Soft magnetic composite iron core, health monitoring system, diagnosis and early warning method and application

Abstract

The invention provides a soft magnetic composite iron core, a health monitoring system, a diagnosis early warning method and application, and belongs to the technical field of soft magnetic composite iron cores and reliability monitoring. At least one sensor is embedded in the iron core, is used for detecting at least one of temperature, stress, strain or magnetic field intensity, and is coupled with the intelligent iron core health monitoring system to execute the early warning method of the monitoring system. The temperature distribution, mechanical vibration / stress state and magnetic saturation related characteristics in the working process of the iron core can be obtained in real time, characteristic parameters are extracted based on sensing data, health indexes are constructed, and self-diagnosis and early warning of faults such as over-temperature, looseness and local saturation are achieved. Compared with a traditional externally-attached monitoring scheme, the temperature distribution, the stress vibration and the magnetic saturation state of multiple points in the iron core can be accurately obtained, the hot spot recognition and fault pre-judgment accuracy is remarkably improved, the integrated structure of the sensor and the iron core is high in stability, and predictive maintenance can be supported so that the equipment shutdown risk can be reduced.

Description

Technical Field

[0001] This invention relates to the field of soft magnetic composite iron core and reliability monitoring technology, and particularly to soft magnetic composite iron core, health monitoring system, diagnostic and early warning method and application. Specifically, it relates to a soft magnetic composite iron core in which a sensor is embedded inside and the iron core status is perceived, self-diagnosed and early warning is realized based on the sensor data, as well as its preparation method, health monitoring system and diagnostic and early warning method. Background Technology

[0002] Soft magnetic composite cores, with their excellent formability, controllable loss characteristics, and good adaptability to high-frequency and high-power-density designs, have been widely used in various devices such as server power supplies, home appliance power supplies, charging piles, and vehicle power supplies. In these applications with high reliability requirements, the temperature rise, mechanical vibration stress, and magnetic saturation of the core often exhibit a coupled effect: overheating accelerates insulation aging, vibration stress easily induces cracks or structural loosening, and local magnetic saturation leads to a sharp increase in losses and further exacerbates the temperature rise, ultimately causing device failure.

[0003] Existing engineering solutions typically place temperature or current sensors on the outer surface of the iron core, winding pins, or heat sinks, obtaining mostly indirect or averaged data, which is difficult to accurately reflect the true hot spot distribution and stress concentration inside the iron core.

[0004] For example, Chinese patent application CN121077352A proposes a segmented thermal management system for a segmented motor stator core structure. This system places sensors between the cores and calculates the overall heat dissipation index based on the temperature data of each monitoring position of adjacent stator core units, combined with the positional distribution of monitoring points and gaps. By adjusting the actual power of the motor and the liquid flow rate of each characteristic segment stator core unit, a segmented thermal management scheme is formulated.

[0005] For example, Chinese patent application CN208888315U discloses a closed-loop iron core induced current leakage device, which deploys a monitoring unit on the closed-loop iron core to achieve real-time monitoring and reliable feedback.

[0006] Currently, the monitoring of iron cores relies heavily on external sensors, while the magnetic saturation state is mainly determined by circuit-side current estimation or external probe sampling, making it difficult to achieve online, long-term, and distributed monitoring of iron cores.

[0007] Therefore, there is an urgent need to develop an intelligent iron core structure and manufacturing method that can directly and in real time acquire the working status inside the iron core and has self-diagnosis and early warning functions, so as to support the predictive maintenance of the equipment and further improve its operational reliability. Summary of the Invention

[0008] In view of this, to address the technical problems of existing iron cores being imperceptible, externally attached sensors failing to accurately reflect internal hot spots and saturation states, and the difficulty in conducting predictive maintenance, this invention provides a soft magnetic composite iron core, a health monitoring system, a diagnostic and early warning method, and applications. By pre-embedding sensors for temperature, stress, strain, and magnetic field strength before hot-pressing the soft magnetic composite iron core, the internal state of the iron core can be directly sensed through integrated molding. Based on the sensor data, feature parameters are extracted and a health index is constructed to achieve self-diagnosis and early warning of faults such as overheating, loosening, and local saturation. Compared to traditional externally attached monitoring solutions, this invention can accurately acquire multi-point temperature distribution, stress vibration, and magnetic saturation states within the iron core, significantly improving the accuracy of hot spot identification and fault prediction. The integrated structure of the sensors and the iron core offers strong stability and supports predictive maintenance to reduce equipment downtime risks.

[0009] To achieve the above objectives, the present invention provides the following technical solution: In a first aspect, the present invention provides a soft magnetic composite iron core with embedded sensing, wherein at least one sensor is pre-embedded in the iron core, the sensor being used to detect at least one of temperature, stress, strain or magnetic field strength; the sensor is completely enclosed inside the iron core.

[0010] Secondly, the present invention provides a method for preparing the above-mentioned soft magnetic composite iron core with embedded sensing, comprising the following steps: Step (1): Provide soft magnetic powder and form an insulating coating layer on its surface; Step (2): Provide at least one sensor and perform temperature and pressure resistant encapsulation or surface isolation treatment on the sensor; Step (3): Mix the soft magnetic powder with the sensor in a predetermined ratio or lay them in layers, and position the sensor in a predetermined area of ​​the mold. At the same time, pre-set an outgoing channel or a wave-transparent window structure in the mold. Step (4): Hot-press sintering or hot-press curing molding is performed on the filled material to densify or solidify the soft magnetic powder and embed the sensor into the iron core. Step (5): Cool and demold to obtain an intelligent soft magnetic composite iron core with embedded sensing and self-diagnosis functions, and seal the lead-out end and connect or couple it with the external acquisition unit and health monitoring system.

[0011] Thirdly, the present invention provides an intelligent iron core health monitoring system, connected to the aforementioned soft magnetic composite iron core with embedded sensing, comprising: A signal acquisition unit is used to acquire and condition the signals from the sensor. The self-diagnosis unit receives data transmitted by the signal acquisition unit and uses it to calculate state characteristic parameters and health index and generate diagnostic results. The early warning unit, based on the diagnostic results, outputs audible, visual, or communication warnings before an abnormality or risk occurs, and uploads health status data to the host computer, cloud, or device main control system.

[0012] Fourthly, the present invention provides a health diagnosis and early warning method for the above-mentioned intelligent iron core health monitoring system, characterized by comprising the following steps: Step (A): The signal acquisition unit acquires the temperature, stress, strain and / or magnetic field strength signals from the sensor; Step (B): Calculate at least one state characteristic parameter based on the signal acquired by the signal acquisition unit. The state characteristic parameters include: temperature gradient, temperature rise rate, stress cycle count, vibration characteristic frequency, magnetic field peak value, magnetic field harmonic content, or saturation margin index. Step (C): The self-diagnostic unit compares the state characteristic parameters with threshold rules, physical models or data-driven models, outputs the core health index, and determines whether there is a risk of overheating, structural loosening, local saturation, insulation deterioration or crack initiation. Step (D): When the health index is lower than the preset threshold or the risk level reaches the preset level, the early warning unit outputs early warning information and records historical data for predictive maintenance.

[0013] Fifthly, the present invention provides applications of the above-mentioned soft magnetic composite iron core, monitoring system or health diagnosis and early warning method in data center server power supplies, home appliance main control boards, outdoor charging piles, vehicle power supplies, high-frequency reactors or converters.

[0014] Compared with the prior art, the present invention has the following beneficial effects: Precise internal state perception capability: By pre-embedded sensors, data on temperature distribution, stress vibration and magnetic field changes at multiple points inside the iron core can be directly obtained. Compared with traditional external sensors, it can more accurately identify early signs of internal hot spots and local saturation, solving the technical problem that traditional solutions can only obtain surface or indirect average information.

[0015] Multi-dimensional fault early warning coverage: Simultaneously realizes full-dimensional online monitoring of thermal characteristics (overheating, abnormal temperature rise), mechanical structure (loosening, crack initiation), and magnetic properties (local saturation, insulation degradation), and can output early warning before the fault occurs, avoiding the problems of delayed early warning and high false judgment rate of traditional solutions.

[0016] High reliability of integrated structure: The sensor and iron core are integrated by hot pressing and sintering, eliminating the stability risks such as adhesive layer aging and assembly stress of external sensors, making it suitable for long-term stable operation and large-scale mass production.

[0017] Predictive maintenance support: Based on sensor data, health index and fault prediction models are built, which can realize the remaining life assessment and maintenance strategy optimization, upgrading the traditional "post-failure maintenance" mode to "predictive maintenance", significantly reducing equipment downtime risk and operation and maintenance costs.

[0018] Adaptable to complex operating conditions: The sensor can be packaged with temperature and pressure resistance, and the lead-out channel is equipped with a protective sleeve, which can adapt to the long-term monitoring needs of high reliability and complex operating conditions such as data center power supply and outdoor charging pile. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of the intelligent soft magnetic composite iron core of the present invention; Figure 2 This is a process flow diagram of the preparation method of the present invention; Figure 3 This is a schematic diagram of multi-point temperature, stress, and magnetic field distribution data. From top to bottom on the right, the diagrams correspond to the following: temperature distribution diagram - multi-point temperature curve diagram, stress / strain distribution diagram - strain or vibration characteristic diagram, and magnetic field intensity distribution diagram - magnetic field waveform and distortion diagram. Figure 4 This is a schematic diagram of a health diagnosis and early warning process based on sensor data; In the diagram: 1. Iron core; 2. Temperature sensor; 3. Stress and strain sensor; 4. Magnetic field strength sensor or passive resonant tag; 5. Encapsulation layer or isolation layer; 6. Lead-out channel or wire lead-out groove; 7. Inner sleeve of lead-out channel; 8. Wave-transparent window; 9. Data acquisition unit; 10. Magnetic flux direction arrow; 11. Signal transmission direction arrow; 12. Powder insulation coated sintered microstructure; 13. Sensor encapsulation and sleeve cross-section; 14. Insulating coated soft magnetic powder; 15. Sensor; 16. Mixed or layered laying and positioning structure; 17. Limiting groove; 18. Positioning pin; 19. Dissolvable positioning component; 20. Molded intelligent soft magnetic composite iron core; 21. Lead-out end sealing and electrical or optical connection. Detailed Implementation

[0020] 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. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0021] like Figure 1 As shown, this invention provides a soft magnetic composite iron core with embedded sensing. At least one sensor is pre-embedded within the iron core 1. The sensor is used to detect at least one of temperature, stress, strain, or magnetic field strength (e.g., temperature, stress, strain, or magnetic field strength). Figure 3 As shown in the diagram, a schematic diagram of multi-point temperature, stress, and magnetic field distribution data is provided (the sensor is completely encased inside the iron core). The iron core 1 is an integrated structural component formed by hot-pressing sintering or hot-pressing curing of a soft magnetic composite material with an insulating layer. Its powder-insulated sintered microstructure 12 is as follows... Figure 1 As shown.

[0022] The sensors are configured as a multi-point array, distributed along the main path of the iron core flux, near the winding window, and in the expected hot spot area. The spacing between two adjacent sensors is 0.5-20 mm, and the embedment depth of the sensors from the iron core surface is 0.1-5 mm. A temperature- and pressure-resistant protective encapsulation layer or isolation layer 5 is provided outside the sensors. The encapsulation layer or isolation layer 5 is made of SiO2, Al2O3, ZrO2, glass ceramic, mica, or their composite materials, with an encapsulation thickness of 1 μm to 500 μm.

[0023] The preferred sensors are temperature sensors (2), stress / strain sensors (3), magnetic field strength sensors, or passive resonant tags (4), etc. Specifically: The sensor is at least one of the following: fiber Bragg grating sensor, miniature thermocouple, thin-film thermistor, piezoelectric sensor, resistance strain gauge, magnetoresistive sensor, Hall magnetic field sensor, low-frequency RFID tag based on magnetic coupling, or resonant passive tag.

[0024] The sensor connects or couples with the signal acquisition unit 9 outside the iron core via a pre-set lead-out channel or wire lead-out groove 6, fiber optic lead-out hole, or electromagnetic coupling transparent window 8. An inner sleeve 7, such as a ceramic sleeve, glass sleeve, or heat-resistant polymer sleeve, is installed inside the lead-out channel or wire lead-out groove 6 to reduce the stress on the sensor and lead-out parts caused by molding shrinkage. A schematic diagram of the sensor package and sleeve cross-section 13 is shown below. Figure 1 As shown.

[0025] like Figure 1 As shown, core 1 is a toroidal soft magnetic composite core, and its magnetic flux direction is as follows. Figure 1 As shown by arrow 10 in the direction of the magnetic flux, the signal transmission between the external signal acquisition unit 9 and the sensor is as follows: The left-side signal acquisition unit 9 issues a data acquisition command. After receiving the command, the internal sensor of the iron core sends the acquired data to the right-side signal acquisition unit 9 in the form of a signal, such as... Figure 1 The signal transmission direction is shown by arrow 11 in the diagram.

[0026] like Figure 2 As shown, the present invention provides a method for preparing the above-mentioned soft magnetic composite iron core with embedded sensing, comprising the following steps: Step (1): Provide soft magnetic powder and form an insulating coating layer on its surface, such as... Figure 2The insulating coated soft magnetic powder 14 is shown. In step (1), the soft magnetic powder is preferably Fe-Si alloy powder, Fe-Si-Al powder, Fe-Ni powder, Fe-Co powder, iron-based amorphous powder, nanocrystalline powder or a mixture thereof; the insulating coating layer is SiO2, Al2O3, MgO, phosphate, silicate or a composite insulating layer thereof, and the thickness of the insulating layer is 10nm~1000nm.

[0027] Step (2): Provide at least one sensor 15, and perform temperature and pressure resistant encapsulation or surface isolation treatment on the sensor 15, such as... Figure 2 The encapsulation layer or isolation layer 5 is shown. The encapsulation material is preferably silicon dioxide, alumina, zirconium oxide, glass ceramic, mica or its composite material, etc.; the thickness is 1μm to 500μm.

[0028] Step (3): Mix the soft magnetic powder with the sensor in a predetermined ratio or layer them (e.g., Figure 2 As shown, the mixing or layering is achieved through the mixing or layering and positioning structure 16, and the sensor 15 is positioned in the predetermined area of ​​the mold. At the same time, the mold has pre-set structures such as lead-out channels or wire lead-out grooves 6 and wave-transparent windows 8. In this step (3), the mixing methods include: mixing the sensor with soft magnetic powder by roller mixing, dispersion mixing or slurry mixing and drying; or using a layered powder laying method to embed the sensor at different heights; and using the limiting groove 17, positioning pin 18, soluble positioning part 19 or 3D printed sacrificial core to achieve the spatial positioning of the sensor 15.

[0029] Step (4) involves hot-pressing or hot-pressing curing the filled material to densify or solidify the soft magnetic powder and embed the sensor entirely into the iron core. In step (4), hot-pressing is performed under a protective atmosphere or vacuum, with the protective atmosphere being nitrogen or argon. The hot-pressing process parameters are: sintering temperature of 450-550℃, applied pressure of 50-600MPa, and holding time of 1-10min; or the hot-pressing curing temperature of 120-300℃, pressure of 50-800MPa, and holding time of 1-60min. The heating process includes: first heating to an intermediate temperature at a first heating rate and holding to remove volatiles or complete resin pre-curing, and then heating to the final molding temperature at a second heating rate; the first heating rate is 1-30℃ / min, and the second heating rate is 1-50℃ / min.

[0030] Step (5) Cooling and demolding yields an intelligent soft magnetic composite iron core with embedded sensing and self-diagnostic functions (such as...). Figure 2 The molded intelligent soft magnetic composite iron core 20 shown is then sealed at the lead-out end and connected or coupled to an external acquisition unit and health monitoring system (e.g., Figure 2The lead-out end is sealed and connected to the electrical or optical connection 21.

[0031] like Figure 4 As shown, the present invention also provides an intelligent iron core health monitoring system, which is connected to the above-mentioned soft magnetic composite iron core with embedded sensors, characterized in that it includes: The signal acquisition unit is used to acquire the signals from the sensor and condition them (e.g., filter).

[0032] The self-diagnostic unit receives data transmitted by the signal acquisition unit, and uses it to calculate state characteristic parameters and health index and generate diagnostic results.

[0033] The early warning unit, based on the diagnostic results, outputs audible, visual, or communication warnings before an abnormality or risk occurs, and uploads health status data to the host computer, cloud, or device main control system.

[0034] This invention also provides a health diagnosis and early warning method for the above-mentioned intelligent iron core health monitoring system, comprising the following steps: Step (A): The signal acquisition unit acquires the temperature, stress, strain and / or magnetic field strength signals from the sensor.

[0035] Step (B): Calculate at least one state characteristic parameter based on the signal acquired by the signal acquisition unit. State characteristic parameters include: temperature gradient, temperature rise rate, stress cycle count, vibration characteristic frequency, magnetic field peak value, magnetic field harmonic content, or saturation margin index. The saturation margin index is obtained by jointly calculating the magnetic field strength signal and the input current / voltage signal, or by calculating the peak value of the magnetic field strength signal, waveform distortion coefficient, and temperature compensation parameters, to characterize the degree to which the iron core approaches magnetic saturation.

[0036] Step (C): The self-diagnostic unit compares the state characteristic parameters with threshold rules, physical models, or data-driven models, outputs the core health index, and determines whether there is a risk of overheating, structural loosening, local saturation, insulation degradation, or crack initiation. The data-driven model is a regression model, Bayesian model, support vector machine model, neural network model, or an ensemble model thereof; the physical model includes at least one of the following: core loss-temperature rise model, thermal resistance network model, or magnetic saturation model.

[0037] Step (D): When the health index is lower than the preset threshold or the risk level reaches the preset level, the early warning unit outputs early warning information and records historical data for predictive maintenance.

[0038] For details of the monitoring system and early warning method provided by this invention, please refer to [link / reference needed]. Figure 4 The content shown.

[0039] This invention also provides applications of the aforementioned soft magnetic composite iron core, monitoring system, or health diagnosis and early warning method in data center server power supplies, home appliance main control boards, outdoor charging piles, vehicle power supplies, high-frequency reactors, or converters, enabling direct perception of the internal state of the iron core and early warning of faults. It can accurately identify internal hot spots, structural loosening, and local saturation risks, support predictive maintenance, and adapt to high reliability and complex operating conditions.

[0040] The technical solution of the present invention will be clearly and thoroughly described below with reference to specific embodiments.

[0041] Example 1 Fabrication and Online Monitoring of FBG-Based Embedded Temperature and Strain Smart Core Raw material preparation: Provide iron-based soft magnetic powder or Fe-Si alloy powder with an average particle size D50 of 10μm-80μm, and form a SiO2 or phosphate insulating layer on its surface with an insulating layer thickness of 50nm-300nm.

[0042] Sensor preparation: Fiber Bragg gratings (FBGs) are selected as temperature and strain sensors. The FBG segments are placed inside SiO2 ceramic micro-sleeves, and glass glaze is applied to both ends of the sleeves to form a temperature and pressure resistant sensor assembly.

[0043] Embedding and molding: Soft magnetic powder is filled into the lower layer of the mold, FBG sensor components are laid and placed near the winding window and the expected hot spot area, and then powder filling is continued to cover; fiber optic lead-out holes are set on the side wall of the mold and ceramic guide sleeves are pre-embedded.

[0044] Hot pressing is performed under nitrogen or argon protection: when hot pressing sintering is used, the sintering temperature is 500℃, the pressure is 300MPa, and the holding time is 4min.

[0045] After cooling and demolding, an embedded FBG smart iron core is obtained.

[0046] The lead-out end of the embedded FBG smart iron core is sealed and connected or coupled to the external acquisition unit and health monitoring system.

[0047] When a rapid temperature rise occurs inside the embedded FBG smart iron core, its sensors convert the abnormal data into a temperature signal and send it to the signal acquisition unit. The signal acquisition unit converts the temperature signal into temperature gradient characteristic parameters. The self-diagnosis unit compares the received status characteristic parameters with the specified temperature threshold, outputs the iron core health index, and determines that the iron core is at risk of overheating. Based on the result of the overheating risk, the early warning unit outputs early warning information to the host computer and records historical data. Based on the early warning information in the host computer, the staff determines whether the equipment needs to be shut down.

[0048] Example 2 Fabrication and Online Monitoring of Magnetic Field Strength Sensor and Strain Smart Iron Core Based on Temperature-Resistant Packaging Raw material preparation: Provide iron-based soft magnetic powder or Fe-Si alloy powder with an average particle size D50 of 10μm-80μm, and form a SiO2 or phosphate insulating layer on its surface with an insulating layer thickness of 50nm-300nm.

[0049] Sensor preparation: A temperature-resistant and encapsulated magnetic field strength sensor is selected as the embedded sensor. The magnetic field strength sensing segment is placed inside a SiO2 ceramic micro-sleeve, and glass glaze is applied to both ends of the sleeve to form a temperature- and pressure-resistant sensor assembly.

[0050] Embedding and molding: Soft magnetic powder is filled into the lower layer of the mold, magnetic field strength sensor components are laid and placed near the winding window and in the high magnetic flux area, and then powder filling and covering are continued; optical fiber lead-out holes are set on the side wall of the mold and ceramic guide sleeves are pre-embedded.

[0051] Hot pressing is performed under nitrogen or argon protection: when hot pressing sintering is used, the sintering temperature is 450℃, the pressure is 400MPa, and the holding time is 5min.

[0052] After cooling and demolding, a smart iron core with an embedded magnetic field strength sensor is obtained.

[0053] The lead-out end of the smart iron core with an embedded magnetic field strength sensor is sealed and connected or coupled to an external acquisition unit and health monitoring system.

[0054] When the magnetic field strength fluctuates inside the intelligent iron core with an embedded magnetic field strength sensor, the sensor converts the abnormal data into a saturation margin index signal and sends it to the signal acquisition unit. The signal acquisition unit converts the saturation margin index signal into characteristic parameters such as local saturation. The self-diagnosis unit compares the received state characteristic parameters with the specified magnetic saturation model, outputs the iron core health index, and determines that the iron core has a risk of oversaturation. Based on the oversaturation risk result, the early warning unit outputs early warning information to the host computer and records historical data. Based on the early warning information in the host computer, the staff determines whether the equipment needs to be shut down.

[0055] Example 3 Fabrication and Online Monitoring of Smart Iron Cores Based on Multi-Sensor Fusion Raw material preparation: Provide iron-based soft magnetic powder or Fe-Si alloy powder with an average particle size D50 of 10μm-80μm, and form a SiO2 or phosphate insulating layer on its surface with an insulating layer thickness of 50nm-300nm.

[0056] Sensor preparation: Temperature sensors, strain and vibration-related sensors, and magnetic field strength sensors are selected as embedded sensors in the iron core.

[0057] Embedding and molding: Soft magnetic powder is filled into the lower layer of the mold, temperature sensors are laid in the hot spot area of ​​the iron core, strain and vibration related sensors are laid in the stress concentration area of ​​the structure, and magnetic field strength sensors are laid in the high magnetic flux area to form a multi-point array, and then powder filling is continued to cover it; fiber optic lead-out holes are set on the side wall of the mold and ceramic guide sleeves are pre-embedded.

[0058] Hot pressing is performed under nitrogen or argon protection: when hot pressing sintering is used, the sintering temperature is 550℃, the pressure is 600MPa, and the holding time is 1min.

[0059] After cooling and demolding, a smart iron core with multi-sensor fusion is obtained.

[0060] The lead-out end of the multi-sensor integrated smart iron core is sealed and connected or coupled to an external acquisition unit and health monitoring system.

[0061] When one or more of the following conditions occur within the intelligent iron core fused by multiple sensors: temperature fluctuations, stress / strain fluctuations, and magnetic field strength fluctuations, the embedded multiple sensors will convert the abnormal data into corresponding signals and send them to the signal acquisition unit. The signal acquisition unit will then convert the fluctuation signals into characteristic parameters such as temperature gradient, temperature rise rate, stress cycle count, vibration characteristic frequency, magnetic field peak value, magnetic field harmonic content, or saturation margin index. The self-diagnosis unit will compare the received state characteristic parameters with the prescribed threshold rules, physical models, or data-driven models, output the iron core health index, and determine whether the iron core has one or more risks, such as overheating, structural loosening, local saturation, insulation degradation, or crack initiation. Based on the risk assessment results, the early warning unit will output early warning information to the host computer and record historical data. Based on the early warning information in the host computer, the staff will determine whether it is necessary to shut down the equipment.

[0062] Comparative Example 1 Traditional soft magnetic composite iron core without embedded sensors Using the same soft magnetic powder and hot pressing process as in Example 1, but without embedding any sensors, a traditional soft magnetic composite iron core was obtained.

[0063] Comparative tests show that under medium- and high-frequency operating conditions, iron cores prepared using traditional methods can only obtain information on the outer surface temperature and circuit-side current, failing to identify early signs of internal hot spots and local saturation. This results in delayed warnings and a high false alarm rate. In contrast, intelligent iron cores equipped with multi-sensor fusion can identify signs of internal hot spots and local saturation earlier, thus issuing early warnings.

[0064] Comparative Example 2 External sensor solution Monitoring is typically performed by attaching thermistors or strain gauges to the outer surface of a soft magnetic composite iron core. However, due to thermal resistance from the core's interior to the surface and interface errors, the externally attached sensors exhibit response lag. Furthermore, the externally attached strain gauges are susceptible to adhesive aging and assembly stress, resulting in insufficient long-term stability. Compared to the embedded sensing method of this invention, the externally attached approach struggles to achieve multi-point distributed monitoring and long-term reliable diagnostics.

[0065] In summary, this invention, by pre-embedding micro-sensors before forming the soft magnetic composite iron core and achieving integrated forming, enables the iron core to possess internal state sensing and self-diagnostic capabilities, which can significantly improve the online monitoring and predictive maintenance capabilities of high-reliability power electronic devices.

[0066] The above description is merely a preferred embodiment of the present invention. However, the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention should be covered within the scope of protection of the present invention.

Claims

1. A soft magnetic composite iron core with embedded sensing, characterized in that, At least one sensor is pre-embedded inside the iron core, and the sensor is used to detect at least one of temperature, stress, strain or magnetic field strength; the sensor is completely enclosed inside the iron core.

2. The soft magnetic composite iron core with embedded sensing according to claim 1, characterized in that, The sensors are configured as a multi-point array, distributed along the main path of the iron core flux, near the winding window, and in the expected hot spot area.

3. The soft magnetic composite iron core with embedded sensing according to claim 1, characterized in that, The sensor is at least one of the following: fiber Bragg grating sensor, miniature thermocouple, thin-film thermistor, piezoelectric sensor, resistance strain gauge, magnetoresistive sensor, Hall magnetic field sensor, low-frequency RFID tag based on magnetic coupling, or resonant passive tag.

4. A soft magnetic composite iron core with embedded sensing according to claim 1, characterized in that, The sensor is externally protected with a temperature- and pressure-resistant encapsulation layer or isolation layer.

5. A soft magnetic composite iron core with embedded sensing according to claim 4, characterized in that, The protective encapsulation layer is made of SiO2, Al2O3, ZrO2, glass ceramic, mica, or a composite material thereof, and the encapsulation thickness is 1μm~500μm.

6. A soft magnetic composite iron core with embedded sensing according to claim 1, characterized in that, The spacing between two adjacent sensors is 0.5-20mm, and the embedment depth of the sensor from the iron core surface is 0.1-5mm.

7. A method for preparing a soft magnetic composite iron core with embedded sensing according to any one of claims 1-6, characterized in that, Includes the following steps: Step (1): Provide soft magnetic powder and form an insulating coating layer on its surface; Step (2): Provide at least one sensor and perform temperature and pressure resistant encapsulation or surface isolation treatment on the sensor; Step (3): Mix the soft magnetic powder with the sensor in a predetermined ratio or lay them in layers, and position the sensor in a predetermined area of ​​the mold. At the same time, pre-set an outgoing channel or a wave-transparent window structure in the mold. Step (4): Hot-press sintering or hot-press curing molding is performed on the filled material to densify or solidify the soft magnetic powder and embed the sensor into the iron core. Step (5): Cool and demold to obtain an intelligent soft magnetic composite iron core with embedded sensing and self-diagnosis functions, and seal the lead-out end and connect or couple it with the external acquisition unit and health monitoring system.

8. An intelligent iron core health monitoring system, connected to a soft magnetic composite iron core with embedded sensing as described in any one of claims 1-6, characterized in that, include: A signal acquisition unit is used to acquire and condition the signals from the sensor. The self-diagnosis unit receives data transmitted by the signal acquisition unit and uses it to calculate state characteristic parameters and health index and generate diagnostic results. The early warning unit, based on the diagnostic results, outputs audible, visual, or communication warnings before an abnormality or risk occurs, and uploads health status data to the host computer, cloud, or device main control system.

9. The health diagnosis and early warning method of the intelligent iron core health monitoring system according to claim 8, characterized in that, Includes the following steps: Step (A): The signal acquisition unit acquires the temperature, stress, strain and / or magnetic field strength signals from the sensor; Step (B): Calculate at least one state characteristic parameter based on the signal acquired by the signal acquisition unit. The state characteristic parameters include: temperature gradient, temperature rise rate, stress cycle count, vibration characteristic frequency, magnetic field peak value, magnetic field harmonic content, or saturation margin index. Step (C): The self-diagnostic unit compares the state characteristic parameters with threshold rules, physical models or data-driven models, outputs the core health index, and determines whether there is a risk of overheating, structural loosening, local saturation, insulation deterioration or crack initiation. Step (D): When the health index is lower than the preset threshold or the risk level reaches the preset level, the early warning unit outputs early warning information and records historical data for predictive maintenance.

10. The application of the soft magnetic composite iron core according to any one of claims 1-6, the monitoring system according to claim 8, or the health diagnosis and early warning method according to claim 9 in data center server power supplies, home appliance main control boards, outdoor charging piles, vehicle power supplies, high-frequency reactors, or converters.

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