单相光伏发电控制系统的研究

发布时间：2018-12-28 21:15

【摘要】：在能源枯竭与环境污染日益严重的今天,太阳能的开发和利用得到全世界的关注。光伏发电是太阳能利用的一种重要形式,具有广泛的应用前景和研究意义。论文以光伏并网发电系统为研究对象,对其控制技术进行了深入的研究。本论文研究的对象是光伏发电控制系统,其中光伏发电系统主要包括光伏电池模块、逆变器模块和并网模块。首先光伏电池主要是研究的是太阳光转换成电能的效率,这就要求对太阳光的最大功率点进行跟踪,当前的最大功率点跟踪的算法虽然能快速达到稳定,但是在光照强度发生变化时不能很好的对太阳光地进行跟踪,而且达到稳定时的波动较大,所以本文提出一种变步长的电导增量法,这种方法可以使外界光照强度发生变化是也能实现对太阳光的最大跟踪;其次是逆变器,当前对逆变器的电流跟踪方法有许多,但是存在许多的不足例如比例积分的控制电流方式含有非线性扰动信号效果不太明显,重复控制不能对外界出现的不定干扰进行合理控制,误差怕控制对整个系统的要求较高,所以本文采用加入电压前馈补偿的改进式SPWM控制方式来达到较好的效果;最后对孤岛效应的检测进行研究,目前对孤岛检测的方法主要存在孤岛检测的盲区,检测的效率低和检测的不稳定等缺点,所以本文采用主动频率偏移法来对孤岛效应进行检测。本文研究的结果显示采用变步长电导增量法要比传统的最大功率跟踪方法在开始时能很快达到稳定而且波动较小,在电流跟踪时采用前馈补偿的方法使得减小或消除电网电压对并网电流的影响,而对于孤岛检测本文的频率偏移法能很快检测到孤岛的发生。
[Abstract]:Nowadays, energy depletion and environmental pollution are becoming more and more serious, and the development and utilization of solar energy have been paid more and more attention all over the world. Photovoltaic power generation is an important form of solar energy utilization, which has wide application prospects and research significance. In this paper, the control technology of grid-connected photovoltaic power generation system is studied. The research object of this paper is photovoltaic power generation control system, which mainly includes photovoltaic cell module, inverter module and grid-connected module. First of all, the photovoltaic cell mainly studies the efficiency of converting solar light into electric energy, which requires tracking the maximum power point of solar light, although the current maximum power point tracking algorithm can quickly achieve stability. However, when the illumination intensity changes, the sunlight can not be tracked well, and the fluctuation is large when the illumination is stable, so this paper proposes a variable step length conductance increment method. This method can make the outside light intensity change and realize the maximum tracking of solar light. Secondly, the inverter, there are many current tracking methods for the inverter, but there are many shortcomings such as proportional integration of control current with nonlinear disturbance signal effect is not obvious. Repetitive control can not reasonably control the indeterminate disturbance, and the error fear control requires the whole system. So the improved SPWM control method with voltage feedforward compensation is adopted in this paper to achieve better results. Finally, the detection of islanding effect is studied. At present, the methods of islanding detection mainly have some shortcomings, such as the blind spot of islanding detection, the low efficiency of detection and the instability of detection, etc. So the active frequency offset method is used to detect the islanding effect. The results of this paper show that the variable step length conductance increment method is more stable and less fluctuating than the traditional maximum power tracking method at the beginning. In current tracking, feedforward compensation is used to reduce or eliminate the influence of grid voltage on grid-connected current, while the frequency offset method for islanding detection can detect the occurrence of isolated island quickly.
【学位授予单位】：安徽理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM615

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