Synchronous electric drive NVH (Noise Vibration and Harshness) optimization method and device, equipment and medium

Abstract

The invention discloses a synchronous electric drive NVH optimization method, device and equipment and a medium, and the method comprises the steps: obtaining the reference frequency of a vehicle motor in a vehicle operation process, and judging whether the reference frequency is in a preset variable carrier frequency region or not; if yes, randomly generating a first random number, and determining a random carrier frequency according to the first random number, the reference frequency and a set carrier frequency change amplitude; according to the first random number, the random carrier frequency and a set carrier amplitude, determining a first loading slope of a first half period carrier and a second loading slope of a second half period carrier in a current carrier period to obtain a first carrier; and comparing the first carrier wave with a first modulated wave, and outputting an optimized PWM signal, the first modulated wave being generated according to the first carrier wave.

Description

Technical Field

[0001] The present invention relates to the field of permanent magnet synchronous motor control, and in particular to a synchronous electric drive NVH optimization method, device, equipment and medium. Background Art

[0002] The NVH (Noise, Vibration, and Harshness) performance of electric vehicles is one of the most important performance indicators for the entire vehicle, directly affecting the driving and riding experience. The drive motor is the power source of the electric vehicle, and its NVH performance is a key factor influencing the NVH performance of the entire vehicle. The permanent magnet synchronous motor used in electric vehicle traction is required to operate at low speed, high torque, and high speed, constant power. The high current at the low-speed, high-torque operating point and the magnetic field distortion caused by high-speed weak magnetic field may increase the amplitude of the electromagnetic force acting on the motor structure, easily causing large electromagnetic vibration noise. At the same time, the opening and closing of the controller switch tube will also generate vibration noise near the switching frequency and its multiples, thereby affecting the NVH performance of the electric vehicle. Summary of the Invention

[0003] The embodiments of the present application provide a synchronous electric drive NVH optimization method, device, equipment and medium.

[0004] In a first aspect, the present invention provides the following technical solutions through an embodiment of the present invention:

[0005] A synchronous electric drive NVH optimization method includes: during vehicle operation, obtaining a reference frequency of a vehicle motor, and determining whether the reference frequency is in a preset variable carrier frequency region; if so, randomly generating a first random number, and determining a random carrier frequency based on the first random number, the reference frequency, and a set amplitude of carrier frequency change; determining a first loading slope of the carrier in the first half cycle and a second loading slope of the carrier in the second half cycle within a current carrier cycle based on the first random number, the random carrier frequency, and a set carrier amplitude, to obtain a first carrier; comparing the first carrier with a first modulation wave, and outputting an optimized PWM signal, wherein the first modulation wave is generated based on the first carrier.

[0006] Preferably, the method also includes: if the carrier frequency is in a fixed carrier frequency area, randomly generating a second random number; determining the third loading slope of the carrier in the first half cycle and the fourth loading slope of the carrier in the second half cycle within the carrier period of the fixed carrier frequency area according to the second random number, the fixed carrier period and the set carrier amplitude, and obtaining a second carrier, wherein the fixed carrier period is determined according to the carrier frequency; comparing the second carrier with the second modulation wave, and outputting an optimized PWM signal, wherein the second modulation wave is generated according to the second carrier.

[0007] Preferably, the randomly generating the first random number includes: randomly generating the first random number by a linear congruential method.

[0008] Preferably, after outputting the optimized PWM signal, the method further includes: obtaining six non-zero vectors and two zero vectors in the three-phase voltage space vector of the vehicle motor, wherein the six non-zero vectors and the two zero vectors form a hexagonal structure containing six sectors; obtaining a reference voltage vector in the sector based on two adjacent non-zero vectors and two zero vectors, and for the reference voltage vector in each sector, determining the action time of two adjacent non-zero vectors and the action time of two zero vectors in each sector based on the sector where the reference voltage vector is located; randomly adjusting the action time of the two zero vectors to obtain the action time of each of the two adjusted zero vectors, wherein the sum of the action time of the two adjusted zero vectors remains unchanged; determining the vector switching point corresponding to each sector based on the action time of the two adjusted zero vectors and the action time of the two adjacent non-zero vectors in each sector, and generating an SVPWM modulation waveform.

[0009] Preferably, the randomly adjusting the action time of the two zero vectors to obtain the adjusted action time of each of the two zero vectors includes: bringing the action time of the two zero vectors and the set coefficient into a preset relationship model, randomly adjusting the set coefficient, and obtaining the adjusted action time of each of the two zero vectors.

[0010] Preferably, before obtaining the reference frequency of the vehicle motor, it also includes: obtaining the vehicle motor acceleration, torque and motor electrical angle; determining the open-loop injected harmonic dq axis voltage based on the motor acceleration, the torque and a preset N-th two-dimensional open-loop voltage table, and performing angle conversion according to the motor electrical angle and the preset N-th harmonic to obtain the N-th harmonic electrical angle, wherein the preset N-th two-dimensional open-loop voltage table includes the correspondence between the motor acceleration, torque and the open-loop injected harmonic dq axis voltage; performing an inverse park transformation on the open-loop injected harmonic dq axis voltage and the N-th harmonic electrical angle to obtain the α-axis voltage component and the β-axis voltage component required for N-th harmonic injection; superimposing the α-axis voltage component with the α-axis fundamental voltage component, and superimposing the β-axis voltage component with the β-axis fundamental voltage component to obtain the superimposed α-axis voltage output and the superimposed β-axis voltage output.

[0011] Preferably, the preset Nth order two-dimensional open-loop voltmeter is obtained by the following steps: using a test control console to perform Nth order open-loop injection harmonic dq-axis voltage calibration on the motor to establish an Nth order two-dimensional open-loop voltmeter, wherein the Nth order is 5th, 7th, 11th or 13th.

[0012] In a second aspect, the present invention provides the following technical solution through an embodiment of the present invention:

[0013] A synchronous electric drive NVH optimization device, comprising:

[0014] An acquisition module is used to acquire a reference frequency of the vehicle motor during vehicle operation and determine whether the reference frequency is within a preset variable carrier frequency range;

[0015] a random carrier frequency determination module, configured to randomly generate a first random number if the reference frequency is within a preset variable carrier frequency region, and determine a random carrier frequency based on the first random number, the reference frequency, and a set amplitude of carrier frequency variation;

[0016] A first carrier determination module is configured to determine a first loading slope of the carrier in the first half of the current carrier cycle and a second loading slope of the carrier in the second half of the current carrier cycle according to the first random number, the random carrier frequency, and a set carrier amplitude, to obtain a first carrier;

[0017] The first optimization module is configured to compare the first carrier wave with a first modulation wave and output an optimized PWM signal, where the first modulation wave is generated according to the first carrier wave.

[0018] In a third aspect, the present invention provides the following technical solution through an embodiment of the present invention:

[0019] An electronic device comprises: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the steps of any one of the methods described in the first aspect are implemented.

[0020] In a fourth aspect, the present invention provides the following technical solution through an embodiment of the present invention:

[0021] A computer-readable storage medium stores a computer program, which, when executed by a processor, implements the steps of the method described in any one of the first aspects above.

[0022] One or more technical solutions provided in the embodiments of this application have at least the following technical effects or advantages:

[0023] The synchronous electric drive NVH optimization method provided by an embodiment of the present invention first determines the reference frequency according to the vehicle motor speed, and then determines whether the reference frequency is in a preset variable carrier frequency area. If so, a random number is generated and combined with the amplitude of the reference frequency and the set carrier frequency change to obtain a random carrier frequency. Compared with the reference frequency, the random carrier frequency is randomly scattered. Then, the first loading slope of the carrier in the first half cycle and the second loading slope of the carrier in the second half cycle within the carrier period are obtained to obtain a modulated carrier. The carrier is compared with the modulated wave to obtain an optimized PWM signal. A control method for realizing random adjustment of the PWM carrier slope of the motor controller proposed in this application is adopted, and a random carrier frequency change function is integrated into the NVH software to form a function with the fundamental frequency carrier as the standard and random width change near it, thereby dispersing the concentrated ability and better solving the problem that the output voltage generates a large number of high-order harmonics at the switching frequency and its integer multiples, which brings a large amount of electromagnetic noise and interference. The carrier frequency of the inverter can be changed according to a random function, and the PWM harmonics originally concentrated near the carrier frequency and its integer multiples can be dispersed to a larger frequency range, reducing the larger electromagnetic vibration noise, achieving the purpose of suppressing PWM harmonics and improving noise, and effectively improving the vehicle NVH performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following is a brief introduction to the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0025] Figure 1 Flowchart of the synchronous electric drive NVH optimization method in an embodiment of the present invention;

[0026] Figure 2 Schematic diagram of the structure of a three-phase bridge inverter circuit in an embodiment of the present invention;

[0027] Figure 3 This is a structural distribution diagram of six equal sectors in an embodiment of the present invention;

[0028] Figure 4 Schematic diagram of a reference voltage vector Vref in an embodiment of the present invention;

[0029] Figure 5 This is a state diagram of the three-phase switch action when the voltage vector is in the first sector in an embodiment of the present invention;

[0030] Figure 6 This is a simulation diagram of a fixed carrier frequency in an embodiment of the present invention;

[0031] Figure 7This is a simulation diagram of random variable carrier frequency + random SVPWM in an embodiment of the present invention;

[0032] Figure 8 Schematic diagram of the structure of the test control console in an embodiment of the present invention;

[0033] Figure 9 Schematic diagram of a process for obtaining a superimposed α-axis voltage output and a superimposed β-axis voltage output in an embodiment of the present invention;

[0034] Figure 10 This is a framework diagram of a synchronous electric drive NVH optimization system in an embodiment of the present invention;

[0035] Figure 11 Schematic diagram of the structure of the synchronous electric drive NVH optimization device in an embodiment of the present invention;

[0036] Figure 12 Schematic diagram of the structure of an electronic device in an embodiment of the present invention. DETAILED DESCRIPTION

[0037] It's generally believed that increasing the inverter's switching frequency can reduce the current amplitude of PWM harmonics. When the switching frequency reaches a certain level, the motor system's electromagnetic noise frequency can exceed the upper limit of human hearing. However, as the switching frequency increases, the impact of dead time gradually increases, significantly increasing the inverter's switching losses. Random switching frequency technology allows the inverter's carrier frequency to vary according to a random function, dispersing PWM harmonics, previously concentrated near the carrier frequency and its integer multiples, across a wider frequency range, thereby suppressing PWM harmonics and improving noise. However, with traditional SVPWM methods, the output voltage at the switching frequency and its integer multiples generates a large number of high-order harmonics, which can lead to significant electromagnetic noise and interference.

[0038] In view of this, the embodiments of the present application provide a synchronous electric drive NVH optimization method, device, equipment and medium. The method can realize random adjustment of the PWM carrier slope of the motor controller, solve or partially solve the problem of a large amount of electromagnetic noise and interference caused by a large number of high-order harmonics generated by the output voltage at the switching frequency and its integer multiples, and optimize the NVH performance.

[0039] The technical solution of the embodiment of the present application is to solve the above technical problems, and the overall idea is as follows:

[0040] A synchronous electric drive NVH optimization method includes: during vehicle operation, obtaining a reference frequency of a vehicle motor and determining whether the reference frequency is in a preset variable carrier frequency region; if so, randomly generating a first random number, and determining a random carrier frequency based on the first random number, the reference frequency, and a set amplitude of carrier frequency change; determining a first loading slope of the carrier in the first half cycle and a second loading slope of the carrier in the second half cycle within a current carrier cycle based on the first random number, the random carrier frequency, and a set carrier amplitude, to obtain a first carrier; comparing the first carrier with a first modulation wave, and outputting an optimized PWM signal, wherein the first modulation wave is generated based on the first carrier.

[0041] In order to better understand the above technical solution, the above technical solution will be described in detail below with reference to the accompanying drawings and specific implementation methods.

[0042] In the first aspect, an embodiment of the present invention provides a synchronous electric drive NVH optimization method, specifically, as follows Figure 1 As shown, the method includes the following steps S101 to S104:

[0043] Step S101 : During vehicle operation, a reference frequency of a vehicle motor is obtained, and it is determined whether the reference frequency is within a preset variable carrier frequency region.

[0044] It should be noted that the motor may be a permanent magnet synchronous motor, the variable carrier frequency region refers to a region where the carrier frequency changes with the rotational speed, and the fixed carrier frequency region refers to a region where the carrier frequency remains constant with changes in the rotational speed.

[0045] In a specific implementation process, obtaining the reference frequency of the vehicle motor may include: obtaining the vehicle motor speed Vm; and determining the motor reference frequency f0 according to the motor speed.

[0046] As an embodiment, the motor's reference frequency is determined by looking up a preset relationship table based on the motor speed. The preset relationship table includes a correspondence between the motor speed and the reference frequency. Specifically, the preset relationship table can be established using the formula f0 = f1 + k·S(i), where f1 is the fixed carrier frequency corresponding to the variable carrier frequency region, k is the linear slope of the variable carrier frequency, which is calibrated based on the speed range, and S(i) is the motor speed.

[0047] In a specific embodiment, the reference frequency can be obtained based on the test control console test. Considering the NVH performance in different speed segments of the permanent magnet synchronous motor, the switching frequencies in different speed segments are calibrated to obtain the optimal switching frequency (i.e., the reference frequency) in the calibrated speed segment.

[0048] For example, when the motor speed is 0-100rpm, the reference frequency is 7-8kHz; when the motor speed is 100rpm-300rpm, the reference frequency is 8-9kHz; when the motor speed is 300rpm-500rpm, the reference frequency is 9-10kHz; when the motor speed is 500rpm-700rpm, the reference frequency is 10-11kHz.

[0049] In another optional embodiment, obtaining the reference frequency of the vehicle motor may further include: obtaining the vehicle motor speed Vm and the motor torque Te; and determining the motor reference frequency based on the motor speed and torque. Specifically, the motor reference frequency may be determined by querying a preset relationship table based on the motor speed and motor torque, wherein the preset relationship table includes a correspondence between the motor speed, the motor torque, and the reference frequency.

[0050] Step S102: If the reference frequency is in the preset variable carrier frequency range, a first random number is randomly generated, and a random carrier frequency is determined according to the first random number, the reference frequency, and the amplitude of the set carrier frequency change.

[0051] In a specific embodiment, the randomly generating the first random number R1(j) may include: randomly generating the first random number R1(j) by a linear congruential method.

[0052] The linear congruential method is: R j+1 =A×R j +B%M(j=0,1,2……), where R j is the value at the current moment j, R j+1 is the value at time j+1, M is a large prime number, and A and B are set constants. The first random number R is obtained by this method. j For example, the parameters of the linear congruential method are set to A=2053, B=13849, and M=6×5536. The formula a for generating the first random number is RandomNum=(RandomNum×2053+13849)%65536. The result of calculating the remainder through the formula is a random number between 0 and 65536.

[0053] In a specific embodiment, determining the random carrier frequency according to the first random number, the reference frequency and the amplitude of the set carrier frequency change may include: s1=f0+R1(j)·Δf, to determine the random carrier frequency, where f0 is the reference frequency, R1(j) is the first randomly generated random number, and Δf is the amplitude of the carrier frequency change. Since the reference frequency f0 is in the variable carrier frequency region, f0 changes linearly with the motor speed, and the amplitude of the carrier frequency change Δf is adjusted according to the distribution of the harmonic spectrum at the actual switching frequency (i.e., the carrier frequency). For example, in this application, the value range of Δf is (0-2) kHz, with values ​​taken every 0.5 kHz.

[0054] Specifically, by combining the above formula a and formula b, the converted random carrier frequency TRpwm formula can be obtained: TRpwm = (RandomNum × Δf) / 2 16 , where RandomNum is the first random number generated randomly, and the result of the random carrier frequency is between 0 and Δf.

[0055] Step S103, determining a first carrier loading slope of the first half of the current carrier cycle and a second carrier loading slope of the second half of the current carrier cycle according to the first random number, the random carrier frequency, and the set carrier amplitude, to obtain a first carrier;

[0056] Step S104 : comparing the first carrier wave with a first modulation wave, and outputting an optimized PWM signal, where the first modulation wave is generated according to the first carrier wave.

[0057] It should be noted that the first loading slope K1 of the carrier in the first half of the current carrier cycle is: the rate at which the carrier is loaded to the maximum amplitude in the first half of the carrier cycle, and the second loading slope K2 of the carrier in the second half of the carrier cycle is: the rate at which the carrier decreases from the maximum amplitude to 0.

[0058] Determining a first carrier loading slope K1 for the first half of the current carrier cycle and a second carrier loading slope K2 for the second half of the current carrier cycle according to the first random number, the random carrier frequency, and the set carrier amplitude may include using the following formula:

[0059]

[0060] Where v is the set carrier amplitude, R1(j) is the generated random number, T s1 The carrier period is obtained by obtaining K1 and K2, and then determining the first carrier based on the current carrier frequency, the target carrier frequency, K1, and K2. The target carrier frequency is the carrier frequency position to be reached next time. The current carrier frequency and the target carrier frequency can be determined based on the rotational speed.

[0061] The first carrier wave is compared with the first modulation wave to control the on and off of the power switch (such as IGBT), thereby generating the required PWM waveform and outputting an optimized PWM signal. The first modulation wave can be generated according to the first carrier wave, that is, the amplitude of the modulation signal varies with the amplitude of the carrier signal. The first modulation wave is the waveform desired to be output.

[0062] If the carrier frequency is in the fixed carrier frequency area, a second random number is randomly generated; based on the second random number, the fixed carrier period and the set carrier amplitude, the third loading slope K3 of the carrier in the first half cycle and the fourth loading slope K4 of the carrier in the second half cycle within the carrier period of the fixed carrier frequency area are determined to obtain the second carrier, where the fixed carrier period is determined according to the carrier frequency; the second carrier is compared with the second modulation wave, and the optimized PWM signal is output, and the second modulation wave is generated according to the second carrier.

[0063] The method for randomly generating the second random number is the same as the method for randomly generating the first random number. Randomly generating the second random number may include: randomly generating the second random number R2(j) by a linear congruential method.

[0064] In a specific embodiment, according to the second random number, the fixed carrier period and the set carrier amplitude, determining the first half cycle carrier third loading slope and the second half cycle carrier fourth loading slope within the fixed carrier frequency region carrier period may include: according to the following formula

[0065]

[0066] Where v is the set carrier amplitude, R2(j) is the second random number generated randomly, T s2 The carrier period in the fixed carrier frequency region is equal to the corresponding carrier period T(j). K3 and K4 are obtained, and then the second carrier is determined based on the current carrier frequency, K3 and K4.

[0067] The second carrier wave is compared with the second modulation wave to output an optimized PWM signal. The second modulation wave is generated based on the second carrier wave. Outputting the optimized PWM signal to drive the motor can effectively reduce the motor's NVH vibration noise and achieve optimized synchronous electric drive NVH.

[0068] Furthermore, in order to better improve the noise problem, after outputting the optimized PWM signal, it can also include: obtaining six non-zero vectors and two zero vectors in the three-phase voltage space vector of the vehicle motor, the six non-zero vectors and the two zero vectors forming a hexagonal structure containing six sectors; obtaining a reference voltage vector in the sector based on two adjacent non-zero vectors and two zero vectors, and for the reference voltage vector in each sector, based on the sector where the reference voltage vector is located, determining the action time of the two adjacent non-zero vectors and the action time of the two zero vectors in each sector; randomly adjusting the action time of the two zero vectors to obtain the adjusted action time of the two zero vectors, wherein the sum of the adjusted action time of the two zero vectors remains unchanged; determining the vector switching point corresponding to each sector based on the adjusted action time of the two zero vectors and the action time of the two adjacent non-zero vectors in each sector, and generating an SVPWM modulation waveform.

[0069] In a specific embodiment, the three-phase voltage space vector of the motor forms a hexagon of a switch state space, and the hexagon is divided into six equal sectors. The six sectors include eight space vectors. The eight space vectors are obtained by eight state conversions generated by six switches in the three-phase bridge inverter circuit. The eight space vectors include six non-zero vectors and two zero vectors. The six non-zero vectors serve as boundaries of the six sectors, and the two zero vectors are at the center of the hexagon. According to the two adjacent non-zero vectors and the two zero vectors in the sector, a reference voltage vector at any position in the sector is obtained, and for the reference voltage vector in each sector, the reference voltage vector is transformed to a preset α-β axis system to obtain the first action time and the second action time of the two adjacent non-zero vectors in each sector.

[0070] Choosing a random frequency range that is too narrow limits the distribution of PWM harmonic energy, resulting in less effective PWM harmonic suppression and less than expected noise reduction. Choosing a random frequency range that is too wide can lead to unstable system control and the possibility of PWM harmonics spreading to lower frequencies. Therefore, the randomly variable carrier frequency can only be adjusted within a limited random width, which may limit the effectiveness of some NVH suppression. Based on this, a random SVPWM adjustment mechanism is proposed to further optimize motor NVH.

[0071] In a specific embodiment, the motor phase voltage can be expressed as a space vector:

[0072]

[0073] Among them, V a (t), V b (t), V c (t) is a three-phase sinusoidal voltage vector with the same amplitude and frequency and a phase difference of ±120°.

[0074] like Figure 2 As shown, the pole voltage value in the three-phase bridge inverter circuit is V dc / 2 or -V dc / 2, for example: when switches S1, S6, and S2 are all closed, the corresponding pole voltage is V ao =V dc / 2, V bo =-V dc / 2, V co =-V dc / 2, according to formula (3.9), the state corresponding to the switch closing at this time can be expressed as (100), and the space vector is The other vectors can be derived in the same way. The opening and closing control of the six switches in the three-phase bridge inverter circuit can correspond to eight states, namely: (000), (001), (010), (011), (100), (101), (110), (111). The eight states generated by the six switches control the three-phase inverter, and the eight states can be converted into eight space vectors (V0~V7) accordingly.

[0075] like Figure 3 As shown, the entire space is divided into six equal sectors, each sector is 60°, the boundaries of each sector are two non-zero vectors (including V1, V2, V3, V4, V5 and V6), V0 and V7 are two zero vectors, located at the center of the hexagon.

[0076] In one embodiment, based on two adjacent non-zero vectors and two zero vectors in a sector, a reference voltage vector at any position in the sector can be obtained by the volt-second balance principle.

[0077] Specifically, the reference voltage vector V ref It can be synthesized by two adjacent non-zero vectors and two zero vectors in the sector. For example, Figure 4 As shown, assuming V ref Located in the first sector, V ref It can be synthesized by two adjacent non-zero vectors (that is, valid vectors) V4 and V6 to obtain:

[0078]

[0079] Conclusion

[0080]

[0081] Wherein, T is the switching period of the switch, T1 is the time when the inverter operates in state (100), and T2 is the time when the inverter operates in state (110).

[0082] The reference voltage vector V refTransform to the preset α-β axis system (including α axis voltage and β axis voltage), and obtain the first action time and the second action time of two adjacent non-zero vectors in the sector, specifically including: ref Transformed to the preset α-β axis system, we can get:

[0083]

[0084] Solving equation (3.11) yields

[0085]

[0086] Get the first action time T1 of V4 and the second action time T2 of V6 in the sector, where V α is the α-axis voltage, V β The β-axis voltage is the voltage of the α-β axis, and the preset α-β axis system can be pre-set. Using this method, T1 and T2 of each sector can be obtained.

[0087] like Figure 5 As shown, the present application adopts a seven-segment symmetrical combination method, so that when the switch vector is converted, the switch state of one and only one bridge arm will change. For example, when the switch vector is converted from V0 to V1, only the state (000) is converted to (100), and only the switch states of S1 and S4 located on one bridge arm are changed; when the switch vector is converted from V1 to V2, only the state (100) is converted to (110), and only the switch states of S3 and S6 located on one bridge arm are changed; when the switch vector is converted from V2 to V7, only the state (110) is converted to (111), and only the switch states of S5 and S2 located on one bridge arm are changed.

[0088] In order to calculate the abc three-phase voltage space vector switching point T in each sector cm1 、T cm2 、T cm3 , assuming V ref Located in the first sector, let the intermediate variables be T a 、T b 、T c , according to the PWM modulation principle:

[0089]

[0090] Among them, T=T0+T1+T2, converted to

[0091]

[0092] Get the switching point T of the three-phase voltage space vector abc in the first sector cm1 、T cm2 、Tcm3 For the reference voltage vectors in other sectors, the intermediate variables are obtained based on the same method, and the voltage space vector switching point formula is used to obtain the abc three-phase voltage space vector switching point in each sector.

[0093] For example, if Figure 2 、 3 As shown, for the second sector II, the process of switching the power switches using the vector switching point is as follows: adjusting the on and off of the six switches so that the state generated by the six switches is (000), then adjusting the on and off of switches S3 and S6 so that the state generated by the six switches is (010), adjusting the on and off of switches S1 and S4 so that the state generated by the six switches is (110), and adjusting the on and off of switches S5 and S2 so that the state generated by the six switches is (111).

[0094] From the above analysis, it can be obtained that for conventional SVPWM, the action time of the two zero vectors (U0(000) and U7(111)) is equal, and the two equally divide the zero vector time.

[0095] In order to improve the problem of current concentration near the carrier frequency and its integer multiples, the harmonic components in the current change in real time, and the PWM harmonics are dispersed to a larger frequency range. The action time and setting coefficients of the two zero vectors are brought into the preset relationship model, and the setting coefficients are randomly adjusted to obtain the adjusted action time of the two zero vectors.

[0096] Specifically, this application adopts the method of establishing a relationship model between the setting coefficient r and the action time of two zero vectors, and then randomly adjusting the setting coefficient r so that the sum of the action time of the two zero vectors after adjustment remains unchanged, and obtaining the action time of each of the two zero vectors after random adjustment. Specifically, by defining a setting coefficient r, it satisfies:

[0097]

[0098] Among them, T0 is the total action time of the two zero vectors, is the action time of one of the zero vectors, is the action time of another zero vector. Figure 5 As shown, The action time is The action time is When r=1, the zero vector is entirely realized by U0; ​​when r=0, the zero vector is entirely realized by U7; when r=0.5, the zero vector is composed of U0 and U7 divided equally.

[0099] Set r to change in real time according to a certain sequence, so that the action time of U0 and U7 changes randomly, and realize the function of random SVPWM. The formula for generating random number r is:

[0100] R j+1 =(A×R j +B)%M(j=0,1,2...)(3.15)

[0101] Get a random number R j+1 , that is, r, r is greater than or equal to 0 and less than or equal to 1. Following the change of r, the action time T0 of U0 and the action time T7 of U7 change randomly, and the sum of the action time of U0 and U7 is always T0. j is the value at the current moment j, R j+1 is the value at time j+1, M is a large prime number, and A and B are set constants. For example, the adjusted U0 action time is U7 action time is adjusted accordingly

[0102] During each switching cycle, the random number r is inserted to randomly vary the durations of U0 and U7. Based on the randomly adjusted durations of the two zero vectors and the first and second durations of two adjacent non-zero vectors within each sector, the vector switching points are determined to generate the SVPWM modulation waveform. This controls the on and off of the switches, resulting in NVH optimization around the switching frequency and its multiples. This ensures that the harmonic components in the current vary in real time, rather than being concentrated around a few frequencies.

[0103] In order to more intuitively reflect the NVH optimization effect brought by the random SVPWM strategy, in an application scenario, the motor operating frequency is set to 66.66Hz and the fixed carrier frequency is 10k. The fixed carrier frequency control strategy is compared with the random variable carrier frequency + random SVPWM strategy. The simulation verification results are as follows: Figure 6 、 7 As shown, the horizontal axis represents frequency and the vertical axis represents harmonic content. It can be seen from the data that with constant carrier frequency control, the harmonic content is mainly concentrated near the open-tube frequency and its multiples, especially near 10k. The harmonic content is most obvious, that is, Figure 6 As shown in the figure, through random carrier frequency + random SVPWM optimization, it can be seen that the harmonic content around 10k is significantly reduced and the peak frequency almost disappears, that is, Figure 7 As shown in Figure 2, it can be seen that the random SVPWM strategy can better optimize the NVH performance.

[0104] In a specific embodiment, before determining the random carrier frequency, harmonic injection is also included to optimize the magnitude of the harmonic current of the permanent magnet motor.

[0105] Specifically, when the motor is powered by an inverter, the stator current contains a large number of time harmonics, which in turn generate a large number of harmonics in the air gap magnetic field. These high-order harmonics in the input current can cause electromagnetic noise. Ignoring eddy current and hysteresis losses, and assuming a saturated permanent magnet synchronous motor (PMSM) with a rotor field oriented in the shafting, the steady-state motor voltage equation is:

[0106]

[0107] Among them, u d is the d-axis voltage, u q is the q-axis voltage, i d is the d-axis current, i q is the q-axis current, L d is the d-axis inductance, L q is the q-axis inductance, R1 is the stator winding, ψ f is the permanent magnet flux, and ω is the rotor electrical angular velocity.

[0108] It should be noted that, by performing Clark transformation based on the three-phase current values ​​Ia, ib, and ic, the αβ-axis currents iα and iβ can be obtained, and by performing Park transformation based on iα and iβ, the dq-axis feedback currents id and iq can be obtained.

[0109] Rewrite Equation (3.1) as

[0110]

[0111] The terms in this equation only contain the fundamental DC component. However, in practice, the distortion of the phase current, phase voltage, and electromotive force waveforms caused by the air gap magnetic field distortion of the motor, as well as the nonlinearity of the power switching devices, must be considered. Therefore, the above equation must contain harmonic components of the 5th, 7th, 11th, and 13th orders when transformed to the rotating dq-axis coordinate system.

[0112] The three-phase voltage equation considering harmonics is:

[0113]

[0114] Among them, 5ω and 11ω are the rotation speeds of the 5th and 11th harmonic voltage vectors in the ABC coordinate system, and their rotation directions are opposite to the rotation direction of the fundamental voltage vector. 7ω and 13ω are the rotation speeds of the 7th and 13th harmonic voltage vectors, and their rotation directions are the same as the rotation direction of the fundamental voltage vector. Assume that the initial phase angles of the 5th, 7th, 11th, and 13th harmonic voltages in the fundamental voltage and PMSM phase voltage are θ1, θ2, θ3, θ4, and θ5, respectively, and the phase voltage amplitudes are u1, u5, u7, and u 11 、u 13 .

[0115] According to the principle of power conservation, the coordinate transformation of equation (3.3) is carried out from the ABC coordinate system to the dq rotating coordinate system, and we can obtain:

[0116]

[0117] Where u d1 、u q1 These are the d-axis and q-axis components of the fundamental voltage in the fundamental dq coordinate system. As can be seen from the equations, the harmonic components, when transformed from the stationary ABC axis system to the fundamental dq axis system, generally exhibit the 6th harmonic and its integer multiples.

[0118] The voltages of the 6th harmonic and integer multiples of the 6th harmonic are suppressed by using open-loop harmonic voltage injection. The following describes the process of open-loop harmonic voltage injection:

[0119] In a specific embodiment, before obtaining the vehicle's reference frequency, it may also include: obtaining the vehicle's motor acceleration, torque and motor electrical angle; determining the open-loop injected harmonic dq-axis voltage based on the motor acceleration, torque and a preset N-th two-dimensional open-loop voltage table, and performing angle conversion according to the motor electrical angle and the preset N-th harmonic to obtain the N-th harmonic electrical angle, wherein the preset N-th two-dimensional open-loop voltage table includes the correspondence between the motor acceleration, torque and the open-loop injected harmonic dq-axis voltage; performing an inverse park transform on the open-loop injected harmonic dq-axis voltage and the N-th harmonic electrical angle to obtain the α-axis voltage component and the β-axis voltage component required for the N-th harmonic injection; superimposing the α-axis voltage component with the α-axis fundamental voltage component, and superimposing the β-axis voltage component with the β-axis fundamental voltage component to obtain the superimposed α-axis voltage output and the superimposed β-axis voltage output.

[0120] In a specific embodiment, the preset Nth order two-dimensional open-loop voltmeter can be obtained by the following steps: using a test control console to perform Nth order open-loop injection harmonic dq-axis voltage calibration on the motor to establish an Nth order two-dimensional open-loop voltmeter, wherein the Nth order is 5th, 7th, 11th or 13th order.

[0121] As an example, Figure 8 As shown, the test control console rack may include: a motor controller, a motor to be tested, a host computer, a high-voltage power supply, a dynamometer, a power analyzer, and noise test equipment.

[0122] In a specific embodiment, a test control rack is used to perform N-th order open-loop injection harmonic dq-axis voltage calibration on the motor to establish an N-th order two-dimensional open-loop voltage table, which may include: obtaining the harmonic injection voltage under the given torque T0 according to the given speed, given torque T0, injected N-th order harmonic voltage amplitude U0 and dq-axis distribution current angle θ0 input by the test control rack; adjusting the magnitude of the given torque to obtain the harmonic injection voltage under different given torques, and forming a one-dimensional lookup table of torque and harmonic injection voltage;

[0123] For different given torques, the acceleration is adjusted. After each adjustment, the noise level is obtained and the voltage level U at which the noise is the smallest is determined. 11 and the angle θ 11 , according to θ 11 with U 11 , calibrate the corresponding torque and harmonic voltage under motor acceleration to form a two-dimensional table.

[0124] Specifically, according to the given speed, given torque T0, injected Nth harmonic voltage amplitude U0 and dq axis distribution current angle θ0 input by the test control frame, the harmonic injection voltage under the given torque is obtained, which may include: according to the given speed, given torque T0, injected Nth harmonic voltage amplitude U0 and dq axis distribution current angle θ0 input by the test control frame, calculating the corresponding injected Nth dq axis voltage of the dq axis; adjusting the size of θ0 according to the preset angle step, and after each adjustment, obtaining the noise size, determining θ0 when the noise is minimum, recording it as the dq axis distribution current target angle θ1, and using the angle point θ1 as the corresponding harmonic compensation point; continuing to adjust the size of U0, and after each adjustment, obtaining the noise size, determining U0 when the noise is minimum, recording it as the injected Nth harmonic voltage target amplitude U1; obtaining the harmonic injection voltage under the given torque according to θ1 and U1.

[0125] Specifically, a pure open-loop control method is used for the entire harmonic injection speed range. Taking the fifth harmonic voltage calibration as an example, the specific implementation is as follows:

[0126] The given speed of the test control frame is 3000 rpm, the given torque is T0, the amplitude of the injected fifth harmonic voltage is U0, the dq axis distribution current angle is θ0, and the calculated fifth dq axis harmonic voltage is:

[0127]

[0128] 2) Adjust θ0 according to the preset angle step size. At each angle, use a professional NVH analyzer to obtain the corresponding noise level. When the angle is adjusted to a certain value θ1, the noise level is minimized, indicating that the angle point θ1 is the corresponding harmonic compensation point. The preset angle step size U0 can be between 5° and 8°. When approaching the target value, the step size can be gradually reduced.

[0129] 3) On this basis, adjust the value of U0 and observe the noise level of the NVH analyzer. When the noise reaches the optimal value, record the voltage value as U1. The harmonic injection voltage value under the torque T0 is obtained as:

[0130]

[0131] The adjustment size of U0 does not exceed 5% of the rated voltage. The specific step size can be adjusted by 0.5V or 1V. When approaching the target value, the step size can be reduced.

[0132] 4) Similarly, given a torque value T1, follow steps 1-3 above to obtain the optimal harmonic injection voltage at the torque point T1.

[0133] 5) Under different torque levels, the test console is calibrated to form a one-dimensional lookup table of torque and fifth harmonic voltage;

[0134] 6) Expand the one-dimensional table into a two-dimensional table. The coordinates of the other dimension are the motor acceleration ACC. The data is filled with one-dimensional table data by default.

[0135] 7) Under different torques, adjust the acceleration ACC from small to large, calibrate the harmonic voltage under the corresponding torque and acceleration ACC, observe the noise level of the NVH analyzer, and when the noise reaches the optimal level, record the voltage as U 11 and angle θ 11 Here, the steady-state data obtained in steps 1 to 6 is dynamically adjusted to accommodate NVH optimization of the three-phase current harmonics during steady-state operation and dynamic operation. The torque can be adjusted from minimum to maximum torque, where the maximum and minimum torques are determined by the motor design.

[0136] 8) Finally, a two-dimensional harmonic voltage U with different torque and motor acceleration ACC is formed d5 with U q5 , a two-dimensional open-loop voltmeter is established.

[0137] In actual control, Figure 9 As shown, the following processing is performed: During the operation of the motor, according to the torque, motor acceleration and two-dimensional open-loop voltage table, the U d5 with Uq5 , where the two-dimensional open-loop voltmeter is obtained through calibration of the test console rack;

[0138] Input the rotor electrical angle θ, and perform angle conversion for the 5th harmonic to obtain the fifth harmonic electrical angle -5θ. For different harmonics, the harmonic electrical angle corresponding to the harmonic order will be obtained;

[0139] U d5 with U q5 Under the action of the fifth harmonic electrical angle -5θ, Ipark transformation is performed to obtain the α-axis voltage component U required for the fifth harmonic injection α5 and the β-axis voltage component U β5 ;

[0140] α-axis voltage component U α5 Superimposed on the α-axis fundamental voltage component Uα, the β-axis voltage component U β5 The final voltage output is obtained by superimposing it on the β-axis fundamental voltage component Uβ. The α-axis voltage and β-axis voltage obtained here can be used to calculate the space vector action time in the sector.

[0141] The following table lists the d-axis open-loop voltage Ud5 injection data for five times of actual vehicle verification for a new energy EV model, as shown in Table 1:

[0142] Table 1

[0143]

[0144] Furthermore, before performing inverse park transformation on the open-loop injected harmonic dq axis voltage and the Nth harmonic electrical angle, the method may further include: determining whether the motor speed is greater than or equal to a preset speed value; if the motor speed is greater than or equal to the preset speed value, setting the open-loop injected harmonic dq axis voltage to zero and performing inverse park transformation on the open-loop injected harmonic dq axis voltage and the Nth harmonic electrical angle; and if the motor speed is less than the preset speed value, directly performing inverse park transformation on the open-loop injected harmonic dq axis voltage and the Nth harmonic electrical angle. The preset speed value may be 4500 rpm.

[0145] like Figure 10As shown, it is a flow chart of the NVH optimization method provided by the present application, where Ia, ib, and ic are three-phase current sampling, and θ is the rotor electrical angle obtained by rotational transformation; iα and iβ are αβ-axis currents, and id and iq are dq-axis feedback currents; T0 is the given torque, MotorSpd is the motor speed, and Udc is the bus voltage; idref and iqref are the given dq-axis currents, and the feedback current id and the given current idref are PI-adjusted to obtain Ud, and the feedback current iq and the given current iqref are PI-adjusted to obtain Uq, where Ud and Uq are dq-axis voltages; MotorACC is the motor acceleration, and according to the motor acceleration and torque, through a two-dimensional voltage harmonic lookup table, it is assumed that Ud5 and Uq5 are obtained, and Ud5 and Uq5 are fifth-order harmonic dq-axis voltages. The open-loop injected harmonic dq-axis voltage and the Nth-order harmonic electrical angle are subjected to inverse park transformation to obtain the α-axis voltage component Uα and the β-axis voltage component Uβ required for Nth-order harmonic injection, and Uα and Uβ are αβ-axis voltages. Random variable carrier frequency calculation is performed according to the motor speed and torque, and finally 6 PWM signals are output; then random SVPWM is executed according to the αβ axis voltage to generate SVPWM modulation waveform.

[0146] The optimization method provided in this application includes: step 1, calibrating the 5th, 7th, 11th, or 13th order open-loop injected harmonic dq-axis voltage of a permanent magnet motor using a test console, using the noise value detected by the noise detection device as the standard, to form a two-dimensional table of motor acceleration, execution torque T0, and 5th / 7th / 11th / 13th order open-loop injected harmonic dq-axis voltage; step 2, integrating the aforementioned two-dimensional open-loop voltage table into the controller software and running the process to suppress the NVH generated by the 5th / 7th / 11th / 13th order current; step 3, integrating a random carrier frequency variable function into the software to form a function that uses the fundamental frequency carrier as the standard to achieve random width variation around it; step 4, integrating a random SVPWM wave generation function into the software to form a random variation in the distribution time of the voltage 0 vector and the voltage 7 vector. By combining steps 3 and 4, the purpose of randomly varying the controller switching tube frequency is achieved, and the purpose of suppressing the switching tube noise of the motor controller is achieved.

[0147] Therefore, by improving the software harmonic injection, optimizing the size of the 5th / 7th / 11th / 13th harmonic current of the permanent magnet motor, and using random variable carrier frequency and random SVPWM wave generation, the action characteristics of the switching frequency of the switching tube are optimized. The three software strategies of improved software harmonic injection, random variable carrier frequency and random SVPWM wave generation are combined to better suppress the NVH of the permanent magnet motor, and synchronously optimize the NVH effects of the motor and controller, so that the NVH of the electric drive assembly meets the requirements, and the comfort and driving experience of the whole vehicle are improved.

[0148] In summary, the control method for randomly adjusting the PWM carrier slope of a motor controller, proposed in this application, effectively addresses the problem of high-order harmonics in the output voltage at the switching frequency and its integer multiples, which generate significant electromagnetic noise and interference. This method allows the inverter's carrier frequency to vary according to a random function, dispersing PWM harmonics originally concentrated near the carrier frequency and its integer multiples over a wider frequency range, thereby achieving the goal of suppressing PWM harmonics and improving noise. This method involves only software strategy optimization and does not involve hardware changes or costs, making it easy to quickly implement in projects and applicable to all synchronous and asynchronous electric drive platforms.

[0149] In the second aspect, based on the same inventive concept, this embodiment provides a synchronous electric drive NVH optimization device, such as Figure 11 Shown, including:

[0150] The acquisition module 401 is used to obtain the reference frequency of the vehicle motor during vehicle operation and determine whether the reference frequency is within a preset variable carrier frequency range;

[0151] A random carrier frequency determination module 402 is configured to randomly generate a first random number if the reference frequency is within a preset variable carrier frequency region, and determine a random carrier frequency based on the first random number, the reference frequency, and a set amplitude of carrier frequency variation;

[0152] A first carrier determination module 403 is configured to determine a first carrier loading slope of a first half-cycle of the carrier and a second carrier loading slope of a second half-cycle of the carrier in a current carrier cycle according to the first random number, the random carrier frequency, and a set carrier amplitude, to obtain a first carrier;

[0153] The first optimization module 404 is configured to compare the first carrier wave with a first modulation wave, and output an optimized PWM signal, where the first modulation wave is generated according to the first carrier wave.

[0154] As an optional embodiment, the device further includes:

[0155] A second random number generating module, configured to randomly generate a second random number if the carrier frequency is in a fixed carrier frequency region;

[0156] A second carrier determination module is configured to determine, based on a second random number, a fixed carrier period, and a set carrier amplitude, a third loading slope of the carrier in the first half of the carrier period and a fourth loading slope of the carrier in the second half of the carrier period within the fixed carrier frequency region, to obtain a second carrier, wherein the fixed carrier period is determined according to the carrier frequency;

[0157] The second optimization module is used to compare the second carrier wave with the second modulation wave and output an optimized PWM signal, where the second modulation wave is generated according to the second carrier wave.

[0158] As an optional embodiment, the random carrier frequency determination module 402 is specifically configured to randomly generate a first random number by using a linear congruential method.

[0159] As an optional embodiment, the device also includes: a vector switching point determination module, used to obtain six non-zero vectors and two zero vectors in the three-phase voltage space vector of the vehicle motor, the six non-zero vectors and the two zero vectors forming a hexagonal structure containing six sectors; based on the two adjacent non-zero vectors and the two zero vectors, obtain the reference voltage vector in the sector, and for the reference voltage vector in each sector, based on the sector where the reference voltage vector is located, determine the action time of the two adjacent non-zero vectors and the action time of the two zero vectors in each sector; randomly adjust the action time of the two zero vectors to obtain the adjusted action time of each of the two zero vectors, wherein the sum of the adjusted action times of the two zero vectors remains unchanged; based on the adjusted action time of the two zero vectors and the action time of the two adjacent non-zero vectors in each sector, determine the vector switching point corresponding to each sector to generate an SVPWM modulation waveform.

[0160] As an optional embodiment, the vector switching point determination module is specifically used to: bring the action time and setting coefficient of the two zero vectors into a preset relationship model, randomly adjust the setting coefficient so that the sum of the action time of the two zero vectors after adjustment remains unchanged, and obtain the action time of each of the two zero vectors after adjustment.

[0161] As an optional embodiment, the device also includes: a harmonic injection module for obtaining the vehicle motor acceleration, torque and motor electrical angle; determining the open-loop injected harmonic dq axis voltage based on the motor acceleration, torque and a preset N-th two-dimensional open-loop voltage table, and performing angle conversion according to the motor electrical angle and the preset N-th harmonic to obtain the N-th harmonic electrical angle, wherein the preset N-th two-dimensional open-loop voltage table includes the correspondence between the motor acceleration, torque and the open-loop injected harmonic dq axis voltage; performing an inverse park transformation on the open-loop injected harmonic dq axis voltage and the N-th harmonic electrical angle to obtain the α-axis voltage component and the β-axis voltage component required for the N-th harmonic injection; superimposing the α-axis voltage component with the α-axis fundamental voltage component, and superimposing the β-axis voltage component with the β-axis fundamental voltage component to obtain the superimposed α-axis voltage output and the superimposed β-axis voltage output.

[0162] As an optional embodiment, the preset Nth order two-dimensional open-loop voltmeter is obtained by the following steps: using a test control console to perform Nth order open-loop injection harmonic dq-axis voltage calibration on the motor to establish an Nth order two-dimensional open-loop voltmeter, where Nth order is 5th order, 7th order, 11th order or 13th order.

[0163] The above modules can be implemented by software codes, in which case the above modules can be stored in the memory of the control device. The above modules can also be implemented by hardware such as integrated circuit chips.

[0164] The embodiment of the present invention provides a synchronous electric drive NVH optimization device, the implementation principle and technical effects of which are the same as those of the aforementioned method embodiment. For the sake of brief description, for matters not mentioned in the device embodiment, reference can be made to the corresponding content in the aforementioned method embodiment.

[0165] In a third aspect, based on the same inventive concept, this embodiment provides an electronic device 500, such as Figure 12 As shown, it includes: a memory 501, a processor 502 and a computer program 503 stored in the memory and executable on the processor. When the processor 502 executes the program, the steps of the synchronous electric drive NVH optimization method described in the first aspect are implemented.

[0166] Since the electronic device introduced in this embodiment is the electronic device used to implement the synchronous electric drive NVH optimization method in the embodiment of this application, based on the synchronous electric drive NVH optimization method introduced in the embodiment of this application, those skilled in the art can understand the specific implementation of the electronic device of this embodiment and its various variations, so how the electronic device implements the method in the embodiment of this application will not be described in detail here. As long as those skilled in the art implement the electronic device used in the synchronous electric drive NVH optimization method in the embodiment of this application, it falls within the scope of protection of this application.

[0167] It will be understood by those skilled in the art that embodiments of the present invention may be provided as methods, systems, or computer program products. Thus, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0168] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowcharts and / or block diagrams, as well as combinations of processes and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowcharts and / or block diagrams. Figure 1 a process or multiple processes and / or boxes Figure 1A module that specifies functions in one or more boxes.

[0169] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction module, which is implemented in the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0170] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0171] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0172] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A synchronous electric drive NVH optimization method, characterized in that: include: During the operation of the vehicle, a reference frequency of the vehicle motor is obtained, and it is determined whether the reference frequency is in a preset variable carrier frequency region; If yes, randomly generate a first random number, and determine a random carrier frequency according to the first random number, the reference frequency, and the amplitude of the set carrier frequency change; Determine a first carrier loading slope of a first half-cycle carrier and a second carrier loading slope of a second half-cycle carrier in a current carrier cycle according to the first random number, the random carrier frequency, and the set carrier amplitude, and obtain a first carrier; The first carrier wave is compared with a first modulation wave, and an optimized PWM signal is output, wherein the first modulation wave is generated according to the first carrier wave.

2. The method according to claim 1, characterized in that Also includes: If the carrier frequency is in a fixed carrier frequency region, randomly generating a second random number; According to the second random number, the fixed carrier period and the set carrier amplitude, a third loading slope of the carrier in the first half period and a fourth loading slope of the carrier in the second half period in the carrier period of the fixed carrier frequency region are determined to obtain a second carrier, wherein the fixed carrier period is determined according to the carrier frequency; The second carrier wave is compared with a second modulation wave, and an optimized PWM signal is output, wherein the second modulation wave is generated according to the second carrier wave.

3. The method according to claim 1, characterized in that The randomly generating a first random number comprises: A first random number is randomly generated by a linear congruential method.

4. The method according to claim 1, characterized in that After outputting the optimized PWM signal, the method further comprises: Acquire six non-zero vectors and two zero vectors in the three-phase voltage space vector of the vehicle motor, wherein the six non-zero vectors and the two zero vectors form a hexagonal structure including six sectors; According to two adjacent non-zero vectors and two zero vectors, a reference voltage vector in a sector is obtained, and for the reference voltage vector in each sector, based on the sector where the reference voltage vector is located, the action time of two adjacent non-zero vectors and the action time of two zero vectors in each sector are determined; Randomly adjusting the action time of the two zero vectors to obtain the respective action time of the two zero vectors after adjustment, wherein the sum of the action time of the two zero vectors after adjustment remains unchanged; According to the action time of the two adjusted zero vectors and the action time of the two adjacent non-zero vectors in each sector, the vector switching point corresponding to each sector is determined to generate an SVPWM modulation waveform.

5. The method according to claim 4, characterized in that The randomly adjusting the action time of the two zero vectors to obtain the adjusted action time of each of the two zero vectors includes: The action time and setting coefficient of the two zero vectors are brought into the preset relationship model, and the setting coefficient is randomly adjusted to obtain the respective action time of the two zero vectors after adjustment.

6. The method according to claim 1, characterized in that Before obtaining the reference frequency of the vehicle motor, the method further includes: Obtain vehicle motor acceleration, torque and motor electrical angle; Based on the motor acceleration, the torque and a preset N-order two-dimensional open-loop voltage table, an open-loop injected harmonic dq axis voltage is determined, and an angle conversion is performed according to the motor electrical angle and the preset N-order harmonic to obtain the N-order harmonic electrical angle, wherein the preset N-order two-dimensional open-loop voltage table includes a correspondence between the motor acceleration, the torque and the open-loop injected harmonic dq axis voltage; Performing an inverse park transformation on the open-loop injected harmonic dq axis voltage and the Nth harmonic electrical angle to obtain an α-axis voltage component and a β-axis voltage component required for Nth harmonic injection; The α-axis voltage component is superimposed on the α-axis fundamental voltage component, and the β-axis voltage component is superimposed on the β-axis fundamental voltage component to obtain a superimposed α-axis voltage output and a superimposed β-axis voltage output.

7. The method according to claim 6, characterized in that The preset N-times two-dimensional open-loop voltage table is obtained by the following steps: The test control frame is used to perform N-order open-loop injection harmonic dq-axis voltage calibration on the motor, and an N-order two-dimensional open-loop voltage table is established, wherein the N-order is 5th, 7th, 11th or 13th.

8. A synchronous electric drive NVH optimization device, characterized in that: include: An acquisition module, used to acquire a reference frequency of a motor of a vehicle during operation of the vehicle, and to determine whether the reference frequency is within a preset variable carrier frequency region; A random carrier frequency determination module, configured to randomly generate a first random number if the reference frequency is in a preset variable carrier frequency region, and determine a random carrier frequency according to the first random number, the reference frequency, and a set amplitude of carrier frequency change; A first carrier determination module, configured to determine a first carrier loading slope of a first half-cycle carrier and a second carrier loading slope of a second half-cycle carrier in a current carrier cycle according to the first random number, the random carrier frequency and a set carrier amplitude, to obtain a first carrier; The first optimization module is used to compare the first carrier with a first modulation wave and output an optimized PWM signal, wherein the first modulation wave is generated according to the first carrier.

9. An electronic device, characterized in that: include: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the method according to any one of claims 1 to 7 when executing the program.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the steps of the method described in any one of claims 1 to 7 are implemented.

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