Motor rotation speed measurement method, device, vehicle, medium and program product

Abstract

The present disclosure provides a motor rotating speed measurement method and device, vehicle, medium and program product, and relates to the technical field of vehicles, and comprises the following steps: determining a multi-phase current in a winding of a motor, and analyzing the multi-phase current to determine a current period and / or a current frequency of the multi-phase current; and obtaining the rotating speed of the motor according to the current period or the current frequency, without the need to additionally set a speed measurement device, thereby reducing the measurement cost, or in the case of a speed measurement device failure, the rotating speed of the motor can also be measured, and the reliability of the rotating speed measurement is improved.

Description

Technical Field

[0001] This disclosure relates to the field of vehicle technology, and in particular to a method, apparatus, vehicle, medium, and program product for measuring motor speed. Background Technology

[0002] During vehicle operation, a speed measuring device installed inside the motor is typically used to measure the motor's rotational speed. If the speed measuring device malfunctions, the motor's rotational speed cannot be recorded, potentially posing a driving risk. Summary of the Invention

[0003] To overcome the problems existing in related technologies, this disclosure provides a method, device, vehicle, medium, and program product for measuring motor speed.

[0004] According to a first aspect of the present disclosure, a method for measuring motor speed is provided. The method includes: determining a multiphase current in the windings of a motor, and determining the current period and / or current frequency of the multiphase current; determining the motor speed based on the current period or the frequency. This eliminates the need for an additional speed measuring device, reducing measurement costs, and allows for speed measurement even in the event of a speed measuring device failure, thus improving the reliability of speed measurement.

[0005] In some possible implementations, determining the current period of the multiphase current includes: determining the starting current and the ending current of the multiphase current, wherein the starting current and the ending current belong to the same phase current or different phase currents; determining a first number of current periods between the starting current and the ending current, and determining the duration between the starting current and the ending current; and determining the current period based on the first number of periods and the duration. This facilitates the subsequent determination of the motor speed, thus eliminating the need for an additional speed measuring device and reducing measurement costs.

[0006] In some possible implementations, determining the current frequency of the multiphase current includes: determining the current frequency of the multiphase current based on the current period.

[0007] In some possible implementations, determining the duration between the starting current and the ending current includes: determining a periodic signal for controlling the motor, and determining a second number of cycles of the periodic signal between the time corresponding to the starting current and the time corresponding to the ending current; determining the duration based on the signal period of the periodic signal and the second number of cycles. This can be used to subsequently determine the current period and / or current frequency, facilitating the subsequent determination of the motor speed, thus eliminating the need for an additional speed measuring device and reducing measurement costs.

[0008] In some possible implementations, there are multiple terminal currents. Determining the current period based on the first number of cycles and the duration includes: obtaining the first number of cycles corresponding to each terminal current among the multiple terminal currents, and the duration corresponding to each terminal current; determining the intermediate cycle corresponding to each terminal current to obtain multiple intermediate cycles; and obtaining the current period based on the average of the multiple intermediate cycles. This improves the accuracy of the current period, thereby improving the accuracy of the subsequent motor speed.

[0009] In some possible implementations, the number of first cycles corresponding to one of the plurality of terminal currents is determined by: determining the current cycle or current frequency corresponding to the terminal current preceding the current; determining the number of first cycles corresponding to the current current based on the current cycle or current frequency corresponding to the preceding terminal current, wherein the number of first cycles corresponding to the current current is inversely correlated with the current cycle corresponding to the preceding terminal current, and is positively correlated with the current frequency corresponding to the preceding terminal current. This approach balances the measurement efficiency and accuracy of the motor's speed.

[0010] In some possible implementations, the motor speed measurement method further includes: determining the number N of intermediate currents based on the number of the first cycles, wherein the magnitude of the intermediate currents is equal to the terminal currents, and N is 0 or a positive integer; determining the terminal current of the multiphase currents includes: determining the terminal currents by spacing N intermediate currents from the starting current.

[0011] In some possible implementations, the intermediate current is counted by: determining a preset current range in which the intermediate current lies; determining a threshold for the preset current range based on the trend corresponding to the intermediate current; and counting the intermediate current after detecting that the multiphase current exceeds the threshold. Thus, by introducing a preset current range in which the intermediate current lies, and counting the intermediate current after it exceeds the threshold, current interference such as current harmonics and sampling errors can be avoided, improving the accuracy of the intermediate current counting.

[0012] In some possible implementations, determining the motor speed based on the current cycle or the frequency includes: determining the motor speed based on the current cycle or the frequency when the motor is in active short-circuit mode; the motor speed measurement method further includes: controlling the motor to exit the active short-circuit mode when the speed is lower than a preset speed. This allows for timely exit from the active short-circuit mode, improving driving safety.

[0013] According to a second aspect of the present disclosure, a motor speed measuring device is provided, the motor speed measuring device comprising: a first determining module configured to determine a multiphase current in the windings of a motor, and to determine the current period and / or current frequency of the multiphase current; and a second determining module configured to determine the speed of the motor based on the current period or the frequency.

[0014] In some possible implementations, the first determining module includes: a period determining module configured to determine the starting current and the ending current of the multiphase current, wherein the starting current and the ending current belong to the same phase current or different phase currents; determine a first number of current cycles between the starting current and the ending current, and determine the duration between the starting current and the ending current; and determine the current cycle based on the first number of cycles and the duration.

[0015] In some possible implementations, the first determining module further includes a frequency determining module configured to determine the current frequency of the multiphase current based on the current period.

[0016] According to a third aspect of the present disclosure, a vehicle is provided, comprising: a processor; and a memory for storing processor-executable instructions; wherein the processor is configured to implement the steps of the method described in the first aspect when executing the instructions.

[0017] According to a fourth aspect of the present disclosure, a computer-readable storage medium is provided, having stored thereon computer program instructions that, when executed by a processor, implement the steps of the motor speed measurement method provided in the first aspect of the present disclosure.

[0018] According to a fifth aspect of the present disclosure, a computer program product is provided, including a computer program that, when executed by a processor, implements the steps of the method described in the first aspect.

[0019] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure. Attached Figure Description

[0020] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure.

[0021] Figure 1 This is a flowchart illustrating a method for measuring motor speed according to an exemplary embodiment.

[0022] Figure 2 This is a flowchart illustrating a method for measuring motor speed according to another exemplary embodiment.

[0023] Figure 3 The diagram shown is a three-phase current waveform.

[0024] Figure 4 The diagram shows the waveforms of the three-phase current and PWM pulse signal.

[0025] Figure 5 The diagram shown is a waveform of the A-phase current in a three-phase system.

[0026] Figure 6 This is a block diagram illustrating a motor speed measuring device according to an exemplary embodiment.

[0027] Figure 7 This is a block diagram illustrating a vehicle according to an exemplary embodiment. Detailed Implementation

[0028] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this disclosure. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this disclosure as detailed in the appended claims.

[0029] It should be noted that all actions involving the acquisition of signals, information, or data in this disclosure are carried out in compliance with the relevant data protection laws and policies of the country where the location is situated, and with authorization from the owner of the relevant device.

[0030] Furthermore, the intelligent driving described in this disclosure can also be called autonomous driving or assisted driving. All intelligent driving-related technologies in this disclosure are designed in accordance with the relevant laws and regulations of the country where the vehicle is located. For example, intelligent driving requires the driver's hands not to be taken off the steering wheel.

[0031] Specifically, with the development of sensing technology and the improvement of chip capabilities, intelligent driving provides people with more and more rich driving functions, gradually realizing different levels of driving experience. The Society of Automotive Engineers (SAE) provides a driving automation classification standard, including driving levels L0 to L5, where L0 is no automation, and the human driver has full control of the car. During driving, the driver can receive warnings or assistance from the driving system, such as automatic emergency braking (AEB), blind spot monitoring (BSM), or lane departure warning (LDW). Level 1 is driver assistance, where driving operations are jointly performed by the human driver and the driving system. The driving system provides driving support based on the driving environment, such as steering wheel inputs or acceleration / deceleration. Other driving operations are performed by the human driver, such as adaptive cruise control (ACC) or lane keep assistance / support (LKA / LKS). Level 2 is partial automation, providing driving support based on the driving environment, including steering wheel inputs and acceleration / deceleration. Other driving actions are performed by the human driver, such as a combination of adaptive cruise control (ACC) and lane keep assist. Level 0 to Level 2 are driving systems that primarily support the driver, who still needs to monitor the driving process and perform actions such as steering, braking, or acceleration as needed for safety. Levels 0 to 2 primarily provide support to the driver, who still needs to supervise the driving process and perform actions such as steering, braking, or acceleration as needed. Levels 3 to 5 can replace the driver in performing all driving operations. At Level 3, the driver must be prepared to take over driving. Levels 4 and 5 allow for partial and full driving under certain conditions, with the driver having the option to take over. Level 4 is highly automated, where the driving system can perform all driving operations, and the driver may not need to respond to requests from the system, for example, under suitable road and environmental conditions (such as closed parks, highways, city roads, or fixed routes). Level 5 is fully automated, where the driving system can autonomously perform all driving operations under various road and environmental conditions that a human driver can handle.

[0032] Vehicles can roam based on high-precision maps, including changing lanes, changing driving direction, passing intersections, and changing some navigation strategies during navigation driving based on high-precision maps. It can also include autonomous driving processes performed by vehicles based on high-precision map information and their understanding of the surrounding road structure when no specific destination is set.

[0033] It should be understood that there is some semantic overlap among the aforementioned concepts (passing an intersection, changing lanes, changing local navigation strategies, and changing driving direction). For example, there is some semantic overlap between "changing lanes" and "changing driving direction" because in some situations, such as when a vehicle changes from a straight lane to a right-turn lane, not only does the driving lane change, but the driving direction also changes. This application lists these concepts for the purpose of clarity and completeness.

[0034] During vehicle operation, the motor speed is typically measured using speed measuring devices (resolver transformers, Hall effect sensors, position sampling circuits, etc.) installed within the motor. If these devices malfunction, the motor speed cannot be recorded, potentially posing a driving risk. For example, when the motor is in three-phase active short-circuit mode (ASC), if the actual motor speed cannot be obtained, the vehicle controller cannot determine in real time whether the motor meets the conditions for exiting ASC. This could lead to a risk of system malfunction, such as delaying the exit from short-circuit mode during emergency braking, potentially causing secondary faults like overcurrent or overvoltage.

[0035] To address the aforementioned problems, this disclosure provides a method for measuring motor speed. Please refer to [link / reference]. Figure 1 The motor speed measurement method can be applied to Figure 6 The motor speed measuring device 200 shown Figure 7 The vehicle 600, computer program product, and computer-readable storage medium shown are illustrated below. The following example uses an application to a vehicle. The following will focus on... Figure 1 The process shown will be described in detail. The motor speed measurement method may include the following steps: Step S110: Determine the multiphase current in the windings of the motor, and determine the current period and / or current frequency of the multiphase current.

[0036] Optionally, the motor can be a three-phase motor, a six-phase motor, a nine-phase motor, etc. Correspondingly, the multiphase current can be a three-phase current, a six-phase current, a nine-phase current, etc. Based on the waveform of the multiphase current, the current period Te and / or the current frequency fe = 1 / Te are analyzed. The current period Te refers to the time required for a complete sine wave.

[0037] Step S120: Determine the speed of the motor based on the current period or the current frequency.

[0038] The motor speed is determined based on the relationship between the current period and the motor speed. The relationship between the current period Te and the motor speed n is as follows:

[0039] Where P is the pole log number.

[0040] The rotational speed is determined based on the relationship between current frequency and rotational speed. The relationship between current frequency *fe* and motor rotational speed *n* is as follows:

[0041] In this embodiment, the multiphase current in the motor winding is determined and analyzed to determine the current period and / or current frequency of the multiphase current. Based on the current period or current frequency, the motor speed is obtained. No additional speed measuring device is required, which reduces the measurement cost. Alternatively, the motor speed can be measured even if the speed measuring device fails, thus improving the reliability of speed measurement.

[0042] In one implementation, please refer to Figure 2 Step S110 includes: Step S111: Determine the starting current and ending current of the multiphase current, wherein the starting current and the ending current belong to the same phase current or different phase currents.

[0043] Multiphase currents are periodic. The starting current can be any current in the multiphase current system, and the ending current can be any current after the starting current. The starting current and the ending current can belong to the same phase current. For example, taking a three-phase multiphase current as an example, both the starting current and the ending current can belong to phase A. The starting current and the ending current can also belong to different phase currents. For example, the starting current belongs to phase A, and the ending current belongs to phase B or phase C.

[0044] For example, the starting current and the ending current can be zero-crossing points in the current, i.e., the current value is 0. For ease of understanding, this embodiment uses three-phase current as an example of multi-phase current; please refer to [link to relevant documentation]. Figure 3The three-phase currents are phase A current ia, phase B current ib, and phase C current ic. Within one cycle, there are six zero-crossing points: 0, 1 / 6, 2 / 6, 3 / 6, 4 / 6, and 5 / 6 of a current cycle. For example, the zero-crossing point corresponding to 1 / 6 of a current cycle Te represents the interval between phase A current and phase C current of 1 / 6 of a current cycle Te. It's easy to understand that if the starting current is phase A current and the ending current is phase C current, then the current cycle Te can be calculated at least at the second zero-crossing point of 1 / 6 of a current cycle Te. Therefore, the starting and ending currents can belong to different phases, allowing for a rapid determination of the current cycle Te. The zero-crossing point corresponding to 3 / 6 of a current cycle Te represents the interval between two zero-crossing points on phase A current of 1 / 6 of a current cycle Te.

[0045] Step S112: Determine the first number of current cycles between the starting current and the ending current, and determine the duration between the starting current and the ending current.

[0046] Determine the number of the first cycle K of the current cycle Te between the starting current and the ending current.

[0047] One method is to determine the duration by measuring the time between the starting current and the ending current using a timer inside the vehicle's controller.

[0048] As another approach, the motor speed changes under different operating conditions during vehicle operation. For example, the motor speed differs when the driver presses the accelerator or brake pedal. The motor speed also differs when the vehicle is climbing or descending a slope. The change in motor speed causes a corresponding change in the current cycle. The duration between the starting and ending currents can be timed using a fixed-period periodic signal. In this approach, the duration can also be determined by using a periodic signal internal to the controller to time the duration between the starting and ending currents. For example, the periodic signal can be a PWM (Pulse Width Modulation) pulse signal or a clock cycle signal. The periodic signal has a fixed period, which can be determined through register configuration.

[0049] The duration can be determined using either the M-method or the T-method. The M-method counts the number of periodic signals within a fixed time window (e.g., counting the number of PWM pulses). The T-method counts the duration required for a fixed pulse period.

[0050] For example, taking the M-method, a periodic signal for controlling the motor is determined, wherein the signal period of the periodic signal is fixed, for example, the signal period can be 100µs. The second number of periods N of the periodic signal between the time corresponding to the starting current and the time corresponding to the ending current is determined; based on the signal period Ts of the periodic signal and the second number of periods N, the duration Ts·N is determined. Figure 4 As shown, the periodic signal is a PWM pulse signal, and the duration of N PWM pulse signals is Ts·N=K·Te. Figure 4 In this case, K is 1.

[0051] The M-method is suitable for high-speed scenarios, while the T-method is suitable for low-speed scenarios. Motor speed is usually not fixed, and measurement of motor speed can continue throughout the entire driving process. In the initial measurement phase, the T-method can be used by default for the measurement duration to obtain the motor speed. If the motor speed is higher than a preset speed, switch to the M-method for the measurement duration. Conversely, if the speed is lower than the preset speed, switch back to the T-method. This adaptive switching between the M and T methods balances measurement accuracy and response speed.

[0052] Step S113: Determine the current cycle based on the first cycle number and the duration.

[0053] Multiplying the number of the first cycle by the number of current cycles equals the duration. Then, dividing the duration by the number of the first cycle gives the current cycle.

[0054] For example, the number of the first cycle K multiplied by the number of current cycles Te equals the duration Ts·N. Therefore, the current cycle Te is:

[0055] Therefore, the motor speed n is:

[0056] In another embodiment, step S110 includes: determining the current frequency fe of the multiphase current based on the current period Te, wherein the current frequency fe is as follows:

[0057] Optionally, the number of terminal currents is multiple, and determining the current period based on the number of first cycles and the duration includes: obtaining the number of first cycles corresponding to each terminal current among the multiple terminal currents, and the duration corresponding to each terminal current, determining the intermediate cycle corresponding to each terminal current, and obtaining multiple intermediate cycles; obtaining the current period based on the average value of the multiple intermediate cycles.

[0058] For example, the number of first cycles between the starting current and the ending current is determined, as well as the duration between the starting current and the ending current is determined, and the intermediate current of the ending current is determined based on the number of first cycles and the duration.

[0059] In this embodiment, the current cycle is obtained by averaging multiple intermediate currents, which improves the accuracy of the current cycle and thus improves the accuracy of the subsequent motor speed.

[0060] In one approach, K can be set based on experience; for example, K can be 0.5, 1, 2, 3, 4, 5, etc.

[0061] Alternatively, the number of first cycles corresponding to one of the plurality of terminal currents is determined by: determining the current period or current frequency corresponding to the terminal current preceding the current; and then determining the number of first cycles corresponding to the current current based on the current period or current frequency corresponding to the preceding terminal current.

[0062] For example, the previous terminal current could be the terminal current preceding this terminal current.

[0063] The number of first cycles corresponding to the terminal current is inversely correlated with the current cycle Te1 corresponding to the previous terminal current. For example, the number of first cycles corresponding to the terminal current is K2 = k / Te1, where k is a constant. Alternatively, the number of first cycles corresponding to the terminal current is positively correlated with the current frequency fe1 corresponding to the previous terminal current. For example, the number of first cycles corresponding to the terminal current is K2 = k·fe1, where k is a constant.

[0064] The motor speed changes gradually, and the speed corresponding to the previous terminal current is roughly the same as the speed corresponding to the current terminal current. Therefore, the frequency corresponding to the previous terminal current can roughly reflect the frequency corresponding to the current terminal current. In this embodiment, when the current cycle is high and the current frequency is low, the motor speed is low, and a lower number of first cycles K2 is used to quickly obtain the motor speed. Conversely, when the current cycle is low and the current frequency is high, the motor speed is high, and a higher number of first cycles K2 can be used to obtain a more accurate motor speed.

[0065] Optionally, determining the starting current of the multiphase current includes: determining any current in the multiphase current as the starting current.

[0066] For example, the starting current can be a zero-crossing point, that is, the starting current is 0.

[0067] The magnitude of the terminal current is equal to the magnitude of the starting current. For example, the terminal current can also be zero-crossing, i.e., the terminal current is 0.

[0068] Optionally, the motor speed measurement method further includes: determining the number N of intermediate currents based on the number of the first cycles, wherein the magnitude of the intermediate current is equal to the terminal current, and N is 0 or a positive integer.

[0069] For example, with Figure 3 Taking the three-phase current as an example, if the number of the first cycle is 0.5, then the number of zero-crossing points corresponding to this number of the first cycle is 4. Excluding the initial current and the final current, the number of intermediate currents is N, which is 2.

[0070] Based on this, determining the terminal current of the multiphase current includes: determining the terminal current by N intermediate currents spaced apart from the starting current.

[0071] For example, with Figure 3 Taking the three-phase current as an example, the initial current is ia. The origin of the coordinate system is the first zero-crossing point. After a gap of 2 intermediate currents (zero-crossing points), the next zero-crossing point is the terminal current.

[0072] Optionally, since current interference such as current harmonics and sampling errors may exist, causing current fluctuations, this embodiment introduces a preset current range (which can be understood as a hysteresis loop) to avoid counting errors caused by current fluctuations. The intermediate current is counted in the following way: the preset current range in which the intermediate current is located is determined; the threshold of the preset current range is determined according to the trend corresponding to the intermediate current; after detecting that the current of the multiphase current exceeds the threshold, which can be understood as the absolute value of the current being greater than the absolute value of the threshold, the intermediate current is counted.

[0073] For example, please see Figure 5 Taking the intermediate current 0 on phase A current ia as an example, the preset current range can be [-i0, i0]. The trend of the intermediate current is a downward trend, that is, it is at the falling edge of phase A current. The determined threshold is -i0. If the current exceeds -i0, the intermediate current is counted. Alternatively, the trend of the intermediate current is an upward trend, that is, it is at the rising edge of phase A current. The determined threshold is i0. If the current exceeds i0, the intermediate current is counted.

[0074] After the count reaches N, the next zero-crossing point is the terminal current.

[0075] In this embodiment, a preset current range is introduced for the intermediate current. After the intermediate current exceeds the threshold, the intermediate current is counted, which can avoid current interference such as current harmonics and sampling errors and improve the accuracy of intermediate current counting.

[0076] In one application scenario, step S120 includes: determining the speed of the motor based on the current cycle or the frequency when the motor is in active short-circuit (ASC) mode.

[0077] Therefore, the motor speed measurement method further includes: controlling the motor to exit the active short-circuit mode when the speed is lower than a preset speed. This ensures the motor exits the active short-circuit mode in a timely manner, improving driving safety.

[0078] In another application scenario, the measured motor speed using the motor speed measurement method of this disclosure can be used to determine whether the vehicle's speed measuring device is faulty. For example, the difference between the motor speed obtained by the speed measuring device and the speed determined in step S120 is calculated. If the difference is less than a preset difference, a detection result indicating that the speed measuring device is fault-free is obtained. If the difference is greater than the preset difference, a detection result indicating that the speed measuring device is faulty is obtained.

[0079] The motor speed measurement method disclosed herein balances speed estimation efficiency and accuracy by adjusting the adjustment time at different speeds. Specifically, it counts carrier pulses over multiple current cycles within the high-speed range, averages and filters the speed, and optimizes speed estimation accuracy without affecting the speed update frequency, facilitating more stable speed judgment under safe conditions. At low speeds, it reduces the time interval for faster speed updates; simultaneously, hysteresis processing is used for zero-crossing point detection to reduce speed estimation errors.

[0080] Based on the same inventive concept, this disclosure provides a motor speed measuring device. Please refer to [link to relevant documentation]. Figure 6 The motor speed measuring device 200 includes: The first determining module 210 is configured to determine the multiphase current in the winding of the motor, and to determine the current period and / or current frequency of the multiphase current. The second determining module 220 is configured to determine the speed of the motor based on the current cycle or the frequency.

[0081] In one possible implementation, the first determining module 210 includes: The period determination module is configured to: determine the starting current and the ending current of the multiphase current, wherein the starting current and the ending current belong to the same phase current or different phase currents; Determine the first number of current cycles between the starting current and the ending current, and determine the duration between the starting current and the ending current; determine the current cycle based on the first number of cycles and the duration.

[0082] In one possible implementation, the first determining module 210 further includes: The frequency determination module is configured to determine the current frequency of the multiphase current based on the current period.

[0083] In one possible implementation, the period determination module is specifically configured to: determine a periodic signal for controlling the motor, and determine the second number of periods of the periodic signal between the time corresponding to the starting current and the time corresponding to the ending current; The duration is determined based on the signal period of the periodic signal and the number of the second period.

[0084] In one possible implementation, the number of terminal currents is multiple, and the period determination module is specifically configured to: obtain the number of first periods corresponding to each terminal current among the multiple terminal currents, and the duration corresponding to each terminal current, determine the intermediate period corresponding to each terminal current, and obtain multiple intermediate periods. The current period is obtained based on the average value of the plurality of intermediate periods.

[0085] In one possible implementation, the period determination module is specifically configured to: determine the current period or current frequency corresponding to the end current preceding the end current; Based on the current period or current frequency corresponding to the previous terminal current, the number of the first period corresponding to the terminal current is determined, wherein the number of the first period corresponding to the terminal current is inversely correlated with the current period corresponding to the previous terminal current, and the number of the first period corresponding to the terminal current is positively correlated with the current frequency corresponding to the previous terminal current.

[0086] In one possible implementation, the motor speed measuring device 200 further includes: The third determining module is configured to determine the number N of intermediate currents based on the number of the first cycles, wherein the magnitude of the intermediate currents is equal to the end currents, and N is 0 or a positive integer; The period determination module is configured to determine the end current after N intermediate current intervals from the starting current.

[0087] In one possible implementation, the motor speed measuring device 200 further includes: The counting module is configured to: determine the preset current range in which the intermediate current is located; Based on the trend corresponding to the intermediate current, the threshold of the preset current range is determined; After detecting that the current of the multiphase current exceeds the threshold, the intermediate current is counted.

[0088] In one possible implementation, the first determining module is specifically configured to determine the speed of the motor based on the current cycle or the frequency when the motor is in active short-circuit mode; The motor speed measuring device 200 also includes: The exit module is configured to control the motor to exit the active short-circuit mode when the rotational speed is lower than the preset speed.

[0089] Regarding the motor speed measuring device 200 in the above embodiments, the specific manner in which each module performs its operation has been described in detail in the embodiments related to the method, and will not be elaborated here.

[0090] This disclosure also provides a computer-readable storage medium having stored thereon computer program instructions that, when executed by a processor, implement the steps of the motor speed measurement method provided in this disclosure.

[0091] Figure 7 This is a block diagram illustrating a vehicle 600 according to an exemplary embodiment. For example, vehicle 600 may be a hybrid vehicle, a non-hybrid vehicle, an electric vehicle, a fuel cell vehicle, or other types of vehicle. Vehicle 600 may have driver assistance functions.

[0092] Please refer to Figure 7 The vehicle 600 may include various subsystems, such as an infotainment system 610, a perception system 620, a decision control system 630, a drive system 640, and a computing platform 650. The vehicle 600 may also include more or fewer subsystems, and each subsystem may include multiple components. Furthermore, each subsystem and each component of the vehicle 600 can be interconnected via wired or wireless means.

[0093] In some embodiments, the infotainment system 610 may include a communication system, an entertainment system, and a navigation system, etc.

[0094] The perception system 620 may include several sensors for sensing information about the environment surrounding the vehicle 600. For example, the perception system 620 may include a global positioning system (which may be GPS, BeiDou, or other positioning systems), an inertial measurement unit (IMU), lidar, millimeter-wave radar, ultrasonic radar, and a camera device.

[0095] The decision control system 630 may include a computing system, a vehicle controller, a steering system, a throttle, and a braking system.

[0096] The drive system 640 may include components that provide powered motion to the vehicle 600. In one embodiment, the drive system 640 may include an engine, an energy source, a transmission system, and wheels. The engine may be one or a combination of internal combustion engines, electric motors, and compressed air engines. The engine is capable of converting energy provided by the energy source into mechanical energy.

[0097] Some or all of the functions of vehicle 600 are controlled by computing platform 650. Computing platform 650 may include at least one processor 651 and memory 652, processor 651 can execute instructions 653 stored in memory 652.

[0098] Processor 651 can be any conventional processor, such as a commercially available CPU. Processors may also include graphics processing units (GPUs), field-programmable gate arrays (FPGAs), systems-on-chips (SoCs), application-specific integrated circuits (ASICs), or combinations thereof.

[0099] The memory 652 can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic storage, flash memory, magnetic disk or optical disk.

[0100] In addition to instruction 653, memory 652 can also store data, such as road maps, route information, vehicle position, direction, speed, and other data. The data stored in memory 652 can be used by computing platform 650.

[0101] In this embodiment of the disclosure, processor 651 may execute instruction 653 to complete all or part of the steps of the above-described motor speed measurement method.

[0102] In another exemplary embodiment, a computer program product is also provided, which includes a computer program executable by a programmable device, the computer program having a code portion for performing the above-described motor speed measurement method when executed by the programmable device.

[0103] Those skilled in the art will also understand that the various illustrative logical blocks and steps listed in the embodiments of this application can be implemented by electronic hardware, computer software, or a combination of both. Whether such functionality is implemented through hardware or software depends on the specific application and the overall system design requirements. Those skilled in the art can implement the described functionality using various methods for each specific application, but such implementation should not be construed as exceeding the scope of protection of the embodiments of this application.

[0104] Furthermore, the term “exemplary” is used herein to mean serving as an example, instance, or illustration. Any aspect or design described herein as “exemplary” is not necessarily to be construed as advantageous compared to other aspects or designs. Rather, the use of the term “exemplary” is intended to present the concept in a concrete manner. As used herein, the term “or” is intended to mean an inclusive “or” rather than an exclusive “or.” That is, unless otherwise specified or clear from the context, “X applies A or B” is intended to mean any of the natural inclusive arrangements. That is, “X applies A or B” satisfies any of the foregoing instances if X applies A; X applies B; or both X applies A and B. Additionally, unless otherwise specified or clear from the context to refer to the singular form, the articles “a” and “an” as used in this application and the appended claims are generally understood to mean “one or more.”

[0105] Similarly, although this disclosure has been shown and described with respect to one or more implementations, equivalent variations and modifications will occur to those skilled in the art upon reading and understanding this specification and the accompanying drawings. This disclosure includes all such modifications and variations and is limited only by the scope of the claims. In particular, with respect to the various functions performed by the components described above (e.g., elements, resources, etc.), unless otherwise indicated, the terminology used to describe such components is intended to correspond to any component (functionally equivalent) that performs the specific function of the described component, even if structurally not equivalent to the disclosed structure. Furthermore, although specific features of this disclosure may have been disclosed with respect to only one of several implementations, such features may be combined with one or more other features of other implementations, as may be desired and advantageous to any given or particular application. Moreover, with regard to the terms “comprising,” “owning,” “having,” “having,” or variations thereof as used in the detailed description or claims, such terms are intended to be inclusive in a manner similar to the term “including.”

[0106] Other embodiments of this disclosure will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this disclosure are indicated by the appended claims.

[0107] It should be understood that this disclosure is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this disclosure is limited only by the appended claims.

Claims

1. A method for measuring motor speed, characterized in that, The motor speed measurement method includes: Determine the multiphase current in the windings of the motor, and determine the current period and / or current frequency of the multiphase current; The speed of the motor is determined based on the current period or the current frequency.

2. The motor speed measurement method according to claim 1, characterized in that, Determining the current period of the multiphase current includes: Determine the starting current and the ending current of the multiphase current, wherein the starting current and the ending current belong to the same phase current or different phase currents; Determine the first number of current cycles between the starting current and the ending current, and determine the duration between the starting current and the ending current; The current cycle is determined based on the number of the first cycles and the duration.

3. The motor speed measurement method according to claim 2, characterized in that, Determining the current frequency of the multiphase current includes: The current frequency of the multiphase current is determined based on the current period.

4. The motor speed measurement method according to claim 2, characterized in that, Determining the duration between the starting current and the ending current includes: Determine a periodic signal for controlling the motor, and determine the number of second cycles of the periodic signal between the time corresponding to the starting current and the time corresponding to the ending current; The duration is determined based on the signal period of the periodic signal and the number of the second period.

5. The method for measuring motor speed according to claim 2, characterized in that, The number of terminal currents is multiple, and determining the current cycle based on the first number of cycles and the duration includes: The number of first cycles corresponding to each terminal current in the multiple terminal currents and the duration corresponding to each terminal current are obtained, and the intermediate cycle corresponding to each terminal current is determined to obtain multiple intermediate cycles. The current period is obtained based on the average value of the plurality of intermediate periods.

6. The method for measuring motor speed according to claim 5, characterized in that, The number of first cycles corresponding to one of the plurality of terminal currents is determined in the following manner: Determine the current period or current frequency corresponding to the current preceding the current at the end; Based on the current period or current frequency corresponding to the previous terminal current, the number of the first period corresponding to the terminal current is determined, wherein the number of the first period corresponding to the terminal current is inversely correlated with the current period corresponding to the previous terminal current, and the number of the first period corresponding to the terminal current is positively correlated with the current frequency corresponding to the previous terminal current.

7. The method for measuring motor speed according to claim 2, characterized in that, The motor speed measurement method also includes: Based on the number of the first cycle, the number N of intermediate currents is determined, wherein the magnitude of the intermediate currents is equal to the terminal currents, and N is 0 or a positive integer; Determining the terminal current of the multiphase current includes: The final current is determined after N intermediate currents are spaced from the initial current.

8. The method for measuring motor speed according to claim 7, characterized in that, The intermediate current is counted in the following manner: Determine the preset current range in which the intermediate current is located; Based on the trend corresponding to the intermediate current, the threshold of the preset current range is determined; After detecting that the current of the multiphase current exceeds the threshold, the intermediate current is counted.

9. The method for measuring motor speed according to any one of claims 1 to 8, characterized in that, Determining the motor speed based on the current period or the frequency includes: When the motor is in active short-circuit mode, the motor speed is determined according to the current cycle or the frequency; The motor speed measurement method also includes: If the rotational speed is lower than the preset speed, the motor is controlled to exit the active short-circuit mode.

10. A motor speed measuring device, characterized in that, The motor speed measuring device includes: The first determining module is configured to determine the multiphase current in the windings of the motor, and to determine the current period and / or current frequency of the multiphase current. The second determining module is configured to determine the speed of the motor based on the current cycle or the frequency.

11. The motor speed measuring device according to claim 10, characterized in that, The first determining module includes: The period determination module is configured to determine the starting current and the ending current of the multiphase current, wherein the starting current and the ending current belong to the same phase current or different phase currents; determine the first number of current cycles between the starting current and the ending current, and determine the duration between the starting current and the ending current; and determine the current cycle based on the first number of cycles and the duration.

12. The motor speed measuring device according to claim 11, characterized in that, The first determining module further includes: The frequency determination module is configured to determine the current frequency of the multiphase current based on the current period.

13. A vehicle, characterized in that, include: processor; Memory used to store processor-executable instructions; The processor is configured to implement the steps of the method according to any one of claims 1 to 9 when executing the instruction.

14. A computer-readable storage medium having a computer program stored thereon, characterized in that, When executed by a processor, the computer program implements the steps of the method described in any one of claims 1 to 9.

15. A computer program product, characterized in that, It includes a computer program that, when executed by a processor, implements the steps of the method according to any one of claims 1 to 9.

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