34 results about "Inverse laplace transformation" patented technology

The invention relates to a three-dimensional simulation method for fractional-order electromagnetic anomalous diffusion by rational function approximation, and aims to calculate the three-dimensional time-domain induction-polarization dual-field response of the fractional-order Cole-Cole model. It mainly includes constructing the Cole-Cole model fractional transfer function and the nth order rational approximation function based on the frequency-domain rational function approximation method, and using the sum of the absolute values ​​of the real and imaginary parts of the error function as the objective function; through the auxiliary variable method, the goal is achieved For the linearization of the function, the linear programming method is used to obtain the best approximation to the rational function; the time-domain form of the conductivity is obtained by using the partial fraction expansion method and the inverse Laplace transform; it is substituted into the Maxwell equation, and the electromagnetic field is derived based on the finite difference method The iterative equation realizes the numerical calculation of the three-dimensional electromagnetic response of the fractional Cole-Cole model. The beneficial effect of the invention is that the three-dimensional time-domain electromagnetic response of the fractional Cole-Cole model can be quickly and accurately simulated, and a theoretical basis is provided for the study of electromagnetic anomalous diffusion in polarized media.

The embodiment of the present invention discloses a virtual synchronous machine damping configuration method and device. The method includes: establishing a second-order switching cycle average model of the virtual synchronous machine, and obtaining the second-order switching cycle average model of the virtual synchronous machine according to the second-order switching cycle average model. A small-signal model, a small-signal expression of the output active power, a second small-signal model of the rocking equation and a power angle equation; the output active power change is calculated according to the small-signal expression, the first small-signal model, and the second small-signal model The fourth-order transfer function of the variable to the load-side frequency change; when the load-side frequency has a step, the response function of the output active power is obtained by performing inverse Laplace transformation on the fourth-order transfer function; the response function is calculated for the maximum value, Get the maximum expression of the output active power. The invention provides a clear and effective damping configuration method for matching the energy storage capacity of the virtual synchronous machine, which is convenient for people to configure damping for the virtual synchronous machine.

The invention discloses a tracking error estimation method for a servo drive shaft, belonging to the technical field of electromechanical integration. This method first establishes the control system model of the servo drive shaft, and derives the complete expression of the tracking error in the Laplace domain; further, according to the composition characteristics of the displacement command signal, the equivalent form of the complete expression is obtained; finally, through the Laplace Inverse Steinian transform to estimate the tracking error of a servo-driven shaft in the time domain. Using the proposed method, the fast and accurate estimation of the tracking error of the servo drive shaft is realized in the time domain, which overcomes the problems of difficult operation and low efficiency of the traditional method, and provides an accurate and convenient tool for field engineers and technicians .

The invention belongs to the technical field of optical electronic devices and particularly relates to an ultrafast laser balanced detection photoelectric pulse signal shaping method and an implementation circuit. Shaping broadening processing is performed on photocurrent through an electrical means, so that differential signals caused by waveform mismatching are reduced, and the adverse effect on the balance effect is reduced. The transfer function H used by shaping broadening processing is: (imag file= 'dest_path_image 002. TIF' wi= '169' he = '24' / ), wherein s is a complex variable, (imag file= 'dest_path_image 004. TIF' wi= '23' he = '15' / ) is an inverse Laplace transformation mark, (imag file= 'dest_path_image 006. TIF' wi= '120' he = '16' / ) is a different real parameter, and the dimension is time. Various specific implementation circuits exist. The electrical shaping mode has to additional advantages of two circuits of improving the circuit high-frequency noise suppression capacity, simplifying experiment equipment, reducing the cost and improving the data accuracy and signal to noise rate.

The invention discloses a semi-analytical calculation method for the magnetic field of eddy current non-destructive testing containing columnar defects. Using mathematical physics and electromagnetic field principles, the precise analytical expression of the magnetic vector potential in the Lagrangian domain is obtained, and the magnetic vector potential level is calculated based on MATLAB. The complex expressions in numerical form are inversely transformed by numerical Laplace, and the time-domain solution of eddy current nondestructive testing signals in conductors with columnar defects is obtained. The invention can accurately and efficiently calculate the eddy current non-destructive testing magnetic field of the conductor containing columnar defects, and provides a theoretical basis for the eddy current non-destructive testing technology in the field of defect quantitative identification.

The invention discloses a variable-pitch robust control method based on a UDE for a wind generating set. The method comprises the steps of creating a dynamic model of wind-driven generators on the basis of unmodeled dynamics and disturbance of the wind generating set; defining dynamic characteristics of regulation errors and expectation errors; rewriting the dynamic model of the wind generating set and obtaining a preliminary expression of a pitch angle controller; arranging a low pass filter for carrying out approximation on non-affine uncertain items and disturbance terms of the dynamic model of the wind-driven generators, substituting the approximation result into the preliminary expression of the pitch angle controller, carrying out Laplace transformation, carrying out inverse Laplace transformation after merging and sorting and obtaining final pitch angle control signals. In the design process, the problem that the design of a non-affine system controller is difficult is solved, the unmodeled dynamics and the environmental disturbance of a system are fully considered, the structure of an obtained controller is simple, the number of needed parameters is small, the robustness is good, the anti-jamming capability is high, a more stable wind wheel rotation speed and more stable generation power can be provided, and high-quality electric energy can be provided for a power grid.

The invention discloses a characterization method for a porous structure of a regenerated cellulose material. The characterization method comprises the following steps: firstly, soaking regenerated cellulose into liquid and oscillating; secondly, carrying out nuclear magnetic relaxation hydrogen spectrum test on the regenerated cellulose treated in the first step; thirdly, carrying out inverse laplace transformation on a nuclear magnetic relaxation attenuation curve obtained by the nuclear magnetic relaxation hydrogen spectrum test to obtain parameters for characterizing the porous structure of the regenerated cellulose. According to the characterization method disclosed by the invention, the relationship that relaxation time (logarithms and horizontal coordinates) is in direct proportion to the content of pores (longitudinal coordinates) can be obtained, therefore, the sizes of the pores can be qualitatively explained; if specific values of the sizes of the pores need to be determined, different formulas are adopted for calculating according to difference of samples. According to the characterization method disclosed by the invention, drying or freeze-drying treatment of samples is not needed, so original states of the samples can be well kept.