A method, device, electronic device and storage medium for detecting abnormal current

Abstract

The present invention discloses a current anomaly detection method, device, electronic device and storage medium, which relate to the field of motor control. The method obtains the real-time N-phase current of the N-phase motor in the current cycle, determines the reference current value corresponding to each phase of the N-phase motor in a preset coordinate system, and / or transforms the real-time N-phase current to the preset coordinate system to obtain each corresponding real-time current value; determines whether there is a current abnormal phase according to the sum of all real-time current values; if there is a current abnormal phase, locates the current abnormal phase and the current normal phase according to the difference between each corresponding reference current value and the real-time current value. It can be seen that the scheme can quickly and efficiently locate the specific phase of the current sampling abnormality, rather than just identifying the existence of the current abnormality, and solves the stability and reliability problems caused by single-phase current sampling abnormality in PMSM control.

Description

Technical Field

[0001] The present invention relates to the field of motor control, and in particular to a current abnormality detection method, device, electronic equipment and storage medium. Background Art

[0002] In the vector control of permanent magnet synchronous motor (PMSM), accurate current detection is the key to achieve efficient torque control and fault diagnosis. However, due to sensor failure, line interference or environmental factors, current sampling may be abnormal, affecting system stability and reliability.

[0003] To solve the above problems, the circuit topology structure at the hardware level is usually upgraded or improved, or a zero-vector sampling strategy is adopted to sample the current during the zero-vector time period in the motor control to determine whether the current is abnormal. However, neither of the above two methods can directly locate the specific phase of the sampling abnormality, which limits the speed and efficiency of troubleshooting. Summary of the invention

[0004] The purpose of the present invention is to provide a current anomaly detection method, device, electronic device and storage medium, which can quickly and efficiently locate the specific phase of the current sampling anomaly, rather than just identifying the existence of the current anomaly, and solve the stability and reliability problems caused by single-phase current sampling anomaly in PMSM control.

[0005] In a first aspect, the present application provides a current anomaly detection method, comprising:

[0006] Get the real-time N-phase current of the N-phase motor in the current cycle; N ≥ 3, and N is an integer;

[0007] Determine a reference current value corresponding to each phase of the N-phase motor in a preset coordinate system, and / or transform the real-time N-phase current to the preset coordinate system to obtain each corresponding real-time current value; the preset coordinate system is an N-phase stationary coordinate system or a two-phase stationary coordinate system;

[0008] Determine whether there is an abnormal current phase according to the sum of all the real-time current values;

[0009] If there is an abnormal current phase, the abnormal current phase and the normal current phase are located according to the difference between each corresponding reference current value and the real-time current value.

[0010] Optionally, after locating the abnormal current phase and the normal current phase according to the difference between each corresponding reference current value and the real-time current value, the method further includes:

[0011] Calculating the corrected current value of the abnormal current phase according to the real-time current values ​​of all the normal current phases;

[0012] In the next cycle, the N-phase motor is controlled according to the reference current value, the correction current value and the real-time current value of the normal current phase.

[0013] Optionally, calculating the corrected current value of the abnormal current phase according to the real-time current values ​​of all the normal current phases includes:

[0014] Calculating the sum of the real-time current values ​​of all the normal current phases;

[0015] The sum of the real-time current values ​​of the normal current phase is inverted to obtain the corrected current value of the abnormal current phase.

[0016] Optionally, determining a reference current value corresponding to each phase of the N-phase motor in a preset coordinate system includes:

[0017] Obtaining a target current of the N-phase motor in a synchronous rotating coordinate system;

[0018] Let the two-phase stationary coordinate system The axis coincides with the axis of each phase in the N phases, and an inverse Park transformation is performed on the target current to obtain a reference current value for each corresponding phase in a two-phase stationary coordinate system.

[0019] Optionally, determining a reference current value corresponding to each phase of the N-phase motor in a preset coordinate system includes:

[0020] Obtaining a target current of the N-phase motor in a synchronous rotating coordinate system;

[0021] The target current is subjected to inverse Park transformation and inverse Clark transformation in sequence to obtain each corresponding reference current value in an N-phase stationary coordinate system.

[0022] Optionally, determining whether there is an abnormal current phase according to the sum of all the real-time current values ​​includes:

[0023] Calculating a sum of all the real-time current values, and determining whether an absolute value of the sum is greater than a first threshold;

[0024] If it is greater than the first threshold, it is determined that the abnormal current phase exists;

[0025] If it is less than or equal to the first threshold, it is determined that the abnormal current phase does not exist, and in the next cycle, the N-phase motor is controlled according to the reference current value and the real-time N-phase current.

[0026] Optionally, locating the abnormal current phase and the normal current phase according to the difference between each corresponding reference current value and the real-time current value comprises:

[0027] Calculating the difference between each corresponding reference current value and the real-time current value;

[0028] If there is any corresponding difference greater than the second threshold, and the difference of the remaining N-1 phases is less than or equal to the second threshold, the phase whose difference is greater than the second threshold is determined to be the abnormal current phase, and the phase whose difference is less than or equal to the second threshold is determined to be the normal current phase.

[0029] In a second aspect, the present application provides a current anomaly detection device, comprising:

[0030] An acquisition module is used to acquire the real-time N-phase current of the N-phase motor in the current cycle; N ≥ 3, and N is an integer;

[0031] a transformation module, used to determine a reference current value corresponding to each phase of the N-phase motor in a preset coordinate system, and / or transform the real-time N-phase current to the preset coordinate system to obtain each corresponding real-time current value; the preset coordinate system is an N-phase stationary coordinate system or a two-phase stationary coordinate system;

[0032] A judgment unit, used for determining whether there is an abnormal current phase according to the sum of all the real-time current values;

[0033] The positioning unit is used for positioning the abnormal current phase and the normal current phase according to the difference between each corresponding reference current value and the real-time current value when the abnormal current phase exists.

[0034] In a third aspect, the present application provides an electronic device, including:

[0035] Memory for storing computer programs;

[0036] The processor is used to implement the steps of the current anomaly detection method as described above when executing a computer program.

[0037] In a fourth aspect, the present application provides a computer-readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the steps of the current anomaly detection method as described above are implemented.

[0038] The present application provides a current anomaly detection method, device, electronic device and storage medium, which relates to the field of motor control. The method obtains the real-time N-phase current of the N-phase motor in the current cycle, determines the reference current value corresponding to each phase of the N-phase motor in a preset coordinate system, and / or transforms the real-time N-phase current to the preset coordinate system to obtain each corresponding real-time current value; determines whether there is a current abnormal phase according to the sum of all real-time current values; if there is a current abnormal phase, locates the current abnormal phase and the current normal phase according to the difference between each corresponding reference current value and the real-time current value. It can be seen that this scheme can quickly and efficiently locate the specific phase of the current sampling abnormality, rather than just identifying the existence of the current abnormality, and solves the stability and reliability problems caused by single-phase current sampling abnormality in PMSM control. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0040] Figure 1 A flow chart of a current anomaly detection method provided by the present invention;

[0041] Figure 2 A schematic diagram of the first Clark transformation provided by the present invention;

[0042] Figure 3 A schematic diagram of the second Clark transform provided by the present invention;

[0043] Figure 4 A schematic diagram of the third Clark transform provided by the present invention;

[0044] Figure 5 A structural diagram of the three-phase current error phase fast fault-tolerant control provided by the present invention;

[0045] Figure 6 A schematic diagram of a specific implementation of a current anomaly detection method provided by the present invention;

[0046] Figure 7 A schematic diagram of a specific implementation of another current anomaly detection method provided by the present invention;

[0047] Figure 8 This is a schematic diagram of the current anomaly detection device provided by the present invention. DETAILED DESCRIPTION

[0048] The core of the present invention is to provide a current anomaly detection method, device, electronic device and storage medium, which can quickly and efficiently locate the specific phase of the current sampling anomaly, rather than just identifying the existence of the current anomaly, and solve the stability and reliability problems caused by single-phase current sampling anomaly in PMSM control.

[0049] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0050] First, as Figure 1 As shown, the present application provides a current anomaly detection method, which can be applied to a processor or controller based on an N-phase permanent magnet synchronous motor with an N-phase current sensor, and the method includes:

[0051] S11: Obtain the real-time N-phase current of the N-phase motor in the current cycle; N ≥ 3, and N is an integer;

[0052] In this step, the real-time N-phase current obtained by sampling in the current cycle is first obtained, where N represents the number of phases of the motor, N≥3, and N is an integer. The core of this step is to accurately monitor the working state of the motor by sampling the different phase currents of the motor.

[0053] In a multi-phase motor system, N-phase current (N≥3) is usually used to describe the current distribution of each phase. The value of N can be 3, 5, etc., depending on the specific design and application scenario of the motor. For example, for a three-phase motor (N=3), the current of each phase corresponds to the current state of the motor at each moment; while for a five-phase motor (N=5), more phases are involved, and current monitoring needs to consider more phase information. By collecting the currents of these different phases, the operating status of the motor can be fully reflected.

[0054] In this step, the real-time N-phase current is the actual current value collected by the current sensor in the current cycle. The real-time current value reflects the current distribution when the motor is actually running.

[0055] S12: determining a reference current value corresponding to each phase of the N-phase motor in a preset coordinate system, and / or transforming the real-time N-phase current to the preset coordinate system to obtain each corresponding real-time current value; the preset coordinate system is an N-phase stationary coordinate system or a two-phase stationary coordinate system;

[0056] In this step, the reference current value of each phase of the N-phase motor in a preset coordinate system (such as an N-phase stationary coordinate system or a two-phase stationary coordinate system) is determined. The reference current value is usually an ideal current value calculated based on the normal operating state of the motor or a theoretical model. Next, the real-time collected N-phase current is converted to the preset coordinate system through coordinate transformation to obtain the real-time current value of each corresponding phase. The purpose of the coordinate transformation is to convert multi-phase current from a natural coordinate system to the same coordinate system that is easier to analyze and process, thereby simplifying the complexity of current anomaly detection. At this point, in the preset coordinate system, by comparing the reference current value and the real-time current value, the current anomaly can be more intuitively identified.

[0057] Specifically, the preset coordinate system can be an N-phase stationary coordinate system or a two-phase stationary coordinate system (or a dual two-phase stationary coordinate system, etc.), depending on the specific application requirements. For example, when N is 3, the three-phase stationary coordinate system refers to the ABC coordinate system, and the two-phase stationary coordinate system refers to Coordinate system.

[0058] S13: Determine whether there is an abnormal current phase according to the sum of all real-time current values;

[0059] In this step, the overall information of multi-phase current is used to comprehensively evaluate the current of each phase to determine whether there is any current anomaly in the system. In the motor control system, under normal circumstances, the currents of multiple phases should be in a certain balance state (e.g., in an ideal state, the sum of all real-time current values ​​is zero, or the absolute value of the sum of the currents of each phase should be close to zero). This balance state reflects the uniform distribution of the loads of each phase of the motor. If the current of one of the phases is abnormal (for example, due to sensor failure, circuit interference, or uneven motor load), it will lead to abnormal distribution of current, thereby affecting the stability of the entire motor system.

[0060] In order to detect this abnormality, the sum of all phase currents or their average value is calculated by summing the multi-phase currents sampled in real time. This sum value can reflect whether the current distribution of the entire motor system is normal. If a current abnormality occurs, the sum or distribution of the entire current will be inconsistent due to the deviation of the current of a certain phase from the normal value, resulting in a result that is significantly deviated from the normal range. Therefore, by comparing the current sum value, the existence of current abnormality is detected.

[0061] S14: If there is an abnormal current phase, locate the abnormal current phase and the normal current phase according to the difference between each corresponding reference current value and the real-time current value.

[0062] In this step, by comparing the difference between the reference current value and the real-time current value, it is identified which phases have abnormalities, thereby determining the specific location of the current abnormality and further locating the abnormal type of the current.

[0063] In the motor control system, the reference current value represents the ideal current value calculated based on the motor control algorithm or expected behavior, while the real-time current value is the current value measured in real time by the sensor. Under normal circumstances, the reference current value and the real-time current value should be very close. However, due to factors such as sensor failure, circuit interference or load imbalance, the current of some phases may deviate from the normal range, resulting in a large difference between the reference current value and the real-time current value.

[0064] In this step, the difference between the reference current value and the real-time current value of each phase is first calculated. These differences reflect the degree of abnormality of each phase current. If the difference is large, it indicates that the current of the phase is abnormal, which may be caused by sensor failure, current sampling error or uneven motor load. On the contrary, if the difference is small, it means that the current of the phase is within the normal range.

[0065] By analyzing the difference of all phase currents, it is possible to accurately locate which phase currents are abnormal and further distinguish which phases are normal. Especially in multi-phase motors, this method can accurately determine the specific abnormal phase, avoiding the limitation of traditional methods that can only detect the existence of abnormalities but cannot locate their specific locations.

[0066] In summary, the current anomaly detection method provided by the present application obtains the real-time N-phase current of the N-phase motor in the current cycle, determines the reference current value corresponding to each phase of the N-phase motor in the preset coordinate system, and / or transforms the real-time N-phase current to the preset coordinate system to obtain each corresponding real-time current value; determines whether there is a current abnormal phase based on the sum of all real-time current values; if there is a current abnormal phase, locates the current abnormal phase and the current normal phase based on the difference between each corresponding reference current value and the real-time current value. It can be seen that this scheme can quickly and efficiently locate the specific phase of the current sampling abnormality, rather than just identifying the existence of the current abnormality, and solves the stability and reliability problems caused by single-phase current sampling abnormality in PMSM control.

[0067] Based on the above embodiments:

[0068] As a preferred embodiment, after locating the abnormal current phase and the normal current phase according to the difference between each corresponding reference current value and the real-time current value, the method further includes:

[0069] Calculate the corrected current value of the abnormal current phase according to the real-time current values ​​of all normal current phases;

[0070] In the next cycle, the N-phase motor is controlled according to the reference current value, the correction current value and the real-time current value of the normal current phase.

[0071] Since the occurrence of abnormal current phases may be caused by sensor failure, line problems or uneven load, these abnormal currents will affect the overall performance and control accuracy of the motor.

[0072] Therefore, in this embodiment, in order to avoid the influence of abnormal current on the motor control system, after locating the abnormal current phase and the normal current phase, information is extracted from the current of other normal phases, and further based on the real-time current value of the normal current phase, the corrected current value of the abnormal current phase is calculated. The core is to use the information of the normal current phase to correct the abnormal current value phase, thereby restoring the normal operation of the motor.

[0073] In this way, the abnormal current can be corrected in the next cycle, thereby maintaining the stability of the motor control system and avoiding system failure or performance degradation caused by abnormal current. By calculating the corrected current value in real time, the control strategy can be dynamically adjusted to ensure balanced operation of the motor.

[0074] As a preferred embodiment, the corrected current value of the abnormal current phase is calculated according to the real-time current values ​​of all normal current phases, including:

[0075] Calculate the sum of the real-time current values ​​of all normal current phases;

[0076] The sum of the real-time current values ​​of the normal current phase is inverted to obtain the corrected current value of the abnormal current phase.

[0077] Specifically, when calculating the corrected current value of the abnormal current phase, the real-time current values ​​of all normal current phases are summed. Under normal circumstances, the sum of the current values ​​of the normal current phases and the corrected current value of the abnormal phase should be zero, or within the first threshold range, balanced and relatively stable.

[0078] In order to correct the abnormal current, the real-time current value and value of the normal current phase are inverted to obtain the corrected current value of the abnormal current phase. This corrected current value is the reconstructed normal real-time current value of the abnormal current phase.

[0079] Treating the corrected current value as the normal real-time current value of the abnormal current phase can effectively eliminate the system imbalance caused by the abnormal current and restore the stability of the motor control system. In the next cycle, the reference current value, the corrected current value, and the real-time current value of the normal current phase are used to control the motor to ensure that the motor maintains efficient operation and precise regulation throughout the entire control cycle. In this way, not only can a timely response be made when a current anomaly occurs, but the normal working state of the motor can also be maintained by dynamically adjusting and correcting the current value, thereby improving the robustness and reliability of the control system.

[0080] As a preferred embodiment, determining a reference current value corresponding to each phase of an N-phase motor in a preset coordinate system includes:

[0081] Obtain the target current of the N-phase motor in the synchronous rotating coordinate system;

[0082] Let the two-phase stationary coordinate system The axis coincides with the axis of each phase, and the target current is subjected to an inverse Park transformation to obtain the reference current value of each corresponding phase in the two-phase stationary coordinate system.

[0083] In this embodiment, when the preset coordinate system is a two-phase stationary coordinate system, the target current of the N-phase motor in the synchronous rotating coordinate system is first obtained, and then the target current and the real-time N-phase current (taking a three-phase motor as an example) are transformed to the two-phase stationary coordinate system to perform accurate current anomaly detection and positioning.

[0084] First, for the target current, the α axis of the two-phase stationary coordinate system is aligned with each phase axis of the motor (A axis, B axis, and C axis respectively), and the target current is converted from the synchronous rotating coordinate system (dq coordinate system) to the two-phase stationary coordinate system through the inverse Park transformation. The key to the inverse Park transformation is to convert the current data in the rotating coordinate system into two components in the stationary coordinate system, usually expressed as the current components of the α axis and the β axis (only the current components of the α axis and the β axis are used in this embodiment). In this process, each current component (α-axis and β-axis) corresponds to the current performance of the motor in the stationary coordinate system.

[0085] For real-time N-phase current (such as the three-phase current of a three-phase motor), the same method is applied to each phase current. In this process, the α axis in the two-phase stationary coordinate system is first aligned with each phase axis of the motor, and then the phase current in the real-time N-phase current is subjected to Clark transformation to map the real-time data of the three-phase current to the two-phase stationary coordinate system. Clark transformation converts the three-phase current data into the current components in the two-phase stationary coordinate system by rotating the coordinate system (only the current components in this embodiment are used). The Clark transform can effectively extract the current component related to the motor rotor magnetic field, making the current data more suitable for analysis in a stationary coordinate system, and facilitating subsequent current anomaly detection and correction.

[0086] By transforming the target current in the synchronous rotating coordinate system and the real-time current value in the three-phase stationary coordinate system to the two-phase stationary coordinate system, the system can more accurately analyze the current data and detect current anomalies in the stationary coordinate system that is not affected by the rotational motion. This transformation provides a more stable and reliable data basis for the subsequent current anomaly positioning, correction and control, while avoiding the complex calculations and dynamic changes that may occur in the rotating coordinate system, thereby simplifying the current monitoring process and improving the accuracy and efficiency of detection.

[0087] As a preferred embodiment, determining a reference current value corresponding to each phase of an N-phase motor in a preset coordinate system includes:

[0088] Obtain the target current of the N-phase motor in the synchronous rotating coordinate system;

[0089] The target current is subjected to inverse Park transformation and inverse Clark transformation in sequence to obtain the reference current value of each corresponding phase in the N-phase stationary coordinate system.

[0090] In this embodiment, when the preset coordinate system is an N-phase stationary coordinate system, the target current of the N-phase motor in the synchronous rotating coordinate system is first obtained, and then the target current is transformed from the synchronous rotating coordinate system (dq coordinate system) to the N-phase stationary coordinate system to perform more accurate current anomaly detection. Taking a three-phase motor as an example, first, the target current is usually obtained through the rotating coordinate system (dq coordinate system) in the motor control system, where the currents of the d-axis and q-axis reflect the direct and cross-control components of the motor. However, in order to map the current information to the N-phase stationary coordinate system, a series of coordinate transformations must be performed on the target current.

[0091] The first step is to perform an inverse Park transform (reverse Park transform) on the target current. Park transform usually maps the current from a stationary coordinate system (such as the α-β coordinate system) to a rotating coordinate system (such as the dq coordinate system). The inverse Park transform remaps the current in the rotating coordinate system back to the stationary coordinate system. Through the inverse Park transform, the d-axis and q-axis current components in the rotating coordinate system are converted into two components in the stationary coordinate system (usually the α-axis and the β-axis). In this process, the dynamic characteristics of the current are eliminated, so that the current data no longer depends on the rotation state of the motor.

[0092] The second step is to perform an inverse Clark transform on the current result after the inverse Park transform. Clark transform is a linear transformation that converts three-phase current (such as a, b, and c phase currents) into two independent components (usually the α axis and the β axis), while the inverse Clark transform is to reversely transform the current data in the α-β coordinate system back to the N-phase stationary coordinate system. Through the inverse Clark transform, the data is restored to N real-time phase currents and mapped to the N-phase stationary coordinate system. This process not only retains the relative relationship between the currents of each phase, but also converts the current changes to the stationary coordinate system, which is convenient for subsequent analysis and monitoring.

[0093] Through the inverse Park and inverse Clark transformations, the target current is successfully converted from the rotating coordinate system to the current of each phase in the N-phase stationary coordinate system, so that the current of each phase can be represented and processed in the stationary coordinate system. This transformation method is particularly suitable for multi-phase motor systems, and can effectively eliminate the influence caused by the rotating reference coordinate system, providing a more stable analysis basis for subsequent current anomaly detection, fault location and motor control. In general, this method converts current information from a rotating coordinate system to a stationary coordinate system through a two-step coordinate transformation (inverse Park and inverse Clark transformation), simplifies subsequent processing, and improves the accuracy and reliability of current monitoring and control.

[0094] As a preferred embodiment, determining whether there is an abnormal current phase according to the sum of all real-time current values ​​includes:

[0095] Calculate the sum of all real-time current values, and determine whether the absolute value of the sum is greater than a first threshold;

[0096] If it is greater than the first threshold, it is determined that there is an abnormal current phase;

[0097] If it is less than or equal to the first threshold, it is determined that there is no abnormal current phase, and in the next cycle, the N-phase motor is controlled according to the target current and the real-time N-phase current.

[0098] In this embodiment, the presence or absence of an abnormal current phase is determined by calculating the sum of all real-time current values. Taking a three-phase motor as an example, the real-time current values ​​of each phase are summed to obtain an overall current sum value. Ideally, the current of a three-phase motor should be balanced, and its sum should be close to zero (i.e., zero in an ideal situation), because in a balanced state, the phase differences of the currents of each phase are fully compensated. Therefore, if the current in the system is normal and there is no abnormality, the sum of the phase currents should be close to zero, which means that the current distribution of the motor is balanced.

[0099] Specifically, the judgment steps are as follows: Calculate the sum of all real-time current values, that is, add the three-phase currents (assuming Ia, Ib, Ic) to get the total current value. If the motor is in normal working condition, the three-phase currents should be balanced and their sum should be close to zero. If the absolute value of the total current value is greater than the preset first threshold, it means that the current distribution is unbalanced, and there may be current abnormalities in some phases (such as current sensor failure, short circuit, uneven load, etc.). At this time, it is determined that there is an abnormal current phase.

[0100] If the absolute value of the calculated total current is less than or equal to the first threshold, indicating that the current distribution between the phases is relatively balanced and there is no obvious abnormality, it is determined that there is no abnormal current phase. At this time, the normal operation of the current system is guaranteed, and the motor control can continue to be performed according to the target current and the real-time current value to maintain the stable operation of the motor.

[0101] As a preferred embodiment, locating the abnormal current phase and the normal current phase according to the difference between each corresponding reference current value and the real-time current value includes:

[0102] Calculate the difference between each corresponding reference current value and the real-time current value;

[0103] If any corresponding difference exists that is greater than the second threshold, and the difference of the remaining N-1 phases is less than or equal to the second threshold, the phase whose difference is greater than the second threshold is determined to be an abnormal current phase, and the phase whose difference is less than or equal to the second threshold is determined to be a normal current phase.

[0104] In this embodiment, the abnormal current phase and the normal current phase are located by calculating the difference between the reference current value and the real-time current value of each phase. Taking a three-phase motor as an example, first, the difference is calculated for each phase based on the pre-calculated reference current value and the real-time current value obtained by actual sampling. Specifically, for each phase, the difference between the reference current value and the real-time current value of the phase is calculated, and this difference reflects the deviation between the actual change of the current and the reference value.

[0105] After the difference calculation is completed, the difference of each phase is compared with the preset second threshold. The second threshold is a standard value used to determine whether the current change is abnormal. If the current difference of a phase is greater than the second threshold, and the differences of the remaining N-1 phases are less than or equal to the second threshold, it is considered that the current of the phase is abnormal. This is because the abnormal current is usually manifested as a significant deviation in the current of a phase, causing the difference of the phase to exceed the normal tolerance range. In this way, the phase with abnormal current can be effectively identified.

[0106] If the difference of a phase is greater than the second threshold, the phase is determined to be an abnormal current phase, indicating that the current of the phase has obvious abnormalities (such as current sensor failure, uneven load, short circuit, etc.). At the same time, if the difference of the remaining N-1 phases is less than or equal to the second threshold, it can be considered that the current changes of these phases are within the normal range, and therefore these phases are determined to be normal current phases.

[0107] The core of this difference determination method is that by comparing the difference between the reference current value and the real-time current value of each phase, the phases with normal current and abnormal current can be effectively distinguished. This method can not only quickly and accurately locate the abnormal current phase, but also detect problems in motor control in a timely manner and take remedial measures, thereby avoiding motor failure or performance degradation caused by abnormal current.

[0108] For ease of understanding, the present application provides a specific embodiment as follows:

[0109] This embodiment takes a three-phase motor as an example. For a five-phase motor, the principle is similar and will not be described in detail in this application.

[0110] Under the premise that there is no short circuit or leakage on the motor and controller, the amount of charge passing through the three phases of the motor per unit time is conserved, which is a basic law. The charge passing through the three phases of the motor can be collected by the three-phase current sensor. The three-phase current collected at the same time is the amount of charge passing through the three phases of the motor per unit time. The sum of the three-phase current is 0, that is, ;

[0111] During PMSM vector control, when the current collecting sensor fails, or impedance interference occurs in the signal transmission line, or the connector is rusted or loose, it is necessary to quickly diagnose and identify the faulty phase and isolate the faulty phase.

[0112] The present invention is carried out in a PMSM synchronous rotating coordinate system, which is connected to a DC and the amount of communication bridge.

[0113] According to Clark transformation, Transform from the three-phase stationary coordinate system to the two-phase stationary coordinate system, such as Figure 2 As shown:

[0114] at this time , (Formula 1);

[0115] Among them, K represents the transformation matrix coefficient. There are two options for K value according to different requirements. When the transformation selects equal power transformation, K value is , which means that the power value remains unchanged before and after the Clark transform. When the equal-amplitude transform is selected, the K value is 2 / 3, which means that the amplitude remains unchanged before and after the Clark transform.

[0116] In vector control, whether the action is in speed loop mode or torque loop mode, the reference of the inner loop is always in the synchronous rotating coordinate system. , you can The synchronously rotating coordinate system is transformed into In the two-phase stationary coordinate system, Figure 3 As shown, Figure 3 middle, The axis coincides with the A axis;

[0117] at this time, , (Formula 2), where Indicates the current angle of the rotor, express The reference current value of phase A in the two-phase stationary coordinate system when the A axis coincides with the A axis.

[0118] Among them, the three-phase Hall current sensor collects the phase current. In the basic Clark transformation, if only , can be obtained in When the axis and the A axis coincide, the real-time current value of phase A in the two-phase stationary coordinate system for: , (Formula 3);

[0119] Also given After the inverse Park transformation, we can get the given Reference current value of phase A of the axis It is expressed as: , (Formula 4);

[0120] According to formula (3) and formula (4), it can be seen that in the synchronous rotating coordinate system, When the A-axis and the A-axis coincide, when a fault occurs in the A-phase will change, so the reference current value of phase A can be given And the real-time current value of phase A analyzed The difference determines whether there is a fault in the A phase current.

[0121] Similarly, according to the traditional coordinate transformation, The axis coincides with the A axis, analogy to The axes coincide with the B axis and the C axis respectively, and the Clark coordinate transformation is performed on the ABC three-phase current. The specific relationship structure diagram is as follows Figure 4 As shown:

[0122] When the A axis coincides with the B axis, the Clark transformation of the real-time three-phase current can be obtained:

[0123] , (Formula 5);

[0124] Where: express The real-time current value of phase B in the two-phase stationary coordinate system when the A-axis coincides with the B-axis.

[0125] When the axis coincides with the B axis, for a given Performing Park transformation yields:

[0126] , (Formula 6);

[0127] Where: express The reference current value of phase B in the two-phase stationary coordinate system when the A-axis coincides with the B-axis.

[0128] When the axis coincides with the C axis, for a given By performing Clark transformation, we can get:

[0129] , (Formula 7);

[0130] Where: express The real-time current value of phase C in the two-phase stationary coordinate system when the A-axis coincides with the C-axis.

[0131] When the A axis coincides with the C axis, Clark transformation is performed on the real-time three-phase current to obtain:

[0132] , (Formula 8);

[0133] Where: express The reference current value of phase C in the two-phase stationary coordinate system when the A axis coincides with the C axis.

[0134] When the axis coincides with the B axis, the sum of the three-phase currents is zero, and the currents of the AB phases are synthesized into the C phase current to make a fault-tolerance judgment on the B phase current. The real-time current value of the B phase in the two-phase stationary coordinate system is obtained according to formula (5). :

[0135] , (Formula 9);

[0136] When the axis coincides with the B axis, the reference current value of phase B in the two-phase stationary coordinate system is obtained by equation (6): :

[0137] , (Formula 10);

[0138] When the axis coincides with the C axis, the sum of the three-phase currents is zero, and the current of the BC phase is used to synthesize the C phase current to make a fault tolerance judgment of the C phase current. According to formula (7), the real-time current value of the C phase analyzed in the two-phase stationary coordinate system is obtained: ,

[0139] , (Formula 11);

[0140] Similarly, When the A axis coincides with the B axis, the given current in the two-phase stationary coordinate system is obtained by formula (8): :

[0141] , (Formula 12);

[0142] According to the calculations in different coordinate systems and By doing the difference, we can get:

[0143] , (Formula 13);

[0144] When the error , , When the error is less than the set allowable threshold (ie, the second threshold), the three-phase current fault-tolerant control is not performed, and the original real-time three-phase current is used for vector calculation.

[0145] In order to further prevent misjudgment, the current fault tolerance control is performed only when the absolute value of the sum of the three-phase currents is greater than a certain value (that is, the first threshold mentioned above). As a prerequisite.

[0146] The three-phase current error phase fast fault-tolerant control structure diagram is as follows: Figure 5 shown.

[0147] When quickly identifying abnormal phase current, the three-phase current and the given The three-phase current is sent to the three-phase current fast diagnosis and fault tolerance unit. First, the Clark transformation in the offset coordinate system is performed on the three-phase currents in pairs. Perform the anti-Park operation in the offset coordinate system. Solve the two coordinate systems. The error between , according to the error The abnormal phase of the three currents is quickly located, where the logic is as follows: Figure 6 and Figure 7 shown.

[0148] Figure 6 middle, is the three-phase current used for vector closed loop, is the real-time three-phase current measured by the Hall current sensor, The error between the real-time current value and the reference current value of the three-phase current in the stationary coordinate system, is the error tolerance threshold (also known as the second threshold).

[0149] Above , The only difference between the ABC three-phase stationary coordinate system and the ABC three-phase stationary coordinate system is the coefficient. , , Can be equivalent to With reference current value , , The reference current value of the three phases , , , can be obtained by a complete inverse Park and inverse Clark transformation of the target current Id and Iq, and the operation structure can be more concise, the logic is as follows Figure 7 shown.

[0150] The target Id and Iq are converted into a two-phase stationary coordinate system by using the offset coordinate system method to obtain three reference current values ​​and compared with the three-phase real-time current values ​​obtained by the measurement and analysis of the three-phase stationary coordinate system, or the target Id and Iq are converted into a three-phase stationary coordinate system by using the direct coordinate transformation method to obtain the three-phase reference current values ​​and compare with the three-phase real-time current values ​​obtained by the measurement and analysis. By comparing the errors between the three-phase reference current values ​​and the three-phase real-time current values, and combining the relationship between the sum of the three-phase real-time current values ​​deviating from 0 and the three errors, the abnormal phase current can be quickly and accurately located. In this embodiment, when an abnormality occurs in the sampling of a certain phase current, the basic characteristic that the sum of the three-phase currents is zero is used to reconstruct the abnormal phase current by synthesizing the remaining two phase currents. The fault tolerance of the controller system can be enhanced. When an abnormality occurs in a phase current sensor, the abnormal phase is identified, and only the currents sampled normally by the other two phases are used for control, ensuring that the motor controller system can continue to output current normally. This strategy effectively addresses the problem of abnormal single-phase current sampling and ensures the integrity of current data.

[0151] To further improve the accuracy of diagnosis, special attention should be paid to the phase current with the largest error, because when the abnormal phase current approaches the zero point, the impact of the abnormal phase error on vector control may be weakened, thereby increasing the risk of misjudgment. In order to avoid misjudgment, the absolute value of the sum of the real-time current values ​​of the three phases obtained after measurement and analysis is increased to help judge whether it is greater than a certain value (that is, the first threshold). When the current sampling value of any phase is abnormal, the sum of the three-phase current measured and analyzed will deviate from 0. Furthermore, only when one of the phase currents has a deviation exceeding the threshold and the other two phases are normal, is the abnormal phase current confirmed and the abnormal phase current synthesis performed. This identification and synthesis method can capture current anomalies more comprehensively, and can accurately identify the problem in the current system even when the abnormal phase current is close to zero.

[0152] Second, as Figure 8 As shown, the present application provides a current anomaly detection device, comprising:

[0153] The acquisition module 81 is used to acquire the real-time N-phase current of the N-phase motor in the current cycle; N≥3, and N is an integer;

[0154] A transformation module 82, used to determine a reference current value corresponding to each phase of the N-phase motor in a preset coordinate system, and / or transform the real-time N-phase current to a preset coordinate system to obtain each corresponding real-time current value; the preset coordinate system is an N-phase stationary coordinate system or a two-phase stationary coordinate system;

[0155] A judgment unit 83, used to determine whether there is an abnormal current phase according to the sum of all real-time current values;

[0156] The positioning unit 84 is used to locate the abnormal current phase and the normal current phase according to the difference between each corresponding reference current value and the real-time current value when there is an abnormal current phase.

[0157] For an introduction to the current anomaly detection device, please refer to the above embodiments, and this application will not go into details here.

[0158] In a third aspect, the present application provides an electronic device, including:

[0159] Memory for storing computer programs;

[0160] The processor is used to implement the steps of the current anomaly detection method as described above when executing the computer program. For the introduction of the electronic device, please refer to the above embodiment, and this application will not repeat it here.

[0161] In a fourth aspect, the present application provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the steps of the current anomaly detection method as described above are implemented. For an introduction to the computer-readable storage medium, please refer to the above embodiment, and the present application will not repeat it here.

[0162] It should also be noted that, in this specification, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprises", "comprising" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the statement "comprising a ..." does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0163] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for detecting abnormal current, characterized in that: include: Get the real-time N-phase current of the N-phase motor in the current cycle; N ≥ 3, and N is an integer; Determine a reference current value corresponding to each phase of the N-phase motor in a preset coordinate system, and / or transform the real-time N-phase current to the preset coordinate system to obtain each corresponding real-time current value; The preset coordinate system is an N-phase stationary coordinate system or a two-phase stationary coordinate system; Determine whether there is an abnormal current phase according to the sum of all the real-time current values; If there is an abnormal current phase, the abnormal current phase and the normal current phase are located according to the difference between each corresponding reference current value and the real-time current value.

2. The current anomaly detection method according to claim 1, characterized in that: After locating the abnormal current phase and the normal current phase according to the difference between each corresponding reference current value and the real-time current value, the method further includes: Calculating the corrected current value of the abnormal current phase according to the real-time current values ​​of all the normal current phases; In the next cycle, the N-phase motor is controlled according to the reference current value, the correction current value and the real-time current value of the normal current phase.

3. The current anomaly detection method according to claim 2, characterized in that: Calculating the corrected current value of the abnormal current phase according to the real-time current values ​​of all the normal current phases includes: Calculating the sum of the real-time current values ​​of all the normal current phases; The sum of the real-time current values ​​of the normal current phase is inverted to obtain the corrected current value of the abnormal current phase.

4. The current anomaly detection method according to claim 1, characterized in that: Determining a reference current value corresponding to each phase of the N-phase motor in a preset coordinate system includes: Obtaining a target current of the N-phase motor in a synchronous rotating coordinate system; Let the two-phase stationary coordinate system The axis coincides with the axis of each phase in the N phases, and an inverse Park transformation is performed on the target current to obtain a reference current value of each corresponding phase in a two-phase stationary coordinate system.

5. The current anomaly detection method according to claim 1, characterized in that: Determining a reference current value corresponding to each phase of the N-phase motor in a preset coordinate system includes: Obtaining a target current of the N-phase motor in a synchronous rotating coordinate system; The target current is subjected to inverse Park transformation and inverse Clark transformation in sequence to obtain each corresponding reference current value in an N-phase stationary coordinate system.

6. The current anomaly detection method according to any one of claims 1 to 5, characterized in that: Determining whether there is an abnormal current phase according to the sum of all the real-time current values ​​includes: Calculating a sum of all the real-time current values, and determining whether an absolute value of the sum is greater than a first threshold; If it is greater than the first threshold, it is determined that the abnormal current phase exists; If it is less than or equal to the first threshold, it is determined that the abnormal current phase does not exist, and in the next cycle, the N-phase motor is controlled according to the reference current value and the real-time N-phase current.

7. The current anomaly detection method according to any one of claims 1 to 5, characterized in that: The method of locating the abnormal current phase and the normal current phase according to the difference between each corresponding reference current value and the real-time current value comprises: Calculating the difference between each corresponding reference current value and the real-time current value; If there is any corresponding difference greater than the second threshold, and the difference of the remaining N-1 phases is less than or equal to the second threshold, the phase whose difference is greater than the second threshold is determined to be the abnormal current phase, and the phase whose difference is less than or equal to the second threshold is determined to be the normal current phase.

8. A current anomaly detection device, characterized in that: include: An acquisition module is used to acquire the real-time N-phase current of the N-phase motor in the current cycle; N ≥ 3, and N is an integer; A transformation module, used to determine a reference current value corresponding to each phase of the N-phase motor in a preset coordinate system, and / or transform the real-time N-phase current to the preset coordinate system to obtain each corresponding real-time current value; The preset coordinate system is an N-phase stationary coordinate system or a two-phase stationary coordinate system; A judgment unit, used for determining whether there is an abnormal current phase according to the sum of all the real-time current values; The positioning unit is used for positioning the abnormal current phase and the normal current phase according to the difference between each corresponding reference current value and the real-time current value when the abnormal current phase exists.

9. An electronic device, characterized in that: include: Memory for storing computer programs; A processor, used to implement the steps of the current anomaly detection method as described in any one of claims 1 to 7 when executing a computer program.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the current anomaly detection method according to any one of claims 1 to 7 are implemented.

Images