A control strategy of low voltage ride-through for grid-connected photovoltaic power system

To improve the low voltage ride-through capability of grid-connected photovoltaic(PV) system, A LVRT control strategy based on voltage oriented vector control is proposed. In the strategy, the voltage oriented vector control for the PV inverter is proposed to realize active and reactive power decoupling control. During the grid voltage sags, the unloading circuit are used to make DC voltage stable, and provide reactive power to support voltage recovery according to the depth of grid voltage sags. The PSCAD/EMDC software is used to compare and analyze each electric parameters before and after LVRT control. The results of simulation show the proposed strategy can make PV power system connected to the grid, provide reactive power to support voltage, and realize LVRT.