摘要
双馈感应发电机(doubly-fed induction generator,DFIG)在变速恒频风电系统中得到广泛应用。近年来风力发电占供电比重增长迅速,在电网出现故障导致电压跌落后,风力机组如果纷纷解列会带来系统暂态不稳定,并可能造成局部甚至是系统全面瘫痪,故人们开始关注风力机并网并相应提出了低电压过渡要求。分析了DFIG的数学模型,提出了在电网电压骤降时DFIG的控制策略,并根据滑模变结构的控制原理,设计了一种高阶滑模变结构控制器。该方案在电网电压正常时,可使系统获得良好的动态特性实现最大风能追踪,且在电网电压骤降时,可有效地减小转子电流的冲击并抑制直流母线电压的波动。仿真结果表明了此方法的有效性。
Doubly-fed induction generator(DFIG) is widely applied in variable speed constant frequency(VSCF) wind power system.In recent years the proportion of wind power has become more and more in the electricity supply.The failure of power grid will lead to voltage drop and will cause system transient instability and may lead to partial or full paralysis.So low voltage ride through(LVRT) requirements is paied attention to integration of wind power into electric net-work.The paper analyzed the DFIG mathematical model in detailed and proposed a control strategy when grid voltage dips And according to the principle of sliding mode control(SMC), designed a higher-order SMC controller.Adopting the above control strategy the system can get good dynamical characteristics and realize the maximum power point tracking. Even though voltage sag in the power grid,the proposed control can effectively reduce the impact of the rotor currents and inhibit the DC bus voltage fluctuations.The simulation results validate the effectiveness of the control strategy.
出处
《中国电机工程学报》
EI
CSCD
北大核心
2009年第S1期178-183,共6页
Proceedings of the CSEE
基金
国家自然科学基金项目(50877017)~~
关键词
双馈感应发电机
低电压过渡
滑模变结构控制
变速恒频
doubly-fed induction generator
low voltage ride through
sliding mode control
variable speed constant frequency
