MMC (Modular Multilevel Converter) bridge arm equivalent simulation method

Abstract

The invention discloses an MMC (Modular Multilevel Converter) bridge arm equivalent simulation method which is mainly used for solving the defect of a simulation technique during the shutting of an MMC. The method comprises the following steps of 1, obtaining bridge arm operating parameters of the MMC, wherein the bridge arm operating parameters comprise bridge arm current and switch signals S1-S3 of each submodule in a bridge arm; 2, constructing a bridge arm equivalent circuit according to the bridge arm operating parameters, wherein the bridge arm equivalent circuit comprises two equivalent voltage sources, two equivalent resistors, two equivalent diodes and an equivalent thyristor; 3, building an MMC simulation system according to the bridge arm equivalent circuit, and performing simulation on the system. According to the MMC bridge arm equivalent simulation method, the complicated bridge arm circuit in the MMC is effectively equivalent to a simple circuit, the node amount and the corresponding simulation operand of the system are greatly reduced, the simulation speed of the MMC is greatly promoted, and very high simulation precision is realized during the normal operation and the shutting of the MMC.

Description

technical field [0001] The invention belongs to the technical field of electric power system simulation, and in particular relates to an equivalent simulation method of an MMC bridge arm. Background technique [0002] With the vigorous development of power electronic devices dominated by insulated gate bipolar transistors (Insulated Gate Bipolar Transistor, IGBT), voltage source converters (Voltage Source Converter, VSC) are used in new energy grid-connected and high-voltage DC transmission fields. been widely applied. Among them, the MMC (Modular Multilevel Converter, Modular Multilevel Converter) based on the modular multilevel converter has become the most promising due to its small switching loss and low stress requirements on power electronic devices. VSC topology. [0003] Among the topological structures of many MMCs, the three-phase half-bridge modular multilevel converter has received extensive attention because of its strong scalability, low switching frequency, ...

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Problems solved by technology

[0005] The above-mentioned simplified algorithm greatly improves the efficiency of steady-state simulation analysis and partial transient simulation analysis, but there is still a big limitation for the simulation of the system in the sub-module locked state, that is, they cannot calculate the diode in the simulation calculation. Interpolation for precise processing

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