On closed-loop decoupling control strategy for grid-connected double-fed generator

Abstract

This paper first introduces the basic theory of double-fed wind power generation system, and builds the mathematical model in two-phase rotary coordinate system. In order to deal with the strong coupling problems, the vector control technology is introduced, and the idea of dual-fed generator stator-flux-oriented vector control strategy is presented. Based on the two-phase simplify mathematical model and stator-flux-oriented vector control strategy, no-load grid-connected control strategy and power control strategy after grid-connected for double-fed generator are introduced: they both use dual-channel closed-loop decoupling control frame, both consider rotor current's mt component as the inner-loop. By passing key control variables, the flexible connectivity between generator and grid can be carried out and the soft switch of the control strategy also can be achieved during grid-connected. In MATLAB/SIMULINK, the simulation model is set up, and the results show that the control strategy is correct and effective.