Grid-connected photovoltaic power plants for helping node voltage regulation

This study presents a way of using the photovoltaic power plants for helping the grid to regulate the point of common coupling voltage, not only for injecting active power. This functionality of the photovoltaic resources has become a need as some countries´ standards propose renewable energy to increase the voltage when a sag happens. In addition, this philosophy could also be applied in smart grids where the power must be controlled by the distributed generation. In this study, active power injection is developed by a reference power point tracking and reactive power regulation is carried out by controlling the node voltage, both with dq current control under different power priority possibilities. The generic flow diagram of the control algorithm was implemented on a single-stage traditional inverter topology. The whole system has been checked with a simulation model, including the control algorithm, in order to tune the controller for obtaining the best performance. Finally, an experimental prototype was implemented for validating the proposed node voltage regulating method.