44results about How to "Strong nonlinearity" patented technology

The invention discloses a transformer fault classification and identification method based on a vibration analysis method. The method comprises the following steps: S1) selecting a transformer test object, and collecting transformer vibration signals under different states as sample data; S2) calculating the sample data by utilizing a Hilbert-Huang transform EEMD (ensemble empirical mode decomposition) method to obtain an intrinsic mode function; S3) extracting characteristic vector V in each intrinsic mode function component; S4) carrying out dimensionality reduction on the characteristic vector through a principal component analysis method, coordinates being projected to a two-dimensional image; S5) carrying out classification on the sample data through a K neighbor method; S6) calculating the distance between a test sample and an original sample through a distance formula; S7) carrying out mode recognition; and S8) outputting corresponding transformer fault type in mode recognition. Operation state of a transformer can be judged visually and effectively.

The invention provides a nonlinear modeling method of a broadband piezoelectric energy capture system. The method comprises the following steps of: directly measuring nonlinear restoring force in the broadband piezoelectric energy capture system by using a force measuring instrument; fitting the data of the nonlinear restoring force in the system by adopting a polynomial equation, and then obtaining an expression of the nonlinear restoring force and parameter values in the expression; according to the Hamilton's principle, the theory of piezoelectricity, the Rayleigh-Ritz principle, the Euler-Bernoulli beam theory, the electric-field constant distribution theory and the Rayleigh theorem for damping, performing deduction to obtain an expression of a nonlinear dynamic model of the broadband piezoelectric energy capture system and parameter values in the model. According to the invention, a model with nonlinear output characteristics can be accurately predicted, and can be obtained simply.

The invention discloses a glitch-type PUF circuit employing delay tree structure, and the structure comprises a time sequence control circuit, a shift register, n delay tree circuits with the same bit structure, a delay sampling circuit, an output circuit, and n input XOR gates. The delay sampling circuit comprises n delay sampling units with the same structure, and each delay sampling unit comprises a first phase inverter and a D contactor. Each Glitch generation circuit consists of multi-stage '1' hazard circuits and '0' hazard circuits. The time sequence control circuit provides clock signal for the shift register, the delay sampling circuit and the output circuit. The time sequence control circuit enables control information to be stored in the shift register, and an input signal inputted to an n-bit Glitch generation circuit sequentially passes through each delay sampling unit of the delay sampling circuit. Each delay sampling unit decides the output data of the PUF circuit. The shift register enables the output data to be outputted to the output circuit, and to serve as the output data of the glitch-type PUF circuit. The circuit is advantageous in that the circuit is remarkable in nonlinear characteristics and can effectively solve a model attack problem.

The invention discloses a radio frequency power detection circuit which comprises a radio frequency channel and a radio frequency power detection channel. The radio frequency channel comprises a radio frequency amplifier, a radio frequency power divider and a load, the input end of the radio frequency amplifier is connected to radio frequency input, the output end of the radio frequency amplifier is connected to the radio frequency power divider, one output of the radio frequency power divider is connected to the load, and the other output is connected to the radio frequency power detection channel; and the radio frequency power detection channel comprises a matching network and a self-mixer, the input end of the matching network is connected to the output end of the radio frequency power divider, the output end of the matching network is connected to the self-mixer, and the self-mixer outputs a detection level. The radio frequency power detection circuit has the advantages that the structure is simple, the power consumption is low, the problems that in a conventional method, in order to realize the high-linearity power detection, number of stages of a logarithmic amplifier needs to be increased, and the ballast needs to carry out ballasting on the output of each stage of logarithmic amplifier at the same time are solved, at the same time, the problem that more errors are introduced due to complex circuits in a traditional mode is solved, and the detection precision is improved.

The invention relates to a helical compressed metal spring (helical spring for short) used as an elastic element in mechanical industry, especially heavy duty, vehicle, mine and oscillating machinery, in particular to a pitch-varying helical metal rubber composite spring which belongs to the technical field of oscillating utilization engineering. The pitch-varying helical metal rubber composite spring is formed by compounding a pitch-varying helical metal spring and a rubber cladding layer; the pitch-varying helical metal spring is coiled by a steel wire; and the rubber cladding layer is arranged outside the pitch-varying helical metal spring to form the pitch-varying helical metal rubber composite spring. The rubber cladding layer has a columnar structure and can be made into an inner and outer helical shape or inner and outer columnar shape. The pitch-varying helical metal spring is at least provided with three circles of effective helixes, and at least two circles of effective pitches of the helixes are different pitches.

The invention discloses an AC/DC system stability domain analysis method based on a quadratic sum decomposition optimization algorithm, and the method comprises the steps: building an AC/DC hybrid power system mathematic model for transient stability analysis through considering the control state switching characteristics of a DC converter; converting a stable balance point of the mathematical model of the AC-DC hybrid power system to an original point by utilizing the stable balance point solved by load flow calculation; converting a trigonometric function in the mathematical model of the AC/DC hybrid power system into a polynomial so as to be suitable for a quadratic sum decomposition optimization algorithm; and according to the Lyapunov stability theory and the alternating-current and direct-current hybrid power system mathematical model, solving the stability domain of the alternating-current and direct-current hybrid power system in each control mode by utilizing a quadratic sum decomposition optimization algorithm. The method provided by the invention is suitable for a power system with higher dimension and stronger nonlinearity, can be used for analyzing and evaluating influence factors of transient stability, and is beneficial to transient control and parameter optimization of the power system.

The invention relates to a large-rigidity dexterous full-component friction identification servo feeding device and method. The device is capable of respectively measuring the friction force in the mechanisms, accurately identifying the friction parameters, and mounting most of the current universal models of torque sensors, force sensors, grating scales, switches and proximity switches; and the new structural design is capable of improving the overall rigidity of the device while ensuring the measurement accuracy and structural flexibility. The above sensors can be disassembled and replaced;and after removing a force sensor and a torque sensor, the device is a ball screw/linear guiderail feeding mechanism which can be used for the comparison experiment of friction compensation to verifythe effectiveness of the new method. According to the device and method, a GMS (generalized Maxwell slip) model is used to establish a refined friction model of the servo feeding system. A novel timedomain identification method is adopted, so that the friction parameters of each component of the device can be effectively identified.

The invention discloses an assembly type shear connector whole-process slip calculation method, which comprises the following steps: S1, determining assembly type composite beam section geometric parameters and a plate height analytical expression: epsilonct is nominal tensile strain calculated for concrete; epsilonP0 is the prepressing strain of the upper edge of the concrete slab; epsilont is concrete limit tensile strain; And S2, according to the balance relation of the internal force of the composite beam in the microsection. The invention has the advantages that: with the increase of load, the slippage is also increased; In different stages, the cracking slip increment increase speed is increased along with load increase, and obvious nonlinearity is shown; Precast concrete bridge roadslab joints of the tension area of the fabricated composite beam crack, so that the slippage of the composite beam is increased compared with that of a conventional composite beam, the influence is considered, the slippage calculation result is accurate, the rigidity and the bearing capacity of the composite beam are calculated without errors, the result is accurate, and the result calculation precision and the structural safety are guaranteed.

The invention relates to a 10000 volt power grid neutral point grounding device and belongs to the field of power system neutral point grounding technology. A 10000 volt power grid neutral point is connected to a first nonlinear resistor through an isolation switch; two ends of the first nonlinear resistor are connected to a fast current limiting fuse parallelly, and parallelly-connected circuits are connected to a second nonlinear resistor; two ends of the second nonlinear resistor are parallelly connected to branch circuits which are serially connected with multiple special fuses and multiple nonlinear resistors, and parallelly-connected circuits are grounded through a zero sequence current transformer; signals acquired by the zero sequence current transformer enter a signal controller and are used for controlling the isolation switch and the fast current limiting fuse to act. The device has high power supply reliability, excellent voltage protection performance and the advantages of a low-resistance grounded system and the advantages of large capacity, low cost, simple structure and small occupied area, and the application range of the device is expanded.

The invention discloses a low-temperature sintered V series ZnO voltage-sensitive ceramic material and a preparation method thereof, and belongs to the technical field of functional ceramic preparation and application. The low-temperature sintered V series ZnO voltage-sensitive ceramic material uses ZnO-V2O5 as a matrix, and oxides of Mn, Nb, Gd and Er as modified additives. The preparation method includes mixing, ball milling, drying, granulation, sieving, molding for forming, sintering and silver electrode preparation. The V1mA of ZnO pressure-sensitive ceramic material obtained by the invention has varistor voltage from 200 to 400 V / mm, nonlinear coefficient alpha greater than 20, and leakage current IL of 0.10- 0.35 mA; and the sintering temperature is 800 to 950 DEG C. compared to the Bi series and Pr series ZnO voltage-sensitive ceramic materials, the V series ZnO voltage-sensitive material provided by the invention has greatly reduced sintering temperature, good comprehensive performance, and simple preparation process, safety and reliability, and is expected to realize low temperature co-firing of MLV ceramic layer voltage-sensitive material with a silver electrode.

The invention uses an energy saving method for a new intermediate warehouse style coal grinding machine aiming at improving the automatic control level of the coal grinding machine, the optimum charge of steel balls is optimized by a fuzzy controller, so that the coal grinding machine operates in coordination with a boiler, and the coal grinding machine operates effectively and economically.

The invention discloses a double-drum and double-mass vibration mill adopting variable-pitch non-closed-coil springs and media in the mixed density. The vibration mill comprises a main vibration system and a vibration isolating system; the main vibration system comprises a motor controlled by a frequency converter and arranged on a motor support; a vibration exciter shaft is connected with an outer shaft of the motor through a coupling; the vibration exciter shaft is arranged on a machine seat; the machine seat of the vibration exciter shaft is fixedly connected between upper drum and a lower drum, and an upper mass is formed; the upper grinding drum and the lower grinding drum are arranged on the upper mass; a vibration exciter is mounted between connecting plates of the upper grinding drum and the lower grinding drum of the upper mass and becomes a vibration exciting source of the whole mill; the vibration isolating system comprises a lower mass connected with a main vibration spring group; the other end of the lower mass is connected with vibration isolating springs; and the vibration isolating springs are connected with a foundation through a base. The vibration mill has the characteristics of being capable of realizing ultrafine particle refining, realizing de-agglomeration and narrowing the powder product distributing zone, low in energy consumption, high in grinding efficiency, high in energy utilization rate, capable of realizing effective energy storage, saving energy, running stably and remarkably reducing the noise, good in vibration isolating effect and the like.

The invention provides a chemical laboratory risk early warning method based on a discrete Hopfield neural network. Actual results of a ventilation and illumination equipment operation condition a1, a temperature and humidity control equipment operation condition a2, a circuit system operation condition a3, a dangerous chemical storage environment condition a4, a dangerous chemical chemical property preservation condition a5, an experimental instrument safety inspection condition a6, an experimental instrument safety operation condition a7, a safety indication sign condition a8, a fireproof and explosion-proof equipment operation condition a9, an experimental environment sanitary condition a10, an emergency equipment condition a11 and an emergency evacuation channel condition a12 are encoded and input into the constructed discrete Hopfield neural network, and the risk early warning of the multi-index assessment system for the safety condition of the chemical laboratory in the colleges and universities is realized through the characteristic of keeping unchanged after multiple iterations. The problems that a large amount of data is needed for simulation, mobility is poor, and a construction method is complex are solved, and visual, rapid and accurate risk early warning of the laboratory safety condition is achieved.

The invention discloses a DNN-based radio frequency power amplifier temperature characteristic modeling method. The method includes the steps of selecting training data and test data of a DNN model according to measured data of temperature characteristics of a radio frequency power amplifier; determining input variables and output variables of the DNN model; importing the training data into the DNN model and training the DNN model; importing the test data into the trained DNN model, comparing an output result of the DNN model with a test result and calculating errors of the output result and the test result; comparing a test error MSE of the DNN model with an expected precision value of the DNN model, and if the MSE is less than the expected precision value, completing training; if the MSEis greater than the expected precision value, adjusting parameters for retraining till the MSE is less than the expected precision value and ending training. A correlation model of performance indexes, related to temperature, of the radio frequency power amplifier is established, and prediction of the change of the performance indexes of the radio frequency power amplifier in a given temperaturerange is achieved.

The invention discloses an additional damping type nonlinear gas spring used for tuning mass damping. The nonlinear gas spring comprises a gas spring cavity and a damping cavity; a piston and a piston rod are arranged in the gas spring cavity and the damping cavity correspondingly, and the gas spring cavity and the damping cavity are connected with a damping sliding mass block through the piston rod; and the piston in the damping cavity is provided with a hole. The gas spring can achieve the function of integrating rigidity and damping, configuration of a TMD is simplified, the later system maintenance cost is greatly reduced, the vibration reduction frequency band of the gas spring is wide, the work stroke is shorter, the advantages are remarkable, and the defect of space limitation of a traditional TMD can be overcome.

The invention discloses an electricity-heat combined system considering heat exchange delay characteristics and a scheduling method thereof. The method comprises the steps of establishing a heat exchange delay model; according to the heat exchange delay model, establishing an electricity-heat combined system optimal scheduling model considering the heat exchange delay characteristic; fitting the optimal scheduling model of the electric-heat combined system, and reducing the nonlinear degree of heat transfer constraints in the scheduling model; and according to the fitted heat transfer constraints, solving the optimal scheduling model of the electricity-heat combined system and obtaining a scheduling result. An objective function in the scheduling model takes minimum system coal consumptionas an objective, and constraint conditions of the objective function comprise heat exchange process constraints and system operation constraints; the heat exchange process constraints comprise a heattransfer process constraint and a heat exchange delay constraint. According to the invention, the heat transfer process and heat exchange delay are considered, and the analysis of the heat storage, release and transfer processes is more accurate; sensitivity analysis is carried out on different factors influencing heat exchange delay; and a reference is provided for an operator to select proper parameters in scheduling.

In order to improve the level of automatic control on a coal mill, the invention adopts a novel fuzzy control method for the intermediate storage type coal mill, particularly a fuzzy control method based on a basic composite fuzzy model library and a quantification processing control rule base, so that the coordinated operation of the coal mill and a boiler can be carried out and the operation of the coal mill can be economical and efficient.