Zero-Voltage Ride-Through of Flexible Power Control Strategy in Single-Phase Grid-Connected Photovoltaic Inverters

As an important part of multiple-function and intelligent single-phase grid-connected Photovoltaic (PV) system, fault ride-through (FRT) has attracted extensive attention in the recent years. According to the continuously updated grid-connected requirements, the inverters should remain connected with grid under grid faults even the grid voltage dips to zero, and provide reactive current injection to support the grid recovery. In this paper, a contrastive evaluation of two intuitive and simple flexible power control methods, which are implemented in two different reference frame, are presented in the case of zero-voltage ride-through (ZVRT) operation. Only the dq-rotating reference frame power control method provides an acceptable ability of ZVRT. In addition, the performance is verified in both the simulation and experiment results.