Hybrid converter topological structure and control method thereof

Abstract

The invention discloses a hybrid converter topological structure and a control method thereof. The hybrid converter topological structure comprises at least one phase of main branch circuit and at least one phase of auxiliary branch circuit, wherein each phase of the main branch circuit comprises an upper bridge arm main branch circuit and a lower bridge arm main branch circuit, each upper bridge arm main branch circuit is provided with a first thyristor valve, and each lower bridge arm main branch circuit is provided with a second thyristor valve; each phase of the auxiliary branch circuit comprises an upper bridge arm auxiliary branch circuit and a lower bridge arm auxiliary branch circuit, each upper bridge arm auxiliary branch circuit is provided with a first auxiliary reversing valve, and each lower bridge arm auxiliary branch circuit is provided with a second auxiliary reversing valve; the auxiliary branch circuit is connected in parallel with the main branch circuit and is used for assisting the main branch circuit to perform forced commutation when the commutation of the main branch circuit fails; and a switchable valve is arranged on the main branch circuit or the auxiliary branch circuit and is used for transferring the current of the main branch circuit to the auxiliary branch circuit during forced commutation. By implementing the hybrid converter topological structure and the control method thereof, the reliable turn-off of the main branch circuit and the active commutation of each phase of bridge arm are realized, the commutation failure is avoided, and the stable and safe operation of a power grid is ensured.

Description

technical field [0001] The invention relates to the technical field of commutation in power electronics, in particular to a hybrid converter topology and a control method thereof. Background technique [0002] The traditional line commutated converter high voltage direct current (LCC-HVDC) transmission system has the advantages of long-distance large-capacity transmission and controllable active power, and is widely used in the world. As the core equipment of DC power transmission, the converter is the core functional unit to realize the conversion of AC and DC power, and its operation reliability largely determines the operation reliability of the UHV DC grid. [0003] Since traditional converters mostly use semi-controlled device thyristors as the core components to form a six-pulse bridge commutation topology, each bridge arm is composed of multi-level thyristors and their buffer components connected in series. Commutation failures are prone to occur under conditions suc...

AI Technical Summary

Problems solved by technology

[0004] In view of this, the embodiment of the present invention provides a hybrid converter topology and its con

Images