Design of Digital PR Controller for L-type Grid-Connected Inverter

As a key link between the DC source and the grid, the L-type grid-connected inverter must have good and stable control performance. In this paper, the current inner loop of L-type inverter is studied and the PR controller is designed by analog method and direct digital method. The performance differences between the discretization methods are compared, and the effect of sampling frequency on the discrete error is also analyzed. In the direct numerical method, the law between the controller parameters and the open-loop root trajectory is analyzed, and two sets of PR controllers are designed based on this. Through simulation experiments, it is verified that the PR controller designed by the direct digital method in this paper can achieve smaller overshoot and faster regulation.