PROJECT TITLE :

Modeling and Control of Zero-Sequence Circulating Current in Parallel Converters with Space Vector Modulation - 2017

ABSTRACT:

The employment of parallel converters is one among the most practical solutions to resolve the problem of transmitting bulk power generated in megawatt wind turbines to the grid. In spite of many benefits of paralleling, some issues should be taken into consideration. Zero-sequence circulating current flowing between parallel converters is one of those issues. Characteristic differences and discrepancy of zero-axis duty cycles of the parallel converters are thought-about as the main origins of this current. This paper investigates another source of this phenomenon in house vector modulation controlled converters. This unnoticed source is that the notable third-harmonic voltage generated in the conventional SVM. This claim is confirmed analytically and by simulations. Accordingly, several ways for reduction of this third-harmonic voltage and mitigation of the resultant zero-sequence circulating current are proposed. The performances of those ways are verified analytically and by simulations. Finally, the experimental results are presented to verify the effectiveness of the proposed methods.