双馈异步风力发电机双电流闭环控制改进策略研究

发布时间：2018-03-29 21:18

本文选题：双馈异步风力发电机　切入点：DFIG网侧变换器　出处：《长沙理工大学》2014年硕士论文

【摘要】：全世界能源危机的大环境下,新能源的研究与开发成为研究热点,作为新能源之一的风能是一种可再生资源,全球的蕴藏量十分丰富。风力发电是一种分布式发电,风力发电机并网会对电网构成冲击,电网的一些故障也会对风力发电机安全稳定运行构成威胁,在电网发生故障时,风力发电机如果具备优良的控制性能,将极大地增强机组的低电压穿越(LVRT)能力,防止风力发电机脱离电网,保证电网稳定运行。论文首先介绍了对称电网故障下双馈异步风力发电机(DFIG)变换器常用的控制策略,目前电网故障大多是不对称电网故障,该类故障会产生负序分量,在DFIG直流侧产生二倍纹波分量,使用对称电网故障下的控制策略来解决此类新问题,因为控制模型的建立基准点已经发生改变,所以得到的控制算法不够准确,控制会有较大的误差甚至危害机组运行。论文推导了静止abc坐标系DFIG数学模型和旋转dq坐标系DFIG动态数学模型,构建了不对称电网故障时DFIG网侧变换器数学模型,在MATLAB环境中,验证了该模型建立的正确性。阐述了在该模型下“双电流闭环控制策略”的建立过程。设计了不对称电网故障时DFIG网侧变换器性能仿真试验,验证加入双环策略后,DFIG网侧PWM变换器性能变化,仿真结果表明,双环策略虽然能够有效提高DFIG“低电压穿越”性能,但是控制效果有限,存在改进空间。论文最后提出基于模糊自适应的PID控制器(Fuzzy PID)策略,该策略利用模糊自适应技术对PID控制器参数进行在线自适应调整,提出基于神经网络自适应的双电流闭环控制(NNS-DCLC)策略,该策略利用神经网络技术对PID控制器参数进行实时自适应调整,通过不对称电网故障时DFIG网侧变换器性能仿真试验,验证加入改进策略后,DFIG网侧PWM变换器性能变化,仿真结果表明,改进策略比传统双环策略,控制性能更好,Fuzzy PID策略较NNS-DCLC策略,电流控制精度更高,动态响应时间更短,对直流侧电压波动的消除更加有效。
[Abstract]:Under the environment of the global energy crisis, the research and development of new energy becomes a hot spot. As one of the new energy, wind energy is a renewable resource, and the global potential is very rich. Wind power generation is a distributed generation. Grid connection of wind turbines will impact the power grid, and some faults of the grid will also pose a threat to the safe and stable operation of wind turbines. If the power grid failure occurs, if the wind turbine has good control performance, It will greatly enhance the low voltage traversing LVRTs of the unit, prevent the wind turbine from leaving the grid and ensure the stable operation of the grid. Firstly, the paper introduces the common control strategy of the DFIGG converter under the symmetrical power grid fault. At present, most of the power network faults are asymmetric network faults, which will produce negative sequence components, produce double ripple components in the DC side of DFIG, and solve this new problem by using the control strategy under symmetrical power network faults. Because the reference point of the control model has changed, the control algorithm is not accurate enough. In this paper, the static abc coordinate DFIG mathematical model and the rotating DQ coordinate DFIG dynamic mathematical model are derived, and the DFIG grid-side converter mathematical model for asymmetric power network fault is constructed. In the MATLAB environment, the mathematical model of DFIG grid-side converter is constructed. The correctness of the model is verified. The establishment process of "double current closed-loop control strategy" under the model is described. The performance simulation test of DFIG grid-side converter is designed for asymmetric power network faults. The simulation results show that the dual-loop strategy can effectively improve the performance of DFIG "low voltage traversing", but the control effect is limited. Finally, a fuzzy adaptive fuzzy PID-based PID controller strategy is proposed, which adapts the parameters of the PID controller on line using fuzzy adaptive technology. An adaptive dual-current closed-loop control (NNS-DCLC) strategy based on neural network is proposed. The neural network technology is used to adjust the parameters of the PID controller in real time. The simulation test of the performance of the DFIG grid-side converter under asymmetric power network fault is carried out. The simulation results show that the improved strategy is better than the traditional double loop strategy, the control performance is better than the NNS-DCLC strategy, the current control accuracy is higher and the dynamic response time is shorter. The elimination of DC side voltage fluctuation is more effective.
【学位授予单位】：长沙理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM315

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