4047 results about "Contact resistance" patented technology

The invention relates to the technical field of data processing, in particular to an intelligent analysis system for electric energy quality and read data, which comprises a data fusion module, a modeling module, an analysis module, a detection module, an optimization module and a control module. The data fusion module aligns data of an electric meter terminal, power grid monitoring equipment and an environment sensor through a sliding time window, and the analysis module calculates a power grid node loss transfer coefficient based on a graph neural network and fuses transformer no-load loss and line contact resistance parameters to generate a dynamic line loss evaluation matrix. And the detection module identifies the power consumption characteristic deviation degree through a random forest classifier, and generates a priority management strategy in combination with a multi-dimensional abnormal scoring model. The control module adaptively selects a communication protocol to execute a regulation and control instruction according to a network state, a heartbeat detection mechanism feeds back operation data of a governance device in real time, model parameters are driven to be iteratively updated, and dynamic cooperation of power supply quality optimization and line loss governance is achieved.

The invention discloses a silver paste coating conductive uniformity test system and a test method, particularly relates to the technical field of silver paste coating conductive test, and is used for solving the problem that the silver paste coating conductive uniformity test is inaccurate. Through a high-precision pressure sensor and a camera device, contact state data of a probe are monitored in real time at each measuring point, a contact state matrix is generated to support accurate correction of contact resistance, after collected data are subjected to standardization processing, a support vector regression model is used for capturing a nonlinear relation, and the accuracy of the contact resistance is improved. The method comprises the following steps: optimizing a compensation model through cross validation and parameter tuning, setting an optimal pressure range to stabilize a contact condition and smoothly process data, correcting time deviation by adopting a multi-channel data acquisition and distributed sampling synchronization algorithm, correcting an error in combination with a compensation coefficient, and finally calculating a conductivity uniformity index through a resistance data matrix. Heat map classification evaluation is generated, a low-degree uniform region is repaired, and the consistency and reliability of a conductive uniformity test are remarkably improved.

The invention relates to the technical field of packaging of power electronic devices, in particular to a three-dimensional packaged double-sided heat dissipation power module. The structure comprises an upper active metal brazing base material substrate and a lower active metal brazing base material substrate, a plurality of silicon carbide MOSFET chips, conductive strips and an inserter used for fixing the chips are arranged between the upper active metal brazing base material substrate and the lower active metal brazing base material substrate, the upper half-bridge chip is annularly arranged around a direct-current positive terminal, the lower half-bridge chip is annularly arranged around a direct-current negative terminal, and heat dissipation channels are formed in the upper surface and the lower surface of each chip. The impedance of branches is controlled to be equal, the current of each branch chip is balanced, the distance and layout of the chips are optimized, the overall loop area is reduced, the parasitic stray inductance of the module is reduced, in addition, the chips and the substrate are connected in a crimping mode, the chips and the copper columns are in contact through pressure to achieve electric heat conduction, the crimping materials are graphene sheets and molybdenum sheets, and the cost is low. Good contact between the chip and the copper columns is ensured, and contact resistance and thermal resistance are reduced. According to the invention, the effects of improving the heat dissipation efficiency, reducing parasitic stray inductance, balancing the current distribution of the parallel chips, and enhancing the module reliability and the conversion efficiency are achieved.

The invention relates to the technical field of big data analysis, in particular to a contact defect detection system and method based on big data, and the system comprises a multi-dimensional data capture module, a time sequence analysis module, a trend evaluation and anomaly recognition module, a future state prediction module, and a fault classification and diagnosis module. According to the invention, by deeply capturing and screening contact operation state data, the accuracy of input data is ensured, abnormal interference of contact resistance is avoided, the data validity is improved, current impact fluctuation points are identified, the sensitivity to operation abrupt change is enhanced, the accuracy of time sequence analysis is ensured, long-term offset is tracked, the wear identification capability is improved, and the future state is accurately predicted. The method is advantaged in that maintenance plan precision is improved, contact pressure reduction trend is analyzed, fault classification is refined, defect identification accuracy is improved, data screening, trend tracking, offset characteristic calculation and fault classification are optimized, accurate detection is realized, and equipment reliability and operation safety are improved.

The invention relates to a production method of a battery piece. The production method comprises the following steps: printing a grid line electrode on the battery piece; sintering the grid line electrode; cutting the battery piece; forming a passivation layer on the cutting edge of the battery piece; and applying voltage and laser to the battery piece so as to anneal the grid line electrode and the passivation layer. According to the application, the voltage and the laser are applied to the battery piece to anneal the grid line electrode, so that the contact resistance between the grid line electrode and the battery piece can be reduced; and the passivation layer is annealed, so that the passivation degree of the passivation layer on the cutting edge can be improved, and the photoelectric conversion efficiency of the produced battery piece is further improved. According to the method, after the passivation layer is formed on the cutting edge of the battery piece, the voltage and the laser are applied to the battery piece, a grid line electrode and the passivation layer can be annealed at the same time, the time for repeatedly arranging equipment for applying the voltage and the laser is saved, the passivation degree of the passivation layer is improved, the production time of the battery piece is shortened, and the production efficiency of the battery piece is improved. And the production efficiency of the battery piece is improved.

The invention relates to the technical field of target detection, in particular to an AI visual identification technology-based power monitoring system, which comprises a multispectral monitoring module, a thermal anomaly identification module, a dynamic region correction module, a structure trend prediction module and an abnormal mode judgment module. According to the method, the visible light image and the infrared thermal imaging data are subjected to joint analysis, the appearance contour, the component arrangement and the thermal feature information of the power equipment are extracted from multiple angles, equipment identification and temperature anomaly detection are realized, a sliding time window is constructed to extract the morphological change gradient, and the structural degradation trend of the equipment is accurately predicted. Through calculating the joint posterior probability distribution of the abnormal parameters such as the cable current-carrying capacity, the switch contact resistance value and the line power factor, and comparing the probability gradient value of the abnormal mode, the abnormal mode matching is realized, the equipment fault early warning capability is improved, and the accuracy of target detection, the precision of abnormal identification and the reliability of equipment state evaluation are improved.

The utility model relates to an electric control assembly and a vehicle. The electric control assembly comprises a power module and a capacitor. The positive terminal and the negative terminal of the power module each comprise a first horizontal lead-out part parallel to the power module body. The main body parts of the first horizontal lead-out parts of the positive terminal and the negative terminal of the power module are completely stacked and arranged at intervals; the positive terminal of the power module is welded with the positive terminal of the capacitor, and the negative terminal of the power module is welded with the negative terminal of the capacitor. By adopting a welding mode, the strength of the welding position between the terminals is increased, the vibration durability and reliability are enhanced, the contact resistance between the terminals is reduced, and the thermal risk is reduced. And the positive and negative terminals of the power module do not need to be staggered and avoided for mounting screws, so that the main body parts of the first horizontal lead-out parts of the positive and negative terminals of the power module can be completely stacked, the equivalent series inductance between the positive and negative terminals is reduced, the switching loss of the power module is reduced, and the working efficiency is improved.

The invention relates to the technical field of wiring terminals, in particular to an intelligent testing method and system for the contact resistance of a wiring terminal, and the method comprises the following steps: adjusting the resistance testing frequency according to the environment temperature to adapt to different conditions, combining current and voltage data, analyzing the historical change trend of the resistance, predicting the potential change range, and obtaining the contact resistance of the wiring terminal through the current and voltage data. Evaluating the mutual influence with the resistor, judging the abnormal reason of the resistor, adjusting a test scheme according to fault diagnosis, predicting potential faults, and making a test plan. According to the invention, through environment induction and data analysis, the resistance test frequency is adjusted in real time to adapt to environment change, so that the resistance measurement in the test process is more sensitive and accurate, the response speed and data quality of the test process are improved, historical and current resistance data are automatically analyzed, potential faults can be effectively predicted and identified, and the test efficiency is improved. Problems caused by operation errors are reduced, and a prospective fault prediction function enables the adjustment of the test period to be more scientific.

An interconnection structure, including: a first BEOL (Back-End-Of-Line) level which includes a first MLG (Multi-Layer Graphene) layer which includes at least one first line structure of MLG material; and a first isolation layer which includes an electrically isolating material and is disposed above and beside the at least one first line structure of MLG material; a second BEOL level which includes a second MLG layer (includes MLG material) disposed above the first isolation layer; a connection path electrically connecting first MLG layer to second MLG layer; and at least one via with serrated edges mitigating misalignment impacts and providing low via to line contact resistance, where the connection path includes one of the at least one via, where a width of the at least one first line structure of MLG material is greater than a diameter of the one of the at least one via, and where both MLG layers are intercalation doped.

The invention provides an electric energy metering detection data quality evaluation method and system, and relates to the field of data processing. Data abnormity generated by a current transformer aiming at gradual change characteristics caused by contact oxidation is firstly eliminated through improved wavelet transform and feature extraction; the abnormal rate of the processed data is calculated according to a support vector machine model, the conditions of noise interference and abnormal fluctuation in actual current data are considered when a support vector machine is designed, and the contact resistance is slowly increased due to contact oxidation of the secondary winding of the current transformer; therefore, the problems that the gradual change abnormity is difficult to find in time and the electric charge metering deviation is easily caused by the existing fixed threshold value evaluation method are solved.

The invention discloses a manufacturing method of a two-dimensional semiconductor field effect transistor based on a high-k gate dielectric integration technology capable of eliminating a buffer layer. The manufacturing method comprises the following steps: depositing a back gate electrode and a back gate dielectric on a substrate in sequence; transferring the channel layer to the back gate medium; sequentially forming a buffer layer, a source electrode, a drain electrode, a top gate dielectric layer formed by a high-k dielectric material and a top gate electrode on the channel layer; and annealing treatment is carried out in a vacuum environment, and the buffer layer sublimates, so that Van der Waals interfaces are formed between the channel layer and the top gate dielectric layer and between the channel layer and the source electrode as well as between the channel layer and the drain electrode. According to the high-k gate dielectric integration technology based on the erasable buffer layer, the erasable buffer layer after vacuum annealing is utilized, damage to a two-dimensional material is avoided, a high-quality high-k gate dielectric is deposited, interface regulation and control between a channel layer and a top gate dielectric are achieved, and the equivalent oxide thickness is reduced; and good contact between the channel layer and source and drain metal is realized, the contact resistance of the transistor is reduced, and the electrical performance of the transistor is improved.

The invention provides a multi-channel contact resistance intelligent test device and method, the contact resistance intelligent test device is integrated with a plurality of different types of resistance test channels, and the resistance test channels comprise a conduction test channel, a static resistance test channel and a dynamic resistance test channel. The device comprises an upper control module used for receiving a channel test parameter of a contact resistor and generating a channel selection test instruction based on the channel test parameter; the multi-channel switching module switches to a target test channel of a corresponding type based on the channel selection test instruction; the resistance measurement module applies current of a corresponding type according to the type of the target test channel, collects the voltage of the target test channel, and obtains a resistance value according to the voltage and the current; and the signal processing module performs noise reduction processing on the resistance value to obtain a target resistance value, and evaluates the change trend of the target resistance value, so that the problems of low test efficiency, dynamic data missing and personal error accumulation of a traditional method are solved, and the subjective deviation of manual interpretation is eliminated.

The invention discloses a solar cell and a photovoltaic module, and the solar cell comprises a cell body which comprises a first surface and a second surface which are opposite to each other; the passivation layer is at least arranged on the first surface, and a plurality of holes penetrating through the thickness of the passivation layer are formed in the passivation layer; the seed layer comprises a part corresponding to the open hole and an extension part extending from the open hole to one side, far away from the battery body, of the passivation layer; the ratio of the width of the extension part along the first direction to the thickness of the extension part along the thickness direction of the battery body is 0.5-10; the first direction is parallel to the first surface. According to the present invention, the sufficient adhesion between the seed layer and the cell body can be ensured, the falling risk can be reduced, the moderate contact area between the seed layer and the electrode can be ensured, and the contact resistance between the seed layer and the electrode can be small.

The invention discloses a preparation method and application of a novel ionized water gel-based moisture power generation material. The material is composed of a carbon coating fabric, ionized water gel and a patch metal electrode. Wherein the nano carbon black is used as a conductive filler of the hydrogel and can enhance electric energy output by promoting functional group dissociation and ion migration. The high-hygroscopicity sea salt in the hydrogel can enhance the capture and transmission capability of the material on water molecules in the atmosphere, and ensures the continuous power output capability of the moisture power generation material. Due to the design of the zigzag dry-wet interface, the wettability between the hydrogel and the carbon black coating can be improved, the moisture absorption rate is increased, the contact area is increased, and therefore the power generation power is improved. The metal patch electrode can ensure the stability of long-term power generation of the material, and can be customized to reduce the contact resistance. A moisture power generation device prepared from the material can be used as a passive energy supply device and is suitable for the fields of self-powered sensors, wearable electronic equipment and the like.

The invention relates to the technical field of equipment maintenance, in particular to a distribution box remote diagnosis and maintenance system which comprises a voltage deviation detection module, a node hot stacking identification module, a channel stability classification module, a contact aging trend evaluation module and a period adjustment trigger module. According to the method, peak value change of effective voltage in each channel period in the distribution box is collected and compared with a preset criterion so as to accurately identify an abnormal discharge unit and accurately position a potential risk channel, and the change rate of equivalent series capacitance, contact conductance and contact resistance of a node is continuously sampled in a non-power-on state so as to accurately identify the potential risk channel. According to the method, multi-parameter same-trend change characteristics are determined, the contact aging process is accurately evaluated by integrating the parameter trend, the node trend and the maintenance plan period remaining time are subjected to cross comparison, the maintenance task advance opportunity is automatically judged, the maintenance plan is actively adjusted, the node fault missing detection risk is effectively reduced, and the maintenance timeliness and accuracy are remarkably improved.

The invention belongs to the technical field of back contact cells, and particularly relates to a joint passivation back contact cell and a post-texturing preparation method thereof, and the method comprises the steps: S102, sequentially forming a first semiconductor layer and a mask layer on the back surface of a silicon substrate; s103, cleaning and texturing are carried out, so that a texturing surface is formed on the light receiving surface of the silicon substrate, and the maximum height of a pyramid of the texturing surface of the light receiving surface is T1; s104, sequentially forming a passivation layer and an anti-reflection layer on the light receiving surface of the silicon substrate; s105, forming a second semiconductor opening region; s106, cleaning and etching are carried out, and a groove structure is at least formed in the second semiconductor opening region on the back surface of the silicon substrate; and S107, depositing a second semiconductor layer on the back surface, wherein the second semiconductor layer comprises an amorphous passivation layer and a second doped silicon layer. Under the conditions of simplifying the process steps and reducing the material cost, the interface contact resistance of the second semiconductor opening region can be reduced, the minority carrier lifetime is prolonged, and the cell efficiency and the double-sided rate are improved.

The invention belongs to but not limited to the technical field of new energy, particularly relates to a battery physical and chemical model parameter identification method and system based on different temperature impedances, aims to improve the accuracy of model simulation, considers contact resistance when establishing a one-dimensional P2D physical and chemical model of a battery, and simultaneously solves the problem that the model parameters are more and difficult to identify. In order to solve the problems that in the prior art, parameters with high sensitivity and medium sensitivity and meeting actual conditions are selected by adopting a parameter sensitivity analysis method, finally, the parameters selected under different working conditions are identified by adopting a grey wolf optimization algorithm, simulation EIS data are compared with actual measurement data, and the simulation accuracy of the model is influenced by excessive parameters. The result shows that the grey wolf optimization algorithm realizes accurate identification of the parameters of the one-dimensional P2D physical and chemical model of the battery. The method disclosed by the invention achieves remarkable results in the aspects of battery modeling and parameter identification.

The invention discloses a semiconductor device based on two-dimensional semi-metal interface optimized contact and a preparation method thereof, which are applied to devices including a two-dimensional semiconductor-based metal-semi contact structure, such as thin film transistors, Schottky junction diodes / transistors and the like. According to the invention, the two-dimensional semi-metal interface layer is introduced between the metal electrode (source and drain electrodes) and the two-dimensional material (conductive channel) through PVD and CVD processes, so that pollution and defects caused by additional transfer steps are avoided, preparation of the interface layer with large area, high uniformity and controllable thickness can be realized, and industrial requirements are met. According to the semiconductor device provided by the invention, the two-dimensional semimetal is introduced as the interface layer, so that the contact resistance between the source and drain electrodes and the conductive channel is obviously optimized, Fermi level pinning is eliminated, and the adjustable Schottky barrier height is realized; and a brand new solution is provided for development and industrial application of a metal-semiconductor contact structure device of a high-performance two-dimensional semiconductor.

The invention discloses an electric connector fault prediction method, and the method comprises the steps: synchronously obtaining multiple types of time series data of a contact area of a target electric connector in a preset time window based on a preset data collection device, and the time series data comprise temperature spatial and temporal distribution time series data, contact resistance transient time series data and a surface image sequence; performing feature analysis on the multi-source time sequence data by using a preset time sequence coupling sign extraction mechanism to obtain a multi-source phase change feature vector of the target electric connector in the current time window; inputting the multi-source phase change feature vector into a pre-trained electric connector health state prediction model, and outputting a prediction result of the health state of the target connector at the current moment, including a health state index; and performing differential early warning based on the predicted health state index of the target connector. Therefore, early and quantitative accurate prediction of the state of the electric connector is realized.

The invention relates to a method for preparing a carbon nanotube reinforced copper-silver-based electrical contact composite material based on a liquid phase atomization method, and belongs to the technical field of electrical contact preparation. The preparation method comprises the following steps: carrying out hot pressed sintering on mixed powder of reinforcement powder, copper powder and silver powder, solidifying the powder to form an Ag-coated CNTs / Cu-Ag composite material block, and then preparing the Ag-coated CNTs reinforced Cu-Ag-based electrical contact composite material through a process route of solid solution, extrusion and aging. The preparation method disclosed by the invention is simple to operate and stable in preparation process, and the mechanical and electrical properties of the prepared composite material can respectively reach 157HV and 103% IACS (International Annealed Copper Standard) and above; according to the method, ablation and damage of the surface of the electrical contact in the working process are relieved, the viscosity of a molten pool is increased, the contact resistance in the electrical contact process can be reduced, the current concentration phenomenon and the temperature rise effect at a contact point can be relieved, the mass loss of an electrical contact material is reduced, the maintenance cost is reduced, and the method has good application prospects in the field of electrical contact materials.

The invention provides a laser-induced sintering processing method which is applied to an 0BB double-sided electrode battery, a first electrode and a second electrode are adopted to make contact with all thin grid lines on the front face of a battery piece and all thin grid lines on the back face of the battery piece respectively, and a laser beam is controlled to scan the battery piece while reverse voltage is applied to the battery piece through the first electrode and the second electrode; the first electrode comprises N strip-shaped electrodes which are arranged at intervals; each strip-shaped electrode is vertically intersected and contacted with all the fine grid lines on the front surface of the battery piece; the width, needing to be scanned at a time, of the battery piece is divided into a plurality of areas, so that the distance between the strip-shaped electrode and the laser scanning area is shortened, the current density of each thin grid line is improved, the contact specific surface area of metal particles and silicon is increased, the contact resistance of the metal grid lines is reduced, and the service life of the battery piece is prolonged. Therefore, the purpose of high-efficiency laser-induced sintering of the 0BB double-sided electrode battery is achieved.

The invention discloses a temperature controller contact resistance fault monitoring and positioning method and system, and belongs to the technical field of contact resistance testing. According to the method, the corresponding initial database is constructed according to the models of different temperature controllers; performing low-energy-consumption real-time monitoring on the contact resistance in the temperature controller by adopting a resistance fluctuation threshold value monitoring method in combination with the initial database; when the fluctuation of the contact resistor is monitored, the infrared thermal imaging module is started to accurately determine the position information and the fault degree of the contact resistor according to a relative temperature difference method in combination with a resistance threshold fluctuation value.

The invention provides a solar cell and a preparation method thereof, and relates to the technical field of solar cells. The method for preparing the solar cell comprises the following steps: forming a tunneling oxide layer on one side of the back surface of a silicon substrate; forming a first intrinsic amorphous silicon layer, a first doped amorphous silicon layer and a second doped amorphous silicon layer; forming a second intrinsic amorphous silicon layer, a third doped amorphous silicon layer and a fourth doped amorphous silicon layer; performing annealing treatment on the silicon substrate to enable the first intrinsic amorphous silicon layer, the first doped amorphous silicon layer and the second doped amorphous silicon layer to form a first doped layer, enable the second intrinsic amorphous silicon layer, the third doped amorphous silicon layer and the fourth doped amorphous silicon layer to form a second doped layer, and enabling the first doped layer to point to the direction of the silicon substrate along the first doped layer, the concentration of the gallium element in the first doping layer is reduced; and the concentration of the boron element in the second doped layer is reduced. Therefore, the formed p-type doped polycrystalline silicon can achieve a good passivation effect, the concentration of the doping element B on the outer side is high, and the contact resistance can be reduced.

The invention relates to the technical field of batteries, in particular to a battery which comprises a positive plate, a negative plate and a diaphragm located between the positive plate and the negative plate, the diaphragm comprises a base material layer and a ceramic layer located on the surface of one side of the base material layer, a first polymer glue layer is arranged on the surface of the side, away from the base material layer, of the ceramic layer, and a second polymer glue layer is arranged on the surface of the side, away from the ceramic layer, of the base material layer. The diaphragm in the battery can provide certain binding force for the expansion of the silicon negative electrode, the contact resistance at an interface is reduced, the stress acting on the positive plate during the expansion of the silicon negative electrode is reduced, and the transmission rate of lithium ions in the battery is improved, so that the cycle performance and the safety performance of the battery are improved.

The invention belongs to the technical field of power equipment state monitoring, and discloses a cable branch box operation state intelligent evaluation system based on multi-sensor fusion, which comprises a state acquisition module used for acquiring a partial discharge signal, a voltage fluctuation signal, a terminal temperature signal and a terminal contact resistance signal of a cable branch box in an operation process, constructing a multi-source operation state parameter set of the cable branch box through time synchronization and physical quantity normalization processing; the mutual coupling analysis module is used for performing transient correlation deduction on the partial discharge signal and the corresponding voltage fluctuation signal based on the multi-source operation state parameter set to obtain a partial discharge-voltage coupling amount; when the partial discharge-voltage coupling amount exceeds a preset partial discharge-voltage coupling amount threshold value, determining that partial discharge abnormity caused by insulation degradation exists in the cable branch box; comprehensive and accurate evaluation of the operation state of the cable branch box is realized, and reliable support is provided for safe operation and maintenance of equipment.

The invention discloses a low contact resistance thin film transistor and a preparation method thereof, and the thin film transistor comprises a substrate; a gate electrode on the substrate; the gate dielectric layer is positioned on the gate electrode; the channel layer and the source and drain electrodes are located on the gate dielectric layer; the source electrode and the drain electrode are separated by the channel layer, and the channel particle layers are located between the source electrode and the drain electrode and the channel layer respectively. The metal oxide layer is formed on the contact interface of the channel layer and the source and drain electrodes of the thin film transistor, so that the contact resistance of the thin film transistor is greatly reduced.

A semiconductor device includes a stacked transistor structure having field effect transistors on two levels. The two levels include a top side and a bottom side. Active regions are disposed on the bottom side including a leveled surface facing the top side and a faceted backside surface opposite the leveled surface. The leveled surface includes two different semiconductor materials. A backside contact in contact with the faceted backside surface forms a wraparound contact to reduce contact resistance.

The invention relates to the technical field of nano-probe detection, and particularly discloses a nano-probe test system for feeding back contact force in real time, comprising the following modules: a probe execution module comprising a nano-probe and a piezoelectric ceramic driver, the nano-probe realizing three-dimensional micro-displacement and establishing controllable contact with a wafer; the multi-dimensional signal sensing module is used for synchronously acquiring a contact resistance signal and a nanoprobe deformation signal; the data processing and control module is used for realizing signal analysis, force value calculation and driving control of a contact resistance signal and a nanoprobe deformation signal; the man-machine interaction module comprises a touch display screen and a real-time data recorder and is used for realizing visualization of force signals; the data processing and control module carries out cooperative analysis on the contact resistance signal and the nanoprobe deformation signal obtained by the multi-dimensional signal sensing module to obtain the real-time contact force of the nanoprobe and the wafer. The system solves the problem that a traditional nanoprobe detection system cannot feed back the contact force in real time.

The invention relates to the technical field of electronic component testing for investigating or analyzing internal microstructures and physical properties of materials by utilizing an electrical means, and discloses an online testing and analyzing method for physical properties of electronic component materials, which comprises the following steps of: constructing a composite excitation signal formed by linearly superposing a main carrier voltage and a perturbation wave voltage; applying the signal to a to-be-tested electronic component and acquiring response current; and extracting an intermodulation current amplitude at an intermodulation frequency point in the frequency spectrum of which the linear response interval is excluded, calculating a nonlinear response coefficient of the material in combination with the excitation amplitude, and comparing the nonlinear response coefficient with a preset degradation threshold so as to judge whether the nonlinear response coefficient is qualified or not. By extracting intermodulation components which cannot be generated by linear contact resistance, physical isolation of external contact noise in a frequency domain is realized, and the problem that contact resistance fluctuation and material intrinsic aging cannot be distinguished in a traditional linear impedance test is solved.

The invention relates to a direct current motor with an anti-electromagnetic interference structure in the field of motors, which is characterized in that the surfaces of a commutator and an electric brush are blown in real time through a magnetic shielding cylinder arranged on the outer side of the commutator and an air blowing blade arranged in the magnetic shielding cylinder, and carbon powder on the surfaces of the commutator and the electric brush is cleaned; the commutator and the electric brush are subjected to synchronous blowing heat dissipation, so that the commutator and the electric brush have relatively good contact stability, the condition of contact resistance increase caused by carbon powder accumulation is reduced, the probability of arc generation between the commutator and the electric brush is reduced, and the electromagnetic compatibility of the motor is further improved; the influence of a high-frequency magnetic field generated by the arc on a rotor winding coil is reduced, and electromagnetic interference is further reduced; in addition, the insulating groove formed in the commutator improves the collecting and cleaning effects of the carbon powder, and the insulating groove is matched with the diversion disc to realize ejection of the lower contact surface of the electric brush, so that the cleaning effect of the carbon powder is further improved.