毕业论文--并网逆变器单周控制方法研究

《毕业论文--并网逆变器单周控制方法研究》由会员分享，可在线阅读，更多相关《毕业论文--并网逆变器单周控制方法研究（25页珍藏版）》请在毕设资料网上搜索。

1、 I 并网逆变器单周控制方法研究 摘 要 本文提出的设计和分析是针对主动和被动式的单相电压源功率控制逆变器的光伏并 网系统。文中主要研究其中的 DC-AC 变换，对单相并网逆变器做了总体设计，各个功能 模块单元也做了详细介绍。逆变电路采用单相全桥结构，对其工作状态做了分析，采用单 极性 SPWM 调制技术控制开关管的开通和关断，对主电路的器件选型给出了设计方法。 项目中的控制算法方法是采用基于矢量控制的坐标变换，将电流解耦为有功电流分量 和无功电流分量分别对电网功率进行控制方法。本研究的目的是控制电网的功率因数，提 高向电网传输的光伏转换电源整体效率，并降低逆变器相电流的畸变。在这项工作中，给

2、 出了详细的系统数学模型，讨论使用 Matlab / Simulink 软件对 6kW 的光伏系统并入 220V、 50HZ 电网模拟的结果。仿真结果表明，电网输入功率因数几乎是一致的，该系统的相电 流畸变率被降低，不同功率条件下的总谐波失真在 5%以内。 关键词：单相全桥逆变 SPWM（解耦） Matlab/Simulink 仿真 II Abstract This paper presents an alternative way for the current regulation of single-phase voltage-source dcac converters in dire

3、ctquadrature (dq) synchronous reference frames. In a dq reference frame, ac (time varying) quantities appear as dc (time invariant) ones, allowing the controller to be designed the same as dcdc converters, presenting infinite control gain at the steady-state operating point to achieve zero steady-st

4、ate error. The common approach is to create a set of imaginary quantities orthogonal to those of the real single-phase system so as to obtain dc quantities by means of a stationary-frame to rotating-frame transformation. The orthogonal imaginary quantities in common approaches are obtained by phase

5、shifting the real components by a quarter of the fundamental period. The introduction of such delay in the system deteriorates the dynamic response, which becomes slower and oscillatory. In the proposed approach of this paper, the orthogonal quantities are generated by an imaginary system called fic

6、tive axis, which runs concurrently with the real one. The proposed approach, which is referred to as fictive-axis emulation, effectively improves the poor dynamics of the conventional approaches while not adding excessive complexity to the controller structure. This paper presents the design and analysis of both the active and reactive power control of a single-phase voltage source inverter for grid-connected photovoltaic system. The proposed method is based on vector control of power by de