高频隔离型准Z源光伏微逆变器的控制策略研究

发布时间：2018-05-07 20:48

本文选题：光伏发电 + 隔离准Z源逆变器　；参考：《重庆理工大学》2017年硕士论文

【摘要】：21世纪以来,随着传统的三大能源枯竭,以及传统能源在使用过程中所带来的污染,导致人类向绿色新能源的方向发展。其中太阳能以其储量之大,绿色无污染,分布范围广泛等优势,成为绿色新能源的发电趋势。光伏并网发电的核心是并网逆变器,传统的并网逆变器属于集中逆变,这将导致其具有抗阴影能力差、直流链母线电压较高、系统损耗大,效率较低,易出现故障等缺点,为此提出微型逆变器,来解决上述问题。本文首先分析了光伏微型逆变器在国内外的发展背景以及研究现状,并对光伏组件的输出特性进行分析;在比较了常用的最大功率点跟踪算法的基础之上,对扰动观察法进行了改进,并通过仿真验证改进的算法具有更氋的跟踪速度。然后分析对比了几种光伏逆变电路拓扑结构,针对它们所存在的缺点,引入了高频隔离型准Z源拓扑结构,并对Z源类逆变器的拓扑结构,工作原理以及发展进行描述;并选择简单升压SPWM调制技术作为本文的调制策略;其次重点研究了隔离准Z源逆变器的控制策略,在小信号模型的基础上,对其系统控制结构分析,通过对副边电容电压与并网电流的双闭环控制来实现系统的并网控制。针对传统PI调节器在对并网电流控制时,无法实现无静差跟踪以及无法解决电网扰动的问题,本文引入准比例谐振调节器来对并网电流进行控制,并从理论上对两种控制器的性能进行比较分析,得出准PR调节器能够很好的消除稳态误差,且抗电网扰动能力要强于PI调节器。最后以300W为例在saber软件中建立光伏并网逆变器模型,对本文所设计的控制器进行仿真验证,同时结合RT-LAB实验平台对所搭建的半实物进行实验研究,结果表明设计控制策略的有效性。
[Abstract]:Since the 21st century, with the depletion of the three traditional energy sources and the pollution caused by the use of the traditional energy, the human beings are developing to the direction of green new energy. Solar energy has become the trend of new green energy generation because of its large reserves, no pollution, wide distribution and other advantages. The core of grid-connected photovoltaic power generation is grid-connected inverter. The traditional grid-connected inverter belongs to centralized inverter, which will lead to its poor anti-shadow ability, high voltage of DC link bus, large system loss, low efficiency, easy to appear faults and so on. For this reason, a micro inverter is proposed to solve the above problems. Firstly, this paper analyzes the development background and research status of photovoltaic miniature inverter at home and abroad, and analyzes the output characteristics of photovoltaic module, based on the comparison of common maximum power point tracking algorithm. The disturbance observation method is improved, and the simulation results show that the improved algorithm has better tracking speed. Then, the topology of several photovoltaic inverter circuits is analyzed and compared. Aiming at their shortcomings, the high-frequency isolated quasi-Z-source topology is introduced, and the topology structure, working principle and development of Z-source inverter are described. The simple boost SPWM modulation technique is chosen as the modulation strategy in this paper. Secondly, the control strategy of isolated quasi Z source inverter is studied. Based on the small signal model, the control structure of the system is analyzed. The system grid-connected control is realized by double closed loop control of secondary capacitor voltage and grid-connected current. In view of the problem that the traditional Pi regulator can not realize the static error tracking and solve the problem of grid disturbance when the traditional Pi regulator controls the grid-connected current, the quasi-proportional resonant regulator is introduced to control the grid-connected current. The performance of the two controllers is compared and analyzed theoretically. It is concluded that the quasi-PR regulator can eliminate the steady-state error well and the anti-disturbance ability of the power network is better than that of the Pi regulator. Finally, the model of photovoltaic grid-connected inverter is established in saber software with 300W as an example, and the controller designed in this paper is simulated and verified. At the same time, the hardware-in-the-loop experiment is carried out with the RT-LAB experimental platform. The results show that the control strategy is effective.
【学位授予单位】：重庆理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM464

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