Multi-phase motor IGBT open-circuit fault identification method and system and storage medium

Abstract

The invention provides a multi-phase motor IGBT open-circuit fault identification method and system and a storage medium, and relates to the technical field of motor control, and the method comprises the steps: obtaining the actual rotating speed of a multi-phase motor; when the actual rotating speed is larger than a set rotating speed threshold value, a first diagnosis strategy is started, and the first diagnosis strategy is used for conducting harmonic analysis based on all phases of currents of the multi-phase motor to locate a fault phase where an IGBT open-circuit fault occurs; when the actual rotating speed is smaller than a set rotating speed threshold value, a second diagnosis strategy is started, and the second diagnosis strategy is used for positioning a fault phase with an IGBT open-circuit fault based on the duty ratio and the current of each phase of the multi-phase motor; and generating an IGBT open-circuit fault identification result containing the fault phase. According to the method, different diagnosis strategies are dynamically selected according to the rotating speed of the motor, the fault positioning accuracy can be effectively improved, the misdiagnosis situation is avoided, and accurate identification of the IGBT open-circuit fault under all working conditions is achieved.

Description

Technical Field

[0001] This disclosure belongs to the field of motor control technology, specifically relating to a method, system, and storage medium for identifying open-circuit faults in IGBTs of multiphase motors. Background Technology

[0002] IGBT faults in motor drivers are mainly classified into short-circuit faults and open-circuit faults. When an IGBT fault occurs, it is necessary to identify the fault type and location promptly. Short-circuit faults occur for a short time, usually a few microseconds, making them difficult to detect. Therefore, motor drivers incorporate hardware protection circuits such as fast-acting fuses to convert short-circuit faults into open-circuit faults for handling. After an open-circuit fault occurs, the motor driver can continue to operate for a short period. However, if not detected promptly, it may cause increased current and severe overheating in other circuit breakers, potentially leading to secondary faults and significant economic losses.

[0003] In related technologies, research on motor driver fault diagnosis focuses on IGBT open-circuit fault identification.

[0004] Most IGBT open-circuit fault identification methods rely on software monitoring of phase current harmonic content to identify the faulty phase. This type of method has the following drawbacks: First, it only uses the fault characteristics exhibited by harmonic current mapped to a stationary coordinate system, resulting in a narrow application scope. Second, the harmonic content varies significantly under different operating conditions, making it difficult to accurately calibrate the diagnostic threshold and easily leading to misdiagnosis. Furthermore, when the rotational speed is close to zero, the current approaches DC, making it unsuitable for identifying IGBT open-circuit faults through harmonic content. Third, it depends on filter settings, and misdiagnosis may occur when the chip's computing power is insufficient or the filter parameters are improperly set. Summary of the Invention

[0005] This disclosure provides a method, system, and storage medium for identifying IGBT open-circuit faults in multiphase motors, aiming to at least partially solve the technical problem that related technologies cannot accurately identify IGBT open-circuit faults covering all operating conditions.

[0006] At least one embodiment of this disclosure provides a method for identifying open-circuit faults in IGBTs of multiphase motors, applied to a motor driver electrically connected to a multiphase motor, including: Obtain the actual speed of a multiphase motor; When the actual rotational speed is greater than a set rotational speed threshold, a first diagnostic strategy is initiated, wherein the first diagnostic strategy is used to perform harmonic analysis based on the phase current of each phase of the multiphase motor to locate the faulty phase in which the IGBT open circuit fault occurs. When the actual rotational speed is less than a set speed threshold, a second diagnostic strategy is activated. This second diagnostic strategy is used to locate the faulty phase with an IGBT open-circuit fault based on the duty cycle and current of each phase of the multiphase motor. Generate IGBT open-circuit fault identification results that include the faulty phase.

[0007] The above solution offers the following technical advantages: It provides a method for identifying IGBT open-circuit faults in multi-phase motors, particularly six-phase motors. Given that the actual speed variation of a multi-phase motor significantly affects the harmonic plane, dynamically selecting different diagnostic strategies based on the actual speed effectively avoids misdiagnosis, captures fault characteristics more comprehensively, reduces the possibility of missed detections, improves the accuracy of fault location, and effectively enhances the accuracy and coverage of IGBT open-circuit fault identification results, thereby strengthening the overall diagnostic capability of the system. This speed-adaptive diagnostic method not only helps improve the speed of fault identification but also further enhances the accuracy of diagnosis, ensuring that the system can achieve fast and reliable fault detection under various operating conditions.

[0008] In at least one embodiment of the method provided in this disclosure, the first diagnostic strategy is configured as follows: Obtain the current of each phase of the multiphase motor; Determine whether the current of each phase of the multiphase motor meets the preset first constraint condition used to prevent the first diagnostic strategy from mispositioning. When the phase currents of the multiphase motor satisfy the first constraint condition, VSD coordinate transformation is performed on the phase currents of the multiphase motor to obtain the current components of the xy harmonic plane. The total amplitude of the harmonic current is generated based on the current components of the xy harmonic plane; and, When the total amplitude of the harmonic current is greater than the preset fault judgment current threshold, the fault phase is located by matching the current components of the xy harmonic plane with the preset correspondence between the fault phase and the harmonic current trajectory.

[0009] The above solution has the following technical effects: Under high-speed operating conditions, the harmonic characteristics of each phase current are analyzed by coordinate transformation, and the fault phase is accurately located by comparing the total amplitude of the harmonic current with the fault judgment current threshold and combining the preset correspondence between the fault phase and the harmonic current trajectory, such as the characteristics of the harmonic current trajectory when a specific phase is faulty.

[0010] In at least one embodiment of the method provided in this disclosure, determining whether the phase currents of the multiphase motor satisfy a preset first constraint condition for preventing mispositioning by the first diagnostic strategy includes: The absolute values ​​of the current in each phase of the multiphase motor are taken and accumulated to generate the accumulated current value for each phase. The accumulated current values ​​of each phase are sorted to obtain the maximum and minimum accumulated current values; To verify the first constraint condition, it is determined whether the maximum accumulated current value is greater than the product of the minimum accumulated current value and the number of motor phases; and, If the maximum accumulated current value is greater than the product of the minimum accumulated current value and the number of phases of the motor, it is determined that the current of each phase of the multiphase motor satisfies the first constraint condition.

[0011] The above solution has the following technical advantages: it combines the electrical characteristics and fault features of multiphase motors, and can effectively diagnose IGBT open circuit faults in complex operating environments.

[0012] In the method provided in at least one embodiment of this disclosure, the second diagnostic strategy is configured as follows: Obtain the duty cycle of each phase of the multiphase motor; For each target phase of the multiphase motor, determine whether its duty cycle meets the preset second constraint condition used to prevent the second diagnostic strategy from mispositioning; When the duty cycle satisfies the second constraint condition, the actual current of the target phase is obtained; Based on the actual current, identify whether an IGBT open-circuit fault has occurred in the target phase, and generate an IGBT open-circuit fault diagnosis result for the target phase; and, Based on the IGBT open-circuit fault diagnosis results for each target phase, the faulty phase is located.

[0013] The above solution has the following technical effects: under low speed or static conditions, the faulty phase can be identified by monitoring the duty cycle of each phase and the corresponding actual current.

[0014] In at least one embodiment of the method provided in this disclosure, determining whether the duty cycle satisfies a preset second constraint condition for preventing mispositioning of the second diagnostic strategy includes: Determine whether the duty cycle of the target phase is within a set range and the duration of the duty cycle of the target phase being within the set range exceeds a set time, in order to verify the second constraint condition; If so, determine that the duty cycle satisfies the second constraint condition; and, If not, the duty cycle is determined to not satisfy the second constraint condition.

[0015] The above solution has the following technical effect: avoiding misdiagnosis in the second diagnostic process.

[0016] In at least one embodiment of the method provided in this disclosure, the step of identifying whether an IGBT open-circuit fault has occurred in the target phase based on the actual current includes: In response to the actual current being less than a preset current judgment threshold, it is determined that an IGBT open-circuit fault has occurred in the target phase; and, In response to the actual current being greater than or equal to a preset current judgment threshold, it is determined that the target phase has not experienced an IGBT open-circuit fault.

[0017] The above solution has the following technical effect: enabling rapid diagnosis using the second diagnostic strategy.

[0018] The method provided in at least one embodiment of this disclosure further includes: Obtain the voltage of each phase of the multiphase motor; The initial value of the fault judgment current threshold is generated based on the phase voltage of the multiphase motor. Obtain the actual operating parameters of the multiphase motor, wherein the actual operating parameters include actual speed and actual torque; and, The initial value of the fault judgment current threshold is adjusted based on the actual operating parameters to generate the final fault judgment current threshold.

[0019] The above scheme has the following technical effects: considering the influence of speed and torque on harmonics, the calibrated fault threshold is corrected based on speed and torque, reducing the complexity and difficulty of manual calibration.

[0020] The method provided in at least one embodiment of this disclosure further includes: After detecting a hardware drive fault signal in the motor driver, a control command is generated to obtain the actual speed of the multiphase motor, thereby initiating IGBT open circuit fault identification. A fault signal is generated based on the fault phase located by the first or second diagnostic strategy. Verify whether the timing stability of the fault signal meets the set criteria; and, When the timing stability of the fault signal meets the set standard, a control command is issued to generate the IGBT open-circuit fault identification result.

[0021] The above scheme has the following technical effects: by clarifying the credibility of the fault signal and then outputting the IGBT open-circuit fault identification result including the fault phase, it helps to further improve the credibility and effectiveness of the fault identification result.

[0022] At least one embodiment of this disclosure also provides a multiphase motor IGBT open-circuit fault identification system, applied to a motor driver electrically connected to a multiphase motor, comprising: The acquisition unit is configured to acquire the actual speed of the multiphase motor; The first processing unit is configured to activate a first diagnostic strategy when the actual rotational speed is greater than a set rotational speed threshold. The first diagnostic strategy is used to perform harmonic analysis based on the phase current of each phase of the multiphase motor to locate the faulty phase in which the IGBT open circuit fault occurs. The second processing unit is configured to activate a second diagnostic strategy when the actual rotational speed is less than a set rotational speed threshold. This second diagnostic strategy is used to locate the faulty phase experiencing an IGBT open-circuit fault based on the duty cycle and current of each phase of the multi-phase motor. The result generation unit is configured to generate IGBT open-circuit fault identification results containing the faulty phase.

[0023] At least one embodiment of this disclosure also provides a storage medium storing a program or instructions, wherein the program or instructions, when executed by a processor, implement the steps of the method provided in any embodiment of this disclosure.

[0024] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of this disclosure, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 A flowchart illustrating a method for identifying open-circuit faults in IGBTs of multiphase motors, provided for at least one embodiment of this disclosure; Figure 2 A flowchart of a first diagnostic strategy provided for at least one embodiment of this disclosure; Figure 3 A flowchart illustrating the determination scheme for the first constraint provided in at least one embodiment of this disclosure; Figure 4 A flowchart of a second diagnostic strategy provided for at least one embodiment of this disclosure; Figure 5 A flowchart illustrating the second constraint determination scheme provided for at least one embodiment of this disclosure; Figure 6 Flowchart of another method for identifying open-circuit faults in IGBTs of multiphase motors provided in at least one embodiment of this disclosure; Figure 7 A structural block diagram of a multiphase motor IGBT open-circuit fault identification system provided in at least one embodiment of this disclosure; Figure 8A schematic diagram illustrating the composition of a program product provided for at least one embodiment of this disclosure.

[0027] Figure label: 10- Multiphase motor IGBT open circuit fault identification system; 11- Acquisition unit; 12- First processing unit; 13- Second processing unit; 14- Result generation unit; 21- Processor; 22- Memory; 23- Input device; 24- Output device. Detailed Implementation

[0028] The present disclosure will now be described in further detail with reference to the accompanying drawings and embodiments. It should be particularly noted that the following embodiments are for illustrative purposes only and do not limit the scope of the disclosure. Similarly, the following embodiments are only some, not all, embodiments of the present disclosure, and all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0029] The terms "first," "second," and "third" used in the embodiments of this disclosure are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first," "second," and "third" may explicitly or implicitly include at least one of that feature.

[0030] In the description of this disclosure, "multiple" means at least two, such as two or three, unless otherwise expressly and specifically limited.

[0031] In this disclosure, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of this disclosure. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0032] The terms “comprising” and “having”, and any variations thereof, used in this disclosure are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the steps or units listed, but may optionally include steps or units not listed, or may optionally include other steps or components inherent to such processes, methods, products, or devices.

[0033] In this disclosure, the term "IGBT" refers to an electronic switch in an automotive motor controller. Its core function is to efficiently control the transmission and switching of electrical energy in the motor. It drives the motor by quickly switching DC power to AC power and adjusting the voltage / frequency to achieve precise control of speed and torque.

[0034] The term "VSD coordinate transformation" in this disclosure is a commonly used coordinate transformation method in the control of dual three-phase motors. By transforming the motor winding current / voltage from the three-phase stationary coordinate system to the two-phase rotating coordinate system, i.e., the dq coordinate system, the decoupled control of the magnetic field and torque is achieved, simplifying the calculation of complex AC variables and improving control accuracy and dynamic response.

[0035] The term "hardware driver fault signal" in the embodiments of this disclosure is also referred to as hardware IGBT fault signal or driver transistor hardware conduction signal.

[0036] The principles involved in this disclosed method will be introduced first below.

[0037] When an IGBT fault occurs, the state of the hardware drive fault signal will usually change. After the collected hardware drive fault signal is set, in order to avoid misdiagnosis, further identification of the first and second diagnostic strategies is required to diagnose the specific fault phase.

[0038] When no hardware driver fault signal is detected or there is no hardware driver fault signal, the first and second diagnostic strategies can be used to further identify the specific fault phase based on the actual operating conditions.

[0039] When the actual speed exceeds the set speed threshold and an IGBT in the motor driver experiences an open-circuit fault, the phase current of one phase will become abnormal. In the xy harmonic plane based on VSD coordinate transformation, the harmonic voltage will change significantly, thereby affecting the current components and the total amplitude of the harmonic current (also known as the total harmonic current amplitude) in the xy harmonic plane. Based on this, a first diagnostic strategy is designed to perform harmonic analysis on the phase currents of the multi-phase motor when the actual speed exceeds the set speed threshold, in order to locate the faulty phase with the IGBT open-circuit fault.

[0040] When the actual speed is less than the set speed threshold and an IGBT in the motor driver experiences an open-circuit fault, the motor current approaches DC, making it impossible to identify the faulty phase based on harmonic current and the current characteristics of each phase. Therefore, a different diagnostic strategy is needed. Based on this, a second diagnostic strategy was designed, which detects the duty cycle of each phase and the actual current of the corresponding phase in the software to locate the faulty phase with the IGBT open-circuit fault.

[0041] Figure 1This is a flowchart illustrating a method for identifying open-circuit faults in IGBTs of multiphase motors, provided in at least one embodiment of this disclosure. This method can be applied to a motor driver electrically connected to a multiphase motor, wherein the multiphase motor is, but is not limited to, a six-phase motor. The motor driver includes IGBTs corresponding to each phase winding of the multiphase motor. Figure 1 As shown, the method may include the following steps S10-S50.

[0042] Step S10: Obtain the actual speed of the multiphase motor.

[0043] Step S20: When the actual speed is greater than the set speed threshold (high speed condition), the first diagnostic strategy is activated. The first diagnostic strategy is used to locate the faulty phase with IGBT open circuit fault based on harmonic analysis of the phase current of each phase of the multiphase motor.

[0044] Step S30: When the actual speed is less than the set speed threshold (low speed condition or stationary condition), the second diagnostic strategy is activated. The second diagnostic strategy is used to locate the faulty phase of IGBT open circuit fault based on the duty cycle of each phase of the multiphase motor and the current of each phase.

[0045] Step S40: Generate IGBT open-circuit fault identification results containing the faulty phase.

[0046] During implementation, the actual speed of the multiphase motor is obtained through step S10 to select a diagnostic strategy. At high speed, the first diagnostic strategy in step S20 is used for fault identification. At low speed or no speed, the second diagnostic strategy in step S30 is used for fault identification. When the faulty phase is located, the IGBT open circuit fault identification result containing the faulty phase is generated through step S40.

[0047] In the above scheme, this disclosure does not limit the method for obtaining the actual speed of the multiphase motor in step S10. In practical applications, the actual speed of the multiphase motor can be obtained in various ways. For example, a common method is to use a speed sensor, such as an encoder. The encoder can be installed on the motor shaft. As the motor rotates, the encoder outputs pulse signals related to the speed. By counting and processing these pulse signals, the actual speed of the multiphase motor can be accurately calculated. This method has high accuracy and reliability and can meet the needs of most application scenarios. Another method is to use a sensorless speed estimation method. This method does not require the installation of an additional speed sensor. Instead, it estimates the actual speed of the motor by measuring and analyzing the electrical parameters of the motor, such as voltage and current, and using the mathematical model of the motor. The sensorless speed estimation method has advantages such as low cost and convenient installation.

[0048] When executing step S10, the system may need to select an appropriate speed acquisition method based on the specific application scenario and requirements. Simultaneously, factors such as cost, accuracy, and reliability must be considered to ensure the system can operate stably and efficiently.

[0049] In the above scheme, this disclosure does not limit the specific content of how the first diagnostic strategy in step S20 locates the faulty phase of the IGBT open circuit fault based on harmonic analysis of the phase currents of the multiphase motor. In practical application scenarios, in addition to the schemes described in the following embodiments, there are many other feasible technical paths. For example, advanced signal processing algorithms can be used to deeply mine the phase currents. Through wavelet transform algorithms, the current signal is decomposed into different scales to find the harmonic feature information contained therein. Different faulty phases will have different feature manifestations after wavelet transform. By accurately identifying these features, the faulty phase of the IGBT open circuit fault can be located. As another example, machine learning models can be used to locate the faulty phase. A large amount of phase current data is collected under normal operation and different fault conditions. This data is used to train a classification model, such as a support vector machine model. After training, the model can learn the current pattern features of different faulty phases. When a suspected IGBT open circuit fault occurs in actual operation, the real-time collected phase currents are input into the trained model, and the model can accurately determine the specific faulty phase based on its learned knowledge. For example, fuzzy logic theory can be used for fault location. By analyzing the harmonic content in each phase current and the relationships between them, a series of fuzzy rules can be established. For instance, if the content of a specific harmonic in a phase current exceeds a certain threshold and its correlation coefficient with other phase currents deviates from the normal range, the phase can be determined as faulty based on the established fuzzy rules. This can reduce the impact of measurement errors and interference on fault location to a certain extent, improving the accuracy and robustness of the location.

[0050] When the system executes step S20, it may need to select an appropriate first diagnostic strategy based on the specific application scenario and requirements.

[0051] In the above scheme, this disclosure does not limit how the second diagnostic strategy in step S30 locates the faulty phase of the IGBT open-circuit fault based on the duty cycle and current of each phase of the multiphase motor. In practical application scenarios, in addition to the scheme described in the following embodiments, there are many other feasible technical paths. For example, a data-driven deep learning method can also be used to achieve this fault location. A deep neural network model can be constructed, using the duty cycle and current of each phase of the multiphase motor as input features. During the training phase, a large amount of data on the duty cycle and current of each phase under different operating conditions and during IGBT open-circuit faults is collected, and the faulty phase is labeled. This data is used to train the deep neural network, allowing the model to learn the mapping relationship between the input features and the faulty phase under different fault conditions. When fault location is required during motor operation, the real-time collected duty cycle and current of each phase are input into the trained deep neural network model, and the model will output the possible faulty phase based on the learned mapping relationship. This method can fully extract potential information from the data and has strong adaptability and generalization ability. Even in the face of complex operating conditions and interference, it can accurately locate the faulty phase. For example, fault location can also be combined with an expert system. Relevant knowledge and experience regarding IGBT open-circuit faults in multi-phase motors, such as the faulty phase conditions corresponding to different duty cycles and current characteristics, can be stored in the expert system's knowledge base in the form of rules. After acquiring the duty cycle and current data for each phase, the expert system will match this data with the rules in the knowledge base and determine the possible faulty phase through a reasoning mechanism.

[0052] When the system executes step S30, it may need to select an appropriate second diagnostic strategy based on the specific application scenario and requirements.

[0053] Steps S10-S40 provide a method for identifying IGBT open-circuit faults in multi-phase motors, particularly six-phase motors. Given that the actual speed variation of a multi-phase motor significantly affects harmonics, dynamically selecting different diagnostic strategies based on the actual speed effectively avoids misdiagnosis, captures fault characteristics more comprehensively, reduces the possibility of missed detections, and improves the accuracy of fault location. This significantly enhances the accuracy and coverage of IGBT open-circuit fault identification results, thereby strengthening the overall diagnostic capability of the system. This speed-adaptive diagnostic method not only helps improve the speed of fault identification but also further enhances the accuracy of diagnosis, ensuring that the system can achieve fast and reliable fault detection under various operating conditions.

[0054] Some embodiments of this disclosure also provide systems, storage media, and program products corresponding to the methods described above.

[0055] The method provided in at least one embodiment of this disclosure is applicable to any existing multiphase motor application scenario. For example, in the drive system of new energy vehicles, multiphase motors are widely used due to their high power density and fault-tolerant operation capabilities. This method can accurately identify open-circuit faults in IGBTs in the drive system, ensuring the stability of vehicle power output. In the field of industrial servo systems, multiphase motors are commonly used in high-precision CNC machine tools, robot joint drives, and other equipment. This method can monitor the IGBT status in real time, avoiding production interruptions or equipment damage caused by faults. In the aerospace field, multiphase motors are used to drive key components such as the actuation system of multi-electric aircraft and satellite attitude control devices. This fault identification method can improve the reliability of the system and meet stringent aerospace safety standards. Whether under high-speed operation or low-speed heavy-load conditions, this method can achieve rapid response and accurate location of IGBT open-circuit faults based on the actual operating characteristics of the multiphase motor and combined with a speed adaptive diagnostic strategy, providing stable and reliable fault diagnosis support for multiphase motor systems in different application scenarios.

[0056] In some embodiments, in order to improve diagnostic accuracy, Figure 1 Based on this, the speed threshold set in steps S20 and S30 can be set based on the electrical frequency and the number of pole pairs of the multiphase motor, so as to better select the fault diagnosis strategy according to the actual speed of the multiphase motor. The electrical frequency should at least ensure that the sampled values ​​used for logical judgment can cover one electrical frequency cycle within a certain period of time. If the speed threshold is set too low, it will be detrimental to logical judgment.

[0057] As a preferred embodiment, the electrical frequency of the multiphase motor is set. f The ratio of a certain number of sampled values ​​to the sampling frequency should be greater than or equal to a certain number. A certain number of sampled values ​​is typically set to 2000, but this can be adjusted based on experience. f =50-100Hz, set the speed threshold n spd It can be obtained using the following formula: n spd =60× f / N p In the formula, N p This indicates the number of pole pairs of the motor.

[0058] Figure 2 A flowchart illustrating a first diagnostic strategy provided for at least one embodiment of this disclosure. Figure 1 Based on this, in order to ensure accurate location of the faulty phase of a multiphase motor at high speeds, such as... Figure 2As shown, the first diagnostic strategy is configured to include the following sub-steps S201-S205.

[0059] Sub-step S201: Obtain the current of each phase of the multiphase motor.

[0060] Sub-step S202: Determine whether the current of each phase of the multiphase motor meets the preset first constraint condition used to prevent the first diagnostic strategy from mispositioning.

[0061] Sub-step S203: When the phase currents of the multiphase motor meet the first constraint condition, perform VSD coordinate transformation on the phase currents of the multiphase motor to obtain the current components of the xy harmonic plane.

[0062] Sub-step S204: Generate the total amplitude of harmonic current based on the current components of the xy harmonic plane.

[0063] Sub-step S205: When the total amplitude of the harmonic current is greater than the preset fault judgment current threshold (also known as the normal threshold), the fault phase is located by matching the current components of the xy harmonic plane with the preset correspondence between the fault phase and the harmonic current trajectory.

[0064] It should be noted that when the total amplitude of the harmonic current is not greater than the preset fault judgment current threshold, the fault phase is not located, and the process can return to continue executing step S201 or step S203.

[0065] Sub-steps S201-S205 effectively locate and diagnose faulty phases in multi-phase motors operating at high speeds. By acquiring the current of each phase and determining whether it meets the first constraint condition, misdiagnosis under normal current fluctuations can be avoided. Performing a VSD coordinate transformation on the currents that meet the condition, converting them to the xy harmonic plane, allows for clearer analysis of the harmonic components in the current. The total amplitude of the generated harmonic current is a crucial indicator for determining whether a motor fault exists; when this amplitude exceeds the fault diagnosis current threshold, a potential motor fault is indicated. At this point, by matching the current of each phase with the preset correspondence between the faulty phase and the harmonic current trajectory, the faulty phase can be accurately located. This diagnostic strategy, through scientific and reasonable analysis steps, improves the accuracy and reliability of fault diagnosis, providing strong support for IGBT open-circuit diagnosis in multi-phase motors operating at high speeds.

[0066] Under high-speed operating conditions, the above scheme uses coordinate transformation to analyze the harmonic characteristics of each phase current, compares the total amplitude of the harmonic current with the fault judgment current threshold, and combines the preset correspondence between the fault phase and the harmonic current trajectory, such as the characteristics of the harmonic current trajectory when a specific phase is faulty, to accurately locate the fault phase.

[0067] In some embodiments, Figure 2In order to improve the accuracy and coverage of fault diagnosis, the first diagnostic strategy also includes the following sub-step S206.

[0068] Sub-step S206: When the phase current of the multiphase motor does not meet the first constraint condition, obtain the phase current of the multiphase motor again and perform the judgment of the first constraint condition.

[0069] The purpose of acquiring the current of each phase again and making the first constraint condition judgment is to accurately determine the diagnosis time. In this way, the diagnosis range is continuously narrowed, the accuracy and coverage of fault diagnosis are improved, and a more solid guarantee is provided for the stable operation of multiphase motors. It can also detect potential fault hazards in a timely manner, avoid the fault from further expanding and causing serious damage to the motor, reduce maintenance costs and downtime, and improve the operating efficiency and reliability of the entire power system.

[0070] Figure 3 A flowchart illustrating a first constraint determination scheme provided for at least one embodiment of this disclosure. Figure 2 Based on this, in order to avoid misdiagnosis, such as Figure 3 As shown, sub-step S202 is refined to include the following sub-steps S202a-S202d.

[0071] Sub-step S202a: Take the absolute value of each phase current of the multiphase motor and accumulate it to generate the accumulated current value of each phase.

[0072] Sub-step S202b: Sort the accumulated current values ​​of each phase and obtain the maximum and minimum accumulated current values.

[0073] Sub-step S202c: Determine whether the maximum accumulated current value is greater than the product of the minimum accumulated current value and the number of motor phases to verify the first constraint condition.

[0074] Sub-step S202d: If the maximum accumulated current value is greater than the product of the minimum accumulated current value and the number of phases of the motor, it is determined that the current of each phase of the multiphase motor satisfies the first constraint condition.

[0075] The design of sub-steps S202a-S202d is based on the differences in the current characteristics of each phase of a multiphase motor under normal operation and IGBT open-circuit fault conditions. Under normal operation, the currents of each phase are relatively balanced, and the differences between the accumulated current values ​​of each phase are not too large. However, when an IGBT open-circuit fault occurs, the current of the faulty phase becomes abnormal, causing a change in the distribution of the accumulated current values ​​of each phase. By taking the absolute value of each phase current and summing them, the influence of current direction can be eliminated, more accurately reflecting the magnitude of each phase current. The sorting operation highlights the maximum and minimum values ​​of the accumulated current values ​​of each phase, facilitating subsequent comparison and judgment. When the maximum accumulated current value is greater than the product of the minimum accumulated current value and the number of phases of the motor, it indicates a significant imbalance in the distribution of currents in each phase, which is likely caused by an IGBT open-circuit fault. Therefore, it is determined that the currents of each phase of the multiphase motor satisfy the first constraint condition. This judgment method utilizes the characteristics of the currents of each phase under fault conditions, enabling relatively accurate identification of fault conditions. If the maximum accumulated current value is not greater than the product of the minimum accumulated current value and the number of phases of the motor, it is determined that the phase current of the multiphase motor does not meet the first constraint condition. At this time, the difference in harmonic current is not obvious. In this case, it is necessary to obtain the phase current of the multiphase motor again according to the requirements of sub-step S206, and re-execute the judgment of the first constraint condition to further improve the accuracy of fault diagnosis.

[0076] The above solution combines the electrical characteristics and fault features of multiphase motors, and can effectively diagnose IGBT open circuit faults in complex operating environments, providing important support for the reliable operation of multiphase motors.

[0077] As an exemplary implementation, the second diagnostic strategy can be configured as follows: 1) For the current in each phase i A , i B , i C , i U , i V and i W Take the absolute value and sum them up to obtain the cumulative current value ∑| for each phase. i A |、∑| i B |、∑| i C |、∑| i U |、∑| i V | and ∑| i W |; 2) Record the accumulated current values ​​of each phase in ascending order as follows: i 1. i 2. i 3. i 4. i 5 and i 6; 3) When i Once 6 reaches a certain threshold (indicating multiple accumulations), it is then determined whether 6× exists. i 1 < i 6. If it exists, obtain the total amplitude of the harmonic current in the xy harmonic plane. I xy ,judge I xy Does it exceed the fault diagnosis current threshold? I xy =sqrt( i x 2 + i y 2 ), i x This represents the x-axis current in the xy harmonic plane during VSD coordinate transformation. i y This represents the y-axis current in the xy harmonic plane during VSD coordinate transformation; 4) If I xy If the fault current threshold is exceeded, the current is determined based on the preset correspondence between the fault phase and the harmonic current trajectory. i x and i y Which phase of the IGBT has an open circuit fault?

[0078] Different faults correspond to different harmonic current trajectories. The specific IGBT open-circuit fault can be identified by referring to the xy current behavior shown in Table 1 below.

[0079] Table 1 Correspondence between fault phase and harmonic current trajectory

[0080] In Table 1, i AB_err This indicates the line current error between phases A and B caused by an open-circuit fault in the IGBT of phase A or phase B. i BC_err This indicates the line current error between phases B and C caused by an open-circuit fault in the IGBT of phase B or C. i UV_err This indicates the line current error between phases U and V caused by an open-circuit fault in the U-phase or V-phase IGBT.i UW_err This indicates the line current error between phases U and W caused by an open-circuit fault in the U-phase or W-phase IGBT.

[0081] Figure 4 A flowchart illustrating a second diagnostic strategy provided for at least one embodiment of this disclosure. Figure 1 , Figure 2 or Figure 3 Based on this, in order to ensure accurate location of the faulty phase of a multiphase motor under low-speed or stationary conditions, such as Figure 4 As shown, the second diagnostic strategy is configured to include the following sub-steps S301-S305.

[0082] Sub-step S301: Obtain the duty cycle of each phase of the multiphase motor.

[0083] Sub-step S302: For each target phase of the multiphase motor, determine whether its duty cycle meets the preset second constraint condition used to prevent the second diagnostic strategy from mispositioning.

[0084] Sub-step S303: When its duty cycle satisfies the second constraint condition, obtain the actual current of the target phase.

[0085] Sub-step S304: Based on the actual current, diagnose whether an IGBT open-circuit fault has occurred in the target phase, and generate the IGBT open-circuit fault diagnosis result for the target phase.

[0086] Sub-step S305: Based on the IGBT open-circuit fault diagnosis results for each target phase, locate the faulty phase.

[0087] Sub-steps S301-S305 effectively locate and diagnose faulty phases in multi-phase motors under low-speed or precise conditions. To ensure the accuracy and reliability of fault diagnosis, the second constraint condition must be set considering the operating characteristics of the multi-phase motor to avoid misjudgments triggered by duty cycle fluctuations during normal motor operation. When acquiring the actual current of the target phase, a high-precision current sensor can be used for real-time sampling, and the sampled data can be processed by a filtering algorithm to eliminate noise interference and ensure the authenticity of the current signal. When identifying IGBT open-circuit faults based on actual current, in addition to the solutions provided in later embodiments, a current model of the target phase can be constructed, and the actual current can be compared with the model's predicted current. If the deviation between the two exceeds a preset threshold, the target phase is determined to have an IGBT open-circuit fault. Furthermore, after generating the IGBT open-circuit fault diagnosis result, a multi-dimensional verification mechanism can be introduced, such as combining historical fault data or temperature monitoring information of the target phase, to further verify the accuracy of the fault identification result, thereby improving the accuracy of fault phase location and providing strong support for the safe and stable operation of multi-phase motors.

[0088] The above solution improves the accuracy of fault identification by monitoring the duty cycle of each phase and the corresponding actual current when operating at low speed or at a standstill.

[0089] In some embodiments, Figure 4 In order to improve the accuracy and coverage of fault diagnosis, the second diagnostic strategy also includes the following sub-step S306.

[0090] Sub-step S306: When its duty cycle does not meet the second constraint condition, obtain the duty cycle of each phase of the multiphase motor again, and perform the judgment of the second constraint condition.

[0091] The purpose of obtaining the duty cycle of each phase again and making a second constraint judgment is to accurately determine the diagnosis time. In this way, the diagnosis range is continuously narrowed, the accuracy and coverage of fault diagnosis are improved, a more solid guarantee is provided for the stable operation of multiphase motors, potential fault hazards can be detected in time, the fault can be prevented from further expanding and causing serious damage to the motor, maintenance costs and downtime are reduced, and the operating efficiency and reliability of the entire power system are improved.

[0092] Figure 5 A flowchart illustrating the determination scheme for the second constraint provided in at least one embodiment of this disclosure. Figure 4 Based on this, in order to avoid misdiagnosis, such as Figure 5 As shown, sub-step S302 is refined to include the following sub-steps S302a-S302c.

[0093] Sub-step S302a: Determine whether the duty cycle of the target phase is within the set range and the duration of the duty cycle of the target phase being within the set range exceeds the set time, in order to verify the second constraint condition.

[0094] Sub-step S302b: If so, determine that its duty cycle satisfies the second constraint condition.

[0095] Sub-step S302c: If not, determine that its duty cycle does not meet the second constraint condition.

[0096] The set range is determined based on the rated operating parameters of the multiphase motor and historical fault data. Its upper and lower limits must effectively distinguish between normal operating fluctuations and potential fault states. The set time must cover a complete operating cycle of the motor to avoid misjudgments caused by instantaneous interference. By combining the numerical range of the duty cycle with the duration for dual verification, abnormal signs before a fault can be captured more accurately, providing a more reliable basis for subsequent fault diagnosis, further reducing the probability of misdiagnosis, and ensuring the effectiveness and stability of fault identification results.

[0097] As a preferred implementation, to further improve identification accuracy, in sub-step S302a, the duty cycle of the target phase is configured such that the absolute deviation between its duty cycle and the neutral point reference value is greater than the difference between the neutral point reference value and a deviation threshold set based on the system dead time. This deviation threshold comprehensively considers the impact of the system dead time on the duty cycle output. This approach allows for a more precise definition of abnormal fluctuations in the duty cycle, preventing normal deviations caused by inherent system factors such as dead time from being misjudged as fault symptoms. This further improves the accuracy and reliability of the second constraint condition judgment, laying a more solid foundation for subsequent fault identification work.

[0098] In some embodiments, in order to achieve rapid diagnosis using the second diagnostic strategy, sub-step S304 is refined to include sub-step S304a and sub-step S304b.

[0099] Sub-step S304a: In response to the actual current being less than the preset current judgment threshold, determine that the target phase has an IGBT open circuit fault.

[0100] Sub-step S304b: In response to the actual current being greater than or equal to the preset current judgment threshold, determine that no IGBT open circuit fault has occurred in the target phase.

[0101] The current judgment threshold can be obtained through calibration. Current data under different fault conditions can be collected through offline experiments, and the current judgment threshold can be determined using statistical methods to ensure accurate identification of IGBT open-circuit faults even in complex scenarios.

[0102] As one implementation method, the second diagnostic strategy is configured as follows: 1) Detect the duty cycle of each phase in the software separately; 2) When the duty cycle of a certain phase satisfies 0.5-|Duty-0.5|<duty judgment threshold and maintains this state for multiple cycles, the actual current of the corresponding phase is detected at this time. The duty cycle judgment threshold is a calibration value selected based on the actual dead time. Multiple cycles can be 5 consecutive cycles. 3) When the absolute value of the actual current is less than the current judgment threshold, it is determined that an IGBT open circuit fault has occurred in that phase.

[0103] The formula 0.5 - |Duty - 0.5| < duty cycle threshold indicates that no control is performed at zero voltage. For example, when the current loop PI is reset, the output duty cycle of the corresponding phase is 0.5, so 0.5 is selected as the calculation reference value. When the actual duty cycle (Duty) of a certain phase is not near 0.5, but approaches 0 or 1, this indicates that there is a large deviation between the actual current and the required current of that phase. Adjusting the current loop PI will output a larger voltage, which, through a larger duty cycle, should theoretically generate a larger actual current. However, if the absolute value of the actual current of the corresponding phase is less than the current threshold, meaning that the corresponding phase has virtually no current output, it indicates that an IGBT open-circuit fault has occurred in that phase. An open circuit is equivalent to a phase loss.

[0104] In the above scheme, the duty cycle judgment threshold can be set with reference to the dead time and carrier period. For example, with a carrier frequency of 10kHz, a carrier period of 100μs, and a dead time of 5μs, without additional processing, the duty cycle could theoretically have a maximum error of 5μs / 100μs = 5%. To avoid misjudgment, a value slightly larger than 5% can be chosen as the judgment threshold. Based on experience, 10%, or 0.1%, can be chosen as the duty cycle judgment threshold.

[0105] In the above scheme, the current judgment threshold can be set with reference to the sampling error of the current sensor under zero current. For example, the sampling error of the 600A sensor itself is 20mV, and according to the coefficient conversion relationship, 1mV corresponds to 0.3A current value. Therefore, 20mV×0.3A / mV=6A. In order to avoid misdiagnosis, the current judgment threshold should be set to be greater than 6A. The current judgment threshold can be selected as 10A.

[0106] In some embodiments, Figures 1-5 In order to improve the coverage of fault diagnosis, the method may further include the following step S31.

[0107] Step S31: When the actual rotational speed equals the set rotational speed threshold, activate the second diagnostic strategy.

[0108] Step S31 can be placed before or after step 30. Step S31 allows for supplementary judgment of the fault status when the motor is operating at a specific speed, complementing the original diagnostic logic of step S30, further broadening the coverage of fault diagnosis and improving the adaptability of the overall identification method to complex operating conditions.

[0109] Figure 6 A flowchart illustrating another method for identifying open-circuit faults in IGBTs of multiphase motors, provided for at least one embodiment of this disclosure. Figure 2 Based on this, in order to further ensure accurate location of faulty phases in multi-phase motors at high speeds, such as... Figure 6As shown, the method further includes the following steps S11-S14 to correct the fault judgment current threshold in sub-step S205.

[0110] Step S11: Obtain the voltage of each phase of the multiphase motor.

[0111] Step S12: Generate the initial value of the fault judgment current threshold based on the phase voltage of the multiphase motor.

[0112] Step S13: Obtain the actual operating parameters of the multiphase motor, including the actual speed and actual torque.

[0113] Step S14: Adjust the initial value of the fault judgment current threshold based on the actual operating parameters to generate the final fault judgment current threshold.

[0114] Steps S11-S14 can be placed before step S20 or before sub-step 205. Real-time acquisition of phase voltage signals provides fundamental electrical parameters for generating the subsequent current threshold. These parameters directly reflect the voltage fluctuations of the motor under different operating conditions and are crucial for ensuring the accuracy of threshold calculation. When generating the initial value of the fault judgment current threshold, a preset algorithm model can be used to convert the phase voltage data into the initial value. This initial value will adjust accordingly with dynamic voltage changes. The actual operating parameters, such as speed and torque, are key indicators of motor load and operating conditions, and have a significant impact on the current threshold. For example, when the speed increases, the motor back electromotive force increases, and the required current changes accordingly. Therefore, the initial threshold needs to be dynamically corrected based on the torque to avoid deviations in threshold setting due to changes in operating conditions. The resulting fault judgment current threshold better reflects the real-time operating characteristics of the motor, effectively improving the accuracy of fault phase location under high-speed conditions.

[0115] The above scheme takes into account the influence of different speed and torque conditions on the harmonic plane, and can correct the initial value of the fault judgment current threshold based on the mathematical model, thereby reducing the calibration difficulty.

[0116] In some embodiments, Figure 6 Based on this, in order to further improve the diagnostic accuracy, step S12 can be further refined into sub-steps S121-S123.

[0117] Sub-step 121: Perform coordinate transformation on the phase voltages of the multiphase motor to obtain the x-axis voltage components of the xy harmonic plane. u x and y-axis voltage components u y .

[0118] Among them, the x-axis voltage component of the xy harmonic plane ux and y-axis voltage components u y The following relationship must be satisfied:

[0119]

[0120] In the formula, u AB This represents the line voltage between phases A and B. u BC This represents the line voltage between phases B and C. u UV This represents the line voltage between the UV phases. u VW This represents the line voltage between phases V and W.

[0121] Sub-step 122: Based on the voltage law, the xy plane harmonic voltage trajectory corresponding to different faults can be obtained, and then the correspondence between each fault phase and the xy harmonic voltage trajectory can be obtained, thus obtaining the IGBT open circuit fault voltage.

[0122] The correspondence between the fault phase and the xy harmonic voltage trajectory is shown in Table 2.

[0123] Table 2 Correspondence between fault phase and xy harmonic voltage trajectory

[0124] In Table 1, u AB_err This indicates the line voltage error between phases A and B caused by an open-circuit fault in the IGBT of phase A or phase B. u BC_err This indicates the line voltage error between phases B and C caused by an open-circuit fault in the IGBT of phase B or C. u UV_err This indicates the line voltage error between phases U and V caused by an open-circuit fault in the U-phase or V-phase IGBT. u UW_err This indicates the line voltage error between phases U and W caused by an open-circuit fault in the U-phase or W-phase IGBT.

[0125] For example, when an IGBT open-circuit fault occurs in phase W, it will cause the y-axis voltage to... u y The system generates significant outliers but has almost no impact on the x-axis. Based on the voltage equation of the VSD transformed coordinates, it can be concluded that when an IGBT open-circuit fault occurs in phase W, the current trajectory in the xy-plane is a straight line along the y-axis, from which the IGBT open-circuit fault voltage can be obtained. u y =1 / 6× u UW_err .

[0126] Sub-step 123: Based on the IGBT open-circuit fault voltage and phase resistance, the fault current threshold can be obtained and used as the initial value of the fault judgment current threshold.

[0127] The fault current threshold can be calculated based on the IGBT open-circuit fault voltage and phase resistance listed in Table 2. This threshold can be used as the initial value for fault judgment current. Using this calculation method can reduce the difficulty of calibration. By combining the above table with the current performance detected by the software, it can be determined which phase has experienced an IGBT open-circuit fault.

[0128] In some embodiments, Figures 1-5 In order to improve diagnostic accuracy, the method may further include the following step S01.

[0129] Step S01: After detecting a hardware drive fault signal of the motor driver, a control command is generated to obtain the actual speed of the multiphase motor in order to start IGBT open circuit fault identification.

[0130] It should be noted that the hardware driver fault signal can be a fault flag signal reported by the motor driver, which is a high or low level form of 0 or 1. When the motor driver experiences an IGBT module fault, such as a burnt-out open circuit, a high-voltage side detection will be performed, and if a fault is found, a hardware driver fault signal will be reported.

[0131] Introducing hardware-driven fault signals into the software diagnostic process can effectively improve the accuracy and coverage of IGBT open-circuit fault identification results, thereby enhancing the overall diagnostic capability of the system. Through feedback from hardware-driven fault signals, the software diagnostic module can more comprehensively capture fault characteristics, reduce the possibility of missed detections, and improve the accuracy of fault location.

[0132] In some embodiments, Figures 1-6 In order to improve diagnostic accuracy, the method further includes the following steps S50 and S60.

[0133] Step S50: Verify the matching between the fault phase obtained through the first diagnostic strategy or the second diagnostic strategy and the hardware drive fault signal.

[0134] Step S60: When the faulty phase matches the hardware drive fault signal, output the IGBT open circuit fault identification result containing the faulty phase.

[0135] Steps S50 and S60 can be placed after step S40. Hardware-driven fault signals are typically generated in real-time by the motor controller's hardware protection circuit, such as signals triggered by overcurrent protection, overvoltage protection, or temperature protection. By verifying the matching between the faulty phase diagnosed at the software level and the hardware-driven fault signal, the risk of misjudgment due to a single diagnostic strategy can be effectively avoided, improving the reliability of fault identification. When the two match, the accuracy of the faulty phase can be confirmed. At this point, the IGBT open-circuit fault identification result containing specific faulty phase information is output, enabling the subsequent system to quickly take corresponding protection measures or fault handling mechanisms to ensure the safe and stable operation of the multi-phase motor.

[0136] In some embodiments, Figures 1-6 In order to improve diagnostic accuracy, this method also includes coefficient steps S32-S34.

[0137] Step S32: Generate a fault signal based on the fault phase obtained by the first diagnostic strategy or the second diagnostic strategy.

[0138] Step S33: Verify whether the timing stability of the fault signal meets the set standard.

[0139] Step S34: When the timing stability of the fault signal meets the set standard (verification passed), a control command is issued to generate the IGBT open circuit fault identification result.

[0140] The aforementioned scheme, by clarifying the reliability of the fault signal and then outputting the IGBT open-circuit fault identification result including the faulty phase, helps to further improve the reliability and effectiveness of the fault identification result. Especially under the complex operating conditions of multiphase motors, by verifying the stability of the fault signal in the time dimension, false fault signals caused by transient interference or measurement noise can be filtered out, ensuring that the final output fault information can accurately reflect the true IGBT open-circuit fault state, providing a more reliable basis for subsequent protection control and system decision-making.

[0141] Figure 7 This is a structural block diagram of a multiphase motor IGBT open-circuit fault identification system provided in at least one embodiment of this disclosure. The method can be applied to a motor driver electrically connected to a multiphase motor, wherein the multiphase motor is not limited to a six-phase motor. The motor driver is equipped with an IGBT corresponding to each phase winding of the multiphase motor. Figure 7 As shown, the multiphase motor IGBT open circuit fault identification system 10 includes an acquisition unit 11, a first processing unit 12, a second processing unit 13, and a result generation unit 14.

[0142] Acquisition unit 11 is configured to acquire the actual speed of the multiphase motor.

[0143] The first processing unit 12 is configured to activate a first diagnostic strategy when the actual rotational speed is greater than a set rotational speed threshold. The first diagnostic strategy is used to locate the faulty phase of the IGBT open circuit fault based on harmonic analysis of the phase currents of the multiphase motor.

[0144] The second processing unit 13 is configured to activate a second diagnostic strategy when the actual speed is less than a set speed threshold. The second diagnostic strategy is used to locate the faulty phase with an IGBT open circuit fault based on the duty cycle and current of each phase of the multiphase motor.

[0145] The result generation unit 14 is configured to generate IGBT open-circuit fault identification results containing the faulty phase.

[0146] The specific execution methods of each unit in the above system embodiments have been described in detail in the embodiments related to the method, and will not be elaborated here.

[0147] In some embodiments, Figure 7 Based on this, the acquisition unit 11 can be implemented through a corresponding sensor, and the first processing unit 12, the second processing unit 13 and the result generation unit 14 can be implemented through a controller or control module with corresponding programs.

[0148] This disclosure also provides a storage medium storing a program or instructions that, when executed by a processor, implement the steps of the method embodiments described above.

[0149] This disclosure also provides a program product, such as... Figure 8 As shown, the program product includes one or more processors 21 and memory 22. Figure 8 Take a processor 21 as an example.

[0150] The controller may also include an input device 23 and an output device 24.

[0151] The processor 21, memory 22, input device 23, and output device 24 can be connected via a bus or other means. Figure 8 Taking the example of a connection between China and Israel via a bus.

[0152] The processor 21 can be a central processing unit (CPU), or it can be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, or combinations of the above types of chips. The general-purpose processor can be a microprocessor or any conventional processor.

[0153] The memory 22, as a non-transitory computer-readable storage medium, can be used to store non-transitory software programs, non-transitory computer-executable programs, and modules, such as the program instructions / modules corresponding to the methods in the embodiments of this disclosure. The processor 21 executes various functional applications and data processing of the server by running the non-transitory software programs, instructions, and modules stored in the memory 22, thereby implementing the steps of the above-described method embodiments.

[0154] The memory 22 may include a program storage area and a data storage area. The program storage area may store the operating system and applications required for at least one function; the data storage area may store data created by the use of the processing device operated by the server. Furthermore, the memory 22 may include high-speed random access memory and may also include non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. In some embodiments, the memory 22 may optionally include memory remotely located relative to the processor 21, and these remote memories may be connected to a network connection device via a network. Examples of such networks include, but are not limited to, the Internet, intranets, local area networks, mobile communication networks, and combinations thereof.

[0155] Input device 23 can receive input digital or character information, and generate key signal inputs related to driver settings and function control of the server's processing unit. Output device 24 may include display devices such as a display screen.

[0156] One or more modules are stored in memory 22, and when executed by one or more processors 21, they perform actions such as... Figure 1 The method shown.

[0157] Those skilled in the art will understand that all or part of the processes in the above method embodiments can be implemented by a computer program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, it can include the processes described in the above method embodiments. The storage medium can be a magnetic disk, optical disk, read-only memory (ROM), random access memory (RAM), flash memory (FM), hard disk drive (HDD), or solid-state drive (SSD), etc.; the storage medium can also include combinations of the above types of memory.

[0158] Although embodiments of the present disclosure have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present disclosure, and such modifications and variations all fall within the scope defined by the appended claims.

[0159] Although embodiments of the present disclosure have been shown and described above, it is to be understood that the above embodiments are exemplary and should not be construed as limiting the present disclosure. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present disclosure.

Claims

1. A method for identifying open-circuit faults in IGBTs of multiphase motors, applied to motor drivers electrically connected to multiphase motors, characterized in that... include: Obtain the actual speed of a multiphase motor; When the actual rotational speed is greater than a set rotational speed threshold, a first diagnostic strategy is initiated, wherein the first diagnostic strategy is used to perform harmonic analysis based on the phase current of each phase of the multiphase motor to locate the faulty phase in which the IGBT open circuit fault occurs. When the actual rotational speed is less than a set speed threshold, a second diagnostic strategy is activated. This second diagnostic strategy is used to locate the faulty phase with an IGBT open-circuit fault based on the duty cycle and current of each phase of the multi-phase motor. Generate IGBT open-circuit fault identification results that include the faulty phase.

2. The method according to claim 1, characterized in that, The first diagnostic strategy is configured as follows: Obtain the current of each phase of the multiphase motor; Determine whether the current of each phase of the multiphase motor meets the preset first constraint condition used to prevent the first diagnostic strategy from mispositioning. When the phase currents of the multiphase motor satisfy the first constraint condition, VSD coordinate transformation is performed on the phase currents of the multiphase motor to obtain the current components of the xy harmonic plane. The total amplitude of the harmonic current is generated based on the current components of the xy harmonic plane; as well as, When the total amplitude of the harmonic current is greater than the preset fault judgment current threshold, the fault phase is located by matching the current components of the xy harmonic plane with the preset correspondence between the fault phase and the harmonic current trajectory.

3. The method according to claim 2, characterized in that, The step of determining whether the phase currents of the multiphase motor meet the preset first constraint condition for preventing mispositioning by the first diagnostic strategy includes: The absolute values ​​of the current in each phase of the multiphase motor are taken and accumulated to generate the accumulated current value for each phase. The accumulated current values ​​of each phase are sorted to obtain the maximum and minimum accumulated current values; To verify the first constraint condition, it is determined whether the maximum accumulated current value is greater than the product of the minimum accumulated current value and the number of motor phases; and, If the maximum accumulated current value is greater than the product of the minimum accumulated current value and the number of phases of the motor, it is determined that the current of each phase of the multiphase motor satisfies the first constraint condition.

4. The method according to any one of claims 1-3, characterized in that, The second diagnostic strategy is configured as follows: Obtain the duty cycle of each phase of the multiphase motor; For each target phase of the multiphase motor, determine whether its duty cycle meets the preset second constraint condition used to prevent the second diagnostic strategy from mispositioning; When the duty cycle satisfies the second constraint condition, the actual current of the target phase is obtained; Based on the actual current, identify whether the target phase has an IGBT open-circuit fault, and generate the IGBT open-circuit fault diagnosis result for the target phase; as well as, Based on the IGBT open-circuit fault diagnosis results for each target phase, the faulty phase is located.

5. The method according to claim 4, characterized in that, The determination of whether its duty cycle meets the preset second constraint condition for preventing the second diagnostic strategy from mislocating includes: Determine whether the duty cycle of the target phase is within a set range and the duration of the duty cycle of the target phase being within the set range exceeds a set time, in order to verify the second constraint condition; If so, determine that the duty cycle satisfies the second constraint condition; and, If not, the duty cycle is determined to not satisfy the second constraint condition.

6. The method according to claim 4, characterized in that, The step of identifying whether an IGBT open-circuit fault has occurred in the target phase based on the actual current includes: In response to the actual current being less than a preset current judgment threshold, it is determined that an IGBT open-circuit fault has occurred in the target phase; and, In response to the actual current being greater than or equal to a preset current judgment threshold, it is determined that the target phase has not experienced an IGBT open-circuit fault.

7. The method according to claim 2 or 3, characterized in that, Also includes: Obtain the voltage of each phase of the multiphase motor; The initial value of the fault judgment current threshold is generated based on the phase voltage of the multiphase motor. Obtain the actual operating parameters of the multiphase motor, wherein the actual operating parameters include actual speed and actual torque; as well as, The initial value of the fault judgment current threshold is adjusted based on the actual operating parameters to generate the final fault judgment current threshold.

8. The method according to any one of claims 1-3, characterized in that, Also includes: After detecting a hardware drive fault signal in the motor driver, a control command is generated to obtain the actual speed of the multiphase motor, thereby initiating IGBT open circuit fault identification. A fault signal is generated based on the fault phase located by the first or second diagnostic strategy. Verify whether the timing stability of the fault signal meets the set criteria; and, When the timing stability of the fault signal meets the set standard, a control command is issued to generate the IGBT open-circuit fault identification result.

9. A multiphase motor IGBT open-circuit fault identification system, applied to a motor driver electrically connected to a multiphase motor, characterized in that, include: The acquisition unit is configured to acquire the actual speed of the multiphase motor; The first processing unit is configured to activate a first diagnostic strategy when the actual rotational speed is greater than a set rotational speed threshold. The first diagnostic strategy is used to perform harmonic analysis based on the phase current of each phase of the multiphase motor to locate the faulty phase in which the IGBT open circuit fault occurs. The second processing unit is configured to activate a second diagnostic strategy when the actual rotational speed is less than a set rotational speed threshold. This second diagnostic strategy is used to locate the faulty phase experiencing an IGBT open-circuit fault based on the duty cycle and current of each phase of the multi-phase motor. The result generation unit is configured to generate IGBT open-circuit fault identification results containing the faulty phase.

10. A storage medium, characterized in that, The storage medium stores a program or instructions, wherein the program or instructions, when executed by a processor, implement the steps of the method as described in any one of claims 1 to 8.

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