A Multifunctional Three-Phase Grid Coupled Solar PV Energy Conversion System Using Delayed µ-Law Proportionate Control for PQ Improvement

This article deals with a multiple function three-phase single-stage solar photovoltaic energy generating (PVEG) grid coupled system using distribution static compensator (D-STATCOM) features with local linear/nonlinear loads. A delayed µ-Law proportionate normalized least mean square (DMPNLMS) control strategy is presented for DSTATCOM. The control technique gives an accurate dynamic response, less steady-state error with the dc-offset rejection. Moreover, in this article, for addressing these issues such as unwanted oscillations in the grid currents, and power quality improvement, the DMPNLMS control technique is proposed. Along with it, solar PV generating system using the voltage source converter has dual capability because at one side it is used to extract the solar power for the load, and remaining power injected into the grid, and on the other side, it is also balancing the grid currents with improved power quality. The control of grid coupled solar PVEG system is validated on a laboratory prototype at the balanced/unbalanced load conditions, and abnormal/ normal grid voltage conditions. The total harmonic distortions of grid currents/voltages are found within the IEEE-519 standard.