An improved low-voltage ride-through (LVRT) strategy for PV-based grid connected inverter using instantaneous power theory

Abstract

This paper presents a low-voltage ride-through technique for large-scale grid tied photovoltaic converters using instantaneous power theory. The control strategy, based on instantaneous power theory, can directly calculate the active and reactive component of currents using measured grid voltage and currents and generate inverter switching pulses based on the formulated reference current values and thus helping to improve the dynamic response when voltage sag takes place. The dynamic response of the proposed model has been compared with both proportional-integral and fuzzy current controllers to judge their suitability. The proposed strategy can provide both active and reactive power support dynamically during grid side fault. The proposed active reactive current control based technique shows better dynamic response compared to existing techniques. The proposed method is tested through appropriate simulation on a practical system to show the effectiveness of the proposed control method.