Phase loss detection method and system of permanent magnet synchronous motor, medium and product

Abstract

The invention discloses a permanent magnet synchronous motor open-phase detection method and system, a medium and a product. The method comprises the following steps: acquiring a real-time three-phase current and a real-time load state of the steering motor; multiplying the absolute value of the real-time three-phase current by a preset coefficient to obtain a target three-phase current; respectively carrying out accumulation calculation on the target three-phase current to obtain a three-phase current accumulation sum; when the current cumulative sum exceeds a preset cumulative sum threshold value, or the steering angle of a steering wheel of a target vehicle corresponding to the steering motor changes, the three-phase current cumulative sum is reset to be a preset three-phase current cumulative sum; calculating an accumulated ratio set; obtaining a specific value threshold value corresponding to each accumulated specific value in the accumulated specific value set; determining whether there is an accumulated ratio exceeding a ratio threshold; if yes, adding one to the phase loss times; if not, zero setting is carried out on the phase loss times; and when the phase loss frequency exceeds a preset frequency threshold value, executing an early warning strategy. By implementing the above technical scheme, the accuracy of open-phase fault detection of the permanent magnet synchronous motor is improved.

Description

Technical Field

[0001] The present application relates to the field of motor technology, and in particular to a method, system, medium and product for detecting phase loss in a permanent magnet synchronous motor. Background Art

[0002] Permanent magnet synchronous motors (PMSMs) are widely used in the drive and steering systems of new energy vehicles due to their high efficiency, high power density, and excellent dynamic performance. However, under complex operating conditions, motor phase loss can cause torque fluctuations, reduced efficiency, and even system failure, seriously impacting driving safety. Therefore, accurate and rapid detection of phase loss faults is crucial to ensuring reliable motor operation, especially in the steering systems of new energy vehicles, where misidentification of faults can directly threaten driving safety.

[0003] Currently, determining whether a motor has a phase loss fault is typically done by monitoring the motor's three-phase current in real time. One common method involves setting a current threshold. When the current of a particular phase remains below the threshold for a continuous period of time, a phase loss fault is detected. Another method involves calculating the average absolute value of the three-phase current over a period of time and measuring the ratio of the maximum to minimum values. If this ratio exceeds a preset threshold, a phase loss fault is detected.

[0004] However, due to the rapid changes in load and speed of the steering motor when the vehicle is turning, the amplitude and phase relationship of the three-phase current are not fixed, but exhibit dynamic nonlinear change characteristics. Especially under transient conditions such as sharp turns and lane changes, the current signal will show short-term abnormal fluctuations, which are highly similar to the characteristics of a real phase loss fault. As a result, the detection method based on a fixed threshold is prone to misjudgment, affecting the accuracy of motor phase loss fault detection. Summary of the Invention

[0005] The present application provides a permanent magnet synchronous motor phase loss detection method, system, medium and product, which can improve the accuracy of permanent magnet synchronous motor phase loss fault detection.

[0006] In a first aspect, the present application provides a method for detecting phase loss in a permanent magnet synchronous motor, the method comprising: obtaining the real-time three-phase current and real-time load state of the steering motor, the real-time three-phase current comprising phase A current, phase B current and phase C current; multiplying the absolute value of the real-time three-phase current by a preset coefficient corresponding to the real-time load state to obtain a target three-phase current; accumulating and calculating the target three-phase currents respectively to obtain a three-phase current cumulative sum, the cumulative calculation being to accumulate and calculate the target currents of phase A, phase B and phase C obtained at different time points respectively to obtain the cumulative sum of the A phase current, the cumulative sum of the B phase current and the cumulative sum of the C phase current; when there is a current cumulative sum in the three-phase current cumulative sum that exceeds a preset cumulative sum threshold, or When the steering wheel steering angle of the target vehicle corresponding to the steering motor changes, the three-phase current cumulative sum is reset to the preset three-phase current cumulative sum; the current cumulative sum of any two phases is selected from the A-phase current cumulative sum, the B-phase current cumulative sum, and the C-phase current cumulative sum, and the relatively larger current cumulative sum is divided by the relatively smaller current cumulative sum to obtain a cumulative ratio set, which includes the cumulative ratios between phase A and phase B, phase A and phase C, and phase B and phase C; the ratio threshold corresponding to each cumulative ratio in the cumulative ratio set is obtained; it is determined whether the cumulative ratio exceeds the ratio threshold; if so, the number of phase loss times is increased by one; if not, the number of phase loss times is set to zero; when the number of phase loss times exceeds the preset number threshold corresponding to the real-time load state, an early warning strategy is executed.

[0007] By adopting the above technical solution, by obtaining the real-time load status and adjusting the preset coefficients when calculating the three-phase current accordingly, it is possible to adapt to the operating characteristics of the steering motor under different loads and reduce the interference of current fluctuations caused by load changes on the detection results. In the process of calculating the cumulative sum of the three-phase current, it is reset according to whether the current cumulative sum exceeds the preset threshold and the steering angle change of the steering wheel, thereby avoiding the impact of cumulative sum data overflow and steering angle change on phase loss fault detection. At the same time, by calculating the ratio of the cumulative sums of the currents of different phases and comparing them with the corresponding thresholds, and combining the number of phase losses and the preset number thresholds for judgment, the impact of abnormal fluctuations under transient conditions on phase loss fault detection is avoided, the accuracy of permanent magnet synchronous motor phase loss fault detection is improved, the system anomalies caused by misjudgment are reduced, and the reliability and safety of motor operation in application scenarios such as new energy vehicle steering systems are guaranteed.

[0008] In combination with some embodiments of the first aspect, in some embodiments, obtaining the ratio threshold corresponding to each cumulative ratio in the cumulative ratio set specifically includes: determining a preset three-phase current based on a current steering wheel steering angle, a current speed of the target vehicle, and a current wheel steering angle, the preset three-phase current being the three-phase current required by the steering motor to enable the wheel to steer according to a steering angle corresponding to the steering wheel steering angle; substituting the preset three-phase current, the current vehicle speed, the preset wheel steering angle corresponding to the current steering wheel steering angle, and the current wheel steering angle into a ratio threshold calculation formula to obtain the ratio threshold corresponding to each cumulative ratio in the cumulative ratio set; The calculation formula for the ratio threshold is: in, is the ratio threshold corresponding to the cumulative ratio obtained by dividing the X-phase current cumulative sum by the Y-phase current cumulative sum, η1 is the current loss rate of the current transmitted from the battery to the X-phase in the steering motor, η2 is the current loss rate of the current transmitted from the battery to the Y-phase in the steering motor, t is the number of accumulations of the cumulative sum, I X,set (τ) is the preset current of phase X when the cumulative number of times is τ, I Y,set (τ) is the preset current of the Y phase when the cumulative number of times is τ, γ1 is the high-frequency noise gain coefficient of the X phase, γ2 is the high-frequency noise gain coefficient of the Y phase, λ is the steering compensation gain coefficient, θ is the preset wheel steering angle corresponding to the current steering wheel steering angle, θ actual is the current wheel steering angle, θ max is the maximum allowable steering angle deviation, α is the vehicle speed adjustment reference value, β is the vehicle speed adjustment sensitivity coefficient, v is the current vehicle speed, and v0 is the vehicle speed threshold.

[0009] The above technical solution determines the preset three-phase current by combining the current steering wheel angle, vehicle speed, and wheel steering angle, thus accounting for the steering motor's current demand under actual operating conditions. Substituting these key parameters into the ratio threshold calculation formula, the system integrates multiple factors, including current loss rate, high-frequency noise gain coefficient, steering deviation, and vehicle speed. This ensures that the ratio thresholds corresponding to each cumulative ratio in the resulting cumulative ratio set are more consistent with the motor's operating characteristics under different operating conditions. This avoids the problem of misjudgment caused by varying operating conditions when using fixed thresholds, thereby improving the accuracy of detecting phase loss faults in permanent magnet synchronous motors.

[0010] In combination with some embodiments of the first aspect, in some embodiments, after the step of increasing the number of phase loss times by one, the method further includes: inputting the real-time three-phase current into a simulation model to simulate and obtain a first wheel steering angle of the target vehicle, and inputting the preset three-phase current into the simulation model to obtain a second wheel steering angle; when the first similarity between the actual wheel steering angle of the target vehicle and the first wheel steering angle is less than a preset first threshold, calculating the second similarity between the actual wheel steering angle and the second wheel steering angle; when the second similarity is greater than a preset second threshold, setting the number of phase loss times to zero.

[0011] By adopting the above technical solution, the real-time three-phase current and the preset three-phase current are respectively input into the simulation model to obtain the first wheel steering angle and the second wheel steering angle, and the similarity is compared with the actual wheel steering angle, thereby avoiding the misjudgment of phase loss caused by the failure of the sensor for collecting the real-time three-phase current, and improving the accuracy of the permanent magnet synchronous motor phase loss fault detection.

[0012] In combination with some embodiments of the first aspect, in some embodiments, after the step of executing the early warning strategy when the number of phase failures exceeds the preset number threshold corresponding to the real-time load state, the method also includes: when it is detected that the target vehicle is still driving within a preset time period and the steering motor is a single-phase fault, obtaining the driving direction of the lane where the target vehicle is located; when the driving direction includes turning, determining the steering probability of the target vehicle successfully turning when the steering motor is missing a phase according to the fault condition of the steering motor; when the steering probability is less than the preset threshold, prompting the driver of the target vehicle to drive straight or stop through the on-board display screen or speaker.

[0013] By adopting the above technical solution, the vehicle's driving status is further monitored after the phase loss fault warning. When it is detected that the vehicle continues to travel within a preset time (that is, when the vehicle cannot stop in time due to reasons such as excessive traffic flow) and the steering motor is a single-phase fault, the driving lane direction is obtained. If it is turning, by determining the probability of successful steering, the safety of vehicle steering when the steering motor is missing a phase can be accurately evaluated. When the steering probability is lower than the preset threshold, the driver is promptly prompted to drive in a straight line or stop through the on-board display or speaker, which can avoid traffic accidents caused by steering failure due to a phase loss of the steering motor, ensure the safety of the driver and the vehicle, and improve the driving safety and controllability of the vehicle in a faulty state.

[0014] In combination with some embodiments of the first aspect, in some embodiments, when the driving direction includes turning, the steering probability of the target vehicle that the steering motor is successfully turned is determined when the steering motor is missing a phase, specifically including: when the driving direction includes turning, obtaining the target wheel steering angle required for the target vehicle to perform the steering operation and the steering time corresponding to the target wheel steering angle; determining the target force for the driver of the target vehicle to turn the steering wheel to the target steering wheel steering angle corresponding to the target wheel steering angle according to the fault condition of the steering motor; determining the normal operating time of the normal phase of the steering motor running according to the current corresponding to the target wheel steering angle according to the fault condition of the steering motor; and calculating the steering probability of the target vehicle that the steering motor is successfully turned when the steering motor is missing a phase according to the target force, the steering time and the normal operating time.

[0015] By adopting the above technical solution, when the vehicle is turning, the basic requirements of the steering operation can be clarified by obtaining the target wheel steering angle and steering time. The target force of the target steering wheel steering angle and the normal operating time of the normal phase current are determined in combination with the steering motor failure situation, and the probability of successful steering is calculated by combining multiple factors. This method comprehensively considers key factors such as the human operation force and time during the steering operation and the operation status under the motor failure state, so that the calculated probability of successful steering is more in line with the actual working conditions, providing a reliable basis for subsequent prompts to the driver based on the steering probability, improving the accuracy and reliability of the vehicle's driving safety assessment when the steering motor is out of phase, and reducing the risk of accidents caused by steering failures.

[0016] In combination with some embodiments of the first aspect, in some embodiments, after the step of executing the early warning strategy when the number of phase failures exceeds the preset number threshold corresponding to the real-time load state, the method also includes: when it is detected that the target vehicle is still driving within a preset time period and the steering motor has a two-phase or three-phase fault, determining the straight route of the target vehicle according to the current position of the target vehicle; when there is a target area in the straight route, prompting the driver of the target vehicle to drive to the target area along the straight route and park through the on-board display screen or speaker.

[0017] With the above technical solution, after executing the early warning strategy, the vehicle's driving status is continuously monitored. When it is found that the vehicle is still driving within the preset time (that is, when the vehicle cannot be stopped in time due to reasons such as excessive traffic flow) and the steering motor is in a more serious condition such as a two-phase or three-phase fault, the straight route is determined based on the current position of the vehicle. If there is a target area on the straight route, the driver is promptly guided to drive to the target area and park along the route through the on-board display or speaker. This measure can avoid vehicle loss of control due to serious motor failure, reduce the risk of traffic accidents during the fault period, ensure the safety of the driver and surrounding personnel, and also create conditions for the subsequent proper handling of the faulty vehicle, thereby improving the scientificity and safety of vehicle failure response.

[0018] In combination with some embodiments of the first aspect, in some embodiments, after the step of executing the early warning strategy when the number of phase failures exceeds the preset number threshold corresponding to the real-time load state, the method also includes: obtaining the real-time position of the target vehicle; when the target vehicle turns at the traffic light intersection and the distance between the real-time position and the stop line of the traffic light intersection is within a preset distance range, controlling all traffic lights at the traffic light intersection to be red; when it is detected that there is no vehicle at the traffic light intersection, controlling the traffic light at the traffic light intersection corresponding to the driving direction of the target vehicle to be green.

[0019] Using this technical solution, when a vehicle is about to turn at a traffic light ahead of it, the system calculates the distance between the vehicle and the stop line at the intersection. If the distance is within a preset range, meaning there are no other vehicles between the vehicle and the stop line, the traffic light is controlled to display red, forcing the vehicle to stop at the stop line. When there are no vehicles at the intersection, only the traffic light in the direction of travel of the vehicle turns green. This prevents the vehicle from losing control when turning at the intersection due to a motor phase loss fault, potentially leading to a collision with vehicles traveling in the other direction. This reduces the probability of accidents involving vehicles with phase loss faults while passing through the intersection.

[0020] In a second aspect, an embodiment of the present application provides a vehicle control system comprising: one or more processors and a memory; the memory is coupled to the one or more processors, the memory being used to store computer program code, the computer program code comprising computer instructions, the one or more processors calling the computer instructions to enable the vehicle control system to execute the method described in the first aspect and any possible implementation of the first aspect.

[0021] In a third aspect, an embodiment of the present application provides a computer-readable storage medium comprising instructions, which, when executed on a vehicle control system, causes the vehicle control system to execute the method described in the first aspect and any possible implementation of the first aspect.

[0022] In a fourth aspect, the present application provides a computer program product, which, when executed on a vehicle control system, enables the vehicle control system to execute the method described in the first aspect and any possible implementation of the first aspect.

[0023] It is understood that the vehicle control system provided in the second aspect, the storage medium provided in the third aspect, and the computer program product provided in the fourth aspect are all used to execute the method provided in this application. Therefore, the beneficial effects achievable by these methods can be referenced to the beneficial effects of the corresponding methods and will not be further elaborated here.

[0024] One or more technical solutions provided in the embodiments of this application have at least the following technical effects or advantages: 1. This application calculates the ratio of the cumulative sum of currents of different phases and compares it with the dynamic ratio threshold calculated according to the ratio threshold calculation formula, and makes a judgment based on the number of phase loss and the preset number threshold. It avoids the influence of abnormal fluctuations on phase loss fault detection under transient working conditions and the misjudgment problem caused by changes in working conditions when using fixed thresholds, thereby improving the accuracy of phase loss fault detection in permanent magnet synchronous motors.

[0025] 2. This application accurately assesses vehicle steering safety when a steering motor phase is missing by calculating the probability of successful steering. When the steering probability falls below a preset threshold, the driver is promptly prompted via the onboard display or speakers to drive straight or stop. This prevents traffic accidents caused by steering failure due to a steering motor phase loss, ensures driver and vehicle safety, and improves vehicle safety and controllability during fault conditions.

[0026] 3. When the present application detects that there are no vehicles at the traffic light intersection where the vehicle is turning, it only controls the traffic light at the intersection in the same direction as the vehicle's travel to turn green, allowing the vehicle and other vehicles behind the vehicle in the same direction of travel to continue turning, thereby avoiding the risk of the vehicle losing control when turning at the intersection due to a motor phase failure, and colliding with vehicles traveling normally in other directions, thereby reducing the probability of traffic accidents involving vehicles with phase failures when passing through the intersection. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a structural diagram of a system architecture to which the permanent magnet synchronous motor phase loss detection method according to an embodiment of the present application can be applied; Figure 2 This is a flow chart of a method for detecting phase loss in a permanent magnet synchronous motor according to an embodiment of the present application; Figure 3 This is another flow chart of the method for detecting phase loss in a permanent magnet synchronous motor according to an embodiment of the present application; Figure 4It is a schematic diagram of an exemplary hardware structure of a vehicle control system in an embodiment of the present application. DETAILED DESCRIPTION

[0028] The terms used in the following examples of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. As used in the specification and appended claims of this application, the singular expressions "a," "an," "said," "above," "the," and "this" are intended to include plural expressions as well, unless the context clearly indicates otherwise. It should also be understood that the term "and / or" used in this application refers to any or all possible combinations comprising one or more of the listed items.

[0029] In the following, the terms "first" and "second" are used for descriptive purposes only and should not be understood to imply or suggest relative importance or implicitly indicate the number of the technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of this application, unless otherwise specified, "plurality" means two or more.

[0030] Figure 1 It is a structural diagram of a system architecture to which the permanent magnet synchronous motor phase loss detection method in the embodiment of the present application can be applied.

[0031] See also Figure 1 ,The vehicle control system includes sensors, on-board displays, speakers and vehicle controllers.

[0032] The vehicle controller, the core component of the system, analyzes and processes the three-phase current data collected by the sensor, detects any phase loss in the steering motor, and sends control commands to the onboard display and speaker. The sensor collects the three-phase current of the steering motor and transmits the collected test data to the vehicle controller. The onboard display receives control commands from the vehicle controller and displays corresponding prompts. The speaker receives control commands from the vehicle controller and plays corresponding prompts.

[0033] Through the above system architecture, the vehicle control system can detect the phase loss fault of the steering motor based on the real-time three-phase current collected by the sensor, and when the steering motor has a phase loss fault, it will remind the vehicle driver through the on-board display and speaker.

[0034] In the related art, it is usually determined whether the motor has a phase loss fault by real-time monitoring of the three-phase current of the motor. A common judgment method is to set a current threshold. When the current of a certain phase is lower than the set threshold for a continuous period of time, it is determined that the motor has a phase loss fault. Another method is to calculate the average value of the absolute value of the three-phase current over a period of time, and detect the ratio of its maximum value to the minimum value. If the ratio exceeds the preset threshold, it is determined that the motor has a phase loss fault. However, since the load and speed of the steering motor change rapidly when the vehicle is turning, the amplitude and phase relationship of the three-phase current are not fixed, but show dynamic nonlinear change characteristics. Especially under transient conditions such as sharp turns and lane changes, the current signal will have short-term abnormal fluctuations, which are highly similar to the characteristics of the actual phase loss fault. As a result, the detection method based on a fixed threshold is prone to misjudgment, affecting the accuracy of motor phase loss fault detection.

[0035] The permanent magnet synchronous motor phase loss detection method in the embodiment of the present application is adopted. By calculating the ratio of the accumulated sums of currents of different phases and comparing it with the preset dynamic ratio threshold value corresponding to the real-time three-phase current of the steering motor, the judgment is made based on the number of phase losses and the preset number threshold value. This avoids the influence of abnormal fluctuations under transient working conditions on phase loss fault detection and the misjudgment problem caused by changes in working conditions when using fixed thresholds, thereby improving the accuracy of permanent magnet synchronous motor phase loss fault detection.

[0036] The following combination Figure 2 To illustrate the method of the embodiment of the present application.

[0037] See also Figure 2 , which is a flow chart of a method for detecting phase loss in a permanent magnet synchronous motor in an embodiment of the present application.

[0038] S201. Acquire the real-time three-phase current and real-time load status of the steering motor.

[0039] The real-time three-phase current includes phase A current, phase B current, and phase C current.

[0040] Specifically, the system communicates with current sensors installed in the steering motor circuit to obtain real-time three-phase currents. These current sensors utilize high-precision Hall-effect current sensors, capable of accurately and in real time measuring the current values in the motor's three-phase circuit. Alternatively, the system communicates with current sensors installed in the steering motor circuit to obtain real-time currents for two of the three phases. Based on these two acquired currents, the third-phase current is calculated, taking into account the characteristic that the sum of the three-phase currents is zero.

[0041] After obtaining the three-phase current, the real-time three-phase current is normalized with the rated current of the steering motor as the base value, and the real-time three-phase current is represented by the Q15 format fixed point (represented by a signed 16-bit integer). Normalization is to represent the actual physical quantity with the relative value of its base value. Here, the rated current of the steering motor is used as the base value. The calculation formula of the normalized value is: Normalized value = real-time current / rated current. Q15 format is a 16-bit fixed-point number representation method, in which the highest bit is the sign bit and the remaining 15 bits are the value bits. The steps to convert the normalized value to Q15 format are as follows: multiply the normalized value by 2 15 (Because the range represented by the Q15 format is [-1,1), multiply by 2 15 is to map it to the range of 16-bit integers).

[0042] To obtain the real-time load status, the system uses a torque sensor installed on the steering motor for measurement. The torque sensor monitors the torque applied to the motor during operation in real time, which reflects the load condition of the steering motor. The torque sensor converts the detected torque signal into an electrical signal and transmits it to the system via a signal line. Based on the received torque digital signal and the motor speed information (which can be obtained through a speed sensor installed on the motor shaft), the system calculates the current real-time load status of the steering motor, such as light load, medium load, or heavy load, according to a specific algorithm (for example, based on the motor's mechanical characteristic curve).

[0043] S202 : Multiply the absolute value of the real-time three-phase current by a preset coefficient corresponding to the real-time load state to obtain a target three-phase current.

[0044] Specifically, the preset coefficient corresponding to the real-time load state is searched in the preset coefficient correspondence table. The absolute value of the real-time three-phase current of phase A is multiplied by the preset coefficient, the absolute value of the phase B is multiplied by the preset coefficient, and the absolute value of the phase C is multiplied by the preset coefficient (such as 1000, which affects the speed of output phase loss judgment) to obtain the target current of phase A, phase B, and phase C.

[0045] The preset coefficient correspondence table is created by building a simulated vehicle steering system test platform, classifying load states into light, medium, and heavy loads, and setting various operating conditions. Real-time data collection, including three-phase current and load torque, is used. After preprocessing, the preset coefficients corresponding to each load state are calculated using data fitting and optimization algorithms based on the performance requirements of the motor and steering system. This is then verified and adjusted experimentally. The absolute value of the real-time three-phase current is multiplied by the preset coefficient to achieve rapid accumulation of current values, improving the efficiency of phase loss detection.

[0046] S203 , cumulatively calculating the target three-phase currents respectively to obtain a cumulative sum of the three-phase currents.

[0047] Specifically, the cumulative calculation is to accumulate the target current of phase A, the target current of phase B and the target current of phase C obtained at different time points to obtain the cumulative sum of phase A current, the cumulative sum of phase B current and the cumulative sum of phase C current.

[0048] Specifically, when a new target three-phase current is obtained, the internally stored cumulative sum of the A-phase current is added to the newly obtained A-phase target current, the internally stored cumulative sum of the B-phase current is added to the newly obtained B-phase target current, and the internally stored cumulative sum of the C-phase current is added to the newly obtained C-phase target current to obtain the accumulated sum of the A-phase current, the B-phase current, and the C-phase current.

[0049] The internally stored A-phase current accumulation sum is updated each time it is accumulated, and is updated to the value obtained by the last accumulation.

[0050] S204. When a current cumulative sum in the three-phase current cumulative sum exceeds a preset cumulative sum threshold, or a steering wheel steering angle of the target vehicle corresponding to the steering motor changes, the three-phase current cumulative sum is reset to a preset three-phase current cumulative sum.

[0051] Specifically, after each accumulation operation, the accumulated current sums of phase A, phase B, and phase C are compared with a preset accumulated current threshold. If any of the three-phase current accumulated sums exceeds the preset accumulated current threshold, the three-phase current accumulated sums are reset to the preset three-phase current accumulated sum to avoid data overflow and false phase loss detection.

[0052] Simultaneously, the steering wheel angle of the target vehicle's driver is acquired in real time. The system establishes a connection with the angle sensor mounted on the steering mechanism and acquires the real-time steering wheel angle transmitted by the angle sensor. When the difference between the real-time steering wheel angle and the last acquired steering wheel angle exceeds a preset threshold (i.e., a change in the steering wheel angle), indicating a change in the target vehicle's steering condition, the three-phase current cumulative sum is reset to the preset three-phase current cumulative sum, ensuring accurate phase loss detection under the new operating conditions.

[0053] S205 , selecting the current cumulative sums of any two phases from the current cumulative sums of phase A, phase B, and phase C, and dividing the relatively larger current cumulative sum by the relatively smaller current cumulative sum to obtain a cumulative ratio set.

[0054] The cumulative ratio set includes the cumulative ratios between phase A and phase B, phase A and phase C, and phase B and phase C.

[0055] Specifically, the cumulative sum of the currents of phase A and phase B is obtained, the two cumulative sums are compared, and the larger cumulative sum is divided by the smaller cumulative sum to obtain the cumulative ratio of phase A to phase B. Then, the cumulative ratios of phase A to phase C and phase B to phase C are calculated in the same manner.

[0056] S206: Obtain a ratio threshold corresponding to each accumulated ratio in the accumulated ratio set.

[0057] Specifically, the system first establishes a communication connection with an angle sensor mounted on the steering wheel mechanism, receiving data transmitted by the angle sensor in real time to obtain the current steering angle of the target vehicle. Next, the system obtains the current speed of the target vehicle as captured by a speed sensor. Speed sensors are typically mounted on wheels or the drivetrain, enabling real-time monitoring of vehicle speed. Finally, the system obtains the current steering angle of the target vehicle as captured by the angle sensor. An angle sensor mounted on the steering wheel mechanism measures the actual steering angle of the wheel in real time.

[0058] Based on the current steering wheel angle, vehicle speed, and wheel steering angle, a complex algorithm is used to calculate the preset three-phase current, in accordance with the vehicle dynamics model and relevant steering system parameters. This preset three-phase current is the value of the three-phase current required by the steering motor to ensure the wheels accurately steer according to the steering wheel angle. First, the theoretical torque required by the motor is calculated based on the actual steering angle difference between the steering wheel and the wheels (steering demand), the current vehicle speed, and vehicle dynamics (such as steering resistance and tire aligning torque). This theoretical torque must overcome the inertia, friction, and external load of the steering system to ensure that the wheels accurately follow the steering wheel. Next, the required torque is converted into the current reference value required for motor control. Since the torque of a permanent magnet synchronous motor is primarily determined by its q-axis current, the system prioritizes the q-axis current, while the d-axis current is typically set to zero to improve efficiency. Finally, through coordinate transformation (converting from the rotating dq coordinate system back to the stationary three-phase coordinate system), a reference waveform of the three-phase current (phases A, B, and C) is generated. Its amplitude and phase are determined by the real-time position of the motor rotor.

[0059] In some embodiments, a pre-calibrated three-dimensional lookup table (LUT) may be used to directly query the corresponding preset three-phase current based on the combination of steering wheel angle, vehicle speed, and wheel angle.

[0060] After determining the preset three-phase current, a pre-stored threshold value correspondence table is searched for a record matching the preset three-phase current to obtain the ratio threshold corresponding to each cumulative ratio in the cumulative ratio set. The threshold value correspondence table records the correspondence between different preset three-phase currents and ratio thresholds.

[0061] S207: Determine whether any accumulated ratio exceeds a ratio threshold.

[0062] If so, execute step S208 to increase the number of phase loss times by one; if not, execute step S209 to set the number of phase loss times to zero.

[0063] Specifically, the cumulative ratios of phases A and B are compared with corresponding ratio thresholds, the cumulative ratios of phases A and C are compared with corresponding ratio thresholds, and the cumulative ratios of phases B and C are compared with corresponding ratio thresholds. If one or more cumulative ratios in the cumulative ratio sets of phases A and B, phases A and C, and phases B and C exceed the corresponding ratio thresholds, it is determined that the cumulative ratios exceed the ratio thresholds. If no cumulative ratios in the cumulative ratio sets exceed the corresponding ratio thresholds, it is determined that no cumulative ratios exceed the ratio thresholds.

[0064] S208: Increase the number of phase loss times by one.

[0065] If the accumulated ratio exceeds the ratio threshold, the internally stored value of the number of phase failures is increased by one.

[0066] S209: Set the number of phase loss times to zero.

[0067] If there is no accumulated ratio exceeding the ratio threshold, the value of the number of phase failures stored internally is reset to zero.

[0068] S210: When the number of phase failures exceeds a preset threshold corresponding to the real-time load state, execute an early warning strategy.

[0069] Specifically, when the number of phase losses exceeds a preset threshold corresponding to the real-time load status, the early warning strategy is executed. First, the system sends a fault code to the instrument panel, triggering the yellow warning light to flash, and records the fault information to the vehicle event data recorder. Subsequently, the system takes appropriate protective measures based on the severity of the phase loss. For mild phase loss (single-phase loss), the system limits the motor output power to a safe range; for severe phase loss (two or three-phase loss), the system immediately cuts off the motor power supply and switches to mechanical steering mode.

[0070] During the execution of the early warning strategy, the system will continuously monitor the motor status. If the phase loss phenomenon is detected to disappear within the specified time, the partial power assist function will be automatically restored; if the phase loss persists, the protection state will be maintained until the vehicle is turned off and restarted.

[0071] In the embodiment of the present application, by obtaining the real-time load status and adjusting the preset coefficients when calculating the three-phase current accordingly, the operating characteristics of the steering motor under different loads can be adapted, and the interference of current fluctuations caused by load changes on the detection results can be reduced. In the process of calculating the cumulative sum of the three-phase current, the current cumulative sum is reset according to whether it exceeds the preset threshold and the steering angle of the steering wheel changes, thereby avoiding the influence of cumulative sum data overflow and steering angle changes on the detection of phase loss faults. At the same time, by calculating the ratio of the cumulative sums of the currents of different phases and comparing it with the preset dynamic ratio threshold corresponding to the real-time three-phase current of the steering motor, and combining the number of phase loss and the preset number threshold for judgment, the influence of abnormal fluctuations under transient working conditions on the detection of phase loss faults and the misjudgment problem caused by changes in working conditions when a fixed threshold is used are avoided, thereby improving the accuracy of the detection of phase loss faults of permanent magnet synchronous motors.

[0072] The following combination Figure 3 To further illustrate the method of the embodiment of the present application.

[0073] See also Figure 3 , is another flow chart of the permanent magnet synchronous motor phase loss detection method in an embodiment of the present application.

[0074] S301 : Acquire the real-time three-phase current and real-time load status of the steering motor.

[0075] S302 : Multiply the absolute value of the real-time three-phase current by a preset coefficient corresponding to the real-time load state to obtain a target three-phase current.

[0076] S303: Accumulate and calculate the target three-phase currents respectively to obtain a three-phase current accumulation sum.

[0077] S304: When a current cumulative sum in the three-phase current cumulative sum exceeds a preset cumulative sum threshold, or a steering wheel steering angle of the target vehicle corresponding to the steering motor changes, the three-phase current cumulative sum is reset to a preset three-phase current cumulative sum.

[0078] S305 , selecting the current cumulative sums of any two phases from the current cumulative sums of phase A, phase B, and phase C, and dividing the relatively larger current cumulative sum by the relatively smaller current cumulative sum to obtain a cumulative ratio set.

[0079] S306 : Determine a preset three-phase current according to the current steering wheel angle, the current speed of the target vehicle, and the current wheel steering angle.

[0080] The preset three-phase current is the three-phase current required by the steering motor to enable the wheels to steer according to the steering angle corresponding to the steering angle of the steering wheel.

[0081] Steps S301-S306 and Figure 2Steps S201 to S206 in the illustrated embodiment are similar, and reference may be made to the description of steps S201 to S206 , which will not be repeated here.

[0082] S307. Substitute the preset three-phase current, the current vehicle speed, the preset wheel steering angle corresponding to the current steering wheel steering angle, and the current wheel steering angle into the ratio threshold calculation formula to obtain the ratio threshold corresponding to each cumulative ratio in the cumulative ratio set.

[0083] The ratio threshold calculation formula is: in, is the ratio threshold corresponding to the cumulative ratio obtained by dividing the X-phase current cumulative sum by the Y-phase current cumulative sum, η1 is the current loss rate of the current transmitted from the battery to the X-phase in the steering motor, η2 is the current loss rate of the current transmitted from the battery to the Y-phase in the steering motor, t is the number of accumulations of the cumulative sum, I X,set (τ) is the preset current of phase X when the cumulative number of times is τ, I Y,set (τ) is the preset current of the Y phase when the cumulative number of times is τ, γ1 is the high-frequency noise gain coefficient of the X phase, γ2 is the high-frequency noise gain coefficient of the Y phase, λ is the steering compensation gain coefficient, θ is the preset wheel steering angle corresponding to the current steering wheel steering angle, θ actual is the current wheel steering angle, θ max is the maximum allowable steering angle deviation, α is the vehicle speed adjustment reference value, β is the vehicle speed adjustment sensitivity coefficient, v is the current vehicle speed, and v0 is the vehicle speed threshold.

[0084] In the ratio threshold calculation formula, The ratio threshold corresponding to the cumulative ratio obtained by dividing the X-phase current cumulative sum by the Y-phase current cumulative sum. When calculating the ratio threshold corresponding to the cumulative ratio of phases A and B, phase X is the phase corresponding to the larger of the two current cumulative sums, and phase Y is the phase corresponding to the smaller of the two current cumulative sums. The ratio threshold corresponding to the cumulative ratio of phases A and C, and the ratio threshold corresponding to the cumulative ratio of phases B and C, are determined in the same manner as described above in the calculation formula.

[0085] in the formula The first part is an integral calculation of the ratio of the X-phase preset current to the Y-phase preset current from the initial cumulative number t0 to the current cumulative number t, taking into account the current loss rate and the high-frequency noise gain coefficient.

[0086] in, This shows the current relationship between the X-phase and the Y-phase when considering the current loss and high-frequency noise gain. X,set (τ)|| 2+γ1 reflects the situation of X-phase current under the influence of transmission loss and high-frequency noise, η2||I Y,set (τ)|| 2 +γ2 corresponds to the Y phase. This ratio reflects the relative magnitude of the two-phase current under the influence of loss and noise. Integrating this ratio accumulates the relative relationship of the two-phase currents from the start to the current accumulation time. This takes into account the dynamic changes in the current relationship throughout the process and can more comprehensively reflect the comprehensive situation of the two-phase currents in the steering motor being affected by loss and noise at different stages. Its advantage is that this integral form takes into account the current change factor in the time dimension. Compared with only considering the current relationship at a certain moment, it can more accurately reflect the comprehensive characteristics of the current during system operation, providing a data basis that is more in line with the actual operating conditions for the subsequent calculation of the ratio threshold, which helps to improve the accuracy and reliability of steering system-related control and monitoring.

[0087] in the formula The tanh() function is a hyperbolic tangent function that can be used to calculate the compensation of the steering angle deviation. The ratio of the absolute value of the deviation between the preset wheel steering angle and the current wheel steering angle corresponding to the current steering wheel angle and the maximum allowable steering angle deviation is mapped to the (-1, 1) interval, providing a nonlinear scaling effect on the angle deviation. λ is the steering compensation gain factor, which weights the impact of the scaled angle deviation. This allows for dynamic compensation adjustments to the comparison threshold based on the deviation between the actual steering angle and the preset angle, enabling better adaptation to diverse steering conditions and improving the system's sensitivity and accuracy in detecting and responding to steering angle anomalies.

[0088] in the formula Part of it is the adjustment calculation considering the vehicle speed factor. This function is based on vehicle speed, a speed threshold, and a speed control sensitivity coefficient, and it takes on values within a certain range depending on vehicle speed. α is the speed control reference value, and the results of this component are weighted. When the vehicle speed approaches the speed threshold, the value of this component is dynamically adjusted based on the speed control reference value and the speed control sensitivity coefficient. This design enables the calculation of the ratio threshold to be adaptively adjusted based on vehicle speed. Because the operating characteristics of the steering system and the requirements for parameters such as current may vary at different vehicle speeds, this approach allows the system to more reasonably set the ratio threshold under different vehicle speed conditions.

[0089] In summary, the ratio threshold calculation formula comprehensively considers multiple factors, including current transmission loss, high-frequency noise, steering angle deviation, and vehicle speed. Through the synergistic effect of these parameters, this formula can scientifically and accurately calculate the ratio threshold corresponding to each cumulative ratio in the cumulative ratio set. This provides a reliable basis for determining factors such as permanent magnet synchronous motor phase loss detection, and improves the accuracy and stability of the system's operation monitoring and control under different operating conditions.

[0090] S308: Determine whether any accumulated ratio exceeds a ratio threshold.

[0091] If yes, execute step S309; if no, execute step S314.

[0092] S309: Increase the number of phase loss times by one.

[0093] Steps S308-S309 and Figure 2 Steps S207 and S208 in the illustrated embodiment are similar, and the descriptions of steps S207 and S208 may be referred to, which will not be repeated here.

[0094] S310: Input the real-time three-phase current into the simulation model to simulate and obtain a first wheel steering angle of the target vehicle.

[0095] Specifically, the real-time three-phase current of the steering motor, as measured by the sensor, is first acquired. This real-time three-phase current is then fed into the simulation model to determine the target vehicle's first wheel steering angle—the actual steering angle of the target vehicle's wheels under the current operating conditions (when the steering motor is operating according to the actual three-phase current measured by the sensor).

[0096] The simulation model is constructed based on the vehicle dynamics model and relevant parameters of the steering system. It includes mathematical models of components such as the steering motor, transmission mechanism, wheels, and the interaction between them.

[0097] The construction process begins with detailed mathematical modeling of various vehicle components, such as the steering motor, transmission mechanism (including the steering column and steering gear), wheels, and tires. For the steering motor, its electromagnetic characteristics and torque-current relationship must be considered; for the transmission mechanism, its mechanical transmission ratio and friction must be considered; and for the wheels and tires, rolling resistance and lateral deviation characteristics must be considered. By integrating the mathematical models of these components, a comprehensive model is established that describes the workings of the vehicle steering system.

[0098] Before training the model, a large amount of training data is required. By installing various sensors on the actual vehicle, such as angle sensors, speed sensors, and torque sensors, we can obtain actual operating data under different operating conditions, including steering wheel angle, vehicle speed, wheel steering angle, motor three-phase current, and motor output torque. Furthermore, key components such as the steering motor can be individually tested using experimental equipment to obtain characteristic data such as torque output under different current inputs. The collected data is then cleaned and preprocessed to obtain model training data.

[0099] During the model training process, the constructed model is trained using training data. By adjusting the parameters in the model (such as motor parameters, transmission mechanism parameters, etc.), the output of the model (such as the simulated wheel steering angle) is made as close as possible to the actual collected wheel steering angle.

[0100] When real-time three-phase current is input into the model, it first converts the current signal into a torque signal based on the motor's electromagnetic model. For example, for a permanent magnet synchronous motor, the output torque of the motor at that current input is calculated based on the torque-current relationship (e.g., torque is primarily determined by the q-axis current). After determining the motor's output torque, the model transmits the motor torque to the wheels based on the mathematical model of the transmission mechanism, taking into account factors such as the transmission ratio and friction. By calculating torque losses and angle conversion during the transmission process, the effective torque transmitted to the wheels and the corresponding angle change are calculated. Based on the mathematical models of the wheels and tires, factors such as rolling resistance and lateral deviation are taken into account, and combined with the effective torque transmitted to the wheels, the final steering angle of the wheels is further calculated. The model comprehensively considers the interaction of various factors and, through a series of mathematical calculations and logical judgments, ultimately outputs the target vehicle's first wheel steering angle.

[0101] S311 . Input a preset three-phase current into a simulation model to obtain a second wheel steering angle.

[0102] Specifically, the preset three-phase current of the steering motor is first obtained. Then, the preset three-phase current is input into the simulation model to obtain the second wheel steering angle of the target vehicle, that is, the steering angle value that the target vehicle's wheels should achieve under ideal operating conditions (when the steering motor operates according to the preset three-phase current).

[0103] S312: When a first similarity between the actual wheel steering angle of the target vehicle and the first wheel steering angle is less than a preset first threshold, calculate a second similarity between the actual wheel steering angle and the second wheel steering angle.

[0104] Specifically, first, an actual wheel steering angle of the target vehicle is acquired in real time by an angle sensor installed on the wheel steering mechanism, and a difference between the actual wheel steering angle and the first wheel steering angle is calculated.

[0105] Then, a suitable similarity calculation method (such as the cosine similarity algorithm) is used to calculate the first similarity. Taking the cosine similarity algorithm as an example, the actual wheel steering angle and the first wheel steering angle are respectively regarded as vectors in a vector space, and their similarity is measured by calculating the cosine value of the angle between the two vectors.

[0106] When the first similarity is greater than or equal to the preset first threshold, it means that the actual steering condition of the current wheel is slightly different from the steering condition under the current actual working condition (the steering motor operates according to the actual three-phase current collected by the sensor), the data collected by the sensor and the actual data are within the error range, and the steering abnormality of the target vehicle is caused by a phase loss in the steering motor.

[0107] When the first similarity is less than the preset first threshold, it means that the actual steering situation of the current wheel is significantly different from the steering situation under the current actual working conditions, and the error between the data collected by the sensor and the actual data is outside the error range, which may affect the phase loss judgment of the motor. Continue to calculate the second similarity between the actual wheel steering angle of the wheel and the second wheel steering angle (that is, the wheel steering angle value under ideal working conditions). Similarly, the above-mentioned similarity calculation method (such as the cosine similarity algorithm) is used to calculate the vector corresponding to the actual wheel steering angle and the vector corresponding to the second wheel steering angle to obtain the cosine value of the angle between them, that is, the second similarity.

[0108] S313: When the second similarity is greater than a preset second threshold, the number of phase loss times is set to zero.

[0109] When the first similarity is smaller than a preset first threshold value and the second similarity is larger than a preset second threshold value, the internally stored value of the number of phase failures is reset to zero.

[0110] Among them, the first similarity is less than the preset first threshold, and the second similarity is greater than the preset second threshold, indicating that the actual steering angle of the target vehicle's wheel is slightly different from the steering situation under ideal working conditions, but significantly different from the steering situation under actual working conditions. There is a large error between the real-time three-phase current data collected by the sensor and the three-phase current data of the steering motor in actual operation. The data collected by the sensor is inaccurate and there is a fault, but there is no phase loss fault in the steering motor.

[0111] S314: Set the number of phase loss times to zero.

[0112] S315: When the number of phase failures exceeds a preset threshold corresponding to the real-time load status, execute an early warning strategy.

[0113] Steps S314-S315 and Figure 2In the illustrated embodiment, steps S209 and S210 are similar, and the descriptions of steps S209 and S210 may be referred to, which will not be repeated here.

[0114] S316: When it is detected that the target vehicle is still moving within a preset time period and the steering motor has a single-phase fault, the driving direction of the lane where the target vehicle is located is obtained.

[0115] Specifically, the system communicates with the speed sensor installed on the wheel or transmission system to continuously obtain vehicle speed information. If the obtained vehicle speed is greater than a certain set speed threshold within a preset time period, it is determined that the vehicle is still moving. At the same time, it is determined whether the steering motor is in a single-phase fault state. When the cumulative ratio of only two sets of phase currents exceeds their corresponding ratio thresholds, it is determined that the steering motor is in a single-phase fault state. Alternatively, the real-time three-phase current of the steering motor is obtained and compared with the preset three-phase current. When the difference between the real-time three-phase current and the preset three-phase current exceeds the preset error range, the number of phases exceeding the error range is obtained. When the number of phases is one, it is determined that the steering motor is in a single-phase fault state.

[0116] If the target vehicle continues to move within a preset time period and the steering motor experiences a single-phase fault, the system obtains the target vehicle's direction of travel in the lane it is traveling in. The system uses the target vehicle's built-in positioning device to obtain the vehicle's real-time location. This real-time location is matched against a preset map database to determine the target vehicle's lane. To improve matching accuracy and efficiency, algorithms based on grid or spatial indexing can be used to quickly narrow the search scope and locate the vehicle's specific lane. This map database details the road's geographic coordinates and information such as the direction, slope, and curvature of each lane. After determining the target vehicle's lane, the system directly obtains the target vehicle's direction of travel from the map data.

[0117] In some embodiments, if multiple cameras are installed around the vehicle, the direction of travel of the target vehicle in the lane can be determined through image recognition.

[0118] First, the camera captures surrounding image information. Then, features such as lane markings, traffic signs (such as arrows), and road edges within the image are identified to determine the vehicle's lane direction. Lane marking identification uses algorithms such as edge detection and the Hough transform to extract geometric features, and then combines them with machine learning models to classify lane marking type and direction. For traffic sign recognition, deep learning-based object detection algorithms can be used to identify various traffic signs and determine lane direction based on the sign information.

[0119] S317: When the driving direction includes turning, obtain a target wheel steering angle required for the target vehicle to perform a steering operation and a steering duration corresponding to the target wheel steering angle.

[0120] Specifically, when the driving direction includes turning, the historical driving record of the target vehicle and the current speed of the target vehicle are obtained. The historical driving record contains the driving speed, wheel steering angle and corresponding turning duration of the target vehicle when turning in different lanes. A target driving record set is searched for a driving lane in each record of the historical driving record that is consistent with the current driving lane of the target vehicle. A target driving record is searched for a driving speed in each record of the target driving record set that is within a preset error range with the current speed. The wheel steering angle and corresponding turning duration in the target driving record are obtained as the target wheel steering angle and corresponding turning duration required for the target vehicle to perform the turning operation.

[0121] If no similar target driving records are found, the system first obtains information about the turning road ahead of the target vehicle from the map database, such as the curve radius, road length, and road slope. It then obtains vehicle information from the vehicle's own sensors and configuration database, including vehicle mass, wheelbase, track width, steering system stiffness, tire cornering stiffness, steering motor maximum speed, maximum torque, steering wheel rotation angle, steering motor torque, and vehicle speed.

[0122] Next, the steering angle is calculated. First, based on information such as the curve radius and road length, the turning road is divided into multiple sections based on the curvature change. For example, for curves with a small curvature radius change, the sections can be divided at equal distances. For curves with a large curvature radius change, the sections can be divided based on the rate of change of the curvature radius, with sections where the curvature radius changes rapidly being cut more finely to more accurately describe the turning process.

[0123] For each cut section, the steering angle can be calculated using the Ackerman model. The Ackerman model states that when a vehicle turns, the turning radius of the inner wheel and the outer wheel are different, and the relationship is: where θ in and θ out are the steering angles of the inner and outer wheels respectively, W is the wheelbase, and L is the wheelbase. Given the curvature radius R of the curve, assuming the vehicle travels along the centerline of the curve, the turning radius of the outer wheel can be approximately The turning radius of the inner wheel is Using trigonometric relationships, the steering angles of the inner and outer wheels can be calculated. This calculation does not take into account factors such as vehicle mass, road adhesion, steering system stiffness, and tire cornering stiffness. In actual calculations, the steering angle needs to be corrected based on these factors. This correction can be achieved by building a vehicle dynamics model that incorporates these factors to produce a more accurate steering angle calculation formula.

[0124] After determining the steering angle for each cut, the steering duration is calculated based on the vehicle's current speed. Assuming the vehicle maintains a constant speed within each cut, the steering duration is equal to the length of the road in the cut divided by the vehicle's current speed. Since the vehicle's steering system requires a certain amount of time from receiving a steering command to implementing the corresponding steering angle—this is known as the steering system's response time—this response time must be taken into account when calculating the steering duration. Generally speaking, the steering system's response time is related to factors such as the steering motor's maximum speed and maximum torque, as well as the stiffness of the steering system. This response time can be determined experimentally or by developing a dynamic model of the steering system. This response time can then be added to the steering duration for each cut to yield more accurate predictions.

[0125] S318. Determine, based on the fault condition of the steering motor, a target force for the driver of the target vehicle to turn the steering wheel to a target steering wheel steering angle corresponding to the target wheel steering angle.

[0126] Specifically, the phase of the steering motor with a single-phase fault is first determined. The real-time three-phase current of the steering motor is obtained and compared with the preset three-phase current. The difference between the currents of each phase is calculated. If the difference between the current of a particular phase and the preset current of that phase in the preset three-phase current exceeds a preset error range, that phase is determined to be the faulty phase.

[0127] Next, calculate the current available torque of the rotating motor. Obtain the preset steering angle-current relationship table corresponding to the normal state (the table is calibrated through bench tests and records the optimized distribution scheme of the two-phase current at different steering angles). The normal phases are the other two phases except the faulty phase. Next, find the current of the normal phase corresponding to the maximum steering angle in the steering angle-current relationship table. If the angle is between the discrete values listed in the table, use linear interpolation to calculate the current value. Then, retrieve key parameters such as the torque constant of the remaining two normal phases from the motor characteristic database. Finally, substitute the current value and torque constant of the normal phase into the permanent magnet synchronous motor torque formula (Where T is the motor torque, p is the number of motor pole pairs, ψ f is the permanent magnet flux, i d 、i q are the d-axis and q-axis currents, L d 、L q are the d-axis and q-axis inductances respectively), and calculate the maximum torque that the motor can provide under fault conditions.

[0128] Next, the theoretical torque required to complete the steering operation, corresponding to the target wheel steering angle and the current speed of the target vehicle, is obtained from a preset torque mapping table. The torque gap is calculated and converted into the additional torque required by the driver. The theoretical torque is subtracted from the motor's current maximum available torque to determine the additional torque required by the driver through the steering wheel. Based on the steering system's transmission ratio and mechanical efficiency, a preset formula is used to calculate the additional steering wheel force corresponding to this torque gap.

[0129] Finally, the target force is obtained by adding the preset normal force corresponding to the target wheel steering angle to the additional force.

[0130] S319: Determine, based on the fault condition of the steering motor, a normal operating time of a normal phase of the steering motor operating at a current corresponding to the target wheel steering angle.

[0131] Specifically, the maximum steering angle among the target wheel steering angles is selected. Then, the normal phase current corresponding to the maximum steering angle is obtained from the normal phase steering angle-current relationship table. If the angle falls between the discrete values listed in the table, the normal phase current value is calculated using linear interpolation.

[0132] The system first obtains the real-time temperature of the steering motor collected by the temperature sensor installed on the steering motor. At the same time, the thermal characteristic parameters of the motor, such as the thermal time constant and thermal resistance, are retrieved from the technical parameter library of the steering motor. These parameters reflect the characteristics of the motor during the heating and heat dissipation process. Based on the real-time temperature, thermal characteristic parameters and the normal phase current currently found, the thermal model is used to estimate the temperature rise of the motor under the continuous action of the current. The thermal model takes into account the influence of current size, time and environmental factors on the motor temperature, and simulates the trend of motor temperature change over time. During the simulation process, the maximum temperature allowed by the motor is used as the limiting condition. When the simulated motor temperature reaches the maximum temperature, the corresponding time is the first normal operating time of the steering motor calculated based on the thermal characteristics.

[0133] At the same time, the system determines the second normal operating duration of the steering motor based on the steering motor's historical operating data and current operating conditions. First, the system obtains the steering motor's current operating conditions, including factors such as current, speed, and load. It then retrieves pre-stored historical operating data for all similar steering motors. It then calculates the similarity between the current operating conditions of the steering motor and the historical operating conditions of each data point in the historical operating data. The normal operating duration in the target historical operating data with the highest similarity is selected as the second normal operating duration.

[0134] Finally, the shorter of the first normal operation duration and the second normal operation duration is selected as the normal operation duration of the steering motor when the normal phase operates at a current corresponding to the target wheel steering angle.

[0135] S320: Calculate the probability of successful steering of the target vehicle when the steering motor is out of phase based on the target force, the steering time, and the normal operation time.

[0136] Specifically, the driver's image information of the target vehicle is obtained through the in-vehicle image acquisition device. The driver's image is analyzed using image recognition technology to identify the driver's facial features, age, gender, and other information. This information is then compared with a pre-stored driver information database to confirm the driver's identity and obtain relevant driving data, such as historical driving habits and driving experience.

[0137] Based on the acquired driving data, the system uses a pre-set driving proficiency assessment model to determine the driver's driving proficiency level. This assessment model comprehensively considers factors such as length of driving experience, consistent driving habits, and the ability to respond to emergencies. It categorizes driving proficiency into different levels, such as beginner, intermediate, and advanced, and assigns a corresponding proficiency score to each level. Simultaneously, based on the driver's relevant data, the system searches the system's built-in database for a normal force range that matches the driver's age, gender, and other characteristics.

[0138] Next, the maximum force in the calculated target force is compared with the normal force range found. If the target force is within the normal force range, it indicates that the force required by the driver for the current steering operation meets the normal requirements based on their age, gender, and other characteristics. Based on the first difference between the target force and the minimum value in the normal force range, the preset force score corresponding to the first difference in the first scoring table is obtained. If the target force is outside the normal force range, based on the second difference between the target force and the maximum value in the normal force range, the preset force score corresponding to the second difference in the second scoring table is obtained.

[0139] Then, the sum of all turn times is calculated to obtain the total turn time. If the total turn time is greater than the normal operating time, the turn time score is determined to be the preset minimum score. If the total turn time is less than or equal to the normal operating time, the difference between the total turn time and the normal operating time is calculated, and the turn time score corresponding to the difference is obtained from the preset score table.

[0140] Finally, a weighted calculation is performed based on the influence weights of the predetermined factors on the steering success probability, the proficiency score, the force score, and the steering duration score. The probability of the target vehicle successfully steering in the event of a steering motor phase loss is calculated. The larger the probability, the more likely the steering is to succeed.

[0141] S321. When the turning probability is less than a preset threshold, the driver of the target vehicle is prompted to drive straight or stop through the vehicle display or speaker.

[0142] When the steering probability falls below a preset threshold, a pre-set warning command is sent to the vehicle's display or speaker. Upon receiving the command, the display displays a warning message reminding the driver to drive straight or stop. Upon receiving the command, the speaker plays a warning message reminding the driver to drive straight or stop.

[0143] S322: When it is detected that the target vehicle is still moving within a preset time period and the steering motor has a two-phase or three-phase fault, a straight route of the target vehicle is determined according to the current position of the target vehicle.

[0144] Specifically, when it is detected that the target vehicle is still moving within a preset time, it is determined whether the steering motor has a two-phase or three-phase fault. When the cumulative ratio of three phase currents exceeds their corresponding ratio thresholds, it is determined that the steering motor has a two-phase or three-phase fault.

[0145] If the target vehicle continues to travel for a preset period of time and the steering motor experiences a two-phase or three-phase fault, the target vehicle's straight-ahead route is determined based on the target vehicle's current position. Based on the target vehicle's lane, a search is performed in the map database along the linear extension of the lane to find the end of the lane or a restricted location (such as the end of the road, where further travel is prohibited). This location is determined as the farthest point the target vehicle can reach by traveling straight along the current lane. If the search encounters an intersection or other location where continued travel is permitted but with a specified travel direction, a determination is made based on traffic regulations and map data to determine whether straight-ahead travel is permitted at the intersection. If so, the search continues along the linear extension of the lane. If not, the intersection is determined as the farthest point.

[0146] In some embodiments, the impact of factors such as the vehicle's speed and remaining range on the vehicle's straight-line travel may also be considered. The vehicle's remaining range is first obtained. If the vehicle's remaining range is insufficient to support travel to the farthest position displayed in the map database, the vehicle's maximum traversable distance is calculated based on the remaining range and current speed. The farthest position within this range is then determined as the endpoint of the target vehicle's straight-line route (i.e., the farthest position).

[0147] Finally, according to the current position and the farthest position of the target vehicle, a straight driving route from the current position to the farthest position is generated, that is, the straight route of the target vehicle.

[0148] S323: When there is a target area in the straight route, the driver of the target vehicle is prompted to drive along the straight route to the target area and park via the vehicle-mounted display screen or speaker.

[0149] Specifically, the system first retrieves information about each section of the straight route from a map database, including its location, traffic volume, and surrounding environment. It then compares this information with pre-defined target area characteristics to calculate the similarity between each section and the target area. The target area is typically an area with low traffic volume or is relatively remote.

[0150] When the similarity exceeds a preset threshold (i.e., the target area exists within the straight route), a control command is generated based on the straight route and sent to the vehicle's display or speaker. Upon receiving the command, the display displays the straight route, reminding the driver to drive straight along the straight route to the target area and park. Upon receiving the command, the speaker plays a prompt message, reminding the driver that the vehicle's steering is seriously faulty and that if parking is unavailable, the driver should drive straight along the straight route to the target area and park.

[0151] S324. Obtain the real-time location of the target vehicle.

[0152] Get the real-time location collected by the built-in positioning module of the target vehicle.

[0153] S325. When the target vehicle turns at a traffic light intersection and the distance between the real-time position and the stop line of the traffic light intersection is within a preset distance range, all traffic lights at the traffic light intersection are controlled to be red.

[0154] Specifically, the stop line position of the traffic light intersection ahead of the vehicle is first obtained from a map database. Then, a first distance between the real-time position of the target vehicle and the stop line position is calculated using a distance calculation formula.

[0155] When the first distance is within a preset first distance range (i.e., the vehicle cannot change lanes before reaching the stop line), the vehicle's turn signal status and the driving direction of the lane in which the vehicle is located are obtained. If the driving direction only includes turning, the target vehicle is determined to be turning at the traffic light intersection. If the driving direction includes turning and straight driving, and the turn signal status is on, the target vehicle is determined to be turning at the traffic light intersection.

[0156] When the target vehicle turns at a traffic light, the distance calculation formula continues to calculate the real-time distance between the target vehicle's position and the stop line. When the real-time distance is within the preset distance range (i.e., the distance between the vehicle and the stop line is approximately one vehicle length), a control command is sent to the traffic signal control system. Upon receiving the command, the traffic signal control system sets all traffic lights at the intersection to red. Simultaneously, a command is sent to the on-board display or speaker to remind the target vehicle to stop before the stop line.

[0157] S326. When it is detected that there is no vehicle at the traffic light intersection, the traffic light at the traffic light intersection corresponding to the driving direction of the target vehicle is controlled to be green.

[0158] Specifically, a traffic image of the traffic light intersection is first acquired by an image acquisition module built into the vehicle, or a communication connection is established with a traffic monitoring system to acquire the traffic image of the traffic light intersection.

[0159] Next, an image recognition algorithm is used to identify the presence of vehicles in the traffic image. Deep learning-based object detection algorithms, such as Faster R-CNN, are used to identify the presence of vehicles in the image. These algorithms, trained on a large number of traffic scene images, are able to accurately identify vehicles in the image. The system inputs the preprocessed traffic image into the trained object detection algorithm, which outputs the location and category information of all detected vehicles in the image. Based on these outputs, the system determines whether a vehicle exists in the image. If the number of detected vehicles is zero, the intersection is considered to be empty.

[0160] When the system detects that there are no vehicles at a traffic light intersection, it sends a control command to the traffic signal control system. Upon receiving the command, the traffic signal control system sets the traffic light for the target vehicle's lane at the intersection to green. Simultaneously, it sends a command to the vehicle's onboard display or speaker to remind the target vehicle to continue driving.

[0161] In the embodiment of the present application, by calculating the probability of successful steering, the safety of vehicle steering when the steering motor is out of phase can be accurately assessed. When the steering probability is lower than a preset threshold, the driver is promptly prompted to drive straight or stop through the on-board display or speaker. This can avoid traffic accidents caused by steering failure due to the out of phase of the steering motor, ensure the safety of the driver and the vehicle, and improve the driving safety and controllability of the vehicle in a fault state. At the same time, when it is detected that there are no vehicles at the traffic light intersection where the vehicle is turning, only the traffic light at the traffic light intersection that is in the same direction as the vehicle's travel direction is controlled to turn green, allowing the vehicle and other vehicles behind the vehicle that are in the same direction of travel to continue turning, avoiding the risk of the vehicle losing control when turning at the intersection due to the motor phase failure, and colliding with vehicles traveling normally in other directions, thereby reducing the probability of traffic accidents caused by vehicles with phase failure when passing through the intersection.

[0162] The above describes the method for detecting phase loss of a permanent magnet synchronous motor in the embodiment of the present application. The following describes in detail the vehicle control system in the embodiment of the present application in combination with the above-mentioned method for detecting phase loss of a permanent magnet synchronous motor.

[0163] See also Figure 4 , is a schematic diagram of an exemplary hardware structure of a vehicle control system in an embodiment of the present application.

[0164] In some embodiments, the vehicle control system 400 includes a computer device, which may be a terminal device. The computer device includes a processor 401, memory 402, a sensor module 403, a communication module 404, an input device 405, and an output device 406, all connected via a system bus. The processor 401 of the computer device provides computing and control capabilities. The memory 402 of the computer device includes a non-volatile storage medium and internal memory. The non-volatile storage medium stores an operating system, computer programs, and a database. The internal memory provides an environment for the operating system and computer programs stored in the non-volatile storage medium. The database is used to store data. The sensor module 403 of the computer device collects real-time three-phase current from the steering motor. The communication module 404 of the computer device transmits the collected real-time three-phase current and image data to the vehicle controller and transmits control instructions to the vehicle display screen and speakers. The input device 405 of the computer device receives the collected real-time three-phase current and image data. The output device 406 of the computer device displays warning information, driving routes, and other information. When the computer program is executed by the processor 401, the method for detecting phase loss of a permanent magnet synchronous motor in the embodiment of the present application is implemented.

[0165] Those skilled in the art will understand that Figure 4 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than shown in the figure, or combine certain components, or have a different component arrangement.

[0166] In some embodiments of the present application, a computer-readable storage medium is provided, comprising instructions. When the instructions are executed on the vehicle control system 400, the vehicle control system 400 can execute the permanent magnet synchronous motor phase loss detection method in the embodiment of the present application.

[0167] In some embodiments of the present application, a computer program product is also provided. When the computer program product runs on the vehicle control system 400, the vehicle control system 400 executes the permanent magnet synchronous motor phase loss detection method in the embodiment of the present application.

[0168] As described above, the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

[0169] As used in the above embodiments, the term “when…” may be interpreted to mean “if…” or “after…” or “in response to determining…” or “in response to detecting…”, depending on the context. Similarly, the phrases “upon determining…” or “if (stated condition or event) is detected” may be interpreted to mean “if determining…” or “in response to determining…” or “upon detecting (stated condition or event)” or “in response to detecting (stated condition or event)”, depending on the context.

[0170] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from one website, computer, server or data center to another website, computer, server or data center via a wired (e.g., coaxial cable, optical fiber, digital subscriber line) or wireless (e.g., infrared, wireless, microwave, etc.) method. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more available media integrations. The available medium can be a magnetic medium (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid-state hard disk).

[0171] Those skilled in the art will appreciate that all or part of the process steps in the above-described method embodiments can be implemented by a computer program instructing the relevant hardware. The program can be stored in a computer-readable storage medium, and when executed, the program can include the process steps in the above-described method embodiments. The aforementioned storage medium includes various media capable of storing program code, such as ROM or random access memory (RAM), magnetic disks, or optical disks.

Claims

1. A method for detecting a phase loss fault of a permanent magnet synchronous motor, characterized in that: include: Acquire the real-time three-phase current and real-time load status of the steering motor, wherein the real-time three-phase current includes the A-phase current, the B-phase current, and the C-phase current; The absolute value of the real-time three-phase current is multiplied by a preset coefficient corresponding to the real-time load state to obtain a target three-phase current; the target three-phase currents are respectively accumulated and calculated to obtain a three-phase current cumulative sum, wherein the accumulation calculation is to accumulate and calculate the target current of phase A, the target current of phase B, and the target current of phase C obtained at different time points, respectively, to obtain the cumulative sum of the current of phase A, the cumulative sum of the current of phase B, and the cumulative sum of the current of phase C; When any current cumulative sum among the three-phase current cumulative sums exceeds a preset cumulative sum threshold, or when the steering wheel steering angle of the target vehicle corresponding to the steering motor changes, resetting the three-phase current cumulative sum to a preset three-phase current cumulative sum; Selecting the current cumulative sums of any two phases from the A-phase current cumulative sum, the B-phase current cumulative sum, and the C-phase current cumulative sum, and dividing the relatively larger current cumulative sum by the relatively smaller current cumulative sum to obtain a cumulative ratio set, the cumulative ratio set including the cumulative ratios between phase A and phase B, phase A and phase C, and phase B and phase C; Obtaining a ratio threshold corresponding to each cumulative ratio value in the cumulative ratio value set; determining whether the accumulated ratio exceeds the ratio threshold; If so, increase the number of phase loss times by one; If not, set the number of phase loss times to zero; When the number of phase failures exceeds a preset number threshold corresponding to the real-time load state, an early warning strategy is executed.

2. The method according to claim 1, characterized in that The obtaining of the ratio threshold corresponding to each accumulated ratio in the accumulated ratio set specifically includes: Determining a preset three-phase current based on a current steering wheel steering angle, a current speed of the target vehicle, and a current wheel steering angle, wherein the preset three-phase current is the three-phase current required by the steering motor to cause the wheels to steer according to a steering angle corresponding to the steering wheel steering angle; Substituting the preset three-phase current, the current vehicle speed, the preset wheel steering angle corresponding to the current steering wheel steering angle, and the current wheel steering angle into a ratio threshold calculation formula to obtain a ratio threshold corresponding to each cumulative ratio in the cumulative ratio set; The ratio threshold calculation formula is: in, is the ratio threshold corresponding to the cumulative ratio obtained by dividing the X-phase current cumulative sum by the Y-phase current cumulative sum, η1 is the current loss rate of the current transmitted from the battery to the X-phase in the steering motor, η2 is the current loss rate of the current transmitted from the battery to the Y-phase in the steering motor, t is the number of accumulations of the cumulative sum, I X,set (τ) is the preset current of phase X when the cumulative number of times is τ, I Y,set (τ) is the preset current of the Y phase when the cumulative number of times is τ, γ1 is the high-frequency noise gain coefficient of the X phase, γ2 is the high-frequency noise gain coefficient of the Y phase, λ is the steering compensation gain coefficient, θ is the preset wheel steering angle corresponding to the current steering wheel steering angle, θ actual is the current wheel steering angle, θ max is the maximum allowable steering angle deviation, α is the vehicle speed adjustment reference value, β is the vehicle speed adjustment sensitivity coefficient, v is the current vehicle speed, and v0 is the vehicle speed threshold.

3. The method according to claim 2, characterized in that After the step of increasing the number of phase failures by one, the method further includes: Inputting the real-time three-phase current into a simulation model to simulate a first wheel steering angle of the target vehicle, and inputting the preset three-phase current into the simulation model to obtain a second wheel steering angle, wherein the simulation model is trained based on three-phase current data obtained from multiple tests of the target vehicle under different operating conditions and corresponding actual wheel steering angle annotations; When a first similarity between the actual wheel steering angle of the target vehicle and the first wheel steering angle is less than a preset first threshold, calculating a second similarity between the actual wheel steering angle and the second wheel steering angle; When the second similarity is greater than a preset second threshold, the number of phase loss times is set to zero.

4. The method according to claim 1, wherein After the step of executing the early warning strategy when the number of phase failures exceeds a preset number threshold corresponding to the real-time load state, the method further includes: When it is detected that the target vehicle is still moving within a preset time period and the steering motor has a single-phase fault, obtaining the driving direction of the lane where the target vehicle is located; When the driving direction includes turning, determining a probability of the target vehicle successfully turning in the event of a steering motor phase loss according to a fault condition of the steering motor; When the turning probability is less than a preset threshold, the driver of the target vehicle is prompted to drive straight or stop through an on-board display screen or a speaker.

5. The method according to claim 4, characterized in that When the driving direction includes turning, determining the probability of the target vehicle successfully turning when the steering motor is out of phase according to the fault condition of the steering motor specifically includes: When the driving direction includes turning, obtaining a target wheel steering angle required for the target vehicle to perform a steering operation and a turning duration corresponding to the target wheel steering angle; determining, based on a fault condition of the steering motor, a target force for a driver of the target vehicle to turn the steering wheel to a target steering wheel steering angle corresponding to the target wheel steering angle; determining, according to a fault condition of the steering motor, a normal operating time duration of a normal phase of the steering motor operating at a current corresponding to the target wheel steering angle; The steering probability of the target vehicle successfully steering when the steering motor is out of phase is calculated according to the target force, the steering duration, and the normal operation duration.

6. The method according to claim 1, characterized in that After the step of executing the early warning strategy when the number of phase failures exceeds a preset number threshold corresponding to the real-time load state, the method further includes: When it is detected that the target vehicle is still moving within a preset time period and the steering motor has a two-phase or three-phase fault, a straight route of the target vehicle is determined according to the current position of the target vehicle; When there is a target area in the straight route, the driver of the target vehicle is prompted to drive to the target area along the straight route and park through the vehicle-mounted display screen or speaker.

7. The method according to claim 1, characterized in that After the step of executing the early warning strategy when the number of phase failures exceeds a preset number threshold corresponding to the real-time load state, the method further includes: Obtaining the real-time position of the target vehicle; When the target vehicle turns at the traffic light intersection and the distance between the real-time position and the stop line of the traffic light intersection is within a preset distance range, controlling all traffic lights at the traffic light intersection to be red; When it is detected that there is no vehicle at the traffic light intersection, the traffic light at the traffic light intersection corresponding to the driving direction of the target vehicle is controlled to be green.

8. A vehicle control system, characterized in that: include: one or more processors and memory; The memory is coupled to the one or more processors, and is configured to store computer program codes, where the computer program codes include computer instructions. The one or more processors call the computer instructions to enable the vehicle control system to execute the method according to any one of claims 1 to 7.

9. A computer-readable storage medium storing computer instructions, characterized in that: When the computer instructions are executed on a vehicle control system, the vehicle control system is caused to execute the method according to any one of claims 1 to 7.

10. A computer program product, characterized in that When the computer program product is run on a vehicle control system, the vehicle control system is caused to execute the method according to any one of claims 1 to 7.

Images