Enhancing the performance of grid-connected DFIG systems using prescribed convergence law.

In this paper, a robust and effective control strategy, termed high-order prescribed convergence law control (HO-PCL), is introduced for wind energy conversion systems. This innovative strategy is applied to the rotor-side converter of a doubly-fed induction generator-based wind power system and is specifically designed to address the limitations of conventional control methods, such as super-twisting algorithm (STA), integral backstepping control (IBCS), and first-order sliding mode control (1-SMC), which are prone to the chattering phenomenon. The HO-PCL strategy facilitates the independent regulation of active and reactive power, with the primary objective of enhancing the system's dynamic response by improving response time and minimizing power error. The effectiveness of the proposed control approach is evaluated through simulations conducted in the MATLAB/Simulink environment and validated via hardware-in-the-loop (HIL) testing under different operating conditions, where the performance and effectiveness are compared with that of the conventional proportional-integral (PI) controller, 1-SMC, and IBCS approaches. Simulation results show that the proposed HO-PCL approach reduces the stator current total harmonic distortion by 94.01, 91.05, and 85% compared to the PI, 1-SMC, and IBCS approaches, respectively. Additionally, it reduces response time by 99.25, 98.96, 93% relative to the same respective methods. Furthermore, the HO-PCL approach significantly improves the ripple and overshoot of power compared to other strategies. The results demonstrate its potential to advance control methodologies in wind power systems by overcoming the drawbacks of conventional techniques.