407 results about "Pulse waveform" patented technology

The invention relates to the technical field of intelligent operation and maintenance of power equipment, in particular to a cable system full life cycle health management method based on digital twinning, which comprises the following steps: step 1, constructing a cable digital twinning body fusing electric-thermal-mechanical-chemical multi-physical fields; 2, dynamically fusing multi-source monitoring data, and collecting a cable skin continuous temperature sequence, a partial discharge pulse waveform and soil environment parameters; 3, solving a coupling equation of conductivity-thermal conductivity-stress tensor-ion diffusivity through iteration to realize multi-physical field linkage simulation; 4, generating a self-adaptive maintenance decision, inputting the insulation aging factor into an LSTM predictor to output a residual life prediction value, and generating a maintenance work order when the residual life is lower than a threshold value; and 5, carrying out closed-loop correction on the model, and updating the insulation aging factor calculation model and the physical attributes of the three-dimensional grid according to actual maintenance data. The method improves the safety, reliability and operation and maintenance efficiency of the cable system, and has important industrial application prospects.

The invention relates to the technical field of computer systems based on specific calculation models, and discloses a blood oxygen change monitoring algorithm fused with dynamic Bayesian modeling, which comprises the following steps: quantizing signal uncertainty by calculating entropy of pulse waveform harmonic energy distribution; and on the basis of the entropy value, driving a dynamic Bayesian network to carry out confidence coefficient evaluation and weighting processing on the blood oxygen estimation model, and finally outputting a decision pair containing a blood oxygen estimation value and the confidence coefficient thereof. According to the method, the signal uncertainty is converted into a computable entropy index, so that the system can autonomously distinguish real physiological changes and measurement noise, the problem of misjudgment caused by motion interference in traditional blood oxygen monitoring is avoided, meanwhile, non-inductive personalized calibration is achieved by utilizing the continuous learning ability of the Bayesian network, and the accuracy of the system is improved. And the reliability and the practicability of the medical wearable equipment are remarkably improved.

The invention relates to the technical field of electronic packaging, in particular to a welding process applied to a double-mesa device. The technology comprises the following steps that firstly, a heat conduction model of a double-table-board device is built, a temperature field prediction system is built in combination with measured data, secondly, an asymmetric double-pulse-current welding strategy is adopted, differential pulse waveforms are loaded to an upper table board and a lower table board respectively, independent temperature control over all welding areas is achieved, a temperature difference closed-loop feedback mechanism is introduced in the process, and the temperature field prediction system is obtained. Pulse parameters are dynamically adjusted according to real-time temperature deviation, a stress prediction and weld penetration monitoring module is used for assistance, the welding spot forming quality and heat stress balanced release are ensured, a staged annealing type cooling mode is adopted after welding, and the structural stability is improved. The method can be widely applied to MEMS modules, SiC power devices and heterogeneous chip laminated packaging double-mesa structure devices, and has the advantages of being high in welding precision, high in reliability and wide in process adaptability.

The invention relates to the technical field of integrated circuit manufacturing, in particular to a precise electroplating control system and method for an electroplated layer of a double-layer circuit board, and the method comprises the steps: building a multi-physical field coupling simulation model, and simulating the internal current density and ion concentration distribution of a via hole; constructing a mapping relation between the current density and the side wall electroplating thickness based on a simulation result, and predicting the electroplating thickness; through thickness prediction feedback, a time sequence adjustable pulse current control strategy is designed, the pulse amplitude, the duty ratio and the on-off period are dynamically adjusted, and current distribution optimization is guided; the state of the electroplating process is sensed in combination with real-time monitoring and analysis of multi-source parameters of electrode potential, conductivity and fluid velocity; and based on the prediction model and the real-time parameters, adjusting the pulse waveform and the time sequence through closed-loop compensation. According to the method, the uniformity and controllability of the thickness of the electroplated layer on the side wall of the via hole can be remarkably improved.

The invention discloses an electricity utilization information acquisition device of an electric energy meter metering pulse simulation system, and relates to the technical field of monitoring analysis, and the method comprises the steps: carrying out the ripple disturbance simulation of an initial pulse characteristic data set, and generating an interference pulse waveform matrix; performing multi-source interference signal separation processing on the waveform matrix with the interference pulses, constructing a three-dimensional clock error compensation network, generating a clock synchronization calibration pulse set, and extracting dynamic characteristic parameters corresponding to the clock synchronization calibration pulse set; performing multi-modal data fusion processing on the dynamic characteristic parameters to form compressed pulse characteristic data; establishing a simulation load feature matching model, outputting a simulation load adaptation parameter group, and converting the simulation load adaptation parameter group into a wireless transmission data frame; and carrying out transmission protocol self-adaptive packaging on the wireless transmission data frame, dynamically adjusting a data packaging strategy based on a channel quality evaluation index, and executing remote power utilization information acquisition and transmission. The method has the effect of improving the power utilization information acquisition efficiency.

Systems, devices, and methods described herein relate to generation and delivery of pulsed waveforms, e.g., for therapy delivery in soft tissue ablation procedures. In some embodiments, a pulse generator is configured to generate a voltage pulse train including a plurality of biphasic pulses, each biphasic pulse of the plurality of biphasic pulses including a positive pulse, a negative pulse, and an inter-phase delay separating the positive pulse and the negative pulse. In some embodiments, successive biphasic pulses of the plurality of biphasic pulses can be separated by a pulse-to-pulse delay such that the plurality of biphasic pulses is separated by a plurality of pulse-to-pulse delays, and the plurality of pulse-to-pulse delays can include increasing or decreasing sequences of pulse-to-pulse delays.

The invention discloses a live detection method for insulation defects of high-voltage power equipment. The method comprises the following steps: firstly, synchronously arranging ultrahigh frequency sensors and acoustic emission sensors on a plurality of monitoring points on the surface of a gas insulated switchgear shell to form an array, and synchronously acquiring signals for filtering pretreatment; then, pulse events are extracted from the two types of signals respectively, and associated pulses in a time window are matched into matched pulse pairs representing the same discharge source; then, carrying out time-frequency transformation on the ultrahigh frequency and acoustic emission pulse waveform in each matched pulse pair, carrying out joint noise reduction by calculating a coherence coefficient between time-frequency distribution matrixes, and extracting a joint feature vector containing an energy ratio, a time parameter ratio and a frequency difference from the denoised time-frequency matrix; according to the invention, multi-source signals are fused, and high-sensitivity detection, high-precision positioning and high-accuracy identification of insulation defects are realized.

The invention relates to the technical field of electromagnetic measurement, and discloses a line partial discharge positioning method and system based on pulse signal analysis, and the method comprises the steps: carrying out the band-pass filtering of pulse signal data, and obtaining a preprocessing signal; constructing a waveform template library based on the historical partial discharge pulse waveform data; screening out a partial discharge pulse and an interference pulse in the preprocessed signal to obtain a pulse matching result of the preprocessed signal; determining time difference data of the preprocessed signal according to time differences of pulses reaching different sensors in the pulse matching result; constructing an initial propagation velocity model according to the parameters and the environment data, performing iterative optimization on the initial propagation velocity model according to the time difference data, and determining an initial position of a partial discharge source in the line; correcting the initial propagation velocity model according to the initial position and the actual propagation path to obtain a target propagation model, and determining position coordinates of a partial discharge source in the target line according to the target propagation model; according to the invention, the accuracy of line partial discharge positioning can be improved.

The invention relates to the technical field of CLYC neutron-gamma rays, and provides a CLYC neutron-gamma ray screening detection method and device based on deep learning, and the method comprises the steps: carrying out the preprocessing of an original pulse waveform outputted by a CLYC detector, and obtaining clean standard waveform data; constructing a one-dimensional convolutional neural network model, respectively capturing the features of the waveform at different time scales, and identifying the most discriminative feature region in the waveform through an attention mechanism; performing adaptive adjustment on the original hyper-parameter of the one-dimensional convolutional neural network model to obtain an optimized hyper-parameter; establishing a direct mapping relation from an original pulse waveform to a neutron-gamma particle type to obtain a trained model; and carrying out compression optimization processing on the model, and deploying the model to an embedded platform to carry out neutron-gamma ray discrimination. According to the method, automatic extraction of deep discrimination features of the CLYC pulse waveform and accurate identification of key feature areas are realized, and the discrimination accuracy and noise interference resistance of neutron-gamma rays are improved.

The invention provides a signal processing method and system for a long-distance follow-up laser seeker, and belongs to the technical field of signal processing. Target surface center coordinates, a light spot image sequence and a synchronous echo pulse waveform sequence of the seeker are obtained; the speckle energy entropy and the centroid drift distance are obtained by calculating the information entropy and the centroid displacement of the target light spot image, and the pulse width parameter is extracted from the echo waveform. And constructing the three parameters into a laser feature vector, and inputting the laser feature vector into a pre-trained reflecting surface classification model so as to identify the surface material type of a laser irradiation point in real time. And determining a group of optimal follow-up control gain sets from the material gain mapping relation according to the surface material type, and dynamically reconstructing a follow-up control loop by using the optimal follow-up control gain sets. And the sight angle error of the light spot mass center and the target center is calculated, and the adjusted control loop is used for calculating the error to generate an accurate driving instruction signal, so that the tracking stability and the tracking precision of the target are improved.

The invention provides an electromagnetic interference motor-driven frequency converter control method and system and a medium, and relates to the field of motor control, and the method comprises the steps: collecting an electromagnetic interference signal in real time during the operation of a motor-driven frequency converter, generating interference spectrum data, carrying out the dynamic switching adjustment of the frequency converter, and generating an anti-interference modulation instruction; reconstructing a pulse waveform according to the anti-interference modulation instruction to carry out harmonic compensation, carrying out feedback verification based on the optimized driving signal, carrying out electromagnetic interference judgment according to a motor torque fluctuation value, and generating a judgment result; and triggering a parameter updating instruction based on the judgment result, and driving a frequency converter to perform adaptive control through the parameter updating instruction to generate a frequency conversion control result. The technical problem that a frequency converter control method in the prior art is limited in resistance to electromagnetic interference and affects the running stability of a motor is solved. The technical effects of improving the electromagnetic interference suppression capability and ensuring the stable and reliable operation of the motor are achieved.

The invention discloses a thoracic surgery postoperative complication assessment method and system based on multi-dimensional analysis, and relates to the technical field of thoracic surgery postoperative complication. Key sign signals such as heart rate fluctuation amplitude Cxv, respiratory rhythm drift coefficient Chx, pulse waveform disturbance degree Cmd and epidermal temperature change rate Cbt of a postoperative patient are continuously collected and denoised through a postoperative sign data acquisition module, and a structured sign data set TW is formed. By means of the method, tiny physiological fluctuation of a postoperative patient within 24 hours can be captured, early risk signals are prevented from being neglected, and the time sensitivity of complication recognition is improved from the source. A dynamic sliding window regression technology is introduced to carry out trend modeling on the sign data, so that a miniature instability section can be accurately extracted; through the improvement, the system can capture precursor signals of potential infection and bleeding earlier, and the possibility of early intervention is improved.

Systems, devices, and methods described herein relate to generation and delivery of pulsed waveforms, e.g., for therapy delivery in soft tissue ablation procedures. In some embodiments, a pulse generator is configured to generate a voltage pulse train including a plurality of biphasic pulses, each biphasic pulse of the plurality of biphasic pulses including a positive pulse, a negative pulse, and an inter-phase delay separating the positive pulse and the negative pulse. In some embodiments, successive biphasic pulses of the plurality of biphasic pulses can be separated by a pulse-to-pulse delay such that the plurality of biphasic pulses is separated by a plurality of pulse-to-pulse delays, and the plurality of pulse-to-pulse delays can include increasing or decreasing sequences of pulse-to-pulse delays.

The invention relates to the technical field of pulse acquisition, in particular to a high-speed ADC (Analog to Digital Converter) and FPGA (Field Programmable Gate Array) coordinated extremely-narrow pulse signal acquisition system, which comprises a phase identification monitoring module, a phase lock reference updating module, a sampling permission control module, a prohibition feedback identification module and a synchronous trigger adjustment module. According to the method, a beat tolerance judgment mechanism is introduced, hyper-bound phase deviation trend statistics and frequency vector extraction are combined, beat correction is carried out by utilizing a directional hopping cumulant and a period adjustment amount, a sampling permission judgment and keeping window alignment mechanism is introduced in a multi-frame period, and a two-way judgment means of a sampling starting trigger value is adopted, so that the beat tolerance of the multi-frame period is judged. And meanwhile, centralized extraction and frequency directivity statistics are carried out on the hopping direction in the sampling prohibition time sequence, the synchronous mismatch trend is distinguished, and the initial beat position is adjusted, so that the time domain characteristics of the narrow pulse waveform are kept continuous, the edge response is prevented from deviation, the trigger structure is stable and reliable, and the overall sampling judgment is more accurate and efficient.

The invention discloses a cradle head dynamic control method and device, and the method comprises the steps: obtaining a two-dimensional pixel coordinate of a target object on a display plane, converting the two-dimensional pixel coordinate into a physical space coordinate through a coordinate conversion algorithm, and obtaining the pixel offset of the target object relative to the center of a cradle head; based on the pixel offset and the pixel density parameter, performing angle calculation by using a trigonometric function calculation module to obtain rotation angle parameters required by the horizontal axis and the vertical axis of the holder; pWM control signal conversion is carried out on the rotation angle parameter, a corresponding number of pulse waveforms are generated through a stepping motor driving module, and a holder double-shaft motor is controlled to rotate; and based on the deviation value between the current position of the holder and the target angle, real-time error correction is performed by adopting a PID control algorithm, so that the holder tracks the target object in real time and keeps pointing to the position of the target object. Through the solid geometry correction technology, the problems of precise positioning and dynamic tracking of a traditional pan-tilt control system in a complex scene are solved, and the precision and stability of pan-tilt control are improved.

The invention provides a laser feedback adjusting method and system based on pulse waveform monitoring, and the system comprises a beam splitter and a detector which are disposed in a laser, the beam splitter splits the laser outputted by the laser into a main output light beam and a monitoring light beam, and the detector carries out the photoelectric conversion of the monitoring light beam to obtain a monitoring electric signal; the positive end of the comparator is connected with a monitoring electric signal, and the negative end of the comparator is connected with a periodically circulating reference voltage threshold signal so as to output a digital waveform signal containing pulse width modulation information; the FPGA processing unit calculates a waveform reconstruction parameter in real time according to the digital waveform signal based on a TDC digital time conversion technology, and generates a reconstructed waveform; the digital signal processor performs deviation analysis on the reconstructed waveform and the target waveform to obtain a deviation analysis result; and the FPGA processing unit generates a feedback control quantity according to the deviation analysis result so as to adjust the laser based on the feedback control quantity in the next feedback period to realize accurate tracking of the output waveform of the laser on the target waveform.

In a ranging device, a characteristic setting unit is configured to extract, from one or more pieces of received-light information representing changes with time in amount of received light acquired by the light receiving unit, at least one of a received-light amount range and a light reception time range of pulsed light other than emitted light from the light emitting unit, as a specified range. A received-light integration unit is configured to generate integrated received-light information by integrating the received-light information on a time axis with emission timings matched over a plurality of light receptions. A distance calculation unit is configured to exclude or identify distance noise formed of pulsed waveforms arising from pulsed light other than the emitted light, using the specified range extracted by the characteristic setting unit, and calculate a distance to the object reflecting the emitted light.

The invention discloses a partial discharge high-precision detection method and system, and particularly relates to the technical field of partial discharge detection. The method comprises the following steps: acquiring an original partial discharge pulse signal, and carrying out cross-correlation noise reduction processing in a strong electromagnetic interference environment to generate a space-time mixed signal after noise reduction; performing current path discrete point cloud reconstruction based on the space-time mixed signals, extracting discharge intensity distribution characteristics of the space-time mixed signals, and generating a spatial characteristic spectrogram; pulse waveform time-varying features of the space-time mixed signals in a time-frequency domain are extracted through wavelet scale spectrum decomposition, and a time sequence distribution diagram is generated; fusing the spatial characteristic spectrogram and the time sequence distribution map to construct a comprehensive spatial and temporal distribution map; based on the spatio-temporal characteristic parameters of the comprehensive spatio-temporal distribution atlas, the spatial position and the discharge starting time of the partial discharge source in the electrical equipment are traced, and the method is suitable for high-precision detection of partial discharge of the electrical equipment under complex working conditions.

The invention relates to a coronal bionic adhesion array electrodeposition method. Real-time current density, temperature and fluid flow rate sampling data in the electrodeposition process are collected in different regions of each key region of a coronal tail end bionic adhesion array electroforming core mold structure; a multi-field space coupling index is utilized to output parameter sets of local current, pulse waveform, micro-area stirring and the like with spatial resolution and dynamic response in real time, and closed-loop fine management of multi-channel power supply and micro-area stirring linkage control is realized.

The utility model belongs to the technical field of pulse power supplies, and particularly discloses a pulse power supply circuit, which comprises a power supply input module, a PWM (Pulse Width Modulation) signal input module, a feedback control module, a control chip and an output module, the power input module provides working power for the control chip and the whole circuit. The PWM signal input module is used for transmitting an external PWM signal to a signal input pin of the control chip; the feedback control module collects an electric signal in the circuit and transmits a processed feedback signal to the control chip; the control chip drives the output module to output a pulse power supply to provide electric energy for a load based on an input PWM signal and a feedback signal. According to the utility model, the feedback signal acquired by the feedback control module is compared with the reference voltage, the difference value is amplified, the control chip adjusts the duty ratio of the PWM signal according to the amplified error signal, the pulse waveform is effectively optimized, and the output stability and reliability of the pulse power supply are improved.

The invention discloses a multi-switch tube open-circuit fault-tolerant method and system for a dual three-phase permanent magnet motor system, and the method comprises the steps: calculating a current compensation value of a healthy phase through employing a Lagrange multiplier method according to the open-circuit fault conditions of different switch tubes on the premise that the magnetomotive force of a motor before and after a fault is not changed, and employing the minimum copper loss as a constraint condition; adding a corresponding phase current compensation value to each healthy phase so as to obtain a corresponding fault-tolerant reference current; coordinates of the sampled phase current and the fault-tolerant reference current under the fault condition are converted to a rotating coordinate system, and the reference voltage of each plane is solved through PI closed-loop control; and pulse waveforms generated by each plane reference voltage under a natural coordinate system act on the switch tube by using a carrier pulse width modulation strategy, so that fault-tolerant control of the open-circuit fault of the switch tube of the dual three-phase permanent magnet motor driving system is realized. According to the invention, fault-tolerant control under various switch tube open-circuit fault conditions is realized, and the reliability of the motor driving system under fault operation is improved.

The invention provides a rock-soil acoustic emission signal monitoring system and method, and belongs to the technical field of rock-soil monitoring, in the scheme, an acoustic emission probe is in contact with rock-soil to monitor fracture sound waves in real time and transmit the fracture sound waves to a signal processing module, and the signal processing module filters acoustic emission signals and then transmits the acoustic emission signals to an upper computer; the upper computer extracts rock-soil fracture acoustic emission signal features and displays the rock-soil fracture acoustic emission signal features; the upper computer circularly receives the data uploaded by the FPGA acquisition card and directly accesses the uploaded data through memory mapping; setting multiple threads for concurrently processing acoustic emission signal data, adopting a lock-free queue for communication among the threads, and triggering the queue by using semaphore; and after the thread queue reaches a triggering condition, storing the acoustic emission signal and displaying a pulse waveform. The method has the beneficial effects that the problems of poor real-time performance and high false alarm rate in the rock-soil fracture acoustic emission monitoring process are solved, and the situation of missed alarm due to hardware communication delay is avoided.

The invention discloses an accurate X-ray radiation dose measurement system based on artificial intelligence, which comprises the following steps: acquiring CT image data of a patient and pulse irradiation parameters of radiotherapy equipment through terminal equipment, and calculating a patient specific anatomical structure dynamic influence factor set, a pulse waveform time domain characteristic factor and a tissue interface scattering correction factor; all the parameters are substituted into a dose measurement formula to obtain an accurate X-ray radiation dose value; through a deep fusion image recognition technology (such as a high-resolution anatomical structure, tissue density gradient and heterogeneous region distribution provided by CT / MRI), a secondary particle scattering effect of a junction region of a tumor and a normal tissue can be accurately represented; and dynamic anatomical information (such as respiratory movement and organ displacement) in the image is combined to correct the time characteristic (such as dynamic change under an instantaneous high dose rate) of the pulse radiation field in real time, so that the dose calculation accuracy of a fast algorithm in a complex scene is remarkably improved.

The invention relates to the technical field of photoelectric tube detection, in particular to a photoelectric tube high-voltage excitation type solar blind ultraviolet discharge detection method and system, and the method comprises the steps: obtaining original voltage sequence data collected by a high-speed transimpedance sampling circuit in real time; positioning feature points of each suspected pulse according to the original voltage sequence data, and extracting pulse waveform features; obtaining a physical confidence factor of each suspected pulse according to the falling edge attenuation characteristics; calculating effective discharge energy flow in unit time based on the physical confidence factor; calculating a discharge stability coefficient according to a coupling relationship between the time correlation entropy and the effective discharge energy flow; according to the method, a scheme from microscopic physical judgment, waveform form deconstruction and time law analysis to multi-dimensional trend prediction is constructed, so that the contradiction between the detection sensitivity and the quantification precision is solved; and adaptive tracking monitoring of the partial discharge process is realized.

The invention provides a multifunctional integrated waveform design method based on a multi-sub-pulse structure, and belongs to the field of radar detection communication anti-interference integration. Specifically, an information transmission modulation method based on joint modulation of partial phase modulation in sub-pulses and waveform position arrangement modulation between sub-pulses is proposed, and the communication rate is remarkably improved; intermittent sampling forwarding interference is effectively suppressed by using the orthogonal characteristic of waveforms between sub-pulses. A signal processing method based on monopulse multifunctional integrated echoes is provided, and Doppler tolerance is enhanced; according to the invention, the integration of detection, communication and anti-interference functions is realized, the detection and communication requirements of a high-speed moving target are met, and the engineering application value is high.

The invention discloses a synaptic plastic mechanism bionic circuit based on a threshold symmetric memristor, and relates to the technical field of bionic circuits, the bionic circuit comprises a pre-synaptic neuron circuit, the threshold symmetric memristor and a post-synaptic neuron circuit; the bionic circuit is divided into an excitatory synaptic moldability mechanism circuit and an inhibitory synaptic moldability mechanism circuit according to a synaptic moldability mechanism; the design method of the circuit comprises the following steps: firstly, designing neuron waveforms before and after synapse, then traversing changes of memristive synapse conductance values at different time intervals to obtain a corresponding curve of the conductance changes and the time intervals, verifying the fitting degree of a biological synapse plastic mechanism curve and the curve, and if the fitting degree is low, determining that the biological synapse plastic mechanism curve is not matched with the curve. And if not, redesigning the pulse waveforms before and after synapse. The synaptic plasticity mechanism simulated by the bionic circuit provided by the invention and a biological synaptic STDP mechanism model have a small fitting error, the provided design method is higher in universality, circuit parameters can be adjusted according to different memristors, and different forms of biological synaptic plasticity mechanisms can be simulated.

The invention discloses a switch cabinet monitoring method and device based on the Internet of Things technology and a medium, and relates to the technical field of Internet of Things fusion, and the method comprises the steps: inputting a multi-modal time series data set into a multi-physics field coupling digital twin model, and generating a predictive instruction set; dynamically adjusting a discrimination probability threshold and aggressive degree parameters in the lightweight convolutional neural network based on the risk level quantized value in the predictive instruction set to obtain an adjusted lightweight convolutional neural network; performing pattern recognition on the partial discharge pulse waveform data by using the adjusted lightweight convolutional neural network to generate a fault early warning event identifier; by constructing a multi-modal time sequence data set, efficient fusion and time synchronization of multi-physical field information such as partial discharge, temperature and vibration of the switch cabinet are realized, data integrity and accuracy of state sensing are improved, and safety and stability of long-term operation of the switch cabinet are effectively guaranteed.

Blood flow information, including blood flow velocity information, is extracted from speckle information of a time series of structural optical coherence tomography (OCT) images. Flow information can be determined from high-frequency information of the OCT images, a speckle density of the OCT images, from a co-occurrence matrix applied to the OCT image, from a machine learning analysis of an input OCT image, or the like. A flow profile analogous to a pulse waveform is then generated as a time series of the extracted flow information.

A high-frequency power supply device includes a first power supply that outputs a high-frequency AC voltage having a first frequency, a second power supply that outputs a DC pulse voltage including one or more continuous pulse waveforms, a matching box that receives the high-frequency AC voltage, performs impedance matching such that impedance viewed from the first power supply becomes constant, and outputs the high-frequency AC voltage, a filter that receives the DC pulse voltage, filters the DC pulse voltage, and outputs the DC pulse voltage to a pulse-power input terminal of a load, and an IMD suppression circuit that includes a first inductor having predetermined inductance provided between the matching box and an AC-power input terminal of the load, receives the high-frequency AC voltage, allows the input high-frequency AC voltage to pass through the first inductor, and outputs the high-frequency AC voltage to the AC-power input terminal of the load.

Provided is a spot welding method capable of performing current control that makes a rising slope of waveform constant even in a case where pulse-shaped waveforms overlap with each other. The spot welding method includes, for a welding current L10: setting a target rise current value P for each predetermined PWM pulse when the welding current L10 increases toward a peak current range R1; and setting, as a first target current value A, a target rise current value P that is larger than and the closest to a rise start current value S in a case where an effective value L14 of the welding current reaches a set welding current L23 while the welding current is decreasing toward a bottom current PB.