基于变速恒频双馈风力发电系统的有功、无功的解耦控制,提出了电网故障时双馈电机的紧急控制策略,在Mtalab/Simulink里建立了模型,并验证了故障控制策略的正确性。在常规情况下,双馈电机转子侧的有功采用最大功率点跟踪控制,无功采用额定功率因数控制,可以获得最大的风能利用效率和较好的功率因数;但若电网故障时仍采用此常规控制策略,电网不但获取不到最大的风能利用效率和较好的功率因数,而且电网的频率和电压波动影响较大。所以在故障期间把最大功率点追踪控制和额定功率因数控制切换到频率控制和电压控制策略,通过控制有功电流分量和无功电流分量来减小或者增加有功和无功的输出,减小电网频率和电压的波动。建立了故障控制的模型,针对系统单相接地故障和两相短路故障这两种短路故障类型进行了仿真,仿真结果验证了故障控制策略的正确性,提高了风力发电系统在故障时的稳定性。
A fault control strategy of DFIG is proposed based on the active, reactive control of the decoupling for VSCF doubly-fed wind power generation system. The model is set up in MATLAB/SIMULINK.The simulation results verify the correctness of control strategy. In conventional case, the active of DFIG rotor side uses the MPPT control and the reactive uses the rated power factor control. It can get the largest wind energy utilization efficiency and better power factor, but it can't when power grid fault occurred. And the power grid voltage and frequency will fluctuate. So the MPPT control and the rated power factor control switch to frequency control and voltage control strategy when power grid fault occured, by controlling the active current and reactive current component to reduce or increase active and reactive power output, to maintain the system frequency and voltage stability. The model of controlling under fault conditions is set up. The simulation is running in two conditions such as single-phase grounding and two-phase short-circuit.The results of simulation show the correctness of fault control strategy.The stability of wind power system is enhanced under fault conditions.