基于阻抗源的单相光伏并网系统研究

近年来太阳能并网发电系统得到广泛应用,并网逆变器是系统核心部件,系统中逆变器多采用多级式结构。采用阻抗源代替DC/DC升压装置,在升压的同时稳定逆变桥直流侧电压,保证后级逆变器的稳定工作,使并网电流相位严格跟踪电压相位,实现单位功率因数的并网。由于阻抗源不含开关管,允许桥臂直通短路状态的出现,消除了死区时间,降低成本的同时减小了并网电流的谐波畸变,改善了系统输出。采用文献1]中的光伏阵列模型,利用改进的电导增量法实现最大功率点,解决跟踪速度及精度的矛盾,证明基于阻抗源的单相光伏并网系统的可靠性。

Research of Single-phase Grid-connected Photovoltaic System Based on Z-Source

In recent years,the grid-connected photovoltaic（PV） system has been widely used.Grid-connected inverter is the key component of the system.In the system,most of the inverter adopts the hierarchical structure,which simplifies the system control but reducing the system efficiency.The impedance source is adopted to replace the DC/DC device.It boosts and stabilizes the DC link voltage.The phase current follows grid phase voltage strictly in unity power factor.The Z-source does not contain the switch tubes,and the switch tubes in the same arm can conduct at the same time,so it can reduce the costs,eliminate the dead-zone time and reduce the harmonic distortion.Using the photovoltaic array model in reference 1],the maximum power point tracking（MPPT） and the grid-connected operation in unity power factor are achieved.It proves the reliability of single-phase grid-connected photovoltaic system based on Z-source.