Optimal Power Control Strategy of Maximizing Wind Energy Tracking and Conversion for VSCF Doubly Fed Induction Generator System

Abstract

This paper focuses on the development of maximum wind power extraction strategies for variable speed constant frequency (VSCF) grid-connected wind power generation systems with a doubly fed induction generator (DFIG). A new optimal control method is proposed by controlling the generator stator active and reactive power, which is based on the condition of the system operation for not only the extracted maximum power of the wind turbine below the rated wind speed but also the higher generator efficiency. Based on the DFIG mathematical models, the optimal stator reactive power value is derived for minimal machine copper losses. According to wind turbine power characteristics and generator power flow equations, the optimal stator active power reference value is also obtained for capturing maximal output power from wind turbines. A dual-passage excitation control strategy is applied to control the active and reactive power independently. Detailed simulation results have confirmed the feasibility and performance of the optimal control strategy.