Single-Loop Robust Decoupling Control Base on Perturbation Estimation for DC-Based DFIG

Abstract

This paper presents a perturbation observer based single-loop robust decoupling control scheme (RDC-PO) for DC-based DFIG with dual voltage source converters to enhance maximum power point tracking (MPPT) and improve fault-ride-through (FRT) capability. The unknown nonlinear effects caused by aerodynamic and modeling uncertainties are aggregated into a perturbation term, which is estimated by a sliding-mode perturbation observer. Then, a single-loop linear feedback controller with no intermediate link is designed to quickly compensate disturbance estimation in real time. Furthermore, the control algorithm does not necessitate a precise DFIG model. Additionally, the incorporation of nonlinear robust control compensates for the inherent limitations of linear control, thereby endowing the proposed control algorithm with the advantages of facile implementation akin to traditional linear control and global consistency characteristic of nonlinear robust control. Simulation results show that RDC-PO has superior transient and steady-state performance compared with double-loop feedback controller (DFC) and single-loop feedback control (SFC) in MPPT and FRT. Finally, Experiment verifies the practical operability of the proposed strategy. INDEX TERMS DC-based DFIG, perturbation observer, single-loop controller, MPPT, FRT