PROJECT TITLE :

Ride-through strategy of quasi-Z-source wind power generation system under the asymmetrical grid voltage fault - 2017

ABSTRACT:

Asymmetrical grid voltage will introduce negative-sequence current elements on the grid facet and cause giant voltage ripple of quasi-Z-source capacitors. It will cause the torque ripple of generator. This study proposes a novel control method based on super-capacitor (SC) to enhance the aptitude of uneven fault ride through in quasi-Z-source wind power generation system (WPGS). The stream of system power, within the condition of unbalanced grid voltage, is discussed very well in this study. To limit the voltage rise and suppress the two-order voltage ripple of quasi-Z-supply capacitors, the throughput power of SC is controlled by proportional-resonant controller to trace the output power subtraction between generator and quasi-Z-supply inverter. Meanwhile, the negative-sequence part of the grid-connected current is decreased considerably. Finally, simulation and experimental results are given to verify the theoretical analysis.