CN112977084B

CN112977084B - Motor excitation control method and device for automobile, vehicle and storage medium

Info

Publication number: CN112977084B
Application number: CN202110191852.3A
Authority: CN
Inventors: 黄树毅; 王飞; 杨鹏
Original assignee: Guangzhou Xiaopeng Motors Technology Co Ltd; Guangzhou Chengxingzhidong Automotive Technology Co., Ltd
Current assignee: Guangzhou Xiaopeng Motors Technology Co Ltd; Guangzhou Chengxingzhidong Automotive Technology Co., Ltd
Priority date: 2021-02-19
Filing date: 2021-02-19
Publication date: 2022-08-19
Anticipated expiration: 2041-02-19
Also published as: CN112977084A

Abstract

The embodiment of the application provides a motor excitation control method and device for an automobile, the automobile and a storage medium, wherein the motor excitation control method for the automobile comprises the steps of obtaining the required torque of a motor; when the required torque is zero torque, acquiring the duration of the zero torque of the required torque; if the duration reaches the preset duration threshold, reducing the exciting current of the motor from the normal current value to the preset current value when the duration reaches the preset duration threshold; and if the duration does not reach the preset duration threshold, maintaining the normal current value of the exciting current unchanged. The motor excitation control method for the automobile, provided by the embodiment of the application, can reduce the loss of generated excitation current when the required torque is zero, thereby saving energy and improving the cruising ability of the electric automobile.

Description

Motor excitation control method and device for automobile, vehicle and storage medium

Technical Field

The present application relates to the field of automotive technologies, and in particular, to a motor excitation control method and apparatus for an automobile, a vehicle, and a storage medium.

Background

At present, in an application scenario of an electric vehicle, a motor controller controls a motor to start to work after a driver puts into gear. At the moment, the motor controller controls and outputs corresponding exciting current according to the instruction value output by the exciting current setting module, and then a magnetic field is established in the motor so as to prepare for outputting torque at any time. In this case, the motor controller outputs the field current even if the torque value requested by the vehicle control unit is zero. And the continuous generation of the exciting current can cause the continuous loss of the motor, thereby influencing the cruising ability of the electric automobile.

Disclosure of Invention

In view of the above problems, embodiments of the present application provide a motor excitation control method and apparatus for an automobile, a vehicle, and a storage medium, which can reduce a loss of an excitation current when a required torque is zero, thereby saving energy and improving a cruising ability of an electric automobile.

The embodiment of the application is realized by adopting the following technical scheme:

in a first aspect, some embodiments of the present application provide a motor excitation control method for an automobile, the method including obtaining a required torque of a motor; when the required torque is zero torque, acquiring the duration of the zero torque of the required torque; if the duration reaches the preset duration threshold, reducing the exciting current of the motor from the normal current value to the preset current value when the duration reaches the preset duration threshold; and if the duration does not reach the preset duration threshold, maintaining the normal current value of the exciting current unchanged.

In a second aspect, some embodiments of the present application further provide a motor excitation control device for an automobile, where the device includes a torque acquisition module, a duration acquisition module, a first control module, and a second control module, where the torque acquisition module is configured to acquire a required torque of a motor; the duration acquisition module is used for acquiring the duration of zero torque of the required torque when the required torque is zero torque; the first control module is used for reducing the exciting current of the motor from a normal current value to a preset current value when the duration reaches a preset duration threshold value if the duration reaches the preset duration threshold value; the second control module is used for maintaining the normal current value of the exciting current unchanged if the duration does not reach the preset duration threshold.

In a third aspect, some embodiments of the present application further provide a vehicle including a vehicle body and the motor excitation control method of the automobile as described above, provided in the vehicle body.

In a fourth aspect, the present application further provides a computer-readable storage medium, which stores program codes, wherein the program codes, when executed by a processor, perform the motor excitation control method of the automobile.

The method comprises the steps of obtaining the required torque of a motor; when the required torque is zero torque, acquiring the duration of the zero torque of the required torque; if the duration reaches the preset duration threshold, reducing the exciting current of the motor from the normal current value to the preset current value when the duration reaches the preset duration threshold; if the duration does not reach the preset duration threshold, the normal current value of the exciting current is maintained unchanged, and further the loss of the exciting current can be reduced when the required torque is zero, so that the energy is saved, and the cruising ability of the electric automobile is improved.

These and other aspects of the present application will be more readily apparent from the following description of the embodiments.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

Fig. 1 shows a schematic flowchart of a motor excitation control method of an automobile according to an embodiment of the present application.

Fig. 2 shows a diagram of the field current versus the motor speed.

Fig. 3 shows a schematic flowchart of another excitation control method for a motor of an automobile according to an embodiment of the present application.

Fig. 4 shows a schematic flow chart of step S210 in fig. 3.

Fig. 5 shows another schematic flow chart of step S210 in fig. 3.

Fig. 6 shows a schematic flowchart of a motor excitation control method for another automobile according to an embodiment of the present application.

Fig. 7 shows a schematic flowchart of a motor excitation control method for an automobile according to another embodiment of the present application.

Fig. 8 shows a block diagram of an excitation control device of an automobile according to an embodiment of the present application.

FIG. 9 shows a block diagram of a vehicle according to an embodiment of the present application.

Fig. 10 illustrates a block diagram of a computer-readable storage medium according to an embodiment of the present application.

Detailed Description

Reference will now be made in detail to the embodiments of the present application, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary only for the purpose of explaining the present application and are not to be construed as limiting the present application.

The current three-phase asynchronous motor is one of the driving motor types commonly used by the current electric automobile. In order to achieve good control performance, a vector control mode is generally applied to control a three-phase asynchronous motor. The principle of vector control of the asynchronous motor is mainly as follows: the phase current of the three-phase asynchronous motor can be divided into a D-axis current Id and a Q-axis current Iq through vector decomposition, wherein the Id is used for establishing a magnetic field to generate a magnetic linkage, and the Iq is used for generating electromagnetic torque. The vehicle control unit sends a request torque value to the motor controller, after the motor controller receives the request torque value, the corresponding Q-axis current Iq can be obtained through calculation or a calibration table checking mode, and the subsequent regulators are used for controlling the motor to finally output the specified torque; the exciting current setting module calculates the current D-axis current Id in real time according to information such as the current motor rotating speed, generally, the D-axis current Id is fixed when the motor rotating speed is lower than the rated rotating speed, the D-axis current Id is the rated exciting current of the motor, the D-axis current Id needs to be subjected to field weakening control when the rotating speed is higher than the rated rotating speed, and the D-axis current Id can gradually decrease along with the increase of the rotating speed.

In the application scene of the three-phase asynchronous motor in the electric automobile, when a driver puts into gear, a motor controller controls the motor to start working. At the moment, the motor controller controls and outputs corresponding exciting current according to the instruction value output by the exciting current setting module, and then a magnetic field is established in the motor so as to prepare for outputting torque at any time. In this case, the motor controller outputs the field current even if the torque value requested by the vehicle control unit is zero. And the continuous generation of the exciting current can cause the continuous loss of the motor, thereby influencing the cruising ability of the electric automobile.

The traditional strategy for solving the above problems is: when the torque value requested by the vehicle controller is zero, the motor controller cancels the output of exciting current; when the torque value requested by the whole vehicle controller is not zero, the motor controller outputs the exciting current again. The traditional solution strategy needs to frequently cancel and rebuild the exciting current, and because the motor needs to establish a magnetic field first to output the torque, the traditional solution strategy can reduce the torque responsiveness.

In order to solve the above problems, the inventors have made long-term studies to propose a motor excitation control method, device, vehicle, and storage medium for an automobile in the embodiments of the present application, by acquiring a required torque of a motor; when the required torque is zero torque, acquiring the duration of the zero torque of the required torque; if the duration reaches the preset duration threshold, reducing the exciting current of the motor from the normal current value to the preset current value when the duration reaches the preset duration threshold; if the duration does not reach the preset duration threshold, the normal current value of the exciting current is maintained unchanged, and then the loss of the exciting current can be reduced when the required torque is zero, so that the energy is saved, the cruising ability of the electric automobile is improved, and meanwhile, the exciting current is prevented from being frequently cancelled and reestablished when the required torque is not zero, and the timeliness of torque response is ensured.

As shown in fig. 1, fig. 1 schematically illustrates a motor excitation control method 100 of an automobile according to an embodiment of the present application, where the motor excitation control method 100 of the automobile may include the following steps S110 to S140.

Step S110: and acquiring the required torque of the motor.

In this embodiment, the required torque of the electric machine is also the requested torque sent by the vehicle control unit. The required torque of the motor can be continuously obtained after the driver puts into gear.

Step S120: when the required torque is zero torque, the duration during which the required torque is zero torque is acquired.

When the required torque is zero torque, the driver is not stepping on the accelerator, and the whole vehicle has no required torque. As an embodiment, when the required torque is zero torque, the time counting may be started; when the required torque is changed from zero torque to non-zero torque, which means that the requested torque of the whole vehicle is not zero, the timing is terminated. Thus, the duration when the required torque is zero torque can be acquired.

Step S130: and if the duration reaches the preset duration threshold, reducing the exciting current of the motor from the normal current value to the preset current value when the duration reaches the preset duration threshold.

In this embodiment, if the duration when the required torque is zero torque reaches the preset duration threshold, that is, the required torque has not been converted from zero torque to non-zero torque when the preset duration threshold is reached, the timing may be terminated when the preset duration threshold is reached, and the excitation current of the motor is reduced from the normal current value to the preset current value after the timing is terminated.

In general, the field current may be calculated in real time by the field current setting module based on the current motor speed of the vehicle. When the rotating speed of the motor is less than or equal to the rated rotating speed, the exciting current is kept unchanged; when the rotating speed of the motor is greater than the rated rotating speed, the exciting current is reduced along with the increase of the rotating speed of the motor. Specifically, the relationship of the field current to the motor speed may be as shown in fig. 2.

In the embodiment of the present application, the normal current value of the excitation current refers to a current value corresponding to the current motor rotation speed. Since the motor rotation speed of the vehicle may be different between the time counting start time and the time counting end time, the normal current value of the exciting current after the time counting end time may be different from the normal current value of the exciting current at the time of the time counting start time. In this embodiment, if the duration reaches the preset duration threshold, the timing is terminated, and the current value of the exciting current corresponding to the current motor speed is reduced to the preset current value when the timing is terminated.

In a specific implementation scenario, when the excitation current is changed from the non-zero torque to the zero torque, timing is started by taking 2 seconds as a preset duration threshold, and the motor speed at the time of starting timing is n1, where the corresponding normal current value of the excitation current is Id 1. During the time counting, the motor rotation speed is reduced because the required torque is kept at zero torque, and the time counting is ended if the required torque is still at zero torque after the time counting for 2 seconds, wherein the motor rotation speed is n2 at the time of the time counting, and the normal current value of the corresponding exciting current is Id 2. Further, the excitation current is reduced from the normal current value Id2 to the preset current value at this time. It should be noted that, if the motor rotation speed n1 at the start of the timing and the motor rotation speed n2 at the end of the timing are both less than or equal to the rated rotation speed of the motor, the normal current value Id1 of the corresponding excitation current and the normal current value Id2 of the corresponding excitation current may be the same; if the motor rotation speed n1 at the time of starting the timing is greater than the rated rotation speed of the motor, and the motor rotation speed n2 at the time of ending the timing is greater than the rated rotation speed, or the motor rotation speed at the time of ending the timing is less than or equal to the rated rotation speed, the normal current value Id1 of the corresponding excitation current and the normal current value Id2 of the corresponding excitation current may be different.

As an embodiment, the preset current value may be any fixed value. That is, no matter the duration of the zero torque required torque reaches the preset duration threshold, the corresponding normal current value of the exciting current can be reduced from the normal current value to the preset current value. For example, if the duration that the required torque is zero torque reaches the preset duration threshold value, and the corresponding normal current value of the excitation current is Id1, the excitation current may be reduced from the normal current value Id1 to the preset current value Id 0; if the duration of the zero torque of the required torque reaches the preset duration threshold value, and the corresponding normal current value of the excitation current is Id2, the excitation current may be reduced from the normal current value Id1 to the preset current value Id 0. It should be noted that the preset current value may be zero, that is, the normal current value of the excitation current is reduced to zero excitation current.

As another embodiment, the preset current value may be related to a normal current value of the excitation current. Specifically, when the duration of the zero torque demand torque reaches a preset duration threshold, the preset current value to which the zero torque demand torque is required to be reduced is related to the normal current value of the current excitation current. The preset current value may be a percentage of the normal current value of the current excitation current, for example, 10%, 15%, 20% of the normal current value of the current excitation current. That is, the preset current value may be changed following the change of the normal current of the present excitation current. For example, if the duration that the required torque is zero torque reaches the preset duration threshold value, and the corresponding normal current value of the excitation current is Id1, the excitation current may be reduced from the normal current value Id1 to the preset current value Id 1/5; if the duration that the required torque is zero reaches the preset duration threshold value and the corresponding normal current value of the exciting current is Id2, the exciting current can be reduced from the normal current value Id1 to the preset current value Id 2/5.

In the embodiment, when the duration that the required torque is zero torque reaches the preset duration threshold, the exciting current of the motor is reduced to the preset current value from the normal current value, so that the power consumption of a motor system is reduced when the required torque is zero, the energy is saved, and the cruising ability of the electric automobile is improved.

Step S140: and if the duration does not reach the preset duration threshold, maintaining the normal current value of the exciting current unchanged.

In this embodiment, if the duration when the required torque is zero torque does not reach the preset duration threshold, that is, the required torque is converted from zero torque to non-zero torque when the duration does not reach the preset duration threshold, at this time, the timing may be terminated, and the normal current value of the exciting current may be maintained unchanged, that is, the current value of the exciting current corresponding to the current motor rotation speed at the time of finishing the timing is not changed.

In a specific implementation scenario, when the excitation current changes from the non-zero torque to the zero torque, the timing is started by taking 2 seconds as a preset time threshold, the motor torque is n1 at the beginning of the timing, and the corresponding normal current value of the excitation current is Id 1. If the preset time of 2 seconds is not reached, the required torque is changed from zero torque to non-zero torque again, so that the time counting is ended, wherein the required torque is kept to be zero torque during the time counting so that the rotating speed of the motor is reduced, the rotating speed of the motor is n2 at the end of the time counting, the corresponding normal current value of the exciting current is Id2, and then the normal current value Id2 of the exciting current is kept unchanged when the required torque is changed from zero torque to non-zero torque, namely the normal current value Id2 of the exciting current is not changed. It should be noted that, if the motor rotation speed n1 at the start of the timing and the motor rotation speed n2 at the end of the timing are both less than or equal to the rated rotation speed of the motor, the normal current value Id1 of the corresponding excitation current and the normal current value Id2 of the corresponding excitation current may be the same; if the motor rotation speed n1 at the time of starting the timing is greater than the rated rotation speed of the motor, and the motor rotation speed n2 at the time of ending the timing is greater than the rated rotation speed, or the motor rotation speed at the time of ending the timing is less than or equal to the rated rotation speed, the normal current value Id1 of the corresponding excitation current and the normal current value Id2 of the corresponding excitation current may be different.

It will be appreciated that a new cycle may be started for the duration of zero torque demand when the demand torque again transitions from a non-zero torque to zero torque.

In the embodiment, when the duration that the required torque is zero torque does not reach the preset duration threshold, that is, when the required torque is converted from zero torque to non-zero torque, the normal current value of the exciting current is maintained to be unchanged, so that the situation that the exciting current needs to be frequently cancelled and reestablished when the required torque is frequently converted from zero torque to non-zero torque or from non-zero torque to zero torque in a short time is avoided, and the timeliness of torque response is ensured when the required torque is frequently changed.

According to the motor excitation control method for the automobile, the required torque of the motor is obtained; when the required torque is zero torque, acquiring the duration of the zero torque of the required torque; if the duration reaches the preset duration threshold, reducing the exciting current of the motor from the normal current value to the preset current value when the duration reaches the preset duration threshold; if the duration does not reach the preset duration threshold, the normal current value of the exciting current is maintained unchanged, and then the loss of the exciting current can be reduced when the required torque is zero, so that the energy is saved, the cruising ability of the electric automobile is improved, and meanwhile, the exciting current is prevented from being frequently cancelled and reestablished when the required torque is not zero, and the timeliness of torque response is ensured.

As shown in fig. 3, fig. 3 illustrates another motor excitation control method 200 for an automobile, which is provided in the embodiment of the present application.

Step S210: a current driving mode of the vehicle is determined.

The current driving mode of the vehicle may include, but is not limited to, at least one of a first driving mode, a second driving mode, and a third driving mode. In this embodiment, the first driving mode may be an energy-saving driving mode, the second driving mode may be a standard driving mode, and the third driving mode may be a sport driving mode.

Further, in the energy-saving driving mode, the vehicle may be biased toward energy saving; in the standard driving mode, the vehicle can keep the balance of energy-saving and torque response performance; in the sport driving mode, the vehicle may be biased toward torque response performance.

As shown in fig. 4, as one embodiment, the current driving mode of the vehicle may be determined by the following steps S211 to S212.

Step S211: a driving mode signal of the vehicle is acquired.

The driving mode of the vehicle may be set by the vehicle control unit. In the present embodiment, the driving mode signal transmitted from the vehicle control unit can be acquired.

Step S212: the current driving mode of the vehicle is determined from the driving mode signal.

In this embodiment, the current driving mode of the vehicle may be determined according to a driving mode signal transmitted by the vehicle control unit. Specifically, if the driving mode signal sent by the vehicle control unit is an energy-saving driving mode signal, determining that the current driving mode of the vehicle is an energy-saving driving mode; if the driving mode signal sent by the vehicle control unit is a standard driving mode signal, determining that the current driving mode of the vehicle is a standard driving mode; and if the driving mode signal sent by the vehicle control unit is a motion driving mode signal, determining that the current driving mode of the vehicle is a motion driving mode.

As another embodiment, as shown in fig. 5, the current driving mode of the vehicle may be determined by the following steps S213 to S214.

Step S213: the current running data of the vehicle is acquired.

In the present embodiment, the current driving data of the vehicle may include, but is not limited to, at least one of the following data: average power of the motor per unit time, average output torque of the motor per unit time, accelerator depth, and the like.

Step S214: and determining the current driving mode of the vehicle according to the current driving data.

In this embodiment, after the current driving data of the vehicle is acquired, the current driving mode of the vehicle may be determined according to the current driving data.

In some embodiments, the current driving mode of the vehicle may be determined according to any one of an average power of the motor per unit time, an average output torque of the motor per unit time, and a depth of an accelerator. Specifically, when the current driving mode of the vehicle is judged according to the average power of the motor in unit time, if the average power of the motor in unit time is smaller than a first power threshold, the current driving mode of the vehicle can be considered as the energy-saving driving mode; if the average power of the motor in unit time is greater than or equal to the first power threshold and less than the second power threshold, the current driving mode of the vehicle can be considered as a standard driving mode; if the average power of the motor in the unit time is greater than or equal to the second power threshold, the current driving mode of the vehicle can be considered as a sport driving mode. When the current driving mode of the vehicle is judged according to the average output torque of the motor in unit time, if the average output torque of the motor in unit time is smaller than a first torque threshold value, the current driving mode of the vehicle can be considered as an energy-saving driving mode; if the average output torque of the motor in unit time is greater than or equal to the first torque threshold value and less than the second torque threshold value, the current driving mode of the vehicle can be considered as a standard driving mode; if the average output torque of the motor per unit time is greater than or equal to the second torque threshold, the current driving mode of the vehicle may be considered as the sporty driving mode. When the current driving mode of the vehicle is judged according to the accelerator depth, if the accelerator depth is smaller than a first accelerator depth threshold value, the current driving mode of the vehicle can be considered as an energy-saving driving mode; if the accelerator depth is greater than or equal to the first accelerator depth threshold value and less than the second accelerator depth threshold value, the current driving mode of the vehicle can be considered as a standard driving mode; if the throttle depth is greater than or equal to the second throttle depth threshold, the current driving mode of the vehicle can be considered as a sport driving mode.

In some embodiments, the current driving mode of the vehicle may be determined by comprehensively considering at least two data of the average power of the motor per unit time, the average output torque of the motor per unit time, and the accelerator depth. Specifically, each data may be comprehensively calculated with a preset weight, and then the calculation result may be compared with a result threshold value, thereby determining the current driving mode of the vehicle. Taking three data as an example, the average power of the motor in unit time corresponds to a first preset weight, the average output torque of the motor in unit time corresponds to a second preset weight, and the accelerator depth corresponds to a third preset weight. Comprehensively calculating the three data according to the first preset weight, the second preset weight and the third preset weight, and if the calculation result is smaller than a first result threshold value, determining that the current driving mode of the vehicle is an energy-saving driving mode; if the calculation result is greater than or equal to the first result threshold and less than the second result threshold, the current driving mode of the vehicle can be considered as the standard driving mode; if the calculation result is greater than the second result threshold, the current driving mode of the vehicle may be considered as a sporty driving mode.

In the embodiment, after the current driving data of the vehicle is acquired, the current driving mode of the vehicle can be determined according to the current driving data, and the current driving mode of the vehicle can be self-judged, so that the current driving mode of the vehicle can be accurately obtained even if the communication between the vehicle and the vehicle control unit fails.

Step S220: and determining a preset current value according to the current driving mode.

In this embodiment, different driving modes may correspond to different preset current values. The preset current of the energy-saving driving mode can correspond to a first preset current value; the preset current value of the standard driving mode can correspond to a second preset current value and a third preset current value; the preset current value of the sport driving mode may correspond to a fourth preset current value; therefore, when the current driving mode of the vehicle is the energy-saving driving mode, the preset current value may be determined to be the first preset current value; when the current driving mode of the vehicle is the standard driving mode, the preset current value can be determined to be a second preset current value and a third preset current value; when the current driving mode of the vehicle is the sport driving mode, the preset current value may be determined to be a fourth preset current value.

Further, different driving modes may correspond to different excitation current control strategies. As shown in fig. 3, when the current driving mode is the first driving mode, which may be the energy saving driving mode, the field current control strategy in steps S220 to S270 may be performed.

Step S230: and acquiring the required torque of the motor.

Step S240: when the required torque is zero torque, the duration for which the required torque is zero torque is acquired.

In this embodiment, when the required torque is zero torque, it means that the driver does not step on the accelerator, and the entire vehicle has no required torque. As an embodiment, when the required torque is zero torque, the timer may be started; when the required torque is changed from zero torque to non-zero torque, which means that the requested torque of the whole vehicle is not zero, the timing is terminated. Thus, the duration when the required torque is zero torque can be acquired.

Step S250: and judging whether the duration reaches a preset duration threshold value.

In this embodiment, the duration when the required torque is zero torque is timed with the preset duration threshold as the time limit. For example, if the preset time period threshold is 2S, the duration when the required torque is zero torque may be counted up with 2S as a time period.

Further, if the duration reaches the preset duration threshold, that is, the required torque is not converted from zero torque to non-zero torque within the preset duration threshold, at this time, the timing may be terminated when the preset duration threshold is reached, and step S260 is executed. If the duration does not reach the preset duration threshold, that is, the required torque is converted from zero torque to non-zero torque within the preset duration threshold, step S270 may be executed.

In a specific embodiment, assuming that the preset time period threshold is 2S, the timing of 2S may be started when the required torque is changed from the non-zero torque to the zero torque, and if the required torque is still maintained at the zero torque at the end of the timing of 2S, step S260 is executed; if the required torque is changed from zero torque to non-zero torque again during the 2S count, the count is terminated and step S270 is executed.

Step S260: and reducing the excitation current of the motor from the normal current value to a first preset current value.

In this embodiment, if the duration when the required torque is zero torque reaches the preset duration threshold, the exciting current of the motor may be reduced from the normal current value to the first preset current value. For the explanation of the normal current value of the exciting current, reference may be made to the foregoing embodiments, and details are not repeated herein.

In this embodiment, the first preset current value may be zero, that is, when the duration when the required torque is zero torque reaches the preset duration threshold, the exciting current of the motor may be reduced from the normal current value to zero exciting current, so that the power consumption of the motor system when the required torque is zero torque may be maximally reduced, and the cruising ability of the vehicle may be maximally improved.

In some embodiments, the first predetermined current value may also be a fixed value. By setting this fixed value, the cruising ability of the vehicle can be greatly improved.

In some embodiments, the first preset current value may also be a proportion of the normal value of the excitation current, for example, the first preset current value may be 10%, 20%, etc. of the normal current value of the excitation current. Through proper setting of the proportion, the cruising ability of the vehicle can be greatly improved.

Step S270: the normal current value of the exciting current is maintained unchanged.

In this embodiment, if the duration does not reach the preset duration threshold when the required torque is zero torque, the normal current value of the exciting current may be maintained unchanged, so as to avoid frequent switching from zero torque to non-zero torque or switching from non-zero torque to zero torque within the preset duration threshold, which requires frequent cancellation and reconstruction of the exciting current, and further ensure timeliness of torque response when the required torque changes frequently.

In the embodiment, in the energy-saving driving mode, if the duration when the required torque is zero torque reaches the preset duration threshold, the exciting current can be reduced from the normal current value to zero exciting current, so that the energy is saved to the maximum extent, and the cruising ability of the vehicle is improved; if the duration of the zero torque requirement does not reach the preset duration threshold, the normal current value of the exciting current can be maintained unchanged, so that the condition that the required torque is frequently changed from zero torque to non-zero torque or from non-zero torque to zero torque within the preset duration threshold, the exciting current needs to be frequently cancelled and rebuilt is avoided, and the timeliness of torque response is ensured when the required torque is frequently changed. Therefore, in the energy-saving driving mode, the vehicle can ensure certain torque response capacity and simultaneously maximize the cruising capacity.

Further, as shown in fig. 6, when the current driving mode is the second driving mode, which may be the standard driving mode, the field current control strategy in the following steps S280 to S350 may be performed.

Step S280: and acquiring the required torque of the motor.

Step S290: when the required torque is zero torque, a first duration in which the required torque is zero torque is acquired.

In this embodiment, when the required torque is zero torque, it means that the driver does not step on the accelerator, and the entire vehicle has no required torque. As an embodiment, when the required torque is zero torque, the timer may be started; when the required torque is changed from zero torque to non-zero torque, which means that the requested torque of the whole vehicle is not zero, the timing is terminated. Thus, the first duration when the required torque is zero torque can be acquired.

Step S300: and judging whether the first duration reaches a first preset duration threshold value.

In the present embodiment, the first duration when the required torque is zero torque is timed with the first preset duration threshold as a time limit. For example, if the first preset time period threshold is 5S, the first duration in which the required torque is zero torque may be timed with 5S as a time limit.

Further, if the first duration reaches the first preset duration threshold, that is, the required torque is not converted from zero torque to non-zero torque within the first preset duration threshold, at this time, the timing may be terminated when the first preset duration threshold is reached, and step S310 is executed. If the first duration does not reach the first preset duration threshold, that is, the required torque is changed from zero torque to non-zero torque within the first preset duration threshold, step S320 may be executed.

In a specific embodiment, assuming that the first preset time period threshold is 5S, the timing of 5S may be started when the required torque is changed from the non-zero torque to the zero torque, and if the required torque is still maintained at the zero torque at the end of the timing of 5S, step S310 is executed; if the required torque is changed from zero torque to non-zero torque again during the 5S timer, the timer is terminated and step S320 is executed.

Step S310: and reducing the excitation current of the motor from the normal current value to a second preset current value.

In this embodiment, if the first duration when the required torque is zero reaches the first preset duration threshold, the exciting current of the motor may be reduced from the normal current value to the second preset current value. For the explanation of the normal current value of the exciting current, reference may be made to the foregoing embodiments, and details are not repeated herein. It should be noted that, in order to ensure that the exciting current still has a reduction space in the subsequent step, the second preset current value may not be zero.

Further, the second preset current value may be a proportion of the normal current value of the exciting current. For example, the second preset current value may be 40%, 50%, 60%, etc. of the normal current value of the excitation current.

In some embodiments, the second predetermined current value may also be a fixed value.

Further, after the exciting current of the motor is reduced from the normal current value to the second preset current value, the step S330 may be continuously performed.

Step S320: the normal current value of the exciting current is maintained unchanged.

In this embodiment, if the first duration when the required torque is zero does not reach the first preset duration threshold, the normal current value of the exciting current may be maintained unchanged, so as to avoid frequent switching from zero torque to non-zero torque or switching from non-zero torque to zero torque within the first preset duration threshold, which requires frequent cancellation and reconstruction of the exciting current, and further ensure timeliness of torque response when the required torque changes frequently.

Step S330: and judging whether the second duration reaches a second preset duration threshold.

In this embodiment, after the exciting current of the motor is reduced from the normal current value to the second preset current value, it may be continuously determined whether the second duration reaches the second preset duration threshold. Wherein the second duration refers to a duration in which the required torque following the first duration is zero torque. For example, if the first preset time period threshold is 5S and the second duration is 5S, when the required torque is changed from non-zero torque to zero torque, the first 5S timer is started, and if the required torque is still zero torque after the 5S timer ends, the excitation current of the motor is reduced from the normal current value to the second preset current value, and then the second 5S timer is started after the excitation current of the motor is reduced to the second preset current value, and it is determined that the required torque is zero torque and can be maintained for 5S.

Further, the field current of the electric machine is maintained at the second preset current value during the second duration in which the required torque is zero torque. For example, assuming that the second preset current value is 50% of the normal current value of the excitation current, the excitation current of the motor is maintained at 50% of the normal current value during the second duration in which the required torque is zero torque.

Further, if the second duration reaches the second preset duration threshold, that is, the required torque is not converted from zero torque to non-zero torque within the second preset duration threshold, at this time, when the second preset duration threshold reaches, the timing may be terminated, and step S340 is executed. If the second duration does not reach the second preset duration threshold, that is, the required torque is changed from zero torque to non-zero torque within the second preset duration threshold, then step S350 may be executed.

In a specific embodiment, assuming that the second preset duration threshold is 5S, the timing of 5S may be started when the exciting current is reduced from the normal current value to the second preset current value, and if the required torque is still maintained at zero torque at the end of the timing of 5S, step S340 is executed; if the required torque is changed from zero torque to non-zero torque again during the 5S timer, the timer is terminated and step S350 is executed.

Step S340: and reducing the excitation current of the motor from the second preset current value to a third preset current value.

And when the second duration of the zero torque demand torque reaches a second preset duration threshold, reducing the exciting current of the motor from a second preset current value to a third preset current value.

In this embodiment, the third preset current value may be zero, that is, the exciting current of the motor is reduced from the second preset current value to zero exciting current. For example, assuming that the second preset current value is 50% of the normal current value of the excitation current, the excitation current of the motor may be reduced from 50% of the normal current value to zero. In some embodiments, the third predetermined current value may also be a fixed value.

After the exciting current is reduced to zero exciting current, the power consumption when the exciting current is generated is avoided, the energy can be saved, and the endurance mileage of the vehicle is improved.

Step S350: and adjusting the excitation current from a second preset current value to a normal current value.

And when the second duration time of the zero torque of the required torque does not reach a second preset current value, adjusting the exciting current of the motor to a normal current value from the second preset current value. For example, assuming that the second preset current value is 50% of the normal current value of the excitation current, the excitation current of the motor may be readjusted from 50% of the normal current value to the normal current value.

In the embodiment, in a standard driving mode, the duration of zero torque of the required torque is timed twice, if the required torque is converted from zero torque to non-zero torque during the first timing, the normal current value of the exciting current can be kept unchanged, so that frequent cancellation and reconstruction of the exciting current caused by the change of the required torque in a short time can be avoided; if the zero torque is not converted into the non-zero torque from the zero torque during the first timing, the normal current value of the exciting current can be reduced to a second preset current value, the power consumption of the exciting current is properly reduced, and meanwhile, the exciting current is maintained to be the second preset current value, so that the second timing is started when the required torque is the zero torque. If the required torque is converted from zero torque to non-zero torque during the second timing, restoring the exciting current from a second preset current value to a normal current value to realize the quick response of the torque; if the requirement is not changed from zero torque to non-zero torque from zero torque during the second timing, the exciting current can be reduced from the second preset current value to the third preset current value, so that the power consumption for generating the exciting current is further reduced, and a better energy-saving effect is achieved. Therefore, in the standard driving mode, the vehicle can have good cruising ability and torque response ability, and the cruising ability and the torque response ability can reach certain balance.

It is to be noted that, since the balance between the cruising ability and the torque response ability of the vehicle is ensured in the standard driving mode, the first preset time period threshold value and the second preset time period threshold value when the required torque is zero torque in the standard driving mode may be larger than the preset time period threshold value when the required torque is zero torque in the energy-saving driving mode. For example, in the energy-saving driving mode, the preset duration threshold may be 2S; in the standard driving mode, both the first preset duration threshold and the second preset duration threshold may be 5S. And because the first preset duration threshold and the second preset duration threshold in the standard driving mode are larger than the preset duration threshold in the energy-saving driving mode, the torque response capability in the standard driving mode can be further superior to that in the energy-saving driving mode.

Further, as shown in fig. 7, when the current driving mode is the third driving mode, which may be the sport driving mode, the field current control strategy in the following steps S360 to S400 may be performed.

Step S360: and acquiring the required torque of the motor.

Step S370: when the required torque is zero torque, the duration for which the required torque is zero torque is acquired.

In this embodiment, when the required torque is zero torque, it means that the driver does not step on the accelerator, and the entire vehicle has no torque request. As an embodiment, when the required torque is zero torque, the timer may be started; when the required torque is changed from zero torque to non-zero torque, which means that the requested torque of the whole vehicle is not zero, the timing is terminated. Thus, the duration when the required torque is zero torque can be acquired.

Step S380: and judging whether the duration reaches a preset duration threshold or not.

In this embodiment, the duration when the required torque is zero torque is timed with the preset duration threshold as a time limit. For example, if the preset time period threshold is 5S, the duration when the required torque is zero torque may be counted up with 5S as a time limit.

Further, if the duration reaches the preset duration threshold, that is, the required torque is not converted from zero torque to non-zero torque within the preset duration threshold, at this time, the timing may be terminated when the preset duration threshold reaches, and step S390 is executed. If the duration does not reach the preset duration threshold, that is, the required torque is converted from zero torque to non-zero torque within the preset duration threshold, step S400 may be executed.

In a specific embodiment, assuming that the preset time threshold is 5S, the timing of 5S may be started when the required torque is changed from the non-zero torque to the zero torque, and if the required torque is still maintained at the zero torque at the end of the timing of 5S, step S390 is executed; if the required torque is changed from zero torque to non-zero torque again during the 5S count, the count is terminated and step S400 is executed.

Step S390: and when the duration reaches a preset duration threshold, reducing the exciting current of the motor from the normal current value to a fourth preset current value.

In this embodiment, if the duration when the required torque is zero torque reaches the preset duration threshold, the exciting current of the motor may be reduced from the normal current value to a fourth preset current value. For the explanation of the normal current value of the exciting current, reference may be made to the foregoing embodiments, and details are not repeated herein.

In this embodiment, the fourth preset current value may not be zero. Specifically, the fourth preset current value may be a proportion of the excitation current normal current value. For example, the fourth preset current value may be 40%, 50%, 60%, etc. of the excitation current normal current value.

In some embodiments, the fourth predetermined current value may also be a fixed value.

Further, the fourth preset current value in the sport driving mode may be greater than the first preset current value in the energy-saving driving mode. It should be noted that, compared with the energy-saving driving mode in which the excitation current is adjusted from the first preset current value to the normal current value when the subsequent required torque is converted from zero torque to non-zero torque, the motion driving mode in which the excitation current is adjusted from the fourth preset current value to the normal current value when the subsequent required torque is converted from zero torque to non-zero torque enables the torque to respond quickly.

Step S400: the normal current value of the exciting current is maintained unchanged.

In this embodiment, if the duration when the required torque is zero does not reach the preset duration threshold, the normal current value of the exciting current may be maintained unchanged, so as to avoid frequent switching from zero torque to non-zero torque or switching from non-zero torque to zero torque within the preset duration threshold, which requires frequent cancellation and reconstruction of the exciting current, and further ensure timeliness of torque response when the required torque changes frequently.

In this embodiment, in the motion driving mode, if the duration when the required torque is zero torque reaches the preset duration threshold, the excitation current may be reduced from the normal current value to a fourth preset current value, so as to save energy and improve the cruising ability of the vehicle, and meanwhile, if the required torque is subsequently converted from zero torque to non-zero torque, the excitation current may be converted from the fourth preset current value to the normal current value, so that the torque responds quickly; if the duration of the zero torque demand does not reach the preset duration threshold, the normal current value of the exciting current can be maintained unchanged, so that the exciting current is prevented from being frequently cancelled and reestablished when the zero torque demand is frequently converted into the non-zero torque or the non-zero torque demand is frequently converted into the zero torque within the preset duration threshold, and the timeliness of torque response is guaranteed when the torque demand is frequently changed. It follows that in the sport driving mode, the vehicle is able to guarantee maximization of the torque response capability while maintaining a certain cruising capability.

It is to be noted that, since the torque response capability of the vehicle is maximized in the sport driving mode, the preset time period threshold value when the required torque is zero in the sport driving mode may be larger than the preset time period threshold value when the required torque is zero in the energy-saving driving mode. For example, in the energy-saving driving mode, the preset duration threshold may be 2S; in the sport driving mode, the preset duration threshold may be 5S. It is understood that the torque response capability of the vehicle in the sport driving mode is superior to the torque response capability in the standard driving mode and in the eco-drive mode; the cruising ability of the vehicle in the energy-saving driving mode is better than that in the standard driving mode and the motion driving mode; in the standard driving mode, the balance between the cruising ability and the torque response ability of the vehicle is emphasized.

According to the motor excitation control method for the automobile, different motor excitation control strategies can be executed according to different driving modes of the automobile, wherein when the driving mode is an energy-saving driving mode, the automobile can be guaranteed to have certain torque response capability, and meanwhile the cruising ability is maximized; when the driving mode is the standard driving mode, the vehicle can be ensured to have good cruising ability and torque response ability, and meanwhile the cruising ability and the torque response ability can reach a certain balance; when the driving mode is the motion driving mode, the vehicle can be ensured to have certain cruising ability, and meanwhile, the torque response capability is maximized.

As shown in fig. 8, fig. 8 shows a motor excitation control device 300 of an automobile according to an embodiment of the present application, and the motor excitation control device 300 of the automobile may include a torque obtaining module 310, a duration obtaining module 320, a first control module 330, and a second control module 340. The torque acquiring module 310 is used for acquiring the required torque of the motor; the duration acquisition module 320 is used for acquiring the duration of the zero torque of the required torque when the required torque is zero torque; the first control module 330 is configured to, if the duration reaches the preset duration threshold, reduce the excitation current of the motor from a normal current value to a preset current value when the duration reaches the preset duration threshold; the second control module 340 is configured to maintain the normal current value of the excitation current unchanged if the duration does not reach the preset duration threshold.

In some embodiments, the first control module 330 includes a first current control unit 331, a second current control unit 332, a third current control unit 333, and a fourth current control unit 334. The first current control unit 331 is configured to reduce an excitation current of the motor from a normal current value to a first preset current value; the second current control unit 332 is configured to reduce the excitation current of the motor from the normal current value to a second preset current value; the third current control unit 333 is configured to reduce the excitation current of the motor from the second preset current value to a third preset current value; the fourth current control unit 334 is configured to reduce the excitation current of the motor from the normal current value to a fourth preset current value.

In some embodiments, the second control module 340 includes a current maintaining unit 341 and a current adjusting unit 342. The current maintaining unit 341 is configured to maintain a normal current value of the excitation current unchanged; the current adjusting unit 342 is used for adjusting the exciting current from a second preset current value to a normal current value.

In some embodiments, the motor excitation control device 300 of the automobile further includes a mode determination module 350, a preset current determination module 360, a first determination module 370, a second determination module 380, and a third determination module 390. Wherein the mode determination module 350 is configured to determine a current driving mode of the vehicle; the preset current determining module 360 is configured to determine a preset current value according to the current driving mode; the first determining module 370 is configured to determine whether the duration reaches a preset duration threshold; the second determining module 380 is configured to determine whether the first duration reaches a first preset duration threshold; the third determining module 390 is configured to determine whether the second duration reaches a second preset duration threshold.

In some embodiments, the mode determination module 350 includes a signal acquisition unit 351, a first determination unit 352, a data acquisition unit 353, and a second determination unit 354. The signal acquiring unit 351 is used for acquiring a driving mode signal of the vehicle; the first determining unit 352 is configured to determine a current driving mode of the vehicle according to the driving mode signal; the data obtaining unit 353 is configured to obtain current driving data of the vehicle; the second determination unit 354 is configured to determine a current driving mode of the vehicle based on the current traveling data.

According to the motor excitation control device of the automobile, the device acquires the required torque of the motor; when the required torque is zero torque, acquiring the duration of the zero torque of the required torque; if the duration reaches the preset duration threshold, reducing the exciting current of the motor from the normal current value to the preset current value when the duration reaches the preset duration threshold; if the duration does not reach the preset duration threshold, the normal current value of the exciting current is maintained unchanged, and then the loss of the exciting current can be reduced when the required torque is zero, so that the energy is saved, the cruising ability of the electric automobile is improved, and meanwhile, the exciting current is prevented from being frequently cancelled and reestablished when the required torque is not zero, and the timeliness of torque response is ensured.

As shown in fig. 9, the embodiment of the present application further provides a vehicle 400, where the vehicle 400 includes a processor 410 and a memory 420, and the memory 420 stores computer program instructions, and the computer program instructions are invoked by the processor 410 to execute the motor excitation control method of the automobile.

Processor 410 may include one or more processing cores. The processor 410 interfaces with various components throughout the battery management system using various interfaces and lines to perform various functions of the battery management system and to process data by executing or executing instructions, programs, code sets, or instruction sets stored in the memory 420 and invoking data stored in the memory 420. Alternatively, the processor 410 may be implemented in hardware using at least one of Digital Signal Processing (DSP), Field-Programmable Gate Array (FPGA), and Programmable Logic Array (PLA). The processor 410 may integrate one or a combination of a Central Processing Unit (CPU) 410, a Graphics Processing Unit (GPU) 410, a modem, and the like. The CPU mainly processes an operating system, a user interface, an application program and the like; the GPU is used for rendering and drawing display content; the modem is used to handle wireless communications. It is understood that the modem may not be integrated into the processor 410, but may be implemented by a communication chip.

The Memory 420 may include a Random Access Memory (RAM) 420, and may also include a Read-Only Memory (Read-Only Memory) 420. The memory 420 may be used to store instructions, programs, code, sets of codes, or sets of instructions. The memory 420 may include a stored program area and a stored data area, wherein the stored program area may store instructions for implementing an operating system, instructions for implementing at least one function (such as a touch function, a sound playing function, an image playing function, etc.), instructions for implementing various method embodiments described below, and the like. The storage data area can also store data (such as a phone book, audio and video data, chat record data) created by the electronic device map in use and the like.

As shown in fig. 10, an embodiment of the present application further provides a computer-readable storage medium 500, where computer program instructions 510 are stored in the computer-readable storage medium 500, and the computer program instructions 510 can be called by a processor to execute the method described in the above embodiment.

The computer-readable storage medium may be an electronic memory such as a flash memory, an EEPROM (electrically erasable programmable read only memory), an EPROM, a hard disk, or a ROM. Alternatively, the computer-readable storage medium includes a non-volatile computer-readable storage medium. The computer-readable storage medium 600 has storage space for program code for performing any of the method steps described above. The program code can be read from or written to one or more computer program products. The program code may be compressed, for example, in a suitable form.

Although the present application has been described with reference to the preferred embodiments, it is to be understood that the present application is not limited to the disclosed embodiments, but rather, the present application is intended to cover various modifications, equivalents and alternatives falling within the spirit and scope of the present application.

Claims

1. A motor excitation control method of an automobile is characterized by comprising the following steps:

acquiring the required torque of the motor;

when the required torque is zero torque, acquiring the duration of the zero torque of the required torque;

if the duration reaches a preset duration threshold, reducing the exciting current of the motor from a normal current value to a preset current value when the duration reaches the preset duration threshold;

and if the duration does not reach the preset duration threshold, maintaining the normal current value of the exciting current unchanged.

2. The motor excitation control method of an automobile according to claim 1, wherein before said obtaining the required torque of the motor, said method further comprises:

determining a current driving mode of the vehicle; and

and determining the preset current value according to the current driving mode.

3. The motor excitation control method of an automobile according to claim 2, wherein when the current driving mode is a first driving mode, the preset current value is determined to be a first preset current value.

4. The motor excitation control method of an automobile according to claim 2, wherein when the current driving mode is a second driving mode, it is determined that the preset current value includes a second preset current value and a third preset current value, the second preset current value being greater than the third preset current value; the duration comprises a first duration and a second duration continuing with the first duration;

if the duration reaches a preset duration threshold, reducing the exciting current of the motor from a normal current value to a preset current value when the duration reaches the preset duration threshold, including:

if the first duration reaches a first preset duration threshold, reducing the exciting current of the motor from a normal current value to a second preset current value when the first duration reaches the first preset duration threshold; and

if the second duration reaches a second preset duration threshold, reducing the exciting current of the motor from the second preset current value to a third preset current value when the second duration reaches the second preset duration threshold.

5. The motor excitation control method of an automobile according to claim 3, wherein when the current driving mode is a third driving mode, it is determined that the preset current value is a fourth preset current value, and the fourth preset current value is greater than the first preset current value.

6. The motor excitation control method of an automobile according to any one of claims 2 to 5, wherein the determining of the current driving mode of the vehicle includes:

acquiring a driving mode signal of the vehicle; and

determining the current driving mode of the vehicle from the driving mode signal.

7. The motor excitation control method of an automobile according to any one of claims 2 to 5, wherein the determining of the current driving mode of the vehicle includes:

acquiring current driving data of the vehicle, wherein the current driving data comprises at least one of the following data: the average power of the motor in unit time, the average output torque of the motor in unit time and the accelerator depth; and

determining the current driving mode of the vehicle according to the current driving data.

8. An excitation control apparatus for an electric motor, the apparatus comprising:

the torque acquisition module is used for acquiring the required torque of the motor;

the duration acquisition module is used for acquiring the duration of zero torque of the required torque when the required torque is zero torque;

the first control module is used for reducing the exciting current of the motor from a normal current value to a preset current value when the duration reaches a preset duration threshold value if the duration reaches the preset duration threshold value; and

and the second control module is used for maintaining the normal current value of the exciting current unchanged if the duration does not reach the preset duration threshold.

9. A vehicle comprising a processor and a memory, the memory storing computer program instructions which, when invoked by the processor, perform a motor excitation control method for an automobile according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that the computer-readable storage medium stores a program code, wherein the program code when executed by a processor performs the method of any of claims 1-7.