Comparison of control methods for gridconnected voltage source converters in Distributed Generation Systems

The significant growth of Distributed Generation Systems and their integration into electrical grids have tightened the requirements imposed by the Transmission System Operators, especially regarding the regulation of power and the behavior of the power converter during grid faults. In order to fulfil such requirements, such as Low-voltage Ride-through and support the recovery of the grid voltage among others, new control strategies for the grid-side converter have been developed. In this paper a conventional control strategy using proportional-integral controllers and two novel strategies which allow the compliance with such requirements using proportional-integral and proportional plus resonant controllers are presented. The aim is to compare the performance of these control systems, especially the control of both positive and negative reference frames and the improvement of the delivered active power. Finally, simulation results are presented in order to prove the effectiveness and to compare the performance of the presented methods.