基于增益调度自适应的并网逆变器的研究

发布时间：2018-02-09 10:41

本文关键词： 单相并网逆变器双闭环控制稳定性分析增益调度自适应　出处：《广西大学》2017年硕士论文　论文类型：学位论文

【摘要】：可再生能源发电技术不断发展,作为新能源发电装置和电网或负载的连接装置,并网逆变器的重要性愈加凸显。与传统大电网的阻抗很小不同,微电网是一个弱电网,其等效阻抗是不可以忽略并且实时变化的,当微电网阻抗发生变化时,传统固定控制器参数的并网逆变器难以保持理想的性能指标,甚至严重时导致系统不再稳定。本文采用增益调度自适应控制的策略设计并网逆变器的控制器,克服微电网阻抗变化对系统稳定性造成的影响。本文首先对并网逆变器涉及的控制技术和拓扑结构进行了对比,然后以全桥逆变器作为主电路拓扑,输出采用LCL滤波器,利用入网电流和电容电流进行双闭环控制来抑制LCL滤波器的谐振,驱动采用双极性SPWM控制方式,对单相并网逆变器系统进行数学建模,给出了系统的开环传递函数和输出阻抗表达式。对并网逆变器和微电网互联系统进行小信号建模,并给出系统稳定运行条件,对比分析了微电网阻抗和控制器参数等对系统稳定性的影响。以相位裕度为指标,对微电网阻抗进行了区间划分。搭建仿真模型,从仿真层面验证了阻抗区间划分的正确性和增益调度自适应控制的可行性。最后制作了一台单相并网逆变器试验样机,从实验层面验证了本文增益调度自适应控制策略的可行性。
[Abstract]:With the development of renewable energy generation technology, grid-connected inverters are becoming more and more important as new energy generation devices are connected to power grid or load. Different from traditional large power grid, micro-grid is a weak grid. The equivalent impedance can not be ignored and changed in real time. When the impedance of microgrid changes, it is difficult for the grid-connected inverter with fixed controller parameters to keep the ideal performance index. In this paper, the gain scheduling adaptive control strategy is used to design the controller of grid-connected inverter. In this paper, the control technology and topology of grid-connected inverter are compared, then the full-bridge inverter is used as the main circuit topology, and the output is based on LCL filter. The resonant of LCL filter is suppressed by double closed-loop control of the current into the grid and capacitor current. The single-phase grid-connected inverter system is modeled by using the bipolar SPWM control mode. The open loop transfer function and output impedance expression of the system are given. The small-signal modeling of grid-connected inverter and microgrid interconnection system is carried out, and the stable operating conditions of the system are given. The effects of impedance and controller parameters on system stability are compared and analyzed. Taking phase margin as an index, the impedance of microgrid is divided into sections, and the simulation model is built. The correctness of impedance interval partition and the feasibility of gain scheduling adaptive control are verified by simulation. Finally, a single-phase grid-connected inverter experimental prototype is made. The feasibility of the gain scheduling adaptive control strategy is verified by experiments.
【学位授予单位】：广西大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM464

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