分布式光伏电源并网技术研究

发布时间：2018-12-14 06:21

【摘要】：进入二十一世纪以来,石油价格日趋上涨,全球能源供应持续紧张,怎样合理开发和有效的利用绿色能源已经成为全世界迫在眉睫的重要课题。太阳能作为一种绿色能源正在逐渐发挥出它的优势,光伏发电并网关键技术的发展也会起到更大的推进作用。光伏电源大量接入对电网带来了诸多不良影响,微网系统的出现可以缓解这一问题,因而成为了各国的研究热点。本文以三相光伏发电系统的控制策略为研究对象,以SVPWM调制方式为基础,并网DG采用最大功率跟踪的PQ电流解耦与PI控制相结合的控制方法,对组网DG的控制以下垂控制为基础,通过引入下垂额定点调整环实现对组网DG的PQ控制,并完成了两种控制的平滑切换。首先,本文分析了具有不同阵列形式的光伏发电系统优缺点。列举并对比了国内外光伏并网标准,简要介绍了最大功率点跟踪方法,并对本文采用的扰动观察法进行了仿真验证。其次,设计了电压外环电流内环及PI控制相结合的并网DG控制模式,可使得电流波形具有更好的稳定性,谐波含量更少,逆变器输出电流可以实现与电网电压的同频同相,进而保障了有功功率的全负荷输出。本文搭建了由组网DG和并网DG构成的微网系统,仿真验证了微网系统能够稳定运行。针对无功环流问题,本文采用在下垂控制中对线路压降进行补偿以改善无功环流问题。通过对控制方式切换,可使DG运行在不同工作模式下。最后,设计了基于DSP的光伏并网系统的硬件,并设计了相关软件流程图。
[Abstract]:Since entering the 21 century, the oil price is rising day by day, the global energy supply continues to be tight, how to rationally develop and utilize the green energy effectively has become an urgent and important issue all over the world. As a kind of green energy, solar energy is gradually exerting its advantages, and the development of key technology of photovoltaic power grid will play a more important role. A large number of photovoltaic power supply access to the grid has brought a lot of adverse effects, the emergence of micro-grid systems can alleviate this problem, so it has become a research hotspot around the world. In this paper, the control strategy of the three-phase photovoltaic power generation system is studied. Based on the SVPWM modulation mode, the grid-connected DG adopts the maximum power tracking PQ current decoupling and PI control method. The control of DG is based on droop control, and the PQ control of DG is realized by introducing droop rating adjustment loop, and the smooth switching of two kinds of control is completed. Firstly, the advantages and disadvantages of photovoltaic power generation systems with different arrays are analyzed. The domestic and foreign photovoltaic grid-connected standards are listed and compared, the maximum power point tracking method is briefly introduced, and the perturbation observation method used in this paper is simulated and verified. Secondly, the grid-connected DG control mode combining voltage outer loop current inner loop and PI control is designed, which makes the current waveform have better stability, less harmonic content, and the output current of inverter can realize the same frequency and phase with the grid voltage. Thus, the full load output of active power is guaranteed. In this paper, a microgrid system composed of networked DG and grid-connected DG is built, and the simulation results show that the microgrid system can run stably. In order to improve the reactive circulation problem, the voltage drop of the line is compensated in droop control. By switching the control mode, the DG can run in different working modes. Finally, the hardware of photovoltaic grid-connected system based on DSP is designed, and the related software flow chart is designed.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM615

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