周香珍,周航,曲锐,吴泰宇,张顺,朱宏超.考虑转矩失衡的双馈感应风电机组低电压穿越控制研究[J].电测与仪表,2015,52(20):. ZHOU Xiang-zhen,ZHOU Hang,QU Rui,WU Tai-yu,Zhang Shun,Zhu Hong-chao.Research of Low Voltage Ride-through for Doubly Fed Induction Generator based Wind Turbines in Consideration of Unbalance of Rotor Torques[J].Electrical Measurement & Instrumentation,2015,52(20):.
考虑转矩失衡的双馈感应风电机组低电压穿越控制研究
Research of Low Voltage Ride-through for Doubly Fed Induction Generator based Wind Turbines in Consideration of Unbalance of Rotor Torques
The Crowbar circuit is put into operation to implement low voltage ride through (LVRT) for doubly fed induction generator-based wind turbine (DFIG) during the fault. If a disturbance triggers the Crowbar circuit, it will lead to unbalance of rotor torques of wind generator. The rotor speed may exceed limitation, as a result, the over-speed protection would be triggered and wind generators tripping off from grid. In this paper, the mathematical model of DFIG under dq synchronous rotating coordinate system and the theory of decoupling control of active power and reactive power are analyzed. Based on the simulation system of PSCAD/EMTDC, the DFIG system connected with grid is established. The transient process of DFIG’s over-speed trip-off caused by torque unbalance is simulated and analyzed, which has been showed that mechanical and electric transient has had a major impact on LVRT ability. Further, the traditional LVRT scheme is improved on the basis of restarting rotor-side converter and recovering the control of power during symmetrical grid fault. The simulation results showed that the improved scheme is helpful to enhance the ability of LVRT for DFIG.
