光伏发电系统发电效率研究

发布时间：2018-03-25 07:25

本文选题：太阳辐射　切入点：光伏阵列　出处：《北京交通大学》2014年硕士论文

【摘要】：由于能源危机和环境恶化问题的日益加重,太阳能光伏发电凭借其特有优势得到了快速发展,但光伏发电相对于其它可再生能源存在发电成本偏高和发电效率偏低的问题,因此对这两大问题的研究将会极大地促进光伏发电应用的推广。本文以对光伏发电系统进行发电量估算和效率优化为目的,建立了完整的光伏发电系统模型,主要包括太阳辐射、光伏电池、不同跟踪下的光伏阵列、电缆、汇流箱和逆变器效率模型。在实际中,影响光伏阵列发电量的主要因素包括阵列的安装角度、遮挡、电缆和弱光。本文基于上述所建立的光伏发电系统模型研究了建筑物表面朝向和倾角对光伏组件所接受到的年辐照量的影响,并在MATLAB中建立了可模拟光伏组件反向特性的工程适用模型,针对光伏组件、光伏组串、光伏阵列在局部遮挡下的输出特性、电缆失配和弱光条件所导致的发电量损失进行了详细分析,通过仿真得出了不同阵列规模下的阴影最优分布规律和组串式MPPT的适用条件,为光伏发电系统效率优化奠定了理论基础。然后基于以上理论分析提出了局部遮挡下的光伏阵列配置优化方案和改进后的群控拓扑方案,光伏阵列配置优化方案可在不增加光伏发电系统控制难度的条件下降低阴影对阵列发电量的影响,改进后的群控拓扑优化方案不仅能提高弱光下的发电效率、拓宽阵列的有效输出功率范围,同时能保证强光下各个光伏阵列单元独立运行,缩小阴影影响范围。最后在LabVIEW中建立了光伏发电系统的发电量和发电效率估算系统,该系统可以对光伏电站进行有效后评估,其中间输出量如太阳高度角、方位角、跟踪装置的跟踪角等参数对于后续研究具有重要意义,且该系统实现了界面化和模块化,具有解算速度较快、适用性较强的优点。并以鄯善地区20MW为例进行了仿真分析,仿真得出平单轴跟踪、斜单轴跟踪、竖直单轴跟踪和双轴跟踪的最佳跟踪角范围,通过比较采用各种跟踪方式所增加的成本回收年数确定了鄯善地区的最佳跟踪方式。
[Abstract]:Because of the worsening of energy crisis and environmental degradation, solar photovoltaic power has been developed rapidly because of its unique advantages. However, compared with other renewable energy, photovoltaic power generation has the problems of high power generation cost and low power generation efficiency. Therefore, the research on these two problems will greatly promote the application of photovoltaic power generation. In order to estimate the power generation and optimize the efficiency of photovoltaic power generation system, a complete photovoltaic system model is established in this paper. It mainly includes solar radiation, photovoltaic cells, photovoltaic arrays, cables, converters and inverter efficiency models under different tracking conditions. In practice, the main factors that affect the power generation of photovoltaic arrays include the installation angle of the array, occlusion, Based on the model of photovoltaic power system established above, the influence of building surface orientation and inclination on the annual irradiance received by photovoltaic modules is studied in this paper. An engineering applicable model is established in MATLAB to simulate the reverse characteristics of photovoltaic module. The output characteristics of photovoltaic module, photovoltaic array and photovoltaic array under local occlusion are discussed. The power loss caused by cable mismatch and weak light condition is analyzed in detail. By simulation, the optimal distribution law of shadow and the suitable condition of MPPT with different array size are obtained. It lays a theoretical foundation for the efficiency optimization of photovoltaic power generation system. Then, based on the above theoretical analysis, the optimized configuration scheme of photovoltaic array under local occlusion and the improved group control topology scheme are proposed. Photovoltaic array configuration optimization scheme can reduce the influence of shadow on array power generation without increasing the control difficulty of photovoltaic system. The improved group control topology optimization scheme can not only improve the generation efficiency under weak light. The effective output power range of the array can be widened, and each photovoltaic array unit can be operated independently under strong light, and the shadow influence range can be reduced. Finally, a system for estimating the power generation and generation efficiency of photovoltaic power generation system is established in LabVIEW. The system can be used for effective post-evaluation of photovoltaic power station, and its intermediate output is such as solar height angle, azimuth angle, and so on. The tracking angle and other parameters of the tracking device are of great significance for the follow-up research, and the system realizes interfacial and modularization, which has the advantages of fast calculation speed and strong applicability. The simulation analysis is carried out by taking 20MW in Shanshan area as an example. The optimal tracking angle range of flat uniaxial tracking, oblique uniaxial tracking, vertical uniaxial tracking and biaxial tracking is obtained by simulation. The optimal tracking mode in Shanshan area is determined by comparing the cost recovery years increased by various tracking methods.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM615

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