Five-level active midpoint clamping type H bridge converter

Abstract

The invention discloses a five-level active midpoint clamping type H bridge converter. The converter comprises three single-phase H bridge converters; each single-phase H bridge converter is composed of a first bridge arm and a second bridge arm; two ends of an input power supply (Vdc) are connected with two voltage dividing capacitors (C1, C2) in parallel, and then are connected with the first bridge arms and the second bridge arms in parallel; the two voltage dividing capacitors are connected in series; each bridge arm is a three-level active midpoint clamping topology; the structures of the a phase, b phase and c phase H bridge converters are the same; the a phase, b phase and c phase H bridge converters form three-phase four-wire alternating current output with the a, b and c three live lines through sharing a null line n; and the five-level active midpoint clamping type H bridge converter is formed. Each bridge arm device is equipped with anti-parallel diodes which form follow current channel; and a switch device unit capable of being switched on bi-directionally is formed. According to the converter provided by the invention, the maximum loss of each switch device can be independently controlled; the loss of each device on the bridge arms are averaged; the power capacity is improved; and the converter can be applied in a high power inverter.

Description

technical field [0001] The invention relates to a five-level converter, in particular to a five-level active midpoint clamping type H-bridge converter. Background technique [0002] Multilevel converters have received more and more attention in the field of high voltage and high power frequency conversion. Compared with two-level converters, multi-level converters have the advantages of lower output harmonic content and higher voltage output. [0003] Three-level neutral point clamped NPC converters have been widely used in the medium-voltage drive market with an output voltage lower than 6kV. Due to the limitation of the withstand voltage of power electronic devices, higher voltage levels and larger capacity output When required, frequency converters with five or more levels are required. The pure five-level NPC converter is rarely used due to the defect that the midpoint voltage is difficult to control. Among them, the NPC type H-bridge five-level converter, referred to...

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is to overcome the shortcomings of unbalanced device loss in the existing five-level NPC / H-bridge converter, and propose a five-level active neutral point clamped H-bridge converter

Images