交错并联反激式光伏并网微型逆变器设计

发布时间：2018-06-07 04:38

本文选题：光伏并网逆变器 + 交错并联反激变换器　；参考：《中北大学》2017年硕士论文

【摘要】：太阳能作为无污染的可再生能源正在被世界各国广泛的开发和利用,分布式光伏并网发电是太阳能利用的热点之一,其特点是每块光伏电池板连接一块微型逆变器,而微型逆变器是光伏发电系统的核心设备,可将光伏板输出的直流电转换为与电网同频同相的交流电并入电网。光伏并网逆变器输出的电能质量会直接影响电网的稳定,因此提高逆变器的转换效率和发电质量至关重要。本文首先根据光伏电池的仿真模型,分析了不同温度和光照强度时的特性曲线,提出改进型变步长扰动观察法解决了传统扰动观察法在跟踪速度与控制精度无法平衡的矛盾,实现了光伏发电系统的最大功率点跟踪。设计了前级为交错并联反激变换器,后级为全桥电路的光伏并网微型逆变器,分析了反激式微型逆变器在各工作模式下的特性和元器件应力,得出系统控制策略为连续导通模式时更加稳定可靠,在反激变换器中加入了有源钳位电路不仅可以提高DC-DC的转换效率,还能实现MOSFEF管的零电压开关,采用了主动移频检测法能高效检测光伏并网逆变器的孤岛效应。在Matlab/Simulink中搭建了交错并联反激式光伏发电系统仿真模型,验证控制算法能够满足光伏并网微型逆变器的性能要求。最后,计算硬件电路的主要元器件参数、选择合适元器件型号,设计了以Microchip公司的dsPIC33FJ16GS504数字信号控制器为控制核心的有源钳位交错并联反激式光伏并网微型逆变器样机,并通过软件实现控制算法、系统状态机和软件锁相环设计。在实验室搭建了200W的光伏并网微型逆变器实验平台,进行了并网实验、孤岛检测和逆变器转换效率统计。并网电流总谐波和孤岛检测反应时间均符合国家规定的相关标准,逆变器电能转换效率也较为理想。本文通过仿真波形和实验波形充分验证了设计的光伏并网逆变器具有可行性。
[Abstract]:Solar energy, as a pollution-free renewable energy, is widely developed and utilized in the world. Distributed photovoltaic grid-connected power generation is one of the hot spots in solar energy utilization, and its characteristic is that each photovoltaic panel is connected with a miniature inverter. The miniature inverter is the core equipment of the photovoltaic power generation system, which can convert the direct current output of the photovoltaic panel into alternating current with the same frequency and the same phase as the grid. The output power quality of photovoltaic grid-connected inverter will directly affect the stability of the power grid, so it is very important to improve the conversion efficiency and generation quality of the inverter. In this paper, according to the simulation model of photovoltaic cell, the characteristic curve of different temperature and light intensity is analyzed, and the improved variable step size perturbation observation method is proposed to solve the contradiction between the tracking speed and the control precision of the traditional disturbance observation method. The maximum power point tracking of photovoltaic system is realized. A photovoltaic grid-connected miniature inverter with interleaving parallel flyback converter and full bridge circuit is designed. The characteristics of flyback miniature inverter and the stress of components are analyzed. It is concluded that the system control strategy is more stable and reliable in continuous on-mode. Adding active clamp circuit to the flyback converter can not only improve the conversion efficiency of DC-DC, but also realize the zero-voltage switch of MOSFEF transistor. The active frequency shift detection method can efficiently detect the islanding effect of photovoltaic grid-connected inverter. The simulation model of staggered parallel flyback photovoltaic power generation system is built in Matlab/Simulink to verify that the control algorithm can meet the performance requirements of photovoltaic grid-connected miniature inverter. Finally, the main component parameters of the hardware circuit are calculated and the appropriate type of components is selected. A prototype of the active clamp staggered parallel flyback photovoltaic grid-connected miniature inverter with Microchip's dsPIC33FJ16GS504 digital signal controller as the control core is designed. Control algorithm, system state machine and software phase locked loop are designed by software. An experimental platform of 200W photovoltaic grid-connected miniature inverter is set up in the laboratory. The grid-connected experiment, islanding detection and inverter conversion efficiency statistics are carried out. The total harmonics of grid-connected current and the detection time of isolated island are in accordance with the relevant national standards, and the inverter power conversion efficiency is also ideal. The feasibility of the designed photovoltaic grid-connected inverter is fully verified by simulation and experimental waveforms.
【学位授予单位】：中北大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM464

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