光伏并网发电系统有功无功综合控制研究

发布时间：2018-05-07 00:11

本文选题：光伏发电 + MPPT　；参考：《西南交通大学》2014年硕士论文

【摘要】：面对世界能源危机和全球环境问题的日渐突出,以太阳能为代表的清洁可再生能源正受到越来越广泛的关注。一般情况下,并网光伏发电系统只向电网输送有功电能。但是,在夜间或者光照强度较弱的情况下,光伏并网发电系统将停止供电,设备利用率较低。针对这一问题,本文采用基于瞬时无功功率理论的光伏并网发电系统有功无功综合控制策略,在实现系统并网发电的同时对电网无功进行补偿。在不增加专用无功补偿设备的情况下,提高整个系统经济性。本文首先根据光伏电池的数学表达式,在仿真软件MATLAB/Simulink中建立模型。当外界温度、光照条件变化时,分析研究了光伏电池的输出电压、电流与输出功率之间的非线性特点。介绍了MPPT技术的实现原理,在传统模糊控制的基础上,将模糊规则自整定方法应用到光伏并网发电系统MPPT中,结合几种常见的MPPT方法,分别进行了对比仿真实现,结果表明基于模糊规则自整定MPPT方法在应对环境突变时也表现出良好的适应性。同时分析了PQ恒功率控制原理,搭建了PQ控制模型,验证了PQ控制的运行特性,实现了单位功率因数并网。其次,介绍了瞬时无功功率理论,研究分析了逆变器控制方法,对光伏并网发电系统无功补偿功能的实现进行了理论探讨。在此基础上,仿真验证了基于瞬时无功功率理论的谐波和无功电流检测技术的可行性,仿真结果表明无功补偿效果良好,响应迅速。搭建了系统仿真模型,构成了并网发电与无功补偿功能的光伏并网综合控制系统。模拟仿真了白天、夜晚两种工况条件下,光伏发电系统对配电网功率的影响。仿真结果表明,夜晚具有无功补偿功能的光伏并网发电系统,对于减少电网传输无功、增大系统利用率,提高本地负载电压水平具有明显效果。最后,研究了孤岛现象,介绍了光伏并网发电系统几种常用的主动式孤岛检测方法的实现原理及优缺点。搭建了基于滑模频率偏移法的孤岛检测模型,对孤岛状态进行检测与仿真控制。
[Abstract]:In the face of the world energy crisis and global environmental problems, clean and renewable energy, represented by solar energy, is receiving more and more attention. In general, grid-connected photovoltaic power generation system only conveys active power to the power grid. However, in the case of night or weak light intensity, PV grid-connected power system will stop power supply, equipment utilization is low. To solve this problem, the active and reactive power integrated control strategy of photovoltaic grid-connected generation system based on instantaneous reactive power theory is adopted in this paper, and the reactive power is compensated while the system is grid-connected. The economy of the whole system is improved without adding special reactive power compensation equipment. Firstly, according to the mathematical expression of photovoltaic cell, the model is established in the simulation software MATLAB/Simulink. The nonlinear characteristics of the output voltage, current and output power of the photovoltaic cell are analyzed when the external temperature and illumination conditions change. The realization principle of MPPT technology is introduced. On the basis of traditional fuzzy control, fuzzy rule self-tuning method is applied to photovoltaic grid-connected power generation system MPPT, and several common MPPT methods are compared and simulated respectively. The results show that the self-tuning MPPT method based on fuzzy rules has good adaptability to environmental mutation. At the same time, the principle of PQ constant power control is analyzed, the PQ control model is set up, the operation characteristic of PQ control is verified, and the unit power factor is connected to the grid. Secondly, the theory of instantaneous reactive power is introduced, the control method of inverter is analyzed, and the realization of reactive power compensation function of grid-connected photovoltaic system is discussed theoretically. On this basis, the feasibility of harmonic and reactive current detection technology based on instantaneous reactive power theory is verified by simulation. The simulation results show that reactive power compensation has good effect and rapid response. The system simulation model is set up, and the integrated control system of grid-connected photovoltaic system is constructed with the function of grid-connected generation and reactive power compensation. The influence of photovoltaic system on the power of distribution network is simulated under the conditions of day and night. The simulation results show that the photovoltaic grid-connected generation system with the function of reactive power compensation at night has obvious effect on reducing the reactive power transmission increasing the utilization ratio of the system and increasing the local load voltage level. Finally, the islanding phenomenon is studied, and the realization principle, advantages and disadvantages of several commonly used active islanding detection methods for grid-connected photovoltaic power generation system are introduced. An islanding detection model based on sliding mode frequency offset method is built to detect and simulate the island state.
【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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