Method, device and equipment for measuring back electromotive force and motor zero position and storage medium

Abstract

The invention discloses a counter electromotive force and motor zero position measuring method, device and equipment and a storage medium, and the method comprises the steps: controlling one of a first motor and a second motor to enter a power generation mode in a no-load manner according to the turning direction of a vehicle when the vehicle turns, and enabling the other motor to drag the first motor and the second motor to generate power; acquiring a test rotating speed of the first motor / the second motor in a dragged state; and determining the back electromotive force of the first motor / the second motor according to the test rotating speed, and determining the zero position of the motor when the back electromotive force crosses the zero position. When the vehicle is in a turning state in the running process, one motor is used for driving, and meanwhile, the other no-load motor is driven to generate power, so that the test rotating speed of the motor can be obtained by using related parameters, and the counter electromotive force of the motor is further derived according to the test rotating speed; and the zero position of the motor is detected when the counter electromotive force crosses the zero position, and finally the counter electromotive force and the zero position of the motor are detected in the running process of the vehicle.

Description

Technical Field

[0001] The present application relates to the technical field of automotive motor detection, and particularly relates to a method, device, equipment and storage medium for measuring back electromotive force and motor zero position. Background Art

[0002] With the increasing global emphasis on environmental protection, electric vehicles, as a clean and efficient means of transportation, are experiencing rapid growth in market demand and development speed. Among them, the motor drive system is the core part of electric vehicles, which directly affects the performance and efficiency of electric vehicles. The motor performance parameter control technology is the key technology of the motor drive system, which determines the operating state and performance of the motor. Among them, the back electromotive force and the motor zero position are the main parameters of the motor performance and are parameters that must be tested for each motor off the production line. The back electromotive force will change with the use time of the motor. Detecting and controlling the back electromotive force and the motor zero position of the motor can better and more accurately detect the running state of the vehicle and can more accurately control the output performance of the vehicle.

[0003] Most of the existing electric drives are single motors or dual motors, one for driving and one for generating electricity. The back electromotive force test is generally carried out offline. The test method is to prepare a power supply and a companion motor, and use the power supply, test instruments, etc. to perform a counter-dragging test. However, the current test method requires users to drive the vehicle to the offline detection location for detection, which takes up a certain amount of time for users. For the vehicles of users who have not been to the offline detection location for a long time, there are certain control hidden dangers in the motors of their vehicles. Therefore, there is room for further improvement in the test method for the back electromotive force and zero position of vehicle motors. Summary of the Invention

[0004] The present application provides a method, device, equipment and storage medium for measuring back electromotive force and motor zero position, which can solve the technical problems existing in the above-mentioned prior art.

[0005] In a first aspect, an embodiment of the present application provides a method for measuring back electromotive force and motor zero position, adopting the following technical solution:

[0006] A method for measuring back electromotive force and motor zero position, based on a vehicle having a first motor and a second motor, and the first motor and the second motor can drag each other. The method includes:

[0007] When the vehicle turns, control one of the first motor and the second motor to enter the power generation mode without load according to the turning direction of the vehicle, and have the other motor drag it for power generation;

[0008] Obtain the test speed of the first motor / second motor in the dragged state;

[0009] Determine the back electromotive force of the first motor / second motor according to the measured rotational speed, and determine the motor zero position when the back electromotive force crosses the zero position.

[0010] Combined with the first aspect, in an embodiment, the controlling one of the first motor and the second motor to enter the power generation mode without load according to the turning direction of the vehicle and driving the power generation by the other motor includes the following steps:

[0011] If the vehicle turns to the right, the second motor is without load, and the first motor participating in the right turn drive drives the second motor to rotate and generate electricity;

[0012] If the vehicle turns to the left, the first motor is without load, and the second motor participating in the left turn drive drives the first motor to rotate and generate electricity.

[0013] Combined with the first aspect, in an embodiment, before controlling one of the first motor and the second motor to enter the power generation mode without load according to the turning direction of the vehicle and driving the power generation by the other motor when the vehicle is turning, the following steps are included:

[0014] Obtain the vehicle operation parameters, and determine whether the vehicle operation parameters meet the preset test conditions;

[0015] If it meets the conditions, enter the test preparation state and execute the subsequent test method;

[0016] If it does not meet the conditions, continue to drive in the normal driving mode.

[0017] Combined with the first aspect, in an embodiment, the obtaining the vehicle operation parameters and determining whether the vehicle operation parameters meet the preset test conditions includes the following steps:

[0018] Determine whether the vehicle speed information and the slope information in the vehicle operation parameters meet the preset vehicle speed requirement and slope requirement respectively;

[0019] If both meet the conditions, confirm that the preset test conditions are met.

[0020] Combined with the first aspect, in an embodiment, the vehicle speed requirement is dynamically calculated from the reduction gear transmission ratio and the output shaft diameter.

[0021] Combined with the first aspect, in an embodiment, in the controlling one of the first motor and the second motor to enter the power generation mode without load according to the turning direction of the vehicle and driving the power generation by the other motor when the vehicle is turning,

[0022] According to the preset test time, control the no-load time of one of the first motor and the second motor and the driving rotation time of the other motor for it.

[0023] In combination with the first aspect, in one embodiment, before controlling one of the first motor and the second motor to enter the power generation mode with no load according to the turning direction of the vehicle and driving it to generate power by the other motor when the vehicle turns, the following steps are included:

[0024] Obtain the turning duration calculated based on the current vehicle speed and the next turning path;

[0025] Determine whether the turning duration is greater than the test time;

[0026] If it is greater, allow the subsequent test method to be executed when turning along the next turning path;

[0027] If it is not greater, do not allow the subsequent test method to be executed when turning along the next turning path.

[0028] In the second aspect, an embodiment of the present application provides a device for measuring back electromotive force and motor zero position, and the following technical solution is adopted:

[0029] A device for measuring back electromotive force and motor zero position, the device includes:

[0030] A test control module configured to control one of the first motor and the second motor to enter the power generation mode with no load according to the turning direction of the vehicle and drive it to generate power by the other motor when the vehicle turns;

[0031] A calculation module configured to determine the back electromotive force of the first motor / second motor according to the test speed and determine the motor zero position when the back electromotive force crosses the zero position.

[0032] In the third aspect, an embodiment of the present application provides a device for measuring back electromotive force and motor zero position, and the following technical solution is adopted:

[0033] A device for measuring back electromotive force and motor zero position, the device for measuring back electromotive force and motor zero position includes a processor, a memory, and a program for measuring back electromotive force and motor zero position stored on the memory and executable by the processor. When the program for measuring back electromotive force and motor zero position is executed by the processor, the steps of the method for measuring back electromotive force and motor zero position as described above are implemented.

[0034] In the fourth aspect, an embodiment of the present application provides a storage medium, and the following technical solution is adopted:

[0035] A storage medium, on which a program for measuring back electromotive force and motor zero position is stored. When the program for measuring back electromotive force and motor zero position is executed by a processor, the steps of the method for measuring back electromotive force and motor zero position as described above are implemented.

[0036] The beneficial effects brought by the technical solutions provided in the embodiments of the present application include:

[0037] When the vehicle is turning during driving, it is not necessary for both motors to participate in driving at the same time. At this time, one of the motors can be used as the driving motor while driving the other unloaded motor to generate electricity. During the power generation process of the unloaded motor, relevant parameters can be used to obtain the test speed of the motor, and the back electromotive force of the motor can be further derived based on the test speed. When the back electromotive force crosses the zero position, the zero position of the motor can be detected, and finally, the back electromotive force and zero position detection of the motor can be realized during the vehicle driving process. Description of the Drawings

[0038] Figure 1 It is a schematic flowchart of an embodiment of the method for measuring the back electromotive force and the zero position of the motor in the present application;

[0039] Figure 2 It is a schematic diagram of the functional modules of an embodiment of the device for measuring the back electromotive force and the zero position of the motor in the present application;

[0040] Figure 3 It is a schematic diagram of the hardware structure of the device for measuring the back electromotive force and the zero position of the motor involved in the solution of the embodiment of the present application. Detailed Embodiments

[0041] In order to enable those skilled in the art to better understand the solution of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the protection scope of the present application.

[0042] With the increasing global emphasis on environmental protection, electric vehicles (EVs), as a clean and efficient means of transportation, are experiencing rapid market growth and development. The motor drive system is a core component of EVs, directly impacting their performance and efficiency. Motor performance parameter control technology is a key technology in the motor drive system, determining the motor's operating status and performance. Back EMF and motor zero position are key motor performance parameters and must be tested before every motor is shipped. Back EMF changes with age, and monitoring and controlling these parameters allows for more accurate monitoring of vehicle operating status and precise control of output performance. Most existing EVs utilize a single or dual motor—one for driving and one for generating. Back EMF testing is typically performed offline, using a power supply, a test motor, and test equipment for a tow-and-pull test. However, the current testing method requires users to drive their vehicles to an offline testing location for testing, which takes up a certain amount of user time. For users' vehicles that have not been tested at an offline testing location for a long time, there are certain control risks in their vehicle motors. Therefore, there is room for further improvement in the testing methods for vehicle motor back electromotive force and zero position.

[0043] Based on the above problems, the present application provides a method, device, equipment and storage medium for measuring back electromotive force and motor zero position. The key point of the invention is that, by eliminating the need for two motors to drive at the same time when the vehicle is turning during driving, one of the motors can be used as the driver while driving the other unloaded motor to generate electricity. During the process of power generation by the unloaded motor, the relevant parameters can be used to obtain the test speed of the motor, and the back electromotive force of the motor can be further deduced based on the test speed. The zero position of the motor can be detected when the back electromotive force crosses the zero position, thereby finally realizing the back electromotive force and zero position detection of the motor during vehicle driving.

[0044] In order to make the objectives, technical solutions and advantages of this application clearer, the implementation methods of this application will be further described in detail below with reference to the accompanying drawings.

[0045] In a first aspect, an embodiment of the present application provides a method for measuring back electromotive force and motor zero position, based on a vehicle having a first motor and a second motor, wherein the first motor and the second motor can drag each other.

[0046] In one embodiment, referring to Figure 1 , Figure 1 This is a flow chart of the first embodiment of the method for measuring back electromotive force and motor zero position of this application. Figure 1 As shown in the figure, the measurement methods of back electromotive force and motor zero position include:

[0047] S100. When the vehicle is turning, according to the turning direction of the vehicle, control one of the first motor and the second motor to enter the power generation mode without load, and let the other motor drive it to generate electricity;

[0048] Specifically, when controlling one of the first motor and the second motor to enter the power generation mode without load according to the turning direction of the vehicle, and letting the other motor drive it to generate electricity, the following steps are included:

[0049] S100. If the vehicle turns to the right, the second motor is without load, and the first motor participating in the right-turn drive preset drives the second motor to rotate and generate electricity;

[0050] S110. If the vehicle turns to the left, the first motor is without load, and the second motor participating in the left-turn drive preset drives the first motor to rotate and generate electricity.

[0051] S200. Obtain the test speed of the first motor / second motor in the driven state;

[0052] Specifically, the test speed is obtained by relevant detection equipment installed on the vehicle and connected to the first motor / second motor, such as a speed sensor. After the detection equipment obtains the test speed in this application, the test speed data will be directly called.

[0053] S300. Determine the back electromotive force of the first motor / second motor according to the test speed, and when the back electromotive force crosses the zero position, determine the motor zero position.

[0054] Specifically, after obtaining the test speed, the back electromotive force corresponding to the speed will be further calculated by a variable-frequency power analyzer installed on the vehicle and transmitted to the relevant data processing unit. The data processing unit calculates the back electromotive force constant and transmits it to the whole machine control unit. At the same time, the encoder monitors the state of the back electromotive force and then identifies the zero position.

[0055] Finally, during the turning state of the vehicle during driving, it is not necessary for both motors to participate in driving at the same time. At this time, one of the motors can be used as the drive while driving the other motor without load to generate electricity. During the power generation process of the motor without load, relevant parameters can be used to obtain the test speed of the motor, and the back electromotive force of the motor can be further deduced according to the test speed, and when the back electromotive force crosses the zero position, the zero position of the motor can be detected, and finally the back electromotive force and zero position detection of the motor can be realized during the vehicle driving process.

[0056] Further, in order to implement the above test method in a suitable turning state, in one embodiment, before the step S100, when the vehicle is turning, controlling one of the first motor and the second motor to enter the power generation mode without load according to the turning direction of the vehicle, and dragging and generating power by the other motor, the following steps are included:

[0057] S010. Obtain the vehicle operation parameters, and determine whether the preset test conditions are met according to the vehicle operation parameters;

[0058] S011. If the conditions are met, enter the test preparation state and execute the subsequent test method;

[0059] S012. If the conditions are not met, continue to drive in the normal driving mode.

[0060] In this embodiment, before performing the test process when the vehicle is turning, by mastering the current vehicle operation parameters, it is known whether the current vehicle is suitable for stable and effective testing in the subsequent turning process. When it is determined to be appropriate, the vehicle enters the test preparation state and can execute the test process in the subsequent turning process. If the current driving state is determined to be inappropriate, it does not enter the test preparation state and continues to drive in the normal driving mode to ensure the driving safety of the vehicle.

[0061] Further, in one embodiment, S010, the step of obtaining the vehicle operation parameters and determining whether the preset test conditions are met according to the vehicle operation parameters includes the following steps:

[0062] S0101. Determine whether the vehicle speed information and the slope information in the vehicle operation parameters respectively meet the preset vehicle speed requirements and slope requirements;

[0063] S0102. If both meet the requirements, confirm that the preset test conditions are met.

[0064] In this embodiment, it is determined whether the current road surface is flat through the slope information. If the slope information is not within the preset slope range, for example, lower or higher, it means that the current vehicle is in an uphill or downhill state. Performing the subsequent test method in such a driving scenario with higher requirements for vehicle driving control is not conducive to driving safety. Therefore, it will be confirmed that the preset test conditions are not met. On the contrary, it is confirmed that the preset test conditions are met, and the vehicle can enter the test preparation state.

[0065] Meanwhile, since there are certain requirements for the rotational speed of the input shaft of the motor during the process of testing the back electromotive force of the motor, the rotational speed of the input shaft of the motor under test is associated with the rotational speed of the output shaft of another motor that drives it to rotate, and the rotational speed of the output shaft of the other motor that drives it to rotate will also be synchronously reflected in the vehicle speed. That is, only when the vehicle speed meets the corresponding requirements can the motor under test be tested more accurately. Therefore, it is also necessary to measure the back electromotive force of the motor under test when the vehicle speed meets the vehicle speed requirements.

[0066] Further, in some embodiments, in step S100, when the vehicle is turning, according to the turning direction of the vehicle, one of the first motor and the second motor is controlled to enter the power generation mode without load, and the other one drags it to generate electricity.

[0067] According to the preset test time, control the no-load time of one of the first motor and the second motor and the driving rotation time of the other one for it.

[0068] With this setting, only the operating state of one motor dragging another motor to generate electricity is executed within the test time. This test time is the shortest time for the test method to accurately test the back electromotive force of the motor. After this test time, the normal driving state of the vehicle can be restored.

[0069] Further, in some embodiments, since the vehicle speed requirement is dynamically calculated from the reduction gear transmission ratio and the output shaft diameter. And there may be differences in the reduction gear transmission ratios of current vehicles. Therefore, in this embodiment, the vehicle speed requirement is dynamically calculated from the reduction gear transmission ratio and the output shaft diameter. To effectively ensure that the vehicle speed requirement can match the rotational speed of the motor input shaft required for testing the motor.

[0070] Further, in some embodiments, since the above test method requires a certain test time, when the turning duration of the vehicle during turning is less than the required test time, it will affect the test process. Therefore, before step S100, when the vehicle is turning, according to the turning direction of the vehicle, one of the first motor and the second motor is controlled to enter the power generation mode without load, and the other one drags it to generate electricity, the following steps are included:

[0071] S013. Obtain the turning duration calculated based on the current vehicle speed and the next turning path;

[0072] Among them, the next turning path can be obtained by analyzing the vehicle navigation data.

[0073] S014. Judge whether the turning duration is greater than the test time;

[0074] S015. If it is greater, allow the subsequent test method to be executed when turning along the next turning path.

[0075] S016. If it is not greater than, it is not allowed to execute the subsequent test method on the next turning path.

[0076] By setting like this, when it is predicted that the time duration for passing through the next turning path is too short to execute the subsequent test method, it is not allowed to execute the subsequent test method on the next turning path, so as to avoid obtaining a result with a large deviation in measurement.

[0077] In a second aspect, an embodiment of the present application further provides a device for measuring back electromotive force and motor zero position.

[0078] In one embodiment, referring to Figure 2 , Figure 2 is a schematic diagram of the functional modules of an embodiment of the device for measuring back electromotive force and motor zero position of the present application. As Figure 2 shown, the device for measuring back electromotive force and motor zero position includes:

[0079] A test control module, which is configured to, when the vehicle turns, control one of the first motor and the second motor to enter the power generation mode without load according to the turning direction of the vehicle, and the other motor drags it to generate electricity;

[0080] A calculation module, which is configured to determine the back electromotive force of the first motor / second motor according to the test rotation speed, and determine the motor zero position when the back electromotive force crosses the zero position.

[0081] Further, in one embodiment, the test control module is further configured to, when executing the control of one of the first motor and the second motor to enter the power generation mode without load according to the turning direction of the vehicle and the other motor drags it to generate electricity, include the following steps:

[0082] If the vehicle turns to the right, the second motor is without load, and the first motor participating in the right turn drive preset drags the second motor to rotate and generate electricity;

[0083] If the vehicle turns to the left, the first motor is without load, and the second motor participating in the left turn drive preset drags the first motor to rotate and generate electricity.

[0084] Further, in one embodiment, the test control module is further configured to, before executing the control of one of the first motor and the second motor to enter the power generation mode without load according to the turning direction of the vehicle and the other motor drags it to generate electricity when the vehicle turns, include the following steps:

[0085] Obtain the vehicle operation parameters, and judge whether they meet the preset test conditions according to the vehicle operation parameters;

[0086] If it meets, enter the test preparation state and execute the subsequent test method;

[0087] If not, continue to drive in the normal driving mode.

[0088] Further, in one embodiment, the test control module is further configured to execute the obtaining of the vehicle operation parameters and determine whether the preset test conditions are met according to the vehicle operation parameters, including the following steps:

[0089] Determine whether the vehicle speed information and the slope information in the vehicle operation parameters respectively meet the preset vehicle speed requirements and slope requirements;

[0090] If both meet, confirm that the preset test conditions are met.

[0091] Further, in one embodiment, the test control module is further configured to execute the control of one of the first motor and the second motor to enter the power generation mode without load according to the turning direction of the vehicle and drag the other motor to generate power,

[0092] According to the preset test time, control the no-load time of one of the first motor and the second motor and the driving rotation time of the other motor for it.

[0093] Further, in one embodiment, the test control module is further configured to execute the steps before controlling one of the first motor and the second motor to enter the power generation mode without load according to the turning direction of the vehicle and dragging the other motor to generate power when the vehicle turns, including the following steps:

[0094] Obtain the turning duration calculated based on the current vehicle speed and the next turning path;

[0095] Determine whether the turning duration is greater than the test time;

[0096] If it is greater, allow the execution of the subsequent test method at the next turning path;

[0097] If it is not greater, do not allow the execution of the subsequent test method at the next turning path.

[0098] Wherein, the function implementation of each module in the above back electromotive force and motor zero position measuring device corresponds to each step in the above back electromotive force and motor zero position measuring method embodiment, and its function and implementation process will not be elaborated here one by one.

[0099] In a third aspect, an embodiment of the present application provides a back electromotive force and motor zero position measuring device. The back electromotive force and motor zero position measuring device can be a device with data processing functions such as a personal computer (PC), a laptop computer, a server, etc.

[0100] Refer to Figure 3 ,Figure 3 This is a schematic diagram of the hardware structure of the back electromotive force and motor zero position measurement device involved in the solution of the embodiment of the present application. In the embodiment of the present application, the back electromotive force and motor zero position measurement device may include a processor, a memory, a communication interface, and a communication bus.

[0101] Among them, the communication bus can be of any type and is used to interconnect the processor, the memory, and the communication interface.

[0102] The communication interface includes interfaces such as input / output (I / O) interfaces, physical interfaces, and logical interfaces for interconnecting components inside the back electromotive force and motor zero position measurement device, as well as interfaces for interconnecting the back electromotive force and motor zero position measurement device with other devices (such as other computing devices or user devices). The physical interface can be an Ethernet interface, an optical fiber interface, an ATM interface, etc.; the user device can be a display, a keyboard, etc.

[0103] The memory can be various types of storage media, such as random access memory (RAM), read-only memory (ROM), non-volatile RAM (NVRAM), flash memory, optical memory, hard disk, programmable ROM (PROM), erasable PROM (EPROM), electrically erasable PROM (EEPROM), etc.

[0104] The processor can be a general-purpose processor, and the general-purpose processor can call the back electromotive force and motor zero position measurement program stored in the memory and execute the back electromotive force and motor zero position measurement method provided by the embodiment of the present application. For example, the general-purpose processor can be a central processing unit (CPU). Among them, the method executed when the back electromotive force and motor zero position measurement program is called can refer to the various embodiments of the back electromotive force and motor zero position measurement method of the present application, which will not be elaborated here.

[0105] Those skilled in the art can understand that Figure 3 the hardware structure shown in does not constitute a limitation to the present application, and may include more or fewer components than shown in the figure, or combine some components, or have different component arrangements.

[0106] In a fourth aspect, the embodiment of the present application further provides a storage medium.

[0107] The storage medium of the present application stores a measurement program for back electromotive force and motor zero position. When the measurement program for back electromotive force and motor zero position is executed by a processor, the steps of the measurement method for back electromotive force and motor zero position as described above are implemented.

[0108] Among them, the method implemented when the measurement program for back electromotive force and motor zero position is executed can refer to each embodiment of the measurement method for back electromotive force and motor zero position of the present application, which will not be elaborated here.

[0109] It should be noted that the serial numbers of the embodiments of the present application above are only for description and do not represent the advantages or disadvantages of the embodiments.

[0110] The terms "including" and "having" and any variations thereof in the specification, claims and drawings of the present application are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally further includes steps or units not listed, or optionally further includes other steps or units inherent to these processes, methods, products or devices. The descriptions of "first", "second", "third", etc. are used to distinguish different objects, etc., and do not represent a sequence, nor do they limit that "first", "second" and "third" are different types.

[0111] In the description of the embodiments of the present application, "exemplary", "for example" or "for instance" are used to indicate examples, illustrations or explanations. Any embodiment or design solution described as "exemplary", "for example" or "for instance" in the embodiments of the present application should not be construed as being more preferred or having more advantages than other embodiments or design solutions. Rather, the use of words such as "exemplary", "for example" or "for instance" is intended to present relevant concepts in a specific manner.

[0112] In the description of the embodiments of the present application, unless otherwise specified, " / " means "or". For example, A / B may represent A or B; "and / or" in the text is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, in the description of the embodiments of the present application, "a plurality of" means two or more than two.

[0113] In some processes described in the embodiments of the present application, there are multiple operations or steps that appear in a specific order. However, it should be understood that these operations or steps may not be executed in the order in which they appear in the embodiments of the present application or may be executed in parallel. The serial numbers of the operations are only used to distinguish different operations, and the serial numbers themselves do not represent any execution order. In addition, these processes may include more or fewer operations, and these operations or steps may be executed in sequence or in parallel, and these operations or steps may be combined.

[0114] Through the description of the above embodiments, those skilled in the art can clearly understand that the above-described embodiment methods can be implemented by means of software plus a necessary general hardware platform. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present application, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. The computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) as described above and includes several instructions for causing a terminal device to execute the methods described in the various embodiments of the present application.

[0115] The above are only the preferred embodiments of the present application, and do not limit the patent scope of the present application. Any equivalent structural or equivalent process transformation made by using the content of the specification and drawings of the present application, or directly or indirectly applied in other related technical fields, shall be equally included in the patent protection scope of the present application.

Claims

1. A method for measuring back electromotive force and motor zero position, characterized in that, Based on a vehicle having a first motor and a second motor, and the first motor and the second motor can drive each other, the method includes: When the vehicle turns, control one of the first motor and the second motor to enter the power generation mode without load according to the turning direction of the vehicle, and drive it to generate power by the other motor; Obtain the test speed of the first motor / second motor in the driven state; Determine the back electromotive force of the first motor / second motor according to the test speed, and determine the motor zero position when the back electromotive force crosses the zero position.

2. The method for measuring back electromotive force and motor zero position according to claim 1, characterized in that, The controlling one of the first motor and the second motor to enter the power generation mode without load according to the turning direction of the vehicle, and driving it to generate power by the other motor includes the following steps: If the vehicle turns to the right, the second motor is without load, and the first motor participating in the right turn drive preset drags the second motor to rotate and generate power; If the vehicle turns to the left, the first motor is without load, and the second motor participating in the left turn drive preset drags the first motor to rotate and generate power.

3. The method for measuring back electromotive force and motor zero position according to claim 1, characterized in that Before controlling one of the first motor and the second motor to enter the power generation mode without load according to the turning direction of the vehicle when the vehicle turns, and driving it to generate power by the other motor, the following steps are included: Obtain the vehicle operation parameters, and judge whether they meet the preset test conditions according to the vehicle operation parameters; If they meet, enter the test preparation state and execute the subsequent test method; If they do not meet, continue to drive in the normal driving mode.

4. The method for measuring back electromotive force and motor zero position according to claim 3, characterized in that, The obtaining the vehicle operation parameters and judging whether they meet the preset test conditions according to the vehicle operation parameters includes the following steps: Judge whether the vehicle speed information and the slope information in the vehicle operation parameters meet the preset vehicle speed requirement and slope requirement respectively; If both meet, confirm that the preset test conditions are met.

5. The method for measuring back electromotive force and motor zero position according to claim 4, characterized in that, The vehicle speed requirement is dynamically calculated by the reduction gear transmission ratio and the output shaft diameter.

6. The method for measuring back electromotive force and motor zero position according to claim 1, wherein In the controlling one of the first motor and the second motor to enter the power generation mode without load according to the turning direction of the vehicle when the vehicle turns, and driving it to generate power by the other motor, According to the preset test time, control the no-load time of one of the first motor and the second motor and the driving rotation time of the other motor for it.

7. The method for measuring back electromotive force and motor zero position according to claim 6, characterized in that, Before controlling one of the first motor and the second motor to enter the power generation mode without load according to the turning direction of the vehicle when the vehicle turns, and driving it to generate power by the other motor, the following steps are included: Obtain the turning duration calculated based on the current vehicle speed and the next turning path; Judge whether the turning duration is greater than the test time; If it is greater, allow to execute the subsequent test method at the next turning path; If it is not greater, do not allow to execute the subsequent test method at the next turning path.

8. A device for measuring back electromotive force and motor zero position, characterized in that, The device includes: A test control module configured to control one of the first motor and the second motor to enter the power generation mode without load according to the turning direction of the vehicle when the vehicle turns, and drive it to generate power by the other motor; A calculation module configured to determine the back electromotive force of the first motor / second motor according to the test speed, and determine the motor zero position when the back electromotive force crosses the zero position.

9. A measuring device for back electromotive force and motor zero position, characterized in that, The measurement device for back electromotive force and motor zero position includes a processor, a memory, and a measurement program for back electromotive force and motor zero position stored on the memory and executable by the processor. When the measurement program for back electromotive force and motor zero position is executed by the processor, the steps of the measurement method for back electromotive force and motor zero position as described in any one of claims 1 to 7 are implemented.

10. A storage medium, characterized in that, A measurement program for back electromotive force and motor zero position is stored on the storage medium. When the measurement program for back electromotive force and motor zero position is executed by a processor, the steps of the measurement method for back electromotive force and motor zero position as described in any one of claims 1 to 7 are implemented.

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