双三电平变流器馈电的开绕组BDFG直接功率控制研究

发布时间：2018-10-29 23:08

【摘要】：近年来,在我国经济迅速发展的背景下,能源需求量不断增大,传统的化石资源又存在利用率不足以及开采过度等问题。风能作为在地表大量存在的清洁型可再生能源,在国内外受到了广泛关注。目前在风力发电系统中主要采用永磁同步发电机和双馈感应发电机,前者存在需要全功率变流、成本高等问题,后者存在需要定期维护、控制方法复杂等问题。无刷双馈发电机则是一种低成本且不需要频繁维护的新型发电机,特别适合应用在风力发电系统中。本文以国家自然科学基金项目“复合转子开绕组无刷双馈风力发电机及其直接功率控制策略”(项目批准号:51277124)为背景,以开绕组无刷双馈发电机为研究对象,提出研究一种基于开绕组双三电平变流器馈电的直接功率控制方法,以实现开绕组无刷双馈风力发电机系统的功率跟踪控制。本文在以下方面进行重点研究:首先,分析了无刷双馈发电机的工作原理及其三种运行方式,对在三种运行模式下的绕组间功率流向问题进行了深入研究。在此基础上,建立了无刷双馈发电机在旋转坐标系下的数学模型,并搭建了仿真模型对其运行性能进行了仿真研究。其次,将无刷双馈发电机的控制绕组设计成开绕组结构,两端分别与一个三电平变流器相连。针对这种拓扑结构,提出采用直接功率控制方法,以实现功率跟踪控制。该种控制方法具有功率响应速度快,不需要复杂的坐标变换,计算量小等优点。此外分析了开绕组无刷双馈发电机系统中双三电平变流器输出的空间电压矢量,并进行了比较,为直接功率控制系统的设计和空间电压矢量选择表的重新制定提出依据。最后,根据双三电平变流器输出电压矢量的不同特点,对直接功率控制方法进行改进,分别对12扇区、24扇区和不对称36扇区三种不同扇区划分方法下基于功率误差比较的直接功率控制方法进行设计和对比分析。在Matlab/Simulink环境下,对基于三种扇区划分方法的开绕组无刷双馈风力发电机直接功率控制系统在转速和功率给定发生变化时的三种运行方式进行仿真研究,并对三种方法在控制精度、功率波动等方面的控制效果进行对比分析。仿真结果表明这三种方法均可满足对有功功率和无功功率的控制要求,并可根据不同的应用环境选择不同的方法。
[Abstract]:In recent years, under the background of rapid economic development in China, the energy demand is increasing, and the traditional fossil resources have some problems, such as insufficient utilization ratio and over-exploitation. Wind energy, as a kind of clean renewable energy, has been paid more and more attention at home and abroad. At present, permanent magnet synchronous generator (PMSG) and doubly-fed induction generator (DFI) are mainly used in wind power generation system. The former has the problems of full power conversion and high cost, while the latter needs regular maintenance and complex control methods. Brushless doubly-fed generator is a new type of generator with low cost and no frequent maintenance. It is especially suitable for wind power generation system. In this paper, taking the project of National Natural Science Foundation, "Brushless Doubly-fed Wind Generator with compound rotor Open Winding and its Direct Power Control Strategy" (Project Grant No. 51277124) as the background, the open winding brushless doubly-fed generator is taken as the research object. A direct power control method based on open-winding double-three-level converter feed is proposed to realize the power tracking control of open-winding brushless doubly-fed wind turbine system. This paper focuses on the following aspects: firstly, the working principle and three operation modes of the brushless doubly-fed generator are analyzed, and the power flow direction between the windings under the three operation modes is deeply studied. On this basis, the mathematical model of brushless doubly-fed generator in rotating coordinate system is established, and the simulation model is built to study the performance of brushless doubly-fed generator. Secondly, the control windings of the brushless doubly-fed generator are designed as open windings, each of which is connected to a three-level converter. Aiming at this topology, a direct power control method is proposed to realize power tracking control. This control method has the advantages of fast power response, no complicated coordinate transformation and less computation. In addition, the output space voltage vector of the double three-level converter in the open-winding brushless doubly-fed generator system is analyzed and compared, which provides the basis for the design of the direct power control system and the reformulation of the space voltage vector selection table. Finally, according to the different characteristics of the output voltage vector of the two-three-level converter, the direct power control method is improved. The direct power control method based on power error comparison is designed and compared with three different sector partitioning methods for 24 sector and asymmetric 36 sectors. In Matlab/Simulink environment, three operation modes of the direct power control system of open-winding brushless doubly-fed wind turbine based on three sector partition methods are simulated when the speed and power are given. The control effect of the three methods in the aspects of control precision and power fluctuation is compared and analyzed. The simulation results show that the three methods can meet the control requirements of active power and reactive power, and can choose different methods according to different application environments.
【学位授予单位】：沈阳工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM46;TM315

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