嵌入式智能光伏模块的最大功率输出统一控制

Application of Unified Output MPPT Control in DMPPT PV Systems

传统的太阳能系统经常会因为实际应用环境中的不匹配问题和光照不均现象而影响效率。分布式最大功率跟踪(distributed max power point tracking,DMPPT)概念的提出有效地抑制了这种影响。在分布式最大功率跟踪的基础上,该文提出一种嵌入式智能光伏模块(sub-panel MPPT converter,SPMC),利用非隔离的DC-DC变换器替代传统太阳能板接线盒中的旁路二极管,通过输出侧统一的最大功率计算单元对输入侧进行的指令信号控制,可以有效地消除太阳能板因为不匹配问题所带来的能量损失。文中首先对所提出智能光伏模块的拓扑结构进行分析、比较。然后以BUCK型的嵌入式智能光伏模块提出统一输出最大功率跟踪控制策略,这种控制策略在保证输出功率最大化的前提下,优化了系统模块,有效降低了系统控制复杂度和装置成本。最后,文章通过实验验证了所提出的概念和控制方法。

Due to mismatch cases,PV systems frequently suffer disproportionate impacts on energy generation.Distributed maximum power point tracking（DMPPT） is hereby proposed by academia to remedy the issues.As an advanced version of DMPPT,this paper proposes an MPPT converter that connects to each PV cell string,called a sub-panel MPPT converter（SPMC）,to better address the real mismatch cases.Three types of non-isolated topologies are compared firstly as the candidates of the SPMC in this paper.After that,a unified output MPPT control structure is proposed accordingly in order to reduce the cost and simplify the SPMC system.The proposed solution saves A/D units,current sensors and MPPT controllers on the premise that all the PV cell strings work on their individual maximum power statue regardless of the mismatch case,which can optimize further integration,simplify the whole SPMC system and make it less expensive.The effectiveness of the circuit is confirmed experimentally.