A passive rfid temperature measuring device for electrical equipment

Abstract

The utility model discloses a kind of passive RFID temperature measuring devices for electric power equipment, including packaging box, RFID temperature measuring chip, fin and the magnetic mounting mechanism on the outer wall of packaging box, the internal space of packaging box is divided into the first chamber of upper and the second chamber of lower by the fin of transverse arrangement, first chamber inside is closed space, the RFID temperature measuring chip is located on the upper surface of the fin and is in first chamber, heat dissipation hole is equipped on the lateral wall of second chamber, second chamber and heat dissipation hole form heat dissipation channel, so that the heat of RFID temperature measuring chip passes through fin and is emitted through heat dissipation channel.The utility model adopts chamber heat dissipation design, i.

Description

Technical Field

[0001] This utility model belongs to the field of temperature detection technology, and in particular relates to a passive RFID temperature measuring device for power equipment. Background Technology

[0002] Radio Frequency Identification (RFID) temperature measurement technology is an innovative solution combining wireless communication and temperature sensing. It uses passive or active RFID tags with integrated temperature sensors to achieve remote monitoring and data transmission of the temperature of target objects. In the field of power equipment monitoring, RFID temperature measurement devices, due to their advantages of being wire-free, low-maintenance, and highly adaptable, are gradually replacing traditional infrared and fiber optic temperature measurement technologies and are widely used for temperature monitoring of critical heat points such as switchgear contacts and transformer windings. A typical RFID temperature measurement device consists of the following modules: a passive RFID tag (powered by the radio frequency energy emitted by the reader); an integrated temperature sensor such as a thermistor or digital sensor; a reader (sends activation signals and receives temperature data, supporting communication protocols such as Wi-Fi and LoRa); and a data processing platform (for storing, analyzing, and alarming temperature data).

[0003] Chinese invention patent application (publication number CN118936668A) discloses a passive ultra-high frequency RFID temperature measurement device for power equipment, including a package and a temperature measurement chip located inside the package. The package has extended wings with through holes on both sides. The temperature measurement chip includes a radio frequency antenna, a matching network, a radio frequency analog front-end, a temperature sensor, and a digital baseband. The radio frequency antenna is mounted on the matching network to receive electromagnetic wave signals carrying information and energy emitted by a corresponding reader in the power cabinet, and performs impedance matching between the chip and the antenna through the matching network. The radio frequency analog front-end is connected to the matching network, converts the received matched electromagnetic wave signals into energy, and supplies power to the digital baseband and the temperature sensor. The digital baseband is communicatively connected to the temperature sensor and the radio frequency analog front-end, respectively, to acquire the information carried by the received electromagnetic wave signals, control the temperature sensor to perform encoding / decoding and equipment temperature measurement operations based on the carried information, and transmits the measured equipment temperature to the radio frequency analog front-end, which then sends it to an external reader via the radio frequency antenna.

[0004] However, the above technical solution has the following defects: the temperature measuring chip is packaged with ordinary plastic material and does not involve heat dissipation structure, which leads to significant temperature rise of the chip in high temperature environment >100℃, causing sensor thermal drift. The nominal temperature measurement error is ±1℃, but the actual measured error expands to ±3.5% under 120℃ conditions, making it impossible to accurately identify early heating defects. Utility Model Content

[0005] The purpose of this invention is to provide a passive RFID temperature measurement device for power equipment that is simple in structure, low in cost, has good heat dissipation, small temperature measurement error, and can accurately identify early heating defects.

[0006] The purpose of this utility model is achieved through the following technical measures: A passive RFID temperature measuring device for power equipment, characterized in that it includes a packaging box, an RFID temperature measuring chip, a heat sink, and a magnetic mounting mechanism disposed on the outer wall of the packaging box. The internal space of the packaging box is divided into an upper first chamber and a lower second chamber by a horizontally arranged heat sink. The first chamber is a closed space. The RFID temperature measuring chip is disposed on the upper surface of the heat sink and is located in the first chamber. A heat dissipation hole is provided on the side wall of the second chamber. The second chamber and the heat dissipation hole form a heat dissipation channel, so that the heat of the RFID temperature measuring chip is dissipated through the heat sink and through the heat dissipation channel.

[0007] This invention adopts a compartmentalized heat dissipation design, which divides the internal space of the package into a first chamber and a second chamber. The first chamber is used to accommodate the temperature measuring chip, and the second chamber and heat dissipation holes serve as heat dissipation channels. This invention has good heat dissipation and small temperature measurement error, thus enabling accurate identification of early overheating defects.

[0008] In this invention, a fixed frame is provided between the first chamber and the second chamber, and the heat sink is installed on the upper edge of the central through groove of the fixed frame.

[0009] The RFID temperature measurement chip of this invention is composed of an RF antenna, a matching network, an RF analog front-end, a temperature sensor, and a digital baseband integrated on a single chip.

[0010] The temperature sensor described in this invention is encapsulated on a ceramic substrate, and an aerogel heat insulation cavity filled with nano-aerogel material is provided between the radio frequency analog front end and the temperature sensor.

[0011] The radio frequency antenna described in this invention is an anti-metal slot antenna. The radiator of the anti-metal slot antenna is etched on an FR4 substrate. The matching network integrates a digitally adjustable capacitor and adjusts the matching parameters in real time by feeding back environmental impedance data through the digital baseband.

[0012] The heat sink of this invention is made of copper, and a wave-shaped heat dissipation fin is provided on the lower surface of the heat sink. A thermally conductive silicone layer is provided between the RFID temperature measuring chip and the heat sink.

[0013] The heat dissipation fins of this invention extend downward through the through groove of the fixing frame into the second chamber, and the heat dissipation holes are honeycomb-shaped convection holes provided on the opposite side walls of the second chamber.

[0014] This invention provides an ambient temperature sensor on the top surface of the packaging box for dynamically correcting the calculation reference value of the heating state. The ambient temperature sensor is arranged separately from the RFID temperature measurement chip, and the calculation reference value T of the heating state is dynamically corrected through a weighted average algorithm.

[0015] The magnetic mounting mechanism of this utility model includes a magnetic layer, a silicone anti-slip layer, and a U-shaped elastic buckle. The magnetic layer is disposed on the bottom surface of the packaging box, and the silicone anti-slip layer is disposed on the lower surface of the magnetic layer. The bottom sides of the packaging box have extension wings, and through holes are provided on the extension wings. The elastic buckle is embedded in the through holes, and limiting protrusions are provided on the two opposite inner sides of the elastic buckle.

[0016] This utility model provides a magnetic contact on the bottom surface of the packaging box that supports wireless power supply and data transmission. The magnetic contact matches the pre-installed groove on the surface of the device, and the protection level of the magnetic contact is IP67.

[0017] Compared with the prior art, the present invention has the following significant advantages:

[0018] (1) This utility model adopts a cavity heat dissipation design: the internal space of the packaging box is divided into a first cavity and a second cavity. The first cavity is used to accommodate the temperature measuring chip, and the second cavity and heat dissipation holes serve as heat dissipation channels. Thermal interference is blocked by heat sink and aerogel insulation cavity.

[0019] (2) This utility model adopts an anti-metal slot antenna: the radiator is etched on the FR4 substrate, and the matching network integrates a digitally adjustable capacitor to dynamically adapt to the metal environment.

[0020] (3) This utility model adopts a magnetic-elastic composite installation mechanism: the samarium cobalt magnetic layer is combined with the spring steel sheet for buckling, and the vibration resistance is improved to 10g acceleration.

[0021] (4) This utility model adopts dynamic calibration of ambient temperature: an independent ambient temperature sensor corrects the reference value through a weighted algorithm to reduce the false judgment rate. Attached Figure Description

[0022] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0023] Figure 1 This is a three-dimensional structural schematic diagram of the present invention;

[0024] Figure 2 yes Figure 1 Enlarged view of part A in the diagram;

[0025] Figure 3 This is a cross-sectional view of the present invention;

[0026] Figure 4This is an exploded view of the structure of this utility model;

[0027] Figure 5 yes Figure 4 A magnified view of part B in the diagram.

[0028] In the diagram: 1-Encapsulation box, 11-First chamber, 12-Second chamber, 13-Through slot, 14-Fixing frame, 15-Convection hole, 2-Heat sink, 21-Heat sink fin, 22-Thermal conductive silicone layer, 3-Ambient temperature sensor, 4-RFID temperature measuring chip, 6-Magnetic mounting mechanism, 61-Magnetic layer, 62-Elastic buckle, 63-Extension wing, 64-Limiting protrusion, 65-Silicone anti-slip layer, 66-Through hole, 7-Magnetic contact. Detailed Implementation

[0029] like Figures 1-5 As shown, this utility model discloses a passive RFID temperature measuring device for power equipment, including a packaging box 1, an RFID temperature measuring chip 4, a heat sink 2, and a magnetic mounting mechanism 6 disposed on the outer wall of the packaging box 1. The internal space of the packaging box 1 is divided into an upper first chamber 11 and a lower second chamber 12 by the horizontally arranged heat sink 2. The first chamber 11 is a closed space specifically for accommodating the RFID temperature measuring chip 4, achieving electromagnetic shielding. The RFID temperature measuring chip 4 is attached to the upper surface of the heat sink 2 and is located in the first chamber 11. Heat dissipation holes are provided on the side wall of the second chamber 12. The second chamber 12 and the heat dissipation holes form a heat dissipation channel, allowing the heat of the RFID temperature measuring chip 4 to be dissipated through the heat sink 2 and the heat dissipation channel.

[0030] In this embodiment, a fixing frame 14 is provided between the first chamber 11 and the second chamber 12, and the heat sink 2 is installed on the upper edge of the central through groove 13 of the fixing frame 14. The outer edge of the fixing frame 14 is located between the first chamber 11 and the second chamber 12.

[0031] Compared with the traditional single-cavity design, this invention reduces the operating temperature of the temperature sensor by 35-40%, reduces radio frequency signal interference by more than 60%, and improves the temperature measurement stability by two orders of magnitude at an ambient temperature of 120℃.

[0032] The RFID temperature measurement chip 4 integrates an RF antenna, a matching network, an RF analog front-end, a temperature sensor, and a digital baseband onto a single chip. The interconnections between these electrical components are existing technology and will not be elaborated here. Compared to discrete component solutions, this invention improves the response speed from 200ms to 80ms, a 150% increase; reduces signal transmission loss from 3.2dB to 0.8dB, improving signal quality by 300%; and reduces overall power consumption from 2μW to 1.2μW, improving energy efficiency by 40% and significantly extending equipment lifespan. The temperature sensor is encapsulated on a ceramic substrate, and an aerogel insulation cavity filled with nano-aerogel material is provided between the RF analog front-end and the temperature sensor. The aerogel insulation cavity blocks heat conduction from the RF circuit, and together with the ceramic substrate encapsulating the temperature sensor, a dual thermal isolation system is constructed. Test data shows that the impact of the radio frequency circuit on the temperature sensor is reduced by 92%; in the high temperature range of 85-120℃, the temperature measurement error is significantly reduced from ±2.5℃ to ±0.8℃; after 5000 temperature cycle tests, the drift is still less than 0.3℃, and the long-term stability far exceeds that of traditional solutions.

[0033] The RF antenna is an anti-metal slotted antenna, with its radiator etched onto an FR4 substrate. The matching network integrates a digitally adjustable capacitor, adjusting the matching parameters in real time based on environmental impedance data fed back from the digital baseband. The anti-metal slotted antenna design, combined with the digitally adjustable matching network, achieves dynamic impedance matching. When applied to metal surfaces, the communication distance is increased from 0.8m in traditional solutions to 3.5m, a 337% improvement; the signal standing wave ratio (VSWR) is optimized from 3.1 to 1.25, significantly improving signal stability; the automatic impedance adjustment response time is less than 50ms, demonstrating strong environmental adaptability.

[0034] The heat sink is made of copper, and its lower surface has wavy heat dissipation fins 21. A thermally conductive silicone layer 22 is placed between the RFID temperature measuring chip 4 and the heat sink 2, forming a gradient heat dissipation system. The copper heat sink 2 establishes an efficient heat conduction path, and the wavy heat dissipation fins 21 increase the heat dissipation area. The thermally conductive silicone layer 22 fills the microscopic gaps and reduces the contact thermal resistance. The heat dissipation fins 21 extend downward through the through slot 13 of the fixing frame 14 into the second chamber 12. The heat dissipation holes are honeycomb-shaped convection holes 15 set on the opposite side walls of the second chamber 12. The heat dissipation fins 21 extend into the second chamber 12, forming a complete heat dissipation path with the honeycomb-shaped convection holes 15, improving the natural convection heat dissipation capacity by 180%. The unique honeycomb hole structure reduces dust deposition by 85%, solving the problem of easy clogging of traditional heat dissipation holes. The temperature gradient of the second chamber is less than 2℃ / cm, ensuring heat dissipation uniformity.

[0035] An ambient temperature sensor 3 is installed on the top surface of the packaging box 1 to dynamically correct the baseline value for calculating the heating state. The ambient temperature sensor 3 is arranged separately from the RFID temperature measurement chip 4, and the baseline value T for calculating the heating state is dynamically corrected through a weighted average algorithm. The system temperature measurement error is reduced by 65%, and the accuracy of abnormal temperature identification reaches 99.3%; the compensation algorithm calculation time is less than 5ms, which is 8 times faster than traditional solutions; and stable performance is maintained within a wide temperature range of -40℃ to 120℃.

[0036] The magnetic mounting mechanism 6 includes a magnetic layer 61, a silicone anti-slip layer 65, and a U-shaped elastic buckle 62. The magnetic layer 61 uses a samarium cobalt permanent magnet and is located on the bottom surface of the packaging box 1. The silicone anti-slip layer 62 is located on the lower surface of the magnetic layer 61. The magnetic layer 61 and the silicone anti-slip layer have a friction coefficient ≥0.8, and the magnetic attraction force is ≥3N / cm. 2 While maintaining 0.05mm-level precise positioning, it resolves the contradiction between "adhesive force and positioning accuracy" in traditional magnetic mounting. The bottom of the packaging box 1 has two extension wings 63 on both sides, with through holes 66 on the extension wings 63. The elastic buckle 62, made of spring steel sheet, is embedded in the through holes of the extension wings 63. Limiting protrusions 64 are provided on two opposite inner surfaces of the elastic buckle 62. The preload of the spring steel sheet elastic buckle 62 is adjustable from 5-10N, and the limiting protrusions 64 form a three-stage buffer structure for axial / radial / torsional movement.

[0037] A magnetic contact 7 that supports wireless power supply and data transmission is provided on the bottom surface of the packaging box 1. The magnetic contact 7 is adapted to the pre-installed groove on the surface of the device, and the protection level of the magnetic contact 7 is IP67.

[0038] The magnetic mounting mechanism 6, together with the elastic snap 62 and magnetic contact 7, forms a rapid installation system. Installation time is reduced from 5 minutes to 20 seconds, increasing efficiency by 1500%; vibration resistance is tested with 15g acceleration; contact resistance is less than 8mΩ and performance remains stable after 1000 insertions and removals; IP67 protection rating adapts to various harsh environments.

[0039] The specific embodiments described herein are merely illustrative examples illustrating the spirit of this utility model. Those skilled in the art to which this utility model pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of this utility model or exceeding the scope defined by the appended claims.

Claims

1. A passive RFID temperature measuring device for power equipment, characterized in that: The device includes a packaging box, an RFID temperature measuring chip, a heat sink, and a magnetic mounting mechanism disposed on the outer wall of the packaging box. The internal space of the packaging box is divided into an upper first chamber and a lower second chamber by a horizontally arranged heat sink. The first chamber is an enclosed space. The RFID temperature measuring chip is disposed on the upper surface of the heat sink and is located in the first chamber. The side wall of the second chamber is provided with heat dissipation holes. The second chamber and the heat dissipation holes form a heat dissipation channel, so that the heat of the RFID temperature measuring chip is dissipated through the heat sink and through the heat dissipation channel.

2. The passive RFID temperature measuring device for power equipment according to claim 1, characterized in that: A fixing frame is provided between the first chamber and the second chamber, and the heat sink is installed on the upper edge of the central through groove of the fixing frame.

3. The passive RFID temperature measuring device for power equipment according to claim 2, characterized in that: The RFID temperature measurement chip consists of an RF antenna, a matching network, an RF analog front-end, a temperature sensor, and a digital baseband integrated on a single chip.

4. The passive RFID temperature measuring device for power equipment according to claim 3, characterized in that: The temperature sensor is encapsulated on a ceramic substrate, and an aerogel heat insulation cavity filled with nano-aerogel material is provided between the radio frequency analog front end and the temperature sensor.

5. The passive RFID temperature measuring device for power equipment according to claim 4, characterized in that: The radio frequency antenna is an anti-metal slot antenna, and the radiator of the anti-metal slot antenna is etched on the FR4 substrate; the matching network integrates a digitally adjustable capacitor, and adjusts the matching parameters in real time through digital baseband feedback of environmental impedance data.

6. The passive RFID temperature measuring device for power equipment according to claim 5, characterized in that: The heat sink is made of copper, and wavy heat dissipation fins are provided on the lower surface of the heat sink. A thermally conductive silicone layer is provided between the RFID temperature measuring chip and the heat sink.

7. The passive RFID temperature measuring device for power equipment according to claim 6, characterized in that: The heat dissipation fins extend downward through the through slot of the fixing frame into the second chamber, and the heat dissipation holes are honeycomb-shaped convection holes provided on the opposite side walls of the second chamber.

8. The passive RFID temperature measuring device for power equipment according to claim 7, characterized in that: An ambient temperature sensor is provided on the top surface of the package for dynamically correcting the reference value for calculating the heating state.

9. The passive RFID temperature measuring device for power equipment according to claim 8, characterized in that: The magnetic mounting mechanism includes a magnetic layer, a silicone anti-slip layer, and a U-shaped elastic buckle. The magnetic layer is disposed on the bottom surface of the packaging box, and the silicone anti-slip layer is disposed on the lower surface of the magnetic layer. The bottom sides of the packaging box have extension wings, and through holes are provided on the extension wings. The elastic buckle is embedded in the through holes, and limiting protrusions are provided on the two opposite inner sides of the elastic buckle.

10. The passive RFID temperature measuring device for power equipment according to claim 9, characterized in that: The bottom surface of the packaging box is provided with magnetic contacts that support wireless power supply and data transmission. The magnetic contacts are adapted to the pre-installed grooves on the surface of the device, and the protection level of the magnetic contacts is IP67.

Images