Power electronic transformer and control method

Abstract

The embodiment of the invention relates to the technical field of transformers, and discloses a power electronic transformer and a control method. The power electronic transformer comprises a converter, a common direct-current bus and a DC / DC converter, the alternating-current side of the converter provides a three-phase alternating-current interface, and the direct-current side of the converter provides a direct-current interface; the direct-current interface is connected with the high-voltage side of the DC / DC converter through the common direct-current bus; and the low-voltage side of the DC / DC converter provides a low-voltage direct-current interface. According to the power electronic transformer, the converter and the DC / DC converter are connected through the common direct-current bus, compared with the prior art that each sub-module in the converter is connected with one DAB structure, the number of the DAB modules is reduced, correspondingly, the size and the weight of the powerelectronic transformer are reduced, and the cost input into the DAB modules is reduced. Besides, when the three-phase power grid is connected to the three-phase alternating-current interface of the alternating-current device, the double-frequency components of the instantaneous power value are offset, low-frequency fluctuation does not exist in the direct-current bus voltage, and the direct-current output voltage quality is improved.

Description

technical field [0001] Embodiments of the present invention relate to the technical field of transformers, in particular to a power electronic transformer and a control method. Background technique [0002] With the rapid development of future power grid technologies such as smart grid and energy Internet, power electronic transformers that can realize various functions such as voltage transformation, electrical isolation, power regulation and control, and renewable energy access have been researched on related theories and technologies. growing attention. Power transformers are generally used in medium, high voltage and high power applications, and can replace traditional power frequency transformers. Compared with traditional transformers, power electronic transformers are more suitable for applications that enrich system functions and improve system performance. At present, it mainly focuses on the on-board converter system for electric locomotive traction, smart grid, e...

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Problems solved by technology

[0003] However, the inventors have found that there are at least the following problems in the prior art: the power transformer in the prior art has a large volume and weight, correspondingly high cost, poor economy, and limited application in some working conditions

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