采用超级电容的直驱风电机组故障穿越和功率平滑控制

发布时间：2018-08-30 10:59

【摘要】：风能是绿色能源,具有分布广、可再生、无污染的特点。在风力发电领域中,直驱永磁同步风力发电机组(D-PMSG WTGS)由于其运行可靠性和控制灵活性,得到了越来越多的关注,市场份额逐渐增加。本文针对采用超级电容器储能的D-PMSG WTGS,对其故障穿越和功率平滑控制展开研究,以期进一步提高其运行性能。首先,明确了研究的目的和意义,分析了世界能源消费结构,分别阐述了现阶段风力发电和超级电容器的发展现状,综述了D-PMSG WTGS的故障穿越和功率平滑控制的研究现状。其次,给出了采用超级电容器的D-PMSG WTGS的拓扑结构,根据其结构和工作原理,推导了网侧变换器和双向Buck-Boost变换器的数学模型,包括了网侧变换器和双向Buck-Boost变换器的开关函数模型以及双向Buck-Boost变换器的状态方程模型和传递函数模型。第三,针对电网故障和电网正常两种状况,提出D-PMSG WTGS中网侧变换器和用于超级电容器存储和释放电能的双向Buck-Boost变换器的协调控制策略。采用二阶广义积分器锁相环(SOGI-PLL)检测电网电压,电网正常时,网侧变换器采用基于电压前馈的直流电压外环、电流内环的电网电压定向控制,双向Buck-Boost变换器采用电流单闭环释能控制;电网故障时,网侧变换器采用结合负序电压前馈的功率外环、电流内环控制,双向Buck-Boost变换器采用直流电压外环、电流内环双闭环控制。在Matlab/Simulink环境中进行了仿真研究,仿真结果表明,所论协调控制策略可以提高D-PMSG WTGS的故障穿越能力。第四,对D-PMSG WTGS的功率平滑控制进行研究。设计了“风速功率模型”,用来模拟风力发电机的出力随风速发生波动的状态;为实现并网功率相对平滑,网侧变换器采用电网电压定向控制,双向Buck-Boost变换器采用电流单闭环控制。其中,有功功率给定值由机侧输出功率及其平均值确定,并对比分析了数值平均法和低通滤波法获得的功率平均值的效果。仿真结果表明,采用超级电容器可以补偿D-PMSG WTGS的有功功率波动,使并网有功功率相对平滑、稳定。最后,对全文进行了总结,并就进一步研究方向进行了展望。
[Abstract]:Wind energy is a green energy, with the characteristics of wide distribution, renewable, no pollution. In the field of wind power generation, direct-drive permanent magnet synchronous wind turbine (D-PMSG WTGS) has been paid more and more attention because of its reliability and control flexibility, and its market share has gradually increased. In this paper, the fault traversing and power smoothing control of D-PMSG WTGS, with supercapacitor energy storage is studied in order to improve its performance. Firstly, the purpose and significance of the research are clarified, the world energy consumption structure is analyzed, the current development of wind power generation and supercapacitor is described, and the research status of D-PMSG WTGS fault traversing and power smoothing control is summarized. Secondly, the topology of D-PMSG WTGS with supercapacitor is given. According to its structure and working principle, the mathematical models of grid-side converter and bi-directional Buck-Boost converter are derived. The switching function model of grid-side converter and bi-directional Buck-Boost converter, the state equation model and transfer function model of bi-directional Buck-Boost converter are included. Thirdly, a coordinated control strategy for grid-side converters in D-PMSG WTGS and bi-directional Buck-Boost converters for storing and releasing electric energy from supercapacitors is proposed. The second order Generalized Integrator Phase-Locked Loop (SOGI-PLL) is used to detect the grid voltage. When the power network is normal, the grid-side converter adopts DC voltage outer loop based on voltage feedforward and current inner loop. Two-way Buck-Boost converter is controlled by current single closed loop, power outer loop combined with negative sequence voltage feedforward is used in grid-side converter, and bi-directional Buck-Boost converter is controlled by DC voltage outer loop and current inner loop. The simulation results in Matlab/Simulink environment show that the proposed coordinated control strategy can improve the fault traversal capability of D-PMSG WTGS. Fourthly, the power smoothing control of D-PMSG WTGS is studied. The wind speed power model is designed to simulate the state of wind turbine output fluctuating with the wind speed. In order to realize the grid connection power is relatively smooth, the grid voltage oriented control is used in the grid-side converter. Two-way Buck-Boost converter is controlled by single-loop current. The given value of active power is determined by the output power and its average value, and the results of the average power obtained by numerical averaging method and low-pass filtering method are compared and analyzed. The simulation results show that the supercapacitor can compensate the active power fluctuation of D-PMSG WTGS and make the active power connected to the grid relatively smooth and stable. Finally, the paper summarizes the full text and prospects for further research.
【学位授予单位】：内蒙古工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TM315;TM53

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