基于序阻抗的AC-DC储能变换器的建模及分析

发布时间：2019-06-11 20:35

【摘要】：随着新能源技术的开发和利用,双向变换器作为储能装置和电网连接的纽带,其性能直接关系到整个储能系统的可靠性以及精确性。由于技术的发展和需求的提升,分布式电力系统的稳定性问题变得越来越突出,因此,研究怎么解决双向变换器接入电网后的稳定性问题具有重要的实际意义。本文介绍了三相不控整流器和三相PWM整流器的阻抗建模方法。通过把三相系统分解为两个互相解耦的序子系统,然后根据谐波线性化的概念,利用分析型映射函数来描述电压和电流的转移,推导出各序子系统的正序和负序阻抗模型。本文着重分析了三相PWM整流器的序阻抗模型,对推导出的整流器交流侧的输入阻抗模型和电网侧的输出阻抗模型应用奈奎斯特稳定性判据,来分析三相交流系统的动态交互作用,并通过仿真实验来验证推导出的数学模型的有效性。同时也分析了直流母线电容的大小对直流母线电压稳定性的影响,并提出通过在直流母线上增加无源阻尼来稳定直流母线电压,通过仿真展示了当RC阻尼器接入后,直流母线电压的变化。最后分析了锁相环(PLL)对变换器稳定运行的影响,以基本的SPF-PLL为例,对其进行了小信号建模,并利用主电路参数对dq电流控制下的序阻抗模型进行了验证。
[Abstract]:With the development and utilization of new energy technology, bidirectional converter, as the link between energy storage device and power grid, its performance is directly related to the reliability and accuracy of the whole energy storage system. With the development of technology and the improvement of demand, the stability of distributed power system has become more and more prominent. Therefore, it is of great practical significance to study how to solve the stability problem of bidirectional converter connected to the power grid. In this paper, the impedance modeling methods of three-phase uncontrolled rectifier and three-phase PWM rectifier are introduced. By decomposing the three-phase system into two decoupling ordered subsystems, and then according to the concept of harmonic linearization, the analytical mapping function is used to describe the transfer of voltage and current, and the positive and negative sequence impedance models of each ordered subsystem are derived. In this paper, the sequence impedance model of three-phase PWM rectifier is analyzed. The Naiquist stability criterion is used to analyze the dynamic interaction of three-phase AC system by applying the input impedance model on the AC side of the rectifier and the output impedance model on the power grid side, and the effectiveness of the deduced mathematical model is verified by simulation experiments. At the same time, the influence of DC bus capacitance on DC bus voltage stability is analyzed, and it is proposed to stabilize DC bus voltage by adding passive damping to DC busbar. Simulation results show the change of DC bus voltage when RC dampers are connected. Finally, the influence of phase-locked loop (PLL) on the stable operation of the converter is analyzed. Taking the basic SPF-PLL as an example, the small signal modeling is carried out, and the sequence impedance model controlled by dq current is verified by the main circuit parameters.
【学位授予单位】：广西大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TM46

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