High-frequency chain interconnected CHB-SST topology and control method

Abstract

The invention relates to the technical field of solid-state transformers of medium and low voltage hybrid AC / DC networking, in particular to a high-frequency chain interconnected CHB-SST topology and a control method thereof. The topology comprises a full-bridge and capacitor structure, a high-frequency link of the full-bridge structure, a four-active bridge converter structure of the full-bridge structure and the high-frequency link, and a three-phase bridge arm, the high-frequency link of the full-bridge structure and the full-bridge and capacitor structure form an isolation sub-module, the high-frequency link of the full-bridge structure connects all the isolation sub-modules together, and the output ends of the four active bridge converter structures of the full-bridge structure and the high-frequency link are connected in parallel to form a low-voltage direct-current bus. Each phase of bridge arm in the three phases of bridge arms comprises n isolation sub-modules and bridge arm inductors La, Lb and Lc. According to the invention, the voltage ripple of the SM capacitor is eliminated.

Description

technical field [0001] The invention relates to the technical field of solid-state transformers for medium and low voltage mixed 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 of the penetration rate of renewable energy and the gradual increase of the proportion of DC loads, DC systems have been more and more widely used in power transmission and smart grids, and the transformer technology for connecting medium and low voltage hybrid AC and DC has gradually become a research hotspot. Solid-state transformers, also known as power electronic transformers, are new power electronic devices that combine power electronics technology with high-frequency power conversion technology. It makes up for the shortcomings of traditional transformers in terms of connecting renewable energy and energy storage systems. [0003] In recent years, multilevel convert...

AI Technical Summary

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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