并联型单开关管光伏组件优化器的研究与设计

Design and Analysis of a Parallel Single-Switch Panel-Integrated PV Optimizer

在光伏发电系统中,因局部阴影遮挡造成的特性失配是引起输出功率降低的重要原因。传统方案大多针对组串及组件失配问题,将每个光伏组件的输出经过变换器独立的最大功率跟踪后再串联加以解决,改变了原有系统连接结构。针对小功率分布式光伏发电系统主要遭遇的组件内失配问题,研究了一种不改变原有光伏组件结构的优化方法,并采用单开关的拓扑实现。该方法在光伏组件遇到局部阴影等造成的组件内特性失配时,可以从光伏组件的输出抽取能量,对受遮挡部分进行补偿,使得各个光伏子串的工作状态可调,从而提高这种情况下的总输出功率。该方法属于部分功率变换,且电路拓扑仅采用单个开关管,控制算法简单,电路损耗和成本较低。仿真和样机实验结果表明,该方法能够显著提高局部阴影条件下光伏组件的输出功率。

In photovoltaic （PV） generation system, the feature mismatch caused by partial shadow effect is a critical problem that leads to the decline of output power of PV panels. Traditional solutions mainly focus on the mismatch among PV panels. Those methods adopt DC-DC converters to perform distributed MPPT for each PV panel while the original system connecting structure has been changed. In this paper, a novel PV parallel optimization method for mismatch problem inside a PV panel is proposed. The optimization method can compensate the unbalanced parts inside PV panel without changing the original panel connection structure. In this paper, the principle of the optimization method is analyzed, and the circuit is implemented by single-switch multi-winding flyback topology. The simulation and experimental results show that the proposed circuit can increase the output power of PV panel under partial shadow condition.