Performance Investigation of Multifunctional On-Grid Hybrid Wind–PV System With OASC and MAF-Based Control

Abstract

An observer-based adaptive speed control (OASC) and a multistage adaptive filter (MAF) based control structure are proposed for an on-grid hybrid wind–photovoltaic (PV) system to deal with the two major issues such as peak wind power extraction and mitigation of power quality problems, respectively. The OASC is an adaptive control alongside exhibiting robustness against uncertainties (structured and unstructured). The objective of peak wind power extraction is met through cascaded control, which includes an inner hysteresis current control and an outer speed control based on OASC. The proposed OASC includes a disturbance observer loop with backstepping control. Moreover, it incorporates a discontinuous projection law-based adaptive parameter estimation, thereby resulting in a sense of hybrid control implementation. The outer speed control loop provides the reference stator current to the inner loop retaining maximum power point tracking. For enhancement of system reliability, another renewable source (solar PV array) is integrated at the dc link. The connection between the hybrid system and the grid is established through an inverter incorporating the proposed MAF-based control. Herein, the effects of nonlinear balanced and unbalanced loads are addressed through the incorporation of vectorial approach for extracting fundamental positive sequence components from nonlinear load currents to realize harmonic-free fundamental reference currents for the grid. The proposed controls are simulated and compared with the conventional techniques. The control implementation and performance testing are carried out on the hybrid system built in the laboratory.