Nonlinear iterative simulation method based on hierarchical model

Abstract

The invention discloses a nonlinear iterative simulation method based on a hierarchical model. The nonlinear iterative simulation method specifically comprises the following steps: S1, constructing a solution matrix according to a netlist file read in by a simulation model, simulation parameter setting and a current step length; S2, updating a Jacobian matrix and a right end item according to the step length and an element model; S3, solving the matrix equation to obtain a vector solution; S4, performing equation convergence judgment, and if convergence occurs, entering the step S5; otherwise, returning to the step S2 to update the Jacobian matrix and the right-end item for iteration; S5, selecting detailed models of the elements in an element G group; S6, updating the Jacobian matrix and the right end item; S7, carrying out iteration of a simulation equation; and S8, according to an iteration result, carrying out equation convergence judgment, and if convergence is carried out, ending iteration at the current moment. According to the method, the number of iterations in the nonlinear model solving process is effectively reduced while the simulation precision is guaranteed, the solving efficiency of a solver is remarkably improved, and meanwhile the convergence performance of the system is effectively improved.

Description

technical field [0001] The invention relates to the technical field of computer virtual simulation, in particular to a nonlinear iterative simulation method based on a hierarchical model. Background technique [0002] Simulation technology is widely used in the design and analysis of physical systems such as aviation, aerospace, ships, weapons, and rail transit. The centralized parameter model plays an important role in system principle design, problem positioning, algorithm optimization, and design space exploration. Compared with the finite element model, because of its simplicity, it is suitable for the comprehensive analysis of the system, and it is also the basis for the precise analysis of the system. According to the physical characteristics of components or equipment, nonlinear characteristics of components are often encountered when building a concentrated parameter model of components. In most cases, the nonlinear characteristics of components are ignored. For exa...

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Problems solved by technology

However, the nonlinear characteristics of some components cannot be ignored in the simulation process, such as semiconductor devices in circuit simulation, whose output current shows very strong nonlinear characteristics with the change of component pin voltage, and in the circuit simulation process, the The nonlinear process operates at high frequency, therefore, it is necessary to simulate and model its nonlinear characteristics, that is, the solver must include the ability to solve nonlinear equations

In order to solve nonlinear element equations, the commonly used algorithm is the Newton-Raphson iterative method, but when using this iterative method to solve nonlinear equations, there are higher requirements for the initial solution of the equation. When the initial solution is closer to the real When solving, the equation can converge quickly. When the initial value is set unreasonably, the convergence speed of the equation may be very slow, and even cause numerical overflow and non-convergence

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