Overview of Outer Loop Control Strategy for Inverters of Micro grid

Micro grid is an effective way to regulate the connection between distributed generation and power grid, which plays an important role in improving the performance of distributed generation. In order to better carry out voltage regulation and frequency regulation operation of micro grid and strengthen the application of distributed generation this paper introduces the typical outer loop control strategy of distributed power grid connected inverter in micro grid, and summarizes the droop control, constant power control and constant frequency control in outer loop control. The principles of these three control methods are analyzed, the applicable situations of each method are introduced, At last, the problems to be solved in current control technology of grid-connected inverter are pointed out, and the future development prospects are prospected.