Energy equivalence modeling method for modularization multi-level converter

Abstract

The invention relates to an energy equivalence modeling method for a modularization multi-level converter. The method comprises the steps that a modularization multi-level converter bridge arm and submodule electrical independent model is established; in the submodule equivalence process, submodule switch device conducting voltage drop and submodule capacitor voltage are classified, the calculation process is simplified, the energy conservation principle is used for updating and calculating the submodule capacitor voltage, and internal characteristics of the converter are guaranteed; a modularization multi-level converter bridge arm is subjected to integral equivalence by a controlled voltage source, and accurate output characteristics of the converter are guaranteed. According to the energy equivalence modeling method, MMC modeling can be efficiently and precisely achieved in electromagnetic transient simulation, and the calculation complexity of electromagnetic transient simulation of the method is greatly lowered; the method provides a great reference function for MMC researchers, and convenience is provided for successfully developing following simulation analysis work of a system.

Description

technical field [0001] The invention relates to an energy equivalent modeling method of a modular multilevel converter. Background technique [0002] Modular multilevel converter (MMC) has received extensive attention since it was proposed, and it has shown great advantages in high voltage direct current transmission (HVDC) engineering applications, becoming the future development direction of this field. The application of MMC solves the shortcomings of traditional DC transmission, such as commutation failure, low output voltage, and high harmonic content of output voltage and current, and can realize reliable and effective power flow control. It complies with the application requirements of flexible power transmission in the current environment of large power grid interconnection and smart grid. [0003] Since the MMC technology is still in the stage of application development, the operating data of the system under different working conditions are incomplete, and it is d...

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Problems solved by technology

[0013] The model modeling method based on Thevenin's equivalent principle is relatively complicated, and the sub-module capacitance update adopts traditional integration methods such as trapezoidal integration method and backward Euler method, and the calculation process ignores the capacitance voltage variation of each sub-module in the same simulation cycle The independence of the MMC affects the simulation accuracy of the internal characteristics of the MMC

The general equivalent model of the controlled source contains a large number of nonlinear components in large-scale MMC simulation, which makes the simulation time greatly increase with the increase of the number of levels, which is not suitable for large-scale simulation

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