36results about How to "Guaranteed numerical stability" patented technology

The invention relates to a large-step-size multi-switch electromagnetic transient state simulation method capable of setting time in real time. The method includes the following steps: calculating a first step-size point state value of electromagnetic transient state and finding that the switching motion exists in the step size; performing interpolated value calculating for a first switching motion point state value; performing interpolated value calculating for a second switching motion point state value; calculating a next step-size point state value; calculating the whole step-size point state value from the state value interpolated value of the current step-size point; and calculating the whole step-size point state value from the state value extrapolated value of the current step-size point. The method can improve calculating speed of a switching subnet, is favorable for timeliness calculating, provides time margin for improvement of switching calculation accuracy, can be applied to electromagnetic transient state simulation calculating of switching characteristic circuits of real-time calculating, super real-time calculating and off-line calculating, can be compatible with various electromagnetic transient state switching algorithms, effectively improves simulation calculating speed and accuracy, and optimizes electromagnetic transient state real-time calculating performance.

The invention discloses a numerical integration method for electric power system full dynamic simulation, combining a fixed-step trapezoidal integration method and a variable-step Gear integration method organically in the full dynamic simulation. In the method, the fixed-step trapezoidal integration method, a differential equation of a dynamic element and an algebraic equation of power network are adopted to carry out iterative solution in a mechanical and electrical transient state process of the electric power system full simulation; in the method, the variable-step Gear integration method, the differential equation of the dynamic element and the algebraic equation of the power network are adopted to carry out simultaneous solution in a medium and long-term dynamic process. The fixed-step method and the variable-step method are switched automatically according to a certain strategy in the simulation. The method integrates the advantages of the two original numerical integration methods, thereby overcoming the defect of low calculational efficiency resulting from too small step in the simulation of mechanical and electrical transient state process of the electric power system ofthe existing full dynamic simulation program while ensuring numerical calculation stability and calculation accuracy.

The invention belongs to the technical field of digital filter design, and in particular relates to an interference cancellation method based on an improved all-pass fractional delay filter. The specific steps are: adopting the minimum mean square error criterion to construct an all-pass fractional delay filter Mathematical model; adopt the particle swarm optimization method based on natural selection to solve the mathematical model of described all-pass type fractional delay filter, and then construct all-pass type fractional time-delay filter; Obtain reference signal, utilize the all-pass type that constructs The type fractional delay filter performs filtering processing on the reference signal, and performs interference cancellation processing on the filtered signal and the signal received by the radar. The present invention adopts the particle swarm algorithm of natural selection, which ensures the convergence of the solution of the filter, accelerates the convergence speed, does not require complicated numerical calculations, and ensures the numerical stability of the solution of the all-pass fractional time-delay filter. Variational fractional delay filter design is more flexible.

The invention discloses a prediction method of gas-assisted injection molding gas penetration based on a finite volume method. The method includes the following steps that (1) a three-dimensional node control body is constructed by cavity entity grids to serve as a finite volume; (2) forming process parameters are set; (3) material parameters are set; (4) the flow velocity, pressure and the temperature of plastic melt are calculated; (5) the flow leading edge of the plastic melt is updated, and the time step length is determined; (6) whether the filler content of the plastic melt reaches an appointed volume or not is judged; (7) the flow velocity, pressure and the temperature of the plastic melt and the flow velocity, pressure and the temperature of gas are calculated; (8) the flow leading edge of the plastic melt and the penetration leading edge of gas are updated, and time steps are determined; (9) whether a cavity is filled or not is judged. The method is based on the three-dimensional finite volume method, a traditional finite volume method is improved, coupled flowing of the plastic melt and gas is calculated, consideration is given to strong nonlinearity among viscosity, the velocity, pressure and the temperature, and distribution of the gas-assisted injection molding gas penetration leading edge and various physical quantity fields can be accurately predicted.

The application provides a post-processing method, device, and computer equipment for model output. The recognition system obtains the probability matrix output by the speech recognition model, performs window search in the probability matrix, and performs regular processing on the probability matrix based on thresholds to eliminate the probability matrix. Invalid paths in the matrix, and the probability calculation of the next window interval of the probability matrix is ​​based on the probability result of the previous window interval, and the corresponding probability values ​​of each window interval are calculated respectively. Finally, the command word corresponding to the window interval with the highest probability value is selected as the speech recognition result. In this application, the numerical stability of the probability matrix is ​​effectively guaranteed through threshold-based rule processing. And the method of probability multiplication calculation is used to replace the log domain calculation, thereby reducing the amount of calculation. In the process of window search, the probability calculation of the next window interval is based on the probability result of the previous window interval, thereby reducing the process of repeated calculation, further reducing the amount of calculation, and effectively speeding up the processing speed.

The invention discloses a dynamic simulation method for an active distribution network based on a multi-level optimization and chasing variational iterative method. First, the variational iteration algorithm is improved in two aspects: on the one hand, on the right side of the correction functional, the The approximate analytical solution has been obtained; on the other hand, differential equations with higher coupled frequencies are preferentially calculated. Therefore, an optimization chasing variational iterative method with faster offline convergence is proposed. Secondly, based on this method, the approximate analytical solutions corresponding to the photovoltaic system in the active distribution network and the dynamic elements in the synchronous generator system are obtained. Subsequently, a multi-stage mechanism is introduced, that is, the approximate analytical solution is applied on continuous time intervals, which breaks through the limited convergence region of the original variational iteration method, so that it can be applied to active distribution systems that require accurate solutions in larger time spans. power grid simulation. This method is faster than the traditional numerical integration method.

The invention discloses a lithium-ion battery SoC (State-of-Charge) estimation method based on improved and self-adaptive dual unscented-Kalman-filters. The method mainly comprises the following steps: 1) establishing a state filter and a parameter filter of a lithium ion power battery based on an equivalent circuit model; 2) coupling the state filter and the parameter filter of the lithium ion power battery based on the equivalent circuit model, and building dual unscented-Kalman-filters; and 3) inputting operation parameters of a to-be-detected lithium ion power battery into the dual unscented-Kalman-filters, and carrying out parameter correction and stage-of-charge (SoC) estimation on a lithium ion power battery equivalent circuit model. According to the method in the invention, the effectiveness of cholesky decomposition is guaranteed, the problem that iteration is stopped due to the fact that a covariance matrix is indefinite caused by reasons such as an initial value error, noisedisturbance, calculation module floating point error and the like is overcome, and the numerical stability of the filtering process and the robustness of the algorithm are enhanced.

Supercritical water reactor core thermal coupling iterative method, after performing m times of neutronics calculations, perform a thermal hydraulic calculation, m is the set number of neutronics calculation iterations, m is greater than 5; when performing neutronics calculations In , the adaptive relaxation factor ω is introduced and the power density distribution obtained from the second to the mth execution of neutronics calculation is adjusted by using the power density distribution iterative function. The adjusted power density distribution is used for the next execution of neutronics calculation In or thermal hydraulic calculation. The invention solves the problem that iterative calculation is difficult to converge in SCWR nuclear thermal coupling calculation, and improves the calculation efficiency and numerical stability of nuclear thermal coupling calculation.