Low Voltage Ride-through Test for Two-level Photovoltaic Grid-connected Inverter Based on RT-LAB

The low voltage ride-through (LVRT) grid-connected performance test of the controller of two-level photovoltaic grid-connected inverter is studied by RT-LAB hardware-in-the-loop (HIL) simulation technology, and a HIL modeling and testing scheme is presented for photovoltaic grid-connected inverter LVRT performance. First, a HIL LVRT test platform, which contains PV array model, voltage sag generator model and photovoltaic inverter power circuit model, is constructed by RT-LAB simulator. Furthermore, a LVRT control strategy under the asymmetric sag fault of grid voltage is designed. Finally, the LVRT HIL simulation test for a 500kW photovoltaic grid-connected inverter using the LVRT control strategy is done in different sag depths and different conditions by RT-LAB simulator, LVRT simulation test results show that the HIL modeling and testing scheme could simulate the on-site testing platform and the proposed control strategy has good dynamic, static characteristics in LVRT process.