电网电压不对称跌落时双馈电机的暂态分析与控制  

Transient Analysis and Control of Doubly Fed Induction Generator under Asymmetrical Voltage Dips

作　　者：吴国祥[1] 戴洋洋 顾菊平[1] 孙继国[1] 

机构地区：[1]南通大学电子信息学院,江苏南通226019

出　　处：《电气传动》2015年第8期18-23,共6页Electric Drive

基　　金：国家自然科学基金(61273024);中国博士后科学基金(2012M511092)

摘　　要：分析了电网电压不对称跌落时双馈电机的暂态性能,推导了电网故障时双馈电机的定子磁链和转子电压表达式,研究了一种双馈风力发电系统的磁链跟踪控制策略。电网故障期间定子磁链包括正负序分量和直流暂态分量,转子绕组会产生很大的电动势导致转子过流,若没有适当的保护措施,会损坏转子绕组和转子侧变换器,导致低电压穿越失败。当电网电压不对称跌落时,通过转子侧变换器的励磁控制,使转子磁链能够追踪定子磁链的变化,有效地抑制了转子电流。和其他方法相比,磁链追踪控制算法简单有效、追踪系数可控、电磁转矩振动小,是一种较为理想的低电压穿越控制方法。仿真结果验证了此控制策略的正确性与有效性。The electromagnetic transient response of the doubly fed induction generator （DFIG） under asymmetrical voltage dips was analyzed, the equations of stator flux and rotor voltage were deduced. A control strategy of flux linkage tracking was proposed. The stator flux consists of positive, negative and transient components during grid faults, large electromotive force is induced in the rotor circuit, which causes overcurrents in the rotor windings. Without proper protection scheme, the rotor windings and the converter of rotor side will be damaged, resulting in failure of the low voltage ride through（LVRT）. To suppress the rotor overcurrents, the rotor flux linkage was controlled to track a reduced fraction of the changing stator flux linkage by excitation control of the rotor side converter under asymmetrical voltage dips. Compared with other methods, the flux tracking control algorithm is simple and effective, tracking coefficient is controllable, the electromagnetic torque of the DFIG oscillates slightly, it is a ideal method of LVRT control. The simulation results of a complete system are included, demonstrating the viability of the proposed control strategy.

关 键 词：双馈电机 不对称跌落 暂态分析 低电压穿越 磁链追踪 

分 类 号：TM614[电气工程—电力系统及自动化]