91 results about "Mutual impedance" patented technology

An apparatus for calculating immunity from a radiated electromagnetic field which makes possible high-speed simulation of the electric current flowing through an electronic apparatus due to a radio wave radiated from an antenna, and a method and a storage medium storing programs used for the same which divides a radio wave radiated from an antenna into a carrier wave, upper sideband wave, and lower sideband wave, and uses the moment method to simulate the effect of the radio wave on an electronic apparatus by calculating the mutual impedance for one frequency component out of the above three frequency components and using that mutual impedance to solve the simultaneous equations under the moment method so as to calculate the electric current flowing through the electronic apparatus.

A high gain built-in antenna for a radio communication terminal with less influence from the human body. This built-in antenna for a radio communication terminal includes bar-shaped second passive element 392 facing antenna elements making up dipole antenna 321. The distance between this second passive element 392 and the antenna elements making up dipole antenna 321 is appropriately set in such a way as to widen the band of the input impedance characteristic by changing mutual impedance between second passive element 392 and the antenna elements making up dipole antenna 321.

The invention provides a layout optimizing method for phased-array antennas on a large-scale ship plane, which includes the following steps: 1) setting two array antennas on the ship plane as an emitting array antenna and an interfered array antenna, and solving a port current of the emitting array antenna; 2) solving the port current of the interfered array antenna according to the port current of the emitting array antenna and mutual-impedance matrix between the array antennas; 3) measuring cross coupling between the array antennas by isolation, defining as shown, setting the Pr as emittingpower of the emitting array antenna and the Ps as receiving power of the interfered array antenna; 4) disposing the emitting array antenna and the interfered array antenna at different positions, changing beam direction (azimuthal angle and pitch angle) of the emitting array antenna so as to obtain a curve of isolation changing along with the beam direction, comparing the values of the isolation obtained at different positions, and selecting the positions with low isolation in all directions as the optimum layout of the array antennas.

The present invention relates to a harmonic source positioning and harmonic responsibility division method applied to an active distribution network. The main technical feature is that the method comprises a step of collecting the voltage and current of a common coupling point, a step of drawing the time-domain curve of an equivalent impedance and obtaining a harmonic source location, a step of obtaining the data needed by a harmonic impedance, and a step of calculating the harmonic mutual impedance between a concerned bus and each harmonic source and dividing harmonic responsibilities. The design of the method is reasonable, through establishing a load time-domain equivalent model, by using the physical relation of the voltage and current on a common coupling point, a parameter identification method is used to position the harmonic source in the active distribution network, through analyzing the bus harmonic voltage acted by all harmonic sources in the active distribution network and calculating the harmonic mutual impedance between the bus and the node where the harmonic source is to recognize the contribution of each harmonic source, and thereby a harmonic contribution standard measure is used to divide the responsibility of each harmonic source.

The invention discloses an online transient safety stabilization evaluation method based on automatic expected fault set filtering and belongs to the electric power system safety stabilization analysis technology field. According to the method, a participation factor of a node active power for transient power angle stabilization is calculated based on a transient power angle stabilization participation factor of a generator and mutual impedance between a node and a generator inner node, weak node voltage sensitivity of a node reactive power for transient voltage safety stabilization is taken as a participation factor for transient voltage safety stabilization, a participation factor of the node active power for transient frequency safety is calculated based on mutual impedance between the node and a transient frequency safety weak node, a transient safety stabilization quantification evaluation result is estimated based on a previous transient safety stabilization quantification evaluation result and present node power injection change, an estimation parameter is corrected through a posteriori correction method according to the transient safety stabilization quantification evaluation result based on time domain simulation and difference of estimated values. The method is advantaged in that automatic expected fault set filtering of online transient safety stabilization evaluation can be realized.

There is provided a novel method and circuit of compensating for cross-talk between pairs of adjacent array elements of a transceiver phased array and double-tuned transceiver arrays for a magnetic resonance system using a resonant inductive decoupling circuit. The geometry and size of the resonant inductive decoupling circuit allows for the decoupling circuit to compensate for the cross-talk between array elements, including the reactive and resistive components of the mutual impedance while being sufficiently small to not distort a RF magnetic field of the array elements produced within a sample.

The invention discloses a method for measuring phase to phase mutual impedance of a long-distance extra-high voltage common-tower double-circuit transmission line. The method comprises the first step that the head end of a measured phase is in an open circuit, the tail end of the measured phase is in ground connection, the head ends of other phases are in an open circuit, the tail ends of other phases are in ground connection, voltages are applied to the head end of the measured phase, currents are injected into the head end of the measured phase, and the current signal of the head end of the measured phase and the induction voltage signals of the head ends of other phases under two frequencies are synchronously measured; the second step that the voltage signals and the current signals under the two frequencies are obtained through an FFT filtering algorithm; the third step that phase to phase mutual impedance values under the two frequencies are respectively calculated according to the voltage signals and the current signals under the two frequencies, and a phase to phase mutual impedance value under the frequency of 50Hz is obtained by averaging the two phase to phase mutual impedance values. According to the method, a traditional measurement method is changed, the influence of line distribution parameter characteristics and induction voltage phases and the existence of power frequency interference are considered in the line connection mode and the algorithm, and especially in the long-distance transmission line, the errors of the phase to phase mutual impedance value measured through the method are reduced, and engineering needs are met.

The invention relates to an RFID (radiofrequency identification) tag applied to intensive distribution scenarios and a mutual impedance design method thereof. The RFID tag designed comprises a dielectric substrate, a metal microstrip antenna and a chip; the metal microstrip antenna and the chip are arranged on the dielectric substrate. The metal microstrip antenna is composed of a pair of radiation patches, a pair of bent radiation arms and a resonant matching ring. The radiation patches are in a rectangular shape. The bent radiation arms are in an M shape; 10 folds are made on each side of the bent radiation arms. The resonant matching ring is U shaped; two vertical arms of the resonant matching ring are connected with a feeder; the feeder is welded to an anode and a cathode of the chip and connected in a single-port manner. By the use of the mutual impedance design method to the RFID tags, mutual coupling of RFID tags is decreased. The RFID tag has a maximum transmission coefficient 0.8, a maximum gain 2.28dbi and a longest reading distance 10m under operating frequencies; the RFID tag has a wider range of coverage. Under the frequency 920MHz, the RFID tags spaced by 2mm generate mutual impedance less than 50ohm; a good capacity to recognize multiple RFID tags is provided.

A dual band antenna device includes a first antenna unit which includes a first long element, a first short element whose resonant frequency is different from the resonant frequency of the first long element, a first frequency adjustment element provided in the first long element to adjust the resonant frequency, and a first power feeding port that is a power feeding end; a second antenna unit which includes a second long element, a second short element whose resonant frequency is different from the resonant frequency of the second long element, a second frequency adjustment element provided in the second long element to adjust the resonant frequency, and a second power feeding port that is a power feeding end; and a coupling element which connects the first antenna unit and the second antenna unit while adjusting a mutual impedance between the first antenna unit and a second antenna unit.

The invention discloses a mutual coupling compensation analysis method for a microstrip array antenna. The method comprises the following steps of: modeling an array antenna structure, and performing delaunay triangulation on the structure by using the delaunay of a MATLAB function to divide the surface of a metal to be researched into a series of triangles, wherein each pair of triangles with common sides forms corresponding Rao-Wilton-Glisson (RWG) side elements; and replacing the surface current distribution of the RWG side elements of two triangles by using an infinitesimal dipole with an equivalent dipole moment or strength by adopting a dipole modeling method, and determining the electromagnetic radiation characteristics of a free space for surface current. A mutual impedance array, solved by adopting a moment method, of the microstrip array antenna takes the effect of mutual coupling between adjacent radiation elements into account. Therefore, a mutual coupling weight vector of an array unit is corrected during weight vector calculation mutual coupling effect correction to further optimize the output direction characteristics of an array.

The invention discloses a uniform circular array direction-finder antenna receiving mutual impedance test and a mutual coupling compensation system. A method for achieving the system comprises receiving a mutual impedance model building unit, obtaining an antenna port voltage unit under array element mutual coupling, obtaining an antenna port voltage unit under non-array-element mutual coupling, building a mutual coupling voltage array unit, building a mutual coupling current array unit and building a uniform circular array receiving mutual impedance array unit. The uniform circular array direction-finder antenna receiving mutual impedance test obtains all antenna port voltage under array element mutual coupling effects and antenna port voltage after removing the mutual coupling effects by setting one horizontal wave incoming direction, and a uniform circular array receiving mutual impedance array is built according to a receiving mutual impedance theory. When direction-finding equipment works, the uniform circular array receiving mutual impedance array conducts mutual coupling compensation on a direction-finder terminal processing machine while meeting work frequency points, and accordingly direction showing degree output by the direction-finding equipment is accurate.

The invention discloses an accurate fault locating method for double circuit lines on the same pole, which is used for solving the problems of locating errors caused by unavailability of avoiding mutual impedance and mutual susceptance phase difference among leads and the realization of fault location in any fault existing in the conventional fault locating method for double circuit lines on the same pole. According to the accurate fault locating method, an accurate fault calculation method is adopted. The accurate fault locating method comprises the following steps of: 1, calculating measured values of current and voltage vectors before and after a fault with a Fourier algorithm; 2, calculating impedance matrixes and potentials of systems on both sides; 3, calculating to obtain a transfer matrix ranging from fault points of the double circuit lines on the same pole to a bus by using different fault distance values with a feature modulus decomposition method; 4, constructing a resistance matrix of the fault points by using different fault resistance values; 5, solving an equation to obtain calculated values of voltage vectors of buses on both sides and current vectors from a circuit to a bus; and 6, calculating an error quadratic sum of each vector calculated value and measured value. In different values of a fault distance and fault resistance, the error quadratic sum calculated by using a fault distance and a fault resistance value which are most proximate to a practical fault distance and practical fault resistance in the step 6 is least.

A method for wireless power transmission includes establishing respective wireless communication link between a coordinating transmitter and each receiver. The method further includes measuring respective mutual impedance between a coordinating transmitter and each receiver by applying a voltage to the coordinating transmitter and configuring each receiver to measure an induced current in response to the applied voltage. The method calculates respective matching impedance for the coordinating transmitter and each receiver based on corresponding mutual impedance. The method transmits the respective matching impedance to each receiver to enable each receiver to adjust to have the respective matching impedance. The method adjusts the coordinating transmitter to have the respective matching impedance.

The invention discloses a short-circuit current limiter additionally-arranging method which comprises the steps of: presetting an upper limit of the number of current limiters, a theoretical current-limiting target and the number of current additionally-arranging current limiters; scanning short circuit current; determining nodes needing limiting; calculating mutual impedance values of the nodes; carrying out particle swarm optimization to obtain corresponding selected node sequences; configuring the current limiters according to the selected node sequences; re-scanning the short circuit current; calculating an actual current-limiting target, if the actual current-limiting target is within a range of the theoretical current-limiting target, ending; if the actual current-limiting target is not within the range of the theoretical current-limiting target and the number of the arranged current limiter does not exceed the upper limit, adding 1 and continuously carrying out particle swarm optimization; and if the actual current-limiting target is not within the range of the theoretical current-limiting target and the number of the arranged current limiter exceeds the upper limit, ending. The invention also discloses a configuring device. A global optimum additionally-arranging configuration point of a short circuit current limiter can be rapidly and accurately found.

The invention provides an external network equivalence method for an electric power system applicable to subsynchronous resonance, belonging to the technical field of the electric power system. The method comprises the following steps: retaining a plurality of units and series compensation transmission circuits of the electric power system to obtain a primary range of external network equivalence, and an equivalent boundary point; obtaining equivalent impedance after an equivalent boundary point; simplifying mutual impedance branches among a plurality of equivalent boundary points; obtaining an equivalent power parameter of the external network; obtaining the system subsynchronous frequency impedance which is Z1(f) by seeing from the units to a network side in the primary range of external equivalence; expanding a plurality of scales to obtain a system subsynchronous frequency impedance which is Z2(f) by seeing from the units to the network side in a new range of the external network; and determining whether to expand equivalent scales or not by judging the Z1(f) and the Z2(f) so as to obtain an external equivalent result. The method can improve the accuracy of the subsynchronous resonance result, and has important engineering application value in formulation of SSR control strategy and safe and stable operation of the system.

An embodiment of the invention discloses an antenna signal tuning device of a terminal as well as the terminal and relates to the field of communication. The antenna device can be arranged outside or inside, the radio frequency performance of the terminal is improved, and performance compatibility of the antenna in different states is improved. A single-frequency rod antenna body is connected with a circuit board of the terminal through a first feed point and used for transmitting a wireless signal which is tuned by a coupling branch and has a target frequency point when the single-frequency rod antenna body is in different states. The coupling branch is connected with the circuit board of the terminal through a second feed point and used for tuning actual impedance values of the single-frequency rod antenna body in different states according to impedance values of the single-frequency rod antenna body in different states and a mutual impedance value of the coupling branch for the single-frequency rod antenna body. Accordingly, the frequency deviation problem of a single-frequency rod antenna in different states is solved.

The invention discloses a start-up method of a receiving terminal power grid for enabling the DC feed-in. The method comprises the steps of screening out priority on-off lines according to a grid structure and a power flow result of a receiving terminal power grid; turning on and off the priority on-off lines one by one and calculating the vulnerability indexes of each priority on-off line; according to the vulnerability indexes, constructing an on-off line fault set; calculating the temporary drop index of a bus voltage during each on-off line fault in the on-off line fault set; according tothe temporary drop index of the bus voltage, constructing a voltage weak bus node set; representing the electrical distance between each unit and each bus node in the voltage weak bus node set throughthe mutual impedance of the node; ranking the voltage supporting capacities of all units according to the electrical distance; and checking the ranking result of the voltage supporting capacities.

In Moment method, by regarding the current values of a wave source to be constants, the simultaneous equations of the wave source and the simultaneous equations of a receiving object can be separated and the current values of the wave source and the current values of the object can be separately calculated. Even if the positional relationship between the wave source and object changes, the mutual impedance between the elements of the object does not change. Therefore, there is no need to calculate the coefficient matrix of the simultaneous equations of the object again.

The invention discloses a method and a system for evaluating the adaptability of an AC / DC power network to the restoration of a DC system, When the DC system starts, the voltage and frequency safety of the AC system are evaluated according to the active power, reactive power, short-circuit capacity of the DC converter bus and the frequency modulation ability of the AC system when the DC system starts. The static voltage stability of multi-infeed DC system is checked by using multi-infeed generalized short-circuit ratio when the DC system power rises to the rated value after the DC system starts up to meet the safety conditions. The static voltage stability of multi-infeed DC system is checked by using multi-feed generalized short-circuit ratio. After the static voltage stability of multi-feed HVDC system is restored, the risk of commutation failure in the restored HVDC system is evaluated by using the relationship between electrical parameters and mutual impedance. The invention ensures the technical safety of the multi-infeed DC system in restoring the early start-up DC system, and can make full use of the DC regulating ability and accelerate the process of system restoration.

A method for accurately predicting near-field electromagnetic compatibility of array antennas comprises the following steps: (1) according to mutual impedance matrix, solving array element coupling and superposition between two planar array antennas; (2) calculating the port excitation voltage of the transmitting array antenna according to the transmitting power of the transmitting array antenna,and calculating the port excitation voltage of the interfered array antenna according to the response current of the port of the interfered array antenna and the internal resistance of the interferedarray antenna; (3) according to the surface current and port current of the antenna array, calculating the impedance of the two antennas array, and finally predicting the isolation between the two antennas array. The method accurately predicts coupling and interference between array antennas, and is especially suitable for accurate prediction of electromagnetic compatibility between planar array antennas on ships. Compared with the conventional uniform diffraction theory, the theory of the invention remarkably improves prediction accuracy of final isolation result.

A parallel multi-loop power transmission line zero sequence parameter positive sequence on-line testing method is disclosed and belongs to the field of parallel multi-loop line coupling parameter testing. According to the method, steady-state data is used for testing positive sequence impedance and admittance of a loop line being tested, a ratio of impedance of parallel multi-loop lines and a ratio of admittance of the parallel multi-loop lines are calculated in the same environment, own impedance (own admittance) Z<->ii and mutual impedance (mutual admittance) Z<->ij are estimated and are finally presented in a formula defined in the description, errors can be effectively suppressed, and zero sequence coupled impedance and admittance of the parallel multi-loop power transmission lines can be tested indirectly on line. Via use of the testing method put forward in the invention, special-purpose zero sequence operation is not required, normal system operation cannot be affected, specifically effects exerted on an impedance testing method by soil resistivity is taken into account, fault tolerance capability and anti-interference capability of the method can be guaranteed, a parallel multi-loop power transmission line parameter testing method can be simplified, and testing efficiency, flexibility and operability can be improved.

The invention relates to test methods of mutual impedance and coupling capacitance of transmission lines in parallel. The test method of mutual impedance comprises the following steps that: a head end of one phase test line in a test line accesses a pilot frequency testing voltage and the end of the phase test line is grounded; the head end voltage, the head end current and the end current of the phase test line are tested and a voltage power frequency component and a current pilot frequency component are calculated; a head end voltage and a head end current of one phase operation line in an operation line are tested and a voltage pilot frequency component and a current power frequency component are calculated; and according to the current pilot frequency component and the voltage pilot frequency component, the mutual impedance between the phase test line and the phase operation line is calculated. According to the test methods provided by the invention, mutual impedance and coupling capacitance of transmission lines in parallel can be accurately tested under the circumstances that the lines are operated and there is no power failure, thereby improving test efficiency and accuracy.

The invention relates to a visual measurement method for temperature distribution of a single-connection combustion field. The visual measurement method comprises the following specific operation steps: 1, acquiring local admittance and temperature data of flame by using an ionic current probe and a thermocouple probe aiming at the typical working condition of a combustor; 2, establishing a mapping model from the admittance rate of the combustion field to the temperature by utilizing the measurement data; 3, designing an electrical tomography sensor according to the structure of the combustor,measuring the mutual impedance of the electrode array distributed around the combustion field, and reconstructing the distribution of the conductivity and the dielectric constant in the combustion field; and 4, substituting the reconstructed distribution data into an admittance-to-temperature mapping model to obtain a temperature distribution image. The method provided by the invention is suitable for measuring the combustion field with a lightproof structure and can quickly obtain the image of temperature distribution and has the advantages of no contact, no radiation, simple structure, lowcost and the like and has important practical value and application prospect.

The invention, which belongs to the technical field of operation control of the power system, relates to a linearized power flow calculation method for a radial distribution network. On the basis of the traditional linear equation without considering the network loss and the interphase mutual impedance, linear expansion of the nonlinear network loss item is included by the equation and a linearized three-phase branch power flow equation is established; with active power loads and reactive power loads of all nodes, similar values of active powers and reactive powers of all branches and all nodevoltages are calculated to obtain a power flow calculation result of the radial distribution network. According to the invention, compared with the linearized branch flow equation without consideringthe network loss, the provided equation enables the computing precision to be improved substantially; an approximate solution of the power flow can be obtained directly without iterative solution, sothat computing is done quickly. The linearized power flow calculation method is suitable for the scene with strict performance requirements on the real-time online analysis of the distribution network.

The invention relates to a distribution network sensitivity calculating method based on a linearized power flow, and belongs to the technical field of power system operation control. On the basis of the conventional linear equation without considering the network loss and interphase mutual impedance, a nonlinear network loss item is linearly expanded and contained in the equation, and a linearizedpower flow equation of a three-phase branch circuit is established. According to variations of active power and reactive power of all nodes, the variations of the active power and the reactive powerof the branch circuit and variation of node voltage are calculated so as to obtain the sensitivity of the branch circuit power and the node voltage relative to node injection. Compared with the powerflow equation without considering the network loss, the distribution network sensitivity calculating method provided by the invention has the advantages as follows: the calculation accuracy is improved and the calculation is rapid; the distribution network sensitivity calculating method is applicable to real-time online analysis of a distribution network and other scenes.

This invention relates to a light transmission system especially to the application of an accessed analog signal transmission system, which requires providing 2-way broadband analog signal transmission, and this invention is a 2-way broadband analog signal transmission module of low cost and small volume utilizing a non-refrigeration laser to reduce the cost by using mutual impedance analog pre-amplification receiving circuit to get high bandwidth analog transmission bandwidth and using a small dual-fiber 2-way or single-fiber 2-way light devices to reduce volume of light transmission module, in the analog transmission in optical modules, it firstly applies a plug structure to meet the flexible configuration of the analog transmission system in application.

The invention discloses a rapid positioning method for the non-power frequency current causing voltage distortion of a converter bus. The method mainly comprises steps that (1), the system topology and device parameter information is obtained; (2), a system broadband admittance matrix model is established, and a system broadband impedance matrix model is solved; (3), the frequency scanning methodis utilized to calculate to obtain broadband mutual impedance of a non-power frequency current injection node and a converter station bus node; (4), the broadband mutual impedance information of the non-power frequency current injection node and the converter station bus node is screened and stored; and (5), influence of non-power frequency current injection on the bus voltage of the converter station is evaluated. The method is advantaged in that the method combines advantages of the broadband admittance matrix model and the frequency scanning method, has advantages of clear principle and easy programming, can quickly obtain the non-power frequency current injection position having great influence on the bus voltage of the converter station, and provides reference and guidance for furthersystem simulation and research.

The invention discloses a rapid calculation method of a high-voltage / extra-high voltage direct current (DC) transmission line fault voltage traveling wave. The method comprises the following steps: acquiring phase-frequency domain fault point injection current I<f> and a system node voltage equation; acquiring a plurality of sampling values of mutual impedance between a DC transmission line side and a fault point; dividing the obtained frequency response into N sections along the F (omega) frequency axis, and setting the initial ranges of orders of all frequency bands to be (N<mink>, N<maxk>); calculating the error function E<k>=F(omega<k>)-F<*(k+1)> (omega<k>) generated by a fitting function F<*(k+1)> with the order of N in the section, and taking E<k> as a fitting object of a VF method at the kth section; when k is equal to 1, stopping the calculation, and outputting a final fitting result when the F<*(1)> with the order of N is taken as the frequency to respond F (omega); obtaining a frequency domain equation of a transient voltage traveling wave U of the transmission line side; realizing frequent-time domain conversion by pull inverse transformation, and acquiring the time domain expression u(t). After the method is adopted, scientific calculation basis is provided for analysis, rapid calculation, protection evaluation and the like of DC transmission line faults of a high-voltage / extra-high voltage DC system; the method is very high in practicality during engineering practice.

The invention discloses a calculation method of a spatial circuit distribution parameter matrix based on a complex image. The method comprises the followings steps: step 1, carrying out numbering andsegmenting on each circuit; step 2, collecting numbered spatial circuit parameters, which comprise the radius of a wire, the direct current resistance of the wire, the models of poles and towers, thethree-dimensional coordinates of the poles and the towers and soil resistance rate; step 3, calculating the self-potential coefficient of each circuit and the mutual potential coefficient between circuits by adopting an average potential method according to the collected spatial circuit parameters, obtaining a potential matrix according to a calculated potential coefficient, and then carrying outpotential matrix inversion to obtain a capacitance matrix; and step 4, calculating the impedance parameter matrix of each circuit according to a complex image method, wherein the mutual impedance parameter between the circuits is calculated according to different position relationships between spatial circuits. The technical problems of relatively great errors existing in inductance and impedanceparameters during calculating the distribution parameters of the spatial circuits in the prior art and the like are solved.

The invention discloses an electromagnetic characteristic analysis method and system for an electrically large-size target with a complex structure, and the method comprises the steps: carrying out the surface triangulation of the target, setting a regional decomposition seed, completing the regional autonomous decomposition of the target based on the decomposition seed, obtaining a plurality of decomposition parts, and numbering the decomposition parts; creating a plurality of parallel threads, specifying a main thread and sub-threads, and distributing the number and serial number of decomposition parts responsible for each sub-thread; for each sub-thread, constructing a comprehensive function for all responsible decomposition parts, compressing the self / mutual impedance matrix and the excitation matrix of the decomposition parts by utilizing the comprehensive function, and reporting a result to a main thread; the main thread detects connection boundaries between different decomposition components, and calculates a self / mutual impedance matrix and an excitation matrix of the connection boundaries; and constructing a target overall compression matrix equation, solving the equation,and combining with the comprehensive function definition to obtain the electromagnetic characteristics of the target in space. The method solves the problems of low processing efficiency and the likein the prior art, and greatly improves the comprehensive processing efficiency of the SBFM.