Converter for converting high-voltage direct current into alternating current

Abstract

The invention discloses a converter for converting high-voltage direct current into alternating current in a high voltage direct current-light (HVDC-Light) system. The converter is characterized by comprising a direct current / direct current (DC / DC) input stage and a direct current / alternating current (DC / AC) inverting stage; the DC / DC input stage consists of a resonant soft switching converter; the secondary stage of a high-frequency transformer in the converter is provided with independent N*3 windings, the output voltage of each winding is subjected to rectification and capacitive energy storage, and N*3 mutually-isolated and equivalent independent direct current power supplies are formed; and the DC / AC inverting stage comprises N*3 power units, each power unit consists of a single-phase full-bridge inverter, the direct current input end of each power unit is connected to an independent direct current power supply, the alternating current output ends of N power units are sequentially connected in series to form an alternating current output phase of the converter, and three phases are connected into a three-phase alternating current output in a star-shaped (also called as Y-shaped) mode.

Description

technical field [0001] The invention relates to a topology structure of a semiconductor converter, in particular to a high-voltage DC-to-AC converter used in a high-voltage light direct current transmission (HVDC-Light) system to convert high-voltage direct current power into sinusoidal alternating current power. flow topology. Background technique [0002] The DC-to-AC conversion converter used in the traditional HVDC transmission system is a thyristor-based current source converter. The current harmonics injected into the AC grid; while the high-voltage light-duty DC transmission technology highlights the three major characteristics of fully-controlled power electronic devices, voltage source converters, and pulse modulation technology. Compared with traditional high-voltage DC transmission technology, it has the following advantages: 1 . Active power and reactive power can be independently controlled without additional reactive power compensation; 2. It can supply power ...

AI Technical Summary

Problems solved by technology

[0009] The technical problem solved by the present invention is: to avoid the difficult problem of the design of the control circuit in the modular multi-level converter, and to solve the design of the dynamic and static voltage equalization absorbing circuit of the IGBT in the hard switching working state of the two-level converter In order to solve the problem of difficult production and high power consumption, mature technology is used to combine a variety of mature and reliable functional topologies to form a new converter topology to convert high-voltage DC power into sinusoidal AC. The function of electric energy reduces the difficulty of making the inverter and improves the reliability

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