36 results about "Ac resistance" patented technology

The invention discloses a conducting wire state evaluation method and device based on current-carrying capacity, terminal equipment and a storage medium, and belongs to the field of conducting wires, and the method comprises the steps: determining the conducting wire radiation heat dissipation power, conducting wire convection heat dissipation power and conducting wire sunlight heat absorption power of a target conducting wire according to an environment parameter, a physical attribute parameter and a real-time operation parameter; calculating the theoretical current-carrying capacity of the target wire according to the nominal alternating-current resistance value in the physical attribute parameters, the calculated convection heat dissipation power of the wire, the calculated radiation heat dissipation power of the wire and the calculated sunlight heat absorption power of the wire; and according to the theoretical current-carrying capacity, the load current, the wire convection heat dissipation power, the wire radiation heat dissipation power and the wire sunlight heat absorption power, calibrating the nominal alternating current resistance value to obtain a calibrated alternating current resistance value, and calculating the calibrated current-carrying capacity so as to evaluate the operation state of the target wire. According to the invention, the problem of inaccurate lead state evaluation in the prior art can be solved.

The embodiment of the invention provides a cable alternating current resistance measuring system, method and equipment. The system comprises a power supply unit, a zero-phase closing switch unit, a transition loop unit, a to-be-measured cable and a cable measurement loop unit, and the zero-phase closing switch unit is connected with the transition loop unit and the cable measurement loop unit and used for controlling connection or disconnection between the transition loop unit or the cable measurement loop unit and the power supply unit. The power supply unit is connected with the zero-phase closing switch unit and is used for supplying power to the transition loop unit or the cable measurement loop unit, and the transition loop unit is connected with the zero-phase closing switch unit and is used for stably transitioning closing overvoltage generated by the power supply unit to preset voltage; and the cable measurement loop unit is connected with the zero-phase closing switch and the cable to be measured and is used for determining the alternating-current resistance of the cable to be measured. According to the technical scheme, the influence of switching-on overvoltage in a loop can be avoided, and the alternating-current resistance of the to-be-tested cable can be accurately obtained.

The application discloses a large-section conductor alternating current resistance automatic testing system and method, and relates to the electrical testing field.The system comprises a computer, an FPGA / real-time system, a D / A converter 1, a D / A converter 2, a D / A converter 3, an A / D converter, a voltage-controlled current source, electrodes, a GIL conductive pipe sample, a through-type high-precision current transformer, a high-precision resistor R, a lock-in amplifier and a coupling transformer with a load Z.The application eliminates the mutual inductance between a current loop and a voltage testing loop and the influence of the self-inductance of a sample, generates a 90-degree leading current voltage based on an equivalent circuit model through the FPGA and the D / A converter, and is used for compensating the voltage on the self-inductance of the sample and the mutual inductance in the voltage testing loop, reducing the phase angle between the voltage on the measured conductor and the exciting current, solving the precision problem of the large-section conductor alternating current resistance testing, and realizing the accurate and automatic measurement of the large-section conductor alternating current resistance.

The purpose of the present invention is to reduce AC resistance. In a multilayer substrate (100), a plurality of ground electrodes (41-44) are separated from each other in the thickness direction (D1) of a laminated substrate (1), and are adjacent to a plurality of signal lines (21-24) in the width direction of the plurality of signal lines (21-24). In a first transmission line region where the maximum line width of the plurality of signal lines (21-24) is minimum, the plurality of signal lines (21-24) do not overlap with any one of the plurality of ground electrodes (41-44) in the thickness direction (D1) of the laminated substrate (1). In a second transmission line region (102) in which the maximum line width of the plurality of signal lines (21-24) is the largest, one ground electrode (41) among the plurality of ground electrodes (41-44) overlaps with signal lines (22-24) other than the signal line (21) adjacent to the one ground electrode (41) among the plurality of signal lines (21-24).

The application discloses a kind of litz wire winding intelligent design optimization methods, and the litz wire winding ac resistance and porosity are obtained by neural network and hfss, the model of litz wire winding is constructed using hfss simulation software to simulate the ac resistance of litz wire winding under different materials, different number of turns, different litz wire winding radius and different frequency, to complete the training data and test data used to litz wire winding neural network model. Manual grid division is used to simplify the solving steps and time, and the accuracy is ensured. The litz wire winding neural network model is used to automatically train and test using particle swarm optimization algorithm to improve the network model, and finally the litz wire winding neural network model can quickly and accurately obtain the required litz wire winding ac resistance. The application can be used to quickly and accurately obtain the litz wire winding ac resistance under different requirements, reduce the amount of calculation and working time, greatly improve the efficiency.

The utility model discloses a special alternating current resistance box for detecting a conductivity meter, which relates to the technical field of alternating current resistance boxes and comprises a resistance box main body, wiring grooves are arranged on the back of the resistance box main body at equal intervals, a wiring mechanism is arranged on the outer side of the resistance box main body, and the wiring mechanism comprises a bearing assembly and a pressing assembly. The bearing assembly and the pressing assembly are used in cooperation, the bearing assembly comprises rotating shafts, the rotating shafts are symmetrically and rotatably connected to the outer side of the resistance box body, and rotating ends are fixedly connected to the outer sides of the two rotating shafts. According to the alternating-current resistance box special for detecting the conductivity meter, due to the arrangement of the ground wiring mechanism, it can be ensured that electric wires are arranged in the wire grooves of the bearing columns in order, the electric wires are kept stable and prevented from loosening or falling off through the tension of the tension springs, the situation that the electric wires are not attached due to the toughness of the electric wires is avoided, the structure is simple, and the practicability is high. And the practicability is high.

The application relates to a flat wire stator with multi-parallel winding, comprising a stator core and a flat wire winding, the stator core has a plurality of stator slots, the number of layers of the flat wire winding in the stator slots is ten, and the flat wire winding comprises a three-phase winding; the three-phase winding is three groups of parallel winding lines, each group of winding lines is five parallel branches, and each branch comprises a plurality of PIN wire conductors arranged in the stator slots and connected in series with each other. After the winding is divided into ten layers, the thickness direction size of each layer of conductors is relatively small, the increase of high-frequency alternating current resistance can be obviously inhibited, and the design of five parallel branches per phase makes the total current be uniformly shunted to the five branches, and the current borne by each branch is only 1 / 5 of the total current. This reduces the current stress of each PIN wire conductor, allows the use of a smaller cross-sectional area of the conductor, reduces the Joule heat concentration in the branch, and improves the motor temperature rise.

The application discloses a cable conductor AC resistance testing device and method, which directly supplies a large current to a cable conductor, measures the temperature, current and voltage of the powered cable conductor, adopts the measured data and a function relationship between the interference voltage value and the cable conductor radius which is fitted in advance, and obtains the cable conductor AC resistance, so that the reverse current is not applied to the cable metal shielding layer, and the proximity effect between the cable conductor and the shielding layer is avoided to influence the test result.

The invention discloses a method and a system for predicting coil parameters of a wireless power transmission system, and relates to the technical field of coil electrical parameter calculation, finite element simulation is performed based on an established two-dimensional parameterized geometric model of a circular coil to obtain training data, and the training data is used to train an improved Gaussian process regression model to obtain a prediction result. The method comprises the steps of obtaining a coil parameter prediction model, constructing an integrated learning correction model based on the coil parameter prediction model, predicting coil geometric parameters to be predicted based on the coil parameter prediction model and the integrated learning correction model, and obtaining coil electrical parameters including alternating-current resistance, self-inductance and mutual inductance. According to the method, the coil parameters under different working conditions are efficiently predicted, the time consumption of traditional finite element simulation is reduced, the accuracy of coil alternating current resistance, self inductance and mutual inductance obtained through prediction is more effectively ensured, and therefore the coil parameters of the wireless power transmission system are accurately and efficiently predicted.

An inductor has a main magnet core, a coil mounted around the main magnet core, and a residual magnet encapsulating the main magnet core and partially encapsulating the coil. The main magnet core is made of a main magnet core powder containing amorphous iron base material and nickel base material powders. The residual magnet is made of a residual magnet powder containing a main magnet powder and a soft magnet powder including an iron-silicon-chromium alloy powder and a carbonyl iron powder. Thus, through a low-loss feature of the amorphous iron base material and nickel base material powders, a loss of the main magnet core is reduced. Furthermore, a magnetic permeability of the residual magnet matches a magnetic permeability of the main magnet core. A magnetic leakage is further avoided, and the alternating current resistance is reduced. A quality factor and a conversion efficiency are enhanced.

This diagnosis device may comprise: a direct current device for discharging a battery cell with a fixed current for a predetermined measurement period so as to measure a direct current resistance of the battery cell; an alternating current device for supplying an alternating current to the battery cell so as to measure an alternating current resistance of the battery cell; a voltage measurement device for measuring a voltage of the battery cell; a memory for storing, for each of a plurality of diagnosis periods, each of a plurality of resistance pairs in which the direct current resistance and the alternating current resistance are matched; and a diagnosis control circuit for calculating the direct current resistance and the alternating current resistance according to the voltage of the battery cell for each of the plurality of diagnosis periods, acquiring a graph for the plurality of resistance pairs on the basis of a plurality of dots corresponding to the plurality of resistance pairs, and determining a normal resistance range based on the graph on the basis of the graph and the uppermost dot and the lowermost dot, among the plurality of dots, that are farthest from the graph.

The application provides a power ferrite material, a preparation method thereof and an automobile electronic product, and the power ferrite material is composed of a base material and an additive; the base material comprises, in terms of mole percentage, Fe2O3 52.95-53.25 mol%; MnO 36.55-37.05 mol%; and ZnO 9.7-10.5 mol%; and the additive comprises, in terms of total mass of the base material being 100%, CaCO3 0.13-0.18%; and Co2O3 0.2-0.33%. The composition of the power ferrite material is regulated, so that the alternating current resistance (ACR) value of the power ferrite material under the condition of 25 DEG C, 200 kHz and 0.5 V is reduced, and thus the UF40 product is facilitated to be applied in the automobile field.

The invention discloses an AC resistance analytical calculation method suitable for a double-layer orthogonal DD coil, and the method comprises the steps: firstly selecting the double-layer orthogonal DD coil, and determining a conduction effect correction coefficient and a proximity effect correction coefficient; then calculating conduction resistance and internal proximity resistance of the double-layer orthogonal DD coil; mirror image processing is carried out on the double-layer orthogonal DD coil, the double-layer orthogonal DD coil and a mirror image of the double-layer orthogonal DD coil are respectively divided into a plurality of long straight conductor sections, and each conductor section is further divided into a plurality of sub-sections; for each sub-segment, calculating the external magnetic field intensity, then calculating the external proximity effect resistance of the double-layer orthogonal DD coil sub-segment according to the external magnetic field intensity and a proximity effect correction coefficient, and summing to obtain the external proximity resistance; and finally, adding the conduction resistance, the internal adjacent resistance and the external adjacent resistance to obtain the total alternating-current resistance of the double-layer orthogonal DD coil, so that the alternating-current resistance of the double-layer orthogonal DD coil can be quickly and effectively calculated.

The invention provides a cable alternating current resistance measuring method and device and electronic equipment, and relates to the technical field of electric power measurement. The method comprises the steps that a current sampling signal and a voltage sampling signal of a cable are obtained, the current sampling signal is obtained by connecting a sampling resistor in series on the secondary side of a current transformer and measuring the voltage drop of the sampling resistor, and the voltage sampling signal is obtained by symmetrically arranging sampling points at the two ends of the cable and synchronously collecting the two ends; converting the current sampling signal and the voltage sampling signal into digital signal flows, wherein the digital signal flows comprise a current signal flow and a voltage signal flow; the digital signal flow is input into a trapezoidal integral resistance calculation model, the alternating current resistance of the cable is obtained, and the trapezoidal integral resistance calculation model is a model which is constructed based on a trapezoidal integral method and used for calculating the alternating current resistance based on the current signal flow and the voltage signal flow in the digital signal flow. According to the invention, the measurement accuracy and flexibility of the cable AC resistance are improved.

The embodiment of the invention provides a large-section cable actual AC resistance measurement method and device, a medium and a product. The method comprises the following steps: determining the total inductance in an actual alternating current resistance measurement loop through a pre-experiment; according to the total inductance, determining a compensation capacitor connected to the actual AC resistance measurement loop; adjusting the compensation capacitor through a phase difference constraint mechanism and a power supply maximum power constraint mechanism to obtain an adjusted compensation capacitor; and when the adjusted compensation capacitance enables the phase difference between the voltage and the current on the large-section cable to be within an allowable phase deviation threshold range, measuring the actual alternating-current resistance of the large-section cable by adopting a voltage and current phase method to obtain the actual alternating-current resistance. The method is used for achieving the effect of accurately measuring the actual alternating-current resistance of the large-section cable.

The invention relates to the technical field of wireless power transmission, and discloses a low-loss PCB Litz planar spiral coil and a design method thereof. According to the coil, through a three-dimensional magnetic field balance layout of region division, multi-strand parallel connection (N), circumferential segmentation (M) and interlayer rotation (theta), homogenization of current in the thickness direction and the circumferential direction is achieved, and skin and proximity effects are remarkably inhibited. The AC loss is reduced, and the quality factor is improved. The design method comprises the steps of S1, coupling coefficient optimization; s2, optimizing magnetic loss; s3, selecting the number of strands and the number of segments of a conductor; and S4, performance verification. An example shows that under the working frequency of 150 kHz, compared with a traditional PCB coil, the alternating current resistance of the structure is lower, the quality factor is higher, and the coil is suitable for a compact high-performance wireless power transmission system.

The aim is to reduce AC resistance. In the AC signal line (2) of the multilayer substrate (100), multiple signal lines (21-23) are electrically connected by multiple connecting conductors that pass through one of multiple insulating layers (11-13) in the thickness direction (D1) of the multilayer substrate (1). The multiple signal lines (21-23) include a first signal line (21) that is closest to the first main surface (101) of the multilayer substrate (1) in the thickness direction (D1), a second signal line (23) that is closest to the second main surface (102) of the multilayer substrate (1) in the thickness direction (D1), and a third signal line (22) that is located between the first signal line (21) and the second signal line (23) in the thickness direction (D1) of the multilayer substrate (1). In the thickness direction (D1) of the laminated substrate (1), at least one of the thickness (T21) of the first signal line (21) and the thickness (T23) of the second signal line (23) is thicker than the thickness (T22) of the third signal line (22).

The objective of the present invention is to provide a structurally stable power cable capable of assuring a high but acceptable current during alternating current transmission by minimizing alternating current resistance by suppressing the skin effect. In addition, according to the power cable of the present invention, a reinforcing string is embedded in a central insulator to assure structural stability of the power cable by preventing problems such as breakage and shrinkage of the central insulator in manufacturing and use environments of the power cable.

The utility model provides a high-frequency high-power resonance inductor which comprises a shell and a magnetic core arranged in the shell, the magnetic core is arranged in the shell in a potting mode, the magnetic core comprises an upper E-shaped core and a lower E-shaped core matched with the upper E-shaped core, a plurality of clamping grooves are formed in the lower end of the upper E-shaped core, and the lower E-shaped core is arranged in the clamping grooves. A plurality of clamping grooves are formed in the upper end of the upper E-shaped core, a plurality of protrusions corresponding to the clamping grooves are arranged at the upper end of the lower E-shaped core, the upper E-shaped core and the lower E-shaped core are arranged in a matched mode through the protrusions and the clamping grooves, a coil is wound in an area defined by the upper E-shaped core and the lower E-shaped core, the coil is wound by a plurality of stranded wires, and the outer side of the shell is wrapped by a nanocrystalline magnetic shielding layer. The utility model has the beneficial effects that the upper E-shaped core and the lower E-shaped core are matched with each other, so that the magnetic core is convenient to mount and dismount, and the heat dissipation is convenient; a ferrite and amorphous alloy composite magnetic core is adopted, the high-frequency eddy current loss is reduced, meanwhile, the anti-saturation capacity is improved, the coil is formed by winding stranded wires, the alternating-current resistance can be reduced, and the skin effect can be reduced.

The invention belongs to the technical field of electromagnetic modeling and insulating property evaluation of a large generator, and provides a broadband circuit network modeling method of a stator winding in a running state of the large generator, which comprises the following steps: firstly, forming a slot part domain and an end part domain by stator winding according to electromagnetic field distribution characteristics, and respectively constructing a two-dimensional model and a three-dimensional model; based on a related physical relationship, capacitance and inductance with broadband characteristics and alternating current resistance parameters considering skin and proximity effects are extracted; then connecting the bar micro-segments in series by a pi-shaped equivalent circuit, connecting a plurality of bars in parallel in a practical series-parallel connection mode, and forming a distributed broadband equivalent circuit by mutual capacitance and mutual inductance in the same groove; and finally, an electromotive force instantaneous value is calculated according to rated parameters of the generator, a matched controlled voltage source is embedded in a series branch of the pi-type circuit, and a broadband equivalent circuit network model is constructed. The method can solve the problems that domain division is unreasonable, parameter accuracy is insufficient, and real operation working conditions cannot be fitted, and achieves the balance between modeling efficiency and simulation accuracy.

The embodiment of the invention provides a cable test section temperature control method, device and equipment, a medium and a product. The method comprises the steps of obtaining physical parameters of a cable test section and thermal resistance parameters of a thermal insulation material, performing calculation in combination with a thermal resistance formula to obtain target size parameters, arranging a thermal insulation layer conforming to the target size outside the cable test section, and dynamically adjusting the size of the thermal insulation layer according to temperature distribution of the test section. Through the mode, the heat dissipation path of the cable test section is balanced, the fringe effect is eliminated, uniform temperature distribution is ensured, the accuracy and engineering applicability of the cable alternating current resistance test are remarkably improved, and a reliable basis is provided for cable current-carrying capacity evaluation.

The invention relates to the technical field of electrical property testing of thermoelectric materials, in particular to a bismuth telluride crystal bar conductivity testing device. According to the invention, an integrated system of a support structure, a double-guide rail assembly, a perforated slide block assembly, a probe unit and high-precision AC resistance test equipment is constructed, wherein the support structure provides a bearing basis; the double-guide-rail assembly guides the bismuth telluride crystal bars to be axially positioned, and the hole opening sliding block assembly is slidably locked to achieve rapid adaptation to the bismuth telluride crystal bars with different lengths within 10 seconds. Spring probes of the probe unit form a four-wire method test loop, a semiconductor polarization effect is eliminated in combination with a high-frequency alternating current test signal, and the spring probes are in elastic contact to ensure that the signal is stable; and by matching with high-precision resistance testing equipment, resistance acquisition and conductivity calculation are completed. According to the invention, the problems of low efficiency, poor precision and complex operation of a traditional mode are solved, rapid and accurate measurement of the conductivity of the bismuth telluride crystal bar is realized, and an efficient testing tool is provided for research, development and production of thermoelectric materials.

1. Name of the designed product: AC resistance box for calibrating conductivity meter (ZX123B). 2. Use of the designed product: AC resistance box for calibrating conductivity meter. 3. Design points of the designed product: combination of shape and pattern. 4. Picture or photo that best indicates the design points: perspective view.

1. The name of the design product: intermediate frequency AC resistance welding controller (SVF1-1000DS). 2. The use of the design product: the design product is used in resistance welding industry. 3. The design points of the design product: in shape. 4. The picture or photo that best indicates the design points: perspective view.

The application discloses an alternating current resistance analytical calculation method suitable for a double-layer orthogonal DD coil. Firstly, a double-layer orthogonal DD coil is selected to determine a conduction effect correction coefficient and a proximity effect correction coefficient; then, conduction resistance and internal proximity resistance of the double-layer orthogonal DD coil are calculated; the double-layer orthogonal DD coil is subjected to mirror image processing, and the double-layer orthogonal DD coil and the mirror image thereof are respectively divided into a plurality of long straight conductor segments, and each conductor segment is further divided into a plurality of sub-segments; for each sub-segment, external magnetic field intensity is calculated, then external proximity effect resistance of the double-layer orthogonal DD coil sub-segment is calculated according to the external magnetic field intensity and the proximity effect correction coefficient, and is summed to external proximity resistance; finally, the conduction resistance, the internal proximity resistance and the external proximity resistance are added to obtain total alternating current resistance of the double-layer orthogonal DD coil. The application can quickly and effectively calculate alternating current resistance of the double-layer orthogonal DD coil.

The application provides a high-current low-wind-pressure overhead insulated cable, which comprises a conductor, a conductor shielding layer and an outer insulation layer arranged in sequence from inside to outside; the outer insulation layer comprises an annular body and a plurality of convex portions uniformly and spacedly distributed along the outer periphery of the annular body, and a concave portion is formed between two adjacent convex portions; the convex portion is T-shaped, comprising an outer arc segment, the end of the outer arc segment is connected with the annular body through an upper arc segment and a lower arc segment, and the upper arc segment and the lower arc segment are connected in an S shape. The application also provides a preparation method of the aforementioned overhead insulated cable. The application has the advantages that the insulation isolation of the central conductor and the outer layer conductor is arranged, and the T-shaped convex portion structure design of the surface of the outer insulation layer reduces the conductor AC resistance and the wind resistance coefficient, improves the heat dissipation efficiency, and realizes the beneficial effects of the current-carrying capacity improvement, the wind load reduction, the probability reduction of external force damage and the like.

The invention provides a measurement system of a TEC device and a method for measuring ACR, the measurement system comprises a current detection circuit and a driving circuit, the driving circuit comprises a micro-control unit and a TEC controller, the TEC controller generates an excitation voltage pulse based on a driving signal, the voltage under a first pulse of the excitation voltage pulse is a forward voltage, and the voltage under a second pulse of the excitation voltage pulse is a reverse voltage. The voltage under the second pulse is negative voltage; the current detection circuit generates a first sampling signal based on the first pulse and generates a second sampling signal based on the second pulse; the micro-control unit obtains a first working current according to the first sampling signal, obtains a second working current according to the second sampling signal, and obtains the AC resistance of the TEC device based on the positive voltage, the negative voltage, the first working current and the second working current. According to the invention, an LCR tester is not needed, and AC resistance measurement is completed by multiplexing an existing drive circuit and combining excitation voltage pulse and DC check calculation.

The invention provides a method and a system for measuring the longitudinal conductivity of a thin-layer material. The method for measuring the longitudinal conductivity of the thin-layer material comprises the following steps: fixing the thin-layer material to be measured; measuring direct-current resistance and alternating-current resistance of the thin-layer material to be measured; under the condition that the difference value between the direct-current resistance and the alternating-current resistance is smaller than or equal to a resistance difference value threshold value, the conductivity of the thin-layer material to be measured is determined according to the direct-current resistance and / or the alternating-current resistance; under the condition that the difference value between the direct-current resistor and the alternating-current resistor is larger than the resistance difference value threshold value, the thin-layer material to be measured is fixed again. The direct-current resistance and the alternating-current resistance of the to-be-measured thin-layer material are measured respectively, and verification is formed between the two resistance. In this way, it can be ensured that the data basis for calculating the conductivity has reliability, and therefore the accuracy of the longitudinal conductivity measurement result of the thin-layer material can be improved.

The invention provides a transformer multi-source loss prediction method considering inter-harmonic excitation and a foil winding structure, and belongs to the technical field of transformer multi-source loss prediction. Performing fast Fourier transform spectrum decomposition and time domain reconstruction on the inter-harmonic signal to obtain a frequency component set, constructing a foil winding frequency response function, and combining the foil winding frequency response function with structural parameters to establish a frequency mapping table to estimate multi-band eddy current loss; calculating the alternating current resistance of each layer of conductor based on a Dowell theory improved model of frequency division, introducing a proximity effect correction factor, carrying out itemized superposition on the core loss value of each frequency component and the alternating current resistance value of each layer, outputting the total loss value of the transformer, and adjusting a frequency response function parameter according to an eddy current distribution matrix; the technical problem that the multi-source loss prediction precision of the foil winding structure of the three-dimensional wound core transformer is insufficient under the inter-harmonic excitation condition is solved.