局部阴影条件下基于支路串联电压源的光伏阵列结构设计

Structural Design of Photovoltaic Arrays Based on Series-voltage Source Under Partial Shading

局部阴影会导致光伏(photovoltaic,PV)阵列的输出功率下降,功率电压曲线呈现多个局部峰值情况,且光伏阵列的各个并联支路功率特性复杂化,没能完全工作在最大功率点(maximum power point,MPP),常规全局最大功率点追踪(global maximum power point tracking,GMPPT)方法效果不佳,因此有必要对光伏阵列结构进行优化,提高光伏系统的转换效率。在电路的串并联理论的基础上,对光伏阵列支路在局部阴影条件下的输出功率进行详细分析,采用支路串联电压源的光伏阵列结构,实现光伏支路最大功率的优化控制方法。通过对光伏支路进行电压补偿,使得每条支路都能工作在最大功率点,达到光伏阵列的最大功率输出。仿真和实验结果表明:通过对光伏支路串联电压源,提高了光伏阵列的输出功率。

Partial shading can make the output power of photovoltaic （PV） array decrease, and the output power-voltage curve will exhibit multiple local maximum power points. Moreover, the power characteristics of the PV array branch will be complicated, which cannot operate on the maximum power point （MPP） and normal global maximum power point tracking method （GMPPT） is not very effective, so it a needs optimize the PV array configuration under partial shading to improve the conversion efficiency. Based on the theory of series-parallel connection of electric circuit, the output power of the PV array branch under partial shading was analyzed in detail. A structure based on series-voltage source for PV array was adopted to realize the optimal control method of the maximum power branch. With voltage compensation to the branch, every branch in the array can operate on the MPP condition to obtain the maximum output power of the whole PV array. The simulation and experimental results show that the output power of the PV array under partial shading is method of series-voltage in the improved with the proposed PV array branch.