Power and dragging loop integrated multi-dimensional monitoring control fault diagnosis method

Abstract

The invention belongs to the technical field of circuit protection, and particularly relates to a power and dragging loop integrated multi-dimensional monitoring control fault diagnosis method and system, and the method comprises the steps: obtaining multi-dimensional physical variables of a power loop and a dragging loop through an intelligent controller and a power distribution monitoring terminal, so as to construct a monitoring data set with a synchronous time sequence; obtaining a dynamic impedance characteristic sequence according to the power side voltage, the dragging side current and the contact temperature; acquiring an impedance response residual sequence according to the dynamic impedance characteristic sequence and a standard impedance model; and obtaining an electrical contact damage index and a mechanical load abnormal index according to the impedance response residual sequence and the contact temperature sequence, and performing fault source diagnosis. According to the method, the dynamic impedance is calculated to offset the voltage fluctuation, the thermal effect is deducted through temperature correction, and the impedance residual error and the temperature data are combined, so that accurate classification and diagnosis of the electrical contact damage and the mechanical load abnormity are realized.

Description

Technical Field

[0001] This invention relates to the field of circuit protection technology. More specifically, this invention relates to a multi-dimensional monitoring and control fault diagnosis method integrating power and drive circuits. Background Technology

[0002] As the core energy transmission and control unit of industrial production equipment, the power and drive circuits directly affect the continuity and safety of the production line. In the petroleum, chemical, coal mining, and various automated manufacturing fields, electric motors and their power distribution systems operate under high loads and continuous conditions for extended periods, making them highly susceptible to faults such as poor contact, insulation aging, or mechanical jamming. Failure to detect and accurately diagnose these faults in a timely manner can lead to equipment downtime and production interruptions, or even electrical fires or severe mechanical damage. Therefore, real-time monitoring and fault diagnosis of power and drive circuits are crucial for safe industrial production.

[0003] In related technologies, a method based on electrical quantity threshold judgment is commonly used to monitor circuits. This method typically acquires the voltage and current signals of the circuit through a data acquisition device installed in a distribution cabinet or control box, and calculates the effective value of the current or the basic impedance value. When the monitored current exceeds a certain multiple of the rated current, or the calculated impedance value deviates from the set range, the system determines that the circuit has an overload, short circuit, or abnormality, and triggers an alarm or trip action, thereby achieving basic protection for the motor and circuit.

[0004] However, current technologies primarily rely on single electrical quantity thresholds for judgment, neglecting the nonlinear interference of complex industrial conditions and environmental factors on monitoring data. Firstly, the power distribution side and drive control side are typically physically separated, and the independently collected data lack a unified time reference, making direct comparison prone to analytical errors. Secondly, traditional methods do not consider grid voltage fluctuations and conductor resistivity drift due to temperature rise, easily misinterpreting normal voltage changes or thermal effects as equipment failures, resulting in a high false alarm rate. Therefore, existing technologies have certain limitations in monitoring and diagnosing power and drive circuits. Summary of the Invention

[0005] To address the technical problems in power and drive circuit monitoring, such as data timing misalignment, susceptibility to voltage fluctuations and temperature rise leading to false alarms, and difficulty in distinguishing between electrical contact faults and mechanical load faults, this invention provides a multi-dimensional monitoring and control fault diagnosis method integrating power and drive circuits. The method includes: acquiring the three-phase voltage magnitude, the three-phase current magnitude, and contact temperature from the power side; obtaining the instantaneous apparent impedance based on the three-phase voltage magnitude and the three-phase current magnitude from the drive side; numerically correcting the instantaneous apparent impedance based on the difference between the contact temperature and the ambient reference temperature and the rated temperature rise limit of the contacts to obtain the instantaneous dynamic equivalent impedance value, thereby constructing a dynamic impedance characteristic sequence; obtaining a standard impedance model sequence and calculating the dynamic impedance. The absolute value of the difference between the values ​​in the impedance characteristic sequence and the corresponding values ​​in the standard impedance model sequence is used to obtain the instantaneous impedance residual value based on the absolute value of the difference and a weighting coefficient that gradually increases over time, thus constructing an impedance response residual sequence. The mean of the impedance response residual sequence is obtained. A temperature rise sequence is constructed based on the difference between each value in the contact temperature sequence and the ambient reference temperature, and the mean of the temperature rise sequence is obtained. The electrical contact damage index is obtained based on the mean of the impedance response residual sequence and the mean of the temperature rise sequence. The mechanical load anomaly index is obtained based on the difference between the mean of the standard impedance model sequence and the mean of the dynamic impedance characteristic sequence, combined with the mean of the temperature rise sequence. Fault source diagnosis is performed based on the electrical contact damage index and the mechanical load anomaly index.

[0006] This invention acquires impedance values ​​by collecting power-side voltage and drive-side current, thus offsetting the impact of grid voltage fluctuations on load current changes and ensuring that the monitoring results only reflect the load's current-carrying capacity. The invention numerically corrects the impedance values ​​based on the difference between contact temperature and ambient reference temperature, eliminating the natural resistivity drift caused by temperature increases in the conductor. This ensures that the acquired impedance characteristics only reflect the health of the equipment's physical structure, avoiding false alarms caused by normal temperature rises. The invention compares the impedance characteristics with a standard model and obtains the residuals. Combined with weighting coefficients that gradually increase over time, it shields the nonlinear fluctuations caused by electromagnetic transients and contact jitter during the initial motor startup, focusing the diagnostic focus on the stable operation phase of the equipment. Furthermore, by combining impedance residuals with temperature rise data, and utilizing the difference between electrical faults accompanied by high heat and the initial mechanical faults accompanied by cold overcurrent, this invention distinguishes between electrical connection faults and mechanical load faults, improving the accuracy of industrial equipment fault diagnosis.

[0007] Preferably, the acquisition of the three-phase voltage magnitude on the power side, the three-phase current magnitude on the drive side, and the contact temperature includes: acquiring the three-phase voltage sequence of the power circuit through a power distribution monitoring terminal, acquiring the three-phase current sequence and contact temperature sequence of the drive circuit through an intelligent controller, and recording the control commands in the control circuit; aligning the three-phase voltage sequence, three-phase current sequence, and contact temperature sequence with timestamps using a network time synchronization protocol, and extracting data within a preset time period before and after the issuance of the control commands to construct a time-synchronized monitoring dataset.

[0008] Preferably, obtaining the instantaneous apparent impedance based on the three-phase voltage magnitude of the power side and the three-phase current magnitude of the drive side includes: for each sampling time, calculating the ratio of the three-phase voltage magnitude of the power side to the three-phase current magnitude of the drive side at that time, and obtaining the instantaneous apparent impedance.

[0009] Preferably, the instantaneous dynamic equivalent impedance value satisfies the following relationship: In the formula, For the first The instantaneous dynamic equivalent impedance value calculated at each sampling time point For the first The three-phase voltage magnitude on the power side at a given moment. For the first The magnitude of the three-phase current on the drag side at each moment. For the first The contact temperature at that moment. The ambient reference temperature This is the rated temperature rise limit of the contact. This is the thermal correction factor.

[0010] This invention corrects the instantaneous apparent impedance downward based on the difference between the contact temperature and the ambient reference temperature. By utilizing the characteristic that the resistivity of a metallic conductor increases with temperature, the portion of the impedance value that naturally increases due to the increase in contact temperature is removed from the calculation results. This ensures that the corrected impedance value reflects the structural integrity and contact tightness of the conductor itself, preventing the temperature rise effect generated during normal high-load operation of the equipment from being misjudged as circuit aging or poor contact, and reducing the false alarm rate of the equipment under high-temperature conditions.

[0011] Preferably, the step of obtaining the standard impedance model sequence includes: identifying the current control command type and load type, retrieving the matching standard impedance model sequence from a preset database, and aligning the dynamic impedance characteristic sequence with the standard impedance model sequence on the time axis.

[0012] Preferably, the instantaneous impedance residual value satisfies the following relationship: In the formula, For the first The instantaneous impedance residual value calculated at each moment For the first The instantaneous dynamic equivalent impedance value calculated at each sampling time point For the standard impedance model sequence in the 1st The preset value at a given time. It is a natural constant. This is a time-weighted factor.

[0013] This invention utilizes a weighting coefficient that increases over time to process the instantaneous impedance residual value. By taking advantage of the characteristic that the weighting coefficient is small at the moment of startup and large after stabilization, the data is dynamically weighted. This suppresses data fluctuations caused by electromagnetic shocks and mechanical vibrations at the initial stage of control command issuance, preventing false alarms triggered by unstable data in the early stage of startup. At the same time, the residual information is retained after the process tends to stabilize, enabling the system to capture impedance anomalies in the later stages of operation and improving the anti-interference capability of monitoring.

[0014] Preferably, the electrical contact damage index satisfies the following relationship: In the formula, The electrical contact damage index, The mean of the impedance response residual sequence is given. The mean of the temperature rise sequence is... It is an exponential function. This is the temperature rise sensitivity coefficient.

[0015] This invention combines the average impedance residual and the average temperature rise to obtain the electrical contact damage index, and amplifies the electrical contact damage index when the impedance is abnormal and accompanied by a significant temperature rise. Based on the phenomenon that poor contact leads to increased resistance and heat generation, this invention enables the index to specifically respond to electrical connection faults such as contact oxidation and terminal loosening, while maintaining a low value under mechanical disturbances without significant temperature rise, thereby achieving targeted identification of electrical faults.

[0016] Preferably, the mechanical load anomaly index satisfies the following relationship: In the formula, This is the mechanical load anomaly index. The mean of the standard impedance model sequence, A function that only takes positive values. The mean of the dynamic impedance characteristic sequence is . This is the mean of the temperature rise sequence.

[0017] This invention obtains the mechanical load anomaly index by using the mean of the standard impedance model and the mean of the dynamic impedance characteristics. It utilizes the characteristic that mechanical overload or jamming will lead to an increase in current and thus a decrease in equivalent impedance, so that the mechanical load anomaly index only responds to overcurrent faults, while filtering out faults such as open circuits or poor contact that cause an increase in impedance. In this way, the characteristics of mechanical load anomalies are separated from complex fault phenomena.

[0018] Preferably, the fault source diagnosis based on the electrical contact damage index and the mechanical load abnormality index includes: in response to the electrical contact damage index being greater than or equal to the electrical alarm threshold, immediately sending a trip command to the intelligent controller to cut off the power supply.

[0019] Secondly, the present invention provides a multi-dimensional monitoring and control fault diagnosis system integrating power and drive circuits, including a processor and a memory. The memory stores computer program instructions, and when the computer program instructions are executed by the processor, the above-mentioned multi-dimensional monitoring and control fault diagnosis method integrating power and drive circuits is implemented.

[0020] The beneficial effects of this invention are as follows: This invention performs spatiotemporal alignment and correlation analysis on the monitoring data of the power distribution circuit and the end-drive circuit, overcoming the problems of data independence and information fragmentation caused by the dispersed physical locations of equipment in traditional monitoring schemes; This invention, through mutual verification and correction of multi-dimensional physical variables, eliminates the interference of external environmental factors and normal physical effects on monitoring results under non-stationary operating conditions such as grid voltage fluctuations, ambient temperature changes, and load start-up impacts, reducing the false alarm rate in industrial sites; This invention utilizes the difference between impedance characteristics and thermal characteristics to specifically decompose general overcurrent or impedance anomalies into electrical connection faults and mechanical load faults, achieving the classification and identification of fault sources and solving the deficiency of single current monitoring in distinguishing between line problems and load problems; This invention, by monitoring the rate of change of characteristic indices, can identify performance degradation states before equipment malfunctions, providing a basis for preventive maintenance and replacement plans, and extending the effective operating time of equipment. Attached Figure Description

[0021] Figure 1 This is a flowchart illustrating a multi-dimensional monitoring and control fault diagnosis method integrating power and drive circuits according to the present invention; Figure 2 This is a schematic diagram illustrating the distribution of electrical contact damage index and mechanical load abnormality index in this invention. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0024] This invention discloses a multi-dimensional monitoring and control fault diagnosis method integrating power and drive circuits, referring to... Figure 1 This includes steps S1 to S4: S1. By using intelligent controllers and power distribution monitoring terminals, multi-dimensional physical variables of power circuits and drive circuits are obtained to construct a time-synchronized monitoring dataset.

[0025] It should be noted that power distribution cabinets and motor control cabinets are typically installed in different physical locations, resulting in a time lag in their data acquisition. Directly comparing the data from both sides can lead to significant distortion of calculation results even with minor timing discrepancies. For accurate correlation analysis, it is essential to unify the time references of both sides. Therefore, this invention acquires multidimensional physical variables of the power circuit and drive circuit to construct a time-synchronized monitoring dataset.

[0026] Specifically, the three-phase voltage magnitude sequence on the power side is collected through the power distribution monitoring terminal; the three-phase current magnitude sequence and contact temperature sequence on the drive side are collected through the intelligent controller on the drive side; simultaneously, the ambient reference temperature and control commands in the control loop are collected. All data sequences are timestamped using a network time synchronization protocol, and all data within a preset time period before and after the issuance of control commands are extracted to construct a time-synchronized monitoring dataset.

[0027] S2. Obtain the dynamic impedance characteristic sequence based on the power side voltage, the drive side current, and the contact temperature.

[0028] It should be noted that the current value of the drive circuit is actually a mixed signal affected by multiple factors. It depends not only on the health of the load but also directly on the voltage level on the power side. When the grid voltage fluctuates, the current changes accordingly, and the impedance of the metallic conductor itself naturally drifts with increasing temperature. These parameter changes caused by external power instability and normal thermal effects can easily mask or confuse the true fault characteristics caused by poor line contact or equipment aging. In order to extract the true state of the equipment itself from these complex interferences, this invention compensates for voltage fluctuations by calculating dynamic impedance and subtracts thermal effects through temperature correction.

[0029] Specifically, the moment when the control command changes is located in the monitoring dataset. A time window is set starting from this moment. For each sampling moment within the time window, the three-phase voltage magnitude on the power side and the three-phase current magnitude on the drive side are extracted. The instantaneous apparent impedance at that moment is obtained based on these values. Simultaneously, the contact temperature at that moment is acquired, and the instantaneous apparent impedance is numerically corrected based on this temperature and the contact's rated temperature rise limit to obtain the instantaneous dynamic equivalent impedance value at that moment. Finally, the instantaneous dynamic equivalent impedance values ​​obtained at all moments are arranged in chronological order to construct a dynamic impedance characteristic sequence.

[0030] For example, the length of the time window is 5 seconds. Implementers can determine the preset time window length according to the actual startup characteristics of the dragged load. For example, for large inertia fans or heavy-load soft-start applications, the window can be appropriately extended to 15 seconds to cover the complete transient process.

[0031] For example, the rated temperature rise limit of the contact is 60K. The implementer can determine the rated temperature rise limit of the contact according to the national standards for low-voltage switchgear and controlgear or the technical specifications of the specific contactor product.

[0032] Specifically, the instantaneous dynamic equivalent impedance value satisfies the following relationship: ; In the formula, For the first The instantaneous dynamic equivalent impedance value calculated at each sampling time point For the first The three-phase voltage magnitude on the power side at a given moment. For the first The magnitude of the three-phase current on the drag side at each moment. For the first The contact temperature at that moment. The ambient reference temperature This is the rated temperature rise limit of the contact. This is a thermal correction factor used to linearly correct the impedance value based on temperature changes; in this embodiment, considering that the busbar and contacts are mainly made of copper, The value is 0.004. In other embodiments, the implementer can set this parameter according to the physical properties of the actual conductor material. For example, when the main conductor of the circuit is aluminum, since the resistivity of aluminum changes slightly more with temperature, it can be appropriately increased. When a special silver plating process is used at the connection point to reduce temperature rise sensitivity, the pressure can be appropriately reduced. This is to ensure that the corrected impedance value truly reflects the physical connection status.

[0033] in, It reflects the current carrying capacity of the circuit; the larger the value, the smaller the current response generated on the drive side when the same voltage is applied on the power side, indicating that there may be high impedance faults such as poor contact or broken wires in the circuit. The smaller the value, the more current is generated for the same voltage, indicating that there may be low impedance faults such as overload, locked rotor, or short circuit in the circuit.

[0034] Since the resistivity of metallic conductors naturally increases with rising temperature, to prevent the increase in impedance caused by normal temperature rise from being mistaken for a circuit fault, [further measures are taken]. The instantaneous apparent impedance value is corrected downwards. This applies when the contact temperature... When it rises, The impedance decreases, thus offsetting the increase in impedance due to thermal effects, resulting in a final instantaneous dynamic equivalent impedance value. It can reflect the structural health of the conductor itself, rather than its state after being affected by temperature.

[0035] S3. Obtain the impedance response residual sequence based on the dynamic impedance characteristic sequence and the standard impedance model.

[0036] It should be noted that different types of loads exhibit different impedance change curves when responding to the same control command. For example, the impedance of a directly started motor will rapidly rise from its minimum value to its steady-state value. If the impedance trajectory during actual operation deviates from this fixed physical change pattern, it means that the physical characteristics of the circuit have changed. Furthermore, at the initial moment of control command issuance, due to the intense electromagnetic transient process accompanied by contact jitter, the data often contains oscillations and noise, resulting in low reliability. To eliminate interference during the initial startup phase and accurately measure the degree of abnormality in the equipment's state, this invention obtains the impedance response residual sequence based on the dynamic impedance characteristic sequence and the standard impedance model.

[0037] Specifically, the current control command type and load type are identified, and a matching standard impedance model sequence is retrieved from a preset database. The dynamic impedance characteristic sequence and the standard impedance model sequence are aligned on the time axis. For each aligned sampling moment, the absolute value of the difference between the instantaneous value in the dynamic impedance characteristic sequence and the corresponding value in the standard impedance model sequence is calculated; simultaneously, a weighting coefficient that gradually increases over time is constructed, and the instantaneous impedance residual value at that moment is obtained based on the absolute value and the weighting coefficient. The instantaneous impedance residual values ​​calculated at all moments are arranged in chronological order to construct the impedance response residual sequence.

[0038] Specifically, the instantaneous impedance residual value satisfies the following relationship: ; In the formula, For the first The instantaneous impedance residual value calculated at each moment For the first The instantaneous dynamic equivalent impedance value calculated at each sampling time point For the standard impedance model sequence in the 1st The preset value at a given time. It is a natural constant. This is a time-weighted factor used to control the duration of masking unstable data during the initial startup phase; its empirical value range is [0.3, 0.8]. In this embodiment, The value is 0.5. In other embodiments, the implementer can adjust it according to the starting characteristics of the driven load. For example, when the monitored object is a large inertia fan starting under heavy load, its starting current oscillation time is relatively long. To avoid false alarms, the shielding time needs to be extended. In this case, the value should be appropriately reduced. When the monitored object is a soft-start device controlled by a frequency converter, the current stabilizes relatively quickly. In order to intervene in monitoring as early as possible, the current can be appropriately increased. .

[0039] in, It reflects the degree to which the actual operating conditions deviate from the ideal physical state; the larger the value, the more likely the electrical characteristics of the circuit are to be severely distorted, which means that the faults such as excessive contact resistance, short circuit between coil turns or mechanical jamming are more severe; the smaller the value, the more consistent the system's operating state is with the design expectation, and the healthier the system is. This represents the time masking weight for transient processes, due to the initial instant of the control command being issued ( When the voltage and current values ​​are 0, the transient fluctuations in the voltage and current data are extremely large and the measurements are inaccurate. Approaching 0, for It performs strong attenuation, which helps to suppress initial noise and avoid false alarms; as the process stabilizes, The value quickly approaches 1, enabling the residual calculation to take full effect, thereby ensuring that the diagnostic focus is on the stability of the mid-to-late stages of the response process.

[0040] S4. Obtain the electrical contact damage index and mechanical load anomaly index based on the impedance response residual sequence and contact temperature sequence, and perform fault source diagnosis.

[0041] It should be noted that a single impedance anomaly may correspond to multiple fault modes, and the specific cause of the fault cannot be determined solely by impedance deviation. For example, excessive circuit impedance may be caused by electrical connection faults such as contactor contact oxidation, or by internal equipment faults such as broken motor rotor bars; while insufficient impedance usually indicates excessive current, which may be caused by mechanical load jamming or may be a precursor to a short circuit. Poor contact at connection points is inevitably accompanied by abnormal temperature rise, and simple mechanical overload usually only manifests as increased current and decreased impedance in the initial stage, without a sudden change in contact temperature. Therefore, this invention combines impedance residuals with temperature data, utilizing the combined characteristics of the two under different fault conditions to classify the nature of the fault.

[0042] Specifically, the mean of the impedance response residual sequence is obtained, and the temperature rise sequence is obtained by extracting the temperature increase value of the contact temperature sequence relative to the ambient temperature. Simultaneously, the mean of the dynamic impedance characteristic sequence and the mean of the standard impedance model sequence are statistically analyzed. The electrical contact damage index is obtained based on the arithmetic mean of the impedance response residual sequence and the temperature rise value.

[0043] Specifically, the electrical contact damage index satisfies the following relationship: ; In the formula, The electrical contact damage index, The mean of the impedance response residual sequence is given. The mean of the temperature rise sequence is... It is an exponential function. The temperature rise sensitivity coefficient is used to adjust the amplification of the temperature rise weight in fault determination. Its empirical value range is [0.5, 1.2]. In this embodiment, The value is 0.8. In other embodiments, implementers can set the value according to the security level of the application scenario. For example, in high-risk environments with zero tolerance for electrical fires, such as underground coal mines, the value can be appropriately increased to trigger a high-index alarm in the initial, weak stage of temperature rise. In well-ventilated, typical industrial environments where a certain temperature rise is permissible, the alarm frequency can be appropriately reduced to minimize false alarms caused by ambient temperature fluctuations. .

[0044] in, This reflects the overall degree to which the circuit's electrical characteristics deviate from a preset reference throughout the entire dynamic response process. When the circuit is in a healthy state, its transient impedance trajectory should closely fit the standard model. Approaching zero; when The larger the value, the more significant the nonlinear fluctuation or continuous deviation of the equivalent impedance of the circuit during startup or operation. This deviation is usually caused by unstable contact resistance due to oxidation of the contact surface, arc disturbance caused by loose terminals, or sudden leakage current caused by aging of internal insulation of the equipment. Therefore, the larger the electrical contact damage index, the greater the value.

[0045] Poor contact can lead to both impedance instability and heat generation. Therefore, when the impedance is abnormal and the temperature rises... At higher levels, The larger the value, the greater the electrical contact damage index, thus accurately pointing to electrical connection faults; The lower the value, the more likely the contact is to be in a normal thermal equilibrium state, and no abnormal Joule heating effect has occurred. The closer it is to 1, the worse it is. It amplifies the effect, preventing simple mechanical disturbances from being misjudged as serious contact failures.

[0046] Furthermore, the mechanical load anomaly index is obtained by combining the mean of the standard impedance model sequence and the mean of the dynamic impedance characteristic sequence with the mean of the temperature rise sequence.

[0047] Specifically, the mechanical load anomaly index satisfies the following relationship: ; In the formula, This is the mechanical load anomaly index. The mean of the standard impedance model sequence, A function that only takes positive values. The mean of the dynamic impedance characteristic sequence is . This is the mean of the temperature rise sequence.

[0048] in, This reflects the degree to which the actual impedance is less than the standard impedance; when Less than hour, A positive value indicates that the circuit generated a much higher-than-expected current under the same voltage. This typically corresponds to jamming on the mechanical load side or a torque surge caused by bearing failure. Therefore, The larger the value, the more likely overcurrent faults are to occur, and the greater the mechanical load anomaly index; when and Approaching or Greater than hour, A value of 0 indicates that the circuit impedance is normal or too high (e.g., an open circuit), ruling out the possibility of overload or short circuit. The value is set to 0, so that the mechanical load anomaly index only responds to the condition of increased current, thus avoiding false alarms for non-overcurrent faults.

[0049] when A higher Joule temperature indicates that significant Joule heat has likely accumulated at the contacts, usually due to excessive contact resistance caused by oxidation of the contact surface or prolonged overload operation. This high-current phenomenon accompanied by high temperature... Approaching 0, it strongly suppresses the abnormal mechanical load index, preventing electrical faults with obvious thermal characteristics from being misjudged as pure mechanical jamming. Conversely, when... The smaller the value, the colder the system is, indicating that the fault occurred very quickly, corresponding to a sudden mechanical stall or a momentary impact load. In this case, although the motor current increases sharply, the contact temperature does not rise in time due to thermal inertia. The larger, the better It amplifies the mechanical load abnormality index, enabling the detection of sudden current changes in the early stages of a fault without thermal signs.

[0050] Furthermore, fault diagnosis is performed based on the electrical contact damage index and the mechanical load anomaly index.

[0051] In one embodiment, electrical alarm thresholds and mechanical alarm thresholds are set. The electrical contact damage index and mechanical load anomaly index are compared with their corresponding thresholds, and a diagnosis is made based on the comparison results. This includes: in response to an electrical contact damage index greater than or equal to the electrical alarm threshold, indicating severe poor contact or insulation failure in the power circuit, an immediate trip command is sent to the intelligent controller to cut off the power supply; in response to a mechanical load anomaly index greater than or equal to the mechanical alarm threshold, indicating severe mechanical jamming or stall in the drive circuit, an immediate stop command is sent to the controller to prevent motor winding burnout. For example, the electrical alarm threshold is 0.8, and the mechanical alarm threshold is 1.2. Implementers can determine the electrical and mechanical alarm thresholds according to the actual situation.

[0052] For example, Figure 2 This is a distribution diagram of the electrical contact damage index and the mechanical load anomaly index in this invention. As can be seen from the diagram, the electrical contact damage index and the mechanical load anomaly index can be used to distinguish between normal operating conditions, electrical contact faults and mechanical load faults. While realizing the fault type determination, it reduces the false alarm rate of fault diagnosis of power and drive circuits under complex working conditions.

[0053] This invention also discloses a multi-dimensional monitoring and control fault diagnosis system integrating power and drive circuits, including a processor and a memory. The memory stores computer program instructions, and when the computer program instructions are executed by the processor, a multi-dimensional monitoring and control fault diagnosis method integrating power and drive circuits according to the present invention is implemented.

[0054] The system also includes other components well known to those skilled in the art, such as communication buses and communication interfaces, the settings and functions of which are known in the art and will not be described in detail here.

Claims

1. A multi-dimensional monitoring and control fault diagnosis method integrating power and drive circuits, characterized in that, include: The three-phase voltage magnitude on the power side, the three-phase current magnitude on the drive side, and the contact temperature are collected. The instantaneous apparent impedance is obtained based on the three-phase voltage magnitude on the power side and the three-phase current magnitude on the drive side. The instantaneous apparent impedance is numerically corrected based on the difference between the contact temperature and the ambient reference temperature and the rated temperature rise limit of the contact to obtain the instantaneous dynamic equivalent impedance value, so as to construct a dynamic impedance characteristic sequence. Obtain a standard impedance model sequence, calculate the absolute value of the difference between the values ​​in the dynamic impedance characteristic sequence and the corresponding values ​​in the standard impedance model sequence, obtain the instantaneous impedance residual value based on the absolute value of the difference and a weighting coefficient that gradually increases over time, and construct an impedance response residual sequence; obtain the mean of the impedance response residual sequence, construct a temperature rise sequence based on the difference between each value in the contact temperature sequence and the ambient reference temperature, and obtain the mean of the temperature rise sequence; obtain the electrical contact damage index based on the mean of the impedance response residual sequence and the mean of the temperature rise sequence; obtain the mechanical load anomaly index based on the difference between the mean of the standard impedance model sequence and the mean of the dynamic impedance characteristic sequence, combined with the mean of the temperature rise sequence. Fault source diagnosis is performed based on the electrical contact damage index and the mechanical load anomaly index.

2. The multi-dimensional monitoring and control fault diagnosis method for integrated power and drive circuits according to claim 1, characterized in that, The acquisition of the three-phase voltage magnitude on the power side, the three-phase current magnitude on the drive side, and the contact temperature includes: acquiring the three-phase voltage sequence of the power circuit through a power distribution monitoring terminal, acquiring the three-phase current sequence and contact temperature sequence of the drive circuit through an intelligent controller, and recording the control commands in the control circuit; aligning the three-phase voltage sequence, three-phase current sequence, and contact temperature sequence with timestamps using a network time synchronization protocol, and extracting data within a preset time period before and after the issuance of the control commands to construct a time-synchronized monitoring dataset.

3. The multi-dimensional monitoring and control fault diagnosis method integrating power and drive circuits according to claim 1, characterized in that, The step of obtaining the instantaneous apparent impedance based on the three-phase voltage magnitude of the power side and the three-phase current magnitude of the drive side includes: for each sampling time, calculating the ratio of the three-phase voltage magnitude of the power side to the three-phase current magnitude of the drive side at that time, and obtaining the instantaneous apparent impedance.

4. The multi-dimensional monitoring and control fault diagnosis method for integrated power and drive circuits according to claim 1, characterized in that, The instantaneous dynamic equivalent impedance value satisfies the following relationship: ； In the formula, For the first The instantaneous dynamic equivalent impedance value calculated at each sampling time point For the first The three-phase voltage magnitude on the power side at a given moment. For the first The magnitude of the three-phase current on the drag side at each moment. For the first The contact temperature at that moment. The ambient reference temperature This is the rated temperature rise limit of the contact. This is the thermal correction factor.

5. The multi-dimensional monitoring and control fault diagnosis method for integrated power and drive circuits according to claim 1, characterized in that, The process of obtaining the standard impedance model sequence includes: identifying the current control command type and load type, retrieving the matching standard impedance model sequence from a preset database, and aligning the dynamic impedance characteristic sequence with the standard impedance model sequence on the time axis.

6. The multi-dimensional monitoring and control fault diagnosis method for integrated power and drive circuits according to claim 1, characterized in that, The instantaneous impedance residual value satisfies the following relationship: ； In the formula, For the first The instantaneous impedance residual value calculated at each moment For the first The instantaneous dynamic equivalent impedance value calculated at each sampling time point For the standard impedance model sequence in the 1st The preset value at a given time. It is a natural constant. This is a time-weighted factor.

7. The multi-dimensional monitoring and control fault diagnosis method for integrated power and drive circuits according to claim 1, characterized in that, The electrical contact damage index satisfies the following relationship: ； In the formula, The electrical contact damage index, The mean of the impedance response residual sequence is given. The mean of the temperature rise sequence is... It is an exponential function. This is the temperature rise sensitivity coefficient.

8. The multi-dimensional monitoring and control fault diagnosis method for integrated power and drive circuits according to claim 1, characterized in that, The mechanical load anomaly index satisfies the following relationship: ； In the formula, This is the mechanical load anomaly index. The mean of the standard impedance model sequence, A function that only takes positive values. The mean of the dynamic impedance characteristic sequence is . This is the mean of the temperature rise sequence.

9. The multi-dimensional monitoring and control fault diagnosis method for integrated power and drive circuits according to claim 1, characterized in that, The fault source diagnosis based on the electrical contact damage index and the mechanical load abnormality index includes: in response to the electrical contact damage index being greater than or equal to the electrical alarm threshold, immediately sending a trip command to the intelligent controller to cut off the power supply.

10. A multi-dimensional monitoring and control fault diagnosis system integrating power and drive circuits, characterized in that, include: A processor and a memory, wherein the memory stores computer program instructions that, when executed by the processor, implement a multi-dimensional monitoring and control fault diagnosis method for power and drive circuit integration according to any one of claims 1-9.

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