Research of low voltage ride through control strategy in photovoltaic(PV) grid

With the increasing capacity of grid-connected PV power grids, photovoltaic power generation systems that are connected to the utility grid have shown increasing competitiveness. When the voltage drop occurs due to power short circuit fault, a Low Voltage Ride Through(LVRT) Technology is proposed to improve the stability of the power system. This work, based on the research of PV grid-connected inverter control strategy, the relationship between the positive sequence reactive power, the negative sequence reactive power and the voltage drop depth is established. Although the inverter can not change the grid voltage, But can be achieved through the current control power transmission, through the grid inverter to complete the DC to AC conversion, in order to achieve safe and stable grid-connected photovoltaic power plant, and enhance the stability of the grid system, effectively improve the Photovoltaic inverters are capable of LVRT. MATLAB / SIMULINK simulation to verify the effectiveness of the low-voltage traversal technology.