摘要
讨论了电网电压骤降下双馈感应风电(DFIG)系统的低压穿越控制策略和保护方案。采用计及电网电压变化的DFIG数学模型,建立了LVRT控制模型,通过仿真详细研究了Crowbar投切策略,仿真结果验证了Crowbar电路以及控制策略的有效性,表明Crowbar电路能有效抑制转子过电流、直流母线过电压以及电磁转矩的振荡,并可在故障时向电网注入无功电流以帮助电网电压的恢复,使DFIG实现低电压穿越。测量结果表明了这种控制方式能使DFIG在电压跌落故障下实现不间断运行,有效提高了DFIG风电机组运行的可靠性。
The LVRT control strategy and protection schemes of DFIG are discussed in condition of large external voltage dip. The DFIG mathematical model considering the changed grid voltage is adopted and the control model of LVRT is established. The switching strategy of Crowbar is researched in detail during simulation. The simulation re- sults verify that Crowbar circuit and the control strategy are effective and prove that Crowbar control strategy can limit the over current in the rotor and the over voltage of the DC bus as well as the transient oscillation of the elec- tromagnetic torque efficiently. Moreover, a reactive current is injected into the grid to assist the recovery of the grid voltage, which is in favor of achieving the LVRT of DFIG. Through the measurement results, corresponding control strategies, which are available for reference to further research on control strategy based on the standard of LVRT, are investigated.
出处
《电工电能新技术》
CSCD
北大核心
2013年第3期46-50,共5页
Advanced Technology of Electrical Engineering and Energy
