602 results about "Signal injection" patented technology

The invention relates to the technical field of electrical engineering and sensors, and provides a high-precision current sensor electrical performance detection method, which comprises the steps of collecting an original output signal of a current sensor and performing multi-dimensional signal preprocessing; extracting multi-dimensional feature parameters from the preprocessed signals based on a dynamic feature extraction algorithm; establishing a dynamic compensation model according to the multi-dimensional characteristic parameters, and generating a compensation control signal; a compensation control signal is injected into the detected current sensor to form closed-loop feedback, and a compensated output signal is collected; calculating a sensor performance degradation parameter according to the signal difference before and after compensation; an electrical performance assessment report is generated based on the performance degradation parameter. According to the invention, the measurement precision and reliability of the sensor can be improved, the service life is prolonged, the maintenance cost is reduced, and a powerful guarantee is provided for safe and stable operation of a power system and electronic equipment.

The invention provides a data transmission rapid verification method of a non-standard Type-C interface, which comprises the following steps: firstly, obtaining a verification request triggered when target equipment accesses the non-standard Type-C interface, extracting interface real-time signal characteristics including a voltage fluctuation sequence and the like based on the physical connection state identifier, and sending the extracted interface real-time signal characteristics to the non-standard Type-C interface; and then dynamically matching the real-time signal characteristics with a standard transmission parameter library, generating a test instruction set containing a priority ranking verification action and a trigger condition threshold value, calling the test instruction set to perform staged signal injection and feedback capture on the interface, recording an execution result and marking a time sequence, and finally generating a verification report according to the result. And the abnormal nodes which do not meet the transmission stability index are mapped to the interface physical structure defect description, so that rapid, comprehensive and accurate data transmission verification of the non-standard Type-C interface is realized.

The invention discloses a wireless communication anti-interference method and system based on data analysis, and belongs to the technical field of communication anti-interference, in the wireless communication anti-interference method and system based on data analysis, the active defense capability of the system to unknown interference is improved through virtual interference generation and physical suppression by linkage cooperation of a generative adversarial network and an adaptive beam forming algorithm. The generator continuously simulates a novel interference signal injection training environment, so that a beam forming algorithm learns in advance to form accurate null in an interference direction, and the response time when actual interference occurs is greatly shortened. Meanwhile, interference space features detected by the beam forming module in an actual scene reversely optimize a signal construction rule of the generator, and the matching degree of a generated sample and a real electromagnetic environment is enhanced. The dynamic mutual promotion mechanism not only enhances the timeliness of interference suppression, but also reduces the problems of signal quality fluctuation and excessive consumption of hardware resources caused by passive response in the traditional scheme.

The invention discloses an operation state fault monitoring method, system and device for a heavy-load overhead line, and relates to the technical field of electrical fault detection of the heavy-load overhead line. The method comprises the following steps: injecting a high-frequency test signal into a heavy-load overhead line to carry out predefined fault detection so as to obtain a total harmonic distortion rate; performing first harmonic optimization adjustment according to comparative analysis of the total harmonic distortion rate and a threshold value; performing harmonic second optimization adjustment according to the monitoring analysis result of the external load fluctuation of the heavy-load overhead line; and performing harmonic third optimization adjustment according to the monitoring analysis result of the external environment fluctuation of the heavy-load overhead line. According to the invention, through multi-stage distribution adjustment, the effect of improving the dynamic regulation and control accuracy of the high-frequency test signal injection fault monitoring method of the heavy-load overhead line in extreme weather is achieved; the problem of insufficient dynamic regulation and control accuracy of a high-frequency test signal injection fault monitoring method of a heavy-load overhead line in extreme weather exists.

The invention relates to the technical field of cable positioning, in particular to a one-way grounding fault positioning method based on a signal injection method. The method comprises the following steps: installing an impedance detection unit at a grounding knife switch of a transformer substation, and injecting a controllable AC signal into a power transmission line through a built-in injection coil to enable the line to be in an open circuit state; collecting the injected current signal and performing frequency enhancement to extract the amplitude and phase of a target frequency component; zero-sequence impedance is calculated based on the injection voltage and current, and the zero-sequence impedance is compared with a preset impedance model to judge single-phase grounding; and when a fault is detected, determining a fault distance, a tower position and a grounding phase according to an impedance difference matching result, thereby realizing accurate positioning. According to the invention, by injecting the controllable AC signal into the power transmission line and combining frequency enhancement, phase self-calibration and impedance difference matching analysis, high-sensitivity detection, high-stability signal extraction and high-precision positioning of the single-phase earth fault are realized.

The invention provides a core wire decoupling method for online monitoring of insulation damage of a multi-core cable and a signal electromagnetic coupling injection device, and the method comprises the steps: modulating a cable insulation damage monitoring signal in a time-frequency domain; injecting the modulated monitoring signal into a multi-core cable through an electromagnetic coupling method; reflection signals generated by the core wires at the cable insulation impedance discontinuous points are received respectively; calculating a system propagation coefficient according to the received reflection signal, analyzing the discontinuity degree of the cable insulation impedance, and obtaining a cable insulation impedance parameter group; if the impedance discontinuity degree is not greater than the given threshold value, injecting the modulated monitoring signal again after a given time interval; and if the impedance discontinuity degree is greater than a given threshold value, decomposing the distribution parameters of the insulation impedance through a multi-core impedance decoupling method, identifying the core wire with insulation damage, and positioning the position of the core wire. According to the invention, positioning and mode identification can be realized for conventional cable insulation damage, and the problems of positioning and damage condition identification of cable insulation damage monitoring are solved.

The invention discloses a micro-mechanical gyroscope zero offset online temperature compensation method based on Q value active control, and belongs to the technical field of micro-mechanical gyroscope zero offset temperature compensation. According to the method, on the basis that asymmetry of quality factors of a driving mode and a detection mode is a main cause of an in-phase zero offset error, improvement of in-phase zero offset is achieved in a mode of controlling the quality factors of the modes through parametric excitation. According to the method, online identification of the intrinsic quality factor and the equivalent quality factor of the detection mode is realized by using a signal injection method, and online compensation of the equivalent quality factor is realized through parametric excitation. The method solves the problem of zero offset error drift caused by mismatching of quality factors of a driving mode and a detection mode in a temperature change environment, and a universal scheme is provided for the zero offset temperature stability of the high-performance micromechanical gyroscope.

The invention relates to the technical field of power cable fault detection and positioning, in particular to a middle and high voltage cable insulation defect live detection and positioning method, which comprises the following steps: step 1, injecting a composite detection signal into a cable conductor through a signal injection device; 2, arranging signal acquisition devices at a plurality of preset point positions of the cable; step 3, carrying out adaptive processing on the acquired response signal; step 4, extracting insulation defect features from the response signals after adaptive processing; step 5, based on the extracted insulation defect features, classifying defect types by using a pattern recognition algorithm, and calculating defect positions based on a signal propagation time difference principle; and 6, outputting a defect identification and positioning result to a monitoring system, verifying, and if the deviation between the positioning result and historical data exceeds a threshold value, re-executing the steps 1 to 5. By combining a multi-point synchronous measurement technology and a precise space-time analysis method, the position where the defect occurs can be positioned more accurately.

The invention discloses a permanent magnet motor turn-to-turn short circuit fault diagnosis method considering complex working condition influence, belongs to the technical field of permanent magnet motor fault diagnosis, and aims to solve the problems that a turn-to-turn short circuit diagnosis result of a permanent magnet synchronous motor for an electric vehicle is easily influenced by working conditions and slight faults are difficult to diagnose under complex operation working conditions. The method comprises the following steps: step 1, high-frequency signal injection and information acquisition; injecting the high-frequency rotating voltage signal into a motor control system under a natural coordinate system, and collecting each phase of high-frequency current and each phase of high-frequency voltage of the motor through a band-pass filter; 2, subtracting the high-frequency voltage from the healthy voltage under the condition that the high-frequency signal is injected, and calculating to obtain a high-frequency voltage residual error of each phase; 3, according to the high-frequency voltage residual error of each phase, obtaining two fault characteristic quantities, namely the standard deviation of the high-frequency voltage residual error and the absolute average value of the high-frequency voltage residual error of each phase; and 4, judging whether a turn-to-turn short circuit fault occurs or not according to the fault characteristic quantity, and judging a fault phase.

The invention specifically relates to a standardized fuse fault monitoring and diagnosis system, and relates to the technical field of power system protection equipment monitoring. A signal processing and impedance spectrum calculation module; an intelligent diagnosis and state evaluation module; and a benchmark management and personalized tracking module. According to the invention, controllable micro test signals are actively injected to obtain frequency domain impedance fingerprints, and accurate capture of microscopic degradation is realized; non-intrusive coupling and signal injection are adopted, the topology of a main loop does not need to be changed, the inherent protection characteristic of the fuse is guaranteed, and power frequency interference can be penetrated; the recognition amount of budding faults such as contact oxidation and melt corrosion is improved in advance, and power failure accidents caused by fault expansion are avoided.

The invention relates to the technical field of micro-grids, and provides a network construction type energy storage system reconstruction method and system based on dynamic impedance matching, and the method comprises the steps: obtaining the real-time impedance and real-time reactance of an associated power grid through a high-frequency disturbance signal injection decoupling mode; meanwhile, according to the voltage phase angle and the voltage drop depth of the associated power grid, respectively obtaining a phase compensation item and a dynamic adjustment coefficient, so as to dynamically adjust the virtual impedance through the phase compensation item and the dynamic adjustment coefficient; and real-time output of the target energy storage system is regulated and controlled by combining closed-loop control of the impedance outer loop and the voltage inner loop, so that voltage offset and broadband oscillation of the associated power grid are suppressed. According to the invention, the phase compensation item obtained according to the voltage phase angle and the dynamic adjustment coefficient obtained according to the voltage drop depth are added to the calculation of the virtual impedance, and the closed-loop control of the impedance outer loop and the voltage inner loop is combined, so that transient impact suppression and oscillation suppression can be realized at the same time, the limitation of separate triggering is effectively avoided, and the reliability of the system is improved. And the power grid voltage stabilization control effect is improved.

The invention relates to an electrostatic vibrating diaphragm automobile audio which is mainly used for an electric vehicle and can compensate vehicle-mounted electromagnetic interference audio and solve the problem of electromagnetic interference of a motor PWM switch and rotating speed harmonics on an audio system. The electrostatic diaphragm automobile sound system comprises an electrostatic diaphragm loudspeaker and an interference feature extraction module, the rotating speed of a motor and the PWM frequency are obtained through a CAN bus, and a dynamic interference feature set is analyzed and extracted through adaptive window length FFT; the EMI quantification module is used for calculating an electromagnetic pollution index at a frequency band of 8kHz-20kHz, and triggering compensation when the electromagnetic pollution index exceeds a threshold value of-40dB; the dynamic notch compensation module is used for generating an inversion signal; according to the double-loop feedback control module, the amplitude is adjusted through PID of an inner loop, and the phase is optimized through gradient descent of an outer loop so as to minimize THD. The method comprises five steps of signal acquisition, feature extraction, interference quantification, dynamic compensation and signal injection. Interference frequency drift can be accurately tracked, a tone quality MOS value is improved after compensation, and an over-compensation risk is avoided.

The invention relates to the technical field of power system protection, in particular to an underground power distribution network single-phase grounding protection system and method based on a signal injection method. The system comprises a signal acquisition module, a measurement and control protection module and an online monitoring module. According to the invention, by injecting the independent direct current signal and combining a zero-sequence fundamental wave time sequence identification algorithm and a traveling wave distance measurement method, rapid detection, high-precision positioning and selective protection of the single-phase earth fault of the underground low-voltage power distribution network are realized, and the method is suitable for complex environments such as coal mines and metal mines; through insulation value on-line monitoring and electric leakage protection, the ground insulation value level of a line is reflected to the voltage change of an additional direct current signal and a reactor neutral point. A zero-sequence fundamental wave time sequence identification model is adopted for electric leakage fault judgment so as to judge the fault type. By outputting a relay signal, on-off control is performed on a protected branch, so that a fault line can be quickly cut off when a fault occurs, and equipment and a bus are protected from being damaged by the fault.

The invention discloses a cable copper shielding layer damage and damage opening size detection method, system and device based on the combination of a frequency doubling measurement method and a step-by-step evaluation method and a storage medium, and is applied to the technical field of power equipment state detection. Comprising the following steps: respectively acquiring measurement results of a cable to be measured under Chirp signal injection of Gaussian envelopes with single and double center frequencies, and determining the starting time of an injection signal and the arrival time of a reflection signal according to an extreme value in a time-frequency cross correlation curve; extracting an injection signal and a reflection signal by taking the starting time and the arrival time as extraction starting points and the length of the injection signal as an extraction width, and calculating the damage degree according to the spectrum ratio of the reflection signal to the injection signal; and calculating characteristic impedance based on the damage degree, and sequentially determining the size and length of the central angle of the cable copper shielding layer damage port by using a step-by-step evaluation method. According to the invention, effective detection and positioning of copper shield damage and effective estimation of the damage size are realized.

The invention discloses a permanent magnet synchronous motor full-speed-domain position-sensorless hybrid control method and a permanent magnet synchronous motor full-speed-domain position-sensorless hybrid control system, and the permanent magnet synchronous motor full-speed-domain position-sensorless hybrid control method is constructed by taking a permanent magnet synchronous motor nonlinear dynamic system model as a starting point. A hybrid control method combining high-frequency pulsating square wave signal injection under a linear dynamic system model, a rotor polarity judgment and rotor initial position estimation algorithm and an unscented Kalman filtering extension algorithm in an additive noise form under a nonlinear discrete dynamic system model is adopted; and obtaining the optimal estimation observation value of the system state variable in the static, low-speed, medium-speed and high-speed full-speed domain range under the condition that the permanent magnet synchronous motor is not provided with a mechanical position sensor. The optimal estimation observation value is used for compensating and feeding back a permanent magnet synchronous motor drive control system adjusting strategy, disturbance of load torque is improved, the noise amount and disturbance amount introduced by three-phase current measurement are eliminated, and efficient and accurate control operation of the permanent magnet synchronous motor is achieved.

The invention discloses a parameter identification-based synchronous reluctance motor full-speed-domain position-sensorless control method, which relates to the technical field of motor control, and is characterized in that when a motor is in a zero-low-speed domain, a pulsating square wave voltage signal injection method is adopted to realize effective observation of a rotor position and good dynamic response performance; when a rotating speed transition interval is entered, an improved weighted switching strategy is adopted, so that the motor can smoothly switch two control strategies in the interval; when the motor enters a medium-high speed domain, rotor position angle observation is carried out by adopting a model reference adaptive control method, and high steady-state operation precision is achieved; however, in the whole operation process, inductance parameters influenced by magnetic circuit saturation and cross saturation are nonlinear, online identification is carried out by adopting a model reference adaptive method, and the estimation precision of the rotor position angle is improved.

The invention discloses a permanent magnet synchronous motor sensorless control method based on a dynamic position error. A transition stage is provided, per-unit estimation position errors between a first position error signal obtained based on a high-frequency signal injection method and a second position error signal obtained based on a sliding mode observer are compared, an optimal switching speed point is dynamically determined, smooth fusion is carried out on the two position errors by using a nonlinear weighting function, and the optimal switching speed point is obtained. And finally, the estimated position and rotating speed are obtained through a phase-locked loop. And finally, position tracking is carried out by adopting different error signals according to the estimated rotating speed. According to the method, the problem of estimation value pulsation and jump caused by the fact that a traditional method depends on fixed experience switching points is solved, smooth and self-adaptive switching of the two estimation methods in the full-speed domain range is achieved, the control precision and operation stability of the system are remarkably improved, the structure is simple, and engineering implementation is easy.

The invention provides an automatic driving perception system reliability test method based on fault injection, which can be applied to the technical field of automatic driving vehicles, and comprises the following steps: constructing a key scene library; matching a test scene from the key scene library according to a reliability test requirement of a sensing system function claimed by a manufacturer; analyzing a fault mode corresponding to the sensing system function in the test scene, and determining a key sensor to be subjected to fault injection and a fault signal; injecting the fault signal into the key sensor signal to obtain a sensing signal with a fault; testing the sensing system based on the sensing signal with the fault to obtain the reliability of the function of the sensing system; and the total reliability and the reliability level of the sensing system are obtained. By injecting a fault into a key sensor in a test scene, the performance of a sensing system under an abnormal condition is studied, and the reliability of the sensing system is effectively evaluated.

The invention discloses a dual three-phase permanent magnet synchronous motor maximum torque current ratio control method and system based on virtual signal injection, and the method comprises the steps: injecting a bipolar square wave signal into a current vector angle, and calculating the d-q axis current after the bipolar square wave signal is injected through the current vector angle of the bipolar square wave signal; the d-q axis current after the bipolar square wave signal is injected is substituted into the corrected torque equation, the positive polarity torque Tup and the negative polarity torque Tdown of the dual three-phase permanent magnet synchronous motor are calculated and are expanded according to the Taylor series, when the difference between the Tup and the Tdown expanded according to the Taylor series is equal to 0, the difference between the Tup and the Tdown passes through a PI controller and then is superposed with an initial current vector angle beta, and the initial current vector angle beta is obtained. And obtaining a current optimal current vector angle, and calculating a d-q axis reference current required by the dual three-phase permanent magnet synchronous motor. According to the invention, accurate control of the maximum torque current ratio is realized.

The invention provides a mining motor no-load and load characteristic test analysis method and system, and relates to the field of intelligent image analysis, a Hall array sensor is arranged on a motor stator tooth portion to collect air-gap magnetic field distribution data, and a high-frequency signal injection method and a wavelet singular value decomposition technology are combined, so that the load characteristic of a mining motor is obtained. The air gap magnetic field distortion degree and the air gap dynamic eccentricity index are accurately calculated, and meanwhile a load dynamic compensation coefficient is generated to correct the motor output torque. Therefore, the dynamic characteristics of the motor in the no-load and load states can be comprehensively reflected, the accuracy of the load capacity evaluation of the mining motor is improved, and potential problems in the operation of the motor can be found in time, so that the performance of the motor is optimized, the service life of the motor is prolonged, and the safety and reliability of mining production are improved.

The invention discloses a synchronous motor sensorless control method based on a Newton-Raphson predictive phase-locked loop, and relates to the technical field of motor control. The invention aims to solve the problems that an existing position-sensorless control method is limited by extra loss and noise caused by high-frequency signal injection in the aspect of position signal extraction and poor dynamic performance caused by a traditional phase-locked loop technology, and a prediction phase-locked loop technology needs a large amount of iterative operation for solving a cost function. According to the method, the flux linkage estimation value of the alpha-beta coordinate system is observed, the filtered flux linkage estimation value of the alpha-beta coordinate system is reconstructed, and then a cost function is constructed; when the number of iterations in the current motor control period does not reach the maximum, updating a rotor position angle by using a Newton method, and further updating a cost function; and when the number of iterations in the current motor control period reaches the maximum, calculating a convergence angle in the current motor control period by using an improved Newton method, and calculating an angular velocity estimated value, thereby realizing position-sensorless control of the synchronous motor.

The invention discloses a grounding detection method and device based on a signal injection technology, and belongs to the technical field of grounding fault detection, and the method comprises the steps: S1, setting a detection signal parameter based on the historical operation data of a to-be-detected circuit, and generating a detection signal through the grounding detection device based on the signal injection technology; s2, adjusting the detection signal based on the detection signal parameter to obtain an optimal detection signal, and inputting the optimal detection signal into the circuit to be detected; s3, after the optimal detection signal is input into the to-be-detected circuit, detection data are collected based on the loop structure of the to-be-detected circuit; s4, performing ground fault analysis based on the detection data, and determining a ground loop in the to-be-detected circuit according to a corresponding relation between the detection data and the loop structure of the to-be-detected circuit and a ground fault analysis result; according to the invention, the problem of low detection result accuracy caused by the fact that the influence of the injection signal frequency on the detection device is not considered in the prior art is solved.

The invention provides an electromagnetic compatibility test system for an integrated circuit, a part or a whole vehicle. The system comprises an interference signal injection or receiving device, a test board, an oscilloscope, an upper computer, a power supply and an isolation communication device, the interference signal injection or receiving device is used for sending a quantitative interference signal to the test board or receiving and measuring the size of the interference signal of the test board; the test board is used for bearing a tested integrated circuit and carrying out an electromagnetic compatibility test according to a working state specified by the upper computer; the isolation communication device is used for performing photoelectric conversion on a control signal and a monitoring signal corresponding to the electromagnetic compatibility test to form photoelectric isolation; the oscilloscope is used for measuring the waveform of the monitoring signal; and the upper computer is used for controlling the test process and analyzing the monitoring signal to judge the test result. The isolation communication device is used for cutting off electrical connection between the test board and the upper computer and the oscilloscope, it is ensured that the test board is not affected by the outside in the electromagnetic compatibility test process, and the accuracy of the electromagnetic compatibility test is improved.

The invention relates to an MMC reactive power support capability improvement method considering a dynamic boundary under a power grid fault, and belongs to the field of flexible DC power transmission control, and the method comprises the steps: constructing an MMC dynamic boundary calculation unit under the power grid fault; constructing a fitting function of a zero-sequence signal calculation unit for improving the reactive support capability of the MMC; whether the zero-sequence signal calculation unit is started or not is judged on the basis of reactive power Q0. Max and Q1. Max which are output by the constructed dynamic boundary calculation unit and have no zero-sequence signal injection and reactive power Qdet detected in real time in the system; and if the zero-sequence signal calculation unit is started, calculating a zero-sequence signal of an expanded operation domain of the MMC under the current working condition in real time, and injecting the zero-sequence signal into the MMC modulation module, thereby realizing improvement of the reactive support capability of the MMC. According to the method, the reactive power supporting capability of the converter can be improved, the risks of power grid collapse and system oscillation are reduced, the dynamic boundary of the converter under the power grid fault is considered, and the method has flexibility, real-time performance and economical efficiency.

The invention discloses an on-line insulation monitoring system and method for a national railway vehicle, and relates to the technical field of on-line insulation monitoring, and the system comprises a detection signal injection module which is used for injecting a preset broadband active detection signal, and synchronously collecting a response signal set transmitted through a vehicle body grounding network; the fingerprint feature construction module is used for constructing network fingerprint features in a current insulation state; the spatial distribution atlas acquisition module is used for carrying out inversion calculation to obtain an admittance spatial distribution atlas of the whole vehicle; and the insulation abnormal area identification module is used for identifying an insulation abnormal area. According to the invention, the technical problems of long troubleshooting time and poor accuracy caused by incapability of online real-time monitoring of the insulation state of the vehicle body grounding network of the national railway vehicle and low abnormal area positioning precision in the prior art are solved, and online monitoring of the insulation state of the vehicle body grounding network of the national railway vehicle and accurate positioning of the abnormal area are realized. And the efficiency and the accuracy of insulation fault checking are improved.

The invention provides an automobile electronic control unit fuzzy testing method based on partial code coverage rate feedback and a computer, and belongs to the technical field of automobile electronic control unit code testing. The computer performs static analysis on source codes of the automobile electronic control unit, identifies inevitable execution blocks and conditional execution blocks, performs selective instrumentation on the conditional execution blocks, and inserts coverage rate recording instructions of the conditional execution blocks. And the computer source code is loaded into the automobile electronic control unit, and a test input signal is generated through the fuzzy test engine and is injected into the automobile electronic control unit. In the process of executing the program by the automobile electronic control unit, recording the coverage condition of the condition execution block to a bitmap in the memory; the computer reads the coverage rate data of the condition execution block through the debugger every time a complete execution cycle is completed; and the fuzzy test engine adjusts the input generation strategy according to the coverage rate data feedback of the condition execution block and tests again. According to the method, the automobile electronic control unit source code fuzzy test coverage condition is efficiently collected.

The invention discloses a direct-current cable single-pole grounding fault distance measurement method based on instantaneous power curve slope change, relates to the technical field of electrics, and has the advantages that external signal injection is not needed, positioning is realized directly through dynamic slope change of a power curve, the problems of complicated equipment and poor anti-interference performance of a traditional traveling wave method are solved, and the positioning accuracy is improved. According to the technical scheme, the method comprises the following steps that A1, voltage and current signals of conductor layers of a positive electrode and a negative electrode are obtained; a2, calculating a primary slope S0; a3, calculating an equivalent time point tz; a4, the maximum secondary slope pmax is calculated; a5, calculating a constant alpha and correction coefficients lambda and k; a6, an actual secondary slope pavg is obtained; and A7, obtaining a fault distance x. According to the method, the instantaneous power change of the head end of the cable is monitored, and the dynamic change of the power slope is combined, so that the fault position can be accurately identified in real time.

The invention relates to the technical field of fault detection, in particular to an electronic component fault management method and system. The method comprises the following steps: collecting real-time data and constructing a real-time fault monitoring data set; reading historical data and constructing a historical reference data set; comparing the real-time fault monitoring data set with the historical reference data set item by item in a corresponding time window to obtain a drift amplitude, and mapping according to the drift amplitude to generate a reverse excitation amplitude instruction; a reverse current signal according to the reverse excitation amplitude instruction is injected into the loop node to be measured, and a Hall null drift amount is determined according to Hall output; outputting an electronic disturbance quantity based on the Hall null drift quantity; therefore, through dynamic data cooperation and an active excitation response mechanism, the problems of missing detection recessive degradation, misjudgment transient interference and single diagnosis dimension of traditional fault management are solved, and the hidden danger recognition precision and the protection reliability are remarkably improved.

The invention discloses a permanent magnet synchronous motor temperature monitoring and demagnetization early warning method based on chaotic signal injection and multi-parameter fusion. Comprising the steps of 1, generating a wide-spectrum chaotic signal based on a Lorenz chaotic system, and injecting the wide-spectrum chaotic signal into a d-axis voltage channel of a d-q-axis mathematical model of the permanent magnet synchronous motor; 2, identifying stator resistance RS and d-axis inductance Ld by using a least square method; 3, a Kalman state space model with the winding temperature Tw and the magnetic steel temperature Tm as state variables is constructed, the resistance Rs and the inductance Ld which are measured in real time are fused, the observation noise covariance R is adjusted in a self-adaptive mode, and the winding temperature Tw and the magnetic steel temperature Tm are output in a decoupling mode; step 4, establishing a motor back electromotive force model to calculate a real-time flux linkage psi f, and calculating a motor temperature rise rate # imgabs0 # through a sliding window weighted average method; and step 5, performing demagnetization risk grading early warning according to the flux linkage and the temperature rise rate of the motor.

A wearable Doppler blood flowmeter can be used with an inflatable cuff to measure blood flow, such as for assessing peripheral artery disease (PAD). The present approach can include techniques such as providing or using a wearable acoustic Doppler blood flowmeter, without requiring the intricate manipulation of a handheld Doppler probe. The system can select a pair of acoustic transmitter and acoustic receiver from a set of more than two transducers, including one or more of different locations, orientations, or spacings, such as to vary a targeted region. The RF echo response signal can be translated to an audio response signal. An audio response signal injection circuit can adaptively inject a noise or other enhancement signal, such as to help improve perceptibility of an audible characteristic of pulsatile arterial blood flow. A trained machine learning model can be employed to select or adjust operating settings, to assess diagnostic information, or both.