Maximal Power Point Tracking under Speed-Mode Control for Wind Energy Generation System with Doubly Fed Introduction Generator

The Doubly Fed Induction Generator (DFIG) with back-to-back four-quadrant converters between its rotor winding and the grid can realize the maximal wind energy capture in variable-speed wind energy generation system. Based on the stator flux-oriented excitation vector control strategy, this paper presents that the system dynamic characteristics under speed-mode control are superior to the dynamic characteristics under current-mode control in the process of Maximum Power Point Tracking (MPPT) and brings forward the explanation based on state space theory. And it designs the gains of two typical PI controllers in the current inner loop and the speed outer loop under speed-mode control based on Internal Model Control (IMC) theory and pole assignment method, respectively. At last, simulation results in MATLAB/SIMULINK are put forward to verify the good static and dynamic performance of the designed closed-loop control system.