Study on Single-Loop FCS-MPC for DC-Based DFIG System

Abstract

Doubly fed induction generator (DFIG) system suffers from complex control structure, slow dynamic response speed and cumbersome parameter design due to its traditional cascaded dual-loop control strategy. A single-loop finite control set model predictive control (SLMPC) is proposed in the paper for DC-based DFIG in DC grid, which simplifies its control structure and parameter design, and enhances system dynamic response. There are three improved aspects. First, the single-loop control structure is proposed to eliminate intermediate link in dual-loop cascaded structure, and enhance system dynamic response. Second, system reduced-order discretization algorithm is proposed by differential and integral discretization method to reduce finite control set model predictive control strategy (FCS-MPC) design difficulty. Third, cost function with nonlinear additional current limiting function is designed to protect system from overcurrent effectively. Finally, the feasibility of proposed strategy is verified by simulations and experiments.

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

“…The modeling and control strategy of AC-based DFIG cannot be directly applied to double-VSC DFIG systems, relevant research on double-VSC DFIG has thus been extensively conducted. The traditional linear control strategy used to realize the stator-rotor coordinated MPPT control, for ex- ample, air-gap flux orientation control [7], stator flux orientation control [8], model predictive control [9], single-loop finite control set model predictive control [10], single-loop feedback linearization control [11]. However, the conventional linear control strategy exhibits certain inherent limitations that cannot be disregarded, including reliance on system models, inadequate model accuracy, suboptimal efficiency, and unsatisfactory transient performance [12,13].…”