A CHB-SST topology with high frequency chain interconnection and its control method

Abstract

The invention relates to the technical field of solid-state transformers for medium and low voltage hybrid AC and DC networking, in particular to a CHB-SST topology with high-frequency chain interconnection and a control method thereof, including: a full-bridge and capacitor structure, a high-frequency link with a full-bridge structure, and a full-bridge structure With the four active bridge converter structure and the three-phase bridge arm of the high-frequency link, the high-frequency link of the full-bridge structure and the full-bridge and capacitor structure form an isolation sub-module, and the high-frequency link of the full-bridge structure interconnects all the isolation sub-modules Together, the output ends of the full-bridge structure and the four-active bridge converter structure of the high-frequency link are connected in parallel to form a low-voltage DC bus, and each of the three-phase bridge arms includes: n Isolation sub-modules and bridge arm inductors L a , L b , L c ; The present invention eliminates the SM capacitor voltage ripple.

Description

technical field [0001] The invention relates to the technical field of solid state transformers for medium and low voltage hybrid AC and DC networking, in particular to a CHB-SST topology with high frequency chain interconnection and a control method thereof. Background technique [0002] With the increase in the penetration rate of renewable energy and the gradual increase in the proportion of DC loads, DC systems are more and more widely used in power transmission and smart grids, and the technology of transformers connecting medium and low voltage hybrid AC and DC has gradually become a research hotspot. Solid-state transformer, also known as power electronic transformer, is a new type of power electronic equipment that combines power electronic technology with high-frequency electric energy conversion technology. Connecting renewable energy and energy storage systems to make up for the shortcomings of traditional transformers. [0003] In recent years, multi-level conve...

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Problems solved by technology

Another method of software suppression is to realize the power redistribution between the three phases by injecting the current component based on the fundamental frequency to suppress the voltage fluctuation of the DC side. The above scheme reduces the voltage fluctuation of the DC side through power control. The control structure is relatively Improving the carrier modulation method is simple, but it increases the difficulty of tracking the injected waveform

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