Open-circuit fault detection method, device, domain controller, system and vehicle

Abstract

The invention relates to an open-circuit fault detection method and device, a domain controller, a system and a vehicle, and relates to the technical field of open-circuit fault detection. According to the method, the three-phase current data of the cooling water pump can be firstly obtained, and under the condition that at least one phase of current data in the three-phase current data meets the pre-judged open circuit condition, at least one of the following motor parameters including the three-phase current unbalance degree, rotor data and water pump vibration data is monitored. If it is monitored that any motor parameter in the three-phase current unbalance degree, the rotor data and the water pump vibration data is abnormal, it is determined that the current data meeting the pre-judgment open-circuit condition occurs, and an open-circuit fault occurs to the target phase corresponding to the current data meeting the pre-judgment open-circuit condition. Therefore, under the condition that the suspected open circuit of the corresponding phase is predicted according to the single-phase current, prediction can be performed by fusing at least one motor parameter of the cooling water pump, so that the misjudgment rate of the open-circuit fault of the cooling water pump can be reduced and the open-circuit phase positioning precision can be improved through multi-data cooperative detection.

Description

Technical Field

[0001] This invention relates to the field of open circuit fault detection technology, and specifically to an open circuit fault detection method, device, domain controller, system, and vehicle. Background Technology

[0002] The direct-drive cooling water pump is a core component of the vehicle's thermal management system. It mainly uses the motor to directly drive the impeller to rotate, forcibly circulating the cooling medium to cool high-heat components in the vehicle, such as the drive motor, electronic control system, and power battery, thereby achieving temperature control of these high-heat components.

[0003] Direct-drive water pumps typically use three-phase brushless DC motors. If any phase in the three-phase output circuit from the motor controller to the motor experiences an open-circuit fault, it will significantly reduce the operational stability of the thermal management system. Currently, the common method for diagnosing open-circuit faults is by detecting the bus current of the three-phase water pump, which makes it impossible to accurately pinpoint the phase of the open-circuit fault. Summary of the Invention

[0004] One objective of this invention is to provide an open-circuit fault detection method to solve the problem that the common method of detecting the bus current of a three-phase water pump for open-circuit fault diagnosis cannot accurately locate the phase of the open-circuit fault; a second objective is to provide an open-circuit fault detection device; a third objective is to provide a domain controller; a fourth objective is to provide a thermal management system; and a fifth objective is to provide a vehicle.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] An open-circuit fault detection method includes: acquiring three-phase current data of a cooling water pump; monitoring at least one of the following motor parameters when at least one phase current data in the three-phase current data meets the predicted open-circuit condition: three-phase current imbalance, rotor data, and water pump vibration data; if any one of the motor parameters in the three-phase current imbalance, rotor data, and water pump vibration data is detected to be abnormal, determining the current data that meets the predicted open-circuit condition, and the corresponding target phase experiencing an open-circuit fault.

[0007] Based on the above technical means, when predicting a suspected open circuit in a corresponding phase based on single-phase current, at least one motor parameter of the cooling water pump can be integrated for prediction. This allows for multi-data collaborative detection, reducing the misjudgment rate of open circuit faults in the cooling water pump and improving the accuracy of open circuit phase location.

[0008] In one optional embodiment, when the cooling water pump is in operation, monitoring rotor data includes: acquiring a Hall waveform and determining the rotor speed or speed fluctuation rate of the cooling water pump based on the Hall waveform; the method further includes: determining that the rotor data is abnormal when the rotor speed of the cooling water pump is lower than a set rotor speed under normal operation, or when the speed fluctuation rate of the cooling water pump exceeds a set fluctuation rate under normal operation; or, acquiring an estimated difference in rotor position angle or speed fluctuation rate; the method further includes: determining that the rotor data is abnormal when the estimated difference in rotor position angle exceeds a set angle difference under normal operation, or when the speed fluctuation rate of the cooling water pump exceeds a set fluctuation rate under normal operation.

[0009] Based on the aforementioned technical means, the cooling water pump in operation can detect abnormal operating conditions such as a decrease in output speed or even shutdown by using rotor data, including but not limited to Hall waveforms, speed fluctuation rate, or rotor position angle estimation difference. This allows for further prediction of whether a three-phase open-circuit fault has occurred in the cooling water pump, by combining single-phase current abnormalities with data on open-circuit faults, thus reducing the false positive rate of open-circuit faults.

[0010] In one optional aspect of the invention, when the cooling water pump is in the start-up phase, the monitoring of rotor data includes:

[0011] The method further includes obtaining the rotor position and rotor speed;

[0012] If the rotor position is not reset to the set rotor position, the rotor data is determined to be abnormal;

[0013] If the rotor position is reset to the set rotor position, and the rotor speed does not reach the expected speed value within a preset time period, the rotor data is determined to be abnormal.

[0014] Based on the aforementioned technical means, during the startup phase, the cooling water pump uses rotor data, including but not limited to rotor position and rotor speed, to detect whether the pump experiences abnormal operating conditions such as output pre-positioning failure or open-loop acceleration timeout. This allows for further prediction of whether a three-phase open-circuit fault has occurred in the cooling water pump, by combining this with single-phase current abnormality data, thus reducing the false positive rate of open-circuit faults.

[0015] In one optional embodiment, the method further includes: determining that the water pump vibration data is abnormal when the water pump vibration data exceeds a set vibration amplitude during normal operation.

[0016] Based on the aforementioned technical means, the vibration data of the cooling water pump is used to determine whether abnormal operating conditions such as abnormal vibration occur. This allows for further prediction of whether an open-circuit fault has occurred in the three phases of the cooling water pump, by combining the single-phase current abnormality data with the prediction of open-circuit faults, thus reducing the false positive rate of open-circuit faults.

[0017] An optional embodiment of the invention, wherein monitoring three-phase current imbalance includes: selecting the maximum and minimum current values ​​of the three-phase current data within a single acquisition cycle, and calculating the average value of the three-phase current data within the single acquisition cycle; calculating the three-phase current imbalance based on the maximum current value, the minimum current value, and the average value of the three-phase current; the method further includes: determining that an abnormality in the three-phase current imbalance is detected when the three-phase current imbalance continuously meets the current abnormality condition.

[0018] Based on the above technical means, after obtaining the current data of each phase, the current difference between each phase current data can be calculated to determine whether the balance state of the three-phase current of the cooling water pump has been broken. This can further predict whether the three phases of the cooling water pump have an open circuit fault and reduce the false alarm rate of open circuit fault.

[0019] In one optional embodiment of the invention, the method further includes: performing an application-layer restart, and after each application-layer restart step, re-acquiring the three-phase current data of the cooling water pump, and combining the three-phase current data with at least one of the motor parameters to determine whether there is a target phase with an open-circuit fault; if the restart threshold reaches a set safety threshold and there is still a target phase with an open-circuit fault, matching the open-circuit fault information associated with the target with the open-circuit fault, and uploading it to the application layer.

[0020] Based on the aforementioned technical methods, application-layer restarts can eliminate the need to initialize underlying hardware and start all drivers, while retaining fault logs, thus improving the efficiency of fault recovery. If an open-circuit fault persists in a target phase after multiple restarts, it can be ruled out that the open-circuit fault is caused by the software program. The corresponding open-circuit fault information is then uploaded to the application layer, preserving this information for accurate location of the faulty target phase and facilitating rapid repair.

[0021] A three-phase open-circuit fault detection device includes: a current data acquisition module for acquiring three-phase current data of a cooling water pump; a motor parameter monitoring module for monitoring at least one of the following motor parameters when at least one phase current data in the three-phase current data meets the predicted open-circuit condition: three-phase current imbalance, rotor data, and water pump vibration data; and a fault determination module for determining the current data that meets the predicted open-circuit condition and identifying the corresponding target phase as having an open-circuit fault if any one of the motor parameters (three-phase current imbalance, rotor data, and water pump vibration data) is detected to be abnormal.

[0022] A domain controller configured to perform the open-circuit fault detection method described in any of the preceding inventions.

[0023] A thermal management system includes a three-phase open-circuit fault detection device as described above and a domain controller as described above.

[0024] A vehicle comprising a thermal management system as described above.

[0025] The beneficial effects of this invention are:

[0026] In cases where a single-phase current is used to predict a suspected open circuit in the corresponding phase, at least one motor parameter of the cooling water pump is integrated for prediction. This allows for collaborative detection using multiple data sources, thereby reducing the false positive rate of open circuit faults in the cooling water pump and improving the accuracy of open circuit phase location. Attached Figure Description

[0027] Figure 1 This is a flowchart illustrating the steps of an open-circuit fault detection method provided in an embodiment of the present invention;

[0028] Figure 2 This is a flowchart illustrating the steps of another open-circuit fault detection method provided in an embodiment of the present invention.

[0029] Figure 3 A flowchart illustrating the steps of another open-circuit fault detection method provided in an embodiment of the present invention;

[0030] Figure 4 This is a schematic block diagram of an open-circuit fault detection device provided in an embodiment of the present invention. Detailed Implementation

[0031] The embodiments of the present invention will be described below with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are only for illustrating the present invention and not for limiting the scope of protection of the present invention.

[0032] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0033] The direct-drive cooling water pump is a core component of the vehicle's thermal management system. It mainly uses the motor to directly drive the impeller to rotate, forcibly circulating the cooling medium to cool high-heat components in the vehicle, such as the drive motor, electronic control system, and power battery, thereby achieving temperature control of these high-heat components.

[0034] Direct-drive water pumps typically use three-phase brushless DC motors. If any phase in the three-phase output circuit from the motor controller to the motor experiences an open-circuit fault, it will significantly reduce the operational stability of the thermal management system. Currently, the common method for diagnosing open-circuit faults is by detecting the bus current of the three-phase water pump, which makes it impossible to accurately pinpoint the phase of the open-circuit fault.

[0035] To address the aforementioned technical problems, this invention proposes an embodiment. This embodiment first acquires the three-phase current data of the cooling water pump. If at least one phase of the three-phase current data meets the predicted open-circuit condition, it monitors at least one of the following motor parameters: three-phase current imbalance, rotor data, and pump vibration data. If any of these motor parameters is detected to be abnormal, the current data that meets the predicted open-circuit condition is determined, and the corresponding target phase experiences an open-circuit fault. Therefore, when predicting a suspected open circuit based on single-phase current, at least one cooling water pump motor parameter can be fused for prediction. This allows for multi-data collaborative detection, reducing the false positive rate of open-circuit faults in the cooling water pump and improving the accuracy of open-circuit phase location.

[0036] Reference Figure 1 As shown, this embodiment of the invention provides an open-circuit fault detection method, which may include:

[0037] S101. Obtain the three-phase current data of the cooling water pump.

[0038] In this embodiment of the invention, the cooling water pump is driven by a three-phase brushless DC motor. Sampling resistors can be connected in series on each of the three-phase output lines of the motor, and the voltage signals across these resistors are amplified by a current sampling chip (e.g., Drv3245). The domain controller can determine the single-phase current data corresponding to the cooling water pump based on the resistance value of the sampling resistors and the gain of the current sampling chip, thereby synthesizing the three-phase current data. For example, the three-phase current data can be the V-phase current Iv, the U-phase current Iu, and the W-phase current Iw.

[0039] S102. If at least one phase current data in the three-phase current data meets the predicted open circuit condition, monitor at least one of the following motor parameters: three-phase current imbalance, rotor data, and water pump vibration data.

[0040] In this embodiment of the invention, if any phase of the cooling water pump is open-circuited, the corresponding single-phase current data will be very small or close to zero. Therefore, a condition for determining the presence of an open-circuit fault in the corresponding phase can be preset based on the current data, and this can be used as a pre-judgment condition for open-circuit detection. In one example, the pre-judgment condition for open-circuit detection includes at least: the unidirectional current data is less than or equal to the open-circuit current threshold. For example, if the current data of any one phase in the three-phase current data is less than or equal to the corresponding associated open-circuit current threshold, the phase corresponding to the single-phase current data being less than or equal to the open-circuit current threshold is determined to be possibly open-circuited. The open-circuit current threshold can be a current value obtained by those skilled in the art through experiments under the condition of an open circuit in the corresponding phase, and is not limited in detail here. Furthermore, the open-circuit current thresholds for the three phases can be consistent or differ from each other.

[0041] Since even when single-phase current data meets the predicted open-circuit condition, there may still be current changes corresponding to other operating conditions that meet the non-open-circuit condition. To reduce the false positive rate of open-circuit faults, other motor parameters that change due to the open-circuit condition can be monitored. In one example, the domain controller can monitor at least one of the following motor parameters: three-phase current imbalance, rotor data, and pump vibration data.

[0042] The three-phase current imbalance can be used to assess whether the three-phase current is in a balanced state. When the cooling water pump's three-phase current is under normal operating conditions, the cumulative sum of the three-phase current data is zero, and the amplitude of each phase current is equal, resulting in a very small three-phase current imbalance. When one phase of the three-phase current is open-circuited, the currents of the other two phases will increase. This disrupts the balance of the three-phase current, leading to a significant increase in the three-phase current imbalance.

[0043] The rotor data may include, but is not limited to, rotor position and rotor speed. When the cooling water pump operates in an open-circuit condition, it can lead to a decrease in the pump's output speed or even stoppage, as well as abnormal vibration, and disrupt the balance of the three-phase current data. Therefore, the rotor data can be used to detect whether the cooling water pump is experiencing abnormal operating conditions such as a decrease in output speed or even stoppage; the pump vibration data can be used to determine whether the cooling water pump is experiencing abnormal vibration; and the three-phase current imbalance can be used to determine whether the three-phase current of the cooling water pump is in an unbalanced state.

[0044] S103. If any motor parameter among the three-phase current imbalance, rotor data, and water pump vibration data is found to be abnormal, the current data that meets the predicted open circuit condition is determined, and the corresponding target phase has an open circuit fault.

[0045] In this embodiment of the invention, if any one of the motor parameters—the three-phase current imbalance, rotor data, and water pump vibration data—is detected to be abnormal, the current data that meets the predicted open-circuit condition is determined using a fault detection strategy that requires at least two parameters to be in abnormal operating conditions. The corresponding target phase then experiences an open-circuit fault. For example, if only the V-phase current Iv meets the predicted open-circuit condition and an abnormality is detected in the three-phase current imbalance, the V-phase of the cooling water pump is determined to have an open-circuit fault. As another example, if only the V-phase current Iv meets the predicted open-circuit condition and no abnormalities are detected in the three-phase current imbalance, rotor data, and water pump vibration data, the cooling water pump is determined not to have an open-circuit fault. Yet another example, if both the V-phase current Iv and the W-phase current Iw meet the predicted open-circuit condition and an abnormality is detected in the three-phase current imbalance, both the V-phase and W-phase of the cooling water pump are determined to have open-circuit faults.

[0046] In summary, when a single-phase current is used to predict a suspected open circuit in a corresponding phase, at least one motor parameter of the cooling water pump is integrated for prediction. This allows for collaborative detection of multiple data sources, eliminating the probability of other operating conditions besides the single parameter abnormality matching the open circuit condition. This reduces the misjudgment rate of the open circuit fault of the cooling water pump and improves the accuracy of open circuit phase location.

[0047] Reference Figure 2 As shown in the figure, this embodiment of the invention also provides another method for detecting open circuit faults, the method may include:

[0048] S201. Obtain the three-phase current data of the cooling water pump.

[0049] In this embodiment of the invention, the cooling water pump is driven by a three-phase brushless DC motor. Sampling resistors can be connected in series on each of the three-phase output lines of the motor, and the voltage signals across these resistors are amplified by a current sampling chip (e.g., Drv3245). The domain controller can determine the single-phase current data corresponding to the cooling water pump based on the resistance value of the sampling resistors and the gain of the current sampling chip, thereby synthesizing the three-phase current data. For example, the three-phase current data can be the V-phase current Iv, the U-phase current Iu, and the W-phase current Iw.

[0050] S202. If at least one phase current data in the three-phase current data meets the predicted open circuit condition, monitor one of the following motor parameters: three-phase current imbalance, rotor data, and water pump vibration data.

[0051] In this embodiment of the invention, since even when single-phase current data meets the predicted open-circuit condition, there may also be current changes corresponding to other operating conditions that meet the non-open-circuit condition, in order to reduce the false alarm rate of open-circuit faults, other motor parameters that change due to the open-circuit condition can be further monitored. In one example, the domain controller can monitor at least one of the following motor parameters: three-phase current imbalance, rotor data, and pump vibration data.

[0052] The three-phase current imbalance can be used to assess whether the three-phase current is in a balanced state. When the cooling water pump's three-phase current is under normal operating conditions, the cumulative sum of the three-phase current data is zero, and the amplitude of each phase current is equal, resulting in a very small three-phase current imbalance. When one phase of the three-phase current is open-circuited, the currents of the other two phases will increase. This disrupts the balance of the three-phase current, leading to a significant increase in the three-phase current imbalance.

[0053] In one or more embodiments, if at least one phase current data in the three-phase current data satisfies the predicted open-circuit condition, the three-phase current imbalance can be calculated based on the three-phase current data. For example, firstly, the maximum and minimum current values ​​of the three-phase current data within a single acquisition cycle are selected, and the average value of the three-phase current data within a single acquisition cycle is calculated. Then, based on the maximum current value, the minimum current value, and the average value of the three-phase current, the three-phase current imbalance is calculated.

[0054] A single acquisition cycle can be determined based on the acquisition interface configuration parameters of the acquisition chip. For example, if the single acquisition cycle is 50 microseconds, the current needs to be acquired at least once per acquisition cycle. For instance, if two acquisitions are performed, one acquisition is performed every 25 micrometers. Correspondingly, the U-phase currents within a single acquisition cycle are Iu1 and Iu2, the V-phase currents within a single acquisition cycle are Iv1 and Iv2, and the W-phase currents within a single acquisition cycle are Iw1 and Iw2. The formula for calculating the three-phase current imbalance is as follows:

[0055]

[0056] In the above formula (1), δ refers to the three-phase current imbalance; max(|Iu|,|Iv|,|Iw|) refers to the largest value among all absolute values ​​of the three-phase current data detected in a single cycle, and is used as the maximum value of the current; min(|Iu|,|Iv|,|Iw|) refers to the smallest value among all absolute values ​​of the three-phase current data detected in a single cycle, and is used as the minimum value of the current.

[0057] avg(|Iu|, |Iv|, |Iw|) refers to the average of the absolute values ​​of all three-phase currents detected within a single cycle, and is used as the average value of the three-phase currents. For example, when three-phase current data is detected twice within a single cycle, the maximum current value corresponds to the largest absolute value among currents Iu1, Iu2, Iv1, Iv2, Iw1, and Iw2. The minimum current value corresponds to the smallest absolute value among currents Iu1, Iu2, Iv1, Iv2, Iw1, and Iw2. The average value of the three-phase current corresponds to the value obtained by averaging the absolute values ​​of currents Iu1, Iu2, Iv1, Iv2, Iw1, and Iw2.

[0058] When the three-phase current imbalance continuously meets the current anomaly condition, an anomaly in the three-phase current imbalance is determined to be detected. The current anomaly condition can be determined based on the change in the three-phase current imbalance when the three-phase current of the cooling water pump is in balance (also known as normal operating condition). For example, the current anomaly condition includes at least: the three-phase current imbalance is greater than a preset imbalance threshold. The preset imbalance threshold can be a value approaching zero. Those skilled in the art can determine the preset imbalance threshold based on the upper limit of the change in three-phase current imbalance under normal operating conditions in actual testing. When the calculated three-phase current imbalance meets the current anomaly condition, it is determined that the current change in the three-phase current does not belong to the normal operating condition, thereby determining that the three-phase current imbalance is abnormal.

[0059] In one or more embodiments, the water pump vibration data can be monitored when at least one phase of the three-phase current data meets the predicted open-circuit condition. When the cooling water pump operates under open-circuit conditions, it can cause abnormal vibrations. Therefore, when a vibration sensor is embedded in the cooling water pump, the domain controller can acquire the pump vibration amplitude collected by the sensor. If the pump vibration data exceeds (or is understood as greater than) a set vibration amplitude during normal operation, the pump vibration data is determined to be abnormal. The set vibration amplitude can be determined by those skilled in the art based on the upper limit of the pump vibration amplitude variation collected by the vibration sensor under normal operating conditions.

[0060] In one or more embodiments, when at least one phase current data in the three-phase current data meets the predicted open-circuit condition, the rotor data of the cooling water pump can be monitored. The rotor data may include, but is not limited to, rotor position and rotor speed. When the cooling water pump operates under open-circuit conditions, it can cause a decrease in the pump's output speed or even stoppage. Therefore, the rotor data can be used to detect whether the cooling water pump is experiencing abnormal operating conditions such as a decrease in output speed or even stoppage, and combining this with abnormal current conditions can reduce the false alarm rate for open-circuit faults.

[0061] In one example, the domain controller can also acquire Hall waveforms and determine the rotor speed or speed fluctuation rate of the cooling water pump based on the Hall waveforms. In the event of an open-circuit fault (or open-circuit phase loss) in the cooling water pump, the rotor speed of the cooling water pump motor will decrease. Consequently, the speed calculated from the Hall waveform will be lower than the rotor speed during normal operation. Correspondingly, during normal operation, the speed difference between the speed command received by the cooling water pump and the actual speed will not be too large, for example, the speed difference will not exceed one percent. Therefore, the speed fluctuation rate can be calculated based on the difference in rotor speed between two time intervals.

[0062] If the rotor speed of the cooling water pump is lower than the set rotor speed during normal operation, the rotor data is determined to be abnormal. The set rotor speed can be obtained by those skilled in the art based on actual test results; for example, the set rotor speed can be 7200 revolutions per minute.

[0063] If the rotational speed fluctuation rate of the cooling water pump rotor exceeds the set fluctuation rate during normal operation, the rotor data is determined to be abnormal. For example, the set fluctuation rate can be a value such as one percent, which can be obtained by those skilled in the art based on actual test results, and is not limited in detail here.

[0064] In another example, the domain controller can also acquire the rotor position angle estimation difference output by the flux linkage observer. This rotor position angle estimation difference can be understood as the difference between the estimated rotor position angle and the actual rotor position angle. It is used to determine whether the rotor position of the cooling water pump is abnormal. If the rotor position angle estimation difference exceeds the set angle difference value under normal operating conditions, it is determined that the estimated rotor position deviates too much from the actual position, and the rotor data is abnormal. A large rotor position angle estimation difference can lead to a decrease in the torque of the cooling water pump, increased vibration, etc. The set angle difference value can be obtained by those skilled in the art based on actual test results, and is not limited in detail here.

[0065] Alternatively, the domain controller can estimate the difference between at least two rotor position angles detected at two time intervals and calculate the rotational speed fluctuation rate of the cooling water pump. If the rotational speed fluctuation rate of the cooling water pump rotor exceeds a set fluctuation rate during normal operation, the rotor data is determined to be abnormal. For example, the set fluctuation rate could be a value such as one percent, which can be obtained by those skilled in the art based on actual test results, and is not further limited here.

[0066] S203. If any of the motor parameters, including the three-phase current imbalance, rotor data, and pump vibration data, are found to be abnormal, the current data that meets the predicted open circuit condition is determined, and the corresponding target phase experiences an open circuit fault.

[0067] In this embodiment of the invention, if any one of the motor parameters—the three-phase current imbalance, rotor data, and water pump vibration data—is detected to be abnormal, the current data that meets the predicted open-circuit condition is determined using a fault detection strategy based on the abnormal operating conditions of the two parameters. The corresponding target phase then experiences an open-circuit fault. For example, if only the V-phase current Iv meets the predicted open-circuit condition and an abnormality is detected in the three-phase current imbalance, the V-phase of the cooling water pump is determined to have an open-circuit fault. As another example, if only the V-phase current Iv meets the predicted open-circuit condition and no abnormalities are detected in the three-phase current imbalance, rotor data, and water pump vibration data, the cooling water pump is determined not to have an open-circuit fault. Yet another example, if both the V-phase current Iv and the W-phase current Iw meet the predicted open-circuit condition, and abnormalities are detected in the three-phase current imbalance, rotor data, or water pump vibration data, the V-phase and W-phase of the cooling water pump are determined to have open-circuit faults.

[0068] In summary, when a single-phase current is used to predict a suspected open circuit in a corresponding phase, the motor parameters of one of the affected cooling water pumps under the open circuit condition are combined for prediction. This allows for collaborative detection of multiple data sources, eliminating the probability of other operating conditions where a single parameter anomaly matches the open circuit condition. This reduces the misjudgment rate of the open circuit fault of the cooling water pump and improves the accuracy of open circuit phase location.

[0069] S204. Perform an application layer restart, and after each application layer restart step is completed, reacquire the three-phase current data of the cooling water pump, and combine the three-phase current data with at least one of the motor parameters to determine whether there is a target phase with an open circuit fault.

[0070] In this embodiment of the invention, application-layer restart eliminates the need to initialize underlying hardware and start all drivers, and retains fault logs, thus improving fault recovery efficiency. Therefore, when an open-circuit fault is determined in the cooling water pump, an application-layer restart is performed. After completing the application-layer restart step, the three-phase current data of the cooling water pump is reacquired, and combined with the three-phase current data and at least one of the motor parameters, it is determined whether there is a target phase with an open-circuit fault. In other words, after completing the application-layer restart step, steps S201 to S203 are repeated. If, after executing S203, a target phase with an open-circuit fault is determined, step S204 is executed, and so on, to eliminate operational faults caused by software-detected open-circuit conditions.

[0071] S205. If the restart threshold reaches the set safety threshold and there is still a target phase with an open circuit fault, match the open circuit fault information associated with the target with the open circuit fault and upload it to the application layer.

[0072] In this embodiment of the invention, when a target phase still has an open-circuit fault after multiple restarts—for example, when the accumulated restart threshold reaches (greater than or equal to) a set safety threshold and the target phase still has an open-circuit fault—the occurrence of an open-circuit fault due to software malfunction can be ruled out. The corresponding open-circuit fault information is then uploaded to the application layer, thereby preserving the open-circuit fault information for accurate location of the target phase and rapid repair. The set safety threshold can be determined by those skilled in the art based on actual redundancy requirements; for example, the set safety threshold can be 8, 9, 10, or 12, etc., and is not limited in this context.

[0073] If no open circuit fault is detected after multiple restarts at the application layer, it is determined that the fault was caused by the software operation, which detected the open circuit condition and has been repaired by restarting at the application layer. In this case, it can be determined that the three phases of the cooling water pump have not experienced an open circuit fault and the cooling water pump is in normal operating condition.

[0074] In one or more embodiments, considering that the rotor data of the cooling water pump under normal operating conditions differs significantly between the startup phase and the running phase, the domain controller can monitor the rotor data in stages according to the current stage. The startup phase refers to the period from the moment the cooling water pump is powered on until its speed stabilizes.

[0075] The domain controller can obtain the rotor position and rotor speed through Hall signals. When the cooling water pump is powered on, the rotor shaft is reset to an initial position, i.e., the set rotor position. If the rotor position is not reset to the set rotor position, the pre-positioning is determined to have failed, and the rotor data is abnormal.

[0076] If the rotor position is reset to the set rotor position, and the rotor speed does not reach the expected speed value within a preset time period, it is determined that the cooling water pump cannot start due to insufficient torque caused by an open-circuit fault after successful pre-positioning, and the corresponding rotor speed is zero. Alternatively, the rotor speed increases very slowly, causing open-loop acceleration timeout, for example, failing to reach the expected speed value within a preset time period. In this case, the rotor data is determined to be abnormal. For example, the expected speed value may be a critical speed value characterizing the cooling water pump entering the operating stage. Those skilled in the art can determine this based on actual test results, and no further limitations are made here.

[0077] Reference Figure 3 As shown in the figure, this embodiment of the invention also provides another method for detecting open circuit faults, the method may include:

[0078] S301. Obtain the three-phase current data of the cooling water pump.

[0079] In this embodiment of the invention, the description of S301 refers to the description of S201 described above.

[0080] S302. If at least one phase current data in the three-phase current data meets the predicted open circuit condition, monitor two of the following motor parameters: three-phase current imbalance, rotor data, and water pump vibration data.

[0081] In this embodiment of the invention, since even when single-phase current data meets the predicted open-circuit condition, there may also be current changes corresponding to other operating conditions that meet the non-open-circuit condition, in order to reduce the false alarm rate of open-circuit faults, other motor parameters that change due to the open-circuit condition can be further monitored. In one example, the domain controller can monitor at least two of the following motor parameters: three-phase current imbalance, rotor data, and pump vibration data.

[0082] The three-phase current imbalance can be used to assess whether the three-phase current is in a balanced state. When the cooling water pump's three-phase current is under normal operating conditions, the cumulative sum of the three-phase current data is zero, and the amplitude of each phase current is equal, resulting in a very small three-phase current imbalance. When one phase of the three-phase current is in an open-circuit condition, the currents of the other two phases will increase. This disrupts the balance of the three-phase current, leading to a significant increase in the three-phase current imbalance.

[0083] When the cooling water pump operates in an open-circuit condition, it may cause abnormal vibrations in the cooling water pump.

[0084] When the cooling water pump operates in an open-circuit condition, it can cause a decrease in the pump's output speed or even stop. Therefore, the rotor data can be used to detect whether the cooling water pump is experiencing abnormal operating conditions such as a decrease in output speed or even stoppage.

[0085] Considering that the above-mentioned data judgments are based on theoretical values ​​under normal open-circuit conditions, the electrical and / or physical performance of the cooling water pump may degrade with long-term use, resulting in fluctuations in the normal operating parameters of the cooling water pump under different time periods. Therefore, in cases where a single-phase current prediction indicates a suspected open circuit, integrating at least two cooling water pump motor parameters for collaborative detection can further reduce the false positive rate of open-circuit faults in the cooling water pump.

[0086] S303. If two of the motor parameters in the three-phase current imbalance, rotor data, and water pump vibration data are found to be abnormal, the current data that meets the predicted open circuit condition is determined, and the corresponding target phase has an open circuit fault.

[0087] If any two of the motor parameters—the three-phase current imbalance, rotor data, and water pump vibration data—are detected to be abnormal, the current data that meets the pre-judged open-circuit condition is determined using a fault detection strategy based on the abnormal operating conditions of the three parameters. The corresponding target phase then experiences an open-circuit fault. For example, if only the V-phase current Iv meets the pre-judged open-circuit condition, and abnormalities are detected in the three-phase current imbalance and rotor data, the V-phase of the cooling water pump is determined to have an open-circuit fault. As another example, if only the V-phase current Iv meets the pre-judged open-circuit condition, and no abnormalities are detected in the three-phase current imbalance, rotor data, and water pump vibration data, the cooling water pump is determined not to have an open-circuit fault. For example, if the V-phase current Iv and the W-phase current Iw respectively meet the predicted open circuit conditions, and abnormalities are detected in the three-phase current imbalance and rotor data, or abnormalities are detected in the three-phase current imbalance and water pump vibration data, or abnormalities are detected in the rotor data and water pump vibration data, then it is determined that the V-phase and W-phase of the cooling water pump have an open circuit fault.

[0088] In one or more embodiments, considering that the above-mentioned data determinations are based on theoretical values ​​under normal open-circuit conditions, and that the electrical and / or physical performance of the cooling water pump may degrade with long-term use, resulting in fluctuations in the normal parameters of the cooling water pump under normal operating conditions at different times, the following approach is adopted: When a single-phase current prediction indicates a suspected open circuit, the above three motor parameters of the cooling water pump are combined for collaborative detection. Specifically, open-circuit fault determination is performed using four parameters: single-phase current data, three-phase current imbalance, rotor data, and pump vibration data. This completely eliminates other operating conditions besides the open-circuit condition that could affect the changes in at most three of the above parameters, thus improving the fault detection accuracy of this embodiment.

[0089] In summary, this invention discloses an open-circuit fault detection method. The method may include first acquiring three-phase current data of a cooling water pump, and, if at least one phase current data satisfies the predicted open-circuit condition, monitoring at least one of the following motor parameters: three-phase current imbalance, rotor data, and pump vibration data. If any one of these motor parameters is detected to be abnormal, the current data that satisfies the predicted open-circuit condition is determined, and the corresponding target phase experiences an open-circuit fault. Therefore, when predicting a suspected open circuit based on single-phase current, at least one cooling water pump motor parameter can be fused for prediction. This allows for multi-data collaborative detection, reducing the false positive rate of open-circuit faults in the cooling water pump and improving the accuracy of open-circuit phase location.

[0090] It should be noted that, for the sake of simplicity, the method embodiments are all described as a series of actions. However, those skilled in the art should understand that the embodiments of this application are not limited to the described order of actions, because according to the embodiments of this application, some steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also understand that the embodiments described in the specification are all preferred embodiments, and the actions involved are not necessarily required by the embodiments of this application.

[0091] Reference Figure 4 This invention also provides a three-phase open-circuit fault detection device, which may include:

[0092] The current data acquisition module 401 is used to acquire the three-phase current data of the cooling water pump.

[0093] The motor parameter monitoring module 402 is used to monitor at least one of the following motor parameters when at least one phase current data in the three-phase current data meets the predicted open circuit condition: three-phase current imbalance, rotor data, and water pump vibration data.

[0094] The fault determination module 403 is used to determine the current data that meets the predicted open circuit condition if any motor parameter among the three-phase current imbalance, rotor data and water pump vibration data is detected to be abnormal, and the corresponding target phase has an open circuit fault.

[0095] In one or more embodiments, when the cooling water pump is in operation, the motor parameter monitoring module 402 is used to:

[0096] Acquire a Hall effect waveform and determine the rotor speed or speed fluctuation rate of the cooling water pump based on the Hall effect waveform. Alternatively, acquire the rotor position angle estimation difference or speed fluctuation rate.

[0097] The device further includes an anomaly determination module, the anomaly determination module being used for:

[0098] If the rotor speed of the cooling water pump is lower than the set rotor speed during normal operation, or if the speed fluctuation rate of the cooling water pump exceeds the set fluctuation rate during normal operation, the rotor data is determined to be abnormal. Alternatively,

[0099] If the estimated difference in rotor position angle exceeds the set angle difference value under normal operation, or if the speed fluctuation rate of the cooling water pump exceeds the set fluctuation rate under normal operation, the rotor data is determined to be abnormal.

[0100] In one or more embodiments, when the cooling water pump is in the start-up phase, the motor parameter monitoring module 402 is used to obtain the rotor position and rotor speed.

[0101] The device further includes an anomaly determination module, which is used to: determine that the rotor data is abnormal if the rotor position is not reset to the set rotor position; determine that the rotor data is abnormal if the rotor position is reset to the set rotor position and the rotor speed does not reach the expected speed value within a preset time period, wherein the start-up stage refers to the stage from the moment the cooling water pump is powered on to the stage when the speed is stable.

[0102] In one or more embodiments, the anomaly determination module is used to: determine that the water pump vibration data is abnormal when the water pump vibration data exceeds the set vibration amplitude under normal operation.

[0103] In one or more embodiments, the motor parameter monitoring module 402 is used for:

[0104] The maximum and minimum current values ​​of the three-phase current data within a single acquisition cycle are selected, and the average value of the three-phase current data within a single acquisition cycle is calculated. Based on the maximum current value, the minimum current value, and the average value of the three-phase current, the three-phase current imbalance is calculated.

[0105] The anomaly determination module is used to determine that an anomaly in the three-phase current imbalance is detected when the three-phase current imbalance continues to meet the current anomaly condition.

[0106] In one or more embodiments, the device may further include a fault recovery module, which can be used to:

[0107] An application-layer restart is performed, and after each application-layer restart step is completed, the three-phase current data of the cooling water pump is reacquired. The three-phase current data and at least one of the motor parameters are combined to determine whether there is a target phase with an open circuit fault.

[0108] If the restart threshold reaches the set safety threshold and there are still target phases with open circuit faults, the open circuit fault information associated with the target with the open circuit fault is matched and uploaded to the application layer.

[0109] This invention also provides a domain controller configured to execute the open-circuit fault detection method described in any of the above embodiments.

[0110] This invention also provides a thermal management system, which includes a three-phase open-circuit fault detection device as described in any of the above embodiments and a domain controller as described in the above embodiments.

[0111] In this embodiment of the invention, the thermal management system with the domain controller described in the above embodiments can reduce the false positive rate of open-circuit faults in the cooling water pump and improve the accuracy of open-circuit phase location through multi-data collaborative detection. Furthermore, it can urgently recover from detected open-circuit faults in the thermal piping system by means of application-layer restart, thereby improving the operational stability of the thermal piping system.

[0112] This invention also provides a vehicle that includes a thermal management system as described in the above embodiments.

[0113] In summary, the embodiments of the present invention can first acquire the three-phase current data of the cooling water pump, and when at least one phase current data in the three-phase current data meets the predicted open circuit condition, monitor at least one of the following motor parameters: three-phase current imbalance, rotor data, and water pump vibration data. If any of the motor parameters among the three-phase current imbalance, rotor data, and water pump vibration data is detected to be abnormal, the current data that meets the predicted open circuit condition is determined, and the corresponding target phase has an open circuit fault. Therefore, when predicting a suspected open circuit in a corresponding phase based on single-phase current, at least one motor parameter of the cooling water pump can be fused for prediction, thereby reducing the false positive rate of the open circuit fault of the cooling water pump and improving the accuracy of open circuit phase location through multi-data collaborative detection.

[0114] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0115] It will be readily apparent to those skilled in the art that any combination of the above embodiments is feasible, and therefore any combination of the above embodiments is an implementation scheme of the present invention. However, due to space limitations, this specification will not describe them in detail here.

[0116] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0117] Similarly, it should be understood that, in order to simplify the invention and aid in understanding one or more of the various aspects of the invention, in the description of exemplary embodiments of the invention above, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof.

[0118] Furthermore, those skilled in the art will understand that although some embodiments described herein include certain features included in other embodiments but not others, combinations of features from different embodiments are intended to be within the scope of the invention and form different embodiments. For example, in the claims, any of the claimed embodiments can be used in any combination.

Claims

1. A method for detecting open-circuit faults, characterized in that, The method includes: Obtain the three-phase current data of the cooling water pump; If at least one phase current data in the three-phase current data meets the predicted open circuit condition, monitor at least one of the following motor parameters: three-phase current imbalance, rotor data, and water pump vibration data; If any motor parameter is detected to be abnormal among the three-phase current imbalance, rotor data, and pump vibration data, and the current data that meets the predicted open circuit condition is determined, the corresponding target phase will experience an open circuit fault.

2. The open-circuit fault detection method according to claim 1, characterized in that, When the cooling water pump is in operation, the monitored rotor data includes: The method further includes: acquiring a Hall waveform and determining the rotor speed or speed fluctuation rate of the cooling water pump based on the Hall waveform; the method also includes: If the rotor speed of the cooling water pump is lower than the set rotor speed during normal operation, or if the speed fluctuation rate of the cooling water pump exceeds the set fluctuation rate during normal operation, the rotor data is determined to be abnormal; or... The method further includes obtaining the rotor position angle estimation difference or speed fluctuation rate; If the estimated difference in rotor position angle exceeds the set angle difference value under normal operation, or if the speed fluctuation rate of the cooling water pump exceeds the set fluctuation rate under normal operation, the rotor data is determined to be abnormal.

3. The open-circuit fault detection method according to claim 1, characterized in that, When the cooling water pump is in the start-up phase, the monitored rotor data includes: The method further includes obtaining the rotor position and rotor speed; If the rotor position is not reset to the set rotor position, the rotor data is determined to be abnormal; If the rotor position is reset to the set rotor position, and the rotor speed does not reach the expected speed value within a preset time period, the rotor data is determined to be abnormal. The startup phase refers to the phase from the moment the cooling water pump is powered on until the speed stabilizes.

4. The open-circuit fault detection method according to claim 1, characterized in that, The method further includes: If the vibration data of the water pump exceeds the set vibration amplitude during normal operation, the water pump vibration data is determined to be abnormal.

5. The open-circuit fault detection method according to claim 1, characterized in that, The monitoring of three-phase current imbalance includes: The maximum and minimum current values ​​of the three-phase current data within a single acquisition cycle are selected, and the average value of the three-phase current data within a single acquisition cycle is calculated. The three-phase current imbalance is calculated based on the maximum current value, the minimum current value, and the average three-phase current; the method further includes: If the three-phase current imbalance continues to meet the current abnormality condition, it is determined that the three-phase current imbalance is abnormal.

6. The open-circuit fault detection method according to any one of claims 1-5, characterized in that, The method further includes: Perform an application-layer restart, and after each application-layer restart step is completed, reacquire the three-phase current data of the cooling water pump, and combine the three-phase current data with at least one of the motor parameters to determine whether there is a target phase with an open circuit fault; If the restart threshold reaches the set safety threshold and there are still target phases with open circuit faults, the open circuit fault information associated with the target with the open circuit fault is matched and uploaded to the application layer.

7. A three-phase open-circuit fault detection device, characterized in that, The device includes: The current data acquisition module is used to acquire the three-phase current data of the cooling water pump; The motor parameter monitoring module is used to monitor at least one of the following motor parameters when at least one phase current data in the three-phase current data meets the predicted open circuit condition: three-phase current imbalance, rotor data, and water pump vibration data. The fault determination module is used to determine the current data that meets the predicted open circuit condition if any motor parameter among the three-phase current imbalance, rotor data, and water pump vibration data is detected to be abnormal, and the corresponding target phase has an open circuit fault.

8. A domain controller, characterized in that, The domain controller is configured to perform the open-circuit fault detection method according to any one of claims 1-6.

9. A thermal management system, characterized in that, The thermal management system includes the three-phase open-circuit fault detection device as described in claim 7, and the domain controller as described in claim 8.

10. A vehicle, characterized in that, The vehicle includes the thermal management system as described in claim 9.

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