CN113459823B - Method and device for suppressing jitter of electric automobile, electric automobile and storage medium - Google Patents

Method and device for suppressing jitter of electric automobile, electric automobile and storage medium Download PDF

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Publication number
CN113459823B
CN113459823B CN202010242482.7A CN202010242482A CN113459823B CN 113459823 B CN113459823 B CN 113459823B CN 202010242482 A CN202010242482 A CN 202010242482A CN 113459823 B CN113459823 B CN 113459823B
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pass filter
order
torque
order band
rotating speed
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CN113459823A (en
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胡荣光
戚邦圳
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Anhui Welling Auto Parts Co Ltd
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Anhui Welling Auto Parts Co Ltd
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L15/00—Methods, circuits, or devices for controlling the traction-motor speed of electrically-propelled vehicles
    • B60L15/20—Methods, circuits, or devices for controlling the traction-motor speed of electrically-propelled vehicles for control of the vehicle or its driving motor to achieve a desired performance, e.g. speed, torque, programmed variation of speed
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L2240/00—Control parameters of input or output; Target parameters
    • B60L2240/40—Drive Train control parameters
    • B60L2240/42—Drive Train control parameters related to electric machines
    • B60L2240/421—Speed
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L2240/00—Control parameters of input or output; Target parameters
    • B60L2240/40—Drive Train control parameters
    • B60L2240/42—Drive Train control parameters related to electric machines
    • B60L2240/423—Torque
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/60—Other road transportation technologies with climate change mitigation effect
    • Y02T10/72—Electric energy management in electromobility

Abstract

The invention discloses an electric automobile jitter suppression method and device, an electric automobile and a storage medium, wherein the electric automobile jitter suppression method comprises the following steps: acquiring the motor rotating speed of the electric automobile; continuously performing second-order filtering treatment on the rotating speed of the motor twice to obtain the rotating speed jitter; generating a torque compensation value according to the rotation speed jitter amount; and superposing the torque compensation value with the given torque to restrain the vibration of the electric automobile. According to the electric vehicle vibration suppression method, the rotating speed vibration quantity is obtained by continuously performing second-order filtering processing on the rotating speed of the motor twice, the torque compensation value is generated according to the rotating speed vibration quantity, and the torque compensation value is overlapped with the given torque to control the motor, so that the vibration of the electric vehicle can be effectively suppressed, the riding comfort is improved, and the working performance and the service life of a transmission system are improved.

Description

Method and device for suppressing jitter of electric automobile, electric automobile and storage medium
Technical Field
The invention relates to the technical field of automobiles, in particular to an electric automobile jitter suppression method and device, an electric automobile and a storage medium.
Background
The pure electric automobile mostly adopts a power assembly mode of integrated driving of a motor and a transmission, and wheels are driven by a reduction/differential mechanism and left and right half shafts through a secondary gear. The direct coupling and constant meshing structure is favorable for obtaining better acceleration performance, but brings the problem of shafting vibration. The vibration is particularly obvious when the motor torque changes rapidly, particularly, large positive/negative torque is suddenly added during rapid acceleration/deceleration, and torque interference is caused by external factors in the shafting transmission process. Because the output torque of the motor can be directly controlled by the controller according to the torque command, the rotating speed of the motor is jointly determined by the torque of the motor and the shafting transmission system. Therefore, shafting vibration is particularly reflected in the shaking of the motor rotating speed, and the shaking of the rotating speed can seriously affect the riding comfort of the electric automobile.
Disclosure of Invention
The present invention aims to solve at least one of the technical problems in the related art to some extent. Therefore, a first object of the present invention is to provide a method for suppressing the shake of an electric vehicle, so as to improve riding comfort, and improve the working performance and the service life of a transmission system.
A second object of the present invention is to propose a computer readable storage medium.
A third object of the present invention is to provide an electric vehicle shake suppression device.
A fourth object of the present invention is to provide an electric vehicle.
In order to achieve the above object, an embodiment of a first aspect of the present invention provides a method for suppressing vibration of an electric vehicle, the method including the steps of: acquiring the motor rotating speed of the electric automobile; continuously performing second-order filtering processing on the motor rotating speed for two times to obtain rotating speed jitter, wherein the first second-order filtering processing is performed by adopting a first second-order band-pass filter, the second-order filtering processing is performed by adopting a second-order band-pass filter, and the center frequency of the first second-order band-pass filter and the center frequency of the second-order band-pass filter are rotating speed jitter frequencies determined according to the motor rotating speed; generating a torque compensation value according to the rotational speed jitter amount; and superposing the torque compensation value with a given torque to restrain the electric automobile from shaking.
According to the method for suppressing the vibration of the electric automobile, the rotating speed vibration quantity is obtained by continuously performing second-order filtering processing on the rotating speed of the motor twice, the torque compensation value is generated according to the vibration quantity, and the torque compensation value is overlapped with the given torque to control the motor, so that the vibration of the electric automobile can be effectively suppressed, riding comfort is improved, and the working performance and the service life of a transmission system are improved.
In addition, the method for suppressing the shake of the electric automobile in the embodiment of the invention can also have the following additional technical characteristics:
according to one embodiment of the invention, the motor speed is subjected to two successive second order filtering processes by the following formula:
Figure BDA0002433019710000021
wherein G is s B is a transfer function 1 For the bandwidth of the first second order band pass filter, B 2 For the bandwidth of the second order band-pass filter, s is Laplacian, omega 0 Is the center frequency of the first second order band pass filter and the center frequency of the second order band pass filter.
According to one embodiment of the invention, the bandwidth of the first second order bandpass filter is determined from the center frequency of the first second order bandpass filter, and the bandwidth of the second order bandpass filter is determined from the center frequency of the second order bandpass filter.
According to one embodiment of the present invention, the torque compensation value is obtained by multiplying the rotational speed shake amount by a gain coefficient, wherein the gain coefficient obtaining step includes: setting the center frequency at which the bandwidths of the first second-order band-pass filter and the second-order band-pass filter are twice; the initial value of the gain factor is calculated by the following formula: k (K) 0 =0.5×Δte/Am, where K 0 For the initial value of the gain factor, Δte=te 1 -Te 0 Te is the torque variation amount at the time of given torque abrupt change 1 Te for the abrupt given torque 0 For the given torque before abrupt change, am is the amplitude of the cross variable obtained after the first second-order band-pass filter and the second-order band-pass filter are cascaded for the obtained motor rotating speed when the torque compensation value is not overlapped with the given torque; and adjusting the initial value of the gain coefficient to enable the jitter amplitude of the motor rotating speed to be in a first preset range.
According to an embodiment of the present invention, the second-order band-pass filter has a bandwidth twice the center frequency, and the first second-order band-pass filter has a bandwidth obtained by: setting the central frequency of which the bandwidth initial value of the first second-order band-pass filter is twice; after the torque compensation value is overlapped with the given torque, acquiring the adjustment time of the output of the first second-order band-pass filter and the output of the second-order band-pass filter after cascading, and acquiring the direct current bias of the torque obtained after the torque compensation value is overlapped with the given torque; and adjusting the initial value of the bandwidth of the first second-order band-pass filter so as to enable the adjusting time to be in a second preset range and enable the direct current bias to be in a third preset range.
In order to achieve the above object, an embodiment of a second aspect of the present invention proposes a computer-readable storage medium, which when executed by a processor, implements the electric vehicle shake suppression method as described in the above embodiment.
The computer readable storage medium of the embodiment of the invention can effectively inhibit the shake of the electric automobile when the computer program stored on the computer readable storage medium and corresponding to the shake inhibition method of the electric automobile is executed by a processor, thereby improving riding comfort, and improving the working performance and the service life of a transmission system.
In order to achieve the above object, an embodiment of a third aspect of the present invention provides an electric vehicle shake suppression device, including: the filtering module is used for continuously performing second-order filtering processing on the motor rotating speed for two times to obtain rotating speed jitter, wherein the filtering module comprises a first second-order band-pass filter and a second-order band-pass filter which are cascaded, and the center frequency of the first second-order band-pass filter and the center frequency of the second-order band-pass filter are rotating speed jitter frequencies determined according to the motor rotating speed; the generation module is used for generating a torque compensation value according to the rotation speed jitter quantity; and the control module is used for superposing the torque compensation value with a given torque so as to inhibit the shake of the electric automobile.
According to the electric vehicle vibration suppression device provided by the embodiment of the invention, the rotating speed vibration quantity is obtained by continuously performing two-step filtering processing on the rotating speed of the motor, the torque compensation value is generated according to the vibration quantity, and the torque compensation value is overlapped with the given torque to control the motor, so that the vibration of the electric vehicle can be effectively suppressed, the riding comfort is improved, and the working performance and the service life of a transmission system are improved.
In addition, the electric vehicle shake suppression device according to the above embodiment of the present invention may further have the following additional technical features:
according to one embodiment of the invention, the filtering module performs two second order filtering processes on the motor rotation speed in succession by the following formula:
Figure BDA0002433019710000031
wherein G is s B is a transfer function 1 Bandwidth of first second-order bandpass filter used for first second-order filtering process, B 2 Second order for second order filteringBand-pass filter bandwidth, s is Laplacian, ω 0 Is the center frequency of the first second order band pass filter and the center frequency of the second order band pass filter.
According to one embodiment of the invention, the bandwidth of the first second order bandpass filter is determined from the center frequency of the first second order bandpass filter, and the bandwidth of the second order bandpass filter is determined from the center frequency of the second order bandpass filter.
In order to achieve the above object, a fourth aspect of the present invention provides an electric vehicle including the electric vehicle shake suppression device according to the above embodiment.
According to the electric vehicle disclosed by the embodiment of the invention, the electric vehicle shake can be effectively restrained by the electric vehicle shake restraining device, so that riding comfort is improved, and the working performance and the service life of a transmission system are improved.
Drawings
The foregoing and/or additional aspects and advantages of the invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings, in which:
fig. 1 is a flowchart of an electric vehicle shake suppression method according to an embodiment of the present invention;
FIG. 2 is a block diagram of a motor control system according to one embodiment of the present invention;
FIG. 3 is a flow chart of a method for gain factor acquisition in one embodiment of the present invention;
FIG. 4 is a flow chart of a method for acquiring bandwidth of a first second order bandpass filter according to one embodiment of the invention;
FIG. 5 is a graph of output torque versus rotational speed response for torque jump without torque compensation;
FIG. 6 is a graph of output torque versus rotational speed response for torque jump during torque compensation using the method of the present invention;
FIG. 7 is a graph of output torque and rotational speed response for torque jump at torque jump when torque compensation is based on a second order filter;
FIG. 8 is a graph of the torque on the shaft versus rotational speed for load disturbance without torque compensation;
FIG. 9 is a graph of torque versus rotational speed on a shaft corresponding to load disturbances when torque compensation is performed using the method of the present invention;
fig. 10 is a block diagram of a structure of an electric vehicle shake suppression apparatus according to an embodiment of the present invention;
fig. 11 is a block diagram of an electric vehicle according to an embodiment of the present invention.
Detailed Description
Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the drawings are illustrative and intended to explain the present invention and should not be construed as limiting the invention.
The following describes an electric vehicle shake suppression method, an apparatus, a computer-readable storage medium, and an electric vehicle according to embodiments of the present invention with reference to the accompanying drawings.
Fig. 1 is a flowchart of an electric vehicle shake suppression method according to an embodiment of the present invention.
As shown in fig. 1, the electric vehicle shake suppression method includes the steps of:
s1, acquiring the motor rotating speed of the electric automobile.
As shown in fig. 2, motor rotation speed ω m Can be acquired by a rotary encoder.
S2, continuously performing second-order filtering processing on the rotating speed of the motor twice to obtain the rotating speed jitter.
The first second-order filtering process is performed by a first second-order band-pass filter, the second-order filtering process is performed by a second-order band-pass filter, and the center frequency of the first second-order band-pass filter and the center frequency of the second-order band-pass filter are rotation speed jitter frequencies determined according to the rotation speed of the motor.
And S3, generating a torque compensation value according to the rotation speed jitter amount.
As an example, referring to fig. 2, steps S2-S3 may be implemented by a torque compensator, wherein the torque compensator comprises a cascaded gain unit, a first second order bandpass filter and a second order bandpass filter.
And S4, superposing the torque compensation value and the given torque to restrain the shake of the electric automobile.
In this embodiment, referring to fig. 2, an initial torque command, i.e., a given torque, issued by the VCU (Vehicle control unit, vehicle controller) or rotational speed control unit is received
Figure BDA0002433019710000041
After that, a current command is issued via the torque control unit>
Figure BDA0002433019710000042
Then sends out a voltage command through the current control unit>
Figure BDA0002433019710000043
The inverter switching signals are output to a SVPWM (Space Vector Pulse Width Modulation ) module. The inverter outputs a PWM (Pulse Width Modulation ) voltage, generates a current in a motor winding, and outputs a torque. The motor rotor shaft is connected with a traditional system formed by a gear and a reduction/differential mechanism, and transmits torque to a wheel shaft to drive wheels of the electric automobile to rotate. The mutual coupling of the motor and the mechanical transmission system is such that there is a resonance frequency during the rotational speed of the motor torque generation, i.e. the gain at this frequency is the maximum point and the phase offset is zero. When torque is suddenly added/subtracted, motor rotation speed is easy to shake, and riding comfort is affected.
In order that the resulting torque command means after superposition does not deviate from the original torque command, affecting the accuracy of torque control and torque output capacity, the ideal compensating torque should not contain a dc offset, so the filter should have a sufficient decay rate at low frequencies. Since the phase shift from torque to rotational speed is zero at this resonance frequency, the feedback compensation should have no phase shift at this frequency in order to ensure jitter suppression performance and avoid control disturbances after compensation. When the torque is stabilized, the rotational speed also tends to be stabilized after the shake, and therefore, the magnitude of the shake amount thereof is varied. Based on this, the filter is set as two cascaded second order bandpass filters, namely a first second order bandpass filter and a second order bandpass filter. Optionally, the filter has an attenuation rate of-40 dB/10 times the frequency in the low frequency band. In the embodiment of the invention, the center frequency of the first second-order band-pass filter and the center frequency of the second-order band-pass filter are both rotational speed jitter frequencies determined according to the rotational speed of the motor, so that the required jitter amount can be filtered out while the phase is kept unchanged. Because the frequency electric automobile is related to a mechanical structure, the frequency electric automobile can be obtained through the frequency spectrum analysis of the motor rotation speed during the off-line calibration or the on-line operation of the primary resonance of the real automobile.
Referring to fig. 2, a torque compensation value Δt may be calculated based on the rotational speed by the torque compensator e Specifically, the sampled motor rotation speed is subjected to filtering processing through a first second-order band-pass filter and a second-order band-pass filter which are cascaded, and then the motor rotation speed after the filtering processing is subjected to gain unit processing (namely multiplication with a gain coefficient A, wherein the A is a negative value), so that a torque compensation value is obtained, and the phase of the torque compensation value is not changed. Further, in the shake suppression control, the torque compensation value Δt e With a given torque
Figure BDA0002433019710000051
After superposition, the final control torque is obtained>
Figure BDA0002433019710000052
Therefore, the rotating speed shake can be effectively restrained, and the shake of the electric automobile is restrained, so that riding comfort is improved, and the working performance and the service life of a transmission system are improved.
In one example of the present invention, the motor rotation speed is subjected to two successive second order filtering processes by the following formula:
Figure BDA0002433019710000053
wherein the method comprises the steps of，G s B is a transfer function 1 For the bandwidth of the first-order band-pass filter, B 2 Is the bandwidth of the second-order band-pass filter, s is the Laplacian, omega 0 Is the center frequency of the first second order band pass filter and the center frequency of the second order band pass filter.
According to the sampling frequency f s Discretizing the band-pass filter, as shown in the following formula:
Figure BDA0002433019710000054
wherein z is a discrete transform operator, B 1 For the bandwidth of the first-order band-pass filter, B 2 For the bandwidth, ω, of the second order band pass filter 0 Is the center frequency of the first second order band pass filter and the center frequency of the second order band pass filter.
In one embodiment of the present invention, the center frequency of the first second-order band-pass filter and the center frequency of the second-order band-pass filter are rotational speed shake frequencies determined according to the rotational speed of the motor, whereby it is possible to ensure that the required shake amount is filtered out while maintaining the phase unchanged. Because the frequency electric automobile is related to a mechanical structure, the frequency electric automobile can be obtained through the frequency spectrum analysis of the motor rotation speed during the off-line calibration or the on-line operation of the primary resonance of the real automobile.
In one embodiment of the present invention, the torque compensation value is obtained by multiplying the rotational speed jitter amount by the gain coefficient, and after setting the center frequency of the first second-order band-pass filter and the center frequency of the second-order band-pass filter to the rotational speed jitter frequency, the gain of the band-pass filter is 1, so that the gain coefficient only needs to be adjusted in the whole filtering link. As shown in fig. 3, the gain coefficient obtaining step includes:
s10, setting the central frequency of which the bandwidths of the first second-order band-pass filter and the second-order band-pass filter are twice.
S20, calculating an initial value of the gain coefficient by the following formula: k (K) 0 =0.5×Δte/Am, where K 0 For initial value of gain factor, ΔTe＝Te 1 -Te 0 Te is the torque variation amount at the time of given torque abrupt change 1 Te for the abrupt given torque 0 For the given torque before abrupt change, am is the amplitude of the cross variable obtained after the obtained motor rotating speed is filtered by the cascaded first second-order band-pass filter and the cascaded second-order band-pass filter when the torque compensation value is not overlapped with the given torque.
S30, adjusting the initial value of the gain coefficient to enable the jitter amplitude of the motor rotation speed to be in a first preset range.
Specifically, when the initial value of the gain coefficient is adjusted, the torque compensation value is superimposed with the given torque to perform the shake control on the electric vehicle. In the control process, the gain coefficient is adjusted according to the shaking amplitude of the motor rotating speed until the shaking amplitude of the motor rotating speed is in a first preset range. The first preset range can be set according to parameters such as road conditions, vehicle conditions, user precision requirements and the like, and the first preset range is not limited.
In one embodiment of the present invention, the step of obtaining the bandwidth of the first second order band-pass filter by obtaining the bandwidth of the second order band-pass filter with a center frequency twice as high as the bandwidth of the first second order band-pass filter, as shown in fig. 4, includes:
s100, setting the bandwidth initial value of the first second-order band-pass filter to be twice the center frequency.
And S200, after the torque compensation value is overlapped with the given torque, acquiring the adjustment time of the output of the first second-order band-pass filter and the second-order band-pass filter after cascading, and acquiring the direct current bias of the torque obtained after the torque compensation value is overlapped with the given torque.
S300, adjusting the initial value of the bandwidth of the first second-order band-pass filter so as to enable the adjusting time to be in a second preset range and enable the direct current bias to be in a third preset range.
The second preset range and the third preset range are set according to parameters such as road condition, vehicle condition, user precision requirement and the like, and the second preset range and the third preset range are not limited.
The following describes the beneficial effects of the electric vehicle shake suppression method according to the embodiment of the present invention with reference to fig. 5 to 9:
fig. 5 is a graph of output torque versus rotational speed response for torque abrupt change without torque compensation. Referring to fig. 5, the given torque is suddenly increased from 80Nm to 200Nm and then suddenly decreased to 100Nm, the motor rotation speed generates obvious vibration, and at the moment of torque abrupt change, the rotation speed vibration is maximum, and then the vibration amplitude gradually decays. Fig. 6 is a graph of output torque versus rotational speed response for torque jump when torque compensation is performed using the method of the present invention. Referring to fig. 6, after the torque compensator of the present invention is added, the rotational speed at the time of torque abrupt change can be maintained to be relatively smooth, and the jitter thereof is significantly suppressed. The rotational speed adjustment is stable after 0.3s, the output torque is not changed any more, and the torque command can be kept consistent. Fig. 7 is a graph of output torque and rotational speed response for torque sudden change after torque compensation based on a second order filter. Referring to fig. 7, a second order band-pass filter is used for torque compensation, and rotational speed jitter can be well suppressed. However, since a second order filter has limited suppression of dc offset, the compensation torque contains a large amount of dc, and the compensated output torque has a significant deviation from the initial torque command, which affects the torque output capability. Therefore, the electric vehicle shake suppression method can effectively suppress electric vehicle shake, so that riding comfort is improved, and working performance and service life of a transmission system are improved.
Rotational speed jerk may also be caused due to torque and load disturbances on the driveline, as shown in fig. 8. If no active torque compensation measures are taken, the natural decay of the rotational speed jitter will last longer, and the rotational speed jitter can be well suppressed after the torque compensation method of the present invention is adopted, and the result is shown in fig. 9. Therefore, the electric vehicle shake suppression method can effectively suppress electric vehicle shake, so that riding comfort is improved, and working performance and service life of a transmission system are improved.
In summary, the method for suppressing the shake of the electric automobile can effectively suppress the shake of the rotating speed of the electric automobile, thereby improving the riding comfort of the electric automobile and simultaneously improving the working performance and the service life of a transmission system.
Further, the present invention proposes a computer-readable storage medium having stored thereon a computer program which, when processed and executed, implements the electric vehicle shake suppression method in the above-described embodiments.
The computer readable storage medium of the embodiment of the invention can effectively inhibit the rotating speed shake of the electric automobile when the computer program stored on the computer readable storage medium and corresponding to the electric automobile shake inhibition method is executed by a processor, thereby improving the riding comfort of the electric automobile and simultaneously improving the working performance and the service life of a transmission system.
Fig. 10 is a block diagram of an electric vehicle shake suppression device according to an embodiment of the present invention.
In this embodiment, as shown in fig. 10, the suppression apparatus 100 includes an acquisition module 10, a filtering module 20, a generation module 30, and a control module 40.
The obtaining module 10 is configured to obtain a motor rotation speed of the electric vehicle, and the filtering module 20 is configured to continuously perform two-order filtering processing on the motor rotation speed to obtain a rotation speed jitter amount, where the filtering module 20 includes a first second-order band-pass filter and a second-order band-pass filter that are cascaded, and a center frequency of the first second-order band-pass filter and a center frequency of the second-order band-pass filter are rotation speed jitter frequencies determined according to the motor rotation speed; the generating module 30 is configured to generate a torque compensation value according to the rotational speed jitter amount, and the control module 40 is configured to superimpose the torque compensation value on the given torque to suppress the electric vehicle jitter.
Alternatively, as shown in fig. 2, the filtering module 20 and the generating module 30 may be implemented by a torque compensator, wherein the torque compensator comprises a cascaded gain unit, a first second order bandpass filter and a second order bandpass filter.
In this embodiment, an initial torque command, i.e., a given torque, issued by the VCU (Vehicle control unit, vehicle controller) or speed control unit is received
Figure BDA0002433019710000071
After that, a current command is issued via the torque control unit>
Figure BDA0002433019710000072
Then sends out a voltage command through the current control unit>
Figure BDA0002433019710000081
The inverter switching signals are output to a SVPWM (Space Vector Pulse Width Modulation ) module. The inverter outputs PWM (Pulse Width Modulation ) voltage, generates current in the motor winding, outputs torque, and realizes control of the motor, wherein the motor rotation speed omega m Can be acquired by a rotary encoder. The motor rotor shaft is connected with a traditional system formed by a gear and a reduction/differential mechanism, and transmits torque to a wheel shaft to drive wheels of the electric automobile to rotate. The mutual coupling of the motor and the mechanical transmission system is such that there is a resonance frequency during the rotational speed of the motor torque generation, i.e. the gain at this frequency is the maximum point and the phase offset is zero. When torque is suddenly added/subtracted, motor rotation speed is easy to shake, and riding comfort is affected.
In order that the resulting torque command means after superposition does not deviate from the original torque command, affecting the accuracy of torque control and torque output capacity, the ideal compensating torque should not contain a dc offset, so the filter should have a sufficient decay rate at low frequencies. Since the phase shift from torque to rotational speed is zero at this resonance frequency, the feedback compensation should have no phase shift at this frequency in order to ensure jitter suppression performance and avoid control disturbances after compensation. When the torque is stabilized, the rotational speed also tends to be stabilized after the shake, and therefore, the magnitude of the shake amount thereof is varied. Based on this, the filter may be set as two cascaded second order bandpass filters, namely a first second order bandpass filter and a second order bandpass filter. Optionally, the filter has an attenuation rate of-40 dB/10 times the frequency in the low frequency band. In the embodiment of the invention, the center frequency of the first second-order band-pass filter and the center frequency of the second-order band-pass filter are both rotational speed jitter frequencies determined according to the rotational speed of the motor, so that the required jitter amount can be filtered out while the phase is kept unchanged. Because the frequency electric automobile is related to a mechanical structure, the frequency electric automobile can be obtained through the frequency spectrum analysis of the motor rotation speed during the off-line calibration or the on-line operation of the primary resonance of the real automobile.
Referring to fig. 2, a torque compensation value Δt may be calculated based on the rotational speed by the torque compensator e Specifically, the sampled motor rotation speed is subjected to filtering processing through a first second-order band-pass filter and a second-order band-pass filter which are cascaded, and then the motor rotation speed after the filtering processing is subjected to gain unit processing (namely multiplication with a gain coefficient A, wherein the A is a negative value), so that a torque compensation value is obtained, and the phase of the torque compensation value is not changed. Further, in the shake suppression control, the torque compensation value Δt e With a given torque
Figure BDA0002433019710000082
After superposition, the final control torque is obtained>
Figure BDA0002433019710000083
Therefore, the rotating speed shake can be effectively restrained, and the shake of the electric automobile is restrained, so that riding comfort is improved, and the working performance and the service life of a transmission system are improved.
In one embodiment of the present invention, the filtering module 20 performs the second order filtering process on the motor speed two times in succession by the following formula:
Figure BDA0002433019710000084
wherein G is s B is a transfer function 1 Is the bandwidth of the first two-order band-pass filter, which can be determined according to the center frequency of the first two-order band-pass filter, B 2 Is the bandwidth of the second-order band-pass filter, which can be determined according to the center frequency of the second-order band-pass filter, s is the Laplacian, omega 0 Is the center frequency of the first second order band pass filter and the center frequency of the second order band pass filter.
According to the sampling frequency f s Discretizing the band-pass filter according to the following formulaThe following is shown:
Figure BDA0002433019710000091
wherein z is a discrete transform operator, B 1 For the bandwidth of the first-order band-pass filter, B 2 For the bandwidth, ω, of the second order band pass filter 0 Is the center frequency of the first second order band pass filter and the center frequency of the second order band pass filter.
In one embodiment of the present invention, after setting the center frequency of the first second-order band-pass filter and the center frequency of the second-order band-pass filter to the rotational speed dithering frequency, the gain of the band-pass filter is 1, so that the whole filtering link only needs to adjust the gain coefficient. As shown in fig. 3, the gain coefficient obtaining step includes:
s10, setting the central frequency of which the bandwidths of the first second-order band-pass filter and the second-order band-pass filter are twice.
S20, calculating an initial value of the gain coefficient by the following formula: k (K) 0 =0.5×Δte/Am, where K 0 For the initial value of the gain coefficient, Δte=te 1 -Te 0 Te is the torque variation amount at the time of given torque abrupt change 1 Te for the abrupt given torque 0 For the given torque before abrupt change, am is the amplitude of the cross variable obtained after the obtained motor rotating speed is filtered by the cascaded first second-order band-pass filter and the cascaded second-order band-pass filter when the torque compensation value is not overlapped with the given torque.
S30, adjusting the initial value of the gain coefficient to enable the jitter amplitude of the motor rotation speed to be in a first preset range.
Specifically, when the initial value of the gain coefficient is adjusted, the torque compensation value is superimposed with the given torque to perform the shake control on the electric vehicle. In the control process, the gain coefficient is adjusted according to the shaking amplitude of the motor rotating speed until the shaking amplitude of the motor rotating speed is in a first preset range. The first preset range can be set according to parameters such as road conditions, vehicle conditions, user precision requirements and the like, and the first preset range is not limited.
In one embodiment of the present invention, the step of obtaining the bandwidth of the first second order band-pass filter by obtaining the bandwidth of the second order band-pass filter with a center frequency twice as high as the bandwidth of the first second order band-pass filter, as shown in fig. 4, includes:
s100, setting the bandwidth initial value of the first second-order band-pass filter to be twice the center frequency.
And S200, after the torque compensation value is overlapped with the given torque, acquiring the adjustment time of the output of the first second-order band-pass filter and the second-order band-pass filter after cascading, and acquiring the direct current bias of the torque obtained after the torque compensation value is overlapped with the given torque.
S300, adjusting the initial value of the bandwidth of the first second-order band-pass filter so as to enable the adjusting time to be in a second preset range and enable the direct current bias to be in a third preset range.
The second preset range and the third preset range are set according to parameters such as road condition, vehicle condition, user precision requirement and the like, and the second preset range and the third preset range are not limited.
The following describes the beneficial effects of the electric vehicle shake suppression device according to the embodiment of the present invention with reference to fig. 5 to 9:
fig. 5 is a graph of output torque versus rotational speed response for torque abrupt change without torque compensation. Referring to fig. 5, the given torque is suddenly increased from 80Nm to 200Nm and then suddenly decreased to 100Nm, the motor rotation speed generates obvious vibration, and at the moment of torque abrupt change, the rotation speed vibration is maximum, and then the vibration amplitude gradually decays. Fig. 6 is a graph of output torque versus rotational speed response for torque jump when torque compensation is performed using the method of the present invention. Referring to fig. 6, after the torque compensator of the present invention is added, the rotational speed at the time of torque abrupt change can be maintained to be relatively smooth, and the jitter thereof is significantly suppressed. The rotational speed adjustment is stable after 0.3s, the output torque is not changed any more, and the torque command can be kept consistent. Fig. 7 is a graph of output torque and rotational speed response for torque sudden change after torque compensation based on a second order filter. Referring to fig. 7, a second order band-pass filter is used for torque compensation, and rotational speed jitter can be well suppressed. However, since a second order filter has limited suppression of dc offset, the compensation torque contains a large amount of dc, and the compensated output torque has a significant deviation from the initial torque command, which affects the torque output capability. Therefore, the electric vehicle shake suppression method can effectively suppress electric vehicle shake, so that riding comfort is improved, and working performance and service life of a transmission system are improved.
Rotational speed jerk may also be caused due to torque and load disturbances on the driveline, as shown in fig. 8. If no active torque compensation measures are taken, the natural decay of the rotational speed jitter will last longer, and the rotational speed jitter can be well suppressed after the torque compensation method of the present invention is adopted, and the result is shown in fig. 9. Therefore, the electric vehicle shake suppression method can effectively suppress electric vehicle shake, so that riding comfort is improved, and working performance and service life of a transmission system are improved.
In summary, the electric vehicle shake suppression device provided by the embodiment of the invention can effectively suppress the rotational speed shake of the electric vehicle, thereby improving the riding comfort of the electric vehicle and improving the working performance and the service life of a transmission system.
Fig. 11 is a block diagram of an electric vehicle according to an embodiment of the present invention.
As shown in fig. 11, the electric vehicle 1000 includes the electric vehicle restraint device 100 in the above embodiment.
According to the electric vehicle disclosed by the embodiment of the invention, through the restraining device in the embodiment, the rotating speed shake of the electric vehicle can be effectively restrained, so that the riding comfort of the electric vehicle is improved, and meanwhile, the working performance and the service life of a transmission system can be improved.
In addition, other structures and functions of the electric vehicle according to the embodiments of the present invention are known to those skilled in the art, and are not described herein for redundancy reduction.
In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, the different embodiments or examples described in this specification and the features of the different embodiments or examples may be combined and combined by those skilled in the art without contradiction.
Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present invention, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise.
Any process or method descriptions in flow charts or otherwise described herein may be understood as representing modules, segments, or portions of code which include one or more executable instructions for implementing specific logical functions or steps of the process, and additional implementations are included within the scope of the preferred embodiment of the present invention in which functions may be executed out of order from that shown or discussed, including substantially concurrently or in reverse order from that shown or discussed, depending on the functionality involved, as would be understood by those reasonably skilled in the art of the embodiments of the present invention.
Logic and/or steps represented in the flowcharts or otherwise described herein, e.g., a ordered listing of executable instructions for implementing logical functions, can be embodied in any computer-readable medium for use by or in connection with an instruction execution system, apparatus, or device, such as a computer-based system, processor-containing system, or other system that can fetch the instructions from the instruction execution system, apparatus, or device and execute the instructions. For the purposes of this description, a "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of the computer-readable medium would include the following: an electrical connection (electronic device) having one or more wires, a portable computer diskette (magnetic device), a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disc read-only memory (CDROM). In addition, the computer readable medium may even be paper or other suitable medium on which the program is printed, as the program may be electronically captured, via, for instance, optical scanning of the paper or other medium, then compiled, interpreted or otherwise processed in a suitable manner, if necessary, and then stored in a computer memory.
It is to be understood that portions of the present invention may be implemented in hardware, software, firmware, or a combination thereof. In the above-described embodiments, the various steps or methods may be implemented in software or firmware stored in a memory and executed by a suitable instruction execution system. As with the other embodiments, if implemented in hardware, may be implemented using any one or combination of the following techniques, as is well known in the art: discrete logic circuits having logic gates for implementing logic functions on data signals, application specific integrated circuits having suitable combinational logic gates, programmable Gate Arrays (PGAs), field Programmable Gate Arrays (FPGAs), and the like.
Those of ordinary skill in the art will appreciate that all or a portion of the steps carried out in the method of the above-described embodiments may be implemented by a program to instruct related hardware, where the program may be stored in a computer readable storage medium, and where the program, when executed, includes one or a combination of the steps of the method embodiments.
In addition, each functional unit in the embodiments of the present invention may be integrated in one processing module, or each unit may exist alone physically, or two or more units may be integrated in one module. The integrated modules may be implemented in hardware or in software functional modules. The integrated modules may also be stored in a computer readable storage medium if implemented in the form of software functional modules and sold or used as a stand-alone product.
The above-mentioned storage medium may be a read-only memory, a magnetic disk or an optical disk, or the like. While embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and not to be construed as limiting the invention, and that variations, modifications, alternatives and variations may be made to the above embodiments by one of ordinary skill in the art within the scope of the invention.
In the present invention, unless expressly stated or limited otherwise, a first feature "up" or "down" a second feature may be the first and second features in direct contact, or the first and second features in indirect contact via an intervening medium. Moreover, a first feature being "above," "over" and "on" a second feature may be a first feature being directly above or obliquely above the second feature, or simply indicating that the first feature is level higher than the second feature. The first feature being "under", "below" and "beneath" the second feature may be the first feature being directly under or obliquely below the second feature, or simply indicating that the first feature is less level than the second feature.
While embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and not to be construed as limiting the invention, and that variations, modifications, alternatives and variations may be made to the above embodiments by one of ordinary skill in the art within the scope of the invention.

Claims (10)

1. The method for suppressing the jitter of the electric automobile is characterized by comprising the following steps of:
acquiring the motor rotating speed of the electric automobile;
continuously performing second-order filtering processing on the motor rotating speed for two times to obtain rotating speed jitter, wherein the first second-order filtering processing is performed by adopting a first second-order band-pass filter, the second-order filtering processing is performed by adopting a second-order band-pass filter, and the center frequency of the first second-order band-pass filter and the center frequency of the second-order band-pass filter are rotating speed jitter frequencies determined according to the motor rotating speed;
generating a torque compensation value according to the rotational speed jitter amount;
and superposing the torque compensation value with a given torque to restrain the electric automobile from shaking.
2. The electric-vehicle vibration suppression method of claim 1, wherein a bandwidth of the first second-order bandpass filter is determined based on a center frequency of the first second-order bandpass filter, and a bandwidth of the second-order bandpass filter is determined based on a center frequency of the second-order bandpass filter.
3. The electric vehicle vibration suppression method according to claim 2, characterized in that the motor rotation speed is subjected to two successive second order filtering processes by the following formula:
Figure FDA0004072538550000011
wherein G is s B is a transfer function 1 For the bandwidth of the first second order band pass filter, B 2 For the bandwidth of the second order band-pass filter, s is Laplacian, omega 0 And the center frequency of the first second-order band-pass filter and the center frequency of the second-order band-pass filter are rotation speed jitter frequencies determined according to the rotation speed of the motor.
4. The electric vehicle vibration suppression method according to claim 3, wherein the torque compensation value is obtained by multiplying the rotational speed vibration amount by a gain coefficient, wherein the gain coefficient obtaining step includes:
setting the center frequency at which the bandwidths of the first second-order band-pass filter and the second-order band-pass filter are twice;
the initial value of the gain factor is calculated by the following formula:
K 0 ＝0.5*ΔTe/Am，
wherein K is 0 For the initial value of the gain factor, Δte=te 1 -Te 0 Te is the torque variation amount at the time of given torque abrupt change 1 Te for the abrupt given torque 0 For the given torque before abrupt change, am is the amplitude of the cross variable obtained after the first second-order band-pass filter and the second-order band-pass filter are cascaded for the obtained motor rotating speed when the torque compensation value is not overlapped with the given torque;
and adjusting the initial value of the gain coefficient to enable the jitter amplitude of the motor rotating speed to be in a first preset range.
5. The electric-vehicle shake suppression method according to claim 3, wherein the second-order band-pass filter has a bandwidth twice the center frequency, and the first-order band-pass filter has a bandwidth that is acquired by:
setting the central frequency of which the bandwidth initial value of the first second-order band-pass filter is twice;
after the torque compensation value is overlapped with the given torque, acquiring the adjustment time of the output of the first second-order band-pass filter and the output of the second-order band-pass filter after cascading, and acquiring the direct current bias of the torque obtained after the torque compensation value is overlapped with the given torque;
and adjusting the initial value of the bandwidth of the first second-order band-pass filter so as to enable the adjusting time to be in a second preset range and enable the direct current bias to be in a third preset range.
6. A computer-readable storage medium, on which a computer program is stored, characterized in that the computer program, when executed by a processor, implements the electric vehicle shake suppression method according to any one of claims 1 to 5.
7. An electric vehicle shake suppression device, characterized by comprising:
the acquisition module is used for acquiring the motor rotating speed of the electric automobile;
the filtering module is used for continuously performing second-order filtering processing on the motor rotating speed for two times to obtain rotating speed jitter, wherein the filtering module comprises a first second-order band-pass filter and a second-order band-pass filter which are cascaded, and the center frequency of the first second-order band-pass filter and the center frequency of the second-order band-pass filter are rotating speed jitter frequencies determined according to the motor rotating speed;
the generation module is used for generating a torque compensation value according to the rotation speed jitter quantity;
and the control module is used for superposing the torque compensation value with a given torque so as to inhibit the shake of the electric automobile.
8. The electric-vehicle vibration suppression device of claim 7, wherein a bandwidth of the first second-order bandpass filter is determined based on a center frequency of the first second-order bandpass filter, and a bandwidth of the second-order bandpass filter is determined based on a center frequency of the second-order bandpass filter.
9. The apparatus for suppressing vibration of an electric vehicle according to claim 8, wherein the filter module performs the second order filter process on the motor rotation speed twice in succession by the following formula:
Figure FDA0004072538550000021
wherein G is s B is a transfer function 1 For the bandwidth of the first second order band pass filter, B 2 For the bandwidth of the second order band-pass filter, s is Laplacian, omega 0 And the center frequency of the first second-order band-pass filter and the center frequency of the second-order band-pass filter are rotation speed jitter frequencies determined according to the rotation speed of the motor.
10. An electric vehicle characterized by comprising the electric vehicle shake suppression apparatus according to any one of claims 7 to 8.
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