一种多输入变换器在光伏DMPPT中的应用

为了解决光伏系统中由于在实际环境中光照不均、阴影遮挡、光伏板老化程度差异等因素导致的失配问题,采用分布式最大功率跟踪DMPPT(distributed maximum power point tracking)结构是有效方法之一。针对光伏DMPPT结构提出了一种基于差额功率结构的多输入变换器拓扑及分时控制策略。该拓扑及控制策略不仅只用1个MPPT控制单元就可完全消除光伏板间的失配问题、使各个光伏板输出其理想最大功率,而且变换器拓扑采用差额功率结构,该结构具有降低变换器的功率等级要求和提高系统的电压增益等优点。对该拓扑及控制策略进行了详细分析,并在Matlab/Simulink中仿真验证。仿真结果表明,即使在光照不均及光照突变的情况下,每个光伏板仍都可以工作在各自理想最大功率点上。

Application of Multiple-input Converter in PV DMPPT Topology

To solve the mismatch problem with a photovoltaic(PV) system caused by uneven illumination, shadow mas-king and aging of PV panels in the practical environment, the structure of distributed maximum power point tracking(DMPPT) is one of the efficient methods. In this paper, a multi-input converter topology based on differential power structure along with a time-sharing control strategy is proposed for the structure of PV DMPPT. On one hand, this topology and control strategy can completely eliminate the mismatch problem between PV panels with only one MPPT control unit, so that each PV panel outputs its ideal maximum power; on the other hand, this converter topology adopts a differential power structure, which has advantages such as reducing the power level requirements of the converter and improving the system voltage gain. The topology and control strategy are analyzed in detail, which are verified through simulations in MATLAB/Simulink. Simulation results show that each PV panel can still operate at its individual ideal maximum power point even under uneven illumination condition as well as with sudden illumination change.