Research on low/high voltage ride through of PV grid-connected system based on control-hardware-in-the-loop

Fault ride-through capability is one of the important grid-connection indexes for large-scale generation of PV power and other renewable energy, which is of great significance for the safe and stable operation of the grid. In order to improve the fault ride-through capability of PV grid-connected inverter, a comprehensive control strategy of LVRT/HVRT of PV grid-connected inverter based on conventional control scheme is proposed in this paper. Meanwhile, the LVRT/HVRT test platform of PV grid-connected inverter was built by using the simulation technology of RT-LAB hardware-in-the-loop. Firstly, based on the eHS (electric hardware solver) technology of RT-LAB real-time simulation software, a set of PV grid-connected inverter semi-physical simulation system was built, mainly including PV simulator, PV inverter, filter circuit, three-phase controlled voltage source, etc. Then, according to the technical specification of PV grid-connected inverter, the fault ride-through control strategy of PV grid-connected inverter under the condition of voltage drop/rise symmetrically is proposed. Finally, the simulation tests of LVRT/HVRT were carried out on the simulation platform with the controller of PV inverter. Simulation results show that the proposed control strategy meets the grid-connected requirements during LVRT/HVRT. In addition, it has good dynamic and static characteristics.