Power electronic transformer for medium and high voltage intelligent distribution network

Abstract

The invention discloses a power electronic transformer for medium and high voltage intelligent distribution networks, which includes a modular multilevel converter on the high voltage side, an input series output parallel isolated DC-DC converter on the middle side, and a DC-DC converter on the low voltage side. Converter; the positive pole of the output of the modular multilevel converter is connected to the middle point of the first bridge arm of the inverter bridge on the input side of the first isolated DC‑DC converter module, and the negative pole is connected to the last isolated DC‑DC The negative terminal of the input capacitor of the converter module; the connection mode of two adjacent isolated DC-DC converter modules is that the negative terminal of the input capacitor of the previous module is connected to the middle point of the previous bridge arm of the inverter bridge of the latter module. The present invention can avoid the short-circuit problem of the input capacitor of the ISOP under the condition that the output voltage of the MMC module is short-circuited; the adjustment method of interleaving control is adopted between the ISOP modules, so that the input current ripple is reduced, which is beneficial to reduce the volume of the system; the cost is low and convenient Further promotion and application.

Description

technical field [0001] The invention relates to a power electronic transformer, in particular to a power electronic transformer oriented to a medium and high voltage intelligent distribution network. Background technique [0002] The popularization and application of smart grid and related technologies has effectively promoted my country's energy conservation in the energy field, promoted the grid-connected power generation of renewable energy such as wind and solar energy, and made the future grid develop in a more intelligent, flexible and interactive direction. Whether the goals and functions of the smart grid in the future, such as high power supply quality and easy access to renewable energy generation, can be realized depends largely on the performance and intelligence level of electrical equipment in the grid. [0003] Distribution transformer is the most important and widely used type of equipment in the distribution network. Its function is generally to reduce the d...

AI Technical Summary

Problems solved by technology

However, the input terminal of the ISOP isolated DC-DC converter system in this transformer adopts the method of directly connecting each module with capacitors in series to realize the series connection of the input terminals. This method will cause all The voltage dividing capacitors are shorted together and the components will be burned

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