Three-stage type alternating-current/direct-current hybrid three-port power electronic transformer

Abstract

Provided in the invention is a three-stage type alternating-current / direct-current hybrid three-port power electronic transformer comprising three filter inductors LgA, LgB, and LgC, three cascaded converters CCA, CCB, and CCC, six low-frequency blocking capacitors CLFB1, CLFB2, CLFB3, CLFB4, CLFB5 and CLFB6, three high-frequency isolation transformers THF1, THF2 and THF3, and a three-phase four-wire inverter INV. According to the three-stage type alternating-current / direct-current hybrid three-port power electronic transformer, with the cascaded converters CCA, CCB, and CCC, direct AC / AC conversion form the low-frequency alternating current to the high-frequency alternating current is realized; with the high-frequency isolation transformers THF1, THF2 and THF3, direct AC / AC conversion ofthe high-frequency alternating current of electric energy is realized; and with the three-phase four-wire inverter INV, direct conversion from the high-frequency alternating current to the low-frequency alternating current and direct current is realized.

Description

technical field [0001] The invention relates to a power electronic transformer, in particular to a three-stage multi-port power electronic transformer with both AC and DC ports. Background technique [0002] As a new type of electrical equipment in the modern smart grid and energy Internet, power electronic transformers generally achieve electrical isolation, voltage conversion, power transmission and other functions through power electronic converters and high-frequency isolation transformers. Power electronic transformers require less core material than traditional power frequency transformers due to the use of high frequency transformers ranging from hundreds of Hz to tens of kHz to achieve electrical isolation. In addition, because the power electronic transformer can also provide a DC interface, it has the ability to directly access renewable energy such as photovoltaics, and at the same time, it can compensate for the reactive power and harmonics of the AC power grid, ...

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to overcome the shortcomings of the existing power electronic transformer circuit topology from input to output through many stages of power conversion, low efficiency, large number of semiconductor switching devices, poor reliability, etc., and propose a three-stage AC-DC hybrid Three-Port Power Electronic Transformer

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