18121 results about "High voltage" patented technology

The invention provides a device for generating shock waves. The device may comprise an elongated tube and a conductive sheath circumferentially mounted around the elongated tube. The device may further comprise first and second insulated wires extending along the outer surface of the elongated tube. A portion of the first insulated wire is removed to form a first inner electrode, which is adjacent to a first side edge of the conductive sheath. A portion of the second insulated wire is removed to form a second inner electrode, which is adjacent to a second side edge of the conductive sheath. Responsive to a high voltage being applied across the first inner electrode and the second inner electrode, a first shock wave is created across the first side edge and the first inner electrode, and a second shock wave is created across the second side edge and the second inner electrode.

A buffered fuel cell able to convert fuel such as hydrogen into electricity and concurrently store generated electric charge electrochemically in a low-impedance electrical buffer capable of delivering high currents to a variety of electrical loads without significant voltage sag. A charge transfer regulator controlling energy flow between an array of series-connected or series-parallel connected fuel cells and an electrical buffer limiting fuel cell current densities, controlling charging C-rates, and preventing buffer overcharging. An intelligent system for managing a buffered fuel cell by dynamically matching fuel cell stack voltage to an electrochemical buffer thereby expanding its usable humidity and temperature operating ranges, preventing buffer damage from excessive load currents or improper voltage operation, and actively regulating cell temperature and humidity. Electrical isolated fuel cell modules enabling stacked operation at high voltages, disabling and bypassing unused or redundant modules, and facilitating galvanically isolated electrical charging, voltage balancing, and system communication.

An energy storage apparatus can comprise a battery enclosed within a housing and an ultracapacitor directly electrically coupled with the battery via one or more high voltage lines. The ultracapacitor can form a single integrated unit with the battery within the housing. The ultracapacitor can have a voltage capacity at least as large as the battery. The ultracapacitor can provide energy to the battery via the one or more high voltage lines to charge the battery. The ultracapacitor can have a greater power density and a smaller energy density than the battery. The ultracapacitor can removably electrically couple with a 110V or 220V outlet to receive energy originating from a utility grid. The battery can receive energy from the ultracapacitor when a voltage of the battery is below a threshold and can resist receiving energy from the ultracapacitor when the voltage of the battery is above a threshold.

The invention relates to the technical field of circuit breakers, in particular to a circuit breaker fault diagnosis method and system for switching an alternating current filter in an extra-high voltage converter station, and the method comprises the following steps: S1, synchronously collecting multiple parameters: synchronously collecting vibration acceleration signals, opening and closing coil current waveforms, arc light intensity and environment temperature and humidity parameters; s2, time sequence feature extraction: performing time-frequency domain decomposition on the vibration acceleration signal to obtain a mechanical action time sequence spectrum; s3, operation mode classification: determining the operation mode of the circuit breaker; s4, three-dimensional fault matrix construction: generating a three-dimensional fault matrix including spatial distribution characteristics; s5, dynamic threshold analysis: generating a diagnosis threshold interval dynamically adjusted along with the environmental parameters; and S6, comprehensive diagnosis output: outputting a mechanical jam grade, a contact ablation degree and an insulation deterioration early warning signal. According to the invention, the mechanical, electromagnetic and insulation characteristics of the circuit breaker can be reflected more comprehensively, and reliable guarantee is provided for safe and stable operation of a high-voltage power grid.

The invention discloses a pre-twisted damper fatigue life prediction method for an extra-high voltage ground wire, and particularly relates to the technical field of power transmission line vibration prevention. Collecting multi-source vibration and environment data, and constructing a vibration characteristic time sequence; amplitude, frequency and strain energy are extracted based on the multi-frequency vibration response, and a multi-frequency collaborative vibration model is established; obtaining a damper structure and material parameters, establishing a finite element model, coupling the finite element model with a vibration model, and simulating local stress response; a Rainflow counting method and a Miner damage criterion are adopted to construct a fatigue damage factor distribution matrix; predicting the residual fatigue life of the damper based on the damage evolution trend, and evaluating the replacement opportunity; according to the method, accurate fatigue life prediction and optimal replacement strategy recommendation of the pre-twisted damper under complex working conditions can be realized, and the method has high precision, high adaptability and engineering practicability.

Systems and apparatus are provided for a high-power microwave sensor using an unmanned aerial vehicle. The unmanned aerial vehicle may include a central body, at least one electric motor, and a barometric pressure feedthrough. The central body may include a first enclosure housing a plurality of low voltage components, a voltage feedthrough connector, and a second enclosure housing a plurality of high voltage components. The low voltage components may include a first signal processing system, a first radio transceiver, a flight controller, a second signal processing system, a second radio transceiver, and a navigation system. The high voltage components may include a plurality of electronic speed controllers, a power distribution module, an input power interface, and a plurality of high power filters. The components of each enclosure may be segregated such that the high voltage components do not create electromagnetic interference with the low voltage components.

Systems and apparatus are provided for a high-power microwave sensor using an unmanned aerial vehicle. The unmanned aerial vehicle may include a central body, at least one electric motor, and a barometric pressure feedthrough. The central body may include a first enclosure housing a plurality of low voltage components, a voltage feedthrough connector, and a second enclosure housing a plurality of high voltage components. The low voltage components may include a first signal processing system, a first radio transceiver, a flight controller, a second signal processing system, a second radio transceiver, and a navigation system. The high voltage components may include a plurality of electronic speed controllers, a power distribution module, an input power interface, and a plurality of high power filters. The components of each enclosure may be segregated such that the high voltage components do not create electromagnetic interference with the low voltage components.

The embodiment of the invention relates to a lithium cobalt oxide positive electrode material with a composite phase as well as a preparation method and application of the lithium cobalt oxide positive electrode material. The chemical general formula of the lithium cobalt oxide positive electrode material with the composite phase is AXCo (1-y) M (1y) O2, wherein x is more than or equal to 0.5 and less than or equal to 1, y is more than or equal to 0 and less than or equal to 0.03, A is Li or Li and Na, and M1 is one or more of A1, Zr, Ni, Mn, Y, Nb, La, Fe, Cu, Cr, Ti, W, Mg, Mo or Yb; the composite phase of the lithium cobalt oxide positive electrode material comprises an O2 phase, a T2 phase and an O3 phase; wherein the sum of the molar ratios of the O2 phase and the T2 phase in the composite phase is greater than or equal to 90%, and the molar ratio of the O3 phase is less than or equal to 10%. By regulating and controlling the composite phase proportion of the lithium cobalt oxide positive electrode material, the rate capability, the structural stability under high voltage, the stability of a thermodynamic structure, the specific capacity, a discharge platform and other characteristics of the positive electrode material can be effectively improved, so that the lithium cobalt oxide positive electrode material with high energy density and high stability is realized.

The invention belongs to the technical field of thermal circuit model construction, and particularly relates to a high-voltage power cable intermediate connection thermal circuit fault modeling analysis method and device, and the method comprises the steps: building a high-voltage power cable intermediate connection thermal circuit fault circuit model through analyzing a cable intermediate connection temperature inversion principle; the method comprises the following steps: establishing a geometric model for multi-physics field analysis of the intermediate connection of the high-voltage power cable by utilizing Comsol finite element simulation software, setting material parameters of each component, and setting field domain parameters; an electromagnetic field module is added, boundary conditions of electromagnetic field analysis are set, and a cable intermediate connection electromagnetic field simulation model is obtained; adding a solid heat transfer module to obtain a solid temperature field simulation model; obtaining an electromagnetic-thermal coupling model, and solving to obtain the temperature, current and loss of the cable middle connection wire core and the outer surface in different insulation states. According to the method, the cable intermediate connection fault problem can be found and predicted, and the reliability and the safety of the power cable are improved.

The invention relates to the technical field of digital simulation, and discloses an emergency rescue method and system based on unmanned aerial vehicles and an urban three-dimensional platform, and the method comprises the steps: calling an emergency rescue region model through the urban three-dimensional platform, driving an unmanned aerial vehicle formation to go to an emergency region to obtain real-time region information, and employing a pre-trained accident condition image recognition algorithm to recognize an accident condition image; accident condition characteristics such as smoke and fire, fire fighting access blockage, emergency exit blockage, urban inland inundation, dangerous slopes, dangerous building detection, illegal building of building roofs, river channel floating object recognition and high-voltage electric tower inclination monitoring are identified, and the accident condition characteristics are substituted into the regional three-dimensional model to generate an accident simulation model. Real-time accident condition feedback is provided through the accident simulation model, rescue workers are assisted to make scientific rescue decisions, through comprehensive analysis and accurate simulation of an emergency rescue area, the detection efficiency of the unmanned aerial vehicle is improved, the timeliness and accuracy of rescue are enhanced, and the problem that in the prior art, the efficiency is low through manual collection of the current accident condition is solved.

The invention discloses a high-integration-level matrix type magnetic sensing chip structure and circuit and a manufacturing method thereof, and belongs to the technical field of semiconductor devices, the chip structure comprises a plurality of matrix elements, a switch matrix and a rear-end interface circuit, and each matrix element comprises a cross-shaped horizontal Hall element and a switch device; the switch matrix is composed of switch devices in matrix elements; the cross-shaped horizontal Hall element matrix is an N * M Hall matrix element formed by an integrated 1 * M Hall element matrix in each row; according to the invention, the structure and the circuit of the matrix type magnetic sensing chip which can be used for statically and dynamically measuring multi-dimensional magnetic field distribution in real time in severe environments such as high temperature, high pressure and high radiation are innovated and manufactured; dynamic and static measurement in a multi-dimensional magnetic field space can be achieved, error compensation is carried out through a circuit, it is ensured that the chip can stably work in the high-temperature, high-pressure and high-radiation environment, and it can be ensured that the chip has high linearity, sensitivity and accuracy.

The invention relates to the field of temperature monitoring, and discloses a high-voltage passive induction temperature monitoring system, which comprises a plurality of temperature sensors, the plurality of temperature sensors are arranged in different cabinets and channels in a machine room; a control unit; the control unit is used for sending a detection instruction to each temperature sensor and receiving a feedback temperature signal; the control unit generates a temperature change curve of each monitoring point according to the received temperature signals; the control unit constructs a three-dimensional temperature distribution model of the whole machine room based on the temperature change curve of each monitoring point, identifies a potential hot spot area based on the three-dimensional temperature distribution model and predicts the temperature change trend of the potential hot spot area; a refrigeration unit; the refrigeration unit is used for adjusting the temperature of the located area; the refrigeration unit is communicated with the control unit; wherein the control unit adjusts the power of each refrigeration unit based on the identified potential hot spot areas.

A system includes: an AC-DC converter; and a DC-DC converter, the DC-DC converter including: a first high voltage buck-boost converter having a secondary side connectable to a first high voltage battery; a second high voltage buck-boost converter having a secondary side connectable to a second high voltage battery; a first low voltage buck-boost converter having a secondary side connectable to a first low voltage battery; a second low voltage buck-boost converter having a secondary side connectable to a second low voltage battery; and one or more transformers having a primary side connected to the AC-DC converter and a secondary side connected to each of a primary side of the first high voltage buck-boost converter, a primary side of the second high voltage buck-boost converter, a primary side of the first low voltage buck-boost converter, and a primary side of the second low voltage buck-boost converter.

The invention discloses a vacuum circuit breaker state online monitoring method and system based on digital twinning, and relates to the field of intelligent operation and maintenance of high-voltage power equipment. According to the method, various sensors are arranged at key parts of the vacuum circuit breaker, breaking current, shielding case potential and vibration signals are collected in real time, and a digital twinborn model is constructed by combining multi-source data preprocessing, three-dimensional modeling, behavior rule definition and fault simulation analysis; and on-line identification and trend prediction of electrical wear, vacuum degree deterioration and mechanical abnormity are realized. The system has the functions of real-time monitoring, three-dimensional visualization, model self-learning and intelligent early warning, can be widely applied to intelligent monitoring and state evaluation of circuit breaker equipment in a power system, and remarkably improves the operation safety and operation and maintenance efficiency of the equipment.

The invention provides an electrolyte, an electrochemical device and an electronic device, the electrolyte comprises lithium bis (fluorosulfonyl) imide, a sulfur-containing compound and propyl propionate, based on the mass of the electrolyte, the mass percentage content of the lithium bis (fluorosulfonyl) imide is A%, the mass percentage content of the sulfur-containing compound is B%, the mass percentage content of the propyl propionate is D%, B / A is greater than or equal to 0.3 and less than or equal to 4, and D is greater than or equal to 30 and less than or equal to 40. Through the arrangement, the risk that the alternating current impedance of the electrochemical device is increased under high voltage is reduced, and the anti-falling performance and intermittent cycle performance of the electrochemical device are improved.

The invention relates to an extra-high voltage converter transformer OLTC fault diagnosis method fusing multi-feature information and RIME-CNN-BiLSTM-SAM, and belongs to the technical field of intelligent monitoring of power systems. The method comprises the following steps: firstly, constructing a vibration signal fault data set based on an OLTC mechanical fault simulation experiment; secondly, decomposing an OLTC vibration signal into a plurality of intrinsic mode components by adopting REMD, and preferably selecting components containing rich fault feature information based on a correlation coefficient; then, the multi-scale permutation entropy of IMFs is calculated, time / frequency statistical analysis and the multi-scale permutation entropy are combined, OLTC multi-dimensional vibration characteristic parameters are integrally and locally concerned, and principal component analysis is introduced to carry out characteristic fusion and dimension reduction of OLTC vibration information; and finally, optimizing the hyper-parameters of the CNN-BiLSTM-SAM fault diagnosis model by using the RIME, and realizing the construction of the converter transformer OLTC intelligent fault diagnosis model. The method has a remarkable effect in the aspect of extracting OLTC fault feature information, the fault type recognition rate is superior to that of an existing method, and the effectiveness of the method in converter transformer OLTC fault diagnosis is verified.

A refuse vehicle includes a cab, a refuse compartment, a chassis, a high voltage power distribution unit (HVPDU) including a battery, a plurality of cables and a manual service disconnect. The manual service disconnect is accessed via a through hole of a wheel well of the refuse vehicle. The refuse vehicle further includes a platform removably coupled to the chassis and the HVPDU and configured to enclose the high voltage power distribution unit.

The invention discloses a scene self-adaptive aging test method and system for an extra-high voltage MOS (Metal Oxide Semiconductor), and relates to the related technical field of MOS test, and the method comprises the steps: building a device aging test platform; performing test condition analysis on the application scene information of the target extra-high voltage MOS device; performing pretest adjustment on the target extra-high voltage MOS device, and determining an aging test update parameter table; performing aging test monitoring on the target extra-high voltage MOS device; and calling an extra-high voltage MOS aging adaptive evaluator to process and evaluate the device aging scene test data stream set to obtain a device scene aging performance test result. The technical problems that in the prior art, due to the fact that an MOS aging test lacks scene adaptability, the aging process of the MOS device in the actual application environment is difficult to accurately simulate, the test pertinence is insufficient, and the result accuracy is poor are solved, and the technical effect of improving the MOS device aging test pertinence and the result accuracy is achieved.

The invention discloses a high-temperature-resistant, high-voltage-resistant and anti-breakdown capacitor base film and a preparation method thereof. The high-temperature-resistant, high-voltage-resistant and anti-breakdown capacitor base film is prepared from the following raw materials in parts by weight: 100 parts of polypropylene; 17 to 36 parts of polyvinylidene fluoride; 3-12 parts of enhanced and improved talcum powder; 1-6.5 parts of modified barium titanate; 1-6 parts of a cross-linking agent; 2-10 parts of a compatilizer; and 0.05-2 parts of an initiator. The capacitor base film is high in mechanical strength, and has excellent high temperature resistance, thermo-oxidative aging resistance, high voltage resistance and anti-breakdown performance; the enhanced and improved talcum powder is constructed by taking expanded layer modified talc as a carrier and titanium dioxide-carbon dot composite particles as a loading component and grafting and coating the organic matter, so that the defects of the talcum powder can be overcome, and the improvement effect of the talcum powder on heat resistance, high-voltage resistance and breakdown resistance can be fully exerted; meanwhile, the system can be endowed with excellent thermo-oxidative aging resistance.

The invention relates to the technical field of image processing, in particular to a high-voltage electrical equipment surface defect identification method based on image processing. The method comprises the following steps: analyzing the gradient of pixel points in a to-be-analyzed image of a to-be-detected area on the surface of the high-voltage electrical equipment to obtain the weight of each pixel point; weighting the gray value of each pixel point in the to-be-analyzed image subjected to Laplacian filtering by using the weight of each pixel point of the to-be-analyzed image to obtain a first feature map; calculating a local standard deviation of each pixel point in the to-be-analyzed image so as to obtain a first parameter and a second parameter; constructing two Gaussian kernels based on the first parameter and the second parameter to filter the to-be-analyzed image to obtain a second feature map; fusing the first feature map and the second feature map of the to-be-analyzed image to obtain a defect saliency map of the to-be-analyzed image; and recognizing a surface defect area of the high-voltage electrical equipment based on the defect saliency map of each to-be-analyzed image. According to the invention, the accuracy of high-voltage electrical equipment surface defect identification can be improved.

A modular electric power take-off (E-PTO) system for a refuse vehicle includes a modular housing. The modular E-PTO also includes a motor, an inverter, a battery, and a hydraulic pump positioned within the modular housing. The modular housing is removably coupled with a front of a waste receptacle or a hopper of the waste receptacle of a refuse vehicle.

The invention provides a fault positioning method and system based on multi-mode acousto-optic electric signal collaborative diagnosis, and the method comprises the steps: firstly collecting an acoustic signal sequence, an optical signal sequence and an electric signal sequence during the operation of high-voltage electrical equipment, and then carrying out the cross-mode signal level correlation processing of a multi-mode signal, and generating a multi-mode signal correlation level chain; extracting a dynamic association feature set based on the multi-modal signal association hierarchical chain, inputting the dynamic association feature set into the fault feature evolution model to generate a fault feature identification sequence and a feature space diffusion trajectory, and finally determining a fault initial region and a fault influence boundary range of the equipment according to the fault feature identification sequence and the feature space diffusion trajectory. Therefore, the accuracy and reliability of fault positioning of the high-voltage electrical equipment can be effectively improved.

The invention discloses a high-voltage circuit breaker arcing monitoring system and method, and relates to the technical field of power equipment operation state detection, and the method comprises the following steps: S1, synchronously collecting arcing spectral signals and electromagnetic interference vector data under a unified time reference, and carrying out primary differential processing to generate stable base plane signals; s2, inputting the stable base plane signal into the interference identification model, generating a multi-dimensional spectrogram through time-frequency mapping, extracting an interference time sequence boundary, and outputting an interference weight matrix; the arcing monitoring method based on spectrum and electromagnetic signal synchronous acquisition is constructed, interference identification, signal purification, energy analysis and control instruction generation are fused, parameter self-optimization is realized through closed-loop feedback, the arcing identification accuracy and the arc quenching response efficiency are effectively improved, and the arcing monitoring method is suitable for large-scale popularization and application. And the operation safety and the intelligent level of the circuit breaker in a strong interference environment are enhanced.

The invention relates to the technical field of power grid state monitoring, in particular to an intelligent monitoring and early warning method and system for a high-voltage power grid, and the method comprises the steps: collecting the multi-dimensional parameter data of a power grid node, and obtaining the multi-dimensional parameter data of the power grid node based on the relative deviation of the data of each dimension in a local window and the mean value of the data of each dimension in combination with the correlation coefficient of the data of each dimension; calculating parameter fluctuation attention at a target moment so as to correct parameter data of each dimension; processing the data points through a clustering algorithm to obtain a plurality of clusters, and selecting the cluster center of the cluster with the most data points as a power stability index; and calculating the relative deviation between the data point and the index, and generating a state early warning coefficient so as to estimate and evaluate the abnormality of the power grid node region and generate an early warning signal. According to the method, parameter fluctuation is accurately quantified by fusing the deviation degree and correlation of the multi-dimensional data of the local window, and a foundation is built for monitoring and early warning.

The invention discloses a high-voltage circuit for an electric flame stove. The high-voltage circuit comprises a PFC circuit, a high-frequency conversion circuit, a boosting transformer, an energy coupling circuit and a voltage doubling circuit which are electrically connected in sequence. According to the EMI filter circuit, common-mode interference and differential-mode interference are filtered out, and pure alternating current input is provided for a back-end PFC circuit; two chips are adopted in the PFC circuit, so that the PFC circuit 300 finally realizes the consistency of the current waveform and the voltage phase; in the other embodiment of the invention, double chips are adopted, so that'fault linkage protection 'is realized; stable discharging of multiple groups of positive and negative electrodes is achieved through multiple groups of single energy coupling capacitors and independent voltage doubling rectifier bridges which are connected in parallel.

The invention discloses a high-voltage level conversion circuit with a symmetric pulse current structure, which belongs to the technical field of integrated circuits and comprises a level conversion module, a symmetric pulse current auxiliary module and a latch output module. According to the level conversion module, the defect that in the prior art, when the voltage of a power supply jumps rapidly, a circuit may be triggered by mistake is overcome, and the immunity of the circuit is improved. According to the symmetrical pulse current auxiliary module, the defect that transmission delays at the rising edge and the falling edge of an input signal are asymmetric in the prior art is overcome, so that the symmetrical pulse current auxiliary module keeps high transmission delay symmetry while ensuring a high transmission speed; and the problem of possible distortion of digital signal input and output in a high-speed circuit is effectively suppressed.

The invention provides a positive electrode material, a lithium ion battery and a preparation method, and relates to the technical field of battery materials. The positive electrode material comprises an inner core and a coating layer, the inner core is a ternary material matrix, the coating layer is a fluorine-doped lithium cobalt oxide material, the lithium cobalt oxide material contains Co < 2 + > and Co < 3 + >, and in the coating layer, the fluorine element and the Co < 2 + > are both distributed progressively from the surface to the center. The positive electrode material effectively improves the capacity fading problem under high voltage, and shows excellent circulation capability, high capacity and low impedance under high voltage.

The invention relates to the technical field of batteries, in particular to a lithium ion secondary battery. The lithium ion secondary battery comprises a negative plate and electrolyte, the negative plate comprises a negative current collector and a negative active layer located on at least one side surface of the negative current collector, the negative active layer comprises a first coating and a second coating which are arranged in the thickness direction of the negative plate, and the first coating is located between the negative current collector and the second coating; the second coating comprises first silicon carbon, and the sphericity degree of the first silicon carbon is 0.8-1; the silicon content of the first silicon carbon is 30%-60%; the average particle size of the first silicon carbon is R1, and R1 is more than 6 microns and less than or equal to 15 microns; the electrolyte comprises a fluorine-containing solvent and a nitrile compound, the fluorine-containing solvent comprises fluoroethylene carbonate and / or ethyl difluoroacetate, based on the total weight of the electrolyte, the content of the fluorine-containing solvent is w1, and w1 is larger than or equal to 30% and smaller than or equal to 70%; the content of the nitrile compound is w2, and 0.4% < = w2 < = 7%. The lithium ion secondary battery provided by the invention has good cycling stability and dynamic performance at high voltage and high temperature.

The invention provides a surface interface modified lithium-rich manganese-based positive electrode material and a lithium ion secondary battery. According to the invention, active oxygen substances such as O2, O2-, O-and oxygen polymer On-are absorbed and embedded into lattice gaps from the particle surface interface of the lithium-rich manganese-based positive electrode material under the driving of potential when the functional material is charged to a high voltage, and then the active oxygen is released when the functional material is discharged to a low potential, so that the active oxygen returns to the lithium-rich manganese-based positive electrode material again; and an active oxygen utilization reversible closed loop is formed. In the surface-interface modified lithium-rich manganese-based positive electrode material provided by the invention, the application of the surface functional material inhibits oxidation precipitation of lattice oxygen of the lithium-rich manganese-based positive electrode material in a high-voltage lithium removal state, and the positive electrode material can realize controllable oxygen reversible electrochemical deintercalation / intercalation at different potentials; and the cycling stability and the thermal stability of the material in a high-temperature and high-voltage environment are remarkably improved.

The invention relates to an enhanced gallium nitride high-mobility transistor and a preparation method thereof. The transistor sequentially comprises a substrate, a buffer layer, an i-GaN channel layer, an AlGaN barrier layer, a p-GaN layer and a gate dielectric layer from bottom to top, the source electrode and the drain electrode are respectively in ohmic contact with the two-dimensional electron gas, and the grid electrode and the p-GaN layer are in Schottky contact, so that the two-dimensional electron gas below the grid electrode is exhausted to realize normal closing; an electrode is arranged in a region between the grid electrode and the drain electrode, a thin-layer medium is arranged below the electrode, and the thin-layer medium and the electrode form an equivalent MIS grid structure; and the electrode is electrically connected with the source electrode. The switching time of the device is determined by the switching speed of the p-GaN HEMT composed of S-G1-D. Compared with a traditional Si MOS cascade structure, the device has the advantages of being fast in switching and free of reverse recovery charges. And meanwhile, the withstand voltage of the device is determined by a depletion mode MIS GaN HEMT consisting of S-G2-D, and the p-GaN grid does not bear high voltage, so that the device has the advantage of high reliability.