Five-electrical level inverter

Abstract

The invention provides a five-electrical level inverter and belongs to the technical field of inverters. The structure of the inverter comprises an input direct current power supply, an input dividing capacitor, a three-electrical level bridge arm, a two-electrical level bridge arm, an output filter circuit and a load. The three-electrical level bridge arm consists of four switch tubes and only two switch tubes switch at high frequency at the same moment; the two-electrical level bridge arm consists of two switch tubes and the switching frequencies and output voltages of the two switch tubes are equal; as only two switch tubes of the inverter switch at high frequency at the same moment, the switching power consumption is small and the switching efficiency is high; the maximum voltage stresses of all switching tubes of the inverter are equal to an input voltage, the voltage stress of the switching tubes is low, and compared with the conventional five-electrical level inverter, the five-electrical level inverter uses fewer switching tubes, a simpler topological structure and simpler control; and due to multiple electrical level output, the volume of the output filter is reduced greatly. The inverter is suitable to be used on medium / high-voltage and high-power application occasions. In addition, the inverter has a promising application prospect in fields such as new energy interconnected power generation.

Description

Technical field: [0001] The invention relates to a five-level inverter, belonging to the technical field of power electronic converters. Background technique: [0002] An inverter is a power conversion device that converts DC power into AC power for AC loads. [0003] Multilevel power conversion technology has been a research hotspot in the field of high-voltage and high-power applications since it was proposed by Nabae et al. in 1981. Compared with the traditional two-level converter, the output waveform of the multi-level converter has better harmonic spectrum characteristics and a smaller voltage and current change rate due to the increase in the number of output levels, so the electromagnetic compatibility is good, and The voltage stress of each switching device is small, especially suitable for high-voltage and high-power applications, such as high-voltage AC speed regulation, power system static var generator, active power filter and other occasions. The general idea...

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Problems solved by technology

[0005] Aiming at the problems of increasing the number of switch tubes and complicated control caused by the increase in the number of output levels of multilevel converters, researchers have proposed a variety of technical solutions, such as the literature "Ding Kai, Zou Yunping, Cai Zhengying, Wu Zhichao, Liu Fei, Xu Xianglian. A new type of single-phase asymmetric five-level inverter, Chinese Journal of Electrical Engineering, 2004, vol.24(11): 116-120" and literature "Zhang Yun, Sun Li, Wu Fengjiang, Sun Kui. Sinusoidal pulse width modulation control of capacitor-clamped asymmetric H-bridge five-level inverter, Proceedings of the Chinese Society for Electrical Engineering, 2009, vol.29(21): 40-45” for diode-clamped and capacitor-clamped A five-level inverter with two simplified circuit structures is studied

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