文档介绍：摘要
随着太阳能光伏发电产业在我国的推广和普及,国内对并网逆变器的需求必将越来越大,仅仅依靠进口已很难解决日益增长的巨大需要。因此,研制完全实用化、工程化的太阳能光伏并网逆变器成为该领域急需解决的问题,存在着广阔的市场前景。在此背景下,本文对正弦波并网逆变器的软硬件系统设计、控制算法研究和系统仿真等方面进行了深入探索。
首先介绍了国内外光伏发电产业的现状和广阔的前景,详细分析了并网逆变电路的拓扑结构和工作原理,讨论了全桥逆变电路直流侧和交流侧滤波器的设计思路,并推导出逆变电路关键参数的计算公式。
其次分析了单相电压控制和单相电流控制的不足,采用了基于DSP软件算法的电流电压双闭环控制技术。比较几种常用的光伏电池最大功率点跟踪方法,采用能够快速、准确跟踪光伏电池最大输出功率点的电导增量法来实现最大功率点的跟踪。
为了使并网电流和电网电压同频、同相,需要使用锁相环技术。本文详细分析了软件锁相环的原理,并结合实际系统设计方案和绘制软件流程图。
本文对孤岛效应的含义及相关标准进行了说明,分析了产生孤岛效应的原因和危害,证明了添加反孤岛保护的必要性,并分别对孤岛效应的主动和被动检测法进行了比较,用MATLAB仿真工具对本文所采用的主动频率偏移法进行了仿真验证。
最后,根据系统总体设计要求,对并网逆变器控制电路、驱动电路和保护电路进行了详细的设计,并制作了基于DSP控制的3kW光伏并网逆变器样机。通过实验表明,所采用的控制策略和设计的硬件电路能够满足设计要求,统可安全、稳定运行。
关键词光伏逆变器:DSP 最大功率点跟踪软件锁相环孤岛效应
Abstract
With the promotion and popularization of solar photovoltaic,there will be a greater demand for grid-connected inverters in our increasing demand for grid-connected inverters has e a problem which can not be solved only by means urgent problem to be solved is that the study and design of the photovoltaic grid-connectedinverters must be fully practical in use and in manufacture,and therefore there are desirable market prospects of the above-mentioned this paper,the grid-connected inverter is explored in the hardware design,control algorithm research,simulation and so on.
First of all,the present situation and broad prospect of photovoltaic industry at homeand abroad are topology and working principle of grid-connected inverter circuit are analyzed in the design ideas and processes of the filters on both DC and AC sides are discussed;moreover,the formulas of the key parameters of the maincircuit are derived.
Next,the current and voltage dual closed-loop control based on software algorithms of DSP is chosen by analyzing the deficiencies of voltage control and current arithmetic of incremental conductance of MPPT of grid-connected system realizes the tracking of MPPT paring with several methods of MPPT of grid-connec