Photovoltaic Equalizer Based on Single-Input Multi-Output Push-Pull Converter

基于单输入多输出推挽变换器的光伏均衡器

¹ School of Automation, Northwestern Polytechnical University, Xi'an 710072, China
² Datang Northwest Electric Power Test&Research Institute, Xi'an 710018, China

Received: 6 July 2019

Abstract

Component mismatch often happens in the module-series photovoltaic system(including centralized, string, multi-strings PV system) due to partial shadowing, which causes a large loss of power generation. Photovoltaic equalizer can process the differential power under the condition of mismatching through parallel power electronic converter without changing the existing photovoltaic system architecture, so that all the modules can work near their maximum power points, which can greatly improve the power generation of the system under the condition of mismatching. This paper proposes a photovoltaic equalizer based on single-input multi-output push-pull converter. The topology has the advantages of simple structure and less switching devices. Firstly, the paper introduces the partial shadowing problem of photovoltaic modules and the principle of photovoltaic equalizer. Then, the topological structure and working principle of the proposed photovoltaic equalizer system are analyzed in detail. Finally, the simulation and verification of the designed photovoltaic equalizer are carried out. The simulated results show that the proposed equalizer can greatly improve the generation capacity of photovoltaic system under mismatching conditions, and the maximum increment can be up to 41%.

摘要

组件串联型光伏系统（包括集中式、组串式、多串式等）由于局部阴影遮蔽常导致组件失配，从而造成较大的发电量损失。光伏均衡器能够在不改变现有光伏系统架构的前提下，通过并联电力电子变换器处理失配条件下的差分功率，从而实现所有组件工作在其最大功率点附近，因而可以大大提升光伏系统在失配条件下的发电量。提出了一种基于单输入多输出推挽变换器的光伏均衡器，该拓扑具有结构简单、开关器件少等优点。首先对光伏组件的遮蔽问题进行了介绍，并对光伏均衡器的原理进行了阐述；继而对所提出的光伏均衡器系统的拓扑结构及工作原理进行详细的分析说明；最后对所设计的光伏均衡器进行仿真验证。仿真结果表明，所提出的光伏均衡器能够大幅提升光伏系统在失配条件下的发电量，最大提升量可达41.4%。