9191 results about "Electrical polarity" patented technology

The invention is applicable to the field of photovoltaic technology, and provides a back contact solar cell, which comprises a silicon substrate, non-recessed areas and recessed areas are alternately arranged on the backlight surface of the silicon substrate, and the silicon substrate is provided with extending parts extending and protruding to the upper parts of the recessed areas at the edges of the non-recessed areas and the recessed areas; the first dielectric layer and the first polarity doping layer are sequentially stacked on the non-sunken region and the extension part; the second dielectric layer comprises a first part stacked on the first polarity doping layer and a second part stacked in the sunken region; the second polarity doped layer is stacked on the first portion and the second portion. Under the shielding effect of the extension part, the first polarity doping layer in the non-recessed area is effectively isolated from the second polarity doping layer in the recessed area, and electric leakage is avoided.

The invention provides a photovoltaic module and a photovoltaic system, and relates to the technical field of photovoltaics. The photovoltaic module comprises an insulating part, a conductive back plate and a back contact battery piece. The back contact battery piece comprises a collector grid line; the combined parts and the non-combined parts extend in the second direction and are alternately distributed in the first direction, and each of the combined parts and the non-combined parts comprises a part of the collector grid line; the conductive back plate comprises a conductive layer and an insulating layer located between the conductive layer and the back contact battery piece; a through hole is formed in a position, corresponding to at least one combination part, in the insulating layer; the through hole is filled with a bonding material; the current collection grid line of one polarity in the combination part is electrically connected with the conductive layer through a combination material, and the current collection grid line of the other polarity is provided with an insulating part and is insulated from the conductive layer through the insulating part; for one through hole, the ratio of the width of the insulator to the width of the through hole is greater than 1 and less than or equal to 50. The photovoltaic module has the advantages of small hidden crack risk, easy mass production, long service life and good current collection effect.

The invention discloses a back contact electrode structure, a back contact solar cell and a photovoltaic module, and belongs to the technical field of solar cells. The electrode structure comprises current collection electrodes, current collection electrodes, current collection points and current collection areas, the current collection electrodes extend in the first direction, and the current collection electrodes with different polarities are alternately designed at intervals in the second direction; the bus electrodes are distributed on the two sides of the battery substrate in the second direction, the bus electrodes with the same polarity are distributed on one side of the edge of the battery substrate, the bus electrodes with the other polarity are distributed on the other side of the edge of the battery substrate, and the bus electrodes with different polarities are distributed in an array mode in the first direction and are coupled with the part, extending in the first direction, of the collector electrodes with the same polarity; the collector electrodes at least partially extending in the first direction have a segmented design, and the length of the collector electrodes on the two sides of the battery substrate in the first direction is W1lt; and the other collector electrodes are W2 in length.

The present invention provides a composite binder for a sulfide solid-state battery, a preparation method thereof and an application thereof, wherein the composite binder comprises a binder A, a binder B and a solvent, wherein the mass ratio of the binder A to the binder B is (1-10):(5-1), and the mass ratio of the total mass of the binder A and the binder B to the solvent is 1:(10-100). The present invention adopts a binder having a polar functional group and a low-polarity / non-polar binder for combination, thereby making the prepared composite binder have good compatibility with the sulfide solid electrolyte, that is, it does not affect the ionic conductivity of the sulfide solid electrolysis, and at the same time makes the sulfide solid electrolyte membrane have good mechanical properties and flexibility.

The invention relates to a reverse polarity protected electronic circuit with a negative and a positive supply voltage line and with an electrical application circuit. The electrical application circuit has a positive and a negative power supply terminal. The reverse polarity protected electronic circuit comprises a reverse polarity protection circuit (1). The reverse polarity protection circuit (1) has a first and a second N-channel enhancement transistor as part of a reverse polarity protection transistor group (17). The first and second N-channel enhancement transistors are electrically connected in anti-series via a center terminal (86) of the reverse polarity protection circuit (1). The reverse polarity protection circuit (1) includes a control device (4) which is connected to the positive and negative supply voltage lines.Only when connected with the correct polarity does the control device (4) switch the first and second N-channel enhancement transistors of the reverse polarity protection transistor group (17) on. The control device (4) includes its own additional control reverse polarity protection circuit (81) which prevents damage to the control device (4) if connected with incorrect polarity, so that the control device (4) does not switch on the first and second N-channel enhancement transistors if connected with incorrect polarity.

The present disclosure provides a battery cell, a battery, and an electric device. The battery cell includes an electrode assembly, a first output electrode and a second output electrode, and a housing. The electrode assembly includes an electrode body, a first tab, and a second tab with an opposite polarity to the first tab. The first tab and the second tab extend from the electrode body. The first output electrode is electrically connected to the first tab, and the second output electrode is electrically connected to the second tab. The housing is configured to accommodate the electrode assembly. The housing is provided with a pressure relief unit. In a first direction (z), the first output electrode and the second output electrode are disposed at an end of the housing, and the pressure relief unit is disposed at another end of the housing.

The invention provides a distribution line fault location optimization method based on single-ended traveling wave location, and relates to the technical field of traveling wave detection. The method comprises the following steps: carrying out segmented modeling on a line, calculating the traveling wave propagation speed and wave impedance of each segment, and correcting the traveling wave propagation speed and wave impedance; collecting a voltage / current traveling wave signal of a detection point, and extracting a line mode component; performing wavelet transformation on the line mode component, detecting the wave head position of the initial traveling wave through a modulus maximum search algorithm, and recording the arrival time of the initial traveling wave, a corresponding first energy value and polarity; calculating a reflected wave time window based on segmented modeling parameters, screening reversed polarity waves with qualified energy attenuation, and calculating a fault distance; if no effective reflected wave is detected in the reflected wave time window, triggering a pseudo double-end mode; a result is verified through quadruple constraints; the problems of poor parameter adaptability, low signal processing precision, strong reflected wave dependence and incomplete verification in traveling wave distance measurement of a complex distribution line are solved, and the accuracy and reliability of fault distance measurement are improved.

The invention discloses a photovoltaic module and a photovoltaic module preparation method, the photovoltaic module comprises a battery piece, a welding strip, a bus bar and an insulating block, and the back surface of the battery piece is provided with a fine gate electrode and a first insulating layer; the first welding strip is electrically connected with the fine gate electrode with the first polarity, and the second welding strip is electrically connected with the fine gate electrode with the second polarity; the insulating blocks are located on the back face of the battery piece, the insulating blocks and the first insulating layers are alternately arranged in the extending direction of the fine gate electrodes, and the insulating blocks cover part of the fine gate electrodes of the second polarity and part of the second welding strip; the first insulating layer covers part of the fine gate electrode with the second polarity; the bus bar is located in the area, corresponding to the first insulating layer and the insulating block, of the back face of the battery piece, the bus bar extends in the length direction of the fine grid electrode, the bus bar is electrically connected with the first welding strip, and the bus bar is electrically isolated from the second welding strip through the insulating block; and the bus bar is electrically isolated from the fine gate electrode with the second polarity through the insulating blocks and the first insulating layers which are alternately arranged.

The invention relates to a reverse polarity protected electronic circuit with a negative and a positive supply voltage line and with an electrical application circuit. The electrical application circuit has a positive and a negative power supply terminal. The reverse polarity protected electronic circuit comprises a reverse polarity protection circuit (1). The reverse polarity protection circuit (1) has a first and a second N-channel enhancement transistor as part of a reverse polarity protection transistor group (17). The first and second N-channel enhancement transistors are electrically connected in anti-series via a center terminal (86) of the reverse polarity protection circuit (1). The reverse polarity protection circuit (1) includes a control device (4) which is connected to the positive and negative supply voltage lines.Only when connected with the correct polarity does the control device (4) switch the first and second N-channel enhancement transistors of the reverse polarity protection transistor group (17) on. The control device (4) includes its own additional control reverse polarity protection circuit (81) which prevents damage to the control device (4) if connected with incorrect polarity, so that the control device (4) does not switch on the first and second N-channel enhancement transistors if connected with incorrect polarity.

There is provided an electric shaver having (a) a main body that includes a shaver head and a first pair of contacts through which a first voltage is provided, and (b) a cap that is installable on the main body in a first orientation or a second orientation, and when installed on the main body covers the shaver head. The cap has (1) a second pair of contacts that engage the first pair of contacts when the cap is installed on the main body, to receive the first voltage, and (2) a circuit having (i) a diode bridge that receives the first voltage via the second pair of contacts, and provides a second voltage of proper polarity for utilization by other components of the circuit, and (ii) an ultraviolet (UV) light source that utilizes the second voltage, and when ON, emits UV light that irradiates the shaver head.

The invention relates to the technical field of active testing of circuit breakers, discloses an active testing method and system for a circuit breaker, and is used for solving the problem that an existing active testing method is difficult to realize self-adaptive adjustment of a threshold value. Time-frequency analysis is carried out on the contact speed signal to extract time domain and frequency domain features, and heat flow analysis of the thermopile array is combined to obtain a heat engine coupling feature vector; a thermo-electro-mechanical coupling dynamic graph with the sensors and the components as nodes and the reciprocal of thermal conductance as the edge weight is constructed, the structure is updated in real time, and node drift is predicted through a graph convolutional network; fusing the environment derating and the predicted drift amount to adaptively adjust a threshold value; extracting a thermoelectric coupling component of a contact speed fast change component and a heat flow refraction angle change rate, and generating a reversed polarity pulse compensation signal to suppress interference; time synchronization, closed-loop feedback of data and threshold adjustment results are realized through secondary alignment of IEEE1588 and the cloud, graph model node weight and threshold rules are dynamically updated, synchronization with equipment health degree is ensured, and accurate early warning and protection are realized.

The invention relates to a shielding material for a high-voltage cable, in particular to a semiconductor shielding material, a semiconductor shielding layer and a preparation method of the semiconductor shielding layer. According to the invention, a certain amount of modified carbon nanotubes are added on the basis of the raw materials of the existing polymer semiconductor shielding layer added with carbon black, and the modified carbon nanotubes are used for replacing part of carbon black, so that the polymer semiconductor shielding layer with good conductivity and high interface smoothness is prepared. The surface of the modified carbon nanotube is grafted with organic silicon and a polar ethylene polymer, so that the dispersity of the modified carbon nanotube in a polymer semiconductor shielding material system and the compatibility of the modified carbon nanotube with the resin surface are improved; the viscosity of a polymer semiconductor shielding material system under high shear strength is greatly reduced, so that the flowability of the system is greatly improved; the semi-conductive shielding material which is suitable for HV and EHV cables and has super smoothness and strong conductivity is obtained.

The invention relates to a polymer binder for a sulfide solid-state battery as well as a preparation method and application of the polymer binder. The binding agent is formed by copolymerizing vinyl triethoxy silane, 4-vinyl phenylboronic acid lithium and styrene. Silane groups are introduced, the interface adhesiveness with sulfide electrolyte is enhanced through the coupling effect of the silane groups, meanwhile, water in a system is consumed through a condensation reaction, and the water content of an electrolyte membrane is reduced; 4-vinyl phenylboronic acid lithium provides dissociation lithium ions, the ionic conductivity of the binder is improved, and the negative influence on the conductivity of sulfide electrolyte is reduced; the styrene group improves the solubility of the binder in a non-polar solvent. The binder can be dissolved in solvents such as toluene, xylene and the like, and is mixed with sulfide electrolyte to form a film through a wet coating process, and the process compatibility is high. The binder disclosed by the invention has the characteristics of high cohesiveness, ionic conductivity and low water content, and the interface stability and electrochemical performance of the sulfide solid-state battery can be remarkably improved.

The invention provides an electrical equipment remote maintenance guidance method and system. The method comprises the following steps: capturing an aperiodic torque waveform and a magnetic field gradient abnormal signal by deploying a torque fluctuation sensor and a magnetoresistive sensor; performing multi-scale frequency band division on the non-periodic torque waveform, screening out a transient high-frequency component in a start-stop stage of equipment, and separating out a magnetic field polarity reversal characteristic from a magnetic field gradient abnormal signal; performing cross-domain matching on the occurrence time of the transient high-frequency component and the spatial orientation of the magnetic field polarity reversal feature to generate a mixed feature mark; calculating a frequency band overlapping degree based on the time-frequency energy distribution marked by the mixed features and generating a coherence map; and matching a fault historical case library according to the coherence map, and outputting a maintenance strategy set aiming at the rotating shaft dynamic unbalance and electromagnetic interference superposition fault. According to the invention, through fusion of torque fluctuation and magnetic field distortion collaborative analysis, the precision of mechanical and electromagnetic composite fault diagnosis of the rotating shaft is improved.

The invention relates to the technical field of back contact cells, and particularly discloses a back contact cell and a preparation method thereof, and a photovoltaic system, the back contact cell comprises a silicon substrate, and the backlight surface of the silicon substrate is provided with a plurality of first areas and second areas which are alternately arranged; the first semiconductor composite layer is arranged in the first region and comprises a tunneling passivation layer and a first doping layer which are sequentially arranged in the direction away from the silicon substrate; the second semiconductor composite layer is at least partially arranged in the second area and comprises a passivation contact layer and a second doping layer which are sequentially arranged in the direction away from the silicon substrate, and the polarity of the second doping layer is opposite to that of the first doping layer; the composite TCO layer is arranged in at least partial areas of the sides, back to the silicon substrate, of the first doping layer and the second doping layer, the composite TCO layer comprises a first TCO layer and a second TCO layer which are sequentially arranged in the direction away from the silicon substrate, a plurality of holes are distributed in the first TCO layer, and the holes are provided with openings at least in the side, away from the second TCO layer, of the first TCO layer. According to the back contact battery structure, the back reflection effect on light can be effectively improved, the light utilization rate is improved, and then the battery conversion efficiency is improved.

The invention relates to the technical field of photovoltaic, in particular to a back contact photovoltaic module which comprises battery strings and bus bars, each battery string comprises battery pieces and welding strips, the welding strips are connected with the adjacent battery pieces, and the bus bars are connected with the adjacent battery strings; first grid lines with different polarities are arranged on the back surfaces of the battery pieces, the bus bars are arranged on the back surfaces of the battery pieces, the first grid lines extend in the first direction, and the bus bars extend in the second direction; an insulating film is arranged between the bus bar and the first grid line of one polarity, and a conductive film is arranged between the bus bar and the first grid line of the other polarity. In the invention, the bus bar is directly connected with the positive electrode first grid line or the negative electrode first grid line, so that a welding strip does not need to be arranged between the bus bar and the positive electrode first grid line or the negative electrode first grid line, the length of the welding strip can be shortened, the use amount of the welding strip is reduced, and the production cost is reduced. And the bus bar is directly arranged on the back surface of the battery piece, so that the area ratio of the battery piece in the back contact photovoltaic module can be improved, and the photoelectric conversion efficiency is improved.

The invention discloses Zn-I2 battery electrolyte as well as a preparation method and application thereof. The Zn-I2 battery electrolyte comprises an additive, zinc salt and a composite solvent, the additive contains halogen groups and polar functional groups; the halogen group is selected from one or more than two of F, Cl and Br. Through halogen groups in the additive, the iodine negative ion intermediate is effectively stabilized, so that a Zn-I2 battery is subjected to multi-electron transfer, and the specific capacity of the photoelectric storage integrated battery is improved; the polar functional groups in the additive can homogenize the electric field distribution on the Zn surface, reduce the nucleation overpotential corrosion current and hydrogen evolution current of Zn, change the diffusion path of Zn < 2 + > on an anode interface and improve the cycle stability of the Zn-I2 battery, the Zn-I2 battery with high specific capacity and long cycle life can be obtained by matching the two functional groups, and the Zn-I2 battery is coupled with a solar battery, so that the service life of the Zn-I2 battery is prolonged. Therefore, the overall conversion efficiency and the service life of the photoelectric storage integrated battery are improved.

The invention belongs to the technical field of fault detection, and relates to a high-voltage transmission line fault detection and identification method. The method comprises the following steps of: dividing candidate fault sections according to a topological structure by synchronously acquiring steady-state and transient-state traveling wave signals of key nodes of a power grid; identifying a fault by using a multi-feature fusion criterion and extracting traveling wave features; executing mode recognition-based steady-state section judgment and multi-terminal ranging and polarity verification-based transient positioning in parallel to generate two types of positioning result sets; and finally, carrying out intelligent fusion judgment on the two types of results under topological constraints. According to the method, the problems that a traditional single-point signal analysis method cannot determine a fault section, lacks space positioning capability and is insufficient in adaptability are solved, section-level accurate positioning of the fault is realized, and the positioning accuracy, robustness and fault processing efficiency are remarkably improved.

A cable may include a first signal path for communicating a first polarity signal of a differential signal, a second signal path for communicating a second polarity signal of the differential signal, a first deskewer integral to the first signal path and configured to vary a first propagation delay of the first signal path, a second deskewer integral to the second signal path and configured to vary a second propagation delay of the second signal path, attenuators configured to apply an attenuation to the first signal path and the second signal path, and a circuit formed as a part of the cable and communicatively coupled to the first signal path, the second signal path, the first deskewer, the second deskewer, the attenuators, and configured to, based on analysis of the first polarity signal and the second polarity signal, control the first propagation delay, the second propagation delay, and the attenuation.

The invention relates to the technical field of solar cells, in particular to a back contact solar cell module and a preparation method thereof. The back contact solar cell module comprises a cell piece, a bus bar, a plurality of first polarity welding strips, a plurality of second polarity welding strips and an insulating film, wherein the bus bar, the plurality of first polarity welding strips, the plurality of second polarity welding strips and the insulating film are all arranged on the back surface of the cell piece. The first polarity welding strip and the second polarity welding strip are arranged on the back face of the battery piece in a staggered mode, the first polarity welding strip is electrically connected with the bus bar, and the insulating film can isolate the bus bar from the battery piece. The first polarity welding strip and the second polarity welding strip are arranged on the two sides of the insulating film respectively in the thickness direction of the battery piece. The bus bars are arranged on the back surfaces of the battery pieces, so that the space between the battery pieces is saved, the area utilization rate of the back contact battery assembly is improved, the length of the welding strip is shortened, and the collection efficiency of current is improved.

The invention discloses a secondary battery and electric equipment. The secondary battery comprises an electrode assembly and a plurality of tabs, the electrode assembly comprises a plurality of pole pieces and an isolating membrane, and each pole piece is connected with one tab. And the plurality of pole pieces are composed of two outer-layer pole pieces and a plurality of inner-layer pole pieces. One of the two outer-layer pole pieces is a first pole piece, and the pole lug connected with the first pole piece is a first pole lug; the plurality of inner-layer pole pieces comprise a second pole piece, the pole lug connected with the second pole piece is a second pole lug, and the polarity of the first pole piece is the same as that of the second pole piece; and the resistance value of the second tab is greater than or equal to that of any other tab connected with the inner-layer pole piece. The first tab comprises a first part and a second part, the first part is connected with the first pole piece and the second part, the resistivity of the first part is rho1, the resistivity of the second part is rho2, rho1 is smaller than rho2, the resistance value of the first tab is R1, the resistance value of the second tab is R2, and 1.01 R2 is smaller than or equal to R1. According to the secondary battery, the current density of the first pole piece can be reduced.

The invention belongs to the technical field of fuel cell electrode material preparation, and particularly relates to a carbon electrode material for a polypyrrole modified bio-based fuel cell and a preparation method of the carbon electrode material. Comprising the following steps: modifying rice hull low-temperature carbonized powder by sequentially adopting POSS (Polyhedral Oligomeric Silsesquioxane) containing unipolar functional groups and POSS containing polypolar functional groups to obtain modified low-temperature carbonized powder; and carrying out in-situ polymerization on a pyrrole monomer on the surface of the modified low-temperature carbonized powder, and carrying out high-temperature carbonization and hydrofluoric acid corrosion to obtain the polypyrrole modified bio-based fuel cell carbon electrode material. The polypolar functional group POSS not only is beneficial to the in-situ polymerization reaction of pyrrole, but also can form a continuous macromolecular chain, and a net structure is formed on the surface of the whole material. The effect of the unipolar functional group POSS is to improve the stability of the low-temperature carbonized powder in the high-temperature carbonization process, and more importantly, the unipolar functional group POSS is to provide a channel for subsequent hydrofluoric acid corrosion, etch away non-conductive substances and improve the conductivity and specific surface area of the carbon electrode material.

The invention discloses a traveling wave fault positioning method and system for a full parallel AT power supply traction network, and belongs to the field of railway traction power supply system relay protection. The method specifically comprises the following steps: after the full parallel AT power supply traction network has a fault, firstly, analyzing the characteristics of an AT station fault initial current traveling wave, and determining a fault line by using the amplitude of the AT station fault initial current traveling wave; then, the polarity of the fault initial current traveling wave and the fault initial voltage traveling wave of the AT station fault line is used for judging the fault direction; and finally, calculating the fault distance by selecting a positive direction or negative direction distance measurement formula according to the moment when the fault initial voltage traveling wave arrives at the outlet of the traction substation, the AT station and the subarea station and the fault direction information. According to the method, only fault initial traveling wave information is utilized, wave head identification is not needed, wave velocity parameters are not needed, and simulation results show that the positioning method not only can provide fault distance, but also can provide fault line information, is convenient for maintainers to quickly find fault points, and has extremely high robustness and accuracy.

The invention provides a solid electrolyte slurry, an electrode slurry, a solid electrolyte sheet, an electrode sheet, a solid battery monomer, a battery device and a power utilization device.The solid electrolyte slurry comprises a sulfide solid electrolyte material, a solvent and a binder dissolved in the solvent, and the solvent is a non-polar solvent, a weak-polar solvent or a mixed solvent of the non-polar solvent and the weak-polar solvent; the binding agent comprises a polyacrylate binding agent and a non-polar polyolefin binding agent. The slurry disclosed by the invention has high dispersity, high suspension property and good cohesiveness, and can enable the solid-state battery monomer to have high initial coulombic efficiency when being used in the solid-state battery monomer.

The invention discloses a water-based lithium battery positive electrode adhesive, a preparation method and application. The adhesive is of a single-layer or multi-layer shell core-shell structure formed by polar monomers such as acrylic acid, acrylate monomers, cross-linking monomers, self-emulsifying monomers and water through core-shell emulsion polymerization; by controlling the mass percent of acrylate monomers, polar groups and the like in the core layer structure and the shell layer structure and selecting proper types and dosages of cross-linking monomers and self-emulsifying monomers, the adhesive has proper surface tension, shows excellent adhesion and wettability to the current collector, has high peel strength, and is suitable for the current collector. According to the present invention, the lithium ion battery pole piece has the low glass-transition temperature so as to ensure the high toughness, the high surface density, the excellent electrolyte resistance, the excellent electrical property, the excellent coating property and the like of the pole piece, and the raw materials are all non-fluorine materials so as not to produce hydrogen fluoride and other harmful gases during the lithium battery recovery; water is used as a solvent, recycling is not needed, environment friendliness and low carbon are achieved, the manufacturing process is simplified, and the application range is widened.

The invention is suitable for the technical field of solar cells, and provides a back contact cell, a cell assembly and a photovoltaic system. The back contact cell comprises a silicon substrate, a plurality of first polarity fine grids and a plurality of second polarity fine grids. The first polarity fine grid and the second polarity fine grid are arranged on the silicon substrate along a first direction, and the first polarity fine grid and the second polarity fine grid are spaced; the first polarity fine grid comprises a first grid line, the first grid line is provided with a first connecting block, the width of the first connecting block is larger than that of the first grid line, and the length of the first connecting block is larger than or equal to 100 micrometers; the second polarity fine grid comprises a second grid line, the second grid line comprises a first main body part and a first bending part which are connected, the first main body part extends along a second direction, the second direction is crossed with the first direction, and the first bending part is arranged corresponding to the first connecting block and is bent from the first main body part to the direction far away from the first connecting block. Therefore, the connection stability of the back contact battery and the electric connecting piece can be improved.

The application discloses a thunderstorm monitoring device and path planning method of unmanned aerial vehicle based on electric field and magnetic field detection. The device comprises a quadrature magnetic antenna array, a vertical differential electric field sensor, a signal processing module, a positioning algorithm module, a distance estimation module, an autonomous decision module, a GNSS module and an inertial measurement module. The quadrature magnetic antenna array is composed of two orthogonally arranged magnetic antennas, which are at a 45° angle with the flight direction of the unmanned aerial vehicle, and is used for receiving the horizontal magnetic field signal of lightning radiation. The vertical differential electric field sensor comprises two groups of upper and lower electrode plates and measures the differential value of the vertical electric field intensity. Through the cooperative measurement of the magnetic antenna array and the electric field sensor, the lightning azimuth (θ) is calculated by combining the magnetic field intensity ratio, and the quadrant is corrected by using the electric field polarity. Based on the magnetic field amplitude attenuation model and the waveform rise time correction factor, a distance estimation model is constructed. The autonomous decision module generates an approach path or an obstacle avoidance path according to the lightning azimuth and distance, and drives the flight control system to adjust the heading.

The invention discloses a zero common-mode voltage control method and system for two parallel converters based on single vector predictive control, and the method comprises the steps: building a prediction model and an evaluation function with parallel current, three-phase circulating current and common-mode voltage as control targets, and achieving the comprehensive control of output current and three-phase circulating current while guaranteeing the zero common-mode voltage; on the basis of the mapping relation between zero common-mode voltage and switch state combinations, 20 switch combinations with the common-mode voltage being 0 are selected, and an alternative switch combination library is formed; and a common-mode voltage penalty term considering a commutation process and a system parameter error is introduced into the evaluation function, and according to current polarity determination, alternative vectors generating common-mode voltage are rejected online, so that accurate control of zero common-mode voltage is realized. The invention provides an efficient and reliable common-mode voltage suppression scheme, and the common-mode voltage of the two parallel converters is successfully eliminated.

A method and apparatus for the electrochemical polishing of metallic workpieces are proposed, wherein an electrolyte medium containing solid granular particles and a liquid electrolyte is placed in a container and conductively connected to a first electrode, wherein the metallic workpiece is conductively connected to a second electrode and immersed in the electrolyte medium in the container, wherein the electrodes are subjected to an electrical voltage such that the first electrode in contact with the electrolyte medium has a negative voltage and the second electrode in contact with the workpiece has a positive voltage, and wherein the workpiece is moved relative to the majority of solid granular particles of the electrolyte medium in order to polish it electrochemically.The invention provides that the polarity of the electrical voltage applied to the electrodes is temporarily reversed at least once, in particular periodically, during the electrochemical polishing of the workpiece, so that the first electrode in contact with the electrolyte medium temporarily has a positive voltage and the second electrode in contact with the workpiece temporarily has a negative voltage.