One-way full-bridge modular multilevel converter based on IGCT and control method

Abstract

The invention provides a one-way full-bridge modular multilevel converter based on IGCT and a control method. The multilevel converter comprises a plurality of bridge arms, each bridge arm comprises a plurality of same sub-modules; each sub-module comprises an IGCT one-way full-bridge module (1), a drive power source (2), a buffer circuit (3), a voltage clipping circuit (4), a DC capacitor (5), a balanced discharge circuit (6), a current acquisition circuit (8), and a submodule controller (9). The one-way full-bridge modular multilevel converter based on the IGCT realizes the functions of direct-current fault self-clearing, direct-current variable-voltage operation, power reversal and the like, has the advantages of low loss, economical efficiency and low cost, overcomes the defects of other structures, and can be widely applied to a flexible direct-current power transmission system or a hybrid direct-current power transmission system.

Description

technical field [0001] The invention belongs to the technical field of power electronics, and in particular relates to a unidirectional full-bridge modular multilevel converter based on an integrated gate commutated thyristor (IGCT) and a control method thereof. Background technique [0002] Flexible DC transmission has become the most potential new power transmission method at present, and has been applied in large-capacity transmission systems. [0003] Modular multilevel converter is the most mainstream topology used in flexible DC transmission at present. Most of the flexible direct current transmission projects that have been put into operation use conventional half-bridge modular multilevel converters based on insulated gate bipolar transistors (IGBTs), but such half-bridge modular multilevel converters are used in There are great difficulties in realizing DC fault clearance, DC variable voltage operation mode, and power inversion. At the same time, there are also dis...

AI Technical Summary

Problems solved by technology

However, the half-bridge modular multilevel converter based on IGCT does not have the function of self-clearing DC faults in the event of a DC short-circuit fault on the overhead line of the DC system, so the ability to resist DC short-circuit faults is poor

In addition, for the hybrid DC transmission system composed of grid-commutated converters and modular multi-level converters, when online power inversion is required, half-bridge modular multi-level converters based on IGCT cannot realize Continuous conversion and regulation of forward and reverse DC voltage

[0005] In the prior art, in order to achieve the purpose of fault ride-through and polarity reversal of the DC transmission system, it is necessary to use a full-bridge modular multilevel converter, and the structure of its sub-modules is as follows: figure 1 As shown, the number of power devices required by the sub-module is large, and the operating loss is also large

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