PROJECT TITLE :

Three-Phase Four-Wire Inverters Based on Cascaded Three-Phase Converters with Four and Three Legs - 2017

ABSTRACT:

In this paper, a generalization for three-phase four-wire inverters is proposed. In this generalization, an arbitrary variety of three-part four-wire dc-ac converters are cascaded by means of injection transformers, in order to compose a resultant inverter with one dc link. Its converters might have four or 3 legs composed by a pair of the complementary insulated-gate bipolar transistor. The injection transformers have completely different turns ratios calculated in order to maximise the number of levels created within the output voltage. During this manner, the converter cells inside the inverter are asymmetrical in terms of power rating. In this paper, the proposed generalization is applied to a specific case, where 2 four-wire converters are cascaded, which generates four totally different proposed configurations. These configurations are analyzed well and compared with the conventional four-leg inverter by means that of information acquired from simulation and experimental results. In these results, the proposed and conventional inverters feed an unbalanced three-phase load accordingly to the identical reference voltage, and the load current total harmonic distortion, voltage weighted total harmonic distortion, transformers and semiconductors losses, switching frequency, and power rating are analyzed so as to conclude that proposed configurations gift better performance, although they have additional semiconductors and demand injection transformers.