Multifunctional mixed power electronic transformer based on MMC (multimedia card) matrix converter and control method

Abstract

The invention discloses a multifunctional mixed power electronic transformer based on an MMC (multimedia card) matrix converter and a control method. The power electronic transformer comprises a powertransformer and an MMC matrix converter, a primary winding of the power electronic transformer is connected with a power grid, a secondary winding is connected with an input end of the MMC matrix converter in a star manner, an output end of the MMC matrix converter penetrates an LC filter and is connected with an isolation transformer, one end of the isolation transformer is connected with the secondary winding, and the other end of the isolation transformer is connected with a load. According to the transformer, the electric energy conversion efficiency of the power electronic transformer isimproved, compactness of the transformer is improved, the MMC matrix converter in transformer topology is based on a modular multilevel structure, so that the transformer is applied to high-voltage high-power occasions, voltage compensation can be achieved when the power grid is faulted, the electric energy quality of the power grid is improved, arm paths of a matrix converter structure are relatively independent, and flexibility of control strategies is improved.

Description

technical field [0001] The invention belongs to the technical field of power electronics, and in particular relates to a multifunctional hybrid power electronic transformer based on an MMC matrix converter and a control method. Background technique [0002] As the basic equipment of the power system, the traditional power transformer has the characteristics of simple structure and high reliability. However, with the continuous development of the power grid system, the defects of traditional power transformer equipment such as large size, easy to generate harmonic problems, and power quality cannot be guaranteed have become increasingly prominent. In recent years, due to the rapid development of power electronic technology, especially power electronic device technology, Power Electronic Transformer (PET), as a new type of power transformer, has attracted more and more attention and attention from domestic and foreign scholars. Power electronic transformers not only have the ...

AI Technical Summary

Problems solved by technology

For the existing technical solutions using AC-DC-AC converters, since they are used in medium-high voltage and high-power applications, the input side mostly adopts H-bridge cascade structure or modular multi-level converters, and the capacitor voltage balance control very complicated

At the same time, the isolation link requires multiple DC-DC converters and medium and high frequency transformers, which is not conducive to the power density of power electronic transformers

On the other hand, the existing technical solutions using AC-AC converters are limited by the withstand voltage value of the power switching devices in the converters, making them unsuitable for high-voltage and large-capacity occasions, which limits their application range

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