Proportional-resonant Control Method of Three-Phase Grid-Connected Inverter

In recent years, the research on control strategy of three-phase grid-connected inverter has attracted significant attention. Proportion integration (PI) control method is widely utilized to control the grid-connected inverter. However, coordinate transformation is an essential and complex step during the design process of the conventional PI controller. It is difficult to implement in practice due to the complex coordinate transformation. The proportional-resonant (PR) control method of the three-phase grid-connected inverter is proposed, where the conventional PI controller is replaced by PR controller. PR controller has a simple structure as the complex coordinate transformation can be neglected. In order to improve the power factor and the stability of the system, double closed loop structure is also introduced in the proposed control strategy. In the end, simulation software is developed, and the simulation results confirm the effectiveness of the proposed control method.