequency coupling harmonics are calculated.

9. The analytical method according to claim 4, characterized in that, In steps 3-5), the calculation steps for the interference coefficient of the three-phase current twice the carrier current include: 3-5-1) Determine the double carrier order harmonics generated by the double carrier switching frequency and the rotational coupling of the motor. The frequency of the double carrier order harmonics is linked and matched with the double carrier frequency of the motor controller and the number of pole pairs of the motor rotor. Extract the amplitude of each phase of the three-phase current at the double carrier order harmonics under each working condition. 3-5-2) For each operating condition, calculate the amplitude of each phase of the three-phase current with twice the carrier order harmonics under that operating condition, and the individual proportion coefficient relative to the preset reference harmonic amplitude. Sum all the individual proportion coefficients to obtain the total proportion coefficient of the twice carrier order harmonics under that operating condition. 3-5-3) Calculate the total proportion coefficient of the second carrier order harmonics under all operating conditions. Based on the statistical results of the total proportion coefficient of the whole operating conditions, obtain the whole operating condition characteristic value of the second carrier order harmonics. 3-5-4) Based on the full-condition characteristic value of the double carrier order harmonic, the interference coefficient of the three-phase current double carrier current corresponding to the carrier frequency coupling harmonic is calculated.

10. The analytical method according to claim 1, characterized in that, In step 4), the comprehensive interference coefficient of the three-phase current on the motor noise performance is obtained, and the performance rating of the three-phase current on the noise interference is completed based on this comprehensive interference coefficient and the preset rating system. The steps include: 4-1) The current interference coefficients corresponding to various harmonics obtained in step 3) are superimposed and summed to obtain the comprehensive interference coefficient of the three-phase current on the motor noise performance. The specific formula is as follows: ； In the formula, This is the comprehensive interference coefficient of three-phase current on motor noise performance; The core odd-order current interference coefficient of the three-phase current; The order current interference coefficient of the three-phase current circulation current; The even-order current interference coefficient for three-phase current; The interference coefficient of the three-phase current base carrier current; The interference coefficient is twice that of the carrier current for the three-phase current. 4-2) Based on the preset interference coefficient-score-level mapping table, the comprehensive interference coefficient is mapped to the corresponding performance score and performance level to complete the quantitative evaluation of the interference of the three-phase current of the vehicle asynchronous drive motor on the noise performance.

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