基于Z源逆变器的离网光伏系统仿真设计

对于偏远或电网未覆盖的区域，设计优良的离网光伏系统可解决本地负载的供电问题。将高效Z源逆变器应用于离网光伏系统，提出了系统整体控制策略，在控制离网系统三相交流电压稳定的基础上，同时进行光伏系统最大功率点跟踪（MPPT），额外能量为蓄电池组充电，实现了能源的有效利用。系统仿真结果表明，当交流负载阶跃变化时，系统输出交流电压及MPPT控制仍能快速恢复稳定，蓄电池充电电流也能自行调整，验证了该离网光伏系统的正确性与可行性。

Simulation and Design of Off-grid PV System Based on Z-source Inverter

For remote area where electrical grid is unable to cover, a well-designed off-grid PV system can generate power for local loads. In this paper, the high efficiency Z-source inverter was applied to off-grid PV system. Corresponding control strategy of the whole system was proposed. Based on the stable control of three-phase AC voltage of system, the maximum power point tracing (MPPT) was implemented to charge batteries with additional power, which realized effective energy utilization. The result of simulation show that when the AC step loads changed, the output AC voltage of system and MPPT control can recover to stable state rapidly, and the charging current of batteries can be adjusted automatically. This result verified the accuracy and feasibility of the designed off-grid PV system.