291 results about "Total current" patented technology

The invention relates to the technical field of converter power averaging and circulating current suppression, in particular to a power averaging and circulating current suppression method for parallel operation of a plurality of grid-forming type energy storage converters, which averages power through communication interaction and generates frequency and voltage compensation quantity by adopting a first regulator and a second regulator to realize accurate power averaging; meanwhile, the total current is measured locally, and virtual impedance feedforward control is adopted, so that rapid suppression of the high-frequency circulating current is realized. According to the invention, high-precision active power and reactive power equalization is realized, the capacity utilization rate is improved, high-frequency circulating current is effectively suppressed, loss and thermal stress are reduced, dynamic performance and system reliability are considered, a cooperative control architecture with complementary advantages is formed, adaptability to complex working conditions and system stability are enhanced, and engineering applicability is improved.

The invention relates to a coordination method and device for harmonic suppression and reactive power compensation in a power distribution network. The method comprises the steps of obtaining power grid operation parameter information of a power distribution network; according to the power grid operation parameter information, the total current harmonic distortion rate, the power factor and each harmonic current information of the power distribution network are detected; detecting to-be-optimized parameters of the power distribution network according to the total current harmonic distortion rate, the power factor and the current information of each harmonic, the to-be-optimized parameters including at least one of each harmonic and reactive power; and according to the to-be-optimized parameters, suppressing each harmonic in the power distribution network and compensating reactive power in the power distribution network. The method can accurately perform cooperative control on harmonic suppression and reactive power compensation in the power distribution network.

The invention discloses a wide temperature range compensation method for resistive current of a lightning arrester, which belongs to the technical field of online monitoring of power equipment, and comprises the following steps: acquiring waveform data under a reference low-temperature working condition, and establishing an initial capacitive harmonic base; acquiring working condition data at any temperature in real time, performing harmonic decomposition, and analyzing to generate a nonlinear distortion feature vector; dynamically correcting the initial base by using the feature vector, and carrying out subtraction operation on the total current harmonic wave to obtain a final resistive current harmonic wave vector; and reconstructing an instantaneous resistive current waveform through inverse transformation and calculating a characteristic value. According to the technical scheme, the initial capacitive harmonic wave base is established, the nonlinear distortion feature vector is generated based on the harmonic distortion of the real-time working condition quantification temperature and valve plate nonlinear coupling, and dynamic feedback correction is conducted on the base, so that the real resistive current waveform in the wide temperature range can be accurately separated and reconstructed, and the accuracy of the real resistive current waveform in the wide temperature range is improved. And the accuracy and reliability of lightning arrester state evaluation are improved.

The invention belongs to the field of electrical variable measurement, and particularly relates to a single battery equalization management method for a lithium battery BMS (Battery Management System) protection board, which comprises the following steps of: acquiring voltage, temperature, total current and cycle index of each single battery in real time; based on a second-order equivalent circuit model and an extended Kalman filtering algorithm, multi-source information is fused, and the health state and the charge state are estimated with high precision; constructing a dynamic equilibrium trigger threshold fusing the charge state standard deviation, the range and the health state attenuation factor; a bidirectional flyback or multi-winding transformer active equalization strategy is selected according to the inconsistent distribution characteristics and the temperature field, and equalization current is accurately controlled through pulse width modulation; and continuously monitoring the efficiency, the temperature rise rate and the convergence in the equalization process, and dynamically optimizing the equalization parameters by using the fuzzy logic controller until the inconsistency reaches the standard. According to the technical scheme, accurate, self-adaptive, high-efficiency and safe single battery equalization management can be realized, the service life of the battery pack is effectively prolonged, and the operation reliability of the system is improved.

The invention belongs to the technical field of quality detection, and discloses an electrical automation quality detection method and system. The method comprises the steps of collecting original voltage and current signals of a PCC point of a power grid and performing FFT to obtain a background harmonic frequency set and a background harmonic amplitude set; generating an initial frequency grid based on a preset target frequency band, and generating a sparse frequency grid in combination with the background harmonic waves; calculating the estimated signal-to-noise ratio of each candidate frequency, performing ascending sorting to obtain an injection sequence, injecting sinusoidal signals, collecting PCC point voltage response and total current, and calculating a frequency impedance data pair; performing rational function fitting based on the frequency impedance data to obtain a broadband impedance curve; analyzing the curve, extracting quality characteristic parameters, and performing quality judgment according to the parameters; according to the method, the technical problem that the grid-connected stability quality of a single new energy converter cannot be quickly and automatically qualified in a production line offline detection scene in the prior art is effectively solved.

The invention discloses a battery monomer self-adaptive equalization method in a new energy automobile charging process, and aims to solve the problems of lagging, stiffness and poor coordination with a charging process of an existing equalization technology. The method comprises the following steps: collecting total voltage and total current of a battery pack and voltage and temperature of each monomer in real time; calculating a single voltage dispersion index and comparing the single voltage dispersion index with a threshold value to judge an equalization starting opportunity; dynamically calculating an adaptive equalization threshold based on the average state of charge, the average temperature and the aging degree of the battery pack; classifying each monomer according to the threshold value, and constructing a balanced target recognition matrix; and finally, in combination with the current charging stage, executing a layered equalization decision, and controlling the charging equipment and the active equalization circuit to work cooperatively. According to the method, deep coordination of equalization and charging is realized, the charging speed, the energy utilization rate and the charging saturation of the battery pack are remarkably improved through a dynamic threshold value and a hierarchical control strategy, and the overall service life of the battery pack is effectively prolonged.

A method for protecting a battery of an electronic device including a plurality of batteries, includes: measuring a total current (Itotal) value output from a charging module while the plurality of batteries are charged via the charging module; detecting a first current (I1) value output to a first battery via a current limiter; calculating a difference between the total current (Itotal) value and the first current (I1) value to estimate a second current (I2) value transferred to a second battery without passing through any current limiter, where the first battery and the second battery are included in the plurality of batteries; and controlling, based on the estimated second current (I2) value, a current of the second battery, which has the second current (I2) value, by controlling opening / closing of a switching module included in a protection circuit module of the second battery.

The invention provides an online detection system and method for electrochemical alternating-current impedance of a fuel cell, and aims to solve the problems of limited measurement frequency range and insufficient control precision caused by bandwidth limitation of a controller in the existing EIS online detection technology, and the online detection system comprises a fuel cell and a power supply system of a DC-DC converter, the disturbance signal generation module generates a sine disturbance current signal; the feedforward and feedback control module takes the total current reference signal as a control target, and calculates to obtain a final adjustment duty ratio for driving the DC-DC converter; when the DC-DC converter is driven by the final adjustment duty ratio, a data acquisition module synchronously acquires an input voltage and an input current which are input into the DC-DC converter as a response voltage signal and a response current signal; and the impedance demodulation module is used for demodulating and calculating the electrochemical alternating current impedance of the fuel cell based on the frequency of the response voltage signal, the response current signal and the sine disturbance current signal.

The invention discloses a programmable low-temperature-drift under-voltage locking circuit, and the circuit comprises a reference current generation module which is used for outputting an initial reference current, and the input end of the reference current generation module is connected with a first reference voltage; the zero-temperature-drift current source array is used for generating reference current according to the initial reference current and the second reference voltage and mirroring the reference current to a plurality of parallel branches; the trimming module is used for adjusting the total current of the parallel branches by using a programmable resistor and a capacitor; the sampling module is used for sampling the total current and the power supply voltage of the parallel branches output by the trimming module; and the comparison output module is used for comparing the power supply voltage with a sampling voltage generated according to the programmable resistor and the total current of the parallel branches, and outputting a pair of differential signals. Through the reference current generation module, the zero-temperature-drift current source array, the trimming module, the sampling network and the voltage comparator, the problems that in an existing resistance voltage division type undervoltage locking scheme, a threshold value is fixed and cannot be adjusted, and the scheme is sensitive to temperature changes are solved.

A switch shut-off device is applied to a power supply system equipped with a first power source and a second power source connected via an electrical pathway, and a plurality of switches provided in the electrical pathway and connected in series with each other. The switch shut-off device includes a calculation unit configured to acquire an energization current flowing through each of a pair of switches that are adjacent to each other in the electrical pathway, among the plurality of switches, and to calculate a total current that is a sum of the energization currents flowing to an intermediate point between the pair of switches, and a shut-off unit configured to shut off the pair of switches when the total current exceeds a threshold current.

The invention belongs to the technical field of electronic information, and relates to an online low-voltage load monitoring and abnormal tripping positioning method and a related device. According to the method, electrical parameters of all monitoring points are collected in real time, key parameters are calculated after analog-to-digital conversion and filtering denoising, and the key parameters are compared with a set threshold value to judge whether the monitoring points are in an abnormal state or not; once an abnormal state is found, an early warning is generated and uploaded to a remote platform; and continuously monitoring the state of the main switch or the total current at the same time, and when tripping occurs, backtracking an abnormal record within a preset time period before tripping, and positioning the last or the most serious abnormal monitoring point as an abnormal source. The system comprises a data acquisition module, an analog-to-digital conversion module, a preprocessing module, a calculation module, a judgment module, an early warning module, a trip monitoring module and a positioning module. According to the invention, early warning before a fault and rapid positioning after tripping are realized, and the intelligent level, the operation and maintenance efficiency and the power supply reliability of the power distribution network are improved.

The invention provides a distributed photovoltaic grid-connected converter low-voltage ride-through control method based on sum-difference coordinate transformation, and solves the problems of insufficient synchronism, poor stability, insufficient reactive power support potential excavation and the like existing in collaborative response under power grid voltage drop during distributed photovoltaic grid connection. According to the method, impedance modeling and equivalent symmetry transformation are carried out on the distributed photovoltaic inverter, and a coupling multi-dimensional matrix equation is established; an original coupling system is decoupled into a sum current channel and a plurality of difference current channels, the control complexity is simplified, and an open-loop output impedance expression and a closed-loop output impedance expression are deduced; secondly, formulating a refined active / reactive current collaborative distribution strategy for different voltage drop depths, dynamically calculating the minimum reactive current during voltage drop, preferentially meeting the national standard, and maximizing active output or balancing loss under the limit of rated current; and finally, through sum-difference coordinate transformation, the total current demand and distribution are efficiently decoupled and issued to a current loop controller of each inverter, so that rapid, synchronous and stable cooperative operation of multiple inverters is realized.

The invention relates to a power supply circuit with a monitoring function comprising a first current branch (2) with a first controllable section (20) and at least one load (21) arranged in series therewith, and a second current branch (3) with a second controllable section (30) and at least one load (31) arranged in series therewith. A controllable converter (4) is connected to the first and second current branches (2, 3) to supply a total current. A control circuit (5) with a control input, which is connected to the set input (10), wherein the control circuit (5) is coupled to the first controllable section (20) to adjust a current through the first current branch (2) depending on a provided first set signal.The second controllable branch (30) is coupled to the first current branch (2) and to the set input (10) in a dependent control loop, which is influenced by the current flowing in the first circuit (2) and the forward voltage of the two loads (21 and 31). It is configured to control a current through the second current branch (3) depending on an operating state through the first current branch (2) and a second set signal. Furthermore, a current-controlled monitoring circuit is provided, which is connected to a node between the respective current branch and the load connected in series with it. This circuit is configured to generate an error signal in response to a predefined deviation of one of the currents flowing into the current-controlled monitoring circuit, which reflects the state of the respective load.

The invention relates to the technical field of power electronic application, in particular to a negative-sequence voltage compensation control method of a network-forming STATCOM (Static Synchronous Compensator). Comprising the steps of bridge arm current reference instruction unit phasor calculation, reactive voltage control, bridge arm positive sequence and negative sequence reactive current instruction calculation, bridge arm current reference instruction amplitude limiting logic, zero sequence voltage injection control and modulation wave instruction calculation. According to the method, the negative-sequence current output by the networking STATCOM in the asymmetric transient fault is always inductive, the proportion coefficient of the amplitude of the negative-sequence current instruction can be adjusted according to the requirements of an engineering project, and the cost is reduced; by dynamically solving a quadratic equation of unary of a reactive current amplitude limiting coefficient, an active current instruction is not limited by amplitude, balance control of direct current voltage is preferentially ensured, the reactive current is reasonably limited in amplitude, a total current reference instruction value is always in a maximum design value range of short-time overcurrent, and the stability and the safety of the device are improved.

The invention discloses a method for supporting high-frequency AC / DC component acquisition in core grounding current monitoring, which belongs to the technical field of transformers and comprises the steps of system initialization and communication establishment, continuous sample acquisition, period preprocessing and frequency spectrum and DC component calculation. The technical problem of accurately collecting and analyzing the high-frequency harmonic component and the direct-current component of the grounding current of the iron core at the same time is solved, the dual-channel sampling and digital signal processing technology is combined, on the basis of calculating the total current and the power frequency component, multi-dimensional monitoring and intelligent analysis of the running state of the transformer are achieved, and the fault diagnosis accuracy of the transformer is improved. According to the invention, various industrial scenes can be covered, missing detection of potential faults is avoided, and the fault early warning capability and the operation state judgment precision are improved.

The invention relates to a current stress optimization hybrid modulation strategy of a three-phase dual-active bridge converter, which gets rid of a traditional symmetric bridge phase shift modulation strategy, provides a modulation mode of simultaneously switching on and off a b-phase switch tube and a c-phase switch tube in the three-phase dual-active bridge converter, and enables the phase a to be compared with the b-phase switch tube and the c-phase switch tube to have variable bridge internal shift. A modulation strategy of a three-phase dual active bridge converter similar to a DAB triple phase shift modulation mode is formed; meanwhile, mixed modulation is formed with single phase shift modulation of the three-phase dual-active bridge converter, total current stress serves as an optimization target, Pn is obtained through calculation of a PI controller, the voltage transformation ratio M at the moment is calculated, values of respective total current stress under the two kinds of modulation can be obtained, the total current stress under the two kinds of modulation is compared, and the optimal value of the total current stress under the three-phase dual-active bridge converter is obtained. And a modulation mode with the optimal real-time total current stress is selected, so that the total current stress of the converter is optimized under the same transmission power.

The invention provides a leakage current detection method, a power supply device and a storage medium, the leakage current detection method is applied to a scene that the power supply device is connected with at least one other measurement device besides a to-be-detected load device, and equivalent leakage impedance introduced by the at least one measurement device itself is quantified. In combination with the actual output voltage of the power supply device in the current scene working state, the leakage current value flowing through the measuring device is accurately calculated so as to compensate the current between the power supply device and the load device. Compared with the traditional scheme, the detection method actively measures and quantifies the current interference caused by the equivalent leakage impedance of the measurement equipment, and further compensates the leakage component in the total current measurement value supplied to the load by the power supply, thereby realizing the accurate reduction of the real current of the load, and improving the overall precision and reliability of the current measurement; meanwhile, the detection and compensation mechanism does not depend on complex hardware isolation and has the advantages of being low in implementation cost and high in adaptability.

The invention discloses a seamless range switching system and a seamless range switching method for instrument current measurement. The seamless range switching system comprises a digital-to-analog converter, an error amplifier, a first driving circuit, a first current measurement circuit, a clamping circuit, a second driving circuit, a second current measurement circuit, two analog-to-digital converters and a field programmable gate array. The first current measuring circuit converts 10 [mu] A to 30 mA low current into a first voltage signal to form a negative feedback closed loop. When the first voltage signal reaches a Zener breakdown threshold value, the clamping circuit outputs a trigger signal to start the second driving circuit, so that the two driving circuits jointly provide a total current of 30mA to 500mA for the load; the two analog-to-digital converters perform synchronous sampling, and the field programmable gate array selects digital signal output which is in a linear measurement range and has an error not exceeding + / -0.05% of a full scale. No mechanical switch exists in the switching process, the current is uninterrupted, and wide-range high-precision continuous measurement is achieved.

The application discloses a superconducting synchronous phase modifier excitation power supply device, which comprises a three-phase rectifying device, an adjusting module, a protection module and a digital control module, wherein the three-phase rectifying device is used for providing a bus side DC voltage; the adjusting module is used for adjusting an excitation total current; the protection module is used for ensuring safe operation of the device; and the digital control module is used for realizing high-precision continuous adjustment of excitation winding voltage and current. The superconducting synchronous phase modifier excitation power supply device solves the problem of unbalanced reactive output of the superconducting synchronous phase modifier caused by large excitation current ripple, and improves the reliability of the superconducting synchronous phase modifier.

The invention discloses a temperature control method and device for a laser and a medium, and relates to the technical field of temperature control, and the method comprises the steps: obtaining the operation parameters of a pump source assembly in a laser system, and carrying out the data query and interpolation calculation through a predefined current heat mapping table based on the pump source current in the operation parameters, and generating a thermal load prediction value; based on the thermal load predicted value and according to the working mode of the laser, a refrigeration control signal is generated, and the refrigeration control signal is sent to an execution component of the refrigeration system so as to control at least one of the rotating speed of a compressor, the opening degree of an expansion valve and the rotating speed of a fan; and calculating a current fine tuning coefficient according to the difference between a target temperature value in the thermal load predicted value and an actual temperature value, performing overall current compensation according to the difference between a power set value in the thermal load predicted value and an actual power value, and outputting an independent current adjustment value and a total current adjustment value of each pump source assembly.

The disclosure relates to a method for mapping an input vector to an output vector by means of a matrix circuit which has memory cells arranged in a matrix in a plurality of rows and a plurality of columns and first, second and third lines, each memory cell having an adjustable memory state, is connected to the first line (22) of the corresponding row, is connected to the second and third lines of the corresponding column and is set up to generate an electrical current (I1, I2, I3) depending on the memory state and voltages applied to the first, second and third lines, is connected to the second and third lines of the corresponding column and is arranged to conduct an electric current (I1, I2, I3) into the third line (26) as a function of the memory state and voltages applied to the first, second and third lines, each memory cell having a semiconductor switching element (28) with a control terminal which is connected to the second line (24) of the corresponding column; wherein input voltages (U1, U2, U3) corresponding to components of the input vector are applied (110) to the first lines; wherein for each column: a ramp voltage (V1, V2, V3) is applied (120) to the second line assigned to the column, the level of which is increased with time (130); a total current is detected at the third line assigned to the column and a time period elapsed since a start time of the level increase of the corresponding ramp voltage is determined (150) until the magnitude of the total current reaches a certain current magnitude threshold (Ig) (140); and a component of the output vector corresponding to the column is determined (170) based on the elapsed time period (t1, t2, t3).

The application discloses a battery monomer adaptive equalization method in a new energy vehicle charging process, and aims to solve the problems of existing equalization technology lag, rigidity and poor synergy with the charging process. The method comprises the following steps: collecting the total voltage, total current, and each monomer voltage and temperature of the battery pack in real time; calculating the monomer voltage dispersion index and comparing it with the threshold value to determine the starting equalization opportunity; dynamically calculating the adaptive equalization threshold based on the average state of charge, average temperature and aging degree of the battery pack; classifying each monomer according to the threshold value, and constructing an equalization target identification matrix; finally, combining the current charging stage, executing hierarchical equalization decision, and controlling the cooperative work of the charging equipment and the active equalization circuit. The application realizes the deep synergy of equalization and charging, significantly improves the charging speed, energy utilization rate and battery pack charging saturation through the dynamic threshold and hierarchical control strategy, and effectively prolongs the overall life of the battery pack.

This invention proposes a simulation method and system for the current response of distribution networks based on multi-frequency coupling effects, belonging to the field of power system modeling and simulation technology. The method includes: obtaining the frequency domain admittance matrix of the distribution network; extracting the same-frequency admittance vector and coupled admittance vector; converting each admittance vector into a transfer function, and then converting the transfer function into a discrete state-space model; preprocessing the voltage input signal using dq transform to reconstruct components at specified frequencies; substituting the preprocessed voltage signal into the discrete state-space model to obtain the current response of each frequency component; solving for the optimal weighting coefficients using an adaptive weighting strategy, and linearly superimposing the current responses to obtain the real-time simulated total current response.

The invention relates to the technical field of engineering machinery, and provides a motor control method and system for engineering machinery, and the method comprises the steps: determining a total current allowable value of a DC side of a whole vehicle according to the fusing current of a battery fuse; calculating the total current budget of all walking motor controllers based on the total current allowable value and the real-time working current of the oil pump motor controller; and distributing a direct current side current limit value corresponding to each walking motor controller according to the total current budget, and issuing the direct current side current limit value to the corresponding walking motor controller, so that the walking motor controller controls the output torque according to the direct current side current limit value. According to the invention, when the total current is limited, the current demand of the oil pump motor is guaranteed preferentially, so that the continuity of core operation actions such as excavation and lifting is ensured, smooth intervention can be carried out before the total current is close to a safety threshold, fundamental protection jump from passive fusing to active prevention is realized, and the safety of the oil pump motor is ensured. And the operation safety and reliability of the whole vehicle under complex working conditions are improved.

Methods and electric circuit arrangements for protecting metallic components in an electrolytic medium from corrosion due to direct-current (DC) stray current (Is) from a power supply system. The DC stray current may be jointly registered as a total sum current across all active conductors together with the protective conductor of the power supply system by a DC total differential-current sensor. Alternatively, a combined DC differential-current sensor is switchable by a switching device, a differential current being registered across all active conductors or the DC stray current being registered as a total differential current across all active conductors and the protective conductor. Alternatively, a differential current may be registered across all active conductors by a DC current sensor at the protective conductor and the DC stray current computed by forming differences of the differential current registered by the differential-current transformer and of the protective conductor registered by the DC current sensor.

The invention discloses a multi-module parallel system, a current sharing control method thereof, control equipment and a storage medium, and relates to the technical field of electrical control, and the current sharing control method of the multi-module parallel system comprises the steps: obtaining a three-phase total current value of the multi-module parallel system and a circulation current value of each target module; each target module comprises N-1 modules in all N modules in a working state in the multi-module parallel system; according to the three-phase total current value and the circulating current value of each target module, generating a current-sharing modulation signal of each target module; and controlling each target module to operate based on the current sharing modulation signal of each target module. According to the invention, the current sharing control of the multi-module parallel system can be realized simply and conveniently at low cost.

The invention provides a mobility separation method and device for a core-shell structure junctionless transistor, and the method comprises the steps: obtaining a first relation curve of drain current-gate voltage and a second relation curve of gate channel capacitance-gate voltage, determining first gate voltage when a core layer in the core-shell structure junctionless transistor is in a flat band based on the second relation curve, and separating the mobility of the core-shell structure junctionless transistor from the first gate voltage. In the first relation curve, determining the drain current corresponding to the grid voltage as the first grid voltage as the first current in the core layer, and according to the first relation curve and the first current, determining the second current in the shell layer of the junction-free transistor with the core-shell structure. And according to the second current, the transconductance of the second current to the gate voltage, the gate voltage and the first gate voltage, determining the first mobility of the shell layer in the core-shell structure junctionless transistor. In short, the current in the single channel is separated from the total current, and then the mobility corresponding to the channel is determined based on the current in the single channel, so that accurate characterization of the mobility of each channel is realized.

A power distribution management system dynamically manages power from an inverter to ensure uninterrupted supply to critical devices, such as power tools, while selectively controlling power to interruptible devices, such as battery chargers, to maintain total current below a predefined threshold. The system includes a microcontroller, an analog-to-digital converter for precise current measurement, and a powerline communications module for real-time data exchange. Current transformers monitor power to each connected device, enabling the system to identify and disconnect lower-priority loads, such as battery chargers, during high-demand periods, while ensuring essential tools remain powered. The system automatically restores power to disconnected devices when load conditions allow, optimizing efficiency and preventing overloading. This intelligent power management approach is particularly suited for portable or hybrid power systems in industrial and field applications.

The invention belongs to the field of electric digital data processing, and discloses an intelligent power supply protection control method for a weak current cabinet, which comprises the following steps of: executing instantaneous power supply interruption and recovery operation with limited time length on multiple ports according to a determined sequence so as to carry out sequenced probe scanning, the time length being smaller than the power-down holding time length of a load power supply; the total current is monitored in parallel to identify abnormity, and when abnormity is identified, sequential scanning is interrupted and focusing probe scanning is triggered; according to the method, the controlled port switching action is combined with synchronous sampling of a single total current sensor, the problem of port-level discrete information acquisition depending on multiple physical sensors in the past is solved, and the time duration of the operation is dynamically determined according to environmental parameters before interruption recovery operation each time. The problem is converted into a time sequence data processing problem based on a single information source, and a real-time power consumption data set covering all ports is constructed under the condition that the hardware cost is not increased.

The invention relates to a method and system for detecting the vacuum degree of a vacuum arc-extinguishing chamber based on high-frequency discharge and spectral analysis, and the method comprises the steps: exciting the interior of the vacuum arc-extinguishing chamber to generate field emission current through a high-frequency electric field, and obtaining a high-frequency current peak value through the spectral analysis of the field emission current; the vacuum degree is determined according to a pre-constructed vacuum degree-high-frequency current peak value standard relation curve, a high-frequency power source is connected to a vacuum arc extinguish chamber, the output voltage of the high-frequency power source is gradually increased until a vacuum gap breaks down, the voltage waveform in the process is recorded, and the total current of a loop is calculated; calculating a capacitive current component by combining the equivalent capacitance of the loop; and selecting a stable current section between two dielectric breakdown events in the total current, intercepting a current peak signal in the section, and subtracting the capacitive current component from the total current corresponding to the peak signal to obtain the field emission current. Compared with the prior art, the method has the advantages of high sensitivity, simplicity and convenience in operation, accurate result and the like.