电网故障下交流励磁双馈风力发电机变流器建模与控制

双脉宽调制(PWM)电压型变换器作为交流励磁双馈风力发电机的励磁电源,在风力发电系统得到广泛应用.电网故障时,要求网侧变换器直流链电压波动较小和转子侧变换器能有效控制转子电流,来实现发电机的不间断运行.以双PWM变换器的数学模型为依据,在电网故障时,将网侧变换器以转子侧变换器瞬时输入电流波动为附加前馈量的双环电压控制策略,转子侧变换器考虑定子磁链暂态的定子磁链定向控制策略.仿真结果表明了所提出的联合控制方案在电网故障发生和切除时能稳定控制直流链电压和转子电流,提高了DFIG风力发电系统电网故障下的不间断运行能力.

Modeling and Control for AC-exited Double-fed Wind Power Generation converter under Grid Fault

AC excited Double-fed wind power generation with the dual PWM control voltage source converter as excitation power supply were widely used in wind power generation system.The DC-link voltage of grid side converter has little fluctuated and rotor side converter can effectively control rotor current to ride through operation under the grid fault.Based on the mathematic model of the dual PWM converter,the combination control is proposed to combine a double closed-loop voltage control strategy of the grid-side converter with rotor side instantaneous input current fluctuation as a feed control signal and stator flux oriented control strategy of rotor-side converter considering stator instantaneous flux.The simulation result shows that the combination control strategy can effectively control DC-link voltage and rotor current under the grid fault occurring or removed,and to improve ride-through ability of DFIG system under the grid fault.