Z-源逆变器在光伏发电系统中的应用

Study on Z-source Inverter for Photovoltaic Generation System

Z-源逆变器由于采用独特的X型Z-源网络,可以利用逆变器桥臂直通状态实现升压功能,从而使单级Z-源逆变器具有与两级并网系统相类似的性能。该文论述基于Z-源逆变器的光伏并网系统在变换效率、可靠性以及成本方面的优势,提出了一种新的单级Z-源逆变器并网系统两级控制策略,该控制策略实现了MPPT控制和逆变器并网控制,使Z-源光伏并网系统能够动态跟踪光伏电池最大功率点电压,输出电流与电网电压同相位,从而达到较高的功率因数。软件仿真和实验分析证明了该控制方法具有优良的动、静态特性,适合各种变化的天气情况。

With a unique X-type Z-source network, Z-source inverter can utilize the shoot-through state to boost the output voltage as the two-stage dc-ac inverter, which provides an attractive single-stage dc-ac conversion. The PV generation system based on Z-source inverter can achieve some merits, such as high efficiency, high reliability and low cost. This paper proposes a novel control strategy of the Z-source inverter for PV generation system that can track the maximum power point of the PV array and transform power to the utility grid with a unity power factor simultaneously. The simulation and experimental results are also shown to verify that the PV generation system, with proposed control strategy, processes good steady ＆ dynamic performance and leads itself to variable atmosphere.