单相级联H桥光伏并网逆变器控制策略综述

Review of Control Strategies of Single-phase Cascaded H-bridge Inverter for Photovoltaic Grid-connected Systems

为提高光伏发电效率以及减小其体积,分析了级联H桥拓扑结构具有开关器件应力小、输出电压质量高及滤波器体积小等优点。由于其直流侧可由一块光伏组件单独供电,可对每个光伏模块进行最大功率点跟踪,进而越来越多地运用于光伏并网系统来提高系统的发电效率。根据控制策略中功率控制方法的不同,可将级联H桥光伏并网逆变器控制策略分为功率均衡控制和功率不均衡控制。分别对两种方法及优缺点进行了介绍,并结合当今级联H桥光伏并网逆变器的不足对未来发展进行展望。

Cascaded H-bridge has advantages of lower switching device stress,lower harmonic generation and smaller output filter.Its direct current side contains a individual photovoltaic module,which makes independent maximum power point tracking possible,so it is more and more interesting for photovoltaic grid-connected systems to improve the power generation efficiency.According to different control strategies of power control,the control strategies of cascaded H-bridge photovoltaic grid-connected systems can be divided into power balance control and power unbalance control,which are introduced respectively in this thesis.Finally,the future development is prospected combined with the current shortcomings of cascade H-bridge photovoltaic grid-connected inverter.