光伏电池输出特性及其最大功率跟踪研究

Study on Output Characteristic of Photovoltaic Cell and Its Maximum Power Tracking

介绍了光伏电池工程实用数学模型,分析了光伏电池在任意温度和光照强度下的U-I、U-P输出特性。对扰动观察法进行改进并建立了最大功率跟踪模型(MPPT),与Buck-Boost电路结合使用通过PWM来获得控制信号以此来改变光伏电池的输出电压,能很好地实现光伏发电系统最大功率点的跟踪。最后运用Matlab的Simulink搭建了光伏电池仿真模型。仿真结果得出:虽然当光照强度稳定时,温度越高最大输出功率越小,当温度恒定时,光照强度越大最大输出功率越大;但当温度和光照强度同时变化时,起主要影响因素的依然是光照强度。仿真验证了改进扰动观察法比电导增量法更快速而精准地将输出功率稳定在一个固定值,为整个光伏及微网系统进一步研究提供参考价值。

This paper introduces the practical mathematical model of photovoltaic cell engineering,and analyzes the UI and U-P output characteristic of photovoltaic cells at any temperature and light intensity. Disturbance and observation method is improved and the model of maximum power point tracking（MPPT） is established. By combining with BuckBoost circuit,control signal can be obtained by PWM thus output voltage of photovoltaic cell will be changed,which makes it possible to achieve the tracking of maximum power point of photovoltaic power generation system. Finally simulation model of photovoltaic cell is established by Matlab and Simulink. The results showed that the higher the temperature is,the smaller the output power will be when the light intensity keeps constant and the output power is proportional to light intensity when the temperature is stable. If the temperature and the light intensity vary at the same time,it is the light intensity that plays a more important role. The improved disturbance and observation method can stabilize the output power at a certain value more quickly and accurately when being compared with incremental conductance method. And the simulation has verified the above conclusion. All of these are of great reference value to the study of photovoltaic system and micro-grid system.