Five-level topological structure used for power conversion system

Abstract

The invention relates to a five-level topological structure used for a power conversion system. The five-level topological structure comprises twelve switch tubes, four bus capacitors and two clampingcapacitors, wherein the first to the fourth switch tubes, the seventh to the eighth switch tubes and the eleventh to the twelfth switch tubes are connected to form two T-shaped units which are connected onto a direct-current bus in parallel; a clamping resistor, a first switch tube group and a second switch tube group are arranged between the two T-shaped units; the four bus capacitors are connected onto the direct-current bus in parallel after being connected in series; the first switch tube group is serially connected among the second bus capacitor and the third bus capacitor on the direct-current bus and the clamping capacitors on the upper side and the lower side, the second switch tube group is serially connected among the second switch tube, the third switch tube and the two clamping capacitors, and an output terminal is led out between the second switch tube and the third switch tube. According to the five-level topological structure, the control process is simplified, the quantity of the switch tubes in changing on-off state in the level conversion process is reduced, the five-level topological structure has preferable fault-tolerant operation capacity and reliability, thecontrol mode can be adjusted flexibly, the dead zone effect is eliminated effectively, and the five-level topological structure can be widely applied to power conversion devices such as inverters andfrequency converters.

Description

technical field [0001] The invention relates to a level topology technology, in particular to a five-level topology structure used in a power conversion system. Background technique [0002] In recent years, high-power power conversion systems have been widely used in the fields of frequency conversion and speed regulation of high-voltage and large-capacity AC motors, operation control of large wind turbines, and high-power photovoltaic inverters. In high-power applications, how to reduce loss, improve efficiency, reduce the harmonic content of the output waveform, and improve the electromagnetic compatibility of the system are all issues that system designers need to consider. [0003] The use of multi-level technology can make the output sinusoidal voltage waveform smoother, reduce the voltage change rate, and effectively reduce the harmonic content of the output voltage. At the same time, due to the use of multi-level technology, the requirements for the withstand voltag...

AI Technical Summary

Problems solved by technology

[0005] In view of the shortcomings of the five-level structure in the prior art, such as complex switching of switching states in the process of different mode conversions, large switching losses, difficulty in midpoint potential balance, and difficulty in eliminating dead zone effects, the problem to be solved by the present invention is to provide a The five-level topology used in power conversion systems can effectively reduce the overall switching loss of the system and improve the conversion efficiency of the entire system

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