Research On Power Control Of Doubly-fed Induction Generator

Wind power has become the fastest-growing energy of the world. In the past half of centuries, with the researchers'tireless efforts and the government's strong support, wind power technology is developed rapidly, the technical level, cost-effective and capacity is made a considerable progress, more and more large wind farms are built and putted into operation, which provide clean energy to the grid.Power control, a key part of doubly-fed induction generator(DFIG) control system, has always been a focus of experts and scholars'research in every country. The paper intends to study the power control strategy of DFIG.Firstly, this article summarizes the development situation of wind power generation technology.Several typical wind power system were analyzed in detail.This paper explains that it is effective and feasible to see DFIG as the research object.At the same time ,it introduced the basic principle and operation characteristics of doubly-fed wind-driven generator system and established DFIG's mathematical model. According to it, a kind of vector control strategy in stator-voltage-oriented frame is put forward. Compared to the stator-flux-oriented frame, this control mode doesn't need stator-flux measurement, and can realize active and reactive the decoupling control of output power of DFIG.The control system is simulated by MATLAB/Simulink for DFIG in stator-voltage-oriented frame. The simulation results show the effectiveness of the control method when the active power and reactive power change under normal conditions. The paper introduced the two different types of active crowbar circuit respectively and investigated their operation characteristic and structure characteristic. The operation effect is simulated based on the above power control strategy to the first kind active crowbar circuit in DFIG system.Finally, we summarize the whole system and look forward to the future.