【作者】 杨之俊；

【导师】 丁明；

【作者基本信息】 合肥工业大学 ， 电力系统及其自动化， 2009， 硕士

【摘要】 可再生能源发电具有明显的环境效益和社会效益,因此受到越来越多的关注。由于风能蕴藏量大、分布广泛、可以再生的特点,风力发电是可再生能源发电的最常见的一种形式,其中变速恒频双馈风力发电系统己经成为风力发电中的一大重点课题。风速在风力发电模拟系统中是一个重要环节,正确的风速模型不仅能够很好的反应实际风速变化情况,而且能够给风力发电系统研究提供正确的源参数。本文列举了几种常用的风速分布模型,分析了其优缺点。本文用matlab/simulink语言实现了对组合风速数学模型的仿真,仿真结果表明该模型能够理想的反应实际风速,更适宜于风力发电系统中的动态模拟。本文提出了电网故障时的双馈风力发电系统的紧急控制策略。电网故障时如双馈风力发电机仍采用常规控制策略,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。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。本文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。更多还原

【Abstract】 Renewable energy has obvious environmental benefits and social benefits, so it gets more and more attention. Because of wind energy can reserve, has a wide range of distribution, and can be regenerated, wind power generation is one of the most common form in renewable energy. VSCF doubly-fed wind power generation system of wind power has become a major focus topics.The model of wind speed is a key in the simulated system of wind generation. Accurate model of wind speed can not only reflect the factual variety of wind speed, but also provide the study of wind generation with the accurate sources. This paper enumerates several models of wind speed, analyzes their advantages and disadvantages.This paper found an combined mathematic model of wind speed by Matlab/simulink. The result of simulation shows the model can reflect factual wind speed ideally and be more suitable for wind power system dynamic simulation.A fault control strategy of DFIG is proposed in the paper.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.更多还原