316 results about "Zero crossing" patented technology

The invention relates to the field of ring main units, in particular to an event-driven intelligent ring main unit and a control method, and the event-driven intelligent ring main unit comprises a cabinet body, a cabinet body built-in circuit breaker, an isolation grounding switch and a fusion sensing array. An array synchronously acquires mechanical and electrical quantities, an edge decision-making system takes a voltage zero crossing point as an absolute time mark nanosecond alignment event, a closed-loop control core generates a protection and topology reconstruction instruction in situ according to the event, and primary equipment is driven in a millisecond level; the intelligent communication interface dynamically schedules bandwidth according to the data priority, and key instructions are ensured to be issued in real time. According to the invention, the problems of fault misjudgment and local control delay caused by lack of a unified time sequence reference in a mechanical state and an electrical transient state of a traditional ring main unit are solved.

The invention discloses a multi-parameter measurement system and method for a power frequency non-partial discharge test transformer, and relates to the technical field of state monitoring of high-voltage test equipment and power equipment, and the system comprises a synchronous trigger unit which is connected to a power frequency voltage signal collection end and is used for detecting a zero crossing point of a power frequency voltage signal and generating a synchronous trigger signal, a power frequency period is divided into a plurality of sub-windows with equal phase angles. According to the multi-parameter measurement system and method for the power frequency non-partial discharge test transformer, the problem of phase mismatch of a power frequency signal and a high-frequency partial discharge signal in traditional multi-parameter measurement is effectively solved through a power frequency phase locked synchronous trigger mechanism and a dynamic noise suppression technology; and the positioning precision of the partial discharge source and the insulation defect diagnosis reliability are improved. The nanosecond-level time sequence error control is realized, and the power frequency coupling interference is inhibited while the details of the high-frequency pulse are kept by combining a phase correlation dynamic filtering strategy, so that the signal-to-noise ratio of the weak discharge signal is improved.

The invention discloses an automatic anchor point searching and processing method for grid-connected test data of a photovoltaic inverter, and belongs to the technical field of automatic test of a power system. According to the method, a three-phase voltage and current signal output by a power grid simulator and an inverter power instruction signal are aligned through a high-precision time synchronization device; wavelet transform multi-scale noise reduction and moving average filtering combined preprocessing is adopted to improve the signal-to-noise ratio; identifying a voltage zero crossing point candidate set, a drop starting point candidate set and a recovery termination point candidate set based on a self-adaptive dynamic threshold value; transient energy characteristic verification is introduced for a voltage drop starting point; effective anchor points are confirmed through time window association of power instruction step changes. According to the method, the problems of low efficiency of manual key event point identification, misjudgment caused by noise interference, grid event and inverter response time sequence correlation missing and the like are solved, and the automation degree of test data analysis, anchor point positioning precision and control response time sequence analysis reliability are remarkably improved.

The invention discloses an accurate zero crossing point control method for a built-in relay of a large-current electric energy meter, which relates to the technical field of power electronics and intelligent metering and comprises the following steps of: receiving a power grid voltage digital signal, determining a voltage zero crossing point by comparing symbol changes of adjacent sampling values, establishing a phase corresponding relation between voltage and current, and calculating a current phase corresponding relation; generating current zero crossing point prediction data; when a relay switching instruction is received, the specific moment of the next current zero crossing point is calculated, and the control signal sending moment is determined; a relay driving control signal is sent, the actual action completion moment of the relay is collected, the deviation from the expected zero crossing moment is calculated, and the mechanical action delay time parameter of the relay is corrected. By predicting the current zero-crossing time and considering the mechanical action delay characteristic of the relay, accurate switching of the built-in relay at the actual current zero-crossing point is achieved, meanwhile, the self-adaptive adjusting capacity is achieved, the arc energy during large-current switching is reduced, the service life of the relay is prolonged, and the reliability of the electric energy meter is improved.

The invention discloses a power capacitor bank dielectric loss on-line monitoring method, particularly relates to the technical field of power system equipment insulation state monitoring, and is used for solving the problems of insufficient signal synchronization precision and large dielectric loss calculation error under complex electromagnetic interference in the existing method. The method comprises the following steps: acquiring voltage and current signals in real time and dynamically tracking fundamental frequency; intercepting a main period waveform, constructing phase space trajectory analysis complexity, and generating distortion features in combination with symbol sequence transfer entropy; dynamically adjusting filtering parameters based on the distortion characteristics and the Lyapunov exponent gradient; calculating a high-precision phase difference through zero crossing point interpolation correction and sliding window filtering, and finally determining a dielectric loss value; through dynamic frequency tracking, nonlinear feature collaborative analysis and an adaptive filtering strategy, noise interference is effectively suppressed, phase synchronization precision and dielectric loss calculation reliability are improved, and accurate and real-time monitoring support is provided for insulation performance evaluation of the power capacitor bank.

The invention relates to the technical field of voltage transformers, in particular to a voltage transformer real-time monitoring system based on broadband and edge calculation, which comprises the steps of collecting multiple paths of voltage transformer data, extracting peak values and zero cross points, comparing jump rising edge time differences, unifying time sequences, extracting extreme values and slope identification disturbance sections, and monitoring the voltage transformers in real time. Measuring amplitude continuous change to judge the offset trend, analyzing trend direction classification waveform fragments, and combining the three indexes to generate an operation state label. According to the method, a unified time sequence is constructed by comparing cross-channel jump rising edge time differences, multi-channel jump process alignment is achieved, the synchronous anomaly recognition capability is improved, the number of extreme values and the slope direction are extracted to recognize a disturbance dense section, continuous anomaly is judged by combining statistics of overrun, and the fluctuation trend is judged by tracking the deviation trend between extreme values. And based on the three-index combination classification operation state, the anomaly identification precision is improved.

The invention discloses a low-frequency load shedding method and system based on zero crossing point real-time frequency tracking, and the method specifically comprises the steps: setting a dynamic time window according to the power frequency characteristics of a sensing signal, and removing an abnormal zero crossing point exceeding the dynamic time window; matching a pre-stored harmonic feature library, establishing a mapping relation between a harmonic mode and a phase offset, and performing adaptive phase compensation on a pseudo zero crossing point of the sensing signal; a sensing signal, PMU phasor data and meteorological parameters are input into a three-dimensional convolutional neural network, a cross-modal incidence matrix is calculated through a self-attention mechanism, a future frequency change trajectory is predicted in combination with an LSTM unit, and an optimal load shedding strategy is output; and based on the optimal load shedding strategy, in combination with a forward acceleration criterion and reverse fault locking, executing emergency load shedding according to load importance grading. The technical bottleneck of a traditional low-frequency load shedding device is effectively solved, and the performance and reliability of frequency stability control of the power system are remarkably improved.

The invention relates to the technical field of industrial detection, and discloses a quality detection method, system and equipment based on a metal ingot and a storage medium. The method comprises the following steps: acquiring an RGB metal ingot image and a depth metal ingot image corresponding to each metal ingot to be detected on a casting production line; inputting the acquired RGB metal ingot images into the metal ingot surface defect target detection network model to obtain surface defect type confidence; preprocessing the metal ingot image of each depth; obtaining the surface space defect confidence coefficient according to the metal ingot surface depth data and the zero cross point of each curvature change; according to the surface defect type confidence coefficient and the surface space defect confidence coefficient, the comprehensive confidence coefficient of the to-be-detected metal ingot is obtained, and if the comprehensive confidence coefficient exceeds a preset fusion threshold value, it is determined that the to-be-detected metal ingot is a waste ingot. The to-be-detected metal ingot is detected according to the comprehensive confidence coefficient, and the detection efficiency is improved.

The invention discloses an equipment working state recognition method based on a voiceprint recognition model, and relates to the technical field of industrial equipment operation state recognition. The equipment working state recognition method based on the voiceprint recognition model comprises the following steps: collecting operation audio waveform data of target equipment, extracting acoustic representation data containing parameters such as short-time energy, a frequency spectrum centroid, a spectrum flux, MFCC and a zero crossing rate, inputting the acoustic representation data into a pre-trained voiceprint recognition model to extract voiceprint feature representation vectors, and carrying out voiceprint feature representation on the target equipment; according to the method, the audio signal is divided into the frames, the acoustic features such as short-time energy, spectrum centroid, spectrum flux, MFCC and zero crossing rate are extracted, the inter-frame evolution relation is modeled in combination with the bidirectional neural network, and the attention mechanism is introduced to highlight the key frame segment, so that the real-time performance of the audio signal is improved, and the real-time performance of the audio signal is improved. The recognition capability of working conditions such as fuzzy state boundary or unobvious transition is effectively enhanced, and the time sequence analysis and state judgment precision is improved.

The invention provides a real-time electroencephalogram phase locking closed-loop stimulation method and system, and relates to the technical field of electroencephalogram signal processing. The method comprises the following steps: firstly, acquiring a cortex electrical activity signal and establishing a baseline statistic, then carrying out causal band-pass filtering on the signal, and carrying out sampling and holding substitution in a stimulation artifact window; setting an amplitude and a duration threshold based on the baseline, and performing phase judgment after conditions are met; estimating an average period through zero crossing and calculating an instantaneous phase; outputting a trigger instruction when the three-point crossing judgment is established; and outputting stimulation under the constraint of charge balance and a safety limit value, setting a minimum prohibition period and link abnormity suppression, and recording a hit rate and a response rate for quality evaluation. According to the method, through causal phase estimation, artifact isolation and a schedulable triggering mechanism, the high hit rate of non-stationary signal phase locking stimulation is achieved, and the safety and effectiveness of a stimulation system are ensured.

The invention discloses a power frequency phase adaptive acquisition device, and relates to the technical field of electric power signal measurement, the device acquires electric field data at a gap through an electric field sensor integrated on an edge shell, calculates electric field intensity fluctuation, and generates interference diagnosis information in combination with a preset interference determination threshold value; when the interference diagnosis information shows that effective interference exists, the electric field intensity variable quantity is calculated, a mapping model is established based on a proportionality coefficient obtained through an experiment so as to obtain zero crossing point offset, and the sampling trigger moment of a zero crossing point detection module is corrected; the clock synchronization module calculates a phase difference by taking the corrected trigger moment as a reference, dynamically adjusts a calibration frequency by combining a phase difference threshold value, and outputs a synchronized system clock signal; and the control system takes the synchronized system clock signal as a trigger signal, collects power frequency phase data according to a power frequency period, and stores the power frequency phase data to a database through a transmission unit, thereby realizing high-precision power frequency phase collection.

The invention provides an energy storage converter low-voltage ride-through control method and an energy storage converter, and relates to the field of low-voltage ride-through control, and the method comprises the steps: obtaining a three-phase line voltage of a power grid; based on the three-phase line voltage, calculating a coordinate transformation angle by using a phase-locked loop method of a second-order generalized integrator to obtain a first coordinate transformation angle; based on the three-phase line voltage, calculating a coordinate transformation angle by using a phase-locked loop method of BC phase line voltage zero crossing point detection to obtain a second coordinate transformation angle; calculating an absolute value of a difference value between the first coordinate transformation angle and the second coordinate transformation angle to obtain a transformation angle difference value; judging a power grid voltage drop condition; and determining a target coordinate transformation angle and target reactive current positive sequence and negative sequence component given values according to the power grid voltage drop condition and the transformation angle difference value. According to the method provided by the invention, the low-voltage ride-through requirements under different power grid voltage drop conditions can be met, and the low-voltage ride-through capability and the system stability of the energy storage converter are improved.

The invention discloses an instrument electric signal detection system, which comprises a signal acquisition module, a signal processing module, a data display module and a data storage library, and relates to the technical field of electric signal detection. According to the instrument electric signal detection system, the voltage waveform curve graph is established according to the converted digital signals, the change trend of the corresponding digital signals is determined according to the curve processing algorithm, a plurality of zero crossing points in the change process are searched, then curve segmentation operation is carried out with each zero crossing point as a node, and the segmented curves are covered. According to the method, the signal change period is determined, and the corresponding calculation period is compared with the set period of the output source, so that the electric signal detection efficiency is improved, meanwhile, the accuracy of a data result is verified, the detection operation can be quickly distinguished aiming at waveform change data, and actual application is facilitated.

The invention provides an intelligent phase control vacuum circuit breaker health degree assessment method and device and a circuit breaker, and relates to the technical field of circuit breaker health assessment, and the method comprises the steps: carrying out the vacuum degree detection of an arc extinguish chamber in an intelligent phase control vacuum circuit breaker, and obtaining the vacuum degree; performing heating analysis on the vacuum circuit breaker according to the vacuum degree to obtain a heating parameter, and performing zero crossing point monitoring error analysis to obtain a zero crossing point error coefficient; according to the operation time parameter of the vacuum circuit breaker, mapping to obtain a mapping zero-crossing point error coefficient, calculating to obtain a zero-crossing deviation coefficient, and according to the zero-crossing deviation coefficient and an analysis deviation coefficient of heating analysis and zero-crossing point monitoring error analysis, carrying out confidence degree processing to obtain a zero-crossing confidence degree; and distributing a weight according to the zero-crossing confidence coefficient, and performing health degree calculation based on the vacuum degree and the zero-crossing point error coefficient to obtain the health degree of the vacuum circuit breaker. The technical problem of inaccurate health degree evaluation of the intelligent phase-controlled vacuum circuit breaker in the prior art is solved.

The invention is suitable for the technical field of power grid relay protection, and provides a synchronous sampling method, electronic equipment and a computer program product, and the method comprises the steps: generating a voltage and current waveform at a fixed sampling rate under a specified sampling clock frequency for a specified power grid; based on the zero crossing points of the voltage waveform with the fixed sampling rate and sampling points of the synchronously sampled voltage waveform (obtained by interpolation based on an initial value of stepping interpolation), calculating a synchronous sampling error among a plurality of zero crossing points in real time, and determining the correction of the current stepping interpolation; based on the correction amount and the initial value of the stepping interpolation, correcting the size of the current stepping interpolation to obtain a target value of the stepping interpolation; and respectively acting the target value of the stepping interpolation on the current waveform and the voltage waveform with the fixed sampling rate, and changing the sampling rate of the output waveform so as to obtain a new synchronous sampling waveform. According to the invention, the frequency change of the voltage can be quickly responded, and the precision of synchronous sampling is ensured by adjusting the stepping interpolation in real time.

A method for reducing reflected radio frequency (RF) power is described. The method includes receiving a voltage signal from an output of a match. The method further includes dividing the voltage signal into a plurality of bins and identifying a bin from the plurality of bins that includes a zero crossing. The bin is associated with a frequency of a high frequency (HF) signal. The method also includes applying a fixed multiplier to the frequency of the HF signal to generate a plurality of offsets. The method includes operating an HF RF generator according to the plurality of offsets during a time period in which the voltage signal is positive or negative.

The invention discloses an Internet of Things flowmeter data compression sensing transmission optimization method and system, particularly relates to the field of low-power-consumption wireless communication networks, and is used for solving the problem of compressed sensing signal distortion caused by sampling time sequence misalignment in an LPWAN bandwidth limited environment. Constructing a local phase reference by extracting a pipeline vibration fundamental frequency component, and receiving a cloud synchronization reference timestamp alignment signal; fundamental frequency and third harmonic components are separated to calculate arrival time difference, and a phase-locked loop is triggered to dynamically adjust the phase of a sampling clock based on a pipeline material threshold value; after the stability of the zero crossing point time variance is verified, compressed sensing sampling is performed on the flow signal by adopting a phase synchronous clock, and an optimized compressed measurement value is generated and transmitted to the cloud through the LPWAN; through closed-loop cooperation of physical characteristics and a communication clock, complete capture of a signal sparse structure is guaranteed under a low-bandwidth condition, and cloud reconstruction precision is significantly improved.

The invention relates to the technical field of power system relay protection, in particular to a power transmission line single-end fault positioning method and system. The method comprises the following steps: taking an envelope zero crossing point of an initial transient traveling wave signal as an attenuation ending moment; taking the moment from the occurrence moment of the initial transient traveling wave signal to the attenuation ending moment as an analysis time window; taking the duration of the analysis time window as the attenuation duration of the initial transient traveling wave signal; taking the maximum energy peak value as a resonant frequency identification reference threshold value, searching whether the energy of other frequency peak values greater than the resonant frequency identification threshold value exists or not, and if so, judging whether the initial transient traveling wave signal has resonant interference or not based on the attenuation duration of the initial transient traveling wave signal; if yes, designing a filter for the frequency component, and filtering the initial transient traveling wave signal; and obtaining a fault positioning result of the power transmission line based on the filtered transient traveling wave signal. According to the invention, the single-end fault positioning precision is effectively improved.

The invention discloses a fault diagnosis method, device and equipment for an NPC three-level inverter and a medium, and relates to the technical field of inverter fault diagnosis, and the method comprises the steps: building a fault stator current analysis model according to a fault stator current change rule of the inverter; a fault phase and a fault bridge arm are extracted and positioned by using a sliding window averaging method; and calculating and setting a fault positioning reference value under an ideal condition, and comparing the fault positioning reference value with a fault positioning actual value under an actual condition to position a faulted IGBT (Insulated Gate Bipolar Translator). A fault stator current analysis model is established to simulate a set current change condition under an ideal condition, a fault positioning reference value is calculated, and whether an actual fault condition is consistent with a set ideal fault condition is distinguished by a deviation between the fault positioning reference value and a fault positioning actual value of an actual condition, and whether a fault is an inner pipe or an outer pipe is positioned. During calculation, a current mean value from a fault moment to a first zero-crossing moment is utilized, a fault IGBT can be positioned in a fundamental wave period, and fault diagnosis and positioning can be quickly and efficiently carried out.

The invention discloses a position-free sensing method for a joint module based on rotating speed estimation and virtual Z correction. The method comprises the following steps: firstly, acquiring three-phase current of a permanent magnet motor for a joint module, and acquiring d-axis estimated current of a current period based on a d-axis current model in combination with a state quantity of the permanent magnet motor in a previous control period; based on the d-axis estimated current, constructing a rotating speed estimator taking the d-axis estimated current error as a sliding mode surface to obtain the estimated rotating speed of the motor rotor; integrating the estimated rotating speed, and combining with the initial position of the rotor to obtain the estimated position of the motor rotor in the current period; at the same time, at the zero crossing point of the stator phase current, the estimation position is forcibly corrected to a predetermined electrical angle corresponding to the zero crossing point so as to eliminate the integral error. The invention aims to directly estimate the rotating speed without depending on any intermediate signal, and simulate the correction mechanism of a mechanical sensor to eliminate the estimation error, thereby realizing high-performance noise-free full-speed-domain position-free sensing control.

A method of generating a timing control signal for controlling the timing of a change of a transformer tap of a transformer is provided. The transformer includes an on-load tap changer including plural respective transformer taps. The method includes monitoring a voltage on a primary side and / or on a secondary side of the transformer to obtain a monitoring signal and deriving, from the monitoring signal, an intermediate signal that is indicative of at least one zero crossing of a tap voltage at the transformer tap. Deriving the intermediate signal includes estimating, based on the monitoring signal, a phase of the monitored voltage to obtain a phase signal and applying to the phase signal a phase correction for a phase shift between the monitoring signal or a signal derived therefrom and the tap voltage at the transformer tap. The timing control signal is derived from the intermediate signal.

The invention relates to the technical field of magnetic shielding, and discloses a self-adaptive active adjustment type magnetic shielding device demagnetization circuit and device, and a control acquisition system, which are used for comparing a residual magnetism state with a preset expected value and generating a control instruction; the energy output identification system is used for outputting an alternating current degaussing signal according to the control instruction to perform degaussing, outputting an excitation pulse signal to perform residual magnetism detection, identifying a zero crossing point of the alternating current degaussing signal and realizing mode switching of degaussing and residual magnetism detection; and the magnetic shielding device is used for demagnetizing under the action of the alternating current demagnetizing signal and feeding back the residual magnetism state of the preset feature point under the action of the excitation pulse signal. The demagnetization is interrupted at the preset feature points in the demagnetization process, the real-time residual magnetism state is collected, and the demagnetization parameter at the next moment is adjusted after the real-time residual magnetism state is compared with the preset residual magnetism expected value, so that the problem of low efficiency due to the fact that the demagnetization parameter needs to be reset after the process is finished is solved, and the demagnetization efficiency and accuracy are greatly improved.

The invention relates to a relay pull-in self-learning method and circuit, and the method comprises the steps: collecting a front-end voltage value connected to the front end of a relay conduction path and a rear-end voltage value connected to the rear end of the relay conduction path, so as to calculate and generate corresponding voltage change information, judging whether the voltage change information meets a pull-in condition for determining that the relay is pulled in or not; if the pull-in condition is met, the time offset of the current actual pull-in moment of the relay relative to the alternating current zero crossing point is calculated according to the voltage change information; according to the time offset, the next actuation control signal sending moment of the relay is corrected in advance, so that the time difference between the next actual actuation moment of the relay and the alternating current zero crossing point meets the set offset threshold condition, and the actuation state of the relay is sensed in real time; therefore, the relay is closed at the moment closer to the alternating current zero crossing point, the impact current is effectively reduced, and the service life of the relay is prolonged.

A switching modulation circuit generates a first control signal with a duty ratio. A delay circuit delays the first control signal to generate a second control signal. A zero crossing detector detects whether an output current of a DC / DC converter is smaller than a threshold in a rectification interval, and generates a third control signal. A monitoring circuit detects a reverse-flow possibility of the output current, and generates a fourth control signal. A delay time of the delay circuit is set shorter than the delay time of the zero crossing detector. When the reverse-flow possibility does not exist, and the third control signal has transitioned to indicate that the output current is smaller than the threshold, a driver circuit turns off both first and second switching elements. When the reverse-flow possibility exists, and the second control signal has transitioned from an ON state to an OFF state, the driver circuit turns off both the first and second switching elements.

The invention discloses a root mean square value RMS detection method and system, and belongs to the technical field of measurement and control. Wherein a to-be-detected voltage signal is preprocessed by the filter amplification circuit, a square wave signal synchronous with a sine wave zero crossing point is generated through the zero crossing comparison circuit, a signal period boundary is identified, and an integral number of complete and continuous signal periods are extracted in real time through the period detection module; the cycle information identified by the cycle detection module is transmitted to the data storage and processing module, meanwhile, the sampling signal of the high-speed ADC module is transmitted to the data storage and processing module, and sine wave data sampled by the high-speed ADC module is subjected to point-by-point square operation; the square values in a complete period are accumulated and summed, and an original sampling sequence is not stored; fIR digital filtering is carried out on the RMS values of continuous C periods through a digital filtering module; and the dynamic response performance of the system under different frequency bands is remarkably enhanced while the measurement precision is improved.

The invention provides a receiving waveform position judging method of an ultrasonic flow metering device, and aims to improve the reliability of flight time measurement and reduce flow metering errors. According to the method, head wave and tail wave detection is achieved through the variable threshold comparator, the threshold is dynamically adjusted to adapt to different detection stages, and it is ensured that echo signals are accurately recognized. Through combination of zero crossing point flight time measurement and pulse width difference comparison, the method can determine the position of a tail wave, forwards presumes the position of an echo waveform, and judges the accuracy of a zero crossing point. In addition, the measurement accuracy is further improved by adjusting the phase of the transmitted ultrasonic signal to enhance the tail wave characteristic. The method is suitable for the field of flow measurement of water meters, heat meters, gas meters and the like, and metering errors caused by signal fluctuation or interference are effectively reduced.

The invention provides an electrical fireproof current-limiting protection system with normalized rated current amplitude, and relates to the technical field of electrical safety. The system converts the output voltage of a current sensor under different rated currents into a standard sinusoidal signal through hardware real-time rated current amplitude self-adaptive normalization processing; the system is not changed depending on the rated current; compensating the time delay of the instantaneous current and the main loop by using the difference value between the instantaneous current zero-crossing point and the main loop voltage zero-crossing point; and the instantaneous current values at different moments are directly compared with the corresponding short circuit threshold function values to realize short circuit fault identification, and the effective current values are directly compared with the overload threshold function values to judge overload faults. Through the design, rapid and accurate short circuit and overload protection can be realized, the risk of electrical fire is effectively reduced, and the reliability and efficiency of electrical safety protection are improved. The invention aims to solve the problems of poor universality, easy misjudgment and long response time of the existing electrical fireproof protection device for different rated currents.

The invention discloses a Loran-C system ground wave propagation ASF statistical property prediction method and related equipment, and the method comprises the steps: firstly obtaining the mean value and standard deviation of the electric field intensity in a random stratum-atmosphere waveguide environment based on a PCE-FDTD method, and on this basis, further positioning the position of a forward zero crossing point in a specific carrier period of a mean value time domain signal; therefore, the mean value of the ground wave propagation ASF of the Loran-C system is accurately calculated. Then, a linear approximation method is introduced, two sampling moments are selected at adjacent positions of mean value signals in the same period, and the propagation standard deviation of the ground wave propagation ASF signals of the Loran-C system on the flat terrain is rapidly obtained; finally, according to the method, the ASF mean value and the standard deviation of the Loran-C signal under the random medium background can be successfully obtained only through single simulation, and the solving efficiency is remarkably improved. The research provides a valuable insight for improving the accuracy of a PNT system and enhancing the stability and reliability of a communication system.

The invention relates to a two-way current smooth switching system and method without crossover distortion and a double-quadrant power supply, and the system comprises a signal setting unit, a dynamic bias ClassAB push-pull output unit, a feedback sampling unit and a control processing unit. According to the dynamic bias ClassAB push-pull output unit, static micro-conduction bias is provided for N-type and P-type power tubes in a push-pull output subunit through an internal bias subunit, and closed-loop control is combined, so that continuous and smooth transition can be realized when system output current is switched at a zero crossing point in the positive and negative directions, and the system stability is improved. And the problems of crossover distortion and switching dead zone existing in the traditional bidirectional power supply are thoroughly eliminated. According to the invention, high-efficiency, high-speed and distortionless bidirectional current output is realized, the system structure is simplified, and the system can be widely applied to the fields of high-precision test power supplies, battery simulators, servo drivers and the like.

The invention discloses a conductive slurry production control method and system based on multi-parameter cooperative control, and relates to the field of conductive slurry production, and the method comprises the steps: obtaining rheological characteristic data; according to the rheological characteristic data, a zero crossing point time difference between the excitation signal and the response signal is extracted, and a rheological phase angle is calculated; whether the rheological phase angle is located in a preset optimal dissipation interval or not is judged; if yes, the intrinsic relaxation time of the slurry microstructure is determined, and compensation frequency is generated according to the intrinsic relaxation time; the compensation frequency is used as a perturbation signal to be superposed to a driving voltage waveform of a driving motor, so that the stirring blades generate high-frequency vibration; and acquiring the deviation direction of the rheological phase angle, and dynamically adjusting the speed ratio of the revolution speed of the revolution shaft to the rotation speed of the rotation shaft under the condition of keeping the total power unchanged, so as to lock the rheological phase angle in the optimal dissipation interval. According to the invention, the yield and reliability of the electronic product can be effectively guaranteed.