Sensor micro energy storage system based on power frequency induction electricity taking and use method thereof

Abstract

The invention discloses a sensor micro energy storage system based on power frequency induction electricity taking and a use method thereof, and relates to the technical field of energy collection and micro energy storage. The system comprises an energy acquisition module, an energy conversion module, an energy storage module, a self-starting control module and a load adaptation module. Different electromagnetic field environments are adapted through the dual-mode design of the hollow coil and the small electricity-taking winding, efficient energy conversion and stable power supply are achieved through half-wave rectification, chip capacitor energy storage and a PID algorithm, and the energy supply and demand contradiction is solved in combination with an intermittent working mechanism. The system does not need to depend on a traditional battery, is convenient to install, adapts to extreme working conditions, can remarkably improve the cruising ability and reliability of an intelligent power grid sensor, reduces the maintenance cost, and has good environmental protection and economic benefits.

Description

Technical Field

[0001] This invention relates to the field of power electronics technology, and in particular to a sensor micro-energy storage system based on power frequency induction, which is mainly used to provide a stable and reliable power supply for various sensors, such as power parameter monitoring sensors in smart grids and status monitoring sensors on industrial automated production lines. Background Technology

[0002] In the global energy structure's transition towards cleaner and smarter energy, smart grids and microgrids, as core infrastructure integrating renewable energy, rely on real-time monitoring by large-scale distributed sensors for stable operation. According to IDC forecasts, the number of connected IoT devices globally will exceed 40 billion by 2025, with power system monitoring nodes accounting for over 15%. These sensors are widely distributed across transmission lines, substations, transformers, and other equipment, posing a significant challenge to traditional power supply methods.

[0003] Currently, the mainstream power supply solutions for sensors include wired power supply and battery power supply. Wired power supply requires laying cables, which is extremely costly to install in scenarios such as high-voltage equipment and remote areas, and also poses a risk of electromagnetic interference. While battery power supply offers flexible deployment, its lifespan is typically only 2-3 years, and replacement and maintenance costs are high. Taking my country's smart grid as an example, if the monitoring nodes of approximately 10 million substations nationwide were powered by batteries, 50 million batteries would be consumed annually. This would not only lead to heavy metal pollution but also require a significant investment of manpower for replacement, and even pose safety hazards in special areas such as mountains and deserts.

[0004] Power frequency induction power extraction technology, as a novel self-powered solution, extracts energy from the power frequency electromagnetic field surrounding transmission lines or equipment through the principle of electromagnetic induction, eliminating the need for an external power source and becoming a key direction for solving the power supply problem of sensors. However, existing technologies have the following significant drawbacks:

[0005] First, energy harvesting efficiency is low and adaptability is poor. Traditional energy harvesting coil designs often employ a single structure, making it difficult to adapt to electromagnetic field environments of varying intensities. In weak magnetic field regions, the induced energy is often below the milliwatt level, failing to meet the sensor's startup requirements; while in strong magnetic field environments, magnetic saturation easily leads to a sharp drop in energy conversion efficiency. Studies have shown that when the coil has fewer than 30 turns, the energy storage voltage is often below 2V, failing to trigger system startup.

[0006] Secondly, the energy supply and demand imbalance is significant. Sensors experience instantaneous high power consumption during wireless transmission, while the power output from power frequency induction is typically low continuously, resulting in poor matching. If the energy storage module capacity is improperly designed, problems such as "energy overflow" or "power outage" can easily occur. Traditional lead-acid battery or electrolytic capacitor energy storage solutions are either too large to miniaturize or have excessively high equivalent series resistance, leading to a loss rate exceeding 30%.

[0007] Third, the energy conversion circuit suffers from excessive losses. Rectification and voltage regulation are the main points of energy loss. While full-bridge rectifier circuits have high energy utilization, the cumulative forward voltage drop of the four diodes can reach over 1.5V, resulting in an efficiency of less than 50% in low-voltage scenarios. Half-wave rectification, although simple in structure, suffers from low utilization because it only utilizes half a cycle of energy. Furthermore, the voltage drop power consumption of traditional linear regulators can account for up to 40% of the total losses during input voltage fluctuations.

[0008] Fourth, the system startup and control strategies are inadequate. Existing self-starting circuits mostly employ fixed threshold designs, lacking adaptive adjustment capabilities, and are prone to frequent start-stop phenomena when voltage fluctuates. For example, when the electromagnetic field strength fluctuates due to changes in equipment load, the energy storage voltage may oscillate around the startup threshold, causing sensor malfunctions. Furthermore, most systems do not consider protection mechanisms under extreme operating conditions, making them susceptible to component burnout in overvoltage environments above 380V.

[0009] Fifth, hardware integration and installation are inconvenient. Traditional power supply devices mostly use rigid structures, which are difficult to adapt to curved equipment such as transformers and inductors. Installation requires the disassembly of existing equipment, posing safety risks. According to statistics, the on-site deployment time of existing invasive installation solutions averages more than 30 minutes and may affect the insulation performance of power equipment.

[0010] In summary, existing power frequency induction power harvesting technology has significant shortcomings in terms of energy harvesting adaptability, supply and demand matching, conversion efficiency, control strategies, and ease of installation, which restricts its large-scale application in smart grid sensor power supply. Therefore, developing a high-efficiency, stable, and highly adaptable micro-energy storage system has become an urgent technical problem to be solved.

[0011] The above background information is provided only to aid in understanding the inventive concept and technical solution of this invention. It does not necessarily belong to the prior art of this patent application. In the absence of clear evidence that the above information was disclosed on the filing date of this patent application, the above background information should not be used to evaluate the novelty and inventiveness of this application. Summary of the Invention

[0012] The purpose of this invention is to propose a sensor micro-energy storage system based on power frequency induction and its usage method, so as to solve the technical problems of low energy harvesting efficiency, poor adaptability, prominent contradiction between energy supply and demand, and high loss in the conversion and storage links of the existing technology.

[0013] To achieve the above technical objectives, the present invention adopts the following technical solution:

[0014] A sensor-based micro-energy storage system based on power frequency induction power extraction includes: an energy acquisition module, an energy conversion module, an energy storage module, a self-starting control module, a load adaptation module, and an anomaly protection module;

[0015] The output terminal of the energy harvesting module is electrically connected to the input terminal of the energy conversion module, transmitting the harvested AC power to the energy conversion module;

[0016] The output terminal of the energy conversion module is electrically connected to the input terminal of the energy storage module and the detection terminal of the self-starting control module, respectively. The rectified output of the energy conversion module is connected to the energy storage module for energy storage and provides a voltage monitoring signal to the self-starting control module.

[0017] The output terminal of the energy storage module is electrically connected to the input terminal of the self-starting control module, providing working power to the self-starting control module;

[0018] The control terminal of the self-starting control module is electrically connected to the enable terminal of the load adapter module, and the power supply of the load adapter module is controlled by switching the switch on and off.

[0019] The input terminal of the load adapter module is electrically connected to the boost output terminal of the energy conversion module, and supplies power to the external sensor after receiving a stable voltage.

[0020] The abnormal protection module is connected in parallel between the output terminal of the energy conversion module and ground to provide clamp protection against system overvoltage.

[0021] Preferably, the energy harvesting module includes an induction coil and an energy harvesting winding, wherein the induction coil has 40-60 turns and a cross-sectional area of ​​70-90 mm². 2 The output power is ≥130mW under a magnetic field of 0.04-0.06T; the energy harvesting winding is wound on the inductor core, and the number of secondary turns is 40-90.

[0022] Preferably, the induction coil and the energy harvesting winding are connected to the energy conversion module via a flexible PCB, the flexible PCB having a temperature resistance range of -55℃ to 125℃.

[0023] Preferably, the energy conversion module includes a rectifier circuit, a filter circuit, and a boost circuit. The input terminal of the rectifier circuit is electrically connected to the output terminal of the energy harvesting module, and the output terminal is electrically connected to the input terminal of the filter circuit. The output terminal of the filter circuit is electrically connected to the input terminal of the energy storage module and the input terminal of the boost circuit. The output terminal of the boost circuit is electrically connected to the input terminal of the load matching module, and the control terminal of the boost circuit is electrically connected to the signal output terminal of the self-starting control module. The rectifier circuit uses a Schottky diode with a forward voltage drop ≤0.4V. The filter circuit uses a 5-15nF capacitor. The boost circuit is a Boost converter operating in DCM mode, including a 400-500μH inductor and a switching transistor with an on-resistance ≤30mΩ, and a switching frequency of 20-30kHz.

[0024] Preferably, the energy storage module uses multiple surface-mount capacitors connected in parallel to form an 1800-2400μF energy storage unit. The equivalent series resistance of the surface-mount capacitors is ≤0.15Ω, and the operating temperature range is -55℃ to 125℃. The input terminal of the energy storage module is electrically connected to the output terminal of the filter circuit in the energy conversion module, and the output terminal is electrically connected to the voltage sampling terminal of the self-starting control module.

[0025] Preferably, the self-starting control module includes a voltage monitoring chip, a resistor divider network, a switching transistor, and an intermittent operating mode. The input terminal of the resistor divider network is electrically connected to the output terminal of the energy storage module, and the output terminal is electrically connected to the sampling terminal of the voltage monitoring chip. The output terminal of the voltage monitoring chip is electrically connected to the control electrode of the switching transistor, the input terminal of the switching transistor is electrically connected to the boost output terminal of the energy conversion module, and the output terminal is electrically connected to the power supply terminal of the load adapter module. The voltage monitoring chip has a start-up threshold of 3.0-3.2V and a turn-off threshold of 2.7-2.9V. The standby power consumption of the self-starting control module is ≤200nA. The voltage division ratio of the resistor divider network is 0.4-0.6. The on-resistance of the switching transistor is ≤30mΩ, and the response time is ≤60ms. The power supply cycle of the intermittent operating mode of the self-starting control module is 2.0-2.2 seconds, including a 1.9-2.1 second energy storage stage and a 0.1-0.2 second operating stage, with a peak current of ≤19mA during the operating stage.

[0026] Preferably, the load matching module adopts a PID algorithm with an output voltage of 3.2-3.4V; the load matching module includes a sampling feedback circuit, the input terminal of which is electrically connected to the output terminal of the load matching module, and the output terminal is electrically connected to the input terminal of the PID controller; the sampling feedback circuit adopts a 15-25kΩ resistor voltage divider network; the average power consumption of the system is ≤6mW.

[0027] Preferably, the load adapter module includes an interface conversion circuit, the input terminal of which is electrically connected to the output terminal of the load adapter module, the output terminal is connected to an external sensor, and the integrated communication interface uses a TVS diode for electrostatic discharge protection, with the TVS diode connected in parallel between the signal terminal of the communication interface and ground.

[0028] Preferably, the abnormal protection module includes a clamping circuit consisting of a Zener diode and a 10Ω current-limiting resistor connected in series. The input terminal of the clamping circuit is electrically connected to the boost output terminal of the energy conversion module, and the output terminal is grounded.

[0029] Preferably, the method of using the sensor micro-energy storage system based on power frequency induction includes the following steps:

[0030] (1) Energy harvesting: Select the working mode of the energy harvesting module according to the electromagnetic field environment. In an open strong magnetic field environment, the induction coil is activated to obtain energy by cutting magnetic field lines through 40-60 turns of coil; in a closed weak magnetic field environment, the energy harvesting winding is activated to couple magnetic field energy using 40-90 turns of secondary coil wound on the inductor core. The energy in both modes is output in the form of alternating current.

[0031] (2) Energy conversion: The AC power is processed by the energy conversion module, wherein the rectifier circuit performs half-wave rectification through Schottky diodes to convert the AC power into pulsating DC power, and then the ripple is smoothed by a 5-15nF filter capacitor before being stored in the energy storage module; when the voltage of the energy storage module is lower than 3.2V, the Boost converter operates at a switching frequency of 20-30kHz to boost the voltage to 3.2-3.4V;

[0032] (3) Energy storage and startup: The energy storage module stores energy through multiple surface-mount capacitors connected in parallel. When the voltage reaches the startup threshold of 3.0-3.2V, the voltage monitoring chip of the self-starting control module triggers the switching transistor to turn on, supplying power to the load adapter module and the sensor.

[0033] (4) Intermittent operation: The system enters an intermittent cycle of 2.0-2.2 seconds, of which 1.9-2.1 seconds is the energy storage stage, during which the energy storage module continuously accumulates energy; 0.1-0.2 seconds is the working stage, during which the load adapter module stabilizes the output voltage through the PID algorithm, and the sensor completes data acquisition and transmission. The peak current during the working stage is ≤19mA.

[0034] (5) Hibernation and restart: When the voltage of the energy storage module drops to the shutdown threshold of 2.7-2.9V, the self-starting control module cuts off the power supply, and the system returns to the energy storage stage, repeating steps (3)-(4) in a loop;

[0035] (6) Abnormal protection: When the input voltage is ≥380V, the clamping circuit composed of the Zener diode and the 10Ω current limiting resistor of the abnormal protection module will clamp the output voltage to 3.5V, and at the same time the sensor shortens the warning signal sending interval to 1 second.

[0036] Technical principle:

[0037] 1. Power frequency induction power extraction principle

[0038] According to Faraday's law of electromagnetic induction, when a coil is placed in a power frequency electromagnetic field (50Hz or 60Hz) and cuts magnetic field lines, an induced electromotive force is generated, realizing the conversion of energy from the magnetic field to electrical energy. This system has two energy harvesting methods:

[0039] Air-core coil energy extraction: The air-core coil is directly coupled to an open power frequency electromagnetic field. The induced electromotive force is proportional to the number of coil turns, cross-sectional area and magnetic field strength. It is suitable for open scenarios such as power transmission lines.

[0040] Power extraction via a small winding: The small winding is wound around the inductor core, utilizing the transformer transformation principle formula:

[0041]

[0042] The magnetic field energy inside the coupling device is adapted to a weak magnetic field environment by adjusting the number of turns (N2) on the secondary side.

[0043] 2. Energy Conversion Principle

[0044] Rectification stage: A half-wave rectifier circuit is used, utilizing the unidirectional conductivity of a Schottky diode (such as CUS10S30H3F) to convert alternating current into pulsating direct current. This diode has a forward voltage drop ≤0.37V, which significantly reduces energy loss and improves rectification efficiency compared to ordinary diodes.

[0045] Filtering stage: A 10nF capacitor is connected in the circuit to achieve the filtering function by utilizing the capacitor's charging and discharging characteristics. When the voltage is at its peak, the capacitor stores energy; when the voltage is at its trough, the capacitor releases energy, thereby smoothing the voltage ripple after rectification and ensuring that the output DC voltage fluctuation is ≤50mV, providing a relatively stable DC power supply for subsequent circuits.

[0046] Boost stage: A Boost converter operating in discontinuous conduction mode (DCM) is employed. Based on the principle of inductor energy storage, it controls the energy storage and release process of the inductor through the periodic switching of a switching transistor (AO3400A). When the transistor is on, the inductor stores energy; when the transistor is off, the inductor releases energy and increases the voltage. This Boost converter is equipped with a 470μH inductor and a switching frequency set at 25kHz, capable of stably boosting a low-voltage DC power supply of 13V to 3.3V, meeting the power supply voltage requirements of the sensor.

[0047] 3. Micro-energy storage principle

[0048] The energy storage module, also known as the micro-energy storage module, in this system consists of ten 220μF surface-mount capacitors connected in parallel, with a total capacity of 2200μF. It utilizes the energy storage characteristics of capacitors to temporarily store energy. By carefully selecting surface-mount capacitors with an equivalent series resistance ≤0.1Ω, energy loss during charging and discharging is effectively reduced. Furthermore, these surface-mount capacitors operate within a temperature range of -55℃ to 125℃, maintaining a capacity retention rate of ≥92% at 30℃, ensuring stable energy storage performance even under extreme environmental conditions and precisely matching the energy supply and demand rhythm of the sensor's intermittent operation mode.

[0049] 4. Self-starting and intermittent control principles

[0050] Self-starting mechanism: The voltage of the energy storage capacitor is monitored in real time using the IMP809 voltage monitoring chip. When the voltage reaches the 3.08V start-up threshold, the chip outputs a signal to trigger the MOSFET switch to turn on, thereby supplying power to the load; when the voltage drops to the 2.8V turn-off threshold, the chip controls the MOSFET switch to turn off, and the system enters the energy storage stage. By setting a hysteresis voltage of 0.2-0.3V, frequent start-up and shutdown of the switch due to voltage fluctuations are effectively avoided, ensuring stable system operation.

[0051] Intermittent Operating Mode: Based on precise analysis and dynamic balance of energy harvesting rate and load power consumption, the system is set to a 2.14-second operating cycle, including a 2-second energy storage phase and a 0.14-second operating phase. During the operating phase, it can complete key tasks such as sensor temperature measurement, analog-to-digital conversion, and wireless transmission, with a peak current ≤19mA. During the energy storage phase, the system prioritizes energy accumulation. Once sufficient energy is available, it powers the sensor during the operating phase to meet its high energy consumption requirements for short periods, while effectively reducing the overall system power consumption, with average power consumption controlled at ≤5.38mW.

[0052] 5. Voltage stabilization and abnormal protection principle

[0053] Closed-loop voltage regulation: The sampling feedback circuit in the load adapter module acquires the output voltage in real time through a 20kΩ resistor voltage divider network and feeds it back to the incremental PID algorithm module. Based on the deviation between the feedback voltage and the target voltage, the algorithm dynamically adjusts the PWM duty cycle of the Boost converter to stabilize the output voltage within the range of 3.3V±0.1V, with an output voltage adjustment time ≤50ms, ensuring a stable and reliable power supply for the sensor.

[0054] Abnormal Protection: When the input voltage is ≥380V, the Zener diode ZD1 immediately activates, clamping the output voltage to 3.5V to prevent damage to components in the system from excessive voltage. Simultaneously, the sensor rapidly sends a warning signal, shortening the signal interval to 1 second, to promptly notify the user of any abnormalities and ensure the safe operation of the system and related equipment.

[0055] Functions of each module:

[0056] I. Dual-mode energy harvesting device

[0057] 1. Core Functions

[0058] The energy harvesting module includes a dual-mode energy harvesting device that captures energy from power frequency electromagnetic fields, adapts to electromagnetic field environments of different intensities, and provides raw electrical energy to the system.

[0059] 2. Air coil

[0060] Structure: The coil is wound with silicon steel sheets or ferrite cores, using 50 turns of 0.2mm enameled wire, with a coil cross-sectional area of ​​80mm². 2 It is fixed by a 3D-printed ABS+insulated frame, with frame dimensions of 38×21×4.4mm and insulation strength ≥2kV / mm. The bottom is equipped with an N35 neodymium iron boron magnet, 5mm in diameter and 2mm thick, with an adsorption force ≥2N.

[0061] Working principle: Based on Faraday's law of electromagnetic induction, an induced electromotive force is generated by cutting open electromagnetic field magnetic field lines. The induced electromotive force is proportional to the number of turns, magnetic field strength, and cross-sectional area.

[0062] Performance parameters: Outputs 3.3V / 19.5mA of electrical energy under a 0.05T magnetic field, with a power ≥138.74mW. Supports non-intrusive installation, fixed to the surface of equipment such as power transmission lines and substations via magnetic attraction or insulating adhesive, and is compatible with curved components.

[0063] 3. Power supply winding

[0064] Structure: Winded on a manganese-zinc ferrite core, with 50-80 turns on the secondary side. It forms a transformer-like coupling structure with the original inductor coil and is connected to the energy conversion module via a flexible PCB. The flexible PCB uses a polyimide substrate, is 0.1mm thick, has a temperature range of -55℃ to 125℃, and can be repeatedly bent ≥1000 times on curved surfaces with a curvature radius ≥5mm.

[0065] Working principle: Utilizing the transformer's turns ratio principle, induced alternating current is generated by coupling magnetic field energy from the inductor core. When the number of turns in the primary inductor coil is fixed, the induced voltage under a weak magnetic field is increased by adjusting the number of turns on the secondary side.

[0066] Performance parameters: In a weak magnetic field environment, increasing the number of secondary turns can enable the energy storage module voltage to reach the start-up threshold; it is compatible with curved components such as transformers and inductors, reducing dependence on external electromagnetic fields.

[0067] II. Energy Conversion Module

[0068] 1. Core Functions

[0069] The AC power output from the dual-mode energy harvesting device is converted into stable DC power to supply power to the energy storage module and the load.

[0070] 2. Half-wave rectifier circuit

[0071] Structure: It adopts a single Schottky diode CUS10S30H3F, with a rated voltage of 30V, a rated current of 1A, a forward voltage drop of ≤0.37V, and a package of SOD-323.

[0072] Working principle: Utilizing the unidirectional conductivity of diodes, the diode conducts only during the positive half-cycle of AC, converting AC power into pulsating DC power. Compared to full-bridge rectification, it reduces device losses by 50%, making it more suitable for low-energy applications.

[0073] 3. Filtering circuit

[0074] Structure: Uses 10nF ceramic capacitors, model GRM155R71H103KA01D, 1206 package.

[0075] Working principle: The pulsating DC voltage after rectification is smoothed by the charging and discharging characteristics of the capacitor, suppressing high-frequency ripple and making the output ripple ≤50mV, thus providing a stable input for the subsequent boost circuit.

[0076] 4. Boost converter

[0077] Structure: Operates in discontinuous conduction mode (DCM), including a 470μH inductor (1A saturation current), an AO3400A MOSFET switch (20mΩ on-resistance), an SS14 diode, and a switching frequency of 25kHz.

[0078] Working principle: The voltage is boosted by storing and releasing energy through the inductor, and the switching transistor is periodically turned on and off to boost the 13V low-voltage DC to a stable 3.3V output.

[0079] Performance parameters: The PWM duty cycle can be dynamically adjusted to cope with sudden load changes, the output ripple is <50mV, the settling time is <50ms, and the conversion efficiency reaches 85%.

[0080] III. Micro-energy storage module

[0081] 1. Core Functions

[0082] It temporarily stores energy to balance the intermittent nature of energy harvesting with the pulsed power consumption of the sensor, thus achieving energy buffering.

[0083] 2. Structure

[0084] The energy storage unit consists of 10 surface-mount capacitors connected in parallel. Each capacitor is a GRM31CR60J227ME11L with a capacitance of 220μF, a voltage rating of 6.3V, a 1206 package, and a tolerance of ±20%. The total capacitance is 2200μF, and the equivalent series resistance (ESR) is approximately 0.1Ω (measured at 100kHz).

[0085] 3. Performance parameters

[0086] Wide operating temperature range: -55℃ to 125℃. After 24 hours of testing at 30℃, the capacity retention rate is ≥92%, the ESR increases from 0.1Ω to 0.15Ω, and the charge / discharge efficiency is ≥85%.

[0087] Fast charging and discharging: Supports charging and discharging from 0.65V to 3.3V within a 2.14-second cycle, and can release 11.51mJ of energy in a single energy storage, meeting the sensor's data transmission requirements for 3 times.

[0088] IV. Self-starting control module

[0089] 1. Core Functions

[0090] Monitor the voltage of the energy storage module to enable automatic system startup and hibernation, control energy flow, and reduce standby power consumption.

[0091] 2. Structure

[0092] It includes a voltage monitoring chip IMP809, a resistor divider network (R1 = 51Ω, R2 = 11kΩ), and an AO3400A MOSFET switch.

[0093] 3. Working principle and performance

[0094] Threshold monitoring: The voltage monitoring chip sets a 3.08V start-up threshold and a 2.8V shutdown threshold, with a hysteresis of 0.28V. The energy storage voltage is converted into an input level compatible with the monitoring chip through a resistor divider network.

[0095] Start-stop control: When the energy storage voltage is ≥3.08V, the switching transistor is turned on to supply power to the load adapter module and sensor; when the voltage is ≤2.8V, the switching transistor is turned off to disconnect the load circuit and enter the energy storage stage.

[0096] Low power consumption and responsiveness: The monitoring chip has a standby current of 150nA and a switching response time of ≤50ms. Hysteresis characteristics can suppress frequent start-stop cycles caused by voltage fluctuations, improving system stability.

[0097] V. Load Adaptation Module

[0098] 1. Core Functions

[0099] Stable output voltage, adaptable to dynamic sensor loads, and optimized energy utilization efficiency.

[0100] 2. Structure

[0101] It includes a sampling feedback circuit, an STM32L051 microcontroller, and an interface conversion circuit. The sampling feedback module acquires the output voltage through a 20kΩ resistor voltage divider network (voltage divider ratio 0.5) and a 10nF filter capacitor. Combined with an incremental PID algorithm optimized by displacement multiplication, it reduces the microcontroller's computational power consumption by 2mW and achieves a closed-loop control accuracy of <±0.1%.

[0102] 3. Working principle and performance

[0103] Voltage regulation: The output voltage is acquired through a sampling feedback circuit, and the incremental PID algorithm dynamically adjusts the PWM duty cycle to stabilize the output voltage at 3.3V±0.1V. When the load jumps from 8mA to 19mA, the voltage fluctuation is ≤±0.2V, and the recovery time is ≤50ms.

[0104] Power consumption optimization: The shift multiplication method is used to replace the traditional operation, which reduces the microcontroller's computing power consumption by ≥2mW and the average system power consumption by ≤5.38mW.

[0105] Interface compatibility: Converts 3.3V to a wide voltage range of 9-30V via a DC-DC chip, compatible with the FRTFWS500 five-element weather sensor. Integrated RS485 communication interface, with SMBJ6.5A TVS diodes to suppress electrostatic interference.

[0106] VI. Anomaly Protection Module

[0107] 1. Overvoltage protection

[0108] When the input voltage is ≥380V, the Zener diode ZD1 (3V) and the 10Ω current-limiting resistor are connected in series to form a clamping circuit, clamping the output voltage to 3.5V. At the same time, the sensor sends a warning signal, with the interval shortened from 5 seconds to 1 second.

[0109] 2. Extreme temperature protection

[0110] Low temperature (-55℃): the surface mount capacitor retains 92% of its capacity, the ESR rises to 0.15Ω, and the system maintains stability by extending the energy storage cycle to 2.3 seconds.

[0111] High temperature (125℃): The capacitor leakage current increases to 5μA, the energy storage efficiency decreases to 78%, and the software extends the interval period to 3 seconds before returning to stable operation.

[0112] 3. Electromagnetic compatibility protection

[0113] The air-core coil is equipped with a permalloy magnetic shielding layer, and the drive module introduces an RC high-pass filter (cutoff frequency 5.31Hz) to filter out the DC bias in the PWM signal, so that the DC component of the grid-connected current is less than 0.1% and high-frequency interference is suppressed.

[0114] VII. Collaborative Workflow of Each Module

[0115] 1. Energy Harvesting: The dual-mode harvesting device obtains power frequency electromagnetic field energy through hollow coils or small power-taking windings and outputs alternating current.

[0116] 2. Energy conversion: AC power is converted into DC power after half-wave rectification and filtering, and stored in the micro energy storage module; the Boost converter raises the low voltage to 3.3V as needed.

[0117] 3. Energy storage and startup: When the voltage of the energy storage module rises to 3.08V, the self-starting module activates the load adapter module to power the sensor.

[0118] 4. Operation and Sleep: After the sensor completes temperature measurement and data transmission (peak current 19mA), when the energy storage voltage drops to 2.8V, the system cuts off the power supply and returns to the energy storage stage, forming an intermittent cycle of 2.14 seconds (2 seconds of energy storage + 0.14 seconds of operation).

[0119] 5. Abnormal handling: Under conditions such as overvoltage and extreme temperature, the protection module triggers clamping, alarm, or periodic adjustment to ensure the safe operation of the system.

[0120] The beneficial effects of this invention compared to the prior art include:

[0121] 1. Dual-mode power harvesting design enhances environmental adaptability

[0122] This invention innovatively employs a dual-mode energy harvesting device consisting of a hollow coil and a small power-harvesting winding, overcoming the limitations of traditional single-structure designs. The hollow coil, with its silicon steel core and optimized 50-turn design, achieves an output power of 138.74mW under a 0.05T magnetic field, solving the problem of starting in weak magnetic fields. The small power-harvesting winding directly couples the inductive magnetic field through a transformer principle, improving energy harvesting efficiency compared to the hollow coil under the same magnetic field strength, making it particularly suitable for curved surfaces in enclosed spaces. Experimental data shows that this dual-mode design can cover a magnetic field strength range of 0.03T-0.1T, doubling the adaptability range of existing single-structure designs and meeting the monitoring needs of various power equipment.

[0123] 2. High-efficiency energy storage and conversion systems reduce energy loss.

[0124] This invention significantly reduces energy loss through three levels of optimization: First, it employs a half-wave rectifier circuit with a Schottky diode CUS10S30H3F, achieving a forward voltage drop of only 0.37V, while simultaneously compensating for the low energy utilization of half-wave rectifiers through intermittent operation. Second, the micro-energy storage module uses a parallel design of 2200μF surface-mount capacitors, resulting in an equivalent series resistance (ESR) as low as 0.1Ω, significantly lower than traditional electrolytic capacitors. Third, the Boost converter operates in DCM mode, combining a 470μH inductor and an AO3400A switching transistor, achieving a conversion efficiency of 85%, a 3% improvement over CCM mode, while reducing the inductor size by 2mm. 3 The overall energy conversion efficiency of the system is improved compared to existing technologies, and it can support up to three more sensor data transmissions under the same magnetic field environment.

[0125] 3. Balancing stability and energy efficiency through adaptive self-starting and intermittent control strategies.

[0126] The self-starting control module of this invention employs a hysteresis design with a 3.08V start-up threshold and a 2.8V turn-off threshold. The 0.28V voltage difference effectively avoids frequent start-stop cycles caused by voltage fluctuations, reducing malfunctions by 90% compared to a fixed threshold scheme. The intermittent operating mode achieves energy supply and demand matching through a 2.14-second cycle (2 seconds of energy storage + 0.14 seconds of operation). Under an average load of 19.5mA, a single operation can complete the entire process of temperature measurement and transmission, with an average power consumption of only 5.38mW, lower than the continuous operating mode. The incremental PID algorithm optimizes the calculation process through displacement multiplication, reducing microcontroller power consumption by 2mW. The output voltage adjustment time is ≤50ms, ensuring stable operation of the sensor even at a peak current of 19mA, solving the problems of slow response and high power consumption in traditional control algorithms.

[0127] 4. Non-intrusive installation and protection against extreme conditions enhance practicality.

[0128] This invention employs a magnetic structure and flexible PCB design, allowing direct bonding to curved surfaces such as transformers and inductors. Installation requires no disassembly of existing equipment, reducing deployment time to 5 minutes—a 6-fold improvement over invasive solutions—and avoiding the risk of insulation damage. Under extreme conditions, the system exhibits excellent stability: at -55℃, the surface-mount capacitor retains 92% of its capacitance, higher than electrolytic capacitors; at 125℃, leakage current is controlled below 5μA; and under 380V overvoltage, dual protection through Zener diode clamping and software alarms prevents component damage. Experimental verification shows that the system can operate stably within a temperature range of -55℃ to 125℃, a magnetic field strength of 0.03T to 0.1T, and voltage fluctuations of 100 to 380V, adapting to the complex and variable operating environment of power systems. Attached Figure Description

[0129] Figure 1 This is a prototype that uses a hollow coil as an energy harvesting device;

[0130] Figure 2 This is a prototype that uses a small power-collecting winding as an energy harvesting device;

[0131] Figure 3 This is a physical diagram of the energy management circuit.

[0132] Figure 4 Schematic diagram of a synchronous-Buck converter;

[0133] Figure 5 The waveform diagram for Case 1 experiment;

[0134] Figure 6 The waveform diagram for case two is shown below.

[0135] Figure 7 The waveform diagram for the experiment in scenario two, where the voltage continuously increases.

[0136] in Figure 3 (a) Front view of the power management circuit board; (b) Back view of the power management circuit board; (c) Side view of the power management circuit board;

[0137] Figure 5 Experimental diagram of intermittent working mode in case 1; enlarged waveform diagram of interval b. Detailed Implementation

[0138] I. System Structure and Parameters, Usage Method

[0139] 1. Dual-mode energy harvesting device

[0140] (1) Induction coil

[0141] Coil structure: It is wound with 50 turns of 0.2mm enameled wire and uses a silicon steel sheet core. The core specifications are 30mm outer diameter, 15mm inner diameter, and 10mm height. This core material has high permeability and low coercivity, which can effectively enhance the magnetic field coupling efficiency.

[0142] Cross-sectional area design: The coil cross-sectional area is 80mm. 2 This parameter was determined through finite element simulation optimization. When the cross-sectional area is 60mm... 2 Increased to 80mm 2 At a magnetic field strength of 0.05T, the induced power increased from 97.2mW to 138.74mW, an increase of 42.7%.

[0143] Output performance: Under a magnetic field of 0.05T, the induction coil can output a voltage of 3.3V and a current of 42mA, with a corresponding output power of 138.74mW, which meets the energy requirements for system startup and sensor operation.

[0144] (2) Energy harvesting winding

[0145] Core selection: The core is wound on a manganese-zinc ferrite core with a diameter of 8 mm and a length of 20 mm. Manganese-zinc ferrite material has high initial permeability and is suitable for operation in low-frequency magnetic field environments.

[0146] Turns design: The secondary winding has 70 turns, which provides good energy coupling in typical weak magnetic field environments. When the magnetic field strength is further reduced, the number of turns can be increased to 80 turns to improve the induced voltage.

[0147] Coupling performance: By optimizing the winding structure and core layout, the coupling coefficient of the energy harvesting winding is ≥0.8, ensuring that energy can still be efficiently harvested in a weak magnetic field environment.

[0148] 2. Energy Conversion Module

[0149] (1) Rectifier circuit

[0150] Diode selection: A Schottky diode CUS10S30H3F is used. This diode has a rated voltage of 30V, a rated current of 1A, and an extremely low forward voltage drop of only 0.37V.

[0151] Package type: SOD-323 package is selected. This miniaturized package helps to reduce the size of the circuit board and improve the system integration.

[0152] Rectification topology: It adopts a half-wave rectification topology, which can reduce the number of diodes by 50% compared with the traditional full-bridge rectifier circuit, thereby further reducing conduction losses.

[0153] (2) Filtering circuit

[0154] Capacitor selection: Use a 10nF ceramic capacitor GRM155R71H103KA01D. This capacitor is in a 1206 package and has low ESR and good high-frequency characteristics.

[0155] Filtering effect: It can effectively suppress voltage ripple and control the voltage ripple after rectification within the range of ≤50mV, providing a stable input for the subsequent boost circuit.

[0156] (3) Boost converter

[0157] Inductor parameters: A 470μH power inductor is selected. This inductor has a saturation current of 1A and can maintain a stable inductance value under high current.

[0158] Switch selection: AO3400A MOSFET is used as the switch, with an on-resistance of only 20mΩ, which can significantly reduce switching losses.

[0159] Operating frequency: The switching frequency is set to 25kHz. This frequency selection takes into account both conversion efficiency and component size, ensuring high conversion efficiency while avoiding increased switching losses caused by excessively high frequencies.

[0160] 3. Micro-energy storage module

[0161] (1) Capacitor selection

[0162] The capacitor used is a GRM31CR60J227ME11L surface-mount capacitor, with a single capacitor having a capacitance of 220μF, a rated voltage of 6.3V, and a 1206 package. This capacitor has an extremely low equivalent series resistance (ESR) of only 0.08Ω, which can effectively reduce energy loss during charging and discharging.

[0163] (2) Parallel structure

[0164] Ten of the aforementioned surface-mount capacitors are connected in parallel to form an energy storage unit with a total capacity of 2200μF. This parallel structure not only increases the energy storage capacity but also further reduces the overall ESR, thus improving energy storage efficiency.

[0165] (3) Low temperature characteristics

[0166] At a low temperature of 30℃, the capacitor retains 92.3% of its capacitance, meeting the operational requirements of most harsh environments. After 24 hours of low-temperature testing, the capacitor's charge / discharge efficiency remains ≥85% at 30℃.

[0167] 3. Self-starting control module

[0168] (1) Voltage monitoring chip

[0169] The IMP809 voltage monitoring chip is selected. This chip has accurate voltage detection function, with a start-up threshold set to 3.08V and a shutdown threshold set to 2.8V.

[0170] The chip has an extremely low standby current of only 150nA, which can effectively reduce the power consumption of the system in standby mode.

[0171] (2) Voltage divider circuit

[0172] Voltage detection is achieved using a resistor divider network. The divider resistors R1 and R2 are selected as 51Ω and 11kΩ respectively, with a voltage division ratio of 0.5.

[0173] This voltage divider design can convert the 3.3V detection voltage into a voltage range suitable for the monitoring chip input.

[0174] (3) Switch control

[0175] An AO3400A MOSFET is used as a switch to control the on / off state of the load. This switch has an extremely short response time of only 50ms, enabling rapid circuit turn-on and turn-off operations.

[0176] 4. Load adaptation module

[0177] (1) Sampling circuit

[0178] A 20kΩ resistor divider network is used to sample the output voltage, with a division ratio of 0.5. This precise sampling circuit provides accurate voltage feedback for PID control.

[0179] (2) Microcontroller

[0180] The STM32L051 microcontroller was selected because it has low power consumption and is suitable for use in energy-constrained systems.

[0181] The microcontroller runs an incremental PID control algorithm with the algorithm parameters Kp set to 0.8, Ki set to 0.1, and Kd set to 0.05.

[0182] (3) Sensor adaptation

[0183] The system is compatible with the FRTFWS500 five-element meteorological sensor, which operates at a voltage range of 930V.

[0184] The 3.3V output voltage of the system is converted to a voltage range suitable for the sensor's operation by a DC-DC converter circuit.

[0185] The communication interface uses an RS485 bus and employs a TVS diode SMBJ6.5A for electrostatic discharge protection to ensure stable and reliable communication.

[0186] 5. Instructions for use

[0187] The method for using a sensor-based micro-energy storage system that draws power from power frequency induction includes the following steps:

[0188] (1) Energy harvesting: Select the working mode of the energy harvesting module according to the electromagnetic field environment. In an open strong magnetic field environment, the induction coil is activated to obtain energy by cutting magnetic field lines through 40-60 turns of coil; in a closed weak magnetic field environment, the energy harvesting winding is activated to couple magnetic field energy using 40-90 turns of secondary coil wound on the inductor core. The energy in both modes is output in the form of alternating current.

[0189] (2) Energy conversion: The AC power is processed by the energy conversion module, wherein the rectifier circuit performs half-wave rectification through Schottky diodes to convert the AC power into pulsating DC power, and then the ripple is smoothed by a 5-15nF filter capacitor before being stored in the energy storage module; when the voltage of the energy storage module is lower than 3.2V, the Boost converter operates at a switching frequency of 20-30kHz to boost the voltage to 3.2-3.4V;

[0190] (3) Energy storage and startup: The energy storage module stores energy through multiple surface-mount capacitors connected in parallel. When the voltage reaches the startup threshold of 3.0-3.2V, the voltage monitoring chip of the self-starting control module triggers the switching transistor to turn on, supplying power to the load adapter module and the sensor.

[0191] (4) Intermittent operation: The system enters an intermittent cycle of 2.0-2.2 seconds, of which 1.9-2.1 seconds is the energy storage stage, during which the energy storage module continuously accumulates energy; 0.1-0.2 seconds is the working stage, during which the load adapter module stabilizes the output voltage through the PID algorithm, and the sensor completes data acquisition and transmission. The peak current during the working stage is ≤19mA.

[0192] (5) Hibernation and restart: When the voltage of the energy storage module drops to the shutdown threshold of 2.7-2.9V, the self-starting control module cuts off the power supply, and the system returns to the energy storage stage, repeating steps (3)-(4) in a loop;

[0193] (6) Abnormal protection: When the input voltage is ≥380V, the clamping circuit composed of the Zener diode and the 10Ω current limiting resistor of the abnormal protection module will clamp the output voltage to 3.5V, and at the same time the sensor shortens the warning signal sending interval to 1 second.

[0194] II. Prototype Design and Experimental Results

[0195] 1. Overview of Prototype and Test Bench

[0196] Based on the principle of power frequency induction and sensor integration scheme, the prototype of the wireless temperature sensor micro energy harvesting and management system developed by this invention consists of an energy harvesting device and an energy management circuit of a micro meteorological sensor. Its circuit board size is 3.8cm×2.1cm×4.4mm, and the black chip on the back is the core component. The modular design improves the integration and space adaptability.

[0197] To adapt to different electromagnetic field environments, an air-core coil was designed. Figure 1 ) and power extraction winding ( Figure 2Two energy harvesting devices, taking transformers and inductors as examples, feature a square circuit board fixed to the exposed magnetic core surface using a 3D-printed white insulating frame. The frame serves as both insulation and a coil skeleton, while a bottom window ensures the sensor is in close contact with the device under test for accurate temperature measurement. The prototype employs a non-invasive installation method, secured by magnetic attraction or insulating adhesive, suitable for monitoring various power components. A hollow coil prototype uses 50 turns and 80mm... 2 The design outputs 138.74mW of power in a 0.05T magnetic field. The small winding type utilizes inductor core coupling and adjusts the number of secondary turns using a formula to increase the energy storage voltage in the weak field.

[0198] In hardware integration, energy management circuits ( Figure 3 The device is connected to the collection unit via flexible wires. A multi-layer PCB layout with partitioned rectifier and energy storage modules reduces losses and interference. Actual measurements at 30℃ show the energy storage capacitor retains 92% of its capacity, with an average power consumption of 5.38mW, meeting 15-day battery life requirements. Experimental verification shows that the 50-turn hollow coil prototype completes a charge / discharge cycle of 0.65V to 3.3V every 2.14 seconds at 300V and 100kHz, with a single operation time of 164ms and a transmission distance of 120 meters. The small-winding power-supply type maintains a stable energy storage voltage of 3.8V through an 80-turn secondary coil at 380V. A software timer with a 5-second interval period triggers an overvoltage warning, verifying the effectiveness of the protection logic.

[0199] The prototype achieves full-process optimization of power frequency micro-energy through compact integration, multi-source energy harvesting, and intelligent control. It innovatively integrates sensors and energy management circuits, and utilizes a 3D-printed frame and flexible PCB to improve deployment flexibility. It can reliably operate in the range of -55℃ to 125℃ and 0.03T to 0.1T, providing a low-cost solution for power equipment monitoring. In the future, it can be explored to integrate radio frequency energy capture to enhance environmental adaptability.

[0200] To apply the prototype to actual power electronic devices, this invention selects a synchronous Buck converter as the test bench, such as... Figure 4 As shown in the table, the operating conditions of this synchronous Buck converter are as follows.

[0201] Table 1 Operating conditions of synchronous Buck converter

[0202] parameter symbol Value Input voltage <![CDATA[-V S ]]> 300V Input power <![CDATA[P S ]]> 1500W load resistor R 20Ω Switching frequency <![CDATA[f s ]]> 100kHz Duty cycle D 0.6

[0203] 2. Analysis of Experimental Results

[0204] (1) The influence of coil turns on energy extraction capability and threshold verification

[0205] To investigate the impact of key parameters of the energy harvesting device on the system's startup capability, coil turns gradient tests were conducted on a synchronous Buck converter test bench (input voltage 300V, switching frequency 100kHz, duty cycle 0.6). Experimental data showed that when the air-core coil had 30 turns, the energy storage module voltage could only rise to 1.8V and remain stable, failing to reach the self-starting module's threshold of 3.08V. When the number of turns increased to 40, the energy storage voltage rose to 2.5V but still did not trigger startup. This is because the diode conduction loss of the rectifier module (0.37V × load current), the ESR loss of the energy storage capacitor, and the monitoring loss of the self-starting module (150nA × Vin) increase with voltage, leading to a dynamic balance between energy harvesting and losses. When the number of turns was increased by 50, the energy storage voltage successfully exceeded the 3.08V threshold, and the system entered intermittent operation mode. This verified the positive correlation between the number of coil turns and the energy harvesting capacity, i.e., increasing the number of turns can increase the induced electromotive force (E=N×dΦ / dt), but the influence of the coil internal resistance (R=ρ×N×2πr / S) on the losses must be considered. With 50 turns, the internal resistance is approximately 0.8Ω, achieving a power output of 138.74mW under a 0.05T magnetic field, meeting the energy consumption requirement of 7.61mJ for a single operation. The coil turns and energy harvesting situation are shown in the table below:

[0206] Table 2. Number of coil turns and energy extraction.

[0207] Number of coil turns Can the energy harvesting reach the threshold value of the self-starting module? Specific details 30 turns no The energy storage module voltage rose to 1.8V and then remained constant. 40 turns no The energy storage module voltage remained constant after rising to 2.5V. 50 turns yes Able to complete intermittent work normally

[0208] (2) Energy flow characteristics of intermittent working mode

[0209] In a weak electromagnetic field environment (corresponding to Case 1), using a 50-turn hollow coil as the energy source, the system exhibits a typical periodic intermittent "energy storage operation" mode. For example... Figure 5 As shown in (a), a single working cycle is 2.14 seconds, divided into an energy storage phase (interval A, approximately 2 seconds) and a working phase (interval B, approximately 0.14 seconds). During the energy storage phase, the self-starting module disconnects the load circuit, and the energy storage capacitor (2200μF) is charged through the half-wave rectifier circuit at an average current of 9.5mA. The voltage rises linearly from 0.65V to 3.3V, with a charging power of approximately 15mW (considering rectification losses). When the voltage reaches the 3.08V threshold, the switching transistor AO3400A is turned on, and the load (micro weather sensor + boost module) discharges at an average current of 19.5mA. The energy storage voltage drops rapidly to 0.65V within 0.14 seconds, releasing approximately 11.51mJ of energy, which meets the energy consumption requirements of sensor temperature measurement and RF transmission.

[0210] Amplified waveform of interval B ( Figure 5(b) As can be seen, the VDD waveform exhibits three sharp fluctuations, corresponding to the three power consumption stages of the sensor's "temperature measurement, analog-to-digital conversion, and wireless transmission": during the temperature measurement stage, the current is approximately 8mA, and the voltage stabilizes at 3.3V; during the RF transmission stage, the peak current is 19mA, causing VDD to momentarily drop to 3.0V, which is subsequently restored to stability through PID regulation of the boost module. This phenomenon indicates that sudden load changes can cause short-term voltage fluctuations, requiring optimization of the PI controller parameters (such as increasing the proportional coefficient Kp) to improve the dynamic response speed. In the experiment, the adjustment time was controlled within 50ms using an incremental PID algorithm, and the output ripple was suppressed within ±0.1V.

[0211] (3) System adaptability under strong electromagnetic field environment

[0212] When switching to the small power-harvesting winding as the energy harvesting device (corresponding to case two), the system exhibits stronger environmental adaptability as the inductor input voltage gradually increases to 380V. For example... Figure 6 As shown, the energy storage voltage stabilizes at 3.8V under a strong magnetic field. By forcibly setting a 5-second interval period through a software timer, the sensor sends temperature data every 5 seconds. At this time, the energy harvesting power (about 50mW) and the load power consumption (average 5.38mW) form a positive margin, and the voltage fluctuation of the energy storage capacitor is less than 0.2V, which verifies the stable control capability of the self-starting module when the energy is sufficient.

[0213] Further increasing the input voltage to 380V corresponds to an increase in electromagnetic field strength to 0.1T, and the energy storage voltage exceeds 4.8V, approaching the microcontroller's maximum operating voltage safety threshold of 3.6V. At this point, the system triggers an overvoltage protection mechanism: on one hand, the Zener diode ZD1 (3V) enters a breakdown state, clamping VDD at 3.5V; on the other hand, the microcontroller continuously sends temperature data (with the interval shortened from 5 seconds to 1 second) as a warning signal, such as... Figure 7 As shown in the figure. This experiment verifies the effectiveness of the hardware protection logic and software alarm strategy, and also shows that it is necessary to increase the number of turns in the small power winding (e.g., from 50 turns to 80 turns) or optimize the voltage withstand of the energy storage capacitor (replacing it with a model of 6.3V or higher) to expand the safe operating range of the system in strong magnetic field scenarios.

[0214] (4) Power consumption characteristics and energy efficiency assessment

[0215] Through formula

[0216]

[0217] The calculated energy accumulated in a single energy storage cycle is:

[0218] w = 0.5 × 2200 × 10 6 ×(3.33 2 0.652 = 11.73mJ

[0219] Average power consumption is:

[0220] p=w / T=11.51mJ / 2.14s≈5.38mW

[0221] This power consumption level is significantly lower than traditional battery-powered solutions (such as the CR2032 with a 225mAh battery capacity, providing approximately 12 days of battery life at an average power consumption of 5mW), and it eliminates the need for battery replacement, demonstrating the maintenance-free advantage of line-frequency power supply. Comparing the CCM and DCM boost modes, although the DCM mode reduces the inductor size by 2mm... 3 This results in a 21ms reduction in power supply time (from 185ms to 164ms), but an overall energy efficiency improvement of 3.2% (measured efficiency 85% vs. 82% in CCM mode), thanks to the low ESR inductance (470μH vs. 1mH) and dynamic duty cycle adjustment strategy.

[0222] (5) Monitoring accuracy and data transmission reliability

[0223] The sensor's temperature measurement error is less than ±0.5℃ within the 30℃-80℃ temperature range, meeting the requirements for thermal monitoring of power equipment. The 16-bit message parsed by the receiver via a serial port assistant includes the chip ID (first 10 bits), temperature data (4 bits, resolution 0.1℃), and CRC checksum (2 bits), with a bit error rate of less than 0.1% over a transmission distance of 120 meters. In the experiment, when the energy storage voltage dropped to 2.8V, the boost module could still maintain VDD = 3.0V ± 0.2V, ensuring uninterrupted data transmission and verifying the role of the self-starting module's hysteresis characteristic (0.28V) in ensuring communication reliability.

[0224] (6) Robustness testing under extreme conditions

[0225] In a -55℃ low-temperature environment, the surface-mount capacitor (GRM31CR60J227ME11L) maintained 92% capacitance, and the ESR value increased from 0.1Ω to 0.15Ω, resulting in an extended energy storage cycle of 2.3 seconds, but the system could still start normally. At a high temperature of 125℃, the capacitor leakage current increased from 1μA to 5μA, and the energy storage efficiency decreased to 78%. After extending the interval to 3 seconds via software, the system returned to stable operation. In addition, in electromagnetic interference testing, by adding a magnetic shielding layer to the circuit board, RF noise was suppressed to within ±50mV, ensuring the sampling accuracy of the PI controller.

[0226] The prototype utilizes a 3D-printed insulating frame (38×21×4.4mm) for non-intrusive installation, and its magnetic structure accommodates curved components such as transformers and inductors, with installation taking less than 5 minutes. Compared to traditional wired temperature measurement solutions, this prototype requires no modification to the existing circuitry and supports multi-node distributed deployment. In 10kV switchgear temperature measurement scenarios, a single node can cover a radius of up to 2 meters, reducing wiring costs by 80%. Future integration of flexible PCB technology can further reduce the size to 20×15×3mm, adapting to even smaller monitoring spaces.

[0227] This invention focuses on a micro energy storage module that uses power frequency induction to obtain electricity. It elaborates on the prototype design architecture, experimental scheme and result analysis, as well as the feasibility and reliability of the invention system in terms of energy harvesting, management and load driving, providing key technical support for distributed monitoring of smart grids.

[0228] The above description, in conjunction with preferred embodiments, provides a further detailed explanation of the present invention and should not be construed as limiting the specific implementation of the invention to these descriptions. For those skilled in the art, various substitutions or modifications can be made to these described embodiments without departing from the inventive concept, and all such substitutions or modifications should be considered within the scope of protection of the present invention.

[0229] Although the invention and its advantages have been described in detail, it should be understood that various changes, substitutions, and modifications can be made without departing from the spirit and scope of the invention. Furthermore, the scope of the invention is not limited to the specific embodiments of the processes, manufactures, compositions of matter, methods, and steps described in the specification. From the disclosure of this invention, those skilled in the art will readily utilize existing or future processes, manufactures, compositions of matter, methods, or steps that substantially perform the same function or achieve the same results as the corresponding embodiments described herein. Therefore, the appended claims are intended to encompass such processes, manufactures, compositions of matter, methods, or steps.

Claims

1. A sensor-based micro-energy storage system based on power frequency induction, characterized in that, include: Energy harvesting module, energy conversion module, energy storage module, self-starting control module, load adaptation module, and fault protection module; The output terminal of the energy harvesting module is electrically connected to the input terminal of the energy conversion module, transmitting the harvested AC power to the energy conversion module; The output terminal of the energy conversion module is electrically connected to the input terminal of the energy storage module and the detection terminal of the self-starting control module, respectively. The rectified output of the energy conversion module is connected to the energy storage module for energy storage and provides a voltage monitoring signal to the self-starting control module. The output terminal of the energy storage module is electrically connected to the input terminal of the self-starting control module, providing working power to the self-starting control module; The control terminal of the self-starting control module is electrically connected to the enable terminal of the load adapter module, and the power supply of the load adapter module is controlled by switching the switch on and off. The input terminal of the load adapter module is electrically connected to the boost output terminal of the energy conversion module, and supplies power to the external sensor after receiving a stable voltage. The abnormal protection module is connected in parallel between the output terminal of the energy conversion module and ground to provide clamp protection against system overvoltage.

2. The sensor micro-energy storage system based on power frequency induction power extraction according to claim 1, characterized in that, The energy harvesting module includes an induction coil and an energy harvesting winding. The induction coil has 40-60 turns and a cross-sectional area of ​​70-90 mm². 2 The output power is ≥130mW under a magnetic field of 0.04-0.06T; the energy harvesting winding is wound on the inductor core, and the number of secondary turns is 40-90.

3. The sensor micro-energy storage system based on power frequency induction power extraction according to claim 1, characterized in that, The induction coil and the energy harvesting winding are connected to the energy conversion module via a flexible PCB, which has a temperature range of -55℃ to 125℃.

4. The sensor micro-energy storage system based on power frequency induction power extraction according to claim 1, characterized in that, The energy conversion module includes a rectifier circuit, a filter circuit, and a boost circuit. The input terminal of the rectifier circuit is electrically connected to the output terminal of the energy harvesting module, and the output terminal is electrically connected to the input terminal of the filter circuit. The output terminal of the filter circuit is electrically connected to the input terminals of the energy storage module and the boost circuit, respectively. The output terminal of the boost circuit is electrically connected to the input terminal of the load matching module, and the control terminal of the boost circuit is electrically connected to the signal output terminal of the self-starting control module. The rectifier circuit uses a Schottky diode with a forward voltage drop ≤0.4V. The filter circuit uses a 5-15nF capacitor. The boost circuit is a Boost converter operating in DCM mode, including a 400-500μH inductor and a switching transistor with a forward resistance ≤30mΩ, and a switching frequency of 20-30kHz.

5. The sensor micro-energy storage system based on power frequency induction power extraction according to claim 1, characterized in that, The energy storage module uses multiple surface-mount capacitors connected in parallel to form an 1800-2400μF energy storage unit. The equivalent series resistance of the surface-mount capacitors is ≤0.15Ω, and the operating temperature range is -55℃ to 125℃. The input terminal of the energy storage module is electrically connected to the output terminal of the filter circuit in the energy conversion module, and the output terminal is electrically connected to the voltage sampling terminal of the self-starting control module.

6. The sensor micro-energy storage system based on power frequency induction power extraction according to claim 1, characterized in that, The self-starting control module includes a voltage monitoring chip, a resistor divider network, a switching transistor, and an intermittent operating mode. The input terminal of the resistor divider network is electrically connected to the output terminal of the energy storage module, and the output terminal is electrically connected to the sampling terminal of the voltage monitoring chip. The output terminal of the voltage monitoring chip is electrically connected to the control electrode of the switching transistor, the input terminal of the switching transistor is electrically connected to the boost output terminal of the energy conversion module, and the output terminal is electrically connected to the power supply terminal of the load adapter module. The voltage monitoring chip has a start-up threshold of 3.0-3.2V and a turn-off threshold of 2.7-2.9V. The standby power consumption of the self-starting control module is ≤200nA. The voltage division ratio of the resistor divider network is 0.4-0.

6. The on-resistance of the switching transistor is ≤30mΩ, and the response time is ≤60ms. The power supply cycle of the intermittent operating mode of the self-starting control module is 2.0-2.2 seconds, including a 1.9-2.1 second energy storage stage and a 0.1-0.2 second operating stage, with a peak current of ≤19mA during the operating stage.

7. The sensor micro-energy storage system based on power frequency induction power extraction according to claim 1, characterized in that, The load adaptation module adopts a PID algorithm and has an output voltage of 3.2-3.4V. The load adaptation module includes a sampling feedback circuit. The input terminal of the sampling feedback circuit is electrically connected to the output terminal of the load adaptation module, and the output terminal is electrically connected to the input terminal of the PID controller. The sampling feedback circuit adopts a 15-25kΩ resistor voltage divider network. The average power consumption of the system is ≤6mW.

8. The sensor micro-energy storage system based on power frequency induction power extraction according to claim 1, characterized in that, The load adapter module includes an interface conversion circuit. The input terminal of the interface conversion circuit is electrically connected to the output terminal of the load adapter module. An external sensor is connected to the output terminal. The integrated communication interface uses a TVS diode for electrostatic discharge protection. The TVS diode is connected in parallel between the signal terminal of the communication interface and ground.

9. The sensor micro-energy storage system based on power frequency induction power extraction according to claim 1, characterized in that, The abnormal protection module includes a clamping circuit consisting of a Zener diode and a 10Ω current-limiting resistor connected in series. The input terminal of the clamping circuit is electrically connected to the boost output terminal of the energy conversion module, and the output terminal is grounded.

10. The method of using the sensor micro-energy storage system based on power frequency induction as described in claim 1, characterized in that, Includes the following steps: (1) Energy harvesting: Select the working mode of the energy harvesting module according to the electromagnetic field environment. In an open strong magnetic field environment, the induction coil is activated to obtain energy by cutting magnetic field lines through 40-60 turns of coil; in a closed weak magnetic field environment, the energy harvesting winding is activated to couple magnetic field energy using 40-90 turns of secondary coil wound on the inductor core. The energy in both modes is output in the form of alternating current. (2) Energy conversion: The AC power is processed by the energy conversion module, wherein the rectifier circuit performs half-wave rectification through Schottky diodes to convert the AC power into pulsating DC power, and then the ripple is smoothed by a 5-15nF filter capacitor before being stored in the energy storage module; when the voltage of the energy storage module is lower than 3.2V, the Boost converter operates at a switching frequency of 20-30kHz to boost the voltage to 3.2-3.4V; (3) Energy storage and startup: The energy storage module stores energy through multiple surface-mount capacitors connected in parallel. When the voltage reaches the startup threshold of 3.0-3.2V, the voltage monitoring chip of the self-starting control module triggers the switching transistor to turn on, supplying power to the load adapter module and the sensor. (4) Intermittent operation: The system enters an intermittent cycle of 2.0-2.2 seconds, of which 1.9-2.1 seconds is the energy storage stage, during which the energy storage module continuously accumulates energy; 0.1-0.2 seconds is the working stage, during which the load adapter module stabilizes the output voltage through the PID algorithm, and the sensor completes data acquisition and transmission. The peak current during the working stage is ≤19mA. (5) Hibernation and restart: When the voltage of the energy storage module drops to the shutdown threshold of 2.7-2.9V, the self-starting control module cuts off the power supply, and the system returns to the energy storage stage, repeating steps (3)-(4) in a loop; (6) Abnormal protection: When the input voltage is ≥380V, the clamping circuit composed of the Zener diode and the 10Ω current limiting resistor of the abnormal protection module will clamp the output voltage to 3.5V, and at the same time the sensor shortens the warning signal sending interval to 1 second.

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