并网逆变系统低压穿越技术研究

Research on Low Voltage Ride Through Technology of Grid-connected Inverter System

逆变器控制系统作为光伏并网发电系统的核心,其设计直接影响整个并网系统的性能﹒随着光伏电站在电力系统中的不断接入,如何提高低压穿越能力成为研究热点﹒本文深入研究单相单级光伏并网逆变系统低压穿越技术,提出了基于单相PQ理论的有功无功电流解耦控制方案﹒该方法可实时对有功电流和无功电流参考进行调整,解决电压跌落过程中的功率不平衡问题,以实现故障期间的功率控制,并将无功功率注入电网以支持电网电压的恢复,最后通过仿真对本文所提出低压穿越技术的正确性和有效性进行了验证﹒

As the core component of the grid-connected PV systems, the design performance of the inverter＇s control system directly affects the performance of the whole system. Meanwhile, with the proportion of the PV power station increasing, the low voltage ride-through ability of the grid-connected PV systems becomes a hot research. In this paper a low voltage ride through （LVRT） method in single-phase single-stage grid-connected PV system is deeply researched. Then, a LVRT method based on the decoupling control of active current and passive current is proposed. The reference values of active current and passive current are adjusting in time to avoid the unbalance of active power and inject passive power to support the grid voltage. Finally, the simulation verifies the correctness and effectiveness of the proposed LVRT technology.