42 results about "Displacement current" patented technology

The invention relates to a method for calculating the power-on and power-off delay time performance of an electromagnetic valve, and the method comprises the following steps: obtaining the mass of a valve element of the electromagnetic valve, the spring stiffness and coil resistance data; establishing an electromagnetic valve equivalent circuit model, and listing a current equation; establishing an electromagnetic valve magnetic circuit mathematical model, and listing a magnetic field equation set; establishing an electromagnetic valve flow field mathematical model, and listing a flow field equation set; establishing a kinematic model of the electromagnetic valve, and listing a kinematic equation; using a finite element method to obtain a valve core electromagnetic force-displacement-current data table and a coil inductance-displacement-current data table; a finite element method is used for obtaining a valve element aerodynamic force-displacement data table; and obtaining the power-on and power-off delay time through data analysis processing and solving of the partial differential equation set. According to the method, prediction of the opening and closing delay response time of the electromagnetic valve is more accurate, visual adjustment in the simulation process is achieved, and the time for obtaining the response time of the electromagnetic valve and the test cost are greatly reduced while the preset precision requirement is met.

The invention discloses a turn-off delay time detection device and a turn-off delay time detection method for on-line junction temperature detection, and aims to solve the contradiction between high voltage tolerance and accurate detection of a low voltage part in a traditional detection method and realize reliable on-line detection of the junction temperature of a power switch device. Comprises: a displacement current extraction circuit detects a capacitor element current having a function relationship with voltages at two ends of a detected power switch device, and outputs an electric signal containing current information; the starting moment detection circuit receives a grid voltage signal and detects a starting moment according to the standard that the grid voltage drops to 90% of a high level, and the ending moment detection circuit receives a current information electric signal and detects an ending moment according to an experimental calibration threshold; the turn-off delay time extraction circuit generates a signal containing delay time based on the time information; the controller calculates the junction temperature according to the calibration relation between the delay time and the junction temperature. High-voltage impact is avoided through indirect current detection, all links are accurately matched, and the device is suitable for various circuit scenes and has low cost and high reliability.

This invention provides an air conditioner, relating to the field of electrical technology. The air conditioner reduces electromagnetic interference by modifying the transformer. The air conditioner includes: a substrate; the substrate includes an electromagnetic compatibility (EMC) module; the EMC module includes a transformer; the transformer includes: a magnetic core, a primary winding and a secondary winding sequentially wound around the magnetic core; the transformer further includes: a first shielding winding and / or a second shielding winding; the first shielding winding is located between the magnetic core and the primary winding, and the second shielding winding is located between the primary winding and the secondary winding; the windings of the first shielding winding and the primary winding are opposite; wherein the primary winding generates a first displacement current to the first shielding winding, the magnetic core generates a second displacement current to the first shielding winding (the two currents are in opposite directions), the primary winding generates a third displacement current to the second shielding winding, and the secondary winding generates a fourth displacement current to the second shielding winding (the two currents are in opposite directions). This invention is used to reduce electromagnetic interference.

The invention discloses a shielded cable electricity testing method based on ground loop impedance potential lifting, and relates to the technical field of measurement. The electroscope comprises an electricity testing step, an induction electrode on the cambered surface of the electroscope is used for obtaining induced electricity, a broadband direct sampling framework is formed on the physical level, and broadband direct sampling of millivolt-level power frequency displacement current characteristics is achieved. Based on a variational mode decomposition-Duffing oscillator fusion weak signal extraction algorithm, a variational mode decomposition algorithm is utilized to adaptively strip broadband noise and higher harmonics, a reconstructed signal is subjected to scale normalization and then introduced into a critical chaotic state Duffing oscillator algorithm, phase transition of a phase track from a chaotic attractor to a large-scale limit cycle is monitored, and a weak signal is extracted. A non-linear dynamic weak signal extraction algorithm is formed on the algorithm level, and weak power frequency features masked by strong noise are accurately recognized; a broadband direct acquisition framework and a weak signal extraction algorithm form a dual detection framework, and a quasi-induction electric signal is detected and judged in the live part verification process of the shielded cable.

The invention discloses an electric field response type self-energy-taking system based on harmonic voltage of a high-voltage direct-current transmission line. An electric field induction energy taking device collects the harmonic voltage of the high-voltage direct-current transmission line based on the Maxwell displacement current principle; the rectifier is arranged between the electric field induction energy taking device and the high-voltage direct-current power transmission line and is used for converting induction alternating current into induction direct current; and the energy storage capacitor stores the induced direct current. According to the energy taking system, a periodic alternating electric field caused by harmonic voltage in a high-voltage direct-current transmission line is induced, the harmonic voltage of the high-voltage transmission line is converted into alternating current on the basis of the Maxwell displacement current principle, and available energy is obtained in a non-contact mode. Electric energy is converted and stored through the rectifier bridge and the energy storage capacitor, rectification conversion and energy storage are achieved, and then stable power supply support is provided for loads such as various low-power-consumption sensors or monitoring equipment on a power transmission line.

This invention provides a method and system for three-dimensional high-frequency controllable source electromagnetic numerical simulation with dual-source excitation. The method constructs a single-source electromagnetic field grid model and a three-dimensional spatial domain total field equation, converting it into a quadratic field control equation by separating the primary and secondary fields. Fourier transform is used to transform the equations to the wavenumber domain, and shape function interpolation is performed iteratively to obtain the wavenumber domain numerical solution. A single-source forward excitation solution is obtained through inverse Fourier transform. A single-source reverse excitation solution is obtained by reversing the current direction. Finally, the forward and reverse solutions are vector-superimposed to obtain the dual-source excitation simulation result. This invention solves the technical problems of existing technologies, such as simulation distortion caused by neglecting displacement current in the 100kHz-10MHz frequency band, numerical calculation interference from field source singularities, and low spatial resolution of complex underground anomalies under single-source excitation. By simulating gradient field response characteristics through dual-source reverse superposition, the sensitivity and exploration resolution of underground target boundaries are significantly improved.

The invention discloses a non-contact voltage high-precision inversion optimization algorithm, and belongs to the technical field of distribution network voltage measurement, and the algorithm comprises the following steps: designing a non-contact voltage sensor probe of a double-coupling mechanism based on a displacement current method, obtaining the voltage of a to-be-measured line through measuring the value of displacement current, and obtaining the voltage of the to-be-measured line based on the voltage sensor probe. The method comprises the following steps: acquiring response voltage signals in different periods through an MOSFET gating measurement loop, establishing a voltage measurement model considering frequency deviation of a power system, and correcting phase angle deviation caused by frequency deviation and estimating voltage by adding a response equation and a Newton iteration algorithm; the method can optimize the performance of the sensor probe, and has the advantages of prominent deployment safety and convenience, high environment and system adaptability, remarkably improved measurement precision, efficient and reliable algorithm and the like.

This application discloses a transformer, a switching power supply, and an air conditioning device. By setting a first shielding layer between the magnetic core and the primary winding, and electrically connecting the first shielding layer to the primary ground, the magnetic core potential is clamped to the primary ground potential, thereby eliminating the displacement current of the magnetic core to ground. An auxiliary winding is set between the primary winding and the secondary winding. The corresponding terminals of the auxiliary winding are opposite to those of the primary winding. The auxiliary winding is connected to the primary ground. The auxiliary winding includes Nb turns of coil, the primary winding includes Np turns of coil, and the secondary winding includes Ns turns of coil, where 2Nb≤3Ns-Np. In this way, a reverse displacement current can be actively created inside the transformer to offset the original interference current, thereby significantly reducing the net current flowing to ground.

The invention relates to the technical field of air sterilization and discloses a distributed multi-stage plasma air sterilization system and method applied to a large space, and the distributed multi-stage plasma air sterilization system comprises an air flow channel, multi-stage plasma generation modules distributed in the air flow channel, and a pulse driving circuit, each stage of plasma generation module comprises a dielectric barrier discharge electrode, the pulse driving circuit detects a charge composite waveform in an electrode gap in a pulse fallback stage so as to obtain a displacement current recovery time constant, and the secondary ozone concentration and the space charge characterization quantity in a flow channel are determined according to the deviation between the constant and a recovery reference. According to the invention, the self-limiting feedback of the product is realized by utilizing a discharge physical process, the contradiction between the disinfection yield demand and the ozone safety threshold value in a large-space environment is effectively reconciled, and the energy self-limiting performance is improved. And the operation safety of the distributed system in a complex environment is ensured.

The invention belongs to the field of power electronics, and discloses an active clamping circuit and method for inhibiting crosstalk of a silicon carbide MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor), symmetrical dual active clamping driving sub-circuits are adopted, and each sub-circuit responds to a driving signal through a control tube and dynamically manages the on-off state of a clamping tube. When the first silicon carbide MOSFET is conducted to cause crosstalk, the control tube on the turn-off side is cut off to enable the clamping tube to be conducted, the gate-source voltage of the second silicon carbide MOSFET is clamped to negative voltage, and forward misconduction and negative breakdown are avoided; during the turn-off period of the double tubes, displacement current is discharged by a low-impedance path of the clamping tube; when the second silicon carbide MOSFET is conducted, the control tube is turned on to turn off the clamping tube, and the voltage clamping is relieved. The circuit overcomes the defects that gate pole resistance affects the switching speed, passive clamping lacks dynamic response and external signal delay exists, and the switching speed, the system reliability and the control cost are considered while crosstalk peaks are restrained; not only is the high-frequency switching advantage of the silicon carbide MOSFET maintained, but also the safety of the grid electrode is protected through accurate voltage clamping.

The application discloses a kind of cable branch box electromechanical collaborative test method, its steps are: using random mechanical excitation force in external environment as passive test source, three-dimensional acceleration mechanical vibration wave and metal shielding ground line wideband weak current of box shell are synchronously collected, and double-mode time sequence is generated;Based on coherent integration algorithm, filter out power frequency induction component, extract induced displacement current and calculate electromechanical conversion coupling coefficient matrix;Using Fourier transform fitting dielectric relaxation response rate, output frequency-dependent dielectric relaxation characteristic vector;Response rate is mapped to different physical depth of insulating layer by combining radial propagation sound path difference model, and radial space charge concentration gradient parameter is output;Based on Poisson equation, reconstruct micro electric field stress distortion curve by reverse integration;Extract maximum stress peak value and compare with dendritic breakdown threshold value, and automatically output adaptive adjustment instruction.The application does not need to apply electrical excitation additionally, and can passively perceive internal space charge distribution and electric field stress distortion of insulating medium.

This application relates to a high-precision non-invasive voltage measurement method, apparatus, computer device, and storage medium based on dual-frequency injection. The method includes: injecting a first detection signal and a second detection signal into a measurement circuit; acquiring a displacement current signal in the measurement circuit; performing signal separation on the displacement current signal based on the signal frequency to obtain a first detection current, a second detection current, and a rated current; and determining the voltage to be measured based on the rated current, the detection voltage, the first detection current, and the second detection current. By injecting the first and second detection signals into the measurement circuit, and obtaining the first detection current, the second detection current, and the rated current based on the obtained displacement current signal, the voltage to be measured is finally determined using the rated current, the detection voltage, the first detection current, and the second detection current. By injecting two reference signals of different frequencies, the influence of resistance and inductance in the measurement circuit can be effectively offset, thereby improving the accuracy of voltage detection.

According to the 4H-SiC MOSFET chip and the main junction region structure and the manufacturing method thereof, the main junction region structure of the 4H-SiC MOSFET chip is characterized in that an N-drift layer is formed on a substrate, a P well is embedded in the N-drift layer, a field oxide layer is arranged on the surface of the P well, the field oxide layer is divided into a plurality of field oxide blocks within the range of the P well, electric field distribution of a transition region is optimized, and the field effect of the N-drift layer is improved; electric field peak intensity is weakened, electric field concentration is avoided, dynamic avalanche breakdown probability is reduced, chip breakdown voltage performance is guaranteed, capacitance distribution of a transition area is adjusted, coupling effect of parasitic gate-drain capacitance is reduced, displacement current is reduced, gate misconduction is avoided, and local temperature rise and stress of the transition area are relieved. The stress transition layer is arranged between the field oxide layer and the P well, thermal expansion and cold contraction differences are reduced, the interface matching performance is improved, the stress transition layer is matched with the field oxide layer, thermal stress concentration can be reduced, the interface crack and stripping risk is remarkably reduced, and the structural stability of the main junction region is improved.

This invention discloses an adaptive compensation voltage divider device based on self-powered bushing end screen. It includes an energy acquisition module that obtains displacement current from the bushing end screen side as power for the voltage monitoring device, and uses a clamping network to protect the circuit from overvoltage damage, converting the AC signal into DC energy. A modulation output module adjusts the equivalent impedance according to the characteristics of the downstream load to optimize power conditions, stores electrical energy, and outputs a measurement signal corresponding to the bushing operating voltage in a timely manner. An adaptive compensation module calculates the operating voltage based on the voltage sampling signal, dynamically updates the compensation coefficient to ensure the accuracy and stability of the voltage divider ratio, and monitors system status feedback information to update the compensation parameters. Implementing this device ensures the accuracy and stability of voltage monitoring, eliminates interference from external leads, and significantly improves the system's anti-interference capability and long-term operational reliability.

By forming a gate lead-out part (232) so as to cover a position (P3) that is at the furthest distance within an inner end portion (241a) of a field insulation film (24) from a contact region (20), electrical field concentration when generating a displacement current is reduced, and dV / dt capability is increased.

The application provides a transient voltage suppressor based on path decoupling and electric field coupling triggering and a manufacturing method thereof. The transient voltage suppressor comprises at least one device unit. The device unit comprises a first electrode and a second electrode, a triggering unit, a main turn-on unit and a coupling unit. The triggering unit comprises a second-conductivity high-doped region and a first-conductivity high-doped region. A local PN junction region is formed between the second-conductivity high-doped region and a first-conductivity low-doped drift region, and the first-conductivity high-doped region is arranged on a coupling dielectric layer. When the local PN junction region is subjected to avalanche breakdown, displacement current is formed through the coupling dielectric layer and coupled to the main turn-on unit, thereby triggering the main turn-on unit to form a longitudinal low-resistance main turn-on path. The main turn-on unit is in a high-resistance state under a static bias condition, so that the static equivalent junction capacitance of the device is mainly determined by the local PN junction region, thereby balancing low junction capacitance, low dynamic resistance and high surge current bearing capacity.

The application belongs to the technical field of electromagnetic prospecting and numerical simulation, and provides a three-dimensional forward simulation method and system for anisotropic medium of electromagnetic method with ultra-wide frequency band, which is based on the vector finite element method, discretizes the electric field equation of unified traditional current and displacement current, fully considers the influence of arbitrary anisotropic conductivity, arbitrary anisotropic dielectric constant and magnetic conductivity, and provides a basis for the theoretical research, field survey and data inversion of the electromagnetic method with ultra-wide frequency band.

The invention discloses a heat dissipation shielding device packaging structure and a process thereof. The process comprises the following steps: mounting a film block on a substrate, stacking a metal block on the film block, integrally packaging and grinding to expose the metal block, etching a packaging material to form a groove, and exposing the surface of the substrate at the bottom of the groove; an adhesive layer is coated on the etched covering surface, and an adhesive layer is also coated in the groove; electroplating a circuit: electroplating a circuit layer on the surface of the adhesive layer along the adhesive layer coating path, and continuing to encapsulate the adhesive layer and the circuit layer; turning over the whole packaging body up and down, exposing the adhesive layer at the position of the film block and the groove, removing the film block, horizontally grinding the surface until the circuit layer at the groove is exposed, and exposing the metal block at the same time; according to the invention, the circuit layer is used as an internal shielding structure, the displacement current is absorbed and guided to the ground, the near-field intensity is reduced, the internal parasitic coupling is inhibited, the distribution of a local electric field is controlled, and a first barrier is formed.

The utility model discloses a high-frequency transformer common-mode noise testing circuit and electronic equipment, and belongs to the technical field of common-mode noise testing. The voltage following circuit is used for isolating and following the excitation signal so as to output the isolated and followed excitation signal; a displacement current is generated between the primary winding with the minimum number of turns in the transformer and the secondary winding under the excitation of the isolated and followed excitation signal; wherein the displacement current is the current between the primary static point and the secondary static point after the primary static point is short-circuited, and the primary static point and the secondary static point are both points with constant voltage; the detection circuit is used for sampling displacement current to output detection voltage; therefore, the possibility that the inductance of the transformer interferes with the excitation signal accessed by the primary winding with the fewest turns is reduced, and the accuracy of the test result is improved.

The invention discloses an electric field energy taking device and method, and the device comprises an energy taking pole plate which comprises an inner pole plate and an outer pole plate, the inner pole plate is arranged adjacent to a power transmission line, the outer pole plate is arranged at the periphery of the inner pole plate in a grid-shaped structure, and a rectification circuit which is connected with the inner pole plate and the outer pole plate and is used for converting a space displacement current Id into a conduction current Ic, the energy storage capacitor is connected to the output end of the rectifying circuit; wherein the outer polar plate is physically cut to form at least two independent grid-shaped units, and equivalent distributed capacitance Ch is increased by utilizing an edge effect, so that the energy taking efficiency per unit area is improved under the condition that the total area of the polar plate is reduced. The grid-shaped electric field energy taking pole plate and the energy taking method thereof have the beneficial effects that the equivalent distributed capacitance is increased by actively utilizing the fringe effect through three specific grid-shaped structure designs of a beam-shaped structure, a ring-shaped structure and a beam ring composite structure, so that the original energy taking efficiency is still kept when the area of the pole plate is reduced by 10%, and the energy taking efficiency per unit area is improved by more than 10%.

The invention relates to the technical field of universe, and particularly discloses a celestial body evolution form exploration method based on an e-p-n quantum entangled state fundamental particle model, which clearly points out the physical property, quantum property, entanglement, magnetic field (bending) property, quantum gravitational field and other basic properties of displacement current based on the e-p-n fundamental particle model. According to the method, the whole evolutionary process of a substance from ultimate quark (U-e-Kp-Kn) to an existing substance is clarified, formation of a galaxis, a fixed star and a planet is deduced on the basis of a substance formation mode of an e-p-n quantum entangled state basic particle model, a more scientific and reliable basis is provided for exploration of a celestial body evolution form, and the research of the evolutionary form of the celestial body is facilitated. And the progress of celestial body evolution form exploration can be further accelerated.

The application discloses a kind of self-driven polarization detectors based on metasurface, belongs to polarization detection technical field.Self-driven polarization detector based on metasurface, including substrate, the upper surface of substrate is provided with several metasurface structure units, metasurface structure unit includes metal patch and bottom patch, metal patch is located above bottom patch, metal patch has non-centrosymmetric structure.Metal patch is Y type metal patch, the material of Y type metal patch is gold, the material of bottom patch is graphene.The self-driven polarization detector based on metasurface and application described in the application, when polarized light is irradiated to the surface of detector, gold-graphene metasurface will produce similar vector photoelectric current with displacement current, according to the difference of photoelectric current size and direction, realize the detection to polarized light, with the advantages of small volume, high degree of integration.

The application provides a full current wave impedance apparent resistivity detection method and system, and belongs to the technical field of survey geophysics. The method realizes apparent resistivity detection of a target area by using a radio frequency magnetotelluric method (RMT). The method mainly comprises the following steps: collecting detection data, using a sensor with a frequency range covering 1 MHz to obtain orthogonal electric field components and magnetic field components at measuring points in a detection area; obtaining dielectric constants and magnetic permeabilities of a shallow surface layer; and using the detection data to calculate full current wave impedance apparent resistivities at the measuring points by using a full current wave impedance apparent resistivity model which is not limited by quasi-static conditions. In the application, the full current wave impedance apparent resistivity model considering displacement current is derived from Maxwell equations, so that the model is not limited by quasi-static conditions and will not cause distortion of apparent resistivity at high frequencies due to non-compliance with quasi-static assumptions. The model can measure both artificial source excited electromagnetic fields and natural electromagnetic fields.

The invention discloses a method for predicting Se vacancy infrared nonlinear optical response in few-layer PtSe2, and the method comprises the following steps: S1, constructing a few-layer PtSe2 model, and carrying out the in-plane expansion; s2, introducing Se vacancy into the model after cell expansion; s3, performing structural relaxation on the Se-containing vacancy structure until atomic force and energy converge; s4, calculating an electron energy band structure of the relaxed structure based on a density functional theory; s5, constructing a maximum localization Wannier function, and fitting the electron energy band structure obtained in the step S4; s6, calculating an in-plane nonlinear displacement current component of the few-layer PtSe2 in an infrared band; and S7, analyzing the change of the nonlinear displacement current component obtained in the step S6 in the infrared band, and predicting the influence of Se vacancy on the infrared nonlinear optical property. The infrared nonlinear optical property prediction method provided by the invention is low in cost and high in precision.

A substrate shielding structure and a method for forming the same, wherein the structure comprises: a substrate; a shielding layer on the substrate, the shielding layer comprising a plurality of mutually separated unit regions arranged along a first direction, each of the unit regions comprising a plurality of coil regions arranged along a second direction, adjacent coil regions being electrically connected to each other, each of the coil regions comprising a first coil, the first coil comprising at least one coil structure, a projection of the coil structure on a surface of the substrate being in an "S" shape; and a guard ring outside the shielding layer and surrounding the shielding layer, the guard ring being grounded and being electrically connected to the shielding layer, so as to reduce an induced magnetic field in the substrate shielding structure, inhibit the formation of a displacement current and a substrate eddy current, and further improve a quality factor Q of the inductor.

The application discloses a method for testing and extracting carrier injection barrier in dielectric, which is based on the relationship between the injection current density and the electric field intensity obtained by the injection charge quantity change rate and the electric field change, and the testing and extraction of the dielectric carrier injection barrier, and comprises the following steps: preparing a dielectric sample; performing electrode unipolar carrier injection test; calculating the conductive current of the carrier migration in the dielectric and the displacement current at the electrode and dielectric interface; calculating the carrier injection current density at the electrode and dielectric interface; correlating the current density and the electric field intensity at the electrode to obtain the carrier injection current density-electric field intensity relationship curve at the electrode interface in the dielectric; performing analysis and fitting to extract the carrier injection barrier. The testing and extraction method can truly reflect the electrical performance parameters of the dielectric under different electric field intensity working states, provides parameters for the charge transport simulation in the dielectric, and has significant scientific and economic benefits.

The application discloses a quality detection method and system of a high-voltage chip under dynamic working conditions. The method comprises the following steps: after ending a preposed dynamic stress working condition, controlling a load loop to discharge residual charge of the chip to be detected to an electrical zero state; acquiring transient characteristics of the preposed working condition to calculate diagnostic pulse parameters; injecting a diagnostic pulse, establishing equipotential shielding between a test cable core and a protective layer, and collecting total leakage current data; calculating a thermal background leakage current estimation value, and performing differential operation on the total leakage current data to separate an electric field degradation leakage current sequence; extracting characteristic parameters of the sequence and comparing the characteristic parameters with a preset reference matrix, and outputting a quality detection result. The system comprises a main control module, an excitation source, a load board and a measurement module. The application effectively decouples thermal effects and insulation degradation, blocks displacement current interference caused by cable parasitic capacitance, and improves the detection accuracy of early insulation defects of high-voltage chips.

This application discloses a power device. The power device includes a silicon layer, an insulating dielectric layer, and an emitter metal layer. The silicon layer includes a floating P-region, a first trench, and a second trench. The first trench and the second trench are spaced parallel to each other along a second direction. The floating P-region is located between the first trenches or between the first trench and the second trench. The insulating dielectric layer is stacked on the silicon layer, and multiple first contact holes communicating with the floating P-region are etched into the insulating dielectric layer. The multiple first contact holes are spaced apart along a first direction. The emitter metal layer is stacked on the insulating dielectric layer, and the emitter metal layer at least partially passes through the first contact holes and connects to the silicon layer. The power device of this application reduces displacement current and enhances the gate's control over EMI and turn-on losses by spaced-apart first contact holes communicating with the floating P-region. At the same time, in areas where first contact holes are not provided, the floating P-region retains the effect of carrier injection, resulting in a lower on-state voltage drop.

To suppress a displacement current in a semiconductor device having a two-stage gate structure and a carrier accumulation layer.SOLUTION: An IGBT 101 includes a carrier accumulation layer 3 of a first conductivity type formed on a first main surface S1 side of a drift layer 2, a base layer 4 of a second conductivity type formed on the first main surface S1 side of the carrier accumulation layer 3, and a gate electrode 9 buried in a trench 7 through an oxide film. The gate electrode 9 includes a lower gate electrode 9D and an upper gate electrode 9U formed closer to the first main surface S1 than the lower gate electrode 9D. In the carrier accumulation layer 3, an impurity concentration of the first conductivity type has a Gaussian distribution in a depth direction, and a depth D1 of an interface between the base layer 4 and the carrier accumulation layer 3 in a vicinity of the sidewall of the trench 7 satisfies D1≥(D2-1.0) [μm] with respect to a depth D2 of the deepest part of an upper gate electrode 9U.SELECTED DRAWING: Figure 1

A safety warning shoe (16) for detecting electric fields is specified, with a detection unit (20) integrated in the safety warning shoe (16) which is configured to measure at least one representative quantity of a capacitive displacement current (I) caused by the electric field (E). V ) to detect between a floor and a person (10) wearing the safety warning shoe (16). Furthermore, a system (15) is specified comprising a safety warning shoe (16) and a warning device (18) separately designed from the safety warning shoe (16).