506 results about "Current pulse" patented technology

The invention discloses a wiring harness dynamic load and electromagnetic interference coupling test method, and relates to the technical field of wiring harness testing, and the method comprises the steps: S1, defining a plurality of environment parameter groups, and constructing a test platform; s2, dynamic current pulse and multi-axis vibration excitation are synchronously loaded; s3, applying broadband electromagnetic interference signals and monitoring signal crosstalk amplitude and bit error rate changes; s4, the sensor nodes are dynamically configured according to the topological structure of the wire harness; s5, generating a feature vector; s6, outputting a wire harness performance index; s7, outputting a wire harness fault probability prediction value; s8, obtaining prediction data; s9, triggering a high-speed data recording mode, and storing original sensor data 60 seconds before the fault; and dynamically adjusting the gradient step length and the loading sequence in the environment parameter group. Performance evaluation, fault prediction and service life management can be carried out on the wire harness under complex working conditions, and the reliability and safety of an automobile electrical system are improved.

The invention discloses a high-voltage cable operation state on-line monitoring, intelligent early warning and fault positioning system, particularly relates to the technical field of power equipment insulation monitoring, and is used for solving the problems that transient discharge signals generated in the cable insulation degradation process are difficult to effectively capture and accurate fault positioning cannot be realized in the prior art. The method comprises the following steps: collecting transient leakage current signals and traveling wave propagation characteristic parameters, performing phase correlation analysis on leakage current pulses and power frequency voltage to identify discharge types, and performing variational mode decomposition and Hilbert-Huang transform on the signals to respectively extract complexity characteristics and energy distribution characteristics; signal logic conflicts are judged by analyzing similarity and statistical distance among characteristics of a plurality of monitoring points, and collaborative diagnosis is started or traveling wave distance measurement is directly utilized to carry out insulation state evaluation and fault location. And finally, differential early warning levels are generated according to the diagnosis result, and fault line selection and positioning information is output to realize real-time monitoring, intelligent early warning and accurate positioning of the operation state of the high-voltage cable.

A power converting apparatus includes a rectifier unit that rectifies first alternating-current power supplied from a commercial power supply, a capacitor connected to an output end of the rectifier unit, an inverter connected across the capacitor to generate second alternating-current power and output the second alternating-current power to a motor, and a control unit that controls an operation of the inverter and an operation of the motor using a dq-rotational coordinate system rotating in synchronization with a rotor position of the motor. The control unit extracts multiple frequency components from a q-axis current pulsation, which is a pulsatile component of a q-axis current, and limits the amplitude value of each of the extracted frequency components to control the amplitude of the q-axis current pulsation.

The invention discloses an oil-immersed transformer active defense method and system based on pulse current characteristics. The acquisition device is used for acquiring output signals of high-frequency pulse current sensors mounted at a high-voltage bushing end screen grounding position, a high-voltage bushing position and an iron core grounding position to obtain digital pulse current signals; whether active defense is started or not is judged according to whether the instantaneous value of the pulse current signal at the iron core grounding position reaches a protection starting threshold or not; judging whether the current pulse cluster is a discharge pulse cluster with abnormal internal discharge or not based on the three groups of pulse current signal characteristics; and judging whether protection acts or not according to the number of abnormal discharge pulse clusters in a set period. According to the method, serious partial discharge in the large oil-immersed transformer can be identified, protection measures are actively taken, and the situation that serious discharge defects are further developed into arc breakdown faults is effectively avoided.

A level shifter includes: a low voltage domain configured to output non-overlapping first and second current pulses based on opposite edges of a logic input signal; and a high voltage domain comprising a latch and a current mirror circuit configured to mirror the non-overlapping first and second current pulses such that the latch is set when the first current pulse is active and reset when the second current pulse is active. The current mirror circuit includes a first mirroring path for the first current pulse and a second mirroring path for the second current pulse. The level shifter has a common mode slew current that is added to the non-overlapping first and second current pulses. The first mirroring path and the second mirroring path are cross-coupled such that the common mode slew current is reduced or cancelled before the non-overlapping first and second current pulses are input to the latch.

The present disclosure concerns a method for measuring a degradation of thermal characteristics of a power module comprising sequences of: - injecting current pulses (Pinj), having a voltage-clamped constant amplitude (IInj), between an emitter and a gate of a power semiconductor of such power module, a duration of said voltage-clamped constant amplitude (Iinj) current pulses (Pinj) being modulated periodically with a modulation frequency (Fmod), said current pulses causing losses modulated with said modulation frequency (Fmod), - measuring a parameter (k.Tj) dependent of a junction temperature (Tj) of such power semiconductor at the beginning of said current pulses, - measuring a phase shift (Δφ) between said modulation frequency (Fmod) and said parameter (k.Tj), said phase shift (Δφ) providing a health indicator for the power module.　

The invention discloses a direct current B code wave recording alarm analysis device and method based on an FPGA, and relates to the technical field of power system automation and signal analysis, and the device comprises an FPGA collection module which is used for collecting a TTL level signal of a direct current B code in real time at a preset sampling frequency, recording a high-precision timestamp of each sampling point, and carrying out the subsequent pulse parameter calculation; the pulse width measurement module is connected with the FPGA acquisition module, is used for calculating the pulse width of the current pulse based on the rising edge timestamp and the falling edge timestamp of the signal, triggering a wave recording module, and is used for starting wave recording operation when the pulse width is detected to exceed a preset threshold range or abnormity occurs for a plurality of times continuously; collecting complete waveform data before and after the fault; the DC B code wave recording alarm analysis device and method based on the FPGA improve the intelligent level, response speed and fault visualization capability of a B code monitoring system, and are especially suitable for high-reliability monitoring and management scenes of key synchronization signals in a DC system.

The present application relates to a device and method for surveying a power line-buried path, wherein the device includes a transmitter which selects a balanced / unbalanced voltage to output input and rectified output power as a current pulse in the form of an unmodulated pulse or a frequency-modulated signal when a current pulse signal is transmitted to a conductor (power line) of a public distribution network, and a receiver in which a plurality of magnetic field sensors inductively couple the pulse or the frequency-modulated signal within a near magnetic field distance to obtain a difference value in each direction to obtain a depth.

The invention provides a leakage current testing method and system based on a low-frequency EIS and a transverse current pulse, and relates to the technical field of leakage current testing. The method comprises the following steps: firstly, determining use information and low-frequency EIS test parameters of a target battery to be tested, then testing the battery by using electrochemical working equipment according to the parameters, obtaining impedance data under different frequencies, and further obtaining first dynamic capacitance information. And controlling the power supply equipment to apply a preset transverse pulse current to the battery, determining a voltage variation cut-off condition, continuously monitoring the voltage variation, and recording the test time variation when the cut-off condition is reached. And finally, the leakage current value of the battery is determined by integrating the first dynamic capacitance information, the transverse current pulse current, the test time variation and the voltage variation. Compared with a traditional method, the leakage current value can be obtained only by applying the direct current once after the low-frequency EIS test without changing the magnitude and the duration time of the current for many times, the test process is simplified, the test efficiency is improved, and the leakage current value can be determined more accurately.

The invention relates to the technical field of beam measurement, and provides a beam integration device, which comprises a logic control module and a plurality of integration modules, each integration module is used for being correspondingly connected with one output channel of a dose distribution detector, and each integration module comprises a current gear selection circuit, an integration circuit and a polarity discrimination circuit, the current gear selection circuit comprises a plurality of current gear channels; the current gear selection circuit is used for selecting a target current gear channel to be connected with an output channel corresponding to the dose distribution detector under the control of the logic control module, and converting a current pulse signal output by the output channel corresponding to the dose distribution detector into a voltage signal; the polarity discrimination circuit discriminates the polarity of the voltage signal and converts the voltage signal into the polarity required by the integrating circuit. According to the beam current integration device, simultaneous integration of multi-channel bipolar current pulse signals is realized, and the integration range is automatically switched according to the change of the current pulse signals.

The invention relates to the technical field of capacitor charging and discharging control, in particular to a super-capacitor charging and discharging control method and system, and the method comprises the steps: transmitting a preset low-current pulse test signal to a super-capacitor, and recognizing the characteristics of the capacitor; according to the capacitance characteristics, selecting a target charging path from the preset charging paths for staged charging; a charging stage verification model is set for charging stage verification, and whether a charging stage switching condition is met or not is judged by combining real-time monitoring of the internal resistance change rate and the voltage climb rate; a parallel state monitor is designed, and the optimal control parameters of the next charging stage are calculated in parallel based on the target charging path while the control of the current charging stage is executed; when the charging stage switching condition is met, the optimal control parameters are loaded immediately for charging stage switching; monitoring the state of the capacitor in the charging process in real time, and returning to the previous stable charging stage and re-identifying the characteristics of the capacitor when an abnormal state is detected; and when the retry times exceed a preset upper limit, switching to a safety protection mode.

The invention discloses an energy-saving control method for a new-energy high-low-voltage direct-current relay. The energy-saving control method comprises the steps of analyzing a mapping relation between a silicon steel sheet stacking angle and a magnetic flux path deviation, calculating magnetic domain wall moving resistance according to magnetic domain boundary stress, determining a magnetic domain overturning speed by combining a magnetic field change rate, and measuring a hysteresis loop width parameter. Adjusting the width and frequency of the excitation current pulse according to the magnetic domain overturning frequency and the hysteresis loop offset and width to obtain an optimized excitation current pulse sequence, and determining the hysteresis loop expansion speed according to the hysteresis loop area change rate; the local high-temperature area temperature is analyzed through the iron core temperature rise rate, the local high-temperature area distribution and the magnetic domain energy dissipation data, if the local high-temperature area temperature exceeds the preset threshold value, the excitation current pulse is adjusted, stable iron core temperature rise control data is obtained, the coercive force change amplitude is determined, the magnetic hysteresis loss and the temperature rise are reduced, the stability of the relay under high-frequency switching is improved, and the reliability of the relay is improved. And the operation efficiency and reliability of the system are greatly improved.

The invention provides a diesel-storage hybrid power anti-overload system and device based on a network-forming inverter, and a medium. A pre-synchronization module realizes seamless switching between a VSG mode and a PQ mode based on dynamic voltage amplitude matching, phase-locked loop frequency synchronization and phase real-time alignment technologies; the hardware current limiting module adopts high-speed current monitoring and hardware-level protection logic to cut off an overcurrent pulse in real time and prevent a power device from failing due to transient impact; the power suppression module optimizes the power distribution of the diesel generator and the energy storage by judging an overload threshold value and a steady state recovery condition in real time; the logic judgment module coordinates the diesel generator dynamic frequency modulation and energy storage mode switching, the diesel generator preferentially bears the transient power difference when the load suddenly changes, and the energy storage mode is seamlessly switched to the network construction mode after the system recovers the steady state; according to the system, through software and hardware full-link collaborative design, the problems of transient overload and mode switching instability of the diesel storage system are solved, and the stability and energy efficiency of the diesel storage hybrid power system are improved.

The invention provides an aviation transient electromagnetic constant-amplitude in-phase parallel transmitter system, and the system comprises a power management unit which is used for supplying power; the full-bridge inverter circuit unit comprises a plurality of MOSFET full-bridge inverter modules which are arranged in parallel, each MOSFET full-bridge inverter module sends out a constant-amplitude in-phase bipolar parallel current pulse to a transmitting load connected with the MOSFET full-bridge inverter module, so that each transmitting load generates a constant-amplitude in-phase electromagnetic field, and the constant-amplitude in-phase electromagnetic fields are superposed and jointly act on a to-be-detected target; the active self-adaptive voltage-adjustable double-clamping unit is connected with the full-bridge inverter circuit unit and is used for clamping the rising edge and the falling edge of each sub-pulse in the equal-amplitude in-phase bipolar parallel current pulse; the control unit is used for generating a PWM (Pulse Width Modulation) sequential logic control signal to control the full-bridge inverter circuit unit, so that each MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor) full-bridge inverter module outputs a constant-amplitude in-phase bipolar parallel current pulse; and the detection unit is used for detecting the emission current, the clamping current and the clamping voltage respectively and feeding back detection results to the control unit.

The invention discloses a current pulse generator noise reduction method and device, and relates to the technical field of current pulse generator noise reduction, and the method specifically comprises the following steps: removing a main pulse waveform from a filter response sequence, extracting filter residual response segments of a plurality of periods, carrying out the time alignment and overlapping processing of the residual response segments of the plurality of periods, and carrying out the noise reduction of the current pulse generator. Constructing a residual energy superposition trend line; based on the residual energy superposition trend line, a Savitzky-Golay sliding window polynomial fitting derivative algorithm is adopted to calculate a trend offset rate parameter, and a wavelet packet decomposition and Shannon entropy calculation algorithm is adopted to generate a disturbance frequency domain diffusivity parameter so as to reflect whether the residual energy superposition behavior of the filter is evolved into self-excitation background noise. According to the method, the problem that residual energy superposition of the filter is difficult to recognize under continuous narrow pulses is solved, precise recognition and dynamic intervention control of self-excitation background noise are realized, and the system stability is improved.

The invention relates to an electrochemical impedance spectroscopy on-line measurement method and device, electronic equipment and a storage medium, and the electrochemical impedance spectroscopy on-line measurement method can collect time domain signals of a lithium battery under the excitation of a large-current pulse, such as voltage signals and current signals of the lithium battery in a large-current pulse charging state. During large-current pulse charging, a to-be-measured curve based on a time domain signal is converted into frequency domain information with the deviation of an electrochemical station reference curve smaller than a preset deviation through wavelet transform, impedance information is determined according to parameter information of a wavelet basis function in the conversion process, and an electrochemical impedance spectrum of the lithium battery is determined according to all the impedance information. Due to the fact that time-frequency analysis of the lithium battery under large-current pulse excitation can be completed, large-current pulse charging is achieved, and meanwhile online electrochemical impedance spectroscopy measurement is conducted on the lithium battery.

The invention discloses an array type electromagnetic detection emission synthesis excitation system and method, and the system comprises an emission coil module which is formed by arranging a plurality of emission coils at certain intervals into a square, a circle or other structures; the emission control module is used for dynamically adjusting parameters of emission current according to detection requirements and environmental conditions and controlling the working state of the emission coil module; the time reference synchronization module is used for receiving time and position signals provided by a satellite, calibrating a clock and a position through a satellite positioning signal, and realizing synchronous emission of a plurality of coils; the time reference synchronization module sends satellite time and position signals to the emission control module; the emission control module generates an emission instruction according to a time reference and sends the emission instruction to each emission coil module; and each transmitting coil module simultaneously transmits a current pulse according to the received transmitting instruction to generate a stable electromagnetic field. Flexible arrangement modes such as unmanned aerial vehicle carrying or single-person carrying can be achieved.

The invention discloses a manufacturing process of a COB (Chip On Board) process circuit board for photoelectric display. The manufacturing process comprises the following steps: performing constant-amplitude direct-current driving on a light-emitting chip array before injection of packaging glue to obtain full-board light field baseline data; the refractive index distribution of the packaging adhesive is regulated and controlled through multi-phase current pulses after the packaging adhesive is injected; forming a composite structure of a high-refractive-index chip interconnection interface and a low-refractive-index packaging surface by using Joule heat in a packaging adhesive crosslinking stage; the metal surface roughness is adjusted through nanosecond cosine pulses so as to control the plasma resonance characteristic; and finally, carrying out fine adjustment on the local refractive index by utilizing the interaction of the moving ions and the polar side chain. According to the technical scheme, stable refractive index distribution can be formed in the chip packaging structure through multi-physics field coupling regulation and control, formation of sub-wavelength stray light waveguides is effectively restrained, the problems of dynamic color cast and brightness flicker in an ultra-small pixel pitch COB display device are solved, and the optical performance consistency of the device is improved.

The present invention discloses a gas overflow detection method and a diaphragm gas meter, belonging to the technical field of gas meters. The method comprises: using a first timer with a first timing step to measure the pulse time interval of the diaphragm gas meter; when the count value of the first timer corresponding to the current pulse time interval is less than or equal to the first counting threshold, using a second timer with a second timing step to measure the subsequent pulse time interval of the diaphragm gas meter; the second timing step is less than the first timing step; when the count values ​​of the second timer in the pulse time intervals of a preset number of consecutive times are all less than or equal to the second counting threshold, confirming that an overflow anomaly occurs; the first or second counting threshold is the count value corresponding to the pulse time interval corresponding to the overflow threshold when the first or second timing step is used for measurement; the preset number is less than the number of complete pulse time intervals that pass within the detection time limit when gas is leaking at the overflow threshold. The present invention can timely and accurately detect gas overflow anomalies.

The invention provides a voltage difference monitoring device and method for a bootstrap switching power supply and the switching power supply. The device comprises a voltage difference detection module which is configured to detect the voltage difference between the two ends of a bootstrap capacitor and generate a lower tube conduction indication signal if the voltage difference does not reach a set threshold value; the lower tube forced conduction module is configured to generate a plurality of continuous pulse signals according to the lower tube conduction indication signal so as to conduct a lower transistor when the pulse signals are in high level, so that the bootstrap capacitor is charged through the first power supply voltage until the voltage difference reaches a set threshold value; and the negative current detection module is configured to send a forced turn-off signal to the lower transistor forced turn-on module and end the turn-on period, corresponding to the current pulse signal, of the lower transistor if a negative current greater than a threshold value is detected during the period of turning on the lower transistor through the pulse signal. According to the invention, high differential pressure detection precision is realized through a simple circuit structure.

A system comprises a seed laser diode, a semiconductor optical amplifier, and a driver. The seed laser diode is configured to produce a seed optical signal. The semiconductor optical amplifier is configured to, based on an injected amplifier current pulse, amplify the seed optical signal to produce an emitted optical signal. The driver is configured to provide to the seed laser diode or the semiconductor optical amplifier, a profiled compensation current associated with the injected amplifier current pulse to at least in part control a frequency chirp of the emitted optical signal.

The invention discloses a current overload early warning detection method and system for a power adapter, and the method comprises the steps: injecting a sweep frequency signal into each port of a multi-port power adapter, and obtaining an impedance spectrum and a level signal of each port; calculating a level change rate by using sliding window filtering; according to the impedance spectrum and the level change rate, identifying a real-use port, identifying a low-power-consumption port and a no-load port through micro-current pulse detection, monitoring the current of each port in real time, predicting a future current change trend, and judging whether the current change trend has that the current exceeds an overload threshold at a certain moment; if yes, triggering graded early warning; and if not, identifying an effective port based on the load state tag, establishing a multi-port current-voltage transfer function matrix, and optimizing current distribution of the effective port in combination with an MPC model. According to the method, the port load state can be accurately identified, the overload risk is pre-judged in advance, graded early warning is triggered, and when overload is not detected, current distribution is optimized to realize dynamic balance of multi-port power.

The invention relates to the technical field of discharge monitoring, and provides a high-precision monitoring method and system for partial discharge current pulse signals. The method comprises the following steps: activating distributed broadband monitoring equipment to continuously monitor a transformer to obtain distributed monitoring information; extracting first monitoring information, and performing feature collection on the first pulse signal to obtain a pulse feature set; establishing a multi-conductor transmission line model based on the multi-dimensional characteristic parameters of the transformer, and performing simulation to obtain simulation information; and calling a partial discharge positioning strategy to analyze the pulse feature set and the simulation information, and determining the partial discharge source of the transformer. According to the invention, the technical problems that the partial discharge pulse signal in the transformer cannot be accurately extracted and analyzed and the accurate positioning of the partial discharge source is influenced because the detection blind area is easily influenced by electromagnetic interference and the weak signal identification is insufficient in the existing partial discharge monitoring method are solved; the technical effect of high-precision partial discharge source positioning is achieved.

The invention belongs to the field of battery management systems, and particularly relates to a battery model off-line identification method based on time-frequency domain combination, which comprises the following steps: acquiring an impedance spectrum through EIS test, extracting omega max, and directly calculating R1 and C1; performing a short-time direct-current pulse test, applying a short-time constant-current pulse to the battery, and collecting voltage response data; taking the frequency domain parameter as a constraint, and fitting a large time parameter by using time domain data; and model verification: integrating parameters and verifying the dynamic response precision of the full time scale. Small time constants are accurately captured through frequency domain analysis, and large time parameters are optimized through time domain fitting, so that dynamic errors of the model are reduced; frequency domain rapid decoupling reduces the time domain test duration, and the comprehensive test time is shortened; high-frequency and high-precision time domain acquisition equipment is not needed, and only a conventional EIS instrument and a pulse testing device are needed; the method is suitable for electric vehicles, energy storage systems and other scenes with high requirements for real-time performance and precision.

The invention relates to a method for determining the temperature of a transistor, a transistor driver device and a system. A method of determining a temperature of a transistor (11) is provided. The method comprises providing a current pulse having a predefined length and a predefined current magnitude to a control terminal (15) of the transistor (11) and measuring a voltage at the control terminal (15). The temperature of the transistor (11) is determined on the basis of the measured voltage.

The invention relates to the technical field of switch fault testing, in particular to a power switch fault testing device and method. The method comprises the following steps: deploying a switch multiplexing test fixture; controlling the switch multiplexing test fixture to perform contact current pulse excitation test on the power switch to be tested, and synchronously acquiring contact group pulse response data; according to the contact group pulse response data, contact abnormal jump event evaluation, contact resistance fluctuation rate analysis and contact magnetic field abnormal mode analysis are carried out, and then single-contact fault type analysis is carried out according to the contact magnetic field abnormal mode, the contact resistance fluctuation rate and the jump abnormal event evaluation data of each contact. And obtaining power switch fault data. According to the invention, independent current pulse excitation testing is carried out on each contact of the power switch, so that single-contact-level fault detection is realized.

The invention discloses a cable joint discharge monitoring system, which comprises a sensing layer, a data fusion layer and an analysis layer, and also discloses a cable joint discharge monitoring method, which comprises the following steps: monitoring the high-frequency current of a cable joint, acquiring a back Raman scattering signal of laser in a distributed optical fiber by an optical time domain reflection demodulation unit, obtaining the temperature of a measuring point, and monitoring the temperature of the cable joint. The analysis layer judges whether the temperature exceeds a temperature warning value or not, judges whether a high-frequency current pulse from the high-frequency current sensor is greater than a high-frequency current pulse warning value or not when the temperature exceeds the temperature warning value, and establishes a three-dimensional temperature field according to the temperature of the measuring point when the high-frequency current pulse is greater than the high-frequency current pulse warning value; the method comprises the following steps: acquiring a three-dimensional temperature field, performing spatio-temporal data alignment on the three-dimensional temperature field and high-frequency current acquired by a high-frequency current sensor, generating an abnormal region thermodynamic diagram, judging whether time and temperature data after alignment have interference or not, and performing three-dimensional positioning on a defective region and evaluating the severity of the defective region by an analysis layer when the interference does not exist.

The invention discloses a grounding resistance regular monitoring system and method, and belongs to the technical field of power equipment state monitoring. The system comprises a pulse generation module, a measurement module, a control module, a protection module and a communication module. The core lies in that a low-amplitude short-time-range direct-current pulse current is adopted to be injected into a grounding system, the pulse amplitude, width and frequency parameters are optimized to be always lower than the action threshold value of a relay protection device, and therefore accurate measurement is achieved on the premise that power is not cut off and misoperation is not caused. Meanwhile, historical data trend analysis and soil environment factors are fused, the deterioration trend of the grounding resistance is intelligently predicted, early warning is performed in advance, and a resistance reduction device can be linked for automatic adjustment. The method effectively solves the problems that a traditional measurement method needs power failure and is poor in interference resistance and an existing online monitoring technology is likely to trigger protection by mistake, and achieves safe, accurate, automatic and intelligent monitoring, operation and maintenance of the grounding resistance.

The invention relates to the technical field of electrical equipment state monitoring, and discloses an electrical equipment partial discharge positioning detection method. The method comprises the following steps: acquiring synchronous current pulse sequences and ultrasonic waveforms through a pulse current sensor and an ultrasonic sensor; calculating a signal delay inequality; establishing a sound wave propagation multi-path database based on the three-dimensional structure of the switch cabinet and the sensor coordinates; matching the ultrasonic shape features with a database to determine an actual propagation path and an equivalent distance; combining the delay inequality, the sensor coordinate and the equivalent distance, and iteratively solving the optimal space coordinate of the discharge point by adopting a particle swarm optimization algorithm; and mapping the coordinates to the topological graph to generate a positioning report. According to the method, the sound wave aliasing effect is decoupled through the pre-established multi-path database, the time delay correction and coordinate solving process is optimized, and the positioning precision and efficiency are remarkably improved.

The invention relates to the technical field of lamp bead active heat dissipation, and discloses an LED lamp bead active heat dissipation system and method, and the method comprises the steps: injecting a micro-current pulse into a PN junction of an LED chip through a constant current source, collecting a forward voltage drop sampling value, and collecting a substrate temperature sampling value; calculating a junction temperature value based on the forward voltage drop sampling value, and calculating a junction-to-case temperature difference value and a substrate temperature rise rate value; setting an early-warning state identifier when the junction-to-case temperature difference value exceeds an early-warning threshold value and the duration meets a preset duration, setting an alarm state identifier when the junction-to-case temperature difference value exceeds an alarm threshold value, and shielding thermal runaway detection when the substrate temperature rise rate value exceeds an environment thermal shock threshold value and the junction-to-case temperature difference value is smaller than an environment exclusion threshold value; when the state identification is the normal state identification, calculating a first compensation current value; and when the state identification is the early warning state identification, a second compensation current value is calculated, and when the state identification is the alarm state identification, an alarm current limiting value is calculated, so that the working stability and long-term reliability of the LED in a wide temperature range are ensured.