A random frequency conversion control method for NVH of a motor controller in a pure electric vehicle

Abstract

This invention provides a random frequency conversion control method for NVH (Noise, Vibration, and Harshness) of a motor controller in a pure electric vehicle. The method includes: simulating the full throttle pedal condition of the entire vehicle on an electric drive test bench to eliminate tire noise and wind noise interference, thereby obtaining a spectrum diagram of the NVH of the electric drive system at the IGBT base frequency under the full throttle pedal condition; analyzing the spectrum diagram to identify the prominent NVH noise range under the full throttle pedal condition, and using this prominent NVH noise range as the entry condition for random frequency conversion; establishing corresponding random frequency conversion models for different prominent NVH noise ranges based on the base frequency of the IGBT switching frequency, to perform random frequency conversion control on the prominent NVH noise ranges, and using the base frequency of the IGBT switching frequency for control in the non-prominent noise ranges. This invention can reduce the switching frequency noise of the motor controller and improve the NVH performance and safety of electric vehicles.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of NVH control of electric vehicles, in particular to a motor controller NVH random frequency conversion control method of a pure electric vehicle. BACKGROUND

[0002] With the advancement of electrification, the NVH (Noise, Vibration, Harshness) of electric vehicles, i.e. noise, vibration and smoothness quality, is increasingly concerned. Poor NVH quality will reduce the subjective driving experience of the driver. Compared with traditional internal combustion engine vehicles, the NVH problem of electric vehicles is more prominent in some aspects due to their own low damping and high speed characteristics. In particular, the pure electric vehicle is equipped with a motor controller, which has a power switching device. The switching frequency of this device on the pure electric vehicle is generally 5-10KHz. The high-frequency noise brought by high switching frequency will make people uncomfortable. In the existing pure electric vehicle, the IGBT switching frequency noise in the motor controller is generally suppressed by frequency folding control, i.e. using segmented IGBT switching frequency when the motor controller high-frequency noise is poor to avoid the IGBT high-frequency noise poor area. At the moment when the IGBT noise is poor, directly changing the switching frequency base frequency has two problems: 1. Directly changing the switching frequency does not consider the efficiency. Only adjusting the IGBT switching frequency, the motor controller efficiency is lower. Only adjusting the low switching frequency, the current waveform sinusoidal degree in this time period is affected. 2. Due to the difference in consistency of the motor controller production, the noise may not be concentrated at the base frequency, but may be concentrated at other frequency bands. Simply changing the IGBT switching frequency cannot solve the IGBT high-frequency noise problem 100%. Therefore, how to control the switching frequency of the motor controller has important significance. SUMMARY

[0003] The present application provides a motor controller NVH random frequency conversion control method of a pure electric vehicle, which solves the switching frequency noise control of the motor controller of the existing electric vehicle, easily causes the problem of efficiency and reliability of the motor controller, can reduce the switching frequency noise of the motor controller, and improve the NVH performance and safety of the electric vehicle.

[0004] To achieve the above purpose, the present application provides the following technical scheme:

[0005] A motor controller NVH random frequency conversion control method of a pure electric vehicle, comprising:

[0006] Simulate the full throttle pedal condition of the whole vehicle on the electric drive bench, exclude the noise interference of the tire noise and wind noise in the whole vehicle, and obtain the frequency spectrum diagram of the NVH of the electric drive system at the IGBT base frequency under the full throttle pedal condition;

[0007] According to the spectrum analysis, a NVH noise prominent interval under a full throttle pedal working condition is analyzed, and the NVH noise prominent interval is taken as an entering condition of NVH random frequency conversion;

[0008] According to a base frequency of an IGBT switching frequency, a corresponding NVH random frequency conversion model is established for different NVH noise prominent intervals, so as to perform random frequency conversion control on the NVH noise prominent intervals, and a base frequency of an IGBT switching frequency is used for control in a noise non-prominent interval.

[0009] Preferably, the NVH random frequency conversion model is established, including:

[0010] Different NVH noise prominent intervals are calibrated to different NVH random frequency conversion models K1, K2, …, Kn, where Kn=T(f±△fn), n is a natural number, T is a frequency conversion period, the value interval is 100us-1s, and different intervals correspond to different frequency conversion periods, f is a base frequency of an IGBT switching frequency, and△fn is a frequency change range of the corresponding interval.

[0011] Preferably, the NVH random frequency conversion model is established, including:

[0012] A random number is generated by using a random number generation function, and the randomly generated number is symmetric around the base frequency f.

[0013] Preferably, the NVH random frequency conversion model is established, including:

[0014] The IGBT switching frequency is controlled to be randomly changed symmetrically before and after the base frequency f, so that the value of the random frequency conversion is normally distributed at the base frequency f, and the center point is the base frequency f.

[0015] Preferably, it further includes:

[0016] A corresponding table of motor speed, output torque and the NVH noise prominent interval is established;

[0017] The speed and output torque of the motor during the running of the whole vehicle are obtained, and the corresponding NVH noise prominent interval is determined through the corresponding table, so as to perform NVH random frequency conversion control.

[0018] Preferably, it further includes:

[0019] It is judged whether the motor speed is 2000-12000 rpm and the output torque is 0-175 NM, if yes, the frequency conversion period and the frequency change range of the IGBT switching are determined through the corresponding table, so as to perform NVH random frequency conversion control, otherwise, the base frequency of the IGBT switching frequency is used for control.

[0020] Preferably, the NVH noise prominent interval under the full throttle pedal working condition analyzed according to the spectrum diagram comprises:

[0021] When the NVH noise in the spectrum diagram exceeds 80dB, it is the NVH noise prominent interval, interval 1 is N1, interval 2 is N2, and interval n is Nn.

[0022] Preferably, the base frequency of the IGBT switching frequency is f=10K, and the frequency conversion period T=500us.

[0023] The application provides a motor controller NVH random frequency conversion control method of a pure electric vehicle, establishes a corresponding NVH random frequency conversion model for the NVH noise prominent interval through the spectrum diagram of the NVH noise under the IGBT base frequency, and performs random frequency conversion control, solves the switching frequency noise control of the motor controller of the existing electric vehicle, and solves the problem that the efficiency and reliability of the motor controller are easily reduced, can reduce the switching frequency noise of the motor controller, and improves the NVH performance and safety of the electric vehicle. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to more clearly illustrate the specific embodiments of the application, the following will briefly introduce the drawings needed to be used in the embodiments.

[0025] Figure 1 A motor controller NVH random frequency conversion control method of a pure electric vehicle provided by the application is shown in the figure.

[0026] Figure 2 A motor controller NVH random frequency conversion control logic flowchart of a pure electric vehicle provided by the embodiment of the application is shown in the figure. DETAILED DESCRIPTION

[0027] In order to make the personnel in the technical field better understand the scheme of the embodiment of the application, the following will further specifically describe the embodiment of the application in combination with the drawings and the embodiments.

[0028] In order to make the personnel in the technical field better understand the scheme of the embodiment of the application, the following will further specifically describe the embodiment of the application in combination with the drawings and the embodiments.

[0029] As shown in the figure, a motor controller NVH random frequency conversion control method of a pure electric vehicle comprises: Figure 1

[0030] ​S1: Simulate the full throttle pedal condition of the whole vehicle on the electric drive bench, exclude the noise interference of tire noise and wind noise in the whole vehicle, and obtain the frequency spectrum of the electric drive system under the IGBT base frequency NVH in the full throttle pedal condition.

[0031] S2: According to the frequency spectrum, analyze the NVH noise prominent interval under the full throttle pedal condition, and take the NVH noise prominent interval as the entering condition of the NVH random frequency variation.

[0032] S3: According to the base frequency of the IGBT switching frequency, different NVH noise prominent intervals are established corresponding NVH random frequency variation model, to control the random frequency variation of the NVH noise prominent interval, and the base frequency of the IGBT switching frequency is used for control in the noise non prominent interval.

[0033] Specifically, the full throttle pedal condition WOT full power output condition of the whole vehicle is simulated by the bench, the vehicle controller VCU receives the throttle pedal instruction to give the torque instruction of the motor controller, the bench independently controls the motor to output the current maximum torque through the motor controller, the frequency spectrum of the motor controller NVH under the IGBT base frequency is collected, and the NVH noise prominent interval N1, N2……Nn of the whole vehicle under the WOT condition is obtained; The speed, torque or power condition of the entering of the NVH random frequency variation is determined according to the noise prominent interval; Different random frequency variation models K1, K2……Kn are calibrated in different noise intervals based on the bench; The corresponding random frequency variation model K1, K2……Kn is injected in the corresponding noise interval N1, N2……Nn, and the motor is controlled by frequency variation. This method can avoid the high frequency noise caused by IGBT, and improve the NVH performance and safety of electric vehicle.

[0034] Further, the NVH random frequency variation model is established, including: different NVH noise prominent intervals are calibrated to different NVH random frequency variation models K1, K2……Kn, wherein Kn=T(f±△fn), n is a natural number, T is a frequency variation period, the value interval is 100us-1s, and different intervals correspond to different frequency variation periods, f is the base frequency of the IGBT switching frequency, and△fn is the change range of the corresponding interval frequency.

[0035] Specifically, the model K in different random frequency variation models K1, K2……Kn is K, and the expression of K is Kn=T(f±△fn). The frequency variation period T in different random frequency variation models K is different, which can be generally selected in the interval of 100us-1s; In the noise prominent range, the IGBT switching frequency randomly changes between f±△f. In order to ensure that the efficiency of the motor controller is not affected, the IGBT switching frequency must be randomly changed symmetrically around the base frequency f, and the center point is the base frequency f.

[0036] Further, the NVH random frequency conversion model is established, and further comprising: generating random numbers by using a random number generating function, and making the randomly generated numbers symmetric around the base frequency f.

[0037] Further, the NVH random frequency conversion model is established, and further comprising: generating random numbers by using a random number generating function, and making the randomly generated numbers symmetric around the base frequency f.

[0038] The method further comprises:

[0039] A corresponding table of motor speed, output torque and the NVH noise prominent interval is established.

[0040] The motor speed and output torque during the running of the whole vehicle are obtained, and the corresponding NVH noise prominent interval is determined through the corresponding table to perform NVH random frequency conversion control.

[0041] In actual application, the motor speed and output torque corresponding to the NVH noise prominent interval are calibrated through bench test, and a one-to-one corresponding table is formed. During the running of the whole vehicle, the corresponding NVH noise prominent interval is obtained by table lookup through the corresponding table according to the obtained motor speed and output torque, and then the corresponding random frequency conversion model is obtained to perform NVH random frequency conversion control.

[0042] The method further comprises: determining whether the motor speed is 2000-12000 rpm and the output torque is 0-175 NM, and if so, determining the frequency conversion period and the frequency change range of the IGBT switch through the corresponding table to perform NVH random frequency conversion control, otherwise, the base frequency of the IGBT switch frequency is controlled.

[0043] Further, the NVH noise prominent interval under the full throttle pedal working condition is analyzed according to the frequency spectrum, comprising: when the NVH noise in the frequency spectrum exceeds 80 dB, it is the NVH noise prominent interval, interval 1 is N1, interval 2 is N2, …, interval n is Nn.

[0044] Further, the base frequency of the IGBT switch frequency is f=10K, and the frequency conversion period T=500us.

[0045] In an embodiment, the motor is simulated to pull full throttle from 0 to the highest speed on the bench, and the NVH frequency spectrum is obtained. The points with higher NVH sound pressure level are found out to inject the random frequency conversion model. The control logic of the random frequency conversion model is as follows: Figure 2As shown, when the whole vehicle is running, whether the NVH noise of the vehicle is in a low frequency range is judged through the motor speed and torque, if yes, the base frequency of the IGBT switching frequency is used for control, if not, the variable frequency period of the IGBT switching frequency is obtained through table lookup, and the amplitude limiting processing is carried out with the base frequency f as the center, and then the random variable frequency control is carried out according to the NVH random variable frequency model, different IGBT switching frequency settings can be realized by setting the mark position of the IGBT switching frequency, and the IGBT is driven by the PWM wave to work at the above-mentioned switching frequency.

[0046] It can be seen that the present application provides a motor controller NVH random variable frequency control method of a pure electric vehicle, the corresponding NVH random variable frequency model is established for the NVH noise prominent interval through the NVH frequency spectrum diagram under the IGBT base frequency, so as to carry out random variable frequency control, solve the switching frequency noise control of the motor controller of the existing electric vehicle, and solve the problem that the efficiency and reliability of the motor controller are easily reduced, the switching frequency noise of the motor controller can be reduced, and the NVH performance and safety of the electric vehicle are improved.

[0047] The above describes the structure, features and effect of the present application in detail according to the embodiment shown in the drawing, the above is only the preferred embodiment of the present application, but the present application is not limited to the embodiment shown in the drawing, any change or modification made according to the idea of the present application, or the equivalent embodiment of equivalent change, as long as it does not exceed the spirit of the specification and the drawing, should be within the protection scope of the present application.

Claims

1. A method for NVH random frequency control of a motor controller of a pure electric vehicle, characterized in that, The method comprises the following steps: In the electric drive bench simulation of the whole oil pedal condition of the vehicle, the noise interference of the tire noise and the wind noise in the vehicle is excluded to obtain the frequency spectrum of the NVH of the electric drive system under the IGBT base frequency in the whole oil pedal condition; According to the frequency spectrum, the NVH noise prominent interval under the whole oil pedal condition is analyzed, and the NVH noise prominent interval is taken as the entering condition of the NVH random frequency conversion; According to the noise prominent interval, the speed, torque or power conditions of the entering of the NVH random frequency conversion are determined; According to the base frequency of the IGBT switching frequency, the corresponding NVH random frequency conversion model is established for different NVH noise prominent intervals, the corresponding random frequency conversion model is injected into the NVH noise prominent interval, the random frequency conversion control is performed on the NVH noise prominent interval, and the base frequency of the IGBT switching frequency is used for control in the noise non-prominent interval; A corresponding table of the motor speed, output torque and the NVH noise prominent interval is established; The speed and output torque of the motor during the operation of the vehicle are obtained, and the corresponding NVH noise prominent interval is determined through the corresponding table to perform the NVH random frequency conversion control; The NVH random frequency conversion model is established, which comprises: Different NVH noise prominent intervals are calibrated to different NVH random frequency conversion models K1, K2……Kn, wherein n is a natural number, T is a frequency conversion period, the value interval is 100us~1s, and different intervals correspond to different frequency conversion periods, f is the base frequency of the IGBT switching frequency, and △fn is the frequency change range of the corresponding interval.

2. The method of claim 1, wherein the method further comprises: The NVH random frequency conversion model is also established, which comprises: A random number is generated by using a random number generation function, and the randomly generated number is symmetric around the base frequency f.

3. The method of claim 2, wherein the method further comprises: The NVH random frequency conversion control comprises: The IGBT switching frequency is controlled to be randomly changed symmetrically before and after the base frequency f, so that the value of the random frequency conversion is in a normal distribution around the base frequency f, and the center point is the base frequency f.

4. The method of claim 3, wherein the method further comprises: The method further comprises: It is judged whether the motor speed is 2000~12000rpm and the output torque is 0~175NM, if yes, the frequency conversion period and the frequency change range of the IGBT switching are determined through the corresponding table to perform the NVH random frequency conversion control, otherwise, the base frequency of the IGBT switching frequency is used for control.

5. The method of claim 4, wherein the method further comprises: The NVH noise prominent interval under the whole oil pedal condition is analyzed according to the frequency spectrum, which comprises: When the NVH noise in the frequency spectrum is more than 80dB, it is the NVH noise prominent interval, interval 1 is N1, interval 2 is N2,……interval n is Nn.

6. The method of claim 5, wherein the method further comprises: The base frequency of the IGBT switching frequency is f=10K, and the frequency conversion period T=500us.

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