Investigation and intelligent control of variable speed wind energy conversion system to enhance the power quality

Abstract

The stochastic nature of the wind energy, introduces various power quality issues, while generating and integrating to the grid system. The important aspects of the power quality problems in the grid integrated Wind Energy Conversion Systems (WECS) are the voltage deviation, harmonics, and the combination of flicker and voltage fluctuation. Higher penetration levels of renewable energy into the main grids, demand higher quality of the power delivery at each power conversion stage of the Renewable Energy Systems (RES). Unlike the traditional grid, the control of the power connected to the grid needs control in each stage to be available for the utility. The output of the PMSG, the output of the Machine-Side-Converter (MSC), and the output of the Grid-Side-Converter (GSC) at the Point of Common Coupling (PCC) are the important three power processing stages at which power can be utilized. The research attempt is made to apply functional variants of power electronics devices and the control algorithms in order to provide stable power at each stage of the power conversion. The proposed wind energy conversion system is analyzed with two topologies such as three stage converter (AC-DC, DC-DC and DC-AC) and two-stage converter (AC-DC and DC-AC).WECS system with PMSG is first tested with the three-stage conversion system, which has the AC to DC conversion at the PMSG output side and a DC-DC converter following it with DC to three phase AC converters with the VSC at the grid side. The AC to DC converter being the diode rectifier and DC-DC converter being the Single Ended Primary Inductor Converter (SEPIC) with orthogonally (dq) controlled three phase inverters at the grid. newline