Improved Adaptive Robust Control for Low Voltage Ride-Through of Front-End Speed Regulation Wind Turbine

Abstract

This paper proposes a low voltage ride-through (LVRT) control method for the front-end speed regulation (FESR) wind turbine based on an improved adaptive robust control (IARC) to find the solution of the generator parameter variation by grid voltage dip and enhance the LVRT capability of the FESR. First, the FESR system mathematical models and the control objective of LVRT are analyzed. Then, in the improved adaptive robust controller, the Lyapunov function for three sub-systems and the energy function of the system are constructed. The excitation control law and parameter replacement law of the system are obtained by the error compensation term and additional control variable. The method makes the energy function satisfy the dissipation inequalities to guarantee the stability and ability to suppress disturbance of the system. To verify the effectiveness of the proposed control method, the proposed IARC is compared with the predictive fuzzy PID (PFPID) by time-domain simulations under different fault conditions. The results show that the proposed IARC can not only realize the rapid regulation of reactive power and effective resistance to grid voltage fluctuations but also improve robustness and transient stability of the system and enhance the LVRT performance of the FESR during the grid voltage dip.

Keywords

• Front-end speed regulation (FESR) wind turbine
• grid voltage dip
• low voltage ride-through
• adaptive robust control