CN108068659A - A kind of method, apparatus and system for inhibiting electric vehicle shake - Google Patents

Abstract

This application discloses a kind of method, apparatus and system for inhibiting electric vehicle shake, for inhibiting electric vehicle shake, improve driver comfort.This method includes：Obtain the tach signal of motor；Fourier analysis is carried out to the tach signal, obtains the frequency and amplitude of the active constituent that rotating speed is caused to be shaken in the tach signal；The rotating speed is dithered as between electric vehicle drag torque and the moment of resistance that there are shakes caused by non-linear relation；The parameter for inhibiting rotating speed and shaking is obtained according to the frequency of the active constituent that rotating speed is caused to be shaken and amplitude；The parameter and the tach signal shaken according to the inhibition rotating speed obtain compensation torque by differential inertial element and bandpass filtering link；The compensation torque is overlapped with given torque, to inhibit to rotating speed shake.Due to inhibiting the shake of electric vehicle, reduce the mechanical resonance generated during shake, and then reduce the abrasion of electric vehicle hardware.

Description

Method, device and system for inhibiting electric vehicle shaking

Technical Field

The application relates to the technical field of electric automobiles, in particular to a method, a device and a system for inhibiting electric automobile shaking.

Background

The electric automobile has the advantages of high efficiency, energy conservation, low noise, zero emission and the like, so the electric automobile is a development trend of new energy automobiles in the future. Along with the gradual improvement of environmental protection consciousness of people, electric automobile receives people's favor more and more.

The electric automobile usually adopts the reduction gear to replace the gearbox of traditional car, adopts spline connection between motor and the reduction gear, passes through the universal joint between reduction gear and the wheel and connects. Because certain connecting clearance and flexibility exist among the spline, the speed reducer and the universal joint.

The instant jump of the motor output torque in the starting process of the electric automobile can cause the elastic deformation of a transmission system, and the nonlinear relation exists between the traction torque and the resistance torque, so that the rotating speed is jittered. In addition, under some conditions of high-speed operation, mechanical resonance can occur in a vehicle power transmission system, and output torque fluctuation of a motor can be caused, so that rotating speed jitter is caused.

The problem of rotational speed jitter not only seriously affects the driving comfort of the electric automobile, but also reduces the working performance and service life of the transmission system.

Therefore, how to restrain the problem of the rotating speed jitter of the electric automobile and slow down the jitter of the whole automobile becomes a problem to be solved urgently in the field of motor driving.

Disclosure of Invention

The application provides a method, a device and a system for inhibiting the shaking of an electric automobile, which can effectively inhibit the shaking of the rotating speed of the electric automobile, thereby improving the driving comfort and simultaneously improving the working performance and the service life of a transmission system.

In a first aspect, a method for suppressing electric vehicle judder is provided, the method comprising:

acquiring a rotating speed signal of a motor;

carrying out Fourier analysis on the rotating speed signal to obtain the frequency and amplitude of an effective component causing rotating speed jitter in the rotating speed signal; the rotating speed jitter is jitter caused by a nonlinear relation between the traction torque and the resisting torque of the electric automobile;

obtaining a parameter for inhibiting the rotation speed jitter according to the frequency and the amplitude of the effective component causing the rotation speed jitter;

obtaining a compensation torque through a differential inertia link and a band-pass filtering link according to the parameter for inhibiting the rotating speed jitter and the rotating speed signal;

and superposing the compensation torque and the given torque to suppress the rotation speed jitter.

In a first possible implementation manner of the first aspect, performing fourier analysis on the rotation speed signal to obtain a frequency and an amplitude of an effective component causing rotation speed jitter in the rotation speed signal specifically includes:

carrying out Fourier analysis on the rotating speed signal to obtain the amplitude of each component in the rotating speed signal;

taking the component with the maximum amplitude as an effective component causing the rotation speed jitter;

and obtaining the frequency and the amplitude of the effective component causing the rotation speed jitter.

With reference to the first aspect and any one of the foregoing possible implementation manners, in a second possible implementation manner, the method further includes the step of superimposing the compensation torque and the given torque, and the step of:

carrying out amplitude limiting on the compensation torque to obtain the compensation torque after amplitude limiting;

the step of superposing the compensation torque and the given torque comprises the following specific steps:

and superposing the limited compensation torque and the given torque.

With reference to the first aspect and any one of the foregoing possible implementation manners, in a third possible implementation manner, obtaining a compensation torque through a differential inertia link and a band-pass filtering link according to the parameter for suppressing the rotational speed jitter and the rotational speed signal specifically includes:

obtaining a compensation torque by the following transfer function;

wherein, ω is_nCenter frequency for bandpass filtering, damping coefficient, T, ξ₁Pass band gain, T, for band pass filtering₂The turning frequency of the differential inertia element; s is a laplace variable;

wherein f is₁ ^*The frequency of the effective component causing the rotation speed jitter is obtained; a. the₁ ^*The amplitude of the effective component causing the rotation speed jitter is obtained; a and b are coefficients for adjusting the on-gain and the pass-band width, respectively.

With reference to the first aspect and any one of the foregoing possible implementation manners, in a fourth possible implementation manner, obtaining a parameter for suppressing the rotational speed jitter according to the frequency and the amplitude of the effective component causing the rotational speed jitter specifically includes:

frequency f of the effective component which will cause rotational speed jitter₁ ^*And amplitude A₁ ^*Obtaining a parameter for inhibiting the rotation speed jitter through the following formula; the parameters for inhibiting the rotation speed jitter are respectively as follows: pass band gain T of band pass filter₁Turning frequency T of differential inertia element₂Center frequency omega of band-pass filter_nAnd damping coefficient ξ;

T₁＝aA₁

ω_n＝2πf₁ ^*

ξ＝b

where a and b are coefficients for adjusting the on-gain and the pass-band width, respectively.

With reference to the first aspect and any one of the foregoing possible implementation manners, in a fifth possible implementation manner, the method further includes:

obtaining a direct-axis current deviation signal and a quadrature-axis current deviation signal of the motor;

fourier analysis is respectively carried out on the motor direct-axis current deviation signal and the motor quadrature-axis current deviation signal to obtain the frequency and the amplitude of effective components causing current jitter in direct-axis current and quadrature-axis alternating current;

obtaining parameters for suppressing the current jitter according to the frequency and the amplitude of the effective component causing the current jitter;

obtaining a direct axis compensation voltage and a quadrature axis compensation voltage through a resonance control link by utilizing the parameter for inhibiting current jitter, the direct axis current deviation signal and the quadrature axis current deviation signal;

and superposing the direct axis compensation voltage and the quadrature axis compensation voltage with the output direct axis voltage and the output quadrature axis voltage respectively to inhibit current jitter.

With reference to the first aspect and any one of the foregoing possible implementation manners, in a sixth possible implementation manner, performing fourier analysis on the direct-axis current deviation signal and the quadrature-axis current deviation signal of the motor to obtain a frequency and an amplitude of an effective component causing current jitter in direct-axis current and quadrature-axis alternating current respectively, specifically includes:

respectively carrying out Fourier analysis on the direct-axis current deviation signal and the quadrature-axis current deviation signal to respectively obtain the amplitude of each component in the direct-axis current deviation signal and the quadrature-axis current deviation signal;

taking the component with the maximum amplitude as an effective component causing current jitter;

and obtaining the frequency and the amplitude of effective components causing current jitter in the direct-axis current and the quadrature-axis alternating current.

With reference to the first aspect and any one of the foregoing possible implementation manners, in a seventh possible implementation manner, the superimposing the direct axis compensation voltage and the quadrature axis compensation voltage on the output direct axis voltage and the output quadrature axis voltage respectively further includes:

carrying out amplitude limiting on the direct axis compensation voltage and the quadrature axis compensation voltage to obtain an amplitude-limited direct axis compensation voltage and an amplitude-limited quadrature axis compensation voltage;

and superposing the direct axis compensation voltage and the quadrature axis compensation voltage with the output direct axis voltage and the output quadrature axis voltage respectively, specifically:

and superposing the direct axis compensation voltage after amplitude limiting and the quadrature axis compensation voltage after amplitude limiting with the output direct axis voltage and the output quadrature axis voltage respectively.

With reference to the first aspect and any one of the foregoing possible implementation manners, in an eighth possible implementation manner, obtaining a direct axis compensation voltage and a quadrature axis compensation voltage through a resonance control link by using the parameter for suppressing current jitter, the direct axis current deviation signal, and the quadrature axis current deviation signal specifically includes:

obtaining a direct axis compensation voltage and a quadrature axis compensation voltage through the following transfer functions;

wherein, ω is_cA predetermined bandwidth, omega, for said resonant control link₀Is the center frequency, k is the gain, c is the preset coefficient for adjusting the gain; omega₀＝2πf₂ ^*，k＝c·A₂ ^*；f₂ ^*The frequency of the effective component causing the current jitter; a. the₂ ^*Is the amplitude of the effective component causing current jitter; s is the Laplace variable.

In a second aspect, an apparatus for suppressing electric vehicle judder is provided, the apparatus comprising:

the acquisition unit is used for acquiring a rotating speed signal of the motor;

the rotating speed jitter effective component obtaining unit is used for carrying out Fourier analysis on the rotating speed signal to obtain the frequency and the amplitude of an effective component causing rotating speed jitter in the rotating speed signal; the rotating speed jitter is jitter caused by a nonlinear relation between the traction torque and the resisting torque of the electric automobile;

the rotation speed jitter suppression parameter obtaining unit is used for obtaining a rotation speed jitter suppression parameter according to the frequency and the amplitude of the effective component causing rotation speed jitter;

the compensation torque obtaining unit is used for obtaining compensation torque through a differential inertia link and a band-pass filtering link according to the parameter for inhibiting the rotating speed jitter and the rotating speed signal;

and the rotational speed jitter suppression unit is used for superposing the compensation torque and given torque so as to suppress the rotational speed jitter.

In a first possible implementation manner of the second aspect, the rotational speed jitter effective component obtaining unit includes:

the rotating speed signal component obtaining subunit is used for carrying out Fourier analysis on the rotating speed signal to obtain the amplitude of each component in the rotating speed signal;

a rotational speed jitter effective component obtaining subunit, configured to take the component with the largest amplitude as an effective component causing rotational speed jitter;

and the frequency and amplitude first obtaining subunit is used for obtaining the frequency and amplitude of the effective component causing the rotating speed jitter.

With reference to the second aspect and any one of the foregoing possible implementation manners, in a second possible implementation manner, the method further includes: a torque limiter unit;

the torque amplitude limiting unit is used for carrying out amplitude limiting on the compensation torque to obtain the compensation torque after amplitude limiting;

and the rotating speed jitter suppression unit is used for superposing the limited compensation torque and the given torque.

With reference to the second aspect and any one of the foregoing possible implementation manners, in a third possible implementation manner, the method further includes:

the current deviation signal obtaining unit is used for obtaining a direct-axis current deviation signal and a quadrature-axis current deviation signal of the motor;

the current jitter effective component obtaining unit is used for respectively carrying out Fourier analysis on the direct-axis current deviation signal and the quadrature-axis current deviation signal of the motor to obtain the frequency and the amplitude of an effective component causing current jitter in direct-axis current and quadrature-axis alternating current;

a current jitter suppression parameter obtaining unit for obtaining a current jitter suppression parameter from the frequency and amplitude of the effective component causing current jitter;

the compensation voltage obtaining unit is used for obtaining direct axis compensation voltage and quadrature axis compensation voltage through a resonance control link by utilizing the parameter for inhibiting current jitter, the direct axis current deviation signal and the quadrature axis current deviation signal;

and the current jitter suppression unit is used for respectively superposing the direct axis compensation voltage and the quadrature axis compensation voltage with the output direct axis voltage and the output quadrature axis voltage so as to suppress current jitter.

With reference to the second aspect and any one of the foregoing possible implementation manners, in a fourth possible implementation manner, the current jitter effective component obtaining unit includes:

the current deviation signal component obtaining subunit is used for respectively carrying out Fourier analysis on the direct-axis current deviation signal and the quadrature-axis current deviation signal and respectively obtaining the amplitude of each component in the direct-axis current deviation signal and the quadrature-axis current deviation signal;

a current jitter effective component obtaining subunit, configured to take a component with the largest amplitude as an effective component causing current jitter;

and the frequency and amplitude second obtaining subunit is used for obtaining the frequency and amplitude of effective components causing current jitter in the direct-axis current and the quadrature-axis alternating current.

With reference to the second aspect and any one of the foregoing possible implementation manners, in a fifth possible implementation manner, the method further includes: a voltage amplitude limiting unit;

the voltage amplitude limiting unit is used for carrying out amplitude limiting on the direct axis compensation voltage and the quadrature axis compensation voltage to obtain an amplitude-limited direct axis compensation voltage and an amplitude-limited quadrature axis compensation voltage;

and the current jitter suppression unit is used for superposing the amplitude-limited direct axis compensation voltage and the amplitude-limited quadrature axis compensation voltage with the output direct axis voltage and the output quadrature axis voltage respectively.

In a third aspect, a system for suppressing electric vehicle vibration is provided, which is applied to control of a motor of an electric vehicle, and includes: a speed sensor and a motor controller;

the rotating speed sensor is used for acquiring a rotating speed signal of the motor;

the motor controller is used for carrying out Fourier analysis on the rotating speed signal to obtain the frequency and amplitude of an effective component causing rotating speed jitter in the rotating speed signal; the rotating speed jitter is jitter caused by a nonlinear relation between the traction torque and the resisting torque of the electric automobile; obtaining a parameter for inhibiting the rotation speed jitter according to the frequency and the amplitude of the effective component causing the rotation speed jitter; obtaining a compensation torque through a differential inertia link and a band-pass filtering link according to the parameter for inhibiting the rotating speed jitter and the rotating speed signal; and superposing the compensation torque and the given torque to suppress the rotation speed jitter.

In a first possible implementation manner of the third aspect, the motor controller is further configured to obtain a motor direct-axis current deviation signal and a motor quadrature-axis current deviation signal; fourier analysis is respectively carried out on the motor direct-axis current deviation signal and the motor quadrature-axis current deviation signal to obtain the frequency and the amplitude of effective components causing current jitter in direct-axis current and quadrature-axis alternating current; obtaining parameters for suppressing the current jitter according to the frequency and the amplitude of the effective component causing the current jitter; obtaining a direct axis compensation voltage and a quadrature axis compensation voltage through a resonance control link by utilizing the parameter for inhibiting current jitter, the direct axis current deviation signal and the quadrature axis current deviation signal; and superposing the direct axis compensation voltage and the quadrature axis compensation voltage with the output direct axis voltage and the output quadrature axis voltage respectively to inhibit current jitter.

According to the technical scheme, the embodiment of the application has the following advantages:

the application provides a method for restraining electric automobile shaking, the rotating speed of a motor is collected to obtain a corresponding rotating speed signal, Fourier analysis is carried out on the obtained rotating speed signal, the frequency and the amplitude of an effective component causing the rotating speed shaking in the rotating speed signal are further obtained, parameters for restraining the rotating speed shaking are obtained according to the frequency and the amplitude of the effective component causing the rotating speed shaking, compensation torque is obtained through a differential inertia link and a band-pass filtering link by utilizing the parameters for restraining the rotating speed shaking and the rotating speed signal, the compensation torque is superposed with given torque, and the restraining of the rotating speed shaking of the electric automobile can be realized.

According to the method for inhibiting the electric automobile shaking, when the working condition of the electric automobile changes, the frequency of the effective component which causes the rotating speed shaking and is obtained through Fourier analysis is different, and then the parameter for inhibiting the rotating speed shaking is obtained according to the frequency and the amplitude of the effective component and is different, so that the parameter for inhibiting the rotating speed shaking can be obtained in real time according to the working condition of the electric automobile, the working condition of the parameter for inhibiting the shaking is not required to be manually adjusted according to the current working condition of the electric automobile for self-adaption, and the adaptability of the system is enhanced. In addition, in the method provided by the application, the compensation torque needs to be obtained according to the parameters for inhibiting the rotation speed jitter and the rotation speed signal through the combined action of the differential inertia link and the band-pass filtering link, so that the problem that the direct deviation exists in the extraction of the rotation speed fluctuation quantity of the vehicle under the working condition of accelerated running is solved. In summary, the method for inhibiting the electric vehicle from shaking provided by the application can effectively inhibit the shaking of the electric vehicle, improves the driving comfort, and reduces the mechanical resonance generated during shaking due to the inhibition of the shaking of the electric vehicle, thereby reducing the abrasion of the hardware of the electric vehicle.

Drawings

FIG. 1 is a block diagram of a system for suppressing vehicle shudder;

FIG. 2 is a block diagram of another system for suppressing shudder in electric vehicles;

FIG. 3 is a flowchart of a method for suppressing electric vehicle judder according to an embodiment of the present disclosure;

FIG. 4 is a flowchart of another method for suppressing electric vehicle judder according to an embodiment of the present disclosure;

FIG. 5 is a schematic block diagram illustrating an embodiment of the present disclosure for suppressing rotational speed jitter of an electric vehicle;

FIG. 6 is a block diagram of a specific implementation of suppressing rotational speed jitter of an electric vehicle according to an embodiment of the present application;

FIG. 7 is a flowchart of a method for suppressing current jitter of an electric vehicle according to an embodiment of the present application;

FIG. 8 is a schematic block diagram of suppressing current jitter of an electric vehicle according to an embodiment of the present application;

FIG. 9 is a block diagram of a specific implementation of suppressing current jitter of an electric vehicle according to an embodiment of the present application;

FIG. 10 is a structural diagram of an apparatus for suppressing shaking of an electric vehicle according to an embodiment of the present application;

FIG. 11 is a structural diagram of another apparatus for suppressing electric vehicle judder according to an embodiment of the present application;

FIG. 12 is a structural diagram of an apparatus for suppressing current jitter of an electric vehicle according to an embodiment of the present application;

fig. 13 is a structural diagram of an apparatus for suppressing current jitter of an electric vehicle according to an embodiment of the present application;

FIG. 14 is a system configuration diagram for suppressing electric vehicle judder according to the embodiment of the present application;

fig. 15 is a schematic diagram of a system for suppressing electric vehicle judder in an embodiment of the present application.

Detailed Description

The embodiment of the application provides a method, a device and a system for inhibiting electric vehicle shaking, which are used for inhibiting the shaking of an electric vehicle, so that the driving comfort is improved, and meanwhile, the working performance and the service life of a hardware structure in an automobile transmission system can be improved.

Electric automobile takes place the shake at the in-process that traveles, will influence the travelling comfort that electric automobile drove to electric automobile's shake also can cause certain influence to some hardware structures on the electric automobile, can cause the damage to some hardware structures, and then influence its life.

As shown in fig. 1, a configuration diagram of a system for suppressing rotational speed hunting of an electric vehicle is shown. Specifically, after a Vehicle Control Unit (VCU) acquires a rotation speed signal, a deviation calculation is performed on the rotation speed signal and the given rotation speed signal, a table is looked up according to the calculated deviation amount, a Resistance Capacitance (RC) filter parameter is obtained, and the rotation speed signal is filtered according to the RC filter parameter, wherein the RC filter is a circuit which operates by using a voltage source, a current source, a resistor and a capacitor. And then according to the rotating speed signal obtained by filtering, looking up a table and calculating a Proportional Integral Derivative (PID) adjusting parameter, wherein the PID parameter is respectively a Proportional parameter, an Integral parameter and a Derivative parameter, the PID parameter is used for calculating a correction value of the torque, and the corrected torque value is issued to a controller of the generator so as to realize the function of inhibiting the rotating speed jitter.

The inventor researches and discovers that the mode for restraining the rotation speed jitter of the electric automobile corresponding to the figure 1 has the following defects:

because the speed jitter is restrained by the Vehicle Control Unit (VCU), the acquisition of the speed signal and the issuing of the torque command are both limited by the communication time of the Vehicle Control Unit (VCU) and the motor controller (IPU), a large delay is generated, the restraining effect is limited, and the speed jitter can be restrained within 90rpm/60ms generally. In addition, when the operation condition changes, the filtering parameters are obtained in a table look-up mode according to the rotating speed deviation, and the control adaptability is poor.

In addition, as shown in fig. 2, a scheme for suppressing the hunting of the electric vehicle is a configuration diagram of the system which realizes the suppression of the rotational speed hunting on the motor controller side. Specifically, the desired torque is corrected through a speed feedback link, a motor rotating speed detection link detects a rotating speed signal of the motor, the detected rotating speed signal is subjected to a low-pass filter, a motor rotating speed differential, an inertia link and output amplitude limiting to obtain a torque compensation value, and the torque compensation value is superposed on the desired torque, so that the suppression of rotating speed jitter can be realized.

In the research process of the inventor, the following defects exist in the scheme for inhibiting the rotating speed jitter of the electric automobile corresponding to the scheme shown in fig. 2:

because the values of the control parameters such as the filter coefficient and the time parameter in the speed feedback link are fixed, the jitter of a single frequency band can be effectively inhibited. In addition, under the working condition of vehicle acceleration operation, the torque compensation value is obtained by using a low-pass filter, a motor rotating speed differential link and an inertia link, so that the extracted rotating speed fluctuation quantity has a direct deviation, and a larger deviation exists between the actual given torque and the expected torque.

In summary, with the system for suppressing the rotational speed jitter of the electric vehicle corresponding to fig. 1 or fig. 2, the disadvantages of a rotational speed jitter suppression delay, limited suppression effect, poor control adaptability, capability of suppressing the torque jitter of only a single frequency band, and the like may occur, and thus the suppression of the rotational speed jitter of the electric vehicle may not be effectively realized.

The application provides a method for restraining electric automobile shaking, the rotating speed of a motor is collected to obtain a corresponding rotating speed signal, Fourier analysis is carried out on the obtained rotating speed signal, the frequency and the amplitude of an effective component causing the rotating speed shaking in the rotating speed signal are further obtained, parameters for restraining the rotating speed shaking are obtained according to the frequency and the amplitude of the effective component causing the rotating speed shaking, compensation torque is obtained through a differential inertia link and a band-pass filtering link by utilizing the parameters for restraining the rotating speed shaking and the rotating speed signal, the compensation torque is superposed with given torque, and the restraining of the rotating speed shaking of the electric automobile can be realized.

The method provided by the application can effectively inhibit the shaking of the electric automobile, so that the driving comfort is greatly improved, and in addition, the shaking of the electric automobile is inhibited, so that the mechanical resonance generated in the shaking process is reduced, and the damage to the hardware structure on the electric automobile is reduced.

Method embodiment one

Referring to fig. 3, it is a flowchart of a method for suppressing electric vehicle judder according to this embodiment. The method comprises the following steps:

step 301: and acquiring a rotating speed signal of the motor.

Specifically, when the rotating speed of the motor is collected, the rotating speed of the motor can be collected by adopting a rotating transformer and other speed sensors, after a rotating speed analog signal is obtained, the analog signal is sent to the motor controller, the motor controller converts the analog signal into a digital signal, and the digital signal is decoded to obtain a corresponding rotating speed signal.

Step 302: carrying out Fourier analysis on the rotating speed signal to obtain the frequency and amplitude of an effective component causing rotating speed jitter in the rotating speed signal; the rotation speed jitter is jitter caused by the nonlinear relation between the traction torque and the resisting torque of the electric automobile.

The essence of the fourier transform is to convert a time domain waveform into a frequency domain for decomposition, and decompose the time domain waveform into the sum of sine waves with different frequencies, so that the amplitude and phase information of each frequency component in the rotation speed signal can be detected by analyzing the rotation speed signal by using the fourier transform.

The fourier transform equation is as follows:

wherein, a₀As a direct component, A_n、f_nAndrespectively the amplitude, frequency and phase of the nth harmonic.

During specific implementation, a time domain decimation method can be selected to perform fast fourier transform on the rotating speed signal so as to implement fourier analysis on the rotating speed signal, and the formula is as follows:

wherein,the input sequence x (N) has the length of N and satisfies that N is 2^LAnd L is a positive integer.

The components of all frequencies are obtained through Fourier analysis of the rotating speed signals, and the frequency and the amplitude of effective components causing rotating speed jitter are obtained.

Step 303: and obtaining a parameter for inhibiting the rotation speed jitter according to the frequency and the amplitude of the effective component causing the rotation speed jitter.

And correspondingly calculating according to the frequency and the amplitude of the effective component causing the rotation speed jitter, which are obtained in the step 302, to obtain a parameter for suppressing the rotation speed jitter, wherein the parameter for suppressing the rotation speed jitter may specifically be a pass band gain of band-pass filtering, a turning frequency of a differential inertia element, a center frequency of the band-pass filtering, and a damping coefficient.

Step 304: and obtaining the compensation torque through a differential inertia link and a band-pass filtering link according to the parameters for inhibiting the rotating speed jitter and the rotating speed signal.

The parameters for suppressing the rotational speed jitter obtained in step 303 are corresponding parameters in the differential inertia link and the band-pass filtering link, and the compensation torque of the system can be obtained after the rotational speed signal obtained in step 301 is processed by the differential inertia link and the band-pass filtering link.

The differential link can reflect the change rate of the speed signal, and can effectively extract the fluctuation signal of the rotating speed so as to suppress the jitter. However, the result obtained by the differential operation may have a large fluctuation, and this embodiment further provides an inertia element, and the result obtained by the differential operation on the rotational speed is smoothed by the inertia element, so as to obtain a more stable result.

In addition, the rotating speed jitter signal generally contains a high-frequency component, and in the starting and accelerating process of the electric automobile, a large direct-current component also exists in the rotating speed signal after being processed by the differentiation link, so that in order to prevent the extracted rotating speed fluctuation from having a direct offset, the embodiment of the application also provides a band-pass filter which can extract an effective signal from the fluctuation signal of the rotating speed.

Step 305: the compensation torque and the given torque are superimposed to suppress the rotational speed hunting.

The compensation torque obtained in step 304 is added to the given torque, so that the suppression of the rotational speed jitter of the electric vehicle can be realized.

According to the method for inhibiting the electric vehicle from shaking, when the working condition of the electric vehicle changes, the frequencies of the effective components which cause the rotating speed shaking and are obtained through Fourier analysis are different, and further the parameters for inhibiting the rotating speed shaking are obtained according to the frequencies and the amplitudes of the effective components, so that the parameters for inhibiting the rotating speed shaking can be obtained in real time according to the working condition of the electric vehicle, the working condition of the electric vehicle for manually adjusting the parameters for inhibiting the shaking according to the current working condition of the electric vehicle is not needed to be self-adaptive, and the adaptability of the system is enhanced. In addition, in the method provided by this embodiment, a compensation torque needs to be obtained according to a parameter for suppressing rotational speed jitter and a rotational speed signal through the combined action of a differential inertia link and a band-pass filtering link, so that the problem that a direct offset exists when a rotational speed fluctuation amount is extracted under the working condition of accelerated running of a vehicle is solved. In summary, the method for inhibiting the electric vehicle from shaking provided by the application can effectively inhibit the shaking of the electric vehicle, improves the driving comfort, and reduces the mechanical resonance generated during shaking due to the inhibition of the shaking of the electric vehicle, thereby reducing the abrasion to hardware on the electric vehicle.

In practical applications, in order to facilitate implementation of the method for suppressing the electric vehicle shake in the first embodiment of the method, the present embodiment provides a more specific implementation scheme.

Method embodiment two

Referring to fig. 4, the method for suppressing electric vehicle shake provided by the embodiment includes:

step 401: and acquiring the rotating speed of the motor to obtain a corresponding rotating speed signal.

The implementation method of step 401 is the same as that of step 301 in the first embodiment of the method, and is not described herein again.

Step 402: and carrying out Fourier analysis on the rotating speed signal to obtain the amplitude of each component in the rotating speed signal.

The rotation speed signal obtained in step 401 is subjected to fourier analysis, and the essence of fourier transformation is to convert a time domain waveform into a frequency domain for decomposition into a sum of sine waves with different frequencies, so that the amplitude and phase information of each frequency component in the rotation speed signal can be detected by analyzing the rotation speed signal by using fourier transformation.

The fourier transform equation is as follows:

wherein, a₀As a direct component, A_n、f_nAndrespectively the amplitude, frequency and phase of the nth harmonic.

During specific implementation, a time domain decimation method is selected to perform fast Fourier transform on the rotating speed signal so as to realize Fourier analysis on the rotating speed signal, and the formula is as follows:

wherein,the input sequence x (N) has a length of N, and N ═ 2L is satisfied, and L is a positive integer.

Namely, Fourier analysis is carried out on the rotating speed signal to obtain components of different frequencies in the rotating speed signal, and meanwhile, the amplitude of each frequency component is obtained.

Step 403: the component with the largest amplitude is taken as an effective component causing the rotational speed jitter.

Step 404: the frequency and amplitude of the effective component causing the rotational speed jitter are obtained.

And selecting the component with the maximum amplitude from the frequency components, and taking the component as an effective component causing the rotation speed jitter. Further, the frequency and amplitude of the effective component causing the rotational speed jitter are obtained.

Step 405: the parameters for suppressing the rotational speed jitter are obtained from the frequency and amplitude of the effective component causing the rotational speed jitter.

Specifically, the frequency f of the effective component causing the rotational speed jitter acquired in step 302 is set to₁Sum amplitude A₁Input f (T)₁、T₂、ω_nξ) f (f, a) to obtain parameters for suppressing rotational speed jitter, the parameters for suppressing rotational speed jitter being the pass band gain T of the band-pass filter₁Turning frequency T of differential inertia element₂Center frequency omega of band-pass filtering_nAnd a damping coefficient ξ.

Specifically, the formula for obtaining each parameter for suppressing the rotational speed jitter is as follows:

T₁＝aA₁ ^*

ω_n＝2πf₁ ^*

ξ＝b

wherein, a and b are coefficients for adjusting the on-state gain and the pass band width, respectively, and may be set according to actual conditions, which is not specifically limited in this embodiment. For example, different vehicle models have different requirements.

Step 406: and obtaining the compensation torque by using the parameters for inhibiting the rotating speed jitter and the rotating speed signal through a differential inertia link and a band-pass filtering link.

Obtaining a compensation torque by the following transfer function;

wherein, ω is_nCenter frequency for bandpass filtering, damping coefficient, T, ξ₁Pass band gain, T, for band pass filtering₂The turning frequency of the differential inertia element; s is the Laplace variable.

During specific implementation, a differential inertia link and a band-pass filtering link may be set in the jitter suppression regulator, the rotation speed signal corresponding to the motor rotation speed acquired in step 401 is input into the jitter suppression regulator, and each parameter T for suppressing rotation speed jitter acquired in step 405 is input into the jitter suppression regulator₁、T₂、ω_nAnd ξ are also input into the jitter suppression regulator, and the rotational speed signal is subjected to differential inertia processing and band-pass filtering processing by using the parameters for suppressing rotational speed jitter to obtain compensation torque.

During specific implementation, the formula is discretized, and a differential equation of a differential inertia link and a band-pass filtering link can be obtained after discretization as follows:

wherein,

wherein, T₁、T₂、ω_nAnd ξ are the inhibitions obtained in step 303And s is a Laplace variable as a parameter of the rotating speed jitter.

Pass band gain T due to bandpass filtering₁And the damping coefficient ξ can be adjusted on line by a coefficient a and a coefficient b respectively, and the turning frequency T of the differential inertia element₂And center frequency omega of band-pass filtering_nThe frequency calculation method is obtained according to the frequency of the effective component which is obtained by Fourier analysis and causes the rotating speed jitter, so that the defect that the frequency adaptation range of a filtering scheme in the prior art is narrow is overcome, and the good filtering effect can be still kept when the rotating speed jitter is changed in a wide range.

Step 407: and carrying out amplitude limiting on the compensation torque to obtain the compensation torque after amplitude limiting.

Specifically, the compensation torque is limited within a controllable range by clipping the compensation torque according to the following formula.

Wherein, Delta T' is the torque compensation amount amplitude limiting output, Delta T is the torque compensation amount, Delta T_UpLimitFor the upper limit of the torque compensation amount, Δ T_DnLimitIs a lower limit of the torque compensation amount.

Performing amplitude limiting processing on the compensation torque obtained in step 406, specifically, replacing the value of the compensation torque with the value of the torque compensation amount upper limit when the compensation torque is greater than the torque compensation amount upper limit; when the compensation torque is between the lower limit of the torque compensation amount and the upper limit of the torque compensation amount, the value of the compensation torque is not changed; and when the compensation torque is smaller than the lower limit of the torque compensation amount, replacing the value of the compensation torque with the value of the lower limit of the torque compensation amount.

Step 408: and superposing the limited compensation torque and the given torque to suppress the speed jitter.

And superposing the compensation torque after amplitude limiting and the given torque, so that the rotation speed jitter of the electric automobile can be restrained.

The method provided by the embodiment can be implemented in the form of a rotational speed jitter suppression module, and a functional block diagram of the module is shown in fig. 5.

As shown in fig. 5, fourier analysis of the acquired rotation speed signal n is implemented in the form of an FFT unit, and the frequency f of the effective component causing the rotation speed jitter is obtained by fourier analysis of the rotation speed signal₁ ^*And amplitude A₁ ^*The frequency f of the effective component causing the rotational speed jitter₁ ^*And amplitude A₁ ^*An input parameter adaptation unit which adapts the frequency f of the effective component causing the rotational speed jitter₁ ^*And amplitude A₁ ^*Obtaining a parameter T for suppressing the rotational speed jitter₁、T₂、ω_nξ, the parameters for suppressing the rotational speed jitter are all parameters in the transfer function in the speed jitter suppression regulator, the rotational speed signal is processed by the transfer function in the speed jitter suppression regulator to obtain the compensation torque delta T, the compensation torque delta T is output and limited, namely the compensation torque delta T can be superposed with the given torque to realize the suppression of the rotational speed jitter of the electric automobile, and fig. 6 is a block diagram of a specific implementation corresponding to fig. 5.

The method for suppressing the shaking of the electric vehicle provided by the embodiment is embodied by the method for suppressing the shaking of the electric vehicle provided by the embodiment, that is, a more specific method is provided for realizing the suppression of the shaking of the rotating speed of the electric vehicle. The method provided by the implementation can effectively inhibit the rotation speed jitter of the electric automobile, improves the driving comfort, and reduces the mechanical resonance generated during jitter due to the inhibition of the jitter of the electric automobile, thereby reducing the abrasion to hardware on the electric automobile.

When electric automobile work was in the high-frequency range, the shake of easy emergence electric current, the current shake can make the torque take place the shake, can influence the travelling comfort that electric automobile drove equally to can cause certain harm to the inside hardware structure of electric automobile. In order to further ensure that the shaking of the electric vehicle is suppressed, the embodiment further provides a current shaking suppressing method, and on the basis of the method for suppressing the shaking of the rotating speed provided in the first method embodiment, the suppression of the current shaking is further increased, so as to achieve a better shaking suppressing effect on the electric vehicle.

It should be noted that the current jitter suppression method and the rotational speed jitter suppression method provided in the first embodiment of the method provided in this embodiment are two independent methods, and the order of use of the two methods is not fixed.

Method embodiment three

Referring to fig. 7, a flow chart of a method for suppressing increased current jitter based on the rotational speed jitter suppressing method is shown.

Step 701: and obtaining a direct-axis current deviation signal and a quadrature-axis current deviation signal of the motor.

Specifically, the direct-axis current deviation signal and the quadrature-axis current deviation signal of the motor may be acquired by a current sensor such as a hall element.

Step 702: fourier analysis is respectively carried out on the direct-axis current deviation signal and the quadrature-axis current deviation signal of the motor to obtain the frequency and the amplitude of effective components causing current jitter in the direct-axis current and the quadrature-axis current.

And respectively carrying out Fourier analysis on the direct-axis current deviation signal and the quadrature-axis current deviation signal to respectively obtain the amplitude of each component in the direct-axis current deviation signal and the quadrature-axis current deviation signal.

The component with the largest amplitude is taken as the effective component causing current jitter.

The frequency and amplitude of the effective components in the direct-axis current and quadrature-axis current that cause current jitter are obtained.

In specific implementation, the fourier analysis of the direct-axis current deviation signal and the quadrature-axis current deviation signal can be implemented in the form of an FFT unit. The essence of the Fourier transform is to convert a time domain waveform into a frequency domain for decomposition, and decompose the time domain waveform into the sum of sine waves with different frequencies, so that the amplitude and phase information of each frequency component in the motor direct-axis current deviation signal and the motor quadrature-axis current deviation signal can be detected by analyzing the motor direct-axis current deviation signal and the motor quadrature-axis current deviation signal by using the Fourier transform method.

Wherein, a₀As a direct component, A_n、f_n、The amplitude, frequency and phase of the nth harmonic.

During specific implementation, a time domain decimation method is selected to perform fast Fourier transform on the direct-axis current deviation signal and the quadrature-axis current deviation signal of the motor so as to realize Fourier analysis on the direct-axis current deviation signal and the quadrature-axis current deviation signal of the motor, and the formula is as follows:

wherein,the input sequence x (N) has the length of N and satisfies that N is 2^LAnd L is a positive integer.

Screening each frequency component obtained by Fourier analysis, specifically, selecting a component with the maximum amplitude from each frequency component of the direct-axis current deviation signal as an effective component causing current jitter in the direct-axis current; and selecting the component with the largest amplitude from the frequency components of the quadrature axis current deviation signal as an effective component causing current jitter in the quadrature axis current. The frequency and the amplitude of the effective component causing the current jitter in the direct-axis current and the quadrature-axis current are respectively obtained as the frequency and the amplitude of the effective component causing the current jitter in the direct-axis current and the quadrature-axis current.

Step 703: the parameters for suppressing the current jitter are obtained from the frequency and amplitude of the effective component causing the current jitter.

In a specific implementation, the parameter for suppressing the current jitter can be obtained in the form of a parameter adaptive unit. Inputting the frequency and amplitude of the effective component which is acquired in the FFT analysis unit and causes the current jitter into f (omega) in the parameter self-adapting unit₀,k)＝f(f^*,A^*) Obtaining parameters for inhibiting current jitter, wherein the parameters for inhibiting the current jitter are respectively the central frequency omega₀And a gain k.

Specifically, the formula for obtaining the parameter for suppressing the direct-axis current jitter is as follows:

ω₀＝2πf₂ ^*

k＝a·A₂ ^*

wherein, ω is₀Is the center frequency, k is the gain, and a is the adjustment factor. f. of₂ ^*To cause the frequency of the effective component of the direct-axis current jitter, A₂ ^*The magnitude of the effective component that causes the direct axis current dither.

The formula for obtaining the parameters for suppressing the quadrature axis current jitter is as follows:

ω₀'＝2πf₃ ^*

k'＝a·A₃ ^*

wherein, ω is₀'is the center frequency, k' is the gain, and a is the adjustment factor. f. of₃ ^*To cause the frequency of the effective component of quadrature current jitter, A₃ ^*Is the magnitude of the effective component that causes quadrature current jitter.

Step 704: and obtaining direct axis compensation voltage and quadrature axis compensation voltage through a resonance control link by utilizing the parameter for inhibiting current jitter, the direct axis current deviation signal and the quadrature axis current deviation signal.

Obtaining a direct axis compensation voltage and a quadrature axis compensation voltage through the following transfer functions;

wherein, ω is_cA predetermined bandwidth, omega, for said resonant control link₀Is the center frequency, k is the gain, c is the preset coefficient for adjusting the gain; s is the Laplace variable.

In a specific implementation, a resonance control link may be set in the current jitter suppression regulator, the direct-axis current deviation signal and the quadrature-axis current deviation signal acquired in step 701 are input to the current jitter suppression regulator, and the parameters for suppressing the direct-axis current jitter and the quadrature-axis current jitter acquired in step 703 are also input to the current jitter suppression regulator. Performing resonance control processing on the direct-axis current deviation signal by using each parameter for inhibiting the direct-axis current jitter to obtain a direct-axis compensation voltage; and performing resonance control processing on the quadrature axis current deviation signal by using each parameter for inhibiting the quadrature axis current jitter to obtain a quadrature axis compensation voltage.

The resonance control link can realize zero steady state non-difference control on sinusoidal signals with the same frequency as the resonance frequency of the sinusoidal signals. During concrete implementation, a quasi-resonance controller can be adopted in the resonance control link, and when the quasi-resonance controller is adopted, the resonance control link can achieve larger gain, and the influence of fundamental frequency deviation can be effectively reduced.

The system transfer function is as follows:

during specific implementation, the system transfer function is discretized, and a difference equation of the resonance control link obtained after discretization is as follows:

wherein,D＝2ω_cT，E＝-2ω_cT。

wherein, ω is_cIs the bandwidth, ω₀Is the center frequency, k is the gain, c is the coefficient that adjusts the gain, and s is the laplace variable.

Due to the center frequency omega₀The frequency of the effective component causing the current jitter is calculated according to the Fourier analysis, so that the defect of narrow frequency adaptation range in the existing control method is overcome, and the effect of resonance control can be still maintained under the condition of wider jitter frequency.

Step 705: and respectively superposing the direct axis compensation voltage and the quadrature axis compensation voltage with the output direct axis voltage and the output quadrature axis voltage so as to inhibit current jitter.

Before the direct axis compensation voltage and the quadrature axis compensation voltage are respectively superposed with the output direct axis voltage and the output quadrature axis voltage, amplitude limiting is carried out on the direct axis compensation voltage and the quadrature axis compensation voltage, the direct axis compensation voltage after amplitude limiting and the quadrature axis compensation voltage after amplitude limiting are obtained, and the direct axis compensation voltage and the quadrature axis compensation voltage are limited in a controllable range.

The output direct-axis voltage and the output alternating-current voltage are respectively output after the direct-axis current and the quadrature-axis current are subjected to PI regulation.

Specifically, the direct axis compensation voltage and the quadrature axis compensation voltage are clipped according to the following formula, and the clipped direct axis compensation voltage and quadrature axis compensation voltage are obtained.

Wherein, the delta u' is the amplitude limiting output of the compensation voltage, the delta u is the compensation quantity of the d and q axes voltage, and the delta u_UpLimitTo compensate for the upper voltage limit, Δ u_DnLimitTo compensate for the lower voltage limit.

In concrete implementation, the direct axis compensation voltage obtained in step 704 is subjected to amplitude limiting, specifically, when the direct axis compensation voltage is greater than the upper limit of the compensation voltage, the value of the direct axis compensation voltage is replaced with the value of the upper limit of the compensation voltage; when the direct axis compensation voltage is between the lower compensation voltage limit and the upper compensation voltage limit, the value of the direct axis compensation voltage is not changed; and when the direct axis compensation voltage is smaller than the value of the lower limit of the compensation voltage, replacing the value of the direct axis compensation voltage with the value of the lower limit of the compensation voltage.

It should be noted that the method for performing amplitude limiting on the quadrature axis compensation voltage is the same as the method for performing amplitude limiting on the direct axis compensation voltage, and is not described herein again.

The direct axis compensation voltage after amplitude limiting is superposed with the output direct axis voltage, so that the direct axis current jitter can be inhibited; and superposing the quadrature axis compensation voltage after amplitude limiting with the output quadrature axis voltage to realize the suppression of the quadrature axis current jitter.

The method provided by the present embodiment may be implemented in the form of a current jitter suppression module, and a functional block diagram of the module is shown in fig. 8.

As shown in FIG. 8, the acquired direct axis current deviation signal Δ i is implemented in the form of an FFT analysis unit_dAnd quadrature axis current deviation signal Δ i_qPerforming Fourier analysis by comparing the direct-axis current deviation signal Δ i_dAnd quadrature axis current deviation signal Δ i_qFourier analysis is carried out to obtain the frequency f of effective components causing current jitter in direct-axis current and quadrature-axis current^*And amplitude A^*The frequency f of the effective component causing current jitter^*And amplitude A^*Inputting the parameter self-adapting unit, and obtaining the parameter omega for inhibiting the current jitter through the processing of the parameter self-adapting unit₀K, the parameters for inhibiting the current jitter are all parameters in the transfer function in the current jitter inhibiting regulator, and the direct-axis current deviation signal and the quadrature-axis current deviation signal are processed by the transfer function in the current jitter inhibiting regulator to obtain a direct-axis compensation voltage delta u_dQuadrature axis compensation voltage Deltau_qCompensating the direct axis for the voltage Deltau_dQuadrature axis compensation voltage Deltau_qProcessed by an output amplitude limiting unit to obtain an amplitude-limited direct axis compensation voltage delta u'_dAnd quadrature axis compensation voltage delta u'_qCorrespondingly, the direct axis compensation voltage and the quadrature axis compensation voltage after amplitude limiting are respectively superposed with the output direct axis voltage and the output quadrature axis voltage, and therefore current jitter suppression can be achieved. Fig. 9 is a block diagram of a specific implementation corresponding to fig. 8.

The method for suppressing current jitter provided by the embodiment further suppresses current jitter generated when the electric vehicle works in a high frequency band on the basis of suppressing rotation speed jitter, so that driving comfort can be guaranteed when the electric vehicle works in any frequency, and a hardware structure in the vehicle can be protected all the time.

Based on the method for suppressing the shaking of the electric vehicle introduced in the method embodiment, the embodiment of the present application further provides a device for suppressing the shaking of the electric vehicle, which is described in detail below with reference to the accompanying drawings.

Apparatus embodiment one

Referring to fig. 10, a structural diagram of an apparatus for suppressing shaking of an electric vehicle according to the present embodiment includes:

and the acquisition unit 1001 is used for acquiring the rotating speed of the motor to obtain a corresponding rotating speed signal.

The rotational speed jitter effective component obtaining unit 1002 is configured to perform fourier analysis on the rotational speed signal to obtain a frequency and an amplitude of an effective component causing rotational speed jitter in the rotational speed signal.

And a rotational speed jitter suppression parameter obtaining unit 1003 for obtaining a rotational speed jitter suppression parameter from the frequency and amplitude of the effective component causing the rotational speed jitter.

And a compensation torque obtaining unit 1004 for obtaining a compensation torque through a differential inertia element and a band-pass filtering element by using the parameter for suppressing the rotational speed jitter and the rotational speed signal.

And a rotational speed shake suppression unit 1005 for superimposing the compensation torque and the given torque to suppress rotational speed shake.

As shown in fig. 11, the rotational speed jitter effective component obtaining unit 1002 includes:

the rotation speed signal component obtaining subunit 1101 is configured to perform fourier analysis on the rotation speed signal, and obtain an amplitude of each component in the rotation speed signal.

A rotational speed shake effective component obtaining subunit 1102 is configured to take the component with the largest amplitude as the effective component causing rotational speed shake.

A frequency and amplitude first obtaining subunit 1103 configured to obtain the frequency and amplitude of the effective component causing the rotational speed jitter.

As shown in fig. 11, the apparatus further includes:

the torque limiting unit 1104 is configured to limit the compensation torque to obtain the limited compensation torque.

And a rotational speed jitter suppression unit 1005 for superimposing the limited compensation torque and the predetermined torque.

According to the device for inhibiting the electric automobile from shaking, when the working condition of the electric automobile changes, the frequencies of effective components which are obtained through Fourier analysis and cause the rotating speed shaking are different, and further the parameters for inhibiting the rotating speed shaking are obtained according to the frequencies and the amplitudes of the effective components, so that the parameters for inhibiting the rotating speed shaking can be obtained in real time according to the working condition of the electric automobile, the working condition of the electric automobile for manually adjusting the parameters for inhibiting the shaking according to the current working condition of the electric automobile is not needed to be self-adaptive, and the adaptability of the system is enhanced. In addition, in the device provided by this embodiment, compensation torque needs to be obtained according to the parameter for suppressing rotational speed jitter and the rotational speed signal through the combined action of the differential inertia link and the band-pass filtering link, so that the problem that the rotational speed fluctuation amount extracted has a direct offset when the vehicle is in an accelerated operation working condition is solved. In summary, the method for inhibiting the electric vehicle from shaking provided by the application can effectively inhibit the shaking of the electric vehicle, improves the driving comfort, and reduces the mechanical resonance generated during shaking due to the inhibition of the shaking of the electric vehicle, thereby reducing the abrasion to hardware on the electric vehicle.

Based on the method for suppressing the current jitter of the electric vehicle described in the third embodiment of the method, the third embodiment of the present invention provides a device for suppressing the current jitter of the electric vehicle on the basis of the device for suppressing the current jitter of the electric vehicle provided in the first embodiment of the device, and the following detailed description is provided with reference to the accompanying drawings.

Device embodiment II

Referring to fig. 12, a structural diagram of an apparatus for suppressing current jitter of an electric vehicle according to the present embodiment is provided on the basis of the first apparatus embodiment, and the apparatus includes:

a current deviation signal obtaining unit 1201, configured to obtain a direct-axis current deviation signal and a quadrature-axis current deviation signal of the motor.

The current jitter effective component obtaining unit 1202 is configured to perform fourier analysis on the motor direct axis current deviation signal and quadrature axis current deviation signal to obtain the frequency and amplitude of an effective component causing current jitter in the direct axis current and the quadrature axis alternating current, respectively.

A suppression current jitter parameter obtaining unit 1203 is configured to obtain a parameter for suppressing current jitter from the frequency and the amplitude of the effective component causing current jitter.

A compensation voltage obtaining unit 1204, configured to obtain a direct axis compensation voltage and a quadrature axis compensation voltage through a resonance control link by using the parameter for suppressing current jitter, the direct axis current deviation signal, and the quadrature axis current deviation signal;

a current jitter suppression unit 1205, configured to superimpose the direct-axis compensation voltage and the quadrature-axis compensation voltage with the output direct-axis voltage and the output quadrature-axis voltage, respectively, so as to suppress current jitter.

As shown in fig. 13, the current jitter effective component obtaining unit 1202 includes:

the current deviation signal component obtaining subunit 1301 is configured to perform fourier analysis on the direct-axis current deviation signal and the quadrature-axis current deviation signal, and obtain the amplitude of each component in the direct-axis current deviation signal and the quadrature-axis current deviation signal.

A current jitter effective component obtaining subunit 1302, configured to take the component with the largest amplitude as the effective component causing the current jitter.

And a frequency and amplitude second obtaining subunit 1303, configured to obtain the frequency and amplitude of the effective component of the direct-axis current and the quadrature-axis alternating current, which cause current jitter.

As shown in fig. 13, the apparatus further includes:

and a voltage amplitude limiting unit 1304, configured to perform amplitude limiting on the direct axis compensation voltage and the quadrature axis compensation voltage, so as to obtain an amplitude-limited direct axis compensation voltage and an amplitude-limited quadrature axis compensation voltage.

The current jitter suppression unit 1205 is configured to superimpose the clipped direct axis compensation voltage and the clipped quadrature axis compensation voltage with the output direct axis voltage and the output quadrature axis voltage, respectively.

The current jitter suppression device provided by the embodiment further suppresses the current jitter generated when the electric automobile works in a high frequency band on the basis of suppressing the rotation speed jitter, so that the driving comfort can be ensured when the electric automobile works in any frequency, and the hardware structure in the automobile can be protected all the time.

Based on the method and the device for suppressing the shaking of the electric vehicle, which are introduced in the embodiment of the method, the embodiment provides a system for suppressing the shaking of the electric vehicle, and the detailed description is provided below with reference to the attached drawings.

System embodiment

Referring to fig. 14, a system structure diagram for suppressing the shaking of the electric vehicle is provided in this embodiment.

And the rotating speed sensor 1401 is used for acquiring the rotating speed of the motor to obtain a corresponding rotating speed signal.

The motor controller 1402 is used for performing fourier analysis on the rotation speed signal to obtain the frequency and amplitude of an effective component causing rotation speed jitter in the rotation speed signal; obtaining a parameter for inhibiting the rotation speed jitter according to the frequency and the amplitude of the effective component causing the rotation speed jitter; obtaining a compensation torque by utilizing the parameter for inhibiting the rotating speed jitter through a differential inertia link and a band-pass filtering link; and superposing the compensation torque and the given torque to suppress the rotational speed jitter.

Specifically, a speed sensor such as a resolver may be used to measure the rotation speed of the motor, obtain an analog signal corresponding to the rotation speed of the motor, and send the analog signal to the motor controller 1402, where the motor controller 1402 may convert the analog signal into a corresponding digital signal and decode the digital signal to obtain a rotation speed signal of the motor.

The motor controller 1402 implements the suppression of the motor rotation speed jitter according to the method from step 302 to step 305 in the first embodiment of the method.

In addition, the motor controller 1402 is further configured to obtain a direct-axis current deviation signal and a quadrature-axis current deviation signal of the motor; fourier analysis is respectively carried out on the motor direct-axis current deviation signal and the motor quadrature-axis current deviation signal to obtain the frequency and the amplitude of effective components causing current jitter in direct-axis current and quadrature-axis alternating current; obtaining parameters for suppressing the current jitter according to the frequency and the amplitude of the effective component causing the current jitter; obtaining direct axis compensation voltage and quadrature axis compensation voltage through a resonance control link by utilizing the parameter for inhibiting the current jitter; and superposing the direct axis compensation voltage and the quadrature axis compensation voltage with the output direct axis voltage and the output quadrature axis voltage respectively to inhibit current jitter.

Specifically, the motor controller 1402 may further implement suppression of current jitter according to the method described in method embodiment two.

Fig. 15 is a system topology diagram for suppressing the electric vehicle shake in practical implementation.

The rotational speed jitter suppression module 1501 is the rotational speed jitter suppression module shown in fig. 5, and the current jitter suppression module 1502 is the current jitter suppression module shown in fig. 7.

According to the system for inhibiting the electric automobile from shaking, when the working condition of the electric automobile changes, the frequencies of the effective components which cause the rotating speed shaking and are obtained through Fourier analysis are different, and further the parameters for inhibiting the rotating speed shaking are obtained according to the frequencies and the amplitudes of the effective components and are different, so that the parameters for inhibiting the rotating speed shaking can be obtained in real time according to the working condition of the electric automobile, the working condition of the electric automobile for manually adjusting the parameters for inhibiting the shaking according to the current working condition of the electric automobile is not needed to be self-adaptive, and the adaptability of the system is enhanced. In addition, in the system provided by this embodiment, compensation torque needs to be obtained according to the parameter for suppressing rotational speed jitter and the rotational speed signal through the combined action of the differential inertia link and the band-pass filtering link, so that the problem that the rotational speed fluctuation amount extracted has a direct offset when the vehicle is in an accelerated operation working condition is solved. In summary, the method for inhibiting the electric vehicle from shaking provided by the application can effectively inhibit the shaking of the electric vehicle, improves the driving comfort, and reduces the mechanical resonance generated during shaking due to the inhibition of the shaking of the electric vehicle, thereby reducing the abrasion to hardware on the electric vehicle.

In addition, the system for suppressing the electric vehicle from shaking provided by the embodiment further suppresses the current shaking generated when the electric vehicle works in a high frequency band on the basis of suppressing the rotation speed shaking, so that the driving comfort can be ensured when the electric vehicle works in any frequency, and the hardware structure in the vehicle can be protected all the time.

In addition, in the embodiment of the present invention, the motor controller directly performs the rotation speed jitter suppression and the current jitter suppression, rather than the vehicle controller, so that the signal delay problem of the jitter suppression performed by the vehicle controller shown in fig. 2 does not exist in the embodiment.

The above embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions in the embodiments of the present application.

Claims (17)

1. A method for suppressing electric vehicle judder, comprising:

acquiring a rotating speed signal of a motor;

carrying out Fourier analysis on the rotating speed signal to obtain the frequency and amplitude of an effective component causing rotating speed jitter in the rotating speed signal; the rotating speed jitter is jitter caused by a nonlinear relation between the traction torque and the resisting torque of the electric automobile;

obtaining a parameter for inhibiting the rotation speed jitter according to the frequency and the amplitude of the effective component causing the rotation speed jitter;

obtaining a compensation torque through a differential inertia link and a band-pass filtering link according to the parameter for inhibiting the rotating speed jitter and the rotating speed signal;

and superposing the compensation torque and the given torque to suppress the rotation speed jitter.

2. The method for suppressing the jitter of the electric vehicle according to claim 1, wherein the fourier analysis is performed on the rotation speed signal to obtain the frequency and the amplitude of the effective component of the rotation speed signal, which causes the jitter of the rotation speed, and specifically comprises:

carrying out Fourier analysis on the rotating speed signal to obtain the amplitude of each component in the rotating speed signal;

taking the component with the maximum amplitude as an effective component causing the rotation speed jitter;

and obtaining the frequency and the amplitude of the effective component causing the rotation speed jitter.

3. The method for suppressing electric vehicle judder according to claim 1, wherein the compensating torque is superimposed with a given torque, and wherein the method further comprises:

carrying out amplitude limiting on the compensation torque to obtain the compensation torque after amplitude limiting;

the step of superposing the compensation torque and the given torque comprises the following specific steps:

and superposing the limited compensation torque and the given torque.

4. The method for suppressing the jitter of the electric vehicle according to claim 2, wherein a compensation torque is obtained through a differential inertia link and a band-pass filtering link according to the parameter for suppressing the rotational speed jitter and the rotational speed signal, and specifically comprises:

obtaining a compensation torque by the following transfer function;

<mrow> <msub> <mi>G</mi> <mi>n</mi> </msub> <mrow> <mo>(</mo> <mi>s</mi> <mo>)</mo> </mrow> <mo>=</mo> <mfrac> <mrow> <msub> <mi>T</mi> <mn>1</mn> </msub> <msubsup> <mi>&amp;omega;</mi> <mi>n</mi> <mn>2</mn> </msubsup> <msup> <mi>s</mi> <mn>2</mn> </msup> </mrow> <mrow> <msub> <mi>T</mi> <mn>3</mn> </msub> <msup> <mi>s</mi> <mn>3</mn> </msup> <mo>+</mo> <mrow> <mo>(</mo> <mn>2</mn> <msub> <mi>&amp;xi;&amp;omega;</mi> <mi>n</mi> </msub> <msub> <mi>T</mi> <mn>2</mn> </msub> <mo>+</mo> <mn>1</mn> <mo>)</mo> </mrow> <msup> <mi>s</mi> <mn>2</mn> </msup> <mo>+</mo> <mrow> <mo>(</mo> <msub> <mi>T</mi> <mn>2</mn> </msub> <msubsup> <mi>&amp;omega;</mi> <mi>n</mi> <mn>2</mn> </msubsup> <mo>+</mo> <mn>2</mn> <msub> <mi>&amp;xi;&amp;omega;</mi> <mi>n</mi> </msub> <mo>)</mo> </mrow> <mi>s</mi> <mo>+</mo> <msubsup> <mi>&amp;omega;</mi> <mi>n</mi> <mn>2</mn> </msubsup> </mrow> </mfrac> </mrow>

wherein, ω is_nCenter frequency for bandpass filtering, damping coefficient, T, ξ₁Pass band gain, T, for band pass filtering₂The turning frequency of the differential inertia element; s is a laplace variable;

<mrow> <msub> <mi>T</mi> <mn>1</mn> </msub> <mo>=</mo> <msup> <msub> <mi>aA</mi> <mn>1</mn> </msub> <mo>*</mo> </msup> <mo>,</mo> <msub> <mi>T</mi> <mn>2</mn> </msub> <mo>=</mo> <mfrac> <mn>1</mn> <mrow> <mn>10</mn> <msup> <msub> <mi>f</mi> <mn>1</mn> </msub> <mo>*</mo> </msup> </mrow> </mfrac> <mo>,</mo> <msub> <mi>&amp;omega;</mi> <mi>n</mi> </msub> <mo>=</mo> <mn>2</mn> <msup> <msub> <mi>&amp;pi;f</mi> <mn>1</mn> </msub> <mo>*</mo> </msup> <mo>,</mo> <mi>&amp;xi;</mi> <mo>=</mo> <mi>b</mi> <mo>;</mo> </mrow>

wherein f is₁ ^*The frequency of the effective component causing the rotation speed jitter is obtained; a. the₁ ^*The amplitude of the effective component causing the rotation speed jitter is obtained; a and b are coefficients for adjusting the on-gain and the pass-band width, respectively.

5. The method for suppressing the jitter of the electric vehicle according to claim 1, wherein the obtaining of the parameters for suppressing the rotational speed jitter according to the frequency and the amplitude of the effective component causing the rotational speed jitter specifically comprises:

frequency f of the effective component which will cause rotational speed jitter₁ ^*And amplitude A₁ ^*Obtaining a parameter for inhibiting the rotation speed jitter through the following formula; the parameters for inhibiting the rotation speed jitter are respectively as follows: pass band gain T of band pass filter₁Turning frequency T of differential inertia element₂Center frequency omega of band-pass filter_nAnd damping coefficient ξ;

T₁＝aA₁ ^*

<mrow> <msub> <mi>T</mi> <mn>2</mn> </msub> <mo>=</mo> <mfrac> <mn>1</mn> <mrow> <mn>10</mn> <msup> <msub> <mi>f</mi> <mn>1</mn> </msub> <mo>*</mo> </msup> </mrow> </mfrac> </mrow>

ω_n＝2πf₁ ^*

ξ＝b

where a and b are coefficients for adjusting the on-gain and the pass-band width, respectively.

6. The method for suppressing electric vehicle judder according to claim 1, further comprising:

obtaining a direct-axis current deviation signal and a quadrature-axis current deviation signal of the motor;

fourier analysis is respectively carried out on the motor direct-axis current deviation signal and the motor quadrature-axis current deviation signal to obtain the frequency and the amplitude of effective components causing current jitter in direct-axis current and quadrature-axis alternating current;

obtaining parameters for suppressing the current jitter according to the frequency and the amplitude of the effective component causing the current jitter;

obtaining a direct axis compensation voltage and a quadrature axis compensation voltage through a resonance control link by utilizing the parameter for inhibiting current jitter, the direct axis current deviation signal and the quadrature axis current deviation signal;

and superposing the direct axis compensation voltage and the quadrature axis compensation voltage with the output direct axis voltage and the output quadrature axis voltage respectively to inhibit current jitter.

7. The method for suppressing electric vehicle vibration according to claim 6, wherein fourier analysis is performed on the motor direct-axis current deviation signal and quadrature-axis current deviation signal to obtain the frequency and amplitude of effective components causing current vibration in direct-axis current and quadrature-axis alternating current, and the method specifically comprises:

respectively carrying out Fourier analysis on the direct-axis current deviation signal and the quadrature-axis current deviation signal to respectively obtain the amplitude of each component in the direct-axis current deviation signal and the quadrature-axis current deviation signal;

taking the component with the maximum amplitude as an effective component causing current jitter;

and obtaining the frequency and the amplitude of effective components causing current jitter in the direct-axis current and the quadrature-axis alternating current.

8. The method for suppressing electric vehicle shake according to claim 6, wherein the direct axis compensation voltage and the quadrature axis compensation voltage are respectively superimposed with the output direct axis voltage and the output quadrature axis voltage, and before the method further comprises:

carrying out amplitude limiting on the direct axis compensation voltage and the quadrature axis compensation voltage to obtain an amplitude-limited direct axis compensation voltage and an amplitude-limited quadrature axis compensation voltage;

and superposing the direct axis compensation voltage and the quadrature axis compensation voltage with the output direct axis voltage and the output quadrature axis voltage respectively, specifically:

and superposing the direct axis compensation voltage after amplitude limiting and the quadrature axis compensation voltage after amplitude limiting with the output direct axis voltage and the output quadrature axis voltage respectively.

9. The method for suppressing electric vehicle shaking according to claim 7, wherein the obtaining of the direct axis compensation voltage and the quadrature axis compensation voltage through a resonance control unit by using the parameter for suppressing current shaking, the direct axis current deviation signal and the quadrature axis current deviation signal specifically comprises:

obtaining a direct axis compensation voltage and a quadrature axis compensation voltage through the following transfer functions;

<mrow> <msub> <mi>G</mi> <mi>i</mi> </msub> <mrow> <mo>(</mo> <mi>s</mi> <mo>)</mo> </mrow> <mo>=</mo> <mfrac> <mrow> <msub> <mi>k&amp;omega;</mi> <mi>c</mi> </msub> <mi>s</mi> </mrow> <mrow> <msup> <mi>s</mi> <mn>2</mn> </msup> <mo>+</mo> <msub> <mi>&amp;omega;</mi> <mi>c</mi> </msub> <mi>s</mi> <mo>+</mo> <msubsup> <mi>&amp;omega;</mi> <mn>0</mn> <mn>2</mn> </msubsup> </mrow> </mfrac> </mrow>

wherein, ω is_cA predetermined bandwidth, omega, for said resonant control link₀Is the center frequency, k is the gain, c is the preset coefficient for adjusting the gain; omega₀＝2πf₂ ^*，k＝c·A₂ ^*；f₂ ^*The frequency of the effective component causing the current jitter; a. the₂ ^*Is the amplitude of the effective component causing current jitter; s is the Laplace variable.

10. An apparatus for suppressing electric vehicle judder, comprising:

the acquisition unit is used for acquiring a rotating speed signal of the motor;

the rotating speed jitter effective component obtaining unit is used for carrying out Fourier analysis on the rotating speed signal to obtain the frequency and the amplitude of an effective component causing rotating speed jitter in the rotating speed signal; the rotating speed jitter is jitter caused by a nonlinear relation between the traction torque and the resisting torque of the electric automobile;

the rotation speed jitter suppression parameter obtaining unit is used for obtaining a rotation speed jitter suppression parameter according to the frequency and the amplitude of the effective component causing rotation speed jitter;

the compensation torque obtaining unit is used for obtaining compensation torque through a differential inertia link and a band-pass filtering link according to the parameter for inhibiting the rotating speed jitter and the rotating speed signal;

and the rotational speed jitter suppression unit is used for superposing the compensation torque and given torque so as to suppress the rotational speed jitter.

11. The apparatus for suppressing shaking of an electric vehicle according to claim 10, wherein the rotational speed shaking effective component obtaining unit includes:

the rotating speed signal component obtaining subunit is used for carrying out Fourier analysis on the rotating speed signal to obtain the amplitude of each component in the rotating speed signal;

a rotational speed jitter effective component obtaining subunit, configured to take the component with the largest amplitude as an effective component causing rotational speed jitter;

and the frequency and amplitude first obtaining subunit is used for obtaining the frequency and amplitude of the effective component causing the rotating speed jitter.

12. The apparatus for suppressing electric vehicle judder according to claim 10, further comprising: a torque limiter unit;

the torque amplitude limiting unit is used for carrying out amplitude limiting on the compensation torque to obtain the compensation torque after amplitude limiting;

and the rotating speed jitter suppression unit is used for superposing the limited compensation torque and the given torque.

13. The apparatus for suppressing electric vehicle judder according to claim 10, further comprising:

the current deviation signal obtaining unit is used for obtaining a direct-axis current deviation signal and a quadrature-axis current deviation signal of the motor;

the current jitter effective component obtaining unit is used for respectively carrying out Fourier analysis on the direct-axis current deviation signal and the quadrature-axis current deviation signal of the motor to obtain the frequency and the amplitude of an effective component causing current jitter in direct-axis current and quadrature-axis alternating current;

a current jitter suppression parameter obtaining unit for obtaining a current jitter suppression parameter from the frequency and amplitude of the effective component causing current jitter;

the compensation voltage obtaining unit is used for obtaining direct axis compensation voltage and quadrature axis compensation voltage through a resonance control link by utilizing the parameter for inhibiting current jitter, the direct axis current deviation signal and the quadrature axis current deviation signal;

and the current jitter suppression unit is used for respectively superposing the direct axis compensation voltage and the quadrature axis compensation voltage with the output direct axis voltage and the output quadrature axis voltage so as to suppress current jitter.

14. The apparatus for suppressing electric vehicle judder according to claim 13, wherein the current judder effective component obtaining unit includes:

the current deviation signal component obtaining subunit is used for respectively carrying out Fourier analysis on the direct-axis current deviation signal and the quadrature-axis current deviation signal and respectively obtaining the amplitude of each component in the direct-axis current deviation signal and the quadrature-axis current deviation signal;

a current jitter effective component obtaining subunit, configured to take a component with the largest amplitude as an effective component causing current jitter;

and the frequency and amplitude second obtaining subunit is used for obtaining the frequency and amplitude of effective components causing current jitter in the direct-axis current and the quadrature-axis alternating current.

15. The apparatus for suppressing electric vehicle judder according to claim 13, further comprising: a voltage amplitude limiting unit;

the voltage amplitude limiting unit is used for carrying out amplitude limiting on the direct axis compensation voltage and the quadrature axis compensation voltage to obtain an amplitude-limited direct axis compensation voltage and an amplitude-limited quadrature axis compensation voltage;

and the current jitter suppression unit is used for superposing the amplitude-limited direct axis compensation voltage and the amplitude-limited quadrature axis compensation voltage with the output direct axis voltage and the output quadrature axis voltage respectively.

16. A system for inhibiting shaking of an electric vehicle is applied to control of a motor of the electric vehicle, and comprises: a speed sensor and a motor controller;

the rotating speed sensor is used for acquiring a rotating speed signal of the motor;

the motor controller is used for carrying out Fourier analysis on the rotating speed signal to obtain the frequency and amplitude of an effective component causing rotating speed jitter in the rotating speed signal; the rotating speed jitter is jitter caused by a nonlinear relation between the traction torque and the resisting torque of the electric automobile; obtaining a parameter for inhibiting the rotation speed jitter according to the frequency and the amplitude of the effective component causing the rotation speed jitter; obtaining a compensation torque through a differential inertia link and a band-pass filtering link according to the parameter for inhibiting the rotating speed jitter and the rotating speed signal; and superposing the compensation torque and the given torque to suppress the rotation speed jitter.

17. The system for suppressing jitter in an electric vehicle of claim 16, wherein the motor controller is further configured to obtain a motor direct current offset signal and a motor quadrature current offset signal; fourier analysis is respectively carried out on the motor direct-axis current deviation signal and the motor quadrature-axis current deviation signal to obtain the frequency and the amplitude of effective components causing current jitter in direct-axis current and quadrature-axis alternating current; obtaining parameters for suppressing the current jitter according to the frequency and the amplitude of the effective component causing the current jitter; obtaining a direct axis compensation voltage and a quadrature axis compensation voltage through a resonance control link by utilizing the parameter for inhibiting current jitter, the direct axis current deviation signal and the quadrature axis current deviation signal; and superposing the direct axis compensation voltage and the quadrature axis compensation voltage with the output direct axis voltage and the output quadrature axis voltage respectively to inhibit current jitter.