Research on the Automatically Independent Controlling Algorithm of the Grid-Connected PV Inverter Jointly Considering Dynamic Load Features and Active LVRT Capability

Abstract

Due to environmental and energy policies in recent years, some countries will install many PV generations into power systems in the future. Under this condition, it is worrisome that the disconnection of the PV occurs because of a voltage drop triggered via a system fault, which impacts the stability of the PV(photovoltaic).A technique of FRT (Fault Ride Through) is an expected solution for PVs. However, just the FRT requirements for PVs do not inevitably increase the stability of the power system. Solving the problem of the instability of the inverter control in a grid-connected PV needs reasonable consideration. This paper proposed an automatically independent controlling algorithm of the PV inverter considering dynamic load features and Active LVRT (low voltage ride through) capability to increase the robustness and performance of the grid-connected PV system, and both simulation and experimental results showed that the condition of a range from an IM rate = 20[%] to an IM rate=40[%] could best meet the requirements for the PV outputting recovery and the average tracking error of the input current reduced by nearly 10%. Also, the average output current tracking error was reduced by about 4%. This shows that the tracking performance has significantly improved.

Keywords

• PV inverter
• fault ride through
• grid-connected
• PV system