Power electronic transformer for alternating current/direct current distribution network

Abstract

The present invention provides a power electronic transformer for an alternating current / direct current distribution network. The power electronic transformer for the alternating current / direct current distribution network comprises an input stage, an isolation stage DC-DC converter and an output stage; the input stage is an MMC structure and comprises a plurality of clamping twin sub-modules which are connected in series; the isolation stage DC-DC converter comprises DC / AC modules, high-frequency transformers and AC / DC modules, the number of the DC / AC modules, the high-frequency transformers and the AC / DC modules being the same with the number of the sub-modules of the input stage; the direct current inputs of the isolation stage are connected with the CDSM direct current output ends of the sub-modules, and the isolation stage and the sub-modules share a capacitor; the direct current output ends of the isolation stage are connected in parallel through the sub-modules; and the output stage comprises one or more DC / AC modules so as to be used for supplying power for a low-voltage alternating current load and can also be connected with one or more DC / DC modules so as to be used for supplying power for a low-voltage direct-current load. With the power electronic transformer of the invention adopted, bidirectional flow of power can be realized; electric energy quality can be improved; flexible interfaces are provided; and when a fault occurs at a direct current side, quick self-clearing of the fault can be achieved. The power electronic transformer can be applied to alternating current and direct current hybrid distribution networks containing distributed power supply such as photovoltaic power supply, and various kinds of loads.

Description

technical field [0001] The invention belongs to the technical field of power electronics, and in particular relates to a power electronic transformer applied to an AC and DC distribution network. Background technique [0002] The power transformer is the key equipment in the power system. It has the functions of voltage conversion and electrical isolation, and the manufacturing process is simple and the cost is low. However, traditional transformers also have disadvantages that cannot be ignored, such as bulky size, large no-load loss, and easy to cause harmonic pollution to the power grid. Therefore, traditional power transformers can no longer meet the needs of power grid development. With the development of power electronic technology, power electronic transformer (Power Electronic Transformer) has become the focus of many scholars' research. It converts and controls energy through power electronic devices and power electronic converter technology. It has many advantage...

AI Technical Summary

Problems solved by technology

However, traditional transformers also have disadvantages that cannot be ignored, such as bulky size, large no-load loss, and easy to cause harmonic pollution to the power grid.

Therefore, traditional power transformers can no longer meet the needs of power grid development

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