基于内高频环的并网三相光伏逆变器的研究和实现-电力电子与电力传动专业论文.docx

万方数据 万方数据 摘要 摘要 传统能源的日益枯竭及人类社会对能源需求的不断增长，使得人们不得不寻 求低污染、低排放的可再生能源构成合理的能源组成结构。光伏发电是通过光生 伏打效应对太阳能直接利用的新能源，随着当前不断发展的电力电子技术及控制 技术，及对光伏发电系统日益深入的研究，光伏发电系统近年来在全球范围内获 得了飞速的发展。 本文主要以 10KW 内高频环并网三相逆变器的研究和实现为基础，就并网光 伏逆变器中的一些关键技术展开论述。主电路的拓扑采用的是内高频环脉冲直流 环（HFPDC-link）与三相半桥逆变的结构。内高频环脉冲直流环本质上是有隔离 作用的 DC/DC 正激拓扑结构，由于有高频变压器的作用，使得电路的占空比得到 扩展，可以工作在大于 0.5 占空比条件下。该结构可以使得后级三相逆变电路在采 用优化的空间矢量控制方法下取得零电压开关（ZVS）的效果。逆变器效率、功率 密度及可靠性的提升是一个系统的工程，本文主要从在高频工作时减少开关器件 的动作次数及零电压开关上来提高效率，并论述减小变压器器体积的内高频结构， 通过采用解耦双同步参考系锁相环来使并网逆变器与电网同步，从而提高系统的 可靠性。逆变器的控制器采用 TMS320F2812，通过该 DSP 的强大功能实现单控制 器对系统的控制功能。主电路部分将通过 PLECS 进行仿真，根据仿真结果改进参 数然后进行实验验证分析。 通过理论分析和实验验证，光伏逆变器的效率获得提高，在同等功率条件下 的有变压器并网光伏逆变器中，系统的功率密度也有显著提高。 关键字：并网光伏逆变器，脉冲直流内高频环，电网同步 I ABSTRACT ABSTRACT As the traditional energy especially the fossil energy depletion, and the huge global incremental requirement of the energy resource, make the human society have to find a reasonable energy mix, the sustainable energy which is low-carbon and low-emission is the best choice. Photovoltaic effect is the direct use of the solar ray to get electricity, as the development of the power electronics and control theory which applied to this field, the photovoltaic system research rapidly developed worldwide. This paper is mainly based on the study and implementation of the 10KW high frequency DC-link grid connected inverter to research the key technology of the grid connected PV inverters. The main circuit topology is high frequency pulse DC link and three phase half bridge. In fact the High frequency pulse DC link circuit equal to the isolated forward DCDC converter, which duty circle is extended and could worked on the duty circle greater than 0.5. This structure with the next stage which driven by optimized SVPWM could implement the combined ZVS function. The improvement of the efficiency, power density and reliability of PV inverters are systematic work. This paper will discuss the method to reduce the power switch on and off behavior to reduce the loss caused by power s