Modeling of a Two-Stage Photovoltaic System for Grid Code Compatibility

A complete modeling of two-stage photovoltaic (PV) system operating under large grid disturbances is developed in this study. The grid-integrated PV system are expected to operate through low voltage and provide grid reinforcement by delivering the reactive current during voltage dips, as per most grid standards. Proper current references generation and appropriate controllers design are basis for the effective realization of low voltage ride-through (LVRT) capability. Accordingly, a complete LVRT strategy based on Chinese grid code is developed for PV system under large grid disturbances to enhance power quality and stability. The developed scheme contains the current references computation technique to achieve the provisions of grid code and to guarantee seamless function for PV system under abnormal grid conditions with current amplitude limit functions. Numerous field tests and simulations are performed to evaluate the efficacy of the developed strategy.