Electromagnetic transient equivalent modeling method for ISOP type cascaded power electronic transformer

Abstract

The invention designs an electromagnetic transient equivalent modeling method for an input-series and output-parallel cascaded power electronic transformer with double active bridges. The core technical scheme of the invention is as follows: 1, carrying out discretization equivalence on a switch group, a capacitor, an inductor and a primary / secondary side of a transformer to form a cascaded PET adjoint circuit; 2, listing a node admittance equation of a single H-bridge-DAB module, eliminating internal nodes by utilizing a rapid nesting simultaneous solving algorithm to obtain an equivalent circuit only containing four nodes, and meanwhile, reserving admittance information of the internal nodes; 3, performing equivalent simplification between PET modules to obtain an equivalent circuit onlycontaining four nodes of a plurality of H-bridge-DAB modules, and popularizing the equivalent circuit to three phases; 4, integrally solving by using electromagnetic transient simulation software toobtain equivalent four-terminal voltage and current of each phase; and 5, inversely solving and eliminating the voltage and current of the nodes, and updating equivalent parameters of the capacitor, the inductor and the transformer branch at the current moment.

Description

technical field [0001] The invention relates to an electromagnetic transient equivalent modeling method of an ISOP type cascaded power electronic transformer, belonging to the technical field of power transmission and distribution. Background technique [0002] Power electronic transformer (Double active bridge based cascaded power electronic transformer, PET) has become the key equipment in the future intelligent distribution network due to its advantages of high conversion efficiency, small size, light weight and high power quality. The cascaded power electronic transformer based on dual active bridges is limited by the withstand voltage level of power semiconductor devices. Its high-voltage side uses multiple cascaded H-bridge (cascaded H-bridge, CHB) converters, and the low-voltage output side is connected in parallel to The same DC positive and negative poles have the advantages of high modularity, expandability, and easy implementation of redundant design. When simula...

AI Technical Summary

Problems solved by technology

When simulating power electronic transformers, due to the existence of high-frequency transformers in DAB, it is very slow to solve the simulation speed of the system containing PET with a small step size in the electromagnetic transient simulation program. Currently, there is no solution for cascaded power electronic transformers The electromagnetic transient speed-up model of

Images