Motor Torque Zero-Crossing Control Method, System, Medium and Device

Abstract

The present invention provides a method, system, medium and device for controlling the motor torque to pass through zero, including: when the vehicle is in a coasting state, the torque is negative, and first-order filtering is adopted in the positive braking area; when the torque control enters the positive zero-crossing area, parabolic filtering is adopted to gradually reduce the increasing speed of the torque near zero; when entering the positive acceleration area, second-order filtering is adopted; when the vehicle is in a driving state and the accelerator pedal is released, first-order filtering is adopted when in the negative deceleration area; when entering the negative zero-crossing area, parabolic filtering is adopted; when entering the negative braking area, first-order filtering is adopted to quickly respond to the torque demand. After filtering by the present invention, the motor speed is stable, the power response only becomes slow in the zero-crossing area, and the driver's torque request can be quickly responded in other areas. Moreover, the motor jitter can be effectively controlled under various working conditions, and the vehicle drivability is smooth.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle motor torque control, and specifically, to a motor torque zero-crossing control method, system, medium and device. Background Art

[0002] For new energy vehicles, especially pure electric vehicles, there is a gap between the motor and the gears of the reducer, and there is no buffer element similar to a shock absorber. If the vehicle accelerates or decelerates suddenly, since the motor torque has a zero-crossing situation at this time, it will be found that the vehicle shakes and is accompanied by the noise of gear knocking, which seriously affects the comfort and smoothness of the vehicle. Therefore, the zero-crossing control of the motor torque is very important.

[0003] Patent document CN107117069A (application number: CN201710269017.0) discloses an electric vehicle motor torque zero-crossing control method, which adopts a zero-crossing holding control strategy for the motor torque by presetting a demand torque zero-crossing interval [X, -X].

[0004] Currently, the control methods for motor torque zero-crossing are mainly divided into two categories. One is to smooth the torque demand. This method can only suppress the jitter of the motor torque zero-crossing to a certain extent and cannot completely eliminate it. The other is to change the rising or falling rate of the torque demand. This method will affect the dynamic response performance of the entire acceleration or deceleration process, and the impact will also increase as the vehicle wear gap increases. Summary of the Invention

[0005] Aiming at the defects in the prior art, the purpose of the present invention is to provide a motor torque zero-crossing control method, system, medium and device.

[0006] According to the motor torque zero-crossing control method provided by the present invention, it includes:

[0007] When the vehicle is in a coasting state and the torque is negative, and the accelerator pedal is depressed at this time, the torque gradually increases. If the torque value has not exceeded the preset second threshold, it is recorded as the positive braking area and first-order filtering is adopted; when the torque continues to increase and exceeds the preset second threshold, the torque control enters the positive zero-crossing area. At this time, the motor speed is close to 0, and parabolic filtering is adopted to gradually reduce the increasing speed of the torque near zero; when the torque exceeds the preset first threshold and enters the positive acceleration area, second-order filtering is adopted to ensure that the filtered torque follows the demand torque;

[0008] When the accelerator pedal is released during vehicle driving, if the torque gradually decreases but is still greater than the preset third threshold, it is in the negative deceleration zone and first-order filtering is adopted; if the torque continues to decrease below the preset third threshold and enters the negative zero-crossing zone, at this time the motor speed is close to 0, and parabolic filtering is adopted; when the torque crosses zero and is lower than the preset fourth threshold, it enters the negative braking zone and first-order filtering is used to quickly respond to torque requirements.

[0009] Preferably, the time-domain expression of the first-order filtering is:

[0010]

[0011] where y old represents the output value of the previous stage; x in represents the input value; T represents the filtering coefficient, and the larger the value, the slower the torque response speed; y represents the output torque value.

[0012] Preferably, the time-domain expression of the parabolic filtering is:

[0013]

[0014] where M delta represents the distance from the zero-torque point; y old represents the output value of the previous stage; T represents the filtering coefficient, and the larger the value, the slower the torque response speed; y represents the output torque value.

[0015] Preferably, the time-domain expression of the second-order filtering is:

[0016]

[0017]

[0018] where F damp represents the damping coefficient of the second-order filtering; y old represents the output value of the previous stage; T represents the filtering coefficient, and the larger the value, the slower the torque response speed; y represents the output torque value; x in represents the input value; y1 is an intermediate variable calculated.

[0019] According to the motor torque zero-crossing control system provided by the present invention, it includes:

[0020] When the vehicle is in the coasting state, the torque is negative. At this time, when the accelerator pedal is depressed, the torque gradually increases. If the torque value has not exceeded the preset second threshold, it is recorded as the positive braking area and first-order filtering is adopted; when the torque continues to increase and exceeds the preset second threshold, the torque control enters the positive zero-crossing area. At this time, the motor speed is close to 0, and parabolic filtering is used to gradually reduce the increasing speed of the torque near zero; when the torque exceeds the preset first threshold and enters the positive acceleration area, second-order filtering is adopted to ensure that the filtered torque follows the required torque.

[0021] When the accelerator pedal is released during the vehicle driving state, the torque gradually decreases but is still greater than the preset third threshold, then it is in the negative deceleration area and first-order filtering is adopted; when the torque continues to decrease and is lower than the preset third threshold, it enters the negative zero-crossing area. At this time, the motor speed is close to 0 and parabolic filtering is adopted; when the torque crosses zero and is lower than the preset fourth threshold, it enters the negative braking area and first-order filtering is used to quickly respond to the torque demand.

[0022] Preferably, the time-domain expression of the first-order filtering is:

[0023]

[0024] where y old represents the output value of the previous stage; x in represents the input value; T represents the filtering coefficient, and the larger the value, the slower the torque response speed; y represents the output torque value.

[0025] Preferably, the time-domain expression of the parabolic filtering is:

[0026]

[0027] where M delta represents the distance from the zero-torque point; y old represents the output value of the previous stage; T represents the filtering coefficient, and the larger the value, the slower the torque response speed; y represents the output torque value.

[0028] Preferably, the time-domain expression of the second-order filtering is:

[0029]

[0030]

[0031] where F damp represents the damping coefficient of the second-order filtering; y old represents the output value of the previous stage; T represents the filtering coefficient, and the larger the value, the slower the torque response speed; y represents the output torque value; x in represents the input value; y1 is the calculated intermediate variable.

[0032] A computer-readable storage medium storing a computer program according to the present invention, when the computer program is executed by a processor, implements the steps of the motor torque zero-crossing control method described above.

[0033] An electronic device according to the present invention includes a memory, a processor, and a computer program stored on the memory and executable on the processor. When the computer program is executed by the processor, it implements the steps of the motor torque zero-crossing control method described above.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] After filtering using the present invention, the motor speed is stable. Only in the zero-crossing area does the power response slow down, and in other areas, it can quickly respond to the driver's torque request. Moreover, the motor jitter can be effectively controlled under various working conditions, and the vehicle drivability is smooth. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] By reading the detailed description of the non-limiting embodiments with reference to the following drawings, other features, objectives, and advantages of the present invention will become more apparent:

[0037] Figure 1 It is a schematic diagram of torque partitioning;

[0038] Figure 2 It is an actual test effect diagram. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0039] The present invention will be described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several changes and improvements can still be made. These all fall within the protection scope of the present invention.

[0040] Embodiment 1:

[0041] As Figure 1 , the present invention provides a motor torque zero-crossing control method, including the following steps:

[0042] When the vehicle is in a coasting state, the torque is negative. At this time, when a throttle pedal is depressed to a certain opening, the torque gradually increases. Before it exceeds the second threshold, it is recorded as the positive braking area, and first-order filtering is used; when the torque continues to increase and exceeds the second threshold, the torque control enters the positive zero-crossing area. At this time, the motor speed is relatively close to 0, so parabolic filtering needs to be used to gradually reduce the increasing speed of the torque near zero to avoid causing motor jitter; when the torque exceeds the second threshold, second-order filtering is used to ensure that the filtered torque can quickly follow the required torque.

[0043] When the vehicle is in a driving state, release the accelerator pedal. The torque gradually decreases but is still greater than the third threshold and is in the negative deceleration zone, and first-order filtering is adopted; when the torque continues to decrease below the third threshold and enters the negative zero-crossing zone, at this time the motor speed is relatively close to 0. In order to reduce the torque change rate, parabolic filtering is adopted; when the torque crosses zero and is below the fourth threshold, it enters the negative braking zone, and first-order filtering can be used to quickly respond to torque requirements.

[0044] Acceleration and deceleration identification: Determine whether it is accelerating or decelerating according to the magnitude and change gradient of the torque.

[0045] According to the magnitude of the required torque, the torque during the acceleration and deceleration processes is divided into six zones: positive braking, positive zero-crossing, positive acceleration, negative deceleration, negative zero-crossing, and negative braking.

[0046] Establish the filtering time-domain expression:

[0047] The first-order filtering time-domain expression is:

[0048]

[0049] Among them, y old represents the output value of the previous stage; x in represents the input value; T represents the filtering coefficient, and the larger the value, the slower the torque response speed; y represents the output torque value.

[0050] The parabolic filtering time-domain expression is:

[0051]

[0052] Among them, M delta represents the distance from the zero-torque point, that is, Figure 1 the absolute value of the four thresholds in;

[0053] The second-order filtering time-domain expression is:

[0054]

[0055]

[0056] Among them, F damp represents the damping coefficient of the second-order filtering.

[0057] Match the filtering with the torque partition, and different filters are used in different regions. Parabolic filtering is used in the positive zero-crossing and negative zero-crossing zones, second-order filtering is used in the positive acceleration zone, and first-order filtering is used in the positive braking, negative deceleration, and negative braking zones. As Figure 2, which is the actual test effect diagram. After filtering with the present invention, the motor speed is stable. Only the dynamic response becomes slower in the zero-crossing area, and the driver's torque request can be quickly responded to in other areas. Moreover, the motor jitter can be effectively controlled under various working conditions, and the vehicle drivability is smooth.

[0058] Embodiment 2:

[0059] The present invention also provides a motor torque zero-crossing control system, which can be realized by executing the process steps of the motor torque zero-crossing control method. That is, those skilled in the art can understand the motor torque zero-crossing control method as the preferred embodiment of the motor torque zero-crossing control system.

[0060] According to the motor torque zero-crossing control system provided by the present invention, it includes:

[0061] When the vehicle is in a coasting state, the torque is negative. At this time, when the accelerator pedal is depressed, the torque gradually increases. If the torque value has not exceeded the preset second threshold, it is recorded as the positive braking area and first-order filtering is adopted; when the torque continues to increase and exceeds the preset second threshold, the torque control enters the positive zero-crossing area. At this time, the motor speed is close to 0, and parabolic filtering is used to gradually reduce the increasing speed of the torque near zero; when the torque exceeds the preset first threshold, second-order filtering is adopted to ensure that the filtered torque follows the required torque;

[0062] When the accelerator pedal is released during the vehicle driving state, the torque gradually decreases but is still greater than the preset third threshold, then it is in the negative deceleration area and first-order filtering is adopted; when the torque continues to decrease and is lower than the preset third threshold, it enters the negative zero-crossing area. At this time, the motor speed is close to 0, and parabolic filtering is used; when the torque crosses zero and is lower than the preset fourth threshold, it enters the negative braking area and first-order filtering is adopted to quickly respond to the torque demand.

[0063] The time-domain expression of the first-order filtering is:

[0064]

[0065] where y old represents the output value of the previous stage; x in represents the input value; T represents the filtering coefficient, and the larger the value, the slower the torque response speed; y represents the output torque value.

[0066] The time-domain expression of the parabolic filtering is:

[0067]

[0068] where M delta represents the distance from the zero-torque point; y oldrepresents the output value of the previous stage; T represents the filtering coefficient, and the larger the value, the slower the torque response speed; y represents the output torque value.

[0069] The time-domain expression of the second-order filtering is:

[0070]

[0071]

[0072] Among them, F damp represents the damping coefficient of the second-order filtering; y old represents the output value of the previous stage; T represents the filtering coefficient, and the larger the value, the slower the torque response speed; y represents the output torque value; x in represents the input value; y1 is an intermediate variable for calculation.

[0073] Those skilled in the art know that in addition to implementing the systems, devices, and their respective modules provided by the present invention in the form of pure computer-readable program codes, the method steps can be logically programmed to enable the systems, devices, and their respective modules provided by the present invention to be implemented in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers, etc., to achieve the same program. Therefore, the systems, devices, and their respective modules provided by the present invention can be regarded as a kind of hardware component, and the modules included therein for implementing various programs can also be regarded as the structures within the hardware component; the modules for implementing various functions can also be regarded as either software programs for implementing the methods or the structures within the hardware component.

[0074] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Without conflict, the embodiments of the present application and the features in the embodiments can be combined arbitrarily with each other.

Claims

1. A method for controlling the zero crossing of motor torque, characterized in that, Including: When the vehicle is in a coasting state, the torque is negative. At this time, when the accelerator pedal is depressed, the torque gradually increases. If the torque value has not exceeded the preset second threshold, it is recorded as the positive braking area and first-order filtering is adopted; When the torque continues to increase and exceeds the preset second threshold, the torque control enters the positive zero-crossing area. At this time, the motor speed is close to 0, and parabolic filtering is used to gradually reduce the increasing speed of the torque near zero; when the torque exceeds the preset first threshold and enters the positive acceleration area, second-order filtering is adopted to ensure that the filtered torque follows the required torque; When the accelerator pedal is released during the vehicle driving state, the torque gradually decreases but is still greater than the preset third threshold, then it is in the negative deceleration area and first-order filtering is adopted; when the torque continues to decrease below the preset third threshold, it enters the negative zero-crossing area. At this time, the motor speed is close to 0, and parabolic filtering is used; when the torque crosses zero and is lower than the preset fourth threshold, it enters the negative braking area and first-order filtering is adopted to quickly respond to the torque demand.

2. The method for controlling the zero crossing of motor torque according to claim 1, characterized in that, The time-domain expression of the first-order filtering is: Among them, y old represents the output value of the previous stage; x in represents the input value; T represents the filtering coefficient, and the larger the value, the slower the torque response speed; y represents the output torque value.

3. The method for controlling the zero crossing of motor torque according to claim 1, characterized in that, The time-domain expression of the parabolic filtering is: Among them, M delta represents the distance from the zero torque point; y old represents the output value of the previous stage; T represents the filtering coefficient, and the larger the value, the slower the torque response speed; y represents the output torque value.

4. The method for controlling the zero crossing of motor torque according to claim 1, characterized in that, The time-domain expression of the second-order filtering is: Among them, F damp represents the damping coefficient of the second-order filter; y old represents the output value of the previous stage; T represents the filter coefficient, and the larger the value, the slower the torque response speed; y represents the output torque value; x in represents the input value; y1 is the calculated intermediate variable.

5. A control system for the zero crossing of motor torque, characterized in that, Including: When the vehicle is in a coasting state, the torque is negative. At this time, when the accelerator pedal is depressed, the torque gradually increases. If the torque value has not exceeded the preset second threshold, it is recorded as the positive braking area and first-order filtering is adopted; When the torque continues to increase and exceeds the preset second threshold, the torque control enters the positive zero-crossing area. At this time, the motor speed is close to 0, and parabolic filtering is used to gradually reduce the increasing speed of the torque near zero; when the torque exceeds the preset first threshold and enters the positive acceleration area, second-order filtering is adopted to ensure that the filtered torque follows the required torque; When the accelerator pedal is released during the vehicle driving state, the torque gradually decreases but is still greater than the preset third threshold, then it is in the negative deceleration area and first-order filtering is adopted; when the torque continues to decrease below the preset third threshold, it enters the negative zero-crossing area. At this time, the motor speed is close to 0, and parabolic filtering is used; when the torque crosses zero and is lower than the preset fourth threshold, it enters the negative braking area and first-order filtering is adopted to quickly respond to the torque demand.

6. The control system for the zero crossing of motor torque according to claim 5, characterized in that, The time-domain expression of the first-order filtering is: Among them, y old represents the output value of the previous stage; x in represents the input value; T represents the filtering coefficient, and the larger the value, the slower the torque response speed; y represents the output torque value.

7. The control system for the zero crossing of motor torque according to claim 5, characterized in that, The time-domain expression of the parabolic filtering is: Among them, M delta represents the distance from the zero torque point; y old represents the output value of the previous stage; T represents the filtering coefficient, and the larger the value, the slower the torque response speed; y represents the output torque value.

8. The control system for the zero crossing of motor torque according to claim 5, characterized in that, The time-domain expression of the second-order filtering is: Among them, F damp represents the damping coefficient of the second-order filter; y old represents the output value of the previous stage; T represents the filter coefficient, and the larger the value, the slower the torque response speed; y represents the output torque value; x in represents the input value; y1 is the calculated intermediate variable.

9. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by a processor, it implements the steps of the motor torque zero-crossing control method described in any one of claims 1 to 4.

10. An electronic device, comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, When the computer program is executed by a processor, it implements the steps of the motor torque zero-crossing control method described in any one of claims 1 to 4.

Images