139 results about "Equivalence principle" patented technology

Analyzing interactions between vias in multilayered electronic packages that include at least two spaced-apart conducting planes, and multiple vias that connect signal traces on different layers. Voltages at active via ports are represented as magnetic ring current sources, which generate electromagnetic modes inside the plane structure. Substantial electromagnetic coupling between vias occurs. A full-wave solution of multiple scattering among cylindrical vias in planar waveguides is derived using Foldy-Lax equations. By using the equivalence principle, the coupling is decomposed into interior and exterior problems. For the interior problem, the dyadic Green's function is expressed in terms of vector cylindrical waves and waveguide modes. The Foldy-Lax equations for multiple scattering among the cylindrical vias are applied, and waveguide modes are decoupled in the Foldy-Lax equations. The scattering matrix of coupling among vias is then calculated for use in determining signal reflection, transmission, and/or coupling in the electronics package.

The invention discloses a cascade full-bridge direct-current circuit breaker low-voltage equivalent test circuit and a detection method thereof. According to the equivalent test circuit and the detection method, the action process of the cascade full-bridge high-voltage direct-current circuit breaker is simulated by utilizing a low-voltage device and a circuit through impedance equivalence according to a current transfer and cut-off process time equivalence principle, the equivalence of two current conversion times of the cascade full-bridge high-voltage direct-current circuit breaker can be realized, so that the requirement for controlling and protecting equipment time sequence can be accurately verified, the quantity of transfer submodules can be different by simplifying the equivalent condition under the condition that the voltage ratio, the current ratio and the impedance ratio satisfy the proportional relation, and the equivalence of the two current conversion times can be realized. According to the equivalent test circuit, the verification for the working principle and secondary control protection device of the cascade full-bridge high-voltage direct-current circuit breaker can be realized by utilizing relatively low cost, and the working process of the high-voltage direct-current circuit breaker can be well reflected.

The invention discloses a control method for a periodic variable-thickness strip rolling speed, and belongs to the technical field of rolling. The control method comprises horizontal rolling speed control and the vertical rolling speed control of a roller, wherein the horizontal rolling speed control is performed in a way that: a thick region of a strip is rolled at a thick region rolling speed; the rolling speed starts to decrease at a near point A of a transition region and decreases to VB at a starting point B of the transition region; at the transition region, the horizontal rolling speed at the transition region is calculated according to a transition region curvilinear equation and a second flow equivalence principle; and the rolling speed starts to increase after an end point C of the transition region and increases to a thin region rolling speed at a far point D of the transition point to start to roll a thin region; the vertical rolling speed control of the roller is performed in the way that: the vertical rolling speed of the roller is 0 when the thick region of the strip is rolled; after the thick region is rolled and a rolled piece reaches the starting point B of the transition region, the roller starts downward pressing, and the vertical rolling speed of the transition region is Vdy(x); the Vdy(x) starts to decrease after reaching a maximum point Q1 and decreases to 0 at the end point C of the transition region; and the steps are repeated periodically.

The invention discloses a multi-element acceleration factor calculation method of electronic equipment. The method includes: respectively constructing single-point stress damage models for different elements influencing life of the electronic equipment, and calculating and obtaining corresponding acceleration factors; constructing a competition failure-based failure model of the entire electronicequipment on the basis of the characteristics of the electronic equipment and the single-point stress damage models; and calculating and obtaining acceleration factors of the electronic equipment on the basis of the constructed fault model of competition failure according to a statistical equivalence principle. According to the method, for the current electronic equipment of which an equipment structure and failure modes are complicated, failure mechanisms and failure forms under various stress conditions of temperature, humidity, vibration, electrical stress, combinations thereof and the likeare analyzed, a corresponding stress failure model is constructed, and thus the acceleration factors of the electronic equipment can be obtained according to the different elements, the fault model and a corresponding system life model. The method is completely suitable for accelerated testing of the entire-machine equipment, and then enables accelerated testing of the electronic equipment to bemore accurate and reliable.

The invention discloses a small-current grounding fault line selection method based on an arc suppression coil. The small-current grounding fault line selection method includes: transferring a parallel resistor mounted on a primary side of the arc suppression coil primarily into a parallel line selection resistor mounted on a secondary side of the arc suppression coil by adding a secondary winding of the arc suppression coil; and utilizing the parallel line selection resistor mounted on the secondary side of the arc suppression coil to enable active power increment flowing through grounding circuits to increase by 1-10A when a system has grounding faults. Active component of each normal circuit is small, so that increment of the faulty circuits is obvious, and directions of active current of the grounding circuit and active power of non-grounding circuit are opposite. According to an arc suppression coil electromagnetic equivalence principle that electromagnetism of the arc suppression coil is equivalent to that of the parallel resistor utilized for line selection on the primary side of the arc suppression coil, the active current increment and direction of loop circuits are tested to perform fault line selection, so that line selection accuracy can be realized, problems and risks in the existing arc suppression coil primary side line selection resistor switching are eliminated successfully, and safety and reliability of power grids are improved.

The invention provides a large-scale MIMO beam space multicast transmission method with optimal energy efficiency, which mainly comprises the following steps: a cell base station configures a large-scale antenna array, generates a large-scale beam set by beam shaping to cover the whole cell, and carries out multicast communication with a user on the generated beam. The base station estimates the statistical channel state information of each user according to the received user uplink detection signal, and performs optimal beam space power allocation according to the statistical channel state information. Among them, the proposed energy-efficient beamspace power allocation algorithm mainly utilizes Dinkelbach transform and deterministic equivalence principle, and obtains the global optimal energy-efficient beamspace multicast power allocation matrix by iteratively solving a series of convex optimization problems. And with the movement of users, the statistical channel state information between the base station and each user changes. The base station obtains the statistical channel state information according to different application scenarios, and dynamically implements the optimal energy-efficient multicast power allocation in the beam space.

The invention provides a vehicle control system based on a space vector pulse width modulation (SVPWM) algorithm. Pulse width modulated wave generated by a specific switch mode consisting of six power switch components of a three-phase power inverter based on the SVPWM algorithm is established; basic voltage vectors are combined in a switching period according to the average value equivalence principle of the SVPWM algorithm, so that the average value of the basic voltage vectors is equal to a given voltage vector; at a specific moment, the voltage vectors rotate into a specific area and are obtained through different combination of two adjacent non-zero vector and zero vector which form the area; the action time of the two vectors is applied for many times in one sampling period, so that the action time of each voltage vector is controlled, the voltage space vector rotates nearly according to a circular track, an ideal magnetic flux circle is approached by actual magnetic flux generated by different switching stages of the inverter, the switching state of the inverter is determined by the comparison result of the actual magnetic flux and the ideal magnetic flux, and pulse width modulation (PWM) control waveform is formed. The algorithm of the scheme is simple, and the voltage vector for synthesizing reference can be obtained only by performing simple logic judgment.

The invention discloses a construction method for a rock freeze-thaw damage constitutive model under the action of constant confining pressure. Based on a popularized strain equivalence principle, taking the joint action of two damage factors (freeze-thaw cycle and load) into consideration, the invention proposes an expression of a total damage variable. If the strength of a rock element body is subject to Weibull distribution, on the basis of a D-P failure criterion and geometrical conditions at peak points of a rock stress-strain curve, an expression of a random distribution variable F, a distribution parameter m and F0 is obtained, and a rock freeze-thaw damage constitutive model under the action of constant confining pressure is created. A triaxial compression experiment is carried out on a rock under the action of freeze-thaw cycle, and the experiment verifies the rationality of the model. The method disclosed by the invention is a method combined with theoretical derivation and experimental verification. The theoretical curve of the rock damage constitutive model created by the method is identical with the experimental curve, the mechanical behaviors of a rock under various confining pressures and freeze-thaw cycle numbers can be perfectly reflected, and a theoretical guidance is provided for designs and construction of cold-region projects.

The invention relates to a stud connection-based steel-concrete composite beam calculation model analysis method. The method comprises the following steps of 1, building a stud shear connector composite beam calculation analysis model; 2, proposing that the overall shear stiffness Dsc of a stud comprises the shear stiffness Ds of the stud and the stiffness Dc of concrete in the range of a concentric circle with the diameter nds; 3, introducing a reduction coefficient beta of a working state of the overall shear stiffness of the stud to obtain equivalent lateral stiffness Deq; and 4, accordingto a lateral stiffness equivalence principle, making the stud equivalent to a short steel beam unit, and proposing that different values of the equivalent diameter deq of the short steel beam unit areused for simulating the mechanical performance of the stud in different working states. The method has the advantages that the calculation process is high in efficiency; a calculation result can quantitatively reflect interface slip of a steel-concrete composite structure and stress states of parts in stress periods of the composite structure; the practicality is high; and the method is easily understood and mastered by structure designers.

The invention provides a circuit breaker breaking capacity evaluation method based on a full current equivalence principle, which belongs to the field of power grid safety stability and control. A concept of a full current effective value is introduced to evaluate the energy released by arcs of the circuit breaker during an arc extinguishing process; when short circuit happens to the power system, the short circuit current contains a periodic component and a DC component, a short circuit point DC component decay time constant in an actual operation working condition is solved; if the constant exceeds a circuit breaker standard decay time constant, evaluation on the circuit breaker short circuit current breaking capacity is carried out through a full current effective value equivalence principle in the circuit breaker actual operation working condition and a standard operation working condition; and finally, through comparing the circuit breaker breaking capacity and the short circuit current in the actual working condition, risk points existing in operation of the power grid are found out. The short circuit current actual breaking capacity of each type of circuit breakers can be effectively evaluated, and basis is provided for short circuit current suppression measure making and circuit breaker model selection in the power grid.

The invention relates to a new rock mass damage constitutive model construction method, comprising the following steps: step S10: based on strain equivalence principle, adding a bearing capacity coefficient of a damaged material to obtain a modified rock damage constitutive model; Step S20, respectively calculating a macro damage tensor of the joint and a micro damage variable of the micro crack,and establishing a mechanical model of the macro damage and the micro damage of the joint rock according to the superposition principle; Step S30: According to the damage mechanics theory, constructinga rock mass damage constitutive model with coupling of macroscopic defects and microscopic defects. The novel rock mass damage constitutive model construction method and device provided by the invention provide a simple principle, The damage constitutive model of rock mass, which is easy to operate and low in cost, is reasonable and reliable considering the coupling of macroscopic and microscopicdefects. The mining range can be delineated accurately and reasonably by using the damage constitutive model in the design of excavation slope engineering.

The invention discloses a dynamic equivalence method of an alternating-current-direct-current serial-parallel large power system based on engineering application, and belongs to the field of electric transformation and distribution. The method of the alternating-current-direct-current serial-parallel large power system based on the engineering application comprises dividing a power grid to be analysed into two parts including an external power grid and an internal power grid, detailedly imitating a 500 kV power grid inside an area, carrying out equivalence simplification on the external power grid and an internal low voltage power grid, obtaining an external simplified power grid from the external power grid through an equivalence generator by using a dynamic equivalence method based on experience, obtaining a final internal simplified power grid by carrying out equivalence simplification on the internal low voltage power grid by using the dynamic equivalence method based on physical equivalent, respectively checking equivalence effects after the external power grid and the internal power grid are in dynamic equivalence, and checking effectiveness of the entire dynamic equivalence principle and method through comparing dynamic response curves of a simplified power grid and an actual power grid in the same fault. The method of the alternating-current-direct-current serial-parallel large power system based on the engineering application has the advantages of reducing quantity of equivalence system state and the number of differential equation, improving system analysis computational efficiency, and being capable of being widely used for analytical calculation of a serial-parallel large power grid and used in the field of dispatching management of power grids.

The invention relates to a device and method for testing the superconductivity of a three-dimensional low-temperature superconducting thin film coil, belonging to the field of a low-temperature superconductivity technology and high-accuracy measurement. Particularly, the superconductivity test is carried out on the three-dimensional low-temperature superconducting thin film coil, the superconductivity of the three-dimensional low-temperature superconducting thin film coil is tested and researched by means of a vacuum and low-temperature environment provided by a low-temperature environmental system and a vacuum environmental system provided by the invention, and further the three-dimensional superconducting thin film coil is designed in an auxiliary manner. The invention designs a low-temperature system for testing the superconductivity of the three-dimensional low-temperature superconducting thin film coil, therefore, a low-temperature environment needs to be provided for superconducting coils, as described in the background technology, in the low-temperature environment provided by the invention, liquid helium is utilized as a refrigerant, and the working temperature of a testing system is ensure to reach 4.2K, namely minus 269 DEG C. Therefore, as the tested three-dimensional low-temperature superconducting thin film coil is a core part in payloads of an STEP (satellite test of the equivalence principle) jointly developed by the NASA (National Aeronautics and Space Administration) and the ESA (European Space Agency), the device and method provided by the invention belong to applied aerospace science and technology in terms of technology application.

The invention discloses an MMC DC voltage outer loop controller and a generation method thereof. According to the generation method of the controller, the influence of the submodule capacitance voltage dynamics of a modular multilevel converter and the load dynamics on the DC voltage dynamics is considered, a DC side small signal mathematical model is established, a transfer function between the DC side voltage and the active current is derived, and a target DC voltage closed-loop control model is obtained according to the transfer function so that the target DC voltage outer loop controller is obtained from the target DC voltage closed-loop control model. The DC side equivalent capacitance is derived from the angle of the circuit so as to have higher accuracy in comparison with the conventional equivalent lumped capacitance obtained by the energy equivalence principle; meanwhile, different operation state of the converter topology is considered so that the universality is high; besides, the influence of the DC side dynamic behaviors on the controller is considered, including two situations that the DC side is the constant power resistance load and the converter station load so that the range of application is wide.

The invention provides a surface exciting method applicable to calculation of direction diagrams of waveguides in different shapes. The method comprises the following steps of: 1, setting an exciting surface of a shape corresponding to the shape of the cross section of a waveguide according to the the shape of the cross section of a waveguide; 2, dividing the exciting surface into even two-dimensional meshes, wherein an equivalent electric dipole source and a magnetic dipole source are arranged in the center of each mesh; 3, obtaining electric current of all the equivalent electric dipole sources and magnetic current of all the magnetic dipole sources on the exciting surface according to an equivalence principle, wherein an electromagnetic filed on the exciting surface is a main mode in which electromagnetic wave spreads in the waveguide; 4, carrying out mesh generation on the surface of the waveguide by virtue of triangular binning so as to obtain radiation fields generated by all the equivalent electric dipole sources, wherein the radiation fields serve as exciting fields of the surface of the waveguide; establishing an electric filed integral equation according to boundary conditions of the surface of the waveguide and obtaining the induction current of the surface of the waveguide by solving the equation according to a moment method; and 5, calculating the scattering direction diagram of the waveguide according to the induction current. Waveguides in different structures and shapes can be excited by the method provided by the invention instead of different methods separately.

The invention discloses an electrolytic capacitor-free photovoltaic inverter capable of suppressing a leakage current and a control method for the photovoltaic inverter. The photovoltaic inverter consists of a photovoltaic cell array module, five power switch transistors, two power diodes, two same direct-current energy storage inductors, two same filter inductors and one filter capacitor. According to the photovoltaic inverter and the control method, the inverter topology is free of an electrolytic capacitor, so that the service life is relatively long and the grid connection of a single-stage inverter can be realized; in the five power switch transistors, the four power switch transistors are in a power frequency mode, the one power switch transistor is in a high frequency mode, and only one power switch transistor is in the high frequency mode at any moment, so that the loss of the power switch transistor is greatly reduced and the system efficiency is relatively high; the grid-connected inverter adopts an area equivalence principle-based PWM modulation policy, so that on the premise of ensuring the quality of a grid-connected current, the values of the direct-current energy storage inductors are effectively reduced and the system volume and cost are reduced; and the topology and the control method therefor can ensure a constant common-mode voltage so as to effectively reduce the leakage current.

The invention provides a large-scale MIMO downlink beam domain power distribution method based on energy efficiency and spectral efficiency joint optimization. In the method, a base station configures a large-scale antenna array, generates a large-scale beam set covering the whole cell through beam forming so as to serve a plurality of users at the same time, and implements energy efficiency spectrum effect joint optimization power distribution according to statistical channel state information of each user. The objective of power distribution optimization is to meet the system power constraint and maximize the weighted sum of energy efficiency and spectral efficiency, and a series of quasi-concave optimization problems are iteratively solved by utilizing a deterministic equivalence principle and an MM method to obtain a locally optimal power distribution matrix. In each iteration process, the quasi-concave optimization problem is decomposed into an inner layer optimization problem for solving an optimal power distribution matrix under given transmission power to maximize the system and the rate, and an outer layer optimization problem for solving the optimal transmission power. The realization complexity is low, the energy efficiency and the spectral efficiency of large-scale MIMO downlink communication can be effectively improved, and the balance between the energy efficiency and the spectral efficiency is realized.

The invention provides a large-scale MIMO non-orthogonal unicast multicast transmission power distribution method with optimal energy efficiency. The method comprises: a base station generating a large-scale beam set covering the whole cell through beam forming, and performing non-orthogonal unicast and multicast communication with a user, namely, simultaneously sending unicast and multicast signals to the user on the same time-frequency resource; and through an uplink channel detection process, the base station acquiring statistical channel state information of each user and implementing non-orthogonal unicast multicast transmission power distribution with optimal energy efficiency. According to the algorithm, a deterministic equivalence principle, an MM method and Dinkelbach transformation are mainly utilized, and a series of convex optimization sub-problems are solved through two-layer iteration to obtain unicast and multicast beam domain power distribution matrixes respectively. When the statistical channel information between the base station and each user changes, the base station can dynamically implement non-orthogonal unicast multicast transmission power distribution withoptimal energy efficiency. The method is low in implementation complexity, and the energy efficiency of large-scale MIMO non-orthogonal unicast multicast transmission can be effectively improved.

The invention discloses a pavement petroleum asphalt high temperature and low temperature using performance rapid detection method, and belongs to the field of pavement engineering. According to the pavement petroleum asphalt high temperature and low temperature using performance rapid detection method, a dynamic shear rheometer is adopted, organic combination of time scanning and frequency scanning is realized, and asphalt high temperature performance and low temperature performance are obtained via one time of scanning experiment. The pavement petroleum asphalt high temperature and low temperature using performance rapid detection method comprises following steps: 1, dynamic shear time scanning and frequency scanning of pavement petroleum asphalt are carried out using the dynamic shear rheometer so as to obtain different asphalt frequency scanning curves in a certain temperature range; 2, a temperature-rut factor change curve is drawn for regression analysis, and asphalt high temperature evaluation is carried out; and 4, parallel displacement of different temperature scanning curves is carried out based on time-temperature equivalence principle so as to obtain displacement factors, fitting is carried out based on WLF equation derived formula, pavement petroleum asphalt glass-transition temperature is obtained via back calculation, and low temperature pavement using performance rapid determination is carried out. Compared with the prior art, the pavement petroleum asphalt high temperature and low temperature using performance rapid detection method possesses following advantages: the pavement petroleum asphalt high temperature and low temperature using performance rapid detection method is rapid, and is high in efficiency, credibility, and applicability.

The invention provides a determination method of a telescopic landing gear calibration load based on a buffer compression stroke. The determination method comprises that determining the calibration compression stroke to select an appropriate calibration stroke range within a buffer compression stroke design range; grading and fixing the compression stroke; orthogonally designing calibration conditions; selecting calibration load conditions: selecting a maximum unidirectional load and a composite load in the designed operation load conditions and the corresponding stroke as an initial source for determining the calibration load conditions; equivalently determining the calibration load: after reducing the primary designed operation load conditions in a specific proportion by utilizing an equivalence principle, the primary designed operation load is mapped to different sizes of the calibration loads of every grading stroke. The determination method of a telescopic landing gear calibration load is used to design the conditions of the telescopic landing gear calibration load based on the buffer compression stroke, and is applicable to a rocker arm type landing gear with the buffer, and has wide applicability and practicability.

The invention provides a penetration damage similarity-based metal plate frame structure equivalent design method, which comprises the following steps of: determining the weight and the speed of a warhead and the geometric dimension and the material of a target plate frame structure according to the specific conditions of the warhead and a penetration ship target; enabling the prototype grillage structure reinforcing ribs to be equivalent to the thickness of a flat plate through ultimate bending moment; for the prototype material equivalent thickness flat plate, calculating the equivalent thickness of the model material flat plate through a deformation equivalent method considering the strain rate effect; converting the model material equivalent thickness flat plate into a model material grillage structure based on an extreme bending moment equivalence principle and a ship structure statistical law; based on a finite element method, calculating penetration dynamic responses of the prototype grillage structure and the model material grillage structure, wherein the penetration dynamic responses comprise the residual speed, the crevasse diameter and the plastic zone diameter, and checking effectiveness of material equivalent design. A single-layer target material equivalent design method can be guided, the similarity of the remaining speed, the crevasse and the plastic area is guaranteed, and the manufacturing cost is reduced.