5736 results about "Electrical polarity" patented technology

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 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 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 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 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.

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 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 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.

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.

The invention provides a comb-shaped polymer binder, a pole piece and a battery, the comb-shaped polymer binder comprises an acrylate main chain, a flexible soft segment, a polar hard segment and a functional chain segment, the flexible soft segment, the polar hard segment and the functional chain segment are respectively grafted on the acrylate main chain, the flexible soft segment comprises an ether chain segment and / or an ester chain segment, the polar hard segment comprises a polar group and / or a first heteroaromatic ring group, and the functional chain segment comprises a functional group and a second heteroaromatic ring group. The functional chain segment comprises an aromatic ring group containing a pi-conjugated structure and / or a second heteroaromatic ring group containing a pi-conjugated structure. The comb-shaped binder adopts a structural design of'hard section anchoring + soft section buffering + functional side chain ', is helpful for enabling the binder to have high peel strength, stress buffering and electron conduction capabilities at the same time, is compatible with an existing wet coating-rolling process, is helpful for improving the peel strength and prolonging the cycle life of an electrode plate when being used for preparing the electrode plate, and is beneficial for improving the service life of the electrode plate. And the rate capability of the battery is improved.

The invention discloses a power transmission line fault positioning method and system based on ground potential end transient information perception, and relates to the technical field of line fault positioning, and the method comprises the steps: obtaining a voltage traveling wave signal and a current abrupt change rate signal detected by a trunk line and branch node sensor array in a power transmission line; processing the voltage traveling wave signal and the current abrupt change rate signal to obtain traveling wave components and polarity-amplitude calibration results of different modes; according to traveling wave components and polarity-amplitude calibration results of different modes, in combination with topological parameters of the power transmission line and spatial distribution of a ground potential end sensor, adjusting edge weights or connection relationships in the graph structure to obtain a composite feature matrix and an edge weight matrix of each node; and inputting the composite feature matrix and the edge weight matrix of each node into a graph neural network positioning model, and outputting a power transmission line fault positioning result. According to the invention, through ground potential end information fusion and the dynamic graph neural network, accurate fault positioning under a complex power transmission topology is realized.

The invention provides a photovoltaic module and a preparation method thereof, and relates to the technical field of back contact cells. On the back face of a first battery piece of the photovoltaic module, an insulating strip covers the first sections of a plurality of first polarity welding strips and the ends of a plurality of second polarity welding strips, the second sections of the first polarity welding strips and a bus bar are arranged on the side, away from the first battery piece, of the insulating strip, and the bus bar is connected with the second sections. And the bent section of the first polarity welding strip is connected with the first section and the second section respectively. The insulating strip does not exceed the edge of the first battery piece, and the end part of the first polarity welding strip does not exceed the edge of the first battery piece. And the second battery piece is connected with the bus bar on the first battery piece. The two adjacent battery pieces are seamlessly spliced through the mode that the welding strips are bent and connected with the bus bars, hiding of the bus bars is achieved in the photovoltaic module, the photovoltaic module is simple in structure, the technology is simplified, and cost is reduced.

The invention provides a display device and a driving chip of a display panel. The display device comprises the display panel and the driving chip. The driving chip comprises a first comparator and a second comparator; the driving chip is used for dividing the output channels corresponding to the at least two data lines into a first channel with positive polarity and a second channel with negative polarity; a first comparator for comparing the first voltage with a first reference voltage to output a first level; the second comparator is used for comparing the second voltage with a second reference voltage and outputting a second level; and the driving chip is also used for continuously monitoring the first level and the second level so as to detect whether a short circuit between the data lines occurs in the display panel or not. The data line is divided into the positive and negative polarity channels through the driving chip, the comparator is used for comparing the channel voltage with the reference voltage, the level change is monitored to detect the short circuit, an amplifier and a complex switch assembly do not need to be additionally arranged, the circuit structure is simplified, and the manufacturing cost is reduced.

A control system for an AC-DC converter includes a mixed-signal power controller and first and second gate drivers. The controller has a digital module and an analog module. The analog module has a current sensor generating a current sense voltage based on a sensed switch current. The digital module has a DC voltage sensor generating a DC sense voltage based on a DC bus voltage, and an AC voltage sensor generating an AC sense voltage and a binary polarity signal based on the AC voltage. The digital module induces the first gate driver to output first and second control signals for controlling a high-side switch and a low-side switch of a current shaping half-bridge based on first and second clock signals and the comparator voltage, such that an inductor current flowing through an inductor is proportional to a current command value.

The invention relates to the technical field of electric energy conversion control, and discloses a multi-source load auxiliary power supply power balance control system, which comprises a sampling module, a control module and a modulation module, the sampling module obtains parallel converter branch current and direct current bus voltage; the control module determines a weight by utilizing physical associated association of a bus voltage change gradient and branch current change polarity, corrects a dynamic slope factor determined by a current change rate according to the weight, and performs upper limit clamping on the dynamic slope factor according to a bus voltage margin; according to the invention, the rigid restriction of droop control logic is eliminated, the power deviation generated by asymmetry of feeder impedance is automatically offset while the bus voltage stabilization precision is maintained, and the convergence speed and the certainty of the system during violent load switching are improved.

The invention discloses a motor control method and device, electronic equipment and a storage medium. The method comprises the following steps: acquiring a three-phase current, converting the three-phase current into a total current of a current period in a static coordinate system, and extracting a high-frequency current of the current period from the total current; extracting a rotor position and a rotor rotating speed from the high-frequency current; compensating the rotor rotating speed by using the expected rotating speed to obtain a quadrature-axis expected current; converting the total current into a quadrature-direct axis coordinate system, extracting a fundamental frequency current from the quadrature-direct axis coordinate system, compensating the fundamental frequency current by using a quadrature axis expected current and a direct axis bias current to obtain a first expected voltage, superposing the first expected voltage and a direct axis high-frequency voltage, and performing coordinate system conversion on a superposition result by using a rotor position to obtain a second expected voltage; obtaining a second expected voltage under the static coordinate system; and the three-phase current of the current period is controlled according to the second expected voltage to drive the motor, so that the motor has more obvious salient polarity through the direct-axis bias current, and vector control over the electrode is achieved.

The invention belongs to the technical field of back contact batteries, and particularly relates to a back contact battery with a specific electrode insulation structure and a manufacturing method and application of the back contact battery with the specific electrode insulation structure. Breakpoints are arranged at the intersection areas of the fine gate electrodes and the main gate electrodes with different polarities and are distributed discontinuously, first insulating layers are arranged on the outer surfaces of partial areas of the breakpoints of the fine gate electrodes, and the first insulating layers cover the breakpoints and extend into the isolation grooves in the Y-axis direction of the back contact cell substrate. The main gate electrode is located on the outer surface of the first insulating layer and located at the breakpoint of the fine gate electrode, and a second insulating layer is arranged on the outer surface of the end of the breakpoint of the fine gate electrode. According to the invention, the problem of printing broken gate when the small opening of the main gate electrode is arranged (namely, the width is narrow) can be avoided, the manufacturing of the superfine main gate electrode is realized, the consumption of silver paste is reduced, and the cost is reduced; meanwhile, the average power and the low short-circuit rate of the battery string are improved.

The present invention discloses a front-terminal vertical wide-tab direct-connected bipolar lead-acid battery and an assembly method thereof. Specifically, a new battery structure is proposed, in which the busbars between the single compartments in a conventional battery are removed, and the connection between the single compartments is replaced by a bipolar plate connection method. The plates and separators are stacked horizontally into a battery slot layer by layer in a specific arrangement order, the tabs are widened, and a row of holes are punched in the middle of the tabs of the bipolar plates. After the lamination is completed, metal rods are inserted into the holes to connect the pole groups and tabs in parallel, the pole groups are locked with a pressing plate, and each monomer is sealed by glue injection. The two halves are then bonded into a whole by glue sealing or heat sealing, and the battery is turned into an upright state. The busbars at the turning points are welded, the terminals are welded, and the side covers are sealed to complete the battery assembly. This structure can greatly improve the high-current and high-rate discharge performance of the battery, and effectively solve the high-rate discharge and assembly problems of lead-acid batteries, providing key support for technological innovation, performance breakthroughs and market expansion of lead-acid batteries.

The invention provides a power distribution network zero sequence mutual inductor wiring polarity on-line proofreading method and system. The method comprises the following steps that 1, an active inverter is directly connected between a phase line of a power distribution network or a neutral point of a grounding transformer and the ground, or is connected between the phase line of the power distribution network or the neutral point of the grounding transformer and the ground through a boosting transformer; step 2, performing closed-loop control on the active inverter to inject zero-sequence current into the power distribution network; 3, in the injection process, judging whether the wiring polarity of the zero-sequence mutual inductor is wrong or not; 4, if only one of the zero-sequence voltage transformer and the zero-sequence current transformer has a wiring polarity error, correcting by modifying a software flag bit; and step 5, each power distribution terminal and the accessory device thereof complete online calibration of the wiring polarity of the zero sequence mutual inductor. By applying the technical scheme, the problem that the grounding fault section positioning research and judgment result is wrong due to the wiring polarity error of the zero-sequence mutual inductor of the power distribution terminal and the accessory device thereof can be avoided, and the method has good engineering application value.

The invention discloses a cable insulation space charge simulation method and device based on aging factor coupling, and relates to the technical field of electrical engineering. The method comprises the following steps: establishing a bipolar carrier charge transport model, wherein model parameters comprise a detrapping coefficient and a diffusion coefficient; sampling the cable insulation, and measuring the isothermal relaxation current of the sample to calculate the aging factor of the sample; measuring the actual carrier mobility of the sample by using a time-of-flight method; a detrapping coefficient is updated based on the aging factor, a diffusion coefficient is updated based on the actual carrier mobility, and an aging factor coupling type insulation charge transport model is obtained; and carrying out numerical solution on the aging factor coupling type insulation charge transport model to obtain simulation data of space charge distribution and local electric field change of cable insulation. According to the technical scheme, space charge distribution and local electric field change of cable insulation are accurately simulated, and scientific evaluation can be provided for the aging state of cable insulation.

A back-contact solar cell, a battery assembly and a photovoltaic system. In the back-contact solar cell, several grooves arranged at intervals are formed in a back surface of a silicon wafer, so as to divide the back surface of the silicon wafer into several first regions and second regions that are alternately arranged in sequence, in an arrangement direction of the first regions and the second regions, the silicon wafer is provided on the first regions and the edges of the grooves with extension portions that extrude to the upper side of the grooves, and second polarity doping layers are disposed on second tunneling layers in a stacked manner and have a preset distance with the edges of the grooves.

The invention is suitable for the technical field of solar cells, and provides a solar cell and a manufacturing method thereof, a cell module and a photovoltaic system. The solar cell includes: a silicon substrate including a doped layer; the fine grids are arranged on the silicon substrate and are electrically connected with the doping layer; the passivation layer comprises a first passivation part and a second passivation part, the first passivation part at least partially covers the area, exposed from the fine grid, of the silicon substrate, and the second passivation part at least partially covers the fine grid. Therefore, the first passivation part of the passivation layer at least partially covers the part, exposed from the fine grid, of the silicon substrate, and the second passivation part at least partially covers the fine grid, so that the fine grid is at least partially covered by the passivation layer, oxygen, water vapor and pollutants can be isolated, and the risk that the fine grid is oxidized or corroded is reduced. Moreover, the second passivation part can provide insulation for the fine grid covered by the second passivation part, and the risk that the surface, covered by the second passivation part, of the fine grid is conducted with a structure with non-corresponding polarity is reduced.

The invention discloses a zinc-bromine flow battery multifunctional negative electrode electrolyte and a preparation method thereof, and belongs to the technical field of electrochemical energy storage, and the method comprises the following steps: uniformly stirring and mixing a solvent, deionized water and a cosolvent, adding an electrolyte, stirring until the electrolyte is completely dissolved, then adding a supporting electrolyte and a negative electrode additive, stirring until the supporting electrolyte and the negative electrode additive are completely dissolved, and obtaining the zinc-bromine flow battery multifunctional negative electrode electrolyte. The multifunctional negative electrode electrolyte of the zinc-bromine flow battery is obtained; the negative electrode cosolvent is dimethylformamide; and the negative electrode additive is at least one of saponin and cinnamyl aldehyde. Saponin molecules are adsorbed on the surface of the zinc electrode, and electronegative carboxyl groups of the saponin molecules form an electrostatic repulsion net in an electric double layer, so that zinc ions are forced to be uniformly dispersed, local ion concentration hot spots are eliminated, and dendritic crystal nucleation is inhibited from the source. In cinnamyl aldehyde, the strong electronegativity of oxygen atoms and the electronegativity of aldehyde oxygen are far higher than those of hydrogen, so that electrons are strongly attracted, adjacent carbon atoms are positively charged, polar adsorption sites are formed, the hydrogen evolution reaction is effectively inhibited, and the stability and the cycle life of the battery are greatly improved.

The invention relates to the technical field of fuel cell control, and discloses a control method of a hydrogen fuel system controller, which comprises the following steps: in response to a system shutdown instruction, controlling a DC / DC converter to maintain operation and request a preset scavenging current, and consuming residual reaction gas in a flow channel and a pipeline by using an electrochemical power generation reaction in an electric pile; meanwhile, hydrogen-cut air-down operation is executed, and the average single voltage of the electric pile is collected in real time; when it is monitored that the average monomer voltage is reduced to be below a preset anti-corrosion safety threshold value, the DC / DC converter is controlled to be disconnected, and mechanical purging is started. A time sequence interlocking mechanism of electrochemical energy depletion and mechanical purging is established, a high-potential retention path in the shutdown process is blocked from the physical and chemical source, and the safety of the shutdown is improved. Reverse polarity corrosion caused by a hydrogen-air interface effect is avoided, and the service life of the galvanic pile is prolonged.

The invention provides a transformer partial discharge positioning method and device based on bushing CT acquisition. The method comprises the following steps: acquiring a high-frequency partial discharge pulse signal of a current transformer at a transformer bushing; background noise of the pulse signal is removed, amplitude correction is carried out, and a corrected pulse signal is obtained; judging whether the partial discharge belongs to external interference or internal partial discharge based on the polarity distribution rule of the corrected pulse signal; if the interference is external interference, comparing the amplitudes of the correction acquisition signals corresponding to the bushings, and taking the position corresponding to the current transformer with the maximum amplitude as an interference source injection position; if partial discharge occurs in the transformer, calculating the distance proportion from the partial discharge position to the head end of the winding according to the attenuation characteristic of the pulse signal propagating in the winding and the pre-injected calibration square wave signal so as to determine the discharge position. According to the method, the method for determining the partial discharge position of the transformer is simplified, external interference and internal partial discharge signals can be quickly identified, and misoperation of a protection device is avoided.

A back contact solar cell, a preparation method and a battery assembly, which belong to the technical field of crystalline silicon solar cells. The back contact solar cell comprises: a semiconductor substrate, the back surface of which includes first polarity regions and second polarity regions alternately arranged in a first direction; a first functional layer, which is disposed in the first polarity regions; a second functional layer, which is disposed in the second polarity regions; a laser protection layer, which is disposed on the side of the second functional layer away from the semiconductor substrate and exposes electrode contact regions of the second functional layer, wherein the material of the laser protection layer includes laser absorption material; first electrode structures, which are disposed on the side of the first functional layer away from the semiconductor substrate; and second electrode structures, which are disposed on the side of the second functional layer away from the semiconductor substrate and located in the electrode contact regions.

A substrate processing system comprising: a plasma processing apparatus; a depressurization transfer device having a transfer robot and an edge ring; and a controller is disclosed. The plasma processing apparatus includes: a depressurizable processing chamber; a substrate support table; a lifting mechanism; a gas supply part; and a plasma generating part. The controller controls following steps to be performed in following order: (a) performing plasma processing on the substrate and, then, applying a voltage of a first polarity to the electrode; (b) neutralizing the edge ring, by applying a voltage of a second polarity to the electrode while supplying a gas, and stopping the application of the voltage to the electrode after a predetermined period of time elapses; (c) separating the edge ring from a ring placing surface of the substrate support table; and (d) transferring the edge ring from the processing chamber to the depressurization pressure transfer device.

The invention is suitable for the photovoltaic technical field, and provides a photovoltaic cell, a cell assembly and a photovoltaic system, the photovoltaic cell comprises a semiconductor substrate, a first polarity doping layer and a second polarity doping layer; the back surface of the semiconductor substrate comprises a plurality of doped regions, the doped regions comprise first regions and second regions, the first regions and the second regions are alternately arranged, the first regions and the second regions are connected through connecting regions, first polarity doped layers are stacked on the first regions, and second polarity doped layers are stacked on the second regions; the first polarity doping layer and the second polarity doping layer in at least part of the connection area are in composite contact to form a composite contact area; the absolute value of the difference between the reflectivity of the connection region and the reflectivity of the doped region is greater than 0.05%. Connection areas form composite contact, the problem of hot spots is solved, meanwhile, damage to the battery piece caused by additional machining is avoided, the production cost can be reduced, and meanwhile the recognition accuracy and efficiency of a machine vision system on the photovoltaic battery can be guaranteed.

The invention provides a concentric circle circulating flow sewage treatment system based on electric strengthening and a control method. The system comprises a concentric circle circulating flow reactor, a microbial electric strengthening unit and an AI driving control unit, a concentric circle double-ring gallery and multi-point water inlet and multi-point backflow achieve a complete mixed flow type flow state of transverse plug flow and longitudinal circulation flow, the concentric circle circulation flow state is coupled with the microbial electric strengthening unit to form gas-liquid-solid-electricity four-phase turbulent flow to break a mass transfer boundary layer, and the contact efficiency and the mass transfer efficiency of sewage and microorganisms are strengthened. The anodes and the cathodes of concentric circle structures are closely arranged to generate electric field gradient to regulate and control spatial distribution of microbial communities, dynamic polarity switching is achieved through an AI system, the reactor is endowed with the self-adaptive capacity for coping with water quality fluctuation, and the sewage carbon, nitrogen and phosphorus removal treatment efficiency is improved in a breakthrough mode.

The invention discloses a soft switching HERIC non-isolated inverter and a modulation method thereof, and belongs to the technical field of inverters, the inverter comprises a bridge arm circuit, a clamping circuit, a resonance circuit, a voltage stabilizing circuit and a filter circuit, the resonant circuit comprises a first auxiliary switch tube, a second auxiliary switch tube, a third auxiliary switch tube, a fourth auxiliary switch tube, a first resonant inductor, a second resonant inductor, a first resonant capacitor and a second resonant capacitor; all high-frequency switches realize zero-current turn-on and turn-off at the same-direction stage of the voltage and the current of the power grid through the resonance circuit; all the high-frequency switches also realize zero-current switching on and switching off in the voltage and current reverse phase of the power grid; according to the modulation method, unipolar PWM modulation is adopted, the grid-connected current harmonic distortion rate is reduced, the grid-connected electric energy quality is improved, and the application value and prospect are huge.