Modified Vector-Controlled DFIG Wind Energy System Using Robust Model Predictive Rotor Current Control

Abstract

As wind energy (WE) technologies become more prevalent, there are significant concerns about the electrical grid’s stability. Despite their many advantages, a WE system based on a doubly fed induction generator is vulnerable to power grid disruptions. Due to being built on traditional controllers, the generator systems with standard vector control (VC) cannot resist disturbances. This paper seeks to provide a novel VC that is resistant to outer perturbations. For this purpose, a finite state space model predictive control (FS-MPC) is utilized instead of the internal current loop of the standard VC. The objective of the proposed system is to minimize the error between the measured currents and their reference values and, also, reduces the total harmonic distortion (THD) of the current. The cost function can optimize this requirement, which reduces the computation time. The VC-FS-MPC was implemented using the MATLAB, where a 1.5-MW generator operating under different conditions was used. The necessary graphical and numerical results were extracted to show the efficiency, effectiveness, and ability of the VC-FS-MPC to improve the characteristics of the studied energy system. The results show the flexibility and distinctive performance of the VC-FS-MPC in the various tests used, as the THD of stator current was reduced in the second test compared to the first test by an estimated percentage of 61.79%. Moreover, the THD of rotor current was reduced compared to the first test by an estimated percentage of 23.56%. These ratios confirm the effectiveness of the VC-FS-MPC in improving the characteristics of the proposed system.