A Method for Obtaining Power Operating Range of Modular Multilevel Converter

Abstract

The invention discloses an acquisition method for a power running range of a modular multilevel converter. The acquisition method comprises the following steps of (1) building a steady-state mathematics analysis model of the modular multilevel converter under a rotating coordinate system according to a known basis parameter of the modular multilevel converter; (2) determining a running constraint condition needed to be considered; (3) calculating the power running range under each constraint condition according to the steady-state mathematics analysis model; and (4) getting intersection of the power running range under each constraint condition, and acquiring the power running range of the modular multilevel converter under consideration of multiple running constraint conditions. According to the method considering the running constraint condition, the power running range under the consideration of the multiple running constraint conditions is obtained by building the steady-state mathematics analysis model of the modular multilevel converter under the rotating coordinate system and getting the intersection, guidance is provided for determination and optimization of the basic parameter of the modular multilevel converter (MMC), and the acquisition method has relatively high engineering significance.

Description

technical field [0001] The invention relates to the technical field of power transmission and distribution in electric power systems, in particular to a method for obtaining a power operating range of a modular multilevel converter. Background technique [0002] Due to the advantages of flexible HVDC transmission, such as narrow transmission corridors, decoupling control of active and reactive power, no need for commutation current provided by the AC system, no commutation failure problem, and the ability to connect passive or weak AC systems, the flexible HVDC project has become a global leader. It has been widely practiced within the scope and is an effective means to solve the energy and environmental crisis. Since the Modular Multilevel Converter (MMC) was proposed in 2001, due to its advantages of low loss and modularization, it has received extensive attention from academia and industry. Most flexible DC transmission projects use MMC or the same type of technology as ...

AI Technical Summary

Problems solved by technology

However, most of the more accurate mathematical analysis models of MMC are based on the three-phase stationary coordinate system. The model variables are all AC quantities. The expression of the model has strong nonlinear time-varying characteristics, and it is impossible to easily solve the power operating range according to the operating constraints.

If the simplified MMC mathematical analysis model is used, this type of model generally only considers the external characteristics of MMC, and cannot reflect the internal characteristics of MMC such as bridge arm current and sub-module capacitor voltage, and cannot be based on constraints such as bridge arm current or sub-module capacitor voltage fluctuations. Conditional solution power operation interval

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