双路光伏并网系统损耗分析与效率优化

Loss Analysis and Efficiency Optimization of Two-string Photovoltaic Grid-connected System

确定光伏并网系统的效率优化方法应基于准确的损耗分析,开关器件作为初步建模对象为变换器的损耗模型提供了理论依据。为实现双路光伏系统进网功率的最大化,从开关损耗随直流母线电压变化的现象得到最优功率点(MPP)并设计改进的启停方案实现追踪,在追踪过程中依据电压条件适时启停Boost变换器,减小不必要的开关损耗提高效率。仿真与实验结果表明损耗模型能直观衡量系统效率,并且功率等级越高进网功率提高越显著。

Efficiency optimization of photovoltaic grid-connected system depends on accurate loss analysis and establishing loss model of switching device provides a theoretical basis for converter.In order to maximize the power supplied to grid,the maximum power point(MPP) is obtained from phenomenon that switching losses varies with direct current bus voltage and improved flowchart is designed to track.According to voltage condition each Boost converter is determined whether to operate or not in tracking to reduce unnecessary switching losses.Simulation and experimental results show that the loss model can measure efficiency more directly and the higher the power of system,the better the optimization effect.