【作者】 文劲松；

【导师】 戴瑜兴；

【作者基本信息】 湖南大学 ， 电路与系统， 2007， 硕士

【摘要】 随着“绿色环保”概念的提出,以解决电力紧张,环境污染等问题为目的的新能源利用方案得到了迅速的推广,这使得研究可再生能源回馈电网技术具有了十分重要的现实意义。如何可靠地、高质量地向电网输送功率是一个重要的问题,因此在可再生能源并网发电系统中起电能变换作用的逆变器成为了研究的一个热点。本文主要以单相并网系统为研究对象,对并网系统的拓扑结构、控制策略、参数的选择、并网实验等方面作了详细的分析和研究,主要内容有:(1)研究了可再生能源开发的前景及并网逆变器的应用,阐述了逆变系统主体电路拓扑结构及原理,给出了直流侧和交流侧滤波器的设计思路,并导出了主体电路关键参数的计算公式。(2)针对逆变器并网工作的特点,给出了基于DSP的改进型SPWM电流跟踪控制策略,建立了系统控制的数学模型,确定了以PI闭环调节为控制核心,同时为了使输出电流控制达到较好的效果,还采用了一系列较为先进的辅助控制算法,其中电压前馈补偿控制抵消了市电对并网电流的影响;预测算法消除了采样过程中器件和原理性的误差,使采样值更逼近真实值;异步变频锁相算法能实现并网电流与市电电压同频同相,保证了逆变器以高功率因数输出。(3)对并网逆变器控制系统的软硬件进行了分块设计:对DSP主控芯片TMS320LF2407A的子模块资源和中断优先级进行了合理分配,利用其内部的CAP捕获接口设计出快速可靠的逆变系统软件锁相控制环,利用其SCI异步串行通信接口实现了逆变器的人机交互功能,利用其内嵌的CAN控制模块实现了逆变器的并机通信功能;同时对逆变系统的PWM输出接口、逆变驱动、A/D转换、保护控制及信号检测等模块的也进行了详细地分析和设计;最后对控制系统的程序按功能的区别进行了模块化编写。(4)根据系统总体设计要求,开发了并网逆变器样机,对其硬件电路及软件程序进行了分模块调试,给出了实验结果并对实验数据进行了分析。通过对并网逆变器样机测试表明,其直流输入、交流输出、功率因数、并网电流THD以及逆变效率等技术性能指标均达到或优于设计标准要求,实现了可再生能源以高功率因数回馈电网。样机系统运行稳定可靠,达到了预期的设计目标。更多还原

【Abstract】 With the concept of "Green and Environmental Protection" was proposed, all kinds of new energy exploitation program are in the rapid promotion, which is in order to solve the power shortage, pollution and other issues. It makes exploring renewable energy feedback the grid technology has a very important practical significance. How to deliver power into the grid reliably and quality is an important problem, the inverter that can transform the electrical energy in the system of the renewable resource to be fed into the grid is becoming one of the hot points in international research. This paper focuses on single-phase grid-connected system. The topology, control strategy, parameter selection and grid-connected experiment of grid-connected system are analyzed and studied in detail. The main contents are as follows:Firstly, the research current situation of grid-connected inverter and the development prospect of renewable energy are introduced, and then analyses main circuit topologies structure and principle of grid-connected inverter. The designing ideas and processes of the filters on both DC and AC sides are studied in this paper, and the formulas of the key parameters of the main circuit are derived and given out.Secondly, this paper aims at the character of grid-connected inverter, has proposed an improved SPWM current tracking control strategy based on DSP. The mathematical model of control system are established, it has ascertained PI closed-loop regulation for controlling core. Meanwhile, in order to control the output current to good effect, the system adopts a series of advanced and assistant control algorithms. Voltage feedforward compensation offsets the influence of the grid for the output current of the inverter. Prediction algorithm eliminates the errors of sampling process and designing principle, so that the sampling result and the real value are more approximation. Asynchronous varying-frequency modulation algorithm can enable the output current of the inverter and the Voltage of the grid with the same frequency and phase, it ensures that the inverter output in high power factor.Thirdly, this paper designs software and hardware of grid-connected inverter system respectively. It distributes sub-block resource and IPRI of the main control chip TMS320LF2407A properly, uses inner CAP capture interface of DSP to design a fast and reliable software PLL of inverter system. Otherwise, it uses SCI asynchronism serial communication interface to perform man-machine interaction function and uses the embedded CAN control block to perform muti-system communication function. In addition, it analyses and designs the PWM output interface, inverting drivers, A/D change, protected control and self-checking of the inverter system. The programs of different function block in control system are given at last.Finally, under the system design requirements, and developed an inverter prototype, its hardware and software were experimented and debugged, and the experimental results and data were given out.Through the inverter prototype tests show that its DC input, AC output, power factor, inverter efficiency, the THD of the grid-connected current, and other areas of technical indicators are attained or better than design standards require, the inverter accomplishes the feedback of the renewableenergy to the utility line in high power factor. The prototype can work stably and achieve the expected goals.更多还原