PROJECT TITLE :

Control of Three-Phase Bidirectional Current-Source Converter to Inject Balanced Three-Phase Currents Under Unbalanced Grid Voltage Condition

ABSTRACT:

A single-stage, bidirectional, current-source converter (CSC) topology to interface a dc microgrid with an ac grid is reported within the literature. In this topology, underneath a balanced grid voltage condition, the dc-link inductor current will be regulated over a wide selection-from zero to rated worth-whereas the ac-aspect current has low harmonic distortion. However, unbalanced grid voltages result in second-harmonic pulsation in the current and power on the dc aspect of the converter. In addition, the ac-facet currents will be unbalanced because of the presence of a negative-sequence element. This would result in undesired tripping of the converter if one of the phase currents exceeded its rated value. Varied control loop structures for the operation of voltage-supply converter beneath unbalanced grid voltage conditions are reported within the literature. But, use of comparable management loop structures for CSC could cause unstable operation. So, a control theme to inject balanced 3-section currents into the ac grid underneath an unbalanced grid voltage condition is proposed in this paper. The stability of the proposed management theme is studied using a tiny-signal model of the converter. Performance of the proposed management theme is studied using MATLAB/Simulink and is experimentally validated.