Sub-module topology structure with direct-current fault clearing and self-voltage-sharing capabilities

Abstract

The invention relates to a sub-module topology structure with direct-current fault removal and self-voltage-sharing capabilities, and belongs to the technical field of high-voltage flexible direct-current power transmission. The sub-module topological structure comprises an MMC sub-module. An MMC sub-module topology comprises a voltage positive electrode input port, a voltage negative electrode output port and a sub-module topology structure connected with the two ports, and the MMC sub-module topology structure further comprises two half-bridge sub-modules SM1 and SM2 which are the same in structure, a bidirectional switch, a fault loop thyristor S6 and a voltage-sharing diode D7. The two half-bridge sub-modules SM1 and SM2 are connected in a cascade mode; the bidirectional switch is arranged on a negative electrode output loop of the half-bridge sub-module SM2 in series; the fault loop thyristor S6 is arranged at the voltage negative electrode output port of the MMC sub-module topology and the positive electrode port of a capacitor C2 in the half-bridge sub-module SM2 in series; and the voltage-sharing diode D7 is connected in series between the positive electrode port of the capacitor C2 in the SM2 and the positive electrode port of a capacitor C1 in the SM1.

Description

technical field [0001] The invention relates to a sub-module topology structure capable of clearing DC faults and self-equalizing voltage, and belongs to the technical field of high-voltage flexible DC transmission. Background technique [0002] With the rapid development of renewable clean energy such as wind energy and solar energy, the use of modular multilevel converter (MMC)-based power transmission technology has become an effective solution for large-scale clean energy access to the grid. The modular multi-level voltage source converter has the advantages of flexible control of active power and reactive power, DC voltage and current, no commutation failure, and small output voltage and current harmonics, and has been recognized by various scientific research institutions and engineering technology fields widespread attention. [0003] In the rapidly developing field of ultra-high voltage and large-capacity direct current transmission, the current use of flexible dire...

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Problems solved by technology

[0005] The technical problem to be solved by the present invention is to provide a sub-module topology structure with DC fault clearing and self-balancing capabilities to solve the problem of self-clearing of fault current and equalization of capacitor voltages in sub-modules in the case of DC faults

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