分布式光伏发电系统中的微逆变器技术研究

Micro inverter for distributed photovoltaic power system

微逆变器可实现独立的光伏模组最大功率点追踪控制,极大优化并网光伏发电系统的光伏能量转换,提供即插即用概念。光伏微逆变器在功率变换中,常采用高频变压器升压产生期望的输出交流电压,根据直流链配置可以分为直流链、伪直流链和无直流链3种微逆变器拓扑结构。微逆变器控制技术包括最大功率点追踪控制技术、输出电流控制技术、孤岛效应侦测与保证技术等,且功率开关对于改善微逆变器的转换效率至关重要。

The micro inverter, known as module integrated inverter, offers ＂plug and play＂ concept and greatly optimizes the energy yield for grid-connected photovohaic （PV） power systems, for its removal of energy yield mismatches among PV modules and independent maximum power point tracking （MPPT）. A PV micro inverter system often requires a voltage step-up ratio by a high frequency transformer implemented within power conversion stage to produce desired output AC voltage. And the micro inverter topologies are classified into three different arrangements based on the DC Rink configurations. Both control technology such as MPPT, output current control and island effects detecting, and the choice of power switch are also discussed.