Patents
Literature
Patsnap Copilot is an intelligent assistant for R&D personnel, combined with Patent DNA, to facilitate innovative research.
Patsnap Copilot

193 results about "Laplace transform" patented technology

In mathematics, the Laplace transform is an integral transform named after its inventor Pierre-Simon Laplace (/ləˈplɑːs/). It transforms a function of a real variable t (often time) to a function of a complex variable s (complex frequency). The transform has many applications in science and engineering.

Voltage type control method for novel photovoltaic grid-connected inverter

The invention provides a voltage type control method for a novel photovoltaic grid-connected inverter and relates to a voltage type control method for the grid-connected inverter. The method aims to solve the problems that grid-connected power of the voltage control type inverter is prone to being influenced by power grid fluctuation, and direct-current bus voltage can not be stabilized. The method comprises the following steps that 1, a closed-loop feedback control method is introduced into droop control, power rings are increased, and a translation quantity delta U0 of a droop curve U0 and a translation quantity delta f0 of rated output frequency f0 of the inverter are obtained after laplace transformation of the power rings is carried out; 2, the translation quantity delta U0 of the droop curve U0 and the translation quantity delta f0 of the rated output frequency f0 of the inverter are respectively superposed to a grid-connected droop equation of the voltage type of the novel photovoltaic grid-connected inverter, the grid-connected droop equation is simplified to obtain an equation, the power rings in the equation obtained after simplification are replaced by direct-current bus voltage rings, and the novel photovoltaic grid-connected inverter can control the direct-current bus voltage. The method is mainly applied to the grid-connected inverter.
Owner:HARBIN INST OF TECH

An extraction method of blood vessel centerline based on boundary distance field

The invention discloses a high precision rapid extraction method of the centerline of blood vessels based on a boundary distance field, which mainly solves problem that both the extraction rate of blood vessel in CAT angiogram volume data and the extraction precision of centerline are low. The method comprises the following steps of using octree for partitioning the volume data and recording all blocking partition information; using relationship between maximum value and minimum value of each blocking partition and dual threshold for extracting blood vessels and calculating the boundary distance field; using the summation of reciprocal of gradient value of blood vessel voxel in the original CTA data and laplace transformation value as the initial value of the boundary distance; establishing a maximum cost spanning tree based on the boundary distance field and extracting the trunk of the tree as initial centerline of blood vessels; using gravity method for revising the initial centerline, thus leading the points on the centerline to be at the gravity center of the cross section of blood vessel lumen, thus obtaining the final blood centerline. The extraction method has the advantages of high blood vessel extraction rate, high centerline extraction precision, and is applicable to the centerline extraction of various lumen tissues.
Owner:XIDIAN UNIV

Fracture-cavity oil and gas reservoir fractured well large karst cave well testing interpretation method

The invention discloses a fracture-cavity oil and gas reservoir fractured well large karst cave well testing interpretation method. The method comprises the following steps: S1, establishing a fractured well fracture-cavity oil reservoir well testing physical model; s2, establishing a karst cave and karst cave oil drainage area radial seepage dimensionless mathematical model; s3, establishing a fracture linear seepage dimensionless mathematical model and a coupling model of the fracture linear seepage dimensionless mathematical model and the radial seepage model; s4, enabling the mathematicalmodel to be subjected to Laplace transformation and solving; s5, drawing a typical well testing double logarithm curve; s6, fitting explanation of actual test well data; s7, researching the influenceof the radius of the karst cave; and S8, researching the influence of the main fracture length. The beneficial effects of the invention are that: a fracture-cavity oil and gas reservoir fractured welllarge karst cave well test interpretation method is established; a large-scale fracturing crack seepage channel is formed by considering shaft fracturing; the pressure crack is communicated with thelarge karst cave; a large-scale karst cave is regarded as a potential body, a double-medium karst cave oil drainage area is formed with the karst cave as the center, a mathematical model is established through radial seepage of the karst cave oil drainage area and linear flow coupling of a fracturing fracture, Laplace transformation solving is conducted on the model, a typical well testing double-logarithm curve is drawn, and parameter sensitivity analysis is conducted on the model.
Owner:SOUTHWEST PETROLEUM UNIV

Longitudinal-vibration analysis method of pile foundation in radial-heterogeneity and longitudinal-stratification soil body

The invention discloses a longitudinal-vibration analysis method of a pile foundation in a radial-heterogeneity and longitudinal-stratification soil body. For the soil body around a pile, a three-dimensional axisymmetric model is adopted, vertical wave effect is considered, and the soil body around the pile is divided into any number of layer sections along a longitudinal direction; each layer section of the soil body around the pile is divided into an internal disturbance zone and an external zone along a radial direction; the internal disturbance zone is divided into any number of circle layers along the radial direction, and each circle layer of the soil body is respectively a homogeneous, isotropic, linear and viscoelastic body; a soil body in the external zone infinitely extends alongthe radial direction; for soil body material damping, viscous damping is adopted to establish a longitudinal-vibration equation of the soil body around the pile and a pile body under a three-dimensional axisymmetric condition according to basic theory of elastic dynamics; and Laplace transform and a method of separation of variables are used to solve the vibration equation to obtain a time-domainvelocity response function of any excitation force acting on a pile top.
Owner:DALIAN MARITIME UNIVERSITY

Method for calculating productivity of staged fracturing horizontal well of non-uniform shale oil reservoir

The invention discloses a non-uniform shale oil reservoir staged fracturing horizontal well productivity calculation method. The method comprises the following steps that S1, a shale reservoir is divided into a matrix transformation area and a hydraulic fracture area, and a double-area linear flow physical model is established; S2, establishing a non-uniform permeability field based on position change; S3, establishing seepage mathematical models of the matrix transformation area and the hydraulic fracture area; S4, introducing dimensionless quantity, and simplifying the seepage mathematical model by adopting Laplace transformation; S5, solving pressure solutions of the matrix transformation area and the hydraulic fracture area; and according to the relation between the oil well constant production pressure solution and the oil well constant pressure production solution under the Laplace space, the Stehfest numerical inversion method and dimensionless definition conversion are combined, and the non-uniform shale oil reservoir staged fracturing horizontal well yield is obtained. According to the method, the heterogeneity of the oil reservoir flowing area is considered, an analyticalsolution is given, the actual situation is better met, and engineering application is easier.
Owner:SOUTHWEST PETROLEUM UNIV

Photovoltaic system MPPT fuzzy active-disturbance-rejection control method, controller and system

The invention provides a photovoltaic system MPPT fuzzy active-disturbance-rejection control method, controller and system. A model of a photovoltaic power supply system based on a Boost convertor isestablished; disturbance is added around model stable working points, and a small signal dynamic equation of the Booster convertor is obtained; Laplace transformation is conducted on the small signaldynamic equation of the Booster convertor, and thus a transfer function of duty ratio disturbance quantity and photovoltaic battery output voltage disturbance quantity can be obtained; an output voltage is referred to design a first-order differential tracking device, an expanded state observer and an error state feedback control rate; and fuzzy control is used in the active-disturbance-rejection controller, the fuzzy control and the active-disturbance-rejection controller are combined to be applied to MPPT, through a fuzzy active-disturbance-rejection control strategy, the process of adjusting the parameter settings of the active-disturbance-rejection controller is simplified, adaptivity of the controller parameters is achieved, thus the MPPT control strategy has good disturbance rejection, dynamic response, stability and robustness, and the complex process of parameter setting is avoided.
Owner:UNIV OF JINAN

Voice recognition system and voice recognition device

The invention provides a voice recognition device and a system thereof, wherein the device comprises a noise reduction suppression module, which is used for carrying out noise suppression on user voice obtained in real time or other stored voice to obtain noise-reduced voice information; the noise reduction suppression module carries out noise suppression by adopting at least one of a spectrum removal method and/or a learning homologue method and/or a noise reduction automatic encoder; a conversion module, which is used for carrying out Laplace conversion on the sound information to obtain frequency spectrum information; a feature extraction module, which is used for obtaining a Meyer spectrum reciprocal and a linear cepstrum coefficient of the sound information to obtain a feature vectordescribing the sound information; a model training module, which is used for constructing a voice recognition model by using training samples, wherein the training of the voice recognition model utilizes the frequency spectrum information obtained by the conversion module and the characteristic vector extracted by the characteristic extraction module, inputting the characteristic vector obtained by the Meyer spectrum reciprocal and the linear cepstrum coefficient into an SVM layer; a sound recognition module, which is used for recognizing the sound information by using the trained sound recognition module.
Owner:广州一玛网络科技有限公司

Servo and contour error online cooperative compensation method

ActiveCN106200553AFollow-up error suppressionImproved single-axis tracking accuracyProgramme controlComputer controlLaplace transformHigh effectiveness
The invention provides a servo and contour error online cooperative compensation method, belongs to the technical field of precise high-effectiveness smart numerical control processing, and relates to a servo error compensation method and a contour error compensation method based on high-precision contour error vector estimation in the numerical control parameter curve interpolation processing process. The method comprises steps of firstly calculating a servo error compensation value which enables a system theoretical output value to be equal to an expected output value based on laplace's transformation and inverse transformation; then, bringing forward a reference point regeneration first order approximation algorithm, which is used for precisely estimating a contour error vector; and finally according to the contour error vector estimation value and based on introduction of compensation gains, achieving contour error real-time compensation. The invention improves single shaft tracking precision and multi-shaft linkage contour precision of a numerical control feeding system at the same time, achieves effective inhibition of single shaft movement servo errors, and ensures synchronous improvement of the single shaft tracking precision and the multi-shaft linkage contour precision of a numerical control system.
Owner:DALIAN UNIV OF TECH

Method for building one-dimensional cumulates in two-storied foundation load in two stages

This is a kind of founding method for the two grade adding load double floor groundwork planar solidifying body. It's a kind of solidifying method directly used in the field of civil engineering. Its building method is as follows: build equivalent relation of grading adding load double floor groundwork planar solidification; input road embankment designed parameters, that is embankment top, fundus width, embankment height and average bearing weight; input composite groundwork parameters; input down lying floor groundwork parameters; input solidifying control parameters, that is total solidifying time, the calculating point number of solidifying time, the solidifying time value, the solidifying depth point number and the solidifying depth value; have numerical value calculation,; have Laplace transform on the double floor groundwork solidifying problem equation to do value calculation, then have Laplace counter transform to the image function of effective stress by the use of Stevest inversion formula, calculate to get the sedimentation distortion displacement and hole hydraulic pressure value of every depth point, forecast the after-building sedimentation according to the sedimentation distortion of the down lying floor; output the solidifying sedimentation calculating results of every depth point.
Owner:SOUTHEAST UNIV

Method for modeling large-scale photovoltaic grid-connected system with multiple parallel-connected grid-connected inverters through considering dead zone

The invention discloses a method for modeling a large-scale photovoltaic grid-connected system with multiple parallel-connected grid-connected inverters through considering a dead zone. The method comprises the following steps: S1, during modeling, considering the influence of the dead zone, and obtaining a relation between each voltage component of dead zone distortion voltages of the inverters and ideal fundamental wave voltages output by the inverters; S2, through Laplace transformation, adding fundamental waves of the dead zone distortion voltages and introduced low-subharmonic components into an impedance model of the grid-connected system so as to obtain an impedance model of a single-inverter grid-connected system; and S3, according to the impedance model of the single-inverter grid-connected system, obtaining a Norton equivalent circuit of the large-scale photovoltaic grid-connected system with the multiple parallel-connected grid-connected inverters and obtaining output impedance at a photovoltaic power station side. According to the invention, a reference is provided for analysis of stability of the large-scale photovoltaic grid-connected system during power grid impedance change and analysis and treatment of electric energy quality.
Owner:CHONGQING UNIV

Control method for compensating electromagnetic torque to realize quick and smooth tracking of maximum wind energy

The invention discloses a control method for compensating electromagnetic torque to realize quick and smooth tracking of the maximum wind energy of a wind turbine. By virtue of compensation of the electromagnetic torque, the rotor response speed is controlled, so that the quick and smooth tracking of the maximum wind energy of the wind turbine is realized. The design process of a torque compensating link comprises the following steps: firstly, as in a steady state, the electromagnetic torque needs to correspond to a value of a best torque curve under the current speed, initially determining the functional form Kc*(Tm-Te<*>) of the electromagnetic torque compensating link, then applying a small-signal analysis method and Laplace to transform and obtain the functional form, thereby determining the functional relationship of rotor response speed and wind speed; and then according to the relationship of the rotor response speed and the wind speed, designing the mathematical expression of a compensation factor Kc in the electromagnetic torque compensating link, so as to eliminate the influence of the wind speed Vm on the rotor response speed; and finally, on the basis of eliminating the influence of the wind speed on the rotor response speed, determining the value of a parameter in the compensation factor mathematical expression by virtue of emulation, so that the rotor response speed reaches an appropriate value.
Owner:SOUTHEAST UNIV
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Try Eureka
PatSnap group products