PROJECT TITLE :

Online Reference Limitation Method of Shunt-Connected Converters to the Grid to Avoid Exceeding Voltage and Current Limits Under Unbalanced Operation—Part I: Theory

ABSTRACT:

This paper focuses the analysis around a grid-connected converter that operates underneath unbalanced voltage and current conditions. Two different situations have been selected to validate the proposed algorithms. In the first state of affairs, the converter operates as a reactive power compensator, exchanging reactive power with the grid, and minimizing the dc bus voltage oscillations. The second situation is a lot of challenging, since it operates as a load balancer. In this application, the unbalanced current consumption of the load is compensated by the converter, exchanging positive and negative sequence currents with the grid. Another objective in this second scenario is to compensate the reactive power of the unbalanced load. It's vital to focus on that in both situations, any most limit of the converter will be exceeded due to the specific unbalanced voltage and current conditions. 3 variables are considered crucial for the converter: one) output ac current limit; two) output ac voltage limit; and 3) dc bus voltage oscillation limit. So, this paper proposes a management methodology, that limits online the reactive power reference in the first state of affairs and therefore the exchanged current references within the second scenario in order to not exceed any of the mentioned vital variables. The corresponding experimental results are shown in Half II of this paper so as to validate the limitation algorithm obtained by suggests that of the mathematical analysis allotted in Part I.