1kW单级式光伏并网发电系统的设计

Design of 1 kW single-stage photovoltaic grid-connected generation system

针对两级式小功率光伏并网发电系统效率低的缺点,设计了1 k W单级式光伏并网发电系统。对主电路直流侧母线电容和滤波器参数进行设计。单级式光伏并网发电系统结构需要同时控制直流侧母线电压和并网电流,而单闭环系统难以满足需要,采用双闭环控制策略实现并网,分别对电流内环和电压外环进行设计。同时采用锁相环技术,Simulink仿真研究结果表明并网电流能准确跟踪电网电压,实现了系统的高效率并网。

Aiming at the shortcomings of the small power photovoltaic grid-connected generation system with two-stage structure for its low efficiency, a 1 kW photovoltaic grid-connected generation system with single-stage structure was designed. Bus bar capacitance＇s parameter and filter＇s parameter were designed. The bus bar voltage and grid-connected current were both controlled by the system with single-stage structure. However, the requirements couldn＇t be satisfied by the single loop control, the grid-connection should be realized by the double loop control strategy. Grid-connected current inter-loop and bus bar voltage outer-loop were respectively designed. The simulation results with Simulink software show that the grid voltage is tracked by inverter＇s output grid-connected current exactly; the system can be connected to the grid with high efficiency.