电网不平衡条件下双馈型风机网侧变流器控制策略的研究

发布时间：2018-03-07 03:32

本文选题：网侧变流器　切入点：电网不平衡　出处：《燕山大学》2014年硕士论文　论文类型：学位论文

【摘要】：在世界各国大力发展的众多可再生能源中，风能因其储量大、分布面广等优良特性，受到了人们的广泛关注。我国风能资源主要集中于沿海与内蒙古等边疆地区，距离负荷中心较远，风场电网电压易出现波动、不平衡等状态。因此本文针对电网不平衡状态下基于双馈感应发电机(DFIG)的风力发电系统网侧变流器的控制策略进行了深入研究。本文首先介绍了电网同步技术，电网同步技术是DFIG风力发电系统实现并网运行需要解决的关键技术之一，其检测的准确性直接影响DFIG风力发电系统控制策略运行的效果。文中详细分析了2阶广义积分器锁频环的原理，将其应用于电网不平衡条件下电网电压频率的检测及正负序分量的分离。此外，对双2阶广义积分器锁频环进行改进，为其增加相位功能，并对其进行了仿真与实验分析。其次，对DFIG风力发电系统网侧变流器的模型及控制策略进行了分析研究。长期以来网侧变流器运行主要应用矢量控制，近年来直接功率控制以其控制结构简单、动态响应性能好等优点而受到越来越多的研究。本文分析了电网平衡及不平衡条件下网侧变流器的数学模型与基于滑模变结构的直接功率控制(SMC-DPC)策略，并详细介绍了滑模控制器的设计。在电网不平衡条件下，根据网侧变流器的运行状态设置了不同控制目标，并应用SMC-DPC对变流器进行了整流与逆变仿真与实验。除此之外，文中还通过仿真与实验对比分析了矢量控制与SMC-DPC。最后，，本文详细介绍了网侧变流器的硬件电路设计与dSPACE实时仿真系统，并给出了电网平衡、不平衡条件下电网同步实验和变流器整流与逆变实验的波形图。通过实验研究验证了本文采用的电网同步算法与控制策略的正确性和有效性。
[Abstract]:Among the many renewable energy sources vigorously developed in the world, wind energy has attracted extensive attention because of its excellent characteristics such as large reserves and wide distribution. Wind energy resources in China are mainly concentrated in the coastal areas, Inner Mongolia and other frontier areas. Because of the distance from load center, the voltage of wind field is prone to fluctuate and unbalance, so the control strategy of grid-side converter of wind power system based on doubly-fed induction generator (DFIGG) is studied in this paper. This paper first introduces the power grid synchronization technology, which is one of the key technologies to be solved for the DFIG wind power system to realize grid-connected operation. The accuracy of the detection directly affects the effect of the control strategy operation of DFIG wind power system. The principle of the frequency locking loop of the second order generalized integrator is analyzed in detail in this paper. It is applied to the detection of the voltage frequency and the separation of the positive and negative sequence components under the unbalanced condition of the power network. In addition, the frequency locking loop of the two-order generalized integrator is improved to increase the phase function, and the simulation and experimental analysis are carried out. Secondly, the model and control strategy of grid-side converter of DFIG wind power system are analyzed and studied. For a long time, vector control is mainly used in the operation of grid-side converter. In recent years, direct power control is simple with its control structure. In this paper, the mathematical model of grid-side converter and SMC-DPC-based direct power control strategy based on sliding mode variable structure are analyzed. The design of sliding mode controller is introduced in detail. Under the condition of unbalanced power network, different control targets are set according to the operating state of the grid-side converter, and the rectifier and inverter are simulated and tested by SMC-DPC. The vector control and SMC-DPC are compared and analyzed by simulation and experiment. Finally, the hardware circuit design and dSPACE real-time simulation system of grid-side converter are introduced in detail, and the power network balance is given. The waveform diagram of the power network synchronization experiment and the rectifier and inverter experiment under unbalanced conditions is presented. The correctness and effectiveness of the proposed synchronization algorithm and control strategy are verified by experimental research.
【学位授予单位】：燕山大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM46

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