Metal part eddy current loss detection method
By parsing instructions and filtering voltage and current data through the DSP control unit, and combining the moving average filtering algorithm and fault classification strategy, the timeliness and accuracy of eddy current loss detection in metal connectors of power grid equipment are solved, thereby improving the safety and stability of the power grid.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-19
- Publication Date
- 2026-04-03
AI Technical Summary
Metal connectors in power grid equipment are prone to eddy current losses under high-frequency electromagnetic excitation, leading to equipment overheating, insulation aging, and reduced operating efficiency, which affects the safe and stable operation of the power grid. Existing detection methods are not timely or accurate enough.
By employing the eddy current loss detection method, the DSP control unit parses instructions, acquires and filters voltage and current data, and combines a moving average filtering algorithm and a fault classification processing strategy to achieve accurate monitoring and early warning of anomalies in metal connectors.
It improves the accuracy and safety of testing metal connectors in power grid equipment, reduces fault diagnosis time, and ensures the stable operation of the power grid.
Smart Images
Figure CN121784400A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of power equipment testing, and specifically to a method for detecting eddy current losses in metal parts. Background Technology
[0002] Metal connectors in power grid equipment (such as GIS equipment connectors and conductor joints) are prone to eddy current losses under high-frequency electromagnetic excitation. Long-term accumulation can lead to equipment overheating, insulation aging, decreased operating efficiency, and even safety accidents, directly affecting the safe and stable operation of the power grid. With the increasing prevalence of high-voltage and ultra-high-voltage substations, the requirements for the timeliness and accuracy of metal connector loss detection are becoming increasingly stringent. Summary of the Invention
[0003] This invention provides the following technical solution: A method for detecting eddy current loss in metal parts includes the following steps: Connect the test piece to the device under test, initialize the device configuration, and select either eddy current loss detection mode or wireless power supply mode. Configure the scanning frequency band parameters or power output reference parameters according to the currently selected mode. Command transmission and parsing: The configuration parameters are converted into RS-485 protocol commands, which are then transmitted to the DSP control unit via the RS-485 communication module. After receiving the commands, the DSP control unit parses them to identify the working mode and the corresponding parameters to be acquired. The parameters of the device under test are acquired, and the collected analog signals are converted into digital signals and fed back to the DSP control unit. The collected data is filtered, and the voltage and current data are smoothed using a moving average filtering algorithm, and the parameters are output. The status of the device under test is determined by comparing the output parameters with the preset parameters. If the parameter is greater than the preset value, the device under test is judged to be abnormal, and an alarm is issued or the detection device is shut down.
[0004] Furthermore, when the eddy current loss detection mode is selected, the starting scan frequency band, step scan frequency band, and ending scan frequency band are configured according to the PRD table, and the number of data points is 10 points / time; If wireless power supply mode is selected, set the power output reference parameters, set the serial port baud rate to 115200, start the timer and put it into data refresh and status polling state.
[0005] Furthermore, the parameters of the device under test include: the voltage, current, and impedance of the device under test; after acquiring the voltage, current, and impedance data, the device under test converts the analog signals into digital signals and feeds them back to the DSP control unit.
[0006] Furthermore, in the eddy current loss detection mode, two time windows, ON and OFF, are constructed within the ePWM2 interrupt. During the ON window, the product of Buck output voltage and current is accumulated, and when the OFF window ends, the average power is calculated to obtain the eddy current loss value at each frequency point.
[0007] Furthermore, the filtering process for the collected data includes: creating graphs and data tables after receiving the data, comparing the graphs and data tables with preset data, and marking anomalies in the graphs and data tables.
[0008] Furthermore, the filtering process for the collected data includes: a data calibration step, which involves calibrating the data using a preset standard resistance load, obtaining calibration coefficients at different frequency points, multiplying the calculated average power by the calibration coefficients at the corresponding frequency points, and obtaining the calibrated eddy current loss value.
[0009] Furthermore, obtaining the parameters of the device under test also includes: In wireless power supply mode, a phase-shifting soft-start strategy is adopted to gradually adjust the phase shift angle of the PWM signal from 0° to the target phase shift angle, with an adjustment step size of 5° / 20ms. Furthermore, the parameters of the device under test are obtained as follows: if it is an eddy current loss detection mode, a duty cycle ramp-up soft-start strategy is adopted, and the duty cycle of the Buck converter is gradually increased from 10% to the target duty cycle at an increase rate of 5% / 10ms.
[0010] Furthermore, it also includes fault classification and handling strategies; Faults are classified into Level 1 and Level 2 faults. When a Level 1 fault is detected, the DSP immediately shuts off the inverter drive signal and marks the fault type. When a Level 2 fault is detected, the DSP reduces the power output to 50% of the rated power, issues a fault warning, and displays a yellow warning message. If the fault persists for a preset time without being eliminated, it is escalated to Level 1 fault handling.
[0011] Furthermore, the detection element can be a Hall sensor or a Rogowski coil. When a Hall sensor is used, the sensor's measurement range is 0-50V for voltage and 0-20A for current, with an accuracy class of 0.5 and an output signal of 4-20mA current signal.
[0012] The selection of either eddy current loss detection mode or wireless power supply mode is determined based on the requirements of the testing task. Specifically, this can be done manually by the operator, for example, using a physical switch on the control panel or an option menu in the software interface. Converting configuration parameters into RS-485 protocol commands means encoding parameter data into an instruction format conforming to the RS-485 communication standard. This can be implemented using hardware conversion circuits, such as a communication module integrating a MAX485 transceiver, or by directly generating protocol frames through the microcontroller's built-in serial interface. The DSP control unit then receives and parses the commands, identifying the operating mode and the corresponding parameters to be acquired. For example, acquiring electrical characteristic data of the device under test during operation can be achieved by directly measuring the device and converting the analog signal into a digital signal, which is then fed back to the DSP control unit. After acquiring the digital signal, the DSP control unit uses a moving average filtering algorithm to smooth the voltage and current data to suppress noise interference. This can be implemented using digital signal processing technology, such as setting a sliding window in the DSP to store data points, assigning higher weights to historical data during calculation to maintain trend continuity, and lower weights to new data to adapt to real-time changes. Finally, judging the current status of the device under test by comparing the output parameters with the preset parameters refers to identifying abnormal situations by comparing real-time data with the threshold range. This can be achieved by using a comparator circuit or a software threshold judgment algorithm. For example, when the parameter exceeds the preset upper limit, an alarm mechanism is triggered or the power supply of the detection device is cut off, so as to achieve accurate monitoring and abnormal early warning of eddy current loss of metal connectors in power grid equipment under high-frequency electromagnetic excitation. Attached Figure Description
[0013] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.
[0014] Figure 1 A flowchart of a method for detecting eddy current loss in metal parts provided in an embodiment of the present invention. Detailed Implementation
[0015] 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 embodiments of the present invention, and not all embodiments. 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.
[0016] The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this invention are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or apparatuses.
[0017] In this document, references to "embodiment" or "implementation" mean that a particular feature, structure, or characteristic described in connection with an embodiment or implementation may be included in at least one embodiment of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.
[0018] Please see Figure 1 A method for detecting eddy current loss in metal parts, comprising the following steps: Connect the test piece to the device under test, initialize the device configuration, and select either eddy current loss detection mode or wireless power supply mode. Configure the scanning frequency band parameters or power output reference parameters according to the currently selected mode. Command transmission and parsing: The configuration parameters are converted into RS-485 protocol commands, which are then transmitted to the DSP control unit via the RS-485 communication module. After receiving the commands, the DSP control unit parses them to identify the working mode and the corresponding parameters to be acquired. The parameters of the device under test are acquired, and the collected analog signals are converted into digital signals and fed back to the DSP control unit. The collected data is filtered, and the voltage and current data are smoothed using a moving average filtering algorithm, and the parameters are output. The status of the device under test is determined by comparing the output parameters with the preset parameters. If the parameter is greater than the preset value, the device under test is judged to be abnormal, and an alarm is issued or the detection device is shut down.
[0019] The selection of either eddy current loss detection mode or wireless power supply mode is determined based on the requirements of the testing task. Specifically, this can be done manually by the operator, for example, using a physical switch on the control panel or an option menu in the software interface. Converting configuration parameters into RS-485 protocol commands means encoding parameter data into an instruction format conforming to the RS-485 communication standard. This can be implemented using hardware conversion circuits, such as a communication module integrating a MAX485 transceiver, or by directly generating protocol frames through the microcontroller's built-in serial interface. The DSP control unit then receives and parses the commands, identifying the operating mode and the corresponding parameters to be acquired. For example, acquiring electrical characteristic data of the device under test during operation can be achieved by directly measuring the device and converting the analog signal into a digital signal, which is then fed back to the DSP control unit. After acquiring the digital signal, the DSP control unit uses a moving average filtering algorithm to smooth the voltage and current data to suppress noise interference. This can be implemented using digital signal processing technology, such as setting a sliding window in the DSP to store data points, assigning higher weights to historical data during calculation to maintain trend continuity, and lower weights to new data to adapt to real-time changes. Finally, judging the current status of the device under test by comparing the output parameters with the preset parameters refers to identifying abnormal situations by comparing real-time data with the threshold range. This can be achieved by using a comparator circuit or a software threshold judgment algorithm. For example, when the parameter exceeds the preset upper limit, an alarm mechanism is triggered or the power supply of the detection device is cut off, so as to achieve accurate monitoring and abnormal early warning of eddy current loss of metal connectors in power grid equipment under high-frequency electromagnetic excitation.
[0020] In some implementations, when the eddy current loss detection mode is selected, the start scan frequency band, step scan frequency band, and end scan frequency band are configured according to the PRD table, and the number of data points is 10 points / time. If wireless power supply mode is selected, set the power output reference parameters, set the serial port baud rate to 115200, start the timer and put it into data refresh and status polling state.
[0021] Understandably, the PRD table is a parameter configuration reference table, which can be stored in a predefined data table in the DSP control unit or in external memory. It can be used directly by calling the table to improve detection efficiency. The start scan band, step scan band, and end scan band, as well as the number of data points, are used to ensure that the scanning process covers the critical frequency range and sampling density where the device is prone to eddy current losses, enabling the measurement data to accurately reflect the continuity of loss changes within the frequency band. In practical applications, the power output reference parameter refers to the target power value in wireless power supply mode, which can be achieved using a preset value or a dynamically adjusted reference, aiming to ensure the stability and controllability of the output power. The serial port baud rate of 115200 refers to the transmission rate of the RS-485 communication module, aiming to optimize the real-time performance and anti-interference capability of command transmission. Specifically, starting the timer and putting it in data refresh and status polling state means configuring the timer to periodically execute monitoring tasks, which can be achieved using an interrupt-driven polling mechanism or an event-triggered mechanism, aiming to achieve continuous monitoring of the system's operating status. Specifically, when the user selects the eddy current loss detection mode, the system automatically configures the starting scan frequency band, step scan frequency band, and ending scan frequency band according to the PRD table. This ensures that the scanning process strictly covers the key frequency band range that is prone to eddy current loss under high-frequency electromagnetic excitation. Simultaneously, the system sets the number of data points to 10 per scan, providing sufficient sampling points to capture the continuity of loss changes within the frequency band. If the wireless power supply mode is selected, the system sets the power output reference parameters to maintain the stability of the output power, sets the serial port baud rate to 115200 to ensure efficient and reliable command transmission, and starts a timer to refresh data and poll the status, thereby continuously monitoring the system's operating status. This avoids the problems of insufficient detection accuracy and system instability caused by ambiguous parameter settings in the detection of eddy current losses in metal parts, ensuring the accuracy of the scanning frequency band coverage and the reliability of command transmission, thus improving the safety detection capability of metal connectors in power grid equipment under complex operating conditions.
[0022] In some implementations, the parameters of the device under test include: voltage, current, and impedance of the device under test; after acquiring the voltage, current, and impedance data, the device under test converts the analog signals into digital signals and feeds them back to the DSP control unit.
[0023] Understandably, the instantaneous product of voltage and current directly represents instantaneous power, thus supporting the accurate calculation of eddy current loss, while impedance reveals the dynamic characteristics of eddy current distribution inside the metal part through its amplitude and phase changes. After acquiring these parameters, the detection device converts the analog signal into a digital signal through an analog-to-digital converter to ensure data fidelity. Finally, the digital signal is stably transmitted to the DSP control unit, forming a standardized path from physical quantity acquisition to digital processing, thereby providing a consistent and complete data source for subsequent steps such as filtering and state judgment, avoiding detection blind spots caused by missing parameters or signal distortion.
[0024] In some implementations, the detection device uses an electromagnetic induction current sensor to collect current signals and a high-impedance voltage divider network to obtain voltage signals. The impedance is calculated based on the phase difference of the synchronous sampling data of voltage and current. The analog signal is converted into a digital signal by a 12-bit precision analog-to-digital converter. The conversion process includes pre-filtering to suppress high-frequency noise. The converted digital signal is transmitted to the DSP control unit in real time through a parallel data bus, where it performs data buffering and preliminary verification to ensure the reliability of the signal link, thereby supporting the accurate assessment of the safe operation of power grid equipment.
[0025] Specifically, in some of the embodiments of the present invention described above, it is proposed to obtain voltage and current parameters and perform filtering. However, in the process of implementation, for the eddy current loss detection mode, there is a lack of a method to accurately capture the instantaneous power change under high frequency scanning. This makes it easy to be affected by signal fluctuations when directly using the filtered data to calculate the eddy current loss, and it cannot accurately reflect the actual loss value at each frequency point.
[0026] In some implementations, if it is an eddy current loss detection mode, two time windows, ON and OFF, are constructed within the ePWM2 interrupt. During the ON window, the product of Buck output voltage and current is accumulated. When the OFF window ends, the average power is calculated to obtain the eddy current loss value at each frequency point.
[0027] Understandably, the ePWM2 interrupt refers to the interrupt mechanism in a digital signal processor used for precise synchronization of timing events, aiming to ensure that the measurement process is strictly aligned with the switching cycle of the Buck converter. The ON / OFF time windows can be understood as the conduction and turn-off time periods divided within the switching cycle, which can be implemented using timing logic circuits triggered by the PWM signal edge, with the aim of isolating the power measurement process at different stages. The accumulation of the product of the Buck output voltage and current within the ON window refers to the integration calculation of the instantaneous power during the conduction phase, which can be implemented using a hardware accumulator or a software cyclic accumulation algorithm. The calculation of the average power at the end of the OFF window can be understood as deriving a stable value based on the integral data of the entire switching cycle, which can be implemented through a division unit or a lookup table mapping method, with the aim of suppressing the influence of high-frequency signal fluctuations on the results. Specifically, the ePWM2 interrupt mechanism is used to precisely trigger the construction of the time window, ensuring that the ON / OFF time window is strictly synchronized with the switching cycle of the Buck converter. Within the ON time window, the system continuously accumulates the product of the Buck output voltage and current to form the power integral value during the conduction phase. When the OFF time window ends, the average power of the entire switching cycle is calculated based on this integral value. By repeating this process at different frequencies, the eddy current loss values at each frequency are obtained, thereby eliminating the influence of timing deviations and signal fluctuations and improving the reliability of power calculation.
[0028] Optionally, the DSP control unit uses a TMS320F28377S microcontroller, whose ePWM2 module is configured to generate an interrupt signal at the start of the Buck converter switching cycle.
[0029] In some implementations, filtering the collected data includes: generating graphs and data tables after receiving the data, comparing the graphs and data tables with preset data, and marking anomalies in the graphs and data tables.
[0030] Understandably, creating graphs and data tables involves transforming filtered voltage and current data into graphical and structured representations. This can be achieved using real-time updated line graphs to display data trends and presenting specific values in spreadsheet format. The aim is to eliminate transient noise interference in the original signal, making data trends clearer and facilitating operators' rapid detection of potential anomalies. Comparison with preset data can be understood as automatically matching visualized data with preset thresholds. Threshold comparison algorithms can identify deviations between actual data and preset standards, combining graphical observation and numerical analysis to avoid the limitations of single-value judgments and effectively reduce subjective errors from manual comparison. Furthermore, identified anomalies can be marked in the visualization interface using highlighting or special symbols for intuitive operator observation, reducing reliance on manual analysis, shortening fault diagnosis time, and improving the timeliness and accuracy of equipment status assessment. In some implementations, filtering the acquired data includes: data calibration, which involves calibrating the data using a preset standard resistance load, obtaining calibration coefficients at different frequency points, and multiplying the calculated average power by the calibration coefficients at the corresponding frequency points to obtain the calibrated eddy current loss value.
[0031] Understandably, the preset standard resistance load is a precision resistor or adjustable resistance box with a fixed resistance value. Its purpose is to eliminate inherent biases in the sensor and signal link. The calibration coefficient refers to a correction factor calculated for different frequency points, used to dynamically adapt to system response differences at various frequency points. Specifically, the preset standard resistance load provides a stable reference, eliminating inherent biases in the sensor and signal link and ensuring the reliability of basic data acquisition. Subsequently, considering the frequency scanning characteristics in eddy current loss detection, calibration coefficients at different frequency points are obtained to compensate for system response differences caused by frequency changes. Finally, the calculated average power is multiplied by the calibration coefficient at the corresponding frequency point to achieve real-time correction of the power value. This tightly couples the calibration process with frequency parameters, ensuring consistency between eddy current loss calculation and actual physical phenomena, thereby outputting the calibrated eddy current loss value. This avoids measurement drift caused by frequency changes and improves the accuracy and reliability of eddy current loss detection.
[0032] In some implementations, obtaining the parameters of the device under test further includes: In wireless power supply mode, a phase-shifting soft-start strategy is adopted to gradually adjust the phase shift angle of the PWM signal from 0° to the target phase shift angle, with an adjustment step size of 5° / 20ms. Understandably, the phase-shift soft-start strategy achieves smooth power output startup by gradually adjusting the phase difference of the PWM signal. This can be implemented using a digital signal processor to dynamically configure the phase offset register of the PWM generation module, aiming to avoid sudden current surges during startup. The phase shift angle of the PWM signal can be understood as the phase offset between the inverter bridge arm control signals, which can be calculated and updated in real-time using software algorithms. Specifically, during the wireless power supply mode startup phase, the DSP control unit first initializes the phase shift angle of the PWM signal to 0°, and then gradually adjusts it to the target angle at a rate of 5° every 20 milliseconds, based on a preset step size. This process triggers the phase update operation through a timer interrupt, allowing the power output to rise linearly from its minimum value, avoiding the generation of instantaneous large currents. Since the gradual adjustment of the phase shift angle is directly related to the power output level, the system can maintain a stable power growth curve, preventing system oscillations or measurement errors caused by excessively rapid adjustment rates, thereby ensuring signal accuracy and equipment safety during parameter acquisition. This achieves the goal of improving the accuracy of parameter acquisition and the reliability of equipment operation, avoiding the risk of measurement distortion or hardware damage caused by sudden current changes, thereby ensuring the safe and stable execution of the testing process.
[0033] In some implementations, obtaining the parameters of the device under test also includes: if it is an eddy current loss detection mode, a duty cycle ramp-up soft-start strategy is adopted, in which the duty cycle of the Buck converter is gradually increased from 10% to the target duty cycle at an increase rate of 5% / 10ms.
[0034] Understandably, the duty cycle ramp-up soft-start strategy is a progressive control method for the Buck converter startup process. It can be implemented by linearly increasing or segmented step-by-step increasing the duty cycle. The Buck converter's duty cycle starts at 10% to avoid initial voltage surges caused by zero duty cycle startup. The initial duty cycle can be determined based on a system-preset safety threshold or by dynamically detecting the bus voltage status. The ramp-up rate of 5% / 10ms refers to the precise rate control of the duty cycle change. It can be achieved by using timed interrupt triggering or digital PID adjustment algorithms to ensure that the rate of change matches the system's dynamic response. Its purpose is to suppress transient current surges and ensure the stability of parameter acquisition. Specifically, by gradually increasing the duty cycle of the Buck converter from 10% in the eddy current loss detection mode, the voltage and current build-up process is adapted to the system inertia, avoiding instantaneous energy release caused by sudden changes in duty cycle. Combined with a 5% / 10ms increase rate control, the duty cycle change rate satisfies the suppression requirements of eddy current effects under high-frequency electromagnetic excitation while preventing excessively slow adjustments from affecting detection efficiency. This ensures the accuracy of key parameter acquisition such as voltage and current under the unique high-frequency operating conditions of the eddy current loss detection mode. For example, when the eddy current loss detection mode is started, the DSP control unit initializes the PWM signal duty cycle of the Buck converter to 10%, and then uses ePWM... The module's timer interrupt increments the duty cycle by 5% every 10ms. This incrementing process is performed by TI's TMS320F28335 microcontroller, which calculates and updates the duty cycle. The drive circuit uses an IR2110 half-bridge driver chip to control the conduction time of the power MOSFET. Simultaneously, a Hall sensor monitors the output current changes in real time. When a current fluctuation is detected to exceed the preset safety range, the DSP control unit automatically pauses the duty cycle increment and maintains the current state. After the system stabilizes, it continues to execute the soft-start process. This ensures the stability of parameter acquisition and system safety, improves the accuracy of eddy current loss detection and equipment reliability, and avoids measurement signal distortion or hardware damage caused by transient current surges.
[0035] In some implementations, a fault classification and handling strategy is also included; Faults are classified into Level 1 and Level 2 faults. When a Level 1 fault is detected, the DSP immediately shuts off the inverter drive signal and marks the fault type. When a Level 2 fault is detected, the DSP reduces the power output to 50% of the rated power, issues a fault warning, and displays a yellow warning message. If the fault persists for a preset time without being eliminated, it is escalated to Level 1 fault handling.
[0036] Understandably, fault classification and handling strategies can implement differentiated responses based on the immediate impact of faults on equipment safety. Level 1 faults refer to emergency situations that may cause immediate equipment damage, triggered by parameters such as current overload, abnormal voltage, or excessive temperature. Level 2 faults refer to monitorable potential anomalies, specifically identified based on parameter fluctuations that do not reach dangerous thresholds. The DSP immediately shuts down the inverter and marks the fault type for subsequent diagnosis. Reducing the DSP's power output to 50% of its rated power means adjusting the output power level, which can be achieved by adjusting the PWM duty cycle or changing the reference voltage. Specifically, when the system identifies anomalies based on parameter comparison, it first determines the level based on the immediate impact of the fault on equipment safety. If determined to be a Level 1 fault, the DSP immediately performs a shutdown operation to block energy transfer and prevent the equipment from continuing to operate in a high-risk state. If determined to be a Level 2 fault, the DSP activates a power reduction and early warning mechanism to reduce equipment load while maintaining basic system operation, and provides a visual feedback window for operators. Simultaneously, the fault status is continuously monitored, and if it is not eliminated within a preset time, the handling level is automatically escalated. This ensures that serious faults are contained in a timely manner while minor faults allow the system to continue operating.
[0037] In some embodiments, the detection element may be a Hall sensor or a Rogowski coil. When a Hall sensor is used, the sensor's measurement range is 0-50V for voltage and 0-20A for current, with an accuracy class of 0.5, and the output signal is a 4-20mA current signal.
[0038] Understandably, the detection device can be implemented using a Hall sensor or a Rogowski coil. The Hall sensor can employ an open-loop or closed-loop design; the Rogowski coil is a hollow coil current sensor that can be flexible or rigid. Specifically, when using a Hall sensor, its measurement range refers to the voltage and current range that the sensor can accurately measure, ensuring the accurate acquisition of basic data such as voltage and current. In eddy current loss detection mode or wireless power supply mode, the detection device selects either a Hall sensor or a Rogowski coil based on the operating mode. The former is suitable for stable low-frequency measurements, while the latter is suitable for high-frequency electromagnetic environments, thus covering a wide excitation range. The measurement range setting prevents signal saturation or accuracy attenuation, and the accuracy level ensures data reliability. The 4–20mA output signal suppresses noise interference during long-distance transmission, maintaining stability when the analog signal is converted to a digital signal. This data is then used for moving average filtering and status judgment, avoiding misjudgments caused by measurement distortion and improving the reliability and adaptability of the detection.
[0039] Optionally, when selecting a Hall effect sensor for the detection component, the LEM HMSR 25-NP model Hall effect sensor can be used. This sensor has a voltage measurement range of 0–50V and a current measurement range of 0–20A, with an accuracy class of 0.5, and outputs a standard 4–20mA current signal. In actual deployment, this sensor is installed near the metal connector under test, and the output signal is transmitted to the DSP control unit via a shielded cable. This avoids detection errors caused by signal interference or range mismatch in high-frequency electromagnetic environments, thereby improving the accuracy of equipment status judgment.
[0040] In this invention, the terms "embodiment" and "implementation" mean that a specific feature, structure, or characteristic described in connection with an embodiment can be included in at least one embodiment of the invention. The appearance of these phrases in various places in the specification does not necessarily refer to the same embodiment, nor are they independent or alternative embodiments mutually exclusive with other embodiments. Those skilled in the art will understand, explicitly and implicitly, that the embodiments described in this invention can be combined with other embodiments. Furthermore, it should be understood that the features, structures, or characteristics described in the various embodiments of this invention can be arbitrarily combined to form yet another embodiment that does not depart from the spirit and scope of the technical solution of this invention, provided there is no contradiction between them.
[0041] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to the above preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions to the technical solutions of the present invention should not depart from the spirit and scope of the technical solutions of the present invention.
Claims
1. A method for detecting eddy current loss in metal parts, characterized in that, Includes the following steps: Connect the test piece to the device under test, initialize the device configuration, and select either eddy current loss detection mode or wireless power supply mode. Configure the scanning frequency band parameters or power output reference parameters according to the currently selected mode. Command transmission and parsing: The configuration parameters are converted into RS-485 protocol commands, which are then transmitted to the DSP control unit via the RS-485 communication module. After receiving the commands, the DSP control unit parses them to identify the working mode and the corresponding parameters to be acquired. The parameters of the device under test are acquired, and the collected analog signals are converted into digital signals and fed back to the DSP control unit. The collected data is filtered, and the voltage and current data are smoothed using a moving average filtering algorithm, and the parameters are output. The status of the device under test is determined by comparing the output parameters with the preset parameters. If the parameter is greater than the preset value, the device under test is judged to be abnormal, and an alarm is issued or the detection device is shut down.
2. The method for detecting eddy current loss in metal parts according to claim 1, characterized in that, When the eddy current loss detection mode is selected, the starting scan frequency band, step scan frequency band, and ending scan frequency band are configured according to the PRD table, and the number of data points is 10 points / time; If wireless power supply mode is selected, set the power output reference parameters, set the serial port baud rate to 115200, start the timer and put it into data refresh and status polling state.
3. The method for detecting eddy current loss in metal parts according to claim 1, characterized in that, The parameters of the device under test include: voltage, current, and impedance of the device under test; after acquiring the voltage, current, and impedance data, the device under test converts the analog signals into digital signals and feeds them back to the DSP control unit.
4. The method for detecting eddy current loss in metal parts according to claim 1, characterized in that, If it is the eddy current loss detection mode, two time windows, ON and OFF, are constructed in the ePWM2 interrupt. During the ON window, the product of Buck output voltage and current is accumulated. When the OFF window ends, the average power is calculated to obtain the eddy current loss value at each frequency point.
5. The method for detecting eddy current loss in metal parts according to claim 1, characterized in that, The filtering process for the collected data includes: creating graphs and tables after receiving the data, comparing the graphs and tables with preset data, and marking anomalies in the graphs and tables.
6. The method for detecting eddy current loss in metal parts according to claim 1, characterized in that, The filtering process for the collected data includes: a data calibration step, which involves calibrating the data using a preset standard resistance load, obtaining calibration coefficients at different frequency points, and multiplying the calculated average power by the calibration coefficients at the corresponding frequency points to obtain the calibrated eddy current loss value.
7. The method for detecting eddy current loss in metal parts according to claim 1, characterized in that, Obtaining parameters of the device under test also includes: In wireless power supply mode, a phase-shifting soft-start strategy is adopted to gradually adjust the phase shift angle of the PWM signal from 0° to the target phase shift angle, with an adjustment step size of 5° / 20ms.
8. The method for detecting eddy current loss in metal parts according to claim 1, characterized in that, The parameters of the device under test also include: if it is an eddy current loss detection mode, a duty cycle ramp-up soft start strategy is adopted, and the duty cycle of the Buck converter is gradually increased from 10% to the target duty cycle at an increase rate of 5% / 10ms.
9. The method for detecting eddy current loss in metal parts according to claim 1, characterized in that, It also includes fault classification and handling strategies; Faults are classified into primary and secondary faults; when a primary fault is detected, the DSP immediately shuts off the inverter drive signal and marks the fault type. When a level 2 fault is detected, the DSP reduces the power output to 50% of the rated power, issues a fault warning, and displays a yellow warning message. If the fault persists for a preset time without being eliminated, it will be upgraded to a level 1 fault.
10. The method for detecting eddy current loss in metal parts according to claim 1, characterized in that, The detection element can be a Hall sensor or a Rogowski coil. When a Hall sensor is used, the sensor's measurement range is 0-50V for voltage and 0-20A for current, with an accuracy class of 0.5 and an output signal of 4-20mA current signal.