A method of modeling a hybrid MMC state space model, a steady-state analytical model and a small signal model

Abstract

The invention discloses a method of modeling a hybrid MMC state space model, a steady-state analytical model and a small signal model, belonging to the technical field of power system transmission anddistribution. The state space model includes deducing the modulated signals and output voltage reference values of the lower and upper legs of each phase to obtain the circuit dynamic model in the static coordinate system, and obtaining the dynamic phasor model of the hybrid MMC in the rotating coordinate system through the coordinate change. The steady-state analytical model includes based on the state space model, deriving the steady-state analytical model, and analyzing the solution of the steady-state analytical model under a variety of constraints. The small signal model includes deriving the small signal model of the total capacitance voltage of the bridge arm sub-module and the circulation current of the bridge arm, integrating the small signal model of the open-loop control, and deducing the small signal model of the closed-loop control on the basis of considering the control system. The method of the invention is applicable to the joint modeling of an AC system and a DC network, as well as the engineering design and operation characteristic analysis of a hybrid MMC.

Description

technical field [0001] The invention belongs to power system transmission and distribution technology, and more specifically relates to a modeling method of hybrid MMC state space, steady state analysis and small signal model. Background technique [0002] Modular multilevel converter (MMC) has the advantages of modular structure and easy expansion, and has been widely used in the field of flexible direct current transmission. Among various MMC topologies, the hybrid MMC based on Half bridge sub-module (HBSM) and Full bridge sub-module (FBSM) has AC and DC decoupling control capabilities, and can The non-blocking ride-through DC fault has broad application prospects in the field of overhead line flexible DC transmission. [0003] At present, most researches on the hybrid MMC model focus on the proportion design of sub-modules, energy balance control of bridge arm sub-modules, and DC fault ride-through control, and few involve analytical modeling of hybrid MMC. In the ratio...

AI Technical Summary

Problems solved by technology

When operating under low DC voltage, it is also necessary to avoid the one-way bridge arm current causing the half-bridge sub-modules to fail to balance voltage normally

Therefore, the modulation and control strategies of the hybrid MMC are very different from those of the half-bridge MMC, and the analytical model of the half-bridge MMC cannot be directly applied to the hybrid MMC. It is necessary to study the analytical model and operating characteristics of the hybrid MMC.

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