Vehicle permanent magnet synchronous motor vibration transmission capability analysis method

Abstract

The invention discloses a vehicle permanent magnet synchronous motor vibration transmission capability analysis method, which establishes a simulation calculation model of a permanent magnet synchronous motor, and specifically comprises the following steps: step 1) calculating a cogging torque peak-to-peak value of the permanent magnet synchronous motor; step 2) calculating a counter electromotive force harmonic amplitude ratio of the permanent magnet synchronous motor; 3) calculating the time domain electromagnetic force of the permanent magnet synchronous motor; 4) calculating the tangential force density of the permanent magnet synchronous motor; 5) calculating the radial force density of the permanent magnet synchronous motor; 6) extracting stator structure parameters of the permanent magnet synchronous motor; and 7) analyzing the vibration transmission capability of the permanent magnet synchronous motor. According to the method, under the condition that high-frequency electromagnetic noise simulation is not carried out, rapid evaluation of the electromagnetic noise suppression capability of a motor design scheme can be realized, so that the development period is shortened, and the cost is saved.

Description

Technical Field

[0001] The present invention relates to the technical field of motors, and particularly relates to a method for analyzing the vibration transfer ability of a permanent magnet synchronous motor for vehicles. Background Art

[0002] A battery electric vehicle (BEV) is a vehicle that completely relies on the electrical energy stored in a battery to drive an electric motor. The energy of a battery electric vehicle comes from an on-vehicle battery pack, usually a lithium-ion battery pack. The battery pack stores electrical energy and provides power for the electric motor. Since a battery electric vehicle does not use an internal combustion engine, no exhaust gas is emitted during driving, which is friendly to the environment and helps reduce air pollution and greenhouse gas emissions.

[0003] Since a battery electric vehicle eliminates the engine unit and replaces it with an electric drive unit, without the noise masking caused by engine combustion and torque output, the high-frequency electromagnetic noise of the electric drive unit becomes prominent. In the battery electric vehicle market, the high-frequency electromagnetic noise generated by the electric motor in the electric drive unit has become a key concern.

[0004] In the early stage of motor design and development, without the intervention of prototypes and tests, the high-frequency electromagnetic noise generated by the motor can only be analyzed through multi-physics field coupling simulation, which requires a large amount of computing resources and time cycles and cannot meet the development progress requirements of the whole vehicle. Summary of the Invention

[0005] Aiming at the above deficiencies of the prior art, the technical problem to be solved by the present invention is: how to provide a method for analyzing the vibration transfer ability of a permanent magnet synchronous motor for vehicles and its processing method, which can quickly evaluate the ability of a motor design scheme to suppress electromagnetic noise without high-frequency electromagnetic noise simulation, so as to shorten the development cycle and save costs.

[0006] To solve the above technical problem, the present invention adopts the following technical solutions:

[0007] A method for analyzing the vibration transfer ability of a permanent magnet synchronous motor for vehicles, which establishes a simulation calculation model of the permanent magnet synchronous motor, specifically including the following steps:

[0008] Step 1) Calculate the peak-to-peak value of the cogging torque of the permanent magnet synchronous motor;

[0009] Step 2) Calculate the proportion of the harmonic amplitude of the back electromotive force of the permanent magnet synchronous motor;

[0010] Step 3) Calculate the time-domain electromagnetic force of the permanent magnet synchronous motor;

[0011] Step 4) Calculate the tangential force density of the permanent magnet synchronous motor;

[0012] Step 5) Calculate the radial force density of the permanent magnet synchronous motor;

[0013] Step 6) Extract the stator structure parameters of the permanent magnet synchronous motor;

[0014] Step 7) Conduct an analysis on the vibration transfer ability of the permanent magnet synchronous motor.

[0015] Preferably, in Step 1), the calculation method for the peak-to-peak value of the cogging torque of the permanent magnet synchronous motor is as follows: Set the control current in the permanent magnet synchronous motor simulation calculation model to 0, set the rotor speed to n, and set the rotor to perform a calculation once every n 1 °. Record the torque generated by the rotor at this time, calculate M times in total, record M torque values, and have n 1 ° * M = 360°, so that the equivalent space rotation of the rotor is 360°, and calculate the peak-to-peak value of the cogging torque of this permanent magnet synchronous motor according to the following formula:

[0016] CT = MAX(coqt(θ 1 ), coqt(θ 2 ),... coqt(θ M )) / MIN(coqt(θ 1 θ, coqt(θ 2 ),... coqt(θ M ))

[0017] In the formula: CT is the peak-to-peak value of the cogging torque of the permanent magnet synchronous motor for heating;

[0018] MAX() is the maximum value among all data;

[0019] MIN() is the minimum value among all data;

[0020] coqt(θ i ) is the torque generated by the rotor calculated at the i-th angle, i = 1, 2, 3... M.

[0021] Preferably, in Step 2), the calculation method for the proportion of the harmonic amplitude of the back electromotive force of the permanent magnet synchronous motor is as follows: Set the control current in the permanent magnet synchronous motor simulation calculation model to 0, set the rotor speed to n; set the rotor to perform a calculation once every n 1 °. Record the transient magnetic flux value generated by the rotor at this time, calculate M times in total, record M transient magnetic flux values, and have n 1 ° * M = 360°, so that the equivalent space rotation of the rotor is 360°, and then calculate the transient back electromotive force of the permanent magnet synchronous motor according to the following formula:

[0022] e c (θ i ) = 2πNΦ i k / f

[0023] where: e c (θ i ) is the transient back electromotive force calculated at the i-th angle;

[0024] N is the number of turns of the stator winding;

[0025] φ i is the transient magnetic flux value calculated at the i-th angle;

[0026] k is the air-gap waveform coefficient;

[0027] f is the power supply frequency;

[0028] After the calculation is completed, the M calculated transient back electromotive forces are subjected to discrete Fourier transform according to the following formula:

[0029]

[0030] where: E c is the back electromotive force after discrete Fourier transform;

[0031] After the calculation is completed, the proportion of the back electromotive force harmonic amplitude of the permanent magnet synchronous motor is calculated according to the following formula:

[0032] S E =(E c5f +E c7f +E c11f +E c13f ) / E cf

[0033] where: S E is the proportion of the back electromotive force harmonic amplitude of the permanent magnet synchronous motor;

[0034] E cf is the amplitude of E c at a frequency equal to f;

[0035] E c5f is the amplitude of E c at a frequency equal to 5f;

[0036] E c7f is the amplitude of E c at a frequency equal to 7f;

[0037] E c11f is the amplitude of E c at a frequency equal to 11f

[0038] E c13f is the amplitude of E c at a frequency equal to 13f.

[0039] Preferably, in step 3), the time-domain electromagnetic force calculation method of the permanent magnet synchronous motor is as follows: in the permanent magnet synchronous motor simulation calculation model, cut the stator teeth radially by n 2 mm, set the output torque of the rotor to the maximum torque required by the design, and respectively calculate once when the rotor rotates by n 1 ° under the conditions that the rotor speeds are n, 2*n, 3*n…14*n, record the time-domain electromagnetic force generated by the rotor at this time, calculate M times in total, record the time-domain electromagnetic forces at all stator tooth cutting positions at M transient moments, and decompose them in the radial and tangential directions.

[0040] Preferably, in step 4), the calculation method of the tangential force density of the permanent magnet synchronous motor includes the following steps:

[0041] Step 4.1) Perform Fourier decomposition in time on the tangential component forces of the time-domain electromagnetic forces at the cutting positions of each stator tooth under the condition that the rotor speed is n in step 3) to obtain the frequency-domain results of the tangential electromagnetic forces. The specific decomposition formula is:

[0042]

[0043] In the formula: is the tangential electromagnetic frequency-domain force of the mth tooth of the stator under the condition of the rotor speed of n;

[0044] is the transient tangential time-domain electromagnetic force of the mth tooth of the stator at the corresponding moment of the ith angle of the rotor under the condition of the rotor speed of n;

[0045] According to the above formula, calculate the tangential electromagnetic frequency-domain forces of the 1st, 2nd, 3rd,…, mth stator teeth in turn under the condition of the rotor speed of n;

[0046] After the calculation is completed, summarize the tangential electromagnetic frequency-domain forces of all stator teeth under the frequency conditions of ω = 2f; ω = 6f; ω = 12f, and perform spatial FFT decomposition according to the following formula;

[0047]

[0048] In the formula: FF tan n (space, ω) is the tangential electromagnetic frequency-domain spatial force of the rotor at the frequency of ω under the condition of the rotor speed of n;

[0049] Calculate and record the corresponding tangential electromagnetic frequency-domain spatial forces in three cases of space = 2p, ω = 2f; space = 0, ω = 6f; space = 0, ω = 12f according to the above formula; p is the number of pole pairs of the permanent magnet synchronous motor;

[0050] Step 4.2) Calculate the corresponding tangential electromagnetic frequency-domain spatial forces under the three conditions of space = 2p, ω = 2f; space = 0, ω = 6f; and space = 0, ω = 12f respectively when the rotor speed is 2*n, 3*n…14*n according to Step 4.1).

[0051] Preferably, in Step 5), the calculation method of the radial force density of the permanent magnet synchronous motor includes the following steps;

[0052] Step 5.1) Perform Fourier decomposition in time domain for the radial components of the time-domain electromagnetic forces at the cutting points of each stator tooth under the condition of rotor speed n in Step 3) one by one to obtain the frequency-domain results of the radial electromagnetic forces. The specific decomposition formula is:

[0053]

[0054] In the formula: is the radial electromagnetic frequency-domain force of the m-th stator tooth under the condition of rotor speed n;

[0055] is the transient tangential-radial time-domain electromagnetic force of the m-th stator tooth at the moment corresponding to the i-th angle of the rotor under the condition of rotor speed n;

[0056] According to the above formula, calculate the tangential electromagnetic frequency-domain forces of the 1st, 2nd, 3rd, …, m-th stator teeth under the condition of rotor speed n in turn;

[0057] After the calculation is completed, summarize the radial electromagnetic frequency-domain forces of all stator teeth under the frequency conditions of ω = 2f; ω = 6f; ω = 12f, and perform spatial FFT decomposition according to the following formula;

[0058]

[0059] In the formula: FF ran n(space, ω) is the radial electromagnetic frequency-domain spatial force of the rotor at the speed of n and frequency of ω;

[0060] Calculate and record the corresponding radial electromagnetic frequency-domain spatial forces under the three conditions of space = 2p, ω = 2f; space = 0, ω = 6f; space = 0, ω = 12f respectively according to the above formula; p is the number of pole pairs of the permanent magnet synchronous motor;

[0061] Step 5.2) Calculate the corresponding radial electromagnetic frequency-domain spatial forces under the three conditions of space = 2p, ω = 2f; space = 0, ω = 6f; space = 0, ω = 12f respectively when the rotor speed is 2*n, 3*n…14*n according to Step 5.1).

[0062] Preferably, in step 6), the method for extracting the stator structure parameters of the permanent magnet synchronous motor is as follows: Measure the stator outer diameter RR, the stator yoke thickness HH, and the stator slot width DD according to the permanent magnet synchronous motor simulation calculation model, and calculate the stator structure coefficient according to the following formula:

[0063]

[0064] In the formula: STR is the stator structure coefficient.

[0065] Preferably, in step 7), the method for analyzing the vibration transfer ability of the permanent magnet synchronous motor is as follows: Calculate the tangential electromagnetic force in the frequency domain space according to the following formula to obtain the tangential electromagnetic force coefficient;

[0066]

[0067] In the formula: FTAN is the tangential electromagnetic force coefficient;

[0068] Calculate the radial electromagnetic force in the frequency domain space according to the following formula to obtain the radial electromagnetic force coefficient;

[0069]

[0070] In the formula: FRAD is the tangential electromagnetic force coefficient;

[0071] Calculate the vibration transfer coefficient of the permanent magnet synchronous motor according to the following formula:

[0072] VRB co = 1 / CT + 1 / S E + 1 / FRAD + 1 / FTAN + STR

[0073] In the formula: VRB co is the vibration transfer coefficient of the permanent magnet synchronous motor;

[0074] Evaluate the vibration transfer ability of the permanent magnet synchronous motor according to the calculated vibration transfer coefficient of the permanent magnet synchronous motor.

[0075] Compared with the prior art, the present invention has the following advantages:

[0076] 1. The present invention clarifies the key design parameters of the permanent magnet synchronous motor that can suppress electromagnetic noise, and clarifies the quantifiable evaluation dimensions; it provides an important basis for the product in the early stage of project development.

[0077] 2. The present invention can realize the rapid iteration of the scheme, the efficient optimization of the product, and the early identification of risk problems without high-frequency electromagnetic noise.

[0078] 3. The method proposed by the present invention can realize the rapid performance comparison of the standard sample and the self-developed sample. Description of the Drawings

[0079] Appendix Figure 1 This is the simulation calculation model diagram of the permanent magnet synchronous motor in the method for analyzing the vibration transfer ability of the vehicle-mounted permanent magnet synchronous motor of the present invention;

[0080] Appendix Figure 2 This is the transient cogging torque diagram of the permanent magnet synchronous motor obtained by calculation in the method for analyzing the vibration transfer ability of the vehicle-mounted permanent magnet synchronous motor of the present invention;

[0081] Appendix Figure 3 This is the transient back electromotive force diagram of the permanent magnet synchronous motor obtained by calculation in the method for analyzing the vibration transfer ability of the vehicle-mounted permanent magnet synchronous motor of the present invention;

[0082] Appendix Figure 4 This is the back electromotive force harmonic amplitude diagram of the permanent magnet synchronous motor obtained by calculation in the method for analyzing the vibration transfer ability of the vehicle-mounted permanent magnet synchronous motor of the present invention;

[0083] Appendix Figure 5 This is the schematic diagram of cutting out the stator teeth part in the method for analyzing the vibration transfer ability of the vehicle-mounted permanent magnet synchronous motor of the present invention;

[0084] Appendix Figure 6 This is the schematic diagram of the stator structure parameters in the method for analyzing the vibration transfer ability of the vehicle-mounted permanent magnet synchronous motor of the present invention.

[0085] Description of the reference numerals: Rotor 1, Stator 2. Detailed Description of the Invention

[0086] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and illustrated herein can generally be arranged and designed in a variety of different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0087] In this specific embodiment, the method of the present invention will be described in detail in combination with a specific vehicle-mounted permanent magnet synchronous motor

[0088] A method for analyzing the vibration transfer ability of a vehicle-mounted permanent magnet synchronous motor first establishes a simulation calculation model of the permanent magnet synchronous motor. In this specific embodiment, the rotor of the permanent magnet synchronous motor has 12 poles and the stator has 72 slots. The simulation calculation model is shown in Figure 1; Since the rotor 1 and stator 2 of the permanent magnet synchronous motor are symmetric about the rotor pole circumference, only a 1 / 12th model needs to be established during simulation. If the rotor has 8 poles, a 1 / 8th model is established; if the rotor has 6 poles, a 1 / 6th model is established. In this specific embodiment, the rotor has 12 poles, so a 1 / 12th model is established.

[0089] After establishing the simulation calculation model of the permanent magnet synchronous motor, the following steps are used for specific analysis:

[0090] Step 1) Calculate the peak-to-peak value of the cogging torque of the permanent magnet synchronous motor.

[0091] Set the control current in the simulation calculation model of the permanent magnet synchronous motor to 0 and the rotor speed to n. In this specific embodiment, the rotor speed n is 1000 rpm. Set the rotor to perform a calculation every time it rotates n 1 °. In this specific embodiment, set the rotor to perform a calculation every time it rotates 0.25°, that is, n 1 = 0.25; record the torque generated by the rotor at this time, calculate M times in total, and record M torque values. In this specific embodiment, M = 1440, then 0.25° * 1440 = 360°, so that the equivalent space rotation of the rotor is 360°. Then calculate the peak-to-peak value of the cogging torque of this permanent magnet synchronous motor according to the following formula, and the recorded result is as Figure 2 shown:

[0092] CT = MAX(coqt(θ 1 ), coqt(θ 2 ),... coqt(θ M )) / MIN(coqt(θ 1 ), coqt(θ 2 ),... coqt(θ M ))

[0093] Substituting M = 1440 into the above formula, we can get:

[0094] CT = MAX(coqt(θ 1 ), coqt(θ 2 ),... coqt(θ 1440 )) / MIN(coqt(θ 1 ), coqt(θ 2 ),... coqt(θ 1440 ))

[0095] In the formula: CT is the peak-to-peak value of the cogging torque of the permanent magnet synchronous motor for heat generation;

[0096] MAX() is the maximum value among all data;

[0097] MIN() is the minimum value among all data;

[0098] coqt(θ i ) is the torque generated by the rotor calculated for the i-th angle, where i = 1, 2, 3... 1440.

[0099] The CT value calculated for the permanent magnet synchronous motor in this specific embodiment is: 0.4 Nm.

[0100] Step 2) Calculate the proportion of the harmonic amplitude of the back electromotive force of the permanent magnet synchronous motor.

[0101] Set the control current in the permanent magnet synchronous motor simulation calculation model to 0, and set the rotor speed to n. In this specific embodiment, the rotor speed n is 1000 rpm; set the rotor to perform a calculation every time it rotates n 1 °. In this specific embodiment, set the rotor to perform a calculation every time it rotates 0.25°. Record the transient magnetic flux value generated by the rotor at this time, calculate M times in total, and record M transient magnetic flux values. In this specific embodiment, M = 1440, then 0.25° * 1440 = 360°, so that the equivalent space rotation of the rotor is 360°. Then calculate the transient back electromotive force of the permanent magnet synchronous motor according to the following formula, and the calculated result is as shown in the appendix Figure 3 as follows:

[0102] e c (θ i ) = 2πNφ i k / f

[0103] In the formula: e c (θ i ) is the transient back electromotive force calculated for the i-th angle;

[0104] N is the number of turns of the stator winding;

[0105] φ i is the transient magnetic flux value calculated for the i-th angle;

[0106] k is the air-gap waveform coefficient;

[0107] f is the power supply frequency;

[0108] After the calculation is completed, perform a discrete Fourier transform on the M calculated transient back electromotive forces according to the following formula:

[0109]

[0110] Substitute M = 1440 into the above formula to obtain:

[0111]

[0112] In the formula: E cis the back electromotive force after discrete Fourier transform;

[0113] After the calculation is completed, calculate the proportion of the harmonic amplitude of the back electromotive force of the permanent magnet synchronous motor according to the following formula:

[0114] S E =(E c5f +E c7f +E c11f +E c13f ) / E cf

[0115] In the formula: S E is the proportion of the harmonic amplitude of the back electromotive force of the permanent magnet synchronous motor;

[0116] E cf is the amplitude of E c at a frequency equal to f;

[0117] E c5f is the amplitude of E c at a frequency equal to 5f;

[0118] E c7f is the amplitude of E c at a frequency equal to 7f;

[0119] E c11f is the amplitude of E c at a frequency equal to 11f

[0120] E c13f is the amplitude of E c at a frequency equal to 13f.

[0121] The results calculated in this specific embodiment are as shown in the appendix Figure 4 The SE value calculated for this product is: 0.127.

[0122] Step 3) Calculate the time-domain electromagnetic force of the permanent magnet synchronous motor.

[0123] In the simulation calculation model of the permanent magnet synchronous motor, cut the stator teeth radially by n 2 mm. In this specific embodiment, cut the stator teeth radially by 2 mm, that is, n 2 = 2. The model after cutting is as shown in the appendix Figure 5 The dotted part in the appendix Figure 5 is the cut stator teeth. Set the output torque of the rotor to the maximum torque required by the design, and set the rotor to rotate n 1 each time at rotor speeds of n, 2*n, 3*n... 14*nPerform a calculation, record the time-domain electromagnetic force generated by the rotor at this time, perform the calculation M times, record the time-domain electromagnetic forces at all stator tooth cutting positions at M transient moments, and decompose them in the radial and tangential directions. In this specific embodiment, the rotor is set to perform a calculation every 0.25° of rotation under the conditions of rotational speeds of 1000 rpm, 2000 rpm, …, 14000 rpm, and the torque generated by the rotor at this time is recorded. The calculation is performed 1440 times in total, and 1440 transient moments are recorded. The time-domain radial and tangential electromagnetic forces of the stator tooth cutting part calculated by this product are shown in Table 1 and Table 2.

[0124] Table 1: Time-domain Radial Electromagnetic Force of Stator Tooth Cutting Part

[0125]

[0126]

[0127] Table 2 Time-domain Tangential Electromagnetic Force of Stator Tooth Cutting Part

[0128]

[0129]

[0130] Step 4) Calculate the tangential force density of the permanent magnet synchronous motor.

[0131] Step 4.1) Perform a Fourier decomposition in time for each tangential component of the time-domain electromagnetic force at each stator tooth cutting position under the condition of rotor speed n (1000 rpm) in Step 3) to obtain the frequency-domain result of the tangential electromagnetic force. The specific decomposition formula is:

[0132]

[0133] In the formula: is the tangential electromagnetic frequency-domain force of the m-th stator tooth under the condition of rotor speed n;

[0134] is the transient tangential time-domain electromagnetic force of the m-th stator tooth at the moment corresponding to the i-th angle of the rotor under the condition of rotor speed n;

[0135] Substitute n = 1000, m = 1, and M = 1440 into the above formula to obtain the calculation formula for the tangential electromagnetic frequency-domain force of the first stator tooth under the condition of rotor speed 1000 rpm:

[0136]

[0137] In the formula: represents the tangential electromagnetic frequency-domain force of the first stator tooth under the condition of rotor speed 1000 rpm; It represents the transient tangential time-domain electromagnetic force of the first tooth of the stator at the corresponding moment of the i-th angle when the rotor rotates at a speed of 1000 rpm.

[0138] According to the above formula, the tangential electromagnetic frequency-domain forces of the 2nd, 3rd, …, m-th stator teeth at the rotor speed of n are calculated in sequence;

[0139] After the calculation is completed, the tangential electromagnetic frequency-domain forces of all stator teeth under the frequency conditions of ω = 2f; ω = 6f; ω = 12f are summarized and decomposed by spatial FFT according to the following formula;

[0140]

[0141] In the formula: FF tan n (space, ω) is the tangential electromagnetic frequency-domain spatial force of the rotor at the speed of n and the frequency of ω;

[0142] Substituting n = 1000 into the above formula, we can get:

[0143]

[0144] In the formula: FF tan1000 (space, ω) represents the tangential electromagnetic frequency-domain spatial force at the frequency of ω when the rotor rotates at a speed of 1000 rpm.

[0145] Calculate and record the corresponding tangential electromagnetic frequency-domain spatial forces under the three conditions of space = 2p, ω = 2f; space = 0, ω = 6f; space = 0, ω = 12f according to the above formula; p is the number of pole pairs of the permanent magnet synchronous motor; in this embodiment, the number of rotor poles is 12, then the number of pole pairs = 12 / 2 = 6, p = 6.

[0146] Step 4.2) Calculate the corresponding tangential electromagnetic frequency-domain spatial forces under the three conditions of space = 2p, ω = 2f; space = 0, ω = 6f; space = 0, ω = 12f when the rotor speeds are 2*n, 3*n…14*n respectively according to Step 4.1), that is, in this specific embodiment, it is necessary to calculate the corresponding tangential electromagnetic frequency-domain spatial forces when the rotor speeds are 2000 rpm, 3000 rpm, …, 14000 rpm respectively. The results of the tangential electromagnetic frequency-domain spatial forces calculated in this specific embodiment are shown in Table 3:

[0147] Table 3: Results of tangential electromagnetic frequency-domain spatial forces

[0148] Rotational speed 1000 rpm 2000 rpm 3000 rpm 4000 rpm 5000 rpm 6000 rpm 7000 rpm (space=2p, ω=2f) 46000 46000 46000 46000 46000 46000 46000 (space=0, ω=6f) 200 200 200 200 200 200 200 (space=0, ω=12f) 320 320 320 320 320 320 320 Rotational speed 8000 rpm 9000 rpm 10000 rpm 11000 rpm 12000 rpm 13000 rpm 14000 rpm (space=2p, ω=2f) 46000 46000 46000 44000 42000 40000 40000 (space=0, ω=6f) 200 200 200 260 310 330 380 (space=0, ω=12f) 320 320 320 380 400 500 550

[0149] Step 5) Calculate the radial force density of the permanent magnet synchronous motor.

[0150] Step 5.1) The radial components of the time-domain electromagnetic force at each stator tooth cutting point under the condition of the rotor speed n (1000 rpm) in step 3) are decomposed one by one in time by Fourier, and the frequency domain results of the radial electromagnetic force are obtained. The specific decomposition formula is:

[0151]

[0152] Where: is the radial electromagnetic frequency domain force of the mth stator tooth under the condition of rotor speed n;

[0153] is the transient radial time-domain electromagnetic force of the mth stator tooth at the moment corresponding to the i-th angle of the rotor under the condition of rotor speed n.

[0154] Substituting n=1000, m=1, M=1440 into the above formula, we can obtain the radial electromagnetic frequency domain force calculation formula of the first stator tooth under the condition of rotor speed of 1000rpm:

[0155]

[0156] Where: It represents the radial electromagnetic frequency domain force of the first stator tooth under the condition of rotor speed of 1000rpm; It represents the transient radial time-domain electromagnetic force of the first stator tooth at the moment corresponding to the i-th angle of the rotor under the condition of a rotor speed of 1000 rpm.

[0157] According to the above formula, the tangential electromagnetic frequency domain force of the 2nd, 3rd, ..., mth stator teeth under the condition of rotor speed n is calculated in turn;

[0158] After the calculation is completed, the radial electromagnetic frequency domain forces of all stator teeth under the frequency conditions of ω=2f; ω=6f; ω=12f are summarized and spatial FFT decomposition is performed according to the following formula;

[0159]

[0160] Where: FF rad n(space, ω) is the radial electromagnetic frequency domain space force when the rotor is at a speed of n and a frequency of ω;

[0161] Substituting n=1000 into the above formula yields:

[0162]

[0163] Where: FF rad1000 (space, ω) represents the radial electromagnetic frequency domain spatial force with a frequency of ω under the condition of a rotor speed of 1000 rpm.

[0164] Calculate and record the corresponding radial electromagnetic frequency-domain space forces under the three conditions of space = 2p, ω = 2f; space = 0, ω = 6f; space = 0, ω = 12f respectively according to the above formula; p is the number of pole pairs of the permanent magnet synchronous motor; in this embodiment, the number of rotor poles is 12, then the number of pole pairs = 12 / 2 = 6, p = 6.

[0165] Step 5.2) According to Step 5.1), calculate the corresponding radial electromagnetic frequency-domain space forces under the conditions of rotor speeds of 2*n, 3*n…14*n, that is, in this specific embodiment, it is necessary to calculate the corresponding radial electromagnetic frequency-domain space forces under the conditions of rotor speeds of 2000 rpm, 3000 rpm,…, 14000 rpm under the three conditions of space = 2p, ω = 2f; space = 0, ω = 6f; space = 0, ω = 12f. The results of the radial electromagnetic frequency-domain space forces calculated in this specific embodiment are shown in Table 4:

[0166] Table 4: Results of Radial Electromagnetic Frequency-Domain Space Forces

[0167] Rotational speed 1000 rpm 2000 rpm 3000 rpm 4000 rpm 5000 rpm 6000 rpm 7000 rpm (space=2p, ω=2f) 220000 220000 220000 220000 220000 220000 220000 (space=0, ω=6f) 2100 2100 2100 2100 2100 2100 2100 (space=0, ω=12f) 1500 1500 1500 1500 1500 1500 1500 Rotational speed 8000 rpm 9000 rpm 10000 rpm 11000 rpm 12000 rpm 13000 rpm 14000 rpm (space=2p, ω=2f) 220000 220000 220000 220000 150000 1400000 1000000 (space=0, ω=6f) 2100 2100 2100 2300 2600 3000 3300 (space=0, ω=12f) 1500 1500 1500 1550 1700 1400 1700

[0168] Step 6) Extract the stator structure parameters of the permanent magnet synchronous motor.

[0169] The method for extracting the stator structure parameters of the permanent magnet synchronous motor is as follows: Measure the outer diameter RR of the stator, the thickness HH of the stator yoke, and the slot width DD of the stator according to the permanent magnet synchronous motor simulation calculation model, as specifically shown in the appendix Figure 6 and calculate the stator structure coefficient according to the following formula:

[0170]

[0171] In the formula: STR is the stator structure coefficient. In this specific embodiment, RR is 220 mm, HH is 20 mm, DD is 4 mm, and the calculated STR is: 2.18.

[0172] Step 7) Conduct an analysis of the vibration transfer ability of the permanent magnet synchronous motor.

[0173] Calculate the tangential electromagnetic frequency-domain space force according to the following formula to obtain the tangential electromagnetic force coefficient;

[0174]

[0175] In the formula: FTAN is the tangential electromagnetic force coefficient;

[0176] Substitute n = 1000 into the above formula to get:

[0177]

[0178] The FTAN value calculated in this specific embodiment is: 0.772.

[0179] Calculate the radial electromagnetic force in the frequency domain space according to the following formula to obtain the radial electromagnetic force coefficient;

[0180]

[0181] In the formula: FRAD is the tangential electromagnetic force coefficient;

[0182] Substitute n = 1000 into the above formula to get:

[0183]

[0184] The FRAD value calculated in this specific embodiment is: 1.776.

[0185] Then calculate the vibration transfer coefficient of the permanent magnet synchronous motor according to the following formula:

[0186] VRB co = 1 / CT + 1 / S E + 1 / FRAD + 1 / FTAN + STR

[0187] In the formula: VRB co is the vibration transfer coefficient of the permanent magnet synchronous motor; the VRB co value calculated for this product is: 14.41.

[0188] Evaluate the vibration transfer ability of the permanent magnet synchronous motor according to the calculated vibration transfer coefficient of the permanent magnet synchronous motor.

[0189] Score the vibration transfer ability of the permanent magnet synchronous motor according to the standard in Table 5. The higher the score, the better the ability of the design scheme to suppress the outward transfer of vibration, and the more conducive to reducing the noise inside the vehicle during driving. The score of this product is 6 points.

[0190] Table 5: Scoring table for the vibration transfer ability of the permanent magnet synchronous motor

[0191] Score 1 2 3 4 5 6 7 8 9 10 Range 4≤ 4～6 6～8 8～10 10～13 13～16 16～19 19～22 22～25 ≥25

[0192] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit the technical solutions. Those of ordinary skill in the art should understand that any modifications or equivalent replacements made to the technical solutions of the present invention without departing from the purpose and scope of the present technical solutions shall be covered by the scope of the claims of the present invention.

Claims

1. A method for analyzing the vibration transmission capability of a permanent magnet synchronous motor for a vehicle, characterized in that: Establishing a simulation calculation model of a permanent magnet synchronous motor includes the following steps: Step 1) calculating the peak-to-peak value of the cogging torque of the permanent magnet synchronous motor; Step 2) calculating the proportion of the back-EMF harmonic amplitude of the permanent magnet synchronous motor; Step 3) calculating the time domain electromagnetic force of the permanent magnet synchronous motor; Step 4) calculating the tangential force density of the permanent magnet synchronous motor; Step 5) calculating the radial force density of the permanent magnet synchronous motor; Step 6) extracting the stator structural parameters of the permanent magnet synchronous motor; Step 7) Analyze the vibration transmission capability of the permanent magnet synchronous motor.

2. The method for analyzing the vibration transfer capability of a permanent magnet synchronous motor for a vehicle according to claim 1, characterized in that: In step 1), the calculation method of the peak-to-peak value of the cogging torque of the permanent magnet synchronous motor is as follows: the control current in the permanent magnet synchronous motor simulation calculation model is set to 0, the rotor speed is set to n, and the calculation is performed once every time the rotor rotates n1°, and the torque generated by the rotor at this time is recorded, and the calculation is accumulated M times, and M torque values ​​are recorded, and n1°*M=360°, so that the equivalent spatial rotation of the rotor is 360°, and the peak-to-peak value of the cogging torque of the permanent magnet synchronous motor is calculated according to the following formula: CT:MAX(coqt(θ1),coqt(θ2),...coqt(θ M )) / MIN(coqt(θ1),coqt(θ2),...coqt(θ M )) Where: CT is the peak-to-peak value of the thermal cogging torque of the permanent magnet synchronous motor; MAX() is the maximum value of all data; MIN() is the minimum value of all data; coqt(θ i ) is the torque generated by the rotor calculated at the i-th angle, i=1, 2, 3...M.

3. The method for analyzing the vibration transmission capability of a permanent magnet synchronous motor for a vehicle according to claim 2, characterized in that: In step 2), the calculation method for the proportion of the harmonic amplitude of the back electromotive force of the permanent magnet synchronous motor is as follows: the control current in the simulation calculation model of the permanent magnet synchronous motor is set to 0, and the rotor speed is set to n; the rotor is set to perform a calculation every time it rotates n1°, and the transient magnetic flux value generated by the rotor at this time is recorded, and the calculation is accumulated M times, M transient magnetic flux values ​​are recorded, and n1°*M=360°, so that the equivalent spatial rotation of the rotor is 360°, and then the transient back electromotive force of the permanent magnet synchronous motor is calculated according to the following formula: e c (i i )=2π N F i k / f Where: e c (θ i ) is the transient back EMF calculated at the i-th angle; N is the number of stator winding turns; φ i is the transient magnetic flux value calculated for the i-th angle; k is the air gap waveform coefficient; f is the power frequency; After the calculation is completed, the M transient back EMFs calculated are subjected to discrete Fourier transform according to the following formula: Where: E c is the back EMF after discrete Fourier transform; After the calculation is completed, the proportion of the back-EMF harmonic amplitude of the permanent magnet synchronous motor is calculated according to the following formula: S E =(And c5f +E c7f +E c11f +E c13f ) / AND cf Where: S E is the proportion of the back-EMF harmonic amplitude of the permanent magnet synchronous motor; E cf For E c The amplitude at a frequency equal to f; E c5f For E c The amplitude at a frequency equal to 5f; E c7f For E c The amplitude at a frequency equal to 7f; E c11f For E c The amplitude at a frequency of 11f E c13f For E c Amplitude at a frequency equal to 13f.

4. The method for analyzing the vibration transmission capability of a permanent magnet synchronous motor for a vehicle according to claim 3, characterized in that: In step 3), the time domain electromagnetic force calculation method of the permanent magnet synchronous motor is as follows: in the permanent magnet synchronous motor simulation calculation model, the stator teeth are cut n2mm radially, the output torque of the rotor is set to the maximum torque required by the design, and the rotor is set to perform a calculation every time it rotates n1° under the conditions of rotor speeds of n, 2*n, 3*n...14*n, and the time domain electromagnetic force generated by the rotor at this time is recorded. The calculation is accumulated M times, and the time domain electromagnetic forces at all stator tooth cutting points at M transient moments are recorded, and decomposed according to radial and tangential directions.

5. The method for analyzing the vibration transmission capability of a permanent magnet synchronous motor for a vehicle according to claim 4, characterized in that: In step 4), the method for calculating the tangential force density of the permanent magnet synchronous motor includes the following steps: Step 4.1) The tangential components of the time-domain electromagnetic force at each stator tooth cutting point under the condition of the rotor speed n in step 3) are decomposed one by one in time by Fourier decomposition to obtain the frequency domain result of the tangential electromagnetic force. The specific decomposition formula is: Where: is the tangential electromagnetic frequency domain force of the mth stator tooth under the condition of rotor speed n; is the transient tangential time-domain electromagnetic force of the mth stator tooth at the moment corresponding to the i-th angle of the rotor under the condition of rotor speed n; According to the above formula, the tangential electromagnetic frequency domain force of the 1st, 2nd, 3rd, ..., mth stator teeth under the condition of rotor speed n is calculated in turn; After the calculation is completed, the tangential electromagnetic frequency domain forces of all stator teeth under the frequency conditions of ω=2f; ω=6f; ω=12f are summarized and spatial FFT decomposition is performed according to the following formula; Where: FF tan n (space, ω) is the tangential electromagnetic frequency domain space force when the rotor is at a speed of n and a frequency of ω; According to the above formula, calculate and record the corresponding tangential electromagnetic frequency domain space force in the three cases of space = 2p, ω = 2f; space = 0, ω = 6f; space = 0, ω = 12f; p is the number of pole pairs of the permanent magnet synchronous motor; Step 4.2) According to step 4.1), the corresponding tangential electromagnetic frequency domain spatial forces are calculated under the conditions of rotor speed of 2*n, 3*n...14*n, space=2p, ω=2f; space=0, ω=6f; space=0, ω=12f.

6. The method for analyzing the vibration transmission capability of a permanent magnet synchronous motor for a vehicle according to claim 5, characterized in that: In step 5), the method for calculating the radial force density of the permanent magnet synchronous motor comprises the following steps: Step 5.1) The radial components of the time-domain electromagnetic force at each stator tooth cutting point under the condition of the rotor speed being n in step 3) are subjected to Fourier decomposition in time one by one to obtain the frequency-domain result of the radial electromagnetic force. The specific decomposition formula is: Where: is the radial electromagnetic frequency domain force of the mth stator tooth under the condition of rotor speed n; is the transient radial time-domain electromagnetic force of the mth stator tooth at the corresponding moment of the i-th angle under the condition of rotor speed n; According to the above formula, the tangential electromagnetic frequency domain force of the 1st, 2nd, 3rd, ..., mth stator teeth under the condition of rotor speed n is calculated in turn; After the calculation is completed, the radial electromagnetic frequency domain forces of all stator teeth under the frequency conditions of ω=2f; ω=6f; ω=12f are summarized and spatial FFT decomposition is performed according to the following formula; Where: FF rad n (space, ω) is the radial electromagnetic frequency domain space force when the rotor is at a speed of n and a frequency of ω; According to the above formula, calculate and record the corresponding radial electromagnetic frequency domain space force in the three cases of space = 2p, ω = 2f; space = 0, ω = 6f; space = 0, ω = 12f; p is the number of pole pairs of the permanent magnet synchronous motor; Step 5.2) According to step 5.1), the radial electromagnetic frequency domain spatial force corresponding to the three cases of space = 2p, ω = 2f; space = 0, ω = 6f; space = 0, ω = 12f is calculated respectively under the conditions of rotor speed of 2*n, 3*n...14*n.

7. The method for analyzing the vibration transmission capability of a permanent magnet synchronous motor for a vehicle according to claim 6, characterized in that: In step 6), the method for extracting the stator structural parameters of the permanent magnet synchronous motor is: according to the permanent magnet synchronous motor simulation calculation model, the stator outer diameter RR, the stator yoke thickness HH, and the stator slot width DD are measured, and the stator structural coefficient is calculated according to the following formula: Where: STR is the stator structure coefficient.

8. The method for analyzing the vibration transmission capability of a permanent magnet synchronous motor for a vehicle according to claim 7, characterized in that: In step 7), the method for analyzing the vibration transfer capability of the permanent magnet synchronous motor is: the tangential electromagnetic frequency domain spatial force is calculated according to the following formula to obtain the tangential electromagnetic force coefficient; Where: FTAN is the tangential electromagnetic force coefficient; The radial electromagnetic frequency domain spatial force is calculated according to the following formula to obtain the radial electromagnetic force coefficient; Where: FRAD is the tangential electromagnetic force coefficient; The vibration transfer coefficient of the permanent magnet synchronous motor is calculated according to the following formula: VRB co =1 / CT+1 / S E +1 / FRAD+1 / FTAN+STR Where: VRB co is the vibration transfer coefficient of the permanent magnet synchronous motor; The vibration transfer capability of the permanent magnet synchronous motor is evaluated according to the calculated vibration transfer coefficient of the permanent magnet synchronous motor.

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