Novel two-port hybrid half-full bridge sub-module MMC topology

Abstract

The invention provides a novel two-port hybrid half-full bridge sub-module (Hybrid Half-Full Bridge Sub-module, H-HFBSM) MMC topology. The novel topology comprises two classes of two-port sub-modulesA (A-Class Sub-module, A-SM) and B (B-C class Sub-module, B-SM), wherein the B-class sub-module is obtained by turning over the A-class sub-module, and an extra group of insulated gate bipolar transistors (IGBT) and a reverse parallel diode are additionally arranged in each A-class sub-module to ensure that two poles of a capacitor cannot be connected to automatically discharge. In the field of power transmission and distribution, an MMC is formed by connecting novel hybrid half-full bridge sub-modules in series. The topological matching control mode has all functions and fault crossing capability of a conventional MMC sub-module (such as full-bridge sub-module) and also has local automatic voltage sharing capability and higher current through capability, so that the demand on capacitanceof the capacitor can be reduced on the same voltage ripper amplitude of the capacitor.

Description

technical field [0001] The invention belongs to the technical field of power transmission and distribution, and in particular relates to a novel two-port half-bridge-full bridge hybrid sub-module (Hybrid Half-Full Bridge Sub-module, H-HFBSM) MMC topology. Background technique [0002] Modular multilevel converter (MMC) is the development direction of DC transmission technology in the future. MMC uses sub-module (SM) cascading to construct converter valves, which avoids the direct series connection of a large number of devices and reduces the impact on devices. Consistency requirements, while easy to expand and redundant configuration. As the number of levels increases, the output waveform is close to sinusoidal, which can effectively avoid the defects of low-level VSC-HVDC. [0003] At present, although a large number of half-bridge sub-modules (Half-bridge Sub-module, HBSM) MMCs in use have the advantages of low cost, when facing DC faults, they can only be detected by rel...

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Problems solved by technology

However, due to the freewheeling effect of the anti-parallel diode in the sub-module and the insulated gate bipolar transistor (Insulated Gate Bipolar Transistor, IGBT), the half-bridge sub-module cannot block the short-circuit current fed into the AC direction-finding fault point, so it cannot detect DC faults. the removal of

The DC fault propagation speed of the MMC-HVDC system is extremely fast. In addition, there is no mature DC circuit breaker technology at present. If the fault cannot be cleared quickly, the safe and stable operation of the power system will be seriously affected.

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