Modular multilevel converter and hybrid double-unit sub-module

Abstract

The invention relates to a modular multilevel converter and a hybrid double-unit sub-module. The modular multilevel converter comprises six bridge arms in three phases; n sub-modules are cascaded together so as to form each bridge arm, wherein at least one sub-module is a hybrid double-unit sub-module; the hybrid double-unit sub-module includes four power modules T1, T2, T3 and T4 and two capacitors C1 and C2; the anode of T1 is connected with the anode of T4; the cathode of T2 is connected with the cathode of T3; the cathode of T1 connected with the anode of T2; the cathode of the T4 is connected with the anode of T3 through the capacitor C2; the capacitor C1 is connected between the joint point of T1 and T4 and the joint point of T2 and T3; the joint point of T1 and T2 is one port of the hybrid double-unit sub-module; and the joint point of T2 and T4 is the other port of the hybrid double-unit sub-module. The hybrid double-unit sub-module can simultaneously replace two half-bridge sub-modules, and has negative voltage characteristics of a full-bridge sub-module. With the hybrid double-unit sub-module adopted, the utilization rate of direct voltage can be improved, and the capacity of a system can be improved.

Description

technical field [0001] The invention relates to a modular multilevel converter and a hybrid twin sub-module, belonging to the technical fields of flexible direct current transmission and distribution of power systems, power electronics and user power. Background technique [0002] Modular multilevel converters (MMCs) have been successfully used in high-power converters, mainly in the field of high voltage direct current (HVDC) transmission. Compared with traditional two- and three-level voltage source converter HVDC (Voltage Source Converter based HVDC, VSC-HVDC), modular multilevel converter HVDC (MMC-HVDC) has many advantages : The AC side and the DC side can be fully controlled, the DC bus does not need to install capacitors, the power electronic equipment has redundant operation capabilities after failure, and there is no need to install AC filters, etc. Due to the unique advantages of MMC, MMC-HVDC has become the development trend in the field of HVDC in the future. ...

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is to provide a modular multi-level converter to solve the problem that the existing MMC converter cannot have the advantages of less components, high capacity and DC fault ride-through function due to the defects of sub-modules The problem

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