多支路型光伏并网逆变器

Design and operation of multi-string grid-connected PV inverter

阐述了多支路型光伏并网逆变器的基本原理和研制的关键技术。通过对光伏并网逆变器最大功率点跟踪、并网控制技术和孤岛效应等问题的分析,提出了相应的解决方案:采取最大功率跟踪方法,系统能在光强变化时,迅速、准确地跟踪太阳能电池阵列的最大功率点;以多输入支路的独立最大功率跟踪策略,解决了由于太阳能电池阵列参数不一致造成的输出功率降低的问题;在并网逆变技术上采用电流超前跟踪,简单实现了输出功率因数为1,有效地提高了输出电能质量。

The fundamentals and key techniques of multi-string grid-connected PV inverter are introduced in the paper. By analyzing the technique of MPPT, the improved scheme is proposed which can track the maximum power of PV quickly and exactly when the photosphere is variable. By using the inverter topology of multi-string input, each PV input tracks MPP by itself. The problem of different PV parameters that can reduce the output power is solved. The leading current tracking control can realize united output power factor simply, which can improve the quality of output power in effect.